WorldWideScience

Sample records for monitor vapor tracer

  1. Vapor concentration monitor

    Science.gov (United States)

    Bayly, John G.; Booth, Ronald J.

    1977-01-01

    An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

  2. Preliminary assessment of halogenated alkanes as vapor-phase tracers

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Michael C.; Moore, Joseph N.; Hirtz, Paul

    1991-01-01

    New tracers are needed to evaluate the efficiency of injection strategies in vapor-dominated environments. One group of compounds that seems to meet the requirements for vapor-phase tracing are the halogenated alkanes (HCFCs). HCFCs are generally nontoxic, and extrapolation of tabulated thermodynamic data indicate that they will be thermally stable and nonreactive in a geothermal environment. The solubilities and stabilities of these compounds, which form several homologous series, vary according to the substituent ratios of fluorine, chlorine, and hydrogen. Laboratory and field tests that will further define the suitability of HCFCs as vapor-phase tracers are under way.

  3. Tracer monitoring of enhanced oil recovery projects

    Directory of Open Access Journals (Sweden)

    Kleven R.

    2013-05-01

    Full Text Available In enhanced oil recovery (EOR, chemicals are injected into the oil reservoir, either to increase macroscopic sweep efficiency, or to reduce remaining oil saturation in swept zones. Tracers can be used to identify reservoirs that are specifically suited for EOR operations. Injection of a selection of partitioning tracers, combined with frequent sample analysis of produced fluids, provides information suited for estimation of residual oil saturation. Tracers can also be used to evaluate and optimize the application of EOR chemicals in the reservoir. Suitable tracers will follow the EOR chemicals and assist in evaluation of retention, degradation or trapping. In addition to field applications, tracers also have a large potential as a tool to perform mechanistic studies of EOR chemicals in laboratory experiments. By labelling EOR chemicals with radioactive isotopes of elements such as H, C and S, detailed studies of transport mechanisms can be carried out. Co-injection of labelled compounds in dynamic flooding experiments in porous media will give information about retention or separation of the unique compounds constituting the chemical formulation. Separation of such compounds may be detrimental to obtaining the EOR effect expected. The paper gives new information of specific methods, and discusses current status for use of tracers in EOR operations.

  4. TRACER-II: a complete computational model for mixing and propagation of vapor explosions

    Energy Technology Data Exchange (ETDEWEB)

    Bang, K.H. [School of Mechanical Engineering, Korea Maritime Univ., Pusan (Korea, Republic of); Park, I.G.; Park, G.C.

    1998-01-01

    A vapor explosion is a physical process in which very rapid energy transfer occurs between a hot liquid and a volatile, colder liquid when the two liquids come into a sudden contact. For the analyses of potential impacts from such explosive events, a computer program, TRACER-II, has been developed, which contains a complete description of mixing and propagation phases of vapor explosions. The model consists of fuel, fragmented fuel (debris), coolant liquid, and coolant vapor in two-dimensional Eulerian coordinates. The set of governing equations are solved numerically using finite difference method. The results of this numerical simulation of vapor explosions are discussed in comparison with the recent experimental data of FARO and KROTOS tests. When compared to some selected FARO and KROTOS data, the fuel-coolant mixing and explosion propagation behavior agree reasonably with the data, although the results are yet sensitive primarily to the melt breakup and fragmentation modeling. (author)

  5. A monitoring system of radioactive tracers in hydroponic solution for research on plant physiology

    Energy Technology Data Exchange (ETDEWEB)

    Suzui, N.; Kawachi, N.; Ishioka, N.; Fujimaki, S. [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Yamaguchi, M. [Takasaki Advanced Radiation Research Institute, Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan)

    2009-07-01

    The mechanism of nutrient uptake in plants has received considerable attention in the field of plant science. Here we describe the development of a new monitoring system of radioactive tracers in hydroponic solution, which enables the noninvasive measurement of radioactive tracer uptake by an intact plant. In addition, we incorporated a weighing instrument into this system in order to simultaneously monitor water uptake by the same plant. For an evaluation of this monitoring system, we conducted a tracer experiment with a rice plant and a positron-emitting radioactive tracer, and successfully obtained continuous data for the amounts of radioactive tracer and water taken up by the intact plant over 36 h. (authors)

  6. Estimation of Recharge from Long-Term Monitoring of Saline Tracer Transport Using Electrical Resistivity Tomography

    DEFF Research Database (Denmark)

    Haarder, Eline Bojsen; Jensen, Karsten Høgh; Binley, Andrew;

    2015-01-01

    The movement of a saline tracer added to the soil surface was monitored in the unsaturated zone using cross-borehole electrical resistivity tomography (ERT) and subjected to natural rainfall conditions. The ERT data were inverted and corrected for subsurface temperature changes, and spatial moment...... methods. In September 2011, a saline tracer was added across a 142-m2 area at the surface at an application rate mimicking natural infiltration. The movement of the saline tracer front was monitored using cross-borehole electrical resistivity tomography (ERT); data were collected on a daily to weekly...... basis and continued for 1 yr after tracer application. The ERT data were inverted and corrected for temperature changes in the subsurface, and spatial moment analysis was used to calculate the tracer mass, position of the center of mass, and thereby the downwardly recharging flux. The recovered mass...

  7. Atmospheric tracer monitoring and surface plume development at the ZERT pilot test in Bozeman, Montana, USA

    Energy Technology Data Exchange (ETDEWEB)

    Wells, Arthur [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Strazisar, Brian [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Rodney Diehl, J. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Veloski, Garret [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2010-03-01

    A controlled release of CO2 was conducted at a field site in Bozeman, Montana, USA in July of 2008 in a multi-laboratory study of near surface transport and detection technologies. The development of a subsurface CO2 plume near the middle packer section of the horizontal release was studied using soil-gas and surface flux measurements of CO2. A perfluorocarbon tracer was added to the CO2 released from this section of the horizontal well, and the development of atmospheric plumes of the tracer was studied under various meteorological conditions using horizontal and vertical grids of monitors containing sorbent material to collect the tracer. This study demonstrated the feasibility of using remote sensing for the ultra low level detection of atmospheric plumes of tracers as means to monitor the near surface leakage of sequestered CO2.

  8. Vapor Online Monitor Model of Vapor Power Station Based on UML

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We presents a vapor online monitor system model of vapor power station developed by visual tool rational rose2000. Use cases such as on line instrument (onlineinstr), control, query, report, real database (realdb) and alarm are generated according to the system requirements. Use case view and class view of the system are formed at the same time. As for all the UML models of the system, this paper focuses the discussion on the class view, the component diagram of the control class and the sequence diagram of the query class. Corresponding C++ codes are produced and finally transferred into the spot running software.

  9. Atmospheric monitoring of a perfluorocarbon tracer at the 2009 ZERT Center experiment

    Science.gov (United States)

    Pekney, Natalie; Wells, Arthur; Rodney Diehl, J.; McNeil, Matthew; Lesko, Natalie; Armstrong, James; Ference, Robert

    2012-02-01

    Field experiments at Montana State University are conducted for the U.S. Department of Energy as part of the Zero Emissions Research and Technology Center (ZERT) to test and verify monitoring techniques for carbon capture and storage (CCS). A controlled release of CO 2 with an added perfluorocarbon tracer was conducted in July 2009 in a multi-laboratory study of atmospheric transport and detection technologies. Tracer plume dispersion was measured with various meteorological conditions using a tethered balloon system with Multi-Tube Remote Samplers (MTRS) at elevations of 10 m, 20 m, and 40 m above ground level (AGL), as well as a ground-based portable tower with monitors containing sorbent material to collect the tracer at 1 m, 2 m, 3 m, and 4 m AGL. Researchers designed a horizontal grid of sampling locations centered at the tracer plume source, with the tower positioned at 10 m and 30 m in both upwind and downwind directions, and the MTRS spaced at 50 m and 90 m downwind and 90 m upwind. Tracer was consistently detected at elevated concentrations at downwind sampling locations. With very few exceptions, higher tracer concentrations correlated with lower elevations. Researchers observed no statistical difference between sampling at 50 m and 90 m downwind at the same elevation. The US EPA AERMOD model applied using site-specific information predicted transport and dispersion of the tracer. Model results are compared to experimental data from the 2009 ZERT experiment. Successful characterization of the tracer plume simulated by the ZERT experiment is considered a step toward demonstrating the feasibility of remote sampling with unmanned aerial systems (UAS's) at future sequestration sites.

  10. Ambient changes in tracer concentrations from a multilevel monitoring system in Basalt

    Science.gov (United States)

    Bartholomay, Roy C.; Twining, Brian V.; Rose, Peter E.

    2014-01-01

    Starting in 2008, a 4-year tracer study was conducted to evaluate ambient changes in groundwater concentrations of a 1,3,6-naphthalene trisulfonate tracer that was added to drill water. Samples were collected under open borehole conditions and after installing a multilevel groundwater monitoring system completed with 11 discrete monitoring zones within dense and fractured basalt and sediment layers in the eastern Snake River aquifer. The study was done in cooperation with the U.S. Department of Energy to test whether ambient fracture flow conditions were sufficient to remove the effects of injected drill water prior to sample collection. Results from thief samples indicated that the tracer was present in minor concentrations 28 days after coring, but was not present 6 months after coring or 7 days after reaming the borehole. Results from sampling the multilevel monitoring system indicated that small concentrations of the tracer remained in 5 of 10 zones during some period after installation. All concentrations were several orders of magnitude lower than the initial concentrations in the drill water. The ports that had remnant concentrations of the tracer were either located near sediment layers or were located in dense basalt, which suggests limited groundwater flow near these ports. The ports completed in well-fractured and vesicular basalt had no detectable concentrations.

  11. Design of a perfluorocarbon tracer based monitoring network to support monitoring verification and accounting of sequestered CO2

    Science.gov (United States)

    Watson, T.; Sullivan, T.

    2013-05-01

    The levels of CO2 in the atmosphere have been growing since the beginning of the industrial revolution. The current level is 391 ppm. If there are no efforts to mitigate CO2 emissions, the levels will rise to 750 ppm by 2100. Geologic carbon sequestration is one strategy that may be used to begin to reduce emissions. Sequestration will not be effective unless reservoir leak rates are significantly less than 1%. There must be rigorous monitoring protocols in place to ensure sequestration projects meet regulatory and environmental goals. Monitoring for CO2 leakage directly is difficult because of the large background levels and variability of CO2 in the atmosphere. Using tracers to tag the sequestered CO2 can mitigate some of the difficulties of direct measurement but a tracer monitoring network and the levels of tagging need to be carefully designed. Simple diffusion and dispersion models are used to predict the surface and atmospheric concentrations that would be seen by a network monitoring a sequestration site. Levels of tracer necessary to detect leaks from 0.01 to 1% are presented and suggestions for effective monitoring and protection of global tracer utility are presented.

  12. Design of a perfluorocarbon tracer based monitoring network to support monitoring verification and accounting of sequestered CO2

    Directory of Open Access Journals (Sweden)

    Sullivan T.

    2013-05-01

    Full Text Available The levels of CO2 in the atmosphere have been growing since the beginning of the industrial revolution. The current level is 391 ppm. If there are no efforts to mitigate CO2 emissions, the levels will rise to 750 ppm by 2100. Geologic carbon sequestration is one strategy that may be used to begin to reduce emissions. Sequestration will not be effective unless reservoir leak rates are significantly less than 1%. There must be rigorous monitoring protocols in place to ensure sequestration projects meet regulatory and environmental goals. Monitoring for CO2 leakage directly is difficult because of the large background levels and variability of CO2 in the atmosphere. Using tracers to tag the sequestered CO2 can mitigate some of the difficulties of direct measurement but a tracer monitoring network and the levels of tagging need to be carefully designed. Simple diffusion and dispersion models are used to predict the surface and atmospheric concentrations that would be seen by a network monitoring a sequestration site. Levels of tracer necessary to detect leaks from 0.01 to 1% are presented and suggestions for effective monitoring and protection of global tracer utility are presented.

  13. FTIR instrumentation to monitor vapors from Shuttle tile waterproofing materials

    Science.gov (United States)

    Mattson, C. B.; Schwindt, C. J.

    1995-11-01

    The Space Shuttle Thermal Protection System (TPS) tiles and blankets are waterproofed using DimethylEthoxySilane (DMEX) in the Orbiter Processing Facilities (OPF). DMES has a Threshold Limit Value (TLV) for exposure of personnel to vapor concentration in air of 0.5 ppm. The OPF high bay cannot be opened for normal work after a waterproofing operation until the DMES concentration is verified by measurement to be below the TLV. On several occasions the high bay has been kept closed for up to 8 hours following waterproofing operations due to high DMES measurements. In addition, the Miran 203 and Miran 1 BX infrared analyzers calibrated at different wavelengths gave different readings under the same conditions. There was reason to believe that some of the high DMES concentration readings were caused by interference form water and ethanol vapors. The Toxic Vapor Detection Laboratory (TVDL) was asked to test the existing DMES instruments and identify the best qualified instrument. In addition the TVDL was requested to develop instrumentation to ensure the OPF high bay could be opened safely as soon as possible after a waterproofing operation. A Fourier Transform Infrared (FTIR) spectrophotometer instrument developed for an earlier project was reprogrammed to measure DMES vapor along with ethanol, water, and several common solvent vapors. The FTIR was then used to perform a series of laboratory and field tests to evaluate the performance of the single wavelength IR instruments in use. The results demonstrated that the single wavelength IR instruments did respond to ethanol and water vapors, more or less depending on the analytical IR wavelength selected. The FTIR was able to separate the responses to DMES, water and ethanol, and give consistent readings for the DMES vapor concentration. The FTIR was then deployed to the OPF to monitor real waterproofing operations. The FTIR was also used to measure the time for DMES to evaporate from TPS tile under a range of humidity

  14. Cross-borehole ERT monitoring of a tracer injection into chlorinated-solvent contaminated fractured mudstone

    Science.gov (United States)

    Robinson, J.; Slater, L. D.; Johnson, T. C.; Day-Lewis, F. D.; Imbrigiotta, T. E.; Johnson, C. D.; Lacombe, P.; Lane, J. W., Jr.; Ntarlagiannis, D.; Shapiro, A. M.; Tiedeman, C. R.

    2014-12-01

    There is a need to monitor remedial injections in contaminated fractured rock to determine if targeted areas have been reached and to monitor treatment effectiveness. While detailed information can be obtained at boreholes, these locations are limited; determining connectivity in fracture networks is difficult and borehole monitoring locations may miss the injection entirely. The primary and secondary domains in fractured rock have hydraulic conductivities that differ by orders of magnitude such that tracer injections commonly have rapid breakthrough followed by extended tailings. Often, it is presumed that the tracer is transported into dead-end pore spaces or unknown inter-connected networks and/or sorbed into the primary porosity. Cross-borehole electrical resistivity tomography (ERT), guided by information from borehole geophysical logging and hydraulic testing, has the potential to monitor the fate of tracer injections between borehole locations. ERT has been under-exploited in fractured rock due to: (1) a lack of available 3D codes, (2) a lack of computing resources to accommodate a large number of model parameters, and (3) limitations of regularization constraints used in ERT modeling for representing fractured rock settings along with a full understanding of these constraints. Recognizing numerous advances in ERT imaging and building on our previous studies, we present results from a field-scale ERT experiment in fractured rock. We use ERT to monitor a conductive tracer injection in a fractured mudstone at the Naval Air Warfare Center (NAWC) in New Jersey. A custom-built electrode array included inflatable bladders to isolate fractures within each borehole and allowed for discrete water sampling and injection. By injecting the tracer in pulses and collecting 3D ERT measurements following each pulse, we were able to (1) avoid rapid breakthrough and large dilution rates and thus maintain a high conductivity contrast, and (2) characterize ambient flow by

  15. LC-MS solvent composition monitoring and chromatography alignment using mobile phase tracer molecules.

    Science.gov (United States)

    Chen, Sharon S; Aebersold, Ruedi

    2005-12-27

    In the field of proteomics, reproducible liquid chromatographic description of analytes is often a key element for the differentiation or identification of proteins or peptides for clinical or biological research projects. However, analyte identification by retention time can be problematic in proteomics where lack of standardization can result in significantly different chromatography for the same analytes analyzed on different machines. Here we present a novel method of monitoring the mobile phase gradient of LC-MS/MS analyses by monitoring the ion current signal intensities of tracer molecules dissolved in the mobile phase solvents. The tracers' ion current signal intensities chronicled gradient fluctuations, did not adversely affect the number or quality of CID-based sequence identifications, and had lower run-to-run variance when compared to retention time.

  16. Study with liquid and steam tracers at the Tejamaniles area, Los Azufres, Mich., geothermal field; Estudio con trazadores de liquido y vapor en el area Tejamaniles del campo geotermico de Los Azufres, Mich.

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, Eduardo R. [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)]. E-mail: iglesias@iie.org.mx; Flores Armenta, Magaly [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico); Torres, Rodolfo J. [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico); Ramirez Montes, Miguel [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico); Reyes Picasso, Neftali [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico); Reyes Delgado, Lisette [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)

    2011-01-15

    The Mexican Federal Commission for Electricity injects brines produced by nearby geothermal wells into well Az-08, located in the Tejamaniles area, in the southwestern portion of Los Azufres, Mich., geothermal field. The main goals of this study are to determine whether or not the injected fluid recharges nine producing wells in the area, and if so, to estimate the fraction of the injected fluid recharging each producing well. Five of the selected wells produce mixes of liquid and steam and the rest produce only steam. For this reason, we designed this study with simultaneous injections of liquid- and steam-tracers. The nine selected producing wells detected the steam-tracer, and the five wells producing mixes detected the liquid-phase tracer. The residence curves of both tracers present a series of peaks reflecting the known fractured nature of the reservoir. The results show the feeding areas of the nine selected wells are recharged by the fluid injected into well Az-08. When this paper was written, the arrival of steam-tracers in all wells was completed, but the wells producing mixes of liquid and steam continued to record the arrival of the liquid-tracer. Until 407 days after injecting the tracer, the total percentage recovery of liquid phase tracer in the five wells producing mixes of liquid and steam was 3.5032%. The arrival of the steam tracer ended in all nine wells 205 days after the tracer was injected, with an overall recovery rate of 2.1553 x 10-2%. The recovery rates imply the recharge rates of the monitored wells by the injector Az-08 are modest, but it appears the amounts of the recovered liquid-phase tracer will increase significantly. The modest recovery rates suggest most of the fluid injected into the well Az-08 disperses in the reservoir, contributing to recharge and maintaining the pressure. Results reveal that: (i) the injected fluid is heated at depths from 700 to over 1000 m, where it boils and rises to reach the feeding areas of the

  17. REAL-TIME TRACER MONITORING OF RESERVOIR STIMULATION PROCEDURES VIA ELECTRONIC WIRELINE AND TELEMETRY DATA TRANSMISSION

    Energy Technology Data Exchange (ETDEWEB)

    George L. Scott III

    2005-01-01

    Finalized Phase 2-3 project work has field-proven two separate real-time reservoir processes that were co-developed via funding by the National Energy Technology Laboratory (NETL). Both technologies are presently patented in the United States and select foreign markets; a downhole-commingled reservoir stimulation procedure and a real-time tracer-logged fracturing diagnostic system. Phase 2 and early Phase 3 project work included the research, development and well testing of a U.S. patented gamma tracer fracturing diagnostic system. This stimulation logging process was successfully field-demonstrated; real-time tracer measurement of fracture height while fracturing was accomplished and proven technically possible. However, after the initial well tests, there were several licensing issues that developed between service providers that restricted and minimized Realtimezone's (RTZ) ability to field-test the real-time gamma diagnostic system as was originally outlined for this project. Said restrictions were encountered after when one major provider agreed to license their gamma logging tools to another. Both of these companies previously promised contributory support toward Realtimezone's DE-FC26-99FT40129 project work, however, actual support was less than desired when newly-licensed wireline gamma logging tools from one company were converted by the other from electric wireline into slickline, batter-powered ''memory'' tools for post-stimulation logging purposes. Unfortunately, the converted post-fracture measurement memory tools have no applications in experimentally monitoring real-time movement of tracers in the reservoir concurrent with the fracturing treatment. RTZ subsequently worked with other tracer gamma-logging tool companies for basic gamma logging services, but with lessened results due to lack of multiple-isotope detection capability. In addition to real-time logging system development and well testing, final Phase 2 and

  18. Real-time monitoring of the penetration of amphiphilic acrylate copolymer in leather using a fluorescent copolymer as tracer.

    Science.gov (United States)

    Du, Jin-Xia; Shi, Lu; Peng, Bi-Yu

    2015-12-01

    A fluorescent tracer, poly (acrylic-co-stearyl acrylate-co-3-acryloyl fluorescein) [poly (AA-co-SA-co-Ac-Flu)], used for real-time monitoring the penetration of amphiphilic acrylate copolymer, poly (acrylic-co-stearyl acrylate) [poly (AA-co-SA)], in leather was synthesized by radical polymerization of acrylic, stearyl acrylate and fluorescent monomer, 3-acryloyl fluorescein (Ac-Flu). The structure, molecular weight, introduced fluorescent group content and fluorescent characteristics of the fluorescent tracer and target copolymer, amphiphilic acrylate copolymer, were also characterized. The results show that the tracer presents the similar structural characteristics to the target and enough fluorescence intensity with 1.68 wt % of the fluorescent monomer introduced amount. The vertical section of the leather treated with the target copolymer mixing with 7% of the tracer exhibits evident fluorescence, and the change of fluorescence intensity along with the vertical section with treating time increasing can reflect the penetration depth of the target copolymer. The introduction of the fluorescent group in polymer structure through copolymerization with a limited amount of fluorescent monomer, Ac-Flu, is an effective way to make a tracer to monitor the penetration of the target in leather, which provides a new thought for the penetration research of syntans such as vinyl copolymer materials in leather manufacture.

  19. Results of Vapor Space Monitoring of Flammable Gas Watch List Tanks

    Energy Technology Data Exchange (ETDEWEB)

    MCCAIN, D.J.

    2000-09-27

    This report documents the measurement of headspace gas concentrations and monitoring results from the Hanford tanks that have continuous flammable gas monitoring. The systems used to monitor the tanks are Standard Hydrogen Monitoring Systems. Further characterization of the tank off-gases was done with Gas Characterization systems and vapor grab samples. The background concentrations of all tanks are below the action level of 6250 ppm. Other information which can be derived from the measurements (such as generation rate, released rate, and ventilation rate) is also discussed.

  20. High Prf Metal Vapor Laser Active Media For Visual And Optical Monitoring

    Science.gov (United States)

    Torgaev, S. N.; Trigub, M. V.; Evtushenko, G. S.; Evtushenko, T. G.

    2016-01-01

    In this paper the feasibility of using metal vapor lasers for visual and optical monitoring of fast processes is discussed. The theoretical calculations consistent with the experimental study have been performed. The possibility of visualizing objects with pulse repetition frequency of the brightness amplifier up to 60 kHz has been demonstrated. The visualization results of the corona discharge are also given.

  1. Developments toward a low-cost approach for long-term, unattended vapor intrusion monitoring.

    Science.gov (United States)

    Patel, Sanjay V; Tolley, William K

    2014-08-07

    There are over 450 000 sites contaminated by chemicals in the US. This large number of contaminated sites and the speed of subsurface migration of chemicals pose considerable risk to nearby residences and commercial buildings. The high costs for monitoring around these sites stem from the labor involved in placing and replacing the passive sorbent vapor samplers and the resultant laboratory analysis. This monitoring produces sparse data sets that do not track temporal changes well. To substantially reduce costs and better track exposures, less costly, unattended systems for monitoring soil gases and vapor intrusion into homes and businesses are desirable to aid in the remediation of contaminated sites. This paper describes progress toward the development of an inexpensive system specifically for monitoring vapor intrusion; the system can operate repeatedly without user intervention with low detection limits (1 × 10(-9), or 1 part-per-billion). Targeted analytes include chlorinated hydrocarbons (dichloroethylene, trichloroethane, trichloroethylene, and perchloroethylene) and benzene. The system consists of a trap-and-purge preconcentrator for vapor collection in conjunction with a compact gas chromatography instrument to separate individual compounds. Chemical detection is accomplished with an array of chemicapacitors and a metal-oxide semiconductor combustibles sensor. Both the preconcentrator and the chromatography column are resistively heated. All components are compatible with ambient air, which serves as the carrier gas for the gas chromatography and detectors.

  2. Development of Radon-222 as Natural Tracer for Monitoring the Remediation of NAPL in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Brian M. Davis; Lewis Semprini; Jonathan Istok

    2003-02-27

    Naturally occurring 222-radon in ground water can potentially be used as an in situ partitioning tracer to characterize dense nonaqueous phase liquid (DNAPL) saturations. The static method involves comparing radon concentrations in water samples from DNAPL-contaminated and non-contaminated portions of an aquifer. During a push-pull test, a known volume of test solution (radon-free water containing a conservation tracer) is first injected (''pushed'') into a well; flow is then reversed and the test solution/groundwater mixture is extracted (''pulled'') from the same well. In the presence of NAPL radon transport is retarded relative to the conservative tracer. Assuming linear equilibrium partitioning, retardation factors for radon can be used to estimate NAPL saturations.The utility of this methodology was evaluated in laboratory and field settings.

  3. Detection of tracer materials in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, A.; Lovelock, J.E.

    1981-12-08

    As oxygen is an electron absorber it is desirable, when monitoring an atmospheric flow for the presence of tracer materials capable of detection in an electron capture detector, to remove the oxygen from the flow to the detector. The invention introduces a hydrogen supply directly into the atmospheric flow to allow the hydrogen to combine catalytically with the oxygen content of the flow to form water or water vapor. The thus formed water or water vapor is extracted from the flow proceeding to the detector. The reaction can occur within a palladium or palladium alloy conduit forming a part of the flow path to the detector.

  4. In-Flight Performance of the Water Vapor Monitor Onboard the Sofia Observatory

    Science.gov (United States)

    Roellig, Thomas L.; Yuen, Lunming; Sisson, David; Hang, Richard

    2012-01-01

    NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) airborne observatory flies in a modified B747-SP aircraft in the lower stratosphere above more than 99.9% of the Earth's water vapor. As low as this residual water vapor is, it will still affect SOFIA's infrared and sub-millimeter astronomical observations. As a result, a heterodyne instrument has been developed to observe the strength and shape of the 1830Hz rotational line of water, allowing measurements of the integrated water vapor overburden in flight. In order to be useful in correcting the astronomical signals, the required measured precipitable water vapor accuracy must be 2 microns or better, 3 sigma, and measured at least once a minute. The Water Vapor Monitor has flown 22 times during the SOFIA Early Science shared-risk period. The instrument water vapor overburden data obtained were then compared with concurrent data from GOES-V satellites to perform a preliminary calibration of the measurements. This presentation will cover the.results of these flights. The final flight calibration necessary to reach the required accuracy will await subsequent flights following the SOFIA observatory upgrade that is taking place during the spring and summer of 2012.

  5. Monitoring laboratory-scale bioventing using synchronous scan fluorescence spectroscopy: analysis of the vapor phase.

    Science.gov (United States)

    Bachman, J; Kanan, S M; Patterson, H H

    2001-01-01

    Bioventing is an improved method of soil remediation that is being used with increasing frequency. In this paper, we refine techniques to measure the progress of petroleum hydrocarbon decomposition by monitoring vapor phase composition with synchronous scan fluorescence spectroscopy (SSFS). Analysis of the vapor phase has advantages compared to standard extraction techniques that require extensive sample handling and clean up. For comparison, hydrocarbon contamination in the soil was measured by analysis of Soxhlet extractions with gas chromatography-mass spectrometry (GC-MS). Comparison of the GC-MS and SSFS data showed that changes in hydrocarbon composition measured in the vapor phase provide an accurate measure of decomposition reactions taking place in the soil.

  6. REAL-TIME TRACER MONITORING OF RESERVOIR STIMULATION PROCEDURES VIA ELECTRONIC WIRELINE AND TELEMETRY DATA TRANSMISSION

    Energy Technology Data Exchange (ETDEWEB)

    George Scott III

    2003-08-01

    Ongoing Phase 2-3 work comprises the final development and field-testing of two complementary real-time reservoir technologies; a stimulation process and a tracer fracturing diagnostic system. Initial DE-FC26-99FT40129 project work included research, development, and testing of the patented gamma tracer fracturing diagnostic system. This process was field-proven to be technically useful in providing tracer measurement of fracture height while fracturing; however, technical licensing restrictions blocked Realtimezone from fully field-testing this real-time gamma diagnostic system, as originally planned. Said restrictions were encountered during Phase 2 field test work as result of licensing limitations and potential conflicts between service companies participating in project work, as related to their gamma tracer logging tool technology. Phase 3 work principally demonstrated field-testing of Realtimezone (RTZ) and NETL's Downhole-mixed Reservoir Stimulation process. Early on, the simplicity of and success of downhole-mixing was evident from well tests, which were made commercially productive. A downhole-mixed acid stimulation process was tested successfully and is currently commercially used in Canada. The fourth well test was aborted due to well bore conditions, and an alternate test project is scheduled April, 2004. Realtimezone continues to effectuate ongoing patent protection in the United States and foreign markets. In 2002, Realtimezone and the NETL licensed their United States patent to Halliburton Energy Services (HES). Additional licensing arrangements with other industry companies are anticipated in 2004-2005. Ongoing Phase 2 and Phase 3 field-testing continues to confirm applications of both real-time technologies. Technical data transfer to industry is ongoing via Internet tech-transfer and various industry presentations and publications including Society of Petroleum Engineers. These real-time enhanced stimulation procedures should significantly

  7. Tracer Tests and Field Monitoring of In situ Bioreduction of Cr(VI) Bioreduction at the Hanford 100H Site

    Science.gov (United States)

    Long, P. E.; Newcomer, D. R.; Resch, C. T.; Cantrell, K.; Faybishenko, B.; Hazen, T. C.; Brodie, E.; Joyner, D.; Borglin, S.; Conrad, M.; Tokunaga, T.; Wan, J.; Hubbard, S.; Williams, K. H.; Peterson, J. E.; Firestone, M.; Andersen, G.; Desantis, T.; Hanlon, J.; Willett, A.; Koenigsberg, S.

    2006-05-01

    Tracer tests and field monitoring before, during, and after bio-immobilization of Cr(VI) in groundwater at the Hanford 100H field site have provided key data constraining the geohydrology and biogeochemistry of field- scale bioreduction. A slow release polylactate, Hydrogen Release Compound (HRC), was used to stimulate the in situ bioreduction and removal of Cr(VI) from groundwater. Monitoring included an extensive suite of field and laboratory techniques, as well as five Br-tracer injection tests and four pumping tests. To minimize drilling costs, a three-well system (injection well and upgradient and downgradient monitoring wells) was used for conducting the in situ biostimulation and monitoring. Pre-biostimulation Br-tracer tests demonstrated that low-flow pumping (1.2 to 2.5 l/min) on the down-gradient well was required to ensure capture of groundwater flow lines passing through the injection well (5 m from the downgradient pumping well). Detailed Br breakthrough curves were obtained using field-deployed Br ion-selective electrodes (Instrumentation Northwest, Inc.). We also used a multi-parameter flow cell (Hydrolab H2O Multiprobe) to collect hourly data on temperature, pH, redox potential, electrical conductivity, and dissolved oxygen (DO). Field measurements were used to enable repeat groundwater sampling by pumping through specially designed borehole water samplers. Following the HRC injection, the data demonstrated the temporal relationship between the Br arrival and onset of reducing conditions induced by the injection. For example, redox potential decreased from +240 to -130 mV while conductivity changed from ~510 μS/cm to ~850 μS/cm along with a complete removal of DO and a drop in pH. These changes occurred concomitantly with more than a 2- order of magnitude increase in microbial cell numbers. The pore-water conductivity changes were used to constrain interpretation of the results of cross-borehole radar tomography conducted prior to and after the

  8. Fingerprinting Captured CO2 Using Natural Tracers for CCS Monitoring and Verification

    Science.gov (United States)

    Flude, S.; Gilfillan, S.; Johnson, G.; Gyore, D.; Haszeldine, S.; Stuart, F. M.

    2015-12-01

    In the long term, captured CO2 will most likely be stored in large saline formations and it is highly likely that CO2 from multiple operators will be injected into a single saline formation. Understanding CO2 behaviour within the reservoir is vital for making operational decisions and often uses geochemical techniques. Furthermore, in the event of a CO2 leak, being able to identify the owner of the CO2 is of vital importance in terms of liability and remediation. Addition of geochemical tracers to the CO2 stream is an effective way of tagging the CO2 from different operators, but may become prohibitively expensive at large scale storage sites. Here we present results from a project assessing whether the natural isotopic composition (C, O and noble gas isotopes) of captured CO2 is sufficient to distinguish CO2 captured using different technologies and from different fuel sources from each other and from likely baseline conditions. Results include analytical measurements of CO2 sampled from a number of different CO2 capture plants and a comprehensive literature review of the known and hypothetical isotopic compositions of captured CO2 and baseline conditions. Key findings from the literature review suggest that the carbon isotope composition will be most strongly controlled by that of the feedstock, but significant fractionation is possible during the capture process; oxygen isotopes are likely to be controlled by the isotopic composition of any water used in either the industrial process or the capture technology; and noble gases concentrations will likely be controlled by the capture technique employed. Preliminary analytical results are in agreement with these predictions. Comparison with summaries of likely storage reservoir baseline data and shallow or surface leakage reservoir baseline data suggests that C-isotopes are likely to be valuable tracers of CO2 in the storage reservoir, while noble gases may be particularly valuable as tracers of potential leakage.

  9. Measuring Vapors To Monitor the State of Cure of a Resin

    Science.gov (United States)

    Cramer, Elliott; Perey, Daniel F.; Yost, William T.

    2006-01-01

    A proposed noninvasive method of monitoring the cure path and the state of cure of an epoxy or other resin involves measurement of the concentration( s) of one or more compound(s) in the vaporous effluent emitted during the curing process. The method is based on the following general ideas: (1) The concentrations of the effluent compounds in the vicinity of the curing resin are approximately proportional to the instantaneous rate of curing. (2) As curing proceeds at a given temperature, subsequent decreases in the concentrations are indicative of approaching completion of cure; that is, the lower are the concentrations, the more nearly complete is the cure.

  10. Near surface soil vapor clusters for monitoring emissions of volatile organic compounds from soils.

    Science.gov (United States)

    Ergas, S J; Hinlein, E S; Reyes, P O; Ostendorf, D W; Tehrany, J P

    2000-01-01

    The overall objective of this research was to develop and test a method of determining emission rates of volatile organic compounds (VOCs) and other gases from soil surfaces. Soil vapor clusters (SVCs) were designed as a low dead volume, robust sampling system to obtain vertically resolved profiles of soil gas contaminant concentrations in the near surface zone. The concentration profiles, when combined with a mathematical model of porous media mass transport, were used to calculate the contaminant flux from the soil surface. Initial experiments were conducted using a mesoscale soil remediation system under a range of experimental conditions. Helium was used as a tracer and trichloroethene was used as a model VOC. Flux estimations using the SVCs were within 25% of independent surface flux estimates and were comparable to measurements made using a surface isolation flux chamber (SIFC). In addition, method detection limits for the SVC were an order of magnitude lower than detection limits with the SIFC. Field trials, conducted with the SVCs at a bioventing site, indicated that the SVC method could be easily used in the field to estimate fugitive VOC emission rates. Major advantages of the SVC method were its low detection limits, lack of required auxiliary equipment, and ability to obtain real-time estimates of fugitive VOC emission rates.

  11. Atmospheric water vapor monitoring from local GNSS networks: comparisons of GNSS data adjustment strategies

    Science.gov (United States)

    Capponi, Martina; Fermi, Alessandro; Monti Guarnieri, Andrea; Realini, Eugenio; Venuti, Giovanna

    2016-04-01

    Since many years GNSS has been regarded by the meteorological community as one of the systems for atmospheric water vapor remote sensing. Time series of GNSS wet delays are estimated as by-products of accurate positioning. Their assimilation into numerical weather prediction (NWP) models is being investigated at both research and operational levels, although typically at coarse space resolutions (e.g. few tens of km). A dedicated use of this system for water vapor monitoring at higher resolutions is still under investigation. Ad hoc networks have been designed and implemented to collect data at a high spatial resolution (station inter-distances of 1-10 km), to have an insight into the spatial distribution of GNSS derived wet delays and/or into the impact of such information on high resolution NWP models. Within this research framework the paper reports the comparisons carried out between ZWD time series obtained from the data collected by an Italian and a Japanese dense networks of permanent geodetic GNSS receivers. Tropospheric delays have been estimated by applying different data adjustment strategies: relative positioning and PPP (precise point positioning). For this last strategy two different solutions have been analyzed and compared: the Bernese software batch solution, and the RTNet software Kalman filter solution. Assessment of the results were performed against IGS GNSS delays as well as by comparison with radiosonde-derived precipitable water vapor (PWV).

  12. Monitoring the water vapor isotopic composition in the temperate North Atlantic

    Science.gov (United States)

    Sveinbjörnsdottir, Arny E.; Steen-Larsen, Hans Christian; Jonsson, Thorsteinn; Johnsen, Sigfus J.

    2013-04-01

    Water stable isotopes have during many decades been used as climate proxies and indicators for variations in the hydrological cycle. However we are to a great extent still using simple empirical relationships without any deeper theoretical understanding. In order to properly relate changes in the climate and hydrological cycle to changes in the observed stable water isotopic signal we must understand the underlying physical processes. Furthermore it is a challenge for General Climate Models to adequately represent the isotopes in the hydrological cycle because of lack of in-situ measurements of the atmospheric water-vapor composition in the source regions. During the fall of 2010 we installed an autonomous water vapor spectroscopy laser (from Los Gatos Research) in a lighthouse on the South Coast of Iceland (63.83 N 21.47W) with the plan to be operational for several years. The purpose of this installation was through monitoring of the water vapor isotopic composition to understand the physical processes governing the isotopic composition of the water vapor evaporated from the ocean as well as the processes of mixing between the free troposphere and marine boundary layer. Because of the remoteness of the monitoring site and simple topography we are able to isolate the 'fingerprint' on the isotopic signal in the water vapor from respectively the ocean and the interior highland leading to a near perfect case-study area. Using back-trajectories we find a strong influence of the origin of the air masses on the measured isotopic composition. The mixing of the marine-boundary layer is found to strongly influence the measured isotopic composition. The second order isotopic parameter, d-excess, is contrary to theory and previous observations found not to depend on the relative humidity. However we do find a good correlation between the d-excess and the measured isotopic composition. We speculate that the lack of correlation between d-excess and relative humidity can be

  13. Hydrologic Process Regularization for Improved Geoelectrical Monitoring of a Lab-Scale Saline Tracer Experiment

    Science.gov (United States)

    Oware, E. K.; Moysey, S. M.

    2016-12-01

    Regularization stabilizes the geophysical imaging problem resulting from sparse and noisy measurements that render solutions unstable and non-unique. Conventional regularization constraints are, however, independent of the physics of the underlying process and often produce smoothed-out tomograms with mass underestimation. Cascaded time-lapse (CTL) is a widely used reconstruction technique for monitoring wherein a tomogram obtained from the background dataset is employed as starting model for the inversion of subsequent time-lapse datasets. In contrast, a proper orthogonal decomposition (POD)-constrained inversion framework enforces physics-based regularization based upon prior understanding of the expected evolution of state variables. The physics-based constraints are represented in the form of POD basis vectors. The basis vectors are constructed from numerically generated training images (TIs) that mimic the desired process. The target can be reconstructed from a small number of selected basis vectors, hence, there is a reduction in the number of inversion parameters compared to the full dimensional space. The inversion involves finding the optimal combination of the selected basis vectors conditioned on the geophysical measurements. We apply the algorithm to 2-D lab-scale saline transport experiments with electrical resistivity (ER) monitoring. We consider two transport scenarios with one and two mass injection points evolving into unimodal and bimodal plume morphologies, respectively. The unimodal plume is consistent with the assumptions underlying the generation of the TIs, whereas bimodality in plume morphology was not conceptualized. We compare difference tomograms retrieved from POD with those obtained from CTL. Qualitative comparisons of the difference tomograms with images of their corresponding dye plumes suggest that POD recovered more compact plumes in contrast to those of CTL. While mass recovery generally deteriorated with increasing number of time

  14. Monitoring the variability of precipitable water vapor over the Klang Valley, Malaysia during flash flood

    Science.gov (United States)

    Suparta, W.; Rahman, R.; Singh, M. S. J.

    2014-06-01

    Klang Valley is a focal area of Malaysian economic and business activities where the local weather condition is very important to maintain its reputation. Heavy rainfalls for more than an hour were reported up to 40 mm in September 2013 and 35 mm in October 2013. Both events are monitored as the first and second cases of flash flood, respectively. Based on these cases, we investigate the water vapor, rainfall, surface meteorological data (surface pressure, relative humidity, and temperature) and river water level. The precipitable water vapor (PWV) derived from Global Positioning System (GPS) is used to indicate the impact of flash flood on the rainfall. We found that PWV was dropped 4 mm in 2 hours before rainfall reached to 40 mm and dropped 3 mm in 3 hours before 35 mm of rainfall in respective cases. Variation of PWV was higher in September case compared to October case of about 2 mm. We suggest the rainfall phenomena can disturb the GPS propagation and therefore, the impact of PWV before, during and after the flash flood event at three selected GPS stations in Klang Valley is investigated for possible mitigation in the future.

  15. Monitoring and Prediction of Precipitable Water Vapor using GPS data in Turkey

    Science.gov (United States)

    Ansari, Kutubuddin; Althuwaynee, Omar F.; Corumluoglu, Ozsen

    2016-12-01

    Although Global Positioning System (GPS) primarily provide accurate estimates of position, velocity and time of the receiver, as the signals pass through the atmoshphere carrying its signatures, thus offers opportunities for atmoshpheric applications. Precipitable water vapor (PWV) is a vital component of the atmosphere and significantly influences atmospheric processes like rainfall and atmospheric temperature. The developing networks of continuously operating GPS can be used to efficiently estimate PWV. The Turkish Permanent GPS Network (TPGN) is employed to monitor PWV information in Turkey. This work primarily aims to derive long-term data of PWV by using atmospheric path delays observed through continuously operating TPGN from November 2014 to October 2015. A least square mathematical approach was then applied to establish the relation of the observed PWV to rainfall and temperature. The modeled PWV was correlated with PWV estimated from GPS data, with an average correlation of 67.10 %-88.60 %. The estimated root mean square error (RMSE) varied from 2.840 to 6.380, with an average of 4.697. Finally, data of TPGN, rainfall, and temperature were obtained for less than 2 months (November 2015 to December 2015) and assessed to validate the mathematical model. This study provides a basis for determining PWV by using rainfall and temperature data.

  16. Investigations of high mobility single crystal chemical vapor deposition diamond for radiotherapy photon beam monitoring

    Science.gov (United States)

    Tromson, D.; Descamps, C.; Tranchant, N.; Bergonzo, P.; Nesladek, M.; Isambert, A.

    2008-03-01

    The intrinsic properties of diamond make this material theoretically very suitable for applications in medical physics. Until now ionization chambers have been fabricated from natural stones and are commercialized by PTW, but their fairly high costs and long delivery times have often limited their use in hospital. The properties of commercialized intrinsic polycrystalline diamond were investigated in the past by many groups. The results were not completely satisfactory due to the nature of the polycrystalline material itself. In contrast, the recent progresses in the growth of high mobility single crystal synthetic diamonds prepared by chemical vapor deposition (CVD) technique offer new alternatives. In the framework of the MAESTRO project (Methods and Advanced Treatments and Simulations for Radio Oncology), the CEA-LIST is studying the potentialities of synthetic diamond for new techniques of irradiation such as intensity modulated radiation therapy. In this paper, we present the growth and characteristics of single crystal diamond prepared at CEA-LIST in the framework of the NoRHDia project (Novel Radiation Hard CVD Diamond Detector for Hadrons Physics), as well as the investigations of high mobility single crystal CVD diamond for radiotherapy photon beam monitoring: dosimetric analysis performed with the single crystal diamond detector in terms of stability and repeatability of the response signal, signal to noise ratio, response speed, linearity of the signal versus the absorbed dose, and dose rate. The measurements performed with photon beams using radiotherapy facilities demonstrate that single crystal CVD diamond is a good alternative for air ionization chambers for beam quality control.

  17. Technical Note: Novel method for water vapor monitoring using wireless communication networks measurements

    Science.gov (United States)

    David, N.; Alpert, P.; Messer, H.

    2008-06-01

    We propose a new technique that overcomes the obstacles of the existing methods for monitoring near-surface water vapor, by estimating humidity from data collected through existing wireless communication networks. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, the proposed method can provide moisture observations at high temporal and spatial resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. We present results from real-data measurements taken from two microwave links used in a backhaul cellular network that show excellent correlation to surface station humidity measurements. The measurements were taken daily in two sites, one in northern Israel (28 measurements), the other in central Israel (29 measurements).The correlation of the microwave link measurements to those of the humidity gauges were 0.9 and 0.82 for the north and central sites, respectively. The RMSE were 20.8% and 33.1% for the northern and central site measurements, respectively.

  18. 75 FR 64309 - Components for Evaluation of Direct-Reading Monitors for Gases and Vapors and Addendum

    Science.gov (United States)

    2010-10-19

    ...The National Institute for Occupational Safety and Health (NIOSH) of the Centers for Disease Control and Prevention (CDC) announces the availability of the following draft publication for public comment. The document and its addendum are entitled, respectively, ``Components for Evaluation of Direct-Reading Monitors for Gases and Vapors'' and ``Addendum to Components for Evaluation of Direct-Reading Monitors for Gases and Vapors: Hazard Detection in First Responder Environments.'' The draft documents and instructions for submitting comments can be found at: http://www.cdc.gov/niosh/docket/ review/docket220. The document expands the 1995 method development and evaluation experimental testing methods to direct-reading monitors for gases and vapors. These Components are provided for laboratory users, consensus standard setting bodies, and manufacturers of direct-reading instrumentation and are compatible with the Instrumentation, Systems, and Automation Society guidelines. The addendum to the document expands the applicability of the Components by presenting methods to be used in evaluating direct-reading monitors for hazard detection in First Responder environments. The 1995 document, entitled ``Guidelines for Air Sampling and Analytical Method Development and Evaluation,'' can be viewed at: http://www.cdc.gov/niosh/docs/ 95-117/. This guidance does not have the force and effect of the law.

  19. Environmental Tracers

    Directory of Open Access Journals (Sweden)

    Trevor Elliot

    2014-10-01

    Full Text Available Environmental tracers continue to provide an important tool for understanding the source, flow and mixing dynamics of water resource systems through their imprint on the system or their sensitivity to alteration within it. However, 60 years or so after the first isotopic tracer studies were applied to hydrology, the use of isotopes and other environmental tracers are still not routinely necessarily applied in hydrogeological and water resources investigations where appropriate. There is therefore a continuing need to promote their use for developing sustainable management policies for the protection of water resources and the aquatic environment. This Special Issue focuses on the robustness or fitness-for-purpose of the application and use of environmental tracers in addressing problems and opportunities scientifically, to promote their wider use and to address substantive issues of vulnerability, sustainability, and uncertainty in (groundwater resources systems and their management.

  20. Monitoring of saline tracer movement with vertically distributed self-potential measurements at the HOBE agricultural test site, Voulund, Denmark

    CERN Document Server

    Jougnot, Damien; Haarder, Eline B; Looms, Majken C

    2015-01-01

    The self-potential (SP) method is sensitive to water fluxes in saturated and partially saturated porous media, such as those associated with rainwater infiltration and groundwater recharge. We present a field-based study at the Voulund agricultural test site, Denmark, that is, to the best of our knowledge, the first to focus on the vertical self-potential distribution prior to and during a saline tracer test. A coupled hydrogeophysical modeling framework is used to simulate the SP response to precipitation and saline tracer infiltration. A layered hydrological model is first obtained by inverting dielectric and matric potential data. The resulting model that compares favorably with electrical resistance tomography models is subsequently used to predict the SP response. The electrokinetic contribution (caused by water fluxes in a charged porous soil) is modeled by an effective excess charge approach that considers both water saturation and pore water salinity. Our results suggest that the effective excess char...

  1. Study with a steam tracer in a zone near well Az-64, in the Los Azufres geothermal field, Mich.; Estudio con un trazador de vapor en la zona aledana al pozo Az-64, en el campo geotermico de Los Azufres, Mich.

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, Eduardo R. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: iglesias@iie.org.mx; Flores Armenta, Magaly; Quijano Leon, Jose Luis; Torres Rodriguez, Marco A. [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico); Torres, Rodolfo J.; Reyes Picasso, Neftali [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Sandoval Medina, Fernando [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)

    2009-01-15

    and 539 m from the injector. The results showed the six monitored wells are recharged from injection in Az-64 and quantified the corresponding recoveries as steam. Because only a steam-phase tracer was used, we were unable to determine liquid-recovery amounts. The work also allowed us to characterize relations between the permeability in the studied zone and the known distribution of faults. Some relationships were suggested unconsidered before. [Spanish] En el estudio con trazadores precedente a este, efectuado en la zona Maritaro-La Cumbre del campo geotermico de Los Azufres, Mich., se comprobo que la inyeccion en el pozo Az-15 recarga a un grupo de pozos situados a una distancia maxima del inyector de algo menos de 2000 m. Y se comprobo que la inyeccion en dicho pozo o bien no recarga a pozos situados a mas de 2300 m hacia el este, en las inmediaciones de la falla Laguna Verde, o lo hace muy lentamente en un largo periodo. Como es importante recargar la zona mencionada en ultimo termino, se decidio entonces explorar la posibilidad de recargarla desde el pozo Az-64, localizado en dicha area. Para ello se diseno el presente estudio. Se designaron seis pozos productores para monitorear el arribo del trazador. Debido a que todos estos pozos producen vapor (aunque varios producen tambien liquido), y por consideraciones economicas, se decidio utilizar en este caso un trazador de vapor solamente. Se utilizo hexafluoruro de azufre (SF6), un trazador utilizado con exito previamente en este campo. El 24 de octubre de 2006 se inyectaron 96.4 kg de SF6 en el pozo Az-64. El monitoreo de los pozos se realizo durante 156 dias a partir de esa fecha. El trazador se detecto en los seis pozos productores monitoreados. En todos los casos las formas de las curvas de residencia manifestaron claramente la naturaleza fracturada de la permeabilidad involucrada. En todos los casos las curvas de recuperacion del trazador indicaron claramente que la llegada del mismo se habia completado

  2. A new technique for monitoring the water vapor in the atmosphere

    Science.gov (United States)

    Black, H. D.; Eisner, A.

    1984-01-01

    In the correction of satellite Doppler data for tropospheric effects the precipitable water vapor (PWV) is inferred at the tracking site. The technique depends on: (1) an ephemeris for the satellite; (2) an analytic model for the refraction range effect that is good to a few centimeters; (3) Doppler data with noise level below 10 centimeters; and (4) a surface pressure/temperature measurement at the tracking site. The PWV is a by product of the computation necessary to correct the Doppler data for tropospheric effects. A formulation of the refraction integral minimizes the necessity for explicit water vapor, temperature and pressure profiles.

  3. Using Conventional Monitoring Wells to Collect Data Necessary to Understand Petroleum Vapor Intrusion (PVI)

    Science.gov (United States)

    Recent work has clearly established that the possibility for vapor intrusion of petroleum hydrocarbons is greatly reduced by aerobic biodegradation of the hydrocarbons in unsaturated soil. The rate and extent of aerobic biodegradation of benzene (or any other fuel hydrocarbon) in...

  4. Using Conventional Monitoring Wells to Collect Data Necessary to Understand Petroleum Vapor Intrusion (PVI)

    Science.gov (United States)

    Recent work has clearly established that the possibility for vapor intrusion of petroleum hydrocarbons is greatly reduced by aerobic biodegradation of the hydrocarbons in unsaturated soil. The rate and extent of aerobic biodegradation of benzene (or any other fuel hydrocarbon) in...

  5. Continuous monitoring of summer surface water vapor isotopic composition above the Greenland Ice Sheet

    Directory of Open Access Journals (Sweden)

    H. C. Steen-Larsen

    2013-05-01

    Full Text Available We present here surface water vapor isotopic measurements conducted from June to August 2010 at the NEEM (North Greenland Eemian Drilling Project camp, NW Greenland (77.45° N, 51.05° W, 2484 m a.s.l.. Measurements were conducted at 9 different heights from 0.1 m to 13.5 m above the snow surface using two different types of cavity-enhanced near-infrared absorption spectroscopy analyzers. For each instrument specific protocols were developed for calibration and drift corrections. The inter-comparison of corrected results from different instruments reveals excellent reproducibility, stability, and precision with a standard deviations of ~ 0.23‰ for δ18O and ~ 1.4‰ for δD. Diurnal and intraseasonal variations show strong relationships between changes in local surface humidity and water vapor isotopic composition, and with local and synoptic weather conditions. This variability probably results from the interplay between local moisture fluxes, linked with firn–air exchanges, boundary layer dynamics, and large-scale moisture advection. Particularly remarkable are several episodes characterized by high (> 40‰ surface water vapor deuterium excess. Air mass back-trajectory calculations from atmospheric analyses and water tagging in the LMDZiso (Laboratory of Meteorology Dynamics Zoom-isotopic atmospheric model reveal that these events are associated with predominant Arctic air mass origin. The analysis suggests that high deuterium excess levels are a result of strong kinetic fractionation during evaporation at the sea-ice margin.

  6. Study of liquid and steam tracers at the Maritaro - La Cumbre area of the Los Azufres geothermal field, Mich.; Estudio con trazadores de liquido y vapor en la zona Maritaro - La Cumbre del campo geotermico de Los Azufres, Mich.

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, Eduardo R [Instituto de Investigaciones Electricas, Cuernavaca, Morelos, (Mexico)]. E-mail: iglesias@iie.org.mx; Flores Armenta, Magaly; Quijano Leon, Jose Luis; Torres Rodriguez, Marco A [Comision Federal de Electricidad, Morelia, Michoacan (Mexico); Torres, Rodolfo J; Reyes Picasso, Neftali [Instituto de Investigaciones Electricas, Cuernavaca, Morelos, (Mexico)

    2008-01-15

    We ran two simultaneous tracer tests in the Maritaro-La Cumbre area of the Los Azufres geothermal field in Mexico. We wished to determine whether or not fluids injected in well Az-15 recharged the productive areas of six production wells and to estimate the fractions of injected fluid recovered in them, if any. Because only three of the wells produce water and all of them produce steam, two tracers were used, sulfur hexafluoride (SF{sub 6}) for the gas phase and 1,3,6 naphthalene trisulfonate (1,3,6-nts) for the liquid phase. All of the observation wells recorded SF{sub 6}, and the three water-producing wells recorded 1,3,6-nts, proving that fluids injected in well Az-15 do recharge the area of interest. When sampling was suspended, the three water-producing wells were still producing 1,3,6-nts at significant rates. The total recovery of 1,3,6-nts at wells Az-65D, Az-04 and Az-28, 279 days after injection when sampling was halted, were, respectively, 6.1%, 0.90% y 0.16%, for a total of 7.61%. We concluded that these quantities constitute the lower boundaries for the respective recovery factors. When sampling was halted, wells Az-65D, Az-66D and Az-30 were still producing some SF{sub 6} at lower rates, and the rest of the wells were no longer recording the gas phase tracer. The total recovery of SF{sub 6} at wells Az-65D, Az-04, Az-41, Az-30, Az-28 and Az-66D were, respectively, 4.82 e-02%, 1.37 e-03%, 1.48 e-03%, 6.38 e-04%, 1.38 e-03% y 4.31 e-04%, for a total of 5.35 e-02%. The liquid recharge occurred in orders of magnitude greater than the steam. [Spanish] Se efectuaron dos pruebas simultaneas en la zona Maritaro-La Cumbre del campo geotermico de Los Azufres, Mich., Mexico. Los objetivos de estas pruebas fueron determinar si la salmuera de desecho inyectada en el pozo Az-15 recarga las zonas de alimentacion de seis pozos productores designados por CFE, y estimar que fraccion de lo inyectado recarga dichos pozos productores. Debido a que solo tres de los pozos

  7. The novel technique of vapor pressure analysis to monitor the enzymatic degradation of PHB by HPLC chromatography.

    Science.gov (United States)

    Polyák, Péter; Rácz, Piroska; Rózsa, Péter; Nagy, Gergely N; Vértessy, Beáta G; Pukánszky, Béla

    2017-03-15

    A novel method was introduced for the quantitative determination of substances in aqueous solutions by using the evaporative light scattering (ELS) detector of a high performance liquid chromatograph (HPLC). The principle of the measurement is the different equilibrium vapor pressure of the solvent and the analyte resulting in decreasing evaporation rate, larger droplets and stronger signal with increasing concentration. The new technique based on vapor pressure analysis was validated with traditional UV-Vis detection carried out with a diode array detector (DAD). The new technique was used for monitoring the concentration of solutions obtained during the enzymatic degradation of poly(3-hydroxybutyrate) yielding the 3-hydroxybutyrate monomer as the product. The accuracy of the measurement allowed the determination of degradation kinetics as well. The results obtained with the two techniques showed excellent agreement at small concentrations. Deviations at larger concentrations were explained with the non-linear correlation between analyte concentration and detector signal and the linear regression used for calibration. Mathematical analysis of the method made possible the determination of the evaporation enthalpy of the analyte as well. The new approach is especially suitable for the quantitative analysis of compounds, which do not absorb in the detection range of the DAD detector or if their characteristic absorbance is close to the lower end of its wavelength range.

  8. Tracer tests and uncertainty propagation to design monitoring setups in view of pharmaceutical mass flow analyses in sewer systems.

    Science.gov (United States)

    Klepiszewski, Kai; Venditti, Silvia; Koehler, Christian

    2016-07-01

    The development of a strategic approach to manage pollution of surface waters with pharmaceutical residues is in centre of interest in Europe. In this context a lack of reliable standard procedures for sampling and subsequent assessment of pharmaceutical mass flows in the water cycle has been identified. Authoritative assessment of relevant substance concentrations and flows is essential for environmental risk assessments and reliable efficiency analysis of measures to reduce or avoid emissions of drugs to water systems. Accordingly, a detailed preparation of monitoring campaigns including an accuracy check for the sampling configuration provides important information on the reliability of the gathered data. It finally supports data analysis and interpretation for evaluations of the efficiency of measures as well as for cost benefit assessments. The precision of mass flow balances is expected to be particularly weak when substances with high short-term variations and rare upstream emissions are considered. This is especially true for substance flow analysis in sewers close to source because of expectable highly dynamic flow conditions and emission patterns of pollutants. The case study presented here focusses on the verification of a monitoring campaign in a hospital sewer in Luxembourg. The results highlight the importance for a priori accuracy checks and provide a blueprint for well-designed monitoring campaigns of pharmaceutical trace pollutants on the one hand. On the other hand, the study provides evidence that the defined and applied continuous flow proportional sampling procedure enables a representative monitoring of short-term peak loads of the x-ray contrast media iobitridol close to source. Copyright © 2016. Published by Elsevier Ltd.

  9. Water quality monitoring in a bathing area of Civitavecchia (Latium, Italy) using Chromophoric Dissolved Organic Matter (CDOM) as a tracer of faecal contamination

    Science.gov (United States)

    Madonia, Alice; Bonamano, Simone; Caruso, Gabriella; Stefani', Chiara; Consalvi, Natalizia; Piermattei, Viviana; Zappalà, Giuseppe; Marcelli, Marco

    2017-04-01

    Coastal urban bathing areas are often affected by events of faecal contamination, caused by the discharge of untreated wastewaters during the bathing season that can increase the risk for public health. Monitoring the quality of recreational waters is still closely linked to time-consuming seawater sampling and laboratory analysis, not allowing promptly management interventions. To face this issue, the European environmental policies strongly promote the development of coastal observing systems, above all in the Southern European Seas (SES). Chromophoric Dissolved Organic Matter (CDOM) has been increasingly used as a tracer of bacterial loads, since wastewaters are characterized by a large amount of organic compounds. The aim of this work was to study the relation between CDOM and Escherichia coli abundance, giving relevance to bacterial physiological state detected using both the standard culture method and the innovative fluorescent antibody technique. Attention has been paid also on the expression of extracellular enzymatic activity by the total microbial community to explore the role of bacteria in the decomposition processes of dissolved organic matter. Data were collected during summer 2015 and 2016 in a bathing area of Civitavecchia at increasing distances from the discharge point. The results confirm the usefulness of CDOM measurements as a proxy of faecal pollution in bathing areas. In this perspective, the low-cost stand-alone systems equipped with CDOM fluorescence sensors developed by the Laboratory of Experimental Oceanology and Marine Ecology (Tuscia University) (Marcelli et al., 2014) could allow the continous monitoring of water quality, increasing the capabilities of the Civitavecchia Coastal Environmental Monitoring System (C-CEMS) in the analysis of pollution events. Thanks to the integration of in situ fixed stations, high-resolution satellites imagery and numerical models, C-CEMS provides a management tool to support the stakeholders for timely

  10. Direct radioimmunoassay for estriol-16-glucuronide in urine for monitoring pregnancy and induction of ovulation. [Tritium tracer techniques

    Energy Technology Data Exchange (ETDEWEB)

    Haning, R.V. Jr.; Satin, K.P.; Lynskey, M.T.; Levin, R.M.; Speroff, L.

    1977-08-01

    Antibodies to estriol-16..cap alpha..-(..beta..-D-glucuronide) were raised in sheep with the use of keyhole limpet hemocyanin and bovine serum albumin conjugates of estriol-16..cap alpha..-(..beta..-D-glucuronide). A simple, rapid method is presented for direct radioimmunoassay of estriol-16..cap alpha..-(..beta..-D-glucuronide) in urine with dextran-coated charcoal used for separation of free from bound and deionized water used for dilutions. The method is thrifty in its use of reagents. The assay has been evaluated in the pregnancy range, and the sensitivity has been extended into the range necessary for monitoring induction of ovulation with pergonal.

  11. Monitoring radon emission anomalies at Stromboli Island as a tracer of eruptive events and “near field” earthquakes

    Directory of Open Access Journals (Sweden)

    Cigolini C.

    2012-04-01

    Full Text Available Radon emission from soil at Stromboli Island has been monitored since 2002 utilizing a network of 25 stations and exposing two kinds of detectors: E-PERM and calibrated track-etches (LR115. We present and discuss the data from 2002 to 2007, thus including the last two major eruptive cycles. Earthquake-volcano interactions were detected providing evidence that radon emissions are somehow related to the occurrence of regional earthquakes. Single deep earthquakes related to active subduction, such as Salina event (ML = 5.1 of May 5, 2004, may be capable of increasing the ascent of geothermal fluids due to the passage of seismic waves. In addition, we observed major eruptions at Stromboli were preceded by anomalies that occurred at three summit stations that reached values above 20000 Bq m−3 : this is considered an anomalous value and could be regarded, under particular environmental conditions, as a potential precursory signal of a change in volcanic activity.

  12. Practical silicon deposition rules derived from silane monitoring during plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Bartlome, Richard, E-mail: richard.bartlome@alumni.ethz.ch; De Wolf, Stefaan; Demaurex, Bénédicte; Ballif, Christophe [Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory, Rue de la Maladière 71b, 2000 Neuchâtel (Switzerland); Amanatides, Eleftherios; Mataras, Dimitrios [University of Patras, Department of Chemical Engineering, Plasma Technology Laboratory, P.O. Box 1407, 26504 Patras (Greece)

    2015-05-28

    We clarify the difference between the SiH{sub 4} consumption efficiency η and the SiH{sub 4} depletion fraction D, as measured in the pumping line and the actual reactor of an industrial plasma-enhanced chemical vapor deposition system. In the absence of significant polysilane and powder formation, η is proportional to the film growth rate. Above a certain powder formation threshold, any additional amount of SiH{sub 4} consumed translates into increased powder formation rather than into a faster growing Si film. In order to discuss a zero-dimensional analytical model and a two-dimensional numerical model, we measure η as a function of the radio frequency (RF) power density coupled into the plasma, the total gas flow rate, the input SiH{sub 4} concentration, and the reactor pressure. The adjunction of a small trimethylboron flow rate increases η and reduces the formation of powder, while the adjunction of a small disilane flow rate decreases η and favors the formation of powder. Unlike η, D is a location-dependent quantity. It is related to the SiH{sub 4} concentration in the plasma c{sub p}, and to the phase of the growing Si film, whether the substrate is glass or a c-Si wafer. In order to investigate transient effects due to the RF matching, the precoating of reactor walls, or the introduction of a purifier in the gas line, we measure the gas residence time and acquire time-resolved SiH{sub 4} density measurements throughout the ignition and the termination of a plasma.

  13. Comparison of semiquantitative fluorescence imaging and PET tracer uptake in mesothelioma models as a monitoring system for growth and therapeutic effects

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Yuriko [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, 263-8555 (Japan); Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, 260-8675 (Japan); Furukawa, Takako [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, 263-8555 (Japan); Biomedical Imaging Research Center, University of Fukui, Yoshida, Fukui, 910-1193 (Japan); Arano, Yasushi [Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, 260-8675 (Japan); Fujibayashi, Yasuhisa [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, 263-8555 (Japan); Biomedical Imaging Research Center, University of Fukui, Yoshida, Fukui, 910-1193 (Japan); Saga, Tsuneo [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, 263-8555 (Japan)

    2008-11-15

    Introduction: Various techniques are available for in vivo imaging, and precise understanding of their characteristics is essential for effective use of the imaging results. We established human mesothelioma cell lines expressing red fluorescent protein (RFP) and examined their fluorescence intensity and uptake of positron emission tomography (PET) tracer analogs to compare their characteristics and assess their usefulness in the evaluation of therapeutics. Method: A human mesothelioma cell line was stably transfected to express RFP. Fluorescence, cell number and protein amount were measured during cell growth and treatment with cytotoxic reagents. In in vivo experiments, RFP-expressing cells were injected subcutaneously or into the pleural cavity of nude mice, and fluorescence images were taken with or without pemetrexed treatment. The uptake of [{sup 3}H]3'-deoxy-3'-fluorothymidine ([{sup 3}H]FLT) and [{sup 14}C]2-fluoro-2-deoxy-D-glucose ([{sup 14}C]FDG) under treatment with the above reagents in vitro and in vivo were examined. Results: Strong correlation was observed between fluorescence intensity and total cell number with or without cytotoxic treatment. The uptake of [{sup 3}H]FLT and [{sup 14}C]FDG decreased rapidly after the initiation of treatment with actinomycin D or cycloheximide. When treated with pemetrexed, the uptake of [{sup 3}H]FLT temporarily increased. The cells formed subcutaneous and orthotopic tumors, with fluorescence intensity correlating with tumor volume. The correlation was sustained under pemetrexed treatment. The uptake of [{sup 3}H]FLT in vivo increased significantly early after pemetrexed treatment. Conclusion: Fluorescence imaging could be used to semiquantitatively monitor tumor size, whereas PET could be used to monitor tumor response to therapeutic treatments, and especially, FLT might be a good marker of the response to anti-folate chemotherapeutics.

  14. Tracer test for the measurement of gas diffusion and non-aqueous phase liquid (NAPL) saturation in soil.

    Science.gov (United States)

    Van De Steene, Joke; Höhener, Patrick

    2009-01-01

    During soil bioremediation, the diffusion of oxygen into the soil is an important prerequisite for aerobic biodegradation, and the decrease of petroleum products is the ultimate goal. Both processes need to be monitored. The aim of this work was to develop a gas tracer test that yields information on both, gas diffusion and residual saturation with non-aqueous phase liquids (NAPLs) in unsaturated soil heaps. One conservative tracer (methane) and 4 partitioning gas tracers (diethylether, methyl tert-butyl ether, chloroform and n-heptane) were injected as vapors into laboratory columns filled with unsaturated sand with increasing NAPL saturation. Breakthrough curves of gaseous compounds were measured at two points and compared to analytical solutions of an analytical diffusive-reactive transport equation. By fitting of methane data, robust results for effective diffusivity (tortuosity) were obtained. NAPL saturation was most accurately measured by the moderately water soluble tracers (ethers and chloroform). The hydrophobic tracer n-heptane did not partition into water-immersed NAPL. An easy and accurate way to assess air-NAPL partitioning constants from gas chromatography retention times is furthermore reported. It is concluded that gas tracer tests have the potential for measuring two important properties in soil bioremediation systems easily and quickly.

  15. [XPS Greenlight photoselective vaporization for benign prostatic hyperplasia: analysis of the learning curve and contribution of transrectal ultrasound monitoring].

    Science.gov (United States)

    Misrai, V; Faron, M; Elman, B; Bordier, B; Portalez, D; Guillotreau, J

    2013-09-01

    The aim of this study was to analyze the XPS laser learning curve of one single surgeon with no previous experience of PVP and the impact of the use of reel time transrectal ultrasound (TRUS) monitoring. Retrospective analysis of the first 100 patients: group 1 (1st-49th patient without TRUS) and group 2 (50th-100th with TRUS). The learning curve was analyzed through technical variables: vaporization time/intervention time (VT/IT) (%), energy delivered (J)/prostate volume (J/mL) and delivered energy (J/s or Watt), peroperative conversion into monopolar transurethral resection, postoperative complication, duration of catheterization and hospitalization and evolution of International Prostate Symptom Score (IPSS), PSA level, prostate residual volume and Qmax. Relationships between variables were evaluated by analysing the covariance (R 2 software. 14.2). A significant increase in VT/IT (P=0.0001) and the energy delivered per mL prostate (P=0.043) was reported in group 1. The average energy delivered per second was significantly higher in group 2 (P=0.0016). No difference was observed in terms of intra- or postoperative complication and catheterization time. The duration of hospitalization was significantly shorter in group 2 (P=0.03). The use of TRUS was associated with a gain of energy delivered by prostate volume at the end of learning curve (P=0.018). Prostate residual volume was significantly lower in the group 2 (P=0.0004). In our experience, 50 procedures are required to achieve the learning curve of PVP. The use of reel time TRUS would increase the energy delivered by prostate volume. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  16. On-line Monitoring System for Vapor Recovery in Oil Filling Station%加油站油气回收在线监测系统

    Institute of Scientific and Technical Information of China (English)

    孟振振; 吴锋棒; 张卫华

    2012-01-01

    In order to meet GB20952-2007 requirements and ensure vapor recovery in oil filling station, an on-line monitoring system for vapor recovery was developed. The test results from an oil filling station prove the system advantages of space saving, low cost and easy installation.%开发了加油站油气回收在线监测系统,实现了对加油站油气回收系统的在线监测,满足GB20952-2007的要求.该系统经过在模拟加油站的实验测试,已安装在中国石化北京某加油站试运行,运行效果良好,并具有占用空间小、成本低和施工安装方便的优点.

  17. Radon as geological tracer

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, T.; Anjos, R.M. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Fisica; Valladares, D.L.; Rizzotto, M.; Velasco, H.; Ayub, J. Juri [Universidad Nacional de San Luis (Argentina). Inst. de Matematica Aplicada San Luis (IMASL); Silva, A.A.R. da; Yoshimura, E.M. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica

    2012-07-01

    Full text: This work presents measurements of {sup 222}Rn levels performed in La Carolina gold mine and Los Condores tungsten mine at the province of San Luis, Argentina, today used for tourist visitation, and can evaluate the potential use of such radioactive noble gas as tracer or marker for geological processes in underground environments. By concentrations of {sup 40}K, {sup 232}Th and {sup 23}'8U were also measured in the walls of tunnels were determined the rocks mineral composition, what indicated that the mines have the same composition. In this sense, we used nuclear trace plastic detectors CR-39, gamma spectrometry of rock samples and Geiger-Muller (GM) monitors The patterns of radon gas transportation processes revealed that La Carolina could be interpreted through a model based on a radioactive gas confined into a single entrance tube, with constant cross section and air velocity. Los Condores, which has a second main entrance, could be interpreted through a model based on a radioactive gas confined into a two entrance tube, allowing a chimney effect for air circulation. The results showed the high potential of using {sup 222}Rn as a geological tracer. In what concerns the occupational hazard, in summer (time of more intense tourist activity in the mine) La Carolina presented a mean concentration of the radioactive noble gas that exceeds in four times the action level of 1,5 kBq m{sup -3} recommended by the International Commission of Radiological Protection (ICRP). The chimney effect shows the low mean concentration of radon in Los Condores. (author)

  18. On-line Monitoring Syste m for Oil Vapor Recovery in Filling Station%加油站油气回收在线监控系统

    Institute of Scientific and Technical Information of China (English)

    王振中; 金帼; 吴锋棒; 王洁

    2014-01-01

    为保证油气回收过程中的各项指标满足国家标准的要求,部分加油站应用电子式气液比调节设备和油气回收在线监测系统。在实际应用过程中,二者在功能原理上有较多的相似性,结合二者的功能特点,设计了兼具调节和监测功能的油气回收在线监控系统,能有效降低加油站的一次投资成本,提高气液比调节的长期稳定性。%In order to control VOC emission in the oil vapor recovery,some filling stations employ both gas liquid ratio regulating equipment and on-line monitoring system.Considering their similarity in working princi-ple and functional characteristics,an on-line monitoring system which boasting of regulation and monitoring functions for the oil vapor recovery was designed to effectively reduce the cost and improve gas liquid ratio for long time.

  19. Modeling and Real-Time Process Monitoring of Organometallic Chemical Vapor Deposition of III-V Phosphides and Nitrides at Low and High Pressure

    Science.gov (United States)

    Bachmann, K. J.; Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Sukidi, N.; McCall, S.

    1999-01-01

    The purpose of this paper is to review modeling and real-time monitoring by robust methods of reflectance spectroscopy of organometallic chemical vapor deposition (OMCVD) processes in extreme regimes of pressure. The merits of p-polarized reflectance spectroscopy under the conditions of chemical beam epitaxy (CBE) and of internal transmission spectroscopy and principal angle spectroscopy at high pressure are assessed. In order to extend OMCVD to materials that exhibit large thermal decomposition pressure at their optimum growth temperature we have designed and built a differentially-pressure-controlled (DCP) OMCVD reactor for use at pressures greater than or equal to 6 atm. We also describe a compact hard-shell (CHS) reactor for extending the pressure range to 100 atm. At such very high pressure the decomposition of source vapors occurs in the vapor phase, and is coupled to flow dynamics and transport. Rate constants for homogeneous gas phase reactions can be predicted based on a combination of first principles and semi-empirical calculations. The pressure dependence of unimolecular rate constants is described by RRKM theory, but requires variational and anharmonicity corrections not included in presently available calculations with the exception of ammonia decomposition. Commercial codes that include chemical reactions and transport exist, but do not adequately cover at present the kinetics of heteroepitaxial crystal growth.

  20. Packet Tracer network simulator

    CERN Document Server

    Jesin, A

    2014-01-01

    A practical, fast-paced guide that gives you all the information you need to successfully create networks and simulate them using Packet Tracer.Packet Tracer Network Simulator is aimed at students, instructors, and network administrators who wish to use this simulator to learn how to perform networking instead of investing in expensive, specialized hardware. This book assumes that you have a good amount of Cisco networking knowledge, and it will focus more on Packet Tracer rather than networking.

  1. A validation of the application of D(2)O stable isotope tracer techniques for monitoring day-to-day changes in muscle protein subfraction synthesis in humans.

    Science.gov (United States)

    Wilkinson, Daniel J; Franchi, Martino V; Brook, Matthew S; Narici, Marco V; Williams, John P; Mitchell, William K; Szewczyk, Nathaniel J; Greenhaff, Paul L; Atherton, Philip J; Smith, Kenneth

    2014-03-01

    Quantification of muscle protein synthesis (MPS) remains a cornerstone for understanding the control of muscle mass. Traditional [(13)C]amino acid tracer methodologies necessitate sustained bed rest and intravenous cannulation(s), restricting studies to ~12 h, and thus cannot holistically inform on diurnal MPS. This limits insight into the regulation of habitual muscle metabolism in health, aging, and disease while querying the utility of tracer techniques to predict the long-term efficacy of anabolic/anticatabolic interventions. We tested the efficacy of the D2O tracer for quantifying MPS over a period not feasible with (13)C tracers and too short to quantify changes in mass. Eight men (22 ± 3.5 yr) undertook one-legged resistance exercise over an 8-day period (4 × 8-10 repetitions, 80% 1RM every 2nd day, to yield "nonexercised" vs. "exercise" leg comparisons), with vastus lateralis biopsies taken bilaterally at 0, 2, 4, and 8 days. After day 0 biopsies, participants consumed a D2O bolus (150 ml, 70 atom%); saliva was collected daily. Fractional synthetic rates (FSRs) of myofibrillar (MyoPS), sarcoplasmic (SPS), and collagen (CPS) protein fractions were measured by GC-pyrolysis-IRMS and TC/EA-IRMS. Body water initially enriched at 0.16-0.24 APE decayed at ~0.009%/day. In the nonexercised leg, MyoPS was 1.45 ± 0.10, 1.47 ± 0.06, and 1.35 ± 0.07%/day at 0-2, 0-4, and 0-8 days, respectively (~0.05-0.06%/h). MyoPS was greater in the exercised leg (0-2 days: 1.97 ± 0.13%/day; 0-4 days: 1.96 ± 0.15%/day, P < 0.01; 0-8 days: 1.79 ± 0.12%/day, P < 0.05). CPS was slower than MyoPS but followed a similar pattern, with the exercised leg tending to yield greater FSRs (0-2 days: 1.14 ± 0.13 vs. 1.45 ± 0.15%/day; 0-4 days: 1.13 ± 0.07%/day vs. 1.47 ± 0.18%/day; 0-8 days: 1.03 ± 0.09%/day vs. 1.40 ± 0.11%/day). SPS remained unchanged. Therefore, D2O has unrivaled utility to quantify day-to-day MPS in humans and inform on short-term changes in anabolism and

  2. Modification and calibration of a passive air sampler for monitoring vapor and particulate phase brominated flame retardants in indoor air: application to car interiors.

    Science.gov (United States)

    Abdallah, Mohamed Abou-Elwafa; Harrad, Stuart

    2010-04-15

    A passive air sampler was modified to monitor both vapor and particulate phase brominated flame retardants (BFRs) in indoor air using polyurethane foam disks and glass fiber filters (GFF). Significant correlation (p GFF was investigated using environmental scanning electron microscopy which revealed gravitational deposition of particles as the main mechanism involved. The developed sampler was applied to monitor BFR concentrations in 21 cars. Average concentrations of SigmaHBCDs, TBBP-A, and Sigmatetra-deca BDEs were 400, 3, and 2200 pg m(-3) in cabins and 400, 1, and 1600 pg m(-3) in trunks. No significant differences (p < 0.05) were observed between levels of SigmaHBCDs and Sigmatrito hexa- BDEs in cabins and trunks. However, TBBP-A, BDE-209, and SigmaPBDEs concentrations were significantly higher in vehicle cabins.

  3. Microfabricated gas chromatograph for on-site determinations of TCE in indoor air arising from vapor intrusion. 2. Spatial/temporal monitoring.

    Science.gov (United States)

    Kim, Sun Kyu; Burris, David R; Bryant-Genevier, Jonathan; Gorder, Kyle A; Dettenmaier, Erik M; Zellers, Edward T

    2012-06-05

    We demonstrate the use of two prototype Si-microfabricated gas chromatographs (μGC) for continuous, short-term measurements of indoor trichloroethylene (TCE) vapor concentrations related to the investigation of TCE vapor intrusion (VI) in two houses. In the first house, with documented TCE VI, temporal variations in TCE air concentrations were monitored continuously for up to 48 h near the primary VI entry location under different levels of induced differential pressure (relative to the subslab). Concentrations ranged from 0.23 to 27 ppb by volume (1.2-150 μg/m(3)), and concentration trends agreed closely with those determined from concurrent reference samples. The sensitivity and temporal resolution of the measurements were sufficiently high to detect transient fluctuations in concentration resulting from short-term changes in variables affecting the extent of VI. Spatial monitoring showed a decreasing TCE concentration gradient with increasing distance from the primary VI entry location. In the second house, with no TCE VI, spatial profiles derived from the μGC prototype data revealed an intentionally hidden source of TCE within a closet, demonstrating the capability for locating non-VI sources. Concentrations measured in this house ranged from 0.51 to 56 ppb (2.7-300 μg/m(3)), in good agreement with reference method values. This first field demonstration of μGC technology for automated, near-real-time, selective VOC monitoring at low- or subppb levels augurs well for its use in short- and long-term on-site analysis of indoor air in support of VI assessments.

  4. Atmospheric and soil-gas monitoring for surface leakage at the San Juan Basin CO{sub 2} pilot test site at Pump Canyon New Mexico, using perfluorocarbon tracers, CO{sub 2} soil-gas flux and soil-gas hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Wells, Arthur W; Diehl, J Rodney; Strazisar, Brian R; Wilson, Thomas; H Stanko, Dennis C

    2012-05-01

    Near-surface monitoring and subsurface characterization activities were undertaken in collaboration with the Southwest Regional Carbon Sequestration Partnership on their San Juan Basin coal-bed methane pilot test site near Navajo City, New Mexico. Nearly 18,407 short tons (1.670 × 107 kg) of CO{sub 2} were injected into 3 seams of the Fruitland coal between July 2008 and April 2009. Between September 18 and October 30, 2008, two additions of approximately 20 L each of perfluorocarbon (PFC) tracers were mixed with the CO{sub 2} at the injection wellhead. PFC tracers in soil-gas and in the atmosphere were monitored over a period of 2 years using a rectangular array of permanent installations. Additional monitors were placed near existing well bores and at other locations of potential leakage identified during the pre-injection site survey. Monitoring was conducted using sorbent containing tubes to collect any released PFC tracer from soil-gas or the atmosphere. Near-surface monitoring activities also included CO{sub 2} surface flux and carbon isotopes, soil-gas hydrocarbon levels, and electrical conductivity in the soil. The value of the PFC tracers was demonstrated when a significant leakage event was detected near an offset production well. Subsurface characterization activities, including 3D seismic interpretation and attribute analysis, were conducted to evaluate reservoir integrity and the potential that leakage of injected CO{sub 2} might occur. Leakage from the injection reservoir was not detected. PFC tracers made breakthroughs at 2 of 3 offset wells which were not otherwise directly observable in produced gases containing 20–30% CO{sub 2}. These results have aided reservoir geophysical and simulation investigations to track the underground movement of CO{sub 2}. 3D seismic analysis provided a possible interpretation for the order of appearance of tracers at production wells.

  5. Identification of Alternative Vapor Intrusion Pathways Using Controlled Pressure Testing, Soil Gas Monitoring, and Screening Model Calculations.

    Science.gov (United States)

    Guo, Yuanming; Holton, Chase; Luo, Hong; Dahlen, Paul; Gorder, Kyle; Dettenmaier, Erik; Johnson, Paul C

    2015-11-17

    Vapor intrusion (VI) pathway assessment and data interpretation have been guided by an historical conceptual model in which vapors originating from contaminated soil or groundwater diffuse upward through soil and are swept into a building by soil gas flow induced by building underpressurization. Recent studies reveal that alternative VI pathways involving neighborhood sewers, land drains, and other major underground piping can also be significant VI contributors, even to buildings beyond the delineated footprint of soil and groundwater contamination. This work illustrates how controlled-pressure-method testing (CPM), soil gas sampling, and screening-level emissions calculations can be used to identify significant alternative VI pathways that might go undetected by conventional sampling under natural conditions at some sites. The combined utility of these tools is shown through data collected at a long-term study house, where a significant alternative VI pathway was discovered and altered so that it could be manipulated to be on or off. Data collected during periods of natural and CPM conditions show that the alternative pathway was significant, but its presence was not identifiable under natural conditions; it was identified under CPM conditions when measured emission rates were 2 orders of magnitude greater than screening-model estimates and subfoundation vertical soil gas profiles changed and were no longer consistent with the conventional VI conceptual model.

  6. Tracer attenuation in groundwater

    Science.gov (United States)

    Cvetkovic, Vladimir

    2011-12-01

    The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e., irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

  7. PROOF OF CONCEPT TEST OF A UNIQUE GASEOUS PERFLUROCARBON TRACER SYSTEM FOR VERIFICATION AND LONG TERM MONITORING OF CAPS AND COVER SYSTEMS CONDUCTED AT THE SAVANNAH RIVER SITE BENTONITE MAT TEST FACILITY.

    Energy Technology Data Exchange (ETDEWEB)

    HEISER,J.; SULLIVAN,T.; SERRATO,M.

    2002-02-24

    Engineered covers have been placed on top of buried/subsurface wastes to minimize water infiltration and therefore, release of hazardous contaminants. In order for the cover to protect the environment it must remain free of holes and breaches throughout its service life. Covers are subject to subsidence, erosion, animal intrusion, plant root infiltration, etc., all of which will affect the overall performance of the cover. The U.S. Department of Energy Environmental Management (DOE-EM) Program 2006 Accelerated Cleanup Plan is pushing for rapid closure of many of the DOE facilities. This will require a great number of new cover systems. Some of these new covers are expected to maintain their performance for periods of up to 1000 years. Long-term stewardship will require monitoring/verification of cover performance over the course of the designed lifetime. In addition, many existing covers are approaching the end of their design life and will need validation of current performance (if continued use is desired) or replacement (if degraded). The need for a reliable method of verification and long-term monitoring is readily apparent. Currently, failure is detected through monitoring wells downstream of the waste site. This is too late as the contaminants have already left the disposal area. The proposed approach is the use of gaseous Perfluorocarbon tracers (PFT) to verify and monitor cover performance. It is believed that PFTs will provide a technology that can verify a cover meets all performance objectives upon installation, be capable of predicting changes in cover performance and failure (defined as contaminants leaving the site) before it happens, and be cost-effective in supporting stewardship needs. The PFTs are injected beneath the cover and air samples taken above (either air samples or soil gas samples) at the top of the cover. The location, concentrations, and time of arrival of the tracer(s) provide a direct measure of cover performance. PFT technology can

  8. Tracer Dispersion in a Multi-compartment Structure

    CERN Document Server

    Skvortsov, A; Gamble, G; Roberts, M; Ilaya, O; Pitaliadda, D

    2012-01-01

    An experimental study of the tracer dispersion in a complex structure is presented. A point source of tracer (dyed salt) was placed inside a multi-compartment structure embedded in water tank. This experimental setting corresponds to a hazardous tracer release inside the engineering structure (building, ship, aircarft etc). A system of conductivity sensors was deployed to monitor the propagation of a tracer plume in the structure, including tracer trapping inside some compartments and its release to the outside environment through the external openings. The experimental data is processed by employing the ideas of scaling and self-similarity of underlying transport processes. The established and validated scaling laws provide a rigorous way to up-scale the results of laboratory modeling to real operational scenarios and can be used as an important step in the development of risk-assessment models for the first responders to hazardous releases. Keywords: hazardous plume, tracer dispersion, diffusion and advecti...

  9. (52)Fe translocation in barley as monitored by a positron-emitting tracer imaging system (PETIS): evidence for the direct translocation of Fe from roots to young leaves via phloem.

    Science.gov (United States)

    Tsukamoto, Takashi; Nakanishi, Hiromi; Uchida, Hiroshi; Watanabe, Satoshi; Matsuhashi, Shinpei; Mori, Satoshi; Nishizawa, Naoko K

    2009-01-01

    The real-time translocation of iron (Fe) in barley (Hordeum vulgare L. cv. Ehimehadaka no. 1) was visualized using the positron-emitting tracer (52)Fe and a positron-emitting tracer imaging system (PETIS). PETIS allowed us to monitor Fe translocation in barley non-destructively under various conditions. In all cases, (52)Fe first accumulated at the basal part of the shoot, suggesting that this region may play an important role in Fe distribution in graminaceous plants. Fe-deficient barley showed greater translocation of (52)Fe from roots to shoots than did Fe-sufficient barley, demonstrating that Fe deficiency causes enhanced (52)Fe uptake and translocation to shoots. In the dark, translocation of (52)Fe to the youngest leaf was equivalent to or higher than that under the light condition, while the translocation of (52)Fe to the older leaves was decreased, in both Fe-deficient and Fe-sufficient barley. This suggests the possibility that the mechanism and/or pathway of Fe translocation to the youngest leaf may be different from that to the older leaves. When phloem transport in the leaf was blocked by steam treatment, (52)Fe translocation from the roots to older leaves was not affected, while (52)Fe translocation to the youngest leaf was reduced, indicating that Fe is translocated to the youngest leaf via phloem in addition to xylem. We propose a novel model in which root-absorbed Fe is translocated from the basal part of the shoots and/or roots to the youngest leaf via phloem in graminaceous plants.

  10. Formaldehyde vapor produced from hexamethylenetetramine and pesticide: Simultaneous monitoring of formaldehyde and ozone in chamber experiments by flow-based hybrid micro-gas analyzer.

    Science.gov (United States)

    Yanaga, Akira; Hozumi, Naruto; Ohira, Shin-Ichi; Hasegawa, Asako; Toda, Kei

    2016-02-01

    Simultaneous analysis of HCHO and O3 was performed by the developed flow analysis system to prove that HCHO vapor is produced from solid pesticide in the presence of O3. HCHO is produced in many ways, including as primary emissions from fuel combustion and in secondary production from anthropogenic and biogenic volatile organic compounds by photochemical reactions. In this work, HCHO production from pesticides was investigated for the first time. Commonly pesticide contains surfactant such as hexamethylenetetramine (HMT), which is a heterocyclic compound formed from six molecules of HCHO and four molecules of NH3. HMT can react with gaseous oxidants such as ozone (O3) to produce HCHO. In the present study, a flow analysis system was developed for simultaneous analysis of HCHO and O3, and this system was used to determine if solid pesticides produced HCHO vapor in the presence of O3. HMT or the pesticide jimandaisen, which contains mancozeb as the active ingradient and HMT as a stabilizer was placed at the bottom of a 20-L stainless steel chamber. Air in the chamber was monitored using the developed flow system. Analyte gases were collected into an absorbing solution by a honeycomb-patterned microchannel scrubber that was previously developed for a micro gas analysis system (μGAS). Subsequently, indigotrisulfonate, a blue dye, was added to the absorbing solution to detect O3, which discolored the solution. HCHO was detected after mixing with the Hantzsch reaction reagent. Both gases could be detected at concentrations ranging from parts per billion by volume (ppbv) to 1000 ppbv with good linearity. Both HMT and jimandaisen emitted large amount of HCHO in the presence of O3.

  11. Measurements of Humidity in the Atmosphere: Validation Experiments (MOHAVE I and MOHAVE II). Results Overview and Implication for the Long-Term Lidar Monitoring of Water Vapor in the UT/LS

    Science.gov (United States)

    Leblanc, Thierry; McDermid, I. S.; Vomel, H.; Whiteman, D.; Twigg, Larry; McGee, T. G.

    2008-01-01

    1. MOHAVE+MOHAVE II = very successful. 2. MOHAVE -> Fluorescence was found to be inherent to all three participating lidars. 3. MOHAVE II -> Fluorescence was removed and agreement with CFH was extremely good up to 16-18 km altitude. 4. MOHAVE II -> Calibration tests revealed unsuspected shortfalls of widely used techniques, with important implications for their applicability to longterm measurements. 5. A factor of 5 in future lidar signal-to-noise ratio is reasonably achievable. When this level is achieved water vapor Raman lidar will become a key instrument for the long-term monitoring of water vapor in the UT/LS

  12. Vapor Bubbles

    Science.gov (United States)

    Prosperetti, Andrea

    2017-01-01

    This article reviews the fundamental physics of vapor bubbles in liquids. Work on bubble growth and condensation for stationary and translating bubbles is summarized and the differences with bubbles containing a permanent gas stressed. In particular, it is shown that the natural frequency of a vapor bubble is proportional not to the inverse radius, as for a gas bubble, but to the inverse radius raised to the power 2/3. Permanent gas dissolved in the liquid diffuses into the bubble with strong effects on its dynamics. The effects of the diffusion of heat and mass on the propagation of pressure waves in a vaporous bubbly liquid are discussed. Other topics briefly touched on include thermocapillary flow, plasmonic nanobubbles, and vapor bubbles in an immiscible liquid.

  13. A UV-to-MIR monitoring of DR Tau: exploring how water vapor in the planet formation region of the disk is affected by stellar accretion variability

    CERN Document Server

    Banzatti, Andrea; Manara, Carlo F; Pontoppidan, Klaus M; Testi, Leonardo

    2013-01-01

    Young stars are known to show variability due to non-steady mass accretion rate from their circumstellar disks. Accretion flares can produce strong energetic irradiation and heating that may affect the disk in the planet formation region, close to the central star. During an extreme accretion outburst in the young star EX Lupi, the prototype of EXor variables, remarkable changes in molecular gas emission from $\\sim1$ AU in the disk have recently been observed (Banzatti et al. 2012). Here, we focus on water vapor and explore how it is affected by variable accretion luminosity in T Tauri stars. We monitored a young highly variable solar-mass star, DR Tau, using simultaneously two high/medium-resolution ESO-VLT spectrographs: VISIR at 12.4 $\\mu$m to observe water lines from the disk, and X-shooter covering from 0.3 to 2.5 $\\mu$m to constrain the stellar accretion. Three epochs spanning timescales from several days to several weeks were obtained. Accretion luminosity was estimated to change within a factor $\\sim2...

  14. Southeast Geyers Cooperative Tracer Evaluation and Testing Program for the Purpose of Estimating The Efficiency of Injection

    Energy Technology Data Exchange (ETDEWEB)

    J.L. (Bill) Smith

    2001-02-12

    The Southeast Geysers Cooperative Tracer Evaluation Program has been a joint project located in the SE part of the Geysers geothermal field, in Lake and Sonoma Counties, California. A new generation of environmentally benign vapor-phase tracers has been used to estimate the varying degrees to which injectate is being recovered following the significant increase of injected volumes within the Southeast Geysers.

  15. Toxicity of fluorescent tracers and their degradation byproducts

    Directory of Open Access Journals (Sweden)

    Philippe Gombert

    2017-01-01

    Full Text Available Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and air action. The paper presents firstly the laboratory degradation of a first batch of fluorescent tracers in contact with chlorine, in order to simulate their passage through a water treatment system for human consumption. A second batch of the same tracers is subjected to agents of natural degradation: ultraviolet illumination, sunlight and air sparging. Most tracers is degraded, and toxicity and ecotoxicity tests (on rats, daphniae and algae are performed on degradation byproducts. These tests do not show any acute toxicity but a low to moderate ecotoxicity. In conclusion, the most used fluorescent tracers of the Normandy karstic chalk and their artificial and natural degradation byproducts do not exhibit significant toxicity to humans and the aquatic environment, at the concentrations generally noted at the restitution points.

  16. ER Operations Installation of Three FLUTe Soil-Vapor Monitoring Wells (MWL-SV03 MWL-SV04 and MWL-SV05) at the Mixed Waste Landfill.

    Energy Technology Data Exchange (ETDEWEB)

    Copland, John Robin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    This installation report describes the May through July 2014 drilling activities performed for the installation of three multi-port soil-vapor monitoring wells (MWL-SV03, MWL-SV04, and MWL-SV05) at the Mixed Waste Landfill (MWL), which is located at Sandia National Laboratories, New Mexico (SNL/NM). SNL/NM is managed and operated by Sandia Corporation (Sandia), a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy (DOE)/National Nuclear Security Administration. The MWL is designated as Solid Waste Management Unit (SWMU) 76 and is located in Technical Area (TA) III (Figure 1-1). The locations of the three soil-vapor monitoring wells (MWL-SV03, MWL-SV04, and MWL-SV05) are shown in Figure 1-2

  17. Journal: Efficient Hydrologic Tracer-Test Design for Tracer ...

    Science.gov (United States)

    Hydrological tracer testing is the most reliable diagnostic technique available for the determination of basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed to facilitate the design of tracer tests by root determination of the one-dimensional advection-dispersion equation (ADE) using a preset average tracer concentration which provides a theoretical basis for an estimate of necessary tracer mass. The method uses basic measured field parameters (e.g., discharge, distance, cross-sectional area) that are combined in functional relatipnships that descrive solute-transport processes related to flow velocity and time of travel. These initial estimates for time of travel and velocity are then applied to a hypothetical continuous stirred tank reactor (CSTR) as an analog for the hydrological-flow system to develop initial estimates for tracer concentration, tracer mass, and axial dispersion. Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to be necessary for descri

  18. Tracer tomography (in) rocks!

    Science.gov (United States)

    Somogyvári, Márk; Jalali, Mohammadreza; Jimenez Parras, Santos; Bayer, Peter

    2016-04-01

    Physical behavior of fractured aquifers is rigorously controlled by the presence of interconnected conductive fractures, as they represent the main pathways for flow and transport. Ideally, they are simulated as a discrete fracture network (DFN) in a model to capture the role of fracture system geometry, i.e. fracture length, height, and width (aperture/transmissivity). Such network may be constrained by prior geological information or direct data resources such as field mapping, borehole logging and geophysics. With the many geometric features, however, calibration of a DFN to measured data is challenging. This is especially the case when spatial properties of a fracture network need to be calibrated to flow and transport data. One way to increase the insight in a fractured rock is by combining the information from multiple field tests. In this study, a tomographic configuration that combines multiple tracer tests is suggested. These tests are conducted from a borehole with different injection levels that act as sources. In a downgradient borehole, the tracer is recorded at different levels or receivers, in order to maximize insight in the spatial heterogeneity of the rock. As tracer here we chose heat, and temperature breakthrough curves are recorded. The recorded tracer data is inverted using a novel stochastic trans-dimensional Markov Chain Monte Carlo procedure. An initial DFN solution is generated and sequentially modified given available geological information, such as expected fracture density, orientation, length distribution, spacing and persistency. During this sequential modification, the DFN evolves in a trans-dimensional inversion space through adding and/or deleting fracture segments. This stochastic inversion algorithm requires a large number of thousands of model runs to converge, and thus using a fast and robust forward model is essential to keep the calculation efficient. To reach this goal, an upwind coupled finite difference method is employed

  19. Development of radioisotope tracer technology

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Joon Ha; Lee, Myun Joo; Jung, Sung Hee; Park, Soon Chul; Lim, Dong Soon; Kim, Jae Ho; Lee, Jae Choon; Lee, Doo Sung; Cho, Yong Suk; Shin, Sung Kuan

    2000-04-01

    The purpose of this study is to develop the radioisotope tracer technology, which can be used in solving industrial and environmental problems and to build a strong tracer group to support the local industries. In relation to the tracer technology in 1999, experiments to estimate the efficiencies of a sludge digester of a waste water treatment plant and a submerged biological reactor of a dye industry were conducted. As a result, the tracer technology for optimization of facilities related to wastewater treatment has been developed and is believed to contribute to improve their operation efficiency. The quantification of the experimental result was attempted to improve the confidence of tracer technology by ECRIN program which basically uses the MCNP simulation principle. Using thin layer activation technique, wear of tappet shim was estimated. Thin layer surface of a tappet shim was irradiated by proton beam and the correlation between the measured activity loss and the amount of wear was established. The equipment was developed to adjust the energy of proton which collides with the surface of tappet. The tracer project team has participated into the tracer test for estimating the efficiency of RFCC system in SK cooperation. From the experiment the tracer team has obtained the primary elements to be considered for judging the efficiency of RFCC unit. By developing the tracer techniques to test huge industrial units like RFCC, the tracer team will be able to support the local industries that require technical services to solve any urgent trouble. (author)

  20. Chemical Tracer Methods: Chapter 7

    Science.gov (United States)

    Healy, Richard W.

    2017-01-01

    Tracers have a wide variety of uses in hydrologic studies: providing quantitative or qualitative estimates of recharge, identifying sources of recharge, providing information on velocities and travel times of water movement, assessing the importance of preferential flow paths, providing information on hydrodynamic dispersion, and providing data for calibration of water flow and solute-transport models (Walker, 1998; Cook and Herczeg, 2000; Scanlon et al., 2002b). Tracers generally are ions, isotopes, or gases that move with water and that can be detected in the atmosphere, in surface waters, and in the subsurface. Heat also is transported by water; therefore, temperatures can be used to trace water movement. This chapter focuses on the use of chemical and isotopic tracers in the subsurface to estimate recharge. Tracer use in surface-water studies to determine groundwater discharge to streams is addressed in Chapter 4; the use of temperature as a tracer is described in Chapter 8.Following the nomenclature of Scanlon et al. (2002b), tracers are grouped into three categories: natural environmental tracers, historical tracers, and applied tracers. Natural environmental tracers are those that are transported to or created within the atmosphere under natural processes; these tracers are carried to the Earth’s surface as wet or dry atmospheric deposition. The most commonly used natural environmental tracer is chloride (Cl) (Allison and Hughes, 1978). Ocean water, through the process of evaporation, is the primary source of atmospheric Cl. Other tracers in this category include chlorine-36 (36Cl) and tritium (3H); these two isotopes are produced naturally in the Earth’s atmosphere; however, there are additional anthropogenic sources of them.

  1. Monitoring percolation of a conductive tracer, as a proxy for nitrate transport, through glacial till and fractured sandstone in the vadose zone underlying a potato field, using 3D cross-hole electrical resistivity imaging

    Science.gov (United States)

    Wang, S.; Butler, K. E.; Serban, D.; Petersen, B.; Grimmett, M.

    2016-12-01

    Nitrate is a necessary nutrient for crops, but high surface water and groundwater concentrations can negatively affect aquatic ecosystem and human health. At AAFC-AAC Harrington Research Farm (PEI, Canada), 3D cross-hole electrical resistivity imaging (ERI) is being used to investigate the percolation of a conductive tracer (KCl) through a 17 m thick vadose zone as a proxy for the transport of nitrate under natural recharge conditions. The objectives are to investigate the effect of heterogeneity on transport pathways and infer how long it would take for changes in farming practices at the surface to affect nitrate loading to the underlying aquifer. The resistivity array consists of 96 permanently installed electrodes - 24 at 0.68 m spacing in each of three 16 m deep boreholes arranged in a triangle with 9 m sides, and 24 at 1 m spacing buried in shallow trenches connecting the boreholes. A background survey revealed five sub-horizontal layers of alternating resistivity in general agreement with the geology of 6 m soil and glacial till overburden overlying interbedded sandstone and shaley sandstone layers. On March 27th, 2015, 1.1 m of snow was removed from a 15.2 m2 area positioned symmetrically inside the triangular array and 100 kg of granular KCl was distributed on the ground surface. The removed snow was immediately replaced to await the spring thaw. Post-tracer surveys indicate tracer had percolated to depths of 1 m, 1.2 m, 3.0 m and 3.5 m by the 4th, 26th, 30th, and 46th days after tracer application. Its movement slowed significantly by early May, 2015, with the end of snow melt. Tracer spread laterally very slowly through the summer and early fall, 2015, but has remained within the triangular array. The shallow conductivity anomaly produced by the tracer diminished significantly over the winter and spring of 2016 but showed little evidence of bulk matrix flow below 3.5 m depth. It is speculated that fractures in the glacial till, too thin to be resolved by

  2. Exotic tracers for atmospheric studies

    Energy Technology Data Exchange (ETDEWEB)

    Lovelock, J.E. (Brazzos Ltd., Launceston (UK)); Ferber, G.J. (National Oceanic and Atmospheric Administration, Silver Spring, MD (USA). Air Resources Lab.)

    1982-01-01

    Tracer materials can be injected into the atmosphere to study transport and dispersion processes and to validate air pollution model calculations. Tracers should be inert, non-toxic and harmless to the environment. Tracers for long-range experiments, where dilution is very great, must be measurable at extremely low concentrations, well below the parts per trillion level. Compounds suitable for long-range tracer work are rare and efforts should be made to reserve them for meteorological studies, barring them from commercial uses which would increase atmospheric background concentrations. The use of these exotic tracers, including certain perfluorocarbons and isotopically labelled methanes, should be coordinated within the meteorological community to minimize interferences and maximise research benefits.

  3. Exotic tracers for atmospheric studies

    Science.gov (United States)

    Lovelock, James E.; Ferber, Gilbert J.

    Tracer materials can be injected into the atmosphere to study transport and dispersion processes and to validate air pollution model calculations. Tracers should be inert, non-toxic and harmless to the environment. Tracers for long-range experiments, where dilution is very great, must be measurable at extremely low concentrations, well below the parts per trillion level. Compounds suitable for long-range tracer work are rare and efforts should be made to reserve them for meteorological studies, barring them from commercial uses which would increase atmospheric background concentrations. The use of these exotic tracers, including certain perfluorocarbons and isotopically labelled methanes, should be coordinated within the meteorological community to minimize interferences and maximize research benefits.

  4. Small molecules as tracers in atmospheric secondary organic aerosol

    Science.gov (United States)

    Yu, Ge

    Secondary organic aerosol (SOA), formed from in-air oxidation of volatile organic compounds, greatly affects human health and climate. Although substantial research has been devoted to SOA formation and evolution, the modeled and lab-generated SOA are still low in mass and degree of oxidation compared to ambient measurements. In order to compensate for these discrepancies, the aqueous processing pathway has been brought to attention. The atmospheric waters serve as aqueous reaction media for dissolved organics to undergo further oxidation, oligomerization, or other functionalization reactions, which decreases the vapor pressure while increasing the oxidation state of carbon atoms. Field evidence for aqueous processing requires the identification of tracer products such as organosulfates. We synthesized the standards for two organosulfates, glycolic acid sulfate and lactic acid sulfate, in order to measure their aerosol-state concentration from five distinct locations via filter samples. The water-extracted filter samples were analyzed by LC-MS. Lactic acid sulfate and glycolic acid sulfate were detected in urban locations in the United States, Mexico City, and Pakistan with varied concentrations, indicating their potential as tracers. We studied the aqueous processing reaction between glyoxal and nitrogen-containing species such as ammonium and amines exclusively by NMR spectrometry. The reaction products formic acid and several imidazoles along with the quantified kinetics were reported. The brown carbon generated from these reactions were quantified optically by UV-Vis spectroscopy. The organic-phase reaction between oxygen molecule and alkenes photosensitized by alpha-dicarbonyls were studied in the same manner. We observed the fast kinetics transferring alkenes to epoxides under simulated sunlight. Statistical estimations indicate a very effective conversion of aerosol-phase alkenes to epoxides, potentially forming organosulfates in a deliquescence event and

  5. Correction Technique for Raman Water Vapor Lidar Signal-Dependent Bias and Suitability for Water Wapor Trend Monitoring in the Upper Troposphere

    Science.gov (United States)

    Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.; Jordan, A.; Voemel, H.

    2012-01-01

    The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and Education) mobile laboratory in the MOHAVE-2009 campaign. In appendices we also report on the performance of the corrected Vaisala RS92 radiosonde measurements during the campaign, on a new radiosonde based calibration algorithm that reduces the influence of atmospheric variability on the derived calibration constant, and on other results of the ALVICE deployment. The MOHAVE-2009 campaign permitted the Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated, revealing that wet biases in upper tropospheric (UT) and lower stratospheric (LS) water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the bias. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Good agreement is found between corrected ALVICE lidar measurments and those of RS92, frost point hygrometer and total column water. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most robust. The correction shown here holds promise for permitting useful upper

  6. Proceedings of the atmospheric tracers and tracer application workshop

    Energy Technology Data Exchange (ETDEWEB)

    Barr, S.; Gedayloo, T. (comps.)

    1979-12-01

    In addition to presentations by participating members a general discussion was held in order to summarize and outline the goals and objectives of the workshop. A number of new low level background tracers such as heavy methanes, perfluorocarbons, multiply labeled isotopes such as /sup 13/C/sup 18/O/sub 2/, helium 3, in addition to sample collection techniques and analytical methods for various tracers were discussed. This report is a summary of discussions and papers presented at this workshop.

  7. Quantifying solute transport processes: are chemically "conservative" tracers electrically conservative?

    Science.gov (United States)

    Singha, Kamini; Li, Li; Day-Lewis, Frederick D.; Regberg, Aaron B.

    2012-01-01

    The concept of a nonreactive or conservative tracer, commonly invoked in investigations of solute transport, requires additional study in the context of electrical geophysical monitoring. Tracers that are commonly considered conservative may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system. As a result, the measured electrical conductivity may reflect not only solute transport but also reactive processes. We have evaluated the impacts of ion exchange reactions, rate-limited mass transfer, and surface conduction on quantifying tracer mass, mean arrival time, and temporal variance in laboratory-scale column experiments. Numerical examples showed that (1) ion exchange can lead to resistivity-estimated tracer mass, velocity, and dispersivity that may be inaccurate; (2) mass transfer leads to an overestimate in the mobile tracer mass and an underestimate in velocity when using electrical methods; and (3) surface conductance does not notably affect estimated moments when high-concentration tracers are used, although this phenomenon may be important at low concentrations or in sediments with high and/or spatially variable cation-exchange capacity. In all cases, colocated groundwater concentration measurements are of high importance for interpreting geophysical data with respect to the controlling transport processes of interest.

  8. Interpretation of Water Tracer Simulation in the H-1 Segment of the Gullfaks Field

    Energy Technology Data Exchange (ETDEWEB)

    Moid, Farrukh

    2000-07-01

    This thesis describes the water tracer simulation in the H-1 segment of the Gullfaks field. Three passive water tracer slugs were injected from the two producing wells during water flooding, pressure maintenance and reservoir monitoring program in the Gullfaks field. The same program is considered in this thesis. Computer Modelling Group's (CMG) simulator STARS is used for the general reservoir simulation and a separate module for tracer flow (ITRC-SIM) which is incorporated in the STARS and developed at Institute For Energy (IFE) is used for the tracer simulation. Water cut and tracer concentration data are used in history matching of the field. History matching is performed by changing the transmissibility and permeability of different layers; also the effect of changing saturations near the well bore on history matching is examined. It is noted that water cut is sensitive to transmissibility of the layers and the saturation around the well bore. Tracers are found to be moving in the most permeable layers. The corresponding history matching of water and tracer production shows a severe loss of first tracer injected because of imbibition process. Water phase velocity and areal communication between different wells are determined. Advance numerical features of tracer module ITRC-SIM such as flux limiting scheme and grid refinement scheme are evaluated and are found to be an important tool for reducing the numerical smearing. The effects of dispersion and diffusion on tracer response curve are also evaluated. Dispersion makes the tracer concentration curve smeared. Simulation results of water cut and tracer concentration show a good history match for this reservoir. The improved simulation model and the tracer module for this reservoir can be used for the prediction of future performance of the reservoir and interpretation of the tracer behaviour in the reservoir. (author)

  9. Construction and Application about the Monitoring System of Water Vapor Derived from Ground-based GPS in Chengdu%成都地基的GPS水汽监测系统建设与应用

    Institute of Scientific and Technical Information of China (English)

    王皓; 李国平

    2011-01-01

    Water vapor plays a very important role in weather and climate changes. Though water vapor is very little in the atmosphere, but its change, in the atmosphere, is very obvious. Water vapor is also an important kind of greenhouse gas in the atmosphere whose spatial distribution is extremely uneven and time variation is very fast. It is not only the main driving force of weather and climate changes, but also an important formation and evolution reason for disastrous weather, especially medium or small scale disastrous weather. In satellite geodesy, GPS positioning accuracy was primarily affected by water vapor.Therefore, people learn from the elimination of noise in the measurement process, gradually to develop out of a new discipline—GPS meteorology (GPS/MET). Along with the development of GPS meteorology, people start to utilize ground-based GPS technology in order to effectively compensate for the defects of traditional detection technologies spatially and temporally and obtain water vapor information with high-precision, high-capacity and high space-time resolution ratio through ground-based GPS water vapor monitoring network. How to measure water vapor content in the atmosphere, to monitor the distribution of water vapor and its trends, which have an important practical significance to meteorological department, especially in monitoring and forecasting disastrous weather on a medium or small scale. The main content of this paper is to launch the development of ground-based GPS water vapor monitoring system;the purpose is to make this system fill in the blank of the application of GPS inversion water vapor technology in Sichuan and even the southwest areas of China, and also enhance the capacities of meteorological department on forecasting and monitoring of medium or small scale disastrous weather, as well as promote the work of many related meteorological operations.%水汽尽管在大气中的含量很少,但是其在大气中的变化却十分剧烈.其空

  10. Driven tracers in narrow channels

    Science.gov (United States)

    Cividini, J.; Mukamel, D.; Posch, H. A.

    2017-01-01

    Steady-state properties of a driven tracer moving in a narrow two-dimensional (2D) channel of quiescent medium are studied. The tracer drives the system out of equilibrium, perturbs the density and pressure fields, and gives the bath particles a nonzero average velocity, creating a current in the channel. Three models in which the confining effect of the channel is probed are analyzed and compared in this study: the first is the simple symmetric exclusion process (SSEP), for which the stationary density profile and the pressure on the walls in the frame of the tracer are computed. We show that the tracer acts like a dipolar source in an average velocity field. The spatial structure of this 2D strip is then simplified to a one-dimensional (1D) SSEP, in which exchanges of position between the tracer and the bath particles are allowed. Using a combination of mean-field theory and exact solution in the limit where no exchange is allowed gives good predictions of the velocity of the tracer and the density field. Finally, we show that results obtained for the 1D SSEP with exchanges also apply to a gas of overdamped hard disks in a narrow channel. The correspondence between the parameters of the SSEP and of the gas of hard disks is systematic and follows from simple intuitive arguments. Our analytical results are checked numerically.

  11. Real-Time Optical Monitoring and Simulations of Gas Phase Kinetics in InN Vapor Phase Epitaxy at High Pressure

    Science.gov (United States)

    Dietz, Nikolaus; Woods, Vincent; McCall, Sonya D.; Bachmann, Klaus J.

    2003-01-01

    Understanding the kinetics of nucleation and coalescence of heteroepitaxial thin films is a crucial step in controlling a chemical vapor deposition process, since it defines the perfection of the heteroepitaxial film both in terms of extended defect formation and chemical integrity of the interface. The initial nucleation process also defines the film quality during the later stages of film growth. The growth of emerging new materials heterostructures such as InN or In-rich Ga(x)In(1-x)N require deposition methods operating at higher vapor densities due to the high thermal decomposition pressure in these materials. High nitrogen pressure has been demonstrated to suppress thermal decomposition of InN, but has not been applied yet in chemical vapor deposition or etching experiments. Because of the difficulty with maintaining stochiometry at elevated temperature, current knowledge regarding thermodynamic data for InN, e.g., its melting point, temperature-dependent heat capacity, heat and entropy of formation are known with far less accuracy than for InP, InAs and InSb. Also, no information exists regarding the partial pressures of nitrogen and phosphorus along the liquidus surfaces of mixed-anion alloys of InN, of which the InN(x)P(1-x) system is the most interesting option. A miscibility gap is expected for InN(x)P(1-x) pseudobinary solidus compositions, but its extent is not established at this point by experimental studies under near equilibrium conditions. The extension of chemical vapor deposition to elevated pressure is also necessary for retaining stoichiometric single phase surface composition for materials that are characterized by large thermal decomposition pressures at optimum processing temperatures.

  12. Petroleum Vapor Intrusion

    Science.gov (United States)

    One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

  13. Real-Time Monitoring of Atom Vapor Concentration With Laser Absorption Spectroscopy%激光吸收光谱法实时监测原子蒸气密度

    Institute of Scientific and Technical Information of China (English)

    范凤英; 高鹏; 江涛

    2012-01-01

    采用固体激光器泵浦环形染料激光器作为光源,通过激光吸收光谱法对钆原子蒸气密度进行实时监测.应用光纤远距离传输提高光路稳定性,采用多步吸收光程技术,并引入参考光消除激光功率不稳定因素影响.实验结果表明:采用该方法建立的原子蒸气密度实时监测系统标准误差约为4%,可为激光同位素分离过程提供可靠数据,从而提高分离效率.%The technology of laser absorption spectroscopy was used for real-time monitoring of gadolinium atom vapor concentration measurement and the solid state laser pumped ring dye laser was used as optical source. The optical fiber was taken to improve the stability of laser transmission. The multi-pass absorption technology combined with reference optical signal avoided the influence of laser power fluctuation. The experiment result shows that the system based on this detection method has a standard error of 4%. It is proved that the monitoring system provides reliable data for atom vapor laser isotope separation process and the separation efficiency can be improved.

  14. Tracer Diffusion in a Soft Glassy Material

    Science.gov (United States)

    Petit, Laure; Barentin, Catherine; Colombani, Jean; Ybert, Christophe; Barrat, Jean-Louis; Bocquet, Lydéric

    2008-07-01

    We have carried out Fluorescence Recovery After Photobleaching measurements of the diffusion of tracers of various sizes in a colloidal glass (a Laponite suspension). We have shown that the diffusion is only dependent on the ratio of the tracer size and the distance between Laponite disks. This suggests that the tracer diffusion hindrance in the glass stems from the hydrodynamical interactions between the tracer and the Laponite network, the physico-chemical Laponite-tracer interaction playing a negligible role.

  15. Ground-based water vapor Raman lidar measurements up to the upper troposphere and lower stratosphere – Part 2: Data analysis and calibration for long-term monitoring

    Directory of Open Access Journals (Sweden)

    T. Leblanc

    2011-08-01

    Full Text Available The well-recognized, key role of water vapor in the upper troposphere and lower stratosphere (UT/LS and the scarcity of high-quality, long-term measurements triggered the development by JPL of a powerful Raman lidar to try to meet these needs. This development started in 2005 and was endorsed by the Network for the Detection of Atmospheric Composition Change (NDACC and the validation program for the EOS-Aura satellite. In this paper we review all the stages of the instrument data acquisition, data analysis, profile retrieval and calibration procedures, as well as selected results from the recent validation campaign MOHAVE-2009 (Measurements of Humidity in the Atmosphere and Validation Experiments. The stages in the instrumental development and the conclusions from three validation campaigns (including MOHAVE-2009 are presented in details in a companion paper (McDermid et al., 2011. In its current configuration, the lidar demonstrated capability to measure water vapor profiles from ~1 km above the ground to the lower stratosphere with an estimated accuracy of 5 %. Since 2005, nearly 1000 profiles have been routinely measured with a precision of 10 % or better near 13 km. Since 2009, the profiles have typically reached 14 km for 1 h integration times and 1.5 km vertical resolution, and can reach 21 km for 6-h integration times using degraded vertical resolutions.

  16. Development of radioisotope tracer technology and nucleonic control system

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Joon Ha; Lee, Myun Joo; Jung, Sung Hee and others

    1999-04-01

    The purpose of this study is to develop the radioisotope tracer technology, which can be used in solving industrial and environmental problems and basic technology of nuclear control systems that are widely used for automation of industrial plants, and to build a strong tracer group to support the local industries. In relation to the tracer technology, the data acquisition system, the column scanning equipment and the detection pig for a leakage test have been developed. In order to use in analyzing data of tracer experiments, a computer program for the analysis of residence time distribution has been created as well. These results were utilized in developing the tracer technologies, such as the column scanning, the flow measurement using the dilution method, the simultaneous monitoring rotational movement of piston rings and the optimization of a waste water treatment facility, and the technologies were successfully demonstrated in the local industrial. The stripper of RFCC reactor has been examined to find an unwanted structure in it by imminent request from the industry. Related to the development of nucleonic control system, the state of art report on the technology has been written and an equipment for the analysis of asphalt content has been developed. (author)

  17. Distribution of Water Vapor in Molecular Clouds

    CERN Document Server

    Melnick, Gary J; Snell, Ronald L; Bergin, Edwin A; Hollenbach, David J; Kaufman, Michael J; Li, Di; Neufeld, David A

    2010-01-01

    We report the results of a large-area study of water vapor along the Orion Molecular Cloud ridge, the purpose of which was to determine the depth-dependent distribution of gas-phase water in dense molecular clouds. We find that the water vapor measured toward 77 spatial positions along the face-on Orion ridge, excluding positions surrounding the outflow associated with BN/KL and IRc2, display integrated intensities that correlate strongly with known cloud surface tracers such as CN, C2H, 13CO J =5-4, and HCN, and less well with the volume tracer N2H+. Moreover, at total column densities corresponding to Av < 15 mag., the ratio of H2O to C18O integrated intensities shows a clear rise approaching the cloud surface. We show that this behavior cannot be accounted for by either optical depth or excitation effects, but suggests that gas-phase water abundances fall at large Av. These results are important as they affect measures of the true water-vapor abundance in molecular clouds by highlighting the limitations...

  18. Corrosion detection and monitoring in steam generators by means of ultrasound; Deteccion y monitoreo de corrosion por medio de ultrasonido en generadores de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Chacon Nava, Jose G.; Calva, Mauricio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Fuentes Samaniego, Raul [Universidad Autonoma de Nuevo Leon (Mexico); Peraza Garcia, Alejandro [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    The tube and component failures in steam generators due to corrosion cause huge economical losses. In this article the internal corrosion processes (hydrogen attack) and high temperature corrosion are described, as well as the ultrasound techniques used for its detection. The importance of obtaining corrosion rates, which are fundamental parameters for the detection of the tube`s residual life. The purpose is to prevent possible failures that would diminish the power plant availability. [Espanol] Las fallas de tuberia en componentes de generadores de vapor debidas a corrosion ocasionan considerables perdidas economicas. En este articulo se describen los procesos de corrosion interna (ataque por hidrogeno) y corrosion en alta temperatura, asi como tecnicas de ultrasonido empleadas para su deteccion. Se destaca la importancia de obtener valores de velocidad de corrosion, que es un parametro fundamental para la determinacion de la vida residual de tuberias. El proposito es poder prevenir posibles fallas que disminuyan la disponibilidad de centrales termoelectricas.

  19. Fractured-rock hydrogeophysics with electrically conductive and neutrally buoyant tracers

    Science.gov (United States)

    Shakas, A.; Linde, N.; Baron, L.; Le Borgne, T.; Bour, O.; Lavenant, N.; Gerard, M. F.

    2016-12-01

    Artificial tracer tests help to characterize and understand the dynamics of groundwater systems. This remains a challenging task, especially when dealing with highly heterogeneous formations in which flow can be very localized and the interpretation of tracer breakthrough curves may be ambiguous. As a complement to tracer tests, ground-penetrating radar (GPR) and electrical resistivity tomography can map the space-time migration of electrically conductive tracers. In hydrogeophysics, the most common tracer is dissolved table salt in water. However, conventional salt tracers lead to density effects that are often ignored. Even less than 1% density variations can have a dramatic effect on transport behavior and affect tracer tests in complex ways. Such effects have been demonstrated in our previous experiments that used single-hole GPR to monitor saline push-pull tests in fractured granite. It is possible to model density effects, but this leads to computational complexity and field dynamics that are not necessarily representative of the natural responses of the system. To minimize density effects, we performed a new set of push-pull tests using a neutrally buoyant and electrically conductive tracer at the same test site located close to Ploemeur, France. This novel tracer consists of a mixture of salt (NaCl), water and pure ethanol. Ethanol has a density of 789 g/L at 20° C and is used to counter-act the salt-induced density increase. Our GPR time-lapse images and tracer breakthrough data indicate a largely reversible transport process that confirms the neutral buoyancy of the tracer. Ethanol is biodegradable and does not pose significant environmental issues. Furthermore, calibration of the neutral-buoyant mixture is straightforward to perform in the field using Archimedes principle. Based on these results, we argue that neutrally buoyant ethanol-salt-water mixtures are ideal for a wide variety of hydrogeophysical tracer tests in porous or fractured media.

  20. Monitoring System for Atmospheric Water Vapor with a Ground-Based Multi-Band Radiometer: Meteorological Application of Radio Astronomy Technologies

    Science.gov (United States)

    Nagasaki, T.; Araki, K.; Ishimoto, H.; Kominami, K.; Tajima, O.

    2016-08-01

    High-resolution estimation of thermodynamic properties in the atmosphere can help to predict and mitigate meteorological disasters, such as local heavy rainfall and tornadic storms. For the purposes of short-term forecasting and nowcasting of severe storms, we propose a novel ground-based measurement system, which observes the intensity of atmospheric radiation in the microwave range. Our multi-band receiver system is designed to identify a rapid increase in water vapor before clouds are generated. At frequencies between 20 and 30 GHz, our system simultaneously measures water vapor as a broad absorption peak at 22 GHz as well as cloud liquid water. Another band at 50-60 GHz provides supplementary information from oxygen radiation to give vertical profiles of physical temperature. For the construction of this cold receiver system, novel technologies originally developed for observations of cosmic microwave background radiation were applied. The input atmospheric signal is amplified by a cold low-noise amplifier maintained below 10 K, while the spectrum of this amplified signal is measured using a signal analyzer under ambient conditions. The cryostat also contains a cold black body at 40 K to act as a calibration signal. This calibration signal is transported to each of the receivers via a wire grid. We can select either the atmospheric signal or the calibration signal by changing the orientation of this wire. Each receiver can be calibrated using this setup. Our system is designed to be compact (<1 m3), with low power consumption (˜ 1.5 kW). Therefore, it is easy to deploy on top of high buildings, mountains, and ship decks.

  1. Polyethyleneimine as tracer for electron microscopy

    NARCIS (Netherlands)

    Schurer, Jacob Willem

    1980-01-01

    In this thesis the development of a tracer particle for use in electron microscopy is described. Attempts were made to use this tracer particle in immuno-electron microscopy and to trace negatively charged tissue components. ... Zie: Summary

  2. Application of ethanol as a geothermal tracer: a field-test in the Los Azufres geothermal field, Michoacan, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Tello Hinojosa, Enrique [Comision Federal de Electricidad, Morelia, Michoacan (Mexico); Pal Verma, Mahendra [Comision Federal de Electricidad, Morelia, Michoacan (Mexico); Suarez Arriaga, Mario C. [Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan (Mexico); Barrera Conzalez, Victor; Sandoval Medina, Fernando [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    2005-12-01

    The thermal decomposition rate of ethanol, rhodamine WT and fluoroscein was determined from laboratory data obtained under conditions of temperature and pressure that simulated a geothermal reservoir. It was found that ethylic alcohol had better thermal stability rhodamine and fluoroscein. Using data obtained from de-ionized water experiments after 168 hours and 200 degree centigrade of temperature, the rhodamine WT and fluoroscein presented a degradation of 99.4% and 99.7%, respectively, while for the ethanol the degradation percentage under the same conditions was only of 44.6%. According to this, ethylic alcohol can be used as a conservative tracer up to about 250 degree centigrade, while rhodamine WT and fluoroscein can be used only at less than 200 degree centigrade, and only where the transit return time is expected to be less than 7 days. Ethanol was used as a conservative tracer in a field test in the southern zone of the Los Azufres geothermal field. The highest concentration was detected in a monitoring well in the steam phase 15 days after the injection, and in the liquid phase, or brine, 34 days after the injection. This suggests that alcohol fractionates preferentially in the steam phase and moves or migrates twice as fast than it does in the liquid phase. The tracer speed can be calculated in 176 m/day in the steam phase and 77.5 m/day in the brine. The ethanol presents good enough characteristics to be used as a tracer in both phases in geothermal environments. [Spanish] Se determino la velocidad de descomposicion termica del etanol, la rodamina y la fluoresceina a partir de datos de laboratorio obtenidos bajo condiciones de presion y de temperatura que simulan las de un yacimiento geotermico. Se encontro que el alcohol etilico presenta una mayor estabilidad termica que la rodamina y la fluoresceina. Empleando los datos obtenidos de experimentos con agua de-ionizada despues de 168 horas y a 200 grados centigrados de temperatura, la rodamina y la

  3. Tracer-tracer relations as a tool for research on polar ozone loss

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Rolf

    2010-07-01

    The report includes the following chapters: (1) Introduction: ozone in the atmosphere, anthropogenic influence on the ozone layer, polar stratospheric ozone loss; (2) Tracer-tracer relations in the stratosphere: tracer-tracer relations as a tool in atmospheric research; impact of cosmic-ray-induced heterogeneous chemistry on polar ozone; (3) quantifying polar ozone loss from ozone-tracer relations: principles of tracer-tracer correlation techniques; reference ozone-tracer relations in the early polar vortex; impact of mixing on ozone-tracer relations in the polar vortex; impact of mesospheric intrusions on ozone-tracer relations in the stratospheric polar vortex calculation of chemical ozone loss in the arctic in March 2003 based on ILAS-II measurements; (4) epilogue.

  4. Development and application of a modified wireless tracer for disaster prevention

    Science.gov (United States)

    Chung Yang, Han; Su, Chih Chiang

    2016-04-01

    Typhoon-induced flooding causes water overflow in a river channel, which results in general and bridge scour and soil erosion, thus leading to bridge failure, debris flow and landslide collapse. Therefore, dynamic measurement technology should be developed to assess scour in channels and landslide as a disaster-prevention measure against bridge failure and debris flow. This paper presents a wireless tracer that enables monitoring general scour in river channels and soil erosion in hillsides. The wireless tracer comprises a wireless high-power radio modem, various electronic components, and a self-designed printed circuit board that are all combined with a 9-V battery pack and an auto switch. The entire device is sealed in a jar by silicon. After it was modified, the wireless tracer underwent the following tests for practical applications: power continuation and durability, water penetration, and signal transmission during floating. A regression correlation between the wireless tracer's transmission signal and distance was also established. This device can be embedded at any location where scouring is monitored, and, in contrast to its counterparts that detect scour depth by identifying and analyzing received signals, it enables real-time observation of the scouring process. In summary, the wireless tracer developed in this study provides a dynamic technology for real-time monitoring of scouring (or erosion) and forecasting of landslide hazards. Keywords: wireless tracer; scour; real-time monitoring; landslide hazard.

  5. Tracer diffusion inside fibrinogen layers

    Science.gov (United States)

    Cieśla, Michał; Gudowska-Nowak, Ewa; Sagués, Francesc; Sokolov, Igor M.

    2014-01-01

    We investigate the obstructed motion of tracer (test) particles in crowded environments by carrying simulations of two-dimensional Gaussian random walk in model fibrinogen monolayers of different orientational ordering. The fibrinogen molecules are significantly anisotropic and therefore they can form structures where orientational ordering, similar to the one observed in nematic liquid crystals, appears. The work focuses on the dependence between level of the orientational order (degree of environmental crowding) of fibrinogen molecules inside a layer and non-Fickian character of the diffusion process of spherical tracer particles moving within the domain. It is shown that in general particles motion is subdiffusive and strongly anisotropic, and its characteristic features significantly change with the orientational order parameter, concentration of fibrinogens, and radius of a diffusing probe.

  6. Tracer diffusion inside fibrinogen layers

    CERN Document Server

    Cieśla, Michał; Sagués, Francesc; Sokolov, Igor M

    2013-01-01

    We investigate the motion of tracer (test) particles in crowded environments by carrying simulations of two-dimensional Gaussian random walk in model fibrinogen monolayers of different orientational ordering. The fibrinogen molecules are significantly anisotropic and therefore they can form structures where orientational ordering, similar to the one observed in nematic liquid crystals, appears. The work focuses on the dependence between level of the orientational order (degree of environmental crowding) of fibrinogen molecules inside a layer and non-Fickian character of the diffusion process of spherical tracer particles moving within the domain. It is shown that in general particles motion is subdiffusive and strongly anisotropic, and its characteristic features significantly change with the orientational order parameter, concentration of fibrinogens and radius of a diffusing probe.

  7. Sensitivity of chemical tracers to meteorological parameters in the MOZART-3 chemical transport model

    Science.gov (United States)

    Kinnison, D. E.; Brasseur, G. P.; Walters, S.; Garcia, R. R.; Marsh, D. R.; Sassi, F.; Harvey, V. L.; Randall, C. E.; Emmons, L.; Lamarque, J. F.; Hess, P.; Orlando, J. J.; Tie, X. X.; Randel, W.; Pan, L. L.; Gettelman, A.; Granier, C.; Diehl, T.; Niemeier, U.; Simmons, A. J.

    2007-10-01

    The Model for Ozone and Related Chemical Tracers, version 3 (MOZART-3), which represents the chemical and physical processes from the troposphere through the lower mesosphere, was used to evaluate the representation of long-lived tracers and ozone using three different meteorological fields. The meteorological fields are based on (1) the Whole Atmosphere Community Climate Model, version 1b (WACCM1b), (2) the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis, and (3) a new reanalysis for year 2000 from ECMWF called EXP471. Model-derived tracers (methane, water vapor, and total inorganic nitrogen) and ozone are compared to data climatologies from satellites. Model mean age of air was also derived and compared to in situ CO2 and SF6 data. A detailed analysis of the chemical fields simulated by MOZART-3 shows that even though the general features characterizing the three dynamical sets are rather similar, slight differences in winds and temperature can produce substantial differences in the calculated distributions of chemical tracers. The MOZART-3 simulations that use meteorological fields from WACCM1b and ECMWF EXP471 represented best the distribution of long-lived tracers and mean age of air in the stratosphere. There was a significant improvement using the ECMWF EXP471 reanalysis data product over the ECMWF operational data product. The effect of the quasi-biennial oscillation circulation on long-lived tracers and ozone is examined.

  8. The fluorescent tracer experiment on Holiday Beach near Mugu Canyon, Southern California

    Science.gov (United States)

    Kinsman, Nicole; Xu, J. P.

    2012-01-01

    After revisiting sand tracer techniques originally developed in the 1960s, a range of fluorescent coating formulations were tested in the laboratory. Explicit steps are presented for the preparation of the formulation evaluated to have superior attributes, a thermoplastic pigment/dye in a colloidal mixture with a vinyl chloride/vinyl acetate copolymer. In September 2010, 0.59 cubic meters of fluorescent tracer material was injected into the littoral zone about 4 kilometers upcoast of Mugu submarine canyon in California. The movement of tracer was monitored in three dimensions over the course of 4 days using manual and automated techniques. Detailed observations of the tracer's behavior in the coastal zone indicate that this tracer successfully mimicked the native beach sand and similar methods could be used to validate models of tracer movement in this type of environment. Recommendations including how to time successful tracer studies and how to scale the field of view of automated camera systems are presented along with the advantages and disadvantages of the described tracer methodology.

  9. Tracer Modeling with the Hybrid Coordinates Ocean Model (hycom)

    Science.gov (United States)

    Garraffo, Z. D.; Kim, H.; Li, B.; Mehra, A.; Rivin, I.; Spindler, T.; Tolman, H. L.

    2012-12-01

    A series of tracer simulations have been started at NCEP/NWS aiming to a variety of applications, from dispersion of contaminants in estimations motivated by the Japanese nuclear accident near Fukushima, to nutrient estimations. The tracer capabilities of HYCOM are used, in regional domains, nested to daily nowcast/forecast fields from 1/12 HYCOM (RTOFS-Global) model output. A Fukushima Cs-137 simulation is now run in operational mode (RTOFS_ET). The simulation was initialized at the time of the Fukushima nuclear accident, and includes atmospheric deposition of Cs-137 and coastal discharge from a high resolution coastal model (ROMS done at NOAA/NOS). Almost all tracer moved offshore before the end of the first year after the accident. The tracer initially deposited in the Pacific ocean through the atmosphere slowly moves eastward and to deeper waters following the 3D ocean circulation. A series of simulations were started for nutrient estimations in the Gulf Stream and Mid Atlantic Bight region. Initially the capabilities implemented in HYCOM are used. The work aims to monitoring nutrients in the chosen region. Work is done in collaboration with Victoria Coles of U. Maryland.

  10. Tracer-Encapsulated Solid Pellet (TESPEL) Injection System for the TJ-II Stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, N. [National Institute for Fusion Science, Toki, Japan; McCarthy, K. J. [EURATOM-CIEMAT, Madrid, Spain; Hayashi, H. [National Institute for Fusion Science, Toki, Japan; Combs, Stephen Kirk [ORNL; Foust, Charles R [ORNL; Garcia, R. [Laboratory Nacional de Fusion, Madrid, Spain; Panadero, N. [CIEMAT, Laboratory Nacional de Fusion, Spain; Pawelec, E. [Opole University, Poland; Sanchez, J. Hernandez [Laboratory Nacional de Fusion, Madrid, Spain; Navarro, M. [CIEMAT, Laboratory Nacional de Fusion, Spain; Soleto, A. [CIEMAT, Laboratory Nacional de Fusion, Spain

    2016-01-01

    A tracer-encapsulated solid pellet (TESPEL) injection system for the TJ-II stellarator was recently developed. In order to reduce the time and cost for the development, we combined a TESPEL injector provided by National Institute for Fusion Science with an existing TJ-II cryogenic pellet injection system. Consequently, the TESPEL injection into the TJ-II plasma was successfully achieved, which was confirmed by several pellet diagnostics including a normal-incidence spectrometer for monitoring a tracer impurity behavior.

  11. Fractionation in position-specific isotope composition during vaporization of environmental pollutants measured with isotope ratio monitoring by ¹³C nuclear magnetic resonance spectrometry.

    Science.gov (United States)

    Julien, Maxime; Parinet, Julien; Nun, Pierrick; Bayle, Kevin; Höhener, Patrick; Robins, Richard J; Remaud, Gérald S

    2015-10-01

    Isotopic fractionation of pollutants in terrestrial or aqueous environments is a well-recognized means by which to track different processes during remediation. As a complement to the common practice of measuring the change in isotope ratio for the whole molecule using isotope ratio monitoring by mass spectrometry (irm-MS), position-specific isotope analysis (PSIA) can provide further information that can be exploited to investigate source and remediation of soil and water pollutants. Position-specific fractionation originates from either degradative or partitioning processes. We show that isotope ratio monitoring by (13)C NMR (irm-(13)C NMR) spectrometry can be effectively applied to methyl tert-butylether, toluene, ethanol and trichloroethene to obtain this position-specific data for partitioning. It is found that each compound exhibits characteristic position-specific isotope fractionation patterns, and that these are modulated by the type of evaporative process occurring. Such data should help refine models of how remediation is taking place, hence back-tracking to identify pollutant sources.

  12. Tracer tests in geothermal resource management

    Directory of Open Access Journals (Sweden)

    Axelsson G.

    2013-05-01

    Full Text Available Geothermal reinjection involves injecting energy-depleted fluid back into geothermal systems, providing an effective mode of waste-water disposal as well as supplementary fluid recharge. Cooling of production boreholes is one of the main disadvantages associated with reinjection, however. Tracer testing is an important tool for reinjection studies because tracer tests actually have a predictive power since tracer transport is orders of magnitude faster than cold-front advancement around reinjection boreholes. A simple and efficient method of tracer test interpretation, assuming specific flow channels connecting reinjection and production boreholes, is available. It simulates tracer return profiles and estimates properties of the flow channels, which are consequently used for predicting the production borehole cooling. Numerous examples are available worldwide on the successful application of tracer tests in geothermal management, many involving the application of this interpretation technique. Tracer tests are also used for general subsurface hydrological studies in geothermal systems and for flow rate measurements in two-phase geothermal pipelines. The tracers most commonly used in geothermal applications are fluorescent dyes, chemical substances and radioactive isotopes. New temperature-resistant tracers have also been introduced and high-tech tracers are being considered.

  13. The first steam continuous injection monitoring through the 4-D seismic in Brazil; Primeiro monitoramento de injecao continua de vapor atraves de sismica 4D no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Frederico Aguiar Ferreira; Farias, Armando Lopes; Silva, Leodilson Goes da; Rocha, Vivaldo Andrade [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    1999-07-01

    The 4 D seismic consists of the repetition of the tri dimensional seismic surveys with the aim of observing the differences in the reservoir acoustic behavior, provoked by the fluid movement and/or advances of heat and pressure fronts through the time. The fourth dimension is the time. This technology has a great potential in the reservoir management, because it is the first technology that allows the tri dimensional visualization of the dynamic processes. Aiming to monitoring a pilot project of steam continuous injection, the PETROBRAS - a Brazilian organization devoted to the petroleum exploration -, achieved two tri dimensional seismic surveys in the Alto do Rodrigues Field. This project represents the first application of the 4 D seismic in the Brazilian basins.

  14. Analysis of strain relaxation process in GaInN/GaN heterostructure by in situ X-ray diffraction monitoring during metalorganic vapor-phase epitaxial growth

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Daisuke; Kondo, Yasunari; Sowa, Mihoko; Sugiyama, Toru; Iwaya, Motoaki; Takeuchi, Tetsuya; Kamiyama, Satoshi [Faculty of Science and Technology, Meijo University, Nagoya 468-8502 (Japan); Akasaki, Isamu [Faculty of Science and Technology, Meijo University, Nagoya 468-8502 (Japan); Akasaki Research Center, Nagoya University, Nagoya 464-8603 (Japan)

    2013-03-15

    Strain relaxation in a GaInN/GaN heterostructure is analyzed by combining in situ X-ray diffraction (XRD) monitoring and ex situ observations. Two different characteristic thicknesses of GaInN films are defined by the evolution of in situ XRD from the full width at half-maximum of symmetric (0002) diffraction as a function of GaInN thickness. This in situ XRD measurement enables to clearly observe the critical thicknesses corresponding to strain relaxation in the GaInN/GaN heterostructure caused by the formation of surface pits with bent threading dislocations and the generation of misfit dislocations on GaInN during growth. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Dual signature tracer: A new tool for soil management and research.

    Science.gov (United States)

    Poleykett, Jack; Quinton, John; Armstrong, Alona; Maher, Barbara; Black, Kevin

    2015-04-01

    The significant detrimental effects that occur, both on and off site due to the transport of soil are well documented. Now more than ever, it is vital to understand the pathways, processes and fate of transported sediments, to underpin environmental strategy and develop robust forecast models. Researchers have employed a broad range of materials and techniques to trace the movement of soil through space and time. However, three primary challenges still remain: 1) to develop a tracer that has the same or similar hydraulic characteristics as soil: 2) to develop a tracer able to replicate the broad and variable particle size distribution of soils; and: 3) to develop a tracing methodology that increases the volume, and quality of data collected from the field. This study approaches these challenges using a unique 'dual signature' tracer comprising natural mineral material directly coated with a fluorescent dye pigment and loaded during coating with a naturally occurring magnetic mineral oxide creating a tracer with both fluorescent properties and para-magnetic character. An assessment of the effectiveness of the tracer as a tracer of soil was conducted at the soil box and plot scale under controlled rainfall conditions, to: 1) examine the behaviour of the tracer, and: 2) to assess the efficiency of the different tools available to monitor the tracer post- deployment. At the plot scale, a unique site specific tracer was developed to match the hydraulic characteristics (particle size distribution and specific gravity), of the native soil enabling the source-sink relationship, transport pathways and transport rate through the environment to be investigated. Spatial mapping of the tracer distribution within each plot was also conducted using photography and Ultra Violet (UV) illumination. The results of this study provide the basis for the development of a unique soil tracing methodology, which can be applied to investigate soil transport processes, at a range of scales in

  16. Tracer tests in geothermal resource management

    OpenAIRE

    Axelsson G.

    2013-01-01

    Geothermal reinjection involves injecting energy-depleted fluid back into geothermal systems, providing an effective mode of waste-water disposal as well as supplementary fluid recharge. Cooling of production boreholes is one of the main disadvantages associated with reinjection, however. Tracer testing is an important tool for reinjection studies because tracer tests actually have a predictive power since tracer transport is orders of magnitude faster than cold-front advancement around reinj...

  17. User’s Guide: Vapor Intrusion Estimation Tool for Unsaturated Zone Contaminant Sources

    Science.gov (United States)

    2016-08-30

    Mark Brusseau, University of Arizona Michelle Simon, US Environmental Protection Agency Pacific Northwest National Laboratory - 902 Battelle Blvd...is unlimited. The overall objective of this project is to demonstrate that the vapor-phase mass discharge test and vapor-phase tomography can...be neglected in favor of direct entry of Qs (e.g., for a porous foundation scenario or based on measurements from tracer tests ). )ln()ln( cc c g v

  18. Tracer-Test Planning Using the Efficient Hydrologic Tracer-Test Design (Ehtd) Program (2003)

    Science.gov (United States)

    Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test ...

  19. Ice-affected streamflow records using tracer-dilution discharge methods

    Science.gov (United States)

    Capesius, J.P.; Sullivan, J.R.; Williams, C.A.; O'Neill, G. B.; ,

    2002-01-01

    Accurate ice-affected streamflow records are difficult to obtain for several reasons. Problems measuring stage, variable backwater conditions, access limitations in wintertime, and problems measuring flowing water under ice cover all contribute to make ice-affected streamflow records less accurate than open-channel streamflow records. The inaccuracy of ice-affected streamflow records is particularly troublesome for small streams where Instream-Flow water rights exist. The Colorado Water Conservation Board uses these water rights to protect in-stream aquatic communities. In January and February 2002, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, conducted an experiment using a sodium chloride tracer to determine streamflow under ice cover. The purpose of this study is to determine the usefulness and accuracy of ice-affected streamflow records using a sodium chloride tracer that was automatically injected into the stream. The tracer was injected at two gaging stations once per day for up to 25 days. Multiple-parameter water-quality sensors at the two gaging stations monitored background and peak tracer concentrations and conductance. These data were used to determine discharge at each site. A comparison of current-meter measurements to tracer-dilution discharge measurements shows an underestimation of discharge due to inaccuracy of current-meter measurements with ice cover and inconsistent tracer-pump rates caused by partial freezing of the tracer solution in the injection lines.

  20. Aviation Fuel Tracer Simulation: Model Intercomparison and Implications

    Science.gov (United States)

    Danilin, M. Y.; Fahey, D. W.; Schumann, U.; Prather, M. J.; Penner, J. E.; Ko, M. K. W.; Weisenstein, D. K.; Jackman, C. H.; Pitari, G.; Koehler, I.; Sausen, R.; Weaver, C. J.; Douglass, A. R.; Connell, P. S.; Kinnison, D. E.; Dentener, F. J.; Fleming, E. L.; Berntsen, T. K.; Isaksen, I. S. A.

    1998-01-01

    An upper limit for aircraft-produced perturbations to aerosols and gaseous exhaust products in the upper troposphere and lower stratosphere (UT/LS) is derived using the 1992 aviation fuel tracer simulation performed by eleven global atmospheric models. Key findings are that subsonic aircraft emissions: (1) have not been responsible for the observed water vapor trends at 40degN; (2) could be a significant source of soot mass near 12 km, but not at 20 km; (3) might cause a noticeable increase in the background sulfate aerosol surface area and number densities (but not mass density) near the northern mid-latitude tropopause; and (4) could provide a global, annual mean top of the atmosphere radiative forcing up to +0.006 W/sq m and -0.013 W/sq m due to emitted soot and sulfur, respectively.

  1. Tracers for Characterizing Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karen Wright; George Redden; Carl D. Palmer; Harry Rollins; Mark Stone; Mason Harrup; Laurence C. Hull

    2010-02-01

    Information about the times of thermal breakthrough and subsequent rates of thermal drawdown in enhanced geothermal systems (EGS) is necessary for reservoir management, designing fracture stimulation and well drilling programs, and forecasting economic return. Thermal breakthrough in heterogeneous porous media can be estimated using conservative tracers and assumptions about heat transfer rates; however, tracers that undergo temperature-dependent changes can provide more detailed information about the thermal profile along the flow path through the reservoir. To be effectively applied, the thermal reaction rates of such temperature sensitive traces must be well characterized for the range of conditions that exist in geothermal systems. Reactive tracers proposed in the literature include benzoic and carboxylic acids (Adams) and organic esters and amides (Robinson et al.); however, the practical temperature range over which these tracers can be applied (100-275°C) is somewhat limited. Further, for organic esters and amides, little is known about their sorption to the reservoir matrix and how such reactions impact data interpretation. Another approach involves tracers where the reference condition is internal to the tracer itself. Two examples are: 1) racemization of polymeric amino acids, and 2) mineral thermoluminescence. In these cases internal ratios of states are measured rather than extents of degradation and mass loss. Racemization of poly-L-lactic acid (for example) is temperature sensitive and therefore can be used as a temperature-recording tracer depending on the rates of racemization and stability of the amino acids. Heat-induced quenching of thermoluminescence of pre-irradiated LiF can also be used. To protect the tracers from alterations (extraneous reactions, dissolution) in geothermal environments we are encapsulating the tracers in core-shell colloidal structures that will subsequently be tested for their ability to be transported and to protect the

  2. Tracers for Characterizing Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karen Wright; George Redden; Carl D. Palmer; Harry Rollins; Mark Stone; Mason Harrup; Laurence C. Hull

    2010-02-01

    Information about the times of thermal breakthrough and subsequent rates of thermal drawdown in enhanced geothermal systems (EGS) is necessary for reservoir management, designing fracture stimulation and well drilling programs, and forecasting economic return. Thermal breakthrough in heterogeneous porous media can be estimated using conservative tracers and assumptions about heat transfer rates; however, tracers that undergo temperature-dependent changes can provide more detailed information about the thermal profile along the flow path through the reservoir. To be effectively applied, the thermal reaction rates of such temperature sensitive traces must be well characterized for the range of conditions that exist in geothermal systems. Reactive tracers proposed in the literature include benzoic and carboxylic acids (Adams) and organic esters and amides (Robinson et al.); however, the practical temperature range over which these tracers can be applied (100-275°C) is somewhat limited. Further, for organic esters and amides, little is known about their sorption to the reservoir matrix and how such reactions impact data interpretation. Another approach involves tracers where the reference condition is internal to the tracer itself. Two examples are: 1) racemization of polymeric amino acids, and 2) mineral thermoluminescence. In these cases internal ratios of states are measured rather than extents of degradation and mass loss. Racemization of poly-L-lactic acid (for example) is temperature sensitive and therefore can be used as a temperature-recording tracer depending on the rates of racemization and stability of the amino acids. Heat-induced quenching of thermoluminescence of pre-irradiated LiF can also be used. To protect the tracers from alterations (extraneous reactions, dissolution) in geothermal environments we are encapsulating the tracers in core-shell colloidal structures that will subsequently be tested for their ability to be transported and to protect the

  3. RGD-based PET tracers for imaging receptor integrin αv β3 expression.

    Science.gov (United States)

    Cai, Hancheng; Conti, Peter S

    2013-05-15

    Positron emission tomography (PET) imaging of receptor integrin αv β3 expression may play a key role in the early detection of cancer and cardiovascular diseases, monitoring disease progression, evaluating therapeutic response, and aiding anti-angiogenic drugs discovery and development. The last decade has seen the development of new PET tracers for in vivo imaging of integrin αv β3 expression along with advances in PET chemistry. In this review, we will focus on the radiochemistry development of PET tracers based on arginine-glycine-aspartic acid (RGD) peptide, present an overview of general strategies for preparing RGD-based PET tracers, and review the recent advances in preparations of (18) F-labeled, (64) Cu-labeled, and (68) Ga-labeled RGD tracers, RGD-based PET multivalent probes, and RGD-based PET multimodality probes for imaging receptor integrin αv β3 expression.

  4. Graphical Analysis of PET Data Applied to Reversible and Irreversible Tracers

    Energy Technology Data Exchange (ETDEWEB)

    Logan, Jean

    1999-11-18

    Graphical analysis refers to the transformation of multiple time measurements of plasma and tissue uptake data into a linear plot, the slope of which is related to the number of available tracer binding sites. This type of analysis allows easy comparisons among experiments. No particular model structure is assumed, however it is assumed that the tracer is given by bolus injection and that both tissue uptake and the plasma concentration of unchanged tracer are monitored following tracer injection. The requirement of plasma measurements can be eliminated in some cases when a reference region is available. There are two categories of graphical methods which apply to two general types of ligands--those which bind reversibly during the scanning procedure and those which are irreversible or trapped during the time of the scanning procedure.

  5. The Accurate Particle Tracer Code

    CERN Document Server

    Wang, Yulei; Qin, Hong; Yu, Zhi

    2016-01-01

    The Accurate Particle Tracer (APT) code is designed for large-scale particle simulations on dynamical systems. Based on a large variety of advanced geometric algorithms, APT possesses long-term numerical accuracy and stability, which are critical for solving multi-scale and non-linear problems. Under the well-designed integrated and modularized framework, APT serves as a universal platform for researchers from different fields, such as plasma physics, accelerator physics, space science, fusion energy research, computational mathematics, software engineering, and high-performance computation. The APT code consists of seven main modules, including the I/O module, the initialization module, the particle pusher module, the parallelization module, the field configuration module, the external force-field module, and the extendible module. The I/O module, supported by Lua and Hdf5 projects, provides a user-friendly interface for both numerical simulation and data analysis. A series of new geometric numerical methods...

  6. Bacteriophages as surface and ground water tracers

    Directory of Open Access Journals (Sweden)

    P. Rossi

    1998-01-01

    Full Text Available Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra. In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  7. Bacteriophages as surface and ground water tracers

    Science.gov (United States)

    Rossi, P.; Dörfliger, N.; Kennedy, K.; Müller, I.; Aragno, M.

    Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra). In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  8. The Copenhagen tracer experiments: Reporting of measurements

    DEFF Research Database (Denmark)

    Gryning, Sven-Erik; Lyck, E.

    2002-01-01

    buoyancy from a tower at a height of 115 meters and then collected 2-3 meters above ground-level at positions in up to three crosswind arcs of tracer sampling units, positioned 2-6 km from the point of release. Three consecutive 20 min averaged tracer concentrations were measured, allowing for a total...

  9. Effect of tracer buoyancy on tracer experiments conducted in fractured crystalline bedrock

    Science.gov (United States)

    Becker, Matthew W.

    2003-02-01

    Tracer buoyancy has been shown to influence breakthrough from two-well tracer experiments conducted in porous media. Two-well tracer experiments are presented from fractured crystalline bedrock, in which the specific gravity of the tracer injectate varied from 1.0002 to 1.0133. Under the forced hydraulic conditions imposed, no difference in breakthrough was noted for the three experiments. These results show that even relatively dense tracer injectate solutions may have an insignificant effect on breakthrough when imposed gradients are sufficiently large.

  10. The Art of Tomographic Tracer Tests

    Science.gov (United States)

    Cirpka, O. A.; Leven, C.; Doro, K. O.; Sanchez-Leon, E. E.

    2015-12-01

    In tracer tomography several tracer tests are performed within an aquifer and breakthrough curves are observed at multiple observation points. In the analysis, hydraulic conductivity is estimated as spatially variable, 3-D field subject to some smoothness constraint. Coupled flow and transport models using this conductivity fields are requested to meet observed tracer data. The approach can be combined with hydraulic tomography.We have performed hydraulic-tomography and tracer-tomography tests using heat and fluorescein as tracers at a field site close to Tübingen, Germany. The aquifer consists of 8-9m alluvials sands and gravels overlain by 1-2m alluvial fines. The hydraulic setup consists of a forced flow field between an injection/extraction well couple, embedded in the forced flow field of another well couple. By turning injection to extraction wells, and vice versa, two different flow fields were considered. Injection wells were separated into several sections by packers, and water was injected into each section proportional to its transmissivity. The water injected into one of the sections contained the tracer. Multi-level observation wells were equiped with thermometers (for heat-tracer tests), on-line fluoremeters (for teh dye tracers), and pressure transducers. Processing of the breakthrough curves included data cleaning, non-parametric deconvolution, and calculation of temperal moments of the estimated transfer functions.The joint inversion of hydraulic-head measurements and temporal moments of heat-tracer transfer functions was done by the quasi-linear geostatistical approach on a computing cluster. As alternative, we directly invert the time series (without temporal moments) by Ensemble-Kalman filtering.The high diffusion coefficient of temperature diminishes the penetration of the heat-tracer into the aquifer, which can partially be compensated by reverting the flow field and repeating the tracer tests. In tests with fluorscent tracers the signal

  11. Three-Dimensional Bayesian Geostatistical Aquifer Characterization at the Hanford 300 Area using Tracer Test Data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xingyuan; Murakami, Haruko; Hahn, Melanie S.; Hammond, Glenn E.; Rockhold, Mark L.; Zachara, John M.; Rubin, Yoram

    2012-06-01

    Tracer testing under natural or forced gradient flow holds the potential to provide useful information for characterizing subsurface properties, through monitoring, modeling and interpretation of the tracer plume migration in an aquifer. Non-reactive tracer experiments were conducted at the Hanford 300 Area, along with constant-rate injection tests and electromagnetic borehole flowmeter (EBF) profiling. A Bayesian data assimilation technique, the method of anchored distributions (MAD) [Rubin et al., 2010], was applied to assimilate the experimental tracer test data with the other types of data and to infer the three-dimensional heterogeneous structure of the hydraulic conductivity in the saturated zone of the Hanford formation. In this study, the Bayesian prior information on the underlying random hydraulic conductivity field was obtained from previous field characterization efforts using the constant-rate injection tests and the EBF data. The posterior distribution of the conductivity field was obtained by further conditioning the field on the temporal moments of tracer breakthrough curves at various observation wells. MAD was implemented with the massively-parallel three-dimensional flow and transport code PFLOTRAN to cope with the highly transient flow boundary conditions at the site and to meet the computational demands of MAD. A synthetic study proved that the proposed method could effectively invert tracer test data to capture the essential spatial heterogeneity of the three-dimensional hydraulic conductivity field. Application of MAD to actual field data shows that the hydrogeological model, when conditioned on the tracer test data, can reproduce the tracer transport behavior better than the field characterized without the tracer test data. This study successfully demonstrates that MAD can sequentially assimilate multi-scale multi-type field data through a consistent Bayesian framework.

  12. IMAGE Project: Results of Laboratory Tests on Tracers for Supercritical Conditions.

    Science.gov (United States)

    Brandvoll, Øyvind; Opsahl Viig, Sissel; Nardini, Isabella; Muller, Jiri

    2016-04-01

    The use of tracers is a well-established technique for monitoring dynamic behaviour of water and gas through a reservoir. In geothermal reservoirs special challenges are encountered due to high temperatures and pressures. In this work, tracer candidates for monitoring water at supercritical conditions (temperature > 374°C, pressure ca 218 bar), are tested in laboratory experiments. Testing of tracers at supercritical water conditions requires experimental set-ups which tolerate harsh conditions with respect to high temperature and pressure. In addition stringent HES (health, environment and safety) factors have to be taken into consideration when designing and performing the experiments. The setup constructed in this project consists of a pressure vessel, high pressure pump, instrumentation for pressure and temperature control and instrumentation required for accurate sampling of tracers. In order to achieve accurate results, a special focus has been paid to the development of the tracer sampling technique. Perfluorinated cyclic hydrocarbons (PFCs) have been selected as tracer candidates. This group of compounds is today commonly used as gas tracers in oil reservoirs. According to the literature they are stable at temperatures up to 400°C. To start with, five PFCs have been tested for thermal stability in static experiments at 375°C and 108 bar in the experimental setup described above. The tracer candidates will be further tested for several months at the relevant conditions. Preliminary results indicate that some of the PFC compounds show stability after three months. However, in order to arrive at conclusive results, the experiments have to be repeated over a longer period and paying special attention to more accurate sampling procedures.

  13. Using the tracer-dilution discharge method to develop streamflow records for ice-affected streams in Colorado

    Science.gov (United States)

    Capesius, Joseph P.; Sullivan, Joseph R.; O'Neill, Gregory B.; Williams, Cory A.

    2005-01-01

    Accurate ice-affected streamflow records are difficult to obtain for several reasons, which makes the management of instream-flow water rights in the wintertime a challenging endeavor. This report documents a method to improve ice-affected streamflow records for two gaging stations in Colorado. In January and February 2002, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, conducted an experiment using a sodium chloride tracer to measure streamflow under ice cover by the tracer-dilution discharge method. The purpose of this study was to determine the feasibility of obtaining accurate ice-affected streamflow records by using a sodium chloride tracer that was injected into the stream. The tracer was injected at two gaging stations once per day for approximately 20 minutes for 25 days. Multiple-parameter water-quality sensors at the two gaging stations monitored background and peak chloride concentrations. These data were used to determine discharge at each site. A comparison of the current-meter streamflow record to the tracer-dilution streamflow record shows different levels of accuracy and precision of the tracer-dilution streamflow record at the two sites. At the lower elevation and warmer site, Brandon Ditch near Whitewater, the tracer-dilution method overestimated flow by an average of 14 percent, but this average is strongly biased by outliers. At the higher elevation and colder site, Keystone Gulch near Dillon, the tracer-dilution method experienced problems with the tracer solution partially freezing in the injection line. The partial freezing of the tracer contributed to the tracer-dilution method underestimating flow by 52 percent at Keystone Gulch. In addition, a tracer-pump-reliability test was conducted to test how accurately the tracer pumps can discharge the tracer solution in conditions similar to those used at the gaging stations. Although the pumps were reliable and consistent throughout the 25-day study period

  14. Using Tracer Technology to Characterize Contaminated Pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Maresca, Joseph, W., Jr., Ph.D.; Bratton, Wesley, L., Ph.D., P.E.; Dickerson, Wilhelmina; Hales, Rochelle

    2005-12-30

    The Pipeline Characterization Using Tracers (PCUT) technique uses conservative and partitioning, reactive or other interactive tracers to remotely determine the amount of contaminant within a run of piping or ductwork. The PCUT system was motivated by a method that has been successfully used to characterize subsurface soil contaminants and is similar in operation to that of a gas chromatography column. By injecting a ?slug? of both conservative and partitioning tracers at one end (or section) of the piping and measuring the time history of the concentration of the tracers at the other end (or another section) of the pipe, the presence, location, and amount of contaminant within the pipe or duct can be determined. The tracers are transported along the pipe or duct by a gas flow field, typically air or nitrogen, which has a velocity that is slow enough so that the partitioning tracer has time to interact with the contaminant before the tracer slug completely passes over the contaminate region. PCUT not only identifies the presence of contamination, it also can locate the contamination along the pipeline and quantify the amount of residual. PCUT can be used in support of deactivation and decommissioning (D&D) of piping and ducts that may have been contaminated with hazardous chemicals such as chlorinated solvents, petroleum products, radioactive materials, or heavy metals, such as mercury.

  15. Tracer design for magnetic particle imaging (invited).

    Science.gov (United States)

    Ferguson, R Matthew; Khandhar, Amit P; Krishnan, Kannan M

    2012-04-01

    Magnetic particle imaging (MPI) uses safe iron oxide nanoparticle tracers to offer fundamentally new capabilities for medical imaging, in applications as vascular imaging and ultra-sensitive cancer therapeutics. MPI is perhaps the first medical imaging platform to intrinsically exploit nanoscale material properties. MPI tracers contain magnetic nanoparticles whose tunable, size-dependent magnetic properties can be optimized by selecting a particular particle size and narrow size-distribution. In this paper we present experimental MPI measurements acquired using a homemade MPI magnetometer: a zero-dimensional MPI imaging system designed to characterize tracer performance by measuring the derivative of the time-varying tracer magnetization, M'(H(t)), at a driving frequency of 25 kHz. We show that MPI performance is optimized by selecting phase-pure magnetite tracers of a particular size and narrow size distribution; in this work, tracers with 20 nm median diameter, log-normal distribution shape parameter, σ(v), equal to 0.26, and hydrodynamic diameter equal to 30 nm showed the best performance. Furthermore, these optimized MPI tracers show 4 × greater signal intensity (measured at the third harmonic) and 20% better spatial resolution compared with commercial nanoparticles developed for MRI.

  16. Compartmental modeling and tracer kinetics

    CERN Document Server

    Anderson, David H

    1983-01-01

    This monograph is concerned with mathematical aspects of compartmental an­ alysis. In particular, linear models are closely analyzed since they are fully justifiable as an investigative tool in tracer experiments. The objective of the monograph is to bring the reader up to date on some of the current mathematical prob­ lems of interest in compartmental analysis. This is accomplished by reviewing mathematical developments in the literature, especially over the last 10-15 years, and by presenting some new thoughts and directions for future mathematical research. These notes started as a series of lectures that I gave while visiting with the Division of Applied ~1athematics, Brown University, 1979, and have developed in­ to this collection of articles aimed at the reader with a beginning graduate level background in mathematics. The text can be used as a self-paced reading course. With this in mind, exercises have been appropriately placed throughout the notes. As an aid in reading the material, the e~d of a ...

  17. AMTEC vapor-vapor series connected cells

    Science.gov (United States)

    Underwood, Mark L.; Williams, Roger M.; Ryan, Margaret A.; Nakamura, Barbara J.; Oconnor, Dennis E.

    1995-08-01

    An alkali metal thermoelectric converter (AMTEC) having a plurality of cells structurally connected in series to form a septum dividing a plenum into two chambers, and electrically connected in series, is provided with porous metal anodes and porous metal cathodes in the cells. The cells may be planar or annular, and in either case a metal alkali vapor at a high temperature is provided to the plenum through one chamber on one side of the wall and returned to a vapor boiler after condensation at a chamber on the other side of the wall in the plenum. If the cells are annular, a heating core may be placed along the axis of the stacked cells. This arrangement of series-connected cells allows efficient generation of power at high voltage and low current.

  18. Gasoline Vapor Recovery

    Science.gov (United States)

    1979-01-01

    Gasoline is volatile and some of it evaporates during storage, giving off hydrocarbon vapor. Formerly, the vapor was vented into the atmosphere but anti-pollution regulations have precluded that practice in many localities, so oil companies and storage terminals are installing systems to recover hydrocarbon vapor. Recovery provides an energy conservation bonus in that most of the vapor can be reconverted to gasoline. Two such recovery systems are shown in the accompanying photographs (mid-photo at right and in the foreground below). They are actually two models of the same system, although.configured differently because they are customized to users' needs. They were developed and are being manufactured by Edwards Engineering Corporation, Pompton Plains, New Jersey. NASA technological information proved useful in development of the equipment.

  19. Gasoline Reid Vapor Pressure

    Science.gov (United States)

    EPA regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season to reduce evaporative emissions from gasoline that contribute to ground-level ozone and diminish the effects of ozone-related health problems.

  20. Vapor Control Layer Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-09-08

    This information sheet describes the level of vapor control required on the interior side of framed walls with typical fibrous cavity insulation (fibreglass, rockwool, or cellulose, based on DOE climate zone of construction.

  1. Study of optical techniques for the Ames unitary wind tunnels. Part 2: Light sheet and vapor screen

    Science.gov (United States)

    Lee, George

    1992-01-01

    Light sheet and vapor screen methods have been studied with particular emphasis on those systems that have been used in large transonic and supersonic wind tunnels. The various fluids and solids used as tracers or light scatters and the methods for tracing generation have been studied. Light sources from high intensity lamps and various lasers have been surveyed. Light sheet generation and projection methods were considered. Detectors and location of detectors were briefly studied. A vapor screen system and a technique for location injection of tracers for the NASA Ames 9 by 7 foot Supersonic Wind Tunnel were proposed.

  2. Attenuation of concentration fluctuations of water vapor and other trace gases in turbulent tube flow

    DEFF Research Database (Denmark)

    Massman, W.J.; Ibrom, Andreas

    2008-01-01

    Recent studies with closed-path eddy covariance (EC) systems have indicated that the attenuation of fluctuations of water vapor concentration is dependent upon ambient relative humidity, presumably due to sorption/desorption of water molecules at the interior surface of the tube. Previous studies...... of EC-related tube attenuation effects have either not considered this issue at all or have only examined it superficially. Nonetheless, the attenuation of water vapor fluctuations is clearly much greater than might be expected from a passive tracer in turbulent tube flow. This study reexamines...... the turbulent tube flow issue for both passive and sorbing tracers with the intent of developing a physically-based semi-empirical model that describes the attenuation associated with water vapor fluctuations. Toward this end, we develop a new model of tube flow dynamics (radial profiles of the turbulent...

  3. Comparative evaluation of two sediment tracers in a rainfall simulation experiment

    Science.gov (United States)

    Strauss, Peter; Guzman, Gema; Mentler, Axel

    2015-04-01

    The use of sediment tracers tries to contribute to solving problems of traditional soil erosion measurements such as allocation of erosional and depositional areas. A number of different tracing approaches have already been established however, as none of available techniques are able to fully satisfy all the requirements for being an ideal tracer the search for alternative methods continues. Clays tagged with quaternary ammonium compounds are widely used in industry and are easy to incorporate into soils for sediment tracing experiments. To explore the potential of these clays a laboratory experiment was carried out in order to characterize their behaviour as compared to the well-established sediment tracer magnetic iron oxide. The experiment consisted of a simulated rainfall event of 60 mm/h in a box laboratory flume divided in two ridge-furrow subplots (200 x 57 cm). In order to evaluate transport and redistribution of soil from the ridges to the furrow and to measure the dynamic behaviour of the tracers during the rainfall a dense grid of soil samples was taken before and after the experiment (140 samples in total). Runoff and sediment were collected and all samples were analysed for both tracers. Results indicate the general suitability of organophilic clays to monitor soil redistribution by water erosion. The average relative contributions from shoulders and furrow to total sediment export determined by both tracers were similar and indicated a higher contribution from ridges. A key advantage of using organophilic clays is that the detection limit of organophilic clays is extremely low and the background concentration is zero. Despite the inherent differences between both tracers such as way of bounding, sediment enrichment or analytical technique, this experimental comparison of an established and more novel tracer method underscores the potential suitability of the latter for soil erosion studies.

  4. Characterization of thermal tracer tests and heat exchanges in fractured media

    Science.gov (United States)

    de La Bernardie, Jérôme; Bour, Olivier; Guihéneuf, Nicolas; Chatton, Eliot; Labasque, Thierry; Longuevergne, Laurent; Le Lay, Hugo; Koch, Florian; Gerard, Marie-Françoise; Lavenant, Nicolas; Le Borgne, Tanguy

    2016-04-01

    Geothermal energy is a renewable energy source particularly attractive due to associated low greenhouse gas emission rates. Crystalline rocks are in general considered of poor interest for geothermal applications at shallow depths (loop heat exchanger (standing column well). For doing so, several heat tracer tests have been achieved along a borehole between two connected fractures. The heat tracer tests have been achieved at the experimental site of Ploemeur (H+ observatory network). The tracer tests consist in monitoring the temperature in the upper fracture while injecting hot water in the deeper one thanks to a field boiler. For such an experimental setup, the main difficulty to interpret the data comes from the requirement for separating the temperature advective signal of the tracer test (temperature recovery) from the heat increase due to injection of hot water through the borehole which induces heat losses all along the injection tube in the water column. For doing so, in addition to a double straddle packer used for isolating the injection chamber, the particularity of the experimental set up is the use of fiber optic distributed temperature sensing (FO-DTS); an innovative technology which allows spatial and temporal monitoring of the temperature all along the well. Thanks to this tool, we were able to estimate heat increases coming from diffusion along the injection tube which is found much lower than localized temperature increases resulting from tracer test recovery. With local temperatures probes, separating both effects would not have been feasible. We also show through signal processing how diffusive and advective effects may be differentiated. This allowed us to estimate temperature recovery for different heat tracer durations and setups. In particular we show that temperature recovery is highly dependent on hydraulic configuration such as perfect dipole or fully convergent heat tracer tests.

  5. Heat tracer test in an alluvial aquifer: field experiment and inverse modelling

    Science.gov (United States)

    Klepikova, Maria; Wildemeersch, Samuel; Jamin, Pierre; Orban, Philippe; Hermans, Thomas; Nguyen, Frederic; Brouyère, Serge; Dassargues, Alain

    2016-04-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in the recovery well and in monitoring wells. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells distributed throughout the field site (space-filling arrangement) were used. Temperature breakthrough curves in observation wells are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. The observed complex behavior of the heat plume was explained by the groundwater flow gradient on the site and heterogeneity of hydraulic conductivity field. Moreover, due to high injection temperatures during the field experiment a temperature-induced fluid density effect on heat transport occurred. By using a flow and heat transport numerical model with variable density coupled with the pilot point inverse approach, main preferential flow paths were delineated.

  6. Estimates of tracer-based piston-flow ages of groundwater from selected sites-National Water-Quality Assessment Program, 1992-2005

    Science.gov (United States)

    Hinkle, Stephen R.; Shapiro, Stephanie D.; Plummer, L. Niel; Busenberg, Eurybiades; Widman, Peggy K.; Casile, Gerolamo C.; Wayland, Julian E.

    2011-01-01

    This report documents selected age data interpreted from measured concentrations of environmental tracers in groundwater from 1,399 National Water-Quality Assessment (NAWQA) Program groundwater sites across the United States. The tracers of interest were chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), and tritium/helium-3 (3H/3He). Tracer data compiled for this analysis primarily were from wells representing two types of NAWQA groundwater studies - Land-Use Studies (shallow wells, usually monitoring wells, in recharge areas under dominant land-use settings) and Major-Aquifer Studies (wells, usually domestic supply wells, in principal aquifers and representing the shallow, used resource). Reference wells (wells representing groundwater minimally impacted by anthropogenic activities) associated with Land-Use Studies also were included. Tracer samples were collected between 1992 and 2005, although two networks sampled from 2006 to 2007 were included because of network-specific needs. Tracer data from other NAWQA Program components (Flow System Studies, which are assessments of processes and trends along groundwater flow paths, and various topical studies) were not compiled herein. Tracer data from NAWQA Land-Use Studies and Major-Aquifer Studies that previously had been interpreted and published are compiled herein (as piston-flow ages), but have not been reinterpreted. Tracer data that previously had not been interpreted and published are evaluated using documented methods and compiled with aqueous concentrations, equivalent atmospheric concentrations (for CFCs and SF6), estimates of tracer-based piston-flow ages, and selected ancillary data, such as redox indicators, well construction, and major dissolved gases (N2, O2, Ar, CH4, and CO2). Tracer-based piston-flow ages documented in this report are simplistic representations of the tracer data. Tracer-based piston-flow ages are a convenient means of conceptualizing groundwater age. However, the piston

  7. EGS in sedimentary basins: sensitivity of early-flowback tracer signals to induced-fracture parameters

    Science.gov (United States)

    Karmakar, Shyamal; Ghergut, Julia; Sauter, Martin

    2015-04-01

    Artificial-fracture design, and fracture characterization during or following stimulation treatment is a central aspect of many EGS ('enhanced' or 'engineered' geothermal system) projects. During the creation or stimulation of an EGS, the injection of fluids, followed by flowback and production stages offers the opportunity for conducting various tracer tests in a single-well (SW) configuration, and given the typical operational and time limitations associated with such tests, along with the need to assess treatment success in real time, investigators mostly favour using short-time tracer-test data, rather than awaiting long-term 'tailings' of tracer signals. Late-time tracer signals from SW injection-flowback and production tests have mainly been used for the purpose of multiple-fracture inflow profiling in multi-layer reservoirs [1]. However, the potential of using SW short-term tracer signals for fracture characterization [2, 3] remained little explored as yet. Dealing with short-term flowback signals, we face a certain degree of parameter interplay, leading to ambiguity in fracture parameter inversion from the measured signal of a single tracer. This ambiguity can, to a certain extent, be overcome by - combining different sources of information (lithostratigraphy, and hydraulic monitoring) in order to constrain the variation range of hydrogeologic parameters (matrix and fracture permeability and porosity, fracture size), - using different types of tracers, such as conservative tracer pairs with contrasting diffusivity, or tracers pairs with contrasting sorptivity onto target surfaces. Fracture height is likely to be constrained by lithostratigraphy, while fracture length is supposed to be determinable from hydraulic monitoring (pressure recordings); the flowback rate can be assumed as a known (measurable) quantity during individual-fracture flowback. This leaves us with one or two unknown parameters to be determined from tracer signals: - the transport

  8. Analysis of tracer and thermal transients during reinjection

    Energy Technology Data Exchange (ETDEWEB)

    Kocabas, I.

    1989-10-01

    This work studied tracer and thermal transients during reinjection in geothermal reserviors and developed a new technique which combines the results from interwell tracer tests and thermal injection-backflow tests to estimate the thermal breakthrough times. Tracer tests are essential to determine the degree of connectivity between the injection wells and the producing wells. To analyze the tracer return profiles quantitatively, we employed three mathematical models namely, the convection-dispersion (CD) model, matrix diffusion (MD) model, and the Avodnin (AD) model, which were developed to study tracer and heat transport in a single vertical fracture. We considered three types of tracer tests namely, interwell tracer tests without recirculation, interwell tracer tests with recirculation, and injection-backflow tracer tests. To estimate the model parameters, we used a nonlinear regression program to match tracer return profiles to the solutions.

  9. Evaluation of leakage from fume hoods using tracer gas, tracer nanoparticles and nanopowder handling test methodologies.

    Science.gov (United States)

    Dunn, Kevin H; Tsai, Candace Su-Jung; Woskie, Susan R; Bennett, James S; Garcia, Alberto; Ellenbecker, Michael J

    2014-01-01

    The most commonly reported control used to minimize workplace exposures to nanomaterials is the chemical fume hood. Studies have shown, however, that significant releases of nanoparticles can occur when materials are handled inside fume hoods. This study evaluated the performance of a new commercially available nano fume hood using three different test protocols. Tracer gas, tracer nanoparticle, and nanopowder handling protocols were used to evaluate the hood. A static test procedure using tracer gas (sulfur hexafluoride) and nanoparticles as well as an active test using an operator handling nanoalumina were conducted. A commercially available particle generator was used to produce sodium chloride tracer nanoparticles. Containment effectiveness was evaluated by sampling both in the breathing zone (BZ) of a mannequin and operator as well as across the hood opening. These containment tests were conducted across a range of hood face velocities (60, 80, and 100 ft/min) and with the room ventilation system turned off and on. For the tracer gas and tracer nanoparticle tests, leakage was much more prominent on the left side of the hood (closest to the room supply air diffuser) although some leakage was noted on the right side and in the BZ sample locations. During the tracer gas and tracer nanoparticle tests, leakage was primarily noted when the room air conditioner was on for both the low and medium hood exhaust airflows. When the room air conditioner was turned off, the static tracer gas tests showed good containment across most test conditions. The tracer gas and nanoparticle test results were well correlated showing hood leakage under the same conditions and at the same sample locations. The impact of a room air conditioner was demonstrated with containment being adversely impacted during the use of room air ventilation. The tracer nanoparticle approach is a simple method requiring minimal setup and instrumentation. However, the method requires the reduction in

  10. Journal: A Review of Some Tracer-Test Design Equations for Tracer-Mass Estimation and Sample Collection Frequency

    Science.gov (United States)

    Determination of necessary tracer mass, initial sample-collection time, and subsequent sample-collection frequency are the three most difficult aspects to estimate for a proposed tracer test prior to conducting the tracer test. To facilitate tracer-mass estimation, 33 mass-estima...

  11. Journal: A Review of Some Tracer-Test Design Equations for Tracer-Mass Estimation and Sample Collection Frequency

    Science.gov (United States)

    Determination of necessary tracer mass, initial sample-collection time, and subsequent sample-collection frequency are the three most difficult aspects to estimate for a proposed tracer test prior to conducting the tracer test. To facilitate tracer-mass estimation, 33 mass-estima...

  12. Detection of perfluorinated taggants in electric blasting caps by electron capture monitors

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, R N; Goodrich, R W; Cote, E A

    1978-01-01

    Three types of monitors or detecting instruments for determining the presence of perfluorinated taggants have been developed and validated in field studies. Each of the three versions--a portable continuous real-time monitor, a portable concentrating chromatograph, and a fixed station high sensitivity chromatograph -- have been utilized for detecting these types of compounds in atmospheric tracer studies. The portable continuous monitor, which has a detection capability of two parts of taggant in one trillion parts of air (2 pp 10/sup 12/), has been used in three field tracer studies in the past 18 months, operating on-board aircraft. In a scenario such as continuous on-line screening of checked and hand-carried luggage at airport environments, the sensitivity and response time are more than adequate. Confirmation of the method applied to conveyor belt suitcase screening has been demonstrated. A small concentrating field instrument was developed and field tested more than a year ago. Five minute repetitive sampling rates are estimated to ultimately provide limits of detection for the taggant compounds at about 5 pp 10/sup 16/ and could be extended as much as another 50-fold lower. Applications potentially include detecting vapor tagged explosives in meeting rooms, corridors and passageways, and on-board aircraft.

  13. Vapor pressures and enthalpies of vaporization of azides

    Energy Technology Data Exchange (ETDEWEB)

    Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Emel' yanenko, Vladimir N. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Algarra, Manuel [Centro de Geologia do Porto, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Manuel Lopez-Romero, J. [Department of Organic Chemistry, University of Malaga. Campus de Teatinos s/n, 29071 Malaga (Spain); Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G. [Centro de Investigacao em Quimica (CIQ-UP), Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2011-11-15

    Highlights: > We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. > We examined consistency of new and available in the literature data. > Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization {Delta}{sub l}{sup g}H{sub m} of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  14. Tracer-based prediction of thermal reservoir lifetime: scope, limitations, and the role of thermosensitive tracers

    Science.gov (United States)

    Ghergut, I.; Behrens, H.; Karmakar, S.; Licha, T.; Nottebohm, M.; Sauter, M.

    2012-04-01

    Thermal-lifetime prediction is a traditional endeavour of inter-well tracer tests conducted in geothermal reservoirs. Early tracer test signals (detectable within the first few years of operation) are expected to correlate with late-time production temperature evolutions ('thermal breakthrough', supposed to not occur before some decades of operation) of a geothermal reservoir. Whenever a geothermal reservoir can be described as a single-fracture system, its thermal lifetime will, ideally, be determined by two parameters (say, fracture aperture and porosity), whose inversion from conservative-tracer test signals is straightforward and non-ambiguous (provided that the tracer tests, and their interpretation, are performed in accordance to the rules of the art). However, as soon as only 'few more' fractures are considered, this clear-cut correlation is broken. A given geothermal reservoir can simultaneously feature a single-fracture behaviour, in terms of heat transport, and a multiple-fracture behaviour, in terms of solute tracer transport (or vice-versa), whose effective values of fracture apertures, spacings, and porosities are essentially uncorrelated between heat and solute tracers. Solute transport parameters derived from conservative-tracer tests will no longer characterize the heat transport processes (and thus temperature evolutions) taking place in the same reservoir. Parameters determining its thermal lifetime will remain 'invisible' to conservative tracers in inter-well tests. We demonstrate this issue at the example of a five-fracture system, representing a deep-geothermal reservoir, with well-doublet placement inducing fluid flow 'obliquely' to the fractures. Thermal breakthrough in this system is found to strongly depend on fracture apertures, whereas conservative-solute tracer signals from inter-well tests in the same system do not show a clear-cut correlation with fracture apertures. Only by using thermosensitive substances as tracers, a reliable

  15. Tungsten chemical vapor deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Kiichi; Takeda, Nobuo.

    1993-07-13

    A tungsten chemical vapor deposition method is described, comprising: a first step of selectively growing a first thin tungsten film of a predetermined thickness in a desired region on the surface of a silicon substrate by reduction of a WF[sub 6] gas introduced into an atmosphere of a predetermined temperature containing said silicon substrate; and a second step of selectively growing a second tungsten film of a predetermined thickness on said first thin tungsten film by reduction of said WF[sub 6] with a silane gas further introduced into said atmosphere, wherein the surface state of said substrate is monitored by a pyrometer and the switching from said first step to said second step is performed when the emissivity of infrared light from the substrate surfaces reaches a predetermined value.

  16. Optimal sampler siting for atmospheric tracer experiments taking into account uncertainties in the wind field

    Science.gov (United States)

    Pitovranov, Sergei E.; Federov, Valery V.; Edwards, Leslie L.

    The problem of sampling sites for atmospheric tracer experiments were considered in Federov and Pitorvranov (working paper WP-85-65, International Institute for Applied Systems Analysis, Laxenburg, Austria, 1988). There it was assumed that the wind direction during an experimental tracer release could be accurately predetermined and would remain constant for the duration of the experiment. In general, this assumption of a constant wind field is not met. In this work we develop an approach which overcomes this deficiency. The monitoring network design problem is considered for cases which include prior uncertain wind fields during a designed experiment.

  17. Testing and comparison of four ionic tracers to measure stream flow loss by multiple tracer injection

    Science.gov (United States)

    Zellweger, G.W.

    1994-01-01

    An injectate containing lithium, sodium, chloride and bromide was added continuously at five sites along a 507 m study reach of St Kevin Gulch, Lake County, Colorado to determine which sections of the stream were losing water to the stream bed and to ascertain how well the four tracers performed. The acidity of the stream (pH 3.6) made it possible for lithium and sodium, which are normally absorbed by ion exchange with stream bed sediment, to be used as conservative tracers. Net flow losses as low as 0.81 s-1, or 8% of flow, were calculated between measuring sites. By comparing the results of simultaneous injection it was determined whether subsections of the study reach were influent or effluent. Evaluation of tracer concentrations along 116 m of stream indicated that all four tracers behaved conservatively. Discharges measured by Parshall flumes were 4-18% greater than discharges measured by tracer dilution. -from Author

  18. TRACER - TRACING AND CONTROL OF ENGINEERING REQUIREMENTS

    Science.gov (United States)

    Turner, P. R.

    1994-01-01

    TRACER (Tracing and Control of Engineering Requirements) is a database/word processing system created to document and maintain the order of both requirements and descriptive material associated with an engineering project. A set of hierarchical documents are normally generated for a project whereby the requirements of the higher level documents levy requirements on the same level or lower level documents. Traditionally, the requirements are handled almost entirely by manual paper methods. The problem with a typical paper system, however, is that requirements written and changed continuously in different areas lead to misunderstandings and noncompliance. The purpose of TRACER is to automate the capture, tracing, reviewing, and managing of requirements for an engineering project. The engineering project still requires communications, negotiations, interactions, and iterations among people and organizations, but TRACER promotes succinct and precise identification and treatment of real requirements separate from the descriptive prose in a document. TRACER permits the documentation of an engineering project's requirements and progress in a logical, controllable, traceable manner. TRACER's attributes include the presentation of current requirements and status from any linked computer terminal and the ability to differentiate headers and descriptive material from the requirements. Related requirements can be linked and traced. The program also enables portions of documents to be printed, individual approval and release of requirements, and the tracing of requirements down into the equipment specification. Requirement "links" can be made "pending" and invisible to others until the pending link is made "binding". Individuals affected by linked requirements can be notified of significant changes with acknowledgement of the changes required. An unlimited number of documents can be created for a project and an ASCII import feature permits existing documents to be incorporated

  19. TRACER - TRACING AND CONTROL OF ENGINEERING REQUIREMENTS

    Science.gov (United States)

    Turner, P. R.

    1994-01-01

    TRACER (Tracing and Control of Engineering Requirements) is a database/word processing system created to document and maintain the order of both requirements and descriptive material associated with an engineering project. A set of hierarchical documents are normally generated for a project whereby the requirements of the higher level documents levy requirements on the same level or lower level documents. Traditionally, the requirements are handled almost entirely by manual paper methods. The problem with a typical paper system, however, is that requirements written and changed continuously in different areas lead to misunderstandings and noncompliance. The purpose of TRACER is to automate the capture, tracing, reviewing, and managing of requirements for an engineering project. The engineering project still requires communications, negotiations, interactions, and iterations among people and organizations, but TRACER promotes succinct and precise identification and treatment of real requirements separate from the descriptive prose in a document. TRACER permits the documentation of an engineering project's requirements and progress in a logical, controllable, traceable manner. TRACER's attributes include the presentation of current requirements and status from any linked computer terminal and the ability to differentiate headers and descriptive material from the requirements. Related requirements can be linked and traced. The program also enables portions of documents to be printed, individual approval and release of requirements, and the tracing of requirements down into the equipment specification. Requirement "links" can be made "pending" and invisible to others until the pending link is made "binding". Individuals affected by linked requirements can be notified of significant changes with acknowledgement of the changes required. An unlimited number of documents can be created for a project and an ASCII import feature permits existing documents to be incorporated

  20. Glowing clay: Real time tracing using a suite of novel clay based fluorescent tracers

    Science.gov (United States)

    Hardy, Robert; Quinton, John; Pates, Jackie; Coogan, Mike

    2015-04-01

    Clay is one of the most mobile fractions of soil due to its small particle size. It is also known to sorb many chemicals, such as nutrients (notably phosphorus), agrochemicals and heavy metals. The movement of clay is therefore linked with the transport and fate of these substances. A novel fluorescent clay tracing suite has been produced, together with an imaging technique. This suite consists of qualitative clay tracers, using rhodamine based fluorophores, and quantitative clay tracers, using metal based fluorophores. Efforts have also been made to allow integration of commercially available tracers, which are silt and sand sized. The clay tracers exploit the high affinity that montmorillonite has for Rhodamine B and Ru(bpy)3. This allows for an extremely thin layer of the fluorophore to be sorbed onto the clay's surface, in much that same way as materials in the natural environment will bind to clay. The tracer that is produced retains key chemical and physical properties of clay, such as size, shape and density. The retention of these micro-properties results in the retention of macro-properties, such as tendency to aggregate and cracking on drying. Imaging techniques have been developed to analyse these tracers. The imaging system uses diffused laser light to excite the tracer and a modified DSLR camera to image the soil surface. The images have been compiled into a time lapse video showing the movement of clay over the course of a rainfall event. This is the first time that the quantitative movement of clay has been recorded over a soil surface in real time. 4D data can be extracted from the images allowing the spatial location and intensity of tracer to be monitored over time, with mm precision and on the timescale of seconds. As the system can also work with a commercial tracer it is possible to investigate the movement of particles of almost any size and over a range of scales from soil box to hillside. This allows users to access this technique without

  1. Nitrous oxide as a tracer gas in the ASHRAE 110-1995 Standard.

    Science.gov (United States)

    Burke, Martin; Wong, Larry; Gonzales, Ben A; Knutson, Gerhard

    2014-01-01

    ANSI/ASHRAE Standard 110 provides a quantitative method for testing the performance of laboratory fume hoods. Through release of a known quantity (4.0 Lpm) of a tracer gas, and subsequent monitoring of the tracer gas concentration in the "breathing zone" of a mannequin positioned in front of the hood, this method allows for evaluation of laboratory hood performance. Standard 110 specifies sulfur hexafluoride (SF6) as the tracer gas; however, suitable alternatives are allowed. Through three series of performance tests, this analysis serves to investigate the use of nitrous oxide (N2O) as an alternate tracer gas for hood performance testing. Single gas tests were performed according to ASHRAE Standard 110-1995 with each tracer gas individually. These tests showed identical results using an acceptance criterion of AU 0.1 with the sash half open, nominal 18 inches (0.46m) high, and the face velocity at a nominal 60 fpm (0.3 m/s). Most data collected in these single gas tests, for both tracer gases, were below the minimum detection limit, thus two dual gas tests were developed for simultaneous sampling of both tracer gases. Dual gas dual ejector tests were performed with both tracer gases released simultaneously through two ejectors, and the concentration measured with two detectors using a common sampling probe. Dual gas single ejector tests were performed with both tracer gases released though a single ejector, and the concentration measured in the same manner as the dual gas dual ejector tests. The dual gas dual ejector tests showed excellent correlation, with R typically greater than 0.9. Variance was observed in the resulting regression line for each hood, likely due to non-symmetry between the two challenges caused by variables beyond the control of the investigators. Dual gas single ejector tests resulted in exceptional correlation, with R>0.99 typically for the consolidated data, with a slope of 1.0. These data indicate equivalent results for ASHRAE 110

  2. Heat tracer test in an alluvial aquifer: Field experiment and inverse modelling

    Science.gov (United States)

    Klepikova, Maria; Wildemeersch, Samuel; Hermans, Thomas; Jamin, Pierre; Orban, Philippe; Nguyen, Frédéric; Brouyère, Serge; Dassargues, Alain

    2016-09-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in an injection well and monitoring the evolution of groundwater temperature and tracer concentration in the pumping well and in measurement intervals. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells closely spaced along three transects were used. Temperature breakthrough curves in observation wells are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. The observed complex behavior of the heat plume is explained by the groundwater flow gradient on the site and heterogeneities in the hydraulic conductivity field. Moreover, due to high injection temperatures during the field experiment a temperature-induced fluid density effect on heat transport occurred. By using a flow and heat transport numerical model with variable density coupled with a pilot point approach for inversion of the hydraulic conductivity field, the main preferential flow paths were delineated. The successful application of a field heat tracer test at this site suggests that heat tracer tests is a promising approach to image hydraulic conductivity field. This methodology could be applied in aquifer thermal energy storage (ATES) projects for assessing future efficiency that is strongly linked to the hydraulic conductivity variability in the considered aquifer.

  3. Variations in stable hydrogen and oxygen isotopes in atmospheric water vapor in the marine boundary layer across a wide latitude range.

    Science.gov (United States)

    Liu, Jingfeng; Xiao, Cunde; Ding, Minghu; Ren, Jiawen

    2014-11-01

    The newly-developed cavity ring-down laser absorption spectroscopy analyzer with special calibration protocols has enabled the direct measurement of atmospheric vapor isotopes at high spatial and temporal resolution. This paper presents real-time hydrogen and oxygen stable isotope data for atmospheric water vapor above the sea surface, over a wide range of latitudes spanning from 38°N to 69°S. Our results showed relatively higher values of δ(18)O and δ(2)H in the subtropical regions than those in the tropical and high latitude regions, and also a notable decreasing trend in the Antarctic coastal region. By combining the hydrogen and oxygen isotope data with meteoric water line and backward trajectory model analysis, we explored the kinetic fractionation caused by subsiding air masses and related saturated vapor pressure in the subtropics, and the evaporation-driven kinetic fractionation in the Antarctic region. Simultaneous observations of meteorological and marine variables were used to interpret the isotopic composition characteristics and influential factors, indicating that d-excess is negatively correlated with humidity across a wide range of latitudes and weather conditions worldwide. Coincident with previous studies, d-excess is also positively correlated with sea surface temperature and air temperature (Tair), with greater sensitivity to Tair. Thus, atmospheric vapor isotopes measured with high accuracy and good spatial-temporal resolution could act as informative tracers for exploring the water cycle at different regional scales. Such monitoring efforts should be undertaken over a longer time period and in different regions of the world.

  4. Enhanced Oil Recovery: Aqueous Flow Tracer Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Rovani; John Schabron

    2009-02-01

    A low detection limit analytical method was developed to measure a suite of benzoic acid and fluorinated benzoic acid compounds intended for use as tracers for enhanced oil recovery operations. Although the new high performance liquid chromatography separation successfully measured the tracers in an aqueous matrix at low part per billion levels, the low detection limits could not be achieved in oil field water due to interference problems with the hydrocarbon-saturated water using the system's UV detector. Commercial instrument vendors were contacted in an effort to determine if mass spectrometry could be used as an alternate detection technique. The results of their work demonstrate that low part per billion analysis of the tracer compounds in oil field water could be achieved using ultra performance liquid chromatography mass spectrometry.

  5. Passive Vaporizing Heat Sink

    Science.gov (United States)

    Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.

    2011-01-01

    A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

  6. An unsteady state tracer method for characterizing fractures in bedrock wells.

    Science.gov (United States)

    Libby, Jill L; Robbins, Gary A

    2014-01-01

    Evaluating contaminants impacting wells in fractured crystalline rock requires knowledge of the individual fractures contributing water. This typically involves using a sequence of tools including downhole geophysics, flow meters, and straddle packers. In conjunction with each other these methods are expensive, time consuming, and can be logistically difficult to implement. This study demonstrates an unsteady state tracer method as a cost-effective alternative for gathering fracture information in wells. The method entails introducing tracer dye throughout the well, inducing fracture flow into the well by conducting a slug test and then profiling the tracer concentration in the well to locate water contributing fractures where the dye has been diluted. By monitoring the development of the dilution zones within the wellbore with time, the transmissivity and the hydraulic head of the water contributing fractures can be determined. Ambient flow conditions and the contaminant concentration within the fractures can also be determined from the tracer dilution. This method was tested on a large physical model well and a bedrock well. The model well was used to test the theory underlying the method and to refine method logistics. The approach located the fracture and generated transmissivity values that were in excellent agreement with those calculated by slug testing. For the bedrock well tested, two major active fractures were located. Fracture location and ambient well conditions matched results from conventional methods. Estimates of transmissivity values by the tracer method were within an order of magnitude of those calculated using heat-pulse flow meter data.

  7. Transformationally decoupling clustering and tracer bias

    CERN Document Server

    Neyrinck, Mark C

    2014-01-01

    Gaussianizing transformations are used statistically in many non-cosmological fields, but in cosmology, we are only starting to apply them. Here I explain a strategy of analyzing the 1-point function (PDF) of a spatial field, together with the 'essential' clustering statistics of the Gaussianized field, which are invariant to a local transformation. In cosmology, if the tracer sampling is sufficient, this achieves two important goals. First, it can greatly multiply the Fisher information, which is negligible on nonlinear scales in the usual $\\delta$ statistics. Second, it decouples clustering statistics from a local bias description for tracers such as galaxies.

  8. Geologic flow characterization using tracer techniques

    Energy Technology Data Exchange (ETDEWEB)

    Klett, R. D.; Tyner, C. E.; Hertel, Jr., E. S.

    1981-04-01

    A new tracer flow-test system has been developed for in situ characterization of geologic formations. This report describes two sets of test equipment: one portable and one for testing in deep formations. Equations are derived for in situ detector calibration, raw data reduction, and flow logging. Data analysis techniques are presented for computing porosity and permeability in unconfined isotropic media, and porosity, permeability and fracture characteristics in media with confined or unconfined two-dimensional flow. The effects of tracer pulse spreading due to divergence, dispersion, and porous formations are also included.

  9. Identification and quantification of the antimicrobial components of a citrus essential oil vapor.

    Science.gov (United States)

    Phillips, Carol A; Gkatzionis, Konstantinos; Laird, Katie; Score, Jodie; Kant, Avinash; Fielder, Mark D

    2012-01-01

    The anti-bacterial components of a citrus essential oil vapor were identified as linalool, citral and beta-pinene using a bioautography method and quantified by GC-MS. Essential oil vapor release, monitored in real-time with Atmospheric Pressure Chemical Ionization - MS (APCI-MS), showed differences in the vapor release profile oflimonene, beta-pinene and linalool over 24 hours, while Solid Phase Micro-extraction (SPME) GC-MS demonstrated changes in composition of the vapor at 35 degrees C. Fourteen isolates were tested in vitro for their susceptibility to the EO vapor and to linalool, citral and beta-pinene vapors, both separately and in a mixture containing the three components in the amounts at which they occur in the EO vapor. All eleven Gram-positive strains tested were susceptible to the EO vapor, linalool, citral and beta-pinene vapors separately and the mixture with zones of inhibition of 4.34 cm, 5.32 cm, 5.58 cm, 4.86 cm and 4.68 cm, respectively. Of the three Gram-negative strains tested, Pseudomonas aeruginosa 10145 was resistant to all the vapors. When bacteria inoculated onto stainless steel surfaces were exposed to either the EO vapor or a linalool/citral/beta-pinene vapor mixture there was no significant difference in reduction for the Gram-positive isolates, while the Gram-negative isolates were resistant to both EO vapor and the linalool/citral/beta-pinene mixture.

  10. A review of methods for modelling environmental tracers in groundwater: Advantages of tracer concentration simulation

    Science.gov (United States)

    Turnadge, Chris; Smerdon, Brian D.

    2014-11-01

    Mathematical models of varying complexity have been developed since the 1960s to interpret environmental tracer concentrations in groundwater flow systems. This review examines published studies of model-based environmental tracer interpretation, the progress of different modelling approaches, and also considers the value of modelling tracer concentrations directly rather than estimations of groundwater age. Based on citation metrics generated using the Web of Science and Google Scholar reference databases, the most highly utilised interpretation approaches are lumped parameter models (421 citations), followed closely by direct age models (220 citations). A third approach is the use of mixing cell models (99 citations). Although lumped parameter models are conceptually simple and require limited data, they are unsuitable for characterising the internal dynamics of a hydrogeological system and/or under conditions where large scale anthropogenic stresses occur within a groundwater basin. Groundwater age modelling, and in particular, the simulation of environmental tracer transport that explicitly accounts for the accumulation and decay of tracer mass, has proven to be highly beneficial in constraining numerical models. Recent improvements in computing power have made numerical simulation of tracer transport feasible. We argue that, unlike directly simulated ages, the results of tracer mass transport simulation can be compared directly to observations, without needing to correct for apparent age bias or other confounding factors.

  11. 40 CFR 63.649 - Alternative means of emission limitation: Connectors in gas/vapor service and light liquid service.

    Science.gov (United States)

    2010-07-01

    ... limitation: Connectors in gas/vapor service and light liquid service. 63.649 Section 63.649 Protection of...: Connectors in gas/vapor service and light liquid service. (a) If an owner or operator elects to monitor... gas/vapor service and for connectors in light liquid service. The data for the two groups...

  12. Tracer SWIW tests in propped and un-propped fractures: parameter sensitivity issues, revisited

    Science.gov (United States)

    Ghergut, Julia; Behrens, Horst; Sauter, Martin

    2017-04-01

    -scale diffusion; (iii) attempt to determine both advective and non-advective transport parameters from one and the same conservative-tracer signal (relying on 'third-party' knowledge), or from twin signals of a so-called 'dual' tracer pair, e. g.: using tracers with contrasting reactivity and partitioning behavior to determine residual saturation in depleted oilfields (Tomich et al. 1973), or to determine advective parameters (Ghergut et al. 2014); using early-time signals of conservative and sorptive tracers for propped-fracture characterization (Karmakar et al. 2015); using mid-time signals of conservative tracers for a reservoir-borne inflow profiling in multi-frac systems (Ghergut et al. 2016), etc. The poster describes new uses of type-(iii) techniques for the specific purposes of shale-gas reservoir characterization, productivity monitoring, diagnostics and engineering of 're-frac' treatments, based on parameter sensitivity findings from German BMWi research project "TRENDS" (Federal Ministry for Economic Affairs and Energy, FKZ 0325515) and from the EU-H2020 project "FracRisk" (grant no. 640979).

  13. Accuracy of travel time distribution (TTD) models as affected by TTD complexity, observation errors, and model and tracer selection

    Science.gov (United States)

    Green, Christopher T.; Zhang, Yong; Jurgens, Bryant C.; Starn, J. Jeffrey; Landon, Matthew K.

    2014-01-01

    Analytical models of the travel time distribution (TTD) from a source area to a sample location are often used to estimate groundwater ages and solute concentration trends. The accuracies of these models are not well known for geologically complex aquifers. In this study, synthetic datasets were used to quantify the accuracy of four analytical TTD models as affected by TTD complexity, observation errors, model selection, and tracer selection. Synthetic TTDs and tracer data were generated from existing numerical models with complex hydrofacies distributions for one public-supply well and 14 monitoring wells in the Central Valley, California. Analytical TTD models were calibrated to synthetic tracer data, and prediction errors were determined for estimates of TTDs and conservative tracer (NO3−) concentrations. Analytical models included a new, scale-dependent dispersivity model (SDM) for two-dimensional transport from the watertable to a well, and three other established analytical models. The relative influence of the error sources (TTD complexity, observation error, model selection, and tracer selection) depended on the type of prediction. Geological complexity gave rise to complex TTDs in monitoring wells that strongly affected errors of the estimated TTDs. However, prediction errors for NO3− and median age depended more on tracer concentration errors. The SDM tended to give the most accurate estimates of the vertical velocity and other predictions, although TTD model selection had minor effects overall. Adding tracers improved predictions if the new tracers had different input histories. Studies using TTD models should focus on the factors that most strongly affect the desired predictions.

  14. Blood tracer kinetics in the arterial tree.

    Directory of Open Access Journals (Sweden)

    Elias Kellner

    Full Text Available Evaluation of blood supply of different organs relies on labeling blood with a suitable tracer. The tracer kinetics is linear: Tracer concentration at an observation site is a linear response to an input somewhere upstream the arterial flow. The corresponding impulse response functions are currently treated empirically without incorporating the relation to the vascular morphology of an organ. In this work we address this relation for the first time. We demonstrate that the form of the response function in the entire arterial tree is reduced to that of individual vessel segments under approximation of good blood mixing at vessel bifurcations. The resulting expression simplifies significantly when the geometric scaling of the vascular tree is taken into account. This suggests a new way to access the vascular morphology in vivo using experimentally determined response functions. However, it is an ill-posed inverse problem as demonstrated by an example using measured arterial spin labeling in large brain arteries. We further analyze transport in individual vessel segments and demonstrate that experimentally accessible tracer concentration in vessel segments depends on the measurement principle. Explicit expressions for the response functions are obtained for the major middle part of the arterial tree in which the blood flow in individual vessel segments can be treated as laminar. When applied to the analysis of regional cerebral blood flow measurements for which the necessary arterial input is evaluated in the carotid arteries, present theory predicts about 20% underestimation, which is in agreement with recent experimental data.

  15. Blood tracer kinetics in the arterial tree.

    Science.gov (United States)

    Kellner, Elias; Gall, Peter; Günther, Matthias; Reisert, Marco; Mader, Irina; Fleysher, Roman; Kiselev, Valerij G

    2014-01-01

    Evaluation of blood supply of different organs relies on labeling blood with a suitable tracer. The tracer kinetics is linear: Tracer concentration at an observation site is a linear response to an input somewhere upstream the arterial flow. The corresponding impulse response functions are currently treated empirically without incorporating the relation to the vascular morphology of an organ. In this work we address this relation for the first time. We demonstrate that the form of the response function in the entire arterial tree is reduced to that of individual vessel segments under approximation of good blood mixing at vessel bifurcations. The resulting expression simplifies significantly when the geometric scaling of the vascular tree is taken into account. This suggests a new way to access the vascular morphology in vivo using experimentally determined response functions. However, it is an ill-posed inverse problem as demonstrated by an example using measured arterial spin labeling in large brain arteries. We further analyze transport in individual vessel segments and demonstrate that experimentally accessible tracer concentration in vessel segments depends on the measurement principle. Explicit expressions for the response functions are obtained for the major middle part of the arterial tree in which the blood flow in individual vessel segments can be treated as laminar. When applied to the analysis of regional cerebral blood flow measurements for which the necessary arterial input is evaluated in the carotid arteries, present theory predicts about 20% underestimation, which is in agreement with recent experimental data.

  16. Fractal tracer distributions in turbulent field theories

    DEFF Research Database (Denmark)

    Hansen, J. Lundbek; Bohr, Tomas

    1998-01-01

    We study the motion of passive tracers in a two-dimensional turbulent velocity field generated by the Kuramoto-Sivashinsky equation. By varying the direction of the velocity-vector with respect to the field-gradient we can continuously vary the two Lyapunov exponents for the particle motion and t...

  17. Suitability of tracers; Eignung von Tracern

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, D. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany). Inst. fuer Hydrologie

    1999-02-01

    Hydrological tracer techniques are a means of making statements on the direction and speed of underground water. One of the simpler tasks is to find out whether there is hydrological communication between two given points. This requires a determination of the direction of flow, which places less exacting demands on the properties of the tracer than does the task of determining the flow velocity of underground water. Tracer methods can serve to infer from flow velocity the distance (flow) velocity, which is defined as the ratio between the distance between two points located in flow direction and the actual time it takes water to flow from one to the other. [Deutsch] Mit Hilfe der hydrologischen Markierungstechniken koennen Aussagen ueber die Richtung und die Geschwindigkeit von Bewegungen des unterirdischen Wassers gemacht werden. Der einfachere Fall liegt vor, wenn festgestellt werden soll, ob zwischen zwei Punkten eine hydrologische Verbindung besteht. Bei dieser Fliessrichtungsbestimmung sind die Forderungen an die Eigenschaften der einzusetzenden Tracer geringer als bei der Bestimmung der Geschwindigkeit des unterirdischen Wassers. Von den Geschwindigkeiten des unterirdischen Wassers ist die Abstands-(Fliess)geschwindigkeit, die definiert ist durch das Verhaeltnis aus dem Abstand und der wahren Fliesszeit zwischen zwei in Bewegungsrichtung gelegenen Punkten, durch Tracermethoden zu bestimmen. (orig.)

  18. Using neural networks to describe tracer correlations

    Directory of Open Access Journals (Sweden)

    D. J. Lary

    2004-01-01

    Full Text Available Neural networks are ideally suited to describe the spatial and temporal dependence of tracer-tracer correlations. The neural network performs well even in regions where the correlations are less compact and normally a family of correlation curves would be required. For example, the CH4-N2O correlation can be well described using a neural network trained with the latitude, pressure, time of year, and methane volume mixing ratio (v.m.r.. In this study a neural network using Quickprop learning and one hidden layer with eight nodes was able to reproduce the CH4-N2O correlation with a correlation coefficient between simulated and training values of 0.9995. Such an accurate representation of tracer-tracer correlations allows more use to be made of long-term datasets to constrain chemical models. Such as the dataset from the Halogen Occultation Experiment (HALOE which has continuously observed CH4  (but not N2O from 1991 till the present. The neural network Fortran code used is available for download.

  19. Travel-time-based thermal tracer tomography

    Science.gov (United States)

    Somogyvári, Márk; Bayer, Peter; Brauchler, Ralf

    2016-05-01

    Active thermal tracer testing is a technique to get information about the flow and transport properties of an aquifer. In this paper we propose an innovative methodology using active thermal tracers in a tomographic setup to reconstruct cross-well hydraulic conductivity profiles. This is facilitated by assuming that the propagation of the injected thermal tracer is mainly controlled by advection. To reduce the effects of density and viscosity changes and thermal diffusion, early-time diagnostics are used and specific travel times of the tracer breakthrough curves are extracted. These travel times are inverted with an eikonal solver using the staggered grid method to reduce constraints from the pre-defined grid geometry and to improve the resolution. Finally, non-reliable pixels are removed from the derived hydraulic conductivity tomograms. The method is applied to successfully reconstruct cross-well profiles as well as a 3-D block of a high-resolution fluvio-aeolian aquifer analog data set. Sensitivity analysis reveals a negligible role of the injection temperature, but more attention has to be drawn to other technical parameters such as the injection rate. This is investigated in more detail through model-based testing using diverse hydraulic and thermal conditions in order to delineate the feasible range of applications for the new tomographic approach.

  20. Nanoparticle tracers in calcium carbonate porous media

    KAUST Repository

    Li, Yan Vivian

    2014-07-15

    Tracers are perhaps the most direct way of diagnosing subsurface fluid flow pathways for ground water decontamination and for natural gas and oil production. Nanoparticle tracers could be particularly effective because they do not diffuse away from the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles are not retained in the porous media as the result of aggregation or sticking to mineral surfaces. By screening eight nanoparticles (3-100 nm in diameter) for retention when passed through calcium carbonate packed laboratory columns in artificial oil field brine solutions of variable ionic strength we show that the nanoparticles with the least retention are 3 nm in diameter, nearly uncharged, and decorated with highly hydrophilic polymeric ligands. The details of these column experiments and the tri-modal distribution of zeta potential of the calcite sand particles in the brine used in our tests suggests that parts of the calcite surface have positive zeta potential and the retention of negatively charged nanoparticles occurs at these sites. Only neutral nanoparticles are immune to at least some retention. © 2014 Springer Science+Business Media.

  1. B and Li isotopes as intrinsic tracers for injection tests in aquifer storage and recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Kloppmann, Wolfram, E-mail: w.kloppmann@brgm.fr [BRGM, French Geological Survey, 3 Av. Claude Guillemin B.P. 6009, F-45000 Orleans (France); Chikurel, Haim [Mekorot National Water Company, Tel Aviv (Israel); Picot, Geraldine [BRGM, French Geological Survey, 3 Av. Claude Guillemin B.P. 6009, F-45000 Orleans (France); Guttman, Joseph [Mekorot National Water Company, Tel Aviv (Israel); Pettenati, Marie [BRGM, French Geological Survey, 3 Av. Claude Guillemin B.P. 6009, F-45000 Orleans (France); Aharoni, Avi [Mekorot National Water Company, Tel Aviv (Israel); Guerrot, Catherine; Millot, Romain; Gaus, Irina [BRGM, French Geological Survey, 3 Av. Claude Guillemin B.P. 6009, F-45000 Orleans (France); Wintgens, Thomas [Rheinisch Westfaelische Technische Hochschule, RWTH, Aachen (Germany)

    2009-07-15

    Boron and Li isotopes have been tested as environmental tracers of treated sewage injected into a sandy aquifer (Shafdan reclamation project, Israel). During a 38 days injection test in a newly dug injection well, a conservative artificial tracer (Br{sup -}) was monitored together with {delta}{sup 11}B and {delta}{sup 7}Li in the injectate, in the unsaturated soil zone (porous cup) and an observation well in the aquifer. In spite of B and Li concentrations in the injectate close to background values, significant shifts of the isotope signatures could be observed over the duration of the injection test. Boron isotope ratios show a breakthrough curve delayed with respect to Br{sup -} breakthrough due to some reversible sorption on the aquifer material. No isotope fractionation was observed in the unsaturated or the saturated zone so that B isotopes can be considered as conservative in the investigated part of the aquifer system. Lithium isotopes are strongly fractionated, probably due to sorption processes. Lithium concentrations point to a Li sink in the system, {delta}{sup 7}Li values vary strongly with a tendency of {sup 7}Li depletion in the liquid phase over the duration of the experiment. This is opposite to the expected preferential sorption of {sup 6}Li onto clay minerals. Boron isotopes reveals a valuable tracer of artificial recharge of freshwaters derived from treated sewage, both for short term tracer tests and for long-term monitoring of artificial recharge, even if in aquifers with higher clay contents, sorption-linked isotope fractionation cannot be excluded. More data are needed on Li isotope fractionation in natural groundwater systems to assess the potential of this tracer as monitoring tool.

  2. Tracer injection techniques in flowing surface water

    Science.gov (United States)

    Wörman, A.

    2009-04-01

    Residence time distributions for flowing water and reactive matter are commonly used integrated properties of the transport process for determining technical issues of water resource management and in eco-hydrological science. Two general issues for tracer techniques are that the concentration-vs-time relation following a tracer injection (the breakthrough curve) gives unique transport information in different parts of the curve and separation of hydromechanical and reactive mechanisms often require simultaneous tracer injections. This presentation discusses evaluation methods for simultaneous tracer injections based on examples of tracer experiments in small rivers, streams and wetlands. Tritiated water is used as a practically inert substance to reflect the actual hydrodynamics, but other involved tracers are Cr(III)-51, P-32 and N-15. Hydromechanical, in-stream dispersion is reflected as a symmetrical spreading of the spatial concentration distribution. This requires that the transport distance over water depth is larger than about five times the flow Peclet number. Transversal retention of both inert and reactive solutes is reflected in terms of the tail of the breakthrough curve. Especially, reactive solutes can have a substantial magnification of the tailing behaviour depending on reaction rates or partitioning coefficients. To accurately discriminate between the effects of reactions and hydromechanical mixing its is relevant to use simultaneous injections of inert and reactive tracers with a sequential or integrated evaluation procedure. As an example, the slope of the P-32 tailing is consistently smaller than that of a simultaneous tritium injection in Ekeby wetland, Eskilstuna. The same applies to N-15 injected in the same experiment, but nitrogen is affected also by a systematic loss due to denitrification. Uptake in stream-bed sediments can be caused by a pumping effect arising when a variable pressure field is created on the stream bottom due to bed

  3. Halon-1301, a new Groundwater Age Tracer

    Science.gov (United States)

    Beyer, Monique; van der Raaij, Rob; Morgenstern, Uwe; Jackson, Bethanna

    2015-04-01

    Groundwater dating is an important tool to assess groundwater resources in regards to direction and time scale of groundwater flow and recharge and to assess contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However ambiguous age interpretations are often faced, due to a limited set of available tracers and limitations of each tracer method when applied alone. There is a need for additional, complementary groundwater age tracers. We recently discovered that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate [Beyer et al, 2014]. Halon-1301 can be determined along with SF6, SF5CF3 and CFC-12 in groundwater using a gas chromatography setup with attached electron capture detector developed by Busenberg and Plummer [2008]. Halon-1301 has not been assessed in groundwater. This study assesses the behaviour of Halon-1301 in water and its suitability as a groundwater age tracer. We determined Halon-1301 in 17 groundwater and various modern (river) waters sites located in 3 different groundwater systems in the Wellington Region, New Zealand. These waters have been previously dated with tritium, CFC-12, CFC-11 and SF6 with mean residence times ranging from 0.5 to over 100 years. The waters range from oxic to anoxic and some show evidence of CFC contamination or degradation. This allows us to assess the different properties affecting the suitability of Halon-1301 as groundwater age tracer, such as its conservativeness in water and local contamination potential. The samples are analysed for Halon-1301 and SF6simultaneously, which allows identification of issues commonly faced when using gaseous tracers such as contamination with modern air during sampling. Overall we found in the assessed groundwater samples Halon-1301 is a feasible new groundwater tracer. No sample indicated significantly elevated

  4. Laplace transform in tracer kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Hauser, Eliete B., E-mail: eliete@pucrs.br [Instituto do Cerebro (InsCer/FAMAT/PUC-RS), Porto Alegre, RS, (Brazil). Faculdade de Matematica

    2013-07-01

    The main objective this paper is to quantify the pharmacokinetic processes: absorption, distribution and elimination of radiopharmaceutical(tracer), using Laplace transform method. When the drug is administered intravenously absorption is complete and is available in the bloodstream to be distributed throughout the whole body in all tissues and fluids, and to be eliminated. Mathematical modeling seeks to describe the processes of distribution and elimination through compartments, where distinct pools of tracer (spatial location or chemical state) are assigned to different compartments. A compartment model is described by a system of differential equations, where each equation represents the sum of all the transfer rates to and from a specific compartment. In this work a two-tissue irreversible compartment model is used for description of tracer, [{sup 18}F]2-fluor-2deoxy-D-glucose. In order to determine the parameters of the model, it is necessary to have information about the tracer delivery in the form of an input function representing the time-course of tracer concentration in arterial blood or plasma. We estimate the arterial input function in two stages and apply the Levenberg-Marquardt Method to solve nonlinear regressions. The transport of FDG across de arterial blood is very fast in the first ten minutes and then decreases slowly. We use de Heaviside function to represent this situation and this is the main contribution of this study. We apply the Laplace transform and the analytical solution for two-tissue irreversible compartment model is obtained. The only approach is to determinate de arterial input function. (author)

  5. An inexpensive field fluorometer for hydrogeological tracer tests with three tracers and turbidity measurement

    OpenAIRE

    Schnegg, Pierre-André

    2005-01-01

    The Geomagnetism Group of the University of Neuchâtel has recently designed a flow-through field fluorometer with added spectral capabilities for hydrological tracer tests. This instrument is equipped with four optical axes allowing water sample illumination with four independent light sources at different wavelenghs covering the full spectrum from UV to red. As many as three conveniently selected (dye) tracers can be simultaneously measured and separeted from a cocktail. Careful turbidity me...

  6. EVALUATION OF LEAKAGE FROM FUME HOODS USING TRACER GAS, TRACER NANOPARTICLES AND NANOPOWDER HANDLING TEST METHODOLOGIES

    OpenAIRE

    Dunn, Kevin H.; Tsai, Candace Su-Jung; Woskie, Susan R.; Bennett, James S.; Garcia, Alberto; Ellenbecker, Michael J.

    2014-01-01

    The most commonly reported control used to minimize workplace exposures to nanomaterials is the chemical fume hood. Studies have shown, however, that significant releases of nanoparticles can occur when materials are handled inside fume hoods. This study evaluated the performance of a new commercially available nano fume hood using three different test protocols. Tracer gas, tracer nanoparticle, and nanopowder handling protocols were used to evaluate the hood. A static test procedure using tr...

  7. Using predictive uncertainty analysis to optimise tracer test design and data acquisition

    Science.gov (United States)

    Wallis, Ilka; Moore, Catherine; Post, Vincent; Wolf, Leif; Martens, Evelien; Prommer, Henning

    2014-07-01

    Tracer injection tests are regularly-used tools to identify and characterise flow and transport mechanisms in aquifers. Examples of practical applications are manifold and include, among others, managed aquifer recharge schemes, aquifer thermal energy storage systems and, increasingly important, the disposal of produced water from oil and shale gas wells. The hydrogeological and geochemical data collected during the injection tests are often employed to assess the potential impacts of injection on receptors such as drinking water wells and regularly serve as a basis for the development of conceptual and numerical models that underpin the prediction of potential impacts. As all field tracer injection tests impose substantial logistical and financial efforts, it is crucial to develop a solid a-priori understanding of the value of the various monitoring data to select monitoring strategies which provide the greatest return on investment. In this study, we demonstrate the ability of linear predictive uncertainty analysis (i.e. “data worth analysis”) to quantify the usefulness of different tracer types (bromide, temperature, methane and chloride as examples) and head measurements in the context of a field-scale aquifer injection trial of coal seam gas (CSG) co-produced water. Data worth was evaluated in terms of tracer type, in terms of tracer test design (e.g., injection rate, duration of test and the applied measurement frequency) and monitoring disposition to increase the reliability of injection impact assessments. This was followed by an uncertainty targeted Pareto analysis, which allowed the interdependencies of cost and predictive reliability for alternative monitoring campaigns to be compared directly. For the evaluated injection test, the data worth analysis assessed bromide as superior to head data and all other tracers during early sampling times. However, with time, chloride became a more suitable tracer to constrain simulations of physical transport

  8. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

    This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

  9. PET tracers for somatostatin receptor imaging of neuroendocrine tumors

    DEFF Research Database (Denmark)

    Johnbeck, Camilla Bardram; Knigge, Ulrich; Kjær, Andreas

    2014-01-01

    Neuroendocrine tumors have shown rising incidence mainly due to higher clinical awareness and better diagnostic tools over the last 30 years. Functional imaging of neuroendocrine tumors with PET tracers is an evolving field that is continuously refining the affinity of new tracers in the search...... these PET tracers further....

  10. USING PERFLUOROCARBON TRACERS FOR VERIFICATION OF CAP AND COVER SYSTEMS PERFORMANCE.

    Energy Technology Data Exchange (ETDEWEB)

    HEISER,J.; SULLIVAN,T.

    2001-11-01

    The Department of Energy (DOE) Environmental Management (EM) office has committed itself to an accelerated cleanup of its national facilities. The goal is to have much of the DOE legacy waste sites remediated by 2006. This includes closure of several sites (e.g., Rocky Flats and Fernald). With the increased focus on accelerated cleanup, there has been considerable concern about long-term stewardship issues in general, and verification and long-term monitoring (LTM) of caps and covers, in particular. Cap and cover systems (covers) are vital remedial options that will be extensively used in meeting these 2006 cleanup goals. Every buried waste site within the DOE complex will require some form of cover system. These covers are expected to last from 100 to 1000 years or more. The stakeholders can be expected to focus on system durability and sustained performance. DOE EM has set up a national committee of experts to develop a long-term capping (LTC) guidance document. Covers are subject to subsidence, erosion, desiccation, animal intrusion, plant root infiltration, etc., all of which will affect the overall performance of the cover. Very little is available in terms of long-term monitoring other than downstream groundwater or surface water monitoring. By its very nature, this can only indicate that failure of the cover system has already occurred and contaminants have been transported away from the site. This is unacceptable. Methods that indicate early cover failure (prior to contaminant release) or predict approaching cover failure are needed. The LTC committee has identified predictive monitoring technologies as a high priority need for DOE, both for new covers as well as existing covers. The same committee identified a Brookhaven National Laboratory (BNL) technology as one approach that may be capable of meeting the requirements for LTM. The Environmental Research and Technology Division (ERTD) at BNL developed a novel methodology for verifying and monitoring

  11. Natural tracer profiles across argillaceous formations

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, Martin, E-mail: mazurek@geo.unibe.ch [Rock-Water Interaction, Institute of Geological Sciences, University of Bern (Switzerland); Alt-Epping, Peter [Rock-Water Interaction, Institute of Geological Sciences, University of Bern (Switzerland); Bath, Adrian [Intellisci, Willoughby on the Wolds, Loughborough LE12 6SZ (United Kingdom); Gimmi, Thomas [Rock-Water Interaction, Institute of Geological Sciences, University of Bern (Switzerland)] [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Niklaus Waber, H. [Rock-Water Interaction, Institute of Geological Sciences, University of Bern (Switzerland); Buschaert, Stephane [Andra, Parc de la Croix Blanche, 92298 Chatenay-Malabry Cedex (France); Canniere, Pierre De; Craen, Mieke De [SCK-CEN, 2400 Mol (Belgium); Gautschi, Andreas [Nagra, 5430 Wettingen (Switzerland); Savoye, Sebastien [IRSN, 92262 Fontenay-aux-Roses Cedex (France); Vinsot, Agnes [Andra, Parc de la Croix Blanche, 92298 Chatenay-Malabry Cedex (France); Wemaere, Isabelle [SCK-CEN, 2400 Mol (Belgium); Wouters, Laurent [Ondraf/Niras, 1210 Brussels (Belgium)

    2011-07-15

    Highlights: > Solute transport processes in clay and shale formations at nine sites are examined. > Conservative pore-water tracers (e.g. Cl{sup -}, {delta}{sup 18}O, {delta}{sup 2}H, He) show regular profiles. > These indicate the dominance of diffusive transport over times of 10{sup 5}-10{sup 6} years. > The contribution of vertical advection to transport is limited or negligible. > Modelled evolution times are in line with independent palaeo-hydrogeological data. - Abstract: Argillaceous formations generally act as aquitards because of their low hydraulic conductivities. This property, together with the large retention capacity of clays for cationic contaminants, has brought argillaceous formations into focus as potential host rocks for the geological disposal of radioactive and other waste. In several countries, programmes are under way to characterise the detailed transport properties of such formations at depth. In this context, the interpretation of profiles of natural tracers in pore waters across the formations can give valuable information about the large-scale and long-term transport behaviour of these formations. Here, tracer-profile data, obtained by various methods of pore-water extraction for nine sites in central Europe, are compiled. Data at each site comprise some or all of the conservative tracers: anions (Cl{sup -}, Br{sup -}), water isotopes ({delta}{sup 18}O, {delta}{sup 2}H) and noble gases (mainly He). Based on a careful evaluation of the palaeo-hydrogeological evolution at each site, model scenarios are derived for initial and boundary pore-water compositions and an attempt is made to numerically reproduce the observed tracer distributions in a consistent way for all tracers and sites, using transport parameters derived from laboratory or in situ tests. The comprehensive results from this project have been reported in . Here the results for three sites are presented in detail, but the conclusions are based on model interpretations of the

  12. Use of hydrochemistry as a standalone and complementary groundwater age tracer

    Science.gov (United States)

    Beyer, Monique; Jackson, Bethanna; Daughney, Chris; Morgenstern, Uwe; Norton, Kevin

    2016-12-01

    Groundwater age or residence time is the time water has resided in the subsurface since recharge. This can provide information on groundwater mixing and flow, and volumes of groundwater and recharge, etc. Groundwater age can be inferred from environmental tracers, such as SF6 and tritium that have a known input to groundwater and/or undergo known alteration processes in groundwater. Multiple tracers are often applied complementarily in order to increase the robustness of age interpretations. To this end, it is desirable to develop cost-effective and easily applicable age tracers/techniques to supplement the existing ones. A number of hydrochemical parameters are spatially and temporally widely available due to national and regional groundwater monitoring programmes. Their determination is cost-effective and relatively simple compared to existing age tracers. Hydrochemistry has been used as an age proxy but its use as an independent age tracer has only been demonstrated for water recharged weeks to months ago (relying on seasonal changes). This study focuses on the Lower Hutt Groundwater Zone, New Zealand, and assesses whether hydrochemistry can be used as an independent indicator of groundwater age, or if not, whether hydrochemistry can be used to complement groundwater age measurements based on other tracers. This study also examines the use of hydrochemistry as an indicator for recharge sources and weathering processes. This study shows that, when used independently, hydrochemistry could only be used as an age proxy, but in combination with tritium measurements, hydrochemistry provided useful additional constraint on age of groundwater recharged days to ∼100 years ago.

  13. Saline tracer visualized with three-dimensional electrical resistivity tomography: Field-scale spatial moment analysis

    Science.gov (United States)

    Singha, Kamini; Gorelick, Steven M.

    2005-01-01

    Cross-well electrical resistivity tomography (ERT) was used to monitor the migration of a saline tracer in a two-well pumping-injection experiment conducted at the Massachusetts Military Reservation in Cape Cod, Massachusetts. After injecting 2200 mg/L of sodium chloride for 9 hours, ERT data sets were collected from four wells every 6 hours for 20 days. More than 180,000 resistance measurements were collected during the tracer test. Each ERT data set was inverted to produce a sequence of 3-D snapshot maps that track the plume. In addition to the ERT experiment a pumping test and an infiltration test were conducted to estimate horizontal and vertical hydraulic conductivity values. Using modified moment analysis of the electrical conductivity tomograms, the mass, center of mass, and spatial variance of the imaged tracer plume were estimated. Although the tomograms provide valuable insights into field-scale tracer migration behavior and aquifer heterogeneity, standard tomographic inversion and application of Archie's law to convert electrical conductivities to solute concentration results in underestimation of tracer mass. Such underestimation is attributed to (1) reduced measurement sensitivity to electrical conductivity values with distance from the electrodes and (2) spatial smoothing (regularization) from tomographic inversion. The center of mass estimated from the ERT inversions coincided with that given by migration of the tracer plume using 3-D advective-dispersion simulation. The 3-D plumes seen using ERT exhibit greater apparent dispersion than the simulated plumes and greater temporal spreading than observed in field data of concentration breakthrough at the pumping well.

  14. Characterization of shallow geothermal efficiency in fractured media through thermal tracer tests and numerical modeling

    Science.gov (United States)

    de La Bernardie, Jérôme; Bour, Olivier; de Dreuzy, Jean-Raynald; Guihéneuf, Nicolas; Chatton, Eliot; Labasque, Thierry; Le Borgne, Tanguy

    2017-04-01

    Geothermal energy is a renewable energy source particularly attractive due to associated low greenhouse gas emission rates. Crystalline rocks are in general considered of poor interest for geothermal applications at shallow depths (energy storage at these shallow depths is still remaining very challenging because of the low storativity of the medium. Within this framework, the purpose of this study is to test the possibility of efficient thermal energy storage in shallow fractured rocks. For doing so, several heat tracer tests have been carried on in a single well between two connected fractures. We completed this experimental work with numerical modeling of thermal transport in fractures embedded in an impermeable conductive matrix. The thermal tracer tests were achieved in a crystalline rock aquifer at the experimental site of Ploemeur (H+ observatory network). The experimental setup consists in injecting hot water in a fracture isolated by a double straddle packer in the borehole while pumping and monitoring the temperature in a fracture crossing the same borehole at greater elevation. Several tracer tests were achieved at different pumping and injection rates. This experimental set up allowed to estimate temperature breakthrough for different tracer test durations and hydraulic configurations from fully convergent to perfect dipole tracer tests. Thanks to those tests and numerical modeling of heat transport in fractures, we demonstrate that temperature recovery is highly dependent on flow rate and streamlines shape. Thus, thermal storage rate is inversely proportional to flow and is maximized in perfect dipole configuration. These thermal tracer tests and numerical modeling allow to define the most efficient configuration for optimizing shallow geothermal storage in fractured rock.

  15. Optofluidic ring resonator sensors for rapid DNT vapor detection.

    Science.gov (United States)

    Sun, Yuze; Liu, Jing; Frye-Mason, Greg; Ja, Shiou-jyh; Thompson, Aaron K; Fan, Xudong

    2009-07-01

    We demonstrated rapid 2,4-dinitrotoluene (DNT) vapor detection at room temperature based on an optofluidic ring resonator (OFRR) sensor. With the unique on-column separation and detection features of OFRR vapor sensors, DNT can be identified from other interferences coexisting in the analyte sample mixture, which is especially useful in the detection of explosives from practical complicated vapor samples usually containing more volatile analytes. The DNT detection limit is approximately 200 pg, which corresponds to a solid phase microextraction (SPME) sampling time of only 1 second at room temperature from equilibrium headspace. A theoretical analysis was also performed to account for the experimental results. Our study shows that the OFRR vapor sensor is a promising platform for the development of a rapid, low-cost, and portable analytical device for explosive detection and monitoring.

  16. A New Way to Study Water-Vapor Absorption Coefficient

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In the visible spectrum, the atmospheric attenuations to sunlight mainly include aerosol scattering, atmospheric molecule Rayleigh scattering and ozone absorption, while in the near-infrared spectrum (from 650 nm to 1000 nm), we must take water-vapor absorption into account. Based on the atmospheric correction theory, using spectrum irradiance data measured by Instantaneous Ground spectrometer, ozone content measured by Microtops Ⅱ ozone monitor,water-vapor content and aerosol optical thickness measured by sun photometer, we give a new way to study water-vapor absorption to sunlight, and the result shows that the main peak values of water-vapor absorption coefficients are 0.025 cm-1, 0.073 cm-1, 0.124 cm-1, 0.090 cm-1, 0.141cm-1 and 0.417 cm-1, which respectively lie at 692 nm, 725 nm, 761 nm, 818 nm, 912 nm and 937 nm.

  17. Molecular hydrogen as a mesospheric hydrogen reservoir; evidence from tracer-tracer interrelationships in descended air measured within the northern polar stratospheric vortex

    Science.gov (United States)

    Meredith, L. K.; Ray, E. A.; Moore, F. L.; Plumb, R. A.

    2010-12-01

    The distribution and partitioning of all hydrogen-carrying species in and above the mesosphere inform our understanding of upper atmospheric chemistry and transport; however, many species are not easily measured. Molecular hydrogen (H2) is described as a mesospheric reservoir of hydrogen atoms released from methane (CH4) oxidation and water vapor (H2O) photolysis. Only limited indirect measurements and modeling studies have provided evidence for this reservoir until now. Measuring air that descends from upper levels within polar stratospheric vortices provides a unique opportunity to sample the chemical composition of the mesosphere at more accessible stratospheric altitudes. Such measurements were made of atmospheric H2 by the balloonborne, in situ Lightweight Airborne Chromatograph Experiment (LACE) instrument during the 1999-2000 SAGE III Ozone Loss and Validation Experiment (SOLVE). Vertical profiles of a number of tracers were made in November 1999 after the vortex formation and again in March 2000 just before vortex breakup. The tropospheric-stratospheric H2 profile shifted dramatically from being vertically uniform (~0.5 ppm) in the young vortex to exhibiting distinct minimum (~0.4 ppm) and maximum (~1 ppm) peak features after a winter of mixing and descent in the late polar vortex. Both observational and model results show that a significant fraction of mesospheric air was present in the late vortex, suggesting that the late vortex H2 features were of mesospheric origin. The goal of this study is to determine whether the chemical measurements made with LACE confirm the anticipated H2 mixing ratio peak in the mesosphere. Tracer-tracer interrelationships of H2 with concurrently measured tracers, such as SF6, CO, N2O, and CFCs, are used to determine the original altitude and mixing ratio of the H2 peak. A simple model of mixing and descent within the vortex will be used to infer the altitude distribution of H2 in the mesosphere by forcing its consistency with

  18. Tracer Diffusion Mechanism in Amorphous Solids

    Directory of Open Access Journals (Sweden)

    P. K. Hung

    2011-01-01

    Full Text Available Tracer diffusion in amorphous solid is studied by mean of nB-bubble statistic. The nB-bubble is defined as a group of atoms around a spherical void and large bubble that represents a structural defect which could be eliminated under thermal annealing. It was found that amorphous alloys such as CoxB100−x (x=90, 81.5 and 70 and Fe80P20 suffer from a large number of vacancy bubbles which function like diffusion vehicle. The concentration of vacancy bubble weakly depends on temperature, but essentially on the relaxation degree of considered sample. The diffusion coefficient estimated for proposed mechanism via vacancy bubbles is in a reasonable agreement with experiment for actual amorphous alloys. The relaxation effect for tracer diffusion in amorphous alloys is interpreted by the elimination of vacancy bubbles under thermal annealing.

  19. The medical applications of radioactive tracers

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, J.G.

    1947-12-31

    This report provides a broad yet in depth overview of the use of radioactive materials as tracers in medicine and biology for the period of 1935--1947. Particular attention is paid to is of radio-sodium, radio-iodine, radio-iron, radio-phosphorus, radio-strontium, and fission products. The main thrust of this paper is human rather than animal work and focuses in work that has been published.

  20. Molecules as tracers of galaxy evolution

    DEFF Research Database (Denmark)

    Costagliola, F.; Aalto, S.; I. Rodriguez, M.;

    2011-01-01

    We investigate the molecular gas properties of a sample of 23 galaxies in order to find and test chemical signatures of galaxy evolution and to compare them to IR evolutionary tracers. Observation at 3 mm wavelengths were obtained with the EMIR broadband receiver, mounted on the IRAM 30 m telesco...... detect the molecule in its vibrationally excited state.We find low HNC/HCN line ratios (...

  1. An Advanced Reservoir Simulator for Tracer Transport in Multicomponent Multiphase Compositional Flow and Applications to the Cranfield CO2 Sequestration Site

    Science.gov (United States)

    Moortgat, J.

    2015-12-01

    Reservoir simulators are widely used to constrain uncertainty in the petrophysical properties of subsurface formations by matching the history of injection and production data. However, such measurements may be insufficient to uniquely characterize a reservoir's properties. Monitoring of natural (isotopic) and introduced tracers is a developing technology to further interrogate the subsurface for applications such as enhanced oil recovery from conventional and unconventional resources, and CO2 sequestration. Oak Ridge National Laboratory has been piloting this tracer technology during and following CO2 injection at the Cranfield, Mississippi, CO2 sequestration test site. Two campaigns of multiple perfluorocarbon tracers were injected together with CO2 and monitored at two wells at 68 m and 112 m from the injection site. The tracer data suggest that multiple CO2 flow paths developed towards the monitoring wells, indicative of either channeling through high permeability pathways or of fingering. The results demonstrate that tracers provide an important complement to transient pressure data. Numerical modeling is essential to further explain and interpret the observations. To aid the development of tracer technology, we enhanced a compositional multiphase reservoir simulator to account for tracer transport. Our research simulator uses higher-order finite element (FE) methods that can capture the small-scale onset of fingering on the coarse grids required for field-scale modeling, and allows for unstructured grids and anisotropic heterogeneous permeability fields. Mass transfer between fluid phases and phase behavior are modeled with rigorous equation-of-state based phase-split calculations. We present our tracer simulator and preliminary results related to the Cranfield experiments. Applications to noble gas tracers in unconventional resources are presented by Darrah et al.

  2. Very Massive Tracers and Higher Derivative Biases

    CERN Document Server

    Fujita, Tomohiro; Senatore, Leonardo; Vlah, Zvonimir; Angulo, Raul

    2016-01-01

    Most of the upcoming cosmological information will come from analyzing the clustering of the Large Scale Structures (LSS) of the universe through LSS or CMB observations. It is therefore essential to be able to understand their behavior with exquisite precision. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a consistent framework to make predictions for LSS observables in the mildly non-linear regime. In this paper we focus on biased tracers. We argue that in calculations at a given order in the dark matter perturbations, highly biased tracers will underperform because of their larger higher derivative biases. A natural prediction of the EFTofLSS is therefore that by simply adding higher derivative biases, all tracers should perform comparably well. We implement this prediction for the halo-halo and the halo-matter power spectra at one loop, and the halo-halo-halo, halo-halo-matter, and halo-matter-matter bispectra at tree-level, and compare with simulations. We find good agreement ...

  3. Tracer technology modeling the flow of fluids

    CERN Document Server

    Levenspiel, Octave

    2012-01-01

    A vessel’s behavior as a heat exchanger, absorber, reactor, or other process unit is dependent upon how fluid flows through the vessel.  In early engineering, the designer would assume either plug flow or mixed flow of the fluid through the vessel.  However, these assumptions were oftentimes inaccurate, sometimes being off by a volume factor of 100 or more.  The result of this unreliable figure produced ineffective products in multiple reaction systems.   Written by a pioneering researcher in the field of chemical engineering, the tracer method was introduced to provide more accurate flow data.  First, the tracer method measured the actual flow of fluid through a vessel.  Second, it developed a suitable model to represent the flow in question.  Such models are used to follow the flow of fluid in chemical reactors and other process units, like in rivers and streams, or solid and porous structures.  In medicine, the tracer method is used to study the flow of chemicals—harmful  and harmless—in the...

  4. Advancing Reactive Tracer Methods for Measurement of Thermal Evolution in Geothermal Reservoirs: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell A. Plummer; Carl D. Palmer; Earl D. Mattson; Laurence C. Hull; George D. Redden

    2011-07-01

    The injection of cold fluids into engineered geothermal system (EGS) and conventional geothermal reservoirs may be done to help extract heat from the subsurface or to maintain pressures within the reservoir (e.g., Rose et al., 2001). As these injected fluids move along fractures, they acquire heat from the rock matrix and remove it from the reservoir as they are extracted to the surface. A consequence of such injection is the migration of a cold-fluid front through the reservoir (Figure 1) that could eventually reach the production well and result in the lowering of the temperature of the produced fluids (thermal breakthrough). Efficient operation of an EGS as well as conventional geothermal systems involving cold-fluid injection requires accurate and timely information about thermal depletion of the reservoir in response to operation. In particular, accurate predictions of the time to thermal breakthrough and subsequent rate of thermal drawdown are necessary for reservoir management, design of fracture stimulation and well drilling programs, and forecasting of economic return. A potential method for estimating migration of a cold front between an injection well and a production well is through application of reactive tracer tests, using chemical whose rate of degradation is dependent on the reservoir temperature between the two wells (e.g., Robinson 1985). With repeated tests, the rate of migration of the thermal front can be determined, and the time to thermal breakthrough calculated. While the basic theory behind the concept of thermal tracers has been understood for some time, effective application of the method has yet to be demonstrated. This report describes results of a study that used several methods to investigate application of reactive tracers to monitoring the thermal evolution of a geothermal reservoir. These methods included (1) mathematical investigation of the sensitivity of known and hypothetical reactive tracers, (2) laboratory testing of novel

  5. Use of tracers for mud filtrate and completion fluid invasion studies

    Energy Technology Data Exchange (ETDEWEB)

    Kleven, Reidun [Statoil DDB, Bergen (Norway); Dahl, John Blessum; Bjoernstad, Tor; Qvenild, Carsten; Tollan, Odd [Institutt for energiteknikk, Kjeller (Norway)

    1996-09-30

    The objectives of this work are (1): to study sorption/desorption of mud filtrate ions near the wellbore region by using water sampled with a formation tester equipment (FTE); (2) to study sorption/desorption of ions in the mud filtrate and the completion fluid by monitoring the ionic composition of produced water; (3) to determine the fraction of mud filtrate and completion fluid water in produced water; and (4) develop a suitable and safe tracer method. A tracer method was developed to measure sorption/desorption of various ions infiltrating the reservoir during drilling and completion of a well. Tritiated water (HTO) was used to tag the mud filtrate and bromide ion (Br{sup -}) to tag the completion fluid. The measurements are based on analysis of FTE and produced water samples. The ionic concentrations observed are compared with corresponding `no sorption/desorption` concentration values determined theoretically. Special attention is paid to the `tracer diagram` of an open well, because a `no sorption/desorption curve` can be expressed in a straight line in a linear coordinate system. Observed deviations from these curves show that sorption/desorption processes have taken place. The tracer method presented was useful to determine the distribution of ions in the pore-water/sedimentary rock system near the wellbore

  6. Estimating kinetic mass transfer by resting-period measurements in flow-interruption tracer tests.

    Science.gov (United States)

    Gong, R; Lu, C; Wu, W-M; Cheng, H; Gu, B; Watson, D B; Criddle, C S; Kitanidis, P K; Brooks, S C; Jardine, P M; Luo, J

    2010-09-20

    Flow-interruption tracer test is an effective approach to identify kinetic mass transfer processes for solute transport in subsurface media. By switching well pumping and resting, one may alter the dominant transport mechanism and generate special concentration patterns for identifying kinetic mass transfer processes. In the present research, we conducted three-phase (i.e., pumping, resting, and pumping) field-scale flow-interruption tracer tests using a conservative tracer bromide in a multiple-well system installed at the US Department of Energy Site, Oak Ridge, TN. A novel modeling approach based on the resting-period measurements was developed to estimate the mass transfer parameters. This approach completely relied on the measured breakthrough curves without requiring detailed aquifer characterization and solving transport equations in nonuniform, transient flow fields. Additional measurements, including hydraulic heads and tracer concentrations in large pumping wells, were taken to justify the assumption that mass transfer processes dominated concentration change during resting periods. The developed approach can be conveniently applied to any linear mass transfer model. Both first-order and multirate mass transfer models were applied to analyze the breakthrough curves at various monitoring wells. The multirate mass transfer model was capable of jointly fitting breakthrough curve behavior, showing the effectiveness and flexibility for incorporating aquifer heterogeneity and scale effects in upscaling effective mass transfer models.

  7. Asian Tracer Experiment and Atmospheric Modeling (TEAM) Project: Draft Field Work Plan for the Asian Long-Range Tracer Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Allwine, K Jerry; Flaherty, Julia E.

    2007-08-01

    This report provides an experimental plan for a proposed Asian long-range tracer study as part of the international Tracer Experiment and Atmospheric Modeling (TEAM) Project. The TEAM partners are China, Japan, South Korea and the United States. Optimal times of year to conduct the study, meteorological measurements needed, proposed tracer release locations, proposed tracer sampling locations and the proposed durations of tracer releases and subsequent sampling are given. Also given are the activities necessary to prepare for the study and the schedule for completing the preparation activities leading to conducting the actual field operations. This report is intended to provide the TEAM members with the information necessary for planning and conducting the Asian long-range tracer study. The experimental plan is proposed, at this time, to describe the efforts necessary to conduct the Asian long-range tracer study, and the plan will undoubtedly be revised and refined as the planning goes forward over the next year.

  8. A Systematic Approach for Developing Bacteria-Specific Imaging Tracers.

    Science.gov (United States)

    Ordonez, Alvaro A; Weinstein, Edward A; Bambarger, Lauren E; Saini, Vikram; Chang, Yong S; DeMarco, Vincent P; Klunk, Mariah H; Urbanowski, Michael E; Moulton, Kimberly L; Murawski, Allison M; Pokkali, Supriya; Kalinda, Alvin S; Jain, Sanjay K

    2017-01-01

    The modern patient is increasingly susceptible to bacterial infections including those due to multidrug-resistant organisms (MDROs). Noninvasive whole-body analysis with pathogen-specific imaging technologies can significantly improve patient outcomes by rapidly identifying a source of infection and monitoring the response to treatment, but no such technology exists clinically. We systematically screened 961 random radiolabeled molecules in silico as substrates for essential metabolic pathways in bacteria, followed by in vitro uptake in representative bacteria-Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and mycobacteria. Fluorine-labeled analogs, that could be developed as PET-based imaging tracers, were evaluated in a murine myositis model. We identified 3 novel, nontoxic molecules demonstrating selective bacterial uptake: para-aminobenzoic acid (PABA), with uptake in all representative bacteria including Mycobacterium tuberculosis; mannitol, with selective uptake in S. aureus and E. coli; and sorbitol, accumulating only in E. coli None accumulated in mammalian cells or heat-killed bacteria, suggesting metabolism-derived specificity. In addition to an extended bacterial panel of laboratory strains, all 3 molecules rapidly accumulated in respective clinical isolates of interest including MDROs such as methicillin-resistant S. aureus, extended-spectrum β-lactamase-producing, and carbapenem-resistant Enterobacteriaceae. In a murine myositis model, fluorine-labeled analogs of all 3 molecules could rapidly detect and differentiate infection sites from sterile inflammation in mice (P = 0.03). Finally, 2-deoxy-2-[F-18]fluoro-d-sorbitol ((18)F-FDS) can be easily synthesized from (18)F-FDG. PET, with (18)F-FDS synthesized using current good manufacturing practice, could rapidly differentiate true infection from sterile inflammation to selectively localize E. coli infection in mice. We have developed a systematic approach that exploits unique

  9. Designing polymer surfaces via vapor deposition

    Directory of Open Access Journals (Sweden)

    Ayse Asatekin

    2010-05-01

    Full Text Available Chemical Vapor Deposition (CVD methods significantly augment the capabilities of traditional surface modification techniques for designing polymeric surfaces. In CVD polymerization, the monomer(s are delivered to the surface through the vapor phase and then undergo simultaneous polymerization and thin film formation. By eliminating the need to dissolve macromolecules, CVD enables insoluble polymers to be coated and prevents solvent damage to the substrate. Since de-wetting and surface tension effects are absent, CVD coatings conform to the geometry of the underlying substrate. Hence, CVD polymers can be readily applied to virtually any substrate: organic, inorganic, rigid, flexible, planar, three-dimensional, dense, or porous. CVD methods integrate readily with other vacuum processes used to fabricate patterned surfaces and devices. CVD film growth proceeds from the substrate up, allowing for interfacial engineering, real-time monitoring, thickness control, and the synthesis of films with graded composition. This article focuses on two CVD polymerization methods that closely translate solution chemistry to vapor deposition; initiated CVD and oxidative CVD. The basic concepts underlying these methods and the resultant advantages over other thin film coating techniques are described, along with selected applications where CVD polymers are an enabling technology.

  10. A parameter identifiability study of two chalk tracer tests

    Directory of Open Access Journals (Sweden)

    S. A. Mathias

    2006-08-01

    Full Text Available As with most fractured rock formations, Chalk is highly heterogeneous. Therefore, meaningful estimates of model parameters must be obtained at a scale comparable with the process of concern. These are frequently obtained by calibrating an appropriate model to observed concentration-time data from radially convergent tracer tests (RCTT. Arguably, an appropriate model should consider radially convergent dispersion (RCD and Fickian matrix diffusion. Such a model requires the estimation of at least four parameters. A question arises as to whether or not this level of model complexity is supported by the information contained within the calibration data. Generally modellers have not answered this question due to the calibration techniques employed. A dual-porosity model with RCD was calibrated to two tracer test datasets from different UK Chalk aquifers. A multivariate sensitivity analysis, which assumed only a priori upper and lower bounds for each model parameter, was undertaken. Rather than looking at measures of uncertainty, the shape of the multivariate objective function surface was used to determine whether a parameter was identifiable. Non-identifiable parameters were then removed and the procedure was repeated until all remaining parameters were identifiable.

    It was found that the single fracture model (SFM (which ignores mechanical dispersion obtained the best mass recovery, excellent model performance and best parameter identifiability in both the tests studied. However, there was no objective evidence suggesting that mechanical dispersion was negligible. Moreover, the SFM (with just two parameters was found to be good at approximating the Single Fracture Dispersion Model SFDM (with three parameters when different, and potentially erroneous parameters, were used. Overall, this study emphasises the importance of adequate temporal sampling of breakthrough curve data prior to peak concentrations, to ensure adequate characterisation of

  11. Groundwater surface water interaction study using natural isotopes tracer

    Science.gov (United States)

    Yoon, Yoon Yeol; Kim, Yong Chul; Cho, Soo Young; Lee, Kil Yong

    2015-04-01

    Tritium and stable isotopes are a component of the water molecule, they are the most conservative tracer for groundwater study. And also, radon is natural radioactive nuclide and well dissolved in groundwater. Therefore, these isotopes are used natural tracer for the study of surface water and groundwater interaction of water curtain greenhouse area. The study area used groundwater as a water curtain for warming tool of greenhouse during the winter, and is associated with issues of groundwater shortage while being subject to groundwater-river water interaction. During the winter time, these interactions were studied by using Rn-222, stable isotopes and H-3. These interaction was monitored in multi depth well and linear direction well of groundwater flow. And dam effect was also compared. Samples were collected monthly from October 2013 to April 2014. Radon and tritium were analyzed using Quantulus low background liquid scintillation counter and stable isotopes were analyzed using an IRIS (Isotope Ratio Infrared Spectroscopy ; L2120-i, Picarro). During the winter time, radon concentration was varied from 0.07 Bq/L to 8.9 Bq/L and different interaction was showed between dam. Surface water intrusion was severe at February and restored April when greenhouse warming was ended. The stable isotope results showed different trend with depth and ranged from -9.16 ‰ to -7.24 ‰ for δ 18O value, while the δD value was ranged from -57.86 ‰ to -50.98 ‰. The groundwater age as dated by H-3 was ranged 0.23 Bq/L - 0.59 Bq/L with an average value of 0.37 Bq/L.

  12. Solvents and vapor intrusion pathways.

    Science.gov (United States)

    Phillips, Scott D; Krieger, Gary R; Palmer, Robert B; Waksman, Javier C

    2004-08-01

    Vapor intrusion must be recognized appropriately as a separate pathway of contamination. Although many issues resemble those of other forms of contamination (particularly its entryway, which is similar to that of radon seepage), vapor intrusion stands apart as a unique risk requiring case-specific action. This article addresses these issues and the current understanding of the most appropriate and successful remedial actions.

  13. Magnetic resonance imaging of slow water flow during infiltration and evaporation by tracer motion

    Science.gov (United States)

    Pohlmeier, A.; Haber-Pohlmeier, S.; Bechtold, M.; Vanderborght, J.; Vereecken, H.

    2012-04-01

    Water fluxes in soils control many processes in the environment like plant nutrition, solute and pollutant transport. In the last two decades non-invasive visualization methods have been adapted to monitor flux processes on the small scale. Magnetic resonance imaging (MRI), also well known from medical diagnostics, is one of the most versatile ones. It mostly probes directly the substance of interest: water, and it offers many opportunities to manipulate the observed signals for creating different contrasts and thus probing different properties of the porous medium and the embedded fluids. For example, one can make the signal sensitive to the total proton density, i. e. water content, to spatial distributions of relaxation times which reflect pore sizes, to spatial distributions of transport coefficients, and to concentration of contrast agents by using strongly T1 weighted MRI pulse sequences. In this presentation we use GdDTPA2- for monitoring flux processes in soil columns in an ultra-wide bore MRI scanner. It offers the opportunity for monitoring slow water fluxes mainly occurring in soil systems which are not monitorable with direct MRI flow imaging. This contrast agent is most convenient since it behaves conservatively, i.e. it does not sorb at different soil materials and it is chemically stable. Firstly, we show that its mode of action in natural porous media is identical to that known from medical applications as proved by the identical relaxivity parameters [1]. Secondly, the tracer is applied for the visualization of flux processes during evaporation-driven flow. Theoretical considerations by forward simulation predicted a lateral redistribution of solutes during evaporative upward fluxes from highly conductive fine material to neighbouring domains with low water content and conductivity. Here we could prove that such near-surface redistribution really takes place [2]. Thirdly, this tracer is applied for the investigation of water uptake by root systems

  14. Iron bromide vapor laser

    Science.gov (United States)

    Sukhanov, V. B.; Shiyanov, D. V.; Trigub, M. V.; Dimaki, V. A.; Evtushenko, G. S.

    2016-03-01

    We have studied the characteristics of a pulsed gas-discharge laser on iron bromide vapor generating radiation with a wavelength of 452.9 nm at a pulse repetition frequency (PRF) of 5-30 kHz. The maximum output power amounted to 10 mW at a PRF within 5-15 kHz for a voltage of 20-25 kV applied to electrodes of the discharge tube. Addition of HBr to the medium produced leveling of the radial profile of emission. Initial weak lasing at a wavelength of 868.9 nm was observed for the first time, which ceased with buildup of the main 452.9-nm line.

  15. Vapor phase heat transport systems

    Energy Technology Data Exchange (ETDEWEB)

    Hedstrom, J.C.; Neeper, D.A.

    1985-09-01

    This report describes progress in theoretical and experimental investigations of various forms of a vapor transport system for solar space heating, which could also be applied to service water heating. Refrigerant is evaporated in a solar collector, which may be located on the external wall or roof of a building. The vapor is condensed in a passively discharged thermal storage unit located within the building. The condensed liquid can be returned to the collector either by a motor-driven pump or by a completely passive self-pumping mechanism in which the vapor pressure lifts the liquid from the condenser to the collector. The theoretical investigation analyzes this self-pumping scheme. Experiments in solar test cells compare the operation of both passive and active forms of the vapor system with the operation of a passive water wall. The vapor system operates as expected, with potential advantages over other passive systems in design flexibility and energy yield.

  16. 33 CFR 154.828 - Vapor recovery and vapor destruction units.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vapor recovery and vapor... SECURITY (CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.828 Vapor recovery and vapor destruction units. (a) The inlet to a vapor recovery unit...

  17. CityFlux perfluorocarbon tracer experiments

    Science.gov (United States)

    Petersson, F. K.; Martin, D.; White, I. R.; Henshaw, S. J.; Nickless, G.; Longley, I.; Percival, C. J.; Gallagher, M.; Shallcross, D. E.

    2010-07-01

    In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m. The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site. Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail. The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this. The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

  18. CityFlux perfluorocarbon tracer experiments

    Directory of Open Access Journals (Sweden)

    F. K. Petersson

    2010-01-01

    Full Text Available In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m.

    The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site.

    Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail.

    The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this.

    The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

  19. CityFlux perfluorocarbon tracer experiments

    Directory of Open Access Journals (Sweden)

    F. K. Petersson

    2010-07-01

    Full Text Available In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m.

    The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site.

    Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail.

    The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this.

    The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

  20. Modeling of CBM production, CO2 injection, and tracer movement at a field CO2 sequestration site

    Energy Technology Data Exchange (ETDEWEB)

    Siriwardane, Hema J.; Bowes, Benjamin D.; Bromhal, Grant S.; Gondle, Raj K.; Wells, Arthur W.; Strazisar, Brian R.

    2012-07-01

    Sequestration of carbon dioxide in unmineable coal seams is a potential technology mainly because of the potential for simultaneous enhanced coalbed methane production (ECBM). Several pilot tests have been performed around the globe leading to mixed results. Numerous modeling efforts have been carried out successfully to model methane production and carbon dioxide (CO{sub 2}) injection. Sensitivity analyses and history matching along with several optimization tools were used to estimate reservoir properties and to investigate reservoir performance. Geological and geophysical techniques have also been used to characterize field sequestration sites and to inspect reservoir heterogeneity. The fate and movement of injected CO{sub 2} can be determined by using several monitoring techniques. Monitoring of perfluorocarbon (PFC) tracers is one of these monitoring technologies. As a part of this monitoring technique, a small fraction of a traceable fluid is added to the injection wellhead along with the CO{sub 2} stream at different times to monitor the timing and location of the breakthrough in nearby monitoring wells or offset production wells. A reservoir modeling study was performed to simulate a pilot sequestration site located in the San Juan coal basin of northern New Mexico. Several unknown reservoir properties at the field site were estimated by modeling the coal seam as a dual porosity formation and by history matching the methane production and CO{sub 2} injection. In addition to reservoir modeling of methane production and CO{sub 2} injection, tracer injection was modeled. Tracers serve as a surrogate for determining potential leakage of CO{sub 2}. The tracer was modeled as a non-reactive gas and was injected into the reservoir as a mixture along with CO{sub 2}. Geologic and geometric details of the field site, numerical modeling details of methane production, CO{sub 2} injection, and tracer injection are presented in this paper. Moreover, the numerical

  1. Vapor pressure measured with inflatable plastic bag

    Science.gov (United States)

    1965-01-01

    Deflated plastic bag in a vacuum chamber measures initial low vapor pressures of materials. The bag captures the test sample vapors and visual observation of the vapor-inflated bag under increasing external pressures yields pertinent data.

  2. A Citizen's Guide to Vapor Intrusion Mitigation

    Science.gov (United States)

    This guide describes how vapor intrusion is the movement of chemical vapors from contaminated soil and groundwater into nearby buildings.Vapors primarily enter through openings in the building foundation or basement walls.

  3. A Lithium Vapor Box similarity experiment employing water vapor

    Science.gov (United States)

    Schwartz, Ja; Jagoe, C.; Goldston, Rj; Jaworski, Ma

    2016-10-01

    Handling high power loads and heat flux in the divertor is a major challenge for fusion power plants. A detached plasma will likely be required. However, hydrogenic and impurity puffing experiments show that detached operation leads easily to X-point MARFEs, impure plasmas, degradation in confinement, and lower helium pressure at the exhaust. The concept of the Lithium Vapor Box Divertor is to use local evaporation and strong differential pumping through condensation to localize the gas-phase material that absorbs the plasma heat flux, and so avoid those difficulties. In order to design such a box first the vapor without plasma must be simulated. The density of vapor required can be estimated using the SOL power, major radius, poloidal box length, and cooling energy per lithium atom. For an NSTX-U-sized machine, the Knudsen number Kn spans 0.01 to 1, the transitional flow regime. This regime cannot handled by fluid codes or collisionless Monte Carlo codes, but can be handled by Direct Simulation Monte Carlo (DSMC) codes. To validate a DSMC model, we plan to build a vapor box test stand employing more-convenient water vapor instead of lithium vapor as the working fluid. Transport of vapor between the chambers at -50C will be measured and compared to the model. This work supported by DOE Contract No. DE-AC02-09CH11466.

  4. Safety assessment of in-vessel vapor explosion loads in next generation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang Hyun; Cho, Jong Rae; Choi, Byung Uk; Kim, Ki Yong; Lee, Kyung Jung [Korea Maritime University, Busan (Korea); Park, Ik Kyu [Seoul National University, Seoul (Korea)

    1998-12-01

    A safety assessment of the reactor vessel lower head integrity under in-vessel vapor explosion loads has been performed. The premixing and explosion calculations were performed using TRACER-II code. Using the calculated explosion pressures imposed on the lower head inner wall, strain calculations were performed using ANSYS code. The explosion analyses show that the explosion impulses are not altered significantly by the uncertain parameters of triggering location and time, fuel and vapor volume fractions in uniform premixture bounding calculations within the conservative ranges. Strain analyses using the calculated pressure loads on the lower head inner wall show that the vapor explosion-induced lower head failure is physically unreasonable. The static analysis using the conservative explosion-end pressure of 7,246 psia shows that the maximum equivalent strain is 4.3% at the bottom of lower head, which is less than the allowable threshold value of 11%. (author). 24 refs., 40 figs., 3 tabs.

  5. Bayesian belief network for CO2 leak detection by near-surface flux rates for CO2 and perfluorocarbon (PFC) tracer

    Science.gov (United States)

    Yang, Y.; Small, M. J.; Ogretim, E.; Gray, D. D.; Bromhal, G. S.; Strazisar, B. R.; Wells, A. W.

    2010-12-01

    To incorporate the use of multiple geologic sequestration monitoring techniques, a Bayesian Belief Network (BBN) for leak detection inference is applied to integrate the information provided by different techniques deployed at a site. In this study, two monitoring methods, near-surface soil CO2 flux and perfluorocarbon (PFC) tracer concentration, are included in the BBN. First, possible near-surface flux rates for CO2 and PFC tracer as a function of distance from a leakage point are simulated by TOUGH2, given different leakage rates and permeabilities. Then, the natural near-surface CO2 flux and background PFC tracer concentration measured at the Zero Emission Research and Technology (ZERT) site are used to determine critical values for leak inference and to calculate the probabilities of leak detection given a monitoring network. A BBN of leak detection is established by combing the TOUGH2 simulations and the background characterization of near-surface CO2 flux and PFC tracer at the sequestration site. The results show a positive correlation between the detection abilities of PFC tracer and soil CO2 flux, but the PFC tracer is more sensitive for detecting a leak in most cases. The BBN of leak detection including both soil CO2 flux and PFC tracer concentration gives an integrated probability estimation of leak detection for different permeability and leakage rates for a given monitoring network. A BBN developed using the proposed methodology can be used to help site engineers and decision makers to evaluate leakage signals and the risk of undetected leakage, given a suite of monitoring techniques and site conditions.

  6. Solute transport characterization in karst aquifers by tracer injection tests for a sustainable water resource management

    Science.gov (United States)

    Morales, T.; Angulo, B.; Uriarte, J. A.; Olazar, M.; Arandes, J. M.; Antiguedad, I.

    2017-04-01

    Protection of water resources is a major challenge today, given that territory occupation and land use are continuously increasing. In the case of karst aquifers, its dynamic complexity requires the use of specific methodologies that allow establishing local and regional flow and transport patterns. This information is particularly necessary when springs and wells harnessed for water supply are concerned. In view of the present state of the art, this work shows a new approach based on the use of a LiCl based tracer injection test through a borehole for transport characterization from a local to a regional scale. Thus a long term tracer injection test was conducted in a particularly sensitive sector of the Egino karst massif (Basque Country, Spain). The initial displacement of tracer in the vicinity of the injection was monitored in a second borehole at a radial distance of 10.24 m. This first information, assessed by a radial divergent model, allows obtaining transport characteristic parameters in this immediate vicinity during injection. At a larger (regional) scale, the tracer reaches a highly transmissive network with mean traveling velocities to the main springs being from 4.3 to 13.7 m/h. The responses obtained, particularly clear in the main spring used for water supply, and the persistence of part of the tracer in the injection zone, pose reconsidering the need for their protection. Thus, although the test allows establishing the 24-h isochrone, which is the ceiling value in present European vulnerability approaches, the results obtained advise widening the zone to protect in order to guarantee water quality in the springs. Overall, this stimulus-response test allows furthering the knowledge on the dynamics of solute transport in karst aquifers and is a particularly useful tool in studies related to source vulnerability and protection in such a complex medium.

  7. Quantification of conservative and reactive transport using a single groundwater tracer test in a fractured media

    Science.gov (United States)

    Chatton, Eliot; Labasque, Thierry; Guillou, Aurélie; Béthencourt, Lorine; de La Bernardie, Jérôme; Boisson, Alexandre; Koch, Florian; Aquilina, Luc

    2017-04-01

    Identification of biogeochemical reactions in aquifers and determining kinetics is important for the prediction of contaminant transport in aquifers and groundwater management. Therefore, experiments accounting for both conservative and reactive transport are essential to understand the biogeochemical reactivity at field scale. This study presents the results of a groundwater tracer test using the combined injection of dissolved conservative and reactive tracers (He, Xe, Ar, Br-, O2 and NO3-) in order to evaluate the transport properties of a fractured media in Brittany, France. Dissolved gas concentrations were continuously monitored in situ with a CF-MIMS (Chatton et al, 2016) allowing a high frequency (1 gas every 2 seconds) multi-tracer analysis (N2, O2, CO2, CH4, N2O, H2, He, Ne, Ar, Kr, Xe) over a large resolution (6 orders of magnitude). Along with dissolved gases, groundwater biogeochemistry was monitored through the sampling of major anions and cations, trace elements and microbiological diversity. The results show breakthrough curves allowing the combined quantification of conservative and reactive transport properties. This ongoing work is an original approach investigating the link between heterogeneity of porous media and biogeochemical reactions at field scale. Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour and Luc Aquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016.

  8. Boil-off gas vapors are recovered by reliquefaction in LNG

    Energy Technology Data Exchange (ETDEWEB)

    Levay, M.; Petit, P.; Paradowski, H.

    1986-02-24

    Although great care is taken to prevent heat leaks into cryogenic equipment in LNG terminals, boil-off vapors evolve from LNG stored at thermodynamic equilibrium. The quantities of boil-off vapors may be quite considerable. They account for about 1% of the total gas quantity received and sent out at the monitor-de-bretagne LNG terminal of Gaz de France. A novel process has significantly cut boil-off vapor handling costs. It is free of technical problems which would arise from local utilization of the gas and makes boil-off recovery possible under optimum conditions. In addition, the process shows an excellent degree of reliability. Boil-off vapors have a lower heating value than the stored LNG. However, since they mainly consist of methane, their economic usefulness makes vapor recovery necessary. This boil-off gas, with widely fluctuating quantities and qualities, cannot be readily used locally. The vapors must be sent out into the grid.

  9. U.S. Strategic Petroleum Reserve Vapor Pressure Committee 2009 annual report.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Ray (Allen Energy Services, Inc., Longview, TX); Eldredge, Lisa (DynMcDermott Petroleum Operations, Harahan, LA); DeLuca, Charles (DynMcDermott Petroleum Operations, Harahan, LA); Mihalik, Patrick (DynMcDermott Petroleum Operations, Harahan, LA); Maldonado, Julio (U.S. Department of Energy, Harahan, LA); Lord, David L.; Rudeen, David Keith (GRAM, Inc., Albuquerque, NM); Berndsen, Gerard (U.S. Department of Energy, Harahan, LA)

    2010-05-01

    This report comprises an annual summary of activities under the U.S. Strategic Petroleum Reserve (SPR) Vapor Pressure Committee in FY2009. The committee provides guidance to senior project management on the issues of crude oil vapor pressure monitoring nd mitigation. The principal objectives of the vapor pressure program are, in the event of an SPR drawdown, to minimize the impact on the environment and assure worker safety and public health from crude oil vapor emissions. The annual report reviews key program areas ncluding monitoring program status, mitigation program status, new developments in measurements and modeling, and path forward including specific recommendations on cavern sampling for the next year. The contents of this report were first presented to SPR senior anagement in December 2009, in a deliverable from the vapor pressure committee. The current SAND report is an adaptation for the Sandia technical audience.

  10. Compilation and analyses of results from cross-hole tracer tests with conservative tracers

    Energy Technology Data Exchange (ETDEWEB)

    Hjerne, Calle; Nordqvist, Rune; Harrstroem, Johan (Geosigma AB (Sweden))

    2010-09-15

    Radionuclide transport in hydrogeological formations is one of the key factors for the safety analysis of a future repository of nuclear waste. Tracer tests have therefore been an important field method within the SKB investigation programmes at several sites since the late 1970's. This report presents a compilation and analyses of results from cross-hole tracer tests with conservative tracers performed within various SKB investigations. The objectives of the study are to facilitate, improve and reduce uncertainties in predictive tracer modelling and to provide supporting information for SKB's safety assessment of a final repository of nuclear waste. More specifically, the focus of the report is the relationship between the tracer mean residence time and fracture hydraulic parameters, i.e. the relationship between mass balance aperture and fracture transmissivity, hydraulic diffusivity and apparent storativity. For 74 different combinations of pumping and injection section at six different test sites (Studsvik, Stripa, Finnsjoen, Aespoe, Forsmark, Laxemar), estimates of mass balance aperture from cross-hole tracer tests as well as transmissivity were extracted from reports or in the SKB database Sicada. For 28 of these combinations of pumping and injection section, estimates of hydraulic diffusivity and apparent storativity from hydraulic interference tests were also found. An empirical relationship between mass balance aperture and transmissivity was estimated, although some uncertainties for individual data exist. The empirical relationship between mass balance aperture and transmissivity presented in this study deviates considerably from other previously suggested relationships, such as the cubic law and transport aperture as suggested by /Dershowitz and Klise 2002/, /Dershowitz et al. 2002/ and /Dershowitz et al. 2003/, which also is discussed in this report. No clear and direct empirical relationship between mass balance aperture and hydraulic

  11. Design and analysis of a natural-gradient ground-water tracer test in a freshwater tidal wetland, West Branch Canal Creek, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Olsen, Lisa D.; Tenbus, Frederick J.

    2005-01-01

    A natural-gradient ground-water tracer test was designed and conducted in a tidal freshwater wetland at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The objectives of the test were to characterize solute transport at the site, obtain data to more accurately determine the ground-water velocity in the upper wetland sediments, and to compare a conservative, ionic tracer (bromide) to a volatile tracer (sulfur hexafluoride) to ascertain whether volatilization could be an important process in attenuating volatile organic compounds in the ground water. The tracer test was conducted within the upper peat unit of a layer of wetland sediments that also includes a lower clayey unit; the combined layer overlies an aquifer. The area selected for the test was thought to have an above-average rate of ground-water discharge based on ground-water head distributions and near-surface detections of volatile organic compounds measured in previous studies. Because ground-water velocities in the wetland sediments were expected to be slow compared to the underlying aquifer, the test was designed to be conducted on a small scale. Ninety-seven ?-inch-diameter inverted-screen stainless-steel piezometers were installed in a cylindrical array within approximately 25 cubic feet (2.3 cubic meters) of wetland sediments, in an area with a vertically upward hydraulic gradient. Fluorescein dye was used to qualitatively evaluate the hydrologic integrity of the tracer array before the start of the tracer test, including verifying the absence of hydraulic short-circuiting due to nonnatural vertical conduits potentially created during piezometer installation. Bromide and sulfur hexafluoride tracers (0.139 liter of solution containing 100,000 milligrams per liter of bromide ion and 23.3 milligrams per liter of sulfur hexafluoride) were co-injected and monitored to generate a dataset that could be used to evaluate solute transport in three dimensions. Piezometers were sampled 2 to 15 times

  12. Quantitative observation of tracer transport with high-resolution PET

    Science.gov (United States)

    Kulenkampff, Johannes; Gruendig, Marion; Zakhnini, Abdelhamid; Lippmann-Pipke, Johanna

    2016-04-01

    Transport processes in natural porous media are typically heterogeneous over various scales. This heterogeneity is caused by the complexity of pore geometry and molecular processes. Heterogeneous processes, like diffusive transport, conservative advective transport, mixing and reactive transport, can be observed and quantified with quantitative tomography of tracer transport patterns. Positron Emission Tomography (PET) is by far the most sensitive method and perfectly selective for positron-emitting radiotracers, therefore it is suited as reference method for spatiotemporal tracer transport observations. The number of such PET-applications is steadily increasing. However, many applications are afflicted by the low spatial resolution (3 - 5 mm) of the clinical scanners from cooperating nuclear medical departments. This resolution is low in relation to typical sample dimensions of 10 cm, which are restricted by the mass attenuation of the material. In contrast, our GeoPET-method applies a high-resolution scanner with a resolution of 1 mm, which is the physical limit of the method and which is more appropriate for samples of the size of soil columns or drill cores. This higher resolution is achieved at the cost of a more elaborate image reconstruction procedure, especially considering the effects of Compton scatter. The result of the quantitative image reconstruction procedure is a suite of frames of the quantitative tracer distribution with adjustable frame rates from minutes to months. The voxel size has to be considered as reference volume of the tracer concentration. This continuous variable includes contributions from structures far below the spatial resolution, as far as a detection threshold, in the pico-molar range, is exceeded. Examples from a period of almost 10 years (Kulenkampff et al. 2008a, Kulenkampff et al. 2008b) of development and application of quantitative GeoPET-process tomography are shown. These examples include different transport processes

  13. Improved Assessment Strategies for Vapor Intrusion Passive Samplers and Building Pressure Control

    Science.gov (United States)

    2013-09-01

    Long-Term Monitoring of Soil Vapor Intrusion to Indoor Air Using Quantitative Passive Diffusive- Adsorptive Sampling Techniques,” Mr. Todd McAlary is...on Henry’s Law Constant as >1 × 10-5 atm-m3 mol-1 and a vapor pressure >1 mm Hg Pathway Screening Criteria: For sites with volatile chemicals in...Term Monitoring of Soil Vapor Intrusion to Indoor Air Using Quantitative Passive Diffusive- Adsorptive Sampling Techniques.” The focus of the

  14. Performance Testing of Tracer Gas and Tracer Aerosol Detectors for use in Radionuclide NESHAP Compliance Testing

    Energy Technology Data Exchange (ETDEWEB)

    Fuehne, David Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lattin, Rebecca Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-28

    The Rad-NESHAP program, part of the Air Quality Compliance team of LANL’s Compliance Programs group (EPC-CP), and the Radiation Instrumentation & Calibration team, part of the Radiation Protection Services group (RP-SVS), frequently partner on issues relating to characterizing air flow streams. This memo documents the most recent example of this partnership, involving performance testing of sulfur hexafluoride detectors for use in stack gas mixing tests. Additionally, members of the Rad-NESHAP program performed a functional trending test on a pair of optical particle counters, comparing results from a non-calibrated instrument to a calibrated instrument. Prior to commissioning a new stack sampling system, the ANSI Standard for stack sampling requires that the stack sample location must meet several criteria, including uniformity of tracer gas and aerosol mixing in the air stream. For these mix tests, tracer media (sulfur hexafluoride gas or liquid oil aerosol particles) are injected into the stack air stream and the resulting air concentrations are measured across the plane of the stack at the proposed sampling location. The coefficient of variation of these media concentrations must be under 20% when evaluated over the central 2/3 area of the stack or duct. The instruments which measure these air concentrations must be tested prior to the stack tests in order to ensure their linear response to varying air concentrations of either tracer gas or tracer aerosol. The instruments used in tracer gas and aerosol mix testing cannot be calibrated by the LANL Standards and Calibration Laboratory, so they would normally be sent off-site for factory calibration by the vendor. Operational requirements can prevent formal factory calibration of some instruments after they have been used in hazardous settings, e.g., within a radiological facility with potential airborne contamination. The performance tests described in this document are intended to demonstrate the reliable

  15. How to chase a tracer - combining conventional salt tracer testing and direct push electrical conductivity profiling for enhanced aquifer characterization

    Science.gov (United States)

    Vienken, Thomas; Huber, Emanuel; Kreck, Manuel; Huggenberger, Peter; Dietrich, Peter

    2017-01-01

    Tracer testing is a well-established technique in hydrogeological site characterization. However, certain a priori knowledge of the hydraulic regime is required beforehand to avoid test failure, e.g. miss of tracer. In this study, we propose a novel tracer test concept for the hydraulic characterization of shallow unconsolidated sedimentary deposits when only scarce a priori information on the hydraulic regime is available. Therefore, we combine conventional salt tracer testing with direct push vertical high resolution electrical conductivity logging. The proposed tracer test concept was successfully tested on coarse, braided river deposits of the Tagliamento River, Italy. With limited a priori information available two tracer tests were performed in three days to reliably determine ground water flow direction and velocity allowing on-site decision-making to adaptively install observation wells for reliable breakthrough curve measurements. Furthermore, direct push vertical electrical profiling provided essential information about the plume characteristics with outstanding measurement resolution and efficiency.

  16. Multiwavelength Strontium Vapor Lasers

    Science.gov (United States)

    Soldatov, A. N.; Yudin, N. A.

    2016-08-01

    Based on an analysis of experimental and theoretical works, modern notion on conditions of forming of population density inversion on self-terminating IR transitions of alkali-earth metals is given. It is demonstrated that there is a significant difference in the inversion formation in lasers on self-terminating transitions in the visible and near-IR ranges and lasers on self-terminating transitions of alkali-earth metals lasing IR lines in the mid-IR range. It is shown that in the discharge circuit of lasers on self-terminating metal atom transitions (LSMT) there are processes strengthening the influence of the known mechanism limiting the frequency and energy characteristics (FEC) of radiation caused by the presence of prepulse electron concentration. The mechanism of influence of these processes on FEC of the LSMT and technical methods of their neutralization are considered. The possibility of obtaining average lasing power of ~200 W from one liter volume of the active medium of the strontium vapor laser is demonstrated under conditions of neutralization of these processes.

  17. Archimedes Mass Filter Vaporizer

    Science.gov (United States)

    Putvinski, S.; Agnew, A. F.; Cluggish, B. P.; Ohkawa, T.; Sevier, L.; Umstadter, K. R.; Dresvin, S. V.; Kuteev, B. V.; Feygenson, O. N.; Ivanov, D. V.; Zverev, S. G.; Miroshnikov, I. V.; Egorov, S. M.; Kiesewetter, D. V.; Maliugin, V. I.

    2001-10-01

    Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. Since high-level waste at Hanford has 99.9its radioactivity associated with heavy elements, the Archimedes Filter can effectively decontaminate over three-quarters of that waste. The Filter process involves some preprocessing followed by volatilization and separation by the magnetic and electric fields of the main plasma. This presentation describes the approach to volatilization of the waste oxy-hydroxide mixture by means of a very high heat flux (q > 10 MW/m2). Such a high heat flux is required to ensure congruent evaporation of the complex oxy-hydroxide mixture and is achieved by injection of small droplets of molten waste into an inductively coupled plasma (ICP) torch. This presentation further addresses different issues related to evaporation of the waste including modeling of droplet evaporation, estimates of parameters of plasma torch, and 2D modeling of the plasma. The experimental test bed for oxide vaporization and results of the initial experiments on oxide evaporation in 60 kW ICP torch will also be described.

  18. Hyperpolarized functional magnetic resonance of murine skeletal muscle enabled by multiple tracer-paradigm synchronizations.

    Science.gov (United States)

    Leftin, Avigdor; Roussel, Tangi; Frydman, Lucio

    2014-01-01

    Measuring metabolism's time- and space-dependent responses upon stimulation lies at the core of functional magnetic resonance imaging. While focusing on water's sole resonance, further insight could arise from monitoring the temporal responses arising from the metabolites themselves, in what is known as functional magnetic resonance spectroscopy. Performing these measurements in real time, however, is severely challenged by the short functional timescales and low concentrations of natural metabolites. Dissolution dynamic nuclear polarization is an emerging technique that can potentially alleviate this, as it provides a massive sensitivity enhancement allowing one to probe low-concentration tracers and products in a single-scan. Still, conventional implementations of this hyperpolarization approach are not immediately amenable to the repeated acquisitions needed in real-time functional settings. This work proposes a strategy for functional magnetic resonance of hyperpolarized metabolites that bypasses this limitation, and enables the observation of real-time metabolic changes through the synchronization of stimuli-triggered, multiple-bolus injections of the metabolic tracer 13C1-pyruvate. This new approach is demonstrated with paradigms tailored to reveal in vivo thresholds of murine hind-limb skeletal muscle activation, involving the conversion of 13C1-pyruvate to 13C1-lactate and 13C1-alanine. These functional hind-limb studies revealed that graded skeletal muscle stimulation causes commensurate increases in glycolytic metabolism in a frequency- and amplitude-dependent fashion, that can be monitored on the seconds/minutes timescale using dissolution dynamic nuclear polarization. Spectroscopic imaging further allowed the in vivo visualization of uptake, transformation and distribution of the tracer and products, in fast-twitch glycolytic and in slow-twitch oxidative muscle fiber groups. While these studies open vistas in time and sensitivity for metabolic

  19. Hyperpolarized functional magnetic resonance of murine skeletal muscle enabled by multiple tracer-paradigm synchronizations.

    Directory of Open Access Journals (Sweden)

    Avigdor Leftin

    Full Text Available Measuring metabolism's time- and space-dependent responses upon stimulation lies at the core of functional magnetic resonance imaging. While focusing on water's sole resonance, further insight could arise from monitoring the temporal responses arising from the metabolites themselves, in what is known as functional magnetic resonance spectroscopy. Performing these measurements in real time, however, is severely challenged by the short functional timescales and low concentrations of natural metabolites. Dissolution dynamic nuclear polarization is an emerging technique that can potentially alleviate this, as it provides a massive sensitivity enhancement allowing one to probe low-concentration tracers and products in a single-scan. Still, conventional implementations of this hyperpolarization approach are not immediately amenable to the repeated acquisitions needed in real-time functional settings. This work proposes a strategy for functional magnetic resonance of hyperpolarized metabolites that bypasses this limitation, and enables the observation of real-time metabolic changes through the synchronization of stimuli-triggered, multiple-bolus injections of the metabolic tracer 13C1-pyruvate. This new approach is demonstrated with paradigms tailored to reveal in vivo thresholds of murine hind-limb skeletal muscle activation, involving the conversion of 13C1-pyruvate to 13C1-lactate and 13C1-alanine. These functional hind-limb studies revealed that graded skeletal muscle stimulation causes commensurate increases in glycolytic metabolism in a frequency- and amplitude-dependent fashion, that can be monitored on the seconds/minutes timescale using dissolution dynamic nuclear polarization. Spectroscopic imaging further allowed the in vivo visualization of uptake, transformation and distribution of the tracer and products, in fast-twitch glycolytic and in slow-twitch oxidative muscle fiber groups. While these studies open vistas in time and sensitivity for

  20. Dual-tracer transport experiments in a physically and chemically heterogeneous porous aquifer: effective transport parameters and spatial variability

    Science.gov (United States)

    Ptak, T.; Schmid, G.

    1996-08-01

    In order to investigate the effects of reactive transport processes within a heterogeneous porous aquifer, two small-scale forced gradient tracer tests were conducted at the 'Horkheimer Insel' field site. During the experiments, two fluorescent tracers were injected simultaneously in the same fully penetrating groundwater monitoring well, located approximately 10 m from the pumping well. Fluoresceine and Rhodamine WT were used to represent the classes of practically non-sorbing and sorbing solutes, respectively. Multilevel breakthrough curves with a temporal resolution of 1 min were measured for both tracers at different depths within the pumping well using fibre-optic fluorimeters. This paper presents the tracer test design, the fibre-optic fluorimetry instrumentation, the experimental results and the interpretation of the measured multilevel breakthrough curves in terms of temporal moments and effective transport parameters. Significant sorption of Rhodamine WT is apparent from the effective retardation factors. Furthermore, an enhanced tailing of Rhodamine WT breakthrough curves is observed, which is possibly caused by a variability of aquifer sorption properties. The determined effective parameters are spatially variable, suggesting that a complex numerical flow and transport modelling approach within a stochastic framework will be needed to adequately describe the transport behaviour observed in the two experiments. Therefore, the tracer test results will serve in future work for the validation of numerical stochastic transport simulations taking into account the spatial variability of hydraulic conductivity and sorption-related aquifer properties.

  1. On the linearity of tracer bias around voids

    Science.gov (United States)

    Pollina, Giorgia; Hamaus, Nico; Dolag, Klaus; Weller, Jochen; Baldi, Marco; Moscardini, Lauro

    2017-07-01

    The large-scale structure of the Universe can be observed only via luminous tracers of the dark matter. However, the clustering statistics of tracers are biased and depend on various properties, such as their host-halo mass and assembly history. On very large scales, this tracer bias results in a constant offset in the clustering amplitude, known as linear bias. Towards smaller non-linear scales, this is no longer the case and tracer bias becomes a complicated function of scale and time. We focus on tracer bias centred on cosmic voids, i.e. depressions of the density field that spatially dominate the Universe. We consider three types of tracers: galaxies, galaxy clusters and active galactic nuclei, extracted from the hydrodynamical simulation Magneticum Pathfinder. In contrast to common clustering statistics that focus on auto-correlations of tracers, we find that void-tracer cross-correlations are successfully described by a linear bias relation. The tracer-density profile of voids can thus be related to their matter-density profile by a single number. We show that it coincides with the linear tracer bias extracted from the large-scale auto-correlation function and expectations from theory, if sufficiently large voids are considered. For smaller voids we observe a shift towards higher values. This has important consequences on cosmological parameter inference, as the problem of unknown tracer bias is alleviated up to a constant number. The smallest scales in existing data sets become accessible to simpler models, providing numerous modes of the density field that have been disregarded so far, but may help to further reduce statistical errors in constraining cosmology.

  2. Vapor Intrusion Facilities - South Bay

    Data.gov (United States)

    U.S. Environmental Protection Agency — POINT locations for the South Bay Vapor Instrusion Sites were derived from the NPL data for Region 9. One site, Philips Semiconductor, was extracted from the...

  3. Understanding Latent Heat of Vaporization.

    Science.gov (United States)

    Linz, Ed

    1995-01-01

    Presents a simple exercise for students to do in the kitchen at home to determine the latent heat of vaporization of water using typical household materials. Designed to stress understanding by sacrificing precision for simplicity. (JRH)

  4. Modeling vapor dominated geothermal reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Marconcini, R.; McEdwards, D.; Neri, G.; Ruffilli, C.; Schroeder, R.; Weres, O.; Witherspoon, P.

    1977-09-12

    The unresolved questions with regard to vapor-dominated reservoir production and longevity are reviewed. The simulation of reservoir behavior and the LBL computer program are discussed. The geology of Serrazzano geothermal field and its reservoir simulation are described. (MHR)

  5. Water injection into vapor- and liquid-dominated reservoirs: Modeling of heat transfer and mass transport

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, K.; Oldenburg, C.; Moridis, G.; Finsterle, S. [Lawrence Berkeley National Lab., CA (United States)

    1997-12-31

    This paper summarizes recent advances in methods for simulating water and tracer injection, and presents illustrative applications to liquid- and vapor-dominated geothermal reservoirs. High-resolution simulations of water injection into heterogeneous, vertical fractures in superheated vapor zones were performed. Injected water was found to move in dendritic patterns, and to experience stronger lateral flow effects than predicted from homogeneous medium models. Higher-order differencing methods were applied to modeling water and tracer injection into liquid-dominated systems. Conventional upstream weighting techniques were shown to be adequate for predicting the migration of thermal fronts, while higher-order methods give far better accuracy for tracer transport. A new fluid property module for the TOUGH2 simulator is described which allows a more accurate description of geofluids, and includes mineral dissolution and precipitation effects with associated porosity and permeability change. Comparisons between numerical simulation predictions and data for laboratory and field injection experiments are summarized. Enhanced simulation capabilities include a new linear solver package for TOUGH2, and inverse modeling techniques for automatic history matching and optimization.

  6. A field test of tracer transport and organic contaminant elution in a stratified aquifer at the Rocky Mountain Arsenal (Denver, Colorado, U.S.A.)

    Science.gov (United States)

    Thorbjarnarson, Kathryn W.; Mackay, Douglas M.

    1997-01-01

    A tracer-elution experiment was conducted in a 9-m-thick alluvial sand aquifer at the Rocky Mountain Arsenal, Denver, Colorado, within an extensive 1,1,1-trichloroethene and trichloroethene plume. The forced-gradient flow field was controlled by an injection well and an extraction well separated by 8.4 m and aligned in the direction of the natural-gradient flow. Upon extraction, the contaminant-laden water was treated by air stripping and reinjected into the injection well. Iodide tracer was added to the injection flow during the initial 27.5 h of the experiment. Tracer transport and organic contaminant elution were monitored by four 0.15-m-screened drive points and a fully penetrating monitoring well. Relative permeabilities, dispersivities and retardation factors were estimated from tracer breakthrough and contaminant elution curves by the moment method and by curve-fitting with an advection-dispersion model. Tracer transport through the four strata sampled by the drive points indicated a permeability variation of three orders of magnitude. Contaminant elution was not observed in the lowest-permeability stratum monitored during the experiment. In all monitored strata, contaminant elution was controlled primarily by permeability effects on water flow and exhibited minimal retardation or desorption effects. The fully penetrating monitoring well exhibited a tracer response primarily from the more permeable strata with the addition of tracer from the less permeable strata producing an increased breakthrough spreading. This increased spreading or dispersion was reflected in a higher longitudinal dispersivity estimate (1.2 m assuming a homogeneous aquifer) than dispersivity estimates from the drive-point sampler tracer curves (ranging from 5 to 21 cm). Contaminant elution curves from the fully penetrating monitoring well exhibited an initial response primarily from the more permeable strata (rapid elution of contaminants) and provided no insight into the elution

  7. Star clusters as tracers of galaxy evolution

    CERN Document Server

    Konstantopoulos, Iraklis S

    2009-01-01

    Star clusters represent the most common 'mode' of star formation. They are found in all types of environments, cascading down from galaxy groups and merging pairs through starbursts to normal galaxies and dwarves and even isolated regions in extragalactic space. As they maintain a link to the overall star formation in a system, they can be used as tracers of the star formation history of environments located at distances prohibitive to the study of individual stars. This makes them ideally suited to the study of mergers and interactions in galaxy pairs and groups. In this work we present observations of the star cluster populations in the local starburst galaxy M82, post-interaction spiral NGC 6872, the "Antennae" merging pair and two compact groups, "Stephan's Quintet" and HCG 7. In each case, we extract information on the clusters and their hosts using mainly HST photometry and Gemini spectroscopy.

  8. Elemental tracers for Chinese source dust

    Institute of Scientific and Technical Information of China (English)

    张小曳; 张光宇; 朱光华; 张德二; 安芷生; 陈拓; 黄湘萍

    1996-01-01

    The mass-particle size distributions of 10 dust-carrying elements in aerosol particles were determined tor 12 sites in desert regions of northern China. The desert dust is proved to he of origin of eolian loess deposited on the Loess Plateau. Their transport to the loess was mainly attributable to the non-dust storm processes under the interglacial climate condition. The impact ot" dust storm on the accumulation of the loess increased in the glacial stage. On the basis of the signatures of 4 dust elements (Al. Fe, Mg and Sc). Chinese dust is believed to have 3 major desert sources (northwestern deserts, northern high dust deserts and northern low dust deserts). With a chemical element balance model, an elemental tracer system is established to proportion the export of China-source dust.

  9. Tracer studies of nitrogen assimilation in yeast.

    Science.gov (United States)

    ABRAMS, R; HAMMARSTEN, E

    1949-01-01

    By using N(15) as a tracer the assimilation of ammonia by the yeast, Torulopsis utilis, has been studied. It has been shown that: 1. There was no measurable incorporation of N in the protein or polynucleotide purine of carbon-starved yeast. 2. When ammonia is added to nitrogen-starved yeast there is a long lag period before division begins during which the yeast rapidly synthesizes protein, this process being accompanied by a turnover of polynucleotide purine. There was no significant dilution of the N(15)H(4) (+) of the medium by ordinary NH(4) (+). 3. When yeast containing N(15) is allowed to divide and grow in ordinary ammonia, the total amount of N(15) in the yeast remains constant. The dicarboxylic amino acids are most diluted, while arginine and nucleic acid guanine are not diluted at all.

  10. National Biomedical Tracer Facility. Project definition study

    Energy Technology Data Exchange (ETDEWEB)

    Schafer, R.

    1995-02-14

    We request a $25 million government-guaranteed, interest-free loan to be repaid over a 30-year period for construction and initial operations of a cyclotron-based National Biomedical Tracer Facility (NBTF) in North Central Texas. The NBTF will be co-located with a linear accelerator-based commercial radioisotope production facility, funded by the private sector at approximately $28 million. In addition, research radioisotope production by the NBTF will be coordinated through an association with an existing U.S. nuclear reactor center that will produce research and commercial radioisotopes through neutron reactions. The combined facilities will provide the full range of technology for radioisotope production and research: fast neutrons, thermal neutrons, and particle beams (H{sup -}, H{sup +}, and D{sup +}). The proposed NBTF facility includes an 80 MeV, 1 mA H{sup -} cyclotron that will produce proton-induced (neutron deficient) research isotopes.

  11. Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers

    Science.gov (United States)

    Matthews, James C.; Bacak, Asan; Khan, M. Anwar H.; Wright, Matthew D.; Priestley, Michael; Martin, Damien; Percival, Carl J.; Shallcross, Dudley E.

    2017-01-01

    People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO2 tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants. PMID:28230812

  12. Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers.

    Science.gov (United States)

    Matthews, James C; Bacak, Asan; Khan, M Anwar H; Wright, Matthew D; Priestley, Michael; Martin, Damien; Percival, Carl J; Shallcross, Dudley E

    2017-02-21

    People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO₂ tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants.

  13. On the linearity of tracer bias around voids

    CERN Document Server

    Pollina, Giorgia; Dolag, Klaus; Weller, Jochen; Baldi, Marco; Moscardini, Lauro

    2016-01-01

    The large-scale structure of the universe can only be observed directly via luminous tracers of the underlying distribution of dark matter. However, the clustering statistics of tracers are biased and depend on various properties of the tracers themselves, such as their host-halo mass and formation and assembly history. On very large scales, where density fluctuations are within the linear regime, this tracer bias results in a constant offset in the clustering amplitude, which is known as linear bias. Towards smaller non-linear scales, this is no longer the case and tracer bias becomes a complicated function of scale and time. We focus on tracer bias centered on cosmic voids, depressions of the density field that spatially dominate the universe. We consider three different types of tracers: galaxies, galaxy clusters and AGNs, extracted from the hydrodynamical simulation suite Magneticum Pathfinder. In contrast to common clustering statistics that focus on the auto-correlation of tracers, we find that void-tra...

  14. Dispensing fuel with aspiration of condensed vapors

    Energy Technology Data Exchange (ETDEWEB)

    Butkovich, M.S.; Strock, D.J.

    1993-08-10

    A vapor recovery process is described, comprising the steps of: fueling a motor vehicle with gasoline by discharging gasoline into a fill opening or filler pipe of a tank of said vehicle through a fuel outlet conduit of a nozzle; emitting gasoline vapors from said tank during said fueling; substantially collecting said vapors during said fueling with a vapor return conduit of said nozzle and passing said vapors through said vapor return conduit in counter current flow relationship to said discharging gasoline in said fuel conduit; conveying said vapors from said vapor return conduit to a vapor return hose; at least some of said vapors condensing to form condensate in said vapor return hose; substantially removing said condensate from said vapor return hose during said fueling with a condensate pickup tube from said nozzle by passing said condensate through said condensate pickup tube in counter current flow relationship to said conveying vapors in said vapor return hose; sensing the presence of gasoline with a liquid sensing tube in said vapor return conduit of said nozzle between inner and outer spouts of said nozzle to detect when said tank of said vehicle is filled with said fuel conduit being within the inner spout of said nozzle; and automatically shutting off said fueling and condensate removing when said liquid sensing tube detects when said tank of said vehicle is filled and fuel enters said vapor return conduit.

  15. The Persistence of Potential Refugia Mapped from Gravel Tracers

    Science.gov (United States)

    Haschenburger, J. K.

    2009-12-01

    Floods disturb aquatic habitats. On an event basis, flood characteristics control the spatial extent and depth of streambed disturbance for a given river and set limits to the amount of channel refugia for biota. The aim of this research is to quantify the area of potential refugia that persists over a long flood series and therefore affects many generations of aquatic populations. Field observations were collected in Carnation Creek, a small gravel-bed river located on the west coast of Vancouver Island, Canada. Streambed disturbance was documented by monitoring the three-dimensional positions of about 2500 magnetically tagged gravels over 277 floods. Tracer movement and burial observations were used to produce cellular maps of the frequency of bed disturbance within a GIS. The streambed exhibits different frequencies of disturbance as expected. The most active areas make up about 1% of the streambed and tend to be located near the channel thalweg. Undisturbed areas constitute more than 25% of the bed, and provide distinct areas of longer-term refugia that persist over the range of flood magnitudes observed. In addition to validating a key aspect of partial sediment transport, the results suggest that the natural variability of floods facilitates diverse aquatic communities by ensuring the availability of channel refugia over time.

  16. TPR system: a powerful technique to monitor carbon nanotube formation during chemical vapour deposition; Sistema RTP: uma tecnica poderosa para o monitoramento da formacao de nanotubos de carbono durante o processo por deposicao de vapor quimico

    Energy Technology Data Exchange (ETDEWEB)

    Tristao, Juliana Cristina; Moura, Flavia Cristina Camilo; Lago, Rochel Montero, E-mail: rochel@ufmg.b [Universidade Federal de Minas Gerais (DQ/UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Sapag, Karim [Universidade Nacional de San Luis (Argentina). Lab. de Ciencias de Superficies y Medios Porosos

    2010-07-01

    In this work, a TPR (Temperature Programmed Reduction) system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition), The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al{sub 2}O{sub 3} and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields. (author)

  17. In-situ observations of water vapor isotopes in near surface air over Lakes Superior and Michigan

    Science.gov (United States)

    Welp, L.; Meyer, A. L.; Griffis, T. J.

    2016-12-01

    The Laurentian Great Lakes play an important role in the climate of the midwestern to northeastern United States. Evaporation from the lakes is not well quantified, and the factors controlling lake evaporation are not fully understood. Two isotopic tracer methods have been used to study lake evaporation. The first is a lake water isotopic mass balance to solve for evaporation rates from precipitation and runoff inputs and the residual lake water. The second method is monitoring downwind precipitation and atmospheric water vapor for evidence of lake evaporation. Accurate estimates of the isotopic composition of evaporation from the lakes are critical inputs in both methods for modern and paleo studies. Traditionally, evaporation is assumed to follow the Craig-Gordon model of isotopic fractionation. To our knowledge, this model has not been tested on large lakes like the Great Lakes, whose evaporation flux strongly influences the moisture in the air above the lake. To test the Craig-Gordon model, we made measurements of the hydrogen and oxygen isotope ratios above the surface of Lakes Superior and Michigan during June 2016 during a 4-day cruise on the R/V Blue Heron research vessel that traveled from Duluth, MN to Milwaukee, WI. Air was sampled at 2 intakes, approximately 5 m and 15 m above the lake surface, using an LGR triple water vapor isotope analyzer. The isotopic composition of lake water became more enriched in the heavy isotopes from Lake Superior to Lake Michigan. The timing of these measurements in late spring is not an optimal time to observe evaporation off the lakes, because often the lake temperature is cooler than the air temperature, thereby suppressing the evaporation flux. At times, vertical gradients of water vapor mixing in the near surface air approached 2,000-3,000 ppm, with higher moisture at the lower intake than the upper intake. At night, we observed times when this gradient reversed, and there was higher moisture aloft compared to the

  18. Developement of radioisotope tracer technique; development of verification method for hydraulic model using radioisotope tracer techniques in the municipal wastewater treatment plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C. W.; Kim, S. H.; Kim, J. W.; Yun, J. S.; Wo, S. B. [Pusan National University, Pusan (Korea)

    2001-04-01

    This study focuses on the development of the computational fluid dynamics that can be used in secondary clarifier in wastewater treatment plants. This model could describe the internal flow characteristics and predicted similar results as the isotopic tracer experiment. Therefore, it was demonstrated that the isotopic tracer method was a powerful tool as a hydrodynamic model to understand the internal hydraulics. Generally the secondary clarifier can be improved by special design, changing coagulation characteristics by addition of coagulation chemicals and well management by experienced operator. Because of expensive coagulation chemicals and limited availability of experienced operator, the improvement of the design is feasible way to upgrade the secondary clarifier. Though it is very complex and difficult to model the fluid dynamics, CFD model can describe correctly density flow, short circuiting, turbulent dispersion and settling characteristics. There are few trust worthy methods for verifying the hydrodynamic model. Also, it is very difficult to prove the flow by experiment in secondary sedimentation tank because of the disturbing the flow by the experimental equipment. However, the isotope tracer experiment is known as a useful tool for the study of the hydraulic characteristics and floc movement in the sedimentation tank because the isotope tracer does not disturb the internal flow and provide the data quickly through the on-line system. Therefore, the computed fluid dynamic model was developed to make the isotope tracer experiment available as a model verifying method. Predicted results in model simulation were made the same pattern as the experiment on-line data with the time. These results were compared each other. Also, the model explained the detail flow pattern of the area without the monitoring in the sedimentation tank and visualized the internal flow and concentration distribution with time using the graphic software. Because of the complicated

  19. Developement of radioisotope tracer technique; development of verification method for hydraulic model using radioisotope tracer techniques in the municipal wastewater treatment plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C. W.; Kim, S. H.; Kim, J. W.; Yun, J. S.; Wo, S. B. [Pusan National University, Pusan (Korea)

    2001-04-01

    This study focuses on the development of the computational fluid dynamics that can be used in secondary clarifier in wastewater treatment plants. This model could describe the internal flow characteristics and predicted similar results as the isotopic tracer experiment. Therefore, it was demonstrated that the isotopic tracer method was a powerful tool as a hydrodynamic model to understand the internal hydraulics. Generally the secondary clarifier can be improved by special design, changing coagulation characteristics by addition of coagulation chemicals and well management by experienced operator. Because of expensive coagulation chemicals and limited availability of experienced operator, the improvement of the design is feasible way to upgrade the secondary clarifier. Though it is very complex and difficult to model the fluid dynamics, CFD model can describe correctly density flow, short circuiting, turbulent dispersion and settling characteristics. There are few trust worthy methods for verifying the hydrodynamic model. Also, it is very difficult to prove the flow by experiment in secondary sedimentation tank because of the disturbing the flow by the experimental equipment. However, the isotope tracer experiment is known as a useful tool for the study of the hydraulic characteristics and floc movement in the sedimentation tank because the isotope tracer does not disturb the internal flow and provide the data quickly through the on-line system. Therefore, the computed fluid dynamic model was developed to make the isotope tracer experiment available as a model verifying method. Predicted results in model simulation were made the same pattern as the experiment on-line data with the time. These results were compared each other. Also, the model explained the detail flow pattern of the area without the monitoring in the sedimentation tank and visualized the internal flow and concentration distribution with time using the graphic software. Because of the complicated

  20. Characterization of an alluvial aquifer with thermal tracer tomography

    Science.gov (United States)

    Somogyvári, Márk; Bayer, Peter

    2017-04-01

    In the summer of 2015, a series of thermal tracer tests was performed at the Widen field site in northeast Switzerland. At this site numerous hydraulic, tracer, geophysical and hydrogeophysical field tests have been conducted in the past to investigate a shallow alluvial aquifer. The goals of the campaign in 2015 were to design a cost-effective thermal tracer tomography setup and to validate the concept of travel time-based thermal tracer tomography under field conditions. Thermal tracer tomography uses repeated thermal tracer injections with different injection depths and distributed temperature measurements to map the hydraulic conductivity distribution of a heterogeneous aquifer. The tracer application was designed with minimal experimental time and cost. Water was heated in inflatable swimming pools using direct sunlight of the warm summer days, and it was injected as low temperature pulses in a well. Because of the small amount of injected heat, no long recovery times were required between the repeated heat tracer injections and every test started from natural thermal conditions. At Widen, four thermal tracer tests were performed during a period of three days. Temperatures were measured in one downgradient well using a distributed temperature measurement system installed at seven depth points. Totally 12 temperature breakthrough curves were collected. Travel time based tomographic inversion assumes that thermal transport is dominated by advection and the travel time of the thermal tracer can be related to the hydraulic conductivities of the aquifer. This assumption is valid in many shallow porous aquifers where the groundwater flow is fast. In our application, the travel time problem was treated by a tomographic solver, analogous to seismic tomography, to derive the hydraulic conductivity distribution. At the test site, a two-dimensional cross-well hydraulic conductivity profile was reconstructed with the travel time based inversion. The reconstructed profile

  1. Water vapor estimation using digital terrestrial broadcasting waves

    Science.gov (United States)

    Kawamura, S.; Ohta, H.; Hanado, H.; Yamamoto, M. K.; Shiga, N.; Kido, K.; Yasuda, S.; Goto, T.; Ichikawa, R.; Amagai, J.; Imamura, K.; Fujieda, M.; Iwai, H.; Sugitani, S.; Iguchi, T.

    2017-03-01

    A method of estimating water vapor (propagation delay due to water vapor) using digital terrestrial broadcasting waves is proposed. Our target is to improve the accuracy of numerical weather forecast for severe weather phenomena such as localized heavy rainstorms in urban areas through data assimilation. In this method, we estimate water vapor near a ground surface from the propagation delay of digital terrestrial broadcasting waves. A real-time delay measurement system with a software-defined radio technique is developed and tested. The data obtained using digital terrestrial broadcasting waves show good agreement with those obtained by ground-based meteorological observation. The main features of this observation are, no need for transmitters (receiving only), applicable wherever digital terrestrial broadcasting is available and its high time resolution. This study shows a possibility to estimate water vapor using digital terrestrial broadcasting waves. In the future, we will investigate the impact of these data toward numerical weather forecast through data assimilation. Developing a system that monitors water vapor near the ground surface with time and space resolutions of 30 s and several kilometers would improve the accuracy of the numerical weather forecast of localized severe weather phenomena.

  2. A Review of Vapor Intrusion Models

    OpenAIRE

    Yao, Yijun; Suuberg, Eric M.

    2013-01-01

    A complete vapor intrusion (VI) model, describing vapor entry of volatile organic chemicals (VOCs) into buildings located on contaminated sites, generally consists of two main parts-one describing vapor transport in the soil and the other its entry into the building. Modeling the soil vapor transport part involves either analytically or numerically solving the equations of vapor advection and diffusion in the subsurface. Contaminant biodegradation must often also be included in this simulatio...

  3. Recent advances in vapor intrusion site investigations.

    Science.gov (United States)

    McHugh, Thomas; Loll, Per; Eklund, Bart

    2017-02-22

    Our understanding of vapor intrusion has evolved rapidly since the discovery of the first high profile vapor intrusion sites in the late 1990s and early 2000s. Research efforts and field investigations have improved our understanding of vapor intrusion processes including the role of preferential pathways and natural barriers to vapor intrusion. This review paper addresses recent developments in the regulatory framework and conceptual model for vapor intrusion. In addition, a number of innovative investigation methods are discussed.

  4. Methods and systems using encapsulated tracers and chemicals for reservoir interrogation and manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Jeffery; Aines, Roger D; Duoss, Eric B; Spadaccini, Christopher M

    2014-11-04

    An apparatus, method, and system of reservoir interrogation. A tracer is encapsulating in a receptacle. The receptacle containing the tracer is injected into the reservoir. The tracer is analyzed for reservoir interrogation.

  5. Investigation of Groundwater Flow Variations near a Recharge Pond with Repeat Deliberate Tracer Experiments

    Directory of Open Access Journals (Sweden)

    Jordan F Clark

    2014-06-01

    Full Text Available Determining hydraulic connections and travel times between recharge facilities and production wells has become increasingly important for permitting and operating managed aquifer recharge (MAR sites, a water supply strategy that transfers surface water into aquifers for storage and later extraction. This knowledge is critical for examining water quality changes and assessing the potential for future contamination. Deliberate tracer experiments are the best method for determining travel times and identifying preferential flow paths between recharge sites over the time scales of weeks to a few years. This paper compares the results of two deliberate tracer experiments at Kraemer Basin, Orange County, CA, USA. Results from the first experiment, which was conducted in October 1998, showed that a region of highly transmissive sedimentary material extends down gradient from the basin for more than 3 km [1]. Mean groundwater velocities were determined to be approximately 2 km/year in this region based on the arrival time of the tracer center of mass. A second experiment was initiated in January 2008 to determine if travel times from this basin to monitoring and production wells changed during the past decade in response to new recharge conditions. Results indicate that flow near Kraemer Basin was stable, and travel times to most wells determined during both experiments agree within the experimental uncertainty.

  6. Multi Resolution AHB Bus Tracer with Real Time Compression for SOC

    Directory of Open Access Journals (Sweden)

    J. Jagadish Reddy

    2013-01-01

    Full Text Available AMBA (Advanced Microcontroller based Bus Architecture consists of AHB, APB, ASB and AXI. In this project we are Tracing AHB (Advanced High performance Bus signals with Real time Compression and Multi-resolution Techniques. A simple transaction on the AHB consists of an address phase and a subsequent data phase. Access to the target device is controlled through a MUX , thereby admitting bus-access to one bus-master at a time. In AHB Tracer we have to Trace Address signals, Data signals and Control signals, we have to compress them depending on AHB protocols. A multi-resolution AHB on-chip bus tracer is named as SYS_HMRBT (AHB Multi-resolution Bus Tracer and is used for monitoring. The goal is to provide better compression quality and multiple resolution traces to meet the complex SoC debugging needs. Compressing all signals at cycle-accurate-level does not always meet the debugging needs. As SOCs become more complex, the transaction level debugging becomes increasingly important, since it helps designers focus on the functional behaviors, instead of interpreting complex signals. By using this SYS_HMRBT, we can achieve 79%-96% of compression depending on selected resolution mode. Tools Used for this Project are Modelsim for Simulation, and Xilinx ISE II for Synthesis

  7. Use of rare earth oxides as tracers to identify sediment source areas for agricultural hillslopes

    Directory of Open Access Journals (Sweden)

    C. Deasy

    2010-11-01

    Full Text Available Understanding sediment sources is essential to enable more effective targeting of in-field mitigation approaches to reduce diffuse pollution from agricultural land. In this paper we report on the application of rare earth element oxides to arable soils at hillslope scale in order to determine sediment source areas and their relative importance, using a non-intrusive method of surface spraying. Runoff, sediments and rare earth elements lost from four arable hillslope lengths at a site in the UK with clay soils were monitored from three rainfall events after tracer application. Measured erosion rates were low, reflecting the typical event conditions occurring at the site, and less than 1% of the applied REO tracers were recovered, which is consistent with the results of comparable studies. Tracer recovery at the base of the hillslope was able to indicate the relative importance of different hillslope sediment source areas, which were found to be consistent between events. The principal source of eroded sediments was the upslope area, implying that the wheel tracks were principally conduits for sediment transport, and not highly active sites of erosion. Mitigation treatments for sediment losses from arable hillslopes should therefore focus on methodologies for trapping mobile sediments within wheel track areas through increasing surface roughness or reducing the connectivity of sediment transport processes.

  8. Use of rare earth oxides as tracers to identify sediment source areas for agricultural hillslopes

    Directory of Open Access Journals (Sweden)

    C. Deasy

    2010-07-01

    Full Text Available Understanding sediment sources is essential to enable more effective targeting of in-field mitigation approaches to reduce diffuse pollution from agricultural land. In this paper we report on the application of rare earth element oxides to arable soils at hillslope scale in order to determine sediment source areas and their relative importance, using a non-intrusive method of surface spraying. Runoff, sediments and rare earth elements lost from four arable hillslope lengths at a site in the UK with clay soils were monitored from three rainfall events after tracer application. Measured erosion rates were low, reflecting the typical event conditions occurring at the site, and less than 1% of the applied REO tracers were recovered, which is consistent with the results of comparable studies. Tracer recovery at the base of the hillslope was able to indicate the relative importance of different hillslope sediment source areas, which were found to be consistent between events. The principal source of eroded sediments was the upslope area, implying that the wheel tracks were principally conduits for sediment transport, and not highly active sites of erosion. Mitigation treatments for sediment losses from arable hillslopes should therefore focus on methodologies for trapping mobile sediments within wheel track areas through increasing surface roughness or reducing the connectivity of sediment transport processes.

  9. Use of rare earth oxides as tracers to identify sediment source areas for agricultural hillslopes

    Science.gov (United States)

    Deasy, C.; Quinton, J. N.

    2010-11-01

    Understanding sediment sources is essential to enable more effective targeting of in-field mitigation approaches to reduce diffuse pollution from agricultural land. In this paper we report on the application of rare earth element oxides to arable soils at hillslope scale in order to determine sediment source areas and their relative importance, using a non-intrusive method of surface spraying. Runoff, sediments and rare earth elements lost from four arable hillslope lengths at a site in the UK with clay soils were monitored from three rainfall events after tracer application. Measured erosion rates were low, reflecting the typical event conditions occurring at the site, and less than 1% of the applied REO tracers were recovered, which is consistent with the results of comparable studies. Tracer recovery at the base of the hillslope was able to indicate the relative importance of different hillslope sediment source areas, which were found to be consistent between events. The principal source of eroded sediments was the upslope area, implying that the wheel tracks were principally conduits for sediment transport, and not highly active sites of erosion. Mitigation treatments for sediment losses from arable hillslopes should therefore focus on methodologies for trapping mobile sediments within wheel track areas through increasing surface roughness or reducing the connectivity of sediment transport processes.

  10. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    Science.gov (United States)

    Gorski, Galen; Strong, Courtenay; Good, Stephen P.; Bares, Ryan; Ehleringer, James R.; Bowen, Gabriel J.

    2015-01-01

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry. PMID:25733906

  11. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    Science.gov (United States)

    Gorski, Galen; Strong, Courtenay; Good, Stephen P.; Bares, Ryan; Ehleringer, James R.; Bowen, Gabriel J.

    2015-03-01

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.

  12. Standard hydrogen monitoring system equipment installation instructions

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, T.C.

    1996-09-27

    This document provides the technical specifications for the equipment fabrication, installation, and sitework construction for the Standard Hydrogen Monitoring System. The Standard Hydrogen Monitoring System is designed to remove gases from waste tank vapor space and exhaust headers for continual monitoring and remote sample analysis.

  13. Heat Transfer Characterization Using Heat and Solute Tracer Tests in a Shallow Alluvial Aquifer

    Science.gov (United States)

    Dassargues, A.

    2013-12-01

    Very low enthalpy geothermal systems are increasingly considered for heating or cooling using groundwater energy combined with heat pumps. The design and the impact of shallow geothermal systems are often assessed in a semi-empirical way. It is accepted by most of the private partners but not by environmental authorities deploring a lack of rigorous evaluation of the mid- to long-term impact on groundwater. In view of a more rigorous methodology, heat and dye tracers are used for estimating simultaneously heat transfer and solute transport parameters in an alluvial aquifer. The experimental field site, is equipped with 21 piezometers drilled in alluvial deposits composed of a loam layer overlying a sand and gravel layer constituting the alluvial aquifer. The tracing experiment consisted in injecting simultaneously heated water and a dye tracer in a piezometer and monitoring evolution of groundwater temperature and tracer concentration in 3 control panels set perpendicularly to the main groundwater flow. Results showed drastic differences between heat transfer and solute transport due to the main influence of thermal capacity of the saturated porous medium. The tracing experiment was then simulated using a numerical model and the best estimation of heat transfer and solute transport parameters is obtained by calibrating this numerical model using inversion tools. The developed concepts and tests may lead to real projects of various extents that can be now optimized by the use of a rigorous and efficient methodology at the field scale. On the field: view from the injection well in direction of the pumping well through the three monitoring panels Temperature monitoring in the pumping well and in the piezometers of the three panels: heat transfer is faster in the lower part of the aquifer (blue curves) than in the upper part (red curves). Breakthrough curves are also more dispersed in the upper part with longer tailings.

  14. Water Vapor Products from Differential-InSAR with Auxiliary Calibration Data: Accuracy and Statistics

    Science.gov (United States)

    Gong, W.; Meyer, F. J.; Webley, P.

    2014-12-01

    Although water vapor disturbance has been long term recognized as the major error source in differential Interferometric Synthetic Aperture Radar (d-InSAR) techniques for the ground deformation monitoring and topography reconstruction, it provides opportunities to extract the atmospheric water-vapor information from satellite SAR imageries that can be further used to support studies on earth energy budget, climate, the hydrological cycle, and meteorological forecasting, etc. The water vapor contribution in interferometric phases is normally referred as the atmospheric delay dominated by water vapor rather than condensed water (e.g. cloud). D-InSAR can produce maps of the column water vapor amounts (equivalent to integrated water vapor (IWV) or Precipitable Water Vapor (PWV) in other literatures) that are important parameters quantitatively describe the total amount of water vapor overlying a point on the earth surface. Similar products have been operationally produced in multi-spectrum remote sensing, e.g. Moderate-resolution Imaging Spectroradiometer (MODIS) with a spatial resolution in 500 m to 1km; Whereas, the PWV products derived by d-InSAR have remarkably high spatial resolution that can capture fine scale of water vapor variations in space as small as tens of meters or even less. In recent years, some efforts have been made to derive the water vapor products from interferogram and analyze the corresponding products quality, such as studies comparing integrated water vapor derived from interferometric phases to other measurements (e.g. MERIS, MODIS, GNSS), studies on deriving absolute water vapor products from d-InSAR, and studies on integrating d-InSAR water vapor products in meteorological numerical forecast. In this study, considering these limitation factors and based on previous studies, we discuss the accuracy and statistics of the water vapor products from satellite SAR, including (1) Accuracy of the differential water vapor products; (2) Sources of

  15. Stage 2 vapor recovery system

    Energy Technology Data Exchange (ETDEWEB)

    Koch, W.H.; Strock, D.J.; Butkovich, M.S.; Hartman, H.B.

    1993-05-25

    A vapor recovery system is described, comprising: a set of elongated underground storage tanks, each storage tank containing a different grade of gasoline; vent pipes; a series of dispensing units; fuel flow lines; vapor return lines; an array of fuel pumps for pumping gasoline from said storage tanks to said dispenser units; an elongated condensate liquid pickup tube; an elongated inner spout providing a fuel conduit and having an outer tip defining a fuel outlet for discharging gasoline into a filler pipe of a motor vehicle tank during fueling; an outer spout assembly; extending into and engaging said spout-receiving socket, said outer spout assembly comprising an outer spout providing a vapor return conduit and defining apertures providing a vapor inlet spaced from said fuel outlet for withdrawing, removing, and returning a substantial amount of gasoline vapors emitted during said fueling; an elongated liquid sensing tube; a manually operable level; a flow control valve assembly; an automatic shutoff valve assembly; and a venturi sleeve assembly positioned in said venturi sleeve receiving chamber.

  16. The Lithium Vapor Box Divertor

    Science.gov (United States)

    Goldston, Robert; Hakim, Ammar; Hammett, Gregory; Jaworski, Michael; Myers, Rachel; Schwartz, Jacob

    2015-11-01

    Projections of scrape-off layer width to a demonstration power plant suggest an immense parallel heat flux, of order 12 GW/m2, which will necessitate nearly fully detached operation. Building on earlier work by Nagayama et al. and by Ono et al., we propose to use a series of differentially pumped boxes filled with lithium vapor to isolate the buffering vapor from the main plasma chamber, allowing stable detachment. This powerful differential pumping is only available for condensable vapors, not conventional gases. We demonstrate the properties of such a system through conservation laws for vapor mass and enthalpy, and then include plasma entrainment and ultimately an estimate of radiated power. We find that full detachment should be achievable with little leakage of lithium to the main plasma chamber. We also present progress towards solving the Navier-Stokes equation numerically for the chain of vapor boxes, including self-consistent wall boundary conditions and fully-developed shocks, as well as concepts for an initial experimental demonstration-of-concept. This work supported by DOE Contract No. DE-AC02-09CH11466.

  17. Results of an injection test using ethyl alcohol as tracer at Los Humeros geothermal field, Puebla, Mexico; Resultados de una prueba de inyeccion de alcohol empleado como trazador, en el campo geotermico de Los humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Tovar Aguado, Rigoberto; Lopez Romero, Oscar [Comision Federal de Electricidad, Los Humeros, Puebla (Mexico)

    2000-12-01

    Los Humeros is the third Mexican geothermal field where ethyl alcohol was used as organic tracer to test communication between wells. The first Mexican geothermal field where this kind of test was used Los Azufres, Michoacan. The second was Las Tres Virgenes, Baja California Sur. In both cases, connections between wells were observed. The injection well H-29 is in the north-central sector of Los Humeros geothermal field, Puebla, Mexico. At a depth of 1580 meters, 600 liters of ethyl alcohol was pumped through a 60.35 mm (23/8 inch) diameter tube after 2.7 m{sup 3} of geothermal fluids were displaced, allowing the alcohol to reach the formation. Then, the normal injection process continued with water and condensed steam (130 t/h). On the basis of the experience acquired with similar tests conducted at Las Tres Virgenes geothermal field, and with the goal of detecting the tracer, samples of condensed steam were collected in nearby wells (H-15, H-16, H-17, H-30, H-33, H-36 and H-8) and in distant wells-named special samples (H-32, H-1, H-11, H-12, H-19, H-20, H-35, H-37, H-39, H-6 and H-9). Condensed steam samples were collected every 12 hours, the every week and finally every 15 days, making a total of 592 samples. The chemical analysis were done in two stages because of probable with the chromatograph. In the first stage, 441 samples were run and the rest were run in the second stage. No evidence of the tracer was observed in the monitoring wells. The results confirm the existence of a low-to-moderate permeability, as was previously interpreted using pressure log data. [Spanish] Los Humeros es el tercer campo geotermico de Mexico en el que se realiza una prueba de trazadores organicos empleando alcohol etilico con la finalidad principal de conocer si existe comunicacion entre pozos. El primer campo geotermico en el que se realizo esta prueba fue el de Los Azufres, Michoacan y el segundo el de Las Tres Virgenes, Baja California Sur; en ambos casos se encontro

  18. Estimates of tracer-based piston-flow ages of groundwater from selected sites: National Water-Quality Assessment Program, 2006-2010

    Science.gov (United States)

    Shapiro, Stephanie D.; Plummer, L. Niel; Busenberg, Eurybiades; Widman, Peggy K.; Casile, Gerolamo C.; Wayland, Julian E.; Runkle, Donna L.

    2012-01-01

    Piston-flow age dates were interpreted from measured concentrations of environmental tracers from 812 National Water-Quality Assessment (NAWQA) Program groundwater sites from 27 Study Units across the United States. The tracers of interest include chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), and tritium/helium-3 (3H/3He). Tracer data compiled for this analysis were collected from 2006 to 2010 from groundwater wells in NAWQA studies, including: * Land-Use Studies (LUS, shallow wells, usually monitoring wells, located in recharge areas under dominant land-use settings), * Major-Aquifer Studies (MAS, wells, usually domestic supply wells, located in principal aquifers and representing the shallow drinking water supply), * Flow System Studies (FSS, networks of clustered wells located along a flowpath extending from a recharge zone to a discharge zone, preferably a shallow stream) associated with Land-Use Studies, and * Reference wells (wells representing groundwater minimally impacted by anthropogenic activities) also associated with Land-Use Studies. Tracer data were evaluated using documented methods and are presented as aqueous concentrations, equivalent atmospheric concentrations (for CFCs and SF6), and tracer-based piston-flow ages. Selected ancillary data, such as redox data, well-construction data, and major dissolved-gas (N2, O2, Ar, CH4, and CO2) data, also are presented. Recharge temperature was inferred using climate data (approximated by mean annual air temperature plus 1°C [MAAT +1°C]) as well as major dissolved-gas data (N2-Ar-based) where available. The N2-Ar-based temperatures showed significantly more variation than the climate-based data, as well as the effects of denitrification and degassing resulting from reducing conditions. The N2-Ar-based temperatures were colder than the climate-based temperatures in networks where recharge was limited to the winter months when evapotranspiration was reduced. The tracer-based piston-flow ages

  19. Biodegradation of methanol vapor in a biofilter

    Institute of Scientific and Technical Information of China (English)

    Durai Arulneyam; T. Swaminathan

    2003-01-01

    Volatile organic compounds (VOCs) are a new class of air pollutants posing threat to the environment. Newer technologies are being developed for their control among which biofiltration seem to be most attractive. Biofiltration of methanol vapor from air stream was evaluated in this study. Experimental investigations were conducted on a laboratory scale biofilter, containing mixture of compost and polystyrene inert particles as the filter materials. Mixed consortium of activated sludge was used as an inoculum. The continuous performance of biofilter for methanol removal was monitored for different concentrations and flow rates. The removal efficiencies decreased at higher concentrations and higher gas flow rates. A maximum elimination capacity of 85 g/(m3.h) was achieved. The response of biofilter to upset loading operation showed that the biofilm in the biofilters was quite stable and quickly adapted to adverse operational conditions.

  20. Optimization of metal vapor lasers

    Science.gov (United States)

    Buchanov, V. V.; Molodykh, E. I.; Tykotskii, V. V.

    1983-03-01

    The method proposed here for performing numerical calculations on a computer in order to predict and optimize the characteristics of metal vapor lasers is based on the use of a universal program for numerical experiments designed expressly for metal vapor lasers and on a simultaneous application of an algorithm for multifactor optimization of the output parameters. The latter, in turn, is based on the complex Boks method (Himmelblau, 1970) and on the Gel'fand-Tsetlin ravine method (Himmelblau, 1970). Calculations carried out for a metal with a copper vapor in neon reveal that for optimization with respect to the geometry of the active zone and the parameters of the electrical circuits (including the voltage pulses and excitation frequency) it is sufficient to use the Boks method. The objective function optimum regarding the concentration of the metal particles and the buffer gas found using this algorithm calls for further refinement; this can be performed efficiently with the Gel'fand-Tsetlin ravine method.

  1. Tracer diffusivity and effective temperature in bacterial suspensions

    CERN Document Server

    Patteson, Alison E; Purohit, Prashant K; Arratia, Paulo E

    2015-01-01

    The dynamics of tracer particles in \\textit{E. coli} suspensions are experimentally investigated as a function of particle size and bacteria concentration. We find that tracer diffusivity is enhanced due to particle-bacteria interactions and varies non-monotonically with particle size, exhibiting a peak at sizes comparable to the bacterial length. The time scale characterizing the transition from ballistic to diffusive regime increases monotonically with \\textit{E. coli} concentration and particle size. Diffusivity measurements are then used to estimate suspension effective temperature, which varies nonlinearly with tracer size, suggesting that measures of activity are probe size dependent.

  2. Radionuclide Tracers for Myocardial Perfusion Imaging and Blood Flow Quantification.

    Science.gov (United States)

    deKemp, Robert A; Renaud, Jennifer M; Klein, Ran; Beanlands, Rob S B

    2016-02-01

    Myocardial perfusion imaging is performed most commonly using Tc-99m-sestamibi or tetrofosmin SPECT as well as Rb-82-rubidium or N-13-ammonia PET. Diseased-to-normal tissue contrast is determined by the tracer retention fraction, which decreases nonlinearly with flow. Reduced tissue perfusion results in reduced tracer retention, but the severity of perfusion defects is typically underestimated by 20% to 40%. Compared to SPECT, retention of the PET tracers is more linearly related to flow, and therefore, the perfusion defects are measured more accurately using N-13-ammonia or Rb-82.

  3. Laboratory Testing of Magnetic Tracers for Soil Erosion Measurement*1

    Institute of Scientific and Technical Information of China (English)

    HU Guo-Qing; DONG Yuan-Jie; WANG Hui; QIU Xian-Kui; WANG Yan-Hua

    2011-01-01

    Soil erosion, which includes soil detachment, transport, and deposition, is one of the important dynamic land surface processes. The magnetic tracer method is a useful method for studying soil erosion processes. In this study, five types of magnetic tracers were made with fine soil, fly ash, cement, bentonite, and magnetic powder (reduced iron powder) using the method of disk granulation. The tracers were uniformly mixed with soil and tested in the laboratory using simulated rainfall and inflow experiments to simulate the interrill and rill components of soil erosion, in order to select one or more tracers which could be used to study detachment and deposition by the erosive forces of raindrops and surface flow of water on a slope. The results showed that the five types of magnetic tracers with high magnetic susceptibility and a wide range of sizes had a range of 0.99-1.29 gcm-s in bulk density. In the interrill and rill experiments, the tracers FC1 and FC2 which consisted of fly ash and cement at ratios of 1:1 and 2:1, respectively, were transported in phase with soil particles since the magnetic susceptibility of sediment approximated that of the soil which was uneroded and the slopes of the regression equations between the detachment of sediment and magnetic tracers FC1 and FC2 were very close to the expected value of 20, which was the original soil/tracer ratio. The detachment and deposition on slopes could be accurately reflected by the magnetic susceptibility differences. The change in magnetic susceptibility depended on whether deposition or detachment occurred. However, the tracer FS which consisted of fine soil and the tracers FB1 and FB2 which consisted of fly ash and bentonite at ratios of 1:1 and 2:1, respectively, were all unsuitable for soil erosion study since there was no consistent relationship between sediment and tracer detachment for increasing amounts of runoff. Therefore, the tracers FC1 and FC2 could be used to study soil erosion by water.

  4. Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

    Science.gov (United States)

    Griffis, Timothy J.; Wood, Jeffrey D.; Baker, John M.; Lee, Xuhui; Xiao, Ke; Chen, Zichong; Welp, Lisa R.; Schultz, Natalie M.; Gorski, Galen; Chen, Ming; Nieber, John

    2016-04-01

    Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle - an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m) in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL) over a 3-year period (2010 to 2012). These measurements represent the first set of annual water vapor isotope observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ18Ov ranged from -40.2 to -15.9 ‰ and δ2Hv ranged from -278.7 to -113.0 ‰) and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess (dv) of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in dv, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( > 25 mmol mol-1) indicate that regional evaporation can account

  5. Small Molecule PET Tracers in Drug Discovery.

    Science.gov (United States)

    Donnelly, David J

    2017-09-01

    The process of discovering and developing a new pharmaceutical is a long, difficult, and risky process that requires numerous resources. Molecular imaging techniques such as PET have recently become a useful tool for making decisions along a drug candidate's development timeline. PET is a translational, noninvasive imaging technique that provides quantitative information about a potential drug candidate and its target at the molecular level. Using this technique provides decisional information to ensure that the right drug candidate is being chosen, for the right target, at the right dose within the right patient population. This review will focus on small molecule PET tracers and how they are used within the drug discovery process. PET provides key information about a drug candidate's pharmacokinetic and pharmacodynamic properties in both preclinical and clinical studies. PET is being used in all phases of the drug discovery and development process, and the goal of these studies are to accelerate the process in which drugs are developed. Copyright © 2017. Published by Elsevier Inc.

  6. National Biomedical Tracer Facility: Project definition study

    Energy Technology Data Exchange (ETDEWEB)

    Heaton, R.; Peterson, E. [Los Alamos National Lab., NM (United States); Smith, P. [Smith (P.A.) Concepts and Designs (United States)

    1995-05-31

    The Los Alamos National Laboratory is an ideal institution and New Mexico is an ideal location for siting the National Biomedical Tracer Facility (NBTF). The essence of the Los Alamos proposal is the development of two complementary irradiation facilities that combined with our existing radiochemical processing hot cell facilities and waste handling and disposal facilities provide a low cost alternative to other proposals that seek to satisfy the objectives of the NBTF. We propose the construction of a 30 MeV cyclotron facility at the site of the radiochemical facilities, and the construction of a 100 MeV target station at LAMPF to satisfy the requirements and objectives of the NBTF. We do not require any modifications to our existing radiochemical processing hot cell facilities or our waste treatment and disposal facilities to accomplish the objectives of the NBTF. The total capital cost for the facility defined by the project definition study is $15.2 M. This cost estimate includes $9.9 M for the cyclotron and associated facility, $2.0 M for the 100 MeV target station at LAMPF, and $3.3 M for design.

  7. TRACER STUDY OF RTU GRADUATES: AN ANALYSIS

    Directory of Open Access Journals (Sweden)

    Thelma L. Ramirez

    2014-01-01

    Full Text Available This paper aimed to determine if the field of specialization in the different colleges of RTU graduates and their academic-acquired skills and competencies are related to their present occupations. A modified Graduate Tracer Study (GTS instrument was utilized to gather the quantitative data. Out of 500 questionnaires administered, there were 250 graduates returned answered questionnaires representing the three Colleges: Education, Arts and Sciences, Business and Entrepreneurial Technology. A face to face interview was also conducted in order to support the gathered data. The SPSS was used to generate results from the acquired quantitative data using the frequency counts, percentage and the Chi-square goodness of fit test. The findings revealed that the graduates claimed that their knowledge, academic-acquired skills and competencies contributed greatly in their job performance. The Chi-square goodness of fit proved that there is a significant relationship between the graduates’ fields of specialization and their occupations after graduation. Likewise, the academic-acquired skills and competencies of the graduates are relevant to their chosen occupations. The results further proved that RTU produces marketable and appropriately trained graduates with the majority landing in course-related jobs within a short period after graduation. The study also indicates that the RTU graduates possess the skills and competencies necessary to succeed in this competitive world. However eexpansion of tie-ups with private business entities is made to at least maintain the high employability level of the graduates.

  8. Quantification of joint inflammation in rheumatoid arthritis by time-resolved diffuse optical spectroscopy and tracer kinetic modeling

    Science.gov (United States)

    Ioussoufovitch, Seva; Morrison, Laura B.; Lee, Ting-Yim; St. Lawrence, Keith; Diop, Mamadou

    2015-03-01

    Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation, which can cause progressive joint damage and disability. Diffuse optical spectroscopy (DOS) and imaging have the potential to become potent monitoring tools for RA. We devised a method that combined time-resolved DOS and tracer kinetics modeling to rapidly and reliably quantify blood flow in the joint. Preliminary results obtained from two animals show that the technique can detect joint inflammation as early as 5 days after onset.

  9. Nitrogen metabolism as effect parameter for air pollution in plant bioindicators - a {sup 15}N-tracer study

    Energy Technology Data Exchange (ETDEWEB)

    Hafner, C.; Jung, K.; Schueuermann, G. [UFZ - Umweltforschungszentrum, Leipzig (Germany). Sektion Chemische Oekotoxikologie; Kostka-Rick, R. [Biologisch Ueberwachen und Bewerten, Echterdingen (Germany); Hahn, H.U. [DaimlerChrysler AG, Sindelfingen (Germany)

    2002-07-01

    Since many years, bioindicator plants have been used for effect monitoring of air pollution. In this paper it is demonstrated that the determination of the nitrogen metabolism activity of plants using stable isotope tracer techniques has proven a suitable method for detecting sublethal effects of multiple, low-dose and chronic pollution load. This method permits to diagnose air pollution on a metabolic level of an early stage before visible damages on plants occur. (orig.)

  10. Solute transport processes in a karst vadose zone characterized by long-term tracer tests (the cave system of Postojnska Jama, Slovenia)

    Science.gov (United States)

    Kogovsek, Janja; Petric, Metka

    2014-11-01

    The processes influencing the solute transport in the karst vadose zone were studied by long-term tracer tests with artificial tracers. The results of three successive tracer tests with different modes of injection were compared. Tracer breakthrough curves were monitored at three drips of different hydrological types inside one of the cave galleries of the system of Postojnska Jama over several years. Comparison of the results indicates the highly significant influence of preceding hydrological conditions (dry vs wet), injection mode (artificial flushing vs natural infiltration by subsequent rainfall, and on a bare rock vs on an overlying layer) and geologic heterogeneities within the vadose zone on solute transport in the karst vadose zone. Injection with artificial flushing resulted in rapid infiltration and the tracer traversed almost one hundred meters of bedrock in hours. However, the majority of tracer can be stored within less permeable parts of the vadose zone and then gradually flushed out after additional abundant and intensive precipitation in the period of several years. Long-continued sampling in each of the tests proved to be important for reliable characterization of the long-term solute transport dynamics.

  11. A Systematic Method For Tracer Test Analysis: An Example Using Beowawe Tracer Data

    Energy Technology Data Exchange (ETDEWEB)

    G. Michael Shook

    2005-01-01

    Quantitative analysis of tracer data using moment analysis requires a strict adherence to a set of rules which include data normalization, correction for thermal decay, deconvolution, extrapolation, and integration. If done correctly, the method yields specific information on swept pore volume, flow geometry and fluid velocity, and an understanding of the nature of reservoir boundaries. All calculations required for the interpretation can be done in a spreadsheet. The steps required for moment analysis are reviewed in this paper. Data taken from the literature is used in an example calculation.

  12. Estimated vapor pressure for WTP process streams

    Energy Technology Data Exchange (ETDEWEB)

    Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-01-01

    Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused by organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.

  13. a Thermally Desorbable Miniature Passive Dosimeter for Organic Vapors

    Science.gov (United States)

    Gonzalez, Jesus Antonio

    A thermally desorbable miniature passive dosimeter (MPD) for organic vapors has been developed in conformity with theoretical and practical aspects of passive dosimeter design. The device was optimized for low sample loadings resulting from short-term and/or low concentration level exposure. This was accomplished by the use of thermal desorption rather than solvent elution, which provided the GC method with significantly higher sensitivity. Laboratory evaluation of this device for factors critical to the performance of passive dosimeters using benzene as the test vapor included: desorption efficiency (97.2%), capacity (1400 ppm-min), sensitivity (7ng/sample or 0.06 ppmv for 15 minutes sampling) accuracy and precision, concentration level, environmental conditions (i.e., air face velocity, relative humidity) and sample stability during short (15 minutes) and long periods of time (15 days). This device has demonstrated that its overall accuracy meets NIOSH and OSHA requirements for a sampling and analytical method for the exposure concentration range of 0.1 to 50 ppm (v/v) and 15 minutes exposures. It was demonstrated that the MPD operates in accordance with theoretically predicted performance and should be adequate for short-term and/or low concentration exposure monitoring of organic vapors in the workplace. In addition a dynamic vapor exposure evaluation system for passive dosimeters have been validated using benzene as the test vapor. The system is capable of generating well defined short-square wave concentration profiles suitable for the evaluation of passive dosimeters for ceiling exposure monitoring.

  14. West Twin Creek Alaska Subsurface Bromide Tracer Experiment, 2015

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data was produced as part of a subsurface tracer experiment performed on a boreal hillslope in July, 2015. The data is separated into three files: 'Well...

  15. Microfluidics for Synthesis of Peptide-Based PET Tracers

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2013-01-01

    Full Text Available Positron emission tomography (PET is a powerful noninvasive tool for acquisition of the physiological parameters in human and animals with the help of PET tracers. Among all the PET tracers, radiolabeled peptides have been widely explored for cancer-related receptor imaging due to their high affinity and specificity to receptors. But radiochemistry procedures for production of peptide-based PET tracers are usually complex, which makes large-scale clinical studies relatively challenging. New radiolabeling technologies which could simplify synthesis and purification procedures, are extremely needed. Over the last decade, microfluidics and lab-on-a-chip (LOC technology have boomed as powerful tools in the field of organic chemistry, which potentially provide significant help to the PET chemistry. In this minireview, microfluidic radiolabeling technology is described and its application for synthesis of peptide-based PET tracers is summarized and discussed.

  16. Chlorine isotopes potential as geo-chemical tracers

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Pradhan, U.K.; Banerjee, R.

    The potential of chlorine isotopes as tracers of geo-chemical processes of earth and the oceans is highlighted based on systematic studies carried out in understanding the chlorine isotope fractionation mechanism, its constancy in seawater and its...

  17. Tracking thermal fronts with temperature-sensitive, chemically reactive tracers

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, B.A.; Birdsell, S.A.

    1987-01-01

    Los Alamos is developing tracer techniques using reactive chemicals to track thermal fronts in fractured geothermal reservoirs. If a nonadsorbing tracer flowing from the injection to production well chemically reacts, its reaction rate will be a strong function of temperature. Thus the extent of chemical reaction will be greatest early in the lifetime of the system, and less as the thermal front progresses from the injection to production well. Early laboratory experiments identified tracers with chemical kinetics suitable for reservoirs in the temperature range of 75 to 100/sup 0/C. Recent kinetics studies have focused on the kinetics of hydrolysis of derivatives of bromobenzene. This class of reactions can be used in reservoirs ranging in temperature from 150 to 275/sup 0/C, which is of greater interest to the geothermal industry. Future studies will include laboratory adsorption experiments to identify possibly unwanted adsorption on granite, development of sensitive analytical techniques, and a field demonstration of the reactive tracer concept.

  18. A theoretical framework of tracer methods for marine sediment dynamics

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new theoretical framework of tracer methods is proposed in the present contribution, on the basis of mass conservation. This model is applicable for both artificial and natural tracers. It can be used to calculate the spatial distribution patterns of sediment transport rate, thus providing independent information and verification for the results derived from empirical formulae. For the procedures of the calculation, first, the tracer concentration and topographic maps of two times are obtained. Then, the spatial and temporal changes in the concentration and seabed elevation are calculated, and the boundary conditions required are determined by field observations (such as flow and bedform migration measurements). Finally, based upon eqs. (1) and (13), the transport rate is calculated and expressed as a function of the position over the study area. Further, appropriate modifications to the model may allow the tracer to have different densities and grain size distributions from the bulk sediment.

  19. Monitoreo de emisiones de material particulado de chimeneas de generadores de vapor de la industria azucarera en Tucumán, R. Argentina Monitoring of effluent particulate matter emitted by sugarcane factory stacks in Tucumán

    Directory of Open Access Journals (Sweden)

    Marcos A. Golato

    2012-06-01

    Full Text Available Durante las moliendas en los años 2008, 2009, 2010 y 2011, se realizaron mediciones de las concentraciones de material particulado total (MPT en las emisiones de chimeneas de calderas de la industria azucarera, en Tucumán, R. Argentina. El objetivo de este trabajo fue monitorear la evolución de la concentración y emisión de MPT y observar la influencia de los sistemas de filtrado instalados en las chimeneas de las mencionadas unidades. Se ilustran los datos de las emisiones de MPT obtenidas en los años indicados, con valores promedio por caldera de 58,5 kg/h, 33,6 kg/h, 47,6 kg/h y 33,9 kg/h, respectivamente. Asimismo, este estudio muestra un seguimiento minucioso de un grupo de calderas bagaceras, para determinar la evolución de las emisiones en función de las variables de operación características de esas calderas. Los resultados demostraron la influencia del mantenimiento y de la correcta operación de los equipos de filtrado en la calidad de los gases que fluyen por las chimeneas. Se estudió la influencia de los índices característicos de diseño de los lavadores de gases en la concentración de partículas. Se observó que se ha logrado un menor impacto ambiental a lo largo del tiempo analizado.Total particulate matter (TPM concentrations were measured in stack fumes from sugar factory steam generating boilers in Tucumán in 2008, 2009, 2010 and 2011. The objective of this work was to monitor the evolution of TPM concentrations and emissions and observe the efficiency of filtration systems used in sugarcane factory stacks. Average values of 58.5 kg/h, 33.6 kg/h, 47.6 kg/h and 33.9 kg/h were obtained in 2008, 2009, 2010 and 2011, respectively. Bagasse boilers were also meticulously surveyed to obtain data of the evolution of emissions in relation to specific operation variables of the boilers. Data concerning the quality of effluent gasses from the stacks demonstrated the influence of maintaining and correctly using filtration

  20. Final OSWER Vapor Intrusion Guidance

    Science.gov (United States)

    EPA is preparing to finalize its guidance on assessing and addressing vapor intrusion, which is defined as migration of volatile constituents from contaminated media in the subsurface (soil or groundwater) into the indoor environment. In November 2002, EPA issued draft guidance o...

  1. Simple Chemical Vapor Deposition Experiment

    Science.gov (United States)

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  2. Hydrazine vapor inactivates Bacillus spores

    Science.gov (United States)

    Schubert, Wayne W.; Engler, Diane L.; Beaudet, Robert A.

    2016-05-01

    NASA policy restricts the total number of bacterial spores that can remain on a spacecraft traveling to any planetary body which might harbor life or have evidence of past life. Hydrazine, N2H4, is commonly used as a propellant on spacecraft. Hydrazine as a liquid is known to inactivate bacterial spores. We have now verified that hydrazine vapor also inactivates bacterial spores. After Bacillus atrophaeus ATCC 9372 spores deposited on stainless steel coupons were exposed to saturated hydrazine vapor in closed containers, the spores were recovered from the coupons, serially diluted, pour plated and the surviving bacterial colonies were counted. The exposure times required to reduce the spore population by a factor of ten, known as the D-value, were 4.70 ± 0.50 h at 25 °C and 2.85 ± 0.13 h at 35 °C. These inactivation rates are short enough to ensure that the bioburden of the surfaces and volumes would be negligible after prolonged exposure to hydrazine vapor. Thus, all the propellant tubing and internal tank surfaces exposed to hydrazine vapor do not contribute to the total spore count.

  3. Assessment of Halon-1301 as a groundwater age tracer

    OpenAIRE

    M. Beyer; R. van der Raaij; U. Morgenstern; Jackson, B.(Department of Physics, University of Pennsylvania, Philadelphia, PA, United States)

    2015-01-01

    Groundwater dating is an important tool to assess groundwater resources in regards to their dynamics, i.e. direction and timescale of groundwater flow and recharge, contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However, ambiguous age interpretations are often faced, due to a limited set of available tracers and their individual restricted applicat...

  4. Assessment of Halon-1301 as a groundwater age tracer

    OpenAIRE

    M. Beyer; R. van der Raaij; U. Morgenstern; Jackson, B.(Department of Physics, University of Pennsylvania, Philadelphia, PA, United States)

    2015-01-01

    Groundwater dating is an important tool to assess groundwater resources in regards to their dynamics, i.e. direction and time scale of groundwater flow and recharge, to assess contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However, ambiguous age interpretations are often faced, due to a limited set of available tracers and their in...

  5. Mobility of Metal Tracers in Unsaturated Tuffs of Busted Butte

    Science.gov (United States)

    Groffman, A. R.

    2001-12-01

    A complex tracer mixture was injected continuously for over two years into a 10 m x 10 m x 7 m block of unsaturated tuff as part of the Busted Butte unsaturated-zone tracer test at Yucca Mountain. The test was designed to measure tracer transport within the Topopah Springs and Calico Hills tuffs, units that occur between the potential high-level nuclear waste repository at Yucca Mountain and the water table below. The mixture included nonreactive (Br, I, and fluorinated benzoic acids (FBAs)) and reactive tracers (Li, Ce, Sm, Ni, Co, and Mn). Bromide, I, FBAs, and Li were detected during the test on absorbent pads emplaced in a series of solute collection boreholes located beneath the injectors but the more strongly sorbing metals did not reach the collection boreholes during this period. To determine the distribution and mobility of these metals, tracer constituents were extracted from tuff samples collected during overcoring and mineback of the test block. Tracers were extracted from the tuff samples by leaching with a 5% nitric acid solution for metals and a bicarbonate-carbonate buffer for anions. Results from the overcore sample suite show that metals have migrated through the tuff in the region adjacent to and immediately below the tracer injectors. Consistent with laboratory sorption measurements and observed breakthrough in the collection boreholes, rock analyses showed that Li is the most mobile of the metals. Co and Ni behave similarly, traveling tens of cm from the injection sites, while Sm and Ce moved far less, possibly due to precipitation reactions in addition to sorption. Determination of Mn transport is complicated by high background concentrations in the tuff; additional background samples are currently being evaluated. As expected, our rock analyses show that the nonreactive tracers Br and FBAs have moved beyond the overcore region, corroborating results from collection boreholes.

  6. Tracer dispersion in a percolation network with spatial correlations

    Science.gov (United States)

    Makse; Andrade; Eugene Stanley H

    2000-01-01

    We analyze the transport properties of a neutral tracer in a carrier fluid flowing through percolationlike porous media with spatial correlations. We model convection in the mass transport process using the velocity field obtained by the numerical solution of the Navier-Stokes and continuity equations in the pore space. We find that the resulting statistical properties of the tracer show a transition from a subdiffusion regime at low Peclet number to an enhanced diffusion regime at high Peclet number.

  7. Preliminary evaluation of endogenous milk fluorophores as tracer molecules for curd syneresis.

    Science.gov (United States)

    Fagan, C C; Ferreira, T G; Payne, F A; O'Donnell, C P; O'Callaghan, D J; Castillo, M

    2011-11-01

    A front-face fluorescence spectroscopy probe was installed in the wall of a laboratory-scale cheese vat. Excitation and emission filters were chosen for the selective detection of vitamin A, tryptophan, and riboflavin fluorescence. The evolution of the fluorescence of each fluorophore during milk coagulation and syneresis was monitored to determine if they had the potential to act as intrinsic tracers of syneresis and also coagulation. The fluorescence profiles for 2 of the fluorophores during coagulation could be divided into 3 sections relating to enzymatic hydrolysis of κ-casein, aggregation of casein micelles, and crosslinking. A parameter relating to coagulation kinetics was derived from the tryptophan and riboflavin profiles but this was not possible for the vitamin A response. The study also indicated that tryptophan and riboflavin may act as tracer molecules for syneresis, but this was not shown for vitamin A. The evolution of tryptophan and riboflavin fluorescence during syneresis followed a first-order reaction and had strong relationships with curd moisture and whey total solids content (r=0.86-0.96). Simple 1- and 2-parameter models were developed to predict curd moisture content, curd yield, and whey total solids using parameters derived from the sensor profiles (standard error of prediction=0.0005-0.394%; R(2)=0.963-0.999). The results of this study highlight the potential of tryptophan and riboflavin to act as intrinsic tracer molecules for noninvasive inline monitoring of milk coagulation and curd syneresis. Further work is required to validate these findings under a wider range of processing conditions.

  8. Small Molecule PET Tracers for Transporter Imaging.

    Science.gov (United States)

    Kilbourn, Michael R

    2017-09-01

    As the field of PET has expanded and an ever-increasing number and variety of compounds have been radiolabeled as potential in vivo tracers of biochemistry, transporters have become important primary targets or facilitators of radiotracer uptake and distribution. A transporter can be the primary target through the development of a specific high-affinity radioligand: examples are the multiple high-affinity radioligands for the neuronal membrane neurotransmitter or vesicular transporters, used to image nerve terminals in the brain. The goal of a radiotracer might be to study the function of a transporter through the use of a radiolabeled substrate, such as the application of 3-O-[(11)C]methyl]glucose to measure rates of glucose transport through the blood-brain barrier. In many cases, transporters are required for radiotracer distributions, but the targeted biochemistries might be unrelated: an example is the use of 2-deoxy-2-[(18)F]FDG for imaging glucose metabolism, where initial passage of the radiotracer through cell membranes requires the action of specific glucose transporters. Finally, there are transporters such as p-glycoprotein that function to extrude small molecules from tissues, and can effectively work against successful uptake of radiotracers. The diversity of structures and functions of transporters, their importance in human health and disease, and their role in therapeutic drug disposition suggest that in vivo imaging of transporter location and function will continue to be a point of emphasis in PET radiopharmaceutical development. In this review, the variety of transporters and their importance for in vivo PET radiotracer development and application are discussed. Transporters have thus joined the other major protein targets such as G-protein coupled receptors, ligand-gated ion channels, enzymes, and aggregated proteins as of high interest for understanding human health and disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Boiler for generating high quality vapor

    Science.gov (United States)

    Gray, V. H.; Marto, P. J.; Joslyn, A. W.

    1972-01-01

    Boiler supplies vapor for use in turbines by imparting a high angular velocity to the liquid annulus in heated rotating drum. Drum boiler provides a sharp interface between boiling liquid and vapor, thereby, inhibiting the formation of unwanted liquid droplets.

  10. Determination of stream reaeration coefficients by use of tracers

    Science.gov (United States)

    Kilpatrick, F.A.; Rathbun, R.E.; Yotsukura, Nobuhiro; Parker, G.W.; DeLong, L.L.

    1989-01-01

    Stream reaeration is the physical absorption of oxygen from the atmosphere by a flowing stream. This is the primary process by which a stream replenishes the oxygen consumed in the biodegradation of organic wastes. Prior to 1965, reaeration rate coefficients could be estimated only by indirect methods. In 1965, a direct method of measuring stream reaeration coefficients was developed whereby a radioactive tracer gas was injected into a stream-the principle being that the tracer gas would be desorbed from the stream inversely to how oxygen would be absorbed. The technique has since been modified by substituting hydrocarbon gases for the radioactive tracer gas. This manual describes the slug-injection and constant-rate-injection methods of measuring gas-tracer desorption. Emphasis is on the use of rhodamine WT dye as a relatively conservative tracer and propane as the nonconservative gas tracer, on planning field tests, on methods of injection, sampling, and analysis, and on techniques for computing desorption and reaeration coefficients.

  11. Fourier analysis of multi-tracer cosmological surveys

    CERN Document Server

    Abramo, L Raul; Loureiro, Arthur

    2015-01-01

    We present optimal quadratic estimators for the Fourier analysis of cosmological surveys that detect several different types of tracers of large-scale structure. Our estimators can be used to simultaneously fit the matter power spectrum and the biases of the tracers - as well as redshift-space distortions (RSDs), non-Gaussianities (NGs), or any other effects that are manifested through differences between the clusterings of distinct species of tracers. Our estimators reduce to the one by Feldman, Kaiser & Peacock (ApJ 1994, FKP) in the case of a survey consisting of a single species of tracer. We show that the multi-tracer estimators are unbiased, and that their covariance is given by the inverse of the multi-tracer Fisher matrix (Abramo, MNRAS 2013; Abramo & Leonard, MNRAS 2013). When the biases, RSDs and NGs are fixed to their fiducial values, and one is only interested in measuring the underlying power spectrum, our estimators are projected into the estimator found by Percival, Verde & Peacock ...

  12. Energy spectra and passive tracer cascades in turbulent flows

    CERN Document Server

    Jolly, Michael

    2016-01-01

    We study the influence of the energy spectrum on the extent of the cascade range of a passive tracer in turbulent flows. The interesting cases are when there are two different spectra over the potential range of the tracer cascade (in 2D when the tracer forcing is in the inverse energy cascade range, and in 3D when the Schmidt number Sc is large). The extent of the tracer cascade range is then limited by the width of the range for the shallower of the two energy spectra. Nevertheless, we show that in dimension $d=2,3$ the tracer cascade range extends (up to a logarithm) to $\\kappa_{d\\text{D}}^{p}$, where $\\kappa_{d\\text{D}}$ is the wavenumber beyond which diffusion should dominate and $p$ is arbitrarily close to 1, provided Sc is larger than a certain power (depending on $p$) of the Grashof number. We also derive estimates which suggest that in 2D, for Sc${}\\sim1$ a wide tracer cascade can coexist with a significant inverse energy cascade at Grashof numbers large enough to produce a turbulent flow.

  13. Multi-tracer investigation of river and groundwater interactions: a case study in Nalenggele River basin, northwest China

    Science.gov (United States)

    Xu, Wei; Su, Xiaosi; Dai, Zhenxue; Yang, Fengtian; Zhu, Pucheng; Huang, Yong

    2017-06-01

    Environmental tracers (such as major ions, stable and radiogenic isotopes, and heat) monitored in natural waters provide valuable information for understanding the processes of river-groundwater interactions in arid areas. An integrated framework is presented for interpreting multi-tracer data (major ions, stable isotopes (2H, 18O), the radioactive isotope 222Rn, and heat) for delineating the river-groundwater interactions in Nalenggele River basin, northwest China. Qualitative and quantitative analyses were undertaken to estimate the bidirectional water exchange associated with small-scale interactions between groundwater and surface water. Along the river stretch, groundwater and river water exchange readily. From the high mountain zone to the alluvial fan, groundwater discharge to the river is detected by tracer methods and end-member mixing models, but the river has also been identified as a losing river using discharge measurements, i.e. discharge is bidirectional. On the delta-front of the alluvial fan and in the alluvial plain, in the downstream area, the characteristics of total dissolved solids values, 222Rn concentrations and δ18O values in the surface water, and patterns derived from a heat-tracing method, indicate that groundwater discharges into the river. With the environmental tracers, the processes of river-groundwater interaction have been identified in detail for better understanding of overall hydrogeological processes and of the impacts on water allocation policies.

  14. Monitoring Telluric Water Absorption with CAMAL

    Science.gov (United States)

    Baker, Ashley; Blake, Cullen; Sliski, David

    2017-01-01

    Ground-based observations are severely limited by telluric water vapor absorption features, which are highly variable in time and significantly complicate both spectroscopy and photometry in the near-infrared (NIR). To achieve the stability required to study Earth-sized exoplanets, monitoring the precipitable water vapor (PWV) becomes necessary to mitigate the impact of telluric lines on radial velocity measurements and transit light curves. To address this issue, we present the Camera for the Automatic Monitoring of Atmospheric Lines (CAMAL), a stand-alone, inexpensive 6-inch aperture telescope dedicated to measuring PWV at the Whipple Observatory. CAMAL utilizes three NIR narrowband filters to trace the amount of atmospheric water vapor affecting simultaneous observations with the MINiature Exoplanet Radial Velocity Array (MINERVA) and MINERVA-Red telescopes. We present the current design of CAMAL, discuss our calibration methods, and show PWV measurements taken with CAMAL compared to those of a nearby GPS water vapor monitor.

  15. Vapor Pressure Data Analysis and Statistics

    Science.gov (United States)

    2016-12-01

    VAPOR PRESSURE DATA ANALYSIS AND STATISTICS ECBC-TR-1422 Ann Brozena RESEARCH AND TECHNOLOGY DIRECTORATE...DATE XX-12-2016 2. REPORT TYPE Final 3. DATES COVERED (From - To) Nov 2015 – Apr 2016 4. TITLE Vapor Pressure Data Analysis and Statistics 5a...1 VAPOR PRESSURE DATA ANALYSIS AND STATISTICS 1. INTRODUCTION Knowledge of the vapor pressure of materials as a function of temperature is

  16. HYDROGEL TRACER BEADS: THE DEVELOPMENT, MODIFICATION, AND TESTING OF AN INNOVATIVE TRACER FOR BETTER UNDERSTANDING LNAPL TRANSPORT IN KARST AQUIFERS

    Energy Technology Data Exchange (ETDEWEB)

    Amanda Laskoskie, Harry M. Edenborn, and Dorothy J. Vesper

    2012-01-01

    The goal of this specific research task is to develop proxy tracers that mimic contaminant movement to better understand and predict contaminant fate and transport in karst aquifers. Hydrogel tracer beads are transported as a separate phase than water and can used as a proxy tracer to mimic the transport of non-aqueous phase liquids (NAPL). They can be constructed with different densities, sizes & chemical attributes. This poster describes the creation and optimization of the beads and the field testing of buoyant beads, including sampling, tracer analysis, and quantitative analysis. The buoyant beads are transported ahead of the dissolved solutes, suggesting that light NAPL (LNAPL) transport in karst may occur faster than predicted from traditional tracing techniques. The hydrogel beads were successful in illustrating this enhanced transport.

  17. Water vapor increase in the northern hemispheric lower stratosphere by the Asian monsoon anticyclone observed during TACTS campaign in 2012

    Science.gov (United States)

    Rolf, Christian; Vogel, Bärbel; Hoor, Peter; Günther, Gebhard; Krämer, Martina; Müller, Rolf; Müller, Stephan; Riese, Martin

    2017-04-01

    Water vapor plays a key role in determining the radiative balance in the upper troposphere and lower stratosphere (UTLS) and thus the climate of the Earth (Forster and Shine, 2002; Riese et al., 2012). Therefore a detailed knowledge about transport pathways and exchange processes between troposphere and stratosphere is required to understand the variability of water vapor in this region. The Asian monsoon anticyclone caused by deep convection over and India and east Asia is able to transport air masses from the troposphere into the nothern extra-tropical stratosphere (Müller et al. 2016, Vogel et al. 2016). These air masses contain pollution but also higher amounts of water vapor. An increase in water vapor of about 0.5 ppmv in the extra-tropical stratosphere above a potential temperature of 380 K was detected between August and September 2012 by in-situ instrumentation above the European northern hemisphere during the HALO aircraft mission TACTS. Here, we investigated the origin of this water vapor increase with the help of the 3D Lagrangian chemistry transport model CLaMS (McKenna et al., 2002). We can assign an origin of the moist air masses in the Asian region (North and South India and East China) with the help of model origin tracers. Additionally, back trajectories of these air masses with enriched water vapor are used to differentiate between transport from the Asia monsoon anticyclone and the upwelling of moister air in the tropics particularly from the Pacific and Southeast Asia.

  18. A spreadsheet program for two-well tracer test data analysis.

    Science.gov (United States)

    Tang, Guoping; Watson, David B; Parker, Jack C; Brooks, Scott C

    2012-01-01

    Two-well tracer tests are often conducted to investigate subsurface solute transport in the field. Analyzing breakthrough curves in extraction and monitoring wells using numerical methods is nontrivial due to highly nonuniform flow conditions. We extended approximate analytical solutions for the advection-dispersion equation for an injection-extraction well doublet in a homogeneous confined aquifer under steady-state flow conditions for equal injection and extraction rates with no transverse dispersion and negligible ambient flow, and implemented the solutions in Microsoft Excel using Visual Basic for Application (VBA). Functions were implemented to calculate concentrations in extraction and monitoring wells at any location due to a step or pulse injection. Type curves for a step injection were compared with those calculated by numerically integrating the solution for a pulse injection. The results from the two approaches are similar when the dispersivity is small. As the dispersivity increases, the latter was found to be more accurate but requires more computing time. The code was verified by comparing the results with published-type curves and applied to analyze data from the literature. The method can be used as a first approximation for two-well tracer test design and data analysis, and to check accuracy of numerical solutions. The code and example files are publicly available.

  19. Using seismic reflection to locate a tracer testing complex south of Yucca Mountain, Nye County, Nevada

    Science.gov (United States)

    Kryder, Levi

    Tracer testing in the fractured volcanic aquifer near Yucca Mountain, and in the alluvial aquifer south of Yucca Mountain, Nevada has been conducted in the past to determine the flow and transport properties of groundwater in those geologic units. However, no tracer testing has been conducted across the alluvium/volcanic interface. This thesis documents the investigative process and subsequent analysis and interpretations used to identify a location suitable for installation of a tracer testing complex, near existing Nye County wells south of Yucca Mountain. The work involved evaluation of existing geologic data, collection of wellbore seismic data, and a detailed surface seismic reflection survey. Borehole seismic data yielded useful information on alluvial P-wave velocities. Seismic reflection data were collected over a line of 4.5-km length, with a 10-m receiver and shot spacing. Reflection data were extensively processed to image the alluvium/volcanic interface. A location for installation of an alluvial/volcanic tracer testing complex was identified based on one of the reflectors imaged in the reflection survey; this site is located between existing Nye County monitoring wells, near an outcrop of Paintbrush Tuff. Noise in the reflection data (due to some combination of seismic source signal attenuation, poor receiver-to-ground coupling, and anthropogenic sources) were sources of error that affected the final processed data set. In addition, in some areas low impedance contrast between geologic units caused an absence of reflections in the data, complicating the processing and interpretation. Forward seismic modeling was conducted using Seismic Un*x; however, geometry considerations prevented direct comparison of the modeled and processed data sets. Recommendations for additional work to address uncertainties identified during the course of this thesis work include: drilling additional boreholes to collect borehole seismic and geologic data; reprocessing a

  20. Authentically radiolabelled Mn(II) complexes as bimodal PET/MR tracers

    Energy Technology Data Exchange (ETDEWEB)

    Vanasschen, Christian; Brandt, Marie; Ermert, Johannes [Institute of Neuroscience and Medicine, INM-5 - Nuclear Chemistry, Forschungszentrum Jülich (Germany); Neumaier, Bernd [Institute for Radiochemistry and Experimental Molecular Imaging, Medical Clinics, University of Cologne (Germany); Coenen, Heinz H [Institute of Neuroscience and Medicine, INM-5 - Nuclear Chemistry, Forschungszentrum Jülich (Germany)

    2015-05-18

    The development of small molecule bimodal PET/MR tracers is mainly hampered by the lack of dedicated preparation methods. Authentic radiolabelling of MR contrast agents ensures easy access to such probes: a ligand, chelating a paramagnetic metal ion (e.g. Mn2+) and the corresponding PET isotope (e.g. 52gMn), leads to a “cocktail mixture” where both imaging reporters exhibit the same pharmacokinetics. Paramagnetic [55Mn(CDTA)]2- shows an excellent compromise between thermodynamic stability, kinetic inertness and MR contrast enhancement. Therefore, the aim of this study was to develop new PET/MR tracers by labelling CDTA ligands with paramagnetic manganese and the β+-emitter 52gMn. N.c.a. 52gMn (t1/2: 5.6 d; Eβ+: 575.8 keV (29.6%)) was produced by proton irradiation of a natCr target followed by cation-exchange chromatography. CDTA was radiolabelled with n.c.a. 52gMn2+ in NaOAc buffer (pH 6) at RT. The complex was purified by RP-HPLC and its stability tested in PBS and blood plasma at 37°C. The redox stability was assessed by monitoring the T1 relaxation (20 MHz) in HEPES buffer (pH 7.4). A functionalized CDTA ligand was synthesized in 5 steps. [52gMn(CDTA)]2- was quantitatively formed within 30 min at RT. The complex was stable for at least 6 days in PBS and blood plasma at 37°C and no oxidation occurred within 7 months storage at RT. Labelling CDTA with an isotopic 52g/55Mn2+ mixture led to the corresponding bimodal PET/MR tracer. Furthermore, a functionalized CDTA ligand was synthesized with an overall yield of 18-25%. [52g/55Mn(CDTA)]2-, the first manganese-based bimodal PET/MR tracer prepared, exhibits excellent stability towards decomplexation and oxidation. This makes the functionalized CDTA ligand highly suitable for designing PET/MR tracers with high relaxivity or targeting properties.

  1. Use of rare earth oxide tracers to determine source areas for sediment eroded from arable hillslopes

    Science.gov (United States)

    Deasy, C.; Quinton, J. N.

    2009-04-01

    hillslope, the topslope, midslope, and downslope hillslope segments without tramlines, and the tramline areas. Erosion rates were measured from a number of hillslope areas, and sediment samples were collected from the hillslope areas after a series of rainfall events, and analysed for rare earth element concentrations in order to determine the amounts of different tracers eroded in each event. The results of the paper provide insights into the transport of sediment within arable hillslopes. For example, the upslope section of the hillslope is more important as a sediment source than the downslope area, and much of the applied tracer remained on the hillslope and was not eroded in the monitored rainfall events, suggesting that much of the hillslope area was not connected to the downslope runoff transport pathways.

  2. Sistem Pre Kompilasi Data Tracer Studi Online Ditjen Belmawa Ristekdikti (Studi Kasus: Politeknik Harapan Bersama

    Directory of Open Access Journals (Sweden)

    Very Kurnia Bakti

    2017-01-01

    Full Text Available Tracer studi merupakan salah satu upaya yang diharapkan dapat menyediakan informasi untuk mengevaluasi hasil pendidikan di Politeknik Harapan Bersama dari kuisioner yang diberikan kepada alumni. Kegiatan tracer studi ini sudah dilaksanakan secara online, namun masih terdapat kendala pada bagian sistem yang digunakan saat ini, hal tersebut menyebabkan Politeknik Harapan Bersama tidak dapat melaporkan / mengunggah hasil tracer studi kepada Ditjen Belmawa Ristekdikti, dimana form kuisioner dan data export tracer studi yang dihasilkan berbeda dengan kebutuhan seperti yang tercantum pada surat edaran No. 313/B/SE/2016 tentang pelaksanaan tracer studi di tingkat perguruan tinggi. Mengingat pentingnya tracer studi sebagai umpan balik bagi Politeknik Harapan Bersama, maka perlu solusi untuk mengatasi kekurangan sistem ini. Dengan merubah sistem yang ada dengan sistem tracer studi yang baru merupakan solusi yang tepat dalam permasalahan ini. Sistem tracer studi yang baru mampu menghasilkan data tracer studi alumni dan pengisian form kuisioner sesuai dengan standar Ditjen Belmawa Ristekdikti yang dapat diunggah sistem tracer studi ristekdikti.

  3. Weather and climate analyses using improved global water vapor observations

    National Research Council Canada - National Science Library

    Vonder Haar, Thomas H; Bytheway, Janice L; Forsythe, John M

    2012-01-01

    The NASA Water Vapor Project (NVAP) dataset is a global (land and ocean) water vapor dataset created by merging multiple sources of atmospheric water vapor to form a global data base of total and layered precipitable water vapor...

  4. Are single-well "push-pull" tests suitable tracer methods for aquifer characterization?

    Science.gov (United States)

    Hebig, Klaus; Zeilfelder, Sarah; Ito, Narimitsu; Machida, Isao; Scheytt, Traugott; Marui, Atsunao

    2013-04-01

    Recently, investigations were conducted for geological and hydrogeological characterisation of the sedimentary coastal basin of Horonobe (Hokkaido, Japan). Coastal areas are typical geological settings in Japan, which are less tectonically active than the mountain ranges. In Asia, and especially in Japan, these areas are often densely populated. Therefore, it is important to investigate the behaviour of solutes in such unconsolidated aquifers. In such settings sometimes only single boreholes or groundwater monitoring wells are available for aquifer testing for various reasons, e.g. depths of more than 100 m below ground level and slow groundwater velocities due to density driven flow. A standard tracer test with several involved groundwater monitoring wells is generally very difficult or even not possible at these depths. One of the most important questions in our project was how we can obtain information about chemical and hydraulic properties in such aquifers. Is it possible to characterize solute transport behaviour parameters with only one available groundwater monitoring well or borehole? A so-called "push-pull" test may be one suitable method for aquifer testing with only one available access point. In a push-pull test a known amount of several solutes including a conservative tracer is injected into the aquifer ("push") and afterwards extracted ("pull"). The measured breakthrough curve during the pumping back phase can then be analysed. This method has already been used previously with various aims, also in the recent project (e.g. Hebig et al. 2011, Zeilfelder et al. 2012). However, different test setups produced different tracer breakthrough curves. As no systematic evaluation of this aquifer tracer test method was done so far, nothing is known about its repeatability. Does the injection and extraction rate influence the shape of the breakthrough curve? Which role plays the often applied "chaser", which is used to push the test solution out from the

  5. Copper Ion as a New Leakage Tracer

    Directory of Open Access Journals (Sweden)

    Modaresi J.

    2013-12-01

    Full Text Available Statement of Problem: Most failures of root canal treatments are caused by bacteria. Studies showed that the most common cause of endodontic failures were the incomplete obturation of the root canal and the lack of adequate apical seal. Some in-vitro methods are used to estimate sealing quality, generally by measuring microleakage that allows the tracer agent to penetrate the filled canal.Purpose: Conventional methods of evaluating the seal of endodontically treated teeth are complicated and have some drawbacks. We used copper ion diffusion method to assess the leakage and the results were compared to dye penetration method.Materials and Method: The crowns of 21 extracted teeth were cut off at the CEJ level. After preparing the canals, the teeth were placed in tubes containing saline. They were divided randomly into 15 experimental cases; 3 positive and 3 negative controls. Positive controls were filled by single cone without sealer while the experimental and the negative control groups were filled by lateral technique. The coronal portion of gutta was removed and 9mm was left. The external surface of each tooth was coated with nail polish. Two millimeters of apical portion was immersed into 9ml of distilled water and 0.3ml of CuSO4 solution was injected into the coronal portion. After 2 days, copper sulfate was measured by an atomic absorption spectrophotometer. The teeth were then immersed in 2% methylene blue for 24 hours, sectioned and the extent of dye penetration was measured by a stereomicroscope.Results: The maximum and minimum recorded copper ion concentrations for the experimental group were 18.37 and 2.87ppm respectively. The maximum and minimum recorded dye penetrations for the experimental group were 8.5 and 3.5mm respectively. The statistical analysis, adopting paired samples test, showed poor correlation between average recorded results of two methods.Conclusion: Based on our results, there was no significant correlation between

  6. A copper vapor laser by using a copper-vapor-complex reaction at a low temperature

    OpenAIRE

    Kano, Toshiyuki; Taniguchi, Hiroshi; Saito, Hiroshi

    1987-01-01

    A copper vapor laser performance by using ametal-vapor-complex reaction (Cu+AlBr3) is reported. The laser operation is obtained at a low temperature without externalheating because of the AlBr3 vapors evaporating at a room temperature. The copper vapor laser using this metal-vapor-complex reaction has an advantage of deposition-free of a metallic copper to the laser tube wall, which is different from the copper halide and the organometallic copper lasers.

  7. Assessing preferential flow by simultaneously injecting nanoparticle and chemical tracers

    KAUST Repository

    Subramanian, S. K.

    2013-01-01

    The exact manner in which preferential (e.g., much faster than average) flow occurs in the subsurface through small fractures or permeable connected pathways of other kinds is important to many processes but is difficult to determine, because most chemical tracers diffuse quickly enough from small flow channels that they appear to move more uniformly through the rock than they actually do. We show how preferential flow can be assessed by injecting 2 to 5 nm carbon particles (C-Dots) and an inert KBr chemical tracer at different flow rates into a permeable core channel that is surrounded by a less permeable matrix in laboratory apparatus of three different designs. When the KBr tracer has a long enough transit through the system to diffuse into the matrix, but the C-Dot tracer does not, the C-Dot tracer arrives first and the KBr tracer later, and the separation measures the degree of preferential flow. Tracer sequestration in the matrix can be estimated with a Peclet number, and this is useful for experiment design. A model is used to determine the best fitting core and matrix dispersion parameters and refine estimates of the core and matrix porosities. Almost the same parameter values explain all experiments. The methods demonstrated in the laboratory can be applied to field tests. If nanoparticles can be designed that do not stick while flowing through the subsurface, the methods presented here could be used to determine the degree of fracture control in natural environments, and this capability would have very wide ranging value and applicability.

  8. Testing fundamentals: The chemical state of geochemical tracers in biominerals.

    Science.gov (United States)

    Branson, O.; Redfern, S. A. T.; Read, E.; Elderfield, H.

    2015-12-01

    The use of many carbonate-derived geochemical proxies is underpinned by the assumption that tracer elements are incorporated 'ideally' as impurities the mineral lattice, following relatively straightforward kinetic and thermodynamic drives. This allows comparison to inorganic precipitation experiments, and provides a systematic starting point from which to translate geochemical tracers to environmental records. Biomineral carbonates are a prominent source of geochemical proxy material, and are far from an ideal inorganic system. They are structurally and compositionally heterogeneous mineral-organic composites, produced in tightly controlled biological environments, possibly via non-classical crystal growth mechanisms. Biominerals offer numerous opportunities for tracers to be incorporated in a 'non-ideal' state. For instance, tracers could be hosted within the organic component of the structure, in interstitial micro-domains of a separate mineral phase, or in localized high-impurity clusters. If a proxy element is hosted in a non-ideal state, our understanding of its incorporation and preservation is flawed, and the theoretical basis behind the proxies derived from it must be reevaluated. Thus far, the assumption of ideal tracer incorporation has remained largely untested, owing to the spatial resolution and sensitivity limits of available techniques. Developments in high-resolution, high-sensitivity X-ray spectroscopy at Scanning Transmission X-Ray Microscopes (STXMs) have allowed us to measure trace element coordination in foraminiferal calcite, at length-scales relevant to biomineralisation processes and tracer incorporation. This instrument has allowed us to test the fundamental assumptions behind several geochemical proxy elements. We present a summary of four STXM studies, assessing the chemical state and distribution of Mg (Branson et al, 2014), B (Branson et al, 2015), S and Na (unpub.), and highlight the implications of these data for the use of these

  9. Multiple Tracer Tests in Porous Media During Clogging

    Science.gov (United States)

    Englert, A.; Banning, A.; Siegmund, J.; Freye, S.; Goekpinar, T.

    2015-12-01

    Transport processes are known to be governed by the physical and chemical heterogeneity of the subsurface. Clogging processes can alter this heterogeneity as function of time and thus can modify transport. To understand transport under clogging conditions and to unravel the potential of multiple tracer tests to characterize such transport process we perform column and sandbox experiments. Our recently developed column and sandbox experiments are used to perform multiple tracer tests during clogging. In a first set of experiments, a cubic cell of 0.1 m x 0.1 m x 0.1 m is used to experimentally estimate flow and transport characteristics of an unconsolidated sediment through Darcy and tracer experiments. The water streaming through the experiment is amended with ammonium sulfate permanently. Salt tracers are added to the streaming water repeatedly, to be detected at micro electrodes at the inflow and the outflow of the cubic cell. Through repeated syringe injections of a barium chloride solution into the center of the cubic cell clogging processes are forced to occur around the mixing zone of the injected and streaming water by precipitation of barium sulfate. In a second set of experiments, a sandbox model including a sediment body of 0.3 m x 0.3 m x 0.1 m is used. Tracer, streaming, and injection water chemistry is kept similar to the cubic cell experiments. However, tracer breakthrough is now detected at nine positions within the experiment and at the inflow and the outflow of the sandbox model. Injection of barium chloride solution is now at two locations around the center of the sandbox model. Flow and transport characteristics of the sediment body are estimated based on Darcy and tracer experiments, which are performed repeatedly. Combined analysis of local and ensemble breakthrough curves and integrated numerical modeling will be used to understand effective and local flow and transport in a in a porous medium during clogging.

  10. What Good is Raman Water Vapor Lidar?

    Science.gov (United States)

    Whitman, David

    2011-01-01

    Raman lidar has been used to quantify water vapor in the atmosphere for various scientific studies including mesoscale meteorology and satellite validation. Now the international networks of NDACC and GRUAN have interest in using Raman water vapor lidar for detecting trends in atmospheric water vapor concentrations. What are the data needs for addressing these very different measurement challenges. We will review briefly the scientific needs for water vapor accuracy for each of these three applications and attempt to translate that into performance specifications for Raman lidar in an effort to address the question in the title of "What good is Raman water vapor Iidar."

  11. High temperature vapors science and technology

    CERN Document Server

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  12. Conductometric Sensors for Detection of Elemental Mercury Vapor

    Science.gov (United States)

    Ryan, M. A.; Homer, M. L.; Shevade, A. V.; Lara, L. M.; Yen, S.-P. S.; Kisor, A. K.; Manatt, K. S.

    2008-01-01

    Several organic and inorganic materials have been tested for possible incorporation into a sensing array in order to add elemental mercury vapor to the suite of chemical species detected. Materials have included gold films, treated gold films, polymer-carbon composite films, gold-polymer-carbon composite films and palladium chloride sintered films. The toxicity of mercury and its adverse effect on human and animal health has made environmental monitoring of mercury in gas and liquid phases important (1,2). As consumer products which contain elemental mercury, such as fluorescent lighting, become more widespread, the need to monitor environments for the presence of vapor phase elemental mercury will increase. Sensors in use today to detect mercury in gaseous streams are generally based on amalgam formation with gold or other metals, including noble metals and aluminum. Recently, NASA has recognized a need to detect elemental mercury vapor in the breathing atmosphere of the crew cabin in spacecraft and has requested that such a capability be incorporated into the JPL Electronic Nose (3). The detection concentration target for this application is 10 parts-per-billion (ppb), or 0.08 mg/m3. In order to respond to the request to incorporate mercury sensing into the JPL Electronic Nose (ENose) platform, it was necessary to consider only conductometric methods of sensing, as any other transduction method would have required redesign of the platform. Any mercury detection technique which could not be incorporated into the existing platform, such as an electrochemical technique, could not be considered.

  13. 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.

  14. Vapor stabilizing surfaces for superhydrophobicity

    Science.gov (United States)

    Patankar, Neelesh

    2010-11-01

    The success of rough substrates designed for superhydrophobicity relies crucially on the presence of air pockets in the roughness grooves. This air is supplied by the surrounding environment. However, if the rough substrates are used in enclosed configurations, such as in fluidic networks, the air pockets may not be sustained in the roughness grooves. In this work a design approach based on sustaining a vapor phase of the liquid in the roughness grooves, instead of relying on the presence of air, is explored. The resulting surfaces, referred to as vapor stabilizing substrates, are deemed to be robust against wetting transition even if no air is present. Applications of this approach include low drag surfaces, nucleate boiling, and dropwise condensation heat transfer, among others.

  15. Vaporization chambers and associated methods

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Terry D.; Wilding, Bruce M.; McKellar, Michael G.; Shunn, Lee P.

    2017-02-21

    A vaporization chamber may include at least one conduit and a shell. The at least one conduit may have an inlet at a first end, an outlet at a second end and a flow path therebetween. The shell may surround a portion of each conduit and define a chamber surrounding the portion of each conduit. Additionally, a plurality of discrete apertures may be positioned at longitudinal intervals in a wall of each conduit, each discrete aperture of the plurality of discrete apertures sized and configured to direct a jet of fluid into each conduit from the chamber. A liquid may be vaporized by directing a first fluid comprising a liquid into the inlet at the first end of each conduit, directing jets of a second fluid into each conduit from the chamber through discrete apertures in a wall of each conduit and transferring heat from the second fluid to the first fluid.

  16. Internal Water Vapor Photoacoustic Calibration

    Science.gov (United States)

    Pilgrim, Jeffrey S.

    2009-01-01

    Water vapor absorption is ubiquitous in the infrared wavelength range where photoacoustic trace gas detectors operate. This technique allows for discontinuous wavelength tuning by temperature-jumping a laser diode from one range to another within a time span suitable for photoacoustic calibration. The use of an internal calibration eliminates the need for external calibrated reference gases. Commercial applications include an improvement of photoacoustic spectrometers in all fields of use.

  17. Water vapor diffusion membrane development

    Science.gov (United States)

    Tan, M. K.

    1977-01-01

    An application of the water vapor diffusion technique is examined whereby the permeated water vapor is vented to space vacuum to alleviate on-board waste storage and provide supplemental cooling. The work reported herein deals primarily with the vapor diffusion-heat rejection (VD-HR) as it applies to the Space Shuttle. A stack configuration was selected, designed and fabricated. An asymmetric cellulose acetate membrane, used in reverse osmosis application was selected and a special spacer was designed to enhance mixing and promote mass transfer. A skid-mount unit was assembled from components used in the bench unit although no attempt was made to render it flight-suitable. The operating conditions of the VD-HR were examined and defined and a 60-day continuous test was carried out. The membranes performed very well throughout the test; no membrane rupture and no unusual flux decay was observed. In addition, a tentative design for a flight-suitable VD-HR unit was made.

  18. Critical points of metal vapors

    Energy Technology Data Exchange (ETDEWEB)

    Khomkin, A. L., E-mail: alhomkin@mail.ru; Shumikhin, A. S. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2015-09-15

    A new method is proposed for calculating the parameters of critical points and binodals for the vapor–liquid (insulator–metal) phase transition in vapors of metals with multielectron valence shells. The method is based on a model developed earlier for the vapors of alkali metals, atomic hydrogen, and exciton gas, proceeding from the assumption that the cohesion determining the basic characteristics of metals under normal conditions is also responsible for their properties in the vicinity of the critical point. It is proposed to calculate the cohesion of multielectron atoms using well-known scaling relations for the binding energy, which are constructed for most metals in the periodic table by processing the results of many numerical calculations. The adopted model allows the parameters of critical points and binodals for the vapor–liquid phase transition in metal vapors to be calculated using published data on the properties of metals under normal conditions. The parameters of critical points have been calculated for a large number of metals and show satisfactory agreement with experimental data for alkali metals and with available estimates for all other metals. Binodals of metals have been calculated for the first time.

  19. TracerLPM (Version 1): An Excel® workbook for interpreting groundwater age distributions from environmental tracer data

    Science.gov (United States)

    Jurgens, Bryant C.; Böhlke, J.K.; Eberts, Sandra M.

    2012-01-01

    TracerLPM is an interactive Excel® (2007 or later) workbook program for evaluating groundwater age distributions from environmental tracer data by using lumped parameter models (LPMs). Lumped parameter models are mathematical models of transport based on simplified aquifer geometry and flow configurations that account for effects of hydrodynamic dispersion or mixing within the aquifer, well bore, or discharge area. Five primary LPMs are included in the workbook: piston-flow model (PFM), exponential mixing model (EMM), exponential piston-flow model (EPM), partial exponential model (PEM), and dispersion model (DM). Binary mixing models (BMM) can be created by combining primary LPMs in various combinations. Travel time through the unsaturated zone can be included as an additional parameter. TracerLPM also allows users to enter age distributions determined from other methods, such as particle tracking results from numerical groundwater-flow models or from other LPMs not included in this program. Tracers of both young groundwater (anthropogenic atmospheric gases and isotopic substances indicating post-1940s recharge) and much older groundwater (carbon-14 and helium-4) can be interpreted simultaneously so that estimates of the groundwater age distribution for samples with a wide range of ages can be constrained. TracerLPM is organized to permit a comprehensive interpretive approach consisting of hydrogeologic conceptualization, visual examination of data and models, and best-fit parameter estimation. Groundwater age distributions can be evaluated by comparing measured and modeled tracer concentrations in two ways: (1) multiple tracers analyzed simultaneously can be evaluated against each other for concordance with modeled concentrations (tracer-tracer application) or (2) tracer time-series data can be evaluated for concordance with modeled trends (tracer-time application). Groundwater-age estimates can also be obtained for samples with a single tracer measurement at one

  20. Natural organic compounds as tracers for biomass combustion in aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Simoneit, B.R.T. [Brookhaven National Lab., Upton, NY (United States)]|[Oregon State Univ., Corvallis, OR (United States). Coll. of Oceanic and Atmospheric Sciences; Abas, M.R. bin [Brookhaven National Lab., Upton, NY (United States)]|[Univ. of Malaya, Kuala Lumpur (Malaysia); Cass, G.R. [Brookhaven National Lab., Upton, NY (United States)]|[California Inst. of Tech., Pasadena, CA (United States). Environmental Engineering Science Dept.; Rogge, W.F. [Brookhaven National Lab., Upton, NY (United States)]|[Florida International Univ., University Park, FL (United States). Dept. of Civil and Environmental Engineering; Mazurek, M.A. [Brookhaven National Lab., Upton, NY (United States); Standley, L.J. [Academy of Natural Sciences, Avondale, PA (United States). Stroud Water Research Center; Hildemann, L.M. [Stanford Univ., CA (United States). Dept. of Civil Engineering

    1995-08-01

    Biomass combustion is an important primary source of carbonaceous particles in the global atmosphere. Although various molecular markers have already been proposed for this process, additional specific organic tracers need to be characterized. The injection of natural product organic tracers to smoke occurs primarily by direct volatilization/steam stripping and by thermal alteration based on combustion temperature. The degree of alteration increases as the burn temperature rises and the moisture content of the fuel decreases. Although the molecular composition of organic matter in smoke particles is highly variable, the molecular structures of the tracers are generally source specific. The homologous compound series and biomarkers present in smoke particles are derived directly from plant wax, gum and resin by volatilization and secondarily from pyrolysis of biopolymers, wax, gum and resin. The complexity of the organic components of smoke aerosol is illustrated with examples from controlled burns of temperate and tropical biomass fuels. Burning of biomass from temperate regions (i.e., conifers) yields characteristic tracers from diterpenoids as well as phenolics and other oxygenated species, which are recognizable in urban airsheds. The major organic components of smoke particles from tropical biomass are straight-chain, aliphatic and oxygenated compounds and triterpenoids. The precursor-to-product approach of organic geochemistry can be applied successfully to provide tracers for studying smoke plume chemistry and dispersion.

  1. Passive Tracer Dynamics in 4 Point-Vortex Flow

    CERN Document Server

    Laforgia, A; Kuznetsov, L V; Zaslavsky, G M

    2000-01-01

    The advection of passive tracers in a system of 4 identical point vortices is studied when the motion of the vortices is chaotic. The phenomenon of vortex-pairing has been observed and statistics of the pairing time is computed. The distribution exhibits a power-law tail with exponent (\\sim 3.6), implying finite average pairing time. Tracer motion is studied for a chosen initial condition of the vortex system. Accessible phase space is investigated. The size of the cores around the vortices is well approximated by the minimum inter-vortex distance and stickiness to these cores is observed. We investigate the origin of stickiness which we link to the phenomenon of vortex pairing and jumps of tracers between cores. Motion within the core is considered and fluctuations are shown to scale with tracer-vortex distance (r) as (r^{6}). No outward or inward diffusion of tracers are observed. This investigation allows the separation of the accessible phase space in four distinct regions, each with its own specific prop...

  2. Vertical Distribution of Ozone and Nitric Acid Vapor on the Mammoth Mountain, Eastern Sierra Nevada, California

    OpenAIRE

    2002-01-01

    In August and September 1999 and 2000, concentrations of ozone (O3) and nitric acid vapor (HNO3) were monitored at an elevation gradient (2184–3325 m) on the Mammoth Mountain, eastern Sierra Nevada, California. Passive samplers were used for monitoring exposure to tropospheric O3 and HNO3 vapor. The 2-week average O3 concentrations ranged between 45 and 72 ppb, while HNO3 concentrations ranged between 0.06 and 0.52 μg/m3. Similar ranges of O3 and HNO3 were determined for 2 years of the study....

  3. Error analysis of integrated water vapor measured by CIMEL photometer

    Science.gov (United States)

    Berezin, I. A.; Timofeyev, Yu. M.; Virolainen, Ya. A.; Frantsuzova, I. S.; Volkova, K. A.; Poberovsky, A. V.; Holben, B. N.; Smirnov, A.; Slutsker, I.

    2017-01-01

    Water vapor plays a key role in weather and climate forming, which leads to the need for continuous monitoring of its content in different parts of the Earth. Intercomparison and validation of different methods for integrated water vapor (IWV) measurements are essential for determining the real accuracies of these methods. CIMEL photometers measure IWV at hundreds of ground-based stations of the AERONET network. We analyze simultaneous IWV measurements performed by a CIMEL photometer, an RPG-HATPRO MW radiometer, and a FTIR Bruker 125-HR spectrometer at the Peterhof station of St. Petersburg State University. We show that the CIMEL photometer calibrated by the manufacturer significantly underestimates the IWV obtained by other devices. We may conclude from this intercomparison that it is necessary to perform an additional calibration of the CIMEL photometer, as well as a possible correction of the interpretation technique for CIMEL measurements at the Peterhof site.

  4. A simple deep monitoring well dilution technique.

    Science.gov (United States)

    Rogiers, Bart; Labat, Serge; Gedeon, Matej; Vandersteen, Katrijn

    2015-04-01

    Well dilution techniques are well known and studied as one of the basic techniques to quantify groundwater fluxes. A typical well dilution test consists of the injection of a tracer, a mixing mechanism (e.g. water circulation with a pump) to achieve a homogeneous concentration distribution within the well, and monitoring of the evolution of tracer concentration with time. An apparent specific discharge can be obtained from such a test, and when details on the well construction are known, it can be converted into a specific discharge representative of the undisturbed aquifer. For deep wells however, the injection of tracer becomes less practical and the use of pumps for circulating and mixing the water becomes problematic. This is due to the limited pressure that common pumps can endure at the outlet, as well as the large volume of water that makes it difficult to achieve a homogeneous concentration, and the impracticalities of getting a lot of equipment to large depths in very small monitoring wells. Injection and monitoring of tracer at a specific depth omits several of the problems with deep wells. We present a very simple device that can be used to perform a dilution test at a specific depth in deep wells. The injection device consists of a PVC tube with a detachable rubber seal at its bottom. To minimize disturbance of the water column in the well, we integrated an EC sensor in this injection device, which enables us to use demineralized water or dissolved salts as a tracer. Once at the target depth, the PVC tube is retracted and the EC sensor and tracer become subject to groundwater flow. The device was tested on a shallow well, on which different types of dilution tests were performed. The results of the other tests agree well with the injection tube results. Finally, the device was used to perform a dilution test in a deep well in order to demonstrate the feasibility of the approach.

  5. EPA Biofuels Research: Biofuel Vapor Generation and Monitoring Methods

    Science.gov (United States)

    The interest in renewable fuels and alternative energy sources has stimulated development of alternatives to traditional petroleum-based fuels. The EPA's Office of Transportation Air Quality (OTAQ) requires information regarding the potential health hazards ofthese fuels regardin...

  6. Investigation of helical flow by using tracer technique

    Directory of Open Access Journals (Sweden)

    Hacıyakupoğlu S.

    2013-05-01

    Full Text Available The flow through coiled tubes is, in practice, important for pipe systems, heat exchangers, chemical reactors, mixers of different gas components, etc., and is physically interesting because of the peculiar characteristics caused by the centrifugal force. Therefore, it is not so easy to observe flow parameters in the helical pipe experimentally. Tracer techniques are being increasingly used to determine characteristics such as volume flow rate, residence time, dispersion and mixing process in industry. In this study, the flow in the helical pipe was obtained in the laboratory and investigated by using the tracer technique. The experimental system including the helical pipe was set up in the laboratory. In the experiments methylene-blue (C16H17N3S has been used as the tracer. The experiments were successfully performed with different flow rates and their results were evaluated with the flow parameters.

  7. Theoretical model of intravascular paramagnetic tracers effect on tissue relaxation

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G

    2006-01-01

    that the relaxivity of intravascular contrast agents depends significantly on the host tissue. This agrees with experimental data by Johnson et al. (Magn Reson Med 2000;44:909). In particular, the present results suggest a several-fold increase in the relaxivity of Gd-based contrast agents in brain tissue compared...... with bulk blood. The enhancement of relaxation in tissue is due to the contrast in magnetic susceptibility between blood vessels and parenchyma induced by the presence of paramagnetic tracer. Beyond the perfusion measurements, the results can be applied to quantitation of functional MRI and to vessel size......The concentration of MRI tracers cannot be measured directly by MRI and is commonly evaluated indirectly using their relaxation effect. This study develops a comprehensive theoretical model to describe the transverse relaxation in perfused tissue caused by intravascular tracers. The model takes...

  8. Preparation of intravenous cholesterol tracer using current good manufacturing practices.

    Science.gov (United States)

    Lin, Xiaobo; Ma, Lina; Racette, Susan B; Swaney, William P; Ostlund, Richard E

    2015-12-01

    Studies of human reverse cholesterol transport require intravenous infusion of cholesterol tracers. Because insoluble lipids may pose risk and because it is desirable to have consistent doses of defined composition available over many months, we investigated the manufacture of cholesterol tracer under current good manufacturing practice (CGMP) conditions appropriate for phase 1 investigation. Cholesterol tracer was prepared by sterile admixture of unlabeled cholesterol or cholesterol-d7 in ethanol with 20% Intralipid(®). The resulting material was filtered through a 1.2 micron particulate filter, stored at 4°C, and tested at time 0, 1.5, 3, 6, and 9 months for sterility, pyrogenicity, autoxidation, and particle size and aggregation. The limiting factor for stability was a rise in thiobarbituric acid-reacting substances of 9.6-fold over 9 months (P postproduction. CGMP manufacturing methods can be achieved in the academic setting and need to be considered for critical components of future metabolic studies.

  9. Heats of vaporization of room temperature ionic liquids by tunable vacuum ultraviolet photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; To, Albert; Koh, Christine; Strasser, Daniel; Kostko, Oleg; Leone, Stephen R.

    2009-11-25

    The heats of vaporization of the room temperature ionic liquids (RTILs) N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide, N-butyl-N-methylpyrrolidinium dicyanamide, and 1-butyl-3-methylimidazolium dicyanamide are determined using a heated effusive vapor source in conjunction with single photon ionization by a tunable vacuum ultraviolet synchrotron source. The relative gas phase ionic liquid vapor densities in the effusive beam are monitored by clearly distinguished dissociative photoionization processes via a time-of-flight mass spectrometer at a tunable vacuum ultraviolet beamline 9.0.2.3 (Chemical Dynamics Beamline) at the Advanced Light Source synchrotron facility. Resulting in relatively few assumptions, through the analysis of both parent cations and fragment cations, the heat of vaporization of N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide is determined to be Delta Hvap(298.15 K) = 195+-19 kJ mol-1. The observed heats of vaporization of 1-butyl-3-methylimidazolium dicyanamide (Delta Hvap(298.15 K) = 174+-12 kJ mol-1) and N-butyl-N-methylpyrrolidinium dicyanamide (Delta Hvap(298.15 K) = 171+-12 kJ mol-1) are consistent with reported experimental values using electron impact ionization. The tunable vacuum ultraviolet source has enabled accurate measurement of photoion appearance energies. These appearance energies are in good agreement with MP2 calculations for dissociative photoionization of the ion pair. These experimental heats of vaporization, photoion appearance energies, and ab initio calculations corroborate vaporization of these RTILs as intact cation-anion ion pairs.

  10. Performances of electrically heated microgroove vaporizers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An electrically heated microgroove vaporizer was proposed. The vaporizer mainly comprised an outer tube, an inner tube and an electrical heater cartridge. Microgrooves were fabricated on the external surface of the inner tube by micro-cutting method,which formed the flow passage for fluid between the external surface of the inner tube and the internal surface of the outer tube.Experiments related to the temperature rise response of water and the thermal conversion efficiency of vaporizer were done to estimate the influences of microgroove's direction, feed flow rate and input voltage on the performances of the vaporizer. The results indicate that the microgroove's direction dominates the vaporizer performance at a lower input voltage. The longitudina lmicrogroove vaporizer exhibits the best performances for the temperature rise response of water and thermal conversion efficiency of vaporizer. For a moderate input voltage, the microgroove's direction and the feed flow rate of water together govern the vaporizer performances. The input voltage becomes the key influencing factor when the vaporizer works at a high input voltage, resulting in the similar performances of longitudinal, oblique and latitudinal microgroove vaporizers.

  11. Dynamics and mechanics of bed-load tracer particles

    Directory of Open Access Journals (Sweden)

    C. B. Phillips

    2014-12-01

    Full Text Available Understanding the mechanics of bed load at the flood scale is necessary to link hydrology to landscape evolution. Here we report on observations of the transport of coarse sediment tracer particles in a cobble-bedded alluvial river and a step-pool bedrock tributary, at the individual flood and multi-annual timescales. Tracer particle data for each survey are composed of measured displacement lengths for individual particles, and the number of tagged particles mobilized. For single floods we find that measured tracer particle displacement lengths are exponentially distributed; the number of mobile particles increases linearly with peak flood Shields stress, indicating partial bed load transport for all observed floods; and modal displacement distances scale linearly with excess shear velocity. These findings provide quantitative field support for a recently proposed modeling framework based on momentum conservation at the grain scale. Tracer displacement is weakly negatively correlated with particle size at the individual flood scale; however cumulative travel distance begins to show a stronger inverse relation to grain size when measured over many transport events. The observed spatial sorting of tracers approaches that of the river bed, and is consistent with size-selective deposition models and laboratory experiments. Tracer displacement data for the bedrock and alluvial channels collapse onto a single curve – despite more than an order of magnitude difference in channel slope – when variations of critical Shields stress and flow resistance between the two are accounted for. Results show how bed load dynamics may be predicted from a record of river stage, providing a direct link between climate and sediment transport.

  12. How well do different tracers constrain the firn diffusivity profile?

    Directory of Open Access Journals (Sweden)

    C. M. Trudinger

    2013-02-01

    Full Text Available Firn air transport models are used to interpret measurements of the composition of air in firn and bubbles trapped in ice in order to reconstruct past atmospheric composition. The diffusivity profile in the firn is usually calibrated by comparing modelled and measured concentrations for tracers with known atmospheric history. However, in most cases this is an under-determined inverse problem, often with multiple solutions giving an adequate fit to the data (this is known as equifinality. Here we describe a method to estimate the firn diffusivity profile that allows multiple solutions to be identified, in order to quantify the uncertainty in diffusivity due to equifinality. We then look at how well different combinations of tracers constrain the firn diffusivity profile. Tracers with rapid atmospheric variations like CH3CCl3, HFCs and 14CO2 are most useful for constraining molecular diffusivity, while &delta:15N2 is useful for constraining parameters related to convective mixing near the surface. When errors in the observations are small and Gaussian, three carefully selected tracers are able to constrain the molecular diffusivity profile well with minimal equifinality. However, with realistic data errors or additional processes to constrain, there is benefit to including as many tracers as possible to reduce the uncertainties. We calculate CO2 age distributions and their spectral widths with uncertainties for five firn sites (NEEM, DE08-2, DSSW20K, South Pole 1995 and South Pole 2001 with quite different characteristics and tracers available for calibration. We recommend moving away from the use of a firn model with one calibrated parameter set to infer atmospheric histories, and instead suggest using multiple parameter sets, preferably with multiple representations of uncertain processes, to assist in quantification of the uncertainties.

  13. How well do different tracers constrain the firn diffusivity profile?

    Directory of Open Access Journals (Sweden)

    C. M. Trudinger

    2012-07-01

    Full Text Available Firn air transport models are used to interpret measurements of the composition of air in firn and bubbles trapped in ice in order to reconstruct past atmospheric composition. The diffusivity profile in the firn is usually calibrated by comparing modelled and measured concentrations for tracers with known atmospheric history. However, in some cases this is an under-determined inverse problem, often with multiple solutions giving an adequate fit to the data (this is known as equifinality. Here we describe a method to estimate the firn diffusivity profile that allows multiple solutions to be identified, in order to quantify the uncertainty in diffusivity due to equifinality. We then look at how well different combinations of tracers constrain the firn diffusivity profile. Tracers with rapid atmospheric variations like CH3CCl3, HFCs and 14CO2 are most useful for constraining molecular diffusivity, while δ15N2 is useful for constraining parameters related to convective mixing near the surface. When errors in the observations are small and Gaussian, three carefully selected tracers are able to constrain the molecular diffusivity profile well with minimal equifinality. However, with realistic data errors or additional processes to constrain, there is benefit to including as many tracers as possible to reduce the uncertainties. We calculate CO2 age distributions and their spectral widths with uncertainties for five firn sites (NEEM, DE08-2, DSSW20K, South Pole 1995 and South Pole 2001 with quite different characteristics and tracers available for calibration. We recommend moving away from the use of a single firn model with one calibrated parameter set to infer atmospheric histories, and instead suggest using multiple parameter sets, preferably with multiple representations of uncertain processes, to allow quantification of the uncertainties.

  14. Rebuilding sources of linear tracers after atmospheric concentration measurements

    Directory of Open Access Journals (Sweden)

    J.-P. Issartel

    2003-01-01

    Full Text Available The identification of widespread sources of passive tracers out of atmospheric concentration measurements has become an important challenge of modern meteorology. The paper proposes some mathematical tracks to address the reconstruction of the complex space-time geometry of the sources of linear tracers. The methods are based upon the use of retroplumes. The inverse problem is addressed in a deterministic non statistical frame. The information obtained by local measurements is spread by introducing the concept of illumination. The constraint that the source is non negative is also addressed. The experimental source ETEX1 is rebuilt in order to evaluate an impulse response of the algorithms.

  15. Streamwise decrease of the 'unsteady' virtual velocity of gravel tracers

    Science.gov (United States)

    Klösch, Mario; Gmeiner, Philipp; Habersack, Helmut

    2017-04-01

    Gravel tracers are usually inserted and transported on top of the riverbed, before they disperse vertically and laterally due to periods of intense bedload, the passage of bed forms, lateral channel migration and storage on bars. Buried grains have a lower probability of entrainment, resulting in a reduction of overall mobility, and, on average, in a deceleration of the particles with distance downstream. As a consequence, the results derived from tracer experiments and their significance for gravel transport may depend on the time scale of the investigation period, complicating the comparison of results from different experiments. We developed a regression method, which establishes a direct link between the transport velocity and the unsteady flow variables to yield an 'unsteady' virtual velocity, while considering the tracer slowdown with distance downstream in the regression. For that purpose, the two parameters of a linear excess shear velocity formula (the critical shear velocity u*c and coefficient a) were defined as functions of the travelled distance since the tracer's insertion. Application to published RFID tracer data from the Mameyes River, Puerto Rico, showed that during the investigation period the critical shear velocity u*c of tracers representing the median bed particle diameter (0.11 m) increased from 0.36 m s-1 to 0.44 m s-1, while the coefficient a decreased from the dimensionless value of 4.22 to 3.53, suggesting a reduction of the unsteady virtual velocity at the highest shear velocity in the investigation period from 0.40 m s-1 to 0.08 m s-1. Consideration of the tracer slowdown improved the root mean square error of the calculated mean displacements of the median bed particle diameter from 8.82 m to 0.34 m. As in previous work these results suggest the need of considering the history of transport when deriving travel distances and travel velocities, depending on the aim of the tracer study. The introduced method now allows estimating the

  16. Observation of individual tracer atoms in an ultracold dilute gas

    CERN Document Server

    Hohmann, Michael; Lausch, Tobias; Mayer, Daniel; Schmidt, Felix; Lutz, Eric; Widera, Artur

    2016-01-01

    Understanding the motion of a tracer particle in a rarefied gas is of fundamental and practical importance. We report the experimental investigation of individual Cs atoms impinging on a dilute cloud of ultracold Rb atoms with variable density. We study the nonequilibrium relaxation of the initial nonthermal state and detect the effect of single collisions which has eluded observation so far. We show that after few collisions, the measured spatial distribution of the light tracer atoms is correctly described by a generalized Langevin equation with a velocity-dependent friction coefficient, over a large range of Knudsen numbers.

  17. Tracer Cycles and Water Ages in Heterogeneous Catchments and Aquifers

    Science.gov (United States)

    Kirchner, J. W.; Jasechko, S.

    2015-12-01

    Estimates of catchment mean transit times are often based on seasonal cycles of stable isotope tracers in precipitation and streamflow. In many cases these transit time estimates are derived directly from sine-wave fitting to the observed seasonal isotope cycles. Broadly similar results are also obtained from time-domain convolutions or explicit tracer modeling, because here too the dominant tracer signal that these techniques seek to match is the seasonal isotopic cycle. Here I use simple benchmark tests to show that estimates of mean transit times based on seasonal tracer cycles will typically be wrong by several hundred percent, when applied to catchments with realistic degrees of spatial heterogeneity. This aggregation bias arises from the strong nonlinearity in the relationship between tracer cycle amplitude and mean travel time. A similar bias arises in estimates of mean transit times in nonstationary catchments. Since typical real-world catchments are both spatially heterogeneous and nonstationary, this analysis poses a fundamental challenge to tracer-based estimates of mean transit times. I propose an alternative storage metric, the fraction of "young water" in streamflow, defined as the fraction of runoff with transit times of less than roughly 0.2 years. I show that young water fractions are virtually free of aggregation bias; that is, they can be accurately estimated from tracer cycles in highly heterogeneous mixtures of subcatchments with strongly contrasting transit time distributions. They can also be reliably estimated in strongly nonstationary catchments. Young water fractions can be estimated separately for individual flow regimes, allowing direct determination of how shifts in hydraulic regime alter the fraction of water reaching the stream by fast flowpaths. One can also estimate the chemical composition of idealized "young water" and "old water" end-members, using relationships between young water fractions and solute concentrations across

  18. North Atlantic ventilation using chlorofluorocarbons and idealised-tracer simulations

    Directory of Open Access Journals (Sweden)

    Yan-Chun He

    2012-10-01

    Full Text Available The simulated chlorofluorocarbon CFC-11 and 29 geographically defined CFC-11 tracers, as well as 29 geographically defined idealised tracers, are used to quantify the regional contribution to the ventilation of the North Atlantic Ocean in a global version of the Miami Isopycnal Coordinate Ocean Model (MICOM driven by the daily NCEP/NCAR forcing. Age tracers attached to 29 idealised tracers are also used to estimate the timescales for the water masses’ transports. Our results show that the simulated overturning circulation matches the available observed data for both intensity and variability, and the simulated distribution of CFC-11 concentration in the subtropical North Atlantic Ocean is in good agreement with the observations, particularly above 800 m in depth. We found that the sandwich-like distribution of CFC-11 concentration in the subtropical North Atlantic in both the observations and simulations is mainly caused by subduction from the western and eastern subpolar North Atlantic, but the contribution of the former (56.0% is almost four times larger than that of the latter (15.7%. We demonstrated that the ocean dynamics, instead of the source function, determine the annual and inter-annual variability in both dynamically active tracer (such as water temperature and salinity and passive tracer (such as CFC-11 and idealised tracer concentrations in the deep North Atlantic. The ‘apparent age’ distribution shows that the surface water in the western subpolar North Atlantic takes about 12 yr to reach the Nordic Seas and takes 20 yr from the Nordic Seas to the subtropical deep North Atlantic. The transit-time derived by ‘optimum time lag’ approach shows a 9.3–13.6 yr lag for the signals propagating from the western subpolar North Atlantic to the subtropical North Atlantic, which is generally consistent with that of about 10 yr derived from the ‘apparent age’. The study suggests that geographically defined tracers can be used as

  19. Experiments to Evaluate and Implement Passive Tracer Gas Methods to Measure Ventilation Rates in Homes

    Energy Technology Data Exchange (ETDEWEB)

    Lunden, Melissa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Heredia, Elizabeth [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cohn, Sebastian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dickerhoff, Darryl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Noris, Federico [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Logue, Jennifer [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hotchi, Toshifumi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-10-01

    This report documents experiments performed in three homes to assess the methodology used to determine air exchange rates using passive tracer techniques. The experiments used four different tracer gases emitted simultaneously but implemented with different spatial coverage in the home. Two different tracer gas sampling methods were used. The results characterize the factors of the execution and analysis of the passive tracer technique that affect the uncertainty in the calculated air exchange rates. These factors include uncertainties in tracer gas emission rates, differences in measured concentrations for different tracer gases, temporal and spatial variability of the concentrations, the comparison between different gas sampling methods, and the effect of different ventilation conditions.

  20. Quasars as tracers of cosmic flows

    CERN Document Server

    Modzelewska, J; Bilicki, M; Hryniewicz, K; Krupa, M; Petrogalli, F; Pych, W; Kurcz, A; Udalski, A

    2014-01-01

    Quasars, as the most luminous persistent sources in the Universe, have broad applications for cosmological studies. In particular, they can be employed to directly measure the expansion history of the Universe, similarly to SNe Ia. The advantage of quasars is that they are numerous, cover a broad range of redshifts, up to $z = 7$, and do not show significant evolution of metallicity with redshift. The idea is based on the relation between the time delay of an emission line and the continuum, and the absolute monochromatic luminosity of a quasar. For intermediate redshift quasars, the suitable line is Mg II. Between December 2012 and March 2014, we performed five spectroscopic observations of the QSO CTS C30.10 ($z = 0.900$) using the South African Large Telesope (SALT), supplemented with photometric monitoring, with the aim of determining the variability of the line shape, changes in the total line intensity and in the continuum. We show that the method is very promising.

  1. A tracer test to determine subsurface outflow of a karst catchment along the Lauchert-Graben, Swabian Alb

    Science.gov (United States)

    Knöll, Paul; Scheytt, Traugott

    2017-04-01

    During a severe flood event in 2013 it was hypothesised that a significant amount of flood water from the lower course of the Lauchert infiltrated into the karst system, flowing towards the Danube catchment. The Lauchert, a tributary of the river Danube is a perennial stream in the Swabian Alb, southern Germany. Its catchment is entirely comprised of Upper Jurassic karstified carbonate rocks, slightly dipping south-east. The river mainly flows in the so called Lauchert-Graben except for the lower course. An artificial dye tracer experiment was conducted in August 2016 to examine a connection of the Lauchert and Danube catchment. 4 kg of Uranine were injected into the unsaturated zone of the Lauchert surface catchment, approximately 200 m west of the eastern main fault of the Lauchert-Graben. Close to the injection point the Lauchert is crossing this fault. A total of 7 observation points were monitored, among those the river Lauchert and 6 springs in the Danube valley. 3 of the springs were monitored with field fluorimeters while the other observation points were monitored by regular sampling for 5 days. A tracer breakthrough was detected at 3 springs in the Danube valley, showing a southward flow direction with a maximum transport velocity of 81 m/h. Tracer breakthrough curves were analysed using the CXTFIT code implemented in Stanmod. This experiment proved a preferential hydraulic connection from the Lauchert valley to springs in the Danube valley in the vicinity of the Lauchert-Graben and revealed a flow towards the Danube catchment. The monitored springs in the Danube valley are at least partly fed by groundwater originating in the Lauchert catchment. Augmented flow of flood water through the karst system becomes very likely if an inundation reaches outcropping karst structures flanking the Lauchert flood plain.

  2. Photoelectron spectroscopy of phthalocyanine vapors

    Energy Technology Data Exchange (ETDEWEB)

    Berkowitz, J.

    1979-01-01

    The He(I) photoelectron spectra of several metal phthalocyanines and metal-free phthalocyanine vapor shows that: a sharp peak at 4.99 eV is an artifact due to ionization of atomic He by He(II) radiation; the first phthalocyanine peak (metal-containing or metal-free) occurs at 6.4 eV; and the metal-like d orbitals lie at least 1 to 2 eV deeper, except in the case of Fe. (DLC)

  3. Photovoltaic driven vapor compression cycles

    Science.gov (United States)

    Anand, D. K.

    Since the vast majority of heat pumps, air conditioning and refrigeration equipment employs the vapor compression cycle (VCC), the use of renewable energy represents a significant opportunity. As discussed in this report, it is clear that the use of photovoltaics (PV) to drive the VCC has more potential than any other active solar cooling approach. This potential exists due to improvements in not only the PV cells but VCC machinery and control algorithms. It is estimated that the combined improvements will result in reducing the PV cell requirements by as much as one half.

  4. Photoacoustic Detection of Perfluorocarbon Tracers in Air for Application to Leak Detection in Oil-Filled Cables

    Science.gov (United States)

    Zajarevich, N.; Slezak, V.; Peuriot, A.; Villa, G.; Láttero, A.; Crivicich, R.

    2013-09-01

    The underground oil-filled cable consists of a hollow copper conductor surrounded by oiled paper which acts as electrical insulation. The oil flows along the conductor and diffuses through it to the insulating paper. A lead sheath is used as the outer retaining wall. As the deterioration of this cover may cause a loss of insulation fluid, its detection is very important since this high voltage and power cable is used in cities even under sidewalks. The method of perfluorocarbon vapor tracers, based on the injection and subsequent detection of these volatile chemical substances in the vicinity of the cable, is one of the most promising methods, so far used in combination with gas chromatography and mass spectrometry. In this study, the possibility of detecting two different tracers, and , by means of resonant photoacoustic spectroscopy is studied. The beam from a tunable amplitude-modulated laser goes through an aluminum cell with quarter wave filters at both ends of an open resonator and an electret microphone in its center, attached to the walls. The calibration of the system for either substance diluted in chromatographic air showed a higher sensitivity for , so the experiment was completed checking the behavior of this substance in samples prepared with ambient air in order to analyze the application of the system to field studies.

  5. Radon-222 and beryllium-7 as natural tracer; Radon-222 und Beryllium-7 als natuerliche Tracer

    Energy Technology Data Exchange (ETDEWEB)

    Frank, G.; Steinkopff, T. [Deutscher Wetterdienst, Offenbach (Germany). Radioaktivitaetsueberwachung; Salvamoser, J. [Institut fuer Angewandte Isotopen-, Gas- und Umweltuntersuchungen (IGU), Woerthsee (Germany)

    2016-07-01

    The Global Atmosphere Watch Program (GAW) is intended to analyse worldwide the influence of anthropogenic emissions to the atmosphere. Data are continuously transferred to the ''World Data Centre for Green House Gases'' of the WMO. For the study of atmospheric transports the natural radionuclides Rn-222, Be-7, Pb-210, Pb- 214 and Bi-214 are continuously measured at the Umweltforschungsstation Schneefernerhaus (2650 m) and at the Zugspitze (2962 m) by the Deutscher Wetterdienst (DWD, German Weather Service). The measurements support the classification of atmospheric transport, atmospheric dilution and dispersion models of gaseous and aerosol bond micro pollutants. Results are carried out in combination with meteorological data. It is shown the optimization and effect of a new sampling site for the measurement of Rn-222 activity at the Zugspitze. Results of Rn-222 and Be-7 concentrations are shown in relation to horizontal and vertical dispersion of air masses. The origin of natural Rn-222 and Be-7 are known, therefore both nuclides are well suited for the research of atmospheric transport. Rn-222 is an ideal tracer, because there is no influence by atmospheric processes (chemical processes, wash out effects).

  6. Preliminary Results of 4-D Water Vapor Tomography in the Troposphere Using GPS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Slant-path water vapor amounts (SWV) from a station to all the GPS (Global Positioning System)satellites in view can be estimated by using a ground-based GPS receiver. In this paper, a tomographic method was utilized to retrieve the local horizontal and vertical structure of water vapor over a local GPS receiver network using SWV amounts as observables in the tomography. The method of obtaining SWV using ground-based GPS is described first, and then the theory of tomography using GPS is presented.A water vapor tomography experiment was made using a small GPS network in the Beijing region. The tomographic results were analyzed in two ways: (1) a pure GPS method, i.e., only using GPS observables as input to the tomography; (2) combining GPS observables with vertical constraints or a priori information,which come from average radiosonde measurements over three days. It is shown that the vertical structure of water vapor is well resolved with a priori information. Comparisons of profiles between radiosondes and GPS show that the RMS error of the tomography is about 1-2 mm. It is demonstrated that the tomography can monitor the evolution of tropospheric water vapor in space and time. The vertical resolution of the tomography is tested with layer thicknesses of 600 m, 800 m and 1000 m. Comparisons with radiosondes show that the result from a resolution of 800 m is slightly better than results from the other two resolutions in the experiment. Water vapor amounts recreated from the tomography field agree well with precipitable water vapor (PWV) calculated using GPS delays. Hourly tomographic results are also shown using the resolution of 800 m. Water vapor characteristics under the background of heavy rainfall development are analyzed using these tomographic results. The water vapor spatio-temporal structures derived from the GPS network show a great potential in the investigation of weather disasters.

  7. TRAC, a collaborative computer tool for tracer-test interpretation

    Science.gov (United States)

    Gutierrez, A.; Klinka, T.; Thiéry, D.; Buscarlet, E.; Binet, S.; Jozja, N.; Défarge, C.; Leclerc, B.; Fécamp, C.; Ahumada, Y.; Elsass, J.

    2013-05-01

    Artificial tracer tests are widely used by consulting engineers for demonstrating water circulation, proving the existence of leakage, or estimating groundwater velocity. However, the interpretation of such tests is often very basic, with the result that decision makers and professionals commonly face unreliable results through hasty and empirical interpretation. There is thus an increasing need for a reliable interpretation tool, compatible with the latest operating systems and available in several languages. BRGM, the French Geological Survey, has developed a project together with hydrogeologists from various other organizations to build software assembling several analytical solutions in order to comply with various field contexts. This computer program, called TRAC, is very light and simple, allowing the user to add his own analytical solution if the formula is not yet included. It aims at collaborative improvement by sharing the tool and the solutions. TRAC can be used for interpreting data recovered from a tracer test as well as for simulating the transport of a tracer in the saturated zone (for the time being). Calibration of a site operation is based on considering the hydrodynamic and hydrodispersive features of groundwater flow as well as the amount, nature and injection mode of the artificial tracer. The software is available in French, English and Spanish, and the latest version can be downloaded from the web site http://trac.brgm.fr">http://trac.brgm.fr.

  8. Correlative microscopy of densely labeled projection neurons using neural tracers.

    Science.gov (United States)

    Oberti, Daniele; Kirschmann, Moritz A; Hahnloser, Richard H R

    2010-01-01

    Three-dimensional morphological information about neural microcircuits is of high interest in neuroscience, but acquiring this information remains challenging. A promising new correlative technique for brain imaging is array tomography (Micheva and Smith, 2007), in which series of ultrathin brain sections are treated with fluorescent antibodies against neurotransmitters and synaptic proteins. Treated sections are repeatedly imaged in the fluorescence light microscope (FLM) and then in the electron microscope (EM). We explore a similar correlative imaging technique in which we differentially label distinct populations of projection neurons, the key routers of electrical signals in the brain. In songbirds, projection neurons can easily be labeled using neural tracers, because the vocal control areas are segregated into separate nuclei. We inject tracers into areas afferent and efferent to the main premotor area for vocal production, HVC, to retrogradely and anterogradely label different classes of projection neurons. We optimize tissue preparation protocols to achieve high fluorescence contrast in the FLM and good ultrastructure in the EM (using osmium tetroxide). Although tracer fluorescence is lost during EM preparation, we localize the tracer molecules after fixation and embedding by using fluorescent antibodies against them. We detect signals mainly in somata and dendrites, allowing us to classify synapses within a single ultrathin section as belonging to a particular type of projection neuron. The use of our method will be to provide statistical information about connectivity among different neuron classes, and to elucidate how signals in the brain are processed and routed among different areas.

  9. Correlative microscopy of densely labeled projection neurons using neural tracers

    Directory of Open Access Journals (Sweden)

    Daniele Oberti

    2010-06-01

    Full Text Available Three-dimensional morphological information about neural microcircuits is of high interest in neuroscience, but acquiring this information remains challenging. A promising new correlative technique for brain imaging is array tomography (Micheva and Smith, 2007, in which series of ultrathin brain sections are treated with fluorescent antibodies against neurotransmitters and synaptic proteins. Treated sections are repeatedly imaged in the fluorescence light microscope (FLM and then in the electron microscope (EM. We explore a similar correlative imaging technique in which we differentially label distinct populations of projection neurons, the key routers of electrical signals in the brain. In songbirds, projection neurons can easily be labeled using neural tracers, because the vocal control areas are segregated into separate nuclei. We inject tracers into areas afferent and efferent to the main premotor area for vocal production, HVC, to retrogradely and anterogradely label different classes of projection neurons. We optimize tissue preparation protocols to achieve high fluorescence contrast in the FLM and good ultrastructure in the EM (using osmium tetroxide. Although tracer fluorescence is lost during EM preparation, we localize the tracer molecules after fixation and embedding by using fluorescent antibodies against them. We detect signals mainly in somata and dendrites, allowing us to classify synapses within a single ultrathin section as belonging to a particular type of projection neuron. The use of our method will be to provide statistical information about connectivity among different neuron classes, and to elucidate how signals in the brain are processed and routed among different areas.

  10. Tracer Studies In A Laboratory Beach Subjected To Waves

    Science.gov (United States)

    This work investigated the washout of dissolved nutrients from beaches due to waves by conducting tracer studies in a laboratory beach facility. The effects of waves were studied in the case where the beach was subjected to the tide, and that in which no tidal action was present...

  11. Microfluidics: A Groundbreaking Technology for PET Tracer Production?

    Directory of Open Access Journals (Sweden)

    Björn Wängler

    2013-07-01

    Full Text Available Application of microfluidics to Positron Emission Tomography (PET tracer synthesis has attracted increasing interest within the last decade. The technical advantages of microfluidics, in particular the high surface to volume ratio and resulting fast thermal heating and cooling rates of reagents can lead to reduced reaction times, increased synthesis yields and reduced by-products. In addition automated reaction optimization, reduced consumption of expensive reagents and a path towards a reduced system footprint have been successfully demonstrated. The processing of radioactivity levels required for routine production, use of microfluidic-produced PET tracer doses in preclinical and clinical imaging as well as feasibility studies on autoradiolytic decomposition have all given promising results. However, the number of microfluidic synthesizers utilized for commercial routine production of PET tracers is very limited. This study reviews the state of the art in microfluidic PET tracer synthesis, highlighting critical design aspects, strengths, weaknesses and presenting several characteristics of the diverse PET market space which are thought to have a significant impact on research, development and engineering of microfluidic devices in this field. Furthermore, the topics of batch- and single-dose production, cyclotron to quality control integration as well as centralized versus de-centralized market distribution models are addressed.

  12. Tracer Studies In A Laboratory Beach Subjected To Waves

    Science.gov (United States)

    This work investigated the washout of dissolved nutrients from beaches due to waves by conducting tracer studies in a laboratory beach facility. The effects of waves were studied in the case where the beach was subjected to the tide, and that in which no tidal action was present...

  13. 76 FR 71610 - Market Test of First-Class Tracer

    Science.gov (United States)

    2011-11-18

    ... research and development costs incurred in connection with new product development. Id. Statutory authority... product, First- Class Tracer. This document describes the proposed test, addresses procedural aspects of... a market test beginning on or about December 7, 2011, of an experimental market dominant...

  14. Granulation of Pyrotechnic Tracer Composition R284T

    Science.gov (United States)

    1988-03-01

    Properties of Materials used in Pyrotechnic Compositions (1963). Engineering Design Handbook - Military Pyrotechnic Series Part 3. AMPC 706-187. 4...Ml Cartridge AMPC 706-185 APPLICATION: Main Tracer Charge TM9-1910 Ellern STORAGE: NATO DoD McIntyre Hazards Class (Q/D 1.1 7 Cabbaje & Ewing

  15. Carbon monoxide : A quantitative tracer for fossil fuel CO2?

    NARCIS (Netherlands)

    Gamnitzer, Ulrike; Karstens, Ute; Kromer, Bernd; Neubert, Rolf E. M.; Meijer, Harro A. J.; Schroeder, Hartwig; Levin, Ingeborg

    2006-01-01

    Carbon monoxide (CO), carbon dioxide (CO2), and radiocarbon ((CO2)-C-14) measurements have been made in Heidelberg from 2001 to 2004 in order to determine the regional fossil fuel CO2 component and to investigate the application of CO as a quantitative tracer for fossil fuel CO2 (CO2(foss)). The obs

  16. Diagnostic Implications of the Reactivity of Fluorescence Tracers

    Energy Technology Data Exchange (ETDEWEB)

    Sick, V; Westbrook, C

    2008-07-14

    Measurements of fuel concentration distributions with planar laser induced fluorescence of tracer molecules that are added to a base fuel are commonly used in combustion research and development. It usually is assumed that the tracer concentration follows the parent fuel concentration if physical properties such as those determining evaporation are matched. As an example to address this general issue a computational study of combustion of biacetyl/iso-octane mixtures was performed to investigate how well the concentration of biacetyl represents the concentration of iso-octane. For premixed mixture conditions with flame propagation the spatial concentration profiles of the two species in the flame front are separated by 110 {micro}m at 1 bar and by 11 {micro}m at 10 bar. For practical applications this spatial separation is insignificantly small. However, for conditions that mimic ignition and combustion in diesel and HCCI-like operation the differences in tracer and fuel concentration can be significant, exceeding hundreds of percent. At low initial temperature biacetyl was found to be more stable whereas at higher temperature (>1000K) iso-octane is more stable. Similar findings were obtained for a multi-component fuel comprised of iso-octane, n-heptane, methylcyclohexane, and toluene. It may be assumed that similar differences can exist for other tracer/fuel combinations. Caution has therefore to be applied when interpreting PLIF measurements in homogeneous reaction conditions such as in HCCI engine studies.

  17. Unit vent airflow measurements using a tracer gas technique

    Energy Technology Data Exchange (ETDEWEB)

    Adams, D.G. [Union Electric Company, Fulton, MO (United States); Lagus, P.L. [Lagus Applied Technology, Inc., San Diego, CA (United States); Fleming, K.M. [NCS Corp., Columbus, OH (United States)

    1997-08-01

    An alternative method for assessing flowrates that does not depend on point measurements of air flow velocity is the constant tracer injection technique. In this method one injects a tracer gas at a constant rate into a duct and measures the resulting concentration downstream of the injection point. A simple equation derived from the conservation of mass allows calculation of the flowrate at the point of injection. Flowrate data obtained using both a pitot tube and a flow measuring station were compared with tracer gas flowrate measurements in the unit vent duct at the Callaway Nuclear Station during late 1995 and early 1996. These data are presented and discussed with an eye toward obtaining precise flowrate data for release rate calculations. The advantages and disadvantages of the technique are also described. In those test situations for which many flowrate combinations are required, or in large area ducts, a tracer flowrate determination requires fewer man-hours than does a conventional traverse-based technique and does not require knowledge of the duct area. 6 refs., 10 figs., 6 tabs.

  18. Bridging the gaps in 18F PET tracer development

    Science.gov (United States)

    Campbell, Michael G.; Mercier, Joel; Genicot, Christophe; Gouverneur, Véronique; Hooker, Jacob M.; Ritter, Tobias

    2017-01-01

    As compared to the drug discovery process, the development of new 18F PET tracers lacks a well-established pipeline that advances compounds from academic research to candidacy for (pre)clinical imaging. In order to bridge the gaps between methodological advances and clinical success, we must rethink the development process from training to implementation.

  19. Uptake and transport of positron-emitting tracer in plants

    Energy Technology Data Exchange (ETDEWEB)

    Kume, Tamikazu; Matsuhashi, Shinpei; Shimazu, Masamitsu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment] [and others

    1997-03-01

    The transport of a positron-emitting isotope introduced into a plant was dynamically followed by a special observation apparatus called `Positron-Emitting Tracer Imaging System`. In the system, annihilation {gamma}-rays from the positron emitter are detected with two planer detectors (5 x 6 cm square). The water containing ca. 5 MBq/ml of {sup 18}F was fed to the cut stem of soybean for 2 min and then the images of tracer activity were recorded for 30 - 50 min. When the midrib of a leaf near the petiole was cut just before measurement, the activity in the injured leaf was decreased but detected even at the apex. This result suggests that the damaged leaf recovered the uptake of water through the lamina. Maximum tracer activities in leaves of unirradiated plant were observed within 10 min, whereas those of irradiated plant at 100 Gy were observed after over 25 min. The final activity of irradiated plant after 30 min was lower than that of unirradiated plant. In case of beans, there was a difference in the absorption behavior of the {sup 18}F-labeled water between unirradiated and irradiated samples. These results show that the system is effective to observe the uptake and transportation of water containing positron emitting tracer for the study of damage and recovery functions of plants. (author)

  20. Influence of Soil Moisture on Soil Gas Vapor Concentration for Vapor Intrusion

    OpenAIRE

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    Mathematical models have been widely used in analyzing the effects of various environmental factors in the vapor intrusion process. Soil moisture content is one of the key factors determining the subsurface vapor concentration profile. This manuscript considers the effects of soil moisture profiles on the soil gas vapor concentration away from any surface capping by buildings or pavement. The “open field” soil gas vapor concentration profile is observed to be sensitive to the soil moisture di...

  1. Real-time point-of-care measurement of impaired renal function in a rat acute injury model employing exogenous fluorescent tracer agents

    Science.gov (United States)

    Dorshow, Richard B.; Fitch, Richard M.; Galen, Karen P.; Wojdyla, Jolette K.; Poreddy, Amruta R.; Freskos, John N.; Rajagopalan, Raghavan; Shieh, Jeng-Jong; Demirjian, Sevag G.

    2013-02-01

    Renal function assessment is needed for the detection of acute kidney injury and chronic kidney disease. Glomerular filtration rate (GFR) is now widely accepted as the best indicator of renal function, and current clinical guidelines advocate its use in the staging of kidney disease. The optimum measure of GFR is by the use of exogenous tracer agents. However current clinically employed agents lack sensitivity or are cumbersome to use. An exogenous GFR fluorescent tracer agent, whose elimination rate could be monitored noninvasively through skin would provide a substantial improvement over currently available methods. We developed a series of novel aminopyrazine analogs for use as exogenous fluorescent GFR tracer agents that emit light in the visible region for monitoring GFR noninvasively over skin. In rats, these compounds are eliminated by the kidney with urine recovery greater than 90% of injected dose, are not broken down or metabolized in vivo, are not secreted by the renal tubules, and have clearance values similar to a GFR reference compound, iothalamate. In addition, biological half-life of these compounds measured in rats by noninvasive optical methods correlated with plasma derived methods. In this study, we show that this noninvasive methodology with our novel fluorescent tracer agents can detect impaired renal function. A 5/6th nephrectomy rat model is employed.

  2. Observations of atmospheric water vapor with the SAGE 2 instrument

    Science.gov (United States)

    Larsen, Jack C.; Mccormick, M. P.; Mcmaster, L. R.; Chu, W. P.

    1988-01-01

    The Stratospheric Aerosol and Gas Experiment 2 (SAGE 2) is discussed. The SAGE 2 instrument was a multichannel spectrometer that inferred the vertical distribution of water vapor, aerosols, nitrogen dioxide, and ozone by measuring the extinction of solar radiation at spacecraft sunrise/sunset. At altitudes above 20 km, the SAGE 2 and LIMS (Limb Infrared Monitor of the Stratosphere) data are in close agreement. The discrepancies below this altitude may be attributed to differences in the instruments' field of view and time of data acquisition.

  3. Assessment of Halon-1301 as a groundwater age tracer

    Science.gov (United States)

    Beyer, M.; van der Raaij, R.; Morgenstern, U.; Jackson, B.

    2015-06-01

    Groundwater dating is an important tool to assess groundwater resources in regards to their dynamics, i.e. direction and timescale of groundwater flow and recharge, contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However, ambiguous age interpretations are often faced, due to a limited set of available tracers and their individual restricted application ranges. For more robust groundwater dating multiple tracers need to be applied complementarily (or other characterisation methods need to be used to complement tracer information). It is important that additional, groundwater age tracers are found to ensure robust groundwater dating in future. We have recently suggested that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate, but its behaviour in water and suitability as a groundwater age tracer had not yet been assessed in detail. In this study, we determined Halon-1301 and inferred age information in 17 New Zealand groundwater samples and various modern (river) water samples. The samples were simultaneously analysed for Halon-1301 and SF6, which allowed for identification of issues such as contamination of the water with modern air during sampling. All analysed groundwater sites had also been previously dated with tritium, CFC-12, CFC-11 and SF6, and exhibited mean residence times ranging from modern (close to 0 years) to over 100 years. The investigated groundwater samples ranged from oxic to highly anoxic. All samples with available CFC data were degraded and/or contaminated in one or both of CFC-11 and CFC-12. This allowed us to make a first attempt of assessing the conservativeness of Halon-1301 in water, in terms of presence of local sources and its sensitivity towards degradation, which could affect the suitability of Halon-1301 as groundwater age tracer. Overall we found Halon-1301

  4. Synthesis and characterization of environmentally friendly fluorescent particle tracers

    Science.gov (United States)

    Tauro, Flavia; Porfiri, Maurizio; Rapiti, Emiliano; Grimaldi, Salvatore

    2013-04-01

    Tracers are widely used in experimental fluid mechanics and hydrology to investigate complex flows and water cycle processes. Commonly used tracers include dyes, artificial tracers, naturally occurring isotopes and chemicals, microorganisms, and DNA-based systems. Tracers should be characterized by low detection limits and high accuracy in following water paths and flow structures. For natural studies, tracers are also expected to be nontoxic and with low sorption affinity to natural substrates to minimize losses in the environment. In this context, while isotopes are completely natural, their use in field studies is limited by their ubiquity and, therefore, by the high uncertainty in data processing methodologies. Further, the use of dyes and artificial tracers can be hampered by extremely low detection limits due to dilution in natural streams and microorganisms, while DNA-based system may require physical sampling and time-consuming functionalization and detection procedures. In this work, we present the synthesis and characterization of fluorescent beads incorporating an eco-compatible fluorophore for environmental and laboratory applications. The particles are synthesized from natural beeswax through an inexpensive thermal procedure and can be engineered to present variable densities and diameters. A thorough characterization of their surface morphology at the nanoscale, crystal structure and size, chemical composition, and dye incorporation into the beeswax matrix is described by using a wide array of microscopy techniques. In addition, the particle fluorescence response is studied by performing excitation and emission scans on melted beeswax bead samples. The feasibility of using the synthesized particles in environmental settings is assessed through the design of ad-hoc weathering agent experiments where the beads are exposed to high energy radiation and hot water. Further, a proof of concept test is described to understand the particles' potential as a

  5. Behavior of vapor/plasma within the keyhole and above the workpiece during CO2 laser penetration welding

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, a high-speed camera and an optical emission monitor were used to study the behavior of vapor/plasma during CO2 laser welding of SUS304 stainless steel. Results of optical emission from vapor/plasma show that two characteristic frequency bands exist, 100-500 Hz and 1 500-3 500 Hz. At the same time, the changing images of vapor/plasma and bottom pool also confirm that there are two different fluctuation frequency bands. One of the frequency bands represents the characteristic of vapor/plasma within the keyhole, and it is within 167-500 Hz. Another frequency band is within 1 500-3 500 Hz, and it obviously derives from the shielding gas. Some factors may cause these frequency differences between the keyhole plasma and the shielding gas plasma. One of them is that the vapor/plasma pressure within the keyhole will increase slowly.

  6. Water vapor in the protoplanetary disk of DG Tau

    CERN Document Server

    Podio, L; Codella, C; Cabrit, S; Nisini, B; Dougados, C; Sandell, G; Williams, J P; Testi, L; Thi, W -F; Woitke, P; Meijerink, R; Spaans, M; Aresu, G; Menard, F; Pinte, C

    2013-01-01

    Water is key in the evolution of protoplanetary disks and the formation of comets and icy/water planets. While high excitation water lines originating in the hot inner disk have been detected in several T Tauri stars (TTSs), water vapor from the outer disk, where most of water ice reservoir is stored, was only reported in the closeby TTS TW Hya. We present spectrally resolved Herschel/HIFI observations of the young TTS DG Tau in the ortho- and para- water ground-state transitions at 557, 1113 GHz. The lines show a narrow double-peaked profile, consistent with an origin in the outer disk, and are ~19-26 times brighter than in TW Hya. In contrast, CO and [C II] lines are dominated by emission from the envelope/outflow, which makes H2O lines a unique tracer of the disk of DG Tau. Disk modeling with the thermo-chemical code ProDiMo indicates that the strong UV field, due to the young age and strong accretion of DG Tau, irradiates a disk upper layer at 10-90 AU from the star, heating it up to temperatures of 600 K...

  7. The determination of mass of metabolites with tracers

    Energy Technology Data Exchange (ETDEWEB)

    Katz, J. (Cedars-Sinai Medical Center, Los Angeles, CA (USA))

    1989-08-01

    Application of tracers in vivo for the determination of replacement and mass of bloodborne compounds at steady state is discussed. Theory and methods to determine mass with tracers (total amount of compound-tracee-within the body) for compartmental and noncompartmental systems are presented, and their limitations examined. Methods to derive mass from the specific activity curves after bolus injection or infusion of tracer are described using graphic procedures or by equations using the parameters of exponential curves. The relationship between assumed models and the interpretation of tracer data is examined. The determination of both replacement (appearance, which equals utilization at steady state) and mass of most compounds present in both extracellular and intracellular fluids (such as lactate and amino acids) requires the application of the A-V mode for tracer administration and sampling of blood. Recycling of carbon affects the determination of mass with {sup 14}C. Estimates of true mass are provided with tritium-labeled compounds, even when tritium loss is by exchange with protons or through futile cycling. Estimates of the amount (body mass) of lactate, alanine, glutamate, and proline obtained with tritium-labeled compounds are presented. Most of these masses are intracellular. The concentration of lactate in tissues equals or is greater, and that of amino acids much greater than that in plasma. Hence, the so-called distribution space for these compounds, calculated conventionally by dividing mass by plasma concentration, would appear to be equal to or greater than the body water of lactate, and several liters per kilogram for amino acids.

  8. Dynamics of ellipsoidal tracers in swimming algal suspensions

    Science.gov (United States)

    Yang, Ou; Peng, Yi; Liu, Zhengyang; Tang, Chao; Xu, Xinliang; Cheng, Xiang

    2016-10-01

    Enhanced diffusion of passive tracers immersed in active fluids is a universal feature of active fluids and has been extensively studied in recent years. Similar to microrheology for equilibrium complex fluids, the unusual enhanced particle dynamics reveal intrinsic properties of active fluids. Nevertheless, previous studies have shown that the translational dynamics of spherical tracers are qualitatively similar, independent of whether active particles are pushers or pullers—the two fundamental classes of active fluids. Is it possible to distinguish pushers from pullers by simply imaging the dynamics of passive tracers? Here, we investigated the diffusion of isolated ellipsoids in algal C. reinhardtii suspensions—a model for puller-type active fluids. In combination with our previous results on pusher-type E. coli suspensions [Peng et al., Phys. Rev. Lett. 116, 068303 (2016), 10.1103/PhysRevLett.116.068303], we showed that the dynamics of asymmetric tracers show a profound difference in pushers and pullers due to their rotational degree of freedom. Although the laboratory-frame translation and rotation of ellipsoids are enhanced in both pushers and pullers, similar to spherical tracers, the anisotropic diffusion in the body frame of ellipsoids shows opposite trends in the two classes of active fluids. An ellipsoid diffuses fastest along its major axis when immersed in pullers, whereas it diffuses slowest along the major axis in pushers. This striking difference can be qualitatively explained using a simple hydrodynamic model. In addition, our study on algal suspensions reveals that the influence of the near-field advection of algal swimming flows on the translation and rotation of ellipsoids shows different ranges and strengths. Our work provides not only new insights into universal organizing principles of active fluids, but also a convenient tool for detecting the class of active particles.

  9. A Lagrangian particle method with remeshing for tracer transport on the sphere

    Science.gov (United States)

    Bosler, Peter A.; Kent, James; Krasny, Robert; Jablonowski, Christiane

    2017-07-01

    A Lagrangian particle method (called LPM) based on the flow map is presented for tracer transport on the sphere. The particles carry tracer values and are located at the centers and vertices of triangular Lagrangian panels. Remeshing is applied to control particle disorder and two schemes are compared, one using direct tracer interpolation and another using inverse flow map interpolation with sampling of the initial tracer density. Test cases include a moving-vortices flow and reversing-deformational flow with both zero and nonzero divergence, as well as smooth and discontinuous tracers. We examine the accuracy of the computed tracer density and tracer integral, and preservation of nonlinear correlation in a pair of tracers. We compare results obtained using LPM and the Lin-Rood finite-volume scheme. An adaptive particle/panel refinement scheme is demonstrated.

  10. Technology update: bronchoscopic thermal vapor ablation for managing severe emphysema

    Directory of Open Access Journals (Sweden)

    Gompelmann D

    2014-09-01

    Full Text Available Daniela Gompelmann,1,2 Ralf Eberhardt,1,2 Felix JF Herth1,21Pneumology and Critical Care Medicine, Thoraxklinik at University of Heidelberg, 2German Center for Lung Research, Heidelberg, GermanyAbstract: Bronchoscopic thermal vapor ablation (BTVA is an endoscopic lung volume reduction therapy that presents an effective treatment approach in patients with severe upper lobe-predominant emphysema. By instillation of heated water vapor, an inflammatory reaction is induced, leading to fibrosis and scarring of the lung parenchyma, resulting in lobar volume reduction. Clinical single-arm trials demonstrated great outcomes, with significant improvement of lung function, exercise capacity, and quality of life. As the BTVA-induced local inflammatory response that seems to be essential for the desired lobar volume reduction can be associated with transient clinical worsening, strict monitoring of the patients is required. In future, the balance between efficacy and safety will constitute a major challenge. This review summarizes the BTVA procedure, the mechanism of action, and the results of the clinical trials, including the efficacy and safety data.Keywords: emphysema, bronchoscopy, bronchoscopic thermal vapor ablation

  11. Program plan for the resolution of tank vapor issues

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, J.W.; Huckaby, J.L.

    1994-05-01

    Since 1987, workers at the Hanford Site waste tank farms in Richland, Washington, have reported strong odors emanating from the large, underground high-level radioactive waste storage tanks. Some of these workers have complained of symptoms (e.g., headaches, nausea) related to the odors. In 1992, the U.S. Department of Energy, which manages the Hanford Site, and Westinghouse Hanford Company determined that the vapor emissions coming from the tanks had not been adequately characterized and represented a potential health risk to workers in the immediate vicinity of the tanks. At that time, workers in certain areas of the tank farms were required to use full-face, supplied-breathing-air masks to reduce their exposure to the fugitive emissions. While use of supplied breathing air reduced the health risks associated with the fugitive emissions, it introduced other health and safety risks (e.g., reduced field of vision, air-line tripping hazards, and heat stress). In 1992, an aggressive program was established to assure proper worker protection while reducing the use of supplied breathing air. This program focuses on characterization of vapors inside the tanks and industrial hygiene monitoring in the tank farms. If chemical filtration systems for mitigation of fugitive emissions are deemed necessary, the program will also oversee their design and installation. This document presents the plans for and approach to resolving the Hanford Site high-level waste tank vapor concerns. It is sponsored by the Department of Energy Office of Environmental Restoration and Waste Management.

  12. Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges

    Directory of Open Access Journals (Sweden)

    Dora M. Paolucci

    2011-03-01

    Full Text Available A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index and sensor response are discussed.

  13. Rapid transport from the surface to wells in fractured rock: a unique infiltration tracer experiment.

    Science.gov (United States)

    Levison, Jana K; Novakowski, Kent S

    2012-04-01

    A unique infiltration tracer experiment was performed whereby a fluorescent dye was applied to the land surface in an agricultural field, near Perth, Ontario, Canada, to simulate the transport of solutes to two pumped monitoring wells drilled into the granitic gneiss aquifer. This experiment, interpreted using the discrete-fracture capability of the numerical model HydroGeoSphere, showed that solute transport from the surface through thin soil (less than 2m) to wells in fractured bedrock can be extremely rapid (on the order of hours). Also, it was demonstrated that maximum concentrations of contaminants originating from the ground surface will not necessarily be the highest in the shallow aquifer horizon. These are important considerations for both private and government-owned drinking water systems that draw water from shallow fractured bedrock aquifers. This research illustrates the extreme importance of protecting drinking water at the source.

  14. A field measurement perspective on the current and future use of carbonyl sulphide as a carbon cycle tracer

    Science.gov (United States)

    Maseyk, Kadmiel; Sun, Wu; Lett, Celine; Juarez, Sabrina; Seibt, Ulli

    2015-04-01

    Carbonyl sulphide (COS) is gaining increasing traction as a tracer to constrain gross terrestrial biosphere-atmosphere CO2 fluxes, due to the close coupling between photosynthesis and COS uptake by plants. Results from laboratory, field and atmospheric measurements, combined with modeling analyses, have all confirmed the potential of COS, but as with any new approach, many details still remain to be resolved. Drawing on results from our field campaigns that include component (branch and soil) and ecosystem COS flux measurements in a range of environments, I will provide a view on what we have learned about using COS as a carbon cycle tracer. These measurements support the view that ecosystem COS fluxes are typically dominated by canopy uptake, and have provided insight into carbon cycle processes not available from CO2 measurements alone. They have also provided some interesting surprises that suggest COS data may also provide information on other biogeochemical and plant processes such as phenology. Our results support the addition of COS to our measurement arsenal to improve our understanding and monitoring of the terrestrial biosphere, but moving forward will require addressing some key uncertainties. These include the role of the soil and the variation in the leaf-level COS to CO2 uptake ratio in different environments. Combining COS with stable isotope tracers, particularly CO2, can provide a powerful way with which to both improve our understanding of COS biogeochemistry and constrain our estimates of terrestrial CO2 fluxes.

  15. Impact of typhoons on the UTLS ozone and water vapor distribution within the Asian summer monsoon anticyclone during the SWOP campaign in Lhasa 2013

    Science.gov (United States)

    Li, Dan; Vogel, Bärbel; Bian, Jianchun; Müller, Rolf

    2016-04-01

    During the sounding water vapor, ozone, and particle (SWOP) campaign during the Asian Summer Monsoon (ASM) organized by the Institute of Atmospheric Physics, Chinese Academy of Sciences, ozone and water vapor profiles were measured by balloon-borne sensors in Lhasa (29.66°N, 91.14°E, elevation 3,650 m), China in August 2013. Totally, 23 soundings were launched, half of which show some deviations from the typical relationship between ozone and water vapor in the tracer-tracer correlation in the upper troposphere and lower stratosphere (UTLS). 20-day backward trajectories of each sounding were calculated using the trajectory module of the Chemical Lagrangian Model of the Stratosphere (CLaMS) to analyse these deviations. Our results demonstrate that during this period three typhoons (Jebi, Utor, and Trami) occurred over the Northwest Pacific Ocean, which have impacts on the vertical structure of ozone and water vapor by transporting the maritime airmasses from the boundary layer. These airmasses with poor ozone were transported to the UTLS by the strong uplift associated with the typhoons, and then entered the ASM anticyclone. Thereafter, air parcels arrived at the observation site through two main pathways: first rotational subsidence, during which air parcels decend slowly along a circle following the anticyclone flow with a timescale of one week, and second direct horizontal transport from the location of the typhoon to the station, where air parcels are transported directly towards the station within approximately three days.

  16. Vapor Pressures of Several Commercially Used Alkanolamines

    NARCIS (Netherlands)

    Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

    2011-01-01

    For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine, N,N-diethylethano

  17. Boron carbide whiskers produced by vapor deposition

    Science.gov (United States)

    1965-01-01

    Boron carbide whiskers have an excellent combination of properties for use as a reinforcement material. They are produced by vaporizing boron carbide powder and condensing the vapors on a substrate. Certain catalysts promote the growth rate and size of the whiskers.

  18. Water Vapor Forecasting for Chilean Sites

    Science.gov (United States)

    Marín, Julio C.; Cuevas, O.; Pozo, D.; Curé, M.

    2017-09-01

    "A number of observatories in Chile operate in the infrared region of the electromagnetic spectrum. Therefore, it is very important to them to accurately know the water vapor content of the atmosphere for a better observational planning. This talk provides an overview of the methods used to forecast water vapor over astronomical sites in Chile using observations and atmospheric numerical modeling."

  19. Can a drawover vaporizer be a pushover?

    Science.gov (United States)

    Taylor, J C; Restall, J

    1994-10-01

    Bench testing was carried out to establish whether the vapour output from an OMV50 vaporizer, as used in the Triservice apparatus, differs according to whether the carrier gas is either drawn or pushed through the vaporizer. Results show that the differences in output concentration between the two modes were clinically insignificant.

  20. Soil vapor extraction with dewatering

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, N.R. [Univ. of Waterloo, Ontario (Canada)

    1996-08-01

    The physical treatment technology of soil vapor extraction (SVE) is reliable, safe, robust, and able to remove significant amounts of mass at a relatively low cost. SVE combined with a pump-and-treat system to create a dewatered zone has the opportunity to remove more mass with the added cost of treating the extracted groundwater. Various limiting processes result in a significant reduction in the overall mass removal rates from a SVE system in porous media. Only pilot scale, limited duration SVE tests conducted in low permeability media have been reported in the literature. It is expected that the presence of a fracture network in low permeability media will add another complexity to the limiting conditions surrounding the SVE technology. 20 refs., 4 figs.

  1. Engineering vapor-deposited polyimides

    Science.gov (United States)

    Tsai, Feng-Yu

    The vapor deposition polymerization (VDP) of PMDA-ODA polyimide was studied parametrically to produce microcapsules and thin films with desirable properties and quality for the Inertial Confinement Fusion (ICF) experiments. The mechanical properties and gas permeability were determined at temperatures from 10 to 573 K. The VDP polyimide possessed distinct properties including lower gas permeability and stronger tensile properties from those of solution-cast Kapton, which were attributed to the presence of cross-linking. Processing parameters determining the properties of the VDP polyimide were identified: (1) utilizing air instead of nitrogen as the atmosphere of imidization increased the permeability by 140%, lowered the activation energy for permeation, and reduced the tensile strength by 30% without affecting the Young's modulus; (2) imidizing at faster heating rates increased the permeability by up to 50% and reduced the activation energy for permeation with 50% lowered tensile strength and impervious Young's modulus; (3) bi-axial stretching increased the permeability by up to three orders of magnitude. Analyses via IR spectroscopy, X-ray diffraction, and density measurement revealed that the effects of the processing parameters were results of the modifications in the crystallinity and molecular weight. The VDP polyimide underwent minor degradation in the tensile strength and elongation at break with unaffected Young's modulus and permeability upon absorbing 120 MGy of beta-radiation. Substituting a fluorinated dianhydride monomer, 6FDA, for PMDA in the optimized VDP process yielded 6FDA-ODA polyimide microcapsules and films with 50-fold increased permeability and comparable mechanical properties. The results of this study enable the production of polyimide microcapsules that will greatly facilitate the ICF experiments, and will broaden the applications of vapor-deposited polyimides in other technology fields.

  2. Vapor-barrier Vacuum Isolation System

    Science.gov (United States)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

    2014-01-01

    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  3. [Study on large-scale regional laser detection methods for water vapor concentration].

    Science.gov (United States)

    He, Ying; Zhang, Yu-Jun; Wang, Li-Ming; You, Kun; Zhou, Yi; Sun, Xiao-Min; Liu, Zhen-Min

    2013-03-01

    Water vapor is an important meteorological parameter in the atmosphere, TDLAS direct absorption technology combined with open-path monitoring was used in order to achieve large-scale regional atmospheric water vapor concentration detection with high sensitivity, high accuracy and fast response, and to correct the remote sensing data. The large-scale regional laser detection system for water vapor was designed and the absorption line of water vapor molecules near 1.27 microm was chosen as the goal line. The system performance was verified in conjunction with a multiple reflection cell, that the system limit sensitivity was 14.803 mmol.mol-1 in optical path of 40 m. The continuous field experiment in 1,420 m optical path at the Yucheng Integrated Experimental Station, CAS was completed with this system which worked stably. Then the measured data was compared with the data of a gas analyzer LI-7500 in eddy correlation observation system at the same site, and the data consistency was good. A new method for water vapor concentration monitoring in the complex field of non-uniform underlying surface was provided.

  4. Quantification of tracer plume transport parameters in 2D saturated porous media by cross-borehole ERT imaging

    Science.gov (United States)

    Lekmine, G.; Auradou, H.; Pessel, M.; Rayner, J. L.

    2017-04-01

    Cross-borehole ERT imaging was tested to quantify the average velocity and transport parameters of tracer plumes in saturated porous media. Seven tracer tests were performed at different flow rates and monitored by either a vertical or horizontal dipole-dipole ERT sequence. These sequences were tested to reconstruct the shape and temporally follow the spread of the tracer plumes through a background regularization procedure. Data sets were inverted with the same inversion parameters and 2D model sections of resistivity ratios were converted to tracer concentrations. Both array types provided an accurate estimation of the average pore velocity vz. The total mass Mtot recovered was always overestimated by the horizontal dipole-dipole and underestimated by the vertical dipole-dipole. The vertical dipole-dipole was however reliable to quantify the longitudinal dispersivity λz, while the horizontal dipole-dipole returned better estimation for the transverse component λx. λ and Mtot were mainly influenced by the 2D distribution of the cumulated electrical sensitivity and the Shadow Effects induced by the third dimension. The size reduction of the edge of the plume was also related to the inability of the inversion process to reconstruct sharp resistivity contrasts at the interface. Smoothing was counterbalanced by a non-realistic rise of the ERT concentrations around the centre of mass returning overpredicted total masses. A sensitivity analysis on the cementation factor m and the porosity ϕ demonstrated that a change in one of these parameters by 8% involved non negligible variations by 30 and 40% of the dispersion coefficients and mass recovery.

  5. Radiocarbon as a Reactive Tracer for Tracking Permanent CO2 Storage in Basaltic Rocks

    Energy Technology Data Exchange (ETDEWEB)

    Matter, Juerg [Columbia Univ., New York, NY (United States); Stute, Martin [Columbia Univ., New York, NY (United States); Schlosser, Peter [Columbia Univ., New York, NY (United States); Broecker, Wallace [Columbia Univ., New York, NY (United States)

    2015-09-30

    In view of concerns about the long-term integrity and containment of CO2 storage in geologic reservoirs, many efforts have been made to improve the monitoring, verification and accounting methods for geologically stored CO2. Our project aimed to demonstrate that carbon-14 (14C) could be used as a reactive tracer to monitor geochemical reactions and evaluate the extent of mineral trapping of CO2 in basaltic rocks. The capacity of a storage reservoir for mineral trapping of CO2 is largely a function of host rock composition. Mineral carbonation involves combining CO2 with divalent cations including Ca2+, Mg2+ and Fe2+. The most abundant geological sources for these cations are basaltic rocks. Based on initial storage capacity estimates, we know that basalts have the necessary capacity to store million to billion tons of CO2 via in situ mineral carbonation. However, little is known about CO2-fluid-rock reactions occurring in a basaltic storage reservoir during and post-CO2 injection. None of the common monitoring and verification techniques have been able to provide a surveying tool for mineral trapping. The most direct method for quantitative monitoring and accounting involves the tagging of the injected CO2 with 14C because 14C is not present in deep geologic reservoirs prior to injection. Accordingly, we conducted two CO2 injection tests at the CarbFix pilot injection site in Iceland to study the feasibility of 14C as a reactive tracer for monitoring CO2-fluid-rock reactions and CO2 mineralization. Our newly developed monitoring techniques, using 14C as a reactive tracer, have been successfully demonstrated. For the first time, permanent and safe disposal of CO2 as environmentally benign carbonate minerals in basaltic rocks could be shown. Over 95% of the injected CO2 at the Carb

  6. Assessment of Halon-1301 as a groundwater age tracer

    Directory of Open Access Journals (Sweden)

    M. Beyer

    2015-01-01

    Full Text Available Groundwater dating is an important tool to assess groundwater resources in regards to their dynamics, i.e. direction and time scale of groundwater flow and recharge, to assess contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However, ambiguous age interpretations are often faced, due to a limited set of available tracers and their individual restricted application ranges. For more robust groundwater dating multiple tracers need to be applied complementarily and it is vital that additional, groundwater age tracers are found to ensure robust groundwater dating in future. We recently suggested that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate, but its behaviour in water and suitability as a groundwater age tracer had not yet been assessed in detail. In this study, we determine Halon-1301 and infer age information in 17 New Zealand groundwaters and various modern (river water samples. The samples are simultaneously analysed for Halon-1301 and SF6, which allows identification of issues such as contamination of the water with modern air during sampling. Water at all analysed groundwater sites have also been previously dated with tritium, CFC-12, CFC-11 and SF6, and exhibit mean residence times ranging from modern (close to 0 years to over 100 years. The investigated groundwater ranged from oxic to highly anoxic, and some showed evidence of CFC contamination or degradation. This allowed us to make a first attempt of assessing the conservativeness of Halon-1301 in water, in terms of presence of local sources and its sensitivity towards degradation etc., which could affect the suitability of Halon-1301 as groundwater age tracer. Overall we found Halon-1301 reliably inferred the mean residence time of groundwater recharged between 1980 and 2014. Where direct age comparison

  7. HANFORD CHEMICAL VAPORS WORKER CONCERNS & EXPOSURE EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON, T.J.

    2006-12-20

    Chemical vapor emissions from underground hazardous waste storage tanks on the Hanford site in eastern Washington State are a potential concern because workers enter the tank farms on a regular basis for waste retrievals, equipment maintenance, and surveillance. Tank farm contractors are in the process of retrieving all remaining waste from aging single-shell tanks, some of which date to World War II, and transferring it to newer double-shell tanks. During the waste retrieval process, tank farm workers are potentially exposed to fugitive chemical vapors that can escape from tank headspaces and other emission points. The tanks are known to hold more than 1,500 different species of chemicals, in addition to radionuclides. Exposure assessments have fully characterized the hazards from chemical vapors in half of the tank farms. Extensive sampling and analysis has been done to characterize the chemical properties of hazardous waste and to evaluate potential health hazards of vapors at the ground surface, where workers perform maintenance and waste transfer activities. Worker concerns. risk communication, and exposure assessment are discussed, including evaluation of the potential hazards of complex mixtures of chemical vapors. Concentrations of vapors above occupational exposure limits-(OEL) were detected only at exhaust stacks and passive breather filter outlets. Beyond five feet from the sources, vapors disperse rapidly. No vapors have been measured above 50% of their OELs more than five feet from the source. Vapor controls are focused on limited hazard zones around sources. Further evaluations of vapors include analysis of routes of exposure and thorough analysis of nuisance odors.

  8. Microbial growth with vapor-phase substrate

    Energy Technology Data Exchange (ETDEWEB)

    Hanzel, Joanna; Thullner, Martin; Harms, Hauke [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany); Wick, Lukas Y., E-mail: lukas.wick@ufz.de [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany)

    2011-04-15

    Limited information exists on influences of the diffusive transport of volatile organic contaminants (VOC) on bacterial activity in the unsaturated zone of the terrestrial subsurface. Diffusion of VOC in the vapor-phase is much more efficient than in water and results in effective VOC transport and high bioavailability despite restricted mobility of bacteria in the vadose zone. Since many bacteria tend to accumulate at solid-water, solid-air and air-water interfaces, such phase boundaries are of a special interest for VOC-biodegradation. In an attempt to evaluate microbial activity toward air-borne substrates, this study investigated the spatio-temporal interplay between growth of Pseudomonas putida (NAH7) on vapor-phase naphthalene (NAPH) and its repercussion on vapor-phase NAPH concentrations. Our data demonstrate that growth rates of strain PpG7 were inversely correlated to the distance from the source of vapor-phase NAPH. Despite the high gas phase diffusivity of NAPH, microbial growth was absent at distances above 5 cm from the source when sufficient biomass was located in between. This indicates a high efficiency of suspended bacteria to acquire vapor-phase compounds and influence headspace concentration gradients at the centimeter-scale. It further suggests a crucial role of microorganisms as biofilters for gas-phase VOC emanating from contaminated groundwater or soil. - Research highlights: > Suspended bacteria have a high efficiency to degrade vapor-phase naphthalene. > Bacteria influence NAPH vapor-phase concentration gradients at centimeter-scale. > Microbial growth on vapor-phase naphthalene is inversely correlated to its source. > Bacteria are good biofilters for gas-phase NAPH emanating from contaminated sites. - Suspended bacteria have a high efficiency to degrade vapor-phase naphthalene and effectively influence vapor-phase naphthalene concentration gradients at the centimeter scale.

  9. Use of /sup 75/Se tracer and autoradiographic techniques in the study of schistosomiasis

    Energy Technology Data Exchange (ETDEWEB)

    Chandiwana, S.K. (New York State Veterinary Coll., Ithaca, NY (USA))

    1988-12-01

    The paper provides an overview of recent studies on the use of /sup 75/Se to tag larval schistosomes and to monitor their migration and distribution patterns in naive mice and those previously exposed to cercariae. The principles and techniques of radioassay and autoradiography in studying various aspects of /sup 75/Se-labelled larval schistosomes are described. The main shortcoming of radioassay in monitoring location and movement of labelled schistosomula is that some of the label dissociates from the schistosomula and accumulates in host tissues, notably the liver. Dissociated label is indistinguishable from schistosomula-bound label making monitoring of parasite migration extremely difficult. This difficulty is overcome by compressed tissue autoradiography where labelled schistosomula can be seen as reduced silver foci on an autoradiographic film, whereas dissociated label is too diffusely distributed to produce such reduced silver foci. Furthermore, using autoradiography, quantitative information on parasite migration in normal and immunized laboratory animals can be obtained that would be impossible using traditional recovery techniques. In addition to using /sup 75/Se tracer in migration studies, the radio-isotope has potential for elucidating various aspects of schistosome transmission ecology and snail population dynamics in natural waters. (author).

  10. Identification and characterization of conservative organic tracers for use as hydrologic tracers for the Yucca Mountain Site Characterization Study; Progress report, June 1--December 31, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Stetzenbach, K.J.

    1990-12-31

    Ground water tracers are solutes dissolved in or carried by ground water to delineate flow pathways. Tracers provide information on direction and speed of water movement and that of contaminants that might be conveyed by the water. Tracers can also be used to measure effective porosity, hydraulic conductivity, dispersivity and solute distribution coefficients. For most applications tracers should be conservative, that is, move at the same rate as the water and not sorb to aquifer materials. Tracers must have a number of properties to be functional. Regardless of the desired properties, the chemical and physical behavior of a tracer in ground water and the porous medium under study must be understood. Good estimates of tracer behavior can be obtained from laboratory studies. Studies in this proposal will address tracer properties with analytical method development, static sorption and degradation studies and column transport studies, Mutagenicity tests will be performed on promising candidates. The tracers that will be used for these experiments are fluorinated organic acids and other organic compounds that have the chemical and biological stability necessary to be effective in the Yucca Mountain environment. Special emphasis will be placed on compounds that fluoresce or have very large ultraviolet absorption coefficients for very high analytical sensitivity.

  11. Application of enriched stable isotopes as tracers in biological systems

    DEFF Research Database (Denmark)

    Stürup, Stefan; Hansen, Helle Rüsz; Gammelgaard, Bente

    2008-01-01

    The application of enriched stable isotopes of minerals and trace elements as tracers in biological systems is a rapidly growing research field that benefits from the many new developments in inorganic mass spectrometric instrumentation, primarily within inductively coupled plasma mass spectrometry...... (ICP-MS) instrumentation, such as reaction/collision cell ICP-MS and multicollector ICP-MS with improved isotope ratio measurement and interference removal capabilities. Adaptation and refinement of radioisotope tracer experiment methodologies for enriched stable isotope experiments......, and the development of new methodologies coupled with more advanced compartmental and mathematical models for the distribution of elements in living organisms has enabled a broader use of enriched stable isotope experiments in the biological sciences. This review discusses the current and future uses of enriched...

  12. In-situ fracture mapping using geotomography and brine tracers

    Energy Technology Data Exchange (ETDEWEB)

    Deadrick, F.J.; Ramirez, A.L.; Lytle, R.J.

    1981-01-01

    The Lawrence Livermore National Laboratory is currently assessing the capabilities of high resolution geophysical methods to characterize geologic sites for the disposal of high level nuclear waste. A successful experiment has recently been performed in which salt water tracers and high frequency electromagnetic waves were utilized to map rock mass fracture zones in-situ. Multiple cross-borehole EM transmissions were used to generate a tomographic image of the fractured rock region between two boreholes. The tomographs obtained correlate well with conventional wireline geophysical logs which can be used to infer the location of fractured zones in the rock mass. This indirect data suggests that the geotomography and brine tracer technique may have merit in mapping fractured zones between boreholes.

  13. FormTracer - A Mathematica Tracing Package Using FORM

    CERN Document Server

    Cyrol, Anton K; Strodthoff, Nils

    2016-01-01

    We present FormTracer, a high-performance, general purpose, easy-to-use Mathematica tracing package which uses FORM. It supports arbitrary space and spinor dimensions as well as an arbitrary number of simple compact Lie groups. While keeping the usability of the Mathematica interface, it relies on the efficiency of FORM. An additional performance gain is achieved by a decomposition algorithm that avoids redundant traces in the product tensors spaces. FormTracer supports a wide range of syntaxes which endows it with a high flexibility. Mathematica notebooks that automatically install the package and guide the user through performing standard traces in space-time, spinor and gauge-group spaces are provided.

  14. A historical perspective on radioisotopic tracers in metabolism and biochemistry.

    Science.gov (United States)

    Lappin, Graham

    2015-01-01

    Radioisotopes are used routinely in the modern laboratory to trace and quantify a myriad of biochemical processes. The technique has a captivating history peppered with groundbreaking science and with more than its share of Nobel Prizes. The discovery of radioactivity at the end of the 19th century paved the way to understanding atomic structure and quickly led to the use of radioisotopes to trace the fate of molecules as they flowed through complex organic life. The 1940s saw the first radiotracer studies using homemade instrumentation and analytical techniques such as paper chromatography. This article follows the history of radioisotopic tracers from meager beginnings, through to the most recent applications. The author hopes that those researchers involved in radioisotopic tracer studies today will pause to remember the origins of the technique and those who pioneered this fascinating science.

  15. A Galaxy-Halo Model for Multiple Cosmological Tracers

    CERN Document Server

    Bull, Philip

    2016-01-01

    The information extracted from large galaxy surveys with the likes of DES, DESI, Euclid, LSST, SKA, and WFIRST will be greatly enhanced if the resultant galaxy catalogues can be cross-correlated with one another. Predicting the nature of the information gain, and developing the tools to realise it, depends on establishing a consistent model of how the galaxies detected by each survey trace the same underlying matter distribution. Existing analytic methods, such as halo occupation distribution (HOD) modelling, are not well-suited for this task, and can suffer from ambiguities and tuning issues when applied to multiple tracers. We construct a simple alternative that provides a common model for the connection between galaxies and dark matter halos across a wide range of wavelengths (and thus tracer populations). This is based on a chain of parametrised statistical distributions that model the connection between (a) halo mass and bulk physical properties of galaxies, such as star-formation rate; and (b) those sam...

  16. ARAC results from phase II of the European tracer experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pace, J.C.; Nasstrom, J.S.

    1997-07-01

    A comparison is provided of the results of calculations by the Atmospheric Release Advisory Capability (ARAC) during two phases of the European Tracer Experiment (ETEX). In phase I of ETEX, participants generated predictions in real time of the concentration of inert tracer gases released from a site in Western France. Each participating group based their predictions on the meteorological data they had available. In phase II, all participants were required to recalculate predictions based on the same meteorological data, which was generated and supplied by the European Centre for Medium- Range Weather Forecasts (ECMWF). ARAC used ECMWF data and also made additional changes to its model configuration,, with the result that ARAC`s accuracy during phase II was much better than for phase I. Experiments described in this paper examine the effect of each of these changes, and show that each change contributed to the improvement.

  17. Artificial sweeteners as potential tracers of municipal landfill leachate.

    Science.gov (United States)

    Roy, James W; Van Stempvoort, Dale R; Bickerton, Greg

    2014-01-01

    Artificial sweeteners are gaining acceptance as tracers of human wastewater in the environment. The 3 artificial sweeteners analyzed in this study were detected in leachate or leachate-impacted groundwater at levels comparable to those of untreated wastewater at 14 of 15 municipal landfill sites tested, including several closed for >50 years. Saccharin was the dominant sweetener in old (pre-1990) landfills, while newer landfills were dominated by saccharin and acesulfame (introduced 2 decades ago; dominant in wastewater). Cyclamate was also detected, but less frequently. A case study at one site illustrates the use of artificial sweeteners to identify a landfill-impacted groundwater plume discharging to a stream. The study results suggest that artificial sweeteners can be useful tracers for current and legacy landfill contamination, with relative abundances of the sweeteners potentially providing diagnostic ability to distinguish different landfills or landfill cells, including crude age-dating, and to distinguish landfill and wastewater sources.

  18. Tracer Methods for Characterizing Fracture Creation in Engineered Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Peter [Energy & Geoscience Institute at the University of Utah, Salt Lake City, UT (United States); Harris, Joel [Univ. of Utah, Salt Lake City, UT (United States)

    2014-05-08

    The aim of this proposal is to develop, through novel high-temperature-tracing approaches, three technologies for characterizing fracture creation within Engineered Geothermal Systems (EGS). The objective of a first task is to identify, develop and demonstrate adsorbing tracers for characterizing interwell reservoir-rock surface areas and fracture spacing. The objective of a second task is to develop and demonstrate a methodology for measuring fracture surface areas adjacent to single wells. The objective of a third task is to design, fabricate and test an instrument that makes use of tracers for measuring fluid flow between newly created fractures and wellbores. In one method of deployment, it will be used to identify qualitatively which fractures were activated during a hydraulic stimulation experiment. In a second method of deployment, it will serve to measure quantitatively the rate of fluid flowing from one or more activated fracture during a production test following a hydraulic stimulation.

  19. Evaluation of anthropogenic secondary organic aerosol tracers from aromatic hydrocarbons

    Science.gov (United States)

    Al-Naiema, Ibrahim M.; Stone, Elizabeth A.

    2017-02-01

    Products of secondary organic aerosol (SOA) from aromatic volatile organic compounds (VOCs) - 2,3-dihydroxy-4-oxopentanoic acid, dicarboxylic acids, nitromonoaromatics, and furandiones - were evaluated for their potential to serve as anthropogenic SOA tracers with respect to their (1) ambient concentrations and detectability in PM2.5 in Iowa City, IA, USA; (2) gas-particle partitioning behaviour; and (3) source specificity by way of correlations with primary and secondary source tracers and literature review. A widely used tracer for toluene-derived SOA, 2,3-dihydroxy-4-oxopentanoic acid was only detected in the particle phase (Fp = 1) at low but consistently measurable ambient concentrations (averaging 0.3 ng m-3). Four aromatic dicarboxylic acids were detected at relatively higher concentrations (9.1-34.5 ng m-3), of which phthalic acid was the most abundant. Phthalic acid had a low particle-phase fraction (Fp = 0.26) likely due to quantitation interferences from phthalic anhydride, while 4-methylphthalic acid was predominantly in the particle phase (Fp = 0.82). Phthalic acid and 4-methylphthalic acid were both highly correlated with 2,3-dihydroxy-4-oxopentanoic acid (rs = 0.73, p = 0.003; rs = 0.80, p hydrocarbons; however the substantial partitioning toward the gas phase (Fp ≤ 0.16) and their water sensitivity limit their application as tracers. The outcome of this study is the demonstration that 2,3-dihydroxy-4-oxopentanoic acid, phthalic acid, 4-methylphthalic acid, and 4-hydroxy-3-nitrobenzyl alcohol are good candidates for tracing SOA from aromatic VOCs.

  20. Application of neutron activation tracer sediment technique on environmental science

    Institute of Scientific and Technical Information of China (English)

    YinYi; ZhongWei-Ni; 等

    1997-01-01

    Field and laboratory inverstigations were carried out to study the transport and dispersion law of polluted sediments near wastewater outlet using neutron activation tracer technique.The direction of transport and dispersion of polluted sediments,dispersion amount in different directions,sedimentary region of polluted sediment and evaluation of polluted risk are given.This provided a new test method for the study of environmental science and added a new forecasted content for the evaluation of environmental influence.

  1. nTRACER/COBRA-TF Coupling and Initial Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaejin; Joo, Han Gyu [Seoul National University, Seoul (Korea, Republic of); Perin, Yann; Velkov, Kiril [GRS, Garching (Germany)

    2015-05-15

    The nTRACER direct whole core calculation code being developed at Seoul National University (SNU) has an internal T/H module to determine the temperature and density fields in the reactor. However, this module is based on a quite simplified model and considers only axial flow. The weakness of not-considering radial flow was overcome by coupling the MATRA (Multichannel Analysis for steady-state and Transient in Rod Array) code with nTRACER. MATRA can generate more realistic and detailed T/H field information for nTRACER, but it is a legacy code and does not have an efficient parallel computing capability. On the contrary, the COBRA-TF (Coolant-Boiling in Rod Arrays Two Fluids, CTF) subchannel code, which was developed for the T/H analysis of Light Water Reactor (LWR) vessels, has a good parallel computing capability based on the Message Passing Interface (MPI). The initial assessment of the coupled code demonstrates that more realistic coolant temperatures are obtainable by using CTF. The change in pin power distribution is noted with the realistic flow distribution even though the change is insignificant. The calculation utilizing the boron tracking model of CTF is noticeable. It makes possible for nTRACER to handle nonuniform boron distributions which can be encountered during some transients. Since further validation of the coupling is necessary, the coupling capabilities will be extended to transient applications where non-uniform distributions of inlet parameters such as boron concentration but also coolant temperature can occur.

  2. Design and Fabrication of a Prototype Tracer Surveillance Tester

    Science.gov (United States)

    1983-06-01

    problem with reproducibility and reliability at low spin rates. (6) The existing light sensor assembly and optico - electronic conditioning circuitry...is quite useful to redesign the light sensor assembly/ optico -electronic circuitry so as to obtain quantitative information on the actual intensity...pressurization/depressurization characteristics 31 of the combustion chamber 8a Oscilloscope trace of tracer RPM and light sensor output for 32 30,000

  3. A tracer bolus method for investigating glutamine kinetics in humans.

    Directory of Open Access Journals (Sweden)

    Maiko Mori

    Full Text Available Glutamine transport between tissues is important for the outcome of critically ill patients. Investigation of glutamine kinetics is, therefore, necessary to understand glutamine metabolism in these patients in order to improve future intervention studies. Endogenous glutamine production can be measured by continuous infusion of a glutamine tracer, which necessitates a minimum measurement time period. In order to reduce this problem, we used and validated a tracer bolus injection method. Furthermore, this method was used to measure the glutamine production in healthy volunteers in the post-absorptive state, with extra alanine and with glutamine supplementation and parenteral nutrition. Healthy volunteers received a bolus injection of [1-13C] glutamine, and blood was collected from the radial artery to measure tracer enrichment over 90 minutes. Endogenous rate of appearance (endoRa of glutamine was calculated from the enrichment decay curve and corrected for the extra glutamine supplementation. The glutamine endoRa of healthy volunteers was 6.1±0.9 µmol/kg/min in the post-absorptive state, 6.9±1.0 µmol/kg/min with extra alanyl-glutamine (p = 0.29 versus control, 6.1±0.4 µmol/kg/min with extra alanine only (p = 0.32 versus control, and 7.5±0.9 µmol/kg/min with extra alanyl-glutamine and parenteral nutrition (p = 0.049 versus control. In conclusion, a tracer bolus injection method to measure glutamine endoRa showed good reproducibility and small variation at baseline as well as during parenteral nutrition. Additionally, we showed that parenteral nutrition including alanyl-glutamine increased glutamine endoRa in healthy volunteers, which was not attributable to the alanine part of the dipeptide.

  4. PET and SPET tracers for mapping the cardiac nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Langer, Oliver; Halldin, Christer [Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institute, Karolinska Hospital, 17176 Stockholm (Sweden)

    2002-03-01

    The human cardiac nervous system consists of a sympathetic and a parasympathetic branch with (-)-norepinephrine and acetylcholine as the respective endogenous neurotransmitters. Dysfunction of the cardiac nervous system is implicated in various types of cardiac disease, such as heart failure, myocardial infarction and diabetic autonomic neuropathy. In vivo assessment of the distribution and function of cardiac sympathetic and parasympathetic neurones with positron emission tomography (PET) and single-photon emission tomography (SPET) can be achieved by means of a number of carbon-11-, fluorine-18-, bromine-76- and iodine-123-labelled tracer molecules. Available tracers for mapping sympathetic neurones can be divided into radiolabelled catecholamines, such as 6-[{sup 18}F]fluorodopamine, (-)-6-[{sup 18}F]fluoronorepinephrine and (-)-[{sup 11}C]epinephrine, and radiolabelled catecholamine analogues, such as [{sup 123}I]meta-iodobenzylguanidine, [{sup 11}C]meta-hydroxyephedrine, [{sup 18}F]fluorometaraminol, [{sup 11}C]phenylephrine and meta-[{sup 76}Br]bromobenzylguanidine. Resistance to metabolism by monoamine oxidase and catechol-O-methyl transferase simplifies the myocardial kinetics of the second group. Both groups of compounds are excellent agents for an overall assessment of sympathetic innervation. Biomathematical modelling of tracer kinetics is complicated by the complexity of the steps governing neuronal uptake, retention and release of these agents as well as by their high neuronal affinity, which leads to partial flow dependence of uptake. Mapping of cardiac parasympathetic neurones is limited by a low density and focal distribution pattern of these neurones in myocardium. Available tracers are derivatives of vesamicol, a molecule that binds to a receptor associated with the vesicular acetylcholine transporter. Compounds like (-)-[{sup 18}F]fluoroethoxybenzovesamicol display a high degree of non-specific binding in myocardium which restricts their utility

  5. Thermal tracer tomography: from numerical simulation to field implementation

    Science.gov (United States)

    Somogyvári, Márk; Brauchler, Ralf; Bayer, Peter

    2016-04-01

    Choosing heat for subsurface investigations is attractive because changes in temperature can be easily measured, and natural variations are typically slower than the timescale of the experiments. The tomographical setup expands the applicability of such tests to reconstruct the spatial distribution of hydraulic aquifer properties. A new inversion methodology is presented for thermal tracer tomography, using tracer travel times to invert the hydraulic conductivity distribution of the aquifer. If we can assume that heat transport is driven by advection, the travel time of the thermal tracer can be related to the hydraulic parameters of the aquifer. With this assumption other thermal effects such as thermal diffusion or density driven flow appear as noise in the results. To reduce these effects the early time diagnostics of the recorded breakthrough curves are used, focusing on the fastest transport routes between the sources and receivers. The inverse problem of the experiment thus can be formulated as a classical travel time problem, and it can be solved using standard eikonal solver algorithms known from seismic or hydraulic tomography. The method is demonstrated with a high resolution 3-D aquifer analog dataset. The generated 3-D reconstruction reveals the potential of the method, especially in finding the preferential flow paths within the aquifer. Aside from this, the developed method is computationally efficient and can provide results in a fragment of the time required for full-physics model calibration. The method is also tested under field conditions. Four heat tracer injections were performed during a three day field campaign at the Widen field site in northeast Switzerland. Pulse signals were used and the temperature evolution was measured downstream using a distributed measurement system. The preliminary results of the tomographic inversion correspond well with the findings of earlier studies from the field site imaging the same geological features as

  6. Bromide as a tracer for studying water movement and nitrate displacement in soils: comparison with stable isotope tracers; Bromid als Tracer zur Untersuchung der Wasserbewegung und der Nitratverlagerung in Boeden: Vergleich mit stabilisotopen Tracern

    Energy Technology Data Exchange (ETDEWEB)

    Russow, R.; Knappe, S. [UFZ - Umweltforschungszentrum Leipzig-Halle GmbH, Bad Lauchstaedt (Germany). Sektion Bodenforschung

    1999-02-01

    Tracers are an ideal means of studying water movement and associated nitrate displacement. Often bromide is preferred as a tracer because it is considered a representative tracer for water and because, being a conservative tracer (i.e. not involved in chemical and biological soil processes), it can be used for studying anion transport in soils. Moreover, it is less expensive and easier to measure than the stable isotopes deuterium and {sup 15}N. Its great advantage over radioactive tracers (e.g. tritium), which outweighs their extreme sensitivity and ease of measurement and which it has in common with stable isotopes, is that it does not require radiation protection measures. However, there are also constraints on the use of bromide as a tracer in soil/water/plant systems. Our own studies on different soils using D{sub 2}O, bromide and [{sup 15}N]-nitrate in lysimeters suggest that the above assumptions on bromide tracers need not always be valid under conditions as they prevail in biologically active soils. As the present paper shows, these studies permit a good assessment of the possibilities and limits to these tracers. [Deutsch] Fuer die Untersuchung der Wasserbewegung sowie der daran gekoppelten Nitrat-Verlagerung ist der Einsatz von Tracern das Mittel der Wahl. Dabei wird Bromid als Tracer haeufig bevorzugt, da es allgemein als ein repraesentativer Tracer fuer Wasser und als konservativer Tracer (nicht involviert in chemische und biologische Bodenprozesse) zur Untersuchung des Anionentransportes in Boeden angesehen wird und es gegenueber den stabilen Isotopen Deuterium und {sup 15}N billiger und einfacher zu bestimmen ist. Gegenueber den radioaktiven Tracern (z.B. Tritium), die zwar sehr empfindlich und einfach messbar sind, besteht der grosse Vorteil, dass, wie bei den stabilen Isotopen, keine Strahlenschutzmassnahmen ergriffen werden muessen. Es gibt jedoch auch einschraenkende Hinweise fuer die Verwendung von Bromid als Tracer im System Boden

  7. Application of separable parameter space techniques to multi-tracer PET compartment modeling

    Science.gov (United States)

    Zhang, Jeff L.; Morey, A. Michael; Kadrmas, Dan J.

    2016-02-01

    Multi-tracer positron emission tomography (PET) can image two or more tracers in a single scan, characterizing multiple aspects of biological functions to provide new insights into many diseases. The technique uses dynamic imaging, resulting in time-activity curves that contain contributions from each tracer present. The process of separating and recovering separate images and/or imaging measures for each tracer requires the application of kinetic constraints, which are most commonly applied by fitting parallel compartment models for all tracers. Such multi-tracer compartment modeling presents challenging nonlinear fits in multiple dimensions. This work extends separable parameter space kinetic modeling techniques, previously developed for fitting single-tracer compartment models, to fitting multi-tracer compartment models. The multi-tracer compartment model solution equations were reformulated to maximally separate the linear and nonlinear aspects of the fitting problem, and separable least-squares techniques were applied to effectively reduce the dimensionality of the nonlinear fit. The benefits of the approach are then explored through a number of illustrative examples, including characterization of separable parameter space multi-tracer objective functions and demonstration of exhaustive search fits which guarantee the true global minimum to within arbitrary search precision. Iterative gradient-descent algorithms using Levenberg-Marquardt were also tested, demonstrating improved fitting speed and robustness as compared to corresponding fits using conventional model formulations. The proposed technique overcomes many of the challenges in fitting simultaneous multi-tracer PET compartment models.

  8. Water vapor analysis with use of sunphotometry and radiosoundings

    Science.gov (United States)

    Pakszys, Paulina; Zielinski, Tymon; Petelski, Tomek; Makuch, Przemyslaw; Strzalkowska, Agata; Markuszewski, Piotr; Kowalczyk, Jakub

    2014-05-01

    Information about vertically integrated content of water vapor in the atmosphere and type, composition and concentration of aerosols is relevant in many types of atmospheric studies. Such information is required to understand mechanisms of global climate and its further modeling (Smirnov et al., 2000). This work is devoted to the description of a basic technique of analysis and comparing the derivation of Columnar Water Vapor (CWV) from different instruments, such as a radiosonde and a sunphotometer. The measurements were carried out using Microtops II Ozone Monitor & Sunphotometer during the cruises onboard the R/V Oceania (13 cruises) and from one cruise onboard of the SY TASK in the southern Baltic Sea. Measurements were collected for the NASA program Maritime Aerosol Network. Data collected with the DiGICORA III Radiosonde (RS92) come from the webpage of the University of Wyoming, Department of Atmospheric Science. The first instrument, sunphotometer, allows us to collect data on days that are cloud-free. The Microtops II is capable of measuring the total ozone column, total precipitable water vapor and aerosol optical depth at 1020 nm (Morys et al. 2001; Ichoku et al., 2002). Each of these parameters is automatically derived. Data collected by Microtops have been processed with the pre- and post-field calibration and automatic cloud clearing. Precipitable water vapor in the column was derived from the 936nm channel. Detailed data description is available on the AERONET webpage. In radiousoundings the total precipitable water is the water that occurs in a vertical column of a unit cross-sectional area between any two specified levels, commonly expressed as from the earth's surface to the 'top' of the atmosphere. The Integrated Precipitable Water Vapor (IPWV) is the height of liquid water that would result from the condensation of all water vapor in a column. The study of one cruise (29 March - 20 April) shows that 241 Microtops measurements were made, each of

  9. Radioisotope tracer study in a sludge hygienization research irradiator (SHRI).

    Science.gov (United States)

    Pant, H J; Thýn, J; Zitný, R; Bhatt, B C

    2001-01-01

    A radioisotope tracer study has been carried out in a batch type sludge hygienization research irradiator with flow from top to bottom, the objective being to measure flow rate, circulation and mixing times and to investigate the hydrodynamic behaviour of the irradiator for identifying the cause(s) of malfunction. A stimulus-response technique with NH4(82)Br as a tracer was used to measure the above parameters. Experiments were carried out at three different flow rates, i.e 1.0, 0.64 and 0.33 m3/min. Three combined models based on a set of differential equations are proposed and used to simulate the measured tracer concentration curves. The obtained parameters were used to estimate dead volume and analyse hydrodynamic behaviour of the irradiator. The nonlinear regression problem of model parameter estimation was solved using the Marquardt-Levenberg method. The measured flow rate was found to be in good agreement with the values shown by the flow meter. The circulation times were found to be half of the mixing times. A simple approach for estimation of dose based on a known vertical dose-rate profile inside the irradiator is presented. About one-fourth of the volume of the irradiator was found to be dead at lower flow rates and this decreased with increase in flow rate. At higher flow rates, a semi stagnant volume was found with slow exchange of flow between the active and dead volumes.

  10. Radioisotope tracer study in a sludge hygienization research irradiator (SHRI)

    Energy Technology Data Exchange (ETDEWEB)

    Pant, H.J. E-mail: hjpant@aspsara.barc.ernet.in; Thyn, J.; Zitny, R.; Bhatt, B.C

    2001-01-15

    A radioisotope tracer study has been carried out in a batch type sludge hygienization research irradiator with flow from top to bottom, the objective being to measure flow rate, circulation and mixing times and to investigate the hydrodynamic behaviour of the irradiator for identifying the cause(s) of malfunction. A stimulus-response technique with NH{sup 82}{sub 4}Br as a tracer was used to measure the above parameters. Experiments were carried out at three different flow rates, i.e 1.0, 0.64 and 0.33 m{sup 3}/min. Three combined models based on a set of differential equations are proposed and used to simulate the measured tracer concentration curves. The obtained parameters were used to estimate dead volume and analyse hydrodynamic behaviour of the irradiator. The nonlinear regression problem of model parameter estimation was solved using the Marquardt-Levenberg method. The measured flow rate was found to be in good agreement with the values shown by the flow meter. The circulation times were found to be half of the mixing times. A simple approach for estimation of dose based on a known vertical dose-rate profile inside the irradiator is presented. About one-fourth of the volume of the irradiator was found to be dead at lower flow rates and this decreased with increase in flow rate. At higher flow rates, a semi stagnant volume was found with slow exchange of flow between the active and dead volumes.

  11. Using atmospheric tracers to reduce uncertainty in groundwater recharge areas.

    Science.gov (United States)

    Starn, J Jeffrey; Bagtzoglou, Amvrossios C; Robbins, Gary A

    2010-01-01

    A Monte Carlo-based approach to assess uncertainty in recharge areas shows that incorporation of atmospheric tracer observations (in this case, tritium concentration) and prior information on model parameters leads to more precise predictions of recharge areas. Variance-covariance matrices, from model calibration and calculation of sensitivities, were used to generate parameter sets that account for parameter correlation and uncertainty. Constraining parameter sets to those that met acceptance criteria, which included a standard error criterion, did not appear to bias model results. Although the addition of atmospheric tracer observations and prior information produced similar changes in the extent of predicted recharge areas, prior information had the effect of increasing probabilities within the recharge area to a greater extent than atmospheric tracer observations. Uncertainty in the recharge area propagates into predictions that directly affect water quality, such as land cover in the recharge area associated with a well and the residence time associated with the well. Assessments of well vulnerability that depend on these factors should include an assessment of model parameter uncertainty. A formal simulation of parameter uncertainty can be used to delineate probabilistic recharge areas, and the results can be expressed in ways that can be useful to water-resource managers. Although no one model is the correct model, the results of multiple models can be evaluated in terms of the decision being made and the probability of a given outcome from each model.

  12. Radon as tracer to identify discharge sections at Juatuba basin

    Energy Technology Data Exchange (ETDEWEB)

    Chagas, Claudio Jose; Ferreira, Vinicius Verna Magalhaes; Fonseca, Raquel Luisa Mageste; Rocha, Zildete; Moreira, Rubens Martins; Lemos, Nayron Cosme; Menezes, Angela de Barros Correia, E-mail: vvmf@cdtn.br, E-mail: rlmf@cdtn.br, E-mail: cjc@cdtn.br, E-mail: rochaz@cdtn.br, E-mail: rubens@cdtn.br, E-mail: menezes@cdtn.br, E-mail: lemosnc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Santos, Talita Oliveira, E-mail: talitaolsantos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Departamento de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2015-07-01

    The use of natural tracers in hydrological studies is a very useful tool, being applied in several studies. One of these tracers is the radon, {sup 222}Rn, noble gas derived from natural sources, been found in all underground waters, as a product of radioactive decay of the {sup 226}Ra. This gas can be found in the air, water, rocks or soil. In this paper, the {sup 222}Rn detection in surface water was used as tracer in order to identify aquifer discharge sections in surface water at the Fundao stream, which belongs to the Juatuba river basin, through the second semester of 2014 and the first semester of 2015, in three sampling campaigns. The {sup 222}Rn measurements at Fundao stream were carried out using the equipment RAD 7. The results showed that {sup 222}Rn is present in some sections of the water course suggesting that there is a connection between groundwater and surface water. It also justifies the variation in the water level in the stream, recorded by a fluviometric station. (author)

  13. A galaxy-halo model for multiple cosmological tracers

    Science.gov (United States)

    Bull, Philip

    2017-10-01

    The information extracted from large galaxy surveys with the likes of DES, DESI, Euclid, LSST, SKA, and WFIRST will be greatly enhanced if the resultant galaxy catalogues can be cross-correlated with one another. Predicting the nature of the information gain, and developing the tools to realize it, depends on establishing a consistent model of how the galaxies detected by each survey trace the same underlying matter distribution. Existing analytic methods, such as halo occupation distribution modelling, are not well suited for this task, and can suffer from ambiguities and tuning issues when applied to multiple tracers. In this paper, we take the first step towards constructing an alternative that provides a common model for the connection between galaxies and dark matter haloes across a wide range of wavelengths (and thus tracer populations). This is based on a chain of parametrized statistical distributions that model the connection between (i) halo mass and bulk physical properties of galaxies, such as star formation rate; and (ii) those same physical properties and a variety of emission processes. The result is a flexible parametric model that allows analytic halo model calculations of one-point functions to be carried out for multiple tracers, as well as providing semi realistic galaxy properties for fast mock catalogue generation.

  14. Consistency Problem with Tracer Advection in the Atmospheric Model GAMIL

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kai; WAN Hui; WANG Bin; ZHANG Meigen

    2008-01-01

    The radon transport test,which is a widely used test case for atmospheric transport models,is carried out to evaluate the tracer advection schemes in the Grid-Point Atmospheric Model of IAP-LASG (GAMIL).TWO of the three available schemes in the model are found to be associated with significant biases in the polar regions and in the upper part of the atmosphere,which implies potentially large errors in the simulation of ozone-like tracers.Theoretical analyses show that inconsistency exists between the advection schemes and the discrete continuity equation in the dynamical core of GAMIL and consequently leads to spurious sources and sinks in the tracer transport equation.The impact of this type of inconsistency is demonstrated by idealized tests and identified as the cause of the aforementioned biases.Other potential effects of this inconsistency are also discussed.Results of this study provide some hints for choosing suitable advection schemes in the GAMIL model.At least for the polar-region-concentrated atmospheric components and the closely correlated chemical species,the Flux-Form Semi-Lagrangian advection scheme produces more reasonable simulations of the large-scale transport processes without significantly increasing the computational expense.

  15. Metal stable isotope signatures as tracers in environmental geochemistry.

    Science.gov (United States)

    Wiederhold, Jan G

    2015-03-03

    The biogeochemical cycling of metals in natural systems is often accompanied by stable isotope fractionation which can now be measured due to recent analytical advances. In consequence, a new research field has emerged over the last two decades, complementing the traditional stable isotope systems (H, C, O, N, S) with many more elements across the periodic table (Li, B, Mg, Si, Cl, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Ge, Se, Br, Sr, Mo, Ag, Cd, Sn, Sb, Te, Ba, W, Pt, Hg, Tl, U) which are being explored and potentially applicable as novel geochemical tracers. This review presents the application of metal stable isotopes as source and process tracers in environmental studies, in particular by using mixing and Rayleigh model approaches. The most important concepts of mass-dependent and mass-independent metal stable isotope fractionation are introduced, and the extent of natural isotopic variations for different elements is compared. A particular focus lies on a discussion of processes (redox transformations, complexation, sorption, precipitation, dissolution, evaporation, diffusion, biological cycling) which are able to induce metal stable isotope fractionation in environmental systems. Additionally, the usefulness and limitations of metal stable isotope signatures as tracers in environmental geochemistry are discussed and future perspectives presented.

  16. An investigation of radial tracer flow in naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Jetzabeth, Ramirez-Sabag; Fernando, Samaniego V.; Jesus, Rivera R.; Fernando Rodriguez

    1991-01-01

    This study presents a general solution for the radial flow of tracers in naturally fractured reservoirs. Continuous and finite step injection of chemical and radioactive tracers are considered. The reservoir is treated as being composed of two regions: a mobile region where longitudinal dispersion and convection take place and a stagnant region where only diffusion and adsorption are allowed. Radioactive decay is considered in both regions. The model of this study is thoroughly compared to those previously presented in literature by Moench and Ogata, Tang et al., Chen et al., and Hsieh et al. The solution is numerically inverted by means of the Crump algorithm. A detailed validation of the model with respect to solutions previously presented and/or simplified physical conditions solutions (i.e., homogeneous case) or limit solutions (i.e., for short times) was carried out. The influence of various dimensionless parameters that enter into the solution was investigated. A discussion of results obtained through the Crump and Stehfest algorithm is presented, concluding that the Crump method provides more reliable tracer concentrations.

  17. Methane emission quantification from landfills using a double tracer approach

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Samuelsson, J.; Fredenslund, Anders Michael

    2007-01-01

    in the October respectively February measurement. The CH4 emission from the compost area was 0.5 kg CH4 h-1, whereas the carbon dioxide (CO2) flux and nitrous oxide (N2O) was quantified to be in the order of 332 kg CO2 h-1 and 0.06 kg N2O h-1 respectively. The sludge pit located west of the compost material......A tracer method was successfully used for quantification of the whole methane (CH4) emission from Fakse landfill. By using two different tracers the emission from different sections of the landfill could be quantified. Furthermore, is was possible to determine the emissions from local on site...... sources; a composting facility and a sewage sludge storage unit by scaling the tracer method down. Two field campaigns were performed; during October 11-12, 2006 and February 19-20, 2007. At both field campaigns an overall leak search showed that the CH4 emission from the old landfill section...

  18. Lattice-Boltzmann Simulations of Microswimmer-Tracer Interactions

    CERN Document Server

    de Graaf, Joost

    2016-01-01

    Hydrodynamic interactions in systems comprised of self-propelled particles, such as swimming microorganisms, and passive tracers have a significant impact on the tracer dynamics compared to the equivalent "dry" sample. However, such interactions are often difficult to take into account in simulations due to their computational cost. Here, we perform a systematic investigation of swimmer-tracer interaction using an efficient force/counter-force based lattice-Boltzmann (LB) algorithm [J. de Graaf~\\textit{et al.}, J. Chem. Phys.~\\textbf{144}, 134106 (2016)], in order to validate its applicability to study large-scale microswimmer suspensions. We show that the LB algorithm reproduces far-field theoretical results well, both in a system with periodic boundary conditions and in a spherical cavity with no-slip walls, for which we derive expressions here. The LB algorithm has an inherent near-field renormalization of the flow field, due to the force interpolation between the swimmers and the lattice. This strongly pe...

  19. Studies of Tracer Dispersion and Fluid Flow in Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Rage, T.

    1996-12-31

    This doctoral thesis explores the connection between the topology of a porous medium and its macroscopic transport properties and is based on computerized simulation. In porous media, both diffusion and convection contribute to the dispersion of a tracer and their combined effect is emphasized. The governing equations are solved numerically, using finite differences and Monte Carlo technique. The influence of finite Reynolds number on the outcome of echo-experiments is discussed. Comparing experiments and simulations it is found that nonlinear inertial forces lead to a visible deformation of a returned tracer at surprisingly small Reynolds numbers. In a study of tracer dispersion and fluid flow in periodic arrays of discs it is demonstrated that the mechanisms of mechanical dispersion in periodic media and in natural (non-periodic) porous media are essentially different. Measurements of the percolation probability distribution of a sandstone sample is presented. Local porosity theory predicts that this simple geometric function of a porous medium is of dominant importance for its macroscopic transport properties. It is demonstrated that many aspects of transport through fractures can be studied by using simple but realistic models and readily available computer resources. An example may be the transport of hydrocarbon fluids from the source rock to a reservoir. 165 refs., 44 figs., 1 table

  20. Application of transition metal isotope tracers in global change research

    Institute of Scientific and Technical Information of China (English)

    SONG Jinming; Thomas F. Pedersen

    2005-01-01

    High-precision isotope composition determinations using multicollector, magnetic-sector inductively coupled plasma mass spectrometry (MC-ICPMS) have recently revealed that some transition metal isotopes such as those of Mo, Fe, Cu, Zn etc. can be used as biogeochemical tracers in global change research.The Mo isotope system may be useful in paleoredox investigations indicating that δ 97/95Mo in seawater may co-vary with changes in the relative proportions of anoxic and oxic sedimentation in the ocean, and that this variation may be recorded in δ 97/95Mo of anoxic sediments. The Mo continental flux into the oceans and the global Mo isotope budget can be estimated fromδ 97/95MO values. The Fe isotope composition in seawater is an important issue because Fe plays a controlling role in biological productivity in the oceans and its abundance in seawater may have substantial effect on climate changes. Iron isotope fractionations could result from bio- and abio-processes and have about 0.1% variation (δ 56/54Fe), so Fe isotopes considered alone cannot be used to distinguish the products of abiotic and biotic Fe processing in geological records. Cu and Zn isotopes are also used as biogeochemical tracers, but the researches are relatively less. This review mainly focuses on the methods for preparation, purification and determination of new isotope tracer samples, and on isotope applications in marine environmental changes.

  1. Cosmological constraints from multiple tracers in spectroscopic surveys

    CERN Document Server

    Alarcon, Alex; Gaztañaga, Enrique

    2016-01-01

    We use the Fisher matrix formalism to study the expansion and growth history of the Universe using galaxy clustering with 2D angular cross-correlation tomography in spectroscopic or high resolution photometric redshift surveys. The radial information is contained in the cross correlations between narrow redshift bins. We show how multiple tracers with redshift space distortions cancel sample variance and arbitrarily improve the constraints on the dark energy equation of state $\\omega(z)$ and the growth parameter $\\gamma$ in the noiseless limit. The improvement for multiple tracers quickly increases with the bias difference between the tracers, up to a factor $\\sim4$ in $\\text{FoM}_{\\gamma\\omega}$. We model a magnitude limited survey with realistic density and bias using a conditional luminosity function, finding a factor 1.3-9.0 improvement in $\\text{FoM}_{\\gamma\\omega}$ -- depending on global density -- with a split in a halo mass proxy. Partly overlapping redshift bins improve the constraints in multiple tr...

  2. Assessment and control of chemical risk from organic vapors for attendants in a gas station

    Directory of Open Access Journals (Sweden)

    Stephanie Ehmig Santillán

    2015-12-01

    Full Text Available This research comprises monitoring, assessment and recommendations for chemical risk originating from organic vapors (benzene, toluene and xylene of fuel (super and extra gasoline to which attendants at a gas station are exposed. Given the concentration measured of organic vapors (benzene, toluene and xylene the chemical risk to which attendants are exposed in the supply area is acceptable. Control measures are recommended to ensure healthy working conditions for gas station attendants and also to avoid occurrence of occupational diseases in the medium or long term

  3. Entropically induced asymmetric passage times of charged tracers across corrugated channels

    Energy Technology Data Exchange (ETDEWEB)

    Malgaretti, Paolo, E-mail: malgaretti@is.mpg.de [Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, D-70569 Stuttgart (Germany); IV Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart (Germany); Department de Fisica Fonamental, Universitat de Barcelona, Barcelona (Spain); Pagonabarraga, Ignacio; Miguel Rubi, J. [Department de Fisica Fonamental, Universitat de Barcelona, Barcelona (Spain)

    2016-01-21

    We analyze the diffusion of charged and neutral tracers suspended in an electrolyte embedded in a channel of varying cross section. Making use of systematic approximations, the diffusion equation governing the motion of tracers is mapped into an effective 1D equation describing the dynamics along the longitudinal axis of the channel where its varying-section is encoded as an effective entropic potential. This simplified approach allows us to characterize tracer diffusion under generic confinement by measuring their mean first passage time (MFPT). In particular, we show that the interplay between geometrical confinement and electrostatic interactions strongly affect the MFTP of tracers across corrugated channels hence leading to alternative means to control tracers translocation across charged pores. Finally, our results show that the MFPTs of a charged tracer in opposite directions along an asymmetric channel may differ We expect our results to be relevant for biological as well synthetic devices whose dynamics is controlled by the detection of diluted tracers.

  4. Entropically induced asymmetric passage times of charged tracers across corrugated channels.

    Science.gov (United States)

    Malgaretti, Paolo; Pagonabarraga, Ignacio; Rubi, J Miguel

    2016-01-21

    We analyze the diffusion of charged and neutral tracers suspended in an electrolyte embedded in a channel of varying cross section. Making use of systematic approximations, the diffusion equation governing the motion of tracers is mapped into an effective 1D equation describing the dynamics along the longitudinal axis of the channel where its varying-section is encoded as an effective entropic potential. This simplified approach allows us to characterize tracer diffusion under generic confinement by measuring their mean first passage time (MFPT). In particular, we show that the interplay between geometrical confinement and electrostatic interactions strongly affect the MFTP of tracers across corrugated channels hence leading to alternative means to control tracers translocation across charged pores. Finally, our results show that the MFPTs of a charged tracer in opposite directions along an asymmetric channel may differ We expect our results to be relevant for biological as well synthetic devices whose dynamics is controlled by the detection of diluted tracers.

  5. In-Situ Characterization of Dense Non-Aqueous Phase Liquids Using Partitioning Tracers

    Energy Technology Data Exchange (ETDEWEB)

    Gary A. Pope; Daene C. McKinney; Akhil Datta Gupta; Richard E. Jackson; Minquan Jin

    2000-03-20

    Majors advances have been made during the past three years in our research on interwell partitioning tracers tests (PITTs). These advances include (1) progress on the inverse problem of how to estimate the three-dimensional distribution of NAPL in aquifers from the tracer data, (2) the first ever partitioning tracer experiments in dual porosity media, (3) the first modeling of partitioning tracers in dual porosity media (4) experiments with complex NAPLs such as coal tar, (5) the development of an accurate and simple method to predict partition coefficients using the equivalent alkane carbon number approach, (6) partitioning tracer experiments in large model aquifers with permeability layers, (7) the first ever analysis of partitioning tracer data to estimate the change in composition of a NAPL before and after remediation (8) the first ever analysis of partitioning tracer data after a field demonstration of surfactant foam to remediate NAPL and (9) experiments at elevated temperatures .

  6. Estimation of Fluorescent Dye Amount in Tracer Dye Test

    Science.gov (United States)

    Pekkan, Emrah; Balkan, Erman; Balkan, Emir

    2015-04-01

    Karstic groundwater is more influenced by human than the groundwater that disperse in pores. On the other hand karstic groundwater resources, in addition to providing agricultural needs, livestock breeding, drinking and domestic water in most of the months of the year, they also supply drinking water to the wild life at high altitudes. Therefore sustainability and hydrogeological investigation of karstic resources is critical. Tracing techniques are widely used in hydrologic and hydrogeologic studies to determine water storage, flow rate, direction and protection area of groundwater resources. Karanfil Mountain (2800 m), located in Adana, Turkey, is one of the karstic recharge areas of the natural springs spread around its periphery. During explorations of the caves of Karanfil mountain, a 600 m deep cave was found by the Turkish and Polish cavers. At the bottom of the cave there is an underground river with a flow rate of approximately 0.5 m3/s during August 2014. The main spring is located 8 km far from the cave's entrance and its mean flow rate changes between 3.4 m3/s and 0.21 m3/s in March and September respectively according to a flowrate observation station of Directorate of Water Works of Turkey. As such frequent storms, snowmelt and normal seasonal variations in rainfall have a significant and rapid effect on the volume of this main spring resource. The objective of our research is to determine and estimate dye amount before its application on the field inspired from the previously literature on the subject. This estimation is intended to provide a preliminary application of a tracer test of a karstic system. In this study dye injection, inlet point will be an underground river located inside the cave and the observation station will be the spring that is approximately 8 km far from the cave entrance. On the other hand there is 600 meter elevation difference between cave entrance and outlet spring. In this test Rodamin-WT will be used as tracer and the

  7. A comparison of resting images from two myocardial perfusion tracers

    Energy Technology Data Exchange (ETDEWEB)

    Anagnostopoulos, C. [Royal Brompton Hospital, London (United Kingdom); Laney, R. [Royal Brompton Hospital, London (United Kingdom); Pennell, D. [National Heart and Lung Inst., London (United Kingdom); Proukakis, H. [University of Athens Medical School (Greece); Underwood, R. [National Heart and Lung Inst., London (United Kingdom)

    1995-09-01

    We have compared stress-redistribution and delayed rest thallium-201 with rest technetium-99m methoxyisobutylisonitrile (MIBI) tomograms in order to compare the tracers for the assessment of myocardial viability and to validate a rapid protocol combining the two tracers. We studied 30 consecutive patients with known or suspected coronary artery disease [group 1: 16 with normal left ventricular function, mean left ventricular ejection fraction (LVEF) 55%, SD 6%; group 2: 14 with abnormal function, mean LVEF 28%, SD 8%]. {sup 201}Tl was injected during infusion of adenosine followed by acquisition of conventional stress and redistribution tomograms. On a separate day, {sup 201}Tl was injected at rest with imaging 4 h later. {sup 99m}Tc-MIBI was then given at rest and imaging was performed. Three images were compared: redistribution {sup 201}Tl, rest {sup 201}Tl, and rest {sup 99m}Tc-MIBI. Tracer activity was classified visually and quantitatively in nine segments and segments with>50% activity were defined as containing clinically significant viable myocardium. Mean global tracer uptake as a percentage of maximum was similar in group 1 (rest {sup 201}Tl 69%{+-}12%, redistribution {sup 201}Tl 69%{+-}15%, rest {sup 99m}Tc-MIBI 70%{+-}13%), but in group 2 mean tracer uptake was significantly greater in the rest {sup 201}Tl images (59%{+-}16%) than in redistribution {sup 201}Tl images (53%{+-}17%) or rest {sup 99m}Tc-MIBI images (53%{+-}19%). Overall agreement for regional uptake score was excellent ({kappa} from 0.79 to 0.84), although there were a significant number of segments with less uptake shown by redistribution {sup 201}Tl and by rest {sup 99m}Tc-MIBI than by rest {sup 201}Tl in group 2. The number of segments with significant viable myocardium in group 1 was very similar between the three images but in group 2 rest {sup 201}Tl identified significantly more segments as viable than the other images. (orig./MG) (orig.). With 1 fig., 7 tabs.

  8. Determination of Transport Parameters in Unsaturated Zone by Tracer Experiment in the Porous Aquifer located at Ljubljana, Slovenia

    Science.gov (United States)

    Vidmar, S.; Cencur Curk, B.

    2009-04-01

    tracer experiment was performed. Uranine was used as a tracer with a single time injection (1 kg) directly into the unsaturated zone. To achieve no sorption on organic particles the top layer of the ground (approx. 1m) was removed. The concentrations of the tracer spreading were observed in the well which is down gradient (approx. 22m) from the injection point. The tracer experiment was monitored for 305 days with records recorded every 4 minutes. All major events observed from the breakthrough curve, corresponded to rain events with a different delay depending on the water content in the unsaturated zone. When the unsaturated zone contains water the response in the observation well was faster than when the unsaturated zone was dry. The obtained data have been used in an analytical method (Multi-Dispersion-Model (MDM)). This solution provided the following transport parameters: mean transit time, mean velocity, longitudinal dispersion and dispersivity. The obtained parameters from the analytical solution will also be verified in the numerical model. The final results should enable better knowledge of the solute transport parameters and thus a better understanding of pollution dispersion as a help for water supply management system including measures for pollution prevention and as an actions/measure scenario in case of pollution.

  9. El vapor de ruedas "Cid": de pionero de la navegación comercial a vapor a primer vapor hospital

    Directory of Open Access Journals (Sweden)

    O. González García

    Full Text Available La aparición de la máquina de vapor había hecho realidad el sueño de navegar sin depender de las fuerzas de la naturaleza. La carrera por lograr un vapor comercial eficiente había comenzado. Con retraso por la Guerra de la Independencia, España se incorporó a la carrera. Entre los primeros vapores comerciales estaba el vapor "Cid". En 1859, en la Guerra de África, ante la necesidad de una evacuación regular de bajas se designa al "Cid" como buque hospital, fue la primera vez en el mundo que se usó un vapor hospital. El Dr. Nicasio Landa fue el responsable de realizar la misión con una organización moderna, eficaz y ejemplar. Pronto los vapores de ruedas perdieron su batalla con los de hélice y el "Cid" quedó obsoleto. Sin embargo, a pesar de su corta vida operativa, poco más de quince años, escribió una importante página en la historia de la navegación en España.

  10. Characterization of tau positron emission tomography tracer [(18)F]AV-1451 binding to postmortem tissue in Alzheimer's disease, primary tauopathies, and other dementias.

    Science.gov (United States)

    Sander, Kerstin; Lashley, Tammaryn; Gami, Priya; Gendron, Thibault; Lythgoe, Mark F; Rohrer, Jonathan D; Schott, Jonathan M; Revesz, Tamas; Fox, Nick C; Årstad, Erik

    2016-11-01

    Aggregation of tau is a hallmark of many neurodegenerative diseases, and tau imaging with positron emission tomography (PET) may allow early diagnosis and treatment monitoring. We assessed binding of the PET tracer [(18)F]AV-1451 in a range of dementias. Phosphorimaging was used to quantify binding to postmortem brain tissue from 33 patients with different, histopathologically characterized, neurodegenerative dementias. [(18)F]AV-1451 showed high specific binding in cases with Alzheimer's disease (AD), moderate binding in Pick's disease and frontotemporal dementia with parkinsonism-17, and low but displaceable binding in corticobasal degeneration, progressive supranuclear palsy, non-tau proteinopathies, and in controls without pathology. Tracer binding did not correlate with tau load within disease groups. [(18)F]AV-1451 binds to tau in AD, and some other tauopathies. However, evidence for a non-tau binding site and lack of correlation between tracer binding and antibody staining suggest that reliable quantification of tau load with this tracer is problematic. Copyright © 2016 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

  11. Analytical modeling of the subsurface volatile organic vapor concentration in vapor intrusion.

    Science.gov (United States)

    Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2014-01-01

    The inhalation of volatile and semi-volatile organic compounds that intrude from a subsurface contaminant source into indoor air has become the subject of health and safety concerns over the last twenty years. Building subslab and soil gas contaminant vapor concentration sampling have become integral parts of vapor intrusion field investigations. While numerical models can be of use in analyzing field data and in helping understand the subslab and soil gas vapor concentrations, they are not widely used due to the perceived effort in setting them up. In this manuscript, we present a new closed-form analytical expression describing subsurface contaminant vapor concentrations, including subslab vapor concentrations. The expression was derived using Schwarz-Christoffel mapping. Results from this analytical model match well the numerical modeling results. This manuscript also explores the relationship between subslab and exterior soil gas vapor concentrations, and offers insights on what parameters need to receive greater focus in field studies.

  12. MULTISPECIES REACTIVE TRACER TEST IN A SAND AND GRAVEL AQUIFER, CAPE COD, MASSACHUSETTS: PART 2: TRANSPORT OF CHROMIUM (VI) AND LEAD-, COPPER-, AND ZINC-EDTA TRACERS

    Science.gov (United States)

    This report discusses the transport of a group of reactive tracers over the course of a large-scale, natural gradient tracer test conducted at the USGS Cape Cod Toxic Substances Hydrology Research site, near Falmouth, Massachusetts. The overall objectives of the experiment were ...

  13. Water Vapor Corrosion in EBC Constituent Materials

    Science.gov (United States)

    Kowalski, Benjamin; Fox, Dennis; Jacobson, Nathan S.

    2017-01-01

    Environmental Barrier Coating (EBC) materials are sought after to protect ceramic matrix composites (CMC) in high temperature turbine engines. CMCs are particularly susceptible to degradation from oxidation, Ca-Al-Mg-Silicate (CMAS), and water vapor during high temperature operation which necessitates the use of EBCs. However, the work presented here focuses on water vapor induced recession in EBC constituent materials. For example, in the presence of water vapor, silica will react to form Si(OH)4 (g) which will eventually corrode the material away. To investigate the recession rate in EBC constituent materials under high temperature water vapor conditions, thermal gravimetric analysis (TGA) is employed. The degradation process can then be modeled through a simple boundary layer expression. Ultimately, comparisons are made between various single- and poly-crystalline materials (e.g. TiO2, SiO2) against those found in literature.

  14. Static Water Vapor Feed Electrolyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a static vapor feed electrolyzer utilizing an advanced bipolar plate that produces sub-saturated H2 and O2 is proposed. This novel bipolar design can...

  15. Leidenfrost Vapor Layer Stabilization on Superhydrophobic Surfaces

    Science.gov (United States)

    Vakarelski, Ivan; Patankar, Neelesh; Marston, Jeremy; Chan, Derek; Thoroddsen, Sigurdur

    2012-11-01

    We have performed experiments to investigate the influence of the wettability of a superheated metallic sphere on the stability of a thin vapor layer during the cooling of a sphere immersed in water. For high enough sphere temperatures, a continuous vapor layer (Leidenfrost regime) is observed on the surface of non-superhydrophobic spheres, but below a critical sphere temperature the layer becomes unstable and explosively switches to nuclear boiling regime. In contrast, when the sphere surface is textured and superhydrophobic, the vapor layer is stable and gradually relaxes to the sphere surface until the complete cooling of the sphere, thus avoiding the nuclear boiling transition altogether. This finding could help in the development of heat exchange devices and of vapor layer based drag reducing technologies.

  16. Colorometric detection of ethylene glycol vapor

    Science.gov (United States)

    Helm, C.; Mosier, B.; Verostko, C. E.

    1970-01-01

    Very low concentrations of ethylene glycol in air or other gases are detected by passing a sample through a glass tube with three partitioned compartments containing reagents which successively convert the ethylene glycol vapor into a colored compound.

  17. DMSP SSMT/2 - Atmospheric Water Vapor Profiler

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line and...

  18. Static Water Vapor Feed Electrolyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a static vapor feed electrolyzer utilizing an advanced bipolar plate that produces sub-saturated H2 and O2 is proposed. This novel bipolar design can...

  19. Analytical modeling of the subsurface volatile organic vapor concentration in vapor intrusion

    OpenAIRE

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    The inhalation of volatile and semi-volatile organic compounds that intrude from a subsurface contaminant source into indoor air has become the subject of health and safety concerns over the last twenty years. Building subslab and soil gas contaminant vapor concentration sampling have become integral parts of vapor intrusion field investigations. While numerical models can be of use in analyzing field data and in helping understand the subslab and soil gas vapor concentrations, they are not w...

  20. Deposition of heavy water vapor from air to plant and soil

    Energy Technology Data Exchange (ETDEWEB)

    Andoh, Mariko; Amano, Hikaru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ichimasa, Michiko; Ichimasa, Yusuke

    1999-03-01

    When tritium is released into the atmosphere, plants play an important role in processes of tritium transfer in the environment. However, available data is limited because the uptake of tritium into a plant is affected by many factors such as plant growth, humidity, solar radiation, stomatal condition - all of which vary in daily and seasonal cycles. Deuterium, a stable isotope of tritium, was released as a tracer of tritium in the form of D{sub 2}O vapor in a greenhouse to study the transfer of tritium from air to plants and soils. The deposition rate of D{sub 2}O from the air to plant leaves was measured in a daytime and in a nighttime, and the results were compared. After D{sub 2}O release stopped, decline of D{sub 2}O concentrations in plant free water was measured. (author)

  1. Influence of sea ice on ocean water vapor isotopes and Greenland ice core records

    Science.gov (United States)

    Klein, Eric S.; Welker, Jeffrey M.

    2016-12-01

    A warming climate results in sea ice loss and impacts to the Arctic water cycle. The water isotope parameter deuterium excess, a moisture source proxy, can serve as a tracer to help understand hydrological changes due to sea ice loss. However, unlocking the sea ice change signal of isotopes from ice cores requires understanding how sea ice changes impact deuterium excess, which is unknown. Here we present the first isotope data linking a gradient of sea ice extents to oceanic water vapor deuterium excess values. Initial loss of sea ice extent leads to lower deuterium excess moisture sources, and then values progressively increase with further ice loss. Our new process-based interpretation suggests that past rapid (1-3 years) Greenland ice core changes in deuterium excess during warming might not be the result of abrupt atmospheric circulation shifts, but rather gradual loss of sea ice extent at northern latitude moisture sources.

  2. Tracing freshwater nitrate sources in pre-alpine groundwater catchments using environmental tracers

    Science.gov (United States)

    Stoewer, M. M.; Knöller, K.; Stumpp, C.

    2015-05-01

    Groundwater is one of the main resources for drinking water. Its quality is still threatened by the widespread contaminant nitrate (NO3-). In order to manage groundwater resources in a sustainable manner, we need to find options of lowering nitrate input. Particularly, a comprehensive knowledge of nitrate sources is required in areas which are important current and future drinking water reservoirs such as pre-alpine aquifers covered with permanent grassland. The objective of the present study was to identify major sources of nitrate in groundwater with low mean nitrate concentrations (8 ± 2 mg/L). To achieve the objective, we used environmental tracer approaches in four pre-alpine groundwater catchments. The stable isotope composition and tritium content of water were used to study the hydrogeology and transit times. Furthermore, nitrate stable isotope methods were applied to trace nitrogen from its sources to groundwater. The results of the nitrate isotope analysis showed that groundwater nitrate was derived from nitrification of a variety of ammonium sources such as atmospheric deposition, mineral and organic fertilizers and soil organic matter. A direct influence of mineral fertilizer, atmospheric deposition and sewage was excluded. Since temporal variation in stable isotopes of nitrate were detected only in surface water and locally at one groundwater monitoring well, aquifers appeared to be well mixed and influenced by a continuous nitrate input mainly from soil derived nitrogen. Hydrogeological analysis supported that the investigated aquifers were less vulnerable to rapid impacts due to long average transit times, ranging from 5 to 21 years. Our study revealed the importance of combining environmental tracer approaches and a comprehensive sampling campaign (local sources of nitrate, soil water, river water, and groundwater) to identify the nitrate sources in groundwater and its vulnerability. In future, the achieved results will help develop targeted

  3. Determining metal assimilation efficiency in aquatic invertebrates using enriched stable metal isotope tracers

    Science.gov (United States)

    Croteau, M.-N.; Luoma, S.N.; Pellet, B.

    2007-01-01

    We employ a novel approach that combines pulse-chase feeding and multi-labelled stable isotopes to determine gut passage time (GPT), gut retention time (GRT), food ingestion rate (IR) and assimilation efficiency (AE) of three trace elements for a freshwater gastropod. Lettuce isotopically enriched in 53Cr, 65Cu and 106Cd was fed for 2 h to Lymnaea stagnalis. The release of tracers in feces and water was monitored for 48 h, during which unlabelled lettuce was provided ad libidum. The first defecation of 53Cr occurred after 5 h of depuration (GPT), whereas 90% of the ingested 53Cr was recovered in the feces after 22.5 h of depuration (GRT). 53Chromium was not significantly accumulated in the soft tissues upon exposure. In contrast, 65Cu and 106Cd assimilation was detectable for most experimental snails, i.e., 65/63Cu and 106/114Cd ratios in exposed snails were higher than those for controls. Food IR during the labelled feeding phase was 0.16 ?? 0.07 g g-1 d-1. IR was inferred from the amount of 53Cr egested in the feces during depuration and the concentration of 53Cr in the labelled lettuce. Assimilation efficiencies (??95% CI) determined using mass balance calculations were 84 ?? 4% for Cu and 85 ?? 3% for Cd. The ratio method yields similar AE estimates. Expanding the application of this novel stable isotope tracer technique to other metals in a wide variety of species will provide unique opportunities to evaluate the interplay between digestive processes and dietary influx of metals. Understanding the biological processes that modulate dietborne metal uptake is crucial to assess the toxicity of dietborne metals. ?? 2007 Elsevier B.V. All rights reserved.

  4. Coupling heat and chemical tracer experiments for estimating heat transfer parameters in shallow alluvial aquifers.

    Science.gov (United States)

    Wildemeersch, S; Jamin, P; Orban, P; Hermans, T; Klepikova, M; Nguyen, F; Brouyère, S; Dassargues, A

    2014-11-15

    Geothermal energy systems, closed or open, are increasingly considered for heating and/or cooling buildings. The efficiency of such systems depends on the thermal properties of the subsurface. Therefore, feasibility and impact studies performed prior to their installation should include a field characterization of thermal properties and a heat transfer model using parameter values measured in situ. However, there is a lack of in situ experiments and methodology for performing such a field characterization, especially for open systems. This study presents an in situ experiment designed for estimating heat transfer parameters in shallow alluvial aquifers with focus on the specific heat capacity. This experiment consists in simultaneously injecting hot water and a chemical tracer into the aquifer and monitoring the evolution of groundwater temperature and concentration in the recovery well (and possibly in other piezometers located down gradient). Temperature and concentrations are then used for estimating the specific heat capacity. The first method for estimating this parameter is based on a modeling in series of the chemical tracer and temperature breakthrough curves at the recovery well. The second method is based on an energy balance. The values of specific heat capacity estimated for both methods (2.30 and 2.54MJ/m(3)/K) for the experimental site in the alluvial aquifer of the Meuse River (Belgium) are almost identical and consistent with values found in the literature. Temperature breakthrough curves in other piezometers are not required for estimating the specific heat capacity. However, they highlight that heat transfer in the alluvial aquifer of the Meuse River is complex and contrasted with different dominant process depending on the depth leading to significant vertical heat exchange between upper and lower part of the aquifer. Furthermore, these temperature breakthrough curves could be included in the calibration of a complex heat transfer model for

  5. Evaluation of a Public Health Emergency of National Concern using Tracer Methodology

    Directory of Open Access Journals (Sweden)

    Gilberto Ferreira de SOUSA

    2013-09-01

    Full Text Available Este artigo tem o objetivo de descrever a experiência da utilização da metodologia tracer para avaliação do fluxo de informação adotado pelo Centro Nacional de Informações Estratégicas em Vigilância em Saúde (CIEVS para acompanhamento de uma Emergência de Saúde Pública de Importância Nacional (ESPIN no ano de 2010. Durante a realização de pesquisa avaliativa do centro, foi selecionada uma ESPIN como evento traçador e o fluxo percorrido pelas informações foi monitorado durante sua permanência como ponto de discussão no Comitê Permanente (CP. O evento estudado foi um desastre natural (inundação ocorrido no estado de Alagoas e capturado pelo CIEVS na imprensa e confirmado pelo CIEVS parte no estado 48 h depois. O evento passou pelo Instrumento de Decisão sendo considerado uma ESPIN e inserido no monitor CIEVS na Lista de Eventos de Verificação para monitoramento pelo CP. Durante três meses a ESPIN foi acompanhada sendo 180.000 pessoas acometidas com 37 mortes, 17 casos de leptospirose e 175 de dengue confirmados. A metodologia tracer se mostrou instrumento útil para se para se evidenciar a passagem do evento marcador em tempo real pelas diferentes etapas do sistema vigilância em saúde, podendo ser utilizado de maneira complementar nos estudos de avaliação.

  6. Evaluation of Nonferrous Metals as Potential In Vivo Tracers of Transferrin-Based Therapeutics

    Science.gov (United States)

    Zhao, Hanwei; Wang, Shunhai; Nguyen, Son N.; Elci, S. Gokhan; Kaltashov, Igor A.

    2016-02-01

    Transferrin (Tf) is a promising candidate for targeted drug delivery. While development of such products is impossible without the ability to monitor biodistribution of Tf-drug conjugates in tissues and reliable measurements of their levels in blood and other biological fluids, the presence of very abundant endogenous Tf presents a significant impediment to such efforts. Several noncognate metals have been evaluated in this work as possible tracers of exogenous transferrin in complex biological matrices using inductively coupled plasma mass spectrometry (ICP MS) as a detection tool. Placing Ni(II) on a His-tag of recombinant Tf resulted in formation of a marginally stable protein-metal complex, which readily transfers the metal to ubiquitous physiological scavengers, such as serum albumin. An alternative strategy targeted iron-binding pockets of Tf, where cognate Fe(III) was replaced by metal ions known to bind this protein. Both Ga(III) and In(III) were evaluated, with the latter being vastly superior as a tracer (stronger binding to Tf unaffected by the presence of metal scavengers and the retained ability to associate with Tf receptor). Spiking serum with indium-loaded Tf followed by ICP MS detection demonstrated that protein quantities as low as 0.04 nM can be readily detected in animal blood. Combining laser ablation with ICP MS detection allows distribution of exogenous Tf to be mapped within animal tissue cross-sections with spatial resolution exceeding 100 μm. The method can be readily extended to a range of other therapeutics where metalloproteins are used as either carriers or payloads.

  7. Binary Schemes of Vapor Bubble Growth

    Science.gov (United States)

    Zudin, Yu. B.

    2015-05-01

    A problem on spherically symmetric growth of a vapor bubble in an infi nite volume of a uniformly superheated liquid is considered. A description of the limiting schemes of bubble growth is presented. A binary inertial-thermal bubble growth scheme characterized by such specifi c features as the "three quarters" growth law and the effect of "pressure blocking" in a vapor phase is considered.

  8. Vapor Pressure of 2-Chlorovinyl Dichloroarsine (Lewisite)

    Science.gov (United States)

    2009-02-01

    Streams of Compounds for Determining Vapor Pressure 11 3. Vapor Pressure of Lewisite I from Multiple Sources: Conant, Sumner, Lewis, Keyes, Price ...number of publications in the open literature by Green and Price ,4 Lewis and Perkins,5 Mann and Pope, Mohler and Polya7 and Gibson and Johnson.8...point. (2) Banks et al.,14 reported that during the fractional distillation of the reaction products of phenyl dichloroarsine and acetylene , 2

  9. Oxidation Kinetics of Chemically Vapor-Deposited Silicon Carbide in Wet Oxygen

    Science.gov (United States)

    Opila, Elizabeth J.

    1994-01-01

    The oxidation kinetics of chemically vapor-deposited SiC in dry oxygen and wet oxygen (P(sub H2O) = 0.1 atm) at temperatures between 1200 C and 1400 C were monitored using thermogravimetric analysis. It was found that in a clean environment, 10% water vapor enhanced the oxidation kinetics of SiC only very slightly compared to rates found in dry oxygen. Oxidation kinetics were examined in terms of the Deal and Grove model for oxidation of silicon. It was found that in an environment containing even small amounts of impurities, such as high-purity Al2O3 reaction tubes containing 200 ppm Na, water vapor enhanced the transport of these impurities to the oxidation sample. Oxidation rates increased under these conditions presumably because of the formation of less protective sodium alumino-silicate scales.

  10. Application of the Spectral Structure Parameterization technique: retrieval of total water vapor columns from GOME

    Directory of Open Access Journals (Sweden)

    R. Lang

    2002-07-01

    Full Text Available We use a recently proposed spectral sampling technique for measurements of atmospheric transmissions called the Spectral Structure Parameterization (SSP in order to retrieve total water vapor columns (WVC from reflectivity spectra measured by the Global Ozone Monitoring Experiment (GOME. SSP provides a good compromise between efficiency and speed when performing retrievals on highly structured spectra of narrow-band absorbers like water vapor. We show that SSP can be implemented in a radiative transfer scheme which treats both direct-path absorption and absorption by singly scattered light directly. For the retrieval we exploit a ro-vibrational overtone band of water vapor located in the visible around 590 nm. We compare our results to independent values given by the data assimilation model of ECMWF. In addition, results are compared to those obtained from the more accurate, but slower, Optical Absorption Coefficient Spectroscopy (OACS.

  11. Application of the Spectral Structure Parameterization technique: retrieval of total water vapor columns from GOME

    Directory of Open Access Journals (Sweden)

    R. Lang

    2003-01-01

    Full Text Available We use a recently proposed spectral sampling technique for measurements of atmospheric transmissions called the Spectral Structure Parameterization (SSP in order to retrieve total water vapor columns (WVC from reflectivity spectra measured by the Global Ozone Monitoring Experiment (GOME. SSP provides a good compromise between efficiency and speed when performing retrievals on highly structured spectra of narrow-band absorbers like water vapor. We show that SSP can be implemented in a radiative transfer scheme which treats both direct-path absorption and absorption by singly-scattered light directly. For the retrieval we exploit a ro-vibrational overtone band of water vapor located in the visible around 590 nm. We compare our results to independent values given by the data assimilation model of ECMWF. In addition, results are compared to those obtained from the more accurate, but more computationally expensive, Optical Absorption Coefficient Spectroscopy (OACS.

  12. Estimation of Contaminant Subslab Concentration in Vapor Intrusion Including Lateral Source–Building Separation

    Science.gov (United States)

    Yao, Yijun; Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2014-01-01

    Most current vapor-intrusion screening models employ the assumption of a subsurface homogenous source distribution, and groundwater data obtained from nearby monitoring wells are usually taken to reflect the source concentration for several nearby buildings. This practice makes it necessary to consider the possible influence of lateral source–building separation. In this study, a new way to estimate subslab (nonbiodegradable) contaminant concentration is introduced that includes the influence of source offset with the help of a conformal transform technique. Results from this method are compared with those from a three-dimensional numerical model. Based on this newly developed method, a possible explanation is provided here for the great variation in the attenuation factors of the soil vapor concentrations of groundwater-to-subslab contaminants found in the EPA vapor-intrusion database. PMID:24795543

  13. Estimation of Contaminant Subslab Concentration in Vapor Intrusion Including Lateral Source-Building Separation.

    Science.gov (United States)

    Yao, Yijun; Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2013-08-01

    Most current vapor-intrusion screening models employ the assumption of a subsurface homogenous source distribution, and groundwater data obtained from nearby monitoring wells are usually taken to reflect the source concentration for several nearby buildings. This practice makes it necessary to consider the possible influence of lateral source-building separation. In this study, a new way to estimate subslab (nonbiodegradable) contaminant concentration is introduced that includes the influence of source offset with the help of a conformal transform technique. Results from this method are compared with those from a three-dimensional numerical model. Based on this newly developed method, a possible explanation is provided here for the great variation in the attenuation factors of the soil vapor concentrations of groundwater-to-subslab contaminants found in the EPA vapor-intrusion database.

  14. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

    Science.gov (United States)

    McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

    2007-09-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

  15. Effects of crude oil on water and tracer movement in the unsaturated and saturated zones

    Science.gov (United States)

    Delin, Geoffrey N.; Herkelrath, William N.

    2017-05-01

    A tracer test was conducted to aid in the investigation of water movement and solute transport at a crude-oil spill site near Bemidji, Minnesota. Time of travel was measured using breakthrough curves for rhodamine WT and bromide tracers moving from the soil surface through oil-contaminated and oil-free unsaturated zones to the saturated zone. Results indicate that the rates of tracer movement were similar in the oil-free unsaturated and saturated zones compared to the oily zones. These results are somewhat surprising given the oil contamination in the unsaturated and saturated zones. Rhodamine tracer breakthrough in the unsaturated and saturated zones in general was delayed in comparison to bromide tracer breakthrough. Peak tracer concentrations for the lysimeters and wells in the oily zone were much greater than at the corresponding depths in the oil-free zone. Water and tracer movement in the oily zone was complicated by soil hydrophobicity and decreased oil saturations toward the periphery of the oil. Preferential flow resulted in reduced tracer interaction with the soil, adsorption, and dispersion and faster tracer movement in the oily zone than expected. Tracers were freely transported through the oily zone to the water table. Recharge calculations support the idea that the oil does not substantially affect recharge in the oily zone. This is an important result indicating that previous model-based assumptions of decreased recharge beneath the oil were incorrect. Results have important implications for modeling the fate and transport of dissolved contaminants at hydrocarbon spill sites.

  16. Development of Models to Simulate Tracer Tests for Characterization of Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Mark D.; Reimus, Paul; Vermeul, Vincent R.; Rose, Peter; Dean, Cynthia A.; Watson, Tom B.; Newell, D.; Leecaster, Kevin; Brauser, Eric

    2013-05-01

    A recent report found that power and heat produced from enhanced (or engineered) geothermal systems (EGSs) could have a major impact on the U.S energy production capability while having a minimal impact on the environment. EGS resources differ from high-grade hydrothermal resources in that they lack sufficient temperature distribution, permeability/porosity, fluid saturation, or recharge of reservoir fluids. Therefore, quantitative characterization of temperature distributions and the surface area available for heat transfer in EGS is necessary for the design and commercial development of the geothermal energy of a potential EGS site. The goal of this project is to provide integrated tracer and tracer interpretation tools to facilitate this characterization. This project was initially focused on tracer development with the application of perfluorinated tracer (PFT) compounds, non-reactive tracers used in numerous applications from atmospheric transport to underground leak detection, to geothermal systems, and evaluation of encapsulated PFTs that would release tracers at targeted reservoir temperatures. After the 2011 midyear review and subsequent discussions with the U.S. Department of Energy Geothermal Technology Program (GTP), emphasis was shifted to interpretive tool development, testing, and validation. Subsurface modeling capabilities are an important component of this project for both the design of suitable tracers and the interpretation of data from in situ tracer tests, be they single- or multi-well tests. The purpose of this report is to describe the results of the tracer and model development for simulating and conducting tracer tests for characterizing EGS parameters.

  17. Journal: A Review of Some Tracer-Test Design Equations for ...

    Science.gov (United States)

    Determination of necessary tracer mass, initial sample-collection time, and subsequent sample-collection frequency are the three most difficult aspects to estimate for a proposed tracer test prior to conducting the tracer test. To facilitate tracer-mass estimation, 33 mass-estimation equations are reviewed here, 32 of which were evaluated using previously published tracer-test design examination parameters. Comparison of the results produced a wide range of estimated tracer mass, but no means is available by which one equation may be reasonably selected over the others. Each equation produces a simple approximation for tracer mass. Most of the equations are based primarily on estimates or measurements of discharge, transport distance, and suspected transport times. Although the basic field parameters commonly employed are appropriate for estimating tracer mass, the 33 equations are problematic in that they were all probably based on the original developers' experience in a particular field area and not necessarily on measured hydraulic parameters or solute-transport theory. Suggested sampling frequencies are typically based primarily on probable transport distance, but with little regard to expected travel times. This too is problematic in that tends to result in false negatives or data aliasing. Simulations from the recently developed efficient hydrologic tracer-test design methodology (EHTD) were compared with those obtained from 32 of the 33 published tracer-

  18. Pure component vapor pressures of organic isomers

    Science.gov (United States)

    Dang, Caroline; Bannan, Thomas; Topping, David

    2017-04-01

    Atmospheric aerosols affect the Earth's climate directly through light scattering and absorption as well as indirectly by affecting cloud formation. There are many unanswered questions about how material properties of organic aerosols affect the climate. Predicting the formation of secondary organic aerosol (SOA), arising from gas to particle partitioning of potentially millions of compounds, remains one of the most challenging aspects in this regards. Of particular importance on predicting SOA formation is the saturation vapor pressure of each component. This property is typically obtained from group contribution methods (GCMs). However, it is currently unclear as to what level of accuracy is required or attainable from such techniques. Researchers have recently been able to measure low vapor pressures (lower limit of 10-8 Pa) experimentally using various techniques, and the University of Manchester Knudsen Effusion Mass Spectrometer (KEMS) has previously been used to measure vapor pressure of low volatility organics. Our recent KEMS work shows that functional group positioning has an effect on vapor pressure that is not accurately captured with estimation methods, and that experimental vapor pressures are 1-4 orders of magnitudes lower than predictive techniques. This has atmospheric impact through the variable amount of organic aerosol that is predicted to condense. In this study we present new measurements from the KEMS that can then be used to refine different experimental vapor pressure techniques as well as to provide data sets for building regression models to improve current predictive techniques.

  19. Bioeffects due to acoustic droplet vaporization

    Science.gov (United States)

    Bull, Joseph

    2015-11-01

    Encapsulated micro- and nano-droplets can be vaporized via ultrasound, a process termed acoustic droplet vaporization. Our interest is primarily motivated by a developmental gas embolotherapy technique for cancer treatment. In this methodology, infarction of tumors is induced by selectively formed vascular gas bubbles that arise from the acoustic vaporization of vascular microdroplets. Additionally, the microdroplets may be used as vehicles for localized drug delivery, with or without flow occlusion. In this talk, we examine the dynamics of acoustic droplet vaporization through experiments and theoretical/computational fluid mechanics models, and investigate the bioeffects of acoustic droplet vaporization on endothelial cells and in vivo. Early timescale vaporization events, including phase change, are directly visualized using ultra-high speed imaging, and the influence of acoustic parameters on droplet/bubble dynamics is discussed. Acoustic and fluid mechanics parameters affecting the severity of endothelial cell bioeffects are explored. These findings suggest parameter spaces for which bioeffects may be reduced or enhanced, depending on the objective of the therapy. This work was supported by NIH grant R01EB006476.

  20. Characteristics of water vapor fluctuations by the use of GNSS signal delays

    Science.gov (United States)

    Gregorič, Asta; Škrlec, Samo; Mole, Maruška; Bergant, Klemen; Vučković, Marko; Stanič, Samo

    2017-04-01

    Water vapor plays a crucial role in a number of atmospheric processes related to the water cycle. It is also the Earth's most abundant greenhouse gas, thus influencing global climate as well as micrometeorology. Since the phase change of water is associated with large latent heat, water vapor plays an important role in the vertical atmospheric stability. It also influences aerosol aging and removal from the atmosphere. As the temporal and spatial distribution of water vapor is in general highly variable, continuous monitoring at several locations is required to be able to describe the situation in a given terrain configuration. In-situ meteorological measurements provide the information on water vapor concentration at the surface only, while the radiosonde data suffers from poor temporal and spatial (horizontal) resolution. Integrated water vapor content above a certain location on the surface can also be monitored in real time, exploiting the wet delay of GNSS signals, however, it does not yield absolute humidity. In this contribution we present a measurement of average absolute humidity within the Vipava valley (Slovenia), between February 2015 and October 2016. It is based on differential measurement of integrated water vapor content at two adjacent stations, using stationary GNSS receivers, which are horizontally displaced for 6 km, and vertically displaced for 826 m. The integrated water vapor values were derived using the GIPSY-OASIS II software. One of the receivers is located at the valley floor (125 m a.s.l.) and the other on the top of the adjacent mountain ridge (951 m a.s.l.). Visual data from both stations was also stored to evaluate the reliability of the remote sensing results in different weather conditions. Based on the dataset covering 20 consecutive months, we investigated temporal evolution of the water vapor content within the valley. The results show typical seasonal pattern and are strongly correlated to weather phenomena. Comparison to the

  1. Technical Note: Coupling of chemical processes with the Modular Earth Submodel System (MESSy submodel TRACER

    Directory of Open Access Journals (Sweden)

    P. Jöckel

    2007-11-01

    Full Text Available The implementation of processes related to chemistry into Earth System Models and their coupling within such systems requires the consistent description of the chemical species involved. We provide a tool (written in Fortran95 to structure and manage information about constituents, herein after referred to as tracers, namely the Modular Earth Submodel System (MESSy generic (i.e., infrastructure submodel TRACER. With TRACER it is possible to define a multitude of tracer sets, depending on the spatio-temporal representation (i.e., the grid structure of the model. The required information about a specific chemical species is split into the static meta-information about the characteristics of the species, and its (generally in time and space variable abundance in the corresponding representation. TRACER moreover includes two submodels. One is TRACER_FAMILY, an implementation of the tracer family concept. It distinguishes between two types: type-1 families are usually applied to handle strongly related tracers (e.g., fast equilibrating species for a specific process (e.g., advection. In contrast to this, type-2 families are applied for tagging techniques, in which specific species are artificially decomposed and associated with additional information, in order to conserve the linear relationship between the family and its members. The second submodel is TRACER_PDEF, which corrects and budgets numerical negative overshoots that arise in many process implementations due to the numerical limitations (limited precision, rounding errors. The submodel therefore guarantees the positive definiteness of the tracers and stabilises the integration scheme. As a by-product, it further provides a global tracer mass diagnostic. Last but not least, we present the submodel PTRAC for the definition of prognostic tracers via a Fortran95 namelist. TRACER with its submodels and PTRAC can readily be applied to a variety of models without further requirements. The code and

  2. A tracer-based inversion method for diagnosing eddy-induced diffusivity and advection

    Science.gov (United States)

    Bachman, S. D.; Fox-Kemper, B.; Bryan, F. O.

    2015-02-01

    A diagnosis method is presented which inverts a set of tracer flux statistics into an eddy-induced transport intended to apply for all tracers. The underlying assumption is that a linear flux-gradient relationship describes eddy-induced tracer transport, but a full tensor coefficient is assumed rather than a scalar coefficient which allows for down-gradient and skew transports. Thus, Lagrangian advection and anisotropic diffusion not necessarily aligned with the tracer gradient can be diagnosed. In this method, multiple passive tracers are initialized in an eddy-resolving flow simulation. Their spatially-averaged gradien