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Sample records for dust samplers preliminary

  1. Differences in particle size distributions collected by two wood dust samplers: preliminary findings

    International Nuclear Information System (INIS)

    Campopiano, A.; Olori, A.; Basili, F.; Ramires, D.; Zakrzewska, A.M.

    2008-01-01

    The International Agency for Research on Cancer (IARC) classification of wood dust as carcinogenic to humans, and the threshold limit value (TLV) of 5 mg/m 3 weighted over an 8-hour work day as defined by Italian legislation, have raised the issue of dust risk assessments in all woodworking environments. The aim is to characterize the particle size distribution for wood particles collected by two samplers used for collecting the inhalable fraction: the IOM sampler (Institute of Occupational Medicine, Edinburgh, Scotland) and the conical sampler also known in Italy as conetto. These two sampling heads were chosen mainly because the Italian conical sampler, used in the past for total dust sampling, is the most widely used by the Italian Prevention Services and analysis laboratories in general, whereas the IOM sampler was specifically designed to collect the inhalable fraction of airborne particles. The devices were placed side by side within the worker's breathing zone. In addition, another IOM sampler not connected to the personal sampling pump was placed on the same worker, thus functioning as a passive sampler capable of collecting projectile particles normally produced during processing. A Scanning Electron Microscope (SEM) coupled with energy dispersive X-ray spectrometry (EDAX) was used to count the number of particles collected on the sampling filters. The size of each particle identified by the SEM was determined by measuring its mean diameter. The SEM analysis revealed that the average size of the largest particles collected by the conetto sampler did not exceed 150 μm, whereas the size of particles collected by the IOM sampler was up to 350 μm. Indeed, the analysis of the filters of the passive IOM samplers showed that particles with mean diameters larger than 100 μm were collected, although the calculated percentage was very low (on average, approximately 1%). This does not mean that their gravimetric contribution is negligible; indeed, the weight of

  2. 30 CFR 74.5 - Tests of coal mine dust personal sampler units.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests of coal mine dust personal sampler units... Personal Sampler Unit § 74.5 Tests of coal mine dust personal sampler units. (a) The National Institute for... tests and evaluations to determine whether the pump unit of a CMDPSU that is submitted for approval...

  3. The effects of ambient conditions on the passive dust sampler when used in coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Hemingway, M.; Thorpe, A.

    1998-09-01

    A previous feasibility study of the Health and Safety Laboratory (HSL) electret-based passive dust sampler carried out during site sampling in coal mines showed that the measurements made with the passive sampler and those made with the MRE sampler correlated well in each of two mines, but the ratios of samples obtained with the passive sampler and the MRE sampler in the two mines were different. This means the passive sampler would need a separate calibration for each coal mine in which it was used. Laboratory tests and further underground trials were carried out to quantify the possible effects of temperature and humidity on ratios. The passive dust samplers used at Maltby Colliery in the UK were found to pass the acceptance criteria according to the CEN standard for the assessment of the performance of instruments for the measurement of airborne particles, provided that samplers exposed when coal was not being cut were not included in the analysis. Temperature and relative humidity slightly affected the behaviour of the passive sampler during laboratory trials and relative humidity was found to possibly affect the behaviour during field trials. Ventilation rates had no effect on the passive sampler behaviour but the orientation of the passive dust sampler with respect to air flow affected the behaviour during laboratory trials. Further work is needed to quantify effects. 7 refs., 14 figs., 3 tabs.

  4. Accuracy criteria recommended for the certification of gravimetric coal-mine-dust samplers

    International Nuclear Information System (INIS)

    Bowman, J.D.; Bartley, D.L.; Breuer, G.M.; Doemeny, L.J.; Murdock, D.J.

    1984-07-01

    Procedures for testing bias and precision of gravimetric coal-mine-dust sampling units are reviewed. Performance criteria for NIOSH certification of personal coal-mine dust samplers are considered. The NIOSH criterion is an accuracy of 25% at the 95% confidence interval. Size distributions of coal-mine-dust are discussed. Methods for determining size distributions are described. Sampling and sizing methods are considered. Cyclone parameter estimation is discussed. Bias computations for general sampling units are noted. Recommended procedures for evaluating bias and precision of gravimetric coal mine dust personal samplers are given. The authors conclude that when cyclones are operated at lower rates, the NIOSH accuracy criteria can be met

  5. Project R43.106: Field trails of a passive dust sampler in mines: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hemingway, M. [Health and Safety Laboratory, Sheffield (United Kingdom). Environmental Measurement Groups

    1999-12-01

    Electret based passive dust samplers developed by the project were tested in four collieries in the United Kingdom and compared with MRE gravimetric site samplers (Casella type 113A) and CIP10 samplers (Capteur Indivuel de Poussiere 10 made by Arelco, France). Results of site sampling and personal sampling was assessed according to the draft-CFB standard (1998). The sampler did not satisfy the CEN criteria when results from all the collieries were analysed and therefore a general calibration function suitable for all mines could not be used. In the severe conditions of the coal mines, 62% of the passive samplers failed because the electrets lost more than 70% of their initial surface charge. Work is recommended on improving the charge stability of the electrets. 7 refs., 6 figs., 1 app.

  6. Field trials of an electret based passive dust sampler in coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Hemingway, M.A.; Brown, R.C.; Arthur, J. [Health and Safety Laboratory, Sheffield (United Kingdom)

    1997-12-31

    An electret-based passive dust sampler has been developed by the Health and Safety Laboratory, UK. The device consists of a small disc of electret (polymer holding a permanent electric charge) held between earthen plates, and it acts by attaching charged dust particles to itself. The device does not require a pump and its rate of sampling is independent of external air velocity, provided that the velocity exceeds a low limiting value. Experiments have been carried out in two coal mines. In each experiment two passive sampler were mounted alongside an MRE sampler at the statutory sampling point in the return roadway. Both passive samplers were mounted vertically but in one the plane of the electret was parallel to the air flow and in the other it was perpendicular. The result obtained from the first mine showed a good correlation between gravimetric estimates of dust concentration obtained with the passive samplers and respirable dust concentrations obtained with MRE. The correlation between the two sets of results at the second mine was not quite as good as those of the first, but was reasonable. In no instance was any significant difference observed between samples obtained from pairs of passive samples in different orientations. 8 refs., 5 figs., 2 tabs.

  7. Performance of prototype high-flow inhalable dust sampler in a livestock production facility.

    Science.gov (United States)

    Anthony, T Renée; Cai, Changjie; Mehaffy, John; Sleeth, Darrah; Volckens, John

    2017-05-01

    A high-flow inhalable sampler, designed for operational flow rates up to 10 L/min using computer simulations and examined in wind tunnel experiments, was evaluated in the field. This prototype sampler was deployed in collocation with an IOM (the benchmark standard sampler) in a swine farrowing building to examine the sampling performance for assessing concentrations of inhalable particulate mass and endotoxin. Paired samplers were deployed for 24 hr on 19 days over a 3-month period. On each sampling day, the paired samplers were deployed at three fixed locations and data were analyzed to identify agreement and to examine systematic biases between concentrations measured by these samplers. Thirty-six paired gravimetric samples were analyzed; insignificant, unsubstantial differences between concentrations were identified between the two samplers (p = 0.16; mean difference 0.03 mg/m 3 ). Forty-four paired samples were available for endotoxin analysis, and a significant (p = 0.001) difference in endotoxin concentration was identified: the prototype sampler, on average, had 120 EU/m 3 more endotoxin than did the IOM samples. Since the same gravimetric samples were analyzed for endotoxin content, the endotoxin difference is likely attributable to differences in endotoxin extraction. The prototype's disposable thin-film polycarbonate capsule was included with the filter in the 1-hr extraction procedure while the internal plastic cassette of the IOM required a rinse procedure that is susceptible to dust losses. Endotoxin concentrations measured with standard plastic IOM inserts that follow this rinsing procedure may underestimate the true endotoxin exposure concentrations. The maximum concentrations in the study (1.55 mg/m 3 gravimetric, 2328 EU/m 3 endotoxin) were lower than other agricultural or industrial environments. Future work should explore the performance of the prototype sampler in dustier environments, where concentrations approach particulates not otherwise

  8. Side-by-side determination of workers' exposure to wood dust with IOM and open-faced samplers.

    Science.gov (United States)

    Cavlović, Anka Ozana; Beljo Lučić, Ružica; Jug, Matija; Radmanović, Kristijan; Bešlić, Ivan

    2013-09-01

    Woodworkers' exposure to airborne particles is measured with different sampling techniques throughout the world. Due to a great number of exposure data obtained with different samplers, European countries have aimed over the last ten years to find a conversion factor for mass concentrations that would render these measurements comparable. Following the accepted EU standards and regulations, we replaced a 25 mm open-faced (OF) filter holder with an IOM head to determine woodworkers' exposure to inhalable dust and establish an IOM/OF sampler ratio that might serve as a reliable factor for converting the existing OF data to IOM dust mass concentration in the industrial environment. For this side-by-side sampling we used personal 25 mm OF (N=29) and IOM (N=29) sampling heads over eight working hours. The obtained IOM/OF ratios ranged between 0.7 and 2.3. However, mass concentrations obtained by IOM and OF samplers did not significantly differ. Our findings suggest that there is no need for conversion of the existing OF data for workers exposed to wood dust, provided that dust mass concentrations in the working environment range between 1 mg m-3 and 7 mg m-3. Future side-by-side measurements should also involve environments with low wood dust mass concentrations.

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

    Science.gov (United States)

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

    2014-05-01

    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 passive air sampler is a simple low-cost method to assess potential exposures near contaminated mining sites.

  10. Comparison of the CAS-POL and IOM samplers for determining the knockdown efficiencies of water sprays on float coal dust.

    Science.gov (United States)

    Seaman, Clara E; Shahan, Michael R; Beck, Timothy W; Mischler, Steven E

    2018-03-01

    Float coal dust, generated by mining operations, is distributed throughout mine airways by ventilating air designed to purge gases and respirable dust. Float coal dust poses an explosion hazard in the event of a methane ignition. Current regulation requires the application of inert rock dust in areas subjected to float coal dust in order to mitigate the hazard. An alternate method using water sprays, which have been effective in controlling respirable dust hazards, has been proposed as a way to control float coal dust generated on longwall faces. However, the knockdown efficiency of the proposed water sprays on float coal dust needs to be verified. This study used gravimetric isokinetic Institute of Occupational Medicine (IOM) samplers alongside a real-time aerosol monitor (Cloud Aerosol Spectrometer with polarization; CAS-POL) to study the effects of spray type, operating pressure, and spray orientation on knockdown efficiencies for seven different water sprays. Because the CAS-POL has not been used to study mining dust, the CAS-POL measurements were validated with respect to the IOM samplers. This study found that the CAS-POL was able to resolve the same trends measured by the IOM samplers, while providing additional knockdown information for specific particle size ranges and locations in the test area. In addition, the CAS-POL data was not prone to the same process errors, which may occur due to the handling of the IOM filter media, and was able to provide a faster analysis of the data after testing. This study also determined that pressure was the leading design criteria influencing spray knockdown efficiency, with spray type also having some effect and orientation having little to no effect. The results of this study will be used to design future full-scale float coal dust capture tests involving multiple sprays, which will be evaluated using the CAS-POL.

  11. COSMIC EVOLUTION OF DUST IN GALAXIES: METHODS AND PRELIMINARY RESULTS

    International Nuclear Information System (INIS)

    Bekki, Kenji

    2015-01-01

    We investigate the redshift (z) evolution of dust mass and abundance, their dependences on initial conditions of galaxy formation, and physical correlations between dust, gas, and stellar contents at different z based on our original chemodynamical simulations of galaxy formation with dust growth and destruction. In this preliminary investigation, we first determine the reasonable ranges of the most important two parameters for dust evolution, i.e., the timescales of dust growth and destruction, by comparing the observed and simulated dust mass and abundances and molecular hydrogen (H 2 ) content of the Galaxy. We then investigate the z-evolution of dust-to-gas ratios (D), H 2 gas fraction (f H 2 ), and gas-phase chemical abundances (e.g., A O = 12 + log (O/H)) in the simulated disk and dwarf galaxies. The principal results are as follows. Both D and f H 2 can rapidly increase during the early dissipative formation of galactic disks (z ∼ 2-3), and the z-evolution of these depends on initial mass densities, spin parameters, and masses of galaxies. The observed A O -D relation can be qualitatively reproduced, but the simulated dispersion of D at a given A O is smaller. The simulated galaxies with larger total dust masses show larger H 2 and stellar masses and higher f H 2 . Disk galaxies show negative radial gradients of D and the gradients are steeper for more massive galaxies. The observed evolution of dust masses and dust-to-stellar-mass ratios between z = 0 and 0.4 cannot be reproduced so well by the simulated disks. Very extended dusty gaseous halos can be formed during hierarchical buildup of disk galaxies. Dust-to-metal ratios (i.e., dust-depletion levels) are different within a single galaxy and between different galaxies at different z

  12. COSMIC EVOLUTION OF DUST IN GALAXIES: METHODS AND PRELIMINARY RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Bekki, Kenji [ICRAR, M468, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

    2015-02-01

    We investigate the redshift (z) evolution of dust mass and abundance, their dependences on initial conditions of galaxy formation, and physical correlations between dust, gas, and stellar contents at different z based on our original chemodynamical simulations of galaxy formation with dust growth and destruction. In this preliminary investigation, we first determine the reasonable ranges of the most important two parameters for dust evolution, i.e., the timescales of dust growth and destruction, by comparing the observed and simulated dust mass and abundances and molecular hydrogen (H{sub 2}) content of the Galaxy. We then investigate the z-evolution of dust-to-gas ratios (D), H{sub 2} gas fraction (f{sub H{sub 2}}), and gas-phase chemical abundances (e.g., A {sub O} = 12 + log (O/H)) in the simulated disk and dwarf galaxies. The principal results are as follows. Both D and f{sub H{sub 2}} can rapidly increase during the early dissipative formation of galactic disks (z ∼ 2-3), and the z-evolution of these depends on initial mass densities, spin parameters, and masses of galaxies. The observed A {sub O}-D relation can be qualitatively reproduced, but the simulated dispersion of D at a given A {sub O} is smaller. The simulated galaxies with larger total dust masses show larger H{sub 2} and stellar masses and higher f{sub H{sub 2}}. Disk galaxies show negative radial gradients of D and the gradients are steeper for more massive galaxies. The observed evolution of dust masses and dust-to-stellar-mass ratios between z = 0 and 0.4 cannot be reproduced so well by the simulated disks. Very extended dusty gaseous halos can be formed during hierarchical buildup of disk galaxies. Dust-to-metal ratios (i.e., dust-depletion levels) are different within a single galaxy and between different galaxies at different z.

  13. Exposure of bakery and pastry apprentices to airborne flour dust using PM2.5 and PM10 personal samplers

    Directory of Open Access Journals (Sweden)

    Paris Christophe

    2007-11-01

    Full Text Available Abstract Background This study describes exposure levels of bakery and pastry apprentices to flour dust, a known risk factor of occupational asthma. Methods Questionnaires on work activity were completed by 286 students. Among them, 34 performed a series of two personal exposure measurements using a PM2.5 and PM10 personal sampler during a complete work shift, one during a cold ("winter" period, and the other during a hot ("summer" period. Results Bakery apprentices experience greater average PM2.5 and PM10 exposures than pastry apprentices (p 10 values among bakers = 1.10 mg.m-3 [standard deviation: 0.83] than in summer (0.63 mg.m-3 [0.36]. While complying with current European occupational limit values, these exposures exceed the ACGIH recommendations set to prevent sensitization to flour dust (0.5 mg.m-3. Over half the facilities had no ventilation system. Conclusion Young bakery apprentices incur substantial exposure to known airways allergens, a situation that might elicit early induction of airways inflammation.

  14. Exposure of bakery and pastry apprentices to airborne flour dust using PM2.5 and PM10 personal samplers.

    Science.gov (United States)

    Mounier-Geyssant, Estelle; Barthélemy, Jean-François; Mouchot, Lory; Paris, Christophe; Zmirou-Navier, Denis

    2007-11-01

    This study describes exposure levels of bakery and pastry apprentices to flour dust, a known risk factor of occupational asthma. Questionnaires on work activity were completed by 286 students. Among them, 34 performed a series of two personal exposure measurements using a PM2.5 and PM10 personal sampler during a complete work shift, one during a cold ("winter") period, and the other during a hot ("summer") period. Bakery apprentices experience greater average PM2.5 and PM10 exposures than pastry apprentices (p < 0.006). Exposure values for both particulate fractions are greater in winter (average PM10 values among bakers = 1.10 mg.m-3 [standard deviation: 0.83]) than in summer (0.63 mg.m-3 [0.36]). While complying with current European occupational limit values, these exposures exceed the ACGIH recommendations set to prevent sensitization to flour dust (0.5 mg.m-3). Over half the facilities had no ventilation system. Young bakery apprentices incur substantial exposure to known airways allergens, a situation that might elicit early induction of airways inflammation.

  15. Elementary analysis of airborne dust (preliminary findings of the AFR Coordinated Airborne Dust Programme (LVPr))

    International Nuclear Information System (INIS)

    1983-03-01

    In March 1981 the systematic measuring of 15 elements of airborne dust was started in the Coordinated Airborne Dust Program (LVPr) by the Association for the Promotion of Radionuclide Technology (AFR). The sampling was done under comparable conditions at five selected places within the Federal Republic of Germany by using especially developed large-filter High Volume Samplers. The aim of this research is to establish the foundation for further investigations on the effects of the current given element concentrations on human life. When the results of the first half-year (summer period) were in hand, these element concentrations, which had been analysed using different methods, were presented to a group of experts, also with the experience gained with the analytical methods, in order to critically assess procedure and philosophy of this study. This evaluation was done on the occasion of a colloquium on Jun 29th, 1982 at the Karlsruhe Nuclear Research Centre. The presented AFR-Report contains the papers and the discussions of this meeting as well as the average element data with respect to the sampling time between 15th and 40th week of the year 1981. The discussion contributions presented here correspond to the essential statements that have been given and recorded. A total classification of all data relating to the whole sampling time of the LVPr will be given in AFR-Report No. 007. (orig.) [de

  16. Household vacuum cleaners vs. the high-volume surface sampler for collection of carpet dust samples in epidemiologic studies of children

    Directory of Open Access Journals (Sweden)

    Buffler Patricia A

    2008-02-01

    Full Text Available Abstract Background Levels of pesticides and other compounds in carpet dust can be useful indicators of exposure in epidemiologic studies, particularly for young children who are in frequent contact with carpets. The high-volume surface sampler (HVS3 is often used to collect dust samples in the room in which the child had spent the most time. This method can be expensive and cumbersome, and it has been suggested that an easier method would be to remove dust that had already been collected with the household vacuum cleaner. However, the household vacuum integrates exposures over multiple rooms, some of which are not relevant to the child's exposure, and differences in vacuuming equipment and practices could affect the chemical concentration data. Here, we compare levels of pesticides and other compounds in dust from household vacuums to that collected using the HVS3. Methods Both methods were used in 45 homes in California. HVS3 samples were collected in one room, while the household vacuum had typically been used throughout the home. The samples were analyzed for 64 organic compounds, including pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls (PCBs, using GC/MS in multiple ion monitoring mode; and for nine metals using conventional microwave-assisted acid digestion combined with ICP/MS. Results The methods agreed in detecting the presence of the compounds 77% to 100% of the time (median 95%. For compounds with less than 100% agreement, neither method was consistently more sensitive than the other. Median concentrations were similar for most analytes, and Spearman correlation coefficients were 0.60 or higher except for allethrin (0.15 and malathion (0.24, which were detected infrequently, and benzo(kfluoranthene (0.55, benzo(apyrene (0.55, PCB 105 (0.54, PCB 118 (0.54, and PCB 138 (0.58. Assuming that the HVS3 method is the "gold standard," the extent to which the household vacuum cleaner method yields relative risk

  17. Sampler bias -- Phase 1

    International Nuclear Information System (INIS)

    Blanchard, R.J.

    1995-01-01

    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

  18. Preliminary analysis of hydrogen risk caused by dust in ITER

    International Nuclear Information System (INIS)

    Cheng Kun; Tong Lili; Cao Xuewu

    2012-01-01

    A lot of dust will be generated during ITER operation,and hydrogen will be produced by the interaction of hot dust with water in the case of coolant ingress accident. The accumulated hydrogen will bring risk of combustion and explosion,which will damage the device. CFD method has been used to analyze the produced hydrogen in 'wet bypass' scenario, and come to the results that hydrogen will burn and explode at the beginning of the accident, different hydrogen risk will be brought by different coolant leakage, and hydrogen risk will be inert if the leakage is massive.Injecting CO 2 to inert the vacuum vessel has also been discussed, the risk of hydrogen will be suppressed by injecting CO 2 with a large rate at the beginning of accident. (authors)

  19. High-volume samplers for the assessment of respirable silica content in metal mine dust via direct-on-filter analysis

    CSIR Research Space (South Africa)

    Cauda, EG

    2014-08-01

    Full Text Available -site silica quantification in the samples would allow the identification of high-risk tasks and appropriate dedicated control technologies. With the objective to find more timely silica monitoring solutions, the performance of five different samplers...

  20. The effects of electric forces on dust lifting: Preliminary studies with a numerical model

    International Nuclear Information System (INIS)

    Kok, J F; Renno, N O

    2008-01-01

    Atmospheric dust aerosols affect the Earth's climate by scattering and absorbing radiation and by modifying cloud properties. Recent experiments have indicated that electric fields produced in dusty phenomena such as dust storms and dust devils could enhance the emission of dust aerosols. However, the generation of electric fields in dusty phenomena is poorly understood. To address this problem, we present results from the first physically-based numerical model of electric fields in dust lifting. Our model calculates the motion and collisions of air-borne particles, as well as the charge transfer during these collisions. This allows us to simulate the formation of electric fields as a function of physical parameters, such as wind stress and soil properties. Preliminary model results show that electric fields can indeed enhance the lifting of soil particles. Moreover, they suggest that strong electric fields could trigger a positive feedback because increases in the concentration of charged particles strengthen the original electric field, which in turn lifts additional surface particles. We plan to further test and calibrate our model with experimental data.

  1. Preliminary Research on Granulation Process of Dust Waste from Reclamation Process of Moulding Sands with Furan Resin

    Directory of Open Access Journals (Sweden)

    J. Kamińska

    2012-09-01

    Full Text Available The results of investigations of the granulation process of foundry dusts generated in the dry mechanical reclamation process of usedsands, where furan resins were binders are presented in the paper. Investigations concerned producing of granules of the determineddimensions and strength parameters.Granules were formed from the dusts mixture consisting in 50 mass% of dusts obtained after the reclamation of the furane sands and in50 mass % of dusts from sands with bentonite. Dusts from the bentonite sands with water were used as a binder allowing the granulation of after reclamation dusts from the furane sands.The following parameters of the ready final product were determined: moisture content (W, shatter test of granules (Wz performeddirectly after the granulation process and after 1, 3, 5, 10 days and nights of seasoning, water-resistance of granules after 24 hours of being immersed in water, surface porosity ep and volumetric porosity ev. In addition the shatter test and water-resistance of granulate dried at a temperature of 105oC were determined.Investigations were performed at the bowl angle of inclination 45o, for three rotational speeds of the bowl being: 10, 15, 20 rpm.For the speed of 10 rpm the granulation tests of dusts mixture after the preliminary mixing in the roller mixer and with the addition ofwater-glass in the amount of 2% in relation to the amount of dust were carried out.The obtained results indicate that the granulator allows to obtain granules from dusts originated from the reclamations of mouldingsands with the furane resin with an addition of dusts from the bentonite sands processing plants.

  2. Preliminary experiment design of graphite dust emission measurement under accident conditions for HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Wei, E-mail: pengwei@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Chen, Tao; Sun, Qi; Wang, Jie [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Yu, Suyuan, E-mail: suyuan@tsinghua.edu.cn [Center for Combustion Energy, The Key Laboratory for Thermal Science and Power Engineering, Ministry of Education, Tsinghua University, Beijing 100084 (China)

    2017-05-15

    Highlights: • A theoretical analysis is used to predict the total graphite dust release for an AVR LOCA. • Similarity criteria must be satisfied between the experiment and the actual HTGR system. • Model experiments should be conducted to predict the graphite dust resuspension rate. - Abstract: The graphite dust movement behavior is significant for the safety analyses of high-temperature gas cooled reactor (HTGR). The graphite dust release for accident conditions is an important source term for HTGR safety analyses. Depressurization release tests are not practical in HTGR because of a radioactivity release to the environment. Thus, a theoretical analysis and similarity principles were used to design a group of modeling experiments. Modeling experiments for fan start-up and depressurization process and actual experiments of helium circulator start-up in an HTGR were used to predict the rate of graphite dust resuspension and the graphite dust concentration, which can be used to predict the graphite dust release during accidents. The modeling experiments are easy to realize and the helium circulator start-up test does not harm the reactor system or the environment, so this experiment program is easily achieved. The revised Rock’n’Roll model was then used to calculate the AVR reactor release. The calculation results indicate that the total graphite dust releases during a LOCA will be about 0.65 g in AVR.

  3. Preliminary Assessment of Health Risks of Potentially Toxic Elements in Settled Dust over Beijing Urban Area

    Directory of Open Access Journals (Sweden)

    Dejun Wan

    2016-05-01

    Full Text Available To examine levels, health risks, sources, and spatial distributions of potentially toxic elements in settled dust over Beijing urban area, 62 samples were collected mostly from residential building outdoor surfaces, and their <63 μm fractions were measured for 12 potentially toxic elements. The results show that V, Cr, Mn, Co, Ni, and Ba in dust are from predominantly natural sources, whereas Cu, Zn, As, Cd, Sb, and Pb mostly originate from anthropogenic sources. Exposure to these elements in dust has significant non-cancer risks to children but insignificant to adults. Cancer risks of Cr, Co, Ni, As, and Cd via inhalation and dermal contact are below the threshold of 10−6–10−4 but As via dust ingestion shows a tolerable risk. The non-cancer risks to children are contributed mainly (75% by As, Pb, and Sb, and dominantly (92% via dust ingestion, with relatively higher risks mainly occurring in the eastern and northeastern Beijing urban areas. Although Cd, Zn, and Cu in dust are heavily affected by anthropogenic sources, their health risks are insignificant. Source appointments suggest that coal burning emissions, the dominant source of As, are likely the largest contributors to the health risk, and traffic-related and industrial emissions are also important because they contribute most of the Pb and Sb in dust.

  4. Preliminary results on air pollution inside an iron metallurgical plant, using rotating streaker sampler and energy dispersive X-ray microfluorescence

    International Nuclear Information System (INIS)

    Nascimento Filho, V.F.; Silva, R.M.C.; Perez, C.A.

    2005-01-01

    Our aim was to study the chemical concentration of some metals in suspended particulate matter inside an-iron metallurgical plant. Using a rotating streaker air-particulate sampler with 8 and 0.45 microns pore diameter filter, it was possible to collect coarse and fine particulates during a week, with one hour step. After this, each strip of the filter was analyzed by energy dispersive x-ray microfluorescence (μ-EDXRF), using in the excitation a collimated x-ray line beam from a Mo target tube (30 kV, 20 mA, Zr filter) with a quartz capillary (120 mm long, 10 mm entrance diameter and 20 microns inner diameter at exit). The detection was carried out using a Si(Li) semiconductor detector coupled to a multichannel analyzer, and the X-ray spectra were fitted with the AXIL software. The profiles of several elements are shown and the results are discussed.

  5. Preliminary study on immobilization of buffing dust by solidification method in ceramic brick

    Science.gov (United States)

    Yuliansyah, Ahmad Tawfiequrrahman; Prasetya, Agus; Putra, Arif Eka; Satriawan, Humam Budi

    2017-11-01

    Leather-based industries generate a substantial amount of hazardous solid and liquid wastes in their process. One of the solid wastes is buffing dust, which is fine particulates containing fat, tanning, dyes and chromium. From 1 ton of leather processed, approximately 2-6 kg of buffing dust is generated. Chromium in the buffing dust is carcinogenic, so a proper handling is highly required. Solidification is a method commonly used to immobilize toxic material. Hence, the material is trapped in a matrix made of binding agents to minimize its mobility. However, a very small amount of the materials is sometimes released to the environment during storage. This study investigates leaching process of chromium from immobilized buffing dust in ceramic brick. Buffing dust, which contains chromium, is solidified by mixing it with clay at certain compositions and fired in a muffle furnace to produce a ceramic brick. Performance of the solidification process is evaluated by measuring the leaching of chromium in the leaching test. The results show that the solidification has significantly reduced the potential release of chromium to the environment. Higher of the firing temperature, less chromium is leached from ceramic brick. The chromium concentration of leachate water from 800°C brick is 0.376 ppm, while those from 850 and 900°C brick are 0.212 and 0.179 ppm respectively.

  6. Preliminary assessment for dust contamination of ITER In-Vessel Transporter

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Makiko, E-mail: saito.makiko@jaea.go.jp [Japan Atomic Energy Agency, Fusion Research and Development Directorate, Naka, Ibaraki-ken 311-0193 (Japan); Ueno, Kenichi; Maruyama, Takahito; Murakami, Shin; Takeda, Nobukazu; Kakudate, Satoshi [Japan Atomic Energy Agency, Fusion Research and Development Directorate, Naka, Ibaraki-ken 311-0193 (Japan); Nakahira, Masataka; Tesini, Alessandro [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France)

    2014-10-15

    Highlights: •To assess the exposure to the maintenance workers, we calculated the effective dose rate. •To reduce the effective dose rate, the IVT was decontaminated and underwent a design change. •The effective dose rate at each maintenance point was also calculated. -- Abstract: After plasma operations of ITER, radioactive dust will have accumulated in the vacuum vessel (VV). The In-Vessel Transporter (IVT) will be introduced into the VV to remove the shield blanket modules for maintenance or replacement and later reinstall them. The IVT itself also needs to undergo regular maintenance in the Hot Cell Facility (HCF). It is assumed that maintenance workers will be exposed to radioactive dust that has adhered to the surfaces of the IVT. In this study, the areas of the IVT that may be contaminated by dust are evaluated to assess the level of exposure to workers during maintenance work in the HCF. Decontamination processes for the IVT, such as a combination of vacuuming and brushing, were investigated and the dose rate after these processes was evaluated. Even though dust was removed from surfaces where decontamination was possible, the dose rate was very high at some assessment points. To decrease the dose rate in accordance with ALARA policy, a decontamination plan and a maintenance plan, which includes the removal of dust, a radiation shield system, and a reduction in working time are proposed.

  7. Indoor Sampler Siting

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Michael D.; Lorenzetti, David M.

    2009-03-01

    Contaminant releases in or near a building can lead to significant human exposures unless prompt response is taken. U.S. Federal and local agencies are implementing programs to place air-monitoring samplers in buildings to quickly detect biological agents. We describe a probabilistic algorithm for siting samplers in order to detect accidental or intentional releases of biological material. The algorithm maximizes the probability of detecting a release from among a suite of realistic scenarios. The scenarios may differ in any unknown, for example the release size or location, weather, mode of building operation, etc. The algorithm also can optimize sampler placement in the face of modeling uncertainties, for example the airflow leakage characteristics of the building, and the detection capabilities of the samplers. In an illustrative example, we apply the algorithm to a hypothetical 24-room commercial building, finding optimal networks for a variety of assumed sampler types and performance characteristics. We also discuss extensions of this work for detecting ambient pollutants in buildings, and for understanding building-wide airflow, pollutant dispersion, and exposures.

  8. Sampling Efficiency and Performance of Selected Thoracic Aerosol Samplers.

    Science.gov (United States)

    Görner, Peter; Simon, Xavier; Boivin, Alexis; Bau, Sébastien

    2017-08-01

    Measurement of worker exposure to a thoracic health-related aerosol fraction is necessary in a number of occupational situations. This is the case of workplaces with atmospheres polluted by fibrous particles, such as cotton dust or asbestos, and by particles inducing irritation or bronchoconstriction such as acid mists or flour dust. Three personal and two static thoracic aerosol samplers were tested under laboratory conditions. Sampling efficiency with respect to particle aerodynamic diameter was measured in a horizontal low wind tunnel and in a vertical calm air chamber. Sampling performance was evaluated against conventional thoracic penetration. Three of the tested samplers performed well, when sampling the thoracic aerosol at nominal flow rate and two others performed well at optimized flow rate. The limit of flow rate optimization was found when using cyclone samplers. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  9. Optimising a fall out dust monitoring sampling programme at a ...

    African Journals Online (AJOL)

    GREG

    Key words: Fall out dust monitoring, cement plant, optimising, air pollution sampling, fall out dust sampler locations. .... applied for those areas where controls are in place. Sampling ..... mass balance in the total cement manufacturing process.

  10. Indigenous high volume air sampler

    International Nuclear Information System (INIS)

    Kotrappa, P.; Setty, N.P.N.; Raghunath, B.; Sivasubrahmanyam, P.S.

    1978-01-01

    A high volume air sampler for use in assessing concentrations of low levels of air borne particulates has been fabricated. The sampler will be of use in radioactive installations, conventional industries and environmental pollution analysis. It is comparable in performance with the imported Staplex air samplers. A turbine and motor system similar to the one found in conventional vacuum cleaners is used in its design. The sampler units can be produced in large numbers. (M.G.B.)

  11. Particle-capturing performance of South African non-corrosive samplers

    CSIR Research Space (South Africa)

    Pretorius, CJ

    2011-10-01

    Full Text Available analysis (PSA) could be carried out. The duration of the sampling was established at ? 30 seconds, so the mass of dust collected per sample ranged from 1 to 2 mg. The flow rates for each sampler were specified by the suppliers. For the X... chain to eliminate pulsation in the air flow. The pressure loss due to air flow resistance was measured with a digital micro manometer for each sampler with 2.2 L/min passing through the sampler (2.5 L/min for the aluminium samplers). PSA...

  12. Air sampler performance at Ford's farm range

    International Nuclear Information System (INIS)

    Glissmeyer, J.A.; Johnston, J.W.

    1984-07-01

    An air-sampling system for a large-caliber depleted uranium (DU) penetrator firing range was tested. The objectives of the test were: to determine the bias between the monitoring readings and DU concentrations; and to determine if the target bay real-time monitor (RTM) tracks the decaying dust concentration. The test procedure was to operate total and respirable airborne particle samplers adjacent to the target bay monitors. A series of air samples was also taken after the test firings adjacent to the target bay RTM. Exhaust particle samples were analyzed for gross alpha, gross beta and uranium content. The target bay RTM correlated well (0.977) with the sequential samples. Average concentration from the RTM did not correlate with either the long-term total or respirable sampler DU concentrations. The monitor used to confirm a low dust concentration when the door is open correlated well (0.810) with the RTM; the other bay monitor did not. In the ventilation discharge, the long-term average monitor readings did not correlate with DU concentrations, probably due to levels near lower detection limits. Smearable surface-contamination samples showed highest contamination on the equipment, gravel floor and exhaust intake. The location air-intake contamination increased over the first 3 rounds. Contamination was reduced by a low-pressure water spray washdown to about the same concentration as often the second round, then remained at about twice the level. 2 references, 18 figures, 16 tables. (MF)

  13. Isokinetic sampler; Amostrador isocinetico

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luis Cesar C. de; Santos, Antonio Carlos dos [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil); Barrio, Lara B.A. del [AZ Armaturen do Brasil Ltda., Itatiba, SP (Brazil); Silva, Claudio B. da C. e; Silva, Ricardo R. da [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2005-07-01

    The Center of Research Leopoldo A. Miguez de Melo - CENPES - in association with AZ Armaturen Company do Brasil and TRANSPETRO developed and tested an Isokinetic sampler. This work presents the sampling principles and the results and performance of the tests realized in the 'Sitio de Testes de Atalaia' and in one of the terminals of bunker transfer of TRANSPETRO - 'Terminal Aquaviario da Baia de Guanabara'. In the 'Sitio de Testes' the products used were oil and water with BSW from 5% to 97% and in the terminal were tested samplings of bunker with ranges viscosities between (MF 180 to 380). (author)

  14. Waveform Sampler CAMAC Module

    International Nuclear Information System (INIS)

    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 μs conversion time and stored in an on-board memory accessible through CAMAC

  15. Sampling of high amounts of bioaerosols using a high-volume electrostatic field sampler

    DEFF Research Database (Denmark)

    Madsen, A. M.; Sharma, Anoop Kumar

    2008-01-01

    For studies of the biological effects of bioaerosols, large samples are necessary. To be able to sample enough material and to cover the variations in aerosol content during and between working days, a long sampling time is necessary. Recently, a high-volume transportable electrostatic field...... and 315 mg dust (net recovery of the lyophilized dust) was sampled during a period of 7 days, respectively. The sampling rates of the electrostatic field samplers were between 1.34 and 1.96 mg dust per hour, the value for the Gravikon was between 0.083 and 0.108 mg dust per hour and the values for the GSP...... samplers were between 0.0031 and 0.032 mg dust per hour. The standard deviations of replica samplings and the following microbial analysis using the electrostatic field sampler and GSP samplers were at the same levels. The exposure to dust in the straw storage was 7.7 mg m(-3) when measured...

  16. Introduction to SamplerCompare

    Directory of Open Access Journals (Sweden)

    Madeleine B. Thompson

    2011-08-01

    Full Text Available SamplerCompare is an R package for comparing the performance of Markov chain Monte Carlo (MCMC samplers. It samples from a collection of distributions with a collection of MCMC methods over a range of tuning parameters. Then, using log density evaluations per uncorrelated observation as a figure of merit, it generates a grid of plots showing the results of the simulation. It comes with a collection of predefined distributions and samplers and provides R and C interfaces for defining additional ones. It also provides the means to import simulation data generated by external systems. This document provides background on the package and demonstrates the basics of running simulations, visualizing results, and defining distributions and samplers in R.

  17. Vertical transport of desert particulates by dust devils and clear thermals

    International Nuclear Information System (INIS)

    Sinclair, P.C.

    1974-01-01

    While the vertical and horizontal transport of natural surface material by dust devils is not in itself a critical environmental problem, the transport and downwind fallout of toxic or hazardous materials from dust devil activity may be a contributing factor in the development of future ecological-biological problems. Direct quantitative measurements of the dust particle size distribution near and within the visible dust devil vortex and analyses of the upper level clear thermal plume have been made to provide estimates of the vertical and horizontal transport of long half-life radioactive substances such as plutonium. Preliminary measurements and calculations of dust concentrations within dust devils indicate that over 7 x 10 3 tons of desert dust and sand may be transported downwind from an area 285 km 2 during an average dust devil season (May to August). Near the ground these dust concentrations contain particles in the size range from approximately 1 μm to 250 μm diameter. Since the vertical velocity distribution greatly exceeds the particle(s) fall velocities, the detrainment of particles within the vortex is controlled primarily by the spatial distribution of the radial (v/sub r/) and tangential (v/sub theta/) velocity fields. Above the visible dust devil vortex, a clear thermal plume may extend upward to 15,000 to 18,000 ft MSL. A new airborne sampling and air data system has been developed to provide direct measurements of the dust concentration and air motion near and within the upper thermal plume. The air sampler has been designed to operate isokinetically over a considerable portion of the low-speed flight regime of a light aircraft. A strapped down, gyro-reference platform and a boom-vane system is used to determine the vertical air motions as well as the temperature and turbulence structure within the thermal plume. (U.S.)

  18. Triadic split-merge sampler

    Science.gov (United States)

    van Rossum, Anne C.; Lin, Hai Xiang; Dubbeldam, Johan; van der Herik, H. Jaap

    2018-04-01

    In machine vision typical heuristic methods to extract parameterized objects out of raw data points are the Hough transform and RANSAC. Bayesian models carry the promise to optimally extract such parameterized objects given a correct definition of the model and the type of noise at hand. A category of solvers for Bayesian models are Markov chain Monte Carlo methods. Naive implementations of MCMC methods suffer from slow convergence in machine vision due to the complexity of the parameter space. Towards this blocked Gibbs and split-merge samplers have been developed that assign multiple data points to clusters at once. In this paper we introduce a new split-merge sampler, the triadic split-merge sampler, that perform steps between two and three randomly chosen clusters. This has two advantages. First, it reduces the asymmetry between the split and merge steps. Second, it is able to propose a new cluster that is composed out of data points from two different clusters. Both advantages speed up convergence which we demonstrate on a line extraction problem. We show that the triadic split-merge sampler outperforms the conventional split-merge sampler. Although this new MCMC sampler is demonstrated in this machine vision context, its application extend to the very general domain of statistical inference.

  19. Determining the spatial variability of personal sampler inlet locations.

    Science.gov (United States)

    Vinson, Robert; Volkwein, Jon; McWilliams, Linda

    2007-09-01

    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 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.

  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

    Science.gov (United States)

    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. The suitability of the IOM foam sampler for bioaerosol sampling in Occupational Environments.

    Science.gov (United States)

    Haatainen, Susanna; Laitinen, Juha; Linnainmaa, Markku; Reponen, Tiina; Kalliokoski, Pentti

    2010-01-01

    Concurrent samples were collected with Andersen and IOM foam samplers to determine whether if the IOM foam sampler can be applied to collect culturable microorganisms. Two different kinds of aerosols were studied: peat dust in a power plant and mist from coolant fluid aerosolized during grinding of blades and rollers in a paper mill. In the power plant, the concentrations of fungi were 2-3 times higher in the IOM samples than in the Andersen samples. However, more fungal genera were identified in the latter case. The methods yielded similar concentrations of bacteria and actinobacteria in the power plant. On the other hand, the performance of the IOM foam sampler was very poor in the paper mill, where stress-sensitive gram-negative bacteria dominated; low concentration of bacteria was detected in only one IOM sample even though the concentration of bacteria often exceeded even the upper detection limit in the Andersen impactor samples. It could be concluded that the IOM foam sampler performs quite well for collecting inhalable fungi and actinobacteria. However, the Andersen sampler provides better information on fungal genera and concentrations of gram-negative bacteria. Personal sampling with the IOM foam sampler provided an important benefit in the power plant, where the concentration ratio of personal to stationary samples was much higher for bacteria than for inhalable or respirable dust.

  2. Preliminary Tests of Gloss-Reduction and Coloring Agents for Camouflage of Polyvinyl Acetate Dust-Control Film

    Science.gov (United States)

    1976-02-01

    extenders Kaolin powder Calcium carbonate dust Paint flatteners Celite h99 Nytal 1+00 Dry pigments Chalk dust (various colors) Liquid...a dispersant or wetting agent for satisfactory mixing. Vor this purpose, one of two agents was used: (a) a commercial 10 per- cent determent...pockets of unmixed powder, and in some cases the powder settled to the bottom of the mold. The dispersants that were tried did not effectively disperse

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

    Science.gov (United States)

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

    2018-03-12

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

  4. The effect of size-selective samplers (cyclones) on XRD response

    CSIR Research Space (South Africa)

    Pretorius, CJ

    2011-07-01

    Full Text Available The study evaluated five size-selective samplers used in the South African mining industry to determine how their performance affects the X-ray powder diffraction (XRD) response when respirable dust samples are analysed for quartz using direct...

  5. Design of dry sand soil stratified sampler

    Science.gov (United States)

    Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

    2018-04-01

    This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

  6. Stardust Interstellar Preliminary Examination X: Impact Speeds and Directions of Interstellar Grains on the Stardust Dust Collector

    Science.gov (United States)

    Sterken, Veerle J.; Westphal, Andrew J.; Altobelli, Nicolas; Grun, Eberhard; Hillier, Jon K.; Postberg, Frank; Allen, Carlton; Stroud, Rhonda M.; Sandford, S. A.; Zolensky, Michael E.

    2014-01-01

    On the basis of an interstellar dust model compatible with Ulysses and Galileo observations, we calculate and predict the trajectories of interstellar dust (ISD) in the solar system and the distribution of the impact speeds, directions, and flux of ISD particles on the Stardust Interstellar Dust Collector during the two collection periods of the mission. We find that the expected impact velocities are generally low (less than 10 km per second) for particles with the ratio of the solar radiation pressure force to the solar gravitational force beta greater than 1, and that some of the particles will impact on the cometary side of the collector. If we assume astronomical silicates for particle material and a density of 2 grams per cubic centimeter, and use the Ulysses measurements and the ISD trajectory simulations, we conclude that the total number of (detectable) captured ISD particles may be on the order of 50. In companion papers in this volume, we report the discovery of three interstellar dust candidates in the Stardust aerogel tiles. The impact directions and speeds of these candidates are consistent with those calculated from our ISD propagation model, within the uncertainties of the model and of the observations.

  7. Preliminary Research on Granulation Process of Dust Waste from Reclamation Process of Moulding Sands with Furan Resin

    Directory of Open Access Journals (Sweden)

    Kamińska J.

    2012-09-01

    Full Text Available The results of investigations of the granulation process of foundry dusts generated in the dry mechanical reclamation process of used sands, where furan resins were binders are presented in the paper. Investigations concerned producing of granules of the determined dimensions and strength parameters.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. A Pilot Study: The UNC Passive Aerosol Sampler in a Working Environment.

    Science.gov (United States)

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

    2017-10-01

    Dust is generally sampled on a filter using air pumps, but passive sampling could be a cost-effective alternative. One promising passive sampler is the University of North Carolina passive aerosol sampler (UNC sampler). The aim of this study is to characterize and compare the UNC sampler's performance with PM10 and PM2.5 impactors in a working environment. Area sampling was carried out at different mining locations using UNC samplers in parallel with PM2.5 and PM10 impactors. Two different collection surfaces, polycarbonate (PC) and carbon tabs (CT), were employed for the UNC sampling. Sampling was carried out for 4-25 hours. The UNC samplers underestimated the concentrations compared to PM10 and PM2.5 impactor data. At the location with the highest aerosol concentration, the time-averaged mean of PC showed 24% and CT 35% of the impactor result for PM2.5. For PM10, it was 39% with PC and 58% with CT. Sample blank values differed between PC and CT. For PM2.5, PC blank values were ~7 times higher than those of CT, but only 1.8 times higher for PM10. The blank variations were larger for PC than for CT. Particle mass concentrations appear to be underestimated by the UNC sampler compared to impactors, more so for PM2.5 than for PM10. CT may be preferred as a collection surface because the blank values were lower and less variable than for PC. Future validations in the working environment should include respirable dust sampling. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  10. Comparison of coarse coal dust sampling techniques in a laboratory-simulated longwall section.

    Science.gov (United States)

    Patts, Justin R; Barone, Teresa L

    2017-05-01

    Airborne coal dust generated during mining can deposit and accumulate on mine surfaces, presenting a dust explosion hazard. When assessing dust hazard mitigation strategies for airborne dust reduction, sampling is done in high-velocity ventilation air, which is used to purge the mining face and gallery tunnel. In this environment, the sampler inlet velocity should be matched to the air stream velocity (isokinetic sampling) to prevent oversampling of coarse dust at low sampler-to-air velocity ratios. Low velocity ratios are often encountered when using low flow rate, personal sampling pumps commonly used in underground mines. In this study, with a goal of employing mine-ready equipment, a personal sampler was adapted for area sampling of coarse coal dust in high-velocity ventilation air. This was done by adapting an isokinetic nozzle to the inlet of an Institute of Occupational Medicine (Edinburgh, Scotland) sampling cassette (IOM). Collected dust masses were compared for the modified IOM isokinetic sampler (IOM-MOD), the IOM without the isokinetic nozzle, and a conventional dust sampling cassette without the cyclone on the inlet. All samplers were operated at a flow rate typical of personal sampling pumps: 2 L/min. To ensure differences between collected masses that could be attributed to sampler design and were not influenced by artifacts from dust concentration gradients, relatively uniform and repeatable dust concentrations were demonstrated in the sampling zone of the National Institute for Occupational Safety and Health experimental mine gallery. Consistent with isokinetic theory, greater differences between isokinetic and non-isokinetic sampled masses were found for larger dust volume-size distributions and higher ventilation air velocities. Since isokinetic sampling is conventionally used to determine total dust concentration, and isokinetic sampling made a difference in collected masses, the results suggest when sampling for coarse coal dust the IOM-MOD may

  11. A dusty road connecting Saturn and its rings - preliminary results from Cassini Cosmic Dust Analyser during the Grand Finale Mission

    Science.gov (United States)

    Hsu, S.; Burton, M. E.; Horanyi, M.; Kempf, S.; Khawaja, N.; Moragas-Klostermeyer, G.; Postberg, F.; Schirdenwahn, D.; Seiss, M.; Schmidt, J.; Spahn, F.; Srama, R.

    2017-12-01

    The Cosmic Dust Analyzer observations during the Cassini Grand Finale Orbits were designed for the in situ characterization of Saturn's ring composition and to study their interaction with the host planet. It is found that the gap between the inner most D ring and Saturn is almost free of larger, micron-sized dust grains but rich in nanodust particles (radius smaller than 100 nm) that only become detectable by CDA because of the high spacecraft speed of 30 km/s through this region. Regarding the grain composition, while the majority of CDA mass spectra recorded during this phase are too faint to be individually calibrated, two types of mass spectra have been identified - water ice and silicates. These two types of grains were detected at different locations with respect to the ring plane, indicating that there are compositional differences across the rings. As for the dynamics, the observations confirm the transport of charged nanodust from the main rings along magnetic field lines to the planet, as previously proposed. The agreement between the simulated density profile and the observation strongly suggests nanodust as a pathway of ring-planet interaction associated with both exogenous (e.g., impactor ejecta) and endogenous (ionospheric plasma charging) processes. CDA measurements do not indicate significant temporal variation during the the Grand Finale orbits. The measured flux corresponds to a mass transport of < 0.1 kg/sec from the main rings to Saturn in the form of nanodust, with most of the deposition occurring near the equator.

  12. Remote Sampler Demonstration Isolok Configuration Test

    International Nuclear Information System (INIS)

    Kelly, Steve E.

    2016-01-01

    The accuracy and precision of a new Isolok sampler configuration was evaluated using a recirculation flow loop. The evaluation was performed using two slurry simulants of Hanford high-level tank waste. Through testing, the capability of the Isolok sampler was evaluated. Sample concentrations were compared to reference samples that were simultaneously collected by a two-stage Vezin sampler. The capability of the Isolok sampler to collect samples that accurately reflect the contents in the test loop improved – biases between the Isolok and Vezin samples were greatly reduce for fast settling particles.

  13. Remote Sampler Demonstration Isolok Configuration Test

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Steve E. [Washington River Protection Solutions, LLC, Richland, WA (United States)

    2016-06-08

    The accuracy and precision of a new Isolok sampler configuration was evaluated using a recirculation flow loop. The evaluation was performed using two slurry simulants of Hanford high-level tank waste. Through testing, the capability of the Isolok sampler was evaluated. Sample concentrations were compared to reference samples that were simultaneously collected by a two-stage Vezin sampler. The capability of the Isolok sampler to collect samples that accurately reflect the contents in the test loop improved – biases between the Isolok and Vezin samples were greatly reduce for fast settling particles.

  14. SNOW COVER OF THE CENTRAL ANTARCTICA (VOSTOK STATION AS AN IDEAL NATURAL TABLET FOR COSMIC DUST COLLECTION: PRELIMINARY RESULTS ON THE IDENTIFICATION OF MICROMETEORITES OF CARBONACEOUS CHONDRITE TYPE

    Directory of Open Access Journals (Sweden)

    E. S. Bulat

    2012-01-01

    Full Text Available During the 2010/11 season nearby the Vostok station the 56th Russian Antarctic Expedition has collected surface snow in a big amount from a 3 m deep pit using 15 220 L vol. containers (about 70 kg snow each. Snow melting and processing by ultra-centrifugation was performed in a clean (class 10 000 and 100 laboratory. Total dust concentrations were not exceeded 37.4 mkg per liter with particle dispersal mode around 2.5 mkm. To analyze the elemental composition of fine dust particles aimed to reveal Antarctic micrometeorites (AMM two electron microscopy devices equipped with different micro-beams were implemented. As a preliminary result, three particles (of 107 analyzed featured by Mg content clearly dominated over Al along with Si and Fe as major elements (a feature of carbonaceous chondrites were observed. By this the Vostok AMM CS11 collection was established. The occurrence of given particles was averaged 2.8% – the factual value obtained for the first time for chondritic type AMM at Vostok which should be considered as the lowest estimate for all other families of AMM. Given the reference profile of total dust content in East Antarctic snow during Holocene (18 mkg/kg the MM deposition in Antarctica was quantified for the first time – 14 tons per day for carbonaceous chondrites for the Vostok AMM CS11 collection and up to 245 tons per day for all MM types for the Concordia AMM DC02 collection. The results obtained allowed to prove that snow cover (ice sheet in total of Central East Antarctica is the best spot (most clean of other natural locations and always below 0 ºC for collecting native MM deposited on the Earth during the last million years and could be useful in deciphering the origin and evolution of solid matter in our Solar System and its effects on Earth-bound biogeochemical and geophysical processes including the life origin. The farther analyses of the Vostok AMMs are in a progress.

  15. Dust emissions from unpaved roads on the Colorado Plateau

    Science.gov (United States)

    Duniway, M.; Flagg, C.; Belnap, J.

    2013-12-01

    On the Colorado Plateau, elevated levels of aeolian dust have become a major land management and policy concern due to its influence on climate, weather, terrestrial ecosystem dynamics, landscape development and fertility, melting of snow and ice, air quality, and human health. Most desert soil surfaces are stabilized by plants, rocks, and/or physical or biological soil crusts, but once disturbed, sediment production from these surfaces can increase dramatically. Road development and use is a common surface disturbing activity in the region. The extent and density of roads and road networks is rapidly increasing due to continued energy exploration, infrastructure development, and off-highway recreation activities. Though it is well known that unpaved roads produce dust, the relative contribution of dust from existing roads or the implications of future road development to regional dust loading is unknown. To address this need, we have initiated a multifaceted research effort to evaluating dust emissions from unpaved roads regionally. At 34 sites arranged across various road surfaces and soil textures in southeastern Utah, we are: 1) monitoring dust emissions, local wind conditions, and vehicle traffic and 2) evaluating fugitive dust potential using a portable wind tunnel and measuring road characteristics that affect dust production. We will then 3) develop a GIS-based model that integrates results from 1 & 2 to estimate potential dust contributions from current and future scenarios of regional road development. Passive, horizontal sediment traps were installed at three distances downwind from the road edge. One control trap was placed upwind of the samplers to account for local, non-road dust emissions. An electronic vehicle counter and anemometer were also installed at monitoring sites. Dust samples were collected every three months at fixed heights, 15 cm up to 100 cm above the soil surface, from March 2010 to the present. Threshold friction velocities (TFV

  16. Engineering gravimetric monitoring methods to cope with excessively high dust levels-2.

    CSIR Research Space (South Africa)

    Belle, BK

    1999-11-01

    Full Text Available -test and F-test), the mean dust concentration measured by pairs of cyclones is not significantly affected at 95 percent level of confidence. In other words, there is no difference between the measured mean dust concentration levels between various sampler... List of Figures . . . . . . . 8 List of Tables . . . .. . . 11 Glossary of Abbreviations and Symbols . . . . . 12 Acknowledgements . . . . . . . . 13 1 Introduction . . . . . . . 14 2 Background . . . . . . . 14 3 Test Samplers . . . . . . . 16...

  17. Comparison of personal air samplers and static air samplers

    International Nuclear Information System (INIS)

    Carter, M.W.; Lumsden, B.

    1979-01-01

    The authors demonstrate that radioactive air contamination levels calculated from PAS results will always be higher than air contamination levels calculated from SAS results, other conditions being equal. The most probable explanation seems to be in a relationship between the sampling velocity and the particle size of the dust sampled

  18. Dust collector

    Energy Technology Data Exchange (ETDEWEB)

    Sahourin, H.

    1988-03-22

    This invention relates to a dust collector or filter which may be used for large volume cleaning air for gases or for separating out industrial byproducts such as wood chips, sawdust, and shavings. It relies on filtration or separation using only a uniquely configured medium. A primary, but not exclusive, purpose of the invention is to enable very large throughput, capable of separating or filtering of gases containing up to three or more tons of byproduct with a minimum pressure-drop across the device. No preliminary cycloning, to remove major particulates is necessary. The collector generally comprises a continuous and integral filter medium which is suspended from a plurality of downwardly extending frames forming a series of separate elements having a triangular cross-section, each element being relatively wide at the top and narrow at the bottom to define, between adjacent elements, a divergent collecting space which is wide at the bottom. 11 figs.

  19. 7 CFR 61.30 - Examination of sampler.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Examination of sampler. 61.30 Section 61.30... Cottonseed Samplers § 61.30 Examination of sampler. Each applicant for a license as a sampler and each... examination or test to show his ability properly to perform the duties for which he is applying for a license...

  20. UWB Sampler for Wireless Communications and Radar

    National Research Council Canada - National Science Library

    Han, Jeongwoo; Nguyen, Cam

    2005-01-01

    An ultra wideband (UWB) sampler, realized using step recovery and Schottky diodes on coplanar waveguide, coplanar strips and slotlines, has been developed for UWB wireless communications and radar systems...

  1. A passive sampler for atmospheric ozone

    International Nuclear Information System (INIS)

    Grosjean, D.; Hisham, M.W.M.

    1992-01-01

    A simple, cost-effective passive sampler has been developed for the determination of atmospheric ozone. This passive sampler is based on a colorant which fades upon reaction with ozone, whose concentration can be determined by reflectance measurement of the color change. Direct, on-site measurements are possible, and no chemical analyses are needed. Sampler design and validation studies have been carried out and included quantitative determination of color change vs exposure time (1-8 days), color change vs. ozone concentration (30-350 ppb), and response to changes in sampler configuration that modify the passive sampling rate. With indigo carmine as the colorant, the detection limits are 30 ppb. day and 120 ppb. day using a plastic grid and Teflon filter, respectively, as diffusion barriers. Interferences from nitrogen dioxide, formaldehyde and peroxyacetyl nitrate are 15, 4 and 16%, respectively, thus resulting in a negligible bias when measuring ozone in ambient air

  2. Sampler collection gadget for epilithic diatoms.

    Science.gov (United States)

    Salomoni, S E; Torgan, L C; Rocha, O

    2007-11-01

    This work present a new gadget for sampling epilithic diatoms from both lentic and lotic enviroments. The sampler consists of a polystyrene cylinder, left to float on the surface of the water, to which stone substrates are attached. This epilithic diatom sampler (EDS) can be used to detect spatial and temporal richness and density variation in the study of the diatom community, as well as in water quality monitoring.

  3. Sampler collection gadget for epilithic diatoms

    Directory of Open Access Journals (Sweden)

    SE. Salomoni

    Full Text Available This work present a new gadget for sampling epilithic diatoms from both lentic and lotic enviroments. The sampler consists of a polystyrene cylinder, left to float on the surface of the water, to which stone substrates are attached. This epilithic diatom sampler (EDS can be used to detect spatial and temporal richness and density variation in the study of the diatom community, as well as in water quality monitoring.

  4. Statistical analysis of the DWPF prototypic sampler

    International Nuclear Information System (INIS)

    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)

  5. Wood Dust

    Science.gov (United States)

    Learn about wood dust, which can raise the risk of cancers of the paranasal sinuses and nasal cavity. High amounts of wood dust are produced in sawmills, and in the furniture-making, cabinet-making, and carpentry industries.

  6. Environmental HTO/HT sampler development

    International Nuclear Information System (INIS)

    Workman, W.J.G.; Brown, R.M.; Wood, M.J.

    1992-12-01

    Tests of retention by several drying agents of HTO from an air stream containing HT have been performed. Two batches of Molecular Sieve (MS) 4A retained up to 1.3% of HT passed through them in contrast to material tested in 1986, when retention was -4 . Retention of 10 -5 to 10 -6 was observed for DRIERITE (anhydrous calcium sulphate) and Silica Gel. DRIERITE is preferred over Silica Gel as a desiccant in an air sampler for environmental HTO/HT, because it is much easier to decontaminate for reuse. An improved air sampler has been designed, 2 units constructed and components procured for 3 more. The air sampler may be line or battery operated, accommodates up to four 120 g drier or oxidizer traps, and will pump up to 4 L/min for up to 24 hours on battery power. It is build into a rugged aluminum case and weighs approximately 11 kg overall, facilitating deployment in the field

  7. Coalescent genealogy samplers: windows into population history.

    Science.gov (United States)

    Kuhner, Mary K

    2009-02-01

    Coalescent genealogy samplers attempt to estimate past qualities of a population, such as its size, growth rate, patterns of gene flow or time of divergence from another population, based on samples of molecular data. Genealogy samplers are increasingly popular because of their potential to disentangle complex population histories. In the last decade they have been widely applied to systems ranging from humans to viruses. Findings include detection of unexpected reproductive inequality in fish, new estimates of historical whale abundance, exoneration of humans for the prehistoric decline of bison and inference of a selective sweep on the human Y chromosome. This review summarizes available genealogy-sampler software, including data requirements and limitations on the use of each program.

  8. Overflow type sodium sampler for FBTR circuits

    International Nuclear Information System (INIS)

    Muralidaran, P.; Ganesan, V.; Chandran, K.; Periaswami, G.

    1996-01-01

    Obtaining a representative sample is crucial for getting reliable results in sodium analysis. Sampling liquid sodium reliability is complicated since impurities segregate while cooling. Selective sorption of certain elements calls for use of different crucible materials for various sodium impurities. Sampling methods currently in use such as flow through sampling and dip sampling are not the proper methods as they can not take care of the above problems. An overflow type sampler where the entire sample contained in a crucible can be used for analysis thus obviating problems due to segregation has been developed for use in Fast Breeder Test Reactor (FBTR). This report describes the construction and operation of this sampler. (author)

  9. Operability test report for 211BA flow proportional sampler

    International Nuclear Information System (INIS)

    Weissenfels, R.D.

    1995-01-01

    This operability report will verify that the 211-BA flow proportional sampler functions as intended by design. The sampler was installed by Project W-007H and is part of BAT/AKART for the BCE liquid effluent stream

  10. Particle capturing performance of South African non corrosive samplers

    CSIR Research Space (South Africa)

    Pretorius, C

    2010-05-01

    Full Text Available eq ue nc y D50 D90 © CSIR 2007 www.csir.co.za Particle size distribution of sampled filters taken in three platinum mines PSA results according to mine 0 2 4 6 8 10 12 14 16 X-Samplers Y-Samplers X-Samplers Y...

  11. Retained Gas Sampler Calibration and Simulant Tests

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. A programmable air sampler with adsorption tubes

    International Nuclear Information System (INIS)

    Riesing, J.; Roetzer, H.; Hick, H.

    1997-01-01

    The Air Sampler AS3 was utilized for the European Tracer Experiment (ETEX) to measure the concentrations of the perfluorocarbon tracers. At thirty-two sampling points these devices were placed to collect the tracer substances in adsorption tubes for subsequent laboratory analysis in the Environment Institute of the JRC Ispra. The Air Sampler is also suitable for monitoring the environment, particularly of industrial emitters or landfills, by sampling of volatile substances. The Air Sampler AS3 is a portable, user-friendly instrument due to light weight, ruggedness and reliable operation. It is capable of fully automatic sampling of air and gas with 24 adsorption tubes and program-controlled gas flow. Collection times can be programmed freely between 1 sec and 8 days and waiting times between 1 sec and 30 days. Programming is possible via keyboard, memory card or serial interface. A protocol of sampling control data is stored on a memory card giving documentation of sampling conditions. On the memory card there is space for the storage of 10 sampling programs and 10 sets of sampling control data. Before the start of ETEX the AS3 was used in a measurement campaign to measure the background concentrations of the perfluorocarbon tracers in Austria. In the provinces of Upper Austria and Salzburg the Air Sampler is used by the departments for environmental protection for the monitoring of BTX-concentrations in air. (author)

  13. Quantum Gibbs Samplers: The Commuting Case

    Science.gov (United States)

    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.

  14. Retained Gas Sampler Calibration and Simulant Tests

    International Nuclear Information System (INIS)

    CRAWFORD, B.A.

    2000-01-01

    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

  15. Cometary Dust

    Science.gov (United States)

    Levasseur-Regourd, Anny-Chantal; Agarwal, Jessica; Cottin, Hervé; Engrand, Cécile; Flynn, George; Fulle, Marco; Gombosi, Tamas; Langevin, Yves; Lasue, Jérémie; Mannel, Thurid; Merouane, Sihane; Poch, Olivier; Thomas, Nicolas; Westphal, Andrew

    2018-04-01

    This review presents our understanding of cometary dust at the end of 2017. For decades, insight about the dust ejected by nuclei of comets had stemmed from remote observations from Earth or Earth's orbit, and from flybys, including the samples of dust returned to Earth for laboratory studies by the Stardust return capsule. The long-duration Rosetta mission has recently provided a huge and unique amount of data, obtained using numerous instruments, including innovative dust instruments, over a wide range of distances from the Sun and from the nucleus. The diverse approaches available to study dust in comets, together with the related theoretical and experimental studies, provide evidence of the composition and physical properties of dust particles, e.g., the presence of a large fraction of carbon in macromolecules, and of aggregates on a wide range of scales. The results have opened vivid discussions on the variety of dust-release processes and on the diversity of dust properties in comets, as well as on the formation of cometary dust, and on its presence in the near-Earth interplanetary medium. These discussions stress the significance of future explorations as a way to decipher the formation and evolution of our Solar System.

  16. Performance improvements on passive activated charcoal 222Rn samplers

    International Nuclear Information System (INIS)

    Wei Suxia

    1996-01-01

    Improvements have been made on passive activated charcoal 222 Rn samplers with sintered metal filters. Based on the samplers of good adaptability to temperature and humidity developed before, better charcoal was selected to further improve their performance in radon absorption ability and moisture-resistance. And charcoal quantity in samplers was strictly controlled. The integration time constant of the improved samplers was about 4.3 days. As the sampler was combined with gamma spectrometer to measure radon concentration, the calibration factor was 0.518 min -1 ·Bq -1 ·m 3 for samplers of 7 days exposure time, and the minimum detectable concentration 0.28 Bq·m -3 if counting time for both background and sample is 1000 minutes. The improved samplers are suited to accurately determine the indoor and outdoor average radon concentration under conditions of great variation in temperature and humidity

  17. THE MEASUREMENT AND DISTRIBUTION OF WOOD DUST

    Directory of Open Access Journals (Sweden)

    Andrea Rosario Proto

    2010-03-01

    Full Text Available In Italy, the woodworking industry presents many issues in terms of occupational health and safety. This study on exposure to wood dust could contribute to the realization of a prevention model in order to limit exposure to carcinogenic agents to the worker. The sampling methodology illustrated the analysis of dust emissions from the woodworking machinery in operation throughout the various processing cycles. The quantitative and qualitative assessment of exposure was performed using two different methodologies. The levels of wood dust were determined according to EN indications and sampling was conducted using IOM and Cyclon personal samplers. The qualitative research of wood dust was performed using an advanced laser air particle counter. This allowed the number of particles present to be counted in real time. The results obtained allowed for an accurate assessment of the quality of the dust emitted inside the workplace during the various processing phases. The study highlighted the distribution of air particles within the different size classes, the exact number of both thin and ultra-thin dusts, and confirmed the high concentration of thin dust particles which can be very harmful to humans.

  18. Development of a passive sampler for gaseous mercury

    Science.gov (United States)

    Gustin, M. S.; Lyman, S. N.; Kilner, P.; Prestbo, E.

    2011-10-01

    Here we describe work toward development of the components of a cost effective passive sampling system for gaseous Hg that could be broadly deployed by nontechnical staff. The passive sampling system included an external shield to reduce turbulence and exposure to precipitation and dust, a diffusive housing that directly protects the collection surface during deployment and handling, and a collection surface. A protocol for cleaning and deploying the sampler and an analytical method were developed. Our final design consisted of a polycarbonate external shield enclosing a custom diffusive housing made from expanded PTFE tubing. Two collection surfaces were investigated, gold sputter-coated quartz plates and silver wires. Research showed the former would require extensive quality control for use, while the latter had interferences with other atmosphere constituents. Although the gold surface exhibited the best performance over space and time, gradual passivation would limit reuse. For both surfaces lack of contamination during shipping, deployment and storage indicated that the handling protocols developed worked well with nontechnical staff. We suggest that the basis for this passive sampling system is sound, but further exploration and development of a reliable collection surface is needed.

  19. Heavy water leak detection using diffusion sampler

    International Nuclear Information System (INIS)

    Joshi, M.L.; Hussain, S.A.

    1990-01-01

    In the Pressurrised Heavy Water Reactors (PHWRs) detection of the sources of heavy water leaks is importent both for the purpose of radiation hazard control as well as for the reduction of escape/loss of heavy water which, is an expensive nuclear material. This paper describes an application of tritium diffusion sampler for heavy water leak detection. The diffusion sampler comprises an usual tritium counting glass vial with a special orifice. The counting vial has water vapour, deficient in HTO concentration. The HTO present outside diffuses in the vial through the orifice, gets exchanged with water of the wet filter paper kept at the bottom and the moisture in the vial atmosphere which has HTO concentration lower than that outside. This results in continuation of net movement of HTO in the vial. The exchanged tritium is counted in liquid scintillation spectrometer. The method has a sensitivity of 10000 dpm/DAC-h. (author). 2 figs., 2 ta bs

  20. CAM and stack air sampler design guide

    International Nuclear Information System (INIS)

    Phillips, T.D.

    1994-01-01

    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

  1. Sorbent Film-Coated Passive Samplers for Explosives Vapour Detection Part A: Materials Optimisation and Integration with Analytical Technologies.

    Science.gov (United States)

    McEneff, Gillian L; Murphy, Bronagh; Webb, Tony; Wood, Dan; Irlam, Rachel; Mills, Jim; Green, David; Barron, Leon P

    2018-04-11

    A new thin-film passive sampler is presented as a low resource dependent and discrete continuous monitoring solution for explosives-related vapours. Using 15 mid-high vapour pressure explosives-related compounds as probes, combinations of four thermally stable substrates and six film-based sorbents were evaluated. Meta-aramid and phenylene oxide-based materials showed the best recoveries from small voids (~70%). Analysis was performed using liquid chromatography-high resolution accurate mass spectrometry which also enabled tentative identification of new targets from the acquired data. Preliminary uptake kinetics experiments revealed plateau concentrations on the device were reached between 3-5 days. Compounds used in improvised explosive devices, such as triacetone triperoxide, were detected within 1 hour and were stably retained by the sampler for up to 7 days. Sampler performance was consistent for 22 months after manufacture. Lastly, its direct integration with currently in-service explosives screening equipment including ion mobility spectrometry and thermal desorption mass spectrometry is presented. Following exposure to several open environments and targeted interferences, sampler performance was subsequently assessed and potential interferences identified. High-security building and area monitoring for concealed explosives using such cost-effective and discrete passive samplers can add extra assurance to search routines while minimising any additional burden on personnel or everyday site operation.

  2. Allergies, asthma, and dust

    Science.gov (United States)

    Reactive airway disease - dust; Bronchial asthma - dust; Triggers - dust ... Things that make allergies or asthma worse are called triggers. Dust is a common trigger. When your asthma or allergies become worse due to dust, you are ...

  3. Environmental HTO/HT sampler development

    International Nuclear Information System (INIS)

    Workman, W.J.G.; Brown, R.M.; Wood, M.J.

    1994-01-01

    Tests of retention by several drying agents of HTO from an air stream containing HT have been performed. Two batches of Molecular Sieve (MS) 4A retained up to 1.3% of HT passed through them, in contrast to material tested in 1986, when retention was -4 . Retention of 10 -5 to 10 -6 was observed for DRIERITE (anhydrous calcium sulphate) and Silica Gel. DRIERITE is preferred over Silica Gel as a desiccant in an air sampler for environmental HTO/HT, because it is much easier to decontaminate for reuse. An improved air sampler has been designed, 2 units constructed and components procured for 3 more. The air sampler may be line or battery operated, accommodates up to four 120 g drier or oxidizer traps, and will pump up to 4 L/min for up to 24 hours on battery power. It is built into a rugged aluminum case and weighs approximately 11 kg overall, facilitating deployment in the field. (author). 5 refs., 2 tabs., 4 figs

  4. Half-liter supernatant sampler system engineering work plan

    International Nuclear Information System (INIS)

    Ritter, G.A.

    1995-01-01

    The Tank Waste Remediation System (TWRS) pretreatment facility project W-236B, known as the Initial Pretreatment Module (IPM), requires samples of supernatants and sludges from 200 Area tank farms for planned hot testing work in support of IPM design. The IPM project has proposed the development of several new sampler systems. These systems include a 0.5-l supernatant sampler, 3-l and 25-l supernatant and sludge samplers, and a 4,000-l sampler system. The 0.5-l sampler will support IPM sampling needs in the 1 to 3 l range starting in late fiscal year 1995. This sampler is intended to be used in conjunction with the existing 100 ml bottle-on-a-string. The 3-l and 25-l systems will be based on the Savannah River Site's sampler system and will support IPM sampling needs in the 3 to 100 liter range. Most of the hot testing required for design of the IPM must be accomplished in the next 3 years. This work plan defines the tasks associated with the development of a 0.5-l sampler system. This system will be referred to as the Half-Liter Supernatant Sampler System (HLSSS). Specifically, this work plan will define the scope of work, identify organizational responsibilities, identify major technical requirements, describe configuration control and verification requirements, and provide estimated costs and schedule. The sampler system will be fully operational, including trained staff and operating procedures, upon completion of this task

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

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  6. Functional design criteria for the retained gas sampler system

    International Nuclear Information System (INIS)

    Wootan, D.W.

    1995-01-01

    A Retained Gas Sampler System (RGSS) is being developed to capture and analyze waste samples from Hanford Flammable Gas Watch List Tanks to determine both the quantity and composition of gases retained in the waste. The RGSS consists of three main components: the Sampler, Extractor, and Extruder. This report describes the functional criteria for the design of the RGSS components. The RGSS Sampler is based on the WHC Universal Sampler design with modifications to eliminate gas leakage. The primary function of the Sampler is to capture a representative waste sample from a tank and transport the sample with minimal loss of gas content from the tank to the laboratory. The function of the Extruder is to transfer the waste sample from the Sampler to the Extractor. The function of the Extractor is to separate the gases from the liquids and solids, measure the relative volume of gas to determine the void fraction, and remove and analyze the gas constituents

  7. Characterization of the GENT PM10 sampler. Appendix 18

    International Nuclear Information System (INIS)

    Hopke, Philip K.; Xie Ying; Raunemaa, Taisto; Biegalski, Steven; Landsberger, Sheldon

    1995-01-01

    An integral part of the Co-ordinated Research Programme: Applied Research on Air Pollution using Nuclear-Related Analytical Techniques is the PM 10 sampler that was designed by Dr. W. Maenhaut of the University of Gent. Each participant was provided with such a sampler so that comparable samples will be obtained by each of the participating groups. Thus, in order to understand the characteristics of this sampler, we have undertaken several characterization studies in which we have examine the aerodynamic collection characteristics of the impactor inlet and the reproducibility of the sample mass collection. The sampler does provide a collection efficiency that follows the guidelines for a PM 10 sampler. Comparing one of the original samplers built at the University of Gent with a unit built from the same plans at Clarkson University showed good reproducibility in mass collection. (author)

  8. Environmental monitoring of tritium in air with passive diffusion samplers

    International Nuclear Information System (INIS)

    Wood, M.J.; Workman, W.J.G.

    1992-01-01

    This paper reports on a field trail in which outdoor air was sampled with an active reference sampler and several passive HTO-in-air samplers simultaneously carried out at Chalk River Laboratories. Both passive and active samplers were changed on an approximately monthly schedule from 1990 September 2 to 1991 April 18. Average temperatures for the sampling intervals ranged from -8.06 degrees C to +15.5 degrees C and HTO-in-air concentrations measured by the active sampler were typically 10 Bq/m 3 . A total of 1290 passive HTO-in-air sampler measurements were made during the seven sampling intervals. The passive samplers used for the field trial were prepared with either tritium-free water or a solution of 50% tritium-free water and 50% ethylene glycol. As expected, the samplers prepared with the water-glycol solution performed more consistently than the samplers prepared with water only. Good agreement between passive and active sampler measurements was observed throughout the field trial

  9. Reduction of airborne radioactive dust by means of a charged water spray.

    Science.gov (United States)

    Bigu, J; Grenier, M G

    1989-07-01

    An electrostatic precipitator based on charged water spray technology has been used in an underground uranium mine to control long-lived radioactive dust and short-lived aerosol concentration in a mine gallery where dust from a rock breaking/ore transportation operation was discharged. Two main sampling stations were established: one upstream of the dust precipitator and one downstream. In addition, dust samplers were placed at different locations between the dust discharge and the end of the mine gallery. Long-lived radioactive dust was measured using cascade impactors and nylon cyclone dust samplers, and measurement of the radioactivity on the samples was carried out by conventional methods. Radon and thoron progeny were estimated using standard techniques. Experiments were conducted under a variety of airflow conditions. A maximum radioactive dust reduction of about 40% (approximately 20% caused by gravitational settling) at a ventilation rate of 0.61 m3/sec was obtained as a result of the combined action of water scrubbing and electrostatic precipitation by the charged water spray electrostatic precipitator. This represents the optimum efficiency attained within the range of ventilation rates investigated. The dust reduction efficiency of the charged water spray decreased with increasing ventilation rate, i.e., decreasing air residence time, and hence, reduced dust cloud/charged water droplets mixing time.

  10. Retained gas sampler interim safety assessment

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Retained gas sampler interim safety assessment

    International Nuclear Information System (INIS)

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

    1995-01-01

    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

  12. Organization and effectivity of works on dust suppressing in the special zone of the Chernobyl' NPP

    International Nuclear Information System (INIS)

    Shimin, S.A.; Krapchatov, V.P.; Nad''yarnykh, G.V.; Komarov, V.I.; Andreev, Yu.B.; Samojlenko, Yu.N.

    1989-01-01

    In 1988 three methods of dust suppressing were used: regular watering of roads, chemical treatment of roadsides and dusting sections of area, long-time biologochemical fixation of open sections of area, including sowing with grass and simultaneous treatment by dust-suppressing compositions. Preliminary treatment of objects by polymeric compositions was an effective action to reduce dust-raising. 3 refs.; 3 figs

  13. Direct-reading inhalable dust monitoring--an assessment of current measurement methods.

    Science.gov (United States)

    Thorpe, Andrew; Walsh, Peter T

    2013-08-01

    Direct-reading dust monitors designed specifically to measure the inhalable fraction of airborne dust are not widely available. Current practice therefore often involves comparing the response of photometer-type dust monitors with the concentration measured with a reference gravimetric inhalable sampler, which is used to adjust the dust monitor measurement. However, changes in airborne particle size can result in significant errors in the estimation of inhalable concentration by this method. The main aim of this study was to assess how these dust monitors behave when challenged with airborne dust containing particles in the inhalable size range and also to investigate alternative dust monitors whose response might not be as prone to variations in particle size or that could be adapted to measure inhalable dust concentration. Several photometer-type dust monitors and a Respicon TM, tapered element oscillating microbalance (TEOM) personal dust monitor (PDM) 3600, TEOM 1400, and Dustrak DRX were assessed for the measurement of airborne inhalable dust during laboratory and field trials. The PDM was modified to allow it to sample and measure larger particles in the inhalable size range. During the laboratory tests, the dust monitors and reference gravimetric samplers were challenged inside a large dust tunnel with aerosols of industrial dusts known to present an inhalable hazard and aluminium oxide powders with a range of discrete particle sizes. A constant concentration of each dust type was generated and peak concentrations of larger particles were periodically introduced to investigate the effects of sudden changes in particle size on monitor calibration. The PDM, Respicon, and DataRam photometer were also assessed during field trials at a bakery, joinery, and a grain mill. Laboratory results showed that the Respicon, modified PDM, and TEOM 1400 observed good linearity for all types of dust when compared with measurements made with a reference IOM sampler; the

  14. Stardust Interstellar Preliminary Examination IV: Scanning Transmission X-Ray Microscopy Analyses of Impact Features in the Stardust Interstellar Dust Collector

    Science.gov (United States)

    Butterworth, Anna L.; Westphal, Andrew J.; Frank, David R.; Allen, Carlton C.; Bechtel, Hans A.; Sandford, Scott A.; Tsou, Peter; Zolensky, Michael E.

    2014-01-01

    We report the quantitative characterization by synchrotron soft X-ray spectroscopy of 31 potential impact features in the aerogel capture medium of the Stardust Interstellar Dust Collector. Samples were analyzed in aerogel by acquiring high spatial resolution maps and high energy-resolution spectra of major rock-forming elements Mg, Al, Si, Fe, and others. We developed diagnostic screening tests to reject spacecraft secondary ejecta and terrestrial contaminants from further consideration as interstellar dust candidates. The results support an extraterrestrial origin for three interstellar candidates: I1043,1,30 (Orion) is a 3 pg particle with Mg-spinel, forsterite, and an iron-bearing phase. I1047,1,34 (Hylabrook) is a 4 pg particle comprising an olivine core surrounded by low-density, amorphous Mg-silicate and amorphous Fe, Cr, and Mn phases. I1003,1,40 (Sorok) has the track morphology of a high-speed impact, but contains no detectable residue that is convincingly distinguishable from the background aerogel. Twenty-two samples with an anthropogenic origin were rejected, including four secondary ejecta from impacts on the Stardust spacecraft aft solar panels, nine ejecta from secondary impacts on the Stardust Sample Return Capsule, and nine contaminants lacking evidence of an impact. Other samples in the collection included I1029,1,6, which contained surviving solar system impactor material. Four samples remained ambiguous: I1006,2,18, I1044,2,32, and I1092,2,38 were too dense for analysis, and we did not detect an intact projectile in I1044,3,33. We detected no radiation effects from the synchrotron soft X-ray analyses; however, we recorded the effects of synchrotron hard X-ray radiation on I1043,1,30 and I1047,1,34.

  15. An innovative discrete multilevel sampler design

    International Nuclear Information System (INIS)

    Marvin, B.K.; De Clercq, P.J.; Taylor, B.B.; Mauro, D.M.

    1995-01-01

    An innovative, small-diameter PVC discrete multilevel sampler (DMLS) was designed for the Electric Power Research Institute (EPRI) to provide low-cost, discrete groundwater samples from shallow aquifers. When combined with appropriately-sized direct push soil sampling technologies, high resolution aquifer characterization can be achieved during initial site assessment or remediation monitoring activities. The sampler is constructed from 1-inch diameter PVC well materials, containing polyethylene tubing threaded through PVC disks. Self-expanding annular and internal bentonite seals were developed which isolate discrete sampling zones. The DMLS design allows customization of sampling and isolation zone lengths to suit site-specific goals. Installation of the DMLS is achieved using a temporary, expendable-tipped casting driven by direct push methods. This technique minimizes mobilization costs, site and soil column disturbances, and allows rapid installation in areas of limited overhead clearance. Successful pilot installations of the DMLS prototype have been made at a former manufactured gas plant (MGP) site and a diesel fuel spill site. Analysis of groundwater samples from these sites, using relative compound distributions and contaminant concentration profiling, confirmed that representative discrete samples were collected. This design provides both economical and versatile groundwater monitoring during all phases of site assessment and remediation

  16. Dust observations by PFS on Mars Express

    Science.gov (United States)

    Zasova, L. V.; Formisano, V.; Moroz, V. I.; Grassi, D.; Ignatiev, N. I.; Blecka, M. I.; Maturilli, A.; Palomba, E.; Piccioni, G.; Pfs Team

    Dust is always present in the Martian atmosphere with opacity, which changes from values below 0.1 (at 9 μ m) up to several units during the dust storms. From the thermal IR (LW channel of PFS) the dust opacity is retrieved in a self consistent way together with the temperature profile from the same spectrum A preliminary investigation along the orbit, which comes through Hellas, shows that the value of dust opacity anticorrelates with surface altitude. From -70 to +25 of latitude the vertical dust distribution follows the exponential low with the scale of 12 km, which corresponds to the gaseous scale height near noon and indicates for well mixed condition. The dust opacity, corresponding to the zero surface altitude, is found of 0.25+-0.05. More detailed investigations of all available data will be presented, including analysis of both short- and long- wavelength spectra of PFS.

  17. Performance characteristics of a low-volume PM10 sampler

    Science.gov (United States)

    Four identical PM10 pre-separators, along with four identical low-volume (1m3 hr-1) total suspended particulate (TSP) samplers were tested side-by-side in a controlled laboratory particulate matter (PM) chamber. The four PM10 and four TSP samplers were also tested in an oil pipe-cleaning field to ev...

  18. A radon progeny sampler for the determination of effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, S.B. [Australian Radiation Laboratory, Victoria (Australia)

    1997-12-01

    The design and simulated performance is described of a two-stage sampler (HE-Sampler) for {sup 222}Rn progeny. This HE-Sampler has a collection efficiency optimised to match the particle size dependency of the radon progeny dose conversion factor (DCF), derived from the latest Respiratory Tract Model of the International Commission on Radiological Protection, as implemented in the computer code RADEP. The He-Sampler comprises a wire screen pre-separator, matched to the nasal deposition, and a wire screen collector, matched to the respiratory tract collection. This HE-Sampler allows for the estimation of the radiation dose from the inhalation of {sup 222}Rn progeny, derived from two concurrent alpha particle activity measurements, one on the HE-Sampler screen collector and one on a reference filter sample. As a first approximation, the DCF is proportional to the collected fraction. The HE-Sampler response was simulated for a range of radon progeny size distributions to determine the error in the estimated DCF values. The simulation results show that the HE-Sampler is relatively insensitive to variations in sampling rate and in the screen parameters, particularly for environmental exposure. (Author).

  19. Optimal relaxed causal sampler using sampled-date system theory

    NARCIS (Netherlands)

    Shekhawat, Hanumant; Meinsma, Gjerrit

    This paper studies the design of an optimal relaxed causal sampler using sampled data system theory. A lifted frequency domain approach is used to obtain the existence conditions and the optimal sampler. A state space formulation of the results is also provided. The resulting optimal relaxed causal

  20. Passive sampler for dissolved organic matter in freshwater environments.

    Science.gov (United States)

    Lam, Buuan; Simpson, André J

    2006-12-15

    A passive sampler for the isolation of dissolved organic matter (DOM) from freshwater environments is described. The sampler consists of a molecular weight selective membrane (1000 kDa) and an anion exchange resin (diethylaminoethylcellulose (DEAE-cellulose)). NMR indicates the samplers isolate DOM that is nearly indistinguishable from that isolated using the batch DEAE-cellulose procedure. In a comparative study DOM isolated from Lake Ontario cost approximately 0.30 dollars/mg to isolate using the passive samplers while DOM isolated using the traditional batch procedure cost approximately 8-10 dollars/mg. The samplers have been shown to be effective in a range of freshwater environments including a large inland lake (Lake Ontario), fast flowing tributary, and wetland. Large amounts (gram quantities of DOM) can be easily isolated by increasing the size or number of samplers deployed. Samplers are easy to construct, negate the need for pressure filtering, and also permit a range of temporal and spatial experiments that would be very difficult or impossible to perform using conventional approaches. For example, DOM can be monitored on a regular basis at numerous different locations, or samplers could be set at different depths in large lakes. Furthermore, they could potentially be deployed into hard to reach environments such as wells, groundwater aquifers, etc., and as they are easy to use, they can be mailed to colleagues or included with expeditions going to difficult to reach places such as the Arctic and Antarctic.

  1. The distribution of interstellar dust

    International Nuclear Information System (INIS)

    Clocchiatti, A.; Marraco, H.G.

    1986-01-01

    We propose the interstellar matter structural function as a tool to derive the features of the interstellar dust distribution. We study that function resolving some ideal dust distribution models. Later we describe the method used to find a reliable computing algorithm for the observational case. Finally, we describe the steps to build a model for the interstellar matter composed by spherically symmetrical clouds. The density distribution for each of these clouds is D(r) = D 0 .esup(-r/r 0 ) 2 . The preliminary results obtained are summarised. (author)

  2. Siting Samplers to Minimize Expected Time to Detection

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Four Interstellar Dust Candidates from the Stardust Interstellar Dust Collector

    Science.gov (United States)

    Westphal, A. J.; Allen, C.; Bajt, S.; Bechtel, H. A.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; Burchell, M.; Burghammer, M.; hide

    2011-01-01

    In January 2006, the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, Comet 81P/Wild2, and a collector dedicated to the capture and return of contemporary interstellar dust. Both collectors were approx. 0.1 sq m in area and were composed of aerogel tiles (85% of the collecting area) and aluminum foils. The Stardust Interstellar Dust Collector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 sq m/day. The Stardust Interstellar Preliminary Examination (ISPE) is a consortium-based project to characterize the collection using nondestructive techniques. The goals and restrictions of the ISPE are described . A summary of analytical techniques is described.

  4. BCE selector valves and flow proportional sampler

    International Nuclear Information System (INIS)

    Rippy, G.L.

    1994-01-01

    This Acceptance Test Procedure (ATP) has been prepared to demonstrate that the Electrical/Instrumentation systems for the B-Plant Process Condensate Treatment Facility (BCE) function as required by project criteria. Tests will be run to: Verify the operation of the solenoid valve and associated limit switches installed for the BCE portion of W-007H; Operate the solenoid valve and verify the proper operation of the associated limit switches based on the position of the solenoid valve;and, Demonstrate the integrity of the Sample Failure Alarm Relay XFA-211BA-BCE-1, and Power Failure ALarm Relay JFA-211BA-BCE-1 located inside the Flow Proportional Sampler in Building 211 BA

  5. Multipurpose sampler device for liquid metal

    International Nuclear Information System (INIS)

    Nelson, P.A.; Kolba, V.M.; Holmes, J.T.

    1975-01-01

    A device for collecting samples or examining a flow of liquid metal is provided for use with such as a liquid-metal-cooled nuclear reactor. The sampler device includes a casing surrounded by an external heater for establishing an upper isothermal zone and a lower zone for heating the entering liquid metal. One of various inserts is suspended into the isothermal zone where it is surrounded by a shroud tube for directing liquid-metal flow from the heating zone into the top of the insert. Discharge flow from the insert gravitates through a helically wound tube in heat exchange contact with entering liquid-metal flow within the heating zone. The inserts comprise an overflow cup with upper and lower freeze seals, a filter for removing particulate matter, and a fixture for maintaining various sample materials in equilibrium with liquid-metal flow. (U.S.)

  6. Dust coma of Halley comet: measurements with the dust counter and mass analyzer (DUSMA)

    International Nuclear Information System (INIS)

    Simpson, J.A.; Sagdeev, R.Z.; Tuzzolino, A.J.; AN SSSR, Moscow. Inst. Kosmicheskikh Issledovanij)

    1986-01-01

    The paper represents a preliminary report on measurements of spatial and temporal distribution of mass and flows of dust particles coming from comet nucleus performed by means of devices constructed on the new principle of detecting comet dust specks. The device has a high time resolution (∼ 4 μs) in the wide range of mass and dust flows. On the base of a preliminary analysis the following conclusions are drawn: dust coma in quiet state (''Vega-2'') as well as at the presence of considerable emissions (''Vega-1'') manifests the presence of important short-term out-bursts having by time a quasi-periodic structure. Integral mass spectra show flows intensity growth with the decrease of measured mass (which contradicts some theoretical models). Flow levels lie approximately in the region previously determined by ground observations. The coma is extremely dynamic both in space and in time which proves the complex structure of regions of dust emission from the nucleus

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

    DEFF Research Database (Denmark)

    Uhrbrand, Katrine; Kalevi Koponen, Ismo; Schultz, Anna Charlotte

    2017-01-01

    V. Sampling was performed using a nylon (NY) filter in conjunction with four kinds of personal samplers; Gesamtstaubprobenahme sampler (GSP), Triplex-cyclone sampler (TC), 3-piece closed-faced Millipore cassette (3P) and a 2-stage NIOSH cyclone sampler (NIO). In addition, sampling was performed using the GSP...

  8. Concentration and movement of neonicotinoids as particulate matter downwind during agricultural practices using air samplers in southwestern Ontario, Canada.

    Science.gov (United States)

    Forero, Luis Gabriel; Limay-Rios, Victor; Xue, Yingen; Schaafsma, Arthur

    2017-12-01

    Atmospheric emissions of neonicotinoid seed treatment insecticides as particulate matter in field crops occur mainly for two reasons: 1) due to abraded dust of treated seed generated during planting using vacuum planters, and 2) as a result of disturbances (tillage or wind events) in the surface of parental soils which release wind erodible soil-bound residues. In the present study, concentration and movement of neonicotinoids as particulate matter were quantified under real conditions using passive and active air samplers. Average neonicotinoid concentrations in Total Suspended Particulate (TSP) using passive samplers were 0.48 ng/cm 2 , trace, trace (LOD 0.80 and 0.04 ng/cm 2 for clothianidin and thiamethoxam, respectively), and using active samplers 16.22, 1.91 and 0.61 ng/m 3 during planting, tillage and wind events, respectively. There was a difference between events on total neonicotinoid concentration collected in particulate matter using either passive or active sampling. Distance of sampling from the source field during planting of treated seed had an effect on total neonicotinoid air concentration. However, during tillage distance did not present an effect on measured concentrations. Using hypothetical scenarios, values of contact exposure for a honey bee were estimated to be in the range from 1.1% to 36.4% of the reference contact LD 50 value of clothianidin of 44 ng/bee. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Automated particulate sampler field test model operations guide

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Europa Drum Sampler (EDuS), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The main objective of the proposed work is to develop a robust and effective sample acquisition system for the Europa lander called the Europa Drum Sampler (EDuS)....

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

    Science.gov (United States)

    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.

  12. Assessment of occupational exposure to wood dust in the Polish furniture industry

    Directory of Open Access Journals (Sweden)

    Małgorzata Szewczyńska

    2017-02-01

    Full Text Available Background: Occupational exposure to wood dust can be responsible for many different harmful health effects, especially in workers employed in the wood industry. The assessment of wood dust adverse effects to humans, as well as the interpretation of its concentration measurements carried out to assess potential occupational exposure are very difficult. First of all, it is due to possible occurrence of different kind of wood dust in the workplace air, namely wood dust from dozens of species of trees belonging to 2 kinds of botanical gymnosperms and angiosperms, as well as to its different chemical composition. Material and Methods: Total dust and respirable wood dust in the workplace air in the furniture industry was determined using the filtration-gravimetric method in accordance with Polish Standards PN-Z-04030-05:1991 and PN-Z-04030-06:1991. Air samples were collected based on the principles of individual dosimetry. Results: Total dust concentrations were 0.84–13.92 mg/m3 and inhalable fraction concentrations, obtained after the conversion of total dust by applying a conversion factor of 1.59, were 1.34–22.13 mg/m3. Respirable fraction concentrations were 0.38–4.04 mg/m3, which makes approx. 25% of the inhalable fraction on average. The highest concentrations occurred in grinding and the lowest during milling processes of materials used in the manufacture of furniture. Conclusions: The results indicate that the share of respirable fraction in the inhalable fraction of wood dust is considerable. Due to the determination of the threshold limit value (TLV for the inhalable fraction of wood dust, it is necessary to replace the previously used samplers for total dust with samplers that provide quantitative separation of wood dust inhalable fractions in accordance with the convention of this fraction as defined in PN-EN 481:1998. Med Pr 2017;68(1:45–60

  13. Transient digitizer with displacement current samplers

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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%. © 2013 Elsevier B.V. All rights reserved.

  15. Characterization of respirable mine dust and diesel particulate matter

    CSIR Research Space (South Africa)

    Mahlangu, Vusi J

    2015-11-01

    Full Text Available This paper presents the preliminary outcomes to develop and optimize methods to characterize DPM and respirable dust samples for the following: Crystalline compounds Common mineral analyses Particle size distribution Elemental Carbon (EC...

  16. Task plan for test of PRBT prototypic liquid sampler

    International Nuclear Information System (INIS)

    Jenkins, W.J.

    1992-01-01

    The primary objective of this task is to determine just how representative Precipitate Reactor Bottom Tank (PRBT) samples taken from the Hydragard trademark prototypic liquid sampler are of the in-tank contents and also to determine the homogeneity of the in-tank contents. This shall be accomplished by a statistical design study sampling plan for paired contrasts of the analysis results of samples taken from: (1) the Hydragard trademark prototypic liquid sampler paired with the more fundamental grab sampler at the lower elevation for the Hydragard trademark prototypic liquid sampler accuracy and (2) the grab sampler at the lower elevation paired with the grab sampler at the upper elevation for the in-tank homogeneity. These measurements are paired together to sharpen the contrast so that, as nearly as possible, only the conditions of the effect under study will differ between the two. This ''split-plot'' arrangement provides increased precision for the contrast under study by canceling out common extraneous effects, thereby enabling the detection of smaller effects. The secondary objective of the task is to determine the level of influence of the major contributors to the overall uncertainty in the sample preparation and measurement process. These major steps include: preparation method (H 2 SO 4 -HF Titanium dissolution); aliquoting and dilution within a dissolution; measurement and long-term behavior of the ICP and AA instruments, as monitored by the measurement of standards and blanks embedded within each block of samples for the measurement sequence. This sampling task, therefore, is mostly devoted to determining the sampler characteristics and is not intended to provide a comprehensive estimate of the overall uncertainty affecting DWPF sample analysis in routine operation

  17. Studies on airborne dust particles by neutron activation analysis

    International Nuclear Information System (INIS)

    Aoki, Atsushi; Ishii, Taka; Tomiyama, Tsuyoshi; Yamamoto, Isao.

    1974-01-01

    Neutron activation analysis was performed on the airborne dust particles collected at six places with different contaminating circumstances in Kyoto city and the suburbs of Okayama city, using an open type low volume air sampler with a membrance filter attached. Radioactivation by neutrons was performed with the reactor in the Research Reactor Institute of Kyoto University. Short half-life nuclides activated by thermal neutrons were measured. The concentration of airborne dust was usually high in November and December, while Na, Mn, K, etc. probably owing to soil origin showed similar seasonal change to the dust particles, as expected. The concentrations Cl and Br were in proportion to traffic volume, and it was considered to be caused by the exhaust gas from cars. Zn, V. et. were thick in factory areas, which seemed to show the relationship with oil fuel consumption. (Kobatake, H.)

  18. Dust Measurements in Tokamaks

    International Nuclear Information System (INIS)

    Rudakov, D; Yu, J; Boedo, J; Hollmann, E; Krasheninnikov, S; Moyer, R; Muller, S; Yu, A; Rosenberg, M; Smirnov, R; West, W; Boivin, R; Bray, B; Brooks, N; Hyatt, A; Wong, C; Fenstermacher, M; Groth, M; Lasnier, C; McLean, A; Stangeby, P; Ratynskaia, S; Roquemore, A; Skinner, C; Solomon, W M

    2008-01-01

    Dust production and accumulation impose safety and operational concerns for ITER. Diagnostics to monitor dust levels in the plasma as well as in-vessel dust inventory are currently being tested in a few tokamaks. Dust accumulation in ITER is likely to occur in hidden areas, e.g. between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering resolves size of particles between 0.16-1.6 (micro)m in diameter; the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast-framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in 2D with a single camera or 3D using multiple cameras, but determination of particle size is problematic. In order to calibrate diagnostics and benchmark dust dynamics modeling, pre-characterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase of carbon atomic, C2 dimer, and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics

  19. Evaluation of PM-10 commercial inlets for new surveillance air sampler

    International Nuclear Information System (INIS)

    Langer, G.

    1986-01-01

    The inlet for the present Rock Flats Plant surveillance sampler does not meet the new but still tentative PM-10 (<10-μm particle mass) criterion for sampling the hazardous fraction of airborne dust. Since this criterion relates mainly to non-radioactive emissions, DOE and EPA are presently in the process of promulgating emission guidelines specifically for non-reactor DOE nuclear facilities. The authors present approach is to select a commercial inlet and modify its, if necessary, to meet the PM-10 criterion, keeping in mind that they may have to recover the dust collected in the inlet. There is no EPA-approved PM-10 inlet design; instead, EPA issued a performance specification. As a nuclear operation, Rocky Flats has to sample continuously to ensure no period remains unmonitored, instead of every sixth day, as set forth by EPA for non-nuclear installations. During this study period, the authors developed an inlet evaluation methodology to meet the above, anticipated EPA requirements. Also, they started testing two potential inlets. 6 references, 2 figures, 1 table

  20. 'Nuisance Dust' - a Case for Recalibration?

    Science.gov (United States)

    Datson, Hugh; Marker, Brian

    2013-04-01

    time). 'Custom and practice' acceptance criteria for dust samples obtained by mass or soiling techniques have been developed and are widely applied even though they were not necessarily calibrated thoroughly and have not been reviewed recently. Furthermore, as sampling techniques have evolved, criteria developed for one method have been adapted for another. Criteria and limit values have sometimes been based on an insufficient knowledge of sampler characteristics. Ideally, limit values should be calibrated for the locality to take differences in dust density and visibility into account. Work is needed on the definition of criteria and limit values, and sampling practices for coarse dust fractions, followed by discussion of good practices for securing effective monitoring that is proportionate and fit for purpose. With social changes and the evolution of environmental controls since the 1960s, the public perception of 'nuisance dust' has changed and needs to be addressed by reviewing existing thresholds in relation to the range of monitoring devices currently in use.

  1. The neighborhood MCMC sampler for learning Bayesian networks

    Science.gov (United States)

    Alyami, Salem A.; Azad, A. K. M.; Keith, Jonathan M.

    2016-07-01

    Getting stuck in local maxima is a problem that arises while learning Bayesian networks (BNs) structures. In this paper, we studied a recently proposed Markov chain Monte Carlo (MCMC) sampler, called the Neighbourhood sampler (NS), and examined how efficiently it can sample BNs when local maxima are present. We assume that a posterior distribution f(N,E|D) has been defined, where D represents data relevant to the inference, N and E are the sets of nodes and directed edges, respectively. We illustrate the new approach by sampling from such a distribution, and inferring BNs. The simulations conducted in this paper show that the new learning approach substantially avoids getting stuck in local modes of the distribution, and achieves a more rapid rate of convergence, compared to other common algorithms e.g. the MCMC Metropolis-Hastings sampler.

  2. A constant flow filter air sampler for workplace environments

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  3. A mathematics sampler topics for the liberal arts

    CERN Document Server

    Berlinghoff, William P; Skrien, Dale

    2001-01-01

    Now in its fifth edition, A Mathematics Sampler presents mathematics as both science and art, focusing on the historical role of mathematics in our culture. It uses selected topics from modern mathematics-including computers, perfect numbers, and four-dimensional geometry-to exemplify the distinctive features of mathematics as an intellectual endeavor, a problem-solving tool, and a way of thinking about the rapidly changing world in which we live. A Mathematics Sampler also includes unique LINK sections throughout the book, each of which connects mathematical concepts with areas of interest th

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

    Science.gov (United States)

    Objectives. This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Approach/Activities. Fifty-five studies were found where both passive sampler uptake...

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

    Science.gov (United States)

    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.

  6. Reuter Centrifugal Air Sampler: Measurement of Effective Airflow Rate and Collection Efficiency

    OpenAIRE

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

    1983-01-01

    Incorrect calculation of effective air sampling rate and disregard of differences in collection efficiency among samplers can lead to false conclusions about the usefulness of samplers for measuring concentrations of airborne microorganisms.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Development of a personal multi-pollutant exposure sampler for particulate matter and criteria gases

    Energy Technology Data Exchange (ETDEWEB)

    Chang, I.T.; Sarnat, J.; Wolfson, J.M.; Rojas-Bracho, L.; Suh, H.H.; Koutrakis, P. [Harvard Univ., Boston, MA (United States). School of Public Health

    1999-12-01

    A novel personal sampler is reported which allows simultaneous measurement of PM{sub 2,5}, and PM{sub 10}, ozone, nitrogen dioxide, and sulfur dioxide. This method combines previously used samplers for personal mass measurement with passive samplers for criteria gases and uses a single pump. Preliminarily results are reported for laboratory chamber tests and field comparisons with reference methods for both mass and criteria gases. These results demonstrate the suitability of this sampler of exposure assessment studies. (authors)

  9. 50 CFR 697.12 - At-sea sea sampler/observer coverage.

    Science.gov (United States)

    2010-10-01

    ... sampler/observer access to and use of the vessel's communications equipment and personnel upon request for...) Allow the sea sampler/observer to inspect and copy the vessel's log, communications log, and records... must: (1) Notify the sea sampler/observer of any sea turtles, marine mammals, or other specimens taken...

  10. An analysis of the dust deposition on solar photovoltaic modules.

    Science.gov (United States)

    Styszko, Katarzyna; Jaszczur, Marek; Teneta, Janusz; Hassan, Qusay; Burzyńska, Paulina; Marcinek, Ewelina; Łopian, Natalia; Samek, Lucyna

    2018-03-29

    Solid particles impair the performance of the photovoltaic (PV) modules. This results in power losses which lower the efficiency of the system as well as the increases of temperature which additionally decreases the performance and lifetime. The deposited dust chemical composition, concentration and formation of a dust layer on the PV surface differ significantly in reference to time and location. In this study, an evaluation of dust deposition on the PV front cover glass during the non-heating season in one of the most polluted European cities, Kraków, was performed. The time-dependent particle deposition and its correlation to the air pollution with particulate matter were analysed. Dust deposited on several identical PV modules during variable exposure periods (from 1 day up to 1 week) and the samples of total suspended particles (TSP) on quartz fibre filters using a low volume sampler were collected during the non-heating season in the period of 5 weeks. The concentration of TSP in the study period ranged between 12.5 and 60.05 μg m -3 while the concentration of PM10 observed in the Voivodeship Inspectorate of Environmental Protection traffic station, located 1.2 km from the TSP sampler, ranged from 14 to 47 μg m -3 . It was revealed that dust deposition density on a PV surface ranged from 7.5 to 42.1 mg m -2 for exposure periods of 1 day while the measured weekly dust deposition densities ranged from 25.8 to 277.0 mg m -2 . The precipitation volume and its intensity as well as humidity significantly influence the deposited dust. The rate of dust accumulation reaches approximately 40 mg m -2 day -1 in the no-precipitation period and it was at least two times higher than fluxes calculated on the basis of PM10 and TSP concentrations which suggest that additional forces such as electrostatic forces significantly influence dust deposition.

  11. Developments in Emission Measurements Using Lightweight Sensors and Samplers.

    Science.gov (United States)

    Lightweight emission measurement systems making use of miniaturized sensors and samplers have been developed for portable and aerial sampling for an array of pollutants. Shoebox-sized systems called “Kolibri”, weighing 3-5 kg, have been deployed on NASA-flown unmanned...

  12. Operability test procedure for 211BA flow proportional sampler

    International Nuclear Information System (INIS)

    Weissenfels, R.D.

    1994-01-01

    The purpose of this operability test procedure (OTP) is to verify the 211-BA flow proportional sampler system and components function correctly as intended by design. System test will include the sampling system, all associated instrumentation, and Facility Process Monitor and Control System (FPMCS). The combined chemical sewer stream from B Plant flows through sump 211BA-SMP-01 located in 211-BA and is continuously monitored for gamma and beta radiation and pH. 211-BA has been upgraded to include a flow proportional sampler. A specified sample volume will be withdrawn at programmed intervals from the 211BA sump and deposited in a 19 liter plastic carboy. The sampler will be programmed per the vendor installation and operations manual by B Plant instrument maintenance personnel. Samples will be taken during five consecutive sample cycles with the sample volumes and sample frequencies recorded for comparison purposes. Additional tests related to the sampler include the alarm circuitry for loss of power and failure to obtain sample

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

    International Nuclear Information System (INIS)

    1999-01-01

    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.

  14. Observation of 45 GHz current waveforms using HTS sampler

    International Nuclear Information System (INIS)

    Maruyama, M.; Suzuki, H.; Hato, T.; Wakana, H.; Nakayama, K.; Ishimaru, Y.; Horibe, O.; Adachi, S.; Kamitani, A.; Suzuki, K.; Oshikubo, Y.; Tarutani, Y.; Tanabe, K.

    2005-01-01

    We succeeded in observing high-frequency current waveforms up to 45 GHz using a high-temperature superconducting (HTS) sampler. In this experiment, we used a sampler circuit with a superconducting pickup coil, which magnetically detects current signals flowing through a micro-strip line on a printed board placed outside the cryochamber. This type of measurement enables non-contact current-waveform observation that seems useful for analyses of EMI, defects in LSI, etc. Computer simulation reveals that one of our latest versions of HTS sampler circuits having Josephson transmission lines with optimized biases as buffers has a potential of sampling high-frequency signals with a bandwidth above 100 GHz. To realize the circuit parameters required in the simulations, we developed an HTS circuit fabrication process employing a lower ground plane structure with SrSnO 3 insulating layers. We consider that improvement of the circuit fabrication process and optimization of the pickup coil lead to much higher signal frequency observable by the sampler

  15. Pebble Bed Reactor Dust Production Model

    Energy Technology Data Exchange (ETDEWEB)

    Abderrafi M. Ougouag; Joshua J. Cogliati

    2008-09-01

    The operation of pebble bed reactors, including fuel circulation, can generate graphite dust, which in turn could be a concern for internal components; and to the near field in the remote event of a break in the coolant circuits. The design of the reactor system must, therefore, take the dust into account and the operation must include contingencies for dust removal and for mitigation of potential releases. Such planning requires a proper assessment of the dust inventory. This paper presents a predictive model of dust generation in an operating pebble bed with recirculating fuel. In this preliminary work the production model is based on the use of the assumption of proportionality between the dust production and the normal force and distance traveled. The model developed in this work uses the slip distances and the inter-pebble forces computed by the authors’ PEBBLES. The code, based on the discrete element method, simulates the relevant static and kinetic friction interactions between the pebbles as well as the recirculation of the pebbles through the reactor vessel. The interaction between pebbles and walls of the reactor vat is treated using the same approach. The amount of dust produced is proportional to the wear coefficient for adhesive wear (taken from literature) and to the slip volume, the product of the contact area and the slip distance. The paper will compare the predicted volume with the measured production rates. The simulation tallies the dust production based on the location of creation. Two peak production zones from intra pebble forces are predicted within the bed. The first zone is located near the pebble inlet chute due to the speed of the dropping pebbles. The second peak zone occurs lower in the reactor with increased pebble contact force due to the weight of supported pebbles. This paper presents the first use of a Discrete Element Method simulation of pebble bed dust production.

  16. Pebble Bed Reactor Dust Production Model

    International Nuclear Information System (INIS)

    Abderrafi M. Ougouag; Joshua J. Cogliati

    2008-01-01

    The operation of pebble bed reactors, including fuel circulation, can generate graphite dust, which in turn could be a concern for internal components; and to the near field in the remote event of a break in the coolant circuits. The design of the reactor system must, therefore, take the dust into account and the operation must include contingencies for dust removal and for mitigation of potential releases. Such planning requires a proper assessment of the dust inventory. This paper presents a predictive model of dust generation in an operating pebble bed with recirculating fuel. In this preliminary work the production model is based on the use of the assumption of proportionality between the dust production and the normal force and distance traveled. The model developed in this work uses the slip distances and the inter-pebble forces computed by the authors PEBBLES. The code, based on the discrete element method, simulates the relevant static and kinetic friction interactions between the pebbles as well as the recirculation of the pebbles through the reactor vessel. The interaction between pebbles and walls of the reactor vat is treated using the same approach. The amount of dust produced is proportional to the wear coefficient for adhesive wear (taken from literature) and to the slip volume, the product of the contact area and the slip distance. The paper will compare the predicted volume with the measured production rates. The simulation tallies the dust production based on the location of creation. Two peak production zones from intra pebble forces are predicted within the bed. The first zone is located near the pebble inlet chute due to the speed of the dropping pebbles. The second peak zone occurs lower in the reactor with increased pebble contact force due to the weight of supported pebbles. This paper presents the first use of a Discrete Element Method simulation of pebble bed dust production

  17. Evaluation of IOM personal sampler at different flow rates.

    Science.gov (United States)

    Zhou, Yue; Cheng, Yung-Sung

    2010-02-01

    The Institute of Occupational Medicine (IOM) personal sampler is usually operated at a flow rate of 2.0 L/min, the rate at which it was designed and calibrated, for sampling the inhalable mass fraction of airborne particles in occupational environments. In an environment of low aerosol concentrations only small amounts of material are collected, and that may not be sufficient for analysis. Recently, a new sampling pump with a flow rate up to 15 L/min became available for personal samplers, with the potential of operating at higher flow rates. The flow rate of a Leland Legacy sampling pump, which operates at high flow rates, was evaluated and calibrated, and its maximum flow was found to be 10.6 L/min. IOM samplers were placed on a mannequin, and sampling was conducted in a large aerosol wind tunnel at wind speeds of 0.56 and 2.22 m/s. Monodisperse aerosols of oleic acid tagged with sodium fluorescein in the size range of 2 to 100 microm were used in the test. The IOM samplers were operated at flow rates of 2.0 and 10.6 L/min. Results showed that the IOM samplers mounted in the front of the mannequin had a higher sampling efficiency than those mounted at the side and back, regardless of the wind speed and flow rate. For the wind speed of 0.56 m/s, the direction-averaged (the average value of all orientations facing the wind direction) sampling efficiency of the samplers operated at 2.0 L/min was slightly higher than that of 10.6 L/min. For the wind speed of 2.22 m/s, the sampling efficiencies at both flow rates were similar for particles < 60 microm. The results also show that the IOM's sampling efficiency at these two different flow rates follows the inhalable mass curve for particles in the size range of 2 to 20 microm. The test results indicate that the IOM sampler can be used at higher flow rates.

  18. LADEE LUNAR DUST EXPERIMENT

    Data.gov (United States)

    National Aeronautics and Space Administration — This archive bundle includes data taken by the Lunar Dust Experiment (LDEX) instrument aboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft....

  19. Construction dust amelioration techniques.

    Science.gov (United States)

    2012-04-01

    Dust produced on seasonal road construction sites in Alaska is both a traffic safety and environmental concern. Dust emanating from : unpaved road surfaces during construction severely reduces visibility and impacts stopping sight distance, and contr...

  20. On Dust Charging Equation

    OpenAIRE

    Tsintsadze, Nodar L.; Tsintsadze, Levan N.

    2008-01-01

    A general derivation of the charging equation of a dust grain is presented, and indicated where and when it can be used. A problem of linear fluctuations of charges on the surface of the dust grain is discussed.

  1. Physics of interstellar dust

    CERN Document Server

    Krugel, Endrik

    2002-01-01

    The dielectric permeability; How to evaluate grain cross sections; Very small and very big particles; Case studies of Mie calculus; Particle statistics; The radiative transition probability; Structure and composition of dust; Dust radiation; Dust and its environment; Polarization; Grain alignment; PAHs and spectral features of dust; Radiative transport; Diffuse matter in the Milky Way; Stars and their formation; Emission from young stars. Appendices Mathematical formulae; List of symbols.

  2. Dust as a surfactant

    International Nuclear Information System (INIS)

    Ignatov, A M; Schram, P P J M; Trigger, S A

    2003-01-01

    We argue that dust immersed in a plasma sheath acts as a surfactant. By considering the momentum balance in a plasma sheath, we evaluate the dependence of the plasma surface pressure on the dust density. It is shown that the dust may reduce the surface pressure, giving rise to a sufficiently strong tangential force. The latter is capable of confining the dust layer inside the sheath in the direction perpendicular to the ion flow

  3. FINDING WAYS OF RECYCLING DUST OF ARC STEEL FURNACES AT THE BELARUSIAN METALLURGIC PLANT. PART 3. EXPERIMENTS ON BRIQUETTING OF DUST OFARC STEEL FURNACES

    Directory of Open Access Journals (Sweden)

    A. I. Rozhkov

    2015-01-01

    Full Text Available The article gives an overview of the global experience of recycling dust by briquetting. The advantages and disadvantages of recycling dust with its preliminary briquetting are described. Information about experiments on briquetting of dust generated in different organizations of the Belarusian metallurgy plant with various binders is given. Economic calculations were performed on the basis of technical data obtained during the manufacture of prototypes of briquettes. The results of the calculations showedinexpediency of recycling dust briquetting method because of the low iron content in the dust, high cost of binder and a relatively small rate of ecological tax.

  4. Estimation of the Human Extrathoracic Deposition Fraction of Inhaled Particles Using a Polyurethane Foam Collection Substrate in an IOM Sampler

    Directory of Open Access Journals (Sweden)

    Darrah K. Sleeth

    2016-03-01

    Full Text Available Extrathoracic deposition of inhaled particles (i.e., in the head and throat is an important exposure route for many hazardous materials. Current best practices for exposure assessment of aerosols in the workplace involve particle size selective sampling methods based on particle penetration into the human respiratory tract (i.e., inhalable or respirable sampling. However, the International Organization for Standardization (ISO has recently adopted particle deposition sampling conventions (ISO 13138, including conventions for extrathoracic (ET deposition into the anterior nasal passage (ET1 and the posterior nasal and oral passages (ET2. For this study, polyurethane foam was used as a collection substrate inside an inhalable aerosol sampler to provide an estimate of extrathoracic particle deposition. Aerosols of fused aluminum oxide (five sizes, 4.9 µm–44.3 µm were used as a test dust in a low speed (0.2 m/s wind tunnel. Samplers were placed on a rotating mannequin inside the wind tunnel to simulate orientation-averaged personal sampling. Collection efficiency data for the foam insert matched well to the extrathoracic deposition convention for the particle sizes tested. The concept of using a foam insert to match a particle deposition sampling convention was explored in this study and shows promise for future use as a sampling device.

  5. Estimation of the Human Extrathoracic Deposition Fraction of Inhaled Particles Using a Polyurethane Foam Collection Substrate in an IOM Sampler.

    Science.gov (United States)

    Sleeth, Darrah K; Balthaser, Susan A; Collingwood, Scott; Larson, Rodney R

    2016-03-07

    Extrathoracic deposition of inhaled particles (i.e., in the head and throat) is an important exposure route for many hazardous materials. Current best practices for exposure assessment of aerosols in the workplace involve particle size selective sampling methods based on particle penetration into the human respiratory tract (i.e., inhalable or respirable sampling). However, the International Organization for Standardization (ISO) has recently adopted particle deposition sampling conventions (ISO 13138), including conventions for extrathoracic (ET) deposition into the anterior nasal passage (ET₁) and the posterior nasal and oral passages (ET₂). For this study, polyurethane foam was used as a collection substrate inside an inhalable aerosol sampler to provide an estimate of extrathoracic particle deposition. Aerosols of fused aluminum oxide (five sizes, 4.9 µm-44.3 µm) were used as a test dust in a low speed (0.2 m/s) wind tunnel. Samplers were placed on a rotating mannequin inside the wind tunnel to simulate orientation-averaged personal sampling. Collection efficiency data for the foam insert matched well to the extrathoracic deposition convention for the particle sizes tested. The concept of using a foam insert to match a particle deposition sampling convention was explored in this study and shows promise for future use as a sampling device.

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

    International Nuclear Information System (INIS)

    Liden, Goeran; Surakka, Jouni

    2009-01-01

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

  7. Methods for measuring the emission of dust in the air from the industrial objects

    International Nuclear Information System (INIS)

    Petsovska-Gjorgjevich, M.

    2006-01-01

    Two methods are used for measuring the emission of dust in the air from the industrial objects. The first is gravimetrical method, measuring of particular matter in flowing gases, using GRAVIMAT SHC 502 sampler, and the second is optoelectronic method working with the transmission light principle with extinction output, using OMD 41 in-situ dust monitor. Both methods are explained theoretically and the probe measurement is fulfilled for one of our industrial objects. The two methods are connected, because of the necessity of the implementation of the results from the first measurements in the second ones which are continual for long time. (Author)

  8. A Comparison of "Total Dust" and Inhalable Personal Sampling for Beryllium Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Colleen M. [Tulane Univ., New Orleans, LA (United States). School of Public Health and Tropical Medicine

    2012-05-09

    In 2009, the American Conference of Governmental Industrial Hygienists (ACGIH) reduced the Beryllium (Be) 8-hr Time Weighted Average Threshold Limit Value (TLV-TWA) from 2.0 μg/m3 to 0.05 μg/m3 with an inhalable 'I' designation in accordance with ACGIH's particle size-selective criterion for inhalable mass. Currently, per the Department of Energy (DOE) requirements, the Lawrence Livermore National Laboratory (LLNL) is following the Occupational Health and Safety Administration (OSHA) Permissible Exposure Limit (PEL) of 2.0 μg/m3 as an 8-hr TWA, which is also the 2005 ACGIH TLV-TWA, and an Action Level (AL) of 0.2 μg/m3 and sampling is performed using the 37mm (total dust) sampling method. Since DOE is considering adopting the newer 2009 TLV guidelines, the goal of this study was to determine if the current method of sampling using the 37mm (total dust) sampler would produce results that are comparable to what would be measured using the IOM (inhalable) sampler specific to the application of high energy explosive work at LLNL's remote experimental test facility at Site 300. Side-by-side personal sampling using the two samplers was performed over an approximately two-week period during chamber re-entry and cleanup procedures following detonation of an explosive assembly containing Beryllium (Be). The average ratio of personal sampling results for the IOM (inhalable) vs. 37-mm (total dust) sampler was 1.1:1 with a P-value of 0.62, indicating that there was no statistically significant difference in the performance of the two samplers. Therefore, for the type of activity monitored during this study, the 37-mm sampling cassette would be considered a suitable alternative to the IOM sampler for collecting inhalable particulate matter, which is important given the many practical and economic advantages that it presents. However, similar comparison studies would be necessary for this conclusion to be

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

    Science.gov (United States)

    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).

  10. Development and evaluation of an ultrasonic personal aerosol sampler.

    Science.gov (United States)

    Volckens, J; Quinn, C; Leith, D; Mehaffy, J; Henry, C S; Miller-Lionberg, D

    2017-03-01

    Assessing personal exposure to air pollution has long proven challenging due to technological limitations posed by the samplers themselves. Historically, wearable aerosol monitors have proven to be expensive, noisy, and burdensome. The objective of this work was to develop a new type of wearable monitor, an ultrasonic personal aerosol sampler (UPAS), to overcome many of the technological limitations in personal exposure assessment. The UPAS is a time-integrated monitor that features a novel micropump that is virtually silent during operation. A suite of onboard environmental sensors integrated with this pump measure and record mass airflow (0.5-3.0 L/min, accurate within 5%), temperature, pressure, relative humidity, light intensity, and acceleration. Rapid development of the UPAS was made possible through recent advances in low-cost electronics, open-source programming platforms, and additive manufacturing for rapid prototyping. Interchangeable cyclone inlets provided a close match to the EPA PM 2.5 mass criterion (within 5%) for device flows at either 1.0 or 2.0 L/min. Battery life varied from 23 to 45 hours depending on sample flow rate and selected filter media. Laboratory tests of the UPAS prototype demonstrate excellent agreement with equivalent federal reference method samplers for gravimetric analysis of PM 2.5 across a broad range of concentrations. © 2016 The Authors. Indoor Air published by John Wiley & Sons Ltd.

  11. A Bayesian Sampler for Optimization of Protein Domain Hierarchies

    Science.gov (United States)

    2014-01-01

    Abstract The process of identifying and modeling functionally divergent subgroups for a specific protein domain class and arranging these subgroups hierarchically has, thus far, largely been done via manual curation. How to accomplish this automatically and optimally is an unsolved statistical and algorithmic problem that is addressed here via Markov chain Monte Carlo sampling. Taking as input a (typically very large) multiple-sequence alignment, the sampler creates and optimizes a hierarchy by adding and deleting leaf nodes, by moving nodes and subtrees up and down the hierarchy, by inserting or deleting internal nodes, and by redefining the sequences and conserved patterns associated with each node. All such operations are based on a probability distribution that models the conserved and divergent patterns defining each subgroup. When we view these patterns as sequence determinants of protein function, each node or subtree in such a hierarchy corresponds to a subgroup of sequences with similar biological properties. The sampler can be applied either de novo or to an existing hierarchy. When applied to 60 protein domains from multiple starting points in this way, it converged on similar solutions with nearly identical log-likelihood ratio scores, suggesting that it typically finds the optimal peak in the posterior probability distribution. Similarities and differences between independently generated, nearly optimal hierarchies for a given domain help distinguish robust from statistically uncertain features. Thus, a future application of the sampler is to provide confidence measures for various features of a domain hierarchy. PMID:24494927

  12. Partitioning of organochlorine pesticides from water to polyethylene passive samplers

    International Nuclear Information System (INIS)

    Hale, Sarah E.; Martin, Timothy J.; Goss, Kai-Uwe; Arp, Hans Peter H.; Werner, David

    2010-01-01

    The mass transfer rates and equilibrium partitioning behaviour of 14 diverse organochlorine pesticides (OCP) between water and polyethylene (PE) passive samplers, cut from custom made PE sheets and commercial polyethylene plastic bags, were quantified. Overall mass transfer coefficients, k O , estimated PE membrane diffusion coefficients, D PE , and PE-water partitioning coefficients, K PE-water, are reported. In addition, the partitioning of three polycyclic aromatic hydrocarbons (PAHs) from water to PE is quantified and compared with literature values. K PE-water values agreed mostly within a factor of two for both passive samplers and also with literature values for the reference PAHs. As PE is expected to exhibit similar sorption behaviour to long-chain alkanes, PE-water partitioning coefficients were compared to hexadecane-water partitioning coefficients estimated with the SPARC online calculator, COSMOtherm and a polyparameter linear free energy relationship based on the Abraham approach. The best correlation for all compounds tested was with COSMOtherm estimated hexadecane-water partitioning coefficients. - The partitioning of organochlorine pesticides between single phase polyethylene passive samplers and water is quantified.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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 microm 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 microm 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

  15. Performances of an atmospheric tritium sampler and its application

    International Nuclear Information System (INIS)

    Inoue, Yoshikazu; Kahn, B.; Carter, M.W.

    1983-01-01

    A sampling system for atmospheric tritium in the form of water vapor, hydrogen and hydrocarbons was designed and built. The air was passed first through molecular sieve which adsorbed water vapor, then over palladium catalyst which oxidized hydrogen and adsorbed resulting water in situ, and finally over hot Hopcalite catalyst, which oxidized hydrocarbons and the resulting water was adsorbed on a following molecular sieve column. Three water samples were extracted from adsorbers and their tritium contents were measured by liquid scintillation counting. Performances of this sampler were examined for retrieval of tritiated water from molecular sieve, oxidation of hydrogen on palladium catalyst and oxidation of methane on Hopcalite. The portable sampler was applied to analyze tritium in a duct air of a heavy water moderated research reactor. More than 99% of total tritium was in vapor form. Trace amounts of tritiated hydrogen and hydrocarbon were also detected. This tritium sampler is applicable to detect all of atmospheric tritium as high as ten times of ambient levels. (author)

  16. Real-time measurement of dust in the workplace using video exposure monitoring: Farming to pharmaceuticals

    International Nuclear Information System (INIS)

    Walsh, P T; Forth, A R; Clark, R D R; Dowker, K P; Thorpe, A

    2009-01-01

    Real-time, photometric, portable dust monitors have been employed for video exposure monitoring (VEM) to measure and highlight dust levels generated by work activities, illustrate dust control techniques, and demonstrate good practice. Two workplaces, presenting different challenges for measurement, were used to illustrate the capabilities of VEM: (a) poultry farming activities and (b) powder transfer operations in a pharmaceutical company. For the poultry farm work, the real-time monitors were calibrated with respect to the respirable and inhalable dust concentrations using cyclone and IOM reference samplers respectively. Different rankings of exposure for typical activities were found on the small farm studied here compared to previous exposure measurements at larger poultry farms: these were mainly attributed to the different scales of operation. Large variations in the ratios of respirable, inhalable and real-time monitor TWA concentrations of poultry farm dust for various activities were found. This has implications for the calibration of light-scattering dust monitors with respect to inhalable dust concentration. In the pharmaceutical application, the effectiveness of a curtain barrier for dust control when dispensing powder in a downflow booth was rapidly demonstrated.

  17. Investigations of Wind/WAVES Dust Impacts

    Science.gov (United States)

    St Cyr, O. C.; Wilson, L. B., III; Rockcliffe, K.; Mills, A.; Nieves-Chinchilla, T.; Adrian, M. L.; Malaspina, D.

    2017-12-01

    lifetime. We found a statistically significant and consistent trend of count rate deficits during the ICMEs compared to the periods immediately before and after the ICMEs. These preliminary results suggest that ICMEs may scatter micron-sized dust, or that they may exclude it during their initiation.

  18. The Lunar Dust Environment

    Science.gov (United States)

    Szalay, Jamey Robert

    Planetary bodies throughout the solar system are continually bombarded by dust particles, largely originating from cometary activities and asteroidal collisions. Surfaces of bodies with thick atmospheres, such as Venus, Earth, Mars and Titan are mostly protected from incoming dust impacts as these particles ablate in their atmospheres as 'shooting stars'. However, the majority of bodies in the solar system have no appreciable atmosphere and their surfaces are directly exposed to the flux of high speed dust grains. Impacts onto solid surfaces in space generate charged and neutral gas clouds, as well as solid secondary ejecta dust particles. Gravitationally bound ejecta clouds forming dust exospheres were recognized by in situ dust instruments around the icy moons of Jupiter and Saturn, and had not yet been observed near bodies with refractory regolith surfaces before NASA's Lunar Dust and Environment Explorer (LADEE) mission. In this thesis, we first present the measurements taken by the Lunar Dust Explorer (LDEX), aboard LADEE, which discovered a permanently present, asymmetric dust cloud surrounding the Moon. The global characteristics of the lunar dust cloud are discussed as a function of a variety of variables such as altitude, solar longitude, local time, and lunar phase. These results are compared with models for lunar dust cloud generation. Second, we present an analysis of the groupings of impacts measured by LDEX, which represent detections of dense ejecta plumes above the lunar surface. These measurements are put in the context of understanding the response of the lunar surface to meteoroid bombardment and how to use other airless bodies in the solar system as detectors for their local meteoroid environment. Third, we present the first in-situ dust measurements taken over the lunar sunrise terminator. Having found no excess of small grains in this region, we discuss its implications for the putative population of electrostatically lofted dust.

  19. Comparison of the sampling rates and partitioning behaviour of polar and non-polar contaminants in the polar organic chemical integrative sampler and a monophasic mixed polymer sampler for application as an equilibrium passive sampler.

    Science.gov (United States)

    Jeong, Yoonah; Schäffer, Andreas; Smith, Kilian

    2018-06-15

    In this work, Oasis HLB® beads were embedded in a silicone matrix to make a single phase passive sampler with a higher affinity for polar and ionisable compounds than silicone alone. The applicability of this mixed polymer sampler (MPS) was investigated for 34 aquatic contaminants (log K OW -0.03 to 6.26) in batch experiments. The influence of flow was investigated by comparing uptake under static and stirred conditions. The sampler characteristics of the MPS was assessed in terms of sampling rates (R S ) and sampler-water partition coefficients (K SW ), and these were compared to those of the polar organic chemical integrative sampler (POCIS) as a reference kinetic passive sampler. The MPS was characterized as an equilibrium sampler for both polar and non-polar compounds, with faster uptake rates and a shorter time to reach equilibrium than the POCIS. Water flow rate impacted sampling rates by up to a factor of 12 when comparing static and stirred conditions. In addition, the relative accumulation of compounds in the polyethersulfone (PES) membranes versus the inner Oasis HLB sorbent was compared for the POCIS, and ranged from <1% to 83% depending on the analyte properties. This is indicative of a potentially significant lag-phase for less polar compounds within POCIS. The findings of this study can be used to quantitatively describe the partitioning and kinetic behaviour of MPS and POCIS for a range of aquatic organic contaminants for application in field sampling. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Maintaining the Background Dust Opacity During Northern Hemisphere Summer Mars Using Wind Stress Based Dust Lifting

    Science.gov (United States)

    Jha, V.; Kahre, M. A.

    2017-12-01

    The Mars atmosphere has low levels of dust during Northern Hemisphere (NH) spring and summer (the non-dusty season) and increased levels during NH autumn and winter (the dusty season). In the absence of regional or global storms, dust devils and local storms maintain a background minimum dust loading during the non-dusty season. While observational surveys and Global Climate Model (GCM) studies suggest that dust devils are likely to be major contributors to the background haze during NH spring and summer, a complete understanding of the relative contribution of dust devils and local dust storms has not yet been achieved. We present preliminary results from an investigation that focuses on the effects of radiatively active water ice clouds on dust lifting processes during these seasons. Water ice clouds are known to affect atmospheric temperatures directly by absorption and emission of thermal infrared radiation and indirectly through dynamical feedbacks. Our goal is to understand how clouds affect the contribution by local (wind stress) dust storms to the background dust haze during NH spring and summer. The primary tool for this work is the NASA Ames Mars GCM, which contains physical parameterizations for a fully interactive dust cycle. Three simulations that included wind stress dust lifting were executed for a period of 5 Martian years: a case that included no cloud formation, a case that included radiatively inert cloud formation and a case that included radiatively active cloud (RAC) formation. Results show that when radiatively active clouds are included, the clouds in the aphelion cloud belt radiatively heat the atmosphere aloft in the tropics (Figure 1). This heating produces a stronger overturning circulation, which in turn produces an enhanced low-level flow in the Hadley cell return branch. The stronger low-level flow drives higher surface stresses and increased dust lifting in those locations. We examine how realistic these simulated results are by

  1. Summary report on the design of the retained gas sampler system (retained gas sampler, extruder and extractor)

    International Nuclear Information System (INIS)

    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.

    1994-01-01

    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 boundclose 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

  2. Combustible dusts: a serious industrial hazard.

    Science.gov (United States)

    Joseph, Giby

    2007-04-11

    After investigating three fatal explosions in manufacturing plants, the U.S. Chemical Safety and Hazard Investigation Board (CSB) has concluded: The explosive hazard of combustible dust is not well known, and helping industry to understand this hazard is a priority. Prompted by these three incidents in North Carolina, Kentucky and Indiana and the need to increase the hazard awareness, CSB is conducting a study to examine the nature and scope of dust explosion risks in industry and to identify initiatives that may be necessary to more effectively prevent combustible dust fires and explosions. Such initiatives may include regulatory action, voluntary consensus standards, or other measures that could be taken by industry, labor, government, and other parties. A critical task of the dust study is analyzing past incidents to determine the severity of the problem within industry. The analysis is focusing on the number of incidents, injuries and fatalities, industrial sectors affected, and regulatory oversight. This paper presents the preliminary findings from CSBs analysis of combustible dust incidents over the past 25 years. This paper has not been approved by the Board and is published for general informational purposes only. Every effort has been made to accurately present the contents of any Board-approved report mentioned in this paper. Any material in the paper that did not originate in a Board-approved report is solely the responsibility of the authors and does not represent an official finding, conclusion, or position of the Board.

  3. Dust Devil Tracks

    Science.gov (United States)

    2002-01-01

    (Released 8 May 2002) The Science This image, centered near 50.0 S and 17.7 W displays dust devil tracks on the surface. Most of the lighter portions of the image likely have a thin veneer of dust settled on the surface. As a dust devil passes over the surface, it acts as a vacuum and picks up the dust, leaving the darker substrate exposed. In this image there is a general trend of many of the tracks running from east to west or west to east, indicating the general wind direction. There is often no general trend present in dust devil tracks seen in other images. The track patterns are quite ephemeral and can completely change or even disappear over the course of a few months. Dust devils are one of the mechanisms that Mars uses to constantly pump dust into the ubiquitously dusty atmosphere. This atmospheric dust is one of the main driving forces of the present Martian climate. The Story Vrrrrooooooooom. Think of a tornado, the cartoon Tasmanian devil, or any number of vacuum commercials that powerfully suck up swirls of dust and dirt. That's pretty much what it's like on the surface of Mars a lot of the time. Whirlpools of wind called

  4. Analysis of "Midnight" Tracks in the Stardust Interstellar Dust Collector: Possible Discovery of a Contemporary Interstellar Dust Grain

    Science.gov (United States)

    Westphal, A. J.; Allen, C.; Bajit, S.; Bastien, R.; Bechtel, H.; Bleuet, P.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; hide

    2010-01-01

    In January 2006, the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, Comet 81P/Wild2, and a collector dedicated to the capture and return of contemporary interstellar dust. Both collectors were approximately 0.1m(exp 2) in area and were composed of aerogel tiles (85% of the collecting area) and aluminum foils. The Stardust Interstellar Dust Collector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 m(exp 2) day. The Stardust Interstellar Preliminary Examination (ISPE) is a three-year effort to characterize the collection using nondestructive techniques.

  5. Assessment of respirable dust and its free silica contents in different Indian coalmines.

    Science.gov (United States)

    Mukherjee, Ashit K; Bhattacharya, Sanat K; Saiyed, Habibullah N

    2005-04-01

    Assessment of respirable dust, personal exposures of miners and free silica contents in dust were undertaken to find out the associated risk of coal workers' pneumoconiosis in 9 coal mines of Eastern India during 1988-91. Mine Research Establishment (MRE), 113A Gravimetric Dust Sampler (GDS) and personal samplers (AFC 123), Cassella, London, approved by Director General of Mines Safety (DGMS) were used respectively for monitoring of mine air dust and personal exposures of miners. Fourier Transform Infra-red (FTIR) Spectroscopy determined free silica in respirable dusts. Thermal Conditions like Wet Bulb Globe Temperature (WBGT) index, humidity and wind velocity were also recorded during monitoring. The dust levels in the face return air of both, Board & Pillar (B&P) and Long Wall (LW) mining were found above the permissible level recommended by DGMS, Govt. of India. The drilling, blasting and loading are the major dusty operations in B&P method. Exposures of driller and loader were varied between, 0.81-9.48 mg/m3 and 0.05-9.84 mg/m3 respectively in B&P mining, whereas exposures of DOSCO loader, Shearer operator and Power Support Face Worker were varied between 2.65-9.11 mg/m3, 0.22-10.00 mg/m3 and 0.12-9.32 mg/m3 respectively in LW mining. In open cast mining, compressor and driller operators are the major exposed groups. The percentage silica in respirable dusts found below 5% in all most all the workers except among query loaders and drillers of open cast mines.

  6. [Assessment of occupational exposure to wood dust in the Polish furniture industry].

    Science.gov (United States)

    Szewczyńska, Małgorzata; Pośniak, Małgorzata

    2017-02-28

    Occupational exposure to wood dust can be responsible for many different harmful health effects, especially in workers employed in the wood industry. The assessment of wood dust adverse effects to humans, as well as the interpretation of its concentration measurements carried out to assess potential occupational exposure are very difficult. First of all, it is due to possible occurrence of different kind of wood dust in the workplace air, namely wood dust from dozens of species of trees belonging to 2 kinds of botanical gymnosperms and angiosperms, as well as to its different chemical composition. Total dust and respirable wood dust in the workplace air in the furniture industry was determined using the filtration-gravimetric method in accordance with Polish Standards PN-Z-04030-05:1991 and PN-Z-04030-06:1991. Air samples were collected based on the principles of individual dosimetry. Total dust concentrations were 0.84-13.92 mg/m3 and inhalable fraction concentrations, obtained after the conversion of total dust by applying a conversion factor of 1.59, were 1.34-22.13 mg/m3. Respirable fraction concentrations were 0.38-4.04 mg/m3, which makes approx. 25% of the inhalable fraction on average. The highest concentrations occurred in grinding and the lowest during milling processes of materials used in the manufacture of furniture. The results indicate that the share of respirable fraction in the inhalable fraction of wood dust is considerable. Due to the determination of the threshold limit value (TLV) for the inhalable fraction of wood dust, it is necessary to replace the previously used samplers for total dust with samplers that provide quantitative separation of wood dust inhalable fractions in accordance with the convention of this fraction as defined in PN-EN 481:1998. Med Pr 2017;68(1):45-60. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  7. Development of automatic smear testing sampler for radioactive contamination of floor in nuclear power plant

    International Nuclear Information System (INIS)

    Nozawa, Katsuro; Hashimoto, Hiroshi; Shinohara, Yohtaro; Iwaki, Kiyotaka

    1980-01-01

    The floor contamination with radioactive substances in the controlled area of nuclear power stations is strictly controlled, and it is tested by the smear method, wiping the contaminants on floors with filter papers or cloths and measuring the radioactive intensity to obtain contamination density. The works are very laborious, therefore the automatic smear sampler was developed. Simple operation, shortening of time required for wiping, constant and high efficiency of wiping, and easy numbering of samples were the aims in the development. The method of wiping, the mechanisms of wiping, cloth feeding and running, the surface pressure at the time of wiping, the number of times of wiping and required motor torque were studied. The outline of the developed sampler is explained. The performance of the sampler was compared with manual wiping. The efficiency of wiping with the sampler was 92%, assuming manual wiping as 100. Difference was not observed between careful manual wiping and the wiping with the sampler, therefore it was confirmed that this automatic floor smear sampler can be put in practical use. By conventional manual sampling, the maximum limit was about 400 samples/man-day, but when this sampler is used, about 1000 samples/sampler-day is possible. At present, this sampler is operated in Hamaoka Nuclear Power Station. (Kako, I.)

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

    Science.gov (United States)

    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.

  9. Comparison of PM collection efficiency of Gent and Airmatrics MiniVol portable air sampler

    International Nuclear Information System (INIS)

    Begum, Bilkis A.; Biswas, Swapan K.

    2005-01-01

    Gent PM sampler was developed as an integral part of several International Atomic Energy Agency sponsored coordinated research programmes (CRP) for collecting air particulate samples. On the other hand, the MiniVol Portable Air Sampler is a commercial ambient air sampler for particulate matter and non-reactive gases used by different agencies. Air quality management system requires comparable air quality data to be collected by different stake holders for assessment and regulatory purposes. In order to compare the characteristics of Gent sampler with the MiniVol Portable Air Sampler, the reproducibility of the sample mass collection efficiency were examined and the measured mass concentrations were compared. It was found that in case of PM 10 both samplers collect almost same fraction of PM 10 mass when the Gent sampler was operated at 16 litre per minute flow rate. But in case of fine fraction, Portable sampler collects 70% higher PM 2.5 mass concentration compared to the Gent PM 2.2 mass concentrations. This is because, the Gent sampler was typically operated at 16 to 17 lpm resulting in an estimated 50% cut point of 2.2 μm.(author)

  10. Whither Cometary Dust?

    Science.gov (United States)

    Lisse, Carey M.

    2010-10-01

    In this paper I will discuss recent findings that have important implications for our understanding of the formation and evolution of primitive solar system dust, including: - Nesvorny et al. (2010), following up on their dynamical analyses of the zodiacal dust bands as sourced by the breakup of the Karin (5Mya) and Veritas (8Mya) asteroid families, argue that over 90% of the interplanetary dust cloud at 1 AU comes from JFC comets with near-circularized, low inclination orbits. This implies that the noted IPD collections of anhydrous and hydrous dust particles are likely to be from Oort cloud and JFC comets, respectively, not from asteroids and comets as thought in the past. Hydrous dust particles from comets like 85P/Wild2 and 9P/Tempel 1 would be consistent with results from the STARDUST and Deep Impact experiments. - Estimates of the dust particle size distributions (PSDs) in the comae of 85P/Wild2 (Green et al. 2004, 2007) and 73P/SW-3 (Sitko et al. 2010, Vaubaillon & Reach 2010) and in the trails of comets (Reach et al. 2007) have broken power law structure, with a plateau enhancement of particles of 1 mm - 1 cm in size. This size is also the size of most chondritic inclusions, and the predicted size range of the "aggregational barrier", where collisions between dust particles become destructive. - Studies of the albedo and polarization properties of cometary dust (Kolokolova et al. 2007) suggest there are 2 major groupings, one with low scattering capability and one with high. While these families could possibly have been explained by systematics in the PSDs of the emitted dust, independent work by Lisse et al. (2008) on the mineralogy of a number of highly dusty comets has shown evidence for one family of comets with highly crystalline dust and another with highly amorphous dust.

  11. Communication plan for windblown dust.

    Science.gov (United States)

    2015-05-01

    Windblown dust events occur in Arizona, and blowing dust has been considered a contributing factor to serious crashes on the : segment of Interstate 10 (I10) between Phoenix and Tucson, as well as on other Arizona roadways. Arizonas dust events...

  12. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Mathis, J.S.

    1978-01-01

    The author's review concentrates on theoretical aspects of dust in planetary nebulae (PN). He considers the questions: how much dust is there is PN; what is its composition; what effects does it have on the ionization structure, on the dynamics of the nebula. (Auth.)

  13. Toxicity of lunar dust

    NARCIS (Netherlands)

    Linnarsson, D.; Carpenter, J.; Fubini, B.; Gerde, P.; Loftus, D.; Prisk, K.; Staufer, U.; Tranfield, E.; van Westrenen, W.

    2012-01-01

    The formation, composition and physical properties of lunar dust are incompletely characterised with regard to human health. While the physical and chemical determinants of dust toxicity for materials such as asbestos, quartz, volcanic ashes and urban particulate matter have been the focus of

  14. Combustible dust tests

    Science.gov (United States)

    The sugar dust explosion in Georgia on February 7, 2008 killed 14 workers and injured many others (OSHA, 2009). As a consequence of this explosion, OSHA revised its Combustible Dust National Emphasis (NEP) program. The NEP targets 64 industries with more than 1,000 inspections and has found more tha...

  15. Evaluation of Dust Exposure among the Workers in Agricultural Industries in North-East India.

    Science.gov (United States)

    Dewangan, Krishna N; Patil, Mahesh R

    2015-11-01

    This study aims to quantify dust exposure among the workers in four different industrial settings: rice mills, flour mills, oil mills, and tea factories and to compare the obtained data with the permissible exposure limit (PEL) of Indian Union Ministry of Labour as well as to compare the dust exposure across activities and seasons. RespiCon(TM) particle sampler was used for collecting dust concentration in the breathing zone of the workers. In total, 149 workers participated in the study and 204 samples were collected. Samples were collected in the vicinity of different processing operations. Samples in the rice mills were collected for two consecutive years in two seasons; however samples from other industries were collected for 1 year. The results indicate that geometric mean (GM) of dust exposure was significantly (P workers are exposed to higher level of respirable dust as compared to the PEL, while total dust exposure to all the workers were higher than the PEL; thus, immediate reduction of dust exposure among the workers is necessary for preventing respiratory system impairment. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  16. FAST MUSIC SPECTRUM PEAK SEARCH VIA METROPOLIS-HASTINGS SAMPLER

    Institute of Scientific and Technical Information of China (English)

    Guo Qinghua; Liao Guisheng

    2005-01-01

    A fast MUltiple SIgnal Classification (MUSIC) spectrum peak search algorithm is devised, which regards the power of the MUSIC spectrum function as target distribution up to a constant of proportionality, and uses Metropolis-Hastings (MH) sampler, one of the most popular Markov Chain Monte Carlo (MCMC) techniques, to sample from it. The proposed method reduces greatly the tremendous computation and storage costs in conventional MUSIC techniques i.e., about two and four orders of magnitude in computation and storage costs under the conditions of the experiment in the paper respectively.

  17. Soil separator and sampler and method of sampling

    Science.gov (United States)

    O'Brien, Barry H [Idaho Falls, ID; Ritter, Paul D [Idaho Falls, ID

    2010-02-16

    A soil sampler includes a fluidized bed for receiving a soil sample. The fluidized bed may be in communication with a vacuum for drawing air through the fluidized bed and suspending particulate matter of the soil sample in the air. In a method of sampling, the air may be drawn across a filter, separating the particulate matter. Optionally, a baffle or a cyclone may be included within the fluidized bed for disentrainment, or dedusting, so only the finest particulate matter, including asbestos, will be trapped on the filter. The filter may be removable, and may be tested to determine the content of asbestos and other hazardous particulate matter in the soil sample.

  18. Respirable dust measured downwind during rock dust application.

    Science.gov (United States)

    Harris, M L; Organiscak, J; Klima, S; Perera, I E

    2017-05-01

    The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

  19. Lunar Dust Mitigation Screens

    Science.gov (United States)

    Knutson, Shawn; Holloway, Nancy

    With plans for the United States to return to the moon, and establish a sustainable human presence on the lunar surface many issues must be successfully overcome. Lunar dust is one of a number of issues with the potential to create a myriad of problems if not adequately addressed. Samples of dust brought back from Apollo missions show it to be soft, yet sharp and abrasive. The dust consists of a variety of morphologies including spherical, angular blocks, shards, and a number of irregular shapes. One of the main issues with lunar dust is its attraction to stick to anything it comes in contact with (i.e. astronauts, equipment, habitats, etc.). Ionized radiation from the sun strikes the moon's surface and creates an electrostatic charge on the dust. Further, the dust harbors van der Waals forces making it especially difficult to separate once it sticks to a surface. During the Apollo missions, it was discovered that trying to brush the lunar dust from spacesuits was not effective, and rubbing it caused degradation of the suit material. Further, when entering the lunar module after moonwalks, the astronauts noted that the dust was so prolific inside the cabin that they inhaled and ingested it, causing at least one of them, Harrison "Jack" Schmidt, to report irritation of the throat and lungs. It is speculated that the dust could also harm an astronaut's nervous and cardiovascular systems, especially during an extended stay. In addition to health issues, the dust can also cause problems by scouring reflective coatings off of thermal blankets, and roughening surfaces of windows and optics. Further, panels on solar cells and photovoltaics can also be compromised due to dust sticking on the surfaces. Lunar dust has the capacity to penetrate seals, interfere with connectors, as well as mechanisms on digging machines, all of which can lead to problems and failure. To address lunar dust issues, development of electrostatic screens to mitigate dust on sur-faces is currently

  20. Agglomeration of dust in convective clouds initialized by nuclear bursts

    Science.gov (United States)

    Bacon, D. P.; Sarma, R. A.

    Convective clouds initialized by nuclear bursts are modeled using a two-dimensional axisymmetric cloud model. Dust transport through the atmosphere is studied using five different sizes ranging from 1 to 10,000 μm in diameter. Dust is transported in the model domain by advection and sedimentation. Water is allowed to condense onto dust particles in regions of supersaturation in the cloud. The agglomeration of dust particles resulting from the collision of different size dust particles is modeled. The evolution of the dust mass spectrum due to agglomeration is modeled using a numerical scheme which is mass conserving and has low implicit diffusion. Agglomeration moves mass from the small particles with very small fall velocity to the larger sizes which fall to the ground more readily. Results indicate that the dust fallout can be increased significantly due to this process. In preliminary runs using stable and unstable environmental soundings, at 30 min after detonation the total dust in the domain was 11 and 30%, respectively, less than a control case without agglomeration.

  1. Mobile dynamic passive sampling of trace organic compounds: Evaluation of sampler performance in the Danube River.

    Science.gov (United States)

    Vrana, Branislav; Smedes, Foppe; Allan, Ian; Rusina, Tatsiana; Okonski, Krzysztof; Hilscherová, Klára; Novák, Jiří; Tarábek, Peter; Slobodník, Jaroslav

    2018-03-29

    A "dynamic" passive sampling (DPS) device, consisting of an electrically driven large volume water pumping device coupled to a passive sampler exposure cell, was designed to enhance the sampling rate of trace organic compounds. The purpose of enhancing the sampling rate was to achieve sufficient method sensitivity, when the period available for sampling is limited to a few days. Because the uptake principle in the DPS remains the same as for conventionally-deployed passive samplers, free dissolved concentrations can be derived from the compound uptake using available passive sampler calibration parameters. This was confirmed by good agreement between aqueous concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) derived from DPS and conventional caged passive sampler. The DPS device enhanced sampling rates of compounds that are accumulated in samplers under water boundary layer control (WBL) more than five times compared with the conventionally deployed samplers. The DPS device was deployed from a ship cruising downstream the Danube River to provide temporally and spatially integrated concentrations. A DPS-deployed sampler with surface area of 400cm 2 can reach sampling rates up to 83Ld -1 . The comparison of three passive samplers made of different sorbents and co-deployed in the DPS device, namely silicone rubber (SR), low density polyethylene (LDPE) and SDB-RPS Empore™ disks showed a good correlation of surface specific uptake for compounds that were sampled integratively during the entire exposure period. This provided a good basis for a cross-calibration between the samplers. The good correlation of free dissolved PAHs, PCBs and HCB concentration estimates obtained using SR and LDPE confirmed that both samplers are suitable for the identification of concentration gradients and trends in the water column. We showed that the differences in calculated aqueous concentrations between sampler types

  2. Measurements of ambient radioxenon levels using the automated radioxenon sampler/analyzer (ARSA)

    International Nuclear Information System (INIS)

    McIntyre, J.I.; Abel, K.H.; Bowyer, T.W.; Hayes, J.C.; Heimbigner, T.R.; Panisko, M.E.; Reeder, P.L.; Thompson, R.C.

    2001-01-01

    The Pacific Northwest National Laboratory has developed an Automated Radioxenon Sampler/Analyzer (ARSA) in support of the Comprehensive Nuclear-Test-Ban-Treaty (CTBT) to measure four radioxenon isotopes: 131m Xe, 133m Xe, 133g Xe, and 135g Xe. This system uses a beta-gamma coincidence counting detector to produce two-dimensional plots of gamma-energy versus beta-energy. Betas and conversion electrons (CE) are detected in a cylindrical plastic scintillation cell and gamma and X-rays are detected in a surrounding NaI(Tl) scintillation detector. The ARSA has been field tested at several locations to measure the radioxenon concentrations. Most recently it has been deployed at the Institut fuer Atmosphaerische Radioaktivitaet in Freiburg, Germany. During the first 4 months of 2000 the measured 133 Xe concentrations have varied between 0.0 ± 0.1 and 110 ± 10 mBq/m 3 air. The longer lived 131m Xe (T 1/2 = 11.9 d) and short lived 135 Xe (T 1/2 = 9.1 h) have also been detected in small quantities, while 133m Xe concentrations have been consistent with zero. Minimum detectable concentration (MDC) calculations for 133g Xe fell well below the 1 mBq per standard-cubic-meter of air requirement adopted by the CTBT Preparatory Commission. A description of the radioxenon detector, the concentration and MDC calculations and preliminary results of the field test in Germany are presented. (author)

  3. Visual Chronicles from the Balkans and Central Europe: Samplers Remembered

    Directory of Open Access Journals (Sweden)

    Maria-Alina Asavei

    2016-03-01

    Full Text Available This paper examines the relationship between craft and popular culture by focusing on a peculiar type of textile sampler (needlework that used to be omnipresent in the last century both in rural and urban houses across Central and South-Eastern Europe. Although these hand-crafted items are no longer part of today’s ‘compulsory’ household, they are still regarded as nostalgic, familiar or emotional forms of materiality and tangibility which perform a cultural politics of identity. These vernacular textiles predate the digital age and the free market and yet co-evolve and interact with digital networks and technologies. This paper brings into focus ‘amateur’ and regional forms of home grown cultural expression and the ways in which these forms of folk creativity and materiality are recast in contemporary urban popular culture and arts. Thus, the main aim of this study is to explore the contemporary re-enactments of these vernacular samplers.

  4. Responses of low pressure Andersen sampler for collecting substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, K. [Research Reactor Institute, Kyoto University, Osaka (Japan); Yamada, Y.; Miyamoto, K.; Shimo, M. [Division of Radiotoxicology and Protection, National Institute of Radiological Sciences, Chiba (Japan)

    2000-05-01

    Some types of low pressure cascade impactors (Andersen, Berner, Davies, and MOUDI etc) have been used to measure the activity size distribution of radon progeny in the environment. In spite of their careful uses, their nonideal responses are not adequately known. Some important factors such as the wall loss, electrostatic attraction, and the surface nature of collecting substrates may affect the reliability of the impactor data. Size selective characteristics of a low pressure Andersen sampler for various collecting substrates were examined in a radon exposure chamber using several kinds of liquid (DOS) or solid (carnauba wax) carrier aerosols labelled with radon progeny. These carrier aerosols were produced by commercial condensation aerosol generator. Tested collecting substrates were, (1) uncoated clean stainless steel plate, (2) silicone oil or grease coated stainless steel plate, (3) polyethylene sheet covered stainless steel plate, (4) membrane filter, (5) glass fiber filter, and (6) quartz fiber filter. In the case of collecting liquid or sticky carrier aerosols, the effect of particle bounce was small and nearly any substrates might used on the impaction plate. On the other hand, in the case of solid carrier aerosols, an adhesive layer such as grease or oil might have to be applied to the substrate. It was concluded that a low pressure cascade impactor such as Andersen sampler might need an appropriate calibration procedure including the interstage characteristics for determining the accurate activity size distribution. (author)

  5. Hayabusa2 Sampler: Collection of Asteroidal Surface Material

    Science.gov (United States)

    Sawada, Hirotaka; Okazaki, Ryuji; Tachibana, Shogo; Sakamoto, Kanako; Takano, Yoshinori; Okamoto, Chisato; Yano, Hajime; Miura, Yayoi; Abe, Masanao; Hasegawa, Sunao; Noguchi, Takaaki

    2017-07-01

    Japan Aerospace Exploration Agency (JAXA) launched the asteroid exploration probe "Hayabusa2" in December 3rd, 2014, following the 1st Hayabusa mission. With technological and scientific improvements from the Hayabusa probe, we plan to visit the C-type asteroid 162137 Ryugu (1999 JU3), and to sample surface materials of the C-type asteroid that is likely to be different from the S-type asteroid Itokawa and contain more pristine materials, including organic matter and/or hydrated minerals, than S-type asteroids. We developed the Hayabusa2 sampler to collect a minimum of 100 mg of surface samples including several mm-sized particles at three surface locations without any severe terrestrial contamination. The basic configuration of the sampler design is mainly as same as the 1st Hayabusa (Yano et al. in Science, 312(5778):1350-1353, 2006), with several minor but important modifications based on lessons learned from the Hayabusa to fulfill the scientific requirements and to raise the scientific value of the returned samples.

  6. Quantifying Anthropogenic Dust Emissions

    Science.gov (United States)

    Webb, Nicholas P.; Pierre, Caroline

    2018-02-01

    Anthropogenic land use and land cover change, including local environmental disturbances, moderate rates of wind-driven soil erosion and dust emission. These human-dust cycle interactions impact ecosystems and agricultural production, air quality, human health, biogeochemical cycles, and climate. While the impacts of land use activities and land management on aeolian processes can be profound, the interactions are often complex and assessments of anthropogenic dust loads at all scales remain highly uncertain. Here, we critically review the drivers of anthropogenic dust emission and current evaluation approaches. We then identify and describe opportunities to: (1) develop new conceptual frameworks and interdisciplinary approaches that draw on ecological state-and-transition models to improve the accuracy and relevance of assessments of anthropogenic dust emissions; (2) improve model fidelity and capacity for change detection to quantify anthropogenic impacts on aeolian processes; and (3) enhance field research and monitoring networks to support dust model applications to evaluate the impacts of disturbance processes on local to global-scale wind erosion and dust emissions.

  7. Effects of Hardness on Pintle Rod Performance in the Universal and Retained Gas Samplers

    International Nuclear Information System (INIS)

    BOGER, R.M.

    1999-01-01

    Interaction between hardness of the pintle rods and the retainer rings used in the core samplers is investigated. It is found that ordinary Rockwell C measurements are not sufficient and superficial hardness instruments are recommended to verify hardness since in-production hardness of pintle rods is found to vary widely and probably leads to some premature release of pistons in samplers

  8. 40 CFR 53.54 - Test for proper sampler operation following power interruptions.

    Science.gov (United States)

    2010-07-01

    ...) Mean sample flow rate. (i) From the certified measurements (Qref) of the test sampler flow rate... facilitate measurement of sample flow rate at the sampler downtube. (5) Means for creating an additional... pressures and temperatures used in the tests and shall be checked at zero and at least one flow rate within...

  9. Chemistry of the sea surface microlayer. 1. Fabrication and testing of the sampler

    Digital Repository Service at National Institute of Oceanography (India)

    Singbal, S.Y.S.; Narvekar, P.V.

    A screen sampler fabricated to study the sea surface microlayer (SML) has been described. The screen sampler was tested in the Mandovi estuary and adjacent waters. Physico-chemical parameters of the subsurface waters from a depth of 25 cm was also...

  10. Performance Evaluation of Automated Passive Capillary Sampler for Estimating Water Drainage in the Vadose Zone

    Science.gov (United States)

    Passive capillary samplers (PCAPs) are widely used to monitor, measure and sample drainage water under saturated and unsaturated soil conditions in the vadose zone. The objective of this study was to evaluate the performance and accuracy of automated passive capillary sampler for estimating drainage...

  11. Evaluating the Relationship between Equilibrium Passive Sampler Uptake and Aquatic Organism Bioaccumulation (IPSW)

    Science.gov (United States)

    This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) as it relates to organism bioaccumulation in the water column and interstitial water. Fifty-five studies were found where both passive samplers and organism bioaccumulation were used to measur...

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

    Science.gov (United States)

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

    2018-04-01

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

  13. A cheap and simple passive sampler using silicone rubber for the ...

    African Journals Online (AJOL)

    caffeine, personal care products, pharmaceuticals, pesticides and polycyclic aromatic hydrocarbons. Keywords: passive sampler, silicone rubber (PDMS) tubing, GCxGC-TOFMS, ..... concentrations may be derived by using performance reference compounds to determine in situ passive sampler sampling rates followed by ...

  14. Determination of organochlorine pesticides in Indian coastal water using a moored in-situ sampler

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.; SenGupta, R.

    An attempt has been made to determine the concentration of different organochlorine pesticides in the seawater off the central West Coast of India using an in-situ-sampler. The Seastar in-situ sampler is an instrument, which is designed to pump...

  15. The Mars Dust Cycle: Investigating the Effects of Radiatively Active Water Ice Clouds on Surface Stresses and Dust Lifting Potential with the NASA Ames Mars General Circulation Model

    Science.gov (United States)

    Kahre, Melinda A.; Hollingsworth, Jeffery

    2012-01-01

    The dust cycle is a critically important component of Mars' current climate system. Dust is present in the atmosphere of Mars year-round but the dust loading varies with season in a generally repeatable manner. Dust has a significant influence on the thermal structure of the atmosphere and thus greatly affects atmospheric circulation. The dust cycle is the most difficult of the three climate cycles (CO2, water, and dust) to model realistically with general circulation models. Until recently, numerical modeling investigations of the dust cycle have typically not included the effects of couplings to the water cycle through cloud formation. In the Martian atmosphere, dust particles likely provide the seed nuclei for heterogeneous nucleation of water ice clouds. As ice coats atmospheric dust grains, the newly formed cloud particles exhibit different physical and radiative characteristics. Thus, the coupling between the dust and water cycles likely affects the distributions of dust, water vapor and water ice, and thus atmospheric heating and cooling and the resulting circulations. We use the NASA Ames Mars GCM to investigate the effects of radiatively active water ice clouds on surface stress and the potential for dust lifting. The model includes a state-of-the-art water ice cloud microphysics package and a radiative transfer scheme that accounts for the radiative effects of CO2 gas, dust, and water ice clouds. We focus on simulations that are radiatively forced by a prescribed dust map, and we compare simulations that do and do not include radiatively active clouds. Preliminary results suggest that the magnitude and spatial patterns of surface stress (and thus dust lifting potential) are substantial influenced by the radiative effects of water ice clouds.

  16. Honey Bees (Apis mellifera, L.) as Active Samplers of Airborne Particulate Matter.

    Science.gov (United States)

    Negri, Ilaria; Mavris, Christian; Di Prisco, Gennaro; Caprio, Emilio; Pellecchia, Marco

    2015-01-01

    Honey bees (Apis mellifera L.) are bioindicators of environmental pollution levels. During their wide-ranging foraging activity, these hymenopterans are exposed to pollutants, thus becoming a useful tool to trace the environmental contaminants as heavy metals, pesticides, radionuclides and volatile organic compounds. In the present work we demonstrate that bees can also be used as active samplers of airborne particulate matter. Worker bees were collected from hives located in a polluted postmining area in South West Sardinia (Italy) that is also exposed to dust emissions from industrial plants. The area is included in an official list of sites of national interest for environmental remediation, and has been characterized for the effects of pollutants on the health of the resident population. The head, wings, hind legs and alimentary canal of the bees were investigated with Scanning Electron Microscopy coupled with X-ray spectroscopy (SEM-EDX). The analyses pointed to specific morphological and chemical features of the particulate, and resulted into the identification of three categories of particles: industry-, postmining-, and soil-derived. With the exception of the gut, all the analyzed body districts displayed inorganic particles, mostly concentrated in specific areas of the body (i.e. along the costal margin of the fore wings, the medial plane of the head, and the inner surface of the hind legs). The role of both past mining activities and the industrial activity close to the study area as sources of the particulate matter is also discussed. We conclude that honey bees are able to collect samples of the main airborne particles emitted from different sources, therefore could be an ideal tool for monitoring such a kind of pollutants.

  17. Using an Instrumented Drone to Probe Dust Devils on Oregon’s Alvord Desert

    Directory of Open Access Journals (Sweden)

    Brian Jackson

    2018-01-01

    Full Text Available Dust devils are low-pressure, small (many to tens of meters convective vortices powered by surface heating and rendered visible by lofted dust. Dust devils occur ubiquitously on Mars, where they may dominate the supply of atmospheric dust, and since dust contributes significantly to Mars’ atmospheric heat budget, dust devils probably play an important role in its climate. The dust-lifting capacity of a devil likely depends sensitively on its structure, particularly the wind and pressure profiles, but the exact dependencies are poorly constrained. Thus, the exact contribution to Mars’ atmosphere remains unresolved. Analog studies of terrestrial devils have provided some insights into dust devil dynamics and properties but have been limited to near-surface (few meters or relatively high altitude (hundreds of meters sampling. Automated aerial vehicles or drones, combined with miniature, digital instrumentation, promise a novel and uniquely powerful platform from which to sample dust devils at a wide variety of altitudes. In this article, we describe a pilot study using an instrumented quadcopter on an active field site in southeastern Oregon, which (to our knowledge has not previously been surveyed for dust devils. We present preliminary results from the encounters, including stereo image analysis and encounter footage collected onboard the drone. In spite of some technical difficulties, we show that a quadcopter can successfully navigate in an active dust devil, while collecting time-series data about the dust devil’s structure.

  18. Spirit Feels Dust Gust

    Science.gov (United States)

    2007-01-01

    On sol 1149 (March 28, 2007) of its mission, NASA's Mars Exploration Rover Spirit caught a wind gust with its navigation camera. A series of navigation camera images were strung together to create this movie. The front of the gust is observable because it was strong enough to lift up dust. From assessing the trajectory of this gust, the atmospheric science team concludes that it is possible that it passed over the rover. There was, however, no noticeable increase in power associated with this gust. In the past, dust devils and gusts have wiped the solar panels of dust, making it easier for the solar panels to absorb sunlight.

  19. Assembly, operation and disassembly manual for the Battelle Large Volume Water Sampler (BLVWS)

    International Nuclear Information System (INIS)

    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

  20. DUST AND INFRARED IMAGING OF POLAR RING GALAXIES

    NARCIS (Netherlands)

    ARNABOLDI, M; FREEMAN, KC; SACKETT, PD; SPARKE, LS; CAPACCIOLI, M

    1995-01-01

    We have derived surface photometry for a sample of five polar ring(PR) galaxies in the optical (B and R bands) and in the near-IR (K band). Our preliminary results show that the morphology of these objects is heavily perturbed by dust, which sometimes completely hides the real distribution of the

  1. Galactic dust and extinction

    International Nuclear Information System (INIS)

    Lyngaa, G.

    1979-01-01

    The ratio R between visual extinction and colour excess, is slightly larger than 3 and does not vary much throughout our part of the Galaxy. The distribution of dust in the galactic plane shows, on the large scale, a gradient with higher colour excesses towards l=50 0 than towards l=230 0 . On the smaller scale, much of the dust responsible for extinction is situated in clouds which tend to group together. The correlation between positions of interstellar dust clouds and positions of spiral tracers seems rather poor in our Galaxy. However, concentrated dark clouds as well as extended regions of dust show an inclined distribution similar to the Gould belt of bright stars. (Auth.)

  2. Battling coal and rock dust in mines. Bor'ba s ugol'noi i porodnoi pyl'yu v shakhtakh

    Energy Technology Data Exchange (ETDEWEB)

    Petrukhin, P.M.; Grodel, G.S.; Korenev, A.P.; Krivokhizha, B.M.; Kul' bachnyi, A.N.; Lyubimova, A.I.; Medvedev, E.N.; Yaremachenko, P.P.; Zhilyaev, N.I.

    1981-01-01

    The problems of comprehensive removal of dust from the atmosphere in mines are discussed. Physical and pnysicochemical properties of mine dust are described, which are important for estimating the processes of its formation, spread, and suppression. Presented are the results of theoretical and natural studies of dust aerodynamics of mines. Modern methods for battling coal and rock dust in mines, as well as means of monitoring the dust level of the air are outlined. Technical descriptions are given for new instruments for changing the dust level of the air. Brief reports are given on the preliminary wetting of coal in the massif, and theoretical and practical problems are discussed concerning hydrological methods of dust removal, dust suppression by foam, and dust trapping during the operation of mining equipment, and also on removal of dust from the air at the surface complex of a mine.

  3. Radioisotope dust pollution monitor

    International Nuclear Information System (INIS)

    Szepke, R.; Harasimczuk, J.; Dobrowiecki, J.

    1990-01-01

    Measuring principles and specification of two dust monitors: station-type AMIZ and portable-type PIK-10 for ambient air pollution are presented. The first one, a fully automatic instrument is destined for permanent monitoring of air pollution in preset sampling time from .25 to 24 hours. The second one was developed as a portable working model. Both instruments display their results in digital form in dust concentration units. (author)

  4. Coal dust symposium

    Energy Technology Data Exchange (ETDEWEB)

    1981-03-01

    This paper gives a report of the paper presented at the symposium held in Hanover on 9 and 10 February 1981. The topics include: the behaviour of dust and coal dust on combustion and explosion; a report on the accidents which occurred at the Laegerdorf cement works' coal crushing and drying plant; current safety requirements at coal crushing and drying plant; and coal crushing and drying. Four papers are individually abstracted. (In German)

  5. Dust devil generation

    International Nuclear Information System (INIS)

    G Onishchenko, O; A Pokhotelov, O; Horton, W; Stenflo, L

    2014-01-01

    The equations describing axi-symmetric nonlinear internal gravity waves in an unstable atmosphere are derived. A hydrodynamic model of a dust devil generation mechanism in such an atmosphere is investigated. It is shown that in an unstably stratified atmosphere the convective plumes with poloidal motion can grow exponentially. Furthermore, it is demonstrated that these convective plumes in an atmosphere with weak large scale toroidal motion are unstable with respect to three-dimensional dust devil generation. (papers)

  6. Using an Instrumented Drone to Sample Dust Devils

    Science.gov (United States)

    Jackson, Brian; Lorenz, Ralph; Davis, Karan; Lipple, Brock

    2017-10-01

    Dust devils are low-pressure, small (many to tens of meters) convective vortices powered by surface heating and rendered visible by lofted dust. Dust devils occur in arid climates on Earth, where they degrade air quality and pose a hazard to small aircraft. They also occur ubiquitously on Mars, where they may dominate the supply of atmospheric dust. Since dust contributes significantly to Mars’ atmospheric heat budget, dust devils probably play an important role in its climate. The dust-lifting capacity of a devil likely depends sensitively on its structure, particularly the wind and pressure profiles, but the exact dependencies are poorly constrained. Thus, the exact contribution to Mars’ atmosphere remains unresolved. Moreover, most previous studies of martian dust devils have relied on passive sampling of the profiles via meteorology packages on landed spacecraft, resulting in random encounter geometries which non-trivially skew the retrieved profiles. Analog studies of terrestrial devils have employed more active sampling (instrumented vehicles or manned aircraft) but have been limited to near-surface (few meters) or relatively high altitude (hundreds of meters) sampling. Unmanned aerial vehicles (UAVs) or drones, combined with miniature, digital instrumentation, promise a novel and uniquely powerful platform from which to sample dust devils via (relatively) controlled geometries at a wide variety of altitudes. In this presentation, we will describe a pilot study using an instrumented quadcopter on an active field site in southeastern Oregon, which (to our knowledge) has not previously been surveyed for dust devils. We will present preliminary results from the resulting encounters, including stereo image analysis and encounter footage collected onboard the drone.

  7. Determining the Influence of Dust on Post-Glacial Lacustrine Sedimentation in Bald Lake, Uinta Mountains, Utah

    Science.gov (United States)

    O'Keefe, S. S.; McElroy, R.; Munroe, J. S.

    2016-12-01

    Dust is increasingly recognized as an important component of biogeochemical cycling and ecosystem function in mountain environments. Previous work has shown that delivery of dust to the Uinta Mountains of northeastern Utah has influenced pedogenesis, soil nutrient status, and surface water chemistry. An array of passive and active samplers in the alpine zone of the Uintas provides detailed information about contemporary dust fluxes, along with physical and geochemical properties of modern dust. Reconstruction of changes in the dust system over time, however, requires continuous sedimentary archives sensitive to dust inputs. A radiocarbon-dated 3.5-m core (spanning 12.7 kyr) collected from subalpine Bald Lake may provide such a record. Passive dust collectors in the vicinity of the lake constrain the geochemical properties of modern dust, whereas samples of regolith constrain properties of the local surficial material within the watershed. Together, these represent two end member sources of clastic sediment to Bald Lake basin: allochthonous dust and autochthonous regolith. Ba and Eu are found in higher abundances in the dust than in the watershed regolith. Zr and Th are found to be lower in the dust than in the watershed. Geochemical analysis of the sediment core allows the relative contribution of exotic and local material to the lake to be considered as a time series covering the post-glacial interval when indicator elements are plotted. Findings suggest Bald Lake's dust record tracks regional aridity and corresponds to low-stands of large lakes in the southwestern United States. Spatial variability of elemental abundances in the watershed suggests there are more than two input sources contributing to the lake over time.

  8. Two-Stage Variable Sample-Rate Conversion System

    Science.gov (United States)

    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.

  9. Operating manual for Ford's Farm Range air samplers

    International Nuclear Information System (INIS)

    Glissmeyer, J.A.; Halverson, M.A.

    1980-10-01

    An air-sampling program was designed for a target enclosure at the Ford's Farm Range, Aberdeen Proving Ground, Maryland, where the Army test-fires tungsten and depleted-uranium armor penetrators. The primary potential particle inhalation hazard is depleted uranium. The sampling program includes workplace and filtered exhaust air sampling. Conventional isokinetic stack sampling was employed for the filtered exhaust air. Because of the need for rapid monitor response to concentration increases and decreases, conventional radioactive particle monitors were not used. Instead, real-time aerosol monitors employing a light-scattering technique were used for monitors requiring a fast response. For other monitoring functions, piezoelectric and beta-attenuation respirable-particle sampling techniques were used. The application of these technologies to the monitoring of airborne radioactive contaminants is addressed. Sampler installation and operation are detailed

  10. Concentrations of pollutants in fogwaters using a Grunow fogwater sampler

    Energy Technology Data Exchange (ETDEWEB)

    Schrimpff, E.; Klemm, O.; Eiden, R.; Frevert, T.; Herrmann, R.

    1984-02-01

    A simple device for sampling fog water is described (modified passive Grunow sampler), and analytical results as were found in rain and fog waters are reported. All samples were taken in the northern part of the Frankenwald mountains (near Bad Steben) from November 1982 until March 1983. Specific conductivity (..mu..Sxcm/sup -1/, 20/sup 0/C), titration acidity, Cl/sup -/, NO/sub 3//sup -/, SO/sub 4//sup 2 -/, total hardness, Ca, Na, Fe, Cd, Pb, TDOC and the polycyclic aromates fluoranthene and 3.4-benzopyrene were continuously higher in fog than in rain water. pH's were remarkably decreased in fog water. Here extreme results were measured in the first two weeks of March with pH 2.5, and acidities proportional2 mequivxl/sup -1/. Possible reasons for such extraordinary concentrations are discussed meteorologically as well as hydrochemically.

  11. Long-range Transported African Dust in the Caribbean Region: Dust Concentrations and Water-soluble Ions

    Science.gov (United States)

    Santos-Figueroa, G.; Avilés-Piñeiro, G. M.; Mayol-Bracero, O. L.

    2017-12-01

    Long-range transported African dust (LRTAD) particles reach the Caribbean region every year during the summer months causing an increase in PM10 concentrations and by consequence degradation of air quality. During African dust (AD) incursions at the Caribbean region, PM10 concentration could exceeds the exposure limit of 50 µg/m³ 24-hour mean established by the World Health Organization (WHO). To have a better understanding of the impacts of AD particles to climate and public health at the Caribbean region it is necessary to study and determine the spatial and temporal distribution of dust particles. In order to address this, aerosols samples were collected during and absence of AD incursions during the summer of 2017 using a Hi-Volume (Hi-Vol) sampler for total suspended particles (TSP) at two sampling stations in Puerto Rico. The first station is a marine site located at Cabezas de San Juan (CSJ) Nature Reserve in Fajardo, and the second station is an urban site located at the Facundo Bueso (FB) building at the University of Puerto Rico-Rio Piedras. Aerosol samples were collected using Whatman 41 grade filters from which we determined the concentration of dust particles and the water-soluble ions (e.g., Na+, NH4+, Ca+2, Cl-, SO4-2) in the presence and absence of LRTAD particles. Saharan Air Layer (SAL) imagery, the results from the air mass backward trajectories calculated with the NOAA Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT), and the spectral coefficients from measurements at CSJ were used to monitor and confirm the presence of air masses coming from North Africa. Average dust concentrations using the Stacked-Filter Units (SFUs) at CSJ are around 4 μg/m3. LRTAD concentrations and ionic speciation results using the Hi-Vol for the marine and urban sites will be presented at the conference.

  12. AN AFFINE-INVARIANT SAMPLER FOR EXOPLANET FITTING AND DISCOVERY IN RADIAL VELOCITY DATA

    International Nuclear Information System (INIS)

    Hou Fengji; Hogg, David W.; Goodman, Jonathan; Weare, Jonathan; Schwab, Christian

    2012-01-01

    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.

  13. An Introduction to the DA-T Gibbs Sampler for the Two-Parameter Logistic (2PL Model and Beyond

    Directory of Open Access Journals (Sweden)

    Gunter Maris

    2005-01-01

    Full Text Available 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 DAT 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 the 2PL may be used to build, quite easily, Gibbs samplers for other IRT models. Furthermore, the paper contains a novel, intuitive derivation of the Gibbs sampler and could be read for a graduate course on sampling.

  14. Fractal dust grains in plasma

    International Nuclear Information System (INIS)

    Huang, F.; Peng, R. D.; Liu, Y. H.; Chen, Z. Y.; Ye, M. F.; Wang, L.

    2012-01-01

    Fractal dust grains of different shapes are observed in a radially confined magnetized radio frequency plasma. The fractal dimensions of the dust structures in two-dimensional (2D) horizontal dust layers are calculated, and their evolution in the dust growth process is investigated. It is found that as the dust grains grow the fractal dimension of the dust structure decreases. In addition, the fractal dimension of the center region is larger than that of the entire region in the 2D dust layer. In the initial growth stage, the small dust particulates at a high number density in a 2D layer tend to fill space as a normal surface with fractal dimension D = 2. The mechanism of the formation of fractal dust grains is discussed.

  15. A Passive Diffusion Sampler for HT- and HTO-in-Air

    International Nuclear Information System (INIS)

    Surette, R.A.; Nunes, J.C.

    2005-01-01

    Fusion research and tritium removal facilities potentially handle large inventories of tritium gas (HT). If any HT is released into the workplace, a fraction may be converted to tritiated water vapour (HTO). A convenient method to determine the activity concentration of each species is necessary to assess the potential hazard since the radiological hazard of HTO is more than 10 4 that due to HT. Passive samplers for measuring tritiated water vapour (HTO) have been shown to be suitable for use indoors and outdoors. These simple samplers consist of a standard 20-mL liquid scintillation vial with a diffusion orifice that determines the sampling rate.The total tritium samplers described herein are passive or diffusion samplers that contain a small amount of AECL-proprietary wet-proofed catalyst fixed to the underside of the sampling heads to allow conversion of the HT to HTO that is subsequently collected in the sink, (HTO), in the bottom of the sampler. After an appropriate sampling time, liquid scintillation cocktail is added to the vial and the activity collected determined by liquid scintillation analysis. When used in conjunction with the conventional HTO passive sampler the difference between the total and HTO samplers can be used to determine the HT fraction ((HT+HTO) - HTO HT). The sampling rates for the modified diffusion sampler were measured to be 4.6 and 8.1 L/d for HTO and HT, respectively. For a fifteen-minute sampling period, passive samplers can be used to measure tritium activity concentrations from 37 kBq/m 3 to 115 MBq/m 3

  16. Sahara Dust Cloud

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Dust Particles Click on the image for Quicktime movie from 7/15-7/24 A continent-sized cloud of hot air and dust originating from the Sahara Desert crossed the Atlantic Ocean and headed towards Florida and the Caribbean. A Saharan Air Layer, or SAL, forms when dry air and dust rise from Africa's west coast and ride the trade winds above the Atlantic Ocean. These dust clouds are not uncommon, especially during the months of July and August. They start when weather patterns called tropical waves pick up dust from the desert in North Africa, carry it a couple of miles into the atmosphere and drift westward. In a sequence of images created by data acquired by the Earth-orbiting Atmospheric Infrared Sounder ranging from July 15 through July 24, we see the distribution of the cloud in the atmosphere as it swirls off of Africa and heads across the ocean to the west. Using the unique silicate spectral signatures of dust in the thermal infrared, AIRS can detect the presence of dust in the atmosphere day or night. This detection works best if there are no clouds present on top of the dust; when clouds are present, they can interfere with the signal, making it much harder to detect dust as in the case of July 24, 2005. In the Quicktime movie, the scale at the bottom of the images shows +1 for dust definitely detected, and ranges down to -1 for no dust detected. The plots are averaged over a number of AIRS observations falling within grid boxes, and so it is possible to obtain fractional numbers. [figure removed for brevity, see original site] Total Water Vapor in the Atmosphere Around the Dust Cloud Click on the image for Quicktime movie The dust cloud is contained within a dry adiabatic layer which originates over the Sahara Desert. This Saharan Air Layer (SAL) advances Westward over the Atlantic Ocean, overriding the cool, moist air nearer the surface. This burst of very dry air is visible in the AIRS retrieved total water

  17. Engineering Task Plan for Preparing the Type 4 In Situ Vapor Samplers (ISVS) for Use

    International Nuclear Information System (INIS)

    BOGER, R.M.

    2000-01-01

    The DOE has identified a need to sample vapor space and exhaust ducts of several waste tanks The In-Situ Vapor Sampling (ISVS) Type IV vapor sampling cart has been identified as the appropriate monitoring tool. The ISVS carts have been out of service for a number of years. This ETP outlines the work to be performed to ready the type IV gas sampler for operation Characterization Engineering will evaluate the Type IV gas sampler carts to determine their state of readiness and will proceed to update procedures and equipment documentation to make the sampler operationally acceptable

  18. Electrodynamic Dust Shield Demonstrator

    Science.gov (United States)

    Stankie, Charles G.

    2013-01-01

    The objective of the project was to design and manufacture a device to demonstrate a new technology developed by NASA's Electrostatics and Surface Physics Laboratory. The technology itself is a system which uses magnetic principles to remove regolith dust from its surface. This project was to create an enclosure that will be used to demonstrate the effectiveness of the invention to The Office of the Chief Technologist. ONE of the most important challenges of space exploration is actually caused by something very small and seemingly insignificant. Dust in space, most notably on the moon and Mars, has caused many unforeseen issues. Dirt and dust on Earth, while a nuisance, can be easily cleaned and kept at bay. However, there is considerably less weathering and erosion in space. As a result, the microscopic particles are extremely rough and abrasive. They are also electrostatically charged, so they cling to everything they make contact with. This was first noted to be a major problem during the Apollo missions. Dust would stick to the spacesuits, and could not be wiped off as predicted. Dust was brought back into the spacecraft, and was even inhaled by astronauts. This is a major health hazard. Atmospheric storms and other events can also cause dust to coat surfaces of spacecraft. This can cause abrasive damage to the craft. The coating can also reduce the effectiveness of thermal insulation and solar panels.' A group of engineers at Kennedy Space Center's Electrostatics and Surface Physics Laboratory have developed a new technology, called the Electrodynamic Dust Shield, to help alleviate these problems. It is based off of the electric curtain concept developed at NASA in 1967. "The EDS is an active dust mitigation technology that uses traveling electric fields to transport electrostatically charged dust particles along surfaces. To generate the traveling electric fields, the EDS consists of a multilayer dielectric coating with an embedded thin electrode grid

  19. Stardust Interstellar Preliminary Examination (ISPE)

    Science.gov (United States)

    Westphal, A. J.; Allen, C.; Bajt, S.; Basset, R.; Bastien, R.; Bechtel, H.; Bleuet, P.; Borg, J.; Brenker F.; Bridges, J.

    2009-01-01

    In January 2006 the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, C omet 81P/Wild2, and a collector dedicated to the capture and return o f contemporary interstellar dust. Both collectors were approximately 0.1m(exp 2) in area and were composed of aerogel tiles (85% of the co llecting area) and aluminum foils. The Stardust Interstellar Dust Col lector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 m(exp 2-) day during two periods before the co metary encounter. The Stardust Interstellar Preliminary Examination ( ISPE) is a three-year effort to characterize the collection using no ndestructive techniques. The ISPE consists of six interdependent proj ects: (1) Candidate identification through automated digital microsco py and a massively distributed, calibrated search (2) Candidate extr action and photodocumentation (3) Characterization of candidates thro ugh synchrotronbased FourierTranform Infrared Spectroscopy (FTIR), S canning XRay Fluoresence Microscopy (SXRF), and Scanning Transmission Xray Microscopy (STXM) (4) Search for and analysis of craters in f oils through FESEM scanning, Auger Spectroscopy and synchrotronbased Photoemission Electron Microscopy (PEEM) (5) Modeling of interstell ar dust transport in the solar system (6) Laboratory simulations of h ypervelocity dust impacts into the collecting media

  20. Oil refinery dusts: morphological and size analysis by TEM.

    Science.gov (United States)

    Sielicki, Przemysław; Janik, Helena; Guzman, Agnieszka; Broniszewski, Mieczysław; Namieśnik, Jacek

    2011-03-01

    The objectives of this work were to develop a means of sampling atmospheric dusts on the premises of an oil refinery for electron microscopic study to carry out preliminary morphological analyses and to compare these dusts with those collected at sites beyond the refinery limits. Carbon and collodion membranes were used as a support for collection of dust particles straight on transmission electron microscopy (TEM) grids. Micrographs of the dust particles were taken at magnifications from ×4,000 to ×80,000 with a Tesla BS500 transmission electron microscope. Four parameters were defined on the basis of the micrographs: surface area, Feret diameter, circumference, and shape coefficient. The micrographs and literature data were used to classify the atmospheric dusts into six groups: particles with an irregular shape and rounded edges; particles with an irregular shape and sharp edges; soot and its aggregates; spherical particles; singly occurring, ultrafine dust particles; and particles not allocated to any of the previous five groups. The types of dusts found in all the samples were similar, although differences did exist between the various morphological parameters. Dust particles with the largest Feret diameter were present in sample 3 (mean, 0.739 μm)-these were collected near the refinery's effluent treatment plant. The particles with the smallest diameter were found in the sample that had been intended to be a reference sample for the remaining results (mean, 0.326 μm). The dust particles collected in the refinery had larger mean Feret diameters, even 100% larger, than those collected beyond it. Particles with diameters from 0.1 to 0.2 μm made up the most numerous group in all the samples collected in the refinery.

  1. Oil refinery dusts: morphological and size analysis by TEM

    Energy Technology Data Exchange (ETDEWEB)

    Sielicki, Przemyslaw; Janik, Helena; Guzman, Agnieszka [Gdansk University of Technology, Department of Polymer Technology, Chemical Faculty, Gdansk (Poland); Broniszewski, Mieczyslaw [Environmental Protection Office, Lotos Group, Gdansk (Poland); Namiesnik, Jacek [Gdansk University of Technology, Department of Analytical Chemistry, Chemical Faculty, Gdansk (Poland)

    2011-03-15

    The objectives of this work were to develop a means of sampling atmospheric dusts on the premises of an oil refinery for electron microscopic study to carry out preliminary morphological analyses and to compare these dusts with those collected at sites beyond the refinery limits. Carbon and collodion membranes were used as a support for collection of dust particles straight on transmission electron microscopy (TEM) grids. Micrographs of the dust particles were taken at magnifications from x 4,000 to x 80,000 with a Tesla BS500 transmission electron microscope. Four parameters were defined on the basis of the micrographs: surface area, Feret diameter, circumference, and shape coefficient. The micrographs and literature data were used to classify the atmospheric dusts into six groups: particles with an irregular shape and rounded edges; particles with an irregular shape and sharp edges; soot and its aggregates; spherical particles; singly occurring, ultrafine dust particles; and particles not allocated to any of the previous five groups. The types of dusts found in all the samples were similar, although differences did exist between the various morphological parameters. Dust particles with the largest Feret diameter were present in sample 3 (mean, 0.739 {mu}m) - these were collected near the refinery's effluent treatment plant. The particles with the smallest diameter were found in the sample that had been intended to be a reference sample for the remaining results (mean, 0.326 {mu}m). The dust particles collected in the refinery had larger mean Feret diameters, even 100% larger, than those collected beyond it. Particles with diameters from 0.1 to 0.2 {mu}m made up the most numerous group in all the samples collected in the refinery. (orig.)

  2. Sand and Dust Testing of Wheeled and Tracked Vehicles and Stationary Equipment

    Science.gov (United States)

    2009-11-18

    Vacuum pump Flow meter Measurement of dust mass ±2 percent ±4 percent ±0.0005 g Weight of air cleaner element ±0.5 percent (Total estimated error...samplers should be set to a flow rate that is isokinetic ) on the front of the vehicle, in the center of the grill or windshield, or the center of...3) Record the test bed vehicle odometer and hour meter reading. (4) Document the condition of the vehicle interior, exterior, and all

  3. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1980-01-01

    A two-component dust model is suggested to explain the infrared emission from planetary nebulae. A cold dust component located in the extensive remnant of the red-giant envelope exterior to the visible nebula is responsible for the far-infrared emission. A ward dust component, which is condensed after the formation of the planetary nebula and confined within the ionized gas shell, emits most of the near- and mid-infrared radiation. The observations of NGC 7027 are shown to be consisten with such a model. The correlation of silicate emission in several planetary nebulae with an approximately +1 spectral index at low radio frequencies suggests that both the silicate and radio emissions originate from the remnant of the circumstellar envelope of th precursor star and are observable only while the planetary nebula is young. It is argued that oxygen-rich stars as well as carbon-rich stars can be progenitors of planetary nebulae

  4. Interstellar dust and extinction

    International Nuclear Information System (INIS)

    Mathis, J.S.

    1990-01-01

    It is noted that the term interstellar dust refers to materials with rather different properties, and that the mean extinction law of Seaton (1979) or Savage and Mathis (1979) should be replaced by the expression given by Cardelli et al. (1989), using the appropriate value of total-to-selective extinction. The older laws were appropriate for the diffuse ISM but dust in clouds differs dramatically in its extinction law. Dust is heavily processed while in the ISM by being included within clouds and cycled back into the diffuse ISM many times during its lifetime. Hence, grains probably reflect only a trace of their origin, although meteoritic inclusions with isotopic anomalies demonstrate that some tiny particles survive intact from a supernova origin to the present. 186 refs

  5. Dust control for draglines

    Energy Technology Data Exchange (ETDEWEB)

    Grad, P.

    2009-09-15

    Monitoring dust levels inside draglines reveals room for improvement in how filtration systems are used and maintained. The Australian firm BMT conducted a field test program to measure airflow parameters, dust fallout rates and dust concentrations, inside and outside the machine house, on four draglines and one shovel. The study involved computational fluid dynamics (CFD) simulations. The article describes how the tests were made and gives results. It was not possible to say which of the two main filtration systems currently used on Australian draglines - Dynavane or Floseps - performs better. It would appear that more frequent maintenance and cleaning would increase the overall filtration performance and systems could be susceptible to repeat clogging in a short time. 2 figs., 1 photos.

  6. DustEM: Dust extinction and emission modelling

    Science.gov (United States)

    Compiègne, M.; Verstraete, L.; Jones, A.; Bernard, J.-P.; Boulanger, F.; Flagey, N.; Le Bourlot, J.; Paradis, D.; Ysard, N.

    2013-07-01

    DustEM computes the extinction and the emission of interstellar dust grains heated by photons. It is written in Fortran 95 and is jointly developed by IAS and CESR. The dust emission is calculated in the optically thin limit (no radiative transfer) and the default spectral range is 40 to 108 nm. The code is designed so dust properties can easily be changed and mixed and to allow for the inclusion of new grain physics.

  7. Dust-Plasma Interactions

    International Nuclear Information System (INIS)

    Rosenberg, M.

    2010-01-01

    The objective of our theoretical research under this grant over the past 3 years was to develop new understanding in a range of topics in the physics of dust-plasma interactions, with application to space and the laboratory. We conducted studies related to the physical properties of dust, waves and instabilities in both weakly coupled and strongly coupled dusty plasmas, and innovative possible applications. A major consideration in our choice of topics was to compare theory with experiments or observations, and to motivate new experiments, which we believe is important for developing this relatively new field. Our research is summarized, with reference to our list of journal publications.

  8. Design of data sampler in intelligent physical start-up system for nuclear reactor

    International Nuclear Information System (INIS)

    Wang Yinli; Ling Qiu

    2007-01-01

    It introduces the design of data sampler in intelligent physical start-up system for nuclear reactor. The hardware frame taking STμPSD3234A as the core and the firmware design based on USB interface are discussed. (authors)

  9. The Winfrith portable self-contained air samplers, type W.A.S. 1

    International Nuclear Information System (INIS)

    Cavell, I.W.

    1961-11-01

    This memorandum describes a self-contained air sampler for collecting samples of airborne particulates on a standard 6 centimetre filter paper. Its construction, use and performance are discussed. (author)

  10. Reconciling PM10 analyses by different sampling methods for Iron King Mine tailings dust.

    Science.gov (United States)

    Li, Xu; Félix, Omar I; Gonzales, Patricia; Sáez, Avelino Eduardo; Ela, Wendell P

    2016-03-01

    The overall project objective at the Iron King Mine Superfund site is to determine the level and potential risk associated with heavy metal exposure of the proximate population emanating from the site's tailings pile. To provide sufficient size-fractioned dust for multi-discipline research studies, a dust generator was built and is now being used to generate size-fractioned dust samples for toxicity investigations using in vitro cell culture and animal exposure experiments as well as studies on geochemical characterization and bioassay solubilization with simulated lung and gastric fluid extractants. The objective of this study is to provide a robust method for source identification by comparing the tailing sample produced by dust generator and that collected by MOUDI sampler. As and Pb concentrations of the PM10 fraction in the MOUDI sample were much lower than in tailing samples produced by the dust generator, indicating a dilution of Iron King tailing dust by dust from other sources. For source apportionment purposes, single element concentration method was used based on the assumption that the PM10 fraction comes from a background source plus the Iron King tailing source. The method's conclusion that nearly all arsenic and lead in the PM10 dust fraction originated from the tailings substantiates our previous Pb and Sr isotope study conclusion. As and Pb showed a similar mass fraction from Iron King for all sites suggesting that As and Pb have the same major emission source. Further validation of this simple source apportionment method is needed based on other elements and sites.

  11. Control of harmful dust in coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Goddard, B; Bower, K; Mitchell, D

    1973-01-01

    This handbook consists of a series of short chapters devoted to: sources of airborne dust; dust standards and methods of sampling; dust prevention on mechanized faces; ventilation and dust extraction; distribution and use of water; dust control on mechanized faces; dust control in drivages and headings; drilling and shotfiring; dust control in transport; some outbye dust control techniques (hygroscopic salts, impingement curtains); water infusion; personal protective equipment. (CIS Abstr.)

  12. Dust evolution in protoplanetary disks

    OpenAIRE

    Gonzalez , Jean-François; Fouchet , Laure; T. Maddison , Sarah; Laibe , Guillaume

    2007-01-01

    6 pages, 5 figures, to appear in the Proceedings of IAU Symp. 249: Exoplanets: Detection, Formation and Dynamics (Suzhou, China); International audience; We investigate the behaviour of dust in protoplanetary disks under the action of gas drag using our 3D, two-fluid (gas+dust) SPH code. We present the evolution of the dust spatial distribution in global simulations of planetless disks as well as of disks containing an already formed planet. The resulting dust structures vary strongly with pa...

  13. Respirable versus inhalable dust sampling

    International Nuclear Information System (INIS)

    Hondros, J.

    1987-01-01

    The ICRP uses a total inhalable dust figure as the basis of calculations on employee lung dose. This paper was written to look at one aspect of the Olympic Dam dust situation, namely, the inhalable versus respirable fraction of the dust cloud. The results of this study will determine whether it is possible to use respirable dust figures, as obtained during routine monitoring to help in the calculations of employee exposure to internal radioactive contaminants

  14. Paleo-dust insights onto dust-climate interactions

    Science.gov (United States)

    Albani, S.; Mahowald, N. M.

    2017-12-01

    Mineral dust emissions are affected by changing climate conditions, and in turn dust impacts the atmospheric radiation budget, clouds and biogeochemical cycles. Climate and public health dust-related issues call for attention on the fate of the dust cycle in the future, and the representation of the dust cycle is now part of the strategy of the Paleoclimate Modelling Intercomparison Project phase 4 and the Coupled Model Intercomparison Project phase 6 (PMIP4-CMIP6). Since mineral aerosols are one of the most important natural aerosols, understanding past dust responses to climate in the paleoclimate will allow us to better understand mineral aerosol feedbacks with climate and biogeochemistry in the Anthropocene. Modern observations and paleoclimate records offer the possibility of multiple, complementary views on the global dust cycle, and allow to validate and/or constrain the numerical representation of dust in climate and Earth system models. We present our results from a set of simulations with the Community Earth System Model for different climate states, including present and past climates such as the pre-industrial, the mid-Holocene and the Last Glacial Maximum. A set of simulations including a prognostic dust cycle was thoroughly compared with a wide set of present day observations from different platforms and regions, in order to realistically constrain the magnitude of dust load, surface concentration, deposition, optical properties, and particle size distributions. The magnitude of emissions for past climate regimes was constrained based on compilations of paleodust mass accumulation rates and size distributions, as well as based on information on dust provenance. The comparison with a parallel set of simulations without dust allows estimating the impacts of dust on surface climate. We analyze impacts of dust on the mean and variability of surface temperature and precipitation in each climate state, as well as the impacts that changing dust emissions had

  15. DUST-BATHING BEHAVIORS OF AFRICAN HERBIVORES AND THE POTENTIAL RISK OF INHALATIONAL ANTHRAX.

    Science.gov (United States)

    Barandongo, Zoe R; Mfune, John K E; Turner, Wendy C

    2018-01-01

    :  Anthrax in herbivorous wildlife and livestock is generally assumed to be transmitted via ingestion or inhalation of Bacillus anthracis spores. Although recent studies have highlighted the importance of the ingestion route for anthrax transmission, little is known about the inhalational route in natural systems. Dust bathing could aerosolize soilborne pathogens such as B. anthracis, exposing dust-bathing individuals to inhalational infections. We investigated the potential role of dust bathing in the transmission of inhalational anthrax to herbivorous wildlife in Etosha National Park, Namibia, an area with endemic seasonal anthrax outbreaks. We 1) cultured soils from dust-bathing sites for the presence and concentration of B. anthracis spores, 2) monitored anthrax carcass sites, the locations with the highest B. anthracis concentrations, for evidence of dust bathing, including a site where a zebra died of anthrax on a large dust bath, and 3) characterized the ecology and seasonality of dust bathing in plains zebra ( Equus quagga), blue wildebeest ( Connochaetes taurinus), and African savanna elephant ( Loxodonta africana) using a combination of motion-sensing camera traps and direct observations. Only two out of 83 dust-bath soils were positive for B. anthracis, both with low spore concentrations (≤20 colony-forming units per gram). We also detected no evidence of dust baths occurring at anthrax carcass sites, perhaps due to carcass-induced changes in soil composition that may deter dust bathing. Finally, despite observing some seasonal variation in dust bathing, preliminary evidence suggests that the seasonality of dust bathing and anthrax mortalities are not correlated. Thus, although dust bathing creates a dramatic cloud of aerosolized soil around an individual, our microbiologic, ecologic, and behavioral results in concert demonstrate that dust bathing is highly unlikely to transmit inhalational anthrax infections.

  16. Development of materials resistant to metal dusting degradation.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Zeng, Z.

    2006-04-24

    Metal dusting corrosion has been a serious problem in the petroleum and petrochemical industries, such as reforming and syngas production systems. This form of deterioration has led to worldwide material loss for 50 years. For the past three years, we have studied the mechanism of metal dusting for Fe- and Ni-base alloys. In this report, we present a correlation between the weight loss and depth of pits that form in Ni-base alloys. Nickel-base alloys were also tested at 1 and 14.8 atm (210 psi), in a high carbon activity environment. Higher system pressure was found to accelerate corrosion in most Ni-base alloys. To reduce testing time, a pre-pitting method was developed. Mechanical scratches on the alloy surface led to fast metal dusting corrosion. We have also developed preliminary data on the performance of weldments of several Ni-base alloys in a metal dusting environment. Finally, Alloy 800 tubes and plates used in a reformer plant were examined by scanning electron microscopy, energy dispersive X-ray, and Raman spectroscopy. The oxide scale on the surface of the Alloy 800 primarily consists of Fe{sub 1+x}Cr{sub 2-X}O{sub 4} spinel phase with high Fe content. Carbon can diffuse through this oxide scale. It was discovered that the growth of metal dusting pits could be stopped by means of a slightly oxidized alloy surface. This leads to a new way to solve metal dusting problem.

  17. Relationships between Personal Measurements of 'Total' Dust, Respirable, Thoracic, and Inhalable Aerosol Fractions in the Cement Production Industry.

    Science.gov (United States)

    Notø, Hilde P; Nordby, Karl-Christian; Eduard, Wijnand

    2016-05-01

    The aims of this study were to examine the relationships and establish conversion factors between 'total' dust, respirable, thoracic, and inhalable aerosol fractions measured by parallel personal sampling on workers from the production departments of cement plants. 'Total' dust in this study refers to aerosol sampled by the closed face 37-mm Millipore filter cassette. Side-by-side personal measurements of 'total' dust and respirable, thoracic, and inhalable aerosol fractions were performed on workers in 17 European and Turkish cement plants. Simple linear and mixed model regressions were used to model the associations between the samplers. The total number of personal samples collected on 141 workers was 512. Of these 8.4% were excluded leaving 469 for statistical analysis. The different aerosol fractions contained from 90 to 130 measurements and-side-by side measurements of all four aerosol fractions were collected on 72 workers.The median ratios between observed results of the respirable, 'total' dust, and inhalable fractions relative to the thoracic aerosol fractions were 0.51, 2.4, and 5.9 respectively. The ratios between the samplers were not constant over the measured concentration range and were best described by regression models. Job type, position of samplers on left or right shoulder and plant had no substantial effect on the ratios. The ratios between aerosol fractions changed with different air concentrations. Conversion models for estimation of the fractions were established. These models explained a high proportion of the variance (74-91%) indicating that they are useful for the estimation of concentrations based on measurements of a different aerosol fraction. The calculated uncertainties at most observed concentrations were below 30% which is acceptable for comparison with limit values (EN 482, 2012). The cement industry will therefore be able to predict the health related aerosol fractions from their former or future measurements of one of the

  18. A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

    International Nuclear Information System (INIS)

    Tao, S.; Liu, Y.N.; Lang, C.; Wang, W.T.; Yuan, H.S.; Zhang, D.Y.; Qiu, W.X.; Liu, J.M.; Liu, Z.G.; Liu, S.Z.; Yi, R.; Ji, M.; Liu, X.X.

    2008-01-01

    A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test. - A novel directional passive air sampler was developed and tested for monitoring PAHs in air masses from different directions

  19. Radial diffusive sampler for the determination of 8-h ambient ozone concentrations

    International Nuclear Information System (INIS)

    Plaisance, H.; Gerboles, M.; Piechocki, A.; Detimmerman, F.; Saeger, E. de

    2007-01-01

    The 8-h ozone radial diffusive sampler was evaluated according to the CEN protocol for the validation of diffusive samplers. All the parameters regarding the sampler characteristics were found to be consistent with the requirements of this protocol apart from the blank value, which must be evaluated and subtracted at each sampling. The nominal uptake rate was determined in laboratory conditions. However, the uptake rate depends on the mass uptake, temperature, humidity and on the combination of temperature and humidity. Based on laboratory experiments, an empirical model has been established which improved the agreement between the radial sampler and the reference method. This improvement was observed under several different meteorological and emission conditions of sampling. By using the model equation of uptake rate, the data quality objective of 30% for the expanded uncertainty included in the O 3 European Directive, is easily attained. Therefore, the sampler represents an appropriate indicative method. - A passive sampler has been fully validated for monitoring 8-h ozone concentrations in ambient air

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Windblown Dust Deposition Forecasting and Spread of Contamination around Mine Tailings.

    Science.gov (United States)

    Stovern, Michael; Guzmán, Héctor; Rine, Kyle P; Felix, Omar; King, Matthew; Ela, Wendell P; Betterton, Eric A; Sáez, Avelino Eduardo

    2016-02-01

    Wind erosion, transport and deposition of windblown dust from anthropogenic sources, such as mine tailings impoundments, can have significant effects on the surrounding environment. The lack of vegetation and the vertical protrusion of the mine tailings above the neighboring terrain make the tailings susceptible to wind erosion. Modeling the erosion, transport and deposition of particulate matter from mine tailings is a challenge for many reasons, including heterogeneity of the soil surface, vegetative canopy coverage, dynamic meteorological conditions and topographic influences. In this work, a previously developed Deposition Forecasting Model (DFM) that is specifically designed to model the transport of particulate matter from mine tailings impoundments is verified using dust collection and topsoil measurements. The DFM is initialized using data from an operational Weather Research and Forecasting (WRF) model. The forecast deposition patterns are compared to dust collected by inverted-disc samplers and determined through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. The methodology and approach employed in this work can be generalized to other contaminated sites from which dust transport to the local environment can be assessed as a potential route for human exposure.

  2. Erosion of dust aggregates

    NARCIS (Netherlands)

    Seizinger, A.; Krijt, S.; Kley, W.

    2013-01-01

    Aims: The aim of this work is to gain a deeper insight into how much different aggregate types are affected by erosion. Especially, it is important to study the influence of the velocity of the impacting projectiles. We also want to provide models for dust growth in protoplanetary disks with simple

  3. Dust-Plasma Interactions

    International Nuclear Information System (INIS)

    Rosenberg, Marelene

    2005-01-01

    Our theoretical research on dust-plasma interactions has concentrated on three main areas: (a)studies of grain charging and applications; (b) waves and instabilities in weakly correlated dusty plasma with applications to space and laboratory plasmas; (c) waves in strongly coupled dusty plasmas.

  4. From dust to life

    Science.gov (United States)

    Wickramasinghe, Chandra

    After initially challenging the dirty-ice theory of interstellar grains, Fred Hoyle and the present author proposed carbon (graphite) grains, mixtures of refractory grains, organic polymers, biochemicals and finally bacterial grains as models of interstellar dust. The present contribution summarizes this trend and reviews the main arguments supporting a modern version of panspermia.

  5. iDNA screening: Disease vectors as vertebrate samplers.

    Science.gov (United States)

    Kocher, Arthur; de Thoisy, Benoit; Catzeflis, François; Valière, Sophie; Bañuls, Anne-Laure; Murienne, Jérôme

    2017-11-01

    In the current context of global change and human-induced biodiversity decline, there is an urgent need for developing sampling approaches able to accurately describe the state of biodiversity. Traditional surveys of vertebrate fauna involve time-consuming and skill-demanding field methods. Recently, the use of DNA derived from invertebrate parasites (leeches and blowflies) was suggested as a new tool for vertebrate diversity assessment. Bloodmeal analyses of arthropod disease vectors have long been performed to describe their feeding behaviour, for epidemiological purposes. On the other hand, this existing expertise has not yet been applied to investigate vertebrate fauna per se. Here, we evaluate the usefulness of hematophagous dipterans as vertebrate samplers. Blood-fed sand flies and mosquitoes were collected in Amazonian forest sites and analysed using high-throughput sequencing of short mitochondrial markers. Bloodmeal identifications highlighted contrasting ecological features and feeding behaviour among dipteran species, which allowed unveiling arboreal and terrestrial mammals of various body size, as well as birds, lizards and amphibians. Additionally, lower vertebrate diversity was found in sites undergoing higher levels of human-induced perturbation. These results suggest that, in addition to providing precious information on disease vector host use, dipteran bloodmeal analyses may represent a useful tool in the study of vertebrate communities. Although further effort is required to validate the approach and consider its application to large-scale studies, this first work opens up promising perspectives for biodiversity monitoring and eco-epidemiology. © 2017 John Wiley & Sons Ltd.

  6. Modelling dust transport in tokamaks

    International Nuclear Information System (INIS)

    Martin, J.D.; Martin, J.D.; Bacharis, M.; Coppins, M.; Counsell, G.F.; Allen, J.E.; Counsell, G.F.

    2008-01-01

    The DTOKS code, which models dust transport through tokamak plasmas, is described. The floating potential and charge of a dust grain in a plasma and the fluxes of energy to and from it are calculated. From this model, the temperature of the dust grain can be estimated. A plasma background is supplied by a standard tokamak edge modelling code (B2SOLPS5.0), and dust transport through MAST (the Mega-Amp Spherical Tokamak) and ITER plasmas is presented. We conclude that micron-radius tungsten dust can reach the separatrix in ITER. (authors)

  7. Characteristics and Sampling Efficiencies of Two Impactor Bioaerosol Samplers: MAS-100(Registered) (Microbial Air Monitoring System) and Single-Stage Andersen Viable Microbial Samplers

    National Research Council Canada - National Science Library

    Hottell, K

    2004-01-01

    .... A petri dish with agar is used as the impaction surface for these samplers. The MAS-l00 is a single-stage impactor that aspirates air through a 400-hole perforated entry plate onto an agar plate at an airflow rate of 100 L/min...

  8. Experimental determination of the unattached radon daughter fraction and dust size distribution in some Canadian uranium mines

    International Nuclear Information System (INIS)

    Bigu, J.; Kirk, J.

    1982-01-01

    The unattached radon daughter fraction has been experimentally determined in some Canadian uranium mines. Two experimental methods have been used, the wire screen method and a diffusion sampler based on Mercer's theory of diffusional deposition on parallel circular plates. Experiments were conducted in 'non-diesel' and 'diesel' areas of the mines, i.e. locations where mining was done with diesel machinery. Unattached fractions ranged from about 2-8 per cent for non-diesel area. For diesel areas the unattached fraction was substantially lower, less than about one per cent. The aerosol concentration in the range 0.0015 - 0.13 μm was measured with a condensation nuclei counter. Dust concentration was determined with conventional samplers. Particle size distribution in the respirable range was determined with a fine particle spectrometer in conjunction with eriometric techniques

  9. Magnetic Measurements of Atmospheric Dust Deposition in Soils

    Science.gov (United States)

    Kapička, Aleš; Petrovský, Eduard; Grison, Hana; Podrázský, Vilém; Křížek, Pavel

    2010-05-01

    Atmospheric dust of anthropogenic origin contains significant portion of minerals characterized by ferrimagnetic properties [1,2]. These minerals, mostly iron oxides, can serve as tracers of industrial pollutants in soil layers. Moreover, recent results, e.g., [3,4] show significant correlation between concentration-dependent magnetic parameters (e.g., low-field magnetic susceptibility) and concentration of heavy metals (e.g., Pb, Zn, Cd). In our paper we have investigated magnetic properties of depth soil profiles from Krušné hory Mountains (Czech Republic), which belong to a highly contaminated, so-called Black Triangle in central Europe. Emissions are determined by considerable concentration of big sources of pollution (power plants burning fossil fuel, metallurgical and chemical industry). Increased values of magnetic susceptibility (25 - 200 × 10-5 SI) were clearly identified in the top-soil layers. Thermomagnetic analyses and SEM observation indicate that the accumulated anthropogenic ferrimagnetics dominate these layers. Magnetic enhancement is limited to depths of 4-7 cm below the soil surface, usually in F-H or top of Ah soil horizons; deeper soil horizons contain mainly magnetically weak materials and are characterized by much lower values of susceptibility (up to 30 × 10-5 SI). Significant magnetic parameters (e.g., Curie temperature Tc) and SEM results of contaminated topsoils are comparable with magnetic parameters of atmospheric dust, collected (using high-volume samplers) at the same localities.

  10. Ammonia concentration modeling based on retained gas sampler data

    International Nuclear Information System (INIS)

    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. Development of a new passive sampler based on diffusive milligel beads for copper analysis in water

    International Nuclear Information System (INIS)

    Perez, M.; Reynaud, S.; Lespes, G.; Potin-Gautier, M.; Mignard, E.; Chéry, P.; Schaumlöffel, D.; Grassl, B.

    2015-01-01

    A new passive sampler was designed and characterized for the determination of free copper ion (Cu 2+ ) concentration in aqueous solution. Each sampling device was composed of a set of about 30 diffusive milligel (DMG) beads. Milligel beads with incorporated cation exchange resin (Chelex) particles were synthetized using an adapted droplet-based millifluidic process. Beads were assumed to be prolate spheroids, with a diameter of 1.6 mm and an anisotropic factor of 1.4. The milligel was controlled in chemical composition of hydrogel (monomer, cross-linker, initiator and Chelex concentration) and characterized in pore size. Two types of sampling devices were developed containing 7.5% and 15% of Chelex, respectively, and 6 nm pore size. The kinetic curves obtained demonstrated the accumulation of copper in the DMG according to the process described in the literature as absorption (and/or adsorption) and release following the Fick's first law of diffusion. For their use in water monitoring, the typical physico-chemical characteristics of the samplers, i.e. the mass-transfer coefficient (k 0 ) and the sampler-water partition coefficient (K sw ), were determined based on a static exposure design. In order to determine the copper concentration in the samplers after their exposure, a method using DMG bead digestion combined to Inductively Coupled Plasma – Atomic Emission Spectrometry (ICP-AES) analysis was developed and optimized. The DMG devices proved to be capable to absorb free copper ions from an aqueous solution, which could be accurately quantified with a mean recovery of 99% and a repeatability of 7% (mean relative uncertainty). - Highlights: • Controlled geometry of new passive sampler with ellipsoidal shape. • Original manufacturing process based on droplet-based millifluidic device. • Pore size characterization of the sampler. • Mass-transfer and sampler-water partitioning coefficients by static exposure experiments

  12. Development of a new passive sampler based on diffusive milligel beads for copper analysis in water

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M.; Reynaud, S.; Lespes, G.; Potin-Gautier, M. [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France); Mignard, E. [CNRS-Solvay-Université Bordeaux, UMR5258, Laboratoire du Futur, 178 Avenue du Dr. A. Schweitzer, 33608 Pessac Cedex (France); Chéry, P. [Bordeaux Science Agro, 1 cours du Général De Gaulle, Gradignan, 33175 (France); Schaumlöffel, D. [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France); Grassl, B., E-mail: bruno.grassl@univ-pau.fr [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France)

    2015-08-26

    A new passive sampler was designed and characterized for the determination of free copper ion (Cu{sup 2+}) concentration in aqueous solution. Each sampling device was composed of a set of about 30 diffusive milligel (DMG) beads. Milligel beads with incorporated cation exchange resin (Chelex) particles were synthetized using an adapted droplet-based millifluidic process. Beads were assumed to be prolate spheroids, with a diameter of 1.6 mm and an anisotropic factor of 1.4. The milligel was controlled in chemical composition of hydrogel (monomer, cross-linker, initiator and Chelex concentration) and characterized in pore size. Two types of sampling devices were developed containing 7.5% and 15% of Chelex, respectively, and 6 nm pore size. The kinetic curves obtained demonstrated the accumulation of copper in the DMG according to the process described in the literature as absorption (and/or adsorption) and release following the Fick's first law of diffusion. For their use in water monitoring, the typical physico-chemical characteristics of the samplers, i.e. the mass-transfer coefficient (k{sub 0}) and the sampler-water partition coefficient (K{sub sw}), were determined based on a static exposure design. In order to determine the copper concentration in the samplers after their exposure, a method using DMG bead digestion combined to Inductively Coupled Plasma – Atomic Emission Spectrometry (ICP-AES) analysis was developed and optimized. The DMG devices proved to be capable to absorb free copper ions from an aqueous solution, which could be accurately quantified with a mean recovery of 99% and a repeatability of 7% (mean relative uncertainty). - Highlights: • Controlled geometry of new passive sampler with ellipsoidal shape. • Original manufacturing process based on droplet-based millifluidic device. • Pore size characterization of the sampler. • Mass-transfer and sampler-water partitioning coefficients by static exposure experiments.

  13. Field performance evaluation during fog-dominated wintertime of a newly developed denuder-equipped PM1 sampler.

    Science.gov (United States)

    Singh, Dharmendra Kumar; Lakshay; Gupta, Tarun

    2014-03-01

    This study presents the performance evaluation of a novel denuder-equipped PM1 (particles having aerodynamic diameter less than 1 μm) sampler, tested during fog-dominated wintertime, in the city of Kanpur, India. One PM1 sampler and one denuder-equipped PM1 sampler were co-located to collect ambient PM1 for 25 days. The mean PM1 mass concentration measured on foggy days with the PM1 sampler and the denuder-equipped PM1 sampler was found to be 165.95 and 135.48 μg/m(3), respectively. The mean PM1 mass concentration measured on clear days with the PM1 sampler and the denuder-equipped PM1 sampler was observed to be 159.66 and 125.14 μg/m(3), respectively. The mass concentration with denuder-fitted PM1 sampler for both foggy and clear days was always found less than the PM1 sampler. The same drift was observed in the concentrations of water-soluble ions and water-soluble organic carbon (WSOC). Moreover, it was observed that the use of denuder leads to a significant reduction in the PM positive artifact. The difference in the concentration of chemical species obtained by two samplers indicates that the PM1 sampler without denuder had overestimated the concentrations of chemical species in a worst-case scenario by almost 40 %. Denuder-fitted PM1 sampler can serve as a useful sampling tool in estimating the true values for nitrate, ammonium, potassium, sodium and WSOC present in the ambient PM.

  14. Field evaluation of a tailor-made new passive sampler for the determination of NO2 levels in ambient air.

    Science.gov (United States)

    Ozden, Ozlem; Dogeroglu, Tuncay

    2008-07-01

    This study describes the field evaluation of a tailor-made new glass passive sampler developed for the determination of NO(2), based on the collection on triethanolemine (TEA)-coated fibre filter paper. The sampler has been derived from a Palmes design. The overall uncertainty of the sampler was determined by using Griess-Saltzman ASTM D 1607 standard test method as a reference method. The agreement between the results of the passive sampler and the reference method was +/-7.90% with the correlation coefficient of 0.90. Method precision in terms of coefficient of variance (CV) for three simultaneously applied passive samplers was 8.80%. The uptake rate of NO(2) was found to be 2.49 ml/min in a very good agreement with the value calculated from theory (2.63 ml/min). Sampler detection limit was 1.99 microg/m(3) for an exposure period of 1 week and the sampler can be stored safely for a period of up to 6 weeks before exposure. A comparison of the sampler performance was conducted against a commercially available diffusion tube (Gradko diffusion tube). The results from the applied statistical paired t test indicated that there was no significant difference between the performances of two passive samplers (R (2) > 0.90). Also, another statistical comparison was carried out between the dark and transparent glass passive samplers. The results from the dark-colour sampler were higher than that from the transparent sampler (approximately 25%) during the summer season because of the possible photodegradation of NO(2)-TEA complex.

  15. The OPEnSampler: A Low-Cost, Low-Weight, Customizable and Modular Open Source 24-Unit Automatic Water Sampler

    Science.gov (United States)

    Nelke, M.; Selker, J. S.; Udell, C.

    2017-12-01

    Reliable automatic water samplers allow repetitive sampling of various water sources over long periods of time without requiring a researcher on site, reducing human error as well as the monetary and time costs of traveling to the field, particularly when the scale of the sample period is hours or days. The high fixed cost of buying a commercial sampler with little customizability can be a barrier to research requiring repetitive samples, such as the analysis of septic water pre- and post-treatment. DIY automatic samplers proposed in the past sacrifice maximum volume, customizability, or scope of applications, among other features, in exchange for a lower net cost. The purpose of this project was to develop a low-cost, highly customizable, robust water sampler that is capable of sampling many sources of water for various analytes. A lightweight aluminum-extrusion frame was designed and assembled, chosen for its mounting system, strength, and low cost. Water is drawn from two peristaltic pumps through silicone tubing and directed into 24 foil-lined 250mL bags using solenoid valves. A programmable Arduino Uno microcontroller connected to a circuit board communicates with a battery operated real-time clock, initiating sampling stages. Period and volume settings are programmable in-field by the user via serial commands. The OPEnSampler is an open design, allowing the user to decide what components to use and the modular theme of the frame allows fast mounting of new manufactured or 3D printed components. The 24-bag system weighs less than 10kg and the material cost is under $450. Up to 6L of sample water can be drawn at a rate of 100mL/minute in either direction. Faster flowrates are achieved by using more powerful peristaltic pumps. Future design changes could allow a greater maximum volume by filling the unused space with more containers and adding GSM communications to send real time status information.

  16. Dust storm, northern Mexico

    Science.gov (United States)

    1983-01-01

    This large dust storm along the left side of the photo, covers a large portion of the state of Coahuila, Mexico (27.5N, 102.0E). The look angle of this oblique photo is from the south to the north. In the foreground is the Sierra Madre Oriental in the states Coahuila and Nuevo Leon with the Rio Grande River, Amistad Reservoir and Texas in the background.

  17. Uncertainties in monitoring of SVOCs in air caused by within-sampler degradation during active and passive air sampling

    Science.gov (United States)

    Melymuk, Lisa; Bohlin-Nizzetto, Pernilla; Prokeš, Roman; Kukučka, Petr; Přibylová, Petra; Vojta, Šimon; Kohoutek, Jiří; Lammel, Gerhard; Klánová, Jana

    2017-10-01

    Degradation of semivolatile organic compounds (SVOCs) occurs naturally in ambient air due to reactions with reactive trace gases (e.g., ozone, NOx). During air sampling there is also the possibility for degradation of SVOCs within the air sampler, leading to underestimates of ambient air concentrations. We investigated the possibility of this sampling artifact in commonly used active and passive air samplers for seven classes of SVOCs, including persistent organic pollutants (POPs) typically covered by air monitoring programs, as well as SVOCs of emerging concern. Two active air samplers were used, one equipped with an ozone denuder and one without, to compare relative differences in mass of collected compounds. Two sets of passive samplers were also deployed to determine the influence of degradation during longer deployment times in passive sampling. In active air samplers, comparison of the two sampling configurations suggested degradation of particle-bound polycyclic aromatic hydrocarbons (PAHs), with concentrations up to 2× higher in the denuder-equipped sampler, while halogenated POPs did not have clear evidence of degradation. In contrast, more polar, reactive compounds (e.g., organophosphate esters and current use pesticides) had evidence of losses in the sampler with denuder. This may be caused by the denuder itself, suggesting sampling bias for these compounds can be created when typical air sampling apparatuses are adapted to limit degradation. Passive air samplers recorded up to 4× higher concentrations when deployed for shorter consecutive sampling periods, suggesting that within-sampler degradation may also be relevant in passive air monitoring programs.

  18. Dust acoustic shock wave at high dust density

    International Nuclear Information System (INIS)

    Ghosh, Samiran; Sarkar, Susmita; Khan, Manoranjan; Avinash, K.; Gupta, M. R.

    2003-01-01

    Dust acoustic (DA) shock wave at high dust density, i.e., the dust electroacoustic (DEA) or dust Coulomb (DC) shock wave has been investigated incorporating the nonadiabatic dust charge variation. The nonlinear DEA (DC) shock wave is seen to be governed by the Korteweg-de Vries Burger equation, in which the Burger term is proportional to the nonadiabaticity generated dissipation. It is seen that the shock strength decreases but after reaching minimum, it increases as the dust space charge density |q d n d | increases and the shock strength of DA wave is greater than that of DEA (DC) wave. Moreover the DEA (DC) shock width increases appreciably with increase mass m i of the ion component of the dusty plasma but for DA shock wave the effect is weak

  19. Dust, Climate, and Human Health

    Science.gov (United States)

    Maynard, Nancy G.

    2003-01-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. This paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

  20. Parameterizing the interstellar dust temperature

    Science.gov (United States)

    Hocuk, S.; Szűcs, L.; Caselli, P.; Cazaux, S.; Spaans, M.; Esplugues, G. B.

    2017-08-01

    The temperature of interstellar dust particles is of great importance to astronomers. It plays a crucial role in the thermodynamics of interstellar clouds, because of the gas-dust collisional coupling. It is also a key parameter in astrochemical studies that governs the rate at which molecules form on dust. In 3D (magneto)hydrodynamic simulations often a simple expression for the dust temperature is adopted, because of computational constraints, while astrochemical modelers tend to keep the dust temperature constant over a large range of parameter space. Our aim is to provide an easy-to-use parametric expression for the dust temperature as a function of visual extinction (AV) and to shed light on the critical dependencies of the dust temperature on the grain composition. We obtain an expression for the dust temperature by semi-analytically solving the dust thermal balance for different types of grains and compare to a collection of recent observational measurements. We also explore the effect of ices on the dust temperature. Our results show that a mixed carbonaceous-silicate type dust with a high carbon volume fraction matches the observations best. We find that ice formation allows the dust to be warmer by up to 15% at high optical depths (AV> 20 mag) in the interstellar medium. Our parametric expression for the dust temperature is presented as Td = [ 11 + 5.7 × tanh(0.61 - log 10(AV) ]χuv1/5.9, where χuv is in units of the Draine (1978, ApJS, 36, 595) UV field.

  1. Respiratory health effects and exposure to superabsorbent polymer and paper dust - an epidemiological study

    Directory of Open Access Journals (Sweden)

    Torén Kjell

    2011-07-01

    Full Text Available Abstract Background The primary aim of the present study was to investigate if exposure to dust from absorbent hygiene products containing superabsorbent polymer is related to symptoms from the airways and from the eyes. The secondary aim was to estimate the current exposure to superabsorbent polymer among production and maintenance workers in a plant producing hygiene products. Methods The cohort comprised 1043 workers of whom 689 were exposed to super absorbent polymer and 804 were exposed to paper dust (overlapping groups. There was 186 workers not exposed to either superabsorbent polymer or to paper dust They were investigated with a comprehensive questionnaire about exposure, asthma, rhinitis and symptoms from eyes and airways. The results were analyzed with logistic regression models adjusting for sex, age, atopy and smoking habits. An aerosol sampler equipped with a polytetrafluoroethylene filter with 1 μm pore size was used for personal samplings in order to measure inhalable dust and superabsorbent polymer. Results The prevalence of nasal crusts (OR 1.4, 95% CI 1.01-2.0 and nose-bleeding (OR 1.7, 95% CI 1.2-2.4 was increased among the paper dust exposed workers (adjusted for superabsorbent polymer exposure. There were no significant effects associated with exposure to superabsorbent polymer (adjusted for paper dust exposure. The average exposure to inhalable levels of total dust (paper dust varied between 0.40 and 1.37 mg/m3. For superabsorbent polymer dust the average exposure varied between 0.02 and 0.81 mg/m3. Conclusions In conclusion, our study shows that workers manufacturing diapers in the hygiene industry have an increased prevalence of symptoms from the nose, especially nose-bleeding. There was no relation between exposure to superabsorbent polymer and symptoms from eyes, nose or respiratory tract, but exposure to paper dust was associated with nose-bleeding and nasal crusts. This group of workers had also a considerable

  2. Comparative evaluation of three impactor samplers for measuring airborne bacteria and fungi concentrations.

    Science.gov (United States)

    Méheust, Delphine; Gangneux, Jean-Pierre; Cann, Pierre Le

    2013-01-01

    Portable microbial samplers are useful for detecting microorganisms in the air. However, limited data are available on their performance when sampling airborne biological agents in a routine practice. We compared bacterial and fungal concentrations obtained in field conditions using three impactor samplers with different designs (AES Chemunex Sampl'Air, bioMérieux Air Ideal, and Sartorius AirPort MD8/BACTair). The linearity of mold collection was tested in the range of 100 L to 1000 L, and all the devices had a correlation coefficient higher than 0.95. For optimal comparison of the samplers, we performed experiments in different hospital rooms with varying levels of air biocontamination. Each sampling procedure was repeated to assess reproducibility. No significant difference between the samplers was observed for the mold concentrations on Sabouraud agar, whereas Sampl'Air collected significantly more bacteria on tryptic soy agar than Air Ideal or BACTair at one of the sites. Impactor location in the room was nevertheless associated with the variability observed with the three samplers at the highest microbial concentration levels. On the basis of their performance, autonomy and simplicity of use, these three impactors are suitable for routine indoor evaluation of microbial air contamination.

  3. Chemical and toxicologic assessment of organic contaminants in surface water using passive samplers

    Science.gov (United States)

    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.

  4. HTO/HT discriminating samplers constructed for the french experiment on the environmental behaviour of HT

    International Nuclear Information System (INIS)

    Ogram, G.L.

    1988-12-01

    The French Experiment on Environmental Tritium Behaviour was a field experiment carried out to determine the rate of formation of atmospheric HTO from a release of HT to the natural environment. The Canadian Fusion Fuels Technology Project and Ontario Hydro contributed to the project by supplying HTO/HT-discriminating, atmospheric tritium samplers. Each sampler consisted of a molecular-sieve trap to capture HTO followed by a Pd-impregnated molecular-sieve trap to oxidise and collect HT from the same air stream. This method was selected as it provided high sensitivity over short sampling periods and was convenient for field use. Laboratory tests indicated that this system measured HT concentrations reliably, but only achieved limited discrimination between HT and HTO at HTO/HT concentration ratios below 10 -2 to 10 -3 . Small cold traps were therefore operated during the French experiment in addition to the molecular-sieve samplers exhibited much improved discrimination in the field (approaching 10 4 ), possibly due to higher sampling flow rates than used in the laboratory. These results demonstrate that care should be taken in using desiccant-based, HTO/HT-discriminating samplers when the HT concentration is much higher than HTO concentration, and suggest the need to systematically characterize and perhaps improve the performance of discriminating samplers at low HTO/HT ratios

  5. Evaluation of passive samplers for the collection of dissolved organic matter in streams.

    Science.gov (United States)

    Warner, Daniel L; Oviedo-Vargas, Diana; Royer, Todd V

    2015-01-01

    Traditional sampling methods for dissolved organic matter (DOM) in streams limit opportunities for long-term studies due to time and cost constraints. Passive DOM samplers were constructed following a design proposed previously which utilizes diethylaminoethyl (DEAE) cellulose as a sampling medium, and they were deployed throughout a temperate stream network in Indiana. Two deployments of the passive samplers were conducted, during which grab samples were frequently collected for comparison. Differences in DOM quality between sites and sampling methods were assessed using several common optical analyses. The analyses revealed significant differences in optical properties between sampling methods, with the passive samplers preferentially collecting terrestrial, humic-like DOM. We assert that the differences in DOM composition from each sampling method were caused by preferential binding of complex humic compounds to the DEAE cellulose in the passive samplers. Nonetheless, the passive samplers may provide a cost-effective, integrated sample of DOM in situations where the bulk DOM pool is composed mainly of terrestrial, humic-like compounds.

  6. Detecting dust hits at Enceladus, Saturn and beyond using CAPS / ELS data from Cassini

    Science.gov (United States)

    Vandegriff, J. D.; Stoneberger, P. J.; Jones, G.; Waite, J. H., Jr.

    2016-12-01

    It has recently been shown (1) that the impact of hypervelocity dust grains on the Cassini spacecraft can be detected by the Cassini Plasma Spectrometer (CAPS) Electron Spectrometer (ELS) instrument. For multiple Enceladus flybys, fine scale features in the lower energy regime of ELS energy spectra can be explained as short-duration, isotropic plasma clouds due to dust impacts. We have developed an algorithm for detecting these hypervelocity dust impacts, and the list of such impacts during Enceladus flybys will be presented. We also present preliminary results obtained when using the algorithm to search for dust impacts in other regions of Saturn's magnetosphere as well as in the solar wind. (1) Jones, Geraint, Hypervelocity dust impact signatures detected by Cassini CAPS-ELS in the Enceladus plume, MOP Meeting, June 1-5, 2015, Atlanta, GA

  7. Dust in H II regions

    International Nuclear Information System (INIS)

    Isobe, S.

    1977-01-01

    Several pieces of evidence indicate that H II regions may contain dust: 1) the continuum light scattered by dust grains (O'Dell and Hubbard, 1965), 2) thermal radiation from dust grains at infrared wavelengths (Ney and Allen, 1969), 3) the abnormal helium abundance in some H II regions (Peimbert and Costero, 1969), etc. Although observations of the scattered continuum suggest that the H II region cores may be dust-free, dust grains and gas must be well mixed in view of the infrared observations. This difficulty may be solved by introducing globules with sizes approximately 0.001 pc. These globules and the molecular clouds adjacent to H II regions are the main sources supplying dust to H II regions. (Auth.)

  8. Large Aperture Electrostatic Dust Detector

    International Nuclear Information System (INIS)

    Skinner, C.H.; Hensley, R.; Roquemore, A.L.

    2007-01-01

    Diagnosis and management of dust inventories generated in next-step magnetic fusion devices is necessary for their safe operation. A novel electrostatic dust detector, based on a fine grid of interlocking circuit traces biased to 30 or 50 v has been developed for the detection of dust particles on remote surfaces in air and vacuum environments. Impinging dust particles create a temporary short circuit and the resulting current pulse is recorded by counting electronics. Up to 90% of the particles are ejected from the grid or vaporized suggesting the device may be useful for controlling dust inventories. We report measurements of the sensitivity of a large area (5x5 cm) detector to microgram quantities of dust particles and review its applications to contemporary tokamaks and ITER.

  9. Update on Automated Classification of Interplanetary Dust Particles

    Science.gov (United States)

    Maroger, I.; Lasue, J.; Zolensky, M.

    2018-01-01

    Every year, the Earth accretes about 40,000 tons of extraterrestrial material less than 1 mm in size on its surface. These dust particles originate from active comets, from impacts between asteroids and may also be coming from interstellar space for the very small particles. Since 1981, NASA Jonhson Space Center (JSC) has been systematically collecting the dust from Earth's strastosphere by airborne collectors and gathered them into "Cosmic Dust Catalogs". In those catalogs, a preliminary analysis of the dust particles based on SEM images, some geological characteristics and X-ray energy-dispersive spectrometry (EDS) composition is compiled. Based on those properties, the IDPs are classified into four main groups: C (Cosmic), TCN (Natural Terrestrial Contaminant), TCA (Artificial Terrestrial Contaminant) and AOS (Aluminium Oxide Sphere). Nevertheless, 20% of those particles remain ambiguously classified. Lasue et al. presented a methodology to help automatically classify the particles published in the catalog 15 based on their EDS spectra and nonlinear multivariate projections (as shown in Fig. 1). This work allowed to relabel 155 particles out of the 467 particles in catalog 15 and reclassify some contaminants as potential cosmic dusts. Further analyses of three such particles indicated their probable cosmic origin. The current work aims to bring complementary information to the automatic classification of IDPs to improve identification criteria.

  10. Photoelectric charging of dust grains

    International Nuclear Information System (INIS)

    Ignatov, A. M.

    2009-01-01

    Photoemission from the surface of a dust grain in vacuum is considered. It is shown that the cutoff in the energy spectrum of emitted electrons leads to the formation of a steady-state electron cloud. The equation describing the distribution of the electric potential in the vicinity of a dust grain is solved numerically. The dust grain charge is found as a function of the grain size.

  11. Dust in cosmic plasma environments

    International Nuclear Information System (INIS)

    Mendis, D.A.

    1979-01-01

    Cosmic dust is invariably immersed in a plasma and a radiative environment. Consequently, it is charged to some electrostatic potential which depends on the properties of the environment as well as the nature of the dust. This charging affects the physical and dynamical properties of the dust. In this paper the basic aspects of this dust-plasma interaction in several cosmic environments - including planetary magnetospheres, the heliosphere and the interstellar medium - are discussed. The physical and dynamical consequences of the interaction, as well as the pertinent observational evidence, are reviewed. Finally, the importance of the surface charge during the condensation process in plasma environments is stressed. (Auth.)

  12. Short-term diffusive sampler for nitrogen dioxide monitoring in epidemiology

    International Nuclear Information System (INIS)

    Michaud, J.P.; Quackenboss, J.

    1991-01-01

    An automated timed exposure diffusive sampler (TEDS) for sampling nitrogen dioxide (NO 2 ) was developed for use in epidemiological studies. The TEDS sequentially exposes four passive sampling devices (PSD) by microprocessor controlled valves while a pump and air flow guide prevent sampler starvation. Two TEDS units and two portable, real-time NO 2 monitors were tested for accuracy, precision, sensitivity, and linearity of response. The accuracy of the TEDS was within 10 percent of the means of the measured values. The TEDS sensitivity was 20 to 30 ppb-hour for NO 2 . Co-location of the TEDS with a chemiluminescent NO x monitor (EPA reference method) showed a similar responses to ambient NO 2 . TEDS allows better time resolution than traditional diffusive samplers (i.e., Palmes tube) while sharing their ability to sample a variety of gases

  13. Bayesian analysis for exponential random graph models using the adaptive exchange sampler

    KAUST Repository

    Jin, Ick Hoon

    2013-01-01

    Exponential random graph models have been widely used in social network analysis. However, these models are extremely difficult to handle from a statistical viewpoint, because of the existence of intractable normalizing constants. In this paper, we consider a fully Bayesian analysis for exponential random graph models using the adaptive exchange sampler, which solves the issue of intractable normalizing constants encountered in Markov chain Monte Carlo (MCMC) simulations. The adaptive exchange sampler can be viewed as a MCMC extension of the exchange algorithm, and it generates auxiliary networks via an importance sampling procedure from an auxiliary Markov chain running in parallel. The convergence of this algorithm is established under mild conditions. The adaptive exchange sampler is illustrated using a few social networks, including the Florentine business network, molecule synthetic network, and dolphins network. The results indicate that the adaptive exchange algorithm can produce more accurate estimates than approximate exchange algorithms, while maintaining the same computational efficiency.

  14. Passive Sampler for Measurements of Atmospheric Nitric Acid Vapor (HNO3 Concentrations

    Directory of Open Access Journals (Sweden)

    Andrzej Bytnerowicz

    2001-01-01

    Full Text Available 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.

  15. A novel enhanced diffusion sampler for collecting gaseous pollutants without air agitation.

    Science.gov (United States)

    Pan, Xuelian; Zhuo, Shaojie; Zhong, Qirui; Chen, Yuanchen; Du, Wei; Cheng, Hefa; Wang, Xilong; Zeng, Eddy Y; Xing, Baoshan; Tao, Shu

    2018-03-06

    A novel enhanced diffusion sampler for collecting gaseous phase polycyclic aromatic hydrocarbons (PAHs) without air agitation is proposed. The diffusion of target compounds into a sampling chamber is facilitated by continuously purging through a closed-loop flow to create a large concentration difference between the ambient air and the air in the sampling chamber. A glass-fiber filter-based prototype was developed. It was demonstrated that the device could collect gaseous PAHs at a much higher rate (1.6 ± 1.4 L/min) than regular passive samplers, while the ambient air is not agitated. The prototype was also tested in both the laboratory and field for characterizing the concentration gradients over a short distance from the soil surface. The sampler has potential to be applied in other similar situations to characterize the concentration profiles of other chemicals.

  16. COMPARISON OF THE PARTICLE SIZE DISTRIBUTION OF HEAVY-DUTY DIESEL EXHAUST USING A DILUTION TAIL-PIPE SAMPLER AND IN-PLUME SAMPLER DURING ON-ROAD OPERATION

    Science.gov (United States)

    The paper compares the particle size distribution of heavy-duty diesel exhaust using a dilution tail-pipe sampler and an in-plume sampler during on-road operation. EPA's On-road Diesel Emissions Characterization Facility, modified to incorporate particle measurement instrumentat...

  17. Composite sampling of a Bacillus anthracis surrogate with cellulose sponge surface samplers from a nonporous surface.

    Directory of Open Access Journals (Sweden)

    Jenia A M Tufts

    Full Text Available A series of experiments was conducted to explore the utility of composite-based collection of surface samples for the detection of a Bacillus anthracis surrogate using cellulose sponge samplers on a nonporous stainless steel surface. Two composite-based collection approaches were evaluated over a surface area of 3716 cm2 (four separate 929 cm2 areas, larger than the 645 cm2 prescribed by the standard Centers for Disease Control (CDC and Prevention cellulose sponge sampling protocol for use on nonporous surfaces. The CDC method was also compared to a modified protocol where only one surface of the sponge sampler was used for each of the four areas composited. Differences in collection efficiency compared to positive controls and the potential for contaminant transfer for each protocol were assessed. The impact of the loss of wetting buffer from the sponge sampler onto additional surface areas sampled was evaluated. Statistical tests of the results using ANOVA indicate that the collection of composite samples using the modified sampling protocol is comparable to the collection of composite samples using the standard CDC protocol (p  =  0.261. Most of the surface-bound spores are collected on the first sampling pass, suggesting that multiple passes with the sponge sampler over the same surface may be unnecessary. The effect of moisture loss from the sponge sampler on collection efficiency was not significant (p  =  0.720 for both methods. Contaminant transfer occurs with both sampling protocols, but the magnitude of transfer is significantly greater when using the standard protocol than when the modified protocol is used (p<0.001. The results of this study suggest that composite surface sampling, by either method presented here, could successfully be used to increase the surface area sampled per sponge sampler, resulting in reduced sampling times in the field and decreased laboratory processing cost and turn-around times.

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

    Science.gov (United States)

    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.

  19. Microfluidic Air Sampler for Highly Efficient Bacterial Aerosol Collection and Identification.

    Science.gov (United States)

    Bian, Xiaojun; Lan, Ying; Wang, Bing; Zhang, Yu Shrike; Liu, Baohong; Yang, Pengyuan; Zhang, Weijia; Qiao, Liang

    2016-12-06

    The early warning capability of the presence of biological aerosol threats is an urgent demand in ensuing civilian and military safety. Efficient and rapid air sample collection in relevant indoor or outdoor environment is a key step for subsequent analysis of airborne microorganisms. Herein, we report a portable battery-powered sampler that is capable of highly efficient bioaerosol collection. The essential module of the sampler is a polydimethylsiloxane (PDMS) microfluidic chip, which consisted of a 3-loop double-spiral microchannel featuring embedded herringbone and sawtooth wave-shaped structures. Vibrio parahemolyticus (V. parahemolyticus) as a model microorganism, was initially employed to validate the bioaerosol collection performance of the device. Results showed that the sampling efficacy reached as high as >99.9%. The microfluidic sampler showed greatly improved capturing efficiency compared with traditional plate sedimentation methods. The high performance of our device was attributed to the horizontal inertial centrifugal force and the vertical turbulence applied to airflow during sampling. The centrifugation field and turbulence were generated by the specially designed herringbone structures when air circulated in the double-spiral microchannel. The sawtooth wave-shaped microstructure created larger specific surface area for accommodating more aerosols. Furthermore, a mixture of bacterial aerosols formed by V. parahemolyticus, Listeria monocytogenes, and Escherichia coli was extracted by the microfluidic sampler. Subsequent integration with mass spectrometry conveniently identified the multiple bacterial species captured by the sampler. Our developed stand-alone and cable-free sampler shows clear advantages comparing with conventional strategies, including portability, easy-to-use, and low cost, indicating great potential in future field applications.

  20. Gravitational radiation from dust

    International Nuclear Information System (INIS)

    Isaacson, R.A.; Welling, J.S.; Winicour, J.

    1985-01-01

    A dust cloud is examined within the framework of the general relativistic characteristic initial value problem. Unique gravitational initial data are obtained by requiring that the space-time be quasi-Newtonian. Explicit calculations of metric and matter fields are presented, which include all post-Newtonian corrections necessary to discuss the major physical properties of null infinity. These results establish a curved space version of the Einstein quadrupole formula, in the form ''news function equals third time derivative of transverse quadrupole moment,'' for this system. However, these results imply that some weakened notion of asymptotic flatness is necessary for the description of quasi-Newtonian systems

  1. Dust coagulation in ISM

    Science.gov (United States)

    Chokshi, Arati; Tielens, Alexander G. G. M.; Hollenbach, David

    1989-01-01

    Coagulation is an important mechanism in the growth of interstellar and interplanetary dust particles. The microphysics of the coagulation process was theoretically analyzed as a function of the physical properties of the coagulating grains, i.e., their size, relative velocities, temperature, elastic properties, and the van der Waal interaction. Numerical calculations of collisions between linear chains provide the wave energy in individual particles and the spectrum of the mechanical vibrations set up in colliding particles. Sticking probabilities are then calculated using simple estimates for elastic deformation energies and for the attenuation of the wave energy due to absorption and scattering processes.

  2. Adapting MODIS Dust Mask Algorithm to Suomi NPP VIIRS for Air Quality Applications

    Science.gov (United States)

    Ciren, P.; Liu, H.; Kondragunta, S.; Laszlo, I.

    2012-12-01

    Despite pollution reduction control strategies enforced by the Environmental Protection Agency (EPA), large regions of the United States are often under exceptional events such as biomass burning and dust outbreaks that lead to non-attainment of particulate matter standards. This has warranted the National Weather Service (NWS) to provide smoke and dust forecast guidance to the general public. The monitoring and forecasting of dust outbreaks relies on satellite data. Currently, Aqua/MODIS (MODerate resolution Imaging Spectrometer) and Terra/MODIS provide measurements needed to derive dust mask and Aerosol Optical Thickness (AOT) products. The newly launched Suomi NPP VIIRS (Visible/Infrared Imaging Radiometer Suite) instrument has a Suspended Matter (SM) product that indicates the presence of dust, smoke, volcanic ash, sea salt, and unknown aerosol types in a given pixel. The algorithm to identify dust is different over land and ocean but for both, the information comes from AOT retrieval algorithm. Over land, the selection of dust aerosol model in the AOT retrieval algorithm indicates the presence of dust and over ocean a fine mode fraction smaller than 20% indicates dust. Preliminary comparisons of VIIRS SM to CALIPSO Vertical Feature Mask (VFM) aerosol type product indicate that the Probability of Detection (POD) is at ~10% and the product is not mature for operational use. As an alternate approach, NESDIS dust mask algorithm developed for NWS dust forecast verification that uses MODIS deep blue, visible, and mid-IR channels using spectral differencing techniques and spatial variability tests was applied to VIIRS radiances. This algorithm relies on the spectral contrast of dust absorption at 412 and 440 nm and an increase in reflectivity at 2.13 μm when dust is present in the atmosphere compared to a clear sky. To avoid detecting bright desert surface as airborne dust, the algorithm uses the reflectances at 1.24 μm and 2.25 μm to flag bright pixels. The

  3. Dust confinement and dust acoustic waves in a magnetized plasma

    Science.gov (United States)

    Piel, A.

    2005-10-01

    Systematic laboratory experiments on dust acoustic waves require the confinement of dust particles. Here we report on new experiments in a magnetized plasma region in front of an additional positively biased disk electrode in a background plasma which is generated in argon at 27MHz between a disk and grid electrode. The plasma diffuses through the grid along the magnetic field. The three-dimensional dust distribution is measured with a horizontal sheet of laser light and a CCD camera, which are mounted on a vertical translation stage. Depending on magnetic field and discharge current, cigar or donut-shaped dust clouds are generated, which tend to rotate about the magnetic field direction. Measurements with emissive probes show that the axial confinement of dust particles with diameters between 0.7-2 μm is achieved by a balance of ion-drag force and electric field force. Dust levitation and radial confinement is due to a strong radial electric field. Dust acoustic waves are destabilized by the ion flow or can be stimulated by a periodic bias on the disk electrode. The observed wave dispersion is compared with fluid and kinetic models of the dust acoustic wave.

  4. Gravimetric dust sampling for control purposes and occupational dust sampling.

    CSIR Research Space (South Africa)

    Unsted, AD

    1997-02-01

    Full Text Available Prior to the introduction of gravimetric dust sampling, konimeters had been used for dust sampling, which was largely for control purposes. Whether or not absolute results were achievable was not an issue since relative results were used to evaluate...

  5. The determination of volatile chlorinated hydrocarbons in air. Sampling rate and efficiency of diffuse samplers

    Energy Technology Data Exchange (ETDEWEB)

    Giese, U.; Stenner, H.; Kettrup, A.

    1989-05-01

    When applicating diffusive sampling-systems to workplace air-monitoring it is necessary to know the behaviour of the diffusive-rate and the efficiency in dependence of concentration, exposition time and the type of pollutant. Especially concerning mixtures of pollutants there are negative influences by competition and mutual displacement possible. Diffusive-rate and discovery for CH/sub 2/Cl/sub 2/ and CHCl/sub 3/ were investigated using two different types of diffuse samplers. For this it was necessary to develop suitable defices for standard gas generation and for the exposition of diffusive-samplers to a standard gas mixture. (orig.).

  6. Task QA plan for Modified Prototypic Hydragard trademark Sampler Overflow System Demonstration at TNX

    International Nuclear Information System (INIS)

    Snyder, T.K.

    1993-01-01

    The primary objective of this task is to evaluate the proposed design modifications to the sample system, including the adequacy of the recommended eductor and the quality of samples obtained from the modified system. Presently, the sample streams are circulated from the originating tank, through a Hydragard trademark sampler system, and back to the originating tank. The overflow from the Hydragard trademark sampler flows to the Recycle Collection Tank (RCT). This report outlines the planned quality assurance controls for the design modification task, including organization and personnel, surveillances, and records package

  7. Of data and dust

    CERN Multimedia

    Stephanie Hills

    2016-01-01

    The traditional image of an archive is one of dusty old boxes, books and papers. When your archive is digital, dust spells disaster. An innovative environmental sensor designed and built by a CERN IT specialist has become an essential element in the Laboratory’s data-preservation strategy.   The novel air particle monitoring sensor designed by CERN's Julien Leduc. CERN’s archive holds more than 130 petabytes of data from past and present high-energy physics experiments. Some of it is 40 years old, most of it needs to be kept forever, and all of it is held on tape cartridges (over 20,000 of them). The cartridges are held inside tape libraries with robotic arms that load them into tape drives where they can be read and written. Tape cartridges have many advantages over other data storage media, notably cost and long-term reliability, but topping the list of drawbacks is their vulnerability to contamination from airborne dust particles; a tiny piece of g...

  8. Radionuclides in house dust

    Energy Technology Data Exchange (ETDEWEB)

    Fry, F A; Green, N; Dodd, N J; Hammond, D J

    1985-04-01

    Discharges of radionuclides from the British Nuclear Fuel plc (BNFL) reprocessing plant at Sellafield in Cumbria have led to elevated concentrations radionuclides in the local environment. The major routes of exposure of the public are kept under review by the appropriate authorising Government departments and monitoring is carried out both by the departments and by BNFL itself. Recently, there has been increasing public concern about general environmental contamination resulting from the discharges and, in particular, about possible exposure of members of the public by routes not previously investigated in detail. One such postulated route of exposure that has attracted the interest of the public, the press and Parliament arises from the presence of radionuclides within houses. In view of this obvious and widespread concern, the Board has undertaken a sampling programme in a few communities in Cumbria to assess the radiological significance of this source of exposure. From the results of our study, we conclude that, although radionuclides originating rom the BNFL site can be detected in house dust, this source of contamination is a negligible route of exposure for members of the public in West Cumbria. This report presents the results of the Board's study of house dust in twenty homes in Cumbria during the spring and summer of 1984. A more intensive investigation is being carried out by Imperial College. (author)

  9. Health hazards of cement dust

    International Nuclear Information System (INIS)

    Meo, Sultan A.

    2004-01-01

    ven in the 21st century, millions of people are working daily in a dusty environment. They are exposed to different types of health hazards such as fume, gases and dust, which are risk factors in developing occupational disease. Cement industry is involved in the development of structure of this advanced and modern world but generates dust during its production. Cement dust causes lung function impairment, chronic obstructive lung disease, restrictive lung disease, pneumoconiosis and carcinoma of the lungs, stomach and colon. Other studies have shown that cement dust may enter into the systemic circulation and thereby reach the essentially all the organs of body and affects the different tissues including heart, liver, spleen, bone, muscles and hairs and ultimately affecting their micro-structure and physiological performance. Most of the studies have been previously attempted to evaluate the effects of cement dust exposure on the basis of spirometry or radiology, or both. However, collective effort describing the general effects of cement dust on different organ and systems in humans or animals, or both has not been published. Therefore, the aim of this review is to gather the potential toxic effects of cement dust and to minimize the health risks in cement mill workers by providing them with information regarding the hazards of cement dust. (author)

  10. Dust forecasting system in JMA

    International Nuclear Information System (INIS)

    Mikami, M; Tanaka, T Y; Maki, T

    2009-01-01

    JMAs dust forecasting information, which is based on a GCM dust model, is presented through the JMA website coupled with nowcast information. The website was updated recently and JMA and MOE joint 'KOSA' website was open from April 2008. Data assimilation technique will be introduced for improvement of the 'KOSA' information.

  11. Dust in flowing magnetized plasma

    International Nuclear Information System (INIS)

    Pandey, Birendra P.; Samarian, Alex A.; Vladimirov, Sergey V.

    2009-01-01

    Plasma flows occur in almost every laboratory device and interactions of flowing plasmas with near-wall impurities and/or dust significantly affects the efficiency and lifetime of such devices. The charged dust inside the magnetized flowing plasma moves primarily under the influence of the plasma drag and electric forces. Here, the charge on the dust, plasma potential, and plasma density are calculated self-consistently. The electrons are assumed non-Boltzmannian and the effect of electron magnetization and electron-atom collisions on the dust charge is calculated in a self-consistent fashion. For various plasma magnetization parameters viz. the ratio of the electron and ion cyclotron frequencies to their respective collision frequencies, plasma-atom and ionization frequencies, the evolution of the plasma potential and density in the flow region is investigated. The variation of the dust charge profile is shown to be a sensitive function of plasma parameters. (author)

  12. Dust in protoplanetary disks: observations*

    Directory of Open Access Journals (Sweden)

    Waters L.B.F.M.

    2015-01-01

    Full Text Available Solid particles, usually referred to as dust, are a crucial component of interstellar matter and of planet forming disks surrounding young stars. Despite the relatively small mass fraction of ≈1% (in the solar neighborhood of our galaxy; this number may differ substantially in other galaxies that interstellar grains represent of the total mass budget of interstellar matter, dust grains play an important role in the physics and chemistry of interstellar matter. This is because of the opacity dust grains at short (optical, UV wavelengths, and the surface they provide for chemical reactions. In addition, dust grains play a pivotal role in the planet formation process: in the core accretion model of planet formation, the growth of dust grains from the microscopic size range to large, cm-sized or larger grains is the first step in planet formation. Not only the grain size distribution is affected by planet formation. Chemical and physical processes alter the structure and chemical composition of dust grains as they enter the protoplanetary disk and move closer to the forming star. Therefore, a lot can be learned about the way stars and planets are formed by observations of dust in protoplanetary disks. Ideally, one would like to measure the dust mass, the grain size distribution, grain structure (porosity, fluffiness, the chemical composition, and all of these as a function of position in the disk. Fortunately, several observational diagnostics are available to derive constrains on these quantities. In combination with rapidly increasing quality of the data (spatial and spectral resolution, a lot of progress has been made in our understanding of dust evolution in protoplanetary disks. An excellent review of dust evolution in protoplanetary disks can be found in Testi et al. (2014.

  13. COAL DUST EMISSION PROBLEM

    Directory of Open Access Journals (Sweden)

    M. M. Biliaiev

    2016-12-01

    Full Text Available Purpose. The article aims to develop 2D numerical models for the prediction of atmospheric pollution during transportation of coal in the railway car, as well as the ways to protect the environment and the areas near to the mainline from the dust emission due to the air injection installation. Methodology. To solve this problem there were developed numerical models based on the use of the equations of motion of an inviscid incompressible fluid and mass transfer. For the numerical integration of the transport equation of the pollutant the implicit alternating-triangular difference scheme was used. For numerical integration of the 2D equation for the velocity potential the method of total approximation was used. The developed numerical models are the basis of established software package. On the basis of the constructed numerical models it was carried out a computational experiment to assess the level of air pollution when transporting bulk cargo by rail when the railway car has the air injection. Findings. 2D numerical models that belong to the class «diagnostic models» were developed. These models take into account the main physical factors affecting the process of dispersion of dust pollution in the atmosphere during transportation of bulk cargo. The developed numerical models make it possible to calculate the dust loss process, taking into account the use of the air injection of the car. They require a small cost of the computer time during practical realization at the low and medium power machines. There were submitted computational calculations to determine pollutant concentrations and the formation of the zone of pollution near the train with bulk cargo in «microscale» scale taking into account the air curtains. Originality. 2D numerical models taking into account the relevant factors influencing the process of dispersion of pollutants in the atmosphere, and the formation of the zone of pollution during transportation of bulk cargo by

  14. EVALUATION OF MEMBRANE TYPE FOR USE IN DIFFUSION SAMPLERS TO MONITOR GROUND WATER QUALITY

    Science.gov (United States)

    The Discrete Multi-Level Sampler (DMLS®) system has proven to be a useful tool for obtaining discrete interval contaminant concentrations at hazardous waste sites. The DMLS® utilizes dialysis cells, which consist of a polypropylene vial, covered on both ends by a permeable membr...

  15. 7 CFR 61.33 - Equipment of sampler; contents of certificate.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Equipment of sampler; contents of certificate. 61.33 Section 61.33 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS...

  16. Mechanical reliability evaluation of alternate motors for use in a radioiodine air sampler

    International Nuclear Information System (INIS)

    Bird, S.K.; Huchton, R.L.; Motes, B.G.

    1984-03-01

    Detailed mechanical reliability studies of two alternate motors identified for use in the BNL Air Sampler wer conducted. The two motor types were obtained from Minnesota Electric Technology, Incorporated (MET) and TCS Industries (TCSI). Planned testing included evaluation of motor lifetimes and motor operability under different conditions of temperature, relative humidity, simulated rainfall, and dusty air. The TCSI motors were not lifetime tested due to their poor performance during the temperature/relative humidity tests. While operation on alternating current was satisfactory, on direct current only one of five TCSI motors completed all environmental testing. The MET motors had average lifetimes of 47 hours, 97 hours, and 188 hours, respectively, and exhibited satisfactory operation under all environmental test conditions. Therefore, the MET motor appears to be the better candidate motor for use in the BNL Air Sampler. However, because of the relatively high cost of purchasing and incorporating the MET motor into the BNL Air Sampler System, it is recommended that commercial air sampler systems be evaluated for use instead of the BNL system

  17. Evaluation of a depth proportional intake device for automatic pumping samplers

    Science.gov (United States)

    Rand E. Eads; Robert B. Thomas

    1983-01-01

    Abstract - A depth proportional intake boom for portable pumping samplers was used to collect suspended sediment samples in two coastal streams for three winters. The boom pivots on the stream bed while a float on the downstream end allows debris to depress the boom and pass without becoming trapped. This equipment modifies point sampling by maintaining the intake...

  18. Unified Frequency-Domain Analysis of Switched-Series-RC Passive Mixers and Samplers

    NARCIS (Netherlands)

    Soer, M.C.M.; Klumperink, Eric A.M.; de Boer, Pieter-Tjerk; van Vliet, Frank Edward; Nauta, Bram

    2010-01-01

    Abstract—A wide variety of voltage mixers and samplers are implemented with similar circuits employing switches, resistors, and capacitors. Restrictions on duty cycle, bandwidth, or output frequency are commonly used to obtain an analytical expression for the response of these circuits. This paper

  19. Development of floor smear sampler (floor radioactive contamination measuring instrument) for nuclear facilities

    International Nuclear Information System (INIS)

    Miyagawa, Minoru; Ito, Haruo; Nozawa, Katsuro; Shinohara, Yotaro; Hashimoto, Hiroshi.

    1980-01-01

    The control of the floor contamination with radioactive substances in nuclear facilities is strictly carried out by smear method, in which the contaminants on floor surfaces are wiped off with filter papers or cloths, and the contamination density on the floor surfaces is measured through their intensity of radioactivity. This wiping work is laborious since it is carried out in leaning-over posture when many samples must be taken in wide floor area. Therefore, to achieve labor saving in this work, an automatic sampler was developed. In the floor smear sampler developed, samples are taken on long band type wiping cloths only by handle operation, and the sample numbers are printed. When many samples are taken in wide floor area, this is especially effective, and the labor saving by 1/3 to 1/2 can be achieved. At present, this sampler is put in practical use in Hamaoka Nuclear Power Station. At the time of trial manufacture, the method of wiping, the mechanisms of wiping, cloth feeding and running, the contact pressure and the number of times of wiping affecting wiping efficiency and the required torque of a motor were examined. The developed sampler is that of constant contact pressure, vibration wiping type, and the rate of sampling is 10 sec per one sample. 100 samples can be taken on one roll of wiping cloth. The results of performance test are reported. (Kako, I.)

  20. The use of passive samplers for monitoring polycyclic aromatic hydrocarbons in ambient air

    International Nuclear Information System (INIS)

    Jacob, J.; Grimmer, G.; Hildebrandt, A.

    1993-01-01

    In this study polycyclic aromatic hydrocarbon (PAH) concentrations of ambient air are compared to those present in leaves, spruce sprouts and in the corresponding soil used as passive samplers. Marked profile alterations were detected in various soil horizons with increasing relative concentrations of higher boiling and decreasing relative concentrations of lower boiling PAH with depth. There is no direct correlation between the absolute PAH masses found in air samples and those collected by passive samplers or detected in corresponding soil samples. Even the PAH profiles differ significantly: they can, however, be correlated by introducing PAH - and sampler-specific factors. The PAH profiles appear to indicate that coal combustion mostly contributes to the PAH air pollution in the FRG. The time course of the concentration of benzo(a)pyrene and benzo(e)pyrene during the past seven years as measured with spruce sprouts as biological passive sampler indicate a significant decrease of the PAH concentration (by a factor of two) in the FRG. First measurements in a clean air area of the Eastern part of the FRG exhibited up to ten times higher PAH concentrations than found in comparable areas of the western part of the country

  1. Water sampling at the Berge Helene FPSO at Chinguetti field in Mauritania using passive samplers

    NARCIS (Netherlands)

    Korytar, P.; Galien, van der W.

    2007-01-01

    Three rounds of water sampling were performed at the Berge Helene FPSO at the Chinguetti field in Mauritania using passive samplers attached to the FPSO to determine the levels of contamination that could potentially accumulate in organisms. Two rounds were carried out prior to the commencement of

  2. Design and experimental evaluation of a new nanoparticle thermophoretic personal sampler

    Energy Technology Data Exchange (ETDEWEB)

    Azong-Wara, Nkwenti; Asbach, Christof, E-mail: asbach@iuta.de; Stahlmecke, Burkhard; Fissan, Heinz; Kaminski, Heinz [Institute of Energy and Environmental Technology (IUTA), Air Quality and Sustainable Nanotechnology Unit (Germany); Plitzko, Sabine [Federal Institute for Occupational Safety and Health (BAuA) (Germany); Bathen, Dieter; Kuhlbusch, Thomas A. J. [Institute of Energy and Environmental Technology (IUTA), Air Quality and Sustainable Nanotechnology Unit (Germany)

    2013-04-15

    A personal sampler that thermophoretically samples particles between a few nanometers and approximately 300 nm has been designed and first prototypes built. The thermal precipitator (TP) is designed to take samples in the breathing zone of a worker in order to determine the personal exposure to airborne nanomaterials. In the sampler, particles are deposited onto silicon substrates that can be used for consecutive electron microscopic (EM) analysis of the particle size distribution and chemical composition of the sampled particles. Due to very homogeneous size-independent particle deposition on a large portion of the substrate, representative samples can be taken for offline analysis. The experimental evaluation revealed a good general agreement with numerical simulations concerning homogeneity of the deposit and a very high correlation (R Superscript-Two = 0.98) of the deposition rate per unit area with number concentrations simultaneously measured with an SMPS for particle sizes between 14 and 305 nm. The samplers' small size of only 45 x 32 Multiplication-Sign 97 mm{sup 3} and low weight of only 140 g make it perfectly suitable as a personal sampler. The power consumption for temperature control and pump is around 1.5 W and can be easily provided by batteries.

  3. Comparative performance of two air samplers for monitoring airborne fungal propagules

    Directory of Open Access Journals (Sweden)

    L.G.F. Távora

    2003-05-01

    Full Text Available Many studies have attempted to evaluate the importance of airborne fungi in the development of invasive fungal infection, especially for immunocompromised hosts. Several kinds of instruments are available to quantitate fungal propagule levels in air. We compared the performance of the most frequently used air sampler, the Andersen sampler with six stages, with a portable one, the Reuter centrifugal sampler (RCS. A total of 84 samples were analyzed, 42 with each sampler. Twenty-eight different fungal genera were identified in samples analyzed with the Andersen instrument. In samples obtained with the RCS only seven different fungal genera were identified. The three most frequently isolated genera in samples analyzed with both devices were Penicillium, Aspergillus and Cladophialophora. In areas supplied with a high efficiency particulate air filter, fungal spore levels were usually lower when compared to areas without these filters. There was a significant correlation between total fungal propagule measurements taken with both devices on each sampling occasion (Pearson coefficient = 0.50. However, the Andersen device recovered a broader spectrum of fungi. We conclude that the RCS can be used for quantitative estimates of airborne microbiological concentrations. For qualitative studies, however, this device cannot be recommended.

  4. A survey of perfluoroalkyl sulfonamides in indoor and outdoor air using passive air samplers

    Energy Technology Data Exchange (ETDEWEB)

    Shoeib, M.; Harner, T. [Meteorological Service of Canada, Environment Canada (Canada); Wilford, B.; Jones, K. [Lancaster Univ. (United Kingdom). Environmental Science; Zhu, J. [Chemistry Research Division, Health Canada, Tunney' s Pasture, Ottawa (Canada)

    2004-09-15

    Perfluorooctane sulfonate (PFOS) has recently emerged as a priority environmental pollutant due to its widespread detection in biological samples from remote regions including the Arctic and the Mid-North Pacific Ocean. Because PFOS is fairly involatile, it is hypothesized that its occurrence in remote regions is the result of atmospheric transport of more volatile precursor compounds such as the perfluoroalkyl sulfonamides (PFASs). PFASs are used in variety of consumer products for water and oil resistance including surface treatments for fabric, upholstery, carpet, paper and leather. In a recent pilot study employing high volume air samples, indoor air concentrations of PFASs were approximately 100 times greater than outdoor levels. This is of significance because people typically spend about 90% of their time indoors 5 and this exposure may serve as an important uptake pathway. Indoor air also serves as a source of PFASs to the outside where PFASs are ultimately transported and distributed throughout the environment. The current study is intended to be a more comprehensive survey of indoor and outdoor air allowing more confident conclusions to be made. Passive air samplers comprised of polyurethane foam (PUF) disks were used. These are quiet, non-intrusive samplers that operate without the aid of a pump or electricity. Air movement delivers chemical to the sampler which has a high retention capacity for persistent organic pollutants (POPs). PUF disks samplers have been previously used successfully to monitor different classes of hydrophobic persistent organic pollutants POPs.

  5. Iowa Developed Energy Activity Sampler (IDEAS), Grades 7-12: Social Studies.

    Science.gov (United States)

    Simonis, Doris G.

    Described is the Social Studies component of the Iowa Developed Energy Activity Sampler (IDEAS), a multidisciplinary energy education program designed for infusion into the curriculum of grades seven through twelve. Aspects of the energy situation addressed in these lessons include resource finiteness, exponential growth, standard of living,…

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

    NARCIS (Netherlands)

    Hofschreuder, P.; Meulen, van der W.; Heeres, P.; Slanina, J.

    1999-01-01

    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

  7. Silicone passive equilibrium samplers as ‘chemometers’ in eels and sediments of a Swedish lake

    DEFF Research Database (Denmark)

    Jahnke, Annika; Mayer, Philipp; McLachlan, Michael S.

    2014-01-01

    Passive equilibrium samplers deployed in two or more media of a system and allowed to come to equilibrium can be viewed as ‘chemometers’ that reflect the difference in chemical activities of contaminants between the media. We applied silicone-based equilibrium samplers to measure relative chemica...... diagenesis and sorption to phytoplankton. The ‘chemometer’ approach has the potential to become a powerful tool to study the thermodynamic controls on persistent organic chemicals in the environment and should be extended to other environmental compartments.......Passive equilibrium samplers deployed in two or more media of a system and allowed to come to equilibrium can be viewed as ‘chemometers’ that reflect the difference in chemical activities of contaminants between the media. We applied silicone-based equilibrium samplers to measure relative chemical...... activities of seven ‘indicator’ polychlorinated biphenyls (PCBs) and hexachlorobenzene in eels and sediments from a Swedish lake. Chemical concentrations in eels and sediments were also measured using exhaustive extraction methods. Lipid-normalized concentrations in eels were higher than organic carbon...

  8. 7 CFR 801.5 - Tolerance for diverter-type mechanical samplers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Tolerance for diverter-type mechanical samplers. 801.5 Section 801.5 Agriculture Regulations of the Department of Agriculture (Continued) GRAIN INSPECTION... OFFICIAL PERFORMANCE REQUIREMENTS FOR GRAIN INSPECTION EQUIPMENT § 801.5 Tolerance for diverter-type...

  9. PERFORMANCE OF A NEW DIFFUSIVE SAMPLER FOR HG0 DETERMINATION IN THE TROPOSPHERE

    Science.gov (United States)

    Mercury behaves uniquely in the atmosphere due to its volatility and long lifetime. The existing methods for measuring atmospheric mercury are either expensive or labour intensive. The present paper presents a new measurement technique, the diffusive sampler, that is portable, in...

  10. Dust of dark energy

    International Nuclear Information System (INIS)

    Lim, Eugene A.; Sawicki, Ignacy; Vikman, Alexander

    2010-01-01

    We introduce a novel class of field theories where energy always flows along timelike geodesics, mimicking in that respect dust, yet which possess non-zero pressure. This theory comprises two scalar fields, one of which is a Lagrange multiplier enforcing a constraint between the other's field value and derivative. We show that this system possesses no wave-like modes but retains a single dynamical degree of freedom. Thus, the sound speed is always identically zero on all backgrounds. In particular, cosmological perturbations reproduce the standard behaviour for hydrodynamics in the limit of vanishing sound speed. Using all these properties we propose a model unifying Dark Matter and Dark Energy in a single degree of freedom. In a certain limit this model exactly reproduces the evolution history of ΛCDM, while deviations away from the standard expansion history produce a potentially measurable difference in the evolution of structure

  11. Aerosol-ozone correlations during dust transport episodes

    Directory of Open Access Journals (Sweden)

    P. Bonasoni

    2004-01-01

    Full Text Available Its location in the Mediterranean region and its physical characteristics render Mt. Cimone (44°11′ N, 10°42′ E, the highest peak of the Italian northern Apennines (2165 m asl, particularly suitable to study the transport of air masses from the north African desert area to Europe. During these northward transports 12 dust events were registered in measurements of the aerosol concentration at the station during the period June–December 2000, allowing the study of the impact of mineral dust transports on free tropospheric ozone concentrations, which were also measured at Mt. Cimone. Three-dimensional backward trajectories were used to determine the air mass origin, while TOMS Aerosol Index data for the Mt. Cimone area were used to confirm the presence of absorbing aerosol over the measurement site. A trajectory statistical analysis allowed identifying the main source areas of ozone and aerosols. The analysis of these back trajectories showed that central Europe and north and central Italy are the major pollution source areas for ozone and fine aerosol, whereas the north African desert regions were the most important source areas for coarse aerosol and low ozone concentrations. During dust events, the Mt. Cimone mean volume concentration for coarse particles was 6.18 µm3/cm3 compared to 0.63 µm3/cm3 in dust-free conditions, while the ozone concentrations were 4% to 21% lower than the monthly mean background values. Our observations show that surface ozone concentrations were lower than the background values in air masses coming from north Africa, and when these air masses were also rich in coarse particles, the lowest ozone values were registered. Moreover, preliminary results on the possible impact of the dust events on PM10 and ozone values measured in Italian urban and rural areas showed that during the greater number of the considered dust events, significant PM10 increases and ozone decreases have occurred in the Po valley.

  12. Ulysses dust measurements near Jupiter.

    Science.gov (United States)

    Grün, E; Zook, H A; Baguhl, M; Fechtig, H; Hanner, M S; Kissel, J; Lindblad, B A; Linkert, D; Linkert, G; Mann, I B

    1992-09-11

    Submicrometer- to micrometer-sized particles were recorded by the Ulysses dust detector within 40 days of the Jupiter flyby. Nine impacts were recorded within 50 Jupiter radii with most of them recorded after closest approach. Three of these impacts are consistent with particles on prograde orbits around Jupiter and the rest are believed to have resulted from gravitationally focused interplanetary dust. From the ratio of the impact rate before the Jupiter flyby to the impact rate after the Jupiter flyby it is concluded that interplanetary dust particles at the distance of Jupiter move on mostly retrograde orbits. On 10 March 1992, Ulysses passed through an intense dust stream. The dust detector recorded 126 impacts within 26 hours. The stream particles were moving on highly inclined and apparently hyperbolic orbits with perihelion distances of >5 astronomical units. Interplanetary dust is lost rather quickly from the solar system through collisions and other mechanisms and must be almost continuously replenished to maintain observed abundances. Dust flux measurements, therefore, give evidence of the recent rates of production from sources such as comets, asteroids, and moons, as well as the possible presence of interstellar grains.

  13. Experiments on Dust Grain Charging

    Science.gov (United States)

    Abbas, M. N.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; West, E. A.

    2004-01-01

    Dust particles in various astrophysical environments are charged by a variety of mechanisms generally involving collisional processes with other charged particles and photoelectric emission with UV radiation from nearby sources. The sign and the magnitude of the particle charge are determined by the competition between the charging processes by UV radiation and collisions with charged particles. Knowledge of the particle charges and equilibrium potentials is important for understanding of a number of physical processes. The charge of a dust grain is thus a fundamental parameter that influences the physics of dusty plasmas, processes in the interplanetary medium and interstellar medium, interstellar dust clouds, planetary rings, cometary and outer atmospheres of planets etc. In this paper we present some results of experiments on charging of dust grains carried out on a laboratory facility capable levitating micron size dust grains in an electrodynamic balance in simulated space environments. The charging/discharging experiments were carried out by exposing the dust grains to energetic electron beams and UV radiation. Photoelectric efficiencies and yields of micron size dust grains of SiO2, and lunar simulates obtained from NASA-JSC will be presented.

  14. FROM DUST TO PLANETESIMAL: THE SNOWBALL PHASE?

    International Nuclear Information System (INIS)

    Xie Jiwei; Zhou Jilin; Payne, Matthew J.; Ge Jian; Thebault, Philippe

    2010-01-01

    The standard model of planet formation considers an initial phase in which planetesimals form from a dust disk, followed by a phase of mutual planetesimal-planetesimal collisions, leading eventually to the formation of planetary embryos. However, there is a potential transition phase (which we call the 'snowball phase'), between the formation of the first planetesimals and the onset of mutual collisions amongst them, which has often been either ignored or underestimated in previous studies. In this snowball phase, isolated planetesimals move in Keplerian orbits and grow solely via the direct accretion of subcentimeter-sized dust entrained with the gas in the protoplanetary disk. Using a simplified model in which planetesimals are progressively produced from the dust, we consider the expected sizes to which the planetesimals can grow before mutual collisions commence and derive the dependence of this size on a number of critical parameters, including the degree of disk turbulence, the planetesimal size at birth, and the rate of planetesimal creation. For systems in which turbulence is weak and the planetesimals are created at a low rate and with relatively small birth size, we show that the snowball growth phase can be very important, allowing planetesimals to grow by a factor of 10 6 in mass before mutual collisions take over. In such cases, the snowball growth phase can be the dominant mode to transfer mass from the dust to planetesimals. Moreover, such growth can take place within the typical lifetime of a protoplanetary gas disk. A noteworthy result is that, for a wide range of physically reasonable parameters, mutual collisions between planetesimals become significant when they reach sizes ∼100 km, irrespective of their birth size. This could provide an alternative explanation for the turnover point in the size distribution of the present-day asteroid belt. For the specific case of close binaries such as α Centauri, the role of snowball growth could be even

  15. A novel passive water sampler for in situ sampling of antibiotics.

    Science.gov (United States)

    Chen, Chang-Er; Zhang, Hao; Jones, Kevin C

    2012-05-01

    Passive water sampling has several advantages over active methods; it provides time-integrated data, can save on time and cost compared to active methods, and yield high spatial resolution data through co-deployment of simple, cheap units. However, one problem with many sampler designs in current use is that their uptake rates for trace substances of interest are flow-rate dependent, thereby requiring calibration data and other information to enable water concentrations to be derived from the mass per sampler. However, the 'family' of samplers employing the principle of diffusive gradients in thin films (DGT) provides an in situ means of quantitatively measuring labile species in aquatic systems without field calibration. So far, this technique has only been tested and applied in inorganic substances: metals, radionuclides, nutrients, etc. Design and applications of DGT to trace organic contaminants ('o-DGT') would be of widespread interest. This study describes the laboratory testing and performance characteristics of o-DGT, with the antibiotic sulfamethoxazole (SMX) as a model compound and XAD18 as the novel binding agent. o-DGT uptake of SMX increased with time and decreased with diffusion layer thickness, confirming the principle for SMX. XAD18 showed sufficiently high capacity for SMX for routine field applications. o-DGT measurement of SMX was independent of pH (6-9) and ionic strength (0.001-0.1 M) and not affected by flow rate once above static conditions. The diffusion coefficient of SMX in the sampler was measured using an independent diffusion cell and information is presented to allow temperature correction and derivation of aqueous concentrations from deployed samplers. The potential use of o-DGT for in situ measurement of pharmaceutical antibiotics is confirmed by this study and applications are briefly discussed.

  16. A dust-free dock

    Energy Technology Data Exchange (ETDEWEB)

    Merrion, D. [E & F Services Ltd. (United Kingdom)

    2002-10-01

    This paper describes the process of unloading coal, petcoke and other dusty products in environmentally-sensitive areas. It presents a case study of the deepwater Port of Foynes on the west coast of Ireland which imports animal feed, fertiliser, coal and cement clinker, where dockside mobile loaders (DMLs) have eliminated spillage and controlled dust, and a record case study of the Humber International Terminal in the UK, where air curtinas, dust suppression grids and EFFEX{reg_sign} filters overcome the dust problems. 2 photos.

  17. Triton's streaks as windblown dust

    Science.gov (United States)

    Sagan, Carl; Chyba, Christopher

    1990-01-01

    Explanations for the surface streaks observed by Voyager 2 on Triton's southern hemisphere are discussed. It is shown that, despite Triton's tenuous atmosphere, low-cohesion dust trains with diameters of about 5 micron or less may be carried into suspension by aeolian surface shear stress, given expected geostrophic wind speeds of about 10 m/s. For geyser-like erupting dust plumes, it is shown that dust-settling time scales and expected wind velocities can produce streaks with length scales in good agreement with those of the streaks. Thus, both geyserlike eruptions or direct lifting by surface winds appear to be viable mechanisms for the origin of the streaks.

  18. [Asthma due to grain dust].

    Science.gov (United States)

    Baur, X; Preisser, A; Wegner, R

    2003-06-01

    The actual literature as well as two case reports described in detail show that grain dust induces asthmatic reactions and ODTS which are obviously not of allergic origin. For diagnosis occupational-type exposure tests are decisive whereas allergological testing usually is not. Endotoxins which are present in the grain dust samples in high concentrations have to be regarded as the major causative components. To avoid irreversible lung function impairment a comprehensive early diagnosis is necessary. Generally, a remarkable reduction of exposure to dust with high levels of airborne endotoxin in agriculture has to be achieved since in many workplaces corresponding exposures are still rather high.

  19. Dust Dynamics Near Planetary Surfaces

    Science.gov (United States)

    Colwell, Joshua; Hughes, Anna; Grund, Chris

    Observations of a lunar "horizon glow" by several Surveyor spacecraft in the 1960s opened the study of the dynamics of charged dust particles near planetary surfaces. The surfaces of the Moon and other airless planetary bodies in the solar system (asteroids, and other moons) are directly exposed to the solar wind and ionizing solar ultraviolet radiation, resulting in a time-dependent electric surface potential. Because these same objects are also exposed to bombardment by micrometeoroids, the surfaces are usually characterized by a power-law size distribution of dust that extends to sub-micron-sized particles. Individual particles can acquire a charge different from their surroundings leading to electrostatic levitation. Once levitated, particles may simply return to the surface on nearly ballistic trajectories, escape entirely from the moon or asteroid if the initial velocity is large, or in some cases be stably levitated for extended periods of time. All three outcomes have observable consequences. Furthermore, the behavior of charged dust near the surface has practical implications for planned future manned and unmanned activities on the lunar surface. Charged dust particles also act as sensitive probes of the near-surface plasma environment. Recent numerical modeling of dust levitation and transport show that charged micron-sized dust is likely to accumulate in topographic lows such as craters, providing a mechanism for the creation of dust "ponds" observed on the asteroid 433 Eros. Such deposition can occur when particles are supported by the photoelectron sheath above the dayside and drift over shadowed regions of craters where the surface potential is much smaller. Earlier studies of the lunar horizon glow are consistent with those particles being on simple ballistic trajectories following electrostatic launching from the surface. Smaller particles may be accelerated from the lunar surface to high altitudes consistent with observations of high altitude

  20. Dust visualisation in TJ-II with intensified visible fast cameras

    International Nuclear Information System (INIS)

    Cal, E. de la; Pablos, J. L. de; Carralero, D.; Hidalgo, C.

    2010-01-01

    A visible fast camera equipped with an image Intensifier and atomic line filters is used in TJ-II for spectroscopic dust observation. First results show characteristic features depending on filter and clearly differing from those without the filters as is usually done in existing experiments. Preliminary discussions of the observed results are presented. (Author) 5 refs.

  1. Dust visualisation in TJ-II with intensified visible Fast Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Cal, E. de la; Pablos, J. L. de; Carralero, D.; Hidalgo, C.

    2010-10-21

    A visible fast camera equipped with an image Intensifier and atomic line filters is used in TJ-II for spectroscopic dust observation. First results show characteristic features depending on filter and clearly differing from those without the filters as is usually done in existing experiments. Preliminary discussions of the observed results are presented. (Author) 5 refs.

  2. Bounded dust-acoustic waves in a cylindrically bounded collisional dusty plasma with dust charge variation

    International Nuclear Information System (INIS)

    Wei Nanxia; Xue Jukui

    2006-01-01

    Taking into account the boundary, particle collisions, and dust charging effects, dust-acoustic waves in a uniform cylindrically bounded dusty plasma is investigated analytically, and the dispersion relation for the dust-acoustic wave is obtained. The effects of boundary, dust charge variation, particle collision, and dust size on the dust-acoustic wave are discussed in detail. Due to the bounded cylindrical boundary effects, the radial wave number is discrete, i.e., the spectrum is discrete. It is shown that the discrete spectrum, the adiabatic dust charge variation, dust grain size, and the particle collision have significant effects on the dust-acoustic wave

  3. Associations between bacterial communities of house dust and infant gut

    Energy Technology Data Exchange (ETDEWEB)

    Konya, T.; Koster, B. [Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto (Canada); Maughan, H. [Department of Cell and Systems Biology, University of Toronto (Canada); Escobar, M. [Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto (Canada); Azad, M. B. [Department of Pediatrics, University of Alberta (Canada); Guttman, D. S. [Department of Cell and Systems Biology, University of Toronto (Canada); Sears, M. R. [Department of Medicine, McMaster University (Canada); Becker, A. B. [University of Manitoba (Canada); Brook, J. R. [Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto (Canada); Environment Canada (Canada); Takaro, T. K. [Faculty of Health Science, Simon Fraser University (Canada); Kozyrskyj, A. L. [Department of Pediatrics, University of Alberta (Canada); Scott, J.A., E-mail: james.scott@utoronto.ca [Division of Occupational and Environmental Health, Dalla Lana School of Public Health, University of Toronto (Canada)

    2014-05-01

    The human gut is host to a diverse and abundant community of bacteria that influence health and disease susceptibility. This community develops in infancy, and its composition is strongly influenced by environmental factors, notably perinatal anthropogenic exposures such as delivery mode (Cesarean vs. vaginal) and feeding method (breast vs. formula); however, the built environment as a possible source of exposure has not been considered. Here we report on a preliminary investigation of the associations between bacteria in house dust and the nascent fecal microbiota from 20 subjects from the Canadian Healthy Infant Longitudinal Development (CHILD) Study using high-throughput sequence analysis of portions of the 16S rRNA gene. Despite significant differences between the dust and fecal microbiota revealed by Nonmetric Multidimensional Scaling (NMDS) analysis, permutation analysis confirmed that 14 bacterial OTUs representing the classes Actinobacteria (3), Bacilli (3), Clostridia (6) and Gammaproteobacteria (2) co-occurred at a significantly higher frequency in matched dust–stool pairs than in randomly permuted pairs, indicating an association between these dust and stool communities. These associations could indicate a role for the indoor environment in shaping the nascent gut microbiota, but future studies will be needed to confirm that our findings do not solely reflect a reverse pathway. Although pet ownership was strongly associated with the presence of certain genera in the dust for dogs (Agrococcus, Carnobacterium, Exiguobacterium, Herbaspirillum, Leifsonia and Neisseria) and cats (Escherichia), no clear patterns were observed in the NMDS-resolved stool community profiles as a function of pet ownership.

  4. Associations between bacterial communities of house dust and infant gut

    International Nuclear Information System (INIS)

    Konya, T.; Koster, B.; Maughan, H.; Escobar, M.; Azad, M.B.; Guttman, D.S.; Sears, M.R.; Becker, A.B.; Brook, J.R.; Takaro, T.K.; Kozyrskyj, A.L.; Scott, J.A.

    2014-01-01

    The human gut is host to a diverse and abundant community of bacteria that influence health and disease susceptibility. This community develops in infancy, and its composition is strongly influenced by environmental factors, notably perinatal anthropogenic exposures such as delivery mode (Cesarean vs. vaginal) and feeding method (breast vs. formula); however, the built environment as a possible source of exposure has not been considered. Here we report on a preliminary investigation of the associations between bacteria in house dust and the nascent fecal microbiota from 20 subjects from the Canadian Healthy Infant Longitudinal Development (CHILD) Study using high-throughput sequence analysis of portions of the 16S rRNA gene. Despite significant differences between the dust and fecal microbiota revealed by Nonmetric Multidimensional Scaling (NMDS) analysis, permutation analysis confirmed that 14 bacterial OTUs representing the classes Actinobacteria (3), Bacilli (3), Clostridia (6) and Gammaproteobacteria (2) co-occurred at a significantly higher frequency in matched dust–stool pairs than in randomly permuted pairs, indicating an association between these dust and stool communities. These associations could indicate a role for the indoor environment in shaping the nascent gut microbiota, but future studies will be needed to confirm that our findings do not solely reflect a reverse pathway. Although pet ownership was strongly associated with the presence of certain genera in the dust for dogs (Agrococcus, Carnobacterium, Exiguobacterium, Herbaspirillum, Leifsonia and Neisseria) and cats (Escherichia), no clear patterns were observed in the NMDS-resolved stool community profiles as a function of pet ownership

  5. Dust particle formation in silane plasmas

    NARCIS (Netherlands)

    Sorokin, M.

    2005-01-01

    Dust can be found anywhere: in the kitchen, in the car, in space… Not surprisingly we also see dust in commercial and laboratory plasmas. Dust can be introduced in the plasma, but it can also grow there by itself. In the microelectronics industry, contamination of the processing plasma by dust is an

  6. PERSPECTIVE: Dust, fertilization and sources

    Science.gov (United States)

    Remer, Lorraine A.

    2006-11-01

    Aerosols, tiny suspended particles in the atmosphere, play an important role in modifying the Earth's energy balance and are essential for the formation of cloud droplets. Suspended dust particles lifted from the world's arid regions by strong winds contain essential minerals that can be transported great distances and deposited into the ocean or on other continents where productivity is limited by lack of usable minerals [1]. Dust can transport pathogens as well as minerals great distance, contributing to the spread of human and agricultural diseases, and a portion of dust can be attributed to human activity suggesting that dust radiative effects should be included in estimates of anthropogenic climate forcing. The greenish and brownish tints in figure 1 show the wide extent of monthly mean mineral dust transport, as viewed by the MODerate resolution Imaging Spectroradiometer (MODIS) satellite sensor. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite Figure 1. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite. The brighter the color, the greater the aerosol loading. Red and reddish tints indicate aerosol dominated by small particles created primarily from combustion processes. Green and brownish tints indicate larger particles created from wind-driven processes, usually transported desert dust. Note the bright green band at the southern edge of the Saharan desert, the reddish band it must cross if transported to the southwest and the long brownish transport path as it crosses the Atlantic to South America. Image courtesy of the NASA Earth Observatory (http://earthobservatory.nasa.gov). Even though qualitatively we recognize the extent and importance of dust transport and the role that it plays in fertilizing nutrient-limited regions, there is much that is still unknown. We are just now beginning to quantify the amount of dust that exits one continental region and the

  7. Overview of Asian Biomass Burning and Dust Aerosols Measured during the Dongsha Experiment in the Spring of 2010

    Science.gov (United States)

    Lin, N.; Tsay, S.; Wang, S.; Sheu, G.; Chi, K.; Lee, C.; Wang, J.

    2010-12-01

    launched four times per day during the IOPs. This experiment provides a relatively complete dataset of aerosol chemistry and physical observations conducted in the source/sink region for below marine boundary layer and lower free troposphere of biomass burning/air pollutants in the northern SE Asia. This presentation will give an overview of this experiment and its preliminary results, including a severe and unusual Asian dust event that was observed in Dognsha Island.

  8. The orientation-averaged aspiration efficiency of IOM-like personal aerosol samplers mounted on bluff bodies.

    Science.gov (United States)

    Paik, Samuel Y; Vincent, James H

    2004-01-01

    This paper describes two sets of experiments that were intended to characterize the orientation-averaged aspiration efficiencies of IOM samplers mounted on rotating bluff bodies. IOM samplers were mounted on simplified, three-dimensional rectangular bluff bodies that were rotated horizontally at a constant rate. Orientation-averaged aspiration efficiencies (A360) were measured as a function of Stokes' number (St), velocity ratio (R) and dimension ratio (r). Aspiration efficiency (A) is the efficiency with which particles are transported from the ambient air into the body of a sampler, and A360 is A averaged over all orientations to the wind. St is a dimensionless variable that represents particle inertia, R is the ratio of the air velocity in the freestream and that at the plane of the sampler's entry orifice, and r is the ratio of the sampler's orifice diameter and the bluff body's width. The first set of experiments were instrumental in establishing a hierarchy of effects on orientation-averaged A. It was clear that compared to r, St had a much larger influence on A. It was also clear, however, that the effects of St were overpowered by the effects of R in many cases. As concluded in previous studies, R and St were considered the most important factors in determining A, even for A360. The second set of experiments investigated A360 of IOM samplers for a much wider range of r than examined in previous research. Two important observations were made from the experimental results. One was that the A360 of IOM samplers, as a function of St, did not change for an r-range of 0.066-0.4. This meant that an IOM sampler mounted on a near life-size mannequin would measure the same aerosol concentration as one not mounted on anything. The second observation was that the aspiration efficiency curve of the IOM sampler was close to the inhalability curve. This gave further evidence that the bluff body did not play a major role in influencing A360, as the IOM samplers, in these

  9. Loess and Eolian Dust Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past environment derived from Loess and Eolian dust (silt-sized material deposited on the Earth surface by the surface winds. Parameter keywords describe...

  10. 75 FR 3881 - Combustible Dust

    Science.gov (United States)

    2010-01-25

    ..., rubber, drugs, dried blood, dyes, certain textiles, and metals (such as aluminum and magnesium..., furniture manufacturing, metal processing, fabricated metal products and machinery manufacturing, pesticide... standard that will comprehensively address the fire and explosion hazards of combustible dust. The Agency...

  11. Rethinking wood dust safety standards

    OpenAIRE

    Ratnasingam, Jega; Wai, Lim Tau; Ramasamy, Geetha; Ioras, Florin; Tadin, Ishak; Universiti Putra Malaysia; Buckinghamshire New University; Centre for Occupational Safety and Health Singapore

    2015-01-01

    The current universal work safety and health standards pertaining to wood dust in factories lack the localisation required. As a study has shown, there is a urgent need to reevaluate the current guidelines and practices.

  12. Comparison of dust related respiratory effects in Dutch and Canadian grain handling industries: a pooled analysis.

    Science.gov (United States)

    Peelen, S J; Heederik, D; Dimich-Ward, H D; Chan-Yeung, M; Kennedy, S M

    1996-08-01

    Four previously conducted epidemiological studies in more than 1200 grain workers were used to compare exposure-response relations between exposure to grain dust and respiratory health. The studies included Dutch workers from an animal feed mill and a transfer grain elevator and Canadian workers from a terminal grain elevator and the docks. Relations between forced expiratory volume in one second (FEV1) and exposure were analysed with multiple regression analysis corrected for smoking, age, and height. Exposure variables examined included cumulative and current dust exposure and the numbers of years a subject was employed in the industry. Sampling efficiencies of the Dutch and Canadian measurement techniques were compared in a pilot study. Results of this study were used to correct slopes of exposure-response relations for differences in dust fractions sampled by Dutch and Canadian personal dust samplers. Negative exposure-response relations were shown for regressions of FEV1 on cumulative and current exposure and years employed. Slopes of the exposure-response relations differed by a factor of three to five between industries, apart from results for cumulative exposure. Here the variation in slopes differed by a factor of 100, from -1 to -0.009 ml/mg.y/m3. The variation in slopes between industries reduced to between twofold to fivefold when the Dutch transfer elevator workers were not considered. There was evidence that the small exposure-response slope found for this group is caused by misclassification of exposure and a strong healthy worker effect. Alternative, but less likely explanations for the variation in slopes were differences in exposure concentrations, composition of grain dust, exposure characteristics, and measurement techniques. In conclusion, this study showed moderately similar negative exposure-response relations for four different populations from different countries, despite differences in methods of exposure assessment and exposure estimation.

  13. Effect of changes in environment on the variation in elemental composition of airborne dust

    International Nuclear Information System (INIS)

    Miyamoto, Yutaka; Saito, Yoko; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu

    2004-01-01

    For the research on environmental impact caused by nuclear activities, we are developing monitoring technique to measure radioactivity, isotopic and elemental composition in airborne dust, which contains nuclear materials and radioactive elements released from nuclear facilities. We focus on its elimination process such as wash-out by rainfall and adsorption to plants in the processes which affect the amounts and composition of the airborne dust. Recently at JAERI-Tokai, a number of pine trees to arrest sand shifting were cut down. This gave us a good opportunity to examine the effect of presence of the trees on the variation in elemental composition of airborne dust, therefore, we collected dust samples with a high-volume sampler before and after felling the trees, and analyzed them by means of instrumental neutron activation analysis. No change was observed in the amount, Al- and Sc- concentrations of the dust collected before and after felling the trees nearby the sampling site. There were correlations between the elemental concentration of Zn and that of Sb, and between Zn and As. These elements might originate from some by-products of social activities such as fly ashes. If found that the concentration of these elements after felling the trees decrease to 60% of the concentration before the works. The histograms of concentration of Cl in the airborne samples were compiled using the samples which the average of relative humidity in the period of the sample collection was 70-80%. The Cl concentration in the airdust after felling the trees at the seaside was three times higher than that concentration before the works. It found that the trees can eliminate more effectively the aerosols such as sea-salt than soil from the atmosphere. (author)

  14. Physical properties of five grain dust types.

    OpenAIRE

    Parnell, C B; Jones, D D; Rutherford, R D; Goforth, K J

    1986-01-01

    Physical properties of grain dust derived from five grain types (soybean, rice, corn, wheat, and sorghum) were measured and reported. The grain dusts were obtained from dust collection systems of terminal grain handling facilities and were assumed to be representative of grain dust generated during the handling process. The physical properties reported were as follows: particle size distributions and surface area measurements using a Coulter Counter Model TAII; percent dust fractions less tha...

  15. Efficient radiative transfer in dust grain mixtures

    OpenAIRE

    Wolf, S.

    2002-01-01

    The influence of a dust grain mixture consisting of spherical dust grains with different radii and/or chemical composition on the resulting temperature structure and spectral energy distribution of a circumstellar shell is investigated. The comparison with the results based on an approximation of dust grain parameters representing the mean optical properties of the corresponding dust grain mixture reveal that (1) the temperature dispersion of a real dust grain mixture decreases substantially ...

  16. Grain dust and the lungs.

    Science.gov (United States)

    Chan-Yeung, M.; Ashley, M. J.; Grzybowski, S.

    1978-01-01

    Grain dust is composed of a large number of materials, including various types of grain and their disintegration products, silica, fungi, insects and mites. The clinical syndromes described in relation to exposure to grain dust are chronic bronchitis, grain dust asthma, extrinsic allergic alveolitis, grain fever and silo-filler's lung. Rhinitis and conjunctivitis are also common in grain workers. While the concentration and the quality of dust influence the frequency and the type of clinical syndrome in grain workers, host factors are also important. Of the latter, smoking is the most important factor influencing the frequency of chronic bronchitis. The role of atopy and of bronchial hyperreactivity in grain dust asthma has yet to be assessed. Several well designed studies are currently being carried out in North America not only to delineate the frequency of the respiratory abnormalities, the pathogenetic mechanisms and the host factors, but also to establish a meaningful threshold limit concentration for grain dust. Images p1272-a PMID:348288

  17. Charged dust structures in plasmas

    International Nuclear Information System (INIS)

    Cramer, N.F.; Vladimirov, S.V.

    1999-01-01

    We report here on theoretical investigations of the mechanical-electrostatic modes of vibration of a dust-plasma crystal, extending earlier work on the transverse modes of a horizontal line of grains (where the ions flow vertically downward to a plane horizontal cathode), the modes of two such lines of grains, and the modes of a vertical string of grains. The last two arrangements have the unique feature that the effect of the background plasma on the mutual grain interaction is asymmetric because of the wake downstream of the grains studied in. The characteristic frequencies of the vibrations are dependent on the parameters of the plasma and the dust grains, such as the Debye length and the grain charge, and so measurement of the frequencies could provide diagnostics of these quantities. Although the current boom in dusty plasma research is driven mainly by such industrial applications as plasma etching, sputtering and deposition, the physical outcomes of investigations in this rapidly expanding field cover many important topics in space physics and astrophysics as well. Examples are the interaction of dust with spacecraft, the structure of planetary rings, star formation, supernova explosions and shock waves. In addition, the study of the influence of dust in environmental research, such as in the Earth's ionosphere and atmosphere, is important. The unique binding of dust particles in a plasma opens possibilities for so-called super-chemistry, where the interacting bound elements are not atoms but dust grains

  18. Suspended dust in Norwegian cities

    International Nuclear Information System (INIS)

    2001-01-01

    According to calculations, at least 80 000 people in Oslo and 8 000 in Trondheim were annoyed by too much suspended dust in 2000. The dust concentration is greatest in the spring, presumably because dust is swirling up from melting snow and ice on the streets. Car traffic is the main source of the dust, except for some of the most highly exposed regions where wood-firing from old stoves contributes up to 70 percent of the dust. National targets for air quality include suspended dust, nitrogen dioxide, sulphur dioxide and benzene. Calculations show that nitrogen dioxide emissions exceeding the limit affected 4 000 people in Oslo and 1 000 people in Trondheim. The sulphur dioxide emissions in the major cities did non exceed the national quality limit; they did exceed the limit in some of the smaller industrial centres. In Trondheim, measurements show that the national limit for benzene was exceeded. Most of the emission of nitrogen dioxide comes from the road traffic. Local air pollution at times causes considerable health- and well-being problems in the larger cities and industrial centres, where a great part of the population may be at risk of early death, infection of the respiratory passage, heart- and lung diseases and cancer

  19. Integrated passive flux measurement in groundwater: design and performance of iFLUX samplers

    Science.gov (United States)

    Verreydt, Goedele; Razaei, Meisam; Meire, Patrick; Van Keer, Ilse; Bronders, Jan; Seuntjens, Piet

    2017-04-01

    The monitoring and management of soil and groundwater is a challenge. Current methods for the determination of movement or flux of pollution in groundwater use no direct measurements but only simulations based on concentration measurements and Darcy velocity estimations. This entails large uncertainties which cause remediation failures and higher costs for contaminated site owners. On top of that, the lack of useful data makes it difficult to get approval for a risk-based management approach which completely avoids costly remedial actions. The iFLUX technology is a key development of Dr. Goedele Verreydt at the University of Antwerp and VITO. It is supported by the passive flux measurement technology as invented by Prof. Mike Annable and his team at the University of Florida. The iFLUX technology includes an in situ measurement device for capturing dynamic groundwater quality and quantity, the iFLUX sampler, and an associated interpretation and visualization method. The iFLUX sampler is a modular passive sampler that provides simultaneous in situ point determinations of a time-averaged target compound mass flux and water flux. The sampler is typically installed in a monitoring well where it intercepts the groundwater flow and captures the compounds of interest. The sampler consists of permeable cartridges which are each packed with a specific sorbent matrix. The sorbent matrix of the water flux cartridge is impregnated with known amounts of water soluble resident tracers. These tracers are leached from the matrix at rates proportional to the groundwater flux. The measurements of the contaminants and the remaining resident tracer are used to determine groundwater and target compound fluxes. Exposure times range from 1 week to 6 months, depending on the expected concentration and groundwater flow velocity. The iFLUX sampler technology has been validated and tested at several field projects. Currently, 4 cartridges are tested and available: 1 waterflux cartridge to

  20. Carbon Nanotube Integrative Sampler (CNIS) for passive sampling of nanosilver in the aquatic environment.

    Science.gov (United States)

    Shen, Li; Fischer, Jillian; Martin, Jonathan; Hoque, Md Ehsanul; Telgmann, Lena; Hintelmann, Holger; Metcalfe, Chris D; Yargeau, Viviane

    2016-11-01

    Nanomaterials such as nanosilver (AgNP) can be released into the aquatic environment through production, usage, and disposal. Sensitive and cost-effective methods are needed to monitor AgNPs in the environment. This work is hampered by a lack of sensitive methods to detect nanomaterials in environmental matrixes. The present study focused on the development, calibration and application of a passive sampling technique for detecting AgNPs in aquatic matrixes. A Carbon Nanotube Integrative Sampler (CNIS) was developed using multi-walled carbon nanotubes (CNTs) as the sorbent for accumulating AgNPs and other Ag species from water. Sampling rates were determined in the laboratory for different sampler configurations and in different aquatic matrixes. The sampler was field tested at the Experimental Lakes Area, Canada, in lake water dosed with AgNPs. For a configuration of the CNIS consisting of CNTs bound to carbon fiber (i.e. CNT veil) placed in Chemcatcher® housing, the time weighted average (TWA) concentrations of silver estimated from deployments of the sampler in lake mesocosms dosed with AgNPs were similar to the measured concentrations of "colloidal silver" (i.e. <0.22μm in size) in the water column. For a configuration of CNIS consisting of CNTs in loose powder form placed in a custom made housing that were deployed in a whole lake dosed with AgNPs, the estimated TWA concentrations of "CNIS-labile Ag" were similar to the concentrations of total silver measured in the epilimnion of the lake. However, sampling rates for the CNIS in various matrixes are relatively low (i.e. 1-20mL/day), so deployment periods of several weeks are required to detect AgNPs at environmentally relevant concentrations, which can allow biofilms to develop on the sampler and could affect the sampling rates. With further development, this novel sampler may provide a simple and sensitive method for screening for the presence of AgNPs in surface waters. Copyright © 2016 Elsevier B.V. All

  1. Rapid monitoring of soil, smears, and air dusts by direct large-area alpha spectrometry

    International Nuclear Information System (INIS)

    Sill, C.W.

    1992-01-01

    Experimental conditions to permit rapid monitoring of soils, smears, and air dusts for transuranic (TRU) radionuclides under field conditions are described. The monitoring technique involves direct measurement of alpha emitters by alpha spectrometry using a large-area detector to identify and quantify the radionuclides present. The direct alpha spectrometry employs a circular gridded ionization chamber 35 cm in diameter which accommodates either a circular sample holder 25 cm in diameter or a rectangular one 20 by 25 cm (8 by 10 in.). Soils or settled dusts are finely ground, suspended in 30% ethanol, and sprayed onto a 25-cm stainless steel dish. Air dusts are collected with a high-volume sampler onto 20- by 25-cm membrane filters. Removable contamination is collected from surfaces onto a 20- by 25-cm filter using an 18-cm (7-in.) paint roller to hold the large filter in contact with the surface during sample collection. All three types of samples are then counted directly in the alpha spectrometer and no other sample preparation is necessary. Some results obtained are described

  2. Transport and trapping of dust particles in a potential well created by inductively coupled diffused plasmas.

    Science.gov (United States)

    Choudhary, Mangilal; Mukherjee, S; Bandyopadhyay, P

    2016-05-01

    A versatile linear dusty (complex) plasma device is designed to study the transport and dynamical behavior of dust particles in a large volume. Diffused inductively coupled plasma is generated in the background of argon gas. A novel technique is used to introduce the dust particles in the main plasma by striking a secondary direct current glow discharge. These dust particles are found to get trapped in an electrostatic potential well, which is formed due to the combination of the ambipolar electric field caused by diffusive plasma and the field produced by the charged glass wall of the vacuum chamber. According to the requirements, the volume of the dust cloud can be controlled very precisely by tuning the plasma and discharge parameters. The present device can be used to address the underlying physics behind the transport of dust particles, self-excited dust acoustic waves, and instabilities. The detailed design of this device, plasma production and characterization, trapping and transport of the dust particle, and some of the preliminary experimental results are presented.

  3. Ammonia leaching of copper smelter dust and precipitation as copper sulphide; Lixiviacion amoniacal de polvos de fundicion de cobre y precipitacion como sulfuro de cobre

    Energy Technology Data Exchange (ETDEWEB)

    Morales, A.; Hevia, J. F.; Cifuentes, G.

    2009-07-01

    The effect of ammonia on the leaching of copper smelter dust and copper precipitation from these solutions as sulphide using sulfur and sulfur dioxide was studied. The precipitation was done in ammoniacal media because this solution produced more satisfactory results at room temperature that a sulphuric media. A solid was precipitated containing 60 % of copper of the dust smelter. The other waste generated contained around 80 % of the arsenic of the original copper smelter dust. Based on the preliminary results obtained in this work it will propose a procedure for the recovery of copper as sulphide from copper smelter dust with parallel confinement of arsenic. (Author) 14 refs.

  4. Identifying sources of respirable quartz and silica dust in underground coal mines in southern West Virginia, western Virginia, and eastern Kentucky

    Energy Technology Data Exchange (ETDEWEB)

    Schatzel, Steven J. [National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, 626 Cochrans Mill Road, PO Box 18070, Pittsburgh, PA 15236 (United States)

    2009-04-01

    Prior research has suggested that the source of respirable silica dust in underground coal mines is typically the immediate top or bottom lithology adjacent to the mined seam, not mineral matter bound within the mined coal bed. Geochemical analyses were applied in an effort to identify the specific source rock of respirable quartz dust in coal mines. The analyses also demonstrate the compositional changes that take place in the generation of the respirable dust fraction from parent rock material. All six mine sites were mining coal with relatively low mineral matter content, although two mines were operating in the Fire Clay coal bed which contains a persistent tonstein. Interpretations of Ca, Mg, Mn, Na, and K concentrations strongly suggest that the top strata above the mined seam is the primary source of mineral dust produced during mining. One site indicates a mixed or bottom source, possibly due to site specific conditions. Respirable dust compositional analyses suggest a direct relationship between the quantity of mineral Si and the quantity of quartz Si. A similar relationship was not found in either the top or bottom rocks adjacent to the mined seam. An apparent loss of elemental Al was noted in the respirable dust fraction when compared to potential parent rock sources. Elemental Al is present in top and bottom rock strata within illite, kaolinite, feldspar, and chlorite. A possible explanation for loss of Al in the respirable dust samples is the removal of clays and possibly chlorite minerals. It is expected that removal of this portion of the Al bearing mineral matter occurs during rock abrasion and dust transport prior to dust capture on the samplers. (author)

  5. Benthic organisms collected using sediment sampler from the CAPT. BRADY J in the Gulf of Mexico from (NODC Accession 8300082)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic organisms were collected using sediment sampler casts from the CAPT. BRADY J and CAJUN SPECIAL in the Gulf of Mexico from 03 May 1982 to 13 October 1982....

  6. Regional transport of a chemically distinctive dust: Gypsum from White Sands, New Mexico (USA)

    Science.gov (United States)

    White, Warren H.; Hyslop, Nicole P.; Trzepla, Krystyna; Yatkin, Sinan; Rarig, Randy S.; Gill, Thomas E.; Jin, Lixin

    2015-03-01

    The White Sands complex, a National Monument and adjoining Missile Range in southern New Mexico, occupies the dry bed of an ice-age lake where an active gypsum dunefield abuts erodible playa sediments. Aerosols entrained from White Sands are sometimes visible on satellite images as distinct, light-colored plumes crossing the Sacramento Mountains to the east and northeast. The IMPROVE network (Interagency Monitoring of PROtected Visual Environments) operates long-term aerosol samplers at two sites east of the Sacramento range. In recent years a spring pulse of sulfate aerosol has appeared at these sites, eclipsing the regional summer peak resulting from atmospheric reactions of sulfur dioxide emissions. A significant fraction of this spring sulfate is contributed by gypsum and other salts from White Sands, with much of the sulfur in coarse particles and concentrations of calcium and strontium above regional levels. The increase in these gypsiferous species coincides with a drought following a period of above-average precipitation. White Sands and the IMPROVE samplers together provide a natural laboratory: a climatically sensitive dust source that is both well characterized and chemically distinct from its surroundings, with a signature that remains identifiable at long-term observatories 100-200 km downwind.

  7. Development of an automatic smear sampler and evaluation of surface contamination

    International Nuclear Information System (INIS)

    Seo, B. K.; Lee, B. J.; Lee, K. W.; Park, J. H.

    2004-01-01

    The surface contamination level of a radiation-controlled area is measured periodically according to atomic energy law and connection regulations. The measurement of surface contamination by an indirect method is subject to various kinds of error depending on the sampling person and consumes much time and effort in the sampling of large nuclear facilities. In this research, an automatic smear sampler is developed to solve these problems. The developed equipment is composed of a rotating sampling part, a sample transferring part, a power supply part a control part, and vacuum part. It improved the efficiency of estimation of the surface contamination level achieved periodically in a radiation-controlled area. Using an automatic smear sampler developed in this research, it is confirmed that radioactive contaminated materials are uniformly transferred to smear paper more than any sampling method by an operator. (authors)

  8. Calibration sources for the G-M counter used with the BNL air sampler

    International Nuclear Information System (INIS)

    Huchton, R.L.; Bird, S.K.; Tkachyk, J.W.; Motes, B.G.

    1983-12-01

    Three calibration sources were designed, developed, and fabricated for a CDV-700 ratemeter equipped with a specially-shielded 6306 G-M detector. The CDV-700/6306 has been proposed for use with the BNL Air Sampler designed for radioiodine monitoring upon a nuclear reactor accident. Specifically, three sources were constructed in a geometry identical to the BNL Air Sampler radioiodine adsorption canister, which is a silver-silica-gel filled 2.75-inch diameter right circular cylinder with a 1.0 inch daimater annulus for insertion of the 6306 G-M detector. As fabricated, each source consisted of an outer stainless steel housing, an inner 133 Ba impregnated polyester liner, 4 weight percent silver steel lid. Respectively, the levels of 133 Ba, an 131 I simulant, were varied in the three sources to yield nominal CDV-700/6306 instrument responses of 200 cpm, 2000 cpm, and 20,000 cpm

  9. A new sampler for simulating aerosol deposition in the respiratory tract

    International Nuclear Information System (INIS)

    Li Dehong; Zhuo Weihai; Yi Yanling; Chen Bo; Liu Haikuan

    2008-01-01

    For estimation of the deposition fractions of radon progeny in different regions of the respiratory tract, a new sampler consisting of three different configurations of sampling heads was developed. The deposition fractions of aerosols on the wire screens inside the sampling heads were calculated with the fan model of filtration theory. The deposition fractions of aerosols in different regions of the respiratory tract were calculated with the lung dose evaluation program (LUDEP) developed by National Radiological Protection Board (NRPB) as references. In general indoor and mine environments, the deviation between the deposition fractions of attached aerosol on the wire screens designed in this study and its reference values in the respiratory tract is less than 5%. It is possible to accurately estimate the deposition fractions of radon progeny in different regions of the respiratory tract through mimic measurements of radon progeny collected with the new sampler. (authors)

  10. Passive sampling of selected endocrine disrupting compounds using polar organic chemical integrative samplers

    International Nuclear Information System (INIS)

    Arditsoglou, Anastasia; Voutsa, Dimitra

    2008-01-01

    Two types of polar organic chemical integrative samplers (pharmaceutical POCIS and pesticide POCIS) were examined for their sampling efficiency of selected endocrine disrupting compounds (EDCs). Laboratory-based calibration of POCISs was conducted by exposing them at high and low concentrations of 14 EDCs (4-alkyl-phenols, their ethoxylate oligomers, bisphenol A, selected estrogens and synthetic steroids) for different time periods. The kinetic studies showed an integrative uptake up to 28 days. The sampling rates for the individual compounds were obtained. The use of POCISs could result in an integrative approach to the quality status of the aquatic systems especially in the case of high variation of water concentrations of EDCs. The sampling efficiency of POCISs under various field conditions was assessed after their deployment in different aquatic environments. - Calibration and field performance of polar organic integrative samplers for monitoring EDCs in aquatic environments

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. A Compact Diffusion Sampler for Environmental Applications Requiring HTO or HTO + HT Determinations

    International Nuclear Information System (INIS)

    Otlet, R.L.; Walker, A.J.; Mather, I.D.

    2005-01-01

    Passive diffusion samplers have now been in use in the UK for the measurement of tritium at environmental levels in the form of HTO and HTO + HT for more than ten years. At the outset their main purpose was to identify the direction of a possible inadvertent release of tritium into the environment. More recently, however, there has been growing interest in their use as stand-alone devices for tritium determination at environmental levels. This has necessitated a more rigorous design to reduce the 'draughts effect' in exposed locations and has also required modifications to enable the measurement of HTO + HT. The paper describes the recent design improvements and the results of validation tests carried out against dynamic, discriminating (dry-bed) samplers

  13. Study on treatment of dust by dismantling

    International Nuclear Information System (INIS)

    Torikai, K.; Suzuki, K.

    1987-01-01

    In dismantling of nuclear reactors, various kinds of treatment of dust generated by cutting or dismantling concrete structures of components of reactors are evaluated for safety, cost, and performance comparing the work in air with water. A method of dust treatment for work in air is discussed. The dry method has an easy operation in practice and a good performance in the equipment, but has problem on the prevention from radioactive contamination by diffusion of dust in air. For the purpose of advancing the strong points and eliminating the weak points in dry method, an improved venturi scrubber system is proposed for dismantling work as a dust collecting system. The system consists of dust absorbing pipe, dust collector, separator of dust and water and dust transfer equipment to a storage of waste. This system would be expected to have better performance and lower operating cost in decommissioning nuclear reactors, especially, the number of dust filters, for example, HEPA filters, will be considerably saved

  14. Field comparison of three inhalable samplers (IOM, PGP-GSP 3.5 and Button) for welding fumes.

    Science.gov (United States)

    Zugasti, Agurtzane; Montes, Natividad; Rojo, José M; Quintana, M José

    2012-02-01

    Inhalable sampler efficiency depends on the aerodynamic size of the airborne particles to be sampled and the wind speed. The aim of this study was to compare the behaviour of three personal inhalable samplers for welding fumes generated by Manual Metal Arc (MMA) and Metal Active Gas (MAG) processes. The selected samplers were the ones available in Spain when the study began: IOM, PGP-GSP 3.5 (GSP) and Button. Sampling was carried out in a welding training center that provided a homogeneous workplace environment. The static sampling assembly used allowed the placement of 12 samplers and 2 cascade impactors simultaneously. 183 samples were collected throughout 2009 and 2010. The range of welding fumes' mass concentrations was from 2 mg m(-3) to 5 mg m(-3). The pooled variation coefficients for the three inhalable samplers were less than or equal to 3.0%. Welding particle size distribution was characterized by a bimodal log-normal distribution, with MMADs of 0.7 μm and 8.2 μm. For these welding aerosols, the Button and the GSP samplers showed a similar performance (P = 0.598). The mean mass concentration ratio was 1.00 ± 0.01. The IOM sampler showed a different performance (P IOM and 0.92 ± 0.02 for GSP/IOM. This information is useful to consider the measurements accomplished by the IOM, GSP or Button samplers together, in order to assess the exposure at workplaces over time or to study exposure levels in a specific industrial activity, as welding operations.

  15. WHATS-3: An improved flow-through multi-bottle fluid sampler for deep-sea geofluid research

    Science.gov (United States)

    Miyazaki, Junichi; Makabe, Akiko; Matsui, Yohei; Ebina, Naoya; Tsutsumi, Saki; Ishibashi, Jun-ichiro; Chen, Chong; Kaneko, Sho; Takai, Ken; Kawagucci, Shinsuke

    2017-06-01

    Deep-sea geofluid systems, such as hydrothermal vents and cold seeps, are key to understanding subseafloor environments of Earth. Fluid chemistry, especially, provides crucial information towards elucidating the physical, chemical and biological processes that occur in these ecosystems. To accurately assess fluid and gas properties of deep-sea geofluids, well-designed pressure-tight fluid samplers are indispensable and as such they are important assets of deep-sea geofluid research. Here, the development of a new flow-through, pressure-tight fluid sampler capable of four independent sampling events (two subsamples for liquid and gas analyses from each) is reported. This new sampler, named WHATS-3, is a new addition to the WHATS-series samplers and a major upgrade from the previous WHATS-2 sampler with improvements in sample number, valve operational time, physical robustness, and ease of maintenance. Routine laboratory-based pressure tests proved that it is suitable for operation up to 35 MPa pressure. Successful field tests of the new sampler were also carried out in five hydrothermal fields, two in Indian Ocean and three in Okinawa Trough (max. depth 3,300 m). Relations of Mg and major ion species demonstrated bimodal mixing trends between a hydrothermal fluid and seawater, confirming the high-quality of fluids sampled. The newly developed WHATS-3 sampler is well-balanced in sampling capability, field usability, and maintenance feasibility, and can serve as one of the best geofluid samplers available at present to conduct efficient research of deep-sea geofluid systems.

  16. WHATS-3: An Improved Flow-Through Multi-bottle Fluid Sampler for Deep-Sea Geofluid Research

    Directory of Open Access Journals (Sweden)

    Junichi Miyazaki

    2017-06-01

    Full Text Available Deep-sea geofluid systems, such as hydrothermal vents and cold seeps, are key to understanding subseafloor environments of Earth. Fluid chemistry, especially, provides crucial information toward elucidating the physical, chemical, and biological processes that occur in these ecosystems. To accurately assess fluid and gas properties of deep-sea geofluids, well-designed pressure-tight fluid samplers are indispensable and as such they are important assets of deep-sea geofluid research. Here, the development of a new flow-through, pressure-tight fluid sampler capable of four independent sampling events (two subsamples for liquid and gas analyses from each is reported. This new sampler, named WHATS-3, is a new addition to the WHATS-series samplers and a major upgrade from the previous WHATS-2 sampler with improvements in sample number, valve operational time, physical robustness, and ease of maintenance. Routine laboratory-based pressure tests proved that it is suitable for operation up to 35 MPa pressure. Successful field tests of the new sampler were also carried out in five hydrothermal fields, two in Indian Ocean, and three in Okinawa Trough (max. depth 3,300 m. Relations of Mg and major ion species demonstrated bimodal mixing trends between a hydrothermal fluid and seawater, confirming the high quality of fluids sampled. The newly developed WHATS-3 sampler is well-balanced in sampling capability, field usability, and maintenance feasibility, and can serve as one of the best geofluid samplers available at present to conduct efficient research of deep-sea geofluid systems.

  17. Multipurpose Sediment Passive Sampler with Improved Tissue Mimicry to Measure the Bioavailable Fraction

    Science.gov (United States)

    2016-11-01

    run by HPLC- DAD . There was a linear relationship between the RDX found in the extract and the amount in the solution (Figures 11 and 12, Raw data can...TNT had occurred in the reaction solution. Moreover, the anion is reactive and can form Meisenheimer complexes with electron rich compounds...The poor recovery was determined to be due to the desorption step since it was found that the samplers efficiently extracted the metals from solution

  18. Evaluation and application of a passive air sampler for polycylic aromatic hydrocarbons (PAHs).

    Science.gov (United States)

    Esen, Fatma; Evci, Yildiz M; Tasdemir, Yucel

    2017-08-24

    Sampling of 15 PAHs by the use of both passive air sampler developed (D-PAS) in our research group and PAS (C-PAS) having widespread use in the literature was conducted to compare the performances of the samplers. Sampling was carried out for 1-year period (February 2013-February 2014), in different sampling periods by employing D-PAS and C-PAS. D-PAS and C-PAS were run in parallel for 10, 20, 30, 40 and 60 days. Sampling rates were calculated for both PASs by the use of concentration values obtained from a high-volume air sampler (HVAS). It was determined that calculated sampling values are different from each other by definition of design of C-PAS and D-PAS and difference in environment as velocity of wind and temperature are having different effects upon sampling rates. Collected σ 15 PAHs amounts of 10-day periods in spring, summer, autumn and winter were obtained as 576 ± 333, 209 ± 29, 2402 ± 910 and 664 ± 246 ng for D-PAS and 1070 ± 522, 318 ± 292, 6062 ± 1501 and 6089 ± 4018 ng for C-PAS, respectively. In addition, according to seasons, when collected PAHs in two different samplers were considered, similar results were obtained for the summer time in which no combustion takes place with the aim of domestic heating, while there were differences determined for the seasons with combustion in need of domestic heating. Gas-phase σ 15 PAHs' concentrations were reported depending on seasons in the spring, summer, autumn and winter sequences as 46 ± 32, 9 ± 3, 367 ± 207 and 127 ± 93 ng m -3 for HVAS, respectively.

  19. Pharmaceuticals, alkylphenols and pesticides in Mediterranean coastal waters: Results from a pilot survey using passive samplers

    OpenAIRE

    Munaron, Dominique; Tapie, Nathalie; Budzinski, Helene; Andral, Bruno; Gonzalez, Jean-louis

    2012-01-01

    21 pharmaceuticals, 6 alkylphenols and 27 hydrophilic pesticides and biocides were investigated using polar organic contaminant integrative samplers (POCIS) during a large-scale study of contamination of French Mediterranean coastal waters. Marine and transitional water-bodies, defined under the EU Water Framework Directive were monitored. Our results show that the French Mediterranean coastal waters were contaminated with a large range of emerging contaminants, detected at low concentrations...

  20. Evaluation of polyurethane foam passive air sampler (PUF) as a tool for occupational PAH measurements.

    Science.gov (United States)

    Strandberg, Bo; Julander, Anneli; Sjöström, Mattias; Lewné, Marie; Koca Akdeva, Hatice; Bigert, Carolina

    2018-01-01

    Routine monitoring of workplace exposure to polycyclic aromatic hydrocarbons (PAHs) is performed mainly via active sampling. However, active samplers have several drawbacks and, in some cases, may even be unusable. Polyurethane foam (PUF) as personal passive air samplers constitute good alternatives for PAH monitoring in occupational air (8 h). However, PUFs must be further tested to reliably yield detectable levels of PAHs in short exposure times (1-3 h) and under extreme occupational conditions. Therefore, we compared the personal exposure monitoring performance of a passive PUF sampler with that of an active air sampler and determined the corresponding uptake rates (Rs). These rates were then used to estimate the occupational exposure of firefighters and police forensic specialists to 32 PAHs. The work environments studied were heavily contaminated by PAHs with (for example) benzo(a)pyrene ranging from 0.2 to 56 ng m -3 , as measured via active sampling. We show that, even after short exposure times, PUF can reliably accumulate both gaseous and particle-bound PAHs. The Rs-values are almost independent of variables such as the concentration and the wind speed. Therefore, by using the Rs-values (2.0-20 m 3 day -1 ), the air concentrations can be estimated within a factor of two for gaseous PAHs and a factor of 10 for particulate PAHs. With very short sampling times (1 h), our method can serve as a (i) simple and user-friendly semi-quantitative screening tool for estimating and tracking point sources of PAH in micro-environments and (ii) complement to the traditional active pumping methods. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

    OpenAIRE

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

    2012-01-01

    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...

  2. A critical assessment of passive air samplers for per- and polyfluoroalkyl substances

    Science.gov (United States)

    Karásková, Pavlína; Codling, Garry; Melymuk, Lisa; Klánová, Jana

    2018-07-01

    Since their inclusion in the Stockholm Convention, there has been a need for global monitoring of perfluorooctane sulfonate (PFOS), its salts and perfluorooctanesulfonyl fluoride (PFOSF), along with other non-listed highly fluorinated compounds. Passive air samplers (PAS) are ideal for geographic coverage of atmospheric monitoring. The most common type of PAS, using polyurethane foam (PUF) as a sorbent, was primarily developed for non-polar semivolatile organic compounds (SVOCs) and are not well-validated for polar substances such as the per- and polyfluoroalkyl substances (PFASs), however, they have been used for some PFASs, particularly PFOS. To evaluate their applicability, PAS were deployed for measurement of PFASs in outdoor and indoor air. Outdoors, two types of PAS, one consisting of PUF and one of XAD-2 resin, were deployed in an 18-week calibration study in parallel with a low-volume active air sampler (LV-AAS) in a suburban area. Indoors, PUF-PAS were similarly deployed over 12 weeks to evaluate their applicability for indoor monitoring. Samples were analysed for perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonates (PFSAs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamidoethanols (FOSEs). In outdoor air, 17 out of the 21 PFAS were detected in more than 50% of samples, with a median ∑17PFASs of 18.0 pg m-3 while 20 compounds were detected in indoor air with a median concentration ∑20PFASs of 76.6 pg m-3 using AAS samplers. PFOS was the most common PFAS in the outdoor air while PFBA was most common indoors. Variability between PAS and AAS was observed and comparing gas phase and particle phase separately or in combination did not account for the variation observed. PUF-PAS may still have a valuable use in PFAS monitoring but more work is needed to identify the applicability of passive samplers for ionic PFAS.

  3. Assessment of personal exposure to airborne nanomaterials: Evaluation of a novel sampler

    International Nuclear Information System (INIS)

    Faure, Bertrand; Dozol, Hélène; Brouard, Christophe; Guiot, Arnaud; Clavaguera, Simon

    2017-01-01

    A novel sampler, the NANOBADGE, has been developed to assess personal exposure to nano-objects, agglomerates and aggregates (NOAA) at the workplace. The NANOBADGE collects particles on filters subsequently analyzed by X-Ray Fluorescence spectroscopy (XRF), which provides a mass-based quantification with chemical selectivity. The NANOBADGE was benchmarked against a scanning mobility particle sizer (SMPS) and a DiSCmini by carrying out simultaneous measurements on test aerosols of ZnO or TiO 2 for particle sizes between 20 and 400 nm for which the DiSCmini has its highest accuracy. The effective density and shape of the NOAA present in the test aerosols were determined experimentally to compare number-based data obtained with the SMPS and the DiSCmini with mass-based data obtained with the NANOBADGE. The agreement between the SMPS and the NANOBADGE sampler was within ± 25 % on all test aerosols. The converted DiSCmini data matched the SMPS and sampler data for polydisperse aerosols in the specified size range as long as the DiSCmini assumptions meet the aerosol characteristics (i.e. lognormal size distribution with a given geometric standard deviation σg = 1.9). The detection limits of the NANOBADGE sampler were in the order of tens of nanograms per filter, which is low enough to reliably detect exposure levels below the recommended exposure limit (REL) of the National Institute for Occupational Safety and Health (NIOSH) and the Institut National de Recherche et de Sécurité (INRS) for ultrafine ZnO and TiO 2 even for short-term exposure situations. (paper)

  4. Functions and requirements for the INEL light duty utility arm sampler end effector

    International Nuclear Information System (INIS)

    Pace, D.P.; Barnes, G.E.

    1995-02-01

    This sampler end effector system functions and requirements document defines the system functions that the end effector must perform as well as the requirements the design must meet. Safety, quality assurance, operations, environmental conditions, and regulatory requirements have been considered. The main purpose of this document is to provide a basis for the end effector engineering, design, and fabrication activities. The document shall be the living reference document to initiate the development activities and will be updated as system technologies are finalized

  5. Development of a new passive sampler based on diffusive milligel beads for copper analysis in water.

    Science.gov (United States)

    Perez, M; Reynaud, S; Lespes, G; Potin-Gautier, M; Mignard, E; Chéry, P; Schaumlöffel, D; Grassl, B

    2015-08-26

    A new passive sampler was designed and characterized for the determination of free copper ion (Cu(2+)) concentration in aqueous solution. Each sampling device was composed of a set of about 30 diffusive milligel (DMG) beads. Milligel beads with incorporated cation exchange resin (Chelex) particles were synthetized using an adapted droplet-based millifluidic process. Beads were assumed to be prolate spheroids, with a diameter of 1.6 mm and an anisotropic factor of 1.4. The milligel was controlled in chemical composition of hydrogel (monomer, cross-linker, initiator and Chelex concentration) and characterized in pore size. Two types of sampling devices were developed containing 7.5% and 15% of Chelex, respectively, and 6 nm pore size. The kinetic curves obtained demonstrated the accumulation of copper in the DMG according to the process described in the literature as absorption (and/or adsorption) and release following the Fick's first law of diffusion. For their use in water monitoring, the typical physico-chemical characteristics of the samplers, i.e. the mass-transfer coefficient (k0) and the sampler-water partition coefficient (Ksw), were determined based on a static exposure design. In order to determine the copper concentration in the samplers after their exposure, a method using DMG bead digestion combined to Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES) analysis was developed and optimized. The DMG devices proved to be capable to absorb free copper ions from an aqueous solution, which could be accurately quantified with a mean recovery of 99% and a repeatability of 7% (mean relative uncertainty). Copyright © 2015 Elsevier B.V. All rights reserved.

  6. 1500-year Record of trans-Pacific Dust Flux collected from the Denali Ice Core, Mt. Hunter, Alaska

    Science.gov (United States)

    Saylor, P. L.; Osterberg, E. C.; Koffman, B. G.; Winski, D.; Ferris, D. G.; Kreutz, K. J.; Wake, C. P.; Handley, M.; Campbell, S. W.

    2016-12-01

    Mineral dust aerosols are a critical component of the climate system through their influence on atmospheric radiative forcing, ocean productivity, and surface albedo. Dust aerosols derived from Asian deserts are known to reach as far as Europe through efficient transport in the upper tropospheric westerlies. While centennially-to-millennially resolved Asian dust records exist over the late Holocene from North Pacific marine sediment cores and Asian loess deposits, a high-resolution (sub-annual to decadal) record of trans-Pacific dust flux will significantly improve our understanding of North Pacific dust-climate interactions and provide paleoclimatological context for 20th century dust activity. Here we present an annually resolved 1500-year record of trans-Pacific dust transport based on chemical and physical dust measurements in parallel Alaskan ice cores (208 m to bedrock) collected from the summit plateau of Mt. Hunter in Denali National Park. The cores were sampled at high resolution using a continuous melter system with discrete analyses for major ions (Dionex ion chromatograph), trace elements (Element2 inductively coupled plasma mass spectrometer), and stable water isotope ratios (Picarro laser ringdown spectroscopy), and continuous flow analysis for dust concentration and size distribution (Klotz Abakus). We compare the ice core dust record to instrumental aerosol stations, satellite observations, and dust model data from the instrumental period, and evaluate climatic controls on dust emission and trans-Pacific transport using climate reanalysis data, to inform dust-climate relationships over the past 1500 years. Physical particulate and chemical data demonstrate remarkable fidelity at sub-annual resolution, with both displaying a strong springtime peak consistent with periods of high dust activity over Asian desert source regions. Preliminary results suggest volumetric mode typically ranges from 4.5 - 6.5 um, with a mean value of 5.5 um. Preliminary

  7. State selective reactions of cosmic dust analogues at cryogenic temperatures

    International Nuclear Information System (INIS)

    Perry, James Samuel Anthony

    2001-01-01

    Molecular hydrogen (H 2 ) is the most abundant molecule in interstellar space. It is crucial for initiating all of the chemistry in the Interstellar Medium (ISM) and consequently plays an important role in star formation. However, the amount of H 2 believed to exist in the ISM cannot be accounted for by formation through gas-phase reactions alone. The current, widely accepted theory, is that H 2 forms on the surface of cosmic dust grains. These grains are thought to be composed of amorphous forms of carbon or silicates with temperatures of around 10 K. This thesis describes a new experiment that has been constructed to study H 2 formation on the surface of cosmic dust analogues and presents the initial experimental results. The experiment simulates, through ultra-high vacuum and the use of cryogenics, the conditions of the ISM where cosmic dust grains and H 2 molecules exist. During the experiment, a beam of atomic hydrogen is aimed at a cosmic dust analogue target. H 2 formed on the target's surface is ionised using a laser spectroscopy technique known as Resonance Enhanced Multiphoton lonisation (REMPI) and detected using time-of-flight mass spectrometry. The sensitivity of REMPI is such that H 2 molecules can be ionised in selective internal energy states. This allows the rovibrational populations of the H 2 molecules desorbing from the cosmic dust targets to be determined, providing information on the energy budget of the H 2 formation process in the ISM. Preliminary results from the experiment show that H 2 molecules formed on a diamond-like-carbon surface have a significant non-thermal population of excited vibrational and rotational energy states. (author)

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

    Science.gov (United States)

    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.

  9. Comparison of marine sampling methods for organic contaminants: Passive samplers, water extractions, and live oyster deployment.

    Science.gov (United States)

    Raub, Kristin B; Vlahos, Penny; Whitney, Michael

    2015-08-01

    Laboratory and field trials evaluated the efficacy of three methods of detecting aquatic pesticide concentrations. Currently used pesticides: atrazine, metolachlor, and diazinon and legacy pesticide dieldrin were targeted. Pesticides were extracted using solid-phase extraction (SPE) of water samples, titanium plate passive samplers coated in ethylene vinyl acetate (EVA) and eastern oysters (Crassostrea viginica) as biosamplers. A laboratory study assessed the extraction efficiencies and precision of each method. Passive samplers yielded the highest precision of the three methods (RSD: 3-14% EVA plates; 19-60% oysters; and 25-56% water samples). Equilibrium partition coefficients were derived. A significant relationship was found between the concentration in oyster tissue and the ambient aquatic concentration. In the field (Housatonic River, CT (U.S.)) water sampling (n = 5) detected atrazine at 1.61-7.31 μg L(-1), oyster sampling (n = 2×15) detected dieldrin at n.d.-0.096 μg L(-1) SW and the passive samplers (n = 5×3) detected atrazine at 0.97-3.78 μg L(-1) SW and dieldrin at n.d.-0.68 μg L(-1) SW. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Performance of passive samplers for monitoring estuarine water column concentrations: 2. Emerging contaminants.

    Science.gov (United States)

    Perron, Monique M; Burgess, Robert M; Suuberg, Eric M; Cantwell, Mark G; Pennell, Kelly G

    2013-10-01

    Measuring dissolved concentrations of emerging contaminants, such as polybrominated diphenyl ethers (PBDEs) and triclosan, can be challenging due to their physicochemical properties resulting in low aqueous solubilities and association with particles. Passive sampling methods have been applied to assess dissolved concentrations in water and sediments primarily for legacy contaminants. Although the technology is applicable to some emerging contaminants, the use of passive samplers with emerging contaminants is limited. In the present study, the performance of 3 common passive samplers was evaluated for sampling PBDEs and triclosan. Passive sampling polymers included low-density polyethylene (PE) and polyoxymethylene (POM) sheets, and polydimethylsiloxane (PDMS)-coated solid-phase microextraction (SPME) fibers. Dissolved concentrations were calculated using measured sampler concentrations and laboratory-derived partition coefficients. Dissolved tri-, tetra-, and pentabrominated PBDE congeners were detected at several of the study sites at very low pg/L concentrations using PE and POM. Calculated dissolved water concentrations of triclosan ranged from 1.7 ng/L to 18 ng/L for POM and 8.8 ng/L to 13 ng/L for PE using performance reference compound equilibrium adjustments. Concentrations in SPME were not reported due to lack of detectable chemical in the PDMS polymer deployed. Although both PE and POM were found to effectively accumulate emerging contaminants from the water column, further research is needed to determine their utility as passive sampling devices for emerging contaminants. © 2013 SETAC.

  11. Performance of a hydrostatic sampler for collecting samples at the water-sediment interface in lakes

    Directory of Open Access Journals (Sweden)

    Fernando PEDROZO

    2008-02-01

    Full Text Available The water-sediment interface plays a significant role in the determination of the trophic degree of a waterbody. Numerous redox reactions take place there, resulting in the release of contaminants from the sediments to the water column. The aim of the present work was to develop an equipment for collecting samples from the water-sediment interface. Such equipment was to have a simple design, low construction cost, no depth limitations, and high levels of personal safety and to be reliable in the collection of samples. The performance of the hydrostatic sampler thus developed was tested against samples collected either remotely with a corer or directly with syringes by autonomous divers. The hydrostatic sampler permits access to depths where the costs of the traditional diving methodology are expensive, and where working conditions are dangerous for the diver. The hydrostatic sampler provides an additional means of collecting samples from the water-sediment interface, which together with pore-water samples, facilitates the investigation and understanding of chemical mechanisms in lakes, for instance, those that control the P release from sediment to the water column.

  12. Assessing the transport of PAH in the surficial sediment layer by passive sampler approach.

    Science.gov (United States)

    Belles, Angel; Alary, Claire; Criquet, Justine; Ivanovsky, Anastasia; Billon, Gabriel

    2017-02-01

    A new method based on passive samplers has been developed to assess the diffusive flux of fluorene, fluoranthene and pyrene in the sediment bed and across the sediment-water interface. The dissolved compound concentration gradient in the sediment in the vertical direction was measured at the outlet of a storm water pond by using polyethylene strips as passive samplers. Simultaneously, the dissipation of a set of tracer compounds preloaded in the passive samplers was measured to estimate the effective diffusion coefficients of the pollutants in the sediment. Both measurements were used to evaluate the diffusive flux of the compounds according to Fick's first law. The diffusive fluxes of the 3 studied compounds have been estimated with a centimetre-scale resolution in the upper 44cm of the sediment. According to the higher compound diffusion coefficient and the steeper concentration gradient in the surficial sediment layer, the results show that the net flux of compounds near the sediment interface (1cm depth) is on average 500 times higher than in the deep sediment, with average fluxes at 1cm depth on the order of 5, 0.1 and 0.1ng/m 2 /y for fluorene, fluoranthene and pyrene, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. A new application of passive samplers as indicators of in-situ biodegradation processes.

    Science.gov (United States)

    Belles, Angel; Alary, Claire; Criquet, Justine; Billon, Gabriel

    2016-12-01

    In this paper, a method for evaluating the in-situ degradation of nitro polycyclic aromatic hydrocarbons (nitro-PAH) in sediments is presented. The methodology is adapted from the passive sampler technique, which commonly uses the dissipation rate of labeled compounds loaded in passive sampler devices to sense the environmental conditions of exposure. In the present study, polymeric passive samplers (made of polyethylene strips) loaded with a set of labeled polycyclic aromatic hydrocarbons (PAH) and nitro-PAH were immersed in sediments (in field and laboratory conditions) to track the degradation processes. This approach is theoretically based on the fact that a degradation process induces a steeper concentration gradient of the labeled compounds in the surrounding sediment, thereby increasing their compound dissipation rates compared with their dissipation in abiotic conditions. Postulating that the degradation magnitude is the same for the labeled compounds loaded in polyethylene strips and for their native homologs that are potentially present in the sediment, the field degradation of 3 nitro-PAH (2-nitro-fluorene, 1-nitro-pyrene, 6-nitro-chrysene) was semi-quantitatively analyzed using the developed method. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Assessment the impact of samplers change on the uncertainty related to geothermalwater sampling

    Science.gov (United States)

    Wątor, Katarzyna; Mika, Anna; Sekuła, Klaudia; Kmiecik, Ewa

    2018-02-01

    The aim of this study is to assess the impact of samplers change on the uncertainty associated with the process of the geothermal water sampling. The study was carried out on geothermal water exploited in Podhale region, southern Poland (Małopolska province). To estimate the uncertainty associated with sampling the results of determinations of metasilicic acid (H2SiO3) in normal and duplicate samples collected in two series were used (in each series the samples were collected by qualified sampler). Chemical analyses were performed using ICP-OES method in the certified Hydrogeochemical Laboratory of the Hydrogeology and Engineering Geology Department at the AGH University of Science and Technology in Krakow (Certificate of Polish Centre for Accreditation No. AB 1050). To evaluate the uncertainty arising from sampling the empirical approach was implemented, based on double analysis of normal and duplicate samples taken from the same well in the series of testing. The analyses of the results were done using ROBAN software based on technique of robust statistics analysis of variance (rANOVA). Conducted research proved that in the case of qualified and experienced samplers uncertainty connected with the sampling can be reduced what results in small measurement uncertainty.

  15. Assessment of benthic macroinvertebrates at Nile tilapia production using artificial substrate samplers

    Directory of Open Access Journals (Sweden)

    M. S. G. Moura e Silva

    Full Text Available Abstract Biomonitoring is a cheap and effective tool for evaluation of water quality, and infer on the balance of aquatic ecosystems. The benthic macroinvertebrates are bioindicators sensitive to environmental changes, and can assist in detecting and preventing impacts such as organic enrichment and imbalance in the food chain. We compared the structure of benthic communities on artificial substrate samplers located in places near and far from net cages for production of Nile tilapia (Oreochromis niloticus. Samplers were manufactured with nylon net, using substrates such as crushed stone, gravel, loofah and cattail leaves. Samples were collected after 30 days of colonization, rinsed and then the specimens were identified and quantified. The following metrics were calculated: richness of Operational Taxonomic Units, Margalef richness, abundance of individuals, Shannon index and evenness index. The macrobenthic community structure was strongly modified according to the proximity of the net cages. Metrics showed significant differences (p < 0.05 between near and distant sites, for both periods (dry and rainy seasons. The position of the samplers significantly affected the structure of macroinvertebrate community, as near sites showed higher values for the community metrics, such as richness and diversity. Near sites presented a larger number of individuals, observed both in the dry and rainy seasons, with a predominance of Chironomidae (Diptera in the dry season and Tubificidae (Oligochaeta in the rainy season.

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

    International Nuclear Information System (INIS)

    Bartkow, Michael E.; Kennedy, Karen E.; Huckins, James N.; Holling, Neil; Komarova, Tatiana; Mueller, Jochen 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. - Photodegradation/loss of PAHs occurs from passive air samplers (SPMDs) deployed in various sampler chambers

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 NO x 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 NO x 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. - Highlights: • NO x concentrations in four adjacent counties were higher than the Mecklenburg site. • Ozone concentrations showed little county to county variation. • Passive samplers and community science can extend the air quality monitoring network. • Community science increases community awareness of air quality issues. - Regional community air quality monitoring is important in educating communities about air quality science issues that can impact personal health and behavior

  18. Cosmic dust investigations. Pt. 2

    International Nuclear Information System (INIS)

    Simpson, J.A.; Tuzzolino, A.J.

    1989-01-01

    A series of experiments have been completed using accelerator dust particles in the mass range ≅ 10 -9 -10 -6 g and velocity range ≅ 2-12 km/s to measure the velocity loss and degree of fragmentation for dust particles penetrating 6 and 28 μm thick polyvinylidene fluoride (PVDF) dust detectors. These measurements prove that even for a ratio of PVDF foil thickness to particle diameter as large as 0.6, the velocity loss and fragmentation is far less than expected from earlier reports in the literature. For 6 μm thick foils the velocity loss is ≤5%. These experiments are based on an extension of our earlier work which showed that two PVDF foils spaced a given distance apart could provide accurate time-of-flight (TOF) information due to the fast pulse rise time of PVDF detector response. We also report on our present state of development of PVDF position-sensing detectors which identify the x, y coordinates of particle impact, using detector and electronic pulse techniques adapted from our semiconductor position-sensing cosmic-ray detectors. Typical position errors of ≅ 1 mm are readily achieved. Finally, we have combined the above developments into a dust-particle telescope which accurately (≅ 1 0 angular accuracy) measures the trajectory of the incident particle as well as its mass and incident velocity, irrespective of whether it is a charged or neutral particle. We discuss how this practical dust telescope can be combined with dust capture cells for space flight and later recovery for laboratory determination of elemental and isotopic composition of captured dust. We also describe a simpler trajectory array based on discrete mosaics of thin detectors which would measure trajectories with a mean angular error of ≅ 4 0 . We discuss the application of these instruments for distinguishing between interplanetary dust of cometary and asteroidal origin, and for measurements on a space station, from near-Earth trapped dust of artificial origin. (orig.)

  19. Charged dust in saturn's magnetosphere

    International Nuclear Information System (INIS)

    Mendis, D.A.; Hill, J.R.; Houpis, H.L.F.

    1983-01-01

    Gravito-electrodynamic theory of charged dust grains is used to explain a variety of phenomena in those portions of the Saturnian ring system that are known to be dominated by fine (micron- and submicron-sized) dust, and in which collisional forces and Coulomb drag can be neglected. Among the phenomena discussed are the formation and evolution of the rotating near-radial spokes in the B-ring, the formation of waves in the F-ring, the cause of eccentricities of certain isolated ringlets, and the origin and morphology of the broad diffuse E-ring. Several novel processes predicted by the gravitoelectrodynamic theory, including 'magneto-gravitational capture' of exogenic dust by the magnetosphere, '1:1 magneto-gravitational orbital resonances' of charged dust with nearby satellites, and 'gyro-orbital resonances,' are used to explain individual observations. The effect of a ring current associated with this charged dust is also evaluated. Finally, the cosmogonic implications of the magneto-gravitational theory are briefly discussed. While several (although not all) of these processes have been discussed by one or more of the present authors elsewhere, the purpose of this paper is to synthesize all these processes within the framework of gravito-electrodynamics, and also to show its range of applicability within Saturn's ring system

  20. Spring Dust Storm Smothers Beijing

    Science.gov (United States)

    2002-01-01

    A few days earlier than usual, a large, dense plume of dust blew southward and eastward from the desert plains of Mongolia-quite smothering to the residents of Beijing. Citizens of northeastern China call this annual event the 'shachenbao,' or 'dust cloud tempest.' However, the tempest normally occurs during the spring time. The dust storm hit Beijing on Friday night, March 15, and began coating everything with a fine, pale brown layer of grit. The region is quite dry; a problem some believe has been exacerbated by decades of deforestation. According to Chinese government estimates, roughly 1 million tons of desert dust and sand blow into Beijing each year. This true-color image was made using two adjacent swaths (click to see the full image) of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on March 17, 2002. The massive dust storm (brownish pixels) can easily be distinguished from clouds (bright white pixels) as it blows across northern Japan and eastward toward the open Pacific Ocean. The black regions are gaps between SeaWiFS' viewing swaths and represent areas where no data were collected. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  1. Physical properties of five grain dust types.

    Science.gov (United States)

    Parnell, C B; Jones, D D; Rutherford, R D; Goforth, K J

    1986-01-01

    Physical properties of grain dust derived from five grain types (soybean, rice, corn, wheat, and sorghum) were measured and reported. The grain dusts were obtained from dust collection systems of terminal grain handling facilities and were assumed to be representative of grain dust generated during the handling process. The physical properties reported were as follows: particle size distributions and surface area measurements using a Coulter Counter Model TAII; percent dust fractions less than 100 micron of whole dust; bulk density; particle density; and ash content. PMID:3709482

  2. Dust Storm over the Middle East: Retrieval Approach, Source Identification, and Trend Analysis

    Science.gov (United States)

    Moridnejad, A.; Karimi, N.; Ariya, P. A.

    2014-12-01

    The Middle East region has been considered to be responsible for approximately 25% of the Earth's global emissions of dust particles. By developing Middle East Dust Index (MEDI) and applying to 70 dust storms characterized on MODIS images and occurred during the period between 2001 and 2012, we herein present a new high resolution mapping of major atmospheric dust source points participating in this region. To assist environmental managers and decision maker in taking proper and prioritized measures, we then categorize identified sources in terms of intensity based on extracted indices for Deep Blue algorithm and also utilize frequency of occurrence approach to find the sensitive sources. In next step, by implementing the spectral mixture analysis on the Landsat TM images (1984 and 2012), a novel desertification map will be presented. The aim is to understand how human perturbations and land-use change have influenced the dust storm points in the region. Preliminary results of this study indicate for the first time that c.a., 39 % of all detected source points are located in this newly anthropogenically desertified area. A large number of low frequency sources are located within or close to the newly desertified areas. These severely desertified regions require immediate concern at a global scale. During next 6 months, further research will be performed to confirm these preliminary results.

  3. Glass Frit Clumping And Dusting

    International Nuclear Information System (INIS)

    Steimke, J. L.

    2013-01-01

    DWPF mixes a slurry of glass frit (Frit 418) and dilute (1.5 wt%) formic acid solution with high level waste in the Slurry Mix Evaporator (SME). There would be advantages to introducing the frit in a non-slurry form to minimize water addition to the SME, however, adding completely dry frit has the potential to generate dust which could clog filters or condensers. Prior testing with another type of frit, Frit 320, and using a minimal amount of water reduced dust generation, however, the formation of hard clumps was observed. To examine options and behavior, a TTQAP [McCabe and Stone, 2013] was written to initiate tests that would address these concerns. Tests were conducted with four types of glass frit; Frit 320, DWPF Frit 418, Bekeson Frit 418 and Multi-Aspirator Frit 418. The last two frits are chemically identical to DWPF Frit 418 but smaller particles were removed by the respective vendors. Test results on Frit Clumping and Dusting are provided in this report. This report addresses the following seven questions. Short answers are provided below with more detailed answers to follow. 1. Will the addition of a small amount of water, 1.5 wt%, to dry DWPF Frit 418 greatly reduce the dust generation during handling at DWPF? a. Yes, a small scale test showed that adding a little water to the frit greatly reduced dust generation during handling. 2. Will the addition of small amounts of water to the frit cause clumping that will impair frit handling at DWPF? a. No, not with Frit 418. Although clumps were observed to form when 1.5 wt% water was mixed with DWPF Frit 418, then compressed and air-dried overnight, the clumps were easily crushed and did not form the hardened material noted when Frit 320 was tested. 3. What is the measured size distribution of dust generated when dry frit is handled? (This affects the feasibility and choice of processing equipment for removing the dust generating fraction of the frit before it is added to the SME.) a. The size distribution for

  4. Glass Frit Clumping And Dusting

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J. L.

    2013-09-26

    DWPF mixes a slurry of glass frit (Frit 418) and dilute (1.5 wt%) formic acid solution with high level waste in the Slurry Mix Evaporator (SME). There would be advantages to introducing the frit in a non-slurry form to minimize water addition to the SME, however, adding completely dry frit has the potential to generate dust which could clog filters or condensers. Prior testing with another type of frit, Frit 320, and using a minimal amount of water reduced dust generation, however, the formation of hard clumps was observed. To examine options and behavior, a TTQAP [McCabe and Stone, 2013] was written to initiate tests that would address these concerns. Tests were conducted with four types of glass frit; Frit 320, DWPF Frit 418, Bekeson Frit 418 and Multi-Aspirator Frit 418. The last two frits are chemically identical to DWPF Frit 418 but smaller particles were removed by the respective vendors. Test results on Frit Clumping and Dusting are provided in this report. This report addresses the following seven questions. Short answers are provided below with more detailed answers to follow. 1. Will the addition of a small amount of water, 1.5 wt%, to dry DWPF Frit 418 greatly reduce the dust generation during handling at DWPF? a. Yes, a small scale test showed that adding a little water to the frit greatly reduced dust generation during handling. 2. Will the addition of small amounts of water to the frit cause clumping that will impair frit handling at DWPF? a. No, not with Frit 418. Although clumps were observed to form when 1.5 wt% water was mixed with DWPF Frit 418, then compressed and air-dried overnight, the clumps were easily crushed and did not form the hardened material noted when Frit 320 was tested. 3. What is the measured size distribution of dust generated when dry frit is handled? (This affects the feasibility and choice of processing equipment for removing the dust generating fraction of the frit before it is added to the SME.) a. The size distribution for

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

    Science.gov (United States)

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

    2017-08-01

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

  6. CV-Dust: Atmospheric aerosol in the Cape Verde region: carbon and soluble fractions of PM10

    Science.gov (United States)

    Pio, C.; Nunes, T.; Cardoso, J.; Caseiro, A.; Custódio, D.; Cerqueira, M.; Patoilo, D.; Almeida, S. M.; Freitas, M. C.

    2012-04-01

    than 100 PM10 samples, addressing mainly their mass concentrations and the chemical composition of water soluble ions and carbon species (carbonates and organic and elemental carbon). Different PM10 samplers worked simultaneously in order to collect enough mass to make the aerosol characterization through the different methodologies and to collect aerosols in different filter matrixes, which have to be appropriated to the chemical and mineralogical analysis. The sampling site was located at Santiago Island, in the surroundings of Praia City (14° 55' N e 23° 29' W, 98 m at sea level). High concentrations, up to more than 400 μg m-3, are connected to north-east and north-northeast winds, and it was identified several dust events characteristic of "bruma seca", whose duration is on average of two to four days. Backward trajectories analysis confirms that the high concentrations in Cape Verde are associated with air masses passing over the Sahara. During dust events the percentage of inorganic water soluble ions for the total PM10 mass concentration decreased significantly to values lower than 10% in comparison with remainder data that range around 45±10%. Acknowledgement: This work was funded by the Portuguese Science Foundation (FCT) through the project PTDD/AAC-CLI/100331/2008 and FCOMP-01-0124-FEDER-008646 (CV-Dust). J. Cardoso acknowledges the PhD grant SFRH-BD-6105-2009 from FCT.

  7. Dust deposit in recirculation regions

    International Nuclear Information System (INIS)

    Griemert, R.

    1985-03-01

    The present report shows investigations, which have been carried out in a closed duct at forward and backward facing steps. Distribution of fluid velocity and fluid fluctuations in and normal to main flow direction as well as the distribution of Reynolds shear stress have been measured. The mass transfer downstream of a backward facing step has been investigated as well. By using graphite-, copper-, tin- and rubber dust, conditions of deposition have been defined experimentally. A serie of photos shows the filling of a recirculation region downstream of a backward facing step with graphite dust. The present investigations allow to avoid deposition of dust in recirculation regions by selecting the fluid numbers in an appropriate way. (orig.) [de

  8. Dust Storm Hits Canary Islands

    Science.gov (United States)

    2002-01-01

    A thick pall of sand and dust blew out from the Sahara Desert over the Atlantic Ocean yesterday (January 6, 2002), engulfing the Canary Islands in what has become one of the worst sand storms ever recorded there. In this scene, notice how the dust appears particularly thick in the downwind wake of Tenerife, the largest of the Canary Islands. Perhaps the turbulence generated by the air currents flowing past the island's volcanic peaks is churning the dust back up into the atmosphere, rather than allowing it to settle toward the surface. This true-color image was captured by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on January 7, 2002. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  9. Mechanisms of metal dusting corrosion

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo

    In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... deformed stainless steel flakes is transformed to expanded martensite/austenite during low-temperature carburization. Various experimental procedures to experimentally determine the concentration dependent diffusion coefficient of carbon in expanded austenite are evaluated. The most promising procedure...... powders and flakes. The nature of the decomposition products, carbides of the form M23C6 and M7C3, were evaluated by X-ray diffraction, light optical microscopy, scanning electron microscopy and thermodynamic modelling. The decomposition was found to be dependent on several parameters such as thermal...

  10. The Effects of Bit Wear on Respirable Silica Dust, Noise and Productivity: A Hammer Drill Bench Study.

    Science.gov (United States)

    Carty, Paul; Cooper, Michael R; Barr, Alan; Neitzel, Richard L; Balmes, John; Rempel, David

    2017-07-01

    Hammer drills are used extensively in commercial construction for drilling into concrete for tasks including rebar installation for structural upgrades and anchor bolt installation. This drilling task can expose workers to respirable silica dust and noise. The aim of this pilot study was to evaluate the effects of bit wear on respirable silica dust, noise, and drilling productivity. Test bits were worn to three states by drilling consecutive holes to different cumulative drilling depths: 0, 780, and 1560 cm. Each state of bit wear was evaluated by three trials (nine trials total). For each trial, an automated laboratory test bench system drilled 41 holes 1.3 cm diameter, and 10 cm deep into concrete block at a rate of one hole per minute using a commercially available hammer drill and masonry bits. During each trial, dust was continuously captured by two respirable and one inhalable sampling trains and noise was sampled with a noise dosimeter. The room was thoroughly cleaned between trials. When comparing results for the sharp (0 cm) versus dull bit (1560 cm), the mean respirable silica increased from 0.41 to 0.74 mg m-3 in sampler 1 (P = 0.012) and from 0.41 to 0.89 mg m-3 in sampler 2 (P = 0.024); levels above the NIOSH recommended exposure limit of 0.05 mg m-3. Likewise, mean noise levels increased from 112.8 to 114.4 dBA (P < 0.00001). Drilling productivity declined with increasing wear from 10.16 to 7.76 mm s-1 (P < 0.00001). Increasing bit wear was associated with increasing respirable silica dust and noise and reduced drilling productivity. The levels of dust and noise produced by these experimental conditions would require dust capture, hearing protection, and possibly respiratory protection. The findings support the adoption of a bit replacement program by construction contractors. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  11. Intergalactic dust and quasar distribution

    International Nuclear Information System (INIS)

    Soltan, A.

    1979-01-01

    Non-homogeneous intergalactic extinction may considerably affect the quasar distribution. Especially samples of quasars isolated on the basis of B-V colours are subject to this phenomenon. Apparent grouping and close pairs of quasars reported in the literature may be a result of intergalactic dust. Using surface distribution of faint blue objects selected by Hawkins and Reddish it is estimated that intergalactic extinction in B should reach approximately 1 mag out to the redshift of approximately 1. This is slightly larger than predicted by theory and comparable to the mean dust density derived from observations. (Author)

  12. Technical note: Mineralogical, chemical, morphological, and optical interrelationships of mineral dust re-suspensions

    Directory of Open Access Journals (Sweden)

    J. P. Engelbrecht

    2016-08-01

    Full Text Available This paper promotes an understanding of the mineralogical, chemical, and physical interrelationships of re-suspended mineral dusts collected as grab samples from global dust sources. Surface soils were collected from arid regions, including the southwestern USA, Mali, Chad, Morocco, Canary Islands, Cabo Verde, Djibouti, Afghanistan, Iraq, Kuwait, Qatar, UAE, Serbia, China, Namibia, Botswana, Australia, and Chile. The  <  38 µm sieved fraction of each sample was re-suspended in a chamber, from which the airborne mineral dust could be extracted, sampled, and analyzed. Instruments integrated into the entrainment facility included two PM10 and two PM2.5 filter samplers, a beta attenuation gauge for the continuous measurement of PM10 and PM2.5 particulate mass fractions, an aerodynamic particle size analyzer, and a three-wavelength (405, 532, 781 nm photoacoustic instrument with integrating reciprocal nephelometer for monitoring absorption and scattering coefficients during the dust re-suspension process. Filter sampling media included Teflon® membrane and quartz fiber filters for chemical analysis and Nuclepore® filters for individual particle analysis by scanning electron microscopy (SEM. The  <  38 µm sieved fractions were also analyzed by X-ray diffraction for their mineral content while the  >  75,  <  125 µm soil fractions were mineralogically assessed by optical microscopy. Presented here are results of the optical measurements, showing the interdependency of single-scattering albedos (SSA at three different wavelengths and mineralogical content of the entrained dust samples. To explain the elevated concentrations of iron (Fe and Fe ∕ Al ratios in the soil re-suspensions, we propose that dust particles are to a large extent composed of nano-sized particles of micas, clays, metal oxides, and ions of potassium (K+, calcium (Ca2+, and sodium (Na+ evenly dispersed as a colloid or adsorbed in amorphous

  13. Electrostatic Dust Detector with Improved Sensitivity

    International Nuclear Information System (INIS)

    Boyle, D.P.; Skinner, C.H.; Roquemore, A.L.

    2008-01-01

    Methods to measure the inventory of dust particles and to remove dust if it approaches safety limits will be required in next-step tokamaks such as ITER. An electrostatic dust detector, based on a fine grid of interlocking circuit traces, biased to 30 or 50 V, has been developed for the detection of dust on remote surfaces in air and vacuum environments. Gaining operational experience of dust detection on surfaces in tokamaks is important, however the level of dust generated in contemporary short-pulse tokamaks is comparatively low and high sensitivity is necessary to measure dust on a shot-by-shot basis. We report on modifications in the detection electronics that have increased the sensitivity of the electrostatic dust detector by a factor of up to 120, - a level suitable for measurements on contemporary tokamaks.

  14. Infrared Observations of Cometary Dust and Nuclei

    Science.gov (United States)

    Lisse, Carey

    2004-01-01

    This bibliography lists citations for publications published under the grant. Subjects of the publications include cometary dust, instellar and interplanetary dust, comet nuclei and comae, Comet Hale-Bopp, infrared observations of comets, mass loss, and comet break-up.

  15. The global distribution of mineral dust

    International Nuclear Information System (INIS)

    Tegen, I; Schepanski, K

    2009-01-01

    Dust aerosol particles produced by wind erosion in arid and semi arid regions affect climate and air quality, but the magnitude of these effects is largely unquantified. The major dust source regions include the Sahara, the Arabian and Asian deserts; global annual dust emissions are currently estimated to range between 1000 and 3000 Mt/yr. Dust aerosol can be transported over long distances of thousands of kilometers, e.g. from source regions in the Saharan desert over the North Atlantic, or from the Asian deserts towards the Pacific Ocean. The atmospheric dust load varies considerably on different timescales. While dust aerosol distribution and dust effects are important on global scales, they strongly depend on dust emissions that are controlled on small spatial and temporal scales.

  16. Exact solutions for rotating charged dust

    International Nuclear Information System (INIS)

    Islam, J.N.

    1984-01-01

    Earlier work by the author on rotating charged dust is summarized. An incomplete class of exact solutions for differentially rotating charged dust in Newton-Maxwell theory for the equal mass and charge case that was found earlier is completed. A new global exact solution for cylindrically symmetric differentially rotating charged dust in Newton-Maxwell theory is presented. Lastly, a new exact solution for cylindrically symmetric rigidly rotating charged dust in general relativity is given. (author)

  17. Studies of dust shells around stars

    International Nuclear Information System (INIS)

    Bedijn, P.J.

    1977-01-01

    This thesis deals with some aspects of circumstellar dust shells. This dust shell, emitting infrared radiation, is described by way of its absorptive and emissive properties as well as by the transfer of radiation through the dust shell itself. Model calculations are compared to experimental results and agree reasonably well. The author also discusses the dynamics of the extended shells of gas and dust around newly formed stars

  18. Airborne radioiodine species sampler and it's application for measuring removal efficiencies of large charcoal adsorbers for ventilation exhaust air

    International Nuclear Information System (INIS)

    Emel, D.; Hetzer, D.; Pelletier, C.A.; Barefoot, E.D.; Cline, J.E.

    1976-01-01

    A program, sponsored by the Electric Power Research Institute, is underway to determine the chemical species of radioiodine coming from LWR power plants and their persistence in the nearby environment. In support of this program, an airborne radioiodine sampler, developed and used by the AEC was modified and tested. This sampler consists of five components. The components are: (1) a particulate filter, (2) CdI 2 on a matrix of chromosorb-P to retain I 2 , (3) 4-Iodophenol on a matrix of activated alumina to retain HOI, (4) silver exchanged molecular sieve-13X to retain organic iodides, and (5) impregnated charcoal to serve as a control. The AEC sampler has not been proof-tested for periods over 48 hours or for flow rates above 0.10 l/s. For maximum sensitivity, a sampler is required to be used for periods of one to two weeks and at a flow rate giving a bed residence time of 0.1 sec. The AEC sampler was scaled up in size to attain an air sampling rate of 0.9 l/s. Each media for this sampler (except the particulate filter) was tested in the laboratory for retention of the iodine species; I 2 , Organic, and HOI. The tests were conducted at typical conditions observed at the main iodine release points at nuclear power plants. Confirmatory tests were run at operating nuclear power plants. The test results showed that under normal plant conditions the sampler could be operated at flow rates up to 0.80 l/s and differentiate the iodine species I 2 , HOI, and CH 3 I. The retention efficiencies of each media for its specie of radioiodine were found to be: I 2 on CdI 2 - 87 +- 5%, HOI on IPH 94 +- 4%, and CH 3 I on Ag 13-X or KI charcoal 99 +- 1%

  19. Development of polyurethane-based passive samplers for ambient monitoring of urban-use insecticides in water.

    Science.gov (United States)

    Liao, Chunyang; Richards, Jaben; Taylor, Allison R; Gan, Jay

    2017-12-01

    Widespread use of insecticides for the control of urban pests such as ants, termites, and spiders has resulted in contamination and toxicity in urban aquatic ecosystems in different regions of the world. Passive samplers are a convenient and integrative tool for in situ monitoring of trace contaminants in surface water. However, the performance of a passive sampler depends closely on its affinity for the target analytes, making passive samplers highly specific to the types of contaminants being monitored. The goal of this study was to develop a passive sampler compatible with a wide range of insecticides, including the strongly hydrophobic pyrethroids and the weakly hydrophobic fipronil and organophosphates. Of six candidate polymeric thin films, polyurethane film (PU) was identified to be the best at enriching the test compounds. The inclusion of stable isotope labeled analogs as performance reference compounds (PRCs) further allowed the use of PU film for pyrethroids under non-equilibrium conditions. The PU sampler was tested in a large aquarium with circulatory water flow, and also deployed at multiple sites in surface streams in southern California. The concentrations of pesticides derived from the PU sampler ranged from 0.5 to 18.5 ng/L, which were generally lower than the total chemical concentration measured by grab samples, suggesting that suspended particles and dissolved organic matter in water rendered them less available. The influence of suspended particles and dissolved organic matter on bioavailability was more pronounced for pyrethroids than for fipronils. The results show that the developed PU film sampler, when coupled with PRCs, may be used for rapid and sensitive in-situ monitoring of a wide range of insecticides in surface water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. New Rhizon in situ sampler for pore water studies in aquatic sediments: For example nutrient input from submarine groundwater discharge in costal areas.

    OpenAIRE

    Seeberg-Elverfeldt, J.; Schlüter, Michael; Kölling, M.; Feseker, T.

    2005-01-01

    To investigate coastal biogeochemical cycles, especially at the sediment/water interface,improved sampling methods are necessary. For this purpose, we developed apore water in situ sampler with miniature sampling devices, so called Rhizons. Rhizonsoil moisture samplers have been used as sampling devices in unsaturated soilsfor the last ten years. In aquatic science they have been rarely used to extract porewater from sediments. This study presents a new developed Rhizon In Situ Sampler(RISS) ...

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

    Science.gov (United States)

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

    2013-10-01

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

  2. Radio frequency discharge with dust particles

    NARCIS (Netherlands)

    Chutov, Y. I.; W. J. Goedheer,; Kravchenko, O. Y.; Zuz, V. M.; Yan, M.; Martins, R.; Ferreira, I.; Fortunato, E.; Kroesen, G.

    2000-01-01

    A 1D PIC/MCC method has been developed for computer simulations of low-pressure RF discharges with dust particles using the method for dust-free discharges. A RF discharge in argon with dust particles distributed uniformly in the interelectrode gap is simulated at parameters providing a possibility

  3. Thirteen years of Aeolian dust dynamics in a desert region (Negev desert, Israel): analysis of horizontal and vertical dust flux, vertical dust distribution and dust grain size

    NARCIS (Netherlands)

    Offer, Z.Y.; Goossens, D.

    2004-01-01

    At Sede Boqer (northern Negev desert, Israel), aeolian dust dynamics have been measured during the period 1988–2000. This study focuses on temporal records of the vertical and horizontal dust flux, the vertical distribution of the dust particles in the atmosphere, and the grain size of the

  4. Dust Measurements Onboard the Deep Space Gateway

    Science.gov (United States)

    Horanyi, M.; Kempf, S.; Malaspina, D.; Poppe, A.; Srama, R.; Sternovsky, Z.; Szalay, J.

    2018-02-01

    A dust instrument onboard the Deep Space Gateway will revolutionize our understanding of the dust environment at 1 AU, help our understanding of the evolution of the solar system, and improve dust hazard models for the safety of crewed and robotic missions.

  5. Properties of interstellar dust in reflection nebulae

    International Nuclear Information System (INIS)

    Sellgren, K.

    1988-01-01

    Observations of interstellar dust in reflection nebulae are the closest analog in the interstellar medium to studies of cometary dust in our solar system. The presence of a bright star near the reflection nebula dust provides the opportunity to study both the reflection and emission characteristics of interstellar dust. At 0.1 to 1 micrometer, the reflection nebula emission is due to starlight scattered by dust. The albedo and scattering phase function of the dust is determined from observations of the scattered light. At 50 to 200 micrometers, thermal emission from the dust in equilibrium with the stellar radiation field is observed. The derived dust temperature determines the relative values of the absorption coefficient of the dust at wavelengths where the stellar energy is absorbed and at far infrared wavelengths where the absorbed energy is reradiated. These emission mechanisms directly relate to those seen in the near and mid infrared spectra of comets. In a reflection nebula the dust is observed at much larger distances from the star than in our solar system, so that the equilibrium dust temperature is 50 K rather than 300 K. Thus, in reflection nebulae, thermal emission from dust is emitted at 50 to 200 micrometer

  6. House dust extracts contain potent immunological adjuvants

    NARCIS (Netherlands)

    Beukelman, C.J.; Dijk, H. van; Aerts, P.C.; Rademaker, P.M.; Berrens, L.; Willers, J.M.N.

    1987-01-01

    A crude aqueous extract of house dust and two house dust subfractions were tested for adjuvant activity in a sensitivity assay performed in mice. Evidence is presented that house dust contains at least two potent immunological adjuvants. One of these, present in both subfractions, was probably

  7. A Standard Characterization Methodology for Respirable Coal Mine Dust Using SEM-EDX

    Directory of Open Access Journals (Sweden)

    Rachel Sellaro

    2015-12-01

    Full Text Available A key consideration for responsible development of mineral and energy resources is the well-being of workers. Respirable dust in mining environments represents a serious concern for occupational health. In particular, coal miners can be exposed to a variety of dust characteristics depending on their work activities, and some exposures may pose risk for lung diseases like CWP and silicosis. As underscored by common regulatory frameworks, respirable dust exposures are generally characterized on the basis of total mass concentration, and also the silica mass fraction. However, relatively little emphasis has been placed on other dust characteristics that may be important in terms of identifying health risks. Comprehensive particle-level analysis to estimate chemistry, size, and shape distributions of particles is possible. This paper describes a standard methodology for characterization of respirable coal mine dust using scanning electron microscopy (SEM with energy dispersive X-ray (EDX. Preliminary verification of the method is shown based several dust samples collected from an underground mine in Central Appalachia.

  8. Toxicity of Lunar Dust in Lungs Assessed by Examining Biomarkers in Exposed Mice

    Science.gov (United States)

    Lam, C.-W.; James, J. T.; Zeidler-Erdely, P. C.; Castranova, V.; Young, S. H.; Quan, C. L.; Khan-Mayberry, N.; Taylor, L. A.

    2010-01-01

    NASA is contemplating to build an outpost on the Moon for prolonged human habitation and research. The lunar surface is covered by a layer of soil, of which the finest portion is highly reactive dust. Dust samples of respirable sizes were aerodynamically isolated from two lunar soil samples of different maturities (cosmic exposure ages) collected during the Apollo 16 mission. The lunar dust samples, TiO2, or quartz, suspended in normal saline were given to groups of 5 C57 male mice by intrapharyngeal aspiration at 0. 1, 0.3, or 1.0 mg/mouse. Because lunar dust aggregates rapidly in aqueous media, some tests were conducted with dusts suspended in Survanta/saline (1:1). The mice were euthanized 7 or 30 days later, and their lungs were lavaged to assess the presence of toxicity biomarkers in bronchioalveolar lavage fluids. The overall results showed that the two lunar dust samples were similar in toxicity, they were more toxic than T102 , but less toxic than quartz. This preliminary study is a part of the large study to obtain data for setting exposure limits for astronauts living on the Moon

  9. Observed spectral features of dust

    International Nuclear Information System (INIS)

    Willner, S.P.

    1984-01-01

    The author concentrates on the observed properties of dust spectral features. Identifications, based on laboratory data, are given whenever plausible ones exist. There are a very large number of papers in the literature of even such a young field as infrared spectroscopy, and therefore the author refers only to the most recent paper on a topic or to another review. (Auth.)

  10. Meteors, meteorites and cosmic dust

    International Nuclear Information System (INIS)

    Lebedinets, V.N.

    1987-01-01

    The problem of meteorite origin and meteorite composition is discussed. Nowadays, most scientists suppose that the giant Oort cloud consisting of ice comet nuclei is the sourse of the meteor matter. A principle unity of the matter of meteorites falling to the Earth and cosmic dust is noted as well as that of meteorite bodies evaporating in the atmosphere and bearing meteors and bodies

  11. Occupational diseases of dust etiology

    International Nuclear Information System (INIS)

    Sokolik, L.I.; Shkondin, A.N.

    1981-01-01

    Detailed etiologic and clinico-roentgenological characteristics of pneumoconiosis, as widely spread occupational disease caused by different kinds of dust, are given. The course of pneumoconiosis is discussed depending on working conditions of patients after the disease had been ascertained, as well as its complications, taking into account roentgeno-morphological types of fibrosis and the stages of the disease [ru

  12. 75 FR 32142 - Combustible Dust

    Science.gov (United States)

    2010-06-07

    .... Contact Mat Chibbaro, P.E., Fire Protection Engineer, Office of Safety Systems, OSHA Directorate of..., and metals (such as aluminum and magnesium). Industries that may have combustible dust hazards include..., chemical manufacturing, textile manufacturing, furniture manufacturing, metal processing, fabricated metal...

  13. Trapping Dust to Form Planets

    Science.gov (United States)

    Kohler, Susanna

    2017-10-01

    Growing a planet from a dust grain is hard work! A new study explores how vortices in protoplanetary disks can assist this process.When Dust Growth FailsTop: ALMA image of the protoplanetary disk of V1247 Orionis, with different emission components labeled. Bottom: Synthetic image constructed from the best-fit model. [Kraus et al. 2017]Gradual accretion onto a seed particle seems like a reasonable way to grow a planet from a grain of dust; after all, planetary embryos orbit within dusty protoplanetary disks, which provides them with plenty of fuel to accrete so they can grow. Theres a challenge to this picture, though: the radial drift problem.The radial drift problem acknowledges that, as growing dust grains orbit within the disk, the drag force on them continues to grow as well. For large enough dust grains perhaps around 1 millimeter the drag force will cause the grains orbits to decay, and the particles drift into the star before they are able to grow into planetesimals and planets.A Close-Up Look with ALMASo how do we overcome the radial drift problem in order to form planets? A commonly proposed mechanism is dust trapping, in which long-lived vortices in the disk trap the dust particles, preventing them from falling inwards. This allows the particles to persist for millions of years long enough to grow beyond the radial drift barrier.Observationally, these dust-trapping vortices should have signatures: we would expect to see, at millimeter wavelengths, specific bright, asymmetric structures where the trapping occurs in protoplanetary disks. Such disk structures have been difficult to spot with past instrumentation, but the Atacama Large Millimeter/submillimeter Array (ALMA) has made some new observations of the disk V1247 Orionis that might be just what were looking for.Schematic of the authors model for the disk of V1247 Orionis. [Kraus et al. 2017]Trapped in a Vortex?ALMAs observations of V1247 Orionis are reported by a team of scientists led by Stefan

  14. Cosmological simulation with dust formation and destruction

    Science.gov (United States)

    Aoyama, Shohei; Hou, Kuan-Chou; Hirashita, Hiroyuki; Nagamine, Kentaro; Shimizu, Ikkoh

    2018-06-01

    To investigate the evolution of dust in a cosmological volume, we perform hydrodynamic simulations, in which the enrichment of metals and dust is treated self-consistently with star formation and stellar feedback. We consider dust evolution driven by dust production in stellar ejecta, dust destruction by sputtering, grain growth by accretion and coagulation, and grain disruption by shattering, and treat small and large grains separately to trace the grain size distribution. After confirming that our model nicely reproduces the observed relation between dust-to-gas ratio and metallicity for nearby galaxies, we concentrate on the dust abundance over the cosmological volume in this paper. The comoving dust mass density has a peak at redshift z ˜ 1-2, coincident with the observationally suggested dustiest epoch in the Universe. In the local Universe, roughly 10 per cent of the dust is contained in the intergalactic medium (IGM), where only 1/3-1/4 of the dust survives against dust destruction by sputtering. We also show that the dust mass function is roughly reproduced at ≲ 108 M⊙, while the massive end still has a discrepancy, which indicates the necessity of stronger feedback in massive galaxies. In addition, our model broadly reproduces the observed radial profile of dust surface density in the circum-galactic medium (CGM). While our model satisfies the observational constraints for the dust extinction on cosmological scales, it predicts that the dust in the CGM and IGM is dominated by large (>0.03 μm) grains, which is in tension with the steep reddening curves observed in the CGM.

  15. Respiratory Toxicity of Lunar Highland Dust

    Science.gov (United States)

    James, John T.; Lam, Chiu-wing; Wallace, William T.

    2009-01-01

    Lunar dust exposures occurred during the Apollo missions while the crew was on the lunar surface and especially when microgravity conditions were attained during rendezvous in lunar orbit. Crews reported that the dust was irritating to the eyes and in some cases respiratory symptoms were elicited. NASA s vision for lunar exploration includes stays of 6 months on the lunar surface hence the health effects of periodic exposure to lunar dust need to be assessed. NASA has performed this assessment with a series of in vitro and in vivo tests on authentic lunar dust. Our approach is to "calibrate" the intrinsic toxicity of lunar dust by comparison to a nontoxic dust (TiO2) and a highly toxic dust (quartz) using intratrachael instillation of the dusts in mice. A battery of indices of toxicity is assessed at various time points after the instillations. Cultures of selected cells are exposed to test dusts to assess the adverse effects on the cells. Finally, chemical systems are used to assess the nature of the reactivity of various dusts and to determine the persistence of reactivity under various environmental conditions that are relevant to a space habitat. Similar systems are used to assess the dissolution of the dust. From these studies we will be able to set a defensible inhalation exposure standard for aged dust and predict whether we need a separate standard for reactive dust. Presently-available data suggest that aged lunar highland dust is slightly toxic, that it can adversely affect cultured cells, and that the surface reactivity induced by grinding the dust persists for a few hours after activation.

  16. Design and development of a dust dispersion chamber to quantify the dispersibility of rock dust.

    Science.gov (United States)

    Perera, Inoka E; Sapko, Michael J; Harris, Marcia L; Zlochower, Isaac A; Weiss, Eric S

    2016-01-01

    Dispersible rock dust must be applied to the surfaces of entries in underground coal mines in order to inert the coal dust entrained or made airborne during an explosion and prevent propagating explosions. 30 CFR. 75.2 states that "… [rock dust particles] when wetted and dried will not cohere to form a cake which will not be dispersed into separate particles by a light blast of air …" However, a proper definition or quantification of "light blast of air" is not provided. The National Institute for Occupational Safety and Health (NIOSH) has, consequently, designed a dust dispersion chamber to conduct quantitative laboratory-scale dispersibility experiments as a screening tool for candidate rock dusts. A reproducible pulse of air is injected into the chamber and across a shallow tray of rock dust. The dust dispersed and carried downwind is monitored. The mass loss of the dust tray and the airborne dust measurements determine the relative dispersibility of the dust with respect to a Reference rock dust. This report describes the design and the methodology to evaluate the relative dispersibility of rock dusts with and without anti-caking agents. Further, the results of this study indicate that the dispersibility of rock dusts varies with particle size, type of anti-caking agent used, and with the untapped bulk density. Untreated rock dusts, when wetted and dried forming a cake that was much less dispersible than the reference rock dust used in supporting the 80% total incombustible content rule.

  17. Step by step in dust control

    Energy Technology Data Exchange (ETDEWEB)

    Archer, N. [Arch Environmental Equipment, Inc. (United States)

    2003-05-01

    The paper examines the different stages in identifying delegating and controlling dust before it becomes a serious problem for a facility. Material handling, processing, storage and traffic are the major dust producing sources. All industries that convey dry, light material need to install a dust control system. The confine-seal-suppress method of dust control has provided excellent results in numerous applications, only with the combination of all three will maximum dust control. When a system is properly engineered and correctly installed, meeting the EPA Government standards becomes very easy, and is necessary in to the operation of a quality facility. 5 photos.

  18. Dust bands in the asteroid belt

    International Nuclear Information System (INIS)

    Sykes, M.V.; Greenberg, R.; Dermott, S.F.; Nicholson, P.D.; Burns, J.A.

    1989-01-01

    This paper describes the original IRAS observations leading to the discovery of the three dust bands in the asteroid belt and the analysis of data. Special attention is given to an analytical model of the dust band torus and to theories concerning the origin of the dust bands, with special attention given to the collisional equilibrium (asteroid family), the nonequilibrium (random collision), and the comet hypotheses of dust-band origin. It is noted that neither the equilibrium nor nonequilibrium models, as currently formulated, present a complete picture of the IRAS dust-band observations. 32 refs

  19. Linear Alkylbenzenesulfonates in indoor Floor Dust

    DEFF Research Database (Denmark)

    Madsen, Jørgen Øgaard; Wolkoff, Peder; Madsen, Jørgen Øgaard

    1999-01-01

    The amount of Linear Alkylbenzenesulfonates (LAS) in the particle fraction of floor dust sampled from 7 selected public buildings varied between 34 and 1500 microgram per gram dust, while the contents of the fibre fractions generally were higher with up to 3500 microgram LAS/g dust. The use...... of a cleaning agent with LAS resulted in an increase of the amount of LAS in the floor dust after floor wash relative to just before floor wash. However, the most important source of LAS in the indoor floor dust appears to be residues of detergent in clothing. Thus, a newly washed shirt contained 2960 microgram...

  20. Time-Dependent Dust Formation in Novae

    Directory of Open Access Journals (Sweden)

    Kyung-Won Suh

    1991-06-01

    Full Text Available The dust formation processes in novae are investigated with close attention to recent infrared observations. Using mainly the classical nucleation theory, we have calculated the time scales of dust formation and growth in the environments of novae. Those time scales roughly resemble the typical observations. We have classified the dust-forming novae into three classes according to their explosion properties and the thermodynamic properties of dust grains. Oxygen grains from much later than carbon grains because of their thermodynamic properties. The effect of grain formation to the efficiency of stellar winds to drive the material outward is tested with newly obtained Planck mean values of dust grains.

  1. Numerical Prediction of Dust. Chapter 10

    Science.gov (United States)

    Benedetti, Angela; Baldasano, J. M.; Basart, S.; Benincasa, F.; Boucher, O.; Brooks, M.; Chen, J. P.; Colarco, P. R.; Gong, S.; Huneeus, N.; hide

    2013-01-01

    Covers the whole breadth of mineral dust research, from a scientific perspective Presents interdisciplinary work including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies Explores the role of dust as a player and recorder of environmental change This volume presents state-of-the-art research about mineral dust, including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies. Dust research is a new, dynamic and fast-growing area of science and due to its multiple roles in the Earth system, dust has become a fascinating topic for many scientific disciplines. Aspects of dust research covered in this book reach from timescales of minutes (as with dust devils, cloud processes, and radiation) to millennia (as with loess formation and oceanic sediments), making dust both a player and recorder of environmental change. The book is structured in four main parts that explore characteristics of dust, the global dust cycle, impacts of dust on the Earth system, and dust as a climate indicator. The chapters in these parts provide a comprehensive, detailed overview of this highly interdisciplinary subject. The contributions presented here cover dust from source to sink and describe all the processes dust particles undergo while travelling through the atmosphere. Chapters explore how dust is lifted and transported, how it affects radiation, clouds, regional circulations, precipitation and chemical processes in the atmosphere, and how it deteriorates air quality. The book explores how dust is removed from the atmosphere by gravitational settling, turbulence or precipitation, how iron contained in dust fertilizes terrestrial and marine ecosystems, and about the role that dust plays in human health. We learn how dust is observed, simulated using computer models and forecast. The book also details the role of dust deposits for climate reconstructions

  2. Dust removal system for fusion experimental reactors

    International Nuclear Information System (INIS)

    Onozuka, M.; Ueda, Y.; Takahashi, K.; Oda, Y.; Seki, Y.; Ueda, S.; Aoki, I.

    1995-01-01

    Development of a dust removal system using static electricity has been conducted. It is envisioned that the system can collect and transport dust under vacuum. In the system, the dust is charged by dielectric polarization and floated by an electrostatic attraction force that is generated by the DC electric field. The dust is then transported by the electric curtain formed by the three-phase AC electric field. Experimental investigation has been conducted to examine the characteristics of the system. Current research results indicate that the dust removal system using static electricity can be used for fusion experimental reactors

  3. Dust removal system for fusion experimental reactors

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, M.; Ueda, Y.; Takahashi, K.; Oda, Y. [Mitsubishi Heavy Industries, Ltd., Yokohama (Japan); Seki, Y.; Ueda, S.; Aoki, I. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)

    1995-12-31

    Development of a dust removal system using static electricity has been conducted. It is envisioned that the system can collect and transport dust under vacuum. In the system, the dust is charged by dielectric polarization and floated by an electrostatic attraction force that is generated by the DC electric field. The dust is then transported by the electric curtain formed by the three-phase AC electric field. Experimental investigation has been conducted to examine the characteristics of the system. Current research results indicate that the dust removal system using static electricity can be used for fusion experimental reactors.

  4. Fast monitoring of indoor bioaerosol concentrations with ATP bioluminescence assay using an electrostatic rod-type sampler.

    Directory of Open Access Journals (Sweden)

    Ji-Woon Park

    Full Text Available A culture-based colony counting method is the most widely used analytical technique for monitoring bioaerosols in both indoor and outdoor environments. However, this method requires several days for colony formation. In this study, our goal was fast monitoring (Sampling: 3 min, Detection: < 1 min of indoor bioaerosol concentrations with ATP bioluminescence assay using a bioaerosol sampler. For this purpose, a novel hand-held electrostatic rod-type sampler (110 mm wide, 115 mm long, and 200 mm tall was developed and used with a commercial luminometer, which employs the Adenosine triphosphate (ATP bioluminescence method. The sampler consisted of a wire-rod type charger and a cylindrical collector, and was operated with an applied voltage of 4.5 kV and a sampling flow rate of 150.7 lpm. Its performance was tested using Staphylococcus epidermidis which was aerosolized with an atomizer. Bioaerosol concentrations were measured using ATP bioluminescence method with our sampler and compared with the culture-based method using Andersen cascade impactor under controlled laboratory conditions. Indoor bioaerosol concentrations were also measured using both methods in various indoor environments. A linear correlation was obtained between both methods in lab-tests and field-tests. Our proposed sampler with ATP bioluminescence method may be effective for fast monitoring of indoor bioaerosol concentrations.

  5. Comparison of particulate matter exposure estimates in young children from personal sampling equipment and a robotic sampler.

    Science.gov (United States)

    Sagona, Jessica A; Shalat, Stuart L; Wang, Zuocheng; Ramagopal, Maya; Black, Kathleen; Hernandez, Marta; Mainelis, Gediminas

    2017-05-01

    Accurate characterization of particulate matter (PM) exposure in young children is difficult, because personal samplers are often too heavy, bulky or impractical to be used. The Pretoddler Inhalable Particulate Environmental Robotic (PIPER) sampler was developed to help address this problem. In this study, we measured inhalable PM exposures in 2-year-olds via a lightweight personal sampler worn in a small backpack and evaluated the use of a robotic sampler with an identical sampling train for estimating PM exposure in this age group. PM mass concentrations measured by the personal sampler ranged from 100 to almost 1,200 μg/m 3 , with a median value of 331 μg/m 3 . PM concentrations measured by PIPER were considerably lower, ranging from 14 to 513 μg/m 3 with a median value of 56 μg/m 3 . Floor cleaning habits and activity patterns of the 2-year-olds varied widely by home; vigorous play and recent floor cleaning were most associated with higher personal exposure. Our findings highlight the need for additional characterization of children's activity patterns and their effect on personal exposures.

  6. Comparison of POCIS passive samplers vs. composite water sampling: A case study.

    Science.gov (United States)

    Criquet, Justine; Dumoulin, David; Howsam, Michael; Mondamert, Leslie; Goossens, Jean-François; Prygiel, Jean; Billon, Gabriel

    2017-12-31

    The relevance of Polar Organic Chemical Integrative Samplers (POCIS) was evaluated for the assessment of concentrations of 46 pesticides and 19 pharmaceuticals in a small, peri-urban river with multi-origin inputs. Throughout the period of POCIS deployment, 24h-average water samples were collected automatically, and showed the rapid temporal evolution of concentrations of several micropollutants, as well as permitting the calculation of average concentrations in the water phase for comparison with those estimated from POCIS passive samplers. In the daily water samples, cyproconazol, epoxyconazol and imidacloprid showed high temporal variations with concentrations ranging from under the limit of detection up to several hundreds of ngL -1 . Erythromycin, cyprofloxacin and iopromide also increased rapidly up to tens of ngL -1 within a few days. Conversely, atrazine, caffeine, diclofenac, and to a lesser extent carbamazepine and sucralose, were systematically present in the water samples and showed limited variation in concentrations. For most of the substances studied here, the passive samplers gave reliable average concentrations between the minimal and maximal daily concentrations during the time of deployment. For pesticides, a relatively good correlation was clearly established (R 2 =0.89) between the concentrations obtained by POCIS and those gained from average water samples. A slight underestimation of the concentration by POCIS can be attributed to inappropriate sampling rates extracted from the literature and for our system, and new values are proposed. Considering the all data set, 75% of the results indicate a relatively good agreement between the POCIS and the average water samples concentration (values of the ratio ranging between 0,33 and 3). Note further that this agreement between these concentrations remains valid considering different sampling rates extracted from the literature. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Observations on persistent organic pollutants in indoor and outdoor air using passive polyurethane foam samplers

    Science.gov (United States)

    Bohlin, Pernilla; Jones, Kevin C.; Tovalin, Horacio; Strandberg, Bo

    Air quality data of persistent organic pollutants (POPs) indoors and outdoors are sparse or lacking in several parts of the world, often hampered by the cost and inconvenience of active sampling techniques. Cheap and easy passive air sampling techniques are therefore helpful for reconnaissance surveys. As a part of the Megacity Initiative: Local and Global Research Observations (MILAGRO) project in Mexico City Metropolitan Area in 2006, a range of POPs (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs)) were analyzed in polyurethane foam (PUF) disks used as passive samplers in indoor and outdoor air. Results were compared to those from samplers deployed simultaneously in Gothenburg (Sweden) and Lancaster (United Kingdom). Using sampling rates suggested in the literature, the sums of 13 PAHs in the different sites were estimated to be 6.1-180 ng m -3, with phenanthrene as the predominant compound. Indoor PAH levels tended to be higher in Gothenburg and outdoor levels higher in Mexico City. The sum of PCBs ranged 59-2100 ng m -3, and seemed to be highest indoors in Gothenburg and Lancaster. PBDE levels (sum of seven) ranged 0.68-620 ng m -3, with the highest levels found in some indoor locations. OCPs (i.e. DDTs, HCHs, and chlordanes) were widely dispersed both outdoors and indoors at all three studied areas. In Gothenburg all POPs tended to be higher indoors than outdoors, while indoor and outdoor levels in Mexico City were similar. This could be due to the influence of indoor and outdoor sources, air exchange rates, and lifestyle factors. The study demonstrates how passive samplers can provide quick and cheap reconnaissance data simultaneously at many locations which can shed light on sources and other factors influencing POP levels in air, especially for the gaseous fractions.

  8. astroABC : An Approximate Bayesian Computation Sequential Monte Carlo sampler for cosmological parameter estimation

    Energy Technology Data Exchange (ETDEWEB)

    Jennings, E.; Madigan, M.

    2017-04-01

    Given the complexity of modern cosmological parameter inference where we arefaced with non-Gaussian data and noise, correlated systematics and multi-probecorrelated data sets, the Approximate Bayesian Computation (ABC) method is apromising alternative to traditional Markov Chain Monte Carlo approaches in thecase where the Likelihood is intractable or unknown. The ABC method is called"Likelihood free" as it avoids explicit evaluation of the Likelihood by using aforward model simulation of the data which can include systematics. Weintroduce astroABC, an open source ABC Sequential Monte Carlo (SMC) sampler forparameter estimation. A key challenge in astrophysics is the efficient use oflarge multi-probe datasets to constrain high dimensional, possibly correlatedparameter spaces. With this in mind astroABC allows for massive parallelizationusing MPI, a framework that handles spawning of jobs across multiple nodes. Akey new feature of astroABC is the ability to create MPI groups with differentcommunicators, one for the sampler and several others for the forward modelsimulation, which speeds up sampling time considerably. For smaller jobs thePython multiprocessing option is also available. Other key features include: aSequential Monte Carlo sampler, a method for iteratively adapting tolerancelevels, local covariance estimate using scikit-learn's KDTree, modules forspecifying optimal covariance matrix for a component-wise or multivariatenormal perturbation kernel, output and restart files are backed up everyiteration, user defined metric and simulation methods, a module for specifyingheterogeneous parameter priors including non-standard prior PDFs, a module forspecifying a constant, linear, log or exponential tolerance level,well-documented examples and sample scripts. This code is hosted online athttps://github.com/EliseJ/astroABC

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

    Science.gov (United States)

    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.

  10. Inter-annual changes of Biomass Burning and Desert Dust and their impact over East Asia

    Science.gov (United States)

    DONG, X.; Fu, J. S.; Huang, K.

    2014-12-01

    Impact of mineral dust and biomass burning aerosols on air quality has been well documented in the last few decades, but the knowledge about their interactions with anthropogenic emission and their impacts on regional climate is very limited (IPCC, 2007). While East Asia is greatly affected by dust storms in spring from Taklamakan and Gobi deserts (Huang et al., 2010; Li et al., 2012), it also suffers from significant biomass burning emission from Southeast Asia during the same season. Observations from both surface monitoring and satellite data indicated that mineral dust and biomass burning aerosols may approach to coastal area of East Asia simultaneously, thus have a very unique impact on the local atmospheric environment and regional climate. In this study, we first investigated the inter-annual variations of biomass burning and dust aerosols emission for 5 consecutive years from 2006-2010 to estimate the upper and lower limits and correlation with meteorology conditions, and then evaluate their impacts with a chemical transport system. Our preliminary results indicated that biomass burning has a strong correlation with precipitation over Southeast Asia, which could drive the emission varying from 542 Tg in 2008 to 945 Tg in 2010, according to FLAMBE emission inventory (Reid et al., 2009). Mineral dust also demonstrated a strong dependence on wind filed. These inter-annual/annual variations will also lead to different findings and impacts on air quality in East Asia. Reference: Huang, K., et al. (2010), Mixing of Asian dust with pollution aerosol and the transformation of aerosol components during the dust storm over China in spring 2007, Journal of Geophysical Research-Atmospheres, 115. IPCC (2007), Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, New York. Li, J., et al. (2012), Mixing of Asian mineral dust with anthropogenic pollutants over East Asia: a model case study of a super-duststorm in

  11. Field test of the PNNL Automated Radioxenon Sampler/Analyzer (ARSA)

    International Nuclear Information System (INIS)

    Lagomarsino, R.J.; Ku, E.; Latner, N.; Sanderson, C.G.

    1998-07-01

    As part of the requirements of the Comprehensive Test Ban Treaty (CTBT), the Automated Radioxenon/Sampler Analyzer (ARSA) was designed and engineered by the Pacific Northwest National Laboratory (PNNL). The instrument is to provide near real-time detection and measurement of the radioxenons released into the atmosphere after a nuclear test. Forty-six field tests, designed to determine the performance of the ARSA prototype under simulated field conditions, were conducted at EML from March to December 1997. This final report contains detailed results of the tests with recommendations for improvements in instrument performance

  12. Field test of the PNNL Automated Radioxenon Sampler/Analyzer (ARSA)

    Energy Technology Data Exchange (ETDEWEB)

    Lagomarsino, R.J.; Ku, E.; Latner, N.; Sanderson, C.G.

    1998-07-01

    As part of the requirements of the Comprehensive Test Ban Treaty (CTBT), the Automated Radioxenon/Sampler Analyzer (ARSA) was designed and engineered by the Pacific Northwest National Laboratory (PNNL). The instrument is to provide near real-time detection and measurement of the radioxenons released into the atmosphere after a nuclear test. Forty-six field tests, designed to determine the performance of the ARSA prototype under simulated field conditions, were conducted at EML from March to December 1997. This final report contains detailed results of the tests with recommendations for improvements in instrument performance.

  13. A Hybrid MCMC Sampler for Unconditional Quantile Based on Influence Function

    Directory of Open Access Journals (Sweden)

    El Moctar Laghlal

    2018-05-01

    Full Text Available In this study, we provide a Bayesian estimation method for the unconditional quantile regression model based on the Re-centered Influence Function (RIF. The method makes use of the dichotomous structure of the RIF and estimates a non-linear probability model by a logistic regression using a Gibbs within a Metropolis-Hastings sampler. This approach performs better in the presence of heavy-tailed distributions. Applied to a nationally-representative household survey, the Senegal Poverty Monitoring Report (2005, the results show that the change in the rate of returns to education across quantiles is substantially lower at the primary level.

  14. Diurnal measurement of equilibrium equivalent radon/thoron concentration using time integrated flow mode grab sampler

    International Nuclear Information System (INIS)

    Pant, P.; Kandari, T.; Ramola, R.C.; Semwal, C.P.; Prasad, M.

    2018-01-01

    The basic processes which influenced the concentration of radon and thoron decay products are- attachment, recoil and deposition and by the room specific parameters of radon exhalation and ventilation. The freshly formed decay products have a high diffusivities (especially in air) and ability to stick to surfaces. According to UNSCEAR 1977, radon daughters may be combined as the so called equilibrium equivalent concentration which is related to the potential alpha energy distribution concentration. In the present study an effort has been made to see the diurnal variation of radon and thoron progeny concentration using time integrated flow mode sampler

  15. ORIGIN OF DUST AROUND V1309 SCO

    International Nuclear Information System (INIS)

    Zhu, Chunhua; Lü, Guoliang; Wang, Zhaojun

    2013-01-01

    The origin of dust grains in the interstellar medium is still an unanswered problem. Nicholls et al. found the presence of a significant amount of dust around V1309 Sco, which may originate from the merger of a contact binary. We investigate the origin of dust around V1309 Sco and suggest that these dust grains are produced in the binary-merger ejecta. By means of the AGBDUST code, we estimate that ∼5.2 × 10 –4 M ☉ dust grains are produced with a radii of ∼10 –5 cm. These dust grains are mainly composed of silicate and iron grains. Because the mass of the binary merger ejecta is very small, the contribution of dust produced by binary merger ejecta to the overall dust production in the interstellar medium is negligible. However, it is important to note that the discovery of a significant amount of dust around V1309 Sco offers a direct support for the idea that common-envelope ejecta provides an ideal environment for dust formation and growth. Therefore, we confirm that common envelope ejecta can be important source of cosmic dust

  16. Engineering-scale dust control experiments

    International Nuclear Information System (INIS)

    Winberg, M.R.; Pawelko, R.J.; Jacobs, N.C.; Thompson, D.N.

    1990-12-01

    This report presents the results of engineering scale dust-control experiments relating to contamination control during handling of transuranic waste. These experiments focused on controlling dust during retrieval operations of buried waste where waste and soil are intimately mixed. Sources of dust generation during retrieval operations include digging, dumping, and vehicle traffic. Because contaminants are expected to attach to soil particles and move with the generated dust, control of the dust spread may be the key to contamination control. Dust control techniques examined in these experiments include the use of misting systems, soil fixatives, and dust suppression agents. The Dryfog Ultrasonic Misting Head, manufactured by Sonics, Incorporated, and ENTAC, an organic resin derived from tree sap manufactured by ENTAC Corporation, were tested. The results of the experiments include product performance and recommended application methods. 19 figs., 7 refs., 6 tabs

  17. COSMIC DUST AGGREGATION WITH STOCHASTIC CHARGING

    International Nuclear Information System (INIS)

    Matthews, Lorin S.; Hyde, Truell W.; Shotorban, Babak

    2013-01-01

    The coagulation of cosmic dust grains is a fundamental process which takes place in astrophysical environments, such as presolar nebulae and circumstellar and protoplanetary disks. Cosmic dust grains can become charged through interaction with their plasma environment or other processes, and the resultant electrostatic force between dust grains can strongly affect their coagulation rate. Since ions and electrons are collected on the surface of the dust grain at random time intervals, the electrical charge of a dust grain experiences stochastic fluctuations. In this study, a set of stochastic differential equations is developed to model these fluctuations over the surface of an irregularly shaped aggregate. Then, employing the data produced, the influence of the charge fluctuations on the coagulation process and the physical characteristics of the aggregates formed is examined. It is shown that dust with small charges (due to the small size of the dust grains or a tenuous plasma environment) is affected most strongly

  18. Efficacy and safety of sublingual tablets of house dust mite allergen extracts in adults with allergic rhinitis

    NARCIS (Netherlands)

    Bergmann, Karl-Christian; Demoly, Pascal; Worm, Margitta; Fokkens, Wytske J.; Carrillo, Teresa; Tabar, Ana I.; Nguyen, Hélène; Montagut, Armelle; Zeldin, Robert K.

    2014-01-01

    Preliminary studies have suggested the efficacy of sublingual tablets of house dust mite (HDM) extracts in adults with allergic rhinitis. We sought to assess the efficacy and safety of 2 doses of HDM sublingual tablets over 1 treatment year and the subsequent immunotherapy-free year. Adults with

  19. Exposure to inhalable dust, wheat flour and alpha-amylase allergens in industrial and traditional bakeries.

    Science.gov (United States)

    Bulat, Petar; Myny, Katrien; Braeckman, Lutgart; van Sprundel, Marc; Kusters, Edouard; Doekes, Gert; Pössel, Kerstin; Droste, Jos; Vanhoorne, Michel

    2004-01-01

    This study was designed to characterize exposure to inhalable dust, wheat flour and alpha-amylase allergens in industrial and traditional bakeries. The study included 70 bakeries from the northern part of Belgium. Based on the degree of automation and a clear division of individual job tasks, four bakeries were identified as industrial and the remaining 66 were identified as traditional ones. Personal, as well as stationary, samples of inhalable dust were collected during full shift periods, usually 5-7 h. The portable pumps aspirated 2 l/min through Teflon personal dust samplers (Millipore, pore size 1.0 microm) mounted in PAS-6 sampling heads. In the collected samples the inhalable dust, wheat flour and alpha-amylase allergens were determined. Wheat flour allergens were measured using enzyme-linked immunosorbent assay inhibition and an antiwheat IgG4 serum pool. The alpha-amylase allergens were measured using a sandwich enzyme immunoassay with affinity-purified polyclonal rabbit IgG antibodies. In total, 440 samples (300 personal and 140 stationary) were processed. The highest inhalable dust exposure was observed in traditional bakeries among bread [geometric mean (GM) 2.10 mg/m3] and bread and pastry workers (GM 1.80 mg/m3). In industrial bakeries the highest dust exposure was measured in bread-producing workers (GM 1.06 mg/m3). Similar relations were observed for wheat flour and alpha-amylase allergens. Bread baking workers in traditional bakeries had the highest exposure to both allergens (wheat flour GM 22.33 microg/m(3), alpha-amylase GM 0.61 ng/m3). The exposure to wheat flour and alpha-amylase allergens in industrial bakeries was higher in bread baking workers (wheat flour GM 6.15 microg/m3, alpha-amylase GM 0.47 ng/m3) than in bread packing workers (wheat flour GM 2.79 microg/m3, alpha-amylase GM 0.15 ng/m3). The data presented suggest that, on average, exposure in the Belgium bakeries studied-industrial as well as traditional-is lower than or similar to

  20. Assessment of dust exposure in a steel plant in the eastern coast of peninsular Malaysia.

    Science.gov (United States)

    Nurul, Ainun Hamzah; Shamsul, Bahri Mohd Tamrin; Noor Hassim, Ismail

    2016-11-22

    Steel manufacturing produces dust, fumes, and pollutant gases that may give adverse health effects to the respiratory function of workers. Improper occupational hygiene practice in the workplace will affect both workers wellbeing and productivity. To assess the level of particulate matter [(PM2.5, PM10, and Total Particulate Matter (TPM)], and trace metal dust concentrations in different sections of a steel plant and compare with the occupational exposure values. The work environmental parameters of the particulate matters were evaluated using Indoor Air Quality, while metal dust concentrations were measured using portable personal air sampler. A total of 184 personal samples were randomly collected from workers in three major sections; steel making plant, direct reduced plant, and support group. Trace metal dust concentrations were subjected to wet mineral acid mixture digestion and analysed by atomic absorption spectrophotometer (AAS). The overall average PM2.5 concentration observed was varied according to the section: steel making plant was 0.18 mg/m3, direct reduced iron plant was 0.05 mg/m3, and support plant was 0.05 mg/m3. Average PM 10 concentration in steel making shop (SMS) plant, direct reduced (DR) plant, and support plant were 0.70 mg/m3, 0.84 mg/m3, and 0.58 mg/m3, respectively. The average TWA8 of trace metal dusts (cobalt and chromium) in all the sections exceeded 1 to 3 times the ACGIH prescribed values, OSHA PELs, NIOSH RELs as well as USECHH OSHA, whereas TWA8 concentration of nickel for each section did not exceed the occupational exposure values. The average PM2.5, PM10 and TPM did not exceed the prescribed values, while average trace metal dust concentration TWA8 for cobalt and chromium in all plants exceeded occupational exposure prescribed values. However, the nickel found did not exceed the prescribed values in all the plants except for NIOSH RELs.

  1. Coupling Mars' Dust and Water Cycles: Effects on Dust Lifting Vigor, Spatial Extent and Seasonality

    Science.gov (United States)

    Kahre, M. A.; Hollingsworth, J. L.; Haberle, R. M.; Montmessin, F.

    2012-01-01

    The dust cycle is an important component of Mars' current climate system. Airborne dust affects the radiative balance of the atmosphere, thus greatly influencing the thermal and dynamical state of the atmosphere. Dust raising events on Mars occur at spatial scales ranging from meters to planet-wide. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. Generally, a low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading were observed by MGS/TES: one peak occurred before northern winter solstice at Ls 200-240, and one peak occurred after northern winter solstice at L(sub s) 305-340. These maxima in dust loading are thought to be associated with transient eddy activity in the northern hemisphere, which has been observed to maximize pre- and post-solstice. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading. Interactive dust cycle studies typically have not included the formation of water ice clouds or their radiative effects. Water ice clouds can influence the dust cycle by scavenging dust from atmosphere and by interacting with solar and infrared radiation

  2. Effects of studded tires on roadside airborne dust pollution in Niigata, Japan

    Science.gov (United States)

    Fukuzaki, Norio; Yanaka, Takaaki; Urushiyama, Yoshio

    Two series of dust samples, collected by Andersen impactors (denoted by AN) and low-volume air samplers (denoted by LV), were investigated with respect to roadside airborne dusts collected in two different periods in 1983. These were the periods (i) with studded tires (February and March) and (ii) without studded tires (October). Multi-element determinations of these samples were made by neutron activation analysis and atomic absorption spectrometry. The total concentration of AN in roadside air for period (i) was about three times higher than for the period without studded tires. The lithophilic elements such as Na, Al, K, Ca, Ti, Fe and Th, and component-metal elements of stud tip, W and Ta, produced a significant increase in atmospheric concentration in winter. The contribution of pavement material, one of the most interesting components of airborne particles in this study, was related to total AN and LV by the chemical element balance method. It made up only 16 percent (9.1 μgm -3) of AN in October, compared with 46 percent (70.2 μgm -3) in February. It was also observed that the atmospheric concentrations of pavement debris to total LV decreased with the distance from the road to each sampling site.

  3. Tidal sampler

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1978-01-01

    An apparatus is described for pumping a sample of water or other liquid that uses the energy generated from the rise and fall of the liquid level to force a sample of the liquid into a collection vessel. A suction vessel and booster vessel with interconnecting tubing and check valves are responsive to an oscillating liquid level to pump a portion of said liquid into a collection vessel

  4. House Dust Mite Respiratory Allergy

    DEFF Research Database (Denmark)

    Calderón, Moisés A; Kleine-Tebbe, Jörg; Linneberg, Allan

    2015-01-01

    Although house dust mite (HDM) allergy is a major cause of respiratory allergic disease, specific diagnosis and effective treatment both present unresolved challenges. Guidelines for the treatment of allergic rhinitis and asthma are well supported in the literature, but specific evidence on the e......Although house dust mite (HDM) allergy is a major cause of respiratory allergic disease, specific diagnosis and effective treatment both present unresolved challenges. Guidelines for the treatment of allergic rhinitis and asthma are well supported in the literature, but specific evidence...... not extend beyond the end of treatment. Finally, allergen immunotherapy has a poor but improving evidence base (notably on sublingual tablets) and its benefits last after treatment ends. This review identifies needs for deeper physician knowledge on the extent and impact of HDM allergy in respiratory disease...... and therapy of HDM respiratory allergy in practice....

  5. Development of a silicone-membrane passive sampler for monitoring cylindrospermopsin and microcystin LR-YR-RR in natural waters

    Science.gov (United States)

    Nyoni, Hlengilizwe; Mamba, Bhekie B.; Msagati, Titus A. M.

    2017-08-01

    Silicone membrane tubes were functionalised by filling them with synthesised γ-Fe2O3 nanoparticles and used as a passive sampling device for monitoring microcystins and cylindrospermopsin in aquatic environments. This novel device was calibrated for the measurement of microcystin and cylindrospermopsin concentrations in water. The effect of temperature and hydrodynamics on the sampler performance was studied in a flow-through system under controlled conditions. The chemical uptake of microcystins (MCs) and cylindrospermopsin (CYN) into the passive sampler remained linear and integrative throughout the exposure period. The rate of accumulation of most of the MC compounds tested was dependent on temperature and flow velocity. The use of 13C labelled polychlorinated biphenyls as performance reference compounds (PRCs) in silicone membrane/γ-Fe2O3 nanoparticle passive sampler, Chemcatcher and polar organic chemical integrative sampler (POCIS) was evaluated. The majority of PRCs improved the semi quantitative nature of water concentration estimated by the three samplers. The corrected sampling rate values of model biotoxin compounds were used to estimate the time-weighted average concentrations in natural cyanobacterial water blooms of the Hartbeespoort dam. The corrected sampling rates RScorr values varied from 0.1140 to 0.5628 Ld-1 between samplers with silicone membrane having the least RScorr values compared to the Chemcatcher and POCIS. The three passive sampling devises provided a more relevant picture of the biotoxin concentration in the Hartbeespoort dam. The results suggested that the three sampling devices are suitable for use in monitoring microcystins and cylindrospermopsin concentrations in aquatic environments.

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

    Science.gov (United States)

    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.

  7. Calibration and use of the polar organic chemical integrative sampler--a critical review.

    Science.gov (United States)

    Harman, Christopher; Allan, Ian John; Vermeirssen, Etiënne L M

    2012-12-01

    The implementation of strict environmental quality standards for polar organic priority pollutants poses a challenge for monitoring programs. The polar organic chemical integrative sampler (POCIS) may help to address the challenge of measuring low and fluctuating trace concentrations of such organic contaminants, offering significant advantages over traditional sampling. In the present review, the authors evaluate POCIS calibration methods and factors affecting sampling rates together with reported environmental applications. Over 300 compounds have been shown to accumulate in POCIS, including pesticides, pharmaceuticals, hormones, and industrial chemicals. Polar organic chemical integrative sampler extracts have been used for both chemical and biological analyses. Several different calibration methods have been described, which makes it difficult to directly compare sampling rates. In addition, despite the fact that some attempts to correlate sampling rates with the properties of target compounds such as log K(OW) have been met with varying success, an overall model that can predict uptake is lacking. Furthermore, temperature, water flow rates, salinity, pH, and fouling have all been shown to affect uptake; however, there is currently no robust method available for adjusting for these differences. Overall, POCIS has been applied to a wide range of sampling environments and scenarios and has been proven to be a useful screening tool. However, based on the existing literature, a more mechanistic approach is required to increase understanding and thus improve the quantitative nature of the measurements. Copyright © 2012 SETAC.

  8. Silicone Wristband Passive Samplers Yield Highly Individualized Pesticide Residue Exposure Profiles.

    Science.gov (United States)

    Aerts, Raf; Joly, Laure; Szternfeld, Philippe; Tsilikas, Khariklia; De Cremer, Koen; Castelain, Philippe; Aerts, Jean-Marie; Van Orshoven, Jos; Somers, Ben; Hendrickx, Marijke; Andjelkovic, Mirjana; Van Nieuwenhuyse, An

    2018-01-02

    Monitoring human exposure to pesticides and pesticide residues (PRs) remains crucial for informing public health policies, despite strict regulation of plant protection product and biocide use. We used 72 low-cost silicone wristbands as noninvasive passive samplers to assess cumulative 5-day exposure of 30 individuals to polar PRs. Ethyl acetate extraction and LC-MS/MS analysis were used for the identification of PRs. Thirty-one PRs were detected of which 15 PRs (48%) were detected only in worn wristbands, not in environmental controls. The PRs included 16 fungicides (52%), 8 insecticides (26%), 2 herbicides (6%), 3 pesticide derivatives (10%), 1 insect repellent (3%), and 1 pesticide synergist (3%). Five detected pesticides were not approved for plant protection use in the EU. Smoking and dietary habits that favor vegetable consumption were associated with higher numbers and higher cumulative concentrations of PRs in wristbands. Wristbands featured unique PR combinations. Our results suggest both environment and diet contributed to PR exposure in our study group. Silicone wristbands could serve as sensitive passive samplers to screen population-wide cumulative dietary and environmental exposure to authorized, unauthorized and banned pesticides.

  9. A rapidly equilibrating, thin film, passive water sampler for organic contaminants; characterization and field testing

    Energy Technology Data Exchange (ETDEWEB)

    St George, Tiffany [Department of Marine Science, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340 (United States); Department of Science, United States Coast Guard Academy, 27 Mohegan Ave., New London, CT 06320 (United States); Vlahos, Penny, E-mail: penny.vlahos@uconn.ed [Department of Chemistry, University of Connecticut, 55 Eagleville Road, Storrs, CT 06269 (United States); Department of Marine Science, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340 (United States); Harner, Tom [Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4 (Canada); Helm, Paul [Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, 125 Resources Rd, Toronto, Ontario M9P 3V6 (Canada); Wilford, Bryony [Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4 (Canada)

    2011-02-15

    Improving methods for assessing the spatial and temporal resolution of organic compound concentrations in marine environments is important to the sustainable management of our coastal systems. Here we evaluate the use of ethylene vinyl acetate (EVA) as a candidate polymer for thin-film passive sampling in waters of marine environments. Log K{sub EVA-W} partition coefficients correlate well (r{sup 2} = 0.87) with Log K{sub OW} values for selected pesticides and polychlorinated biphenyls (PCBs) where Log K{sub EVA-W} = 1.04 Log K{sub OW} + 0.22. EVA is a suitable polymer for passive sampling due to both its high affinity for organic compounds and its ease of coating at sub-micron film thicknesses on various substrates. Twelve-day field deployments were effective in detecting target compounds with good precision making EVA a potential multi-media fugacity meter. - Research highlights: Calibration and field testing of a thin-film passive sampler in marine systems. Ethylene vinyl acetate (EVA) is effective for a wide spectrum of organic compounds. EVA performs with high precision and reproducibility. EVA is effective in marine systems at environmentally relevant concentrations. EVA is recommended as a multi-media fugacity meter for environmental applications. - An ethylene vinyl acetate (EVA), thin-film passive sampler for the detection of organic compounds in marine environments is calibrated and field tested.

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. A New Time Calibration Method for Switched-capacitor-array-based Waveform Samplers.

    Science.gov (United States)

    Kim, H; Chen, C-T; Eclov, N; Ronzhin, A; Murat, P; Ramberg, E; Los, S; Moses, W; Choong, W-S; Kao, C-M

    2014-12-11

    We have developed a new time calibration method for the DRS4 waveform sampler that enables us to precisely measure the non-uniform sampling interval inherent in the switched-capacitor cells of the DRS4. The method uses the proportionality between the differential amplitude and sampling interval of adjacent switched-capacitor cells responding to a sawtooth-shape pulse. In the experiment, a sawtooth-shape pulse with a 40 ns period generated by a Tektronix AWG7102 is fed to a DRS4 evaluation board for calibrating the sampling intervals of all 1024 cells individually. The electronic time resolution of the DRS4 evaluation board with the new time calibration is measured to be ~2.4 ps RMS by using two simultaneous Gaussian pulses with 2.35 ns full-width at half-maximum and applying a Gaussian fit. The time resolution dependencies on the time difference with the new time calibration are measured and compared to results obtained by another method. The new method could be applicable for other switched-capacitor-array technology-based waveform samplers for precise time calibration.

  12. Prototype particulate stack sampler with single-cut nozzle and microcomputer calculating/display system

    International Nuclear Information System (INIS)

    Eler, J.C.; Littlefield, L.G.; Tillery, M.I.

    1979-01-01

    A prototype particulate stack sampler (PPSS) has been developed to improve on the existing EPA Method 5 sampling apparatus. Its primary features are (1) higher sampling rate (56 1/min); (2) display (on demand) of all required variables and calculated values by a microcomputer-based calculating and display system; (3) continuous stack gas moisture determination; (4) a virtual impactor nozzle with 3 μm mass median diameter cutpoint which collects fine and coarse particle fractions on separate glass fiber filters; (5) a variable-area inlet to maintain isokinetic sampling conditions; and (6) conversion to stainless steel components from the glass specified by EPA Method 5. The basic sampling techniques of EPA Method 5 have been 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 a collection efficiency which is less than 77% and significant wall losses. This is primarily due to lack of symmetry in this rectangular jet impactor and short transition lengths dictated by physical design constraints (required passage of the nozzle through a 7.6 cm (3 in) diameter stack port). Electronic components have shown acceptable service in laboratory testing although no field testing of the prototype under a broad range of temperature, humidity, and SO 2 concentration has been undertaken

  13. Development and evaluation of an impactor sampler for radioactive aerosol particles

    International Nuclear Information System (INIS)

    Sorimachi, Atsuyuki; Kranrod, Chutima; Chantrarayotha, Supitcha; Tokonami, Shinji

    2008-01-01

    This sampler consists of one impaction stage, which allows separation of airborne particles by 1 μm particle size cut-off point with a 50% probability of impaction, followed by a back-up filter at a flow rate of 1 L min -1 . The particles size more than and less than 1 μm-diameter are collected on the impactor plate at the nozzle side and on the filter, respectively. A Cr-39 detector is mounted on the filter sides of the impaction plate; α particles emitted from the particles less than 1 μm-diameter are counted with the Cr-39 detectors. In order to separate α particles emitted from radon, thoron and their progeny, the Cr-39 detectors are covered with aluminum-vaporized Mylar films. The total thickness of films is adjusted to let their α particles impinge on the Cr-39 detectors. Laboratory tests are going on in terms of the spectral characteristics of α particles before and after passing through the films, the count rate performance of Cr-39 detectors by α particles, the actual collection efficiency of aerosol particles on the impaction plate, and so on. This sampler may be able to supply us with an interesting technique for measuring radon and thoron progeny come from the sources of natural radiation such as the naturally occurred radioactive materials. (author)

  14. Pinus nigra and Pinus pinaster needles as passive samplers of polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Piccardo, Maria Teresa; Pala, Mauro; Bonaccurso, Bruna; Stella, Anna; Redaelli, Anna; Paola, Gaudenzio; Valerio, Federico

    2005-01-01

    Nine polycyclic aromatic hydrocarbons (PAHs) were analysed in pine needles of different ages (from 6 to 30 months) collected from two species, Pinus nigra and Pinus pinaster, in seven sites located along a transect from a suburban to a rural area of Genoa (Italy). In all sites and for both species, concentrations of more volatile PAHs (phenanthrene, anthracene, fluoranthene, pyrene) were higher than those for other less volatile PAHs, which are preferentially sorbed to airborne particulates (benzo[a]anthracene, chrysene, benzofluoranthenes, benzo[a]pyrene). Concentrations of total PAHs found in P. nigra in the rural sites were, on the average, 2.3 times higher than those in P. pinaster growing nearby. In both pine species, concentrations of volatile PAHs increased according to needle age. Annual trends of other PAHs were more variable, with a general decrease in older needles. P. pinaster needles are shown to be more reliable passive samplers, since they are more resistant to plant diseases, and considerable variation in PAH concentration was observed in P. nigra needles with moulds and fungi. - The suitability of the pine needles as passive air samplers for persistent trace organics is demonstrated

  15. Pinus nigra and Pinus pinaster needles as passive samplers of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Piccardo, Maria Teresa [Environmental Chemistry Laboratory, National Cancer Research Institute, Genova. L.go Rosanna Benzi n. 10, 16132 Genova (Italy)]. E-mail: chimamb@istge.it; Pala, Mauro [Environmental Chemistry Laboratory, National Cancer Research Institute, Genova. L.go Rosanna Benzi n. 10, 16132 Genova (Italy); Bonaccurso, Bruna [Environmental Chemistry Laboratory, National Cancer Research Institute, Genova. L.go Rosanna Benzi n. 10, 16132 Genova (Italy); Stella, Anna [Environmental Chemistry Laboratory, National Cancer Research Institute, Genova. L.go Rosanna Benzi n. 10, 16132 Genova (Italy); Redaelli, Anna [Environmental Chemistry Laboratory, National Cancer Research Institute, Genova. L.go Rosanna Benzi n. 10, 16132 Genova (Italy); Paola, Gaudenzio [Botany Department, Genoa University, C.so Dogali 1 canc., 16136 Genova (Italy); Valerio, Federico [Environmental Chemistry Laboratory, National Cancer Research Institute, Genova. L.go Rosanna Benzi n. 10, 16132 Genova (Italy)

    2005-01-01

    Nine polycyclic aromatic hydrocarbons (PAHs) were analysed in pine needles of different ages (from 6 to 30 months) collected from two species, Pinus nigra and Pinus pinaster, in seven sites located along a transect from a suburban to a rural area of Genoa (Italy). In all sites and for both species, concentrations of more volatile PAHs (phenanthrene, anthracene, fluoranthene, pyrene) were higher than those for other less volatile PAHs, which are preferentially sorbed to airborne particulates (benzo[a]anthracene, chrysene, benzofluoranthenes, benzo[a]pyrene). Concentrations of total PAHs found in P. nigra in the rural sites were, on the average, 2.3 times higher than those in P. pinaster growing nearby. In both pine species, concentrations of volatile PAHs increased according to needle age. Annual trends of other PAHs were more variable, with a general decrease in older needles. P. pinaster needles are shown to be more reliable passive samplers, since they are more resistant to plant diseases, and considerable variation in PAH concentration was observed in P. nigra needles with moulds and fungi. - The suitability of the pine needles as passive air samplers for persistent trace organics is demonstrated.

  16. Field monitoring of volatile organic compounds using passive air samplers in an industrial city in Japan

    International Nuclear Information System (INIS)

    Kume, Kazunari; Ohura, Takeshi; Amagai, Takashi; Fusaya, Masahiro

    2008-01-01

    Highly portable, sensitive, and selective passive air samplers were used to investigate ambient volatile organic compound (VOC) levels at multiple sampling sites in an industrial city, Fuji, Japan. We determined the spatial distributions of 27 species of VOCs in three campaigns: Mar (cold season), May (warm season), and Nov (mild season) of 2004. In all campaigns, toluene (geometric mean concentration, 14.0 μg/m 3 ) was the most abundant VOC, followed by acetaldehyde (4.76 μg/m 3 ), and formaldehyde (2.58 μg/m 3 ). The spatial distributions for certain VOCs showed characteristic patterns: high concentrations of benzene and formaldehyde were typically found along major roads, whereas high concentrations of toluene and tetrachloroethylene (PCE) were usually found near factories. The spatial distribution of PCE observed was extremely consistent with the diffusion pattern calculated from Pollutant Release and Transfer Register data and meteorological data, indicated that passive air samplers are useful for determining the sources and distributions of ambient VOCs. - Passive air samplings with hood are useful for determining the identities, sources, and distributions of ambient VOC pollutants

  17. Auto-Gopher: A Wireline Deep Sampler Driven by Piezoelectric Percussive Actuator and EM Rotary Motor

    Science.gov (United States)

    Badescu, Mircea; Ressa, Aaron; Jae Lee, Hyeong; Bar-Cohen, Yoseph; Sherrit, Stewart; Zacny, Kris; Paulsen, Gale L.; Beegle, Luther; Bao, Xiaoqi

    2013-01-01

    The ability to penetrate subsurfaces and perform sample acquisition at depth of meters may be critical for future NASA in-situ exploration missions to bodies in the solar system, including Mars and Europa. A corer/sampler was developed with the goal of enabling acquisition of samples from depths of several meters where if used on Mars would be beyond the oxidized and sterilized zone. For this purpose, we developed a rotary-hammering coring drill, called Auto-Gopher, which employs a piezoelectric actuated percussive mechanism for breaking formations and an electric motor that rotates the bit to remove the powdered cuttings. This sampler is a wireline mechanism that can be fed into and retrieved from the drilled hole using a winch and a cable. It includes an inchworm anchoring mechanism allowing the drill advancement and weight on bit control without twisting the reeling and power cables. The penetration rate is being optimized by simultaneously activating the percussive and rotary motions of the Auto-Gopher. The percussive mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) mechanism that is driven by piezoelectric stack and that was demonstrated to require low axial preload. The design and fabrication of this device were presented in previous publications. This paper presents the results of laboratory and field tests and lessons learned from this development.

  18. Development of a sensitive passive sampler using indigotrisulfonate for the determination of tropospheric ozone.

    Science.gov (United States)

    Garcia, Gabriel; Allen, Andrew George; Cardoso, Arnaldo Alves

    2010-06-01

    A new sampling and analytical design for measurement of ambient ozone is presented. The procedure is based on ozone absorption and decoloration (at 600 nm) of indigotrisulfonate dye, where ozone adds itself across the carbon-carbon double bond of the indigo. A mean relative standard deviation of 8.6% was obtained using samplers exposed in triplicate, and a correlation coefficient (r) of 0.957 was achieved in parallel measurements using the samplers and a commercial UV ozone instrument. The devices were evaluated in a measurement campaign, mapping spatial and temporal trends of ozone concentrations in a region of southeast Brazil strongly influenced by seasonal agricultural biomass burning, with associated emissions of ozone precursors. Ozone concentrations were highest in rural areas and lowest at an urban site, due to formation during downwind transport and short-term depletion due to titration with nitric oxide. Ozone concentrations showed strong seasonal trends, due to the influences of precursor emissions, relative humidity and solar radiation intensity. Advantages of the technique include ease and speed of use, the ready availability of components, and excellent sensitivity. Achievable temporal resolution of ozone concentrations is 8 hours at an ambient ozone concentration of 3.8 ppb, or 2 hours at a concentration of 15.2 ppb.

  19. Method development for analysis of urban dust using scanning electron microscopy with energy dispersive x-ray spectrometry to detect the possible presence of world trade center dust constituents

    Science.gov (United States)

    Bern, A.M.; Lowers, H.A.; Meeker, G.P.; Rosati, J.A.

    2009-01-01

    The collapse of the World Trade Center Towers on September 11, 2001, sent dust and debris across much of Manhattan and in the surrounding areas. Indoor and outdoor dust samples were collected and characterized by U.S. Geological Survey (USGS) scientists using scanning electron microscopy with energy-dispersive spectrometry (SEM/EDS). From this characterization, the U.S. Environmental Protection Agency and USGS developed a particulate screening method to determine the presence of residual World Trade Center dust in the indoor environment using slag wool as a primary "signature". The method describes a procedure that includes splitting, ashing, and sieving of collected dust. From one split, a 10 mg/mL dust/ isopropanol suspension was prepared and 10-30 ??L aliquots of the suspension placed on an SEM substrate. Analyses were performed using SEM/EDS manual point counting for slag wool fibers. Poisson regression was used to identify some of the sources of uncertainty, which are directly related to the small number of fibers present on each sample stub. Preliminary results indicate that the procedure is promising for screening urban background dust for the presence of WTC dust. Consistent sample preparation of reference materials and samples must be performed by each laboratory wishing to use this method to obtain meaningful and accurate results. ?? 2009 American Chemical Society.

  20. Collisionless damping of nonlinear dust ion acoustic wave due to dust charge fluctuation

    International Nuclear Information System (INIS)

    Ghosh, Samiran; Chaudhuri, Tushar K.; Sarkar, Susmita; Khan, Manoranjan; Gupta, M.R.

    2002-01-01

    A dissipation mechanism for the damping of the nonlinear dust ion acoustic wave in a collisionless dusty plasma consisting of nonthermal electrons, ions, and variable charge dust grains has been investigated. It is shown that the collisionless damping due to dust charge fluctuation causes the nonlinear dust ion acoustic wave propagation to be described by the damped Korteweg-de Vries equation. Due to the presence of nonthermal electrons, the dust ion acoustic wave admits both positive and negative potential and it suffers less damping than the dust acoustic wave, which admits only negative potential

  1. Respiratory effects of borax dust.

    Science.gov (United States)

    Garabrant, D H; Bernstein, L; Peters, J M; Smith, T J; Wright, W E

    1985-12-01

    The relation of respiratory symptoms, pulmonary function, and abnormalities of chest radiographs to estimated exposures of borax dust has been investigated in a cross sectional study of 629 actively employed borax workers. Ninety three per cent of the eligible workers participated in the study and exposures ranged from 1.1 mg/m3 to 14.6 mg/m3. Symptoms of acute respiratory irritation such as dryness of the mouth, nose, or throat, dry cough, nose bleeds, sore throat, productive cough, shortness of breath, and chest tightness were related to exposures of 4.0 mg/m3 or more, and were infrequent at exposures of 1.1 mg/m3. Symptoms of persistent respiratory irritation meeting the definition of chronic simple bronchitis were related to exposure among non-smokers. Decrements in the FEV1 as a percentage of predicted were seen among smokers who had heavy cumulative borax exposures (greater than or equal to 80 mg/m3 years) but were not seen among less exposed smokers or among non-smokers. Radiographic abnormalities were uncommon and were not related to dust exposure. Borax dust appears to act as a simple respiratory irritant and perhaps causes small changes in the FEV1 among smokers who are heavily exposed.

  2. Validation of ammonia diffusive and active samplers in a controlled atmosphere test facility using traceable Primary Standard Gas Mixtures

    Science.gov (United States)

    Martin, Nicholas A.; Ferracci, Valerio; Cassidy, Nathan; Hook, Josh; Battersby, Ross M.; Tang, Yuk S.; Stevens, Amy C. M.; Jones, Matthew R.; Braban, Christine F.; Gates, Linda; Hangartner, Markus; Stoll, Jean-Marc; Sacco, Paolo; Pagani, Diego; Hoffnagle, John A.

    2017-04-01

    Intensive animal farming, the increased use of fertilizers, and certain industrial processes are believed to be responsible for the observed increases in the amount fraction of ammonia (NH3) found in Europe. NH3 contributes to eutrophication and acidification of land and freshwater, potentially leading to a loss of biodiversity and undesirable changes to the ecosystem. It also contributes to the formation of secondary particulate matter (PM) formation, which is associated with poor air quality and adverse health outcomes. Measurements of ambient ammonia are principally carried out with low-cost diffusive samplers or by active sampling with denuders, with each method delivering time-integrated values over the monitoring period. However, such techniques have not yet been extensively validated. The goal of this work was to provide improvements in the metrological traceability through the determination of NH3 diffusive sampling rates. Five different designs of commercial diffusive samplers (FSM Radiello radial sampler, Gradko diffusion tube, Gradko DIFRAM-400, Passam ammonia sampler, and CEH ALPHA sampler) were employed, together with a pumped denuder sampler (CEH DELTA denuder) for comparison. All devices were simultaneously exposed for either 28 days or 14 days (dependent on sampler type) in a controlled atmosphere test facility (CATFAC) containing traceable amount fractions of humidified ammonia using new stable ammonia Primary Standard Gas Mixtures developed by gravimetry at NPL, under a wide range of conditions that are relevant to ambient monitoring. Online continuous monitoring of the ammonia test atmospheres was carried out by extractive sampling, employing a calibrated cavity ring-down spectrometer, which had been modified to account for cross interference by water vapour. Each manufacturer extracted the captured ammonia on the exposed samplers in the form of ammonium (NH4+) using their own accredited traceable wet chemical techniques, and then reported data

  3. Evaluation of sampling inhalable PM10 particulate matter (≤ 10 μm) using co-located high volume samplers

    International Nuclear Information System (INIS)

    Rajoy, R R S; Dias, J W C; Rego, E C P; Netto, A D Pereira

    2015-01-01

    This paper presents the results of the determination of the concentrations of atmospheric particulate matter ≤ 10 μm (PM10), collected simultaneously by six PM10 high volume samplers from two different manufacturers installed in the same location. Fifteen samples of 24 h were obtained with each equipment at a selected urban area of Rio de Janeiro city. The concentration of PM10 ranged between 10.73 and 54.04 μg m −3 . The samplers were considered comparable to each other, as the adopted methodology presented good repeatability

  4. Dust-Tolerant Intelligent Electrical Connection System

    Science.gov (United States)

    Lewis, Mark; Dokos, Adam; Perotti, Jose; Calle, Carlos; Mueller, Robert; Bastin, Gary; Carlson, Jeffrey; Townsend, Ivan, III; Immer, Chirstopher; Medelius, Pedro

    2012-01-01

    Faults in wiring systems are a serious concern for the aerospace and aeronautic (commercial, military, and civilian) industries. Circuit failures and vehicle accidents have occurred and have been attributed to faulty wiring created by open and/or short circuits. Often, such circuit failures occur due to vibration during vehicle launch or operation. Therefore, developing non-intrusive fault-tolerant techniques is necessary to detect circuit faults and automatically route signals through alternate recovery paths while the vehicle or lunar surface systems equipment is in operation. Electrical connector concepts combining dust mitigation strategies and cable diagnostic technologies have significant application for lunar and Martian surface systems, as well as for dusty terrestrial applications. The dust-tolerant intelligent electrical connection system has several novel concepts and unique features. It combines intelligent cable diagnostics (health monitoring) and automatic circuit routing capabilities into a dust-tolerant electrical umbilical. It retrofits a clamshell protective dust cover to an existing connector for reduced gravity operation, and features a universal connector housing with three styles of dust protection: inverted cap, rotating cap, and clamshell. It uses a self-healing membrane as a dust barrier for electrical connectors where required, while also combining lotus leaf technology for applications where a dust-resistant coating providing low surface tension is needed to mitigate Van der Waals forces, thereby disallowing dust particle adhesion to connector surfaces. It also permits using a ruggedized iris mechanism with an embedded electrodynamic dust shield as a dust barrier for electrical connectors where required.

  5. Ocular toxicity of authentic lunar dust.

    Science.gov (United States)

    Meyers, Valerie E; Garcìa, Hector D; Monds, Kathryn; Cooper, Bonnie L; James, John T

    2012-07-20

    Dust exposure is a well-known occupational hazard for terrestrial workers and astronauts alike and will continue to be a concern as humankind pursues exploration and habitation of objects beyond Earth. Humankind's limited exploration experience with the Apollo Program indicates that exposure to dust will be unavoidable. Therefore, NASA must assess potential toxicity and recommend appropriate mitigation measures to ensure that explorers are adequately protected. Visual acuity is critical during exploration activities and operations aboard spacecraft. Therefore, the present research was performed to ascertain the ocular toxicity of authentic lunar dust. Small (mean particle diameter = 2.9 ± 1.0 μm), reactive lunar dust particles were produced by grinding bulk dust under ultrapure nitrogen conditions. Chemical reactivity and cytotoxicity testing were performed using the commercially available EpiOcularTM assay. Subsequent in vivo Draize testing utilized a larger size fraction of unground lunar dust that is more relevant to ocular exposures (particles lunar dust was minimally irritating. Minor irritation of the upper eyelids was noted at the 1-hour observation point, but these effects resolved within 24 hours. In addition, no corneal scratching was observed using fluorescein stain. Low-titanium mare lunar dust is minimally irritating to the eyes and is considered a nuisance dust for ocular exposure. No special precautions are recommended to protect against ocular exposures, but fully shielded goggles may be used if dust becomes a nuisance.

  6. Assessment of exposure to composite nanomaterials and development of a personal respiratory deposition sampler for nanoparticles

    Science.gov (United States)

    Cena, Lorenzo

    2011-12-01

    -fiber efficiency of the screens calculated from experimental data was in good agreement with that estimated from theory for particles between 40 and 150 nm but deviated from theory for particles outside of this range. New coefficients for the single-fiber efficiency model were identified that minimized the sum of square error (SSE) between the experimental values and those estimated with the model. Compared to the original theory, the SSE calculated using the modified theory was at least threefold lower for all screens and flow rates. Since nylon fibers produce no significant spectral interference when ashed for spectrometric examination, the ability to accurately estimate collection efficiency of submicrometer particles makes nylon mesh screens an attractive collection substrate for nanoparticles. In the third study, laboratory experiments were conducted to develop a novel nanoparticle respiratory deposition (NRD) sampler that selectively collects nanoparticles in a worker's breathing zone apart from larger particles. The NRD sampler consists of a respirable cyclone fitted with an impactor and a diffusion stage containing eight nylon-mesh screens. A sampling criterion for nano-particulate matter (NPM) was developed and set as the target for the collection efficiency of the NRD sampler. The sampler operates at 2.5 Lpm and fits on a worker's lapel. The cut-off diameter of the impactor was experimentally measured to be 300 nm with a sharpness of 1.53. Loading at typical workplace levels was found to have no significant effect (2-way ANOVA, p=0.257) on the performance of the impactor. The effective deposition of particles onto the diffusion stage was found to match the NPM criterion, showing that a sample collected with the NRD sampler represents the concentration of nanoparticles deposited in the human respiratory system.

  7. Dust characterisation for hot gas filters

    Energy Technology Data Exchange (ETDEWEB)

    Dockter, B.; Erickson, T.; Henderson, A.; Hurley, J.; Kuehnel, V.; Katrinak, K.; Nowok, J.; O`Keefe, C.; O`Leary, E.; Swanson, M.; Watne, T. [University of North Dakota, Grand Forks, ND (United States). Energy and Environmental Research Center (UNDEERC)

    1998-03-01

    Hot gas filtration to remove particulates from the gas flow upstream of the gas turbine is critical to the development of many of the advanced coal-fired power generation technologies such as the Air Blown Gasification Cycle (ABGC), a hybrid gasification combined cycle being developed in the UK. Ceramic candle filters are considered the most promising technology for this purpose. Problems of mechanical failure and of `difficult-to-clean` dusts causing high pressure losses across the filter elements need to be solved. The project investigated the behaviour of high-temperature filter dusts, and the factors determining the ease with which they can be removed from filters. The high-temperature behaviour of dusts from both combustion and gasification systems was investigated. Dust samples were obtained from full-scale demonstration and pilot-scale plant operating around the world. Dust samples were also produced from a variety of coals, and under several different operating conditions, on UNDEERC`s pilot-scale reactor. Key factors affecting dust behaviour were examined, including: the rates of tensile strength developing in dust cakes; the thermochemical equilibria pertaining under filtration conditions; dust adhesivity on representative filter materials; and the build-up and cleaning behaviour of dusts on representative filter candles. The results obtained confirmed the importance of dust temperature, dust cake porosity, cake liquid content, and particle size distribution in determining the strength of a dust cake. An algorithm was developed to indicate the likely sticking propensity of dusts as a function of coal and sorbent composition and combustion conditions. This algorithm was incorporated into a computer package which can be used to judge the degree of difficulty in filter cleaning that can be expected to arise in a real plant based on operating parameters and coal analyzes. 6 figs.

  8. Sources and distribution of organic compounds using passive samplers in Lake Mead National Recreation Area, Nevada and Arizona, and their implications for potential effects on aquatic biota.

    Science.gov (United States)

    Rosen, Michael R.; Alvarez, David A.; Goodbred, Steven L.; Leiker, Thomas J.; Patino, Reynaldo

    2009-01-01

    Th e delineation of lateral and vertical gradients of organic contaminants in lakes is hampered by low concentrations and nondetection of many organic compounds in water. Passive samplers (semipermeable membrane devices [SPMDs] and polar organic chemical integrative samplers [POCIS]) are well suited for assessing gradients because they can detect synthetic organic

  9. Determination of respirable-sized crystalline silica in different ambient environments in the United Kingdom with a mobile high flow rate sampler utilising porous foams to achieve the required particle size selection

    Science.gov (United States)

    Stacey, Peter; Thorpe, Andrew; Roberts, Paul; Butler, Owen

    2018-06-01

    Inhalation of respirable crystalline silica (RCS) can cause diseases including silicosis and cancer. Levels of RCS close to an emission source are measured but little is known about the wider ambient exposure from industry emissions or natural sources. The aim of this work is to report the RCS concentrations obtained from a variety of ambient environments using a new mobile respirable (PM4) sampler. A mobile battery powered high flow rate (52 L min-1) sampler was developed and evaluated for particulate aerosol sampling employing foams to select the respirable particle size fraction. Sampling was conducted in the United Kingdom at site boundaries surrounding seven urban construction and demolition and five sand quarry sites. These are compared with data from twelve urban aerosol samples and from repeat measurements from a base line study at a single rural site. The 50% particle size penetration (d50) through the foam was 4.3 μm. Over 85% of predict bias values were with ±10% of the respirable convention, which is based on a log normal curve. Results for RCS from all construction and quarry activities are generally low with a 95 th percentile of 11 μg m-3. Eighty percent of results were less than the health benchmark value of 3 μg m-3 used in some states in America for ambient concentrations. The power cutting of brick and the largest demolition activities gave the highest construction levels. Measured urban background RCS levels were typically below 0.3 μg m-3 and the median RCS level, at a rural background location, was 0.02 μg m-3. These reported ambient RCS concentrations may provide useful baseline values to assess the wider impact of fugitive, RCS containing, dust emissions into the wider environment.

  10. Control of coal-dust in mines. Second edition. Bor'ba s ugol'noi i porodnoi pyl'yu v shakhtakh

    Energy Technology Data Exchange (ETDEWEB)

    Pemrukhin, P.M.; Grodel, G.S.; Zhilyaev, N.I.; Korenev, A.P.; Krivokhizha, B.M.; Kul' bachnyi, A.N.; Lyubimoba, A.I.; Medvedev, E.N.; Yaremachenko, P.P.

    1981-01-01

    An examination is made of problems concerned with over-all removal of dust from the air in mines. A description is given of physical and physico-chemical properties of ore mine dust that are of importance to evaluating processes in the formation, propagation and suppression of dust. Results are given for theoretical and on-site studies of dust aerodynamics in mines. A presentation is made of contemporary measures for controlling coal and rock dust in mines as well as means and methods of controlling air dust-level. Technical characteristics are given for new instruments for measuring air dust level. Brief data are given on preliminary wetting of coal in a massif, and a discussion is made of theoretical and practical problems related to hydro-dedusting, dust suppression, and dust removal during the operation of mining machinery as well as instruments for dedusting air on the surface complex of a mine. The book is intended for engineering-technical personnel in coal mines, design-planning and scientific-research institutes. 52 references, 61 tables.

  11. House dust in seven Danish offices

    Science.gov (United States)

    Mølhave, L.; Schneider, T.; Kjærgaard, S. K.; Larsen, L.; Norn, S.; Jørgensen, O.

    Floor dust from Danish offices was collected and analyzed. The dust was to be used in an exposure experiment. The dust was analyzed to show the composition of the dust which can be a source of airborne dust indoors. About 11 kg of dust from vacuum cleaner bags from seven Danish office buildings with about 1047 occupants (12 751 m 2) was processed according to a standardized procedure yielding 5.5 kg of processed bulk dust. The bulk dust contained 130.000-160.000 CFU g -1 microorganisms and 71.000-90.000 CFU g -1 microfungi. The content of culturable microfungi was 65-123 CFU 30 g -1 dust. The content of endotoxins ranged from 5.06-7.24 EU g -1 (1.45 ng g -1 to 1.01 ng g -1). Allergens (ng g -1) were from 147-159 (Mite), 395-746 (dog) and 103-330 (cat). The macro molecular organic compounds (the MOD-content) varied from 7.8-9.8 mg g -1. The threshold of release of histamine from basophil leukocytes provoked by the bulk dust was between 0.3 and 1.0 mg ml -1. The water content was 2% (WGT) and the organic fraction 33%. 6.5-5.9% (dry) was water soluble. The fiber content was less than 0.2-1.5% (WGT) and the desorbable VOCs was 176-319 μg g -1. Most of the VOC were aldehydes. However, softeners for plastic (DBP and DEHP) were present. The chemical composition includes human and animal skin fragments, paper fibers, glass wool, wood and textilefibers and inorganic and metal particles. The sizes ranged from 0.001-1 mm and the average specific density was 1.0 g m -3. The bulk dust was resuspended and injected into an exposure chamber. The airborne dust was sampled and analyzed to illustrate the exposures that can result from sedimented dirt and dust. The airborne dust resulting from the bulk dust reached concentrations ranging from 0.26-0.75 mg m -3 in average contained 300-170 CFU m -3. The organic fraction was from 55-70% and the water content about 2.5% (WGT). The content of the dust was compared to the similar results reported in the literature and its toxic potency is

  12. Lidar measurements of boundary layer depolarization and CCSEM-EDX compositional analysis of airborne particles on collocated passive samplers throughout the forest canopy during the 2016 airborne pollen season at UMBS, Pellston, MI

    Science.gov (United States)

    Wozniak, M. C.; Steiner, A.; Ault, A. P.; Kort, E. A.; Lersch, T.; Casuccio, G.

    2017-12-01

    Observations of airborne pollen are typically made with volumetric samplers that obtain a time-averaged pollen concentration at a single point. While spatial variations in surface pollen concentrations may be known with these samplers given multiple sampling sites, real-time boundary layer transport of pollen grains cannot be determined except by particle dispersion or tracer transport models. Recently, light detection and ranging (lidar) techniques, such as depolarization, have been used to measure pollen transport and optical properties throughout the boundary layer over time. Here, we use a ground-based micro-pulse lidar (MPL) to observe boundary layer vertical profiles before, during and after the peak anemophilous (wind-driven) pollen season. The lidar depolarization ratio is measured in tandem with the normalized R-squared backscatter (NRB) intensity to determine the contribution of aspherical particles to the scatterers present throughout the boundary layer. Measurements are taken from April 15 - July 12, 2016 at the University of Michigan Biological Station (UMBS) PROPHET outdoor research lab and tower within a largely forested region. UMBS is dominated by Acer rubrum, Betula papyrifera, Pinus resinosa, Quercus rubra and Pinus strobus, all of which began flowering on 4/19, 5/3, 5/25, 5/25 and 6/14, respectively. Temperature, relative humidity and wind speed measured on site determine daytime conditions conducive to pollen dispersion from flowers. Lidar depolarization ratios between 0.08-0.14 and higher are observed in the daytime boundary layer on days shortly after the flowering dates of the aforementioned species, elevated above the background level of 0.06 or less. Lidar observations are supplemented with aerosol compositional analysis determined by computer-controlled scanning electron microscopy and energy-dispersive X-ray spectroscopy (CCSEM-EDX) on passive sampler data from below, within and above the forest canopy at PROPHET tower. Particles are

  13. Characterization of high concentration dust generator

    International Nuclear Information System (INIS)

    Shimura, Toichiro; Yokochi, Akira

    1999-01-01

    This paper describes the development of fluidized bed type high concentration dust generator that keeps for long period dust concentration range of about 10 mg/m 3 for the study of working place monitoring system and evaluation of respirator. The generator is keeping constant powder in fluidized bed for keeping the dust concentration. It is necessary to keep constant feeding rate of powder in order to keep the quantity of dust in the fluidized bed. Our generator enables to obtain constant feeding rate by a screw feeder and by using mixed powder with fluidising particles (glass beads) before feeding. The generator produces high concentration dust of 11.3 mg/m 3 ± 1.0 mg/m 3 for about 5 hours and keeps the dust size 4.2-4.6 μm in mass median aerodynamic diameter with reasonable reproducibility. (author)

  14. Molecules and dust in Cassiopeia A

    DEFF Research Database (Denmark)

    Biscaro, Chiara; Cherchneff, Isabelle

    2016-01-01

    We study the dust evolution in the supernova remnant Cassiopeia A. We follow the processing of dust grains that formed in the Type II-b supernova ejecta by modelling the sputtering of grains. The dust is located in dense ejecta clumps that are crossed by the reverse shock. We also investigate......-rich clumps that correspond to the outermost carbon-rich ejecta zone. We consider the various dust components that form in the supernova, several reverse shock velocities and inter-clump gas temperatures, and derive grain-size distributions and masses for the dust as a function of time. Both non...... and size, and the shock velocity in the clump. A Type II-b SN forms small grains that are sputtered within the clumps and in the inter-clump medium. For Cas A, silicate grains do not survive thermal sputtering in the inter-clump medium, while alumina, silicon carbide, and carbon dust may survive...

  15. Active Dust Experiment in the Mesosphere

    International Nuclear Information System (INIS)

    Norberg, Carol; Pellinen-Wannberg, Asta

    2008-01-01

    The mesosphere stretches from an altitude of about 50 to 90 km above the Earth's surface. Meteors entering the Earth's atmosphere are believed to ablate and hence give rise to a thin layer of dust particles in the upper part of the Earth's mesosphere. It seems that the dust is most dense in a layer that lies between 80 and 90 km. The dust particles are thought to have sizes of a few to tens of nanometers. Efforts have been made to measure these particles using rockets and radar techniques with limited success. We propose to release dust into the mesosphere over northern Sweden at a height of about 90 km and observe the released dust using the EISCAT radar system. The dust will be launched from the Swedish Space Corporation Esrange Space Centre on a single-stage Improved-Orion rocket that will be launched so that its flight path will be in the radar field of view.

  16. Formation and dissociation of dust molecules in dusty plasma

    International Nuclear Information System (INIS)

    Yan Jia; Feng Fan; Liu Fucheng; Dong Lifang; He Yafeng

    2016-01-01

    Dust molecules are observed in a dusty plasma experiment. By using measurements with high spatial resolution, the formation and dissociation of the dust molecules are studied. The ion cloud in the wake of an upper dust grain attracts the lower dust grain nearby. When the interparticle distance between the upper dust grain and the lower one is less than a critical value, the two dust grains would form a dust molecule. The upper dust grain always leads the lower one as they travel. When the interparticle distance between them is larger than the critical value, the dust molecule would dissociate. (paper)

  17. Trace metals in urban road dust

    International Nuclear Information System (INIS)

    Randazzo, Loredana Antonella; Dongarra, Gaetano; Manno, Emanuela; Varrica, Daniela

    2006-01-01

    Heavy metals associated with urban road dust is a matter for concern as they may have serious effects on biological systems. The bioavailability and potential toxicity of metals bound to urban dust is related to the specific chemical form of the element. In the present article are reported the determinations and chemical speciation of As, Ba, Cr, Cu, Mo, Ni, Pb and Zn in six samples of road dust collected within the urban centre and the outskirts of Palermo [it

  18. Cylindrical dust acoustic waves with transverse perturbation

    International Nuclear Information System (INIS)

    Xue Jukui

    2003-01-01

    The nonlinear dust acoustic waves in dusty plasmas with the combined effects of bounded cylindrical geometry and the transverse perturbation are studied. Using the perturbation method, a cylindrical Kadomtsev-Petviashvili (CKP) equation that describes the dust acoustic waves is deduced for the first time. A particular solution of this CKP equation is also obtained. It is shown that the dust acoustic solitary waves can exist in the CKP equation

  19. The control and prevention of dust explosions

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    Papers presented discussed: explosion characteristics and hybrid mixtures explosion characteristics and influencing factors, propagation of dust explosions in ducts, prevention of dust explosions, desensitization, explosion-proof type of construction, explosion pressure relief, optical flame barriers, slide-valves for explosion protection, Ventex explosion barrier valves, grinding and mixing plants, spray driers, dust explosions in silos, and explosion-proof bucket elevators. One paper has been abstracted separately.

  20. Modeling the Dynamics of Comet Hale-Bopp's Dust at Large Heliocentric Distances

    Science.gov (United States)

    Kramer, Emily A.; Fernandez, Y. R.; Kelley, M. S.; Woodney, L. M.; Lisse, C. M.

    2010-10-01

    Comet Hale-Bopp has provided an unprecedented opportunity to observe a bright comet over a wide range of heliocentric distances. We present here Spitzer Space Telescope observations of Hale-Bopp from 2005 and 2008 that show a distinct coma and tail, which is uncommon given its heliocentric distance -- 21.6 AU and 27.2 AU, respectively. These 24 um images (obtained with MIPS, the Multiband Imaging Photometer for Spitzer) show thermal emission from the dust, and are being studied using dynamical models [1, 2] to explain the dust morphology and constrain the dust's properties. Preliminary work suggests that the motion of the dust cannot be solely due to the effects of gravity and radiation pressure. We investigate the role of other possible driving forces, including the so-called rocket force [3]. Our initial analysis also shows that: (1) there is no trail lying along the orbit plane, as Spitzer saw for many other comets [4]; (2) the position angle of the tail changed by about 50º between 2005 and 2008; (3) the faintness and shape of the tail in 2008 compared to 2005 cannot solely be due to the change in observing geometry. These points suggest that even though Hale-Bopp is far from the Sun its tail is made of relatively recently-released grains. Our science goals are to understand the comet's activity mechanism, constrain the age of the dust, find the size of the grains, and compare properties of the dust seen now to those of the dust seen in the 1990s. We acknowledge support from the NSF, NASA and the Spitzer Science Center for this work. References: [1] Kelley, M.S., et al.  2008, Icarus 193, 572, [2] Lisse, C.M., et al. 1998, ApJ 496, 971, [3] Reach, W.T., et al. 2009, Icarus 203, 571, [4] Reach, W.T., et al. 2007, Icarus 191, 298.

  1. Saharan dust - a carrier of persistent organic pollutants, metals and microbes to the Caribbean?

    Directory of Open Access Journals (Sweden)

    V.H Garrison

    2006-12-01

    Full Text Available An international team of scientists from government agencies and universities in the United States, U.S. Virgin Islands (USVI, Trinidad & Tobago, the Republic of Cape Verde, and the Republic of Mali (West Africa is working together to elucidate the role Saharan dust may play in the degradation of Caribbean ecosystems. The first step has been to identify and quantify the persistent organic pollutants (POPs, trace metals, and viable microorganisms in the atmosphere in dust source areas of West Africa, and in dust episodes at downwind sites in the eastern Atlantic (Cape Verde and the Caribbean (USVI and Trinidad & Tobago. Preliminary findings show that air samples from Mali contain a greater number of pesticides, polychlorinated biphenyls (PCBs and polycyclic aromatic hydrocarbons (PAHs and in higher concentrations than the Caribbean sites. Overall, POP concentrations were similar in USVI and Trinidad samples. Trace metal concentrations were found to be similar to crustal composition with slight enrichment of lead in Mali. To date, hundreds of cultureable micro-organisms have been identified from Mali, Cape Verde, USVI, and Trinidad air samples. The sea fan pathogen, Aspergillus sydowii, has been identified in soil from Mali and in air samples from dust events in the Caribbean. We have shown that air samples from a dust-source region contain orders of magnitude more cultureable micro-organisms per volume than air samples from dust events in the Caribbean, which in turn contain 3-to 4-fold more cultureable microbes than during non-dust conditions. Rev. Biol. Trop. 54 (Suppl. 3: 9-21. Epub 2007 Jan. 15.

  2. Dust control at Yucca Mountain project

    International Nuclear Information System (INIS)

    Kissell, F.; Jurani, R.; Dresel, R.; Reaux, C.

    1999-01-01

    This report describes actions taken to control silica dust at the Yucca Mountain Exploratory Studies Facility, a tunnel located in Southern Nevada that is part of a scientific program to determine site suitability for a potential nuclear waste repository. The rock is a volcanic tuff containing significant percentages of both quartz and cristobalite. Water use for dust control was limited because of scientific test requirements, and this limitation made dust control a difficult task. Results are reported for two drifts, called the Main Loop Drift and the Cross Drift. In the Main Loop Drift, dust surveys and tracer gas tests indicated that air leakage from the TBM head, the primary ventilation duct, and movement of the conveyor belt were all significant sources of dust. Conventional dust control approaches yielded no significant reductions in dust levels. A novel alternative was to install an air cleaning station on a rear deck of the TBM trailing gear. It filtered dust from the contaminated intake air and discharged clean air towards the front of the TBM. The practical effect was to produce dust levels below the exposure limit for all TBM locations except close to the head. In the Cross Drift, better ventilation and an extra set of dust seals on the TBM served to cut down the leakage of dust from the TBM cutter head. However, the conveyor belt was much dustier than the belt in the main loop drift. The problem originated with dirt on the bottom of the belt return side and much spillage from the belt top side. Achieving lower dust levels in hard rock tunneling operations will require new approaches as well as a more meticulous application of existing technology. Planning for dust control will require specific means to deal with dust that leaks from the TBM head, dust that originates with leaky ventilation systems, and dust that comes from conveyor belts. Also, the application of water could be more efficient if automatic controls were used to adjust the water flow

  3. Beryllium dust generation resulting from plasma bombardment

    International Nuclear Information System (INIS)

    Doerner, R.; Mays, C.

    1997-01-01

    The beryllium dust resulting from erosion of beryllium samples subjected to plasma bombardment has been measured in PISCES-B. Loose surface dust was found to be uniformly distributed throughout the device and accounts for 3% of the eroded material. A size distribution measurement of the loose surface dust shows an increasing number of particles with decreasing diameter. Beryllium coatings on surfaces with a line of sight view of the target interaction region account for an additional 33% of the eroded beryllium material. Flaking of these surface layers is observed and is thought to play a significant role in dust generation inside the vacuum vessel. (orig.)

  4. Control of dust production in ITER

    International Nuclear Information System (INIS)

    Rodriguez-Rodrigo, L.; Ciattaglia, S.; Elbez-Uzan, J.

    2006-01-01

    In the last years dust has been observed in a number of fusion devices and is being studied more in detail for understanding in particular the physical phenomena related to its formation, its composition, physical and chemical characteristics, and the amount of produced dust. The extrapolation of dust formation to ITER predicts (with large error bars), a large mass of dust production with a scattered size distribution. To evaluate the impact of dust on safety, assumptions have also been made on radionuclide inventory, and mobility in off-normal events, as well as any postulated contributions the dust may make to effluents or accidental releases. Solid activation products in structures are generally not readily mobilisable in incidental and accidental situations, so that activated dust, tritium and activated corrosions products are the important in-vessel source terms in postulated scenarios that assume a mobilisation and release of some fraction of this inventory. Such a release would require the simultaneous leak or bypass of several robust confinement barriers. Further concerns for dust may be the potential for chemical reactions between dust and coolant in the event of an in-vessel leak, and the theoretical possibility of a dust explosion, either of which could in principle cause a pressure rise that challenges one or more of the confinement barriers. Although these hazards can - and will - be controlled by other measures in the ITER design, application of the principle of Defence in Depth dictates that the dust inventory should also be minimised and controlled to prevent the potential hazard. A well-coordinated R-and-D programme is required to support this dust production control. This document provides from the safety point of view, an overview of existing data given in '' Dossier d'Options de Surete '', the first safety report presented in 2001 to the French Safety Authorities, and ITER documents; it also gathers information on status of studies on activated

  5. Efficacy of passive sampler collection for atmospheric NO2 isotopes under simulated environmental conditions.

    Science.gov (United States)

    Coughlin, Justin G; Yu, Zhongjie; Elliott, Emily M

    2017-07-30

    Nitrogen oxides or NO x (NO x = NO + NO 2 ) play an important role in air quality, atmospheric chemistry, and climate. The isotopic compositions of anthropogenic and natural NO 2 sources are wide-ranging, and they can be used to constrain sources of ambient NO 2 and associated atmospheric deposition of nitrogen compounds. While passive sample collection of NO 2 isotopes has been used in field studies to determine NO x source influences on atmospheric deposition, this approach has not been evaluated for accuracy or precision under different environmental conditions. The efficacy of NO 2 passive sampler collection for NO 2 isotopes was evaluated under varied temperature and relative humidity (RH) conditions in a dynamic flux chamber. The precision and accuracy of the filter NO 2 collection as nitrite (NO 2 - ) for isotopic analysis were determined using a reference NO 2 gas tank and through inter-calibration with a modified EPA Method 7. The bacterial denitrifer method was used to convert 20 μM of collected NO 2 - or nitrate (NO 3 - ) into N 2 O and was carried out on an Isoprime continuous flow isotope ratio mass spectrometer. δ 15 N-NO 2 values determined from passive NO 2 collection, in conditions of 11-34 °C, 1-78% RH, have an overall accuracy and precision of ±2.1 ‰, and individual run precision of ±0.6 ‰. δ 18 O-NO 2 values obtained from passive NO 2 sampler collection, under the same conditions, have an overall precision of ± 1.3 ‰. Suitable conditions for passive sampler collection of NO 2 isotopes are in environments ranging from 11 to 34 °C and 1 to 78% RH. The passive NO 2 isotope measurement technique provides an accurate method to determine variations in atmospheric δ 15 N-NO 2 values and a precise method for determining atmospheric δ 18 O-NO 2 values. The ability to measure NO 2 isotopes over spatial gradients at the same temporal resolution provides a unique perspective on the extent and seasonality of fluctuations in atmospheric NO 2

  6. Integrative Analysis of Desert Dust Size and Abundance Suggests Less Dust Climate Cooling

    Science.gov (United States)

    Kok, Jasper F.; Ridley, David A.; Zhou, Qing; Miller, Ron L.; Zhao, Chun; Heald, Colette L.; Ward, Daniel S.; Albani, Samuel; Haustein, Karsten

    2017-01-01

    Desert dust aerosols affect Earths global energy balance through interactions with radiation, clouds, and ecosystems. But the magnitudes of these effects are so uncertain that it remains unclear whether atmospheric dust has a net warming or cooling effect on global climate. Consequently, it is still uncertain whether large changes in atmospheric dust loading over the past century have slowed or accelerated anthropogenic climate change, and the climate impact of possible future alterations in dust loading is similarly disputed. Here we use an integrative analysis of dust aerosol sizes and abundance to constrain the climatic impact of dust through direct interactions with radiation. Using a combination of observational, experimental, and model data, we find that atmospheric dust is substantially coarser than represented in current climate models. Since coarse dust warms global climate, the dust direct radiative effect (DRE) is likely less cooling than the 0.4 W m superscript 2 estimated by models in a current ensemble. We constrain the dust DRE to -0.20 (-0.48 to +0.20) W m superscript 2, which suggests that the dust DRE produces only about half the cooling that current models estimate, and raises the possibility that dust DRE is actually net warming the planet.

  7. Carbohydrate and protein contents of grain dusts in relation to dust morphology.

    Science.gov (United States)

    Dashek, W V; Olenchock, S A; Mayfield, J E; Wirtz, G H; Wolz, D E; Young, C A

    1986-01-01

    Grain dusts contain a variety of materials which are potentially hazardous to the health of workers in the grain industry. Because the characterization of grain dusts is incomplete, we are defining the botanical, chemical, and microbial contents of several grain dusts collected from grain elevators in the Duluth-Superior regions of the U.S. Here, we report certain of the carbohydrate and protein contents of dusts in relation to dust morphology. Examination of the gross morphologies of the dusts revealed that, except for corn, each dust contained either husk or pericarp (seed coat in the case of flax) fragments in addition to respirable particles. When viewed with the light microscope, the fragments appeared as elongated, pointed structures. The possibility that certain of the fragments within corn, settled, and spring wheat were derived from cell walls was suggested by the detection of pentoses following colorimetric assay of neutralized 2 N trifluoroacetic acid hydrolyzates of these dusts. The presence of pentoses together with the occurrence of proteins within water washings of grain dusts suggests that glycoproteins may be present within the dusts. With scanning electron microscopy, each dust was found to consist of a distinct assortment of particles in addition to respirable particles. Small husk fragments and "trichome-like" objects were common to all but corn dust. Images FIGURE 4. FIGURE 5. PMID:3709476

  8. Combining polar organic chemical integrative samplers (POCIS) with toxicity testing to evaluate pesticide mixture effects on natural phototrophic biofilms

    International Nuclear Information System (INIS)

    Pesce, Stephane; Morin, Soizic; Lissalde, Sophie; Montuelle, Bernard; Mazzella, Nicolas

    2011-01-01

    Polar organic chemical integrative samplers (POCIS) are valuable tools in passive sampling methods for monitoring polar organic pesticides in freshwaters. Pesticides extracted from the environment using such methods can be used to toxicity tests. This study evaluated the acute effects of POCIS extracts on natural phototrophic biofilm communities. Our results demonstrate an effect of POCIS pesticide mixtures on chlorophyll a fluorescence, photosynthetic efficiency and community structure. Nevertheless, the range of biofilm responses differs according to origin of the biofilms tested, revealing spatial variations in the sensitivity of natural communities in the studied stream. Combining passive sampler extracts with community-level toxicity tests offers promising perspectives for ecological risk assessment. - Research highlights: → Polar organic chemical integrative samplers (POCIS) were used for monitoring polar organic pesticides in a contaminated river. → The acute effects of POCIS extracts were tested on natural phototrophic biofilm communities. → POCIS pesticide mixtures affected chlorophyll a fluorescence, photosynthetic efficiency and community structure. → Biofilm responses differed according to origin of the biofilms tested, revealing variations in the sensitivity of natural communities. → Combining passive sampler extracts with community-level toxicity tests offers promising perspectives for ecological risk assessment. - Pesticide mixtures extracted from POCIS can affect chl a fluorescence, photosynthetic efficiency and community structure of natural biofilms.

  9. A Field Evaluation of Performance Reference Compound Based Estimates of Cfree Using Water Column Deployed Passive Samplers

    Science.gov (United States)

    Low-Density polyethylene (LDPE) sheets are often used as passive samplers for aquatic environmental monitoring to measure the freely dissolved concentrations of hydrophobic organic contaminants (HOCs). HOCs that are freely dissolved in water (Cfree) will partition into the LDPE u...

  10. Development of a passive sampler based on a polymer inclusion membrane for total ammonia monitoring in freshwaters.

    Science.gov (United States)

    Almeida, M Inês G S; Silva, Adélia M L; Coleman, Rhys A; Pettigrove, Vincent J; Cattrall, Robert W; Kolev, Spas D

    2016-05-01

    A passive sampler for determining the time-weighted average total ammonia (i.e. molecular ammonia and the ammonium cation) concentration (C TWA) in freshwaters, which incorporated a polymer inclusion membrane (PIM) as a semi-permeable barrier separating the aqueous source solution from the receiving solution (i.e. 0.8 mol L(-1) HCl), was developed for the first time. The PIM was composed of dinonylnaphthalene sulfonic acid (DNNS) as a carrier, poly (vinyl chloride) (PVC) as a base polymer and 1-tetradecanol as a modifier. Its optimal composition was found to be 35 wt% commercial DNNS, 55 wt% PVC and 10 wt% 1-tetradecanol. The effect of environmental variables such as the water matrix, pH and temperature were also studied using synthetic freshwaters. The passive sampler was calibrated under laboratory conditions using synthetic freshwaters and exhibited a linear response within the concentration range 0.59-2.8 mg L(-1) NH4(+) (0.46-2.1 mg N L(-1)) at 20 °C. The performance of the sampler was further investigated under field conditions over 7 days. A strong correlation between spot sampling and passive sampling was achieved, thus providing a proof-of-concept for the passive sampler for reliably measuring the C(TWA) of total ammonia in freshwaters, which can be used as an indicator in tracking sources of faecal contamination in stormwater drains.

  11. Beehold : the colony of the honeybee (Apis mellifera L) as a bio-sampler for pollutants and plant pathogens

    NARCIS (Netherlands)

    Steen, van der J.J.M.

    2016-01-01

    Bio-sampling is a function of bio-indication. Bio-indication with honeybee colonies (Apis mellifera L) is where the research fields of environmental technology and apiculture overlap. The honeybees are samplers of the environment by collecting unintentionally and simultaneously, along

  12. Performance evaluation and accuracy of passive capillary samplers (PCAPs) for estimating real-time drainage water fluxes

    Science.gov (United States)

    Successful monitoring of pollutant transport through the soil profile requires accurate, reliable, and appropriate instrumentation to measure amount of drainage water or flux within the vadose layer. We evaluated the performance and accuracy of automated passive capillary wick samplers (PCAPs) for ...

  13. Selection of design parameters of diffusion barrier in a passive 222Rn sampler based on activated charcoal adsorption

    International Nuclear Information System (INIS)

    Wei Suxia

    1992-01-01

    A method concerning selection of design parameters of diffusion barrier in a passive 222 Rn sampler based on activated charcoal adsorption. The proper parameter value of diffusion barrier is obtained by means of linearization of 222 Rn adsorption versus the exposure time. Thus, the influence of temperature on measured results may be greatly decreased, and higher sensitivity of the detector may be maintained

  14. Simplified unified analysis of switched-RC passive mixers, samplers, and N -Path filters using the adjoint network

    NARCIS (Netherlands)

    Pavan, Shanthi; Klumperink, Eric A.M.

    2017-01-01

    Recent innovations in software defined CMOS radio transceiver architectures heavily rely on high linearity switched-RC sampler and passive-mixer circuits, driven by digitally programmable multiphase clocks. Although seemingly simple, the frequency domain analysis of these linear periodically time

  15. A comparison of freshwater mussels and passive samplers as indicators of heavy metal pollution in aquatic systems

    DEFF Research Database (Denmark)

    Søberg, Laila C.; Vollertsen, Jes; Nielsen, Asbjørn Haaning

    2013-01-01

    under controlled conditions in order to determine whether either system was capable of functioning as a reliable source of data on aquatic pollution. The laboratory results indicated that mussels are useful in this context. However, passive samplers will require further development to be useful since...

  16. Efficiency of Airborne Sample Analysis Platform (ASAP Bioaerosol Sampler for Pathogen Detection

    Directory of Open Access Journals (Sweden)

    Anurag eSharma

    2015-05-01

    Full Text Available 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 5×10E3 plaque-forming units (p.f.u. [2×10E5 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.

  17. Radon gas sampler for indoor and soil measurements and its applications

    International Nuclear Information System (INIS)

    Azimi-Garakani, D.; Flores, B.; Piermattei, S.; Susanna, A.F.; Seidel, J.L.; Tommasino, L.; Torri, G.

    1988-01-01

    A national large scale survey of indoor radon (based on an optimised sampling strategy) is needed in Italy to obtain average population dose for use in epidemiological studies. Since in the great majority of cases, one of the most important radon sources is the soil and rock beneath the houses, it would be interesting to combine this survey with measurements of bed-soil radon. With these objectives in mind, a new radon monitor device has been developed consisting of two etched track detectors enclosed in a heat-sealed polyethylene bag. When compared with existing techniques, this radon gas sampler presents several advantages for both indoor and outdoor measurements. As a pilot project, radon gas measurements have been carried out in hundreds of different sites and for several locations; measurements have been made for different years. Typical houses with relatively high radon concentrations have also been thoroughly investigated. (author)

  18. Empirical Statistical Power for Testing Multilocus Genotypic Effects under Unbalanced Designs Using a Gibbs Sampler

    Directory of Open Access Journals (Sweden)

    Chaeyoung Lee

    2012-11-01

    Full Text Available Epistasis that may explain a large portion of the phenotypic variation for complex economic traits of animals has been ignored in many genetic association studies. A Baysian method was introduced to draw inferences about multilocus genotypic effects based on their marginal posterior distributions by a Gibbs sampler. A simulation study was conducted to provide statistical powers under various unbalanced designs by using this method. Data were simulated by combined designs of number of loci, within genotype variance, and sample size in unbalanced designs with or without null combined genotype cells. Mean empirical statistical power was estimated for testing posterior mean estimate of combined genotype effect. A practical example for obtaining empirical statistical power estimates with a given sample size was provided under unbalanced designs. The empirical statistical powers would be useful for determining an optimal design when interactive associations of multiple loci with complex phenotypes were examined.

  19. Development and design of a line imaging spectrometer sampler (LISS) - A user manual

    DEFF Research Database (Denmark)

    Jørgensen, R.N.; Rasmussen, P.

    2002-01-01

    The objective of this report is to develop and describe the software for a Line Imaging Spectrometer Sampler (LISS) to perform measurements of spectra combined with a digital RGB photo of a measurant. Secondly this report should enable users to performmeasurements with the system. The measuring...... are developed as a Graphical User Interfaced (GUI) hosted by Matlab Release 12 from Mathworks. This GUI enables the operator to perform measurements from alldevices simultaneously together with notes specific for the measurant and store all the data in one Matlab data structure. The software includes dynamic...... exposure of the two CCD cameras ensuring optimal use of 16 bit range under unstable illuminationconditions. A routine, handling dark frame subtraction in a robust manner minimising the effect of hot pixels is also included. This report enables a novice user to perform measurements with LISS relatively easy...

  20. Evaluation of the probability distribution of intake from a single measurement on a personal air sampler

    International Nuclear Information System (INIS)

    Birchall, A.; Muirhead, C.R.; James, A.C.

    1988-01-01

    An analytical expression has been derived for the k-sum distribution, formed by summing k random variables from a lognormal population. Poisson statistics are used with this distribution to derive distribution of intake when breathing an atmosphere with a constant particle number concentration. Bayesian inference is then used to calculate the posterior probability distribution of concentrations from a given measurement. This is combined with the above intake distribution to give the probability distribution of intake resulting from a single measurement of activity made by an ideal sampler. It is shown that the probability distribution of intake is very dependent on the prior distribution used in Bayes' theorem. The usual prior assumption, that all number concentrations are equally probable, leads to an imbalance in the posterior intake distribution. This can be resolved if a new prior proportional to w -2/3 is used, where w is the expected number of particles collected. (author)