WorldWideScience

Sample records for air filter samples

  1. RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY AIR FILTER SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Noyes, G.; Culligan, B.

    2010-02-03

    A new rapid method for the determination of actinides and strontium in air filter samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used in emergency response situations. The actinides and strontium in air filter method utilizes a rapid acid digestion method and a streamlined column separation process with stacked TEVA, TRU and Sr Resin cartridges. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha emitters are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The purified {sup 90}Sr fractions are mounted directly on planchets and counted by gas flow proportional counting. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency air filter samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinide and {sup 90}Sr in air filter results were reported in {approx}4 hours with excellent quality.

  2. Problems Found Using a Radon Stripping Algorithm for Retrospective Assessment of Air Filter Samples

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hayes

    2008-04-01

    An evaluation of a large number of air sample filters was undertaken using a commercial alpha and beta spectroscopy system employing a passive implanted planar silicon (PIPS) detector. Samples were only measured after air flow through the filters had ceased. Use of a commercial radon stripping algorithm was implemented to discriminate anthropogenic alpha activity on the filters from the radon progeny. When uncontaminated air filters were evaluated, the results showed that there was a time-dependent bias in both average estimates and measurement dispersion of anthropogenic activity estimates with the relative bias being small compared to the dispersion, indicating that the system would not give false positive indications for an appropriately set decision level. By also measuring environmental air sample filters simultaneously with electroplated alpha filters, use of the radon stripping algorithm demonstrated a number of substantial unexpected deviations from calibrated values indicating that the system would give false negative indications. Use of the current algorithm is, therefore, not recommended for general assay applications. Use of the PIPS detector should only be utilized for gross counting without appropriate modifications to the curve-fitting algorithm. As a screening method, the radon stripping algorithm might be expected to see elevated alpha activities on air sample filters (not due to radon progeny) around the 200 disintegrations per minute level.

  3. Use of a Radon Stripping Algorithm for Retrospective Assessment of Air Filter Samples

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hayes

    2009-01-23

    An evaluation of a large number of air sample filters was undertaken using a commercial alpha and beta spectroscopy system employing a passive implanted planar silicon (PIPS) detector. Samples were only measured after air flow through the filters had ceased. Use of a commercial radon stripping algorithm was implemented to discriminate anthropogenic alpha and beta activity on the filters from the radon progeny. When uncontaminated air filters were evaluated, the results showed that there was a time-dependent bias in both average estimates and measurement dispersion with the relative bias being small compared to the dispersion. By also measuring environmental air sample filters simultaneously with electroplated alpha and beta sources, use of the radon stripping algorithm demonstrated a number of substantial unexpected deviations. Use of the current algorithm is therefore not recommended for assay applications and so use of the PIPS detector should only be utilized for gross counting without appropriate modifications to the curve fitting algorithm. As a screening method, the radon stripping algorithm might be expected to see elevated alpha and beta activities on air sample filters (not due to radon progeny) around the 200 dpm level.

  4. Study of Filter Media for Air-Sampling Purposes

    International Nuclear Information System (INIS)

    A comparative study of six filter media commonly used m monitoring airborne radioactivity has been carried out. The following characteristics were studied: (1) filtration efficiency for uranyl nitrate aerosol and natural activity, (2) pressure drop at various flow rates, (3) absorption factor for alpha particles, (4) use for alpha pulse-height analysis, and (5) physical properties such as tensile strength, thickness, density and ash content. From the results obtained, the order of preference for use in routine monitoring is found to be CWS-6, HV-70, AGF/F, AGF/A, Whatman-41 and Whatman-42. (author)

  5. Results of Self-Absorption Study on the Versapor 3000 Filters for Radioactive Particulate Air Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, J. Matthew; Cullinan, Valerie I.; Barnett, Debra S.; Trang-Le, Truc LT; Bliss, Mary; Greenwood, Lawrence R.; Ballinger, Marcel Y.

    2009-02-17

    Since the mid-1980s, Pacific Northwest National Laboratory (PNNL) has used a value of 0.85 as the correction factor for self absorption of activity for particulate radioactive air samples collected from building exhaust for environmental monitoring. This value accounts for activity that cannot be detected by direct counting of alpha and beta particles. Emissions can be degraded or blocked by filter fibers for particles buried in the filter material or by inactive dust particles collected with the radioactive particles. These filters are used for monitoring air emissions from PNNL stacks for radioactive particles. This paper describes an effort to re-evaluate self-absorption effects in particulate radioactive air sample filters (Versapor® 3000, 47 mm diameter) used at PNNL. There were two methods used to characterize the samples. Sixty samples were selected from the archive for acid digestion to compare the radioactivity measured by direct gas-flow proportional counting of filters to the results obtained after acid digestion of the filter and counting again by gas-flow proportional detection. Thirty different sample filters were selected for visible light microscopy to evaluate filter loading and particulate characteristics. Mass-loading effects were also considered. Filter ratios were calculated by dividing the initial counts by the post-digestion counts with the expectation that post-digestion counts would be higher because digestion would expose radioactivity embedded in the filter in addition to that on top of the filter. Contrary to expectations, the post digestion readings were almost always lower than initial readings and averaged approximately half the initial readings for both alpha and beta activity. Before and after digestion readings appeared to be related to each other, but with a low coefficient of determination (R^2) value. The ratios had a wide range of values indicating that this method did not provide sufficient precision to quantify self

  6. The NYC native air sampling pilot project: using HVAC filter data for urban biological incident characterization.

    Science.gov (United States)

    Ackelsberg, Joel; Leykam, Frederic M; Hazi, Yair; Madsen, Larry C; West, Todd H; Faltesek, Anthony; Henderson, Gavin D; Henderson, Christopher L; Leighton, Terrance

    2011-09-01

    Native air sampling (NAS) is distinguished from dedicated air sampling (DAS) devices (eg, BioWatch) that are deployed to detect aerosol disseminations of biological threat agents. NAS uses filter samples from heating, ventilation, and air conditioning (HVAC) systems in commercial properties for environmental sampling after DAS detection of biological threat agent incidents. It represents an untapped, scientifically sound, efficient, widely distributed, and comparably inexpensive resource for postevent environmental sampling. Calculations predict that postevent NAS would be more efficient than environmental surface sampling by orders of magnitude. HVAC filter samples could be collected from pre-identified surrounding NAS facilities to corroborate the DAS alarm and delineate the path taken by the bioaerosol plume. The New York City (NYC) Native Air Sampling Pilot Project explored whether native air sampling would be acceptable to private sector stakeholders and could be implemented successfully in NYC. Building trade associations facilitated outreach to and discussions with property owners and managers, who expedited contact with building managers of candidate NAS properties that they managed or owned. Nominal NAS building requirements were determined; procedures to identify and evaluate candidate NAS facilities were developed; data collection tools and other resources were designed and used to expedite candidate NAS building selection and evaluation in Manhattan; and exemplar environmental sampling playbooks for emergency responders were completed. In this sample, modern buildings with single or few corporate tenants were the best NAS candidate facilities. The Pilot Project successfully demonstrated that in one urban setting a native air sampling strategy could be implemented with effective public-private collaboration.

  7. HEPA air filter (image)

    Science.gov (United States)

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  8. The sampling of hydrogen sulfide in air with impregnated filter paper

    NARCIS (Netherlands)

    Huygen, C.

    1964-01-01

    A method is proposed for the quantitative collection of hydrogen sulfide in air on impregnated filter paper. An aqueous solution of potassium hydroxide, potassium zincate and glycerol is used as impregnating fluid. The stability of the collected sulfide and the efficiency of collection at different

  9. Methods for detection of fused alumina powder, used as a tracer aerosol, on air sample filters

    International Nuclear Information System (INIS)

    Graded fused aluminia dusts (Aloxite) of mean particle sizes of 6 μm upwards are useful for measuring the effects of particle size on aerosol sampling systems and in dust experiments. Methods are described for the determination of filter loading with Aloxite aerosol using thermoluminescence (TL) and x-ray fluorescence (XRF). The XRF method was found to be almost as precise as direct weighing with a precision microbalance, and presents a useful method of detection where other contaminants are present in the sampled airstream. (author)

  10. Assessment of the Losses Due to Self Absorption by Mass Loading on Radioactive Particulate Air Stack Sample Filters

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Brian M.; Barnett, J. Matthew; Ballinger, Marcel Y.

    2011-01-18

    This report discusses the effect of mass loading of a membrane filter on the self absorption of radioactive particles. A relationship between mass loading and percent loss of activity is presented. Sample filters were collected from Pacific Northwest National Laboratory (PNNL) facilities in order to analyze the current self absorption correction factor of 0.85 that is being used for both alpha and beta particles. Over an eighteen month period from February 2009 to July 2010, 116 samples were collected and analyzed from eight different building stacks in an effort coordinated by the Effluent Management group. Eleven unused filters were also randomly chosen to be analyzed in order to determine background radiation. All of these samples were collected and analyzed in order to evaluate the current correction factor being used.

  11. Early detection of foot-and-mouth disease virus from infected cattle using a dry filter air sampling system

    Science.gov (United States)

    Foot-and-mouth disease (FMD) is a highly contagious livestock disease of high economic impact. Early detection of FMD virus (FMDV) is fundamental for rapid outbreak control. Air sampling collection has been demonstrated as a useful technique for detection of FMDV RNA in infected animals, related to ...

  12. Sample-whitened matched filters

    DEFF Research Database (Denmark)

    Andersen, Ib

    1973-01-01

    A sample-whitened matched filter (SWMF) for a channel with intersymbol interference and additive white Gaussian noise is defined as a linear filter with the properties that its output samples are a sufficient statistic for the MAP estimation of the transmitted sequence and have uncorrelated noise...... components. These filters are shown to exist for ali realistic channels and the complete set of SWMF's for any channel is determined. It is shown that for nonpathological channels there is a unique SWMF which minimizes the amount of intersymbol interference defined as the discrete-time analog to the rms...

  13. Aircraft Recirculation Filter for Air-Quality and Incident Assessment

    OpenAIRE

    Eckels, Steven J.; Jones, Byron; Mann, Garrett; Mohan, Krishnan R.; Weisel, Clifford P.

    2014-01-01

    The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were an...

  14. Interlaboratory evaluation of a standardized inductively coupled plasma mass spectrometry method for the determination of trace beryllium in air filter samples.

    Science.gov (United States)

    Ashley, Kevin; Brisson, Michael J; Howe, Alan M; Bartley, David L

    2009-12-01

    A collaborative interlaboratory evaluation of a newly standardized inductively coupled plasma mass spectrometry (ICP-MS) method for determining trace beryllium in workplace air samples was carried out toward fulfillment of method validation requirements for ASTM International voluntary consensus standard test methods. The interlaboratory study (ILS) was performed in accordance with an applicable ASTM International standard practice, ASTM E691, which describes statistical procedures for investigating interlaboratory precision. Uncertainty was also estimated in accordance with ASTM D7440, which applies the International Organization for Standardization Guide to the Expression of Uncertainty in Measurement to air quality measurements. Performance evaluation materials (PEMs) used consisted of 37 mm diameter mixed cellulose ester filters that were spiked with beryllium at levels of 0.025 (low loading), 0.5 (medium loading), and 10 (high loading) microg Be/filter; these spiked filters were prepared by a contract laboratory. Participating laboratories were recruited from a pool of over 50 invitees; ultimately, 20 laboratories from Europe, North America, and Asia submitted ILS results. Triplicates of each PEM (blanks plus the three different loading levels) were conveyed to each volunteer laboratory, along with a copy of the draft standard test method that each participant was asked to follow; spiking levels were unknown to the participants. The laboratories were requested to prepare the PEMs by one of three sample preparation procedures (hotplate or microwave digestion or hotblock extraction) that were described in the draft standard. Participants were then asked to analyze aliquots of the prepared samples by ICP-MS and to report their data in units of mu g Be/filter sample. Interlaboratory precision estimates from participating laboratories, computed in accordance with ASTM E691, were 0.165, 0.108, and 0.151 (relative standard deviation) for the PEMs spiked at 0.025, 0

  15. Laboratory evaluation of a field-portable sealed source X-ray fluorescence spectrometer for determination of metals in air filter samples.

    Science.gov (United States)

    Lawryk, Nicholas J; Feng, H Amy; Chen, Bean T

    2009-07-01

    Recent advances in field-portable X-ray fluorescence (FP XRF) spectrometer technology have made it a potentially valuable screening tool for the industrial hygienist to estimate worker exposures to airborne metals. Although recent studies have shown that FP XRF technology may be better suited for qualitative or semiquantitative analysis of airborne lead in the workplace, these studies have not extensively addressed its ability to measure other elements. This study involved a laboratory-based evaluation of a representative model FP XRF spectrometer to measure elements commonly encountered in workplace settings that may be collected on air sample filter media, including chromium, copper, iron, manganese, nickel, lead, and zinc. The evaluation included assessments of (1) response intensity with respect to location on the probe window, (2) limits of detection for five different filter media, (3) limits of detection as a function of analysis time, and (4) bias, precision, and accuracy estimates. Teflon, polyvinyl chloride, polypropylene, and mixed cellulose ester filter media all had similarly low limits of detection for the set of elements examined. Limits of detection, bias, and precision generally improved with increasing analysis time. Bias, precision, and accuracy estimates generally improved with increasing element concentration. Accuracy estimates met the National Institute for Occupational Safety and Health criterion for nearly all the element and concentration combinations. Based on these results, FP XRF spectrometry shows potential to be useful in the assessment of worker inhalation exposures to other metals in addition to lead. PMID:19387888

  16. Laboratory evaluation of a field-portable sealed source X-ray fluorescence spectrometer for determination of metals in air filter samples.

    Science.gov (United States)

    Lawryk, Nicholas J; Feng, H Amy; Chen, Bean T

    2009-07-01

    Recent advances in field-portable X-ray fluorescence (FP XRF) spectrometer technology have made it a potentially valuable screening tool for the industrial hygienist to estimate worker exposures to airborne metals. Although recent studies have shown that FP XRF technology may be better suited for qualitative or semiquantitative analysis of airborne lead in the workplace, these studies have not extensively addressed its ability to measure other elements. This study involved a laboratory-based evaluation of a representative model FP XRF spectrometer to measure elements commonly encountered in workplace settings that may be collected on air sample filter media, including chromium, copper, iron, manganese, nickel, lead, and zinc. The evaluation included assessments of (1) response intensity with respect to location on the probe window, (2) limits of detection for five different filter media, (3) limits of detection as a function of analysis time, and (4) bias, precision, and accuracy estimates. Teflon, polyvinyl chloride, polypropylene, and mixed cellulose ester filter media all had similarly low limits of detection for the set of elements examined. Limits of detection, bias, and precision generally improved with increasing analysis time. Bias, precision, and accuracy estimates generally improved with increasing element concentration. Accuracy estimates met the National Institute for Occupational Safety and Health criterion for nearly all the element and concentration combinations. Based on these results, FP XRF spectrometry shows potential to be useful in the assessment of worker inhalation exposures to other metals in addition to lead.

  17. Radioactive air sampling methods

    CERN Document Server

    Maiello, Mark L

    2010-01-01

    Although the field of radioactive air sampling has matured and evolved over decades, it has lacked a single resource that assimilates technical and background information on its many facets. Edited by experts and with contributions from top practitioners and researchers, Radioactive Air Sampling Methods provides authoritative guidance on measuring airborne radioactivity from industrial, research, and nuclear power operations, as well as naturally occuring radioactivity in the environment. Designed for industrial hygienists, air quality experts, and heath physicists, the book delves into the applied research advancing and transforming practice with improvements to measurement equipment, human dose modeling of inhaled radioactivity, and radiation safety regulations. To present a wide picture of the field, it covers the international and national standards that guide the quality of air sampling measurements and equipment. It discusses emergency response issues, including radioactive fallout and the assets used ...

  18. Sequential isotopic determination of plutonium, thorium, americium and uranium in the air filter and drinking water samples around the WIPP site

    International Nuclear Information System (INIS)

    The simultaneous determination of actinides in air filter and water samples around the WIPP site have been demonstrated. The analytical method is based on the selective separation and purification by anion exchange and Eichrome-TEVA, TRU and DGA-resin followed by determination of actinides by alpha spectrometry. Counting sources for alpha spectrometric measurements were prepared by microcoprecipitation on neodymium fluoride (NdF3). Radiochemical yields were determined using 242Pu, 229Th, 243Am and 232U as tracers. The validation of the method is performed through the analysis of reference materials or participating in laboratory intercomparison programs. The plutonium concentrations in aerosols varied seasonally, being highest in spring and summer due to the spring-time enhanced wind-storm transportation of radioactive aerosols from the stratosphere to the troposphere. The 238Pu/239+240Pu activity ratio in the aerosol samples is typically close to that of global fallout from historic above-ground nuclear weapons testing. The results presented here indicate that the source of plutonium in the WIPP environment results mainly from global nuclear fallout and there is no evidence of increases in radiological contaminants in the region that could be attributed to releases from the WIPP. (author)

  19. Air filters for use at nuclear facilities

    International Nuclear Information System (INIS)

    The ventilation system of a nuclear facility plays a vital role in ensuring that the air in working areas and the environment remains free from radioactive contamination. An earlier IAEA publication, Techniques for Controlling Air Pollution from the Operation of Nuclear Facilities, Safety Series No. 17, deals with the design and operation of ventilation systems at nuclear facilities. These systems are usually provided with air-cleaning devices which remove the contaminants from the air. This publication is intended as a guide to those who are concerned with the design of air-filtering systems and with the testing, operation and maintenance of air-filter installations at nuclear facilities. Emphasis is mainly placed on so-called high-efficiency particulate air filters (HEPA filters) and on providing general information on them. Besides describing the usual filter types, their dimensions and construction materials, the guidebook attempts to explain their properties and behaviour under different operating conditions. It also gives advice on testing and handling the filters so that effective and safe performance is ensured. The guidebook should serve as an introduction to the use of high efficiency particulate air filters in countries where work with radioactive materials has only recently commenced. The list of references at the end of the book indicates sources of more advanced information for those who already have comprehensive experience in this field. It is assumed here that the filters are obtained from a manufacturer, and the guidebook thus contains no information on the design and development of the filter itself, nor does it deal with the cleaning of the intake air to a plant, with gas sorption or protective respiratory equipment

  20. Ammonia transformation in a biotrickling air filter

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Nielsen, Marie Louise; Andersen, Mathias;

    2007-01-01

    measurements and model was obtained by using conventional substrate and inhibition kinetics of ammonium and nitrite oxidizing bacteria. Highest rates of ammonia removal were observed in the central section of the filter. Near the air outlet and water inlet the process was ammonia limited, while high nitrous...... acid concentrations almost excluded any biological activity near the air inlet and water outlet. Nitrous acid inhibition also stabilized pH at 6.5-7 all through the filter. Being sensitive to both ammonia and nitrous acid the nitrite oxidation process occurred mainly in the filter sections near the air...... outlet / water inlet, and only 8% of the nitrite was turned into nitrate. Water supply only exceeded evaporation by 20% but modelling indicated that additional watering would have limited effect on filter efficiency. The filter was also robust to varying loading, as a 4-fold increase in ammonia inlet...

  1. High efficiency particulate air filter experience survey

    International Nuclear Information System (INIS)

    Causes and magnitude of HEPA filter changeouts and failures at DOE sites for the years 1977 to 1979 were evaluated. Conclusions inferred from the data follow: HEPA filters have been generally performing the task they were designed for; most changeouts have been made because of filter plugging, preventive maintenance, or precautionary reasons rather than evidence of filter failure; where failures have been experienced, records generally have not been adequate to determine the cause of failure; where cause of failure has been determined, damage attributed to personnel handling and installation has been substantially more prevalent than that from filter environmental exposure. The need for improved personnel training in handling and installation was stressed. Some reduction in filter failure frequency can be achieved by improving the acid and moisture resistance of filters, and providing adequate pretreatment of air prior to HEPA filtration

  2. Initial studies of oxidation processes on filter surfaces and their impack on perceived air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Halás, Oto; Clausen, Geo;

    2003-01-01

    studies, human subjects assessed air passing through various filter samples. This occurred when samples were first placed in the test rig (each of 3 filters equivalent); immediately after the samples had sat for 48 hours in ozone, nitrogen or air (ozone-treated worse than air-treated worse than nitrogen...

  3. Precision temperature controlled filtered laminar air enclosure

    International Nuclear Information System (INIS)

    We demonstrate a novel temperature controlled filtered laminar air enclosure composed of primarily off-the-shelf components that can be applied to a broad class of systems to significantly enhance their performance. An air mixing method is employed to provide variable cooling of the incoming filtered air, providing a temperature stability of ± 0.02 °C within the enclosure. The method is inexpensive to implement, and is suitable for a wide range of temperature controlled enclosures, with dimensions in the approximate range from 1 m to 5 m, making it ideal for many scientific applications. (technical design note)

  4. Performance testing and classification of air filters and particulate air filters. Leistungspruefung und Klassifikation von Luft- und Schwebstoffiltern

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, W.

    1991-09-01

    Standarized rest methods are available for evaluation of the performance of air filters and particulate air filters. While air filters are tested applying the internationally accepted ASHRAE method, standard particulate air filters, or HEPA filters (high-efficiency particulate air), may be tested and classified based on different standards. The methods applied, however, are insufficiently accurate with ragard to high-performance particulate air filters, or ULPA filters (ultralow penetration air). Improved, European-standard test methods are currently being developed. The CEN/TC 195 committee is responsible for the European standardization of air filters and particulate air filters. Details are given about the present situation of air and particulate air filter performance testing and classification. (orig.).

  5. Laboratory experiments on membrane filter sampling of airborne mycotoxins produced by Stachybotrys atra corda

    Science.gov (United States)

    Pasanen, A.-L.; Nikulin, M.; Tuomainen, M.; Berg, S.; Parikka, P.; Hintikka, E.-L.

    A membrane filter method for sampling of airborne stachybotrystoxins was studied in the laboratory. Toxigenic strains of Stachybotrys atra on wallpaper, grain, hay and straw were used as toxin sources in the experiments. Air samples were collected on cellulose nitrate and polycarbonate membrane filters at air flow rates of 10-20 ℓ min -1. After the filter sampling, the air was passed through methanol. The results showed that stachybotrystoxins (trichothecenes) were concentrated in airborne fungal propagules, and thus can be collected on filters. Polycarbonate filters with a pore size of 0.2 μm collected the highest percentage of toxic samples. The laboratory experiments indicated that polycarbonate filter sampling for the collection of airborne mycotoxins is a promising method for extension to field measurements.

  6. Design and Set up of an Air Filter Testing Unit to Demonstrate Characteristics and Performance of Particulate Air Filters

    OpenAIRE

    Ken Smigielski; Farhang Akbar-Khanzadeh

    2009-01-01

    An air filter is a significant element of any mechanical ventilation system. However, the importance and performance evaluation of air filters have not been well publicized and related scientific reports are scarce. In this study, a transportable, off-line, air filter-testing unit (the Unit) was designed and utilized to simulate the filter housing of a mechanical ventilation system. The Unit was designed, assembled, and operated in a laboratory. To demonstrate the applications of the Unit, a ...

  7. Simulation of the air flows in many industrial pleated filters

    International Nuclear Information System (INIS)

    The study presents results concerning the characterization of the charge loss and the air flow in nuclear and automobile type pleated filters. The experimental studies in correlation with the numerical models showed an homogenous distribution of the air flows in a THE nuclear type filter, whereas the distribution is heterogenous in the case of an automobile filter. (A.L.B.)

  8. Design and Set up of an Air Filter Testing Unit to Demonstrate Characteristics and Performance of Particulate Air Filters

    Directory of Open Access Journals (Sweden)

    Ken Smigielski

    2009-04-01

    Full Text Available An air filter is a significant element of any mechanical ventilation system. However, the importance and performance evaluation of air filters have not been well publicized and related scientific reports are scarce. In this study, a transportable, off-line, air filter-testing unit (the Unit was designed and utilized to simulate the filter housing of a mechanical ventilation system. The Unit was designed, assembled, and operated in a laboratory. To demonstrate the applications of the Unit, a series of air filter handling and installation scenarios was performed to determine the characteristic curve and capture efficiencies of a selected set of HEPA filters. The research project produced a transportable, closed system air filter testing unit. The Unit incorporated a fan, a damper to adjust air flowrate, a filter-housing (consisting of a mixing chamber, a filter-frame, and a pressure-gauge, and ducting with ports to introduce challenge particles and monitor them after filtration. By using the Unit, the detrimental effects of damaged filter-media, damaged filter-gasket, and improper installation of air filters on their capture efficiencies were clearly demonstrated. An air filter testing unit, similar to the Unit presented here, can readily be designed, fabricated, and assembled to simulate the filter-housing of mechanical ventilation systems. The assembled unit can be used (1 to determine capture efficiency of air filters and their characteristic curve, (2 to demonstrate the negative effects of improper handling and installation of air filters, and (3 as an effective investigative and educational tool.

  9. Modification of Air Filter Media with Nylon-6 Nanofibers

    OpenAIRE

    Lei Li; Margaret W. Frey; Thomas B. Green

    2006-01-01

    Nylon-6 fibers with average diameters below 500 nm were electrospun onto conventional air filter media at varying weight coverage levels using a multi-nozzle bank. The initial filtration efficiency of the air filter media was improved significantly with increasing coverage level and decreasing size of nylon-6 fibers. Nylon-6 fibers were very durable on the air filter media at the coverage level of 0.1 g/m2 due to the good adhesion with the air filter fibers. The production efficiency of the c...

  10. EML Surface Air Sampling Program, 1990--1993 data

    International Nuclear Information System (INIS)

    Measurements of the concentrations of specific atmospheric radionuclides in air filter samples collected for the Environmental Measurements Laboratory's Surface Air Sampling Program (SASP) during 1990--1993, with the exception of April 1993, indicate that anthropogenic radionuclides, in both hemispheres, were at or below the lower limits of detection for the sampling and analytical techniques that were used to collect and measure them. The occasional detection of 137Cs in some air filter samples may have resulted from resuspension of previously deposited debris. Following the April 6, 1993 accident and release of radionuclides into the atmosphere at a reprocessing plant in the Tomsk-7 military nuclear complex located 16 km north of the Siberian city of Tomsk, Russia, weekly air filter samples from Barrow, Alaska; Thule, Greenland and Moosonee, Canada were selected for special analyses. The naturally occurring radioisotopes that the authors measure, 7Be and 210Pb, continue to be detected in most air filter samples. Variations in the annual mean concentrations of 7Be at many of the sites appear to result primarily from changes in the atmospheric production rate of this cosmogenic radionuclide. Short-term variations in the concentrations of 7Be and 210Pb continued to be observed at many sites at which weekly air filter samples were analyzed. The monthly gross gamma-ray activity and the monthly mean surface air concentrations of 7Be, 95Zr, 137Cs, 144Ce, and 210Pb measured at sampling sites in SASP during 1990--1993 are presented. The weekly mean surface air concentrations of 7Be, 95Zr, 137Cs, 144Ce, and 210Pb for samples collected during 1990--1993 are given for 17 sites

  11. EML Surface Air Sampling Program, 1990--1993 data

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, R.J.; Sanderson, C.G.; Kada, J.

    1995-11-01

    Measurements of the concentrations of specific atmospheric radionuclides in air filter samples collected for the Environmental Measurements Laboratory`s Surface Air Sampling Program (SASP) during 1990--1993, with the exception of April 1993, indicate that anthropogenic radionuclides, in both hemispheres, were at or below the lower limits of detection for the sampling and analytical techniques that were used to collect and measure them. The occasional detection of {sup 137}Cs in some air filter samples may have resulted from resuspension of previously deposited debris. Following the April 6, 1993 accident and release of radionuclides into the atmosphere at a reprocessing plant in the Tomsk-7 military nuclear complex located 16 km north of the Siberian city of Tomsk, Russia, weekly air filter samples from Barrow, Alaska; Thule, Greenland and Moosonee, Canada were selected for special analyses. The naturally occurring radioisotopes that the authors measure, {sup 7}Be and {sup 210}Pb, continue to be detected in most air filter samples. Variations in the annual mean concentrations of {sup 7}Be at many of the sites appear to result primarily from changes in the atmospheric production rate of this cosmogenic radionuclide. Short-term variations in the concentrations of {sup 7}Be and {sup 210}Pb continued to be observed at many sites at which weekly air filter samples were analyzed. The monthly gross gamma-ray activity and the monthly mean surface air concentrations of {sup 7}Be, {sup 95}Zr, {sup 137}Cs, {sup 144}Ce, and {sup 210}Pb measured at sampling sites in SASP during 1990--1993 are presented. The weekly mean surface air concentrations of {sup 7}Be, {sup 95}Zr, {sup 137}Cs, {sup 144}Ce, and {sup 210}Pb for samples collected during 1990--1993 are given for 17 sites.

  12. The high efficiency steel filters for nuclear air cleaning

    International Nuclear Information System (INIS)

    We have, in cooperation with industry, developed high-efficiency filters made from sintered stainless-steel fibers for use in several air-cleaning applications in the nuclear industry. These filters were developed to overcome the failure modes in present high-efficiency particulate air (HEPA) filters. HEPA filters are made from glass paper and glue, and they may fail when they get hot or wet and when they are overpressured. In developing our steel filters, we first evaluated the commercially available stainless-steel filter media made from sintered powder and sintered fiber. The sintered-fiber media performed much better than sintered-powder media, and the best media had the smallest fiber diameter. Using the best media, we then built prototype filters for venting compressed gases and evaluated them in our automated filter tester. 12 refs., 20 figs

  13. High efficiency steel filters for nuclear air cleaning

    International Nuclear Information System (INIS)

    The authors have, in cooperation with industry, developed high-efficiency filters made from sintered stainless-steel fibers for use in several air-cleaning applications in the nuclear industry. These filters were developed to overcome the failure modes in present high-efficiently particulate air (HEPA) filters. HEPA filters are made from glass paper and glue, and they may fail when they get hot or wet and when they are overpressured. In developing steel filters, they first evaluated the commercially available stainless-steel filter media made from sintered powder and sintered fiber. The sintered-fiber media performed much better than sintered-powder media, and the best media had the smallest fiber diameter. Using the best media, prototype filters were then built for venting compressed gases and evaluated in their automated filter tester

  14. Efficiency of dust sampling inlets in calm air.

    Science.gov (United States)

    Breslin, J A; Stein, R L

    1975-08-01

    Measurement of airborne dust concentrations usually involves drawing a sample of the dust-laden air into the measuring instrument through an inlet. Even if the surrounding air is calm, theoretical calculations predict that large particles may not be sampled accurately due to the combined effects of gravity and inertia on the particles near the sampling inlet. Tests were conducted to determine the conditions of particle size, inlet radius, and flow rare necessary for accurate dust sampling. A coal-dust aerosol was sampled simultaneously through inlets of different diameters at the same volume flow-rate and collected on filters. The dust was removed from the filters and the particles were counted and sized with a Coulter counter. Results showed that published criteria for inlet conditions for correct sampling are overly restrictive and that respirable-size particles are sampled correctly in the normal range or operation of most dust sampling instruments. PMID:1227283

  15. Are Ventilation Filters Degrading Indoor Air Quality in California Classrooms?

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.; Destaillats, H.; Apte, M.G.; Destaillats,, Hugo; Fisk, Michael G. Apte and William J.

    2008-10-01

    Heating, ventilating, and cooling classrooms in California consume substantial electrical energy. Indoor air quality (IAQ) in classrooms affects studenthealth and performance. In addition to airborne pollutants that are emitted directly by indoor sources and those generated outdoors, secondary pollutants can be formed indoors by chemical reaction of ozone with other chemicals and materials. Filters are used in nearly all classroom heating, ventilation and air?conditioning (HVAC) systems to maintain energy-efficient HVAC performance and improve indoor air quality; however, recent evidence indicates that ozone reactions with filters may, in fact, be a source of secondary pollutants. This project quantitatively evaluated ozone deposition in HVAC filters and byproduct formation, and provided a preliminary assessment of the extent towhich filter systems are degrading indoor air quality. The preliminary information obtained will contribute to the design of subsequent research efforts and the identification of energy efficient solutions that improve indoor air quality in classrooms and the health and performance of students.

  16. Electrostatic air filters generated by electric fields

    International Nuclear Information System (INIS)

    This paper presents theoretical and experimental findings on fibrous filters converted to electrostatic operation by a nonionizing electric field. Compared to a conventional fibrous filter, the electrostatic filter has a higher efficiency and a longer, useful life. The increased efficiency is attributed to a time independent attraction between polarized fibers and charged, polarized particles and a time dependent attraction between charged fibers and charged, polarized particles. The charge on the fibers results from a dynamic process of charge accumulation due to the particle deposits and a charge dissipation due to the fiber conductivity

  17. Air sampling in the workplace. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hickey, E.E.; Stoetzel, G.A.; Strom, D.J.; Cicotte, G.R. [Pacific Northwest Lab., Richland, WA (United States); Wiblin, C.M. [Advanced Systems Technology, Inc., Atlanta, GA (United States); McGuire, S.A. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Regulatory Applications

    1993-09-01

    This report provides technical information on air sampling that will be useful for facilities following the recommendations in the NRC`s Regulatory Guide 8.25, Revision 1, ``Air sampling in the Workplace.`` That guide addresses air sampling to meet the requirements in NRC`s regulations on radiation protection, 10 CFR Part 20. This report describes how to determine the need for air sampling based on the amount of material in process modified by the type of material, release potential, and confinement of the material. The purposes of air sampling and how the purposes affect the types of air sampling provided are discussed. The report discusses how to locate air samplers to accurately determine the concentrations of airborne radioactive materials that workers will be exposed to. The need for and the methods of performing airflow pattern studies to improve the accuracy of air sampling results are included. The report presents and gives examples of several techniques that can be used to evaluate whether the airborne concentrations of material are representative of the air inhaled by workers. Methods to adjust derived air concentrations for particle size are described. Methods to calibrate for volume of air sampled and estimate the uncertainty in the volume of air sampled are described. Statistical tests for determining minimum detectable concentrations are presented. How to perform an annual evaluation of the adequacy of the air sampling is also discussed.

  18. Report on two intercomparisons on the determination of selected radionuclides in simulated air filters [Air-1/1 and Air-2/1 (1978-1979)

    International Nuclear Information System (INIS)

    The public interest in atmospheric pollution by heavy metals and radioactive contaminants and the need for their reliable determination has convinced the International Atomic Energy Agency of the necessity to continue its programme of intercomparisons of air filter analyses. Several such intercomparison exercises have been organized by the Agency in the past years. The present report deals with a recent intercomparison of activity measurements of air filters spiked with radionuclides. This intercomparison exercise had the aims to provide laboratories dealing with the determination of radionuclides in air filters with an opportunity of checking their analytical performance and, in addition, it was hoped that these simulated air filters would become sufficiently well characterized to be considered later as reference samples with ''recommended'' values for the activities of several radionuclides. The values for 137Cs, 54Mn, 239Pu and 90Sr in Air-1/1 filters seem to be established with a reasonable degree of confidence. The issue of Air-1/1 filters as a reference material for the above radionuclides will follow soon. The comparison of the results of these intercomparison runs with those of the preceding exercises shows on the whole no significant improvement of the quality of analysis. The results of these intercomparison runs show again the difficulties encountered in the determination of radionuclides on air filters. Much effort is still needed to achieve better reliability

  19. Methodology for modeling the microbial contamination of air filters.

    Directory of Open Access Journals (Sweden)

    Yun Haeng Joe

    Full Text Available In this paper, we propose a theoretical model to simulate microbial growth on contaminated air filters and entrainment of bioaerosols from the filters to an indoor environment. Air filter filtration and antimicrobial efficiencies, and effects of dust particles on these efficiencies, were evaluated. The number of bioaerosols downstream of the filter could be characterized according to three phases: initial, transitional, and stationary. In the initial phase, the number was determined by filtration efficiency, the concentration of dust particles entering the filter, and the flow rate. During the transitional phase, the number of bioaerosols gradually increased up to the stationary phase, at which point no further increase was observed. The antimicrobial efficiency and flow rate were the dominant parameters affecting the number of bioaerosols downstream of the filter in the transitional and stationary phase, respectively. It was found that the nutrient fraction of dust particles entering the filter caused a significant change in the number of bioaerosols in both the transitional and stationary phases. The proposed model would be a solution for predicting the air filter life cycle in terms of microbiological activity by simulating the microbial contamination of the filter.

  20. Magnetic analyses of powders from exhausted cabin air filters

    Science.gov (United States)

    Winkler, Aldo; Sagnotti, Leonardo

    2013-04-01

    The automotive cabin air filter is a pleated-paper filter placed in the outside-air intake for the car's passenger compartment. Dirty and saturated cabin air filters significantly reduce the airflow from the outside and introduce particulate matter (PM) and allergens (for example, pollen) into the cabin air stream. Magnetic measurements and analyses have been carried out on powders extracted from exhausted cabin air filters to characterize their magnetic properties and to compare them to those already reported for powders collected from disk brakes, gasoline exhaust pipes and Quercus ilex leaves. This study is also aimed at the identification and quantification of the contribution of the ultrafine fraction, superparamagnetic (SP) at room temperature, to the overall magnetic properties of these powders. This contribution was estimated by interpreting and comparing data from FORCs, isothermal remanent magnetization vs time decay curves, frequency and field dependence of the magnetic susceptibility and out-of-phase susceptibility. The magnetic properties and the distribution of the SP particles are generally homogenous and independent of the brand of the car, of the model of the filter and of its level of usage. The relatively high concentration of magnetic PM trapped in these filters poses relevant questions about the air quality inside a car.

  1. Guidance for air sampling at nuclear facilities

    International Nuclear Information System (INIS)

    The principal uses of air sampling at nuclear facilities are to monitor general levels of radioactive air contamination, identify sources of air contamination, and evaluate the effectiveness of contaminant control equipment, determine exposures of individual workers, and provide automatic warning of hazardous concentrations of radioactivity. These applications of air sampling are discussed with respect to standards of occupational exposure, instrumentation, sample analysis, sampling protocol, and statistical treatment of concentration data. Emphasis is given to the influence of spacial and temporal variations of radionuclide concentration on the location, duration, and frequency of air sampling

  2. Fungal colonization of air filters for use in heating, ventilating, and air conditioning (HVAC) systems.

    Science.gov (United States)

    Simmons, R B; Crow, S A

    1995-01-01

    New and used cellulosic air filters for HVAC systems including those treated with antimicrobials were suspended in vessels with a range of relative humidities (55-99%) and containing non-sterile potting soil which stimulates fungal growth. Most filters yielded fungi prior to suspension in the chambers but only two of 14 nontreated filters demonstrated fungal colonization following use in HVAC systems. Filters treated with antimicrobials, particularly a phosphated amine complex, demonstrated markedly less fungal colonization than nontreated filters. In comparison with nontreated cellulosic filters, fungal colonization of antimicrobial-treated cellulosic filters was selective and delayed.

  3. Design of perfect reconstruction rational sampling filter banks

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The design of rational sampling filter banks based on a recombination structure can be formulated as a problem with two objective functions to be optimized. A new hybrid optimization method for designing perfectreconstruction rational sampling filter banks is presented, which can be used to solve a class of problems with two objective functions. This method is of good convergence and mezzo calculation cost. Satisfactory results free of aliasing in analysis and synthesis filters can be obtained by the proposed method.

  4. Investigation into the behaviour of HEPA filters at high temperature, air humidity, and elevated differential pressure

    International Nuclear Information System (INIS)

    Investigations into the response of full-size HEPA filters to extended operation under high humidity airflows were continued with tests of 47 commercial and 13 prototypical filter units. The parameters studied were relative air humidity or liquid moisture content, temperatures between 20 and 800C, filter loading with dust, exposure time, and filter orientation to airflow. In view of complementary investigations with samples of HEPA-filter media, a laboratory test facility was built and put into operation. Based on the establishment of the main failure mechanisms, new prototype filters, incorporating a filter medium reinforced by glass-fiber cloth and a new separator design with modified corrugations, were built and tested. (orig./DG)

  5. Performance evaluation of PAN nanofiber air filter fabricated by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Cheol; Kim, Tae Eun; Lee, Jung Koo; Ahn, Ji Woong; Park, Sung Ho; Kim, Hyung Man [Dept. of Electronic, Telecommunications, Mechanical and Automotive Engineering, Inje University, Kimhae (Korea, Republic of)

    2015-11-15

    Nanomaterials possess unique mechanical, physical, and chemical properties. They are small, and have an ultrahigh surface area, making them suitable for air filter applications. Electrospinning has been recognized as an efficient technique for fabricating polymer nanofibers. In order to determine the optimum manufacturing conditions, the effects of several electrospinning process parameters on the diameter, orientation, and distribution of polyacrylonitrile (PAN) nanofiber are analyzed. To improve interlaminar fracture toughness and suppress delamination in the form of laminated non-woven fibers by using a heat roller, the performances of filter efficiency and pressure drop achieved with PAN nanofiber air filter are evaluated experimentally.

  6. Mathematical models for changes in HEPA filter pressure drop caused by high air humidity

    International Nuclear Information System (INIS)

    Possible high air humidities resulting from an accident in a nuclear installation threaten the integrity of high-efficiency particulate air (HEPA) filter units in the facility air cleaning systems. Field surveys indicate that filter units continue to be exposed to adverse humidities in routine service despite the development of moisture countermeasures. One of the detrimental consequences of exposure to high air humidity is an increase in filter pressure drop (Δp). Reported failures due to a tearing of the filter medium partly result from elevated structural loadings imposed by Δp increases. The extent to which filter Δp varies with airstream conditions can be used to help calculate safety margins for filter units during normal and upset operations as well as during postulated accidents involving high air humidity. Studies of humidity-related changes in pressure drop were carried out to help explain structural failures in routine service and to obtain the empirical data needed to numerically model flow dynamics in air cleaning systems under accident conditions. Tests were performed on full-scale filter units under fog conditions and on samples of filter media at humidities up to 99% RH. Test results show that typical changes in Δp can be mathematically modeled by a number of time functions having coefficients that can only be determined empirically. Regression analysis is used to establish the coefficients for specific filter units and dust loadings tested under the operating conditions of interest. Comparison of measured and calculated increases in pressure drop for clean filter units under fog conditions show that good agreement can be obtained with coefficients determined as relatively simple functions of the airstream velocity and liquid water content

  7. High efficiency particulate air filter behavior under high humidity airflows

    International Nuclear Information System (INIS)

    A loss-of-coolant accident could threaten the integrity of the HEPA filters in the air cleaning systems of a nuclear power reactor with airflows of high humidity, elevated temperature, and greater than design flow rate. It is important that filter reliability be assured during accident situations since a loss of filter integrity could result in a loss of containment. The average failure differential pressure at 1700 m3/h for three commercial filter designs under conditions of high air humidity at 500C were found to lie between 0.7 and 7.6 kPa. The modes and mechanisms of structural failure were determined for wooden frame deep pleat filters, the design with the most potential for improvement. Initial tests of prototype filter units with a glass fiber medium reinforced by fiber glass cloth proved that structural limits could be increased to at least 10 kPa even with significant decreases in the lateral stability of the filter pack. A similar test of a prototype filter equipped with a special arrangement of the separators and a conventional glass fiber medium showed that pack stability could be maintained during fog conditions that cause failure of conventional glass fiber filters within several hours

  8. Gross Alpha Beta Radioactivity in Air Filters Measured by Ultra Low Level α/β Counter

    Science.gov (United States)

    Cfarku, Florinda; Bylyku, Elida; Deda, Antoneta; Dhoqina, Polikron; Bakiu, Erjona; Perpunja, Flamur

    2010-01-01

    Study of radioactivity in air as very important for life is done regularly using different methods in every country. As a result of nuclear reactors, atomic centrals, institutions and laboratories, which use the radioactivity substances in open or closed sources, there are a lot radioactive wastes. Mixing of these wastes after treatment with rivers and lakes waters makes very important control of radioactivity. At the other side nuclear and radiological accidents are another source of the contamination of air and water. Due to their radio toxicity, especially those of Sr90, Pu239, etc. a contamination hazard for human begins exist even at low concentration levels. Measurements of radioactivity in air have been performed in many parts of the world mostly for assessment of the doses and risk resulting from consuming air. In this study we present the results of international comparison organized by IAEA Vienna, Austria for the air filters spiked with unknown Alpha and Beta Activity. For the calibration of system we used the same filters spiked: a) with Pu-239 as alpha source; b) Sr-90 as beta source and also the blank filter. The measurements of air filter samples after calibration of the system are done with Ultra Low Level α/β Counter (MPC 9604) Protean Instrument Corporation. The high sensitivity of the system for the determination of the Gross Alpha and Beta activity makes sure detection of low values activity of air filters. Our laboratory results are: Aα = (0.19±0.01) Bq/filter and Aα (IAEA) = (0.17±0.009) Bq/filter; Aβ = (0.33±0.009) Bq/filter and Aβ (IAEA) = (0.29±0.01) Bq/filter. As it seems our results are in good agreement with reference values given by IAEA (International Atomic Energy Agency).

  9. Self-Cleaning Particulate Air Filter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA requires an innovative solution to the serious issue of particulate fouling on air revitalization component surfaces in order to address the potential for...

  10. Design and development of high performance panel air filter with experimental evaluation and analysis of filter media pleats

    OpenAIRE

    Sagar R. Patil; Prof. Sachin V. Lomte

    2015-01-01

    In automobile vehicles mostly plastic molded panel filters used for the purpose of engine air filtration. Fibrous structured cellulose media were being used with different permeability’s according to requirement of rated air flow rate required for the engine. To optimize the filter pleat design of automotive panel air filter, it is important to study correlation of pressure drop, dust holding capacity & efficiency. The main role of a filter is to provide least pressure drop with h...

  11. Sampling, Filtering and Sparse Approximations on Combinatorial Graphs

    CERN Document Server

    Pesenson, Isaac Z

    2011-01-01

    In this paper we address sampling and approximation of functions on combinatorial graphs. We develop filtering on graphs by using Schr\\"odinger's group of operators generated by combinatorial Laplace operator. Then we construct a sampling theory by proving Poincare and Plancherel-Polya-type inequalities for functions on graphs. These results lead to a theory of sparse approximations on graphs and have potential applications to filtering, denoising, data dimension reduction, image processing, image compression, computer graphics, visualization and learning theory.

  12. Efficiency of Sampling and Analysis of Asbestos Fibers on Filter Media: Implications for Exposure Assessment

    Science.gov (United States)

    To measure airborne asbestos and other fibers, an air sample must represent the actual number and size of fibers. Typically, mixed cellulose ester (MCE, 0.45 or 0.8 µm pore size) and to a much lesser extent, capillary-pore polycarbonate (PC, 0.4 µm pore size) membrane filters are...

  13. Local Importance Sampling: A Novel Technique to Enhance Particle Filtering

    Directory of Open Access Journals (Sweden)

    Péter Torma

    2006-04-01

    Full Text Available In the low observation noise limit particle filters become inefficient. In this paper a simple-to- implement particle filter is suggested as a solution to this well-known problem. The proposed Local Importance Sampling based particle filters draw the particles’ positions in a two-step process that makes use of both the dynamics of the system and the most recent observation. Experiments with the standard bearings-only tracking problem indicate that the proposed new particle filter method is indeed very successful when observations are reliable. Experiments with a high-dimensional variant of this problem further show that the advantage of the new filter grows with the increasing dimensionality of the system.

  14. Combined filtering facilities for nuclear air cleaning systems

    International Nuclear Information System (INIS)

    Full text of publication follows: The choice of an optimal cleaning technology and cleaning system design depends on the specificity of the provision of the ecological safety of NPP under operation and accident conditions. The major requirements imposed on such systems are to achieve high efficiency (99,0-99,95 %) and reliability. In this respect, the important problem is to develop combined filtering facilities (CFF) which are able within the same aggregate to provide complex cleaning of air from moisture, radioactive aerosols, iodine in molecular (I2) and organic (CH3I) forms. A great experience accumulated at SSC RF IPPE and other organizations in the course of researches dealing with construction of aerosol filters and iodine filters-sorbers for NPPs and radio-chemical plants made it possible to develop a pilot mock-up facility providing complex cleaning of air from radioactive aerosols and iodine in reference to the real ventilation conditions at the First in the World Nuclear Power Plant. By now complex tests of the mock-up specimen of the UFK-3500 facility have been run with the aim of determining the functional efficiency of its separate filtering sections in terms of droplet moisture, atmospheric and radioactive aerosols and radioiodine and its organic compounds as well as of the filtering facility as a whole. Control over aerosol and radioiodine concentrations and volumetric activity was performed using laser and gamma spectrometry. The obtained data give necessary grounds to formulate the recommendations, how to develop and organize production of combined filtering facilities for flow rates of the medium to be cleaned of 3500, 7000, 10500 m3/h. The production is organized on the basis of OAO PZ 'Signal' in Obninsk. Provision is made for using small capacity small size filters (for radiochemical plants and research test facilities and rigs) and high efficiency sorbers (for commercial NPP) as filters-sorbers. To date the design plans and specifications

  15. Cabin Air Sampling Study Functionality Test.

    OpenAIRE

    Muir, Helen; Walton, Christopher; McKeown, Rebecca

    2008-01-01

    The Department for Transport (DFT), on behalf of the Government’s Aviation Health Working Group (AHWG), commissioned Cranfield University to organise, manage and deliver a functionality test of a variety of air sampling devices capable of detecting a wide range of compounds in a cabin air environment. The functionality test was to be the preliminary stage of a major monitoring study of the cabin air environment, which the Department intends to conduct. Report prepared for the Department f...

  16. A nested sampling particle filter for nonlinear data assimilation

    KAUST Repository

    Elsheikh, Ahmed H.

    2014-04-15

    We present an efficient nonlinear data assimilation filter that combines particle filtering with the nested sampling algorithm. Particle filters (PF) utilize a set of weighted particles as a discrete representation of probability distribution functions (PDF). These particles are propagated through the system dynamics and their weights are sequentially updated based on the likelihood of the observed data. Nested sampling (NS) is an efficient sampling algorithm that iteratively builds a discrete representation of the posterior distributions by focusing a set of particles to high-likelihood regions. This would allow the representation of the posterior PDF with a smaller number of particles and reduce the effects of the curse of dimensionality. The proposed nested sampling particle filter (NSPF) iteratively builds the posterior distribution by applying a constrained sampling from the prior distribution to obtain particles in high-likelihood regions of the search space, resulting in a reduction of the number of particles required for an efficient behaviour of particle filters. Numerical experiments with the 3-dimensional Lorenz63 and the 40-dimensional Lorenz96 models show that NSPF outperforms PF in accuracy with a relatively smaller number of particles. © 2013 Royal Meteorological Society.

  17. Preparation, certification and interlaboratory analysis of workplace air filters spiked with high-fired beryllium oxide.

    Science.gov (United States)

    Oatts, Thomas J; Hicks, Cheryl E; Adams, Amy R; Brisson, Michael J; Youmans-McDonald, Linda D; Hoover, Mark D; Ashley, Kevin

    2012-02-01

    Occupational sampling and analysis for multiple elements is generally approached using various approved methods from authoritative government sources such as the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), as well as consensus standards bodies such as ASTM International. The constituents of a sample can exist as unidentified compounds requiring sample preparation to be chosen appropriately, as in the case of beryllium in the form of beryllium oxide (BeO). An interlaboratory study was performed to collect analytical data from volunteer laboratories to examine the effectiveness of methods currently in use for preparation and analysis of samples containing calcined BeO powder. NIST SRM(®) 1877 high-fired BeO powder (1100 to 1200 °C calcining temperature; count median primary particle diameter 0.12 μm) was used to spike air filter media as a representative form of beryllium particulate matter present in workplace sampling that is known to be resistant to dissolution. The BeO powder standard reference material was gravimetrically prepared in a suspension and deposited onto 37 mm mixed cellulose ester air filters at five different levels between 0.5 μg and 25 μg of Be (as BeO). Sample sets consisting of five BeO-spiked filters (in duplicate) and two blank filters, for a total of twelve unique air filter samples per set, were submitted as blind samples to each of 27 participating laboratories. Participants were instructed to follow their current process for sample preparation and utilize their normal analytical methods for processing samples containing substances of this nature. Laboratories using more than one sample preparation and analysis method were provided with more than one sample set. Results from 34 data sets ultimately received from the 27 volunteer laboratories were subjected to applicable statistical analyses. The observed

  18. Performance Analysis of Upsample Filter for Sample Rate Converter

    Directory of Open Access Journals (Sweden)

    Manish Sabraj

    2012-03-01

    Full Text Available Now a days many signal processing tasks are performed in the digital domain. Various sample rates are used on the basis of required signal quality and the available bandwidth. Sample-rate conversion is therefore inevitable to interface systems with different sample rates. The aim of digital sample rate conversion is to bring a digital audio signal from one sample frequency to another. Some information is lost while sampling.The distortion of the audio signal introduced by the sample rate converter should be as low as possible. The generation of the output samples from the input samples may be performed by the application of various techniques, In this paper, a new technique of digital sample-rate converter is proposed. We discuss performance analysis of upsample filter in proposed digital sample rate converter.

  19. Performance Analysis of Upsample Filter for Sample Rate Converter

    Directory of Open Access Journals (Sweden)

    Manish Sabraj

    2012-02-01

    Full Text Available Now a days many signal processing tasks are performed in the digital domain. Various sample rates are used on the basis of required signal quality and the available bandwidth. Sample-rate conversion is therefore inevitable to interface systems with different sample rates. The aim of digital sample rate conversion is to bring a digital audio signal from one sample frequency to another. Some information is lost while sampling.The distortion of the audio signal introduced by the sample rate converter should be as low as possible. The generation of the output samples from the input samples may be performed by the application of various techniques, In this paper, a new technique of digital sample-rate converter is proposed. We discuss performance analysis of upsample filter in proposed digital sample rate converter.

  20. Assessment of the 3410 Building Filtered Exhaust Stack Sampling Probe Location

    Energy Technology Data Exchange (ETDEWEB)

    Glissmeyer, John A.; Flaherty, Julia E.

    2010-07-16

    Pacific Northwest National Laboratory performed several tests in the exhaust air discharge from the new 3410 Building Filtered Exhaust Stack to determine whether the air sampling probe for emissions monitoring for radionuclides is acceptable. The method followed involved adopting the results of a previously performed test series from a system with a similar configuration, followed by several tests on the actual system to verify the applicability of the previously performed tests. The qualification criteria for these types of stacks include metrics concerning 1) uniformity of air velocity, 2) sufficiently small flow angle with respect to the axis of the duct, 3) uniformity of tracer gas concentration, and 4) uniformity tracer particle concentration.

  1. Assessment of the 3420 Building Filtered Exhaust Stack Sampling Probe Location

    Energy Technology Data Exchange (ETDEWEB)

    Glissmeyer, John A.; Flaherty, Julia E.

    2010-07-16

    Pacific Northwest National Laboratory performed several tests in the exhaust air discharge from the new 3420 Building Filtered Exhaust Stack to determine whether the air sampling probe for emissions monitoring for radionuclides is acceptable. The method followed involved adopting the results of a previously performed test series from a system with a similar configuration, followed by several tests on the actual system to verify the applicability of the previously performed tests. The qualification criteria for these types of stacks include metrics concerning 1) uniformity of air velocity, 2) sufficiently small flow angle with respect to the axis of the duct, 3) uniformity of tracer gas concentration, and 4) uniformity tracer particle concentration.

  2. Penggunaan Unit Slow Sand Filter, Ozon Generator dan Rapid Sand Filter untuk Meningkatkan Kualitas Air Sumur Dangkal menjadi Air Layak Minum dengan Parameter Kekeruhan, Fe, dan Mn

    Directory of Open Access Journals (Sweden)

    Jami’ah Jami’ah

    2014-09-01

    Full Text Available Air tanah dapat diambil masyarakat untuk keperluan sehari-hari. Air tanah terkadang belum memenuhi standar kualitas air minum karena adanya kadar besi, mangan dan kekeruhan yang tinggi. Dari permasalahan tersebut diperlukan adanya teknologi pengolahan yang efektif dan efisien bagi masyarakat. Slow sand filter, proses ozonisasi dan rapid sand filter dapat menjadi alternatif pengolahan air sumur dangkal tercemar menjadi air layak minum.Tujuan dari penelitian ini yaitu untuk menganalisa kemampuan unit slow sand filter, ozon generator dan rapid sand filter dalam menyisihkan besi, mangan, dan kekeruhan yang terkandung dalam air minum.Hasil penelitian menunjukkan bahwa efisiensi removal pada unit slow sand filter untuk beban besi, mangan dan kekeruhan adalah (84,13%; 4842%; 89,21%, pada proses ozonisasi (75,4%; 47,4%; 35,83%, dan pada unit rapid sand filter (79,63%; 72,2%; 64,94%.

  3. Generic Hardware Architectures for Sampling and Resampling in Particle Filters

    Directory of Open Access Journals (Sweden)

    Petar M. Djurić

    2005-10-01

    Full Text Available Particle filtering is a statistical signal processing methodology that has recently gained popularity in solving several problems in signal processing and communications. Particle filters (PFs have been shown to outperform traditional filters in important practical scenarios. However their computational complexity and lack of dedicated hardware for real-time processing have adversely affected their use in real-time applications. In this paper, we present generic architectures for the implementation of the most commonly used PF, namely, the sampling importance resampling filter (SIRF. These provide a generic framework for the hardware realization of the SIRF applied to any model. The proposed architectures significantly reduce the memory requirement of the filter in hardware as compared to a straightforward implementation based on the traditional algorithm. We propose two architectures each based on a different resampling mechanism. Further, modifications of these architectures for acceleration of resampling process are presented. We evaluate these schemes based on resource usage and latency. The platform used for the evaluations is the Xilinx Virtex II pro FPGA. The architectures presented here have led to the development of the first hardware (FPGA prototype for the particle filter applied to the bearings-only tracking problem.

  4. [Sick building syndrome and HVAC system: MVOC from air filters].

    Science.gov (United States)

    Schleibinger, H W; Wurm, D; Möritz, M; Böck, R; Rüden, H

    1997-08-01

    Growth and emissions of volatile metabolites of microorganisms on air filters are suspected to contribute to health complaints in ventilated rooms. To prove the microbiological production of volatile organic compounds (MVOC), concentrations of aldehydes and ketones were determined in two large HVAC systems. The in situ derivated aldehydes and ketones (as 2,4-dinitrophenyl-hydrazones) were analysed by HPLC and UV detection. The detection limit of each compound was 1 ppb (margin of error HVAC systems. First results show that the compounds formaldehyde, acetaldehyde and acetone could be detected before and after the filters. The concentrations of these VOC after the filters were significantly increased--as a mean over twenty measurements--, especially as far as filters made of glass fibre are concerned. However the found concentrations were low and mostly comparable to outdoor findings. In simultaneous laboratory experiments pieces of used filter material of one HVAC system and unused filter pieces (for blank values) were examined in small incubation chambers to investigate the possible production of MVOC. For the incubation a temperature of 20 degrees C and a relative humidity of 95% was chosen. In these experiments an almost identical spectrum of compounds (formaldehyde and acetone) was found as in the field measurements. The concentrations of these compounds were higher in the chambers with the used filter pieces. The concentration of acetone ranged up to almost 12 mg/m3.--As our field experiments correspond with our laboratory experiments, we assume that the microbial production of volatile organic compounds in HVAC systems under operating conditions is possible.

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

    International Nuclear Information System (INIS)

    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)

  6. Use of dust fall filters as passive samplers for metal concentrations in air for communities near contaminated mine tailings

    Science.gov (United States)

    Beamer, P.I.; Sugeng, A. J.; Kelly, M.D.; Lothrop, N.; Klimecki, W.; Wilkinson, S.T.; Loh, M.

    2014-01-01

    Mine tailings are a source of metal exposures in many rural communities. Multiple air samples are necessary to assess the extent of exposures and factors contributing to these exposures. However, air sampling equipment is costly and requires trained personnel to obtain measurements, limiting the number of samples that can be collected. Simple, low-cost methods are needed to allow for increased sample collection. The objective of our study was to assess if dust fall filters can serve as passive air samplers and be used to characterize potential exposures in a community near contaminated mine tailings. We placed filters in cylinders, concurrently with active indoor air samplers, in 10 occupied homes. We calculated an estimated flow rate by dividing the mass on each dust fall filter by the bulk air concentration and the sampling duration. The mean estimated flow rate for dust fall filters was significantly different during sampling periods with precipitation. The estimated flow rate was used to estimate metal concentration in the air of these homes, as well as in 31 additional homes in another rural community impacted by contaminated mine tailings. The estimated air concentrations had a significant linear association with the measured air concentrations for beryllium, manganese and arsenic (p<0.05), whose primary source in indoor air is resuspended soil from outdoors. In the second rural community, our estimated metal concentrations in air were comparable to active air sampling measurements taken previously. This passive air sampler is a simple low-cost method to assess potential exposures near contaminated mining sites. PMID:24469149

  7. A comparison of portable XRF and ICP-OES analysis for lead on air filter samples from a lead ore concentrator mill and a lead-acid battery recycler.

    Science.gov (United States)

    Harper, Martin; Pacolay, Bruce; Hintz, Patrick; Andrew, Michael E

    2006-03-01

    Personal and area samples for airborne lead were taken at a lead mine concentrator mill, and at a lead-acid battery recycler. Lead is mined as its sulfidic ore, galena, which is often associated with zinc and silver. The ore typically is concentrated, and partially separated, on site by crushing and differential froth flotation of the ore minerals before being sent to a primary smelter. Besides lead, zinc and iron are also present in the airborne dusts, together with insignificant levels of copper and silver, and, in one area, manganese. The disposal of used lead-acid batteries presents environmental issues, and is also a waste of recoverable materials. Recycling operations allow for the recovery of lead, which can then be sold back to battery manufacturers to form a closed loop. At the recycling facility lead is the chief airborne metal, together with minor antimony and tin, but several other metals are generally present in much smaller quantities, including copper, chromium, manganese and cadmium. Samplers used in these studies included the closed-face 37 mm filter cassette (the current US standard method for lead sampling), the 37 mm GSP or "cone" sampler, the 25 mm Institute of Occupational Medicine (IOM) inhalable sampler, the 25 mm Button sampler, and the open-face 25 mm cassette. Mixed cellulose-ester filters were used in all samplers. The filters were analyzed after sampling for their content of the various metals, particularly lead, that could be analyzed by the specific portable X-ray fluorescence (XRF) analyzer under study, and then were extracted with acid and analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The 25 mm filters were analyzed using a single XRF reading, while three readings on different parts of the filter were taken from the 37 mm filters. For lead at the mine concentrate mill, all five samplers gave good correlations (r2 > 0.96) between the two analytical methods over the entire range of found lead mass

  8. Measurement of radon daughters in air samples by alpha spectroscopy

    International Nuclear Information System (INIS)

    The concentration of radon progeny in air has been determined by alpha spectrometry measurement of polonium 214 and polonium 218. A known volume of air was passed through a filter, then the alpha activity was directly measured on this filter (Author)

  9. Transparent air filter for high-efficiency PM2.5 capture

    Science.gov (United States)

    Liu, Chong; Hsu, Po-Chun; Lee, Hyun-Wook; Ye, Meng; Zheng, Guangyuan; Liu, Nian; Li, Weiyang; Cui, Yi

    2015-02-01

    Particulate matter (PM) pollution has raised serious concerns for public health. Although outdoor individual protection could be achieved by facial masks, indoor air usually relies on expensive and energy-intensive air-filtering devices. Here, we introduce a transparent air filter for indoor air protection through windows that uses natural passive ventilation to effectively protect the indoor air quality. By controlling the surface chemistry to enable strong PM adhesion and also the microstructure of the air filters to increase the capture possibilities, we achieve transparent, high air flow and highly effective air filters of ~90% transparency with >95.00% removal of PM2.5 under extreme hazardous air-quality conditions (PM2.5 mass concentration >250 μg m-3). A field test in Beijing shows that the polyacrylonitrile transparent air filter has the best PM2.5 removal efficiency of 98.69% at high transmittance of ~77% during haze occurrence.

  10. A comparison of two extended Kalman filter algorithms for air-to-air passive ranging.

    OpenAIRE

    Ewing, Ward Hubert.

    1983-01-01

    Approved for public release; distribution is unlimited Two Extended Kalman Filter algorithms for air-to-air passive ranging are proposed, and examined by computer simulation. One algorithm uses only bearing observations while the other uses both bearing and elevation angles. Both are tested using a flat-Earth model and also using a spherical-Earth model where the benefit of a simple correction for the curvature-of-the-Earth effect on elevation angle is examined. The effects of varied an...

  11. Tests on the sampling performance of 3 kinds of filters for α-radioactive aerosol sampling

    International Nuclear Information System (INIS)

    Filter for α-radioactive aerosol sampling is one of the important parts in radioactive aerosol detection. Filter with high efficiency, low self-absorption and high-performed surface collection will improve the speed of monitoring and energy resolution of α. In this study, 3 different types of filters were chosen for sampling of natural radon daughter aerosol. The parameters of collection efficiency, self-absorption, surface collection characteristics and flow rate under the same resistance were measured. In the same condition of the aerosol concentration, sampling flow rate and sampling time, the membrane filter which is made of mixed cellulose ester with the mean pore radius of 0.8 μm, has the highest filter efficiency and less self-absorption; heavy-ion microporous membrane with pore radius of 0.4μm has minimal self-absorption and superior surface collection, which is important in improving the α energy resolution; the glass fiber filter has the lowest resistance, suiting for large flow rate in sampling. (authors)

  12. Capability of air filters to retain airborne bacteria and molds in heating, ventilating and air-conditioning (HVAC) systems.

    Science.gov (United States)

    Möritz, M; Peters, H; Nipko, B; Rüden, H

    2001-07-01

    The capability of air filters (filterclass: F6, F7) to retain airborne outdoor microorganisms was examined in field experiments in two heating, ventilating and air conditioning (HVAC) systems. At the beginning of the 15-month investigation period, the first filter stages of both HVAC systems were equipped with new unused air filters. The number of airborne bacteria and molds before and behind the filters were determined simultaneously in 14 days-intervals using 6-stage Andersen cascade impactors. Under relatively dry ( 12 degrees C) outdoor air conditions air filters led to a marked reduction of airborne microorganism concentrations (bacteria by approximately 70% and molds by > 80%). However, during long periods of high relative humidity (> 80% R. H.) a proliferation of bacteria on air filters with subsequent release into the filtered air occurred. These microorganisms were mainly smaller than 1.1 microns therefore being part of the respirable fraction. The results showed furthermore that one possibility to avoid microbial proliferation is to limit the relative humidity in the area of the air filters to 80% R. H. (mean of 3 days), e.g. by using preheaters in front of air filters in HVAC-systems.

  13. K West Basin Sand Filter Backwash Sample Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smoot, Margaret R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Coffey, Deborah S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pool, Karl N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-01

    A sand filter is used to help maintain water clarity at the K West Basin where highly radioactive sludge is stored. Eventually that sand filter will require disposal. The radionuclide content of the solids trapped in the sand filter will affect the selection of the sand filter disposal pathway. The Pacific Northwest National Laboratory (PNNL) was contracted by the K Basin Operations & Plateau Remediation Project (operations contractor CH2M Hill) to analyze the radionuclide content of the solids collected from the backwash of the K West Basin sand filter. The radionuclide composition in the sand filter backwash solids will be used by CH2M Hill to determine if the sand filter media and retained sludge solids will be designated as transuranic waste for disposal purposes or can be processed through less expensive means. On October 19, 2015, K Basin Operations & Plateau Remediation Project staff backwashed the sand filter into the North Load-Out Pit (NLOP) and immediately collected sample slurry from a sampling tube positioned 24 in. above the NLOP floor. The 764 g sand filter backwash slurry sample, KW-105 SFBW-001, was submitted to PNNL for analysis on October 20, 2015. Solids from the slurry sample were consolidated into two samples (i.e., a primary and a duplicate sample) by centrifuging and measured for mass (0.82 g combined – wet centrifuged solids basis) and volume (0.80 mL combined). The solids were a dark brown/orange color, consistent with iron oxide/hydroxide. The solids were dried; the combined dry solids mass was 0.1113 g, corresponding to 0.0146 weight percent (wt%) solids in the original submitted sample slurry. The solids were acid-digested using nitric and hydrochloric acids. Insoluble solids developed upon dilution with 0.5 M HNO3, corresponding to an average 6.5 wt% of the initial dry solids content. The acid digestate and insoluble solids were analyzed separately by gamma spectrometry. Nominally, 7.7% of the 60Co was present

  14. Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters

    Science.gov (United States)

    Calfee, M. Worth; Rose, Laura J.; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

    2016-01-01

    The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37 mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50% of their total holding capacity. The results were analyzed by one-way ANOVA across material types, presence or absence of dust, and sampling device. The extraction method gave higher relative recoveries than the two vacuum methods evaluated (p ≤ 0.001). On average, recoveries obtained by the vacuum methods were about 30% of those achieved by the extraction method. Relative recoveries between the two vacuum methods were not significantly different (p > 0.05). Although extraction methods yielded higher recoveries than vacuum methods, either HVAC filter sampling approach may provide a rapid and inexpensive mechanism for understanding the extent of contamination following a wide-area biological release incident. PMID:24184312

  15. Digital timing: sampling frequency, anti-aliasing filter and signal interpolation filter dependence on timing resolution

    International Nuclear Information System (INIS)

    The main focus of our study is to investigate how the performance of digital timing methods is affected by sampling rate, anti-aliasing and signal interpolation filters. We used the Nyquist sampling theorem to address some basic questions such as what will be the minimum sampling frequencies? How accurate will the signal interpolation be? How do we validate the timing measurements? The preferred sampling rate would be as low as possible, considering the high cost and power consumption of high-speed analog-to-digital converters. However, when the sampling rate is too low, due to the aliasing effect, some artifacts are produced in the timing resolution estimations; the shape of the timing profile is distorted and the FWHM values of the profile fluctuate as the source location changes. Anti-aliasing filters are required in this case to avoid the artifacts, but the timing is degraded as a result. When the sampling rate is marginally over the Nyquist rate, a proper signal interpolation is important. A sharp roll-off (higher order) filter is required to separate the baseband signal from its replicates to avoid the aliasing, but in return the computation will be higher. We demonstrated the analysis through a digital timing study using fast LSO scintillation crystals as used in time-of-flight PET scanners. From the study, we observed that there is no significant timing resolution degradation down to 1.3 Ghz sampling frequency, and the computation requirement for the signal interpolation is reasonably low. A so-called sliding test is proposed as a validation tool checking constant timing resolution behavior of a given timing pick-off method regardless of the source location change. Lastly, the performance comparison for several digital timing methods is also shown.

  16. Bioaerosol DNA Extraction Technique from Air Filters Collected from Marine and Freshwater Locations

    Science.gov (United States)

    Beckwith, M.; Crandall, S. G.; Barnes, A.; Paytan, A.

    2015-12-01

    Bioaerosols are composed of microorganisms suspended in air. Among these organisms include bacteria, fungi, virus, and protists. Microbes introduced into the atmosphere can drift, primarily by wind, into natural environments different from their point of origin. Although bioaerosols can impact atmospheric dynamics as well as the ecology and biogeochemistry of terrestrial systems, very little is known about the composition of bioaerosols collected from marine and freshwater environments. The first step to determine composition of airborne microbes is to successfully extract environmental DNA from air filters. We asked 1) can DNA be extracted from quartz (SiO2) air filters? and 2) how can we optimize the DNA yield for downstream metagenomic sequencing? Aerosol filters were collected and archived on a weekly basis from aquatic sites (USA, Bermuda, Israel) over the course of 10 years. We successfully extracted DNA from a subsample of ~ 20 filters. We modified a DNA extraction protocol (Qiagen) by adding a beadbeating step to mechanically shear cell walls in order to optimize our DNA product. We quantified our DNA yield using a spectrophotometer (Nanodrop 1000). Results indicate that DNA can indeed be extracted from quartz filters. The additional beadbeating step helped increase our yield - up to twice as much DNA product was obtained compared to when this step was omitted. Moreover, bioaerosol DNA content does vary across time. For instance, the DNA extracted from filters from Lake Tahoe, USA collected near the end of June decreased from 9.9 ng/μL in 2007 to 3.8 ng/μL in 2008. Further next-generation sequencing analysis of our extracted DNA will be performed to determine the composition of these microbes. We will also model the meteorological and chemical factors that are good predictors for microbial composition for our samples over time and space.

  17. Acaroid mite allergens from the filters of air-conditioning system in China.

    Science.gov (United States)

    Li, Chao-Pin; Guo, Wei; Zhan, Xiao-Dong; Zhao, Bei-Bei; Diao, Ji-Dong; Li, Na; He, Lian-Ping

    2014-01-01

    Accumulation of acaroid mites in the filters of air-conditioners is harmful to human health. It is important to clarify the allergen components of mites from the filters of local air-conditioning system. The present study was to detect the allergen types in the filters of air-conditioners and assesse their allergenicity by asthmatic models. Sixty aliquots of dust samples were collected from air conditioning filters in civil houses in Wuhu area. Total protein was extracted from the dust samples using PBS and quantified by Bradford method. Allergens I and II were also detected by Western blot using primary antibody (anti-Der f1/2, Der p1/Der f2/Der p2, respectively). Ten aliquots of the positive samples were randomly selected for homogenization and sensitized the mice for developing asthmatic animal models. Total serum IgE level and IFN-γ, IL-4 and IL-5 in the bronchoalveolar lavage fluid (BALF). The allergenicity of the extraction was assessed using pathological sections developed from the mouse pulmonary tissues. The concentration of extract from the 60 samples was ranged from 4.37 μg/ml to 30.76 μg/ml. After analyzing with Western blot, 31 of 60 samples were positive for 4 allergens of acaroid mites, and yet 16 were negative. The levels of total IgE from serum IL-4 and IL-5 from the BALF in the experimental group were apparently higher than that of negative control and PBS group (P 0.05). However,the IFN-γ level in BALF was lower compared with the negative control and PBS group (P 0.05). The pathological changes were evidently emerged in pulmonary tissues, which were similar to those of OVA group, compared with the PBS ground and negative controls. The air-conditioner filters in human dwellings of Wuhu area potentially contain the major group allergen 1 and 2 from D. farinae and D. pteronyssinus, which may be associated with seasonal prevalence of allergic disorders in this area.

  18. Design and development of high performance panel air filter with experimental evaluation and analysis of filter media pleats

    Directory of Open Access Journals (Sweden)

    Sagar R. Patil

    2015-11-01

    Full Text Available In automobile vehicles mostly plastic molded panel filters used for the purpose of engine air filtration. Fibrous structured cellulose media were being used with different permeability’s according to requirement of rated air flow rate required for the engine. To optimize the filter pleat design of automotive panel air filter, it is important to study correlation of pressure drop, dust holding capacity & efficiency. The main role of a filter is to provide least pressure drop with high dust holding and efficiency. A channel made for the testing of different pleat designs. This research comprises of experimental design & evaluation of filter element with variable pleat depth and pleat density. This assessment offers the selection of pleat design according to the performance requirements.

  19. Resistance of HEPA filter separator materials to humid air--hydrogen fluoride--fluorine environments

    International Nuclear Information System (INIS)

    The U. S. Energy Research and Development Administration (ERDA) is interested in the development of a high-efficiency particulate air (HEPA) filter that is resistant to such corrosive reagents as hydrogen fluoride (HF) and fluorine (F2) in air environments of normal relative humidity (about 50% RH). Several types of separator materials are used in the fabrication of commercial filters. The basic types of separator materials are asbestos, Kraft paper, plastic, and aluminum. At the request of the ERDA Division of Operational Safety, the different types of separator materials have been evaluated for their resistance to corrosive attack by HF and F2. The separator materials were dynamically tested in the 4-stage multiunit tester located in the Oak Ridge Gaseous Diffusion Plant laboratories. This is the system previously used in the evaluation of the Herty Foundation filter paper samples. Concurrent with the testing of filter media for its resistance to HF and F2, another component of the completed filter, the separator, was tested. All samples were exposed to a constant air flow (50% RH) of 32 liters/min, at 1000F, containing 900 ppM HF and 300 ppM F2. Exposure periods varied from 2 to 1000 h; however, the longer exposures were made only on the stronger candidates. Test results show the plastic and aluminum separator materials to be superior to the other types in resistance to HF and F2. The asbestos separators disintegrated after a relatively short exposure time; the Kraft paper types were the next weakest. The Clear Plastic S was the best performer of the plastics tested

  20. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yang Seon, E-mail: rup2r@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul, 120-749 (Korea, Republic of); Yoon, Ki Young, E-mail: yky810921@yonsei.ac.kr [Exhaust Emission Engineering Team, Hyundai Motor Company, Hwaseong 445-706, Republic of Korea (Korea, Republic of); Park, Jae Hong, E-mail: cheap@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul, 120-749 (Korea, Republic of); Hwang, Jungho, E-mail: hwangjh@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul, 120-749 (Korea, Republic of)

    2011-01-15

    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: {yields}This study examined the effects of air ions generated by a carbon fiber ionizer on the inactivation of bioaerosols. {yields}When the ion exposure time and the ion generation concentration were increased, the antibacterial efficiency increased. {yields}The bioaerosols carried a significant number of negative electrical charges. {yields}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.

  2. Preliminary enviromagnetic comparison of the moss, lichen, and filter fabric bags to air pollution monitoring

    Directory of Open Access Journals (Sweden)

    Hanna Salo

    2014-08-01

    Full Text Available Air quality and anthropogenic air pollutants are usually investigated by passive biomonitoring which utilizes native species. Active biomonitoring, instead, refers to the use of transplants or bags in areas lacking native species. In Finland, the standardized moss bag technique SFS 5794 is commonly applied in active monitoring but there is still need for simpler and labor-saving sample material even on international scale. This article focuses on a preliminary comparison of the usability and collection efficiency of bags made of moss Sphagnum papillosum, lichen Hypogymnia physodes, and filter fabric (Filtrete™ in active biomonitoring of air pollutants around an industrial site in Harjavalta, SW Finland. The samples are analyzed with magnetic (i.e. magnetic susceptibility, isothermal remanent magnetization, hysteresis loop and hysteresis parameters methods highly suitable as a first-step tool for pollution studies. The results show that the highest magnetic susceptibility of each sample material is measured close to the industrial site. Furthermore, moss bags accumulate more magnetic material than lichen bags which, on the contrary, perform better at further distances. Filter fabric bags are tested only at 1 km sites indicating a good accumulation capability near the source. Pseudo-single-domain (PSD magnetite is identified as the main magnetic mineral in all sample materials and good correlations are found between different bag types. To conclude, all three materials effectively accumulate air pollutants and are suitable for air quality studies. The results of this article provide a base for later studies which are needed in order to fully determine a new, efficient, and easy sample material for active monitoring.

  3. Air Sampling Instruments for Evaluation of Atmospheric Contaminants. Fourth Edition.

    Science.gov (United States)

    American Conference of Governmental Industrial Hygienists, Cincinnati, OH.

    This text, a revision and extension of the first three editions, consists of papers discussing the basic considerations in sampling air for specific purposes, sampler calibration, systems components, sample collectors, and descriptions of air-sampling instruments. (BT)

  4. Sampling and Filtering in Photovoltaic System Performance Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Driesse, Anton [PV Performance Labs, Freiburg (Germany); Stein, Joshua S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photovoltaic and Distributed Systems Integration; Riley, Daniel M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photovoltaic and Distributed Systems Integration; Carmignani, Craig K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photovoltaic and Distributed Systems Integration

    2014-10-01

    The performance of photovoltaic systems must be monitored accurately to ensure profitable long-term operation. The most important signals to be measured—irradiance and temperature, as well as power, current and voltage on both DC and AC sides of the system—contain rapid fluctuations that are not observable by typical monitoring systems. Nevertheless these fluctuations can affect the accuracy of the data that are stored. This report closely examines the main signals in one operating PV system, which were recorded at 2000 samples per second. It analyzes the characteristics and causes of the rapid fluctuations that are found, such as line-frequency harmonics, perturbations from anti-islanding detection, MPPT searching action and others. The operation of PV monitoring systems is then simulated using a wide range of sampling intervals, archive intervals and filtering options to assess how these factors influence data accuracy. Finally several potential sources of error are discussed with real-world examples.

  5. NEUTRON ACTIVATION ANALYSIS FOR SIMULTANEOUS DETERMINATION OF TRACE ELEMENTS IN AMBIENT AIR COLLECTED ON GLASS-FIBER FILTERS

    Science.gov (United States)

    Arsenic with 25 other elements are simultaneously determined in ambient air samples collected on glass-fiber filter composites at 250 United States sites. The instrumental neutron activation analysis (NAA) technique combined with the power of a dedicated mini-computer resulted in...

  6. Penurunan Kandungan Zat Kapur dalam Air Tanah dengan Menggunakan Filter Media Zeolit Alam dan Pasir Aktif Menjadi Air Bersih

    OpenAIRE

    Qorry Nugrahayu; Alfan Purnomo

    2013-01-01

    Salah satu syarat yang harus terpenuhi dalam kualitas air minum dalam parameter kimia adalah kesadahan. Salah satu kesadahan adalah kesadahan kalsium atau yang lebih sering dikenal dengan air kapur. Pada umumnya air tanah atau air sumur mempunyai tingkat kesadahan yang tinggi. Masalah lain yang timbul dari air tanah adalah kandungan Fe dan Mn yang tinggi. Penelitian ini bertujuan untuk memperoleh komposisi media filter yang efektif dan efisien untuk mereduksi kesadahan Kalsium, Fe dan Mn dala...

  7. Long term performance of particulate air-filter in an office environment

    DEFF Research Database (Denmark)

    Afshari, Alireza; Iqbal, Ahsan; Bergsøe, Niels Christian

    2015-01-01

    The present article is based on initial findings of an ongoing study. The objective of present study is to analyse the long term performance of an air particulate filter with and without ionizer. To study the performance of the air filters, a test rig was built in the Danish Building Research Ins...

  8. Relative solubiolity in simulated biological fluids of PuO2 on air sampler filters

    International Nuclear Information System (INIS)

    An ultrafiltration method was developed to estimate the solubility of PuO2 on an air filter in simulated lung fluid (SLF), simulated gastric juice (SGJ), and in 1% DTPA. After a very rapid early appearance in the filtrate, both 238Pu and 239Pu showed similar rates of low ultrafilterability. The amount of 239Pu appearing during the first day of ultrafiltration was 10 times less in SLF than in SGJ or DTPA, although the amount of 238Pu was similar for the three solvents. The method used to estimate solubility requires only about 1000 dpm of plutonium alpha radiation per sample

  9. High-efficiency particulate air (HEPA) filter performance following service and radiation exposure

    International Nuclear Information System (INIS)

    Small HEPA filters were exposed to a 60Co source with a radiation strength of 3 x 107 rads per hour and then exposed to steam--air mixtures at several times filter design flow, followed by extended exposure to steam and air at reduced flow. Additional filters were exposed to air flow in a reactor confinement system and then similarly tested with steam--air mixture flows. The test data and calculated effects of filter pluggage with moisture on confinement system performance following potential reactor accidents are described. Gamma radiation exposure impaired the performance of new filters only slightly and temporarily improved performance of service aged filters. Normal confinement system service significantly impaired filter performance although not sufficiently to prevent adequate performance of the SRP confinement system following an unlikely reactor accident. Calculations based on measured filter pluggage indicate that during an accident air flow could be reduced approximately 50 percent with service-degraded HEPA filters present, or approximately 10 percent with new filters damaged by the radiation exposure. (U.S.)

  10. 40 CFR 53.57 - Test for filter temperature control during sampling and post-sampling periods.

    Science.gov (United States)

    2010-07-01

    ... (40 CFR part 50, appendix L, figure L-30) or equivalent adaptor to facilitate measurement of sampler... recommended. (6) Sample filter or filters, as specified in section 6 of 40 CFR part 50, appendix L. (d... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Test for filter temperature...

  11. Antimicrobial nanoparticle-coated electrostatic air filter with high filtration efficiency and low pressure drop.

    Science.gov (United States)

    Sim, Kyoung Mi; Park, Hyun-Seol; Bae, Gwi-Nam; Jung, Jae Hee

    2015-11-15

    In this study, we demonstrated an antimicrobial nanoparticle-coated electrostatic (ES) air filter. Antimicrobial natural-product Sophora flavescens nanoparticles were produced using an aerosol process, and were continuously deposited onto the surface of air filter media. For the electrostatic activation of the filter medium, a corona discharge electrification system was used before and after antimicrobial treatment of the filter. In the antimicrobial treatment process, the deposition efficiency of S. flavescens nanoparticles on the ES filter was ~12% higher than that on the pristine (Non-ES) filter. In the evaluation of filtration performance using test particles (a nanosized KCl aerosol and submicron-sized Staphylococcus epidermidis bioaerosol), the ES filter showed better filtration efficiency than the Non-ES filter. However, antimicrobial treatment with S. flavescens nanoparticles affected the filtration efficiency of the filter differently depending on the size of the test particles. While the filtration efficiency of the KCl nanoparticles was reduced on the ES filter after the antimicrobial treatment, the filtration efficiency was improved after the recharging process. In summary, we prepared an antimicrobial ES air filter with >99% antimicrobial activity, ~92.5% filtration efficiency (for a 300-nm KCl aerosol), and a ~0.8 mmAq pressure drop (at 13 cm/s). This study provides valuable information for the development of a hybrid air purification system that can serve various functions and be used in an indoor environment. PMID:26172593

  12. Comparison of concentrations of ions sampled on cellulose and teflon filters

    OpenAIRE

    Kořínková, Alena

    2012-01-01

    Determination of chloride, fluoride, nitrate, sulfate, oxalate and ammonium bounded to aerosol by sampling on cellulose filters is influenced by positive and negative interferences of gaseous pollutants. Interferences of gaseous pollutants during sampling of aerosols on teflon filters were eliminated by including of annular diffusion denuder in front of the filter.

  13. Assessment of the Revised 3410 Building Filtered Exhaust Stack Sampling Probe Location

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiao-Ying; Recknagle, Kurtis P.; Glissmeyer, John A.

    2013-12-01

    In order to support the air emissions permit for the 3410 Building, Pacific Northwest National Laboratory performed a series of tests in the exhaust air discharge from the reconfigured 3410 Building Filtered Exhaust Stack. The objective was to determine whether the location of the air sampling probe for emissions monitoring meets the applicable regulatory criteria governing such effluent monitoring systems. In particular, the capability of the air sampling probe location to meet the acceptance criteria of ANSI/HPS N13.1-2011 , Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities was determined. The qualification criteria for these types of stacks address 1) uniformity of air velocity, 2) sufficiently small flow angle with respect to the axis of the duct, 3) uniformity of tracer gas concentration, and 4) uniformity of tracer particle concentration. Testing was performed to conform to the quality requirements of NQA-1-2000. Fan configurations tested included all fan combinations of any two fans at a time. Most of the tests were conducted at the normal flow rate, while a small subset of tests was performed at a slightly higher flow rate achieved with the laboratory hood sashes fully open. The qualification criteria for an air monitoring probe location are taken from ANSI/HPS N13.1-2011 and are paraphrased as follows with key results summarized: 1. Angular Flow—The average air velocity angle must not deviate from the axis of the stack or duct by more than 20°. Our test results show that the mean angular flow angles at the center two-thirds of the ducts are smaller than 4.5% for all testing conditions. 2. Uniform Air Velocity—The acceptance criterion is that the COV of the air velocity must be ≤ 20% across the center two thirds of the area of the stack. Our results show that the COVs of the air velocity across the center two-thirds of the stack are smaller than 2.9% for all testing conditions. 3

  14. Radiological results for samples collected on paired glass- and cellulose-fiber filters at the Sandia complex, Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Shadel, Craig A. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2016-03-01

    Airborne particulates are collected at U.S. Department of Energy sites that exhibit radiological contamination on the soil surface to help assess the potential for wind to transport radionuclides from the contamination sites. Collecting these samples was originally accomplished by drawing air through a cellulose-fiber filter. These filters were replaced with glass-fiber filters in March 2011. Airborne particulates were collected side by side on the two filter materials between May 2013 and May 2014. Comparisons of the sample mass and the radioactivity determinations for the side-by-side samples were undertaken to determine if the change in the filter medium produced significant results. The differences in the results obtained using the two filter types were assessed visually by evaluating the time series and correlation plots and statistically by conducting a nonparametric matched-pair sign test. Generally, the glass-fiber filters collect larger samples of particulates and produce higher radioactivity values for the gross alpha, gross beta, and gamma spectroscopy analyses. However, the correlation between the radioanalytical results for the glass-fiber filters and the cellulose-fiber filters was not strong enough to generate a linear regression function to estimate the glass-fiber filter sample results from the cellulose-fiber filter sample results.

  15. NUMERICAL SIMULATION FOR AIR AND AIR-PM FLOW IN WALL FLOW DIESEL PARTICULATE FILTERS

    Institute of Scientific and Technical Information of China (English)

    Zhao Binjuan; Yuan Shouqi; Seizo Kato; Akira Nishimura

    2005-01-01

    Numerical simulations are performed both for the single airflow and air-PM two-phase flow in wall flow diesel particulate filters (DPF) for the first time. The calculation domain is divided into two regions. In the inlet and outlet flow channels, the simulations are performed for the steady and laminar flow; In the porous filtration walls, the calculation model for flow in porous media is used. The Lagrange two-phase flow model is used to calculate the air-PM flow in DPF, for the dispersed phase (PM), its flow tracks are obtained by the integrating of the Lagrange kinetic equation. The calculated velocity, pressure distribution and PM flow tracks in DPF are obtained, which exhibits the main flow characteristics in wall flow DPF and will be help for the optimal design and performance prediction of wall flow DPF.

  16. Influence of air flow rate and backwashing on the hydraulic behaviour of a submerged filter.

    Science.gov (United States)

    Cobos-Becerra, Yazmin Lucero; González-Martínez, Simón

    2013-01-01

    The aim of this study was to evaluate backwashing effects on the apparent porosity of the filter media and on the hydraulic behaviour of a pilot scale submerged filter, prior to biofilm colonization, under different hydraulic retention times, and different air flow rates. Tracer curves were analysed with two mathematical models for ideal and non-ideal flow (axial dispersion and Wolf and Resnick models). The filter media was lava stones sieved to 4.5 mm. Backwashing causes attrition of media particles, decreasing the void volume of the filter media and, consequently, the tracer flow is more uniform. The eroded media presented lower dead volumes (79% for the filter with aeration and 8% for the filter without aeration) compared with the new media (83% for the filter with aeration and 22% for the filter without aeration). The flow patterns of eroded and new media were different because the more regular shape of the particles decreases the void volume of the filter media. The dead volume is attributed, in the case of the filter with aeration, to the turbulence caused by the air bubbles that generate preferential channelling of the bulk liquid along the filter media, creating large zones of stagnant liquid and, for the filter without aeration, to the channels formed due to the irregular shaped media.

  17. Improvement on Filter Sampling and Fluorine Ion-Selective Electrode Analysis for the De-termination of the Fluoride in Ambient Air%滤膜氟离子选择电极法测定大气中氟化物的改进

    Institute of Scientific and Technical Information of China (English)

    乔晓平

    2015-01-01

    通过对国标方法中标准溶液系列的配制、样品滤膜处理方法进行研究,改进滤膜采样氟离子选择电极法测定大气中氟化物的实验方法,并利用改进方法对大气样品和氟化物标准样品进行对比实验。结果表明,标准样品的标准偏差为0.010~0.019 mg/L,相对标准偏差为3.0%~3.2%;大气样品的标准偏差为0.058~0.12μg/m3,相对标准偏差为4.2%~4.5%,加标回收率在95%~105%之间,满足国家标准的要求。%By studying the national standard method in preparation of standard solutions and sample filter membrane processes,im-provements were made to the filter sampling and fluorine ion-selective electrode analysis for the determination of fluoride in ambient air.Comparisons were made between the atmospheric samples and the fluoride standard samples using the modified method.The re-sults showed that the standard deviation and relative standard deviation of the standard samples ranged between 0.010~0.019 mg/L and 3.0%~3.2%,respectively.The standard deviation and relative standard deviation of the atmospheric samples ranged between 0.058~0.12 μg/m3 and 4.2%~4.5%,respectively.In addition,the recovery rates ranged between 95% and 105%.All of them were consistent with the requirements of the national standard.

  18. Feasibility for the medium efficiency filter as a postfilter in the air cleaning unit

    International Nuclear Information System (INIS)

    The Air Cleaning Unit (ACU) is provided in a nuclear facility to filter the radioactive materials in gaseous effluents released from the facility during normal operation and during a postulated accident. The Air Cleaning Unit (ACU) consists of pre-HEPA filters, charcoal adsorber, post HEPA filters, fans, etc. The charcoal filters keep on-site dose and off-site effluents ALARA, consistent with regulatory requirements. The function of HEPA filter downstream of charcoal(carbon) adsorber in ACU is to catch potential radioactive carbon dust and to be a backup in the event of failure of upstream HEPA. Previous Regulatory Guide use only post HEPA filter of charcoal adsorber downstream but the Regulatory Guide of current revisions allows use of 95% dust spot efficiency filters in lieu of HEPA at the downstream of the carbon adsorber. In this paper is described that the background information of filters, Current Regulatory Guide of revised by the United States Nuclear Regulatory Commission and the feasibility for the medium efficiency filter as a carbon adsorber post filter in the Air Cleaning Unit

  19. Comparison of polycarbonate and cellulose acetate membrane filters for isolation of Campylobacter concisus from stool samples

    DEFF Research Database (Denmark)

    Linde Nielsen, Hans; Engberg, Jørgen; Ejlertsen, Tove;

    2013-01-01

    One thousand seven hundred ninety-one diarrheic stool samples were cultivated for Campylobacter spp. We found a high prevalence of Campylobacter concisus with use of a polycarbonate filter (n = 114) compared to a cellulose acetate filter (n = 79) (P ... to the commonly used cellulose acetate filter for detection of C. concisus....

  20. Solubility testing of actinides on breathing-zone and area air samples

    Energy Technology Data Exchange (ETDEWEB)

    Metzger, R.L.; Jessop, B.H.; McDowell, B.L. [Radiation Safety Engineering, Inc., Chandler, AZ (United States)

    1996-02-01

    A solubility testing method for several common actinides has been developed with sufficient sensitivity to allow profiles to be determined from routine breathing zone and area air samples in the workplace. Air samples are covered with a clean filter to form a filter-sample-filter sandwich which is immersed in an extracellular lung serum simulant solution. The sample is moved to a fresh beaker of the lung fluid simulant each day for one week, and then weekly until the end of the 28 day test period. The soak solutions are wet ashed with nitric acid and hydrogen peroxide to destroy the organic components of the lung simulant solution prior to extraction of the nuclides of interest directly into an extractive scintillator for subsequent counting on a Photon-Electron Rejecting Alpha Liquid Scintillation (PERALS{reg_sign}) spectrometer. Solvent extraction methods utilizing the extractive scintillators have been developed for the isotopes of uranium, plutonium, and curium. The procedures normally produce an isotopic recovery greater than 95% and have been used to develop solubility profiles from air samples with 40 pCi or less of U{sub 3}O{sub 8}. Profiles developed for U{sub 3}O{sub 8} samples show good agreement with in vitro and in vivo tests performed by other investigators on samples from the same uranium mills.

  1. ANALYSIS OF VAPORS FROM METHYLENE CHLORIDE EXTRACTS OF NUCLEAR GRADE HEPA FILTER FIBERGLASS SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    FRYE JM; ANASTOS HL; GUTIERREZ FC

    2012-06-07

    While several organic compounds were detected in the vapor samples used in the reenactment of the preparation of mounts from the extracts of nuclear grade high-efficiency particulate air filter fiberglass samples, the most significant species present in the samples were methylene chloride, phenol, phenol-d6, and 2-fluorophenol. These species were all known to be present in the extracts, but were expected to have evaporated during the preparation of the mounts, as the mounts appeared to be dry before any vapor was collected. These species were present at the following percentages of their respective occupational exposure limits: methylene chloride, 2%; phenol, 0.4%; and phenol-d6, 0.6%. However, there is no established limit for 2-fluorophenol. Several other compounds were detected at low levels for which, as in the case of 2-fluorophenol, there are no established permissible exposure limits. These compounds include 2-chlorophenol; N-nitroso-1-propanamine; 2-fluoro-1,1{prime}-biphenyl; 1,2-dihydroacenaphthylene; 2,5-cyclohexadiene-1,4-dione,2,6-bis(1,1-dimethylethyl); trimethyl oxirane; n-propylpropanamine; 2-(Propylamino)ethanol; 4-methoxy-1-butene; 6-methyl-5-hepten-2-one; and 3,4-dimethylpyridine. Some of these were among those added as surrogates or spike standards as part ofthe Advanced Technologies and Laboratories International, Inc. preparation ofthe extract of the HEPA filter media and are indicated as such in the data tables in Section 2, Results; other compounds found were not previously known to be present. The main inorganic species detected (sulfate, sodium, and sulfur) are also consistent with species added in the preparation of the methylene chloride extract of the high-efficiency particulate air sample.

  2. Modelling of air flows in pleated filters and of their clogging by solid particles

    International Nuclear Information System (INIS)

    The devices of air cleaning against particles are widely spread in various branches of industry: nuclear, motor, food, electronic,...; among these devices, numerous are constituted by pleated porous media to increase the surface of filtration and thus to reduce the pressure drop, for given air flow. The objective of our work is to compensate a lack evident of knowledge on the evolution of the pressure drop of pleated filter during the clogging and to deduct a modelling from it, on the basis of experiments concerning industrial filters of nuclear and car types. The obtained model is a function of characteristics of the filtering medium and pleats, of the characteristics of solid particles deposited on the filter, of the mass of particles and of the aeraulic conditions of air flow. It also depends on data on the clogging of flat filters of equivalent medium. To elaborate this model of pressure drop, an initial stage was carried out in order to characterize, experimentally and numerically, the pressure drop and the distribution of air flow in clean pleated filters of nuclear (high efficiency particulate air filter, in fiberglasses) and car (mean efficiency filter, in fibers of cellulose) types. The numerical model allowed to understand the fundamental role played by the aeraulic resistance of the filtering medium. From an non-dimensional approach, we established a semi-empirical model of pressure drop for a clean pleated filter valid for both studied types of medium; this model is used of first base for the development of the final model of clogging. The study of the clogging of the filters showed the complexity of the phenomenon dependent mainly on a reduction of the surface of filtration. This observation brings us to propose a clogging of pleated filters in three phases. Both first phases are similar in those observed for flat filters, while last phase corresponds to a reduction of the surface of filtration and leads a strong increase of the filter pressure drop

  3. Evaluation of Urban Air Quality By Passive Sampling Technique

    Science.gov (United States)

    Nunes, T. V.; Miranda, A. I.; Duarte, S.; Lima, M. J.

    Aveiro is a flat small city in the centre of Portugal, close to the Atlantic coast. In the last two decades an intensive development of demographic, traffic and industry growth in the region was observed which was reflected on the air quality degrada- tion. In order to evaluate the urban air quality in Aveiro, a field-monitoring network by passive sampling with high space resolution was implemented. Twenty-four field places were distributed in a area of 3x3 Km2 and ozone and NO2 concentrations were measured. The site distribution density was higher in the centre, 250x250 m2 than in periphery where a 500x500 m2 grid was used. The selection of field places took into consideration the choice criteria recommendation by United Kingdom environmental authorities, and three tubes and a blank tube for each pollutant were used at each site. The sampling system was mounted at 3m from the ground usually profiting the street lampposts. Concerning NO2 acrylic tubes were used with 85 mm of length and an in- ternal diameter of 12mm, where in one of the extremities three steel grids impregnated with a solution of TEA were placed and fixed with a polyethylene end cup (Heal et al., 1999); PFA Teflon tube with 53 mm of length and 9 mm of internal diameter and three impregnated glass filters impregnated with DPE solution fixed by a teflon end cup was used for ozone sampling (Monn and Hargartner, 1990). The passive sampling method for ozone and nitrogen dioxide was compared with continuous measurements, but the amount of measurements wasnSt enough for an accurate calibration and validation of the method. Although this constraint the field observations (June to August 2001) for these two pollutants assign interesting information about the air quality in the urban area. A krigger method of interpolation (Surfer- Golden Software-2000) was applied to field data to obtain isolines distribution of NO2 and ozone concentration for the studied area. Even the used passive sampling method has many

  4. Experimental Investigations on Electrospun Mat Production: For Use in High-Performance Air Filters

    OpenAIRE

    SOMAYEH FARHANG DEHGHAN; FARIDEH GOLBAAEI; BOZORGMEHR MADDAH; RASOUL YARAHMADI; ASGHAR SEDIGH ZADEH

    2015-01-01

    Electrospun nanofibrous filter media have attracted considerable attention in the last decade. The present study aimed to develop the electrospun PAN (polyacrylonitrile) filter media through experimental investigations for application in high-performance air filters. For this purpose, an experimental design was proposed to assess the effect of electrospinning process conditions including solution concentration, electric voltage and nozzle-collector distance on the structural properties of fil...

  5. AFA and AFAS analytical filter packets for studying radioactive iodine component composition in air medium

    International Nuclear Information System (INIS)

    To analyse radioactive iodine content in gaseous effluents air the AFAS-I and AFAS-SKI filter packets are used. It is shown that, when trapping molecular 131I vapors, very sharp sorption wave front is formed. Difficulty sorbed iodine fraction in the AFAS-I filter packet forms a gently sloping sorption wave front, which slope slightly varies in time. In the AFAS-SKI filter packet quick sorbent saturation takes place, sorption wave front is extended along the layer

  6. Realistic Air Filter Media Performance Simulation. Part I: Navier-Stokes / Finite-Volume CFD Procedures

    OpenAIRE

    Tronville, Paolo Maria

    2013-01-01

    A review of published studies of numerical techniques for air filter performance simulation shows that there are two general approaches to such simulations. One describes gases flowing through filter media as continuous fluids, influenced by themacro properties viscosity, density, and pressure. The alternate approach treats gases as molecules in random motion, impacting their own kind and solid surfaces on a micro-scale. The appropriate form for a given filter medium and operating condition d...

  7. Energy Efficient Indoor VOC Air Cleaning with Activated Carbon Fiber (ACF) Filters

    OpenAIRE

    Sidheswaran, Meera

    2012-01-01

    This study explores the potential environmental and energy benefits of using activated carbon fiber (ACF) filters for air cleaning in HVAC systems. The parallel aims for the air cleaning system were to enable reduced indoor exposures to volatile organic compounds (VOCs) and to simultaneously allow reduced rates and energy consumption for outdoor-air ventilation. We evaluated the use of ACF media to adsorb VOCs from indoor air during repeated simulated 12-hour to 24-hour periods of occupancy. ...

  8. Characterization of depth filter media for gas turbine intake air filtration: From flat sheet media to cartridge filter assembly

    International Nuclear Information System (INIS)

    Depth filter media should be able to contain a certain amount of dust within the barrier layer without excessive contribution to pressure drop increase and have acceptable particulate collection efficiency during a certain period of service. To satisfy all these preconditions, a depth filter media consisting of more than one layer is considered to be an appropriate structure. Three samples of the filter media of multiple-layer structure are designed and manufactured. Also samples of cartridge assembly were made for each media. The tests with flat sheet media were conducted using the standard test units. Test with cartridges were conducted in a recently developed test unit which can accommodate one single cartridge inside its chamber. Tests with filter media TFM2 and TFM3 missed at least one of the above mentioned targets. Based on the results from the tests with two previous media, the depth filter media TFM4 was developed to achieve greater holding capacity but did not exhibit satisfactory results. The shortcomings of three previously developed filter media were remedied by combining the advantages in a modified media TFM5 which, according to the test results, could be a good match for an efficient depth filtration media. The tests with flat sheet media and cartridge with pleated filter media TFM5 have shown satisfactory filtration performance with low initial pressure drop, high dust holding capacity and high particulate collection efficiency. (author)

  9. The influence of typical ways of operating and air-handling unit on the sensory pollution load from used bag filters

    DEFF Research Database (Denmark)

    Mysen, M.; Clausen, Geo; Bekö, Gabriel;

    2003-01-01

    An experiment was performed to determine whether the sensory pollution emitted from a bag filter that had been used for 3 months in a suburban area in Denmark was influenced by different ways of operating the air-handling unit (AHU). Samples of the used filter were pre-conditioned to simulate three...... operating conditions: 1) switched off overnight; 2) airflow reduced to 10% overnight; and 3) continuous 100% operation. Outside air passed through the samples and the acceptability of the air after the filter was assessed by a panel of subjects. The results indicate that turning off the AHU or reducing...... the airflow outside working hours would significantly increase the sensory pollution emitted by a used bag filter immediately after the AHU is turned on, in comparison with continuous airflow through the AHU (P...

  10. Ultrafine particle removal by residential heating, ventilating, and air-conditioning filters.

    Science.gov (United States)

    Stephens, B; Siegel, J A

    2013-12-01

    This work uses an in situ filter test method to measure the size-resolved removal efficiency of indoor-generated ultrafine particles (approximately 7-100 nm) for six new commercially available filters installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC filters were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel filters (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media filters (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine particles (UFP) sizes with the lowest rated filters (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated filter (MERV 16). The deeper bed filters generally achieved higher removal efficiencies than the panel filters, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new filters and other inputs from real buildings shows that MERV 13-16 filters could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency filters, depending in part on particle size.

  11. Backflushing Filters for Field Processing of Water Samples Prior to Trace-Element Analyses

    Science.gov (United States)

    Kennedy, V.C.; Jenne, E.A.; Burchard, J.M.

    1976-01-01

    A portable unit is described for filtering water samples at field sites in such a manner that the filtrate is suitable for analysis not only of major constituents but also of trace elments at the mocrogram-per-liter level. A battery-operated peristaltic pump forces the water sample through medical-grade silicone tubing into and through an all-plastic in-line filter which can be backflushed when sediment clogs the filter membrane. Initial filtration rate exceeds 500 milliliter/minute and, because of the backflushing feature, a total time for filtering high-sediment-bearing waster samples is greatly reduced. (Woodard-USGS)

  12. Sampling strong tracking nonlinear unscented Kalman filter and its application in eye tracking

    International Nuclear Information System (INIS)

    The unscented Kalman filter is a developed well-known method for nonlinear motion estimation and tracking. However, the standard unscented Kalman filter has the inherent drawbacks, such as numerical instability and much more time spent on calculation in practical applications. In this paper, we present a novel sampling strong tracking nonlinear unscented Kalman filter, aiming to overcome the difficulty in nonlinear eye tracking. In the above proposed filter, the simplified unscented transform sampling strategy with n + 2 sigma points leads to the computational efficiency, and suboptimal fading factor of strong tracking filtering is introduced to improve robustness and accuracy of eye tracking. Compared with the related unscented Kalman filter for eye tracking, the proposed filter has potential advantages in robustness, convergence speed, and tracking accuracy. The final experimental results show the validity of our method for eye tracking under realistic conditions. (classical areas of phenomenology)

  13. HEPA filters of high structural strength for nuclear air cleaning systems

    International Nuclear Information System (INIS)

    HEPA-filter media, though having excellent particle-removal efficiencies, remain characterized as rather brittle, fragile, and weak materials. As a result, undesired structural damage, followed by significant losses in filtration efficiency, can easily occur in handling, transport, and even normal operation of filter units. In recent years, extensive investigations into the structural limits of HEPA filters in dry air and under extended exposure to high-humidity airflow have been carried out. In the course of this work, the failure modes and the underlying failure mechanisms were thoroughly studied. On the basis of the information obtained, considerable improvements in the structural strength of HEPA filters could be achieved. As verified by removal efficiency tests, differential pressures up to 56 kPA in dry air and 15 kPA after extended operation under fog conditions were proved to be sustainable without mechanical damage to the filter medium

  14. MATHEMATICAL MODELING AND INTENSIFICATION OF CONDENSATION GRAVITY FINE AIR FILTER OPERATION

    Directory of Open Access Journals (Sweden)

    V. V. Shitov

    2011-04-01

    Full Text Available Problem statement. A problem of mathematical modeling and intensification of operation of the flow thermal diffusion chamber of the condensation gravity filter as one of the most efficient air filter is solved.Results and conclusions. This paper presents an example of the practical application of the model of heat and mass exchange in the thermodiffusion chamber as the main operating element of condensation gravity filter for high-performance air purification due to the generation of supersaturation fields with controlled properties. A criterion for quantitative assessment of purification efficiency in the form of breakthrough function is developed. The typical results of numerical modeling of the operation of the condensation gravity-type filter are presented for the most common case in practice. The possibility of intensification of the filter operation either at the stage of use or at the stage of design is shown based on the proposed approach, obtained models, and calculations.

  15. Distribution and rate of microbial processes in ammonia-loaded air filter biofilm

    DEFF Research Database (Denmark)

    Juhler, Susanne; Nielsen, Lars Peter; Schramm, Andreas;

    2009-01-01

    The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH3 in ventilation air from pig farms. The filter biofilm...... was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter...... with heterotrophic bacteria for O2 and inhibition by the protonated form of NO2-, HNO2. Product inhibition of AOB growth could explain why this type of filter tends to emit air with a rather constant NH3 concentration irrespective of variations in inlet concentration and airflow....

  16. Performances of pleated HEPA filters as a function of relative humidity of air

    International Nuclear Information System (INIS)

    Pleated High Efficiency Particulate Air (HEPA) filters are used for maintaining the containment of radioactive substances in nuclear plants; thus, they are sensitive elements of nuclear safety. Some accidental situations, such as the emergence of a hole on a pipe with release of steam, can lead to a high increase of the air humidity. This work can overcome the lack of analytical data in the literature regarding the behaviour of pleated HEPA filters, in terms of changes in pressure drop and efficiency, in presence of humidity (unsaturated air). Experimental clogging tests have been performed on a test bench with two aerosols: non hygroscopic micron-size alumina particles and hygroscopic sub-micron sodium chloride particles. The results showed that the influence of humidity during the clogging of a HEPA filter depends on several parameters: the geometry of the filter (plane or pleated), the size distribution and hygroscopicity of the aerosol clogging and finally the interaction time between the aerosol and humid air. Measurements of efficiency of clean and clogged filters (at different degrees of clogging), performed with the normalized soda fluorescein aerosol, are also sensitive to the presence of more or less relative humidity in the air. Finally, all results helped to develop an empirical model for estimating the evolution of the pressure drop of HEPA filters; this model is applicable during the formation of the particulate cake in presence of humidity without reducing of the surface area filtration. (author)

  17. VHF/UHF filters and multicouplers application of air resonators

    CERN Document Server

    Piette, Bernard

    2013-01-01

    This book describes the various devices used in radio communication and broadcasting to achieve high selectivity filtering and coupling. After providing a background in the basics of microwave theory and more detailed material - including a special chapter on precision and errors in measurement - the reader will find detailed descriptions, manufacturing processes, and, for the most useful instances, a number of worked-through formulas, which will allow engineers and technicians to design circuits or components for filtering or coupling applications. Content is covered in this format across a b

  18. Performance Analysis of Upsample Filter for Sample Rate Converter

    OpenAIRE

    Manish Sabraj,; Vipan Kakkar

    2012-01-01

    Now a days many signal processing tasks are performed in the digital domain. Various sample rates are used on the basis of required signal quality and the available bandwidth. Sample-rate conversion is therefore inevitable to interface systems with different sample rates. The aim of digital sample rate conversion is to bring a digital audio signal from one sample frequency to another. Some information is lost while sampling.The distortion of the audio signal introduced by the sample rat...

  19. In-situ continuous scanning high efficiency particulate air (HEPA) filter monitoring system

    International Nuclear Information System (INIS)

    The testing and replacement of HEPA filters, which are widely used in the nuclear industry to purify process air before it is ventilated to the atmosphere, is a costly and labor-intensive undertaking. Current methods of testing filter performance, such as differential pressure measurement and scanning air monitoring, allow for determination of overall filter performance but preclude detection of symptoms of incipient filter failure, such as small holes in the filters themselves. Using current technology, a continual in-situ monitoring system has been designed which provides three major improvements over current methods of filter testing and replacement. This system (1) realizes a cost savings by reducing the number of intact filters which are currently being replaced unnecessarily, (2) provides a more accurate and quantitative measurement of filter performance than is currently achieved with existing testing methods, and (3) reduces personnel exposure to a radioactive environment by automatically performing most testing operations. The operation and performance of the HEPA filter monitoring system are discussed

  20. Conditions for using outdoor-air inlet filter for removing UFP in residential buildings

    DEFF Research Database (Denmark)

    Afshari, Alireza; Ardkapan, Siamak Rahimi; Bergsøe, Niels Christian;

    2012-01-01

    The purpose of this project is to study the possibility of achieving a reduction of ultrafine particles in the indoor air by placing a filter at the outdoor-air inlet in residential buildings with exhaust ventilation or natural ventilation. This paper presents field measurements of airflow rates ...

  1. Next Generation Sequencing of Pooled Samples: Guideline for Variants’ Filtering

    Science.gov (United States)

    Anand, Santosh; Mangano, Eleonora; Barizzone, Nadia; Bordoni, Roberta; Sorosina, Melissa; Clarelli, Ferdinando; Corrado, Lucia; Martinelli Boneschi, Filippo; D’Alfonso, Sandra; De Bellis, Gianluca

    2016-01-01

    Sequencing large number of individuals, which is often needed for population genetics studies, is still economically challenging despite falling costs of Next Generation Sequencing (NGS). Pool-seq is an alternative cost- and time-effective option in which DNA from several individuals is pooled for sequencing. However, pooling of DNA creates new problems and challenges for accurate variant call and allele frequency (AF) estimation. In particular, sequencing errors confound with the alleles present at low frequency in the pools possibly giving rise to false positive variants. We sequenced 996 individuals in 83 pools (12 individuals/pool) in a targeted re-sequencing experiment. We show that Pool-seq AFs are robust and reliable by comparing them with public variant databases and in-house SNP-genotyping data of individual subjects of pools. Furthermore, we propose a simple filtering guideline for the removal of spurious variants based on the Kolmogorov-Smirnov statistical test. We experimentally validated our filters by comparing Pool-seq to individual sequencing data showing that the filters remove most of the false variants while retaining majority of true variants. The proposed guideline is fairly generic in nature and could be easily applied in other Pool-seq experiments. PMID:27670852

  2. Fungal colonization of air filters and insulation in a multi-story office building: production of volatile organics

    Science.gov (United States)

    Ahearn, D. G.; Crow, S. A.; Simmons, R. B.; Price, D. L.; Mishra, S. K.; Pierson, D. L.

    1997-01-01

    Secondary air filters in the air-handling units on four floors of a multi-story office building with a history of fungal colonization of insulation within the air distribution system were examined for the presence of growing fungi and production of volatile organic compounds. Fungal mycelium and conidia of Cladosporium and Penicillium spp. were observed on insulation from all floors and both sides of the air filters from one floor. Lower concentrations of volatile organics were released from air filter medium colonized with fungi as compared with noncolonized filter medium. However, the volatiles from the colonized filter medium included fungal metabolites such as acetone and a carbonyl sulfide-like compound that were not released from noncolonized filter medium. The growth of fungi in air distribution systems may affect the content of volatile organics in indoor air.

  3. Development of Air Sampling Technology by the Atomic Energy Research Establishment, Harwell

    International Nuclear Information System (INIS)

    For many years the Health Physics and Medical Division of the Atomic Energy Research Establishment, Harwell, has pursued a vigorous programme of investigation and development in the field of air-sampling technology. The programme has made important contributions to the development of sampling media, the design of sampling equipment, the characterization of environmental airborne contamination and the interpretation of air-sampling data in terms of personal exposure. These developments form the basis for the present operational and research programmes in this field in the United Kingdom Atomic Energy Authority (U.K.A.E.A). . This paper, which summarizes the advances made in the Harwell laboratories in the above fields, is divided into three sections: 1. Sampling techniques. The development and characterization of glass-fibre filter papers (Stevens and Hounam) with improved surface collection properties has simplified counting procedures and has made ' possible detailed autoradiographic examination of the dust collected. The problem of energy degradation of alpha radiation by absorption in particles and paper has been studied (Stevens and Toureau). Development of charcoal-impregnated papers (Stevens and Hounam) has facilitated the detection and measurement of airborne contamination by iodine vapour. The combination of these papers with granular characoal in the May Pack (May) has given a sampling device which is now in common use for the determination and characterization of atmospheric iodine contamination. The concept and development of the personal air sampler (Sherwood and Greenhalgh) led to a better appreciation of the uncertainties of conventional air sampling and to the first quantitative demonstration of the problems of interpreting air samples in terms of personal inhalation exposure. Work on the design of a size selective head for the personal air sampler has not yet resolved the difficulties. The drawbacks of the cascade impactor as a continuous size

  4. An intercomparison study of analytical methods used for quantification of levoglucosan in ambient aerosol filter samples

    Science.gov (United States)

    Yttri, K. E.; Schnelle-Kreis, J.; Maenhaut, W.; Abbaszade, G.; Alves, C.; Bjerke, A.; Bonnier, N.; Bossi, R.; Claeys, M.; Dye, C.; Evtyugina, M.; García-Gacio, D.; Hillamo, R.; Hoffer, A.; Hyder, M.; Iinuma, Y.; Jaffrezo, J.-L.; Kasper-Giebl, A.; Kiss, G.; López-Mahia, P. L.; Pio, C.; Piot, C.; Ramirez-Santa-Cruz, C.; Sciare, J.; Teinilä, K.; Vermeylen, R.; Vicente, A.; Zimmermann, R.

    2015-01-01

    The monosaccharide anhydrides (MAs) levoglucosan, galactosan and mannosan are products of incomplete combustion and pyrolysis of cellulose and hemicelluloses, and are found to be major constituents of biomass burning (BB) aerosol particles. Hence, ambient aerosol particle concentrations of levoglucosan are commonly used to study the influence of residential wood burning, agricultural waste burning and wildfire emissions on ambient air quality. A European-wide intercomparison on the analysis of the three monosaccharide anhydrides was conducted based on ambient aerosol quartz fiber filter samples collected at a Norwegian urban background site during winter. Thus, the samples' content of MAs is representative for BB particles originating from residential wood burning. The purpose of the intercomparison was to examine the comparability of the great diversity of analytical methods used for analysis of levoglucosan, mannosan and galactosan in ambient aerosol filter samples. Thirteen laboratories participated, of which three applied high-performance anion-exchange chromatography (HPAEC), four used high-performance liquid chromatography (HPLC) or ultra-performance liquid chromatography (UPLC) and six resorted to gas chromatography (GC). The analytical methods used were of such diversity that they should be considered as thirteen different analytical methods. All of the thirteen laboratories reported levels of levoglucosan, whereas nine reported data for mannosan and/or galactosan. Eight of the thirteen laboratories reported levels for all three isomers. The accuracy for levoglucosan, presented as the mean percentage error (PE) for each participating laboratory, varied from -63 to 20%; however, for 62% of the laboratories the mean PE was within ±10%, and for 85% the mean PE was within ±20%. For mannosan, the corresponding range was -60 to 69%, but as for levoglucosan, the range was substantially smaller for a subselection of the laboratories; i.e. for 33% of the

  5. An intercomparison study of analytical methods used for quantification of levoglucosan in ambient aerosol filter samples

    Science.gov (United States)

    Yttri, K. E.; Schnelle-Kreiss, J.; Maenhaut, W.; Alves, C.; Bossi, R.; Bjerke, A.; Claeys, M.; Dye, C.; Evtyugina, M.; García-Gacio, D.; Gülcin, A.; Hillamo, R.; Hoffer, A.; Hyder, M.; Iinuma, Y.; Jaffrezo, J.-L.; Kasper-Giebl, A.; Kiss, G.; López-Mahia, P. L.; Pio, C.; Piot, C.; Ramirez-Santa-Cruz, C.; Sciare, J.; Teinilä, K.; Vermeylen, R.; Vicente, A.; Zimmermann, R.

    2014-07-01

    The monosaccharide anhydrides (MAs) levoglucosan, galactosan and mannosan are products of incomplete combustion and pyrolysis of cellulose and hemicelluloses, and are found to be major constituents of biomass burning aerosol particles. Hence, ambient aerosol particle concentrations of levoglucosan are commonly used to study the influence of residential wood burning, agricultural waste burning and wild fire emissions on ambient air quality. A European-wide intercomparison on the analysis of the three monosaccharide anhydrides was conducted based on ambient aerosol quartz fiber filter samples collected at a Norwegian urban background site during winter. Thus, the samples' content of MAs is representative for biomass burning particles originating from residential wood burning. The purpose of the intercomparison was to examine the comparability of the great diversity of analytical methods used for analysis of levoglucosan, mannosan and galactosan in ambient aerosol filter samples. Thirteen laboratories participated, of which three applied High-Performance Anion-Exchange Chromatography (HPAEC), four used High-Performance Liquid Chromatography (HPLC) or Ultra-Performance Liquid Chromatography (UPLC), and six resorted to Gas Chromatography (GC). The analytical methods used were of such diversity that they should be considered as thirteen different analytical methods. All of the thirteen laboratories reported levels of levoglucosan, whereas nine reported data for mannosan and/or galactosan. Eight of the thirteen laboratories reported levels for all three isomers. The accuracy for levoglucosan, presented as the mean percentage error (PE) for each participating laboratory, varied from -63 to 23%; however, for 62% of the laboratories the mean PE was within ±10%, and for 85% the mean PE was within ±20%. For mannosan, the corresponding range was -60 to 69%, but as for levoglucosan, the range was substantially smaller for a subselection of the laboratories; i.e., for 33% of

  6. An intercomparison study of analytical methods used for quantification of levoglucosan in ambient aerosol filter samples

    Directory of Open Access Journals (Sweden)

    K. E. Yttri

    2014-07-01

    Full Text Available The monosaccharide anhydrides (MAs levoglucosan, galactosan and mannosan are products of incomplete combustion and pyrolysis of cellulose and hemicelluloses, and are found to be major constituents of biomass burning aerosol particles. Hence, ambient aerosol particle concentrations of levoglucosan are commonly used to study the influence of residential wood burning, agricultural waste burning and wild fire emissions on ambient air quality. A European-wide intercomparison on the analysis of the three monosaccharide anhydrides was conducted based on ambient aerosol quartz fiber filter samples collected at a Norwegian urban background site during winter. Thus, the samples' content of MAs is representative for biomass burning particles originating from residential wood burning. The purpose of the intercomparison was to examine the comparability of the great diversity of analytical methods used for analysis of levoglucosan, mannosan and galactosan in ambient aerosol filter samples. Thirteen laboratories participated, of which three applied High-Performance Anion-Exchange Chromatography (HPAEC, four used High-Performance Liquid Chromatography (HPLC or Ultra-Performance Liquid Chromatography (UPLC, and six resorted to Gas Chromatography (GC. The analytical methods used were of such diversity that they should be considered as thirteen different analytical methods. All of the thirteen laboratories reported levels of levoglucosan, whereas nine reported data for mannosan and/or galactosan. Eight of the thirteen laboratories reported levels for all three isomers. The accuracy for levoglucosan, presented as the mean percentage error (PE for each participating laboratory, varied from −63 to 23%; however, for 62% of the laboratories the mean PE was within ±10%, and for 85% the mean PE was within ±20%. For mannosan, the corresponding range was −60 to 69%, but as for levoglucosan, the range was substantially smaller for a subselection of the laboratories; i

  7. Farrow-structure-based reconfigurable bandpass linear-phase FIR filters for integer sampling rate conversion

    OpenAIRE

    Johansson, Håkan

    2011-01-01

    A class of Farrow-structure-based reconfigurable bandpass finite-length impulse response (FIR) filters for integer sampling rate conversion is introduced. The converters are realized in terms of a number of fixed linear-phase FIR subfilters and two sets of reconfigurable multipliers that determine the passband location and conversion factor, respectively. Both Mth-band and general FIR filters can be realized, and the filters work equally well for any integer factor and passband location. Desi...

  8. CFD simulation of nanofiber-enhanced air filter media

    OpenAIRE

    Tronville, Paolo Maria

    2015-01-01

    The first step in a CFD analysis of filter media flow is to create a computational domain geometry which imitates the simulated media as closely as is practical. The media in the present study combined a relatively flat web of nanofibers with a cellulosic fiber support media. A CFD grid suited to calculating the flow patterns through the cellulosic media structure would be far too coarse to simulate flow around the nanofiber web elements. This scale difference forces some assumption about the...

  9. Flexible Analog Front Ends of Reconfigurable Radios Based on Sampling and Reconstruction with Internal Filtering

    Directory of Open Access Journals (Sweden)

    Poberezhskiy Gennady Y

    2005-01-01

    Full Text Available Bandpass sampling, reconstruction, and antialiasing filtering in analog front ends potentially provide the best performance of software defined radios. However, conventional techniques used for these procedures limit reconfigurability and adaptivity of the radios, complicate integrated circuit implementation, and preclude achieving potential performance. Novel sampling and reconstruction techniques with internal filtering eliminate these drawbacks and provide many additional advantages. Several ways to overcome the challenges of practical realization and implementation of these techniques are proposed and analyzed. The impact of sampling and reconstruction with internal filtering on the analog front end architectures and capabilities of software defined radios is discussed.

  10. Thoron (220Rn) progeny reduction by an air cleaner of the polarized media filter type

    International Nuclear Information System (INIS)

    The effect of an air cleaner on 220Rn progeny atmospheres has been studied in a Radon/Thoron Test Facility (RTTF) of the walk-in type. The air cleaner consists basically of a fan and a special filter material sandwiched between two metal screens, to which an electric field is applied. The filter is of the polarized media type and uses fibreglass as material. The fan and filter system are housed in a metal case. Air is drawn from the back of the case by means of the fan and forced through the 'electrical' filter where removal of the 220Rn progeny occurs. Radon-220 progeny 'depleted' air is discharged at the top of the device. Tests were conducted in 220Rn/220Rn progeny atmospheres when the air cleaner was operating, and when it was turned off. Very pronounced effects were observed during the operation of the device, namely: a dramatic decrease in the 220Rn progeny concentrations and the total aerosol concentration, as well as a large increase in the 220Rn progeny unattached fractions and the plate-out of these radionuclides on the walls of the RTTF. The air cleaner has potential in industrial applications, which should be explored. (orig.)

  11. Depth profiling of hydrogen in amorphous media and applicable to quartz air filters

    International Nuclear Information System (INIS)

    We have explored the use of proton-proton coincidence, at proton energy of 6.35 MeV, for hydrogen determination and depth profiling in amorphous media. The method has been applied to quartz air filters. This non-destructive method is highly specific to hydrogen, depending only on the energy-loss distribution in p-p scattering events. The method, combined with other techniques, can be used to measure the total amount and depth distribution of particulate organic matter in aerosols on quartz air. The results for ambient air quartz filters show that the technique can separate several kinds of gaseous organic artifact, one of which cannot be corrected through the standard use of tandem quartz filters. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. Electrospinning Fabrication and Performance Evaluation of Polyacrylonitrile Nanofiber for Air Filter Applications

    Directory of Open Access Journals (Sweden)

    Nguyen Duy Vinh

    2016-08-01

    Full Text Available Nano materials possess unique mechanical, physical, and chemical properties. They are small, and have an ultrahigh surface area, making them suitable for air filter applications since air filtration is necessary to protect sensitive components from harmful particulates and gaseous contaminants. The electrospinning method has been recognized as an efficient technique for fabricating polymer nanofibers. In order to determine the optimum manufacturing conditions, the effects of several electrospinning process parameters on the diameter, orientation, and distribution of polyacrylonitrile (PAN nanofiber are analyzed. To improve interlaminar fracture toughness and suppress the delamination in the form of laminated non-woven fibers by using a heat roller, the performances of filter efficiency and pressure drop achieved with the PAN nanofiber air filter are evaluated experimentally.

  13. Development of a method for bacteria and virus recovery from heating, ventilation, and air conditioning (HVAC) filters.

    Science.gov (United States)

    Farnsworth, James E; Goyal, Sagar M; Kim, Seung Won; Kuehn, Thomas H; Raynor, Peter C; Ramakrishnan, M A; Anantharaman, Senthilvelan; Tang, Weihua

    2006-10-01

    The aim of the work presented here is to study the effectiveness of building air handling units (AHUs) in serving as high volume sampling devices for airborne bacteria and viruses. An HVAC test facility constructed according to ASHRAE Standard 52.2-1999 was used for the controlled loading of HVAC filter media with aerosolized bacteria and virus. Nonpathogenic Bacillus subtilis var. niger was chosen as a surrogate for Bacillus anthracis. Three animal viruses; transmissible gastroenteritis virus (TGEV), avian pneumovirus (APV), and fowlpox virus were chosen as surrogates for three human viruses; SARS coronavirus, respiratory syncytial virus, and smallpox virus; respectively. These bacteria and viruses were nebulized in separate tests and injected into the test duct of the test facility upstream of a MERV 14 filter. SKC Biosamplers upstream and downstream of the test filter served as reference samplers. The collection efficiency of the filter media was calculated to be 96.5 +/- 1.5% for B. subtilis, however no collection efficiency was measured for the viruses as no live virus was ever recovered from the downstream samplers. Filter samples were cut from the test filter and eluted by hand-shaking. An extraction efficiency of 105 +/- 19% was calculated for B. subtilis. The viruses were extracted at much lower efficiencies (0.7-20%). Our results indicate that the airborne concentration of spore-forming bacteria in building AHUs may be determined by analyzing the material collected on HVAC filter media, however culture-based analytical techniques are impractical for virus recovery. Molecular-based identification techniques such as PCR could be used.

  14. ALMERA Proficiency Test: Determination of Gamma Emitting Radionuclides in Simulated Air Filters

    International Nuclear Information System (INIS)

    The activity concentration of radionuclides in air is a critical factor in assessing the air quality and the potential impact of possible pollutants. Air is in fact one of the main pathways for human exposure to radioactivity. Radioactivity may be present in the atmosphere due to natural processes; intentional (low level) anthropogenic release; or as a consequence of nuclear or radiological incident. The resulting environmental impact should be considered carefully to ensure safety and compliance with environmental regulations. A reliable determination of radionuclides in air is necessary for regular monitoring of air quality to comply with radiation protection and environmental regulations. This proficiency test (PT) is one of the series of the ALMERA network proficiency tests organised on regular basis by the Terrestrial Environment Laboratory in Seibersdorf, designed to assess the technical capacity of ALMERA Members in analysing radionuclides to identify any analytical problems and to support ALMERA laboratories to maintain their preparedness to provide rapid and reliable analytical results. The range of simulated air filters used in this PT for analysis has been mainly at environmental level. The PT set consisted of four filters. The participating laboratories were requested to analyze Mn-54, Co-57, Fe-59, Co-60, Zn-65, Cd-109, Ba-133, Cs-134, Cs-137, Eu-152 and Am-241 in filters 01, 02 and 03. The participants were informed that only some of the listed radionuclides were present in the filters and the levels of the radionuclides were such that they could be measured within a 6-hour measurement period using a conventional HPGe gammaspectrometer of 35% relative efficiency. Filter 04, was containing only Co-60 and Ba-133 with known activities to the participants, had to be used as a control for the efficiency calibration. The tasks of IAEA were to prepare and distribute the simulated air filters to the participating laboratories, to collect and interpret

  15. Robust H-infinity filtering on uncertain systems under sampled measurements

    Institute of Scientific and Technical Information of China (English)

    Ping SUN; Yuanwei JING

    2006-01-01

    This paper is concerned with the problem of robust H-infinity filtering on uncertain systems under sampled measurements, both continuous disturbance and discrete disturbance are considered in the systems. The parameter uncertainty is assumed to be time-varying norm-bounded. The aim is to design an asymptotically stable filter, using the locally sampled measurements, which ensures both the robust asymptotic stability and a prescribed level of H-infinity performance for the filtering error dynamics for all admissible uncertainties. The derivation process is simplified by introducing auxiliary systems and the sufficient condition for the existence of such a filter is proposed. During the study, the main results were expressed as LMIs by employing various matrix techniques. Using LMI toolbox of Matlab software, it is very convenient to obtain the appropriate filter. Finally, a numerical example shows that the method is effective and feasible.

  16. Solid waste transuranic storage and assay facility indoor air sampling

    Energy Technology Data Exchange (ETDEWEB)

    Pingel, L.A., Westinghouse Hanford

    1996-08-20

    The purpose of the study is to collect and analyze samples of the indoor air at the Transuranic Storage and Assay Facility (TRUSAF), Westinghouse Hanford. A modified US EPA TO-14 methodology, using gas chromatography/mass spectrography, may be used for the collection and analysis of the samples. The information obtained will be used to estimate the total release of volatile organic compounds from TRUSAF to determine the need for air emmission permits.

  17. Presence of organophosphorus pesticide oxygen analogs in air samples

    OpenAIRE

    Armstrong, Jenna L.; Fenske, Richard A; Yost, Michael G.; Galvin, Kit; Tchong-French, Maria; Yu, Jianbo

    2013-01-01

    A number of recent toxicity studies have highlighted the increased potency of oxygen analogs (oxons) of several organophosphorus (OP) pesticides. These findings were a major concern after environmental oxons were identified in environmental samples from air and surfaces following agricultural spray applications in California and Washington State. This paper reports on the validity of oxygen analog measurements in air samples for the OP pesticide, chlorpyrifos. Controlled environmental and lab...

  18. Radioactive air emissions notice of construction for HEPA filtered vacuum radioactive air emission units

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.E.

    1997-10-27

    This notice of construction (NOC) requests a categorical approval for construction and operation of certain portable high-efficiency particulate air (HEPA) filtered vacuum radionuclide airborne emission units (HVUs). Approval of this NOC application is intended to allow operation of the HVUs without prior project-specific approval. This NOC does not request replacement or supersedence of any previous agreements/approvals by the Washington State Department of Health (WDOH) for the use of vacuums on the Hanford Site. These previous agreements/approvals include the approved NOCs for the use of EuroClean HEPA vacuums at the T Plant Complex and the Kelly Decontamination System at the Plutonium-Uranium Extraction (PUREX) Plant. Also, this NOC does not replace or supersede the agreement reached regarding the use of HEPA hand-held/shop-vacuum cleaners for routine cleanup activities conducted by the Environmental Restoration Project. Routine cleanup activities are conducted during the surveillance and maintenance of inactive waste sites (Radioactive Area Remedial Action Project) and inactive facilities. HEPA hand-held/shop-vacuum cleaners are used to clean up spot surface contamination areas found during outdoor radiological field surveys, and to clean up localized radiologically contaminated material (e.g., dust, dirt, bird droppings, animal feces, liquids, insects, spider webs, etc.). This agreement, documented in the October 12, 1994 Routine Meeting Minutes, is based on routine cleanup consisting of spot cleanup of low-level contamination provided that, in each case, the source term potential would be below 0.1 millirem per year. This application is intended to request sitewide approval for the new activities, and provide an option for any facility on the site to use this approval, within the terms of this NOC. The HVUs used in accordance with this NOC will support reduction of radiological contamination at various locations on the Hanford Site. Radiation Protection Air

  19. First report of Legionella pneumophila in car cabin air filters. Are these a potential exposure pathway for professional drivers?

    Science.gov (United States)

    Alexandropoulou, Ioanna G; Konstantinidis, Theocharis G; Parasidis, Theodoros A; Nikolaidis, Christos; Panopoulou, Maria; Constantinidis, Theodoros C

    2013-12-01

    Recent findings have identified professional drivers as being at an increased risk of Legionnaires' disease. Our hypothesis was that used car cabin air filters represent a reservoir of Legionella bacteria, and thus a potential pathway for contamination. We analysed used cabin air filters from various types of car. The filters were analysed by culture and by molecular methods. Our findings indicated that almost a third of air filters were colonized with Legionella pneumophila. Here, we present the first finding of Legionella spp. in used car cabin air filters. Further investigations are needed in order to confirm this exposure pathway. The presence of Legionella bacteria in used cabin air filters may have been an unknown source of infection until now. PMID:24099652

  20. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Science.gov (United States)

    2010-07-01

    ... the mean mass of each sample medium (e.g., filter). Use good engineering judgment to exclude outliers... the sample medium's mass. However, it may not be advantageous when net PM masses exceed 1% of the sample medium's mass. If you utilize substitution weighing, it must be used for both pre-test and...

  1. Looking for the minimum efficiency of fibrous air filters during their service life

    OpenAIRE

    Tronville, Paolo Maria

    2012-01-01

    Electret fibrous air filter media achieve high efficiencies while maintaining low air flow resistance by incorporating electrostatic charges on their fibers. However, captured ultrafine particles reduce this electrostatic enhancement. It is important to evaluate the behavior of such media when their electrostatic enhancement has been completely suppressed, leaving only "mechanical" effects such as sieving, impaction, interception and diffusion. Existing standards EN779:2002 and ASHRAE 52.2-20...

  2. Standard specification for high efficiency particulate air filters. Revision No. 2

    International Nuclear Information System (INIS)

    This specification covers the requirements for four types and four sizes of high efficiency particulate air filters, assembled with or without separators and gaskets. Types include Fire Resistant and Moisture Resistant; Hydrogen Fluoride Fume (HF) Resistant; Fire Resistant and Moisture Resistant and Chemical Resistant; and Fire Resistant and Moisture Resistant, High Temperature and High Humidity

  3. FLOW CHARACTERISTICS OF WALL-FLOW DIESEL PARTICULATE FILTER SYSTEM WITH REVERSE PULSE AIR REGENERATION

    Institute of Scientific and Technical Information of China (English)

    Yao Chunde; Shao Yuping; Zhang Chunrun; Zi XinYun; Jiang Dahai; Deng Chenglin

    2005-01-01

    To simulate steady airflows inside of wall-flow diesel particulate filters (DPF) with different reverse blowing pipes collocation, a mathematical model of the flow in a DPF is established by an equivalent continuum approach. The experimental results agree well with the theoretical values calculated from the model. Simulation shows that the velocity and the pressure distribution of the filters in the regenerative process are key factors to the filter's regeneration. How to decrease the mal-distribution of the flow in the filter and how to achieve the better regenerative performance at the least cost of air consumption in the regenerative process are the ultimate goals of the study. Calculation and experiments show that the goals can be realized through adjusting the angle of two reverse blowing pipes and their relative location suitably.

  4. Call-centre occupant response to new and used filters at two outdoor air supply rates

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Wyon, David; Nielsen, J.;

    2002-01-01

    A 2x2 replicaterd field intervention experiment was conducted in a call-centre providing a public telephone directory service: outdoor air supply rate was 8% or 80% of the total airflow of 430 L/s providing 3.5 h-1; and the supply air filters were either new or used (i.e. used in place for 6 mont......). Each of these 4 conditions was maintained for a full working week at a time. Room temperature and humidity averaged 24 deg.C and 27% RH. The 26 operators were blind to conditions and assessed perceived air quality (PAQ), the intensity of Sick Building Syndrome (SBS) symnptoms and self...

  5. Passive sampling of polychlorinated biphenyls (PCB) in indoor air

    DEFF Research Database (Denmark)

    Vorkamp, Katrin; Mayer, Philipp

    PCBs were widely used in construction materials in the 1906s and 1970s, a period of high building activity in Denmark. The objective of this study was therefore to use passive sampling techniques to develop a simple and cost-effective screening tool for PCBs in indoor air. The study proceeded...... in three phases combining a literature review, laboratory experiments and measurements in buildings potentially containing PCBs in indoor air. The laboratory experiments showed a strong influence of air velocity on the PCB partitioning between air and the passive sampler. Based on the results of the first...... two phases and comments from experts in the field of PCB containing construction materials, a kinetic sampler (petri dish with silicone) and a potential equilibrium sampler (silicone-coated paper) were tested in buildings. Calibration and validation were based on conventional active sampling, for both...

  6. THE REAL ISSUE WITH WALL DEPOSITS IN CLOSED FILTER CASSETTES - WHAT'S THE SAMPLE?

    Energy Technology Data Exchange (ETDEWEB)

    Brisson, M.

    2009-09-12

    The measurement of aerosol dusts has long been utilized to assess the exposure of workers to metals. Tools used to sample and measure aerosol dusts have gone through many transitions over the past century. In particular, there have been several different techniques used to sample for beryllium, not all of which might be expected to produce the same result. Today, beryllium samples are generally collected using filters housed in holders of several different designs, some of which are expected to produce a sample that mimics the human capacity for dust inhalation. The presence of dust on the interior walls of cassettes used to hold filters during metals sampling has been discussed in the literature for a number of metals, including beryllium, with widely varying data. It appears that even in the best designs, particulates can enter the sampling cassette and deposit on the interior walls rather than on the sampling medium. The causes are not well understood but are believed to include particle bounce, electrostatic forces, particle size, particle density, and airflow turbulence. Historically, the filter catch has been considered to be the sample, but the presence of wall deposits, and the potential that the filter catch is not representative of the exposure to the worker, puts that historical position into question. This leads to a fundamental question: What is the sample? This article reviews the background behind the issue, poses the above-mentioned question, and discusses options and a possible path forward for addressing that question.

  7. Effects of Temperature, Humidity and Air Flow on Fungal Growth Rate on Loaded Ventilation Filters.

    Science.gov (United States)

    Tang, W; Kuehn, T H; Simcik, Matt F

    2015-01-01

    This study compares the fungal growth ratio on loaded ventilation filters under various temperature, relative humidity (RH), and air flow conditions in a controlled laboratory setting. A new full-size commercial building ventilation filter was loaded with malt extract nutrients and conidia of Cladosporium sphaerospermum in an ASHRAE Standard 52.2 filter test facility. Small sections cut from this filter were incubated under the following conditions: constant room temperature and a high RH of 97%; sinusoidal temperature (with an amplitude of 10°C, an average of 23°C, and a period of 24 hr) and a mean RH of 97%; room temperature and step changes between 97% and 75% RH, 97% and 43% RH, and 97% and 11% RH every 12 hr. The biomass on the filter sections was measured using both an elution-culture method and by ergosterol assay immediately after loading and every 2 days up to 10 days after loading. Fungal growth was detected earlier using ergosterol content than with the elution-culture method. A student's t-test indicated that Cladosporium sphaerospermum grew better at the constant room temperature condition than at the sinusoidal temperature condition. By part-time exposure to dry environments, the fungal growth was reduced (75% and 43% RH) or even inhibited (11% RH). Additional loaded filters were installed in the wind tunnel at room temperature and an RH greater than 95% under one of two air flow test conditions: continuous air flow or air flow only 9 hr/day with a flow rate of 0.7 m(3)/s (filter media velocity 0.15 m/s). Swab tests and a tease mount method were used to detect fungal growth on the filters at day 0, 5, and 10. Fungal growth was detected for both test conditions, which indicates that when temperature and relative humidity are optimum, controlling the air flow alone cannot prevent fungal growth. In real applications where nutrients are less sufficient than in this laboratory study, fungal growth rate may be reduced under the same operating conditions.

  8. Background culturable bacteria aerosol in two large public buildings using HVAC filters as long term, passive, high-volume air samplers.

    Science.gov (United States)

    Stanley, Nicholas J; Kuehn, Thomas H; Kim, Seung Won; Raynor, Peter C; Anantharaman, Senthilvelan; Ramakrishnan, M A; Goyal, Sagar M

    2008-04-01

    Background culturable bacteria aerosols were collected and identified in two large public buildings located in Minneapolis, Minnesota and Seattle, Washington over a period of 5 months and 3 months, respectively. The installed particulate air filters in the ventilation systems were used as the aerosol sampling devices at each location. Both pre and final filters were collected from four air handing units at each site to determine the influence of location within the building, time of year, geographical location and difference between indoor and outdoor air. Sections of each loaded filter were eluted with 10 ml of phosphate buffered saline (PBS). The resulting solutions were cultured on blood agar plates and incubated for 24 h at 36 degrees C. Various types of growth media were then used for subculturing, followed by categorization using a BioLog MicroStation (Biolog, Hayward, CA, USA) and manual observation. Environmental parameters were gathered near each filter by the embedded on-site environmental monitoring systems to determine the effect of temperature, humidity and air flow. Thirty nine different species of bacteria were identified, 17 found only in Minneapolis and 5 only in Seattle. The hardy spore-forming genus Bacillus was the most commonly identified and showed the highest concentrations. A significant decrease in the number of species and their concentration occurred in the Minneapolis air handling unit supplying 100% outdoor air in winter, however no significant correlations between bacteria concentration and environmental parameters were found.

  9. Air Monitoring: New Advances in Sampling and Detection

    Directory of Open Access Journals (Sweden)

    Nicola Watson

    2011-01-01

    Full Text Available As the harmful effects of low-level exposure to hazardous organic air pollutants become more evident, there is constant pressure to improve the detection limits of indoor and ambient air monitoring methods, for example, by collecting larger air volumes and by optimising the sensitivity of the analytical detector. However, at the other end of the scale, rapid industrialisation in the developing world and growing pressure to reclaim derelict industrial land for house building is driving the need for air monitoring methods that can reliably accommodate very-high-concentration samples in potentially aggressive matrices. This paper investigates the potential of a combination of two powerful gas chromatography—based analytical enhancements—sample preconcentration/thermal desorption and time-of-flight mass spectrometry—to improve quantitative and qualitative measurement of very-low-(ppt level organic chemicals, even in the most complex air samples. It also describes new, practical monitoring options for addressing equally challenging high-concentration industrial samples.

  10. Antimicrobial durability of air filters coated with airborne Sophora flavescens nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chong, Eui-seok; Hwang, Gi Byoung [Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Nho, Chu Won [Functional Food Center, Korea Institute of Science and Technology (KIST Gangneung Institute), Gangneung, Gangwon-do 210-340 (Korea, Republic of); Kwon, Bo Mi [Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Jung Eun [Biosafety Research Team, National Institute of Environmental Research, Kyungseo-Dong, Seo-Gu, Incheon 404-170 (Korea, Republic of); Seo, SungChul [Department of Environmental Health, College of Medicine, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Bae, Gwi-Nam, E-mail: gnbae@kist.re.kr [Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Jung, Jae Hee, E-mail: jaehee@kist.re.kr [Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

    2013-02-01

    Airborne biological particles containing viruses, bacteria, and/or fungi can be toxic and cause infections and allergy symptoms. Recently, natural materials such as tea tree oil and Sophora flavescens have shown promising antimicrobial activity when applied as air filter media. Although many of these studies demonstrated excellent antimicrobial efficacy, only a few of them considered external environmental effects such as the surrounding humidity, temperature, and natural degradation of chemicals, all of which can affect the antimicrobial performance of these natural materials. In this study, we investigated the antimicrobial durability of air filters containing airborne nanoparticles from S. flavescens for 5 months. Antimicrobial tests and quantitative chemical analyses were performed every 30 days. Morphological changes in the nanoparticles were also evaluated by scanning electron microscopy. The major antimicrobial compounds remained stable and active for ∼ 90 days at room temperature. After about 90 days, the quantities of major antimicrobial compounds decreased noticeably with a consequent decrease in antimicrobial activity. These results are promising for the implementation of new technologies using natural antimicrobial products and provide useful information regarding the average life expectancy of antimicrobial filters using nanoparticles of S. flavescens. - Graphical abstract: Variations in (a) the concentrations of major antimicrobial chemical compounds on S. flavescens nanoparticle-coated filters: kurarinone, kuraridin, and sophoraflavanone-G and (b) the inactivation rate of antimicrobial filters as a function of time.

  11. DUS II SOIL GAS SAMPLING AND AIR INJECTION TEST RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Noonkester, J.; Jackson, D.; Jones, W.; Hyde, W.; Kohn, J.; Walker, R.

    2012-09-20

    Soil vapor extraction (SVE) and air injection well testing was performed at the Dynamic Underground Stripping (DUS) site located near the M-Area Settling Basin (referred to as DUS II in this report). The objective of this testing was to determine the effectiveness of continued operation of these systems. Steam injection ended on September 19, 2009 and since this time the extraction operations have utilized residual heat that is present in the subsurface. The well testing campaign began on June 5, 2012 and was completed on June 25, 2012. Thirty-two (32) SVE wells were purged for 24 hours or longer using the active soil vapor extraction (ASVE) system at the DUS II site. During each test five or more soil gas samples were collected from each well and analyzed for target volatile organic compounds (VOCs). The DUS II site is divided into four parcels (see Figure 1) and soil gas sample results show the majority of residual VOC contamination remains in Parcel 1 with lesser amounts in the other three parcels. Several VOCs, including tetrachloroethylene (PCE) and trichloroethylene (TCE), were detected. PCE was the major VOC with lesser amounts of TCE. Most soil gas concentrations of PCE ranged from 0 to 60 ppmv with one well (VEW-22A) as high as 200 ppmv. Air sparging (AS) generally involves the injection of air into the aquifer through either vertical or horizontal wells. AS is coupled with SVE systems when contaminant recovery is necessary. While traditional air sparging (AS) is not a primary component of the DUS process, following the cessation of steam injection, eight (8) of the sixty-three (63) steam injection wells were used to inject air. These wells were previously used for hydrous pyrolysis oxidation (HPO) as part of the DUS process. Air sparging is different from the HPO operations in that the air was injected at a higher rate (20 to 50 scfm) versus HPO (1 to 2 scfm). . At the DUS II site the air injection wells were tested to determine if air sparging affected

  12. Realistic air filter media performance simulation. Part II: Beyond finite-volume computational fluid dynamics procedures

    OpenAIRE

    Tronville, Paolo Maria

    2013-01-01

    One form of numerical simulation of flow and particle capture by air filter media sees gases as continuous fluids, influenced by the macro-properties viscosity, density, and pressure. The alternate approach treats gases as atoms or molecules in random motion, impacting their own kind and solid surfaces on a micro-scale. The appropriate form for analysis of flow through a given filter medium at a given operating condition depends on the gas condition and the Knudsen number (Kn) of the finest f...

  13. Air filtration in the free molecular flow regime: a review of high-efficiency particulate air filters based on carbon nanotubes.

    Science.gov (United States)

    Li, Peng; Wang, Chunya; Zhang, Yingying; Wei, Fei

    2014-11-01

    Air filtration in the free molecular flow (FMF) regime is important and challenging because a higher filtration efficiency and lower pressure drop are obtained when the fiber diameter is smaller than the gas mean free path in the FMF regime. In previous studies, FMF conditions have been obtained by increasing the gas mean free path through reducing the pressure and increasing the temperature. In the case of carbon nanotubes (CNTs) with nanoscale diameters, it is possible to filtrate in the FMF regime under normal conditions. This paper reviews recent progress in theoretical and experimental studies of air filtration in the FMF regime. Typical structure models of high-efficiency particulate (HEPA) air filters based on CNTs are introduced. The pressure drop in air filters operated in the FMF regime is less than that predicted by the conventional air filtration theory. The thinnest HEPA filters fabricated from single-walled CNT films have an extremely low pressure drop. CNT air filters with a gradient nanostructure are shown to give a much better filtration performance in dynamic filtration. CNT air filters with a hierarchical structure and an agglomerated CNT fluidized bed air filter are also introduced. Finally, the challenges and opportunities for the application of CNTs in air filtration are discussed.

  14. Influence of storage on the fungal concentration determination of impinger and filter samples.

    Science.gov (United States)

    Lin, Wen-Hai; Li, Chih-Shan

    2003-01-01

    The effects of storage on concentrations of airborne fungal samples were evaluated in a laboratory test chamber. Spores of Penicillium citrinum and cells of Candida famata var. flareri were aerosolized by a Pitt-3 generator and a Collison nebulizer, respectively. The evaluated sampling methods were AGI-30 impingers, Nuclepore filters, and gelatin filters. The effect of storage time was determined as the ratio, C(t)/C(0), where C(t) and C(0) were the total counts or colony concentrations of the simultaneously collected samples stored for t and 0 hr, respectively. In addition, the effect of storage temperature was investigated by storing AGI-30 and filter samples at 25 and 4 degrees C. The results demonstrated that the culturability of Penicillium spores in the impinger samples decreased as storage time increased. In contrast, the Candida yeast cells could survive and reproduce more cells in the impinger fluid. Moreover, it was observed that refrigeration of the impinger samples could inhibit the growth rate of collected cells. Therefore, it was suggested that the impinger samples should be refrigerated and processed as soon as possible to avoid the loss of spore culturability or the increase of yeast cells. Regarding the filtration methods, the effect of storage time and temperature for Penicillium spores was demonstrated to be insignificant. However, Candida yeast recovery from filters was found to decrease as storage time increased. PMID:12570402

  15. On the structurization of coal dust precipitations and their influence on aerodynamic resistance by granulated mediums in air filters at nuclear power plants

    CERN Document Server

    Neklyudov, I M; Fedorova, L I; Poltinin, P Ya

    2012-01-01

    The processes of structurization of dust precipitations in granulated filtering mediums, formed by the monolithic glass spherical granules with the diameters of 2mm and 3mm, are re-searched. The distinctions between the distributions of filtered coal dust masses in the air filters with cylindrical granules and the air filters with spherical granules, are found. The influences by the filtered dust masses on the air resistance of both the air filters with the cylindrical granules and the air filters with the spherical granules are described. The conclusions on a possibility of the use of various chemical adsorbents with different geometric forms and volumetric dimensions to improve the filtering properties of granulated filtering mediums in air filters at nuclear power plants are formulated.

  16. Sampling density for the quantitative evaluation of air trapping

    Energy Technology Data Exchange (ETDEWEB)

    Goris, Michael L. [Stanford University School of Medicine, Division of Nuclear Medicine, Stanford, CA (United States); Robinson, Terry E. [Stanford University School of Medicine, Center of Excellence in Pulmonary Biology, Pulmonary Division, Department of Pediatrics, Stanford, CA (United States)

    2009-03-15

    Concerns have been expressed recently about the radiation burden on patient populations, especially children, undergoing serial radiological testing. To reduce the dose one can change the CT acquisition settings or decrease the sampling density. In this study we determined the minimum desirable sampling density to ascertain the degree of air trapping in children with cystic fibrosis. Ten children with cystic fibrosis in stable condition underwent a volumetric spiral CT scan. The degree of air trapping was determined by an automated algorithm for all slices in the volume, and then for 1/2, 1/4, to 1/128 of all slices, or a sampling density ranging from 100% to 1% of the total volume. The variation around the true value derived from 100% sampling was determined for all other sampling densities. The precision of the measurement remained stable down to a 10% sampling density, but decreased markedly below 3.4%. For a disease marker with the regional variability of air trapping in cystic fibrosis, regardless of observer variability, a sampling density below 10% and even more so, below 3.4%, apparently decreases the precision of the evaluation. (orig.)

  17. Sampling density for the quantitative evaluation of air trapping

    International Nuclear Information System (INIS)

    Concerns have been expressed recently about the radiation burden on patient populations, especially children, undergoing serial radiological testing. To reduce the dose one can change the CT acquisition settings or decrease the sampling density. In this study we determined the minimum desirable sampling density to ascertain the degree of air trapping in children with cystic fibrosis. Ten children with cystic fibrosis in stable condition underwent a volumetric spiral CT scan. The degree of air trapping was determined by an automated algorithm for all slices in the volume, and then for 1/2, 1/4, to 1/128 of all slices, or a sampling density ranging from 100% to 1% of the total volume. The variation around the true value derived from 100% sampling was determined for all other sampling densities. The precision of the measurement remained stable down to a 10% sampling density, but decreased markedly below 3.4%. For a disease marker with the regional variability of air trapping in cystic fibrosis, regardless of observer variability, a sampling density below 10% and even more so, below 3.4%, apparently decreases the precision of the evaluation. (orig.)

  18. Penggunaan Unit Slow Sand Filter, Ozon Generator dan Rapid Sand Filter Skala Rumah Tangga Untuk Meningkatkan Kualitas Air Sumur Dangkal Menjadi Air Layak Minum (Parameter Zat Organik dan Deterjen

    Directory of Open Access Journals (Sweden)

    Anindya Prawita Sari

    2014-09-01

    Full Text Available Air sumur merupakan air tanah yang sering kali digunakan masyarakat untuk aktivitas sehari-hari. Air sumur dengan kadar organik dan deterjen tinggi tidak layak dikonsumsi masyarakat karena dapat menyebabkan berbagai macam penyakit. Selain itu, adanya zat organik dan deterjen mempengaruhi warna dan bau air sumur sehingga tidak layak konsumsi. Slow sand filter merupakan unit pengolahan yang mampu meremoval zat organik pada air. Slow sand filter dan rapid sand filter tidak menggunakan bahan kimia dalam proses pengolahan sehingga lebih ekonomis dan efektif. Sedangkan ozon, efektif digunakan untuk meremoval zat organik yang ada dalam air dengan mengubah rantai zat organik menjadi lebih sederhana. Tujuan penelitian ini adalah untuk mengetahui keefektifan penggunaan slow sand filter, ozon generator dan rapid sand filter dalam menyisihkan beban deterjen dan zat organik pada air sumur. Hasil penelitian menunjukkan bahwa efisiensi removal pada unit slow sand filter untuk beban organik dan deterjen sebesar 57,6% dan 60,5 %, pada unit ozonasi sebesar 47,4% dan 17,5%, dan pada unit rapid sand filter sebesar 50,0% dan 50,9 %.

  19. A Hybrid Monte Carlo Sampling Filter for Non-Gaussian Data Assimilation

    Directory of Open Access Journals (Sweden)

    Adrian Sandu

    2015-12-01

    Full Text Available Data assimilation combines information from models, measurements, and priors to obtain improved estimates of the state of a dynamical system such as the atmosphere. Ensemble-based data assimilation approaches such as the Ensemble Kalman filter (EnKF have gained wide popularity due to their simple formulation, ease of implementation, and good practical results. Many of these methods are derived under the assumption that the underlying probability distributions are Gaussian. It is well accepted, however, that the Gaussianity assumption is too restrictive when applied to large nonlinear models, nonlinear observation operators, and large levels of uncertainty. When the Gaussianity assumptions are severely violated, the performance of EnKF variations degrades. This paper proposes a new ensemble-based data assimilation method, named the sampling filter, which obtains the analysis by sampling directly from the posterior distribution. The sampling strategy is based on a Hybrid Monte Carlo (HMC approach that can handle non-Gaussian probability distributions. Numerical experiments are carried out using the Lorenz-96 model and observation operators with different levels of non-linearity and differentiability. The proposed filter is also tested with shallow water model on a sphere with linear observation operator. Numerical results show that the sampling filter performs well even in highly nonlinear situations where the traditional filters diverge.

  20. Sampling frequency guidance for ambient air toxics monitoring.

    Science.gov (United States)

    Bortnick, Steven M; Stetzer, Shannon L

    2002-07-01

    The U.S. Environmental Protection Agency (EPA) is in the process of designing a national network to monitor hazardous air pollutants (HAPs), also known as air toxics. The purposes of the expanded monitoring are to (1) characterize ambient concentrations in representative areas; (2) provide data to support and evaluate dispersion and receptor models; and (3) establish trends and evaluate the effectiveness of HAP emission reduction strategies. Existing air toxics data, in the form of an archive compiled by EPA's Office of Air Quality Planning and Standards (OAQPS), are used in this paper to examine the relationship between estimated annual average (AA) HAP concentrations and their associated variability. The goal is to assess the accuracy, or bias and precision, with which the AA can be estimated as a function of ambient concentration levels and sampling frequency. The results suggest that, for several air toxics, a sampling schedule of 1 in 3 days (1:3) or 1:6 days maybe appropriate for meeting some of the general objectives of the national network, with the more intense sampling rate being recommended for areas expected to exhibit relatively high ambient levels. PMID:12139351

  1. Influence of sampling filter type on the mutagenicity of diesel exhaust particulate extracts

    Science.gov (United States)

    Clark, Charles R.; Truex, Timothy J.; Lee, Frank S. C.; Salmeen, Irving T.

    The effects of filter types on the mutagenicity and chemical characteristics of organic extracts of diesel engine particulate exhaust were studied by collecting exhaust particles in a dilution tube simultaneously on three different types of filters: Teflon membrane (Zefluor), Teflon impregnated glass fiber (Pallflex T60A20), and a quartz fiber (Pallflex 2500QAO). The particles were extracted with dichloromethane and subsequently with acetonitrile. The dichloromethane extracts were evaluated in the Salmonella reversion (Ames) assay using strains TA 98, TA 100 and TA 1538 and analyzed by high performance liquid chromatography (HPLC) with fluorescence detection. The filter loadings ranged from 0.3 to 0.7 mg cm -2, typical of loadings in studies of diesel engine particulate exhaust. No major differences in relative concentrations were observed in the polycyclic aromatic hydrocarbon, oxygenated or transition fractions for the three filter types. Furthermore, no differences in the mutagenicity of the samples could be detected.

  2. Gaussian Filter based on Deterministic Sampling for High Quality Nonlinear Estimation

    OpenAIRE

    Huber, Marco F.; Hanebeck, Uwe D.

    2008-01-01

    In this paper, a Gaussian filter for nonlinear Bayesian estimation is introduced that is based on a deterministic sample selection scheme. For an effective sample selection, a parametric density function representation of the sample points is employed, which allows approximating the cumulative distribution function of the prior Gaussian density. The computationally demanding parts of the optimization problem formulated for approximation are carried out off-line for obtaining an efficient filt...

  3. Polycyclic aromatic hydrocarbons in air samples of meat smokehouses

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Olsen, I L; Poulsen, O M

    1992-01-01

    In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors or approx...

  4. Development of a high-efficiency, high-performance air filter medium

    International Nuclear Information System (INIS)

    A unique high-efficiency particulate air (HEPA) filter medium has been developed for applications in high temperature and high pressure environments. This filter medium is a composite made from quartz and stainless-steel fibers that have been sintered together. The composite medium has the same efficiency and pressure drop as standard HEPA glass media, but has four times the tensile strength and can operate continuously at temperatures up to 500/degree/C. In a conventional HEPA, the binder burns out above 250/degree/C and the medium loses its strength; our composite filter medium has no comparable loss of strength even at 500/degree/C. 8 refs., 8 figs., 1 tab

  5. Determination of selected heavy metals in air samples from the northern part of Jordan.

    Science.gov (United States)

    Gharaibeh, Ahmad A; El-Rjoob, Abdul-Wahab O; Harb, Mohammed K

    2010-01-01

    In this work, the atmospheric concentrations of selected heavy metals including lead (Pb), iron (Fe), cadmium (Cd), copper (Cu), nickel (Ni), manganese (Mn), and zinc (Zn) were measured for two different sampling sites (urban and rural) in the northern part of Jordan (Irbid city). Samples were collected according to a certain schedule for 1 year. High volume air samplers and glass fiber filters were used to collect the samples. Collected samples were digested using a mixture of analytical grade nitric acid and analytical grade hydrochloric acid, and analyzed to evaluate the levels of heavy metals by atomic absorption spectrophotometry. Six heavy metals (Pb, Fe, Cu, Ni, Mn, and Zn) were measured in all samples; the concentrations of Cd and Co were not detected in Irbid atmosphere by atomic absorption spectroscopy. The results were used to determine the levels of heavy metal pollutants in air, possible sources, and to compare the levels of selected heavy metals in the two studied sites. Aerosols from the rural site have lower concentrations for all the metals compared to those from the urban site. The daily and monthly variations of the elements were investigated. All heavy metals in urban and rural sites reached maximum concentrations in June, July, and August. This is consistent with the increased activities leading to particulate matter emission during the summer period. The enrichment factors with respect to earth crust and correlation coefficients of heavy metals were investigated to predict the possible sources of heavy metals in air. PMID:19083108

  6. Aging assessment of nuclear air-treatment system HEPA filters and adsorbers

    International Nuclear Information System (INIS)

    A Phase I aging assessment of high-efficiency particulate air (HEPA) filters and activated carbon gas adsorption units (adsorbers) was performed by the Pacific Northwest Laboratory (PNL) as part of the US Nuclear Regulatory Commission's (NRC) Nuclear Plant Aging Research (NPAR) Program. Information concerning design features; failure experience; aging mechanisms, effects, and stressors; and surveillance and monitoring methods for these key air-treatment system components was compiled. Over 1100 failures, or 12 percent of the filter installations, were reported as part of a Department of Energy (DOE) survey. Investigators from other national laboratories have suggested that aging effects could have contributed to over 80 percent of these failures. Tensile strength tests on aged filter media specimens indicated a decrease in strength. Filter aging mechanisms range from those associated with particle loading to reactions that alter properties of sealants and gaskets. Low radioiodine decontamination factors associated with the Three Mile Island (TMI) accident were attributed to the premature aging of the carbon in the adsorbers. Mechanisms that can lead to impaired adsorber performance include oxidation as well as the loss of potentially available active sites as a result of the adsorption of pollutants. Stressors include heat, moisture, radiation, and airborne particles and contaminants

  7. Controls of nitrite oxidation in ammonia-removing biological air filters

    DEFF Research Database (Denmark)

    Juhler, Susanne; Ottosen, Lars Ditlev Mørck; Nielsen, Lars Peter;

    2008-01-01

    analysis. Furthermore, the effect of varying air load and water exchange was investigated. Absence of NOB in many filters was explained by the inhibitory effect of Free Ammonia (FA). When first established, NOB induced a self-perpetuating effect through oxidation of nitrite which allowed increased AOB...... activity resulting in a lowered pH and thus a decreased FA concentration, promoting further growth of NOB. Yet, in some cases a situation with a nitrate-to-nitrite ratio of 1 and moderate pH remained stable even under varying air load and water supply, suggesting that additional mechanisms were involved...

  8. Problems in creation of modern air inlet filters of power gas turbine plants in Russia and methods of their solving

    Science.gov (United States)

    Mikhaylov, V. E.; Khomenok, L. A.; Sherapov, V. V.

    2016-08-01

    The main problems in creation and operation of modern air inlet paths of gas turbine plants installed as part of combined-cycle plants in Russia are presented. It is noted that design features of air inlet filters shall be formed at the stage of the technical assignment not only considering the requirements of gas turbine plant manufacturer but also climatic conditions, local atmospheric air dustiness, and a number of other factors. The recommendations on completing of filtration system for air inlet filter of power gas turbine plants depending on the facility location are given, specific defects in design and experience in operation of imported air inlet paths are analyzed, and influence of cycle air preparation quality for gas turbine plant on value of operating expenses and cost of repair works is noted. Air treatment equipment of various manufacturers, influence of aerodynamic characteristics on operation of air inlet filters, features of filtration system operation, anti-icing system, weather canopies, and other elements of air inlet paths are considered. It is shown that nonuniformity of air flow velocity fields in clean air chamber has a negative effect on capacity and aerodynamic resistance of air inlet filter. Besides, the necessity in installation of a sufficient number of differential pressure transmitters allowing controlling state of each treatment stage not being limited to one measurement of total differential pressure in the filtration system is noted in the article. According to the results of the analysis trends and methods for modernization of available equipment for air inlet path, the importance of creation and implementation of new technologies for manufacturing of filtering elements on sites of Russia within the limits of import substitution are given, and measures on reliability improvement and energy efficiency for air inlet filter are considered.

  9. Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques

    Science.gov (United States)

    Heredia Rivera, Birmania; Gerardo Rodriguez, Martín

    2016-01-01

    Particulate matter accumulated on car engine air-filters (CAFs) was examined in order to investigate the potential use of these devices as efficient samplers for collecting street level air that people are exposed to. The morphology, microstructure, and chemical composition of a variety of particles were studied using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The particulate matter accumulated by the CAFs was studied in two categories; the first was of removed particles by friction, and the second consisted of particles retained on the filters. Larger particles with a diameter of 74–10 µm were observed in the first category. In the second one, the detected particles had a diameter between 16 and 0.7 µm. These particles exhibited different morphologies and composition, indicating mostly a soil origin. The elemental composition revealed the presence of three groups: mineral (clay and asphalt), metallic (mainly Fe), and biological particles (vegetal and animal debris). The palynological analysis showed the presence of pollen grains associated with urban plants. These results suggest that CAFs capture a mixture of atmospheric particles, which can be analyzed in order to monitor urban air. Thus, the continuous availability of large numbers of filters and the retroactivity associated to the car routes suggest that these CAFs are very useful for studying the high traffic zones within a city. PMID:27706087

  10. Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques

    Directory of Open Access Journals (Sweden)

    Birmania Heredia Rivera

    2016-10-01

    Full Text Available Particulate matter accumulated on car engine air-filters (CAFs was examined in order to investigate the potential use of these devices as efficient samplers for collecting street level air that people are exposed to. The morphology, microstructure, and chemical composition of a variety of particles were studied using scanning electron microscopy (SEM and energy-dispersive X-ray (EDX. The particulate matter accumulated by the CAFs was studied in two categories; the first was of removed particles by friction, and the second consisted of particles retained on the filters. Larger particles with a diameter of 74–10 µm were observed in the first category. In the second one, the detected particles had a diameter between 16 and 0.7 µm. These particles exhibited different morphologies and composition, indicating mostly a soil origin. The elemental composition revealed the presence of three groups: mineral (clay and asphalt, metallic (mainly Fe, and biological particles (vegetal and animal debris. The palynological analysis showed the presence of pollen grains associated with urban plants. These results suggest that CAFs capture a mixture of atmospheric particles, which can be analyzed in order to monitor urban air. Thus, the continuous availability of large numbers of filters and the retroactivity associated to the car routes suggest that these CAFs are very useful for studying the high traffic zones within a city.

  11. Detecting discontinuities in time series of upper air data: Demonstration of an adaptive filter technique

    Energy Technology Data Exchange (ETDEWEB)

    Zurbenko, I.; Chen, J.; Rao, S.T. [State Univ. of New York, Albany, NY (United States)] [and others

    1997-11-01

    The issue of global climate change due to increased anthropogenic emissions of greenhouse gases in the atmosphere has gained considerable attention and importance. Climate change studies require the interpretation of weather data collected in numerous locations and/or over the span of several decades. Unfortunately, these data contain biases caused by changes in instruments and data acquisition procedures. It is essential that biases are identified and/or removed before these data can be used confidently in the context of climate change research. The purpose of this paper is to illustrate the use of an adaptive moving average filter and compare it with traditional parametric methods. The advantage of the adaptive filter over traditional parametric methods is that it is less effected by seasonal patterns and trends. The filter has been applied to upper air relative humidity and temperature data. Applied to generated data, the filter has a root mean squared error accuracy of about 600 days when locating changes of 0.1 standard deviations and about 20 days for changes of 0.5 standard deviations. In some circumstances, the accuracy of location estimation can be improved through parametric techniques used in conjunction with the adaptive filter.

  12. Methods for Sampling and Measurement of Compressed Air Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Stroem, L.

    1976-10-15

    In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

  13. In-air micro-pixe analysis of tissue samples

    International Nuclear Information System (INIS)

    Micro-PIXE is capable of providing spatial distributions of elements in the micro-meter scale and its application to biology is useful to elucidate the cellular metabolism. Since, in this method, a sample target is usually irradiated with proton or α-particle beams in vacuum, beam heating results in evaporation of volatile elements an shrinking of the sample. In order to avoid these side effects, we previously developed a technique of in-air micro-PIXE analysis for samples of cultured cells. In addition to these, analysis of exposed tissue samples from living subjects is highly desirable in biological and medical research. Here, we describe a technique of in-air micro-PIXE analysis of such tissue samples. The target samples of exposed tissue slices from a Donryu rat, in which a tumor had been transplanted, were analyzed with proton micro-beams of 2.6 MeV. We report that the shape of cells and the distribution of volatile elements in the tissue sample remain uncharged when using a target preparation based on a freeze-drying method. (author)

  14. Methods for Sampling and Measurement of Compressed Air Contaminants

    International Nuclear Information System (INIS)

    In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

  15. Polyphase Filter Banks for Embedded Sample Rate Changes in Digital Radio Front-Ends

    DEFF Research Database (Denmark)

    Awan, Mehmood-Ur-Rehman; Le Moullec, Yannick; Koch, Peter;

    2011-01-01

    This paper presents efficient processing engines for software-defined radio (SDR) front-ends. These engines, based on a polyphase channelizer, perform arbitrary sample-rate changes, frequency selection, and bandwidth control. This paper presents an M-path polyphase filter bank based on a modified...

  16. The effect of sampling noise in ensemble-based Kalman filters

    Science.gov (United States)

    Sacher, William

    Ensemble-based Kalman filters have drawn a lot of attention in the atmospheric and ocean scientific community because of their potential to be used as a data assimilation tool for numerical prediction in a strongly nonlinear context at an affordable cost. However, many studies have noted practical problems in their implementation. Indeed, being Monte-Carlo methods, the useful parameters are estimated from a sample of limited size of independent realizations of the process. As a consequence, the unavoidable sampling noise impacts the quality of the analysis. An idealized perfect model context is considered in which the analytical expression for the analysis accuracy and reliability as a function of the ensemble size is established, from a second-order moment perspective. It is proved that one can analytically explain the general tendency for ensemble-based Kalman filters to underestimate, on average, the analysis variance and therefore the likeliness for these filters to diverge. Performance of alternative methods, designed to reduce or eliminate sampling error effects, such as the double ensemble Kalman filter or covariance inflation are also analytically explored. For methods using perturbed observations, it is shown that the covariance inflation is the easiest and least expensive method to obtain the most accurate and reliable analysis. These analytical results agreed well with means over a large number of experiments using a perfect, low-resolution, and quasi-geostrophic barotropic model, in a series of observation system simulation experiments of single analysis cycles as well as in a simulated forecast system. In one-analysis cycle experiments with rank histograms, non-perturbed-observation methods show a lack of reliability regardless of the number of members. For small ensemble sizes, sampling error effects are dominant but have a smaller impact than in the perturbed observation method, making non-perturbed-observation method filters much less subject to

  17. Determination of metal content in atmospheric dust samples using different vessel and filter materials

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, G.; Wentrup, G.J.

    1989-02-01

    In this paper materials like glassfibre and quartzglass filters were analysed with respect to their application for the analysis of metal contents in atmospheric dust samples. Furthermore different vessel materials, resistant to fluoric acid, have been tested too. In summary the most important fact for the determination of metal content in atmospheric dust samples - prior condition the chosen analysis method is suitable and sensitive enough - is the quality of the used materials. These materials are to be chosen thoroughly to the conditions required.

  18. Features of adsorbed radioactive chemical elements and their isotopes distribution in iodine air filters AU-1500 at nuclear power plants

    CERN Document Server

    Neklyudov, I M; Dikiy, N P; Ledenyov, O P; Lyashko, Yu V

    2013-01-01

    The main aim of research is to investigate the physical features of spatial distribution of the adsorbed radioactive chemical elements and their isotopes in the granular filtering medium in the iodine air filters of the type of AU1500 in the forced exhaust ventilation systems at the nuclear power plant. The gamma activation analysis method is applied to accurately characterize the distribution of the adsorbed radioactive chemical elements and their isotopes in the granular filtering medium in the AU1500 iodine air filter after its long term operation at the nuclear power plant. The typical spectrum of the detected chemical elements and their isotopes in the AU1500 iodine air filter, which was exposed to the bremsstrahlung gamma quantum irradiation, produced by the accelerating electrons in the tantalum target, are obtained. The spatial distributions of the detected chemical element 127I and some other chemical elements and their isotopes in the layer of absorber, which was made of the cylindrical coal granule...

  19. Design of an online spot air sampling system

    International Nuclear Information System (INIS)

    In all the alpha handling facilities spot air sampling is essential while clearing a lab consequent to week end ventilation shut down or subsequent to completion of work/operations goes inside the facility. The sampling head is designed for 5 micron particles. Following pints are noticed over a period of such operational activities: Health Physicist goes inside a lab with a half face mask whose protection factor is 10, thereby useful for lab air activity up to ten DACs. Many times HP goes inside the lab when activity is more which is highly unsafe. On many occasions simultaneously a number of samples have to be taken by HP from a large number of laboratories inside the facility or for any special job where continuous radiological protection is required. Based on this it is proposed to design a sampling system which will overcome the above limitations. The design of the sampling head has been carried out which is for 5 micron particle size. The pump which is available in the existing facilities can be utilized. An innovative way of counting for large number of samples is fabricated in the RHC wing, RMD which can count ten samples at a time. Removal and counting of the sample may be carried out in a similar sampling carousel which is being used in RHC Unit, Radiometallurgy wing successfully with a little modification. In the proposed system, three samples can be operated in-line such that health physics intervention during the active operation would be minimum and during alarm situations (i.e. on the DAC level) proper protective equipment shall be advised by health physicist or he may suggest any other protective action. This type of online monitors will help in establishing the airborne activity inside the lab where special jobs are being carried out which will provide maximum protection to the lab personnel as well as to the health physicist who supervises the entire operation

  20. A novel method for air drying aloe leaf slices by covering with filter papers as a shrink-proof layer.

    Science.gov (United States)

    Kim, S A; Baek, J H; Lee, S J; Choi, S Y; Hur, W; Lee, S Y

    2009-01-01

    To prevent the shrinkage of aloe vera slices during air drying, a method utilizing a shrink-proof layer was developed. The sample was configured of whole leaf aloe slices, where 1 side or both sides were covered with filter papers as shrink-proof layers. After air drying by varying the air temperature and the slice thickness, the drying characteristics, as well as several quality factors of the dried aloe vera leaf slices, were analyzed. In the simulation of the drying curves, the modified Page model showed the best fitness, representing a diffusion-controlled drying mechanism. Nonetheless, there was a trace of a constant-rate drying period in the samples dried by the method. Shrinkage was greatly reduced, and the rehydration ratios increased by approximately 50%. Scanning electron microscopic analysis revealed that the surface structure of original fibrous form was well sustained. FT-IR characteristics showed that the dried samples could sustain aloe polysaccharide acetylation. Furthermore, the functional properties of the dried slices including water holding capacity, swelling, and fat absorption capability were improved, and polysaccharide retention levels increased by 20% to 30%. Therefore, we concluded that application of shrink-proof layers on aloe slices provides a novel way to overcome the shrinkage problems commonly found in air drying, thereby improving their functional properties with less cost. Practical Application: This research article demonstrates a novel air drying method using shrink-proof layers to prevent the shrinkage of aloe slices. We analyzed extensively the characteristics of shrinkage mechanism and physical properties of aloe flesh gels in this drying system. We concluded that this method can be a beneficial means to retain the functional properties of dried aloe, and a potential alternative to freeze drying, which is still costly. PMID:20492108

  1. Revisiting Atmospheric Lead in NYC - Comparison of Archived Air Filters to Urban Park Sediments and Soils

    Science.gov (United States)

    Chillrud, S. N.; Ross, J. M.; Yan, B.; Bopp, R.

    2015-12-01

    Urban lake sediments have the potential to be used for reconstructing history of aerosols, providing data before the start of urban air quality monitoring. In a previous study, the similarity between radionuclide and excess Pb inventories (57 g/m^2) in Central Park Lake (CPL) sediments and those same parameters in Central Park soils (CPS) was interpreted to indicate that urban lake sediment cores from CPL represent deposition of atmospheric aerosols over the history of the park, which was constructed in the 1860s. Furthermore, metal ratios and metal chronologies indicated that incineration was the major source of Pb to the NYC atmosphere over the 20th century. In this report, we compare the lake chronologies for metals to a set of archived air filters collected by the Department of Energy's Environmental Measurement Lab (EML). These weekly filters of total suspended particulates (TSP) were collected by a high volume sampler located in lower Manhattan for radionuclides as part of the program focused on documenting radioactive fallout from nuclear weapons testing. Metal concentrations measured in subsamples of the EML filters collected between the 1970s to 1990s showed Pb decreasing more slowly than the records of Pb added to gasoline. Metal ratios in the filters were similar to the ratios measured in CPL sediments; the Pb to Sn ratios were roughly 20:1 and the Pb to Zn ratios were in close to 1. The similarity of the ratios provides additional solid support that the CP Lake sediment cores reflect atmospheric inputs. The enrichment of Pb in the large aerosol particle fraction (TSP), relative to fine PM2.5 fraction, demonstrates that the resuspended NYC soils and their historical contaminant burden, are the primary, current source of Pb to NYC air.

  2. The Recent Development of the Test Standards for Ventilation air filters and Cabin Air Filters%通风和座舱空气过滤器试验标准的最新进展

    Institute of Scientific and Technical Information of China (English)

    丰兰

    2011-01-01

    The test standards and methods for two different air filters of ventilation air filters and cabin air filters were introduced,especially the difference of the test standards and methods between the ventilation air filters and cabin air filters.And the international present situation and the problem existed internal were also pointed,finally the development of cabin air filters were analyzed.%主要介绍了通风用空气过滤器和座舱式空气过滤器两个不同类型的空气过滤器的试验方法和标准,重点介绍了各试验方法和标准的区别,阐述分析了目前国际的现状和国内普遍存在的问题,最后介绍了目前座舱式空气过滤器的发展,为进一步研究提供参考。

  3. Calculation software for efficiency and penetration of a fibrous filter medium based on the mathematical models of air filtration

    OpenAIRE

    Kouropoulos, Giorgos

    2014-01-01

    At this article will be created a software written in visual basic for efficiency and penetration calculation in a fibrous filter medium for given values of particles diameter that are retained in the filter. Initially, will become report of mathematical models of air filtration in fibrous filters media and then will develop the code and the graphical interface of application, that are the base for software creation in the visual basic platform.

  4. Aerosol sampler with remote air flow control and online radioactivity measurement above the filter

    International Nuclear Information System (INIS)

    The Czech national Radiation Monitoring Network is equipped with JL-150 aerosol samplers 150 m3/h air flow rate. An upgraded design of this system is proposed. The features of the upgraded aerosol sampler include remote air flow rate control via pump power, maintaining the adjusted flow rate constant, sending status information either on demand or automatically on any change, online gamma spectra acquisition above the aerosol filter and their automatic evaluation, comparison of selected regions of a spectrum with the reference levels and automatic signalling when they are exceeded. The minimum detectable activities of 131I and 137Cs, which may be present in the air in case of NPP accident, are at tenths of Bq/m3 for 1 hour measuring time. (orig.)

  5. Porous filtering media comparison through wet and dry sampling of fixed bed gasification products

    International Nuclear Information System (INIS)

    The syngas produced by fixed bed gasifiers contains high quantities of particulate and tars. This issue, together with its high temperature, avoids its direct exploitation without a proper cleaning and cooling process. In fact, when the syngas produced by gasification is used in an Internal Combustion engine (IC), the higher the content of tars and particulate, the higher the risk to damage the engine is. If these compounds are not properly removed, the engine may fail to run. A way to avoid engine fails is to intensify the maintenance schedule, but these stops will reduce the system profitability. From a clean syngas does not only follow higher performance of the generator, but also less pollutants in the atmosphere. When is not possible to work on the gasification reactions, the filter plays the most important role in the engine safeguard process. This work is aimed at developing and comparing different porous filters for biomass gasifiers power plants. A drum filter was developed and tested filling it with different filtering media available on the market. As a starting point, the filter was implemented in a Power Pallet 10 kW gasifier produced by the California-based company ''ALL Power Labs''. The original filter was replaced with different porous biomasses, such as woodchips and corn cobs. Finally, a synthetic zeolites medium was tested and compared with the biological media previously used. The Tar Sampling Protocol (TSP) and a modified ''dry'' method using the Silica Gel material were applied to evaluate the tars, particulate and water amount in the syngas after the filtration process. Advantages and disadvantages of every filtering media chosen were reported and discussed

  6. Application of wavelet filtering and Barker-coded pulse compression hybrid method to air-coupled ultrasonic testing

    Science.gov (United States)

    Zhou, Zhenggan; Ma, Baoquan; Jiang, Jingtao; Yu, Guang; Liu, Kui; Zhang, Dongmei; Liu, Weiping

    2014-10-01

    Air-coupled ultrasonic testing (ACUT) technique has been viewed as a viable solution in defect detection of advanced composites used in aerospace and aviation industries. However, the giant mismatch of acoustic impedance in air-solid interface makes the transmission efficiency of ultrasound low, and leads to poor signal-to-noise (SNR) ratio of received signal. The utilisation of signal-processing techniques in non-destructive testing is highly appreciated. This paper presents a wavelet filtering and phase-coded pulse compression hybrid method to improve the SNR and output power of received signal. The wavelet transform is utilised to filter insignificant components from noisy ultrasonic signal, and pulse compression process is used to improve the power of correlated signal based on cross-correction algorithm. For the purpose of reasonable parameter selection, different families of wavelets (Daubechies, Symlet and Coiflet) and decomposition level in discrete wavelet transform are analysed, different Barker codes (5-13 bits) are also analysed to acquire higher main-to-side lobe ratio. The performance of the hybrid method was verified in a honeycomb composite sample. Experimental results demonstrated that the proposed method is very efficient in improving the SNR and signal strength. The applicability of the proposed method seems to be a very promising tool to evaluate the integrity of high ultrasound attenuation composite materials using the ACUT.

  7. Polyphase Filter Banks for Embedded Sample Rate Changes in Digital Radio Front-Ends

    Institute of Scientific and Technical Information of China (English)

    Mehmood A wan; Yannick Le Moullec; Peter Koch; Fred Harris

    2011-01-01

    This paper presents efficient processing engines for software-defined radio (SDR) front-ends. These engines, based on a polyphase channelizer, perform arbitrary sample-rate changes, frequency selection, and bandwidth control. This paper presents an M-path polyphase filter bank based on a modified N-path polyphase filter. Such a system allows resampling by arbitrary ratios while performing baseband aliasing from center frequencies at Nyquist zones that are not multiples of the output sample rate. This resampling technique is based on sliding cyclic data load interacting with cyclic-shifted coefficients. A non-maximally-decimated polyphase filterbank (where the number of data loads is not equal to the number of M subfilters) processes M subfilters in a time period that is less than or greater than the M data loads. A polyphase filter bank with five different resampling modes is used as a case study for embedded resamp/ing in SDR front-ends. These modes are (i) maximally decimated, (ii) Under-decimated, (iii) over-decimated, and combined up- and down-sampling with (iv) single stride length, and (v) multiple stride lengths. These modes can be used to obtain any required rational sampling rate change in an SDR front-end based on a polyphase channelizer. They can also be used for translation to and from arbitrary center frequencies that are unrelated to the output sample rates.

  8. Improvement on Diversity Gain with Filter Bandwidth Enlargement in Fractional Sampling OFDM Receiver

    Science.gov (United States)

    Shinkai, Toshiya; Nishimura, Haruki; Sanada, Yukitoshi

    A diversity scheme with Fractional Sampling (FS) in an OFDM receiver has been investigated recently. Through FS, it is possible to separate multipath components and obtain diversity gain in OFDM systems. Enlargement of the bandwidth of the total frequency response between transmit and receive baseband filters allows the FS scheme to achieve path diversity. However, the transmit filter has to be designed according to the spectrum mask of the wireless standards such as IEEE802.11a/g to avoid interference to the other communication systems and the frequency response of the composite channel including the transmit and receive filters has often been set to minimal bandwidth to eliminate adjacent channel signals. In order to achieve the maximum signal-to-noise ratio (SNR), the same filter is commonly used in the transmitter and the receiver. In this paper, the trade-off among the SNR deterioration, adjacent channel interference, and the diversity gain due to the enlargement of the bandwidth of the receive filter is investigated. Numerical results from computer simulations indicate that the BER performance with wider bandwidth in the receiver shows better performance than that with the minimal bandwidth for maximizing the SNR in certain conditions.

  9. Passive air sampling of gaseous elemental mercury: a critical review

    Science.gov (United States)

    McLagan, David S.; Mazur, Maxwell E. E.; Mitchell, Carl P. J.; Wania, Frank

    2016-03-01

    Because gaseous elemental mercury (GEM) is distributed globally through the atmosphere, reliable means of measuring its concentrations in air are important. Passive air samplers (PASs), designed to be cheap, simple to operate, and to work without electricity, could provide an alternative to established active sampling techniques in applications such as (1) long-term monitoring of atmospheric GEM levels in remote regions and in developing countries, (2) atmospheric mercury source identification and characterization through finely resolved spatial mapping, and (3) the recording of personal exposure to GEM. An effective GEM PAS requires a tightly constrained sampling rate, a large and stable uptake capacity, and a sensitive analytical technique. None of the GEM PASs developed to date achieve levels of accuracy and precision sufficient for the reliable determination of background concentrations over extended deployments. This is due to (1) sampling rates that vary due to meteorological factors and manufacturing inconsistencies, and/or (2) an often low, irreproducible and/or unstable uptake capacity of the employed sorbents. While we identify shortcomings of existing GEM PAS, we also reveal potential routes to overcome those difficulties. Activated carbon and nanostructured metal surfaces hold promise as effective sorbents. Sampler designs incorporating diffusive barriers should be able to notably reduce the influence of wind on sampling rates.

  10. Sampling reconstruction of N-dimensional bandlimited images after multilinear filtering in fractional Fourier domain

    Science.gov (United States)

    Wei, Deyun; Li, Yuanmin

    2013-05-01

    This paper addresses the problem of multidimensional signal reconstruction from generalized samples in fractional Fourier domain including the deterministic case and the stochastic case. The generalized sampling expansion is investigated for the case where the fractional bandlimited input depends on N real variable, i.e., f(t)=f(t1,⋯,tN) and is used as a common input to a parallel bank of m independent N dimensional linear fractional Fourier filters Hα,k(u), k=1,⋯,m. For the deterministic input, the input is assumed to have its N dimensional fractional Fourier transform bandlimited to the frequency rang |ui|≤Ωi, for i=1,⋯,N. If m, the number of fractional Fourier filters, is written as a product of positive integers in the form m=m1m2⋯mN, and if the fractional bandlimited input f(t) is processed by fractional Fourier filter Hα,k(u)resulting m outputs gk(t), then f(t) can be reconstructed in terms of the samples gk(nT), each output being sampled at the identical rates of Ω1 csc α/m1π, Ω2 csc α/m2π,⋯, ΩN csc α/mNπ samples/second in t1,⋯,tN respectively. This contrasts with the rates of Ω1 csc α/π, Ω2 csc α/π,⋯, ΩN csc α/π in t1,⋯,tN needed for reconstruction of the unfiltered input f(t). Input sampling expansions in terms of samples of the output filters are given for both deterministic and stochastic inputs, the generalized sampling expansion for random input having the same form as for the deterministic case but interpreted in the mean-square sense. Our formulation and results are general and include derivative sampling and periodic nonuniform sampling in the fractional Fourier domain for multidimensional signals as special case. Finally, the potensional application of the multidimensional generalized sampling is presented to show the advantage of the theory. Especially, the application of multidimensional generalized sampling in the context of the image scaling about image super-resolution is

  11. Computationally efficient video restoration for Nyquist sampled imaging sensors combining an affine-motion-based temporal Kalman filter and adaptive Wiener filter.

    Science.gov (United States)

    Rucci, Michael; Hardie, Russell C; Barnard, Kenneth J

    2014-05-01

    In this paper, we present a computationally efficient video restoration algorithm to address both blur and noise for a Nyquist sampled imaging system. The proposed method utilizes a temporal Kalman filter followed by a correlation-model based spatial adaptive Wiener filter (AWF). The Kalman filter employs an affine background motion model and novel process-noise variance estimate. We also propose and demonstrate a new multidelay temporal Kalman filter designed to more robustly treat local motion. The AWF is a spatial operation that performs deconvolution and adapts to the spatially varying residual noise left in the Kalman filter stage. In image areas where the temporal Kalman filter is able to provide significant noise reduction, the AWF can be aggressive in its deconvolution. In other areas, where less noise reduction is achieved with the Kalman filter, the AWF balances the deconvolution with spatial noise reduction. In this way, the Kalman filter and AWF work together effectively, but without the computational burden of full joint spatiotemporal processing. We also propose a novel hybrid system that combines a temporal Kalman filter and BM3D processing. To illustrate the efficacy of the proposed methods, we test the algorithms on both simulated imagery and video collected with a visible camera.

  12. The performance and subjective responses of call-center operators with new and used supply air filters at two outdoor air supply rates

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Wyon, David; Fanger, Povl Ole

    2004-01-01

    A 2X2 replicated field intervention experiment was conducted in a call-center providing a telephone directory service: outdoor air supply rate was adjusted to be 8% of the total airflow of 430 l/s (3.5/h)and the supply air filters were either new or had been in place for 6 months. One of these...

  13. 静电净化器应用于空调系统中的探讨%Discussion on Using Electrostatic Air Filter in Air-conditioning System

    Institute of Scientific and Technical Information of China (English)

    丛明滋; 刘泽华; 李井会; 孙祚民

    2011-01-01

    提出使用静电净化器来改善室内空气品质问题。简单介绍静电净化器的装置结构和作用机理。分析静电净化器的技术特点。对比传统纤维过滤器,分析指出静电净化器具有阻力小、作用范围广、运行费用低的优点,应用于洁净空调系统中具有良好的技术优势和经济优势。同时对静电净化器存在的问题进行了分析,建议在静电净化器前加设粗效过滤器、在静电过滤器后加设活性炭纤维层来提高净化效率和降低臭氧浓度。%It is presented to improve indoor air quality by using the electrostatic air filter. The article brief introduces the structure and mechanism of electrostatic air filter, and analyses technical features of electrostatic air filter. Compared with conditional fiber filter, the analysis results indicate that: the electrostatic air filter has the advantages of small resistance, wide work range, low operation cost. And it is with good technical and economic advantages that the electrostatic filters apply in clean air-conditioning system. In addition, the article analyses the existing problems of the electrostatic filter and puts forward some suggestions, such as setting coarse filter and activated carbon fiber layer to improve the purification efficiency and reduce the ozone concentration.

  14. Ice nucleation active particles in continental air samples over Mainz, Germany

    Science.gov (United States)

    Pummer, Bernhard G.; Pöschl, Ulrich; Fröhlich-Nowoisky, Janine

    2016-04-01

    Aerosol particles are of central importance for atmospheric chemistry and physics, climate and public health. Some of these particles possess ice nucleation activity (INA), which is highly relevant for cloud formation and precipitation. In 2010, air filter samples were collected with a high-volume filter sampler separating fine and coarse particles (aerodynamic cut-off diameter 3 μm) in Mainz, Germany. In this study, the INA of the atmospheric particles deposited on these filters was determined. Therefore,they were extracted with ultrapure water, which was then measured in a droplet freezing assay, as described in Fröhlich-Nowoisky et al. (2015). The determined concentration of ice nucleators (INs) was between 0.3 and 2per m³ at 266 K, and between5 and 75 per m³ at 260 K. The INs were further characterized by different treatments, like heating (308 K, 371 K), filtration (0.1 μm, 300 kDa), and digestion with papain (10 mg/ml). We further investigated, which atmospheric conditions (e.g. weather) and distinguished events (e.g. dust storms, volcanic eruptions, and pollen peaks) influenced the number and nature of these INs. Fröhlich-Nowoisky, J., Hill, T. C. J., Pummer, B. G., Yordanova, P., Franc, G. D., and Pöschl, U.: Ice nucleation activity in the widespread soil fungus Mortierella alpina, Biogeosci., 12, 1057-1071, doi:10.5194/bg-12-1057-2015, 2015.

  15. Field Study of Filter Sampling Artifacts for Inorganic and Organic Aerosol Species

    Science.gov (United States)

    Maenhaut, W.; Wang, W.; Chi, X.

    2009-12-01

    It is well-known that the collection of carbonaceous aerosols on quartz fibre filters is prone to both positive and negative artifacts (e.g., Turpin et al., 2000). In studies on these artifacts, one normally concentrates on organic carbon (OC) as a whole or occasionally on water-soluble OC (WSOC). It is rare that studies are carried on individual organic species. Examples of the latter type of study are those by Limbeck et al. (2001; 2005), who used a low-volume tandem filter set-up at a rural background site in South Africa and at the urban site Vienna in Austria, and measured dicarboxylic acids (DCAs) on the front and back filters. We conducted a similar study as those of Limbeck et al. (2001; 2005). For our study we collected high-volume PM2.5 samples during summer field campaigns at three European forested sites, i.e., in Hungary, Belgium, and Finland. The front and back filters of our samples were analysed for OC with a thermal-optical transmission technique (Birch & Cary, 1996), for WSOC as described by Viana et al. (2006), and for water-soluble inorganic cationic and anionic species and organic anionic species by suppressed ion chromatography with conductometric detection. The organic species measured included methanesulphonic acid (MSA) and the four major DCAs, i.e., oxalic, malonic, succinic, and glutaric. The median back/front percentage ratios for ammonium and sulphate were low, below 5% and 1%, respectively, but for nitrate they were around 25-30%. That undenuded filter samplings for nitrate are prone to artifacts is well-documented (e.g., Schaap et al., 2004). For OC the median back/front percentage ratios were around 15% and for WSOC around 20%. For MSA and the four DCAs, they increased in the following order: oxalic (1.5%), succinic (3%), MSA (4%), malonic (2-9%), glutaric (7-26%). Our back/front ratios for three of the four DCAs are lower to much lower than these found by Limbeck et al. (2001; 2005); for malonic, however, we found higher back

  16. Dengue-3 outbreak in Paraguay: investigations using capillary blood samples on filter paper.

    Science.gov (United States)

    Matheus, Severine; Meynard, Jean-Baptiste; Lavergne, Anne; Girod, Romain; Moua, David; Labeau, Bhety; Dussart, Philippe; Lacoste, Vincent; Deparis, Xavier

    2008-11-01

    During a dengue-3 outbreak in Paraguay at the beginning of 2007, capillary blood samples absorbed onto filter papers were collected from 44 suspected cases. These samples were subjected to three molecular and serologic tests, and 31 of the 44 samples gave a positive result by at least one of the techniques used. Molecular analyses detected the dengue-3 serotype in 22 patients and additionally the dengue-2 serotype in two patients. Therefore two different serotypes were co-circulating during this outbreak. Overall, this study validates the use of dried-blood samples for field screening investigations. Indeed, all types of laboratory studies of dengue were possible with samples consisting of a few drops of dried blood from finger pricks.

  17. Shot noise reduced terahertz detection via spectrally post-filtered electro-optic sampling

    CERN Document Server

    Porer, Michael; Huber, Rupert

    2016-01-01

    In ultrabroadband terahertz electro-optic sampling, spectral filtering of the gate pulse can strongly reduce the quantum noise while the signal level is only weakly affected. The concept is tested for phase-matched electro-optic detection of field transients centered at 45 THz with 12-fs near-infrared gate pulses in AgGaS2. Our new approach increases the experimental signal-to-noise ratio by a factor of 3 compared to standard electro-optic sampling. Under certain conditions an improvement factor larger than 5 is predicted by our theoretical analysis.

  18. Phase I aging assessment of nuclear air-treatment system HEPA filters and adsorbers

    International Nuclear Information System (INIS)

    A Phase I aging assessment of high-efficiency particulate 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 Nuclear Plant Aging Research Program. Information was compiled concerning design features; failure experience; aging mechanisms, effects, and stressors; and monitoring methods. Over 1100 failures, or 12 percent of the filter installations, were reported as part of a U.S. Department of Energy survey. Investigators from other laboratories have suggested that aging could have contributed to over 80 percent of these failures. Several instances of impaired performance as the result of the premature aging of carbon were reported. Filter aging mechanisms range from those associated with particle loading to reactions that alter properties of gaskets. Mechanisms that can lead to impaired adsorber performance include the loss of potentially available active sites as a result of the adsorption of moisture or pollutants. Stressors include heat, moisture, radiation and airborne particles and contaminants

  19. Adaptive Kalman Filter Based on Adjustable Sampling Interval in Burst Detection for Water Distribution System

    Directory of Open Access Journals (Sweden)

    Doo Yong Choi

    2016-04-01

    Full Text Available Rapid detection of bursts and leaks in water distribution systems (WDSs can reduce the social and economic costs incurred through direct loss of water into the ground, additional energy demand for water supply, and service interruptions. Many real-time burst detection models have been developed in accordance with the use of supervisory control and data acquisition (SCADA systems and the establishment of district meter areas (DMAs. Nonetheless, no consideration has been given to how frequently a flow meter measures and transmits data for predicting breaks and leaks in pipes. This paper analyzes the effect of sampling interval when an adaptive Kalman filter is used for detecting bursts in a WDS. A new sampling algorithm is presented that adjusts the sampling interval depending on the normalized residuals of flow after filtering. The proposed algorithm is applied to a virtual sinusoidal flow curve and real DMA flow data obtained from Jeongeup city in South Korea. The simulation results prove that the self-adjusting algorithm for determining the sampling interval is efficient and maintains reasonable accuracy in burst detection. The proposed sampling method has a significant potential for water utilities to build and operate real-time DMA monitoring systems combined with smart customer metering systems.

  20. Effect of an Air Cleaner with Electrostatic Filter on the Removal of Airborne House Dust Mite Allergens

    OpenAIRE

    Agrawal, Santosh Rani; Kim, Hak-Joon; Lee, Yong Won; Sohn, Jung-Ho; Lee, Jae Hyun; Kim, Yong-Jin; Lee, Sung-Hwa; Hong, Chein-Soo; Park, Jung-Won

    2010-01-01

    Purpose The effects of air cleaners on the removal of airborne indoor allergens, especially house dust mites (HDM), are still controversial. The objective of this study is to evaluate the effect of an air cleaner with an electrostatic filter on the removal of airborne mite allergens. Materials and Methods A dried HDM culture medium that contained mite body particles and excretions was dispersed in a chamber equipped with an electrostatic air cleaner. The number of airborne particles was recor...

  1. Air quality benefits of universal particle filter and NOx controls on diesel trucks

    Science.gov (United States)

    Tao, L.; Mcdonald, B. C.; Harley, R.

    2015-12-01

    Heavy-duty diesel trucks are a major source of black carbon/particulate matter and nitrogen oxide emissions on urban and regional scales. These emissions are relevant to both air quality and climate change. Since 2010 in the US, new engines are required to be equipped with emission control systems that greatly reduce both PM and NOx emissions, by ~98% relative to 1988 levels. To reduce emissions from the legacy fleet of older trucks that still remain on the road, regulations have been adopted in Califonia to accelerate the replacement of older trucks and thereby reduce associated emissions of PM and NOx. Use of diesel particle filters will be widespread by 2016, and universal use of catalytic converters for NOx control is required by 2023. We assess the air quality consequences of this clean-up effort in Southern California, using the Community Multiscale Air Quality model (CMAQ), and comparing three scenarios: historical (2005), present day (2016), and future year (2023). Emissions from the motor vehicle sector are mapped at high spatial resolution based on traffic count and fuel sales data. NOx emissions from diesel engines in 2023 are expected to decrease by ~80% compared to 2005, while the fraction of NOx emitted as NO2 is expected to increase from 5 to 18%. Air quality model simulations will be analyzed to quantify changes in NO2, black carbon, particulate matter, and ozone, both basin-wide and near hot spots such as ports and major highways.

  2. Modelling of the filter-adsorber type air cleaner by using neural network

    Directory of Open Access Journals (Sweden)

    Raos Miomir

    2009-01-01

    Full Text Available It is well known that most air purifying methods imply the passing of air flow, as a pollutant carrier, through a control unit which retains impurities. Properties of the air control unit and the purifying process itself therefore differ depending on the nature of present impurities, as well as on flow-thermal properties of air as the carrier of those impurities. For the assumed conditions, in terms of production of a pollution source and presence of different polluting substances in the form of dust, aerosols, gas, vapor in the exhaust gas, etc., an integrated gas purifier has been designed and tested, comprising a module for purification of mechanical impurities and a module for purification of gaseous impurities. The purifier is compact and has a universal application while simultaneously retaining several different pollutants. These requirements were met through application of the filtration and adsorption methods. On the formed experimental line with an adequate system of acquisition, filter-adsorber type gas cleaners in the function of flow-thermal parameters of gas mixture were tested simultaneously. Experimental data were used for training the radial basis function neural network, which was then used to model properties of the process and gas cleaner.

  3. Define and Quantify the Physics of Air Flow, Pressure Drop and Aerosol Collection in Nuclear Grade HEPA Filters

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-23

    Objective: Develop a set of peer-review and verified analytical methods to adjust HEPA filter performance to different flow rates, temperatures and altitudes. Experimental testing will measure HEPA filter flow rate, pressure drop and efficiency to verify the analytical approach. Nuclear facilities utilize HEPA (High Efficiency Particulate Air) filters to purify air flow for workspace ventilation. However, the ASME AG-1 technical standard (Code on Nuclear Air and Gas Treatment) does not adequately describe air flow measurement units for HEPA filter systems. Specifically, the AG-1 standard does not differentiate between volumetric air flow in ACFM (actual cubic feet per minute)compared to mass flow measured in SCFM (standard cubic feet per minute). More importantly, the AG-1 standard has an overall deficiency for using HEPA filter devices at different air flow rates, temperatures, and altitudes. Technical Approach: The collection efficiency and pressure drops of 18 different HEPA filters will be measured over a range of flow rates, temperatures and altitudes. The experimental results will be compared to analytical scoping calculations. Three manufacturers have allocated six HEPA filters each for this effort. The 18 filters will be tested at two different flow rates, two different temperatures and two different altitudes. The 36 total tests will be conducted at two different facilities: the ATI Test facilities (Baltimore MD) and the Los Alamos National Laboratory (Los Alamos NM). The Radiation Protection RP-SVS group at Los Alamos has an aerosol wind tunnel that was originally designed to evaluate small air samplers. In 2010, modifications were started to convert the wind tunnel for HEPA filter testing. (Extensive changes were necessary for the required aerosol generators, HEPA test fixtures, temperature control devices and measurement capabilities.) To this date, none of these modification activities have been funded through a specific DOE or NNSA program. This is

  4. Experimental data required for the design and analysis of emergency filtered air discharge sytems

    International Nuclear Information System (INIS)

    The radiological consequences of an accident in a CANDU nuclear generating station are mitigated by special safety systems which include an Emergency Filtered Air Discharge (EFAD) system. EFAD systems are designed to provide a controlled leakage path following an accident. They remove radioiodine and particulates from the air discharge required, to inhibit uncontrolled emissions by maintaining containment sub-atmospheric in the long term. The design and analysis of an EFAD system requires an accurate data base comprised of the numerous parameters involved in the simulation of fission product behaviour within containment. This paper emphasizes the data requirements of EFAD system design with regard to those parameters which preliminary sensitivity analyses have shown to most effect environmental releases. These include the source term radioisotopes; their chemical behaviour and distribution within containment; the repressurization time during the vacuum hold-up period; and parameters effecting the long term releases through the EFAD system. The net radioiodine trapping efficiency of charcoal filters in the long term is dependent on the adsorption efficiency and desorption of the deep charcoal bed. These are a function of many parameters such as impregnate, aging, humidity, temperature, radiation, recirculation, etc. Although the effect of these parameters on charcoal filters has been individually investigated, generally at ideal or extreme values, there is little applicable data to determine their combined effect under expected post accident operating conditions. As a consequence, designers tend to overdesign by using unduly conservative parameters. A summary comparison is presented to illustrate the information gap between the experimental data from the literature and the data required for optimal design and analysis of the EFAD systems

  5. Extended-life nuclear air cleaning filters via dynamic exclusion prefilters

    Energy Technology Data Exchange (ETDEWEB)

    Wright, S.R.; Crouch, H.S.; Bond, J.H. [Micro Composite Materials Corp., Durham, NC (United States)

    1997-08-01

    The primary objective of this investigation was to ascertain if a dynamic, self-cleaning particulate exclusion precleaner, designed for relatively large dust removal (2 to 100+ {mu}m diameter particles) from helicopter turbine inlets, could be extended to submicron filtration. The improved device could be used as a prefilter for HEPA filtration systems, significantly increasing service life. In nuclear air cleaning, its use would reduce the amount of nuclear particulate matter that would otherwise be entrapped in the HEPA filter cartridge/panel, causing fouling and increased back pressure, as well as requiring subsequent disposal of the contaminated media at considerable expense. A unique (patent-pending) mechanical separation device has recently been developed to extract particulate matter from fluid process streams based on a proprietary concept called Boundary Layer Momentum Transfer (BLMT). The device creates multiple boundary layers that actively exclude particles from entering the perimeter of the device, while allowing air to traverse the boundaries relatively unimpeded. A modified two-dimensional (2-D) computerized flow simulation model was used to assist in the prototype design. Empirical results are presented from particle breakthrough and AP experiments obtained from a reduced-scale prototype filter. Particles larger than 0.23 {mu}m were actively excluded by the prototype, but at a higher pressure drop than anticipated. Experimental data collected indicates that the filter housing and the inlet flow configuration may contribute significantly to improvements in device particle separation capabilities. Furthermore, preliminary experiments have shown that other downstream pressure drop considerations (besides those just across the spinning filtration disks) must be included to accurately portray the AP across the device. Further detailed quantitative investigations on a larger scale (1,000 CFM) prototype are warranted. 3 refs., 5 figs., 2 tabs.

  6. Determination of mercury in airborne particulate matter collected on glass fiber filters using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sampling

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Rennan G.O., E-mail: rgoa01@terra.com.br [Laboratorio de Quimica Analitica Ambiental, Departamento de Quimica, Universidade Federal de Sergipe, Campus Sao Cristovao, 49.100-000, Sao Cristovao, SE (Brazil); Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, SC (Brazil); Vignola, Fabiola; Castilho, Ivan N.B. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, SC (Brazil); Borges, Daniel L.G.; Welz, Bernhard [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, SC (Brazil); Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador, BA (Brazil); Vale, Maria Goreti R. [Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador, BA (Brazil); Instituto de Quimica, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, RS (Brazil); Smichowski, Patricia [Comision Nacional de Energia Atomica (CNEA) and Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina); Ferreira, Sergio L.C. [Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador, BA (Brazil); Instituto de Quimica, Universidade Federal da Bahia, 40170-290, Salvador, BA (Brazil); Becker-Ross, Helmut [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V., Department Berlin, 12489 Berlin (Germany)

    2011-05-15

    A study has been undertaken to assess the capability of high-resolution continuum source graphite furnace atomic absorption spectrometry for the determination of mercury in airborne particulate matter (APM) collected on glass fiber filters using direct solid sampling. The main Hg absorption line at 253.652 nm was used for all determinations. The certified reference material NIST SRM 1648 (Urban Particulate Matter) was used to check the accuracy of the method, and good agreement was obtained between published and determined values. The characteristic mass was 22 pg Hg. The limit of detection (3{sigma}), based on ten atomizations of an unexposed filter, was 40 ng g{sup -1}, corresponding to 0.12 ng m{sup -3} in the air for a typical air volume of 1440 m{sup 3} collected within 24 h. The limit of quantification was 150 ng g{sup -1}, equivalent to 0.41 ng m{sup -3} in the air. The repeatability of measurements was better than 17% RSD (n = 5). Mercury concentrations found in filter samples loaded with APM collected in Buenos Aires, Argentina, were between < 40 ng g{sup -1} and 381 {+-} 24 ng g{sup -1}. These values correspond to a mercury concentration in the air between < 0.12 ng m{sup -3} and 1.47 {+-} 0.09 ng m{sup -3}. The proposed procedure was found to be simple, fast and reliable, and suitable as a screening procedure for the determination of mercury in APM samples.

  7. A Modified Integer Coded Genetic Algorithm Design of Time-Variant Staggered Sampling MTI Filter

    Institute of Scientific and Technical Information of China (English)

    TAOHaihong; LIAOGuisheng; WANGLing

    2005-01-01

    The stagger time-variant sampling MTI filter design is an effective method to reject clutter and alleviate the blind speed problem. Selecting the suitable stagger-code to make the nadir shallow can avoid the loss of weak target in it. Also multi-model clutters can be suppressed by MTI filter, and blind-velocity can appear out of three times velocity of sound. So the low speed weak target can be detected out of strong multl-model clutters. The paper presents a modified Integer coded genetic algorithm (ICGA) including some strategies to select the optimal stagger-code. By comparing with other traditional algorithm, GA is a global stochastic searching method and can converge quickly. The simulation and performance analysis demonstrate the feasibility and validity of this algorithm.

  8. Improvement of self-cleaning type air filter%自洁式空气过滤器的改进

    Institute of Scientific and Technical Information of China (English)

    王鹏

    2012-01-01

    The self-cleaning type air filter is fitted before air inlet pipe of air compressor completed for air separation plant. The domestic-made carriage has low service life, and in case of highly wet air the filter paper is liable to stick, which lowers the filtering efficiency, results in frequent repair of air compressor repair, and seriously impairs prolonged stable run of air separation plant. The service life of carriage of self-cleaning type air filter is extended and the filtering efficiency is improved through use of the non-woven filtering cotton blended with compound fiber, the carriage made of compound fiber, and the imported filter paper, adjustment of its programmable controller, and change of its back-blowing pressure and air supply. Here, the work principle of self- cleaning type air filter is briefed, the problems during its operation process are analyzed, and the implementation process and economic benefits of the improvement measures are described.%空分设备配套空压机进气管前设置自洁式空气过滤器,由于国内生产的滤筒使用寿命短,遇含湿量大的空气时滤纸易黏连,进而影响过滤效率,导致空压机检修频繁,严重影响了空分设备长周期稳定运行。通过增加复合纤维无纺滤棉,选用复合纤维滤筒和进口滤纸,调整自洁式空气过滤器的编程控制仪,以及改变反吹压力和反吹气源,达到延长自洁式空气过滤器的滤筒寿命和提高过滤效率的目的。简述自洁式空气过滤器的工作原理,分析其使用过程中存在的问题,阐述改进措施的实施过程及取得的经济效益。

  9. The performance and subjective responses of call-center operators with new and used supply air filters at two outdoor air supply rates

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Wyon, David; Fanger, Povl Ole

    2004-01-01

    of these independent variables was changed each week for 8 weeks. The interventions did not affect room temperature, relative humidity or noise level. The 26 operators were blind to conditions and each week returned questionnaires recording their environmental perceptions and Sick Building Syndrome (SBS) symptoms......% with a new filter in place but increased talk-time by 8% with a used filter in place. The interventions also had significant effects on some SBS symptoms and environmental perceptions. The present results indicate that increasing outdoor air supply rate and replacing filters can have positive effects...

  10. Environmental DNA sampling protocol - filtering water to capture DNA from aquatic organisms

    Science.gov (United States)

    Laramie, Matthew B.; Pilliod, David S.; Goldberg, Caren S.; Strickler, Katherine M.

    2015-09-29

    Environmental DNA (eDNA) analysis is an effective method of determining the presence of aquatic organisms such as fish, amphibians, and other taxa. This publication is meant to guide researchers and managers in the collection, concentration, and preservation of eDNA samples from lentic and lotic systems. A sampling workflow diagram and three sampling protocols are included as well as a list of suggested supplies. Protocols include filter and pump assembly using: (1) a hand-driven vacuum pump, ideal for sample collection in remote sampling locations where no electricity is available and when equipment weight is a primary concern; (2) a peristaltic pump powered by a rechargeable battery-operated driver/drill, suitable for remote sampling locations when weight consideration is less of a concern; (3) a 120-volt alternating current (AC) powered peristaltic pump suitable for any location where 120-volt AC power is accessible, or for roadside sampling locations. Images and detailed descriptions are provided for each step in the sampling and preservation process.

  11. Environmental DNA sampling protocol - filtering water to capture DNA from aquatic organisms

    Science.gov (United States)

    Laramie, Matthew B.; Pilliod, David S.; Goldberg, Caren S.; Strickler, Katherine M.

    2015-01-01

    Environmental DNA (eDNA) analysis is an effective method of determining the presence of aquatic organisms such as fish, amphibians, and other taxa. This publication is meant to guide researchers and managers in the collection, concentration, and preservation of eDNA samples from lentic and lotic systems. A sampling workflow diagram and three sampling protocols are included as well as a list of suggested supplies. Protocols include filter and pump assembly using: (1) a hand-driven vacuum pump, ideal for sample collection in remote sampling locations where no electricity is available and when equipment weight is a primary concern; (2) a peristaltic pump powered by a rechargeable battery-operated driver/drill, suitable for remote sampling locations when weight consideration is less of a concern; (3) a 120-volt alternating current (AC) powered peristaltic pump suitable for any location where 120-volt AC power is accessible, or for roadside sampling locations. Images and detailed descriptions are provided for each step in the sampling and preservation process.

  12. Energy-filtered transmission electron microscopy of biological samples on highly transparent carbon nanomembranes

    CERN Document Server

    Rhinow, Daniel; Weber, Nils-Eike; Beyer, André; Gölzhäuser, Armin; Kühlbrandt, Werner; Hampp, Norbert; Turchanin, Andrey; 10.1016/j.ultramic.2011.01.028

    2011-01-01

    Ultrathin carbon nanomembranes (CNM) comprising crosslinked biphenyl precursors have been tested as support films for energy-filtered transmission electron microscopy (EFTEM) of biological specimens. Due to their high transparency CNM are ideal substrates for electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) of stained and unstained biological samples. Virtually background-free elemental maps of tobacco mosaic virus (TMV) and ferritin have been obtained from samples supported by ~ 1 nm thin CNM. Furthermore, we have tested conductive carbon nanomembranes (cCNM) comprising nanocrystalline graphene, obtained by thermal treatment of CNM, as supports for cryoEM of ice-embedded biological samples. We imaged ice-embedded TMV on cCNM and compared the results with images of ice-embedded TMV on conventional carbon film (CC), thus analyzing the gain in contrast for TMV on cCNM in a quantitative manner. In addition we have developed a method for the preparation of vitrified specimens, sus...

  13. Efficacy of serum samples stored on filter paper for the detection of antibody to Leptospira spp. by microagglutination test (MAT).

    Science.gov (United States)

    Blanco, R M; Romero, E C

    2012-12-14

    The aim of this study was to investigate the microagglutination test (MAT) results in serum samples dried on filter paper and stored at different temperatures during 1day, 7days, 30days and 1year to determine the stability of sera antibody against leptospires. Serum samples collected onto filter paper for the detection of leptospires antibody was compared with MAT in a study of 300 serum samples from patients with suspected leptospirosis. Among 300 fresh serum samples analyzed by MAT 156 (52%) were positive and 144 (48%) negative. All the negative fresh serum samples were negative when dried on filter paper (specificity 100%). The sensitivity of MAT performed on dried serum samples was 100%. Storage on filter paper at room temperature and at 4°C for 1 and 7days did not affect the MAT titers. For up to 7days, 98.72% of dried serum samples had titers identical to those of the corresponding serum samples, and 1.18% of dried serum samples showed 1 dilution of difference. After a storage period of one month a prozone phenomenon was observed. After a storage period of one year all serum samples were negative. Serum samples collected onto filter paper are a convenient source of antibodies for serological diagnosis and epidemiological surveys. PMID:22960422

  14. Measurements of Fission Products from the Fukushima Daiichi Incident in San Francisco Bay Area Air Filters, Automobile Filters, Rainwater, and Food

    CERN Document Server

    Smith, A R; Norman, E B; Hurley, D L; Lo, B T; Chan, Y D; Guillaumon, P V; Harvey, B G

    2013-01-01

    A variety of environmental media were analyzed for fallout radionuclides resulting from the Fukushima nuclear accident by the Low Background Facility (LBF) at the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, CA. Monitoring activities in air and rainwater began soon after the onset of the March 11, 2011 tsunami and are reported here through the end of 2012. Observed fallout isotopes include $^{131}$I, $^{132}$I,$^{132}$Te,$^{134}$Cs, $^{136}$Cs, and $^{137}$Cs. Isotopes were measured on environmental air filters, automobile filters, and in rainwater. An additional analysis of rainwater in search of $^{90}$Sr is also presented. Last, a series of food measurements conducted in September of 2013 are included due to extended media concerns of $^{134, 137}$Cs in fish. Similar measurements of fallout from the Chernobyl disaster at LBNL, previously unpublished publicly, are also presented here as a comparison with the Fukushima incident. All measurements presented also include natural radionuclides found...

  15. Geostationary Coastal and Air Pollution Events (GeoCAPE) Filter Radiometer (FR)

    Science.gov (United States)

    Kotecki, Carl; Chu, Martha; Wilson, Mark; Clark, Mike; Nanan, Bobby; Matson, Liz; McBirney, Dick; Smith, Jay; Earle, Paul; Choi, Mike; Stoneking, Eric; Luu, Kequan; Swinski, J. P.; Secunda, Mark; Brall, Aron; Verma, Sanjay; Hartman, Kathy R.

    2014-01-01

    The GeoCAPE Filter Radiometer (FR) Study is a different instrument type than all of the previous IDL GeoCape studies. The customer primary goals are to keep mass, volume and cost to a minimum while meeting the science objectives and maximizing flight opportunities by fitting on the largest number of GEO accommodations possible. Minimize total mission costs by riding on a commercial GEO satellite. For this instrument type, the coverage rate, km 2 min, was significantly increased while reducing the nadir ground sample size to 250m. This was accomplished by analyzing a large 2d area for each integration period. The field of view will be imaged on a 4k x 4k detector array of 15 micrometer pixels. Each ground pixel is spread over 2 x 2 detector pixels so the instantaneous field of view (IFOV) is 2048 X 2048 ground pixels. The baseline is, for each field of view 50 sequential snapshot images are taken, each with a different filter, before indexing the scan mirror to the next IFOV. A delta would be to add additional filters.

  16. 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)

    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)

  17. Influence by small dispersive coal dust particles of different fractional consistence on characteristics of iodine air filter at nuclear power plant

    CERN Document Server

    Neklyudov, I M; Fedorova, L I; Poltinin, P Ya

    2013-01-01

    The main purpose of research is to determine the influence by the small dispersive coal dust particles of the different fractional consistence on the technical characteristics of the vertical iodine air filter at nuclear power plant. The research on the transport properties of the small dispersive coal dust particles in the granular filtering medium of absorber in the vertical iodine air filter is completed in the case, when the modeled aerodynamic conditions are similar to the real aerodynamic conditions. It is shown that the appearance of the different fractional consistence of small dispersive coal dust particles with the decreasing dimensions down to the micro and nano sizes at the action of the air dust aerosol stream normally results in a significant change of distribution of the small dispersive coal dust particles masses in the granular filtering medium of an absorber in the vertical iodine air filter, changing the vertical iodine air filter aerodynamic characteristics. The precise characterization of...

  18. THE EFFECT OF THE REYNOLDS NUMBER OF AIR FLOW TO THE PARTICLE COLLECTION EFFICIENCY OF A FIBROUS FILTER MEDIUM WITH CYLINDRICAL SECTION

    Directory of Open Access Journals (Sweden)

    George P. Kouropoulos

    2014-01-01

    Full Text Available At this study an attempt for the theoretical approach of the Re ynolds number effect of air flow to the particle collection efficiency of a fibrous fil ter with cylindrical section will be made. Initially, a report of the air filtration models to fibrous filter media will be presented along with an explanation of both the parameters and the physical quantities which govern the air filtration process. Furthermore, the resul ting equation from the mathematical model will be applied to a real filter medium and the characteristic curves of filter efficiency will be drawn. The change of a filter medi um efficiency with regard to the Reynolds number of air flow that passes through the filt er, derived from the curves, will be studied. The general conclusion that we have is that as the Reynolds number of filtered air increases, the collection efficiency of the filter decreases.

  19. Comparison of filters for concentrating microbial indicators and pathogens in lake-water samples

    Science.gov (United States)

    Francy, Donna S.; Stelzer, Erin A.; Brady, Amie M.G.; Huitger, Carrie; Bushon, Rebecca N.; Ip, Hon S.; Ware, Michael W.; Villegas, Eric N.; Gallardo, Vincent; Lindquist, H.D. Alan

    2013-01-01

    Bacterial indicators are used to indicate increased health risk from pathogens and to make beach closure and advisory decisions; however, beaches are seldom monitored for the pathogens themselves. Studies of sources and types of pathogens at beaches are needed to improve estimates of swimming-associated health risks. It would be advantageous and cost-effective, especially for studies conducted on a regional scale, to use a method that can simultaneously filter and concentrate all classes of pathogens from the large volumes of water needed to detect pathogens. In seven recovery experiments, stock cultures of viruses and protozoa were seeded into 10-liter lake water samples, and concentrations of naturally occurring bacterial indicators were used to determine recoveries. For the five filtration methods tested, the highest median recoveries were as follows: glass wool for adenovirus (4.7%); NanoCeram for enterovirus (14.5%) and MS2 coliphage (84%); continuous-flow centrifugation (CFC) plus Virocap (CFC+ViroCap) for Escherichia coli (68.3%) and Cryptosporidium (54%); automatic ultrafiltration (UF) for norovirus GII (2.4%); and dead-end UF for Enterococcus faecalis (80.5%), avian influenza virus (0.02%), and Giardia (57%). In evaluating filter performance in terms of both recovery and variability, the automatic UF resulted in the highest recovery while maintaining low variability for all nine microorganisms. The automatic UF was used to demonstrate that filtration can be scaled up to field deployment and the collection of 200-liter lake water samples.

  20. Screening for neonatal hypothyroidism by thyroxine and thyrotrophin radioimmunoassays using dried blood samples on filter paper

    International Nuclear Information System (INIS)

    A routine and automated methodology for thyroxine (T4) and thyrotrophin (TSH) radioimmunoassay (RIA) using dried blood samples on filter paper is described. T4-RIA was performed on one single dot (5 mm diameter equivalent to 4 μl of serum) while two dots were necessary for TSH-RIA. Reference filter papers were introduced in each assay for quality control. In a preliminary study on 4,155 neonates, samples generally obtained between the 5th-7th day gave a mean 'dot-T4' of 97.95 +- 36.04 nmol/l and a mean 'dot-TSH' of 10.19 mU/l +- 8.25, corresponding to 2.47 mU/l of serum. Within an 18-month period (November 1976 - April 1978), a total of 16,522 neonates have been screened allowing detection of three cases of congenital hypothyroidism (incidence 1:5507), two cases of congenitally low TBG and thirty-three cases of transient hypothyroidism. (author)

  1. The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

    Directory of Open Access Journals (Sweden)

    Gorji-Bandpy Mofid

    2012-04-01

    Full Text Available This paper presents a computational fluid dynamics (CFD calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

  2. The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

    Science.gov (United States)

    Hoseeinzadeh, Sepideh; Gorji-Bandpy, Mofid

    2012-04-01

    This paper presents a computational fluid dynamics (CFD) calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

  3. Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room.

    Science.gov (United States)

    Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke

    2016-01-01

    Size- and time-dependent aerodynamic behaviors of indoor particles, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different filters. In-situ real-time measurements were taken using an optical particle counter. The filtration characteristics of filter media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret filter (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3-3.5 μm particle size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 10⁴ m³/m². The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-filter (PR) or the active carbon granule filter (CF) was relatively poor. While PAC with the pre-filter and the high efficiency filter (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret filters augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized particles could be greater than for PACs without PR. Without regard to the lifetime, the electret filters performed better with respect to resource saving and purification improvement. A most penetrating particle size range (MPPS: 0.4-0.65 μm) exists in both HE and electret filters; the MPPS tends to become larger after HE and electret filters are combined with PR. These results serve to provide a better understanding of the indoor particle removal performance of PACs when combined with different kinds of filters in school

  4. Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room

    Directory of Open Access Journals (Sweden)

    Huan Ma

    2016-01-01

    Full Text Available Size- and time-dependent aerodynamic behaviors of indoor particles, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different filters. In-situ real-time measurements were taken using an optical particle counter. The filtration characteristics of filter media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret filter (EE medium shows better initial removal efficiency than the high efficiency (HE medium in the 0.3–3.5 μm particle size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 104 m3/m2. The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC with the pre-filter (PR or the active carbon granule filter (CF was relatively poor. While PAC with the pre-filter and the high efficiency filter (PR&HE showed maximum single-pass efficiency for PM1.0 (88.6%, PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret filters augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized particles could be greater than for PACs without PR. Without regard to the lifetime, the electret filters performed better with respect to resource saving and purification improvement. A most penetrating particle size range (MPPS: 0.4–0.65 μm exists in both HE and electret filters; the MPPS tends to become larger after HE and electret filters are combined with PR. These results serve to provide a better understanding of the indoor particle removal performance of PACs when combined with different kinds of filters in

  5. The effects of outdoor air supply rate and supply air filter condition in classrooms on the performance of schoolwork by children (RP-1257)

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Wyon, David Peter

    2007-01-01

    Two independent field intervention experiments were carried out in mechanically ventilated classrooms receiving 100% outdoor air. Outdoor air supply rate and filter condition were manipulated to modify indoor air quality, and the performance of schoolwork was measured The conditions were...... scales to indicate their environmental perceptions and the intensity of any symptoms. The children indicated that the air was fresher but otherwise perceived little difference when the outdoor air supply rate increased from 3.0 to 8.5 L/s (6.4-18 cfm) per person, while the speed at which they performed...... two numerical and two language-based tasks improved significantly. A significant effect of ventilation rate was observed in 70% of all the statistical tests for an effect on work rate, but there were no significant effects on errors. The effects were probably due to improved air quality...

  6. Radiochemical analysis of aerosol filters and precipitation samples by the German Weather Service

    International Nuclear Information System (INIS)

    The German Weather Service routinely analyses air and precipitation samples for the isotopes U-234, U-235, U-238, Am-241, Pu-238, Pu-239/240, Sr-89 and Sr-90. In the presented method, the separation of alpha emitters and strontium isotopes from the same sample is done by a multi-stage extraction chromatography procedure. Alpha-emitting nuclides are electrodeposited and measured by alpha spectrometry, Sr-89 and Sr-90 will be simultaneously determined using a three-window LSC-method. The analysis procedure is used in routine operation, as well, with minor modifications in the intensive operation.

  7. Report on the quality control study NAT-7 for the determination of trace and minor elements in dust artificially loaded on air filters

    International Nuclear Information System (INIS)

    A quality control study was organized on two air filters artificially loaded with urban dust. One dust material was collected from the air intake ducts of the Vienna General Hospital, the second material was collected from the main ventilation shaft of a road tunnel in Prague. 49 laboratories from 40 countries participated in the study, providing 53 sets of results. The following analytical methods were used: neutron activation analysis (NAA), inductive coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), particle induced X-ray emission spectrometry (PDCE), atomic absorption spectrometry (AAS), and X-ray fluorescence spectrometry (XRF). The results were evaluated following the standard LEA procedures for (1) an interlaboratory comparison exercise and (2) a proficiency test using established target values. For the air filter sample V, 754 laboratory mean values for 38 elements were reported. More than 4 mean values were obtained for 26 measurands and these were statistically evaluated. Only 10 % 71 values) of the results were detected as outliers by the statistical data evaluation. The results and statistical parameters are listed in the appendices I and II. The results were also evaluated as a proficiency test using established target values. Precision and accuracy criteria were applied to 15 elements. 534 laboratory mean values were reported for those elements, 114 values (20%) did not pass the set proficiency test criteria. The individual laboratory results are listed in appendix IV. For the air filter sample P, 694 laboratory mean values for 38 elements were reported. More than 4 mean values were obtained for 26 measurands and these were statistically evaluated. Only 9% (60 values) of the results were detected as outliers by the statistical data evaluation. The results and statistical parameters are listed in the appendices I and II. The results were also evaluated as a proficiency test using target values

  8. Semi-volatile organic compounds in heating, ventilation, and air-conditioning filter dust in retail stores.

    Science.gov (United States)

    Xu, Y; Liang, Y; Urquidi, J R; Siegel, J A

    2015-02-01

    Retail stores contain a wide range of products that can emit a variety of indoor pollutants. Among these chemicals, phthalate esters and polybrominated diphenyl ethers (PBDEs) are two important categories of semi-volatile organic compounds (SVOCs). Filters in heating, ventilation, and air-conditioning (HVAC) system collect particles from large volumes of air and thus potentially provide spatially and temporally integrated SVOC concentrations. This study measured six phthalate and 14 PBDE compounds in HVAC filter dust in 14 retail stores in Texas and Pennsylvania, United States. Phthalates and PBDEs were widely found in the HVAC filter dust in retail environment, indicating that they are ubiquitous indoor pollutants. The potential co-occurrence of phthalates and PBDEs was not strong, suggesting that their indoor sources are diverse. The levels of phthalates and PBDEs measured in HVAC filter dust are comparable to concentrations found in previous investigations of settled dust in residential buildings. Significant correlations between indoor air and filter dust concentrations were found for diethyl phthalate, di-n-butyl phthalate, and benzyl butyl phthalate. Reasonable agreement between measurements and an equilibrium model to describe SVOC partitioning between dust and gas-phase is achieved.

  9. Low-cost monitoring of campylobacter in poultry houses by air sampling and quantitative PCR

    DEFF Research Database (Denmark)

    Søndergaard, Mette Sofie Rousing; Josefsen, Mathilde Hasseldam; Löfström, Charlotta;

    2014-01-01

    The present study describes the evaluation of a method for the quantification of Campylobacter by air sampling in poultry houses. Sampling was carried out in conventional chicken houses in Poland, in addition to a preliminary sampling in Denmark. Each measurement consisted of three air samples, t...

  10. Identification of sources of heavy metals in the Dutch atmosphere using air filter and lichen analysis

    International Nuclear Information System (INIS)

    Aerosol samples collected in an industrialized region were analyzed by instrumental neutron activation analysis. Correlation with wind direction and factor analysis were applied to the concentration data to obtain information on the nature and position of the sources. Epiphytic lichens were sampled over the country and analyzed for heavy metals (As, Cd, Sc, Zn, Sb). The data were interpreted by geographically plotting element concentrations and enrichment factors, and by factor analysis. Some pitfalls are discussed which are associated with the use of aerosol and lichen data in studies of heavy metal air pollution. 14 references, 8 figures, 3 tables

  11. Towards "Intelligent Compression" in Streams: A Biased Reservoir Sampling based Bloom Filter Approach

    CERN Document Server

    Dutta, Sourav; Narang, Ankur

    2011-01-01

    With the explosion of information stored world-wide,data intensive computing has become a central area of research.Efficient management and processing of this massively exponential amount of data from diverse sources,such as telecommunication call data records,online transaction records,etc.,has become a necessity.Removing redundancy from such huge(multi-billion records) datasets resulting in resource and compute efficiency for downstream processing constitutes an important area of study. "Intelligent compression" or deduplication in streaming scenarios,for precise identification and elimination of duplicates from the unbounded datastream is a greater challenge given the realtime nature of data arrival.Stable Bloom Filters(SBF) address this problem to a certain extent.However,SBF suffers from a high false negative rate(FNR) and slow convergence rate,thereby rendering it inefficient for applications with low FNR tolerance.In this paper, we present a novel Reservoir Sampling based Bloom Filter,(RSBF) data struc...

  12. HEPAFIL - a program for the calculation of the fluid dynamics of high efficiency particulate air filter units

    International Nuclear Information System (INIS)

    With HEPAFIL, LAF II provides a FORTRAN program for the calculation of various parameters associated with the fluid dynamics of high efficiency particulate air filter units. Most of the currently available commercial deep pleat designs have been taken into consideration, e.g., high strength nuclear grade units employing separators with inclined corrugations, units for clean room applications, as well as low and medium efficiency EU 6 and EU 8 types having very low pressure drops. The flow resistance curves obtained from HEPAFIL could be verified in extensive experimental test. A user-friendly PC version with the integrated program library HEPAGAS can serve as a useful tool to the researcher in filter development as well as to the filter manufacturer for cost reduction analyses. Knowledge of the distributions of airstream, pressures and velocities within the flow channels of the filter pack allows more precise investigations of failure mechanisms and filtration characteristics for a wide range of flow conditions. The newest scientific application involves fundamental investigations into the cleanability of HEPA filter units. HEPAFIL offers filter manufacturers the opportunity to improve and optimize filter performance with respect to pressure drop, burst strength, and material costs, with a minimum of prototype fabrication and testing. (orig.)

  13. Interconversion of chromium species during air sampling: effects of O3, NO2, SO2, particle matrices, temperature, and humidity.

    Science.gov (United States)

    Huang, Lihui; Fan, Zhihua Tina; Yu, Chang Ho; Hopke, Philip K; Lioy, Paul J; Buckley, Brian T; Lin, Lin; Ma, Yingjun

    2013-05-01

    The interconversion between Cr(VI), a pulmonary carcinogen, and Cr(III), an essential human nutrient, poses challenges to the measurement of Cr(VI) in airborne particles. Chamber and field tests were conducted to identify the factors affecting Cr(VI)-Cr(III) interconversion in the basic filter medium under typical sampling conditions. In the chamber tests, isotopically enriched (53)Cr(VI) and (50)Cr(III) were spiked on diesel particulate matter (DPM) and secondary organic aerosol (SOA) that were precollected on a basic MCE filter. The filter samples were then exposed to clean air or the air containing SO2 (50 and 160 ppb), 100 ppb O3, or 150 ppb NO2 for 24 h at 16.7 LPM flow rate at designated temperature (20 and 31 °C) and RH (40% and 70%) conditions. Exposure to 160 ppb SO2 had the greatest effect on (53)Cr(VI) reduction, with (53)Cr(VI) recovery of 31.7 ± 15.8% (DPM) and 42.0 ± 7.9% (SOA). DPM and SOA matrix induced (53)Cr(VI) reduction when exposed to clean air while reactive oxygen species in SOA could promote (50)Cr(III) oxidation. Deliquescence when RH increased from 40% to 70% led to conversion of Cr(III) in SOA, whereas oxidized organics in DPM and SOA enhanced hygroscopicity and thus facilitated Cr(VI) reduction. Field tests showed seasonal variation of Cr(VI)-Cr(III) interconversion during sampling. Correction of the interconversion using USEPA method 6800 is recommended to improve accuracy of ambient Cr(VI) measurements. PMID:23550818

  14. Improved sample filtering method for measuring end-to-end path capacity

    Institute of Scientific and Technical Information of China (English)

    LI Wen-wei; TANG Jun-long; ZHANG Da-fang; XIE Gao-gang

    2007-01-01

    By analyzing the effect of cross traffic (CT) enforced on packet delay, an improved path capacity measurement method,pcapminp algorithm, was proposed. With this method, path capacity was measured by filtering probe samples based on measured minimum packet-pair delay. The measurability of minimum packet-pair delay was also analyzed by simulation. The results show that,when comparing with pathrate, ifthe CT load is light, both pcapminp and pathrate have similar accuracy; but in the case of heavy CT load, pcapminp is more accurate than Pathrate. When CT load reaches 90%, pcapminp algorithm has only 5% measurement error,which is 10% lower than that of pathrate algorithm. At any CT load levels, the probe cost of pcapminp algorithm is two magnitudes smaller than that of pathrate, and the measurement duration is one magnitude shorter than that of pathrate algorithm.

  15. Pemanfaatan Limbah Kulit Kakao Dan Tanah Lempung Sebagai Material Filter Dalam Pengolahan Air Sumur Menjadi Air Bersih

    OpenAIRE

    Sani, Abd

    2016-01-01

    The research has been conducted about utilization of cocoa rind waste and clay as filter material in the processing of deep well into clean water. Research conducted in two step. The first step was manufacture of filter and the second step was application of filter for deep well processing. The cocoa rind waste used as activated carbon mixed with clay in variation of composition activated carbon from cocoa rind : clay 85%:15%, 80%:20%, 75%:25%, 70%:30% and 65%:35%. Futhermore, the filter is b...

  16. Physical features of accumulation and distribution processes of small disperse coal dust precipitations and absorbed radioactive chemical elements in iodine air filter at nuclear power plant

    CERN Document Server

    Ledenyov, Oleg P; Poltinin, P Ya; Fedorova, L I

    2012-01-01

    The physical features of absorption process of radioactive chemical elements and their isotopes in the iodine air filters of the type of AU-1500 at the nuclear power plants are researched. It is shown that the non-homogenous spatial distribution of absorbed radioactive chemical elements and their isotopes in the iodine air filter, probed by the gamma-activation analysis method, is well correlated with the spatial distribution of small disperse coal dust precipitations in the iodine air filter. This circumstance points out to an important role by the small disperse coal dust fractions of absorber in the absorption process of radioactive chemical elements and their isotopes in the iodine air filter. The physical origins of characteristic interaction between the radioactive chemical elements and the accumulated small disperse coal dust precipitations in an iodine air filter are considered. The analysis of influence by the researched physical processes on the technical characteristics and functionality of iodine ...

  17. Physical features of small disperse coal dust fraction transportation and structurization processes in iodine air filters of absorption type in ventilation systems at nuclear power plants

    CERN Document Server

    Ledenyov, Oleg P; Poltinin, P Ya; Fedorova, L I

    2012-01-01

    The research on the physical features of transportation and structurization processes by the air-dust aerosol in the granular filtering medium with the cylindrical coal adsorbent granules in an air filter of the adsorption type in the heating ventilation and cooling (HVAC) system at the nuclear power plant is completed. The physical origins of the coal dust masses distribution along the absorber with the granular filtering medium with the cylindrical coal granules during the air-dust aerosol intake process in the near the surface layer of absorber are researched. The quantitative technical characteristics of air filtering elements, which have to be considered during the optimization of air filters designs for the application in the ventilation systems at the nuclear power plants, are obtained.

  18. Air-core microcavities and metal-dielectric filters - building blocks for optofluidic microsystems

    Science.gov (United States)

    Allen, Trevor Warren

    This thesis describes a study on two optical devices intended to be building blocks for the creation of integrated optical/microfluidic lab-on-a-chip systems. First, arrays of curved-mirror dome-shaped microcavities were fabricated by buckling self-assembly of a-Si/SiO2 multilayers. This novel technique employs controlled, stress-induced film delamination to form highly symmetric cavities with minimal roughness defects or geometrical imperfections. Measured cavity heights were in good agreement with predictions from elastic buckling theory. Also, the measured finesse (> 103) and quality factor (> 104 in the 1550-nm range) were close to reflectance-limited predictions, indicating low defects and roughness. Hermite- and Laguerre-Gaussian modes were observable, indicating a high degree of cylindrical symmetry. In the second part of the research, transmittance in periodic metal-dielectric multilayer structures was studied. Metal-dielectric stacks have many potential applications in optofluidic microsystems, including as transmission filters, superlenses, and substrates for surface plasmon sensors. In this work, we showed that potential transmittance theory provides a good method for describing the tunneling of photons through metal-dielectric stacks, for both Fabry-Perot and surface plasmon resonances. This approach explains the well-known fact that for a given thickness of metal, subdividing the metal into several thin films can increase the maximum transmittance. Conditions for admittance matching of dielectric-metal-dielectric unit cells to an external air medium were explored for Fabry-Perot based tunneling, revealing that thicker metal films require higher-index dielectrics for optimal admittance matching. It was also shown for the first time that potential transmittance theory can be used to predict the maximum possible transmittance in surface-plasmon-mediated tunneling. In a subsequent study, potential transmittance was used to derive an expression for

  19. XANES Speciation of P in Environmental Samples : An Assessment of Filter Media for on-Site Wastewater Treatment

    OpenAIRE

    Eveborn, David; Gustafsson, Jon Petter; Hesterberg, Dean; Hillier, Stephen

    2009-01-01

    X-ray absorption near edge structure (XANES) spectroscopyis a useful technique for characterization of chemical speciesof phosphorus in complex environmental samples. To developand evaluate bed filters as sustainable on-site wastewater treatment solutions, our objective in this study was to determine the chemical forms of accumulated phosphorus in a selectionof promising filter materials: Filtralite P, Filtra P, Polonite, Absol, blast furnace slag, and wollastonite. Full-scale operational was...

  20. Recovery of Cryptosporidium oocysts from small and large volume water samples using a compressed foam filter system.

    Science.gov (United States)

    Sartory, D P; Parton, A; Parton, A C; Roberts, J; Bergmann, K

    1998-12-01

    A novel filter system comprising open cell reticulated foam rings compressed between retaining plates and fitted into a filtration housing was evaluated for the recovery of oocysts of Cryptosporidium from water. Mean recoveries of 90.2% from seeded small and large volume (100-2000 l) tap water samples, and 88.8% from 10-20 l river water samples, were achieved. Following a simple potassium citrate flotation concentrate clean-up procedure, mean recoveries were 56.7% for the tap water samples and 60.9% for river water samples. This represents a marked improvement in capture and recovery of Cryptosporidium oocysts from water compared with conventional polypropylene wound cartridge filters and membrane filters.

  1. Recovery of Cryptosporidium oocysts from small and large volume water samples using a compressed foam filter system.

    Science.gov (United States)

    Sartory, D P; Parton, A; Parton, A C; Roberts, J; Bergmann, K

    1998-12-01

    A novel filter system comprising open cell reticulated foam rings compressed between retaining plates and fitted into a filtration housing was evaluated for the recovery of oocysts of Cryptosporidium from water. Mean recoveries of 90.2% from seeded small and large volume (100-2000 l) tap water samples, and 88.8% from 10-20 l river water samples, were achieved. Following a simple potassium citrate flotation concentrate clean-up procedure, mean recoveries were 56.7% for the tap water samples and 60.9% for river water samples. This represents a marked improvement in capture and recovery of Cryptosporidium oocysts from water compared with conventional polypropylene wound cartridge filters and membrane filters. PMID:9871348

  2. Radioactive Air Emissions Notice of Construction for 105-KW filter vessel sparging vent

    International Nuclear Information System (INIS)

    This document serves as a notice of construction (NOC), pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct, pursuant to 40 Code of Federal Regulations (CFR) 61.07, for the Integrated Water Treatment System (IWTS) Filter Vessel Sparging Vent at 105-KW Basin. Additionally, the following description, and references are provided as the notices of startup, pursuant to 40 CFR 61.09(a)(1) and (2) in accordance with Title 40 Code of Federal Regulations, Part 61, National Emission Standards for Hazardous Air Pollutants. The 105-K West Reactor and its associated spent nuclear fuel (SNF) storage basin were constructed in the early 1950s and are located on the Hanford Site in the 100-K Area about 1,400 feet from the Columbia River. The 105-KW Basin contains 964 Metric Tons of SNF stored under water in approximately 3,800 closed canisters. This SNF has been stored for varying periods of time ranging from 8 to 17 years. The 105-KW Basin is constructed of concrete with an epoxy coating and contains approximately 1.3 million gallons of water with an asphaltic membrane beneath the pool. The IWTS, which has been described in the Radioactive Air Emissions NOC for Fuel Removal for 105-KW Basin (DOE/RL-97-28 and page changes per US Department of Energy, Richland Operations Office letter 97-EAP-814) will be used to remove radionuclides from the basin water during fuel removal operations. The purpose of the modification described herein is to provide operational flexibility for the IWTS at the 105-KW basin. The proposed modification is scheduled to begin in calendar year 1998

  3. Radioactivity in the furnace air-cleaning filter from a house with an unusually high level of airborne radon

    International Nuclear Information System (INIS)

    The amounts of the three short-lived daughters of radon on the furnace air-cleaning filter from a house with a high level of radon were estimated to be 8.2, 33, and 38 kBq (0.22, 0.89, and 1.03 μCi) for 218Po, 214Pb, and 214Bi, respectively, at the time of removal from the furnace. These data were used to calculate the airborne concentrations of the three, and the results indicated that about 70% of the daughters were lost to surfaces in the house and by impaction in the air ducts. The filter's content of 210Pb was found to be 4.4 kBg (0.12 μCi); from this the average concentration of radon-producing filterable daughters during the time the furnace blower operated, was estimated to be 860 Bq m-3. This indicated that there was no significant loss to surfaces or in air ducts. Possible reasons for the difference are given. The filter was also found to contain 1 kBq (27 nCi) of 212Bi from the thorium series

  4. Microbial air-sampling equipment, part 1: meeting United States pharmacopeia chapter 797 standards.

    Science.gov (United States)

    Kastango, Eric S

    2008-01-01

    The most recent changes to Chapter 797 of the United States Pharmcopeia-National Formulary initiated an intense controversy about the frequency of cleanroom air sampling that is required to prevent the contamination of sterile preparations. For compounders who must purchase an air sampler to use in the cleanroom, choices abound. Included in this article are a review of United States Pharmacopeia-National Formulary requirements that pertain to air sampling, a discussion of how recent revision to Chapter 797 affect air sampling and patient safety, and, for easy reference, a table that features specifications for various models of microbial air samplers.

  5. The effect of simulated air conditions on N95 filtering facepiece respirators performance.

    Science.gov (United States)

    Ramirez, Joel A; O'Shaughnessy, Patrick T

    2016-07-01

    The objective of this study was to determine the effect of several simulated air environmental conditions on the particle penetration and the breathing resistance of two N95 filtering facepiece respirator (FFR) models. The particle penetration and breathing resistance of the respirators were evaluated in a test system developed to mimic inhalation and exhalation breathing while relative humidity and temperature were modified. Breathing resistance was measured over 120 min using a calibrated pressure transducer under four different temperature and relative humidity conditions without aerosol loading. Particle penetration was evaluated before and after the breathing resistance test at room conditions using a sodium chloride aerosol measured with a scanning mobility particle sizer. Results demonstrated that increasing relative humidity and lowering external temperature caused significant increases in breathing resistance (p < 0.001). However, these same conditions did not influence the penetration or most penetrating particle size of the tested FFRs. The increase in breathing resistance varied by FFR model suggesting that some FFR media are less influenced by high relative humidity. PMID:26861653

  6. Sampling and analysis plan for ORNL filter press cake waste from the Liquid and Gaseous Waste Operations Department

    International Nuclear Information System (INIS)

    This document defines the sampling and analytical procedures needed for the initial characterization of the filter press cake waste from the Process Waste Treatment Plant (PWTP) at the Oak Ridge National Laboratory (ORNL). It is anticipated that revisions to this document will occur as operating experience and sample results suggest appropriate changes be made. Application of this document will be controlled through the ORNL Waste Management and Remedial Action Division. The sampling strategy is designed to ensure that the samples collected present an accurate representation of the waste process stream. Using process knowledge and preliminary radiological activity screens, the filter press cake waste is known to contain radionuclides. Chemical characterization under the premise of this sampling and analysis plan will provide information regarding possible treatments and ultimately, disposal of filter press cake waste at an offsite location. The sampling strategy and analyses requested are based on the K-25 waste acceptance criteria and the Nevada Test Site Defense Waste Acceptance Criteria, Certification, and Transfer Requirements [2, NVO-325, Rev. 1]. The sampling strategy will demonstrate that for the filter press cake waste there is (1) an absence of RCRA and PCBs wastes, (2) an absence of transuranic (TRU) wastes, and (3) a quantifiable amount of radionuclide activity

  7. Clinical evaluation of the air removal characteristics of an oxygenator with integrated arterial filter in a minimized extracorporeal circuit.

    Science.gov (United States)

    Stehouwer, Marco C; Boers, Chris; de Vroege, Roel; C Kelder, Johannes; Yilmaz, Alaaddin; Bruins, Peter

    2011-04-01

    The use of minimized extracorporeal circuits (MECC) in cardiac surgery is an important measure to increase the biocompatibility of cardiopulmonary bypass during coronary artery bypass grafting (CABG). These circuits eliminate volume storage reservoirs and bubble traps to minimize the circuit. However, the reduction in volume may increase the risk of gaseous microemboli (GME). The MECC system as used by our group consists of a venous bubble trap, centrifugal pump, and an oxygenator. To further reduce the risk of introducing GME, an oxygenator with an integrated arterial filter was developed based on the concept of minimal volume and foreign surface. We studied the air removal characteristics of this oxygenator with and without integrated arterial filter. The quantity and volume of GME were measured with precision at both the inlet and outlet of the devices. Our results showed that integration of an arterial filter into this oxygenator increased GME reducing capacity from 69.2% to 92%. Moreover, we were able to obtain data on the impact of an arterial filter on the exact size-distribution of GME entering the arterial line. The present study demonstrates that an MECC system and oxygenator with integrated arterial filter significantly reduces the volume and size of GME. The use of an integrated arterial filter in an MECC system may protect the patient from the deleterious effects of CPB and may further improve patient safety.

  8. In-syringe magnetic stirring-assisted dispersive liquid-liquid microextraction and silylation prior gas chromatography-mass spectrometry for ultraviolet filters determination in environmental water samples.

    Science.gov (United States)

    Clavijo, Sabrina; Avivar, Jessica; Suárez, Ruth; Cerdà, Víctor

    2016-04-22

    A novel online approach involving in-syringe magnetic stirring assisted dispersive liquid-liquid microextraction and derivatization coupled to gas chromatography-mass spectrometry has been developed for the determination of seven UV filters extensively used in cosmetic products in environmental water samples. The effect of parameters such as the type and volume of extraction solvent, dispersive solvent and derivatization agent, pH, ionic strength and stirring time, was studied using multivariate experimental design. Extraction, derivatization and preconcentration were simultaneously performed using acetone as dispersive solvent, N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) as derivatization agent and trichloroethylene as extraction solvent. After stirring during 160s, the sedimented phase was transferred to a rotary micro-volume injection valve (3 μL) and introduced by an air stream into the injector of the GC through a stainless-steel tube used as interface. The detection limits were in the range of 0.023-0.16 μg L(-1) and good linearity was observed up to 500 μg L(-1) of the studied UV filters, with R(2) ranging between 0.9829 and 0.9963. The inter-day precision expressed as relative standard deviation (n=5) varied between 5.5 and 16.8%. Finally, the developed method was satisfactorily applied to assess the occurrence of the studied UV filters in seawater and pool water samples. Some of the studied UV filters were found in these samples and an add-recovery test was also successfully performed with recoveries between 82 and 111%.

  9. 32 CFR 806.27 - Samples of Air Force FOIA processing documents.

    Science.gov (United States)

    2010-07-01

    ... review will require policy determinations from different Air Force elements; records describe law... 32 National Defense 6 2010-07-01 2010-07-01 false Samples of Air Force FOIA processing documents. 806.27 Section 806.27 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR...

  10. Rapid analytical technique to identify alpha emitting isotopes in water, air-filters, urine, and solid matrices using a Frisch Grid detector.

    Science.gov (United States)

    Scarpitta, Salvatore C; Miltenberger, Robert P; Gaschott, Robert; Carte, Nina

    2003-04-01

    A 5-inch-diameter Frisch Grid gas-proportional ionization chamber was utilized at Brookhaven National Laboratory (BNL) to rapidly characterize and quantify alpha-emitting actinides in unprocessed water, soil, air-filter, urine, and solid matrices. Instrument calibrations for the various matrices were performed by spiking representative samples with National Institute of Standards and Technology traceable isotopes of 230Th, 232U, 236Pu, and 243Am. Detection efficiencies were typically 15-20% for solid matrices (soil, concrete, filters, dry urine) and 45% for mass-less water samples. Instrument background over a 512-channel alpha-energy range of 3-8 MeV is very low at 0.01 cps. At optimum efficiency, minimum detectable levels of 0.56 mBq Kg(-1), 74 mBq L(-1) and 14.8 mBq filter(-1) were achievable for 40 x 10(-6) Kg soil, 1 x 10(-3) L tap water (or urine), and 4.5 cm diameter air-filter samples, respectively, each counted for 60 min. Data and spectra are presented showing the quality of results obtained using untreated samples obtained from the BNL Graphite Research Reactor Decommissioning Project. These samples contained Bq to MBq per gram amounts of (239,240)Pu, 241Am, and/or (234,235/238)U (as well as other beta/gamma emitters). Data and spectra are also presented for a very finely pulverized and homogeneous U.S. DOE/RESL soil reference standard (spiked with 239Pu, 241Am, and 233U) that was used to assess precision, accuracy, and reproducibility. Although this technique has its limitations, the advantages are (1) minimal sample preparation, (2) no separation chemistry required, (3) no chemical or hazardous waste generated, and (4) ability to immediately characterize and quantify alpha-emitting nuclides in most matrices. The benefits of this technique to the BNL/DOE Project Managers were rapid (1-2 d) turn-around times coupled with significant cost savings, as compared to commercial off-site analyses. PMID:12705448

  11. Influence of mathematical filters in the volume measurement of a travertine sample using high resolution x-ray microtomography

    International Nuclear Information System (INIS)

    X-ray transmission micro-computed tomography technique is a reality for characterization of pores spaces and fractures. Imaging rocks in three-dimensions this technique enables routine visualization of structures in samples, which can be spatially resolved down to the sub-micron scale. The image of micro-computed tomography is a mapping of the linear attenuation coefficient of one cross section of the sample in study. The main objective of this work is to describe the importance of using mathematical filters in the volume measurement of a travertine sample as, well as to evaluate the relevance of the filters, which were: Gaussian Blur, Unsharp Mask, Median, Uniform and Kuwahara. The results showed interesting differences both among the different filters and, mainly, in the same filter when using different radius and, also, for analysis of 2D space, as well as the resulting histograms. However the study showed that even with the evolution of the 'upgrades' of the image there is not a technique capable of solving 100% of the problems that a digital image might present and that the choice of filters must always determine the characteristics of the image emphasizing them within a specific application, always taking into consideration the image processing time. (author)

  12. Influence of mathematical filters in the volume measurement of a travertine sample using high resolution x-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Alessandra S.; Lima, Inaya; Lopes, Ricardo T., E-mail: alemachado@lin.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2013-07-01

    X-ray transmission micro-computed tomography technique is a reality for characterization of pores spaces and fractures. Imaging rocks in three-dimensions this technique enables routine visualization of structures in samples, which can be spatially resolved down to the sub-micron scale. The image of micro-computed tomography is a mapping of the linear attenuation coefficient of one cross section of the sample in study. The main objective of this work is to describe the importance of using mathematical filters in the volume measurement of a travertine sample as, well as to evaluate the relevance of the filters, which were: Gaussian Blur, Unsharp Mask, Median, Uniform and Kuwahara. The results showed interesting differences both among the different filters and, mainly, in the same filter when using different radius and, also, for analysis of 2D space, as well as the resulting histograms. However the study showed that even with the evolution of the 'upgrades' of the image there is not a technique capable of solving 100% of the problems that a digital image might present and that the choice of filters must always determine the characteristics of the image emphasizing them within a specific application, always taking into consideration the image processing time. (author)

  13. Development of a method to detect and quantify Aspergillus fumigatus conidia by quantitative PCR for environmental air samples.

    Science.gov (United States)

    McDevitt, James J; Lees, Peter S J; Merz, William G; Schwab, Kellogg J

    2004-10-01

    Exposure to Aspergillus fumigatus is linked with respiratory diseases such as asthma, invasive aspergillosis, hypersensitivity pneumonitis, and allergic bronchopulmonary aspergillosis. Molecular methods using quantitative PCR (qPCR) offer advantages over culture and optical methods for estimating human exposures to microbiological agents such as fungi. We describe an assay that uses lyticase to digest A. fumigatus conidia followed by TaqMan qPCR to quantify released DNA. This method will allow analysis of airborne A. fumigatus samples collected over extended time periods and provide a more representative assessment of chronic exposure. The method was optimized for environmental samples and incorporates: single tube sample preparation to reduce sample loss, maintain simplicity, and avoid contamination; hot start amplification to reduce non-specific primer/probe annealing; and uracil-N-glycosylase to prevent carryover contamination. An A. fumigatus internal standard was developed and used to detect PCR inhibitors potentially found in air samples. The assay detected fewer than 10 A. fumigatus conidia per qPCR reaction and quantified conidia over a 4-log10 range with high linearity (R2 >0.99) and low variability among replicate standards (CV=2.0%) in less than 4 h. The sensitivity and linearity of qPCR for conidia deposited on filters was equivalent to conidia calibration standards. A. fumigatus DNA from 8 isolates was consistently quantified using this method, while non-specific DNA from 14 common environmental fungi, including 6 other Aspergillus species, was not detected. This method provides a means of analyzing long term air samples collected on filters which may enable investigators to correlate airborne environmental A. fumigatus conidia concentrations with adverse health effects.

  14. Extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters by supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, J.B.

    1997-09-01

    Supercritical fluid extraction (SFE) using unmodified carbon dioxide has been explored as an alternative method for the extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters. HEPA filters provide the final stage of containment on many exhaust systems in US Department of Energy (DOE) facilities by preventing the escape of chemical and radioactive materials entrained in the exhausted air. The efficiency of the filters is tested by the manufacturer and DOE using dioctylphthalate (DOP), a substance regulated by the US Environmental Protection Agency under the Resource Conservation and Recovery Act. Therefore, the filters must be analyzed for semivolatile organics before disposal. Ninety-eight acid, base, and neutral semivolatile organics were spiked onto blank HEPA material and extracted using SFE, Soxhlet, automated Soxhlet, and sonication techniques. The SFE conditions were optimized using a Dionex SFE-703 instrument. Average recoveries for the 98 semivolatile compounds are 82.7% for Soxhlet, 74.0% for sonication, 70.2% for SFE, and 62.9% for Soxtec. Supercritical fluid extraction reduces the extraction solvent volume to 10--15 mL, a factor of 20--30 less than Soxhlet and more than 5 times less than Soxtec and sonication. Extraction times of 30--45 min are used compared to 16--18 h for Soxhlet extraction.

  15. Development of a modular Kalman Filter based sensor fusion algorithm for air vehicles

    OpenAIRE

    López Milla, Javier

    2013-01-01

    [ANGLÈS] Kalman Filter is nowadays one of the most used tool to perform sensor fusion in navigation environments, i.e. combine information from several different sensors to obtain the optimal navigation solution. However, there is no single algorithm for Kalman Filter and each of them must be adapted to the concrete problem. This implies that there are no two Kalman Filters that are exactly the same, complicating an objective comparison between them, mainly if implemented by different people....

  16. Thyroxine (T4) radioimmunoassay using filter paper dried blood sample: an attempt for screening of neonates for hypothyroidism

    International Nuclear Information System (INIS)

    This paper describes a sensitive but simple and less expensive method suitable for estimation of thyroxine (T4) level. Deficiency of iodine during fetal life results in neonatal hypothyroidism and critinism. Frequency of neonatal hypothyroidism is 1 in 5000 to 7000 in countries having iodine deficiency. It is therefore important to diagnose the neonatal hypothyroidism as soon as possible after birth. The estimation of thyroxine has been found to the a reliable index for diagnosis of hypothyroidism and has long been used for screening of neonatal hypothyroidism. In the present study, instead of serum sample, a 6 mm disc of filter paper containing dried blood sample was used. The test was carried out in the laboratory with 40 samples. As compared to the sensitivity of serum sample technique which is 15.19 n mol/L, the filter paper technique has the sensitivity of 17.23 n mol/L. The work revealed that the T4 concentration do not depend upon the amount of blood on the filter paper. Effect of temperature on filter paper disc was evaluated at 4o c, at 25o c and at 37o c. Results obtained showed significant variation and the best result was obtained for the sample kept at 4o c. The method is simple, rapid, less expensive and needs a small amount of blood and is, therefore, a useful technique for mass screening of neonatal hypothyroidism. 6 refs., 4 tables (author)

  17. Pemanfaatan Zeolit Alam Pahae Modifikasi sebagai Filter Uap Air pada Proses Elektrolisa

    OpenAIRE

    Zebua, Fynnisa

    2016-01-01

    The water vapour filter based on natural pahae zeolite has been succesfully manufactured by pouring the zeolit powder in 6 % H2SO4 solution and followed by heating it at 7000C, 8000C, and 9000C respectively. To improve the water vapour filter absorbility of zeolite, rind cocoa was used as filler. Whole to increase the chemical bonding between the matrik and filler, the clay was mixed with zeolite and rind cocoa. In this case, water vapour filtered come from an electrolysis process. The filter...

  18. Adjustable virtual pore-size filter for automated sample preparation using acoustic radiation force

    Energy Technology Data Exchange (ETDEWEB)

    Jung, B; Fisher, K; Ness, K; Rose, K; Mariella, R

    2008-05-22

    We present a rapid and robust size-based separation method for high throughput microfluidic devices using acoustic radiation force. We developed a finite element modeling tool to predict the two-dimensional acoustic radiation force field perpendicular to the flow direction in microfluidic devices. Here we compare the results from this model with experimental parametric studies including variations of the PZT driving frequencies and voltages as well as various particle sizes and compressidensities. These experimental parametric studies also provide insight into the development of an adjustable 'virtual' pore-size filter as well as optimal operating conditions for various microparticle sizes. We demonstrated the separation of Saccharomyces cerevisiae and MS2 bacteriophage using acoustic focusing. The acoustic radiation force did not affect the MS2 viruses, and their concentration profile remained unchanged. With optimized design of our microfluidic flow system we were able to achieve yields of > 90% for the MS2 with > 80% of the S. cerevisiae being removed in this continuous-flow sample preparation device.

  19. Standard Practice for Processing Aerospace Liquid Samples for Particulate Contamination Analysis Using Membrane Filters

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This practice covers the processing of liquids in preparation for particulate contamination analysis using membrane filters and is limited only by the liquid-to-membrane filter compatibility. 1.2 The practice covers the procedure for filtering a measured volume of liquid through a membrane filter. When this practice is used, the particulate matter will be randomly distributed on the filter surface for subsequent contamination analysis methods. 1.3 The practice describes procedures to allow handling particles in the size range between 2 and 1000 μm with minimum losses during handling. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  20. Analysis of pharmaceutical and other organic wastewater compounds in filtered and unfiltered water samples by gas chromatography/mass spectrometry

    Science.gov (United States)

    Zaugg, Steven D.; Phillips, Patrick J.; Smith, Steven G.

    2014-01-01

    Research on the effects of exposure of stream biota to complex mixtures of pharmaceuticals and other organic compounds associated with wastewater requires the development of additional analytical capabilities for these compounds in water samples. Two gas chromatography/mass spectrometry (GC/MS) analytical methods used at the U.S. Geological Survey National Water Quality Laboratory (NWQL) to analyze organic compounds associated with wastewater were adapted to include additional pharmaceutical and other organic compounds beginning in 2009. This report includes a description of method performance for 42 additional compounds for the filtered-water method (hereafter referred to as the filtered method) and 46 additional compounds for the unfiltered-water method (hereafter referred to as the unfiltered method). The method performance for the filtered method described in this report has been published for seven of these compounds; however, the addition of several other compounds to the filtered method and the addition of the compounds to the unfiltered method resulted in the need to document method performance for both of the modified methods. Most of these added compounds are pharmaceuticals or pharmaceutical degradates, although two nonpharmaceutical compounds are included in each method. The main pharmaceutical compound classes added to the two modified methods include muscle relaxants, opiates, analgesics, and sedatives. These types of compounds were added to the original filtered and unfiltered methods largely in response to the tentative identification of a wide range of pharmaceutical and other organic compounds in samples collected from wastewater-treatment plants. Filtered water samples are extracted by vacuum through disposable solid-phase cartridges that contain modified polystyrene-divinylbenzene resin. Unfiltered samples are extracted by using continuous liquid-liquid extraction with dichloromethane. The compounds of interest for filtered and unfiltered sample

  1. Microbial air-sampling equipment, part 2: experiences of compounding pharmacists.

    Science.gov (United States)

    Mixon, Bill; Cabaleiro, Joe; Latta, Kenneth S

    2008-01-01

    The most recent changes to Chapter 797 of the United States Pharmacopeia-National Formulary initiated an intense controversy about the frequency of cleanroom air sampling that is required to prevent the contamination of sterile preparations. For compounders who must purchase an air sampler to use in the cleanroom, choices abound. This article summarizes discussions from compounding pharmacists and their experiences with air sampling devices.

  2. CO2 isotope analyses using large air samples collected on intercontinental flights by the CARIBIC Boeing 767.

    Science.gov (United States)

    Assonov, S S; Brenninkmeijer, C A M; Koeppel, C; Röckmann, T

    2009-03-01

    Analytical details for 13C and 18O isotope analyses of atmospheric CO2 in large air samples are given. The large air samples of nominally 300 L were collected during the passenger aircraft-based atmospheric chemistry research project CARIBIC and analyzed for a large number of trace gases and isotopic composition. In the laboratory, an ultra-pure and high efficiency extraction system and high-quality isotope ratio mass spectrometry were used. Because direct comparison with other laboratories was practically impossible, the extraction and measurement procedures were tested in considerable detail. Extracted CO2 was measured twice vs. two different working reference CO2 gases of different isotopic composition. The two data sets agree well and their distributions can be used to evaluate analytical errors due to isotope measurement, ion corrections, internal calibration consistency, etc. The calibration itself is based on NBS-19 and also verified using isotope analyses on pure CO2 gases (NIST Reference Materials (RMs) and NARCIS CO2 gases). The major problem encountered could be attributed to CO2-water exchange in the air sampling cylinders. This exchange decreased over the years. To exclude artefacts due to such isotopic exchange, the data were filtered to reject negative delta18O(CO2) values. Examples of the results are given. PMID:19219897

  3. Qualitative analysis by X ray fluorescence of impurities in materials used as air filters; Analisis cualitativo por fluorescencia de rayos X de impurezas en materiales utilizados como filtros de aire

    Energy Technology Data Exchange (ETDEWEB)

    Lartigue G, J; Munoz M, G; Navarrete T, M [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    1995-06-01

    A qualitative analysis of impurities in 5 materials commonly used as air filters was performed with 2 aims: to compare them, in regard to their impurities and to set a methodology to identify spectroscopically, in a short time (1000 seconds), those impurities in order to subtract the blanks signal from that one generated by the collected sample. Some papers on air filters impurities (cellulose, polycarbonate and glass fiber) were found in literature. In one case, the analysis was performed by energy-dispersive X ray fluorescence, tube generated method. In this work it was employed the same method but a radioisotope (Cd-109) was used as primary source. This was applied to 2 of the above mentioned materials as well as to nylon, teflon and quartz. The glass fiber filter had the highest impurity level: Ca, Ba, Pb, Zn, Sr, Rb, and Fe (0.5 {mu}gFe/cm{sup 2}, measured by Atomic Absorption Spectroscopy). The teflon filter had the lowest impurity level. The developed procedure is fast, precise and reproducible and it may be applied also to wastewaters filters. [Spanish] Se realizo el analisis cualitativo de impurezas en cinco materiales comunmente utilizados como filtros de aire, con dos propositos: compararlos en base a sus impurezas y establecer una metodologia que permitiera, en muy corto tiempo (1000 segundos), identificar espectroscopicamente las impurezas a fin de restar la senal del blanco de aquella que genera eventualmente la muestra. En la bibliografia se encontraron algunas publicaciones acerca de impurezas en filtros de aire (celulosa, pollicarbonato y fibra de vidrio), determinadas principalmente por Absorcion Atomica. En un caso, tal determinacion se realizo por Fluorescencia de Rayos X generados en tubo de descargas y detectados por dispersion de energia. En este trabajo se empleo el mismo metodo de Fluorescencia de Rayos X detectados por dispersion de energia pero generados por un radioisotopo (Cd-109) y se aplico a dos de los tres materiales antes

  4. A study of the oxidation hydrolysis of CsI radioaerosols in a steam-air medium using filtering units

    International Nuclear Information System (INIS)

    A study of the oxidation hydrolysis of radioaerosols is an issue of acute importance from both scientific and practical points of view. This can be explained by the facts that there is currently virtually no experimental data on this process and that the problem of the localization of CsI radioaerosols during accidents at nuclear power enterprises still remains unsolved. We carried out a study of the oxidation hydrolysis of 137CS131I radioaerosols in a steam-vapor medium during their localization on a column with filtering units, specifically: (1) 'Bekipor WB12' metal fiber (Cr-Ni-Mo alloy, fiber thickness ∼12 μm, density ∼0.05 g/cm3, specific surface area ∼450 cm2/g; (2) spiral filtering unit made of a wire measuring 8.0 m in length and 0.6 mm in diameter (working area parameters: length ∼115 mm, diameter ∼14 mm, and specific surface area ∼0.01 cm2/g; (3) 'TRUMEM stainless steel membrane filter (diameter ∼20 mm, thickness 0.2 mm, specific surface area ∼5000 cm2/g, pore size ∼2 μm; (4) three-layer de-ashed paper filter known as 'white band' (pore diameter 3.5 μm and specific surface ∼8000 cm2/g). The results of the study allowed us to suggest that the sublimation of 137CS131I from a platinum heater under specific conditions can lead to the formation of the following compounds 137CsOH, 137CS131I - 137CsOH, 137CS131I3, and 131I2. The oxidation hydrolysis of 13lCS131I radioaerosols and the interaction of hydrolysis products with the surfaces of the metal and paper filtering units took place under the following conditions: air-flow temperature 403-423 Κ, steam content in the air flow about 3-4 to 90 vol.%, and the linear velocity of the flow in the sorption column from 6 to 24 cm/s. The filtering units managed to localize from ∼5 to ∼98 % of the initial amount of 137CS131I (0:17-70 mg) supplied to the filtering system, which depended on the filtering material, the size of its inner surface, and the conditions of the experiment.

  5. Air filters and air cleaners: Rostrum by the American Academy of Allergy, Asthma & Immunology Indoor Allergen Committee

    OpenAIRE

    Sublett, James L.; Seltzer, James; Burkhead, Robert; Williams, P. Brock; Wedner, H. James; Phipatanakul, Wanda

    2009-01-01

    The allergist is generally recognized as possessing the greatest expertise in relating airborne contaminants to respiratory health, both atopic and nonatopic. Consequently, allergists are most often asked for their professional opinions regarding the appropriate use of air-cleaning equipment. This rostrum serves as a resource for the allergist and other health care professionals seeking a better understanding of air filtration.

  6. How does an fMRI voxel sample the neuronal activity pattern: compact-kernel or complex spatiotemporal filter?

    Science.gov (United States)

    Kriegeskorte, Nikolaus; Cusack, Rhodri; Bandettini, Peter

    2010-02-01

    Recent studies suggested that fMRI voxel patterns can convey information represented in columnar-scale neuronal population codes, even when spatial resolution is insufficient to directly image the patterns of columnar selectivity (Kamitani and Tong, 2005; Haynes and Rees, 2005). Sensitivity to subvoxel-scale pattern information, or "fMRI hyperacuity," would greatly enhance the power of fMRI when combined with pattern information analysis techniques (Kriegeskorte and Bandettini, 2007). An individual voxel might weakly reflect columnar-level information if the columns within its boundaries constituted a slightly unbalanced sample of columnar selectivities (Kamitani and Tong, 2005), providing a possible mechanism for fMRI hyperacuity. However, Op de Beeck (2009) suggests that a coarse-scale neuronal organization rather than fMRI hyperacuity may explain the presence of the information in the fMRI patterns. Here we argue (a) that the present evidence does not rule out fMRI hyperacuity, (b) that the mechanism originally suggested for fMRI hyperacuity (biased sampling by averaging within each voxel's boundaries; Kamitani and Tong, 2005) will only produce very weak sensitivity to fine-grained pattern information, and (c) that an alternative mechanism (voxel as complex spatiotemporal filter) is physiologically more accurate and promises stronger sensitivity to fine-grained pattern information: We know that each voxel samples the neuronal activity pattern through a unique fine-grained structure of venous vessels that supply its blood oxygen level-dependent signal. At the simplest level, the drainage domain of a venous vessel may sample the neuronal pattern with a selectivity bias (Gardner, 2009; Shmuel et al., 2009). Beyond biased drainage domains, we illustrate with a simple simulation how temporal properties of the hemodynamics (e.g., the speed of the blood in the capillary bed) can shape spatial properties of a voxel's filter (e.g., how finely structured it is). This

  7. Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang (China)

    OpenAIRE

    Taketani, F.; Y. Kanaya; P. Pochanart; Liu, Y; Li, J.; K. Okuzawa; K. Kawamura; Z. Wang; H. Akimoto

    2012-01-01

    HO2 uptake coefficients for ambient aerosol particles, collected on quartz fiber filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol parti...

  8. Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang, China

    OpenAIRE

    H. Akimoto; Z. Wang; K. Okuzawa; K. Kawamura; Li, J.; Liu, Y; P. Pochanart; Taketani, F.; Y. Kanaya

    2012-01-01

    HO2 uptake coefficients for ambient aerosol particles, collected on quartz filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. ...

  9. Filter-based assay for Escherichia coli in aqueous samples using bacteriophage-based amplification.

    Science.gov (United States)

    Derda, Ratmir; Lockett, Matthew R; Tang, Sindy K Y; Fuller, Renee C; Maxwell, E Jane; Breiten, Benjamin; Cuddemi, Christine A; Ozdogan, Aysegul; Whitesides, George M

    2013-08-01

    This paper describes a method to detect the presence of bacteria in aqueous samples, based on the capture of bacteria on a syringe filter, and the infection of targeted bacterial species with a bacteriophage (phage). The use of phage as a reagent provides two opportunities for signal amplification: (i) the replication of phage inside a live bacterial host and (ii) the delivery and expression of the complementing gene that turns on enzymatic activity and produces a colored or fluorescent product. Here we demonstrate a phage-based amplification scheme with an M13KE phage that delivers a small peptide motif to an F(+), α-complementing strain of Escherichia coli K12, which expresses the ω-domain of β-galactosidase (β-gal). The result of this complementation-an active form of β-gal-was detected colorimetrically, and the high level of expression of the ω-domain of β-gal in the model K12 strains allowed us to detect, on average, five colony-forming units (CFUs) of this strain in 1 L of water with an overnight culture-based assay. We also detected 50 CFUs of the model K12 strain in 1 L of water (or 10 mL of orange juice, or 10 mL of skim milk) in less than 4 h with a solution-based assay with visual readout. The solution-based assay does not require specialized equipment or access to a laboratory, and is more rapid than existing tests that are suitable for use at the point of access. This method could potentially be extended to detect many different bacteria with bacteriophages that deliver genes encoding a full-length enzyme that is not natively expressed in the target bacteria.

  10. Comparison of stationary and personal air sampling with an air dispersion model for children's ambient exposure to manganese.

    Science.gov (United States)

    Fulk, Florence; Haynes, Erin N; Hilbert, Timothy J; Brown, David; Petersen, Dan; Reponen, Tiina

    2016-09-01

    Manganese (Mn) is ubiquitous in the environment and essential for normal growth and development, yet excessive exposure can lead to impairments in neurological function. This study modeled ambient Mn concentrations as an alternative to stationary and personal air sampling to assess exposure for children enrolled in the Communities Actively Researching Exposure Study in Marietta, OH. Ambient air Mn concentration values were modeled using US Environmental Protection Agency's Air Dispersion Model AERMOD based on emissions from the ferromanganese refinery located in Marietta. Modeled Mn concentrations were compared with Mn concentrations from a nearby stationary air monitor. The Index of Agreement for modeled versus monitored data was 0.34 (48 h levels) and 0.79 (monthly levels). Fractional bias was 0.026 for 48 h levels and -0.019 for monthly levels. The ratio of modeled ambient air Mn to measured ambient air Mn at the annual time scale was 0.94. Modeled values were also time matched to personal air samples for 19 children. The modeled values explained a greater degree of variability in personal exposures compared with time-weighted distance from the emission source. Based on these results modeled Mn concentrations provided a suitable approach for assessing airborne Mn exposure in this cohort. PMID:27168393

  11. Comparison of stationary and personal air sampling with an air dispersion model for children's ambient exposure to manganese.

    Science.gov (United States)

    Fulk, Florence; Haynes, Erin N; Hilbert, Timothy J; Brown, David; Petersen, Dan; Reponen, Tiina

    2016-09-01

    Manganese (Mn) is ubiquitous in the environment and essential for normal growth and development, yet excessive exposure can lead to impairments in neurological function. This study modeled ambient Mn concentrations as an alternative to stationary and personal air sampling to assess exposure for children enrolled in the Communities Actively Researching Exposure Study in Marietta, OH. Ambient air Mn concentration values were modeled using US Environmental Protection Agency's Air Dispersion Model AERMOD based on emissions from the ferromanganese refinery located in Marietta. Modeled Mn concentrations were compared with Mn concentrations from a nearby stationary air monitor. The Index of Agreement for modeled versus monitored data was 0.34 (48 h levels) and 0.79 (monthly levels). Fractional bias was 0.026 for 48 h levels and -0.019 for monthly levels. The ratio of modeled ambient air Mn to measured ambient air Mn at the annual time scale was 0.94. Modeled values were also time matched to personal air samples for 19 children. The modeled values explained a greater degree of variability in personal exposures compared with time-weighted distance from the emission source. Based on these results modeled Mn concentrations provided a suitable approach for assessing airborne Mn exposure in this cohort.

  12. The effect of electrostatic force on air filtration by polypropylene filter media

    International Nuclear Information System (INIS)

    In this paper, the effect of irradiation with 60Co on the efficiency and strength of the polypropylene filter media is mainly researched. The charge density of polypropylene fibre is evaluated by radiation discharge method. Based on isolated cylinder model, the efficiency of the polypropylene filter media, which takes account of the effect of impaction, interception, diffusion and electrostatic, is calculated. A better agreement between theoretical analysis and experimental results is obtained. The results indicate that electrostatic force is the most important factor in solid aerosol filtration of the polypropylene filter media

  13. The impact of air pollution from used ventilation filters on human comfort and health

    DEFF Research Database (Denmark)

    Clausen, Geo; Alm, O.; Fanger, Povl Ole

    2002-01-01

    The comfort and health of 30 women was studied during 4 hours´ exposure in an experimental room with either a used or a new filter present in the ventilation system. All other environmental parameters were kept constant. The presence of the used filter in the ventilation system had a significant ...... adverse impact on several perceptions and symptoms, both immediately upon entering the office and throughout the exposure period. None of the perceptions or symptoms were better when the used filter was in the system....

  14. Development of glass-fiber high-efficiency particulate air filters of high structural strength on the basis of the establishment of failure mechanisms

    International Nuclear Information System (INIS)

    Practical experience from routine operation in nuclear installations as well as extensive bench and laboratory testing proved the structural limits of HEPA filters to be very low thus demonstrating the need for improvement of their structural strength. Detailed analysis of the courses and modes of filter failure under the challenge of dry air at high velocities and ambient temperature, together with additional measurements, allowed the establishment of the dominating mechanisms of filter failure. Based on this information, the following three options for effective and economical improvements in filter structural limits exist: (1) an increase in the tensile strength of the filter medium; (2) an increase in the stability of the pack to prevent the swelling of individual pleats; and (3) an increase in the area moment of inertia of the separators and a decrease in the sharpness of their edges. By using a reinforced glass fiber filter medium, the structural strength of standard size HEPA filters was increased to 31 kPa with dry air and beyond 10 kPa with air at high humidity. Prototype filters built with standard glass-fiber media and separators with inclined corrugations exhibited failure pressures of approximately 50 kPa under high velocity airflows. The combination of both types of improvements, together with other measures, will soon lead to even higher HEPA-filter structural strength

  15. imFASP: An integrated approach combining in-situ filter-aided sample pretreatment with microwave-assisted protein digestion for fast and efficient proteome sample preparation.

    Science.gov (United States)

    Zhao, Qun; Fang, Fei; Wu, Ci; Wu, Qi; Liang, Yu; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-03-17

    An integrated sample preparation method, termed "imFASP", which combined in-situ filter-aided sample pretreatment and microwave-assisted trypsin digestion, was developed for preparation of microgram and even nanogram amounts of complex protein samples with high efficiency in 1 h. For imFASP method, proteins dissolved in 8 M urea were loaded onto a filter device with molecular weight cut off (MWCO) as 10 kDa, followed by in-situ protein preconcentration, denaturation, reduction, alkylation, and microwave-assisted tryptic digestion. Compared with traditional in-solution sample preparation method, imFASP method generated more protein and peptide identifications (IDs) from preparation of 45 μg Escherichia coli protein sample due to the higher efficiency, and the sample preparation throughput was significantly improved by 14 times (1 h vs. 15 h). More importantly, when the starting amounts of E. coli cell lysate decreased to nanogram level (50-500 ng), the protein and peptide identified by imFASP method were improved at least 30% and 44%, compared with traditional in-solution preparation method, suggesting dramatically higher peptide recovery of imFASP method for trace amounts of complex proteome samples. All these results demonstrate that the imFASP method developed here is of high potential for high efficient and high throughput preparation of trace amounts of complex proteome samples. PMID:26920773

  16. Penentuan Nilai pH dan Alkalinitas pada Air Filter HM. Yamin di Laboratorium PDAM Tirtanadi Medan

    OpenAIRE

    Ramahdani

    2015-01-01

    Water is a chemical compound that is essential for the process of life, a lot of water is used for cooking, washing, bathing, and so on. In the provision of drinking water, and the pH value of the water alkalintas is one factor to be considered in the drinking water quality standards. Experiment goal is to determine the pH and alkalinity of the water filter HM.Yamin used as drinking water. Sample taken from the water faucet filter derived from the production wellbore Tritanadi PDAM Medan. ...

  17. Impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls generation

    Science.gov (United States)

    Lin, Chi-Chi; Chen, Hsuan-Yu

    2014-06-01

    This study aims at detecting ozone removal rates and corresponding carbonyls generated by ozone reaction with HVAC filters from various building, i.e., shopping mall, school, and office building. Studies were conducted in a small-scale environmental chamber. By examining dust properties including organic carbon proportion and specific surface area of dusts adsorbed on filters along with ozone removal rates and carbonyls generation rate, the relationship among dust properties, ozone removal rates, and carbonyls generation was identified. The results indicate a well-defined positive correlation between ozone removal efficiency and carbonyls generation on filters, as well as a positive correlation among the mass of organic carbon on filters, ozone removal efficiency and carbonyls generations.

  18. Sample and injection manifolds used to in-place test of nuclear air-cleaning system

    International Nuclear Information System (INIS)

    Objective: According to the regulations of nuclear safety rules and related standards, in-place test of the nuclear air-cleaning systems should be carried out before and during operation of the nuclear facilities, which ensure them to be in good condition. In some special conditions, the use of sample and injection manifolds is required to make the test tracer and ventilating duct air fully mixed, so as to get the on-spot typical sample. Methods: This paper introduces the technology and application of the sample and injection manifolds in nuclear air-cleaning system. Results: Multi point injection and multi point sampling technology as an effective experimental method, has been used in a of domestic and international nuclear facilities. Conclusion: The technology solved the problem of uniformly of on-spot injection and sampling,which plays an important role in objectively evaluating the function of nuclear air-cleaning system. (authors)

  19. Summary of efficiency testing of standard and high-capacity high-efficiency particulate air filters subjected to simulated tornado depressurization and explosive shock waves

    International Nuclear Information System (INIS)

    Pressure transients in nuclear facility air cleaning systems can originate from natural phenomena such as tornadoes or from accident-induced explosive blast waves. This study was concerned with the effective efficiency of high-efficiency particulate air (HEPA) filters during pressure surges resulting from simulated tornado and explosion transients. The primary objective of the study was to examine filter efficiencies at pressure levels below the point of structural failure. Both standard and high-capacity 0.61-m by 0.61-m HEPA filters were evaluated, as were several 0.2-m by 0.2-m HEPA filters. For a particular manufacturer, the material release when subjected to tornado transients is the same (per unit area) for both the 0.2-m by 0.2-m and the 0.61-m by 0.61-m filters. For tornado transients, the material release was on the order of micrograms per square meter. When subjecting clean HEPA filters to simulated tornado transients with aerosol entrained in the pressure pulse, all filters tested showed a degradation of filter efficiency. For explosive transients, the material release from preloaded high-capacity filters was as much as 340 g. When preloaded high-capacity filters were subjected to shock waves approximately 50% of the structural limit level, 1 to 2 mg of particulate was released

  20. PRODUCTION OF ACTIVATED CHARCOAL SAMPLER TUBES FOR SAMPLING AIR CONTAMINANTS

    OpenAIRE

    P Nassiri; F Golbabaie; S. Nasseri; M. Mahmoodi; K. Mehrain

    1988-01-01

    The importance of the use of activated charcoal tubes for sampling gases and vapors is very well-known. For producing these tubes in the country, their production started in the laboratory of the department of occupation al health using activated charcoal, polyurethane foam and glass wool and consequently two types of foamed and foamless tubes were produced. To investigate the quality of the raw materials used, 186 tubes were exposed to various proportions of solutions of different volumes of...

  1. PRODUCTION OF ACTIVATED CHARCOAL SAMPLER TUBES FOR SAMPLING AIR CONTAMINANTS

    Directory of Open Access Journals (Sweden)

    P.Nassiri

    1988-08-01

    Full Text Available The importance of the use of activated charcoal tubes for sampling gases and vapors is very well-known. For producing these tubes in the country, their production started in the laboratory of the department of occupation al health using activated charcoal, polyurethane foam and glass wool and consequently two types of foamed and foamless tubes were produced. To investigate the quality of the raw materials used, 186 tubes were exposed to various proportions of solutions of different volumes of known percentages of four compounds of benzene, toluene, O-xylene and P-xlene. The adsorption of various parts of sampler tubes was done by a chemical method using CS2 and the final analysis was done by gas chromatography. The results obtained show that the amount of the above named compounds adsorbed by glass wool and foam in comparison to the activated charcoal isn’t significant (respectively P<0.001 & P,0.05. Also the experiments don’s show any significant differences between the total amount of adsorbed chemicals by charcoal in the back-up layer and the sample layer of the foamed tube and the amount adsorbed in the foamless tube, when treated with various compounds (P,0.001. Considering the equal adsorption of both types of tubes and the advantage of foamed tubes in controlling the time duration and the flow rate of sampling, the foamed type was recommended for production and use.

  2. Investigation into Alternative Sample Preparation Techniques for the Determination of Heavy Metals in Stationary Source Emission Samples Collected on Quartz Filters

    Directory of Open Access Journals (Sweden)

    Sharon L. Goddard

    2014-11-01

    Full Text Available Monitoring stationary source emissions for heavy metals generally requires the use of quartz filters to collect samples because of the high temperature and high moisture sampling environment. The documentary standard method sample preparation technique in Europe, EN 14385, uses digestion in hydrofluoric acid and nitric acid (HF/HNO3 followed by complexing with boric acid (H3BO3 prior to analysis. However, the use of this method presents a number of problems, including significant instrumental drift during analysis caused by the matrix components, often leading to instrument breakdown and downtime for repairs, as well as posing significant health and safety risks. The aim of this work was to develop an alternative sample preparation technique for emissions samples on quartz filters. The alternative techniques considered were: (i acid digestion in a fluoroboric acid (HBF4 and HNO3 mixture and (ii acid extraction in an aqua regia (AR mixture (HCl and HNO3. Assessment of the effectiveness of these options included determination of interferences and signal drift, as well as validating the different methods by measurement of matrix certified reference materials (CRMs, and comparing the results obtained from real test samples and sample blanks to determine limits of detection. The results showed that the HBF4/HNO3 mixture provides the most viable alternative to the documentary standard preparation technique.

  3. Air quality. How to give it back its original purity? The proliferation of air cleansers. Filters must be changed regularly. Measurement of the filtering efficiency of air treatment systems. The air treatment plants on the way of certification. Essential oils in a high building; Qualite de l'air. Comment lui rendre sa purete originelle? La proliferation des purificateurs d'air. Il faut changer les filtres regulierement. Mesure de l'efficacite de filtration des systemes de traitement d'air. Les centrales de traitement d'air sur la voie de la certification. Des huiles essentielles dans un immeuble de grande hauteur

    Energy Technology Data Exchange (ETDEWEB)

    Grumel, N.

    2000-07-01

    Outside air is polluted while the ambient indoor air is saturated with microorganisms. Inside buildings, the aeraulic networks are the link between both environments and the privileged place to clean the air using filtering systems. However, the notion of air quality is still badly perceived by owners, in particular in tertiary buildings. In France, efforts have to be made on the maintenance of aeraulic networks by hygiene specialists. Air quality inside buildings must be taken into consideration using communication and regulations. This dossier takes stock of the problem of air quality and of the available means to ensure a good air quality inside residential and tertiary buildings. The maintenance of air filters in one of the key points. It should be integrated in the general maintenance concept of buildings. The dossier includes a study of the in-situ measurement of the filtering efficiency of air treatment systems. This method is described in the Eurovent recommendation 4/10 of 1996. It has been experimented by the French technical centre of aeraulic and thermal industries (Cetiat) and the results are reported in the study. The performances of air treatment plants are now certified by Eurovent. This European organization has defined a program of tests which is conformable with the European EN 1886 and EN 13053 European standards. Finally, a new protocol of air decontamination based on the micronizing of essential oils in the aeraulic network of a 29 floors building is presented. (J.S.)

  4. Suitability of Semiconductor Heterostructure over SiO2-Air Composition for One-Dimensional Photonic Crystal based Bandpass Filter

    Directory of Open Access Journals (Sweden)

    Arka Karmakar

    2013-05-01

    Full Text Available Bandpass filter characteristics is numerically computed for semiconductor heterostructure based onedimensional photonic crystal at different optical wavelengths by varying the structural parameters taking GaAs/AlxGa1-xAs as a suitable composition subject to normal incidence of electromagnetic wave. Transfer matrix technique is used for numerical analysis. Results are compared with conventionally used SiO2-air material system and significance improvements are observed at few desired spectra. Heterostructure provides larger passbandwidth with almost negligible ripple than conventional material system at 1330 nm or 1550 nm, which is required for present day optical communication network. Efficient tuning can be achieved by varying different layer dimensions for the preferred material composition which effectively changes the filter bandwidth in either side of the central wavelength, but it cost generation of ripples for the conventional system.

  5. Modelling of air flows in pleated filters and of their clogging by solid particles; Modelisation des ecoulements d'air et du colmatage des filtres plisses par des aerosols solides

    Energy Technology Data Exchange (ETDEWEB)

    Del Fabbro, L

    2002-07-01

    The devices of air cleaning against particles are widely spread in various branches of industry: nuclear, motor, food, electronic,...; among these devices, numerous are constituted by pleated porous media to increase the surface of filtration and thus to reduce the pressure drop, for given air flow. The objective of our work is to compensate a lack evident of knowledge on the evolution of the pressure drop of pleated filter during the clogging and to deduct a modelling from it, on the basis of experiments concerning industrial filters of nuclear and car types. The obtained model is a function of characteristics of the filtering medium and pleats, of the characteristics of solid particles deposited on the filter, of the mass of particles and of the aeraulic conditions of air flow. It also depends on data on the clogging of flat filters of equivalent medium. To elaborate this model of pressure drop, an initial stage was carried out in order to characterize, experimentally and numerically, the pressure drop and the distribution of air flow in clean pleated filters of nuclear (high efficiency particulate air filter, in fiberglasses) and car (mean efficiency filter, in fibers of cellulose) types. The numerical model allowed to understand the fundamental role played by the aeraulic resistance of the filtering medium. From an non-dimensional approach, we established a semi-empirical model of pressure drop for a clean pleated filter valid for both studied types of medium; this model is used of first base for the development of the final model of clogging. The study of the clogging of the filters showed the complexity of the phenomenon dependent mainly on a reduction of the surface of filtration. This observation brings us to propose a clogging of pleated filters in three phases. Both first phases are similar in those observed for flat filters, while last phase corresponds to a reduction of the surface of filtration and leads a strong increase of the filter pressure drop

  6. Dispersion modeling of selected PAHs in urban air: A new approach combining dispersion model with GIS and passive air sampling

    Science.gov (United States)

    Sáňka, Ondřej; Melymuk, Lisa; Čupr, Pavel; Dvorská, Alice; Klánová, Jana

    2014-10-01

    This study introduces a new combined air concentration measurement and modeling approach that we propose can be useful in medium and long term air quality assessment. A dispersion study was carried out for four high molecular weight polycyclic aromatic hydrocarbons (PAHs) in an urban area with industrial, traffic and domestic heating sources. A geographic information system (GIS) was used both for processing of input data as well as visualization of the modeling results. The outcomes of the dispersion model were compared to the results of passive air sampling (PAS). Despite discrepancies between measured and modeled concentrations, an approach combining the two techniques is promising for future air quality assessment. Differences between measured and modeled concentrations, in particular when measured values exceed the modeled concentrations, are indicative of undocumented, sporadic pollutant sources. Thus, these differences can also be useful for assessing and refining emission inventories.

  7. Sampling strategies for the analysis of reactive low-molecular weight compounds in air

    NARCIS (Netherlands)

    Henneken, Hartmut

    2006-01-01

    Within this thesis, new sampling and analysis strategies for the determination of airborne workplace contaminants have been developed. Special focus has been directed towards the development of air sampling methods that involve diffusive sampling. In an introductory overview, the current state-of-th

  8. Green Ocean Amazon 2014/15 High-Volume Filter Sampling: Atmospheric Particulate Matter of an Amazon Tropical City and its Relationship to Population Health Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Machado, C. M. [Federal Univ. of Amazonas (Brazil); Santos, Erickson O. [Federal Univ. of Amazonas (Brazil); Fernandes, Karenn S. [Federal Univ. of Amazonas (Brazil); Neto, J. L. [Federal Univ. of Amazonas (Brazil); Souza, Rodrigo A. [Univ. of the State of Amazonas (Brazil)

    2016-08-01

    Manaus, the capital of the Brazilian state of Amazonas, is developing very rapidly. Its pollution plume contains aerosols from fossil fuel combustion mainly due to vehicular emission, industrial activity, and a thermal power plant. Soil resuspension is probably a secondary source of atmospheric particles. The plume transports from Manaus to the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility ARM site at Manacapuru urban pollutants as well as pollutants from pottery factories along the route of the plume. Considering the effects of particulate matter on health, atmospheric particulate matter was evaluated at this site as part of the ARM Facility’s Green Ocean Amazon 2014/15 (GoAmazon 2014/15) field campaign. Aerosol or particulate matter (PM) is typically defined by size, with the smaller particles having more health impact. Total suspended particulate (TSP) are particles smaller than 100 μm; particles smaller than 2.5 μm are called PM2.5. In this work, the PM2.5 levels were obtained from March to December of 2015, totaling 34 samples and TSP levels from October to December of 2015, totaling 17 samples. Sampling was conducted with PM2.5 and TSP high-volume samplers using quartz filters (Figure 1). Filters were stored during 24 hours in a room with temperature (21,1ºC) and humidity (44,3 %) control, in order to do gravimetric analyses by weighing before and after sampling. This procedure followed the recommendations of the Brazilian Association for Technical Standards local norm (NBR 9547:1997). Mass concentrations of particulate matter were obtained from the ratio between the weighted sample and the volume of air collected. Defining a relationship between particulate matter (PM2.5 and TSP) and respiratory diseases of the local population is an important goal of this project, since no information exists on that topic.

  9. Investigation of total and hexavalent chromium in filtered and unfiltered groundwater samples at the Tucson International Airport Superfund Site

    Science.gov (United States)

    Tillman, Fred; McCleskey, R. Blaine; Hermosillo, Edyth

    2016-01-01

    Potential health effects from hexavalent chromium in groundwater have recently become a concern to regulators at the Tucson International Airport Area Superfund site. In 2016, the U.S. Geological Survey sampled 46 wells in the area to characterize the nature and extent of chromium in groundwater, to understand what proportion of total chromium is in the hexavalent state, and to determine if substantial differences are present between filtered and unfiltered chromium concentrations. Results indicate detectable chromium concentrations in all wells, over 75 % of total chromium is in the hexavalent state in a majority of wells, and filtered and unfiltered results differ substantially in only a few high-turbidity total chromium samples.

  10. LARGE SAMPLE PROPERTIES OF THE SIR IN CDMA WITH MATCHED FILTER RECEIVERS

    Institute of Scientific and Technical Information of China (English)

    PAN GUANGMING; MIAO BAIQI; ZHU CHUNHUA

    2005-01-01

    The output signal-to-interference (SIR) of conventional matched filter receiver in random environment is considered. When the number of users and the spreading factors tend to infinity with their ratio fixed, the convergence of SIR is showed to be with probability one under finite fourth.moment of the spreading sequences. The asymptotic distribution of the SIR is also obtained.

  11. Application of a high-efficiency cabin air filter for simultaneous mitigation of ultrafine particle and carbon dioxide exposures inside passenger vehicles.

    Science.gov (United States)

    Lee, Eon S; Zhu, Yifang

    2014-02-18

    Modern passenger vehicles are commonly equipped with cabin air filters but their filtration efficiency for ultrafine particle (UFP) is rather low. Although setting the vehicle ventilation system to recirculation (RC) mode can reduce in-cabin UFPs by ∼ 90%, passenger-exhaled carbon dioxide (CO2) can quickly accumulate inside the cabin. Using outdoor air (OA) mode instead can provide sufficient air exchange to prevent CO2 buildup, but in-cabin UFP concentrations would increase. To overcome this dilemma, we developed a simultaneous mitigation method for UFP and CO2 using high-efficiency cabin air (HECA) filtration in OA mode. Concentrations of UFP and other air pollutants were simultaneously monitored in and out of 12 different vehicles under 3 driving conditions: stationary, on local roadways, and on freeways. Under each experimental condition, data were collected with no filter, in-use original equipment manufacturer (OEM) filter, and two types of HECA filters. The HECA filters offered an average in-cabin UFP reduction of 93%, much higher than the OEM filters (∼ 50% on average). Throughout the measurements, the in-cabin CO2 concentration remained in the range of 620-930 ppm, significantly lower than the typical level of 2500-4000 ppm observed in the RC mode. PMID:24471775

  12. Analysis of pharmaceutical and other organic wastewater compounds in filtered and unfiltered water samples by gas chromatography/mass spectrometry

    Science.gov (United States)

    Zaugg, Steven D.; Phillips, Patrick J.; Smith, Steven G.

    2014-01-01

    Research on the effects of exposure of stream biota to complex mixtures of pharmaceuticals and other organic compounds associated with wastewater requires the development of additional analytical capabilities for these compounds in water samples. Two gas chromatography/mass spectrometry (GC/MS) analytical methods used at the U.S. Geological Survey National Water Quality Laboratory (NWQL) to analyze organic compounds associated with wastewater were adapted to include additional pharmaceutical and other organic compounds beginning in 2009. This report includes a description of method performance for 42 additional compounds for the filtered-water method (hereafter referred to as the filtered method) and 46 additional compounds for the unfiltered-water method (hereafter referred to as the unfiltered method). The method performance for the filtered method described in this report has been published for seven of these compounds; however, the addition of several other compounds to the filtered method and the addition of the compounds to the unfiltered method resulted in the need to document method performance for both of the modified methods. Most of these added compounds are pharmaceuticals or pharmaceutical degradates, although two nonpharmaceutical compounds are included in each method. The main pharmaceutical compound classes added to the two modified methods include muscle relaxants, opiates, analgesics, and sedatives. These types of compounds were added to the original filtered and unfiltered methods largely in response to the tentative identification of a wide range of pharmaceutical and other organic compounds in samples collected from wastewater-treatment plants. Filtered water samples are extracted by vacuum through disposable solid-phase cartridges that contain modified polystyrene-divinylbenzene resin. Unfiltered samples are extracted by using continuous liquid-liquid extraction with dichloromethane. The compounds of interest for filtered and unfiltered sample

  13. Stereoisomer composition of the chiral UV filter 4-methylbenzylidene camphor in environmental samples.

    Science.gov (United States)

    Buser, Hans-Rudolf; Müller, Markus D; Balmer, Marianne E; Poiger, Thomas; Buerge, Ignaz J

    2005-05-01

    4-Methylbenzylidene camphor (4-MBC) is an important organic UV filter used in many personal care products such as sunscreens and cosmetics. After use, 4-MBC may enter the aquatic environment due to its release from skin during recreational activities (swimming, bathing) and from personal hygiene measures (washing, laundering of cloths) via wastewater treatment plants (WWTPs). In fact, 4-MBC has been detected in wastewater, in surface waters, and even in fish. 4-MBC can exist as distinct cis-(Z)- and trans-(E)-isomers, both of which are chiral. Despite the fact that stereoisomers often show a different biological behavior, the stereochemistry of 4-MBC has hardly ever been considered in environmental or biological studies. In this study, enantioselective gas chromatography-mass spectrometry (GC-MS) was used to determine the stereoisomer composition of 4-MBC. For stereoisomer assignment, the pure enantiomers of (E)-4-MBC were synthesized from (+)- and (-)-camphor. The photochemical isomerization (sunlight) of these (E)-isomers to the corresponding (Z)-isomers eventually allowed the configurational assignment of all four stereoisomers of 4-MBC. In a technical material and in a major brand sun lotion, 4-MBC was shown to consist entirely (>99%) of (E)-isomers and to be racemic (R/S, 1.00 +/- 0.02). Wastewater showed the presence of both (E)- and (Z)-4-MBC with a clear excess of (E)-isomers (E > Z). Untreated wastewater showed a nearly racemic composition (R/S= 0.95-1.09), suggesting that most if not all commercial 4-MBC is racemic. Treated wastewater indicated some excess of (R)- or (S)-stereoisomers (R/S, 0.89-1.17), likely as a result of some enantioselective (bio)degradation in WWTPs. Residues of 4-MBC in lakes and in a river with inputs from WWTPs and/or recreational activities consisted mainly of (E)-4-MBC and, with exception of one lake (Greifensee), showed a small enantiomer excess (R/S, 1.04-1.16). In Greifensee, 4-MBC showed a higher enantiomer excess (R/S, 1

  14. ANALYSIS OF EFFECT OF APPROXIMATING OUTPUT SAMPLES USING RANDOM SUB-SAMPLING OF INPUT FOR COMPUTATION REDUCTION IN FILTERING OPERATION

    Directory of Open Access Journals (Sweden)

    AMANPREET SINGH

    2006-12-01

    Full Text Available Communication plays a significant role in today’s life. Integration of computing and communicating devices, wide-spread internet access through World Wide Web (WWW, and wireless links are an increasing demand for mobile cellular services at the consumer end, so it has led to new signal processing technologies. Signal processing and communications are tightly inter-woven and immensely influence each other. As the need for sophisticated signal processing algorithms and hardware increase, their potential to make contributions to the communication revolution appears unbounded. Digital signal processing (DSP technology is widely used in numerous familiar products, peripherals of computers and the electronics world. This paper deals with the optimization of DSP environment for communication applications. Emphasis is given to the receiver part of the communication system; more specifically the channel separation aspect is discussed. No such algorithm for the computational saving for receiver part of communication system has been reported earlier. In this paper an attempt has been made to optimize the filtering operation.

  15. Novel sample preparation technique with needle-type micro-extraction device for volatile organic compounds in indoor air samples.

    Science.gov (United States)

    Ueta, Ikuo; Mizuguchi, Ayako; Fujimura, Koji; Kawakubo, Susumu; Saito, Yoshihiro

    2012-10-01

    A novel needle-type sample preparation device was developed for the effective preconcentration of volatile organic compounds (VOCs) in indoor air before gas chromatography-mass spectrometry (GC-MS) analysis. To develop a device for extracting a wide range of VOCs typically found in indoor air, several types of particulate sorbents were tested as the extraction medium in the needle-type extraction device. To determine the content of these VOCs, air samples were collected for 30min with the packed sorbent(s) in the extraction needle, and the extracted VOCs were thermally desorbed in a GC injection port by the direct insertion of the needle. A double-bed sorbent consisting of a needle packed with divinylbenzene and activated carbon particles exhibited excellent extraction and desorption performance and adequate extraction capacity for all the investigated VOCs. The results also clearly demonstrated that the proposed sample preparation method is a more rapid, simpler extraction/desorption technique than traditional sample preparation methods. PMID:22975183

  16. Effectiveness evaluation of sources of supply and systems filter in production process of breathing air

    Directory of Open Access Journals (Sweden)

    Woźniak Arkadiusz

    2015-12-01

    Full Text Available The determination of how efficiently filtration systems used for the production of breathing air used in hyperbaric environments are operating is significant both from theoretical and practical points of view. The quality of breathing air and the breathing mixes based on air is crucial with regard to divers' safety. Paradoxically, a change in regulations regarding quality requirements for breathing mixes has imposed the necessity to verify both the technical equipment and laboratory procedures used in their production and verification. The following material, which is a continuation of previous publications, presents results of the conducted research along with the evaluation of effectiveness of the filtration systems used by the Polish Navy.

  17. Contamination of the air and other environmental samples of the Ulm region by radioactive fission products after the accident of the Chernobyl reactor

    International Nuclear Information System (INIS)

    Since April 30, 1986, the radioactivity of the fission products released by the accident of the Chernobyl reactor has been measured in the air of the city of Ulm. The airborne dust samples were collected with flow calibrated samplers on cellulose acetate membrane filters and counted with a high resolution gamma ray spectrometer. Later on, the radioactivity measurements were expanded to other relevant environmental samples contaminated by radioactive atmospheric precipitates including grass, spruce needles, mosses, lichens, various kinds of food, drinking water, asphalt and concrete surface layers, municipal sewage sludge and sewage sludge ash. This paper reports the obtained results. (orig.)

  18. Development of a multicopter-carried whole air sampling apparatus and its applications in environmental studies.

    Science.gov (United States)

    Chang, Chih-Chung; Wang, Jia-Lin; Chang, Chih-Yuan; Liang, Mao-Chang; Lin, Ming-Ren

    2016-02-01

    To advance the capabilities of probing chemical composition aloft, we designed a lightweight remote-controlled whole air sampling component (WASC) and integrated it into a multicopter drone with agile maneuverability to perform aerial whole air sampling. A field mission hovering over an exhaust shaft of a roadway tunnel to collect air samples was performed to demonstrate the applicability of the multicopter-carried WASC apparatus. Ten aerial air samples surrounding the shaft vent were collected by the multicopter-carried WASC. Additional five samples were collected manually inside the shaft for comparison. These samples were then analyzed in the laboratory for the chemical composition of 109 volatile organic compounds (VOCs), CH4, CO, CO2, or CO2 isotopologues. Most of the VOCs in the upwind samples (the least affected by shaft exhaust) were low in concentrations (5.9 ppbv for total 109 VOCs), posting a strong contrast to those in the shaft exhaust (235.8 ppbv for total 109 VOCs). By comparing the aerial samples with the in-shaft samples for chemical compositions, the influence of the shaft exhaust on the surrounding natural air was estimated. Through the aerial measurements, three major advantages of the multicopter-carried WASC were demonstrated: 1. The highly maneuverable multicopter-carried WASC can be readily deployed for three-dimensional environmental studies at a local scale (0-1.5 km); 2. Aerial sampling with superior sample integrity and preservation conditions can now be performed with ease; and 3. Data with spatial resolution for a large array of gaseous species with high precision can be easily obtained. PMID:26386435

  19. A rapid method for the autoradiography of alpha active air sample filters

    International Nuclear Information System (INIS)

    The report describes an improved version of a technique using a phosphor screen and an optical photographic emulsion to detect alpha-active particles. The sensitivity of the technique when using 'instant' high speed polaroid film is reported. The equipment has been designed to produce rapid results and does not need 'darkroom' conditions. (author)

  20. External calibration strategy for trace element quantification in botanical samples by LA-ICP-MS using filter paper.

    Science.gov (United States)

    Nunes, Matheus A G; Voss, Mônica; Corazza, Gabriela; Flores, Erico M M; Dressler, Valderi L

    2016-01-28

    The use of reference solutions dispersed on filter paper discs is proposed for the first time as an external calibration strategy for matrix matching and determination of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, V and Zn in plants by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). The procedure is based on the use of filter paper discs as support for aqueous reference solutions, which are further evaporated, resulting in solid standards with concentrations up to 250 μg g(-1) of each element. The use of filter paper for calibration is proposed as matrix matched standards due to the similarities of this material with botanical samples, regarding to carbon concentration and its distribution through both matrices. These characteristics allowed the use of (13)C as internal standard (IS) during the analysis by LA-ICP-MS. In this way, parameters as analyte signal normalization with (13)C, carrier gas flow rate, laser energy, spot size, and calibration range were monitored. The calibration procedure using solution deposition on filter paper discs resulted in precision improvement when (13)C was used as IS. The method precision was calculated by the analysis of a certified reference material (CRM) of botanical matrix, considering the RSD obtained for 5 line scans and was lower than 20%. Accuracy of LA-ICP-MS determinations were evaluated by analysis of four CRM pellets of botanical composition, as well as by comparison with results obtained by ICP-MS using solution nebulization after microwave assisted digestion. Plant samples of unknown elemental composition were analyzed by the proposed LA method and good agreement were obtained with results of solution analysis. Limits of detection (LOD) established for LA-ICP-MS were obtained by the ablation of 10 lines on the filter paper disc containing 40 μL of 5% HNO3 (v v(-1)) as calibration blank. Values ranged from 0.05 to 0.81  μg g(-1). Overall, the use of filter paper as support for dried aqueous

  1. External calibration strategy for trace element quantification in botanical samples by LA-ICP-MS using filter paper.

    Science.gov (United States)

    Nunes, Matheus A G; Voss, Mônica; Corazza, Gabriela; Flores, Erico M M; Dressler, Valderi L

    2016-01-28

    The use of reference solutions dispersed on filter paper discs is proposed for the first time as an external calibration strategy for matrix matching and determination of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, V and Zn in plants by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). The procedure is based on the use of filter paper discs as support for aqueous reference solutions, which are further evaporated, resulting in solid standards with concentrations up to 250 μg g(-1) of each element. The use of filter paper for calibration is proposed as matrix matched standards due to the similarities of this material with botanical samples, regarding to carbon concentration and its distribution through both matrices. These characteristics allowed the use of (13)C as internal standard (IS) during the analysis by LA-ICP-MS. In this way, parameters as analyte signal normalization with (13)C, carrier gas flow rate, laser energy, spot size, and calibration range were monitored. The calibration procedure using solution deposition on filter paper discs resulted in precision improvement when (13)C was used as IS. The method precision was calculated by the analysis of a certified reference material (CRM) of botanical matrix, considering the RSD obtained for 5 line scans and was lower than 20%. Accuracy of LA-ICP-MS determinations were evaluated by analysis of four CRM pellets of botanical composition, as well as by comparison with results obtained by ICP-MS using solution nebulization after microwave assisted digestion. Plant samples of unknown elemental composition were analyzed by the proposed LA method and good agreement were obtained with results of solution analysis. Limits of detection (LOD) established for LA-ICP-MS were obtained by the ablation of 10 lines on the filter paper disc containing 40 μL of 5% HNO3 (v v(-1)) as calibration blank. Values ranged from 0.05 to 0.81  μg g(-1). Overall, the use of filter paper as support for dried aqueous

  2. Slip-Effect Functional Air Filter for Efficient Purification of PM2.5

    Science.gov (United States)

    Zhao, Xinglei; Wang, Shan; Yin, Xia; Yu, Jianyong; Ding, Bin

    2016-10-01

    Fabrication of air filtration materials (AFM) that allow air to easily flow through while retaining particles is a significant and urgent need due to the harmful airborne particulate matter pollution; however, this is still a challenging research area. Herein, we report novel slip-effect functional nanofibrous membranes with decreased air resistance (reduction rate of 40%) due to the slip flow of air molecules on the periphery of nanofibers. This was achieved through careful control over the diameters of electrospun polyacrylonitrile fibers and aperture size of fiber assembly. Fiber assembly with 86% of fiber diameters between 60–100 nm was found to be most effective for slip flow, as these diameters are close to the mean free path of air molecules (65.3 nm). Significantly, an equilibrium factor τ = df/d2 has been introduced to elucidate the effect of distance of adjacent fibers on the drag force of airflow. Furthermore, the most effective aperture size (>3.5 μm) for slip-effect has been determined. Ultimately, the new material displayed low air resistance of 29.5 Pa, high purification efficiency of 99.09%, good transmittance of 77%, and long service life. The successful fabrication of such materials can facilitate the development of high-performance AFMs for various applications.

  3. Assessing the impact of water filters and improved cook stoves on drinking water quality and household air pollution: a randomised controlled trial in Rwanda.

    Directory of Open Access Journals (Sweden)

    Ghislaine Rosa

    Full Text Available Diarrhoea and respiratory infections remain the biggest killers of children under 5 years in developing countries. We conducted a 5-month household randomised controlled trial among 566 households in rural Rwanda to assess uptake, compliance and impact on environmental exposures of a combined intervention delivering high-performance water filters and improved stoves for free. Compliance was measured monthly by self-report and spot-check observations. Semi-continuous 24-h PM2.5 monitoring of the cooking area was conducted in a random subsample of 121 households to assess household air pollution, while samples of drinking water from all households were collected monthly to assess the levels of thermotolerant coliforms. Adoption was generally high, with most householders reporting the filters as their primary source of drinking water and the intervention stoves as their primary cooking stove. However, some householders continued to drink untreated water and most continued to cook on traditional stoves. The intervention was associated with a 97.5% reduction in mean faecal indicator bacteria (Williams means 0.5 vs. 20.2 TTC/100 mL, p<0.001 and a median reduction of 48% of 24-h PM2.5 concentrations in the cooking area (p = 0.005. Further studies to increase compliance should be undertaken to better inform large-scale interventions.Clinicaltrials.gov; NCT01882777; http://clinicaltrials.gov/ct2/results?term=NCT01882777&Search=Search.

  4. In Vitro Exposures in Diesel Exhaust Atmospheres: Resuspension of PM from Filters Verses Direct Deposition of PM from Air

    Science.gov (United States)

    Lichtveld, Kim M.; Ebersviller, Seth M.; Sexton, Kenneth G.; Vizuete, William; Jaspers, Ilona; Jeffries, Harvey E.

    2012-01-01

    One of the most widely used in vitro particulate matter (PM) exposures methods is the collection of PM on filters, followed by resuspension in a liquid medium, with subsequent addition onto a cell culture. To avoid disruption of equilibria between gases and PM, we have developed a direct in vitro sampling and exposure method (DSEM) capable of PM-only exposures. We hypothesize that the separation of phases and post-treatment of filter-collected PM significantly modifies the toxicity of the PM compared to direct deposition, resulting in a distorted view of the potential PM health effects. Controlled test environments were created in a chamber that combined diesel exhaust with an urban-like mixture. The complex mixture was analyzed using both the DSEM and concurrently-collected filter samples. The DSEM showed that PM from test atmospheres produced significant inflammatory response, while the resuspension exposures at the same exposure concentration did not. Increasing the concentration of resuspended PM sixteen times was required to yield measurable IL-8 expression. Chemical analysis of the resuspended PM indicated a total absence of carbonyl compounds compared to the test atmosphere during the direct-exposures. Therefore, collection and resuspension of PM into liquid modifies its toxicity and likely leads to underestimating toxicity. PMID:22834915

  5. Determination of radiocarbon in stratospheric CO2, obtained through AirCore sampling.

    Science.gov (United States)

    Paul, Dipayan; Chen, Huilin; Been, Henk A.; Kivi, Rigel; Meijer, Harro A. J.

    2016-04-01

    The concentration of Greenhouse Gases (GHG), with carbon dioxide as the most prominent example, has been and still is increasing, predominantly due to emissions from fossil fuel combustion. CO2 is also the most important component of the global carbon cycle. Among other tracers, radiocarbon (Carbon-14) is a unique and an important atmospheric tracer used in the understanding of the global carbon cycle. Radiocarbon is a naturally occurring isotope (radioactive, t 1/2 = 5730 ± 40 years) of carbon produced through the interaction of thermalized neutrons and nitrogen in the upper atmosphere. Generally, for performing atmospheric radiocarbon measurements in the higher atmosphere, large samples (few liters of air) were collected using aircrafts and balloons. However, collecting stratospheric samples on a regular basis for radiocarbon analysis is extremely expensive. Here we describe the determination of radiocarbon concentrations in stratospheric CO2, collected using AirCore sampling. AirCore is an innovative sampling technique for obtaining vertical atmospheric profiles and, in Europe, is done on a regular basis at Sodankylä, Finland for CO2, CH4 and CO. The stratospheric parts of two such AirCore profiles were used in this study as a proof-of-principle. CO2 from the stratospheric air samples were extracted and converted to elemental carbon, which were then measured at the Accelerator Mass Spectrometric (AMS) facility of the Centre for Isotope Research (CIO) at the University of Groningen. The stratospheric part of the AirCore profile was divided into six sections, each contained approximately 10 μg C. A detailed description of the extraction, graphitization, AMS analysis and the derivation of the stratospheric radiocarbon profile will be the main focus. Through our results, we will show that AirCore is a viable sampling method for performing high-precision radiocarbon measurements of stratospheric CO2 with reasonably good spatial resolution on a regular basis

  6. Pesticide detection in air samples from contrasted houses and in their inhabitants' hair.

    Science.gov (United States)

    Raeppel, Caroline; Salquèbre, Guillaume; Millet, Maurice; Appenzeller, Brice M R

    2016-02-15

    In order to identify associations between indoor air contamination and human exposure to pesticides, hair samples from 14 persons (9 adults and 5 children below 12 years) were collected simultaneously with the air of their 5 contrasted houses. Three houses were situated in Alsace (France), one in Lorraine (France) and one in Luxembourg (Luxembourg). Houses were located in urban (n=3), semi-urban (n=1) and rural areas (n=1). Twenty five (25) pesticides were detected at least once in indoor air samples and 20 pesticides were detected at least once in hair samples. The comparison between hair and air samples for the same sampling periods shows that pesticides detected in the two matrices were not necessarily associated. Exposure profiles varied from one home to another but also between inhabitants of the same home, suggesting that exposure can be different between inhabitants of the same home. This study demonstrated the usefulness and the complementarity of hair analysis, for the personalized biomonitoring of people exposure to pesticides, and air analysis, for the identification of airborne exposure and house contamination. PMID:26706757

  7. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Science.gov (United States)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  8. Air sampling for hepatitis B surface antigen in a dental operatory.

    Science.gov (United States)

    Petersen, N J; Bond, W W; Favero, M S

    1979-09-01

    Forty samples of air with a mean sample volume of 104 liters were collected during the treatment of patients whose blood was positive for HBsAG: no samples contained HBsAG and occult blood. These findings suggest that, if environmentally mediated transmission of hepatitis B occurs in the dental operatory, it is more likely to occur through contact with contaminated surfaces than through the airborne route.

  9. Ammonia and ammonium over the southern Baltic Sea. Part 1. Preparation of aerosol and air samples for the determination of ammonia by the indophenol method

    Directory of Open Access Journals (Sweden)

    Lucyna Falkowska

    2004-06-01

    Full Text Available 1997 saw the start of a study into the spatial and temporal changes in the chemical composition of the atmosphere over the littoral and offshore waters of the Baltic Sea. Collection of samples and their subsequent chemical analysis was preceded by meticulous laboratory experiments concerning the validation and adaptation of the analytical procedures. The colorimetric indophenol blue technique was used to analyse the aerosol samples for the concentration of ammonium ions and the air samples for their gaseous ammonia. The samples were collected with PTFE-filters and Whatman 41 filters coated with 5% orthophosphoric acid. This acid enhances the aerosol sampling efficacy but reduces the pH of the reaction in which indophenol is formed. The pH of the aerosol samples thus had to be raised, and this in turn required an alteration to the original procedure prior to ammonia determination. It was demonstrated that the addition of 0.1 N KOH to the filters coated with H3PO4 increases the pH of the reaction medium to the required level of pH = 8-11.5 and does not substantially influence the precision of the determination; the error of the modified procedure was of the order of 5.2%.      Air samples for the determination of gaseous ammonia were collected with annular denuders. Oxalic acid and citric acid are the usual impregnating agents. In the present experiments oxalic acid was used for denuder impregnation; it turned out to be more effective than citric acid under the conditions of the southern Baltic Sea.      The detection limit of the indophenol blue method in these laboratory experiments was 0.045 mmol dm-3. The respective relative standard deviations (RSD within the range of higher and lower concentrations were 0.64% and 4.53%.

  10. Removal of Gross Air Embolization from Cardiopulmonary Bypass Circuits with Integrated Arterial Line Filters: A Comparison of Circuit Designs.

    Science.gov (United States)

    Reagor, James A; Holt, David W

    2016-03-01

    Advances in technology, the desire to minimize blood product transfusions, and concerns relating to inflammatory mediators have lead many practitioners and manufacturers to minimize cardiopulmonary bypass (CBP) circuit designs. The oxygenator and arterial line filter (ALF) have been integrated into one device as a method of attaining a reduction in prime volume and surface area. The instructions for use of a currently available oxygenator with integrated ALF recommends incorporating a recirculation line distal to the oxygenator. However, according to an unscientific survey, 70% of respondents utilize CPB circuits incorporating integrated ALFs without a path of recirculation distal to the oxygenator outlet. Considering this circuit design, the ability to quickly remove a gross air bolus in the blood path distal to the oxygenator may be compromised. This in vitro study was designed to determine if the time required to remove a gross air bolus from a CPB circuit without a path of recirculation distal to the oxygenator will be significantly longer than that of a circuit with a path of recirculation distal to the oxygenator. A significant difference was found in the mean time required to remove a gross air bolus between the circuit designs (p = .0003). Additionally, There was found to be a statistically significant difference in the mean time required to remove a gross air bolus between Trial 1 and Trials 4 (p = .015) and 5 (p =.014) irrespective of the circuit design. Under the parameters of this study, a recirculation line distal to an oxygenator with an integrated ALF significantly decreases the time it takes to remove an air bolus from the CPB circuit and may be safer for clinical use than the same circuit without a recirculation line.

  11. Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

    International Nuclear Information System (INIS)

    conventional liquid measurements, and by analyzing IAEA-153 reference material (Trace Elements in Milk Powder); a good agreement with the certified value for phosphorus was obtained. - Highlights: • Sample preparation via deposition of liquids on pre-cut filter disks. • Sample introduction via laser ablation of dried filters. • Representative sampling avoids bias. • Signal quantification via external calibration and aqueous standard solutions. • Alternative approach for quantifying P in challenging matrix

  12. Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

    Energy Technology Data Exchange (ETDEWEB)

    Nischkauer, Winfried [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna (Austria); Department of Analytical Chemistry, Ghent University, Ghent (Belgium); Vanhaecke, Frank [Department of Analytical Chemistry, Ghent University, Ghent (Belgium); Bernacchi, Sébastien; Herwig, Christoph [Institute of Chemical Engineering, Vienna University of Technology, Vienna (Austria); Limbeck, Andreas, E-mail: Andreas.Limbeck@tuwien.ac.at [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna (Austria)

    2014-11-01

    conventional liquid measurements, and by analyzing IAEA-153 reference material (Trace Elements in Milk Powder); a good agreement with the certified value for phosphorus was obtained. - Highlights: • Sample preparation via deposition of liquids on pre-cut filter disks. • Sample introduction via laser ablation of dried filters. • Representative sampling avoids bias. • Signal quantification via external calibration and aqueous standard solutions. • Alternative approach for quantifying P in challenging matrix.

  13. 容积式空压机用空气滤清器技术水平现状综述%Overview of Current Technical Level of Air Filter for Displacement Air Compressor

    Institute of Scientific and Technical Information of China (English)

    谭强

    2012-01-01

    评述空压机用空气滤清器的作用,对压缩机机组能效水平\\辅助部件的性能和寿命的影响;对比国内空气压缩机产品技术标准中对空气滤清器的性能和技术要求;概述当前空气滤清器主导产品的使用现状,以及空气滤清器产品标准和试验标准的现状;列出压缩机用空气滤清器要求进行规范化管理的技术条款.期望建立健全压缩机行业空气滤清器产品的技术标准和验收准则,满足压缩机制造厂和最终用户的要求.%This paper reviews the function of air filter for air compressor,the effect on compressor unit energy efficiency level,and the effect on performance and service life of auxiliary parts of the compressor, and contrasts the performance and technical requirements of air filter in domestic air compressor product technical standards and summarizes the current application situation of leading air filter products and the present situation of air filter product standards and test standards.This paper lists the technical items for standardized management of compressor air filter.It is expected to establish and perfect the air filter product technical standards and acceptance criteria of the compressor industry,to meet the compressor manufacturers and end-users requirements.

  14. Determination of metals in air samples using X-Ray fluorescence associated the APDC preconcentration technique

    Energy Technology Data Exchange (ETDEWEB)

    Nardes, Raysa C.; Santos, Ramon S.; Sanches, Francis A.C.R.A.; Gama Filho, Hamilton S.; Oliveira, Davi F.; Anjos, Marcelino J., E-mail: rc.nardes@gmail.com, E-mail: ramonziosp@yahoo.com.br, E-mail: francissanches@gmail.com, E-mail: hamiltongamafilho@hotmail.com, E-mail: davi.oliveira@uerj.br, E-mail: marcelin@uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Instituto de Fisica. Departamento de Fisica Aplicada e Termodinamica

    2015-07-01

    Air pollution has become one of the leading quality degradation factors of life for people in large urban centers. Studies indicate that the suspended particulate matter in the atmosphere is directly associated with risks to public health, in addition, it can cause damage to fauna, flora and public / cultural patrimonies. The inhalable particulate materials can cause the emergence and / or worsening of chronic diseases related to respiratory system and other diseases, such as reduced physical strength. In this study, we propose a new method to measure the concentration of total suspended particulate matter (TSP) in the air using an impinger as an air cleaning apparatus, preconcentration with APDC and Total Reflection X-ray Fluorescence technique (TXRF) to analyze the heavy metals present in the air. The samples were collected from five random points in the city of Rio de Janeiro/Brazil. Analyses of TXRF were performed at the Brazilian Synchrotron Light Laboratory (LNLS). The technique proved viable because it was able to detect five important metallic elements to environmental studies: Cr, Fe, Ni, Cu and Zn. This technique presented substantial efficiency in determining the elementary concentration of air pollutants, in addition to low cost. It can be concluded that the metals analysis technique in air samples using an impinger as sample collection instrument associated with a complexing agent (APDC) was viable because it is a low-cost technique, moreover, it was possible the detection of five important metal elements in environmental studies associated with industrial emissions and urban traffic. (author)

  15. Determination of metals in air samples using X-Ray fluorescence associated the APDC preconcentration technique

    International Nuclear Information System (INIS)

    Air pollution has become one of the leading quality degradation factors of life for people in large urban centers. Studies indicate that the suspended particulate matter in the atmosphere is directly associated with risks to public health, in addition, it can cause damage to fauna, flora and public / cultural patrimonies. The inhalable particulate materials can cause the emergence and / or worsening of chronic diseases related to respiratory system and other diseases, such as reduced physical strength. In this study, we propose a new method to measure the concentration of total suspended particulate matter (TSP) in the air using an impinger as an air cleaning apparatus, preconcentration with APDC and Total Reflection X-ray Fluorescence technique (TXRF) to analyze the heavy metals present in the air. The samples were collected from five random points in the city of Rio de Janeiro/Brazil. Analyses of TXRF were performed at the Brazilian Synchrotron Light Laboratory (LNLS). The technique proved viable because it was able to detect five important metallic elements to environmental studies: Cr, Fe, Ni, Cu and Zn. This technique presented substantial efficiency in determining the elementary concentration of air pollutants, in addition to low cost. It can be concluded that the metals analysis technique in air samples using an impinger as sample collection instrument associated with a complexing agent (APDC) was viable because it is a low-cost technique, moreover, it was possible the detection of five important metal elements in environmental studies associated with industrial emissions and urban traffic. (author)

  16. Correlation of levels of volatile versus carcinogenic particulate polycyclic aromatic hydrocarbons in air samples from smokehouses

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Christensen, J M

    1991-01-01

    In the present study, data on the concentration of polycyclic aromatic hydrocarbons (PAH) in air samples from fish smokehouses (Nordholm et al. 1986) and meat smokehouses (Hansen et al. submitted for publication) were used to analyze the extent to which six different volatile PAH compounds could...... carcinogenic PAH compounds in air samples from smokehouses, whereas fluoranthene and pyrene displayed the highest specificity. However, when the applicability of the six markers was tested on air samples from iron foundries, only naphthalene and pyrene were useful as markers for the carcinogenic compounds...... function as markers for the total concentration of six different carcinogenic particulate PAH compounds. Although a significant positive correlation was observed between the concentration of each of six volatile compounds and the total concentration of carcinogenic PAH compounds, a particularly good...

  17. Effectiveness of heating, ventilation and air conditioning system with HEPA filter unit on indoor air quality and asthmatic children's health

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ying; Raja, Suresh; Ferro, Andrea R.; Jaques, Peter A.; Hopke, Philip K. [Clarkson University, 8 Clarkson Avenue, Center for Air Resources Engineering and Science, Potsdam, NY 13699 (United States); Gressani, Cheryl; Wetzel, Larry E. [Air Innovations, Inc, 7000 Performance Drive, North Syracuse, NY 13212 (United States)

    2010-02-15

    Poor indoor air quality has been linked to the exacerbation of asthma symptoms in children. Because people spend most of their time indoors, improving indoor air quality may provide some relief to asthma sufferers. A study was conducted to assess whether operating an air cleaning/ventilating unit (HEPAiRx {sup registered}) in a child's bedroom can improve his/her respiratory health. Thirty children diagnosed with asthma were randomly split into two groups. For the first six weeks, group A had the air cleaning/ventilating unit (HEPAiRx {sup registered}) running in the bedrooms of the participants and group B did not; for the second six weeks, both groups had the cleaners running in the bedrooms; and, for the final six weeks, group A turned the cleaners off and group B kept theirs running. Indoor air quality parameters, including temperature, relative humidity, particulate matter (PM 0.5-10 {mu}m), carbon monoxide, carbon dioxide and total volatile organic compound (TVOC) concentrations, were monitored in each bedroom using an AirAdvice indoor air quality multi-meter. As a measure of pulmonary inflammation, exhaled breath condensate (EBC) was collected every sixth day and analyzed for nitrate and pH. Peak expiratory flow (PEF) was also measured. PM and TVOC concentrations decreased with operation of the HEPAiRx an average of 72% and 59%, respectively. The EBC nitrate concentrations decreased significantly and the EBC pH and PEF values increased significantly with operation of the unit (p < 0.001 when comparing on/off sample means). These results indicate that air cleaning in combination with ventilation can effectively reduce symptoms for asthma sufferers. (author)

  18. Odour and ammonia removal from pig house exhaust air using a biotrickling filter

    NARCIS (Netherlands)

    Melse, R.W.; Mol, G.

    2004-01-01

    Odour from agricultural activities, such as the spreading of manure and the housing of animals, is increasingly being considered a nuisance in densely populated countries like the Netherlands. The objective of this research was to study the odour removal from pig house exhaust air by a biotrickling

  19. The role of loading rate, backwashing, water and air velocities in an up-flow nitrifying tertiary filter.

    Science.gov (United States)

    Vigne, Emmanuelle; Choubert, Jean-Marc; Canler, Jean-Pierre; Heduit, Alain; Sørensen, Kim Helleshøj; Lessard, Paul

    2011-01-01

    The vertical distribution of nitrification performances in an up-flow biological aerated filter operated at tertiary nitrification stage is evaluated in this paper. Experimental data were collected from a semi-industrial pilot-plant under various operating conditions. The actual and the maximum nitrification rates were measured at different levels inside the up-flow biofilter. A nitrogen loading rate higher than 1.0 kg NH4-Nm(-3)_mediad(-1) is necessary to obtain nitrification activity over all the height of the biofilter. The increase in water and air velocities from 6 to 10 m h(-1) and 10 to 20 m h(-1) has increased the nitrification rate by 80% and 20% respectively. Backwashing decreases the maximum nitrification rate in the media by only 3-14%. The nitrification rate measured at a level of 0.5 m above the bottom of the filter is four times higher than the applied daily average volumetric nitrogen loading rate up to 1.5 kg NH4-N m(-3)_mediad(-1). Finally, it is shown that 58% of the available nitrification activity is mobilized in steady-state conditions while up to 100% is used under inflow-rate increase.

  20. Air-sampling inlet contamination by aircraft emissions on the NASA CV-990 aircraft

    Science.gov (United States)

    Condon, E. P.; Vedder, J. F.

    1984-01-01

    Results of an experimental investigation of the contamination of air sampling inlets by aircraft emissions from the NASA CV-990 research aircraft are presented. This four-engine jet aircraft is a NASA facility used for many different atmospheric and meteorological experiments, as well as for developing spacecraft instrumentation for remote measurements. Our investigations were performed to provide information on which to base the selection of sampling locations for a series of multi-instrument missions for measuring tropospheric trace gases. The major source of contamination is the exhaust from the jet engines, which generate many of the same gases that are of interest in atmospheric chemistry, as well as other gases that may interfere with sampling measurements. The engine exhaust contains these gases in mixing ratios many orders of magnitude greater than those that occur in the clean atmosphere which the missions seek to quantify. Pressurized samples of air were collected simultaneously from a scoop located forward of the engines to represent clean air and from other multiport scoops at various aft positions on the aircraft. The air samples were analyzed in the laboratory by gas chromatography for carbon monoxide, an abundant combustion by-product. Data are presented for various scoop locations under various flight conditions.

  1. Tea bag filter paper as a novel protective membrane for micro-solid phase extraction of butachlor in aqueous samples.

    Science.gov (United States)

    Pelden, Tshering; Thammaknet, Chongdee; Thavarungkul, Panote; Kanatharana, Proespichaya

    2014-01-01

    An innovative, cost-effective, simple, and environmental friendly tea bag filter paper protected micro-solid phase extraction (μ-SPE) technique was developed for the first time with the aim to miniaturize and minimize the use of organic solvents for the extraction and determination of butachlor in aqueous samples. The μ-SPE device was produced by packing 3.0 mg of an easily synthesized new sorbent, hydroxyl-functionalized polypyrrole (OH-PPY), inside a small tea bag filter paper sachet (1.0 cm × 0.5 cm) that served as a protective envelope. Both the extraction and desorption procedures were facilitated by sonication. Due to the high porosity and the fast water absorption of the tea bag filter paper, the analyte could easily diffuse through and enhance the interaction with the sorbent. Under the optimized conditions for the GC-ECD and the μ-SPE, the limit of detection (S/N ≥ 3) was 2.0 μg L(-1) while the limit of quantitation (S/N ≥ 10) was 10.0 μg L(-1). The recoveries of the butachlor spiked at 0.050, 0.10, and 0.50 μg mL(-1) ranged from 77.9 ± 3.0 to 112.5 ± 2.9%. The proposed method was successfully applied for the determination of butachlor in water samples from paddy cultivation sites. The levels found were from non-detectable to 24.71 ± 0.37 μg L(-1).

  2. Study of Mass Oxygen Transfer in a Biotrickling Filter for Air Pollution Control

    OpenAIRE

    San-Valero, Pau; Gabaldón García, Carmen; Peñarrocha Oltra, Josep Manuel; Pérez Gil, María del Carmen

    2012-01-01

    Biotrickling filtration is a potential and cost effective alternative for the treatment of volatile organic compound (VOC) emissions in air, so it is necessary to deepen into the key aspects of design and operation for the optimization of this technology. One of these factors is the oxygen mass transfer of the process. This study would facilitate the selection of the packing material and the mathematical modelling and simulation of bioreactors. Four plastic packing materials with ...

  3. Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis

    International Nuclear Information System (INIS)

    This document describes the results of the data quality objective (DQO) process undertaken to define data needs for state and federal requirements associated with toxic, hazardous, and/or radiological air emissions under the jurisdiction of the River Protection Project (RPP). Hereafter, this document is referred to as the Air DQO. The primary drivers for characterization under this DQO are the regulatory requirements pursuant to Washington State regulations, that may require sampling and analysis. The federal regulations concerning air emissions are incorporated into the Washington State regulations. Data needs exist for nonradioactive and radioactive waste constituents and characteristics as identified through the DQO process described in this document. The purpose is to identify current data needs for complying with regulatory drivers for the measurement of air emissions from RPP facilities in support of air permitting. These drivers include best management practices; similar analyses may have more than one regulatory driver. This document should not be used for determining overall compliance with regulations because the regulations are in constant change, and this document may not reflect the latest regulatory requirements. Regulatory requirements are also expected to change as various permits are issued. Data needs require samples for both radionuclides and nonradionuclide analytes of air emissions from tanks and stored waste containers. The collection of data is to support environmental permitting and compliance, not for health and safety issues

  4. Passive air sampling of PCBs, PBDEs, and organochlorine pesticides across Europe.

    Science.gov (United States)

    Jaward, Foday M; Farrar, Nick J; Harner, Tom; Sweetman, Andrew J; Jones, Kevin C

    2004-01-01

    This study presents concurrently sampled ambient air data for a range of persistent organic pollutants at the continental scale. This was achieved using a passive air sampling system, deploying polyurethane foam disks, which was prepared in one laboratory, sealed to prevent contamination, sent out by courier to volunteers participating in different countries, exposed for 6 weeks, collected, resealed, and returned to the laboratory for analysis. Europe was the study area--a region with a history of extensive POPs usage and emission and with marked national differences in population density, the degree of urbanization and industrial/agricultural development. Samplers were deployed at remote/rural/urban locations in 22 countries and analyzed for PCBs, a range of organochlorine pesticides (HCB, alpha-HCH, gamma-HCH, ppDDT, ppDDE), and PBDEs. Calculated air concentrations were in line with those obtained by conventional active air sampling techniques. The geographical pattern of all compounds reflected suspected regional emission patterns and highlighted localized hotspots. PCB and PBDE levels varied by over 2 orders of magnitude; the highest values were detected in areas of high usage and were linked to urbanized areas. HCB was relatively uniformly distributed, reflecting its persistence and high degree of mixing in air. Higher gamma-HCH, ppDDT, and ppDDE levels generally occurred in South and East Europe. PMID:14740714

  5. Distribution of small dispersive coal dust particles and absorbed radioactive chemical elements in conditions of forced acoustic resonance in iodine air filter at nuclear power plant

    CERN Document Server

    Ledenyov, Oleg P

    2013-01-01

    The physical features of distribution of the small dispersive coal dust particles and the adsorbed radioactive chemical elements and their isotopes in the absorber with the granular filtering medium with the cylindrical coal granules were researched in the case of the intensive air dust aerosol stream flow through the iodine air filter (IAF). It was shown that, at the certain aerodynamic conditions in the IAF, the generation of the acoustic oscillations is possible. It was found that the acoustic oscillations generation results in an appearance of the standing acoustic waves of the air pressure (density) in the IAF. In the case of the intensive blow of the air dust aerosol, it was demonstrated that the standing acoustic waves have some strong influences on both: 1) the dynamics of small dispersive coal dust particles movement and their accumulation in the IAF; 2) the oversaturation of the cylindrical coal granules by the adsorbed radioactive chemical elements and their isotopes in the regions, where the antin...

  6. THE STUDY OF BACTERIAL POPULATION IN AIR SAMPLES OF A TERTIARY CARE HOSPITAL

    Directory of Open Access Journals (Sweden)

    Partha Sarathi

    2014-06-01

    Full Text Available CONTEXT: The bacterial load in different air samples from environment of most hospitals remained undetermined. Any direct correlation between such bacterial load and the nosocomial infection are also lacking. Only higher bacterial load in air of a particular hospital environment may indicate higher risk of airborne cross infections. AIMS: The study is to determine the bacterial presence per unit volume of air, and the factors influencing the bioload. SETTINGS AND DESIGN: The air samples were collected from different locations of our tertiary care hospital, during Jul 2011 to June 2012 with information like room space per patient, number of daily average visitors, system of air circulation and house-keeping quality. METHODS: A specific volume of air was impacted on a plastic strips containing nutrient agar by air sampler La200, Hi-Media. Following incubation for 24 hour bacterial colonies were counted and organisms were identified up to genus level. RESULTS: Mostly Gram positive cocci followed by Gram positive and a few Gram negative bacilli were detected. The highest bacterial load was found in general outdoor premises (2456 CFU/cm, followed by some extremely crowded general wards (573 CFU/cm. The lowest count of such was found in nursery area (94 CFU/cm, where special emphasis was given on cleanliness, room ventilation and visitor’s restriction. Similarly variations in bacterial loads were also noted in different times in a day and in different seasons in a year. The bioload in all tested samples were within permissible limits. CONCLUSIONS: By appropriate measures the aerobic bacterial load in hospital environment can be restricted within optimal level

  7. Development and calibration of real-time PCR for quantification of airborne microorganisms in air samples

    Science.gov (United States)

    An, Hey Reoun; Mainelis, Gediminas; White, Lori

    This manuscript describes the coupling of bioaerosol collection and the use of real-time PCR (RT-PCR) to quantify the airborne bacteria. The quantity of collected bacteria determined by RT-PCR is compared with conventional quantification techniques, such as culturing, microscopy and airborne microorganism counting by using optical particle counter (OPC). Our data show that an experimental approach used to develop standard curves for use with RT-PCR is critical for accurate sample quantification. Using universal primers we generated 12 different standard curves which were used to quantify model organism Escherichia coli (Migula) Catellani from air samples. Standard curves prepared using a traditional approach, where serially diluted genomic DNA extracted from pure cultured bacteria were used in PCR reaction as a template DNA yielded significant underestimation of sample quantities compared to airborne microorganism concentration as measured by an OPC. The underestimation was especially pronounced when standard curves were built using colony forming units (CFUs). In contrast, the estimate of cell concentration in an air sample by RT-PCR was more accurate (˜60% compared to the airborne microorganism concentration) when the standard curve was built using aerosolized E. coli. The accuracy improved even further (˜100%) when air samples used to build the standard curves were diluted first, then the DNA extracted from each dilution was amplified by the RT-PCR—to mimic the handling of air samples with unknown and possibly low concentration. Therefore, our data show that standard curves used for quantification by RT-PCR needs to be prepared using the same environmental matrix and procedures as handling of the environmental sample in question. Reliance on the standard curves generated with cultured bacterial suspension (a traditional approach) may lead to substantial underestimation of microorganism quantities in environmental samples.

  8. Development of a wireless air pollution sensor package for aerial-sampling of emissions

    Science.gov (United States)

    A new sensor system for mobile and aerial emission sampling was developed for open area pollutant sources, such as prescribed forest burns. The sensor system, termed “Kolibri”, consists of multiple low-cost air quality sensors measuring CO2, CO, samplers for particulate matter wi...

  9. Extreme 13C depletion of CCl2F2 in firn air samples from NEEM, Greenland

    NARCIS (Netherlands)

    Zuiderweg, A.T.; Holzinger, R.; Röckmann, T.

    2012-01-01

    A series of 12 high volume air samples collected from the S2 firn core during the North Greenland Eemian Ice Drilling (NEEM) 2009 campaign have been measured for mixing ratio and stable carbon isotope composition of the chlorofluorocarbon CFC- 12 (CCl2F2). While the mixing ratio measurements compare

  10. the nature of air flow near the inlets of blunt dust sampling probes

    Science.gov (United States)

    Vincent, J. H.; Hutson, D.; Mark, D.

    This paper sets out to describe the nature of air flow near blunt dust samplers in a way which allows a relatively simple assessment of their performances for collecting dust particles. Of particular importance is the shape of the limiting stream surface which divides the sampled air from that which passes outside the sampler, and how this is affected by the free-stream air velocity, the sampling flow rate, and the shape of the sampler body. This was investigated for two-dimensional and axially-symmetric sampler systems by means of complementary experiments using electrolytic tank potential flow analogues and a wind tunnel respectively. For extreme conditions the flow of air entering the sampling orifice may be wholly divergent or wholly convergent. For a wide range of intermediate conditions, however, the flow first diverges then converges, exhibiting a so-called "spring onion effect". Whichever of these applies for a particular situation, the flow may be considered to consist of two parts, the outer one dominated by the flow about the sampler body and the inner one dominated by the flow into the sampling orifice. Particle transport in this two-part flow may be assessed using ideas borrowed from thin-walled probe theory.

  11. Conceptual Design of Portable Filtered Air Suction Systems For Prevention of Released Radioactive Gas under Severe Accidents of NPP

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Beom W.; Choi, Su Y.; Yim, Man S.; Rim, Chun T. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    It becomes evident that severe accidents may occur by unexpected disasters such as tsunami, heavy flood, or terror. Once radioactive material is released from NPP through severe accidents, there are no ways to prevent the released radioactive gas spreading in the air. As a remedy for this problem, the idea on the portable filtered air suction system (PoFASS) for the prevention of released radioactive gas under severe accidents was proposed. In this paper, the conceptual design of a PoFASS focusing on the number of robot fingers and robot arm rods are proposed. In order to design a flexible robot suction nozzle, mathematical models for the gaps which represent the lifted heights of extensible covers for given convex shapes of pipes and for the covered areas are developed. In addition, the system requirements for the design of the robot arms of PoFASS are proposed, which determine the accessible range of leakage points of released radioactive gas. In this paper, the conceptual designs of the flexible robot suction nozzle and robot arm have been conducted. As a result, the minimum number of robot fingers and robot arm rods are defined to be four and three, respectively. For further works, extensible cover designs on the flexible robot suction nozzle and the application of the PoFASS to the inside of NPP should be studied because the radioactive gas may be released from connection pipes between the containment building and auxiliary buildings.

  12. Miniaturized dielectric waveguide filters

    Science.gov (United States)

    Sandhu, Muhammad Y.; Hunter, Ian C.

    2016-10-01

    Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.

  13. Evaluation of a dry filter and an electrostatic precipitator for exhaust air cleaning at commercial non-cage laying hen houses

    NARCIS (Netherlands)

    Winkel, A.; Mosquera Losada, J.; Aarnink, A.J.A.; Groot Koerkamp, P.W.G.; Ogink, N.W.M.

    2015-01-01

    The removal performance of two exhaust air cleaning systems for abatement of particulate matter (PM) emission in poultry houses were investigated: a commercially available dry filter (DF) and a full-scale prototype electrostatic precipitator (ESP). Each system was connected to two commercial, non-ca

  14. Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis

    International Nuclear Information System (INIS)

    This document describes the results of the data quality objective (DQO) process undertaken to define data needs for state and federal requirements associated with toxic, hazardous, and/or radiological air emissions under the jurisdiction of the River Protection Project (RPP). Hereafter, this document is referred to as the Air DQO. The primary drivers for characterization under this DQO are the regulatory requirements pursuant to Washington State regulations, that may require sampling and analysis. The federal regulations concerning air emissions are incorporated into the Washington State regulations. Data needs exist for nonradioactive and radioactive waste constituents and characteristics as identified through the DQO process described in this document. The purpose is to identify current data needs for complying with regulatory drivers for the measurement of air emissions from RPP facilities in support of air permitting. These drivers include best management practices; similar analyses may have more than one regulatory driver. This document should not be used for determining overall compliance with regulations because the regulations are in constant change, and this document may not reflect the latest regulatory requirements. Regulatory requirements are also expected to change as various permits are issued. Data needs require samples for both radionuclides and nonradionuclide analytes of air emissions from tanks and stored waste containers. The collection of data is to support environmental permitting and compliance, not for health and safety issues. This document does not address health or safety regulations or requirements (those of the Occupational Safety and Health Administration or the National Institute of Occupational Safety and Health) or continuous emission monitoring systems. This DQO is applicable to all equipment, facilities, and operations under the jurisdiction of RPP that emit or have the potential to emit regulated air pollutants

  15. Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    MULKEY, C.H.

    1999-07-06

    This document describes the results of the data quality objective (DQO) process undertaken to define data needs for state and federal requirements associated with toxic, hazardous, and/or radiological air emissions under the jurisdiction of the River Protection Project (RPP). Hereafter, this document is referred to as the Air DQO. The primary drivers for characterization under this DQO are the regulatory requirements pursuant to Washington State regulations, that may require sampling and analysis. The federal regulations concerning air emissions are incorporated into the Washington State regulations. Data needs exist for nonradioactive and radioactive waste constituents and characteristics as identified through the DQO process described in this document. The purpose is to identify current data needs for complying with regulatory drivers for the measurement of air emissions from RPP facilities in support of air permitting. These drivers include best management practices; similar analyses may have more than one regulatory driver. This document should not be used for determining overall compliance with regulations because the regulations are in constant change, and this document may not reflect the latest regulatory requirements. Regulatory requirements are also expected to change as various permits are issued. Data needs require samples for both radionuclides and nonradionuclide analytes of air emissions from tanks and stored waste containers. The collection of data is to support environmental permitting and compliance, not for health and safety issues. This document does not address health or safety regulations or requirements (those of the Occupational Safety and Health Administration or the National Institute of Occupational Safety and Health) or continuous emission monitoring systems. This DQO is applicable to all equipment, facilities, and operations under the jurisdiction of RPP that emit or have the potential to emit regulated air pollutants.

  16. Estimating occupancy and abundance of stream amphibians using environmental DNA from filtered water samples

    Science.gov (United States)

    Pilliod, David S.; Goldberg, Caren S.; Arkle, Robert S.; Waits, Lisette P.

    2013-01-01

    Environmental DNA (eDNA) methods for detecting aquatic species are advancing rapidly, but with little evaluation of field protocols or precision of resulting estimates. We compared sampling results from traditional field methods with eDNA methods for two amphibians in 13 streams in central Idaho, USA. We also evaluated three water collection protocols and the influence of sampling location, time of day, and distance from animals on eDNA concentration in the water. We found no difference in detection or amount of eDNA among water collection protocols. eDNA methods had slightly higher detection rates than traditional field methods, particularly when species occurred at low densities. eDNA concentration was positively related to field-measured density, biomass, and proportion of transects occupied. Precision of eDNA-based abundance estimates increased with the amount of eDNA in the water and the number of replicate subsamples collected. eDNA concentration did not vary significantly with sample location in the stream, time of day, or distance downstream from animals. Our results further advance the implementation of eDNA methods for monitoring aquatic vertebrates in stream habitats.

  17. Development of Air Filter in Dusty Surroundings%多尘环境使用的空气滤清器的研发

    Institute of Scientific and Technical Information of China (English)

    李继红

    2011-01-01

    在盆式精滤器和旋流管粗滤器的基础上开发了XC-Ⅰ系统粗滤器。试验证明,该粗滤器具有过滤效率高,进气阻力低,粗滤自动排尘,结构简单,安装方便,成本低的优点。%Based on bowl shaped and swirl tube air filters,XC-Ⅰ series pre-filters are developed.The test results show the filter has advantages of high filtering efficiency,low intake resistance,automatic dusting,simple structure,convenient installation and low costing.

  18. Diffusive sampling and measurement of microbial volatile organic compounds in indoor air.

    Science.gov (United States)

    Araki, A; Eitaki, Y; Kawai, T; Kanazawa, A; Takeda, M; Kishi, R

    2009-10-01

    Microbial volatile organic compounds (MVOC), chemicals emitted from various microorganisms, in indoor air have been of concern in recent years. For large field studies, diffusive samplers are widely used to measure indoor environments. Since the sampling rate of a sampler is a fundamental parameter to calculate concentration, the sampling rates of eight MVOC with diffusive samplers were determined experimentally using a newly developed water-bubbling method: air was supplied to the MVOC-solutions and the vapor collected in an exposure bag, where diffusive and active samplers were placed in parallel for comparison. Correlations between the diffusive and active samplings gave good linear regressions. The sampling rates were 30-35 ml/min and the detection limits were 0.044-0.178 microg/m(3), as determined by GC/MS analysis. Application of the sampling rates in indoor air was validated by parallel sampling of the diffusive and active sampling method. 5% Propan-2-ol/CS(2) was the best solvent to desorb the compounds from absorbents. The procedure was applied to a field study in 41 dwellings. The most frequently detected compounds were hexan-2-one and heptan-2-one, with 97.5% detection rates and geometric mean values of 0.470 and 0.302 microg/m(3), respectively. This study shows that diffusive samplers are applicable to measure indoor MVOC levels. Practical Implications At present, there are still limited reports on indoor Microbial Volatile Organic Compounds (MVOC) levels in general dwellings and occupants' health. Compared with active sampling methods, air sampling using a diffusive sampler is particularly advantageous for use in large field studies due to its smallness, light-size, easy-handling, and cost-effectiveness. In this study, sampling rates of selected MVOC of the diffusive sampler were determined using the water-bubbling method: generating gases by water-bubbling and exposing the diffusive and active samplers at the same time. The obtained sampling rates

  19. Image-domain sampling properties of the Hotelling Observer in CT using filtered back-projection

    Science.gov (United States)

    Sanchez, Adrian A.; Sidky, Emil Y.; Pan, Xiaochuan

    2015-03-01

    The Hotelling Observer (HO),1 along with its channelized variants,2 has been proposed for image quality evaluation in x-ray CT.3,4 In this work, we investigate HO performance for a detection task in parallel-beam FBP as a function of two image-domain sampling parameters, namely pixel size and field-of-view. These two parameters are of central importance in adapting HO methods to use in CT, since the large number of pixels in a single image makes direct computation of HO performance for a full image infeasible in most cases. Reduction of the number of image pixels and/or restriction of the image to a region-of-interest (ROI) has the potential to make direct computation of HO statistics feasible in CT, provided that the signal and noise properties lead to redundant information in some regions of the image. For small signals, we hypothesize that reduction of image pixel size and enlargement of the image field-of-view are approximately equivalent means of gaining additional information relevant to a detection task. The rationale for this hypothesis is that the backprojection operation in FBP introduces long range correlations so that, for small signals, the reconstructed signal outside of a small ROI is not linearly independent of the signal within the ROI. In this work, we perform a preliminary investigation of this hypothesis by sweeping these two sampling parameters and computing HO performance for a signal detection task.

  20. Air flow assisted ionization for remote sampling of ambient mass spectrometry and its application.

    Science.gov (United States)

    He, Jiuming; Tang, Fei; Luo, Zhigang; Chen, Yi; Xu, Jing; Zhang, Ruiping; Wang, Xiaohao; Abliz, Zeper

    2011-04-15

    Ambient ionization methods are an important research area in mass spectrometry (MS) analysis. Under ambient conditions, the gas flow and atmospheric pressure significantly affect the transfer and focusing of ions. The design and implementation of air flow assisted ionization (AFAI) as a novel and effective, remote sampling method for ambient mass spectrometry are described herein. AFAI benefits from a high extracting air flow rate. A systematic investigation of the extracting air flow in the AFAI system has been carried out, and it has been demonstrated not only that it plays a role in the effective capture and remote transport of charged droplets, but also that it promotes desolvation and ion formation, and even prevents ion fragmentation during the ionization process. Moreover, the sensitivity of remote sampling ambient MS analysis was improved significantly by the AFAI method. Highly polar and nonpolar molecules, including dyes, pharmaceutical samples, explosives, drugs of abuse, protein and volatile compounds, have been successfully analyzed using AFAI-MS. The successful application of the technique to residue detection on fingers, large object analysis and remote monitoring in real time indicates its potential for the analysis of a variety of samples, especially large objects. The ability to couple this technique with most commercially available MS instruments with an API interface further enhances its broad applicability.

  1. Polyurethane foam (PUF) disks passive air samplers: Wind effect on sampling rates

    International Nuclear Information System (INIS)

    Different passive sampler housings were evaluated for their wind dampening ability and how this might translate to variability in sampler uptake rates. Polyurethane foam (PUF) disk samplers were used as the sampling medium and were exposed to a PCB-contaminated atmosphere in a wind tunnel. The effect of outside wind speed on PUF disk sampling rates was evaluated by exposing polyurethane foam (PUF) disks to a PCB-contaminated air stream in a wind tunnel over air velocities in the range 0 to 1.75 m s-1. PUF disk sampling rates increased gradually over the range 0-0.9 m s-1 at ∼4.5-14.6 m3 d-1 and then increased sharply to ∼42 m3 d-1 at ∼1.75 m s-1 (sum of PCBs). The results indicate that for most field deployments the conventional 'flying saucer' housing adequately dampens the wind effect and will yield approximately time-weighted air concentrations. - Passive sampler housings dampen wind speed and reduce the variability in sampling rates

  2. Greenhouse gas analysis of air samples collected onboard the CARIBIC passenger aircraft

    Science.gov (United States)

    Schuck, T. J.; Brenninkmeijer, C. A. M.; Slemr, F.; Xueref-Remy, I.; Zahn, A.

    2009-08-01

    CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) is a long-term atmospheric measurement program based on the use of a comprehensive scientific instrument package aboard a commercial passenger aircraft. In addition to real-time measurements, whole air sampling is performed regularly at cruising altitudes in the tropical middle troposphere and the extra-tropical UT/LS region. Air samples are analyzed for greenhouse gases, NMHCs, halocarbons, and trace gas isotopic composition. The routinely performed greenhouse gas analysis comprises gas chromatography measurements of CO2, CH4, N2O and SF6. The air sampling procedure, the GC system and its performance are described. Comparisons with similar systems employed in other laboratories and a comparison with results from a CO2 in-situ analyzer that is also part of the CARIBIC instrumentation are shown. In addition, the time series of CO2, obtained from the collection of 684 samples at latitudes between 30° N and 56° N on 21 round trips out of Germany to different destinations in Asia between November 2005 and October 2008, is presented. A time shift in the seasonal cycle of about one month was observed between the upper troposphere and the tropopause region. For two sets of return flights from Germany to the Philippines the relationship between the four greenhouse gases is briefly discussed.

  3. Portable monitors for measuring radon and its progenies air by intergrated sampling method

    International Nuclear Information System (INIS)

    Two kinds of portable monitors have been developed, which can be used to measure the concentration of radon or potential energy concentration of radon or potential energy concentration of radon progenies in air. The thermoluminescent material CaSO4(Tm) is used as a detecting element for both of them. The lowest detectable limit of the passive radon monitor is about 1.5 Bq/m3 for radon in air, as the exposure time being one week. Its main advantages are high reliability and convenient manipulation. The working level monitor for radon progenies in air consists of a mini membrane pump and an integrating probe. The lowest detectable limit is about 6.2 x 10-9 J/m3, as the sampling time being 6 hours. It weights only about 0.35 kg

  4. Detection of Legionella spp. by a nested-PCR assay in air samples of a wastewater treatment plant and downwind distances in Isfahan

    Science.gov (United States)

    Mirzaee, Seyyed Abbas; Nikaeen, Mahnaz; Hajizadeh, Yaghob; Nabavi, BiBi Fatemeh; Hassanzadeh, Akbar

    2015-01-01

    Background: Wastewater contains a variety of pathogens and bio -aerosols generated during the wastewater treatment process, which could be a potential health risk for exposed individuals. This study was carried out to detect Legionella spp. in the bio -aerosols generated from different processes of a wastewater treatment plant (WWTP) in Isfahan, Iran, and the downwind distances. Materials and Methods: A total of 54 air samples were collected and analyzed for the presence of Legionella spp. by a nested- polymerase chain reaction (PCR) assay. A liquid impingement biosampler was used to capture bio -aerosols. The weather conditions were also recorded. Results: Legionella were detected in 6% of the samples, including air samples above the aeration tank (1/9), belt filter press (1/9), and 250 m downwind (1/9). Conclusion: The result of this study revealed the presence of Legionella spp. in air samples of a WWTP and downwind distance, which consequently represent a potential health risk to the exposed individuals. PMID:25802817

  5. Evaluation of HEPA filter service life

    International Nuclear Information System (INIS)

    Rocky Flats Environmental Technology Site (RFETS), has approximately 10,000 High Efficiency Particulate Air (HEPA) Filters installed in a variety of filter plenums. These ventilation/filtration plenum systems are used to control the release of airborne particulate contaminates to the environment during normal operations and potential accidents. This report summarizes the results of destructive and non-destructive tests on HEPA filters obtained from a wide variety of ages and service conditions. These tests were performed to determine an acceptable service life criteria for HEPA filters used at Rocky Flats Environmental Technology Site (RFETS). A total of 140 filters of various ages (1972 to 1996) and service history (new, aged unused, used) were tested. For the purpose of this report, filter age from manufacture date/initial test date to the current sample date was used, as opposed to the actual time a filter was installed in an operating system

  6. Study of Air Filters in Evaporative Cooling Ventilation and Air-conditioning Unit Used in Power Plants%发电厂蒸发冷却通风空调机组空气过滤器的探讨

    Institute of Scientific and Technical Information of China (English)

    张鑫; 黄翔; 董晓杰

    2015-01-01

    通过对空气过滤器过滤机理、过滤材料以及分类的介绍,并根据蒸发冷却通风空调机组在发电厂中的应用现状,阐释了科学合理选用空气过滤器的重要性。提出为了减缓室外环境中污染物对直接(间接)蒸发冷却器换热性能的影响,应正确选择空气过滤器的类别和级数。%The air filtration theory, air filtration material and classification of air filters are introduced. Based on the current situation of evaporative cooling ventilation and air-conditioning unit used in power plants, these give a explanation of the importance of choose air filters scientifically. In order to slow the effect of evaporative cooler’s heat exchange performance by pollutant in outdoor, the classification and stage of air filters should choose correctly.

  7. Detection of Infectious Cryptosporidium parvum Oocysts in Surface and Filter Backwash Water Samples by Immunomagnetic Separation and Integrated Cell Culture-PCR

    OpenAIRE

    Di Giovanni, George D.; Hashemi, F. Helen; Shaw, Nancy J.; Abrams, Felicia A.; LeChevallier, Mark W.; Abbaszadegan, Morteza

    1999-01-01

    A new strategy for the detection of infectious Cryptosporidium parvum oocysts in water samples, which combines immunomagnetic separation (IMS) for recovery of oocysts with in vitro cell culturing and PCR (CC-PCR), was field tested with a total of 122 raw source water samples and 121 filter backwash water grab samples obtained from 25 sites in the United States. In addition, samples were processed by Percoll-sucrose flotation and oocysts were detected by an immunofluorescence assay (IFA) as a ...

  8. 14C AMS measurements of tree leaf samples to monitor air pollution induced by city traffic

    International Nuclear Information System (INIS)

    In the past, many radiocarbon measurement have been made for environmental studies such as source apportionment of air-borne particulates, and studies of the anthropogenic effects of nuclear power plants. In this presentation we report our accelerator mass spectrometry (AMS) measurements of radiocarbon on tree leaf samples to investigate the impact of city traffic on our living-environment. The fossil-burning vehicles emit carbon dioxide (CO2) free of 14C content and, when mixed with the clean air CO2, lower 14C ratio compared to the normal reservoir value. This so-called Suess effect can be incorporated to monitor air quality in our living environments, since metabolic processes maintain the 14C content of living organism in equilibrium with atmospheric 14C. In other words, dead CO2 is admixed to the normal atmospheric CO2 and then photo-synthetically assimilated by the plants. Two kinds of tree leaf samples; pine tree needles and Ginkgo tree leaves were collected during a one-week period in the summer 1996 at five different locations with various traffic conditions in the region, within a 10-km diameter circle, south of the River Han, Seoul. The AMS targets were made by a simple sample-making procedure. The leaves have been pretreated by a standard acid-alkali treatment and then charred in a vacuum evaporator by applying ca. 800 deg C heat. The charred samples were mixed with Ag powder and pressed into the Al target holder for the AMS measurement.The AMS measurements were made using the accelerator mass spectrometry facilities of the Leibniz-Labor at the Christian-Albrecht University, Kiel,Germany. The observed Δ14C values, which ranged from 60TM to 158TM, have a good correlation with the traffic conditions in the places where the sampling took place and show a remarkable capability of 14C AMS measurements to monitor our fossil burning environment. The volume ratios of clean air to air from fossil-burn origin in the environmental CO2 reached to a level of 8

  9. Optimal Media for Use in Air Sampling To Detect Cultivable Bacteria and Fungi in the Pharmacy

    OpenAIRE

    Weissfeld, Alice S.; Joseph, Riya Augustin; Le, Theresa V.; Trevino, Ernest A.; Schaeffer, M. Frances; Vance, Paula H.

    2013-01-01

    Current guidelines for air sampling for bacteria and fungi in compounding pharmacies require the use of a medium for each type of organism. U.S. Pharmacopeia (USP) chapter (http://www.pbm.va.gov/linksotherresources/docs/USP797PharmaceuticalCompoundingSterileCompounding.pdf) calls for tryptic soy agar with polysorbate and lecithin (TSApl) for bacteria and malt extract agar (MEA) for fungi. In contrast, the Controlled Environment Testing Association (CETA), the professional organization for in...

  10. Measuring Concentrations of Particulate 140La in the Air

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Colin E.; Kernan, Warnick J.; Keillor, Martin E.; Kirkham, Randy R.; Sorom, Rich D.; Van Etten, Don M.

    2016-05-01

    Air sampling systems were deployed to measure the concentration of radioactive material in the air during the Full-Scale Radiological Dispersal Device experiments. The air samplers were positioned 100-600 meters downwind of the release point. The filters were collected immediately and analyzed in the field. Quantities for total activity collected on the air filters are reported along with additional information to compute the average or integrated air concentrations.

  11. Isotopic air sampling in a tallgrass prairie to partition net ecosystem CO2 exchange

    Science.gov (United States)

    Lai, Chun-Ta; Schauer, Andrew J.; Owensby, Clenton; Ham, Jay M.; Ehleringer, James R.

    2003-09-01

    Stable isotope ratios of various ecosystem components and net ecosystem exchange (NEE) CO2 fluxes were measured in a C3-C4 mixture tallgrass prairie near Manhattan, Kansas. The July 2002 study period was chosen because of contrasting soil moisture contents, which allowed us to address the effects of drought on photosynthetic CO2 uptake and isotopic discrimination. Significantly higher NEE fluxes were observed for both daytime uptake and nighttime respiration during well-watered conditions when compared to a drought period. Given these differences, we investigated two carbon-flux partitioning questions: (1) What proportions of NEE were contributed by C3 versus C4 species? (2) What proportions of NEE fluxes resulted from canopy assimilation versus ecosystem respiration? To evaluate these questions, air samples were collected every 2 hours during daytime for 3 consecutive days at the same height as the eddy covariance system. These air samples were analyzed for both carbon isotope ratios and CO2 concentrations to establish an empirical relationship for isoflux calculations. An automated air sampling system was used to collect nighttime air samples to estimate the carbon isotope ratios of ecosystem respiration (δR) at weekly intervals for the entire growing season. Models of C3 and C4 photosynthesis were employed to estimate bulk canopy intercellular CO2 concentration in order to calculate photosynthetic discrimination against 13C. Our isotope/NEE results showed that for this grassland, C4 vegetation contributed ˜80% of the NEE fluxes during the drought period and later ˜100% of the NEE fluxes in response to an impulse of intense precipitation. For the entire growing season, the C4 contribution ranged from ˜68% early in the spring to nearly 100% in the late summer. Using an isotopic approach, the calculated partitioned respiratory fluxes were slightly greater than chamber-measured estimates during midday under well-watered conditions. In addition, time series

  12. Measurement of the Tracer Gradient and Sampling System Bias of the Hot Fuel Examination Facility Stack Air Monitoring System

    Energy Technology Data Exchange (ETDEWEB)

    Glissmeyer, John A.; Flaherty, Julia E.

    2011-07-20

    This report describes tracer gas uniformity and bias measurements made in the exhaust air discharge of the Hot Fuel Examination Facility at Idaho National Laboratory. The measurements were a follow-up on earlier measurements which indicated a lack of mixing of the two ventilation streams being discharged via a common stack. The lack of mixing is detrimental to the accuracy of air emission measurements. The lack of mixing was confirmed in these new measurements. The air sampling probe was found to be out of alignment and that was corrected. The suspected sampling bias in the air sample stream was disproved.

  13. Analysis of non-methane hydrocarbons in air samples collected aboard the CARIBIC passenger aircraft

    Directory of Open Access Journals (Sweden)

    A. K. Baker

    2009-10-01

    Full Text Available The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container is a long-term monitoring program making regular atmospheric measurements from an instrument container installed monthly aboard a passenger aircraft. Typical cruising altitudes of the aircraft allow for the study of the free troposphere and the extra-tropical upper troposphere as well as the lowermost stratosphere. CARIBIC measurements include a number of real time analyses as well as the collection of aerosol and whole air samples. These whole air samples are analyzed post-flight for a suite of trace gases, which includes non-methane hydrocarbons (NMHC.

    The NMHC measurement system and its analytical performance are described here. Precision was found to vary slightly by compound, and is less than 2% for the C2–C6 alkanes and ethyne, and between 1 and 6% for C7–C8 alkanes and aromatic compounds. Preliminary results from participation in a Global Atmospheric Watch (WMO VOC audit indicate accuracies within the precision of the system. Limits of detection are 1 pptv for most compounds, and up to 3 pptv for some aromatics. These are sufficiently low to measure mixing ratios typically observed in the upper troposphere and lowermost stratosphere for the longer-lived NMHC, however, in air samples from these regions many of the compounds with shorter lifetimes (<5 d were frequently below the detection limit. Observed NMHC concentrations span many orders of magnitude, dependent on atmospheric region and air mass history, with concentrations typically decreasing with shorter chemical lifetimes.

  14. Sorbent-based sampling methods for volatile and semi-volatile organic compounds in air Part 1: Sorbent-based air monitoring options.

    Science.gov (United States)

    Woolfenden, Elizabeth

    2010-04-16

    Sorbent tubes/traps are widely used in combination with gas chromatographic (GC) analytical methods to monitor the vapour-phase fraction of organic compounds in air. Target compounds range in volatility from acetylene and freons to phthalates and PCBs and include apolar, polar and reactive species. Airborne vapour concentrations will vary depending on the nature of the location, nearby pollution sources, weather conditions, etc. Levels can range from low percent concentrations in stack and vent emissions to low part per trillion (ppt) levels in ultra-clean outdoor locations. Hundreds, even thousands of different compounds may be present in any given atmosphere. GC is commonly used in combination with mass spectrometry (MS) detection especially for environmental monitoring or for screening uncharacterised workplace atmospheres. Given the complexity and variability of organic vapours in air, no one sampling approach suits every monitoring scenario. A variety of different sampling strategies and sorbent media have been developed to address specific applications. Key sorbent-based examples include: active (pumped) sampling onto tubes packed with one or more sorbents held at ambient temperature; diffusive (passive) sampling onto sorbent tubes/cartridges; on-line sampling of air/gas streams into cooled sorbent traps; and transfer of air samples from containers (canisters, Tedlar) bags, etc.) into cooled sorbent focusing traps. Whichever sampling approach is selected, subsequent analysis almost always involves either solvent extraction or thermal desorption (TD) prior to GC(/MS) analysis. The overall performance of the air monitoring method will depend heavily on appropriate selection of key sampling and analytical parameters. This comprehensive review of air monitoring using sorbent tubes/traps is divided into 2 parts. (1) Sorbent-based air sampling option. (2) Sorbent selection and other aspects of optimizing sorbent-based air monitoring methods. The paper presents

  15. Comparison of air samples, nasal swabs, ear-skin swabs and environmental dust samples for detection of Methicillin Resistant Staphylococcus aureus (MRSA) in pig herds

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Vigre, Håkan; Cavaco, Lina;

    2014-01-01

    To identify a cost-effective and practical method for detection of methicillin-resistant Staphylococcus aureus (MRSA) in pig herds, the relative sensitivity of four sample types: nasal swabs, ear-skin (skin behind the ears) swabs, environmental dust swabs and air was compared. Moreover, dependency...... detection by air sampling is easy to perform, reduces costs and analytical time compared to existing methods, and is recommended for initial testing of herds. Ear-skin swab sampling may be more sensitive for MRSA detection than air sampling or nasal swab sampling.......-herd prevalence ⩾25%]. The results indicate that taking swabs of skin behind the ears (ten pools of five) was even more sensitive than taking nasal swabs (ten pools of five) at the herd level and detected significantly more positive samples. spa types t011, t034 and t4208 were observed. In conclusion, MRSA...

  16. Biomimetic air sampling for detection of low concentrations of molecules and bioagents : LDRD 52744 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Robert Clark

    2003-12-01

    Present methods of air sampling for low concentrations of chemicals like explosives and bioagents involve noisy and power hungry collectors with mechanical parts for moving large volumes of air. However there are biological systems that are capable of detecting very low concentrations of molecules with no mechanical moving parts. An example is the silkworm moth antenna which is a highly branched structure where each of 100 branches contains about 200 sensory 'hairs' which have dimensions of 2 microns wide by 100 microns long. The hairs contain about 3000 pores which is where the gas phase molecules enter the aqueous (lymph) phase for detection. Simulations of diffusion of molecules indicate that this 'forest' of hairs is 'designed' to maximize the extraction of the vapor phase molecules. Since typical molecules lose about 4 decades in diffusion constant upon entering the liquid phase, it is important to allow air diffusion to bring the molecule as close to the 'sensor' as possible. The moth acts on concentrations as low as 1000 molecules per cubic cm. (one part in 1e16). A 3-D collection system of these dimensions could be fabricated by micromachining techniques available at Sandia. This LDRD addresses the issues involved with extracting molecules from air onto micromachined structures and then delivering those molecules to microsensors for detection.

  17. CARBONIZED FIBROUS RESIN AS A NEW SORBENT FOR SAMPLING POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) IN AMBIENT AIR

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new sampling method of ambient air analysis using carbonized fibrous resin as asorbent for polycyclic aromatic hydrocarbons (PAHs) was reported.The physical and chemical properties of the carbonized fibrous resins were measured. Thesample pretreatment with ultrasonic extraction and subsequent clean-up ehition through a silica gelcolumn was optimized. The suitable ultrasonic extraction conditions were selected as follows: resinweight was 1.5 g, ultrasonic extraction time 20 min, volume of extraction solvent 100 mi andextraction operation times 2~3. The concentrated extractable organic matter was submitted to nextstep of clean-up procedure of adsorption chromatography on silica gel column/n-hexane and amixture of dichloromethene:n-hexane solution 2:3 (v/v). The PAHs fractions in the real samplesfrom Changzhou, China were particularly analyzed using GC-MS data system and the data of massspectra, retention times and scan numbers of the real samples were compared with that of thestandards of 16 PAHs listed by the US EPA as "priority pollutants" of the environment. Theanalysis of the real samples indicates that the carbonized fibrous resin is a good sorbent. Thepretreatment of samples of ambient air with carbonized fibrous resin as a sorbent for P,AHs isproved to be reliable and might be used for the procedure of the determination of PAHs inatmospheric environment.

  18. Mass spectrometry of solid samples in open air using combined laser ionization and ambient metastable ionization

    Science.gov (United States)

    He, X. N.; Xie, Z. Q.; Gao, Y.; Hu, W.; Guo, L. B.; Jiang, L.; Lu, Y. F.

    2012-01-01

    Mass spectrometry of solid samples in open air was carried out using combined laser ionization and metastable ionization time-of-flight mass spectrometry (LI-MI-TOFMS) in ambient environment for qualitative and semiquantitative (relative analyte information, not absolute information) analysis. Ambient metastable ionization using a direct analysis in realtime (DART) ion source was combined with laser ionization time-of-flight mass spectrometry (LI-TOFMS) to study the effects of combining metastable and laser ionization. A series of metallic samples from the National Institute of Standards and Technology (NIST 494, 495, 498, 499, and 500) and a pure carbon target were characterized using LI-TOFMS in open air. LI-MI-TOFMS was found to be superior to laser-induced breakdown spectroscopy (LIBS). Laser pulse energies between 10 and 200 mJ at the second harmonic (532 nm) of an Nd:YAG laser were applied in the experiment to obtain a high degree of ionization in plasmas. Higher laser pulse energy improves signal intensities of trace elements (such as Fe, Cr, Mn, Ni, Ca, Al, and Ag). Data were analyzed by numerically calculating relative sensitivity coefficients (RSCs) and limit of detections (LODs) from mass spectrometry (MS) and LIBS spectra. Different parameters, such as boiling point, ionization potential, RSC, LOD, and atomic weight, were shown to analyze the ionization and MS detection processes in open air.

  19. Glyphosate-rich air samples induce IL-33, TSLP and generate IL-13 dependent airway inflammation.

    Science.gov (United States)

    Kumar, Sudhir; Khodoun, Marat; Kettleson, Eric M; McKnight, Christopher; Reponen, Tiina; Grinshpun, Sergey A; Adhikari, Atin

    2014-11-01

    Several low weight molecules have often been implicated in the induction of occupational asthma. Glyphosate, a small molecule herbicide, is widely used in the world. There is a controversy regarding a role of glyphosate in developing asthma and rhinitis among farmers, the mechanism of which is unexplored. The aim of this study was to explore the mechanisms of glyphosate induced pulmonary pathology by utilizing murine models and real environmental samples. C57BL/6, TLR4-/-, and IL-13-/- mice inhaled extracts of glyphosate-rich air samples collected on farms during spraying of herbicides or inhaled different doses of glyphosate and ovalbumin. The cellular response, humoral response, and lung function of exposed mice were evaluated. Exposure to glyphosate-rich air samples as well as glyphosate alone to the lungs increased: eosinophil and neutrophil counts, mast cell degranulation, and production of IL-33, TSLP, IL-13, and IL-5. In contrast, in vivo systemic IL-4 production was not increased. Co-administration of ovalbumin with glyphosate did not substantially change the inflammatory immune response. However, IL-13-deficiency resulted in diminished inflammatory response but did not have a significant effect on airway resistance upon methacholine challenge after 7 or 21 days of glyphosate exposure. Glyphosate-rich farm air samples as well as glyphosate alone were found to induce pulmonary IL-13-dependent inflammation and promote Th2 type cytokines, but not IL-4 for glyphosate alone. This study, for the first time, provides evidence for the mechanism of glyphosate-induced occupational lung disease.

  20. Size selective isocyanate aerosols personal air sampling using porous plastic foams

    Science.gov (United States)

    Khanh Huynh, Cong; Duc, Trinh Vu

    2009-02-01

    As part of a European project (SMT4-CT96-2137), various European institutions specialized in occupational hygiene (BGIA, HSL, IOM, INRS, IST, Ambiente e Lavoro) have established a program of scientific collaboration to develop one or more prototypes of European personal samplers for the collection of simultaneous three dust fractions: inhalable, thoracic and respirable. These samplers based on existing sampling heads (IOM, GSP and cassettes) use Polyurethane Plastic Foam (PUF) according to their porosity to support sampling and separator size of the particles. In this study, the authors present an original application of size selective personal air sampling using chemical impregnated PUF to perform isocyanate aerosols capturing and derivatizing in industrial spray-painting shops.

  1. A Technical Discussion on the Use of Air Filter%关于过滤器使用的一些技术探讨

    Institute of Scientific and Technical Information of China (English)

    王健; 汪洪军

    2011-01-01

    Based on the technical sum up of using air filter in the construction and operation of the cleanroom in changping campus of National institute ofmetrology(NIM),the experience and ideas which show the performance, efficiency, life-span and its judgement of air filter are abstracted, especially the big filter material square and one-off first filter are better plan.%对中国计量科学研究院(NIM)某实验基地在洁净室建设和运行过程中过滤器的使用方面进行了一些技术探讨,根据实际经验和看法对过滤器的性能和效率、使用寿命及其评判标准进行了技术总结,并提出选择滤料面积大的过滤器和一次性初效过滤器是性价比较高的技术方案。

  2. Estimating surface CO2 fluxes from space-borne CO2 dry air mole fraction observations using an ensemble Kalman Filter

    Directory of Open Access Journals (Sweden)

    S. Dance

    2008-11-01

    Full Text Available We have developed an ensemble Kalman Filter (EnKF to estimate 8-day regional surface fluxes of CO2 from space-borne CO2 dry-air mole fraction observations (XCO2 and evaluate the approach using a series of synthetic experiments, in preparation for data from the NASA Orbiting Carbon Observatory (OCO. The 32-day duty cycle of OCO alternates every 16 days between nadir and glint measurements of backscattered solar radiation at short-wave infrared wavelengths. The EnKF uses an ensemble of states to represent the prior error covariance to estimate 8-day CO2 surface fluxes over 144 geographical regions. We use a 12×8-day lag window, recognising that XCO2 measurements include surface flux information from prior time windows. The observation operator that relates surface CO2 fluxes to atmospheric distributions of XCO2 includes: a the GEOS-Chem transport model that relates surface fluxes to global 3-D distributions of CO2 concentrations, which are sampled at the time and location of OCO measurements that are cloud-free and have aerosol optical depths 2 profiles to XCO2, accounting for differences between nadir and glint measurements, and the associated scene-dependent observation errors. We show that OCO XCO2 measurements significantly reduce the uncertainties of surface CO2 flux estimates. Glint measurements are generally better at constraining ocean CO2 flux estimates. Nadir XCO2 measurements over the terrestrial tropics are sparse throughout the year because of either clouds or smoke. Glint measurements provide the most effective constraint for estimating tropical terrestrial CO2 fluxes by accurately sampling fresh continental outflow over neighbouring oceans. We also present results from sensitivity experiments that investigate how flux estimates change with 1 bias and unbiased errors, 2 alternative duty cycles, 3 measurement density and correlations, 4 the spatial resolution of estimated flux estimates, and 5 reducing the length of the lag window

  3. Residues of 2, 4-D in air samples from Saskatchewan: 1966-1975.

    Science.gov (United States)

    Grover, R; Kerr, L A; Wallace, K; Yoshida, K; Maybank, J

    1976-01-01

    Residues of 2,4-D (2,4-dichlorophenoxyacetic acid) in air samples from several sampling sites in central and southern Saskatchewan during the spraying seasons in the 1966-68 and 1970-75 periods were determined by gas-liquid chromatographic techniques. Initially, individual esters of 2,4-D were characterized by retention times and confirmed further by co-injection and dual column procedures. Since 1973, however, only total 2,4-D acid levels in air samples have been determined after esterification to the methyl ester and confirmed by gc/ms techniques whenever possible. Up to 50% of the daily samples collected during the spraying season at any of the locations and during any given year contained 2,4-D, with butyl esters being found most frequently. The daily 24-hr mean atmospheric concentrations of 2,4-D ranged from 0.01 to 1.22 mug/m3, 0.01 to 13.50 mug/m3, and 0.05 to 0.59 mug/m3 for the iso-propyl, mixed butyl and iso-octyl esters, respectively. Even when the samples were analysed for the total 2,4-D content, i.e. from 1973 onwards, the maximum level of the total acid reached only 23.14 mug/m3. In any given year and at any of the sampling sites, about 30% of the samples contained less than 0.01 mug/m3 of 2,4-D. In another 40% of the samples, the levels of 2,4-D ranged from 0.01 to 0.099 mug/m3. Only about 30% of the samples contained 2,4-D concentrations higher than 0.1 mug/m3, with only 10% or less exceeding 1 mug/m3. None of the samples, obtained with the high volume particulate sampler, showed any detectable levels of 2,4-D, indicating little or no transport of 2,4-D adsorbed on dust particles or as crystals of amine salts. PMID:1002953

  4. Accurate quantification of tio2 nanoparticles collected on air filters using a microwave-assisted acid digestion method.

    Science.gov (United States)

    Mudunkotuwa, Imali A; Anthony, T Renée; Grassian, Vicki H; Peters, Thomas M

    2016-01-01

    Titanium dioxide (TiO(2)) particles, including nanoparticles with diameters smaller than 100 nm, are used extensively in consumer products. In a 2011 current intelligence bulletin, the National Institute of Occupational Safety and Health (NIOSH) recommended methods to assess worker exposures to fine and ultrafine TiO(2) particles and associated occupational exposure limits for these particles. However, there are several challenges and problems encountered with these recommended exposure assessment methods involving the accurate quantitation of titanium dioxide collected on air filters using acid digestion followed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Specifically, recommended digestion methods include the use of chemicals, such as perchloric acid, which are typically unavailable in most accredited industrial hygiene laboratories due to highly corrosive and oxidizing properties. Other alternative methods that are used typically involve the use of nitric acid or combination of nitric acid and sulfuric acid, which yield very poor recoveries for titanium dioxide. Therefore, given the current state of the science, it is clear that a new method is needed for exposure assessment. In this current study, a microwave-assisted acid digestion method has been specifically designed to improve the recovery of titanium in TiO(2) nanoparticles for quantitative analysis using ICP-OES. The optimum digestion conditions were determined by changing several variables including the acids used, digestion time, and temperature. Consequently, the optimized digestion temperature of 210°C with concentrated sulfuric and nitric acid (2:1 v/v) resulted in a recovery of >90% for TiO(2). The method is expected to provide for a more accurate quantification of airborne TiO(2) particles in the workplace environment. PMID:26181824

  5. Charge-Domain Signal Processing of Direct RF Sampling Mixer with Discrete-Time Filters in Bluetooth and GSM Receivers

    Directory of Open Access Journals (Sweden)

    Ho Yo-Chuol

    2006-01-01

    Full Text Available RF circuits for multi-GHz frequencies have recently migrated to low-cost digital deep-submicron CMOS processes. Unfortunately, this process environment, which is optimized only for digital logic and SRAM memory, is extremely unfriendly for conventional analog and RF designs. We present fundamental techniques recently developed that transform the RF and analog circuit design complexity to digitally intensive domain for a wireless RF transceiver, so that it enjoys benefits of digital and switched-capacitor approaches. Direct RF sampling techniques allow great flexibility in reconfigurable radio design. Digital signal processing concepts are used to help relieve analog design complexity, allowing one to reduce cost and power consumption in a reconfigurable design environment. The ideas presented have been used in Texas Instruments to develop two generations of commercial digital RF processors: a single-chip Bluetooth radio and a single-chip GSM radio. We further present details of the RF receiver front end for a GSM radio realized in a 90-nm digital CMOS technology. The circuit consisting of low-noise amplifier, transconductance amplifier, and switching mixer offers dB dynamic range with digitally configurable voltage gain of 40 dB down to dB. A series of decimation and discrete-time filtering follows the mixer and performs a highly linear second-order lowpass filtering to reject close-in interferers. The front-end gains can be configured with an automatic gain control to select an optimal setting to form a trade-off between noise figure and linearity and to compensate the process and temperature variations. Even under the digital switching activity, noise figure at the 40 dB maximum gain is 1.8 dB and dBm IIP2 at the 34 dB gain. The variation of the input matching versus multiple gains is less than 1 dB. The circuit in total occupies 3.1 . The LNA, TA, and mixer consume less than mA at a supply voltage of 1.4 V.

  6. Charge-Domain Signal Processing of Direct RF Sampling Mixer with Discrete-Time Filters in Bluetooth and GSM Receivers

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available RF circuits for multi-GHz frequencies have recently migrated to low-cost digital deep-submicron CMOS processes. Unfortunately, this process environment, which is optimized only for digital logic and SRAM memory, is extremely unfriendly for conventional analog and RF designs. We present fundamental techniques recently developed that transform the RF and analog circuit design complexity to digitally intensive domain for a wireless RF transceiver, so that it enjoys benefits of digital and switched-capacitor approaches. Direct RF sampling techniques allow great flexibility in reconfigurable radio design. Digital signal processing concepts are used to help relieve analog design complexity, allowing one to reduce cost and power consumption in a reconfigurable design environment. The ideas presented have been used in Texas Instruments to develop two generations of commercial digital RF processors: a single-chip Bluetooth radio and a single-chip GSM radio. We further present details of the RF receiver front end for a GSM radio realized in a 90-nm digital CMOS technology. The circuit consisting of low-noise amplifier, transconductance amplifier, and switching mixer offers 32.5 dB dynamic range with digitally configurable voltage gain of 40 dB down to 7.5 dB. A series of decimation and discrete-time filtering follows the mixer and performs a highly linear second-order lowpass filtering to reject close-in interferers. The front-end gains can be configured with an automatic gain control to select an optimal setting to form a trade-off between noise figure and linearity and to compensate the process and temperature variations. Even under the digital switching activity, noise figure at the 40 dB maximum gain is 1.8 dB and +50 dBm IIP2 at the 34 dB gain. The variation of the input matching versus multiple gains is less than 1 dB. The circuit in total occupies 3.1 mm 2 . The LNA, TA, and mixer consume less than 15.3 mA at a supply voltage of 1.4 V.

  7. A comparison of surface water natural organic matter in raw filtered water samples, XAD, and reverse osmosis isolates

    Science.gov (United States)

    Maurice, P.A.; Pullin, M.J.; Cabaniss, S.E.; Zhou, Q.; Namjesnik-Dejanovic, K.; Aiken, G.R.

    2002-01-01

    This research compared raw filtered waters (RFWs), XAD resin isolates (XAD-8 and XAD-4), and reverse osmosis (RO) isolates of several surface water samples from McDonalds Branch, a small freshwater fen in the New Jersey Pine Barrens (USA). RO and XAD-8 are two of the most common techniques used to isolate natural organic matter (NOM) for studies of composition and reactivity; therefore, it is important to understand how the isolates differ from bulk (unisolated) samples and from one another. Although, any comparison between the isolation methods needs to consider that XAD-8 is specifically designed to isolate the humic fraction, whereas RO concentrates a broad range of organic matter and is not specific to humics. The comparison included for all samples: weight average molecular weight (Mw), number average molecular weight (Mn), polydispersity (??), absorbance at 280nm normalized to moles C (??280) (RFW and isolates); and for isolates only: elemental analysis, % carbon distribution by 13C NMR, and aqueous FTIR spectra. As expected, RO isolation gave higher yield of NOM than XAD-8, but also higher ash content, especially Si and S. Mw decreased in the order: RO>XAD-8>RFW>XAD-4. The Mw differences of isolates compared with RFW may be due to selective isolation (fractionation), or possibly in the case of RO to condensation or coagulation during isolation. 13C NMR results were roughly similar for the two methods, but the XAD-8 isolate was slightly higher in 'aromatic' C and the RO isolate was slightly higher in heteroaliphatic and carbonyl C. Infrared spectra indicated a higher carboxyl content for the XAD-8 isolates and a higher ester:carboxyl ratio for the RO isolates. The spectroscopic data thus are consistent with selective isolation of more hydrophobic compounds by XAD-8, and also with potential ester hydrolysis during that process, although further study is needed to determine whether ester hydrolysis does indeed occur. Researchers choosing between XAD and RO

  8. Flow resistance of HEPA filters in supersaturated airstreams

    International Nuclear Information System (INIS)

    A loss of coolant accident or fire suppression with water sprays would release free moisture into the air within the containment building of a nuclear reactor. The resulting high air humidity could be expected to unfavorably affect the behavior of the HEPA filters in the facility air cleaning systems. Still to be found in the literature are instances of moisture related deterioration in filter performance during less serious incidents, and even during normal operations. One phenomenon which contributes to filter failure, and which also causes air-cleaning system malfunction characterized by drastically reduced flow rates, is the increase in filter differential pressure resulting from supersaturated airflow. In order to better evaluate the performance and the reliability of filters exposed to fog, a study of the factors which influence filter pressure drop was carried out in tests of clean and dust loaded full scale HEPA-filter units. Investigated were the effects of several airstream parameters and such filter characteristics as manufacturer, design, pack geometry, extent and type of dust loading, as well as pleat orientation to the airflow. A discontinuous gravimetric method employing full-size filter units as sampling filters was successfully implemented to determine the average liquid moisture content of the airstream with an uncertainty of ≤10%. The dust loading in filters removed from service and the liquid moisture content of the air proved to most adversely affect the rate and extent of the pressure drop increase. Reductions in the susceptibility of clean filters to pressure drop increases can be obtained by changes in filter geometry, design or orientation to the airflow that enhance the drainage of water from the filter medium. However, the predominance of the adverse influence of dust loading appears to be able to counteract the effectiveness of the improvements studied

  9. Impact of Filter Paper Multilayering on Air Permeability%滤纸多层复合对透气率的影响

    Institute of Scientific and Technical Information of China (English)

    黄铖; 曾靖山; 梁云; 沈栋

    2011-01-01

    The relationship of the air permeability between the single-layer and multi-layer composite filter paper was studied. The multi-layer composite filter paper was made by placed the single-layer wet sheet close together in a certain order and dried in the Arc dryer, and the relationship of the air permeability between the double(triple) composite filter paper and its every single-layer at the case that each layer was composed of a single fiber or various fibers was researched. By the research we deduce the relationship between the air permeability of multi-layer composite filter paper and the air permeability of single-layer filter paper as follows: 1/T=1/T1+1/T2 +... +1/T11, which would provide instructional information for the study of multi-layer composite filter paper.%研究多层复合滤纸和单层滤纸间透气率的关系:通过将单层湿纸页按一定顺序紧密叠合在一起并放入弧形干燥器内干燥的方法形成多层复合滤纸,探讨当各层纤维为单一纤维和多种纤维复配两种情况下的2层和3层复合滤纸的透气率与各单层滤纸透气率之间的关系,并从理论上推导出多层复合滤纸和单层滤纸间透气率存在如下关系:1/T=1/T1+1/T2+…+1/T11,这对多层复合滤纸的研究有一定的指导意义。

  10. Cast Stone Oxidation Front Evaluation: Preliminary Results For Samples Exposed To Moist Air

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. A.; Almond, P. M.

    2013-11-26

    The rate of oxidation is important to the long-term performance of reducing salt waste forms because the solubility of some contaminants, e.g., technetium, is a function of oxidation state. TcO{sub 4}{sup -} in the salt solution is reduced to Tc(IV) and has been shown to react with ingredients in the waste form to precipitate low solubility sulfide and/or oxide phases. Upon exposure to oxygen, the compounds containing Tc(IV) oxidize to the pertechnetate ion, Tc(VII)O{sub 4}{sup -}, which is very soluble. Consequently the rate of technetium oxidation front advancement into a monolith and the technetium leaching profile as a function of depth from an exposed surface are important to waste form performance and ground water concentration predictions. An approach for measuring contaminant oxidation rate (effective contaminant specific oxidation rate) based on leaching of select contaminants of concern is described in this report. In addition, the relationship between reduction capacity and contaminant oxidation is addressed. Chromate (Cr(VI) was used as a non-radioactive surrogate for pertechnetate, Tc(VII), in Cast Stone samples prepared with 5 M Simulant. Cast Stone spiked with pertechnetate was also prepared and tested. Depth discrete subsamples spiked with Cr were cut from Cast Stone exposed to Savannah River Site (SRS) outdoor ambient temperature fluctuations and moist air. Depth discrete subsamples spiked with Tc-99 were cut from Cast Stone exposed to laboratory ambient temperature fluctuations and moist air. Similar conditions are expected to be encountered in the Cast Stone curing container. The leachability of Cr and Tc-99 and the reduction capacities, measured by the Angus-Glasser method, were determined for each subsample as a function of depth from the exposed surface. The results obtained to date were focused on continued method development and are preliminary and apply to the sample composition and curing / exposure conditions described in this report. The

  11. Ram-air sample collection device for a chemical warfare agent sensor

    Science.gov (United States)

    Megerle, Clifford A.; Adkins, Douglas R.; Frye-Mason, Gregory C.

    2002-01-01

    In a surface acoustic wave sensor mounted within a body, the sensor having a surface acoustic wave array detector and a micro-fabricated sample preconcentrator exposed on a surface of the body, an apparatus for collecting air for the sensor, comprising a housing operatively arranged to mount atop the body, the housing including a multi-stage channel having an inlet and an outlet, the channel having a first stage having a first height and width proximate the inlet, a second stage having a second lower height and width proximate the micro-fabricated sample preconcentrator, a third stage having a still lower third height and width proximate the surface acoustic wave array detector, and a fourth stage having a fourth height and width proximate the outlet, where the fourth height and width are substantially the same as the first height and width.

  12. Utilizing the partitioning properties of silicone for the passive sampling of polychlorinated biphenyls (PCBs) in indoor air

    DEFF Research Database (Denmark)

    Vorkamp, Katrin; Odsbjerg, Lisbeth; Langeland, Majbrith;

    2016-01-01

    coefficients, but further research is required for the determination of silicone-air partition coefficients. Avoiding performance reference compounds (PRCs) because of the indoor setting, the two formats were calibrated against conventional active measurements. Comparisons of air concentrations derived from......The former use of polychlorinated biphenyls (PCBs) in construction materials can lead to elevated indoor air concentrations. We studied the partitioning of PCB congeners between indoor air and silicone with a view to establish passive sampling of PCBs. The release of PCB congeners from silicone......) in a petri dish, while PCBs reached equilibrium in silicone-coated paper sheets (0.001 mm silicone on each side) exposed to indoor air for 1–2 weeks. The ratios of equilibrium concentrations in silicone and conventionally measured air concentrations were roughly comparable with silicone-air partition...

  13. The Successful Diagnosis and Typing of Systemic Amyloidosis Using A Microwave-Assisted Filter-Aided Fast Sample Preparation Method and LC/MS/MS Analysis

    OpenAIRE

    Weiyi Sun; Jian Sun; Lili Zou; Kaini Shen; Dingrong Zhong; Daobin Zhou; Wei Sun; Jian Li

    2015-01-01

    Laser microdissection followed by mass spectrometry has been successfully used for amyloid typing. However, sample contamination can interfere with proteomic analysis, and overnight digestion limits the analytical throughput. Moreover, current quantitative analysis methods are based on the spectrum count, which ignores differences in protein length and may lead to misdiagnoses. Here, we developed a microwave-assisted filter-aided sample preparation (maFASP) method that can efficiently remove ...

  14. Comparison of Hollow-Fiber Ultrafilters with Pleated Capsule Filters for Surface and Tap Water Samples Using U.S. EPA Method 1623

    OpenAIRE

    Kimble, Gina H.; Amburgey, James E.; Hill, Vincent R.

    2012-01-01

    The EPA method 1623 is designed specifically for the detection of Cryptosporidium and Giardia, but the method has some issues with low and variable recoveries. Ultrafiltration has been used effectively for microorganism recovery from water samples but is not approved by the EPA. To determine the efficacy of using ultrafiltration, 10-L tap water and surface water samples were seeded with Cryptosporidium and Giardia and concentrated with either a pleated capsule filter or a hollow-fiber ultrafi...

  15. Soil separator and sampler and method of sampling

    Science.gov (United States)

    O'Brien, Barry H [Idaho Falls, ID; Ritter, Paul D [Idaho Falls, ID

    2010-02-16

    A soil sampler includes a fluidized bed for receiving a soil sample. The fluidized bed may be in communication with a vacuum for drawing air through the fluidized bed and suspending particulate matter of the soil sample in the air. In a method of sampling, the air may be drawn across a filter, separating the particulate matter. Optionally, a baffle or a cyclone may be included within the fluidized bed for disentrainment, or dedusting, so only the finest particulate matter, including asbestos, will be trapped on the filter. The filter may be removable, and may be tested to determine the content of asbestos and other hazardous particulate matter in the soil sample.

  16. Further studies of oxidation processes on filter surfaces: Evidence for oxidation products and the influence of time in service

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Clausen, Geo; Weschler, Charles J.

    2007-01-01

    efficiencies than an identical filter not protected from ozone during the same 9 weeks of service filtering the same air. This result indicates that a filter's exposure history subsequently influences the quantity of oxidation products generated when ozone-containing air flows through it. (c) 2007 Elsevier Ltd...... understanding of such processes. The measured ratio of downstream to upstream submicron particle concentrations increased when ozone was added to air passing through samples from loaded particle filters. Such an observation is consistent with low volatility oxidation products desorbing from the filter...

  17. Remotely serviced filter and housing

    Science.gov (United States)

    Ross, M.J.; Zaladonis, L.A.

    1987-07-22

    A filter system for a hot cell comprises a housing adapted for input of air or other gas to be filtered, flow of the air through a filter element, and exit of filtered air. The housing is tapered at the top to make it easy to insert a filter cartridge holds the filter element while the air or other gas is passed through the filter element. Captive bolts in trunnion nuts are readily operated by electromechanical manipulators operating power wrenches to secure and release the filter cartridge. The filter cartridge is adapted to make it easy to change a filter element by using a master-slave manipulator at a shielded window station. 6 figs.

  18. Evaluation of sampling methods for toxicological testing of indoor air particulate matter.

    Science.gov (United States)

    Tirkkonen, Jenni; Täubel, Martin; Hirvonen, Maija-Riitta; Leppänen, Hanna; Lindsley, William G; Chen, Bean T; Hyvärinen, Anne; Huttunen, Kati

    2016-09-01

    There is a need for toxicity tests capable of recognizing indoor environments with compromised air quality, especially in the context of moisture damage. One of the key issues is sampling, which should both provide meaningful material for analyses and fulfill requirements imposed by practitioners using toxicity tests for health risk assessment. We aimed to evaluate different existing methods of sampling indoor particulate matter (PM) to develop a suitable sampling strategy for a toxicological assay. During three sampling campaigns in moisture-damaged and non-damaged school buildings, we evaluated one passive and three active sampling methods: the Settled Dust Box (SDB), the Button Aerosol Sampler, the Harvard Impactor and the National Institute for Occupational Safety and Health (NIOSH) Bioaerosol Cyclone Sampler. Mouse RAW264.7 macrophages were exposed to particle suspensions and cell metabolic activity (CMA), production of nitric oxide (NO) and tumor necrosis factor (TNFα) were determined after 24 h of exposure. The repeatability of the toxicological analyses was very good for all tested sampler types. Variability within the schools was found to be high especially between different classrooms in the moisture-damaged school. Passively collected settled dust and PM collected actively with the NIOSH Sampler (Stage 1) caused a clear response in exposed cells. The results suggested the higher relative immunotoxicological activity of dust from the moisture-damaged school. The NIOSH Sampler is a promising candidate for the collection of size-fractionated PM to be used in toxicity testing. The applicability of such sampling strategy in grading moisture damage severity in buildings needs to be developed further in a larger cohort of buildings.

  19. Evaluation of sampling methods for toxicological testing of indoor air particulate matter.

    Science.gov (United States)

    Tirkkonen, Jenni; Täubel, Martin; Hirvonen, Maija-Riitta; Leppänen, Hanna; Lindsley, William G; Chen, Bean T; Hyvärinen, Anne; Huttunen, Kati

    2016-09-01

    There is a need for toxicity tests capable of recognizing indoor environments with compromised air quality, especially in the context of moisture damage. One of the key issues is sampling, which should both provide meaningful material for analyses and fulfill requirements imposed by practitioners using toxicity tests for health risk assessment. We aimed to evaluate different existing methods of sampling indoor particulate matter (PM) to develop a suitable sampling strategy for a toxicological assay. During three sampling campaigns in moisture-damaged and non-damaged school buildings, we evaluated one passive and three active sampling methods: the Settled Dust Box (SDB), the Button Aerosol Sampler, the Harvard Impactor and the National Institute for Occupational Safety and Health (NIOSH) Bioaerosol Cyclone Sampler. Mouse RAW264.7 macrophages were exposed to particle suspensions and cell metabolic activity (CMA), production of nitric oxide (NO) and tumor necrosis factor (TNFα) were determined after 24 h of exposure. The repeatability of the toxicological analyses was very good for all tested sampler types. Variability within the schools was found to be high especially between different classrooms in the moisture-damaged school. Passively collected settled dust and PM collected actively with the NIOSH Sampler (Stage 1) caused a clear response in exposed cells. The results suggested the higher relative immunotoxicological activity of dust from the moisture-damaged school. The NIOSH Sampler is a promising candidate for the collection of size-fractionated PM to be used in toxicity testing. The applicability of such sampling strategy in grading moisture damage severity in buildings needs to be developed further in a larger cohort of buildings. PMID:27569522

  20. 浅析两种组合式空调机喷淋回水过滤箱%Two Kinds of Filter Box of Combined Air Conditioner

    Institute of Scientific and Technical Information of China (English)

    刘晓鹏

    2016-01-01

    The filtering of combined air conditioner seems simple, but the mismanagement will make the nozzle clogging and increase the energy consumption. External spray water filter has many advantages and it can clean the filter net on-line with-out stopping, ensure the nozzle smooth and keep the air conditioner in good condition.%组合式空调机喷淋泵喷淋回水过滤看似简单,但运行管理不善会使喷嘴堵塞,喷淋效果变差,影响热湿交换效果,进而增加空调机运行能耗。通过对比,外置式喷淋回水过滤箱相比内置式有诸多优点,可实现实时在线不停机清洗过滤网,使清洗滤网更加简便,保证喷嘴通畅,使空调机随时处在良好的运行状态。

  1. HEPA filter monitoring program

    Science.gov (United States)

    Kirchner, K. N.; Johnson, C. M.; Aiken, W. F.; Lucerna, J. J.; Barnett, R. L.; Jensen, R. T.

    1986-07-01

    The testing and replacement of HEPA filters, widely used in the nuclear industry to purify process air, are costly and labor-intensive. Current methods of testing filter performance, such as differential pressure measurement and scanning air monitoring, allow determination of overall filter performance but preclude detection of incipient filter failure such as small holes in the filters. Using current technology, a continual in-situ monitoring system was designed which provides three major improvements over current methods of filter testing and replacement. The improvements include: cost savings by reducing the number of intact filters which are currently being replaced unnecessarily; more accurate and quantitative measurement of filter performance; and reduced personnel exposure to a radioactive environment by automatically performing most testing operations.

  2. Study on DOP substitutes for leaking rate testing of HEPA filter used in nuclear air cleaning systems

    International Nuclear Information System (INIS)

    Based on an extensive investigation over available literatures concerning HEPA filter testing, PEG400, SHELL on dina oil 15 and P.a. were chosen as candidates for Dop substitutes, and on which a series of tests were conducted about their aerosol conversion rate, particle size distribution, Dop detector response and leaking rate in H EPA filter. With consideration of technical properties, safety performance and economy, homemade P.a. is finally selected as the best substitute for Dop among the three. (authors)

  3. Unmanned platform for long-range remote analysis of volatile compounds in air samples.

    Science.gov (United States)

    da Costa, Eric T; Neves, Carlos A; Hotta, Guilherme M; Vidal, Denis T R; Barros, Marcelo F; Ayon, Arturo A; Garcia, Carlos D; do Lago, Claudimir Lucio

    2012-09-01

    This paper describes a long-range remotely controlled CE system built on an all-terrain vehicle. A four-stroke engine and a set of 12-V batteries were used to provide power to a series of subsystems that include drivers, communication, computers, and a capillary electrophoresis module. This dedicated instrument allows air sampling using a polypropylene porous tube, coupled to a flow system that transports the sample to the inlet of a fused-silica capillary. A hybrid approach was used for the construction of the analytical subsystem combining a conventional fused-silica capillary (used for separation) and a laser machined microfluidic block, made of PMMA. A solid-state cooling approach was also integrated in the CE module to enable controlling the temperature and therefore increasing the useful range of the robot. Although ultimately intended for detection of chemical warfare agents, the proposed system was used to analyze a series of volatile organic acids. As such, the system allowed the separation and detection of formic, acetic, and propionic acids with signal-to-noise ratios of 414, 150, and 115, respectively, after sampling by only 30 s and performing an electrokinetic injection during 2.0 s at 1.0 kV. PMID:22965708

  4. 24-HOUR DIFFUSIVE SAMPLING OF TOXIC VOCS IN AIR ONTO CARBOPACK X SOLID ADSORBENT FOLLOWED BY THERMAL DESORPTION/GC/MS ANALYSIS - LABORATORY STUDIES

    Science.gov (United States)

    Diffusive sampling of a mixture of 42 volatile organic compounds (VOCs) in humidified, purified air onto the solid adsorbent Carbopack X was evaluated under controlled laboratory conditions. The evaluation included variations in sample air temperature, relative humidity, and ozon...

  5. Assessment of respiratory effect of air pollution: study design on general population samples.

    Science.gov (United States)

    Baldacci, S; Carrozzi, L; Viegi, G; Giuntini, C

    1997-01-01

    The aim of this paper is to describe an epidemiological model to investigate the relationship between respiratory diseases and environmental air pollution. In the Po Delta prospective study, subjects were investigated before and after a large thermoelectric power plant began operating, in 1980 to 1982 and in 1988 to 1991, respectively. The Pisa prospective study was performed in 1986 to 1988 and in 1991 to 1993, before and after the construction of a new expressway that encircles the city from the North to the Southeast. In each survey, subjects completed the interviewer-administered standardized CNR questionnaire on respiratory symptoms/diseases and risk factors, and performed lung function tests. In the second survey of each study, skin prick tests, total serum IgE determination, methacholine challenge test and biomarkers (such as sister chromatide exchanges, micronuclei, chromosomal abnormalities, DNA and hemoglobin adducts) were also performed. Concentrations of total suspended particulate and SO2 in both surveys were higher in urban than in rural areas, as well as symptom/disease prevalences and bronchial reactivity. Subgroups of subjects from the two samples were enrolled to perform a specific study on the acute respiratory effects of indoor pollution; the daily presence of symptoms and measurements of peak expiratory flow (PEF), daily activity pattern, and assessment of the indoor air quality (particulates particulates, especially asthmatics. In conclusion, these studies represent a basis for further analyses to better define the relationship between respiratory health and indoor/outdoor pollutant levels.

  6. Inter-laboratory comparison study on measuring semi-volatile organic chemicals in standards and air samples.

    Science.gov (United States)

    Su, Yushan; Hung, Hayley

    2010-11-01

    Measurements of semi-volatile organic chemicals (SVOCs) were compared among 21 laboratories from 7 countries through the analysis of standards, a blind sample, an air extract, and an atmospheric dust sample. Measurement accuracy strongly depended on analytes, laboratories, and types of standards and samples. Intra-laboratory precision was generally good with relative standard deviations (RSDs) of triplicate injections laboratory variability, measured by RSDs of all measurements, was in the range of 2.8-58% in analyzing standards, and 6.9-190% in analyzing blind sample and air extract. Inter-laboratory precision was poorer when samples were subject to cleanup processes, or when SVOCs were quantified at low concentrations. In general, inter-laboratory differences up to a factor of 2 can be expected to analyze atmospheric SVOCs. When comparing air measurements from different laboratories, caution should be exercised if the data variability is less than the inter-laboratory differences.

  7. Temporal-spatial analysis of U.S.-Mexico border environmental fine and coarse PM air sample extract activity in human bronchial epithelial cells

    International Nuclear Information System (INIS)

    Particulate matter less than 10 μm (PM10) has been shown to be associated with aggravation of asthma and respiratory and cardiopulmonary morbidity. There is also great interest in the potential health effects of PM2.5. Particulate matter (PM) varies in composition both spatially and temporally depending on the source, location and seasonal condition. El Paso County which lies in the Paso del Norte airshed is a unique location to study ambient air pollution due to three major points: the geological land formation, the relatively large population and the various sources of PM. In this study, dichotomous filters were collected from various sites in El Paso County every 7 days for a period of 1 year. The sampling sites were both distant and near border crossings, which are near heavily populated areas with high traffic volume. Fine (PM2.5) and Coarse (PM10-2.5) PM filter samples were extracted using dichloromethane and were assessed for biologic activity and polycyclic aromatic (PAH) content. Three sets of marker genes human BEAS2B bronchial epithelial cells were utilized to assess the effects of airborne PAHs on biologic activities associated with specific biological pathways associated with airway diseases. These pathways included in inflammatory cytokine production (IL-6, IL-8), oxidative stress (HMOX-1, NQO-1, ALDH3A1, AKR1C1), and aryl hydrocarbon receptor (AhR)-dependent signaling (CYP1A1). Results demonstrated interesting temporal and spatial patterns of gene induction for all pathways, particularly those associated with oxidative stress, and significant differences in the PAHs detected in the PM10-2.5 and PM2.5 fractions. Temporally, the greatest effects on gene induction were observed in winter months, which appeared to correlate with inversions that are common in the air basin. Spatially, the greatest gene expression increases were seen in extracts collected from the central most areas of El Paso which are also closest to highways and border crossings.

  8. Sampling of power plant stacks for air toxic emissions: Topical report for Phases 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-21

    Under contract with the US Department of Energy (DE-AC22-92PCO0367), Pittsburgh Energy Technology Center, Radian Corporation has conducted a test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPS). Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical charactization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions.

  9. Molecular beam mass spectrometric sampling of minor species from coal dust-air flames

    International Nuclear Information System (INIS)

    It has been demonstrated that unaugmented, unconfined, premixed coal dust-air flames can be stabilized on small conical or flat, Meeker type burners. Since these flames are laminar, they can be used to study the kinetics of various processes in coal combustion and related areas such as understanding mechanisms of fireside corrosion and of flame and explosive inhibition. Some of the current work with these flames is directed toward identification and measurement of minor alkali metal and other species responsible for fireside corrosion. In order to make these measurements, molecular beam mass spectrometric sampling techniques have been adpated for use with these heterogeneous flames. In this paper, the equipment and techniques used are reviewed and some preliminary results presented

  10. Spectrophotometric determination of nitrogen dioxide in air and nitrite in water and soil samples

    Energy Technology Data Exchange (ETDEWEB)

    Pandurangappa, M.; Balasubramanian, N. [Indian Institute of Technology, Madras (India)

    1995-02-01

    A sensitive spectrophotometric method for the determination of nitrogen dioxide in air and nitrite in water and soil samples is described. Nitrogen dioxide in air is fixed as nitrite ion in alkaline sodium arsenite or in triethanolamine absorber solutions. The method is based on the diazo coupling reaction between p-nitro aniline and 1-hydroxy-2-naphthoic acid. The azo dye formed under aqueous condition has an absorption maximum at 585nm and obeys Beer`s law over the range 0-25{mu}g of nitrite. The colour system is stable for 72h. The relative standard deviation is 2.7% for ten determinations at 15{mu}g of nitrite. The dye is extracted with 1:1 isoamyl alcohol-IBMK mixture and stabilisation with methanolic potassium hydroxide showed {lambda}{sub max} at 610nm. It obeys Beer`s law over the range 0-4{mu}g of nitrite. The colour system is stable for 40h in organic phase and the relative standard deviation is 2.5% for ten determinations at 3{mu}g of nitrite. The molar absorptivity of the colour system is 3.68 x 10{sup 4} Lmol{sup {minus}1} cm{sup {minus}1}. The effect of interfering gases and other ions on the determination of nitrite is described. The developed method has been applied for the determination of residual nitrogen dioxide gas present in the laboratory fume cupboard and automobile exhaust gases. In addition, the method has been applied for the determination of nitrite and nitrate in samples like water, soil and radiator coolants.

  11. GUIDE TO CALCULATING TRANSPORT EFFICIENCY OF AEROSOLS IN OCCUPATIONAL AIR SAMPLING SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Hogue, M.; Hadlock, D.; Thompson, M.; Farfan, E.

    2013-11-12

    This report will present hand calculations for transport efficiency based on aspiration efficiency and particle deposition losses. Because the hand calculations become long and tedious, especially for lognormal distributions of aerosols, an R script (R 2011) will be provided for each element examined. Calculations are provided for the most common elements in a remote air sampling system, including a thin-walled probe in ambient air, straight tubing, bends and a sample housing. One popular alternative approach would be to put such calculations in a spreadsheet, a thorough version of which is shared by Paul Baron via the Aerocalc spreadsheet (Baron 2012). To provide greater transparency and to avoid common spreadsheet vulnerabilities to errors (Burns 2012), this report uses R. The particle size is based on the concept of activity median aerodynamic diameter (AMAD). The AMAD is a particle size in an aerosol where fifty percent of the activity in the aerosol is associated with particles of aerodynamic diameter greater than the AMAD. This concept allows for the simplification of transport efficiency calculations where all particles are treated as spheres with the density of water (1g cm-3). In reality, particle densities depend on the actual material involved. Particle geometries can be very complicated. Dynamic shape factors are provided by Hinds (Hinds 1999). Some example factors are: 1.00 for a sphere, 1.08 for a cube, 1.68 for a long cylinder (10 times as long as it is wide), 1.05 to 1.11 for bituminous coal, 1.57 for sand and 1.88 for talc. Revision 1 is made to correct an error in the original version of this report. The particle distributions are based on activity weighting of particles rather than based on the number of particles of each size. Therefore, the mass correction made in the original version is removed from the text and the calculations. Results affected by the change are updated.

  12. Bionics: prcise color tuning by interference in nature and technology-applications in surface-micromachined 1.55μm vertical air-cavity filters

    Science.gov (United States)

    Hillmer, Hartmut; Daleiden, Juergen; Prott, Cornelia; Irmer, Soeren; Roemer, Friedhard; Ataro, Edwin; Tarraf, Amer; Ruehling, H.; Maniak, Markus; Strassner, Martin

    2003-01-01

    Bionics transfers the principles of success of nature into natural science, engineering disciplines and applications. Often generation and detection of different spectral colors play key roles in communication in both, nature and technology. The latter one refers e.g. to dense wavelength division multiplex optical communication systems. This paper shows interesting parallels in tunable spectral light filtering by butterfly wings and by tunable optical filters used in optical communication systems. In both cases light interferes constructively and destructively with nano- and microstructures of appropriate shape, dimensions and materials. In this paper methodology is strongly emphasized. We demonstrate that tailored scaling allows the effectiveness of physical effects to be enhanced in nature and technology. These principles are rigorously applied in micromachined 1.55μm vertical-resonator-based filters, capable of wide, continuous, monotonic and kink-free tuning by a single control parameter. Tuning is achieved by mechanically actuating one or several membranes embedded by air-gaps in a vertical resonator including two ultra-highly reflective DBR mirrors. The layers of mirrors reveal a very strong refractive index contrast. Filters including InP/air-gap DBR's (3.5 periods) using GaInAs sacrificial layers reveal a continuous tuning of >9% of the absolute wavelength. Varying a reverse voltage (U=0 .. -3.2V) between the membranes, a tuning range up to 142nm was obtained due to electrostatic actuation. Appropriate miniaturization is shown to increase the mechanical stability and the effectiveness of spectral tuning by electrostatic actuation since the relative significance of the fundamental physical forces can be shifted considerably by appropriate scaling.

  13. The decrease of the energy performance for the soiling of the air filters in gas turbines; Disminucion de la eficiencia energetica por ensuciamiento de filtros de aire en turbinas de gas

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, H.; Ambriz, J. J.; Vargas, M.; Godinez, M.; Gomez, F.; Valdez, L.; Pantoja, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Mexico D. F. (Mexico)

    1995-12-31

    The object of this paper is to study the effect in the turbine output of a gas turbine of the conditions of the compressor air inlet in going through a series of filters. The algorithm for the calculation of the energy losses due to the variation of the pressure drop caused by the filters according to their cleanliness condition. In the first part the series of variables that affect the gas turbines performance are exemplified, afterwards the characteristics of the air flow into a turbine are presented as well as their effects on the system. Later on, the results obtained of the system simulation are presented and compared with a real case. From the results it can be determined, that depending on the system and on the environment conditions the efficiency drop might be up to 3%, in accordance with the filters cleanliness. The maintenance periods strongly depend on the air quality variations at the filter house inlet in the zone where the power plant is located. [Espanol] El presente trabajo tiene por objetivo estudiar el efecto en la potencia generada en una turbina de gas de las condiciones de entrada del aire al compresor de una turbina de gas al pasar por un conjunto de filtros. Se presenta el algoritmo para la determinacion de las perdidas energeticas debidas a la variacion de la caida de presion generada por los filtros de acuerdo con su estado de limpieza. En la primera parte se ejemplifica el conjunto de variables que influyen en la eficiencia de las turbinas de gas, posteriormente se mencionan las caracteristicas de flujo de aire hacia una turbina y se muestran los efectos sobre el sistema. A continuacion se presentan los resultados obtenidos de la simulacion del sistema y se comparan con un caso real. De los resultados se puede apreciar que, dependiendo del sistema y de las condiciones ambientales el decremento en la eficiencia puede ser hasta del 3% en funcion del nivel de limpieza de los filtros. Los periodos de mantenimiento dependen fuertemente de las

  14. 5. Sampling

    International Nuclear Information System (INIS)

    The sampling is described for radionuclide X-ray fluorescence analysis. Aerosols are captured with various filter materials whose properties are summed up in the table. Fine dispersed solid and liquid particles and gaseous admixtures may be captured by bubbling air through a suitable absorption solution. The concentration of small amounts of impurities from large volumes of air is done by adsorbing impurities on surfactants, e.g., activated charcoal, silica gel, etc. Aerosols may be captured using an electrostatic precipitator and aerosol fractions may be separated with a cascade impactor. Water sampling differs by the water source, i.e., ground water, surface water, rain or waste water. Soil samples are taken by probes. (ES)

  15. A filter paper-based microdevice for low-cost, rapid, and automated DNA extraction and amplification from diverse sample types.

    Science.gov (United States)

    Gan, Wupeng; Zhuang, Bin; Zhang, Pengfei; Han, Junping; Li, Cai-Xia; Liu, Peng

    2014-10-01

    A plastic microfluidic device that integrates a filter disc as a DNA capture phase was successfully developed for low-cost, rapid and automated DNA extraction and PCR amplification from various raw samples. The microdevice was constructed by sandwiching a piece of Fusion 5 filter, as well as a PDMS (polydimethylsiloxane) membrane, between two PMMA (poly(methyl methacrylate)) layers. An automated DNA extraction from 1 μL of human whole blood can be finished on the chip in 7 minutes by sequentially aspirating NaOH, HCl, and water through the filter. The filter disc containing extracted DNA was then taken out directly for PCR. On-chip DNA purification from 0.25-1 μL of human whole blood yielded 8.1-21.8 ng of DNA, higher than those obtained using QIAamp® DNA Micro kits. To realize DNA extraction from raw samples, an additional sample loading chamber containing a filter net with an 80 μm mesh size was designed in front of the extraction chamber to accommodate sample materials. Real-world samples, including whole blood, dried blood stains on Whatman® 903 paper, dried blood stains on FTA™ cards, buccal swabs, saliva, and cigarette butts, can all be processed in the system in 8 minutes. In addition, multiplex amplification of 15 STR (short tandem repeat) loci and Sanger-based DNA sequencing of the 520 bp GJB2 gene were accomplished from the filters that contained extracted DNA from blood. To further prove the feasibility of integrating this extraction method with downstream analyses, "in situ" PCR amplifications were successfully performed in the DNA extraction chamber following DNA purification from blood and blood stains without DNA elution. Using a modified protocol to bond the PDMS and PMMA, our plastic PDMS devices withstood the PCR process without any leakage. This study represents a significant step towards the practical application of on-chip DNA extraction methods, as well as the development of fully integrated genetic analytical systems.

  16. The use of nylon and glass fiber filter separators with different pore sizes in air-cathode single-chamber microbial fuel cells

    KAUST Repository

    Zhang, Xiaoyuan

    2010-01-01

    Separators are needed in microbial fuel cells (MFCs) to reduce electrode spacing and preventing electrode short circuiting. The use of nylon and glass fiber filter separators in single-chamber, air-cathode MFCs was examined for their effect on performance. Larger pore nylon mesh were used that had regular mesh weaves with pores ranging from 10 to 160 μm, while smaller pore-size nylon filters (0.2-0.45 μm) and glass fiber filters (0.7-2.0 μm) had a more random structure. The pore size of both types of nylon filters had a direct and predictable effect on power production, with power increasing from 443 ± 27 to 650 ± 7 mW m-2 for pore sizes of 0.2 and 0.45 μm, and from 769 ± 65 to 941 ± 47 mW m-2 for 10 to 160 μm. In contrast, changes in pore sizes of the glass fiber filters resulted in a relatively narrow change in power (732 ± 48 to 779 ± 43 mW m-2) for pore sizes of 0.7 to 2 μm. An ideal separator should increase both power density and Coulombic efficiency (CE). However, CEs measured for the different separators were inversely correlated with power production, demonstrating that materials which reduced the oxygen diffusion into the reactor also hindered proton transport to the cathode, reducing power production through increased internal resistance. Our results highlight the need to develop separators that control oxygen transfer and facilitate proton transfer to the cathode. © 2010 The Royal Society of Chemistry.

  17. Estimating surface CO2 fluxes from space-borne CO2 dry air mole fraction observations using an ensemble Kalman Filter

    Directory of Open Access Journals (Sweden)

    S. Dance

    2009-04-01

    Full Text Available We have developed an ensemble Kalman Filter (EnKF to estimate 8-day regional surface fluxes of CO2 from space-borne CO2 dry-air mole fraction observations (XCO2 and evaluate the approach using a series of synthetic experiments, in preparation for data from the NASA Orbiting Carbon Observatory (OCO. The 32-day duty cycle of OCO alternates every 16 days between nadir and glint measurements of backscattered solar radiation at short-wave infrared wavelengths. The EnKF uses an ensemble of states to represent the error covariances to estimate 8-day CO2 surface fluxes over 144 geographical regions. We use a 12×8-day lag window, recognising that XCO2 measurements include surface flux information from prior time windows. The observation operator that relates surface CO2 fluxes to atmospheric distributions of XCO2 includes: a the GEOS-Chem transport model that relates surface fluxes to global 3-D distributions of CO2 concentrations, which are sampled at the time and location of OCO measurements that are cloud-free and have aerosol optical depths 2 profiles to XCO2, accounting for differences between nadir and glint measurements, and the associated scene-dependent observation errors. We show that OCO XCO2 measurements significantly reduce the uncertainties of surface CO2 flux estimates. Glint measurements are generally better at constraining ocean CO2 flux estimates. Nadir XCO2 measurements over the terrestrial tropics are sparse throughout the year because of either clouds or smoke. Glint measurements provide the most effective constraint for estimating tropical terrestrial CO2 fluxes by accurately sampling fresh continental outflow over neighbouring oceans. We also present results from sensitivity experiments that investigate how flux estimates change with 1 bias and unbiased errors, 2 alternative duty cycles, 3 measurement density and correlations, 4 the spatial resolution of estimated flux estimates, and 5 reducing the length of the lag window and the

  18. Evaluation of Rn equilibrium factor using charcoal filter

    International Nuclear Information System (INIS)

    A simple and new evaluation system for radon equilibrium factor has been developed. Radon equilibrium factor is defined as a ratio between radon progeny concentration and radon concentration in air. Radon progeny in air becomes one of the main factors of public dose. However radon concentration itself in air has usually been estimated, because its detection is much easier than that of its progeny. In this dosimetry technique, radon equilibrium becomes the most important parameter we must adequately evaluate in advance. In this study, a new system using a charcoal filter for evaluation of radon equilibrium factor using charcoal filter was discussed. Two filters are combined to sample the airborne radioactivity of radon family. One of them is the charcoal filter, where is the main point of this study. Radon concentration is estimated based on the radioactivity sampled on a charcoal filter, and radon progeny concentration is based on the radioactivity on a glass-fiber filter. We have already fully known the characteristics of the glass-fiber filter for radon progeny. Therefore we tested charcoal filters here and obtained some characteristics on its sampling ability for radon. Especially we focused on the variety of sample abilities based on sampling flow-rate (L/min) and sampling duration (min). As a result, the most optimum sampling flow-rate was determined as 20 L/min and sampling duration was 10 min, based on the results gained by several experiments. According to this new evaluation system, we can calculate more adequate radon equilibrium factor easily because both concentrations of radon and its progeny in a same sample air can be determined at the same time. We can well adopt this system in special environments like in mines and undergrounds. (author)

  19. Effects of hydraulic retention time and nitrobenzene concentration on the performance of sequential upflow anaerobic filter and air lift reactors in treating nitrobenzene-containing wastewater

    DEFF Research Database (Denmark)

    Wu, Jinhua; Chen, Guocai; Gu, Jingjing;

    2014-01-01

    Sequential upflow anaerobic filter (UAF)/air lift (ALR) reactors were employed to investigate the effects of hydraulic retention time (HRT) and nitrobenzene (NB) concentration on treatment of NB-containing wastewater. The results showed that NB was effectively reduced to aniline (AN) with glucose...... and the influent NB concentration increased from 400 to 800 mg l super(-1), respectively. The results showed that sequential UAF/ALR system can be operated at low HRTs and high NB concentrations without significantly affecting the removal efficiency of NB in the reactor system. The UAF/ALR system can provide...... an effective yet low cost method for treatment of NB-containing industrial wastewater....

  20. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: BAGHOUSE FILTRATION PRODUCTS, BWF AMERICA, INC., GRADE 700 MPS POLYESTER FELT FILTER SAMPLE

    Science.gov (United States)

    EPA's National Risk Management Research Laboratory, through its Environmental Technology Verification Program, evaluated the performance of a bag house filtration product for use controlling PM2.5. The product was BWF America, Inc., filter fabric Grade 700 Polyester Felt. All tes...

  1. Sampling of power plant stacks for air toxic emissions: Final report for Phases 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-28

    A test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPs) was conducted . Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical characterization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions. Field testing was conducted in two phases. The Phase I field program was performed over the period of August 24 through September 20, 1992, at the Tennessee Valley Authority Widows Creek Unit 8 Power Station, located near Stevenson (Jackson County), Alabama, on the Tennessee River. Sampling activities for Phase II were conducted from September 11 through October 14, 1993. Widows Creek Unit 8 is a 575-megawatt plant that uses bituminous coal averaging 3.7% sulfur and 13% ash. Downstream of the boiler, a venture wet scrubbing system is used for control of both sulfur dioxide and particulate emissions. There is no electrostatic precipitator (ESP) in this system. This system is atypical and represents only about 5% of the US utility industry. However, this site was chosen for this study because of the lack of information available for this particulate emission control system.

  2. Uncertainties in Air Exchange using Continuous-Injection, Long-Term Sampling Tracer-Gas Methods

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max H.; Walker, Iain S.; Lunden, Melissa M.

    2013-12-01

    The PerFluorocarbon Tracer (PFT) method is a low-cost approach commonly used for measuring air exchange in buildings using tracer gases. It is a specific application of the more general Continuous-Injection, Long-Term Sampling (CILTS) method. The technique is widely used but there has been little work on understanding the uncertainties (both precision and bias) associated with its use, particularly given that it is typically deployed by untrained or lightly trained people to minimize experimental costs. In this article we will conduct a first-principles error analysis to estimate the uncertainties and then compare that analysis to CILTS measurements that were over-sampled, through the use of multiple tracers and emitter and sampler distribution patterns, in three houses. We find that the CILTS method can have an overall uncertainty of 10-15percent in ideal circumstances, but that even in highly controlled field experiments done by trained experimenters expected uncertainties are about 20percent. In addition, there are many field conditions (such as open windows) where CILTS is not likely to provide any quantitative data. Even avoiding the worst situations of assumption violations CILTS should be considered as having a something like a ?factor of two? uncertainty for the broad field trials that it is typically used in. We provide guidance on how to deploy CILTS and design the experiment to minimize uncertainties.

  3. Genotoxicity, inflammation and physico-chemical properties of fine particle samples from an incineration energy plant and urban air

    DEFF Research Database (Denmark)

    Sharma, Anoop Kumar; Jensen, Keld Alstrup; Rank, Jette;

    2007-01-01

    . The samples were extracted and examined for mutagenicity in Salmonella typhimurium strains TA98, YG1041 and YG5161, for content of inorganic elements and for the presence of eight polycyclic aromatic hydrocarbons. The induction of IL-6 and IL-8 mRNA expression and the presence of DNA damage - tested...... from all four sites caused similar levels of DNA damage in A549 cells; only the oven hall samples gave results that were statistically significantly different from those obtained with street-air samples. The receiving hall and the urban air samples were similarly inflammatory (relative IL-8 m...... principal component. Several clusters of constituents were identified. One cluster consisted of all the polycyclic aromatic hydrocarbons (PAH), several groups of metals and one group of the biological endpoints (DNA damage, IL-6 and IL-8 mRNA expression). The PAH and the inorganic content of the air...

  4. Design of complex-valued variable FIR digital filters and its application to the realization of arbitrary sampling rate conversion for complex signals

    OpenAIRE

    Tsui, KM; Chan, SC; Tse, KW

    2005-01-01

    This brief studies the design of complex-valued variable digital filters (CVDFs) and their applications to the efficient arbitrary sample rate conversion for complex signals. The design of CVDFs using either the minimax or least-squares criteria is formulated as a convex optimization problem and solved using the second-order cone programming (SOCP). In addition, linear and convex quadratic inequality constraints can be readily incorporated. Design examples are given to demonstrate the effecti...

  5. Indoor Air Quality in Selected Samples of Primary Schools in Kuala Terengganu, Malaysia

    OpenAIRE

    Marzuki Ismail

    2010-01-01

    Studies have found out that indoor air quality affects human especially children and the elderly more compared to ambient atmospheric air. This study aims to investigate indoor air pollutants concentration in selected vernacular schools with different surrounding human activities in Kuala Terengganu, the administrative and commercial center of Terengganu state. Failure to identify and establish indoor air pollution status can increase the chance of long-term and short-term health problems for...

  6. Cryogenic separation of oxygen-argon mixture in natural air samples for isotopic and molecular ratios

    Science.gov (United States)

    Habeeb Rahman, Keedakkadan; Abe, Osamu

    2014-05-01

    The discovery of mass independent isotope fractionation in oxygen during the formation of ozone in the stratosphere has initiated a wide application in isotope geochemistry field. Separation of oxygen-argon mixture has become the foundation of high precision analysis of Δ17O and δ(O2/Ar) for geochemical applications. Here we present precise and simplified cryogenic separation of argon oxygen mixture from the atmospheric and dissolved air using 30/60 mesh 5A molecular sieve zeolite. A pioneer study of this method was conducted by Thiemens and Meagher in 1984. The column which is made of glass tube contains about 1.1 grams of molecular sieve zeolite and both ends of column was filled with glass wools. The experimental set up was tested for different combination of molecular sieves and slurry temperatures. We found the most efficient condition for the separation was at a column temperature of -103°C. For complete transfer of O2 and Ar mixture usually takes in 15-20 minutes time. The isotopic ratios of oxygen were analyzed using mass spectrometer (Thermo Fischer Delta Plus) relative to reference oxygen-argon mixture at 3V of m/z 32 for both sample and reference side. The signals of m/z 28, 32, and 40 were measured by dynamically to determine oxygen -argon ratio and to check nitrogen contamination. Repeated measurements of atmospheric air yielded a reproducibility (SE n=80) of 0.006, 0.004 and 0.19‰ for δ17O, δ18O and δO2/Ar respectively. The isotopic and molecular fractionation of argon- oxygen mixture during gas adsorption and desorption while using molecular sieve under liquid nitrogen temperature was studied. We have established a linear relationship governing the effect of 13X and 5A molecular sieves on molecular fractionation. And suggested the use of single 1/8" pellet 13X molecular sieve provided a negligible fractionation.

  7. Occurrence and quantitative microbial risk assessment of Cryptosporidium and Giardia in soil and air samples

    Directory of Open Access Journals (Sweden)

    Ana Paola Balderrama-Carmona

    2014-09-01

    Conclusions: Soil and air inhalation and/or ingestion are important vehicles for these parasites. To our knowledge, the results obtained in the present study represent the first QMRAs for cryptosporidiosis and giardiasis due to soil and air inhalation/ingestion in Mexico. In addition, this is the first evidence of the microbial air quality around these parasites in rural zones.

  8. Evaluation of Trapper-Collected Nobuto Filter-Paper Blood Samples for Distemper and Parvovirus Antibody Detection in Coyotes (Canis latrans) and Raccoons (Procyon lotor).

    Science.gov (United States)

    Kamps, Amanda J; Dubay, Shelli A; Langenberg, Julie; Maes, Roger K

    2015-07-01

    Blood samples are often collected from free-ranging wildlife for antibody detection. However, filter-paper (FP) strips are more cost efficient and easy to collect and store. We evaluated trapper-collected FP strips and body-cavity blood for canine distemper (CDV) and parvovirus (CPV-2) antibody detection in raccoons (Procyon lotor) and coyotes (Canis latrans). From 2008 to 2010, licensed trappers near Madison and Milwaukee, Wisconsin, US collected paired samples from harvested animals. Canine distemper antibodies were detected using virus neutralization and parvovirus antibodies were detected using hemagglutination inhibition. Titers ≥ 1:32 for CDV and ≥ 1:25 for CPV-2 were considered evidence of exposure. Using Cohen's kappa test of agreement, FP strip titers agreed with sera for CDV in coyotes (n = 28, K = 0.772) and raccoons (n = 29, K = 0.858) and for CPV-2 in coyotes (n = 40, K = 0.775) and raccoons (n = 70, K = 0.646). However, raccoons determined to be exposed to CPV-2 from sera were unexposed by FP strips in 35% of the samples. Titer results may be affected by quality and volume of blood samples, interval between collection and processing, small sample sizes, and diagnostic testing procedures. Filter-paper strips can be useful for detecting CDV and CPV-2 exposure in coyotes and raccoons with correct field sample collection and appropriate diagnostic testing procedures. PMID:25973631

  9. Seroepidemiological study of human cysticercosis with blood samples collected on filter paper, in Lages, State of Santa Catarina, Brazil, 2004-2005

    Directory of Open Access Journals (Sweden)

    Maria Márcia Imenes Ishida

    2011-06-01

    Full Text Available INTRODUCTION: Human serofrequency of antibodies against Taenia solium antigens was determined and risk factors for cysticercosis transmission were identified. METHODS: Individuals (n=878 from periurban and rural locations of Lages, SC, were interviewed to gather demographic, sanitary and health information. Interviews and blood sample collections by finger prick on Whatman filter paper were performed from August 2004 to May 2005. Observation determined that 850 samples were suitable for analysis and were tested by ELISA using vesicular fluid of Taenia crassiceps heterologous antigen. To ensure the reliability of the results, 77 samples of the dried blood were matched with sera. The reactive samples were submitted to a serum confirmatory immunoblot (IB test using purified Taenia crassiceps glycoproteins. RESULTS: The ELISA results for the dried blood and serum samples were statistically consistent. ELISA was positive in 186 (21.9% out of 850 individuals. A group of 213 individuals were asked to collect vein blood for IB (186 with positive result in ELISA and 27 with inappropriate whole blood samples and 130 attended the request. The IB was positive in 29 (3.4% out of 850 individuals. A significant correlation (p = 0.0364 was determined among individuals who tested positive in the IB assay who practiced both pig rearing and kitchen gardening. CONCLUSIONS: ELISA with dried blood eluted from filter paper was suitable for cysticercosis population surveys. In Lages, human infection was associated with pig rearing and kitchen gardening. The prevalence index was compatible with other Latin American endemic areas.

  10. Utilizing the partitioning properties of silicone for the passive sampling of polychlorinated biphenyls (PCBs) in indoor air.

    Science.gov (United States)

    Vorkamp, Katrin; Odsbjerg, Lisbeth; Langeland, Majbrith; Mayer, Philipp

    2016-10-01

    The former use of polychlorinated biphenyls (PCBs) in construction materials can lead to elevated indoor air concentrations. We studied the partitioning of PCB congeners between indoor air and silicone with a view to establish passive sampling of PCBs. The release of PCB congeners from silicone followed first order kinetics and confirmed air-side rate-limited mass transfer. Logarithmic elimination rate constants decreased linearly with the logKOA values of the PCB congeners, but varied in a non-linear way with air velocity. Linear uptake of PCBs was found for silicone disks (0.5 mm thickness) in a petri dish, while PCBs reached equilibrium in silicone-coated paper sheets (0.001 mm silicone on each side) exposed to indoor air for 1-2 weeks. The ratios of equilibrium concentrations in silicone and conventionally measured air concentrations were roughly comparable with silicone-air partition coefficients, but further research is required for the determination of silicone-air partition coefficients. Avoiding performance reference compounds (PRCs) because of the indoor setting, the two formats were calibrated against conventional active measurements. Comparisons of air concentrations derived from active and kinetic passive sampling showed a divergence by factors of 2.4 and 2.0 (median values) for the petri dishes and the silicone-coated paper, respectively. With promising results for sensitivity and precision, the calibration of kinetic passive samplers remains the main challenge and will need suitable, non-hazardous PRCs. Equilibrium sampling indicated promising alternatives. PMID:27389945

  11. Air filtration in HVAC systems

    CERN Document Server

    Ginestet, Alain; Tronville, Paolo; Hyttinen, Marko

    2010-01-01

    Air filtration Guidebook will help the designer and user to understand the background and criteria for air filtration, how to select air filters and avoid problems associated with hygienic and other conditions at operation of air filters. The selection of air filters is based on external conditions such as levels of existing pollutants, indoor air quality and energy efficiency requirements.

  12. Aircraft Cabin Air Sampling Study; Part 2 of the Final Report

    OpenAIRE

    Crump, Derrick; Harrison, Paul; Walton, Christopher

    2011-01-01

    This is the second part of the report on aircraft cabin air quality prepared by Cranfield University for the Department for Transport. The study was set up in light of concerns about possible adverse impacts on the health and well-being of air crew resulting from exposure to substances in cabin air. Part 1 of the report describes in detail the methodology used in the study, summarises the results obtained and assesses cabin air quality against available exposure limits and the quality of air ...

  13. High resolution alpha-particle-spectrometry for radium analysis -the effects of sample thickness and filter pore size

    International Nuclear Information System (INIS)

    In the α-particle spectrometric technique for radium isotope analysis, the effects of the barium carrier thickness and pore size of the membrane filter (used for the main Ba-Ra sulphate filtration) on the resolution of the α-particle energy peaks were investigated. With 0.45 μm Millipore membrane filters, the full width at half maximum (FWHM) for 4.78 MeV α-decay peak of 226Ra decreased from 221.7 to 121.3 keV with reduction in barium carrier additions from 320 to 20 μg Ba. The resolution further improved to 67.0 keV for 20 μg Ba carrier when 0.2 μm Nucleopore filters were used. There was also a significant decrease (20-50%) in the retention of radon and its daughters compared to their equilibrium concentrations as the barium carrier thickness was reduced. A correlation study between 133Ba tracer and 226Ra isotopes recovery factors gave a recovery factor 226Ra/133Ba ratio of 0.93 ± 0.08 in the main Ba-Ra sulphate precipitate under various pH and sulphate concentration conditions. (author)

  14. Day and night variation in chemical composition and toxicological responses of size segregated urban air PM samples in a high air pollution situation

    Science.gov (United States)

    Jalava, P. I.; Wang, Q.; Kuuspalo, K.; Ruusunen, J.; Hao, L.; Fang, D.; Väisänen, O.; Ruuskanen, A.; Sippula, O.; Happo, M. S.; Uski, O.; Kasurinen, S.; Torvela, T.; Koponen, H.; Lehtinen, K. E. J.; Komppula, M.; Gu, C.; Jokiniemi, J.; Hirvonen, M.-R.

    2015-11-01

    Urban air particulate pollution is a known cause for adverse human health effects worldwide. China has encountered air quality problems in recent years due to rapid industrialization. Toxicological effects induced by particulate air pollution vary with particle sizes and season. However, it is not known how distinctively different photochemical activity and different emission sources during the day and the night affect the chemical composition of the PM size ranges and subsequently how it is reflected to the toxicological properties of the PM exposures. The particulate matter (PM) samples were collected in four different size ranges (PM10-2.5; PM2.5-1; PM1-0.2 and PM0.2) with a high volume cascade impactor. The PM samples were extracted with methanol, dried and thereafter used in the chemical and toxicological analyses. RAW264.7 macrophages were exposed to the particulate samples in four different doses for 24 h. Cytotoxicity, inflammatory parameters, cell cycle and genotoxicity were measured after exposure of the cells to particulate samples. Particles were characterized for their chemical composition, including ions, element and PAH compounds, and transmission electron microscopy (TEM) was used to take images of the PM samples. Chemical composition and the induced toxicological responses of the size segregated PM samples showed considerable size dependent differences as well as day to night variation. The PM10-2.5 and the PM0.2 samples had the highest inflammatory potency among the size ranges. Instead, almost all the PM samples were equally cytotoxic and only minor differences were seen in genotoxicity and cell cycle effects. Overall, the PM0.2 samples had the highest toxic potential among the different size ranges in many parameters. PAH compounds in the samples and were generally more abundant during the night than the day, indicating possible photo-oxidation of the PAH compounds due to solar radiation. This was reflected to different toxicity in the PM

  15. Novel process of bio-chemical ammonia removal from air streams using a water reflux system and zeolite as filter media.

    Science.gov (United States)

    Vitzthum von Eckstaedt, Sebastian; Charles, Wipa; Ho, Goen; Cord-Ruwisch, Ralf

    2016-02-01

    A novel biofilter that removes ammonia from air streams and converts it to nitrogen gas has been developed and operated continuously for 300 days. The ammonia from the incoming up-flow air stream is first absorbed into water and the carrier material, zeolite. A continuous gravity reflux of condensed water from the exit of the biofilter provides moisture for nitrifying bacteria to develop and convert dissolved ammonia (ammonium) to nitrite/nitrate. The down-flow of the condensed water reflux washes down nitrite/nitrate preventing ammonium and nitrite/nitrate accumulation at the top region of the biofilter. The evaporation caused by the inflow air leads to the accumulation of nitrite to extremely high concentrations in the bottom of the biofilter. The high nitrite concentrations favour the spontaneous chemical oxidation of ammonium by nitrite to nitrogen (N2). Tests showed that this chemical reaction was catalysed by the zeolite filter medium and allowed it to take place at room temperature. This study shows that ammonia can be removed from air streams and converted to N2 in a fully aerated single step biofilter. The process also overcomes the problem of microorganism-inhibition and resulted in zero leachate production.

  16. Novel process of bio-chemical ammonia removal from air streams using a water reflux system and zeolite as filter media.

    Science.gov (United States)

    Vitzthum von Eckstaedt, Sebastian; Charles, Wipa; Ho, Goen; Cord-Ruwisch, Ralf

    2016-02-01

    A novel biofilter that removes ammonia from air streams and converts it to nitrogen gas has been developed and operated continuously for 300 days. The ammonia from the incoming up-flow air stream is first absorbed into water and the carrier material, zeolite. A continuous gravity reflux of condensed water from the exit of the biofilter provides moisture for nitrifying bacteria to develop and convert dissolved ammonia (ammonium) to nitrite/nitrate. The down-flow of the condensed water reflux washes down nitrite/nitrate preventing ammonium and nitrite/nitrate accumulation at the top region of the biofilter. The evaporation caused by the inflow air leads to the accumulation of nitrite to extremely high concentrations in the bottom of the biofilter. The high nitrite concentrations favour the spontaneous chemical oxidation of ammonium by nitrite to nitrogen (N2). Tests showed that this chemical reaction was catalysed by the zeolite filter medium and allowed it to take place at room temperature. This study shows that ammonia can be removed from air streams and converted to N2 in a fully aerated single step biofilter. The process also overcomes the problem of microorganism-inhibition and resulted in zero leachate production. PMID:26363328

  17. Detection of Campylobacter Bacteria in Air Samples for Continuous Real-Time Monitoring of Campylobacter Colonization in Broiler Flocks

    DEFF Research Database (Denmark)

    Olsen, Katja Nyholm; Lund, Marianne; Skov, J.;

    2009-01-01

    Improved monitoring tools are important for the control of Campylobacter bacteria in broiler production. In this study, we compare the sensitivities of detection of Campylobacter by PCR with feces, dust, and air samples during the lifetimes of broilers in two poultry houses and conclude...... that the sensitivity of detection of Campylobacter in air is comparable to that in other sample materials. Profiling of airborne particles in six poultry houses revealed that the aerodynamic conditions were dependent on the age of the chickens and very comparable among different poultry houses, with low proportions...... of particles in the 0.5- to 2-mu m-diameter range and high proportions in the 2- to 5-mu m-diameter range. Campylobacter could also be detected by PCR in air samples collected at the hanging stage during the slaughter process but not at the other stages tested at the slaughterhouse. The exploitation...

  18. Semi-continuous sampling of health relevant atmospheric particle subfractions for chemical speciation using a rotating drum impactor in series with sequential filter sampler.

    Science.gov (United States)

    Li, Fengxia; Schnelle-Kreis, Jürgen; Karg, Erwin; Cyrys, Josef; Gu, Jianwei; Orasche, Jürgen; Abbaszade, Gülcin; Peters, Annette; Zimmermann, Ralf

    2016-04-01

    To achieve unattended continuous long-term (eg., 1 week) sampling of size-segregated 24-h ambient particulate matter (PM), a sampling strategy of a modified 3-stage rotating drum impactor (RDI) in series with a sequential filter sampler was introduced and verified in a field campaign. Before the field sampling, lab experiment was conducted to test the collection efficiency of the third stage of the RDI using the quartz-fiber filter (QFF) as the substrate. The measured value is 0.36 μm, which is larger than the nominal value 0.1 μm. A fast direct analysis of organic species in all size fractions (levoglucosan were quantified. The comparability of two such sampler sets was verified with respect to the PM collection profile of the two RDIs as well as measured concentration of chemical compounds in each sampled size fraction, so that a future epidemiological study on the relationship between the finest PM/its chemical composition and health outcome could be carried out through parallel sampling at two sites. The internal correlations between the size-segregated organic compounds are discussed. Besides, the correlations between the size-segregated organic species and size-segregated particulate number concentration (PNC) as well as meteorological parameter are discussed as well. PMID:26676546

  19. A novel Whole Air Sample Profiler (WASP for the quantification of volatile organic compounds in the boundary layer

    Directory of Open Access Journals (Sweden)

    J. E. Mak

    2013-05-01

    Full Text Available The emission and fate of reactive VOCs is of inherent interest to those studying chemical biosphere-atmosphere interactions. In-canopy VOC observations are obtainable using tower-based samplers, but the lack of suitable sampling systems for the full boundary layer has limited the data characterizing the vertical structure of such gases above the canopy height and still in the boundary layer. This is the important region where many reactive VOCs are oxidized or otherwise removed. Here we describe an airborne sampling system designed to collect a vertical profile of air into a 3/8" OD tube 150 m in length. The inlet ram air pressure is used to flow sampled air through the tube, which results in a varying flow rate based on aircraft speed and altitude. Since aircraft velocity decreases during ascent, it is necessary to account for the variable flow rate into the tube. This is accomplished using a reference gas that is pulsed into the air stream so that the precise altitude of the collected air can be reconstructed post-collection. The pulsed injections are also used to determine any significant effect from diffusion/mixing within the sampling tube, either during collection or subsequent extraction for gas analysis. This system has been successfully deployed, and we show some measured vertical profiles of isoprene and its oxidation products methacrolein and methyl vinyl ketone from a mixed canopy near Columbia, Missouri.

  20. A novel Whole Air Sample Profiler (WASP for the quantification of volatile organic compounds in the boundary layer

    Directory of Open Access Journals (Sweden)

    J. E. Mak

    2013-10-01

    Full Text Available The emission and fate of reactive volatile organic compounds (VOCs is of inherent interest to those studying chemical biosphere–atmosphere interactions. In-canopy VOC observations are obtainable using tower-based samplers, but the lack of suitable sampling systems for the full boundary layer has limited the availability of data characterizing the vertical structure of such gases above the canopy height and still in the boundary layer. This is an important region where many reactive VOCs are oxidized or otherwise removed. Here we describe an airborne sampling system designed to collect a vertical profile of air into a 3/8 in. OD (outer diameter tube 150 m in length. The inlet ram air pressure is used to flow sampled air through the tube, which results in a varying flow rate based on aircraft speed and altitude. Since aircraft velocity decreases during ascent, it is necessary to account for the variable flow rate into the tube. This is accomplished using a reference gas that is pulsed into the air stream so that the precise altitude of the collected air can be reconstructed post-collection. The pulsed injections are also used to determine any significant effect from diffusion/mixing within the sampling tube, either during collection or subsequent extraction for gas analysis. This system has been successfully deployed, and we show some measured vertical profiles of isoprene and its oxidation products methacrolein and methyl vinyl ketone from a mixed canopy near Columbia, Missouri.

  1. A novel Whole Air Sample Profiler (WASP) for the quantification of volatile organic compounds in the boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Mak, J. E.; Su, L.; Guenther, Alex B.; Karl, Thomas G.

    2013-10-16

    The emission and fate of reactive VOCs is of inherent interest to those studying chemical biosphere-atmosphere interactions. In-canopy VOC observations are obtainable using tower-based samplers, but the lack of suitable sampling systems for the full boundary 5 layer has limited the data characterizing the vertical structure of such gases above the canopy height and still in the boundary layer. This is the important region where many reactive VOCs are oxidized or otherwise removed. Here we describe an airborne sampling system designed to collect a vertical profile of air into a 3/800 OD tube 150m in length. The inlet ram air pressure is used to flow sampled air through the 10 tube, which results in a varying flow rate based on aircraft speed and altitude. Since aircraft velocity decreases during ascent, it is necessary to account for the variable flow rate into the tube. This is accomplished using a reference gas that is pulsed into the air stream so that the precise altitude of the collected air can be reconstructed post-collection. The pulsed injections are also used to determine any significant effect 15 from diffusion/mixing within the sampling tube, either during collection or subsequent extraction for gas analysis. This system has been successfully deployed, and we show some measured vertical profiles of isoprene and its oxidation products methacrolein and methyl vinyl ketone from a mixed canopy near Columbia, Missouri.

  2. Comparison of halocarbon measurements in an atmospheric dry whole air sample

    Directory of Open Access Journals (Sweden)

    George C. Rhoderick

    2015-11-01

    Full Text Available Abstract The growing awareness of climate change/global warming, and continuing concerns regarding stratospheric ozone depletion, will require continued measurements and standards for many compounds, in particular halocarbons that are linked to these issues. In order to track atmospheric mole fractions and assess the impact of policy on emission rates, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards. Precise measurements of these species aid in determining small changes in their atmospheric abundance. A common source of standards/scales and/or well-documented agreement of different scales used to calibrate the measurement instrumentation are key to understanding many sets of data reported by researchers. This report describes the results of a comparison study among National Metrology Institutes and atmospheric research laboratories for the chlorofluorocarbons (CFCs dichlorodifluoromethane (CFC-12, trichlorofluoromethane (CFC-11, and 1,1,2-trichlorotrifluoroethane (CFC-113; the hydrochlorofluorocarbons (HCFCs chlorodifluoromethane (HCFC-22 and 1-chloro-1,1-difluoroethane (HCFC-142b; and the hydrofluorocarbon (HFC 1,1,1,2-tetrafluoroethane (HFC-134a, all in a dried whole air sample. The objective of this study is to compare calibration standards/scales and the measurement capabilities of the participants for these halocarbons at trace atmospheric levels. The results of this study show agreement among four independent calibration scales to better than 2.5% in almost all cases, with many of the reported agreements being better than 1.0%.

  3. Concentrations of polybrominated diphenyl ethers (PBDEs) in central air-conditioner filter dust and relevance of non-dietary exposure in occupational indoor environments in Greece

    International Nuclear Information System (INIS)

    Polybrominated Diphenyl Ethers (PBDEs) are ubiquitous in the indoor environment owing to their use in consumer products and various studies around the world have found higher concentrations indoors than outdoors. Central air conditioner (A/C) systems have been widely used in many workplaces, therefore, studying of PBDEs in central A/C filter dust is useful to better understand the occurrences and health implications of PBDEs in indoor environments. The present study examined the occurrence of PBDEs in central A/C filter dust collected from various workplaces (n = 20) in Thessaloniki, Greece. The sum concentrations of 21 target congeners (∑21PBDE) in A/C dust ranged between 84 and 4062 ng g−1 with a median value of 1092 ng g−1, while BDE-209 was found to be the most abundant BDE congener. The daily intake via dust ingestion of PBDEs estimated for the employees of the occupational settings ranged from 3 to 45 ng day−1 (median 12 ng day−1). - Highlights: • PBDEs were investigated in dust of A/C filters in occupational settings in Thessaloniki, Greece. • BDE-209 was found to be the most abundant BDE congener. • High levels of PBDEs were found in a newspaper building, internet cafes and electronic shops. • PBDEs were attributable to the extensive presence and/or usage of electronic devices. • Exposure of employees to PBDEs via indoor dust ingestion was estimated at 12 ng day−1. - PBDEs were for the first time measured in dust from central A/C filters in workplaces of Greece and their concentrations were used to estimate the non-dietary human exposure

  4. Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

    OpenAIRE

    Nischkauer, Winfried; Vanhaecke, Frank; Bernacchi, Sébastien; Herwig, Christoph; Limbeck, Andreas

    2014-01-01

    Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts a...

  5. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  6. Screening for congenital cytomegalovirus infection using newborn urine samples collected on filter paper: feasibility and outcomes from a multicentre study.

    Science.gov (United States)

    Koyano, Shin; Inoue, Naoki; Oka, Akira; Moriuchi, Hiroyuki; Asano, Kimisato; Ito, Yushi; Yamada, Hideto; Yoshikawa, Tetsushi; Suzutani, Tatsuo

    2011-01-01

    Background As congenital cytomegalovirus (CMV) infection causes significant clinical consequences not only at birth but also later as neurological sequelae, it is critical to establish a strategy for screening congenitally infected newborns. Previous studies have identified an insufficient sensitivity in screening methods based on the use of dried blood spots (DBSs). Objectives To evaluate the feasibility of the authors' recently developed method for large-scale screening for congenital CMV infection and to identify risk factors for congenital infection. Methods More than 21 000 newborns were enrolled at 25 sites in six geographically separate areas of Japan. Urine was collected onto filter cards placed in the diapers, which were then analysed by quantitative PCR using the filter disc directly as a template. Clinical and physical findings of the newborns were extracted from their medical records. CMV strains from the cases and their siblings were genetically compared. Viral loads in DBSs obtained from some of the cases were compared with those in the urine filters. Results Congenital CMV infection was identified in 0.31% (95% CI 0.24% to 0.39%) of the newborns, and 30% of the cases (20/66) had typical clinical manifestations and/or showed abnormalities in brain images at birth. Although the positive predictive value of our screening was 94%, the lack of any comparison with a gold standard assay prevented calculation of the negative predictive value. Almost two-thirds of the cases had siblings, a significantly higher frequency than for uninfected newborns. Most of the cases (21/25) excreted CMV strains identical to those of their siblings. CMV DNA was undetectable in three out of 12 retrievable DBS specimens. Conclusions Implementation of an effective large-scale screening programme for congenital CMV infection is feasible. Siblings are the major risk factor for congenital CMV infection, which emphasises the need for education of mothers-to-be as well as vaccine

  7. MICROBIOLOGICAL SURVEILLANCE OF AIR QUALITY IN OPE RATION THEATRES - COMPARISON OF THE CONVENTIONAL SETTLE PL ATE TECHNIQUES VS USE OF AN AIR SAMPLING DEVICE.

    Directory of Open Access Journals (Sweden)

    Prathab

    2012-10-01

    Full Text Available ABSTRACT: BACKGROUND: Air as a means of nosocomial transmission has alw ays remained as a cause of concern for health care providers and especially personnel involved in infection control activities. Although there are no uniform c onsensus on either the standards for surveillance, methodology for monitoring or the lev els of acceptable contamination, it still remains a fact that we need to have some criteria t o monitor air quality in atleast the critical care areas like the operation theatres. METHODOLOGY: Air quality surveillance in the operation theatres was performed simultaneously usin g the settle plate technique and an air sampling device. A total of 9 operation theatres were subjected to 4 surveillance cycles with a minimum of 2 recordings in each theatre following standard protocols and accepted method used to calculate bioburden. RESULTS: A comparison was made between the two methods using the data available with 72 recordings . In th e settle plate technique, the mean cfu /mm3 was found to be 17.11 and 22cfu/mm3 at less than 30 cm and at a point more than 30cms of the operating table where as the corresponding means usi ng the air sampler was137.83 and 164.11cfu/mm3 respectively which showed considerable statistical significance . CONCLUSION : The use of an air sampler would be more appropriate in monitoring the air quality in critical care areas ensuring a more stringent method of qual ity check without compromising on the the standard accepted norms and addressing the issue of patient safety with reference to infection prevention

  8. Development of Methods for Sampling and Analysis of Polychlorinated Naphthalenes in Ambient Air

    Science.gov (United States)

    Erickson, Mitchell D.; And Others

    1978-01-01

    The procedure and sampler described permits detection of less than 50pg of one polychlorinated naphthalene (PCN) isomer. The method uses gas chromatography-mass spectrometry. The PCNs are collected on a glass fiber filter and two polyurethane foam plugs and extracted with toluene at 25 degrees Celsius. (BB)

  9. Neutron activitation analysis of an air-dust sample using a high-flux 14 Mev neutron generator

    International Nuclear Information System (INIS)

    The 14 MeV neutron activation analysis technique is illustrated for multielement analysis of a Milanese air-dust sample. The neutron generator and electronic system, the efficiency and flux calibration, the γ-ray background, the sample preparation and the peak analysis used are described. After careful corrections of all possible interferences and error calculations, the results of 24 elemental concentrations are compared with those of other analytical techniques in the scope of an interlaboratory test. (orig.)

  10. Pembuatan Dan Karakterisasi Karbon Aktif Kayu Bakau Dengan Aktivasi Fisika Sebagai Filter Penjernih Air Sungai Tamiang Melalui Proses Elektrokoagulasi

    OpenAIRE

    Putra, Zulkarnain

    2015-01-01

    The manufacture of Mangrove wood activated carbon with physical activation with temperature variation in 500 oC, 600 oC, 700 oC, 800 oC, and 900 oC for 1 hour detention time. This study aims to determine the best activation temperature of mangrove wood activated carbon used as a filter for the purification of river water. Based on SNI No. 06-3730-1995 thetesting results of mangrove wood activated carbon is best (optimum) with a water content of 4.25%, 9.88% volatile matter, ash content 2.44% ...

  11. Comparison between conventional biofilters and biotrickling filters applied to waste bio-drying in terms of atmospheric dispersion and air quality.

    Science.gov (United States)

    Schiavon, Marco; Ragazzi, Marco; Torretta, Vincenzo; Rada, Elena Cristina

    2016-01-01

    Biofiltration has been widely applied to remove odours and volatile organic compounds (VOCs) from industrial off-gas and mechanical-biological waste treatments. However, conventional open biofilters cannot guarantee an efficient dispersion of air pollutants emitted into the atmosphere. The aim of this paper is to compare conventional open biofilters with biotrickling filters (BTFs) in terms of VOC dispersion in the atmosphere and air quality in the vicinity of a hypothetical municipal solid waste bio-drying plant. Simulations of dispersion were carried out regarding two VOCs of interest due to their impact in terms of odours and cancer risk: dimethyl disulphide and benzene, respectively. The use of BTFs, instead of conventional biofilters, led to significant improvements in the odour impact and the cancer risk: when adopting BTFs instead of an open biofilter, the area with an odour concentration > 1 OU m(-3) and a cancer risk > 10(-6) was reduced by 91.6% and 95.2%, respectively. When replacing the biofilter with BTFs, the annual mean concentrations of odorants and benzene decreased by more than 90% in the vicinity of the plant. These improvements are achieved above all because of the higher release height of BTFs and the higher velocity of the outgoing air flow.

  12. Indoor Air Quality in Selected Samples of Primary Schools in Kuala Terengganu, Malaysia

    Directory of Open Access Journals (Sweden)

    Marzuki Ismail

    2010-01-01

    Full Text Available Studies have found out that indoor air quality affects human especially children and the elderly more compared to ambient atmospheric air. This study aims to investigate indoor air pollutants concentration in selected vernacular schools with different surrounding human activities in Kuala Terengganu, the administrative and commercial center of Terengganu state. Failure to identify and establish indoor air pollution status can increase the chance of long-term and short-term health problems for these young students and staff; reduction in productivity of teachers; and degrade the youngsters learning environment and comfort. Indoor air quality (IAQ parameters in three primary schools were conducted during the monsoon season of November 2008 for the purposes of assessing ventilation rates, levels of particulate matter (PM10 and air quality differences between schools. In each classroom, carbon monoxide (CO, CO2, air velocity, relative humidity and temperature were performed during school hours, and a complete walkthrough survey was completed. Results show a statistically significant difference for the five IAQ parameters between the three schools at the 95.0% confidence level. We conclude our findings by confirming the important influence of surrounding human activities on indoor concentrations of pollutants in selected vernacular schools in Kuala Terengganu.

  13. A spatial multicriteria model for determining air pollution at sample locations.

    Science.gov (United States)

    Réquia Júnior, Weeberb João; Roig, Henrique Llacer; Koutrakis, Petros

    2015-02-01

    Atmospheric pollution in urban centers has been one of the main causes of human illness related to the respiratory and circulatory system. Efficient monitoring of air quality is a source of information for environmental management and public health. This study investigates the spatial patterns of atmospheric pollution using a spatial multicriteria model that helps target locations for air pollution monitoring sites. The main objective was to identify high-priority areas for measuring human exposures to air pollutants as they relate to emission sources. The method proved to be viable and flexible in its application to various areas. PMID:25947058

  14. Performance enhancement of the single-phase series active filter by employing the load voltage waveform reconstruction and line current sampling delay reduction methods

    DEFF Research Database (Denmark)

    Senturk, O.S.; Hava, A.M.

    2011-01-01

    This paper proposes the waveform reconstruction method (WRM), which is utilized in the single-phase series active filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line...... current sampling delay reduction method, a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous-reference-frame-based methods. The analytical, simulation, and experimental studies of a 2.5 k......W single-phase SAF compensated system prove the theory....

  15. Research Project: Assessment of Lead in Air of Guatemala City

    International Nuclear Information System (INIS)

    In this report all the activities concerning to quality of air in the city of Guatemala are considered. By measurements of lead in filters of air sampling using voltametry, the quality of air is going to be compared with international standards

  16. Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

    Science.gov (United States)

    Nischkauer, Winfried; Vanhaecke, Frank; Bernacchi, Sébastien; Herwig, Christoph; Limbeck, Andreas

    2014-11-01

    Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple external calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL- 1 with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with

  17. 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.

  18. In situ monitoring of air sampling in ventilation stack from NPP using the spectrometer inspector 1000 with LaBr probe

    International Nuclear Information System (INIS)

    The system of gamma-spectrometric on-site measuring of mass activity Am of air-conditioning filters used in nuclear devices is described in contribution. Measures were taken in May and July 2008 in A1 NPP by device InSpector 1000 (In1k), primary assigned to measuring of dose rates. (authors)

  19. Review of Methods for Calculating Pressure Profiles of Explosive Air Blast and its Sample Application

    OpenAIRE

    Chock, Jeffrey Mun Kong

    1999-01-01

    Blast profiles and two primary methods of determining them were reviewed for use in the creation of a computer program for calculating blast pressures which serves as a design tool to aid engineers or analysts in the study of structures subjected to explosive air blast. These methods were integrated into a computer program, BLAST.F, to generate air blast pressure profiles by one of these two differing methods. These two methods were compared after the creation of the program and can conserv...

  20. A Predictive Model for Vehicle Air Exchange Rates based on a Large, Representative Sample

    OpenAIRE

    Fruin, Scott A.; Hudda, Neelakshi; Sioutas, Constantinos; Delfino, Ralph J.

    2011-01-01

    The in-vehicle microenvironment is an important route of exposure to traffic-related pollutants, particularly ultrafine particles. However, significant particle losses can occur under conditions of low air exchange rate (AER) when windows are closed and air is recirculating. AERs are lower for newer vehicles and at lower speeds. Despite the importance of AER in affecting in-vehicle particle exposures, few studies have characterized AER and all have tested only a small number of cars. One reas...

  1. Scheduling whole-air samples above the Trade Wind Inversion from SUAS using real-time sensors

    Science.gov (United States)

    Freer, J. E.; Greatwood, C.; Thomas, R.; Richardson, T.; Brownlow, R.; Lowry, D.; MacKenzie, A. R.; Nisbet, E. G.

    2015-12-01

    Small Unmanned Air Systems (SUAS) are increasingly being used in science applications for a range of applications. Here we explore their use to schedule the sampling of air masses up to 2.5km above ground using computer controlled bespoked Octocopter platforms. Whole-air sampling is targeted above, within and below the Trade Wind Inversion (TWI). On-board sensors profiled the TWI characteristics in real time on ascent and, hence, guided the altitudes at which samples were taken on descent. The science driver for this research is investigation of the Southern Methane Anomaly and, more broadly, the hemispheric-scale transport of long-lived atmospheric tracers in the remote troposphere. Here we focus on the practical application of SUAS for this purpose. Highlighting the need for mission planning, computer control, onboard sensors and logistics in deploying such technologies for out of line-of-sight applications. We show how such a platform can be deployed successfully, resulting in some 60 sampling flights within a 10 day period. Challenges remain regarding the deployment of such platforms routinely and cost-effectively, particularly regarding training and support. We present some initial results from the methane sampling and its implication for exploring and understanding the Southern Methane Anomaly.

  2. Control of oil-wetting on technical textiles by means of photo-chemical surface modification and its relevance to the performance of compressed air filters

    Energy Technology Data Exchange (ETDEWEB)

    Bahners, Thomas, E-mail: bahners@dtnw.de [Deutsches Textilforschungszentrum Nord-West gGmbH (DTNW), Adlerstr. 1, 47798 Krefeld (Germany); Mölter-Siemens, Wolfgang; Haep, Stefan [Institut für Energie- und Umwelttechnik e.V. (IUTA), Bliersheimer Str. 60, 47229 Duisburg (Germany); Gutmann, Jochen S. [Deutsches Textilforschungszentrum Nord-West gGmbH (DTNW), Adlerstr. 1, 47798 Krefeld (Germany); Universität Duisburg-Essen, Physikalische Chemie and CENIDE, Universitätsstr. 2, 45141 Essen (Germany)

    2014-09-15

    Highlights: • The oil repellence of textile fabrics was increased following the Wenzel concept. • Fiber surfaces were micro-roughened by means of pulsed UV laser irradiation. • Subsequent UV-induced grafting yielded pronounced oil repellence. • The grafting process conserved the delicate topography of the fiber surfaces. • The modified fabrics showed favorable drainage behavior in oil droplet separation. - Abstract: A two-step process comprising a surface roughening step by excimer laser irradiation and a post-treatment by photo-grafting to decrease the surface free energy was employed to increase the oil repellence of technical fabrics made of poly(ethylene terephthalate) (PET). The modification was designed to improve the performance of multi-layer filters for compressed air filtration, in which the fabrics served to remove, i.e. drain, oil separated from the air stream. In detail, the fibers surfaces were roughened by applying several laser pulses at a wavelength of 248 nm and subsequently photo-grafted with 1H,1H,2H,2H-perfluoro-decyl acrylate (PPFDA). The oil wetting behavior was increased by the treatments from full wetting on the as-received fabrics to highly repellent with oil contact angles of (131 ± 7)°. On surfaces in the latter state, oil droplets did not spread or penetrate even after one day. The grafting of PPFDA alone without any surface roughening yielded an oil contact angle of (97 ± 11)°. However, the droplet completely penetrated the fabric over a period of one day. The drainage performance was characterized by recording the pressure drop over a two-layer model filter as a function of time. The results proved the potential of the treatment, which reduced the flow resistance after 1-h operation by approximately 25%.

  3. Ultrasound-assisted dispersive liquid-liquid microextraction plus simultaneous silylation for rapid determination of salicylate and benzophenone-type ultraviolet filters in aqueous samples.

    Science.gov (United States)

    Wu, Jen-Wen; Chen, Hsin-Chang; Ding, Wang-Hsien

    2013-08-01

    A rapid procedure, using minimal amounts of solvent, for the reliable determination of five salicylate and benzophenone-type ultraviolet (UV) filters: ethylhexyl salicylate (EHS), 3,3,5-trimethyl-cyclohexyl salicylate (HMS), 2-hydroxy-4-methoxybenzophenone (BP-3), 2,4-dihydroxy-benzophenone (BP-1) and 2,2'-dihydroxy-4-methoxybenzophenone (BP-8), in aqueous samples is described. The method involves an ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) plus simultaneous silylation prior to their determination by gas chromatography-mass spectrometry (GC-MS). The parameters affecting the extraction and derivatization efficiency of the target UV filters from aqueous samples were systematically investigated and the conditions optimized. The optimal silylation and extraction conditions involved the rapid injection of a mixture of 750μL of acetone (as a dispersant), 15μL of tetrachloroethylene (as an extractant), and 20μL of BSTFA (as a derivatizing agent) into a 10-mL volume of aqueous samples (pH 7.0) containing 0.5g of sodium chloride in a glass tube with a conical bottom. After ultrasonication for 2.0min and centrifugation at 5000rpm (10min), the sedimented phase 5.0μL was directly introduced into the GC-MS. The limits of quantitation (LOQs) were less than 6ng/L. The precision for these analytes, as indicated by the relative standard deviations (RSDs), was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 74 and 92%. The method was then applied to environmental aqueous samples, using a standard addition method, showing the occurrence of BP-3 in samples of both river water and municipal wastewater treatment plant (MWTP) effluents. PMID:23831000

  4. Whole air canister sampling coupled with preconcentration GC/MS analysis of part-per-trillion levels of trimethylsilanol in semiconductor cleanroom air.

    Science.gov (United States)

    Herrington, Jason S

    2013-08-20

    The costly damage airborne trimethylsilanol (TMS) exacts on optics in the semiconductor industry has resulted in the demand for accurate and reliable methods for measuring TMS at trace levels (i.e., parts per trillion, volume per volume of air [ppt(v)] [~ng/m(3)]). In this study I developed a whole air canister-based approach for field sampling trimethylsilanol in air, as well as a preconcentration gas chromatography/mass spectrometry laboratory method for analysis. The results demonstrate clean canister blanks (0.06 ppt(v) [0.24 ng/m(3)], which is below the detection limit), excellent linearity (a calibration relative response factor relative standard deviation [RSD] of 9.8%) over a wide dynamic mass range (1-100 ppt(v)), recovery/accuracy of 93%, a low selected ion monitoring method detection limit of 0.12 ppt(v) (0.48 ng/m(3)), replicate precision of 6.8% RSD, and stability (84% recovery) out to four days of storage at room temperature. Samples collected at two silicon wafer fabrication facilities ranged from 10.0 to 9120 ppt(v) TMS and appear to be associated with the use of hexamethyldisilazane priming agent. This method will enable semiconductor cleanroom managers to monitor and control for trace levels of trimethylsilanol.

  5. Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks.

    Science.gov (United States)

    Nischkauer, Winfried; Vanhaecke, Frank; Bernacchi, Sébastien; Herwig, Christoph; Limbeck, Andreas

    2014-11-01

    Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple external calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL(- 1) with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with

  6. Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks☆

    Science.gov (United States)

    Nischkauer, Winfried; Vanhaecke, Frank; Bernacchi, Sébastien; Herwig, Christoph; Limbeck, Andreas

    2014-01-01

    Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple external calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL− 1 with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with

  7. Air

    Science.gov (United States)

    ... house) Industrial emissions (like smoke and chemicals from factories) Household cleaners (spray cleaners, air fresheners) Car emissions (like carbon monoxide) *All of these things make up “particle pollution.” They mostly come from cars, trucks, buses, and ...

  8. Detection of Campylobacter bacteria in air samples for continuous real-time monitoring of Campylobacter colonization in broiler flocks.

    Science.gov (United States)

    Olsen, Katja N; Lund, Marianne; Skov, Julia; Christensen, Laurids S; Hoorfar, Jeffrey

    2009-04-01

    Improved monitoring tools are important for the control of Campylobacter bacteria in broiler production. In this study, we compare the sensitivities of detection of Campylobacter by PCR with feces, dust, and air samples during the lifetimes of broilers in two poultry houses and conclude that the sensitivity of detection of Campylobacter in air is comparable to that in other sample materials. Profiling of airborne particles in six poultry houses revealed that the aerodynamic conditions were dependent on the age of the chickens and very comparable among different poultry houses, with low proportions of particles in the 0.5- to 2-microm-diameter range and high proportions in the 2- to 5-microm-diameter range. Campylobacter could also be detected by PCR in air samples collected at the hanging stage during the slaughter process but not at the other stages tested at the slaughterhouse. The exploitation of airborne dust in poultry houses as a sample material for the detection of Campylobacter and other pathogens provides an intriguing possibility, in conjunction with new detection technologies, for allowing continuous or semicontinuous monitoring of colonization status.

  9. The lung cancer breath signature: a comparative analysis of exhaled breath and air sampled from inside the lungs

    Science.gov (United States)

    Capuano, Rosamaria; Santonico, Marco; Pennazza, Giorgio; Ghezzi, Silvia; Martinelli, Eugenio; Roscioni, Claudio; Lucantoni, Gabriele; Galluccio, Giovanni; Paolesse, Roberto; di Natale, Corrado; D'Amico, Arnaldo

    2015-11-01

    Results collected in more than 20 years of studies suggest a relationship between the volatile organic compounds exhaled in breath and lung cancer. However, the origin of these compounds is still not completely elucidated. In spite of the simplistic vision that cancerous tissues in lungs directly emit the volatile metabolites into the airways, some papers point out that metabolites are collected by the blood and then exchanged at the air-blood interface in the lung. To shed light on this subject we performed an experiment collecting both the breath and the air inside both the lungs with a modified bronchoscopic probe. The samples were measured with a gas chromatography-mass spectrometer (GC-MS) and an electronic nose. We found that the diagnostic capability of the electronic nose does not depend on the presence of cancer in the sampled lung, reaching in both cases an above 90% correct classification rate between cancer and non-cancer samples. On the other hand, multivariate analysis of GC-MS achieved a correct classification rate between the two lungs of only 76%. GC-MS analysis of breath and air sampled from the lungs demonstrates a substantial preservation of the VOCs pattern from inside the lung to the exhaled breath.

  10. A new CF-IRMS system for quantifying stable isotopes of carbon monoxide from ice cores and small air samples

    Directory of Open Access Journals (Sweden)

    Z. Wang

    2010-10-01

    Full Text Available We present a new analysis technique for stable isotope ratios (δ13C and δ18O of atmospheric carbon monoxide (CO from ice core samples. The technique is an online cryogenic vacuum extraction followed by continuous-flow isotope ratio mass spectrometry (CF-IRMS; it can also be used with small air samples. The CO extraction system includes two multi-loop cryogenic cleanup traps, a chemical oxidant for oxidation to CO2, a cryogenic collection trap, a cryofocusing unit, gas chromatography purification, and subsequent injection into a Finnigan Delta Plus IRMS. Analytical precision of 0.2‰ (±1δ for δ13C and 0.6‰ (±1δ for δ18O can be obtained for 100 mL (STP air samples with CO mixing ratios ranging from 60 ppbv to 140 ppbv (~268–625 pmol CO. Six South Pole ice core samples from depths ranging from 133 m to 177 m were processed for CO isotope analysis after wet extraction. To our knowledge, this is the first measurement of stable isotopes of CO in ice core air.

  11. Filter-adsorber aging assessment

    International Nuclear Information System (INIS)

    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

  12. 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)

    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

  13. Air pollution sampling of particles. (Latest citations from the NTIS bibliographic database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The bibliography contains citations concerning the techniques of sampling particles in the Earth`s atmosphere. Sampling procedures, sampler design and performance, site selection, sampling networks, and meteorological effects are discussed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  14. Air

    International Nuclear Information System (INIS)

    In recent years several regulations and standards for air quality and limits for air pollution were issued or are in preparation by the European Union, which have severe influence on the environmental monitoring and legislation in Austria. This chapter of the environmental control report of Austria gives an overview about the legal situation of air pollution control in the European Union and in specific the legal situation in Austria. It gives a comprehensive inventory of air pollution measurements for the whole area of Austria of total suspended particulates, ozone, volatile organic compounds, nitrogen oxides, sulfur dioxide, carbon monoxide, heavy metals, benzene, dioxin, polycyclic aromatic hydrocarbons and eutrophication. For each of these pollutants the measured emission values throughout Austria are given in tables and geographical charts, the environmental impact is discussed, statistical data and time series of the emission sources are given and legal regulations and measures for an effective environmental pollution control are discussed. In particular the impact of fossil-fuel power plants on the air pollution is analyzed. (a.n.)

  15. Sampling

    CERN Document Server

    Thompson, Steven K

    2012-01-01

    Praise for the Second Edition "This book has never had a competitor. It is the only book that takes a broad approach to sampling . . . any good personal statistics library should include a copy of this book." —Technometrics "Well-written . . . an excellent book on an important subject. Highly recommended." —Choice "An ideal reference for scientific researchers and other professionals who use sampling." —Zentralblatt Math Features new developments in the field combined with all aspects of obtaining, interpreting, and using sample data Sampling provides an up-to-date treat

  16. Filter-aided sample preparation with dimethyl labeling to identify and quantify milk fat globule membrane proteins.

    NARCIS (Netherlands)

    Lu, J.; Boeren, J.A.; Vries, de S.C.; Valenberg, van H.J.F.; Vervoort, J.J.M.; Hettinga, K.A.

    2011-01-01

    Bovine milk is a major nutrient source in many countries and it is produced at an industrial scale. Milk is a complex mixture of proteins, fats, carbohydrates, vitamins and minerals. The composition of the bovine milk samples can vary depending on the genetic makeup of the bovine species as well as

  17. Aerosol sampling methods for wide area environmental sampling (WAES). Finnish support to IAEA

    International Nuclear Information System (INIS)

    Enrichment of uranium or reprocessing of nuclear fuel are expected to produce releases of non-natural radionuclides, that are carried away in air attached in airborne particles. Wide Area Environmental Sampling (WAES)-method utilises air samplers distributed in the monitored area to detect the possible releases. For reduction of expenses, the samplers located in remote areas should be able to operate long periods of time unattended. In this work, a high-volume (flow rate 150 m3/h) air sampler with an automatic filter changing system, Hunter MKII, was developed for WAES. The sampler can collect six one-week samples until it needs to be visited for unloading the used filters and loading the new ones. The device sends real-time state-of-health information to headquarters so that longtime loss of sampling can be avoided in case of malfunction. The state-of-health data also includes indication to prevent inconspicuous tampering of the unattended sampling process. Organic filter materials are used to collect particles due to their applicability to radiochemical analysis. Four filter materials were tested for collection efficiency and pressure drop. The material selected for current use (Petrianov FPP-15-1.5 used as two-layers one upon the other) can collect more than 90% of the 0.2 μm particles throughout the sampling period. If there is a large concentration of coarse particles in air (as is typically the case in desert conditions), the filter clogging rate can be significantly decreased by preceding it with a low-pressure-drop pre-filter that collects the coarse particles. The filter pressure drop is low enough to easily allow one-week sampling time in typical sampling conditions (a pre-filter may be needed in heavily dust laden desert air). (orig.)

  18. Application of Solid Phase Microextraction followed by Chromatograph-Flame Ionization Detector for Sampling and Analysis of Acetonitrile in Air

    OpenAIRE

    NEMATULLAH KURD; ABDULRAHMAN BAHRAMI; FARSHID GHORBANI-SHAHNA; MAHMOUD HEIDARI

    2015-01-01

    Acetonitrile used as a solvent in manufactures and affects to central nervous system from inhalation exposure. The aim of this study was to develop a micro-solid phase extraction method for the determination of acetonitrile in the air matrix. The sampling was performed with a small diameter fused silica fiber coated with a thin film of stationary phase and was subsequently desorbed and analyzed by gas chromatograph equipped with a flame ionization detector (GC/FID). The effects of laboratory ...

  19. Regional CO2 fluxes inferred from mixing ratio measurements: estimates from flask air samples in central Kansas, USA

    OpenAIRE

    Lai, Chun-Ta; Schauer, Andrew J.; Owensby, Clenton; Ham, Hay M.; Helliker, Brent; Tans, Pieter P.; Ehleringer, James R

    2011-01-01

    We estimated regional fluxes of carbon dioxide (CO2) using mixing ratios measured in a tallgrass prairie in central Kansas, USA over 3 yr (2002–2004). Glass flasks were used to collect whole air samples in the midafternoon for determining CO2 mixing ratios and their carbon isotopic composition. Regional CO2 fluxes were calculated assuming atmospheric boundary layer (ABL) approaches an equilibrium state on a monthly basis. CO2 mixing ratios derived from the marine boundary layer data were used...

  20. Extent of sample loss on the sampling device and the resulting experimental biases when collecting volatile fatty acids (VFAs) in air using sorbent tubes.

    Science.gov (United States)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2013-08-20

    Not all volatile organic compounds (VOCs) are suitable for sampling from air onto sorbent tubes (ST) with subsequent analysis by thermal desorption (TD) with gas chromatography (GC). Some compounds (such as C2 hydrocarbons) are too volatile for quantitative retention by sorbents at ambient temperature, while others are too reactive - either for storage stability on the tubes (post-sampling) or for thermal desorption/GC analysis. Volatile fatty acids (VFAs) are one of the compound groups that present a challenge to sorbent tube sampling. In this study, we evaluated sample losses on the inner wall surface of the sorbent tube sampler. The sorptive losses of five VFA (acetic, propionic, n-butyric, i-valeric, and n-valeric acid) were tested using two types of tubes (stainless steel and quartz), each packed with three sorbent beds arranged in order of sorbent strength from the sampling end of the tube (Tenax TA, Carbopack B, and Carbopack X). It showed significantly higher losses of VFAs in both liquid phase and vapor phase when using stainless steel tube samplers. These losses were also seen if vapor-phase fatty acids were passed through empty stainless steel tubing and increased dramatically with increasing molecular weight, e.g., losses of 33.6% (acetic acid) to 97.5% (n-valeric acid). Similar losses of VFAs were also observed from headspace sampling of cheese products. Considering that stainless steel sampling tubes are still used extensively by many researchers, their replacement with quartz tubes is recommended to reduce systematic biases in collecting VFA samples or in their calibration. PMID:23869450

  1. Effect of Sampling Depth on Air-Sea CO2 Flux Estimates in River-Stratified Arctic Coastal Waters

    Science.gov (United States)

    Miller, L. A.; Papakyriakou, T. N.

    2015-12-01

    In summer-time Arctic coastal waters that are strongly influenced by river run-off, extreme stratification severely limits wind mixing, making it difficult to effectively sample the surface 'mixed layer', which can be as shallow as 1 m, from a ship. During two expeditions in southwestern Hudson Bay, off the Nelson, Hayes, and Churchill River estuaries, we confirmed that sampling depth has a strong impact on estimates of 'surface' pCO2 and calculated air-sea CO2 fluxes. We determined pCO2 in samples collected from 5 m, using a typical underway system on the ship's seawater supply; from the 'surface' rosette bottle, which was generally between 1 and 3 m; and using a niskin bottle deployed at 1 m and just below the surface from a small boat away from the ship. Our samples confirmed that the error in pCO2 derived from typical ship-board versus small-boat sampling at a single station could be nearly 90 μatm, leading to errors in the calculated air-sea CO2 flux of more than 0.1 mmol/(m2s). Attempting to extrapolate such fluxes over the 6,000,000 km2 area of the Arctic shelves would generate an error approaching a gigamol CO2/s. Averaging the station data over a cruise still resulted in an error of nearly 50% in the total flux estimate. Our results have implications not only for the design and execution of expedition-based sampling, but also for placement of in-situ sensors. Particularly in polar waters, sensors are usually deployed on moorings, well below the surface, to avoid damage and destruction from drifting ice. However, to obtain accurate information on air-sea fluxes in these areas, it is necessary to deploy sensors on ice-capable buoys that can position the sensors in true 'surface' waters.

  2. Application of Solid Phase Microextraction followed by Chromatograph-Flame Ionization Detector for Sampling and Analysis of Acetonitrile in Air

    Directory of Open Access Journals (Sweden)

    NEMATULLAH KURD

    2015-10-01

    Full Text Available Acetonitrile used as a solvent in manufactures and affects to central nervous system from inhalation exposure. The aim of this study was to develop a micro-solid phase extraction method for the determination of acetonitrile in the air matrix. The sampling was performed with a small diameter fused silica fiber coated with a thin film of stationary phase and was subsequently desorbed and analyzed by gas chromatograph equipped with a flame ionization detector (GC/FID. The effects of laboratory and sampling parameters were investigated and applied to the determination of acetonitrile in air matrix. The Carboxen/PDMS as thecoating fiber showed better analytical performances compared to the PDMS fiber. Analysis of the data by ANOVA test at a 0.05 level of accuracy showed that the peak area of the sampler was significantly affected by temperature and humidity so that the optimum temperature was 20°C and the optimum humidity was 35%. Besides, the limit of detection (LOD and limit of quantification (LOQ for acetonitrile in the GC system were 0.05 and 0.15 μg/ml, respectively. The solid phase microextraction (SPME has been shown a suitable technique for sampling and analysis of acetonitrile in air. There was a good correlation between the SPME and national institute occupational safety and health (NIOSH 1010 method under the optimum conditions. 

  3. Secondary Pollutants from Ozone Reaction with Ventilation Filters and Degradation of Filter Media Additives

    Energy Technology Data Exchange (ETDEWEB)

    Destaillats, Hugo; Chen, Wenhao; Apte, Michael; Li, Nuan; Spears, Michael; Almosni, Jérémie; Brunner, Gregory; Zhang, Jianshun (Jensen); Fisk, William J.

    2011-05-01

    Prior research suggests that chemical processes taking place on the surface of particle filters employed in buildings may lead to the formation of harmful secondary byproducts. We investigated ozone reactions with fiberglass, polyester, cotton/polyester and polyolefin filter media, as well as hydrolysis of filter media additives. Studies were carried out on unused media, and on filters that were installed for 3 months in buildings at two different locations in the San Francisco Bay Area. Specimens from each filter media were exposed to {approx}150 ppbv ozone in a flow tube under a constant flow of dry or humidified air (50percent RH). Ozone breakthrough was recorded for each sample over periods of {approx}1000 min; the ozone uptake rate was calculated for an initial transient period and for steady-state conditions. While ozone uptake was observed in all cases, we did not observe significant differences in the uptake rate and capacity for the various types of filter media tested. Most experiments were performed at an airflow rate of 1.3 L/min (face velocity = 0.013 m/s), and a few tests were also run at higher rates (8 to 10 L/min). Formaldehyde and acetaldehyde, two oxidation byproducts, were quantified downstream of each sample. Those aldehydes (m/z 31 and 45) and other volatile byproducts (m/z 57, 59, 61 and 101) were also detected in real-time using Proton-Transfer Reaction - Mass Spectrometry (PTR-MS). Low-ppbv byproduct emissions were consistently higher under humidified air than under dry conditions, and were higher when the filters were loaded with particles, as compared with unused filters. No significant differences were observed when ozone reacted over various types of filter media. Fiberglass filters heavily coated with impaction oil (tackifier) showed higher formaldehyde emissions than other samples. Those emissions were particularly high in the case of used filters, and were observed even in the absence of ozone, suggesting that hydrolysis of additives

  4. CARBONIZED FIBROUS RESIN AS A NEW SORBENT FOR SAMPLING POLYCYCLIC AROMATIC HYDROCARBONS (PAHS)IN AMBIENT AIR

    Institute of Scientific and Technical Information of China (English)

    LINGDaren; LIUBing; 等

    2002-01-01

    A new sampling method of ambient air analysis using carbonized fibrous resin as a sorbent for polycyclic aromatic hydrocarbons(PAHs) was reported.The physical and chemical properties of the carbonized fibrous resins were measured.The sample pretreatment with ultrasonic extraction and subsequent clean-up elution through a silica gel column was optimized.The suitable ultrasonic extraction conditions were selected as follows:resin weight was 1.5g,ultrasonic extraction time 20min,volume of extraction solvent 100 ml and extraction operation times 2-3.The concentrated extractable organic matter was submitted to next step of clean-up procedure of adsorption chromatography on silica gel column/n-hexane and a mixture of dichloromethene:n-hexane solution 2:3(v/v).The PAHs fractions in the real samples from Changzhou,China were particularly analyzed using GC-MS data system and the data of mass spectra,retention times and scan numbers of the real samples were compared with that of the standards of 16 PAHs listed by the US EPA as “priority pollutants” of the environment. The pretreatment of samples of ambient air with carbonized fibrous resin as a sorbent for PAHs is proved to be reliable and might be used for the procedure of the determination of PAHs in atmospheric environment.

  5. Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang, China

    Directory of Open Access Journals (Sweden)

    H. Akimoto

    2012-06-01

    Full Text Available HO2 uptake coefficients for ambient aerosol particles, collected on quartz filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. Tai site were ranged from 0.13 to 0.34, while those at the Mt. Mang site were in the range of 0.09–0.40. These values are generally larger than those previously reported for single-component particles, suggesting that the minor components such as metal ions and organics in the particle could contribute to the HO2 uptake. A box model calculation suggested that the heterogeneous loss of HO2 by ambient particles could significantly affect the HOx concentrations and chemistry.

  6. Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang (China

    Directory of Open Access Journals (Sweden)

    H. Akimoto

    2012-12-01

    Full Text Available HO2 uptake coefficients for ambient aerosol particles, collected on quartz fiber filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. Tai site were ranged from 0.13 to 0.34, while those at the Mt. Mang site were in the range of 0.09–0.40. These values are generally larger than those previously reported for single-component particles, suggesting that reactions with the minor components such as metal ions and organics in the particle could contribute to the HO2 uptake. A box model calculation suggested that the heterogeneous loss of HO2 by ambient particles could significantly affect atmospheric HOx concentrations and chemistry.

  7. Mezcla génica en una muestra poblacional de la ciudad de Buenos Aires Gene mixture in a population sample from Buenos Aires City

    Directory of Open Access Journals (Sweden)

    Sergio A. Avena

    2006-04-01

    Full Text Available Este estudio tiene como objetivo estimar la mezcla génica en la población de la Ciudad de Buenos Aires, a partir de muestras de dadores de sangre provenientes de un centro público de salud (Hospital de Clínicas. Los estudios se realizaron sobre 218 personas no emparentadas que donaron su sangre durante el año 2002. Se analizaron 8 sistemas genéticos eritrocitarios y los alotipos GM/KM. Se realizó una encuesta con la finalidad de obtener información sobre lugar de nacimiento, residencia actual y datos genealógicos de los dadores. Las frecuencias génicas se determinaron empleando métodos de máxima verosimilitud. Para calcular la mezcla génica se aplicó el programa ADMIX (trihíbrido. Se registró un 15.8% de aporte indígena (AI y 4.3% de africano (AA. Estos datos se compararon con un estudio previo realizado en un centro privado (Hospital Italiano de Buenos Aires, no observándose diferencias significativas salvo en el sistema Km. Los resultados obtenidos se corresponden con la información histórica y demográfica de la ciudad de Buenos Aires.The aim of this study is to estimate the gene admixture in the population of Buenos Aires City from samples of blood donors, which come from a public health centre (Hospital de Clínicas. These studies were performed on 218 unrelated people, who donated blood during the year 2002. Eight erythrocyte genetic systems and GM/KM allotypes were analysed. A survey to obtain information about place of birth, present residence and genealogical data of the donors was performed. The gene frequencies were determined using a method of maximum likelihood. The genetic admixture was calculated through the ADMIX program (trihibride. The Amerindian and African contributions were 15.8% and 4.3% respectively. These data were compared with those obtained in a previous study performed in a private centre (Hospital Italiano de Buenos Aires and significant differences were observed, except in the KM system. The

  8. The Successful Diagnosis and Typing of Systemic Amyloidosis Using A Microwave-Assisted Filter-Aided Fast Sample Preparation Method and LC/MS/MS Analysis.

    Science.gov (United States)

    Sun, Weiyi; Sun, Jian; Zou, Lili; Shen, Kaini; Zhong, Dingrong; Zhou, Daobin; Sun, Wei; Li, Jian

    2015-01-01

    Laser microdissection followed by mass spectrometry has been successfully used for amyloid typing. However, sample contamination can interfere with proteomic analysis, and overnight digestion limits the analytical throughput. Moreover, current quantitative analysis methods are based on the spectrum count, which ignores differences in protein length and may lead to misdiagnoses. Here, we developed a microwave-assisted filter-aided sample preparation (maFASP) method that can efficiently remove contaminants with a 10-kDa cutoff ultrafiltration unit and can accelerate the digestion process with the assistance of a microwave. Additionally, two parameters (P- and D-scores) based on the exponentially modified protein abundance index were developed to define the existence of amyloid deposits and those causative proteins with the greatest abundance. Using our protocol, twenty cases of systemic amyloidosis that were well-typed according to clinical diagnostic standards (training group) and another twenty-four cases without subtype diagnoses (validation group) were analyzed. Using this approach, sample preparation could be completed within four hours. We successfully subtyped 100% of the cases in the training group, and the diagnostic success rate in the validation group was 91.7%. This maFASP-aided proteomic protocol represents an efficient approach for amyloid diagnosis and subtyping, particularly for serum-contaminated samples. PMID:25984759

  9. Passive air sampling of organochlorine pesticides in a northeastern state of India, Manipur

    Institute of Scientific and Technical Information of China (English)

    Ningombam Linthoingambi Devi; Shihua Qi; Paromita Chakraborty; Gan Zhang; Ishwar Chandra Yadav

    2011-01-01

    Thirty-six polyurethane foam disk passive air samplers (PUF-PAS) were deployed over a year during January to December, 2009 at three locations, i.e., Imphal (urban site), Thoubal (rural site) and Waithou (alpine site) of Manipur, to assess the seasonal local atrnospheric emission of selected organochlorine pesticides (OCPs).The average concentration of HCHs monitored at mountain site during hot season (Mar, Apr, and May) and rainy seasons (Jun, Jul, Aug, and Sep) were 403 and 349 pg/m3, respectively.DDTs had a high concentration with 384 pg/m3 at rural site and 379 pg/m3 at urban site during hot seasons.Endosulfans and chlordane were found high in concentration during hot seasons (260 pg/m3) and low during retreating monsoon seasons (44 pg/m3) at rural site.Most of the OCPs concentrations were high during cultivation period.The OCP concentrations of rainy season were highly correlated (p < 0.01) with OCPs of hot seasons.Further, positive correlation (p < 0.05) was also obtained between cold seasons and retreating monsoon.Principal component analysis showed a significant correlation among the four seasons and distribution pattern of OCPs in air.Back trajectory analysis by using HYPSLIT model showed a long range air transport of OCPs to the present study area.Present OCP levels at Manipur is an outcome of both local emission and also movement of air mass by long range atmospheric transport.

  10. Remote Mass Spectrometric Sampling of Electrospray- and Desorption Electrospray-Generated Ions Using an Air Ejector

    OpenAIRE

    Dixon, R. Brent; Bereman, Michael S.; Muddiman, David C.; Hawkridge, Adam M.

    2007-01-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrom...

  11. Kalman Filtering of Radar Technology in Air Traffic Control Surveillance System%浅析卡尔曼雷达滤波技术在空管监视系统中的应用

    Institute of Scientific and Technical Information of China (English)

    周君

    2015-01-01

    [Abstract]Kalman filter for radar surveillance technology in air traffic control systems were analyzed. Discuss the corresponding Kalman filtering techniques: Related adaptive Kalman filtering, multi-model adaptive Kalman filter, adaptive Kalman filter information based on neural network adaptive Kalman filtering, fuzzy logic adaptive Kalman filtering, and their main advantages and disadvantages of the problem.%对卡尔曼雷达滤波技术在空管监视系统中的应用进行了分析,讨论了相应的卡尔曼滤波技术:相关自适应卡尔曼滤波、多模型自适应卡尔曼滤波、基于信息的自适应卡尔曼滤波、神经网络自适应卡尔曼滤波、模糊逻辑自适应卡尔曼滤波,并对它们主要解决的问题及优缺点进行了分析。

  12. Large scale air monitoring: Biological indicators versus air particulate matter

    International Nuclear Information System (INIS)

    Biological indicator organisms are widely used for monitoring and banking purposes since many years. Although the complexity of the interactions between bioorganisms and their environment is generally not easily comprehensible, environmental quality assessment using the bioindicator approach offers some convincing advantages compared to direct analysis of soil, water, or air. Direct measurement of air particulates is restricted to experienced laboratories with access to expensive sampling equipment. Additionally, the amount of material collected generally is just enough for one determination per sampling and no multidimensional characterization might be possible. Further, fluctuations in air masses have a pronounced effect on the results from air filter sampling. Combining the integrating property of bioindicators with the world wide availability and uniform matrix characteristics of air particulates as a prerequisite for global monitoring of air pollution will be discussed. A new approach for sampling urban dust using large volume filtering devices installed in air conditioners of large hotel buildings is assessed. A first experiment was initiated to collect air particulates (300 to 500 g each) from a number of hotels during a period of three to four months by successive vacuum cleaning of used inlet filters from high volume air conditioning installations reflecting average concentrations per three months in different large cities. This approach is expected to be upgraded and applied for global monitoring. Highly positive correlated elements were found in lichen such as K/S, Zn/P, the rare earth elements (REE) and a significant negative correlation between Fig and Cu was observed in these samples. The ratio of concentrations of elements in dust and Usnea spp. is highest for Cr, Zn, and Fe (400-200) and lowest for elements such as Ca, Rb, and Sr (20-10). (author)

  13. Passive air sampler as a tool for long-term air pollution monitoring: Part 2. Air genotoxic potency screening assessment

    International Nuclear Information System (INIS)

    The capability of passive air sampling to be employed in the evaluation of direct genotoxicity of ambient air samples was assessed. Genotoxic effects of the total extracts from the polyurethane foam filters exposed for 28 days during a regional passive air sampling campaign were investigated. Twenty sampling sites were selected in Brno city on the area of approximately 20 x 20 km in October and November 2004. Brno is the second largest city of the Czech Republic, highly industrialized with approximately 370,000 of permanent inhabitants. The levels of PAHs, PCBs, and chlorinated pesticides were determined in all samples. Fraction of each extract was also assayed in the bacterial genotoxicity test using Escherichia coli sulA::lacZ. Complete dose-response relationships of the air extracts were determined. The statistical analysis showed significant correlation between observed biological effects and PAHs concentrations in samples. - Extracts from passive air samples can be used to assess genotoxic potency

  14. Incident-response monitoring technologies for aircraft cabin air quality

    Science.gov (United States)

    Magoha, Paul W.

    Poor air quality in commercial aircraft cabins can be caused by volatile organophosphorus (OP) compounds emitted from the jet engine bleed air system during smoke/fume incidents. Tri-cresyl phosphate (TCP), a common anti-wear additive in turbine engine oils, is an important component in today's global aircraft operations. However, exposure to TCP increases risks of certain adverse health effects. This research analyzed used aircraft cabin air filters for jet engine oil contaminants and designed a jet engine bleed air simulator (BAS) to replicate smoke/fume incidents caused by pyrolysis of jet engine oil. Field emission scanning electron microscopy (FESEM) with X-ray energy dispersive spectroscopy (EDS) and neutron activation analysis (NAA) were used for elemental analysis of filters, and gas chromatography interfaced with mass spectrometry (GC/MS) was used to analyze used filters to determine TCP isomers. The filter analysis study involved 110 used and 90 incident filters. Clean air filter samples exposed to different bleed air conditions simulating cabin air contamination incidents were also analyzed by FESEM/EDS, NAA, and GC/MS. Experiments were conducted on a BAS at various bleed air conditions typical of an operating jet engine so that the effects of temperature and pressure variations on jet engine oil aerosol formation could be determined. The GC/MS analysis of both used and incident filters characterized tri- m-cresyl phosphate (TmCP) and tri-p-cresyl phosphate (TpCP) by a base peak of an m/z = 368, with corresponding retention times of 21.9 and 23.4 minutes. The hydrocarbons in jet oil were characterized in the filters by a base peak pattern of an m/z = 85, 113. Using retention times and hydrocarbon thermal conductivity peak (TCP) pattern obtained from jet engine oil standards, five out of 110 used filters tested had oil markers. Meanwhile 22 out of 77 incident filters tested positive for oil fingerprints. Probit analysis of jet engine oil aerosols obtained

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

    International Nuclear Information System (INIS)

    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)

  16. 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.

  17. Detection of IgM antibodies against Toxoplasma gondii in blood samples absorbed onto filter paper, in order to assess a baseline for the occurence of congenital toxoplasma infections

    NARCIS (Netherlands)

    Conyn-van Spaendonck MAE; van Knapen F

    1990-01-01

    This report deals in the first place with some investigations on the utility of blood samples absorbed onto filter paper for determination of antibodies to Toxoplasma gondii. Secondly, the results of specific IgM detection in such samples of a cohort of neonates born in 1986/1987 are reported. The

  18. Survey of HEPA filter experience

    International Nuclear Information System (INIS)

    A survey of high efficiency particulate air (HEPA) filter applications and experience at Department of Energy (DOE) sites was conducted to provide an overview of the reasons and magnitude of HEPA filter changeouts and failures. Results indicated that approximately 58% of the filters surveyed were changed out in the three year study period, and some 18% of all filters were changed out more than once. Most changeouts (63%) were due to the existence of a high pressure drop across the filter, indicative of filter plugging. Other reasons for changeout included leak-test failure (15%), preventive maintenance service life limit (13%), suspected damage (5%) and radiation buildup (4%). Filter failures occurred with approximately 12% of all installed filters. Of these failures, most (64%) occurred for unknown or unreported reasons. Handling or installation damage accounted for an additional 19% of reported failures. Media ruptures, filter-frame failures and seal failures each accounted for approximately 5 to 6% of the reported failures

  19. Technical rationale and sampling procedures for assessing the effects of subsurface volatile organic contaminants on indoor air quality

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.T.; Agar, J.G. [O' Connor Associates Environmental Inc., Calgary, AB (Canada); Gregoire, M.Y. [O' Connor Associates Environmental Inc., Winnipeg, MB (Canada)

    2003-07-01

    Volatile organic compounds (VOC) can affect indoor air quality through vapours released indoors by cigarette smoke, building materials, and common household solvents and cleaners. Therefore, the level of VOC contaminants might be a reliable indicator of the impact due to subsurface contamination. The following method of indirect assessment has been accepted by Canadian and American environmental regulatory bodies. This accepted method involves soil gas sampling close to the basement or ground floor slab of a building and VOC vapour transport modeling in order to estimate soil gas flow rates and VOC flux into a building. VOC flux concentration can be used to evaluate the potential human exposure to soil or groundwater derived VOCs, and to estimate the associated human health risks. This paper describes the shallow vapour sampler and sampling procedure specifically designed for collecting representative soil gas samples in the zone adjacent to a building basement or a ground floor slab, which was developed by O'Connor Associates. The results of numerical modeling, and the technical rationale behind the design of a soil gas sampling program for different soil types were presented. Soil type, depth to groundwater, and sampling well construction and their respective influence were discussed with reference to soil gas sampling programs and human health risk evaluations. 12 refs., 5 tabs., 6 figs.

  20. Auditing of sampling methods for air toxics at coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Agbede, R.O.; Clements, J.L.; Grunebach, M.G. [Advanced Technology Systems, Inc., Monroeville, PA (United States)] [and others

    1995-11-01

    Advanced Technology Systems, Inc. (ATS) with subcontract assistance from international Technology Corporation (IT) has provided external audit activities for Phase II of the Department of Energy-Pittsburgh Energy Technology Center`s air emission test program. The objective of the audits is to help ensure that the data obtained from the emission tests are precise, accurate, representative, scientifically sound and legally defensible. This paper presents the criteria that were used to perform the external audits of the emission test program. It also describes the approach used by ATS and It in performing their audits. Examples of findings of the audits along with the actions take to correct problems and the subsequent effect of those actions on the test data are presented. The results of audit spikes performed at the Plant 1 test site are also discussed.

  1. Tuning the target composition of amine-grafted CPO-27-Mg for capture of CO2 under post-combustion and air filtering conditions: a combined experimental and computational study.

    Science.gov (United States)

    Bernini, M C; García Blanco, A A; Villarroel-Rocha, J; Fairen-Jimenez, D; Sapag, K; Ramirez-Pastor, A J; Narda, G E

    2015-11-21

    A computational and experimental screening of hypothetical and real compounds exhibiting different degrees of ethylenediamine grafted to the CPO-27-Mg or Mg-DOBDC skeleton is performed in order to determine the target composition that optimizes the CO2 adsorption properties under flue gas and air filtering conditions. On the basis of the [Mg2(dobdc)] formula, eighteen hypothetical models involving 15-100% of functionalization of the coordinatively unsaturated sites (CUS) were considered by means of Grand Canonical Monte Carlo simulations to evaluate the CO2 adsorption at 298 K. In addition, post-synthesis modification was applied to CPO-27-Mg leading to three kinds of samples exhibiting 15, 50, and 60% of CUS functionalization with ethylenediamine, named CPO-27-Mg-a, CPO-27-Mg-b and CPO-27-Mg-c. Compounds were characterized using elemental analysis, TGA, FTIR spectroscopy, PXRD and DSC. Finally, bare and functionalized CPO-27-Mg materials were evaluated using gas adsorption and microcalorimetry in the 0.001-1 bar range, which is pertinent for the mentioned applications. Valuable information related to design criteria for synthesis of tuned CO2 adsorbents is derived through this computational and experimental investigation.

  2. Simultaneous monitoring of PCB profiles in the urban air of Dalian, China with active and passive samplings

    Institute of Scientific and Technical Information of China (English)

    Qian Xu; Songtao Qin; Yan Li; Xiuhua Zhu; Bernhard Henkelmann; Karl-Werner Schramm; Jiping Chen; Yuwen Ni; Wei Wang; Gerd Pfister; Jun Mu

    2013-01-01

    The concentration of polychlorinated biphenyls (PCBs) in the urban air of Dalian,China was monitored from November 2009 to October 2010 with active high-volume sampler and semipermeable membrane device (SPMD) passive sampler.The concentration of PCBs (particle + gas) (ΣPCBs) ranged from 18.6 to 91.0 pg/m3,with an average of 50.9 pg/m3,and the most abundant dioxin-like PCB (DL-PCBs) was PCB118.The WHO-TEQ values of DL-PCBs were 3.6-22.1 fg/m3,with an average of 8.5 fg/m3,and PCB 126 was the maximum contributor to Σ TEQ.There was a much larger amount of PCBs in the gas phase than in the particulate phase.The dominant PCB components were lower and middle molecular weight PCBs.With increasing chlorination level,the concentration of the PCB congeners in the air decreased.The gas-particulate partitioning of PCBs was different for the four seasons.The gasparticulate partitioning coefficients (logKp) vs.subcooled liquid vapor pressures (logPL0) of PCBs had reasonable correlations for different sampling sites and seasons.The absorption mechanism contributed more to the gas-particulate partitioning process than adsorption.Correlation analysis of meteorological parameters with the concentration of PCBs was conducted using SPSS packages.The ambient temperature and atmospheric pressure were important factors influencing the concentration of PCBs in the air.The distribution pattern of the congeners of PCBs and the dominant contributors to DL-PCBs and TEQ in active samples and SPMDs passive samples were similar.SPMD mainly sequestrated gas phase PCBs.

  3. Biochemical and cellular effects of electrophiles present in ambient air samples

    Science.gov (United States)

    Iwamoto, Noriko; Nishiyama, Akira; Eiguren-Fernandez, Arantzazu; Hinds, William; Kumagai, Yoshito; Froines, John R.; Cho, Arthur K.; Shinyashiki, Masaru

    2010-04-01

    Ambient vapor-phase samples collected in Riverside, California had shown that both redox and electrophilic activity were present, with the vapor phase containing higher levels of electrophiles than the particle phase. In this study, the biochemical effects of the vapor-phase electrophiles were examined using the purified thiol proteins, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), protein tyrosine phosphatase 1B (PTP1B) and KELCH-1 like ECH-associated protein 1 (Keap1). The results demonstrated that the thiol proteins were inactivated by the vapor-phase samples through covalent modifications. Next, two cellular responses, epidermal growth factor receptor (EGFR)/mitogen-activated protein (MAP) kinase and NF-E2-related factor 2 (Nrf2), to the ambient vapor-phase samples were assessed in A549 and RAW 264.7 cell lines, respectively. The vapor-phase samples, at non-oxidative concentrations, increased phosphorylation of EGFR, which is negatively regulated by PTP1B, and its downstream MAP kinase, extracellular signal-regulated kinase (ERK)1/2. Activation of Nrf2, which requires Keap1 alkylation, and expression of its downstream proteins were also observed. The electrophilic compounds present in ambient vapor-phase were shown to modify cellular proteins through covalent modification and to activate diverse cellular responses that can lead to inflammatory and adaptive responses.

  4. Comprehensive software for the assessment of {sup 222}Rn and {sup 220}Rn decay products based on air sampling measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sima, Octavian [Physics Department, University of Bucharest, Bucharest-Magurele, P.O. Box MG-11, RO-077125 (Romania)], E-mail: octavian.sima@ik.fzk.de

    2009-05-15

    A computational tool dedicated to the measurement of {sup 222}Rn and {sup 220}Rn decay products by air sampling is presented. {alpha}- or {gamma}-spectrometry measurements, gross {alpha} or {beta} counting, as well as a combination of them are considered. Special attention is given to the evaluation of the uncertainty budget of the results. Besides typical applications in the analysis of experimental data, the software can be used for assessing the expected quality of a measurement protocol and for optimizing it, by generating and analyzing sets of realistic synthetic data.

  5. A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering

    Science.gov (United States)

    Shen, Chong; Li, Jie; Zhang, Xiaoming; Shi, Yunbo; Tang, Jun; Cao, Huiliang; Liu, Jun

    2016-01-01

    The different noise components in a dual-mass micro-electromechanical system (MEMS) gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN), electronic-thermal noise (ETN), flicker noise (FN) and Coriolis signal in-phase noise (IPN). The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD) and time-frequency peak filtering (TFPF). There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs) by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods. PMID:27258276

  6. A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering.

    Science.gov (United States)

    Shen, Chong; Li, Jie; Zhang, Xiaoming; Shi, Yunbo; Tang, Jun; Cao, Huiliang; Liu, Jun

    2016-01-01

    The different noise components in a dual-mass micro-electromechanical system (MEMS) gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN), electronic-thermal noise (ETN), flicker noise (FN) and Coriolis signal in-phase noise (IPN). The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD) and time-frequency peak filtering (TFPF). There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs) by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods. PMID:27258276

  7. Multilevel Mixture Kalman Filter

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2004-11-01

    Full Text Available The mixture Kalman filter is a general sequential Monte Carlo technique for conditional linear dynamic systems. It generates samples of some indicator variables recursively based on sequential importance sampling (SIS and integrates out the linear and Gaussian state variables conditioned on these indicators. Due to the marginalization process, the complexity of the mixture Kalman filter is quite high if the dimension of the indicator sampling space is high. In this paper, we address this difficulty by developing a new Monte Carlo sampling scheme, namely, the multilevel mixture Kalman filter. The basic idea is to make use of the multilevel or hierarchical structure of the space from which the indicator variables take values. That is, we draw samples in a multilevel fashion, beginning with sampling from the highest-level sampling space and then draw samples from the associate subspace of the newly drawn samples in a lower-level sampling space, until reaching the desired sampling space. Such a multilevel sampling scheme can be used in conjunction with the delayed estimation method, such as the delayed-sample method, resulting in delayed multilevel mixture Kalman filter. Examples in wireless communication, specifically the coherent and noncoherent 16-QAM over flat-fading channels, are provided to demonstrate the performance of the proposed multilevel mixture Kalman filter.

  8. Estimating individual exposure to 131I for radiation workers at radioisotope production using air sampling and smartphone techniques

    International Nuclear Information System (INIS)

    Indoor individual exposure at radioisotope production depends strongly on temporal concentration variation, contacting time and working location of radiation workers. To estimate personal exposure to indoor air polluted with 131I for the workers at radioisotope production, we had employed a low cost indoor model appropriate for their specific situation. In this model, time-microenvironment occupied by the workers was recorded by a smartphone sensitive motion software. Simultaneously, on the work days, indoor air in the three iodine production rooms was sampled by a portable air sampler coupled with activated carbon cartridges impregnated by TEDA. Then the low background gamma spectrometer was used to measure activity of the cartridges and the concentration of 131I in these rooms was calculated with the temporal resolution of one hour. By combining the hourly concentration with the high temporal resolution of activity patterns, we estimated the actual exposures for the group of workers producing radioisotopes in Nuclear Research Institute (Dalat) for the first four months of 2015. The highest daily average exposure was 410.2 Bq/m3 while the highest average exposure of the group was 147.2 Bq/m3. It showed an useful value for minimizing risks and estimating internal doses as well. This feasibility study may be applied for assessing personal exposure at radioisotope production, but also for many other indoor environments. (author)

  9. Determination of contamination in the air of reactor containment. Sampling and measuring techniques

    International Nuclear Information System (INIS)

    For the purposes of radiological safety work, the most important elements emerging from the primary circuit and responsible for contamination of the containment are noble gases due to fission or activation, iodine in different physico-chemical forms, and tritium. Sampling and measuring techniques used in studies conducted on in-service reactors (pressurized-water and fast reactor plants) are described, together with the results obtained. The method used for measuring the activity of iodine in its different forms (penetrating or non-penetrating) is to trap the iodine by means of a selective sampling device. The measurements are then made by gamma spectrometry. The technique used for measuring the noble gases is to enrich the carrier gas by means of cold traps, and then to make measurements with an ionization chamber or by gamma spectrometry. Tritium is trapped by bubbling through water and its activity measured with a liquid scintillation detector or proportional counter. (author)

  10. Development of automated preparation system for isotopocule analysis of N2O in various air samples

    Science.gov (United States)

    Toyoda, Sakae; Yoshida, Naohiro

    2016-05-01

    Nitrous oxide (N2O), an increasingly abundant greenhouse gas in the atmosphere, is the most important stratospheric ozone-depleting gas of this century. Natural abundance ratios of isotopocules of N2O, NNO molecules substituted with stable isotopes of nitrogen and oxygen, are a promising index of various sources or production pathways of N2O and of its sink or decomposition pathways. Several automated methods have been reported to improve the analytical precision for the isotopocule ratio of atmospheric N2O and to reduce the labor necessary for complicated sample preparation procedures related to mass spectrometric analysis. However, no method accommodates flask samples with limited volume or pressure. Here we present an automated preconcentration system which offers flexibility with respect to the available gas volume, pressure, and N2O concentration. The shortest processing time for a single analysis of typical atmospheric sample is 40 min. Precision values of isotopocule ratio analysis are < 0.1 ‰ for δ15Nbulk (average abundances of 14N15N16O and 15N14N16O relative to 14N14N16O), < 0.2 ‰ for δ18O (relative abundance of 14N14N18O), and < 0.5 ‰ for site preference (SP; difference between relative abundance of 14N15N16O and 15N14N16O). This precision is comparable to that of other automated systems, but better than that of our previously reported manual measurement system.

  11. Evaluation of a passive sampling system of CPVC for nitrogen dioxide in the air

    International Nuclear Information System (INIS)

    Passive diffusion tubes have been built to determine the concentration of NO2 in the air with poly tubes (vinyl chloride) chloride (CPVC). The performance has been evaluated during the 2008, through comparisons of their results with the results obtained, using the method modified Griess-Saltzman, recommended by the World Health Organization. The comparison results have shown good agreement between the two methodologies with respect to NO2 concentrations of 45-85 μg/m''3. Linear regression when used by minimum simple square and ranges test and Wilcoxon signs, no significant differences found between the results provided by both methods. Relative bias calculated in 7 comparisons has varied from -19,05% to 24,44% with an average of 5,76%. The results have indicated that the passive tubes overestimated the concentration of NO2; without however, this bias has not been higher than those reported by other authors. The precision the passive system has been in the field of 5,2% to 10,6%, measured in four tubes through the coefficient of variation, similar to reported by other researchers. (author)

  12. Microwave Filters

    OpenAIRE

    Zhou, Jiafeng

    2010-01-01

    The general theory of microwave filter design based on lumped-element circuit is described in this chapter. The lowpass prototype filters with Butterworth, Chebyshev and quasielliptic characteristics are synthesized, and the prototype filters are then transformed to bandpass filters by lowpass to bandpass frequency mapping. By using immitance inverters ( J - or K -inverters), the bandpass filters can be realized by the same type of resonators. One design example is given to verify the theory ...

  13. Multilevel ensemble Kalman filtering

    OpenAIRE

    Hoel, Håkon; Law, Kody J. H.; Tempone, Raul

    2015-01-01

    This work embeds a multilevel Monte Carlo (MLMC) sampling strategy into the Monte Carlo step of the ensemble Kalman filter (ENKF), thereby yielding a multilevel ensemble Kalman filter (MLENKF) which has provably superior asymptotic cost to a given accuracy level. The theoretical results are illustrated numerically.

  14. A Model Using Local Weather Data to Determine the Effective Sampling Volume for PCB Congeners Collected on Passive Air Samplers.

    Science.gov (United States)

    Herkert, Nicholas J; Martinez, Andres; Hornbuckle, Keri C

    2016-07-01

    We have developed and evaluated a mathematical model to determine the effective sampling volumes (Veff) of PCBs and similar compounds captured using polyurethane foam passive air samplers (PUF-PAS). We account for the variability in wind speed, air temperature, and equilibrium partitioning over the course of the deployment of the samplers. The model, provided as an annotated Matlab script, predicts the Veff as a function of physical-chemical properties of each compound and meteorology from the closest Integrated Surface Database (ISD) data set obtained through NOAA's National Centers for Environmental Information (NCEI). The model was developed to be user-friendly, only requiring basic Matlab knowledge. To illustrate the effectiveness of the model, we evaluated three independent data sets of airborne PCBs simultaneously collected using passive and active samplers: at sites in Chicago, Lancaster, UK, and Toronto, Canada. The model provides Veff values comparable to those using depuration compounds and calibration against active samplers, yielding an average congener specific concentration method ratio (active/passive) of 1.1 ± 1.2. We applied the model to PUF-PAS samples collected in Chicago and show that previous methods can underestimate concentrations of PCBs by up to 40%, especially for long deployments, deployments conducted under warming conditions, and compounds with log Koa values less than 8. PMID:26963482

  15. Detection of Bacillus anthracis DNA in complex soil and air samples using next-generation sequencing.

    Directory of Open Access Journals (Sweden)

    Nicholas A Be

    Full Text Available Bacillus anthracis is the potentially lethal etiologic agent of anthrax disease, and is a significant concern in the realm of biodefense. One of the cornerstones of an effective biodefense strategy is the ability to detect infectious agents with a high degree of sensitivity and specificity in the context of a complex sample background. The nature of the B. anthracis genome, however, renders specific detection difficult, due to close homology with B. cereus and B. thuringiensis. We therefore elected to determine the efficacy of next-generation sequencing analysis and microarrays for detection of B. anthracis in an environmental background. We applied next-generation sequencing to titrated genome copy numbers of B. anthracis in the presence of background nucleic acid extracted from aerosol and soil samples. We found next-generation sequencing to be capable of detecting as few as 10 genomic equivalents of B. anthracis DNA per nanogram of background nucleic acid. Detection was accomplished by mapping reads to either a defined subset of reference genomes or to the full GenBank database. Moreover, sequence data obtained from B. anthracis could be reliably distinguished from sequence data mapping to either B. cereus or B. thuringiensis. We also demonstrated the efficacy of a microbial census microarray in detecting B. anthracis in the same samples, representing a cost-effective and high-throughput approach, complementary to next-generation sequencing. Our results, in combination with the capacity of sequencing for providing insights into the genomic characteristics of complex and novel organisms, suggest that these platforms should be considered important components of a biosurveillance strategy.

  16. Glyphosate–rich air samples induce IL–33, TSLP and generate IL–13 dependent airway inflammation

    OpenAIRE

    Kumar, Sudhir; Khodoun, Marat; Kettleson, Eric M.; McKnight, Christopher; Reponen, Tiina; Grinshpun, Sergey A.; Adhikari, Atin

    2014-01-01

    Several low weight molecules have often been implicated in the induction of occupational asthma. Glyphosate, a small molecule herbicide, is widely used in the world. There is a controversy regarding a role of glyphosate in developing asthma and rhinitis among farmers, the mechanism of which is unexplored. The aim of this study was to explore the mechanisms of glyphosate induced pulmonary pathology by utilizing murine models and real environmental samples. C57BL/6, TLR4−/−, and IL-13−/− mice i...

  17. A study on elemental composition in epiphytic lichen samples used as bioindicator of air pollution in Sao Paulo city

    International Nuclear Information System (INIS)

    Studies on air pollution have intensified in recent years, due to the diversity of emissions and the effect caused to the health of populations. Consequently, several techniques have been investigated for air pollution evaluation and among them one that has gained considerable attention is that of biomonitoring. In this study chemical elemental levels in the atmosphere of Sao Paulo city were evaluated, by means of passive biomonitoring, using epiphytic Canoparmelia texana species, in order to compare between the results obtained in samples from different sites of Sao Paulo city and in a reference site of Ubatuba city, SP. Neutron activation analysis (NAA) procedure applied in the analyses consisted of irradiating aliquots of samples along with synthetic standards of elements in the nuclear reactor IEA-R1 for 16 hours under a thermal neutron flux of about 5.0 x 1012 n cm-2 s-1, followed by gamma ray spectrometry for the determination of As, Br, Ca, Co, Cr, Cs, Fe, K, La, Rb, Sc, Se and Zn. Results obtained in the analyses of lichens samples in replicates presented good reproducibility indicating homogeneity of the prepared samples. The precision and accuracy of the results were evaluated by the analyses of certified reference materials IAEA-336 Lichen and INCT-TL-1 Tea Leaves. Results obtained in the reference materials presented, in general, good precision, with relative standard deviations between 0.4 and 14.8% and good accuracy with relative errors between 0.2 and 8.7%. In Sao Paulo city, the lichens were collected in the following sites: Parque Dom Pedro II, Congonhas, Cidade Universitaria, Lapa, Mooca, Morumbi, Nossa Senhora do O, Parque Ibirapuera, Pinheiros, Santana, Santo Amaro and Taboao da Serra. Element concentrations found in lichens indicated a great variability depending on the sites where the samples were collected. The results obtained in the lichens submitted to the cluster analysis indicated three groups of sampling sites according to the chemical

  18. Summertime PAH assembly in Mediterranean air: the Herceg Novi sampling station as an example

    Directory of Open Access Journals (Sweden)

    VLADIMIR Z. JOVANOVIC

    2007-02-01

    Full Text Available The results of an analysis of the total suspended particles (TSP, total solvent organic extracts (TSOE, and polycyclic aromatic hydrocarbons (PAHs in aerosol samples collected from the atmosphere of Herceg Novi from 17th June to 15th September in 1998 and 1999 are presented. The TSP and TSOE concentrations were determined by the standard gr