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Sample records for air samplers pas

  1. Evaluating the PAS-SIM model using a passive air sampler calibration study for pesticides.

    PubMed

    Restrepo, Andrés Ramírez; Hayward, Stephen J; Armitage, James M; Wania, Frank

    2015-07-01

    The main objective of this study was to evaluate the performance of a model for simulating the uptake of various pesticides on passive air samplers (PAS). From 2006-2007 a series of PAS using XAD-resin were deployed at Egbert, a rural agricultural site in southern Ontario, Canada, to measure the uptake of pesticides for time periods ranging from two months to one year. A continuous increase in sequestered amounts was observed for most pesticides, except for trifluralin and pendimethalin, which could conceivably be subject to substantial degradation inside the sampler. Continuous low-volume active air samples taken during the same period, along with data on weather conditions, allowed for the simulation of the uptake of the pesticides using the model (PAS-SIM). The modelled accumulation of pesticides on the PAS over the deployment period was in good agreement with the experimental data in most cases (i.e., within a factor of two) providing insight into the uptake kinetics of this type of sampler in the field. Passive sampling rates (PSR, m(3) d(-1)) were determined from the empirical data generated for this study using three different methods and compared with the PSRs generated by the model. Overall, the PAS-SIM model, which is capable of accounting for the influence of temperature and wind variations on PSRs, provided reasonable results that range between the three empirical approaches employed and well-established literature values. Further evaluation and application of the PAS-SIM model to explore the potential spatial and temporal variability in PAS uptake kinetics is warranted, particularly for established monitoring sites where detailed meteorological data are more likely to be available.

  2. Comparison of two different passive air samplers (PUF-PAS versus SIP-PAS) to determine time-integrated average air concentration of volatile hydrophobic organic pollutants

    NASA Astrophysics Data System (ADS)

    Kim, Seung-Kyu; Park, Jong-Eun

    2014-06-01

    Despite remarkable achievements with r some chemicals, a field-measurement technique has not been advanced for volatile hydrophobic organic chemicals (HOCs) that are the subjects of international concern. This study assesses the applicability of passive air sampling (PAS) by comparing PUF-PAS and its modified SIP-PAS which was made by impregnating XAD-4 powder into PUF, overviewing the principles of PAS, screening sensitive parameters, and determining the uncertainty range of PAS-derived concentration. The PAS air sampling rate determined in this study, corrected by a co-deployed low-volume active air sampler (LAS) for neutral PFCs as model chemicals, was ˜1.2 m3 day-1. Our assessment shows that the improved sorption capacity in a SIP lengthens PAS deployment duration by expanding the linear uptake range and then enlarges the effective air sampling volume and detection frequency of chemicals at trace level. Consequently, volatile chemicals can be collected during sufficiently long times without reaching equilibrium when using SIP, while this is not possible for PUF. The most sensitive parameter to influence PAS-derived CA was an air-side mass transfer coefficient (kA), implying the necessity of spiking depuration chemicals (DCs) because this parameter is strongly related with meteorological conditions. Uncertainty in partition coefficients (KPSM-A or KOA) influences PAS-derived CA to a greater extent with regard to lower KPSM-A chemicals. Also, the PAS-derived CA has an uncertainty range of a half level to a 3-fold higher level of the calculated one. This work is expected to establish solid grounds for the improvement of field measurement technique of HOCs.

  3. Calibration of polydimethylsiloxane and XAD-Pocket passive air samplers (PAS) for measuring gas- and particle-phase SVOCs

    NASA Astrophysics Data System (ADS)

    Okeme, Joseph O.; Saini, Amandeep; Yang, Congqiao; Zhu, Jiping; Smedes, Foppe; Klánová, Jana; Diamond, Miriam L.

    2016-10-01

    Polydimethylsiloxane (PDMS) has seen wide use as the stationary phase of gas chromatographic columns, a passive sampler in water, and recently as a personal exposure sampler, while styrene divinyl-benzene copolymer (XAD) has been used extensively as a passive air sampler outdoors and indoors. We have introduced PDMS and XAD-Pocket as new indoor passive air samplers (PASs). The XAD-Pocket was designed to maximize the surface area-to-volume ratio of XAD and to minimize obstruction of air flow by the sampler housing. Methods were developed to expedite the use of these PASs for measuring phthalates, novel brominated flame-retardants (NFRs) and polybrominated diphenyl ethers (PBDEs) indoors. Sampling rates, Rs, (m3 day-1), were measured during a 7-week calibration study. Variability within and between analyte groups was not statistically significant. As a result, generic values of 0.8 ± 0.4 and 0.5 ± 0.3 m3 day-1 dm-2 are recommended for PDMS and XAD-Pocket for a 50-day deployment time, respectively. PDMS has a higher uptake rate and is easier to use than XAD-Pocket.

  4. Solid sorbent air sampler

    NASA Technical Reports Server (NTRS)

    Galen, T. J. (Inventor)

    1986-01-01

    A fluid sampler for collecting a plurality of discrete samples over separate time intervals is described. The sampler comprises a sample assembly having an inlet and a plurality of discreet sample tubes each of which has inlet and outlet sides. A multiport dual acting valve is provided in the sampler in order to sequentially pass air from the sample inlet into the selected sample tubes. The sample tubes extend longitudinally of the housing and are located about the outer periphery thereof so that upon removal of an enclosure cover, they are readily accessible for operation of the sampler in an analysis mode.

  5. Isokinetic air sampler

    DOEpatents

    Sehmel, George A.

    1979-01-01

    An isokinetic air sampler includes a filter, a holder for the filter, an air pump for drawing air through the filter at a fixed, predetermined rate, an inlet assembly for the sampler having an inlet opening therein of a size such that isokinetic air sampling is obtained at a particular wind speed, a closure for the inlet opening and means for simultaneously opening the closure and turning on the air pump when the wind speed is such that isokinetic air sampling is obtained. A system incorporating a plurality of such samplers provided with air pumps set to draw air through the filter at the same fixed, predetermined rate and having different inlet opening sizes for use at different wind speeds is included within the ambit of the present invention as is a method of sampling air to measure airborne concentrations of particulate pollutants as a function of wind speed.

  6. Breathing zone air sampler

    DOEpatents

    Tobin, John

    1989-01-01

    A sampling apparatus is provided which comprises a sampler for sampling air in the breathing zone of a wearer of the apparatus and a support for the sampler preferably in the form of a pair of eyeglasses. The sampler comprises a sampling assembly supported on the frame of the eyeglasses and including a pair of sample transport tubes which are suspended, in use, centrally of the frame so as to be disposed on opposite sides of the nose of the wearer and which each include an inlet therein that, in use, is disposed adjacent to a respective nostril of the nose of the wearer. A filter holder connected to sample transport tubes supports a removable filter for filtering out particulate material in the air sampled by the apparatus. The sample apparatus is connected to a pump for drawing air into the apparatus through the tube inlets so that the air passes through the filter.

  7. Field calibration of polyurethane foam (PUF) disk passive air samplers for PCBs and OC pesticides.

    PubMed

    Chaemfa, Chakra; Barber, Jonathan L; Gocht, Tilman; Harner, Tom; Holoubek, Ivan; Klanova, Jana; Jones, Kevin C

    2008-12-01

    Different passive air sampler (PAS) strategies have been developed for sampling in remote areas and for cost-effective simultaneous spatial mapping of POPs (persistent organic pollutants) over differing geographical scales. The polyurethane foam (PUF) disk-based PAS is probably the most widely used. In a PUF-based PAS, the PUF disk is generally mounted inside two stainless steel bowls to buffer the air flow to the disk and to shield it from precipitation and light. The field study described in this manuscript was conducted to: compare performance of 3 different designs of sampler; to further calibrate the sampler against the conventional active sampler; to derive more information on field-based uptake rates and equilibrium times of the samplers. Samplers were also deployed at different locations across the field site, and at different heights up a meteorological tower, to investigate the possible influence of sampler location. Samplers deployed <5m above ground, and not directly sheltered from the wind gave similar uptake rates. Small differences in dimensions between the 3 designs of passive sampler chamber had no discernable effect on accumulation rates, allowing comparison with previously published data.

  8. Characterization of two passive air samplers for per- and polyfluoroalkyl substances.

    PubMed

    Ahrens, Lutz; Harner, Tom; Shoeib, Mahiba; Koblizkova, Martina; Reiner, Eric J

    2013-12-17

    Two passive air sampler (PAS) media were characterized under field conditions for the measurement of per- and polyfluoroalkyl substances (PFASs) in the atmosphere. The PASs, consisting of polyurethane foam (PUF) and sorbent-impregnated PUF (SIP) disks, were deployed for over one year in parallel with high volume active air samplers (HV-AAS) and low volume active air samplers (LV-AAS). Samples were analyzed for perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkane sulfonic acids (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer methacrylates (FTMACs), fluorotelomer acrylates (FTACs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamidoethanols (FOSEs). Sampling rates and the passive sampler medium (PSM)-air partition coefficient (KPSM-A) were calculated for individual PFASs. Sampling rates were similar for PFASs present in the gas phase and particle phase, and the linear sampling rate of 4 m(-3) d(-1) is recommended for calculating effective air sample volumes in the SIP-PAS and PUF-PAS for PFASs except for the FOSAs and FOSEs in the PUF-PAS. SIP disks showed very good performance for all tested PFASs while PUF disks were suitable only for the PFSAs and their precursors. Experiments evaluating the suitability of different isotopically labeled fluorinated depuration compounds (DCs) revealed that (13)C8-perfluorooctanoic acid (PFOA) was suitable for the calculation of site-specific sampling rates. Ambient temperature was the dominant factor influencing the seasonal trend of PFASs.

  9. Evaluation of passive air sampler calibrations: Selection of sampling rates and implications for the measurement of persistent organic pollutants in air

    NASA Astrophysics Data System (ADS)

    Melymuk, Lisa; Robson, Matthew; Helm, Paul A.; Diamond, Miriam L.

    2011-04-01

    Polyurethane foam (PUF) passive air samplers (PAS) are a common and highly useful method of sampling persistent organic pollutants (POP) concentrations in air. PAS calibration is necessary to obtain reasonable and comparable semi-quantitative measures of air concentrations. Various methods are found in the literature concerning PAS calibration. 35 studies on PAS use and calibration are examined here, in conjunction with a study involving 10 PAS deployed concurrently in outdoor air with a low-volume air sampler in order to measure the sampling rates of PUF-PAS for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic musks (PCMs), and polycyclic aromatic hydrocarbons (PAHs). Based on this analysis it is recommended that (1) PAS should be assumed to represent bulk rather than gas-phase compound concentrations due to the sampling of particle-bound compounds, (2) calibration of PAS sampling rates is more accurately achieved using an active low-volume air sampler rather than depuration compounds since the former measures gas- and particle-phase compounds and does so continuously over the deployment period of the PAS, and (3) homolog-specific sampling rates based on KOA groupings be used in preference to compound/congener-specific or single sampling rates.

  10. CAM and stack air sampler design guide

    SciTech Connect

    Phillips, T.D.

    1994-05-13

    About 128 air samplers and CAMs presently in service to detect and document potential radioactive release from `H` and `F` area tank farm ventilation stacks are scheduled for replacement and/or upgrade by Projects S-5764, S-2081, S-3603, and S-4516. The seven CAMs scheduled to be upgraded by Project S-4516 during 1995 are expected to provide valuable experience for the three remaining projects. The attached document provides design guidance for the standardized High Level Waste air sampling system.

  11. Temporal variations of cyclic and linear volatile methylsiloxanes in the atmosphere using passive samplers and high-volume air samplers.

    PubMed

    Ahrens, Lutz; Harner, Tom; Shoeib, Mahiba

    2014-08-19

    Cyclic and linear volatile methylsiloxanes (cVMSs and lVMSs, respectively) were measured in ambient air over a period of over one year in Toronto, Canada. Air samples were collected using passive air samplers (PAS) consisting of sorbent-impregnated polyurethane foam (SIP) disks in parallel with high volume active air samplers (HV-AAS). The average difference between the SIP-PAS derived concentrations in air for the individual VMSs and those measured using HV-AAS was within a factor of 2. The air concentrations (HV-AAS) ranged 22-351 ng m(-3) and 1.3-15 ng m(-3) for ΣcVMSs (D3, D4, D5, D6) and ΣlVMSs (L3, L4, L5), respectively, with decamethylcyclopentasiloxane (D5) as the dominant compound (∼75% of the ΣVMSs). Air masses arriving from north to northwest (i.e., less populated areas) were significantly less contaminated with VMSs compared to air arriving from the south that are impacted by major urban and industrial areas in Canada and the U.S. (p < 0.05). In addition, air concentrations of ΣcVMSs were lower during major snowfall events (on average, 73 ng m(-3)) in comparison to the other sampling periods (121 ng m(-3)). Ambient temperature had a small influence on the seasonal trend of VMS concentrations in air, except for dodecamethylcyclohexasiloxane (D6), which was positively correlated with the ambient temperature (p < 0.001).

  12. Calibration of two passive air samplers for monitoring phthalates and brominated flame-retardants in indoor air.

    PubMed

    Saini, Amandeep; Okeme, Joseph O; Goosey, Emma; Diamond, Miriam L

    2015-10-01

    Two passive air samplers (PAS), polyurethane foam (PUF) disks and Sorbent Impregnated PUF (SIP) disks, were characterized for uptake of phthalates and brominated flame-retardants (BFRs) indoors using fully and partially sheltered housings. Based on calibration against an active low-volume air sampler for gas- and particle-phase compounds, we recommend generic sampling rates of 3.5±0.9 and 1.0±0.4 m(3)/day for partially and fully sheltered housing, respectively, which applies to gas-phase phthalates and BFRs as well as particle-phase DEHP (the later for the partially sheltered PAS). For phthalates, partially sheltered SIPs are recommended. Further, we recommend the use of partially sheltered PAS indoors and a deployment period of one month. The sampling rate for the partially sheltered PUF and SIP of 3.5±0.9 m(3)/day is indistinguishable from that reported for fully sheltered PAS deployed outdoors, indicating the role of the housing outdoors to minimize the effect of variable wind velocities on chemical uptake, versus the partially sheltered PAS deployed indoors to maximize chemical uptake where air flow rates are low.

  13. Influences of wind on the uptake of XAD passive air sampler in the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Wang, Xiaoping; Liu, Xiande

    2016-04-01

    The passive air sampler based on XAD-2 resin (XAD-PAS) is a useful tool for studying the long-range atmospheric transport of persistent organic pollutants (POPs) in the remote or high-altitude regions. Due to its opening bottom, the sampling processes of XAD-PAS was influenced by wind or air turbulence. By now, there were no studies focusing on the wind impact on the sampling rates (R values) in field. In this study, three sampling sites in the Tibetan Plateau, a high-altitude region with large range of wind speed (v), were chosen to calibrate XAD-PAS. In the low-wind regions, the R values fitted for the predicted values by ambient tempratrue (T) and air pressure (P). In the windy regions, not only T and P but also v impacted the R values, and an equation for estimating the R values was developed in the windy regions. Air turbulence may introduce the uncertainties of the R values, therefore, the improved type with spoilers on the bottom of XAD-PAS were designed to decrease the uncertainties. The observed R values of the improved XAD-PAS in field were good agreement with the predicted R values only by T^1.75/P, indicating that the improved XAD-PAS can decrease the influence of wind.

  14. Evaluation of the particle infiltration efficiency of three passive samplers and the PS-1 active air sampler

    NASA Astrophysics Data System (ADS)

    Markovic, Milos Z.; Prokop, Sebastian; Staebler, Ralf M.; Liggio, John; Harner, Tom

    2015-07-01

    The particle infiltration efficiencies (PIE) of three passive and one active air samplers were evaluated under field conditions. A wide-range particle spectrometer operating in the 250-4140 nm range was used to acquire highly temporally resolved particle-number and size distributions for the different samplers compared to ambient air. Overall, three of the four evaluated samplers were able to acquire a representative sample of ambient particles with PIEs of 91.5 ± 13.7% for the GAPS Network sampler, 103 ± 15.5% for the Lancaster University sampler, and 89.6 ± 13.4% for a conventional PS-1 high-volume active air sampler (Hi-Vol). Significantly (p = 0.05) lower PIE of 54 ± 8.0% was acquired for the passive sampler used under the MONET program. These findings inform the comparability and use of passive and active samplers for measuring particle-associated priority chemicals in air.

  15. Effect of wind on the chemical uptake kinetics of a passive air sampler.

    PubMed

    Zhang, Xianming; Brown, Trevor N; Ansari, Amer; Yeun, Beom; Kitaoka, Ken; Kondo, Akira; Lei, Ying D; Wania, Frank

    2013-07-16

    Passive air samplers (PASs) operate in different types of environment under various wind conditions, which may affect sampling rates and thus introduce uncertainty to PAS-derived air concentrations. To quantify the effect of wind speed and angle on the uptake in cylindrical PASs using XAD-resin as the sampling medium, we measured the uptake kinetics of polychlorinated biphenyls (PCBs) in XAD and of water in silica-gel, both under quasi wind-still condition and with lab-generated wind blowing toward the PASs at various speeds and angles. Passive sampling rates (PSRs) of PCBs under laboratory generated windy conditions were approximately 3-4 times higher than under wind-still indoor conditions. The rate of water uptake by silica-gel increased with wind speed, following a logarithmic function so that PSRs are more strongly influenced at lower wind speed. PSRs of both PCBs and water varied little with wind angle, which is consistent with computational fluid dynamic simulations showing that different angles of wind incidence cause only minor variations of air velocities within the cylindrical sampler housing. Because modifications of the design of the cylindrical PAS were not successful in eliminating the wind speed dependence of PSRs at low wind levels, indoor and outdoor deployments require different sets of PSRs. The effect of wind speed and angle on the PSRs of the cylindrical PAS are much smaller than what has been reported for the double-bowl polyurethane foam PAS. PSRs of the cylindrical XAD-PAS therefore tend to vary much less between sampling sites exposed to different wind conditions.

  16. Evaluation of portable air samplers for monitoring airborne culturable bacteria

    NASA Technical Reports Server (NTRS)

    Mehta, S. K.; Bell-Robinson, D. M.; Groves, T. O.; Stetzenbach, L. D.; Pierson, D. L.

    2000-01-01

    Airborne culturable bacteria were monitored at five locations (three in an office/laboratory building and two in a private residence) in a series of experiments designed to compare the efficiency of four air samplers: the Andersen two-stage, Burkard portable, RCS Plus, and SAS Super 90 samplers. A total of 280 samples was collected. The four samplers were operated simultaneously, each sampling 100 L of air with collection on trypticase soy agar. The data were corrected by applying positive hole conversion factors for the Burkard portable, Andersen two-stage, and SAS Super 90 air samplers, and were expressed as log10 values prior to statistical analysis by analysis of variance. The Burkard portable air sampler retrieved the highest number of airborne culturable bacteria at four of the five sampling sites, followed by the SAS Super 90 and the Andersen two-stage impactor. The number of bacteria retrieved by the RCS Plus was significantly less than those retrieved by the other samplers. Among the predominant bacterial genera retrieved by all samplers were Staphylococcus, Bacillus, Corynebacterium, Micrococcus, and Streptococcus.

  17. Evaluation of two passive samplers for the analysis of organophosphate esters in the ambient air.

    PubMed

    Liu, Ruirui; Lin, Yongfeng; Liu, Runzeng; Hu, Fanbao; Ruan, Ting; Jiang, Guibin

    2016-01-15

    Both polyurethane foam (PUF) and sorbent-impregnated PUF (SIP) passive air sampling (PAS) methods were deployed and compared separately for the analysis of organophosphate esters (OPEs) in outdoor atmospheric environment. During an continuous period of 84 days, parallel samples were also collected by a high-volume active air sampler (HV-AAS) to assess the contamination levels and to calibrate uptake parameters of PAS. The total concentration of OPEs in both particulate and gaseous phases ranged from 1.50 to 5.64ng m(-3) in ambient air. Tris(2-chloroisopropyl) phosphate (TCPP) was the dominating analog, representing 78±9% of total OPE concentration. SIP-PAS showed longer linear-phase sampling period for TCPP, and accumulated more amount of the most volatile triethyl phosphate (TEP) and tributyl phosphate (TBP) homologues, while similar sorption performances of both PAS methods were found for most of the semi-volatile OPEs. Linear sampling rates in PUF-PAS and SIP-PAS disks were calculated for individual OPEs except for TEP and TBP, and the average uptake rates (3.3±1.1 and 3.5±1.7m(3)d(-1), respectively) were close to the acknowledged value (4m(-3)d(-1)) for persistent organic pollutants. Besides, isotopic labeled D15-Triphenyl phosphate (TPhP) could be used as a viable depuration compound to calculate site-specific sampling rates of OPEs, with a linear loss of up to ∼60% at the end of deployment time. PMID:26592578

  18. Evaluation of passive diffusion bag samplers, dialysis samplers, and nylon-screen samplers in selected wells at Andersen Air Force Base, Guam, March-April 2002

    USGS Publications Warehouse

    Vroblesky, Don A.; Joshi, Manish; Morrell, Jeff; Peterson, J.E.

    2003-01-01

    During March-April 2002, the U.S. Geological Survey, Earth Tech, and EA Engineering, Science, and Technology, Inc., in cooperation with the Air Force Center for Environmental Excellence, tested diffusion samplers at Andersen Air Force Base, Guam. Samplers were deployed in three wells at the Main Base and two wells at Marianas Bonins (MARBO) Annex as potential ground-water monitoring alternatives. Prior to sampler deployment, the wells were tested using a borehole flowmeter to characterize vertical flow within each well. Three types of diffusion samplers were tested: passive diffusion bag (PDB) samplers, dialysis samplers, and nylon-screen samplers. The primary volatile organic compounds (VOCs) tested in ground water at Andersen Air Force Base were trichloroethene and tetrachloroethene. In most comparisons, trichloroethene and tetrachloroethene concentrations in PDB samples closely matched concentrations in pumped samples. Exceptions were in wells where the pumping or ambient flow produced vertical translocation of water in a chemically stratified aquifer. In these wells, PDB samplers probably would be a viable alternative sampling method if they were placed at appropriate depths. In the remaining three test wells, the trichloroethene or tetrachloroethene concentrations obtained with the diffusion samplers closely matched the result from pumped sampling. Chloride concentrations in nylon-screen samplers were compared with chloride concentrations in dialysis and pumped samples to test inorganic-solute diffusion into the samplers across a range of concentrations. The test showed that the results from nylon-screen samplers might have underestimated chloride concentrations at depths with elevated chloride concentrations. The reason for the discrepancy in this investigation is unknown, but may be related to nylon-screen-mesh size, which was smaller than that used in previous investigations.

  19. A Model Using Local Weather Data to Determine the Effective Sampling Volume for PCB Congeners Collected on Passive Air Samplers.

    PubMed

    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.

  20. A Model Using Local Weather Data to Determine the Effective Sampling Volume for PCB Congeners Collected on Passive Air Samplers.

    PubMed

    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

  1. A Model Using Local Weather Data to Determine the Effective Sampling Volume for PCB Congeners Collected on Passive Air Samplers

    PubMed Central

    2016-01-01

    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

  2. Application of XAD-resin based passive air samplers to assess local (roadside) and regional patterns of persistent organic pollutants.

    PubMed

    Barthel, Paul; Thuens, Sabine; Shunthirasingham, Chubashini; Westgate, John N; Wania, Frank; Radke, Michael

    2012-07-01

    We used XAD-resin based passive air samplers (PAS) to measure atmospheric levels of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) at five ombrotrophic bogs in Eastern Canada. The aims of our study were to investigate the influence of local roads on contaminant levels in the bogs, to derive the regional pattern of atmospheric concentrations, and to assess the uncertainties of the method. Expanded uncertainties based on the duplicate PAS deployed at 24 sites were good for the PAHs, while the deployment period of approx. 100 days was too short to yield acceptable uncertainties for PCBs. The regional PAH distribution was in good agreement with the calculated source proximity of the sampled bogs. We conclude that XAD-resin based PAS deployed for comparatively short periods are well suited for measuring atmospheric concentrations of volatile PAHs, while in remote regions longer deployment is necessary for less volatile PAHs and for PCBs. PMID:22516712

  3. An Inexpensive Remote Sequential Air Sampler

    ERIC Educational Resources Information Center

    Griffith, George A.; And Others

    1974-01-01

    Describes a remote air sampling device constructed of a number of spring loaded syringes which are released sequentially by the motion of a rotary mechanical timer. The unit can take accurate samples automatically and contain the samples without leakage for periods up to 18 hours in an outdoor environment. (SLH)

  4. Passive Samplers for Investigations of Air Quality: Method Description, Implementation, and Comparison to Alternative Sampling Methods

    EPA Science Inventory

    This Paper covers the basics of passive sampler design, compares passive samplers to conventional methods of air sampling, and discusses considerations when implementing a passive sampling program. The Paper also discusses field sampling and sample analysis considerations to ensu...

  5. Application of semipermeable membrane devices (SPMDs) as passive air samplers

    USGS Publications Warehouse

    Petty, Jimmie D.; Huckins, James N.; Zajicek, James L.

    1993-01-01

    The semipermeable membrane device (SPMD), consisting of a neutral lipid (triolein) enclosed in polyethylene layflat tubing, is demonstrated to be a highly efficient passive air sampler. These devices readily sequester lipophilic organic contaminants from the vapor phase. Specifically, the SPMDs are shown to concentrate polychlorinated biphenyl (PCB) residues from a laboratory atmosphere in a linear manner through 28 days. Under the conditions of this study, a three device composite (1.4 g triolein) extracted PCB residues from ≈ 7 m3 of air per day.

  6. Assessing levels and seasonal variations of current-use pesticides (CUPs) in the Tuscan atmosphere, Italy, using polyurethane foam disks (PUF) passive air samplers.

    PubMed

    Estellano, Victor H; Pozo, Karla; Efstathiou, Christos; Pozo, Katerine; Corsolini, Simonetta; Focardi, Silvano

    2015-10-01

    Polyurethane foam disks (PUF) passive air samplers (PAS) were deployed over 4 sampling periods of 3-5-months (≥ 1 year) at ten urban and rural locations throughout the Tuscany Region. The purpose was to assess the occurrence and seasonal variations of ten current-use pesticides (CUPs). PUF disk extracts were analyzed using GC-MS. The organophosphates insecticides; chlorpyrifos (3-580 pg m(-3)) and chlorpyrifos-methyl (below detection limit - to 570 pg m(-3)) presented the highest levels in air, and showed seasonal fluctuation coinciding with the growing seasons. The relative proportion urban/(urban + rural) ranged from 0.4 to 0.7 showing no differences between urban and rural concentrations. Air back trajectories analysis showed air masses passing over agricultural fields and potentially enhancing the drift of pesticides into the urban sites. This study represents the first information regarding CUPs in the atmosphere of Tuscany region using PAS-PUF disk.

  7. A source of PCB contamination in modified high-volume air samplers

    SciTech Connect

    Basu, I.; O'Dell, J.M.; Arnold, K.; Hites, R.A.

    2000-02-01

    Modified Anderson High Volume (Hi-Vol) air samplers are widely used for the collection of semi-volatile organic compounds (such as PCBs) from air. The foam gasket near the main air flow path in these samplers can become contaminated with PCBs if the sampler or the gasket is stored at a location with high indoor air PCB levels. Once the gasket is contaminated, it releases PCBs back into the air stream during sampling, and as a result, incorrectly high air PCB concentrations are measured. This paper presents data demonstrating this contamination problem using measurements from two Integrated Atmospheric Deposition Network sites: one at Sleeping Bear Dunes on Lake Michigan and the other at Point Petre on Lake Ontario. The authors recommend that these gaskets be replaced by Teflon tape and that the storage history of each sampler be carefully tracked.

  8. Development of an ambient air sampler that satisfies RF plant monitoring requirements

    SciTech Connect

    Nininger, R.C.; Pauley, B.J.

    1993-05-01

    EG&G Rocky Flats Plant (RFP) is developing a new ambient air particulate sampler to replace units that have been in service for about twenty years. The new sampler is required to operate at a flow rate approximately twice that of the existing samplers and admit particles as large as 70 micrometers aerodynamic diameter. The sampler provides two size fractions with separation at 10 micrometers. using a single stage impactor designed at RFP and carrying a Department of Energy (DOE) patent. The sampler is modular for easy servicing in the field and its operation can be checked via radiotelemetry. The sampler, designed to meet Environmental Protection Agency (EPA) requirements for PM-10 sampling, is currently being characterized in EPA`s laboratories at Research Triangle Park, North Carolina.

  9. Development of an ambient air sampler that satisfies RF plant monitoring requirements

    SciTech Connect

    Nininger, R.C.; Pauley, B.J.

    1993-01-01

    EG G Rocky Flats Plant (RFP) is developing a new ambient air particulate sampler to replace units that have been in service for about twenty years. The new sampler is required to operate at a flow rate approximately twice that of the existing samplers and admit particles as large as 70 micrometers aerodynamic diameter. The sampler provides two size fractions with separation at 10 micrometers. using a single stage impactor designed at RFP and carrying a Department of Energy (DOE) patent. The sampler is modular for easy servicing in the field and its operation can be checked via radiotelemetry. The sampler, designed to meet Environmental Protection Agency (EPA) requirements for PM-10 sampling, is currently being characterized in EPA's laboratories at Research Triangle Park, North Carolina.

  10. The Gillings Sampler--an electrostatic air sampler as an alternative method for aerosol in vitro exposure studies.

    PubMed

    Zavala, Jose; Lichtveld, Kim; Ebersviller, Seth; Carson, Johnny L; Walters, Glenn W; Jaspers, Ilona; Jeffries, Harvey E; Sexton, Kenneth G; Vizuete, William

    2014-09-01

    There is growing interest in studying the toxicity and health risk of exposure to multi-pollutant mixtures found in ambient air, and the U.S. Environmental Protection Agency (EPA) is moving towards setting standards for these types of mixtures. Additionally, the Health Effects Institute's strategic plan aims to develop and apply next-generation multi-pollutant approaches to understanding the health effects of air pollutants. There's increasing concern that conventional in vitro exposure methods are not adequate to meet EPA's strategic plan to demonstrate a direct link between air pollution and health effects. To meet the demand for new in vitro technology that better represents direct air-to-cell inhalation exposures, a new system that exposes cells at the air-liquid interface was developed. This new system, named the Gillings Sampler, is a modified two-stage electrostatic precipitator that provides a viable environment for cultured cells. Polystyrene latex spheres were used to determine deposition efficiencies (38-45%), while microscopy and imaging techniques were used to confirm uniform particle deposition. Negative control A549 cell exposures indicated the sampler can be operated for up to 4h without inducing any significant toxic effects on cells, as measured by lactate dehydrogenase (LDH) and interleukin-8 (IL-8). A novel positive aerosol control exposure method, consisting of a p-tolualdehyde (TOLALD) impregnated mineral oil aerosol (MOA), was developed to test this system. Exposures to the toxic MOA at a 1 ng/cm(2) dose of TOLALD yielded a reproducible 1.4 and 2-fold increase in LDH and IL-8 mRNA levels over controls. This new system is intended to be used as an alternative research tool for aerosol in vitro exposure studies. While further testing and optimization is still required to produce a "commercially ready" system, it serves as a stepping-stone in the development of cost-effective in vitro technology that can be made accessible to researchers in the

  11. A Passive Sampler for Determination of Nitrogen Dioxide in Ambient Air

    NASA Astrophysics Data System (ADS)

    Xiao, Dan; Lin, Lianzhi; Yuan, Hongyan; Choi, Martin M. F.; Chan, Winghong

    2005-08-01

    This article describes the use of a passive sampler for detecting and collecting nitrogen dioxide, NO 2 , in ambient air. This device is based on microporous PTFE membranes that allow air samples to diffuse through and subsequently react with an absorbing reagent solution. The absorbance value of this reagent is proportional to the NO 2 concentration in ambient air. It has been successfully applied to determine the NO 2 concentrations in various sampling sites. The sampler is simple, lightweight, and inexpensive. The experiments are suitable for college students in analytical chemistry and environmental studies.

  12. On the efficiency and correction of vertically oriented blunt bioaerosol samplers in moving air

    NASA Astrophysics Data System (ADS)

    Michel, Dominik; Rotach, Mathias W.; Gehrig, Regula; Vogt, Roland

    2012-11-01

    The aspiration efficiency of vertical and wind-oriented Air-O-Cell samplers was investigated in a field study using the pollen of hazel, sweet chestnut and birch. Collected pollen numbers were compared to measurements of a Hirst-type Burkard spore trap. The discrepancy between pollen counts is substantial in the case of vertical orientation. The results indicate a strong influence of wind velocity and inlet orientation relative to the freestream on the aspiration efficiency. Various studies reported on inertial effects on aerosol motion as function of wind velocity. The measurements were compared to a physically based model for the limited case of vertical blunt samplers. Additionally, a simple linear model based on pollen counts and wind velocity was developed. Both correction models notably reduce the error of vertically oriented samplers, whereas only the physically based model can be used on independent datasets. The study also addressed the precision error of the instruments used, which was substantial for both sampler types.

  13. Arduino-based control system for measuring ammonia in air using conditionally-deployed diffusive samplers

    NASA Astrophysics Data System (ADS)

    Ham, J. M.; Williams, C.; Shonkwiler, K. B.

    2012-12-01

    Arduino microcontrollers, wireless modules, and other low-cost hardware were used to develop a new type of air sampler for monitoring ammonia at strong areal sources like dairies, cattle feedlots, and waste treatment facilities. Ammonia was sampled at multiple locations on the periphery of an operation using Radiello diffusive passive samplers (Cod. RAD168- and RAD1201-Sigma-Aldrich). However, the samplers were not continuously exposed to the air. Instead, each sampling station included two diffusive samplers housed in specialized tubes that sealed the cartridges from the atmosphere. If a user-defined set of wind and weather conditions were met, the Radiellos were deployed into the air using a micro linear actuator. Each station was solar-powered and controlled by Arduinos that were linked to a central weather station using Xbee wireless modules (Digi International Inc.). The Arduinos also measured the total time of exposure using hall-effect sensors to verify the position of the cartridge (i.e., deployed or retracted). The decision to expose or retract the samplers was made every five minutes based on wind direction, wind speed, and time of day. Typically, the diffusive samplers were replaced with fresh cartridges every two weeks and the used samplers were analyzed in the laboratory using ion chromatography. Initial studies were conducted at a commercial dairy in northern Colorado. Ammonia emissions along the Front Range of Colorado can be transported into the mountains where atmospheric deposition of nitrogen can impact alpine ecosystems. Therefore, low-cost air quality monitoring equipment is needed that can be widely deployed in the region. Initial work at the dairy showed that ammonia concentrations ranged between 600 to 1200 ppb during the summer; the highest concentrations were downwind of a large anaerobic lagoon. Time-averaged ammonia concentrations were also used to approximate emissions using inverse dispersion models. This methodology provides a

  14. The Gillings Sampler – An Electrostatic Air Sampler as an Alternative Method for Aerosol In Vitro Exposure Studies

    PubMed Central

    Zavala, Jose; Lichtveld, Kim; Ebersviller, Seth; Carson, Johnny L.; Walters, Glenn W.; Jaspers, Ilona; Jeffries, Harvey E.; Sexton, Kenneth G.; Vizuete, William

    2014-01-01

    There is growing interest in studying the toxicity and health risk of exposure to multi-pollutant mixtures found in ambient air, and the U.S. Environmental Protection Agency (EPA) is moving towards setting standards for these types of mixtures. Additionally, the Health Effects Institute's strategic plan aims to develop and apply next-generation multi-pollutant approaches to understanding the health effects of air pollutants. There's increasing concern that conventional in vitro exposure methods are not adequate to meet EPA's strategic plan to demonstrate a direct link between air pollution and health effects. To meet the demand for new in vitro technology that better represents direct air-to-cell inhalation exposures, a new system that exposes cells at the air-liquid interface was developed. This new system, named the Gillings Sampler, is a modified two-stage electrostatic precipitator that provides a viable environment for cultured cells. Polystyrene latex spheres were used to determine deposition efficiencies (38-45%), while microscopy and imaging techniques were used to confirm uniform particle deposition. Negative control A549 cell exposures indicated the sampler can be operated for up to 4 hours without inducing any significant toxic effects on cells, as measured by lactate dehydrogenase (LDH) and interleukin-8 (IL-8). A novel positive aerosol control exposure method, consisting of a p-tolualdehyde (TOLALD) impregnated mineral oil aerosol (MOA), was developed to test this system. Exposures to the toxic MOA at a 1 ng/cm2 dose of TOLALD yielded a reproducible 1.4 and 2 fold increase in LDH and IL-8 mRNA levels over controls. This new system is intended to be used as an alternative research tool for aerosol in vitro exposure studies. While further testing and optimization is still required to produce a “commercially ready” system, it serves as a stepping-stone in the development of cost-effective in vitro technology that can be made accessible to researchers

  15. Passive samplers and community science in regional air quality measurement, education and communication.

    PubMed

    DeForest Hauser, Cindy; Buckley, Alexandra; Porter, Juliana

    2015-08-01

    Charlotte, in Mecklenburg County, North Carolina, was ranked in the top ten cities with the worst air quality for ozone in the United States by the American Lung Association from 2009 to 2011. Nearby counties that may experience similar air quality do not have state or county monitors. This study utilized NOx and ozone Ogawa passive samplers and community scientists to monitor air quality in five counties surrounding Charlotte and increase public engagement in air quality issues. Community scientists deployed samplers weekly at a residential site within each county. Samples were analyzed using spectrophotometry and ion chromatography. Elevated NOx concentrations were observed in four of the five counties relative to those with existing monitors. Ozone concentrations showed little county to county variation, except Iredell and Cabarrus which had higher concentrations than Rowan. Community involvement in this work led to an increase in local dissemination of the results, thus increasing air quality awareness. PMID:25556581

  16. Operating High-Volume Air Samplers. Module 3. Vocational Education Training in Environmental Health Sciences.

    ERIC Educational Resources Information Center

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on operating high-volume air samplers. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) disassembling the high-volume…

  17. Validation of a flow-through sampler for pesticides and polybrominated diphenyl ethers in air

    NASA Astrophysics Data System (ADS)

    Xiao, Hang; Hung, Hayley; Lei, Ying Duan; Wania, Frank

    At locations without access to the electrical grid, a flow-through sampler (FTS) collects large volumes of air for the analysis of semi-volatile organic compounds (SVOCs). To test its performance under field conditions, an FTS and a traditional pumped high volume air sampler, both using polyurethane foam (PUF) as sampling medium, were co-deployed at the campus of the University of Toronto Scarborough from August 2006 to June 2007. Polybrominated diphenyl ethers (PBDEs) and various pesticides were quantified in the samples taken by both samplers to test the FTS's applicability to relatively non-volatile and slightly polar SVOCs. Air concentrations in samples taken with the FTS over five 2-week periods compare favourably with the average of the concentrations in several 24-h active high volume samples taken during the same period. In particular, time trends, temperature dependence relationships, and isomer ratios show a reasonable agreement between the two sampling techniques. An empirical linear solvation energy relationship for predicting the apparent theoretical plate number of the PUF assembly used in the FTS illustrates the effect of chemical properties, as well as temperature and wind speed, on sampling efficiency. In the absence of electrical power, the FTS can collect SVOCs from large air volumes as reliably and quantitatively as traditional HiVol samplers, although without separating gas and particle phase.

  18. A Passive Sampler for Determination of Nitrogen Dioxide in Ambient Air

    ERIC Educational Resources Information Center

    Xiao, Dan; Lin, Lianzhi; Yuan, Hongyan; Choi, Martin M. F.; Chan, Winghong

    2005-01-01

    A passive sampler that provides a convenient, simple, and fast method for nitrogen dioxide determination is proposed. The experiment can be modified for determinations of other air pollutants like formaldehyde and sulfur dioxide for hands-on experience for students studying environmental pollution problems.

  19. Evaluation of physical sampling efficiency for cyclone-based personal bioaerosol samplers in moving air environments.

    PubMed

    Su, Wei-Chung; Tolchinsky, Alexander D; Chen, Bean T; Sigaev, Vladimir I; Cheng, Yung Sung

    2012-09-01

    The need to determine occupational exposure to bioaerosols has notably increased in the past decade, especially for microbiology-related workplaces and laboratories. Recently, two new cyclone-based personal bioaerosol samplers were developed by the National Institute for Occupational Safety and Health (NIOSH) in the USA and the Research Center for Toxicology and Hygienic Regulation of Biopreparations (RCT & HRB) in Russia to monitor bioaerosol exposure in the workplace. Here, a series of wind tunnel experiments were carried out to evaluate the physical sampling performance of these two samplers in moving air conditions, which could provide information for personal biological monitoring in a moving air environment. The experiments were conducted in a small wind tunnel facility using three wind speeds (0.5, 1.0 and 2.0 m s(-1)) and three sampling orientations (0°, 90°, and 180°) with respect to the wind direction. Monodispersed particles ranging from 0.5 to 10 μm were employed as the test aerosols. The evaluation of the physical sampling performance was focused on the aspiration efficiency and capture efficiency of the two samplers. The test results showed that the orientation-averaged aspiration efficiencies of the two samplers closely agreed with the American Conference of Governmental Industrial Hygienists (ACGIH) inhalable convention within the particle sizes used in the evaluation tests, and the effect of the wind speed on the aspiration efficiency was found negligible. The capture efficiencies of these two samplers ranged from 70% to 80%. These data offer important information on the insight into the physical sampling characteristics of the two test samplers.

  20. Plant leaves as indoor air passive samplers for volatile organic compounds (VOCs).

    PubMed

    Wetzel, Todd A; Doucette, William J

    2015-03-01

    Volatile organic compounds (VOCs) enter indoor environments through internal and external sources. Indoor air concentrations of VOCs vary greatly but are generally higher than outdoors. Plants have been promoted as indoor air purifiers for decades, but reports of their effectiveness differ. However, while air-purifying applications may be questionable, the waxy cuticle coating on leaves may provide a simple, cost-effective approach to sampling indoor air for VOCs. To investigate the potential use of plants as indoor air VOC samplers, a static headspace approach was used to examine the relationship between leaf and air concentrations, leaf lipid contents and octanol-air partition coefficients (Koa) for six VOCs and four plant species. The relationship between leaf and air concentrations was further examined in an actual residence after the introduction of several chlorinated VOC emission sources. Leaf-air concentration factors (LACFs), calculated from linear regressions of the laboratory headspace data, were found to increase as the solvent extractable leaf lipid content and Koa value of the VOC increased. In the studies conducted in the residence, leaf concentrations paralleled the changing air concentrations, indicating a relatively rapid air to leaf VOC exchange. Overall, the data from the laboratory and residential studies illustrate the potential for plant leaves to be used as cost effective, real-time indoor air VOC samplers.

  1. Evaluation of passive diffusion bag and dialysis samplers in selected wells at Hickam Air Force Base, Hawaii, July 2001

    USGS Publications Warehouse

    Vroblesky, Don A.; Pravecek, Tasha

    2002-01-01

    Field comparisons of chemical concentrations obtained from dialysis samplers, passive diffusion bag samplers, and low-flow samplers showed generally close agreement in most of the 13 wells tested during July 2001 at Hickam Air Force Base, Hawaii. The data for chloride, sulfate, iron, alkalinity, arsenic, and methane appear to show that the dialysis samplers are capable of accurately collecting a passive sample for these constituents. In general, the comparisons of volatile organic compound concentrations showed a relatively close correspondence between the two different types of diffusion samples and between the diffusion samples and the low-flow samples collected in most wells. Divergence appears to have resulted primarily from the pumping method, either producing a mixed sample or water not characteristic of aquifer water moving through the borehole under ambient conditions. The fact that alkalinity was not detected in the passive diffusion bag samplers, highly alkaline waters without volatilization loss from effervescence, which can occur when a sample is acidified for preservation. Both dialysis and passive diffusion bag samplers are relatively inexpensive and can be deployed rapidly and easily. Passive diffusion bag samplers are intended for sampling volatile organic compounds only, but dialysis samplers can be used to sample both volatile organic compounds and inorganic solutes. Regenerated cellulose dialysis samplers, however, are subject to biodegradation and probably should be deployed no sooner than 2 weeks prior to recovery. 1 U.S. Geological Survey, Columbia, South Carolina. 2 Air Florce Center for Environmental Excellence, San Antionio, Texas.

  2. Development and testing of a portable wind sensitive directional air sampler

    NASA Technical Reports Server (NTRS)

    Deyo, J.; Toma, J.; King, R. B.

    1975-01-01

    A portable wind sensitive directional air sampler was developed as part of an air pollution source identification system. The system is designed to identify sources of air pollution based on the directional collection of field air samples and their analysis for TSP and trace element characteristics. Sources can be identified by analyzing the data on the basis of pattern recognition concepts. The unit, designated Air Scout, receives wind direction signals from an associated wind vane. Air samples are collected on filter slides using a standard high volume air sampler drawing air through a porting arrangement which tracks the wind direction and permits collection of discrete samples. A preset timer controls the length of time each filter is in the sampling position. At the conclusion of the sampling period a new filter is automatically moved into sampling position displacing the previous filter to a storage compartment. Thus the Air Scout may be set up at a field location, loaded with up to 12 filter slides, and left to acquire air samples automatically, according to the wind, at any timer interval desired from 1 to 30 hours.

  3. PASSIVE/DIFFUSIVE SAMPLERS FOR PESTICIDES IN RESIDENTIAL INDOOR AIR

    EPA Science Inventory

    Pesticides applied indoors vaporize from treated surfaces (e.g., carpets and baseboards) resulting in elevated air concentrations that may persist for long periods after applications. Estimating long-term respiratory exposures to pesticide vapors in residential indoor environme...

  4. Particle impactor assembly for size selective high volume air sampler

    DOEpatents

    Langer, Gerhard

    1988-08-16

    Air containing entrained particulate matter is directed through a plurality of parallel, narrow, vertically oriented impactor slots of an inlet element toward an adjacently located, relatively large, dust impaction surface preferably covered with an adhesive material. The air flow turns over the impaction surface, leaving behind the relatively larger particles according to the human thoracic separation system and passes through two elongate exhaust apertures defining the outer bounds of the impaction collection surface to pass through divergent passages which slow down and distribute the air flow, with entrained smaller particles, over a fine filter element that separates the fine particles from the air. The elongate exhaust apertures defining the impaction collection surface are spaced apart by a distance greater than the lengths of elongate impactor slots in the inlet element and are oriented to be normal thereto. By appropriate selection of dimensions and the number of impactor slots air flow through the inlet element is provided a nonuniform velocity distribution with the lower velocities being obtained near the center of the impactor slots, in order to separate out particles larger than a certain predetermined size on the impaction collection surface. The impaction collection surface, even in a moderately sized apparatus, is thus relatively large and permits the prolonged sampling of air for periods extending to four weeks.

  5. Step-Scan T-Cell Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) for Monitoring Environmental Air Pollutants

    NASA Astrophysics Data System (ADS)

    Liu, Lixian; Mandelis, Andreas; Melnikov, Alexander; Michaelian, Kirk; Huan, Huiting; Haisch, Christoph

    2016-07-01

    Air pollutants have adverse effects on the Earth's climate system. There is an urgent need for cost-effective devices capable of recognizing and detecting various ambient pollutants. An FTIR photoacoustic spectroscopy (FTIR-PAS) method based on a commercial FTIR spectrometer developed for air contamination monitoring will be presented. A resonant T-cell was determined to be the most appropriate resonator in view of the low-frequency requirement and space limitations in the sample compartment. Step-scan FTIR-PAS theory for regular cylinder resonator has been described as a reference for prediction of T-cell vibration principles. Both simulated amplitude and phase responses of the T-cell show good agreement with measurement data Carbon dioxide IR absorption spectra were used to demonstrate the capacity of the FTIR-PAS method to detect ambient pollutants. The theoretical detection limit for carbon dioxide was found to be 4 ppmv. A linear response to carbon dioxide concentration was found in the range from 2500 ppmv to 5000 ppmv. The results indicate that it is possible to use step-scan FTIR-PAS with a T-cell as a quantitative method for analysis of ambient contaminants.

  6. Stationary source sampling report: Ambient and source volatile organic compound testing, Production air stripper unit 1 (PASU-1) and pilot air stripper (PAS)

    SciTech Connect

    Not Available

    1984-09-05

    Tests were performed to measure the ambient concentrations of perchloroethylene, trichloroethylene, and 1,1,1-trichloroethane in the A/M area and to determine, for compliance purposes, the emissions and concentrations of those compounds issued from the Production Air Stripper Unit 1 (PASU-1) column and from the Pilot Air Stripper (PAS) column.

  7. Determination of toxic congeners of 17 PCDDs/PCDFs and 12 dl-PCBs using polyurethane foam passive air samplers in ten cities around Seoul.

    PubMed

    Yoonki, Min; Jongwon, Heo; Meehye, Lee

    2014-09-01

    Twenty-nine toxic congeners including 17 polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were determined using passive air samplers (PAS) at ten satellite cities of Seoul for two years. Chemical analysis was done by high resolution gas chromatography (HRGC) coupled with high resolution mass spectrometry (HRMS). The ten monitoring sites represent urban-residential, industrial, urban-rural mixed, and rural types of regions in Gyeonggi Province, Republic of Korea. The concentrations of PCDDs/PCDFs and dioxin-like PCBs ranged from 0.59 pg·day(-1) to 29.7 pg·day(-1) and from 3.44 pg·day(-1) to 99.7 pg·day(-1), respectively with the highest values at industrial areas. The relative abundance of more toxic congeners (tetra- and penta-chlorinated PCDDs/PCDFs) was the highest in urban-rural mixed group despite the less emission sources than industrial group. It implies that this group was under the influence of fugitive emissions that have not yet been identified or regulated. This study reports the first attempt of atmospheric PCDDs/PCDFs and dl-PCB measurements with PAS in the monitoring network of Korea, which highlights the efficacy of PAS in continuous and long-term monitoring of those species particularly at regions that could easily slip out of environmental governance or of low accessibility to monitoring.

  8. Polyurethane foam (PUF) disks passive air samplers: wind effect on sampling rates.

    PubMed

    Tuduri, Ludovic; Harner, Tom; Hung, Hayley

    2006-11-01

    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 approximately 4.5-14.6 m3 d-1 and then increased sharply to approximately 42 m3 d-1 at approximately 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.

  9. Extended duration orbiter medical project Microbial Air Sampler (STS-50/USML-1)

    NASA Technical Reports Server (NTRS)

    Pierson, Duane L.; Boettcher, Sheila W.

    1994-01-01

    The Microbial Air Sampler was used on mission days 1, 7, and 13 in the Spacelab during STS-50/USML-1. Microbial air samples were collected using two types of media strips containing agar (Rose Bengal for yeast and molds, TSA for bacteria). The bacterial level found on day 1 was lower than experienced on previous Spacelab missions. A high level of fungi was present on day 1, however subsequent samples on days 7 and 13 did not indicate fungal growth. Bacterial growth was also minimized in this microgravity environment as the mission progressed. No pathogenic microorganisms were isolated, and the health risk from airborne microbes was minimal throughout the mission.

  10. Characterization of polymer coated glass as a passive air sampler for persistent organic pollutants.

    PubMed

    Harner, Tom; Farrar, Nick J; Shoeib, Mahiba; Jones, Kevin C; Gobas, Frank A P C

    2003-06-01

    The use of thin-film polymer-coated glass surfaces or POGs as passive air samplers was investigated during an uptake experiment in an indoor environment with high levels of gas-phase polychlorinated biphenyls (PCBs). POGs consisted of a micron thick layer of ethylene vinyl acetate (EVA) coated onto glass cylinders. The uptake was initially linear with time and governed by the air-side mass transfer coefficient and surface area of the sampler. This was followed by a curvilinear region and finally a constant phase when equilibrium was established between air and EVA. The high surface area-to-volume ratio of the POGs allowed rapid equilibrium with gas-phase PCBs; equilibration times were on the order of hours for the low molecular weight congeners. The equilibrium concentration was dependent on the EVA-air partition coefficient, K(EVA-A), which was shown to be very well correlated to the octanol-air partition coefficient, K(OA). When POGs of varying thickness were equilibrated with air, the amount of PCB accumulated increased with increasing thickness of the EVA, indicating that uptake was by absorption into the entire polymer matrix. A wind field of 4 m s(-1) resulted in an increased uptake rate by a factor of approximately six compared to uptake in relatively still air. This wind speed effect was diminished, however, when POGs were housed in deployment chambers consisting of inverted stainless steel bowls. Relationships based on the air-side mass transfer coefficient and K(EVA-A) were developed for PCBs that describe the entire uptake profile and allow air concentrations to be determined from the amount of chemical accumulated in the POG. It is believed that these relationships are also valid when POGs are used to detect other classes of persistent organic pollutants. PMID:12831034

  11. Characterization of polymer coated glass as a passive air sampler for persistent organic pollutants.

    PubMed

    Harner, Tom; Farrar, Nick J; Shoeib, Mahiba; Jones, Kevin C; Gobas, Frank A P C

    2003-06-01

    The use of thin-film polymer-coated glass surfaces or POGs as passive air samplers was investigated during an uptake experiment in an indoor environment with high levels of gas-phase polychlorinated biphenyls (PCBs). POGs consisted of a micron thick layer of ethylene vinyl acetate (EVA) coated onto glass cylinders. The uptake was initially linear with time and governed by the air-side mass transfer coefficient and surface area of the sampler. This was followed by a curvilinear region and finally a constant phase when equilibrium was established between air and EVA. The high surface area-to-volume ratio of the POGs allowed rapid equilibrium with gas-phase PCBs; equilibration times were on the order of hours for the low molecular weight congeners. The equilibrium concentration was dependent on the EVA-air partition coefficient, K(EVA-A), which was shown to be very well correlated to the octanol-air partition coefficient, K(OA). When POGs of varying thickness were equilibrated with air, the amount of PCB accumulated increased with increasing thickness of the EVA, indicating that uptake was by absorption into the entire polymer matrix. A wind field of 4 m s(-1) resulted in an increased uptake rate by a factor of approximately six compared to uptake in relatively still air. This wind speed effect was diminished, however, when POGs were housed in deployment chambers consisting of inverted stainless steel bowls. Relationships based on the air-side mass transfer coefficient and K(EVA-A) were developed for PCBs that describe the entire uptake profile and allow air concentrations to be determined from the amount of chemical accumulated in the POG. It is believed that these relationships are also valid when POGs are used to detect other classes of persistent organic pollutants.

  12. Development and testing of a whole-air sampler for measurement of personal exposure to volatile organic compounds.

    PubMed

    Whitaker, D A; Fortmann, R C; Lindstrom, A B

    1995-01-01

    A small and relatively lightweight (3.35 kg) whole-air (canister) sampler that can be worn to monitor personal exposures to volatile organic compounds was developed and evaluated. The prototype personal whole-air sampler (PWAS) consists of a 1-l canister, a mass flow controller, two 1.3 amp hour batteries, a DC/DC converter, and an electronics module with a digital display for the sampling set point, actual flow rate, and battery voltage. The sampler (25.5 x 22.5 x 7.5 cm) fits into a laptop computer carrying case and is able to collect a 900 ml sample at a linear flow rate over 12-16 hours. Laboratory tests demonstrated that the sample flow rate was not affected by temperature or the activity of the person wearing the sampler. Recoveries of methylene chloride, chloroform, 1,1,1-trichloroethane, benzene, n-octane, o-xylene, n-decane, and p-dichlorobenzene averaged 89% or better for three final prototype samplers. Recoveries were slightly lower for vinyl chloride (74%) and n-dodecane (82%). The precision for the three prototypes was excellent during laboratory tests with the coefficient of variation (CV) < 10% for all the test compounds. Although the unit was designed for use as a personal whole-air sampling system, it can also be used as an extremely compact microenvironmental whole-air sampler.

  13. Evaluation and guidelines for using polyurethane foam (PUF) passive air samplers in double-dome chambers to assess semi-volatile organic compounds (SVOCs) in non-industrial indoor environments.

    PubMed

    Bohlin, Pernilla; Audy, Ondřej; Škrdlíková, Lenka; Kukučka, Petr; Vojta, Šimon; Přibylová, Petra; Prokeš, Roman; Čupr, Pavel; Klánová, Jana

    2014-11-01

    Indoor air pollution has been recognized as an important risk factor for human health, especially in areas where people tend to spend most of their time indoors. Many semi-volatile organic compounds (SVOCs) have primarily indoor sources and are present in orders of magnitude higher concentrations indoors than outdoors. Despite this, awareness of SVOCs in indoor air and assessment of the link between indoor concentrations and human health have lagged behind those of outdoor air. This is partially related to challenges associated with indoor sampling of SVOCs. Passive air samplers (PASs), which are widely accepted in established outdoor air monitoring networks, have been used to fill the knowledge gaps on indoor SVOCs distribution. However, their applicability for indoor environments and the assessment of human health risks lack sufficient experimental data. To address this issue, we performed an indoor calibration study of polyurethane foam (PUF) PAS deployed in a double-dome chamber, covering both legacy and new SVOC classes. PUF-PAS and a continuous low-volume active air sampler (AAS) were co-deployed for a calibration period of twelve weeks. Based on the results from this evaluation, PUF-PAS in a double-bowl chamber is recommended for indoor sampling and health risk assessment of gas phase SVOCs, including novel brominated flame retardants (nBFR) providing sufficient exposure time is applied. Data for particle associated SVOCs suffered from significant uncertainties caused by low level of detection and low precision in this study. A more open chamber design for indoor studies may allow for higher sampling rates (RS) and better performance for the particle associated SVOCs. PMID:25274245

  14. Determination of phenolic compounds in air by using cyclodextrin-silica hybrid microporous composite samplers.

    PubMed

    Mauri-Aucejo, Adela R; Ponce-Català, Patricia; Belenguer-Sapiña, Carolina; Amorós, Pedro

    2015-03-01

    An analytical method for the determination of phenolic compounds in air samples based on the use of cyclodextrin-silica hybrid microporous composite samplers is proposed. The method allows the determination of phenol, guaiacol, cresol isomers, eugenol, 4-ethylphenol and 4-ethylguaiacol in workplaces according to the Norm UNE-EN 1076:2009 for active sampling. Therefore, the proposed method offers an alternative for the assessment of the occupational exposure to phenol and cresol isomers. The detection limits of the proposed method are lower than those for the NIOSH Method 2546. Storage time of samples almost reaches 44 days. Recovery values for phenol, guaiacol, o-cresol, m-cresol, p-cresol, 4-ethylguaiacol, eugenol and 4-ethylphenol are 109%, 99%, 102%, 94%, 94%, 91%, 95% and 102%, respectively with a coefficient of variation below 6%. The method has been applied to the assessment of exposure in different areas of a farm and regarding the quantification of these compounds in the vapors generated by burning incense sticks and an essential oil marketed as air fresheners. The acquired results are comparable with those provided from a reference method for a 95% of confidence level. The possible use of these samplers for the sampling of other toxic compounds such as phthalates is evaluated by qualitative analysis of extracts from incense sticks and essential oil samples.

  15. Design of a cryogenic sampler for gaseous hydrogen peroxide in ambient air

    SciTech Connect

    Chetty, T.; Karohl, D.

    1986-06-01

    This project designed and characterized the performance of a cryogenic sampler for gaseous H/sub 2/O/sub 2/. In preliminary experiments, 1-cm ID, 30 cm long U-tube in an acetone-dry ice bath achieved complete peroxide collection efficiency (E/sub H2O2/) from prepared air at 50% relative humidity (RH) and 1.5 ppbv H/sub 2/O/sub 2/. The performance of the U-tube sampler was further evaluated on the basis of water collection efficiency, a criterion which indicates the time required to collect a sample sufficiently large to analyze for H/sub 2/O/sub 2/. Water collection efficiency (E/sub H2O/) averaged 6.2 +- 2.9%, indicating good reproducibility but a far lower E than observed for H/sub 2/O/sub 2/, suggesting that the mechanisms for water and peroxide removal in the cryogenic U-tube differ significantly. Water loss as ice crystals in the exit air stream was observed throughout the runs. Additionally, the value of E/sub H2O/ increased with increasing humidity, and decreased with increased run time. A model of heat and mass transfer in the U-tube, based on Kays' transport correlations for developing laminar flow, yielded a reasonable agreement with experimental work. The model also predicts the observed phase change behavior of water in the U-tube, and supports the observed water loss mechanism.

  16. A passive integrative sampler for mercury vapor in air and neutral mercury species in water

    USGS Publications Warehouse

    Brumbaugh, W.G.; Petty, J.D.; May, T.W.; Huckins, J.N.

    2000-01-01

    A passive integrative mercury sampler (PIMS) based on a sealed polymeric membrane was effective for the collection and preconcentration of Hg0. Because the Hg is both oxidized and stabilized in the PIMS, sampling intervals of weeks to months are possible. The effective air sampling rate for a 15 x 2.5 cm device was about 21-equivalents/day (0.002 m3/day) and the detection limit for 4-week sampling was about 2 ng/m3 for conventional ICP-MS determination without clean-room preparation. Sampling precision was ??? 5% RSD for laboratory exposures, and 5-10% RSD for field exposures. These results suggest that the PIMS could be useful for screening assessments of Hg contamination and exposure in the environment, the laboratory, and the workplace. The PIMS approach may be particularly useful for applications requiring unattended sampling for extended periods at remote locations. Preliminary results indicate that sampling for dissolved gaseous mercury (DGM) and potentially other neutral mercury species from water is also feasible. Rigorous validation of the sampler performance is currently in progress. (C) 1999 Elsevier Science Ltd.A passive integrative mercury sampler (PIMS) based on a sealed polymeric membrane was effective for the collection and preconcentration of Hg0. Because the Hg is both oxidized and stabilized in the PIMS, sampling intervals of weeks to months are possible. The effective air sampling rate for a 15??2.5 cm device was about 21-equivalents/day (0.002 m3/day) and the detection limit for 4-week sampling was about 2 ng/m3 for conventional ICP-MS determination without clean-room preparation. Sampling precision was ???5% RSD for laboratory exposures, and 5-10% RSD for field exposures. These results suggest that the PIMS could be useful for screening assessments of Hg contamination and exposure in the environment, the laboratory, and the workplace. The PIMS approach may be particularly useful for applications requiring unattended sampling for extended

  17. A survey of an air monitoring program

    SciTech Connect

    Lee, M.B.

    1997-08-01

    The objective of this report is to compare personal air sampling data to stationary air sampling data and to bioassay data that was taken during the decontamination and decommissioning of sixty-one plutonium glove boxes at Argonne National Laboratory (ANL) in 1995. An air monitoring program administered at Argonne National Laboratory was assessed by comparing personal air sampler (PAS) data, stationary air sampler (SAS) data, and bioassay data. The study revealed that the PAS and SAS techniques were equivalent when averaged over all employees and all workdays, but the standard deviation was large. Also, large deviations were observed in individual samples. The correlation between individual PAS results and bioassay results was low. Personal air samplers and bioassay monitoring played complementary roles in assessing the workplace and estimating intakes. The PAS technique is adequate for detection and evaluation of contaminated atmospheres, whereas bioassay monitoring is better for determining individual intakes.

  18. Portable XRF analysis of occupational air filter samples from different workplaces using different samplers: final results, summary and conclusions.

    PubMed

    Harper, Martin; Pacolay, Bruce; Hintz, Patrick; Bartley, David L; Slaven, James E; Andrew, Michael E

    2007-11-01

    This paper concludes a five-year program on research into the use of a portable X-ray fluorescence (XRF) analyzer for analyzing lead in air sampling filters from different industrial environments, including mining, manufacturing and recycling. The results from four of these environments have already been reported. The results from two additional metal processes are presented here. At both of these sites, lead was a minor component of the total airborne metals and interferences from other elements were minimal. Nevertheless, only results from the three sites where lead was the most abundant metal were used in the overall calculation of method accuracy. The XRF analyzer was used to interrogate the filters, which were then subjected to acid digestion and analysis by inductively-coupled plasma optical-emission spectroscopy (ICP-OES). The filter samples were collected using different filter-holders or "samplers" where the size (diameter), depth and homogeneity of aerosol deposit varied from sampler to sampler. The aerosol collection efficiencies of the samplers were expected to differ, especially for larger particles. The distribution of particles once having entered the sampler was also expected to differ between samplers. Samplers were paired to allow the between-sampler variability to be addressed, and, in some cases, internal sampler wall deposits were evaluated and compared to the filter catch. It was found, rather surprisingly, that analysis of the filter deposits (by ICP-OES) of all the samplers gave equivalent results. It was also found that deposits on some of the sampler walls, which in some protocols are considered part of the sample, could be significant in comparison to the filter deposit. If it is concluded that wall-deposits should be analyzed, then XRF analysis of the filter can only give a minimum estimate of the concentration. Techniques for the statistical analysis of field data were also developed as part of this program and have been reported

  19. Testing flow-through air samplers for use in near-field vapour drift studies by measuring pyrimethanil in air after spraying.

    PubMed

    Geoghegan, Trudyanne S; Hageman, Kimberly J; Hewitt, Andrew J

    2014-03-01

    Pesticide volatilisation and subsequent vapour drift reduce a pesticide's efficiency and contribute to environmental contamination. High-volume air samplers (HVSs) are often used to measure pesticide concentrations in air but these samplers are expensive to purchase and require network electricity, limiting the number and type of sites where they can be deployed. The flow-through sampler (FTS) presents an opportunity to overcome these limitations. The FTS is a wind-driven passive sampler that has been developed to quantify organic contaminants in remote ecosystems. FTSs differ from other passive samplers in that they turn into the wind and use the wind to draw air through the sampling media. The main objective of this work was to evaluate the FTS in a near-field pesticide vapour drift study by comparing the concentrations of pyrimethanil in air measured using one HVS and three FTSs placed in the same location. Pyrimethanil was sprayed onto a vineyard as part of normal pest management procedures. Air samples were collected every eight hours for 48 h. The volume of air sampled by the FTSs was calculated using the measured relationship between ambient wind speed and the wind speed inside the sampler as determined with a separate wind tunnel study. The FTSs sampled 1.7 to 40.6 m(3) of air during each 8 h sampling period, depending on wind speed, whereas the mean volume sampled by the HVS was 128.7 m(3). Mean pyrimethanil concentrations ranged from 0.4 to 3.2 μg m(-3) of air. Inter-sampler reproducibility, as represented by percent relative standard deviation, for the three FTSs was ∼20%. The largest difference in FTS-derived versus HVS-derived pyrimethanil concentrations occurred during the lowest wind-speed period. During this period, it is likely that the FTS predominately acted like a traditional diffusion-based passive sampler. As indicated by both types of sampler, pyrimethanil concentrations in air changed by a factor of ∼2 during the two days after spaying

  20. Passive sampling for volatile organic compounds in indoor air-controlled laboratory comparison of four sampler types.

    PubMed

    McAlary, Todd; Groenevelt, Hester; Disher, Stephen; Arnold, Jason; Seethapathy, Suresh; Sacco, Paolo; Crump, Derrick; Schumacher, Brian; Hayes, Heidi; Johnson, Paul; Górecki, Tadeusz

    2015-05-01

    This article describes laboratory testing of four passive diffusive samplers for assessing indoor air concentrations of volatile organic compounds (VOCs), including SKC Ultra II, Radiello®, Waterloo Membrane Sampler (WMS) and Automated Thermal Desorption (ATD) tubes with two different sorbents (Tenax TA and Carbopack B). The testing included 10 VOCs (including chlorinated ethenes, ethanes, and methanes, aromatic and aliphatic hydrocarbons), spanning a range of properties and including some compounds expected to pose challenges (naphthalene, methyl ethyl ketone). Tests were conducted at different temperatures (17 to 30 °C), relative humidities (30 to 90% RH), face velocities (0.014 to 0.41 m s(-1)), concentrations (1 to 100 parts per billion by volume [ppbv]) and sampling durations (1 to 7 days). The results show that all of the passive samplers provided data that met the success criteria (relative percent difference [RPD] ≤ 45% of active sample concentrations and coefficient of variation [COV] ≤ 30%) in the majority of cases, but some compounds were problematic for some samplers. The passive sampler uptake rates depend to varying degrees on the sampler, sorbent, target compounds and environmental conditions, so field calibration is advantageous for the highest levels of data quality.

  1. Diffusion sampler testing at Naval Air Station North Island, San Diego County, California, November 1999 to January 2000

    USGS Publications Warehouse

    Vroblesky, Don A.; Peters, Brian C.

    2000-01-01

    Volatile organic compound concentrations in water from diffusion samplers were compared to concentrations in water obtained by low-flow purging at 15 observation wells at the Naval Air Station North Island, San Diego, California. Multiple diffusion samplers were installed in the wells. In general, comparisons using bladder pumps and diffusion samplers showed similar volatile organic carbon concentrations. In some wells, sharp concentration gradients were observed, such as an increase in cis-1,2-dichloroethene concentration from 100 to 2,600 micrograms per liter over a vertical distance of only 3.4 feet. In areas where such sharp gradients were observed, concentrations in water obtained by low-flow sampling at times reflected an average concentration over the area of influence; however, concentrations obtained by using the diffusion sampler seemed to represent the immediate vicinity of the sampler. When peristaltic pumps were used to collect ground-water samples by low-flow purging, the volatile organic compound concentrations commonly were lower than concentrations obtained by using diffusion samplers. This difference may be due to loss of volatiles by degassing under negative pressures in the sampling lines induced while using the peristaltic pump, mixing in the well screen, or possible short-circuiting of water from an adjacent depth. Diffusion samplers placed in buckets of freephase jet fuel (JP-5) and Stoddard solvent from observation wells did not show evidence of structural integrity loss during the 2 months of equilibration, and volatile organic compounds detected in the free-phase fuel also were detected in the water from the diffusion samplers.

  2. Polycyclic aromatic hydrocarbons in indoor air and environmental tobacco smoke measured with a new integrated organic vapor-particle sampler

    SciTech Connect

    Gundel, L.A.; Daisey, J.M.; Mahanama, K.R.R.; Lee, V.C. ); Stevens, R.K. . Atmospheric Research and Exposure Assessment Lab.)

    1993-01-01

    To avoid sampling artifacts, an integrated organic vapor-particle sampler (IOVPS) has been developed for polycyclic aromatic hydrocarbons (PAH). The ICIVPS is based on an XAD-4-coated annular denuder which strips gas phase species from the air stream before collection of particles on a filter. A second denuder downstream of the filter collects species desorbed ( blown off'') the particles during sampling. PAH are determined in extracts of both denuders and the filter. For indoor air with no combustion sources, the gas-phase concentrations of several semivolatile PAH measured with the IOVPS averaged about half of those found with a conventional filter-sorbent bed sampler. For envirorunental tobacco smoke the gas-phase concentrations of the same PAH from the IOVPS averaged 70% of those found with the sorbent bed sampler. Particulate-phase concentrations were correspondingly higher with the IOVPS, but measurable blow off' semivolatile PAH occurred.

  3. Photodegradation of polyaromatic hydrocarbons in passive air samplers: Field testing different deployment chambers

    USGS Publications Warehouse

    Bartkow, M.E.; Kennedy, K.E.; Huckins, J.N.; Holling, N.; Komarova, T.; Muller, J.F.

    2006-01-01

    Semi-permeable membrane devices (SPMDs) were loaded with deuterated anthracene and pyrene as performance reference compounds (PRCs) and deployed at a test site in four different chambers (open and closed box chamber, bowl chamber and cage chamber) for 29 days. The losses of PRCs and the uptake of polyaromatic hydrocarbons (PAHs) from the ambient air were quantified. UV-B levels measured in each deployment chamber indicated that SPMDs would be exposed to the most UV-B in the cage chamber and open box chamber. Significantly less PAHs were quantified in SPMDs deployed in the cage chamber and open box chamber compared to samplers from the other two chambers, suggesting that photodegradation of PAHs had occurred. The loss of PRCs confirmed these results but also showed that photodegradation was occurring in the closed box chamber. The bowl chamber appears to provide the best protection from the influence of direct photodegradation. ?? 2006 Elsevier Ltd. All rights reserved.

  4. Utilization of rice husk silica as adsorbent for BTEX passive air sampler under high humidity condition.

    PubMed

    Areerob, Thanita; Grisdanurak, Nurak; Chiarakorn, Siriluk

    2016-03-01

    Selective adsorbent of benzene, toluene, ethylbenzene, and xylenes (BTEX) was developed based on mesoporous silica materials, RH-MCM-41. It was synthesized from rice husk silica and modified by silane reagents. The silane reagents used in this study were trimethylchlorosilane (TMS), triisopropylchlorosilane (TIPS), and phenyldimethylchlorosilane (PDMS). Physiochemical properties of synthesized materials were characterized by small-angle X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), and surface area analysis. Materials packed in passive air sampler were tested for BTEX uptake capacity. The tests were carried out under an influence of relative humidity (25 to 99 %). Overall, RH-MCM-41 modified by TMS outperformed compared to those modified by other silane agents. The comparative BTEX adsorption on this material and commercial graphitized carbon black was reported. PMID:26573315

  5. Development of a new portable air sampler based on electrostatic precipitation.

    PubMed

    Roux, J M; Sarda-Estève, R; Delapierre, G; Nadal, M H; Bossuet, C; Olmedo, L

    2016-05-01

    Airborne particles are known to cause illness and to influence meteorological phenomena. It is therefore important to monitor their concentrations and to identify them. A challenge is to collect micro and nanoparticles, microorganisms as well as toxic molecules with a device as simple and small as possible to be used easily and everywhere. Electrostatic precipitation is an efficient method to collect all kinds of airborne particles. Furthermore, this method can be miniaturized. A portable, silent, and autonomous air sampler based on this technology is therefore being developed with the final objective to collect very efficiently airborne pathogens such as supermicron bacteria but also submicron viruses. Particles are collected on a dry surface so they may be concentrated afterwards in a small amount of liquid medium to be analyzed. It is shown that nearly 98 % of airborne particles from 10 nm to 3 μm are collected. PMID:26452658

  6. Determination of radionuclide concentrations in ground level air using the ASS-500 high volume sampler

    SciTech Connect

    Frenzel, E.; Arnold, D.; Wershofen, H.

    1996-06-01

    A method for determination of radionuclide concentrations in air aerosol samples collected by the high volume aerosol sampler ASS-500 was elaborated. The aerosol sampling station ASS-500 is a Stand alone, all-weather proofed instrument. It is designed for representative sampling of airborne radionuclides from ground level air at a height of about 1.5 m above ground level. The ASS-500 station enables continuous air monitoring both normal and emergency Situations. The collection of aerosols on the Petrianov FPP-15-1.5 type filter out of an air volume of about 100,000 m{sup 3} (sampling period 1 wk) or of about 250,000 m{sup 3} (sampling period 3 wk) admits accurate spectrometric low level measurements of natural and artificial radionuclides. The achieved detection limit is 0.5 {mu}Bq m{sup -3} and 0.2 {mu}Bq m{sup -3} for {sup 137}Cs, respectively. A new developed air flow Meter system allows to enhance the collected air volume to about 150,000 m{sup 3} per week and lowers the detection limit to <0.4 {mu}Bq m{sup -3} for {sup 137}Cs for weekly collected aerosol samples. In Poland the CLOR uses 9 Stations ASS-500 at different sites as atmospheric radioactivity control system. On the basis of spectrometric measurements of natural and artificial radionuclides in the collected aerosol samples at the different sites, CLOR establishes a weekly report about the radiological situation at Poland for responsible authorities. The very low achievable detection limit of the Station ASS-500 due 10 the high air flow fate and the long possible sampling period were the key argument for other government radiation protection authorities in Europe to introduce the Station ASS-500 into their low level radionuclide atmospheric monitoring programs (Austria, Belarus, France, Germany, Iceland, Spain, Switzerland, Ukraine).

  7. Design and laboratory testing of a new flow-through directional passive air sampler for ambient particulate matter.

    PubMed

    Lin, Chun; Solera Garcia, Maria Angeles; Timmis, Roger; Jones, Kevin C

    2011-03-01

    A new type of directional passive air sampler (DPAS) is described for collecting particulate matter (PM) in ambient air. The prototype sampler has a non-rotating circular sampling tray that is divided into covered angular channels, whose ends are open to winds from sectors covering the surrounding 360°. Wind-blown PM from different directions enters relevant wind-facing channels, and is retained there in collecting pools containing various sampling media. Information on source direction and type can be obtained by examining the distribution of PM between channels. Wind tunnel tests show that external wind velocities are at least halved over an extended area of the collecting pools, encouraging PM to settle from the air stream. Internal and external wind velocities are well-correlated over an external velocity range of 2.0-10.0 m s⁻¹, which suggests it may be possible to relate collected amounts of PM simply to ambient concentrations and wind velocities. Measurements of internal wind velocities in different channels show that velocities decrease from the upwind channel round to the downwind channel, so that the sampler effectively resolves wind directions. Computational fluid dynamics (CFD) analyses were performed on a computer-generated model of the sampler for a range of external wind velocities; the results of these analyses were consistent with those from the wind tunnel. Further wind tunnel tests were undertaken using different artificial particulates in order to assess the collection performance of the sampler in practice. These tests confirmed that the sampler can resolve the directions of sources, by collecting particulates preferentially in source-facing channels.

  8. Evaluation of two types of diffusive samplers and adsorbents for measuring 1,3-butadiene and benzene in air

    NASA Astrophysics Data System (ADS)

    Strandberg, Bo; Sunesson, Anna-Lena; Olsson, Katarina; Levin, Jan-Olof; Ljungqvist, Göran; Sundgren, Margit; Sällsten, Gerd; Barregard, Lars

    1,3-Butadiene and benzene are common air pollutants, the former being a suspected and the latter an established carcinogen. Road traffic and industry emissions are sources of these compounds. In order to assess the risk posed to the general population by ambient levels of these pollutants, diffusive samplers capable of monitoring them over both long timescales (weeks) and shorter periods (8-24 h) are needed. In this study, we evaluated a new diffusive sampler, the SKC-Ultra, and a partially validated sampler, the Radiello, both of which are compatible with thermal desorption. Two adsorbents, the graphitized carbon blacks Carbopack X and Carbograph 5, were also evaluated. Standard atmospheres of the target compounds were generated in order to determine uptake rates and to evaluate the effects of concentration, relative humidity, reverse-diffusion and storage of samplers. The samplers and adsorbents were also tested in a field study. Analysis and detection were performed using an automatic thermal desorber (ATD) connected to a gas chromatograph-flame ionization detector (GC/FID). Both samplers showed much higher uptake rates (ca. 25-50 fold) than those reported for the Perkin-Elmer sampler. The 24 h uptake rates for 1,3-butadiene and benzene obtained using the SKC-Ultra filled with Carbopack X were 14.9±0.8 (SD) and 16.0±1.4 (SD) mL min -1, respectively, and the corresponding figures for the Radiello were 22.0±0.9 (SD) and 30.4±1.1 (SD) mL min -1. Varying the atmospheric concentrations of the compounds had no effect on the uptake rate for the Carbopack X adsorbent and the samplers could be stored up to one month after sampling. Uptake rates of 1,3-butadiene declined over longer periods (one week). This was probably due to reverse diffusion, and the effect was less pronounced with the SKC-Ultra sampler. In summary, we consider the two samplers to be suitable both for stationary and personal monitoring of 1,3-butadiene and benzene, for the general population and

  9. An Improved, Automated Whole-Air Sampler and VOC Analysis System: Results from SONGNEX 2015

    NASA Astrophysics Data System (ADS)

    Lerner, B. M.; Gilman, J.; Tokarek, T. W.; Peischl, J.; Koss, A.; Yuan, B.; Warneke, C.; Isaacman-VanWertz, G. A.; Sueper, D.; De Gouw, J. A.; Aikin, K. C.

    2015-12-01

    Accurate measurement of volatile organic compounds (VOCs) in the troposphere is critical for the understanding of emissions and physical and chemical processes that can impact both air quality and climate. Airborne VOC measurements have proven challenging due to the requirements of short sample collection times (=10 s) to maximize spatial resolution and sampling frequency and high sensitivity (pptv) to chemically diverse hydrocarbons, halocarbons, oxygen- and nitrogen-containing VOCs. NOAA ESRL CSD has built an improved whole air sampler (iWAS) which collects compressed ambient air samples in electropolished stainless steel canisters, based on the NCAR HAIS Advanced Whole Air Sampler [Atlas and Blake]. Post-flight chemical analysis is performed with a custom-built gas chromatograph-mass spectrometer system that pre-concentrates analyte cryostatically via a Stirling cooler, an electromechanical chiller which precludes the need for liquid nitrogen to reach trapping temperatures. For the 2015 Shale Oil and Natural Gas Nexus Study (SONGNEX), CSD conducted iWAS measurements on 19 flights aboard the NOAA WP-3D aircraft between March 19th and April 27th. Nine oil and natural gas production regions were surveyed during SONGNEX and more than 1500 air samples were collected and analyzed. For the first time, we employed real-time mapping of sample collection combined with live data from fast time-response measurements (e.g. ethane) for more uniform surveying and improved target plume sampling. Automated sample handling allowed for more than 90% of iWAS canisters to be analyzed within 96 hours of collection - for the second half of the campaign improved efficiencies reduced the median sample age at analysis to 36 hours. A new chromatography peak-fitting software package was developed to minimize data reduction time by an order of magnitude without a loss of precision or accuracy. Here we report mixing ratios for aliphatic and aromatic hydrocarbons (C2-C8) along with select

  10. Assessment of the spatial distribution of coplanar PCBs, PCNs, and PBDEs in a multi-industry region of South Korea using passive air samplers.

    PubMed

    Baek, Song-Yee; Choi, Sung-Deuk; Lee, Se-Jin; Chang, Yoon-Seok

    2008-10-01

    Coplanar polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polybrominated diphenyl ethers (PBDEs) were sampled using polyurethane foam (PUF) disk passive air samplers (PAS) at 19 sites in a heavily industrialized region of South Korea for 6 months (January-July 2006). The levels and spatial distribution of these three chemical groups were investigated to identify potential sources and transport in the study area, which can be divided into five regions: a steel-manufacturing complex, a residential area near the steel complex, a rural area, a semi-industrial area, and a petrochemical-manufacturing complex. Air concentrations (pg x m(-3)) were estimated using an average sampling rate of 3.0 m3 x day(-1) and ranged as follows: coplanar PCBs (0.8-16), PCNs (1.7-35), and PBDEs (3.8-24). The levels of coplanar PCBs and PBDEs were found to be the highest in the steel complex, followed by the petrochemical complex and the semi-industrial area. In addition, a high level of PCNs was measured near a petrochemical-processing plant. However, the residential area near the steel complex and the rural area showed relatively low concentrations of these chemicals, suggesting that the steel and petrochemical industries are probably important sources in the study area, but these potential sources do not strongly influence the surrounding areas.

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

    PubMed Central

    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

  12. The effects of rice canopy on the air-soil exchange of polycyclic aromatic hydrocarbons and organochlorine pesticides using paired passive air samplers.

    PubMed

    Wang, Yan; Wang, Shaorui; Luo, Chunling; Li, Jun; Ming, Lili; Zhang, Gan; Li, Xiangdong

    2015-05-01

    The rice canopy in paddy fields can influence the air-soil exchange of organic chemicals. We used paired passive air samplers to assess the exchange of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in a paddy field, South China. Levels of OCPs and light PAHs were generally higher under the canopy than above it. We found that the rice canopy can physically obstruct the evaporation of most OCPs and light PAHs, and can also act as a barrier to the gaseous deposition of p,p'-DDT and heavy PAHs. Paddy fields can behave as a secondary source of OCPs and light PAHs. The homolog patterns of these two types of chemical varied slightly between the air below and above the rice canopy, implying contributions of different sources. Paired passive air samplers can be used effectively to assess the in situ air-soil exchange of PAHs and OCPs in subtropical paddy fields.

  13. Screening of atmospheric short- and medium-chain chlorinated paraffins in India and Pakistan using polyurethane foam based passive air sampler.

    PubMed

    Chaemfa, Chakra; Xu, Yue; Li, Jun; Chakraborty, Paromita; Hussain Syed, Jabir; Naseem Malik, Riffat; Wang, Yan; Tian, Chongguo; Zhang, Gan; Jones, Kevin C

    2014-05-01

    Production and use of chlorinated paraffins (CPs) have been increasing in India. Distribution of CPs in the area and vicinity have become a great concern due to their persistency and toxicity. Polyurethane foam based passive air samplers (PUF-PAS) was deployed in order to screen the presence of short- and medium- chain chlorinated paraffins (SCCPs and MCCPs) in the outdoor atmosphere at many sites in India (in winter 2006) and Pakistan (in winter 2011). Concentrations of SCCPs and MCCPs ranged from not detected (ND) to 47.4 and 0 to 38.2 ng m(-3) with means of 8.11 and 4.83 ng m(-3), respectively. Indian concentrations showed higher average levels of both SCCPs and MCCPs India (10.2 ng m(-3) and 3.62 ng m(-3)than the samples from Pakistan (5.13 ng m(-3) and 4.21 ng m(-3)). Relative abundance patterns of carbon number are C10 > C11 > C12 ∼ C13 for SCCPs and C14 > C15 > C16 C17 for MCCP with similarity to the profiles of samples from China, the biggest CPs producer in the world. Principal Component Analysis suggested that detected SCCPs and MCCPs in this study originated from the same emission source.

  14. Assessment of the air-soil partitioning of polycyclic aromatic hydrocarbons in a paddy field using a modified fugacity sampler.

    PubMed

    Wang, Yan; Luo, Chunling; Wang, Shaorui; Liu, Junwen; Pan, Suhong; Li, Jun; Ming, Lili; Zhang, Gan; Li, Xiangdong

    2015-01-01

    Rice, one of the most widely cultivated crops, has received great attention in contaminant uptake from soil and air, especially for the special approaches used for its cultivation. The dry-wet alternation method can influence the air-soil partitioning of semivolatile organic compounds (SVOCs) in the paddy ecosystem. Here, we modified a fugacity sampler to investigate the air-surface in situ partitioning of ubiquitous polycyclic aromatic hydrocarbons (PAHs) at different growth stages in a suburban paddy field in South China. The canopy of rice can form a closed space, which acts like a chamber that can force the air under the canopy to equilibrate with the field surface. When we compared the fugacities calculated using a fugacity model of the partition coefficients to the measured fugacities, we observed similar trends in the variation, but significantly different values between different growing stages, especially during the flooding stages. However, the measured and calculated fugacity fractions were comparable when uncertainties in our calculations were considered, with the exception of the high molecular weight (HMW) PAHs. The measured fugacity fractions suggested that the HMW PAHs were also closed to equilibrium between the paddy field and atmosphere. The modified fugacity sampler provided a novel way of accurately determining the in situ air-soil partitioning of SVOCs in a wet paddy field.

  15. Field-based evaluation of semipermeable membrane devices (SPMDs) as passive air samplers of polyaromatic hydrocarbons (PAHs)

    USGS Publications Warehouse

    Bartkow, M.E.; Huckins, J.N.; Muller, J.F.

    2004-01-01

    Semipermeable membrane devices (SPMDs) have been used as passive air samplers of semivolatile organic compounds in a range of studies. However, due to a lack of calibration data for polyaromatic hydrocarbons (PAHs), SPMD data have not been used to estimate air concentrations of target PAHs. In this study, SPMDs were deployed for 32 days at two sites in a major metropolitan area in Australia. High-volume active sampling systems (HiVol) were co-deployed at both sites. Using the HiVol air concentration data from one site, SPMD sampling rates were measured for 12 US EPA Priority Pollutant PAHs and then these values were used to determine air concentrations at the second site from SPMD concentrations. Air concentrations were also measured at the second site with co-deployed HiVols to validate the SPMD results. PAHs mostly associated with the vapour phase (Fluorene to Pyrene) dominated both the HiVol and passive air samples. Reproducibility between replicate passive samplers was satisfactory (CV<20%) for the majority of compounds. Sampling rates ranged between 0.6 and 6.1 m3 d-1. SPMD-based air concentrations were calculated at the second site for each compound using these sampling rates and the differences between SPMD-derived air concentrations and those measured using a HiVol were, on average, within a factor of 1.5. The dominant processes for the uptake of PAHs by SPMDs were also assessed. Using the SPMD method described herein, estimates of particulate sorbed airborne PAHs with five rings or greater were within 1.8-fold of HiVol measured values. ?? 2004 Elsevier Ltd. All rights reserved.

  16. Field calibration of rapidly equilibrating thin-film passive air samplers and their potential application for low-volume air sampling studies.

    PubMed

    Farrar, N J; Harner, T J; Sweetman, A J; Jones, K C

    2005-01-01

    This paper reports on a field calibration and ambient deployment study with rapidly equilibrating thin-film passive air samplers. POlymer-coated Glass (POG) samplers have a coating of ethylene vinyl acetate (EVA) less than 1 microm thick coated on to glass, which can be dissolved off after exposure and prepared for quantification of persistent organic pollutants (POPs) that have partitioned into the film during field exposure. In this study, POGs were exposed for up to 18 d, in a study to assess compound uptake rates and their time to approach equilibrium. Results confirmed theoretical predictions, with time to equilibrium varying between a few hours to ca. 20 d for PCB-18 and PCB-138, respectively. Performance reference compounds and contaminated POGs were used to investigate depuration kinetics, confirming that lighter congeners behave extremely dynamically with substantial losses from the films over periods of a few hours. Repeated deployments of the samplers for different3-d periods yielded detectable levels of a range of PCB congeners, which had partitioned from as little as approximately 2 to 10 m3 air. This highlights the potential utility of POGs for extremely sensitive and dynamic passive air sampling in the future to help improve understanding of sources, environmental fate, and behavior of POPs. Recommendations are made for future improvements/refinements in POG sampling and handling procedures.

  17. A wind tunnel test of newly developed personal bioaerosol samplers.

    PubMed

    Su, Wei-Chung; Tolchinsky, Alexander D; Sigaev, Vladimir I; Cheng, Yung Sung

    2012-07-01

    In this study the performance of two newly developed personal bioaerosol samplers was evaluated. The two test samplers are cyclone-based personal samplers that incorporate a recirculating liquid film. The performance evaluations focused on the physical efficiencies that a personal bioaerosol sampler could provide, including aspiration, collection, and capture efficiencies. The evaluation tests were carried out in a wind tunnel, and the test personal samplers were mounted on the chest of a full-size manikin placed in the test chamber of the wind tunnel. Monodisperse fluorescent aerosols ranging from 0.5 to 20 microm were used to challenge the samplers. Two wind speeds of 0.5 and 2.0 m/sec were employed as the test wind speeds in this study. The test results indicated that the aspiration efficiency of the two test samplers closely agreed with the ACGIH inhalable convention within the size range of the test aerosols. The aspiration efficiency was found to be independent of the sampling orientation. The collection efficiency acquired from these two samplers showed that the 50% cutoff diameters were both around 0.6 microm. However the wall loss of these two test samplers increased as the aerosol size increased, and the wall loss of PAS-4 was considerably higher than that of PAS-5, especially in the aerosol size larger than 5 microm, which resulted in PAS-4 having a relatively lower capture efficiency than PAS-5. Overall, the PAS-5 is considered a better personal bioaerosol sampler than the PAS-4.

  18. Comparison of passive diffusion bag samplers and submersible pump sampling methods for monitoring volatile organic compounds in ground water at Area 6, Naval Air Station, Whidbey Island, Washington

    USGS Publications Warehouse

    Huffman, Raegan L.

    2002-01-01

    Ground-water samples were collected in April 1999 at Naval Air Station Whidbey Island, Washington, with passive diffusion samplers and a submersible pump to compare concentrations of volatile organic compounds (VOCs) in water samples collected using the two sampling methods. Single diffusion samplers were installed in wells with 10-foot screened intervals, and multiple diffusion samplers were installed in wells with 20- to 40-foot screened intervals. The diffusion samplers were recovered after 20 days and the wells were then sampled using a submersible pump. VOC concentrations in the 10-foot screened wells in water samples collected with diffusion samplers closely matched concentrations in samples collected with the submersible pump. Analysis of VOC concentrations in samples collected from the 20- to 40-foot screened wells with multiple diffusion samplers indicated vertical concentration variation within the screened interval, whereas the analysis of VOC concentrations in samples collected with the submersible pump indicated mixing during pumping. The results obtained using the two sampling methods indicate that the samples collected with the diffusion samplers were comparable with and can be considerably less expensive than samples collected using a submersible pump.

  19. Stability of polycyclic aromatic compounds in polyurethane foam-type passive air samplers upon O3 exposure

    NASA Astrophysics Data System (ADS)

    Jariyasopit, Narumol; Liu, Yongchun; Liggio, John; Harner, Tom

    2015-11-01

    Stability of polycyclic aromatic compounds (PACs) in polyurethane foam (PUF) disks upon O3 exposure was studied in a flow tube. A wide range of PACs was evaluated by spiking PUF disks with PACs and exposing to O3 at concentrations that were equivalent to two months exposure, a typical deployment period for these passive air samplers. Ambient concentrations of O3 (∼50 ppb) at 0% and 50% relative humidity (RH) were applied. At 0% RH, 23 of 68 PACs yielded more than 50% loss after exposure. The mean percent loss was 30% with perylene and 9,10-dimethylanthracene the most reactive polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs, respectively. At 50% RH, 77% of the studied PACs was stable upon O3 exposure (PACexposed/PACunexposed > 0.7). The mean percent loss was 17% and only 7 of 68 PACs yielded greater than 50% loss. In general, the reactivity of most of the PACs decreased at higher RH, except for the reactive PAHs (acenaphthylene, 2,3-dimethylanthracene, 9,10-dimethylanthracene, dibenzothiophene, and 2-methyldibenzothiophene) which demonstrated lower RH dependence. The experimental conditions in this study represent a worst case scenario for the stability of PACs sorbed to PUF. In reality, the sampling of PACs in ambient air represents an 'aged' component of PACs where the most reactive species have already partially been removed. Also, PACs in ambient air will be associated with the particle phase to varying extents that will help to enhance their stability. Therefore, under regular operating conditions, over a 2-month exposure, we expect a minimal error in the measurement of total concentration of PACs in air using the PUF disk passive sampler.

  20. Polycyclic aromatic hydrocarbons in indoor air and environmental tobacco smoke measured with a new integrated organic vapor-particle sampler. Revision

    SciTech Connect

    Gundel, L.A.; Daisey, J.M.; Mahanama, K.R.R.; Lee, V.C.; Stevens, R.K.

    1993-01-01

    To avoid sampling artifacts, an integrated organic vapor-particle sampler (IOVPS) has been developed for polycyclic aromatic hydrocarbons (PAH). The ICIVPS is based on an XAD-4-coated annular denuder which strips gas phase species from the air stream before collection of particles on a filter. A second denuder downstream of the filter collects species desorbed (``blown off``) the particles during sampling. PAH are determined in extracts of both denuders and the filter. For indoor air with no combustion sources, the gas-phase concentrations of several semivolatile PAH measured with the IOVPS averaged about half of those found with a conventional filter-sorbent bed sampler. For envirorunental tobacco smoke the gas-phase concentrations of the same PAH from the IOVPS averaged 70% of those found with the sorbent bed sampler. Particulate-phase concentrations were correspondingly higher with the IOVPS, but measurable ``blow off` semivolatile PAH occurred.

  1. Passive air sampler as a tool for long-term air pollution monitoring: Part 1. Performance assessment for seasonal and spatial variations.

    PubMed

    Klánová, Jana; Kohoutek, Jirí; Hamplová, Lenka; Urbanová, Petra; Holoubek, Ivan

    2006-11-01

    The potential of passive air sampling devices (polyurethane foam disks) to assess the influence of local sources on the quality of the surrounding environment was investigated. DEZA Valasske Mezirici, a coal tar and mixed tar oils processing plant, and Spolana Neratovice, a chemical factory with the history of high production of organochlorinated pesticides (OCPs), were selected as the point sources of PAHs, and OCPs, respectively. Levels of PCBs, OCPs and PAHs were determined for all sampling sites and sampling periods. The study brought useful data about the air concentrations of POPs in the investigated regions. More important, it provided information on the transport and fate of POPs in the vicinity of local sources of contamination useful for the estimation of their influence. Very good capability of passive samplers to reflect temporal and spatial fluctuation in concentrations of persistent organic pollutants in the ambient air was confirmed which makes them applicable for monitoring on the local scale.

  2. FIELD METHOD COMPARISON BETWEEN PASSIVE AIR SAMPLERS AND CONTINUOUS MONITORS FOR VOLATILE ORGANIC COMPOUNDS AND NO2 IN EL PASO, TEXAS, USA

    EPA Science Inventory

    Passive sampling of gas-phase air toxics and criteria pollutants has become an attractive monitoring method in human exposure studies due to the relatively low sampling cost and ease of use. This study evaluates the performance of Model 3300 Ogawa(TM) Passive NO2 Samplers and 3...

  3. Assessment of diffusion parameters of new passive samplers using optical chemical sensor for on-site measuring formaldehyde in indoor air: experimental and numerical studies.

    PubMed

    Vignau-Laulhere, Jane; Mocho, Pierre; Plaisance, Hervé; Raulin, Katarzyna; Desauziers, Valérie

    2016-03-01

    New passive samplers using a sensor consisting of a sol-gel matrix entrapping Fluoral-P as sampling media were developed for the determination of formaldehyde in indoor air. The reaction between Fluoral-P and formaldehyde produces a colored compound which is quantified on-site by means of a simple optical reading module. The advantages of this sensor are selectivity, low cost, ppb level limit of detection, and on-site direct measurement. In the development process, it is necessary to determine the sampling rate, a key parameter that cannot be directly assessed in the case of diffusive samplers using optical chemical sensor. In this study, a methodology combining experimental tests and numerical modeling is proposed and applied at five different radial diffusive samplers equipped with the same optical chemical sensor to assess the sampled material flows and sampling rates. These radial diffusive samplers differ in the internal volume of the sampler (18.97 and 6.14 cm(3)), the position of sensor inside the sampler (in front and offset of 1.2 cm above the membrane) and the width of the diffusion slot (1.4 and 5.9 mm). The influences of these three parameters (internal volume, position of sensor inside the sampler, and width of the diffusion slot) were assessed and discussed with regard to the formaldehyde sampling rate and water uptake by sensor (potential interference of measure). Numerical simulations based on Fick's laws are in agreement with the experimental results and provide to estimate the effective diffusion coefficient of formaldehyde through the membrane (3.50 × 10(-6) m(2) s(-1)). Conversion factors between the sensor response, sampled formaldehyde mass and sampling rate were also assessed.

  4. Assessment of diffusion parameters of new passive samplers using optical chemical sensor for on-site measuring formaldehyde in indoor air: experimental and numerical studies.

    PubMed

    Vignau-Laulhere, Jane; Mocho, Pierre; Plaisance, Hervé; Raulin, Katarzyna; Desauziers, Valérie

    2016-03-01

    New passive samplers using a sensor consisting of a sol-gel matrix entrapping Fluoral-P as sampling media were developed for the determination of formaldehyde in indoor air. The reaction between Fluoral-P and formaldehyde produces a colored compound which is quantified on-site by means of a simple optical reading module. The advantages of this sensor are selectivity, low cost, ppb level limit of detection, and on-site direct measurement. In the development process, it is necessary to determine the sampling rate, a key parameter that cannot be directly assessed in the case of diffusive samplers using optical chemical sensor. In this study, a methodology combining experimental tests and numerical modeling is proposed and applied at five different radial diffusive samplers equipped with the same optical chemical sensor to assess the sampled material flows and sampling rates. These radial diffusive samplers differ in the internal volume of the sampler (18.97 and 6.14 cm(3)), the position of sensor inside the sampler (in front and offset of 1.2 cm above the membrane) and the width of the diffusion slot (1.4 and 5.9 mm). The influences of these three parameters (internal volume, position of sensor inside the sampler, and width of the diffusion slot) were assessed and discussed with regard to the formaldehyde sampling rate and water uptake by sensor (potential interference of measure). Numerical simulations based on Fick's laws are in agreement with the experimental results and provide to estimate the effective diffusion coefficient of formaldehyde through the membrane (3.50 × 10(-6) m(2) s(-1)). Conversion factors between the sensor response, sampled formaldehyde mass and sampling rate were also assessed. PMID:26847188

  5. Continued growth for military PAs.

    PubMed

    Salyer, Steven W

    2002-10-01

    The US military physician assistant (PA) originated from the corpsmen and medics of the army, navy, air force, and Coast Guard. PAs have been present in every military campaign since 1980 and serve in a wide variety of medical roles. Their combat role has expanded so that in many instances the PA has replaced the physician as the front-line care provider. All have moved from warrant officer into the commissioned officer ranks, a change that has enabled them to rise into command and administrative positions. Narrowing of the pay differential between military and civilian PAs has contributed to their retention.

  6. Sampler bias -- Phase 1

    SciTech Connect

    Blanchard, R.J.

    1995-03-07

    This documents Phase 1 determinations on sampler induced bias for four sampler types used in tank characterization. Each sampler, grab sampler or bottle-on-a-string, auger sampler, sludge sampler and universal sampler, is briefly discussed and their physical limits noted. Phase 2 of this document will define additional testing and analysis to further define Sampler Bias.

  7. Analytical sensitivity of air samplers based on uniform point-source exposure to airborne Porcine reproductive and respiratory syndrome virus and swine influenza virus

    PubMed Central

    Hermann, Joseph R.; Zimmerman, Jeffrey J.

    2008-01-01

    Research and surveillance activities involving airborne pathogens rely on the capture and enumeration of pathogens suspended in aerosols. The objective of this study was to estimate the analytical sensitivity (detection threshold) of each of 4 air samplers for Porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV). In a 5-min sampling period under controlled conditions, the analytical sensitivity of the AGI-30 (Ace Glass, Vineland, New Jersey, USA), AGI-4 (Ace Glass), SKC BioSampler (SKC, Eighty Four, Pennsylvania, USA), and Midwest Micro-Tek sampler (Midwest Micro-Tek, Brookings, South Dakota, USA) was calculated at 1 × 101.1, 1 × 101.3, 1 × 101.1, and 1 × 101.2 median tissue culture infectious dose (TCID50) equivalents for PRRSV and 1 × 101.4, 1 × 101.1, 1 × 101.6, and 1 × 101.2 TCID50 equivalents for SIV [per 60 L (5-min sampling period)]. Despite marked differences in sampler design, no statistically significant difference in analytical sensitivity was detected between the samplers for collection of artificially produced aerosols containing cell-culture-propagated PRRSV or SIV. PMID:19086377

  8. Concentrations, Trends, and Air-Water Exchange of PAHs and PBDEs Derived from Passive Samplers in Lake Superior in 2011.

    PubMed

    Ruge, Zoe; Muir, Derek; Helm, Paul; Lohmann, Rainer

    2015-12-01

    Polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenylethers (PBDEs) are both currently released into the environment from anthropogenic activity. Both are hence primarily associated with populated or industrial areas, although wildfires can be an important source of PAHs, as well. Polyethylene passive samplers (PEs) were simultaneously deployed in surface water and near surface atmosphere to determine spatial trends and air-water gaseous exchange of 21 PAHs and 11 PBDEs at 19 sites across Lake Superior in 2011. Surface water and atmospheric PAH concentrations were greatest at urban sites (up to 65 ng L(-1) and 140 ng m(-3), respectively, averaged from June to October). Near populated regions, PAHs displayed net air-to-water deposition, but were near equilibrium off-shore. Retene, probably depositing following major wildfires in the region, dominated dissolved PAH concentrations at most Lake Superior sites. Atmospheric and dissolved PBDEs were greatest near urban and populated sites (up to 6.8 pg L(-1) and 15 pg m(-3), respectively, averaged from June to October), dominated by BDE-47. At most coastal sites, there was net gaseous deposition of BDE-47, with less brominated congeners contributing to Sault Ste. Marie and eastern open lake fluxes. Conversely, the central open lake and Eagle Harbor sites generally displayed volatilization of PBDEs into the atmosphere, mainly BDE-47. PMID:26436513

  9. Using Portable Samplers to Determine the Effect of Roadside Vegetation on Near-Road Air Quality

    EPA Science Inventory

    Growing evidence exists that populations spending significant amounts of time near major roads face increased risks for several adverse health effects.1 These effects may be attributable to increased exposure to particulate matter (PM), gaseous criteria pollutants, and air toxic...

  10. Improved particle impactor assembly for size selective high volume air sampler

    DOEpatents

    Langer, G.

    1987-03-23

    Air containing entrained particulate matter is directed through a plurality of parallel, narrow, vertically oriented apertures of an inlet element toward an adjacently located, relatively large, dust impaction surface preferably covered with an adhesive material. The air flow turns over the impaction surface, leaving behind, the relatively larger particles and passes through two elongate apertures defining the outer bounds of the impaction collection surface to pass through divergent passages which slow down and distribute the air flow, with entrained smaller particles, over a fine filter element that separates the fine particles from the air. By appropriate selection of dimensions and the number of inlet apertures air flow through the inlet element is provided a nonuniform velocity distribution with the lower velocities being obtained near the center of the inlet apertures, to separate out particles larger than a certain predetermined size on the impaction collection surface. The impaction collection surface, even in a moderately sized apparatus, is thus relatively large and permits the prolonged sampling of air for periods extending to four weeks. 6 figs.

  11. Field evaluation and calibration of a small axial passive air sampler for gaseous and particle bound polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs.

    PubMed

    Magnusson, Roger; Arnoldsson, Kristina; Lejon, Christian; Hägglund, Lars; Wingfors, Håkan

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated analogues (OPAHs) are ubiquitous air pollutants known to cause adverse health effects. PAH air levels are commonly monitored by active sampling but passive sampling has become popular because of its lower cost and simplicity, which facilitate long-term sampling and increased spatial coverage. However, passive samplers are less suitable for short-term sampling and are in general less accurate than active samplers because they require reliable sampling rate (Rs) measurements for individual analytes under diverse environmental conditions. In this study a small passive sampler designed to sample both particle-bound and gaseous compounds was evaluated and calibrated for PAHs and OPAHs in a traffic environment by co-deployment with active samplers for two weeks. Despite the relatively low average air concentrations of PM10 (20 μg/m(3)), PM2.5 (5 μg/m(3)), total PAHs (4.2 ng/m(3)), and OPAHs (2.3 ng/m(3)) at the site, detectable quantities (on average 24 times above blank values) of the full range of PAHs and OPAHs were captured, with low variability (average RSD of 16%). This was accomplished by using a Tenax(®) TA-modified glass fiber substrate that is compatible with highly sensitive thermal desorption GC-MS analysis, which made it possible to achieve detection limits per sample in the pg range. Experiments with inverted samplers revealed that the relative contribution of gravitational settling to the sampling of particles carrying PAHs and OPAHs was around 3.5 times larger than other deposition mechanisms. Average Rs values for individual OPAHs and PAHs were 0.046 ± 0.03 m(3)/day and 0.12 ± 0.07 m(3)/day, respectively, with no appreciable difference between the values for particle-associated and gaseous compounds. Furthermore, the Rs values were competitive with other currently used passive samplers if normalized for substrate area. Overall, the new sampler's performance, simplicity and

  12. Air Pollutant Emissions from Oil and Gas Production pads (Investigating Low Cost Passive Samplers)

    EPA Science Inventory

    To help achieve the goal of sustainable, environmentally responsible development of oil and gas resources, it isnecessary to understand the potential for air pollutant emissions from various extraction and production (E&P)processes at the upstream, wellpad level. Upstream oil and...

  13. Assessing polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in air across Latin American countries using polyurethane foam disk passive air samplers.

    PubMed

    Schuster, Jasmin K; Harner, Tom; Fillmann, Gilberto; Ahrens, Lutz; Altamirano, Jorgelina C; Aristizábal, Beatriz; Bastos, Wanderley; Castillo, Luisa Eugenia; Cortés, Johana; Fentanes, Oscar; Gusev, Alexey; Hernandez, Maricruz; Ibarra, Martín Villa; Lana, Nerina B; Lee, Sum Chi; Martínez, Ana Patricia; Miglioranza, Karina S B; Puerta, Andrea Padilla; Segovia, Federico; Siu, May; Tominaga, Maria Yumiko

    2015-03-17

    A passive air sampling network has been established to investigate polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) at Global Atmospheric Passive Sampling (GAPS) sites and six additional sites in the Group of Latin American and Caribbean Countries (GRULAC) region. The air sampling network covers background, agricultural, rural, and urban sites. Samples have been collected over four consecutive periods of 6 months, which started in January 2011 [period 1 (January to June 2011), period 2 (July to December 2011), period 3 (January to June 2012), and period 4 (July 2012 to January 2013)]. Results show that (i) the GAPS passive samplers (PUF disk type) and analytical methodology are adequate for measuring PCDD/F burdens in air and (ii) PCDD/F concentrations in air across the GRULAC region are widely variable by almost 2 orders of magnitude. The highest concentrations in air of Σ4-8PCDD/Fs were found at the urban site São Luis (Brazil, UR) (i.e., 2560 fg/m3) followed by the sites in São Paulo (Brazil, UR), Mendoza (Argentina, RU), and Sonora (Mexico, AG) with values of 1690, 1660, and 1610 fg/m3, respectively. Very low concentrations of PCDD/Fs in air were observed at the background site Tapanti (Costa Rica, BA), 10.8 fg/m3. This variability is attributed to differences in site characteristics and potential local/regional sources as well as meteorological influences. The measurements of PCDD/Fs in air agree well with model-predicted concentrations performed using the Global EMEP Multimedia Modeling System (GLEMOS) and emission scenario constructed on the basis of the UNEP Stockholm Convention inventory of dioxin and furan emissions. PMID:25686404

  14. Assessing polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in air across Latin American countries using polyurethane foam disk passive air samplers.

    PubMed

    Schuster, Jasmin K; Harner, Tom; Fillmann, Gilberto; Ahrens, Lutz; Altamirano, Jorgelina C; Aristizábal, Beatriz; Bastos, Wanderley; Castillo, Luisa Eugenia; Cortés, Johana; Fentanes, Oscar; Gusev, Alexey; Hernandez, Maricruz; Ibarra, Martín Villa; Lana, Nerina B; Lee, Sum Chi; Martínez, Ana Patricia; Miglioranza, Karina S B; Puerta, Andrea Padilla; Segovia, Federico; Siu, May; Tominaga, Maria Yumiko

    2015-03-17

    A passive air sampling network has been established to investigate polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) at Global Atmospheric Passive Sampling (GAPS) sites and six additional sites in the Group of Latin American and Caribbean Countries (GRULAC) region. The air sampling network covers background, agricultural, rural, and urban sites. Samples have been collected over four consecutive periods of 6 months, which started in January 2011 [period 1 (January to June 2011), period 2 (July to December 2011), period 3 (January to June 2012), and period 4 (July 2012 to January 2013)]. Results show that (i) the GAPS passive samplers (PUF disk type) and analytical methodology are adequate for measuring PCDD/F burdens in air and (ii) PCDD/F concentrations in air across the GRULAC region are widely variable by almost 2 orders of magnitude. The highest concentrations in air of Σ4-8PCDD/Fs were found at the urban site São Luis (Brazil, UR) (i.e., 2560 fg/m3) followed by the sites in São Paulo (Brazil, UR), Mendoza (Argentina, RU), and Sonora (Mexico, AG) with values of 1690, 1660, and 1610 fg/m3, respectively. Very low concentrations of PCDD/Fs in air were observed at the background site Tapanti (Costa Rica, BA), 10.8 fg/m3. This variability is attributed to differences in site characteristics and potential local/regional sources as well as meteorological influences. The measurements of PCDD/Fs in air agree well with model-predicted concentrations performed using the Global EMEP Multimedia Modeling System (GLEMOS) and emission scenario constructed on the basis of the UNEP Stockholm Convention inventory of dioxin and furan emissions.

  15. A modified siphon sampler for shallow water

    USGS Publications Warehouse

    Diehl, Timothy H.

    2008-01-01

    A modified siphon sampler (or 'single-stage sampler') was developed to sample shallow water at closely spaced vertical intervals. The modified design uses horizontal rather than vertical sample bottles. Previous siphon samplers are limited to water about 20 centimeters (cm) or more in depth; the modified design can sample water 10 cm deep. Several mounting options were used to deploy the modified siphon sampler in shallow bedrock streams of Middle Tennessee, while minimizing alteration of the stream bed. Sampling characteristics and limitations of the modified design are similar to those of the original design. Testing showed that the modified sampler collects unbiased samples of suspended silt and clay. Similarity of the intake to the original siphon sampler suggests that the modified sampler would probably take downward-biased samples of suspended sand. Like other siphon samplers, it does not sample isokinetically, and the efficiency of sand sampling can be expected to change with flow velocity. The sampler needs to be located in the main flow of the stream, and is subject to damage from rapid flow and floating debris. Water traps were added to the air vents to detect the flow of water through the sampler, which can cause a strong upward bias in sampled suspended-sediment concentration. Water did flow through the sampler, in some cases even when the top of the air vent remained above water. Air vents need to be extended well above maximum water level to prevent flow through the sampler.

  16. A preliminary investigation into the use of Red Pine (Pinus Resinosa) tree cores as historic passive samplers of POPs in outdoor air

    NASA Astrophysics Data System (ADS)

    Rauert, Cassandra; Harner, Tom

    2016-09-01

    The suitability of Red Pine trees (Pinus Resinosa) to act as passive samplers for persistent organic pollutants (POPs) in outdoor air and to provide historic information on air concentration trends was demonstrated in this preliminary investigation. Red Pine tree cores from Toronto, Canada, were tested for polycyclic aromatic hydrocarbon (PAHs), alkylated-PAHs, nitro and oxy-PAHs, polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (novel BFRs). The PBDEs and novel BFRs demonstrated a similar relative contribution in cores representing 30 years of tree growth, to that reported in contemporary air samples. Analysis of tree ring segments of 5-15 years resulted in detectable concentrations of some PAHs and alk-PAHs and demonstrated a transition from petrogenic sources to pyrogenic sources over the period 1960-2015. A simple uptake model was developed that treats the tree rings as linear-phase passive air samplers. The bark infiltration factor, IFBARK, is a key parameter of the model that reflects the permeability of the bark to allow chemicals to be transferred from ambient air to the outer tree layer (cambium). An IFBARK of about 2% was derived for the Red Pine trees based on tree core and air monitoring data.

  17. Correlations between short-term mobile monitoring and long-term passive sampler measurements of traffic-related air pollution

    NASA Astrophysics Data System (ADS)

    Riley, Erin A.; Schaal, LaNae; Sasakura, Miyoko; Crampton, Robert; Gould, Timothy R.; Hartin, Kris; Sheppard, Lianne; Larson, Timothy; Simpson, Christopher D.; Yost, Michael G.

    2016-05-01

    Mobile monitoring has provided a means for broad spatial measurements of air pollutants that are otherwise impractical to measure with multiple fixed site sampling strategies. However, the larger the mobile monitoring route the less temporally dense measurements become, which may limit the usefulness of short-term mobile monitoring for applications that require long-term averages. To investigate the stationarity of short-term mobile monitoring measurements, we calculated long term medians derived from a mobile monitoring campaign that also employed 2-week integrated passive sampler detectors (PSD) for NOx, Ozone, and nine volatile organic compounds at 43 intersections distributed across the entire city of Baltimore, MD. This is one of the largest mobile monitoring campaigns in terms of spatial extent undertaken at this time. The mobile platform made repeat measurements every third day at each intersection for 6-10 min at a resolution of 10 s. In two-week periods in both summer and winter seasons, each site was visited 3-4 times, and a temporal adjustment was applied to each dataset. We present the correlations between eight species measured using mobile monitoring and the 2-week PSD data and observe correlations between mobile NOx measurements and PSD NOx measurements in both summer and winter (Pearson's r = 0.84 and 0.48, respectively). The summer season exhibited the strongest correlations between multiple pollutants, whereas the winter had comparatively few statistically significant correlations. In the summer CO was correlated with PSD pentanes (r = 0.81), and PSD NOx was correlated with mobile measurements of black carbon (r = 0.83), two ultrafine particle count measures (r = 0.8), and intermodal (1-3 μm) particle counts (r = 0.73). Principal Component Analysis of the combined PSD and mobile monitoring data revealed multipollutant features consistent with light duty vehicle traffic, diesel exhaust and crankcase blow by. These features were more consistent

  18. Application technology progress report: Evaluation of PM-10 commercial inlets and development of an inlet for new Rocky Flats Plant surveillance air sampler, January 1986-December 1986

    SciTech Connect

    Langer, G.; Deitesfeld, C.A. (ed.0

    1987-09-10

    Work during 1986 was concerned with developing a new PM-10 inlet for use at Rocky Flats Plant (RFP), Golden, Colorado. The commercial units that we evaluated did not allow for recovery of the >10-..mu..m dust fraction as may be required by EPA and DOE for nuclear installations. One of them, the Wedding PM-10 Inlet, did not meet the PM-10 cut-point requirement, because of the build-up of vegetative fibers in the cyclone type separator. Therefore, we developed a new PM-10 inlet (patent applied for) to meet our needs, and especially one that is adaptable to our existing 60 surveillance air samplers at minimum cost. The inlet utilizes a modified slotted impactor design. This device is directly adaptable to existing EPA high-volume samplers. 9 refs., 5 figs., 1 tab.

  19. Characterizing PUF disk passive air samplers for alkyl-substituted PAHs: Measured and modelled PUF-AIR partition coefficients with COSMO-RS.

    PubMed

    Parnis, J Mark; Eng, Anita; Mackay, Donald; Harner, Tom

    2016-02-01

    Isomers of alkyl-substituted polycyclic aromatic hydrocarbons (PAHs) and dibenzothiophenes are modelled with COSMO-RS theory to determine the effectiveness and accuracy of this approach for estimation of isomer-specific partition coefficients between air and polyurethane foam (PUF), i.e., KPUF-AIR. Isomer-specific equilibrium partitioning coefficients for a series of 23 unsubstituted and isomeric alkyl-substituted PAHs and dibenzothiophenes were measured at 22 °C. This data was used to determine the accuracy of estimated values using COSMO-RS, which is isomer specific, and the Global Atmospheric Passive Sampling (GAPS) template approach, which treats all alkyl-substitutions as a single species of a given side-chain carbon number. A recently developed oligomer-based model for PUF was employed, which consisted of a 1:1 condensed pair of 2,4-toluene-diisocyanide and glycerol. The COSMO-RS approach resulted in a significant reduction in the RMS error associated with simple PAHs and dibenzothiophene compared with the GAPS template approach. When used with alkylated PAHs and dibenzothiophenes grouped into carbon-number categories, the GAPS template approach gave lower RMS error (0.72) compared to the COSMO-RS result (0.87) when the latter estimates were averaged within the carbon-number-based categories. When the isomer-specific experimental results were used, the COSMO-RS approach resulted in a 21% reduction in RMS error with respect to the GAPS template approach, with a 0.57 RMS error for all alkylated PAHs and dibenzothiophenes studied. The results demonstrate that COSMO-RS theory is effective in generating isomer-specific PUF-air partition coefficients, supporting the application of PUF-based passive samplers for monitoring and research studies of polycyclic aromatic compounds (PACs) in air. PMID:26692513

  20. Differential atmospheric tritium sampler

    DOEpatents

    Griesbach, O.A.; Stencel, J.R.

    1987-10-02

    An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The moisture then passes through a combustion chamber where hydrogen gas in the form of H/sub 2/ or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

  1. Differential atmospheric tritium sampler

    DOEpatents

    Griesbach, Otto A.; Stencel, Joseph R.

    1990-01-01

    An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The mixture then passes through a combustion chamber where hydrogen gas in the form of H.sub.2 or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

  2. Active Hydrazine Vapor Sampler (AHVS)

    NASA Technical Reports Server (NTRS)

    Young, Rebecca C.; Mcbrearty, Charles F.; Curran, Daniel J.

    1993-01-01

    The Active Hydrazine Vapor Sampler (AHVS) was developed to detect vapors of hydrazine (HZ) and monomethylhydrazine (MMH) in air at parts-per-billion (ppb) concentration levels. The sampler consists of a commercial personal pump that draws ambient air through paper tape treated with vanillin (4-hydroxy-3-methoxybenzaldehyde). The paper tape is sandwiched in a thin cardboard housing inserted in one of the two specially designed holders to facilitate sampling. Contaminated air reacts with vanillin to develop a yellow color. The density of the color is proportional to the concentration of HZ or MMH. The AHVS can detect 10 ppb in less than 5 minutes. The sampler is easy to use, low cost, and intrinsically safe and contains no toxic material. It is most beneficial for use in locations with no laboratory capabilities for instrumentation calibration. This paper reviews the development, laboratory test, and field test of the device.

  3. Development and testing of a new whole air sampler for use on the NASA Global Hawk aircraft during the Airborne Tropical Tropopause Experiment (ATTREX)

    NASA Astrophysics Data System (ADS)

    Navarro, M. A.; Atlas, E. L.; Lueb, R.; Hendershot, R.; Gabbard, S.; Zhu, X.; Pope, L.

    2012-12-01

    A new whole air sampler was developed to study trace gas chemistry in the upper troposphere and lower stratosphere for the Airborne Tropical Tropopause Experiment (ATTREX). The sampler collects up to 90 samples per flight for measurement of a range of hydrocarbons, halocarbons, organic nitrates and solvents. Hydrocarbons and short-lived organic halogen gases play an important role in the chemistry of the of the upper troposphere/lower stratosphere (UT/LS) region. The characterization of these gases not only provides information on air mass sources and transport time scale, but also defines the reactive halogen budget and the conditions for the stratospheric chemistry that affects ozone depletion rates. As part of the transition between troposphere and stratosphere, nonmethane hydrocarbons (NMHC) and halocarbons reach the Tropical Tropopause Layer (TTL) where chemical and physical processes determine their fate. However, very limited data are available regarding composition, seasonality and variability of these gases, since only high altitude aircraft can reach this region of the atmosphere (>13-14 Km). In November 2011, we flew the new whole air sampling system on 2 research flights. A total of 173 samples were collected during flights of approximately 16-24 hours long, which sampled air in the upper troposphere over the tropical Pacific Ocean at altitudes from 14 - 19 km. Measurements of trace gases were done in the University of Miami (UM) laboratory using a combination of gas chromatography with mass spectrometric, flame ionization, and electron capture detectors. This presentation focuses on the design of the new University of Miami-Advanced Whole Air Sample (UM_AWAS), describes the operation of the instrument components, and shows preliminary results of selected hydrocarbon and halogen concentrations in the TTL region.

  4. A diffusive badge sampler for volatile organic compounds in ambient air and determination using a thermal desorption-GC/MS system.

    PubMed

    Yamamoto, Noriko; Matsubasa, Tomoko; Kumagai, Nami; Mori, Sachiko; Suzuki, Koji

    2002-01-15

    A sensitive personal badge sampler packed with Carbopack B for ambient levels of volatile organic compounds and an analytical system using a thermal desorption-preconcentration-GC/MS have been developed. The capacity of the new sampler was sufficient for an 8-h sampling period, and the analytical method was sensitive enough for the measurement of sub-ppb levels for a 2-h sampling period. The samplers were compared to diffusive samplers (OVM 3500) for typical environmental concentrations. There was a good correlation between the results obtained with the new samplers and the OVM samplers.

  5. PCDD, PCDF, dl-PCB and organochlorine pesticides monitoring in São Paulo City using passive air sampler as part of the Global Monitoring Plan.

    PubMed

    Tominaga, M Y; Silva, C R; Melo, J P; Niwa, N A; Plascak, D; Souza, C A M; Sato, M I Z

    2016-11-15

    The persistent organic pollutants (POPs), such as organochlorine pesticides and PCBs, are ordinarily monitored in the aquatic environment or in soil in the environmental quality monitoring programs in São Paulo, Brazil. One of the core matrices proposed in the POPs Global Monitoring Plan (GMP) from the Stockholm Convention list is the ambient air, which is not a usual matrix for POPs monitoring in the country. In this study POP levels were evaluated in the air samples from an urban site in São Paulo City over five years, starting in 2010 as a capacity building project for Latin America and the Caribbean region for POP monitoring in ambient air using passive samplers. Furthermore, after the end of the Project in 2012, the monitoring continued in the same sampling site as means to improving the analytical capacity building and contribute to the GMP data. The POPs monitored were 17 congeners of 2,3,7,8 chloro-substituted PCDDs and PCDFs, dioxin-like PCBs, indicator PCBs, organochlorine pesticides and toxaphene. The results show a slight decrease in PCDD/F, dl-PCBs and indicator PCBs levels along the five years. The organochlorine pesticide endosulfan was present at its highest concentration at the beginning of the monitoring period, but it was below detection level in the last year of the monitoring. Some other organochlorine pesticides were detected close to or below quantitation limits. The compounds identified were dieldrin, chlordane, α-HCH, γ-HCH, heptachlor, heptachlor epoxide, hexachlorobenzene and DDTs. Toxaphene congeners were not detected. These results have confirmed the efficacy of passive sampling for POP monitoring and the capacity building for POP analysis and monitoring was established. However more needs to be done, including expansion of sampling sites, new POPs and studies on sampling rates to be considered in calculating the concentration of POPs in ambient air using a passive sampler. PMID:27487448

  6. PCDD, PCDF, dl-PCB and organochlorine pesticides monitoring in São Paulo City using passive air sampler as part of the Global Monitoring Plan.

    PubMed

    Tominaga, M Y; Silva, C R; Melo, J P; Niwa, N A; Plascak, D; Souza, C A M; Sato, M I Z

    2016-11-15

    The persistent organic pollutants (POPs), such as organochlorine pesticides and PCBs, are ordinarily monitored in the aquatic environment or in soil in the environmental quality monitoring programs in São Paulo, Brazil. One of the core matrices proposed in the POPs Global Monitoring Plan (GMP) from the Stockholm Convention list is the ambient air, which is not a usual matrix for POPs monitoring in the country. In this study POP levels were evaluated in the air samples from an urban site in São Paulo City over five years, starting in 2010 as a capacity building project for Latin America and the Caribbean region for POP monitoring in ambient air using passive samplers. Furthermore, after the end of the Project in 2012, the monitoring continued in the same sampling site as means to improving the analytical capacity building and contribute to the GMP data. The POPs monitored were 17 congeners of 2,3,7,8 chloro-substituted PCDDs and PCDFs, dioxin-like PCBs, indicator PCBs, organochlorine pesticides and toxaphene. The results show a slight decrease in PCDD/F, dl-PCBs and indicator PCBs levels along the five years. The organochlorine pesticide endosulfan was present at its highest concentration at the beginning of the monitoring period, but it was below detection level in the last year of the monitoring. Some other organochlorine pesticides were detected close to or below quantitation limits. The compounds identified were dieldrin, chlordane, α-HCH, γ-HCH, heptachlor, heptachlor epoxide, hexachlorobenzene and DDTs. Toxaphene congeners were not detected. These results have confirmed the efficacy of passive sampling for POP monitoring and the capacity building for POP analysis and monitoring was established. However more needs to be done, including expansion of sampling sites, new POPs and studies on sampling rates to be considered in calculating the concentration of POPs in ambient air using a passive sampler.

  7. Improved correction method for using passive air samplers to assess the distribution of PCNs in the Dongjiang River basin of the Pearl River Delta, South China

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Li, Qilu; Xu, Yue; Luo, Chunling; Liu, Xiang; Li, Jun; Zhang, Gan

    2012-07-01

    An improved correction method was established using passive air samplers to assess the distributions of polychlorinated naphthalenes (PCNs) in the eastern Pearl River Delta, South China. This method was based on a joint correction that used the active air sampling rate and the addition of depuration compounds. As a correction factor, the depuration compounds' properties do not need to be similar to the target compounds. The total PCN air concentrations ranged from 6.4 to 832, with an average of 148 ± 201 pg m-3 in the study area, while the TEQ of the PCNs ranged from 1.2 × 10-4 to 2.6 × 10-2 pg m-3. High concentrations of PCNs were mostly observed in the highly industrialized areas. The PCN air levels were remarkably increased in winter compared with summer. Tri-CNs was the most dominant homologue group, while CN 24 was the most dominant congener. The high proportion of combustion-related PCNs suggests that the contribution of combustion sources to the PCN air burden has been significant recently in comparison with historical emissions.

  8. Immunochemical approach to indoor aeroallergen quantitation with a new volumetric air sampler: studies with mite, roach, cat, mouse, and guinea pig antigens

    SciTech Connect

    Swanson, M.C.; Agarwal, M.K.; Reed, C.E.

    1985-11-01

    We describe a new high-volume air sampler for determining antigen concentrations in homes and illustrate its use for quantitating airborne house dust mite, cat, cockroach, mouse, and guinea pig antigens. The concentration of house dust-mite antigen was similar from houses in Rochester, Minn. and tenement apartments in Harlem, N. Y., but cockroach and mouse urinary proteins were present only in Harlem. The amount of cat or guinea pig antigen varied as expected with the number of pets in the home. In calm air the airborne concentration of mite and cat antigen was similar throughout the house but increased greatly in a bedroom when bedding was changed. In calm air most of the cat and mite antigens were associated with respirable particles less than 5 microns mean aerodynamic mass diameter, but in air sampled after the bedding was changed, more cat antigen was found in particles greater than 5 microns. The apparatus and technique described can provide objective data concerning the magnitude and the relative distribution and duration of suspended particles of defined sizes, which contain allergen activity.

  9. Polyport atmospheric gas sampler

    DOEpatents

    Guggenheim, S. Frederic

    1995-01-01

    An atmospheric gas sampler with a multi-port valve which allows for multi, sequential sampling of air through a plurality of gas sampling tubes mounted in corresponding gas inlet ports. The gas sampler comprises a flow-through housing which defines a sampling chamber and includes a gas outlet port to accommodate a flow of gases through the housing. An apertured sample support plate defining the inlet ports extends across and encloses the sampling chamber and supports gas sampling tubes which depend into the sampling chamber and are secured across each of the inlet ports of the sample support plate in a flow-through relation to the flow of gases through the housing during sampling operations. A normally closed stopper means mounted on the sample support plate and operatively associated with each of the inlet ports blocks the flow of gases through the respective gas sampling tubes. A camming mechanism mounted on the sample support plate is adapted to rotate under and selectively lift open the stopper spring to accommodate a predetermined flow of gas through the respective gas sampling tubes when air is drawn from the housing through the outlet port.

  10. Spatial and seasonal distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls around a municipal solid waste incinerator, determined using polyurethane foam passive air samplers.

    PubMed

    Gao, Lirong; Zhang, Qin; Liu, Lidan; Li, Changliang; Wang, Yiwen

    2014-11-01

    Twenty-six ambient air samples were collected around a municipal solid waste incinerator (MSWI) in the summer and winter using polyurethane foam passive air samplers, and analyzed to assess the spatial and seasonal distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Three stack gas samples were also collected and analyzed to determine PCDD/F (971 pg m(-3) in average) and PCB (2,671 pg m(-3) in average) emissions from the MSWI and to help identify the sources of the pollutants in the ambient air. The total PCDD/F concentrations in the ambient air samples were lower in the summer (472-1,223 fg m(-3)) than the winter (561-3913 fg m(-3)). In contrast, the atmospheric total PCB concentrations were higher in the summer (716-4,902 fg m(-3)) than the winter (489-2,298 fg m(-3)). Principal component analysis showed that, besides emissions from the MSWI, the domestic burning of coal and wood also contributed to the presence of PCDD/Fs and PCBs in the ambient air. The PCDD/F and PCB spatial distributions were analyzed using ordinary Kriging Interpolation and limited effect was found to be caused by emissions from the MSWI. Higher PCDD/F and PCB concentrations were observed downwind of the MSWI than in the other directions, but the highest concentrations were not to be found in the direction with the greatest wind frequency which might be caused by emissions from domestic coal and wood burning. We used a systemic method including sampling and data analysis method which can provide pioneering information for characterizing risks and assessing uncertainty of PCDD/Fs and PCBs in the ambient air around MSWIs in China.

  11. A personal particle speciation sampler.

    PubMed

    Hering, Susanne; Kreisberg, Nathan; John, Walter

    2003-02-01

    Fuller understanding of personal exposures to particulate matter with aerodynamic diameters below 2.5 microm (PM2.5*) requires a personal sampler suitable for assaying not only PM2.5 mass but also its major chemical constituents: elemental carbon, organic carbon, sulfates, and nitrates. The goal to measure these constituents simultaneously imposes several constraints on personal sampler design. The aim of this project was to develop a sampler within these constraints that would be suitable for personal monitoring over 8 hours. In addition, with the intent to improve the precision of mass measurements, we investigated offline use of beta attenuation. The personal particle speciation sampler (PPSS) includes an inlet to remove particles larger than 2.5 microm, 2 sampling channels, and a pump with flow control. One channel serves for measuring particle mass and inorganic ions; the other, for measuring organic carbon and elemental carbon. Denuders can be placed in either channel or both channels. A backup filter can be placed on the denuded channel to collect volatilized particulate nitrate. Two prototype PPSS units were built and tested. The results of both laboratory testing of key PPSS components and a limited field study of the prototype in comparison to an AIHL (Air and Industrial Hygiene Laboratory) cyclone-based sampler are reported. PMID:12670062

  12. Graphene packed needle trap device as a novel field sampler for determination of perchloroethylene in the air of dry cleaning establishments.

    PubMed

    Heidari, Mahmoud; Bahrami, Abdolrahman; Ghiasvand, Ali Reza; Emam, Maryam Rafiei; Shahna, Farshid Ghorbani; Soltanian, Ali Reza

    2015-01-01

    In this paper we describe the application of a needle trap microextraction device packed with graphene nanoplatelets for the sampling and analysis of perchloroethylene in dry cleaning. The study was carried out in two phases. First the parameters for the sampling and analysis of perchloroethylene by NTD were evaluated and optimized in the laboratory. Then the sampler was used to determine the levels of perchloroethylene in a dry-cleaning shop. In the laboratory phase of the study the performance of the NTD packed with the proposed sorbent was examined in a variety of sampling conditions to evaluate the technique. The technique was also compared with NTDs packed with PDMS as well as SPME with Carboxen/PDMS-coated fibers. Both the NTDs and SPME performed better at lower sampling temperatures and relative humidity levels. The post-sampling storage times for a 95% recovery of the analyte were 5, 5 and 3 days for NTD-graphene, NTD-PDMS and SPME-CAR/PDMS respectively. The optimum desorption time was 3 min for NTDs packed with either graphene or PDMS and 1 min for SPME-CAR/PDMS. The limits of detection for the GC/MS detection system were 0.023 and 0.25 ng mL(-1) for NTDs packed with graphene and PDMS and 0.014 ng mL(-1) for SPME coated with CAR/PDMS. In the second stage of the study the evaluated technique was applied to the sampling and analysis of perchloroethylene in dry cleaning. In this environment the performance of the NTD-graphene as a field sampler for PCE was similar to that of the SPME-CA/PDMS, and better than the NIOSH 1003 method which had greater measurement variations. The results show that a NTD packed with carbonic graphene nanoplatelets and used as an active exhaustive sampling technique is effective for determination of VOC and HVOC occupational/environmental pollutants in air.

  13. [Pollen content of the Paris air: comparison of the results obtained by two samplers for the year 2003].

    PubMed

    Distigny, C; Polenne, J P; Bordenave, L; Bex, V; Squinazi, F

    2004-09-01

    During the 2003 season, a second pollen collector has been established in Paris city (Audubon site) to study the representativeness of the initial collector situated on the roof of the Pasteur Institute. The Hygiene Laboratory of Paris followed the pollen counts from the two collectors, during the period going from May to September. Both the samplers are Lanzoni model with a flow rate of 10 l x min(-1). The quantitative results show that no statistical difference exists between the pollen counts obtained from the 2 sites (Mann-Withney test, p > .05). The dominant species are Urticaceae, Poacae and Castenea species for the 2 collectors. Their counts are similar except for Poacae whose results are higher at the Audubon site. The collection period do not take into account the pollen production period of many trees species because of the late installation of the collector on the Audubon site. The results show that the two sites chosen for the study of pollen distribution are comparable. Nevertheless, the comparative study should be maintained on the next year to get more details about the observed differences and to collect the early trees pollen.

  14. [Pollen content of the Paris air: comparison of the results obtained by two samplers for the year 2003].

    PubMed

    Distigny, C; Polenne, J P; Bordenave, L; Bex, V; Squinazi, F

    2004-09-01

    During the 2003 season, a second pollen collector has been established in Paris city (Audubon site) to study the representativeness of the initial collector situated on the roof of the Pasteur Institute. The Hygiene Laboratory of Paris followed the pollen counts from the two collectors, during the period going from May to September. Both the samplers are Lanzoni model with a flow rate of 10 l x min(-1). The quantitative results show that no statistical difference exists between the pollen counts obtained from the 2 sites (Mann-Withney test, p > .05). The dominant species are Urticaceae, Poacae and Castenea species for the 2 collectors. Their counts are similar except for Poacae whose results are higher at the Audubon site. The collection period do not take into account the pollen production period of many trees species because of the late installation of the collector on the Audubon site. The results show that the two sites chosen for the study of pollen distribution are comparable. Nevertheless, the comparative study should be maintained on the next year to get more details about the observed differences and to collect the early trees pollen. PMID:15529829

  15. Use of passive samplers to detect organochlorine pesticides in air and water at wetland mountain region sites (S-SE Brazil).

    PubMed

    Meire, Rodrigo Ornellas; Khairy, Mohammed; Targino, Admir Créso; Galvão, Petrus Magnus Amaral; Torres, Joåo Paulo Machado; Malm, Olaf; Lohmann, Rainer

    2016-02-01

    Low-density polyethylene (LDPE) passive samplers were deployed in upland surface waters and the overlying atmosphere during May and June 2012, to determine the transport and trends of freely dissolved and gaseous organochlorine pesticides (OCPs) along altitudinal gradients in mountain regions in south and southeast Brazil. Gaseous OCP concentrations were dominated by hexachlorobenzene (3.0-29 pg m(-3)) and endosulfans (Ʃ = α-endosulfan + β-endosulfan + endosulfan sulphate, 170-260 pg m(-3)), whereas freely dissolved endosulfans were significantly higher than all other OCPs (p < 0.001). The presence of some target pesticides at the highest elevation sites indicated their efficient high-altitude transport from regional sources. Air-water exchange gradients indicated net deposition of most volatile and recently banned OCPs (e.g., HCB, endosulfan) over Brazilian mountains. Moreover, the exposure of these sites to large-scale continental airflows with varying source contributions may partly explain the atmospheric deposition of selected OCPs over upland freshwaters at tropical and subtropical mountains sites in Brazil. These findings, coupled with LDPE passive air and water sampling measurements, point out the potential inputs from distant sources of semi-volatile chemicals to the two high-altitude sites.

  16. Spatial trends, sources, and air-water exchange of organochlorine pesticides in the Great Lakes basin using low density polyethylene passive samplers.

    PubMed

    Khairy, Mohammed; Muir, Derek; Teixeira, Camilla; Lohmann, Rainer

    2014-08-19

    Polyethylene passive samplers were deployed during summer and fall of 2011 in the lower Great Lakes to assess the spatial distribution and sources of gaseous and freely dissolved organochlorine pesticides (OCPs) and their air-water exchange. Average gaseous OCP concentrations ranged from nondetect to 133 pg/m(3). Gaseous concentrations of hexachlorobenzene, dieldrin, and chlordanes were significantly greater (Mann-Whitney test, p < 0.05) at Lake Erie than Lake Ontario. A multiple linear regression implied that both cropland and urban areas within 50 and 10 km buffer zones, respectively, were critical parameters to explain the total variability in atmospheric concentrations. Freely dissolved OCP concentrations (nondetect to 114 pg/L) were lower than previously reported. Aqueous half-lives generally ranged from 1.7 to 6.7 years. Nonetheless, concentrations of p,p'-DDE and chlordanes were higher than New York State Ambient Water Quality Standards for the protection of human health from the consumption of fish. Spatial distributions of freely dissolved OCPs in both lakes were influenced by loadings from areas of concern and the water circulation patterns. Flux calculations indicated net deposition of γ-hexachlorocyclohexane, heptachlor-epoxide, and α- and β-endosulfan (-0.02 to -33 ng/m(2)/day) and net volatilization of heptachlor, aldrin, trans-chlordane, and trans-nonachlor (0.0 to 9.0 ng/m(2)/day) in most samples.

  17. Summary of stationary and personal air sampling measurements made during a plutonium glovebox decommissioning project.

    SciTech Connect

    Munyon, W. J.; Lee, M. B.

    2002-02-01

    Workplace air sampling was performed during the decommissioning of a previously active plutonium glovebox facility located at Argonne National Laboratory. Personal air samplers (PAS) were used to measure breathing zone activity concentrations of workers engaged in size-reducing contaminated gloveboxes. Stationary air samplers (SAS) were used to measure the work area activity concentrations and test their application in providing representative sampling of breathing zone activity concentrations. The relative response of these samplers (PAS:SAS) was tracked during the course of the decommissioning work, with results yielding favorable agreement to within a factor of {+-}5. A cascade impactor was used to determine the particle size distribution of workplace aerosols. The average activity median aerodynamic diameter (AMAD) was estimated to be 3.0 {mu}m, with a corresponding geometric standard deviation of 2.4. A gas-flow proportional counter was utilized to measure the gross alpha activity collected on both the SAS glass fiber and the PAS cellulose fiber filters. A subset of this filter group was subsequently analyzed using an alpha spectrometer post radiochemical processing and isotopic separation. The quantity of alpha activity measured on the SAS filters was generally within {+-}30% of the alpha spectrometry measurements. However, measurements made of the activity present on the PAS cellulose fiber filters were consistently underestimated using a gas-flow proportional counter, suggesting a small correction factor of 15-20% to account for the absorption of alpha particle emissions.

  18. Summary of stationary and personal air sampling measurements made during a plutonium glovebox decommissioning project.

    PubMed

    Munyon, W J; Lee, M B

    2002-02-01

    Workplace air sampling was performed during the decommissioning of a previously active plutonium glovebox facility located at Argonne National Laboratory. Personal air samplers (PAS) were used to measure breathing zone activity concentrations of workers engaged in size-reducing contaminated gloveboxes. Stationary air samplers (SAS) were used to measure the work area activity concentrations and test their application in providing representative sampling of breathing zone activity concentrations. The relative response of these samplers (PAS:SAS) was tracked during the course of the decommissioning work, with results yielding favorable agreement to within a factor of +/-5. A cascade impactor was used to determine the particle size distribution of workplace aerosols. The average activity median aerodynamic diameter (AMAD) was estimated to be 3.0 microm, with a corresponding geometric standard deviation of 2.4. A gas-flow proportional counter was utilized to measure the gross alpha activity collected on both the SAS glass fiber and the PAS cellulose fiber filters. A subset of this filter group was subsequently analyzed using an alpha spectrometer post radiochemical processing and isotopic separation. The quantity of alpha activity measured on the SAS filters was generally within +/-30% of the alpha spectrometry measurements. However, measurements made of the activity present on the PAS cellulose fiber filters were consistently underestimated using a gas-flow proportional counter, suggesting a small correction factor of 15-20% to account for the absorption of alpha particle emissions.

  19. Polycyclic Aromatic Hydrocarbons in Indoor Air and EnvironmentalTobacco Smoke Measured with a New Integrated Organic Vapor-ParticleSampler

    SciTech Connect

    Gundel, L.A.; Daisey, J.M.; Mahanama, K.R.R.; Lee, C.C.; Stevens,R.K.

    1993-01-01

    Sampling details. The novel aspect of the sampling equipment is the use of ground XAD-4 resin as a coating for annular denuders. Figure 1 shows a schematic diagram of one sampling configuration used for field testing the IOVPS in indoor air and ETS. Commercially available, single-channel glass denuders, 22 cm long, with a 1 mm annulus (University Research Glass, Carrboro, NC, USA were used with a Teflon- ) lined aluminum cyclone (cutoff 2.5 microns at 10 L mine ) preceding the first denuder. Three XAD-4-coated denuders were connected in series between the cyclone and a Teflon filter pack which contained a pre-extracted and pre-weighed Teflon-coated glass-fiber filter. (The three-denuder configuration was used for determining breakthrough of naphthalene and its methyl derivatives as a function of flow rate.) In some experiments, a coated denuder followed the filter pack. The parallel sorbent bed sampler used an aluminum open-face filter holder with a Teflon-coated glass-fiber filter, followed by a glass tube packed with 2.5 g cleaned XAD-4 resin. Flow rates, measured with a dry gas test meter, were 5, 10 and 20 L min-1 for field testing; sampling times varied from 3 to 22 hours. Indoor air with no combustion sources was sampled in an unoccupied room. Diluted sidestream smoke was sampled as a surrogate for ETS in an unventilated 20 m3 chamber at 5 L rnin-l for hour-long periods while a single-port smoking machine smoked 3 cigarettes. Ambient temperature varied between 22 and 26 C.

  20. Preliminary assessment of using tree-tissue analysis and passive-diffusion samplers to evaluate trichloroethene contamination of ground water at Site SS-34N, McChord Air Force Base, Washington, 2001

    USGS Publications Warehouse

    Cox, S.E.

    2002-01-01

    Two low-cost innovative sampling procedures for characterizing trichloroethene (TCE) contamination in ground water were evaluated for use at McChord Air Force Base (AFB) by the U.S. Geological Survey, in cooperation with the U.S. Air Force McChord Air Force Base Installation Restoration Program, in 2001. Previous attempts to characterize the source of ground-water contamination in the heterogeneous glacial outwash aquifer at McChord site SS-34N using soil-gas surveys, direct-push exploration, and more than a dozen ground-water monitoring wells have had limited success. The procedures assessed in this study involved analysis of tree-tissue samples to map underlying ground-water contamination and deploying passive-diffusion samplers to measure TCE concentrations in existing monitoring wells. These procedures have been used successfully at other U.S. Department of Defense sites and have resulted in cost avoidance and accelerated site characterization. Despite the presence of TCE in ground water at site SS-34N, TCE was not detected in any of the 20 trees sampled at the site during either early spring or late summer sampling. The reason the tree tissue procedure was not successful at the McChord AFB site SS-34N may have been due to an inability of tree roots to extract moisture from a water table 30 feet below the land surface, or that concentrations of TCE in ground water were not large enough to be detectable in the tree tissue at the sampling point. Passive-diffusion samplers were placed near the top, middle, and bottom of screened intervals in three monitoring wells and TCE was observed in all samplers. Concentrations of TCE from the passive-diffusion samplers were generally similar to concentrations found in samples collected in the same wells using conventional pumping methods. In contrast to conventional pumping methods, the collection of ground-water samples using the passive-diffusion samples did not generate waste purge water that would require hazardous

  1. Observations on persistent organic pollutants in plants: Implications for their use as passive air samplers and for POP cycling

    SciTech Connect

    Ockenden, W.A.; Parker, C.; Jones, K.C.; Steinnes, E.

    1998-09-15

    Pine Needle (Pinus sylvestris) and lichen (Hypogymnia physodes) samples from various remote sites across Norway have been analyzed for a range of persistent organic pollutants (POPs). Results have shown differences in accumulation between species, with higher concentrations being noted in the H. physodes than the P. sylvestris. This indicates that to use vegetation as a biomonitor, intraspecies and not interspecies comparisons in vegetation pollutant loading between sites are necessary. {alpha}/{gamma}-HCH ratios were highest at colder northern sites, indicating increased distance from source areas and long-range atmospheric transport. Concentrations of PCBs 101, 118, 138, and 153 in H. physodes were found to be higher at lower temperatures. Trends between burdens of the other POPs in H. physodes or P. sylvestris and site temperature or latitude were not apparent. Plant/air partition coefficients indicate favored accumulation of PCBs in vegetation at lower temperatures and for higher chlorinated congeners.

  2. South Philadelphia Passive Sampler and Sensor Study

    EPA Science Inventory

    Starting in June 2013, the United States Environmental Protection Agency (U.S. EPA) and the City of Philadelphia Air Measurements Services began collaborative research on the use of passive samplers (PSs) and stand-alone air measurement (SAM) systems to improve information on the...

  3. A comparison of X-ray fluorescence and wet chemical analysis for lead on air filters from different personal samplers used in a bronze foundry.

    PubMed

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

    2005-06-01

    Portable X-ray fluorescence (XRF) technology may provide faster turn-around without compromising accuracy when assessing personal exposures to metals such as lead, but it has only been tested in limited field environments. This study is part of a series, where different sampler types are used to collect airborne lead in different environments for presentation to a portable XRF analyzer. In this case personal samples were taken at a bronze foundry where lead is added to an alloy of copper, zinc and iron to improve casting, using the closed-face 37 mm cassette, 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. Following XRF analysis the samples were extracted with acid and analyzed by inductively coupled plasma optical emission spectroscopy (ICP). For lead, all five samplers gave correlations (r(2)) greater than 0.9 between the two analytical methods over the entire range of found lead mass, which encompassed both the action level and the permissible exposure limit enforced in the USA by the Occupational Safety and Health Administration (OSHA). However, a correction was required to adjust linear regression trendlines to give a 1 : 1 correlation for the average of three readings across the GSP sampler, and a similar correction was required for the single readings from the IOM sampler and the 25 mm filter cassette. The bias possibly is due to interference from other metals, possibly copper which can absorb the fluorescent radiation of lead. In the case of the Button sampler, the bias is larger, indicating a further source of error, perhaps due to the thickness of the deposit. However, in all cases, correction of the lead results did not greatly affect the overall percentage of samples where the XRF result was within 25% of the ICP result, although it did improve the overall accuracy of the results. The

  4. A comparison study of atmospheric polycyclic aromatic hydrocarbons in three Indian cities using PUF disk passive air samplers

    NASA Astrophysics Data System (ADS)

    Cheng, Hairong; Deng, Zongming; Chakraborty, Paromita; Liu, Di; Zhang, Ruijie; Xu, Yue; Luo, Chunlin; Zhang, Gan; Li, Jun

    2013-07-01

    A passive air sampling campaign was conducted to measure polycyclic aromatic hydrocarbons (PAHs) in Kolkata, Mumbai and Chennai, the three major cities of India. The measured total PAH concentrations ranged from 6480 to 54,800 ng sample-1, comparable to the highest levels across the globe. Three- to four-ring PAHs were the dominant components in the atmosphere. According to the spatial distribution, the PAH concentrations were the highest in Kolkata and the lowest in Chennai. Kolkata and Mumbai were characterized by a relatively high proportion of HMW (high molecular weight) PAHs, which can be ascribed to the difference in the economic and energy structures in the urban areas. Surprisingly, there was not significant decrease in PAH concentrations from urban to rural sites. Rural sources, generally associated with traditional biomass combustion, could be as important as urban sources in India. In this study, the total BaPeq (BaP toxic equivalent) concentrations generally exceeded the human exposure limit, posing potential risk to the health of the local residents.

  5. Determining air-water exchange, spatial and temporal trends of freely dissolved PAHs in an urban estuary using passive polyethylene samplers.

    PubMed

    Lohmann, Rainer; Dapsis, Meredith; Morgan, Eric J; Dekany, Victoria; Luey, Pamela J

    2011-04-01

    Passive polyethylene (PE) samplers were deployed at six locations within Narragansett Bay (RI, USA) to determine sources and trends of freely dissolved and gas-phase polycyclic aromatic hydrocarbons (PAHs) from May to November 2006. Freely dissolved aqueous concentrations of PAHs were dominated by fluoranthene, pyrene, and phenanthrene, at concentrations ranging from tens to thousands of pg/L. These were also the dominant PAHs in the gas phase, at hundreds to thousands of pg/m3. All stations mostly followed the same temporal trends, with highest concentrations (up to 7300 pg/L for sum PAHs) during the second of 11 deployments, coinciding with a major rainstorm. Strong correlations of sum PAHs with river flows and wastewater treatment plant discharges highlighted the importance of rainfall in mobilizing PAHs from a combination of runoff and atmospheric washout. PAH concentrations declined through consecutive deployments III to V, which could be explained by an exponential decay due to flushing with cleaner ocean water during tides. The estimated residence time (tres) of the PAH pulse was 24 days, close to an earlier estimate of tres of 26 days for freshwater in the Bay. Air-water exchange gradients indicated net volatilization of most PAHs closest to Providence. Further south in the Bay, gradients had changed to mostly net uptake of the more volatile PAHs, but net volatilization for the less volatile PAHs. Based on characteristic PAH ratios, freely dissolved PAHs at most sites originated from the combustion of fossil fuels; only two sites were at times affected by fuel spill-derived PAHs. PMID:21351793

  6. Environmental Curiosity Sampler.

    ERIC Educational Resources Information Center

    Stehney, Virginia A.

    The Sampler is designed to stimulate teachers, parents, students, and groups to look at various types of open spaces and facilities as resources for environmental study. Written for use with children, but adaptable to older groups, the Sampler tries to engage the feelings as well as intellects of its users in the process of inquiry. It locates…

  7. A passive sampler for airborne formaldehyde

    NASA Astrophysics Data System (ADS)

    Grosjean, Daniel; Williams, Edwin L.

    A simple, inexpensive passive sampler is described that is capable of reliable measurements of formaldehyde at the parts per billion (ppb) levels relevant to indoor and outdoor air quality. The passive sampler consists of a modified dual filter holder in which the upper stage serves as the diffusion barrier, the lower stage includes a 2,4-dinitrophenylhydrazine (DNPH)-coated filter which collects formaldehyde, and the space between the two stages serve as the diffusion gap. The measured sampling rate, 18.8 ± 1.8 ml min -1, was determined in experiments involving sampling of ppb levels of formaldehyde with the passive sampler and with DNPH-coated C 18 cartridges and agrees well with the value of 19.4 ± 2.0 ml min -1 calculated from theory. The measured sampling rate was independent of formaldehyde concentration (16-156 ppb) and sampling duration (1.5-72 h). The precision of the measurements for colocated passive samplers averaged 8.6% in purified and indoor air (office and museums) and 10.2% in photochemically polluted outdoor air. With a 1.2-μm pore size Teflon filter as the diffusion barrier, the detection limit is 32 ppb h, e.g. 4 ppb in an 8-h sample, 1.3 ppb in a 24-h sample, and so on. Perceived advantages and limitations of the sampler are discussed including flexibility, cost effectiveness and possible negative bias at high ambient levels of ozone.

  8. A personal dust sampler simulating variable human lung function.

    PubMed Central

    Kucharski, R

    1980-01-01

    In a prototype of a new personal dust sampling system (PDS) the speed of air sampling in the breathing zone is related to the pulmonary ventilation rate of the wearer, using the correlation between pulmonary ventilation and pulse rate that is monitored by electrodes fastened on the sampler wearer's chest. The method of calibration and the results of dust chamber and field measurements are presented. The prototype of the new sampler was tested in a lead and zinc smelting plant against a routine stationary sampler and typical personal sampler. Personal exposure using all the above mentioned devices has also been assessed, and the PDS gives satisfactory results in use. PMID:7426470

  9. Evaluation of three portable samplers for monitoring airborne fungi

    NASA Technical Reports Server (NTRS)

    Mehta, S. K.; Mishra, S. K.; Pierson, D. L.

    1996-01-01

    Airborne fungi were monitored at five sample sites with the Burkard portable, the RCS Plus, and the SAS Super 90 air samplers; the Andersen 2-stage impactor was used for comparison. All samplers were calibrated before being used simultaneously to collect 100-liter samples at each site. The Andersen and Burkard samplers retrieved equivalent volumes of airborne fungi; the SAS Super 90 and RCS Plus measurements did not differ from each other but were significantly lower than those obtained with the Andersen or Burkard samplers. Total fungal counts correlated linearly with Cladosporium and Penicillium counts. Alternaria species, although present at all sites, did not correlate with total count or with amounts of any other fungal genera. Sampler and location significantly influenced fungal counts, but no interactions between samplers and locations were found.

  10. The Gibbs Centroid Sampler

    SciTech Connect

    Thompson, William A.; Newberg, Lee A.; Conlan, Sean; McCue, Lee Ann; Lawrence, Charles E.

    2007-07-01

    The Gibbs Centroid Sampler is a software package designed for locating conserved elements in biopolymer sequences. The Gibbs Centroid Sampler reports a centroid alignment, i.e., an alignment that has the minimum total distance to the set of samples chosen from the a posteriori probability distribution of transcription factor binding site alignments. In so doing, it garners information from the full ensemble of solutions, rather than only the single most probable point that is the target of many motif finding algorithms, including its predecessor, the Gibbs Recursive Sampler. Centroid estimators have been shown to yield substantial improvements, in both sensitivity and positive predictive values, to the prediction of RNA secondary structure and motif finding. The Gibbs Centroid Sampler, along with interactive tutorials, an online user manual, and information on downloading the software, is available at http://bayesweb.wadsworth.org/gibbs/gibbs.html.

  11. 6S Return Samples: Assessment of Air Quality in the International Space Station (ISS) Based on Solid Sorbent Air Sampler (SSAS) and Formaldehyde Monitoring Kit (FMK) Analyses

    NASA Technical Reports Server (NTRS)

    James, John T.

    2004-01-01

    The toxicological assessments of SSAS and FMK analytical results are reported. Analytical methods have not changed from earlier reports. Surrogate standard recoveries from the SSAS tubes were 66-76% for 13C-acetone, 85-96% for fluorobenzene, and 73-89% for chlorobenzene. Post-flight flows were far below pre-flight flows and an investigation of the problem revealed that the reduced flow was caused by a leak at the interface of the pump inlet tube and the pump head. This resulted in degradation of pump efficiency. Further investigation showed that the problem occurred before the SSAS was operated on orbit and that use of the post-flight flows yielded consistent and useful results. Recoveries from formaldehyde control badges were 86 to 104%. The two general criteria used to assess air quality are the total-non-methane-volatile organic hydrocarbons (NMVOCs) and the total T-value (minus the CO2 and formaldehyde contributions). The T values will not be reported for these data due to the flow anomaly. Control of atmospheric alcohols is important to the water recovery system engineers, hence total alcohols (including acetone) are also shown for each sample. Octafluoropropane (OFP) is not efficiently trapped by the sorbents used in the SSAS. Because formaldehyde is quantified from sorbent badges, its concentration is also listed separately. These five indices of air quality are summarized.

  12. USE OF PASSIVE SAMPLERS IN THE DEARS

    EPA Science Inventory

    The Detroit Exposure and Aerosol Research Study (DEARS) employs a number of passive diffusion-based samplers for the collection of select gaseous air pollutants. These pollutants include criteria gases such as ozone, carbonyls such as acrolein, and volatile organics such as 1-3, ...

  13. Ford Partnership for Advanced Studies (Ford PAS)

    ERIC Educational Resources Information Center

    Carrier, Cheryl

    2006-01-01

    This article features the Ford Partnership for Advanced Studies (Ford PAS) program that helps students gain knowledge about real-life business issues. Ford PAS is an educational program that combines college-prep academics with the critical 21st century skills students will need to succeed in college and in the workplace. The Ford PAS program uses…

  14. Monitoring of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of southern Luxembourg using XAD-2 resin-based passive samplers.

    PubMed

    Schummer, Claude; Appenzeller, Brice M; Millet, Maurice

    2014-02-01

    XAD-2 resin-based passive samplers (PAS) with dimensions adapted to 100 mL accelerated solvent extraction cells were used to study the temporal and spatial variations of 17 PAHs on five sites in the atmosphere of southern Luxembourg. This new design allowed extracting the PAS without emptying the resin from the shelter. PAH analyses were done with gas chromatography-tandem mass spectrometry. PAS were deployed for 1 year with varying sampling periodicities, and 16 PAHs were detected with concentrations ranging from 1 ng/PAS for chrysene to 9,727 ng/PAS for naphthalene. The PAS were found adapted to the monitoring of temporal and spatial variations for lightweight PAHs (up to four aromatic rings) though not for heavy PAHs with five aromatic rings or more, as these compounds are preferably in the particle phase of the atmosphere and the amount of these PAHs trapped on the PAS will be too low.

  15. Environmental Awareness Sampler.

    ERIC Educational Resources Information Center

    Halnen, Andrew; And Others

    This sampler for teachers provides information for initiating and dealing with environmental studies in the classroom. Utilizing an interdisciplinary approach, behavioral objectives related to environmental awareness are listed for social studies, science, mathematics, language arts, health, physical education, recreation, music, and local…

  16. Design and validation of a passive deposition sampler

    PubMed Central

    Yu, Chang-Ho; Mainelis, Gediminas; Chen, Lung Chi; Weisel, Clifford P.; Lioy, Paul J.

    2014-01-01

    A new, passive particle deposition air sampler, called the Einstein–Lioy Deposition Sampler (ELDS), has been developed to fill a gap in passive sampling for near-field particle emissions. The sampler can be configured in several ways: with a protective hood for outdoor sampling, without a protective hood, and as a dust plate. In addition, there is an XRF-ready option that allows for direct sampling onto a filter-mounted XRF cartridge which can be used in conjunction with all configurations. A wind tunnel was designed and constructed to test the performance of different sampler configurations using a test dust with a known particle size distribution. The sampler configurations were also tested versus each other to evaluate whether or not the protective hood would affect the collected particle size distribution. A field study was conducted to test the sampler under actual environmental conditions and to evaluate its ability to collect samples for chemical analysis. Individual experiments for each configuration demonstrated precision of the sampler. The field experiment demonstrated the ability of the sampler to both collect mass and allow for the measurement of an environmental contaminant i.e. Cr6+. The ELDS was demonstrated to be statistically not different for Hooded and Non-Hooded models, compared to each other and the test dust; thus, it can be used indoors and outdoors in a variety of configurations to suit the user's needs. PMID:22820464

  17. South Philadelphia Passive Sampler and Sensor Study - Interim Report

    EPA Science Inventory

    Starting in the June 2013, the U.S. EPA and the City of Philadelphia Air Measurements Services (AMS) began a collaborative research project to investigate how sensor-based, stand-alone air measurements (SAMs) and passive samplers (PSs) can help improve information on air pollutan...

  18. Efficiency tests of samplers for microbiological aerosols, a review

    NASA Technical Reports Server (NTRS)

    Henningson, E.; Faengmark, I.

    1984-01-01

    To obtain comparable results from studies using a variety of samplers of microbiological aerosols with different collection performances for various particle sizes, methods reported in the literature were surveyed, evaluated, and tabulated for testing the efficiency of the samplers. It is concluded that these samplers were not thoroughly tested, using reliable methods. Tests were conducted in static air chambers and in various outdoor and work environments. Results are not reliable as it is difficult to achieve stable and reproducible conditions in these test systems. Testing in a wind tunnel is recommended.

  19. Radial diffusive samplers for determination of 8-h concentration of BTEX, acetone, ethanol and ozone in ambient air during a sea breeze event

    NASA Astrophysics Data System (ADS)

    Roukos, Joelle; Locoge, Nadine; Sacco, Paolo; Plaisance, Hervé

    2011-01-01

    The radial diffusive sampler Radiello ® filled with Carbograph 4 was evaluated for monitoring BTEX, ethanol and acetone concentrations for 8-hour exposure time. The sampling rates were first evaluated in an exposure chamber under standard conditions. Benzene and toluene showed the highest sampling rates with satisfactory standard deviations. Ethylbenzene and xylenes showed medium sampling rates but higher standard deviations that can be attributed to a low affinity of these compounds with the adsorbent medium for short sampling time. Acetone has a fair result because of the increase of its partial pressure in the vicinity of the adsorbent surface in the course of sampling. The Carbograph 4 adsorbent does not seem to be suitable for sampling ethanol, likely because of its high volatility. The influences of three environmental factors (temperature (T), relative humidity (RH) and concentration level (C)) on the sampling rates were also evaluated, following a fractional factorial design at two factor levels (low and high). Results were only investigated on benzene, toluene and acetone. Temperature and relative humidity are found to be the most important factors leading to variability of the benzene and toluene sampling rates. The applicability of the sampler for 8-hour sampling was demonstrated by the results of a measurement campaign carried out during a sea breeze event. Mapping of benzene, toluene and acetone concentrations showed the highest concentrations in the industrial zone following the wind direction coming from the North. Nevertheless, the sea breeze tends to reduce the spread of the industrial plumes. On the contrary, the ozone map presents the lowest concentrations at the same industrial area indicating a net consumption of ozone. The highest ozone concentrations were found in the southeastern zone suggesting a local ozone formation.

  20. Variable depth core sampler

    DOEpatents

    Bourgeois, P.M.; Reger, R.J.

    1996-02-20

    A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

  1. Variable depth core sampler

    DOEpatents

    Bourgeois, Peter M.; Reger, Robert J.

    1996-01-01

    A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

  2. High speed transient sampler

    DOEpatents

    McEwan, T.E.

    1995-11-28

    A high speed sampler comprises a meandered sample transmission line for transmitting an input signal, a straight strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates along the transmission lines. The sampling gates comprise a four terminal diode bridge having a first strobe resistor connected from a first terminal of the bridge to the positive strobe line, a second strobe resistor coupled from the third terminal of the bridge to the negative strobe line, a tap connected to the second terminal of the bridge and to the sample transmission line, and a sample holding capacitor connected to the fourth terminal of the bridge. The resistance of the first and second strobe resistors is much higher than the signal transmission line impedance in the preferred system. This results in a sampling gate which applies a very small load on the sample transmission line and on the strobe generator. The sample holding capacitor is implemented using a smaller capacitor and a larger capacitor isolated from the smaller capacitor by resistance. The high speed sampler of the present invention is also characterized by other optimizations, including transmission line tap compensation, stepped impedance strobe line, a multi-layer physical layout, and unique strobe generator design. A plurality of banks of such samplers are controlled for concatenated or interleaved sample intervals to achieve long sample lengths or short sample spacing. 17 figs.

  3. High speed transient sampler

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    A high speed sampler comprises a meandered sample transmission line for transmitting an input signal, a straight strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates along the transmission lines. The sampling gates comprise a four terminal diode bridge having a first strobe resistor connected from a first terminal of the bridge to the positive strobe line, a second strobe resistor coupled from the third terminal of the bridge to the negative strobe line, a tap connected to the second terminal of the bridge and to the sample transmission line, and a sample holding capacitor connected to the fourth terminal of the bridge. The resistance of the first and second strobe resistors is much higher than the signal transmission line impedance in the preferred system. This results in a sampling gate which applies a very small load on the sample transmission line and on the strobe generator. The sample holding capacitor is implemented using a smaller capacitor and a larger capacitor isolated from the smaller capacitor by resistance. The high speed sampler of the present invention is also characterized by other optimizations, including transmission line tap compensation, stepped impedance strobe line, a multi-layer physical layout, and unique strobe generator design. A plurality of banks of such samplers are controlled for concatenated or interleaved sample intervals to achieve long sample lengths or short sample spacing.

  4. Computational fluid dynamics (CFD) simulation of a newly designed passive particle sampler.

    PubMed

    Sajjadi, H; Tavakoli, B; Ahmadi, G; Dhaniyala, S; Harner, T; Holsen, T M

    2016-07-01

    In this work a series of computational fluid dynamics (CFD) simulations were performed to predict the deposition of particles on a newly designed passive dry deposition (Pas-DD) sampler. The sampler uses a parallel plate design and a conventional polyurethane foam (PUF) disk as the deposition surface. The deposition of particles with sizes between 0.5 and 10 μm was investigated for two different geometries of the Pas-DD sampler for different wind speeds and various angles of attack. To evaluate the mean flow field, the k-ɛ turbulence model was used and turbulent fluctuating velocities were generated using the discrete random walk (DRW) model. The CFD software ANSYS-FLUENT was used for performing the numerical simulations. It was found that the deposition velocity increased with particle size or wind speed. The modeled deposition velocities were in general agreement with the experimental measurements and they increased when flow entered the sampler with a non-zero angle of attack. The particle-size dependent deposition velocity was also dependent on the geometry of the leading edge of the sampler; deposition velocities were more dependent on particle size and wind speeds for the sampler without the bend in the leading edge of the deposition plate, compared to a flat plate design. Foam roughness was also found to have a small impact on particle deposition.

  5. Computational fluid dynamics (CFD) simulation of a newly designed passive particle sampler.

    PubMed

    Sajjadi, H; Tavakoli, B; Ahmadi, G; Dhaniyala, S; Harner, T; Holsen, T M

    2016-07-01

    In this work a series of computational fluid dynamics (CFD) simulations were performed to predict the deposition of particles on a newly designed passive dry deposition (Pas-DD) sampler. The sampler uses a parallel plate design and a conventional polyurethane foam (PUF) disk as the deposition surface. The deposition of particles with sizes between 0.5 and 10 μm was investigated for two different geometries of the Pas-DD sampler for different wind speeds and various angles of attack. To evaluate the mean flow field, the k-ɛ turbulence model was used and turbulent fluctuating velocities were generated using the discrete random walk (DRW) model. The CFD software ANSYS-FLUENT was used for performing the numerical simulations. It was found that the deposition velocity increased with particle size or wind speed. The modeled deposition velocities were in general agreement with the experimental measurements and they increased when flow entered the sampler with a non-zero angle of attack. The particle-size dependent deposition velocity was also dependent on the geometry of the leading edge of the sampler; deposition velocities were more dependent on particle size and wind speeds for the sampler without the bend in the leading edge of the deposition plate, compared to a flat plate design. Foam roughness was also found to have a small impact on particle deposition. PMID:27108045

  6. Vacuum probe surface sampler

    NASA Technical Reports Server (NTRS)

    Zahlava, B. A. (Inventor)

    1973-01-01

    A vacuum probe surface sampler is described for rapidly sampling relatively large surface areas which possess relatively light loading densities of micro-organism, drug particles or the like. A vacuum head with a hollow handle connected to a suitable vacuum source is frictionally attached to a cone assembly terminating in a flared tip adapted to be passed over the surface to be sampled. A fine mesh screen carried by the vacuum head provides support for a membrane filter which collects the microorganisms or other particles. The head assembly is easily removed from the cone assembly without contacting the cone assembly with human hands.

  7. South Philadelphia Passive Sampler and Sensor Study: Interim Report

    EPA Science Inventory

    Starting in June 2013, the United States Environmental Protection Agency (U.S. EPA) and the City of Philadelphia Air Measurements Services began collaborative research on the use of passive samplers (PSs) and stand-alone air measurement (SAM) systems to improve information on the...

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

    PubMed

    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. Surface Contamination by FTIR-PAS

    NASA Astrophysics Data System (ADS)

    Davis, Dennis M.; Hoffland, Lynn D.

    1985-12-01

    Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) is used to study the contamination of alkyd painted panels by liquids and solids. These alkyd painted panels are stainless steel panels coated with primer and an alkyd resin based paint which the Army uses for its vehicles. Portions of these panels were contaminated by dimethyl methyl phosphonate, tri-(2-ethylhexyl) phosphate, and triphenyl phosphate. The panels were then studied using FTIR-PAS, and the spectra identified.

  10. Laser pulse sampler

    DOEpatents

    Vann, C.

    1998-03-24

    The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera. 5 figs.

  11. Laser pulse sampler

    DOEpatents

    Vann, Charles

    1998-01-01

    The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera.

  12. Waveform Sampler CAMAC Module

    SciTech Connect

    Freytag, D.R.; Haller, G.M.; Kang, H.; Wang, J.

    1985-09-01

    A Waveform Sampler Module (WSM) for the measurement of signal shapes coming from the multi-hit drift chambers of the SLAC SLC detector is described. The module uses a high speed, high resolution analog storage device (AMU) developed in collaboration between SLAC and Stanford University. The AMU devices together with high speed TTL clocking circuitry are packaged in a hybrid which is also suitable for mounting on the detector. The module is in CAMAC format and provides eight signal channels, each recording signal amplitude versus time in 512 cells at a sampling rate of up to 360 MHz. Data are digitized by a 12-bit ADC with a 1 ..mu..s conversion time and stored in an on-board memory accessible through CAMAC.

  13. Parallel optical sampler

    DOEpatents

    Tauke-Pedretti, Anna; Skogen, Erik J; Vawter, Gregory A

    2014-05-20

    An optical sampler includes a first and second 1.times.n optical beam splitters splitting an input optical sampling signal and an optical analog input signal into n parallel channels, respectively, a plurality of optical delay elements providing n parallel delayed input optical sampling signals, n photodiodes converting the n parallel optical analog input signals into n respective electrical output signals, and n optical modulators modulating the input optical sampling signal or the optical analog input signal by the respective electrical output signals, and providing n successive optical samples of the optical analog input signal. A plurality of output photodiodes and eADCs convert the n successive optical samples to n successive digital samples. The optical modulator may be a photodiode interconnected Mach-Zehnder Modulator. A method of sampling the optical analog input signal is disclosed.

  14. Multispectral Resource Sampler Workshop

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The utility of the multispectral resource sampler (MRS) was examined by users in the following disciplines: agriculture, atmospheric studies, engineering, forestry, geology, hydrology/oceanography, land use, and rangelands/soils. Modifications to the sensor design were recommended and the desired types of products and number of scenes required per month were indicated. The history, design, capabilities, and limitations of the MRS are discussed as well as the multilinear spectral array technology which it uses. Designed for small area inventory, the MRS can provide increased temporal, spectral, and spatial resolution, facilitate polarization measurement and atmospheric correction, and test onboard data compression techniques. The advantages of using it along with the thematic mapper are considered.

  15. COMPARISON OF 24H AVERAGE VOC MONITORING RESULTS FOR RESIDENTIAL INDOOR AND OUTDOOR AIR USING CARBOPACK X-FILLED DIFFUSIVE SAMPLERS AND ACTIVE SAMPLING - A PILOT STUDY

    EPA Science Inventory

    Analytical results obtained by thermal desorption GC/MS for 24h diffusive sampling of 11 volatile organic compounds (VOCs) are compared with results of time-averaged active sampling at a known constant flow rate. Air samples were collected with co-located duplicate diffusive samp...

  16. Validation of parachlorobenzotrifluoride, benzotrifluoride, and monochlorotoluene on diffusive samplers.

    PubMed

    Yost, C; Harper, M

    2000-01-01

    Three solvents (OXSOL 10, monochlorotoluene or mixed isomers of 1- chloro-2-methyl benzene and 1-chloro-4-methyl benzene; OXSOL 100, parachlorobenzotrifluoride or 1-chloro-4-(trifluoromethyl) benzene; and OXSOL 2000, benzotrifluoride or trifluoromethyl benzene) produced by Occidental Chemical Corporation (Niagara Falls, NY) were considered as candidates for SKC, Inc.'s on-going diffusive sampler validation program. The 575-series diffusive sampler contains coconut-shell charcoal (575-001) or Anasorb 747 (575-002). Both samplers were used in this study. Desorption efficiency was tested at loadings equivalent to eight-hour time-weighted average (TWA) exposures to 0.01-2 times the Occidental Chemical Corporation in-house limit values (respectively: 50 ppm, 25 ppm, and 100 ppm,. All results met the National Institute for Occupational Safety and Health (NIOSH) criteria of > 75 percent, and, except for the lower loadings of parachlorobenzotrifluoride, the results were in the range of 90-110 percent. The calculated uptake rates were verified for different periods of exposure, up to eight hours, and found to be within 5 percent of the calculated for all three compounds on both samplers. A detailed comparison of the results from different time periods indicated no significant reverse diffusion effects for any combination of sampler and analyte. Samplers exposed to standard atmospheres of each compound were stored for three weeks at ambient temperatures and reanalyzed with results between 94 and 107 percent of expected. Based on full validation of samplers for the lower homologue (benzene), the bi-level theory of sample validation as endorsed by international validation protocols establishes this as a complete validation of the featured samplers for sampling vapors of these chemicals in air. PMID:10712072

  17. 40 CFR 53.59 - Aerosol transport test for Class I equivalent method samplers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... specified in 40 CFR part 50, appendix L or appendix O, as applicable. The test requirements and performance... specified for a reference method sampler in 40 CFR part 50, appendix L or appendix O, as applicable, such as... candidate samplers in which the aerosol flow path (the flow path through which sample air passes upstream...

  18. 40 CFR 53.59 - Aerosol transport test for Class I equivalent method samplers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... specified in 40 CFR part 50, appendix L or appendix O, as applicable. The test requirements and performance... specified for a reference method sampler in 40 CFR part 50, appendix L or appendix O, as applicable, such as... candidate samplers in which the aerosol flow path (the flow path through which sample air passes upstream...

  19. High speed sampler and demultiplexer

    DOEpatents

    McEwan, T.E.

    1995-12-26

    A high speed sampling demultiplexer based on a plurality of sampler banks, each bank comprising a sample transmission line for transmitting an input signal, a strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates at respective positions along the sample transmission line for sampling the input signal in response to the strobe signal. Strobe control circuitry is coupled to the plurality of banks, and supplies a sequence of bank strobe signals to the strobe transmission lines in each of the plurality of banks, and includes circuits for controlling the timing of the bank strobe signals among the banks of samplers. Input circuitry is included for supplying the input signal to be sampled to the plurality of sample transmission lines in the respective banks. The strobe control circuitry can repetitively strobe the plurality of banks of samplers such that the banks of samplers are cycled to create a long sample length. Second tier demultiplexing circuitry is coupled to each of the samplers in the plurality of banks. The second tier demultiplexing circuitry senses the sample taken by the corresponding sampler each time the bank in which the sampler is found is strobed. A plurality of such samples can be stored by the second tier demultiplexing circuitry for later processing. Repetitive sampling with the high speed transient sampler induces an effect known as ``strobe kickout``. The sample transmission lines include structures which reduce strobe kickout to acceptable levels, generally 60 dB below the signal, by absorbing the kickout pulses before the next sampling repetition. 16 figs.

  20. High speed sampler and demultiplexer

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    A high speed sampling demultiplexer based on a plurality of sampler banks, each bank comprising a sample transmission line for transmitting an input signal, a strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates at respective positions along the sample transmission line for sampling the input signal in response to the strobe signal. Strobe control circuitry is coupled to the plurality of banks, and supplies a sequence of bank strobe signals to the strobe transmission lines in each of the plurality of banks, and includes circuits for controlling the timing of the bank strobe signals among the banks of samplers. Input circuitry is included for supplying the input signal to be sampled to the plurality of sample transmission lines in the respective banks. The strobe control circuitry can repetitively strobe the plurality of banks of samplers such that the banks of samplers are cycled to create a long sample length. Second tier demultiplexing circuitry is coupled to each of the samplers in the plurality of banks. The second tier demultiplexing circuitry senses the sample taken by the corresponding sampler each time the bank in which the sampler is found is strobed. A plurality of such samples can be stored by the second tier demultiplexing circuitry for later processing. Repetitive sampling with the high speed transient sampler induces an effect known as "strobe kickout". The sample transmission lines include structures which reduce strobe kickout to acceptable levels, generally 60 dB below the signal, by absorbing the kickout pulses before the next sampling repetition.

  1. Variable depth core sampler

    SciTech Connect

    Bourgeois, P.M.; Reger, R.J.

    1994-12-31

    This invention relates to a sampling means, more particularly to a device to sample hard surfaces at varying depths. Often it is desirable to take samples of a hard surface wherein the samples are of the same diameter but of varying depths. Current practice requires that a full top-to-bottom sample of the material be taken, using a hole saw, and boring a hole from one end of the material to the other. The sample thus taken is removed from the hole saw and the middle of said sample is then subjected to further investigation. This paper describes a variable depth core sampler comprimising a circular hole saw member, having longitudinal sections that collapse to form a point and capture a sample, and a second saw member residing inside the first hole saw member to support the longitudinal sections of the first member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside the the first hole saw member.

  2. Comparison of 24 h averaged VOC monitoring results for residential indoor and outdoor air using Carbopack X-filled diffusive samplers and active sampling--a pilot study.

    PubMed

    McClenny, William A; Jacumin, Henry H; Oliver, Karen D; Daughtrey, E Hunter; Whitaker, Donald A

    2006-02-01

    Analytical results obtained by thermal desorption GC/MS for 24 h diffusive sampling of 11 volatile organic compounds (VOCs) are compared with results of time-averaged active sampling at a known constant flow rate. Air samples were collected with co-located duplicate diffusive sampling tubes and one passivated canister. A total of eight multiple-component sampling events took place at fixed positions inside and outside three private homes. Subsequently, a known amount of sample air was transferred from the canister to an adsorbent tube for analysis by thermal desorption GC/MS. Results for the 11 most prevalent compounds--Freon 11, 1,3-butadiene, benzene, toluene, tetrachloroethene, ethylbenzene, m,p-xylene, o-xylene, 4-ethyltoluene, 1,3,5-trimethylbenzene, and p-dichlorobenzene--show that the ratio of average study values (diffusive sampling to active sampling) is 0.92 with 0.70 and 1.14 extreme ratios. Absolute percent difference for duplicate samples using diffusive sampling was <10% for the four most prevalent compounds. Agreement between the two sampling approaches indicates that the prediction of approximately constant diffusive sampling rates based on previous laboratory studies is valid under the field conditions.

  3. Biomonitoring of air quality in the Cologne Conurbation using pine needles as a passive sampler - Part III: Major and trace elements

    NASA Astrophysics Data System (ADS)

    Lehndorff, E.; Schwark, L.

    2010-08-01

    We here report complementary trace element (Fe, Pb, Cd, Zn, Cr, Cu, Ni and sulfur) concentrations and ratios in pine needles collected in the urban area of Cologne, Germany. Potential element sources are discussed in conjunction with enviromagnetic and PAH data to evaluate air quality. Foliar trace element concentrations of Zn, Cr, Cu, Ni and sulfur are close to essential nutrient levels. Median concentrations of foliar Fe, Pb and Cd in Cologne are 132, 1.1, and 0.06 μg g -1, respectively. Thus these elements are enhanced over biogenic background levels and show significant accumulation with needle exposure time. Foliar sulfur concentrations vary between 868 and 2076 μg g -1 with a median value of 1409 μg g -1, except for two locations where 2370 and 2379 μg g -1 were observed. Cadmium serves as an indicator for local industrial emissions with short transport distances of only a few kilometres in Cologne City. Elevated Fe, Pb and Zn concentrations mark areas with higher traffic loads and agree with enhanced PAH burdens and magnetic susceptibility intensities of pine needles. Isopleths mapping and source differentiation of atmospheric pollutants using foliar trace elements is feasible. For temporal or spatial high-resolution studies more cost-effective environmental magnetics is recommended, which may guide in design of detailed studies aiming at identification and allocation of emission sources. Hereby, a combination of organic tracers (PAH), magnetic properties, and trace metals is considered most reliable.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. The J-PAS filter system

    NASA Astrophysics Data System (ADS)

    Marin-Franch, Antonio; Taylor, Keith; Cenarro, Javier; Cristobal-Hornillos, David; Moles, Mariano

    2015-08-01

    J-PAS (Javalambre-PAU Astrophysical Survey) is a Spanish-Brazilian collaboration to conduct a narrow-band photometric survey of 8500 square degrees of northern sky using an innovative filter system of 59 filters, 56 relatively narrow-band (FWHM=14.5 nm) filters continuously populating the spectrum between 350 to 1000nm in 10nm steps, plus 3 broad-band filters. This filter system will be able to produce photometric redshifts with a precision of 0.003(1 + z) for Luminous Red Galaxies, allowing J-PAS to measure the radial scale of the Baryonic Acoustic Oscillations. The J-PAS survey will be carried out using JPCam, a 14-CCD mosaic camera using the new e2v 9k-by-9k, 10μm pixel, CCDs mounted on the JST/T250, a dedicated 2.55m wide-field telescope at the Observatorio Astrofísico de Javalambre (OAJ) near Teruel, Spain. The filters will operate in a fast (f/3.6) converging beam. The requirements for average transmissions greater than 85% in the passband, <10-5 blocking from 250 to 1050nm, steep bandpass edges and high image quality impose significant challenges for the production of the J-PAS filters that have demanded the development of new design solutions. This talk presents the J-PAS filter system and describes the most challenging requirements and adopted design strategies. Measurements and tests of the first manufactured filters are also presented.

  6. Setting the PAS, the role of circadian PAS domain proteins during environmental adaptation in plants

    PubMed Central

    Vogt, Julia H. M.; Schippers, Jos H. M.

    2015-01-01

    The per-ARNT-sim (PAS) domain represents an ancient protein module that can be found across all kingdoms of life. The domain functions as a sensing unit for a diverse array of signals, including molecular oxygen, small metabolites, and light. In plants, several PAS domain-containing proteins form an integral part of the circadian clock and regulate responses to environmental change. Moreover, these proteins function in pathways that control development and plant stress adaptation responses. Here, we discuss the role of PAS domain-containing proteins in anticipation, and adaptation to environmental changes in plants. PMID:26217364

  7. Mapping of tritium emissions using absorption vapour samplers.

    PubMed

    Vodila, Gergely; Molnár, Mihály; Veres, Mihály; Svingor, Eva; Futó, István; Barnabás, István; Kapitány, Sándor

    2009-02-01

    Püspökszilágy Radioactive Waste Treatment and Disposal Facility (RWTDF) is a typical near-surface engineered repository designated to store low- and intermediate-level wastes from various institutes, research facilities and hospitals in Hungary. Two automatic combined (14)C-tritium sampling units installed at the facility sample the air 2 m above surface. The one installed near the vaults detects tritium (T) activities two orders of magnitude higher than the far reference sampling unit. To localize the T emissions, 19 small absorption vapour samplers filled with silica gel were settled onto the ground surface. After the saturation of the silica gel, the water was recovered and its T concentration was measured with a low-background liquid scintillation counter. The absorption vapour samplers are cheap, simple and easy-to-use. We present the samplers and the T distribution map constructed from the data, which helps to localize the T emission. PMID:19027205

  8. Quartz measurement in coal dust with high-flow rate samplers: laboratory study.

    PubMed

    Lee, Taekhee; Lee, Eun Gyung; Kim, Seung Won; Chisholm, William P; Kashon, Michael; Harper, Martin

    2012-05-01

    A laboratory study was performed to measure quartz in coal dust using high-flow rate samplers (CIP10-R, GK2.69 cyclone, and FSP10 cyclone) and low-flow rate samplers [10-mm nylon and Higgins-Dewell type (BGI4L) cyclones] and to determine whether an increased mass collection from high-flow rate samplers would affect the subsequent quartz measurement by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analytical procedures. Two different sizes of coal dusts, mass median aerodynamic diameter 4.48 μm (Coal Dust A) and 2.33 μm (Coal Dust B), were aerosolized in a calm air chamber. The mass of coal dust collected by the samplers was measured gravimetrically, while the mass of quartz collected by the samplers was determined by FTIR (NIOSH Manual of Analytical Method 7603) and XRD (NIOSH Manual of Analytical Method 7500) after one of two different indirect preparations. Comparisons between high-flow rate samplers and low-flow rate samplers were made by calculating mass concentration ratios of coal dusts, net mass ratios of coal dusts, and quartz net mass. Mass concentrations of coal dust from the FSP10 cyclone were significantly higher than those from other samplers and mass concentrations of coal dust from 10-mm nylon cyclone were significantly lower than those from other samplers, while the CIP10-R, GK2.69, and BGI4L samplers did not show significant difference in the comparison of mass concentration of coal dusts. The BGI4L cyclone showed larger mass concentration of ∼9% compared to the 10-mm nylon cyclone. All cyclones provided dust mass concentrations that can be used in complying with the International Standard Organization standard for the determination of respirable dust concentration. The amount of coal dust collected from the high-flow rate samplers was found to be higher with a factor of 2-8 compared to the low-flow rate samplers but not in direct proportion of increased flow rates. The high-flow rate samplers collected more quartz compared to

  9. A High Volume Stack Sampler

    NASA Technical Reports Server (NTRS)

    Boubel, Richard W.

    1971-01-01

    The stack sampler described in this paper has been developed to overcome the difficulties of particulate sampling with presently available equipment. Its use on emissions from hog fuel fired boilers, back-fired incinerators, wigwam burners, asphalt plants, and seed cleaning cyclones is reported. The results indicate that the sampler is rapid and reliable in its use. It is relatively simple and inexpensive to operate. For most sources it should be considered over the more complicated and expensive sampling trains being used and specified.

  10. Conservation and specialization in PAS domain dynamics.

    PubMed

    Pandini, A; Bonati, L

    2005-03-01

    The PAS (Per-ARNT-Sim) superfamily is presented as a well-suited study case to demonstrate how comparison of functional motions among distant homologous proteins with conserved fold characteristics may give insight into their functional specialization. Based on the importance of structural flexibility of the receptive structures in anticipating the signal-induced conformational changes of these sensory systems, the dynamics of these structures were analysed. Molecular dynamics was proved to be an effective method to obtain a reliable picture of the dynamics of the crystal structures of HERG, phy3, PYP and FixL, provided that an extensive conformational space sampling is performed. Other reliable sources of dynamic information were the ensembles of NMR structures of hPASK, HIF-2alpha and PYP. Essential dynamics analysis was successfully employed to extract the relevant information from the sampled conformational spaces. Comparison of motion patterns in the essential subspaces, based on the structural alignment, allowed identification of the specialized region in each domain. This appears to be evolved in the superfamily by following a specific trend, that also suggests the presence of a limited number of general solutions adopted by the PAS domains to sense external signals. These findings may give insight into unknown mechanisms of PAS domains and guide further experimental studies. PMID:15820977

  11. A comparison of X-ray fluorescence and wet chemical analysis for lead on air filters from different personal samplers used in a secondary lead smelter/solder manufacturer.

    PubMed

    Harper, Martin; Pacolay, Bruce

    2006-01-01

    Portable X-ray fluorescence (XRF) technology may provide faster turn-around without compromising accuracy when assessing personal exposures to metals such as lead, but it has only been tested in limited field environments. This study is part of a series, where various types of sampler are used to collect airborne lead in different environments for presentation to a portable XRF analyzer. In this case personal samples were taken at a manufacturer of solder alloys consisting mainly of lead and tin, using the closed-face 37 mm cassette (CFC), 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. Following XRF analysis the samples were extracted with acid and analyzed by inductively coupled plasma optical emission spectroscopy (ICP). The internal surfaces of CFC's and 25 mm open-face cassettes were also wiped, and the wipes analyzed for lead to assess wall-losses in these two samplers. Analysis of all elements present is useful to ascertain contributions to matrix interference effects. In addition to lead, other metals such as tin, copper, iron, silver, cadmium and antimony were also detected in some or all of the samples by ICP analysis, but only copper and iron could be determined using the XRF analyzer under test. After the removal of a few outliers, all five samplers gave good correlations (r(2) > 0.9) between the two analytical methods over the entire range of found lead mass, which encompassed both the action level and the permissible exposure limit enforced in the USA by the Occupational Safety and Health Administration (OSHA). Linear regression on the results from most samplers gave almost 1 ratio 1 correlations without additional correction, indicating an absence of matrix effects, particularly from tin, which was the most common element after lead. The average of three XRF readings across filters

  12. An automatic, refrigerated, sequential precipitation sampler

    NASA Astrophysics Data System (ADS)

    Coscio, M. R.; Pratt, G. C.; Krupa, S. V.

    The design and characteristics of an automated, refrigerated, sequential precipitation sampler are described. This sampler can collect rainfall on an event basis or as sequential segments within a rain event. Samples are sealed upon collection to prevent gas exchange and are refrigerated in situ at 4 ± 2° C. This sampler is commercially available.

  13. A Sampler of Ethnic Crafts.

    ERIC Educational Resources Information Center

    Donley, Susan K.; And Others

    This curriculum guide provides a sampler of the wide variety of expression practiced by cultural groups all over the world. The guide was developed to help fill the need for multicultural art resources that are respectful of both modern art education philosophy and of authentic, sensitive representation of other cultures. The types of materials…

  14. A Sampler of Mathematics Assessment.

    ERIC Educational Resources Information Center

    Pandey, Tej; Smith, Theodore R., Ed.

    The California Assessment Program (CAP) administers tests to all public school students at certain grade levels, compiles the results, and provides information that allows educators to judge the effectiveness of their programs and make improvements. This sampler describes the types of assessment that CAP proposes to respond to the needed changes…

  15. Evolution of PAS domains and PAS-containing genes in eukaryotes.

    PubMed

    Mei, Qiming; Dvornyk, Volodymyr

    2014-08-01

    The PAS domains are signal modules, which are widely distributed in proteins across all kingdoms of life. They are common in photoreceptors and transcriptional regulators of eukaryotic circadian clocks q(bHLH-PAS proteins and PER in animals; PHY and ZTL in plants; and WC-1, 2, and VVD in fungi) and possess mainly protein-protein interaction and light-sensing functions. We conducted several evolutionary analyses of the PAS superfamily. Although the whole superfamily evolved primarily under strong purifying selection (average ω ranges from 0.0030 to 0.1164), some lineages apparently experienced strong episodic positive selection at some periods of the evolution. Although the PAS domains from different proteins vary in sequence and length, but they maintain a fairly conserved 3D structure, which is determined by only eight residues. The WC-1 and WC- 2, bHLH-PAS, and P er genes probably originated in the Neoproterozoic Era (1000-542 Mya), plant P hy and ZTL evolved in the Paleozoic (541-252 Mya), which might be a result of adaptation to the major climate and global light regime changes having occurred in those eras.

  16. Soil separator and sampler and method of sampling

    DOEpatents

    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.

  17. Ultra-wideband directional sampler

    DOEpatents

    McEwan, T.E.

    1996-05-14

    The Ultra-Wideband (UWB) Directional Sampler is a four port device that combines the function of a directional coupler with a high speed sampler. Two of the four ports operate at a high sub-nanosecond speed, in ``real time``, and the other two ports operate at a slow millisecond-speed, in ``equivalent time``. A signal flowing inbound to either of the high speed ports is sampled and coupled, in equivalent time, to the adjacent equivalent time port while being isolated from the opposite equivalent time port. A primary application is for a time domain reflectometry (TDR) situation where the reflected pulse returns while the outbound pulse is still being transmitted, such as when the reflecting discontinuity is very close to the TDR apparatus. 3 figs.

  18. Ultra-wideband directional sampler

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    The Ultra-Wideband (UWB) Directional Sampler is a four port device that combines the function of a directional coupler with a high speed sampler. Two of the four ports operate at a high sub-nanosecond speed, in "real time", and the other two ports operate at a slow millisecond-speed, in "equivalent time". A signal flowing inbound to either of the high speed ports is sampled and coupled, in equivalent time, to the adjacent equivalent time port while being isolated from the opposite equivalent time port. A primary application is for a time domain reflectometry (TDR) situation where the reflected pulse returns while the outbound pulse is still being transmitted, such as when the reflecting discontinuity is very close to the TDR apparatus.

  19. Conditional Sampling of Ammonia at Livestock Operations Using Robotically Controlled Diffusive Samplers

    NASA Astrophysics Data System (ADS)

    Ham, J. M.; Williams, C.; Stratton, J. J.; Borch, T.

    2011-12-01

    Diffusive/passive samplers can be used to measure the spatial variations in ammonia and other trace gases near livestock operations, but results are often confounded by changing weather conditions during extended deployment periods (e.g., 1 to 2 weeks). A new type of conditional sampler was developed that only exposes the passive samplers when a user-defined set of wind and weather conditions are met. The samplers were housed in air-tight tubes that could be opened and closed with a motorized actuator controlled by datalogger. Samplers were deployed on portable tripods and linked via a wireless network. Multiple tripods, equipped with Radiello diffusive NH3 samplers, were deployed near cattle feedlots and dairies and programmed to only expose the passive samplers when the upwind source area represented a specific zone of the operation. A base-station with an anemometer, wind vane, thermometer, and humidity sensor controlled sampling at all tripods. This new methodology allows improved detection of spatial variation in emissions near livestock operations and provides more accurate measurements of downwind gradients. Data could be used in inverse models to approximate site specific emissions factors for ammonia.

  20. Field tests of diffusion samplers for inorganic constituents in wells and at a ground-water discharge zone

    USGS Publications Warehouse

    Vroblesky, Don A.; Petkewich, Matthew D.; Campbell, Ted R.

    2002-01-01

    Field tests were performed on two types of diffusion samplers to collect representative samples of inorganic constituents from ground water in wells and at an arsenic-contaminated ground-water-discharge zone beneath a stream. Nylon-screen samplers and dialysis samplers were tested for the collection of arsenic, calcium, chloride, iron, manganese, sulfate, and dissolved oxygen. The investigations were conducted at the Naval Industrial Reserve Ordnance Plant (NIROP), Fridley, Minnesota, and at the Naval Air Station Fort Worth Joint Reserve Base (NAS Fort Worth JRB), Texas. Data indicate that, in general, nylon-screen and dialysis diffusion samplers are capable of obtaining concentrations of inorganic solutes in ground water that correspond to concentrations obtained by low-flow sampling. Diffusion samplers offer a potentially time-saving approach to well sampling. Particular care must be taken, however, when sampling for iron and other metals, because of the potential for iron precipitation by oxygenation and when dealing with chemically stratified sampling intervals. Simple nylon-screen jar samplers buried beneath creekbed sediment appear to be effective tools for locating discharge zones of arsenic contaminated ground water. Although the LDPE samplers have proven to be inexpensive and simple to use in wells, they are limited by their inability to provide a representative sample of ionic solutes. The success of nylon-screen samplers in sediment studies suggests that these simple samplers may be useful for collecting water samples for inorganic constituents in wells. Results using dialysis bags deployed in wells suggest that these types of samplers have the potential to provide a representative sample of both VOCs and ionic solutes from ground water (Kaplan and others, 1991; Theodore A. Ehlke, U.S. Geological Survey, written commun., 2001). The purpose of this report is to provide results of field tests investigating the potential to use diffusion samplers to collect

  1. 7 CFR 29.20 - Sampler.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Sampler. 29.20 Section 29.20 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Regulations Definitions § 29.20 Sampler. Person employed, licensed, or authorized by the...

  2. Quantitative organic vapor-particle sampler

    DOEpatents

    Gundel, Lara; Daisey, Joan M.; Stevens, Robert K.

    1998-01-01

    A quantitative organic vapor-particle sampler for sampling semi-volatile organic gases and particulate components. A semi-volatile organic reversible gas sorbent macroreticular resin agglomerates of randomly packed microspheres with the continuous porous structure of particles ranging in size between 0.05-10 .mu.m for use in an integrated diffusion vapor-particle sampler.

  3. Fluidized Bed Asbestos Sampler Design and Testing

    SciTech Connect

    Karen E. Wright; Barry H. O'Brien

    2007-12-01

    A large number of samples are required to characterize a site contaminated with asbestos from previous mine or other industrial operations. Current methods, such as EPA Region 10’s glovebox method, or the Berman Elutriator method are time consuming and costly primarily because the equipment is difficult to decontaminate between samples. EPA desires a shorter and less costly method for characterizing soil samples for asbestos. The objective of this was to design and test a qualitative asbestos sampler that operates as a fluidized bed. The proposed sampler employs a conical spouted bed to vigorously mix the soil and separate fine particulate including asbestos fibers on filters. The filters are then analyzed using transmission electron microscopy for presence of asbestos. During initial testing of a glass prototype using ASTM 20/30 sand and clay fines as asbestos surrogates, fine particulate adhered to the sides of the glass vessel and the tubing to the collection filter – presumably due to static charge on the fine particulate. This limited the fines recovery to ~5% of the amount added to the sand surrogate. A second prototype was constructed of stainless steel, which improved fines recovery to about 10%. Fines recovery was increased to 15% by either humidifying the inlet air or introducing a voltage probe in the air space above the sample. Since this was not a substantial improvement, testing using the steel prototype proceeded without using these techniques. Final testing of the second prototype using asbestos suggests that the fluidized bed is considerably more sensitive than the Berman elutriator method. Using a sand/tremolite mixture with 0.005% tremolite, the Berman elutriator did not segregate any asbestos structures while the fluidized bed segregated an average of 11.7. The fluidized bed was also able to segregate structures in samples containing asbestos at a 0.0001% concentration, while the Berman elutriator method did not detect any fibers at this

  4. Prevocational Assessment Screen (P.A.S.) Evaluator's Manual.

    ERIC Educational Resources Information Center

    Rosinek, Michele

    The Prevocational Assessment Screen (PAS) is designed to provide instructors or evaluators with a quick (50 minutes to score and administer) and simple (requiring no training to administer) method of screening mildly handicapped and disadvantaged youth between 14 and 21 years of age for job training and placement. PAS contains eight samples which…

  5. Permeation absorption sampler with multiple detection

    DOEpatents

    Zaromb, Solomon

    1990-01-01

    A system for detecting analytes in air or aqueous systems includes a permeation absorption preconcentrator sampler for the analytes and analyte detectors. The preconcentrator has an inner fluid-permeable container into which a charge of analyte-sorbing liquid is intermittently injected, and a fluid-impermeable outer container. The sample is passed through the outer container and around the inner container for trapping and preconcentrating the analyte in the sorbing liquid. The analyte can be detected photometrically by injecting with the sorbing material a reagent which reacts with the analyte to produce a characteristic color or fluorescence which is detected by illuminating the contents of the inner container with a light source and measuring the absorbed or emitted light, or by producing a characteristic chemiluminescence which can be detected by a suitable light sensor. The analyte can also be detected amperometrically. Multiple inner containers may be provided into which a plurality of sorbing liquids are respectively introduced for simultaneously detecting different analytes. Baffles may be provided in the outer container. A calibration technique is disclosed.

  6. Guidance on the use of passive-vapor-diffusion samplers to detect volatile organic compounds in ground-water-discharge areas, and example applications in New England

    USGS Publications Warehouse

    Church, Peter E.; Vroblesky, Don A.; Lyford, Forest P.

    2002-01-01

    Polyethylene-membrane passive-vapor-diffusion samplers, or PVD samplers, have been shown to be an effective and economical reconnaissance tool for detecting and identifying volatile organic compounds (VOCs) in bottom sediments of surface-water bodies in areas of ground-water discharge. The PVD samplers consist of an empty glass vial enclosed in two layers of polyethylene membrane tubing. When samplers are placed in contaminated sediments, the air in the vial equilibrates with VOCs in pore water. Analysis of the vapor indicates the presence or absence of VOCs and the likely magnitude of concentrations in pore water.

  7. Probabilistic Algorithm for Sampler Siting (PASS)

    2007-05-29

    PASS (Probabilistic Approach to Sampler Siting) optimizes the placement of samplers in buildings. The program exhaustively checks every sampler-network that can be formed, evaluating against user-supplied simulations of the possible release scenarios. The program identifies the networks that maximize the probablity of detecting a release from among the suite of user-supllied scenarios. The user may specify how many networks to report, in order to provide a number of choices in cases where many networks havemore » very similar behavior.« less

  8. Passive sampler for measurements of atmospheric nitric acid vapor (HNO3) concentrations.

    PubMed

    Bytnerowicz, A; Padgett, P E; Arbaugh, M J; Parker, D R; Jones, D P

    2001-12-01

    Nitric acid (HNO3) vapor is an important nitrogenous air pollutant responsible for increasing saturation of forests with nitrogen and direct injury to plants. The USDA Forest Service and University of California researchers have developed a simple and inexpensive passive sampler for monitoring air concentrations of HNO3. Nitric acid is selectively absorbed on 47-mm Nylasorb nylon filters with no interference from particulate NO3-. Concentrations determined with the passive samplers closely corresponded with those measured with the co-located honeycomb annular denuder systems. The PVC protective caps of standardized dimensions protect nylon filters from rain and wind and allow for reliable measurements of ambient HNO3 concentrations. The described samplers have been successfully used in Sequoia National Park, the San Bernardino Mountains, and on Mammoth Mountain in California.

  9. NAPL Characterization Using the Ribbon NAPL Sampler

    SciTech Connect

    Riha, B.D.

    1999-12-01

    The Ribbon NAPL Sampler (RNS) is a direct sampling device that can provide detailed depth discrete mapping of Non Aqueous Phase Liquids (NAPLs - liquid solvents and/or petroleum products) in a borehole.

  10. A plane-type soil sampler

    USGS Publications Warehouse

    Frey, Paul J.

    1963-01-01

    While studying the effects of pesticides on fish and their environment for the Bureau of Sport Fisheries and Wildlife, I have developed a soil sampler that will collect a thin uniform layer of sediment from pond and stream bottoms. As it is becoming increasingly important to analyze the residual deposits of pesticides in this shallow layer of soil in aquatic environments, it seems useful to describe the apparatus and compare it with other samplers.

  11. Evaluation of a novel personal nanoparticle sampler.

    PubMed

    Zhou, Yue; Irshad, Hammad; Tsai, Chuen-Jinn; Hung, Shao-Ming; Cheng, Yung-Sung

    2014-02-01

    This work investigated the performance in terms of collection efficiency and aspiration efficiency of a personal sampler capable of collecting ultrafine particles (nanoparticles) in the occupational environment. This sampler consists of a cyclone for respirable particle classification, micro-orifice impactor stages with an acceleration nozzle to achieve nanoparticle classification and a backup filter to collect nanoparticles. Collection efficiencies of the cyclone and impactor stages were determined using monodisperse polystyrene latex and silver particles, respectively. Calibration of the cyclone and impactor stages showed 50% cut-off diameters of 3.95 μm and 94.7 nm meeting the design requirements. Aspiration efficiencies of the sampler were tested in a wind tunnel with wind speeds of 0.5, 1.0, and 1.5 m s(-1). The test samplers were mounted on a full size mannequin with three orientations toward the wind direction (0°, 90°, and 180°). Monodisperse oleic acid aerosols tagged with sodium fluorescein in the size range of 2 to 10 μm were used in the test. For particles smaller than 2 μm, the fluorescent polystyrene latex particles were generated by using nebulizers. For comparison of the aspiration efficiency, a NIOSH two-stage personal bioaerosol sampler was also tested. Results showed that the orientation-averaged aspiration efficiency for both samplers was close to the inhalable fraction curve. However, the direction of wind strongly affected the aspiration efficiency. The results also showed that the aspiration efficiency was not affected by the ratio of free-stream velocity to the velocity through the sampler orifice. Our evaluation showed that the current design of the personal sampler met the designed criteria for collecting nanoparticles ≤100 nm in occupational environments.

  12. INSTRUCTIONS FOR OPERATING LBL FORMALDEHYDE SAMPLER

    SciTech Connect

    Fanning, L.Z.; Allen, J.R.; Miksch, R.R.

    1981-09-01

    The LBL formaldehyde sampler consists of two parts: 1) a pump box and 2) a small refrigerator housing sampling bubblers. The pump box contains two pumps, a timer, a flow controller, an electrical cord, and a ten-foot piece of tubing to connect the refrigerator to the pump box. The small refrigerator contains four columns of bubbler sampling trains attached to a metal plate. Two sampling trains each are plumbed in parallel to two sampling ports on the back of the refrigerator. The two sampling lines supplied are to be attached to these ports to allow two locations to be sampled at once (usually one indoor and one outdoor). The refrigerator also contains a rack for holding bubbler tubes. In the sampling process, air is drawn through a sampling line attached to the fitting at the back of the refrigerator and into a prlmary bubbler containing a trapping solution. This trapping solution can be distilled water or an aqueous solution of some compound that reacts with formaldehyde. From this bubbler the air goes through a second bubbler containing the same trapping solution as the first bubbler. (To maintain sample integrity, all parts that the air sample contacts are made of Teflon, polypropylene, and stainless steel.) The air then goes into the third bubbler, which contains no liquid. This bubbler contains a hypodermic needle that serves as a flow-control orifice. The hypodermic needle, in conjunction with the flow controller in the pump box, ensures a constant a flow rate. The refrigerator contains four columns of these sets of three bubblers. After samples have been collected, the bubbler bottoms are detached and the contents of the first and second bubblers in each column are poured together, capped, and labeled. The use of a refrigerated primary and secondary bubbler whose contents are combined at the end of a sampling period ensures 95% collection efficiency. After the bubbler tubes are capped and labeled, they are stored either in the rack supplied in the

  13. Feasibility of classification of clay minerals by using PAS

    NASA Astrophysics Data System (ADS)

    Honda, Y.; Yoshida, Y.; Akiyama, Y.; Nishijima, S.

    2015-06-01

    After the nuclear power plant disaster, the evaluation of radioactive Cs kept in soil, especially in clay minerals and the elucidation of its movement are urgent subjects to promote decontamination. It is known that the extractable level of Cs depends on the sort of clay minerals. We tried to find the characteristics of clay minerals belonging to phillosilicate group using positron annihilation spectroscopy (PAS) and the relationship between the results of PAS and the amounts of substantially extracted Cs from the clay minerals. The results showed that each clay mineral was found to be distinguishable from other clay minerals by PAS and the extraction rate of Cs was different among those clay minerals, however the direct correlation between the results of PAS and the extraction rates of Cs was not found.

  14. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  15. EVALUATION OF IN SITU COSOLVENT FLUSHING DYNAMICS USING A NETWORK OF SPATIALLY DISTRIBUTED MULTILEVEL SAMPLERS

    EPA Science Inventory

    A network of multilevel samplers was used to evaluate the spatial patterns in containment extraction during an in situ cosolvent flushing field test. The study was conducted in an isolation test cell installed in a fuel contaminated site at Hill Air Force Base, Utah. Partitioni...

  16. Measurement of gaseous PAHs with an innovative passive sampler in community exposure studies

    EPA Science Inventory

    A sensitive, simple, and cost-effective passive sampling methodology was developed to quantify gaseous polycyclic aromatic hydrocarbons (PAHs) in personal, indoor and outdoor air. A Fan-Lioy passive PAH sampler (FL-PPS) is constructed from four 80 sections of 1 cm long SPB-5 GC c...

  17. Spatial analysis of volatile organic compounds in South Philadelphia using passive samplers

    EPA Science Inventory

    Select volatile organic compounds (VOCs) were measured in the vicinity of a petroleum refinery and related operations in South Philadelphia, Pennsylvania, USA, using passive air sampling and laboratory analysis methods. Two-week, time-integrated samplers were deployed at 17 sites...

  18. Passive flux sampler for measurement of formaldehyde emission rates

    NASA Astrophysics Data System (ADS)

    Shinohara, Naohide; Fujii, Minoru; Yamasaki, Akihiro; Yanagisawa, Yukio

    A new passive flux sampler (PFS) was developed to measure emission rates of formaldehyde and to determine emission sources in indoor environments. The sampler consisted of a glass Petri dish containing a 2,4-dinitrophenyl hydrazine (DNPH)-impregnated sheet. At the start of sampling, the PFS was placed with the open face of the dish on each of the indoor materials under investigation, such as flooring, walls, doors, closets, desks, beds, etc. Formaldehyde emitted from a source material diffused through the inside of the PFS and was adsorbed onto the DNPH sheet. The formaldehyde emission rates could be determined from the quantities adsorbed. The lower determination limits were 9.2 and 2.3 μg m -2 h -1 for 2- and 8-h sampling periods. The recovery rate and the precision of the PFS were 82.9% and 8.26%, respectively. The emission rates measured by PFS were in good agreement with the emission rates measured by the chamber method ( R2=0.963). This shows that it is possible to take measurements of the formaldehyde emission rates from sources in a room and to compare them. In addition, the sampler can be used to elucidate the emission characteristics of a source by carrying out emission measurements with different air-layer thicknesses inside the PFS and at different temperatures. The dependency of the emission rate on the thickness of the air layer inside the PFS indicated whether the internal mass transfer inside the source material or the diffusion in the gas-phase boundary layer controlled the formaldehyde emission rate from a material. In addition, as a pilot study, the formaldehyde emission rates were measured, and the largest emission source of formaldehyde could be identified from among several suspected materials in a model house by using the PFS.

  19. Wood Dust Sampling: Field Evaluation of Personal Samplers When Large Particles Are Present

    PubMed Central

    Lee, Taekhee; Harper, Martin; Slaven, James E.; Lee, Kiyoung; Rando, Roy J.; Maples, Elizabeth H.

    2011-01-01

    Recent recommendations for wood dust sampling include sampling according to the inhalable convention of International Organization for Standardization (ISO) 7708 (1995) Air quality—particle size fraction definitions for health-related sampling. However, a specific sampling device is not mandated, and while several samplers have laboratory performance approaching theoretical for an ‘inhalable’ sampler, the best choice of sampler for wood dust is not clear. A side-by-side field study was considered the most practical test of samplers as laboratory performance tests consider overall performance based on a wider range of particle sizes than are commonly encountered in the wood products industry. Seven companies in the wood products industry of the Southeast USA (MS, KY, AL, and WV) participated in this study. The products included hardwood flooring, engineered hardwood flooring, door skins, shutter blinds, kitchen cabinets, plywood, and veneer. The samplers selected were 37-mm closed-face cassette with ACCU-CAP™, Button, CIP10-I, GSP, and Institute of Occupational Medicine. Approximately 30 of each possible pairwise combination of samplers were collected as personal sample sets. Paired samplers of the same type were used to calculate environmental variance that was then used to determine the number of pairs of samples necessary to detect any difference at a specified level of confidence. Total valid sample number was 888 (444 valid pairs). The mass concentration of wood dust ranged from 0.02 to 195 mg m−3. Geometric mean (geometric standard deviation) and arithmetic mean (standard deviation) of wood dust were 0.98 mg m−3 (3.06) and 2.12 mg m−3 (7.74), respectively. One percent of the samples exceeded 15 mg m−3, 6% exceeded 5 mg m−3, and 48% exceeded 1 mg m−3. The number of collected pairs is generally appropriate to detect a 35% difference when outliers (negative mass loadings) are removed. Statistical evaluation of the nonsimilar sampler pair

  20. Statistical analysis of the DWPF prototypic sampler

    SciTech Connect

    Postles, R.L.; Reeve, C.P.; Jenkins, W.J.; Bickford, D.F.

    1991-12-31

    The DWPF process will be controlled using assay measurements on samples of feed slurry. These slurries are radioactive, and thus will be sampled remotely. A Hydraguard{trademark} pump-driven sampler system will be used as the remote sampling device. A prototype Hydraguard{trademark} sampler has been studied in a full-scale mock-up of a DWPF process vessel. Two issues were of dominant interest: (1) what accuracy and precision can be provided by such a pump-driven sampler in the face of the slurry rheology; and, if the Hydraguard{trademark} sample accurately represents the slurry in its local area, (2) is the slurry homogeneous enough throughout for it to represent the entire vessel? To determine Hydraguard{trademark} Accuracy, a Grab Sampler of simpler mechanism was used as reference. This (Low) Grab Sampler was located as near to the intake port of the Hydraguard{trademark} as could be arranged. To determine Homogeneity, a second (High) Grab Sampler was located above the first. The data necessary to these determinations comes from the measurement system, so its important variables also affect the results. Thus, the design of the test involved not just Sampling variables, but also some of the Measurement variables as well. However, the main concern was the Sampler and not the Measurement System, so the test design included only such measurement variables as could not be circumvented (Vials, Dissolution Method, and Aliquoting). The test was executed by, or under the direct oversight of, expert technologists. It thus did not explore the many important particulars of ``routine`` plant operations (such as Remote Sample Preparation or Laboratory Shift Operation).

  1. Statistical analysis of the DWPF prototypic sampler

    SciTech Connect

    Postles, R.L.; Reeve, C.P.; Jenkins, W.J.; Bickford, D.F.

    1991-01-01

    The DWPF process will be controlled using assay measurements on samples of feed slurry. These slurries are radioactive, and thus will be sampled remotely. A Hydraguard{trademark} pump-driven sampler system will be used as the remote sampling device. A prototype Hydraguard{trademark} sampler has been studied in a full-scale mock-up of a DWPF process vessel. Two issues were of dominant interest: (1) what accuracy and precision can be provided by such a pump-driven sampler in the face of the slurry rheology; and, if the Hydraguard{trademark} sample accurately represents the slurry in its local area, (2) is the slurry homogeneous enough throughout for it to represent the entire vessel To determine Hydraguard{trademark} Accuracy, a Grab Sampler of simpler mechanism was used as reference. This (Low) Grab Sampler was located as near to the intake port of the Hydraguard{trademark} as could be arranged. To determine Homogeneity, a second (High) Grab Sampler was located above the first. The data necessary to these determinations comes from the measurement system, so its important variables also affect the results. Thus, the design of the test involved not just Sampling variables, but also some of the Measurement variables as well. However, the main concern was the Sampler and not the Measurement System, so the test design included only such measurement variables as could not be circumvented (Vials, Dissolution Method, and Aliquoting). The test was executed by, or under the direct oversight of, expert technologists. It thus did not explore the many important particulars of routine'' plant operations (such as Remote Sample Preparation or Laboratory Shift Operation).

  2. Research highlights: natural passive samplers--plants as biomonitors.

    PubMed

    Lin, Vivian S

    2015-06-01

    In the past decade, interest in boosting the collection of data on environmental pollutants while reducing costs has spurred intensive research into passive samplers, instruments that monitor the environment through the free flow of chemical species. These devices, although relatively inexpensive compared to active sampling technologies, are often tailored for collection of specific contaminants or monitoring of a single phase, typically water or air. Plants as versatile, natural passive samplers have gained increased attention in recent years due to their ability to absorb a diverse range of chemicals from the air, water, and soil. Trees, lichens, and other flora have evolved exquisite biological features to facilitate uptake of nutrients and water from the ground and conduct gas exchange on an extraordinary scale, making them excellent monitors of their surroundings. Sampling established plant specimens in a region also provides both historical and spatial data on environmental contaminants at relatively low cost in a non-invasive manner. This Highlight presents several recent publications that demonstrate how plant biomonitoring can be used to map the distribution of a variety of pollutants and identify their sources. PMID:25980391

  3. Monitoring of urban particulate using an electret-based passive sampler

    SciTech Connect

    Thorpe, A.; Hemingway, M.A.; Brown, R.C.

    1999-11-01

    Site sampling trials have been carried out in the urban environment in order to assess the usefulness of a passive sampling device, originally developed for personal monitoring of airborne dust levels in industry. The sampling element is a small disc of elect material (polymer carrying a permanent electric charge) within a metal frame weighing approximately 15 g. The sampler is designed to capture particles by electrostatic attraction, in which case the capture rate depends on their electrical mobility but is independent of the rate at which air flows past the device. Passive samplers, along with miniaturized cascade impactors, have been exposed to urban particulate for periods of up to 28 days in locations with significant different levels of airborne pollution. The cascade impactor data enabled good estimates to be made of PM{sub 10} and PMN{sub 2.5} levels, and data from the passive sampler correlated with the total dust sampled by the impactor and with both the size fractions, that with the PM{sub 10} being better. Too few data have yet been obtained for its accuracy to be established, but it is unlikely that it will approach that of pumped samplers. It has been shown to be potentially useful for multiple, simultaneous site sampling and for monitoring personal environmental exposure situations in which dispensing with a power source is particularly useful. Being small, the sampler is easy to hide or camouflage, and because it is cheap, its loss or damage is not a serious matter.

  4. New approach to calibrating bed load samplers

    USGS Publications Warehouse

    Hubbell, D.W.; Stevens, H.H.; Skinner, J.V.; Beverage, J.P.

    1985-01-01

    Cyclic variations in bed load discharge at a point, which are an inherent part of the process of bed load movement, complicate calibration of bed load samplers and preclude the use of average rates to define sampling efficiencies. Calibration curves, rather than efficiencies, are derived by two independent methods using data collected with prototype versions of the Helley‐Smith sampler in a large calibration facility capable of continuously measuring transport rates across a 9 ft (2.7 m) width. Results from both methods agree. Composite calibration curves, based on matching probability distribution functions of samples and measured rates from different hydraulic conditions (runs), are obtained for six different versions of the sampler. Sampled rates corrected by the calibration curves agree with measured rates for individual runs.

  5. Wind tunnel and field calibration of six aeolian dust samplers

    NASA Astrophysics Data System (ADS)

    Goossens, Dirk; Offer, Zvi Y.

    The efficiency of six aeolian dust samplers was tested via wind tunnel experiments and field measurements. In the wind tunnel, four samplers designed to measure the horizontal dust flux and one sampler designed to measure the vertical dust flux (in the downward direction, i.e., deposition) were calibrated against an isokinetic reference sampler. The horizontal dust flux samplers were: the big spring number eight sampler (BSNE), the modified Wilson and Cooke sampler (MWAC), the suspended sediment trap (SUSTRA), and the wedge dust flux gauge (WDFG). Vertical deposition flux was measured using a marble dust collector (MDCO). A modified Sartorius SM 16711 dust sampler with adjustable flow rate (SARTORIUS) was used as isokinetic reference sampler. In the field experiments, the WDFG was replaced by a Sierra ultra high volume dust sampler (SIERRA). Wind tunnel calibrations were carried out at five wind velocities ranging from 1 to 5 m s -1. Field calibrations were conducted during seven periods of two weeks each. The most efficient samplers are the MWAC and the SIERRA, followed by the BSNE and the SUSTRA. The WDFG is more effective than the BSNE at velocities below 3 m s -1, but its efficiency drops quickly at higher wind speeds. The most recommendable sampler for field measurements is the BSNE, because its efficiency varies only very slightly with wind speed. In the absence of horizontal flux samplers, the MDCO collector can be used as an alternative to assess horizontal dust flux and airborne dust concentration provided the appropriate calibrations are made.

  6. [Development of the Parenting in Adolescence Scale (PAS)].

    PubMed

    Utsumi, Shoka

    2013-08-01

    The present study developed the Parenting in Adolescence Scale (PAS) based on the three-factor model of parenting by Schaefer (1965), and examined its psychometric properties. Adolescents (n = 103 junior high, 273 high school and 667 university students) completed a questionnaire. Exploratory factor analysis identified three distinct factors labeled "Acceptance" (6 items), "Psychological control" (6 items) and "Parental monitoring" (3 items). Confirmatory factor analysis demonstrated the stability of the factor structure with adequate goodness of fit indices. The three subscales of PAS had adequate internal consistency and satisfactory test-retest reliability. The three scales also correlated significantly with measures of adolescent conduct problems, peer problems, risk-taking experience, prosocial behavior, self-esteem, and another parenting scale, which indicated construct and concurrent validity. The practical use of the PAS was discussed. PMID:24063150

  7. Technician Checks Soil Sampler on Viking Lander

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A technician checks the soil sampler of the Viking lander. An arm will scoop up a sample of the Martian soil, empty it into a hopper on the lander which will route the sample to each of the three scientific instruments, biology, gas chromatograph/mass spectrometer and water analysis. NASA's Viking Lander was designed, fabricated, and tested by the Martin Marietta Corp. of Denver, Colorado, under the direction of the Viking Progect Office at Langley Research Center, Hampton, Virginia. The Lander drew heavily on the experience gained from the Ranger, Surveyor and the Apollo Programs in the areas of radar, altimeters, facsimile, cameras, soil samplers, landing gear, etc.

  8. Touch and Go Surface Sampler (TGSS)

    NASA Technical Reports Server (NTRS)

    Gorevan, S. P.; Rafeek, S.

    2001-01-01

    The Touch and Go Surface Sampler (TGSS) is a new class of planetary and small body sample acquisition tool that can be used for the surface exploration of Europa, Titan and comets. TGSS in its basic configuration consists of a high speed sampling head attached to the end of a flexible shaft. The sampling head consists of counter rotating cutters that rotates at speeds of 3000 to 15000 RPM. The attractive feature of this if touch and go type sampler is that there are no requirements for a lander type spacecraft. Additional information is contained in the original extended abstract.

  9. A comparison of the performance of samplers for respirable dust in workplaces and laboratory analysis for respirable quartz.

    PubMed

    Verpaele, Steven; Jouret, Jonathan

    2013-01-01

    The divergent sampling techniques for respirable dust and the analyses for crystalline silica are an important area of interest and discussion among industrial occupational hygienists in Europe. The variety of equipment for air sampling, methods and instrumentation can cause differences between results for the analysis of respirable crystalline silica (RCS). In this study, a Workplace Atmosphere Multi-sampler (WAM), developed by Adhesia, was used to compare respirable dust samplers in the workplace. This rotating device enables the comparison of 12 samplers in a workplace in each run. Seven laboratories participated in the comparison, using six different respirable dust samplers [British Cast Iron Research Association (BCIRA) to the Higgins Dewell (HD) design, Dorr Oliver, Casella SIMPEDS, SKC HD with a polycarbonate filter and polyvinylchloride filter, and the CIP10-R). Each laboratory analysed samples supplied by the samplers and reported the total respirable dust concentration and the RCS concentration. The techniques used were X-ray diffraction direct-on-filter, X-ray diffraction with deposition, infrared direct-on-filter, and infrared with potassium bromide (KBr) discs. The experiments were carried out in four different industries (enamel, sand extraction, foundry and brickworks). Generally, the SKC conductive black plastic sampler is oversampled (y = 1.52x + 0.008) and the CIP10 is undersampled (y = 0.74x + 0.068) when compared with the median air concentration. A pair-wise comparison of the different industries using t-tests indicated significant differences (P < 0.05) between the SKC conductive plastic samplers and the other samplers. The same series of statistical calculations were performed for the results obtained for RCS (quartz) and showed significant differences for the CIP10 techniques and the SKC conductive plastic cyclone analyses when using a polyvinylchloride filter. PMID:22826536

  10. Competitive concerns bring PAs, NPs into triage area.

    PubMed

    2008-06-01

    The ED at Harborview Medical Center in Seattle has proven new competition doesn't have to mean a loss of business or staff members. They moved physician assistants (PAs) and nurse practitioners (NPs) into triage to compete with urgent care clinics. When you have a hard time attracting midlevel practitioners, examine the local market to see who is recruiting them. Create a small, separate area in triage where midlevel practitioners can treat patients with less serious conditions. Be flexible with the number of hours the PAs and NPs work. Be prepared to expand their hours as demand increases. PMID:18807298

  11. A new sampler for stratified lagoon chemical and microbiological assessments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A water column sampler was needed to study stratification of nutrients and bacteria in a swine manure lagoon. Conventional samplers yielded shallow samples near the bank or required a boat. These limitations prompted development of a new sampler to collect at multiple depths with minimal disturbanc...

  12. 21 CFR 884.1560 - Fetal blood sampler.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fetal blood sampler. 884.1560 Section 884.1560... § 884.1560 Fetal blood sampler. (a) Identification. A fetal blood sampler is a device used to obtain fetal blood transcervically through an endoscope by puncturing the fetal skin with a short blade...

  13. 21 CFR 884.1560 - Fetal blood sampler.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Fetal blood sampler. 884.1560 Section 884.1560... § 884.1560 Fetal blood sampler. (a) Identification. A fetal blood sampler is a device used to obtain fetal blood transcervically through an endoscope by puncturing the fetal skin with a short blade...

  14. 21 CFR 884.1560 - Fetal blood sampler.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Fetal blood sampler. 884.1560 Section 884.1560... § 884.1560 Fetal blood sampler. (a) Identification. A fetal blood sampler is a device used to obtain fetal blood transcervically through an endoscope by puncturing the fetal skin with a short blade...

  15. 21 CFR 884.1560 - Fetal blood sampler.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fetal blood sampler. 884.1560 Section 884.1560... § 884.1560 Fetal blood sampler. (a) Identification. A fetal blood sampler is a device used to obtain fetal blood transcervically through an endoscope by puncturing the fetal skin with a short blade...

  16. 21 CFR 884.1560 - Fetal blood sampler.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Fetal blood sampler. 884.1560 Section 884.1560... § 884.1560 Fetal blood sampler. (a) Identification. A fetal blood sampler is a device used to obtain fetal blood transcervically through an endoscope by puncturing the fetal skin with a short blade...

  17. 21 CFR 884.1550 - Amniotic fluid sampler (amniocentesis tray).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Amniotic fluid sampler (amniocentesis tray). 884... Diagnostic Devices § 884.1550 Amniotic fluid sampler (amniocentesis tray). (a) Identification. The amniotic fluid sampler (amniocentesis tray) is a collection of devices used to aspirate amniotic fluid from...

  18. 21 CFR 884.1550 - Amniotic fluid sampler (amniocentesis tray).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Amniotic fluid sampler (amniocentesis tray). 884... Diagnostic Devices § 884.1550 Amniotic fluid sampler (amniocentesis tray). (a) Identification. The amniotic fluid sampler (amniocentesis tray) is a collection of devices used to aspirate amniotic fluid from...

  19. 21 CFR 884.1550 - Amniotic fluid sampler (amniocentesis tray).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Amniotic fluid sampler (amniocentesis tray). 884... Diagnostic Devices § 884.1550 Amniotic fluid sampler (amniocentesis tray). (a) Identification. The amniotic fluid sampler (amniocentesis tray) is a collection of devices used to aspirate amniotic fluid from...

  20. 21 CFR 884.1550 - Amniotic fluid sampler (amniocentesis tray).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Amniotic fluid sampler (amniocentesis tray). 884... Diagnostic Devices § 884.1550 Amniotic fluid sampler (amniocentesis tray). (a) Identification. The amniotic fluid sampler (amniocentesis tray) is a collection of devices used to aspirate amniotic fluid from...

  1. 21 CFR 884.1550 - Amniotic fluid sampler (amniocentesis tray).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Amniotic fluid sampler (amniocentesis tray). 884... Diagnostic Devices § 884.1550 Amniotic fluid sampler (amniocentesis tray). (a) Identification. The amniotic fluid sampler (amniocentesis tray) is a collection of devices used to aspirate amniotic fluid from...

  2. Student Sampler: Facts in Brief on North Carolina.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh.

    This information sampler was compiled to assist students in their study of North Carolina. Every year North Carolina students must complete a special project on their state. The sampler was designed to introduce students to the people, places, and events that have shaped North Carolina's history. Topics in the sampler include state symbols,…

  3. Quantum Gibbs Samplers: The Commuting Case

    NASA Astrophysics Data System (ADS)

    Kastoryano, Michael J.; Brandão, Fernando G. S. L.

    2016-06-01

    We analyze the problem of preparing quantum Gibbs states of lattice spin Hamiltonians with local and commuting terms on a quantum computer and in nature. Our central result is an equivalence between the behavior of correlations in the Gibbs state and the mixing time of the semigroup which drives the system to thermal equilibrium (the Gibbs sampler). We introduce a framework for analyzing the correlation and mixing properties of quantum Gibbs states and quantum Gibbs samplers, which is rooted in the theory of non-commutative {mathbb{L}_p} spaces. We consider two distinct classes of Gibbs samplers, one of them being the well-studied Davies generator modelling the dynamics of a system due to weak-coupling with a large Markovian environment. We show that their spectral gap is independent of system size if, and only if, a certain strong form of clustering of correlations holds in the Gibbs state. Therefore every Gibbs state of a commuting Hamiltonian that satisfies clustering of correlations in this strong sense can be prepared efficiently on a quantum computer. As concrete applications of our formalism, we show that for every one-dimensional lattice system, or for systems in lattices of any dimension at temperatures above a certain threshold, the Gibbs samplers of commuting Hamiltonians are always gapped, giving an efficient way of preparing the associated Gibbs states on a quantum computer.

  4. Ohio Sampler: Outdoor and Environmental Education.

    ERIC Educational Resources Information Center

    Ballbach, Joann, Ed.

    This document provides practical suggestions and meaningful activities for implementing Ohio's model curriculum in science for instruction that emphasizes hands-on experience and diverse learning opportunities. It also includes a variety of nonscience activities that emphasize and utilize the outdoors. This Sampler lists activities by indoor or…

  5. Releasable Asbestos Field Sampler (RAFS) Operation Manual

    EPA Science Inventory

    The Releasable Asbestos Field Sampler (RAFS) is a field instrument that provides an in-situ measurement of asbestos releasability from consistent and reproducible mechanical agitation of the source material such as soil. The RAFS was designed to measure concentration (asbestos st...

  6. Retained Gas Sampler Calibration and Simulant Tests

    SciTech Connect

    CRAWFORD, B.A.

    2000-01-05

    This test plan provides a method for calibration of the retained gas sampler (RGS) for ammonia gas analysis. Simulant solutions of ammonium hydroxide at known concentrations will be diluted with isotopically labeled 0.04 M ammonium hydroxide solution. Sea sand solids will also be mixed with ammonium hydroxide solution and diluent to determine the accuracy of the system for ammonia gas analysis.

  7. A Personal Nanoparticle Respiratory Deposition (NRD) Sampler

    PubMed Central

    Cena, Lorenzo G.; Anthony, T. Renée; Peters, Thomas M.

    2016-01-01

    A lightweight (60 g), personal nanoparticle respiratory deposition (NRD) sampler was developed to selectively collect particles smaller than 300 nm similar to their typical deposition in the respiratory tract. The sampler operates at 2.5 Lpm and consists of a respirable cyclone fitted with an impactor and a diffusion stage containing mesh screens. The cut-point diameter of the impactor was determined to be 300 nm with a sharpness σ = 1.53. The diffusion stage screens collect particles with an efficiency that matches the deposition efficiency of particles smaller than 300 nm in the respiratory tract. Impactor separation performance was unaffected by loading at typical workplace levels (p-value = 0.26). With chemical analysis of the diffusion media, the NRD sampler can be used to directly assess exposures to nanoparticles of a specific composition apart from other airborne particles. The pressure drop of the NRD sampler is sufficiently low to permit its operation with conventional, belt-mounted sampling pumps. PMID:21718022

  8. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one of the most wood-smoke-polluted cities in Chile: The case study of Temuco.

    PubMed

    Pozo, Karla; Estellano, Victor H; Harner, Tom; Diaz-Robles, Luis; Cereceda-Balic, Francisco; Etcharren, Pablo; Pozo, Katerine; Vidal, Victor; Guerrero, Fabián; Vergara-Fernández, Alberto

    2015-09-01

    This study addresses human health concerns in the city of Temuco that are attributed to wood smoke and related pollutants associated with wood burning activities that are prevalent in Temuco. Polycyclic Aromatic Hydrocarbons (PAHs) were measured in air across urban and rural sites over three seasons in Temuco using polyurethane foam (PUF) disk passive air samplers (PUF-PAS). Concentrations of ΣPAHs (15 congeners) in air ranged from BDL to ∼70 ng m(-3) and were highest during the winter season, which is attributed to emissions from residential heating by wood combustion. The results for all three seasons showed that the PAH plume was widespread across all sites including rural sites on the outskirts of Temuco. Some interesting variations were observed between seasons in the composition of PAHs, which were attributed to differences in seasonal point sources. A comparison of the PAH composition in the passive samples with active samples (gas+particle phase) from the same site revealed similar congener profiles. Overall, the study demonstrated that the PUF disk passive air sampler provides a simple approach for measuring PAHs in air and for tracking effectiveness of pollution control measures in urban areas in order to improve public health.

  9. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one of the most wood-smoke-polluted cities in Chile: The case study of Temuco.

    PubMed

    Pozo, Karla; Estellano, Victor H; Harner, Tom; Diaz-Robles, Luis; Cereceda-Balic, Francisco; Etcharren, Pablo; Pozo, Katerine; Vidal, Victor; Guerrero, Fabián; Vergara-Fernández, Alberto

    2015-09-01

    This study addresses human health concerns in the city of Temuco that are attributed to wood smoke and related pollutants associated with wood burning activities that are prevalent in Temuco. Polycyclic Aromatic Hydrocarbons (PAHs) were measured in air across urban and rural sites over three seasons in Temuco using polyurethane foam (PUF) disk passive air samplers (PUF-PAS). Concentrations of ΣPAHs (15 congeners) in air ranged from BDL to ∼70 ng m(-3) and were highest during the winter season, which is attributed to emissions from residential heating by wood combustion. The results for all three seasons showed that the PAH plume was widespread across all sites including rural sites on the outskirts of Temuco. Some interesting variations were observed between seasons in the composition of PAHs, which were attributed to differences in seasonal point sources. A comparison of the PAH composition in the passive samples with active samples (gas+particle phase) from the same site revealed similar congener profiles. Overall, the study demonstrated that the PUF disk passive air sampler provides a simple approach for measuring PAHs in air and for tracking effectiveness of pollution control measures in urban areas in order to improve public health. PMID:26022137

  10. Site comparison of selected aerosol samplers in the wood industry.

    PubMed

    Kauffer, Edmond; Wrobel, Richard; Görner, Peter; Rott, Christelle; Grzebyk, Michel; Simon, Xavier; Witschger, Olivier

    2010-03-01

    Several samplers (IOM, CIP 10-I v1, ACCU-CAP, and Button) were evaluated at various wood industry companies using the CALTOOL system. The results obtained show that compared to the CALTOOL mouth, which can be considered to be representative of the exposure of a person placed at the same location under the same experimental conditions, the concentrations measured by the IOM, CIP 10-I v1, and ACCU-CAP samplers are not significantly different (respectively, 1.12, 0.94, and 0.80 compared to 1.00), the Button sampler (0.86) being close to the ACCU-CAP sampler. Comparisons of dust concentrations measured using both a closed-face cassette (CFC) and one of the above samplers were also made. In all, 235 sampling pairs (sampler + CFC) taken at six companies provided us with a comparison of concentrations measured using IOM, CIP 10-I v1, ACCU-CAP, and Button samplers with concentrations measured using a CFC. All the studied samplers collected systematically more dust than the CFC (2.0 times more for the IOM sampler, 1.84 times more for the CIP 10-I v1 sampler, 1.68 times more for the ACCU-CAP sampler, and 1.46 times more for the Button sampler). The literature most frequently compares the IOM sampler with the CFC: published results generally show larger differences compared with the CFC than those found during our research. There are several explanations for this difference, one of which involves CFC orientation during sampling. It has been shown that concentrations measured using a CFC are dependent on its orientation. Different CFC positions from one sampling session to another are therefore likely to cause differences during CFC-IOM sampler comparisons.

  11. Three-Wheel Brush-Wheel Sampler

    NASA Technical Reports Server (NTRS)

    Duckworth, Geoffrey A.; Liu, Jun; Brown, Mark G.

    2010-01-01

    A new sampler is similar to a common snow blower, but is robust and effective in sample collection. The brush wheels are arranged in a triangle shape, each driven by a brushless DC motor and planetary gearhead embedded in the wheel shaft. Its speed can be varied from 800 - 2,000 rpm, depending on the surface regolith resistance. The sample-collecting flow path, and internal features, are designed based on flow dynamics, and the sample-collecting rates have consistently exceeded the requirement under various conditions that span the range of expected surface properties. The brush-wheel sampler (BWS) is designed so that the flow channel is the main body of the apparatus, and links the brush-wheel assembly to the sample canister. The combination of the three brush wheels, the sample flow path, and the canister location make sample collection, storage, and transfer an easier task.

  12. Photodegradation of PAHs in passive water samplers.

    PubMed

    Allan, Ian J; Christensen, Guttorm; Bæk, Kine; Evenset, Anita

    2016-04-15

    Losses of deuterated polycyclic aromatic hydrocarbons (PAHs) used as performance reference compounds (PRCs) in semipermeable membrane devices deployed at fifteen coastal sampling sites near Harstad harbour in Northern Norway were used to investigate photodegradation of these photosensitive compounds. Unusual PRC dissipation profiles, especially for samplers exposed <5m below the water surface are indicative of photodegradation. A strong correlation between loss rates for d12-chrysene and d12-benzo[e]pyrene with consistently higher losses of the latter was found. The observed photodegradation rates may be sufficiently high to impact PAH masses absorbed by a factor of two. This study demonstrates that photodegradation during exposure of passive water samplers needs to be taken into account, particularly with deployments close to the water surface, when using SPMD canisters, or when sampling in the Arctic. PMID:26876557

  13. Marketing and medicine. A basic guide for PAs.

    PubMed

    Blessing, J D; Davis, N L

    1988-07-01

    Marketing is a conscious plan to influence the behavior of others. Physician assistants can use marketing techniques to promote themselves and their profession as well as to help build a practice and improve patient services. Basic components of a marketing strategy include analysis, planning, implementation, and monitoring. Marketing tools easily accessible to PAs are the telephone (call to check on compliance); a photocopy machine (patient handouts and practice newsletters); and the mail (postcard to remind of follow-up visit).

  14. Procedures and acceptance criteria for PAS-1 cask inspections

    SciTech Connect

    Mercado, J.E.

    1998-09-09

    The procedures and acceptance criteria that comprise this document were prepared to support a one-time test to certify two PAS-1 casks in accordance with US Department of Energy Certificate of Compliance US A/9184/B(U), which was issued in 1998. The specific inspections addressed in this document are the visual weld inspection and a dimensional inspection of the primary containment vessel.

  15. Mapping a Discharge Zone of Arsenic-Contaminated Ground Water Using Diffusion Samplers

    NASA Astrophysics Data System (ADS)

    Vroblesky, D. A.

    2001-05-01

    Arsenic, iron, and manganese are present at elevated concentrations in ground water at the Naval Air Station Fort Worth Joint Reserve Base in Texas. The source of the metals is thought to be mobilization from naturally occurring minerals as a result of reducing conditions produced by petroleum hydrocarbon degradation. Previous work showed that the metals are in a plume oriented along the ground-water flowpath toward an unnamed tributary of the Trinity River. Concentrations of arsenic in ground water at wells within the plume range from about 75 micrograms per liter (mg/L) in upgradient areas to about 4 mg/L near the tributary. Eight diffusion samplers, each consisting of anaerobic deionized water in a 25 milliliter plastic jar with 250-micron nylon mesh covering the mouth were buried in bottom sediment of the unnamed tributary along a 200-foot (ft) reach. Arsenic was not detected in the samplers at 0 and 200 ft and was at concentrations less than 15 mg/L in the samplers at 93 and 153 ft along the traverse. However, arsenic concentrations in excess of 50 mg/L were found in the 60-ft reach between 93 and 153 ft, coinciding with the projected discharge point of the ground-water arsenic plume. Iron also was elevated in this zone as well as in the contaminated ground water. The data show that this type of diffusion sampler is an effective tool for mapping zones where metals-containing ground-water discharge to surface water

  16. Thin layer chromatography residue applicator sampler

    DOEpatents

    Nunes, Peter J.; Kelly, Fredrick R.; Haas, Jeffrey S.; Andresen, Brian D.

    2007-07-24

    A thin layer chromatograph residue applicator sampler. The residue applicator sampler provides for rapid analysis of samples containing high explosives, chemical warfare, and other analyses of interest under field conditions. This satisfied the need for a field-deployable, small, hand-held, all-in-one device for efficient sampling, sample dissolution, and sample application to an analytical technique. The residue applicator sampler includes a sampling sponge that is resistant to most chemicals and is fastened via a plastic handle in a hermetically sealed tube containing a known amount of solvent. Upon use, the wetted sponge is removed from the sealed tube and used as a swiping device across an environmental sample. The sponge is then replaced in the hermetically sealed tube where the sample remains contained and dissolved in the solvent. A small pipette tip is removably contained in the hermetically sealed tube. The sponge is removed and placed into the pipette tip where a squeezing-out of the dissolved sample from the sponge into the pipette tip results in a droplet captured in a vial for later instrumental analysis, or applied directly to a thin layer chromatography plate for immediate analysis.

  17. Formed Core Sampler Hydraulic Conductivity Testing

    SciTech Connect

    Miller, D. H.; Reigel, M. M.

    2012-09-25

    A full-scale formed core sampler was designed and functionally tested for use in the Saltstone Disposal Facility (SDF). Savannah River National Laboratory (SRNL) was requested to compare properties of the formed core samples and core drilled samples taken from adjacent areas in the full-scale sampler. While several physical properties were evaluated, the primary property of interest was hydraulic conductivity. Differences in hydraulic conductivity between the samples from the formed core sampler and those representing the bulk material were noted with respect to the initial handling and storage of the samples. Due to testing conditions, the site port samples were exposed to uncontrolled temperature and humidity conditions prior to testing whereas the formed core samples were kept in sealed containers with minimal exposure to an uncontrolled environment prior to testing. Based on the results of the testing, no significant differences in porosity or density were found between the formed core samples and those representing the bulk material in the test stand.

  18. Performance of High Flow Rate Personal Respirable Samplers When Challenged with Mineral Aerosols of Different Particle Size Distributions.

    PubMed

    Stacey, Peter; Thorpe, Andrew; Echt, Alan

    2016-05-01

    It is thought that the performance of respirable samplers may vary when exposed to dust aerosols with different particle sizes and wind speeds. This study investigated the performance of the GK 4.16 (RASCAL), GK 2.69, PPI 8, and FSP 10, high flow rate personal samplers when exposed to aerosols of mineral dust in a wind tunnel at two different wind speeds (1 and 2 m s(-1)) and orientations (towards and side-on to the source of emission). The mass median aerodynamic diameter of four aerosolized test dusts ranged from 8 to 25 µm with geometric standard deviations from 1.6 to 2 µm. The performance of each sampler type was compared with that of the SIMPEDS (Higgins-Dewell design) sampler. There was slight evidence to suggest that the performance of the FSP 10 is affected by the direction of the inlet relative to the air flow, although this was not significant when most respirable dust concentrations were compared, possibly due to the variability of paired dust concentration results. The GK 2.69, RASCAL, and PPI 8 samplers had similar performances, although the results when side-on to the emission source were generally slightly lower than the SIMPEDS. Despite slight differences between respirable dust concentrations the respirable crystalline silica values were not significantly different from the SIMPEDS. The GK family of cyclones obtained most precise results and more closely matched the SIMPEDS. A comparison with dust concentration results from previous calm air chamber studies (where wind speeds were < 0.4 m s(-1)) found that the relative performance between samplers was similar to those observed in this work indicating consistent performance relative to the SIMPEDS in both calm and moving air. PMID:26865560

  19. Performance of High Flow Rate Personal Respirable Samplers When Challenged with Mineral Aerosols of Different Particle Size Distributions

    PubMed Central

    Stacey, Peter; Thorpe, Andrew; Echt, Alan

    2016-01-01

    It is thought that the performance of respirable samplers may vary when exposed to dust aerosols with different particle sizes and wind speeds. This study investigated the performance of the GK 4.16 (RASCAL), GK 2.69, PPI 8, and FSP 10, high flow rate personal samplers when exposed to aerosols of mineral dust in a wind tunnel at two different wind speeds (1 and 2 m s−1) and orientations (towards and side-on to the source of emission). The mass median aerodynamic diameter of four aerosolized test dusts ranged from 8 to 25 µm with geometric standard deviations from 1.6 to 2 µm. The performance of each sampler type was compared with that of the SIMPEDS (Higgins–Dewell design) sampler. There was slight evidence to suggest that the performance of the FSP 10 is affected by the direction of the inlet relative to the air flow, although this was not significant when most respirable dust concentrations were compared, possibly due to the variability of paired dust concentration results. The GK 2.69, RASCAL, and PPI 8 samplers had similar performances, although the results when side-on to the emission source were generally slightly lower than the SIMPEDS. Despite slight differences between respirable dust concentrations the respirable crystalline silica values were not significantly different from the SIMPEDS. The GK family of cyclones obtained most precise results and more closely matched the SIMPEDS. A comparison with dust concentration results from previous calm air chamber studies (where wind speeds were < 0.4 m s−1) found that the relative performance between samplers was similar to those observed in this work indicating consistent performance relative to the SIMPEDS in both calm and moving air. PMID:26865560

  20. A miniature flexible sampler for subsurface lunar exploration

    NASA Astrophysics Data System (ADS)

    Ling, Yun; Lu, Wei; Xiong, Pengwen; Song, Aiguo

    2016-06-01

    Lunar subsurface sampling is one of the critical technologies in the advancement of space exploration, and a lunar sampler with low weight, small volume, and low power consumption would significantly reduce the cost of space exploration. Thus, this paper proposes a novel miniature lunar sampler which adopts a flexible tape spring as its sampling arm. Compared with existing rigid-arm samplers, the proposed sampler has the merits of very low weight, reduced volume, and little power consumption. The mechanical design is illustrated in detail, the corresponding flexible kinematics model is built by considering flexibility compensation, and the working space of the sampler is depicted. The performance, e.g. the maximum acceleration, the maximum load capacity, and the sampling depth of the flexible arm, is analyzed through experiments, and each limit is established. In addition, the sampling process is demonstrated with the lab-based experiments, and the feasibility of the sampler is verified.

  1. High volume electrostatic field-sampler for collection of fine particle bulk samples

    NASA Astrophysics Data System (ADS)

    Kumar Sharma, Anoop; Wallin, Håkan; Alstrup Jensen, Keld

    A high volume electrostatic field-sampler was developed for collection of fine particles, which easily can be recovered for subsequent sample characterisation and bioassays. The sampler was based on a commercial office air cleaner and consisted of a prefilter followed by electrostatic collection plates operating at 2.7 kV. The sampler performance was characterised for 26 nm to 5.4 μm-size particles in urban street air. The collection efficiency reached a maximum (60-70%) between 0.2 and 0.8 μm and dropped to ˜25% at 30 nm and 2.5 μm, respectively. After extraction in water, the particle loss was<2%. The extraction efficiency for dry lyophilised particulate matter was above 80%, allowing retrievement of ˜12 mg day -1 in urban street air at PM 10 levels of ˜24 μg m -3. The ozone generating capacity of the corona discharge during operation was on the order of 10 ppb. A polycyclic aromatic hydrocarbons (PAH) degradation test using benzo[a]pyrene as a model showed that ˜85% was degraded after 24 h. However, similar results were observed when the corona discharge was switched off. Hence, the ozone and other corona discharge reactants do not appear to contribute considerably to PAH-degradation. The overall results show that the sampler type is a promising alternative to traditional sampling of fine particles for bulk analysis and bioassays. The main advantages are simple operation, high stability, high quantifiable particle recovery rates and low cost.

  2. Advances in PAS-2 thermoplastic prepregs and composites

    SciTech Connect

    Lee, D.M.; Register, D.F.; Lindstrom, M.R.; Campbell, R.W.

    1988-04-01

    A family of polyarylene sulfide polymers is being developed as thermoplastic engineering resins. These resins have high temperature mechanical performance, good mechanical strength, and good solvent resistance. The newest member of this family of resins is PAS-2 amorphous polyarylene sulfide. One potential application for this amorphous resin is as a matrix for high performance composites. The amorphous polyarylene sulfide resin has been formed into unidirectional prepreg tapes. These tapes have been molded into laminates of excellent quality. Recently, new levels of performance in mechanical properties and processing have been achieved.

  3. Geodynamic Research at the Department of Planetary Geodesy, SRC PAS

    NASA Astrophysics Data System (ADS)

    Brzeziński, Aleksander; Jóźwik, Mieczysław; Kaczorowski, Marek; Kalarus, Maciej; Kasza, Damian; Kosek, Wiesław; Nastula, Jolanta; Szczerbowski, Zbigniew; Wińska, Małgorzata; Wronowski, Roman; Zdunek, Ryszard; Zieliński, Janusz B.

    2016-06-01

    The Department of Planetary Geodesy of the Space Research Centre PAS has been conducting research on a broad spectrum of problems within a field of global dynamics of the Earth. In this report we describe the investigations on selected subjects concerning polar motion (modeling and geophysical interpretation of the Chandler wobble, hydrological excitation of seasonal signals, search for optimal prediction methods), tectonic activity in the region of the Książ Geodynamic Laboratory of the SRC, and finally the new joint Polish-Italian project GalAc analyzing feasibility and usefulness of equipping second-generation Galileo satellites with accelerometers.

  4. Comparison of water-quality samples collected by siphon samplers and automatic samplers in Wisconsin

    USGS Publications Warehouse

    Graczyk, David J.; Robertson, Dale M.; Rose, William J.; Steur, Jeffrey J.

    2000-01-01

    In small streams, flow and water-quality concentrations often change quickly in response to meteorological events. Hydrologists, field technicians, or locally hired stream ob- servers involved in water-data collection are often unable to reach streams quickly enough to observe or measure these rapid changes. Therefore, in hydrologic studies designed to describe changes in water quality, a combination of manual and automated sampling methods have commonly been used manual methods when flow is relatively stable and automated methods when flow is rapidly changing. Auto- mated sampling, which makes use of equipment programmed to collect samples in response to changes in stage and flow of a stream, has been shown to be an effective method of sampling to describe the rapid changes in water quality (Graczyk and others, 1993). Because of the high cost of automated sampling, however, especially for studies examining a large number of sites, alternative methods have been considered for collecting samples during rapidly changing stream conditions. One such method employs the siphon sampler (fig. 1). also referred to as the "single-stage sampler." Siphon samplers are inexpensive to build (about $25- $50 per sampler), operate, and maintain, so they are cost effective to use at a large number of sites. Their ability to collect samples representing the average quality of water passing though the entire cross section of a stream, however, has not been fully demonstrated for many types of stream sites.

  5. Retained gas sampler interim safety assessment

    SciTech Connect

    Pasamehmetoglu, K.O.; Miller, W.O.; Unal, C.; Fujita, R.K.

    1995-01-13

    This safety assessment addresses the proposed action to install, operate, and remove a Retained Gas Sampler (RGS) in Tank 101-SY at Hanford. Purpose of the RGS is to help characterize the gas species retained in the tank waste; the information will be used to refine models that predict the gas-producing behavior of the waste tank. The RGS will take samples of the tank from top to bottom; these samples will be analyzed for gas constituents. The proposed action is required as part of an evaluation of mitigation concepts for eliminating episodic gas releases that result in high hydrogen concentrations in the tank dome space.

  6. Application of flow cytometry for the assessment of preservation and recovery efficiency of bioaerosol samplers spiked with Pantoea agglomerans.

    PubMed

    Rule, Ana M; Kesavan, Jana; Schwab, Kellogg J; Buckley, Timothy J

    2007-04-01

    Exposure assessment of biological aerosols requires trade-offs between efficient sampling of airborne microorganisms as either particles or viable units. The main objective of this work was to characterize aspects of bioaerosol measurement efficiency. A known concentration of the vegetative bacteria Pantoea agglomerans was spiked onto different samplers (AGI-30, BioSampler, and membrane filters) and then run for increasing time periods using HEPA filtered air. Measurement efficiency was evaluated based on total, viable, and culturable counts. Total and viable counts were determined by flow-cytometry (FCM); culturable counts were evaluated by standard plating. FCM as a method for assaying viability showed excellent agreement with known proportions of live/dead organisms (slope = 0.82, R(2) = 0.99). P. agglomerans recoveries (total, viable, and culturable) in order of best sampler performance included the BioSampler (75%, 52%, and 50%), filtration (50%, 13%, and 2%), and the AGI-30 (<30%, 15%, and 5%). The difference between viability and culturability provided an indication of viable but nonculturable (VBNC) cells. VBNC efficiency for sampling by filter, AGI-30, and BioSampler was 80%, 50%, and 100%, respectively. This research helps characterize recovery, survival, and culturability efficiencies while sampling environmentally sensitive airborne bacteria for purposes of exposure assessment, epidemiologic studies, and homeland security. PMID:17438801

  7. Rapid detection of airborne viruses by personal bioaerosol sampler combined with the PCR device

    NASA Astrophysics Data System (ADS)

    Agranovski, I. E.; Safatov, A. S.; Sergeev, A. A.; Pyankov, O. V.; Petrishchenko, V. A.; Mikheev, M. V.; Sergeev, A. N.

    A new personal sampler had been previously developed and verified for monitoring of viable airborne viruses. The aims of this project were to investigate a possibility of the utilization of the polymerase chain reaction (PCR) method to speed up the time consuming analytical procedures and to evaluate a lower detection limit of the combined (sampler-PCR) device. Tenfold serial dilutions of the initial suspension of the Vaccinia virus were aerosolized in the chamber and airborne viruses were monitored by two simultaneously operating samplers. The results of monitoring were successfully obtained by a standard plaque assay (live microbes) and by the PCR method (total DNA). The corresponding calculations to identify the minimal detectable concentration in the ambient air were then performed. It was found that the minimal detectable concentration of airborne viruses in the ambient air depends on the sampling time. As demonstrated, such concentration should be at least 125×10 3 PFU m -3 for a sampling time of as short as 1 min. The detectable concentration decreases with the increase of the sampling time and reaches 25×10 3 and 10×10 3 PFU m -3 for 5 and 12.5 min of sampling respectively.

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

    ERIC Educational Resources Information Center

    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)

  9. Silicone Wristbands as Personal Passive Samplers

    PubMed Central

    2014-01-01

    Active-sampling approaches are commonly used for personal monitoring, but are limited by energy usage and data that may not represent an individual’s exposure or bioavailable concentrations. Current passive techniques often involve extensive preparation, or are developed for only a small number of targeted compounds. In this work, we present a novel application for measuring bioavailable exposure with silicone wristbands as personal passive samplers. Laboratory methodology affecting precleaning, infusion, and extraction were developed from commercially available silicone, and chromatographic background interference was reduced after solvent cleanup with good extraction efficiency (>96%). After finalizing laboratory methods, 49 compounds were sequestered during an ambient deployment which encompassed a diverse set of compounds including polycyclic aromatic hydrocarbons (PAHs), consumer products, personal care products, pesticides, phthalates, and other industrial compounds ranging in log Kow from −0.07 (caffeine) to 9.49 (tris(2-ethylhexyl) phosphate). In two hot asphalt occupational settings, silicone personal samplers sequestered 25 PAHs during 8- and 40-h exposures, as well as 2 oxygenated-PAHs (benzofluorenone and fluorenone) suggesting temporal sensitivity over a single work day or week (p < 0.05, power =0.85). Additionally, the amount of PAH sequestered differed between worksites (p < 0.05, power = 0.99), suggesting spatial sensitivity using this novel application. PMID:24548134

  10. Silicone wristbands as personal passive samplers.

    PubMed

    O'Connell, Steven G; Kincl, Laurel D; Anderson, Kim A

    2014-03-18

    Active-sampling approaches are commonly used for personal monitoring, but are limited by energy usage and data that may not represent an individual's exposure or bioavailable concentrations. Current passive techniques often involve extensive preparation, or are developed for only a small number of targeted compounds. In this work, we present a novel application for measuring bioavailable exposure with silicone wristbands as personal passive samplers. Laboratory methodology affecting precleaning, infusion, and extraction were developed from commercially available silicone, and chromatographic background interference was reduced after solvent cleanup with good extraction efficiency (>96%). After finalizing laboratory methods, 49 compounds were sequestered during an ambient deployment which encompassed a diverse set of compounds including polycyclic aromatic hydrocarbons (PAHs), consumer products, personal care products, pesticides, phthalates, and other industrial compounds ranging in log K(ow) from -0.07 (caffeine) to 9.49 (tris(2-ethylhexyl) phosphate). In two hot asphalt occupational settings, silicone personal samplers sequestered 25 PAHs during 8- and 40-h exposures, as well as 2 oxygenated-PAHs (benzofluorenone and fluorenone) suggesting temporal sensitivity over a single work day or week (p < 0.05, power =0.85). Additionally, the amount of PAH sequestered differed between worksites (p < 0.05, power = 0.99), suggesting spatial sensitivity using this novel application. PMID:24548134

  11. VALIDATION OF A NEW SOIL VOC SAMPLER

    SciTech Connect

    Susan S. Sorini; John F. Schabron

    1997-04-01

    The overall objective of this project is to facilitate national acceptance of the EnCore{trademark} sampling/storage device by conducting product tests, method development, and method validation activities. The specific goals for the initial six-month period of the project are listed: (1) Evaluate and become familiar with the stainless steel EnCore{trademark} sampling/storage device for collecting and holding soil samples for determination of volatile organic compounds (VOCs); (2) Initiate interaction with American Society for Testing and Materials (ASTM) Committee D-34 on Waste Management to begin the ASTM standard preparation and approval process; (3) Prepare an ASTM drall practice for using a device fitting the description of the EnCore{trademark} sampler for sampling and storing soil for volatile organic analysis. Under ASTM guidelines, the procedure describing the use of a device, such as the EnCore{trademark} sampler, is referred to as a practice rather than a method because it is a definitive set of instructions for performing one or more specific operations that does not produce a test result (ASTM 1996a); and (4) Plan testing needed to establish maximum storage temperatures and times for inclusion in the ASTM practice.

  12. Automated syringe sampler. [remote sampling of air and water

    NASA Technical Reports Server (NTRS)

    Purgold, G. C. (Inventor)

    1981-01-01

    A number of sampling services are disposed in a rack which slides into a housing. In response to a signal from an antenna, the circutry elements are activated which provide power individually, collectively, or selectively to a servomechanism thereby moving an actuator arm and the attached jawed bracket supporting an evaculated tube towards a stationary needle. One open end of the needle extends through the side wall of a conduit to the interior and the other open end is maintained within the protective sleeve, supported by a bifurcated bracket. A septum in punctured by the end of the needle within the sleeve and a sample of the fluid medium in the conduit flows through the needle and is transferred to a tube. The signal to the servo is then reversed and the actuator arm moves the tube back to its original position permitting the septum to expand and seal the hole made by the needle. The jawed bracket is attached by pivot to the actuator to facilitate tube replacement.

  13. COMPARISON OF INTEGRATED SAMPLERS FOR MASS AND COMPOSITION

    EPA Science Inventory

    The primary objective of EPA's Atlanta Supersites Project was to compare and evaluate a wide variety of samplers from time-integrated mass only monitors, to integrated and semi-continuous chemical speciation samplers, to single particle mass spectrometers. This paper will desc...

  14. Discipline-Based Art Education: A Curriculum Sampler.

    ERIC Educational Resources Information Center

    Alexander, Kay, Ed.; Day, Michael, Ed.

    This sampler was designed for art specialists and art museum educators with a basic understanding of teaching discipline-based art education content. The introduction offers a brief history of the Sampler and explains its intended purpose and use. Then 8 unit models with differing methodologies for relating art objectives to the four disciplines:…

  15. Siting Samplers to Minimize Expected Time to Detection

    SciTech Connect

    Walter, Travis; Lorenzetti, David M.; Sohn, Michael D.

    2012-05-02

    We present a probabilistic approach to designing an indoor sampler network for detecting an accidental or intentional chemical or biological release, and demonstrate it for a real building. In an earlier paper, Sohn and Lorenzetti(1) developed a proof of concept algorithm that assumed samplers could return measurements only slowly (on the order of hours). This led to optimal detect to treat architectures, which maximize the probability of detecting a release. This paper develops a more general approach, and applies it to samplers that can return measurements relatively quickly (in minutes). This leads to optimal detect to warn architectures, which minimize the expected time to detection. Using a model of a real, large, commercial building, we demonstrate the approach by optimizing networks against uncertain release locations, source terms, and sampler characteristics. Finally, we speculate on rules of thumb for general sampler placement.

  16. Passive air sampling of organochlorine pesticides in a northeastern state of India, Manipur.

    PubMed

    Devi, Ningombam Linthoingambi; Qi, Shihua; Chakraborty, Paromita; Zhang, Gan; Yadav, Ishwar Chandra

    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 atmospheric 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.

  17. A high-yield sampler for toxicological characterization of complex mixtures in combustion effluents.

    PubMed Central

    Kruzel, E L; Lafleur, A L; Braun, A G; Longwell, J P; Thilly, W G; Peters, W A

    1991-01-01

    Combustion sampling for toxicological assessment often requires that large (greater than 100 mg) lots of complex organic mixtures of wide volatility range be rapidly recovered from high temperature gases without contamination. A new sampler, meeting these criteria for studies of public health interest, has been developed and demonstrated. The device provides high sampling rates and intimate contacting of the samples stream with large volumes of a well-cooled, liquid solvent, dichloromethane (DCM). This promotes rapid organics dissolution from carrier gas and particulates and prompt dilution and quenching of the resulting solution, resulting in high organics collection efficiencies with minimal DCM losses. Solvent separation then remits large quantities of concentrated organics for chemical analysis and toxicological testing. One- to seven-hour interrogations of in-flame, post-flame, and flue gas regions gave 50- to 250-mg yields of complex organic mixtures. In side-by-side sampling of combustion exhaust, the DCM sampler provided higher yields of DCM solubles (identified with complex organic mixtures) and of S. typhimuirim mutagens (active without exogenous metabolizing agents) than did a filter/polymeric sorbent bed sampling train. The new sampler also collects polar and high volatile hydrocarbons such as benzaheyde, pentadiyne, m- and p-diethynyl-benzene, and 1-hexen-3,5-diyne. Nitration of naphthalene and pyrene in DCM solution (1 mg/mL each) was less than 1 part in 10(7) after a 345-min exposure to a bubbling flow of moist N2/air mixture (1:1 v/v) containing 107 ppm NO and 1.5 ppm NO2, indicating that for these condition a DCM sampler should resist artifactual nitration of aromatics. However, because of the very high bacterial mutagenicity of some nitroaromatics and the wide range of sampling conditions of environmental interest, nitration and all artifacts must still be scrutinized when using the DCM sampler. The DCM sampler is expected to contribute to public

  18. Improving the Convergence of Reversible Samplers

    NASA Astrophysics Data System (ADS)

    Rey-Bellet, Luc; Spiliopoulos, Konstantinos

    2016-08-01

    In Monte-Carlo methods the Markov processes used to sample a given target distribution usually satisfy detailed balance, i.e. they are time-reversible. However, relatively recent results have demonstrated that appropriate reversible and irreversible perturbations can accelerate convergence to equilibrium. In this paper we present some general design principles which apply to general Markov processes. Working with the generator of Markov processes, we prove that for some of the most commonly used performance criteria, i.e., spectral gap, asymptotic variance and large deviation functionals, sampling is improved for appropriate reversible and irreversible perturbations of some initially given reversible sampler. Moreover we provide specific constructions for such reversible and irreversible perturbations for various commonly used Markov processes, such as Markov chains and diffusions. In the case of diffusions, we make the discussion more specific using the large deviations rate function as a measure of performance.

  19. Calibration of nylon organic chemical integrative samplers and sentinel samplers for quantitative measurement of pulsed aquatic exposures.

    PubMed

    Morrison, Shane A; Belden, Jason B

    2016-06-01

    Environmental exposures often occur through short, pulsed events; therefore, the ability to accurately measure these toxicologically-relevant concentrations is important. Three different integrative passive sampler configurations were evaluated under different flow and pulsed exposure conditions for the measurement of current-use pesticides (n=19), polyaromatic hydrocarbons (n=10), and personal care products (n=5) spanning a broad range of hydrophobicities (log Kow 1.5-7.6). Two modified POCIS-style samplers were investigated using macroporous nylon mesh membranes (35μm pores) and two different sorbent materials (i.e. Oasis HLB and Dowex Optipore L-493). A recently developed design, the Sentinel Sampler (ABS Materials), utilizing Osorb media enclosed within stainless steel mesh (145μm pores), was also investigated. Relatively high sampling rates (Rs) were achieved for all sampler configurations during the short eight-day exposure (4300-27mL/d). Under flow conditions, median Rs were approximately 5-10 times higher for POCIS-style samplers and 27 times higher for Sentinel Samplers, as compared to static conditions. The ability of samplers to rapidly measure hydrophobic contaminants may be a trade off with increased flow dependence. Analyte accumulation was integrative under pulsed and continuous exposures for POCIS-style samplers with mean difference between treatments of 11% and 33%; however, accumulation into Sentinel Samplers was more variable. Collectively, results show that reducing membrane limitations allows for rapid, integrative accumulation of a broad range of analytes even under pulsed exposures. As such, these sampler designs may be suitable for monitoring environmental substances that have short aquatic half-lives. PMID:27139214

  20. Acoustically enriching, large-depth aquatic sampler.

    PubMed

    Jonsson, Jonas; Ogden, Sam; Johansson, Linda; Hjort, Klas; Thornell, Greger

    2012-05-01

    In marine biology, it is useful to collect water samples when exploring the distribution and diversity of microbial communities in underwater environments. In order to provide, e.g., a miniaturized submersible explorer with the capability of collecting microorganisms, a compact sample enrichment system has been developed. The sampler is 30 mm long, 15 mm wide, and just a few millimetres thick. Integrated in a multilayer steel, polyimide and glass construction is a microfluidic channel with piezoelectric transducers, where microorganism and particle samples are collected and enriched, using acoustic radiation forces for gentle and labelless trapping. High-pressure, latchable valves, using paraffin as the actuation material, at each end of the microfluidic channel keep the collected sample pristine. A funnel structure raised above the surface of the device directs water into the microfluidic channel as the vehicle propels itself or when there is a flow across its hull. The valves proved leak proof to a pressure of 2.1 MPa for 19 hours and momentary pressures of 12.5 MPa, corresponding to an ocean depth of more than 1200 metres. By reactivating the latching mechanism, small leakages through the valves could be remedied, which could thus increase the leak-less operational time. Fluorescent particles, 1.9 μm in diameter, were successfully trapped in the microfluidic channel at flow rates up to 15 μl min(-1), corresponding to an 18.5 cm s(-1) external flow rate of the sampler. In addition, liquid-suspended GFP-marked yeast cells were successfully trapped.

  1. Acoustically enriching, large-depth aquatic sampler.

    PubMed

    Jonsson, Jonas; Ogden, Sam; Johansson, Linda; Hjort, Klas; Thornell, Greger

    2012-05-01

    In marine biology, it is useful to collect water samples when exploring the distribution and diversity of microbial communities in underwater environments. In order to provide, e.g., a miniaturized submersible explorer with the capability of collecting microorganisms, a compact sample enrichment system has been developed. The sampler is 30 mm long, 15 mm wide, and just a few millimetres thick. Integrated in a multilayer steel, polyimide and glass construction is a microfluidic channel with piezoelectric transducers, where microorganism and particle samples are collected and enriched, using acoustic radiation forces for gentle and labelless trapping. High-pressure, latchable valves, using paraffin as the actuation material, at each end of the microfluidic channel keep the collected sample pristine. A funnel structure raised above the surface of the device directs water into the microfluidic channel as the vehicle propels itself or when there is a flow across its hull. The valves proved leak proof to a pressure of 2.1 MPa for 19 hours and momentary pressures of 12.5 MPa, corresponding to an ocean depth of more than 1200 metres. By reactivating the latching mechanism, small leakages through the valves could be remedied, which could thus increase the leak-less operational time. Fluorescent particles, 1.9 μm in diameter, were successfully trapped in the microfluidic channel at flow rates up to 15 μl min(-1), corresponding to an 18.5 cm s(-1) external flow rate of the sampler. In addition, liquid-suspended GFP-marked yeast cells were successfully trapped. PMID:22422039

  2. A personal sampler for aircraft engine cold start particles: laboratory development and testing.

    PubMed

    Armendariz, Alfredo; Leith, David

    2003-01-01

    Industrial hygienists in the U.S. Air Force are concerned about exposure of their personnel to jet fuel. One potential source of exposure for flightline ground crews is the plume emitted during the start of aircraft engines in extremely cold weather. The purpose of this study was to investigate a personal sampler, a small tube-and-wire electrostatic precipitator (ESP), for assessing exposure to aircraft engine cold start particles. Tests were performed in the laboratory to characterize the sampler's collection efficiency and to determine the magnitude of adsorption and evaporation artifacts. A low-temperature chamber was developed for the artifact experiments so tests could be performed at temperatures similar to actual field conditions. The ESP collected particles from 0.5 to 20 micro m diameter with greater than 98% efficiency at particle concentrations up to 100 mg/m(3). Adsorption artifacts were less than 5 micro g/m(3) when sampling a high concentration vapor stream. Evaporation artifacts were significantly lower for the ESP than for PVC membrane filters across a range of sampling times and incoming vapor concentrations. These tests indicate that the ESP provides more accurate exposure assessment results than traditional filter-based particle samplers when sampling cold start particles produced by an aircraft engine.

  3. Personal sampler for monitoring of viable viruses; modelling of outdoor sampling conditions

    NASA Astrophysics Data System (ADS)

    Borodulin, A. I.; Desyatkov, B. M.; Lapteva, N. A.; Sergeev, A. N.; Agranovski, I. E.

    A new personal bioaerosol sampler has recently been developed and verified to be very efficient for monitoring of viable airborne bacteria, fungi and viruses. The device is capable of providing high recovery rates even for microorganisms which are rather sensitive to physical and biological stresses. However, some mathematical procedure is required for realistic calculation of an actual concentration of viable bioaerosols in the air taking into account a rate of inactivation of targeted microorganisms, sampling parameters, and results of microbial analysis of collecting liquid from the sampler. In this paper, we develop such procedure along with the model of aerosol propagation for outdoor conditions. Combining these procedures allows one to determine the optimal sampling locations for the best possible coverage of the area to be monitored. A hypothetical episode concerned with terrorists' attack during music concert in the central square of Novosibirsk, Russia was considered to evaluate possible coverage of the area by sampling equipment to detect bioaerosols at various locations within the square. It was found that, for chosen bioaerosol generation parameters and weather conditions, the new personal sampler would be capable to reliably detect pathogens at all locations occupied by crowd, even at distances of up to 600 m from the source.

  4. A personal sampler for aircraft engine cold start particles: laboratory development and testing.

    PubMed

    Armendariz, Alfredo; Leith, David

    2003-01-01

    Industrial hygienists in the U.S. Air Force are concerned about exposure of their personnel to jet fuel. One potential source of exposure for flightline ground crews is the plume emitted during the start of aircraft engines in extremely cold weather. The purpose of this study was to investigate a personal sampler, a small tube-and-wire electrostatic precipitator (ESP), for assessing exposure to aircraft engine cold start particles. Tests were performed in the laboratory to characterize the sampler's collection efficiency and to determine the magnitude of adsorption and evaporation artifacts. A low-temperature chamber was developed for the artifact experiments so tests could be performed at temperatures similar to actual field conditions. The ESP collected particles from 0.5 to 20 micro m diameter with greater than 98% efficiency at particle concentrations up to 100 mg/m(3). Adsorption artifacts were less than 5 micro g/m(3) when sampling a high concentration vapor stream. Evaporation artifacts were significantly lower for the ESP than for PVC membrane filters across a range of sampling times and incoming vapor concentrations. These tests indicate that the ESP provides more accurate exposure assessment results than traditional filter-based particle samplers when sampling cold start particles produced by an aircraft engine. PMID:14674798

  5. Sampling of BTX in Hat Yai city using cost effective laboratory-built PCB passive sampler.

    PubMed

    Subba, Jas Raj; Thammakhet, Chongdee; Thavarungkul, Panote; Kanatharana, Proespichaya

    2016-08-23

    A laboratory-built printed circuit board (PCB) passive sampler used for the monitoring of xylene and styrene in copy print shops was re-validated for detecting benzene, toluene and xylene (BTX) and applied for the sampling of ambient air from Hat Yai city, Songkhla, Thailand, in the month of November 2014. For monitoring, the PCB passive samplers were exposed to target analytes in 16 locations covering high to low exposure areas. After sampling, the samplers were thermally desorbed and the analytes were trapped by multi-walled carbon nanotubes packed into a micro-preconcentrator coupled to a gas chromatograph (GC) equipped with a flame ionization detector. At the optimum GC operating conditions, the linear dynamic ranges for BTX were 0.06-5.6 µg for benzene, 0.07-2.2 µg for toluene and 0.23-2.5 µg for xylene with R(2) > 0.99 with the limits of detection being 6.6, 6.8 and 19 ng for benzene, toluene and xylene, respectively. The concentrations of BTX in the 16 sampling sites were in the range of N.D.-1.3 ± 1.6, 4.50 ± 0.76-49.6 ± 3.7 and 1.00 ± 0.21-39.6 ± 3.1 µg m(-3), respectively. When compared to past studies, there had been an increase in the benzene concentration. PMID:27231039

  6. Laboratory evaluation of the CIP 10 personal dust sampler.

    PubMed

    Gero, A; Tomb, T

    1988-06-01

    The "capteur individuel de poussiere" CIP 10 personal dust sampler--developed by the Centre d'Etudes et Recherches de Charbonnages de France (CERCHAR) research organization--is a small, quiet, lightweight unit which samples at a flow rate of 10 L/min. It is a three-stage sampler, using two stages to remove nonrespirable dust particles and one stage to collect the respirable fraction. Airflow through the sampler is induced by the third stage, which is a rotating collector cup that contains a fine grade sponge. Laboratory tests were conducted in a dust chamber using aerosols of Arizona road dust, coal dust and silica dust. Aerosol concentrations measured with the CIP 10 were compared to those measured with the coal mine dust personal sampler unit used in the United States. The results of this study showed that aerosol concentrations measured with the CIP 10 were linearly related to those obtained with the coal mine dust personal sampler. The relationship, however, was dependent on preselector configuration and aerosol characteristics. The collection medium allows some small particles (less than 3 microns) to pass through the sampler without being collected. As much as 13% (by weight) of the aerosol that penetrated through the preseparating stages was exhausted from the sampler.

  7. Laboratory evaluation of the CIP 10 personal dust sampler.

    PubMed

    Gero, A; Tomb, T

    1988-06-01

    The "capteur individuel de poussiere" CIP 10 personal dust sampler--developed by the Centre d'Etudes et Recherches de Charbonnages de France (CERCHAR) research organization--is a small, quiet, lightweight unit which samples at a flow rate of 10 L/min. It is a three-stage sampler, using two stages to remove nonrespirable dust particles and one stage to collect the respirable fraction. Airflow through the sampler is induced by the third stage, which is a rotating collector cup that contains a fine grade sponge. Laboratory tests were conducted in a dust chamber using aerosols of Arizona road dust, coal dust and silica dust. Aerosol concentrations measured with the CIP 10 were compared to those measured with the coal mine dust personal sampler unit used in the United States. The results of this study showed that aerosol concentrations measured with the CIP 10 were linearly related to those obtained with the coal mine dust personal sampler. The relationship, however, was dependent on preselector configuration and aerosol characteristics. The collection medium allows some small particles (less than 3 microns) to pass through the sampler without being collected. As much as 13% (by weight) of the aerosol that penetrated through the preseparating stages was exhausted from the sampler. PMID:2840817

  8. A new sampler for stratified lagoon chemical and microbiological assessments.

    PubMed

    McLaughlin, M R; Brooks, J P; Adeli, A

    2014-07-01

    A sampler was needed for a spatial and temporal study of microbial and chemical stratification in a large swine manure lagoon that was known to contain zoonotic bacteria. Conventional samplers were limited to collections of surface water samples near the bank or required a manned boat. A new sampler was developed to allow simultaneous collection of multiple samples at different depths, up to 2.3 m, without a manned boat. The sampler was tethered for stability, used remote control (RC) for sample collection, and accommodated rapid replacement of sterile tubing modules and sample containers. The sampler comprised a PVC pontoon with acrylic deck and watertight enclosures, for a 12 VDC gearmotor, to operate the collection module, and vacuum system, to draw samples into reusable autoclavable tubing and 250-mL bottles. Although designed primarily for water samples, the sampler was easily modified to collect sludge. The sampler held a stable position during deployment, created minimal disturbance in the water column, and was readily cleaned and sanitized for transport. The sampler was field tested initially in a shallow fresh water lake and subsequently in a swine manure treatment lagoon. Analyses of water samples from the lagoon tests showed that chemical and bacterial levels, pH, and EC did not differ between 0.04, 0.47, and 1.0 m depths, but some chemical and bacterial levels differed between winter and spring collections. These results demonstrated the utility of the sampler and suggested that future manure lagoon studies employ fewer or different depths and more sampling dates. PMID:24549945

  9. Field and Wind Tunnel Comparison of Four Aerosol Samplers Using Agricultural Dusts

    PubMed Central

    Reynolds, Stephen J.; Nakatsu, Jason; Tillery, Marvin; Keefe, Thomas; Mehaffy, John; Thorne, Peter S.; Donham, Kelley; Nonnenmann, Matthew; Golla, Vijay; O'shaughnessy, Patrick

    2009-01-01

    Occupational lung disease is a significant problem among agricultural workers exposed to organic dusts. Measurements of exposure in agricultural environments in the USA have traditionally been conducted using 37-mm closed-face cassettes (CFCs) and respirable Cyclones. Inhalable aerosol samplers offer significant improvement for dose estimation studies to reduce respiratory disease. The goals of this study were to determine correction factors between the inhalable samplers (IOM and Button) and the CFC and Cyclone for dusts sampled in livestock buildings and to determine whether these factors vary among livestock types. Determination of these correction factors will allow comparison between inhalable measurements and historical measurements. Ten sets of samples were collected in swine, chicken, turkey, and dairy facilities in both Colorado and Iowa. Pairs of each sampling device were attached to the front and back of a rotating mannequin. Laboratory studies using a still-air chamber and a wind tunnel provided information regarding the effect of wind speed on sampler performance. Overall, the IOM had the lowest coefficient of variation (best precision) and was least affected by changes in wind speed. The performance of the Button was negatively impacted in poultry environments where larger (feather) particulates clogged the holes in the initial screen. The CFC/IOM ratios are important for comparisons between newer and older studies. Wind speed and dust type were both important factors affecting ratios. Based on the field studies (Table 6), a ratio of 0.56 is suggested as a conversion factor for the CFC/IOM (average for all environments because of no statistical difference). Suggested conversion factors for the Button/IOM are swine (0.57), chicken (0.80), turkey (0.53), and dairy (0.67). Any attempt to apply a conversion factor between the Cyclone and inhalable samplers is not recommended. PMID:19443852

  10. High efficiency CIP 10-I personal inhalable aerosol sampler

    NASA Astrophysics Data System (ADS)

    Görner, P.; Wrobel, R.; Simon, X.

    2009-02-01

    The CIP 10 personal aerosol sampler was first developed by Courbon for sampling the respirable fraction of mining dust. This respirable aerosol sampler was further improved by Fabries, then selectors for sampling thoracic and inhalable aerosols were designed. Kenny et al. evaluated the particle-size dependent sampling efficiency of the inhalable version in a large-scale wind tunnel using a life-size dummy. The authors found that the overall sampling efficiency decreases more rapidly than the CEN-ISO-ACGIH target efficiency curve. Görner and Witschger measured the aspiration efficiency of the CIP 10 omni-directional inlet. They found that the aspiration efficiency was high enough for inhalable aerosol sampling. This result led to the conclusion that the low sampling efficiency is due to some internal losses of the aspirated particles before they reach the final sampling stage, namely the CIP 10 rotating filter. Based on the assumption that the inhalable particles are selected at selector aspiration level, an experimental research project was conducted to improve particle transmission to the collection stage of the sampler. Two different inhalable selectors were designed by Görner and tested in a laboratory wind tunnel. The transmission efficiency of both models was measured by Roger following an experimental protocol described by Witschger. The T-shaped air flow circuit was finally adopted to draw the aspirated particles into the final collection stage of the CIP 10. Actually, in this selector, the almost horizontally aspirated particles should be conducted vertically to the rotating cup. In two previous prototypes, particles could be deposited in certain places by inertia (where the aerosol was forced to deviate drastically) or by sedimentation (where the aerosol decelerated). The aerodynamic behaviour of the adopted solution causes the particles to accelerate radially between two horizontal plates before they enter a vertical tube. This acceleration avoids the

  11. Testing of high-volume sampler inlets for the sampling of atmospheric radionuclides.

    PubMed

    Irshad, Hammad; Su, Wei-Chung; Cheng, Yung S; Medici, Fausto

    2006-09-01

    Sampling of air for radioactive particles is one of the most important techniques used to determine the nuclear debris from a nuclear weapon test in the Earth's atmosphere or those particles vented from underground or underwater tests. Massive-flow air samplers are used to sample air for any indication of radionuclides that are a signature of nuclear tests. The International Monitoring System of the Comprehensive Nuclear Test Ban Treaty Organization includes seismic, hydroacoustic, infrasound, and gaseous xenon isotopes sampling technologies, in addition to radionuclide sampling, to monitor for any violation of the treaty. Lovelace Respiratory Research Institute has developed a large wind tunnel to test the outdoor radionuclide samplers for the International Monitoring System. The inlets for these samplers are tested for their collection efficiencies for different particle sizes at various wind speeds. This paper describes the results from the testing of two radionuclide sampling units used in the International Monitoring System. The possible areas of depositional wall losses are identified and the losses in these areas are determined. Sampling inlet type 1 was tested at 2.2 m s wind speed for 5, 10, and 20-microm aerodynamic diameter particles. The global collection efficiency was about 87.6% for 10-microm particles for sampling inlet type 1. Sampling inlet type 2 was tested for three wind speeds at 0.56, 2.2, and 6.6 m s for 5, 10, and 20-microm aerodynamic diameter particles in two different configurations (sampling head lowered and raised). The global collection efficiencies for these configurations for 10-microm particles at 2.2 m s wind speed were 77.4% and 82.5%, respectively. The sampling flow rate was 600 m h for both sampling inlets.

  12. Automated particulate sampler field test model operations guide

    SciTech Connect

    Bowyer, S.M.; Miley, H.S.

    1996-10-01

    The Automated Particulate Sampler Field Test Model Operations Guide is a collection of documents which provides a complete picture of the Automated Particulate Sampler (APS) and the Field Test in which it was evaluated. The Pacific Northwest National Laboratory (PNNL) Automated Particulate Sampler was developed for the purpose of radionuclide particulate monitoring for use under the Comprehensive Test Ban Treaty (CTBT). Its design was directed by anticipated requirements of small size, low power consumption, low noise level, fully automatic operation, and most predominantly the sensitivity requirements of the Conference on Disarmament Working Paper 224 (CDWP224). This guide is intended to serve as both a reference document for the APS and to provide detailed instructions on how to operate the sampler. This document provides a complete description of the APS Field Test Model and all the activity related to its evaluation and progression.

  13. 50 CFR 260.47 - Who may become licensed sampler.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE PROCESSED FISHERY PRODUCTS, PROCESSED PRODUCTS THEREOF, AND CERTAIN OTHER PROCESSED FOOD PRODUCTS INSPECTION AND CERTIFICATION Inspection and Certification of Establishments and... of the Department. Licensed samplers shall have no authority to inspect processed products under...

  14. Evaluation of a personal and microenvironmental aerosol speciation sampler (PMASS).

    PubMed

    Geyh, Alison S; Hering, Susanne; Kreisberg, Nathan; John, Walter

    2004-11-01

    In this study, an all-aluminum sampler was reconfigured to a lighter weight by using plastic for structural components not contacted by aerosol. Because the sampler body was made of plastic, the aluminum size-selective cyclone inlet was redesigned into a separate, removable unit. The resulting personal and microenvironmental aerosol speciation sampler (PMASS*) is a small, compact sampler designed for assaying concentrations of each major chemical constituent of particulate matter less than or equal to 2.5 pm in aerodynamic diameter (PM2.5) as well as its mass. The sampler consists of a miniature cyclone inlet and two parallel sampling channels, each of which may accommodate a denuder, particle filter, and backup filter. One channel serves to measure mass and inorganic ions; the other, organic and elemental carbon. Six of these samplers were first evaluated in the laboratory to verify the 50% cutpoint of the redesigned cyclone inlet near the target flow rate of 4.0 L/min and to test the effect of sampler orientation, aerosol type, and flow rate on the 50% cutpoint. The six samplers were fabricated at two different times with slight modifications in construction that yielded slightly different 50% cutpoints. The units were then evaluated as microenvironmental samplers under field conditions against reference samplers in Fresno, California, and Baltimore, Maryland. Testing in Maryland also included deployment as a personal sampler. In the laboratory, the mean (+/- SD) 50% cutpoint at a 4.1 L/min flow rate was 2.52 +/- 0.08 pm. Sampler orientation did not affect performance of the cyclone. Small differences in penetration efficiency were found with different challenge aerosols. For flow rates between 3.1 and 4.9 L/min, the 50% cutpoint varied from 3.3 pm to 2.1 pm, respectively. As a microenvironmental sampler, the PMASS performed well against relevant reference samplers for elemental carbon, organic carbon, and nitrate measurements but not for mass measurements, for

  15. Minanre Gas Concentrators For Air Sampling

    SciTech Connect

    Dr. Seung Ho Hong

    2001-03-01

    The goal of this project was to demonstrate the feasibility of a compact, lightweight, gas-sampling device with rapid-cycle-time characteristics. The highlights of our Phase I work include: (1) Demonstration of a compact gas sampler with integrated heater. This device has an order of magnitude greater adsorption capacity and much faster heating/cooling times than commercial sorbent tubes. (2) Completion of computational fluid dynamics modeling of the gas sampler to determine airflow characteristics for various design options. These modeling efforts guided the development and testing of the Mesochannel Gas Sampler prototype. (3) Testing of the Mesochannel Gas Sampler in parallel with tests of two packed-bed samplers. These tests showed the Mesochannel Gas Sampler represents a substantial improvement compared with the packed-bed approach. Our mesochannel heat-exchanger/adsorber architecture allows very efficient use of adsorbent mass, high adsorbent loadings, and very low pressure drop, which makes possible very high air-sampling rates using a simple, low-power fan. This device is well-suited for collecting samples of trace-level contaminants. The integrated heater, which forms the adsorbent-coated mesochannel walls, allows direct heating of the adsorbent and results in very rapid desorption of the adsorbed species. We believe the Mesochannel Gas Sampler represents a promising technology for the improvement of trace-contaminant detection limits. In our Phase II proposal, we outline several improvements to the gas sampler that will further improve its performance.

  16. The application of performance standards to personal airborne dust samplers.

    PubMed

    Kenny, L C; Lidén, G

    1989-01-01

    This paper summarizes current proposals for the specification and testing of personal sampler performance, and discusses their implications for the precision of dust concentration estimates. A method of specifying the performance of a sampling instrument in terms of the range of masses it would collect from various dust clouds is proposed. Some of the practical difficulties which are likely to arise in the process of testing real samplers with respect to performance standards are discussed.

  17. The development of a test system for investigating the performances of personal aerosol samplers under actual workplace conditions.

    PubMed

    Botham, R A; Hughson, G W; Vincent, J H; Mark, D

    1991-10-01

    The performances of new "total" aerosol samplers for use in workplaces are required to match the inhalability criteria as contained in the latest recommendations of the International Standards Organization (ISO) and the American Conference of Governmental Industrial Hygienists (ACGIH). In the past, practical evaluations have been carried out under idealized conditions in wind tunnels, and there is now the need to extend these to more realistic workplace conditions. This paper describes a new test system that was designed and built for this purpose. It consisted of a life-size mannequin mounted on a trolley so that it can be taken to and wheeled around in workplaces. The mannequin itself incorporated a robotic arm so that, under joystick control, it can be made to simulate a range of worker movements, orientations, and attitudes. An electronically controlled, compact breathing machine provided a range of typical breathing parameters for the mannequin. The pump also provided air movement for a number of personal samplers that were mounted on the torso of the mannequin and tested in that position. Sampler performance should be assessed by comparing directly the aerosol collected by the sampler with that inhaled by the mannequin (and collected on filters inside the head).

  18. A Gibbs sampler for multivariate linear regression

    NASA Astrophysics Data System (ADS)

    Mantz, Adam B.

    2016-04-01

    Kelly described an efficient algorithm, using Gibbs sampling, for performing linear regression in the fairly general case where non-zero measurement errors exist for both the covariates and response variables, where these measurements may be correlated (for the same data point), where the response variable is affected by intrinsic scatter in addition to measurement error, and where the prior distribution of covariates is modelled by a flexible mixture of Gaussians rather than assumed to be uniform. Here, I extend the Kelly algorithm in two ways. First, the procedure is generalized to the case of multiple response variables. Secondly, I describe how to model the prior distribution of covariates using a Dirichlet process, which can be thought of as a Gaussian mixture where the number of mixture components is learned from the data. I present an example of multivariate regression using the extended algorithm, namely fitting scaling relations of the gas mass, temperature, and luminosity of dynamically relaxed galaxy clusters as a function of their mass and redshift. An implementation of the Gibbs sampler in the R language, called LRGS, is provided.

  19. Transient digitizer with displacement current samplers

    DOEpatents

    McEwan, T.E.

    1996-05-21

    A low component count, high speed sample gate, and digitizer architecture using the sample gates is based on use of a signal transmission line, a strobe transmission line and a plurality of sample gates connected to the sample transmission line at a plurality of positions. The sample gates include a strobe pickoff structure near the strobe transmission line which generates a charge displacement current in response to propagation of the strobe signal on the strobe transmission line sufficient to trigger the sample gate. The sample gate comprises a two-diode sampling bridge and is connected to a meandered signal transmission line at one end and to a charge-holding cap at the other. The common cathodes are reverse biased. A voltage step is propagated down the strobe transmission line. As the step propagates past a capacitive pickoff, displacement current i=c(dv/dT), flows into the cathodes, driving the bridge into conduction and thereby charging the charge-holding capacitor to a value related to the signal. A charge amplifier converts the charge on the charge-holding capacitor to an output voltage. The sampler is mounted on a printed circuit board, and the sample transmission line and strobe transmission line comprise coplanar microstrips formed on a surface of the substrate. Also, the strobe pickoff structure may comprise a planar pad adjacent the strobe transmission line on the printed circuit board. 16 figs.

  20. Transient digitizer with displacement current samplers

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A low component count, high speed sample gate, and digitizer architecture using the sample gates is based on use of a signal transmission line, a strobe transmission line and a plurality of sample gates connected to the sample transmission line at a plurality of positions. The sample gates include a strobe pickoff structure near the strobe transmission line which generates a charge displacement current in response to propagation of the strobe signal on the strobe transmission line sufficient to trigger the sample gate. The sample gate comprises a two-diode sampling bridge and is connected to a meandered signal transmission line at one end and to a charge-holding cap at the other. The common cathodes are reverse biased. A voltage step is propagated down the strobe transmission line. As the step propagates past a capacitive pickoff, displacement current i=c(dv/dT), flows into the cathodes, driving the bridge into conduction and thereby charging the charge-holding capacitor to a value related to the signal. A charge amplifier converts the charge on the charge-holding capacitor to an output voltage. The sampler is mounted on a printed circuit board, and the sample transmission line and strobe transmission line comprise coplanar microstrips formed on a surface of the substrate. Also, the strobe pickoff structure may comprise a planar pad adjacent the strobe transmission line on the printed circuit board.

  1. Study of fifteen respirable aerosol samplers used in occupational hygiene.

    PubMed

    Görner, P; Wrobel, R; Micka, V; Skoda, V; Denis, J; Fabriès, J F

    2001-01-01

    European and international standards lay down criteria for the size-selective aerosol sampling in occupational hygiene. Aerosol samplers are supposed to match these target sampling criteria. This study focused on 15 aerosol samplers used to sample the conventional respirable fraction. An aerodynamic particle sizer (APS) method was used to measure the sampling efficiency of the samplers in a low-velocity wind tunnel. Polydisperse coal dust was generated as the test aerosol. The data were fitted by an appropriate mathematical model. For some instruments the results show serious deviations from the conventional target curve, whereas other devices meet the convention quite well. The flow rate of certain cyclone-separator-based instruments was optimized to adjust their sampling efficiency. The mass concentration bias and accuracy of the samplers were calculated for a number of ranges of particle size distributions of aerosols commonly found in industrial workplaces. Finally, the performance of each sampler was evaluated using bias and accuracy maps. Most of these samplers are suitable for sampling the CEN-ISO-ACGIH respirable fraction of aerosols, but several require modification of the flow rate. For real industrial situations, the rough knowledge of the aerosol size distribution can guide the choice of an appropriate sampling technique.

  2. Pesticide monitoring in surface water and groundwater using passive samplers

    NASA Astrophysics Data System (ADS)

    Kodes, V.; Grabic, R.

    2009-04-01

    Passive samplers as screening devices have been used within a czech national water quality monitoring network since 2002 (SPMD and DGT samplers for non polar substances and metals). The passive sampler monitoring of surface water was extended to polar substances, in 2005. Pesticide and pharmaceutical POCIS samplers have been exposed in surface water at 21 locations and analysed for polar pesticides, perfluorinated compounds, personal care products and pharmaceuticals. Pesticide POCIS samplers in groundwater were exposed at 5 locations and analysed for polar pesticides. The following active substances of plant protection products were analyzed in surface water and groundwater using LC/MS/MS: 2,4,5-T, 2,4-D, Acetochlor, Alachlor, Atrazine, Atrazine_desethyl, Azoxystrobin, Bentazone, Bromacil, Bromoxynil, Carbofuran, Clopyralid, Cyanazin, Desmetryn, Diazinon, Dicamba, Dichlobenil, Dichlorprop, Dimethoat, Diuron, Ethofumesate, Fenarimol, Fenhexamid, Fipronil, Fluazifop-p-butyl, Hexazinone, Chlorbromuron, Chlorotoluron, Imazethapyr, Isoproturon, Kresoxim-methyl, Linuron, MCPA, MCPP, Metalaxyl, Metamitron, Methabenzthiazuron, Methamidophos, Methidathion, Metobromuron, Metolachlor, Metoxuron, Metribuzin, Monolinuron, Nicosulfuron, Phorate, Phosalone, Phosphamidon, Prometryn, Propiconazole, Propyzamide, Pyridate, Rimsulfuron, Simazine, Tebuconazole, Terbuthylazine, Terbutryn, Thifensulfuron-methyl, Thiophanate-methyl and Tri-allate. The POCIS samplers performed very well being able to provide better picture than grab samples. The results show that polar pesticides and also perfluorinated compounds, personal care products and pharmaceuticals as well occur in hydrosphere of the Czech republic. Acknowledgment: Authors acknowledge the financial support of grant No. 2B06095 by the Ministry of Education, Youth and Sports.

  3. Does DSM-IV Have Equivalents for the Parental Alienation Syndrome (PAS) Diagnosis?

    ERIC Educational Resources Information Center

    Gardner, Richard A.

    2003-01-01

    Child custody evaluators commonly find themselves confronted with resistance when they attempt to use the term parental alienation syndrome (PAS) in courts of law. The purpose of this article is to elucidate the reasons for the reluctance to use the PAS diagnosis and the applicability of parental alienation, as well as current DSM-IV substitute…

  4. Faux Pas Detection and Intentional Action in Asperger Syndrome. A Replication on a French Sample

    ERIC Educational Resources Information Center

    Zalla, Tiziana; Sav, Anca-Maria; Stopin, Astrid; Ahade, Sabrina; Leboyer, Marion

    2009-01-01

    In the present study, we investigated mindreading abilities in a group of adults with Asperger Syndrome (AS) by using the faux pas task, an advanced test of theory of mind (Baron-Cohen et al. (1999). "Journal of Autism and Developmental Disorders, 29," 407-418). The faux pas is a particular case of a non-intentional action reflecting an…

  5. Comparison of using polyurethane foam passive samplers and tree bark samples from Western China to determine atmospheric organochlorine pesticide.

    PubMed

    Li, Qiuxu; Lu, Yao; Jin, Jun; Li, Guangyao; Li, Peng; He, Chang; Wang, Ying

    2016-03-01

    Polyurethane foam (PUF) passive samplers were deployed and tree bark samples were collected at 15 sites across western China in 2013, and the organochlorine pesticide (OCP) concentrations in the samples were determined. Dichlorodiphenyltrichloroethane and its degradation products (collectively called DDTs), hexachlorocyclohexanes (HCHs), and hexachlorobenzene (HCB) were the dominant OCPs in the PUF samples and tree bark samples. The mean DDTs, HCHs and HCB concentrations were 33, 22 and 18ng/sample in the PUF samples, and 428, 74, and 43ng/(g lipid weight (lw)) in the tree bark, respectively. The OCP concentrations in the air, calculated using PUF-air and tree-bark-air partitioning models, were of the same order of magnitude. Both sample types showed that relatively fresh inputs of DDT and HCHs to the environment have occurred in western China. Meanwhile, PUF passive samplers were compared with the use of tree bark samples as passive samplers. The OCP compositions in the PUF and tree bark samples were different. Only the relatively stable OCPs (such as HCB, β-HCH and p,p'-dichlorodiphenyldichloro-ethylene (DDE)) were consistent in the PUF and tree bark samples. PMID:26969054

  6. Postural Assessment Software (PAS/SAPO): Validation and Reliabiliy

    PubMed Central

    Ferreira, Elizabeth Alves G.; Duarte, Marcos; Maldonado, Edison Puig; Burke, Thomaz Nogueira; Marques, Amelia Pasqual

    2010-01-01

    OBJECTIVE: This study was designed to estimate the accuracy of the postural assessment software (PAS/SAPO) for measurement of corporal angles and distances as well as the inter- and intra-rater reliabilities. INTRODUCTION: Postural assessment software was developed as a subsidiary tool for postural assessment. It is easy to use and available in the public domain. Nonetheless, validation studies are lacking. METHODS: The study sample consisted of 88 pictures from 22 subjects, and each subject was assessed twice (1 week interval) by 5 blinded raters. Inter- and intra-rater reliabilities were estimated using the intraclass correlation coefficient. To estimate the accuracy of the software, an inanimate object was marked with hallmarks using pre-established parameters. Pictures of the object were rated, and values were checked against the known parameters. RESULTS: Inter-rater reliability was excellent for 41% of the variables and very good for 35%. Ten percent of the variables had acceptable reliability, and 14% were defined as non-acceptable. For intra-rater reliability, 44.8% of the measurements were considered to be excellent, 23.5% were very good, 12.4% were acceptable and 19.3% were considered non-acceptable. Angular measurements had a mean error analisys of 0.11°, and the mean error analisys for distance was 1.8 mm. DISCUSSION: Unacceptable intraclass correlation coefficient values typically used the vertical line as a reference, and this may have increased the inaccuracy of the estimates. Increased accuracies were obtained by younger raters with more sophisticated computer skills, suggesting that past experience influenced results. CONCLUSION: The postural assessment software was accurate for measuring corporal angles and distances and should be considered as a reliable tool for postural assessment. PMID:20668624

  7. J-PAS data management pipeline and archiving

    NASA Astrophysics Data System (ADS)

    Cristóbal-Hornillos, D.; Gruel, N.; Varela, J.; López-Sainz, A.; Ederoclite, A.; Moles, M.; Cenarro, A. J.; Marín-Franch, A.; Hernández-Fuertes, J.; Yanes-Díaz, A.; Chueca, S.; Rueda-Teruel, S.; Rueda-Teruel, F.; Luis-Simoes, R.

    2012-09-01

    J-PAS survey is going to observe 8000 deg2 in 54 optical narrow band filters plus 3 broad band ones. The survey will produce 1.2 PB of raw data in six years of observations. The treatment of about 1.5 TB per night, coming from the 14 detectors of the JPCam camera in the JST/T250, plus one detector in the JAST/T80 camera, shall be performed during the day after the operations. This contribution presents the software and hardware architecture designed to process and validate the data. The processing of the images is divided in two main stages. The first one, which deals with instrumental correction and data validation, is run daily. The second stage is run when a tile is completed and do the combination of the individual corrected frames and weight maps. To perform the astrometric calibration, image coadding and source extraction the data management pipeline uses software from the community which is integrated through Python. The software uses a database to control the process by storing the operations performed, parameters used and quality checks. This allows fast reprocessing to retrieve intermediate stages of the treatment from the raw data for any data release. This approach saves disk space by avoiding the storage of the processed individual frames. The data archiving and processing will be done in a data center 30 km away from the observatory. It will be equipped with ~2.5 PB of storage capacity to store the raw data and the final mosaics of the 57 filters, and processing power to deal with the incoming data.

  8. Role of the PAS1 gene of Pichia pastoris in peroxisome biogenesis

    PubMed Central

    1994-01-01

    Several groups have reported the cloning and sequencing of genes involved in the biogenesis of yeast peroxisomes. Yeast strains bearing mutations in these genes are unable to grow on carbon sources whose metabolism requires peroxisomes, and these strains lack morphologically normal peroxisomes. We report the cloning of Pichia pastoris PAS1, the homologue (based on a high level of protein sequence similarity) of the Saccharomyces cerevisiae PAS1. We also describe the creation and characterization of P. pastoris pas1 strains. Electron microscopy on the P. pastoris pas1 cells revealed that they lack morphologically normal peroxisomes, and instead contain membrane-bound structures that appear to be small, mutant peroxisomes, or "peroxisome ghosts." These "ghosts" proliferated in response to induction on peroxisome-requiring carbon sources (oleic acid and methanol), and they were distributed to daughter cells. Biochemical analysis of cell lysates revealed that peroxisomal proteins are induced normally in pas1 cells. Peroxisome ghosts from pas1 cells were purified on sucrose gradients, and biochemical analysis showed that these ghosts, while lacking several peroxisomal proteins, did import varying amounts of several other peroxisomal proteins. The existence of detectable peroxisome ghosts in P. pastoris pas1 cells, and their ability to import some proteins, stands in contrast with the results reported by Erdmann et al. (1991) for the S. cerevisiae pas1 mutant, in which they were unable to detect peroxisome-like structures. We discuss the role of PAS1 in peroxisome biogenesis in light of the new information regarding peroxisome ghosts in pas1 cells. PMID:7962088

  9. Deep-Sea Hydrothermal-Vent Sampler

    NASA Technical Reports Server (NTRS)

    Behar, Alberto E.; Venkateswaran, Kasthur; Matthews, Jaret B.

    2008-01-01

    An apparatus is being developed for sampling water for signs of microbial life in an ocean hydrothermal vent at a depth of as much as 6.5 km. Heretofore, evidence of microbial life in deep-sea hydrothermal vents has been elusive and difficult to validate. Because of the extreme conditions in these environments (high pressures and temperatures often in excess of 300 C), deep-sea hydrothermal- vent samplers must be robust. Because of the presumed low density of biomass of these environments, samplers must be capable of collecting water samples of significant volume. It is also essential to prevent contamination of samples by microbes entrained from surrounding waters. Prior to the development of the present apparatus, no sampling device was capable of satisfying these requirements. The apparatus (see figure) includes an intake equipped with a temperature probe, plus several other temperature probes located away from the intake. The readings from the temperature probes are utilized in conjunction with readings from flowmeters to determine the position of the intake relative to the hydrothermal plume and, thereby, to position the intake to sample directly from the plume. Because it is necessary to collect large samples of water in order to obtain sufficient microbial biomass but it is not practical to retain all the water from the samples, four filter arrays are used to concentrate the microbial biomass (which is assumed to consist of particles larger than 0.2 m) into smaller volumes. The apparatus can collect multiple samples per dive and is designed to process a total volume of 10 L of vent fluid, of which most passes through the filters, leaving a total possibly-microbe-containing sample volume of 200 mL remaining in filters. A rigid titanium nose at the intake is used for cooling the sample water before it enters a flexible inlet hose connected to a pump. As the water passes through the titanium nose, it must be cooled to a temperature that is above a mineral

  10. Size-separated sampling and analysis of isocyanates in workplace aerosols. Part I. Denuder--cascade impactor sampler.

    PubMed

    Dahlin, Jakob; Spanne, Mårten; Karlsson, Daniel; Dalene, Marianne; Skarping, Gunnar

    2008-07-01

    Isocyanates in the workplace atmosphere are typically present both in gas and particle phase. The health effects of exposure to isocyanates in gas phase and different particle size fractions are likely to be different due to their ability to reach different parts in the respiratory system. To reveal more details regarding the exposure to isocyanate aerosols, a denuder-impactor (DI) sampler for airborne isocyanates was designed. The sampler consists of a channel-plate denuder for collection of gaseous isocyanates, in series with three-cascade impactor stages with cut-off diameters (d(50)) of 2.5, 1.0 and 0.5 mum. An end filter was connected in series after the impactor for collection of particles smaller than 0.5 mum. The denuder, impactor plates and the end filter were impregnated with a mixture of di-n-butylamine (DBA) and acetic acid for derivatization of the isocyanates. During sampling, the reagent on the impactor plates and the end filter is continuously refreshed, due to the DBA release from the impregnated denuder plates. This secures efficient derivatization of all isocyanate particles. The airflow through the sampler was 5 l min(-1). After sampling, the samples containing the different size fractions were analyzed using liquid chromatography-mass spectrometry (LC-MS)/MS. The DBA impregnation was stable in the sampler for at least 1 week. After sampling, the DBA derivatives were stable for at least 3 weeks. Air sampling was performed in a test chamber (300 l). Isocyanate aerosols studied were thermal degradation products of different polyurethane polymers, spraying of isocyanate coating compounds and pure gas-phase isocyanates. Sampling with impinger flasks, containing DBA in toluene, with a glass fiber filter in series was used as a reference method. The DI sampler showed good compliance with the reference method, regarding total air levels. For the different aerosols studied, vast differences were revealed in the distribution of isocyanate in gas and

  11. Measurements of environmental 1,3-butadiene with pumped and diffusive samplers using the sorbent Carbopack X

    NASA Astrophysics Data System (ADS)

    Martin, Nicholas A.; Duckworth, Philippa; Henderson, Malcolm H.; Swann, Nigel R. W.; Granshaw, Simon T.; Lipscombe, Robert P.; Goody, Brian A.

    Studies with the sorbent Carbopack X in pumped and diffusive samplers, of the Perkin-Elmer-type, have been carried out using a controlled atmosphere test facility (CATFAC) to generate 1,3-butadiene, together with benzene, at environmental levels. The 7-day and 14-day 1,3-butadiene diffusive uptake rates for this sorbent have been determined to be respectively (1.24±0.16) ng ppm -1 min -1 ((0.55±0.07) cm 3 min -1)) and (1.02±0.12) ng ppm -1 min -1 ((0.45±0.05) cm 3 min -1)) under a wide range of concentrations at 20 °C, 50% relative humidity and a wind speed of 1 m s -1. Preliminary studies indicate that this sorbent may also be useful in radial diffusive samplers for short-term monitoring over a few hours. A pumped sampling method has been developed to measure both 1,3-butadiene and benzene simultaneously over a period of 14-days using two Perkin-Elmer-type devices coupled to an in-house developed controlled flow air sampler. The 1,3-butadiene safe sampling volume for Carbopack X has been measured yielding a value of ⩽82 litre g -1. Tests carried out with calibrated amounts of 1,3-butadiene (50 ng and 150 ng) on Carbopack X indicate that samplers should be stored in a refrigerator prior to thermal desorption in order to achieve a recovery of effectively 100%. Ambient ozone does not appear to react with 1,3-butadiene adsorbed in the samplers.

  12. The Abandoned E-Waste Recycling Site Continued to Act As a Significant Source of Polychlorinated Biphenyls: An in Situ Assessment Using Fugacity Samplers.

    PubMed

    Wang, Yan; Luo, Chunling; Wang, Shaorui; Cheng, Zhineng; Li, Jun; Zhang, Gan

    2016-08-16

    The recycling of e-waste has attracted significant attention due to emissions of polychlorinated biphenyls (PCBs) and other contaminants into the environment. We measured PCB concentrations in surface soils, air equilibrated with the soil, and air at 1.5-m height using a fugacity sampler in an abandoned electronic waste (e-waste) recycling site in South China. The total concentrations of PCBs in the soils were 39.8-940 ng/g, whereas the concentrations in air equilibrated with the soil and air at 1.5 m height were 487-8280 pg/m(3) and 287-7380 pg/m(3), respectively. The PCB concentrations displayed seasonal variation; they were higher in winter in the soils and higher in summer in the air, indicating that the emission of PCBs from the soil was enhanced during hot seasons for the relatively high temperature or additional sources, especially for low-chlorinated PCBs. We compared two methods (traditional fugacity model and fugacity sampler) for assessing the soil-air partition coefficients (Ksa) and the fugacity fractions of PCBs. The results suggested that the fugacity sampler provided more instructive and practical estimation on Ksa values and trends in air-soil exchange, especially for low-chlorinated PCBs. The abandoned e-waste burning site still acted as a significant source of PCBs many years after the prohibition on open burning. PMID:27427439

  13. Calibration of the Ogawa passive ozone sampler for aircraft cabins

    NASA Astrophysics Data System (ADS)

    Bhangar, Seema; Singer, Brett C.; Nazaroff, William W.

    2013-02-01

    Elevated ozone levels in aircraft cabins would pose a health hazard to exposed passengers and crew. The Ogawa passive sampler is a potentially useful tool for measuring in-cabin ozone levels. Accurate interpretation of measured values requires knowing the effective collection rate of the sampler. To calibrate the passive sampler for the aircraft-cabin environment, ozone was measured simultaneously with an Ogawa sampler and an active ozone analyzer that served as a transfer standard, on 11 commercial passenger flights, during Feb-Apr 2007. An empirical pressure-independent effective collection rate that can be used to convert nitrate mass to ozone mixing ratio was determined to be 14.3 ± 0.9 atm cm3 min-1 (mean ± standard error). This value is similar to estimates from other applications where airflow rates are low, such as in personal monitoring and in chamber studies. This study represents the first field calibration of any passive sampler for the aircraft cabin environment.

  14. Efficiency of Airborne Sample Analysis Platform (ASAP) bioaerosol sampler for pathogen detection

    PubMed Central

    Sharma, Anurag; Clark, Elizabeth; McGlothlin, James D.; Mittal, Suresh K.

    2015-01-01

    The threat of bioterrorism and pandemics has highlighted the urgency for rapid and reliable bioaerosol detection in different environments. Safeguarding against such threats requires continuous sampling of the ambient air for pathogen detection. In this study we investigated the efficacy of the Airborne Sample Analysis Platform (ASAP) 2800 bioaerosol sampler to collect representative samples of air and identify specific viruses suspended as bioaerosols. To test this concept, we aerosolized an innocuous replication-defective bovine adenovirus serotype 3 (BAdV3) in a controlled laboratory environment. The ASAP efficiently trapped the surrogate virus at 5 × 103 plaque-forming units (p.f.u.) [2 × 105 genome copy equivalent] concentrations or more resulting in the successful detection of the virus using quantitative PCR. These results support the further development of ASAP for bioaerosol pathogen detection. PMID:26074900

  15. Spatial distribution of the persistent organic pollutants across the Tibetan Plateau and its linkage with the climate systems: a 5-year air monitoring study

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoping; Ren, Jiao; Gong, Ping; Wang, Chuanfei; Xue, Yonggang; Yao, Tandong; Lohmann, Rainer

    2016-06-01

    The Tibetan Plateau (TP) has been contaminated by persistent organic pollutants (POPs), including legacy organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) through atmospheric transport. The exact source regions, transport pathways and time trends of POPs to the TP are not well understood. Here polystyrene-divinylbenzene copolymer resin (XAD)-based passive air samplers (PASs) were deployed at 16 Tibetan background sites from 2007 to 2012 to gain further insight into spatial patterns and temporal trends of OCPs and PCBs. The southeastern TP was characterized by dichlorodiphenyltrichloroethane (DDT)-related chemicals delivered by Indian monsoon air masses. The northern and northwestern TP displayed the greatest absolute concentration and relative abundance of hexachlorobenzene (HCB) in the atmosphere, caused by the westerly-driven European air masses. The interactions between the DDT polluted Indian monsoon air and the clean westerly winds formed a transition zone in central Tibet, where both DDT and HCB were the dominant chemicals. Based on 5 years of continuous sampling, our data indicated declining concentrations of HCB and hexachlorocyclohexanes (HCHs) across the Tibetan region. Inter-annual trends of DDT class chemicals, however, showed less variation during this 5-year sampling period, which may be due to the ongoing usage of DDT in India. This paper demonstrates the possibility of using POP fingerprints to investigate the climate interactions and the validity of using PAS to derive inter-annual atmospheric POP time trends.

  16. Evaluation of Slit Sampler in Quantitative Studies of Bacterial Aerosols

    PubMed Central

    Ehrlich, Richard; Miller, Sol; Idoine, L. S.

    1966-01-01

    Quantitative studies were conducted to evaluate the efficiency of the slit sampler in collecting airborne Serratia marcescens and Bacillus subtilis var. niger, and to compare it with the collecting efficiency of the all-glass impinger AGI-30. The slit sampler was approximately 50% less efficient than the AGI-30. This ratio remained the same whether liquid or dry cultures were disseminated when the sample was taken at 2 min of aerosol cloud life. At 30 min of aerosol cloud life, this ratio was approximately 30% for B. subtilis var. niger. S. marcescens recoveries by the slit sampler were, however, only 17% lower than the AGI-30 at 30 min of cloud age, indicating a possible interaction involving the more labile vegetative cells, aerosol age, and method of collection. PMID:4961550

  17. Thickness and material selection of polymeric passive samplers for polycyclic aromatic hydrocarbons in water: Which more strongly affects sampler properties?

    PubMed

    Belles, Angel; Alary, Claire; Mamindy-Pajany, Yannick

    2016-07-01

    Three configurations of single-phase polymer passive samplers made of polyoxymethylene (POM), silicone rubber, and polyethylene (PE) were simultaneously calibrated in laboratory experiments by determining their partitioning coefficients and the POM diffusion coefficients and by validating a kinetic accumulation model. In addition, the performance of each device was evaluated under field conditions. With the support of the developed model, the device properties are discussed with regard to material selection and polymer thickness. The results show that a sampler's properties, such as its concentration-averaging period and ability to sample a large amount of polycyclic aromatic hydrocarbons, are widely affected by material selection. Sampler thickness also allows modulation of the properties of the device but with a much lower magnitude. Selection of the appropriate polymer and/or thickness allows samplers to be adapted either for quick equilibration or for the kinetic accumulation regime and promotes either membrane or water boundary layer control of the kinetic accumulation. In addition, membrane-controlled or equilibrated compounds are quantified with greater accuracy because they are not corrected by the performance reference compounds approach. However, the averaged concentrations cannot be assessed when compounds reach equilibrium in the sampler, whereas membrane-controlled devices remaining in the kinetic accumulation regime provide averaged concentrations without requiring performance reference compound correction; detection limits are then increased because of the higher mass transfer resistance of the membrane. Environ Toxicol Chem 2016;35:1708-1717. © 2015 SETAC. PMID:26647116

  18. Validation of Ogawa passive samplers for the determination of gaseous ammonia concentrations in agricultural settings

    NASA Astrophysics Data System (ADS)

    Roadman, M. J.; Scudlark, J. R.; Meisinger, J. J.; Ullman, W. J.

    The Ogawa passive sampler (Ogawa USA, Pompano Beach, Florida) is a useful tool for monitoring atmospheric ammonia (NH 3(g)) concentrations and assessing the effects of agricultural waste management practices on NH 3(g) emissions. The Ogawa sampler, with filter-discs impregnated with citric acid, was used to trap and determine NH 3(g) concentrations in a variety of agricultural settings. A wide range of NH 3(g) concentrations can be monitored by varying the sampler exposure time, provided that no more than ˜10 μg of NH 3-N are adsorbed on the acid-coated filters. Concentrations less than 1 μg NH 3-N m -3 can be detected using long deployments (⩽14 days), while concentrations as great as 10 mg NH 3-N m -3 may be determined in very short (e.g. 5 min) deployments. Reproducibility ranged from 5% to 10% over the range of concentrations studied and passive determinations of NH 3(g) were similar to those determined using dilute-acid gas scrubbers. Background levels of NH 3(g) at a non-agricultural site in southern Delaware were typically <1 μg NH 3-N m -3. The air entering a chicken house was 10 μg NH 3-N m -3, reflecting the background levels in agricultural settings in this region. Within the house, concentrations ⩽8.5 mg NH 3-N m -3 were observed, reflecting the high rates of NH 3(g) emission from chicken excreta. Using measured NH 3(g) concentrations and poultry house ventilation rates, we estimate that each broiler grown to production size over 6 weeks contributes approximately 19±3 g of NH 3-N to the atmosphere, a value consistent with other published results.

  19. Electrostatic particle sampler and chemical sensor system for land mine detection by chemical signature

    NASA Astrophysics Data System (ADS)

    Fisher, Mike; Cumming, Colin J.; la Grone, Marcus J.; Taylor, Robert

    1998-09-01

    Locating landmines and UXO by detection of the chemical signature emanating from these devices is extremely challenging due to several of the physical properties of explosives. Because the explosives used in landmines and UXO have extremely low vapor pressures, the concentration of explosive vapors escaping from the ordnance is very low. Fate and transport studies of explosives in soil over buried ordnance have indicated that once released into the soil, virtually all of the explosive vapor is quickly adsorbed onto the surface of soil particles. This behavior is not surprising, since explosives are known to readily adsorb onto most types of surfaces. The adsorption of explosive onto soil particles is to an extent a reversible process, enabling diffusion of explosive through the soil. Unfortunately, because of irreversible adsorption and other processes occurring in the soil that destroy or degrade the explosive, the concentration of explosive reaching the surface of the ground is extremely low. However, dogs are able to locate buried ordnance, indicating that explosive signature compounds are present at or near the surface of the ground at concentrations in excess of the minimum detection limit of canines. Since the fate and transport studies indicate a much higher concentration of explosive adsorbed onto soil particles than in the vapor phase, sampling the explosive adsorbed onto soil particles may be a more efficient approach to sampling explosives than sampling explosive vapor in the air over buried ordnance. An electrostatic particle sampler has been designed which is capable of rapidly and efficiently sampling soil particles. Once the soil particles have been sampled, the explosive is desorbed from the particles, concentrated, and then presented to a sensitive chemical detector for analysis. In its present configuration, the particle sampler delivers a vapor phase sample to the detector, but the device could be adapted to deliver samples in the solvent phase

  20. Third Annual Maintenance Inspection & Test Report for PAS-1 Cask Certification for Shipping Payload B

    SciTech Connect

    KELLY, D.L.

    2001-11-01

    This, Third Annual Maintenance, Inspection, and Test Report for PAS-1 Cask Certification for Shipping Payload B, documents the successful completion of maintenance, testing, and inspections for two casks, serial numbers 2161-026 and 2162-027.

  1. A population-based exposure assessment methodology for carbon monoxide: Development of a carbon monoxide passive sampler and occupational dosimeter

    SciTech Connect

    Apte, M.G.

    1997-09-01

    Two devices, an occupational carbon monoxide (CO) dosimeter (LOCD), and an indoor air quality (IAQ) passive sampler were developed for use in population-based CO exposure assessment studies. CO exposure is a serious public health problem in the U.S., causing both morbidity and mortality (lifetime mortality risk approximately 10{sup -4}). Sparse data from population-based CO exposure assessments indicate that approximately 10% of the U.S. population is exposed to CO above the national ambient air quality standard. No CO exposure measurement technology is presently available for affordable population-based CO exposure assessment studies. The LOCD and IAQ Passive Sampler were tested in the laboratory and field. The palladium-molybdenum based CO sensor was designed into a compact diffusion tube sampler that can be worn. Time-weighted-average (TWA) CO exposure of the device is quantified by a simple spectrophotometric measurement. The LOCD and IAQ Passive Sampler were tested over an exposure range of 40 to 700 ppm-hours and 200 to 4200 ppm-hours, respectively. Both devices were capable of measuring precisely (relative standard deviation <20%), with low bias (<10%). The LOCD was screened for interferences by temperature, humidity, and organic and inorganic gases. Temperature effects were small in the range of 10{degrees}C to 30{degrees}C. Humidity effects were low between 20% and 90% RH. Ethylene (200 ppm) caused a positive interference and nitric oxide (50 ppm) caused a negative response without the presence of CO but not with CO.

  2. Changes in quaternary structure in the signaling mechanisms of PAS domains.

    PubMed

    Ayers, Rebecca A; Moffat, Keith

    2008-11-18

    FixL from Bradyrhizobium japonicum is a PAS sensor protein in which two PAS domains covalently linked to a histidine kinase domain are responsible for regulating nitrogen fixation in an oxygen-dependent manner. The more C-terminal PAS domain, denoted bjFixLH, contains a heme cofactor that binds diatomic molecules such as carbon monoxide and oxygen and regulates the activity of the FixL histidine kinase as part of a two-component signaling system. We present the structures of ferric, deoxy, and carbon monoxide-bound bjFixLH in a new space group ( P1) and at resolutions (1.5-1.8 A) higher than the resolutions of those previously obtained. Interestingly, bjFixLH can form two different dimers (in P1 and R32 crystal forms) in the same crystallization solution, where the monomers in one dimer are rotated approximately 175 degrees relative to the second. This suggests that PAS monomers are plastic and that two quite distinct quaternary structures are closely similar in free energy. We use screw rotation analysis to carry out a quantitative pairwise comparison of PAS quaternary structures, which identifies five different relative orientations adopted by isolated PAS monomers. We conclude that PAS monomer arrangement is context-dependent and could differ depending on whether the PAS domains are isolated or are part of a full-length protein. Structurally homologous residues comprise a conserved dimer interface. Using network analysis, we find that the architecture of the PAS dimer interface is continuous rather than modular; the network of residues comprising the interface is strongly connected. A continuous dimer interface is consistent with the low dimer-monomer dissociation equilibrium constant. Finally, we quantitate quaternary structural changes induced by carbon monoxide binding to a bjFixLH dimer, in which monomers rotate by up to approximately 2 degrees relative to each other. We relate these changes to those in other dimeric PAS domains and discuss the role of

  3. Changes in Quaternary Structure in the Signaling Mechanisms of PAS Domains

    SciTech Connect

    Ayers, Rebecca A.; Moffat, Keith

    2008-12-15

    FixL from Bradyrhizobium japonicum is a PAS sensor protein in which two PAS domains covalently linked to a histidine kinase domain are responsible for regulating nitrogen fixation in an oxygen-dependent manner. The more C-terminal PAS domain, denoted bjFixLH, contains a heme cofactor that binds diatomic molecules such as carbon monoxide and oxygen and regulates the activity of the FixL histidine kinase as part of a two-component signaling system. We present the structures of ferric, deoxy, and carbon monoxide-bound bjFixLH in a new space group (P1) and at resolutions (1.5--1.8 {angstrom}) higher than the resolutions of those previously obtained. Interestingly, bjFixLH can form two different dimers (in P1 and R32 crystal forms) in the same crystallization solution, where the monomers in one dimer are rotated {approx}175 deg. relative to the second. This suggests that PAS monomers are plastic and that two quite distinct quaternary structures are closely similar in free energy. We use screw rotation analysis to carry out a quantitative pairwise comparison of PAS quaternary structures, which identifies five different relative orientations adopted by isolated PAS monomers. We conclude that PAS monomer arrangement is context-dependent and could differ depending on whether the PAS domains are isolated or are part of a full-length protein. Structurally homologous residues comprise a conserved dimer interface. Using network analysis, we find that the architecture of the PAS dimer interface is continuous rather than modular; the network of residues comprising the interface is strongly connected. A continuous dimer interface is consistent with the low dimer-monomer dissociation equilibrium constant. Finally, we quantitate quaternary structural changes induced by carbon monoxide binding to a bjFixLH dimer, in which monomers rotate by up to 2 deg. relative to each other. We relate these changes to those in other dimeric PAS domains and discuss the role of quaternary structural

  4. PAS-cal: a Generic Recombinant Peptide Calibration Standard for Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Breibeck, Joscha; Serafin, Adam; Reichert, Andreas; Maier, Stefan; Küster, Bernhard; Skerra, Arne

    2014-08-01

    We describe the design, preparation, and mass-spectrometric characterization of a new recombinant peptide calibration standard with uniform biophysical and ionization characteristics for mass spectrometry. "PAS-cal" is an artificial polypeptide concatamer of peptide cassettes with varying lengths, each composed of the three small, chemically stable amino acids Pro, Ala, and Ser, which are interspersed by Arg residues to allow site-specific cleavage with trypsin. PAS-cal is expressed at high yields in Escherichia coli as a Small Ubiquitin-like MOdifier (SUMO) fusion protein, which is easily purified and allows isolation of the PAS-cal moiety after SUMO protease cleavage. Upon subsequent in situ treatment with trypsin, the PAS-cal polypeptide yields a set of four defined homogeneous peptides in the range from 2 to 8 kDa with equal mass spacing. ESI-MS analysis revealed a conveniently interpretable raw spectrum, which after deconvolution resulted in a very simple pattern of four peaks with similar ionization signals. MALDI-MS analysis of a PAS-cal peptide mixture comprising both the intact polypeptide and its tryptic fragments revealed not only the four standard peptides but also the singly and doubly charged states of the intact concatamer as well as di- and trimeric adduct ion species between the peptides, thus augmenting the observable m/z range. The advantageous properties of PAS-cal are most likely a result of the strongly hydrophilic and conformationally disordered PEG-like properties of the PAS sequences. Therefore, PAS-cal offers an inexpensive and versatile recombinant peptide calibration standard for mass spectrometry in protein/peptide bioanalytics and proteomics research, the composition of which may be further adapted to fit individual needs.

  5. HID-AB2.5-PAS and HID-PAS methods for the histochemical analyses of a variety of carbohydrates.

    PubMed

    Ueda, T; Mittal, A K; Fujimori, O; Yamada, K

    1994-05-01

    The high iron diamine (HID) staining procedure was combined with alcian blue pH 2.5 (AB2.5) and periodic acid-Schiff (PAS) methods for the simultaneous demonstration of carbohydrates containing sulfate esters, carboxyl groups and oxidizable vicinal diols, whereas it was sequentially employed with PAS alone to differentiate sulfate esters from oxidizable vicinal diols. A variety of rat tissues and the epidermis of four fish species were utilized to test the specificity or selectivity of these methods. The HID-AB2.5-PAS sequence largely coloured carbohydrates containing sulfate esters, carboxyl groups and oxidizable vicinal diols in brownish black, turquoise and magenta shades respectively. The HID-PAS sequence coloured sulfate esters brownish black and oxidizable vicinal diols magenta. On the basis of the experimental and control studies on the both staining techniques, these staining methods could be postulated to represent efficient and useful techniques for precise histochemical analyses and simultaneous differentiations of a variety of carbohydrates in light microscopy.

  6. Evaluating the Relationship between Equilibrium Passive Sampler Uptake and Aquatic Organism Bioaccumulation

    EPA Science Inventory

    This Critcal Review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Fifty-seven studies were found where both passive sampler uptake and organism bioaccumulat...

  7. Selecting Performance Reference Compounds (PRCS) for Low Density Polyethylene Passive Samplers

    EPA Science Inventory

    Use of equilibrium passive samplers for performing aquatic environmental monitoring at contaminated sites is becoming more common. However, a current challenge in passive sampling is determining when equilibrium is achieved between the sampler, target contaminants, and environm...

  8. Determining Passive Sampler Partition Coefficients for Dissolved-phase Organic Contaminants

    EPA Science Inventory

    Passive samplers are used for environmental and analytical purposes to measure dissolved nonionic organic contaminants (NOCs) by absorption from a contaminated medium into a clean phase, usually in the form of a synthetic organic film. Recently developed passive sampler techniqu...

  9. The influence of geometry and draught shields on the performance of passive samplers.

    PubMed

    Hofschreuder, P; van der Meulen, W; Heeres, P; Slanina, S

    1999-04-01

    Passive samplers provide an excellent opportunity to perform indicative measurements or establish a dense network of measuring sites. A drawback compared with conventional active measuring methods is the larger spread of results. This variation can, to a large extent, be attributed to the influence of temperature, sampler geometry and wind on sampling results. A proper design of sampler geometry and optimum choice of draught shield can reduce the influence of wind velocity on a badge type sampler to less than 10%. Wire mesh screens prove to be inadequate in damping turbulence. Filters give good results. Attention should be paid to the size and isolation value of the walls of the sampler to prevent thermal updrafts occurring within the sampler. Tube type samplers are less influenced by wind, provided that turbulence is prevented from influencing diffusion within the sampler.

  10. Enhanced surface sampler and process for collection and release of analytes

    DOEpatents

    Addleman, Raymond S; Atkinson, David A; Bays, John T; Chouyyok, Wilaiwan; Cinson, Anthony D; Ewing, Robert G; Gerasimenko, Aleksandr A

    2015-02-03

    An enhanced swipe sampler and method of making are described. The swipe sampler is made of a fabric containing selected glass, metal oxide, and/or oxide-coated glass or metal fibers. Fibers are modified with silane ligands that are directly attached to the surface of the fibers to functionalize the sampling surface of the fabric. The swipe sampler collects various target analytes including explosives and other threat agents on the surface of the sampler.

  11. Development of a portable membrane contactor sampler for noble gas analyses of surface and groundwater samples

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.; Han, L. H.; Jaklitsh, M.; Aggarwal, P. K.

    2012-04-01

    Noble gas isotopes dissolved in groundwater provide valuable information about climatic conditions during air-water exchange, as well as the residence time of groundwater and its renewal rate. The isotope composition of noble gases can also serve as geochemical fingerprints to decipher the origin of groundwater and its flow system. Conventionally, groundwater is sampled using a copper tube, which is subsequently degassed using a vacuum extraction system for isotope analysis by a mass spectrometer. Although this conventional and well-established way of sampling is widely recognised as being reliable and robust, a major drawback to this method is its size and weight. For example, our sampler consists of a copper tube of 10 mm diameter x 1000 mm length and a metal casing with pinch-off clamps with its total weight to be 2 kg each. A box of 24 samplers well exceeds 40 kg. Considering that sampling fields are not necessarily easily accessible by vehicle, taking hundreds of samples in the field is generally a tough task for everyone. There is a different type of sampler, which is comprised of a much smaller copper tube (6 mm in diameter and 100 mm long for our case) with clamps and a semi-permeable membrane filter. It is sunk into water and left there for dissolved gases to diffuse into the sampler until their concentrations in water become equilibrated with those in the tube. This diffusion sampler is small and easy to handle in the field; it has an advantage over conventional copper tubes, as the diffusion sampler collects gases so that there is no gas extraction process needed before isotope analysis. However, this method requires an equilibration time of 24 hours or more, which could result in lower time-efficiency for sampling work. In order to enable time-efficient and less-painstaking sampling of noble gases dissolved in surface and groundwater, we have developed a portable and self-powered sampling device specified to noble gas analysis by mass spectrometer

  12. 40 CFR 1065.341 - CVS and batch sampler verification (propane check).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false CVS and batch sampler verification... Measurements § 1065.341 CVS and batch sampler verification (propane check). (a) A propane check serves as a CVS... also serves as a batch-sampler verification to determine if there is a discrepancy in a batch...

  13. 50 CFR 697.12 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... must: (1) Notify the sea sampler/observer of any sea turtles, marine mammals, or other specimens taken by the vessel. (2) Provide the sea sampler/observer with sea turtles, marine mammals, or other... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false At-sea sea sampler/observer coverage....

  14. 50 CFR 697.12 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... must: (1) Notify the sea sampler/observer of any sea turtles, marine mammals, or other specimens taken by the vessel. (2) Provide the sea sampler/observer with sea turtles, marine mammals, or other... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false At-sea sea sampler/observer coverage....

  15. 50 CFR 697.12 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... must: (1) Notify the sea sampler/observer of any sea turtles, marine mammals, or other specimens taken by the vessel. (2) Provide the sea sampler/observer with sea turtles, marine mammals, or other... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false At-sea sea sampler/observer coverage....

  16. 50 CFR 697.12 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... must: (1) Notify the sea sampler/observer of any sea turtles, marine mammals, or other specimens taken by the vessel. (2) Provide the sea sampler/observer with sea turtles, marine mammals, or other... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false At-sea sea sampler/observer coverage....

  17. 50 CFR 697.12 - At-sea sea sampler/observer coverage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... must: (1) Notify the sea sampler/observer of any sea turtles, marine mammals, or other specimens taken by the vessel. (2) Provide the sea sampler/observer with sea turtles, marine mammals, or other... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false At-sea sea sampler/observer coverage....

  18. Portable miniature sampler for potential airborne carcinogens in microenvironments: Phase 2, evaluation

    NASA Astrophysics Data System (ADS)

    West, D. S.; Hodgson, F. N.; Brooks, J. J.; Heflin, C. L.; Hughes, T. W.

    1981-09-01

    A portable sampling system was developed for the collection and concentration of a broad range of organic compounds from ambient air. The system is based on the use of three solid sorbent materials (Tenax-GC, Porapak R, and Ambersorb XE-340 arranged in series) through which air is drawn by a portable battery powered pump. Two different portable pumps (DuPont P4000 and Spectrex PAS 3000) were used to power the portable sampling device in field evaluations of the system. The system was evaluated in field studies conducted in Dayton, Ohio; Los Angeles, California; Houston Texas; Niagara Falls, New York; Research Triangle Park, North Carolina; and Cincinnati, Ohio. Both indoor and outdoor environments were included among those sampled.

  19. Sub-micron particle sampler apparatus

    DOEpatents

    Gay, Don D.; McMillan, William G.

    1987-01-01

    Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

  20. Wind tunnel evaluation of the RAAMP sampler. Final report

    SciTech Connect

    Vanderpool, R.W.; Peters, T.M.

    1994-11-01

    Wind tunnel tests of the Department of Energy RAAMP (Radioactive Atmospheric Aerosol Monitoring Program) monitor have been conducted at wind speeds of 2 km/hr and 24 km/hr. The RAAMP sampler was developed based on three specific performance objectives: (1) meet EPA PM10 performance criteria, (2) representatively sample and retain particles larger than 10 {micro}m for later isotopic analysis, (3) be capable of continuous, unattended operation for time periods up to 2 months. In this first phase of the evaluation, wind tunnel tests were performed to evaluate the sampler as a potential candidate for EPA PM10 reference or equivalency status. As an integral part of the project, the EPA wind tunnel facility was fully characterized at wind speeds of 2 km/hr and 24 km/hr in conjunction with liquid test aerosols of 10 {micro}m aerodynamic diameter. Results showed that the facility and its operating protocols met or exceeded all 40 CFR Part 53 acceptance criteria regarding PM10 size-selective performance evaluation. Analytical procedures for quantitation of collected mass deposits also met 40 CFR Part 53 criteria. Modifications were made to the tunnel`s test section to accommodate the large dimensions of the RAAMP sampler`s instrument case.

  1. PARTICULATE ORGANIC CARBON MEASUREMENTS COLLECTED WITH LOW FLOW PERSONAL SAMPLERS

    EPA Science Inventory

    EPA's National Exposure Research Laboratory and the Research Triangle Institute (RTI) have conducted a particulate matter (PM) personal exposure study in Research Triangle Park, NC. Particulate carbon was sampled with pre-fired quartz filters using low flow PM2.5 samplers (2 L...

  2. School-Based Health Centers. Technical Assistance Sampler.

    ERIC Educational Resources Information Center

    California Univ., Los Angeles. Center for Mental Health in Schools.

    The rapid growth in the number of school-based health centers reflects the interest schools and communities have for this approach to the delivery of health care to children and adolescents. This technical assistance sampler contains information about resources for those developing or operating school-based health centers. The first section…

  3. Polyurethane foam (PUF) passive samplers for monitoring phenanthrene in stormwater.

    PubMed

    Dou, Yueqin; Zhang, Tian C; Zeng, Jing; Stansbury, John; Moussavi, Massoum; Richter-Egger, Dana L; Klein, Mitchell R

    2016-04-01

    Pollution from highway stormwater runoff has been an increasing area of concern. Many structural Best Management Practices (BMPs) have been implemented for stormwater treatment and management. One challenge for these BMPs is to sample stormwater and monitor BMP performance. The main objective of this study was to evaluate the feasibility of using polyurethane foam (PUF) passive samplers (PSs) for sampling phenanthrene (PHE) in highway stormwater runoff and BMPs. Tests were conducted using batch reactors, glass-tube columns, and laboratory-scale BMPs (bioretention cells). Results indicate that sorption for PHE by PUF is mainly linearly relative to time, and the high sorption capacity allows the PUF passive sampler to monitor stormwater events for months or years. The PUF passive samplers could be embedded in BMPs for monitoring influent and effluent PHE concentrations. Models developed to link the results of batch and column tests proved to be useful for determining removal or sorption parameters and performance of the PUF-PSs. The predicted removal efficiencies of BMPs were close to the real values obtained from the control columns with errors ranging between -8.46 and 1.52%. This research showed that it is possible to use PUF passive samplers for sampling stormwater and monitoring the performance of stormwater BMPs, which warrants the field-scale feasibility studies in the future. PMID:26942631

  4. Student Sampler: Facts in Brief on North Carolina

    ERIC Educational Resources Information Center

    North Carolina Department of Public Instruction, 2006

    2006-01-01

    This student sampler has been compiled to assist North Carolina students (4th and 8th grade) in their study of North Carolina. It is designed to introduce them to the people, places and events that have shaped North Carolina history. Topics include state symbols, descriptions of the state flag, and seal, the lyrics to the state song, and the…

  5. Stress analysis of portable safety platform (Core Sampler Truck)

    SciTech Connect

    Ziada, H.H.

    1995-03-30

    This document provides the stress analysis and evaluation of the portable platform of the rotary mode core sampler truck No. 2 (RMCST {number_sign}2). The platform comprises railing, posts, deck, legs, and a portable ladder; it is restrained from lateral motion by means of two brackets added to the drill-head service platform.

  6. Polyurethane foam (PUF) passive samplers for monitoring phenanthrene in stormwater.

    PubMed

    Dou, Yueqin; Zhang, Tian C; Zeng, Jing; Stansbury, John; Moussavi, Massoum; Richter-Egger, Dana L; Klein, Mitchell R

    2016-04-01

    Pollution from highway stormwater runoff has been an increasing area of concern. Many structural Best Management Practices (BMPs) have been implemented for stormwater treatment and management. One challenge for these BMPs is to sample stormwater and monitor BMP performance. The main objective of this study was to evaluate the feasibility of using polyurethane foam (PUF) passive samplers (PSs) for sampling phenanthrene (PHE) in highway stormwater runoff and BMPs. Tests were conducted using batch reactors, glass-tube columns, and laboratory-scale BMPs (bioretention cells). Results indicate that sorption for PHE by PUF is mainly linearly relative to time, and the high sorption capacity allows the PUF passive sampler to monitor stormwater events for months or years. The PUF passive samplers could be embedded in BMPs for monitoring influent and effluent PHE concentrations. Models developed to link the results of batch and column tests proved to be useful for determining removal or sorption parameters and performance of the PUF-PSs. The predicted removal efficiencies of BMPs were close to the real values obtained from the control columns with errors ranging between -8.46 and 1.52%. This research showed that it is possible to use PUF passive samplers for sampling stormwater and monitoring the performance of stormwater BMPs, which warrants the field-scale feasibility studies in the future.

  7. 7 CFR 52.29 - Who may become licensed sampler.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... MARKETING ACT OF 1946 PROCESSED FRUITS AND VEGETABLES, PROCESSED PRODUCTS THEREOF, AND CERTAIN OTHER PROCESSED FOOD PRODUCTS 1 Regulations Governing Inspection and Certification Licensing of Samplers and... processed products under the regulations in this part except as to identification and condition of...

  8. 7 CFR 52.29 - Who may become licensed sampler.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT PROCESSED FRUITS AND VEGETABLES, PROCESSED PRODUCTS THEREOF, AND CERTAIN OTHER PROCESSED FOOD PRODUCTS 1 Regulations Governing Inspection and... samplers shall have no authority to inspect processed products under the regulations in this part except...

  9. 7 CFR 52.29 - Who may become licensed sampler.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT PROCESSED FRUITS AND VEGETABLES, PROCESSED PRODUCTS THEREOF, AND CERTAIN OTHER PROCESSED FOOD PRODUCTS 1 Regulations Governing Inspection and... samplers shall have no authority to inspect processed products under the regulations in this part except...

  10. 7 CFR 52.29 - Who may become licensed sampler.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... MARKETING ACT OF 1946 PROCESSED FRUITS AND VEGETABLES, PROCESSED PRODUCTS THEREOF, AND CERTAIN OTHER PROCESSED FOOD PRODUCTS 1 Regulations Governing Inspection and Certification Licensing of Samplers and... processed products under the regulations in this part except as to identification and condition of...

  11. Fluidic Sampler. Tanks Focus Area. OST Reference No. 2007

    SciTech Connect

    None, None

    1999-09-01

    Problem Definition; Millions of gallons of radioactive and hazardous wastes are stored in underground tanks across the U.S. Department of Energy (DOE) complex. To manage this waste, tank operators need safe, cost-effective methods for mixing tank material, transferring tank waste between tanks, and collecting samples. Samples must be collected at different depths within storage tanks containing various kinds of waste including salt, sludge, and supernatant. With current or baseline methods, a grab sampler or a core sampler is inserted into the tank, waste is maneuvered into the sample chamber, and the sample is withdrawn from the tank. The mixing pumps in the tank, which are required to keep the contents homogeneous, must be shut down before and during sampling to prevent airborne releases. These methods are expensive, require substantial hands-on labor, increase the risk of worker exposure to radiation, and often produce nonrepresentative and unreproducible samples. How It Works: The Fluidic Sampler manufactured by AEA Technology Engineering Services, Inc., enables tank sampling to be done remotely with the mixing pumps in operation. Remote operation minimizes the risk of exposure to personnel and the possibility of spills, reducing associated costs. Sampling while the tank contents are being agitated yields consistently homogeneous, representative samples and facilitates more efficient feed preparation and evaluation of the tank contents. The above-tank portion of the Fluidic Sampler and the replacement plug and pipework that insert through the tank top are shown.

  12. FIELD EVALUATION OF A HIGH-VOLUME DICHOTOMOUS SAMPLER

    EPA Science Inventory

    This study presents the field evaluation of a high-volume dichotomous sampler that collects coarse (PM10-2.5) and fine (PM2.5) particulate matter. The key feature of this device is the utilization of a round-nozzle virtual impactor with a 50% cutpoint at 2.5 5m to split PM10 into...

  13. Cache domains that are homologous to, but different from PAS domains comprise the largest superfamily of extracellular sensors in prokaryotes

    DOE PAGES

    Upadhyay, Amit A.; Fleetwood, Aaron D.; Adebali, Ogun; Finn, Robert D.; Zhulin, Igor B.; Schlessinger, Avner

    2016-04-06

    Cellular receptors usually contain a designated sensory domain that recognizes the signal. Per/Arnt/Sim (PAS) domains are ubiquitous sensors in thousands of species ranging from bacteria to humans. Although PAS domains were described as intracellular sensors, recent structural studies revealed PAS-like domains in extracytoplasmic regions in several transmembrane receptors. However, these structurally defined extracellular PAS-like domains do not match sequence-derived PAS domain models, and thus their distribution across the genomic landscape remains largely unknown. Here we show that structurally defined extracellular PAS-like domains belong to the Cache superfamily, which is homologous to, but distinct from the PAS superfamily. Our newly builtmore » computational models enabled identification of Cache domains in tens of thousands of signal transduction proteins including those from important pathogens and model organisms.Moreover, we show that Cache domains comprise the dominant mode of extracellular sensing in prokaryotes.« less

  14. Cache Domains That are Homologous to, but Different from PAS Domains Comprise the Largest Superfamily of Extracellular Sensors in Prokaryotes.

    PubMed

    Upadhyay, Amit A; Fleetwood, Aaron D; Adebali, Ogun; Finn, Robert D; Zhulin, Igor B

    2016-04-01

    Cellular receptors usually contain a designated sensory domain that recognizes the signal. Per/Arnt/Sim (PAS) domains are ubiquitous sensors in thousands of species ranging from bacteria to humans. Although PAS domains were described as intracellular sensors, recent structural studies revealed PAS-like domains in extracytoplasmic regions in several transmembrane receptors. However, these structurally defined extracellular PAS-like domains do not match sequence-derived PAS domain models, and thus their distribution across the genomic landscape remains largely unknown. Here we show that structurally defined extracellular PAS-like domains belong to the Cache superfamily, which is homologous to, but distinct from the PAS superfamily. Our newly built computational models enabled identification of Cache domains in tens of thousands of signal transduction proteins including those from important pathogens and model organisms. Furthermore, we show that Cache domains comprise the dominant mode of extracellular sensing in prokaryotes.

  15. Cache Domains That are Homologous to, but Different from PAS Domains Comprise the Largest Superfamily of Extracellular Sensors in Prokaryotes.

    PubMed

    Upadhyay, Amit A; Fleetwood, Aaron D; Adebali, Ogun; Finn, Robert D; Zhulin, Igor B

    2016-04-01

    Cellular receptors usually contain a designated sensory domain that recognizes the signal. Per/Arnt/Sim (PAS) domains are ubiquitous sensors in thousands of species ranging from bacteria to humans. Although PAS domains were described as intracellular sensors, recent structural studies revealed PAS-like domains in extracytoplasmic regions in several transmembrane receptors. However, these structurally defined extracellular PAS-like domains do not match sequence-derived PAS domain models, and thus their distribution across the genomic landscape remains largely unknown. Here we show that structurally defined extracellular PAS-like domains belong to the Cache superfamily, which is homologous to, but distinct from the PAS superfamily. Our newly built computational models enabled identification of Cache domains in tens of thousands of signal transduction proteins including those from important pathogens and model organisms. Furthermore, we show that Cache domains comprise the dominant mode of extracellular sensing in prokaryotes. PMID:27049771

  16. Cache Domains That are Homologous to, but Different from PAS Domains Comprise the Largest Superfamily of Extracellular Sensors in Prokaryotes

    PubMed Central

    Upadhyay, Amit A.; Fleetwood, Aaron D.; Adebali, Ogun; Finn, Robert D.; Zhulin, Igor B.

    2016-01-01

    Cellular receptors usually contain a designated sensory domain that recognizes the signal. Per/Arnt/Sim (PAS) domains are ubiquitous sensors in thousands of species ranging from bacteria to humans. Although PAS domains were described as intracellular sensors, recent structural studies revealed PAS-like domains in extracytoplasmic regions in several transmembrane receptors. However, these structurally defined extracellular PAS-like domains do not match sequence-derived PAS domain models, and thus their distribution across the genomic landscape remains largely unknown. Here we show that structurally defined extracellular PAS-like domains belong to the Cache superfamily, which is homologous to, but distinct from the PAS superfamily. Our newly built computational models enabled identification of Cache domains in tens of thousands of signal transduction proteins including those from important pathogens and model organisms. Furthermore, we show that Cache domains comprise the dominant mode of extracellular sensing in prokaryotes. PMID:27049771

  17. The Parkinson Anxiety Scale (PAS): development and validation of a new anxiety scale.

    PubMed

    Leentjens, Albert F G; Dujardin, Kathy; Pontone, Gregory M; Starkstein, Sergio E; Weintraub, Daniel; Martinez-Martin, Pablo

    2014-07-01

    Existing anxiety rating scales have limited construct validity in patients with Parkinson's disease (PD). This study was undertaken to develop and validate a new anxiety rating scale, the Parkinson Anxiety Scale (PAS), that would overcome the limitations of existing scales. The general structure of the PAS was based on the outcome of a Delphi procedure. Item selection was based on a canonical correlation analysis and a Rasch analysis of items of the Hamilton Anxiety Rating Scale (HARS) and the Beck Anxiety Inventory (BAI) from a previously published study. Validation was done in a cross-sectional international multicenter study involving 362 patients with idiopathic PD. Patients underwent a single screening session in which the PAS was administered, along with the Hamilton Depression Rating Scale, the HARS, and the BAI. The Mini International Neuropsychiatric Interview was administered to establish Diagnostic and Statistical Manual of Mental Disorders (DSM) diagnoses of anxiety and depressive disorders. The PAS is a 12-item observer or patient-rated scale with three subscales, for persistent, episodic anxiety and avoidance behavior. Properties for acceptability and reliability met predetermined criteria. The convergent and known groups validity was good. The scale has a satisfactory factorial structure. The area under the receiver operating characteristics curve and Youden index of the PAS are higher than that of existing anxiety rating scales. The PAS is a reliable and valid anxiety measure for use in PD patients. It is easy and brief to administer, and has better clinimetric properties than existing anxiety rating scales. The sensitivity to change of the PAS remains to be assessed.

  18. Development and evaluation of personal respirable particulate sampler (PRPS)

    NASA Astrophysics Data System (ADS)

    Lee, Seung Joo; Demokritou, Philip; Koutrakis, Petros; Delgado-Saborit, Juana M.

    This paper presents the development, laboratory evaluation, and field tests of a personal respirable particulate sampler (PRPS). The PRPS is designed as a personal sampling system to collect particulate matter (PM 0.5, PM 1.0, PM 2.5, PM 4.5, and PM 10) and gaseous pollutants, including O 3, SO 2, and NO 2. It operates at a flow rate of 5.0 LPM and consists of five selectable impaction stages (with cutpoints of 10, 4.5, 2.5, 1.0, and 0.5 μm), a backup filter, and two diffusion passive samplers. In each impaction stage, particles are collected onto a polyurethane foam (PUF) substrate. This substrate, using no adhesive, was shown to have minimum particle bounce and re-entrainment. A backup 37 mm Teflon membrane filter is used downstream to collect particles smaller than the cutoff diameter of the final impaction stage. The impaction stage cutpoints were characterized in the laboratory using artificially generated polydisperse aerosols. Particle losses for each stage were found to be acceptably low. The performance of the PRPS was also compared with that of a collocated micro-orifice cascade impactor (MOI) and real-time particle sizing instruments (SMPS/APS) in laboratory experiments using artificially generated particles. The size distributions measured by the PRPS were found to be much closer to those measured by the real-time particle sizing instruments than to those measured by the MOI. A field PM intercomparison study was also conducted using the PRPS and three reference samplers, the Harvard Impactor (HI), the USEPA PM 2.5 Well Impactor Ninety Six (WINS), and the Harvard Personal Environmental Monitor (Harvard PEM) sampler. The PM 10, PM 2.5, and sulfate concentrations measured by PRPS were in a very good agreement with those obtained from the reference samplers.

  19. A passive ozone sampler based on a reaction with iodide.

    PubMed

    Yanagisawa, Y

    1994-02-01

    A new passive sampler for ozone and its simple analytical system have been developed. Because it is small and sensitive, the sampler can be used for determining personal exposures to ozone and oxidants and for multilocation measurements. The sampler consists of an electrode, a spacer, and several layers of membrane filters and Teflon meshes. The electrode is a carbon paper disk coated with nylon-6 polymer and potassium iodide. The membrane filters are used to remove interferences. A sampling rate of ozone is controlled by the spacer and Teflon meshes. Iodine is liberated by an oxidation reaction of potassium iodide with ozone. The iodine is stabilized by forming a charge transfer complex with nylon-6 and is accumulated in the nylon-6 layer. The amount of iodine, which is proportional to the level of ozone exposure, is quantified by constant current coulometry. The discharge time of a galvanic battery is measured using the electrode as a positive electrode and a zinc plate as a counter electrode. A time-weighted average concentration of ozone is derived from the discharge time after exposing the electrode to ozone. The effects of various environmental conditions on the sampler's performance were investigated. The results indicated that the sampler showed a linear response to ozone exposure up to 1,450 parts per billion for every hour of use (ppb.hour). The minimum detectable exposure was about 400 ppb.hour. The effects of surface wind velocity, temperature, and humidity were small. However, a relative humidity below 20% resulted in an underestimation of the ozone concentration. Because the electrode requires no pretreatment and the analytical method is very simple, this method is suitable for large-scale studies of personal exposures to ozone and oxidants using multilocation measurements.

  20. Direct analysis of airborne mite allergen (Der f1) in the residential atmosphere by chemifluorescent immunoassay using bioaerosol sampler.

    PubMed

    Miyajima, Kumiko; Suzuki, Yurika; Miki, Daisuke; Arai, Moeka; Arakawa, Takahiro; Shimomura, Hiroji; Shiba, Kiyoko; Mitsubayashi, Kohji

    2014-06-01

    Dermatophagoides farinae allergen (Der f1) is one of the most important indoor allergens associated with allergic diseases in humans. Mite allergen Der f1 is usually associated with particles of high molecular weight; thus, Der f1 is generally present in settled dust. However, a small quantity of Der f1 can be aerosolized and become an airborne component. Until now, a reliable method of detecting airborne Der f1 has not been developed. The aim of this study was to develop a fiber-optic chemifluorescent immunoassay for the detection of airborne Der f1. In this method, the Der f1 concentration measured on the basis of the intensity of fluorescence amplified by an enzymatic reaction between the labeled enzyme by a detection antibody and a fluorescent substrate. The measured Der f1 concentration was in the range from 0.49 to 250 ng/ml and a similar range was found by enzyme-linked immunosorbent assay (ELISA). This method was proved to be highly sensitive to Der f1 compared with other airborne allergens. For the implementation of airborne allergen measurement in a residential environment, a bioaerosol sampler was constructed. The airborne allergen generated by a nebulizer was conveyed to a newly sampler we developed for collecting airborne Der f1. The sampler was composed of polymethyl methacrylate (PMMA) cells for gas/liquid phases and some porous membranes which were sandwiched in between the two phases. Der f1 in air was collected by the sampler and measured using the fiber-optic immunoassay system. The concentration of Der f1 in aerosolized standards was in the range from 0.125 to 2.0 mg/m(3) and the collection rate of the device was approximately 0.2%.

  1. Considerations for sampling inorganic constituents in ground water using diffusion samplers

    USGS Publications Warehouse

    Vroblesky, D.A.; Petkewich, M.D.; Campbell, T.R.; ,

    2002-01-01

    Data indicate that nylon-screen and dialysis diffusion samplers are capable of obtaining concentrations of inorganic solutes in ground water from wells that closely correspond to concentrations obtained by low-flow sampling. Conservative solutes, such as chloride, can be sampled by filling the diffusion samplers with oxygenated water. The samplers should be filled with anaerobic water for sampling redoxsensitive solutes. Oxidation of iron within the samplers, either by using aerobic fill water or by in-well oxygenation events, can lead to erroneous iron concentrations. Lithologic and chemical heterogeneity and sampler placement depth can lead to differences between concentrations from diffusion samples and low-flow samples because of mixing during pumping. A disadvantage of regenerated cellulose dialysis samplers is that they can begin to biodegrade within the two weeks of deployment. Nylon-screen samplers buried beneath streambed sediment along the unnamed tributary in a discharge zone of arseniccontaminated ground water were useful in locating the specific discharge zone.

  2. An assessment of the variability in performance of wet atmospheric deposition samplers

    USGS Publications Warehouse

    Graham, R.C.; Robertson, J.K.; Obal, John

    1987-01-01

    The variability in performance of two brands of wet/dry atmospheric deposition samplers were compared for 1 year at a sincle site. A total of nine samplers were used. Samples were collected weekly and analyzed for pH, specific conductance, common chemical constituents, and sample volume. Additionally, data on the duration of each sampler opening were recorded using a microdatalogger. These data disprove the common perception that samplers remain open throughout a precipitation event. The sensitivity of sampler sensors within the range tested did not have a defineable impact on sample collection. The nonnormal distribution within the data set necessitated application of the nonparametric Friedman Test to assess comparability of sample chemical composition and volume between and within sampler brands. Statistically significant differences existed for most comparisons, however the test did not permit quantification of their magnitudes. Differences in analyte concentrations between samplers were small. (USGS)

  3. Projecting Ammonia Dry Deposition Using Passive Samplers and a Bi-Directional Exchange Model

    NASA Astrophysics Data System (ADS)

    Robarge, W. P.; Walker, J. T.; Austin, R. E.

    2011-12-01

    Animal agriculture within the United States is known to be a source of ammonia (NH3) emissions. Dry deposition of NH3 to terrestrial ecosystems immediately surrounding large local sources of NH3 emissions (e.g. animal feeding operations) is difficult to measure, and is best estimated via models. Presented here are results for a semi-empirical modeling approach for estimating air-surface exchange fluxes of NH3 downwind of a large poultry facility (~ 3.5 million layers) using a bi-directional air-surface exchange model. The modeling domain is the western section of the Pocosin Lakes National Wildlife Refuge in Tyrrell, Washington, and Hyde Counties of eastern North Carolina in the South Atlantic Coastal Plain physiographic region. Vegetation within the modeling domain is primarily pocosin wetlands, characterized by acid (pH 3.6) peat soils and a thick canopy of shrub vegetation (leatherwood (Cyrilla racemiflora), inkberry (Ilex glabra), wax myrtle (Morella cerifera)). Land surrounding the refuge is primarily used for crop production: ~ 28%, 24%, and 45% agricultural in Tyrell, Hyde, and Washington counties, respectively. Ammonia air-surface exchange (flux) was calculated using a two-layer canopy compensation point model developed by Nemitz et al. (2001. Quart. J. Roy. Met. Soc. 127, 815 - 833.) as implemented by Walker et al. (2008. Atmos. Environ., 42, 3407 - 3418.), in which the competing processes of emission and deposition within the foliage-soil system were taken into account by relating the net canopy-scale NH3 flux to the net emission potential of the canopy (i.e., foliage and soil). Ammonia air concentrations were measured using ALPHA passive samplers (Center for Ecology and Hydrology, Edinburgh) along transects to the north and northeast of the poultry facility at distances of 800, 2000 and 3200 m, respectively. Samplers were deployed in duplicate at each location at a height of 5.8 m from July 2008 to July 2010 weekly during warm months and bi-weekly curing

  4. Physico-chemical qualification of a universal portable sampler for aerosols and water-soluble gases

    NASA Astrophysics Data System (ADS)

    Roux, Jean-Maxime; Sarda-Estève, Roland

    2015-10-01

    Developing a universal portable air sampler based on electrostatic precipitation. The challenge is to collect micro and nanoparticles, microorganisms as well as toxic molecules with a portable device. Electrostatic precipitation is an efficient and gentle method to collect airborne microorganisms and preserve their cultivability. But the collection of toxic gases required is not possible in such a device. The collection of such gases requires a liquid into which they have to be solubilized. Two concepts are being evaluated. The first one is based on electrospray. The goal is to investigate the collection efficiency of water-soluble gases. The second concept is based on the semi-humid electrostatic precipitator. Their high collection efficiencies for particles were already demonstrated. In the present study they are both tested with water-soluble gases. Concentrations are measured in the liquid solution by Ion Chromatography and in the gas phase by Proton Transfer Reaction Mass Spectrometry.

  5. Space Data Systems Applications in the iPAS Pathfinder Laboratory

    NASA Technical Reports Server (NTRS)

    Rich, Tom

    2013-01-01

    The iPAS is an integrated hardware/software test and evaluation environment, in support of current and future spacecraft development The iPAS has two main elements. A common avionics, hardware, and software architecture that can be applied over various missions. A common testbed framework that supports integrated hardware/software testing for a variety of applications. The iPAS includes the following (non-flight qualified) components: Core Flight Software (from GSFC). Commercially available Proton and S950 Flight Computer boards. Power and propulsion systems based on representative flight hardware. A realistic flight deck based on the Multi-Purpose Crew Vehicle (MPCV), including realistic flight controls and displays. A Space Data System based on CCSDS protocols.

  6. Faux pas detection and intentional action in Asperger Syndrome. A replication on a French sample.

    PubMed

    Zalla, Tiziana; Sav, Anca-Maria; Stopin, Astrid; Ahade, Sabrina; Leboyer, Marion

    2009-02-01

    In the present study, we investigated mind reading abilities in a group of adults with Asperger Syndrome (AS) by using the faux pas task, an advanced test of theory of mind (Baron-Cohen et al. (1999). Journal of Autism and Developmental Disorders, 29, 407-418). The faux pas is a particular case of a non-intentional action reflecting an involuntary socially inappropriate behavior. Here, individuals with AS over-detected faux pas stories, failed to provide correct justifications of the speaker's behavior and were unaware of the mistaken belief and of the resulting emotional impact, whereas they appeared to be responsive to social rule violations. We hypothesized that because of an impaired theory-of-mind, individuals with AS may develop compensatory cognitive strategies based on overlearned abstract knowledge about normative rules. PMID:18726150

  7. J-PAS: The Javalambre-Physics of the Accelerating Universe Astrophysical Survey

    NASA Astrophysics Data System (ADS)

    Dupke, Renato a.; Benitez, Narciso; Moles, Mariano; Sodre, Laerte; J-PAS Collaboration

    2015-08-01

    The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow band, very wide field Cosmological Survey to be carried out from the Javalambre Astrophysical Observatory in Spain with a dedicated 2.5m telescope and a 4.7deg^2 camera with 1.2Gpix. Starting in 2016, J-PAS will observe 8600 deg^2 of the Northern Sky and measure 0.003(1+z) precision photometric redshifts for nearly 1E08 LRG and ELG galaxies plus several million QSOs, sampling an effective volume of ~14 Gpc^3 up to z = 1.3. J-PAS will also detect and measure the mass of more than a hundred thousand galaxy clusters, setting constrains on Dark Energy which rival those obtained from BAO measurements.The key to the J-PAS potential is its innovative approach the combination of 54 145°A filters, placed 100°A apart, and a multi-degree field of view (FOV) which makes it a powerful “redshift machine”, with the survey speed of a 4000 multiplexing low resolution spectrograph, but many times cheaper and much faster to build. Moreover, since the J-PAS camera is equivalent to a very large, 4.7deg^2 “IFU”, it will produce a time-resolved, 3D image of the Northern Sky with a very wide range of Astrophysical applications in Galaxy Evolution, the nearby Universe and the study of resolved stellar populations. J-PAS will have a lasting legacy value in many areas of Astrophysics, serving as a fundamental dataset for future Cosmological projects.Here, we present the overall description, status and scientific potential of the survey.

  8. J-PAS: The Javalambre-Physics of the Accelerating Universe Astrophysical Survey

    NASA Astrophysics Data System (ADS)

    Dupke, Renato A.; Benitez, Narciso; Moles, Mariano; Sodre, Laerte; Irwin, Jimmy; J-PAS Collaboration

    2016-01-01

    The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow band, very wide field Cosmological Survey to be carried out from the Javalambre Astrophysical Observatory in Spain with a dedicated 2.5m telescope and a 4.7deg^2 camera with 1.2Gpix. Starting in 2016, J-PAS will observe 8600 deg^2 of the Northern Sky and measure 0.003(1+z) precision photometric redshifts for nearly 1E08 LRG and ELG galaxies plus several million QSOs, sampling an effective volume of ~14 Gpc^3 up to z = 1.3. J-PAS will also detect and measure the mass of more than a hundred thousand galaxy clusters, setting constrains on Dark Energy which rival those obtained from BAO measurements.The key to the J-PAS potential is its innovative approach the combination of 54 145°A filters, placed 100°A apart, and a multi-degree field of view (FOV) which makes it a powerful "redshift machine", with the survey speed of a 4000 multiplexing low resolution spectrograph, but many times cheaper and much faster to build. Moreover, since the J-PAS camera is equivalent to a very large, 4.7deg^2 "IFU", it will produce a time-resolved, 3D image of the Northern Sky with a very wide range of Astrophysical applications in Galaxy Evolution, the nearby Universe and the study of resolved stellar populations. J-PAS will have a lasting legacy value in many areas of Astrophysics, serving as a fundamental dataset for future Cosmological projects.Here, we present the overall description, status and scientific potential of the survey.

  9. Pituitary Adenoma With Paraganglioma/Pheochromocytoma (3PAs) and Succinate Dehydrogenase Defects in Humans and Mice

    PubMed Central

    Xekouki, Paraskevi; Szarek, Eva; Bullova, Petra; Giubellino, Alessio; Quezado, Martha; Mastroyannis, Spyridon A.; Mastorakos, Panagiotis; Wassif, Christopher A.; Raygada, Margarita; Rentia, Nadia; Dye, Louis; Cougnoux, Antony; Koziol, Deloris; Sierra, Maria de La Luz; Lyssikatos, Charalampos; Belyavskaya, Elena; Malchoff, Carl; Moline, Jessica; Eng, Charis; Maher, Louis James; Pacak, Karel; Lodish, Maya

    2015-01-01

    Context: Germline mutations in genes coding succinate dehydrogenase (SDH) subunits A, B, C, and D have been identified in familial paragangliomas (PGLs)/pheochromocytomas (PHEOs) and other tumors. We described a GH-secreting pituitary adenoma (PA) caused by SDHD mutation in a patient with familial PGLs. Additional patients with PAs and SDHx defects have since been reported. Design: We studied 168 patients with unselected sporadic PA and with the association of PAs, PGLs, and/or pheochromocytomas, a condition we named the 3P association (3PAs) for SDHx germline mutations. We also studied the pituitary gland and hormonal profile of Sdhb+/− mice and their wild-type littermates at different ages. Results: No SDHx mutations were detected among sporadic PA, whereas three of four familial cases were positive for a mutation (75%). Most of the SDHx-deficient PAs were either prolactinomas or somatotropinomas. Pituitaries of Sdhb+/− mice older than 12 months had an increased number mainly of prolactin-secreting cells and several ultrastructural abnormalities such as intranuclear inclusions, altered chromatin nuclear pattern, and abnormal mitochondria. Igf-1 levels of mutant mice tended to be higher across age groups, whereas Prl and Gh levels varied according to age and sex. Conclusion: The present study confirms the existence of a new association that we termed 3PAs. It is due mostly to germline SDHx defects, although sporadic cases of 3PAs without SDHx defects also exist. Using Sdhb+/− mice, we provide evidence that pituitary hyperplasia in SDHx-deficient cells may be the initial abnormality in the cascade of events leading to PA formation. PMID:25695889

  10. Digital radiography using amorphous selenium: photoconductively activated switch (PAS) readout system.

    PubMed

    Reznik, Nikita; Komljenovic, Philip T; Germann, Stephen; Rowlands, John A

    2008-03-01

    A new amorphous selenium (a-Se) digital radiography detector is introduced. The proposed detector generates a charge image in the a-Se layer in a conventional manner, which is stored on electrode pixels at the surface of the a-Se layer. A novel method, called photoconductively activated switch (PAS), is used to read out the latent x-ray charge image. The PAS readout method uses lateral photoconduction at the a-Se surface which is a revolutionary modification of the bulk photoinduced discharge (PID) methods. The PAS method addresses and eliminates the fundamental weaknesses of the PID methods--long readout times and high readout noise--while maintaining the structural simplicity and high resolution for which PID optical readout systems are noted. The photoconduction properties of the a-Se surface were investigated and the geometrical design for the electrode pixels for a PAS radiography system was determined. This design was implemented in a single pixel PAS evaluation system. The results show that the PAS x-ray induced output charge signal was reproducible and depended linearly on the x-ray exposure in the diagnostic exposure range. Furthermore, the readout was reasonably rapid (10 ms for pixel discharge). The proposed detector allows readout of half a pixel row at a time (odd pixels followed by even pixels), thus permitting the readout of a complete image in 30 s for a 40 cm x 40 cm detector with the potential of reducing that time by using greater readout light intensity. This demonstrates that a-Se based x-ray detectors using photoconductively activated switches could form a basis for a practical integrated digital radiography system. PMID:18404939

  11. [Transport and differentiation of polycyclic aromatic hydrocarbons in air from Dashiwei karst Sinkholes in Guangxi, China].

    PubMed

    Kong, Xiang-Sheng; Qi, Shi-Hua; Sun, Qian; Huang, Bao-Jian

    2012-12-01

    The typical karst Dashiwei Sinkholes located in Leye County, Guangxi were chosen as the study object. The air samples from the opening of Dashiwei Sinkholes to the underground river profiles were collected by polyurethane foam passive samplers (PUF-PAS), and the meteorological parameters were observed. The 16 PAHs were analyzed using GC-MS. The results showed that the total PAHs concentration in air in Dashiwei Sinkholes ranged from 33.76 ng x d(-1) to 150.86 ng x d(-1), with an average of 80.36 ng x d(-1). The mean concentrations in the cliff, the bottom and the underground river profiles were 67.17, 85.36 and 101.67 ng x d(-1), respectively. The 2-3 rings PAHs (including phenanthrene, anthracene, napnthalene and fluorene) accounted for 87.97% of the total of PAHs. The transport and accumulation processes of PAHs in air in Dashiwei Sinkholes were: the ground to the cliff section to the bottom section and then to the underground river, and the total PAHs concentrations showed an obvious increasing tendency with the decrease in altitude or increase in the length of the underground river. Low molecular weight PAHs compounds (including phenanthrene, anthracene, flourene and fluoranthene) in air went through differentiation at the bottom of the west peak, the bottom of the sinkhole and the underground river. The primary sources of PAHs were pyrogenic sources with atmosphere transport. Ambient temperature was the predominating factor influencing the transport and accumulation of gas phase PAHs in Dashiwei Sinkholes, following by wind speed, wind direction and relative humidity. Relative humidity and the temperature were the predominating factors influencing the differentiation, following by wind speed and wind direction. As a whole, a "cold trapping effect" of POPs was showed obviously in Dashiwei Sinkholes.

  12. A Gibbs sampler for motif detection in phylogenetically close sequences

    NASA Astrophysics Data System (ADS)

    Siddharthan, Rahul; van Nimwegen, Erik; Siggia, Eric

    2004-03-01

    Genes are regulated by transcription factors that bind to DNA upstream of genes and recognize short conserved ``motifs'' in a random intergenic ``background''. Motif-finders such as the Gibbs sampler compare the probability of these short sequences being represented by ``weight matrices'' to the probability of their arising from the background ``null model'', and explore this space (analogous to a free-energy landscape). But closely related species may show conservation not because of functional sites but simply because they have not had sufficient time to diverge, so conventional methods will fail. We introduce a new Gibbs sampler algorithm that accounts for common ancestry when searching for motifs, while requiring minimal ``prior'' assumptions on the number and types of motifs, assessing the significance of detected motifs by ``tracking'' clusters that stay together. We apply this scheme to motif detection in sporulation-cycle genes in the yeast S. cerevisiae, using recent sequences of other closely-related Saccharomyces species.

  13. Comparison. US P-61 and Delft sediment samplers

    USGS Publications Warehouse

    Beverage, Joseph P.; Williams, David T.

    1990-01-01

    The Delft Bottle (DB) is a flow-through device designed by the Delft Hydraulic Laboratory (DHL), The Netherlands, to sample sand-sized sediment suspended in streams. The US P-61 sampler was designed by the Federal Interagency Sedimentation Project (FISP) at the St. Anthony Falls Hydraulic Laboratory, Minneapolis, Minnesota, to collect suspended sediment from deep, swift rivers. The results of two point-sampling tests in the United States, the Mississippi River near Vicksburg, Mississippi, in 1983 and the Colorado River near Blythe, California, in 1984, are provided in this report. These studies compare sand-transport rates, rather than total sediment-transport rates, because fine material washes through the DB sampler. In the United States, the commonly used limits for sand-sized material are 0.062 mm to 2.00 mm (Vanoni 1975).

  14. Application of a dialysis sampler to monitor phytoremediation processes.

    PubMed

    Jackson, W Andrew; Martino, Louis; Hirsh, Steven; Wrobel, John; Pardue, John H

    2005-08-01

    A cylindrical dialysis sampler (1.2 m in length; 5 cm in diameter) was designed and constructed to sample small-scale phytoremediation processes in the root zone of poplar trees. The study site was a 183-tree plantation of hybrid poplars located at Aberdeen Proving Ground, Maryland, at the J-Field Area of Concern. The grove was planted in 1996 to intercept a chlorinated solvent plume containing 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA, trichloroethene (TCE) and daughter products. Two dialysis samplers were installed: one directly in the poplar grove (approximately 0.3 m from the trunk of a mature tree) and the other outside of the grove but in the plume. Data collected included concentrations of chlorinated VOCs, organic acids, chloroacetic acids, Cl-, and dissolved gases (ethane, ethene, CH4, CO2). At the control location, the VOC profile was dominated by cis-1,2-dichloroethene (cis-1,2-DCE) and trans-1,2-dichloroethene (trans-1,2-DCE) with concentrations ranging from 0.88-4.5 to 4.4-17.6 mg/L, respectively. Concentrations of VOCs were similar across the vertical profile. At the tree location, 1,1,2,2-TeCA and TCE were the dominant VOCs detected but as opposed to the control location were highly variable within the root zone, with the greatest variability associated with locations in the sampler where roots were observed. This highly variable profile at the tree location is indicative of VOC rhizosphere biodegradation and uptake near the active roots. This variability appears to be on the centimeter scale, emphasizing the importance of these high-resolution samplers for the study of rhizosphere influences.

  15. Periodic acid-Schiff (PAS) staining of immature platelets in donors.

    PubMed

    Pogorelov, Valery M; Beskorovainova, Victoria Ju; Chanieva, Marem I; Dyagileva, Olga A; Naumova, Iren N; Skedina, Marina A

    2012-01-01

    Glycogen in platelets (PLTs) on smears of peripheral blood of 40 donors was investigated by the periodic acid-Schiff (PAS) method. Three groups were formed. Group 1 was consisted of 21 men undergoing the donor selection procedure. Additionally, 9 first-time donors undergoing plateletpheresis (Group 2) and 10 donors who frequently underwent platelet apheresis (Group 3) were studied as a model of relative thrombocytopenia. Cell sizes were measured with the use of a Image Analyzer "ASPBC" (Russia). The training procedure and classification of PAS-blood PLTs were made on the basis of expert evaluation. In this article, we have established three facts. First, the PAS-positive PLT area was larger than that of the PAS-negative cells (9.5 ± 3.6 sq.mkm vs. 3.9 ± 1.3 sq.mkm, p < 0.001, n = 21). The PAS-positivity of PLTs was 23.1 ± 9.2%. Second, the PAS-positivity correlated (r(S) = 0.63, p < 0.05) with the immature platelets fraction (IPF %), determined using Sysmex XE-2100. The mean IPF was 2.1 ± 1.0% (range 0.3-4.6%). Third, using the IPF% values obtained in Group 1, we found a significantly higher level of IPF in the samples both in Group 2 [mean value 4.2 ± 2.0% (range 1.9-7.0), p < 0.01] and in Group 3 [mean value 5.1 ± 2.5% (range 1.2-8.6), p < 0.004] with relative thrombocytopenia [Group 2: median 198 (95% confidence interval, CI 166-227) vs. median 229 (95% CI 206-267), p < 0.05; Group 3: median 142.5 (95% CI 132-173) vs. median 214.5 (95% CI 196-267), p < 0.01] after plateletpheresis. There was also a significant difference between the pre- and post-plateletpheresis for IPF% in Group 2 and Group 3: median 1.7 (95% CI 1.4-4.0) vs. median 4.0 (95% CI 2.7-5.8), p < 0.05 and median 4.0 (95% CI 2.7-6.0) vs. median 5.1 (95% CI 3.3-6.9), p < 0.01. The increased IPF shows a correlation with the PAS positivity [r(S) = 0.5 (p = 0.14) and r(S) = 0.6 (p = 0.05)] which has a tendency to

  16. A sampler for coring sediments in rivers and estuaries

    USGS Publications Warehouse

    Prych, Edmund A.; Hubbell, D.W.

    1966-01-01

    A portable sampler developed to core submerged unconsolidated sediments collects cores that are 180 cm long and 4.75cm in diameter. The sampler is used from a 12-m boat in water depths up to 20 m and in flow velocities up to 1.5m per second to sample river and estuarine deposits ranging from silty clay to medium sand. Even in sand that cannot be penetrated with conventional corers, the sampler achieves easy penetration through the combined application of vibration, suction, and axial force. A piston in the core barrel creates suction, and the suspension system is arranged so that tension on the support cable produces both a downward force on the core barrel and a lateral support against overturning. Samples are usually retained because of slight compaction in the driving head; as a precaution, however, the bottom of the core barrel is covered by a plate that closes after the barrel is withdrawn from the bed. Tests show that sample-retainers placed within the driving head restrict penetration and limit core lengths. Stratification within cores is disrupted little as a result of the sampling process.

  17. A new sampler design for measuring sedimentation in streams

    USGS Publications Warehouse

    Hedrick, Lara B.; Welsh, S.A.; Hedrick, J.D.

    2005-01-01

    Sedimentation alters aquatic habitats and negatively affects fish and invertebrate communities but is difficult to quantify. To monitor bed load sedimentation, we designed a sampler with a 10.16-cm polyvinyl chloride coupling and removable sediment trap. We conducted a trial study of our samplers in riffle and pool habitats upstream and downstream of highway construction on a first-order Appalachian stream. Sediment samples were collected over three 6-week intervals, dried, and separated into five size-classes by means of nested sieves (U.S. standard sieve numbers 4, 8, 14, and 20). Downstream sediment accumulated in size-classes 1 and 2, and the total amount accumulated was significantly greater during all three sampling periods. Size-classes 3 and 4 had significantly greater amounts of sediment for the first two sampling periods at the downstream site. Differences between upstream and downstream sites narrowed during the 5-month sampling period. This probably reflects changes in site conditions, including the addition of more effective sediment control measures after the first 6-week period of the study. The sediment sampler design allowed for long-term placement of traps without continual disturbance of the streambed and was successful at providing repeat measures of sediment at paired sites. ?? Copyright by the American Fisheries Society 2005.

  18. A carbon monoxide passive sampler: Research and development needs

    SciTech Connect

    Traynor, G.W.; Apte, M.G.; Diamond, R.C.; Woods, A.L.

    1991-11-01

    In rare instances, carbon monoxide (CO) levels in houses can reach dangerously high concentrations, causing adverse health effects ranging from mild headaches to, under extreme conditions, death. Hundreds of fatal accidental carbon monoxide poisonings occur each year primarily due to the indoor operation of motor vehicles, the indoor use of charcoal for cooking, the operation of malfunctioning vented and unvented combustion appliances, and the misuse combustion appliances. Because there is a lack of simple, inexpensive, and accurate field sampling instrumentation, it is difficult for gas utilities and researchers to conduct field research studies designed to quantify the concentrations of CO in residences. Determining the concentration of CO in residences is the first step towards identifying the high risk appliances and high-CO environments which pose health risks. Thus, there exists an urgent need to develop and field-validate a CO-quantifying technique suitable for affordable field research. A CO passive sampler, if developed, could fulfill these requirements. Existing CO monitoring techniques are discussed as well as three potential CO-detection methods for use in a CO passive sampler. Laboratory and field research needed for the development and validation of an effective and cost-efficient CO passive sampler are also discussed.

  19. Modeling uptake of hydrophobic organic contaminants into polyethylene passive samplers.

    PubMed

    Thompson, Jay M; Hsieh, Ching-Hong; Luthy, Richard G

    2015-02-17

    Single-phase passive samplers are gaining acceptance as a method to measure hydrophobic organic contaminant (HOC) concentration in water. Although the relationship between the HOC concentration in water and passive sampler is linear at equilibrium, mass transfer models are needed for nonequilibrium conditions. We report measurements of organochlorine pesticide diffusion and partition coefficients with respect to polyethylene (PE), and present a Fickian approach to modeling HOC uptake by PE in aqueous systems. The model is an analytic solution to Fick's second law applied through an aqueous diffusive boundary layer and a polyethylene layer. Comparisons of the model with existing methods indicate agreement at appropriate boundary conditions. Laboratory release experiments on the organochlorine pesticides DDT, DDE, DDD, and chlordane in well-mixed slurries support the model's applicability to aqueous systems. In general, the advantage of the model is its application in the cases of well-agitated systems, low values of polyethylene-water partioning coefficients, thick polyethylene relative to the boundary layer thickness, and/or short exposure times. Another significant advantage is the ability to estimate, or at least bound, the needed exposure time to reach a desired CPE without empirical model inputs. A further finding of this work is that polyethylene diffusivity does not vary by transport direction through the sampler thickness. PMID:25607420

  20. Filter and electrostatic samplers for semivolatile aerosols: physical artifacts.

    PubMed

    Volckens, John; Leith, David

    2002-11-01

    Adsorptive and evaporative artifacts often bias measurements of semivolatile aerosols. Adsorption occurs when the sampling method disrupts the gas-particle partitioning equilibrium. Evaporation occurs because concentrations of semivolatiles are rarely constant over time. Filtration is subject to both adsorptive and evaporative artifacts. By comparison, electrostatic precipitation reduces these artifacts by minimizing the surface area of collected particles without substantially disrupting the gas-particle equilibrium. The extent of these artifacts was determined for filter samplers and electrostatic precipitator samplers for semivolatile alkane aerosols in the laboratory. Adsorption of gas-phase semivolatiles was lower in electrostatic precipitators by factors of 5-100 compared to the filter method. Particle evaporation from the electrostatic sampler was 2.3 times lower than that from TFE-coated glass-fiber filters. Use of a backup filter to correct for compound-specific adsorption artifacts can introduce positive or negative errors to the measured particle-phase concentration due to competition among the adsorbates for available adsorption sites. Adsorption of evaporated particles from the front filter onto the backup filter increased the measured evaporative artifact by a factor of 1.5-2.

  1. Hydrothermal Vent Sampler: Does Life Exist in High Temperature Environments?

    NASA Technical Reports Server (NTRS)

    Rivadeneyra, Cesar R.

    2005-01-01

    The main purpose of this research is to search for the existence of biomass under extreme temperature and pressure conditions to determine the upper bounds of environments on which life can exist. Vents are, simply put, underwater volcano openings located at the bottom of the sea. The conditions at these locations are considerably extreme with pressures of up to 10,000 psi, and enormous temperature gradients. The temperature of the water near these vents is around 400 C, while that of the surrounding water is about 3 C. The extremity of these conditions makes it hard to estimate the existence of life in those environments. I n order to find whether such existence happens, we need to search for biomass inside these vents. The vent sampler is a device that has the purpose of safely and accurately collecting this biomass for examination. This sampler is constituted of a Series of filters of the order of 100-0.2 microns in size. Since this is a 3-year project, it has not concluded yet; however, during the time I contributed to this project, I worked with the mechanical design of this sampler device including the selection, assembly, and testing of the various subsystems and the design and construction of the electronics enclosure.

  2. 47 CFR Appendix B to Part 64 - Priority Access Service (PAS) for National Security and Emergency Preparedness (NSEP)

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PAS to affected entities and individuals. 8. Enlarge the role of the Telecommunications Service...) Army Corps of Engineers leadership; (ii) Power, water and sewage and telecommunications utilities;...

  3. Psychometric Properties and Norms of the German ABC-Community and PAS-ADD Checklist

    ERIC Educational Resources Information Center

    Zeilinger, Elisabeth L.; Weber, Germain; Haveman, Meindert J.

    2011-01-01

    Aim: The aim of the present study was to standardize and generate psychometric evidence of the German language versions of two well-established English language mental health instruments: the "Aberrant Behavior Checklist-Community" (ABC-C) and the "Psychiatric Assessment Schedule for Adults with Developmental Disabilities" (PAS-ADD) Checklist. New…

  4. Crystal structure of the PAS domain of the hEAG potassium channel

    PubMed Central

    Tang, Xue; Shao, Juan; Qin, Xiaohong

    2016-01-01

    KCNH voltage-gated potassium channels play critical roles in regulating cellular functions. The channel is composed of four subunits, each of which contains six transmembrane helices forming the central pore. The cytoplasmic parts of the subunits present a Per–Arnt–Sim (PAS) domain at the N-terminus and a cyclic nucleotide-binding homology domain at the C-terminus. PAS domains are conserved from prokaryotes to eukaryotes and are involved in sensing signals and cellular responses. To better understand the functional roles of PAS domains in KCNH channels, the structure of this domain from the human ether-à-go-go channel (hEAG channel) was determined. By comparing it with the structures of the Homo sapiens EAG-related gene (hERG) channel and the Drosophila EAG-like K+ (dELK) channel and analyzing the structural features of the hEAG channel, it was identified that a hydrophobic patch on the β-sheet may mediate interaction between the PAS domain and other regions of the channel to regulate its functions. PMID:27487920

  5. Peer Relations and the Understanding of Faux Pas: Longitudinal Evidence for Bidirectional Associations

    ERIC Educational Resources Information Center

    Banerjee, Robin; Watling, Dawn; Caputi, Marcella

    2011-01-01

    Research connecting children's understanding of mental states to their peer relations at school remains scarce. Previous work by the authors demonstrated that children's understanding of mental states in the context of a faux pas--a social blunder involving unintentional insult--is associated with concurrent peer rejection. The present report…

  6. Test report for PAS-1 cask certification for shipping payload B

    SciTech Connect

    MERCADO, J.E.

    1998-10-13

    This test report documents the successful inspection and testing to certify two NuPac PAS-1 casks in accordance with US Department of Energy Certificate of Compliance (CoC) USA/9184/B(U). The primary and secondary containment vessels of each cask met the acceptance criteria defined in the CoC and the test plan.

  7. J-PAS: The Javalambre-Physics of the Accelerated Universe Astrophysical Survey

    NASA Astrophysics Data System (ADS)

    Benítez, N.; Dupke, R.; Moles, M.; Sodré, L.; Cenarro, A. J.; Marín Franch, A.; Taylor, K.; Cristóbal, D.; Fernández-Soto, A.; Mendes de Oliveira, C.; Cepa-Nogué, J.; Abramo, L. R.; Alcaniz, J. S.; Overzier, R.; Hernández-Monteagudo, C.; Alfaro, E. J.; Kanaan, A.; Carvano, M.; Reis, R. R. R.; J-PAS Collaboration

    2015-05-01

    J-PAS is a Spanish-Brazilian 8500 deg^2 Cosmological Survey which will be carried out from the Javalambre Observatory with a purpose-built, dedicated 2.5 m telescope and a 4.7 deg^2 camera with 1.2 Gpix. Starting in 2015, J-PAS will use 59 filters to measure high precision 0.003(1+z) photometric redshifts for 90M galaxies plus several million QSOs, about 50 times more than the largest current spectroscopic survey, sampling an effective volume of ˜ 14 Gpc^3 up to z=1.3. J-PAS will not only be first radial BAO experiment to reach Stage IV; it will also detect and measure the mass of 7× 10^5 galaxy clusters and groups, setting constrains on Dark Energy which rival those obtained from BAO measurements. The combination of a set of 145 Å NB filters, placed 100 Å apart, and a multi-degree field of view is a powerful ``redshift machine'', equivalent to a 4000 multiplexing spectrograph, but many times cheaper to build. The J-PAS camera is equivalent to a very large, 4.7 deg^2 ``IFU'', which will produce a time-resolved, 3D image of the Northern Sky with a very wide range of scientific applications in Galaxy Evolution, Stellar Physics and the Solar System.

  8. Searching for planetary nebulae at the Galactic halo via J-PAS

    NASA Astrophysics Data System (ADS)

    Gonçalves, Denise R.; Aparício-Villegas, T.; Akras, S.; Cortesi, A.; Borges-Fernandes, M.; Daflon, S.; Pereira, C. B.; Lorenz-Martins, S.; Marcolino, W.; Kanaan, A.; Viironen, K.; de Oliveira, C. Mendes; Molino, A.; Ederoclite, A.

    2016-08-01

    The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow-band imaging, very wide field cosmological survey. It will last 5 years and will observe 8500 sq. deg. of the sky. There will be 54 contiguous narrow-band filters of 145Å FWHM, from 3,500 to 10,000Å. Two broad-band filters will be added at the extremes, UV and IR, plus the 3-g, r, and i- SDSS filters. Thus, J-PAS can be an important tool to search for new planetary nebulae (PNe) at the halo, increasing their numbers, because only 14 of them have been convincingly identified in the literature. Halo PNe are able to reveal precious information for the study of stellar evolution and the early chemical conditions of the Galaxy. The characteristic low continuum and intense emission lines of PNe make them good objects to be searched by J-PAS. Though covering a significantly smaller sky area, data from the ALHAMBRA survey were used to test our J-PAS strategy to search for PNe. Our first results are shown in this contribution.

  9. Exploratory studies of extended storage of apheresis platelets in a platelet additive solution (PAS).

    PubMed

    Slichter, Sherrill J; Corson, Jill; Jones, Mary Kay; Christoffel, Todd; Pellham, Esther; Bailey, S Lawrence; Bolgiano, Doug

    2014-01-01

    To evaluate the poststorage viability of apheresis platelets stored for up to 18 days in 80% platelet additive solution (PAS)/20% plasma, 117 healthy subjects donated platelets using the Haemonetics MCS+, COBE Spectra (Spectra), or Trima Accel (Trima) systems. Control platelets from the same subjects were compared with their stored test PAS platelets by radiolabeling their stored and control platelets with either (51)chromium or (111)indium. Trima platelets met Food and Drug Administration poststorage platelet viability criteria for only 7 days vs almost 13 days for Haemonetics platelets; ie, platelet recoveries after these storage times averaged 44 ± 3% vs 49 ± 3% and survivals were 5.4 ± 0.3 vs 4.6 ± 0.3 days, respectively. The differences in storage duration are likely related to both the collection system and the storage bag. The Spectra and Trima platelets were hyperconcentrated during collection, and PAS was added, whereas the Haemonetics platelets were elutriated with PAS, which may have resulted in less collection injury. When Spectra and Trima platelets were stored in Haemonetics' bags, poststorage viability was significantly improved. Platelet viability is better maintained in vitro than in vivo, allowing substantial increases in platelet storage times. However, implementation will require resolution of potential bacterial overgrowth during storage.

  10. Crystal structure of the PAS domain of the hEAG potassium channel.

    PubMed

    Tang, Xue; Shao, Juan; Qin, Xiaohong

    2016-08-01

    KCNH voltage-gated potassium channels play critical roles in regulating cellular functions. The channel is composed of four subunits, each of which contains six transmembrane helices forming the central pore. The cytoplasmic parts of the subunits present a Per-Arnt-Sim (PAS) domain at the N-terminus and a cyclic nucleotide-binding homology domain at the C-terminus. PAS domains are conserved from prokaryotes to eukaryotes and are involved in sensing signals and cellular responses. To better understand the functional roles of PAS domains in KCNH channels, the structure of this domain from the human ether-à-go-go channel (hEAG channel) was determined. By comparing it with the structures of the Homo sapiens EAG-related gene (hERG) channel and the Drosophila EAG-like K(+) (dELK) channel and analyzing the structural features of the hEAG channel, it was identified that a hydrophobic patch on the β-sheet may mediate interaction between the PAS domain and other regions of the channel to regulate its functions. PMID:27487920

  11. [Adaptation and French validation of physical anhedonia scale: PAS (Chapman and Chapman, 1978)].

    PubMed

    Loas, G

    1993-01-01

    This work presents the validation of the French version of the Physical Anhedonia Scale (PAS). The scale's validity, fidelity and reliability were studied in two groups: 61 normal subjects, 61 subjects who met RDC criteria for major depressive disorder. The internal consistency and reliability were determined by the Kuder-Richardson coefficient (KR 20) which values were 0.7 in the control group and 0.83 in the depressed group. The internal consistency was also studied by the correlation between each item and the PAS total score using the point biserial coefficient. 54 items on 61 showed a significant correlation coefficient which ranged from 0.18 to 0.59. For the concurrent validity we studied the correlation (Pearson correlation coefficient) between the PAS and the French version of the Fawcett-Clark Pleasure Capacity Scale (FCPCS). The values were -0.31 (p = 0.014) in the control group and -0.53 (p = 0.00001) in the depressed group. These values show the degree of correlation between the two measures of anhedonia. The French version of the PAS is reliable and allow us to study the physical anhedonia in psychopathology.

  12. Summary report on the design of the retained gas sampler system (retained gas sampler, extruder and extractor)

    SciTech Connect

    Wootan, D.W.; Bolden, R.C.; Bridges, A.E.; Cannon, N.S.; Chastain, S.A.; Hey, B.E.; Knight, R.C.; Linschooten, C.G.; Pitner, A.L.; Webb, B.J.

    1994-09-29

    This document summarizes work performs in Fiscal Year 1994 to develop the three main components of Retained Gas Sampler System (RGSS). These primary components are the Retained Gas Sampler (RGS), the Retained Gas Extruder (RGE), and the Retained Gas Extractor (RGEx). The RGS is based on the Westinghouse Hanford Company (WHC) Universal Sampler design, and includes modifications to reduce gas leakage. The primary data priorities for the RGSS are to measure the void fraction and the flammable gas concentration in the waste sample. Significant progress has been made in developing the RGSS. The RGSS is being developed by WHC to extract a representative waste sample from a Flammable Gas Watch List Tanks and to measure both the amount and composition of free and {open_quotes}bound{close_quotes} gases. Sudden releases of flammable gas mixtures are a safety concern for normal waste storage operations and eventual waste retrieval. Flow visualization testing was used to identify important fluid dynamic issues related to the sampling process. The primary data priorities for the RGSS are to measure the void fraction and the flammable gas concentration in the waste sample. The safety analysis for the RGSS is being performed by Los Alamos National Laboratory and is more than sixty percent (60%) complete.

  13. J-PAS: The Javalambre Physics of the Accelerated Universe Astrophysical Survey

    NASA Astrophysics Data System (ADS)

    Cepa, J.; Benítez, N.; Dupke, R.; Moles, M.; Sodré, L.; Cenarro, A. J.; Marín-Franch, A.; Taylor, K.; Cristóbal, D.; Fernández-Soto, A.; Mendes de Oliveira, C.; Abramo, L. R.; Alcaniz, J. S.; Overzier, R.; Hernández-Monteagudo, A.; Alfaro, E. J.; Kanaan, A.; Carvano, M.; Reis, R. R. R.; J-PAS Team

    2016-10-01

    The Javalambre Physics of the Accelerated Universe Astrophysical Survey (J-PAS) is a narrow band, very wide field Cosmological Survey to be carried out from the Javalambre Observatory in Spain with a purpose-built, dedicated 2.5 m telescope and a 4.7 sq.deg. camera with 1.2 Gpix. Starting in late 2016, J-PAS will observe 8500 sq.deg. of Northern Sky and measure Δz˜0.003(1+z) photo-z for 9× 107 LRG and ELG galaxies plus several million QSOs, sampling an effective volume of ˜ 14 Gpc3 up to z=1.3 and becoming the first radial BAO experiment to reach Stage IV. J-PAS will detect 7× 105 galaxy clusters and groups, setting constraints on Dark Energy which rival those obtained from its BAO measurements. Thanks to the superb characteristics of the site (seeing ˜ 0.7 arcsec), J-PAS is expected to obtain a deep, sub-arcsec image of the Northern sky, which combined with its unique photo-z precision will produce one of the most powerful cosmological lensing surveys before the arrival of Euclid. J-PAS's unprecedented spectral time domain information will enable a self-contained SN survey that, without the need for external spectroscopic follow-up, will detect, classify and measure σz˜ 0.5 redshifts for ˜ 4000 SNeIa and ˜ 900 core-collapse SNe. The key to the J-PAS potential is its innovative approach: a contiguous system of 54 filters with 145 Å width, placed 100 Å apart over a multi-degree FoV is a powerful redshift machine, with the survey speed of a 4000 multiplexing low resolution spectrograph, but many times cheaper and much faster to build. The J-PAS camera is equivalent to a 4.7 sq.deg. IFU and it will produce a time-resolved, 3D image of the Northern Sky with a very wide range of Astrophysical applications in Galaxy Evolution, the nearby Universe and the study of resolved stellar populations.

  14. Spatial and seasonal variations of atmospheric organochlorine pesticides along the plain-mountain transect in central China: Regional source vs. long-range transport and air-soil exchange

    NASA Astrophysics Data System (ADS)

    Qu, Chengkai; Xing, Xinli; Albanese, Stefano; Doherty, Angela; Huang, Huanfang; Lima, Annamaria; Qi, Shihua; De Vivo, Benedetto

    2015-12-01

    Polyurethane foam (PUF) disk passive air samplers (PAS) were deployed to measure spatiality and seasonality of atmospheric OCPs in Jianghan Plain (JHP) and Western Hubei Mountain (WHM), to make a preliminary explorative study of the source-sink relationship of organochlorine pesticides (OCPs) and their association with the monsoon. The concentrations of individual OCPs in the JHP were generally higher than those in the WHM. Significantly high levels of DDTs and Endosulfan were found in the spring and summer, HCB was found in autumn and winter, and HCHs displayed uniform distributions. Compared with the levels of 2005, a significant decrease of atmospheric HCHs, DDTs and HCB was observed, whereas an increase in Endosulfan was observed. The air-soil equilibrium status of OCPs suggested that Dajiuhu (DJH) soils are likely to be a sink for OCPs, and JHP soils are acting as the emitter, contaminating the atmosphere at certain monitoring stations. Backward air trajectory analysis demonstrated that the seasonal fluctuation of atmospheric DDTs, HCB and Endosulfan at the DJH site were closely associated with the variations of the East Asian monsoon.

  15. A sample-freezing drive shoe for a wire line piston core sampler

    USGS Publications Warehouse

    Murphy, F.; Herkelrath, W.N.

    1996-01-01

    Loss of fluids and samples during retrieval of cores of saturated, noncohesive sediments results in incorrect measures of fluid distributions and an inaccurate measure of the stratigraphic position of the sample. To reduce these errors, we developed a hollow drive shoe that freezes in place the lowest 3 inches (75 mm) of a 1.88-inch-diameter (48 mm), 5-foot-long (1.5 m) sediment sample taken using a commercial wire line piston core sampler. The end of the core is frozen by piping liquid carbon dioxide at ambient temperature through a steel tube from a bottle at the land surface to the drive shoe where it evaporates and expands, cooling the interior surface of the shoe to about -109??F (-78??C). Freezing a core end takes about 10 minutes. The device was used to collect samples for a study of oil-water-air distributions, and for studies of water chemistry and microbial activity in unconsolidated sediments at the site of an oil spill near Bemidji, Minnesota. Before freezing was employed, samples of sandy sediments from near the water table sometimes flowed out of the core barrel as the sampler was withdrawn. Freezing the bottom of the core allowed for the retention of all material that entered the core barrel and lessened the redistribution of fluids within the core. The device is useful in the unsaturated and shallow saturated zones, but does not freeze cores well at depths greater than about 20 feet (6 m) below water, possibly because the feed tube plugs with dry ice with increased exhaust back-pressure, or because sediment enters the annulus between the core barrel and the core barrel liner and blocks the exhaust.

  16. Quartz in coal dust deposited on internal surface of respirable size selective samplers.

    PubMed

    Soo, Jhy-Charm; Lee, Taekhee; Kashon, Michael; Kusti, Mohannad; Harper, Martin

    2014-01-01

    The objective of the present study is to quantify quartz mass in coal dust deposited on the internal cassette surface of respirable size-selective samplers. Coal dust was collected with four different respirable size-selective samplers (10 mm Dorr-Oliver nylon [Sensidyne, St. Petersburg, Fla.], SKC Aluminum [SKC Inc., Eighty Four, Pa.], BGI4L [BGI USA Inc., Waltham, Mass.], and GK2.69 cyclones [BGI USA Inc.]) with two different cassette types (polystyrene and static-dissipative polypropylene cassettes). The coal dust was aerosolized in a calm air chamber by using a fluidized bed aerosol generator without neutralization under the assumption that the procedure is similar to field sampling conditions. The mass of coal dust was measured gravimetrically and quartz mass was determined by Fourier transform infrared spectroscopy according to the National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods, Method 7603. The mass fractions of the total quartz sample on the internal cassette surface are significantly different between polystyrene and static-dissipative cassettes for all cyclones (p < 0.05). No consistent relationship between quartz mass on cassette internal surface and coal dust filter mass was observed. The BGI4L cyclone showed a higher (but not significantly) and the GK2.69 cyclone showed a significantly lower (p < 0.05) internal surface deposit quartz mass fraction for polystyrene cassettes compared to other cyclones. This study confirms previous observations that the interior surface deposits in polystyrene cassettes attached to cyclone pre-selectors can be a substantial part of the sample, and therefore need to be included in any analysis for accurate exposure assessment. On the other hand, the research presented here supports the position that the internal surface deposits in static-dissipative cassettes used with size-selective cyclones are negligible and that it is only necessary to analyze the filter catch.

  17. Passive sampling of glycol ethers and their acetates in indoor air.

    PubMed

    Plaisance, H; Desmettres, P; Leonardis, T; Pennequin-Cardinal, A; Locoge, N; Galloo, J-C

    2008-04-01

    This study examined the performances of a thermal desorbable radial diffusive sampler for the weekly measurement of eight glycol ethers in indoor air and described the results of an application of this method carried out as part of HABIT'AIR Nord - Pas de Calais program for the air monitoring of these compounds in sixty homes located in northern France. The target compounds were the four glycol ethers banned from sale to the public in France since the 1990s (i.e. 2-methoxy ethanol, 2-ethoxy ethanol and their acetates) and four other glycol ethers derivatives of which the use have increased considerably (i.e. 1-methoxy-2-propanol, 2-butoxy ethanol and their acetates).A test program was carried out with the aim of validating the passive sampling method. It allowed the estimation of all the parameters of a method for each compound (calibration, analytical precision, desorption efficiency, sampling rate in standard conditions, detection limit and stability of sample before and after exposure), the examination of the influence of environmental factors on the sampling rate by some exposure chamber experiments and the assessment of the uncertainty of the measurements. The results of this evaluation demonstrated that the method has turned out to be suitable for six out of eight glycol ethers tested. The effect of the environmental factors on the sampling rates was the main source of measurement uncertainty. The measurements done in sixty homes revealed a relative abundance of 1-methoxy-2-propanol that was found in more than two thirds of homes at concentration levels of 4.5 microg m(-3) on average (a maximum value of 28 microg m(-3)). 1-methoxy-2-propanol acetate and 2-butoxy ethanol were also detected, but less frequently (in 19% of homes) and with the concentrations below 12 microg m(-3). The highest levels of these glycol ethers appear to be in relation to the emissions occurring at the time of cleaning tasks.

  18. [Volatile organic compounds (VOCs) emitted from wood furniture--estimation of emission rate by passive flux sampler].

    PubMed

    Jinno, Hideto; Tanaka-Kagawa, Toshiko; Furuta, Mitsuko; Shibatsuji, Masayoshi; Nishimura, Tetsuji

    2011-01-01

    The aim of this study was to evaluate aldehydes and other volatile organic compounds (VOCs) emission from furniture, which may cause hazardous influence on human being such as sick building/sick house syndrome. In this study, VOCs emitted from six kinds of wood furniture, including three set of dining tables and three beds, were analyzed by large chamber test method (JIS A 1911). Based on the emission rates of total VOCs (TVOC), the impacts on the indoor TVOC was estimated by the simulation model with volume of 20 m3 and ventilation frequency of 0.5 times/h. The estimated increment of formaldehyde were exceeded the guideline value (100 microg/m3) in one set of dining table and one bed. The estimated TVOC increment values were exceeded the provisional target value for indoor air (400 microg/m3) in two sets of dining tables and two beds. These results revealed that VOC emissions from wood furniture may influence significantly indoor air quality. Also, in this study, to establish the alternative method for large chamber test methods, emission rates from representative five areas of furniture unit were evaluated by passive sampling method using flux sampler and emission rate from full-sized furniture was predicted. Emission rates predicted by flux passive sampler were 10-106% (formaldehyde) and 8-141% (TVOC) of the data measured using large chamber test, respectively.

  19. 47 CFR Appendix B to Part 64 - Priority Access Service (PAS) for National Security and Emergency Preparedness (NSEP)

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Priority Access Service (PAS) for National.... 64, App. B Appendix B to Part 64—Priority Access Service (PAS) for National Security and Emergency... meaning as in Appendix A to Part 64: (a) Assignment; (b) Government; (c) National Communications...

  20. Does Faux Pas Detection in Adult Autism Reflect Differences in Social Cognition or Decision-Making Abilities?

    ERIC Educational Resources Information Center

    Thiébaut, Flora I.; White, Sarah J.; Walsh, Annabel; Klargaard, Solja K.; Wu, Hsuan-Chen; Rees, Geraint; Burgess, Paul W.

    2016-01-01

    43 typically-developed adults and 35 adults with ASD performed a cartoon faux pas test. Adults with ASD apparently over-detected faux pas despite good comprehension abilities, and were generally slower at responding. Signal detection analysis demonstrated that the ASD participants had significantly greater difficulty detecting whether a cartoon…

  1. Efficacy of a vacuum benthos sampler for collecting demersal fish eggs from gravel substratum

    USGS Publications Warehouse

    Ruetz, C. R.; Jennings, C.A.

    1997-01-01

    We used two densities of eggs (low=900 eggs/m2; high=5100 eggs/m2) in laboratory experiments to estimate the recovery efficiency of the Brown benthos sampler for collecting fish eggs from gravel substrate and to determine if differences (e.g., 5-fold) in egg density in the substratum could be detected with the sampler. The mean egg recovery efficiency of the sampler in the low and high density treatments was 30% (SE=8.7) and 35% (SE=3.8), respectively. The difference between the treatment means was not significant. Therefore, data from the two treatments were pooled and used to estimate the recovery efficiency of the sampler (32.7%, SE=4.4). However, we were able to detect a 5?? difference in the number of eggs collected with the sampler between the two treatments. Our estimate of the recovery efficiency of the sampler for collecting fish eggs was less than those reported for the sampler's efficiency for collecting benthic macroinvertebrates. The low recovery efficiency of the sampler for collecting fish eggs does not lessen the utility of the device. Rather, ecologists planning to use the sampler must estimate the recovery efficiency of target fauna, especially if density estimates are to be calculated, because recovery efficiency probably is less than 100%. ?? Munksgaard, 1997.

  2. Calibration of high flow rate thoracic-size selective samplers

    PubMed Central

    Lee, Taekhee; Thorpe, Andrew; Cauda, Emanuele; Harper, Martin

    2016-01-01

    High flow rate respirable size selective samplers, GK4.126 and FSP10 cyclones, were calibrated for thoracic-size selective sampling in two different laboratories. The National Institute for Occupational Safety and Health (NIOSH) utilized monodisperse ammonium fluorescein particles and scanning electron microscopy to determine the aerodynamic particle size of the monodisperse aerosol. Fluorescein intensity was measured to determine sampling efficiencies of the cyclones. The Health Safety and Laboratory (HSL) utilized a real time particle sizing instrument (Aerodynamic Particle Sizer) and poly-disperse glass sphere particles and particle size distributions between the cyclone and reference sampler were compared. Sampling efficiency of the cyclones were compared to the thoracic convention defined by the American Conference of Governmental Industrial Hygienists (ACGIH)/Comité Européen de Normalisation (CEN)/International Standards Organization (ISO). The GK4.126 cyclone showed minimum bias compared to the thoracic convention at flow rates of 3.5 l min−1 (NIOSH) and 2.7–3.3 l min−1 (HSL) and the difference may be from the use of different test systems. In order to collect the most dust and reduce the limit of detection, HSL suggested using the upper end in range (3.3 l min−1). A flow rate of 3.4 l min−1 would be a reasonable compromise, pending confirmation in other laboratories. The FSP10 cyclone showed minimum bias at the flow rate of 4.0 l min−1 in the NIOSH laboratory test. The high flow rate thoracic-size selective samplers might be used for higher sample mass collection in order to meet analytical limits of quantification. PMID:26891196

  3. Calibration of high flow rate thoracic-size selective samplers.

    PubMed

    Lee, Taekhee; Thorpe, Andrew; Cauda, Emanuele; Harper, Martin

    2016-01-01

    High flow rate respirable size selective samplers, GK4.126 and FSP10 cyclones, were calibrated for thoracic-size selective sampling in two different laboratories. The National Institute for Occupational Safety and Health (NIOSH) utilized monodisperse ammonium fluorescein particles and scanning electron microscopy to determine the aerodynamic particle size of the monodisperse aerosol. Fluorescein intensity was measured to determine sampling efficiencies of the cyclones. The Health Safety and Laboratory (HSL) utilized a real time particle sizing instrument (Aerodynamic Particle Sizer) and polydisperse glass sphere particles and particle size distributions between the cyclone and reference sampler were compared. Sampling efficiency of the cyclones were compared to the thoracic convention defined by the American Conference of Governmental Industrial Hygienists (ACGIH)/Comité Européen de Normalisation (CEN)/International Standards Organization (ISO). The GK4.126 cyclone showed minimum bias compared to the thoracic convention at flow rates of 3.5 l min(-1) (NIOSH) and 2.7-3.3 l min(-1) (HSL) and the difference may be from the use of different test systems. In order to collect the most dust and reduce the limit of detection, HSL suggested using the upper end in range (3.3 l min(-1)). A flow rate of 3.4 l min(-1) would be a reasonable compromise, pending confirmation in other laboratories. The FSP10 cyclone showed minimum bias at the flow rate of 4.0 l min(-1) in the NIOSH laboratory test. The high flow rate thoracic-size selective samplers might be used for higher sample mass collection in order to meet analytical limits of quantification. PMID:26891196

  4. Searching for planetary nebulae at the Galactic halo via J-PAS and J-PLUS

    NASA Astrophysics Data System (ADS)

    Goncalves, Denise R.; Aparício-Villegas, Teresa; Akras, Stavros; Borges Fernandes, Marcelo; J-PAS Collaboration

    2015-08-01

    The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow-band imaging, very wide field cosmological survey to be carried out from a dedicated 2.5m telescope and a 4.7 sq.deg camera with 1.2Gpix. It will last 5 years and will observe 8500 sq.deg of Northern sky to a 5-σ magnitude depth for point sources, equivalent to i ~23.3 over an aperture of 2 arcsec2. The J-PAS filter system consists of 54 contiguous narrow band filters of 145-Å FWHM, from 3,500 to 10,000Å. Two broad-band filters will be added at the extremes, UV and IR, plus 3 SDSS g, r, and i filters. The Javalambre Photometric Local Universe Survye (J-PLUS) will be an auxiliary survey ofJ-PAS (mainly for calibration) with a dedicated 0.80m telescope. J-PLUS comprises 12 filters, including g, r, i and z SDSS ones. Though about 2,500 planetary nebulae (PNe, confirmed spectroscopically) are known in the Galaxy, only 14 objects have been convincingly identified as halo PNe. They were classified as such from their location, kinematics and chemistry. Halo PNe are able to reveal precious information for the study of low- and intermediate-mass star evolution and the early chemical conditions of the Galaxy. The characteristic low continuum and intense line emissions of PNe make them good objects to be searched by J-PAS, and even by J-PLUS. For instance, the halo PNe BoBn 1, DdDm 1 and PS 1, located somewhere between 11 and 24 kpc from the Sun, have B magnitudes of 16, 14 and 13.4, respectively. Such values are easily encompassed by J-PAS/J-PLUS, given the typical limit magnitude of the survey. Though covering a significantly smaller sky area, data from the ALHAMBRA survey were used to test our J-PAS/J-PLUS strategy to search for PNe. Our first results will be shown in this poster.

  5. Energy storage considerations for a robotic Mars surface sampler

    NASA Technical Reports Server (NTRS)

    O'Donnell, P. M.; Cataldo, R. L.; Gonzalez-Sanabria, O. D.

    1988-01-01

    The characteristics of various energy storage systems (including Ni-Cd, Ni-H2, Ag-Zn, Li-XS, Na-S, PbSO4, and regenerative fuel cell systems) considered for a robotic Mars surface sampler are reviewed. It is concluded that the bipolar nickel-hydrogen battery and the sodium-sulfur battery are both viable candidates as storage systems for the rover's Radioisotope Thermoelectric Generator. For a photovoltaic storage system, the regenerative fuel cell and the bipolar nickel-hydrogen battery are the primary candidates.

  6. Guidelines for the use of the semipermeable membrane device (SPMD) and the polar organic chemical integrative sampler (POCIS) in environmental monitoring studies

    USGS Publications Warehouse

    Alvarez, David A.

    2010-01-01

    The success of an environmental monitoring study using passive samplers, or any sampling method, begins in the office or laboratory. Regardless of the specific methods used, the general steps include the formulation of a sampling plan, training of personnel, performing the field (sampling) work, processing the collected samples to recover chemicals of interest, analysis of the enriched extracts, and interpretation of the data. Each of these areas will be discussed in the following sections with emphasis on specific considerations with the use of passive samplers. Water is an extremely heterogeneous matrix both spatially and temporally (Keith, 1991). The mixing and distribution of dissolved organic chemicals in a water body are controlled by the hydrodynamics of the water, the sorption partition coefficients of the chemicals, and the amount of organic matter (suspended sediments, colloids, and dissolved organic carbon) present. In lakes and oceans, stratification because of changes in temperature, water movement, and water composition can occur resulting in dramatic changes in chemical concentrations with depth (Keith, 1991). Additional complications related to episodic events, such as surface runoff, spills, and other point source contamination, can result in isolated or short-lived pulses of contaminants in the water. The application of passive sampling technologies for the monitoring of legacy and emerging organic chemicals in the environment is becoming widely accepted worldwide. The primary use of passive sampling methods for environmental studies is in the area of surface-water monitoring; however, these techniques have been applied to air and groundwater monitoring studies. Although these samplers have no mechanical or moving parts, electrical or fuel needs which require regular monitoring, there are still considerations that need to be understood in order to have a successful study. Two of the most commonly used passive samplers for organic contaminants are

  7. Crystal structure of the Alpha subunit PAS domain from soluble guanylyl cyclase

    PubMed Central

    Purohit, Rahul; Weichsel, Andrzej; Montfort, William R

    2013-01-01

    Soluble guanylate cyclase (sGC) is a heterodimeric heme protein of ∼150 kDa and the primary nitric oxide receptor. Binding of NO stimulates cyclase activity, leading to regulation of cardiovascular physiology and providing attractive opportunities for drug discovery. How sGC is stimulated and where candidate drugs bind remains unknown. The α and β sGC chains are each composed of Heme-Nitric Oxide Oxygen (H-NOX), Per-ARNT-Sim (PAS), coiled-coil and cyclase domains. Here, we present the crystal structure of the α1 PAS domain to 1.8 Å resolution. The structure reveals the binding surfaces of importance to heterodimer function, particularly with respect to regulating NO binding to heme in the β1 H-NOX domain. It also reveals a small internal cavity that may serve to bind ligands or participate in signal transduction. PMID:23934793

  8. Queer paradox/paradoxical queer: Anne Garréta's Pas un jour (2002).

    PubMed

    Cairns, Lucille

    2007-01-01

    This paper shows how Anne Garréta's Pas un jour (2002) is a decidedly queer text, in both the new and the old sense of that contested epithet. I examine three interrelated concerns central to Pas un jour. First, I analyze Garréta's mediation of desire in general: her own experiences of it; modalities thereof which subvert more 'normative' models of lesbianism; and her convergences with other gay, but male writers and theorists of desire such as Guy Hocquenghem, Gilles Deleuze and Michel Foucault. Second, I interrogate Garréta's dichotomy between desire and friendship, and adumbrate contrasts with Foucauldian theory. Finally, I scrutinize the meaning and value attributed to the particular body of desire with which Garréta is most commonly associated-homosexuality- and their links with those of a contemporary gay male writer, Dominique Fernandez. PMID:17804371

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

    PubMed

    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.

  10. Practical Analysis of materials with depth varying compositions using FT-IR photoacoustic spectroscopy (PAS)

    SciTech Connect

    J.F. McClelland; R.W. Jones; Siquan Luo

    2004-09-30

    FT-IR photoacoustic spectroscopy (PAS) is discussed as a nondestructive method to probe the molecular composition of materials versus depth on the basis of the analysis of layers of experimentally controllable thickness, which are measured from the sample surface to depths of some tens of micrometers, depending on optical and thermal properties. Computational methods are described to process photoacoustic amplitude and phase spectra for both semi-quantitative and quantitative depth analyses. These methods are demonstrated on layered and gradient samples.

  11. Equilibration times, compound selectivity, and stability of diffusion samplers for collection of ground-water VOC concentrations

    USGS Publications Warehouse

    Vroblesky, D.A.; Campbell, T.R.

    2001-01-01

    Vapor-filled polyethylene diffusion samplers (typically used to locate discharge zones of volatile organic compound contaminated ground water beneath streams and lakes) and water-filled polyethylene diffusion bag samplers (typically used to obtain volatile organic compound concentrations in ground-water at wells) were tested to determine compound selectivity, equilibration times, and sample stability. The aqueous concentrations of several volatile organic compounds obtained from within water-filled diffusion samplers closely matched concentrations in ambient water outside the samplers. An exception was methyl-tert-butyl ether, which was detectable, but not reliably quantifiable using the diffusion samplers. The samplers equilibrated to a variety of volatile organic compounds within 24 h for vapor-filled passive diffusion vial samplers and within 48 h for water-filled passive diffusion bag samplers. Under field conditions, however, a longer equilibration time may be required to account for environmental disturbances caused by sampler deployment. An equilibrium period for both vapor- and water-filled diffusion samplers of approximately 2 weeks probably is adequate for most investigations in sandy formations. Longer times may be required for diffusion-sampler equilibration in poorly permeable sediment. The vapor-filled samplers should be capped and water from the diffusion bag samplers should be transferred to sampling vials immediately upon recovery to avoid volatilization losses of the gasses. ?? 2001 Elsevier Science Ltd.

  12. A cell cycle kinase with tandem sensory PAS domains integrates cell fate cues

    PubMed Central

    Mann, Thomas H.; Seth Childers, W.; Blair, Jimmy A.; Eckart, Michael R.; Shapiro, Lucy

    2016-01-01

    All cells must integrate sensory information to coordinate developmental events in space and time. The bacterium Caulobacter crescentus uses two-component phospho-signalling to regulate spatially distinct cell cycle events through the master regulator CtrA. Here, we report that CckA, the histidine kinase upstream of CtrA, employs a tandem-PAS domain sensor to integrate two distinct spatiotemporal signals. Using CckA reconstituted on liposomes, we show that one PAS domain modulates kinase activity in a CckA density-dependent manner, mimicking the stimulation of CckA kinase activity that occurs on its transition from diffuse to densely packed at the cell poles. The second PAS domain interacts with the asymmetrically partitioned second messenger cyclic-di-GMP, inhibiting kinase activity while stimulating phosphatase activity, consistent with the selective inactivation of CtrA in the incipient stalked cell compartment. The integration of these spatially and temporally regulated signalling events within a single signalling receptor enables robust orchestration of cell-type-specific gene regulation. PMID:27117914

  13. Noninvasive glucose sensing in scattering media using OCT, PAS, and TOF techniques

    NASA Astrophysics Data System (ADS)

    Alarousu, Erkki; Hast, Jukka T.; Kinnunen, Matti T.; Kirillin, Mikhail Y.; Myllyla, Risto A.; Plucinski, Jerzy; Popov, Alexey P.; Priezzhev, Alexander V.; Prykari, Tuukka; Saarela, Juha; Zhao, Zuomin

    2004-08-01

    In this paper, optical measurement techniques, which enable non-invasive measurement, are superimposed to glucose sensing in scattering media. Used measurement techniques are Optical Coherence Tomography (OCT), Photoacoustic spectroscopy (PAS) and laser pulse Time-of-Flight (TOF) measurement using a streak camera. In parallel with measurements, a Monte-Carlo (MC) simulation models have been developed. Experimental in vitro measurements were performed using Intralipid fat emulsion as a tissue simulating phantom for OCT and TOF measurements. In PAS measurements, a pork meat was used as a subject but also preliminary in vivo measurements were done. OCT measurement results show that the slope of the OCT signal's envelope changes as a function of glucose content in the scattering media. TOF measurements show that the laser pulse full width of half maximum (FWHM) changes a little as function of glucose content. An agreement with MC-simulations and measurements with Intralipid was also found. Measurement results of PAS technique show that changes in glucose content in the pork meat tissue can be measured. In vivo measurements with a human volunteer show that other factors such as physiological change, blood circulation and body temperature drift may interfere the PA response of glucose.

  14. Laser diode bars based on strain-compensated AlGaPAs/GaAs heterostructures

    SciTech Connect

    Marmalyuk, Aleksandr A; Ladugin, M A; Yarotskaya, I V; Panarin, V A; Mikaelyan, G T

    2012-01-31

    Traditional (in the AlGaAs/GaAs system) and phosphorus-compensated (in the AlGaAs/AlGaPAs/GaAs system) laser heterostructures emitting at a wavelength of 850 nm are grown by MOVPE and studied. Laser diode bars are fabricated and their output characteristics are studied. The method used to grow heterolayers allowed us to control (minimise) mechanical stresses in the AlGaPAs/GaAs laser heterostructure, which made it possible to keep its curvature at the level of the initial curvature of the substrate. It is shown that the use of a compensated AlGaPAs/GaAs heterostructure improves the linear distribution of emitting elements in the near field of laser diode arrays and allows the power - current characteristic to retain its slope at high pump currents owing to a uniform contact of all emitting elements with the heat sink. The radius of curvature of the grown compensated heterostructures turns out to be smaller than that of traditional heterostructures.

  15. Principles of Ligand Binding within a Completely Buried Cavity in HIF2[alpha] PAS-B

    SciTech Connect

    Key, Jason; Scheuermann, Thomas H.; Anderson, Peter C.; Daggett, Valerie; Gardner, Kevin H.

    2010-04-19

    Hypoxia-inducible factors (HIFs) are heterodimeric transcription factors responsible for the metazoan hypoxia response and promote tumor growth, metastasis, and resistance to cancer treatment. The C-terminal Per-ARNT-Sim (PAS) domain of HIF2{alpha} (HIF2{alpha} PAS-B) contains a preformed solvent-inaccessible cavity that binds artificial ligands that allosterically perturb the formation of the HIF heterodimer. To better understand how small molecules bind within this domain, we examined the structures and equilibrium and transition-state thermodynamics of HIF2{alpha} PAS-B with several artificial ligands using isothermal titration calorimetry, NMR exchange spectroscopy, and X-ray crystallography. Rapid association rates reveal that ligand binding is not dependent upon a slow conformational change in the protein to permit ligand access, despite the closed conformation observed in the NMR and crystal structures. Compensating enthalpic and entropic contributions to the thermodynamic barrier for ligand binding suggest a binding-competent transition state characterized by increased structural disorder. Finally, molecular dynamics simulations reveal conversion between open and closed conformations of the protein and pathways of ligand entry into the binding pocket.

  16. [Parental alienation syndrome (PAS): unknown in medical settings, endemic in courts].

    PubMed

    Pignotti, Maria Serenella

    2013-02-01

    A purposed syndrome of so-called parental alienation (PAS), unsupported by any evidence-based data, unknown in medical settings, unquoted in medical books, absent in DSM and ICD, never demonstrated by controlled studies published in high scientific level journals, is rampant in Courts where it can lead to loose parental custody. During a divorce trial, almost always the mothers and the children, become joint in a sort of folie au deux, in a denigration campaign of ex-husband/father. From a review on this issue it seems evident its theoretical roots lie on a theory that justify gender violence and children sexual abuse. The bias that both of them are layers and that he children have not autonomy block their possibility of any defence in front of a Court. In severe cases, PAS becomes a new and efficient tool of intra-familiar violence. The treatment of severe cases is to stop any contact between mother and children. The resort to PAS in Courts must be strongly rejected.

  17. [Parental alienation syndrome (PAS): unknown in medical settings, endemic in courts].

    PubMed

    Pignotti, Maria Serenella

    2013-02-01

    A purposed syndrome of so-called parental alienation (PAS), unsupported by any evidence-based data, unknown in medical settings, unquoted in medical books, absent in DSM and ICD, never demonstrated by controlled studies published in high scientific level journals, is rampant in Courts where it can lead to loose parental custody. During a divorce trial, almost always the mothers and the children, become joint in a sort of folie au deux, in a denigration campaign of ex-husband/father. From a review on this issue it seems evident its theoretical roots lie on a theory that justify gender violence and children sexual abuse. The bias that both of them are layers and that he children have not autonomy block their possibility of any defence in front of a Court. In severe cases, PAS becomes a new and efficient tool of intra-familiar violence. The treatment of severe cases is to stop any contact between mother and children. The resort to PAS in Courts must be strongly rejected. PMID:23535957

  18. Role of the PAS Sensor Domains in the Bacillus subtilis Sporulation Kinase KinA

    PubMed Central

    Winnen, Brit; Anderson, Eric; Cole, James L.; King, Glenn F.

    2013-01-01

    Histidine kinases are sophisticated molecular sensors that are used by bacteria to detect and respond to a multitude of environmental signals. KinA is the major histidine kinase required for initiation of sporulation upon nutrient deprivation in Bacillus subtilis. KinA has a large N-terminal region (residues 1 to 382) that is uniquely composed of three tandem Per-ARNT-Sim (PAS) domains that have been proposed to constitute a sensor module. To further enhance our understanding of this “sensor” region, we defined the boundaries that give rise to the minimal autonomously folded PAS domains and analyzed their homo- and heteroassociation properties using analytical ultracentrifugation, nuclear magnetic resonance (NMR) spectroscopy, and multiangle laser light scattering. We show that PASA self-associates very weakly, while PASC is primarily a monomer. In contrast, PASB forms a stable dimer (Kd [dissociation constant] of <10 nM), and it appears to be the main N-terminal determinant of KinA dimerization. Analysis of KinA mutants deficient for one or more PAS domains revealed a critical role for PASB, but not PASA, in autophosphorylation of KinA. Our findings suggest that dimerization of PASB is important for keeping the catalytic domain of KinA in a functional conformation. We use this information to propose a model for the structure of the N-terminal sensor module of KinA. PMID:23504013

  19. A Study on N2O Measurement Characteristics Using Photoacoustic Spectroscopy (PAS)

    PubMed Central

    Kang, Soyoung; Kim, Seoungjin; Kang, Seongmin; Lee, Jeongwoo; Cho, Chang-Sang; Sa, Jea-Hwan; Jeon, Eui-Chan

    2014-01-01

    N2O, which is emitted mainly from nitrogen decomposition via bacteria, livestock manure, agricultural fertilizer use, fossil fuel combustion and waste incineration, is classified as a substance that causes significant destruction of the ozone layer. The N2O measurement methods for these emission sources may be divided into chromatography, optical, and electrical current measurements. Chromatography has been widely utilized for analyzing N2O. However, up until now, few studies have been conducted on N2O using photoacoustic spectroscopy. Therefore, this study aimed to evaluate performance of photoacoustic spectroscopy in this regard based on laboratory and field test results. The repeatability of photoacoustic spectroscopy was measured at 1.12%, which is lower than the repeatability of 3.0% suggested by the ISO 1564 standard, so, it has shown an excellent repeatability. The detection limit was determined to be 0.025 ppm, and the response time was confirmed to be 3 min and 26 s. The results of comparison between these measurements and GC show that the latter has superior accuracy, but mobility and convenience are superior for PAS. On the contrary, GC has a continuous measurement limitation, but PAS makes it possible to conduct continuous measurements. Therefore, PAS can be extremely useful to confirm the characteristics of N2O emissions and to quantify their amount. PMID:25106022

  20. A study on N2O measurement characteristics using photoacoustic spectroscopy (PAS).

    PubMed

    Kang, Soyoung; Kim, Seoungjin; Kang, Seongmin; Lee, Jeongwoo; Cho, Chang-Sang; Sa, Jea-Hwan; Jeon, Eui-Chan

    2014-01-01

    N2O, which is emitted mainly from nitrogen decomposition via bacteria, livestock manure, agricultural fertilizer use, fossil fuel combustion and waste incineration, is classified as a substance that causes significant destruction of the ozone layer. The N2O measurement methods for these emission sources may be divided into chromatography, optical, and electrical current measurements. Chromatography has been widely utilized for analyzing N2O. However, up until now, few studies have been conducted on N2O using photoacoustic spectroscopy. Therefore, this study aimed to evaluate performance of photoacoustic spectroscopy in this regard based on laboratory and field test results. The repeatability of photoacoustic spectroscopy was measured at 1.12%, which is lower than the repeatability of 3.0% suggested by the ISO 1564 standard, so, it has shown an excellent repeatability. The detection limit was determined to be 0.025 ppm, and the response time was confirmed to be 3 min and 26 s. The results of comparison between these measurements and GC show that the latter has superior accuracy, but mobility and convenience are superior for PAS. On the contrary, GC has a continuous measurement limitation, but PAS makes it possible to conduct continuous measurements. Therefore, PAS can be extremely useful to confirm the characteristics of N2O emissions and to quantify their amount.

  1. Gradient-based MCMC samplers for dynamic causal modelling

    PubMed Central

    Sengupta, Biswa; Friston, Karl J.; Penny, Will D.

    2016-01-01

    In this technical note, we derive two MCMC (Markov chain Monte Carlo) samplers for dynamic causal models (DCMs). Specifically, we use (a) Hamiltonian MCMC (HMC-E) where sampling is simulated using Hamilton’s equation of motion and (b) Langevin Monte Carlo algorithm (LMC-R and LMC-E) that simulates the Langevin diffusion of samples using gradients either on a Euclidean (E) or on a Riemannian (R) manifold. While LMC-R requires minimal tuning, the implementation of HMC-E is heavily dependent on its tuning parameters. These parameters are therefore optimised by learning a Gaussian process model of the time-normalised sample correlation matrix. This allows one to formulate an objective function that balances tuning parameter exploration and exploitation, furnishing an intervention-free inference scheme. Using neural mass models (NMMs)—a class of biophysically motivated DCMs—we find that HMC-E is statistically more efficient than LMC-R (with a Riemannian metric); yet both gradient-based samplers are far superior to the random walk Metropolis algorithm, which proves inadequate to steer away from dynamical instability. PMID:26213349

  2. Gradient-based MCMC samplers for dynamic causal modelling.

    PubMed

    Sengupta, Biswa; Friston, Karl J; Penny, Will D

    2016-01-15

    In this technical note, we derive two MCMC (Markov chain Monte Carlo) samplers for dynamic causal models (DCMs). Specifically, we use (a) Hamiltonian MCMC (HMC-E) where sampling is simulated using Hamilton's equation of motion and (b) Langevin Monte Carlo algorithm (LMC-R and LMC-E) that simulates the Langevin diffusion of samples using gradients either on a Euclidean (E) or on a Riemannian (R) manifold. While LMC-R requires minimal tuning, the implementation of HMC-E is heavily dependent on its tuning parameters. These parameters are therefore optimised by learning a Gaussian process model of the time-normalised sample correlation matrix. This allows one to formulate an objective function that balances tuning parameter exploration and exploitation, furnishing an intervention-free inference scheme. Using neural mass models (NMMs)-a class of biophysically motivated DCMs-we find that HMC-E is statistically more efficient than LMC-R (with a Riemannian metric); yet both gradient-based samplers are far superior to the random walk Metropolis algorithm, which proves inadequate to steer away from dynamical instability.

  3. Gradient-based MCMC samplers for dynamic causal modelling.

    PubMed

    Sengupta, Biswa; Friston, Karl J; Penny, Will D

    2016-01-15

    In this technical note, we derive two MCMC (Markov chain Monte Carlo) samplers for dynamic causal models (DCMs). Specifically, we use (a) Hamiltonian MCMC (HMC-E) where sampling is simulated using Hamilton's equation of motion and (b) Langevin Monte Carlo algorithm (LMC-R and LMC-E) that simulates the Langevin diffusion of samples using gradients either on a Euclidean (E) or on a Riemannian (R) manifold. While LMC-R requires minimal tuning, the implementation of HMC-E is heavily dependent on its tuning parameters. These parameters are therefore optimised by learning a Gaussian process model of the time-normalised sample correlation matrix. This allows one to formulate an objective function that balances tuning parameter exploration and exploitation, furnishing an intervention-free inference scheme. Using neural mass models (NMMs)-a class of biophysically motivated DCMs-we find that HMC-E is statistically more efficient than LMC-R (with a Riemannian metric); yet both gradient-based samplers are far superior to the random walk Metropolis algorithm, which proves inadequate to steer away from dynamical instability. PMID:26213349

  4. Enhancement of hERG channel activity by scFv antibody fragments targeted to the PAS domain.

    PubMed

    Harley, Carol A; Starek, Greg; Jones, David K; Fernandes, Andreia S; Robertson, Gail A; Morais-Cabral, João H

    2016-08-30

    The human human ether-à-go-go-related gene (hERG) potassium channel plays a critical role in the repolarization of the cardiac action potential. Changes in hERG channel function underlie long QT syndrome (LQTS) and are associated with cardiac arrhythmias and sudden death. A striking feature of this channel and KCNH channels in general is the presence of an N-terminal Per-Arnt-Sim (PAS) domain. In other proteins, PAS domains bind ligands and modulate effector domains. However, the PAS domains of KCNH channels are orphan receptors. We have uncovered a family of positive modulators of hERG that specifically bind to the PAS domain. We generated two single-chain variable fragments (scFvs) that recognize different epitopes on the PAS domain. Both antibodies increase the rate of deactivation but have different effects on channel activation and inactivation. Importantly, we show that both antibodies, on binding to the PAS domain, increase the total amount of current that permeates the channel during a ventricular action potential and significantly reduce the action potential duration recorded in human cardiomyocytes. Overall, these molecules constitute a previously unidentified class of positive modulators and establish that allosteric modulation of hERG channel function through ligand binding to the PAS domain can be attained. PMID:27516548

  5. 50 CFR 260.50 - Suspension or revocation of license of licensed sampler or licensed inspector.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Suspension or revocation of license of... Licensing of Samplers and Inspectors § 260.50 Suspension or revocation of license of licensed sampler or... or evidence that he may wish to offer as to why his license should not be suspended or revoked....

  6. Quantitating the efficiency of the coal mine personal respirable dust sampler for sampling oxide fumes.

    PubMed

    Tomb, T F; Beckert, A J; Treaftis, H N

    1976-08-01

    Coal mine environments containing fume contaminants are assessed using the standard personal respirable dust sampler. The effect of the first-stage collector and filter on the total concentration measured was evaluated. The results showed that the personal respirable dust sampler could be used to sample fumes with TLV's greater than 1.0 mg/m3.

  7. Comparison of continuous monitor (TEOM) and gravimetric sampler particulate matter concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Tapered Element Oscillating Microbalance (TEOM) sampler is an EPA designated equivalent method sampler for measuring PM10 concentrations. PM10 refers to the mass fraction of particulate matter suspended in the atmosphere having a nominal aerodynamic diameter less than or equal to 10 micrometers ...

  8. Guidelines for Using Passive Samplers to Monitor Organic Contaminants at Superfund Sediment Sites

    EPA Science Inventory

    Passive samplers are monitoring tools that can provide faster, cheaper, and scientifically-sound information about the water column and interstitial water concentrations of contaminants of concern (COC) at Superfund sites. Often, the use of passive samplers is more effective tha...

  9. An Application of Passive Samplers to Understand Atmospheric Mercury Concentration and Dry Deposition Spatial Distributions

    EPA Science Inventory

    Two modified passive samplers were evaluated at multiple field locations. The sampling rate (SR) of the modified polyurethane foam (PUF)-disk passive sampler for total gaseous mercury (TGM) using gold-coated quartz fiber filters (GcQFF) and gaseous oxidized mercury (GOM) using io...

  10. Development and field validation of a new diffusive sampler for determination of atmospheric volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Özden Üzmez, Özlem; Gaga, Eftade O.; Döğeroğlu, Tuncay

    2015-04-01

    A tailor-made diffusive sampler was developed for the determination of atmospheric Volatile Organic Compounds (VOCs) and the validation of the sampler was carried out under field conditions. All parts of the diffusive sampler which are reusable after a proper cleaning process were made of plastic material (delrin). The reusability of the sampler brings an important advantage considering its lower cost. Activated carbon was used as adsorbent and VOCs adsorbed on the activated carbon were analyzed by GC-MS (gas chromatography equipped with mass selective detector). A comprehensive validation study including detection limit, precision, bias, recovery, self-consistency, shelf life, storage stability, reusability was carried out in accordance with the related European standards ((EN) 13528-1 (2000) and 13528-2 (2000)). Also, a comparison was performed with some commercial diffusive samplers such as 3 M OVM 3500 and Radiello to test the performance of the new diffusive sampler in different environments such as urban area and road tunnel. Uptake rates for the measured VOCs were determined and they were evaluated together with the meteorological parameters (temperature, humidity, wind speed). According to the validation results; all the parameters evaluated for the sampler comply with the related standards and this is an indication of the reliability of the sampler for the sampling of VOCs in the atmosphere.

  11. 40 CFR 53.54 - Test for proper sampler operation following power interruptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... sampler) and download all archived instrument data from the test sampler. (f) Test results. At the... minutes. (4) Flow measurement adaptor (40 CFR part 50, appendix L, figure L-30) or equivalent adaptor to... the flow path near the filter. (6) Teflon sample filter, as specified in section 6 of 40 CFR part...

  12. 40 CFR 53.54 - Test for proper sampler operation following power interruptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... sampler) and download all archived instrument data from the test sampler. (f) Test results. At the... minutes. (4) Flow measurement adaptor (40 CFR part 50, appendix L, figure L-30) or equivalent adaptor to... the flow path near the filter. (6) Teflon sample filter, as specified in section 6 of 40 CFR part...

  13. 40 CFR 53.54 - Test for proper sampler operation following power interruptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... sampler) and download all archived instrument data from the test sampler. (f) Test results. At the... minutes. (4) Flow measurement adaptor (40 CFR part 50, appendix L, figure L-30) or equivalent adaptor to... the flow path near the filter. (6) Teflon sample filter, as specified in section 6 of 40 CFR part...

  14. Assembly, operation and disassembly manual for the Battelle Large Volume Water Sampler (BLVWS)

    SciTech Connect

    Thomas, V.W.; Campbell, R.M.

    1984-12-01

    Assembly, operation and disassembly of the Battelle Large Volume Water Sampler (BLVWS) are described in detail. Step by step instructions of assembly, general operation and disassembly are provided to allow an operator completely unfamiliar with the sampler to successfully apply the BLVWS to his research sampling needs. The sampler permits concentration of both particulate and dissolved radionuclides from large volumes of ocean and fresh water. The water sample passes through a filtration section for particle removal then through sorption or ion exchange beds where species of interest are removed. The sampler components which contact the water being sampled are constructed of polyvinylchloride (PVC). The sampler has been successfully applied to many sampling needs over the past fifteen years. 9 references, 8 figures.

  15. Evaluation of workplace air monitoring locations

    SciTech Connect

    Stoetzel, G.A.; Cicotte, G.R.; Lynch, T.P. ); Aldrich, L.K. )

    1991-10-01

    Current federal guidance on occupational radiation protection recognizes the importance of conducting air flow studies to assist in the placement of air sampling and monitoring equipment. In support of this, Pacific Northwest Laboratory has provided technical assistance to Westinghouse Hanford Company for the purpose of evaluating the adequacy of air sampling and monitoring locations at selected Hanford facilities. Qualitative air flow studies were performed using smoke aerosols to visually determine air movement. Three examples are provided of how air flow studies results, along with information on the purpose of the air sample being collected, were used as a guide in placing the air samplers and monitors. Preparatory steps in conducting an air flow study should include: (1) identifying type of work performed in the work area including any actual or potential release points; (2) determining the amounts of radioactive material available for release and its chemical and physical form; (3) obtaining accurate work area descriptions and diagrams; (4) identifying the location of existing air samplers and monitors; (5) documenting physical and ventilation configurations; (6) notifying appropriate staff of the test; and (7) obtaining necessary equipment and supplies. The primary steps in conducting an air flow study are measurements of air velocities in the work area, release of the smoke aerosol at selected locations in the work area and the observation of air flow patterns, and finally evaluation and documentation of the results. 2 refs., 3 figs.

  16. A PAS domain with an oxygen labile [4Fe-4S](2+) cluster in the oxygen sensor kinase NreB of Staphylococcus carnosus.

    PubMed

    Müllner, Martin; Hammel, Oliver; Mienert, Bernd; Schlag, Steffen; Bill, Eckhard; Unden, Gottfried

    2008-12-30

    The cytoplasmic histidine sensor kinase NreB of Staphylococcus carnosus responds to O(2) and controls together with the response regulator NreC the expression of genes of nitrate/nitrite respiration. nreBC homologous genes were found in Staphylococcus strains and Bacillus clausii, and a modified form was found in some Lactobacillus strains. NreB contains a sensory domain with similarity to heme B binding PAS domains. Anaerobically prepared NreB of S. carnosus exhibited a (diamagnetic) [4Fe-4S](2+) cluster when assessed by Mossbauer spectroscopy. Upon reaction with air, the cluster was degraded with a half-life of approximately 2.5 min. No significant amounts of Mossbauer or EPR detectable intermediates were found during the decay, but magnetic Mossbauer spectra revealed formation of diamagnetic [2Fe-2S](2+) clusters. After extended exposure to air, NreB was devoid of a FeS cluster. Photoreduction with deazaflavin produced small amounts of [4Fe-4S](+), which were degraded subsequently. The magnetically perturbed Mossbauer spectrum of the [4Fe-4S](2+) cluster corroborated the S = 0 spin state and revealed uniform electric field gradient tensors of the iron sites, suggesting full delocalization of the valence electrons and binding of each of the Fe ions by four S ligands, including the ligand to the protein. Mutation of each of the four Cys residues inactivated NreB function in vivo in accordance with their role as ligands. [4Fe-4S](2+) cluster-containing NreB had high kinase activity. Exposure to air decreased the kinase activity and content of the [4Fe-4S](2+) cluster with similar half-lives. We conclude that the sensory domain of NreB represents a new type of PAS domain containing a [4Fe-4S](2+) cluster for sensing and function. PMID:19102705

  17. SAVANNAH RIVER SITE TANK 18 AND TANK 19 WALL SAMPLER PERFORMANCE

    SciTech Connect

    Leishear, R.; Thaxton, D.; Minichan, R.; France, T.; Steeper, T.; Corbett, J.; Martin, B.; Vetsch, B.

    2009-12-19

    A sampling tool was required to evaluate residual activity ({mu}Curies per square foot) on the inner wall surfaces of underground nuclear waste storage tanks. The tool was required to collect a small sample from the 3/8 inch thick tank walls. This paper documents the design, testing, and deployment of the remotely operated sampling device. The sampler provides material from a known surface area to estimate the overall surface contamination in the tank prior to closure. The sampler consisted of a sampler and mast assembly mast assembly, control system, and the sampler, or end effector, which is defined as the operating component of a robotic arm. The mast assembly consisted of a vertical 30 feet long, 3 inch by 3 inch, vertical steel mast and a cantilevered arm hinged at the bottom of the mast and lowered by cable to align the attached sampler to the wall. The sampler and mast assembly were raised and lowered through an opening in the tank tops, called a riser. The sampler is constructed of a mounting plate, a drill, springs to provide a drive force to the drill, a removable sampler head to collect the sample, a vacuum pump to draw the sample from the drill to a filter, and controls to operate the system. Once the sampler was positioned near the wall, electromagnets attached it to the wall, and the control system was operated to turn on the drill and vacuum to remove and collect a sample from the wall. Samples were collected on filters in removable sampler heads, which were readily transported for further laboratory testing.

  18. Silica Measurement with High Flow Rate Respirable Size Selective Samplers: A Field Study.

    PubMed

    Lee, Taekhee; Harper, Martin; Kashon, Michael; Lee, Larry A; Healy, Catherine B; Coggins, Marie A; Susi, Pam; O'Brien, Andrew

    2016-04-01

    High and low flow rate respirable size selective samplers including the CIP10-R (10 l min(-1)), FSP10 (11.2 l min(-1)), GK2.69 (4.4 l min(-1)), 10-mm nylon (1.7 l min(-1)), and Higgins-Dewell type (2.2 l min(-1)) were compared via side-by-side sampling in workplaces for respirable crystalline silica measurement. Sampling was conducted at eight different occupational sites in the USA and five different stonemasonry sites in Ireland. A total of 536 (268 pairs) personal samples and 55 area samples were collected. Gravimetric analysis was used to determine respirable dust mass and X-ray diffraction analysis was used to determine quartz mass. Ratios of respirable dust mass concentration, quartz mass concentration, respirable dust mass, and quartz mass from high and low flow rate samplers were compared. In general, samplers did not show significant differences greater than 30% in respirable dust mass concentration and quartz mass concentration when outliers (ratio <0.3 or >3.0) were removed from the analysis. The frequency of samples above the limit of detection and limit of quantification of quartz was significantly higher for the CIP10-R and FSP10 samplers compared to low flow rate samplers, while the GK2.69 cyclone did not show significant difference from low flow rate samplers. High flow rate samplers collected significantly more respirable dust and quartz than low flow rate samplers as expected indicating that utilizing high flow rate samplers might improve precision in quartz measurement. Although the samplers did not show significant differences in respirable dust and quartz concentrations, other practical attributes might make them more or less suitable for personal sampling.

  19. Silica Measurement with High Flow Rate Respirable Size Selective Samplers: A Field Study

    PubMed Central

    Lee, Taekhee; Harper, Martin; Kashon, Michael; Lee, Larry A.; Healy, Catherine B.; Coggins, Marie A.; Susi, Pam; O’Brien, Andrew

    2016-01-01

    High and low flow rate respirable size selective samplers including the CIP10-R (10 l min−1), FSP10 (11.2 l min−1), GK2.69 (4.4 l min−1), 10-mm nylon (1.7 l min−1), and Higgins-Dewell type (2.2 l min−1) were compared via side-by-side sampling in workplaces for respirable crystalline silica measurement. Sampling was conducted at eight different occupational sites in the USA and five different stonemasonry sites in Ireland. A total of 536 (268 pairs) personal samples and 55 area samples were collected. Gravimetric analysis was used to determine respirable dust mass and X-ray diffraction analysis was used to determine quartz mass. Ratios of respirable dust mass concentration, quartz mass concentration, respirable dust mass, and quartz mass from high and low flow rate samplers were compared. In general, samplers did not show significant differences greater than 30% in respirable dust mass concentration and quartz mass concentration when outliers (ratio <0.3 or >3.0) were removed from the analysis. The frequency of samples above the limit of detection and limit of quantification of quartz was significantly higher for the CIP10-R and FSP10 samplers compared to low flow rate samplers, while the GK2.69 cyclone did not show significant difference from low flow rate samplers. High flow rate samplers collected significantly more respirable dust and quartz than low flow rate samplers as expected indicating that utilizing high flow rate samplers might improve precision in quartz measurement. Although the samplers did not show significant differences in respirable dust and quartz concentrations, other practical attributes might make them more or less suitable for personal sampling. PMID:26608952

  20. Field comparison of air sampling methods for monomeric and polymeric 1,6-hexamethylene diisocyanate.

    PubMed

    Thomasen, Jennifer M; Fent, Kenneth W; Reeb-Whitaker, Carolyn; Whittaker, Stephen G; Nylander-French, Leena A

    2011-03-01

    This study was to critically compared 13 different air samplers for their ability to monitor air exposures to monomeric and polymeric 1,6-hexamethylene diisocyanate (HDI) in the automotive refinishing industry. Using both fast- and slow-drying clearcoat, we tested the following types of samplers: single- and dual-stage 37-mm polypropylene (PP) and polystyrene (PS) samplers (open- and closed-face), IOM (with plastic and stainless steel inserts), OSHA42, IsoChek, and WA-DOSH samplers. Midget impingers with frit were used as reference samplers. We observed the PP, PS, and IOM samplers to measure greater levels of HDI monomer and biuret when a fast-drying clearcoat was applied compared with a slow-drying clearcoat. When a slow-drying clearcoat was applied, the open-face PP and PS samplers measured significantly more monomeric and polymeric HDI (2-fold; p < 0.003) than the closed-face PP and PS samplers. We determined that significantly more monomeric and polymeric HDI were measured by impingers (1.3-1.9-fold) compared with single-stage PP/PS (N = 59), dual-stage PP/PS (N = 59), or IOM (N = 24) samplers. However, when stratified by cassette characteristics, the open-face single-stage PP and PS samplers performed equally to the impingers for HDI monomer when a fast-drying clearcoat was applied, and for all analytes when a slow-drying clearcoat was applied. Significantly higher HDI monomer concentrations (1.2-3.1-fold; p = 0.001) were measured with OSHA42 compared with the impinger. The IsoChek did not detect HDI monomer, and of the three samplers analyzed by laboratories other than UNC (i.e., OSHA42, IsoChek, and WA-DOSH), the WA-DOSH was in the best agreement with the impingers. The influence of clearcoat drying time on the sampler's ability to measure monomeric and polymeric HDI emphasizes the importance of the speciation of diisocyanates in chemical analysis and the careful consideration for the selection of the air sampler to be used when measuring exposures during

  1. Field evaluation of sampling and analysis for organic pollutants in indoor air. Project summary

    SciTech Connect

    Chuang, J.C.; Mack, G.A.; Stockrahm, J.W.; Hannan, S.W.; Bridges, C.

    1988-09-01

    The objectives of the study were to determine the feasibility of the use of newly developed indoor air samplers in residential indoor air sampling and to evaluate methodology for characterization of the concentrations of polynuclear aromatic hydrocarbons (PAH), PAH derivatives, and nicotine in residential air.

  2. Indoor air quality of four Southern High Plains dairy milking parlors in the summer and winter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Milking parlor indoor air quality of 4 large dairies was sampled to investigate: (1) bacterial and fungal concentration/m**3 of air, (2) bioaerosol microbial types, and (3) respirable and non-respirable bioaerosol concentrations/m**3 of air. Equipment used were cascade biological samplers, a laser s...

  3. A simple pore water hydrogen diffusion syringe sampler

    USGS Publications Warehouse

    Vroblesky, D.A.; Chapelle, F.H.; Bradley, P.M.

    2007-01-01

    Molecular hydrogen (H2) is an important intermediate product and electron donor in microbial metabolism. Concentrations of dissolved H 2 are often diagnostic of the predominant terminal electron-accepting processes in ground water systems or aquatic sediments. H2 concentrations are routinely measured in ground water monitoring wells but are rarely measured in saturated aquatic sediments due to a lack of simple and practical sampling methods. This report describes the design and development (including laboratory and field testing) of a simple, syringe-based H 2 sampler in (1) saturated, riparian sediments, (2) surface water bed sediments, and (3) packed intervals of a fractured bedrock borehole that are inaccessible by standard pumped methods. ?? 2007 National Ground Water Association.

  4. Treating Soil Solution Samplers To Prevent Microbial Removal of Analytes

    PubMed Central

    Lewis, David L.; Simons, Alex P.; Moore, W. Bruce; Gattie, David K.

    1992-01-01

    Soil microorganisms colonizing soil water sampling devices (lysimeters) reduced concentrations of biodegradable organic chemicals, including 2,4-dichlorophenoxyacetic acid methyl ester, alachlor, methyl m-chlorobenzoate, and metolachlor as water entered through porous ceramic cups. In some cases, losses exceeded 99%. Additions of either a biocide (sodium hypochlorite) or a bacteriostat (copper salt) prevented microbial activity so that concentrations of test chemicals inside lysimeters equaled those outside. Field studies further indicated that treating lysimeters with a copper salt effectively prevented microbial activity. Thus, chemically treating soil water samplers could improve the accuracy of soil water data for a wide variety of analytes, including environmentally important organics, such as pesticides and industrial wastes, and inorganics, such as ammonia and nitrate. Images PMID:16348616

  5. Two-Stage Variable Sample-Rate Conversion System

    NASA Technical Reports Server (NTRS)

    Tkacenko, Andre

    2009-01-01

    A two-stage variable sample-rate conversion (SRC) system has been pro posed as part of a digital signal-processing system in a digital com munication radio receiver that utilizes a variety of data rates. The proposed system would be used as an interface between (1) an analog- todigital converter used in the front end of the receiver to sample an intermediatefrequency signal at a fixed input rate and (2) digita lly implemented tracking loops in subsequent stages that operate at v arious sample rates that are generally lower than the input sample r ate. This Two-Stage System would be capable of converting from an input sample rate to a desired lower output sample rate that could be var iable and not necessarily a rational fraction of the input rate.

  6. Field tests of nylon-screen diffusion samplers and pushpoint samplers for detection of metals in sediment pore water, Ashland and Clinton, Massachusetts, 2003

    USGS Publications Warehouse

    Zimmerman, Marc J.; Vroblesky, Don A.; Campo, Kimberly W.; Massey, Andrew J.; Scheible, Walter

    2005-01-01

    Efficient and economical screening methods are needed to detect and to determine the approximate concentrations of potentially toxic trace-element metals in shallow groundwater- discharge areas (pore water) where the metals may pose threats to aquatic organisms; such areas are likely to be near hazardous-waste sites. Pushpoint and nylon-screen diffusion samplers are two complementary options for use in such environments. The pushpoint sampler, a simple well point, is easy to insert manually and to use. Only 1 day is required to collect samples. The nylon-screen diffusion sampler is well suited for use in sediments that do not allow a pump to draw water into a pushpoint sampler. In this study, both types of devices were used in sediments suitable for the use of the pushpoint sampler. Sampling with the nylon-screen diffusion sampler requires at least two site visits: one to deploy the samplers in the sediment, and a second to retrieve the samplers and collect the samples after a predetermined equilibration period. Extensive laboratory quality-control studies, field testing, and laboratory analysis of samples collected at the Nyanza Chemical Waste Dump Superfund site along the Sudbury River in Ashland, Massachusetts, and at a Superfund site-assessment location on Rigby Brook in Clinton, Massachusetts, indicate that these two devices yield comparable results for most metals and should be effective tools for pore-water studies. The nylon-screen diffusion samplers equilibrated within 1-2 days in homogeneous, controlled conditions in the laboratory. Nylon-screen diffusion samplers that were not purged of dissolved oxygen prior to deployment yielded results similar to those that were purged. Further testing of the nylon-screen diffusion samplers in homogeneous media would help to resolve any ambiguities about the data variability from the field studies. Comparison of data from replicate samples taken in both study areas shows that even samples taken from sites within a

  7. Design Optimization of a Portable Thermophoretic Precipitator Nanoparticle Sampler

    PubMed Central

    Miller, Art; Marinos, Alek; Wendel, Chris; King, Grant; Bugarski, Aleksandar

    2015-01-01

    Researchers at the National Institute for Occupational Safety and Health (NIOSH) are developing methods for characterizing diesel particulate matter in mines. Introduction of novel engine and exhaust after treatment technologies in underground mines is changing the nature of diesel emissions, and metrics alternative to the traditional mass-based measurements are being investigated with respect to their ability to capture changes in the properties of diesel aerosols. The emphasis is given to metrics based on measurement of number and surface area concentrations, but analysis of collected particles using electron microscopy (EM) is also employed for detailed particle characterization. To collect samples for EM analysis at remote workplaces, including mining and manufacturing facilities, NIOSH is developing portable particle samplers capable of collecting airborne nano-scale particles. This paper describes the design, construction, and testing of a prototype thermophoretic precipitator (TP) particle sampler optimized for collection of particles in the size range of 1–300 nm. The device comprises heated and cooled metal plates separated by a 0.8 mm channel through which aerosol is drawn by a pump. It weighs about 2 kg, has a total footprint of 27 × 22 cm, and the collection plate size is approximately 4 × 8 cm. Low power consumption and enhanced portability were achieved by using moderate flow rates (50–150 cm3/min) and temperature gradients (10–50 K/mm with ΔT between 8 K and 40 K). The collection efficiency of the prototype, measured with a condensation particle counter using laboratory-generated polydisperse submicrometer NaCl aerosols, ranged from 14–99%, depending on temperature gradient and flow rate. Analysis of transmission electron microscopy images of samples collected with the TP confirmed that the size distributions of collected particles determined using EM are in good agreement with those determined using a Fast Mobility Particle Sizer. PMID

  8. Determining the spatial variability of personal sampler inlet locations

    SciTech Connect

    Vinson, R.; Volkwein, J.; Mcwilliams, L.

    2007-09-15

    This article examines the spatial variability of dust concentrations within a coal miner's breathing zone and the impact of sampling location at the cap lamp, nose, and lapel. Tests were conducted in the National Institute for Safety and Health Pittsburgh Research Laboratory full-scale, continuous miner gallery using three prototype personal dust monitors (PDM). The dust masses detected by the PDMs were used to calculate the percentage difference of dust mass between the cap lamp and the nose and between the lapel and the nose. The calculated percentage differences of the masses ranged from plus 12% to minus 25%. Breathing zone tests were also conducted in four underground coal mines using the torso of a mannequin to simulate a miner. Coal mine dust was sampled with multi-cyclone sampling cans mounted directly in front of the mannequin near the cap lamp, nose, and lapel. These four coal mine tests found that the spatial variability of dust levels and imprecision of the current personal sampler is a greater influence than the sampler location within the breathing zone. However, a one-sample t-test of this data did find that the overall mean value of the cap lamp/nose ratio was not significantly different than 1 (p-value = 0.21). However; when applied to the overall mean value of the lapel/nose ratio there was a significant difference from 1 (p-value < 0.0001). This finding is important because the lapel has always been the sampling location for coal mine dust samples. But these results suggest that the cap location is slightly more indicative of what is breathed through the nose area.

  9. Development of a new semi-volatile organic compound sampler

    SciTech Connect

    Sioutas, C.; Koutrakis, P.; Burton, R.M.

    1994-12-31

    A new sampler has been developed to sample semi-volatile organic compounds. The sampler utilizes the principle of virtual impactor to efficiently separate the particulate from the gas phases of organic compounds. The virtual impactor consists of a slit-shaped nozzle where the aerosol is accelerated, and another slit-shaped nozzle that collects the particulate phase of organics (plus a small and known fraction of the gas phase). The acceleration slit is 0.023 cm wide, the collection slit is 0.035 cm wide, and both slits are 11 cm long. The virtual impactor`s 50% cutpoint has been determined experimentally to be 0.12 {micro}m. In addition, interstage losses have been determined (in all configurations tested, particle losses ranged from 5--15%). The impactor`s sampling flow rate is 284 liters/minute, with a corresponding pressure drop of 100 inches H{sub 2}O. Higher or lower sampling flow rates can be achieved by increasing or decreasing the length of the slits. Tests for volatilization losses have been conducted by generating organic aerosols of known volatility, and comparing the impactor`s collection to that of a filter pack sampling in parallel. The experiments demonstrated negligible volatilization losses (< 5%) for the compounds tried. Particles are collected on a filter connected to the minor flow of the impactor, followed by a sorbent bed to collect material that volatilized from the particles. The organic gas phases is collected on a sorbent bed, connected to the major flow of the impactor.

  10. Myxovirus Dissemination by Air

    PubMed Central

    McLean, D. M.; Bannatyne, R. M.; Givan, Kathleen F.

    1967-01-01

    Myxoviruses including 150 strains of parainfluenza 1, 15 of parainfluenza 3 and five of influenza B virus were isolated from nasopharyngeal secretions obtained from 300 children less than 3 years of age who developed acute laryngotracheobronchitis during the preceding 48 hours. The patients were examined between October 1966 and January 1967, the peak monthly rate of virus isolation (67%) occurring during January. Parainfluenza 1 virus was isolated from air obtained in the vicinity of one of 30 children whose nasopharyngeal secretions yielded this agent. Samples comprising 150 litres of air were collected for virus assay by placing an Andersen sampler about 60 cm. from the child's face inside an oxygen tent which surrounded the patient. These findings confirm previous observations that parainfluenza 1 virus is the dominant agent associated with acute laryngotracheobronchitis in children in Toronto, and they show that this virus is disseminated in the air. PMID:4290621

  11. JPCam: Status of the 1.2Gpixel camera for the J-PAS survey.

    NASA Astrophysics Data System (ADS)

    Taylor, Keith; Marín-Franch, Antonio; Santoro, Fernando; Mendes de Oliveira, Claudia; Dupke, Renato

    2015-08-01

    JPCam is a 14-CCD mosaic camera, using the new e2v 9k-by-9k, 10 micron pixel detectors, to be deployed on the JST/T250, a dedicated 2.55m wide-field telescope at the OAJ (Observatorio Astrofísico de Javalambre) in Teruel, Spain. The camera is designed to perform the J-PAS, a BAO survey of the northern sky. The J-PAS survey strategy will use 59 filters, 56 relatively narrow-band (14.5nm) filters equi-spaced between 350 and 1000nm plus 3 broad-band filters to achieve unprecedented photometric red-shift accuracies for faint galaxies over 8000 square degrees of sky. The cryostat, detector mosaic and read electronics is being supplied by e2v. Each science detector is read from 16 ports simultaneously, allowing read times of 14s with a typical read noise of 5e- (rms). The JPCam focal plane will be complemented with 4 autoguiding and 8 wavefront sensing CCDs. Image quality over the whole CCD mosaic will be maintained by applying the required, close loop, focus, tilt and rotation adjustments to the focal plane through the JPCam hexapod actuator system, manufactured by NTE-Sener. The filter unit has been designed to admit 5 filter trays, each mounting 14 filters corresponding to the 14 CCDs of the mosaic. Each CCD will view only its corresponding filter avoiding optical cross-talk from their neighbors. With this configuration, JPCam will cover 4.7 square degrees with a plate scale of 0.2267 arcsec/pix and will allow all the J-PAS filters to be permanently installed on the camera. The massive 525mm aperture shutter is supplied by Bonn-Shutter UG.

  12. Second Annual Maintenance, Inspection, and Test Report for PAS-1 Cask Certification for Shipping Payload B

    SciTech Connect

    KELLY, D.J.

    2000-10-09

    The Nuclear Packaging, Inc. (NuPac), PAS-1 cask is required to undergo annual maintenance and inspections to retain certification in accordance with U.S. Department of Energy (DOE) Certificate of Compliance USA/9184B(U) (Appendix A). The packaging configuration being tested and maintained is the NuPac PAS-1 cask for Payload B. The intent of the maintenance and inspections is to ensure the packaging remains in unimpaired physical condition. Two casks, serial numbers 2162-026 and 2162-027, were maintained, inspected, and tested at the 306E Development, Fabrication, and Test Laboratory, located at the Hanford Site's 300 Area. Waste Management Federal Services, Inc. (WMFS), a subsidiary of GTS Duratek, was in charge of the maintenance and testing. Cogema Engineering Corporation (Cogema) directed the operations in the test facility. The maintenance, testing, and inspections were conducted successfully with both PAS-1 casks. The work conducted on the overpacks included weighing, gasket replacement, and plastic pipe plug and foam inspections. The work conducted on the secondary containment vessel (SCV) consisted of visual inspection of the vessel and threaded parts (i.e., fasteners), visual inspection of sealing surfaces, replacement of O-ring seals, and a helium leak test. The work conducted on the primary containment vessel (PCV) consisted of visual inspection of the vessel and threaded parts (i.e., fasteners), visual inspection of sealing surfaces, replacement of O-ring seals, dimensional inspection of the vessel bottom, a helium leak test, and dye penetrant inspection of the welds. The vermiculite material used in the cask rack assembly was replaced.

  13. Protective effects of ebselen (Ebs) and para-aminosalicylic acid (PAS) against manganese (Mn)-induced neurotoxicity

    SciTech Connect

    Marreilha dos Santos, A.P.; Lucas, Rui L.; Andrade, Vanda; Mateus, M. Luísa; Milatovic, Dejan; Aschner, Michael; Batoreu, M. Camila

    2012-02-01

    Chronic, excessive exposure to manganese (Mn) may induce neurotoxicity and cause an irreversible brain disease, referred to as manganism. Efficacious therapies for the treatment of Mn are lacking, mandating the development of new interventions. The purpose of the present study was to investigate the efficacy of ebselen (Ebs) and para-aminosalicylic acid (PAS) in attenuating the neurotoxic effects of Mn in an in vivo rat model. Exposure biomarkers, inflammatory and oxidative stress biomarkers, as well as behavioral parameters were evaluated. Co-treatment with Mn plus Ebs or Mn plus PAS caused a significant decrease in blood and brain Mn concentrations (compared to rats treated with Mn alone), concomitant with reduced brain E{sub 2} prostaglandin (PGE{sub 2}) and enhanced brain glutathione (GSH) levels, decreased serum prolactin (PRL) levels, and increased ambulation and rearing activities. Taken together, these results establish that both PAS and Ebs are efficacious in reducing Mn body burden, neuroinflammation, oxidative stress and locomotor activity impairments in a rat model of Mn-induced toxicity. -- Highlights: ► The manuscript is unique in its approach to the neurotoxicity of Mn. ► The manuscript incorporates molecular, cellular and functional (behavioral) analyses. ► Both PAS and Ebs are effective in restoring Mn behavioral function. ► Both PAS and Ebs are effective in reducing Mn-induced oxidative stress. ► Both PAS and Ebs led to a decrease in Mn-induced neuro-inflammation.

  14. [Gardner syndrome--parent alienation syndrome (PAS). Diagnosis or family reality?].

    PubMed

    Namysłowska, Irena; Heitzman, Janusz; Siewierska, Anna

    2009-01-01

    The authors present characteristics of Parental Alienation Syndrome (PAS) proposed by Gardner as well as data, which may help to differentiate that syndrome with real psychological, physical and sexual abuse. The consequences of Gardner Syndrome for legal decisions in the court cases of child custody and the critique of this syndrome in forensic and psychiatric literature are also discussed, and several questions posed. Authors propose to treat Gardner Syndrome not as as a child disorder but as a specific, dynamic family situation, which occurs sometimes, during divorce and fight about child custody.

  15. Development of a Dehumidification System for a Passive Sampler for Determining 1,3-Butadiene.

    PubMed

    Sakurai, Kenji; Miyake, Yuichi; Amagai, Takashi

    2016-09-01

    The passive sampler is a simple device for collecting gaseous compounds. It is affected by environmental conditions such as relative humidity, but a dehumidification system (DHS) has not been developed for it. We have developed a dehumidification device for the passive sampler for determining 1,3-butadiene. It consists of a passive sampler surrounded by a DHS consisting of a basket filled with granular magnesium perchlorate as the dehumidification agent. The passive sampler consists of a porous polytetrafluoroethylene tube packed with Carboxen 1000 adsorbent. We compared the amounts of water adsorbed on the Carboxen 1000 adsorbent in the presence and in the absence of the DHS; the results showed that the DHS prevented water from entering the sampler. Volatile organic compounds that entered the sampler were collected by the Carboxen 1000 adsorbent. In the case of 1,3-butadiene, much higher amounts were collected by the passive sampler with the DHS than without it. This may be due to interference of adsorption or acceleration of 1,3-butadiene degradation by the water-soluble oxidant on the surface of the Carboxen 1000 adsorbent. PMID:27627969

  16. AN AFFINE-INVARIANT SAMPLER FOR EXOPLANET FITTING AND DISCOVERY IN RADIAL VELOCITY DATA

    SciTech Connect

    Hou Fengji; Hogg, David W.; Goodman, Jonathan; Weare, Jonathan; Schwab, Christian

    2012-02-01

    Markov chain Monte Carlo (MCMC) proves to be powerful for Bayesian inference and in particular for exoplanet radial velocity fitting because MCMC provides more statistical information and makes better use of data than common approaches like chi-square fitting. However, the nonlinear density functions encountered in these problems can make MCMC time-consuming. In this paper, we apply an ensemble sampler respecting affine invariance to orbital parameter extraction from radial velocity data. This new sampler has only one free parameter, and does not require much tuning for good performance, which is important for automatization. The autocorrelation time of this sampler is approximately the same for all parameters and far smaller than Metropolis-Hastings, which means it requires many fewer function calls to produce the same number of independent samples. The affine-invariant sampler speeds up MCMC by hundreds of times compared with Metropolis-Hastings in the same computing situation. This novel sampler would be ideal for projects involving large data sets such as statistical investigations of planet distribution. The biggest obstacle to ensemble samplers is the existence of multiple local optima; we present a clustering technique to deal with local optima by clustering based on the likelihood of the walkers in the ensemble. We demonstrate the effectiveness of the sampler on real radial velocity data.

  17. An Affine-invariant Sampler for Exoplanet Fitting and Discovery in Radial Velocity Data

    NASA Astrophysics Data System (ADS)

    Hou, Fengji; Goodman, Jonathan; Hogg, David W.; Weare, Jonathan; Schwab, Christian

    2012-02-01

    Markov chain Monte Carlo (MCMC) proves to be powerful for Bayesian inference and in particular for exoplanet radial velocity fitting because MCMC provides more statistical information and makes better use of data than common approaches like chi-square fitting. However, the nonlinear density functions encountered in these problems can make MCMC time-consuming. In this paper, we apply an ensemble sampler respecting affine invariance to orbital parameter extraction from radial velocity data. This new sampler has only one free parameter, and does not require much tuning for good performance, which is important for automatization. The autocorrelation time of this sampler is approximately the same for all parameters and far smaller than Metropolis-Hastings, which means it requires many fewer function calls to produce the same number of independent samples. The affine-invariant sampler speeds up MCMC by hundreds of times compared with Metropolis-Hastings in the same computing situation. This novel sampler would be ideal for projects involving large data sets such as statistical investigations of planet distribution. The biggest obstacle to ensemble samplers is the existence of multiple local optima; we present a clustering technique to deal with local optima by clustering based on the likelihood of the walkers in the ensemble. We demonstrate the effectiveness of the sampler on real radial velocity data.

  18. New aerosol sampler with low wind sensitivity and good filter collection uniformity

    NASA Astrophysics Data System (ADS)

    Kalatoor, Suresh; Grinshpun, Sergey A.; Willeke, Klaus; Baron, Paul

    The overall sampling efficiency of many aerosol samplers is sensitive to wind velocity and direction. In addition, most samplers have internal losses due to gravitational settling, electrostatic interactions, and internal turbulence. A new sampling inlet has been designed to reduce these problems. The flow patterns over the new prototype sampler were visualized in a horizontal wind tunnel. Visualization of the streamlines over the new sampler and limiting-streamline quantitative analysis showed negligible turbulence effects due to the inlet's geometry. The overall sampling efficiency of the prototype sampler was compared to that of a 25 mm closed-face cassette. Uranine was used as the challenge aerosol with particle physical diameters of 13.5, 20 and 30 μm. The wind velocity ranged from 100 to 300 cm s -1. Evaluation of the data showed the new sampler to be less significantly affected by wind direction and magnitude. The particle distribution observed on the sampler's filter was found to be reasonably uniform, an advantage for several types of analyses.

  19. Feasibility Study of Passive Aerosol Sampler for Bio-Agent Detection

    SciTech Connect

    Keating, G

    2003-03-05

    We propose to establish the feasibility of a passive aerosol sampler for bio-agent collection through laboratory experiments and theoretical analysis. The passive sampler, unlike the typical active sampler, does not require pumps and complex fixtures, and thereby allows for large-scale field monitoring not possible with current active samplers. We plan to conduct experiments using model (both biological and non-biological) aerosols generated in an instrumented test chamber and compare the particles collected on various passive samplers to conventional filter samplers, commercial aerosol measuring instruments and to conventional surface swipes. Theoretical analysis will be used to design prototype passive samplers and to compare experimental results with theory. A successful feasibility study will be used to seek outside funding for applications that will greatly enhance current LLNL programs such as NARAC's atmospheric dispersal modeling, NAI's programs in bioagent monitoring in public locations and fixed sampling stations, and EPD's environmental monitoring and decontamination research. In addition, the feasibility study will position us favorably for responding to new calls for proposals by NIH and EPA for large scale environmental studies.

  20. Neural Network Based State of Health Diagnostics for an Automated Radioxenon Sampler/Analyzer

    SciTech Connect

    Keller, Paul E.; Kangas, Lars J.; Hayes, James C.; Schrom, Brian T.; Suarez, Reynold; Hubbard, Charles W.; Heimbigner, Tom R.; McIntyre, Justin I.

    2009-05-13

    Artificial neural networks (ANNs) are used to determine the state-of-health (SOH) of the Automated Radioxenon Analyzer/Sampler (ARSA). ARSA is a gas collection and analysis system used for non-proliferation monitoring in detecting radioxenon released during nuclear tests. SOH diagnostics are important for automated, unmanned sensing systems so that remote detection and identification of problems can be made without onsite staff. Both recurrent and feed-forward ANNs are presented. The recurrent ANN is trained to predict sensor values based on current valve states, which control air flow, so that with only valve states the normal SOH sensor values can be predicted. Deviation between modeled value and actual is an indication of a potential problem. The feed-forward ANN acts as a nonlinear version of principal components analysis (PCA) and is trained to replicate the normal SOH sensor values. Because of ARSA’s complexity, this nonlinear PCA is better able to capture the relationships among the sensors than standard linear PCA and is applicable to both sensor validation and recognizing off-normal operating conditions. Both models provide valuable information to detect impending malfunctions before they occur to avoid unscheduled shutdown. Finally, the ability of ANN methods to predict the system state is presented.

  1. Wind tunnel calibration of the USGS dust deposition sampler: Sampling efficiency and grain size correction

    NASA Astrophysics Data System (ADS)

    Goossens, Dirk

    2010-11-01

    Wind tunnel experiments were conducted with the USGS (United States Geological Survey) dust deposition sampler to test its efficiency for dust deposition and its capacity to collect representative samples for grain size analysis. Efficiency for dust deposition was ascertained relative to a water surface, which was considered the best alternative for simulating a perfectly absorbent surface. Capacity to collect representative samples for grain size analysis was ascertained by comparing the grain size distribution of the collected dust to that of the original dust. Three versions were tested: an empty sampler, a sampler filled with glass marbles, and a sampler filled with water. Efficiencies and capacity to collect representative samples were ascertained for five wind velocities (range: 1-5 m s -1) and seven grain size classes (range: 10-80 μm). All samplers showed a rapid drop in collection efficiency with increasing wind speed. Efficiencies are low, in the order of 10% or less for most common wind speeds over the continents. Efficiency also drops as the particles become coarser. Adding glass marbles to the sampler increases its efficiency, protects the settled dust from resuspension, and minimizes outsplash during rainfall. The sediment collected by the sampler is finer than the original dust. The bias in the grain size is more expressed in fine particle fractions than in coarse particle fractions. The performance of the USGS sampler is rather low when compared to other dust deposition samplers, but a procedure is provided that allows calculation of the original grain size distribution and dust deposition quantities.

  2. Numerical modeling of free-drainage water samplers in the shallow vadose zone

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Warrick, A. W.; Artiola, J. F.

    A finite element model was used to simulate the performance of a free-drainage sampler. This device may be used to collect soil water by free drainage in the shallow vadose zone. A unique feature of this sampling device is that it serves as a barrier to flow and creates a locally saturated region in an otherwise unsaturated system. Steady and unsteady flows were modeled assuming the hydraulic functions of van Genuchten and Gardner. Results include flux into the sampler and distribution of hydraulic head as functions of soil hydraulic properties, background soil flux and sampler size.

  3. Purification and characterization of novel whey glycoprotein WGP-88 which binds to a monoclonal antibody to PAS-4 glycoprotein in the bovine milk fat globule membrane.

    PubMed

    Hwangbo, S; Azuma, N; Kurisaki, J; Kanno, C

    1997-09-01

    A monoclonal antibody to the PAS-4 glycoprotein (78 kDa) of the bovine milk fat globule membrane (MFGM) specifically recognized PAS-4, and was named KAS4. A component recognized by KAS4 was found in whey protein, this being a glycoprotein of 88 kDa by SDS-PAGE and named WGP-88. WGP-88 was purified and characterized in comparison with PAS-4. WGP-88 had apparent pI values of 6.45 and 6.39, while those of PAS-4 were 7.39 and 7.35. Neuraminidase digestion shifted the pI values of WGP-88 to 6.57 and of PAS-4 to 7.52. WGP-88 was rich in polar amino residues (44.9 mol%), while PAS-4 was abundant in nonpolar amino acid residues (48.7 mol%). WGP-88 contained 17.1% of carbohydrate and PAS-4 had 7.2%. The results of reductive hydrolysis, N-glycanase digestion, and a lectin blot analysis suggested that N- and O-linked sugar chains were contained in both glycoproteins. WGP-88 and PAS-4 had a different N-terminal amino acid sequence. WGP-88 and PAS-4 respectively inhibited competitively the binding of KAS4 to PAS-4 and WGP-88. Our studies revealed WGP-88 recognized by KAS4 mAb to be a novel whey protein and to have different biochemical properties from those of PAS-4.

  4. Topological control of the Caulobacter cell cycle circuitry by a polarized single-domain PAS protein

    PubMed Central

    Sanselicio, Stefano; Bergé, Matthieu; Théraulaz, Laurence; Radhakrishnan, Sunish Kumar; Viollier, Patrick H.

    2015-01-01

    Despite the myriad of different sensory domains encoded in bacteria, only a few types are known to control the cell cycle. Here we use a forward genetic screen for Caulobacter crescentus motility mutants to identify a conserved single-domain PAS (Per-Arnt-Sim) protein (MopJ) with pleiotropic regulatory functions. MopJ promotes re-accumulation of the master cell cycle regulator CtrA after its proteolytic destruction is triggered by the DivJ kinase at the G1-S transition. MopJ and CtrA syntheses are coordinately induced in S-phase, followed by the sequestration of MopJ to cell poles in Caulobacter. Polarization requires Caulobacter DivJ and the PopZ polar organizer. MopJ interacts with DivJ and influences the localization and activity of downstream cell cycle effectors. Because MopJ abundance is upregulated in stationary phase and by the alarmone (p)ppGpp, conserved systemic signals acting on the cell cycle and growth phase control are genetically integrated through this conserved single PAS-domain protein. PMID:25952018

  5. Inhibitory PAS domain protein is a negative regulator of hypoxia-inducible gene expression

    NASA Astrophysics Data System (ADS)

    Makino, Yuichi; Cao, Renhai; Svensson, Kristian; Bertilsson, Göran; Asman, Mikael; Tanaka, Hirotoshi; Cao, Yihai; Berkenstam, Anders; Poellinger, Lorenz

    2001-11-01

    Alteration of gene expression is a crucial component of adaptive responses to hypoxia. These responses are mediated by hypoxia-inducible transcription factors (HIFs). Here we describe an inhibitory PAS (Per/Arnt/Sim) domain protein, IPAS, which is a basic helix-loop-helix (bHLH)/PAS protein structurally related to HIFs. IPAS contains no endogenous transactivation function but demonstrates dominant negative regulation of HIF-mediated control of gene expression. Ectopic expression of IPAS in hepatoma cells selectively impairs induction of genes involved in adaptation to a hypoxic environment, notably the vascular endothelial growth factor (VEGF) gene, and results in retarded tumour growth and tumour vascular density in vivo. In mice, IPAS was predominantly expressed in Purkinje cells of the cerebellum and in corneal epithelium of the eye. Expression of IPAS in the cornea correlates with low levels of expression of the VEGF gene under hypoxic conditions. Application of an IPAS antisense oligonucleotide to the mouse cornea induced angiogenesis under normal oxygen conditions, and demonstrated hypoxia-dependent induction of VEGF gene expression in hypoxic corneal cells. These results indicate a previously unknown mechanism for negative regulation of angiogenesis and maintenance of an avascular phenotype.

  6. A case study of personal exposure to nitrogen dioxide using a new high sensitive diffusive sampler.

    PubMed

    Piechocki-Minguy, A; Plaisance, H; Schadkowski, C; Sagnier, I; Saison, J Y; Galloo, J C; Guillermo, R

    2006-07-31

    Personal NO(2) exposure measurements were achieved during two campaigns in a large northern France city. These campaigns were following an innovating approach based on sequential exposure measurements by diffusive samplers distinguishing four categories of microenvironments ("home", "other indoor places", "transport" and "outdoors"). The objective of these campaigns was to obtain NO(2) personal exposure data in different microenvironments and to examine the determinants of personal exposure to this pollutant. Each campaign comprised two 24-h sampling periods: one during a working day and the second during the weekend. The average total NO(2) personal exposure ranged from 17 microg m(-3) for the summer weekend samplings to 38 microg m(-3) for the winter weekday samplings. The highest levels were found in transports and outdoors, the intermediate ones in other indoor places and the lowest in homes. Despite their weak levels, indoor environments contributed for more than 78% to total NO(2) personal exposure because of more time spent in these living places. A Multiple Correspondence Analysis (MCA) highlighted the determinants of NO(2) personal exposure in the "home" and "transport" microenvironments. This led to a classification of NO(2) personal exposure levels according to different means of transport: from the lowest to the highest exposure levels, train, tramway or underground, bicycle, car or motorcycle. In homes, the rise of NO(2) personal exposures is mainly due to the use of gas stoves and gas heating and the absence of automatic airing system. A classification of NO(2) personal exposure levels was set up according to the characteristics of homes. An analysis of correlations between the home NO(2) personal exposures and outdoor concentrations measured by fixed ambient air monitoring stations showed weak relations suggesting that the data of these stations are poor predictors of NO(2) personal exposures in homes. PMID:16154618

  7. A case study of personal exposure to nitrogen dioxide using a new high sensitive diffusive sampler.

    PubMed

    Piechocki-Minguy, A; Plaisance, H; Schadkowski, C; Sagnier, I; Saison, J Y; Galloo, J C; Guillermo, R

    2006-07-31

    Personal NO(2) exposure measurements were achieved during two campaigns in a large northern France city. These campaigns were following an innovating approach based on sequential exposure measurements by diffusive samplers distinguishing four categories of microenvironments ("home", "other indoor places", "transport" and "outdoors"). The objective of these campaigns was to obtain NO(2) personal exposure data in different microenvironments and to examine the determinants of personal exposure to this pollutant. Each campaign comprised two 24-h sampling periods: one during a working day and the second during the weekend. The average total NO(2) personal exposure ranged from 17 microg m(-3) for the summer weekend samplings to 38 microg m(-3) for the winter weekday samplings. The highest levels were found in transports and outdoors, the intermediate ones in other indoor places and the lowest in homes. Despite their weak levels, indoor environments contributed for more than 78% to total NO(2) personal exposure because of more time spent in these living places. A Multiple Correspondence Analysis (MCA) highlighted the determinants of NO(2) personal exposure in the "home" and "transport" microenvironments. This led to a classification of NO(2) personal exposure levels according to different means of transport: from the lowest to the highest exposure levels, train, tramway or underground, bicycle, car or motorcycle. In homes, the rise of NO(2) personal exposures is mainly due to the use of gas stoves and gas heating and the absence of automatic airing system. A classification of NO(2) personal exposure levels was set up according to the characteristics of homes. An analysis of correlations between the home NO(2) personal exposures and outdoor concentrations measured by fixed ambient air monitoring stations showed weak relations suggesting that the data of these stations are poor predictors of NO(2) personal exposures in homes.

  8. Errors in ozone risk assessment using standard conditions for converting ozone concentrations obtained by passive samplers in mountain regions.

    PubMed

    Gerosa, G; Finco, A; Marzuoli, R; Ferretti, M; Gottardini, E

    2012-05-01

    Passive samplers are often employed to measure ozone concentrations in remote areas such as mountain forests. The potential ozone risk for vegetation is then assessed by calculating the AOT40 exposure index (accumulated hourly ozone concentration exceedances above 40 ppb, i.e. AOT40 = Σ([O(3)] - 40)Δt for any hourly ozone concentration [O(3)] > 40 ppb). AOT40 is customary calculated on the basis of ozone concentrations expressed as a volumetric mixing ratio, while lab sheets normally report ozone concentrations from passive samplers in mass units per cubic metre. Concentrations are usually converted from mass units to ppb using a standard conversion factor taking SATP (Standard Ambient Temperature and Pressure) conditions into account. These conditions, however, can vary considerably with elevation. As a consequence, the blanket application of a standard conversion factor may lead to substantial errors in reporting and mapping ozone concentrations and therefore in assessing potential ozone risk in mountain regions. In this paper we carry out a sensitivity analysis of the effects of uncertainties in estimations of air temperature (T) and atmospheric pressure (P) on the concentration conversion factor, and present two examples from two monitoring and mapping exercises carried out in the Italian Alps. We derived P and T at each site from adiabatic lapse rates for temperature and pressure and analysed the magnitude of error in concentration estimations. Results show that the concentration conversion is much more sensitive to uncertainties in P gradient estimation than to air temperature errors. The concentration conversion factor (cf) deviates 5% from the standard transformation at an elevation of 500 m asl. As a consequence, the standard estimated AOT40 at this elevation is about 13% less than the actual value. AOT40 was found to be underestimated by an average between 25% and 34% at typical elevations of mountain forest stands in the Italian Alps when a correct

  9. Application of FTIR-PAS and Raman spectroscopies for the determination of organic matter in farmland soils.

    PubMed

    Xing, Zhe; Du, Changwen; Tian, Kang; Ma, Fei; Shen, Yazhen; Zhou, Jianmin

    2016-09-01

    In soil analysis, Raman spectroscopy is not as widely used as infrared spectroscopy mainly owing to fluorescence interferences. This paper investigated the feasibility of Fourier-transform infrared photoacoustic (FTIR-PAS) and Raman spectroscopies for predicting soil organic matter (SOM) using partial least squares regression (PLSR) analysis. 194 farmland soil samples were collected and scanned with FTIR and Raman spectrometers in the spectral range of 4000-400cm(-1) and 180-3200cm(-1), respectively. For the PLSR models, the combined dataset was split into 146 samples as the calibration set (75%) and 48 samples as the validation set (25%). The optimal number of analytical factors was determined using a leave-one-out cross-validation. The results showed that SOM could be predicted using FTIR-PAS and Raman spectroscopies independently, with R(2)>0.70 and RPD>1.8 for the validation sets. In comparison to the single applications of FTIR-PAS and Raman spectroscopies, accurate prediction of SOM was made by combining FTIR-PAS and Raman spectroscopies, with R(2)=0.81 and RPD=2.18 for the validation sets. By statistically assessing large amounts of PLS models, model-population analysis confirmed that the accuracy of the PLS model can be increased by combining FTIR-PAS and Raman spectroscopies. In conclusion, the combination of FTIR-PAS and Raman spectroscopies is a promising alternative for soil characterization, especially for the prediction of SOM, owing to the availability of complementary information from both FTIR-PAS (polar vibrations) and Raman spectroscopy (non-polar vibrations). PMID:27343604

  10. Comparison of flume and towing methods for verifying the calibration of a suspended-sediment sampler

    USGS Publications Warehouse

    Beverage, J.P.; Futrell, J.C.

    1986-01-01

    Suspended-sediment samplers must sample isokinetically (at stream velocity) in order to collect representative water samples of rivers. Each sampler solo by the Federal Interagency Sedimentation Project or by the U.S. Geological Survey Hydrologic Instrumentation Facility has been adjusted to sample isokinetically and tested in a flume to verify the calibration. The test program for a modified U.S. P-61 sampler provided an opportunity to compare flume and towing tank tests. Although the two tests yielded statistically distinct results, the difference between them was quite small. The conclusion is that verifying the calibration of any suspended-sediment sampler by either the flume or towing method should give acceptable results.

  11. Estimation of Measurement Uncertainties for the DGT Passive Sampler Used for Determination of Copper in Water.

    PubMed

    Knutsson, Jesper; Rauch, Sebastien; Morrison, Gregory M

    2014-01-01

    Diffusion-based passive samplers are increasingly used for water quality monitoring. While the overall method robustness and reproducibility for passive samplers in water are widely reported, there has been a lack of a detailed description of uncertainty sources. In this paper an uncertainty budget for the determination of fully labile Cu in water using a DGT passive sampler is presented. Uncertainty from the estimation of effective cross-sectional diffusion area and the instrumental determination of accumulated mass of analyte are the most significant sources of uncertainty, while uncertainties from contamination and the estimation of diffusion coefficient are negligible. The results presented highlight issues with passive samplers which are important to address if overall method uncertainty is to be reduced and effective strategies to reduce overall method uncertainty are presented.

  12. Evaluating Cost when Selecting Performance Reference Compounds for the Environmental Deployment of Polyethylene Passive Samplers

    EPA Science Inventory

    A challenge in environmental passive sampling is determining when equilibrium is achieved between the sampler, target contaminants, and environmental phases. A common approach is the use of performance reference compounds (PRCs) to indicate degree of equilibrium. One logistical...

  13. Selecting Performance Reference Compounds (PRCS)for Polyethylene Passive Samplers Deployed at Contaminated Sediment Sites

    EPA Science Inventory

    Use of equilibrium passive samplers for performing aquatic environmental monitoring at contaminated sediment sites, including Superfund sites, is becoming more common. However, a current challenge in passive sampling is determining when equilibrium is achieved between the sampl...

  14. Characterization and Application of Passive Samplers for Monitoring of Pesticides in Water.

    PubMed

    Ahrens, Lutz; Daneshvar, Atlasi; Lau, Anna E; Kreuger, Jenny

    2016-01-01

    Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study provides a protocol for the passive sampler preparation, calibration, extraction method and instrumental analysis. Sampling rates (RS) and passive sampler-water partition coefficients (KPW) were calculated for silicone rubber, polar organic chemical integrative sampler POCIS-A, POCIS-B, SDB-RPS and C18 disk. The uptake of the selected compounds depended on their physicochemical properties, i.e., silicone rubber showed a better uptake for more hydrophobic compounds (log octanol-water partition coefficient (KOW) > 5.3), whereas POCIS-A, POCIS-B and SDB-RPS disk were more suitable for hydrophilic compounds (log KOW < 0.70). PMID:27584699

  15. Measuring freely dissolved water concentrations of PCBs using LDPE passive samplers and performance reference compounds (PRCs)

    EPA Science Inventory

    Low-Density polyethylene (LDPE) sheets are often used as passive samplers for aquatic environmental monitoring to measure the dissolved concentrations of hydrophobic organic contaminants (HOCs). These concentrations are then used to evaluate the potential for ecological and human...

  16. Prototype particle stack sampler with virtual impactor nozzle and microcomputer calculating/display system. [H5 Stack Particulate Sampler/Calculator

    SciTech Connect

    Elder, J.C.; Littlefield, L.G.; Tillery, M.I.; Ettinger, H.J.

    1981-07-01

    A prototype particle stack sampler (PPSS) was developed to improve on the existing Environmental Protection Agency (EPA) Method 5 sampling apparatus. Primary features of the stack sampler were: higher sampling rate; display (on demand) of all required variables and calculated values by a microcomputer-based calculating and display system; continuous stack gas moisture determination; a virtual impactor nozzle designed to separate fine and coarse particle fractions; a variable-area inlet to maintain isokinetic sampling conditions; and stainless-steel components rather than the glass specified by EPA Method 5. The calculating and display system incorporates a single component microcomputer, a single-chip 16-channel analog-to-digital converter, a programmable keyboard/display interface, and liquid crystal displays. The scientific calculations capability and associated display have been incorporated to perform and display the results of 24 equations. These results allow the operator to maintain isokinetic sampler probe temperatures, to maintain proper flow through the sampler probe, and to make sampler probe position changes when necessary. The basic sampling technique of particle collection on preweighed filters was retained; however, versatility in the form of optional in-stack filters and general modernization of the stack sampler have been provided in the prototype design. Laboratory testing with monodisperse dye aerosols has shown the present variable-inlet, virtual impactor nozzle to have significant wall losses and a collection efficiency that is less than 77%. This is primarily due to lack of symmetry in this rectangular jet impactor and short transition lengths dictated by physical design constraints (required by passage of the nozzle through a 7.6-cm (3-in.) diameter stack port). Electronic components have shown acceptable service in laboratory testing.

  17. Evaluation of particle resuspension in young children's breathing zone using stationary and robotic (PIPER) aerosol samplers

    PubMed Central

    Sagona, Jessica A.; Shalat, Stuart L; Wang, Zuocheng; Ramagopal, Maya; Black, Kathleen; Hernandez, Marta; Mainelis, Gediminas

    2015-01-01

    Development of asthma in young children may be associated with high exposure to particulate matter (PM). However, typical stationary samplers may not represent the personal exposure of children ages 3 and younger since they may not detect particles resuspended from the floor as children play, thus reducing our ability to correlate exposure and disease etiology. To address this, an autonomous robot, the Pretoddler Inhalable Particulate Environmental Robotic (PIPER) sampler, was developed to simulate the movements of children as they play on the floor. PIPER and a stationary sampler took simultaneous measurements of particle number concentration in six size channels using an optical particle counter and inhalable PM on filters in 65 homes in New Jersey, USA. To study particle resuspension, for each sampler we calculated the ratio of particle concentration measured while PIPER was moving to the average concentration of particles measured during a reference period when PIPER remained still. For all investigated particle sizes, higher particle resuspension was observed by PIPER compared to the stationary sampler. In 71% of carpeted homes a more significant (at the α = 0.05 level) resuspension of particles larger than 2.5 μm was observed by PIPER compared to the stationary sampler. Typically, particles larger than 2.5 μm were resuspended more efficiently than smaller particles, over both carpeted and bare floors. Additionally, in carpeted homes estimations of PM10 mass from the particle number concentrations measured on PIPER while it was moving were on average a factor of 1.54 higher compared to reference period when PIPER was not moving. For comparison, the stationary sampler measured an increase of PM2.5 mass by a factor of only 1.08 when PIPER was moving compared to a reference period. This demonstrates that PIPER is able to resuspend particles through movement, and provide a better characterization of the resuspended particles than stationary samplers. Accurate

  18. Validation of a New Soil VOC Sampler: Precision of the Performance of the En Core Sampler to Store Low VOC Concentrations

    SciTech Connect

    Susan S. Sorini; John F. Schabron; Joseph F. Rovani

    2002-06-01

    Soil sampling and storage practices for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from samples. The En Core{reg_sign} sampler is designed to collect and store soil samples in a manner that minimizes loss of contaminants due to volatilization and/or biodegradation. An American Society for Testing and Materials (ASTM) standard practice, D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, describes use of the En Core sampler to collect and store a soil sample of approximately 5 grams or 25 grams for volatile organic analysis. To support the ASTM practice, four studies have been performed to evaluate the performance of the En Core sampler for storage of soil samples spiked with VOCs. The first study was conducted to evaluate the performance of the device to store soil samples spiked with VOCs at high-level concentrations of approximately 2,500 {micro}g/Kg under various conditions. This analyte concentration in the soil was selected to limit the influence of the analytical method on the data. A second study was conducted to answer questions on the performance of the En Core sampler for storage of soil samples containing low-level (<200 {micro}g/Kg) concentrations of VOCs. In this study, soil samples were spiked with concentrations of VOCs at approximately 100 {micro}g/Kg and stored under various conditions prior to analysis. The third study was performed to generate data on the performance of the 25-gram En Core sampler to store soil samples spiked with EPA Method 1311, Toxicity Characteristic Leaching Procedure (TCLP), volatile organic analytes under various conditions for 14 days. The low-level performance data and TCLP analyte storage data are included in appendices to the ASTM practice, and the ASTM research report describing the high-level study is referenced in the practice. The fourth study, which is described in this report, was

  19. Evaluating the applicability of a semi-continuous aerosol sampler to measure Asian dust particles.

    PubMed

    Son, Se-Chang; Park, Seung Shik

    2015-03-01

    A Korean prototype semi-continuous aerosol sampler was used to measure Asian dust particles. During two dust-storm periods, concentrations of crustal and trace elements were significantly enriched. Dust storms are one of the most significant natural sources of air pollution in East Asia. The present study aimed to evaluate use of a Korean semi-continuous aerosol sampler (K-SAS) in observation of mineral dust particles during dust storm events. Aerosol slurry samples were collected at 60 min intervals using the K-SAS, which was operated at a sampling flow rate of 16.7 L min(-1) through a PM10 cyclone inlet. The measurements were made during dust storm events at an urban site, Gwangju in Korea, between April 30 and May 5, 2011. The K-SAS uses particle growth technology as a means of collecting atmospheric aerosol particles. Concentrations of 16 elements (Al, Fe, Mn, Ca, K, Cu, Zn, Pb, Cd, Cr, Ti, V, Ni, Co, As, and Se) were determined off-line in the collected slurry samples by inductively coupled plasma-mass spectrometry (ICP-MS). The sampling periods were classified into two types, based on the source regions of the dust storms and the transport pathways of the air masses reaching the sampling site. The first period "A" was associated with dust particles with high Ca content, originating from the Gobi desert regions of northern China and southern Mongolia. The second period "B" was associated with dust particles with low Ca content, originating from northeastern Chinese sandy deserts. The results from the K-SAS indicated noticeable differences in concentrations of crustal and trace elements in the two sampling periods, as a result of differences in the source regions of the dust storms, the air mass transport pathways, and the impact of smoke from forest fires. The concentrations of the crustal (Al, Ca, Ti, Mn, and Fe) and anthropogenic trace elements (Vi, Ni, Cu, Zn, As, Se, and Pb) were enriched significantly during the two dust storm periods. However, the

  20. Evaluating the applicability of a semi-continuous aerosol sampler to measure Asian dust particles.

    PubMed

    Son, Se-Chang; Park, Seung Shik

    2015-03-01

    A Korean prototype semi-continuous aerosol sampler was used to measure Asian dust particles. During two dust-storm periods, concentrations of crustal and trace elements were significantly enriched. Dust storms are one of the most significant natural sources of air pollution in East Asia. The present study aimed to evaluate use of a Korean semi-continuous aerosol sampler (K-SAS) in observation of mineral dust particles during dust storm events. Aerosol slurry samples were collected at 60 min intervals using the K-SAS, which was operated at a sampling flow rate of 16.7 L min(-1) through a PM10 cyclone inlet. The measurements were made during dust storm events at an urban site, Gwangju in Korea, between April 30 and May 5, 2011. The K-SAS uses particle growth technology as a means of collecting atmospheric aerosol particles. Concentrations of 16 elements (Al, Fe, Mn, Ca, K, Cu, Zn, Pb, Cd, Cr, Ti, V, Ni, Co, As, and Se) were determined off-line in the collected slurry samples by inductively coupled plasma-mass spectrometry (ICP-MS). The sampling periods were classified into two types, based on the source regions of the dust storms and the transport pathways of the air masses reaching the sampling site. The first period "A" was associated with dust particles with high Ca content, originating from the Gobi desert regions of northern China and southern Mongolia. The second period "B" was associated with dust particles with low Ca content, originating from northeastern Chinese sandy deserts. The results from the K-SAS indicated noticeable differences in concentrations of crustal and trace elements in the two sampling periods, as a result of differences in the source regions of the dust storms, the air mass transport pathways, and the impact of smoke from forest fires. The concentrations of the crustal (Al, Ca, Ti, Mn, and Fe) and anthropogenic trace elements (Vi, Ni, Cu, Zn, As, Se, and Pb) were enriched significantly during the two dust storm periods. However, the

  1. Statistical ranging of asteroid orbits: efficient MCMC and importance samplers

    NASA Astrophysics Data System (ADS)

    Virtanen, Jenni; Fedorets, Grigori; Granvik, Mikael; Oszkiewicz, Dagmara Anna; Muinonen, Karri

    2015-08-01

    We address the asteroid initial orbit computation problem by comparing various versions of the statistical ranging method (Virtanen et al. 2001, Muinonen et al. 2001) developed for exiguous observational data. In particular, the performance of the Markov-chain Monte Carlo (MCMC) ranging (Oszkiewicz et al. 2009) and the importance-sampler ranging methods, including the most recently developed random-walk ranging (Muinonen et al. 2015) are compared. We demonstrate the capabilities of the methods for various classes of asteroids, including near-Earth and main-belt asteroids, as well as transneptunian objects. We also study the performance of our statistical inverse methods as a function of increasing observational time interval, i.e., during the so-called phase transition. We also envision the application of the methods for space-debris orbits.Muinonen, K., Virtanen, J., Bowell, E., 2001. Collision probability for Earth-crossing asteroids using orbital ranging. Celestial Mechanics and Dynamical Astronomy 81, 93-101.Muinonen K., et al. 2015. Asteroid orbits from Gaia astrometry with random-walk statistical ranging, Planetary and Space Science, in preparation.Oszkiewicz, D., Muinonen, K., Virtanen, J., Granvik, M., 2009. Asteroid orbital ranging using Markov-chain Monte Carlo. Meteoritics and Planetary Science 44, 12, 1897-1904.Virtanen, J., Muinonen, K., Bowell, E., 2001. Statistical ranging of asteroid orbits. Icarus 154, 412-431.

  2. Progress Toward an Enceladus Amino Acid Sampler Astrobiology Instrument

    NASA Astrophysics Data System (ADS)

    Kirby, J. P.; Willis, P. A.; Blacksberg, J.

    2012-12-01

    The development of a new astrobiolgoy instrument for exploring the trace chemical composition of the Enceladus jets and plume, and the e-ring of Saturn is presented. The Enceladus amino acid sampler (EAAS) allows for detection of amino acids using optical Raman spectroscopy integrated with a sample pre-concentration system. The pre-concentration process facilitates the delivery of a sample to a mass spectrometer for detection of specific amino acids. The initial EAAS design utilizes lab-on-a-breadboard components where a sample inlet, sample outlet, reagents, controllers, pumps, valves and pre-concentration column for the EAAS prototype are all assembled on a 5" x 7" breadboard. The pre-concentration process is controlled using automation scripts and software. An optical window allows a Raman spectrometer to directly monitor the pre-concentration of amino acids in a filter/column loaded with of a strong cation exchange resin. Initial samples to demonstrate EAAS simulate the conditions of Don Juan Pond, one of the coldest and saltiest bodies of liquid water on Earth, located in the Wright Valley of Antarctica. This EAAS development is an important step toward a new type of astrobiology science instrument that is capable of operating on a spacecraft in flight or in orbit.

  3. Numerical evaluation of lateral diffusion inside diffusive gradients in thin films samplers.

    PubMed

    Santner, Jakob; Kreuzeder, Andreas; Schnepf, Andrea; Wenzel, Walter W

    2015-05-19

    Using numerical simulation of diffusion inside diffusive gradients in thin films (DGT) samplers, we show that the effect of lateral diffusion inside the sampler on the solute flux into the sampler is a nonlinear function of the diffusion layer thickness and the physical sampling window size. In contrast, earlier work concluded that this effect was constant irrespective of parameters of the sampler geometry. The flux increase caused by lateral diffusion inside the sampler was determined to be ∼8.8% for standard samplers, which is considerably lower than the previous estimate of ∼20%. Lateral diffusion is also propagated to the diffusive boundary layer (DBL), where it leads to a slightly stronger decrease in the mass uptake than suggested by the common 1D diffusion model that is applied for evaluating DGT results. We introduce a simple correction procedure for lateral diffusion and demonstrate how the effect of lateral diffusion on diffusion in the DBL can be accounted for. These corrections often result in better estimates of the DBL thickness (δ) and the DGT-measured concentration than earlier approaches and will contribute to more accurate concentration measurements in solute monitoring in waters.

  4. Numerical Evaluation of Lateral Diffusion Inside Diffusive Gradients in Thin Films Samplers

    PubMed Central

    2015-01-01

    Using numerical simulation of diffusion inside diffusive gradients in thin films (DGT) samplers, we show that the effect of lateral diffusion inside the sampler on the solute flux into the sampler is a nonlinear function of the diffusion layer thickness and the physical sampling window size. In contrast, earlier work concluded that this effect was constant irrespective of parameters of the sampler geometry. The flux increase caused by lateral diffusion inside the sampler was determined to be ∼8.8% for standard samplers, which is considerably lower than the previous estimate of ∼20%. Lateral diffusion is also propagated to the diffusive boundary layer (DBL), where it leads to a slightly stronger decrease in the mass uptake than suggested by the common 1D diffusion model that is applied for evaluating DGT results. We introduce a simple correction procedure for lateral diffusion and demonstrate how the effect of lateral diffusion on diffusion in the DBL can be accounted for. These corrections often result in better estimates of the DBL thickness (δ) and the DGT-measured concentration than earlier approaches and will contribute to more accurate concentration measurements in solute monitoring in waters. PMID:25877251

  5. Use of Passive Diffusion Samplers for Monitoring Volatile Organic Compounds in Ground Water

    USGS Publications Warehouse

    Harte, Philip T.; Brayton, Michael J.; Ives, Wayne

    2000-01-01

    Passive diffusion samplers have been tested at a number of sites where volatile organic compounds (VOC's) are the principal contaminants in ground water. Test results generally show good agreement between concentrations of VOC's in samples collected with diffusion samplers and concentrations in samples collected by purging the water from a well. Diffusion samplers offer several advantages over conventional and low-flow ground-water sampling procedures: * Elimination of the need to purge a well before collecting a sample and to dispose of contaminated water. * Elimination of cross-contamination of samples associated with sampling with non-dedicated pumps or sample delivery tubes. * Reduction in sampling time by as much as 80 percent of that required for 'purge type' sampling methods. * An increase in the frequency and spatial coverage of monitoring at a site because of the associated savings in time and money. The successful use of diffusion samplers depends on the following three primary factors: (1) understanding site conditions and contaminants of interest (defining sample objectives), (2) validating of results of diffusion samplers against more widely acknowledged sampling methods, and (3) applying diffusion samplers in the field.

  6. Optical bistability in symmetrically strained (GaIn)As/Ga(PAs) superlattices

    SciTech Connect

    Bastian, G.; von Plessen, G.; Feldmann, J.; Hader, J.; Marschner, T.; Stolz, W.; Goebel, E.O.

    1996-07-01

    We have studied the electroabsorptive properties of symmetrically strained (GaIn)As/Ga(PAs) superlattices consisting of 100 periods. Photocurrent measurements at 4 K reveal a pronounced pseudo-blue shift and a Wannier{endash}Stark splitting of the heavy-hole exciton transition. A self-electro-optic effect device has been realized which makes use of the pseudo-blue shift due to the Wannier{endash}Stark localization and of the transparency of the GaAs substrate. The self-electro-optic effect devices show on{endash}off contrast ratios of 2.1 at 77 K and of 1.3 at room temperature. {copyright} {ital 1996 American Institute of Physics.}

  7. A PAS domain-containing regulator controls flagella-flagella interactions in Campylobacter jejuni

    PubMed Central

    Reuter, Mark; Periago, Paula M.; Mulholland, Francis; Brown, Helen L.; van Vliet, Arnoud H. M.

    2015-01-01

    The bipolar flagella of the foodborne bacterial pathogen Campylobacter jejuni confer motility, which is essential for virulence. The flagella of C. jejuni are post-translationally modified, but how this process is controlled is not well understood. In this work, we have identified a novel PAS-domain containing regulatory system, which modulates flagella-flagella interactions in C. jejuni. Inactivation of the cj1387c gene, encoding a YheO-like PAS6 domain linked to a helix-turn-helix domain, resulted in the generation of a tightly associated “cell-train” morphotype, where up to four cells were connected by their flagella. The morphotype was fully motile, resistant to vortexing, accompanied by increased autoagglutination, and was not observed in aflagellated cells. The Δcj1387c mutant displayed increased expression of the adjacent Cj1388 protein, which comprises of a single endoribonuclease L-PSP domain. Comparative genomics showed that cj1387c (yheO) orthologs in bacterial genomes are commonly linked to an adjacent cj1388 ortholog, with some bacteria, including C. jejuni, containing another cj1388-like gene (cj0327). Inactivation of the cj1388 and cj0327 genes resulted in decreased autoagglutination in Tween-20-supplemented media. The Δcj1388 and Δcj0327 mutants were also attenuated in a Galleria larvae-based infection model. Finally, substituting the sole cysteine in Cj1388 for serine prevented Cj1388 dimerization in non-reducing conditions, and resulted in decreased autoagglutination in the presence of Tween-20. We hypothesize that Cj1388 and Cj0327 modulate post-translational modification of the flagella through yet unidentified mechanisms, and propose naming Cj1387 the Campylobacter Flagella Interaction Regulator CfiR, and the Cj1388 and Cj0327 protein as CfiP and CfiQ, respectively. PMID:26284050

  8. Plasticity of the PAS domain and a potential role for signal transduction in the histidine kinase DcuS.

    PubMed

    Etzkorn, Manuel; Kneuper, Holger; Dünnwald, Pia; Vijayan, Vinesh; Krämer, Jens; Griesinger, Christian; Becker, Stefan; Unden, Gottfried; Baldus, Marc

    2008-10-01

    The mechanistic understanding of how membrane-embedded sensor kinases recognize signals and regulate kinase activity is currently limited. Here we report structure-function relationships of the multidomain membrane sensor kinase DcuS using solid-state NMR, structural modeling and mutagenesis. Experimental data of an individual cytoplasmic Per-Arnt-Sim (PAS) domain were compared to structural models generated in silico. These studies, together with previous NMR work on the periplasmic PAS domain, enabled structural investigations of a membrane-embedded 40-kDa construct by solid-state NMR, comprising both PAS segments and the membrane domain. Structural alterations are largely limited to protein regions close to the transmembrane segment. Data from isolated and multidomain constructs favor a disordered N-terminal helix in the cytoplasmic domain. Mutations of residues in this region strongly influence function, suggesting that protein flexibility is related to signal transduction toward the kinase domain and regulation of kinase activity.

  9. Autophagosome formation can be achieved in the absence of Atg18 by expressing engineered PAS-targeted Atg2.

    PubMed

    Kobayashi, Takafumi; Suzuki, Kuninori; Ohsumi, Yoshinori

    2012-07-30

    The Atg2-Atg18 complex is essential for autophagosome formation in Saccharomyces cerevisiae. In this paper, we show that partial induction of autophagy can proceed in cells expressing engineered variants of Atg2 capable of localizing to the pre-autophagosomal structure (PAS) in the absence of Atg18. Specifically, through the construction of fusion proteins, we show that the fusion to Atg2 of either the phosphatidylinositol 3-phosphate-binding FYVE domain or the core autophagy protein Atg8 allowed limited Atg18-independent recovery of autophagosome formation. These results indicate that effective targeting of Atg2 to the PAS can compensate for loss of Atg18 function in autophagy.

  10. Ammonia concentration modeling based on retained gas sampler data

    SciTech Connect

    Terrones, G.; Palmer, B.J.; Cuta, J.M.

    1997-09-01

    The vertical ammonia concentration distributions determined by the retained gas sampler (RGS) apparatus were modeled for double-shell tanks (DSTs) AW-101, AN-103, AN-104, and AN-105 and single-shell tanks (SSTs) A-101, S-106, and U-103. One the vertical transport of ammonia in the tanks were used for the modeling. Transport in the non-convective settled solids and floating solids layers is assumed to occur primarily via some type of diffusion process, while transport in the convective liquid layers is incorporated into the model via mass transfer coefficients based on empirical correlations. Mass transfer between the top of the waste and the tank headspace and the effects of ventilation of the headspace are also included in the models. The resulting models contain a large number of parameters, but many of them can be determined from known properties of the waste configuration or can be estimated within reasonable bounds from data on the waste samples themselves. The models are used to extract effective diffusion coefficients for transport in the nonconvective layers based on the measured values of ammonia from the RGS apparatus. The modeling indicates that the higher concentrations of ammonia seen in bubbles trapped inside the waste relative to the ammonia concentrations in the tank headspace can be explained by a combination of slow transport of ammonia via diffusion in the nonconvective layers and ventilation of the tank headspace by either passive or active means. Slow transport by diffusion causes a higher concentration of ammonia to build up deep within the waste until the concentration gradients between the interior and top of the waste are sufficient to allow ammonia to escape at the same rate at which it is being generated in the waste.

  11. Passive samplers accurately predict PAH levels in resident crayfish.

    PubMed

    Paulik, L Blair; Smith, Brian W; Bergmann, Alan J; Sower, Greg J; Forsberg, Norman D; Teeguarden, Justin G; Anderson, Kim A

    2016-02-15

    Contamination of resident aquatic organisms is a major concern for environmental risk assessors. However, collecting organisms to estimate risk is often prohibitively time and resource-intensive. Passive sampling accurately estimates resident organism contamination, and it saves time and resources. This study used low density polyethylene (LDPE) passive water samplers to predict polycyclic aromatic hydrocarbon (PAH) levels in signal crayfish, Pacifastacus leniusculus. Resident crayfish were collected at 5 sites within and outside of the Portland Harbor Superfund Megasite (PHSM) in the Willamette River in Portland, Oregon. LDPE deployment was spatially and temporally paired with crayfish collection. Crayfish visceral and tail tissue, as well as water-deployed LDPE, were extracted and analyzed for 62 PAHs using GC-MS/MS. Freely-dissolved concentrations (Cfree) of PAHs in water were calculated from concentrations in LDPE. Carcinogenic risks were estimated for all crayfish tissues, using benzo[a]pyrene equivalent concentrations (BaPeq). ∑PAH were 5-20 times higher in viscera than in tails, and ∑BaPeq were 6-70 times higher in viscera than in tails. Eating only tail tissue of crayfish would therefore significantly reduce carcinogenic risk compared to also eating viscera. Additionally, PAH levels in crayfish were compared to levels in crayfish collected 10 years earlier. PAH levels in crayfish were higher upriver of the PHSM and unchanged within the PHSM after the 10-year period. Finally, a linear regression model predicted levels of 34 PAHs in crayfish viscera with an associated R-squared value of 0.52 (and a correlation coefficient of 0.72), using only the Cfree PAHs in water. On average, the model predicted PAH concentrations in crayfish tissue within a factor of 2.4 ± 1.8 of measured concentrations. This affirms that passive water sampling accurately estimates PAH contamination in crayfish. Furthermore, the strong predictive ability of this simple model suggests

  12. NASA/JPL hydrothermal vent bio-sampler

    NASA Astrophysics Data System (ADS)

    Jonsson, J.; Behar, A.; Bruckner, J.; Matthews, J.

    pagestyle empty begin document On the bottom of the oceans with volcanic activity present hydrothermal vents can be found which spew out mineral rich superheated water from the porous seafloor crust Some of these vents are situated several thousands of meters below the surface where the sunlight never reaches Yet life thrives here on the minerals and chemical compounds that the vent water brings up with it This chemosynthetic microbial community forms the basis of some of the most interesting ecosystems on our planet and could possibly also be found on other water rich planets and moons in the solar system Perhaps under the icy surface of the moon Europa there exist hydrothermal vents with such biota thriving independently of the solar energy The Hydrothermal Vent Bio-sampler HVB is a system which will be used to collect pristine samples of the water emanating from hydrothermal vents An array of temperature and flow sensors will monitor the sampling conditions This will allow for the samples to be collected from defined locations within the plume and the diversity and distribution of the chemosynthetic communities that might live there can be accurately described The samples will have to be taken without any contamination from the surrounding water thus the pristine requirement Monitoring the flow will assure that enough water has been sampled to account for the low biomass of these environments The system will be using a series of filters down to 0 2 mu m in pore size and the samples can be directly collected from the system for both culture-

  13. Multilevel samplers as microcosms to assess microbial response to biostimulation.

    PubMed

    Baldwin, B R; Peacock, A D; Park, M; Ogles, D M; Istok, J D; McKinley, J P; Resch, C T; White, D C

    2008-01-01

    Passive multilevel samplers (MLS) containing a solid matrix for microbial colonization were used as in situ microcosms in conjunction with a push-pull biostimulation experiment designed to promote biological U(VI) and Tc(VII) reduction. MLS were deployed at 24 elevations in the injection well and two downgradient wells to investigate the spatial variability in microbial community composition and growth prior to and following biostimulation. The microbial community was characterized by real-time quantitative polymerase chain reaction (Q-PCR) quantification of bacteria, NO(3)(-)-reducing bacteria (nirS and nirK), delta-proteobacteria, Geobacter sp., and methanogens (mcrA). Pretest cell densities were low overall but varied substantially with significantly greater bacterial populations detected at circumneutral pH (t-test, alpha= 0.05), suggesting carbon substrate and low pH limitations of microbial activity. Although pretest cell densities were low, denitrifying bacteria were dominant members of the microbial community. Biostimulation with an ethanol-amended ground water resulted in concurrent NO(3)(-) and Tc(VII) reduction, followed by U(VI) reduction. Q-PCR analysis of MLS revealed significant (1 to 2 orders of magnitude, Mann-Whitney U-test, alpha= 0.05) increases in cell densities of bacteria, denitrifiers, delta-proteobacteria, Geobacter sp., and methanogens in response to biostimulation. Traditionally, characterization of sediment samples has been used to investigate the microbial community response to biostimulation; however, collection of sediment samples is expensive and not conducive to deep aquifers or temporal studies. The results presented demonstrate that push-pull tests with passive MLS provide an inexpensive approach to determine the effect of biostimulation on contaminant concentrations, geochemical conditions, and the microbial community composition and function. PMID:18194316

  14. Multilevel Samplers to Assess Microbial Community Response to Biostimulation

    NASA Astrophysics Data System (ADS)

    Baldwin, B. R.; McKinley, J. P.; Peacock, A. D.; Park, M.; Ogles, D.; Istok, J. D.; Resch, C. T.; White, D. C.

    2006-05-01

    Passive multilevel samplers (MLS) containing a solid matrix for microbial colonization were used in conjunction with a push-pull biostimulation experiment designed to promote biological U(VI) and Tc(VII) reduction. MLS were deployed at 24 elevations in the injection well and two down gradient wells to investigate the spatial variability in microbial community composition and growth prior to and following biostimulation. The microbial community was characterized by real-time PCR (Q-PCR) quantification of eubacteria, NO3- reducing bacteria (nirS and nirK), δ-proteobacteria, Geobacter sp., and methanogens (mcrA). Pretest cell densities were low overall but varied substantially with significantly greater eubacterial populations detected at circumneutral pH (T-test, α=0.05) suggesting carbon substrate and low pH limitation of microbial activity. Although pretest cell densities were low, denitrifying bacteria were dominant members of the microbial community. Biostimulation with an ethanol amended groundwater resulted in concurrent NO3- and Tc(VII) reduction followed by U(VI) reduction. Q-PCR analysis of MLS revealed significant (1-2 orders of magnitude, T-test, α=0.05) increases in cell densities of eubacteria, denitrifiers, δ- proteobacteria, Geobacter sp., and methanogens in response to biostimulation. Traditionally characterization of sediment samples has been used to investigate the microbial community response to biostimulation, however, collection of sediment samples is expensive and not conducive to deep aquifers or temporal studies. The results presented demonstrate that push-pull tests with passive MLS provide an inexpensive approach to determine the effect of biostimulation on contaminant concentrations, geochemical conditions, and the microbial community composition and function.

  15. Multilevel samplers as microcosms to assess microbial response to biostimulation

    SciTech Connect

    Baldwin, Brett R.; Peacock, Aaron D.; Park, Melora M.; Ogles, Dora; Istok, Jonathan D.; McKinley, James P.; Resch, Charles T.; White, David C.

    2008-03-01

    Passive multilevel samplers (MLS) containing a solid matrix for microbial colonization were used in conjunction with a push-pull biostimulation experiment designed to promote biological U(VI) and Tc(VII) reduction. MLS were deployed at 24 elevations in the injection well and two down gradient wells to investigate the spatial variability in microbial community composition and growth prior to and following biostimulation. The microbial community was characterized by real-time PCR (Q-PCR) quantification of Bacteria, NO3- reducing bacteria (nirS and nirK), δ-proteobacteria, Geobacter sp., and methanogens (mcrA). Pretest cell densities were low overall but varied substantially with significantly greater Bacterial populations detected at circumneutral pH (T-test, α=0.05) suggesting carbon substrate and low pH limitations of microbial activity. Although pretest cell densities were low, denitrifying bacteria were dominant members of the microbial community. Biostimulation with an ethanol amended groundwater resulted in concurrent NO3- and Tc(VII) reduction followed by U(VI) reduction. Q-PCR analysis of MLS revealed significant (1-2 orders of magnitude, T-test, α=0.05) increases in cell densities of Bacteria, denitrifiers, δ-proteobacteria, Geobacter sp., and methanogens in response to biostimulation. Traditionally characterization of sediment samples has been used to investigate the microbial community response to biostimulation, however, collection of sediment samples is expensive and not conducive to deep aquifers or temporal studies. The results presented demonstrate that push-pull tests with passive MLS provide an inexpensive approach to determine the effect of biostimulation on contaminant concentrations, geochemical conditions, and the microbial community composition and function.

  16. Comparison of endotoxin and particle bounce in Marple cascade samplers with and without impaction grease.

    PubMed

    Kirychuk, Shelley P; Reynolds, Stephen J; Koehncke, Niels; Nakatsu, J; Mehaffy, John

    2009-01-01

    The health of persons engaged in agricultural activities are often related or associated with environmental exposures in their workplace. Accurately measuring, analyzing, and reporting these exposures is paramount to outcomes interpretation. This paper describes issues related to sampling air in poultry barns with a cascade impactor. Specifically, the authors describe how particle bounce can affect measurement outcomes and how the use of impaction grease can impact particle bounce and laboratory analyses such as endotoxin measurements. This project was designed to (1) study the effect of particle bounce in Marple cascade impactors that use polyvinyl chloride (PVC) filters; (2) to determine the effect of impaction grease on endotoxin assays when sampling poultry barn dust. A pilot study was undertaken utilizing six-stage Marple cascade impactors with PVC filters. Distortion of particulate size distributions and the effects of impaction grease on endotoxin analysis in samples of poultry dust distributed into a wind tunnel were studied. Although there was no significant difference in the overall dust concentration between utilizing impaction grease and not, there was a greater than 50% decrease in the mass median aerodynamic diameter (MMAD) values when impaction grease was not utilized. There was no difference in airborne endotoxin concentration or endotoxin MMAD between filters treated with impaction grease and those not treated. The results indicate that particle bounce should be a consideration when sampling poultry barn dust with Marple samplers containing PVC filters with no impaction grease. Careful consideration should be given to the utilization of impaction grease on PVC filters, which will undergo endotoxin analysis, as there is potential for interference, particularly if high or low levels of endotoxin are anticipated. PMID:19437284

  17. Design and testing of a new sampler for simplified vacuum-assisted headspace solid-phase microextraction.

    PubMed

    Yiantzi, Evangelia; Kalogerakis, Nicolas; Psillakis, Elefteria

    2016-07-13

    The design and testing of a new and low-cost experimental setup used for vacuum-assisted headspace solid-phase microextraction (Vac-HSSPME) is reported here. The device consists of a specially designed O-ring seal screw cap offering gas-tight seal to commercially available headspace vials. The new polytetrafluoroethylene (PTFE) cap was molded by a local manufacturer and had a hole that could tightly accommodate a septum. All operations were performed through the septum: air evacuation of the sampler, sample introduction and HSSPME sampling. The analytical performance of the new sampler was evaluated using 22 mL headspace vials with 9 mL water samples spiked with polychlorinated biphenyls (PCBs). Several experimental parameters were controlled and the optimized conditions were: 1000 rpm agitation speed; 30 min extraction time; 40 °C sampling temperature; polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber. The lack of accurate Henry's law constant (KH) values and information regarding how they change with temperature was a major limitation in predicting the phase location of evaporation resistance during Vac-HSSPME. Nevertheless, the combined effects of system conditions indicated the increasing importance of gas phase resistance with increasing degree of PCBs chlorination. Stirring enhancements were not recorded for the higher chlorinated PCBs suggesting that the hyperhydrophobic gas/water interface was the preferred location for these compounds. Analytically, the developed method was found to yield linear calibration curves with limits of detection in the sub ng L(-1) level and relative standard deviations ranging between 5.8 and 14%. To compensate for the low recoveries of the higher chlorinated PCB congeners in spiked river water the standard addition methodology was applied. Overall, the compact design of the new and reusable sample container allows efficient HSSPME sampling of organic analytes in water within short extraction times and at low sampling

  18. Design and testing of a new sampler for simplified vacuum-assisted headspace solid-phase microextraction.

    PubMed

    Yiantzi, Evangelia; Kalogerakis, Nicolas; Psillakis, Elefteria

    2016-07-13

    The design and testing of a new and low-cost experimental setup used for vacuum-assisted headspace solid-phase microextraction (Vac-HSSPME) is reported here. The device consists of a specially designed O-ring seal screw cap offering gas-tight seal to commercially available headspace vials. The new polytetrafluoroethylene (PTFE) cap was molded by a local manufacturer and had a hole that could tightly accommodate a septum. All operations were performed through the septum: air evacuation of the sampler, sample introduction and HSSPME sampling. The analytical performance of the new sampler was evaluated using 22 mL headspace vials with 9 mL water samples spiked with polychlorinated biphenyls (PCBs). Several experimental parameters were controlled and the optimized conditions were: 1000 rpm agitation speed; 30 min extraction time; 40 °C sampling temperature; polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber. The lack of accurate Henry's law constant (KH) values and information regarding how they change with temperature was a major limitation in predicting the phase location of evaporation resistance during Vac-HSSPME. Nevertheless, the combined effects of system conditions indicated the increasing importance of gas phase resistance with increasing degree of PCBs chlorination. Stirring enhancements were not recorded for the higher chlorinated PCBs suggesting that the hyperhydrophobic gas/water interface was the preferred location for these compounds. Analytically, the developed method was found to yield linear calibration curves with limits of detection in the sub ng L(-1) level and relative standard deviations ranging between 5.8 and 14%. To compensate for the low recoveries of the higher chlorinated PCB congeners in spiked river water the standard addition methodology was applied. Overall, the compact design of the new and reusable sample container allows efficient HSSPME sampling of organic analytes in water within short extraction times and at low sampling

  19. Sampling and Analyzing Air Pollution: An Apparatus Suitable for Use in Schools.

    ERIC Educational Resources Information Center

    Rockwell, Dean M.; Hansen, Tony

    1994-01-01

    Describes two variations of an air sampler and analyzer that are inexpensive to construct, easy to operate, and designed to be used in an educational program. Variations use vacuum cleaners and aquarium pumps, and white facial tissues serve as filters. Samples of air pollution obtained by this method may be used from early grade school to advanced…

  20. An Introduction to the DA-T Gibbs Sampler for the Two-Parameter Logistic (2PL) Model and beyond

    ERIC Educational Resources Information Center

    Maris, Gunter; Bechger, Timo M.

    2005-01-01

    The DA-T Gibbs sampler is proposed by Maris and Maris (2002) as a Bayesian estimation method for a wide variety of "Item Response Theory (IRT) models". The present paper provides an expository account of the DA-T Gibbs sampler for the 2PL model. However, the scope is not limited to the 2PL model. It is demonstrated how the DA-T Gibbs sampler for…

  1. Long-term integrating samplers for indoor air and sub slab soil gas at VI sites

    EPA Science Inventory

    Vapor intrusion (VI) site assessments are plagued by substantial spatial and temporal variability that makes exposure and risk assessment difficult. Most risk-based decision making for volatile organic compound (VOC) exposure in the indoor environment is based on health benchmark...

  2. optGpSampler: An Improved Tool for Uniformly Sampling the Solution-Space of Genome-Scale Metabolic Networks

    PubMed Central

    Megchelenbrink, Wout; Huynen, Martijn; Marchiori, Elena

    2014-01-01

    Constraint-based models of metabolic networks are typically underdetermined, because they contain more reactions than metabolites. Therefore the solutions to this system do not consist of unique flux rates for each reaction, but rather a space of possible flux rates. By uniformly sampling this space, an estimated probability distribution for each reaction’s flux in the network can be obtained. However, sampling a high dimensional network is time-consuming. Furthermore, the constraints imposed on the network give rise to an irregularly shaped solution space. Therefore more tailored, efficient sampling methods are needed. We propose an efficient sampling algorithm (called optGpSampler), which implements the Artificial Centering Hit-and-Run algorithm in a different manner than the sampling algorithm implemented in the COBRA Toolbox for metabolic network analysis, here called gpSampler. Results of extensive experiments on different genome-scale metabolic networks show that optGpSampler is up to 40 times faster than gpSampler. Application of existing convergence diagnostics on small network reconstructions indicate that optGpSampler converges roughly ten times faster than gpSampler towards similar sampling distributions. For networks of higher dimension (i.e. containing more than 500 reactions), we observed significantly better convergence of optGpSampler and a large deviation between the samples generated by the two algorithms. Availability: optGpSampler for Matlab and Python is available for non-commercial use at: http://cs.ru.nl/~wmegchel/optGpSampler/. PMID:24551039

  3. Minor-bodies science with the J-PAS/J-PLUS photometric surveys

    NASA Astrophysics Data System (ADS)

    De Prá, M.; Carvano, J.

    2014-07-01

    The JPAS/J-PLUS is a joint Spanish-Brazilian project that aims to map an area of the sky of 8000 square degrees, in order to measure, with unprecedented accuracy, the redshifts of a large sample of extragalactic objects up magnitude 23. It involves the installation of two telescopes on the Javalambre Mountains, in Spain. The T250 telescope will have an aperture of 250 cm and will be equipped with a camera with a 3 square degree field of view and will use a set of 56 filters (54 narrow band + 2 wide band) covering the 0.3--1.0 micron range, while the T80 telescope (presently on commissioning phase) will have a camera with 2 square degree field of view and will use a set of 12 narrow and intermediate band filters covering the same wavelength range. During its execution, the surveys will also observe a large number of minor Solar System bodies. For those objects, the differential of JPAS/J-PLUS with respect to other large photometric survey is the number and position of the filters used, which will allow a better identification of some taxonomic classes that are not well defined only with SDSS-like filter systems. In particular, the JPAS/J-PLUS data set will allow a robust identification of the 0.7 micron water alteration band that characterize the Ch class in Bus taxonomy. Thus, with JPAS/J-PLUS it will be possible to map the occurrence of water alteration in the present Solar System, which in turn will allow us to put further constraints of the presence of volatiles and of heating processes in the early Solar System. Also, although the survey cadence is not optimized for the discovery of minor bodies, J-PAS/J-PLUS can give an important contribution to the effort of expanding the known population of asteroids and TNOs. We will discuss also the expected efficiency of the J-PLUS/J-PAS surveys in finding minor bodies.

  4. The Bag-Sampler: A Simple Device for Collecting Zooplankton in Shallow Vegetated Ponds

    NASA Astrophysics Data System (ADS)

    Frisch, Dagmar; Wohltmann, Andreas

    2005-12-01

    Zooplankton in temporary ponds is often collected with gear originally designed for lakes, and mostly unsuitable for sampling shallow habitats. We describe a new simple and inexpensive device for sampling zooplankton in very shallow, vegetated temporary ponds. We tested the sampling efficiency by comparing species composition and density of cyclopoid copepods, an important component of the zooplankton, by sampling with both the new bag sampler and a plastic beaker frequently employed for collections of zooplankton in small waterbodies. With the bag sampler we collected a larger number of species and higher densities of copepods due to its higher efficiency in vegetated areas and near the sediment. The beaker appeared to sample almost only the water surface. The samples collected with the bag sampler revealed a distinct distribution of copepod life cycle stages in a shallow pond, which differed between depths and microhabitats. Additional advantages of the bag sampler are its small size and weight, and the possibility of fast exchange of sample bags between sample locations, thus preventing accidental faunal exchange between sample locations. We conclude that the bag sampler is a device especially useful for sampling zooplankton of shallow ponds and wetlands rich in vegetation, for diversity studies as well as for quantitative sampling.

  5. Polar organic chemical integrative samplers for pesticides monitoring: impacts of field exposure conditions.

    PubMed

    Lissalde, Sophie; Mazzella, Nicolas; Mazellier, Patrick

    2014-08-01

    This study focuses on how Polar Organic Chemical Integrative Samplers (POCIS) work in real environmental conditions. A selection of 23 polar pesticides and 8 metabolites were investigated by exposure of triplicates of integrative samplers in two rivers in France for successive 14-day periods. The pesticides and metabolites were trapped not only in Oasis HLB sorbent but also in the polyethersulfone (PES) membrane of the POCIS. The distribution of pesticides depended on the molecular structure. The use of the Performance Reference Compound (PRC) is also discussed here. The impact of some environmental parameters and exposure setup on the transfer of pesticides in POCIS sorbent was studied: river flow rate, biofouling on membranes, sampler holding design and position in the stream. Results show a significant impact of river flow velocity on PRC desorption, especially for values higher than 4 cm·s(-1). Some fouling was observed on the PES membrane which could potentially have an impact on molecule accumulation in the POCIS. Finally, the positioning of the sampler in the river did not have significant effects on pesticide accumulation, when perpendicular exposures were used (sampler positioning in front of the water flow). The POCIS with PRC correction seems to be a suitable tool for estimating time-weighted average (TWA) concentrations, for all the molecules except for one of the nine pesticides analyzed in these two French rivers.

  6. Construction and testing of a simple and economical soil greenhouse gas automatic sampler

    USGS Publications Warehouse

    Ginting, D.; Arnold, S.L.; Arnold, N.S.; Tubbs, R.S.

    2007-01-01

    Quantification of soil greenhouse gas emissions requires considerable sampling to account for spatial and/or temporal variation. With manual sampling, additional personnel are often not available to sample multiple sites within a narrow time interval. The objectives were to construct an automatic gas sampler and to compare the accuracy and precision of automatic versus manual sampling. The automatic sampler was tested with carbon dioxide (CO2) fluxes that mimicked the range of CO2 fluxes during a typical corn-growing season in eastern Nebraska. Gas samples were drawn from the chamber at 0, 5, and 10 min manually and with the automatic sampler. The three samples drawn with the automatic sampler were transferred to pre-vacuumed vials after 1 h; thus the samples in syringe barrels stayed connected with the increasing CO2 concentration in the chamber. The automatic sampler sustains accuracy and precision in greenhouse gas sampling while improving time efficiency and reducing labor stress. Copyright ?? Taylor & Francis Group, LLC.

  7. Chemical and toxicologic assessment of organic contaminants in surface water using passive samplers

    USGS Publications Warehouse

    Alvarez, D.A.; Cranor, W.L.; Perkins, S.D.; Clark, R.C.; Smith, S.B.

    2008-01-01

    Passive sampling methodologies were used to conduct a chemical and toxicologic assessment of organic contaminants in the surface waters of three geographically distinct agricultural watersheds. A selection of current-use agrochemicals and persistent organic pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides, were targeted using the polar organic chemical integrative sampler (POCIS) and the semipermeable membrane device passive samplers. In addition to the chemical analysis, the Microtox assay for acute toxicity and the yeast estrogen screen (YES) were conducted as potential assessment tools in combination with the passive samplers. During the spring of 2004, the passive samplers were deployed for 29 to 65 d at Leary Weber Ditch, IN; Morgan Creek, MD; and DR2 Drain, WA. Chemical analysis of the sampler extracts identified the agrochemicals predominantly used in those areas, including atrazine, simazine, acetochlor, and metolachlor. Other chemicals identified included deethylatrazine and deisopropylatrazine, trifluralin, fluoranthene, pyrene, cis- and trans-nonachlor, and pentachloroanisole. Screening using Microtox resulted in no acutely toxic samples. POCIS samples screened by the YES assay failed to elicit a positive estrogenic response. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  8. The Psychiatric Assessment Schedule for Adult with Developmental Disability (PAS-ADD) Checklist: Reliability and Validity of French Version

    ERIC Educational Resources Information Center

    Gerber, F.; Carminati, G. Galli

    2013-01-01

    Background: The lack of psychometric measures of psychopathology especially in intellectual disabilities (ID) population was addressed by creation of the Psychiatric Assessment Schedule for Adult with Developmental Disability (PAS-ADD-10) in Moss et?al. This schedule is a structured interview designed for professionals in psychopathology. The…

  9. Safety evaluation for packaging for the transport of K Basin sludge samples in the PAS-1 cask

    SciTech Connect

    SMITH, R.J.

    1998-11-17

    This safety evaluation for packaging authorizes the shipment of up to two 4-L sludge samples to and from the 325 Lab or 222-S Lab for characterization. The safety of this shipment is based on the current U.S. Department of Energy Certification of Compliance (CoC) for the PAS-1 cask, USA/9184/B(U) (DOE).

  10. Biological control of Aeromonas salmonicida subsp. salmonicida infection in rainbow trout (Oncorhynchus mykiss) using Aeromonas phage PAS-1.

    PubMed

    Kim, J H; Choresca, C H; Shin, S P; Han, J E; Jun, J W; Park, S C

    2015-02-01

    The potential control efficacy of Aeromonas phage PAS-1 was evaluated against Aeromonas salmonicida subsp. salmonicida infection in rainbow trout (Oncorhynchus mykiss) model in this study. The phage was co-cultured with the virulent A. salmonicida subsp. salmonicida strain AS05 that possesses the type III secretion system (TTSS) ascV gene, and efficient bacteriolytic activity was observed against the bacteria. The administration of PAS-1 in rainbow trout demonstrated that the phage was cleared from the fish within 200 h post-administration, and a temporal neutralizing activity against the phage was detected in the sera of phage-administrated fish. The administration of PAS-1 (multiplicity of infection: 10 000) in A. salmonicida subsp. salmonicida infected rainbow trout model showed notable protective effects, with increased survival rates and mean times to death. These results demonstrated that Aeromonas phage PAS-1 could be considered as an alternative biological control agent against A. salmonicida subsp. salmonicida infections in rainbow trout culture.

  11. An animal model of type A cystinuria due to spontaneous mutation in 129S2/SvPasCrl mice.

    PubMed

    Livrozet, Marine; Vandermeersch, Sophie; Mesnard, Laurent; Thioulouse, Elizabeth; Jaubert, Jean; Boffa, Jean-Jacques; Haymann, Jean-Philippe; Baud, Laurent; Bazin, Dominique; Daudon, Michel; Letavernier, Emmanuel

    2014-01-01

    Cystinuria is an autosomal recessive disease caused by the mutation of either SLC3A1 gene encoding for rBAT (type A cystinuria) or SLC7A9 gene encoding for b0,+AT (type B cystinuria). Here, we evidenced in a commonly used congenic 129S2/SvPasCrl mouse substrain a dramatically high frequency of kidney stones that were similar to those of patients with cystinuria. Most of 129S2/SvPasCrl exhibited pathognomonic cystine crystals in urine and an aminoaciduria profile similar to that of patients with cystinuria. In addition, we observed a heterogeneous inflammatory infiltrate and cystine tubular casts in the kidney of cystinuric mice. As compared to another classical mouse strain, C57BL/6J mice, 129S2/SvPasCrl mice had an increased mortality associated with bilateral obstructive hydronephrosis. In 129S2/SvPasCrl mice, the heavy subunit rBAT of the tetrameric transporter of dibasic amino acids was absent in proximal tubules and we identified a single pathogenic mutation in a highly conserved region of the Slc3a1 gene. This novel mouse model mimicking human disease would allow us further pathophysiological studies and may be useful to analyse the crystal/tissue interactions in cystinuria. PMID:25048459

  12. Morphological Evaluation of Proximal Anastomosis by PAS-Port® System in Patients with Long-Term Patent Grafts

    PubMed Central

    Fujii, Takeshiro; Hara, Masanori; Sasaki, Yuki; Katayanagi, Tomoyuki; Okuma, Shinnosuke; Watanabe, Yoshinori

    2014-01-01

    Purpose: We examined grafts employing for morphological analysis of early and long-term results on proximal anastomosis with the PAS-Port®. Methods: One hundred and four patients treated by OPCAB with PAS-Port® were performed postoperative MDCT. Morphological evaluation of the proximal anastomotic region was classified into three groups (A; graft was anastomosed almost perpendicularly to the aortic wall, B; graft was same type A, but subsequently curved to form an acute angle with the aortic wall, C; graft take off acute angle with the aortic wall) evaluated on planar and sagittal sections. Results: One hundred twenty-six PAS-Port® were used. Patency rate was 99.0% at discharge, 94.7% at 1 year, and no blockages were detected thereafter in patients examined. The morphology rate was A 50.6%, B 15.3% and C 34.1% on planar sections, and A 58.8%, B 10.6% and C 30.6% on sagittal sections. Conclusion: The morphological evaluation of grafts revealed the degree of freedom in graft design to be relatively high and long-term patency posed no particular problem even if the layout of the proximal anastomotic region involved a relatively acute angle. The PAS-Port® was considered to be a highly reliable device which performed appropriate proximal anastomosis and improved the patency of vein grafting to the aortic wall. PMID:25078547

  13. Toxins vapC and pasB from prokaryotic TA modules remain active in mammalian cancer cells.

    PubMed

    Wieteska, Łukasz; Skulimowski, Aleksander; Cybula, Magdalena; Szemraj, Janusz

    2014-10-01

    Among the great number of addictive modules which have been discovered, only a few have been characterized. However, research concerning the adoption of toxins from these systems shows their great potential as a tool for molecular biology and medicine. In our study, we tested two different toxins derived from class II addictive modules, pasAB from plasmid pTF-FC2 (Thiobacillus ferrooxidans) and vapBC 2829Rv (Mycobacterium tuberculosis), in terms of their usefulness as growth inhibitors of human cancer cell lines, namely KYSE 30, MCF-7 and HCT 116. Transfection of the pasB and vapC genes into the cells was conducted with the use of two different expression systems. Cellular effects, such as apoptosis, necrosis and changes in the cell cycle, were tested by applying flow cytometry with immunofluorescence staining. Our findings demonstrated that toxins VapC and PasB demonstrate proapoptotic activity in the human cancer cells, regardless of the expression system used. As for the toxin PasB, observed changes were more subtle than for the VapC. The level of expression for both the genes was monitored by QPCR and did not reveal statistically significant differences within the same cell line.

  14. Solvent-free sampling with di-n-butylamine for monitoring of isocyanates in air.

    PubMed

    Marand, Asa; Karlsson, Daniel; Dalene, Marianne; Skarping, Gunnar

    2005-04-01

    The solvent-free sampler for airborne isocyanates consisted of a polypropylene tube with an inner wall coated with a glass fibre filter, coupled in series with a 13 mm glass fibre filter. The filters were impregnated with reagent solution containing equimolar amounts of di-n-butylamine (DBA) and acetic acid. Air sampling was performed with an air flow of 0.2 l min(-1). The formed isocyanate-DBA derivatives were determined using liquid chromatography and tandem mass spectrometry. The sampler was investigated in regard to collection principle and extraction of the formed derivatives with good results. The possibility to store the sampler before sampling and to perform long-term sampling was demonstrated. Field extraction of the sampler was not necessary, as there was no difference between immediately extracted samples and stored ones (2 days). In comparative studies, the sampler was evaluated against a reference method, impinger-filter sampling with DBA as reagent. The ratios between the results obtained with the sampler and the reference in a test chamber at a relative humidity (RH) of 45% was in the range of 83-109% for isocyanates formed during thermal decomposition of PUR. At RH 95%, the range was 72-101% with the exception of isocyanic acid. In two field evaluations, the ratios for fast curing 2,4'- and 4,4'-methylene bisphenyl diisocyanate (MDI) was in the range 81-113% and for the 3-ring MDI the range was 54-70%. For the slower curing 1,6-hexamethylene diisocyanate (HDI) and HDI isocyanurate, the ratios were in the range 78-145%. In conclusion, the solvent-free sampler is a convenient alternative in most applications to the more cumbersome impinger-filter sampler.

  15. Passive samplers accurately predict PAH levels in resident crayfish.

    PubMed

    Paulik, L Blair; Smith, Brian W; Bergmann, Alan J; Sower, Greg J; Forsberg, Norman D; Teeguarden, Justin G; Anderson, Kim A

    2016-02-15

    Contamination of resident aquatic organisms is a major concern for environmental risk assessors. However, collecting organisms to estimate risk is often prohibitively time and resource-intensive. Passive sampling accurately estimates resident organism contamination, and it saves time and resources. This study used low density polyethylene (LDPE) passive water samplers to predict polycyclic aromatic hydrocarbon (PAH) levels in signal crayfish, Pacifastacus leniusculus. Resident crayfish were collected at 5 sites within and outside of the Portland Harbor Superfund Megasite (PHSM) in the Willamette River in Portland, Oregon. LDPE deployment was spatially and temporally paired with crayfish collection. Crayfish visceral and tail tissue, as well as water-deployed LDPE, were extracted and analyzed for 62 PAHs using GC-MS/MS. Freely-dissolved concentrations (Cfree) of PAHs in water were calculated from concentrations in LDPE. Carcinogenic risks were estimated for all crayfish tissues, using benzo[a]pyrene equivalent concentrations (BaPeq). ∑PAH were 5-20 times higher in viscera than in tails, and ∑BaPeq were 6-70 times higher in viscera than in tails. Eating only tail tissue of crayfish would therefore significantly reduce carcinogenic risk compared to also eating viscera. Additionally, PAH levels in crayfish were compared to levels in crayfish collected 10 years earlier. PAH levels in crayfish were higher upriver of the PHSM and unchanged within the PHSM after the 10-year period. Finally, a linear regression model predicted levels of 34 PAHs in crayfish viscera with an associated R-squared value of 0.52 (and a correlation coefficient of 0.72), using only the Cfree PAHs in water. On average, the model predicted PAH concentrations in crayfish tissue within a factor of 2.4 ± 1.8 of measured concentrations. This affirms that passive water sampling accurately estimates PAH contamination in crayfish. Furthermore, the strong predictive ability of this simple model suggests

  16. The MAGIC Meteoric Smoke Particle Sampler - Description and Results

    NASA Astrophysics Data System (ADS)

    Hedin, J.

    2013-12-01

    properties is by direct collection followed by detailed laboratory analysis. However, the sounding rocket approach, which is the only practical method to carry out a sampling experiment at the desired mesospheric altitudes, is subject to critical limitations imposed by aerodynamics. As nanometer size particles tend to follow the airflow around the rocket payload structure, their sampling is a substantial experimental challenge. The objective of the MAGIC project (Mesospheric Aerosol - Genesis, Interaction and Composition) was to design and build an instrument to directly sample meteoric smoke particles in the mesosphere and return them to ground for detailed laboratory investigations. Here we describe the MAGIC meteoric smoke particle sampler and present attempts to directly sample MSPs and the challenges and uncertainties in the sampling procedure.

  17. An accurate cluster selection function for the J-PAS narrow-band wide-field survey

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Benítez, N.; Dupke, R.; Cypriano, E.; Lima-Neto, G.; López-Sanjuan, C.; Varela, J.; Alcaniz, J. S.; Broadhurst, T.; Cenarro, A. J.; Devi, N. Chandrachani; Díaz-García, L. A.; Fernandes, C. A. C.; Hernández-Monteagudo, C.; Mei, S.; Mendes de Oliveira, C.; Molino, A.; Oteo, I.; Schoenell, W.; Sodré, L.; Viironen, K.; Marín-Franch, A.

    2016-03-01

    The impending Javalambre Physics of the accelerating Universe Astrophysical Survey (J-PAS) will be the first wide-field survey of ≳ 8500 deg2 to reach the `stage IV' category. Because of the redshift resolution afforded by 54 narrow-band filters, J-PAS is particularly suitable for cluster detection in the range z<1. The photometric redshift dispersion is estimated to be only ˜0.003 with few outliers ≲4 per cent for galaxies brighter than i ˜ 23 AB, because of the sensitivity of narrow band imaging to absorption and emission lines. Here, we evaluate the cluster selection function for J-PAS using N-body+semi-analytical realistic mock catalogues. We optimally detect clusters from this simulation with the Bayesian Cluster Finder, and we assess the completeness and purity of cluster detection against the mock data. The minimum halo mass threshold we find for detections of galaxy clusters and groups with both >80 per cent completeness and purity is Mh ˜ 5 × 1013 M⊙ up to z ˜ 0.7. We also model the optical observable, M^{*}_CL-halo mass relation, finding a non-evolution with redshift and main scatter of σ _{M^{*}_CL | M_h}˜ 0.14 dex down to a factor 2 lower in mass than other planned broad-band stage IV surveys, at least. For the Mh ˜ 1 × 1014 M⊙ Planck mass limit, J-PAS will arrive up to z ˜ 0.85 with a σ _{M^{*}_CL | M_h}˜ 0.12 dex. Therefore, J-PAS will provide the largest sample of clusters and groups up to z ˜ 0.8 with a mass calibration accuracy comparable to X-ray data.

  18. Wheeling à petit pas: Parkinsonism detected by observation of wheelchair propulsion.

    PubMed

    Worley, Scott W; Kirby, R Lee; MacLeod, Donald A

    2006-11-01

    We present a man with parkinsonism detected by the observation of wheelchair propulsion. His manual wheelchair propulsion technique was observed to include rapid, brief, low-power strokes resembling the marche à petit pas (walking with tiny steps) phenomenon of parkinsonism. We videotaped his wheelchair propulsion and compared him with ten age-, gender-, and diagnosis-matched controls. The patient had a propulsion velocity of 0.14 m/sec compared with a mean (+/- standard deviation) of 0.73 (+/- 0.16) m/sec for the controls, a cadence of 209 strokes/min vs. 60 (+/- 12) strokes/min for the controls, and a mechanical efficiency of 0.04 m/stroke compared with 0.75 (+/- 0.25) m/stroke for the controls. This observation shifted the course of his medical investigations and management as well as his rehabilitation care. This is the first detailed report of how parkinsonian features may affect manual wheelchair propulsion. It suggests that observation of wheelchair mobility should be a routine component of the physical examination of wheelchair users. PMID:17079968

  19. iPAS: AES Flight System Technology Maturation for Human Spaceflight

    NASA Technical Reports Server (NTRS)

    Othon, William L.

    2014-01-01

    In order to realize the vision of expanding human presence in space, NASA will develop new technologies that can enable future crewed spacecraft to go far beyond Earth orbit. These technologies must be matured to the point that future project managers can accept the risk of incorporating them safely and effectively within integrated spacecraft systems, to satisfy very challenging mission requirements. The technologies must also be applied and managed within an operational context that includes both on-board crew and mission support on Earth. The Advanced Exploration Systems (AES) Program is one part of the NASA strategy to identify and develop key capabilities for human spaceflight, and mature them for future use. To support this initiative, the Integrated Power Avionics and Software (iPAS) environment has been developed that allows engineers, crew, and flight operators to mature promising technologies into applicable capabilities, and to assess the value of these capabilities within a space mission context. This paper describes the development of the integration environment to support technology maturation and risk reduction, and offers examples of technology and mission demonstrations executed to date.

  20. Involvement of inhibitory PAS domain protein in neuronal cell death in Parkinson’s disease

    PubMed Central

    Torii, S; Kasai, S; Suzuki, A; Todoroki, Y; Yokozawa, K; Yasumoto, K-I; Seike, N; Kiyonari, H; Mukumoto, Y; Kakita, A; Sogawa, K

    2015-01-01

    Inhibitory PAS domain protein (IPAS), a repressor of hypoxia-inducible factor-dependent transcription under hypoxia, was found to exert pro-apoptotic activity in oxidative stress-induced cell death. However, physiological and pathological processes associated with this activity are not known. Here we show that IPAS is a key molecule involved in neuronal cell death in Parkinson’s disease (PD). IPAS was ubiquitinated by Parkin for proteasomal degradation following carbonyl cyanide m-chlorophenyl hydrazone treatment. Phosphorylation of IPAS at Thr12 by PTEN-induced putative kinase 1 (PINK1) was required for ubiquitination to occur. Activation of the PINK1–Parkin pathway attenuated IPAS-dependent apoptosis. IPAS was markedly induced in the midbrain following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration, and IPAS-deficient mice showed resistance to MPTP-induced degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). A significant increase in IPAS expression was found in SNpc neurons in patients with sporadic PD. These results indicate a mechanism of neurodegeneration in PD. PMID:27551449