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Sample records for volume surface sampler

  1. Development of a high-volume air sampler for nanoparticles.

    Science.gov (United States)

    Hata, M; Thongyen, T; Bao, L; Hoshino, A; Otani, Y; Ikeda, T; Furuuchi, M

    2013-02-01

    As a tool to evaluate the characteristics of aerosol nano-particles, a high-volume air sampler for the collection of nano-particles was developed based on the inertial filter technology. Instead of the webbed fiber geometry of the existing inertial filter, wire mesh screens alternately layered using spacing sheets with circular holes aligned to provide multi-circular nozzles were newly devised and the separation performance of the filter was investigated experimentally. The separation performance was evaluated for a single-nozzle inertial filter at different filtration velocities. A webbed stainless steel fiber mat attached on the inlet surface of the developed inertial filter was discussed as a pre-separator suppressing the bouncing of particles on meshes. The separation performance of a triple-nozzle inertial filter was also discussed to investigate the influence of scale-up on the separation performance of a multi-nozzle inertial filter. The influence of particle loading on the pressure drop and separation performance was discussed. A supplemental inlet for the nano-particle collection applied to an existing portable high-volume air sampler was devised and the consistency with other types of existing samplers was discussed based on the sampling of ambient particles. The layered-mesh inertial filter with a webbed stainless steel fiber mat as a pre-separator showed good performance in the separation of particles with a d p50 ranging from 150 to 190 nm keeping the influence of loaded particles small. The developed layered-mesh inertial filter was successfully applied to the collection of particles at a d p50∼ 190 nm that was consistent with the results from existing samplers.

  2. 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

  3. 40 CFR 86.519-90 - Constant volume sampler calibration.

    Science.gov (United States)

    2010-07-01

    ... by EPA for both PDP (Positive Displacement Pump) and CFV (Critical Flow Venturi) are outlined below... establish the flow rate of the constant volume sampler pump. All the parameters related to the pump are simultaneously measured with the parameters related to a flowmeter which is connected in series with the...

  4. FIELD EVALUATION OF A HIGH-VOLUME DICHOTOMOUS SAMPLER

    Science.gov (United States)

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

  5. Research Note Difference between low-volume and high-volume Andersen samplers in measuring atmospheric aerosols

    Institute of Scientific and Technical Information of China (English)

    Fengfu Fu; Nobuo Shinohaya; Mitsuo Ito; Xueqin Xu; Mincong Shen; Liangjun Xu

    2008-01-01

    The mass concentration and size distribution of aerosols in Tokaimura were investigated using a high-volume and a low-volume Andersen sampler. A difference was found using the two samplers: the concentration of total aerosols determined with the high-volume sampler is smaller than that of the low-volume sampler by 70-90% throughout the year. Compared to the high-volume sampler, low-volume sampler gave lower concentration for aerosols7μm, higher concentration for aerosols of 3.3-7.0μm and<1.1μm, though similar results for aerosols of 1.1-3.3μm. The low-volume sampler was found to have better separation efficiency and higher accuracy.

  6. 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.

  7. Operating a High Volume Plankton Sampler from a Deep Water Autonomous Underwater Vehicle

    Science.gov (United States)

    Kaiser, C. L.; Billings, A.; Young, C.; Hiebert, L.; Van Dover, C. L.

    2016-02-01

    During the summer of 2015, a high volume plankton sampler was placed on the Autonomous Underwater Vehicle (AUV) Sentry as part of a cruise to investigate methane seeps. The sampler was successful in collecting over 800 larvae and 130 morphotypes. Most samples were split 2:1 or 4:1, so the total collection was substantially higher. The Sentry Precision Impeller Driven Sampler (SyPRID Sampler) was designed to mount as a "backpack" for the AUV Sentry. Sentry is able to fly the sampler at precision altitude as close as 150 cm from the seafloor and in precision patterns or locations for durations of 18 hours or more. Acoustic telemetry is used to monitor both Sentry and the samplers and to tune flight profiles or sampler operation in real time. Two independent samples can be collected per dive, allowing for comparative studies. The sampler is designed based on lessons learned from traditional tow-net systems and utilizes standard mesh net - in this case 150 micron. The sampler is impeller driven and Sentry moves at approximately 0.25m/s, resulting in little or no bow wave while maintaining an estimated flow rate of between 600 and 1000 m3/h per side. The sampler funnels plankton to a "cod end", where restriction and expansion is used to substantially reduce fluid pressure and velocity, thereby preserving the larvae in excellent condition. Valves are used to prevent contamination when not actively sampling. Substantial co-registered data is collected during the sampling including, CTD, optical backscatter, dissolved Oxygen, redox potential, and magnetics. When sampling more than 5m above bottom, multibeam sonar data can be collected. Future work will include simultaneous photography of the bottom for low-altitude sampling missions, real-time flow rate measurement, and simultaneous collection of ADCP water column data. Future work will also likely include use in the water column. The sampler is available for use on Sentry through UNOLS.

  8. 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

    2017-02-01

    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. In this paper, we will report the details of the sampling system of Hayabusa2 with results of performance tests during the development and the current status of the sampling system.

  9. 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.

  10. 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.

  11. 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...

  12. Determination of respirable mass concentration using a high volume air sampler and a sedimentation method for fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.

    1995-12-31

    A preliminary study of a new method for determining respirable mass concentration is described. This method uses a high volume air sampler and subsequent fractionation of the collected mass using a particle sedimentation technique. Side-by-side comparisons of this method with cyclones were made in the field and in the laboratory. There was good agreement among the samplers in the laboratory, but poor agreement in the field. The effect of wind on the samplers` capture efficiencies is the primary hypothesized source of error among the field results. The field test took place at the construction site of a hazardous waste landfill located on the Hanford Reservation.

  13. 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

    by the electrostatic field sampler and 11.8 mg m(-3) when measured by the GSP inhalable dust sampler. The quantity (amount per mg dust) of total fungi, Aspergillus fumigatus, total bacteria, endotoxin and mesophilic actinomycetes sampled by the electrostatic field samplers and the Gravikon samplers varied within...

  14. SyPRID sampler: A large-volume, high-resolution, autonomous, deep-ocean precision plankton sampling system

    Science.gov (United States)

    Billings, Andrew; Kaiser, Carl; Young, Craig M.; Hiebert, Laurel S.; Cole, Eli; Wagner, Jamie K. S.; Van Dover, Cindy Lee

    2017-03-01

    The current standard for large-volume (thousands of cubic meters) zooplankton sampling in the deep sea is the MOCNESS, a system of multiple opening-closing nets, typically lowered to within 50 m of the seabed and towed obliquely to the surface to obtain low-spatial-resolution samples that integrate across 10 s of meters of water depth. The SyPRID (Sentry Precision Robotic Impeller Driven) sampler is an innovative, deep-rated (6000 m) plankton sampler that partners with the Sentry Autonomous Underwater Vehicle (AUV) to obtain paired, large-volume plankton samples at specified depths and survey lines to within 1.5 m of the seabed and with simultaneous collection of sensor data. SyPRID uses a perforated Ultra-High-Molecular-Weight (UHMW) plastic tube to support a fine mesh net within an outer carbon composite tube (tube-within-a-tube design), with an axial flow pump located aft of the capture filter. The pump facilitates flow through the system and reduces or possibly eliminates the bow wave at the mouth opening. The cod end, a hollow truncated cone, is also made of UHMW plastic and includes a collection volume designed to provide an area where zooplankton can collect, out of the high flow region. SyPRID attaches as a saddle-pack to the Sentry vehicle. Sentry itself is configured with a flight control system that enables autonomous survey paths to low altitudes. In its verification deployment at the Blake Ridge Seep (2160 m) on the US Atlantic Margin, SyPRID was operated for 6 h at an altitude of 5 m. It recovered plankton samples, including delicate living larvae, from the near-bottom stratum that is seldom sampled by a typical MOCNESS tow. The prototype SyPRID and its next generations will enable studies of plankton or other particulate distributions associated with localized physico-chemical strata in the water column or above patchy habitats on the seafloor.

  15. 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.

  16. Comparison of annular diffusion denuder and high volume air samplers for measuring per- and polyfluoroalkyl substances in the atmosphere.

    Science.gov (United States)

    Ahrens, Lutz; Shoeib, Mahiba; Harner, Tom; Lane, Douglas A; Guo, Rui; Reiner, Eric J

    2011-12-15

    Overestimation of the particle phase concentration collected on glass-fiber filters (GFFs) has been reported for perfluoroalkyl carboxylic acids (PFCAs) using conventional high volume air samplers. In this study, per- and polyfluoroalkyl substances (PFASs) were determined in the gas and particulate phases using colocated annular diffusion denuder and high volume air samplers at a semiurban site in Toronto, Canada, in winter 2010. Samples were analyzed for 7 PFAS classes (i.e., PFCAs, perfluoro-alkane sulfonic acids (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer methacrylates (FTMACs), fluorotelomer acrylates (FTACs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamidoethanols (FOSEs)). The gas diffusion coefficients for individual PFASs were calculated and the denuder performance was evaluated. Modeled subcooled liquid vapor pressures (p(L)) correlated well with the vapor phase breakthrough for the denuder and high volume air systems. Total air concentrations for PFASs measured using annular diffusion denuders and high volume samplers were in agreement within a factor of 4; however, much greater differences were observed for measurements of gas-particle partitioning. Vapor phase PFSAs and PFCAs can adsorb to the GFF using high volume air samplers, resulting in much higher particle-associated fractions for these chemicals compared to the annular diffusion denuder sampler. This effect was not observed for the FTOHs, FTMACs, FTACs, FOSAs, and FOSEs. Thus, for investigations of gas-particle partitioning of PFSAs and PFCAs, the diffusion denuder sampler is the preferred method. The results of this study improve our understanding of the gas-particle partitioning of PFASs, which is important for modeling their long-range transport in air.

  17. Sampling small volumes of ambient ammonia using a miniaturized gas sampler.

    Science.gov (United States)

    Timmer, Björn; Olthuis, Wouter; van den Berg, Albert

    2004-06-01

    The development of a gas sampler for a miniaturized ambient ammonia detector is described. A micromachined channel system is realized in glass and silicon using powder blasting and anodic bonding. The analyte gas is directly mixed with purified water, dissolving the ammonia that will dissociate into ammonium ions. Carrier gas bubbles are subsequently removed from the liquid stream through a venting hole sealed with a microporous water repellent PTFE membrane. A flow restrictor is placed at the outlet of the sampler to create a small overpressure underneath the membrane, enabling the gas to leave through the membrane. Experiments with a gas flow of 1 ml min(-1), containing ammonia concentrations ranging from 9.4 ppm to 0.6 ppm in a nitrogen carrier flow have been carried out, at a water flow of 20 microl min(-1). The ammonium concentration in the sample solution is measured with an electrolyte conductivity detector. The measured values correspond with the concentration calculated from the initial ammonia concentration in the analyte gas, the fifty times concentration enhancement due to the gas-liquid volume difference and the theoretical dissociation equilibrium as a function of the resulting pH.

  18. Monitoring of air radioactivity at the Jungfraujoch research station: Test of a new high volume aerosol sampler

    OpenAIRE

    Flury, Thomas; Völkle, Hansruedi

    2008-01-01

    The Swiss Federal Office of Public Health (SFOPH) is responsible for the surveillance of environmental radioactivity in Switzerland and for the protection of the public from ionizing and non-ionizing radiation. In order to improve the Swiss radioactivity monitoring network, a new high volume air sampler (DIGITEL DHA-80) was tested in Fribourg and at the Jungfraujoch High Altitude Research Station at 3454 m. The filters are analyzed in the laboratory by a high purity coaxial germanium detector...

  19. Quartz in coal dust deposited on internal surface of respirable size selective samplers.

    Science.gov (United States)

    Soo, Jhy-Charm; Lee, Taekhee; Kashon, Michael; Kusti, Mohannad; Harper, Martin

    2014-01-01

    The objective of the present study is to quantify quartz mass in coal dust deposited on the internal cassette surface of respirable size-selective samplers. Coal dust was collected with four different respirable size-selective samplers (10 mm Dorr-Oliver nylon [Sensidyne, St. Petersburg, Fla.], SKC Aluminum [SKC Inc., Eighty Four, Pa.], BGI4L [BGI USA Inc., Waltham, Mass.], and GK2.69 cyclones [BGI USA Inc.]) with two different cassette types (polystyrene and static-dissipative polypropylene cassettes). The coal dust was aerosolized in a calm air chamber by using a fluidized bed aerosol generator without neutralization under the assumption that the procedure is similar to field sampling conditions. The mass of coal dust was measured gravimetrically and quartz mass was determined by Fourier transform infrared spectroscopy according to the National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods, Method 7603. The mass fractions of the total quartz sample on the internal cassette surface are significantly different between polystyrene and static-dissipative cassettes for all cyclones (p quartz mass on cassette internal surface and coal dust filter mass was observed. The BGI4L cyclone showed a higher (but not significantly) and the GK2.69 cyclone showed a significantly lower (p quartz mass fraction for polystyrene cassettes compared to other cyclones. This study confirms previous observations that the interior surface deposits in polystyrene cassettes attached to cyclone pre-selectors can be a substantial part of the sample, and therefore need to be included in any analysis for accurate exposure assessment. On the other hand, the research presented here supports the position that the internal surface deposits in static-dissipative cassettes used with size-selective cyclones are negligible and that it is only necessary to analyze the filter catch.

  20. Sampling small volumes of ambient ammonia using a miniaturized gas sampler

    NARCIS (Netherlands)

    Timmer, B.H.; Olthuis, Wouter; van den Berg, Albert

    2004-01-01

    The development of a gas sampler for a miniaturized ambient ammonia detector is described. A micromachined channel system is realized in glass and silicon using powder blasting and anodic bonding. The analyte gas is directly mixed with purified water, dissolving the ammonia that will dissociate into

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

    Science.gov (United States)

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

    2006-09-01

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

  2. Immunochemical estimations of allergenic activities from outdoor aero-allergens, collected by a high-volume air sampler

    DEFF Research Database (Denmark)

    Jensen, J; Poulsen, L K; Mygind, K;

    1989-01-01

    To quantify airborne allergens in amorphus and morphological particles, a survey with collection of aero-allergens on glass fibre filters by means of a high-volume air-sampler (HIVOL) was conducted. In preliminary laboratory experiments we compared various filter elution techniques......, and the pulverizing elution technique was found to be optimal with regard to yield and convenience. When a surfactant, Tween 20 (0.5% v/v), was added to the elution buffer, a recovery of 80% could be obtained. Allergens in eluates were analysed by means of an IgG-subclass RAST inhibition assay. This immunochemical...... method for quantification of airborne allergens was validated, as a high recovery of timothy grass pollen allergens was eluted from air filters, and eluates were shown specific by RAST inhibition. The amount of immunochemically measured airborne timothy and birch allergens collected by means of the HIVOL...

  3. Monitoring of 45 pesticides in Lebanese surface water using polar organic chemical integrative sampler (POCIS)

    Science.gov (United States)

    Aisha, Al Ashi; Hneine, Wael; Mokh, Samia; Devier, Marie-Hélène; Budzinski, Hélèn; Jaber, Farouk

    2017-07-01

    The aim of this study is to assess the dissolved concentration of 45 pesticides in the surface waters of the Lebanese Republic using Polar Organic Chemical Integrative Sampler "POCIS". All of the sampling sites are located in the major agricultural land areas in Lebanon. POCIS (n = 3) were deployed at Ibrahim River, Qaraoun Lake and Hasbani River for a duration of 14 days. The total concentration of pesticides ranged from not detected (nd) to 137.66 ng.L-1. Chlorpyrifos, DDE-pp, diazinon and Fenpropathrin were the most abundant compounds. Qaraoun Lake and Hasbani River were found to be more polluted than Ibrahim River, since they receive large amounts of waste water derived from nearby agricultural lands and they had the lowest dilution factor. The aqueous average concentration of the target compounds were estimated using sampling rates obtained from the literature. Comparison between Time Weighed Average concentrations "TWA" using POCIS and spot sampling is presented. Results showed that POCIS TWA concentrations are in agreement with spot sampling concentrations for Ibrahim and Hasbani Rivers. The toxicity of the major detected pesticides on three representative aquatic species (Daphnia magna, Scenedesmus quadricauda and Oncorhynchus mykiss) is also reported.

  4. High volume air sampler for environmental nanoparticles using a sharp-cut inertial filter combined with an impactor

    Science.gov (United States)

    Zhang, Tong; Zhao, Tianren; Takahashi, Hideaki; Hata, Mitsuhiko; Toriba, Akira; Ikeda, Takuji; Otani, Yoshio; Furuuchi, Masami

    2017-02-01

    A multi-nozzle layered mesh inertial filter, developed by the authors based on inertial filter technology for separating ultrafine particles (UFPs) at a moderate pressure drop, was investigated in an attempt to improve the steepness of the separation efficiency curve by combining an inertial filter and an impactor. In this system, the separation curves overlap each other, while maintaining about a 100 nm difference in cutoff size d p50. Such a combination, which we refer to as a ‘hybrid inertial filter’, was validated for a single nozzle geometry. Using a multi nozzle geometry, it was scaled up to a high volume air sampling flow rate of 400 l min-1 at a pressure drop of  filter using multi-nozzle geometry was confirmed. The features of the hybrid inertial filter included the suppression of the bouncing of particles with sizes  >300 nm, a steeper collection efficiency curve and less pressure drop than those of a previous type of inertial filter. The ambient PM0.13 evaluated for the present unit was found to be in good agreement with values obtained for 2 different types of cascade air samplers.

  5. ROSS: The Remotely-Operated Surface Sampler - A MediumEndurance, Precision-Navigated Platform Optimized for Uncontaminated Measurement of Upper-Ocean Velocity, Density and Turbulence

    Science.gov (United States)

    2015-09-30

    ROSS : The Remotely-­‐Operated Surface Sampler A medium-­‐endurance, precision-­‐navigated  platform optimized...coas.oregonstate.edu Award N00014-­‐14-­‐1-­‐0490 http://kai.coas.oregonstate.edu/ OVERVIEW The Remotely Operated Surface   Sampler ( ROSS )  is an  open...configuration,   ROSS cruises at 4 knots,  is equipped  with  300 kHz  and 2 MHz  ADCPs,  and tows a 20-­‐m  lon thermistor/CTD  chain. Its

  6. Volume-Enclosing Surface Extraction

    CERN Document Server

    Schlei, B R

    2010-01-01

    A new method is presented here, which allows one to construct triangular surfaces from three-dimensional data sets, such as 3D image data and/or numerical simulation data that are based on regularly shaped, cubic lattices. This novel volume-enclosing surface extraction technique, which has been named VESTA, is guaranteed to always produce surfaces that do not contain any holes, e.g., in contrast to the well-known and very popular Marching Cubes algorithm, which has been developed by W.E. Lorensen and H.E. Cline in the mid-1980s. VESTA is not template based. In fact, the surface tiles are determined with a fast and robust construction technique. Among other things, VESTA's relationship to the DICONEX algorithm is explained, which -- in a lower-dimensional analogy -- produces contours from two-dimensional data sets, such as 2D gray-level images. In particular, the generation of isosurfaces from initially created VESTA surfaces is demonstrated here for the very first time. A few examples are provided, namely in ...

  7. Real-time detection of focal position of workpiece surface during laser processing using diffractive beam samplers

    Science.gov (United States)

    Cao, Binh Xuan; Hoang, PhuongLe; Ahn, Sanghoon; Kim, Jeng-o.; Sohn, Hyonkee; Noh, Jiwhan

    2016-11-01

    The real-time fabrication of microgrooves on a curved surface using a laser beam, without preprogramming their shapes into the machining instructions, is a major challenge in laser processing owing to limitations associated with the real-time detection of the focal position. A new approach using a sampled fraction of the beam from a diffractive beam sampler (DBS) is therefore presented in order to overcome this limitation. By considering the sampled fraction of the beam an analysis of the results allows for precise positioning of the specimen for focal-point identification. This allows for the determination of the focus for a broad variety of laser types and laser powers, thereby providing stringent focusing conditions with high numerical apertures. This approach is easy to implement, inexpensive, independent of the roughness or granularity of the workpieces, and more importantly does not require auxiliary lasers and displacement sensors for real-time measurement during the fabrication process.

  8. Volume and Surface-Enhanced Volume Negative Ion Sources

    CERN Document Server

    Stockli, M P

    2013-01-01

    H- volume sources and, especially, caesiated H- volume sources are important ion sources for generating high-intensity proton beams, which then in turn generate large quantities of other particles. This chapter discusses the physics and technology of the volume production and the caesium-enhanced (surface) production of H- ions. Starting with Bacal's discovery of the H- volume production, the chapter briefly recounts the development of some H- sources, which capitalized on this process to significantly increase the production of H- beams. Another significant increase was achieved in the 1990s by adding caesiated surfaces to supplement the volume-produced ions with surface-produced ions, as illustrated with other H- sources. Finally, the focus turns to some of the experience gained when such a source was successfully ramped up in H- output and in duty factor to support the generation of 1 MW proton beams for the Spallation Neutron Source.

  9. Evaluating and modeling the effects of surface sampling factors on the recovery of organic chemical attribution signatures using the accelerated diffusion sampler and solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Kai-For; Heredia-Langner, Alejandro; Fraga, Carlos G.

    2017-03-01

    In this study, an experimental design matrix was created and executed in order to test the effects of various real-world factors on the ability of the (1) accelerated diffusion sampler with solid phase micro-extraction (ADS-SPME) and (2) solvent extraction to capture organic chemical attribution signatures (CAS) from dimethyl methylphosphonate (DMMP) spiked onto painted wall board (PWB) surfaces. The DMMP CAS organic impurities sampled by ADS-SPME and solvent extraction were analyzed by gas chromatography/mass spectrometry (GC/MS). The number of detected DMMP CAS impurities and their respective GC/MS peak areas were determined as a function of DMMP stock, DMMP spiked volume, exposure time, SPME sampling time, and ADS headspace pressure. Based on the statistical analysis of experimental results, several general conclusions are made: (1) ADS-SPME with vacuum (i.e., reduced pressure) increased the amount of detected CAS impurity, as measured by GC/MS peak area, by a factor of 1.7 to 1.9 for PWB under certain experimental conditions, (2) the amount of detected CAS impurity was most influenced by spiked volume, stock, and ADS headspace pressure, (3) the ADS had no measurable effect on the number of detected DMMP impurities, that is, the ADS (with and without reduced pressure) had no practical effect on the DMMP impurity profile collected from spiked PWB, and (4) solvent extraction out performed ADS-SPME in terms of consistently capturing all or most of the targeted DMMP impurities from spiked PWB.

  10. Evaluating and modeling the effects of surface sampling factors on the recovery of organic chemical attribution signatures using the accelerated diffusion sampler and solvent extraction.

    Science.gov (United States)

    Mo, Kai-For; Heredia-Langner, Alejandro; Fraga, Carlos G

    2017-03-01

    In this study, an experimental design matrix was created and executed to test the effects of various real-world factors on the ability of (1) the accelerated diffusion sampler with solid phase micro-extraction (ADS-SPME) and (2) solvent extraction to capture organic chemical attribution signatures (CAS) from dimethyl methylphosphonate (DMMP) spiked onto painted wall board (PWB) surfaces. The DMMP CAS organic impurities sampled by ADS-SPME and solvent extraction were analyzed by gas chromatography/mass spectrometry (GC/MS). The number of detected DMMP CAS impurities and their respective GC/MS peak areas were determined as a function of DMMP stock, DMMP spiked volume, exposure time, SPME sampling time, and ADS headspace pressure. Based on the statistical analysis of experimental results, several general conclusions are made: (1) the amount of CAS impurity detected using ADS-SPME and GC/MS was most influenced by spiked volume, stock, and ADS headspace pressure, (2) reduced ADS headspace pressure increased the amount of detected CAS impurity, as measured by GC/MS peak area, by up to a factor of 1.7-1.9 compared to ADS at ambient headspace pressure, (3) the ADS had no measurable effect on the number of detected DMMP impurities, that is, ADS (with and without reduced pressure) had no practical effect on the DMMP impurity profile collected from spiked PWB, and (4) solvent extraction out performed ADS-SPME in terms of consistently capturing all or most of the targeted DMMP impurities from spiked PWB.

  11. Evaluating the polar organic chemical integrative sampler for the monitoring of beta-blockers and hormones in wastewater treatment plant effluents and receiving surface waters.

    Science.gov (United States)

    Jacquet, Romain; Miège, Cécile; Bados, Philippe; Schiavone, Séverine; Coquery, Marina

    2012-02-01

    Wastewater treatment plants (WWTP) are known to be a source of surface water contamination by organic compounds such as pharmaceuticals. The objective of the present work was to study the suitability of the polar organic chemical integrative sampler (POCIS) to monitor beta-blockers and hormones in effluents and surface waters. Four sampling campaigns were carried out in French rivers (the Saône, the Ardières, the Bourbre, and the Seine) between November 2007 and September 2008. Passive samplers were exposed in surface waters, upstream and downstream of WWTP outflows, and in effluents. Exposures lasted for up to 24 d to study the uptake kinetics directly in situ, and repeatability was assessed by exposure of triplicates. A good agreement was found between POCIS and water samples. With the exception of atenolol, beta-blockers showed a linear uptake during at least three weeks, and their sampling rates could be determined in situ. These sampling rates were then used to calculate time-weighted average concentrations of beta-blockers in the Seine River with an overall good accuracy and repeatability. Such calculations could not be performed for hormones because of their variable occurrences and low concentrations in water and POCIS. Polar organic chemical integrative sampler therefore seems to be a suitable tool for monitoring beta-blockers in surface waters impacted by WWTP effluents. Longer exposure durations would be necessary to determine the suitability of POCIS for monitoring hormones. Finally, preliminary assays on the use of several deuterated compounds as performance reference compounds showed promising results for deuterated atenolol. Copyright © 2011 SETAC.

  12. Polar organic chemical integrative sampler (POCIS): application for monitoring organic micropollutants in wastewater effluent and surface water

    OpenAIRE

    Miège, C.; Budzinski, H.; Jacquet, R.; Soulier, C.; Pelte, T.; Coquery, M.

    2012-01-01

    In this paper, we discuss the advantages and drawbacks of POCIS (Polar Organic Chemical Integrative Sampler) for the evaluation of river water quality downstream of wastewater treatment plants. POCIS proved well adapted to sampling alkylphenols and several pharmaceuticals. Concentration factors and the decrease in limits of quantification, compared to grab water sample analyses, were significant except for hormones, β-blockers and bronchodilators. Promising preliminary results obtained i...

  13. Osmosis and Surface Area to Volume Ratio.

    Science.gov (United States)

    Barrett, D. R. B.

    1984-01-01

    Describes an experiment designed to help students understand the concepts of osmosis and surface area to volume ratio (SA:VOL). The task for students is to compare water uptake in different sizes of potato cubes and relate differences to their SA:VOL ratios. (JN)

  14. Surface and Volume Grid Generation in Parametric Form

    Science.gov (United States)

    Yu, Tzuyi; Soni, Bharat K.; Benjamin, Ted; Williams, Robert

    1996-01-01

    The algorithm for surface modeling and volume grid generation using parametric Non-Uniform Rational B-splines (NURBS) geometric representation are presented. The enhanced re-parameterization algorithm which can yield a desired physical distribution on the curve, surface, and volume is also presented. This approach bridges the gap between computer aided design surface/volume definition and surface/volume grid generation.

  15. Volumes and surface areas of pendular rings

    Science.gov (United States)

    Rose, W.

    1958-01-01

    A packing of spheres is taken as a suitable model of porous media. The packing may be regular and the sphere size may be uniform, but in general, both should be random. Approximations are developed to give the volumes and surface areas of pendular rings that exist at points of sphere contact. From these, the total free volume and interfacial specific surface area are derived as expressive of the textural character of the packing. It was found that the log-log plot of volumes and surface areas of pendular rings vary linearly with the angle made by the line joining the sphere centers and the line from the center of the largest sphere to the closest edge of the pendular ring. The relationship, moreover, was found not to be very sensitive to variation in the size ratio of the spheres in contact. It also was found that the addition of pendular ring material to various sphere packings results in an unexpected decrease in the surface area of the boundaries that confine the resulting pore space. ?? 1958 The American Institute of Physics.

  16. Polar organic chemical integrative sampler (POCIS): application for monitoring organic micropollutants in wastewater effluent and surface water.

    Science.gov (United States)

    Miège, Cécile; Budzinski, Hélène; Jacquet, Romain; Soulier, Coralie; Pelte, Thomas; Coquery, Marina

    2012-02-01

    In this paper, we discuss the advantages and drawbacks of POCIS (Polar Organic Chemical Integrative Sampler) for the evaluation of river water quality downstream of wastewater treatment plants. POCIS proved well adapted to sampling alkylphenols and several pharmaceuticals. Concentration factors and the decrease in limits of quantification, compared to grab water sample analyses, were significant except for hormones, β-blockers and bronchodilators. Promising preliminary results obtained in situ on deuterated atenolol used as a performance reference compound need to be confirmed in-lab. This work confirms that POCIS is a valuable tool for monitoring hydrophilic organic molecules in river and wastewaters.

  17. Volume versus surface nucleation in freezing aerosols

    Science.gov (United States)

    Sigurbjörnsson, Ómar F.; Signorell, Ruth

    2008-05-01

    The present study puts an end to the ongoing controversy regarding volume versus surface nucleation in freezing aerosols: Our study on nanosized aerosol particles demonstrates that current state of the art measurements of droplet ensembles cannot distinguish between the two mechanisms. The reasons are inherent experimental uncertainties as well as approximations used to analyze the kinetics. The combination of both can lead to uncertainties in the rate constants of two orders of magnitude, with important consequences for the modeling of atmospheric processes.

  18. A multipoint (49 points) study of dry deposition of polycyclic aromatic hydrocarbons (PAHs) in Erzurum, Turkey by using surrogated snow surface samplers.

    Science.gov (United States)

    Bayraktar, Hanefi; Paloluoğlu, Cihan; Turalioğlu, Fatma S; Gaga, Eftade O

    2016-06-01

    Dry deposition of atmospheric 18 polycyclic aromatic hydrocarbon (PAH) components was investigated in the scope of the study by using surrogate snow samplers at 49 different sampling points in and around the city center of Erzurum, Turkey. Snow was sampled twice, the first of which was taken immediately after the first fresh snow cover and placed into aluminum trays to obtain dry deposition surface while the second sample was taken from the snow cover (accumulated snow) exposed to an 8-day dry deposition period and then analyzed and extracted. All the samples taken from the samplers were extracted using solid and liquid phase extraction and analyzed through GC-MS. It was observed that at the end of an 8-day dry period, snow samples enriched 5.5 times more in PAH components than the baseline. PAH deposition was determined to be influenced mainly by coal, mixed source, traffic, diesel fuel, and petrol fuel at 43, 27, 20, 8, and 2 % of sampling points, respectively. Local polluting sources were found to be effective on the spatial distribution of dry deposition of PAH components in urban area.

  19. Solid sorbent air sampler

    Science.gov (United States)

    Galen, T. J.

    1986-04-01

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

  20. Direct gravimetric measurements of the mass of the antarctic aerosol collected by high volume sampler: PM10 summer seasonal variation at Terra Nova Bay.

    Science.gov (United States)

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

    2005-01-01

    An on-site procedure was set up for direct gravimetric measurement of the mass of aerosol collected using high volume impactors (aerodynamic size cut point of 10 microm, PM10); this knowledge has hitherto been unavailable. Using a computerized microbalance in a clean chemistry laboratory, under controlled temperature (+/-0.5 degrees C) and relative humidity (+/-1%), continuous, long time filter mass measurements (hours) were carried out before and after exposure, after a 48 h minimun equilibration at the laboratory conditions. The effect of the electrostatic charge was exhausted in 30-60 min, after which stable measurements were obtained. Measurements of filters exposed for 7-11 days (1.13 m3 min(-1)) in a coastal site near Terra Nova Bay (December 2000 - February 2001), gave results for aerosol mass in the order of 10-20 mg (SD approximately 2 mg), corresponding to atmospheric concentrations of 0.52-1.27 microg m(-3). Data show a seasonal behaviour in the PM10 content with an increase during December - early January, followed by a net decrease. The above results compare well with estimates obtained from proxy data for the Antarctic Peninsula (0.30 microg m(-3)), the Ronne Ice Shelf (1.49 microg m(-3)), and the South Pole (0.18 microg m(-3), summer 1974-1975, and 0.37 microg m(-3), average summer seasons 1975-1976 and 1977-1978), and from direct gravimetric measurements recently obtained from medium volume samplers at McMurdo station (downwind 3.39 microg m(-3), upwind 4.15 microg m(-3)) and at King George Island (2.5 microg m(-3), summer, particle diameter <20 microm). This finding opens the way to the direct measurement of the chemical composition of the Antarctic aerosol and, in turn, to a better knowledge of the snow/air relationships as required for the reconstruction of the chemical composition of past atmospheres from deep ice core data.

  1. Uranium in US surface, ground, and domestic waters. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

    1981-04-01

    The report Uranium in US Surface, Ground, and Domestic Waters comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium conentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

  2. Surface and volume photoemission of hot electrons from plasmonic nanoantennas

    DEFF Research Database (Denmark)

    Uskov, Alexander V.; Protsenko, Igor E.; Ikhsanov, Renat S.;

    2014-01-01

    We theoretically compare surface- and volume-based photoelectron emission from spherical nanoparticles, obtaining analytical expressions for the emission rate in both mechanisms. We show that the surface mechanism prevails, being unaffected by detrimental hot electron collisions....

  3. Surface and volume photoemission of hot electrons from plasmonic nanoantennas

    DEFF Research Database (Denmark)

    Uskov, Alexander V.; Protsenko, Igor E.; Ikhsanov, Renat S.

    2014-01-01

    We theoretically compare surface- and volume-based photoelectron emission from spherical nanoparticles, obtaining analytical expressions for the emission rate in both mechanisms. We show that the surface mechanism prevails, being unaffected by detrimental hot electron collisions.......We theoretically compare surface- and volume-based photoelectron emission from spherical nanoparticles, obtaining analytical expressions for the emission rate in both mechanisms. We show that the surface mechanism prevails, being unaffected by detrimental hot electron collisions....

  4. Vibration Adaptive Control of the Flexible Lunar Regolith Sampler

    Directory of Open Access Journals (Sweden)

    Bao-guo XU

    2012-12-01

    Full Text Available With respect to the problem of big volume, large weight and high power consumption of lunar sampler nowadays, the paper firstly described a novel flexible mini lunar regolith sampler. Then the vibration model of it is established while drilling. The drilling efficiency can be improved more effectively by controlling the lunar regolith sampler always in the resonance state. But the dynamical modeling of the sampler-regolith system is difficult to obtain and time varies when the sampler is in different depth in the lunar regolith. So we present a method of the vibration frequency fuzzy adaptive control based on the dynamic prediction by using the Levenberg-Marquardt Back Propagation (LMBP neural networks. The LMBP with a FIR filter in series is used to predict the resonant frequency dynamically. And the fuzzy adaptive control is used to calculate the sweeping frequency bandwidth with the input of the amplitude and variation. The simul

  5. Influence of Geometry on a High Surface Area-Solid Phase Microextraction Sampler for Chemical Vapor Collection

    Science.gov (United States)

    2007-06-04

    Flow Microfiltration ." Journal of Membrane Science 102(1-3): 31-42. 62 Hook, G. L., C. Jackson Lepage, et al. (2004). "Dynamic solid phase...Xia 2001) In another experiment, 1cm x 1cm and 1cm x 2cm sheets of thin PDMS membrane , with surface areas ~20 and ~40 times greater than a 100 μm...PDMS coated SPME fiber. The membranes were attached to a thin, deactivated stainless steel rod, in a configuration similar to a flag on a flagpole

  6. Condylar volume and surface in Caucasian young adult subjects

    OpenAIRE

    Cordasco Giancarlo; Pagnoni Mario; Polimeni Antonella; Nucera Riccardo; Saccucci Matteo; Tecco Simona; Festa Felice; Iannetti Giorgio

    2010-01-01

    Abstract Background There have been no quantitative standards for volumetric and surface measurements of the mandibular condyle in Caucasian population. However, the recently developed cone-beam computed tomography (CBCT) system allows measurement of these parameters with high accuracy. Methods CBCT was used to measure the condylar volume, surface and the volume to surface ratio, called the Morphometric Index (MI), of 300 temporo-mandibular joints (TMJ) in 150 Caucasian young adult subjects, ...

  7. Environmental Awareness Sampler.

    Science.gov (United States)

    Halnen, Andrew; And Others

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

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

    Science.gov (United States)

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

    2016-10-01

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

  9. 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.

  10. Active Sampling Device for Determining Pollutants in Surface and Pore Water - the In Situ Sampler for Biphasic Water Monitoring

    Science.gov (United States)

    Supowit, Samuel D.; Roll, Isaac B.; Dang, Viet D.; Kroll, Kevin J.; Denslow, Nancy D.; Halden, Rolf U.

    2016-02-01

    We designed and evaluated an active sampling device, using as analytical targets a family of pesticides purported to contribute to honeybee colony collapse disorder. Simultaneous sampling of bulk water and pore water was accomplished using a low-flow, multi-channel pump to deliver water to an array of solid-phase extraction cartridges. Analytes were separated using either liquid or gas chromatography, and analysis was performed using tandem mass spectrometry (MS/MS). Achieved recoveries of fipronil and degradates in water spiked to nominal concentrations of 0.1, 1, and 10 ng/L ranged from 77 ± 12 to 110 ± 18%. Method detection limits (MDLs) were as low as 0.040-0.8 ng/L. Extraction and quantitation of total fiproles at a wastewater-receiving wetland yielded concentrations in surface water and pore water ranging from 9.9 ± 4.6 to 18.1 ± 4.6 ng/L and 9.1 ± 3.0 to 12.6 ± 2.1 ng/L, respectively. Detected concentrations were statistically indistinguishable from those determined by conventional, more laborious techniques (p > 0.2 for the three most abundant fiproles). Aside from offering time-averaged sampling capabilities for two phases simultaneously with picogram-per-liter MDLs, the novel methodology eliminates the need for water and sediment transport via in situ solid phase extraction.

  11. Arc Length Based Grid Distribution For Surface and Volume Grids

    Science.gov (United States)

    Mastin, C. Wayne

    1996-01-01

    Techniques are presented for distributing grid points on parametric surfaces and in volumes according to a specified distribution of arc length. Interpolation techniques are introduced which permit a given distribution of grid points on the edges of a three-dimensional grid block to be propagated through the surface and volume grids. Examples demonstrate how these methods can be used to improve the quality of grids generated by transfinite interpolation.

  12. Arc length based grid distribution for surface and volume grids

    Energy Technology Data Exchange (ETDEWEB)

    Mastin, C.W. [NASA Langley Research Center, Hampton, VA (United States)

    1996-12-31

    Techniques are presented for distributing grid points on parametric surfaces and in volumes according to a specified distribution of arc length. Interpolation techniques are introduced which permit a given distribution of grid points on the edges of a three-dimensional grid block to be propagated through the surface and volume grids. Examples demonstrate how these methods can be used to improve the quality of grids generated by transfinite interpolation.

  13. A volume-based method for denoising on curved surfaces

    KAUST Repository

    Biddle, Harry

    2013-09-01

    We demonstrate a method for removing noise from images or other data on curved surfaces. Our approach relies on in-surface diffusion: we formulate both the Gaussian diffusion and Perona-Malik edge-preserving diffusion equations in a surface-intrinsic way. Using the Closest Point Method, a recent technique for solving partial differential equations (PDEs) on general surfaces, we obtain a very simple algorithm where we merely alternate a time step of the usual Gaussian diffusion (and similarly Perona-Malik) in a small 3D volume containing the surface with an interpolation step. The method uses a closest point function to represent the underlying surface and can treat very general surfaces. Experimental results include image filtering on smooth surfaces, open surfaces, and general triangulated surfaces. © 2013 IEEE.

  14. Embedded active surfaces for volume visualization

    Science.gov (United States)

    Whitaker, Ross T.; Chen, David

    1994-05-01

    We propose a new technique for use in the visualization of sparse, fuzzy, or noisy 3D data. This technique incorporates the methods of deformable or active models that have been developed in 2D computer vision. In this paper we generalize such models to 3D in a manner that is both practical and mathematically elegant, and we thereby avoid many of the problems associated with previous attempts to generalize deformable models. When generalizing to 3D, deformable models have several drawbacks-- including their acute sensitivity to topology, parameterization, and initial conditions--which limit their effectiveness. Many of these problems stem from the underlying parameterization of the model. This paper presents an implicit representation of deformable models. The implicit representation is an embedding of objects as level sets of grayscale functions which serve as templates. The evolution equation associated with the energy minimization process for a model has an analogous partial differential equation which governs the behavior of the corresponding grayscale template. We show that the 'active blobs' associated with the embedding of active models have several useful properties. First, they are topologically flexible. Second, grayscale images represent families of models. Third, when surfaces are embedded as grayscale images, they are described by a natural scale space. This scale space provides the ability to solve these equations in a multi-scale manner. Several 2D examples of technique are presented, as well as some visualization results from 3D ultrasound.

  15. 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)

  16. Direct Multifield Volume Ray Casting of Fiber Surfaces.

    Science.gov (United States)

    Wu, Kui; Knoll, Aaron; Isaac, Benjamin J; Carr, Hamish; Pascucci, Valerio

    2017-01-01

    Multifield data are common in visualization. However, reducing these data to comprehensible geometry is a challenging problem. Fiber surfaces, an analogy of isosurfaces to bivariate volume data, are a promising new mechanism for understanding multifield volumes. In this work, we explore direct ray casting of fiber surfaces from volume data without any explicit geometry extraction. We sample directly along rays in domain space, and perform geometric tests in range space where fibers are defined, using a signed distance field derived from the control polygons. Our method requires little preprocess, and enables real-time exploration of data, dynamic modification and pixel-exact rendering of fiber surfaces, and support for higher-order interpolation in domain space. We demonstrate this approach on several bivariate datasets, including analysis of multi-field combustion data.

  17. An operator calculus for surface and volume modeling

    Science.gov (United States)

    Gordon, W. J.

    1984-01-01

    The mathematical techniques which form the foundation for most of the surface and volume modeling techniques used in practice are briefly described. An outline of what may be termed an operator calculus for the approximation and interpolation of functions of more than one independent variable is presented. By considering the linear operators associated with bivariate and multivariate interpolation/approximation schemes, it is shown how they can be compounded by operator multiplication and Boolean addition to obtain a distributive lattice of approximation operators. It is then demonstrated via specific examples how this operator calculus leads to practical techniques for sculptured surface and volume modeling.

  18. Infinite volume of noncommutative black hole wrapped by finite surface

    Science.gov (United States)

    Zhang, Baocheng; You, Li

    2017-02-01

    The volume of a black hole under noncommutative spacetime background is found to be infinite, in contradiction with the surface area of a black hole, or its Bekenstein-Hawking (BH) entropy, which is well-known to be finite. Our result rules out the possibility of interpreting the entropy of a black hole by counting the number of modes wrapped inside its surface if the final evaporation stage can be properly treated. It implies the statistical interpretation for the BH entropy can be independent of the volume, provided spacetime is noncommutative. The effect of radiation back reaction is found to be small and doesn't influence the above conclusion.

  19. Lagrangian Transport Through Surfaces in Volume-Preserving Flows

    CERN Document Server

    Karrasch, Daniel

    2015-01-01

    Advective transport of scalar quantities through surfaces is of fundamental importance in many scientific applications. From the Eulerian perspective of the surface it can be quantified by the well-known integral of the flux density. The recent development of highly accurate semi-Lagrangian methods for solving scalar conservation laws and of Lagrangian approaches to coherent structures in turbulent (geophysical) fluid flows necessitate a new approach to transport from the (Lagrangian) material perspective. We present a Lagrangian framework for calculating transport of conserved quantities through a given surface in $n$-dimensional, fully aperiodic, volume-preserving flows. Our approach does not involve any dynamical assumptions on the surface or its boundary.

  20. Field intercomparison of ammonia passive samplers: results and lessons learned.

    Science.gov (United States)

    Stephens, Amy; Leeson, Sarah; Jones, Matthew; van Dijk, Netty; Kentisbeer, John; Twigg, Marsailidh; Simmons, Ivan; Braban, Christine; Martin, Nick; Poskitt, Janet; Ferm, Martin; Seitler, Eva; Sacco, Paolo; Gates, Linda; Stolk, Ariën; Stoll, Jean-Marc; Tang, Sim

    2017-04-01

    Ammonia pollution contributes significantly to eutrophication and acidification of ecosystems with resultant losses of biodiversity and ecosystem changes. Monitoring of ambient ammonia over a wide spatial and long temporal scales is primarily done with low-cost diffusive samplers. Less frequently, surface flux measurements of ammonia can be made using passive samplers at plot scale. This paper will present a field intercomparison conducted within the MetNH3 project to assess the performance of passive samplers for ambient measurements of ammonia. Eight different designs of commercial passive samplers housed in shelters provided by the manufacturer/laboratory were exposed over an 8-week period at the Whim experimental field site in Scotland between August and October 2016. Whim Bog has a facility in place for controlled releases of ammonia (http://www.whimbog.ceh.ac.uk/). Automated conditional release from the line source occurs when the wind direction in the preceding minute is from the northeast (wind sector 180-215°) and wind speed is > 5 m s-1. The passive samplers were exposed at different distances from the release source (16, 32 and 60 m) and also at a background location. Most were exposed for 2 x 4-week long periods and some for 4 x 2-week long periods. At the 32 m position, an active denuder method, the CEH DELTA sampler and a continuous high temporal resolution wet chemistry ammonia instrument (AiRRmonia, Mechatronics, NL.) were also deployed alongside the passive samplers to provide reference measurements of ammonia. Results are presented within the context of the MetNH3 CATFAC controlled laboratory exposure assessments. The results are discussed in terms of typical deployments of passive samplers and quality control. Measurement for policy evidence for both local and regional studies using passive samplers are discussed.

  1. Parallel optical sampler

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-20

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

  2. Condylar volume and surface in Caucasian young adult subjects

    Directory of Open Access Journals (Sweden)

    Cordasco Giancarlo

    2010-12-01

    Full Text Available Abstract Background There have been no quantitative standards for volumetric and surface measurements of the mandibular condyle in Caucasian population. However, the recently developed cone-beam computed tomography (CBCT system allows measurement of these parameters with high accuracy. Methods CBCT was used to measure the condylar volume, surface and the volume to surface ratio, called the Morphometric Index (MI, of 300 temporo-mandibular joints (TMJ in 150 Caucasian young adult subjects, with varied malocclusions, without pain or dysfunction of TMJs. Results The condylar volume was 691.26 ± 54.52 mm3 in males and 669.65 ± 58.80 mm3 in, and was significantly higher (p2 in males and 394.77 ± 60.73 mm2 in females. Furthermore, the condylar volume (693.61 ± 62.82 mm3 in the right TMJ was significantly higher than in the left (666.99 ± 48.67 mm3, p 2 in the right TMJ and 389.41 ± 56.63 mm2 in the left TMJ; t = 3.29; p Conclusion These data from temporomandibular joints of patients without pain or clinical dysfunction might serve as examples of normal TMJ's in the general population not seeking orthodontic care.

  3. Efficient volume preserving approach for skeleton-based implicit surfaces

    Institute of Scientific and Technical Information of China (English)

    史红兵; 童若锋; 董金祥

    2003-01-01

    This paper presents an efficient way to preserve the volume of implicit surfaces generated by skeletons. Recursive subdivision is used to efficiently calculate the volume. The criterion for subdivision is obtained by using the property of density functions and treating different types of skeletons respectively to get accurate minimum and maximum distances from a cube to a skeleton. Compared with the criterion generated by other ways such as using traditional Interval Analysis, Affine Arithmetic, or Lipschitz condition, our approach is much better both in speed and accuracy.

  4. Exact solutions to model surface and volume charge distributions

    Science.gov (United States)

    Mukhopadhyay, S.; Majumdar, N.; Bhattacharya, P.; Jash, A.; Bhattacharya, D. S.

    2016-10-01

    Many important problems in several branches of science and technology deal with charges distributed along a line, over a surface and within a volume. Recently, we have made use of new exact analytic solutions of surface charge distributions to develop the nearly exact Boundary Element Method (neBEM) toolkit. This 3D solver has been successful in removing some of the major drawbacks of the otherwise elegant Green's function approach and has been found to be very accurate throughout the computational domain, including near- and far-field regions. Use of truly distributed singularities (in contrast to nodally concentrated ones) on rectangular and right-triangular elements used for discretizing any three-dimensional geometry has essentially removed many of the numerical and physical singularities associated with the conventional BEM. In this work, we will present this toolkit and the development of several numerical models of space charge based on exact closed-form expressions. In one of the models, Particles on Surface (ParSur), the space charge inside a small elemental volume of any arbitrary shape is represented as being smeared on several surfaces representing the volume. From the studies, it can be concluded that the ParSur model is successful in getting the estimates close to those obtained using the first-principles, especially close to and within the cell. In the paper, we will show initial applications of ParSur and other models in problems related to high energy physics.

  5. 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.

  6. Evaluation criteria for bioaerosol samplers.

    Science.gov (United States)

    Kesavan, Jana; Sagripanti, Jose-Luis

    2015-03-01

    Humans contract a variety of serious diseases through inhalation of infectious aerosols. Thus, the importance of monitoring air for microbial, toxic, or allergic content is recognized in clinical, occupational, and biodefense arenas. However, accurate monitoring of potentially contaminated environments can be hampered by selection of aerosol samplers with inadequate performance for the intended task. In this study, 29 aerosol samplers were evaluated based on their respective air flow, size, weight, power consumption, and efficiency in sampling particles in the respirable range. The resulting data demonstrates that sampling air flow and efficiency vary widely, and cannot be predicted from the physical characteristics of air samplers, and hence, that proper selection of air samplers should be more involved than shopping for a device based on the limited characteristics that are published by the manufacturers. The findings are summarized in an approach to rationally select bioaerosol samplers for use in infection control and environmental biomonitoring. The presented data demonstrates that inadequate selection of air samplers could result in a failure to collect particles of interest and thus, underestimate the risk and provide a false sense of security in contaminated health care settings and environments contaminated with infectious or toxic aerosols.

  7. Dynamics at Solid State Surfaces and Interfaces Volume 2 Fundamentals

    CERN Document Server

    Bovensiepen, Uwe; Wolf, Martin

    2012-01-01

    This two-volume work covers ultrafast structural and electronic dynamics of elementary processes at solid surfaces and interfaces, presenting the current status of photoinduced processes. Providing valuable introductory information for newcomers to this booming field of research, it investigates concepts and experiments, femtosecond and attosecond time-resolved methods, as well as frequency domain techniques.The whole is rounded off by a look at future developments.

  8. Mapping of tritium emissions using absorption vapour samplers.

    Science.gov (United States)

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

    2009-02-01

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

  9. Calibration and application of PUF disk passive air samplers for tracking polycyclic aromatic compounds (PACs)

    Science.gov (United States)

    Harner, Tom; Su, Ky; Genualdi, Susie; Karpowicz, Jessica; Ahrens, Lutz; Mihele, Cristian; Schuster, Jasmin; Charland, Jean-Pierre; Narayan, Julie

    2013-08-01

    Results are reported from a field calibration of the polyurethane foam (PUF) disk passive air sampler for measuring polycyclic aromatic compounds (PACs) in the atmosphere of the Alberta oil sands region of Canada. Passive samplers were co-deployed alongside conventional high volume samplers at three sites. The results demonstrate the ability of the PUF disk sampler to capture PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs and parent and alkylated dibenzothiophenes. Both gas- and particle-phase PACs were captured with an average sampling rate of approximately 5 m3 day-1, similar to what has been previously observed for other semivolatile compounds. This is the first application of the PUF disk sampler for alkylated PAHs and dibenzothiophenes in air. The derived sampling rates are combined with estimates of the equilibrium partitioning of the PACs in the PUF disk samplers to estimate effective sample air volumes for all targeted PACs. This information is then applied to the passive sampling results from two deployments across 17 sites in the region to generate spatial maps of PACs. The successful calibration of the sampler and development of the methodology for deriving air concentrations lends support to the application of this cost-effective and simple sampler in longer term studies of PACs in the oil sands region.

  10. Collective phenomena in volume and surface barrier discharges

    Science.gov (United States)

    Kogelschatz, U.

    2010-11-01

    Barrier discharges are increasingly used as a cost-effective configuration to produce non-equilibrium plasmas at atmospheric pressure. This way, copious amounts of electrons, ions, free radicals and excited species can be generated without significant heating of the background gas. In most applications the barrier is made of dielectric material. Major applications utilizing mainly dielectric barriers include ozone generation, surface cleaning and modification, polymer and textile treatment, sterilization, pollution control, CO2 lasers, excimer lamps, plasma display panels (flat TV screens). More recent research efforts are devoted to biomedical applications and to plasma actuators for flow control. Sinusoidal feeding voltages at various frequencies as well as pulsed excitation schemes are used. Volume as well as surface barrier discharges can exist in the form of filamentary, regularly patterned or diffuse, laterally homogeneous discharges. The physical effects leading to collective phenomena in volume and surface barrier discharges are discussed in detail. Special attention is paid to self-organization of current filaments and pattern formation. Major similarities of the two types of barrier discharges are elaborated.

  11. Rapid surface-water volume estimations in beaver ponds

    Science.gov (United States)

    Karran, Daniel J.; Westbrook, Cherie J.; Wheaton, Joseph M.; Johnston, Carol A.; Bedard-Haughn, Angela

    2017-02-01

    Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range of environmental settings in which beaver ponds are found. Studied were a total of 40 beaver ponds from four different sites in North and South America. The simplified volume-area-depth (V-A-h) approach, originally developed for prairie potholes, was tested. With only two measurements of pond depth and corresponding surface area, this method estimated surface-water storage in beaver ponds within 5 % on average. Beaver pond morphometry was characterized by a median basin coefficient of 0.91, and dam length and pond surface area were strongly correlated with beaver pond storage capacity, regardless of geographic setting. These attributes provide a means for coarsely estimating surface-water storage capacity in beaver ponds. Overall, this research demonstrates that reliable estimates of surface-water storage in beaver ponds only requires simple measurements derived from aerial imagery and/or brief visits to the field. Future research efforts should be directed at incorporating these simple methods into both broader beaver-related tools and catchment-scale hydrological models.

  12. Active Hydrazine Vapor Sampler (AHVS)

    Science.gov (United States)

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

    1993-01-01

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

  13. Solid-Sorbent Air Sampler

    Science.gov (United States)

    Galen, T. J.

    1986-01-01

    Portable unit takes eight 24-hour samples. Volatile organic compounds in air collected for analysis by portable, self-contained sampling apparatus. Sampled air drawn through sorbent material, commercial porous polymer of 2, 3-diphenyl-p-phenylene oxide. High-boiling-point organic compounds adsorbed onto polymer, while low-boiling-point organics pass through and returned to atmosphere. Sampler includes eight sample tubes filled with polymeric sorbent. Organic compounds in atmosphere absorbed when air pumped through sorbent. Designed for checking air in spacecraft, sampler adaptable to other applications as leak detection, gas-mixture analysis, and ambient-air monitoring.

  14. Demonstration/Validation of the Snap Sampler

    Science.gov (United States)

    2011-06-01

    Department of Environmental Protection PAH Polycyclic Aromatic Hydrocarbon PDB Polyethylene Diffusion Bag sampler PE Polyethylene POC Points of Contact...sampler can undergo biodegradation , using this sampler can necessitate two trips to the field: one to deploy the sampler and the other to retrieve the...these substances were released into the envi- ronment. Specifically, fuels, organic solvents, polycyclic aromatic hydrocarbons ( PAHs ), and metals have

  15. A modified siphon sampler for shallow water

    Science.gov (United States)

    Diehl, Timothy H.

    2008-01-01

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

  16. Static contact angle versus volume of distilled water drop on micro patterned surfaces

    OpenAIRE

    Batichsheva Kseniya; Feoktistov Dmitriy; Ovchinikov Vladimir; Misyura Sergey

    2017-01-01

    Static contact angle was determined experimentally in the condition of wetting of polished and laser patterned surfaces of stainless steel substrates by distilled water drops with different volumes. In contrast with polished surface, the contact angle was found to depend on drop volume on micro patterned surfaces. In addition, the enhancement of both hydrophilic and hydrophobic properties was observed on laser patterned surfaces.

  17. SAVANNAH RIVER SITE TANK 18 AND TANK 19 WALL SAMPLER PERFORMANCE

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, R.; Thaxton, D.; Minichan, R.; France, T.; Steeper, T.; Corbett, J.; Martin, B.; Vetsch, B.

    2009-12-19

    A sampling tool was required to evaluate residual activity ({mu}Curies per square foot) on the inner wall surfaces of underground nuclear waste storage tanks. The tool was required to collect a small sample from the 3/8 inch thick tank walls. This paper documents the design, testing, and deployment of the remotely operated sampling device. The sampler provides material from a known surface area to estimate the overall surface contamination in the tank prior to closure. The sampler consisted of a sampler and mast assembly mast assembly, control system, and the sampler, or end effector, which is defined as the operating component of a robotic arm. The mast assembly consisted of a vertical 30 feet long, 3 inch by 3 inch, vertical steel mast and a cantilevered arm hinged at the bottom of the mast and lowered by cable to align the attached sampler to the wall. The sampler and mast assembly were raised and lowered through an opening in the tank tops, called a riser. The sampler is constructed of a mounting plate, a drill, springs to provide a drive force to the drill, a removable sampler head to collect the sample, a vacuum pump to draw the sample from the drill to a filter, and controls to operate the system. Once the sampler was positioned near the wall, electromagnets attached it to the wall, and the control system was operated to turn on the drill and vacuum to remove and collect a sample from the wall. Samples were collected on filters in removable sampler heads, which were readily transported for further laboratory testing.

  18. Design of Finite Element Tools for Coupled Surface and Volume Meshes

    Institute of Scientific and Technical Information of China (English)

    Daniel K(o)ster; Oliver Kriessl; Kunibert G. Siebert

    2008-01-01

    Many problems with underlying variational structure involve a coupling of volume with surface effects. A straight-forward approach in a finite element discretization is to make use of the surface triangulation that is naturally induced by the volume triangulation. In an adaptive method one wants to facilitate "matching" local mesh modifications, i.e., local refinement and/or coarsening, of volume and surface mesh with standard tools such that the surface grid is always induced by the volume grid. We describe the concepts behind this approach for bisectional refinement and describe new tools incorporated in the finite element toolbox ALBERTA. We also present several important applications of the mesh coupling.

  19. [Assessment of measured respirable dust sampler penetration and the sampling convention for work environment measurement].

    Science.gov (United States)

    Myojo, Toshihiko

    2005-11-01

    The relationship between dust size and penetration for a static horizontal elutriator (Sibata C-30) was measured in calm air. The elutriator as a low-volume air sampler is widely used as a dust size classifier in work environment measurements. The actual penetrations were compared with the theoretical models of the sampler and with sampling convention for respirable dust in work environment measurement. The sampling convention was recently introduced into the Japanese standard for work environment measurement and is based on the ISO 7708 respirable dust convention. The bias of sampled masses from the respirable dust was calculated for two flow rates of the sampler, i.e., 50% cut sizes of 4 microm and 5 microm, from measured penetration curves. The bias of the sampler was overestimated in the 5 microm, 50% cut condition and underestimated in the 4 microm, 50% cut condition for most workplace sampling situations.

  20. Static contact angle versus volume of distilled water drop on micro patterned surfaces

    Directory of Open Access Journals (Sweden)

    Batichsheva Kseniya

    2017-01-01

    Full Text Available Static contact angle was determined experimentally in the condition of wetting of polished and laser patterned surfaces of stainless steel substrates by distilled water drops with different volumes. In contrast with polished surface, the contact angle was found to depend on drop volume on micro patterned surfaces. In addition, the enhancement of both hydrophilic and hydrophobic properties was observed on laser patterned surfaces.

  1. Human lung volume, alveolar surface area, and capillary length

    DEFF Research Database (Denmark)

    Wiebe, B. M.; Laursen, Henning

    1995-01-01

    Cavalieri's principle, length density, morphometry, stereology, surface density, vertical sections, vertical slices......Cavalieri's principle, length density, morphometry, stereology, surface density, vertical sections, vertical slices...

  2. 52nd colloid and surface science symposium. Proceedings volume

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, E.L. Jr.; Corbett, H.G.

    1978-05-01

    Abstracts are presented under the headings: cell/surface interactions, surface properties and reactions of catalysts, solution chemistry of surfactants, dynamic systems, microorganism/surface interactions, gas-solid interactions, biological surfaces, solid sorbents, lung surfactant and intestinal absorption, pigments, and liquid systems. (DLC)

  3. 7 CFR 29.20 - Sampler.

    Science.gov (United States)

    2010-01-01

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

  4. Performance evaluation of two personal bioaerosol samplers.

    Science.gov (United States)

    Tolchinsky, Alexander D; Sigaev, Vladimir I; Varfolomeev, Alexander N; Uspenskaya, Svetlana N; Cheng, Yung S; Su, Wei-Chung

    2011-01-01

    In this study, the performance of two newly developed personal bioaerosol samplers for monitoring the level of environmental and occupational airborne microorganisms was evaluated. These new personal bioaerosol samplers were designed based on a swirling cyclone with recirculating liquid film. The performance evaluation included collection efficiency tests using inert aerosols, the bioaerosol survival test using viable airborne microorganism, and the evaluation of using non-aqueous collection liquid for long-period sampling. The test results showed that these two newly developed personal bioaerosol samplers are capable of doing high efficiency, aerosol sampling (the cutoff diameters are around 0.7 μm for both samplers), and have proven to provide acceptable survival for the collected bioaerosols. By using an appropriate non-aqueous collection liquid, these two personal bioaerosol samplers should be able to permit continuous, long-period bioaerosol sampling with considerable viability for the captured bioaerosols.

  5. Historical volume estimation and a structured method for calculating habitable volume for in-space and surface habitats

    Science.gov (United States)

    Simon, M.; Bobskill, M. R.; Wilhite, A.

    2012-11-01

    Habitable volume is an important spacecraft design figure of merit necessary to determine the required size of crewed space vehicles, or habitats. In order to design habitats for future missions and properly compare the habitable volumes of future habitat designs with historical spacecraft, consistent methods of both defining the required amount of habitable volume and estimating the habitable volume for a given layout are required. This paper provides a brief summary of historical habitable volume requirements and describes the appropriate application of requirements to various types of missions, particularly highlighting the appropriate application for various gravity environments. Then the proposed "Marching Grid Method", a structured automatic, numerical method to calculate habitable volume for a given habitat design, is described in detail. This method uses a set of geometric Boolean tests applied to a discrete set of points within the pressurized volume to numerically estimate the functionally usable and accessible space that comprises the habitable volume. The application of this method to zero gravity and nonzero gravity environments is also discussed. This proposed method is then demonstrated by calculating habitable volumes using two conceptual-level layouts of habitat designs, one for each type of gravity environment. These include the US Laboratory Module on ISS and the Scenario 12.0 Pressurized Core Module from the recent NASA Lunar Surface Systems studies. Results of this study include a description of the effectiveness of this method for various resolutions of the investigated grid, and commentary highlighting the use of this method to determine the overall utility of interior configurations for automatically evaluating interior layouts.

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

    Science.gov (United States)

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

    2003-06-01

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

  7. Measuring air layer volumes retained by submerged floating-ferns Salvinia and biomimetic superhydrophobic surfaces

    Directory of Open Access Journals (Sweden)

    Matthias J. Mayser

    2014-06-01

    Full Text Available Some plants and animals feature superhydrophobic surfaces capable of retaining a layer of air when submerged under water. Long-term air retaining surfaces (Salvinia-effect are of high interest for biomimetic applications like drag reduction in ship coatings of up to 30%. Here we present a novel method for measuring air volumes and air loss under water. We recorded the buoyancy force of the air layer on leaf surfaces of four different Salvinia species and on one biomimetic surface using a highly sensitive custom made strain gauge force transducer setup. The volume of air held by a surface was quantified by comparing the buoyancy force of the specimen with and then without an air layer. Air volumes retained by the Salvinia-surfaces ranged between 0.15 and 1 L/m2 depending on differences in surface architecture. We verified the precision of the method by comparing the measured air volumes with theoretical volume calculations and could find a good agreement between both values. In this context we present techniques to calculate air volumes on surfaces with complex microstructures. The introduced method also allows to measure decrease or increase of air layers with high accuracy in real-time to understand dynamic processes.

  8. Three-dimensional wavelet transform and multiresolution surface reconstruction from volume data

    Science.gov (United States)

    Wang, Yun; Sloan, Kenneth R., Jr.

    1995-04-01

    Multiresolution surface reconstruction from volume data is very useful in medical imaging, data compression and multiresolution modeling. This paper presents a hierarchical structure for extracting multiresolution surfaces from volume data by using a 3-D wavelet transform. The hierarchical scheme is used to visualize different levels of detail of the surface and allows a user to explore different features of the surface at different scales. We use 3-D surface curvature as a smoothness condition to control the hierarchical level and the distance error between the reconstructed surface and the original data as the stopping criteria. A 3-D wavelet transform provides an appropriate hierarchical structure to build the volume pyramid. It can be constructed by the tensor products of 1-D wavelet transforms in three subspaces. We choose the symmetric and smoothing filters such as Haar, linear, pseudoCoiflet, cubic B-spline and their corresponding orthogonal wavelets to build the volume pyramid. The surface is reconstructed at each level of volume data by using the cell interpolation method. Some experimental results are shown through the comparison of the different filters based on the distance errors of the surfaces.

  9. Calibration of Polyurethane Foam (PUF Disk Passive Air Samplers for Quantitative Sampling of Polychlorinated Biphenyls (PCBs and Polybrominated Diphenyl Ethers (PBDEs in Indoor Air

    Directory of Open Access Journals (Sweden)

    S Hazrati

    2005-10-01

    Full Text Available In order to employ PUF disk passive air sampler (140 mm diameter, 12 mm thickness as a quantitative sampling device a set of calibration experiments were carried out. Time integrated indoor air concentrations of PCBs and PBDEs were obtained from a low volume air sampler. The low volume active sampler was run alongside the passive samplers throughout the calibration period in an office microenvironment. Sampling rates of routinely employed passive sampler design were determined for 51 PCB and 6 PBDE congeners detected in all calibration samples. PUF disk R-values varied from 0.63 to 1.54 m3 day-1 for individual PCBs and from 1.1 to 1.9 m3 day-1 for PBDE congeners. The theory of passive sampling is also discussed and mass transfer coefficients (kA of PCB and PBDE congeners provided.

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

    Science.gov (United States)

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

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

  11. The MAGIC meteoric smoke particle sampler

    Science.gov (United States)

    Hedin, Jonas; Giovane, Frank; Waldemarsson, Tomas; Gumbel, Jörg; Blum, Jürgen; Stroud, Rhonda M.; Marlin, Layne; Moser, John; Siskind, David E.; Jansson, Kjell; Saunders, Russell W.; Summers, Michael E.; Reissaus, Philipp; Stegman, Jacek; Plane, John M. C.; Horányi, Mihály

    2014-10-01

    Between a few tons to several hundred tons of meteoric material enters the Earth's atmosphere each day, and most of this material is ablated and vaporized in the 70-120 km altitude region. The subsequent chemical conversion, re-condensation and coagulation of this evaporated material are thought to form nanometre sized meteoric smoke particles (MSPs). These smoke particles are then subject to further coagulation, sedimentation and global transport by the mesospheric circulation. MSPs have been proposed as a key player in the formation and evolution of ice particle layers around the mesopause region, i.e. noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE). MSPs have also been implicated in mesospheric heterogeneous chemistry to influence the mesospheric odd oxygen/odd hydrogen (Ox/HOx) chemistry, to play an important role in the mesospheric charge balance, and to be a significant component of stratospheric aerosol and enhance the depletion of O3. Despite their apparent importance, little is known about the properties of MSPs and none of the hypotheses can be verified without direct evidence of the existence, altitude and size distribution, shape and elemental composition. The aim of the MAGIC project (Mesospheric Aerosol - Genesis, Interaction and Composition) was to develop an instrument and analysis techniques to sample for the first time MSPs in the mesosphere and return them to the ground for detailed analysis in the laboratory. MAGIC meteoric smoke particle samplers have been flown on several sounding rocket payloads between 2005 and 2011. Several of these flights concerned non-summer mesosphere conditions when pure MSP populations can be expected. Other flights concerned high latitude summer conditions when MSPs are expected to be contained in ice particles in the upper mesosphere. In this paper we present the MAGIC project and describe the MAGIC MSP sampler, the measurement procedure and laboratory analysis. We also present the attempts to

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

    Science.gov (United States)

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

    2002-01-01

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

  13. Volume radiation generated by a medium-IR SEW propagating on a smooth metal surface

    Energy Technology Data Exchange (ETDEWEB)

    Libenson, M.N.; Makin, V.S.; Trubaev, V.V. [Vavilov State Optical Inst., St. Petersburg (Russian Federation)

    1995-03-01

    The volume wave radiating from a smooth surface region that guides an SEW is shown to be a grazing wave; in earlier experiments, this wave was detected at relatively large angles with respect to the surface. 4 refs., 2 figs., 1 tab.

  14. 3D automatic segmentation method for retinal optical coherence tomography volume data using boundary surface enhancement

    Directory of Open Access Journals (Sweden)

    Yankui Sun

    2016-03-01

    Full Text Available With the introduction of spectral-domain optical coherence tomography (SD-OCT, much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, there is a critical need for the development of three-dimensional (3D segmentation methods for processing these data. We present here a novel 3D automatic segmentation method for retinal OCT volume data. Briefly, to segment a boundary surface, two OCT volume datasets are obtained by using a 3D smoothing filter and a 3D differential filter. Their linear combination is then calculated to generate new volume data with an enhanced boundary surface, where pixel intensity, boundary position information, and intensity changes on both sides of the boundary surface are used simultaneously. Next, preliminary discrete boundary points are detected from the A-Scans of the volume data. Finally, surface smoothness constraints and a dynamic threshold are applied to obtain a smoothed boundary surface by correcting a small number of error points. Our method can extract retinal layer boundary surfaces sequentially with a decreasing search region of volume data. We performed automatic segmentation on eight human OCT volume datasets acquired from a commercial Spectralis OCT system, where each volume of datasets contains 97 OCT B-Scan images with a resolution of 496×512 (each B-Scan comprising 512 A-Scans containing 496 pixels; experimental results show that this method can accurately segment seven layer boundary surfaces in normal as well as some abnormal eyes.

  15. Size dependence of volume and surface nucleation rates for homogeneous freezing of supercooled water droplets

    Directory of Open Access Journals (Sweden)

    T. Kuhn

    2009-10-01

    Full Text Available We investigated the relative roles of volume and surface nucleation in the freezing of water droplets. Nucleation experiments were carried out in a cryogenic laminar aerosol flow tube using supercooled liquid water aerosols with radii between about 1 and 3 μ m. Temperature- and size-dependent values of volume- and surface-based homogeneous nucleation rate between 234.8 and 236.2 K are derived with help of a microphysical model from aerosol compositions and size distributions based on infrared extinction measurements in the aerosol flow tube. The results show that the contribution from nucleation at the droplet surface increases with decreasing droplet radius and dominates over nucleation in the bulk droplet volume for droplets with radii smaller than approximately 5 μm. This is interpreted in terms of a lowered free energy of ice germ formation in the surface-based process and has implications for the parameterization of homogeneous ice nucleation in numerical models.

  16. Do skeletal cephalometric characteristics correlate with condylar volume, surface and shape? A 3D analysis

    Directory of Open Access Journals (Sweden)

    Saccucci Matteo

    2012-05-01

    Full Text Available Abstract Objective The purpose of this study was to determine the condylar volume in subjects with different mandibular divergence and skeletal class using cone-beam computed tomography (CBCT and analysis software. Materials and methods For 94 patients (46 females and 48 males; mean age 24.3 ± 6.5 years, resultant rendering reconstructions of the left and right temporal mandibular joints (TMJs were obtained. Subjects were then classified on the base of ANB angle the GoGn-SN angle in three classes (I, II, III . The data of the different classes were compared. Results No significant difference was observed in the whole sample between the right and the left sides in condylar volume. The analysis of mean volume among low, normal and high mandibular plane angles revealed a significantly higher volume and surface in low angle subjects (p  Class III subjects also tended to show a higher condylar volume and surface than class I and class II subjects, although the difference was not significant. Conclusions Higher condylar volume was a common characteristic of low angle subjects compared to normal and high mandibular plane angle subjects. Skeletal class also appears to be associated to condylar volume and surface.

  17. Radiative properties of materials with surface scattering or volume scattering: A review

    Institute of Scientific and Technical Information of China (English)

    Qunzhi ZHU; Hyunjin LEE; Zhuomin M. ZHANG

    2009-01-01

    Radiative properties of rough surfaces, parti-culate media and porous materials are important in thermal engineering and many other applications. These properties are often needed for calculating heat transfer between surfaces and volume elements in participating media, as well as for accurate radiometric temperature measure-ments. In this paper, recent research on scattering of thermal radiation by rough surfaces, fibrous insulation, soot, aerogel, biological materials, and polytetrafluor-oethylene (PTFE) is reviewed. Both theoretical modeling and experimental investigation are discussed. Rigorous solutions and approximation methods for surface scattering and volume scattering are described. The approach of using measured surface roughness statistics in Monte Carlo simulations to predict radiative properties of rough surfaces is emphasized. The effects of various parameters on the radiative properties of particulate media and porous materials are summarized.

  18. Characterization Investigation Study: Volume 3, Radiological survey of surface soils

    Energy Technology Data Exchange (ETDEWEB)

    Solow, A.J.; Phoenix, D.R.

    1987-12-01

    The Feed Materials Production Center was constructed to produce high purity uranium metal for use at various Department of Energy facilities. The waste products from these operations include general uncontaminated scrap and refuse, contaminated and uncontaminated metal scrap, waste oils, low-level radioactive waste, co-contaminated wastes, mixed waste, toxic waste, sludges from water treatment, and fly ash from the steam plant. This material is estimated to total more than 350,000 cubic meters. Other wastes stored in this area include laboratory chemicals and other combustible materials in the burn pit; fine waste stream sediments in the clear well; fly ash and waste oils in the two fly ash areas; lime-alum sludges and boiler plant blowdown in the lime sludge ponds; and nonradioactive sanitary waste, construction rubble, and asbestos in the sanitary landfill. A systematic survey of the surface soils throughout the Waste Storage Area, associated on-site drainages, and the fly ash piles was conducted using a Field Instrument for Detecting Low-Energy Radiation (FIDLER). Uranium is the most prevalent radioactive element in surface soil; U-238 is the principal radionuclide, ranging from 2.2 to 1790 pCi/g in the general Waste Storage Area. The maximum values for the next highest activity concentrations in the same area were 972 pCi/g for Th-230 and 298 pCi/g for U-234. Elevated activity concentrations of Th-230 were found along the K-65 slurry line, the maximum at 3010 pCi/g. U-238 had the highest value of 761 pCi/g in the drainage just south of pit no. 5. The upper fly ash area had the highest radionuclide activity concentrations in the surface soils with the maximum values for U-238 at 8600 pCi/g, U-235 at 2190 pCi/g, U-234 at 11,400 pCi/g, Tc-99 at 594 pCi/g, Ra-226 at 279 pCi/g, and Th-230 at 164 pCi/g.

  19. The impact of surface area, volume, curvature, and Lennard-Jones potential to solvation modeling.

    Science.gov (United States)

    Nguyen, Duc D; Wei, Guo-Wei

    2017-01-05

    This article explores the impact of surface area, volume, curvature, and Lennard-Jones (LJ) potential on solvation free energy predictions. Rigidity surfaces are utilized to generate robust analytical expressions for maximum, minimum, mean, and Gaussian curvatures of solvent-solute interfaces, and define a generalized Poisson-Boltzmann (GPB) equation with a smooth dielectric profile. Extensive correlation analysis is performed to examine the linear dependence of surface area, surface enclosed volume, maximum curvature, minimum curvature, mean curvature, and Gaussian curvature for solvation modeling. It is found that surface area and surfaces enclosed volumes are highly correlated to each other's, and poorly correlated to various curvatures for six test sets of molecules. Different curvatures are weakly correlated to each other for six test sets of molecules, but are strongly correlated to each other within each test set of molecules. Based on correlation analysis, we construct twenty six nontrivial nonpolar solvation models. Our numerical results reveal that the LJ potential plays a vital role in nonpolar solvation modeling, especially for molecules involving strong van der Waals interactions. It is found that curvatures are at least as important as surface area or surface enclosed volume in nonpolar solvation modeling. In conjugation with the GPB model, various curvature-based nonpolar solvation models are shown to offer some of the best solvation free energy predictions for a wide range of test sets. For example, root mean square errors from a model constituting surface area, volume, mean curvature, and LJ potential are less than 0.42 kcal/mol for all test sets. © 2016 Wiley Periodicals, Inc.

  20. A Gibbs Sampler for Learning DAGs

    Science.gov (United States)

    Goudie, Robert J. B.; Mukherjee, Sach

    2017-01-01

    We propose a Gibbs sampler for structure learning in directed acyclic graph (DAG) models. The standard Markov chain Monte Carlo algorithms used for learning DAGs are random-walk Metropolis-Hastings samplers. These samplers are guaranteed to converge asymptotically but often mix slowly when exploring the large graph spaces that arise in structure learning. In each step, the sampler we propose draws entire sets of parents for multiple nodes from the appropriate conditional distribution. This provides an efficient way to make large moves in graph space, permitting faster mixing whilst retaining asymptotic guarantees of convergence. The conditional distribution is related to variable selection with candidate parents playing the role of covariates or inputs. We empirically examine the performance of the sampler using several simulated and real data examples. The proposed method gives robust results in diverse settings, outperforming several existing Bayesian and frequentist methods. In addition, our empirical results shed some light on the relative merits of Bayesian and constraint-based methods for structure learning.

  1. Photoelectron emission from plasmonic nanoparticles: Comparison between surface and volume photoelectric effects

    CERN Document Server

    Uskov, Alexander V; Ikhsanov, Renat Sh; Babicheva, Viktoriia E; Zhukovsky, Sergei V; Lavrinenko, Andrey V; OReilly, Eoin P; Xu, Hongxing

    2013-01-01

    We study emission of photoelectrons from plasmonic nanoparticles into surrounding matrix. We consider two mechanisms of the photoelectric effect from nanoparticles - surface and volume ones, and use models of these two effects which allow us to obtain analytical results for the photoelectron emission rates from nanoparticle. Calculations have been done for the step potential at surface of spherical nanoparticle, and the simple model for the hot electron cooling have been used. We highlight the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary in the surface mechanism, which leads to substantial (by 5 times) increase of photoelectron emission rate from nanoparticle compared to the case when such discontinuity is absent. For plasmonic nanoparticle, a comparison of two mechanisms of the photoeffect was done for the first time and showed that surface photoeffect, at least, does not concede the volume one, which agrees with results for the flat metal surface first formulated b...

  2. Volume and surface contributions to the nuclear symmetry energy within the coherent density fluctuation model

    CERN Document Server

    Antonov, A N; Sarriguren, P; de Guerra, E Moya

    2016-01-01

    The volume and surface components of the nuclear symmetry energy (NSE) and their ratio are calculated within the coherent density fluctuation model (CDFM). The estimations use the results of the model for the NSE in finite nuclei based on the Brueckner energy-density functional for nuclear matter. In addition, we present results for the NSE and its volume and surface contributions obtained by using the Skyrme energy-density functional. The CDFM weight function is obtained using the proton and neutron densities from the self-consistent HF+BCS method with Skyrme interactions. We present and discuss the values of the volume and surface contributions to the NSE and their ratio obtained for the Ni, Sn, and Pb isotopic chains studying their isotopic sensitivity. The results are compared with estimations of other approaches which have used available experimental data on binding energies, neutron-skin thicknesses, excitation energies to isobaric analog states (IAS) and also with results of other theoretical methods.

  3. 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.

  4. Longitudinal in vivo reproducibility of cartilage volume and surface in osteoarthritis of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Brem, M.H. [Harvard Medical School, Brigham and Women' s Hospital, Musculoskeletal Division, Department of Radiology, ASB-1, L-1, Room 003E, Boston, MA (United States); University of Erlangen-Nuremberg, Division of Trauma Surgery and Orthopaedic Surgery, Department of Surgery, Erlangen (Germany); Pauser, J.; Yoshioka, H.; Stratmann, J.; Kikinis, R.; Duryea, J.; Lang, P. [Harvard Medical School, Brigham and Women' s Hospital, Musculoskeletal Division, Department of Radiology, ASB-1, L-1, Room 003E, Boston, MA (United States); Brenning, A. [University of Erlangen-Nuremberg, Department of Medical Informatics, Biometry and Epidemiology, Erlangen (Germany); Hennig, F.F. [University of Erlangen-Nuremberg, Division of Trauma Surgery and Orthopaedic Surgery, Department of Surgery, Erlangen (Germany); Winalski, C.S. [Harvard Medical School, Brigham and Women' s Hospital, Musculoskeletal Division, Department of Radiology, ASB-1, L-1, Room 003E, Boston, MA (United States); Cleveland Clinic Foundation, Division of Radiology, Cleveland, OH (United States)

    2007-04-15

    The aim of this study was to evaluate the longitudinal reproducibility of cartilage volume and surface area measurements in moderate osteoarthritis (OA) of the knee. We analysed 5 MRI (GE 1.5T, sagittal 3D SPGR) data sets of patients with osteoarthritis (OA) of the knee (Kellgren Lawrence grade I-II). Two scans were performed: one baseline scan and one follow-up scan 3 months later (96 {+-} 10 days). For segmentation, 3D Slicer 2.5 software was used. Two segmentations were performed by two readers independently who were blinded to the scan dates. Tibial and femoral cartilage volume and surface were determined. Longitudinal and cross-sectional precision errors were calculated using the standard deviation (SD) and coefficient of variation (CV%=100 x [SD/mean]) from the repeated measurements in each patient. The in vivo reproducibility was then calculated as the root mean square of these individual reproducibility errors. The cross-sectional root mean squared coefficient of variation (RMSE-CV) was 1.2, 2.2 and 2.4% for surface area measurements (femur, medial and lateral tibia respectively) and 1.4, 1.8 and 1.3% for the corresponding cartilage volumes. Longitudinal RMSE-CV was 3.3, 3.1 and 3.7% for the surface area measurements (femur, medial and lateral tibia respectively) and 2.3, 3.3 and 2.4% for femur, medial and lateral tibia cartilage volumes. The longitudinal in vivo reproducibility of cartilage surface and volume measurements in the knee using this segmentation method is excellent. To the best of our knowledge we measured, for the first time, the longitudinal reproducibility of cartilage volume and surface area in participants with mild to moderate OA. (orig.)

  5. Size dependence of volume and surface nucleation rates for homogeneous freezing of supercooled water droplets

    Directory of Open Access Journals (Sweden)

    T. Kuhn

    2011-03-01

    Full Text Available The relative roles of volume and surface nucleation were investigated for the homogeneous freezing of pure water droplets. Experiments were carried out in a cryogenic laminar aerosol flow tube using supercooled water aerosols with maximum volume densities at radii between 1 and 3 μm. Temperature- and size-dependent values of volume- and surface-based homogeneous nucleation rates between 234.8 and 236.2 K were derived using a microphysical model and aerosol phase compositions and size distributions determined from infrared extinction measurements in the flow tube. The results show that the contribution from nucleation at the droplet surface increases with decreasing droplet radius and dominates over nucleation in the bulk droplet volume for droplets with radii smaller than approximately 5 μm. This is interpreted in terms of a lowered free energy of ice germ formation in the surface-based process. The implications of surface nucleation for the parameterization of homogeneous ice nucleation in numerical models are considered.

  6. Angiosperms evolved a higher mesophyll surface area per volume to maximize exchange surface under a low CO2 world

    Science.gov (United States)

    Théroux-Rancourt, Guillaume; Mason Earles, J.; Gilbert, Matthew E.; Zwieniecki, Maciej A.; Boyce, C. Kevin; McElrone, Andrew; Brodersen, Craig

    2017-04-01

    Variation in leaf mesophyll structure strongly affects CO2 diffusion and photosynthetic rates. One key trait is the surface of mesophyll cells exposed to intercellular airspace (Sm) which increases mesophyll conductance. Consequently, Sm is a key control of CO2 diffusion among species and genotypes. Using Sm values from the literature (> 200 species with 500 data points) and from our high-resolution X-ray computed tomography (μCT) dataset (currently 117 species), Sm shows little variation from pteridophytes to early angiosperms, while eudicots show the greatest structural diversity. However, Sm increases with total thickness of the mesophyll. By considering the exposed surface of the mesophyll to the intercellular air space (IAS) on a leaf or mesophyll volume (Ames/V mes) rather than leaf area basis (Sm), we demonstrate that angiosperms, and most specifically commelinids and non-basal eudicots, have constructed leaves with more surface per volume, while gymnosperms keep a constant Ames/V mes ratio. Thus, this strong phylogenetic signal suggests that angiosperms have developed IAS properties favoring leaves with higher surface to volume ratio, trait that allowed for the potential of high productivity even as atmospheric CO2 declined over the Cenozoic.

  7. Validity and repeatability of a depth camera-based surface imaging system for thigh volume measurement.

    Science.gov (United States)

    Bullas, Alice M; Choppin, Simon; Heller, Ben; Wheat, Jon

    2016-10-01

    Complex anthropometrics such as area and volume, can identify changes in body size and shape that are not detectable with traditional anthropometrics of lengths, breadths, skinfolds and girths. However, taking these complex with manual techniques (tape measurement and water displacement) is often unsuitable. Three-dimensional (3D) surface imaging systems are quick and accurate alternatives to manual techniques but their use is restricted by cost, complexity and limited access. We have developed a novel low-cost, accessible and portable 3D surface imaging system based on consumer depth cameras. The aim of this study was to determine the validity and repeatability of the system in the measurement of thigh volume. The thigh volumes of 36 participants were measured with the depth camera system and a high precision commercially available 3D surface imaging system (3dMD). The depth camera system used within this study is highly repeatable (technical error of measurement (TEM) of <1.0% intra-calibration and ~2.0% inter-calibration) but systematically overestimates (~6%) thigh volume when compared to the 3dMD system. This suggests poor agreement yet a close relationship, which once corrected can yield a usable thigh volume measurement.

  8. Air quality assessment in Southern Kuwait using diffusive passive samplers.

    Science.gov (United States)

    Ramadan, A A

    2010-01-01

    Measurements of fortnightly average concentrations of NO, NO2, SO2, H2S, NH3, and volatile organic compounds (VOCs) (aromatics=benzene, toluene, o-xylene, m+p-xylene, ethyl benzene; non-aromatics=nonane and octane) were carried out in the period from 26/10/05 to 24/11/05 at 20 points in the southern part of Kuwait as part of a baseline environmental impact assessment study requested by Kuwait National Petroleum Company. Two waves of triplicate diffusive passive samplers were used. A high volume air sampler was used to measure PM10 too. During the sampling period, the wind was observed to be mainly from the west and northwest with an average of 4.28 m/s. The consistency of the results allowed the production of spatial distribution maps of the pollutants measured and consequently the comparison between levels of air pollution at different locations. A comparison between the measured concentrations and the applicable air quality standards promulgated by Kuwait Environment Public Authority (KEPA) showed that those compounds had low concentrations compared to both industrial and residential KEPA standards. For other compounds which are not covered by KEPA standards, the results were compared with relevant limits of US Environment Protect Agency (USEPA) and US Department of Labor, Occupational Safety and Health Administration. The comparison showed that the measured compounds had low concentrations compared to the existing standards and, accordingly, no violation of air quality standards is reported.

  9. 21 CFR 884.1550 - Amniotic fluid sampler (amniocentesis tray).

    Science.gov (United States)

    2010-04-01

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

  10. Internal photoemission from plasmonic nanoparticles: comparison between surface and volume photoelectric effects.

    Science.gov (United States)

    Uskov, Alexander V; Protsenko, Igor E; Ikhsanov, Renat S; Babicheva, Viktoriia E; Zhukovsky, Sergei V; Lavrinenko, Andrei V; O'Reilly, Eoin P; Xu, Hongxing

    2014-05-01

    We study the emission of photoelectrons from plasmonic nanoparticles into a surrounding matrix. We consider two mechanisms of electron emission from the nanoparticles--surface and volume ones--and use models for these two mechanisms which allow us to obtain analytical results for the photoelectron emission rate from a nanoparticle. Calculations have been carried out for a step potential at the surface of a spherical nanoparticle, and a simple model for the hot electron cooling has been used. We highlight the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary in the surface mechanism, which leads to a substantial (by ∼5 times) increase of the internal photoelectron emission rate from a nanoparticle compared to the case when such a discontinuity is absent. For a plasmonic nanoparticle, a comparison of the two photoeffect mechanisms was undertaken for the first time which showed that the surface photoeffect can in the general case be larger than the volume one, which agrees with the results obtained for a flat metal surface first formulated by Tamm and Schubin in their pioneering development of a quantum-mechanical theory of photoeffect in 1931. In accordance with our calculations, this possible predominance of the surface effect is based on two factors: (i) effective cooling of hot carriers during their propagation from the volume of the nanoparticle to its surface in the scenario of the volume mechanism and (ii) strengthening of the surface mechanism through the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary. The latter is stronger at relatively lower photon energies and correspondingly is more substantial for internal photoemission than for an external one. We show that in the general case, it is essential to take both mechanisms into account in the development of devices based on the photoelectric effect and when considering hot electron emission from a plasmonic nanoantenna.

  11. Experiment and research of air-exchange underground water sampler%气体置换式地下水采样器的研制与试验

    Institute of Scientific and Technical Information of China (English)

    李小杰; 潘德元; 叶成明; 郑继天

    2015-01-01

    To obtain groundwater sample in monitoring wells with large depth and small diameter quickly, we developed air-exchange underground water sampler. The sampler use water pressure to drive underground water into sampling tube and then use compressed air to press the water sample out of the well to ground surface. For single cycle water sampling in 550 m well, the av-erage water sampling volume is 20 L per time; while for continuous water sampling in 500 m well, the average water sampling volume is 40 L per time. This paper gives a detail introduction to the principle, design and development and test condition of the sampler.%为了能方便、快速、准确地获取小直径、大深度监测井中的地下水样品,研制了气体置换式地下水采样器。该采样器依靠水柱压力驱动地下水样品进入采样管,使用压缩气体驱动地下水样品流出地表。在采样深度500 m的单次循环采样中,采样器平均采样量为20 L/次;在同样深度的连续采样中,采样器最大采样量为40 L/h。详细介绍了采样器的技术原理、设计制作以及试验测试情况。

  12. A Robust volume conservative divergence-free ISPH framework for free-surface flow problems

    Science.gov (United States)

    Pahar, Gourabananda; Dhar, Anirban

    2016-10-01

    This study presents a Volume Conservative approach for resolving volume conservation issue in divergence-free incompressible Smoothed Particle Hydrodynamics (ISPH). Irregular free surface deformation may introduce error in volume computation, which has a cascading effect over time. Proposed correction decreases this numerical compressibility to a minimal value. The correction is obtained directly by solving Navier-Stokes momentum equation. Consequently, the framework does not require any parametric study for mixed source/sink term or iterative solution of pressure Poisson equations. The correction is implemented on four different types of flow: (a) pressurized flow in a closed box, (b) dambreak flow, (c) flow through porous block, (d) lock-exchange flow of immiscible fluids (both free-surface and pressurized flow). All four scenarios are shown to have minimal error compared to pure divergence-free ISPH.

  13. Influence of ceramic disk material, surface hemispheres, and SBF volume on in vitro mineralization.

    Science.gov (United States)

    Urquia Edreira, Eva R; Wolke, Joop G C; Jansen, John A; van den Beucken, Jeroen J J P

    2015-08-01

    Calcium phosphate ceramics are the main mineral constituents of bone and teeth and have therefore been extensively investigated for bone regenerative applications. In the current study, the effect of disk material, surface geometry, and SBF volume on mineralization capacity was investigated. Hemispherical concavities were created on the surfaces of disks made of different materials (i.e., hydroxyapatite (HA), β-tricalcium phosphate (β-TCP), biphasic calcium phosphate (BCP) and titanium (Ti)) which were sintered at 1200 °C. Mineralization of CaP was assessed on disk surfaces after immersion of the samples in different volumes of simulated body fluid (SBF) up to 14 days by means of calcium assay and scanning electron microscopy (SEM). This study showed that different SBF volumes have different effects on mineralization, with an optimum material/liquid ratio of 5 mL of SBF per cm(2) . Additionally, at this volume, apparent differences based on disk material became obvious. Evidently, surface hemispherical concavities acted as initiator areas for nucleation and crystal growth.

  14. Surface area and volume determination of subgingival calculus using laser fluorescence.

    Science.gov (United States)

    Shakibaie, Fardad; Walsh, Laurence J

    2014-03-01

    Visible red (655 nm) laser fluorescence (LF) devices are currently used for identifying deposits of subgingival calculus on the root surfaces of teeth during dental examination and treatment; however, it is not known how the fluorescence readings produced by commercially available LF systems correlate to the nature of the deposits. This laboratory study explored the correlation between LF digital readings and the surface area and volume of subgingival calculus deposits on teeth. A collection of 30 extracted human posterior teeth with various levels of subgingival deposits of calculus across 240 sites were used in a clinical simulation, with silicone impression material used to replicate periodontal soft tissues. The teeth were scored by two examiners by using three commercial LF systems (DIAGNOdent, DIAGNOdent Pen and KEY3). The silicone was removed, and the teeth were removed for photography at × 20 magnification under white or ultraviolet light. The surface area, thickness, and volume were calculated, and both linear least squares regression and nonlinear (Spearman's rank method) correlation coefficients were determined. Visible red LF digital readings showed better correlation to calculus volume than to surface area. Overall, the best performance was found for the KEY3 system (Spearman coefficient 0.59), compared to the Classic DIAGNOdent (0.56) and the DIAGNOdent Pen (0.49). These results indicate that while visible red LF systems vary somewhat in performance, their LF readings provide a useful estimation of the volume of subgingival calculus deposits present on teeth.

  15. The Surface-to-Volume Ratio in Thermal Physics: From Cheese Cube Physics to Animal Metabolism

    Science.gov (United States)

    Planinsic, Gorazd; Vollmer, Michael

    2008-01-01

    The surface-to-volume ratio is an important quantity in thermal physics. For example it governs the behaviour of heating or cooling of physical objects as a function of size like, e.g. cubes or spheres made of different material. The starting point in our paper is the simple physics problem of how cheese cubes of different sizes behave if heated…

  16. Retained gas sampler system acceptance test report

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, N.S., Westinghouse Hanford

    1996-07-18

    Acceptance test results for the Retained Gas Sampler System (RGSS) obtained in the 306E laboratory are reported. The RGSS will be utilized to retrieve and analyze samples from the Hanford flammable gas watch-list tanks to determine the quantity and chemistry of gases confined within the waste.

  17. Releasable Asbestos Field Sampler (RAFS) Operation Manual

    Science.gov (United States)

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

  18. Releasable Asbestos Field Sampler (RAFS) Operation Manual

    Science.gov (United States)

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

  19. 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.

  20. Calibration of Silicone Rubber Passive Samplers: Experimental and Modeled Relations between Sampling Rate and Compound Properties

    NARCIS (Netherlands)

    Rusina, T.P.; Smedes, F.; Koblizkova, M.; Klanova, J.

    2010-01-01

    Sampling rates (R-s) for silicone rubber (SR) passive samplers were measured under two different hydrodynamic conditions. Concentrations were maintained in the aqueous phase by continuous equilibration with SR sheets of a large total surface area which had been spiked with polycyclic aromatic hydroc

  1. Regional brain differences in cortical thickness, surface area and subcortical volume in individuals with Williams syndrome.

    Science.gov (United States)

    Meda, Shashwath A; Pryweller, Jennifer R; Thornton-Wells, Tricia A

    2012-01-01

    Williams syndrome (WS) is a rare genetic neurodevelopmental disorder characterized by increased non-social anxiety, sensitivity to sounds and hypersociability. Previous studies have reported contradictory findings with regard to regional brain variation in WS, relying on only one type of morphological measure (usually volume) in each study. The present study aims to contribute to this body of literature and perhaps elucidate some of these discrepancies by examining concurrent measures of cortical thickness, surface area and subcortical volume between WS subjects and typically-developing (TD) controls. High resolution MRI scans were obtained on 31 WS subjects and 50 typically developing control subjects. We derived quantitative regional estimates of cortical thickness, cortical surface area, and subcortical volume using FreeSurfer software. We evaluated between-group ROI differences while controlling for total intracranial volume. In post-hoc exploratory analyses within the WS group, we tested for correlations between regional brain variation and Beck Anxiety Inventory scores. Consistent with our hypothesis, we detected complex patterns of between-group cortical variation, which included lower surface area in combination with greater thickness in the following cortical regions: post central gyrus, cuneus, lateral orbitofrontal cortex and lingual gyrus. Additional cortical regions showed between-group differences in one (but not both) morphological measures. Subcortical volume was lower in the basal ganglia and the hippocampus in WS versus TD controls. Exploratory correlations revealed that anxiety scores were negatively correlated with gray matter surface area in insula, OFC, rostral middle frontal, superior temporal and lingual gyrus. Our results were consistent with previous reports showing structural alterations in regions supporting the socio-affective and visuospatial impairments in WS. However, we also were able to effectively capture novel and complex

  2. Regional brain differences in cortical thickness, surface area and subcortical volume in individuals with Williams syndrome.

    Directory of Open Access Journals (Sweden)

    Shashwath A Meda

    Full Text Available Williams syndrome (WS is a rare genetic neurodevelopmental disorder characterized by increased non-social anxiety, sensitivity to sounds and hypersociability. Previous studies have reported contradictory findings with regard to regional brain variation in WS, relying on only one type of morphological measure (usually volume in each study. The present study aims to contribute to this body of literature and perhaps elucidate some of these discrepancies by examining concurrent measures of cortical thickness, surface area and subcortical volume between WS subjects and typically-developing (TD controls. High resolution MRI scans were obtained on 31 WS subjects and 50 typically developing control subjects. We derived quantitative regional estimates of cortical thickness, cortical surface area, and subcortical volume using FreeSurfer software. We evaluated between-group ROI differences while controlling for total intracranial volume. In post-hoc exploratory analyses within the WS group, we tested for correlations between regional brain variation and Beck Anxiety Inventory scores. Consistent with our hypothesis, we detected complex patterns of between-group cortical variation, which included lower surface area in combination with greater thickness in the following cortical regions: post central gyrus, cuneus, lateral orbitofrontal cortex and lingual gyrus. Additional cortical regions showed between-group differences in one (but not both morphological measures. Subcortical volume was lower in the basal ganglia and the hippocampus in WS versus TD controls. Exploratory correlations revealed that anxiety scores were negatively correlated with gray matter surface area in insula, OFC, rostral middle frontal, superior temporal and lingual gyrus. Our results were consistent with previous reports showing structural alterations in regions supporting the socio-affective and visuospatial impairments in WS. However, we also were able to effectively capture novel and

  3. Multifractal spectrums for volumes of spatial forms on surface of ZnxCd1-xTe-Si (111) heterostructures and estimation of the fractal surface energy

    Science.gov (United States)

    Moskvin, Pavel; Kryzhanivskyy, Vyacheslav; Lytvyn, Petro; Rashkovetskyi, Liubomyr

    2016-09-01

    Multifractal (MF) analysis is used to describe volumes of spatial forms that are formed on the surface of thin layers of ZnxCd1-xTe solid solution grown on the Si (111) substrate. MF analysis is performed on the basis of AFM images of the solid solution surface. The parameters of the MF spectrums for the distribution of volumes of the spatial forms, which formed the surface relief, were found. On the basis of a formal approach and data on the multifractal parameters for the volume and the area of the surface spatial forms the mathematic expression which takes into account the contribution of the fractal surface structure in its surface energy were proposed. The behavior of the surface energy of the system depending on the fractal parameters that describe the volume and the area of the spatial forms on the fractal surface were discussed.

  4. New Series of Soil Samplers and Their Application

    Institute of Scientific and Technical Information of China (English)

    JIASHU-GANG; YANGXUE-MING; 等

    1995-01-01

    In this paper,the structure of “double juts” soil sampler and a series of new soil samplers are introduced.The internal diameter of auger tip the sampler is less than that of sampling tube.but the external diameter of auger tip is larger than that of sampling tube,Therefore,adhesion and cutting resistance can be reduced by limiting conncetion areas between sampler and the soil,Such a new structure makes if possible to be widely used for the production of a series of special soil samplers.

  5. Internal photoemission from plasmonic nanoparticles: comparison between surface and volume photoelectric effects

    DEFF Research Database (Denmark)

    Uskov, Alexander; Protsenko, Igor E.; Ikhsanov, Renat S.;

    2014-01-01

    We study the emission of photoelectrons from plasmonic nanoparticles into a surrounding matrix. We consider two mechanisms of electron emission from the nanoparticles - surface and volume ones and use models for these two mechanisms which allow us to obtain analytical results for the photoelectro...... to take both mechanisms into account in the development of devices based on the photoelectric effect and when considering hot electron emission from a plasmonic nanoantenna....... emission rate from a nanoparticle. Calculations have been carried out for a step potential at the surface of a spherical nanoparticle, and a simple model for the hot electron cooling has been used. We highlight the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary....... In accordance with our calculations, this possible predominance of the surface effect is based on two factors: (i) effective cooling of hot carriers during their propagation from the volume of the nanoparticle to its surface in the scenario of the volume mechanism and (ii) strengthening of the surface mechanism...

  6. Cortical Thickness, Surface Area and Subcortical Volume Differentially Contribute to Cognitive Heterogeneity in Parkinson's Disease.

    Directory of Open Access Journals (Sweden)

    Niels J H M Gerrits

    Full Text Available Parkinson's disease (PD is often associated with cognitive deficits, although their severity varies considerably between patients. Recently, we used voxel-based morphometry (VBM to show that individual differences in gray matter (GM volume relate to cognitive heterogeneity in PD. VBM does, however, not differentiate between cortical thickness (CTh and surface area (SA, which might be independently affected in PD. We therefore re-analyzed our cohort using the surface-based method FreeSurfer, and investigated (i CTh, SA, and (subcortical GM volume differences between 93 PD patients and 45 matched controls, and (ii the relation between these structural measures and cognitive performance on six neuropsychological tasks within the PD group. We found cortical thinning in PD patients in the left pericalcarine gyrus, extending to cuneus, precuneus and lingual areas and left inferior parietal cortex, bilateral rostral middle frontal cortex, and right cuneus, and increased cortical surface area in the left pars triangularis. Within the PD group, we found negative correlations between (i CTh of occipital areas and performance on a verbal memory task, (ii SA and volume of the frontal cortex and visuospatial memory performance, and, (iii volume of the right thalamus and scores on two verbal fluency tasks. Our primary findings illustrate that i CTh and SA are differentially affected in PD, and ii VBM and FreeSurfer yield non-overlapping results in an identical dataset. We argue that this discrepancy is due to technical differences and the subtlety of the PD-related structural changes.

  7. Modification of the Steel Surface Treated by a Volume Discharge Plasma in Nitrogen at Atmospheric Pressure

    Science.gov (United States)

    Erofeev, M. V.; Shulepov, M. A.; Ivanov, Yu. F.; Oskomov, K. V.; Tarasenko, V. F.

    2016-03-01

    Effect of volume discharge plasma initiated by an avalanche electron beam on the composition, structure, and properties of the surface steel layer is investigated. Voltage pulses with incident wave amplitude up to 30 kV, full width at half maximum of about 4 ns, and wave front of about 2.5 ns were applied to the gap with an inhomogeneous electric field. Changes indicating the hardening effect of the volume discharge initiated by an avalanche electron beam are revealed in St3-grade steel specimens treated by the discharge of this type.

  8. Estimation of surface area and pore volume of activated carbons by methylene blue and iodine numbers

    Directory of Open Access Journals (Sweden)

    Cleiton A. Nunes

    2011-01-01

    Full Text Available Data of methylene blue number and iodine number of activated carbons samples were calibrated against the respective surface area, micropore volume and total pore volume using multiple regression. The models obtained from the calibrations were used in predicting these physical properties of a test group of activated carbon samples produced from several raw materials. In all cases, the predicted values were in good agreement with the expected values. The method allows extracting more information from the methylene blue and iodine adsorption studies than normally obtained with this type of material.

  9. NEW SOIL VOC SAMPLERS: EN CORE AND ACCU CORE SAMPLING/STORAGE DEVICES FOR VOC ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Susan S. Sorini; John F. Schabron; Joseph F. Rovani Jr

    2006-06-01

    Soil sampling and storage practices for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from samples. The En Core{reg_sign} sampler is designed to collect and store soil samples in a manner that minimizes loss of contaminants due to volatilization and/or biodegradation. An ASTM International (ASTM) standard practice, D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, describes use of the En Core sampler to collect and store a soil sample of approximately 5 grams or 25 grams for volatile organic analysis and specifies sample storage in the En Core sampler at 4 {+-} 2 C for up to 48 hours; -7 to -21 C for up to 14 days; or 4 {+-} 2 C for up to 48 hours followed by storage at -7 to -21 C for up to five days. This report discusses activities performed during the past year to promote and continue acceptance of the En Core samplers based on their performance to store soil samples for VOC analysis. The En Core sampler is designed to collect soil samples for VOC analysis at the soil surface. To date, a sampling tool for collecting and storing subsurface soil samples for VOC analysis is not available. Development of a subsurface VOC sampling/storage device was initiated in 1999. This device, which is called the Accu Core{trademark} sampler, is designed so that a soil sample can be collected below the surface using a dual-tube penetrometer and transported to the laboratory for analysis in the same container. Laboratory testing of the current Accu Core design shows that the device holds low-level concentrations of VOCs in soil samples during 48-hour storage at 4 {+-} 2 C and that the device is ready for field evaluation to generate additional performance data. This report discusses a field validation exercise that was attempted in Pennsylvania in 2004 and activities being performed to plan and conduct a field validation study in 2006. A draft ASTM

  10. Deep Near-Infrared Surface Photometry and Properties of Local Volume Dwarf Irregular Galaxies

    CERN Document Server

    Young, T; López-Sánchez, Á R; Koribalski, B S

    2014-01-01

    We present deep H-band surface photometry and analysis of 40 Local Volume galaxies, a sample primarily composed of dwarf irregulars in the Cen A group, obtained using the IRIS2 detector at the 3.9m Anglo-Australian Telescope. We probe to a surface brightness of ~25 mag arcsec$^{-2}$, reaching a 40 times lower stellar density than the Two Micron All Sky Survey (2MASS). Employing extremely careful and rigorous cleaning techniques to remove contaminating sources, we perform surface photometry on 33 detected galaxies deriving the observed total magnitude, effective surface brightness and best fitting S\\'ersic parameters. We make image quality and surface photometry comparisons to 2MASS and VISTA Hemispheric Survey (VHS) demonstrating that deep targeted surveys are still the most reliable means of obtaining accurate surface photometry. We investigate the B-H colours with respect to mass for Local Volume galaxies, finding that the colours of dwarf irregulars are significantly varied, eliminating the possibility of ...

  11. Variation in the measurement of cranial volume and surface area using 3D laser scanning technology.

    Science.gov (United States)

    Sholts, Sabrina B; Wärmländer, Sebastian K T S; Flores, Louise M; Miller, Kevin W P; Walker, Phillip L

    2010-07-01

    Three-dimensional (3D) laser scanner models of human crania can be used for forensic facial reconstruction, and for obtaining craniometric data useful for estimating age, sex, and population affinity of unidentified human remains. However, the use of computer-generated measurements in a casework setting requires the measurement precision to be known. Here, we assess the repeatability and precision of cranial volume and surface area measurements using 3D laser scanner models created by different operators using different protocols for collecting and processing data. We report intraobserver measurement errors of 0.2% and interobserver errors of 2% of the total area and volume values, suggesting that observer-related errors do not pose major obstacles for sharing, combining, or comparing such measurements. Nevertheless, as no standardized procedure exists for area or volume measurements from 3D models, it is imperative to report the scanning and postscanning protocols employed when such measurements are conducted in a forensic setting.

  12. Capillary Forces between Submillimeter Spheres and Flat Surfaces at Constant Liquid Volumes

    Institute of Scientific and Technical Information of China (English)

    WANG Le-Feng; RONG Wei-Bin; SUN Li-Ning; CHEN Li-Guo; SHAO Bing

    2009-01-01

    We investigate the capillary forces between submillimeter spheres and flat surfaces at constant liquid volumes theoretically and experimentally.An iterative method is used to estimate the capillary force with contact angles as the boundary conditions and the constant volume as a constraint.The theoretical analysis shows that the maximum capillary force between them decreases with the increase of the liquid bridge volume at small contact angles.The experimental results show that the force is smaller than the theoretical values at the initial separation distances.It is also observed that the force first increases and then decreases with an increasing separation distance in some cases.These phenomena of capillary forces hysteresis are explained according to the wetting hysteresis.

  13. A novel method for the in situ calibration of flow effects on a phosphate passive sampler.

    Science.gov (United States)

    Sara O'Brien, Dominique; Chiswell, Barry; Mueller, Jochen F

    2009-01-01

    Monitoring of nutrients including phosphate in the aquatic environment remains a challenge. In the last decade passive sampling techniques have been developed that facilitates the time integrated monitoring of phosphate (P) through the use of an iron hydroxide (ferrihydrite) to sequester dissolved phosphate from solution. These methods rely on established techniques to negate the effects of flow (and associated turbulence) and control the rate at which chemicals accumulate within passive samplers. In this study we present a phosphate sampler within which a suspension of ferrihydrite is contained behind a commercially available membrane. Accumulation of dissolved phosphates into the P-sampler is governed by the rate at which ions are diffusing through the membrane and the water boundary layer (WBL). As the WBL changes subject to flow we have adopted an in situ calibration technique based on the dissolution of gypsum to predict the change in the rate of uptake dependent on flow. Here we demonstrate that the loss of gypsum from the passive flow monitor (PFM) can be used to predict the sampling rate (the volume of water extracted per day) for phosphate as a function of water velocity. The outcome of this study presents a new in-field tool for more accurate prediction of the effect of flow/turbulence on the uptake kinetics into passive samplers that is controlled by the diffusion of the chemical of interest through the stagnant water boundary layer.

  14. An Electric Field Volume Integral Equation Approach to Simulate Surface Plasmon Polaritons

    Directory of Open Access Journals (Sweden)

    R. Remis

    2013-02-01

    Full Text Available In this paper we present an electric field volume integral equation approach to simulate surface plasmon propagation along metal/dielectric interfaces. Metallic objects embedded in homogeneous dielectric media are considered. Starting point is a so-called weak-form of the electric field integral equation. This form is discretized on a uniform tensor-product grid resulting in a system matrix whose action on a vector can be computed via the fast Fourier transform. The GMRES iterative solver is used to solve the discretized set of equations and numerical examples, illustrating surface plasmon propagation, are presented. The convergence rate of GMRES is discussed in terms of the spectrum of the system matrix and through numerical experiments we show how the eigenvalues of the discretized volume scattering operator are related to plasmon propagation and the medium parameters of a metallic object.

  15. MaterialVis: material visualization tool using direct volume and surface rendering techniques.

    Science.gov (United States)

    Okuyan, Erhan; Güdükbay, Uğur; Bulutay, Ceyhun; Heinig, Karl-Heinz

    2014-05-01

    Visualization of the materials is an indispensable part of their structural analysis. We developed a visualization tool for amorphous as well as crystalline structures, called MaterialVis. Unlike the existing tools, MaterialVis represents material structures as a volume and a surface manifold, in addition to plain atomic coordinates. Both amorphous and crystalline structures exhibit topological features as well as various defects. MaterialVis provides a wide range of functionality to visualize such topological structures and crystal defects interactively. Direct volume rendering techniques are used to visualize the volumetric features of materials, such as crystal defects, which are responsible for the distinct fingerprints of a specific sample. In addition, the tool provides surface visualization to extract hidden topological features within the material. Together with the rich set of parameters and options to control the visualization, MaterialVis allows users to visualize various aspects of materials very efficiently as generated by modern analytical techniques such as the Atom Probe Tomography.

  16. A Calderón multiplicative preconditioner for coupled surface-volume electric field integral equations

    KAUST Repository

    Bagci, Hakan

    2010-08-01

    A well-conditioned coupled set of surface (S) and volume (V) electric field integral equations (S-EFIE and V-EFIE) for analyzing wave interactions with densely discretized composite structures is presented. Whereas the V-EFIE operator is well-posed even when applied to densely discretized volumes, a classically formulated S-EFIE operator is ill-posed when applied to densely discretized surfaces. This renders the discretized coupled S-EFIE and V-EFIE system ill-conditioned, and its iterative solution inefficient or even impossible. The proposed scheme regularizes the coupled set of S-EFIE and V-EFIE using a Calderón multiplicative preconditioner (CMP)-based technique. The resulting scheme enables the efficient analysis of electromagnetic interactions with composite structures containing fine/subwavelength geometric features. Numerical examples demonstrate the efficiency of the proposed scheme. © 2006 IEEE.

  17. Comparison of aerosol volume size distributions between column and surface measurements downwind of Seoul, Korea

    Science.gov (United States)

    Park, J. S.; Choi, Y.; Ghim, Y. S.

    2015-12-01

    The aerosol volume size distribution is one of the most important parameters in retrieving aerosol optical properties and studying radiative forcing. The column-integrated aerosol volume size distribution for AERONET was obtained from inversion product level 1.5 (22 bins between 0.1 and 30 μm in diameter) from the measurements of CIMEL sunphotometer (CE-318); that for SKYNET was obtained using skyrad.pack V5 (20 bins, 0.02-33 μm) from the measurements of PREDE skyradiometer (POM-02). The aerosol volume size distribution at the surface was measured using a wide range aerosol spectrometer system consisting of a scanning mobility particle scanner (Grimm, Model 5.419; 89 bins, 0.005-0.35 μm) and an optical particle counter (Grimm, Model 1.109; 31 bins, 0.27-34 μm). The measurement was conducted in Yongin, downwind of Seoul, Korea, from April 30 to June 27, 2015. The measurement site is located on the rooftop of a five-story building on the hill (37.34°N, 127.27°E, 167 m above sea level) in the global campus of Hankuk University of Foreign Studies. To investigate the discrepancy in effective diameter and fine mode volume fraction, we compared the volume size distributions when the measurement time coincided within 5 minutes because the measurement intervals were different between instruments.

  18. A posteriori error estimates for finite volume approximations of elliptic equations on general surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Lili; Tian, Li; Wang, Desheng

    2008-10-31

    In this paper, we present a residual-based a posteriori error estimate for the finite volume discretization of steady convection– diffusion–reaction equations defined on surfaces in R3, which are often implicitly represented as level sets of smooth functions. Reliability and efficiency of the proposed a posteriori error estimator are rigorously proved. Numerical experiments are also conducted to verify the theoretical results and demonstrate the robustness of the error estimator.

  19. Dynamics at Solid State Surfaces and Interfaces, Volume 1 Current Developments

    CERN Document Server

    Bovensiepen, Uwe; Wolf, Martin

    2010-01-01

    This two-volume work covers ultrafast structural and electronic dynamics of elementary processes at solid surfaces and interfaces, presenting the current status of photoinduced processes. Providing valuable introductory information for newcomers to this booming field of research, it investigates concepts and experiments, femtosecond and attosecond time-resolved methods, as well as frequency domain techniques. The whole is rounded off by a look at future developments.

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

    Science.gov (United States)

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

    2012-07-01

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

  1. CAM and stack air sampler design guide

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, T.D.

    1994-05-13

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

  2. Effect of sessile drop volume on the wetting anisotropy observed on grooved surfaces.

    Science.gov (United States)

    Yang, Jing; Rose, Felicity R A J; Gadegaard, Nikolaj; Alexander, Morgan R

    2009-03-03

    This study reports experimental measurements of the water contact angle (WCA) measured on surfaces with grooves of different widths using drop volumes ranging from 400 pL to 4.5 microL. These measurements were carried out on both relatively hydrophobic and hydrophilic surface chemistry formed using a conformal plasma polymer coating of topographically embossed poly(methyl methacrylate) (PMMA). Anisotropic wetting of the grooved surfaces was found to be more marked for larger drops on both the hydrophilic and hydrophobic surfaces. Above a certain drop base diameter to groove width ratio, topography had no effect on the measured WCA; this ratio was found to be dependent on the water drop volume. The WCA measured from the direction perpendicular to the grooves using submicroliter water drops is found to be a good indicator of the WCA on the flat surface with equivalent wettabilities. To the best of our knowledge, this is the first study on the phenomenon of anisotropic wetting using picoliter water drops.

  3. Formed Core Sampler Hydraulic Conductivity Testing

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-25

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

  4. A Comparison of Silicone-coated Paper Samplers and Polyethylene in Narragansett Bay

    Science.gov (United States)

    Dekany, V.; Lohmann, R.

    2008-12-01

    Accurately measuring dissolved concentrations of persistent organic pollutants (POPs) in surface waters remains a major challenge due to low concentrations, contamination concerns and sampling artifacts, such as sorption to dissolved organic carbon (DOC). Knowing dissolved concentrations of POPs, such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), is key to understanding their fate in the ocean and their accumulation in the food-chain. The affinity of POPs towards hydrophobic matrices can be used to absorb the species of interest from their environment, a method known as passive sampling. As passive sampling devices (PSDs) rely on passive diffusion to accumulate analytes of interest, it is critical to better understand whether and when equilibrium has been achieved during field deployments. Silicone-based paper (41 g/m2 cellulose, 0.45-0.5 g Si/m2/side) and polyethylene samplers (PEs; 25 μm thickness) were compared in Narragansett Bay in July 2008. Samplers were deployed for 2, 4 and 8 days to derive [PAHs] in the water column. The effectiveness of each passive sampler was based on (i) the percent of performance reference compounds (PRCs) remaining in the device, (ii) the sorption capacity of the PSD for POPs, and (iii) successful field deployments in the Narragansett Bay water column. Samplers were analyzed for PAHs and PRCs (d-anthracene, d-benz[a]anthracene, and d-benzo[a]pyrene) by gas chromatography/mass spectrometry. As expected, faster loss rates were observed for lower molecular weight PRCs in both sampler types. The silicone paper samplers displayed faster equilibrium times than the PE samplers. The observed [PAHs] in the passive samplers were corrected for the temperature and salinity of the Bay water. The PRC loss rates were used to correct for non-equilibrium concentrations. Lastly, dissolved [PAHs] were calculated based on published PE-water equilibrium partitioning constants. Dissolved concentrations of PAHs derived

  5. Prediction of lateral surface, volume and sphericity of pomegranate using MLP artificial neural network

    Directory of Open Access Journals (Sweden)

    A Rohani

    2015-09-01

    Full Text Available Introduction: Fast and accurate determination of geometrical properties of agricultural products has many applications in agricultural operations like planting, cultivating, harvesting and post-harvesting. Calculations related to storing, shipping and storage-coating materials as well as peeling time and surface-microbial concentrations are some applications of estimating product volume and surface area. Sphericity is also a parameter by which the shape differences between fruits, vegetables, grains and seeds can be quantified. This parameter is important in grading systems and inspecting rolling capability of agricultural products. Bayram presented a new dimensional method and equation to calculate the sphericity of certain shapesand some granular food materials (Bayram, 2005. Kumar and Mathew proposed atheoretically soundmethod for estimating the surface area of ellipsoidal food materials (Kumar and Mathew, 2003. Clayton et al. used non-linear regression models for calculation of apple surface area using the fruit mass or volume (Clayton et al., 1995. Humeida and Hobani predicted surface area and volume of pomegranates based on the weight and geometrical diametermean (Humeida and Hobani, 1993. Wang and Nguang designeda low cost sensor system to automatically compute the volume and surface area of axi-symmetricagricultural products such as eggs, lemons, limes and tamarillos (Wang and Nguang, 2007. The main objective of this study was to investigate the potential of Artificial Neural Network (ANN technique as an alternative method to predict the volume, surface area and sphericity of pomegranates. Materials and methods: The water displacement method (WDM was used for measuring the actual volume of pomegranates. Also, the sphericity and surface area are computed by using analytical methods. In this study, the neural MLP models were designed based upon the three nominal diameters of pomegranatesas variable inputs, while the output model consisted

  6. Formation of superpower volume discharges and their application for modification of surface of metals

    Science.gov (United States)

    Tarasenko, Victor F.; Shulepov, M. A.

    2008-05-01

    The results of experimental investigations of a volume avalanche discharge initiated by an e-beam (VADIEB) and surface layer of Cu and AlBe foils modifications at the plasma action of VADIEB are given. The volume discharge in the air of atmosphere pressure formed in the gap with the cathode having small curvature radius and with high voltage pulses of nanosecond duration and positive and negative polarity. A supershort avalanche electron beam (SAEB) with formation conditions in gases under atmospheric pressure have been investigated. It is proved that the surface layer is cleared of carbon at foil treatment, and atoms of oxygen penetrate into a foil. It is show that the cleaning depth depends on polarity of voltage pulses. At positive polarity of a copper foil electrode the cleaning is observed at the depth over 50 nm, and atoms of oxygen penetrate at the depth up to 25 nm. Plasma of the superpower volume discharge of nanosecond duration with a specific excitation power of hundreds of MW/cm3, and SAEB, and the discharge plasma radiation of various spectral ranges (including UV, VUV and X-ray) has the influence on the anode. The supershort avalanche electronic beam is generated only at negative polarity of a voltage pulse on an electrode with a small radius of curvature. SAEB influence on modifications of the copper foil surface is registered. VADIEB is easily realized in various gases and at various pressures, and, at gas pressure decrease the density of the beam current in helium can achieve 2 kA/cm2. It allows predicting an opportunity of VADIEB application for metal surface modifications in various technological processes, and for surface dielectric modifications at the certain design of the anode.

  7. Density, Molar Volume, and Surface Tension of Liquid Al-Ti

    Science.gov (United States)

    Wessing, Johanna Jeanette; Brillo, Jürgen

    2017-02-01

    Al-Ti-based alloys are of enormous technical relevance due to their specific properties. For studies in atomic dynamics, surface physics and industrial processing the precise knowledge of the thermophysical properties of the liquid phase is crucial. In the present work, we systematically measure mass density, ρ (g cm-3), and the surface tension, γ (N m-1), as functions of temperature, T, and compositions of binary Al-Ti melts. Electromagnetic levitation in combination with the optical dilatometry method is used for density measurements and the oscillating drop method for surface tension measurements. It is found that, for all compositions, density and surface tension increase linearly upon decreasing temperature in the liquid phase. Within the Al-Ti system, we find the largest values for pure titanium and the smallest for pure aluminum, which amount to ρ(L,Ti) = 4.12 ± 0.04 g cm-3 and γ(L,Ti) = 1.56 ± 0.02 N m-1; and ρ(L,Al) = 2.09 ± 0.01 g cm-3 and γ(L,Al) = 0.87 ± 0.06 N m-1, respectively. The data are analyzed concerning the temperature coefficients, ρ T and γ T, excess molar volume, V E, excess surface tension, γ E, and surface segregation of the surface active component, Al. The results are compared with thermodynamic models. Generally, it is found that Al-Ti is a highly nonideal system.

  8. Particle capturing performance of South African non corrosive samplers

    CSIR Research Space (South Africa)

    Pretorius, C

    2010-05-01

    Full Text Available samplers (also known as cyclones) Particle-capturing performance of South African non-corrosive samplers © CSIR 2007 www.csir.co.za Objectives: • To compare the performance of two locally manufactured samplers with one another... = 90% of the sample has a particle size below this value © CSIR 2007 www.csir.co.za Particle size distribution of sampled dust • Respirable dust is defined as particulate passing through a cyclone with an efficiency...

  9. Boltzmann Samplers for v-balanced Colored Necklaces

    CERN Document Server

    Bodini, Olivier

    2009-01-01

    This paper is devoted to the random generation of particular colored necklaces for which the number of beads of a given color is constrained (these necklaces are called v-balanced). We propose an efficient sampler (its expected time complexity is linear) which satisfies the Boltzmann model principle introduced by Duchon, Flajolet, Louchard and Schaeffer. Our main motivation is to show that the absence of a decomposable specification can be circumvented by mixing the Boltzmann samplers with other types of samplers.

  10. New model for estimating the relationship between surface area and volume in the human body using skeletal remains.

    Science.gov (United States)

    Kasabova, Boryana E; Holliday, Trenton W

    2015-04-01

    A new model for estimating human body surface area and body volume/mass from standard skeletal metrics is presented. This model is then tested against both 1) "independently estimated" body surface areas and "independently estimated" body volume/mass (both derived from anthropometric data) and 2) the cylindrical model of Ruff. The model is found to be more accurate in estimating both body surface area and body volume/mass than the cylindrical model, but it is more accurate in estimating body surface area than it is for estimating body volume/mass (as reflected by the standard error of the estimate when "independently estimated" surface area or volume/mass is regressed on estimates derived from the present model). Two practical applications of the model are tested. In the first test, the relative contribution of the limbs versus the trunk to the body's volume and surface area is compared between "heat-adapted" and "cold-adapted" populations. As expected, the "cold-adapted" group has significantly more of its body surface area and volume in its trunk than does the "heat-adapted" group. In the second test, we evaluate the effect of variation in bi-iliac breadth, elongated or foreshortened limbs, and differences in crural index on the body's surface area to volume ratio (SA:V). Results indicate that the effects of bi-iliac breadth on SA:V are substantial, while those of limb lengths and (especially) the crural index are minor, which suggests that factors other than surface area relative to volume are driving morphological variation and ecogeographical patterning in limb prorportions.

  11. Microwave detection of surface and volume moisture in building walls and related structures

    Science.gov (United States)

    Bastida, E. M.; Ricca, A. M.

    Microwave technique for non-contacting volume and surface moisture measurements in concrete and building walls is described. The reflection and attenuation coefficients of an electromagnetic wave, in the microwave spectrum region, impinging upon a humid wall are studied. Reflection and attenuation are related to the water content. The attenuation coefficient is related to the space-average humidity, while reflection measurements depend also on the humidity profile. By means of a computer simulation surface humidity and surface humidity gradient are both measured by reflectometric techniques. Combining reflection and attenuation measurements, information about the humidity profile is obtained in a non-contacting way. Experimental results on reflection and attenuation measurements are also presented.

  12. Excitation of surface and volume plasmons in metal nanocluster by fast electrons

    CERN Document Server

    Gildenburg, V B; Pavlichenko, I A

    2015-01-01

    Surface and volume plasmons excited in a metal cluster by moving electron and corresponding inelastic scattering spectra are studied based on the hydrodynamic approach. Along with the bulk losses traditionally taken into account, the surface and radiative ones are also considered as the physical mechanisms responsible for the plasmon damping. The second and third mechanisms are found to be essential for the surface plasmons and depend very differently on the multipole mode order. The differential equations are obtained which describe the temporal evolution of every particular mode as that one of a linear oscillator excited by the given external force, and the electron energy loss spectra are calculated. The changes in spectrum shape with the impact parameter and with the electron passage time are analyzed and found to be in good enough agreement with the data of scanning transmission electron microscopy (STEM) experiments. It is shown that, in the general case, a pronounced contribution to the formation of th...

  13. Method for combining fast surface and exact volume visualization techniques in medicine

    Science.gov (United States)

    Englmeier, Karl-Hans; Haubner, Michael; Foerterer, H. M.; Perzl, W.; Fink, B. K.; Fink, U.

    1994-05-01

    In order to enable the interaction with and manipulation of 3-D data sets in the realm of medical diagnosis and therapy planning we developed a modified Z-merging algorithm that includes transparency and texture mapping features. For this an extended shape based interpolation model creates isotropic grayscale data volume in case of spatial image sequences. Interesting anatomical regions such as soft tissue, organs, and bones are detected by automatic and interactive segmentation procedures. Following that, a fully automatic surface construction algorithm detects the 3-D object boundaries by fitting geometric primitives to the binary data. The surface representations support the user with a fast overview about the structure of the 3D scene. Texture mapping is implemented as the projection of the gray values of the isotropic voxels onto a polygonal surface. Adaptive refinement, Phong's normal interpolation, and transparency are the most important features of this raytracer. The described technique enables the simultaneous display of multimodal 3D image data.

  14. Left ventricle endocardium segmentation for cardiac CT volumes using an optimal smooth surface

    Science.gov (United States)

    Zheng, Yefeng; Georgescu, Bogdan; Vega-Higuera, Fernando; Comaniciu, Dorin

    2009-02-01

    We recently proposed a robust heart chamber segmentation approach based on marginal space learning. In this paper, we focus on improving the LV endocardium segmentation accuracy by searching for an optimal smooth mesh that tightly encloses the whole blood pool. The refinement procedure is formulated as an optimization problem: maximizing the surface smoothness under the tightness constraint. The formulation is a convex quadratic programming problem, therefore has a unique global optimum and can be solved efficiently. Our approach has been validated on the largest cardiac CT dataset (457 volumes from 186 patients) ever reported. Compared to our previous work, it reduces the mean point-to-mesh error from 1.13 mm to 0.84 mm (22% improvement). Additionally, the system has been extensively tested on a dataset with 2000+ volumes without any major failure.

  15. Coupling of Surface and Volume Dipole Oscillations in C-60 Molecules

    CERN Document Server

    Brack, M; Murthy, M V N

    2007-01-01

    We first give a short review of the ``local-current approximation'' (LCA), derived from a general variation principle, which serves as a semiclassical description of strongly collective excitations in finite fermion systems starting from their quantum-mechanical mean-field ground state. We illustrate it for the example of coupled translational and compressional dipole excitations in metal clusters. We then discuss collective electronic dipole excitations in C$_{60}$ molecules (Buckminster fullerenes). We show that the coupling of the pure translational mode (``surface plasmon'') with compressional volume modes in the semiclasscial LCA yields semi-quantitative agreement with microscopic time-dependent density functional (TDLDA) calculations, while both theories yield qualitative agreement with the recent experimental observation of a ``volume plasmon''.

  16. High-voltage electrode optimization towards uniform surface treatment by a pulsed volume discharge

    Science.gov (United States)

    Ponomarev, A. V.; Pedos, M. S.; Scherbinin, S. V.; Mamontov, Y. I.; Ponomarev, S. V.

    2015-11-01

    In this study, the shape and material of the high-voltage electrode of an atmospheric pressure plasma generation system were optimised. The research was performed with the goal of achieving maximum uniformity of plasma treatment of the surface of the low-voltage electrode with a diameter of 100 mm. In order to generate low-temperature plasma with the volume of roughly 1 cubic decimetre, a pulsed volume discharge was used initiated with a corona discharge. The uniformity of the plasma in the region of the low-voltage electrode was assessed using a system for measuring the distribution of discharge current density. The system's low-voltage electrode - collector - was a disc of 100 mm in diameter, the conducting surface of which was divided into 64 radially located segments of equal surface area. The current at each segment was registered by a high-speed measuring system controlled by an ARM™-based 32-bit microcontroller. To facilitate the interpretation of results obtained, a computer program was developed to visualise the results. The program provides a 3D image of the current density distribution on the surface of the low-voltage electrode. Based on the results obtained an optimum shape for a high-voltage electrode was determined. Uniformity of the distribution of discharge current density in relation to distance between electrodes was studied. It was proven that the level of non-uniformity of current density distribution depends on the size of the gap between electrodes. Experiments indicated that it is advantageous to use graphite felt VGN-6 (Russian abbreviation) as the material of the high-voltage electrode's emitting surface.

  17. Nasal Drug Absorption from Powder Formulations: Effect of Fluid Volume Changes on the Mucosal Surface.

    Science.gov (United States)

    Tanaka, Akiko; Furubayashi, Tomoyuki; Enomura, Yuki; Hori, Tomoki; Shimomura, Rina; Maeda, Chiaki; Kimura, Shunsuke; Inoue, Daisuke; Kusamori, Kosuke; Katsumi, Hidemasa; Sakane, Toshiyasu; Yamamoto, Akira

    2017-01-01

    The effect of changes in the mucosal fluid volume on the nasal drug absorption of powder formulations was evaluated using warfarin (WF), piroxicam (PXC), and norfloxacin (NFX) as model drugs. Lactose and sodium chloride (NaCl), which are water soluble and small-sized chemicals that increase osmotic pressure after dissolution, were used as excipients to change the mucosal fluid volume. The in vitro study using a Madin-Darby canine kidney (MDCK) cell monolayer indicated that lactose and NaCl, sprayed over the surface of air interface monolayers, increased the fluid volume on the monolayer surface and enhanced the transepithelial transport of the model drugs. The in vivo animal study indicated that the nasal absorption of PXC is enhanced by lactose and NaCl after nasal administration of the powder formulations. This is likely due to the enhanced dissolution of PXC on fluid-rich nasal mucosa and an increase in the effective surface area for drug permeation, which lead to better nasal absorption. However, both excipients failed to increase the nasal absorption of WF and NFX. To clarify the mechanism of the drug-dependent effect of lactose and NaCl, the nasal residence of the formulation was examined using FD70 as a non-absorbable marker. The nasal clearance of FD70 was enhanced by lactose and NaCl, leading to a decrease in the nasal drug absorption. Lactose and NaCl caused no damage to the nasal tissue. These results indicate that the addition of water-soluble excipients such as lactose to powder formulations can enhance the nasal absorption of highly permeable but poorly soluble drugs.

  18. Solution of volume-surface integral equations using higher-order hierarchical Legendre basis functions

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Meincke, Peter; Breinbjerg, Olav

    2007-01-01

    is applied to transform the VSIE into a system of linear equations. The higher-order MoM provides significant reduction in the number of unknowns in comparison with standard MoM formulations using low-order basis functions, such as RWG functions. Due to the orthogonal nature of the higher-order Legendre......The problem of electromagnetic scattering by composite metallic and dielectric objects is solved using the coupled volume-surface integral equation (VSIE). The method of moments (MoM) based on higher-order hierarchical Legendre basis functions and higher-order curvilinear geometrical elements...

  19. Understanding the growth mechanism of carbon nanotubes via the ``cluster volume to surface area" model

    Science.gov (United States)

    Mandati, Sreekanth; Kunstmann, Jens; Boerrnert, Felix; Schoenfelder, Ronny; Ruemmeli, Mark; Kar, Kamal K.; Cuniberti, Gianaurelio

    2010-03-01

    The influence of mixed catalysts for the high yield production of carbon nanotubes (CNTs) has been studied systematically. Based on extensive experimental data a ``Catalyst Volume to Surface Area'' (CVSA) model was developed to understand the influence of the process parameters on the yield and CNT diameter distribution [1]. In our study, we present a refined version of the CVSA model developed by combining experiments and simulations. We discuss our current understanding of the growth mechanism and how the model might be used to increase CNT yields by using mixed catalysts.[4pt] [1] S. Tetali et al., ACS Nano (2009), DOI: 10.1021/nn9012548.

  20. Surface area and volume measurements of volcanic ash particles by SEM stereoscopic imaging

    Science.gov (United States)

    Ersoy, Orkun

    2010-05-01

    Surface area of volcanic ash particles is of great importance to research including plume dynamics, particle chemical and water reactions in the plume, modelling (i.e. plume shape, particle interactions , dispersion etc.), remote sensing of transport and SO2, HCl, H2O, CO2 levels, forecasting plume location, and transportation and deposition of ash particles. The implemented method presented in this study offer new insights for surface characterization of volcanic ash particles on macro-pore regions. Surface area and volumes of volcanic ash particles were measured using digital elevation models (DEM) reconstructed from stereoscopic images acquired from different angles by scanning electron microscope (SEM). The method was tested using glycidyl methacrylate (GMA) micro-spheres which exhibit low spherical imperfections. The differences between measured and geometrically calculated surface areas were introduced for both micro-spheres and volcanic ash particles in order to highlight the probable errors in modelling on volcanic ash behaviour. The specific surface areas of volcanic ash particles using this method are reduced by half (from mean values of 0.045 m2/g to 0.021 m2/g) for the size increment 63 μm to 125 μm. Ash particles mostly have higher specific surface area values than the geometric forms irrespective of particle size. The specific surface area trends of spheres and ash particles resemble for finer particles (63 μm). Approximation to sphere and ellipsoid have similar margin of error for coarser particles (125 μm) but both seem to be inadequate for representation of real ash surfaces.

  1. Coupling of Smoothed Particle Hydrodynamics with Finite Volume method for free-surface flows

    Science.gov (United States)

    Marrone, S.; Di Mascio, A.; Le Touzé, D.

    2016-04-01

    A new algorithm for the solution of free surface flows with large front deformation and fragmentation is presented. The algorithm is obtained by coupling a classical Finite Volume (FV) approach, that discretizes the Navier-Stokes equations on a block structured Eulerian grid, with an approach based on the Smoothed Particle Hydrodynamics (SPH) method, implemented in a Lagrangian framework. The coupling procedure is formulated in such a way that each solver is applied in the region where its intrinsic characteristics can be exploited in the most efficient and accurate way: the FV solver is used to resolve the bulk flow and the wall regions, whereas the SPH solver is implemented in the free surface region to capture details of the front evolution. The reported results clearly prove that the combined use of the two solvers is convenient from the point of view of both accuracy and computing time.

  2. A model for the volume regulatory mechanism of the Airway Surface Layer

    Science.gov (United States)

    Lang, Michael; Rubinstein, Michael; Davis, C. William; Tarran, Robert; Boucher, Richard

    2006-03-01

    The airway surface layer (ASL) of a lung consists of two parts: a mucus layer with thickness of about 30 μm in contact with air and a periciliary layer (PCL) of about 7 μm below. Mucus collects dust and bacteria and is swept to throat by beating cilia, while riding on top of PCL. It is important that the thickness of PCL is matched with the length of cilia in order to optimize clearance of mucus. Decrease of PCL thickness would finally lead to an occlusion of the respiratory system. Experiments show that the height of PCL stays constant after removing mucus. When modifying height or composition of this open PCL by removing fluid or adding isotonic solution leads to the same final height of PCL. Thus, there must be a regulatory mechanism, that controls height, i.e. ASL volume. Additional experiments show that mechanical stimulus of the cells like shear leads to an increase of ASL volume, thus, the cell is able to actively adjust this volume. Based on these observations a class of models is introduced that describes the experiments and a specific minimum model for the given problem is proposed.

  3. Comparative study of NO removal in surface-plasma and volume-plasma reactors based on pulsed corona discharges.

    Science.gov (United States)

    Malik, Muhammad Arif; Kolb, Juergen F; Sun, Yaohong; Schoenbach, Karl H

    2011-12-15

    Nitric oxide (NO) conversion has been studied for two different types of atmospheric-pressure pulsed-corona discharges, one generates a surface-plasma and the other provides a volume-plasma. For both types of discharges the energy cost for NO removal increases with decreasing oxygen concentration and initial concentration of NO. However, the energy cost for volume plasmas for 50% NO removal, EC(50), from air was found to be 120 eV/molecule, whereas for the surface plasma, it was only 70 eV/molecule. A smaller difference in energy cost, but a higher efficiency for removal of NO was obtained in a pure nitrogen atmosphere, where NO formation is restricted due to the lack of oxygen. For the volume plasma, EC(50) in this case was measured at 50 eV/molecule, and for the surface plasma it was 40 eV/molecule. Besides the higher NO removal efficiency of surface plasmas compared to volume plasmas, the energy efficiency of surface-plasmas was found to be almost independent of the amount of electrical energy deposited in the discharge, whereas the efficiency for volume plasmas decreases considerably with increasing energy. This indicates the possibility of operating surface plasma discharges at high energy densities and in more compact reactors than conventional volume discharges.

  4. Comparative study of NO removal in surface-plasma and volume-plasma reactors based on pulsed corona discharges

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Muhammad Arif, E-mail: MArifMalik@gmail.com [Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA 23508 (United States); Kolb, Juergen F.; Sun, Yaohong; Schoenbach, Karl H. [Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA 23508 (United States)

    2011-12-15

    Nitric oxide (NO) conversion has been studied for two different types of atmospheric-pressure pulsed-corona discharges, one generates a surface-plasma and the other provides a volume-plasma. For both types of discharges the energy cost for NO removal increases with decreasing oxygen concentration and initial concentration of NO. However, the energy cost for volume plasmas for 50% NO removal, EC{sub 50}, from air was found to be 120 eV/molecule, whereas for the surface plasma, it was only 70 eV/molecule. A smaller difference in energy cost, but a higher efficiency for removal of NO was obtained in a pure nitrogen atmosphere, where NO formation is restricted due to the lack of oxygen. For the volume plasma, EC{sub 50} in this case was measured at 50 eV/molecule, and for the surface plasma it was 40 eV/molecule. Besides the higher NO removal efficiency of surface plasmas compared to volume plasmas, the energy efficiency of surface-plasmas was found to be almost independent of the amount of electrical energy deposited in the discharge, whereas the efficiency for volume plasmas decreases considerably with increasing energy. This indicates the possibility of operating surface plasma discharges at high energy densities and in more compact reactors than conventional volume discharges.

  5. Diffusion on a curved surface coupled to diffusion in the volume: Application to cell biology

    Science.gov (United States)

    Novak, Igor L.; Gao, Fei; Choi, Yung-Sze; Resasco, Diana; Schaff, James C.; Slepchenko, Boris M.

    2007-10-01

    An algorithm is presented for solving a diffusion equation on a curved surface coupled to diffusion in the volume, a problem often arising in cell biology. It applies to pixilated surfaces obtained from experimental images and performs at low computational cost. In the method, the Laplace-Beltrami operator is approximated locally by the Laplacian on the tangential plane and then a finite volume discretization scheme based on a Voronoi decomposition is applied. Convergence studies show that mass conservation built in the discretization scheme and cancellation of sampling error ensure convergence of the solution in space with an order between 1 and 2. The method is applied to a cell-biological problem where a signaling molecule, G-protein Rac, cycles between the cytoplasm and cell membrane thus coupling its diffusion in the membrane to that in the cell interior. Simulations on realistic cell geometry are performed to validate, and determine the accuracy of, a recently proposed simplified quantitative analysis of fluorescence loss in photobleaching. The method is implemented within the Virtual Cell computational framework freely accessible at http://www.vcell.org.

  6. 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.

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

    Science.gov (United States)

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

    2014-03-01

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

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

    Science.gov (United States)

    Morrison, Shane A; Belden, Jason B

    2016-06-03

    Environmental exposures often occur through short, pulsed events; therefore, the ability to accurately measure these toxicologically-relevant concentrations is important. Three different integrative passive sampler configurations were evaluated under different flow and pulsed exposure conditions for the measurement of current-use pesticides (n=19), polyaromatic hydrocarbons (n=10), and personal care products (n=5) spanning a broad range of hydrophobicities (log Kow 1.5-7.6). Two modified POCIS-style samplers were investigated using macroporous nylon mesh membranes (35μm pores) and two different sorbent materials (i.e. Oasis HLB and Dowex Optipore L-493). A recently developed design, the Sentinel Sampler (ABS Materials), utilizing Osorb media enclosed within stainless steel mesh (145μm pores), was also investigated. Relatively high sampling rates (Rs) were achieved for all sampler configurations during the short eight-day exposure (4300-27mL/d). Under flow conditions, median Rs were approximately 5-10 times higher for POCIS-style samplers and 27 times higher for Sentinel Samplers, as compared to static conditions. The ability of samplers to rapidly measure hydrophobic contaminants may be a trade off with increased flow dependence. Analyte accumulation was integrative under pulsed and continuous exposures for POCIS-style samplers with mean difference between treatments of 11% and 33%; however, accumulation into Sentinel Samplers was more variable. Collectively, results show that reducing membrane limitations allows for rapid, integrative accumulation of a broad range of analytes even under pulsed exposures. As such, these sampler designs may be suitable for monitoring environmental substances that have short aquatic half-lives. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. THE POTENTIAL INFLUENCES OF FACE VELOCITY ON PM ARTIFACT LOSSES FOR EXPOSURE SAMPLERS USING TEFLON FILTER COLLECTION SUBSTRATES

    Science.gov (United States)

    The influences of artifact formations and losses on Particulate Matter (PM) sampler collection surfaces are well documented, especially for nitrates (Hering and Cass, 1999), and SVOC's (McDow, 1999), and more recently for speciated carbon (Turpin and Lim, 2001). These artifact...

  10. A finite-volume HLLC-based scheme for compressible interfacial flows with surface tension

    Energy Technology Data Exchange (ETDEWEB)

    Garrick, Daniel P. [Department of Aerospace Engineering, Iowa State University, Ames, IA (United States); Owkes, Mark [Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, MT (United States); Regele, Jonathan D., E-mail: jregele@iastate.edu [Department of Aerospace Engineering, Iowa State University, Ames, IA (United States)

    2017-06-15

    Shock waves are often used in experiments to create a shear flow across liquid droplets to study secondary atomization. Similar behavior occurs inside of supersonic combustors (scramjets) under startup conditions, but it is challenging to study these conditions experimentally. In order to investigate this phenomenon further, a numerical approach is developed to simulate compressible multiphase flows under the effects of surface tension forces. The flow field is solved via the compressible multicomponent Euler equations (i.e., the five equation model) discretized with the finite volume method on a uniform Cartesian grid. The solver utilizes a total variation diminishing (TVD) third-order Runge–Kutta method for time-marching and second order TVD spatial reconstruction. Surface tension is incorporated using the Continuum Surface Force (CSF) model. Fluxes are upwinded with a modified Harten–Lax–van Leer Contact (HLLC) approximate Riemann solver. An interface compression scheme is employed to counter numerical diffusion of the interface. The present work includes modifications to both the HLLC solver and the interface compression scheme to account for capillary force terms and the associated pressure jump across the gas–liquid interface. A simple method for numerically computing the interface curvature is developed and an acoustic scaling of the surface tension coefficient is proposed for the non-dimensionalization of the model. The model captures the surface tension induced pressure jump exactly if the exact curvature is known and is further verified with an oscillating elliptical droplet and Mach 1.47 and 3 shock-droplet interaction problems. The general characteristics of secondary atomization at a range of Weber numbers are also captured in a series of simulations.

  11. A finite-volume HLLC-based scheme for compressible interfacial flows with surface tension

    Science.gov (United States)

    Garrick, Daniel P.; Owkes, Mark; Regele, Jonathan D.

    2017-06-01

    Shock waves are often used in experiments to create a shear flow across liquid droplets to study secondary atomization. Similar behavior occurs inside of supersonic combustors (scramjets) under startup conditions, but it is challenging to study these conditions experimentally. In order to investigate this phenomenon further, a numerical approach is developed to simulate compressible multiphase flows under the effects of surface tension forces. The flow field is solved via the compressible multicomponent Euler equations (i.e., the five equation model) discretized with the finite volume method on a uniform Cartesian grid. The solver utilizes a total variation diminishing (TVD) third-order Runge-Kutta method for time-marching and second order TVD spatial reconstruction. Surface tension is incorporated using the Continuum Surface Force (CSF) model. Fluxes are upwinded with a modified Harten-Lax-van Leer Contact (HLLC) approximate Riemann solver. An interface compression scheme is employed to counter numerical diffusion of the interface. The present work includes modifications to both the HLLC solver and the interface compression scheme to account for capillary force terms and the associated pressure jump across the gas-liquid interface. A simple method for numerically computing the interface curvature is developed and an acoustic scaling of the surface tension coefficient is proposed for the non-dimensionalization of the model. The model captures the surface tension induced pressure jump exactly if the exact curvature is known and is further verified with an oscillating elliptical droplet and Mach 1.47 and 3 shock-droplet interaction problems. The general characteristics of secondary atomization at a range of Weber numbers are also captured in a series of simulations.

  12. Finite Element Surface Registration Incorporating Curvature, Volume Preservation, and Statistical Model Information

    Directory of Open Access Journals (Sweden)

    Thomas Albrecht

    2013-01-01

    Full Text Available We present a novel method for nonrigid registration of 3D surfaces and images. The method can be used to register surfaces by means of their distance images, or to register medical images directly. It is formulated as a minimization problem of a sum of several terms representing the desired properties of a registration result: smoothness, volume preservation, matching of the surface, its curvature, and possible other feature images, as well as consistency with previous registration results of similar objects, represented by a statistical deformation model. While most of these concepts are already known, we present a coherent continuous formulation of these constraints, including the statistical deformation model. This continuous formulation renders the registration method independent of its discretization. The finite element discretization we present is, while independent of the registration functional, the second main contribution of this paper. The local discontinuous Galerkin method has not previously been used in image registration, and it provides an efficient and general framework to discretize each of the terms of our functional. Computational efficiency and modest memory consumption are achieved thanks to parallelization and locally adaptive mesh refinement. This allows for the first time the use of otherwise prohibitively large 3D statistical deformation models.

  13. Curling probe measurement of large-volume pulsed plasma confined by surface magnetic field

    Science.gov (United States)

    Pandey, Anil; Sakakibara, Wataru; Matsuoka, Hiroyuki; Nakamura, Keiji; Sugai, Hideo; Chubu University Team; DOWA Thermotech Collaboration

    2015-09-01

    Curling probe (CP) has recently been developed which enables the local electron density measurement even in plasma for non-conducting film CVD. The electron density is obtained from a shift of resonance frequency of spiral antenna in discharge ON and OFF monitored by a network analyzer (NWA). In case of a pulsed glow discharge, synchronization of discharge pulse with frequency sweep of NWA must be established. In this paper, we report time and space-resolved CP measurement of electron density in a large volume plasma (80 cm diameter, 110 cm length) confined by surface magnetic field (multipole cusp field ~0.03 T). For plasma-aided modification of metal surface, the plasma is produced by 1 kV glow discharge at pulse frequency of 0.3 - 25 kHz with various duty ratio in gas (Ar, N2, C2H2) at pressure ~ 1 Pa. A radially movable CP revealed a remarkable effect of surface magnetic confinement: detach of plasma from the vessel wall and a fairly uniform plasma in the central region. In afterglow phase, the electron density was observed to decrease much faster in C2H2 discharge than in Ar discharge.

  14. Extended volume and surface scatterometer for optical characterization of 3D-printed elements

    Science.gov (United States)

    Dannenberg, Florian; Uebeler, Denise; Weiß, Jürgen; Pescoller, Lukas; Weyer, Cornelia; Hahlweg, Cornelius

    2015-09-01

    The use of 3d printing technology seems to be a promising way for low cost prototyping, not only of mechanical, but also of optical components or systems. It is especially useful in applications where customized equipment repeatedly is subject to immediate destruction, as in experimental detonics and the like. Due to the nature of the 3D-printing process, there is a certain inner texture and therefore inhomogeneous optical behaviour to be taken into account, which also indicates mechanical anisotropy. Recent investigations are dedicated to quantification of optical properties of such printed bodies and derivation of corresponding optimization strategies for the printing process. Beside mounting, alignment and illumination means, also refractive and reflective elements are subject to investigation. The proposed measurement methods are based on an imaging nearfield scatterometer for combined volume and surface scatter measurements as proposed in previous papers. In continuation of last year's paper on the use of near field imaging, which basically is a reflective shadowgraph method, for characterization of glossy surfaces like printed matter or laminated material, further developments are discussed. The device has been extended for observation of photoelasticity effects and therefore homogeneity of polarization behaviour. A refined experimental set-up is introduced. Variation of plane of focus and incident angle are used for separation of various the images of the layers of the surface under test, cross and parallel polarization techniques are applied. Practical examples from current research studies are included.

  15. Crack surface extraction of industrial CT volume data using FPIT and planelet.

    Science.gov (United States)

    Li, Zongjian; Zeng, Li; Zou, Xiaobing; Xiang, Caibing

    2011-01-01

    As an advanced nondestructive testing (NDT) technology, industrial computed tomography (ICT) has been widely applied to diversified areas. In modern industry, ICT is especially useful for analyzing inner defects of complex and close work pieces. The common defects of work pieces include gas cavities, slag inclusions, cracks and shrinking cavities. Only cracks are often caused by fatigue usage. Precisely extracting a crack is important to estimate the remaining secure service time of the work piece. This paper presents a crack surface extraction method of ICT volume data based on finite plane integral transform (FPIT) and planelet. FPIT and planelet, as new methods of multiscale geometric analysis (MGA), have distinct discrimination for different plane singularities. Within the paper, firstly the definitions of FPIT and planelet are introduced. Secondly, after analyzing the components and relationship of planelet at monoscale, a fast performance of planelet transform is designed. Thirdly, the steps of the proposed crack surface extraction method are described. In numeric experiment, compared with the method of 3D facet model, C-V model and 3D wavelet respectively, the proposed method can extract the crack surface full and continuously, which,is robust to noise.

  16. Methodology for profiling anti-androgen mixtures in river water using multiple passive samplers and bioassay-directed analyses.

    Science.gov (United States)

    Liscio, Camilla; Abdul-Sada, Alaa; Al-Salhi, Raghad; Ramsey, Michael H; Hill, Elizabeth M

    2014-06-15

    The identification of endocrine disrupting chemicals in surface waters is challenging as they comprise a variety of structures which are often present at nanomolar concentrations and are temporally highly variable. Hence, a holistic passive sampling approach can be an efficient technique to overcome these limitations. In this study, a combination of 4 different passive samplers used for sampling polar (POCIS Apharm and POCIS Bpesticide) and apolar compounds (LDPE low density polyethylene membranes, and silicone strips) were used to profile anti-androgenic activity present in river water contaminated by a wastewater effluent. Extracts of passive samplers were analysed using HPLC fractionation in combination with an in vitro androgen receptor antagonist screen (YAS). Anti-androgenic activity was detected in extracts from silicone strips and POCIS A/B at (mean ± SD) 1.1 ± 0.1 and 0.55 ± 0.06 mg flutamide standard equivalents/sampler respectively, but was not detected in LDPE sampler extracts. POCIS samplers revealed higher selectivity for more polar anti-androgenic HPLC fractions compared with silicone strips. Over 31 contaminants were identified which showed inhibition of YAS activity and were potential anti-androgens, and these included fungicides, germicides, flame retardants and pharmaceuticals. This study reveals that passive sampling, using a combination of POCIS A and silicone samplers, is a promising tool for screening complex mixture of anti-androgenic contaminants present in surface waters, with the potential to identify new and emerging structures with endocrine disrupting activity.

  17. Phase contrast imaging reveals low lung volumes and surface areas in the developing marsupial.

    Directory of Open Access Journals (Sweden)

    Shannon J Simpson

    Full Text Available Marsupials are born with immature lungs when compared to eutherian mammals and rely, to various extents, on cutaneous gas exchange in order to meet metabolic requirements. Indeed, the fat-tailed dunnart is born with lungs in the canalicular stage of development and relies almost entirely on the skin for gas exchange at birth; consequently undergoing the majority of lung development in air. Plane radiographs and computed tomography data sets were acquired using phase contrast imaging with a synchrotron radiation source for two marsupial species, the fat-tailed dunnart and the larger tammar wallaby, during the first weeks of postnatal life. Phase contrast imaging revealed that only two lung sacs contain air after the first hour of life in the fat-tailed dunnart. While the lung of the tammar wallaby was comparatively more developed, both species demonstrated massive increases in air sac number and architectural complexity during the postnatal period. In addition, both the tammar wallaby and fat-tailed dunnart had lower lung volumes and parenchymal surface areas than were expected from morphometrically determined allometric equations relating these variables to body mass during the neonatal period. However, lung volume is predicted to scale with mass as expected after the neonatal marsupial reaches a body mass of ∼1 g and no longer relies on the skin for gas exchange. Decreased lung volume in the marsupial neonate further supports the maxim that cutaneous gas exchange occurs in the marsupial neonate because the respiratory apparatus is not yet capable of meeting the gas exchange requirements of the newborn.

  18. Manufacturing lot affects polyethylene tibial insert volume, thickness, and surface geometry.

    Science.gov (United States)

    Teeter, Matthew G; Milner, Jaques S; MacDonald, Steven J; Naudie, Douglas D R

    2013-08-01

    To perform wear measurements on retrieved joint replacement implants, a reference geometry of the implant's original state is required. Since implants are rarely individually scanned before implantation, a different, new implant of the same kind and size is frequently used. However, due to manufacturing variability, errors may be introduced into these measurements, as the dimensions between the retrieved and reference components may not be exactly the same. The hypothesis of this study was that new polyethylene tibial inserts from different manufacturing lots would demonstrate greater variability than those from the same lot. In total, 12 new tibial inserts of the same model and size were obtained, 5 from the same lot and the remainder from different lots. The geometry of each tibial insert was obtained using microcomputed tomography. Measurements of tibial insert volume, thickness, and three-dimensional surface deviations were obtained and compared between tibial inserts from the same and different manufacturing lots. Greater variability was found for the tibial inserts from different manufacturing lots for all types of measurements, including a fourfold difference in volume variability (p manufacturing lots for use as the reference geometry.

  19. Highspeed manufacturing of periodical surface and in-volume nanostructures by fs-laser direct writing

    Science.gov (United States)

    Gottmann, J.; Wortmann, D.; Brandt, N.

    2008-02-01

    Sub wavelength ripples (spacing glass fiber laser (τ=400fs, λ=1045nm, f=0.1-5MHz) over the surface of various materials like amorphous Nd:Gd 3Ga 5O 12 films 1 μm in thickness on YAG substrates, diamond, polytetrafluoroethylene, LiF, MgF II, ZBLAN, Al IIO 3, LiNbO 3, SiO II, Si, Cu and Au. The ripple patterns extend coherently over many overlapping laser pulses and scanning tracks. Investigated are the dependence of the ripple spacing Λ on the material, the lateral distance of the laser pulses, the N.A. of the focussing optics, the repetition rate and the applied wavelength. The ripples are characterised using electron microscopy. Some possible models for the origin of the ripple growth are discussed. New results concerning the scaling of the production process using a high repetition rate laser and a fast translation stage are demonstrated. The cross-sections of the ripples are investigated using electron microscopy. A very large aspect ration of ~10 is observed for the periodical nanostructures in fused silica. Using in-volume selective laser etching (ISLE) of sapphire results in deep hollow nanoplanes ~200 nm in width and up to 1 mm in length. Microchannels have been produced using in-volume selective laser etching with a scanning speed of 1 mm/s.

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

    Science.gov (United States)

    Gero, A; Tomb, T

    1988-06-01

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

  1. Radial variations of the volume and surface star formation laws in the Galaxy

    Science.gov (United States)

    Sofue, Yoshiaki

    2017-08-01

    Variation of the volume and surface Schmidt laws (star formation or SF law) with the galacto-centric distance R was investigated using 3D distributions of H II regions, H i, and molecular (H2) gases in the Milky Way. Both the power-law index and SF coefficient were found to vary with R. The index is flatter in the inner disc than in the outer Galaxy, and the coefficient is larger in the inner disc, decreasing steeply outwardly. There is also a mutual anti-correlation between the index and SF coefficient, and the SF law can be expressed by a single-parameter function of the SF coefficient. The variable SF law is discussed in relation to self-regulation of SF.

  2. MHD flow of dusty nanofluid over a stretching surface with volume fraction of dust particles

    Directory of Open Access Journals (Sweden)

    Sandeep Naramgari

    2016-06-01

    Full Text Available In this study we analyzed the momentum and heat transfer behavior of MHD nanofluid embedded with conducting dust particles past a stretching surface in the presence of volume fraction of dust particles. The governing equations of the flow and heat transfer are transformed into nonlinear ordinary differential equations by using similarity transformation and then solved numerically using Runge–Kutta based shooting technique. The effect of non-dimensional governing parameters on velocity and temperature profiles of the flow are discussed and presented through graphs. Additionally friction factor and the Nusselt number have also been computed. Under some special conditions, numerical results obtained by the present study were compared with the existed studies. The result of the present study proves to be highly satisfactory. The results indicate that an increase in the interaction between the fluid and particle phase enhances the heat transfer rate and reduces the friction factor.

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

    Directory of Open Access Journals (Sweden)

    P.Nassiri

    1988-08-01

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

  4. Beam formation in CERNs cesiated surfaces and volume H- ion sources

    Science.gov (United States)

    Mochalskyy, Serhiy; Lettry, Jacques; Minea, Tiberiu

    2016-08-01

    At CERN, a high performance negative ion (NI) source is required for the 160 MeV H- linear accelerator named Linac4. The source should deliver 80 mA H- ion beams within an emittance of 0.25 mm·mrad. For this purpose two ion sources were developed: IS01 is based on the NI volume production and IS02 provides additional NI by surface production via H interaction on a cesiated Molybdenum plasma electrode. The development of negative ion sources for Linac4 is accompanied by modelling activities. ONIX code has been modified and adapted to investigate the transport of NI and electrons in the extraction region of the CERN negative ion sources. The simulated results from modeling of IS01 and IS02 extraction regions, which were obtained in 2012 during source commissioning, are presented and benchmarked with experimental measurements obtained after 2013. The formation of the plasma meniscus and the screening of the extraction field by the source plasma are discussed. The NI production is compared between two types of sources, the first one based on volume production only and the second one encompassing NI cesiated surface production. For the IS02 source, different states of conditioning were simulated by changing the NI emission flux from the plasma electrode and Cs+ density in the bulk plasma region. The numerical results show that in low work function regime, with high NI surface emission rate of 3000 A m-2 and Cs-density of nCs+ = 3.8 × 1016 m-3, the total extracted NI current could reach ~80 mA. At the less favorable Cs-coverage, when the surface NI emission rate becomes significantly lower, namely 300 A m-2 with nCs+ = 3.3 × 1015 m-3, the total extracted NI current only reaches ~20 mA. A good agreement between simulation and experimental results is observed in terms of extracted NI current for both extraction systems, including the case of reversed extraction potential that corresponds to positive (H+) ion extraction.

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

    Science.gov (United States)

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

    2016-03-01

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

  6. 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...

  7. 7 CFR 800.185 - Duties of official personnel and warehouse samplers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Duties of official personnel and warehouse samplers... official personnel and warehouse samplers. (a) General. Official personnel and warehouse samplers shall... of § 800.161. (d) Scope of operations. Official personnel and warehouse samplers shall operate...

  8. Field evaluation of the error arising from inadequate time averaging in the standard use of depth-integrating suspended-sediment samplers

    Science.gov (United States)

    Topping, David J.; Rubin, David M.; Wright, Scott A.; Melis, Theodore S.

    2011-01-01

    Several common methods for measuring suspended-sediment concentration in rivers in the United States use depth-integrating samplers to collect a velocity-weighted suspended-sediment sample in a subsample of a river cross section. Because depth-integrating samplers are always moving through the water column as they collect a sample, and can collect only a limited volume of water and suspended sediment, they collect only minimally time-averaged data. Four sources of error exist in the field use of these samplers: (1) bed contamination, (2) pressure-driven inrush, (3) inadequate sampling of the cross-stream spatial structure in suspended-sediment concentration, and (4) inadequate time averaging. The first two of these errors arise from misuse of suspended-sediment samplers, and the third has been the subject of previous study using data collected in the sand-bedded Middle Loup River in Nebraska. Of these four sources of error, the least understood source of error arises from the fact that depth-integrating samplers collect only minimally time-averaged data. To evaluate this fourth source of error, we collected suspended-sediment data between 1995 and 2007 at four sites on the Colorado River in Utah and Arizona, using a P-61 suspended-sediment sampler deployed in both point- and one-way depth-integrating modes, and D-96-A1 and D-77 bag-type depth-integrating suspended-sediment samplers. These data indicate that the minimal duration of time averaging during standard field operation of depth-integrating samplers leads to an error that is comparable in magnitude to that arising from inadequate sampling of the cross-stream spatial structure in suspended-sediment concentration. This random error arising from inadequate time averaging is positively correlated with grain size and does not largely depend on flow conditions or, for a given size class of suspended sediment, on elevation above the bed. Averaging over time scales >1 minute is the likely minimum duration required

  9. The Genetic Association Between Neocortical Volume and General Cognitive Ability Is Driven by Global Surface Area Rather Than Thickness

    Science.gov (United States)

    Vuoksimaa, Eero; Panizzon, Matthew S.; Chen, Chi-Hua; Fiecas, Mark; Eyler, Lisa T.; Fennema-Notestine, Christine; Hagler, Donald J.; Fischl, Bruce; Franz, Carol E.; Jak, Amy; Lyons, Michael J.; Neale, Michael C.; Rinker, Daniel A.; Thompson, Wesley K.; Tsuang, Ming T.; Dale, Anders M.; Kremen, William S.

    2015-01-01

    Total gray matter volume is associated with general cognitive ability (GCA), an association mediated by genetic factors. It is expectable that total neocortical volume should be similarly associated with GCA. Neocortical volume is the product of thickness and surface area, but global thickness and surface area are unrelated phenotypically and genetically in humans. The nature of the genetic association between GCA and either of these 2 cortical dimensions has not been examined. Humans possess greater cognitive capacity than other species, and surface area increases appear to be the primary driver of the increased size of the human cortex. Thus, we expected neocortical surface area to be more strongly associated with cognition than thickness. Using multivariate genetic analysis in 515 middle-aged twins, we demonstrated that both the phenotypic and genetic associations between neocortical volume and GCA are driven primarily by surface area rather than thickness. Results were generally similar for each of 4 specific cognitive abilities that comprised the GCA measure. Our results suggest that emphasis on neocortical surface area, rather than thickness, could be more fruitful for elucidating neocortical–GCA associations and identifying specific genes underlying those associations. PMID:24554725

  10. The Genetic Association Between Neocortical Volume and General Cognitive Ability Is Driven by Global Surface Area Rather Than Thickness.

    Science.gov (United States)

    Vuoksimaa, Eero; Panizzon, Matthew S; Chen, Chi-Hua; Fiecas, Mark; Eyler, Lisa T; Fennema-Notestine, Christine; Hagler, Donald J; Fischl, Bruce; Franz, Carol E; Jak, Amy; Lyons, Michael J; Neale, Michael C; Rinker, Daniel A; Thompson, Wesley K; Tsuang, Ming T; Dale, Anders M; Kremen, William S

    2015-08-01

    Total gray matter volume is associated with general cognitive ability (GCA), an association mediated by genetic factors. It is expectable that total neocortical volume should be similarly associated with GCA. Neocortical volume is the product of thickness and surface area, but global thickness and surface area are unrelated phenotypically and genetically in humans. The nature of the genetic association between GCA and either of these 2 cortical dimensions has not been examined. Humans possess greater cognitive capacity than other species, and surface area increases appear to be the primary driver of the increased size of the human cortex. Thus, we expected neocortical surface area to be more strongly associated with cognition than thickness. Using multivariate genetic analysis in 515 middle-aged twins, we demonstrated that both the phenotypic and genetic associations between neocortical volume and GCA are driven primarily by surface area rather than thickness. Results were generally similar for each of 4 specific cognitive abilities that comprised the GCA measure. Our results suggest that emphasis on neocortical surface area, rather than thickness, could be more fruitful for elucidating neocortical-GCA associations and identifying specific genes underlying those associations.

  11. A New Efficient Finite Volume Modeling of Small Amplitude Free Surface Flows with Unstructured Grid

    Institute of Scientific and Technical Information of China (English)

    L(U) Biao

    2013-01-01

    A staggered finite-volume technique for non-hydrostatic,small amplitude free surface flow governed by the incompressible Navier-Stokes equations is presented there is a proper balance between accuracy and computing time.The advection and horizontal diffusion terms in the momentum equation are discretized by an integral interpolation method on the orthogonal unstructured staggered mesh and,while it has the attractive property of being conservative.The pressure-correction algorithm is employed for the non-hydrostatic pressure in order to achieve second-order temporal accuracy.A conservative scalar transport algorithm is also applied to discretize k-ε equations in this model.The eddy viscosity is calculated from the k-ε turbulent model.The resulting model is mass and momentum conservative.The model is verified by two examples to simulate unsteady small amplitude free surface flows where non-hydrostatic pressures have a considerable effect on the velocity field,and then applied to simulate the tidal flow in the Bohai Sea.

  12. 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.

  13. Cortical thickness, surface area and volume measures in Parkinson's disease, multiple system atrophy and progressive supranuclear palsy.

    Directory of Open Access Journals (Sweden)

    Amanda Worker

    Full Text Available Parkinson's disease (PD, Multiple System Atrophy (MSA and Progressive Supranuclear Palsy (PSP are neurodegenerative diseases that can be difficult to distinguish clinically. The objective of the current study was to use surface-based analysis techniques to assess cortical thickness, surface area and grey matter volume to identify unique morphological patterns of cortical atrophy in PD, MSA and PSP and to relate these patterns of change to disease duration and clinical features.High resolution 3D T1-weighted MRI volumes were acquired from 14 PD patients, 18 MSA, 14 PSP and 19 healthy control participants. Cortical thickness, surface area and volume analyses were carried out using the automated surface-based analysis package FreeSurfer (version 5.1.0. Measures of disease severity and duration were assessed for correlation with cortical morphometric changes in each clinical group.Results show that in PSP, widespread cortical thinning and volume loss occurs within the frontal lobe, particularly the superior frontal gyrus. In addition, PSP patients also displayed increased surface area in the pericalcarine. In comparison, PD and MSA did not display significant changes in cortical morphology.These results demonstrate that patients with clinically established PSP exhibit distinct patterns of cortical atrophy, particularly affecting the frontal lobe. These results could be used in the future to develop a useful clinical application of MRI to distinguish PSP patients from PD and MSA patients.

  14. Static allometry of unicellular green algae: scaling of cellular surface area and volume in the genus Micrasterias (Desmidiales).

    Science.gov (United States)

    Neustupa, J

    2016-02-01

    The surface area-to-volume ratio of cells is one of the key factors affecting fundamental biological processes and, thus, fitness of unicellular organisms. One of the general models for allometric increase in surface-to-volume scaling involves fractal-like elaboration of cellular surfaces. However, specific data illustrating this pattern in natural populations of the unicellular organisms have not previously been available. This study shows that unicellular green algae of the genus Micrasterias (Desmidiales) have positive allometric surface-to-volume scaling caused by changes in morphology of individual species, especially in the degree of cell lobulation. This allometric pattern was also detected within most of the cultured and natural populations analysed. Values of the allometric S:V scaling within individual populations were closely correlated to the phylogenetic structure of the clade. In addition, they were related to species-specific cellular morphology. Individual populations differed in their allometric patterns, and their position in the allometric space was strongly correlated with the degree of allometric S:V scaling. This result illustrates that allometric shape patterns are an important correlate of the capacity of individual populations to compensate for increases in their cell volumes by increasing the surface area. However, variation in allometric patterns was not associated with phylogenetic structure. This indicates that the position of the populations in the allometric space was not evolutionarily conserved and might be influenced by environmental factors.

  15. Fluidized Bed Asbestos Sampler Design and Testing

    Energy Technology Data Exchange (ETDEWEB)

    Karen E. Wright; Barry H. O' Brien

    2007-12-01

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

  16. Quantitative Magnetic Resonance Imaging of Brainstem Volumes, Plaques, and Surface Area in the Occipital Regions of Patients with Multiple Sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Alper, F.; Kantarci, M.; Altunkaynak, E.; Varoglu, A. O.; Karaman, A.; Oral, E.; Okur, A. [Ataturk Univ., Erzurum (Turkey). Depts. of Radiology, Histology, Neurology and Embryology, Psychiatry

    2006-07-15

    Purpose: To determine brainstem volumes, number of plaques, and surface areas in the occipital lobes of patients with relapsing remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS), and to investigate whether there is any correlation between brainstem volume and the number/surface areas of plaque in the occipital lobes. Material and Methods: Magnetic resonance imaging was obtained on 14 relapsing-remitting (RR) and 13 secondary progressive (SP) MS patients and 26 female control subjects. The Cavalieri method was used by modern design stereology to measure brainstem volume. The point-counting grid was used to evaluate sclerotic plaque surface areas in the occipital lobe. The number of plaques in the imaging section was calculated. Results: Brainstem volumes for RR and SP with multiple sclerosis and control subjects were 3647 mm{sup 3} , 3515 mm{sup 3} , and 4517 mm{sup 3} , respectively. Mean number of plaques in the right-left occipital lobe was found to be 2.7-3.4 in RR-MS and 5.2-2.8 in SP-MS. Mean plaque surface area in the right-left occipital lobe was determined to be 58.52-88.24 mm{sup 2} in RR MS and 124.3-64.82 mm{sup 2} in SP MS. Brainstem volumes were significantly reduced in both groups of patients with MS compared to controls ( P <0.01). Conclusion: Magnetic-resonance-estimated volume and surface area values in multiple sclerosis may facilitate our understanding of the clinical situation of patients and provide a simple index for evaluating therapeutic efficiency.

  17. Characterization of the intragranular water regime within subsurface sediments: Pore volume, surface area, and mass transfer limitations

    Science.gov (United States)

    Hay, Michael B.; Stoliker, Deborah L.; Davis, James A.; Zachara, John M.

    2011-10-01

    Although "intragranular" pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high-resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ˜1% of the solid volume and intragranular surface areas of ˜20%-35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity.

  18. Characterization of the intragranular water regime within subsurface sediments: pore volume, surface area, and mass transfer limitations

    Science.gov (United States)

    Hay, Michael B.; Stoliker, Deborah L.; Davis, James A.; Zachara, John M.

    2011-01-01

    Although "intragranular" pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high-resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ~1% of the solid volume and intragranular surface areas of ~20%–35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity.

  19. SURFACE AREA, VOLUME, MASS, AND DENSITY DISTRIBUTIONS FOR SIZED BOMASS PARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    Ramanathan Sampath

    2004-05-01

    This semi-annual technical progress report describes work performed at Morehouse College under DOE Grant No. DE-FC26-04NT42130 during the period July 01, 2004 to December 31, 2004 which covers the first six months of the project. Presently work is in progress to characterize surface area, volume, mass, and density distributions for sized biomass particles. During this reporting period, supply requests were processed and supplies including biomass test particles (hardwood sawdust AI14546) in the size range of 100-200 microns were obtained from a cofiring pilot plant research facility owned by Southern Company, Birmingham, AL. Morehouse has completed setting up of the gravimetric technique measurement system in the heat transfer laboratory, department of physics and dual degree engineering, Morehouse College. Simultaneously, REM, our subcontractor, has completed setting up of the electrodynamic balance (EDB) measurement system to characterize shape and mass for individual biomass particles. Testing of the gravimetric system, and calibration of the cameras and imaging systems using known sizes of polystyrene particles are in progress.

  20. Curling probe measurement of a large-volume pulsed plasma with surface magnetic confinement

    Science.gov (United States)

    Pandey, A.; Tashiro, H.; Sakakibara, W.; Nakamura, K.; Sugai, H.

    2016-12-01

    A curling probe (CP) based on microwave resonance is applied to the measurement of electron density in a pulsed DC glow discharge under surface magnetic confinement (SMC) provided by a number of permanent magnets on a chamber wall. Owing to the SMC effects, a 1 m scale large-volume plasma is generated by a relatively low voltage (~1 kV) at low pressure (~1 Pa) in various gases (Ar, CH4, and C2H2). Temporal variation of the electron density is measured for pulse frequency f  =  0.5-25 kHz for various discharge-on times (T ON) with a high resolution time (~0.2 µs), using the on-point mode. In general, the electron density starts to increase at time t  =  0 after turn-on of the discharge voltage, reaches peak density at t  =  T ON, and then decreases after turn-off. The peak electron density is observed to increase with the pulse frequency f for constant T ON owing to the residual plasma. This dependence is successfully formulated using a semi-empirical model. The spatio-temporal evolution of the cathode sheath in the pulsed discharge is revealed by a 1 m long movable CP. The measured thickness of the high-voltage cathode fall in a steady state coincides with the value of the so-called Child-Langmuir sheath.

  1. Reliable nanomaterial classification of powders using the volume-specific surface area method

    Science.gov (United States)

    Wohlleben, Wendel; Mielke, Johannes; Bianchin, Alvise; Ghanem, Antoine; Freiberger, Harald; Rauscher, Hubert; Gemeinert, Marion; Hodoroaba, Vasile-Dan

    2017-02-01

    The volume-specific surface area (VSSA) of a particulate material is one of two apparently very different metrics recommended by the European Commission for a definition of "nanomaterial" for regulatory purposes: specifically, the VSSA metric may classify nanomaterials and non-nanomaterials differently than the median size in number metrics, depending on the chemical composition, size, polydispersity, shape, porosity, and aggregation of the particles in the powder. Here we evaluate the extent of agreement between classification by electron microscopy (EM) and classification by VSSA on a large set of diverse particulate substances that represent all the anticipated challenges except mixtures of different substances. EM and VSSA are determined in multiple labs to assess also the level of reproducibility. Based on the results obtained on highly characterized benchmark materials from the NanoDefine EU FP7 project, we derive a tiered screening strategy for the purpose of implementing the definition of nanomaterials. We finally apply the screening strategy to further industrial materials, which were classified correctly and left only borderline cases for EM. On platelet-shaped nanomaterials, VSSA is essential to prevent false-negative classification by EM. On porous materials, approaches involving extended adsorption isotherms prevent false positive classification by VSSA. We find no false negatives by VSSA, neither in Tier 1 nor in Tier 2, despite real-world industrial polydispersity and diverse composition, shape, and coatings. The VSSA screening strategy is recommended for inclusion in a technical guidance for the implementation of the definition.

  2. Surface area and volume fraction of random open-pore systems

    Science.gov (United States)

    Hermann, H.; Elsner, A.; Stoyan, D.

    2013-12-01

    For the first time, explicit approximate formulas are presented for the volume fraction and specific surface area of random open-pore systems with poly-disperse pore size distributions. It is shown that the formulas are valid for broad classes of models for porous media characterized by tunable pore size distributions and a variable degree of inter-penetrability of pores. The formulas for the poly-disperse case are based on expressions derived previously for mono-disperse penetrable-sphere models. The results are obtained by analysis of a series of open-pore models, which are prepared by computer simulation of systems of randomly packed partially penetrable spheres with various poly-disperse size distributions such as gamma, lognormal, and Gaussian. The formulas are applied in a study of atomic layer deposition processes on open-pore systems, and the effective Young's modulus and the effective thermal conductivity of Al2O3 coated porous polypropylene electrodes for lithium ion batteries are predicted.

  3. Characterization of polyurethane foam (PUF) and sorbent impregnated PUF (SIP) disk passive air samplers for measuring organophosphate flame retardants.

    Science.gov (United States)

    Abdollahi, Atousa; Eng, Anita; Jantunen, Liisa M; Ahrens, Lutz; Shoeib, Mahiba; Parnis, J Mark; Harner, Tom

    2017-01-01

    This study aimed to characterize the uptake of organophosphate esters (OPEs) by polyurethane foam (PUF) and sorbent-impregnated polyurethane foam (SIP) disk passive air samplers (PAS). Atmospheric OPE concentrations were monitored with high-volume active air samplers (HV-AAS) that were co-deployed with passive air samplers. Samples were analyzed for tris(2-chloroisopropyl) phosphate (TCIPP), tri(phenyl) phosphate (TPhP), tris(2-chloroethyl) phosphate (TCEP), and tris(2,3-dichloropropyl) phosphate (TDCIPP). The mean concentration of ∑OPEs in air was 2650 pg/m(3) for the HV-AAS. Sampling rates and the passive sampler medium (PSM)-air partition coefficient (KPSM-Air) were calculated for individual OPEs. The average calculated sampling rates (R) for the four OPEs were 3.6 ± 1.2 and 4.2 ± 2.0 m(3)/day for the PUF and SIP disks, respectively, and within the range of the recommended default value of 4 ± 2 m(3)/day. Since most of the OPEs remained in the linear uptake phase during the study, COSMO-RS solvation theory and an oligomer-based model were used to estimate KPUF-Air for the OPEs. The estimated values of log KPUF-Air were 7.45 (TCIPP), 9.35 (TPhP), 8.44 (TCEP), and 9.67 (TDCIPP). Finally, four configurations of the PUF and SIP disks were tested by adjusting the distance of the gap opening between the upper and lower domes of the sampler housing: i.e. 2 cm, 1 cm, no gap and 1 cm overlap. The sampling rate did not differ significantly between these four configurations (p < 0.05).

  4. Adsorption of charged and neutral polymer chains on silica surfaces: The role of electrostatics, volume exclusion, and hydrogen bonding

    Science.gov (United States)

    Spruijt, Evan; Biesheuvel, P. M.; de Vos, Wiebe M.

    2015-01-01

    We develop an off-lattice (continuum) model to describe the adsorption of neutral polymer chains and polyelectrolytes to surfaces. Our continuum description allows taking excluded volume interactions between polymer chains and ions directly into account. To implement those interactions, we use a modified hard-sphere equation of state, adapted for mixtures of connected beads. Our model is applicable to neutral, charged, and ionizable surfaces and polymer chains alike and accounts for polarizability effects of the adsorbed layer and chemical interactions between polymer chains and the surface. We compare our model predictions to data of a classical system for polymer adsorption: neutral poly(N -vinylpyrrolidone) (PVP) on silica surfaces. The model shows that PVP adsorption on silica is driven by surface hydrogen bonding with an effective maximum binding energy of about 1.3 kBT per PVP segment at low p H . As the p H increases, the Si-OH groups become increasingly dissociated, leading to a lower capacity for H bonding and simultaneous counterion accumulation and volume exclusion close to the surface. Together these effects result in a characteristic adsorption isotherm, with the adsorbed amount dropping sharply at a critical p H . Using this model for adsorption data on silica surfaces cleaned by either a piranha solution or an O2 plasma, we find that the former have a significantly higher density of silanol groups.

  5. Scaling of Haversian canal surface area to secondary osteon bone volume in ribs and limb bones.

    Science.gov (United States)

    Skedros, John G; Knight, Alex N; Clark, Gunnar C; Crowder, Christian M; Dominguez, Victoria M; Qiu, Shijing; Mulhern, Dawn M; Donahue, Seth W; Busse, Björn; Hulsey, Brannon I; Zedda, Marco; Sorenson, Scott M

    2013-06-01

    Studies of secondary osteons in ribs have provided a great deal of what is known about remodeling dynamics. Compared with limb bones, ribs are metabolically more active and sensitive to hormonal changes, and receive frequent low-strain loading. Optimization for calcium exchange in rib osteons might be achieved without incurring a significant reduction in safety factor by disproportionally increasing central canal size with increased osteon size (positive allometry). By contrast, greater mechanical loads on limb bones might favor reducing deleterious consequences of intracortical porosity by decreasing osteon canal size with increased osteon size (negative allometry). Evidence of this metabolic/mechanical dichotomy between ribs and limb bones was sought by examining relationships between Haversian canal surface area (BS, osteon Haversian canal perimeter, HC.Pm) and bone volume (BV, osteonal wall area, B.Ar) in a broad size range of mature (quiescent) osteons from adult human limb bones and ribs (modern and medieval) and various adult and subadult non-human limb bones and ribs. Reduced major axis (RMA) and least-squares (LS) regressions of HC.Pm/B.Ar data show that rib and limb osteons cannot be distinguished by dimensional allometry of these parameters. Although four of the five rib groups showed positive allometry in terms of the RMA slopes, nearly 50% of the adult limb bone groups also showed positive allometry when negative allometry was expected. Consequently, our results fail to provide clear evidence that BS/BV scaling reflects a rib versus limb bone dichotomy whereby calcium exchange might be preferentially enhanced in rib osteons.

  6. A minimally invasive micro sampler for quantitative sampling with an ultrahigh-aspect-ratio microneedle and a PDMS actuator.

    Science.gov (United States)

    Liu, Long; Wang, Yan; Yao, Jinyuan; Yang, Cuijun; Ding, Guifu

    2016-08-01

    This study describes a novel micro sampler consisting of an ultrahigh-aspect-ratio microneedle and a PDMS actuator. The microneedle was fabricated by a new method which introduced reshaped photoresist technology to form a flow channel inside. The microneedle includes two parts: shaft and pedestal. In this study, the shaft length is 1500 μm with a 45° taper angle on the tip and pedestal is 1000 μm. Besides, the shaft and pedestal are connected by an arc connection structure with a length of 600 μm. The microneedles have sufficient mechanical strength to insert into skin with a wide safety margin which was proved by mechanics tests. Moreover, a PDMS actuator with a chamber inside was designed and fabricated in this study. The chamber, acting as a reservoir in sampling process as well as providing power, was optimized by finite element analysis (FEA) to decrease dead volume and improve sampling precision. The micro sampler just needs finger press to activate the sampling process as well as used for quantitative micro injection to some extent. And a volume of 31.5 ± 0.8 μl blood was successfully sampled from the ear artery of a rabbit. This micro sampler is suitable for micro sampling for diagnose or therapy in biomedical field.

  7. Microplasticity of surfaces and small volumes: An investigation by atomic force microscopy

    Science.gov (United States)

    Kramer, Donald Eugene

    This study uses atomic force microscopy (AFM) to study the evolution of microplasticity at surfaces and small volumes. It is at these length scales that the assumptions of isotropic and homogenous material properties, two assumptions that underpin much of continuum mechanics, begin to break down. The study begins by examining the indentation of metallic single crystals. It has been suggested that nanoindentation provides a means by which energies associated with dislocation nucleation can be measured. AFM combined with indentation tests on tungsten and Fe 3%-Si single crystals at variable temperature and humidity demonstrates that asperities and oxide thickness play a significant role in the initial deformation process. A flaw based oxide fracture model is proposed that accounts for the asperity and oxide film thickness effects. Plastic zones around nano-contacts are then observed using AFM. This is done first for a range of bulk metals and is used to evaluate a simple model that allows determination of the yield strength from knowledge of the contact load and the extent of the plastic zone. The model is found to accurately predict the yield strength for a variety of metals. However, limits are placed on its applicability. The same technique is then applied to Al 2%-Si thin films on silicon and sapphire substrates. AFM is used to evaluate the evolution of the plastic zone around these contacts. It is demonstrated that the constraint between indenter and substrate controls the evolution of the plastic zone. Based on experimental plastic zone measurements, a first-order model for composite hardness is proposed that accounts for the increasing constraint on mean contact pressure. Finally, a bending fatigue system is developed with an eye toward investigating the fatigue response of thin films and the interaction between contact defects and cyclic loading. AFM is then used to measure slip upset in titanium subjected to large amplitude fully reversed bending fatigue

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

    Science.gov (United States)

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

    2013-02-01

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

  9. 2D and 3D milled surface roughness of high volume fraction SiCp/Al composites

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2015-06-01

    Full Text Available This paper presents a study on surface roughness generated by high speed milling of high volume fraction (65% silicon carbide particle-reinforced aluminum matrix (SiCp/Al composites. Typical 2D (Ra and Rz and 3D (Sa and Sq surface roughness parameters were selected to evaluate the influence of the milling parameters on the surface quality in comparison with aluminum alloy. The 3D topography of the milled surface was studied as well. The results indicate that 3D parameters (Sa and Sq are more capable to describe the influence of the milling parameters on the surface quality, and among them Sq is preferable due to its good sensitivity. Sq decreases with milling speed and increases with feed rate. The influence of axial depth of cut (ADOC is negligible.

  10. Conversion of a Surface Model of a Structure of Interest into a Volume Model for Medical Image Retrieval

    Directory of Open Access Journals (Sweden)

    Sarmad ISTEPHAN

    2015-06-01

    Full Text Available Volumetric medical image datasets contain vital information for noninvasive diagnosis, treatment planning and prognosis. However, direct and unlimited query of such datasets is hindered due to the unstructured nature of the imaging data. This study is a step towards the unlimited query of medical image datasets by focusing on specific Structures of Interest (SOI. A requirement in achieving this objective is having both the surface and volume models of the SOI. However, typically, only the surface model is available. Therefore, this study focuses on creating a fast method to convert a surface model to a volume model. Three methods (1D, 2D and 3D are proposed and evaluated using simulated and real data of Deep Perisylvian Area (DPSA within the human brain. The 1D method takes 80 msec for DPSA model; about 4 times faster than 2D method and 7.4 fold faster than 3D method, with over 97% accuracy. The proposed 1D method is feasible for surface to volume conversion in computer aided diagnosis, treatment planning and prognosis systems containing large amounts of unstructured medical images.

  11. Determination of the volume-specific surface area by using transmission electron tomography for characterization and definition of nanomaterials

    Directory of Open Access Journals (Sweden)

    Francisco Michel

    2011-05-01

    Full Text Available Abstract Background Transmission electron microscopy (TEM remains an important technique to investigate the size, shape and surface characteristics of particles at the nanometer scale. Resulting micrographs are two dimensional projections of objects and their interpretation can be difficult. Recently, electron tomography (ET is increasingly used to reveal the morphology of nanomaterials (NM in 3D. In this study, we examined the feasibility to visualize and measure silica and gold NM in suspension using conventional bright field electron tomography. Results The general morphology of gold and silica NM was visualized in 3D by conventional TEM in bright field mode. In orthoslices of the examined NM the surface features of a NM could be seen and measured without interference of higher or lower lying structures inherent to conventional TEM. Segmentation by isosurface rendering allowed visualizing the 3D information of an electron tomographic reconstruction in greater detail than digital slicing. From the 3D reconstructions, the surface area and the volume of the examined NM could be estimated directly and the volume-specific surface area (VSSA was calculated. The mean VSSA of all examined NM was significantly larger than the threshold of 60 m2/cm3. The high correlation between the measured values of area and volume gold nanoparticles with a known spherical morphology and the areas and volumes calculated from the equivalent circle diameter (ECD of projected nanoparticles (NP indicates that the values measured from electron tomographic reconstructions are valid for these gold particles. Conclusion The characterization and definition of the examined gold and silica NM can benefit from application of conventional bright field electron tomography: the NM can be visualized in 3D, while surface features and the VSSA can be measured.

  12. Applicability of polar organic compound integrative samplers for monitoring pesticides in groundwater.

    Science.gov (United States)

    Berho, Catherine; Togola, Anne; Coureau, Charlotte; Ghestem, Jean-Philippe; Amalric, Laurence

    2013-08-01

    Polar organic chemical integrative samplers (POCISs) for the monitoring of polar pesticides in groundwater were tested on two sites in order to evaluate their applicability by comparison with the spot-sampling approach. This preliminary study shows that, as in surface water, POCIS is a useful tool, especially for the screening of substances at low concentration levels that are not detected by laboratory analysis of spot samples. For quantitative results, a rough estimation is obtained. The challenge is now to define the required water-flow conditions for a relevant quantification of pesticides in groundwater and to establish more representative sampling rates for groundwater.

  13. Variant of a volume-of-fluid method for surface tension-dominant two-phase flows

    Indian Academy of Sciences (India)

    G Biswas

    2013-12-01

    The capabilities of the volume-of-fluid method for the calculation of surface tension-dominant two-phase flows are explained. The accurate calculation of the interface remains a problem for the volume-of-fluid method if the density ratios of the fluids in different phases are high. The simulations of bubble growth is performed in water at near critical pressure for different degrees of superheat using combined levelset and volume-of fluid (CLSVOF) method. The effect of superheat on the frequency of bubble formation was analyzed. A deviation from the periodic bubble release is observed in the case of superheat of 20 K in water. The vapor-jet-like columnar structure is observed. Effect of heat flux on the slender vapor column has also been explained.

  14. 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.

  15. Properties of the Affine Invariant Ensemble Sampler in high dimensions

    CERN Document Server

    Huijser, David; Brewer, Brendon J

    2015-01-01

    We present theoretical and practical properties of the affine-invariant ensemble sampler Markov chain Monte Carlo method. In high dimensions the affine-invariant ensemble sampler shows unusual and undesirable properties. We demonstrate this with an $n$-dimensional correlated Gaussian toy problem with a known mean and covariance structure, and analyse the burn-in period. The burn-in period seems to be short, however upon closer inspection we discover the mean and the variance of the target distribution do not match the expected, known values. This problem becomes greater as $n$ increases. We therefore conclude that the affine-invariant ensemble sampler should be used with caution in high dimensional problems. We also present some theoretical results explaining this behaviour.

  16. INSTRUCTIONS FOR OPERATING LBL FORMALDEHYDE SAMPLER

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-09-01

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

  17. IDSAC-IUCAA digital sampler array controller

    Science.gov (United States)

    Chattopadhyay, Sabyasachi; Chordia, Pravin; Ramaprakash, A. N.; Burse, Mahesh P.; Joshi, Bhushan; Chillal, Kalpesh

    2016-07-01

    In order to run the large format detector arrays and mosaics that are required by most astronomical instruments, readout electronic controllers are required which can process multiple CCD outputs simultaneously at high speeds and low noise levels. These CCD controllers need to be modular and configurable, should be able to run multiple detector types to cater to a wide variety of requirements. IUCAA Digital Sampler Array Controller (IDSAC), is a generic CCD Controller based on a fully scalable architecture which is adequately flexible and powerful enough to control a wide variety of detectors used in ground based astronomy. The controller has a modular backplane architecture that consists of Single Board Controller Cards (SBCs) and can control up to 5 CCDs (mosaic or independent). Each Single Board Controller (SBC) has all the resources to a run Single large format CCD having up to four outputs. All SBCs are identical and are easily interchangeable without needing any reconfiguration. A four channel video processor on each SBC can process up to four output CCDs with or without dummy outputs at 0.5 Megapixels/Sec/Channel with 16 bit resolution. Each SBC has a USB 2.0 interface which can be connected to a host computer via optional USB to Fibre converters. The SBC uses a reconfigurable hardware (FPGA) as a Master Controller. IDSAC offers Digital Correlated Double Sampling (DCDS) to eliminate thermal kTC noise. CDS performed in Digital domain (DCDS) has several advantages over its analog counterpart, such as - less electronics, faster readout and easier post processing. It is also flexible with sampling rate and pixel throughput while maintaining the core circuit topology intact. Noise characterization of the IDSAC CDS signal chain has been performed by analytical modelling and practical measurements. Various types of noise such as white, pink, power supply, bias etc. has been considered while creating an analytical noise model tool to predict noise of a controller

  18. Effects of diluents on soot surface temperature and volume fraction in diluted ethylene diffusion flames at pressure

    KAUST Repository

    Kailasanathan, Ranjith Kumar Abhinavam

    2014-05-20

    Soot surface temperature and volume fraction are measured in ethylene/air coflowing laminar diffusion flames at high pressures, diluted with one of four diluents (argon, helium, nitrogen, and carbon dioxide) using a two-color technique. Both temperature and soot measurements presented are line-of-sight averages. The results aid in understanding the kinetic and thermodynamic behavior of the soot formation and oxidation chemistry with changes in diluents, ultimately leading to possible methods of reducing soot emission from practical combustion hardware. The diluted fuel and coflow exit velocities (top-hat profiles) were matched at all pressures to minimize shear effects. In addition to the velocity-matched flow rates, the mass fluxes were held constant for all pressures. Addition of a diluent has a pronounced effect on both the soot surface temperature and volume fraction, with the helium diluted flame yielding the maximum and carbon dioxide diluted flame yielding minimum soot surface temperature and volume fraction. At low pressures, peak soot volume fraction exists at the tip of the flame, and with an increase in pressure, the location shifts lower to the wings of the flame. Due to the very high diffusivity of helium, significantly higher temperature and volume fraction are measured and explained. Carbon dioxide has the most dramatic soot suppression effect. By comparing the soot yield with previously measured soot precursor concentrations in the same flame, it is clear that the lower soot yield is a result of enhanced oxidation rates rather than a reduction in precursor formation. Copyright © 2014 Taylor & Francis Group, LLC.

  19. Monitoring of jökulhlaups and element fluxes in proglacial Icelandic rivers using osmotic samplers

    Science.gov (United States)

    Jones, Morgan T.; Gałeczka, Iwona M.; Gkritzalis-Papadopoulos, Athanasios; Palmer, Martin R.; Mowlem, Matthew C.; Vogfjörð, Kristín; Jónsson, Þorsteinn; Gislason, Sigurður R.

    2015-01-01

    The quantification of volatile emissions from volcanoes is an integral part of understanding magmatic systems, with the exsolution and extent of volcanic degassing having a large impact on the nature of an eruption. Measurements of volatiles have traditionally focused on gas emissions into the atmosphere, but volatiles can also become dissolved in proximal water bodies en route to the surface. Thus the monitoring of rivers draining active volcanic areas can provide insights to identifying changes in activity. This process is particularly important for sub-glacial volcanoes in Iceland, where much of the volatile release is transported within glacial outbreak floods, termed jökulhlaups. Monitoring and characterising these phenomena is hampered by the dependence on spot sampling of stochastic events under challenging field conditions, which often leads to bias in the collected data. A recent technological advance is the osmotic sampler, an electricity-free pump that continuously collects water that can subsequently be divided into time-averaged samples. This technique allows for continued and unsupervised deployment of a sampler for weeks to months, representing a cost-efficient form of chemical monitoring. In this study we deployed osmotic samplers in two rivers in southern Iceland. Skálm is a proglacial river from Mýrdalsjökull glacier and Katla volcano, while Skaftá is a larger drainage system from the western part of Vatnajökull glacier. Both rivers are prone to jökulhlaups from geothermal and volcanic sources, and a small jökulhlaup of geothermal origin occurred during the second deployment in Skaftá in January 2014. The two deployments show that osmotic samplers are capable of delivering accurate chemical data in turbulent conditions for several key elements. Total dissolved fluxes for the deployment at Skaftá are calculated to be Na = 9.9 tonnes/day, Mg = 10.5 t/d, Si = 34.7 t/d, Cl = 11.0 t/d, Ca = 31.6 t/d, DIC = 50.8 t/d, and SO4 = 28.3 t/d, with

  20. Multifractal parametrization for the volume of space forms on surfaces of Zn x Cd1- x Te-Si(111) heterocompositions and estimating the energy of a surface with fractal structure

    Science.gov (United States)

    Moskvin, P. P.; Krizhanovskii, V. B.; Rashkovetskii, L. V.; Vuichik, N. V.

    2016-05-01

    Multifractal (MF) analysis is used to describe the volume of space forms on the surfaces of structures in the solid solution of a Zn x Cd1- x Te-Si(111) substrate. AFM images of film surfaces have been are used for MF analysis. The parameters of MF spectra are determined for the distribution of volume of surface nanoforms. Based on the formal approach and data on the parameters of the fractal state for the volume and surfaces of nanoforms, an equation is proposed that considers the contribution from the fractal structure of the surface to its surface energy. The behavior of the system's surface energy, depending on fractal parameters that describe states of the volume and surfaces of nanoforms is discussed.

  1. Influence of SHI upon nanohole free volume and micro scale level surface modifications of polyethyleneterephthalate polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rajesh, E-mail: rajeshkumaripu@gmail.com; Singh, Paramjit

    2015-05-15

    Highlights: • Ion irradiation of PET polymer (used for gas separation applications) for structural, optical, chemical, surface and free volume studies. • The amorphization and decrease of the band gap energy after ions irradiation. • The value of R increased after ion irradiation due to the expansion of the polymeric chains and increase of the size of cavities. • Increase in the surface roughness creating the site of track formation. - Abstract: Topographic micro scale and in-depth nano scale level modifications of polymeric materials play an important role in engineering their physical and chemical properties. Polyethylene terephthalate (PET) is an important class of semi-crystalline polymers used for gas separation properties. The gas diffusion and permeability parameters are directly related to the free volume fractions and the hole distributions. The controlled and precise ion beam irradiation can be used to induce surface and in-depth modifications in the properties of the polymers which help in modifying free volume holes and their distributions. In the present study, the investigation of free volume (nano scale level) and surface (micro scale level) properties of PET polymeric thin films after SHI treatment were employed by means of positron annihilation lifetime spectroscopy (PALS) and atomic force microscopy (AFM), respectively. The PET thin films were irradiated by 50 MeV lithium ions as a function of ion fluence. The value of hole radius (R) and intensity (I{sub 3}) of o-Ps were observed to be increased after ion beam treatment. The further analyses were employed to calculate the free volume and fractional free volume of holes from the obtained values of R and I{sub 3}. The AFM studies reveal the surface modifications of the irradiated polymer films. The structural, optical and chemical properties were investigated by X-ray diffraction (XRD), UV–visible (UV–vis) and Fourier transform infrared (FTIR) spectrophotometry. Different parameters

  2. Pulsed second order field NMR for real time PGSE and single-shot surface to volume ratio measurements.

    Science.gov (United States)

    Kittler, W C; Obruchkov, S; Galvosas, P; Hunter, M W

    2014-10-01

    Pulsed field gradient nuclear magnetic resonance provides a powerful tool for the measurement of particle diffusion and mobility. When these particles are contained in a porous medium, the diffusive process is influenced by the pore boundaries, and their effect on diffusion measurements provides information about the pore space. The acquisition of the apparent diffusion coefficient and its dependence on time, in the short time limit, reveals the surface to volume ratio of the porous medium, and in the long time limit, its tortuosity. With conventional pulsed field gradient techniques, processes where pore boundaries are evolving on the sub-second time scale cannot be resolved. Using pulsed second order magnetic fields in conjunction with one-dimensional imaging and the pulse sequence Difftrain, this paper presents a proof of concept for the first ever real time single-shot surface to volume NMR measurement.

  3. Pulsed second order field NMR for real time PGSE and single-shot surface to volume ratio measurements

    Science.gov (United States)

    Kittler, W. C.; Obruchkov, S.; Galvosas, P.; Hunter, M. W.

    2014-10-01

    Pulsed field gradient nuclear magnetic resonance provides a powerful tool for the measurement of particle diffusion and mobility. When these particles are contained in a porous medium, the diffusive process is influenced by the pore boundaries, and their effect on diffusion measurements provides information about the pore space. The acquisition of the apparent diffusion coefficient and its dependence on time, in the short time limit, reveals the surface to volume ratio of the porous medium, and in the long time limit, its tortuosity. With conventional pulsed field gradient techniques, processes where pore boundaries are evolving on the sub-second time scale cannot be resolved. Using pulsed second order magnetic fields in conjunction with one-dimensional imaging and the pulse sequence Difftrain, this paper presents a proof of concept for the first ever real time single-shot surface to volume NMR measurement.

  4. INNOVATIVE TECHNOLOGY EVALUATION REPORT, SEDIMENT SAMPLING TECHNOLOGY, ART'S MANUFACTURING, SPLIT CORE SAMPLER FOR SUBMERGED SEDIMENTS

    Science.gov (United States)

    The Split Core Sampler for Submerged Sediments (Split Core Sampler) designed and fabricated by Arts Manufacturing & Supply, Inc., was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation Program in April and May 1999 at ...

  5. 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...

  6. Idealized Shale Sorption Isotherm Measurements to Determine Pore Volume, Pore Size Distribution, and Surface Area

    Science.gov (United States)

    Holmes, R.; Wang, B.; Aljama, H.; Rupp, E.; Wilcox, J.

    2014-12-01

    One method for mitigating the impacts of anthropogenic CO2-related climate change is the sequestration of CO2 in depleted gas and oil reservoirs, including shale. The accurate characterization of the heterogeneous material properties of shale, including pore volume, surface area, pore size distributions (PSDs) and composition is needed to understand the interaction of CO2 with shale. Idealized powdered shale sorption isotherms were created by varying incremental amounts of four essential components by weight. The first two components, organic carbon and clay, have been shown to be the most important components for CO2 uptake in shales. Organic carbon was represented by kerogen isolated from a Silurian shale, and clay groups were represented by illite from the Green River shale formation. The rest of the idealized shale was composed of equal parts by weight of SiO2 to represent quartz and CaCO3 to represent carbonate components. Baltic, Eagle Ford, and Barnett shale sorption measurements were used to validate the idealized samples. The idealized and validation shale sorption isotherms were measured volumetrically using low pressure N2 (77K) and CO2 (273K) adsorbates on a Quantachrome Autosorb IQ2. Gravimetric isotherms were also produced for a subset of these samples using CO2 and CH4adsorbates under subsurface temperature and pressure conditions using a Rubotherm magnetic suspension balance. Preliminary analyses were inconclusive in validating the idealized samples. This could be a result of conflicting reports of total organic carbon (TOC) content in each sample, a problem stemming from the heterogeneity of the samples and different techniques used for measuring TOC content. The TOC content of the validation samples (Eagle Ford and Barnett) was measured by Rock-Eval pyrolysis at Weatherford Laboratories, while the TOC content in the Baltic validation samples was determined by LECO TOC. Development of a uniform process for measuring TOC in the validation samples is

  7. 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

  8. Preparation of High Surface Area, Large Pore Volume Alumina by Using β-Cyclodextrin as a Non-surfactant Template

    Institute of Scientific and Technical Information of China (English)

    Lai Jun WANG; Ming Fen WEN; Yu Shan LI; Dong YANG; Jing CHEN; Chong Li SONG

    2006-01-01

    A series of alumina samples were prepared using β-cyclodextrin as the non-surfactant template. These samples were characterized by XRD, BET and TEM. The results showed that the alumina samples prepared using β-cyclodextrin template had the higher surface areas (124-484 m2/g), larger pore volumes (0.7-1.27 mL/g) and more thermal stability than samples prepared without using β-cyclodextrin.

  9. Volume Continuation of potential fields from the minimum-length solution: An optimal tool for continuation through general surfaces

    Science.gov (United States)

    Mastellone, Daniela; Fedi, Maurizio; Ialongo, Simone; Paoletti, Valeria

    2014-12-01

    Many methods have been used to upward continue potential field data. Most techniques employ the Fast Fourier transform, which is an accurate, quick way to compute level-to-level upward continuation or spatially varying scale filters for level-to-draped surfaces. We here propose a new continuation approach based on the minimum-length solution of the inverse potential field problem, which we call Volume Continuation (VOCO). For real data the VOCO is obtained as the regularized solution to the Tikhonov problem. We tested our method on several synthetic examples involving all types of upward continuation and downward continuation (level-to-level, level-to-draped, draped-to-level, draped-to-draped). We also employed the technique to upward continue to a constant height (2500 m a.s.l.), the high-resolution draped aeromagnetic data of the Ischia Island in Southern Italy. We found that, on the average, they are consistent with the aeromagnetic regional data measured at the same altitude. The main feature of our method is that it does not only provide continued data over a specified surface, but it yields a volume of upward continuation. For example, the continued data refers to a volume and thus, any surface may be easily picked up within the volume to get upward continuation to different surfaces. This approach, based on inversion of the measured data, tends to be especially advantageous over the classical techniques when dealing with draped-to-level upward continuation. It is also useful to obtain a more stable downward continuation and to continue noisy data. The inversion procedure involved in the method implies moderate computational costs, which are well compensated by getting a 3D set of upward continued data to achieve high quality results.

  10. Volume labeling with Alexa Fluor dyes and surface functionalization of highly sensitive fluorescent silica (SiO2) nanoparticles

    Science.gov (United States)

    Wang, Wei; Nallathamby, Prakash D.; Foster, Carmen M.; Morrell-Falvey, Jennifer L.; Mortensen, Ninell P.; Doktycz, Mitchel J.; Gu, Baohua; Retterer, Scott T.

    2013-10-01

    A new synthesis approach is described that allows the direct incorporation of fluorescent labels into the volume or body of SiO2 nanoparticles. In this process, fluorescent Alexa Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and a polydispersity of Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and a polydispersity of <15%. In comparison with conventional surface tagged particles created by post-synthesis modification, this process maintains the physical and surface chemical properties that have the most pronounced effect on colloidal stability and interactions with their surroundings. These volume-labeled nanoparticles have proven to be extremely robust, showing excellent signal strength, negligible photobleaching, and minimal loss of functional organic components. The native or ``free'' surface of the volume-labeled particles can be altered to achieve a specific surface functionality without altering fluorescence. Their utility was demonstrated for visualizing the association of surface-modified fluorescent particles

  11. The Surface-to-volume Ratio of the Synthesis Reactor Vessel Governing the Low Temperature Crystallization of ZSM-5

    Directory of Open Access Journals (Sweden)

    Ana Hidayati Mukaromah

    2016-12-01

    Full Text Available Zeolite ZSM-5 is one of major catalysts in petroleum and fine-chemical industries. The synthesis of zeolite ZSM-5 is usually carried out at high temperature above 100 °C using the immense amount of organic structure-directing agents (OSDA. It is interesting to note that fine-tuning the initial gel mixture can be used to enhance the typical slow crystallization rate of ZSM-5. Herein, we report the effect of the surface-to-volume ratio of the reactor vessel to the crystallization of ZSM-5 at low temperature. The surface-to-volume ratio of the reactor vessel could influence the heat-transfer during the synthesis which further governed the crystallization of ZSM-5. It was found that the higher the surface-to-volume of the reactor, the more crystalline of the resulting products. The product with the highest crystallinity exhibited a nearly-spherical morphology composed of smaller ZSM-5 crystallites. This phenomenon allowed the presence of inter-crystallite mesopores which is an advantage for the catalytic reaction using bulky molecules.

  12. A σ-coordinate model for 3D free-surface flows using an unstructured finite-volume technique

    Science.gov (United States)

    Uh Zapata, Miguel

    2016-11-01

    The aim of this work is to develop a numerical solution of three-dimensional free-surface flows using a σ-coordinate model, a projection method and an unstructured finite-volume technique. The coordinate transformation is used in order to overcome difficulties arising from free surface elevation and irregular geometry. The projection method consists to combine the momentum and continuity equations in order to establish a Poisson-type equation for the non-hydrostatic pressure. A cell-centered finite volume method with a triangular mesh in the horizontal direction is used to simulate the flows with free-surfaces, in which the average values of conserved variables are stored at the centre of each element. A parallel algorithm is also presented for the finite volume discretization of the 3D Navier-Stokes equations. The proposed parallel method is formulated by using a multi-color SOR method, a block domain decomposition and interprocessor data communication techniques with Message Passing Interface. The model has been validated by several benchmarks which numerical simulations are in good agreement with the corresponding analytical and existing experimental results.

  13. Validation of a diffusive sampler for NO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Hagenbjoerk-Gustafsson, Annika; Lindahl, Roger; Levin, Jan-Olof [National Inst. for Working Life, Dept. of Chemistry, Umeaa (Sweden); Karlsson, Doris [Umeaa Univ., Dept. of Environmental Health, Umeaa (Sweden)

    1999-08-01

    A diffusive sampler for NO{sub 2}, Willems badge, was validated in laboratory experiments and field tests. The collecting reagent for NO{sub 2} in the sampler is triethanolamine, and the analysis is based on a modified colorimetric method, the Saltzman method. The analysis was performed by a flow injection analysis (FIA) technique. The sampling rate for the sampler was determined to be 40.0 ml min {sup -1}. There was no effect of NO{sub 2} concentration or relative humidity on sampling rate, and the influence of sampling time was found to be small. The detection limit was 4 {mu}g m {sup -3} for a 24 h sample. The capacity is high enough to allow sampling of 150 {mu}g m {sup -3} for 7 days, which is twice the recommended Swedish short-term (24h) guideline value as a 98-percentile over 6 months. In field tests, the sampler performed well, even at wind speeds higher than 2 m s{sup -1}, and at low temperatures. The overall uncertainty of the method was 24%. The sensitivity and capacity of the method also make it suitable for personal sampling for 2-8 h in working environments. (Author)

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    1999-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ziada, H.H.

    1995-03-30

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

  19. Calculating the Diffusive Flux of Persistent Organic Pollutants between Sediments and the Water Column on the Palos Verdes Shelf Superfund Site using Polymeric Passive Samplers

    Science.gov (United States)

    Passive samplers were used to determine water concentrations of persistent organic pollutants (POPs) in the surface sediments and near-bottom water of a marine Superfund site on the Palos Verdes Shelf, California, USA. Measured concentrations in the porewater and water column at...

  20. Performance of the Button Personal Inhalable Sampler for the measurement of outdoor aeroallergens

    Science.gov (United States)

    Adhikari, Atin; Martuzevicius, Dainius; Reponen, Tiina; Grinshpun, Sergey A.; Cho, Seung-Hyun; Sivasubramani, Satheesh K.; Zhong, Wei; Levin, Linda; Kelley, Anna L.; St. Clair, Harry G.; LeMasters, Grace

    No personal aerosol sampler has been evaluated for monitoring aeroallergens in outdoor field conditions and compared to conventional stationary aerobiological samplers. Recently developed Button Personal Inhalable Aerosol Sampler has demonstrated high sampling efficiency for non-biological particles and low sensitivity to the wind direction and velocity. The aim of the present study was to evaluate the Button Sampler for the measurement of outdoor pollen grains and fungal spores side-by-side with the widely used Rotorod Sampler. The sampling was performed for 8 months (spring, summer and fall) at a monitoring station on the roof of a two-storied office building located in the center of the city of Cincinnati. Two identical Button Samplers, one oriented towards the most prevalent wind and the other towards the opposite wind and a Rotorod Sampler were placed side-by-side. The total fungal spore concentration ranged from 129 to 12,980 spores m -3 (number per cubic meter of air) and the total pollen concentration from 4 to 4536 pollen m -3. The fungal spore concentrations obtained with the two Button Samplers correlated well ( r=0.95; pbiological aerosol particles, which demonstrated a low wind dependence of the performance of the Button Sampler compared to other samplers. The Button Sampler's inlet efficiency was found to be more dependent on wind direction when sampling larger sized Pinaceae pollen grains (aerodynamic diameter ≈65 μm). Compared to Rotorod, both Button Samplers measured significantly higher total fungal spore concentrations. For total pollen count, the Button Sampler facing the prevalent wind showed concentrations levels comparable to that of the Rotorod, but the Button Sampler oriented opposite to the prevalent wind demonstrated lower concentration levels. Overall, it was concluded that the Button Sampler is efficient for the personal sampling of outdoor aeroallergens, and is especially beneficial for aeroallergens of small particle size.

  1. On the effect of standard PFEM remeshing on volume conservation in free-surface fluid flow problems

    Science.gov (United States)

    Franci, Alessandro; Cremonesi, Massimiliano

    2017-07-01

    The aim of this work is to analyze the remeshing procedure used in the particle finite element method (PFEM) and to investigate how this operation may affect the numerical results. The PFEM remeshing algorithm combines the Delaunay triangulation and the Alpha Shape method to guarantee a good quality of the Lagrangian mesh also in large deformation processes. However, this strategy may lead to local variations of the topology that may cause an artificial change of the global volume. The issue of volume conservation is here studied in detail. An accurate description of all the situations that may induce a volume variation during the PFEM regeneration of the mesh is provided. Moreover, the crucial role of the parameter α used in the Alpha Shape method is highlighted and a range of values of α for which the differences between the numerical results are negligible, is found. Furthermore, it is shown that the variation of volume induced by the remeshing reduces by refining the mesh. This check of convergence is of paramount importance for the reliability of the PFEM. The study is carried out for 2D free-surface fluid dynamics problems, however the conclusions can be extended to 3D and to all those problems characterized by significant variations of internal and external boundaries.

  2. Investigation of spin-reorientation phase transitions at surface and in volume of alpha-Fe sub 2 O sub 3 monocrystals

    CERN Document Server

    Kamzin, A S

    2002-01-01

    The magnetic structure of the surface layer and volume and the processes, observed by the spin-reorientation phase transition (SRPT), are studied in the direct comparison of the properties of the thin surface layer and the volume of the hematite (alpha-Fe sub 2 O sub 3) macroscopic crystals. The method of simultaneous gamma, X-ray and electron Moessbauer spectroscopy was used in the studies. The direct data on the existence of the transition layer on the hematite crystals surface are obtained. It is established, that the Morin-type SRPT in the sample volume occurs by a jump (the first-order phase transition). The SRPT in the surface layer as well as in the crystal volume is accompanied by formation of the intermediate state, wherein the low- and high-temperature phases coexist. The obtained experimental data on the SRPT mechanism in the surface layer agree well with the conclusions of the phenomenological theory

  3. Verification and transfer of thermal pollution model. Volume 2: User's manual for 3-dimensional free-surface model

    Science.gov (United States)

    Lee, S. S.; Sengupta, S.; Tuann, S. Y.; Lee, C. R.

    1982-01-01

    The six-volume report: describes the theory of a three-dimensional (3-D) mathematical thermal discharge model and a related one-dimensional (1-D) model, includes model verification at two sites, and provides a separate user's manual for each model. The 3-D model has two forms: free surface and rigid lid. The former, verified at Anclote Anchorage (FL), allows a free air/water interface and is suited for significant surface wave heights compared to mean water depth; e.g., estuaries and coastal regions. The latter, verified at Lake Keowee (SC), is suited for small surface wave heights compared to depth. These models allow computation of time-dependent velocity and temperature fields for given initial conditions and time-varying boundary conditions.

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

    Science.gov (United States)

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

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

  5. Stick-Jump (SJ) Evaporation of Strongly Pinned Nanoliter Volume Sessile Water Droplets on Quick Drying, Micropatterned Surfaces.

    Science.gov (United States)

    Debuisson, Damien; Merlen, Alain; Senez, Vincent; Arscott, Steve

    2016-03-22

    We present an experimental study of stick-jump (SJ) evaporation of strongly pinned nanoliter volume sessile water droplets drying on micropatterned surfaces. The evaporation is studied on surfaces composed of photolithographically micropatterned negative photoresist (SU-8). The micropatterning of the SU-8 enables circular, smooth, trough-like features to be formed which causes a very strong pinning of the three phase (liquid-vapor-solid) contact line of an evaporating droplet. This is ideal for studying SJ evaporation as it contains sequential constant contact radius (CCR) evaporation phases during droplet evaporation. The evaporation was studied in nonconfined conditions, and forced convection was not used. Micropatterned concentric circles were defined having an initial radius of 1000 μm decreasing by a spacing ranging from 500 to 50 μm. The droplet evaporates, successively pinning and depinning from circle to circle. For each pinning radius, the droplet contact angle and volume are observed to decrease quasi-linearly with time. The experimental average evaporation rates were found to decrease with decreasing pining radii. In contrast, the experimental average evaporation flux is found to increase with decreasing droplet radii. The data also demonstrate the influence of the initial contact angle on evaporation rate and flux. The data indicate that the total evaporation time of a droplet depends on the specific micropattern spacing and that the total evaporation time on micropatterned surfaces is always less than on flat, homogeneous surfaces. Although the surface patterning is observed to have little effect on the average droplet flux-indicating that the underlying evaporation physics is not significantly changed by the patterning-the total evaporation time is considerably modified by patterning, up to a factor or almost 2 compared to evaporation on a flat, homogeneous surface. The closely spaced concentric circle pinning maintains a large droplet radius and

  6. Profiling river surface velocities and volume flow estimation with bistatic UHF RiverSonde radar

    Science.gov (United States)

    Barrick, D.; Teague, C.; Lilleboe, P.; Cheng, R.; Gartner, J.; ,

    2003-01-01

    From the velocity profiles across the river, estimates of total volume flow for the four methods were calculated based on a knowledge of the bottom depth vs position across the river. It was found that the flow comparisons for the American River were much closer, within 2% of each other among all of the methods. Sources of positional biases and anomalies in the RiverSonde measurement patterns along the river were identified and discussed.

  7. Surface and volume characterization of TiO{sub 2} nanomaterials by {sup 44}Ti time differential perturbed angular correlation

    Energy Technology Data Exchange (ETDEWEB)

    Butz, T. [Leipzig Univ. (Germany). Faculty of Physics and Earth Sciences

    2012-07-01

    Various TiO{sub 2} nanomaterials with primary particle sizes well below 10 nm and TiO{sub 2} nanotubes with the anatase structure were studied via the nuclear quadrupole interaction (NQI) of {sup 44}Ti(EC){sup 44}Sc by time differential perturbed angular correlation. In general two different NQIs were observed, the lower one attributed to the volume fraction because of the similarity to bulk values and the higher one to probes closest to the surface. Rather broad distributions of the strength of the interaction were observed which were different for nominally identical particles, contrary to the axial symmetry which is preserved to a very large extent. These distributions are interpreted as disorder arising from surface tension. These complications affect the interaction between these nanomaterials with biological systems and the environment and render toxicological assessments problematic. Dissolution studies in a synthetic body fluid mimicking blood plasma at 37 C for 4 weeks exhibited a very low solubility, but surprisingly slight changes in the volume fraction, probably due to surface adsorbates. (orig.)

  8. The properties of a large volume-limited sample of face-on low surface brightness disk galaxies

    Institute of Scientific and Technical Information of China (English)

    Guo-Hu Zhong; Yan-Chun Liang; Feng-Shan Liu; Francois Hammer; Karen Disseau; Li-Cai Deng

    2012-01-01

    We select a large volume-limited sample of low surface brightness galaxies (LSBGs,2021) to investigate in detail their statistical properties and their differences from high surface brightness galaxies (HSBGs,3639).The distributions of stellar masses of LSBGs and HSBGs are nearly the same and they have the same median values.Thus this volume-limited sample has good completeness and is further removed from the effect of stellar masses on their other properties when we compare LSBGs to HSBGs.We found that LSBGs tend to have lower stellar metallicities and lower effective dust attenuations,indicating that they have lower dust than HSBGs.The LSBGs have relatively higher stellar mass-to-light ratios,higher gas fractions,lower star forming rates (SFRs),and lower specific SFRs than HSBGs.Moreover,with the decreasing surface brightness,gas fraction increases,but the SFRs and specific SFRs decrease rapidly for the sample galaxies.This could mean that the star formation histories between LSBGs and HSBGs are different,and HSBGs may have stronger star forming activities than LSBGs.

  9. Free Energies of Solvation with Surface, Volume, and Local Electrostatic Effects and Atomic Surface Tensions to Represent the First Solvation Shell.

    Science.gov (United States)

    Liu, Junjun; Kelly, Casey P; Goren, Alan C; Marenich, Aleksandr V; Cramer, Christopher J; Truhlar, Donald G; Zhan, Chang-Guo

    2010-03-04

    Building on the SVPE (surface and volume polarization for electrostatics) model for electrostatic contributions to the free energy of solvation with explicit consideration of both surface and volume polarization effects, on the SMx approach to including first-solvation-shell contributions, and on the linear relationship between the electric field and short-range electrostatic contributions found by Chipman, we have developed a new method for computing absolute aqueous solvation free energies by combining the SVPE method with semiempirical terms that account for effects beyond bulk electrostatics. The new method is called SMVLE, and the elements it contains are denoted by SVPE-CDSL where SVPE denotes accounting for bulk electrostatic interactions between solute and solvent with both surface and volume contributions, CDS denotes the inclusion of solvent cavitation, changes in dispersion energy, and possible changes in local solvent structure by a semiempirical term utilizing geometry-dependent atomic surface tensions as implemented in SMx models, and L represents the local electrostatic effect derived from the outward-directed normal electric field on the cavity surface. The semiempirical CDS and L terms together represent the deviation of short-range contributions to the free energy of solvation from those accounted for by the SVPE term based on the bulk solvent dielectric constant. A solute training set containing a broad range of molecules used previously in the development of SM6 is used here for SMVLE model calibration. The aqueous solvation free energies predicted by the parameterized SMVLE model correlate exceedingly well with experimental values. The square of the correlation coefficient is 0.9949 and the slope is 1.0079. Comparison of the final SMVLE model against the earlier SMx solvation model shows that the parameterized SMVLE model not only yields good accuracy for neutrals but also significantly increases the accuracy for ions, making it the best

  10. Multiplicative models of analysis : a description and the use in analysing accident ratios as a function of hourly traffic volume and road-surface skidding resistance.

    NARCIS (Netherlands)

    Oppe, S.

    1977-01-01

    Accident ratios are analysed with regard to the variables road surface skidding resistance and hourly traffic volume. It is concluded that the multiplicative model describes the data better than the additive model. Moreover that there is no interaction between skidding resistance and traffic volume

  11. Assessing the influence of meteorological parameters on the performance of polyurethane foam-based passive air samplers.

    Science.gov (United States)

    Klánová, Jana; Eupr, Pavel; Kohoutek, Jirí; Harner, Tom

    2008-01-15

    Polyurethane foam (PUF) disk passive air samplers were evaluated under field conditionsto assessthe effect of temperature and wind speed on the sampling rate for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs). Passive samples integrated over 28-day periods were compared to high-volume air samples collected for 24 h, every 7 days. This provided a large data set of 42 passive sampling events and 168 high-volume samples over a 3-year period, starting in October 2003. Average PUF disk sampling rates for gas-phase chemicals was approximately 7 m3 d(-1) and comparable to previous reports. The high molecular weight PAHs, which are mainly particle-bound, experienced much lower sampling rates of approximately 0.7 m3 d(-1). This small rate was attributed to the ability of the sampling chamber to filter out coarse particles with only the fine/ultrafine fraction capable of penetration and collection on the PUF disk. Passive sampler-derived data were converted to equivalent air volumes (V(EQ), m3) using the high-volume air measurement results. Correlations of V(EQ) against meteorological data collected on-site yielded different behavior for gas- and particle-associated compounds. For gas-phase chemicals, sampling rates varied by about a factor of 2 with temperature and wind speed. The higher sampling rates at colder temperatures were explained bythe wind effecton sampling rates. Temperature and wind were strongly correlated with the greatest winds at coldertemperatures. Mainly particle-phase compounds (namely, the high molecular weight PAHs) had more variable sampling rates. Sampling rates increased greatly atwarmertemperatures as the high molecular weight PAH burden was shifted toward the gas phase and subject to higher gas-phase sampling rates. At colder temperatures, sampling rates were reduced as the partitioning of the high molecular weight PAHs was shifted toward the particle phase. The observed wind effect

  12. Surface Cleaning by Glow Discharge in High-Volume Gas Flow

    Science.gov (United States)

    1976-04-07

    was used with a #25 size hypodermic needle the results are shown in Table 2. A slightly smaller drop was obtained when using the same size needle coated...small to measure, indicates a surface free of both water and of substances which are hydrophobic. The theory of the significance of the small contact...and its diameter when spread out over the surface of the clean specimen. The experiment data to test the following theory , was accumulated by measuring

  13. Program EAGLE User’s Manual. Volume 2. Surface Generation Code

    Science.gov (United States)

    1988-09-01

    252 APPENDIX H NEWTO~N ITERATION FOR INTERSECTION .. .................. 2514 HFFERENCS . ........................ ..... 257 xi/ xii (Blank) NTrRODUCTION...34COMBTNE" will store a tabla of contents of the combined file if CONTENT="YES". This table consists of the COREOUT num- ber and the surface(CURVE...surfaces are developed as follows: (The code notation follows closely that used here.) 1. Sphere xII r(e,q) - constant 2. Ellipsoid x Y E The equation for

  14. In-Situ Ultrasonic Characterization of Patterns of Sediment Surface Roughness and Subsurface Volume Inhomogeneities

    Science.gov (United States)

    2016-06-07

    successfully images surface and sub-surface biogenic structure non-invasively in the laboratory (ultrasound) and convert the technology for use in...5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of Rhode Island,Graduate School of Oceanography,Narragansett...RI,02882 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 11

  15. Simulation of dissolution in porous media in three dimensions with lattice Boltzmann, finite-volume, and surface-rescaling methods

    Science.gov (United States)

    Gray, F.; Cen, J.; Boek, E. S.

    2016-10-01

    We present a pore-scale dissolution model for the simulation of reactive transport in complex porous media such as those encountered in carbon-storage injection processes. We couple a lattice Boltzmann model for flow calculation with a finite-volume method for solving chemical transport equations, and allow the computational grid to change as mineral surfaces are dissolved according to first-order reaction kinetics. We appraise this scheme for use with high Péclet number flows in three-dimensional geometries and show how the popular first-order convection scheme is affected by severe numerical diffusion when grid Péclet numbers exceed unity, and confirm that this can be overcome relatively easily by using a second-order method in conjunction with a flux-limiter function. We then propose a surface rescaling method which uses parabolic elements to counteract errors in surface area exposed by the Cartesian grid and avoid the use of more complex embedded surface methods when surface reaction kinetics are incorporated. Finally, we compute dissolution in an image of a real porous limestone rock sample injected with HCl for different Péclet numbers and obtain dissolution patterns in concordance with theory and experimental observation. A low injection flow rate was shown to lead to erosion of the pore space concentrated at the face of the rock, whereas a high flow rate leads to wormhole formation.

  16. Passive samplers for chemical substance monitoring and associated toxicity assessment in water.

    Science.gov (United States)

    Tapie, N; Devier, M H; Soulier, C; Creusot, N; Le Menach, K; Aït-Aïssa, S; Vrana, B; Budzinski, H

    2011-01-01

    The European legislation, and in particular the Water Framework Directive requires the development of cost efficient monitoring tools that can provide the required information for the assessment of water contamination. Passive sampling methods represent one of the novel tools that have a potential to be used in various regulatory monitoring programmes aimed at assessing the levels of chemical pollutants. These methods are particularly interesting for sampling polar organic pollutants in water because they provide representative information of the water quality over extended time periods (days to weeks) in environments with fluctuating contaminant concentrations. This is achieved by integrative sampling of pollutants over the whole sampler deployment period. These tools can be coupled to toxicity testing using bioassays that give information on toxic and ecotoxic hazards associated to substances that are present, these substances being identified or not. In this study the polar organic chemical integrative sampler (POCIS) was used in surface water to evaluate the water contamination by polar organic compounds and their potential toxicity.

  17. Do skeletal cephalometric characteristics correlate with condylar volume, surface and shape? A 3D analysis

    OpenAIRE

    Saccucci Matteo; Polimeni Antonella; Festa Felice; Tecco Simona

    2012-01-01

    Abstract Objective The purpose of this study was to determine the condylar volume in subjects with different mandibular divergence and skeletal class using cone-beam computed tomography (CBCT) and analysis software. Materials and methods For 94 patients (46 females and 48 males; mean age 24.3 ± 6.5 years), resultant rendering reconstructions of the left and right temporal mandibular joints (TMJs) were obtained. Subjects were then classified on the base of ANB angle the GoGn-SN angle in three ...

  18. Influence of Zinc on the Surface Tension, Density and Molar Volume of (Ag-Sneut +Zn Liquid Alloys

    Directory of Open Access Journals (Sweden)

    Gąsior W.

    2016-03-01

    Full Text Available The dilatometric and maximum bubble pressure methods were applied for the measurements of the density and surface tension of liquid (Ag-Sneut +Zn lead-free solders. The experiments were carried out in the temperature range from 515 to 1223 K for the alloys of the zinc concentration equaling 0.01, 0.02, 0.04, 0.05, 0.1 and 0.2 of the mole fraction. It was found that the temperature dependence of both the density and the surface tension could be thought as linear, so they were interpreted by straight line equations. The experimental data of the molar volume of the investigated alloys were described by the polynomial dependent on the composition and temperature.

  19. The MAGIC Meteoric Smoke Particle Sampler - Description and Results

    Science.gov (United States)

    Hedin, J.

    2013-12-01

    Between a few to several hundred tons of meteoric material enters the Earth's atmosphere each day, and much of this material ablates in the 70 -130 km region of the atmosphere. Already in the early 1960's it was suggested that meteoroid ablation products could recondense and form solid nanometer-scale smoke particles in the altitude range of the mesosphere and lower thermosphere (MLT). These so-called meteoric smoke particles (MSPs) are then subject to further coagulation, sedimentation, and transport by the mesospheric meridional circulation which in turn determines the latitudinal and seasonal variation of the MSP distribution. MSPs have been suggested to be important for a variety of atmospheric phenomena: 1. they are the most likely candidate for the nuclei of mesospheric ice particles (NLC and PMSE); 2. they provide surface area on which heterogeneous chemical reactions take place and may influence, for example, the water vapor distribution and Ox/HOx chemistry in the mesosphere; 3. they act as ultimate sink in mesospheric metal chemistry by scavenging various gas-phase products of meteoric ablation; 4. they can significantly influence the ionospheric D-region charge balance by scavenging free electrons and positive ions; and 5. they may be involved in the formation of NAT particles in polar stratospheric clouds and the destruction of ozone. Given the above points, it is obvious that there is a large scientific interest in the properties and global distribution of MSPs. Basic information about MSP properties is today available from optical occultation measurements (AIM/SOFIE) and, more indirectly, from in-situ measurements of the charged particle population. In order to understand the role of meteoric smoke particles in the mesosphere and their impact on that environment their presence must be certified and their physical characterization (number density, size distribution, shape, composition etc.) determined. A way to obtain maximum information about particle

  20. Mechanical Behavior of PBO Fiber Used for Lunar Soil Sampler

    Science.gov (United States)

    Gao, Xingwen; Tang, Dewei; Yue, Honghao; Qiao, Fei; Li, Yanwei

    2017-06-01

    The stability of the mechanical properties of the materials used for lunar soil sampler at different temperatures is one of the key factors to ensure the success of the lunar sampling task. In this paper, two kinds of poly(pphenylene-2,6-benzobisoxazole) (PBO) fiber fabric used for lunar soil sampler, flexible tube and wireline, are tested for mechanical properties. The results show that the mechanical properties of the PBO flexible tube and wireline raised 8.3% and 5.7% respectively in -194°C environment comparing with the room temperature of 25°C. When the temperature rises to 300°C, the deviation is -38.6% and -46.4% respectively.

  1. Boltzmann Samplers, P\\'olya Theory, and Cycle Pointing

    CERN Document Server

    Bodirsky, Manuel; Kang, Mihyun; Vigerske, Stefan

    2010-01-01

    We introduce a general method to count unlabeled combinatorial structures and to efficiently generate them at random. The approach is based on pointing unlabeled structures in an "unbiased" way that a structure of size n gives rise to n pointed structures. We extend Polya theory to the corresponding pointing operator, and present a random sampling framework based on both the principles of Boltzmann sampling and on P\\'olya operators. All previously known unlabeled construction principles for Boltzmann samplers are special cases of our new results. Our method is illustrated on several examples: in each case, we provide enumerative results and efficient random samplers. The approach applies to unlabeled families of plane and nonplane unrooted trees, and tree-like structures in general, but also to families of graphs (such as cacti graphs and outerplanar graphs) and families of planar maps.

  2. Assessment of field-related influences on polychlorinated biphenyl exposures and sorbent amendment using polychaete bioassays and passive sampler measurements

    Science.gov (United States)

    Janssen, E.M.; Oen, A.M.; Luoma, S.N.; Luthy, R.G.

    2011-01-01

    Field-related influences on polychlorinated biphenyl (PCB) exposure were evaluated by employing caged deposit-feeders, Neanthes arenaceodentata, along with polyoxymethylene (POM) samplers using parallel in situ and ex situ bioassays with homogenized untreated or activated carbon (AC) amended sediment. The AC amendment achieved a remedial efficiency in reducing bioaccumulation by 90% in the laboratory and by 44% in the field transplants. In situ measurements showed that PCB uptake by POM samplers was greater for POM placed in the surface sediment compared with the underlying AC amendment, suggesting that tidal exchange of surrounding material with similar PCB availability as untreated sediment was redeposited in the cages. Polychlorinated biphenyls bioaccumulation with caged polychaetes from untreated sediment was half as large under field conditions compared with laboratory conditions. A biodynamic model was used to confirm and quantify the different processes that could have influenced these results. Three factors appeared most influential in the bioassays: AC amendment significantly reduces bioavailability under laboratory and field conditions; sediment deposition within test cages in the field partially masks the remedial benefit of underlying AC-amended sediment; and deposit-feeders exhibit less PCB uptake from untreated sediment when feeding is reduced. Ex situ and in situ experiments inevitably show some differences that are associated with measurement methods and effects of the environment. Parallel ex situ and in situ bioassays, passive sampler measurements, and quantifying important processes with a model can tease apart these field influences. ?? 2010 SETAC.

  3. Modeling the transport of organic chemicals between polyethylene passive samplers and water in finite and infinite bath conditions.

    Science.gov (United States)

    Tcaciuc, A Patricia; Apell, Jennifer N; Gschwend, Philip M

    2015-12-01

    Understanding the transfer of chemicals between passive samplers and water is essential for their use as monitoring devices of organic contaminants in surface waters. By applying Fick's second law to diffusion through the polymer and an aqueous boundary layer, the authors derived a mathematical model for the uptake of chemicals into a passive sampler from water, in finite and infinite bath conditions. The finite bath model performed well when applied to laboratory observations of sorption into polyethylene (PE) sheets for various chemicals (polycyclic aromatic hydrocarbons, polychlorinated biphenyls [PCBs], and dichlorodiphenyltrichloroethane [DDT]) and at varying turbulence levels. The authors used the infinite bath model to infer fractional equilibration of PCB and DDT analytes in field-deployed PE, and the results were nearly identical to those obtained using the sampling rate model. However, further comparison of the model and the sampling rate model revealed that the exchange of chemicals was inconsistent with the sampling rate model for partially or fully membrane-controlled transfer, which would be expected in turbulent conditions or when targeting compounds with small polymer diffusivities and small partition coefficients (e.g., phenols, some pesticides, and others). The model can be applied to other polymers besides PE as well as other chemicals and in any transfer regime (membrane, mixed, or water boundary layer-controlled). Lastly, the authors illustrate practical applications of this model such as improving passive sampler design and understanding the kinetics of passive dosing experiments.

  4. Locating air samplers inside a room using qualitative airflow studies

    Energy Technology Data Exchange (ETDEWEB)

    Kravchik, T.; Levinson, S.; German, U. [Nuclear Research Center Negev, Beer-Sheva (Israel); Haim, M. [Ben-Gurion University of the Negev, Beer-Sheva (Israel)

    2000-05-01

    The concentration of airborne radioactive materials inside a room can vary widely from one location to another, sometimes by orders of magnitude even for locations that are reactively close. Inappropriately placed air samplers can give misleading results and, therefore, the location of air samplers is important. Proper placement of samplers is not always obvious and cannot be determined simply by observing the position of room air supply and exhaust vents. Airflow studies, such as the release of smoke aerosols, should be used. The significance of airflow pattern studies depends on the purpose of sampling-for estimating worker intakes, warning of abnormally high concentrations, defining airborne radioactive areas, testing for confinement of sealed radioactive materials, etc. Qualitative smoke tests were conducted inside rooms using a 'KUPO Inc.' smoke tube (D5050 fog machine). Smoke was released at elevation of 1-2 meters and its path was recorded on worksheet drawings of the room. The tests revealed three types of airflow patterns inside the rooms: a) flow path with a definite stable direction, b) flow path which changes direction arbitrarily as a result of airflow vortices, and c) static/stagnant air. In some cases the airflow path direction was different from the expected one. This emphasizes the significance of conducting airflow studies for location of air samplers and not only relying on intuition. An airflow patterns comparison study between the qualitative smoke tests and computer simulation using a commercial finite element CFD code, FIDAP 8.01, was also conducted. The measured and the computed paths of the airflow were mostly in good agreement. The computer simulation indicated additional details which could not be observed when performing the smoke tests because of physical and visibility limitations. (author)

  5. Selective bibliography of surface coal mining and reclamation literature. Volume 2. Interior Coal Province

    Energy Technology Data Exchange (ETDEWEB)

    Patricoski, M. L.; Daniels, L. K.; Sobek, A. A.

    1979-08-01

    This bibliography has been compiled for use by researchers, students, and other groups who need a reference source of published literature related to surface coal mining and reclamation in the Interior Coal Province. This bibliography contains more than 1300 references, including government reports, journal articles, symposium proceedings, industrial reports, workshop proceedings, theses, and bibliographies. A simple format was used to categorize citations.

  6. County-Level Climate Uncertainty for Risk Assessments: Volume 15 Appendix N - Forecast Surface Runoff.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lowry, Thomas Stephen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Shannon M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Walker, La Tonya Nicole [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Barry L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Malczynski, Leonard A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  7. County-Level Climate Uncertainty for Risk Assessments: Volume 14 Appendix M - Historical Surface Runoff.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  8. Constraints on geothermal reservoir volume change calculations from InSAR surface displacements and injection and production data

    Science.gov (United States)

    Kaven, J. Ole; Barbour, Andrew J.; Ali, Tabrez

    2017-04-01

    Continual production of geothermal energy at times leads to significant surface displacement that can be observed in high spatial resolution using InSAR imagery. The surface displacement can be analyzed to resolve volume change within the reservoir revealing the often-complicated patterns of reservoir deformation. Simple point source models of reservoir deformation in a homogeneous elastic or poro-elastic medium can be superimposed to provide spatially varying, kinematic representations of reservoir deformation. In many cases, injection and production data are known in insufficient detail; but, when these are available, the same Green functions can be used to constrain the reservoir deformation. Here we outline how the injection and production data can be used to constrain bounds on the solution by posing the inversion as a quadratic programming with inequality constraints and regularization rather than a conventional least squares solution with regularization. We apply this method to InSAR-derived surface displacements at the Coso and Salton Sea Geothermal Fields in California, using publically available injection and production data. At both geothermal fields the available surface deformation in conjunction with the injection and production data permit robust solutions for the spatially varying reservoir deformation. The reservoir deformation pattern resulting from the constrained quadratic programming solution is more heterogeneous when compared to a conventional least squares solution. The increased heterogeneity is consistent with the known structural controls on heat and fluid transport in each geothermal reservoir.

  9. 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.

  10. Asynchronous signal-dependent non-uniform sampler

    Science.gov (United States)

    Can-Cimino, Azime; Chaparro, Luis F.; Sejdić, Ervin

    2014-05-01

    Analog sparse signals resulting from biomedical and sensing network applications are typically non-stationary with frequency-varying spectra. By ignoring that the maximum frequency of their spectra is changing, uniform sampling of sparse signals collects unnecessary samples in quiescent segments of the signal. A more appropriate sampling approach would be signal-dependent. Moreover, in many of these applications power consumption and analog processing are issues of great importance that need to be considered. In this paper we present a signal dependent non-uniform sampler that uses a Modified Asynchronous Sigma Delta Modulator which consumes low-power and can be processed using analog procedures. Using Prolate Spheroidal Wave Functions (PSWF) interpolation of the original signal is performed, thus giving an asynchronous analog to digital and digital to analog conversion. Stable solutions are obtained by using modulated PSWFs functions. The advantage of the adapted asynchronous sampler is that range of frequencies of the sparse signal is taken into account avoiding aliasing. Moreover, it requires saving only the zero-crossing times of the non-uniform samples, or their differences, and the reconstruction can be done using their quantized values and a PSWF-based interpolation. The range of frequencies analyzed can be changed and the sampler can be implemented as a bank of filters for unknown range of frequencies. The performance of the proposed algorithm is illustrated with an electroencephalogram (EEG) signal.

  11. Modeling uptake of hydrophobic organic contaminants into polyethylene passive samplers.

    Science.gov (United States)

    Thompson, Jay M; Hsieh, Ching-Hong; Luthy, Richard G

    2015-02-17

    Single-phase passive samplers are gaining acceptance as a method to measure hydrophobic organic contaminant (HOC) concentration in water. Although the relationship between the HOC concentration in water and passive sampler is linear at equilibrium, mass transfer models are needed for nonequilibrium conditions. We report measurements of organochlorine pesticide diffusion and partition coefficients with respect to polyethylene (PE), and present a Fickian approach to modeling HOC uptake by PE in aqueous systems. The model is an analytic solution to Fick's second law applied through an aqueous diffusive boundary layer and a polyethylene layer. Comparisons of the model with existing methods indicate agreement at appropriate boundary conditions. Laboratory release experiments on the organochlorine pesticides DDT, DDE, DDD, and chlordane in well-mixed slurries support the model's applicability to aqueous systems. In general, the advantage of the model is its application in the cases of well-agitated systems, low values of polyethylene-water partioning coefficients, thick polyethylene relative to the boundary layer thickness, and/or short exposure times. Another significant advantage is the ability to estimate, or at least bound, the needed exposure time to reach a desired CPE without empirical model inputs. A further finding of this work is that polyethylene diffusivity does not vary by transport direction through the sampler thickness.

  12. 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 PM2.5 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 PM2.5 across a broad range of concentrations. © 2016 The Authors. Indoor Air published by John Wiley & Sons Ltd.

  13. 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

  14. Civilian American and European Surface Anthropometry Resource (CAESAR). Volume 2: Descriptions

    Science.gov (United States)

    2002-06-01

    epicondyle landmark. Method: Calculated point-to-surface distance. Instrument: Whole-body scanner 91. CAESAR Name: ELBOW HEIGHT, SITTING (COMFORTABLE...Epicn Elbow Ht Sit Rt Zdelta Rt. Humeral Lateral Epicn Rt. Trochanterion; and Functional Butt Block Rt. Femoral Lateral Epicn Femoral Epicondyle Lat to...CAESAR Name: OLECRANON, RIGHT ISO Definition No. N/A Description: Posterior point on the olecranon process of the ulna, marked with the elbow bent 90

  15. A lifting surface computer code with jet-in-crossflow interference effects. Volume 1: Theoretical description

    Science.gov (United States)

    Furlong, K. L.; Fearn, R. L.

    1983-01-01

    A method is proposed to combine a numerical description of a jet in a crossflow with a lifting surface panel code to calculate the jet/aerodynamic-surface interference effects on a V/STOL aircraft. An iterative technique is suggested that starts with a model for the properties of a jet/flat plate configuration and modifies these properties based on the flow field calculated for the configuration of interest. The method would estimate the pressures, forces, and moments on an aircraft out of ground effect. A first-order approximation to the method suggested is developed and applied to two simple configurations. The first-order approximation is a noniterative precedure which does not allow for interactions between multiple jets in a crossflow and also does not account for the influence of lifting surfaces on the jet properties. The jet/flat plate model utilized in the examples presented is restricted to a uniform round jet injected perpendicularly into a uniform crossflow for a range of jet-to-crossflow velocity ratios from three to ten.

  16. Polymer-water partition coefficients in polymeric passive samplers.

    Science.gov (United States)

    Asgarpour Khansary, Milad; Shirazian, Saeed; Asadollahzadeh, Mehdi

    2017-01-01

    Passive samplers are of the most applied methods and tools for measuring concentration of hydrophobic organic compounds in water (c 1(W) ) in which the polymer-water partition coefficients (D) are of fundamental importance for reliability of measurements. Due to the cost and time associated with the experimental researches, development of a predictive method for estimation and evaluation of performance of polymeric passive samplers for various hydrophobic organic compounds is highly needed and valuable. For this purpose, in this work, following the fundamental chemical thermodynamic equations governing the concerned local equilibrium, successful attempts were made to establish a theoretical model of polymer-water partition coefficients. Flory-Huggins model based on the Hansen solubility parameters was used for calculation of activity coefficients. The method was examined for reliability of calculations using collected data of three polymeric passive samplers and ten compounds. A regression model of form ln(D) = 0.707ln(c 1(p) ) - 2.7391 with an R (2)  = 0.9744 was obtained to relate the polymer-water partition coefficients (D) and concentration of hydrophobic organic compounds in passive sampler (c 1(p) ). It was also found that polymer-water partition coefficients are related to the concentration of hydrophobic organic compounds in water (c 1(W) ) as ln(D) = 2.412ln(c 1(p) ) - 9.348. Based on the results, the tie lines of concentration for hydrophobic organic compounds in passive sampler (c 1(p) ) and concentration of hydrophobic organic compounds in water (c 1(W) ) are in the form of ln(c 1(W) ) = 0.293ln(c 1(p) ) + 2.734. The composition of water sample and the interaction parameters of dissolved compound-water and dissolved compound-polymer, temperature, etc. actively influence the values of partition coefficient. The discrepancy observed over experimental data can be simply justified based on the local condition of sampling sites which alter

  17. Comparison of grey matter volume and thickness for analysing cortical changes in chronic schizophrenia: a matter of surface area, grey/white matter intensity contrast, and curvature.

    Science.gov (United States)

    Kong, Li; Herold, Christina J; Zöllner, Frank; Salat, David H; Lässer, Marc M; Schmid, Lena A; Fellhauer, Iven; Thomann, Philipp A; Essig, Marco; Schad, Lothar R; Erickson, Kirk I; Schröder, Johannes

    2015-02-28

    Grey matter volume and cortical thickness are the two most widely used measures for detecting grey matter morphometric changes in various diseases such as schizophrenia. However, these two measures only share partial overlapping regions in identifying morphometric changes. Few studies have investigated the contributions of the potential factors to the differences of grey matter volume and cortical thickness. To investigate this question, 3T magnetic resonance images from 22 patients with schizophrenia and 20 well-matched healthy controls were chosen for analyses. Grey matter volume and cortical thickness were measured by VBM and Freesurfer. Grey matter volume results were then rendered onto the surface template of Freesurfer to compare the differences from cortical thickness in anatomical locations. Discrepancy regions of the grey matter volume and thickness where grey matter volume significantly decreased but without corresponding evidence of cortical thinning involved the rostral middle frontal, precentral, lateral occipital and superior frontal gyri. Subsequent region-of-interest analysis demonstrated that changes in surface area, grey/white matter intensity contrast and curvature accounted for the discrepancies. Our results suggest that the differences between grey matter volume and thickness could be jointly driven by surface area, grey/white matter intensity contrast and curvature.

  18. The effect of drop volume and micropillar shape on the apparent contact angle of ordered microstructured surfaces.

    Science.gov (United States)

    Afferrante, Luciano; Carbone, Giuseppe

    2014-06-14

    In the present paper, we propose a new theoretical approach to evaluate the shape and apparent contact angle (ACA) of a drop gently deposited on microstructured superhydrophobic surfaces. We exploit the very large separation of scales between the drop size and the features of the micromorphology of the interface to propose a numerical methodology to calculate the apparent contact area and apparent contact angle. In agreement with very recent experiments, calculations show that, in the case of surfaces made of conical micropillars, the ACA may take values very close to 180° not depending on the size of the liquid drop. At large drop volumes, the shape of the drop deviates from the spherical one as a result of the gravity effects, but it is noteworthy that the apparent contact angle does not change at all. Our calculations shows that this holds true also for different pillar shapes, showing that, for any given Young contact angle of the solid constituting the pillars, the ACA is an intrinsic property of the surface microgeometry.

  19. Use of portable microbial samplers for estimating inhalation exposure to viable biological agents.

    Science.gov (United States)

    Yao, Maosheng; Mainelis, Gediminas

    2007-01-01

    Portable microbial samplers are being increasingly used to determine the presence of microbial agents in the air; however, their performance characteristics when sampling airborne biological agents are largely unknown. In addition, it is unknown whether these samplers could be used to assess microbial inhalation exposure according to the particle sampling conventions. This research analyzed collection efficiencies of MAS-100, Microflow, SMA MicroPortable, Millipore Air Tester, SAS Super 180, BioCulture, and RCS High Flow portable microbial samplers when sampling six bacterial and fungal species ranging from 0.61 to 3.14 microm in aerodynamic diameter. The efficiencies with which airborne microorganisms were deposited on samplers' collection medium were compared to the particle inhalation and lung deposition convention curves. When sampling fungi, RCS High Flow and SAS Super 180 deposited 80%-90% of airborne spores on agar - highest among investigated samplers. Other samplers showed collection efficiencies of 10%-60%. When collecting bacteria, RCS High Flow and MAS-100 collected 20%-30%, whereas other samplers collected less than 10% of these bioparticles. Comparison of samplers' collection efficiencies with particle inhalation convention curves showed that RCS High Flow and SAS Super 180 could be used to assess inhalation exposure to particles larger than 2.5 microm, such as fungal spores. Performance of RCS High Flow sampler was also reflective of the particle lung deposition pattern when sampling both bacteria and fungi. MAS-100 and SAS Super 180 matched the total deposition curve fairly well when collecting bacterial and fungi species, respectively. For other tested samplers, we observed substantial discrepancies between their performances and particle deposition efficiencies in the lung. The results show that feasibility of applying portable microbial samplers for exposure assessment depends on a particular sampler model and microbial species.

  20. Unconventional oil and gas spills: Materials, volumes, and risks to surface waters in four states of the U.S.

    Science.gov (United States)

    Maloney, Kelly O.; Baruch-Mordo, Sharon; Patterson, Lauren A.; Nicot, Jean-Philippe; Entrekin, Sally; Fargione, Joe E.; Kiesecker, Joseph M.; Konschnik, Kate E.; Ryan, Joseph N.; Trainor, Anne M.; Saiers, James E.; Wiseman, Hannah J.

    2017-01-01

    Extraction of oil and gas from unconventional sources, such as shale, has dramatically increased over the past ten years, raising the potential for spills or releases of chemicals, waste materials, and oil and gas. We analyzed spill data associated with unconventional wells from Colorado, New Mexico, North Dakota and Pennsylvania from 2005 to 2014, where we defined unconventional wells as horizontally drilled into an unconventional formation. We identified materials spilled by state and for each material we summarized frequency, volumes and spill rates. We evaluated the environmental risk of spills by calculating distance to the nearest stream and compared these distances to existing setback regulations. Finally, we summarized relative importance to drinking water in watersheds where spills occurred. Across all four states, we identified 21,300 unconventional wells and 6622 reported spills. The number of horizontal well bores increased sharply beginning in the late 2000s; spill rates also increased for all states except PA where the rate initially increased, reached a maximum in 2009 and then decreased. Wastewater, crude oil, drilling waste, and hydraulic fracturing fluid were the materials most often spilled; spilled volumes of these materials largely ranged from 100 to 10,000 L. Across all states, the average distance of spills to a stream was highest in New Mexico (1379 m), followed by Colorado (747 m), North Dakota (598 m) and then Pennsylvania (268 m), and 7.0, 13.3, and 20.4% of spills occurred within existing surface water setback regulations of 30.5, 61.0, and 91.4 m, respectively. Pennsylvania spills occurred in watersheds with a higher relative importance to drinking water than the other three states. Results from this study can inform risk assessments by providing improved input parameters on volume and rates of materials spilled, and guide regulations and the management policy of spills.

  1. Sex determination using discriminant analysis of upper and lower extremity bones: New approach using the volume and surface area of digital model.

    Science.gov (United States)

    Lee, U-Young; Kim, In-Beom; Kwak, Dai-Soon

    2015-08-01

    This study used 110 CT images taken from donated Korean cadavers to create 3-D models of the following upper and lower limb bones: the clavicle, scapula, humerus, radius, ulna, hip bone (os coxa), femur, patella (knee cap), tibia, talus, and calcaneus. In addition, the bone volume and surface area were calculated to determine sex differences using discriminant analysis. Significant sex differences were found in all bones with respect to volume and surface area (phip bone>tibia>humerus>scapula), although the order of surface area was different. The largest surface area in men was the femur and in women was the hip bone (psex determination (94%). When using the surface area of multiple bones, the maximum accuracy (99.4%) was achieved. The equation was as follows: (discriminant equation of surface area; femalesex determination.

  2. A surface acoustic wave-driven micropump for particle uptake investigation under physiological flow conditions in very small volumes

    Directory of Open Access Journals (Sweden)

    Florian G. Strobl

    2015-02-01

    Full Text Available Static conditions represent an important shortcoming of many in vitro experiments on the cellular uptake of nanoparticles. Here, we present a versatile microfluidic device based on acoustic streaming induced by surface acoustic waves (SAWs. The device offers a convenient method for introducing fluid motion in standard cell culture chambers and for mimicking capillary blood flow. We show that shear rates over the whole physiological range in sample volumes as small as 200 μL can be achieved. A precise characterization method for the induced flow profile is presented and the influence of flow on the uptake of Pt-decorated CeO2 particles by endothelial cells (HMEC-1 is demonstrated. Under physiological flow conditions the particle uptake rates for this system are significantly lower than at low shear conditions. This underlines the vital importance of the fluidic environment for cellular uptake mechanisms.

  3. A QR accelerated volume-to-surface boundary condition for finite element solution of eddy current problems

    Energy Technology Data Exchange (ETDEWEB)

    White, D; Fasenfest, B; Rieben, R; Stowell, M

    2006-09-08

    We are concerned with the solution of time-dependent electromagnetic eddy current problems using a finite element formulation on three-dimensional unstructured meshes. We allow for multiple conducting regions, and our goal is to develop an efficient computational method that does not require a computational mesh of the air/vacuum regions. This requires a sophisticated global boundary condition specifying the total fields on the conductor boundaries. We propose a Biot-Savart law based volume-to-surface boundary condition to meet this requirement. This Biot-Savart approach is demonstrated to be very accurate. In addition, this approach can be accelerated via a low-rank QR approximation of the discretized Biot-Savart law.

  4. User's manual for MODCAL: Bounding surface soil plasticity model calibration and prediction code, volume 2

    Science.gov (United States)

    Dennatale, J. S.; Herrmann, L. R.; Defalias, Y. F.

    1983-02-01

    In order to reduce the complexity of the model calibration process, a computer-aided automated procedure has been developed and tested. The computer code employs a Quasi-Newton optimization strategy to locate that set of parameter values which minimizes the discrepancy between the model predictions and the experimental observations included in the calibration data base. Through application to a number of real soils, the automated procedure has been found to be an efficient, reliable and economical means of accomplishing model calibration. Although the code was developed specifically for use with the Bounding Surface plasticity model, it can readily be adapted to other constitutive formulations. Since the code greatly reduces the dependence of calibration success on user expertise, it significantly increases the accessibility and usefulness of sophisticated material models to the general engineering community.

  5. Oil shale mining cost analysis. Volume I. Surface retorting process. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Resnick, B.S.; English, L.M.; Metz, R.D.; Lewis, A.G.

    1981-01-01

    An Oil Shale Mining Economic Model (OSMEM) was developed and executed for mining scenarios representative of commercially feasible mining operations. Mining systems were evaluated for candidate sites in the Piceance Creek Basin. Mining methods selected included: (1) room-and-pillar; (2) chamber-and-pillar, with spent shale backfilling; (3) sublevel stopping; and (4) sublevel stopping, with spent shale backfilling. Mines were designed to extract oil shale resources to support a 50,000 barrels-per-day surface processing facility. Costs developed for each mining scenario included all capital and operating expenses associated with the underground mining methods. Parametric and sensitivity analyses were performed to determine the sensitivity of mining cost to changes in capital cost, operating cost, return on investment, and cost escalation.

  6. UO{sub 2} corrosion in high surface-area-to-volume batch experiments.

    Energy Technology Data Exchange (ETDEWEB)

    Bates, J. K.; Finch, R. J.; Hanchar, J. M.; Wolf, S. F.

    1997-12-08

    Unsaturated drip tests have been used to investigate the alteration of unirradiated UO{sub 2} and spent UO{sub 2} fuel in an unsaturated environment such as may be expected in the proposed repository at Yucca Mountain. In these tests, simulated groundwater is periodically injected onto a sample at 90 C in a steel vessel. The solids react with the dripping groundwater and water condensed on surfaces to form a suite of U(VI) alteration phases. Solution chemistry is determined from leachate at the bottom of each vessel after the leachate stops interacting with the solids. A more detailed knowledge of the compositional evolution of the leachate is desirable. By providing just enough water to maintain a thin film of water on a small quantity of fuel in batch experiments, we can more closely monitor the compositional changes to the water as it reacts to form alteration phases.

  7. UO2 CORROSION IN HIGH SURFACE-AREA-TO-VOLUME BATCH EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Finch, Robert J.; Wolf, Stephen F.; Hanchar, John M.; Bates, John K.

    1998-05-11

    Unsaturated drip tests have been used to investigate the alteration of unirradiated UO{sub 2} and spent UO{sub 2} fuel in an unsaturated environment, such as may be expected in the proposed repository at Yucca Mountain. In these tests, simulated groundwater is periodically injected onto a sample at 90 C in a steel vessel. The solids react with the dripping groundwater and water condensed on surfaces to form a suite of U(VI) alteration phases. Solution chemistry is determined from leachate at the bottom of each vessel after the leachate stops interacting with the solids. A more detailed knowledge of the compositional evolution of the leachate is desirable. By providing just enough water to maintain a thin film of water on a small quantity of fuel in batch experiments, we can more closely monitor the compositional changes to the water as it reacts to form alteration phases.

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

    CSIR Research Space (South Africa)

    Pretorius, CJ

    2011-10-01

    Full Text Available of respirable samplers specify a specific flow rate so that the cut-point (or D50) for the sampler is ? 4 ?m. The convention is to report the particle size distribution (PSD) of dust as the D50 in ?m where 50% of the particles have a parti- cle size below... of a material dust to compute the PSD. After the laboratory and fieldwork sampling was completed, only the X- and Y-Samplers were cut open so that the samplers could be investigated on the inside. 4 RESULTS AND DISCUSSION 4.1 Results...

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

    Science.gov (United States)

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

    2012-05-01

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

  10. Development of an improved methodology to detect infectious airborne influenza virus using the NIOSH bioaerosol sampler.

    Science.gov (United States)

    Cao, G; Noti, J D; Blachere, F M; Lindsley, W G; Beezhold, D H

    2011-12-01

    A unique two-stage cyclone bioaerosol sampler has been developed at NIOSH that can separate aerosols into three size fractions. The ability of this sampler to collect infectious airborne viruses from a calm-air chamber loaded with influenza A virus was tested. The sampler's efficiency at collecting aerosolized viral particles from a calm-air chamber is essentially the same as that from the high performance SKC BioSampler that collects un-fractionated particles directly into a liquid media (2.4 × 10(4) total viral particles per liter of sampled air (TVP/L) versus 2.6 × 10(4) TVP/L, respectively, after 15 min) and the efficiency is relatively constant over collection times of 15, 30 and 60 min. Approximately 34% of the aerosolized infectious virus collected after 15 min with the NIOSH bioaerosol sampler remained infectious, and infectious virus was found in all three size fractions. After 60 min of sampling, the infectious virus/liter air found in the NIOSH bioaerosol sampler was 15% of that found in the SKC BioSampler. This preservation of infectivity by the NIOSH bioaerosol sampler was maintained even when the initial infectivity prior to aerosolization was as low as 0.06%. The utility of the NIOSH bioaerosol sampler was further extended by incorporating an enhanced infectivity detection methodology developed in our laboratory, the viral replication assay, which amplified the infectious virus making it more readily detectable.

  11. Efficacy of a vacuum benthos sampler for collecting demersal fish eggs from gravel substratum

    Science.gov (United States)

    Ruetz, C. R.; Jennings, C.A.

    1997-01-01

    We used two densities of eggs (low=900 eggs/m2; high=5100 eggs/m2) in laboratory experiments to estimate the recovery efficiency of the Brown benthos sampler for collecting fish eggs from gravel substrate and to determine if differences (e.g., 5-fold) in egg density in the substratum could be detected with the sampler. The mean egg recovery efficiency of the sampler in the low and high density treatments was 30% (SE=8.7) and 35% (SE=3.8), respectively. The difference between the treatment means was not significant. Therefore, data from the two treatments were pooled and used to estimate the recovery efficiency of the sampler (32.7%, SE=4.4). However, we were able to detect a 5?? difference in the number of eggs collected with the sampler between the two treatments. Our estimate of the recovery efficiency of the sampler for collecting fish eggs was less than those reported for the sampler's efficiency for collecting benthic macroinvertebrates. The low recovery efficiency of the sampler for collecting fish eggs does not lessen the utility of the device. Rather, ecologists planning to use the sampler must estimate the recovery efficiency of target fauna, especially if density estimates are to be calculated, because recovery efficiency probably is less than 100%. ?? Munksgaard, 1997.

  12. A sample-freezing drive shoe for a wire line piston core sampler

    Science.gov (United States)

    Murphy, F.; Herkelrath, W.N.

    1996-01-01

    Loss of fluids and samples during retrieval of cores of saturated, noncohesive sediments results in incorrect measures of fluid distributions and an inaccurate measure of the stratigraphic position of the sample. To reduce these errors, we developed a hollow drive shoe that freezes in place the lowest 3 inches (75 mm) of a 1.88-inch-diameter (48 mm), 5-foot-long (1.5 m) sediment sample taken using a commercial wire line piston core sampler. The end of the core is frozen by piping liquid carbon dioxide at ambient temperature through a steel tube from a bottle at the land surface to the drive shoe where it evaporates and expands, cooling the interior surface of the shoe to about -109??F (-78??C). Freezing a core end takes about 10 minutes. The device was used to collect samples for a study of oil-water-air distributions, and for studies of water chemistry and microbial activity in unconsolidated sediments at the site of an oil spill near Bemidji, Minnesota. Before freezing was employed, samples of sandy sediments from near the water table sometimes flowed out of the core barrel as the sampler was withdrawn. Freezing the bottom of the core allowed for the retention of all material that entered the core barrel and lessened the redistribution of fluids within the core. The device is useful in the unsaturated and shallow saturated zones, but does not freeze cores well at depths greater than about 20 feet (6 m) below water, possibly because the feed tube plugs with dry ice with increased exhaust back-pressure, or because sediment enters the annulus between the core barrel and the core barrel liner and blocks the exhaust.

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

    Science.gov (United States)

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

    2011-04-01

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

  14. The role of mass balance equations in growth mechanics illustrated in surface and volume dissolutions.

    Science.gov (United States)

    Ateshian, Gerard A

    2011-01-01

    Growth mechanics problems require the solution of mass balance equations that include supply terms and account for mass exchanges among constituents of a mixture. Though growth may often be accompanied by a variety of concomitant phenomena that increase modeling complexity, such as solid matrix deformation, evolving traction-free configurations, cell division, and active cell contraction, it is important to distinguish these accompanying phenomena from the fundamental growth process that consists of deposition or removal of mass from the solid matrix. Therefore, the objective of this study is to present a canonical problem of growth, namely, dissolution of a rigid solid matrix in a solvent. This problem illustrates a case of negative growth (loss of mass) of the solid in a mixture framework that includes three species, a solid, a solvent, and a solute, where the solute is the product of the solid dissolution. By analyzing both volumetric and surface dissolutions, the two fundamental modes of growth are investigated within the unified framework of mixture theory.

  15. Analysis of the structural parameters that influence gas production from the Devonian shale. Annual progress report, 1979-1980. Volume II. Data repository and reports published during fiscal year 1979-1980: regional structure, surface structure, surface fractures, hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Negus-De Wys, J.; Dixon, J. M.; Evans, M. A.; Lee, K. D.; Ruotsala, J. E.; Wilson, T. H.; Williams, R. T.

    1980-10-01

    This volume comprises appendices giving regional structure data, surface structure data, surface fracture data, and hydrology data. The fracture data covers oriented Devonian shale cores from West Virginia, Ohio, Virginia, Pennsylvania, and Kentucky. The subsurface structure of the Eastern Kentucky gas field is also covered. (DLC)

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

    Science.gov (United States)

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

    2011-12-01

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

  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. Is the Maxillary Sinus Really Suitable in Sex Determination? A Three-Dimensional Analysis of Maxillary Sinus Volume and Surface Depending on Sex and Dentition.

    Science.gov (United States)

    Möhlhenrich, Stephan Christian; Heussen, Nicole; Peters, Florian; Steiner, Timm; Hölzle, Frank; Modabber, Ali

    2015-11-01

    The morphometric analysis of maxillary sinus was recently presented as a helpful instrument for sex determination. The aim of the present study was to examine the volume and surface of the fully dentate, partial, and complete edentulous maxillary sinus depending on the sex. Computed tomography data from 276 patients were imported in DICOM format via special virtual planning software, and surfaces (mm) and volumes (mm) of maxillary sinuses were measured. In sex-specific comparisons (women vs men), statistically significant differences for the mean maxillary sinus volume and surface were found between fully dentate (volume, 13,267.77 mm vs 16,623.17 mm, P sexes, no differences were only measured for female and male partially dentate fully edentulous sinuses (2 teeth missing) and between partially edentulous sinuses in women and men (1 teeth vs 2 teeth missing). With a corresponding software program, it is possible to analyze the maxillary sinus precisely. The dentition influences the volume and surface of the pneumatic maxillary sinus. Therefore, sex determination is possible by analysis of the maxillary sinus event through the increase in pneumatization.

  19. Improved characterization of gas-particle partitioning for per- and polyfluoroalkyl substances in the atmosphere using annular diffusion denuder samplers.

    Science.gov (United States)

    Ahrens, Lutz; Harner, Tom; Shoeib, Mahiba; Lane, Douglas A; Murphy, Jennifer G

    2012-07-03

    Gas-phase perfluoroalkyl carboxylic acids (PFCAs) sorb strongly on filter material (i.e., GFF, QFF) used in conventional high volume air samplers, which results in an overestimation of the particle-phase concentration. In this study, we investigated an improved technique for measuring the gas-particle partitioning of per- and polyfluoroalkyl substances (PFASs) using an annular diffusion denuder sampler. Samples were analyzed for 7 PFAS classes [i.e., PFCAs, perfluoroalkane sulfonic acids (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer methacrylates (FTMACs), fluorotelomer acrylates (FTACs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamidoethanols (FOSEs)]. The measured particulate associated fraction (Φ') using the diffusion denuder sampler generally followed the trend FTACs (0%) < FTOHs (~8%) < FOSAs (~21%) < PFSAs (~29%) < FOSEs (~66%), whereas the Φ' of the C(8)-C(18) PFCAs increased with carbon chain length, and ranged from 6% to 100%. The ionizability of some PFASs, when associated with particles, is an important consideration when calculating the gas-particle partitioning coefficient as both ionic and neutral forms can be present in the particles. Here we differentiate between a gas-particle partitioning coefficient for neutral species, K(p), and one that accounts for both ionic and neutral species of a compound, K(p)'. The measured K(p)' for PFSAs and PFCAs was 4-5 log units higher compared to the interpolated K(p) for the neutral form only. The measured K(p)' can be corrected (to apply to the neutral form only) with knowledge of the pK(a) of the chemical and the pH of the condensed medium ("wet" particle or aqueous aerosol). The denuder-based sampling of PFASs has yielded a robust data set that demonstrates the importance of atmospheric pH and chemical pK(a) values in determining gas-particle partitioning of PFASs.

  20. Use of depuration compounds in passive air samplers: results from active sampling-supported field deployment, potential uses, and recommendations.

    Science.gov (United States)

    Moeckel, Claudia; Harner, Tom; Nizzetto, Luca; Strandberg, Bo; Lindroth, Anders; Jones, Kevin C

    2009-05-01

    Depuration compounds (DCs) are added to passive air samplers (PAS) prior to deployment to account for the wind-dependency of the sampling rate for gas-phase compounds. This correction is particularly useful for providing comparable data for samplers that are deployed in different environments and subject to different meteorological conditions such as wind speeds. Two types of PAS--the polyurethane foam (PUF) disk sampler and semipermeable membrane devices (SPMDs)--were deployed at eight heights on a 100 m tower to test whether the DC approach could yield air concentrations profiles for PCBs and organochlorine pesticides and account for the wind speed gradient with height. Average wind speeds ranged from 0.3 to 4.5 m s(-1) over the 40 day deployment, increasing with height Two low volume active air samples (AAS), one collected at 25 m and one at 73 m over the 40 day deployment showed no significant concentration differences for target compounds. As expected, the target compounds taken up by PAS reflected the wind profile with height This wind-dependency of the PAS was also reflected in the results of the DCs. A correction based on the DC approach successfully accounted for the effect of wind on PAS sampling rates, yielding a profile consistent with the AAS. Interestingly, in terms of absolute air concentrations, there were differences between the AAS and PAS-derived values for some target compounds. These were attributed to different sampling characteristics of the two approaches that may have resulted in slightly different air masses being sampled. Based on the results of this study, guidelines are presented for the use of DCs and for the calibration of PAS using AAS.

  1. A field experiment with variable-suction multi-compartment samplers to measure the spatio-temporal distribution of solute leaching in an agricultural soil

    Science.gov (United States)

    Bloem, E.; Hogervorst, F. A. N.; de Rooij, G. H.

    2009-04-01

    Solutes spread out in time and space as they move downwards from the soil surface with infiltrating water. Solute monitoring in the field is often limited to observations of resident concentrations, while flux concentrations govern the movement of solutes in soils. A recently developed multi-compartment sampler is capable of measuring fluxes at a high spatial resolution with minimal disturbance of the local pressure head field. The objective of this paper is to use this sampler to quantify the spatial and temporal variation of solute leaching below the root zone in an agricultural field under natural rainfall in winter and spring. We placed two samplers at 31 and 25 cm depth in an agricultural field, leaving the soil above undisturbed. Each sampler contained 100 separate cells of 31 × 31 mm. Water fluxes were measured every 5 min for each cell. We monitored leaching of a chloride pulse under natural rainfall by frequently extracting the collected leachate while leaving the samplers buried in situ. This experiment was followed by a dye tracer experiment. This setting yielded information that widely surpassed the information that can be provided by separate anionic and dye tracer trials, and solute transport monitoring by coring or suction cups. The detailed information provided by the samplers showed that percolation at the sampling depth started much faster (approximately 3 h after the start of rainfall) in initially wet soil (pressure head above - 65 cm) than in drier soil (more than 14 h at pressure heads below - 80 cm). At any time, 25% of the drainage passed through 5-6% of the sampled area, reflecting the effect of heterogeneity on the flow paths. The amount of solute carried by individual cells varied over four orders of magnitude. The lateral concentration differences were limited though. This suggests a convective-dispersive regime despite the short vertical travel distance. On the other hand, the dilution index indicates a slight tendency towards

  2. A fast 3D surface reconstruction and volume estimation method for grain storage based on priori model

    Science.gov (United States)

    Liang, Xian-hua; Sun, Wei-dong

    2011-06-01

    Inventory checking is one of the most significant parts for grain reserves, and plays a very important role on the macro-control of food and food security. Simple, fast and accurate method to obtain internal structure information and further to estimate the volume of the grain storage is needed. Here in our developed system, a special designed multi-site laser scanning system is used to acquire the range data clouds of the internal structure of the grain storage. However, due to the seriously uneven distribution of the range data, this data should firstly be preprocessed by an adaptive re-sampling method to reduce the data redundancy as well as noise. Then the range data is segmented and useful features, such as plane and cylinder information, are extracted. With these features a coarse registration between all of these single-site range data is done, and then an Iterative Closest Point (ICP) algorithm is carried out to achieve fine registration. Taking advantage of the structure of the grain storage being well defined and the types of them are limited, a fast automatic registration method based on the priori model is proposed to register the multi-sites range data more efficiently. Then after the integration of the multi-sites range data, the grain surface is finally reconstructed by a delaunay based algorithm and the grain volume is estimated by a numerical integration method. This proposed new method has been applied to two common types of grain storage, and experimental results shown this method is more effective and accurate, and it can also avoids the cumulative effect of errors when registering the overlapped area pair-wisely.

  3. 50 CFR 697.12 - At-sea sea sampler/observer coverage.

    Science.gov (United States)

    2010-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) ATLANTIC COASTAL FISHERIES COOPERATIVE... must: (1) Notify the sea sampler/observer of any sea turtles, marine mammals, or other specimens taken by the vessel. (2) Provide the sea sampler/observer with sea turtles, marine mammals, or...

  4. Analysis of Convergence Rates of Some Gibbs Samplers on Continuous State Spaces

    CERN Document Server

    Smith, Aaron

    2011-01-01

    We use a non-Markovian coupling and small modi?cations of techniques from the theory of ?nite Markov chains to analyze some Markov chains on continuous state spaces. The ?rst is a Gibbs sampler on narrow contingency tables, the second a gen- eralization of a sampler introduced by Randall and Winkler.

  5. Comparison of continuous monitor (TEOM) and gravimetric sampler particulate matter concentrations

    Science.gov (United States)

    The Tapered Element Oscillating Microbalance (TEOM) sampler is an EPA designated equivalent method sampler for measuring PM10 concentrations. PM10 refers to the mass fraction of particulate matter suspended in the atmosphere having a nominal aerodynamic diameter less than or equal to 10 micrometers ...

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

    Energy Technology Data Exchange (ETDEWEB)

    BOGER, R.M.

    1999-11-18

    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.

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

    CSIR Research Space (South Africa)

    Pretorius, CJ

    2011-07-01

    Full Text Available manufactured size- selective samplers (Pretorius 2010) found that the samplers (i.e. cyclones) remove not only the respira- ble fraction of the dust from the airborne dust but al- so particles of much larger than ten micron. The im- plication is that when...

  8. 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...

  9. 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...

  10. An Application of Passive Samplers to Understand Atmospheric Mercury Concentration and Dry Deposition Spatial Distributions

    Science.gov (United States)

    Two modified passive samplers were evaluated at multiple field locations. The sampling rate (SR) of the modified polyurethane foam (PUF)-disk passive sampler for total gaseous mercury (TGM) using gold-coated quartz fiber filters (GcQFF) and gaseous oxidized mercury (GOM) using io...

  11. Gradient-based MCMC samplers for dynamic causal modelling.

    Science.gov (United States)

    Sengupta, Biswa; Friston, Karl J; Penny, Will D

    2016-01-15

    In this technical note, we derive two MCMC (Markov chain Monte Carlo) samplers for dynamic causal models (DCMs). Specifically, we use (a) Hamiltonian MCMC (HMC-E) where sampling is simulated using Hamilton's equation of motion and (b) Langevin Monte Carlo algorithm (LMC-R and LMC-E) that simulates the Langevin diffusion of samples using gradients either on a Euclidean (E) or on a Riemannian (R) manifold. While LMC-R requires minimal tuning, the implementation of HMC-E is heavily dependent on its tuning parameters. These parameters are therefore optimised by learning a Gaussian process model of the time-normalised sample correlation matrix. This allows one to formulate an objective function that balances tuning parameter exploration and exploitation, furnishing an intervention-free inference scheme. Using neural mass models (NMMs)-a class of biophysically motivated DCMs-we find that HMC-E is statistically more efficient than LMC-R (with a Riemannian metric); yet both gradient-based samplers are far superior to the random walk Metropolis algorithm, which proves inadequate to steer away from dynamical instability.

  12. Symmetrized Importance Samplers for Uncertainty Quantification and Data Assimilation

    Science.gov (United States)

    Leach, A.; Lin, K. K.; Morzfeld, M.

    2016-12-01

    Generating weighted samples from a given probability density by importance sampling is a central step in many algorithms for uncertainty quantification and data assimilation, e.g. for particle filters and rare event sampling. A challenge for importance sampling is to maintain good performance in the limit of small noise, in particular ensuring that the relative variance of the weights do not diverge as noise amplitude decreases. In recent years, a number of researchers have proposed novel importance sampling methods for stochastic differential equations in the low-noise regime. These methods have provably good performance in this setting, and can be used as part of particle filters and other data assimilation methods. Here, we build on these advances to propose and compare a number of importance samplers. We study the weight variance of these methods in a small-noise analysis. We show that samplers with a judicious choice of proposal density can have weight variance that scales linearly with noise amplitude. Furthermore, we show that a general symmetrization procedure can be applied to such first-order methods to produce second-order-accurate methods.

  13. Silica Measurement with High Flow Rate Respirable Size Selective Samplers: A Field Study.

    Science.gov (United States)

    Lee, Taekhee; Harper, Martin; Kashon, Michael; Lee, Larry A; Healy, Catherine B; Coggins, Marie A; Susi, Pam; O'Brien, Andrew

    2016-04-01

    High and low flow rate respirable size selective samplers including the CIP10-R (10 l min(-1)), FSP10 (11.2 l min(-1)), GK2.69 (4.4 l min(-1)), 10-mm nylon (1.7 l min(-1)), and Higgins-Dewell type (2.2 l min(-1)) were compared via side-by-side sampling in workplaces for respirable crystalline silica measurement. Sampling was conducted at eight different occupational sites in the USA and five different stonemasonry sites in Ireland. A total of 536 (268 pairs) personal samples and 55 area samples were collected. Gravimetric analysis was used to determine respirable dust mass and X-ray diffraction analysis was used to determine quartz mass. Ratios of respirable dust mass concentration, quartz mass concentration, respirable dust mass, and quartz mass from high and low flow rate samplers were compared. In general, samplers did not show significant differences greater than 30% in respirable dust mass concentration and quartz mass concentration when outliers (ratio 3.0) were removed from the analysis. The frequency of samples above the limit of detection and limit of quantification of quartz was significantly higher for the CIP10-R and FSP10 samplers compared to low flow rate samplers, while the GK2.69 cyclone did not show significant difference from low flow rate samplers. High flow rate samplers collected significantly more respirable dust and quartz than low flow rate samplers as expected indicating that utilizing high flow rate samplers might improve precision in quartz measurement. Although the samplers did not show significant differences in respirable dust and quartz concentrations, other practical attributes might make them more or less suitable for personal sampling.

  14. [Volatile organic compounds (VOCs) emitted from wood furniture--estimation of emission rate by passive flux sampler].

    Science.gov (United States)

    Jinno, Hideto; Tanaka-Kagawa, Toshiko; Furuta, Mitsuko; Shibatsuji, Masayoshi; Nishimura, Tetsuji

    2011-01-01

    The aim of this study was to evaluate aldehydes and other volatile organic compounds (VOCs) emission from furniture, which may cause hazardous influence on human being such as sick building/sick house syndrome. In this study, VOCs emitted from six kinds of wood furniture, including three set of dining tables and three beds, were analyzed by large chamber test method (JIS A 1911). Based on the emission rates of total VOCs (TVOC), the impacts on the indoor TVOC was estimated by the simulation model with volume of 20 m3 and ventilation frequency of 0.5 times/h. The estimated increment of formaldehyde were exceeded the guideline value (100 microg/m3) in one set of dining table and one bed. The estimated TVOC increment values were exceeded the provisional target value for indoor air (400 microg/m3) in two sets of dining tables and two beds. These results revealed that VOC emissions from wood furniture may influence significantly indoor air quality. Also, in this study, to establish the alternative method for large chamber test methods, emission rates from representative five areas of furniture unit were evaluated by passive sampling method using flux sampler and emission rate from full-sized furniture was predicted. Emission rates predicted by flux passive sampler were 10-106% (formaldehyde) and 8-141% (TVOC) of the data measured using large chamber test, respectively.

  15. The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, W.L. [Argonne National Lab., IL (United States). Chemical Technology Div.

    1995-03-01

    This report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume (SA/V) ratio on the corrosion behavior of borosilicate waste glasses. The SA/V ratio affects the rate of glass corrosion through the extent of dilution of corrosion products released from the glass into the leachate solution: glass corrosion products are diluted more in tests conducted at low SA/V ratios than they are in tests conducted at high SA/V ratios. Differences in the solution chemistries generated in tests conducted at different SA/V ratios then affect the observed glass corrosion behavior. Therefore, any testing parameter that affects the solution chemistry will also affect the glass corrosion rate. The results of static leach tests conducted to assess the effects of the SA/V are discussed with regard to the effects of SA/V on the solution chemistry. Test results show several remaining issues with regard to the long-term glass corrosion behavior: can the SA/V ratio be used as an accelerating parameter to characterize the advanced stages of glass corrosion relevant to long disposal times; is the alteration of the glass surface the same in tests conducted at different SA/V, and in tests conducted with monolithic and crushed glass samples; what are the effects of the SA/V and the extent of glass corrosion on the disposition of released radionuclides? These issues will bear on the prediction of the long-term performance of waste glasses during storage. The results of an experimental program conducted at ANL to address these and other remaining issues regarding the effects of SA/V on glass corrosion are described. 288 refs., 59 figs., 16 tabs.

  16. The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, W.L. [Argonne National Lab., IL (United States). Chemical Technology Div.

    1995-03-01

    This report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume (SA/V) ratio on the corrosion behavior of borosilicate waste glasses. The SA/V ratio affects the rate of glass corrosion through the extent of dilution of corrosion products released from the glass into the leachate solution: glass corrosion products are diluted more in tests conducted at low SA/V ratios than they are in tests conducted at high SA/V ratios. Differences in the solution chemistries generated in tests conducted at different SA/V ratios then affect the observed glass corrosion behavior. Therefore, any testing parameter that affects the solution chemistry will also affect the glass corrosion rate. The results of static leach tests conducted to assess the effects of the SA/V are discussed with regard to the effects of SA/V on the solution chemistry. Test results show several remaining issues with regard to the long-term glass corrosion behavior: can the SA/V ratio be used as an accelerating parameter to characterize the advanced stages of glass corrosion relevant to long disposal times; is the alteration of the glass surface the same in tests conducted at different SA/V, and in tests conducted with monolithic and crushed glass samples; what are the effects of the SA/V and the extent of glass corrosion on the disposition of released radionuclides? These issues will bear on the prediction of the long-term performance of waste glasses during storage. The results of an experimental program conducted at ANL to address these and other remaining issues regarding the effects of SA/V on glass corrosion are described. 288 refs., 59 figs., 16 tabs.

  17. Separation of surface, subsurface and volume fatigue damage effects in AISI 348 steel for power plant applications

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Martin; Nowak, David; Walther, Frank [Technical Univ. Dortmund (Germany). Dept. of Materials Test Engineering (WPT); Starke, Peter [Saarland Univ., Saarbruecken (Germany). Chair of Non-Destructive Testing and Quality Assurance; Boller, Christian [Saarland Univ., Saarbruecken (Germany). Chair of Non-Destructive Testing and Quality Assurance; Fraunhofer IZFP, Saarbruecken (Germany)

    2016-08-01

    A wide range of industries including energy, chemistry, pharmacy, textiles, food and drink, pulp and paper, etc. is using stainless steels. Metastable austenitic steels such as used in power plants and chemical industry are subjected to cyclic mechanical and thermal loading in air as well as under the influence of corrosive media. This paper provides an overview on different nondestructive and electrochemical measurement techniques, which allow differentiating fatigue damage effects in total strain controlled multiple and constant amplitude tests with respect to damage appearance on surface, in subsurface area as well as in volume of specimens or components microstructure. In addition to conventional mechanical stress-strain hysteresis curves, electrical resistance, magnetic and open circuit potential measurements have been applied to characterize the cyclic deformation behavior of the metastable austenitic steel AISI 348 (X10CrNiNb18-9) in laboratory air and in distilled water. Based on these results obtained, the paper provides an outlook on the possibility for an efficient (remaining) fatigue life evaluation approach, which is adapted to the needs of the application areas.

  18. Investigation of the boundary layer during the transition from volume to surface dominated H⁻ production at the BATMAN test facility.

    Science.gov (United States)

    Wimmer, C; Schiesko, L; Fantz, U

    2016-02-01

    BATMAN (Bavarian Test Machine for Negative ions) is a test facility equipped with a 18 scale H(-) source for the ITER heating neutral beam injection. Several diagnostics in the boundary layer close to the plasma grid (first grid of the accelerator system) followed the transition from volume to surface dominated H(-) production starting with a Cs-free, cleaned source and subsequent evaporation of caesium, while the source has been operated at ITER relevant pressure of 0.3 Pa: Langmuir probes are used to determine the plasma potential, optical emission spectroscopy is used to follow the caesiation process, and cavity ring-down spectroscopy allows for the measurement of the H(-) density. The influence on the plasma during the transition from an electron-ion plasma towards an ion-ion plasma, in which negative hydrogen ions become the dominant negatively charged particle species, is seen in a strong increase of the H(-) density combined with a reduction of the plasma potential. A clear correlation of the extracted current densities (j(H(-)), j(e)) exists with the Cs emission.

  19. Investigation of the boundary layer during the transition from volume to surface dominated H- production at the BATMAN test facility

    Science.gov (United States)

    Wimmer, C.; Schiesko, L.; Fantz, U.

    2016-02-01

    BATMAN (Bavarian Test Machine for Negative ions) is a test facility equipped with a 1/8 scale H- source for the ITER heating neutral beam injection. Several diagnostics in the boundary layer close to the plasma grid (first grid of the accelerator system) followed the transition from volume to surface dominated H- production starting with a Cs-free, cleaned source and subsequent evaporation of caesium, while the source has been operated at ITER relevant pressure of 0.3 Pa: Langmuir probes are used to determine the plasma potential, optical emission spectroscopy is used to follow the caesiation process, and cavity ring-down spectroscopy allows for the measurement of the H- density. The influence on the plasma during the transition from an electron-ion plasma towards an ion-ion plasma, in which negative hydrogen ions become the dominant negatively charged particle species, is seen in a strong increase of the H- density combined with a reduction of the plasma potential. A clear correlation of the extracted current densities (jH-, je) exists with the Cs emission.

  20. Facile spray-coating process for the fabrication of tunable adhesive superhydrophobic surfaces with heterogeneous chemical compositions used for selective transportation of microdroplets with different volumes.

    Science.gov (United States)

    Li, Jian; Jing, Zhijiao; Zha, Fei; Yang, Yaoxia; Wang, Qingtao; Lei, Ziqiang

    2014-06-11

    In this paper, tunable adhesive superhydrophobic ZnO surfaces have been fabricated successfully by spraying ZnO nanoparticle (NP) suspensions onto desired substrates. We regulate the spray-coating process by changing the mass percentage of hydrophobic ZnO NPs (which were achieved by modifying hydrophilic ZnO NPs with stearic acid) in the hydrophobic/hydrophilic ZnO NP mixtures to control heterogeneous chemical composition of the ZnO surfaces. Thus, the water adhesion on the same superhydrophobic ZnO surface could be effectively tuned by controlling the surface chemical composition without altering the surface morphology. Compared with the conventional tunable adhesive superhydrophobic surfaces, on which there were only three different water sliding angle values: lower than 10°, 90° (the water droplet is firmly pinned on the surface at any tilted angles), and the value between the two ones, the water adhesion on the superhydrophobic ZnO surfaces has been tuned effectively, on which the sliding angle is controlled from 2 ± 1° to 9 ± 1°, 21 ± 2°, 39 ± 3°, and 90°. Accordingly, the adhesive force can be adjusted from extremely low (∼2.5 μN) to very high (∼111.6 μN). On the basis of the different adhesive forces of the tunable adhesive superhydrophobic surfaces, the selective transportation of microdroplets with different volumes was achieved, which has never been reported before. In addition, we demonstrated a proof of selective transportation of microdroplets with different volumes for application in the droplet-based microreactors via our tunable adhesive superhydrophobic surfaces for the quantitative detection of AgNO3 and NaOH. The results reported herein realize the selective transportation of microdroplets with different volumes and we believe that this method would potentially be used in many important applications, such as selective water droplet transportation, biomolecular quantitative detection and droplet-based biodetection.

  1. Determination of the Surface and Volume Porosity, on the Basis of the Main Fraction of the Polifractional Matrix of Moulding and Core Sands

    Directory of Open Access Journals (Sweden)

    Dańko R.

    2016-12-01

    Full Text Available The aim of the hereby paper is to present the developed model of determining the volume and surface porosity based on the main fraction of polifractional materials, its experimental verification and utilisation for the interpretation of effects accompanying the formation of a moulding sand apparent density, porosity and permeability in the blowing processes of the core and moulds technology.

  2. Guidelines for the use of the semipermeable membrane device (SPMD) and the polar organic chemical integrative sampler (POCIS) in environmental monitoring studies

    Science.gov (United States)

    Alvarez, David A.

    2010-01-01

    The success of an environmental monitoring study using passive samplers, or any sampling method, begins in the office or laboratory. Regardless of the specific methods used, the general steps include the formulation of a sampling plan, training of personnel, performing the field (sampling) work, processing the collected samples to recover chemicals of interest, analysis of the enriched extracts, and interpretation of the data. Each of these areas will be discussed in the following sections with emphasis on specific considerations with the use of passive samplers. Water is an extremely heterogeneous matrix both spatially and temporally (Keith, 1991). The mixing and distribution of dissolved organic chemicals in a water body are controlled by the hydrodynamics of the water, the sorption partition coefficients of the chemicals, and the amount of organic matter (suspended sediments, colloids, and dissolved organic carbon) present. In lakes and oceans, stratification because of changes in temperature, water movement, and water composition can occur resulting in dramatic changes in chemical concentrations with depth (Keith, 1991). Additional complications related to episodic events, such as surface runoff, spills, and other point source contamination, can result in isolated or short-lived pulses of contaminants in the water. The application of passive sampling technologies for the monitoring of legacy and emerging organic chemicals in the environment is becoming widely accepted worldwide. The primary use of passive sampling methods for environmental studies is in the area of surface-water monitoring; however, these techniques have been applied to air and groundwater monitoring studies. Although these samplers have no mechanical or moving parts, electrical or fuel needs which require regular monitoring, there are still considerations that need to be understood in order to have a successful study. Two of the most commonly used passive samplers for organic contaminants are

  3. Field tests of nylon-screen diffusion samplers and pushpoint samplers for detection of metals in sediment pore water, Ashland and Clinton, Massachusetts, 2003

    Science.gov (United States)

    Zimmerman, Marc J.; Vroblesky, Don A.; Campo, Kimberly W.; Massey, Andrew J.; Scheible, Walter

    2005-01-01

    Efficient and economical screening methods are needed to detect and to determine the approximate concentrations of potentially toxic trace-element metals in shallow groundwater- discharge areas (pore water) where the metals may pose threats to aquatic organisms; such areas are likely to be near hazardous-waste sites. Pushpoint and nylon-screen diffusion samplers are two complementary options for use in such environments. The pushpoint sampler, a simple well point, is easy to insert manually and to use. Only 1 day is required to collect samples. The nylon-screen diffusion sampler is well suited for use in sediments that do not allow a pump to draw water into a pushpoint sampler. In this study, both types of devices were used in sediments suitable for the use of the pushpoint sampler. Sampling with the nylon-screen diffusion sampler requires at least two site visits: one to deploy the samplers in the sediment, and a second to retrieve the samplers and collect the samples after a predetermined equilibration period. Extensive laboratory quality-control studies, field testing, and laboratory analysis of samples collected at the Nyanza Chemical Waste Dump Superfund site along the Sudbury River in Ashland, Massachusetts, and at a Superfund site-assessment location on Rigby Brook in Clinton, Massachusetts, indicate that these two devices yield comparable results for most metals and should be effective tools for pore-water studies. The nylon-screen diffusion samplers equilibrated within 1-2 days in homogeneous, controlled conditions in the laboratory. Nylon-screen diffusion samplers that were not purged of dissolved oxygen prior to deployment yielded results similar to those that were purged. Further testing of the nylon-screen diffusion samplers in homogeneous media would help to resolve any ambiguities about the data variability from the field studies. Comparison of data from replicate samples taken in both study areas shows that even samples taken from sites within a

  4. Particle-into-Liquid Sampler (PILS) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Thomas B [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    The Particle-into-Liquid Sampler (PILS) is an aqueous-solution-based online technique for determining bulk chemical composition of ambient aerosol particles. As shown in Figure 1, the instrument consists of two units, briefly described below: 1. An aerosol extraction unit where particles are passed through a growth chamber saturated with water vapor, liquid droplets are grown, and the resulting liquid collected and transferred to the detection system. 2. The detection system that includes ion chromatographs (IC) or a total organic carbon detector (TOC). Ion chromatography is performed using two Metrohm ICs—one for positive ions and one for negative ions—with conductivity detectors. The TOC is detected using a GE TOC analyzer. The instrument can be run in either the ion detection mode or the TOC mode.

  5. 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 important because the lapel has always been the sampling location for coal mine dust samples. But these results suggest that the cap location is slightly more indicative of what is breathed through the nose area.

  6. Sampling errors in pH and blood gas analysis--an evaluation of three new arterial blood samplers.

    Science.gov (United States)

    Hutchison, A S; Dryburgh, F J; Ralston, S H

    1986-05-01

    We have tested the accuracy, acceptability and general performance of three recently-marketed samplers for arterial blood gas measurement (the Corning Arterial Blood Sampler, the Concord 'Pulsator' and the Sarstedt 'Monovette'). All three greatly reduce or eliminate the error of venous sampling, and the Corning and Sarstedt samplers eliminate the risk of dilution of the sample by excess heparin solution. A positive bias in pO2 measurement, more marked at higher levels, was demonstrated with the Concord and Sarstedt samplers, and the latter carry a slightly increased risk of cross-infection. None of the samplers completely overcame potential sampling errors.

  7. 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.

  8. An Affine-invariant Sampler for Exoplanet Fitting and Discovery in Radial Velocity Data

    Science.gov (United States)

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

    2012-02-01

    Markov chain Monte Carlo (MCMC) proves to be powerful for Bayesian inference and in particular for exoplanet radial velocity fitting because MCMC provides more statistical information and makes better use of data than common approaches like chi-square fitting. However, the nonlinear density functions encountered in these problems can make MCMC time-consuming. In this paper, we apply an ensemble sampler respecting affine invariance to orbital parameter extraction from radial velocity data. This new sampler has only one free parameter, and does not require much tuning for good performance, which is important for automatization. The autocorrelation time of this sampler is approximately the same for all parameters and far smaller than Metropolis-Hastings, which means it requires many fewer function calls to produce the same number of independent samples. The affine-invariant sampler speeds up MCMC by hundreds of times compared with Metropolis-Hastings in the same computing situation. This novel sampler would be ideal for projects involving large data sets such as statistical investigations of planet distribution. The biggest obstacle to ensemble samplers is the existence of multiple local optima; we present a clustering technique to deal with local optima by clustering based on the likelihood of the walkers in the ensemble. We demonstrate the effectiveness of the sampler on real radial velocity data.

  9. In situ calibration of three passive samplers for the monitoring of steroid hormones in wastewater.

    Science.gov (United States)

    Škodová, Alena; Prokeš, Roman; Šimek, Zdeněk; Vrana, Branislav

    2016-12-01

    In situ extraction of steroid hormones from waste water using adsorption-based integrative passive samplers represents a promising approach for their monitoring in water at ultra-trace concentrations. Three passive samplers, namely a POCIS, a Chemcatcher fitted with an Empore SDB-RPS disk, and an Empore SDB-RPS disk-based sampler with enhanced water flow, were calibrated in situ in treated municipal wastewater for the purpose of monitoring five estrogens (17-β-estradiol, 17-α-estradiol, 17-α-ethinylestradiol, estrone and estriol) at sub ng per litre concentrations. Uptake of steroids to samplers during 14-day exposure in wastewater was compared with steroid concentrations in daily collected composite water samples. Sampling rates were obtained from a numerical solution of first order uptake kinetics equations describing the uptake of compounds into a passive sampler over time. Mass transfer of steroids in the Chemcatcher fitted with naked Empore disks was more than two times faster than in the POCIS sampler. The uptake capacity of the applied Empore disk was not sufficient for integrative uptake of all tested steroids during the entire 14-day exposure. Time-weighted average concentrations of steroids estimated at concentrations in units of ngL(-1) using the in situ-calibrated samplers were within a factor of two from values obtained using composite water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hou Fengji; Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Goodman, Jonathan; Weare, Jonathan [Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY 10012 (United States); Schwab, Christian, E-mail: fh417@nyu.edu [Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States)

    2012-02-01

    Markov chain Monte Carlo (MCMC) proves to be powerful for Bayesian inference and in particular for exoplanet radial velocity fitting because MCMC provides more statistical information and makes better use of data than common approaches like chi-square fitting. However, the nonlinear density functions encountered in these problems can make MCMC time-consuming. In this paper, we apply an ensemble sampler respecting affine invariance to orbital parameter extraction from radial velocity data. This new sampler has only one free parameter, and does not require much tuning for good performance, which is important for automatization. The autocorrelation time of this sampler is approximately the same for all parameters and far smaller than Metropolis-Hastings, which means it requires many fewer function calls to produce the same number of independent samples. The affine-invariant sampler speeds up MCMC by hundreds of times compared with Metropolis-Hastings in the same computing situation. This novel sampler would be ideal for projects involving large data sets such as statistical investigations of planet distribution. The biggest obstacle to ensemble samplers is the existence of multiple local optima; we present a clustering technique to deal with local optima by clustering based on the likelihood of the walkers in the ensemble. We demonstrate the effectiveness of the sampler on real radial velocity data.

  11. ExperienceSampler: An Open-Source Scaffold for Building Smartphone Apps for Experience Sampling.

    Science.gov (United States)

    Thai, Sabrina; Page-Gould, Elizabeth

    2017-06-15

    Experience sampling methods allow researchers to examine phenomena in daily life and provide various advantages that complement traditional laboratory methods. However, existing experience sampling methods may be costly, require constant Internet connectivity, may not be designed specifically for experience sampling studies, or require a custom solution from a computer programming consultant. In this article, we present ExperienceSampler, an open-source scaffold for creating experience-sampling smartphone apps designed for Android and iOS devices. We designed ExperienceSampler to address the common barriers to using experience sampling methods. First, there is no cost to the user. Second, ExperienceSampler apps make use of local notifications to let participants know when to complete surveys and store the data locally until Internet connection is available. Third, our app scaffold was designed with experience sampling methodological issues in mind. We also demonstrate how researchers can easily customize ExperienceSampler even if they have no programming skills. Furthermore, we evaluate the utility of ExperienceSampler apps with results from one social psychological study conducted using ExperienceSampler (N = 168). Mean response rates averaged 84%, and the median response latency was 9 minutes. Taken together, ExperienceSampler creates cost-effective smartphone apps that can be easily customized by researchers to examine experiences in daily life. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  12. Evaluation of the polyurethane foam (PUF) disk passive air sampler: Computational modeling and experimental measurements

    Science.gov (United States)

    May, Andrew A.; Ashman, Paul; Huang, Jiaoyan; Dhaniyala, Suresh; Holsen, Thomas M.

    2011-08-01

    Computational fluid dynamics (CFD) simulations coupled with wind tunnel-experiments were used to determine the sampling rate (SR) of the widely used polyurethane foam (PUF) disk passive sampler. In the wind-tunnel experiments, water evaporation rates from a water saturated PUF disk installed in the sampler housing were determined by measuring weight loss over time. In addition, a modified passive sampler designed to collect elemental mercury (Hg 0) with gold-coated filters was used. Experiments were carried out at different wind speeds and various sampler angles. The SRs obtained from wind-tunnel experiments were compared to those obtained from the field by scaling the values by the ratios of air diffusivities. Three-dimensional (3D) CFD simulations were also used to generate SRs for both polychlorinated biphenyls (PCBs) and Hg 0. Overall, the modeled and measured SRs agree well and are consistent with the values obtained from field studies. As previously observed, the SRs increased linearly with increasing wind speed. In addition, it was determined that the SR was strongly dependent on the angle of the ambient wind. The SRs increased when the base was tilted up pointing into the wind and when the base was tilted down (i.e., such that the top of the sampler was facing the wind) the SR decreased initially and then increased. The results suggest that there may be significant uncertainty in concentrations obtained from passive sampler measurements without knowledge of wind speed and wind angle relative to the sampler.

  13. Design and evaluation of an exhaled breath sampler for biological monitoring of organic solvents.

    Science.gov (United States)

    Periago, J F; Luna, A; Morente, A; Zambudio, A

    1992-04-01

    We designed a breath sampler based on a tube which collects the final portion of exhaled air. The passage of successive fractions through a layer of activated charcoal is controlled by a three-way valve. This system was validated in a controlled atmosphere of n-hexane and toluene at four concentrations between 12 and 110 mg m-3 and 12 and 115 mg m-3, respectively. Uptake volumes of 0.1, 0.2 and 0.31 were tested at relative humidities of 46% and 98%. There were no significant differences in the recoveries obtained under any of the conditions tested. We confirmed the reproducibility between successive samples in volunteers and exposed workers, and found no significant differences between the different sampling conditions studied. Our system enriches the sample in an adsorbent cartridge by collecting successive fractions of end-exhaled breath from one or more exhalations until the amount required by the analytical method has been accumulated. It is portable, economical and highly operative in the field.

  14. A study of aerosol entrapment and the influence of wind speed, chamber design and foam density on polyurethane foam passive air samplers used for persistent organic pollutants.

    Science.gov (United States)

    Chaemfa, Chakra; Wild, Edward; Davison, Brian; Barber, Jonathan L; Jones, Kevin C

    2009-06-01

    Polyurethane foam disks are a cheap and versatile tool for sampling persistent organic pollutants (POPs) from the air in ambient, occupational and indoor settings. This study provides important background information on the ways in which the performance of these commonly used passive air samplers may be influenced by the key environmental variables of wind speed and aerosol entrapment. Studies were performed in the field, a wind tunnel and with microscopy techniques, to investigate deployment conditions and foam density influence on gas phase sampling rates (not obtained in this study) and aerosol trapping. The study showed: wind speed inside the sampler is greater on the upper side of the sampling disk than the lower side and tethered samplers have higher wind speeds across the upper and lower surfaces of the foam disk at a wind speed > or = 4 m/s; particles are trapped on the foam surface and within the body of the foam disk; fine (foam matrix. Whilst primarily designed to sample gas phase POPs, entrapment of particles ensures some 'sampling' of particle bound POPs species, such as higher molecular weight PAHs and PCDD/Fs. Further work is required to investigate how quantitative such entrapment or 'sampling' is under different ambient conditions, and with different aerosol sizes and types.

  15. Ink-Jet Printing of Gluconobacter oxydans: Micropatterned Coatings As High Surface-to-Volume Ratio Bio-Reactive Coatings

    Directory of Open Access Journals (Sweden)

    Marcello Fidaleo

    2013-12-01

    Full Text Available We formulated a latex ink for ink-jet deposition of viable Gram-negative bacterium Gluconobacter oxydans as a model adhesive, thin, highly bio-reactive microstructured microbial coating. Control of G. oxydans latex-based ink viscosity by dilution with water allowed ink-jet piezoelectric droplet deposition of 30 × 30 arrays of two or three droplets/dot microstructures on a polyester substrate. Profilometry analysis was used to study the resulting dry microstructures. Arrays of individual dots with base diameters of ~233–241 µm were obtained. Ring-shaped dots with dot edges higher than the center, 2.2 and 0.9 µm respectively, were obtained when a one-to-four diluted ink was used. With a less diluted ink (one-to-two diluted, the microstructure became more uniform with an average height of 3.0 µm, but the ink-jet printability was more difficult. Reactivity of the ink-jet deposited microstructures following drying and rehydration was studied in a non-growth medium by oxidation of 50 g/L D-sorbitol to L-sorbose, and a high dot volumetric reaction rate was measured (~435 g·L−1·h−1. These results indicate that latex ink microstructures generated by ink-jet printing may hold considerable potential for 3D fabrication of high surface-to-volume ratio biocoatings for use as microbial biosensors with the aim of coating microbes as reactive biosensors on electronic devices and circuit chips.

  16. Scaling of volume to surface ratio and doubling time in growing unicellular organisms: Do cells appear quantum-mechanical systems?

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, Atanas Todorov, E-mail: atanastod@abv.bg [Department of Physics and Biophysics, Faculty of Medicine, Trakia University, 11 Armeiska Str., 6000 Stara Zagora (Bulgaria)

    2014-10-06

    The scaling of physical and biological characteristics of the living organisms is a basic method for searching of new biophysical laws. In series of previous studies the author showed that in Poikilotherms, Mammals and Aves, the volume to surface ratio V×S{sup −1} (m) of organisms is proportional to their generation time T{sub gt}(s) via growth rate v (m s{sup −1}): V×S{sup −1} = v{sub gr}×T{sup r}. The power and the correlation coefficients are near to 1.0. Aim of this study is: i) to prove with experimental data the validity of the above equation for Unicellular organisms and ii) to show that perhaps, the cells are quantum-mechanical systems. The data for body mass M (kg), density ρ (kg/m{sup 3}), minimum and maximum doubling time T{sub dt} (s) for 50 unicellular organisms are assembled from scientific sources, and the computer program ‘Statistics’ is used for calculations. In result i) the analytical relationship from type: V×S{sup −1} = 4.46⋅10{sup −11}×T{sub dt} was found, where v{sub gr} = 4.46×10{sup −11} m/s and ii) it is shown that the products between cell mass M, cell length expressed by V/S ratio and growth rate v{sub gr} satisfied the Heisenberg uncertainty principle i.e. the inequalities V/S×M×v{sub gr}>h/2π and T{sub dt}×M×v{sub gr}{sup 2}>h/2π are valid, where h= 6.626×10{sup −34} J⋅s is the Planck constant. This rise the question: do cells appear quantum-mechanical systems?.

  17. Development of an integrated sampler based on direct {sup 222}Rn/{sup 220}Rn progeny sensors in flow-mode for estimating unattached/attached progeny concentration

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Rosaline, E-mail: rosaline@barc.gov.i [Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Sapra, B.K.; Mayya, Y.S. [Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2009-11-15

    A flow-mode integrated sampler consisting of a wire-mesh and filter-paper array along with passive solid state nuclear track detectors has been developed for estimating unattached and attached fraction of {sup 222}Rn/{sup 220}Rn progeny concentration. The essential element of this sampler is the direct {sup 222}Rn/{sup 220}Rn progeny sensor (DRPS/DTPS), which is an absorber-mounted-LR115 type nuclear track detector that selectively registers the alpha particles emitted from the progeny deposited on its surface. During sampling at a specified flow-rate, the unattached progeny is captured on the wire-mesh; while the attached progeny gets transmitted and is captured on the filter-paper. The alpha particles emitted by the deposited progeny atoms are registered on the sensors placed at a specified distance facing the wire-mesh and the filter-paper, respectively. The various steps involved in the development of this flow-mode direct progeny sampler such as the optimization of the sampling rate and the distance between the sensor and the deposition substrate are discussed. The sensitivity factor of the DTPS-loaded sampler for {sup 220}Rn progeny deposited on the wire-mesh and filter-paper is found to be 23.77 +- 0.64 (track cm{sup -2} h{sup -1}) (Bq m{sup -3}){sup -1} and 22.30 +- 0.18 (track cm{sup -2} h{sup -1}) (Bq m{sup -3}){sup -1}, respectively; while that of DRPS-loaded sampler for {sup 222}Rn progeny deposition, is 3.03 +- 0.14 (track cm{sup -2} h{sup -1}) (Bq m{sup -3}){sup -1} and 2.08 +- 0.07 (track cm{sup -2} h{sup -1}) (Bq m{sup -3}){sup -1}, respectively. The highlight of this flow-mode sampler is its high sensitivity and that it utilizes the passive technique for estimating the unattached and attached progeny concentration, thus doing away with the alpha counting procedures.

  18. Development of a compressive surface capturing formulation for modelling free-surface flow by using the volume-of-fluid approach

    CSIR Research Space (South Africa)

    Heyns, Johan A

    2012-06-01

    Full Text Available combines a blended higher resolution scheme with the addition of an artificial compressive term to the volume-of-fluid equation. This reduces the numerical smearing of the interface associated with explicit higher resolution schemes while limiting...

  19. Cortical and Subcortical Structural Plasticity Associated with the Glioma Volumes in Patients with Cerebral Gliomas Revealed by Surface-Based Morphometry

    Directory of Open Access Journals (Sweden)

    Jinping Xu

    2017-06-01

    Full Text Available Postlesional plasticity has been identified in patients with cerebral gliomas by inducing a large functional reshaping of brain networks. Although numerous non-invasive functional neuroimaging methods have extensively investigated the mechanisms of this functional redistribution in patients with cerebral gliomas, little effort has been made to investigate the structural plasticity of cortical and subcortical structures associated with the glioma volume. In this study, we aimed to investigate whether the contralateral cortical and subcortical structures are able to actively reorganize by themselves in these patients. The compensation mechanism following contralateral cortical and subcortical structural plasticity is considered. We adopted the surface-based morphometry to investigate the difference of cortical and subcortical gray matter (GM volumes in a cohort of 14 healthy controls and 13 patients with left-hemisphere cerebral gliomas [including 1 patients with World Health Organization (WHO I, 8 WHO II, and 4 WHO III]. The glioma volume ranges from 5.1633 to 208.165 cm2. Compared to healthy controls, we found significantly increased GM volume of the right cuneus and the left thalamus, as well as a trend toward enlargement in the right globus pallidus in patients with cerebral gliomas. Moreover, the GM volumes of these regions were positively correlated with the glioma volumes of the patients. These results provide evidence of cortical and subcortical enlargement, suggesting the usefulness of surface-based morphometry to investigate the structural plasticity. Moreover, the structural plasticity might be acted as the compensation mechanism to better fulfill its functions in patients with cerebral gliomas as the gliomas get larger.

  20. Application of XAD-2 resin-based passive samplers and SPME-GC-MS/MS analysis for the monitoring of spatial and temporal variations of atmospheric pesticides in Luxembourg.

    Science.gov (United States)

    Schummer, Claude; Tuduri, Ludovic; Briand, Olivier; Appenzeller, Brice M; Millet, Maurice

    2012-11-01

    Passive air sampling has been shown to be a very interesting alternative to high-volume sampling by overcoming its disadvantages (size, weight, expensiveness). However, to date, only limited data is available about passive air sampling of current-use pesticides. In order to test if passive samplers allow monitoring of spatial and temporal variations of atmospheric pesticide concentrations, five XAD-2-resin based passive air samplers were deployed at five locations in Luxembourg. Samplers were analyzed using accelerated solvent extraction coupled to solid-phase microextraction and gas chromatography with tandem mass spectrometry. Collected data was used to study the spatial and temporal variations of the concentrations of the compounds. Twenty two pesticides were detected between March and October, while no pesticides were detected from November to February. Highest concentrations were measured on the rural sites, suggesting that the used XAD-2 resin-based passive samplers allow the simultaneous monitoring of multiple current-use pesticides and identifying spatial and temporal variations.

  1. Characterization and Application of Passive Samplers for Monitoring of Pesticides in Water.

    Science.gov (United States)

    Ahrens, Lutz; Daneshvar, Atlasi; Lau, Anna E; Kreuger, Jenny

    2016-08-03

    Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study provides a protocol for the passive sampler preparation, calibration, extraction method and instrumental analysis. Sampling rates (RS) and passive sampler-water partition coefficients (KPW) were calculated for silicone rubber, polar organic chemical integrative sampler POCIS-A, POCIS-B, SDB-RPS and C18 disk. The uptake of the selected compounds depended on their physicochemical properties, i.e., silicone rubber showed a better uptake for more hydrophobic compounds (log octanol-water partition coefficient (KOW) > 5.3), whereas POCIS-A, POCIS-B and SDB-RPS disk were more suitable for hydrophilic compounds (log KOW < 0.70).

  2. AirCore Reusable InSitu Sampler for CO2 and Trace Gas Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The AirCore is a simple and novel atmospheric air column sampler to validate satellite observation data of greenhouse gases, using a lightweight, inexpensive coated...

  3. An Affine-Invariant Sampler for Exoplanet Fitting and Discovery in Radial Velocity Data

    CERN Document Server

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

    2011-01-01

    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 non-linear 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. 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. Besides being fast, the new sampler has only one free parameter, and it does not require tuning for good performance, which is important for automatization. This novel ...

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

    Science.gov (United States)

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

    2012-11-01

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

  5. Novel Highly Efficient Compact Rotary-Hammering Planetary Sampler Actuated by a Single Piezoelectric Actuator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We had two objectives in this task: 1. Develop effective single low-mass, low-power piezoelectric drive that can actuate rotary-hammer samplers through walls. 2....

  6. Least Squares Best Fit Method for the Three Parameter Weibull Distribution: Analysis of Tensile and Bend Specimens with Volume or Surface Flaw Failure

    Science.gov (United States)

    Gross, Bernard

    1996-01-01

    Material characterization parameters obtained from naturally flawed specimens are necessary for reliability evaluation of non-deterministic advanced ceramic structural components. The least squares best fit method is applied to the three parameter uniaxial Weibull model to obtain the material parameters from experimental tests on volume or surface flawed specimens subjected to pure tension, pure bending, four point or three point loading. Several illustrative example problems are provided.

  7. The DOE Automated Radioxenon Sampler-Analyzer (ARSA) Beta-Gamma Coincidence Spectrometer Data Analyzer

    Science.gov (United States)

    2000-09-01

    detected using the counting system given the daily fluctuations in Radon gas interference, the background counts, the memory effect of previous...THE DOE AUTOMATED RADIOXENON SAMPLER-ANALYZER (ARSA) BETA-GAMMA COINCIDENCE SPECTROMETER DATA ANALYZER T.R. Heimbigner, T.W. Bowyer, J.I...1830 ABSTRACT The Automated Radioxenon Sampler/Analyzer (ARSA) developed at the Pacific Northwest National Laboratory for the Comprehensive

  8. Excluded volume effect of counterions and water dipoles near a highly charged surface due to a rotationally averaged Boltzmann factor for water dipoles.

    Science.gov (United States)

    Gongadze, Ekaterina; Iglič, Aleš

    2013-03-01

    Water ordering near a negatively charged electrode is one of the decisive factors determining the interactions of an electrode with the surrounding electrolyte solution or tissue. In this work, the generalized Langevin-Bikerman model (Gongadze-Iglič model) taking into account the cavity field and the excluded volume principle is used to calculate the space dependency of ions and water number densities in the vicinity of a highly charged surface. It is shown that for high enough surface charged densities the usual trend of increasing counterion number density towards the charged surface may be completely reversed, i.e. the drop in the counterions number density near the charged surface is predicted.

  9. The alterations of cortical volume, thickness, surface and density in the intermediate sporadic Parkinson's disease from the Han population of Mainland China

    Directory of Open Access Journals (Sweden)

    Xia Deng

    2016-08-01

    Full Text Available Many symptoms of sporadic Parkinson's disease (sPD can’t be completely explained by the lesion of simple typical extrapyramidal circuit between striatum and substantia nigra. Therefore, we investigated the alteration of cortical volume, thickness, surface and density in the intermediate sPD from the Han population of Mainland China in order to find the new pathological brain regions associated with the complex clinical manifestations of sPD. The cortical volume, thickness, surface and density were examined using the voxel-based cortical morphometry and corticometry on magnetic resonance image (MRI in 67 intermediate sPD and 35 controls, the multiple adjusted comparisons analysis of all MRI data were employed to assess the relationships between the cortical morphometric alteration in the specific brain regions and sPD. Results showed that a significantly shrunk volume, thinned thickness and enlarged or reduced surface of cortex in some specific brain regions were closely associated with sPD, but all cortical densities were not different. The majority of morphometric alteration of hemisphere cortex was symmetric, but that in the left hemisphere was more significant. The cortical morphometric alterations in the frontal, temporal, parietal, occipital and limbic lobe, cerebellum, caudate and thalamus were closely related to the clinical neural dysfunction (Clinical manifestations of sPD. Our data indicated that the deficits of extensive brain regions involved in the development of sPD, resulted in a series of correspondent complex clinical manifestations in the disease.

  10. Surface Environmental Surveillance Project: Locations Manual Volume 1 – Air and Water Volume 2 – Farm Products, Soil & Vegetation, and Wildlife

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, Brad G.; Patton, Gregory W.; Stegen, Amanda; Poston, Ted M.

    2009-01-01

    This report describes all environmental monitoring locations associated with the Surface Environmental Surveillance Project. Environmental surveillance of the Hanford site and surrounding areas is conducted by the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE). Sampling is conducted to evaluate levels of radioactive and nonradioactive pollutants in the Hanford environs, as required in DOE Order 450.1, Environmental Protection Program, and DOE Order 5400.5, Radiation Protection of the Public and the Environment. The environmental surveillance sampling design is described in the Hanford Site Environmental Monitoring Plan, United States Department of Energy, Richland Operation Office (DOE/RL-91-50). This document contains the locations of sites used to collect samples for the Surface Environmental Surveillance Project (SESP). Each section includes directions, maps, and pictures of the locations. A general knowledge of roads and highways on and around the Hanford Site is necessary to successfully use this manual. Supplemental information (Maps, Gazetteer, etc.) may be necessary if user is unfamiliar with local routes. The SESP is a multimedia environmental surveillance effort to measure the concentrations of radionuclides and chemicals in environmental media to demonstrate compliance with applicable environmental quality standards and public exposure limits, and assessing environmental impacts. Project personnel annually collect selected samples of ambient air, surface water, agricultural products, fish, wildlife, and sediments. Soil and vegetation samples are collected approximately every 5 years. Analytical capabilities include the measurement of radionuclides at very low environmental concentrations and, in selected media, nonradiological chemicals including metals, anions, volatile organic compounds, and total organic carbon.

  11. Study on the Thermal Insulation Performance of a New Seabed Sediment Fidelity Sampler Based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    LIU Guoying; LIU Guijie; YUAN Weijie

    2009-01-01

    A new seabed sediment fidelity sampler was developed and its thermal insulation performance was studied and analyzed.The temperature distribution simulation indicated that the sample quality could be insured by using this new sampler. Based on ANSYS10, the temperature finite element model of the sample cylinder was established. According to the law of conservation of energy, the unsteady heat transmit equation of the sampler under solid-liquid coupling condition was derived, then the mathematical model calculation was carried out by using a mixed finite-element finite-difference method, and two thermal insulation methods were used. The simulation was carried out by using the thickness of the thermal insulation layer and heat conductivity as the variable parameters and the temperature distribution of the sampler and related influencing factors were obtained. Optimization analysis was conducted using the simulation data and related parameters and the magnitude ranges of the parameters were obtained that could meet the design temperature requirements. The experimental data and simulation results indicated that the results were in good agreement with the realities, and this sampler might be of value for seabed sediment sampler design and manufacture.

  12. 基于 CUDA 的细分曲面阴影体算法%CUDA based shadow volume algorithm for subdivision surfaces

    Institute of Scientific and Technical Information of China (English)

    赵杰伊; 唐敏; 童若锋

    2012-01-01

    为了在虚拟现实、电脑游戏等图形应用中更快速生成和实时绘制细分曲面的阴影,提出采用CUDA架构的GPU阴影体生成算法.该算法采用基于CUDA的曲面细分算法,通过CUDA共享内存结构使表面细分过程更加高效.采用基于CUDA的阴影体算法产生阴影轮廓线以及拉伸出阴影体.通过基于CUDA的流式缩减算法对阴影体数组进行压缩.通过优化CUDA和OpenGL的互操作,将绘制过程从以往算法的3步减少为2步.该算法在具有CUDA硬件的标准PC上进行测试.实验结果表明,与之前的GPU的算法相比,该算法可以生成更复杂细分曲面的阴影体,阴影体数组占用显存空间降低到2%以下,并可获得高达4倍的绘制速度提升.%A new GPU based shadow volume generation algorithm based on CUDA structure was proposed for fast generation and real-time rendering of shadow of subdivision surfaces in computer games and virtual reality applications. The algorithm introduces CUDA-based surface subdivision algorithm. Generation of surface subdivisions can run faster by using shared memory structure. CUDA-based shadow volume algorithm was introduced to generate the shadow silhouette line and extrude the shadow volume. CUDA-based stream reduction algorithm was introduced to reduce the shadow volume array. An optimized interopera-tion between CUDA and OPENGL was introduced to simplify the rendering step of the algorithm from three steps to two steps. Implemented on a standard PC with CUDA hardware, experiments show that the algorithm can generate the shadow volume of more complex subdivision surfaces compared with former GPU-based ones. The algorithm needs smaller video memory for the shadow volume array to less than 2%, and the rendering performance can gain acceleration up to more than four times.

  13. A method for targeting air samplers for facility monitoring in an urban environment

    Science.gov (United States)

    Bieringer, Paul E.; Longmore, Scott; Bieberbach, George; Rodriguez, Luna M.; Copeland, Jeff; Hannan, John

    2013-12-01

    There are a variety of applications that require the use of comprehensive specification of the weather conditions combined with an analysis that uses detailed modeling and simulation. The combination of these two elements can make it difficult to achieve the desired level of fidelity in a logistically feasible way. An example of this type of application is the deployment of surface-based sensors/samplers, which is a common practice for emission, and air quality monitoring purposes where the proper selection of sites for the measurement equipment is critical to an accurate characterization of the emissions. This is particularly true in urban environments where the limited availability of suitable sites and the non-intuitive dispersion patterns associated with the wind flow around the buildings and through the urban canyons make site selection difficult. This article demonstrates an improved methodology for optimally locating for air quality monitoring equipment within this complex and challenging environment. The methodology involves a) the utilization of a longer climatological record of meteorological observations or gridded reanalysis products to better represent the full range of representative meteorological conditions; b) reduction of the full climatological record into a subset of characteristic meteorological patterns and associated frequencies of occurrence, utilizing a multi-dimensional feature extraction and classification technique known as a Self Organizing Map (SOM); c) downscaling and diagnosis of the urban area building-aware wind flow fields for each characteristic meteorological pattern; d) atmospheric transport and dispersion (AT&D) simulations for each downscaled meteorological pattern, utilizing a building aware Lagrangian particle dispersion model; and finally e) the combination of predicted downwind concentrations/dosages for each meteorological pattern with their associated frequency of occurrence are used to generate Probability of Detection

  14. Using structural equation modeling to construct calibration equations relating PM2.5 mass concentration samplers to the federal reference method sampler

    Science.gov (United States)

    Bilonick, Richard A.; Connell, Daniel P.; Talbott, Evelyn O.; Rager, Judith R.; Xue, Tao

    2015-02-01

    The objective of this study was to remove systematic bias among fine particulate matter (PM2.5) mass concentration measurements made by different types of samplers used in the Pittsburgh Aerosol Research and Inhalation Epidemiology Study (PARIES). PARIES is a retrospective epidemiology study that aims to provide a comprehensive analysis of the associations between air quality and human health effects in the Pittsburgh, Pennsylvania, region from 1999 to 2008. Calibration was needed in order to minimize the amount of systematic error in PM2.5 exposure estimation as a result of including data from 97 different PM2.5 samplers at 47 monitoring sites. Ordinary regression often has been used for calibrating air quality measurements from pairs of measurement devices; however, this is only appropriate when one of the two devices (the "independent" variable) is free from random error, which is rarely the case. A group of methods known as "errors-in-variables" (e.g., Deming regression, reduced major axis regression) has been developed to handle calibration between two devices when both are subject to random error, but these methods require information on the relative sizes of the random errors for each device, which typically cannot be obtained from the observed data. When data from more than two devices (or repeats of the same device) are available, the additional information is not used to inform the calibration. A more general approach that often has been overlooked is the use of a measurement error structural equation model (SEM) that allows the simultaneous comparison of three or more devices (or repeats). The theoretical underpinnings of all of these approaches to calibration are described, and the pros and cons of each are discussed. In particular, it is shown that both ordinary regression (when used for calibration) and Deming regression are particular examples of SEMs but with substantial deficiencies. To illustrate the use of SEMs, the 7865 daily average PM2.5 mass

  15. SOLLIMS Sampler: Targeting Peace & Stability Operations Lessons & Best Practices. Volume 3, Issue 2

    Science.gov (United States)

    2012-04-01

    Dr. Roshan, a licensed veterinarian who is part of a team directed by the Kunar provincial veterinarian . (U.S. Air Force photo by Captain Peter...the military leadership of a Provincial Reconstruction Team (PRT) located in Panjshir had planned a program to bring American veterinarians to...Table of Contents | Quick Look | Contact PKSOI Page 27 of 42 USNS Comfort, equipped with surgical operating teams and orthopedic

  16. "PRISTINE", a new high volume sampler for ultraclean sampling of trace metals and isotopes

    NARCIS (Netherlands)

    Rijkenberg, Micha J.A.; de Baar, Hein J.W.; Bakker, Karel; Gerringa, Loes J.A.; Keijzer, Edwin; Laan, Martin; Laan, Patrick; Middag, Rob; Ober, Sven; van Ooijen, Jan; Ossebaar, Sharyn; Weerlee, Evaline M. van; Smit, Marck G.

    2015-01-01

    Many trace elements like Mn, Fe, Co, Ni, Cu and Zn are essential for marine life, some trace elements are of concern as pollutants, e.g. Pb and Hg, while others, together with a diverse array of isotopes, are used to assess modern-ocean processes and the role of the ocean in past climate change.

  17. “PRISTINE”, a new high volume sampler for ultraclean sampling of trace metals and isotopes

    NARCIS (Netherlands)

    Rijkenberg, M.J.; de Baar, H.J.W.; Bakker, K.; Gerringa, L.J.A.; Keijzer, E.; Laan, M.; Laan, P.; Middag, R.; Ober, S.; van Ooijen, J.; Ossebaar, S.; van Weerlee, E.M.; Smit, M.

    2015-01-01

    Many trace elements like Mn, Fe, Co, Ni, Cu and Zn are essential for marine life, some trace elements are of concern as pollutants, e.g. Pb and Hg, while others, together with a diverse array of isotopes, are used to assess modern-ocean processes and the role of the ocean in past climate change. GEO

  18. "PRISTINE", a new high volume sampler for ultraclean sampling of trace metals and isotopes

    NARCIS (Netherlands)

    Rijkenberg, Micha J.A.; de Baar, Hein J.W.; Bakker, Karel; Gerringa, Loes J.A.; Keijzer, Edwin; Laan, Martin; Laan, Patrick; Middag, Rob; Ober, Sven; van Ooijen, Jan; Ossebaar, Sharyn; Weerlee, Evaline M. van; Smit, Marck G.

    2015-01-01

    Many trace elements like Mn, Fe, Co, Ni, Cu and Zn are essential for marine life, some trace elements are of concern as pollutants, e.g. Pb and Hg, while others, together with a diverse array of isotopes, are used to assess modern-ocean processes and the role of the ocean in past climate change. GEO

  19. SOLLIMS Sampler: Targeting Peace & Stability Operations Lessons & Best Practices. Volume 3, Issue 3

    Science.gov (United States)

    2012-07-01

    from crimes of sexual slavery and rape. The peace accord was signed on August 18, 2003, after months of international mediation. It was facilitated by...attainment of several core benchmarks be initiated. UNMIL has implemented measures to prevent, detect, investigate, and punish acts of sexual ...exploitation and abuse (SEA), in line with recent reforms and renewed U.N.-wide regulations regarding sexual conduct, following abuses in several U.N

  20. 40 CFR Appendix III to Part 86 - Constant Volume Sampler Flow Calibration

    Science.gov (United States)

    2010-07-01

    ... monoxide is poisonous!). Critical flow orifice devices can also be used for constant flow metering. 2... fittings on the intake side of sample transfer pumps on both the CVS and analyzer console....

  1. Progress Toward an Enceladus Amino Acid Sampler Astrobiology Instrument

    Science.gov (United States)

    Kirby, J. P.; Willis, P. A.; Blacksberg, J.

    2012-12-01

    The development of a new astrobiolgoy instrument for exploring the trace chemical composition of the Enceladus jets and plume, and the e-ring of Saturn is presented. The Enceladus amino acid sampler (EAAS) allows for detection of amino acids using optical Raman spectroscopy integrated with a sample pre-concentration system. The pre-concentration process facilitates the delivery of a sample to a mass spectrometer for detection of specific amino acids. The initial EAAS design utilizes lab-on-a-breadboard components where a sample inlet, sample outlet, reagents, controllers, pumps, valves and pre-concentration column for the EAAS prototype are all assembled on a 5" x 7" breadboard. The pre-concentration process is controlled using automation scripts and software. An optical window allows a Raman spectrometer to directly monitor the pre-concentration of amino acids in a filter/column loaded with of a strong cation exchange resin. Initial samples to demonstrate EAAS simulate the conditions of Don Juan Pond, one of the coldest and saltiest bodies of liquid water on Earth, located in the Wright Valley of Antarctica. This EAAS development is an important step toward a new type of astrobiology science instrument that is capable of operating on a spacecraft in flight or in orbit.

  2. Passive sampling of selected pesticides in aquatic environment using polar organic chemical integrative samplers.

    Science.gov (United States)

    Thomatou, Alphanna-Akrivi; Zacharias, Ierotheos; Hela, Dimitra; Konstantinou, Ioannis

    2011-08-01

    Polar chemical integrative samplers (POCIS) were examined for their sampling efficiency of 12 pesticides and one metabolite commonly detected in surface waters. Laboratory-based calibration experiments of POCISs were conducted. The determined passive sampling rates were applied for the monitoring of pesticides levels in Lake Amvrakia, Western Greece. Spot sampling was also performed for comparison purposes. Calibration experiments were performed on the basis of static renewal exposure of POCIS under stirred conditions for different time periods of up to 28 days. The analytical procedures were based on the coupling of POCIS and solid phase extraction by Oasis HLB cartridges with gas chromatography-mass spectrometry. The recovery of the target pesticides from the POCIS was generally >79% with relative standard deviation (RSD) monitoring campaign using both passive and spot sampling whereas higher concentrations were measured by spot sampling in most cases. Passive sampling by POCIS provides a useful tool for the monitoring of pesticides in aquatic systems since integrative sampling at rates sufficient for analytical quantitation of ambient levels was observed. Calibration data are in demand for a greater number of compounds in order to extend the use in environmental monitoring.

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

    Science.gov (United States)

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

    2014-01-01

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

  4. Correlation of centroid-based breast size, surface-based breast volume, and asymmetry-score-based breast symmetry in three-dimensional breast shape analysis

    Directory of Open Access Journals (Sweden)

    Henseler, Helga

    2016-06-01

    Full Text Available Objective: The aim of this study was to investigate correlations among the size, volume, and symmetry of the female breast after reconstruction based on previously published data. Methods: The centroid, namely the geometric center of a three-dimensional (3D breast-landmark-based configuration, was used to calculate the size of the breast. The surface data of the 3D breast images were used to measure the volume. Breast symmetry was assessed by the Procrustes analysis method, which is based on the 3D coordinates of the breast landmarks to produce an asymmetry score. The relationship among the three measurements was investigated. For this purpose, the data of 44 patients who underwent unilateral breast reconstruction with an extended latissimus dorsi flap were analyzed. The breast was captured by a validated 3D imaging system using multiple cameras. Four landmarks on each breast and two landmarks marking the midline were used.Results: There was a significant positive correlation between the centroid-based breast size of the unreconstructed breast and the measured asymmetry (p=0.024; correlation coefficient, 0.34. There was also a significant relationship between the surface-based breast volume of the unaffected side and the overall asymmetry score (p<0.001; correlation coefficient, 0.556. An increase in size and especially in volume of the unreconstructed breast correlated positively with an increase in breast asymmetry in a linear relationship.Conclusions: In breast shape analysis, the use of more detailed surface-based data should be preferred to centroid-based size data. As the breast size increases, the latissimus dorsi flap for unilateral breast reconstruction increasingly falls short in terms of matching the healthy breast in a linear relationship. Other reconstructive options should be considered for larger breasts. Generally plastic surgeons should view the two breasts as a single unit when assessing breast aesthetics and not view each

  5. Influence of wind-speed on short-duration NO2 measurements using Palmes and Ogawa passive diffusion samplers

    Science.gov (United States)

    Masey, Nicola; Gillespie, Jonathan; Heal, Mathew R.; Hamilton, Scott; Beverland, Iain J.

    2017-07-01

    We assessed the precision and accuracy of nitrogen dioxide (NO2) concentrations over 2-day, 3-day and 7-day exposure periods measured with the following types of passive diffusion samplers: standard (open) Palmes tubes; standard Ogawa samplers with commercially-prepared Ogawa absorbent pads (Ogawa[S]); and modified Ogawa samplers with absorbent-impregnated stainless steel meshes normally used in Palmes tubes (Ogawa[P]). We deployed these passive samplers close to the inlet of a chemiluminescence NO2 analyser at an urban background site in Glasgow, UK over 32 discrete measurement periods. Duplicate relative standard deviation was associated with wind-speed (P associated with wind-speed resulting in a high correlation between estimated concentrations and observed analyser concentrations. The use of Palmes meshes in Ogawa[P] samplers reduced the cost of sampler preparation and removed uncertainty associated with the unknown manufacturing process for the commercially-prepared collection pads.

  6. Synthesis of Macro-Mesostructuredγ-Al2O3 with Large Pore Volume and High Surface Area by a Facile Secondary Reforming Method

    Institute of Scientific and Technical Information of China (English)

    Meng Xiuhong; Duan Linhai; Xie Xiaohua; Wang Qiang; Wang Haiyan

    2014-01-01

    Through improving the aging process during synthesis of the support,γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction tem-perature, the ifrst aging temperature and the second aging temperature, were investigated. The textural properties ofγ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetry (TG). The experimental results indicated that AACH and amorphous AlOOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesizedγ-Al2O3 materials featured meso/macroporosity, large pore volume (2.175 cm3/g), high surface area (237.8 m2/g), and low bulk density (0.284 g/mL).

  7. Comparison and use of 3D scanners to improve the quantification of medical images (surface structures and volumes) during follow up of clinical (surgical) procedures

    Science.gov (United States)

    Tokkari, Niki; Verdaasdonk, Rudolf M.; Liberton, Niels; Wolff, Jan; den Heijer, Martin; van der Veen, Albert; Klaessens, John H.

    2017-02-01

    It is difficult to obtain quantitative measurements as to surface areas and volumes from standard photos of the body parts of patients which is highly desirable for objective follow up of treatments in e.g. dermatology. plastic, aesthetic and reconstructive surgery. Recently, 3-D scanners have become available to provide quantification. Phantoms (3-D printed hand, nose and ear, colored bread sculpture) were developed to compare a range from low-cost (Sense), medium (HP Sprout) to high end (Artec Spider, Vectra M3) scanners using different 3D imaging technologies, as to resolution, working range, surface color representation, user friendliness. The 3D scans files (STL, OBJ) were processed with Artec studio and GOM software as to deviation compared to the high resolution Artec Spider scanner taken as `golden' standard. The HP Spout, which uses a fringe projection, proved to be nearly as good as the Artec, however, needs to be converted for clinical use. Photogrammetry as used by the Vectra M3 scanner is limited to provide sufficient data points for accurate surface mapping however provides good color/structure representation. The low performance of the Sense is not recommended for clinical use. The Artec scanner was successfully used to measure the structure/volume changes in the face after hormone treatment in transgender patients. 3D scanners can greatly improve quantitative measurements of surfaces and volumes as objective follow up in clinical studies performed by various clinical specialisms (dermatology, aesthetic and reconstructive surgery). New scanning technologies, like fringe projection, are promising for development of low-cost, high precision scanners.

  8. Volume-surface barrier discharge in dried air in three-electrode system fed by impulse high voltage with nanosecond rise time

    Science.gov (United States)

    Malashin, Maxim; Rebrov, Igor; Nebogatkin, Sergey; Sokolova, Marina; Nikitin, Alexey; Voevodin, Vadim; Krivov, Sergey

    2016-08-01

    Results of experimental investigation of a volume-surface barrier discharge in a three-electrode system under periodic impulse voltage applied to the surface discharge (SD) electrodes and a d.c. potential applied to an additional third electrode are presented. It is shown that there is a strong influence of polarity and amplitude of the d.c. potential on the direct current "extracted" out of the surface discharge plasma layer by electric field of the third electrode. The amount of charged positive species that constitute the "extracted" current prevails under positive impulse voltage for low values of the negative d.c. potential of the third electrode. The amount of negative species prevails with higher values of the positive d.c. positive of the third electrode. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  9. Polar organic chemical integrative sampler (POCIS) uptake rates for 17 polar pesticides and degradation products: laboratory calibration

    OpenAIRE

    Ibrahim, Imtiaz; Togola, Anne; Gonzalez, Catherine

    2013-01-01

    International audience; Polar organic chemical integrative samplers (POCIS) are useful for monitoring a wide range of chemicals, including polar pesticides, in water bodies. However, few calibration data are available, which limits the use of these samplers for time-weighted average concentration measurements in an aquatic medium. This work deals with the laboratory calibration of the pharmaceutical configuration of a polar organic chemical integrative sampler (pharm-POCIS) for calculating th...

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

    Science.gov (United States)

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

    2012-12-01

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

  11. 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.

  12. Surface wave techniques for the evaluation of concrete structures, In : Non-destructive evaluation of reinforced concrete structures, Volume 2

    OpenAIRE

    Popovics, John; Abraham, Odile

    2010-01-01

    This chapter describes non-destructive test methods based on surface guided mechanical waves for application to concrete. After a summary of the history of development of the methods, surface wave propagation in homogenous and layered media is reviewed, where analytical and numerical modelling efforts are described. Then specific time domain and frequency domain surface wave methods are introduced, including the SASW and MASW methods. The needed equipment are described and finally successful ...

  13. Development of polar organic integrative samplers for analysis of pharmaceuticals in aquatic systems.

    Science.gov (United States)

    Togola, Anne; Budzinski, Hélène

    2007-09-01

    Integrative passive sampling is a new approach developed for environmental monitoring. Nowadays, the evaluations of pollution level are obtained by important sampling campaigns using spot samplings that give a snapshot of the aquatic system contamination state. An alternative way is to achieve a time weighted average concentration using passive samplers. The use of polar organic chemical integrative sampling (POCIS) has been recently documented for the detection of pharmaceuticals in the environment (Alvarez, D.; Petty, J. D.; Huckins, J. N.; Jones-Lepp, T. L.; Getting, D. T.; Goddard, J. P.; Manahan, S. E. Environ. Toxicol. Chem. 2004, 23, 1640-1648 (ref 1). Jones-Lepp, T. L.; Alvarez, D.; Petty, J. D.; Huckins, J. Arch. Environ. Contam. Toxicol. 2004, 47, 427-739 (ref 2). Petty, J. D.; Huckins, J. N.; Alvarez, D.; Brumbaugh, W. G.; Cranor, W. L.; Gale, R. W.; Rastall, A. C.; Jones-Lepp, T. L.; Leiker, T. J.; Rostad, C. E.; Furlong, E. T. Chemosphere 2004, 54, 695-705 (ref 3)). There is a need for laboratory data to extend the use of this type of tool to new compounds. The aim of this study was to determine the sampling rates (Rs; expressed as effective volumes of water extracted daily) of POCIS devices for 14 pharmaceuticals in several conditions of temperature, salinity, and analyte concentration. These values are influenced by significant changes in water temperature and salinity. Overall, POCIS Rs values were independent from aqueous concentrations. After laboratory experiments, an environmental field study has been performed, implementing POCIS devices in the Seine estuary (North Atlantic coast of France) and testing the qualitative and quantitative application of POCIS devices on the contaminated system. The suitability of the devices for monitoring multiple media under a wide range of environmental conditions has also been discussed. The uniformity or reproducibility of the sampling matrix and, on the other hand, the ability to detect compounds at low

  14. Some molecular/crystalline factors that affect the sensitivities of energetic materials: molecular surface electrostatic potentials, lattice free space and maximum heat of detonation per unit volume.

    Science.gov (United States)

    Politzer, Peter; Murray, Jane S

    2015-02-01

    We discuss three molecular/crystalline properties that we believe to be among the factors that influence the impact/shock sensitivities of energetic materials (i.e., their vulnerabilities to unintended detonation due to impact or shock). These properties are (a) the anomalously strong positive electrostatic potentials in the central regions of their molecular surfaces, (b) the free space per molecule in their crystal lattices, and (c) their maximum heats of detonation per unit volume. Overall, sensitivity tends to become greater as these properties increase; however these are general trends, not correlations. Nitramines are exceptions in that their sensitivities show little or no variation with free space in the lattice and heat of detonation per unit volume. We outline some of the events involved in detonation initiation and show how the three properties are related to different ones of these events.

  15. Is the Surface Potential Integral of a Dipole in a Volume Conductor Always Zero? A Cloud Over the Average Reference of EEG and ERP.

    Science.gov (United States)

    Yao, Dezhong

    2017-02-14

    Currently, average reference is one of the most widely adopted references in EEG and ERP studies. The theoretical assumption is the surface potential integral of a volume conductor being zero, thus the average of scalp potential recordings might be an approximation of the theoretically desired zero reference. However, such a zero integral assumption has been proved only for a spherical surface. In this short communication, three counter-examples are given to show that the potential integral over the surface of a dipole in a volume conductor may not be zero. It depends on the shape of the conductor and the orientation of the dipole. This fact on one side means that average reference is not a theoretical 'gold standard' reference, and on the other side reminds us that the practical accuracy of average reference is not only determined by the well-known electrode array density and its coverage but also intrinsically by the head shape. It means that reference selection still is a fundamental problem to be fixed in various EEG and ERP studies.

  16. Tight Bounds for Lp Samplers, Finding Duplicates in Streams, and Related Problems

    CERN Document Server

    Jowhari, Hossein; Tardos, Gábor

    2010-01-01

    In this paper, we present near-optimal space bounds for Lp-samplers. Given a stream of updates (additions and subtraction) to the coordinates of an underlying vector x \\in R^n, a perfect Lp sampler outputs the i-th coordinate with probability |x_i|^p/||x||_p^p. In SODA 2010, Monemizadeh and Woodruff showed polylog space upper bounds for approximate Lp-samplers and demonstrated various applications of them. Very recently, Andoni, Krauthgamer and Onak improved the upper bounds and gave a O(\\epsilon^{-p} log^3 n) space \\epsilon relative error and constant failure rate Lp-sampler for p \\in [1,2]. In this work, we give another such algorithm requiring only O(\\epsilon^{-p} log^2 n) space for p \\in (1,2). For p \\in (0,1), our space bound is O(\\epsilon^{-1} log^2 n), while for the $p=1$ case we have an O(log(1/\\epsilon)\\epsilon^{-1} log^2 n) space algorithm. We also give a O(log^2 n) bits zero relative error L0-sampler, improving the O(log^3 n) bits algorithm due to Frahling, Indyk and Sohler. As an application of ou...

  17. Polar organic chemical integrative samplers for pesticides monitoring: impacts of field exposure conditions.

    Science.gov (United States)

    Lissalde, Sophie; Mazzella, Nicolas; Mazellier, Patrick

    2014-08-01

    This study focuses on how Polar Organic Chemical Integrative Samplers (POCIS) work in real environmental conditions. A selection of 23 polar pesticides and 8 metabolites were investigated by exposure of triplicates of integrative samplers in two rivers in France for successive 14-day periods. The pesticides and metabolites were trapped not only in Oasis HLB sorbent but also in the polyethersulfone (PES) membrane of the POCIS. The distribution of pesticides depended on the molecular structure. The use of the Performance Reference Compound (PRC) is also discussed here. The impact of some environmental parameters and exposure setup on the transfer of pesticides in POCIS sorbent was studied: river flow rate, biofouling on membranes, sampler holding design and position in the stream. Results show a significant impact of river flow velocity on PRC desorption, especially for values higher than 4 cm·s(-1). Some fouling was observed on the PES membrane which could potentially have an impact on molecule accumulation in the POCIS. Finally, the positioning of the sampler in the river did not have significant effects on pesticide accumulation, when perpendicular exposures were used (sampler positioning in front of the water flow). The POCIS with PRC correction seems to be a suitable tool for estimating time-weighted average (TWA) concentrations, for all the molecules except for one of the nine pesticides analyzed in these two French rivers.

  18. Northward advection of Atlantic water in the eastern Nordic Seas over the last 3000 yr: a coccolith investigation of volume transport and surface water changes

    Directory of Open Access Journals (Sweden)

    C. V. Dylmer

    2013-03-01

    Full Text Available Three marine sediment cores distributed along the Norwegian (MD95-2011, Barents Sea (JM09-KA11-GC, and Svalbard (HH11-134-BC continental margins have been investigated in order to reconstruct changes in the poleward flow of Atlantic Waters (AW and in the nature of upper surface water masses within the eastern Nordic Seas over the last 3000 yr. These reconstructions are based on a limited set of coccolith proxies: the abundance ratio between Emiliania huxleyi and Coccolithus pelagicus, an index of Atlantic vs. Polar-Arctic surface water masses; and Gephyrocapsa muellerae, a drifted coccolith species from the temperate North Atlantic, whose abundance changes are related to variations in the volume transport of the North Atlantic Current and its northernmost extension (the West Spitsbergen Current – WSC off western Svalbard. The entire investigated area, from 66 to 77° N, was affected by an overall increase in volume flow of AW from 3000 cal yr BP to Present. The long-term modulation of westerlies strength and location which are essentially driven by the dominant mode of the North Atlantic Oscillation (NAO, is thought to explain the observed dynamics of poleward AW flow. The same mechanism also reconciles the recorded opposite zonal shifts in the location of the Arctic Front between the area off western Norway and the Barents Sea-eastern Fram Strait region. The Little Ice Age was governed by deteriorating conditions, with Arctic/Polar waters dominating in the surface off western Svalbard and western Barents Sea, possibly associated with both severe sea-ice conditions and a strongly reduced AW volume flow. A sudden short pulse of resumed high WSC flow interrupted this cold spell in eastern Fram Strait from 330 to 410 cal yr BP, with a a magnitude only surpassed by the one which characterizes the Modern Period. Our dataset not only confirms the high amplitude warming of surface waters at the turn of the 19th century off western Svalbard, it also

  19. A new numerical framework to simulate viscoelastic free-surface flows with the finite-volume method

    DEFF Research Database (Denmark)

    Comminal, Raphaël; Spangenberg, Jon; Hattel, Jesper Henri

    A new method for the simulation of 2D viscoelastic flow is presented. Numerical stability is obtained by the logarithmic-conformation change of variable, and a fully-implicit pure-streamfunction flow formulation, without use of any artificial diffusion. As opposed to other simulation results, our...... calculations predict a hydrodynamic instability in the 4:1 contraction geometry at a Weissenberg number of order 4. This new result is in qualitative agreement with the prediction of a non-linear subcritical elastic instability in Poiseuille flow. Our viscoelastic flow solver is coupled with a volume...

  20. A new numerical framework to simulate viscoelastic free-surface flows with the finite-volume method

    DEFF Research Database (Denmark)

    Comminal, Raphaël; Spangenberg, Jon; Hattel, Jesper Henri

    2015-01-01

    A new method for the simulation of 2D viscoelastic flow is presented. Numerical stability is obtained by the logarithmic-conformation change of variable, and a fully-implicit pure-streamfunction flow formulation, without use of any artificial diffusion. As opposed to other simulation results, our...... calculations predict a hydrodynamic instability in the 4:1 contraction geometry at a Weissenberg number of order 4. This new result is in qualitative agreement with the prediction of a non-linear subcritical elastic instability in Poiseuille flow. Our viscoelastic flow solver is coupled with a volume...

  1. From surface to volume plasmons in hyperbolic metamaterials: General existence conditions for bulk high-k waves in metal-dielectric and graphene-dielectric multilayers

    CERN Document Server

    Zhukovsky, Sergei V; Sipe, J E; Lavrinenko, Andrei V

    2014-01-01

    We theoretically investigate general existence conditions for broadband bulk large-wavevector (high-k) propagating waves (such as volume plasmon polaritons in hyperbolic metamaterials) in subwavelength periodic multilayer structures. Describing the elementary excitation in the unit cell of the structure by a generalized resonance pole of a reflection coefficient, and using Bloch's theorem, we derive analytical expressions for the band of large-wavevector propagating solutions. We apply our formalism to determine the high-k band existence in two important cases: the well-known metal-dielectric, and recently introduced graphene-dielectric stacks. We confirm that short-range surface plasmons in thin metal layers can give rise to hyperbolic metamaterial properties, and demonstrate that long-range surface plasmons cannot. We also show that graphene-dielectric multilayers tend to support high-k waves and explore the range of parameters for which this is possible, confirming the prospects of using graphene for mater...

  2. Design of an air sampler for a small unmanned aerial vehicle.

    Science.gov (United States)

    Peräjärvi, K; Lehtinen, J; Pöllänen, R; Toivonen, H

    2008-01-01

    In the aftermath of a nuclear accident or malevolent act, it is of paramount importance to have the capability to monitor airborne radioactive substances by collecting air samples. For potentially dangerous missions, the Radiation and Nuclear Safety Authority of Finland (STUK) has developed an air sampler to be used on a small unmanned aerial vehicle. When a Petrianov or Fluoropore filter is used in the sampler and the air velocity is 71 km h(-1), the air flow rate through the filter is 0.73 m(3) h(-1) or 0.23 m(3) h(-1), respectively. The present article introduces the developed air sampler using fluid dynamic simulations and wind tunnel data. The operation of the system was validated by collecting airborne radioactive aerosols from air.

  3. Chaotic motif sampler: detecting motifs from biological sequences by using chaotic neurodynamics

    Science.gov (United States)

    Matsuura, Takafumi; Ikeguchi, Tohru

    Identification of a region in biological sequences, motif extraction problem (MEP) is solved in bioinformatics. However, the MEP is an NP-hard problem. Therefore, it is almost impossible to obtain an optimal solution within a reasonable time frame. To find near optimal solutions for NP-hard combinatorial optimization problems such as traveling salesman problems, quadratic assignment problems, and vehicle routing problems, chaotic search, which is one of the deterministic approaches, has been proposed and exhibits better performance than stochastic approaches. In this paper, we propose a new alignment method that employs chaotic dynamics to solve the MEPs. It is called the Chaotic Motif Sampler. We show that the performance of the Chaotic Motif Sampler is considerably better than that of the conventional methods such as the Gibbs Site Sampler and the Neighborhood Optimization for Multiple Alignment Discovery.

  4. Gaseous Products of Incense Coil Combustion Extracted by Passive Solid Phase Microextraction Samplers

    Directory of Open Access Journals (Sweden)

    Wen-Hsi Cheng

    2015-06-01

    Full Text Available Burning incense indoors is a common behavior in Southeast Asia. In this investigation, needle trap samplers (NTS, a novel, green analytical technology is used for sampling gaseous combustion by-products from sandalwood incense coils. To extract indoor volatile organic compounds (VOCs, two NTS are prepared, one using 60–80 mesh and the other using 100–120 mesh divinylbenzene (DVB particles packed in 22-gauge stainless steel needles. This work compares extraction efficiency of an NTS and that of a commercially available 100 μm polydimethylsiloxane solid phase microextration (PDMS-SPME fiber sampler. Experimental results indicated that the 100–120 mesh DVB-NTS performed best among all samplers during a 1 h sampling period. The main extracted compounds were toluene, ethylbenzene, propane, chloromethane, 1,3-butadiene, methanol and dichloromethane. The potential use of small badge-sized or pen-sized NTS for the indoor atmosphere and occupational hygiene applications is addressed.

  5. Comparison of Pipelle sampler with conventional dilatation and curettage (D&C) for Chinese endometrial biopsy.

    Science.gov (United States)

    Liu, H; Wang, F-L; Zhao, Y-M; Yao, Y-Q; Li, Y-L

    2015-01-01

    The aim of this study is to investigate the accuracy and adequacy of the Pipelle endometrial sampler for endometrial biopsy as compared with those of conventional dilatation and curettage (D&C). A total of 245 patients subject to endometrial biopsy were included in this study. We have shown that the failure rates with D&C and Pipelle were 7.75% and 8.98%, respectively, without statistical difference. Additionally, the obtained specimen quality and accurate diagnosis of various diseases using the two methods had no significant statistical differences. Furthermore, patients experienced less pain when Pipelle sampler was used than D&C. Therefore, Pipelle sampler is effective in obtaining adequate endometrial tissue for histodiagnosis, and is applicable in most of the cases for Chinese endometrial biopsy.

  6. Accumulation of polycyclic aromatic hydrocarbons by lichen transplants: Comparison with gas-phase passive air samplers.

    Science.gov (United States)

    Loppi, S; Pozo, K; Estellano, V H; Corsolini, S; Sardella, G; Paoli, L

    2015-09-01

    This study compared the accumulation of 16 polycyclic aromatic hydrocarbons (PAHs) in samples of the lichen Evernia prunastri exposed for 3 months in and around an industrial area of S Italy with that in co-located passive gas-phase air samplers. The results showed a strong linear correlations (R=0.96, P<0.05) between total PAHs in lichens and in passive samplers, clearly indicating that lichen transplants may provide direct quantitative information on the atmospheric load by total PAHs, allowing translation of lichen values into atmospheric concentrations. To the best of our knowledge this is the first study reporting such a correlation with gas-phase passive air samplers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. 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.

  8. 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.

  9. 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.

  10. Mathematical modelling of dust samplers and application of the method to the gravimetric dust sampler RESPICON; Mathematische Modellierung von Staubmessgeraeten und Anwendung der Methode auf das gravimetrische Staubmessgeraet RESPICON

    Energy Technology Data Exchange (ETDEWEB)

    Armbruster, L. [Deutsche Montan Technologie GmbH, Essen (Germany). Gas and Fire Div.

    2004-07-01

    The evaluation and assessment of the fractionating particle sampler RESPICON due to the European test standard prEN 13205 has been continued by mathematical modelling of the candidate sampler and its response to different aerosols, characterized by the mean aerodynamic particle size (MMAD) and standard deviation (GSD). The three health related size fractions are sampled by the candidate sampler within the limits given by the standard, but correction factors for each fraction have to be taken into account. This result stands only for the use of the candidate as affixed point sampler. But due to the regulations in the standard it can be used as a personal sampler for windspeeds up to 2/ms. The investigations also have shown some disadvantages of the test standard itself, these should be eliminated in the future. (orig.)

  11. Floating sample-collection platform with stage-activated automatic water sampler for streams with large variation in stage

    Science.gov (United States)

    Tarte, Stephen R.; Schmidt, A.R.; Sullivan, Daniel J.

    1992-01-01

    A floating sample-collection platform is described for stream sites where the vertical or horizontal distance between the stream-sampling point and a safe location for the sampler exceed the suction head of the sampler. The platform allows continuous water sampling over the entire storm-runoff hydrogrpah. The platform was developed for a site in southern Illinois.

  12. Relative efficiencies of the Burkard 7-Day, Rotorod and Burkard Personal Samplers for Poaceae and Urticaceae pollen under field conditions.

    Science.gov (United States)

    Peel, Robert G; Kennedy, Roy; Smith, Matt; Hertel, Ole

    2014-01-01

    In aerobiological studies it is often necessary to compare concentration data recorded with different models of sampling instrument. Sampler efficiency typically varies from device to device, and depends on the target aerosol and local atmospheric conditions. To account for these differences inter-sampler correction factors may be applied, however for many pollen samplers and pollen taxa such correction factors do not exist and cannot be derived from existing published work. In this study, the relative efficiencies of the Burkard 7-Day Recording Volumetric Spore Trap, the Sampling Technologies Rotorod Model 20, and the Burkard Personal Volumetric Air Sampler were evaluated for Urticaceae and Poaceae pollen under field conditions. The influence of wind speed and relative humidity on these efficiency relationships was also assessed. Data for the two pollen taxa were collected during 2010 and 2011-2012, respectively. The three devices were found to record significantly different concentrations for both pollen taxa, with the exception of the 7-Day and Rotorod samplers for Poaceae pollen. Under the range of conditions present during the study, wind speed was found to only have a significant impact on inter-sampler relationships involving the vertically-orientated Burkard Personal sampler, while no interaction between relative efficiency and relative humidity was observed. Data collected with the three models of sampler should only be compared once the appropriate correction has been made, with wind speed taken into account where appropriate.

  13. Comparison Between Light Scattering and Gravimetric samplers for PM10 mass concentration in Poultry and pig houses

    NARCIS (Netherlands)

    Cambra-Lopez, M.; Winkel, A.; Mosquera Losada, J.; Ogink, N.W.M.; Aarnink, A.J.A.

    2015-01-01

    The objective of this study was to compare co-located real-time light scattering devices and equivalent gravimetric samplers in poultry and pig houses for PM10 mass concentration, and to develop animal-specific calibration factors for light scattering samplers. These results will contribute to evalu

  14. Fused silica capillaries with two segments of different internal diameters and inner surface roughnesses prepared by etching with supercritical water and used for volume coupling electrophoresis.

    Science.gov (United States)

    Horká, Marie; Karásek, Pavel; Roth, Michal; Šlais, Karel

    2017-02-22

    In this work, single-piece fused silica capillaries with two different internal diameter segments featuring different inner surface roughness were prepared by new etching technology with supercritical water and used for volume coupling electrophoresis. The concept of separation and online pre-concentration of analytes in high conductivity matrix is based on the online large-volume sample pre-concentration by the combination of transient isotachophoretic stacking and sweeping of charged proteins in micellar electrokinetic chromatography using non-ionogenic surfactant. The modified surface roughness step helped to the significant narrowing of the zones of examined analytes. The sweeping and separating steps were accomplished simultaneously by the use of phosphate buffer (pH 7) containing ethanol, non-ionogenic surfactant Brij 35, and polyethylene glycol (PEG 10000) after sample injection. Sample solution of a large volume (maximum 3.7 μL) dissolved in physiological saline solution was injected into the wider end of capillary with inlet inner diameter from 150, 185 or 218 μm. The calibration plots were linear (R(2) ∼ 0.9993) over a 0.060-1 μg/mL range for the proteins used, albumin and cytochrome c. The peak area RSDs from at least 20 independent measuremens were below 3.2%. This online pre-concentration technique produced a more than 196-fold increase in sensitivity, and it can be applied for detection of, e.g. the presence of albumin in urine (0.060 μg/mL).

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

    Science.gov (United States)

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

    2005-08-01

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

  16. Approximate reconstruction of bandlimited functions for the integrate and fire sampler

    CERN Document Server

    Feichtinger, Hans G; Romero, José Luis; Alvarado, Alexander Singh; Velasco, Gino Angelo

    2009-01-01

    In this paper we study the reconstruction of a bandlimited signal from samples generated by the integrate and fire model. This sampler allows us to trade complexity in the reconstruction algorithms for simple hardware implementations, and is specially convenient in situations where the sampling device is limited in terms of power, area and bandwidth. Although perfect reconstruction for this sampler is impossible, we give a general approximate reconstruction procedure and bound the corresponding error. We also show the performance of the proposed algorithm through numerical simulations.

  17. Existence and stabilizability of steady-state for semilinear pulse-width sampler controlled system

    Directory of Open Access Journals (Sweden)

    JinRong Wang

    2011-01-01

    Full Text Available In this paper, we study the steady-state of a semilinear pulse-width sampler controlled system on infinite dimensional spaces. Firstly, by virtue of Schauder's fixed point theorem, the existence of periodic solutions is given. Secondly, utilizing a generalized Gronwall inequality given by us and the Banach fixed point theorem, the existence and stabilizability of a steady-state for the semilinear control system with pulse-width sampler is also obtained. At last, an example is given for demonstration.

  18. Reliability of a BTEX radial diffusive sampler for thermal desorption: field measurements

    Science.gov (United States)

    Bruno, P.; Caputi, M.; Caselli, M.; de Gennaro, G.; de Rienzo, M.

    Radiello ®, a radial symmetry diffusive sampler, has been evaluated for its potential for ambient air quality monitoring, in particular for benzene, toluene, ethyl benzene, p-xylene, m-xylene, o-xylene (BTEX) measurements. BTEX were first sampled onto adsorbing cartridges before analyses were performed by thermal desorption and GC-MS. Tests were carried out to determine blank values and any storage effects. The results of an investigation into repeatability of the Radiello ® sampler and the influence of sampling time under field conditions are reported. Inter-comparison with automatic instruments is also illustrated.

  19. Investigation of a New Electrostatic Sampler for Concentrating Biological and Non-Biological Aerosol Particles

    OpenAIRE

    Roux, Jean-Maxime; Kaspari, Oliver; Heinrich, Renate; Hanschmann, Nicole; Grunow, Roland

    2013-01-01

    The detection of airborne pathogens is becoming a subject of great concern in modern day society. Recent studies have shown that electrostatic samplers are suitable for collecting microorganisms as well as preserving their viability. In most of these studies, flow rates were lower than 12.5 L/min or required a concentration stage to increase the flow rate to 100 L/min. In the present study, a single stage electrostatic sampler was developed for an efficient collection of microorganisms at 100...

  20. A sampler for quantifying the vertical distribution of macroinvertebrates in shallow wetlands

    Science.gov (United States)

    MacKay, J.; Euliss, N.H.

    1993-01-01

    A sampler for quantifying the vertical distribution of aquatic macroinvertebrates in wetlands is described. This device will facilitate quantitative sampling of macroinvertebrates in waterfowl ecology and related studies. Because it simultaneously collects benthic and pelagic invertebrates the sampler reduces bias associated with sampling macroinvertebrates that occupy the benthic-pelagic interface of wetlands. The sampling device also separates benthic and pelagic macroinvertebrates into separate vertical profiles to facilitate studies of distribution patterns or the influence of chemical and physical gradients on invertebrate vertical distribution.

  1. Multiple tube sampler for benthic and pelagic invertebrates in shallow wetlands

    Science.gov (United States)

    Euliss, N.H.; Swanson, G.A.; MacKay, J.

    1992-01-01

    Sampling devices that minimize bias and function in aquatic habitats used by waterfowl are needed. We devised a multiple tube sampling device for quantitative sampling of small (< 3 cm) aquatic invertebrates in wetlands. The sampler reduced bias associated with sampling macroinvertebrates that utilize the benthic-pelagic interface because it simultaneously collects benthic and water column invertebrates. The sampler was statistically superior to other sampling devices because each sampling effort provided 4 subsamples and a within-sample variance that could be estimated. The device also was durable and reasonably inexpensive to construct.

  2. Selective bibliography of surface coal mining and reclamation literature. Volume 1. Eastern coal province. [More than 1300 references

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, N. E.; Sobek, A. A.; Streib, D. L.

    1977-11-01

    This bibliography has been compiled for use by researchers, students, and other groups who need a reference source of published literature related to surface coal mining and reclamation in the Eastern Coal Province. This bibliography contains more than 1300 references including government reports, journal articles, symposium proceedings, industrial reports, workshop proceedings, theses, and bibliographices. A simple format was used to categorize citations.

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    Ilaria Negri

    Full Text Available 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.

  5. Analysis of passive-sampler monitored atmospheric ammonia at 74 sites across southern Ontario, Canada

    Directory of Open Access Journals (Sweden)

    X. H. Yao

    2013-08-01

    Full Text Available Weekly/biweekly concentrations of atmospheric NH3 were collected using passive samplers at 74 sites across southern Ontario, Canada during the period from June 2006 to March 2007 with tens of sites running as early as March 2006. The annual average of NH3 (AAN at all the sites across southwestern Ontario was over 1 µg m–3, a value that was recently proposed as the new critical level for protecting vegetation. High ANN values (3.6–6.1 µg m–3 were observed at eight sites located inside the intensive livestock production zones. The AAN values at the sites across southeastern Ontario were generally less than 1 µg m–3 and the values were less than 0.4 µg m–3 at non-agricultural sites. Regional transport from the southwest region to the southeast region was identified to be the main contributor to the observed NH3 at the southeastern non-agricultural sites. However, different transport mechanisms were proposed in different seasons. The transport of NH3 produced through bi-directional air-surface exchange along air mass trajectories was believed to be the main mechanism in the hot seasons while the transport of NH4NO3 produced at source locations followed by its evaporation at receptor sites was thought to be dominant in the cold seasons. A sharp increase in NH3 concentration was surprisingly observed at 20 out of the 74 sites during the coldest two weeks when ambient temperature was lower than −7 °C, and cannot be explained by known sources or with existing knowledge. Recently developed NH3 emission inventory for southern Ontario was also evaluated with the measurement data and emissions within two small zones were identified to be potentially underestimated.

  6. County-Level Climate Uncertainty for Risk Assessments: Volume 18 Appendix Q - Historical Maximum Near-Surface Wind Speed.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconom ic impacts. The full report is contained in 27 volumes.

  7. County-Level Climate Uncertainty for Risk Assessments: Volume 6 Appendix E - Historical Minimum Near-Surface Air Temperature.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  8. County-Level Climate Uncertainty for Risk Assessments: Volume 4 Appendix C - Historical Maximum Near-Surface Air Temperature.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  9. County-Level Climate Uncertainty for Risk Assessments: Volume 2 Appendix A - Historical Near-Surface Air Temperature.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  10. From the surface to volume: concepts for the next generation of optical-holographic data-storage materials.

    Science.gov (United States)

    Bruder, Friedrich-Karl; Hagen, Rainer; Rölle, Thomas; Weiser, Marc-Stephan; Fäcke, Thomas

    2011-05-09

    Optical data storage has had a major impact on daily life since its introduction to the market in 1982. Compact discs (CDs), digital versatile discs (DVDs), and Blu-ray discs (BDs) are universal data-storage formats with the advantage that the reading and writing of the digital data does not require contact and is therefore wear-free. These formats allow convenient and fast data access, high transfer rates, and electricity-free data storage with low overall archiving costs. The driving force for development in this area is the constant need for increased data-storage capacity and transfer rate. The use of holographic principles for optical data storage is an elegant way to increase the storage capacity and the transfer rate, because by this technique the data can be stored in the volume of the storage material and, moreover, it can be optically processed in parallel. This Review describes the fundamental requirements for holographic data-storage materials and compares the general concepts for the materials used. An overview of the performance of current read-write devices shows how far holographic data storage has already been developed.

  11. 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.

  12. Evaluation of the Snap Sampler for Sampling Ground Water Monitoring Wells for VOCs and Explosives

    Science.gov (United States)

    2007-08-01

    23 Table 4. Results from the holding- time study with...the opposite order. First Holding- Time Study for VOCs The purpose of this study was to determine whether analyte concentra- tions of samples... Study for VOCs The procedure for this study was the same as for the previous holding- time study except that that the Snap Samplers were equilibrated

  13. Variable-suction multicompartment samplers to measure spatiotemporal unsaturated water and solute fluxes

    NARCIS (Netherlands)

    Bloem, E.; Hogervorst, F.A.N.; Rooij, de G.; Stagnitti, F.

    2010-01-01

    To better understand the movement of water and solutes in soils, and the risk of groundwater contamination, we need water and solute flux observations distributed in space and time. We designed a new variable-suction multicompartment percolation sampler that can be buried below an undisturbed soil

  14. Framing the Problem of Identity in Composition and TESOL Studies: A Sampler

    Science.gov (United States)

    Messekher, Hayat

    2011-01-01

    This article looks at how the intricate issue of identity has been addressed and framed in composition and TESOL studies (C&T). It reviews five articles and a book as a sampler to explore identity research in various contexts ranging from the problematic rise of identity in second-language acquisition (SLA) research in 1997, which represented a…

  15. Variable-suction multicompartment samplers to measure spatiotemporal unsaturated water and solute fluxes

    NARCIS (Netherlands)

    Bloem, E.; Hogervorst, F.A.N.; Rooij, de G.; Stagnitti, F.

    2010-01-01

    To better understand the movement of water and solutes in soils, and the risk of groundwater contamination, we need water and solute flux observations distributed in space and time. We designed a new variable-suction multicompartment percolation sampler that can be buried below an undisturbed soil v

  16. 50 CFR 648.11 - At-sea sea sampler/observer coverage.

    Science.gov (United States)

    2010-10-01

    ... or unsafe that the health or safety of the observer or sea sampler, or the safe operation of the.... (h) Observer service provider approval and responsibilities—(1) General. An entity seeking to provide... reports regarding observer conflict of interest or breach of the standards of behavior must be submitted...

  17. 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...

  18. Detection of airborne Campylobacter with three bioaerosol samplers for alarming bacteria transmission in broilers.

    NARCIS (Netherlands)

    Zhao, Y.; Aarnink, A.J.A.; Groot Koerkamp, P.W.G.; Hagenaars, T.H.J.; Katsma, W.E.A.; Jong, de M.C.M.

    2011-01-01

    In an airborne transmission experiment, Campylobacter in the air was sampled by three types of bioaerosol samplers (all-glass impinger AGI-30, Andersen six-stage impactor, and OMNI-3000) in four broiler rooms. In each room, five 14-day- old broilers inoculated with Campylobacter jejuni were kept in

  19. 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,…

  20. 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

  1. 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.

    Residues if various organochlorine pesticides were determined in the water off the central west coast of India using an in situ sampler. Y-BHC and the two cyclodiene compounds, Aldrine and Dieldrin were found to be more consistent than the compounds...

  2. C-Band Airport Surface Communications System Standards Development. Phase II Final Report. Volume 1: Concepts of Use, Initial System Requirements, Architecture, and AeroMACS Design Considerations

    Science.gov (United States)

    Hall, Edward; Isaacs, James; Henriksen, Steve; Zelkin, Natalie

    2011-01-01

    This report is provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-Band and L-Band Communications Standard Development and was based on direction provided by FAA project-level agreements for New ATM Requirements-Future Communications. Task 7 included two subtasks. Subtask 7-1 addressed C-band (5091- to 5150-MHz) airport surface data communications standards development, systems engineering, test bed and prototype development, and tests and demonstrations to establish operational capability for the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2 focused on systems engineering and development support of the L-band digital aeronautical communications system (L-DACS). Subtask 7-1 consisted of two phases. Phase I included development of AeroMACS concepts of use, requirements, architecture, and initial high-level safety risk assessment. Phase II builds on Phase I results and is presented in two volumes. Volume I (this document) is devoted to concepts of use, system requirements, and architecture, including AeroMACS design considerations. Volume II describes an AeroMACS prototype evaluation and presents final AeroMACS recommendations. This report also describes airport categorization and channelization methodologies. The purposes of the airport categorization task were (1) to facilitate initial AeroMACS architecture designs and enable budgetary projections by creating a set of airport categories based on common airport characteristics and design objectives, and (2) to offer high-level guidance to potential AeroMACS technology and policy development sponsors and service providers. A channelization plan methodology was developed because a common global methodology is needed to assure seamless interoperability among diverse AeroMACS services potentially supplied by multiple service providers.

  3. C-Band Airport Surface Communications System Standards Development. Phase II Final Report. Volume 2: Test Bed Performance Evaluation and Final AeroMACS Recommendations

    Science.gov (United States)

    Hall, Edward; Magner, James

    2011-01-01

    This report is provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-Band and L-Band Communications Standard Development and was based on direction provided by FAA project-level agreements for New ATM Requirements-Future Communications. Task 7 included two subtasks. Subtask 7-1 addressed C-band (5091- to 5150-MHz) airport surface data communications standards development, systems engineering, test bed and prototype development, and tests and demonstrations to establish operational capability for the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2 focused on systems engineering and development support of the L-band digital aeronautical communications system (L-DACS). Subtask 7-1 consisted of two phases. Phase I included development of AeroMACS concepts of use, requirements, architecture, and initial high-level safety risk assessment. Phase II builds on Phase I results and is presented in two volumes. Volume I is devoted to concepts of use, system requirements, and architecture, including AeroMACS design considerations. Volume II (this document) describes an AeroMACS prototype evaluation and presents final AeroMACS recommendations. This report also describes airport categorization and channelization methodologies. The purposes of the airport categorization task were (1) to facilitate initial AeroMACS architecture designs and enable budgetary projections by creating a set of airport categories based on common airport characteristics and design objectives, and (2) to offer high-level guidance to potential AeroMACS technology and policy development sponsors and service providers. A channelization plan methodology was developed because a common global methodology is needed to assure seamless interoperability among diverse AeroMACS services potentially supplied by multiple service providers.

  4. Monitoring solute fluxes: Integrating electrical resistivity with multi-compartment sampler techniques

    Science.gov (United States)

    Bloem, Esther; Fernandez, Perrine; French, Helen K.

    2016-04-01

    The impact of agriculture, industry, airport activities on soil and water quality is strongly influenced by soil heterogeneity. To improve risk assessment, monitoring, and treatment strategies, we require a better understanding of the effect of soil heterogeneity on contaminant movement and better methods for monitoring heterogeneous contaminated transport. Sufficient characterization of spatial and temporal distribution of contaminant transport requires measurements of water and solute fluxes at multiple locations with a high temporal resolution. During this presentation, we will show a newly developed instrument, which combines multi-compartment sampling with electrical resistivity measurements, to observe spatial and temporal fluxes of contaminants. Solute monitoring is often limited to observations of resident concentrations, while flux concentrations govern the movement of solutes in soils. Bloem et al. (2010) developed a multi-compartment sampler (MCS) which is capable of measuring fluxes at a high spatial resolution under natural conditions. The sampler is divided into 100 separate compartments of 31 by 31 mm. Flux data can be recorded at a high time resolution (every 5 minutes). Tracer leaching can be monitored by frequently sampling the collected leachate while leaving the sampler buried in situ. To optimize the monitoring of tracer leaching and measure real solute fluxes the multi-compartment sampler has been extended with 121 electrodes. The electrodes are mounted at each corner of each compartment to measure the electrical conductivity above each compartment while water percolates through the compartments. By using different electrode couples, the setup can also be used to image above the multi-compartment sampler. The instrument can be used for detailed studies both in the laboratory and in the field. For laboratory experiments a transparent column is used which fits perfect on top of the MCS. We present a selection of the integrated electrical

  5. Uses of ANSI/HPS N13.12-1999, "Surface and Volume Radioactivity Standards for Clearance" and Comparison with Existing Standards

    Energy Technology Data Exchange (ETDEWEB)

    Stansbury, Paul S.; Strom, Daniel J.

    2001-04-30

    In August of 1999, the American National Standards Institute (ANSI) approved a standard for clearance of materials contaminated with residual levels of radioactivity. "Clearance," as used in the standard, means the movement of material from the control of a regulatory agency to a use or disposition that has no further regulatory controls of any kind. The standard gives derived screening levels (DSLs) in Bq/g and Bq/cm2 for 50 radionuclides. Items or materials with residual surface and volume radioactivity levels below the DSLs can be cleared, that is, managed without regard to their residual radioactivity. Since federal agencies are to use voluntary, industry standards developed by the private sector whenever possible, the standard should play an important role in DOE's regulatory process. The thrust of this report is to explain the standard, make simple observations on its usefulness to DOE, and to explore uses of the standard within DOE facilities beyond the clearance of radioactive materials.

  6. A Simplified Method for Sampling and Analysis of High Volume Surface Water for Organic Contaminants Using XAD-2

    Science.gov (United States)

    Datta, S.; Do, L.V.; Young, T.M.

    2004-01-01

    A simple compressed-gas driven system for field processing and extracting water for subsequent analyses of hydrophobic organic compounds is presented. The pumping device is a pneumatically driven pump and filtration system that can easily clarify at 4L/min. The extraction device uses compressed gas to drive filtered water through two parallel XAD-2 resin columns, at about 200 mL/min. No batteries or inverters are required for water collection or processing. Solvent extractions were performed directly in the XAD-2 glass columns. Final extracts are cleaned-up on Florisil cartridges without fractionation and contaminants analyzed by GC-MS. Method detection limits (MDLs) and recoveries for dissolved organic contaminants, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides are reported along with results of surface water analysis for the San Francisco Bay, CA.

  7. 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 welding operations.

  8. Comparison of five integrative samplers in laboratory for the monitoring of indicator and dioxin-like polychlorinated biphenyls in water.

    Science.gov (United States)

    Jacquet, Romain; Miège, Cécile; Smedes, Foppe; Tixier, Céline; Tronczynski, Jacek; Togola, Anne; Berho, Catherine; Valor, Ignacio; Llorca, Julio; Barillon, Bruno; Marchand, P; Coquery, Marina

    2014-03-01

    This study aimed at evaluating and comparing five integrative samplers for the monitoring of indicator and dioxin-like polychlorinated biphenyls (PCBs) in water: semi-permeable membrane device (SPMD), silicone rubber, low-density polyethylene (LDPE) strip, Chemcatcher and a continuous-flow integrative sampler (CFIS). These samplers were spiked with performance reference compounds (PRCs) and then simultaneously exposed under constant agitation and temperature in a 200 L stainless steel tank for periods ranging from one day to three months. A constant PCB concentration of about 1 ng·L(-1) was achieved by immersing a large amount of silicone rubber sheets ("dosing sheets") spiked with the target PCBs. The uptake of PCBs in the five samplers showed overall good repeatability and their accumulation was linear with time. The samplers SPMD, silicone rubber and LDPE strip were the most promising in terms of achieving low limits of quantification. Time-weighted average (TWA) concentrations of PCBs in water were estimated from uptake of PCBs using the sampling rates calculated from the release of PRCs. Except for Chemcatcher, a good agreement was found between the different samplers and TWA concentrations ranged between 0.4 and 2.8 times the nominal water concentration. Finally, the influence of calculation methods (sampler-water partition coefficients, selected PRCs, models) on final TWA concentrations was studied.

  9. A suspended-particle rosette multi-sampler for discrete biogeochemical sampling in low-particle-density waters

    Energy Technology Data Exchange (ETDEWEB)

    Breier, J. A.; Rauch, C. G.; McCartney, K.; Toner, B. M.; Fakra, S. C.; White, S. N.; German, C. R.

    2010-06-22

    To enable detailed investigations of early stage hydrothermal plume formation and abiotic and biotic plume processes we developed a new oceanographic tool. The Suspended Particulate Rosette sampling system has been designed to collect geochemical and microbial samples from the rising portion of deep-sea hydrothermal plumes. It can be deployed on a remotely operated vehicle for sampling rising plumes, on a wire-deployed water rosette for spatially discrete sampling of non-buoyant hydrothermal plumes, or on a fixed mooring in a hydrothermal vent field for time series sampling. It has performed successfully during both its first mooring deployment at the East Pacific Rise and its first remotely-operated vehicle deployments along the Mid-Atlantic Ridge. It is currently capable of rapidly filtering 24 discrete large-water-volume samples (30-100 L per sample) for suspended particles during a single deployment (e.g. >90 L per sample at 4-7 L per minute through 1 {mu}m pore diameter polycarbonate filters). The Suspended Particulate Rosette sampler has been designed with a long-term goal of seafloor observatory deployments, where it can be used to collect samples in response to tectonic or other events. It is compatible with in situ optical sensors, such as laser Raman or visible reflectance spectroscopy systems, enabling in situ particle analysis immediately after sample collection and before the particles alter or degrade.

  10. A FMM-FFT accelerated hybrid volume surface integral equation solver for electromagnetic analysis of re-entry space vehicles

    KAUST Repository

    Yücel, Abdulkadir C.

    2014-07-01

    Space vehicles that re-enter the atmosphere often experience communication blackout. The blackout occurs when the vehicle becomes engulfed in plasma produced by interactions between the vehicle surface and the atmosphere. The plasma often is concentrated in a relatively thin shell around the vehicle, with higher densities near its nose than rear. A less structured, sometimes turbulent plasma wake often trails the vehicle. The plasma shell severely affects the performance of side-mounted antennas as it alters their characteristics (frequency response, gain patterns, axial ratio, and impedance) away from nominal, free-space values, sometimes entirely shielding the antenna from the outside world. The plasma plume/turbulent wake similarly affect the performance of antennas mounted at the back of the vehicle. The electromagnetic characteristics of the thin plasma shell and plume/turbulent wake heavily depend on the type of re-entry trajectory, the vehicle\\'s speed, angles of attack, and chemical composition, as well as environmental conditions. To analyze the antennas\\' performance during blackout and to design robust communication antennas, efficient and accurate simulation tools for charactering the antennas\\' performance along the trajectory are called for.

  11. From surface to volume plasmons in hyperbolic metamaterials: General existence conditions for bulk high-k waves in metal-dielectric and graphene-dielectric multilayers

    Science.gov (United States)

    Zhukovsky, Sergei V.; Andryieuski, Andrei; Sipe, J. E.; Lavrinenko, Andrei V.

    2014-10-01

    We theoretically investigate general existence conditions for broadband bulk large-wave-vector (high-k) propagating waves (such as volume plasmon polaritons in hyperbolic metamaterials) in subwavelength periodic multilayer structures. Describing the elementary excitation in the unit cell of the structure by a generalized resonance pole of a reflection coefficient and using Bloch's theorem, we derive analytical expressions for the band of large-wave-vector propagating solutions. We apply our formalism to determine the high-k band existence in two important cases: the well-known metal-dielectric and recently introduced graphene-dielectric stacks. We confirm that short-range surface plasmons in thin metal layers can give rise to hyperbolic metamaterial properties and demonstrate that long-range surface plasmons cannot. We also show that graphene-dielectric multilayers tend to support high-k waves and explore the range of parameteres for which this is possible, confirming the prospects of using graphene for materials with hyperbolic dispersion. The approach is applicable to a large variety of structures, such as continuous or structured microwave, terahertz, and optical metamaterials.

  12. Surface area and volume measurements of volcanic ash particles using micro-computed tomography (micro-CT): A comparison with scanning electron microscope (SEM) stereoscopic imaging and geometric considerations

    Science.gov (United States)

    Ersoy, Orkun; Şen, Erdal; Aydar, Erkan; Tatar, İlkan; Çelik, H. Hamdi

    2010-10-01

    Volcanic ash particles are important components of explosive eruptions, and their surface textures are the subject of intense research. Characterization of ash surfaces is crucial for understanding the physics of volcanic plumes, remote sensing measurements of ash and aerosols, interfacial processes, modelling transportation and deposition of tephra and characterizing eruptive styles. A number of different methods have been used over the years to arrive at surface area estimates. The more common methods include estimates based on geometric considerations (geometric surface area) and physisorption of gas molecules on the surface of interest (physical surface area). In this study, micro computed tomography (micro-CT), which is a non-destructive method providing three-dimensional data, enabled the measurement of surface area and volume of individual ash particles. Results were compared with the values obtained from SEM stereoscopic imaging and geometric considerations. Surface area estimates of micro-CT and SEM stereoscopic imaging are similar, with surface area/volume ratios (SA/V) of 0.0368 and 0.0467, respectively. Ash particle surface textures show a large deviation from that of simple geometric forms, and an approximation both to spheres and ellipsoids do not seem adequate for the representation of ash surface. SEM stereoscopic and/or micro-CT imaging are here suggested as good candidate techniques for the characterization of textures on macro-pore regions of ash particles.

  13. Relações da rugosidade superficial do solo com o volume de chuva e com a estabilidade de agregados em água Relations of soil surface roughness with the rainfall volume and water aggregate stability

    Directory of Open Access Journals (Sweden)

    Ildegardis Bertol

    2006-06-01

    -se inversamente com o volume das chuvas naturais. O decaimento máximo da rugosidade ao acaso relacionou-se inversamente com o DMP e com o DMG dos agregados estruturais.Soil surface roughness is, among other factors, affected by soil tillage, cumulative rainfall and aggregate stability in relation to destructive water action. The soil surface roughness of a soil classified as a Haplumbrept was evaluated in an area where a water erosion experiment under natural rainfall has been carried out over the course of 15 years in the South of the Planalto Catarinense, Santa Catarina State, Brazil. The soil microrelief was characterized by the indices: roughness (RR, tortuosity (T and limiting elevation difference (LD and was measured in 2003 in a corn crop, and in 2004 in an oat crop (cumulative rainfall during the experimental periods was 229 and 350 mm, respectively. Moreover, water aggregate stability was evaluated and expressed by the mean weight diameter (DMP and mean geometric diameter (DMG of aggregates between the two crops, in 2004. The studied soil tillage system treatments were: plowing plus disking (PC, chisel plow plus disking (CM, and no-tillage (SD, both under corn and oat crops. One additional treatment used as reference consisted of bare soil tillage with plowing plus disking (SC. The surface roughness was evaluated five times under corn and four times under oat. The first evaluation was carried out immediately after soil tilling and the others every other week. The initial values of the RR, T, and LD indices were high and decreased with increasing rainfall on SC, PC AND CM treatments, while in the SD treatment the afore-mentioned indices were only high for oat and varied very little as the rainfall increased. The reduction in the random RR index was the highest in the BS treatment, while the lowest reduction occurred in the SD treatment. The values of all indices under study were reduced in comparison to that of the original microrelief condition, where the slope effects

  14. 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

  15. Airborne virus sampling: Efficiencies of samplers and their detection limits for infectious bursal disease virus (IBDV

    Directory of Open Access Journals (Sweden)

    Yang Zhao

    2014-09-01

    Full Text Available [b]Introduction[/b]. The airborne transmission of infectious diseases in livestock production is increasingly receiving research attention. Reliable techniques of air sampling are crucial to underpin the findings of such studies. This study evaluated the physical and biological efficiencies and detection limits of four samplers (Andersen 6-stage impactor, all-glass impinger “AGI-30”, OMNI-3000 and MD8 with gelatin filter for collecting aerosols of infectious bursal disease virus (IBDV. [b]Materials and Method[/b]. IBDV aerosols mixed with a physical tracer (uranine were generated in an isolator, and then collected by the bioaerosol samplers. Samplers’ physical and biological efficiencies were derived based on the tracer concentration and the virus/tracer ratio, respectively. Detection limits for the samplers were estimated with the obtained efficiency data. [b]Results.[/b] Physical efficiencies of the AGI-30 (96% and the MD8 (100% were significantly higher than that of the OMNI-3000 (60%. Biological efficiency of the OMNI-3000 (23% was significantly lower than 100% (P < 0.01, indicating inactivation of airborne virus during sampling. The AGI-30, the Andersen impactor and the MD8 did not significantly inactivate virus during sampling. The 2-min detection limits of the samplers on airborne IBDV were 4.1 log[sub]10[/sub] 50% egg infective dose (EID[sub]50[/sub] m [sup]-3[/sup] for the Andersen impactor, 3.3 log[sub]10[/sub] EID50 m [sup]-3[/sup] for the AGI-30, 2.5 log[sub]10[/sub] EID50 m [sup]-3[/sup] for the OMNI-3000, and 2.9 log[sub]10[/sub] EID[sub]50[/sub] m [sup]-3[/sup] for the MD8. The mean half-life of IBDV aerosolized at 20 °C and 70% was 11.9 min. Conclusion. Efficiencies of different samplers vary. Despite its relatively low sampling efficiency, the OMNI-3000 is suitable for use in environments with low viral concentrations because its high flow rate gives a low detection limit. With the 4 samplers investigated, negative air

  16. 30 CFR 74.4 - Specifications of sampler unit.

    Science.gov (United States)

    2010-07-01

    ...: (1) Cyclone. The cyclone shall consist of a cyclone body with removable grit cap and a vortex finder... cyclone body, part No. 28541/4A or 01B11476-01 and vortex finder, part No. 28541/4B. (2) Filter assembly... dissolve or decompose when immersed in ethyl or isopropyl alcohol. The strength and surface...

  17. Development of a flexible dialysis pore water sampler placement system: easy handling and related error sources

    Directory of Open Access Journals (Sweden)

    Stephan Hilgert

    2014-02-01

    Full Text Available Investigations in the context of greenhouse gas production measurements in sub-tropical reservoirs brought up the necessity to survey the in situ pore water gas and ion concentrations at many positions within a relatively short time. As several sediment cores were taken, the interest in analyzing the pore water at the same time and at the same positions forced us to develop a cost- and time saving method for the placement of dialysis pore water samplers (DPS. General prerequisites were the ability to place several DPS per day, within a flexible depth range of up to 40 m and with a low cost budget. To meet these requirements, a DPS placing system (DPSPS was developed, which would allow the precise placement of DPS in water with a depth of up to 40 m and assessing the biases of on-board measurements and possible methodological improvements. The DPSPS was transported to Brazil and tested in a measurement campaign for 10 days. The measurements were carried out during two campaigns in December 2012 and March 2013 in the Capivari Reservoir north-east of Curitiba in the State of Paraná. The system worked properly and several DPS could be placed from a 5 m class aluminum boat. The placement was performed with high accuracy regarding the positioning as well as the penetration depth of the DPS. After the recovery of the DPS, the possible biases during sampling were analyzed. Possible back-diffusion was investigated, taking oxygen concentration as one representative parameter for estimation of the sample behavior. Laboratory as well as field results showed that special care has to be taken to minimize the influence of diffusion processes during post-recovery sampling. The results also suggested that the used membranes are affected by clogging which is likely to influence the diffusion times of various ions and gases. It can be stated that the DPSPS was developed successfully as the demands in terms of handling as well as monitoring efficiency and sample

  18. Large-volume constant-concentration sampling technique coupling with surface-enhanced Raman spectroscopy for rapid on-site gas analysis

    Science.gov (United States)

    Zhang, Zhuomin; Zhan, Yisen; Huang, Yichun; Li, Gongke

    2017-08-01

    In this work, a portable large-volume constant-concentration (LVCC) sampling technique coupling with surface-enhanced Raman spectroscopy (SERS) was developed for the rapid on-site gas analysis based on suitable derivatization methods. LVCC sampling technique mainly consisted of a specially designed sampling cell including the rigid sample container and flexible sampling bag, and an absorption-derivatization module with a portable pump and a gas flowmeter. LVCC sampling technique allowed large, alterable and well-controlled sampling volume, which kept the concentration of gas target in headspace phase constant during the entire sampling process and made the sampling result more representative. Moreover, absorption and derivatization of gas target during LVCC sampling process were efficiently merged in one step using bromine-thiourea and OPA-NH4+ strategy for ethylene and SO2 respectively, which made LVCC sampling technique conveniently adapted to consequent SERS analysis. Finally, a new LVCC sampling-SERS method was developed and successfully applied for rapid analysis of trace ethylene and SO2 from fruits. It was satisfied that trace ethylene and SO2 from real fruit samples could be actually and accurately quantified by this method. The minor concentration fluctuations of ethylene and SO2 during the entire LVCC sampling process were proved to be samples were achieved in range of 95.0-101% and 97.0-104% respectively. It is expected that portable LVCC sampling technique would pave the way for rapid on-site analysis of accurate concentrations of trace gas targets from real samples by SERS.

  19. Large-volume constant-concentration sampling technique coupling with surface-enhanced Raman spectroscopy for rapid on-site gas analysis.

    Science.gov (United States)

    Zhang, Zhuomin; Zhan, Yisen; Huang, Yichun; Li, Gongke

    2017-08-05

    In this work, a portable large-volume constant-concentration (LVCC) sampling technique coupling with surface-enhanced Raman spectroscopy (SERS) was developed for the rapid on-site gas analysis based on suitable derivatization methods. LVCC sampling technique mainly consisted of a specially designed sampling cell including the rigid sample container and flexible sampling bag, and an absorption-derivatization module with a portable pump and a gas flowmeter. LVCC sampling technique allowed large, alterable and well-controlled sampling volume, which kept the concentration of gas target in headspace phase constant during the entire sampling process and made the sampling result more representative. Moreover, absorption and derivatization of gas target during LVCC sampling process were efficiently merged in one step using bromine-thiourea and OPA-NH4(+) strategy for ethylene and SO2 respectively, which made LVCC sampling technique conveniently adapted to consequent SERS analysis. Finally, a new LVCC sampling-SERS method was developed and successfully applied for rapid analysis of trace ethylene and SO2 from fruits. It was satisfied that trace ethylene and SO2 from real fruit samples could be actually and accurately quantified by this method. The minor concentration fluctuations of ethylene and SO2 during the entire LVCC sampling process were proved to be samples were achieved in range of 95.0-101% and 97.0-104% respectively. It is expected that portable LVCC sampling technique would pave the way for rapid on-site analysis of accurate concentrations of trace gas targets from real samples by SERS. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Airway surface liquid volume expansion induces rapid changes in amiloride-sensitive Na+ transport across upper airway epithelium-Implications concerning the resolution of pulmonary edema

    Science.gov (United States)

    Azizi, Fouad; Arredouani, Abdelilah; Mohammad, Ramzi M

    2015-01-01

    During airway inflammation, airway surface liquid volume (ASLV) expansion may result from the movement of plasma proteins and excess liquid into the airway lumen due to extravasation and elevation of subepithelial hydrostatic pressure. We previously demonstrated that elevation of submucosal hydrostatic pressure increases airway epithelium permeability resulting in ASLV expansion by 500 μL cm−2 h−1. Liquid reabsorption by healthy airway epithelium is regulated by active Na+ transport at a rate of 5 μL cm−2 h−1. Thus, during inflammation the airway epithelium may be submerged by a large volume of luminal liquid. Here, we have investigated the mechanism by which ASLV expansion alters active epithelial Na+ transport, and we have characterized the time course of the change. We used primary cultures of tracheal airway epithelium maintained under air interface (basal ASLV, depth is 7 ± 0.5 μm). To mimic airway flooding, ASLV was expanded to a depth of 5 mm. On switching from basal to expanded ASLV conditions, short-circuit current (Isc, a measure of total transepithelial active ion transport) declined by 90% with a half-time (t1/2) of 1 h. 24 h after the switch, there was no significant change in ATP concentration nor in the number of functional sodium pumps as revealed by [3H]-ouabain binding. However, amiloride-sensitive uptake of 22Na+ was reduced by 70% upon ASLV expansion. This process is reversible since after returning cells back to air interface, Isc recovered with a t1/2 of 5–10 h. These results may have important clinical implications concerning the development of Na+ channels activators and resolution of pulmonary edema. PMID:26333829

  1. 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....

  2. Demonstration/Validation of the Snap Sampler Passive Groundwater Sampling Device at the Former McClellan Air Force Base

    Science.gov (United States)

    2011-02-01

    Region 1, 1996), and 3) (where applicable) passive dif- fusion samplers such as the Regenerated Cellulose (RGC or dialysis membrane) sampler...Nielsen (2002), and the ASTM (2003). However, because low-flow sampling draws water most heavily from the most permeable part of the geological...freshwater. The overlying Valley Springs Formation consists of weathered ash from volcanic eruptions, forming low permeability clay with some sand and

  3. 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.

  4. 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.

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

    Institute of Scientific and Technical Information of China (English)

    LI Dehong; ZHUO Weihai; YI Yanling; CHEN Bo; LIU Haikuan

    2008-01-01

    Abstract 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 (C)) 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Arditsoglou, Anastasia [Environmental Pollution Control Laboratory, Chemistry Department, Aristotle University, 54 124 Thessaloniki (Greece); Voutsa, Dimitra [Environmental Pollution Control Laboratory, Chemistry Department, Aristotle University, 54 124 Thessaloniki (Greece)], E-mail: dvoutsa@chem.auth.gr

    2008-11-15

    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.

  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 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...... ratios is consistent with the sorptive capacity of lipids exceeding that of sediment organic carbon from this ecosystem by up to 50-fold. Factors that may contribute to the elevated activity in sediments are discussed, including slower response of sediments than water to reduced emissions, sediment...

  8. DSP based lunar sampling control system for the coiling-type sampler

    Science.gov (United States)

    Ling, Yun; Song, Aiguo; Lu, Wei

    2011-12-01

    The paper develops a control system based on DSP28334 for lunar sampling, and provides the main structure of it. The critical hardware and software design of the system are introduced in detail. The emphasis is placed on the design and realization of the vibration control of the coiling-type sampler in the process of lunar sampling. A control strategy which combines manual-control and local autonomous control is applied for the lunar sampling control. And the sampling mechanism being controlled can realizes multi-motor units working at time-sharing, which reduces the power comsumption and increases the stability of the sampling system greatly. The practical application of the control strategy used for the coiling-type sampler is verified by the finite element analysis. The experiments results show that the system works with low power consumption and high efficiency, and the proposed strategy enables greater depth and better efficiency during sampling.

  9. SEM/EDS of Submicron and Coarse PM Using Modified Passive Aerosol Sampler Substrates

    Science.gov (United States)

    Wagner, J.; Wang, Z.; Willis, B.; Casuccio, G.

    2008-12-01

    Deployment of multiple UNC Passive Aerosol Samplers is an inexpensive and unobtrusive technique for assessing airborne particulate matter (PM) exposure and spatial variability. Computer-controlled SEM/EDS (Scanning Electron Microscopy / Energy-Dispersive X-ray Spectroscopy) is used to measure the deposited particle mass and chemistry. A deposition velocity model is used to obtain ambient PM and elemental size distributions. Previous results have correlated well with active sampler results in environments dominated by coarse mineral dusts. To accurately measure submicron and carbonaceous aerosols, an improved collection substrate is needed. Previous studies used a double-sided carbon adhesive tab, which was ideal for coarse PM but under-detected submicron PM. One promising alternative is polycarbonate (PC) filter substrates. Another is transmission electron microscope (TEM) grids with formvar films mounted over holes drilled in the samplers. Preliminary tests of PC filters and TEM grid substrates, including tests in areas with smoke aerosols, exhibited substantial submicron aerosol and differing elemental size distributions. Detailed qualitative and quantitative evidence shows that the PC filters retained coarse PM well and yielded improved submicron PM imaging. TEM grids yield the best imaging and chemistry of submicron carbonaceous PM, but potentially the poorest retention of coarse PM. PM and elemental size distributions are presented for collocated passive samplers using the three substrate types, in both indoor and outdoor environments. Several methods are proposed to further optimize passive sampling of both submicron and coarse PM. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

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

    Science.gov (United States)

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

    2017-06-01

    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 TiO2 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 TiO2 even for short-term exposure situations.

  11. astroABC : An Approximate Bayesian Computation Sequential Monte Carlo sampler for cosmological parameter estimation

    Science.gov (United States)

    Jennings, E.; Madigan, M.

    2017-04-01

    Given the complexity of modern cosmological parameter inference where we are faced with non-Gaussian data and noise, correlated systematics and multi-probe correlated datasets,the Approximate Bayesian Computation (ABC) method is a promising alternative to traditional Markov Chain Monte Carlo approaches in the case where the Likelihood is intractable or unknown. The ABC method is called ;Likelihood free; as it avoids explicit evaluation of the Likelihood by using a forward model simulation of the data which can include systematics. We introduce astroABC, an open source ABC Sequential Monte Carlo (SMC) sampler for parameter estimation. A key challenge in astrophysics is the efficient use of large multi-probe datasets to constrain high dimensional, possibly correlated parameter spaces. With this in mind astroABC allows for massive parallelization using MPI, a framework that handles spawning of processes across multiple nodes. A key new feature of astroABC is the ability to create MPI groups with different communicators, one for the sampler and several others for the forward model simulation, which speeds up sampling time considerably. For smaller jobs the Python multiprocessing option is also available. Other key features of this new sampler include: a Sequential Monte Carlo sampler; a method for iteratively adapting tolerance levels; local covariance estimate using scikit-learn's KDTree; modules for specifying optimal covariance matrix for a component-wise or multivariate normal perturbation kernel and a weighted covariance metric; restart files output frequently so an interrupted sampling run can be resumed at any iteration; output and restart files are backed up at every iteration; user defined distance metric and simulation methods; a module for specifying heterogeneous parameter priors including non-standard prior PDFs; a module for specifying a constant, linear, log or exponential tolerance level; well-documented examples and sample scripts. This code is hosted

  12. Demonstration/Validation of the Snap Sampler Passive Ground Water Sampling Device

    Science.gov (United States)

    2011-06-01

    direction, although the direction of groundwater movement locally is influenced by water -supply wells and by groundwater extraction and treatment systems...Validation of the Snap Sampler Passive Ground Water Sampling Device June 2011 i COST & PERFORMANCE REPORT Project: ER-200630 TABLE OF CONTENTS...range of analyte types. These included dissolved and total inorganics (including non-metal anions, metalloids , and metals) and four volatile organic

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

    Science.gov (United States)

    2016-11-01

    reconstituted in acetonitrile for HPLC or dichloromethane for GC-MS. Following desorption of organics the passive sampler was dried and the media...and TNT was measured using HPLC with UV detection (Agilent 1100 HPLC with diode array detector). A C18 column (Agilent) was used with a mobile phase...min. In some cases HPLC with mass spectrometry was used to confirm results using a Agilent 1200 HPLC with Series 6400 MS/MS Triple Quadrupole.56 Gas

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

    Science.gov (United States)

    Armendariz, Alfredo; Leith, David

    2003-01-01

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

  15. 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.

  16. 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.

  17. 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.

  18. A Gibbs sampler for Bayesian analysis of site-occupancy data

    Science.gov (United States)

    Dorazio, Robert M.; Rodriguez, Daniel Taylor

    2012-01-01

    1. A Bayesian analysis of site-occupancy data containing covariates of species occurrence and species detection probabilities is usually completed using Markov chain Monte Carlo methods in conjunction with software programs that can implement those methods for any statistical model, not just site-occupancy models. Although these software programs are quite flexible, considerable experience is often required to specify a model and to initialize the Markov chain so that summaries of the posterior distribution can be estimated efficiently and accurately. 2. As an alternative to these programs, we develop a Gibbs sampler for Bayesian analysis of site-occupancy data that include covariates of species occurrence and species detection probabilities. This Gibbs sampler is based on a class of site-occupancy models in which probabilities of species occurrence and detection are specified as probit-regression functions of site- and survey-specific covariate measurements. 3. To illustrate the Gibbs sampler, we analyse site-occupancy data of the blue hawker, Aeshna cyanea (Odonata, Aeshnidae), a common dragonfly species in Switzerland. Our analysis includes a comparison of results based on Bayesian and classical (non-Bayesian) methods of inference. We also provide code (based on the R software program) for conducting Bayesian and classical analyses of site-occupancy data.

  19. Single-breath analysis using a novel simple sampler and capillary electrophoresis with contactless conductometric detection.

    Science.gov (United States)

    Greguš, Michal; Foret, František; Kubáň, Petr

    2015-02-01

    The analysis of ionic content of exhaled breath condensate (EBC) from one single breath by CE with C(4) D is demonstrated for the first time. A miniature sampler made from a 2-mL syringe and an aluminum cooling cylinder for collection of EBC was developed. Various parameters of the sampler that influence its collection efficiency, repeatability, and effect of respiratory patterns were studied in detail. Efficient procedures for the cleanup of the miniature sampler were also developed and resulted in significant improvement of sampling repeatability. Analysis of EBC was performed by CE-C(4) D in a 60 mM MES/l-histidine BGE with 30 μM CTAB and 2 mM 18-crown-6 at pH 6 and excellent repeatability of migration times (RSD < 1.3% (n = 7)) and peak areas (RSD < 7% (n = 7)) of 12 inorganic anions, cations, and organic acids was obtained. It has been shown that the breathing pattern has a significant impact on the concentration of the analytes in the collected EBC. As the ventilatory pattern can be easily controlled during single exhalation, the developed collection system and method provides a highly reproducible and fast way of collecting EBC with applicability in point-of-care diagnostics.

  20. Quantitative method of viral pollution determination for large volume of water using ferric hydroxide gel impregnated on the surface of glassfibre cartridge

    Directory of Open Access Journals (Sweden)

    Akira Homma

    1974-01-01

    Full Text Available Quantitative method of viral pollution determination for large volume of water using ferric hydroxide gel impregnated on the surface of glassfibre cartridge filter. The use of ferric hydroxide gel, impregnated on the surface of glassfibre cartridge filter enable us to recover 62.5% of virus (Poliomylitis type I, Lsc strain exsogeneously added to 400 liters of tap-water. The virus concentrator system consists of four cartridge filters, in which the three first one are clarifiers, where the contaminants are removed physically, without significant virus loss at this stage. The last cartridge filter is impregnated with ferric hydroxide gel, where the virus is adsorbed. After the required volume of water has been processed, the last filter is removed from the system and the viruses are recovered from the gel, using 1 liter of glycine/NaOH buffer, at pH 11. Immediately the eluate is clarified through series of cellulose acetate membranes mounted in a 142mm Millipore filter. For the second step of virus concentration, HC1 1N is added slowly to the eluate to achieve pH 3.5-4. MgC1, is added to give a final concentration of 0.05M and the viruses are readsorbed on a 0.45 , porosity (HA cellulose acetate membrane, mounted in a 90 mm Millipore filter. The viruses are recovered using the same eluent plus 10% of fetal calf serum, to a final volume of 3 ml. In this way, it was possible to concentrate virus from 400 liters of tap-water, into 1 liter in the first stage of virus concentration and just to 3 ml of final volume in a second step. The efficiency, simplicity and low operational cost, provded by the method, make it feasible to study viral pollution of recreational and tap-water sources.Relata-se o emprego de um concentrador portátil, o qual se mostrou capaz de recuperar 62,5% dos vírus (Polio I, amostra Lsc experimentalmente dispersos em 400 litros de água, os quais foram reduzidos a 3 ml. O sistema concentrador de vírus é composto de quatro

  1. Monitoring tylosin and sulfamethazine in a tile-drained agricultural watershed using polar organic chemical integrative sampler (POCIS).

    Science.gov (United States)

    Washington, Maurice T; Moorman, Thomas B; Soupir, Michelle L; Shelley, Mack; Morrow, Amy J

    2017-08-27

    This study evaluated the influence of temporal variation on the occurrence, fate, and transport of tylosin (TYL) and sulfamethazine (SMZ); antibiotics commonly used in swine production. Atrazine (ATZ) was used as a reference analyte to indicate the agricultural origin of the antibiotics. We also assessed the impact of season and hydrology on antibiotic concentrations. A reconnaissance study of the South Fork watershed of the Iowa River (SFIR), was conducted from 2013 to 2015. Tile drain effluent and surface water were monitored using polar organic integrative sampler (POCIS) technology. Approximately 169 animal feeding operations (AFOs) exist in SFIR, with 153 of them being swine facilities. All analytes were detected, and detection frequencies ranged from 69 to 100% showing the persistence in the watershed. Antibiotics were detected at a higher frequency using POCIS compared to grab samples. We observed statistically significant seasonal trends for SMZ and ATZ concentrations during growing and harvest seasons. Time weighted average (TWA) concentrations quantified from the POCIS were 1.87ngL(-1) (SMZ), 0.30ngL(-1) (TYL), and 754.2ngL(-1) (ATZ) in the watershed. SMZ and TYL concentrations were lower than the minimum inhibitory concentrations (MIC) for E. coli. All analytes were detected in tile drain effluent, confirming tile drainage as a pathway for antibiotic transport. Our results identify the episodic occurrence of antibiotics, and highlights the importance identifying seasonal fate and occurrence of these analytes. Published by Elsevier B.V.

  2. Comments on the article by A. J. Lecloux (J Nanopart Res (2015) 17:447) regarding the use of volume-specific surface area (VSSA) to classify nanomaterials

    Science.gov (United States)

    Gibson, Neil; Rauscher, Hubert; Roebben, Gert

    2016-08-01

    In November 2015, an article by A. J. Lecloux was published in this journal (J Nanopart Res, 17:447, 2015). The article focused on the use of volume-specific surface area (VSSA) for the implementation of the European Commission's recommended definition of "nanomaterial". In that paper, VSSA values were calculated for polydisperse particulate materials using a particle number-based averaging method which do not agree with earlier results of VSSA simulations of polydisperse materials reported in 2014 by the Joint Research Centre (JRC) of the European Commission (EC). In this contribution, we explain the difference between traditional view of VSSA which was used by the JRC and the proposed model of Lecloux. Through the use of some simple examples for polydisperse materials, it is demonstrated that the latter produces values which neither correspond to the generally accepted definition of VSSA nor relate to the commonly used experimental methods for determining VSSA using gas adsorption. Lecloux's model therefore does not constitute a basis for practical implementation of the EC's definition of nanomaterial using gas adsorption techniques.

  3. Extracting Metrics for Three-dimensional Root Systems: Volume and Surface Analysis from In-soil X-ray Computed Tomography Data

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, Niraj; Stephens, Sean A.; Adams, Lexor; Beck, Anthon N.; McKinney, Adriana L.; Varga, Tamas

    2016-01-01

    Plant roots play a critical role in plant-soil-microbe interactions that occur in the rhizosphere, as well as processes with important implications to climate change and forest management. Quantitative size information on roots in their native environment is invaluable for studying root growth and environmental processes involving the plant. X ray computed tomography (XCT) has been demonstrated to be an effective tool for in situ root scanning and analysis. Our group at the Environmental Molecular Sciences Laboratory (EMSL) has developed an XCT-based tool to image and quantitatively analyze plant root structures in their native soil environment. XCT data collected on a Prairie dropseed (Sporobolus heterolepis) specimen was used to visualize its root structure. A combination of open-source software RooTrak and DDV were employed to segment the root from the soil, and calculate its isosurface, respectively. Our own computer script named 3DRoot-SV was developed and used to calculate root volume and surface area from a triangular mesh. The process utilizing a unique combination of tools, from imaging to quantitative root analysis, including the 3DRoot-SV computer script, is described.

  4. Effects of excipients on the tensile strength, surface properties and free volume of Klucel® free films of pharmaceutical importance

    Science.gov (United States)

    Gottnek, Mihály; Süvegh, Károly; Pintye-Hódi, Klára; Regdon, Géza

    2013-08-01

    The physicochemical properties of polymers planned to be applied as mucoadhesive films were studied. Two types of Klucel® hydroxypropylcellulose (LF and MF) were used as film-forming polymers. Hydroxypropylcellulose was incorporated in 2 w/w% with glycerol and xylitol as excipients and lidocaine base as an active ingredient at 5, 10 or 15 w/w% of the mass of the film-forming polymer. The free volume changes of the films were investigated by positron annihilation lifetime spectroscopy, the mechanical properties of the samples were measured with a tensile strength tester and contact angles were determined to assess the surface properties of the films. It was found that the Klucel® MF films had better physicochemical properties than those of the LF films. Klucel® MF as a film-forming polymer with lidocaine base and both excipients at 5 w/w% exhibited physicochemical properties and good workability. The excipients proved to exert strong effects on the physicochemical properties of the tested systems and it is very important to study them intensively in preformulation studies in the pharmaceutical technology in order to utilise their benefits and to avoid any disadvantageous effects.

  5. Hydrodynamic effects of the tip movement on surface nanobubbles: a combined tapping mode, lift mode and force volume mode AFM study.

    Science.gov (United States)

    Walczyk, Wiktoria; Hain, Nicole; Schönherr, Holger

    2014-08-28

    We report on an Atomic Force Microscopy (AFM) study of AFM tip-nanobubble interactions in experiments conducted on argon surface nanobubbles on HOPG (highly oriented pyrolytic graphite) in water in tapping mode, lift mode and Force Volume (FV) mode AFM. By subsequent data acquisition on the same nanobubbles in these three different AFM modes, we could directly compare the effect of different tip-sample interactions. The tip-bubble interaction strength was found to depend on the vertical and horizontal position of the tip on the bubble with respect to the bubble center. The interaction forces measured experimentally were in good agreement with the forces calculated using the dynamic interaction model. The strength of the hydrodynamic effect was also found to depend on the direction of the tip movement. It was more pronounced in the FV mode, in which the tip approaches the bubble from the top, than in the lift mode, in which the tip approaches the bubble from the side. This result suggests that the direction of tip movement influences the bubble deformation. The effect should be taken into account when nanobubbles are analysed by AFM in various scanning modes.

  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

    The overall goals of this doctoral dissertation are to provide knowledge of workers' exposure to nanomaterials and to assist in the development of standard methods to measure personal exposure to nanomaterials in workplace environments. To achieve the first goal, a field study investigated airborne particles generated from the weighing of bulk carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. This study also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood and biosafety cabinet) for control of exposure to particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured with direct-read instruments, and particle morphology was determined by electron microscopy. Sanding of CNT-epoxy nanocomposites released respirable size airborne particles with protruding CNTs very different in morphology from bulk CNTs that tended to remain in clusters (>1mum). Respirable mass concentrations in the operator's breathing zone were significantly greater when sanding took place in the custom hood (p 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

  7. Anatomic relationships of the distal and proximal radioulnar joints articulating surface areas, and of the radius and ulna bone volumes – implications for biomechanical studies of the distal and proximal radioulnar joints and forearm bones

    Directory of Open Access Journals (Sweden)

    Paul S C Malone

    2016-07-01

    Full Text Available BackgroundPrevious work from this laboratory has evidenced the biomechanical role of forearm osseoligamentous structures in load transfer of applied forces. It has shown that transmitted forces across the distal radioulnar joint (DRUJ and proximal radioulnar joint (PRUJ are similar though not identical under axial loading conditions. The purpose of the study was to assess the articulating surface areas of the radioulnar joints and the volumes of the forearm bones addressing the hypothesis that there may be anatomic adaptations that reflect the biomechanical function of the integrated forearm unit.MethodsThe articulating surface areas of PRUJ and DRUJ were assessed using a laser scanner in 24 cadaver forearms. The articulating joint surfaces were additionally delineated from standardized photographs assessed by three observers. The surface areas of matched pairs of joints were compared on the null hypothesis that these were the same within a given forearm specimen. An additional 44 pairs of matched forearm bone volumes were measured using water displacement technique and again compared through statistical analysis (paired sample t-test, and Bland Altman analysis.ResultsThe findings of this study are that the articulating surface areas of the DRUJ and PRUJ as well as the bone volumes are significantly different and yet strongly correlated. The paired sample t-test showed a significant difference between the surface areas of the DRUJ and PRUJ (p<0.05. The PRUJ articulating surface area was marginally larger than the DRUJ with a PRUJ : DRUJ ratio of 1.02. Paired sample t-test showed a significant difference between the two bone volumes (p<0.01 with a radius to ulna bone volume ratio of 0.81. When the olecranon was disregarded, radius volume was on average 4% greater than ulna volume.ConclusionsThis study demonstrated defines the anatomical relationships between the two forearm bones and their articulating joints when matched for specimen. The data

  8. Volume Entropy

    CERN Document Server

    Astuti, Valerio; Rovelli, Carlo

    2016-01-01

    Building on a technical result by Brunnemann and Rideout on the spectrum of the Volume operator in Loop Quantum Gravity, we show that the dimension of the space of the quadrivalent states --with finite-volume individual nodes-- describing a region with total volume smaller than $V$, has \\emph{finite} dimension, bounded by $V \\log V$. This allows us to introduce the notion of "volume entropy": the von Neumann entropy associated to the measurement of volume.

  9. System applications of high-Tc superconductor sampler cooled y a cryo-cooler; Reitoki reikyaku koon chodendo sanpura no shisutemu oyo

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, M.; Sato, T.; Tahara, S. [NEC Corp., Tokyo (Japan). Fundamental Research Laboratories

    1999-11-10

    It is possible to require these currents from the voltage measurement using the semiconductor sampler, if the impedance is known. However, the measurement was not possible for the current in LSI with the complicated layer structure, since the impedance is generally unknown. We develop 'the current measurement system' using characteristics of the high-temperature superconductivity sampler in order to solve this. In this system, the sampler chip is cooled to near 40K using the refrigerating machine. (NEDO)

  10. A comparison of the CATHIA-T sampler, the GK2.69 cyclone and the standard cowled sampler for thoracic fiber concentrations at a Taconite (iron ore)-processing mill.

    Science.gov (United States)

    Lee, Eun Gyung; Harper, Martin; Nelson, John; Hintz, Patrick J; Andrew, Michael E

    2008-01-01

    Several recommendations have been made to the effect that the most appropriate health-based size-selective criterion for fibers is the thoracic convention of the International Organization for Standardization (ISO). The performance of two thoracic samplers, the CATHIA-T (37-mm filter) and the GK2.69 cyclone (37-mm filter), was investigated against the standard 25-mm cowled sampler (current NIOSH 7400 standard method) to determine the effect of thoracic sampling on field results. A total of 270 samples: 80 field and 10 field blank samples for each sampler type, were taken from seven stations in the processing mill of an iron ore mine whose ore contains amphibole minerals. Slides were prepared using the dimethyl formamide/Euparal technique and relocatable cover slips. Two counters examined the slides according to NIOSH 7400 counting A rules with phase contrast microscopes. Prior to counting the sample slides, four reference slides were randomly selected and counted three times on different days to compare the coefficient of variation (CV) between and within counters. Also, seven reference slides were chosen to explore variability between the two microscopes. The average CV between counters (0.148) showed slightly higher than the average CVs within counters (0.072 for Counter 1 and 0.119 for Counter 2). The average CV between the two microscopes was 0.147. Compared to the standard cowled sampler, the overall fiber concentration was lower for the CATHIA-T sampler (CATHIA-T/Cowled = 0.63) and higher for the GK2.69 cyclone (GK2.69/Cowled = 1.66). The result for the CATHIA-T sampler is as expected from laboratory trials, but the result for the GK2.69 cyclone is not as expected. In conclusion, the CATHIA-T sampler has a potential advantage as a high-flow static sampler for screening coarse particles. However, these findings resulted from one field sampling site that contains amphibole minerals, not all of which are asbestiform. Thus, additional field samples from other

  11. Influence of volume percentage of NanoTiB2 particles on tribological & mechanical behaviour of 6061-T6 Al alloy nano-surface composite layer prepared via friction stir process

    Directory of Open Access Journals (Sweden)

    V. Kishan

    2017-02-01

    Full Text Available The aim of present study is to analyze the influence of volume percentage (vol.% of nano-sized particles (TiB2: average size is 35 nm on microstructure, mechanical and tribological behavior of 6061-T6 Al alloy surface nano composite prepared via Friction stir process (FSP. The microstructure of the fabricated surface nanocomposites is examined using optical microscopy (OM and scanning electron microscope (SEM for distribution of TiB2 nano reinforcement particles, thickness of nano composite layer formed on the Aluminum alloy substrate and fracture features. The depth of surface nano composite layer is measured as 3683.82 μm along the cross section of stir zone of nano composite perpendicular to FSP. It was observed that increase in volume percentage of TiB2 particles, the microhardness is increased up to 132 Hv and it is greater than as-received Al alloy's microhardness (104 Hv. It is also observed that at 4 volume percentage higher tensile properties exhibited as compared with the 2 and 8 vol. %. It is found that high wear resistance exhibited at 4 volume percentage as-compared with the 2 and 8 vol. %. The observed wear and mechanical properties are interrelated with microstructure, fractography and worn morphology.

  12. Sampling in the Great Lakes for pharmaceuticals, personal care products, and endocrine-disrupting substances using the passive polar organic chemical integrative sampler.

    Science.gov (United States)

    Li, Hongxia; Helm, Paul A; Metcalfe, Chris D

    2010-04-01

    The passive polar organic chemical integrative sampler in the pharmaceutical configuration (i.e., pharmaceutical-POCIS) was calibrated for sampling at water temperatures of 5, 15 and 25 degrees C to determine the influence of temperature on chemical-specific sampling rates (R(S)), thus providing more robust estimates of the time-weighted average concentrations of pharmaceuticals and personal care products (PPCPs) and endocrine-disrupting substances (EDS) in surface water. The effect of water temperature and flow on the R(S) of these analytes was evaluated in the laboratory with a static system. The loss of the test compounds from water by uptake into POCIS was linear over an 8-d period, and these experimental data yielded R(S) values in the range of 0.07 to 2.46 L/d across the temperature range for the 30 compounds tested. Water temperature and flow influenced POCIS uptake rates, but these effects were relatively small, which is consistent with the theory for uptake into POCIS samplers. Therefore, under a narrow range of water temperatures and flows, it may not be necessary to adjust the R(S) for POCIS. Except for acidic drugs and sulfonamide antibiotics, R(S) values were positively correlated with octanol-water partition coefficients (log K(OW)) of the test compounds. A linear relationship was also observed between R(S) and chromatographic retention times on a C18 reversed-phase column. These observations may provide a rapid method for estimating the R(S) of additional chemicals in the POCIS. The application of the R(S) to POCIS deployed for one month in Lake Ontario, Canada, during the summers of 2006 and 2008 yielded estimates of PPCP and EDS concentrations that are consistent with conventional concentration measurements of these compounds in Lake Ontario surface water. (c) 2009 SETAC.

  13. 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.

  14. In situ measurement of PCB pore water concentration profiles in activated carbon-amended sediment using passive samplers.

    Science.gov (United States)

    Oen, Amy M P; Janssen, Elisabeth M L; Cornelissen, Gerard; Breedveld, Gijs D; Eek, Espen; Luthy, Richard G

    2011-05-01

    Vertical pore water profiles of in situ PCBs were determined in a contaminated mudflat in San Francisco Bay, CA, 30 months after treatment using an activated carbon amendment in the upper layer of the sediment. Pore water concentrations were derived from concentrations of PCBs measured in two passive samplers; polyethylene (PE, 51 μm thick) and polyoxymethylene (POM, 17 μm thick) at different sediment depths. To calculate pore water concentrations from PCB contents in the passive samplers, an equilibrium approach and a first-order uptake model were applied, using five performance reference compounds to estimate pore water sampling rates. Vertical pore water profiles showed good agreement among the measurement and calculation methods with variations within a factor of 2, which seems reasonable for in situ measurements. The close agreements of pore water estimates for the two sampler materials (PE and POM) and the two methods used to translate uptake in samplers to pore water concentrations demonstrate the robustness and suitability of the passive sampling approach. The application of passive samplers in the sediment presents a promising method for site monitoring and remedial treatment evaluation of sorbent amendment or capping techniques that result in changes of pore water concentrations in the sediment subsurface.

  15. Development of the performance reference compound approach for the calibration of "polar organic chemical integrative sampler" (POCIS).

    Science.gov (United States)

    Belles, Angel; Tapie, Nathalie; Pardon, Patrick; Budzinski, Hélène

    2014-02-01

    The purpose of the Water Framework Directive is to ensure the quality of the natural water across Europe. In this context, passive samplers have shown interesting capacities for the monitoring of contaminants in aqueous ecosystems. They allow the measurement of time-weighted average concentrations, overcoming many drawbacks of the spot-sampling techniques known to be expensive and time consuming. However, application of passive samplers such as polar organic chemical integrative samplers (POCIS) for the monitoring of hydrophilic contaminants requires calibration to define compound sampling rates; key parameters to deduce the pollutant water concentrations from the amounts of pollutants accumulated by the device. Unfortunately, sampling rates are influenced by a range of environmental factors; in that respect, a question remains: is it not evident to know to what extent the sampling rates obtained in laboratory experiments can be used in field conditions? The problem can be solved for hydrophobic samplers by using performance reference compounds (PRCs), and an ongoing challenge for POCIS is focused on the improvement of the quantitative aspect of this family of samplers. In this study, potential PRCs have been selected during a specific experiment and their performance was tested in the laboratory under two hydrodynamic conditions. Results revealed a good proportionality between elimination rates of PRCs and sampling rates of chemicals. Afterwards, the application of the approach under environmental conditions was assessed by deploying POCIS in the Arcachon Bay (France) where POCIS-PRC-derived water concentrations appear to be close to the simultaneous grab-sampling results.

  16. Fast monitoring of indoor bioaerosol concentrations with ATP bioluminescence assay using an electrostatic rod-type sampler.

    Science.gov (United States)

    Park, Ji-Woon; Park, Chul Woo; Lee, Sung Hwa; Hwang, Jungho

    2015-01-01

    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: 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.

  17. Using performance reference compounds in polyethylene passive samplers to deduce sediment porewater concentrations for numerous target chemicals.

    Science.gov (United States)

    Fernandez, Loretta A; Harvey, Charles F; Gschwend, Philip M

    2009-12-01

    Polymeric passive samplers are useful for assessing hydrophobic organic chemical contamination in sediment beds. Here, an improved method is described for measuring concentrations of contaminants in porewater by using performance reference compounds (deuterated phenanthrene, pyrene, and chrysene) to calibrate sampler/site-specific mass transfer behavior. The method employs a one-dimensional diffusion model of chemical exchange between a polymer sheet of finite thickness and an unmixed sediment bed. The model is parametrized by diffusivities and partition coefficients for both the sampler and sediment. This method was applied to estimate porewater concentrations for seventeen PAHs from polymeric samplers deployed for 3-10 days in homogenized sediment from a coal-tar contaminated site. The accuracy of the method was verified by comparing the passive sampler results to concentrations measured through liquid-liquid extraction of physically separated porewaters, with corrections for sorption to colloidal organic carbon. The measurements made using the two methods matched within about a factor of 2.0 (+/-0.9) for the 17 target PAHs.

  18. Development of a passive sampler for Zinc(II) in urban pond waters using a polymer inclusion membrane.

    Science.gov (United States)

    Almeida, M Inês G S; Chan, Cleopas; Pettigrove, Vincent J; Cattrall, Robert W; Kolev, Spas D

    2014-10-01

    The use of a polymer inclusion membrane (PIM) in a novel passive sampler to measure the time-weighted average concentration of Zn(II) in urban waters is described. The passive sampler consists of a compartment containing an acidic receiving solution, which is separated from the external source solution by a PIM consisting of 40 wt% di-2-(ethylhexyl) phosphoric acid as the extractant, and 60 wt% poly-(vinyl chloride) as the base polymer. Two laboratory passive sampling techniques were tested. One involved immersion of the passive sampler into a source solution ("dip-in" approach) for a predetermined period of time while in the other one the source solution was flown past the membrane of the sampler ("flow-through" approach). The latter approach was found to be more suitable for the calibration of the passive sampler under laboratory conditions. A successful application using the "dip-in" sampling approach in urban waters has been conducted for proof of concept.

  19. 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.

  20. Environmental Report 1996, Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Harrach, R.J.

    1996-01-01

    This is Volume 2 of the Lawrence Livermore National Laboratory`s (LLNL`s) annual Environmental Report 1996, prepared for the US Department of Energy. Volume 2 supports Volume 1 summary data and is essentially a detailed data report that provides individual data points, where applicable. Volume 2 includes information on monitoring of air, air effluents, sewerable water, surface water, ground water, soil and sediment, vegetation and foodstuff, environmental radiation, and quality assurance.

  1. 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.

  2. Mexican Cervical Cancer Screening Study II: acceptability of human papillomavirus self-sampler.

    Science.gov (United States)

    Arriba, Lucybeth Nieves; Enerson, Christine L; Belinson, Suzanne; Novick, Loyd; Belinson, Jerome

    2010-11-01

    Cervical cancer is the second most common cancer in women worldwide. In countries like Mexico, cervical cancer early detection programs have had a minimal impact on the incidence and death rates from cervical cancer. Self-sampling for the presence of high-risk human papillomavirus is potentially a more effective screening tool to reach women who have limited access to community healthcare resources. The objective of this phase 2 trial was to establish if the fourth generation Preventive Oncology International/National Institutes of Health self-sampler device is well accepted by women of all socioeconomic levels in Michoacán, Mexico. This is a prospective phase 2 trial. The patients used the self-sampler, and then the acceptability questionnaire (14 multiple choice questions) was completed with the assistance of nursing staff. Two thousand five hundred seventeen patients completed the questionnaire. The mean age of our patient population was 39 years. Eighty-six percent of patients reported being comfortable when using the self-test, and 76% preferred to do the test at the clinic. Ninety-one percent of patients said that if their only choice was to perform the test at home they would perform it rather than not perform the test. The major barriers for the use of self-sampler identified by the women in the study were fear (75%), woman might not perform the test because she does not feel ill (70%), women felt that husbands may stand in women's way of performing the test (66%), and lack of time (61%). Results differed by location but not by history of Papanicolaou test. Most patients reported being comfortable when using the Preventive Oncology International/National Institutes of Health fourth generation self-test. Most influential barriers identified by the acceptability questionnaire were fear, lack of signs or symptoms of illness, husbands' influence, cost, lack of time, being unable to read, and lack of trust in the medical community.

  3. Subsurface Environment Sampler for Improved In Situ Characterization of Subsurface Microbial Communities

    Science.gov (United States)

    Barnhart, E. P.; Ruppert, L. F.; Orem, W. H.; McIntosh, J. C.; Cunningham, A. B.; Fields, M. W.; Hiebert, R.; Hyatt, R.

    2016-12-01

    There is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by the extraction and transport of fossil fuels. This threat increases the need for improved groundwater monitoring and the ability to predict the extent to which microbial activity may remediate such contamination. The characterization of subsurface microbial communities could provide an ideal biomonitoring tool for the assessment of subsurface contamination due to prokaryotes environmental ubiquity, rapidity of response to environmental perturbation and the important role they play in hydrocarbon degradation and bioremediation. New DNA sequencing technologies provide the opportunity to cost-effectively identify the vast subsurface microbial ecosystem, but use of this new technology is restricted due to issues with sampling. Prior subsurface microbiology studies have relied on core samples that are expensive to obtain hard to collect aseptically and/or ground water samples that do not reflect in situ microbial densities or activities. The development of down-well incubation of sterile sediment with a Diffusive Microbial Sampler (DMS) has emerged as an alternative method to sample subsurface microbial communities that minimizes cost and contamination issues associated with traditional methods. We have designed a Subsurface Environment Sampler with a DMS module that could enable the anaerobic transport of the in situ microbial community from the field for laboratory bioremediation studies. This sampler could provide an inexpensive and standard method for subsurface microbial sampling which would make this tool useful for Federal, State, private and local agencies interested in monitoring contamination or the effectiveness of bioremediation activities in subsurface aquifers.

  4. 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.

  5. Temperature dependence on the pesticide sampling rate of polar organic chemical integrative samplers (POCIS).

    Science.gov (United States)

    Yabuki, Yoshinori; Nagai, Takashi; Inao, Keiya; Ono, Junko; Aiko, Nobuyuki; Ohtsuka, Nobutoshi; Tanaka, Hitoshi; Tanimori, Shinji

    2016-10-01

    Laboratory experiments were performed to determine the sampling rates of pesticides for the polar organic chemical integrative samplers (POCIS) used in Japan. The concentrations of pesticides in aquatic environments were estimated from the accumulated amounts of pesticide on POCIS, and the effect of water temperature on the pesticide sampling rates was evaluated. The sampling rates of 48 pesticides at 18, 24, and 30 °C were obtained, and this study confirmed that increasing trend of sampling rates was resulted with increasing water temperature for many pesticides.

  6. Ohm's law, Fick's law, and diffusion samplers for gases

    Energy Technology Data Exchange (ETDEWEB)

    Palmes, E.D.; Lindenboom, R.H.

    1979-12-01

    In the diffusion sampler, the coefficient of diffusion of a gas in air and the geometry of the tube were treated separately. The diffusional flux through the tube was calculated using JA = D(A/L)c and for electrical current through a conductor I = E/R where I = current (C/s), E = potential difference (V), and R = resistance (ohms). Resistance to diffusional flux was expressed as L/A. The similarities between Fick's law and Ohm's law were concentrated on; a series of NO/sub 2/ samplers were modified. The total resistance to diffusion of the two tubes in series (L/sup 1//A/sup 1/) was calculated from the relationship: (L/sup 1//A/sup 1/ = L/sub 1/-L/sub 2//A/sub 1/ + L/sub 2//A/sub 2/) where L/sub 1/ and A/sub 1/ are length and cross-sectional area of tube 1, and L/sub 2/ and A/sub 2/ are length and cross-sectional area of tube 2. In all cases A/sub 1/ was 0.713 cm/sup 2/, L/sub 1/ was 7.10 cm, and A/sub 2/ was 0.079 cm/sup 2/. The quantities of NO/sub 2/ captured by the samplers in each of three runs were shown as percent of the amount captured by the unaltered (L/sub 2/=O) samplers. Actual quantities of NO/sub 2/ captured and relative diffusional fluxes predicted from tube dimensions are included. Linear regression analysis comparing experimental values with those predicted from A/sup 1//L/sup 1/ gave the following results for runs 1, 2, 3, and average, respectively: slope 0.995, 1.007, 0.993, and 0.999; intercept -0.07, -1.59, 0.06, and -0.52; correlation 0.999 in all cases. Thus, the results fit the theory well within limits of accuracy of the test systems, and demonstrate that diffusional resistances in series, like electrical resistances, are additive. 1 figure, 1 table. (DP)

  7. Estimating the parameters of dynamical systems from Big Data using Sequential Monte Carlo samplers

    Science.gov (United States)

    Green, P. L.; Maskell, S.

    2017-09-01

    In this paper the authors present a method which facilitates computationally efficient parameter estimation of dynamical systems from a continuously growing set of measurement data. It is shown that the proposed method, which utilises Sequential Monte Carlo samplers, is guaranteed to be fully parallelisable (in contrast to Markov chain Monte Carlo methods) and can be applied to a wide variety of scenarios within structural dynamics. Its ability to allow convergence of one's parameter estimates, as more data is analysed, sets it apart from other sequential methods (such as the particle filter).

  8. Application of sorbent impregnated polyurethane foam (SIP) disk passive air samplers for investigating organochlorine pesticides and polybrominated diphenyl ethers at the global scale.

    Science.gov (United States)

    Koblizkova, Martina; Genualdi, Susan; Lee, Sum Chi; Harner, Tom

    2012-01-03

    As part of continued efforts under the Global Atmospheric Passive Sampling (GAPS) Network to develop passive air samplers applicable to a wide-range of compounds, sorbent-impregnated polyurethane foam (SIP) disk samplers were codeployed and tested against conventional polyurethane foam (PUF) disk samplers. The SIP disk sampler has a higher sorptive capacity compared to the PUF disk sampler, due to its impregnation with ground XAD resin. The two sampler types were codeployed at 20 sites during the 2009, 3-month long spring sampling period of the GAPS Network. Air concentrations for chlordanes (trans-chlordane, cis-chlordane, and trans-nonachlor) and endosulfans (endosulfan I, endosulfan II, and endosulfan sulfate) derived from PUF disk and SIP disk samplers showed near 1:1 agreement and confirmed previous results for polychlorinated biphenyls (PCBs). Discrepancies observed for α-HCH and γ-HCH in PUF disk versus SIP disk are attributed to lack of "comparability" of the PUF and SIP data sets, due to differences in effective air sampled by the two devices caused by saturation of these higher volatility compounds in the lower capacity PUF disk samplers. Analysis of PBDEs in PUF and SIP disks showed relatively good agreement but highlighted challenges associated with high blanks levels for PBDEs. The higher capacity SIP disk samplers allowed for the analysis of pentachlorobenzene (PeCBz) and hexachlorobenzene (HCBz) and revealed a relatively uniform global distribution of these compounds. The results of this study further validate the SIP disk sampler as a complement to the PUF disk sampler, with capabilities for a broad range of POPs targeted under international POPs treaties such as the Stockholm Convention on POPs and its Global Monitoring Plan.

  9. Surface area and volume measurements of volcanic ash particles using micro-computed tomography (micro-CT): A comparison with scanning electron microscope (SEM) stereoscopic imaging and Brunauer-Emmett-Teller (BET) model

    Science.gov (United States)

    Ersoy, Orkun; Şen, Erdal; Aydar, Erkan; Tatar, Ä.°Lkan; Ćelik, H. Hamdi

    2010-05-01

    Volcanic ash particles are important components of explosive eruptions and their surface texture is the subject of intense research. Characterization of ash surfaces is crucial for understanding the physics of the volcanic plumes, remote sensing measurements of ash and aerosols, interfacial processes, modelling transportation and deposition of tephra and characterizing eruptive styles. A number of different methods have been used over the years to arrive at surface area estimates. The more common methods include estimates based on the geometric considerations (geometric surface area) and the physisorption of gas molecules on the surface of interest (physical surface area). In this study, micro computed tomography (micro-CT), a non-destructive method providing three-dimensional data enabled the measurement of surface areas and volumes of individual ash particles. Specific surface area estimates for ash particles were also obtained using nitrogen as gas adsorbent and the BET (Brunauer-Emmett-Teller) model. Results were compared with the values obtained from SEM stereoscopic imaging and geometric considerations. Surface area estimates of micro-CT and SEM stereoscopic imaging overlaps with mean specific surface area results of 0.0167 and 0.0214 m2/g, respectively. However, ash particle surface textures present quite a deviation from that of their geometric forms and approximation to sphere and ellipsoid both seemed to be inadequate for representation of real ash surfaces. The higher surface area estimate (> 0.4 m2/g) obtained from the technique based on physical sorption of gases (BET model here) was attributed to its capability for surface areas associated even with angstrom-sized pores. SEM stereoscopic and/or micro-CT imaging were suggested for characterization of textures on macro-pore regions of ash particles.

  10. Experiences and issues with the implementation of microscreen multilevel groundwater samplers in glaciofluvial aquifers in Southern Norway

    Science.gov (United States)

    Kracht, Oliver; Dagestad, Atle

    2013-04-01

    Scandinavia many of the most important groundwater resources are situated in glaciofluvial sediments, which are commonly characterised by a high degree of heterogeneity (very coarse to very fine material). This significantly reduces the number of suitable drilling techniques and imposes several restrictions with regard to the connection of filter elements to the surrounding aquifer, and the vertical isolation between the different sampling levels (hole seal quality and vertical flows). Another important mater is the general ease and the cost of installation (which clearly depends on the local availability of certain drilling techniques and services, and the availability of material for well construction). We summarize our experiences gained by using various setups of small volume multi-level samplers with microscreens in unconsolidated sedimentary aquifers at two different experimental sites in S-Norway. Experiments were conducted during year 2010 and 2011 in fine to coarse grained glaciofluvial deposits in the eastern part of the Gardermoen / Øvre Romerike Aquifer (Ullensaker), and in coarse grained glaciofluvial deposits at the Granli waterworks (Kongsvinger). Installations were performed using different drilling techniques (5/4 inch Pionjär handheld drilling equipment, geotechnical drilling rig percussion drilling, and 163 mm ODEX drilling). Samples were extracted by using a multi channel peristaltic suction pump under low flow rates. The suitability of different types of tubing and filter materials has been investigated by checking for unwanted leaching of inorganic compounds.

  11. 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.

  12. 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.

  13. Determination of sample size for a multi-class classifier based on single-nucleotide polymorphisms: a volume under the surface approach.

    Science.gov (United States)

    Liu, Xinyu; Wang, Yupeng; Sriram, T N

    2014-06-14

    Data on single-nucleotide polymorphisms (SNPs) have been found to be useful in predicting phenotypes ranging from an individual's class membership to his/her risk of developing a disease. In multi-class classification scenarios, clinical samples are often limited due to cost constraints, making it necessary to determine the sample size needed to build an accurate classifier based on SNPs. The performance of such classifiers can be assessed using the Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) for two classes and the Volume Under the ROC hyper-Surface (VUS) for three or more classes. Sample size determination based on AUC or VUS would not only guarantee an overall correct classification rate, but also make studies more cost-effective. For coded SNP data from D(≥2) classes, we derive an optimal Bayes classifier and a linear classifier, and obtain a normal approximation to the probability of correct classification for each classifier. These approximations are then used to evaluate the associated AUCs or VUSs, whose accuracies are validated using Monte Carlo simulations. We give a sample size determination method, which ensures that the difference between the two approximate AUCs (or VUSs) is below a pre-specified threshold. The performance of our sample size determination method is then illustrated via simulations. For the HapMap data with three and four populations, a linear classifier is built using 92 independent SNPs and the required total sample sizes are determined for a continuum of threshold values. In all, four different sample size determination studies are conducted with the HapMap data, covering cases involving well-separated populations to poorly-separated ones. For multi-classes, we have developed a sample size determination methodology and illustrated its usefulness in obtaining a required sample size from the estimated learning curve. For classification scenarios, this methodology will help scientists determine whether a sample

  14. Analysis techniques and performance of the Domino Ring Sampler version 4 based readout for the MAGIC telescopes

    CERN Document Server

    Sitarek, Julian; Mazin, Daniel; Paoletti, Riccardo; Tescaro, Diego

    2013-01-01

    Recently the readout of the MAGIC telescopes has been upgraded to a new system based on the Domino Ring Sampler version 4 chip. We present the analysis techniques and the signal extraction performance studies of this system. We study the behaviour of the baseline, the noise, the cross-talk, the linearity and the time resolution. We investigate also the optimal signal extraction. In addition we show some of the analysis techniques specific to the readout based on the Domino Ring Sampler version 2 chip, previously used in the MAGIC II telescope.

  15. 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

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

    Science.gov (United States)

    Wetzel, Todd A; Doucette, William J

    2015-03-01

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

  17. Development of a passive, in situ, integrative sampler for hydrophilic organic contaminants in aquatic environments

    Science.gov (United States)

    Alvarez, D.A.; Petty, J.D.; Huckins, J.N.; Jones-Lepp, T. L.; Getting, D.T.; Goddard, J.P.; Manahan, S.E.

    2004-01-01

    Increasingly it is being realized that a holistic hazard assessment of complex environmental contaminant mixtures requires data on the concentrations of hydrophilic organic contaminants including new generation pesticides, pharmaceuticals, personal care products, and many chemicals associated with household, industrial, and agricultural wastes. To address this issue, we developed a passive in situ sampling device (the polar organic chemical integrative sampler [POCIS]) that integratively concentrates trace levels of complex mixtures of hydrophilic environmental contaminants, enables the determination of their time-weighted average water concentrations, and provides a method of estimating the potential exposure of aquatic organisms to the complex mixture of waterborne contaminants. Using a prototype sampler, linear uptake of selected herbicides and pharmaceuticals with log KowS < 4.0 was observed for up to 56 d. Estimation of the ambient water concentrations of chemicals of interest is achieved by using appropriate uptake models and determination of POCIS sampling rates for appropriate exposure conditions. Use of POCIS in field validation studies targeting the herbicide diuron in the United Kingdom resulted in the detection of the chemical at estimated concentrations of 190 to 600 ng/L. These values are in agreement with reported levels found in traditional grab samples taken concurrently.

  18. PeGS: Perturbed Gibbs Samplers that Generate Privacy-Compliant Synthetic Data

    Directory of Open Access Journals (Sweden)

    Yubin Park

    2014-12-01

    Full Text Available This paper proposes a categorical data synthesizer algorithm that guarantees a quantifiable disclosure risk. Our algorithm, named Perturbed Gibbs Sampler (PeGS, can handle high-dimensional categorical data that are intractable if represented as contingency tables. PeGS involves three intuitive steps: 1 disintegration, 2 noise injection, and 3 synthesis. We first disintegrate the original data into building blocks that (approximately capture essential statistical characteristics of the original data. This process is efficiently implemented using feature hashing and non-parametric distribution approximation. In the next step, an optimal amount of noise is injected into the estimated statistical building blocks to guarantee differential privacy or l-diversity. Finally, synthetic samples are drawn using a Gibbs sampler approach. California Patient Discharge data are used to demonstrate statistical properties of the proposed synthetic methodology. Marginal and conditional distributions as well as regression coefficients obtained from the synthesized data are compared to those obtained from the original data. Intruder scenarios are simulated to evaluate disclosure risks of the synthesized data from multiple angles. Limitations and extensions of the proposed algorithm are also discussed.

  19. Smart Analogue Sampler for the Optical Module of a Cherenkov Neutrino Detector

    CERN Document Server

    Caponetto, L; Russo, G V; Randazzo, N

    2009-01-01

    A transient waveform sampler/recorder IC has been developed and realized in AMS C35B4 technology. This chip has been designed to fit the needs of a proposal for a front-end architecture for the readout of the anode signal of the photomultipliers in an underwater neutrino telescope. The design is based around a 3 channels x 32 cells switched capacitor array unit sampling its voltage inputs at 200MHz external clock rate and transferring the stored analogue voltage samples to its single analogue output at 1/10th of the sampling rate. This unit is replicated inside the ASIC providing 4 independent analogue sampling queues for signal transients up to 32 x 5 ns and a fifth unit storing transients up to 128 x 5 ns. A micro-pipelined unit, based on Muller C-gates, controls the 5 independent samplers. This paper briefly summarizes the complete front-end architecture and discusses in more detail the internal structure of the ASIC and its first functional tests.

  20. 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.