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Sample records for traces mass lensperfect

  1. Trace amount analysis using spark mass spectrometry

    International Nuclear Information System (INIS)

    Stefani, Rene

    1975-01-01

    Characteristics of spark mass spectrometers (ion source, properties of the ion beam, ion optics, and performance) and their use in qualitative and quantitative analysis are described. This technique is very interesting for the semi-quantitative analysis of trace amounts, down to 10 -8 atoms. Examples of applications such as the analysis of high purity materials and non-conducting mineral samples, and determination of carbon and gas trace amounts are presented. (50 references) [fr

  2. Contour tracing for segmentation of mammographic masses

    International Nuclear Information System (INIS)

    Elter, Matthias; Held, Christian; Wittenberg, Thomas

    2010-01-01

    CADx systems have the potential to support radiologists in the difficult task of discriminating benign and malignant mammographic lesions. The segmentation of mammographic masses from the background tissue is an important module of CADx systems designed for the characterization of mass lesions. In this work, a novel approach to this task is presented. The segmentation is performed by automatically tracing the mass' contour in-between manually provided landmark points defined on the mass' margin. The performance of the proposed approach is compared to the performance of implementations of three state-of-the-art approaches based on region growing and dynamic programming. For an unbiased comparison of the different segmentation approaches, optimal parameters are selected for each approach by means of tenfold cross-validation and a genetic algorithm. Furthermore, segmentation performance is evaluated on a dataset of ROI and ground-truth pairs. The proposed method outperforms the three state-of-the-art methods. The benchmark dataset will be made available with publication of this paper and will be the first publicly available benchmark dataset for mass segmentation.

  3. Determination of trace and ultra-trace elements in Dergaon meteorite by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Balaram, V.; Gnaneswara Rao, T.; Anjaiah, K.V.; Phukon, N.; Majumdar, A.C.

    2003-01-01

    In this paper, a detailed methodology for high precision measurement of several trace and ultra-trace elements including REE and PGE have been presented using effective sample preparation techniques and inductively coupled plasma mass spectrometry. Discussion is focussed on aspects, such as total dissolution and recovery of all elements, minimization of oxide and doubly-charged and other polyatomic ion interferences, calibration by matrix matching standards, accuracy and precision

  4. Using the minimum spanning tree to trace mass segregation

    NARCIS (Netherlands)

    Allison, R.J.; Goodwin, S.P.; Parker, R.J.; Portegies Zwart, S.F.; de Grijs, R.; Kouwenhoven, M.B.N.

    2009-01-01

    We present a new method to detect and quantify mass segregation in star clusters. It compares the minimum spanning tree (MST) of massive stars with that of random stars. If mass segregation is present, the MST length of the most massive stars will be shorter than that of random stars. This

  5. Tracing Low-Mass Star Formation in the Magellanic Clouds

    Science.gov (United States)

    Petr-Gotzens, Monika; Zivkov, V.; Oliveira, J.

    2017-06-01

    Star formation in low metallicity environments is evidently occurring under different conditions than in our Milky Way. Lower metallicity implies a lower dust to gas ratio, most likely leading to less cooling efficiency at high density molecular cores where low mass stars are expected to form. We outline a project that aims to identify the low mass pre-main sequence populations within the Large and Small Magellanic Cloud. We developed an automatic detection algorithm that systematically analyses near-infrared colour-magnitude diagrammes constructed from the VMC (VISTA Magellanic Clouds) public survey data. In this poster we present our first results that show that we are able to detect significant numbers of PMS stars with masses down to 1.5 solar mass.

  6. Analysis of trace gases at ppb levels by proton transfer reaction mass spectrometry (PTR-MS)

    International Nuclear Information System (INIS)

    Lindinger, W.; Hansel, A.

    1996-01-01

    A proton transfer reaction mass spectrometry (PTR-MS) system has been developed which allows for on-line measurements of trace gas components with concentrations as low as 1 ppb. The method is based on reactions of H 3 O + ions, which perform non-dissociative proton transfer to most of the common organic trace constituents but do not react with any of the components present in clean air. Examples of medical information obtained by means of breath analysis, of environmental trace analysis, and examples in the field of food chemistry demonstrate the wide applicability of the method. (Authors)

  7. Mass spectrometric methods for trace analysis of metals

    International Nuclear Information System (INIS)

    Bahr, U.; Schulten, H.R.

    1981-01-01

    A brief outline is given of the principles of mass spectrometry (MS) and the fundamentals of qualitative and quantitative mass spectrometric analysis emphasizing recent developments and results. Classical methods of the analysis of solids, i.e. spark-source MS and thermal ionization MS, as well as recent methods of metal analysis are described. Focal points in this survey of recently developed techniques include secondary ion MS, laser probe MS, plasma ion source MS, gas discharge MS and field desorption MS. Here, a more detailed description is given and the merits of these emerging methods are discussed more explicitly. In particular, the results of the field desorption techniques in elemental analyses are reviewed and critically evaluated

  8. Applications of mass spectrometry in the trace element analysis of biological materials

    International Nuclear Information System (INIS)

    Moens, L.

    1997-01-01

    The importance of mass spectrometry for the analysis of biological material is illustrated by reviewing the different mass spectrometric methods applied and describing some typical applications published recently. Though atomic absorption spectrometry is used in the majority of analyses of biological material, most mass spectrometric methods have been used to some extent for trace element determination in biomedical research. The relative importance of the different methods is estimated by reviewing recent research papers. It is striking that especially inductively coupled plasma mass spectrometry is increasingly being applied, partly because the method can be used on-line after chromatographic separation, in speciation studies. Mass spectrometric methods prove to offer unique possibilities in stable isotope tracer studies and for this purpose also experimentally demanding methods such as thermal ionization mass spectrometry and accelerator mass spectrometry are frequently used. (orig.)

  9. Determination of trace amounts of impurities in molybdenum by spark source and glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa

    1994-01-01

    For the determination of trace and ultra-trace amounts of impurities in high-purity molybdenum, spark source mass spectrometry and glow discharge mass spectrometry were studied. In spark source mass spectrometry using the metal probe method, the liquid-helium cryogenic pump was used in order to protect the surface of the samples from oxidation. The theoretical relative sensitivity factors (Mo=1) calculated from physical properties were used. The analytical results obtained for molybdenum tablet and high-purity molybdenum were in good agreement with those obtained by other methods (atomic absorption spectrometry and others). In glow discharge mass spectrometry, the relative sensitivity factors were calculated by using the results obtained by spark source mass spectrometry and atomic absorption spectrometry, and this method was applied to the determination of ultra-trace amounts of impurities in ultra high-purity molybdenum and gave the satisfactory results. The detection limits (2σ, n=10) in the integration time of 600 s for U and Th were 0.6 ppb and 0.3 ppb, and the values for Al, Si, Cr, Mn and Cu were in the range of 10 ppb to 0.5 ppb. (author)

  10. The total trace element content of some Scottish soils by spark source mass spectrometry

    International Nuclear Information System (INIS)

    Ure, A.M.; Bacon, J.R.; Berrow, M.L.; Watt, J.J.

    1979-01-01

    Quantitative methods of analysis by spark source mass spectrometry have been used to determine the total trace element content of the surface horizons of 10 arable Scottish soils derived from parent materials of different geological origin and used for earlier trace element surveys. Other methods have been used to supplement these analyses for 12 elements including the major elements, and results for a total of 62 elements in the 10 soils are reported. The results are discussed in terms of the geological nature of the soil parent material making use of 62-element soil fingerprints for visual comparison. It is concluded that the total trace element contents of a Scottish soil corresponds to that expected on the basis of the geochemistry of its parent materials and that the influence of agricultural operations on soil contents is of secondary importance. Average soil contents for most elements are closely similar to published values for crustal abundance. (Auth.)

  11. Analysis of trace elements by means of accelerator secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    Ender, R.M.

    1997-01-01

    The analysis of material composition and trace element concentration is of increasing interest primarily in semiconductor technology but also in metallurgy, geology, biology and medicine. At present, Secondary Ion Mass Spectrometry (SIMS) is in many respects the best technique to provide 3-dimensional information on the distribution of trace elements with concentrations below 1 ppm. However, due to the presence of molecular ions the detectability of many trace elements it restricted because of molecular mass interferences. In addition, detectors used in SIMS have a background counting rate of 0.1-1 Hz, which further limits trace element analysis. In Accelerator Mass Spectrometry (AMS) long-lived radionuclides are detected free of molecular interferences and detector background at isotopic ratios as low as 10 -15 . Moreover, isobaric interferences can be reduced as well. In order to benefit from these advantages a combination of SIMS and AMS (Accelerator SIMS) has been proposed almost 20 years ago, but no facility has ever been fully developed. It has been the aim of this work to add a new sputtering chamber for AMS measurements of ultrapure semiconductor material to the existing PSI/ETH AMS facility. To fulfill the requirements of material analysis, an UHV chamber with special precautions against contamination has been built and adapted to the existing AMS setup. For sputtering, a commercial Cs gun with an ExB filter and a 1 o beam bend for neutral particle suppression is used to obtain a pure Cs ion beam. The gun is equipped with different apertures for varying the diameter of the beam spot. With the integrated scanning unit the 10 keV Cs beam can be rastered over approximately 1 mm 2 . This allows different applications such as bulk analysis, depth profiling and imaging. The secondary ion extraction is matched to the ion optical and geometrical requirements of the existing accelerator mass spectrometer. (author) figs., tabs., 67 refs

  12. Status of the naval research laboratory trace element accelerator mass spectrometer: Characterization of the Pretzel magnet

    Science.gov (United States)

    Knies, D. L.; Grabowski, K. S.; Hubler, G. K.; Treacy, D. J.; DeTurck, T. M.; Enge, H. A.

    1997-02-01

    A novel design for a trace element accelerator mass spectrometer has been developed at the Naval Research Laboratory and is now under construction. It will allow parallel analysis of a broad range of impurities in electronic, biological, and geological materials. The system includes a modified commercial secondary ion mass spectrometer (Physical Electronics, model 6300) as the source of secondary ions, a recombinator consisting of a Pretzel magnet that serves as a tunable notch mass filter, a 3MV Pelletron tandem accelerator, a large electrostatic analyzer, and a split-pole magnetic spectrograph with a 1.5-m-long focal plane. All other ion optical and steering elements are electrostatic, to maintain parallel transmission of different mass species. This paper summarizes the design concept, and describes in some detail the characteristics of the Pretzel magnet.

  13. Mass fractions of 52 trace elements and zinc/trace element content ratios in intact human prostates investigated by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Zaichick, Sofia; Zaichick, Vladimir; Nosenko, Sergey; Moskvina, Irina

    2012-11-01

    Contents of 52 trace elements in intact prostate of 64 apparently healthy 13-60-year-old men (mean age 36.5 years) were investigated by inductively coupled plasma mass spectrometry. Mean values (M ± SΕΜ) for mass fraction (in milligrams per kilogram, on dry-weight basis) of trace elements were as follows: Ag 0.041 ± 0.005, Al 36 ± 4, Au 0.0039 ± 0.0007, B 0.97 ± 0.13, Be 0.00099 ± 0.00006, Bi 0.021 ± 0.008, Br 29 ± 3, Cd 0.78 ± 0.09, Ce 0.028 ± 0.004, Co 0.035 ± 0.003, Cs 0.034 ± 0.003, Dy 0.0031 ± 0.0005, Er 0.0018 ± 0.0004, Gd 0.0030 ± 0.0005, Hg 0.046 ± 0.006, Ho 0.00056 ± 0.00008, La 0.074 ± 0.015, Li 0.040 ± 0.004, Mn 1.53 ± 0.09, Mo 0.30 ± 0.03, Nb 0.0051 ± 0.0009, Nd 0.013 ± 0.002, Ni 4.3 ± 0.7, Pb 1.8 ± 0.4, Pr 0.0033 ± 0.0004, Rb 15.9 ± 0.6, Sb 0.040 ± 0.005, Se 0.73 ± 0.03, Sm 0.0027 ± 0.0004, Sn 0.25 ± 0.05, Tb 0.00043 ± 0.00009, Th 0.0024 ± 0.0005, Tl 0.0014 ± 0.0001, Tm 0.00030 ± 0.00006, U 0.0049 ± 0.0014, Y 0.019 ± 0.003, Yb 0.0015 ± 0.0002, Zn 782 ± 97, and Zr 0.044 ± 0.009, respectively. The upper limit of mean contents of As, Cr, Eu, Ga, Hf, Ir, Lu, Pd, Pt, Re, Ta, and Ti were the following: As ≤ 0.018, Cr ≤ 0.64, Eu ≤ 0.0006, Ga ≤ 0.08, Hf ≤ 0.02, Ir ≤ 0.0004, Lu ≤ 0.00028, Pd ≤ 0.007, Pt ≤ 0.0009, Re ≤ 0.0015, Ta ≤ 0.005, and Ti ≤ 2.6. In all prostate samples, the content of Te was under detection limit (element contents as well as correlations between Zn and trace elements were calculated. Our data indicate that the human prostate accumulates such trace elements as Al, Au, B, Br, Cd, Cr, Ga, Li, Mn, Ni, Pb, U, and Zn. No special relationship between Zn and other trace elements was found.

  14. Point Movement Trace Vs. The Range Of Mining Exploitation Effects In The Rock Mass

    Science.gov (United States)

    Sroka, Anton; Knothe, Stanisław; Tajduś, Krzysztof; Misa, Rafał

    2015-12-01

    The geometric-integral theories of the rock mass point movements due to mining exploitation assume the relationship between the progress of subsidence and horizontal movement. By analysing the movement trace of a point located on the surface, and the influence of the mining exploitation in the rock mass, an equation describing the relationship between the main components of the deformation conditions was formulated. The result is consistent with the in situ observations and indicates the change of the rock mass component volume due to mining exploitation. The analyses and in situ observations demonstrate clearly that the continuity equation adopted in many solutions in the form: sumlimits_{i = 1}^{i = 3} {\\varepsilon _{ii}= 0} is fundamentally incorrect.

  15. Recent Developments in Trace, Ultratrace and Isotope Ratio Measurements in Inductively Coupled Plasma Mass Spectrometry

    International Nuclear Information System (INIS)

    Zahran, N. F.

    2004-01-01

    Inductively coupled plasma mass spectrometry (ICP-MS) and Laser Ablation (LA-ICP-MS) are recent techniques for trace, ultratrace and isotope ratio measurements. Main features of these techniques and their figure of merit and capabilities are discussed. An overview of ICP-MS instrument is presented in addition to its precision, accuracy and detection limits. Uses of ICP-MS in environmental monitoring in some cases for detection of some radio nuclides are presented. Two geological applications namely, zircon grains analysis and age dating of Rb-Sr method are presented. Zn elemental and isotopic analyses in blood and serum as a biological application is shown. (Author)

  16. Desorption electrospray ionization mass spectrometry for trace analysis of agrochemicals in food.

    Science.gov (United States)

    García-Reyes, Juan F; Jackson, Ayanna U; Molina-Díaz, Antonio; Cooks, R Graham

    2009-01-15

    Desorption electrospray ionization (DESI) is applied to the rapid, in situ, direct qualitative and quantitative (ultra)trace analysis of agrochemicals in foodstuffs. To evaluate the potential of DESI mass spectrometry (MS) in toxic residue testing in food, 16 representative multiclass agricultural chemicals (pesticides, insecticides, herbicides, and fungicides) were selected (namely, ametryn, amitraz, azoxystrobin, bitertanol, buprofezin, imazalil, imazalil metabolite, isofenphos-methyl, malathion, nitenpyram, prochloraz, spinosad, terbuthylazine, thiabendazole, and thiacloprid). The DESI-MS experiments were performed using 3 microL of solution spotted onto conventional smooth poly(tetrafluoroethylene) (PTFE) surfaces, with examination by MS and tandem mass spectrometry (MS/MS) using an ion trap mass spectrometer. Optimization of the spray solvent led to the use of acetonitrile/water (80:20) (v/v), with 1% formic acid. Most of the compounds tested showed remarkable sensitivity in the positive ion mode, approaching that attainable with conventional direct infusion electrospray mass spectrometry. To evaluate the potential of the proposed approach in real samples, different experiments were performed including the direct DESI-MS/MS analysis of fruit peels and also of fruit/vegetable extracts. The results proved that DESI allows the detection and confirmation of traces of agrochemicals in actual market-purchased samples. In addition, MS/MS confirmation of selected pesticides in spiked vegetable extracts was obtained at absolute levels as low as 1 pg for ametryn. Quantitation of imazalil residues was also undertaken using an isotopically labeled standard. The data obtained were in agreement with those from the liquid chromatography mass spectrometry (LC-MS) reference method, with relative standard deviation (RSD) values consistently below 15%. The results obtained demonstrate the sensitivity of DESI as they meet the stringent European Union pesticide regulation

  17. Diode laser based resonance ionization mass spectrometry for spectroscopy and trace analysis of uranium isotopes

    International Nuclear Information System (INIS)

    Hakimi, Amin

    2013-01-01

    In this doctoral thesis, the upgrade and optimization of a diode laser system for high-resolution resonance ionization mass spectrometry is described. A frequency-control system, based on a double-interferometric approach, allowing for absolute stabilization down to 1 MHz as well as frequency detunings of several GHz within a second for up to three lasers in parallel was optimized. This laser system was used for spectroscopic studies on uranium isotopes, yielding precise and unambiguous level energies, total angular momenta, hyperfine constants and isotope shifts. Furthermore, an efficient excitation scheme which can be operated with commercial diode lasers was developed. The performance of the complete laser mass spectrometer was optimized and characterized for the ultra-trace analysis of the uranium isotope 236 U, which serves as a neutron flux dosimeter and tracer for radioactive anthropogenic contaminations in the environment. Using synthetic samples, an isotope selectivity of ( 236 U)/( 238 U) = 4.5(1.5) . 10 -9 was demonstrated.

  18. Development of the heat and mass transfer model for the study of the temperature traces water droplets in a flame

    Directory of Open Access Journals (Sweden)

    Antonov Dmitry

    2017-01-01

    Full Text Available The heat and mass transfer model is developed with using Ansys Fluent. The typical temperature of gases in the trace of water droplets is determined (initial temperature of gases 1170 К. Several types for the location of water droplets are studied: two successive water droplets; two parallel water droplets; five water droplets in checkerboard order. The hypothesis about gas temperature reduction in the trace of a moving liquid is confirmed.

  19. Development of the heat and mass transfer model for the study of the temperature traces water droplets in a flame

    OpenAIRE

    Antonov Dmitry; Kostomarov Petr

    2017-01-01

    The heat and mass transfer model is developed with using Ansys Fluent. The typical temperature of gases in the trace of water droplets is determined (initial temperature of gases 1170 К). Several types for the location of water droplets are studied: two successive water droplets; two parallel water droplets; five water droplets in checkerboard order. The hypothesis about gas temperature reduction in the trace of a moving liquid is confirmed.

  20. Design of a compact permanent magnet Cyclotron Mass Spectrometer for the detection and measurement of trace isotopes

    International Nuclear Information System (INIS)

    Young, A.T.; Bertsche, K.J.; Clark, D.J.; Halbach, K.; Kunkel, W.B.; Leung, K.N.; Li, C.Y.

    1992-07-01

    A technique for the detection of trace amounts of rare isotopes, Cyclotron mass Spectrometry (CMS), is described. This technique uses the relationships between particle mass, charge, magnetic field strength and cyclotron orbital frequency to provide high mass resolution. The instrument also has high sensitivity and is capable of measuring isotopes with abundances of - 12 . Improvements now being implemented will lead to further increases in the sensitivity and enhance operating parameters such as cost, portability, and sample throughput

  1. An industry-scale mass marking technique for tracing farmed fish escapees.

    Directory of Open Access Journals (Sweden)

    Fletcher Warren-Myers

    Full Text Available Farmed fish escape and enter the environment with subsequent effects on wild populations. Reducing escapes requires the ability to trace individuals back to the point of escape, so that escape causes can be identified and technical standards improved. Here, we tested if stable isotope otolith fingerprint marks delivered during routine vaccination could be an accurate, feasible and cost effective marking method, suitable for industrial-scale application. We tested seven stable isotopes, (134Ba, (135Ba, (136Ba, (137Ba, (86Sr, (87Sr and (26Mg, on farmed Atlantic salmon reared in freshwater, in experimental conditions designed to reflect commercial practice. Marking was 100% successful with individual Ba isotopes at concentrations as low as 0.001 µg. g-1 fish and for Sr isotopes at 1 µg. g-1 fish. Our results suggest that 63 unique fingerprint marks can be made at low cost using Ba (0.0002 - 0.02 $US per mark and Sr (0.46 - 0.82 $US per mark isotopes. Stable isotope fingerprinting during vaccination is feasible for commercial application if applied at a company level within the world's largest salmon producing nations. Introducing a mass marking scheme would enable tracing of escapees back to point of origin, which could drive greater compliance, better farm design and improved management practices to reduce escapes.

  2. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H

    2005-12-15

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here.

  3. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    International Nuclear Information System (INIS)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H.

    2005-12-01

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here

  4. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-456 Marine Sediment Samples

    International Nuclear Information System (INIS)

    2016-01-01

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact of large coastal cities on marine ecosystems is an issue of prime concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. The IAEA Environment Laboratories has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of a reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance, quality control and associated good laboratory practice are essential components of all marine environmental monitoring studies. Quality control procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess t h e reliability and comparability of measurement data. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. A marine sediment sample with certified mass amount contents for aluminium, arsenic, cadmium chromium, cobalt, copper, iron, lead, mercury, methyl mercury, manganese, nickel, vanadium and zinc was recently produced by the IAEA Environment Laboratories. This publication presents the sample preparation methodology, including material homogeneity and the stability study, the selection of laboratories, the evaluation of results from the certification campaign, and the assignment of property values and their associated uncertainty. As a result, certified values for mass fractions and associated expanded uncertainty were

  5. Trace element determinations in uranium bearing minerals and rocks by spark source mass spectrometry

    International Nuclear Information System (INIS)

    Luck, J.; Szacki, W.; Pluhar, E.

    1981-01-01

    Spark source mass spectrometry has been used in the multielemental analyses in the samples: BIR, DNC, and W-2 of the U.S. Geological Survey (USGS). The concentrations for up to 23 trace elements could be determined depending on the concentration level and matrix composition. The USGS standards W-1 and BCR-1 were used as multi-elemental standards to evaluate the necessary sensitivity factors. The determinations of U and Th concentrations of DL-1a (Canada Centre for Mineral and Energy Technology, CANMET) are based on sensitivity factors of CANMET DH-1, BL-1, BL-2, BL-3, and BL-4 standard material. The agreement between our U and Th values and those concentration values supplied from CANMET at the end of the round robin program for the standardization was found to be good. The application of spark source mass spectrometry is demonstrated by determining the concentrations of 10 geochemical relevant elements in two drill cores of a uranium deposit and neighbouring rocks. (orig.) [de

  6. Mass spectrometric measurements of trace gases, ions, and condensed sulfuric acid in jet aircraft exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, F.; Klemm, M.; Wohlfrom, K.H.; Stilp, T.; Reiner, T.; Schneider, J.; Curtius, J.; Grimm, F.; Sierau, B.; Frenzel, A.; Scheid, J.; Kirchner, G.; Hauler, T. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    1997-12-01

    We performed both ground based and aircraft based measurements of trace gases, ions, and condensed sulfuric acid in the wake of jet engines using quadrupole mass spectrometry in order to assess the impact of aircraft emissions on the atmosphere. Within this paper we report on the most striking results which we obtained since 1992 within the project `Schadstoffe in der Luftfahrt`. Ions produced by the combuster (chemiions, CI) have been detected for the first time at ground in the flame of a laboratory kerosene burner and at ground behind several jet engines. About 3 x 10{sup 15} negative CI have been emitted per kg fuel burnt by modern turbofan engines. The composition-analysis of negative CI revealed that they consist of clusters containing HNO{sub 3}, H{sub 2}SO{sub 4}, SO{sub 3}, and/or H{sub 2}O-molecules associated mainly to HSO{sub 4}{sup -} cores. At a plume age of 10 ms the precursor core ion NO{sub 3}{sup -} was only observed while the engines burnt fuel with a low sulfur content. Basing on a certain reaction scheme in the evolution of CI we calculated S(VI)(=SO{sub 3}+H{sub 2}SO{sub 4})-abundances and thereby an efficieny {epsilon} of fuel sulfur conversion to S(VI) of {epsilon}{approx}1%. The composition of ions measured under atmospheric conditions at 11 km altitude behind an Airbus A 310 at a distance of about 600 m (plume age: 3 sec) did not differ significantly from the composition of ions in the ambient atmosphere within the mass range of 1100 amu. Recently we detected SA in the condensed phase by evaporating the volatile components of aerosol particles and detection of H{sub 2}SO{sub 4} using IMRMS (ion molecule reaction mass spectrometry) within the plume of a testing aircraft burning fuels with different sulfur contents at cruise altitude. The efficiency {epsilon} of fuel sulfur conversion into S(VI) was estimated to be at least 0.3%. IMRMS-measurements of several trace gases have been performed in the individual plumes of various airliners

  7. Certification of Trace Elements and Methylmercury Mass Fractions in Tuna Fish Flesh Homogenate IAEA-436A

    International Nuclear Information System (INIS)

    2017-01-01

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioactive isotope analytical techniques to understand, monitor and protect the marine environment. The major impact of large coastal cities on marine ecosystems is a primary concern for the IAEA. The Marine Environment Studies Laboratory, as a part of IAEA Environment Laboratories in Monaco, acts as the analytical support centre for Member State laboratories and is the pillar of the quality assurance programme for the determination of non-nuclear pollutants, trace elements and organic contaminants in the marine environment. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. Good laboratory practice and quality assurance and control are essential components of the analytical process for the production of data. Quality control procedures are commonly based on analyses of certified reference materials to assess reproducibility and measurement biases and uncertainties. Certified reference materials are key tools for quality assurance. They are used to validate analytical methods and to establish traceability to internationally agreed references. They are cornerstones for laboratory accreditation and the correct implementation of national and international regulations. In the development and validation of new methods, certified reference materials play a vital role in state of the art technologies where measurements are critical. The IAEA supports the development and production of environmental certified reference materials for monitoring laboratories in Member States. The reference material IAEA-436, characterized for trace elements and methylmercury mass fractions in tuna fish flesh homogenate, was produced by the IAEA in Monaco in 2006. This publication describes the production of certified reference material IAEA-436A, which is based on the

  8. Mass-produced lonophore-based fluorescent microspheres for trace level determination of lead ions.

    Science.gov (United States)

    Telting-Diaz, Martin; Bakker, Eric

    2002-10-15

    The development and characterization of small, uniform, and mass-produced plasticized PVC-based sensing microspheres in view of rapid trace level analysis of lead ions is reported. Micrometer-sized particles obtained via an automated casting process were rendered selective for lead ions by doping them with highly selective components in a manner analogous to traditional optode sensing films. Single particles that contained the lipophilic ionophore N,N,N',N'-tetradodecyl-3-6-dioxaoctane-1-thio-8-oxodiamide (ETH 5493), the chromoionophore ETH 5418 together with a lipophilized indocarbocyanine derivative as internal reference dye (DiIC18), and lipophilic ion-exchanger sites sodium tetrakis[3,5-bistrifluoromethylphenyl]borate, yielded measurable lead responses at the low nanomolar level in pH buffered solutions. The detection limit for single particles was 3 x 10(-9) M at pH 5.7. The microspheres were fabricated via a reproducible formation of polymer droplets within a flowing aqueous phase followed by collection of spherical particles of approximately 13 microm in size. The particles were immobilized and assayed individually in a microflow cell via fluorescence microscopy. Selectivity patterns found were in agreement with those reported earlier for the lead-selective ligand ETH 5493, and all response functions were fully described by theory. In contrast to optode films that necessitated very long equilibration times and large sample volumes in diluted samples of analyte, particles exhibited extremely enhanced equilibrium response times. Thus, for lead sample concentrations at and above 5 x 10(-8) M, response times were approximately 3 min, whereas at the detection limit, complete equilibrium was recorded after just 15 min, with required sample volumes on the order of 1 mL This new class of microspheres appears to be suitable for rapid and sensitive ion detection at trace levels in environmental and biological applications.

  9. Determination of Trace Iron in Red Wine by Isotope Dilution Mass Spectrometry Using Multiple-Collector Inductively Coupled Plasma Mass Spectrometry

    International Nuclear Information System (INIS)

    Zhou Tao; Wang Jun; Lu Hai; Zhou Yuanjing; Li Haifeng

    2009-01-01

    This paper introduces determination of trace iron in red wine certified reference material by isotope dilution mass spectrometry (IDMS) method using a multiplecollector inductively coupled plasma mass spectrometry, equipped with a hexapole collision cell. The measurement procedure of iron isotopic abundance ratios was deeply researched. Reduced polyatomic ion interferences to iron isotopes ion by collision reaction using Ar and H 2 gas, high precise isotopic abundance ratios were achieved. Two relative measurement methods (ICP-MS and ICP-OES) were used to analyze trace iron in red wine. The results are compared with IDMS results, which indicate that they are accordant. The uncertainty analyses include each uncertainty factor in whole experiment and the uncertainty of used certified reference material and it shows that the procedure blank is not neglectable to detect limit and precision of the method. The establishment of IDMS method for analysis of trace iron in red wine supports the certification of certified reference materials. (authors)

  10. Detection of trace ink compounds in erased handwritings using electrospray-assisted laser desorption ionization mass spectrometry.

    Science.gov (United States)

    Kao, Yi-Ying; Cheng, Sy-Chyi; Cheng, Chu-Nian; Shiea, Jentaie; Ho, Hsiu-O

    2014-06-01

    Writings made with erasable pens on paper surfaces can either be rubbed off with an eraser or rendered invisible by changing the temperature of the ink. However, trace ink compounds still remain in the paper fibers even after rubbing or rendering. The detection of these ink compounds from erased handwritings will be helpful in knowing the written history of the paper. In this study, electrospray-assisted laser desorption ionization/mass spectrometry was used to characterize trace ink compounds remaining in visible and invisible ink lines. The ink compounds were desorbed from the paper surface by irradiating the handwritings with a pulsed laser beam; the desorbed analytes were subsequently ionized in an electrospray plume and detected by a quadrupole time-of-flight mass spectrometry mass analyzer. Because of the high spatial resolution of the laser beam, electrospray-assisted laser desorption ionization/mass spectrometry analysis resulted in minimal damage to the sample documents. Copyright © 2014 John Wiley & Sons, Ltd.

  11. Certification of Trace Element Mass Fractions in IAEA-457 Marine Sediment Sample

    International Nuclear Information System (INIS)

    2013-01-01

    The primary goal of the IAEA Environment Laboratories in Monaco (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA and its Environment Laboratories. Given that marine pollution assessments of such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments, the NAEL has assisted national laboratories and regional laboratory networks through its Reference Products for Environment and Trade programme since the early 1970s. Quality assurance (QA), quality control (QC) and associated good laboratory practice are essential components of all marine environmental monitoring studies. QC procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess reliability and comparability of measurement data. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparisons, which compare and evaluate analytical performance and measurement capabilities of participating laboratories. Data that are not based on adequate QA/QC can be erroneous and their misuse can lead to incorrect environmental management decisions. A marine sediment sample with certified mass fractions for Ag, Al, As, Cd, Cr, Co, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sn, Sr, V and Zn was recently produced by the NAEL in the frame of a project between the IAEA and the Korea Institute of Ocean Science and Technology. This report describes the sample preparation methodology, the material homogeneity and stability study, the selection of laboratories, the evaluation of results from the certification campaign and the assignment of property values and their associated uncertainty. As a result, reference values for mass fractions and associated expanded

  12. Trace level detection of explosives in solution using leidenfrost phenomenon assisted thermal desorption ambient mass spectrometry.

    Science.gov (United States)

    Saha, Subhrakanti; Mandal, Mridul Kanti; Chen, Lee Chuin; Ninomiya, Satoshi; Shida, Yasuo; Hiraoka, Kenzo

    2013-01-01

    The present paper demonstrates the detection of explosives in solution using thermal desorption technique at a temperature higher than Leidenfrost temperature of the solvent in combination with low temperature plasma (LTP) ionization. Leidenfrost temperature of a solvent is the temperature above which the solvent droplet starts levitation instead of splashing when placed on a hot metallic surface. During this desorption process, slow and gentle solvent evaporation takes place, which leads to the pre-concentration of less-volatile explosive molecules in the droplet and the explosive molecules are released at the last moment of droplet evaporation. The limits of detection for explosives studied by using this thermal desorption LTP ionization method varied in a range of 1 to 10 parts per billion (ppb) using a droplet volume of 20 μL (absolute sample amount 90-630 fmol). As LTP ionization method was applied and ion-molecule reactions took place in ambient atmosphere, various ion-molecule adduct species like [M+NO2](-), [M+NO3](-), [M+HCO3](-), [M+HCO4](-) were generated together with [M-H](-) peak. Each peak was unambiguously identified using 'Exactive Orbitrap' mass spectrometer in negative ionization mode within 3 ppm deviation compared to its exact mass. This newly developed technique was successfully applied to detect four explosives contained in the pond water and soil sample with minor sample pre-treatment and the explosives were detected with ppb levels. The present method is simple, rapid and can detect trace levels of explosives with high specificity from solutions.

  13. Development of a mass spectrometry immunoassay for unambiguous detection of egg allergen traces in wines.

    Science.gov (United States)

    Pilolli, Rosa; Chaudhari, Ravindra; Palmisano, Francesco; Monaci, Linda

    2017-02-01

    A mass spectrometry immunoassay (MSIA) specifically designed for the detection of egg allergens in wines is described. MSIA is based on an immunoaffinity enrichment procedure combined with targeted MS/MS detection of selected egg peptide markers. Polyclonal antibodies raised against native ovalbumin, chosen as the target protein tracing for egg powder, were immobilized onto low backpressure monolithic MSIA customized disposable tips. Ovalbumin-free wine samples were fortified with standard protein at different concentrations in the low microgram-per-milliliter range. A simple protocol was devised consisting of a 1:4 dilution of the wine sample with a basic solution for pH adjustment, followed by a semi-automated purification/enrichment step on MSIA customized disposable tips fitted on a multichannel electronic pipette. Among the main figures of merit, LOD and LOQ values as low as 0.01 and 0.03 μg/mL, respectively, and within-day precision of 18% should be noticed. Noteworthy, the developed assay outperformed current MS-based methods for the detection of allergenic protein in wine matrices, thanks to the immunoaffinity enrichment. In addition, compared to other immunoassays, the present approach boasts the unquestionable advantage of providing an unambiguous identification of the target protein by simultaneous detection of three unique peptide markers each giving three specific MS/MS transitions.

  14. Certification of Trace Element Mass Fractions in IAEA-458 Marine Sediment Sample

    International Nuclear Information System (INIS)

    2013-01-01

    The primary goal of the IAEA Environment Laboratories (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA and its Environment Laboratories. Given that marine pollution assessments of such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments, the NAEL has assisted national laboratories and regional laboratory networks through its Reference Products for Environment and Trade programme since the early 1970s. Quality assurance (QA), quality control (QC) and associated good laboratory practice are essential components of all marine environmental monitoring studies. QC procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess reliability and comparability of measurement data. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparisons, which compare and evaluate the analytical performance and measurement capabilities of participating laboratories. Data that are not based on adequate QA/QC can be erroneous, and their misuse can lead to incorrect environmental management decisions. This report describes the sample preparation methodology, material homogeneity and stability study, selection of laboratories, evaluation of results from the certification campaign and assignment of property values and their associated uncertainty. As a result, reference values for mass fractions and associated expanded uncertainty for 16 trace elements (Al, As, Cd, Cr, Co, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sr, Sn, V and Zn) in marine sediment were established

  15. Quantitative Detection of Trace Malachite Green in Aquiculture Water Samples by Extractive Electrospray Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Xiaowei Fang

    2016-08-01

    Full Text Available Exposure to malachite green (MG may pose great health risks to humans; thus, it is of prime importance to develop fast and robust methods to quantitatively screen the presence of malachite green in water. Herein the application of extractive electrospray ionization mass spectrometry (EESI-MS has been extended to the trace detection of MG within lake water and aquiculture water, due to the intensive use of MG as a biocide in fisheries. This method has the advantage of obviating offline liquid-liquid extraction or tedious matrix separation prior to the measurement of malachite green in native aqueous medium. The experimental results indicate that the extrapolated detection limit for MG was ~3.8 μg·L−1 (S/N = 3 in lake water samples and ~0.5 μg·L−1 in ultrapure water under optimized experimental conditions. The signal intensity of MG showed good linearity over the concentration range of 10–1000 μg·L−1. Measurement of practical water samples fortified with MG at 0.01, 0.1 and 1.0 mg·L−1 gave a good validation of the established calibration curve. The average recoveries and relative standard deviation (RSD of malachite green in lake water and Carassius carassius fish farm effluent water were 115% (6.64% RSD, 85.4% (9.17% RSD and 96.0% (7.44% RSD, respectively. Overall, the established EESI-MS/MS method has been demonstrated suitable for sensitive and rapid (<2 min per sample quantitative detection of malachite green in various aqueous media, indicating its potential for online real-time monitoring of real life samples.

  16. Analysis of Trace Elements in Rat Bronchoalveolar Lavage Fluid by Inductively Coupled Plasma Mass Spectrometry.

    Science.gov (United States)

    Qamar, Wajhul; Al-Ghadeer, Abdul Rahman; Ali, Raisuddin; Abuelizz, Hatem A

    2017-08-01

    The main objective was to determine the elemental profile of the lung lining fluid of rats which are used as model animals in various experiments. Lung lining fluid elemental constitution obtained after bronchoalveolar lavage fluid (BALF) was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to determine the biological trace elements along with calcium and magnesium. BALF was collected from healthy rats using a tracheal cannula. However, cells in BALF were counted to monitor any underlying inflammatory lung condition. Cell free BALF samples were processed and analyzed for the elements including magnesium (Mg), calcium (Ca), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), selenium (Se), bromine (Br), and iodine (I). In view of this, calcium concentration was the highest (6318.08 ± 3094.3 μg/L) and copper concentration was the lowest (0.89 ± 0.21 μg/L). The detected elements, from high to low concentration, include Ca > Mg > Fe > Br > I > Cr > Ni > Zn > Mn > Se > Cu. Pearson's correlation analysis revealed no significant correlation between cell count and concentration of any of the element detected in BALF. Correlation analysis also revealed significant positive correlation among Fe, I, Cr, Ni, and Mn. Ca was found to be correlated negatively with Cu and positively with Se. Br and Mg found to be positively correlated with each other. Zn remained the only element that was not found to be correlated with any of the elements in the rat BALF.

  17. Trace analysis in complex mixtures using a high-component filtering strategy with liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Zhang, Hui; Wang, Shao-Qing; Liu, Ying; Luo, Li-Ping; Liu, Peng; Qi, Lian-Wen; Li, Ping

    2012-11-01

    Trace constituents are widely present in complex mixtures, and trace analysis is challenging because of the unpredictable matrix. In this work, a high-component filtering strategy was developed for improved analysis of trace constituents in complex sample by liquid chromatography-mass spectrometry (LC-MS). Using a specifically designed chromatographic apparatus, the high-abundant fractions were filtered prior to LC-MS analysis. The samples complexity was reduced and the sample-loading amount for the rest low-level fractions can be considerably increased. The application of this approach was illustrated with an analytically challenging sample, a traditional Chinese herbal medicine named Compound Danshen Sample. We observed that the loss rate for 12 analytes during the filtering procedure ranged from 6.54 to 26.11%, but showed a stable repeatability with RSDanalysis, allowing six low compounds that cannot be quantified by the traditional methods to be tested by the filtering method. It can be predicted that the qualitative and quantitative trace analysis will be greatly improved when the loading samples is increased resulting from the filtration of high-level targets. The proposed strategy is promising to monitor trace constituents in diverse complex mixtures in the analytical field of pharmaceutics, metabonomics and environments. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Development of high resolution resonance ionization mass spectrometry for trace analysis of {sup 93m}Nb

    Energy Technology Data Exchange (ETDEWEB)

    Takatsuka, Takaaki; Tomita, Hideki, E-mail: tomita@nagoya-u.jp [Nagoya University (Japan); Sonoda, Tetsu [RIKEN Nishina Center (Japan); Sonnenschein, Volker [Johannes Gutenberg University (Germany); Sakamoto, Chika [Nagoya University (Japan); Mita, Hiroki [University of Tsukuba, Institute of Physics (Japan); Noto, Takuma [Nagoya University (Japan); Ito, Chikara; Maeda, Shigetaka [Japan Atomic Energy Agency, Oarai Research and Development Center (Japan); Iguchi, Tetsuo [Nagoya University (Japan); Wada, Michiharu [RIKEN Nishina Center (Japan); Wendt, Klaus [Johannes Gutenberg University (Germany); Moore, Iain [University of Jyvaeskylae, Department of Physics (Finland)

    2013-04-15

    {sup 93}Nb(n, n Prime ){sup 93m}Nb reaction allows retrospective estimation of integrated fast neutron dose in nuclear reactor. We proposed isomer-selective trace analysis of {sup 93m}Nb by Resonance Ionization Mass Spectrometry (RIMS) combined with a gas-jet atomic source and an injection locked Ti:Sapphire laser system operated at several kHz. Resonant ionization spectroscopy of Nb in gas-jet using Ti:Sapphire laser was demonstrated.

  19. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-461 Clam (Gafrarium tumidum) Sample

    International Nuclear Information System (INIS)

    2016-01-01

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact exerted by large coastal cities on marine ecosystems is an issue of primary concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. The IAEA Environment Laboratories has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance, quality control and associated good laboratory practice are essential components of all marine environmental monitoring studies. Quality control procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess the reliability and comparability of measurement data. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. This publication describes the production of the IAEA-461 certified reference material, which was produced following ISO Guide 34:2009, General Requirements for the Competence of Reference Material Producers. A sample of approximately 60 kg of clams (Gafrarium tumidum) was collected in Noumea, New Caledonia, and processed at the IAEA Environment Laboratories to produce a certified reference material of marine biota. The sample contained certified mass fractions for arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, mercury, methyl mercury, manganese, nickel, selenium, vanadium and zinc. The produced vials

  20. Advancement and application of gas chromatography isotope ratio mass spectrometry techniques for atmospheric trace gas analysis

    Science.gov (United States)

    Giebel, Brian M.

    2011-12-01

    The use of gas chromatography isotope ratio mass spectrometry (GC-IRMS) for compound specific stable isotope analysis is an underutilized technique because of the complexity of the instrumentation and high analytical costs. However stable isotopic data, when coupled with concentration measurements, can provide additional information on a compounds production, transformation, loss, and cycling within the biosphere and atmosphere. A GC-IRMS system was developed to accurately and precisely measure delta13C values for numerous oxygenated volatile organic compounds having natural and anthropogenic sources. The OVOCs include methanol, ethanol, acetone, methyl ethyl ketone, 2-pentanone, and 3-pentanone. Guided by the requirements for analysis of trace components in air, the GC-IRMS system was developed with the goals of increasing sensitivity, reducing dead-volume and peak band broadening, optimizing combustion and water removal, and decreasing the split ratio to the IRMS. The technique relied on a two-stage preconcentration system, a low-volume capillary reactor and water trap, and a balanced reference gas delivery system. Measurements were performed on samples collected from two distinct sources (i.e. biogenic and vehicle emissions) and ambient air collected from downtown Miami and Everglades National Park. However, the instrumentation and the method have the capability to analyze a variety of source and ambient samples. The measured isotopic signatures that were obtained from source and ambient samples provide a new isotopic constraint for atmospheric chemists and can serve as a new way to evaluate their models and budgets for many OVOCs. In almost all cases, OVOCs emitted from fuel combustion were enriched in 13C when compared to the natural emissions of plants. This was particularly true for ethanol gas emitted in vehicle exhaust, which was observed to have a uniquely enriched isotopic signature that was attributed to ethanol's corn origin and use as an alternative

  1. Time resolved investigations on biogenic trace gases exchanges using proton-transfer-reaction mass spectrometry

    International Nuclear Information System (INIS)

    Karl, T.

    2000-02-01

    1999/2000 completed this thesis and were used to evaluate and confirm the previously described investigations. The outcome of these measurements are summarized in the following abstracts submitted to the EGS 2000 (Nizza, France) and SASP 2000 (Folgaria, Italy) conferences: 1. Volatile organic compounds (VOCs) in the free troposphere at the Sonnblick Observatory, Austria (3106 m a.s.l.) were measured during November 1999. VOCs in the 0.5 to 5 ppbv range included hexenals, hexanal, methylbutanals, and especially 1-penten-3-ol; even higher levels of acetaldehyde (5 to 26 ppbv) were measured. The common origins of these compounds are proposed to be leaves which are senescing and/or subjected to freeze-thaw damage; this is inferred from laboratory investigations and by tracing air mass trajectories to urban or rural sites. This work suggests the Earth's deciduous forests may release large amounts of reactive VOCs during the autumn. 2. A PTR-MS-GC system was set up to identify lipoxygenase peroxidation products during freezing induced wounding, senescing and general wounding in various plants. In all laboratory experiments we observed substantial production of 1-penten-3-ol, cis-2-penten-1-ol, hexenal and hexenol isomers, all reactive oxygenates that contribute to tropospheric chemistry. Special attention is drawn to the production of pentenols, compounds which have not been reported to be present in large amounts in the atmosphere. PTR-MS online measurements on the Sonnblick observatory in the Austrian Alps (3106 m) show that even in the free troposphere substantial amounts of pentenols can be present as the result of ongoing freezing and senescing in deciduous plants. We also observed high mixing ratios of hexenals, acetaldehyde, methanol, 2-methylbutanal, 3-methylbutanal, EVK and acetone, all coming from local vegetation near the Sonnblick. 3. It was possible to estimate OH-radical concentrations on the 27 th November 1999 at the Sonnblick Observatory. During daytime the

  2. Quantitative sampling and analysis of trace elements in atmospheric aerosols: impactor characterization and Synchrotron-XRF mass calibration

    Directory of Open Access Journals (Sweden)

    A. Richard

    2010-10-01

    Full Text Available Identification of trace elements in ambient air can add substantial information to pollution source apportionment studies, although they do not contribute significantly to emissions in terms of mass. A method for quantitative size and time-resolved trace element evaluation in ambient aerosols with a rotating drum impactor and synchrotron radiation based X-ray fluorescence is presented. The impactor collection efficiency curves and size segregation characteristics were investigated in an experiment with oil and salt particles. Cutoff diameters were determined through the ratio of size distributions measured with two particle sizers. Furthermore, an external calibration technique to empirically link fluorescence intensities to ambient concentrations was developed. Solutions of elemental standards were applied with an ink-jet printer on thin films and area concentrations were subsequently evaluated with external wet chemical methods. These customized and reusable reference standards enable quantification of different data sets analyzed under varying experimental conditions.

  3. The measurement of trace emissions and combustion characteristics for a mass fire [Chapter 32

    Science.gov (United States)

    Ronald A. Susott; Darold E. Ward; Ronald E. Babbitt; Don J. Latham

    1991-01-01

    Concerns increase about the effects of emissions from biomass burning on global climate. While the burning of biomass constitutes a large fraction of world emissions, there are insufficient data on the combustion efficiency, emission factors, and trace gases produced in these fires, and on how these factors depend on the highly variable chemistry and burning condition...

  4. Feasibility of the detection of trace elements in particulate matter using online High-Resolution Aerosol Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Salcedo, D.; Laskin, Alexander; Shutthanandan, V.; Jimenez, Jose L.

    2012-08-10

    The feasibility of using an online thermal-desorption electron-ionization high-resolution aerosol mass spectrometer (AMS) for the detection of particulate trace elements was investigated analyzing data from Mexico City obtained during the MILAGRO 2006 field campaign, where relatively high concentrations of trace elements have been reported. This potential application is of interest due to the real-time data provided by the AMS, its high sensitivity and time resolution, and the widespread availability and use of this instrument. High resolution mass spectral analysis, isotopic ratios, and ratios of different ions containing the same elements are used to constrain the chemical identity of the measured ions. The detection of Cu, Zn, As, Se, Sn, and Sb is reported. There was no convincing evidence for the detection of other trace elements commonly reported in PM. The elements detected tend to be those with lower melting and boiling points, as expected given the use of a vaporizer at 600oC in this instrument. Operation of the AMS vaporizer at higher temperatures is likely to improve trace element detection. The detection limit is estimated at approximately 0.3 ng m-3 for 5-min of data averaging. Concentration time series obtained from the AMS data were compared to concentration records determined from offline analysis of particle samples from the same times and locations by ICP (PM2.5) and PIXE (PM1.1 and PM0.3). The degree of correlation and agreement between the three instruments (AMS, ICP, and PIXE) varied depending on the element. The AMS shows promise for real-time detection of some trace elements, although additional work including laboratory calibrations with different chemical forms of these elements are needed to further develop this technique and to understand the differences with the ambient data from the other techniques. The trace elements peaked in the morning as expected for primary sources, and the many detected plumes suggest the presence of multiple

  5. Real-time monitoring of trace-level VOCs by an ultrasensitive compact lamp-based VUV photoionization mass spectrometer

    Science.gov (United States)

    Sun, W. Q.; Shu, J. N.; Zhang, P.; Li, Z.; Li, N. N.; Liang, M.; Yang, B.

    2015-06-01

    In this study, we report on the development of a compact lamp-based vacuum ultraviolet (VUV) photoionization mass spectrometer (PIMS; hereafter referred to as VUV-PIMS) in our laboratory; it is composed of a radio frequency-powered VUV lamp, a VUV photoionizer, an ion-immigration region, and a reflection time-of-flight mass spectrometer. By utilizing the novel photoionizer consisting of a photoionization cavity and a VUV light baffle, extremely low background noise was obtained. An ultrasensitive detection limit (2σ) of 3 pptv was achieved for benzene after an acquisition time of 10 s. To examine its potential for application in real-time sample monitoring, the developed VUV-PIMS was employed for the continuous measurement of urban air for six days in Beijing, China. Strong signals of trace-level volatile organic compounds such as benzene and its alkylated derivatives were observed in the mass spectra. These initial experimental results reveal that the instrument can be used for the online monitoring of trace-level species in the atmosphere.

  6. Selected ion flow tube mass spectrometry (sift-MS) for on-line trace gas analysis

    Czech Academy of Sciences Publication Activity Database

    Smith, D.; Španěl, Patrik

    2005-01-01

    Roč. 24, č. 5 (2005), s. 661-700 ISSN 0277-7037 R&D Projects: GA ČR(CZ) GA202/03/0827; GA ČR(CZ) GA203/02/0737 Institutional research plan: CEZ:AV0Z40400503 Keywords : SIFT-MS * chemical ionization * trace gas analysis * breath analysis * urine headspace analysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 13.273, year: 2005

  7. Direct trace analysis of metals and alloys in a quadrupole ion-trap mass spectrometer

    CERN Document Server

    Song, K S; Yang, M; Cha, H K; Lee, J M; Lee, G H

    1999-01-01

    An ion-trap mass spectrometer adopting a quadrupole ion-trap and laser ablation/ionization method was constructed. The developed system was tested for composition analysis of some metals (Cu, stainless), and alloys (hastalloy C, mumetal) by mass spectrometry. Samples were analyzed by using laser ablation from a sample probe tip followed by a mass analysis with the quadrupole ion-trap. The quadrupole ion-trap was modified to enable laser ablation by a XeCl excimer laser pulse that passed radially through the ring electrode. A mass scan of the produced ions was performed in the mass selective instability mode wherein trapped ions were successively detected by increasing the rf voltage through the ring electrode. Factors affecting the mass resolution, such as pressure of buffer gas and ablation laser power, are discussed.

  8. Multi-elemental determination of trace elements in deep seawater by inductively coupled plasma mass spectrometry with resin preconcentration

    International Nuclear Information System (INIS)

    Sumida, Takashi; Nakazato, Tetsuya; Tao, Hiroaki

    2003-01-01

    A miniaturized column (ca. 3 mm i.d., 40 mm length), packed with a chelating resin (0.2 g) with iminodiacetic acid groups (Muromac A-1), was tested for the preconcentration of trace elements in seawater. After preconcentration, the column was washed with ammonium acetate buffer (pH 5.5) and water to remove the major elements, such as Ca and Mg, and was then eluted with 4 ml of 2 mol l -1 nitric acid. Twenty-six trace elements were determined by inductively coupled plasma mass spectrometry and inductively coupled plasma emission spectrometry. The necessary volume of the seawater sample was only 200 ml. The recoveries for most of the elements tested were over 90%, although those for Al, V and Th were around 70%. The trueness and precision were evaluated by analyzing a standard reference material of seawater (NASS-4, NRC Canada). The observed values obtained with the present method showed good agreement with the certified values. The present method was also applied to deep seawater samples collected at Muroto, Japan. A difference in the rare earth element pattern, especially the Ce anomaly, between the deep seawater sample and the surface seawater sample was observed, as well as the differences of the concentrations of many trace elements. (author)

  9. Use of INAA and ICP-MS for the assessment of trace element mass fractions in adult and geriatric prostate

    International Nuclear Information System (INIS)

    Vladimir Zaichick; Sofia Zaichick; Northwestern University, Chicago, IL

    2014-01-01

    The variation with age of the mass fraction of 54 trace elements (Ag, Al, As, Au, B, Be, Bi, Br, Cd, Ce, Co, Cr, Cs, Dy, Er, Eu, Fe, Ga, Gd, Hf, Hg, Ho, Ir, La, Li, Lu, Mn, Mo, Nb, Nd, Ni, Pb, Pd, Pr, Pt, Rb, Re, Sb, Sc, Se, Sm, Sn, Ta, Tb, Te, Th, Ti, Tl, Tm, U, Y, Yb, Zn, and Zr) in intact nonhyperplastic prostate of 65 healthy 21-87 year old males was investigated by instrumental neutron activation analysis with high resolution spectrometry of long-lived radionuclides and inductively coupled plasma mass spectrometry. This work revealed that there is a significant tendency for an increase in Bi, Cd, Co, Fe, Hg, Sc, Sn, Th, U, and Zn (p < 0.0014) mass fraction in normal prostate from age 21 years to the sixth decade. In the sixth to ninth decades the mass fractions of almost all chemical elements investigated in nonhyperplastic prostates were maintained at approximately stable levels. Our finding of correlation between pairs of prostatic chemical element mass fractions indicates that there is a great disturbance of prostatic chemical element relationships with increasing age. (author)

  10. Certification for Trace Elements and Methyl Mercury Mass Fractions in IAEA-452 Scallop (Pecten maximus) Sample

    International Nuclear Information System (INIS)

    2013-01-01

    The primary goal of the IAEA Environment Laboratories (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA, particularly to its Environment Laboratories. The marine pollution assessments needed to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. Two fundamental requirements to ensure the reliability of analytical results are quality control (QC) and quality assurance (QA). Since the early 1970s, NAEL has been assisting national laboratories and regional laboratory networks through its reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Relevant activities include global interlaboratory comparison exercises and regional proficiency tests, the production of marine reference materials, and the development of reference methods for analysis of trace elements and organic pollutants in marine samples. QA, QC and associated good laboratory practice should be essential components of all marine environmental monitoring. QC procedures are commonly based on the analysis of reference materials to assess reproducibility and measurement bias. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparison exercises, which compare and evaluate the analytical performance and measurement capabilities of participating laboratories. The need for good QA/QC in the chemical analysis of marine environmental samples is widely recognized and has been tested in a number of international QA exercises. Such diligence also needs to be applied to other components of the monitoring exercise, since these may represent a greater source of error in many instances. Data that are not based on adequate QA/QC can be erroneous, and their misuse can lead

  11. Feeding the fire: tracing the mass-loading of 107 K galactic outflows with O VI absorption

    Science.gov (United States)

    Chisholm, J.; Bordoloi, R.; Rigby, J. R.; Bayliss, M.

    2018-02-01

    Galactic outflows regulate the amount of gas galaxies convert into stars. However, it is difficult to measure the mass outflows remove because they span a large range of temperatures and phases. Here, we study the rest-frame ultraviolet spectrum of a lensed galaxy at z ˜ 2.9 with prominent interstellar absorption lines from O I, tracing neutral gas, up to O VI, tracing transitional phase gas. The O VI profile mimics weak low-ionization profiles at low velocities, and strong saturated profiles at high velocities. These trends indicate that O VI gas is co-spatial with the low-ionization gas. Further, at velocities blueward of -200 km s-1 the column density of the low-ionization outflow rapidly drops while the O VI column density rises, suggesting that O VI is created as the low-ionization gas is destroyed. Photoionization models do not reproduce the observed O VI, but adequately match the low-ionization gas, indicating that the phases have different formation mechanisms. Photoionized outflows are more massive than O VI outflows for most of the observed velocities, although the O VI mass outflow rate exceeds the photoionized outflow at velocities above the galaxy's escape velocity. Therefore, most gas capable of escaping the galaxy is in a hot outflow phase. We suggest that the O VI absorption is a temporary by-product of conduction transferring mass from the photoionized phase to an unobserved hot wind, and discuss how this mass-loading impacts the observed circum-galactic medium.

  12. Bioimaging mass spectrometry of trace elements – recent advance and applications of LA-ICP-MS: A review

    Energy Technology Data Exchange (ETDEWEB)

    Becker, J.Sabine, E-mail: s.becker@fz-juelich.de [Central Institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich, Jülich D-52425 (Germany); Matusch, Andreas, E-mail: a.matusch@fz-juelich.de [Institute for Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich D-52425 (Germany); Wu, Bei, E-mail: b.wu@fz-juelich.de [Central Institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich, Jülich D-52425 (Germany)

    2014-07-04

    Highlights: • Bioimaging LA-ICP-MS is established for trace metals within biomedical specimens. • Trace metal imaging allows to study brain function and neurodegenerative diseases. • Laser microdissection ICP-MS was applied to mouse brain hippocampus and wheat root. - Abstract: Bioimaging using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers the capability to quantify trace elements and isotopes within tissue sections with a spatial resolution ranging about 10–100 μm. Distribution analysis adds to clarifying basic questions of biomedical research and enables bioaccumulation and bioavailability studies for ecological and toxicological risk assessment in humans, animals and plants. Major application fields of mass spectrometry imaging (MSI) and metallomics have been in brain and cancer research, animal model validation, drug development and plant science. Here we give an overview of latest achievements in methods and applications. Recent improvements in ablation systems, operation and cell design enabled progressively better spatial resolutions down to 1 μm. Meanwhile, a body of research has accumulated covering basic principles of the element architecture in animals and plants that could consistently be reproduced by several laboratories such as the distribution of Fe, Cu, Zn in rodent brain. Several studies investigated the distribution and delivery of metallo-drugs in animals. Hyper-accumulating plants and pollution indicator organisms have been the key topics in environmental science. Increasingly, larger series of samples are analyzed, may it be in the frame of comparisons between intervention and control groups, of time kinetics or of three-dimensional atlas approaches.

  13. A new method for the determination of NO2 traces using isotope dilution and mass spectrometry analysis

    International Nuclear Information System (INIS)

    Stevens, C.; Barat, F.; Nguyen Nghi, H.

    1975-01-01

    A new method for the determination of NO 2 traces, in the order of 1ppb (10 -9 ), in atmosphere and stratosphere is described. The method consists in an isotope dilution technique using 15 NO 2 , followed by the reduction of NO 2 to N 2 and a mass spectrometry analysis. A known amount of 15 NO 2 is added to the air samples. Then, NO 2 is separated from H 2 O, HNO 3 , CO 2 and N 2 O and transferred to a SiO 2 reactor by trapping at -196 deg C. In the reactor NO 2 is reduced to N 2 by reaction with electrolytic Cu heated at 580 deg C. The mass 29/mass 30 ratio corresponding to 15 N 14 N and 15 N 15 N is determined by mass spectrometry. The sensitivity of the method depends on the contamination introduced during the analysis of the sample (reagents, separation and measuring devices). The contamination is reproducible and in the order of 4.5+-0.5 10 -2 mm 3 N 2 [fr

  14. Ocean Basalt Simulator version 1 (OBS1): Trace element mass balance in adiabatic melting of a pyroxenite-bearing peridotite

    Science.gov (United States)

    Kimura, Jun-Ichi; Kawabata, Hiroshi

    2015-01-01

    We present a new numerical trace element mass balance model for adiabatic melting of a pyroxenite-bearing peridotite for estimating mantle potential temperature, depth of melting column, and pyroxenite fraction in the source mantle for a primary ocean basalt/picrite. The Ocean Basalt Simulator version 1 (OBS1) uses a thermodynamic model of adiabatic melting of a pyroxenite-bearing peridotite with experimentally/thermodynamically parameterized liquidus-solidus intervals and source mineralogy. OBS1 can be used to calculate a sequence of adiabatic melting with two melting models, including (1) melting of peridotite and pyroxenite sources with simple mixing of their fractional melts (melt-melt mixing model), and (2) pyroxenite melting, melt metasomatism in the host peridotite, and melting of the metasomatized peridotite (source-metasomatism model). OBS1 can be used to explore (1) the fractions of peridotite and pyroxenite, (2) mantle potential temperature, (3) pressure of termination of melting, (4) degree of melting, and (5) residual mode of the sources. In order to constrain these parameters, the model calculates a mass balance for 26 incompatible trace elements in the sources and in the generated basalt/picrite. OBS1 is coded in an Excel spreadsheet and runs with VBA macros. Using OBS1, we examine the source compositions and conditions of the mid-oceanic ridge basalts, Loihi-Koolau basalts in the Hawaiian hot spot, and Jurassic Shatsky Rise and Mikabu oceanic plateau basalts and picrites. The OBS1 model shows the physical conditions, chemical mass balance, and amount of pyroxenite in the source peridotite, which are keys to global mantle recycling.

  15. Application of inductively coupled plasma mass spectrometry (ICP/MS) to detection of trace elements, heavy metals and radioisotopes in scalp hair

    International Nuclear Information System (INIS)

    Ozturk, Yildirim; Benderli, Cihan

    2010-01-01

    Trace element analysis of human hair has the potential to reveal retrospective information about an individual's nutritional status and exposure. As trace elements are incorporated into the hair during the growth process, longitudinal segments of the hair may reflect the body burden during the growth period. it was evaluated the potential of human hair to indicate exposure or nutritional status over time by analysing trace element profiles in single strands of human hair. By using inductively coupled plasma mass spectrometry (ICP-MS), it was achieved profiles of 43 elements in single strands of human hair. It was shown that trace element analysis along single strands of human hair can yield information about essential and toxic elements and for some elements, can be correlated with seasonal changes in diet and exposure. The information obtained from the trace element profiles of human hair in this study substantiates the potential of hair as a biomarker

  16. Characterization of extreme ultraviolet laser ablation mass spectrometry for actinide trace analysis and nanoscale isotopic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Green, Tyler; Kuznetsov, Ilya; Willingham, David; Naes, Benjamin E.; Eiden, Gregory C.; Zhu, Zihua; Chao, W.; Rocca, Jorge J.; Menoni, Carmen S.; Duffin, Andrew M.

    2017-01-01

    The purpose of this research was to characterize Extreme Ultraviolet Time-of-Flight (EUV TOF) Laser Ablation Mass Spectrometry for high spatial resolution elemental and isotopic analysis. We compare EUV TOF results with Secondary Ionization Mass Spectrometry (SIMS) to orient the EUV TOF method within the overall field of analytical mass spectrometry. Using the well-characterized NIST 61x glasses, we show that the EUV ionization approach produces relatively few molecular ion interferences in comparison to TOF SIMS. We demonstrate that the ratio of element ion to element oxide ion is adjustable with EUV laser pulse energy and that the EUV TOF instrument has a sample utilization efficiency of 0.014%. The EUV TOF system also achieves a lateral resolution of 80 nm and we demonstrate this lateral resolution with isotopic imaging of closely spaced particles or uranium isotopic standard materials.

  17. Large-scale correlations in gas traced by Mg II absorbers around low-mass galaxies

    Science.gov (United States)

    Kauffmann, Guinevere

    2018-03-01

    The physical origin of the large-scale conformity in the colours and specific star formation rates of isolated low-mass central galaxies and their neighbours on scales in excess of 1 Mpc is still under debate. One possible scenario is that gas is heated over large scales by feedback from active galactic nuclei (AGNs), leading to coherent modulation of cooling and star formation between well-separated galaxies. In this Letter, the metal line absorption catalogue of Zhu & Ménard is used to probe gas out to large projected radii around a sample of a million galaxies with stellar masses ˜1010M⊙ and photometric redshifts in the range 0.4 effective volume of 2.2 Gpc3. A statistically significant excess of Mg II absorbers is present around the red-low-mass galaxies compared to their blue counterparts out to projected radii of 10 Mpc. In addition, the equivalent width distribution function of Mg II absorbers around low-mass galaxies is shown to be strongly affected by the presence of a nearby (Rp < 2 Mpc) radio-loud AGNs out to projected radii of 5 Mpc.

  18. Tracing non-conservative mass transfer eras in close binaries from observed period variations

    Science.gov (United States)

    Nanouris, N.; Kalimeris, A.; Antonopoulou, E.; Rovithis-Livaniou, H.

    2013-09-01

    The pure information directly taken from the observed orbital evolution of eclipsing binary stars (centuries at most) is valuable for the study of many important physical mechanisms related to the stellar structure. Especially in the case of eclipsing binary systems, this may happen by monitoring their eclipse timing variations, i.e. by means of an O-C diagram analysis. As long as a binary system attains a semi-detached configuration, material begins to flow from the component that fills its Roche lobe toward its mate through the first Lagrangian (L1) point. Here, we examine two non conservative mass transfer (MT) paths. The MT process is then accompanied by mass and angular momentum loss from the system. In the first path, angular momentum is removed through a hot spot which re-emits part of the incoming material, and in the second, angular momentum is carried away via an outer Lagrangian point (L2/L3) due to the small accumulating efficiency of the accretion disk surrounding the gainer. Dealing with the less massive component as the donor in the latter path, it is shown that there is always a critical mass ratio over which the period is expected to decrease, contrary to what the fully conservative MT predicts. Consistent with our expectations, the critical values become progressively smaller as the degree of liberalism is gradually widened. The O-C diagram of several semi-detached systems, expecting to experience a liberal era, is individually examined aiming to estimate both the mass transfer and the mass loss rate.

  19. A microwave plasma torch quadrupole mass spectrometer for monitoring trace levels of lead and cadmium in water.

    Science.gov (United States)

    Zhu, Zhiqiang; Jiang, Tao; Xiong, Xiaohong; Zou, Wei

    2016-08-01

    The microwave plasma torch (MPT) is a low power-consumption and easily operated plasma generator. As an ambient ion source, the MPT can be coupled with various mass spectrometers and applied in real-time analysis of metal elements in water for the demands of environmental control and water quality inspection. We constructed a quadrupole mass spectrometer with an MPT as the ion source to detect directly trace levels of lead and cadmium in water. Without any pretreatments,water samples were first pneumatically nebulized with a desolvation unit, then flowed through the central tube of the MPT and finally entered the plasma. After that, the metal ions produced were introduced into the mass spectrometer to be analyzed via an atmospheric inlet of a stainless steel capillary tube. The MPT mass spectra of lead and cadmium ions were characterized with clear unit isotopic resolution. The sensitivity reached levels of 20 ng/L for lead and 72.7 ng/L for cadmium in water, respectively. The linear response range covered at least 2 orders of magnitude. Moreover, a single aqueous sample could be completely analyzed within 3 minutes, providing reasonably relative standard deviation values. Our results demonstrated that this MPT mass spectrometer is a useful tool for the monitoring of lead and cadmium ions in water, which makes it a potential alternative to ICP-MS, to be used in the fields of environmental control and water quality and foodstuff safety inspection. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Ultra-trace determination of neptunium-237 and plutonium isotopes in urine samples by compact accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dai, X.; Christl, M.; Kramer-Tremblay, S., E-mail: sheila.kramer-tremblay@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Synal, H-A. [ETH Zurich, Lab. of Ion Beam Physics, Zurich (Switzerland)

    2015-12-15

    Ultra-trace analysis of actinides, such as Pu isotopes and {sup 237}Np, in bioassay samples is often needed for radiation protection programs at nuclear facilities. Accelerator mass spectrometry (AMS), particularly the compact ETH Zurich system “Tandy”, has evolved over the years as one of the most sensitive, selective, and robust techniques for actinide analysis. Employment of the AMS technique can reduce the demands on sample preparation chemistry and increase sample analysis throughput, due to very low instrumental detection limit, high rejection of interferences, and low susceptibility to adverse sample matrices. Initial research and development tests were performed to explore and demonstrate the analytical capability of AMS for Pu and Np urine bioassay. In this study, urine samples spiked with femtogram levels of Np and Pu isotopes were prepared and measured using compact ETH AMS system and the results showed excellent analytical capability for measuring Np and Pu isotopes at femtogram/litre levels in urine. (author)

  1. Analytical study of a gas of gluonic quasiparticles at high temperature: Effective mass, pressure, and trace anomaly

    International Nuclear Information System (INIS)

    Giacosa, Francesco

    2011-01-01

    The thermodynamical properties of a pure Yang-Mills theory SU(N) is described by a gas of gluonic quasiparticles with temperature-dependent mass m(T) and a bag function B(T). The analytic behavior of m(T) and the pressure p in the temperature range 2.5-5T c are derived and constraints on the parameters defining B(T) are discussed. The trace anomaly θ=ρ-3p is evaluated in the high T domain: it is dominated by a quadratic behavior θ=nKT 2 , where n=2(N 2 -1) is the number of degrees of freedom and K is an integration constant which does not depend on the bag function B(T). The quadratic rise of θ is in good agreement with recent lattice simulations.

  2. Combined liquid chromatography-mass spectrometry for trace analysis of pharmaceuticals

    International Nuclear Information System (INIS)

    Schmidt, L.; Danigel, H.; Jungclas, H.

    1982-01-01

    A 252 Cf-plasma desorption mass spectrometer (PDMS) for the analysis of thin layers from nonvolatile organic samples has been set up to be combined with a liquid chromatograph. A novel interface performs the direct inlet of the liquid sample through a capillary into the vacuum system of the spectrometer. Samples of drugs are periodically collected, transferred to the ion source and analysed using a rotating disk. This on-line sample preparation has been tested for three antiarrhythmic drugs using various solvents and mixtures. (orig.)

  3. The study of trace metal absoption using stable isotopes and mass spectrometry

    Science.gov (United States)

    Fennessey, P. V.; Lloyd-Kindstrand, L.; Hambidge, K. M.

    1991-12-01

    The absorption and excretion of zinc stable isotopes have been followed in more than 120 human subjects. The isotope enrichment determinations were made using a standard VG 7070E HF mass spectrometer. A fast atom gun (FAB) was used to form the ions from a dry residue on a pure silver probe tip. Isotope ratio measurements were found to have a precision of better than 2% (relative standard deviation) and required a sample size of 1-5 [mu]g. The average true absorption of zinc was found to be 73 ± 12% (2[sigma]) when the metal was taken in a fasting state. This absorption figure was corrected for tracer that had been absorbed and secreted into the gastrointestinal (GI) tract over the time course of the study. The average time for a majority of the stable isotope tracer to pass through the GI tract was 4.7 ± 1.9 (2[sigma]) days.

  4. TRACING MOLECULAR GAS MASS IN EXTREME EXTRAGALACTIC ENVIRONMENTS: AN OBSERVATIONAL STUDY

    International Nuclear Information System (INIS)

    Zhu Ming; Papadopoulos, Padeli P.; Xilouris, Emmanuel M.; Kuno, Nario; Lisenfeld, Ute

    2009-01-01

    We present a new observational study of the 12 CO(1-0) line emission as an H 2 gas mass tracer under extreme conditions in extragalactic environments. Our approach is to study the full neutral interstellar medium (H 2 , H I, and dust) of two galaxies whose bulk interstellar medium (ISM) resides in environments that mark (and bracket) the excitation extremes of the ISM conditions found in infrared luminous galaxies, the starburst NGC 3310, and the quiescent spiral NGC 157. Our study maintains a robust statistical notion of the so-called X = N(H 2 )/I CO factor (i.e., a large ensemble of clouds is involved) while exploring its dependence on the very different average ISM conditions prevailing within these two systems. These are constrained by fully sampled 12 CO(3-2) and 12 CO(1-0) observations, at a matched beam resolution of half-power beam width ∼15'', obtained with the James Clerk Maxwell Telescope (JCMT) on Mauna Kea (Hawaii) and the 45 m telescope of the Nobeyama Radio Observatory in Japan, combined with sensitive 850 μm and 450 μm dust emission and H I interferometric images which allow a complete view of all the neutral ISM components. Complementary 12 CO(2-1) observations were obtained with the JCMT toward the center of the two galaxies. We found an X factor varying by a factor of 5 within the spiral galaxy NGC 157 and about two times lower than the Galactic value in NGC 3310. In addition, the dust emission spectrum in NGC 3310 shows a pronounced submillimeter 'excess'. We tried to fit this excess by a cold dust component but very low temperatures were required (T C ∼ 5-11 K) with a correspondingly low gas-to-dust mass ratio of ∼5-43. We furthermore show that it is not possible to maintain the large quantities of dust required at these low temperatures in this starburst galaxy. Instead, we conclude that the dust properties need to be different from Galactic dust in order to fit the submillimeter 'excess'. We show that the dust spectral energy

  5. Analysis of trace Fe in sea water by using inductively coupled plasma mass spectrometry with solid phase chelate extraction technique

    International Nuclear Information System (INIS)

    Aimoto, Michihiro; Kato, Toshiaki; Kiso, Eiji; Tsutsumi, Naoto; Miki, Osamu

    2010-01-01

    Field experiments on recovering from barren sea ground called 'Isoyake' by providing Fe in sea water to restore seaweed beds on barren ground, has been carried out. Fe supply source, a mixture of steelmaking slag and compost (humic wood chips), were laid underground in shoreline. A certain amount of restoration of seaweed beds has been confirmed at the locations for several years. Quantitative determination of trace amount of Fe in sea water in necessary to validate the effect of iron source. However, to analyze dissolved Fe in sea water was difficult due to its trace concentration and the interference by high concentration of salts in the analytical samples. We established new analysis method of Fe in sea water, by treating sea water with solid phase chelate extraction and analyzed by inductively coupled plasma mass spectrometry with cool plasma condition. This method was successfully applied for the sea water sample taken from experimental site. Other water quality parameters in the experimental site were also investigated. Fe concentration was significantly highest around the Fe supply source and was decreased with the distance. Although the concentrations of dissolved silica, Mg and Ca were correlated to electrical conductivity of the sample water, Fe concentration was not. According to those results, the concentration of dissolved Fe from steelmaking slag was confirmed, and Fe might be contiguously supplied to the sea water from Fe supply source and promoted the growth of seaweeds. Therefore, applying a mixture of steelmaking slag and compost as Fe supply source is an effective technique to supply dissolved iron to Isoyake area. (author)

  6. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-470 Oyster Sample

    International Nuclear Information System (INIS)

    2016-01-01

    This publication describes the production of the IAEA-470 certified reference material, which was produced following ISO Guide 34:2009, General Requirements for the Competence of Reference Materials Producers. A sample of approximately 10 kg of dried oysters was taken from oysters collected, dissected and freeze-dried by the Korean Ocean Research and Development Institute, and was further processed at the IAEA Environment Laboratories to produce a certified reference material. The sample contained certified mass fractions for arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, mercury, methyl mercury, rubidium, selenium, silver, sodium, strontium, vanadium and zinc. The produced vials containing the processed oyster sample were carefully capped and stored for further certification studies. Between-unit homogeneity and stability during dispatch and storage were quantified in accordance with ISO Guide 35:2006, Reference Materials - General and Statistical Principles for Certification. The material was characterized by laboratories with demonstrated competence and adhering to ISO/IEC 17025:2005. Uncertainties of the certified values were calculated in compliance with the guide to the Expression of Uncerdainty in Measurement (JCGM 100:2008), including uncertainty associated with heterogeneity and instability of the material, and with the characterization itself. The material is intended for the quality control and assessment of method performance. As with any reference material, it can also be used for control charts or validation studies

  7. Trace metal analysis of road dust by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Powell, M.J.; Liu, L.; Gnanalingham, N.; Peters, L.

    2000-01-01

    Dust from roads in an air impingement zone close to anthropogenic sources of air pollutants can be a concern for people living in the immediate vicinity. The Ministry of the Environment (MOE) has conducted a case study to monitor the concentration of uranium, strontium, thorium and arsenic in road dust from one such area. A method for the analysis of road dust by inductively coupled plasma mass spectrometry (ICP-MS) has been developed with detection limits in the ng/1 range. A digestion technique has been developed by conducting experiments using single and combinations of acids in open-vessel wet digestions. Accuracy has been determined by the use of matrix representative certified reference materials (CRMs). Digestion precision was determined by elemental concentration measurements of the most representative CRM through replicates. Spike recovery data were from 95% to 110% for all elements, and inter-method comparison studies between hydride generation atomic absorption spectrometry (AAS) inductively coupled plasma atomic emission spectrometry (ICP-AES) and ICP-MS for arsenic and strontium show good agreement. (author)

  8. Detection of clenbuterol at trace levels in doping analysis using different gas chromatographic-mass spectrometric techniques.

    Science.gov (United States)

    Yang, Sheng; Liu, Xin; Xing, Yanyi; Zhang, Dapeng; Wang, Shan; Wang, Xiaobing; Xu, Youxuan; Wu, Moutian; He, Zhenwen; Zhao, Jian

    2013-01-01

    This study demonstrates the development of a gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS-MS) assay to detect clenbuterol in human urine and the comparison of this method with GC-MS techniques and gas chromatography-high resolution mass spectrometry (GC-HRMS) techniques. Urine samples were hydrolyzed with β-glucuronidase, extracted with methyl tert-butyl ether and dried under nitrogen. The derivative reagent was N-methyl-N-(trimethylsilyl)-trifluoroacetamide with NH4I and was analyzed by GC-MS, GC-MS-MS and GC-HRMS. A validation study was conducted by GC-MS-MS. The analyses of clenbuterol using different mass spectrometric techniques were compared. The limit of detection (LOD) for clenbuterol in human urine was 2 ng/mL by GC-MS (selected ion monitoring mode: SIM mode), 0.06 ng/mL by GC-HRMS and 0.03 ng/mL by GC-MS-MS, respectively, while the LOD by GC-HRMS was 0.06. With GC-MS-MS, the intra-assay and inter-assay precisions were less than 15%, the recoveries were 86 to 112% and the linear range was 0.06 to 8.0 ng/mL. The GC-MS under SIM mode can be used as a screening tool to detect clenbuterol at trace levels in human urine. The GC-MS-MS and GC-HRMS methods can confirm clenbuterol when its concentration is below 2 ng/mL. The results demonstrate that the GC-MS-MS method is quite sensitive, specific and reliable for the detection of clenbuterol in doping analysis.

  9. The potential of sedimentary foraminiferal rare earth element patterns to trace water masses in the past

    Science.gov (United States)

    Osborne, Anne H.; Hathorne, Ed C.; Schijf, Johan; Plancherel, Yves; Böning, Philipp; Frank, Martin

    2017-04-01

    Dissolved rare earth element (REE) concentration data from intermediate and deep seawater form an array characterized by higher middle-REE enrichments (MREE/MREE*) in the North Atlantic and a progressive increase in heavy-to-light REE ratios (HREE/LREE) as water masses age. The REEs in foraminifera are fractionated toward higher MREE/MREE* and lower HREE/LREE relative to seawater. Calculations based on a scavenging model show that the REE patterns in uncleaned core-top foraminifera resemble those adsorbed onto calcite, particulate organic material, and hydrous ferric oxides but the full extent of the REE fractionation measured in foraminifera was not reproduced by the model. However, differences in the HREE/LREE and MREE/MREE* ratios and the cerium anomaly between ocean basins are preserved and are in agreement with the seawater REE distribution. Under oxic conditions, the HREE/LREE and MREE/MREE* compositions of uncleaned foraminifera at the sediment/seawater boundary are preserved during burial but the cerium anomaly is sensitive to burial depth. In suboxic sedimentary environments, all uncleaned foraminiferal REE concentrations are elevated relative to core-top values indicating addition of REEs from pore waters. The HREE/LREE ratio is highest when sedimentation rates were greatest and when high Fe/Ca ratios in the uncleaned foraminifera indicate that Fe was mobile. In sediments that have not experienced suboxic conditions during burial, uncleaned foraminifera preserve the seawater signal taken up at the sediment/seawater interface and are therefore suggested to be a suitable archive of changes in the REE signal of past bottom waters.

  10. A general method for the calculation of absolute trace gas concentrations in air and breath from selected ion flow tube mass spectrometry data

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Dryahina, Kseniya; Smith, D.

    249-250, - (2006), s. 230-239 ISSN 1387-3806 R&D Projects: GA ČR GA202/03/0827 Institutional research plan: CEZ:AV0Z40400503 Keywords : selected ion flow tube * mass spectrometry * SIFT-MS * trace gas analysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.337, year: 2006

  11. Quantification of clenbuterol at trace level in human urine by ultra-high pressure liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Nicoli, Raul; Petrou, Michael; Badoud, Flavia; Dvorak, Jiri; Saugy, Martial; Baume, Norbert

    2013-05-31

    Clenbuterol is a β2 agonist agent with anabolic properties given by the increase in the muscular mass in parallel to the decrease of the body fat. For this reason, the use of clenbuterol is forbidden by the World Anti-Doping Agency (WADA) in the practice of sport. This compound is of particular interest for anti-doping authorities and WADA-accredited laboratories due to the recent reporting of risk of unintentional doping following the eating of meat contaminated with traces of clenbuterol in some countries. In this work, the development and the validation of an ultra-high pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method for the quantification of clenbuterol in human urine is described. The analyte was extracted from urine samples by liquid-liquid extraction (LLE) in basic conditions using tert butyl-methyl ether (TBME) and analyzed by UHPLC-MS/MS with a linear gradient of acetonitrile in 9min only. The simple and rapid method presented here was validated in compliance with authority guidelines and showed a limit of quantification at 5pg/mL and a linearity range from 5pg/mL to 300pg/mL. Good trueness (85.8-105%), repeatability (5.7-10.6% RSD) and intermediate precision (5.9-14.9% RSD) results were obtained. The method was then applied to real samples from eighteen volunteers collecting urines after single oral doses administration (1, 5 and 10μg) of clenbuterol-enriched yogurts. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Quantification of Stable Isotope Traces Close to Natural Enrichment in Human Plasma Metabolites Using Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Lisa Krämer

    2018-02-01

    Full Text Available Currently, changes in metabolic fluxes following consumption of stable isotope-enriched foods are usually limited to the analysis of postprandial kinetics of glucose. Kinetic information on a larger diversity of metabolites is often lacking, mainly due to the marginal percentage of fully isotopically enriched plant material in the administered food product, and hence, an even weaker 13C enrichment in downstream plasma metabolites. Therefore, we developed an analytical workflow to determine weak 13C enrichments of diverse plasma metabolites with conventional gas chromatography-mass spectrometry (GC-MS. The limit of quantification was increased by optimizing (1 the metabolite extraction from plasma, (2 the GC-MS measurement, and (3 most importantly, the computational data processing. We applied our workflow to study the catabolic dynamics of 13C-enriched wheat bread in three human subjects. For that purpose, we collected time-resolved human plasma samples at 16 timepoints after the consumption of 13C-labeled bread and quantified 13C enrichment of 12 metabolites (glucose, lactate, alanine, glycine, serine, citrate, glutamate, glutamine, valine, isoleucine, tyrosine, and threonine. Based on isotopomer specific analysis, we were able to distinguish catabolic profiles of starch and protein hydrolysis. More generally, our study highlights that conventional GC-MS equipment is sufficient to detect isotope traces below 1% if an appropriate data processing is integrated.

  13. The coupling of capillary electrophoresis-inductively coupled plasma mass spectrometer as a speciation instrument for actinides at trace level

    International Nuclear Information System (INIS)

    Delorme, A.

    2004-01-01

    An interface between the separation technique (capillary electrophoresis) and the analytical technique (Inductively Coupled Plasma - Mass Spectrometer) was developed. In that sense, bibliographic and parametric studies allowed to define necessary conditions for the good working of both techniques. The results obtained led to the realisation of an interface capillary electrophoresis / ICP-MS (CE / ICP-MS). This one was experimentally validated on classical separations (alkalis / earth-alkalis and lanthanides) and the detection limit of the analytical system was determined equal to 4 x 10 -11 mol.L -1 for plutonium. This result exhibits a gain in detection limit of a factor higher than 10 4 compared to the capillary electrophoresis in standard detection (UV). The studies were made in order to check the capacity of the CE / ICP-MS coupling as a speciation instrument for actinides at trace level and to define the associated analytical procedures. The coupling turned out to be a suited instrument for the determination of absolute electrophoretic mobilities at infinite dilution (physico-chemical property which allows to predict the migration time of an ion under an electrical field in a given electrolyte), for the determination of thermodynamic constants and for the separation of different actinide oxidation states in solution. (author)

  14. Quantification of Stable Isotope Traces Close to Natural Enrichment in Human Plasma Metabolites Using Gas Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Krämer, Lisa; Jäger, Christian; Trezzi, Jean-Pierre; Jacobs, Doris M; Hiller, Karsten

    2018-02-14

    Currently, changes in metabolic fluxes following consumption of stable isotope-enriched foods are usually limited to the analysis of postprandial kinetics of glucose. Kinetic information on a larger diversity of metabolites is often lacking, mainly due to the marginal percentage of fully isotopically enriched plant material in the administered food product, and hence, an even weaker 13 C enrichment in downstream plasma metabolites. Therefore, we developed an analytical workflow to determine weak 13 C enrichments of diverse plasma metabolites with conventional gas chromatography-mass spectrometry (GC-MS). The limit of quantification was increased by optimizing (1) the metabolite extraction from plasma, (2) the GC-MS measurement, and (3) most importantly, the computational data processing. We applied our workflow to study the catabolic dynamics of 13 C-enriched wheat bread in three human subjects. For that purpose, we collected time-resolved human plasma samples at 16 timepoints after the consumption of 13 C-labeled bread and quantified 13 C enrichment of 12 metabolites (glucose, lactate, alanine, glycine, serine, citrate, glutamate, glutamine, valine, isoleucine, tyrosine, and threonine). Based on isotopomer specific analysis, we were able to distinguish catabolic profiles of starch and protein hydrolysis. More generally, our study highlights that conventional GC-MS equipment is sufficient to detect isotope traces below 1% if an appropriate data processing is integrated.

  15. Trace determination of the flame retardant tetrabromobisphenol A in the atmosphere by gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Xie Zhiyong; Ebinghaus, Ralf; Lohmann, Rainer; Heemken, Olaf; Caba, Armando; Puettmann, Wilhelm

    2007-01-01

    A simple and effective method has been developed for analysis of the flame retardant tetrabromobisphenol A (TBBPA) in environmental samples by using modified soxhlet extraction in combination with silica gel clean-up, derivatization with silylation reagent and gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring mode (SIM). Satisfactory recoveries were achieved for the large volume sampling, soxhlet extraction and silica gel clean-up. The overall recovery is 79 ± 1%. The derivatization procedure is simple and fast, and produces stable TBBPA derivative. GC-MS with electronic impact (EI) ionization mode shows better detection power than using negative chemical ionization (NCI) mode. EI gives a method detection limit of 0.04 pg m -3 and enables to determine trace TBBPA in ambient air in remote area. The method was successfully applied to the determination of TBBPA in atmospheric samples collected over land and coastal regions. The concentrations of TBBPA ranged from below the method detection limit (0.04 pg m -3 ) to 0.85 pg m -3 . A declining trend with increasing latitude was present from the Wadden Sea to the Arctic. The atmospheric occurrence of TBBPA in the Arctic is significant and might imply that TBBPA has long-range transport potential

  16. Visualizing fossilization using laser ablation-inductively coupled plasma-mass spectrometry maps of trace elements in Late Cretaceous bones

    Science.gov (United States)

    Koenig, A.E.; Rogers, R.R.; Trueman, C.N.

    2009-01-01

    Elemental maps generated by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) provide a previously unavailable high-resolution visualization of the complex physicochemical conditions operating within individual bones during the early stages of diagenesis and fossilization. A selection of LA-ICP-MS maps of bones collected from the Late Cretaceous of Montana (United States) and Madagascar graphically illustrate diverse paths to recrystallization, and reveal unique insights into geochemical aspects of taphonomic history. Some bones show distinct gradients in concentrations of rare earth elements and uranium, with highest concentrations at external bone margins. Others exhibit more intricate patterns of trace element uptake related to bone histology and its control on the flow paths of pore waters. Patterns of element uptake as revealed by LA-ICP-MS maps can be used to guide sampling strategies, and call into question previous studies that hinge upon localized bulk samples of fossilized bone tissue. LA-ICP-MS maps also allow for comparison of recrystallization rates among fossil bones, and afford a novel approach to identifying bones or regions of bones potentially suitable for extracting intact biogeochemical signals. ?? 2009 Geological Society of America.

  17. Mass Spectrometry in Cosmetic Science: Advanced Ionization Techniques for Detecting Trace Molecules in or on Human Skin

    Science.gov (United States)

    Motoyama, Akira; Kihara, Keishi

    2017-01-01

    To provide safe and effective products to customers in the cosmetic industry, mass spectrometry (MS) is an indispensable analytical tool. In addition to its outstanding sensitivity and specificity, the method is applicable to a wide variety of compounds, which makes it irreplaceable for the development of cosmetics, which requires the analysis of complex systems. Because most cosmetic products are applied directly to the skin and function as they are designed, monitoring the molecular compositions of endogenous or exogenous compounds in or on the skin is crucial to ensure the safety and efficacy of a cosmetic product. Recent advancements in MS and ionization techniques, such as MS imaging and ambient ionization, now provide access to richer and deeper molecular information with less time and effort. This brief review discusses advanced ionization techniques that are currently used in the field of cosmetic science using two examples, namely, the use of desorption electrospray ionization and zero-volt paperspray ionization to detect trace molecules in or on human skin. PMID:28959516

  18. Complex Organic Molecules tracing shocks along the outflow cavity in the high-mass protostar IRAS 20126+4104

    Science.gov (United States)

    Palau, Aina; Walsh, Catherine; Sánchez-Monge, Álvaro; Girart, Josep M.; Cesaroni, Riccardo; Jiménez-Serra, Izaskun; Fuente, Asunción; Zapata, Luis A.; Neri, Roberto

    2017-01-01

    We report on subarcsecond observations of complex organic molecules (COMs) in the high-mass protostar IRAS 20126+4104 with the Plateau de Bure Interferometer in its most extended configurations. In addition to the simple molecules SO, HNCO and H213CO, we detect emission from CH3CN, CH3OH, HCOOH, HCOOCH3, CH3OCH3, CH3CH2CN, CH3COCH3, NH2CN, and (CH2OH)2. SO and HNCO present a X-shaped morphology consistent with tracing the outflow cavity walls. Most of the COMs have their peak emission at the putative position of the protostar, but also show an extension towards the south(east), coinciding with an H2 knot from the jet at about 800–1000 au from the protostar. This is especially clear in the case of H213CO and CH3OCH3. We fitted the spectra at representative positions for the disc and the outflow, and found that the abundances of most COMs are comparable at both positions, suggesting that COMs are enhanced in shocks as a result of the passage of the outflow. By coupling a parametric shock model to a large gas-grain chemical network including COMs, we find that the observed COMs should survive in the gas phase for ∼ 2000 yr, comparable to the shock lifetime estimated from the water masers at the outflow position. Overall, our data indicate that COMs in IRAS 20126+4104 may arise not only from the disc, but also from dense and hot regions associated with the outflow. PMID:28579644

  19. Trace level analysis of VOCs and semi-VOCs in aqueous solution using a direct insertion membrane probe and trap and release membrane introduction mass spectrometry

    OpenAIRE

    Mendes, MA; Eberlin, MN

    2000-01-01

    A new design for a trap and release membrane introduction mass spectrometry (T&R-MIMS) system using a removable direct insertion membrane probe (DIMP) for combined trace level analysis (low or sub ppb range) of volatile (VOC) and semi-volatile organic compounds (SVOCs) is reported. The system differs from the original T&R-MIMS system (M. Leth and F. R. Lauritsen, Rapid Commun. Mass Spectrom., 1995, 9, 591) as it uses a removable DIMP probe to place a capillary membrane loop inside the ion sou...

  20. Mass loading of selected major and trace elements in Lake Fork Creek near Leadville, Colorado, September-October 2001

    Science.gov (United States)

    Walton-Day, Katherine; Flynn, Jennifer L.; Kimball, Briant A.; Runkel, Robert L.

    2005-01-01

    load to the stream were the parts of the study reach containing inflow from the tribu-taries Halfmoon Creek (calcium) and Willow Creek (sulfate). The Arkansas River and its tributaries upstream from Lake Fork Creek were the source of most of the calcium (70 percent), sulfate (82 percent), manganese (77 percent), lead (78 percent), and zinc (95 percent) loads in the Arkansas River downstream from the Lake Fork confluence. In contrast, Lake Fork Creek was the major source of aluminum (68 percent), copper (65 percent), and iron (87 percent) loads to the Arkansas River downstream from the confluence. Attenuation was not important for calcium, sulfate, or iron. However, other metals loads were reduced up to 81 percent over the study reach (aluminum, 25 percent; copper, 20 percent; manganese, 81 percent; lead, 30 percent; zinc, 72 percent). Metal attenuation in the stream occurred primarily in three locations (1) the irrigation diversion ditch; (2) the beaver pond complex extending from upstream from the Colorado Gulch inflow to just downstream from that inflow; and (3) the stream reach that included the inflow from Willow Creek. The most likely attenuation mechanism is precipitation of metal oxides and hydroxides (primarily manganese), and sorption or coprecipitation of trace elements with the precipitating phase. A mass-balance calculation indicated that the wetland between the Dinero Tunnel and Lake Fork Creek removed iron, had little effect on zinc mass load, and was a source for, or was releasing, aluminum and manganese. In contrast, the wetland that occurred between the Siwatch Tunnel and Lake Fork Creek removed aluminum, iron, manganese, and zinc from the tunnel drainage before it entered the creek. Inflow from the National Fish Hatchery increased dissolved organic carbon concentrations in Lake Fork Creek and slightly changed the composition of the dissolved organic carbon. However, dissolved organic carbon loads increased in the stream reach downs

  1. Trace analysis of total naphthenic acids in aqueous environmental matrices by liquid chromatography/mass spectrometry-quadrupole time of flight mass spectrometry direct injection.

    Science.gov (United States)

    Brunswick, Pamela; Shang, Dayue; van Aggelen, Graham; Hindle, Ralph; Hewitt, L Mark; Frank, Richard A; Haberl, Maxine; Kim, Marcus

    2015-07-31

    A rapid and sensitive liquid chromatography quadrupole time of flight method has been established for the determination of total naphthenic acid concentrations in aqueous samples. This is the first methodology that has been adopted for routine, high resolution, high throughput analysis of total naphthenic acids at trace levels in unprocessed samples. A calibration range from 0.02 to 1.0μgmL(-1) total Merichem naphthenic acids was validated and demonstrated excellent accuracy (97-111% recovery) and precision (1.9% RSD at 0.02μgmL(-1)). Quantitative validation was also demonstrated in a non-commercial oil sands process water (OSPW) acid extractable organics (AEOs) fraction containing a higher percentage of polycarboxylic acid isomers than the Merichem technical mix. The chromatographic method showed good calibration linearity of ≥0.999 RSQ to 0.005μgmL(-1) total naphthenic acids with a precision <3.1% RSD and a calculated detection limit of 0.0004μgmL(-1) employing Merichem technical mix reference material. The method is well suited to monitoring naturally occurring and industrially derived naphthenic acids (and other AEOs) present in surface and ground waters in the vicinity of mining developments. The advantage of the current method is its direct application to unprocessed environmental samples and to examine natural naphthenic acid isomer profiles. It is noted that where the isomer profile of samples differs from that of the reference material, results should be considered semi-quantitative due to the lack of matching isomer content. The fingerprint profile of naphthenic acids is known to be transitory during aging and the present method has the ability to adapt to monitoring of these changes in naphthenic acid content. The method's total ion scan approach allows for data previously collected to be examined retrospectively for specific analyte mass ions of interest. A list of potential naphthenic acid isomers that decrease in response with aging is proposed

  2. Trace Element Analysis of Minerals in Magmatic-Hydrothermal Ores by Laser Ablation Inductively-Coupled Plasma Mass Spectrometry: Approaches and Opportunities

    Directory of Open Access Journals (Sweden)

    Nigel Cook

    2016-10-01

    Full Text Available Laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS has rapidly established itself as the method of choice for generation of multi-element datasets for specific minerals, with broad applications in Earth science. Variation in absolute concentrations of different trace elements within common, widely distributed phases, such as pyrite, iron-oxides (magnetite and hematite, and key accessory minerals, such as apatite and titanite, can be particularly valuable for understanding processes of ore formation, and when trace element distributions vary systematically within a mineral system, for a vector approach in mineral exploration. LA-ICP-MS trace element data can assist in element deportment and geometallurgical studies, providing proof of which minerals host key elements of economic relevance, or elements that are deleterious to various metallurgical processes. This contribution reviews recent advances in LA-ICP-MS methodology, reference standards, the application of the method to new mineral matrices, outstanding analytical uncertainties that impact on the quality and usefulness of trace element data, and future applications of the technique. We illustrate how data interpretation is highly dependent on an adequate understanding of prevailing mineral textures, geological history, and in some cases, crystal structure.

  3. Improved immobilization of 8-hydroxyquinoline on polyacrylonitrile fiber and application of the material to the determination of trace metals in seawater by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Wen, Bei; Shan, Xiao-Quan

    2002-11-01

    A modified synthetic method has been developed for immobilization of 8-hydroxyquinoline on polyacrylonitrile fiber. The synthetic conditions, e.g. reagent concentration, reaction temperature and time, were optimized. The features of the newly-modified fiber are higher exchange capacity compared with most other materials containing immobilized 8-hydroxyquinoline, better mechanic characteristics, high stability at both high and low pH, and ease of synthesis. This modified fiber can concentrate and separate trace metals from matrices with higher concentrations of alkali and alkaline earth elements. To validate the characteristics of the modified fiber, trace metals Ag, Be, Cd, Co, Cu, Mn, Ni, Pb, and Zn in the certified reference materials river water (SLRS-4) and seawater (CASS-4, NASS-5, SLEW-3) were preconcentrated before determination by inductively coupled plasma mass spectrometry. Good agreement was obtained between the data obtained by this method and the certified values.

  4. Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

    Science.gov (United States)

    An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

  5. The airborne mass spectrometer AIMS – Part 2: Measurements of trace gases with stratospheric or tropospheric origin in the UTLS

    Directory of Open Access Journals (Sweden)

    T. Jurkat

    2016-04-01

    an isotopically labeled 34SO2 standard. In addition, we report on trace gas measurements of HONO, which is sensitive to the reaction with SF5−. The detection limit for the various trace gases is in the low 10 pptv range at a 1 s time resolution with an overall uncertainty of the measurement of the order of 20 %. AIMS has been integrated and successfully operated on the DLR research aircraft Falcon and HALO (High Altitude LOng range research aircraft. As an example, measurements conducted during the TACTS/ESMVal (Transport and Composition of the LMS/UT and Earth System Model Validation mission with HALO in 2012 are presented, focusing on a classification of tropospheric and stratospheric influences in the UTLS region. The combination of AIMS measurements with other measurement techniques yields a comprehensive picture of the sulfur, chlorine and reactive nitrogen oxide budget in the UTLS. The different trace gases measured with AIMS exhibit the potential to gain a better understanding of the trace gas origin and variability at and near the tropopause.

  6. Development and application of mass spectrometric techniques for ultra-trace determination of236U in environmental samples-A review.

    Science.gov (United States)

    Bu, Wenting; Zheng, Jian; Ketterer, Michael E; Hu, Sheng; Uchida, Shigeo; Wang, Xiaolin

    2017-12-01

    Measurements of the long-lived radionuclide 236 U are an important endeavor, not only in nuclear safeguards work, but also in terms of using this emerging nuclide as a tracer in chemical oceanography, hydrology, and actinide sourcing. Depending on the properties of a sample and its neutron irradiation history, 236 U/ 238 U ratios from different sources vary significantly. Therefore, this ratio can be treated as an important fingerprint for radioactive source identification, and in particular, affords a definitive means of discriminating between naturally occurring U and specific types of anthropogenic U. The development of mass spectrometric techniques makes it possible to determine ultra-trace levels of 236 U in environmental samples. In this paper, we review the current status of mass spectrometric approaches for determination of 236 U in environmental samples. Various sample preparation methods are summarized and compared. The mass spectrometric techniques emphasized herein are thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (ICP-MS) and accelerator mass spectrometry (AMS). The strategies or principles used by each technique for the analysis of 236 U are described. The performances of these techniques in terms of abundance sensitivity and detection limit are discussed in detail. To date, AMS exhibits the best capability for ultra-trace determinations of 236 U. The levels and behaviors of 236 U in various environmental media are summarized and discussed as well. Results suggest that 236 U has an important, emerging role as a tracer for geochemical studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Characterization of flux-grown Trace-element-doped titanite using the high-mass-resolution ion microprobe (SHRIMP-RG)

    Science.gov (United States)

    Mazdab, F.K.

    2009-01-01

    Crystals of titanite can be readily grown under ambient pressure from a mixture of CaO, TiO2 and SiO2 in the presence of molten sodium tetraborate. The crystals produced are euhedral and prismatic, lustrous and transparent, and up to 5 mm in length. Titanite obtained by this method contains approximately 4300 ppm Na and 220 ppm B contributed from the flux. In addition to dopant-free material, titanite containing trace alkali and alkaline earth metals (K, Sr, Ba), transition metals (Sc, Cr, Ni, Y, Zr, Nb, Hf and Ta), rare-earth elements (REE), actinides (Th, U) and p-block elements (F, S, Cl, Ge, Sn and Pb) have been prepared using the same procedure. Back-scattered electron (BSE) imaging accompanied by ion-microprobe (SHRIMP-RG) analysis confirms significant incorporation of selected trace-elements at structural sites. Regardless of some zonation, the large size of the crystals and broad regions of chemical homogeneity make these crystals useful as experimental starting material, and as matrix-matched trace-element standards for a variety of microbeam analytical techniques where amorphous titanite glass, heterogeneous natural titanite or a non-titanite standard may be less than satisfactory. Trace-element-doped synthetic crystals can also provide a convenient proxy for a better understanding of trace-element incorporation in natural titanite. Comparisons with igneous, authigenic and high-temperature metasomatic titanite are examined. The use of high-mass-resolution SIMS also demonstrates the analytical challenges inherent to any in situ mass-spectrometry-based analysis of titanite, owing to the production of difficult-to-resolve molecular interferences. These interferences are dominated by Ca-Ca, Ca-Ti and Ti-Ti dimers that are significant in the mass range of 80-100, affecting all isotopes of Sr and Zr, as well as 89Y and 93Nb. Methods do exist for the evaluation of interferences by these dimers and of polyatomic interferences on the LREE.

  8. Characterization of national food agency shrimp and plaice reference materials for trace elements and arsenic species by atomic and mass spectrometric techniques

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pedersen, Gitte Alsing; McLaren, J. W.

    1997-01-01

    , drying, milling and sieving to collect the fraction of particles less than 150 mu m in sizer In this fraction the trace elements were homogeneously distributed using a 400 mg sample intake for analysis, The total track element concentrations were determined by graphite furnace and cold vapour atomic...... absorption spectrometry, inductively coupled plasma mass spectrometry (ICP-MS) and isotope dilution ICP-MS. The contents of arsenobetaine and the tetramethylarsonium ion were determined by cation exchange high performance liquid chromatography (HPLC) coupled with ICP-MS, or coupled with ion-spray (IS) tandem...

  9. Trace elements in free-range hen eggs in the Campania region (Italy) analyzed by inductively coupled plasma mass spectrometry (ICP-MS).

    Science.gov (United States)

    Esposito, Mauro; Cavallo, Stefania; Chiaravalle, Eugenio; Miedico, Oto; Pellicanò, Roberta; Rosato, Guido; Sarnelli, Paolo; Baldi, Loredana

    2016-06-01

    Eggs from hens raised on rural or domestic farms are a good indicator of environmental contamination, as the hens are in close contact with the ground and the air and can therefore accumulate heavy metals and other toxic contaminants from the environment as well as from the diet. In this paper, we report the results of the determination of 19 trace elements (As, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se, Sn, Sr, Tl, U, V, Zn) in 39 hen egg samples collected from domestic poultry farms in the territory dubbed the "Land of fires" in the Campania region (Italy). This area is characterized by environmental problems caused by the illegal dumping of industrial or domestic waste in fields or by roadsides. In some cases, these wastes have been burned, thereby spreading persistent contaminants into the atmosphere. The content of trace elements in whole egg samples was determined by mass spectrometer after a microwave-assisted digestion procedure. Because European legislation does not indicate maximum values of these elements in this foodstuff, the results were compared with the content of trace elements reported in literature for eggs, in particular home-produced eggs, in various countries. In some cases (Cd, Cu, Ni, Mn), the content determined in this study was in line with those reported elsewhere, in other cases (Pb, Cr), lower values were found.

  10. Trace amounts of rare earth elements in high purity samarium oxide by sector field inductively coupled plasma mass spectrometry after separation by HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira, W.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil) and Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), 05409-002 Sao Paulo, SP (Brazil)]. E-mail: walter.pedreira@fundacentro.gov.br; Queiroz, C.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Abrao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Rocha, S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Vasconcellos, M.E. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Boaventura, G.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil); Pimentel, M.M. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil)

    2006-07-20

    Today there is an increasing need for high purity rare earth compounds in various fields, the optical, the electronics, the ceramic, the nuclear and geochemistry. Samarium oxide has special uses in glass, phosphors, lasers and thermoelectric devices. Calcium chloride crystals treated with samarium have been employed in lasers, which produce light beams intense enough to burn metal. In general, the inductively coupled plasma mass spectrometry (ICP-MS) presents some advantages for trace element analysis, due to high sensitivity and resolution, when compared with other analytical techniques such as ICP optical emission spectrometry (ICP-OES). In this work, sector field inductively coupled plasma mass spectrometry was used. Sixteen elements (Sc, Y and 14 lanthanides) were determined selectively with the ICP-MS system using a concentration gradient method. The detection limits with the ICP-MS system were about 0.2 (La) pg mL{sup -1} to 8 (Gd) pg mL{sup -1}. The %R.S.D. of the methods varying between 0.9 and 1.5% for a set of five (n = 5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two high pure samarium oxides samples (IPEN and JMC) was performed. IPEN's material is highly pure (>99.99%) and was successfully analyzed without spectral interference (MO{sup +} and MOH{sup +})

  11. Selected ion flow tube mass spectrometry for on-line trace gas analysis in biology and medicine

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Smith, D.

    2007-01-01

    Roč. 13, č. 1 (2007), s. 77-82 ISSN 1469-0667 R&D Projects: GA ČR GA202/06/0776 Institutional research plan: CEZ:AV0Z40400503 Keywords : selected ion flow tube mass spectroscopy (SIFT-MS) * breath analysis * breath metabolities * flowing afterglow mass spectrometry (FA-MS) Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.198, year: 2007

  12. Cadmium (II) imprinted 3-mercaptopropyltrimethoxysilane coated stir bar for selective extraction of trace cadmium from environmental water samples followed by inductively coupled plasma mass spectrometry detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Nan [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu Bin, E-mail: binhu@whu.edu.cn [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2012-04-20

    Graphical abstract: Ion imprinted 3-mercaptopropyltrimethoxysilane (MPTS) coated stir bar for selective extraction of trace Cd(II). Highlights: Black-Right-Pointing-Pointer Ion imprinted polymers were proposed as the coating for SBSE for the first time. Black-Right-Pointing-Pointer Cd(II) imprinted MPTS-silica coating was prepared by a double-imprinting concept. Black-Right-Pointing-Pointer A novel method of SBSE-ICP-MS was developed for the determination of Cd in waters. Black-Right-Pointing-Pointer This method is rapid, selective, sensitive and applicable for determining trace Cd(II) in waters. - Abstract: Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol-gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5 {mu}g and 0.8 {mu}g bar{sup -1}. The detection limit (3{sigma}) based on three times standard deviations of the method blanks by 7 replicates was 4.40 ng L{sup -1} and the relative standard

  13. Ultra-trace determination of plutonium in marine samples using multi-collector inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Lindahl, Patric; Keith-Roach, Miranda; Worsfold, Paul; Choi, Min-Seok; Shin, Hyung-Seon; Lee, Sang-Hoon

    2010-06-25

    Sources of plutonium isotopes to the marine environment are well defined, both spatially and temporally, which makes Pu a potential tracer for oceanic processes. This paper presents the selection, optimisation and validation of a sample preparation method for the ultra-trace determination of Pu isotopes ((240)Pu and (239)Pu) in marine samples by multi-collector (MC) ICP-MS. The method was optimised for the removal of the interference from (238)U and the chemical recovery of Pu. Comparison of various separation strategies using AG1-X8, TEVA, TRU, and UTEVA resins to determine Pu in marine calcium carbonate samples is reported. A combination of anion-exchange (AG1-X8) and extraction chromatography (UTEVA/TRU) was the most suitable, with a radiochemical Pu yield of 87+/-5% and a U decontamination factor of 1.2 x 10(4). Validation of the method was accomplished by determining Pu in various IAEA certified marine reference materials. The estimated MC-ICP-MS instrumental limit of detection for (239)Pu and (240)Pu was 0.02 fg mL(-1), with an absolute limit of quantification of 0.11 fg. The proposed method allows the determination of ultra-trace Pu, at femtogram levels, in small size marine samples (e.g., 0.6-2.0 g coral or 15-20 L seawater). Finally, the analytical method was applied to determining historical records of the Pu signature in coral samples from the tropical Northwest Pacific and (239+240)Pu concentrations and (240)Pu/(239)Pu atom ratios in seawater samples as part of the 2008 GEOTRACES intercalibration exercise. Copyright 2010 Elsevier B.V. All rights reserved.

  14. Ultra-trace determination of plutonium in marine samples using multi-collector inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Lindahl, Patric; Keith-Roach, Miranda; Worsfold, Paul; Choi, Min-Seok; Shin, Hyung-Seon; Lee, Sang-Hoon

    2010-01-01

    Sources of plutonium isotopes to the marine environment are well defined, both spatially and temporally, which makes Pu a potential tracer for oceanic processes. This paper presents the selection, optimisation and validation of a sample preparation method for the ultra-trace determination of Pu isotopes ( 240 Pu and 239 Pu) in marine samples by multi-collector (MC) ICP-MS. The method was optimised for the removal of the interference from 238 U and the chemical recovery of Pu. Comparison of various separation strategies using AG1-X8, TEVA, TRU, and UTEVA resins to determine Pu in marine calcium carbonate samples is reported. A combination of anion-exchange (AG1-X8) and extraction chromatography (UTEVA/TRU) was the most suitable, with a radiochemical Pu yield of 87 ± 5% and a U decontamination factor of 1.2 x 10 4 . Validation of the method was accomplished by determining Pu in various IAEA certified marine reference materials. The estimated MC-ICP-MS instrumental limit of detection for 239 Pu and 240 Pu was 0.02 fg mL -1 , with an absolute limit of quantification of 0.11 fg. The proposed method allows the determination of ultra-trace Pu, at femtogram levels, in small size marine samples (e.g., 0.6-2.0 g coral or 15-20 L seawater). Finally, the analytical method was applied to determining historical records of the Pu signature in coral samples from the tropical Northwest Pacific and 239+240 Pu concentrations and 240 Pu/ 239 Pu atom ratios in seawater samples as part of the 2008 GEOTRACES intercalibration exercise.

  15. Developments and trends in inductively coupled plasma mass spectrometry and its influence on the recent advances in trace element analysis

    International Nuclear Information System (INIS)

    Balaram, V.

    1995-01-01

    A brief introduction to the various instrumental methods such as atomic absorption spectrometry, x-ray fluorescence spectrometry, neutron activation analysis, inductively coupled plasma atomic emission spectrometry, thermal ionization mass spectrometry, etc. are presented highlighting their relative merits and demerits. The history and developments of inductively coupled plasma mass spectrometry (ICP-MS) and its advantages and limitations over other multi-element instrumental techniques are reviewed. Extended capabilities by hyphenating ICP-MS to various other well-known sample introduction techniques such as flow-injection, electrothermal vaporization, chromatographic methods and laser ablation are discussed in brief. The recent development of high resolution multi-collector double-focusing magnetic mass spectrometer with inductively coupled plasma at atmospheric pressure as source is also discussed. Some of the areas where more developments can be expected in future are suggested. (author). 77 refs., 4 tabs., 3 figs

  16. Trace analysis of actinides in the environment using resonance ionization mass spectrometry; Spurenanalyse von Aktiniden in der Umwelt mittels Resonanzionisations-Massenspektrometrie

    Energy Technology Data Exchange (ETDEWEB)

    Raeder, Sebastian

    2011-04-12

    In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10{sup 4}-10{sup 5} atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope {sup 236}U a detection limit down to 10{sup -9} for the isotope ratio N ({sup 236}U)/N ({sup 238}U) could be determined.

  17. The chemical speciation and analysis of trace elements in sediment with Neutron Activation Analytical method(NAA) and atomic mass spectrometry

    International Nuclear Information System (INIS)

    Nam, Sang-Ho; Kim, Jae-Jin; Chung, Yong-Sam; Kim, Sun-Ha

    2003-01-01

    In this research, first of all, the analytical methods for the determination of major elements in sediment have been developed with ICP-MS (Inductively Coupled Plasma Mass Spectrometry). The analytical results of major elements (Al, Ca, K, Fe, Mg) with Cool ICP-MS were much better than those with normal ICP-MS. The analytical results were compared with those of NAA (Neutron Activation Analysis). NAA were a little superior to ICP-MS for the determination of major elements in sediment as a non-destructive trace analytical trace analytical method. The analytical methods for the determination of minor elements (Cr, Ce, U, Co, Pb, As, Se) have been also developed with ICP-MS. The analytical results by standard calibration curve with ICP-MS were not accurate due to the matrix interferences. Thus, the internal standard method was applied, then the analytical results for minor elements with ICP-MS were greatly improved. The analytical results obtained by ICP-MS were compared with those obtained by NAA. It showed that the two analytical methods have great capabilities for the determination of minor elements in sediments. Accordingly, the NAA will plan an important role in analysis of environment sample with complex matrix. ICP-MS also will play an important role because it has a great capability for the determination of Pb that could not be determined by NAA

  18. Identification of trace volatile compounds in freshly distilled Calvados and Cognac using preparative separations coupled with gas chromatography-mass spectrometry.

    Science.gov (United States)

    Ledauphin, Jérôme; Saint-Clair, Jean-François; Lablanquie, Odile; Guichard, Hugues; Founier, Nicole; Guichard, Elisabeth; Barillier, Daniel

    2004-08-11

    Gas chromatography coupled with mass spectrometry (GC-MS) using both electron impact and chemical ionization detection modes led to the determination of the volatile composition of two samples of freshly distilled Cognac and two samples of freshly distilled Calvados. A total of 169 volatile compounds were directly identified in dichloromethane extracts obtained by liquid-liquid extraction. Trace compounds present in both spirits were characterized with the help of preparative separations. In a first step, groups of compounds were separated by preparative GC, and the fractions were analyzed on a polar stationary phase by GC-MS. In a second step, silica gel fractionation was used to separate them by polarity. In this study, 331 compounds, of which 162 can be considered as trace compounds, were characterized in both freshly distilled Cognac and Calvados. Of these, 39 are common to both spirits; 30 are specific to Cognac with numerous hexenyl esters and norisoprenoidic derivatives, whereas 93 are specific to Calvados with compounds such as unsaturated alcohols, phenolic derivatives, and unsaturated aldehydes.

  19. Method for detection of trace metal and metalloid contaminants in coal-generated fuel gas using gas chromatography/ion trap mass spectrometry.

    Science.gov (United States)

    Rupp, Erik C; Granite, Evan J; Stanko, Dennis C

    2010-07-15

    There exists an increasing need to develop a reliable method to detect trace contaminants in fuel gas derived from coal gasification. While Hg is subject to current and future regulations, As, Se, and P emissions may eventually be regulated. Sorbents are the most promising technology for the removal of contaminants from coal-derived fuel gas, and it will be important to develop a rapid analytical detection method to ensure complete removal and determine the ideal time for sorbent replacement/regeneration in order to reduce costs. This technical note explores the use of a commercial gas chromatography/ion trap mass spectrometry system for the detection of four gaseous trace contaminants in a simulated fuel gas. Quantitative, repeatable detection with limits at ppbv to ppmv levels were obtained for arsine (AsH(3)), phosphine (PH(3)), and hydrogen selenide (H(2)Se), while qualitative detection was observed for mercury. Decreased accuracy and response caused by the primary components of fuel gas were observed.

  20. Direct detection of benzene, toluene, and ethylbenzene at trace levels in ambient air by atmospheric pressure chemical ionization using a handheld mass spectrometer.

    Science.gov (United States)

    Huang, Guangming; Gao, Liang; Duncan, Jason; Harper, Jason D; Sanders, Nathaniel L; Ouyang, Zheng; Cooks, R Graham

    2010-01-01

    The capabilities of a portable mass spectrometer for real-time monitoring of trace levels of benzene, toluene, and ethylbenzene in air are illustrated. An atmospheric pressure interface was built to implement atmospheric pressure chemical ionization for direct analysis of gas-phase samples on a previously described miniature mass spectrometer (Gao et al. Anal. Chem.2006, 78, 5994-6002). Linear dynamic ranges, limits of detection and other analytical figures of merit were evaluated: for benzene, a limit of detection of 0.2 parts-per-billion was achieved for air samples without any sample preconcentration. The corresponding limits of detection for toluene and ethylbenzene were 0.5 parts-per-billion and 0.7 parts-per-billion, respectively. These detection limits are well below the compounds' permissible exposure levels, even in the presence of added complex mixtures of organics at levels exceeding the parts-per-million level. The linear dynamic ranges of benzene, toluene, and ethylbenzene are limited to approximately two orders of magnitude by saturation of the detection electronics. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  1. Rapid characterization of trace aflatoxin B1 in groundnuts, wheat and maize by dispersive liquid-liquid microextraction followed by direct electrospray probe tandem mass spectrometry.

    Science.gov (United States)

    Satarpai, Thiphol; Siripinyanond, Atitaya; Su, Hung; Shiea, Jentaie

    2017-04-30

    Aflatoxins are poisonous and cancer-related chemical compounds commonly found in crops and plants. Aflatoxin B 1 is the most toxic compound among aflatoxins and has been classified as group 1 carcinogenic to humans, especially in liver cancer. Herein, an ambient mass spectrometric method was developed for rapid characterization of trace aflatoxin B 1 in peanuts. Direct electrospray probe tandem mass spectrometry (DEP-MS/MS) was used to detect aflatoxin B 1 in peanuts. To avoid the matrix effect, the aflatoxin B 1 in the samples was extracted and concentrated by dispersive liquid-liquid microextraction. The mass spectrometer was operated in the positive ion mode to monitor the intact molecular ion (m/z 313, MH + ) and product ion (m/z 241) of aflatoxin B 1 using multiple reaction monitoring. Since no clean-up procedure of the sample was required, the sampling step and the subsequent mass spectrometric detection of the aflatoxin B 1 was completed in less than 5 min. The limit of detection of aflatoxin B 1 is at the sub-ppb level. The results obtained by DEP-MS/MS were also validated by liquid chromatography/tandem mass spectrometry (LC/MS/MS). Recovery of aflatoxin B 1 in the sample was evaluated by analyzing spiked aflatoxin B 1 with LC/MS/MS to be 85% and DEP-MS/MS to be 84%. DEP-MS/MS combined with a simple dispersive liquid-liquid microextraction procedure was successfully used for the quantitative analysis of AFB 1 in nut samples. Due to its high efficiency, it is promising in providing important toxicological information for food safety in the real world. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Development and method of use of a mass spectrometric isotope dilution analysis within the use of negative thermoionisation for determination of boron traces

    International Nuclear Information System (INIS)

    Zeininger, H.

    1984-01-01

    A mass spectrometric trace boron determination using negative thermionisation was developed. It is based on the determination of the ratio of BO 2 - isotopes ( 10 B and 11 B). A high stability and a constant intensity at a given temperature of the BO 2 - ion currents allow for a computer controlled measurement with a programmed heating. The reproducibility lies at around 0,004-0,08%. The boron determination using Mels potentiometry with a BF 4 - -ion selective electrode was used as an analytical comparison method. The MS-IDA was first used on metal samples, such as Al, Zr, and steel. Later on the boron in reagents, biological material (milk powder, spinach, water plants) and water were determined. For this material-dependent hydrolysation and separation procedures were worked out. The MS-IDA in comparison to all other analytical methods used by other collaborators offers the greatest accuracy. (RB) [de

  3. Note: Possibilities of detecting the trace-level erosion products from an electric propulsion hollow cathode plasma source by the method of time-of-flight mass spectrometry

    Science.gov (United States)

    Ning, Zhong-Xi; Zhang, Hai-Guang; Zhu, Xi-Ming; Jiang, Bin-Hao; Zhou, Zhong-Yue; Yu, Da-Ren; An, Bing-Jian; Wang, Yan-Fei

    2018-02-01

    A hollow cathode produces electrons which neutralize ions from electric propulsion thrusters. After hundreds to thousands of hours of operation in space, the cathode materials can be significantly eroded due to ion bombardment. As a result, the electric propulsion system performance will be obviously changed or even fail. In this work, the erosion products from a LaB6 hollow cathode (widely used presently in electric propulsion systems) are studied by using a specific detection system, which consists of a molecular beam sampler and a time-of-flight mass spectrometer. This system measures trace-level-concentration (10-6-10-3) products. Boron (B), tantalum (Ta), and tungsten (W)—originating from the emitter, keeper, and orifice of the hollow cathode—are measured. It is found that the erosion rate is significantly influenced by the gas flow rate to the cathode.

  4. Laser post-ionization secondary neutral mass spectrometry for ultra-trace analysis of samples from space return missions

    International Nuclear Information System (INIS)

    Veryovkin, Igor V.; Calaway, Wallis F.; Emil Tripa, C.; Moore, Jerry F.; Wucher, Andreas; Pellin, Michael J.

    2005-01-01

    A new generation of secondary neutral mass spectrometry (SNMS) instruments has been developed that is especially designed for laser post-ionization (LPI). These instruments combine high useful yield and high background discrimination. Results presented here demonstrate that these instruments can detect one in every four atoms removed from a samples surface - a greater than one order of magnitude improvement over current large frame secondary ion mass spectrometry instruments. Because of their high sensitivity, these new LPI-SNMS instruments are especially amenable to analysis of samples of limited size and rare one-of-a-kind samples. Such an application is analysis of samples returned to Earth from space by the Genesis and Stardust Discovery missions of NASA

  5. Direct determination of trace phthalate esters in alcoholic spirits by spray-inlet microwave plasma torch ionization tandem mass spectrometry.

    Science.gov (United States)

    Miao, Meng; Zhao, Gaosheng; Xu, Li; Dong, Junguo; Cheng, Ping

    2018-03-01

    A direct analytical method based on spray-inlet microwave plasma torch tandem mass spectrometry was applied to simultaneously determine 4 phthalate esters (PAEs), namely, benzyl butyl phthalate, diethyl phthalate, dipentyl phthalate, and dodecyl phthalate with extremely high sensitivity in spirits without sample treatment. Among the 4 brands of spirit products, 3 kinds of PAE compounds were directly determined at very low concentrations from 1.30 to 114 ng·g -1 . Compared with other online and off-line methods, the spray-inlet microwave plasma torch tandem mass spectrometry technique is extremely simple, rapid, sensitive, and high efficient, providing an ideal screening tool for PAEs in spirits. Copyright © 2017 John Wiley & Sons, Ltd.

  6. Detection of trace organics in Mars analog samples containing perchlorate by laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Li, Xiang; Danell, Ryan M; Brinckerhoff, William B; Pinnick, Veronica T; van Amerom, Friso; Arevalo, Ricardo D; Getty, Stephanie A; Mahaffy, Paul R; Steininger, Harald; Goesmann, Fred

    2015-02-01

    Evidence from recent Mars missions indicates the presence of perchlorate salts up to 1 wt % level in the near-surface materials. Mixed perchlorates and other oxychlorine species may complicate the detection of organic molecules in bulk martian samples when using pyrolysis techniques. To address this analytical challenge, we report here results of laboratory measurements with laser desorption mass spectrometry, including analyses performed on both commercial and Mars Organic Molecule Analyzer (MOMA) breadboard instruments. We demonstrate that the detection of nonvolatile organics in selected spiked mineral-matrix materials by laser desorption/ionization (LDI) mass spectrometry is not inhibited by the presence of up to 1 wt % perchlorate salt. The organics in the sample are not significantly degraded or combusted in the LDI process, and the parent molecular ion is retained in the mass spectrum. The LDI technique provides distinct potential benefits for the detection of organics in situ on the martian surface and has the potential to aid in the search for signs of life on Mars.

  7. Lithophile Trace Element Mass Balance in Spinel Lherzolites from Borée, Massif Central, France: the Effects of Melt Impregnation on Variably Depleted Peridotites

    Science.gov (United States)

    Barnett, C. J.; Harvey, J.; Morgan, D. J.; Hammond, S.; Walshaw, R.

    2014-12-01

    Isotopic and elemental investigations of peridotite xenoliths can be used to model the timing and degree of melt extraction in the mantle. However, the primary melt depletion signature preserved in these xenoliths can be overprinted by subsequent metasomatism and melt-rock interactions, which tend to obscure the degree of original melt depletion either through the crystallisation of secondary phases or through the pervasive addition of lithophile element-rich basalt or its derivatives. Anhydrous spinel lherzolite xenoliths from the volcanic Maar de Borée in the French Massif Central have textures that vary from equigranular to protogranular. There is clear evidence of melt infiltration of up to several modal per cent in an anastomosing network of veins and stringers. Bulk-rock major elements and compatible trace element concentrations suggest that the Borée peridotites are genetically related by differing degrees of melt extraction, but the influence of melt infiltration, clearly visible at the thin section scale, and likely comprising several modal percent of the rock, makes this melt depletion difficult to quantify accurately. Some incompatible trace element concentrations in clinopyroxenes are consistent with melt depletion, while elevated (La/Yb)Nratios in others are clearly indicative of cryptic metasomatism and suggest yet another style of metasomatism. Furthermore, infiltrated melt along grain boundaries and in interstitial pockets disturbs the incompatible element mass balance, further obscuring the true nature of the prior melt depletion event(s). Quantitative lithophile element mass balance calculations will allow the effects of melt infiltration to be determined and stripped away from bulk-rock xenolith compositions, permitting a more realistic appraisal of the original melt depletion event.

  8. Cyclic organic peroxides identification and trace analysis by Raman microscopy and open-air chemical ionization mass spectrometry

    Science.gov (United States)

    Pena-Quevedo, Alvaro Javier

    The persistent use of cyclic organic peroxides in explosive devices has increased the interest in study these compounds. Development of methodologies for the detection of triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) has become an urgent priority. However, differences in physical properties between cyclic organic peroxides make difficult the development of a general method for peroxide analysis and detection. Following this urgency, the first general technique for the analysis of any peroxide, regarding its structural differences is reported. Characterization and detection of TATP and HMTD was performed using an Open-Air Chemical Ionization High-Resolution Time-of-Flight Mass Spectrometer. The first spectrometric analysis for tetramethylene diperoxide dicarbamide (TMDD) and other nitrogen based peroxides using Raman Microscopy and Mass Spectrometry is reported. Analysis of cyclic peroxides by GC-MS was also conducted to compare results with OACI-HRTOF data. In the OACI mass spectrum, HMTD showed a clear signal at m/z 209 MH + and a small adduct peak at m/z 226 [M+NH4]+ that allowed its detection in commercial standard solutions and lab made standards. TMDD presented a molecular peak of m/z 237 MH+ and an adduct peak of m/z 254 [M+NH4]+. TATP showed a single peak at m/z 240 [M+NH4]+, while the peak of m/z 223 or 222 was completely absent. This evidence suggests that triperoxides are stabilized by the ammonium ion. TATP samples with deuterium enrichment were analyzed to compare results that could differentiate from HMTD. Raman microscopy was used as a complementary characterization method and was an essential tool for cyclic peroxides identification, particularly for those which could not be extensively purified. All samples were characterized by Raman spectroscopy to confirm the Mass Spectrometry results. Peroxide O-O vibrations were observed around 750-970 cm-1. D18-TATP studies had identified ketone triperoxide nu(O-O) vibration around

  9. Golf ball-assisted electrospray ionization of mass spectrometry for the determination of trace amino acids in complex samples.

    Science.gov (United States)

    Li, Yen-Hsien; Chen, Chung-Yu; Kuo, Cheng-Hsiung; Lee, Maw-Rong

    2016-09-28

    During the electrospray ionization (ESI) process, ions move through a heated capillary aperture to be detected on arrival at a mass analyzer. However, the ESI process creates an ion plume, which expands into an ion cloud with an area larger than that of the heated capillary aperture, significantly contributing to an ion loss of 50% due to coulombic repulsion. The use of DC and RF fields to focus ions from the ion source into the vacuum chamber has been proposed in the literature, but the improvement of ion transmission efficiency is limited. To improve ion transmission, in this study we propose a novel method using a home-made golf ball positioned between the ion source and the inlet of the mass analyzer to hydrodynamically focus the ions passing through the golf ball. The ion plume produced by the ESI process passes through the golf ball will reduce the size of the ion cloud then be focused and most of them flowed into the mass analyzer. Therefore, the sensitivity will be improved, the aim of this investigation is to study the enhancing of the signal using golf ball-assisted electrospray ionization liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine 20 trace amino acids in complex samples, including tea, urine and serum. The results showed that the analytical performance of the determination of the 20 amino acids in tea, urine and serum samples using the home-made golf ball-assisted ESI source is better than that of a commercial ESI source. The signal intensities of the 20 amino acids were enhanced by factors of 2-2700, 11-2525, and 31-342680 in oolong tea, urine and serum analyses, respectively. The precision of the proposed method ranged from 1-9%, 0.4-9% and 0.4-8% at low, medium and high concentration levels of amino acids, respectively. The home-made golf ball-assisted ESI source effectively increased the signal intensity and enhanced the ion transmission efficiency and is also an easy, convenient and economical device. This technique can

  10. Characterization of key aerosol, trace gas and meteorological properties and particle formation and growth processes dependent on air mass origins in coastal Southern Spain

    Science.gov (United States)

    Diesch, J.; Drewnick, F.; Sinha, V.; Williams, J.; Borrmann, S.

    2011-12-01

    The chemical composition and concentration of aerosols at a certain site can vary depending on season, the air mass source region and distance from sources. Regardless of the environment, new particle formation (NPF) events are one of the major sources for ultrafine particles which are potentially hazardous to human health. Grown particles are optically active and efficient CCN resulting in important implications for visibility and climate (Zhang et al., 2004). The study presented here is intended to provide information about various aspects of continental, urban and marine air masses reflected by wind patterns of the air arriving at the measurement site. Additionally we will be focusing on NPF events associated with different types of air masses affecting their emergence and temporal evolution. Measurements of the ambient aerosol, various trace gases and meteorological parameters were performed within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from mid-November to mid-December 2008 at the atmospheric research station "El Arenosillo" located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean. Number and mass as well as PAH and black carbon concentrations were measured in PM1 and size distribution instruments covered the size range 6 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (AMS). In order to evaluate the characteristics of different air masses linking local and regional sources as well as NPF processes, characteristic air mass types were classified dependent on backwards trajectory pathways and local meteorology. Large nuclei mode concentrations in the number size distribution were found within continental and urban influenced air mass types due to frequently occurring NPF events. Exploring individual production and sink variables, sulfuric

  11. Application of mass spectrometric techniques for the trace analysis of short-lived iodine-containing volatiles emitted by seaweed.

    Science.gov (United States)

    Kundel, Michael; Thorenz, Ute R; Petersen, Jan H; Huang, Ru-Jin; Bings, Nicolas H; Hoffmann, Thorsten

    2012-04-01

    Knowledge of the composition and emission rates of iodine-containing volatiles from major widespread seaweed species is important for modeling the impact of halogens on gas-phase atmospheric chemistry, new particle formation, and climate. In this work, we present the application of mass spectrometric techniques for the quantification of short-lived iodine-containing volatiles emitted by eight different seaweeds from the intertidal zone of Helgoland, Germany. A previously developed online time-of-flight aerosol mass spectrometric method was used to determine I(2) emission rates and investigate temporally resolved emission profiles. Simultaneously, iodocarbons were preconcentrated on solid adsorbent tubes and quantified offline using thermodesorption-gas chromatography-mass spectrometry. The total iodine content of the seaweeds was determined using microwave-assisted tetramethylammonium hydroxide extraction followed by inductively coupled-plasma mass spectrometry analysis. The highest total iodine content was found in the Laminariales, followed by the brown algae Ascophyllum nodosum, Fucus vesiculosus, Fucus serratus, and both red algae Chondrus crispus and Delesseria sanguinea. Laminariales were found to be the strongest I(2) emitters. Time series of the iodine release of Laminaria digitata and Laminaria hyperborea showed a strong initial I(2) emission when first exposed to air followed by an exponential decline of the release rate. For both species, I(2) emission bursts were observed. For Laminaria saccharina und F. serratus, a more continuous I(2) release profile was detected, however, F. serratus released much less I(2). A. nodosum and F. vesiculosus showed a completely different emission behavior. The I(2) emission rates of these species were slowly increasing with time during the first 1 to 2 h until a more or less stable I(2) emission rate was reached. The lowest I(2) emission rates were detected for the red algae C. crispus and D. sanguinea. Total iodocarbon

  12. Mass

    International Nuclear Information System (INIS)

    Quigg, Chris

    2007-01-01

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  13. Trace isotope analysis using resonance ionization mass spectrometry based on isotope selection with doppler shift of laser ablated atoms

    International Nuclear Information System (INIS)

    Higuchi, Yuki; Watanabe, Kenichi; Kawarabayashi, Jun; Iguchi, Tetsuo

    2005-01-01

    We have proposed a novel isotope selective Resonance Ionization Mass Spectroscopy (RIMS) concept, which can avoid the Doppler broadening on solid sample direct measurement based on laser ablation technique. We have succeeded in experimentally demonstrating the principle of our RIMS concept. Through comparison between the simulated and experimental results, we have validated the simulation model. It would be concluded from these results that we could achieve the isotope selectivity defined as the ratio of 41 Ca to 40 Ca sensitivity to be 4.5x10 10 by adopting the multi-step excitation scheme in the present method. As future works, we will try to experimentally perform the multi-step excitation scheme and improve the detection efficiency by modifying the ion extraction configuration. (author)

  14. Trace-Level Screening of Chemicals Related to Clandestine Desomorphine Production with Ambient Sampling, Portable Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Seth E. Hall

    2017-01-01

    Full Text Available Desomorphine is a semisynthetic opioid that is responsible for the psychoactive effects of a dangerous homemade injectable mixture that goes by street name “Krokodil.” Desorption electrospray ionization (DESI and paper spray ionization (PSI are implemented on a portable mass spectrometer for the direct analysis of desomorphine and precursor reagent codeine from multiple substrates of potential relevance to clandestine drug laboratory synthesis and paraphernalia seizure. Minimal sample preparation required for analysis and portability of the instrument suggest the potential for rapid, on-site analysis of evidence, a highly desired benefit for forensic science and law enforcement practitioners. Both DESI-MS and PSI-MS can generate spectra consistent with preceding data obtained using traditional ionization methods, while demonstrating detection limits in the low- to sub-ng levels.

  15. Analysis of trace levels of sulfonamide and tetracycline antimicrobials in groundwater and surface water using solid-phase extraction and liquid chromatography/mass spectrometry

    Science.gov (United States)

    Lindsey, M.E.; Meyer, M.; Thurman, E.M.

    2001-01-01

    A method has been developed for the trace analysis of two classes of antimicrobials consisting of six sulfonamides (SAs) and five tetracyclines (TCs), which commonly are used for veterinary purposes and agricultural feed additives and are suspected to leach into ground and surface water. The method used solid-phase extraction and liquid chromatography/mass spectrometry (LC/MS) with positive ion electrospray. The unique combination of a metal chelation agent (Na2EDTA) with a macroporous copolymer resulted in quantitative recoveries by solid-phase extraction (mean recovery, 98 ?? 12%) at submicrogram-per-liter concentrations. An ammonium formate/formic acid buffer with a methanol/water gradient was used to separate the antimicrobials and to optimize the signal intensity. Mass spectral fragmentation and ionization characteristics were determined for each class of compounds for unequivocal identification. For all SAs, a characteristic m/z 156 ion representing the sulfanilyl fragment was identified. TCs exhibited neutral losses of 17 amu resulting from the loss of ammonia and 35 amu from the subsequent loss of water. Unusual matrix effects were seen only for TCs in this first survey of groundwater and surface water samples from sites around the United States, requiring that TCs be quantitated using the method of standard additions.

  16. Determination of ultra-trace amounts of prosthesis-related metals in whole blood using volumetric absorptive micro-sampling and tandem ICP - Mass spectrometry.

    Science.gov (United States)

    Bolea-Fernandez, Eduardo; Phan, Kim; Balcaen, Lieve; Resano, Martín; Vanhaecke, Frank

    2016-10-19

    This paper reports on an evaluation of the suitability of a novel sample collection approach, volumetric absorptive micro-sampling (VAMS), in the context of the determination of ultra-trace concentrations of prosthesis-related metals (Al, Ti, V, Co, Cr, Ni, Sr and Zr) in whole blood. In a first phase, a simple dilute-and-shoot approach (100-fold dilution) followed by tandem ICP - mass spectrometry (ICP-MS/MS) analysis was developed for the accurate and sensitive determination of the target elements. The ICP-MS/MS method relies on the use of mass shift reactions proceeding when pressurizing the collision/reaction cell (CRC) with CH 3 F/He for dealing with spectral overlap. Limits of detection (LoDs) between 0.3 and 30 ng L -1 were attained in a multi-element approach. The accuracy of the method was demonstrated via successful analysis of the reference materials Seronorm Whole Blood Levels 1 and 3, and real venous blood samples, spiked with the target elements at different concentration levels (5-50 μg L -1 ). Although the implementation of VAMS devices introduced contamination problems for Al, Cr and Ni, VAMS followed by ICP-MS/MS analysis shows potential for future real-life routine applications when assessing levels of Ti, V, Co, Sr and/or Zr. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. A dipole-assisted solid-phase extraction microchip combined with inductively coupled plasma-mass spectrometry for online determination of trace heavy metals in natural water.

    Science.gov (United States)

    Shih, Tsung-Ting; Hsu, I-Hsiang; Chen, Shun-Niang; Chen, Ping-Hung; Deng, Ming-Jay; Chen, Yu; Lin, Yang-Wei; Sun, Yuh-Chang

    2015-01-21

    We employed a polymeric material, poly(methyl methacrylate) (PMMA), for fabricating a microdevice and then implanted the chlorine (Cl)-containing solid-phase extraction (SPE) functionality into the PMMA chip to develop an innovative on-chip dipole-assisted SPE technique. Instead of the ion-ion interactions utilized in on-chip SPE techniques, the dipole-ion interactions between the highly electronegative C-Cl moieties in the channel interior and the positively charged metal ions were employed to facilitate the on-chip SPE procedures. Furthermore, to avoid labor-intensive manual manipulation, a programmable valve manifold was designed as an interface combining the dipole-assisted SPE microchip and inductively coupled plasma-mass spectrometry (ICP-MS) to achieve the fully automated operation. Under the optimized operation conditions for the established system, the detection limits for each analyte ion were obtained based on three times the standard deviation of seven measurements of the blank eluent solution. The limits ranged from 3.48 to 20.68 ng L(-1), suggesting that this technique appears uniquely suited for determining the levels of heavy metal ions in natural water. Indeed, a series of validation procedures demonstrated that the developed method could be satisfactorily applied to the determination of trace heavy metals in natural water. Remarkably, the developed device was durable enough to be reused more than 160 times without any loss in its analytical performance. To the best of our knowledge, this is the first study reporting on the combination of a dipole-assisted SPE microchip and elemental analysis instrument for the online determination of trace heavy metal ions.

  18. Coupling of an electrodialyzer with inductively coupled plasma mass spectrometry for the on-line determination of trace impurities in silicon wafers after surface metal extraction.

    Science.gov (United States)

    Chang, I-long; Hsu, I-hsiang; Yang, Mo-hsiung; Sun, Yun-chang

    2010-02-19

    Understanding the properties that determine the distribution and behavior of trace impurities in Si wafers is critical to defining and controlling the performance, reliability, and yields of integrated microelectronic devices. It remains, however, an intrinsically difficult task to determine trace impurities in Si because of the minute concentrations and extremely high levels of matrix involved. In this study, we used an electrodialyzer for the simultaneous on-line removal of the silicate and acid matrices through the neutralization of the excessive hydrogen ion and selectively separation of acid and silicate ions by the combination of electrode reaction as a source of hydroxide ions with the anion exchange membrane separation. To retain the analyte ions in the sample stream, we found that the presence of moderate amounts of nitric acid and hydrazine were necessary to improve the retention efficiency, not only for Zn(2+), Ni(2+), Cu(2+), and Co(2+) ions but also for CrO(4)(2-) ion. Under the optimized conditions, the interference that resulted from the sample matrix was suppressed significantly to provide satisfactory analytical signals. The precision of this method was ca. 5% when we used an electrodialyzer equipped with an anion exchange membrane to remove the sample matrix prior to performing inductively coupled plasma mass spectrometry (ICP-MS); the good agreement between the data obtained using our proposed method and those obtained using a batchwise wet chemical technique confirmed its accuracy. Our method permits the determination of Zn, Ni, Cu, Co, and Cr in Si wafers at detection limits within the range from 2.2 x 10(15) to 9.0 x 10(15) atoms cm(-3). Copyright 2009 Elsevier B.V. All rights reserved.

  19. Trace determination of 13 haloacetamides in drinking water using liquid chromatography triple quadrupole mass spectrometry with atmospheric pressure chemical ionization.

    Science.gov (United States)

    Chu, Wenhai; Gao, Naiyun; Yin, Daqiang; Krasner, Stuart W; Templeton, Michael R

    2012-04-27

    The haloacetamides (HAcAms) are disinfection by-products (DBPs) in drinking water which are currently receiving increased scientific attention due to their elevated toxicity relative to regulated disinfection by-products. A simultaneous determination method of 13 HAcAms, combining solid-phase extraction (SPE) enrichment, liquid chromatographic (LC) separation, and triple quadrupole mass spectrometry (tqMS) detection with atmospheric pressure chemical ionization (APCI) using selective reaction monitoring in positive mode, was developed to measure HAcAms, including chlorinated, brominated, and iodinated analogs. Ammonium chloride and Oasis HLB were selected as the dechlorinating reagent and polymeric SPE sorbent of HAcAm samples. The used tqMS apparatus showed higher sensitivity for the studied HAcAms in the APCI mode than electrospray ionization. 13 HAcAms were separated by LC in 9.0 min, and the detection limits ranged from 7.6 to 19.7 ng/L. The SPE-LC/tqMS method was successfully applied to quantify 13 HAcAms in drinking water samples for the first time, and first indentified tribromoacetamide and chloroiodoacetamide as DBPs in drinking water. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Gas chromatography-mass spectrometric determination of traces of ether-type icing inhibitors in free-floating fuels

    Energy Technology Data Exchange (ETDEWEB)

    Shin, H.S. [Dept. of Environmental Education, Kongju National Univ., Kongju (Korea); Abuse Drug Research Center, Kongju National Univ., Kongju (Korea); Ahn, H.S. [Dept. of Environmental Science, Kongju National Univ., Kongju (Korea)

    2004-08-01

    A gas chromatographic-mass spectrometric (GC-MS) assay method has been developed for simultaneous determination of ethylene glycol monomethyl ether (EGME) and diethylene glycol monomethly ether (DEGME) in spilled aviation fuels. Ethylene glycol monobutyl ether (EGBE) and ethylene glycol monoethyl ether (EGEE) were used as internal standard and surrogate, respectively. Sample preparation consisted of back-extraction with 7 mL dichloromethane after extraction of 50 mL of fuel with 2 mL of water. The extract was concentrated to dryness, dissolved in 100 {mu}L methanol, and analyzed by GC-MS with selected-ion monitoring (SIM). The peaks had good chromatographic properties on a semi-polar column. EGME and DEGME were extracted from fuel with high recovery of 75 and 85%, with small variations, respectively. Method detection limits were 1.3 and 1.0 ng mL{sup -1} for EGME and DEGME, respectively, in spilled fuel. DEGME was detected at concentrations of 22.6 and 19.7 ng mL{sup -1} in two samples from among five free-floating samples collected in a tunnel of a subway station located in the vicinity of an army base in Korea. The method might be useful for differentiation between the fuel-types kerosene and JP-8, which might originate from a storage tank. (orig.)

  1. Quantitative analysis of major and trace elements in NH4HF2-modified silicate rock powders by laser ablation - inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Zhang, Wen; Hu, Zhaochu; Liu, Yongsheng; Yang, Wenwu; Chen, Haihong; Hu, Shenghong; Xiao, Hongyan

    2017-08-29

    In this paper, we described a NH 4 HF 2 digestion method as sample preparation for the rapid determination of major and trace elements in silicate rocks using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Sample powders digested by NH 4 HF 2 at 230 °C for 3 h form ultrafine powders with a typical grain size d 80  rocks have a consistent grain morphology and size, allowing us to produce pressed powder pellets that have excellent cohesion and homogeneity suitable for laser ablation micro-analysis without the addition of binder. The influences of the digestion parameters were investigated and optimized, including the evaporation stage of removing residual NH 4 HF 2 , sample homogenization, selection of the digestion vessel and calibration strategy of quantitative analysis. The optimized NH 4 HF 2 digestion method was applied to dissolve six silicate rock reference materials (BCR-2, BHVO-2, AGV-2, RGM-2, GSP-2, GSR-1) covering a wide range of rock types. Ten major elements and thirty-five trace elements were simultaneously analyzed by LA-ICP-MS. The analytical results of the six reference materials generally agreed with the recommended values, with discrepancies of less than 10% for most elements. The analytical precision is within 5% for most major elements and within 10% for most trace elements. Compared with previous methods of LA-ICP-MS bulk analysis, our method enables the complete dissolution of refractory minerals, such as zircon, in intermediate-acidic intrusive rocks and limits contamination as well as the loss of volatile elements. Moreover, there are many advantages for the new technique, including reducing matrix effects between reference materials and samples, spiking the internal standard simply and feasibly and sample batch processing. The applicability filed of the new technique in this study was focused on the whole-rock analysis of igneous rock samples, which are from basic rocks to acid rocks (45% rock analysis

  2. Depth profiles of H, C, O, Al and Si implants in a GaN substrate using trace element accelerator mass spectrometry

    Science.gov (United States)

    Mitchell, Lee J.; Ravi Prasad, G. V.; Pelicon, Primoz; Smith, Eric B.; McDaniel, Floyd D.

    2004-06-01

    The compound semiconductor GaN has become the electronic material for many semiconductor applications because of its high-power, high-temperature and high-frequency characteristics. The introduction of impurities to GaN, either by direct doping or by contamination of unwanted impurities during fabrication leads to changes in its electronic properties [CAARI 2002: 17th International Conference on the Application of Accelerators in Research and Industry, American Institute of Physics, Vol. 680, 2002, p. 369]. There are a number of techniques routinely used to analyze the depth profiles of impurities in semiconductor substrates, but they lack the sensitivity required for today's applications. For example, secondary ion mass spectrometry (SIMS) has molecular interferences which obscure analysis of some elements. Trace element accelerator mass spectrometry (TEAMS), which is a combination of accelerator mass spectrometry (AMS) and SIMS, removes molecular interferences by breaking apart the molecules in an accelerator. Like SIMS, secondary ions are sputtered from a target, the negative ions are then extracted and injected into a 3 MV tandem accelerator. As they pass through a gas at the center of the terminal, molecular breakup is achieved via a coulomb explosion due to electron stripping. The ions are then passed through momentum/charge and energy/charge filters, which are used to separate out many of the unwanted interferences. In most cases, TEAMS is a complimentary technique to SIMS and can eliminate the interferences that may not be resolvable by SIMS. The purpose of this work is to examine the depth profiles and detection limits of various impurities implanted into a GaN substrate.

  3. Trace analysis of isothiazolinones in water samples by large-volume direct injection liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Speksnijder, P; van Ravestijn, J; de Voogt, P

    2010-08-06

    Isothiazolinones are used as preservatives, biocides and disinfectants in a variety of industrial and domestic applications. Some of the isothiazolinones are difficult to isolate from water due their high polarity. A sensitive and selective analytical method was developed and optimized for the determination of sub-microg/L levels of three isothiazolinones in water samples. Three isothiazolinones are described in this paper: 2-methyl-3-isothiazolinone, 5-chloro-2-methyl-3-isothiazolinone and 4,5-dichloro-2-methyl-3-isothiazolinone. The analytical method involves a robust large-volume direct on-column loop injection of 2 mL on an Aqua ODS HPLC column and tandem MS detection (HPLC-MS/MS). After filtration, samples are directly injected without further pretreatment. Detection limits of the individual target compounds were between 0.03 and 0.1 microg/L employing Multi-Reaction Monitoring (MRM) mass spectrometry. Based on the constant ratio of two selected product-ions together with the retention time, the identification is very selective and quantification is reliable. The method was successfully applied to real samples of membrane flushings, drinking water, surface waters and waste water. Additional investigations showed the instability of the isothiazolinones in river- and waste water. Preservation of river water and waste water samples with sodium azide (NaN(3)) promotes the stability of the isothiazolines in solution. In membrane flushings, waste water, surface waters and drinking water, levels of the three isothiazolinones were all below the limit of detection. In effluents of households containing washings from normal shampoo use, isothiazolinones could be detected. Copyright 2010 Elsevier B.V. All rights reserved.

  4. Tracing the Mass-Dependent Star Formation History of Late-Type Galaxies using X-ray Emission: Results from the CHANDRA Deep Fields

    Science.gov (United States)

    Lehmer, B.D; Brandt, W.N.; Schneider, D.P.; Steffen, A.T.; Alexander, D.M.; Bell, E.F.; Hornschemeier, A.E.; McIntosh, D.H.; Bauer, F.E.; Gilli, R.; hide

    2008-01-01

    We report on the X-ray evolution over the last approx.9 Gyr of cosmic history (i.e., since z = 1.4) of late-type galaxy populations in the Chandra Deep Field-North and Extended Chandra Deep Field-South (CDF-N and E-CDF-S. respectively; jointly CDFs) survey fields. Our late-type galaxy sample consists of 2568 galaxies. which were identified using rest-frame optical colors and HST morphologies. We utilized X-ray stacking analyses to investigate the X-ray emission from these galaxies, emphasizing the contributions from normal galaxies that are not dominated by active galactic nuclei (AGNs). Over this redshift range, we find significant increases (factors of approx. 5-10) in the X-ray-to-optical mean luminosity ratio (L(sub x)/L(sub B)) and the X-ray-to-stellar-mass mean ratio (L(sub x)/M(sub *)) for galaxy populations selected by L(sub B) and M(sub *), respectively. When analyzing galaxy samples selected via SFR, we find that the mean X-ray-to-SFR ratio (L(sub x)/SFR) is consistent with being constant over the entire redshift range for galaxies with SFR = 1-100 Solar Mass/yr, thus demonstrating that X-ray emission can be used as a robust indicator of star-formation activity out to z approx. 1.4. We find that the star-formation activity (as traced by X-ray luminosity) per unit stellar mass in a given redshift bin increases with decreasing stellar mass over the redshift range z = 0.2-1, which is consistent with previous studies of how star-formation activity depends on stellar mass. Finally, we extend our X-ray analyses to Lyman break galaxies at z approx. 3 and estimate that L(sub x)/L(sub B) at z approx. 3 is similar to its value at z = 1.4.

  5. Selective and trace determination of monochloramine in river water by chemical derivatization and liquid chromatography/tandem mass spectrometry analysis.

    Science.gov (United States)

    Kinani, Said; Layousse, Stéphany; Richard, Bertille; Kinani, Aziz; Bouchonnet, Stéphane; Thoma, Astrid; Sacher, Frank

    2015-08-01

    Monochloramine (MCA) may enter the aquatic environment through three main sources: wastewater treatment plant effluents, industrial effluents and thermal power plant wastes. Up to date, there are no available data about the concentration levels of this chemical in river water due to lack of appropriate analytical methods. Therefore, sensitive and selective analytical methods for monochloramine analysis in river water are required to evaluate its environmental fate and its effects on aquatic ecosystems. Thus, in this study we describe a highly specific and sensitive method for monochloramine determination in river water. This method combines chemical derivatization of monochloramine into indophenol followed by liquid chromatography coupled to electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS) analysis. Two precursor-to-product ion transitions were monitored (200→127 and 200→154) in positive ionisation mode, fulfilling the criteria of selectivity, in accordance with the European Legislation requirements (decision 2002/657/EC). Ion structures and fragmentation mechanisms have been proposed to explain the selected transitions. Linearity range, accuracy and precision of the method have been assessed according to the French method validation standard NF T90-210. Detecting the derivatized monochloramine (indophenol) in Multiple Reaction Monitoring (MRM) mode provided a limit of quantification of 40 ng L(-1) equivalent monochloramine. Applied to Loire river water (France), the developed method occasionally detected monochloramine at concentrations less than 300 ng L(-1), which could be explained by punctual discharges of water containing active chlorine upstream of the sampling point. Indeed, it is widely reported in the literature that the addition of chlorine to water containing ammonia (e.g., wastewater effluents and river water) may result in the instantaneous formation of monochloramine. The proposed method is a powerful tool that can be used in

  6. Experimental design for the optimization and robustness testing of a liquid chromatography tandem mass spectrometry method for the trace analysis of the potentially genotoxic 1,3-diisopropylurea.

    Science.gov (United States)

    Székely, György; Henriques, Bruno; Gil, Marco; Alvarez, Carlos

    2014-09-01

    This paper discusses a design of experiments (DoE) assisted optimization and robustness testing of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method development for the trace analysis of the potentially genotoxic 1,3-diisopropylurea (IPU) impurity in mometasone furoate glucocorticosteroid. Compared to the conventional trial-and-error method development, DoE is a cost-effective and systematic approach to system optimization by which the effects of multiple parameters and parameter interactions on a given response are considered. The LC and MS factors were studied simultaneously: flow (F), gradient (G), injection volume (Vinj), cone voltage (E(con)), and collision energy (E(col)). The optimization was carried out with respect to four responses: separation of peaks (Sep), peak area (A(p)), length of the analysis (T), and the signal-to-noise ratio (S/N). An optimization central composite face (CCF) DoE was conducted leading to the early discovery of carry-over effect which was further investigated in order to establish the maximum injectable sample load. A second DoE was conducted in order to obtain the optimal LC-MS/MS method. As part of the validation of the obtained method, its robustness was determined by conducting a fractional factorial of resolution III DoE, wherein column temperature and quadrupole resolution were considered as additional factors. The method utilizes a common Phenomenex Gemini NX C-18 HPLC analytical column with electrospray ionization and a triple quadrupole mass detector in multiple reaction monitoring (MRM) mode, resulting in short analyses with a 10-min runtime. The high sensitivity and low limit of quantification (LOQ) was achieved by (1) MRM mode (instead of single ion monitoring) and (2) avoiding the drawbacks of derivatization (incomplete reaction and time-consuming sample preparation). Quantitatively, the DoE method development strategy resulted in the robust trace analysis of IPU at 1.25 ng/mL absolute concentration

  7. Trace analysis of chlorophenols in river water samples by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, M.; Ishii, Y.; Okanouchi, N.; Sakui, N.; Ito, R.; Inoue, K.; Nakazawa, H. [Hoshi Univ., Tokyo (Japan). Dept. of Analytical Chemistry, Faculty of Pharmaceutical Sciences; Saito, K. [Saitama Institute of Public Health, Saitama (Japan). Dioxin Research Group

    2004-09-15

    Many analytical methods for the determination of chlorophenols in water samples have been reported including gas chromatography-mass spectrometry (GC-MS). However, GC-MS was initially used for the determination of phenol compounds even though derivatization was required. The derivatization leads to sharper peaks and hence to better separation and higher sensitivity for the phenols. However, the derivatization faces the risk of contamination and hence an overestimation of chlorophenols concentration. In order to overcome these problems, in situ derivatization has been developed, which involves the simple addition of a reagent to a liquid sample. Recently, a new sorptive extraction technique that uses a stir bar coated with polydimethylsiloxane (PDMS) was developed. The technique is known as stir bar sorptive extraction (SBSE). We already reported that determination of 4-tert-octylphenol (OP) and 4-nonylphenol (NP) in river water4 and body fluid samples by using SBSE. In addition, SBSE with in situ derivatization has been successfully used in the determination of bisphenol A (BPA) in human body fluid samples6 and phenolic xenoestrogens in river water samples. The aim of this study is to determine trace amounts of chlorophenols in water samples by SBSE with in situ derivatization, followed by thermal desorption (TD)-GC-MS. The developed method was applied to determination of chlorophenols in river water samples.

  8. Determination of polybrominated diphenyl ethers at trace levels in environmental waters using hollow-fiber microporous membrane liquid-liquid extraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Fontanals, Núria; Barri, Thaer; Bergström, Staffan; Jönsson, Jan-Ake

    2006-11-10

    In this study, we present a simple and easy-to-use extraction method that is based on a hollow-fiber microporous membrane liquid-liquid extraction (HF-MMLLE), as an extraction technique, followed by gas chromatography-mass spectrometry (GC-MS) to determine a group of brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), at trace levels in aqueous samples. The hollow-fiber membrane (HF) filled with organic solvent was immersed into the aqueous sample, spiked with the analytes at ng l(-1) level, and stirred for 60 min. The proposed method could attain enrichment factors (E(e)) up to 5200 times, after optimising parameters, such as organic solvent, stirring speed and extraction time, that affect the extraction. The HF-MMLLE-GC-MS method was successfully applied to the extraction of PBDEs from tap, river and leachate water samples with spike recoveries ranging from 85% to 110%. The method validation with reagent and leachate water samples provided good linearity, detection limits of 1.1 ng l(-1) or lower, both in reagent and leachate water, as well as satisfactory precision in terms of repeatability and reproducibility with values of % relative standard deviation (%RSD) lower than 8.6 and 16.9, respectively.

  9. Comparison of the Detection Characteristics of Trace Species Using Laser-Induced Breakdown Spectroscopy and Laser Breakdown Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Zhenzhen Wang

    2015-03-01

    Full Text Available The rapid and precise element measurement of trace species, such as mercury, iodine, strontium, cesium, etc. is imperative for various applications, especially for industrial needs. The elements mercury and iodine were measured by two detection methods for comparison of the corresponding detection features. A laser beam was focused to induce plasma. Emission and ion signals were detected using laser-induced breakdown spectroscopy (LIBS and laser breakdown time-of-flight mass spectrometry (LB-TOFMS. Multi-photon ionization and electron impact ionization in the plasma generation process can be controlled by the pressure and pulse width. The effect of electron impact ionization on continuum emission, coexisting molecular and atomic emissions became weakened in low pressure condition. When the pressure was less than 1 Pa, the plasma was induced by laser dissociation and multi-photon ionization in LB-TOFMS. According to the experimental results, the detection limits of mercury and iodine in N2 were 3.5 ppb and 60 ppb using low pressure LIBS. The mercury and iodine detection limits using LB-TOFMS were 1.2 ppb and 9.0 ppb, which were enhanced due to different detection features. The detection systems of LIBS and LB-TOFMS can be selected depending on the condition of each application.

  10. Trace analysis of trimethoprim and sulfonamide, macrolide, quinolone, and tetracycline antibiotics in chlorinated drinking water using liquid chromatography electrospray tandem mass spectrometry

    Science.gov (United States)

    Ye, Z.; Weinberg, H.S.; Meyer, M.T.

    2007-01-01

    A multirun analytical method has been developed and validated for trace determination of 24 antibiotics including 7 sulfonamides, 3 macrolides, 7 quinolones, 6 tetracyclines, and trimethoprim in chlorine-disinfected drinking water using a single solid-phase extraction method coupled to liquid chromatography with positive electrospray tandem mass spectrometry detection. The analytes were extracted by a hydrophilic-lipophilic balanced resin and eluted with acidified methanol (0.1% formic acid), resulting in analyte recoveries generally above 90%. The limits of quantitation were mostly below 10 ng/L in drinking water. Since the concentrated sample matrix typically caused ion suppression during electrospray ionization, the method of standard addition was used for quantitation. Chlorine residuals in drinking water can react with some antibiotics, but ascorbic acid was found to be an effective chlorine quenching agent without affecting the analysis and stability of the antibiotics in water. A preliminary occurrence study using this method revealed the presence of some antibiotics in drinking waters, including sulfamethoxazole (3.0-3.4 ng/L), macrolides (1.4-4.9 ng/L), and quinolones (1.2-4.0 ng/L). ?? 2007 American Chemical Society.

  11. Trace-level determination of polar flavour compounds in butter by solid-phase extraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Adahchour, M; Vreuls, R J; van der Heijden, A; Brinkman, U A

    1999-06-04

    Volatile compounds are responsible for the aromas of butter. A simple technique for the determination of these components is described which is based on solid-phase extraction (SPE) after melting of the butter and separation of the aqueous phase from the fat. Volatile flavours present in the water fraction are collected by off-line SPE on cartidges packed with a copolymer sorbent. After desorption with 500 microliters of methyl acetate, 1-microliter aliquots are quantified and/or identified by gas chromatography-mass spectrometry. The procedure was tested with respect to recovery, linearity and limit of detection in real-life samples using five polar model analytes. It allows the characterisation of polar flavour compounds in butter prior to and after heat treatment at 170 degrees C. From the five model compounds, vanillin, traces of diacetyl and maltol were found to be present in the butter samples. After heat treatment 500-1000-fold increased concentration of maltol, and substantial amounts of furaneol were detected.

  12. Enantioselective column coupled electrophoresis employing large bore capillaries hyphenated with tandem mass spectrometry for ultra-trace determination of chiral compounds in complex real samples.

    Science.gov (United States)

    Piešťanský, Juraj; Maráková, Katarína; Kovaľ, Marián; Havránek, Emil; Mikuš, Peter

    2015-12-01

    A new multidimensional analytical approach for the ultra-trace determination of target chiral compounds in unpretreated complex real samples was developed in this work. The proposed analytical system provided high orthogonality due to on-line combination of three different methods (separation mechanisms), i.e. (1) isotachophoresis (ITP), (2) chiral capillary zone electrophoresis (chiral CZE), and (3) triple quadrupole mass spectrometry (QqQ MS). The ITP step, performed in a large bore capillary (800 μm), was utilized for the effective sample pretreatment (preconcentration and matrix clean-up) in a large injection volume (1-10 μL) enabling to obtain as low as ca. 80 pg/mL limits of detection for the target enantiomers in urine matrices. In the chiral CZE step, the different chiral selectors (neutral, ionizable, and permanently charged cyclodextrins) and buffer systems were tested in terms of enantioselectivity and influence on the MS detection response. The performance parameters of the optimized ITP - chiral CZE-QqQ MS method were evaluated according to the FDA guidance for bioanalytical method validation. Successful validation and application (enantioselective monitoring of renally eliminated pheniramine and its metabolite in human urine) highlighted great potential of this chiral approach in advanced enantioselective biomedical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Detection and quantitation of trace phenolphthalein (in pharmaceutical preparations and in forensic exhibits) by liquid chromatography-tandem mass spectrometry, a sensitive and accurate method.

    Science.gov (United States)

    Sharma, Kakali; Sharma, Shiba P; Lahiri, Sujit C

    2013-01-01

    Phenolphthalein, an acid-base indicator and laxative, is important as a constituent of widely used weight-reducing multicomponent food formulations. Phenolphthalein is an useful reagent in forensic science for the identification of blood stains of suspected victims and for apprehending erring officials accepting bribes in graft or trap cases. The pink-colored alkaline hand washes originating from the phenolphthalein-smeared notes can easily be determined spectrophotometrically. But in many cases, colored solution turns colorless with time, which renders the genuineness of bribe cases doubtful to the judiciary. No method is known till now for the detection and identification of phenolphthalein in colorless forensic exhibits with positive proof. Liquid chromatography-tandem mass spectrometry had been found to be most sensitive, accurate method capable of detection and quantitation of trace phenolphthalein in commercial formulations and colorless forensic exhibits with positive proof. The detection limit of phenolphthalein was found to be 1.66 pg/L or ng/mL, and the calibration curve shows good linearity (r(2) = 0.9974). © 2012 American Academy of Forensic Sciences.

  14. Bulk derivatization and cation exchange restricted access media-based trap-and-elute liquid chromatography–mass spectrometry method for determination of trace estrogens in serum

    Energy Technology Data Exchange (ETDEWEB)

    Beinhauer, Jana [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Bian, Liangqiao [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Fan, Hui [Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX (United States); Šebela, Marek [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Kukula, Maciej [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Barrera, Jose A. [Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); and others

    2015-02-09

    Highlights: • Analysis of estrogens in small volume samples at low parts-per-trillion concentration. • Charged bulk derivatization facilitates on-line ion exchange sample preparation. • On-line WCX restricted access media traps analytes, but not proteins and lipids. • Complete preparation and LC–MS/MS analysis completed in 30 min/sample. - Abstract: Estrone (E1), estradiols (α/β-E2), and estriol (E3) are four major metabolically active estrogens exerting strong biological activities at very low circulating concentrations. This paper reports a sensitive and efficient method with automated, on-line clean-up and detection to determine trace estrogens in a small volume of serum samples using liquid chromatography–electrospray ionization–tandem mass spectrometry directly, without off-line liquid–liquid or solid-phase extraction pretreatments. Serum aliquots (charcoal stripped fetal bovine serum, 100 μL) were spiked with four estrogen standards and their corresponding isotope-labeled internal standards, then bulk derivatized with 2-fluoro-1-methyl-pyridium p-toluenesulfonate (2-FMP) to establish the calibration curves and perform method validation. Calibration was established in the concentration ranges of 5–1000 pg mL{sup −1}, and demonstrated good linearity of R{sup 2} from 0.9944 to 0.9997 for the four derivatized estrogens. The lower detection limits obtained were 3–7 pg mL{sup −1}. Good accuracy and precision in the range of 86–112% and 2.3–11.9%, respectively, were observed for the quality control (QC) samples at low, medium, and high concentration levels. The stability tests showed that the derivatized serum samples were stable 8 h after derivatization at room temperature and at least to 48 h if stored at −20 °C. The method was applied to measure trace estrogens in real human and bovine serum samples, and three of four estrogen compounds studied were observed and quantified.

  15. Restricted accessed nanoparticles for direct magnetic solid phase extraction of trace metal ions from human fluids followed by inductively coupled plasma mass spectrometry detection.

    Science.gov (United States)

    Yan, Ping; He, Man; Chen, Beibei; Hu, Bin

    2015-06-21

    Herein, restricted accessed magnetic nanoparticles were synthesized by self-assembly of a non-ionic surfactant (Tween-20) onto the 4-(2-pyridylazo)resorcinol (PAR) functionalized magnetic nanoparticles (MNPs). A series of analytical techniques were employed for the characterization of the as-prepared restricted accessed Fe3O4@SiO2@PAR, and it was found that the as-prepared restricted accessed Fe3O4@SiO2@PAR nanoparticles have a porous structure with a BET surface area of around 99.4 m(2) g(-1), an average pore size of about 6.14 nm and a pore volume of 0.47 cm(3) g(-1). Besides, the prepared restricted accessed Fe3O4@SiO2@PAR showed good size exclusion properties toward proteins, providing application potential for the direct analysis of biological samples. Based on this, a novel method of restricted accessed magnetic solid phase extraction (MSPE) combined with inductively coupled plasma-mass spectrometry (ICP-MS) was developed for the direct determination of trace metal ions in human fluids. The parameters affecting the extraction of the target metals by MSPE were studied and the optimized conditions were established. Under the optimum conditions, the adsorption capacity of Cr(III), Cd(II), La(III), Nd(III) and Pb(II) on the as-prepared restricted accessed Fe3O4@SiO2@PAR was 62.9, 56.6, 33.7, 36.9 and 43.3 mg g(-1), respectively. With an enrichment factor of 30, the limits of detection for Cr(III), Cd(II), La(III), Nd(III) and Pb(II) were as low as 11.9, 0.8, 0.7, 1.6 and 4.1 ng L(-1), and the relative standard deviations were 7.6, 8.7, 8.4, 8.1 and 5.0 (C(Cr, Pb) = 0.05 μg L(-1), C(Cd, La) = 0.005 μg L(-1), C(Nd) = 0.01 μg L(-1), n = 7), respectively. The developed method was successfully applied for the direct analysis of free metal ions in human urine and serum samples, and has the advantages of good anti-interference ability, high sensitivity and exhibits great application potential in the direct analysis of trace metals in biological fluids.

  16. Trace analysis of fluoxetine and its metabolite norfluoxetine. Part I: development of a chiral liquid chromatography-tandem mass spectrometry method for wastewater samples.

    Science.gov (United States)

    Barclay, Victoria K H; Tyrefors, Niklas L; Johansson, I Monika; Pettersson, Curt E

    2011-08-19

    An enantioselective method for the determination of fluoxetine (a selective serotonin reuptake inhibitor) and its pharmacologically active metabolite norfluoxetine has been developed for raw and treated wastewater samples. The stable isotope-labeled fluoxetine and norfluoxetine were used in an extended way for extraction recovery calculations at trace level concentrations in wastewater. Wastewater samples were enriched by solid phase extraction (SPE) with Evolute CX-50 extraction cartridges. The obtained extraction recoveries ranged between 65 and 82% in raw and treated wastewater at a trace level concentration of 50 pM (15-16 ng L⁻¹). The target compounds were identified by the use of chiral liquid chromatography tandem mass spectrometry (LC-MS/MS) in selected reaction monitoring (SRM) mode. The enantiomers were successfully resolved on a chiral α₁-acid glycoprotein column (chiral AGP) with acetonitrile and 10 mM ammonium acetate buffer at pH 4.4 (3/97, v/v) as the mobile phase. The effects of pH, amount of organic modifier and buffer concentration in the mobile phase were investigated on the enantiomeric resolution (R(s)) of the target compounds. Enantiomeric R(s)-values above 2.0 (1.03 RSD%, n=3) were achieved for the enantiomers of fluoxetine and norfluoxetine in all mobile phases investigated. The method was validated by assessing parameters such as cross-contamination and carryover during SPE and during LC analysis. Cross-talk effects were examined during the detection of the analytes in SRM mode. In addition, the isotopic purity of fluoxetine-d₅ and norfluoxetine-d₅ were assessed to exclude the possibility of self-contamination. The interassay precision of the chromatographic separation was excellent, with relative standard deviations (RSD) equal to or lower than 0.56 and 0.81% in raw and treated wastewaters, respectively. The method detection and quantification limits (respectively, MDL and MQL) were determined by the use of fluoxetine-d₅ and

  17. Trace determination of β-blockers and β2-agonists in distilled and waste-waters using liquid chromatography-tandem mass spectrometry and solid-phase extraction.

    Science.gov (United States)

    Salem, Alaa A; Wasfi, Ibrahim A; Al-Nassibi, Salama S

    2012-11-01

    A highly sensitive method for simultaneous determinations of eleven β-blockers and β-agonists in distilled and waste-waters using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS) was developed, optimized and validated. The method was used for trace determinations of acebutolol, atenolol, metoprolol, propranolol, timolol, nadolol, labetalol, oxprenolol, pindolol, alprenolol and terbutaline. Oasis MCX and Clean Screen cartridges were used for solid phase extractions and an alkaline mixture of dichloromethane-propanol was used as mobile phase. Matrix effect was reduced by using methanol as a pre-eluant for removing co-extractives on the SPE cartridges and by applying the internal standard method for quantification. Using Oasis MCX-SPE cartridges, developed method gave average recoveries of 77.20-97.30% for drugs spiked at 150.00-500.00pg/ml. Intra-day precisions gave RSD of 3.367-12.489% while as inter-day precisions gave RSD of 6.425-19.768%. Detection limits of 0.11-6.74pg/ml and quantification limits of 0.14-22.88pg/ml were obtained. Signal's suppression in the range of 4.50-24.50% was recorded due to the matrix effect. Drugs spiked in wastewater at 500.00pg/ml concentrations level and stored at 4°C for 6 days, showed insignificant degradation. Developed method was successfully applied to the analysis of pharmaceutical residues in effluents wastewaters. Five β-blockers and one β-agonists were detected in Al-Ain and Abu Dhabi wastewaters at average concentrations of 3.44-19.05pg/ml. Atenolol was detected at higher average concentration ranged in 125.60-234.28pg/ml. Results obtained suggest that adopted wastewater treatment processes are not enough to degrade these compounds. Copyright © 2012. Published by Elsevier B.V.

  18. Enhancement of sensitivity in the determination of organic trace compounds in complex matrices with liquid chromatography-mass spectrometry (LC-MS)

    International Nuclear Information System (INIS)

    Mascher, D.G.

    2002-05-01

    The PhD-thesis deals with 'enhancement of sensitivity in the determination of organic trace compounds in complex matrices with liquid chromatography-mass spectrometry (LC-MS)'. Almost the most important factor is the enhancement of the ionization yield with Atmospheric Pressure Chemical Ionization (APCI) or Electrospray Ionization (ESI) in LC-MS. Ionization yields of different compounds can vary by a factor of 10000. Three ways to solve this problem of little ionization yield were tried: 1) Modification of the mobile phase in HPLC 2) Chemical modification of the analytes 3) A new type of ionization called Atmospheric Pressure Photo Ionization (APPI). ad 1) By using specific additives to mobile phases ion suppression that might derive from an ion pair reagent that was necessary for chromatography could be omitted. General remarks cannot be done. ad 2) Chemical modification or so called derivatization is well known for UV- and fluorescence-detection for a long period of time. As substances containing nitrogene (e.g. primary, secondary or tertiary amines) often have good ionization yields, poor or relatively poor ionizable substances like carboxylic acids, sugars and partially phenolic steroids were used as analytes for derivatization reactions. By using Dansyl as Dansylchlorid or Dansylhydrazine a basic derivatization agent could be found that ionizes very well. A 200 times more sensitive determination of estrogenes is possible after derivatization with Dansylchlorid. Using a tandem-mass-spectrometer a lower limit of quantification of 2 pg/mL plasma could be reached by using 1 mL of plasma. For ketones like carvon and campher an enhancement by a factor of 500 and 4000 could be reached by using Dansylhydrazine as the derivatization agent. For fatty acids DMEQ as derivatization agent enhanced the sensitivity by a factor of 20 to 100. ad 3) APPI as a new ionization mode showed really good results for specific molecules. Relatively unpolar substances as diphenylsulfide

  19. Analytical evaluation of nebulizers for the introduction of acetic acid extracts aiming at the determination of trace elements by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gois, Jefferson S. de; Maranhao, Tatiane de A. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil); Oliveira, Fernando J.S. [Petroleo Brasileiro S.A., Gerencia de Meio Ambiente, Rio de Janeiro, RJ (Brazil); Frescura, Vera L.A.; Curtius, Adilson J. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil); Borges, Daniel L.G., E-mail: daniel.borges@ufsc.br [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil)

    2012-11-15

    Most of the official procedures aiming at classification of solid waste toxicity take into account metal solubility and bioavailability by means of extraction experiments using acetic acid solutions. Hence, the aim of this work was to investigate and optimize conditions to suppress the effect of acetic acid on the determination of trace elements using inductively coupled plasma mass spectrometry. The performance of four nebulizers (cross-flow (CFN), ultrasonic (USN), Meinhard (MN) and MicroMist (MMN)) were compared as to their efficiency in minimizing spectral and non-spectral effects on the determination of Ag, As, Ba, Cd, Cr, Hg, Pb and Se, with the ultimate goal to analyze acetic acid extracts obtained from solid waste residues. Operating conditions (desolvation temperatures for USN, RF power and nebulizer gas flow rates) were optimized individually for each nebulizer and for all analytes maintained in 0.14 mol L{sup -1} HNO{sub 3} solutions and in solutions prepared with acetic acid and acetic acid + NaOH, adjusted to pH 2.88 and 4.93, respectively. Pronounced non-spectral interferences for {sup 75}As and {sup 82}Se were observed in the presence of acetic acid for CF and MN, although to a less extent also for MMN and USN. Signal increase for blank solutions measured at m/z 208 ({sup 208}Pb) for CFN and MN, 107 ({sup 107}Ag) for USN and MN coupled to a cyclonic chamber and, m/z 82 ({sup 82}Se) for USN was observed, indicating an increased risk of spectral interference upon an increase in the concentration of acetic acid. Signal increase at specific m/z ratios, however, was not significant when the MMN was used, with the exception of m/z 52 ({sup 52}Cr) in acetic acid solutions, arising from the formation of {sup 40}Ar{sup 12}C{sup +}. This same effect was noticed for all nebulizers, although at noticeably different intensities. A signal stability study was performed, demonstrating that variations in the analytical signal were within a 20% range for all analytes

  20. A Comparative Study of Selected Trace Element Content in Malay and Chinese Traditional Herbal Medicine (THM Using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS

    Directory of Open Access Journals (Sweden)

    Sharifah Mohamad

    2013-02-01

    Full Text Available A total of 60 products of traditional herbal medicine (THM in various dosage forms of herbal preparation were analyzed to determine selected trace elements (i.e., Zn, Mn, Cu, Cd, and Se using ICP-MS. Thirty types of both Chinese and Malay THMs were chosen to represent each population. The closed vessel acid microwave digestion method, using CEM MARS 5, was employed for the extraction of the selected trace elements. The digestion method applied was validated by using certified reference material from the Trace Element in Spinach Leaves (SRM1570a. The recoveries of all elements were found to be in the range of 85.3%–98.9%. The results indicated that Zn, Mn, Cu, Cd and Se have their own trends of concentrations in all samples studied. The daily intake concentrations of the elements were in the following order: Mn > Zn > Cu > Se > Cd. Concentrations of all five elements were found to be dominant in Chinese THMs. The essentiality of the selected trace elements was also assessed, based on the recommended daily allowance (RDA, adequate intake (AI and the United States Pharmacopeia (USP for trace elements as reference. The concentrations of all elements studied were below the RDA, AI and USP values, which fall within the essential concentration range, except for cadmium.

  1. Multielement determination of trace elements in seawater by inductively coupled plasma mass spectrometry after tandem preconcentration with cooperation of chelating resin adsorption and lanthanum coprecipitation

    International Nuclear Information System (INIS)

    Yabutani, Tomoki; Chiba, Koichi; Haraguchi, Hiroki

    2001-01-01

    A tandem preconcentration method, in which chelating resin adsorption and La coprecipitation were cooperatively employed for preconcentration, was developed as a pretreatment method for simultaneous multielement determination of trace elements in seawater by ICP-MS. First, the seawater sample (250 ml) was treated with a chelating resin for preconcentration of trace elements, and then trace elements with good recoveries were determined by ICP-MS. Trace elements with the chemical properties of oxoanion- and hydride-formation, which were poorly recovered in the chelating resin preconcentration, were further subjected to preconcentration by La coprecipitation. As a result, more than 30 elements could be determined in the concentration range from 9.6 μg L -1 for Mo to 0.00018 μg L -1 for Tm, when the present tandem method was applied to the analysis of open seawater standard reference material (NASS-4). Furthermore, the analytical results for open seawater reference materials were compared with those for coastal seawater reference material as well as for coastal seawater collected in the Ise Bay. It was found that the multielement data for trace elements in these seawater samples clearly showed different elemental distributions, reflecting the different marine environments. (author)

  2. TRACING EMBEDDED STELLAR POPULATIONS IN CLUSTERS AND GALAXIES USING MOLECULAR EMISSION: METHANOL AS A SIGNATURE OF THE LOW-MASS END OF THE IMF

    International Nuclear Information System (INIS)

    Kristensen, Lars E.; Bergin, Edwin A.

    2015-01-01

    Most low-mass protostars form in clusters, in particular high-mass clusters; however, how low-mass stars form in high-mass clusters and what the mass distribution is are still open questions both in our own Galaxy and elsewhere. To access the population of forming embedded low-mass protostars observationally, we propose using molecular outflows as tracers. Because the outflow emission scales with mass, the effective contrast between low-mass protostars and their high-mass cousins is greatly lowered. In particular, maps of methanol emission at 338.4 GHz (J = 7 0 –6 0 A + ) in low-mass clusters illustrate that this transition is an excellent probe of the low-mass population. We present here a model of a forming cluster where methanol emission is assigned to every embedded low-mass protostar. The resulting model image of methanol emission is compared to recent ALMA observations toward a high-mass cluster and the similarity is striking: the toy model reproduces observations to better than a factor of two and suggests that approximately 50% of the total flux originates in low-mass outflows. Future fine-tuning of the model will eventually make it a tool for interpreting the embedded low-mass population of distant regions within our own Galaxy and ultimately higher-redshift starburst galaxies, not just for methanol emission but also water and high-J CO

  3. TRACING EMBEDDED STELLAR POPULATIONS IN CLUSTERS AND GALAXIES USING MOLECULAR EMISSION: METHANOL AS A SIGNATURE OF THE LOW-MASS END OF THE IMF

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, Lars E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bergin, Edwin A., E-mail: lkristensen@cfa.harvard.edu [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)

    2015-07-10

    Most low-mass protostars form in clusters, in particular high-mass clusters; however, how low-mass stars form in high-mass clusters and what the mass distribution is are still open questions both in our own Galaxy and elsewhere. To access the population of forming embedded low-mass protostars observationally, we propose using molecular outflows as tracers. Because the outflow emission scales with mass, the effective contrast between low-mass protostars and their high-mass cousins is greatly lowered. In particular, maps of methanol emission at 338.4 GHz (J = 7{sub 0}–6{sub 0} A{sup +}) in low-mass clusters illustrate that this transition is an excellent probe of the low-mass population. We present here a model of a forming cluster where methanol emission is assigned to every embedded low-mass protostar. The resulting model image of methanol emission is compared to recent ALMA observations toward a high-mass cluster and the similarity is striking: the toy model reproduces observations to better than a factor of two and suggests that approximately 50% of the total flux originates in low-mass outflows. Future fine-tuning of the model will eventually make it a tool for interpreting the embedded low-mass population of distant regions within our own Galaxy and ultimately higher-redshift starburst galaxies, not just for methanol emission but also water and high-J CO.

  4. The coupling of capillary electrophoresis-inductively coupled plasma mass spectrometer as a speciation instrument for actinides at trace level; Le couplage electrophorese capillaire-spectrometre de masse a source plasma en tant qu'instrument de speciation des actinides a l'etat de traces

    Energy Technology Data Exchange (ETDEWEB)

    Delorme, A

    2004-07-01

    An interface between the separation technique (capillary electrophoresis) and the analytical technique (Inductively Coupled Plasma - Mass Spectrometer) was developed. In that sense, bibliographic and parametric studies allowed to define necessary conditions for the good working of both techniques. The results obtained led to the realisation of an interface capillary electrophoresis / ICP-MS (CE / ICP-MS). This one was experimentally validated on classical separations (alkalis / earth-alkalis and lanthanides) and the detection limit of the analytical system was determined equal to 4 x 10{sup -11} mol.L{sup -1} for plutonium. This result exhibits a gain in detection limit of a factor higher than 10{sup 4} compared to the capillary electrophoresis in standard detection (UV). The studies were made in order to check the capacity of the CE / ICP-MS coupling as a speciation instrument for actinides at trace level and to define the associated analytical procedures. The coupling turned out to be a suited instrument for the determination of absolute electrophoretic mobilities at infinite dilution (physico-chemical property which allows to predict the migration time of an ion under an electrical field in a given electrolyte), for the determination of thermodynamic constants and for the separation of different actinide oxidation states in solution. (author)

  5. Characterization of national food agency shrimp and plaice reference materials for trace elements and arsenic species by atomic and mass spectrometric techniques

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pedersen, Gitte Alsing; McLaren, J. W.

    1997-01-01

    The National Food Agency (NFA) of Denmark has produced and characterized NFA Plaice and NFA Shrimp reference materials (RMs) for the control of the accuracy of trace element and arsenic species determinations in similar seafood samples, The physical preparation of the materials included dissectio...

  6. Use of an ultra-clean sampling technique with inductively coupled plasma-mass spectrometry to determine trace-element concentrations in water from the Kirkwood-Cohansey Aquifer system, coastal plain, New Jersey

    Science.gov (United States)

    Ivahnenko, Tamara; Szabo, Zoltan; Hall, G.S.

    1996-01-01

    Water samples were collected during 1993 from 22 public supply wells screened in the Kirkwood-Cohansey aquifer system; concentrations of 18 trace elements were determined primarily by using inductively coupled plasma-mass spectrometry (ICP-MS) techniques, though graphite furnace atomic adsorption, hydride generation, and cold- vapor flameless atomic adsorption techniques were used for thallium, arsenic, and mercury, respectively, at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL). In addition, laboratory measurements of alkalinity and turbidity were made. The ground-water samples were collected by using ultra-clean sampling protocols developed by the USGS for collecting ground-water samples in areas with water containing low concentrations of trace elements. This technique is based on recently gained experience in sampling surface water for these elements. Field parameters (water temperature, specific conductance, pH, and dissolved-oxygen concentration) were monitored prior to sample collection. Three equipment blanks were collected to ensure that low-level trace-element contamination did not occur during sample collection. One split sample and a commercially- prepared reference standard were submitted to the NWQL o evaluate laboratory precision and accuracy, respectively. Trace-element concentrations in 10 sample splits and one equipment blank were also determined at the Rutgers University Chemistry Department laboratory. Results of the ICP-MS analyses and cold vapor flameless atomic absorption indicated that five trace elements-- cobalt, copper, lead, mercury, and nickel--were detectable in low concentrations (water samples sent to the Rutgers University Chemistry Department laboratory were, in general, in good agreement (within 10 percent) with those of the NWQL. Results of the analysis of the commercial standard agreed (within 5 percent) with the known concentrations of the trace elements. The quality-assurance data (three blanks, one

  7. Trace elements in adolescents

    OpenAIRE

    Barany, Ebba

    2002-01-01

    The major aim of the thesis was to monitor toxic and essential trace elements in a cohort of adolescents by blood and serum analyses, and describe the impact of different factors on the element concentrations. The adolescents were from the Swedish cities Uppsala and Trollhättan which represent different socioeconomic and environmental conditions, and were investigated at age 15 and 17. It was shown that an inductively coupled plasma mass spectrometry method was suitable for simultaneous deter...

  8. An off-line automated preconcentration system with ethylenediaminetriacetate chelating resin for the determination of trace metals in seawater by high-resolution inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Minami, Tomoharu; Konagaya, Wataru; Zheng, Linjie; Takano, Shotaro; Sasaki, Masanobu; Murata, Rena; Nakaguchi, Yuzuru; Sohrin, Yoshiki

    2015-01-07

    A novel automated off-line preconcentration system for trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in seawater was developed by improving a commercially available solid-phase extraction system SPE-100 (Hiranuma Sangyo). The utilized chelating resin was NOBIAS Chelate-PA1 (Hitachi High-Technologies) with ethylenediaminetriacetic acid and iminodiacetic acid functional groups. Parts of the 8-way valve made of alumina and zirconia in the original SPE-100 system were replaced with parts made of polychlorotrifluoroethylene in order to reduce contamination of trace metals. The eluent pass was altered for the back flush elution of trace metals. We optimized the cleaning procedures for the chelating resin column and flow lines of the preconcentration system, and developed a preconcentration procedure, which required less labor and led to a superior performance compared to manual preconcentration (Sohrin et al.). The nine trace metals were simultaneously and quantitatively preconcentrated from ∼120 g of seawater, eluted with ∼15 g of 1M HNO3, and determined by HR-ICP-MS using the calibration curve method. The single-step preconcentration removed more than 99.998% of Na, K, Mg, Ca, and Sr from seawater. The procedural blanks and detection limits were lower than the lowest concentrations in seawater for Mn, Ni, Cu, and Pb, while they were as low as the lowest concentrations in seawater for Al, Fe, Co, Zn, and Cd. The accuracy and precision of this method were confirmed by the analysis of reference seawater samples (CASS-5, NASS-5, GEOTRACES GS, and GD) and seawater samples for vertical distribution in the western North Pacific Ocean. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Trace elements and human fertility.

    OpenAIRE

    Stovell, Alex Gordon.

    1999-01-01

    Methods were developed and validated for the analysis of trace elements in human scalp hair, blood serum, ovarian follicular fluid and seminal plasma by inductively coupled plasma mass spectrometry (ICP-MS). An interlaboratory comparison was also undertaken to compare the analysis of biological materials by ICP-MS with instrumental neutron activation analysis (INAA). Preliminary trace element protein speciation experiments were carried out using size exclusion high performance liquid chromato...

  10. Exploiting flow injection and sequential injection for trace metal determinations in conjunction with detection by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    Despite their excellent analytical chemical capacities, Electrothermal Atomic Absorption Spectrometry (ETAAS) and Inductively Coupled Plasma Mass Spectrometry (ICPMS), nevertheless, often require suitable pretreatment of the sample material in order to obtain the necessary sensitivity...

  11. Determination of trace metal concentrations in ginseng (Panax Quinquefolius (American)) roots for forensic comparison using Inductively Coupled Plasma Mass-Spectrometry.

    Science.gov (United States)

    Peake, Barrie M; Tong, Alfred Y C; Wells, William J; Harraway, John A; Niven, Brian E; Weege, Butch; LaFollette, Douglas J

    2015-06-01

    The trace metal content of roots of samples of the American ginseng natural herbal plant species (Panax quinquefolius) was investigated as a means of differentiating between this species grown on Wisconsin and New Zealand farms, and from Canadian and Chinese sources. ICP-MS measurements were undertaken by ashing samples of the roots and then digestion with conc. HNO3 and H2O2. There was considerable variation in the concentrations of 28 detectable elements along the length of a root, between different roots, between different farms/sources and between different countries. Statistical processing of the log-transformed concentration data was undertaken using principal component analysis (PCA) and discriminant function analysis (DFA). Although PCA showed some differentiation between samples, a much clearer discrimination of the Panax quinquefolius species of ginseng from the four countries was observed using DFA. 88% of the variation between countries could be accounted for by only using discriminant function 1 while 80% of the remaining 12% of the variation between countries is accounted for by discriminant function 2. The Fisher Classification Functions classify 98% of the 87 samples to the correct country of origin with 97% of the cross-validated cases correctly classified. The predictive ability of this DFA model was further tested by constructing 100 discriminant models each using a random selection of the data for two thirds of the 87 sampled ginseng root tops, and then using the resulting classification functions to determine correctly the country of origin of the remaining third of the cases. The mean success rate of the 100 classifications was 92%. These results suggest that measurement and statistical analysis of just the trace metal content of the roots of Panax quinquefolius promises to be an excellent predictor of the country of origin of this ginseng species. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Analysis of trace metals (Cu, Cd, Pb, and Fe) in seawater using single batch nitrilotriacetate resin extraction and isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Lee, Jong-Mi; Boyle, Edward A.; Echegoyen-Sanz, Yolanda; Fitzsimmons, Jessica N.; Zhang Ruifeng; Kayser, Richard A.

    2011-01-01

    A simple and accurate low-blank method has been developed for the analysis of total dissolved copper, cadmium, lead, and iron in a small volume (1.3-1.5 mL per element) of seawater. Pre-concentration and salt-separation of a stable isotope spiked sample are achieved by single batch extraction onto nitrilotriacetate (NTA)-type Superflow chelating resin beads (100-2400 beads depending on the element). Metals are released into 0.1-0.5 M HNO 3 , and trace metal isotope ratios are determined by ICPMS. The benefit of this method compared to our previous Mg(OH) 2 coprecipitation method is that the final matrix is very dilute so cone-clogging and matrix sensitivity suppression are minimal, while still retaining the high accuracy of the isotope dilution technique. Recovery efficiencies are sensitive to sample pH, number of resin beads added, and the length of time allowed for sample-resin binding and elution; these factors are optimized for each element to yield the highest recovery. The method has a low procedural blank and high sensitivity sufficient for the analysis of pM-nM open-ocean trace metal concentrations. Application of this method to samples from the Bermuda Atlantic Time-Series Study station provides oceanographically consistent Cu, Cd, Pb, and Fe profiles that are in good agreement with other reliable data for this site. In addition, the method can potentially be modified for the simultaneous analysis of multiple elements, which will be beneficial for the analysis of large number of samples.

  13. Analysis of trace metals (Cu, Cd, Pb, and Fe) in seawater using single batch nitrilotriacetate resin extraction and isotope dilution inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Mi [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Boyle, Edward A., E-mail: eaboyle@mit.edu [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Echegoyen-Sanz, Yolanda; Fitzsimmons, Jessica N. [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Zhang Ruifeng [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062 (China); Kayser, Richard A. [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-02-07

    A simple and accurate low-blank method has been developed for the analysis of total dissolved copper, cadmium, lead, and iron in a small volume (1.3-1.5 mL per element) of seawater. Pre-concentration and salt-separation of a stable isotope spiked sample are achieved by single batch extraction onto nitrilotriacetate (NTA)-type Superflow chelating resin beads (100-2400 beads depending on the element). Metals are released into 0.1-0.5 M HNO{sub 3}, and trace metal isotope ratios are determined by ICPMS. The benefit of this method compared to our previous Mg(OH){sub 2} coprecipitation method is that the final matrix is very dilute so cone-clogging and matrix sensitivity suppression are minimal, while still retaining the high accuracy of the isotope dilution technique. Recovery efficiencies are sensitive to sample pH, number of resin beads added, and the length of time allowed for sample-resin binding and elution; these factors are optimized for each element to yield the highest recovery. The method has a low procedural blank and high sensitivity sufficient for the analysis of pM-nM open-ocean trace metal concentrations. Application of this method to samples from the Bermuda Atlantic Time-Series Study station provides oceanographically consistent Cu, Cd, Pb, and Fe profiles that are in good agreement with other reliable data for this site. In addition, the method can potentially be modified for the simultaneous analysis of multiple elements, which will be beneficial for the analysis of large number of samples.

  14. Osteoporosis and trace elements

    DEFF Research Database (Denmark)

    Aaseth, J.; Boivin, G.; Andersen, Ole

    2012-01-01

    More than 200 million people are affected by osteoporosis worldwide, as estimated by 2 million annual hip fractures and other debilitating bone fractures (vertebrae compression and Colles' fractures). Osteoporosis is a multi-factorial disease with potential contributions from genetic, endocrine...... in new bone and results in a net gain in bone mass, but may be associated with a tissue of poor quality. Aluminum induces impairment of bone formation. Gallium and cadmium suppresses bone turnover. However, exact involvements of the trace elements in osteoporosis have not yet been fully clarified...

  15. Application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to investigate trace metal spatial distributions in human tooth enamel and dentine growth layers and pulp

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Daniel; Amarasiriwardena, Dulasiri; Goodman, Alan H. [School of Natural Science, Hampshire College, 01002, Amherst, MA (United States)

    2004-03-01

    Human tooth enamel provides a nearly permanent and chronological record of an individual's nutritional status and anthropogenic trace metal exposure during development; it might thus provide an excellent bio archive. We investigated the micro-spatial distribution of trace metals (Cu, Fe, Mg, Sr, Pb, and Zn) in 196 x 339 {mu}m{sup 2} raster pattern areas (6.6 x 10{sup 4} {mu}m{sup 2}) in a deciduous tooth using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Ablated areas include prenatal and postnatal enamel, the neonatal line, the dentine-enamel junction (DEJ), dentine, and the dentine-pulp junction. Topographic variations in the surface elemental distribution of lead, zinc, strontium, and iron intensities in a deciduous tooth revealed heterogeneous distribution within and among regions. {sup 43}Ca normalized elemental intensities showed the following order: Sr>Mg>>Zn>Pb>Fe>Cu. Elevated zinc and lead levels were present in the dental pulp region and at the neonatal line. This study demonstrates the ability of LA-ICP-MS to provide unique elemental distribution information in micro spatial areas of dental hard tissues. Elemental distribution plots could be useful in decoding nutrition and pollution information embedded in their bio apatite structure. (orig.)

  16. Stir-bar-sorptive extraction and liquid desorption combined with large-volume injection gas chromatography-mass spectrometry for ultra-trace analysis of musk compounds in environmental water matrices.

    Science.gov (United States)

    Silva, Ana Rita M; Nogueira, J M F

    2010-03-01

    Stir-bar-sorptive extraction with liquid desorption followed by large-volume injection and capillary gas chromatography coupled to mass spectrometry in selected ion monitoring acquisition mode (SBSE-LD/LVI-GC-MS(SIM)) has been developed to monitor ultra-traces of four musks (celestolide (ADBI), galaxolide (HHCB), tonalide (AHTN) and musk ketone (MK)) in environmental water matrices. Instrumental calibration (LVI-GC-MS(SIM)) and experimental conditions that could affect the SBSE-LD efficiency are discussed. Assays performed on 30-mL water samples spiked at 200 ng L(-1) under optimized experimental conditions yielded recoveries ranging from 83.7 ± 8.1% (MK) to 107.6 ± 10.8% (HHCB). Furthermore, the experimental data were in very good agreement with predicted theoretical equilibria described by octanol-water partition coefficients (K (PDMS/W) ≈ K (O/W)). The methodology also showed excellent linear dynamic ranges for the four musks studied, with correlation coefficients higher than 0.9961, limits of detection and quantification between 12 and 19 ng L(-1) and between 41 and 62 ng L(-1), respectively, and suitable precision (ultra-trace level, overcoming several disadvantages presented by other sample-preparation techniques.

  17. Next generation offline approaches to trace organic compound speciation: Approaching comprehensive speciation with soft ionization and very high resolution tandem mass spectrometry

    Science.gov (United States)

    Khare, P.; Marcotte, A.; Sheu, R.; Ditto, J.; Gentner, D. R.

    2017-12-01

    Intermediate- and semi-volatile organic compounds (IVOCs and SVOCs) have high secondary organic aerosol (SOA) yields, as well as significant ozone formation potentials. Yet, their emission sources and oxidation pathways remain largely understudied due to limitations in current analytical capabilities. Online mass spectrometers are able to collect real time data but their limited mass resolving power renders molecular level characterization of IVOCs and SVOCs from the unresolved complex mixture unfeasible. With proper sampling techniques and powerful analytical instrumentation, our offline tandem mass spectrometry (i.e. MS×MS) techniques provide molecular-level and structural identification over wide polarity and volatility ranges. We have designed a novel analytical system for offline analysis of gas-phase SOA precursors collected on custom-made multi-bed adsorbent tubes. Samples are desorbed into helium via a gradual temperature ramp and sample flow is split equally for direct-MS×MS analysis and separation via gas chromatography (GC). The effluent from GC separation is split again for analysis via atmospheric pressure chemical ionization quadrupole time-of-flight mass spectrometry (APCI-Q×TOF) and traditional electron ionization mass spectrometry (EI-MS). The compounds for direct-MS×MS analysis are delivered via a transfer line maintained at 70ºC directly to APCI-Q×TOF, thus preserving the molecular integrity of thermally-labile, or other highly-reactive, organic compounds. Both our GC-MS×MS and direct-MS×MS analyses report high accuracy parent ion masses as well as information on molecular structure via MS×MS, which together increase the resolution of unidentified complex mixtures. We demonstrate instrument performance and present preliminary results from urban atmospheric samples collected from New York City with a wide range of compounds including highly-functionalized organic compounds previously understudied in outdoor air. Our work offers new

  18. On-line immunoaffinity column-liquid chromatography-tandem mass spectrometry method for trace analysis of diuron in wastewater treatment plant effluent sample.

    Science.gov (United States)

    Zhang, Xiuli; Martens, Dieter; Krämer, Petra M; Kettrup, Antonius A; Liang, Xinmiao

    2006-11-10

    An on-line immunoaffinity column with liquid chromatography/tandem mass spectrometry (IAC-LC-MS/MS) method for the determination of diuron in water matrices was described. This method used a sol-gel immunoaffinity column (20 mm x 4 mm I.D.) for on-line sample cleanup and enrichment, a monolithic analytical column (100 mm x 4.6 mm I.D.) for separation, and a triple quadrupole mass spectrometer for quantitation. The major challenges for the on-line set-up were discussed. The optimized on-line protocol was emphasized by the fact that low limit of quantitation (LOQ) of 1.0 ng/L was achieved with only 2.5-mL sample. In addition, a satisfactory accuracy ( approximately 90% of recovery) and precision (effect, the on-line IAC-LC-MS/MS analysis method can reliably determine diuron in wastewater treatment plant effluent sample.

  19. Microwave plasma ion sources for selected ion flow tube mass spectrometry: Optimizing their performance and detection limits for trace gas analysis

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Dryahina, Kseniya; Smith, D.

    2007-01-01

    Roč. 267, 1-3 (2007), s. 117-124 ISSN 1387-3806 R&D Projects: GA ČR GA202/06/0776 Institutional research plan: CEZ:AV0Z40400503 Keywords : microwave plasma ion source * selected ion flow tube mass spectrometry * SIFT-MS * breath analysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.411, year: 2007

  20. Analysis of biogenic carbonates by inductively coupled plasma-mass spectrometry (ICP-MS). Flow injection on-line solid-phase preconcentration for trace element determination in fish otoliths

    Energy Technology Data Exchange (ETDEWEB)

    Arslan, Z.; Paulson, A.J. [National Oceanic and Atmospheric Administration (NOAA), Northeast Fisheries Science Center (NFSC), James J. Howard Marine Sciences Laboratory, Highlands, NJ (United States)

    2002-04-01

    The aragonite deposits within the ear bones (otoliths) of teleost fish retain a chemical signal reflecting the life history of fish (similar to rings of trees) and the nature of fish habitats. Otoliths dissolved in acid solutions contain high concentrations of calcium and a variety of proteins. Elimination of matrix salts and organic interferences during preconcentration is essential for accurate determination of trace elements in otolith solutions by inductively coupled plasma-quadrupole mass spectrometry. An iminodiacetate-based chelating resin (Toyopearl AF-Chelate 650 M) has been used for on-line preconcentration and matrix separation for the determination of 31 transition and rare elements. Successful preconcentration of the elements was achieved at pH 5 by on-line buffering, except Mn which required pH 8.8. Sample solutions were loaded on to the column for 1 min at 3.2 mL min{sup -1}, and then eluted directly into the mass spectrometer with 4% v/v nitric acid. This procedure enabled up to 25-fold preconcentration with successful removal of the calcium matrix. The effect of heat-assisted oxidation with concentrated nitric acid was investigated to eliminate the organic matrix. It was found that heating to dryness after dissolution and further mineralization with the acid significantly improved the retention of the transition elements. The method was validated by analysis of a certified reference material produced from saggittal otoliths of emperor snapper (Lutjanus sebae), and then applied to the determination of trace metal concentrations in juvenile bluefin tuna (Thunnus thynnus) from the Western Pacific Ocean. (orig.)

  1. Analysis of biogenic carbonates by inductively coupled plasma-mass spectrometry (ICP-MS). Flow injection on-line solid-phase preconcentration for trace element determination in fish otoliths.

    Science.gov (United States)

    Arslan, Z; Paulson, A J

    2002-04-01

    The aragonite deposits within the ear bones (otoliths) of teleost fish retain a chemical signal reflecting the life history of fish (similar to rings of trees) and the nature of fish habitats. Otoliths dissolved in acid solutions contain high concentrations of calcium and a variety of proteins. Elimination of matrix salts and organic interferences during preconcentration is essential for accurate determination of trace elements in otolith solutions by inductively coupled plasma-quadrupole mass spectrometry. An iminodiacetate-based chelating resin (Toyopearl AF-Chelate 650 M) has been used for on-line preconcentration and matrix separation for the determination of 31 transition and rare elements. Successful preconcentration of the elements was achieved at pH 5 by on-line buffering, except Mn which required pH 8.8. Sample solutions were loaded on to the column for 1 min at 3.2 mL min(-1), and then eluted directly into the mass spectrometer with 4% v/v nitric acid. This procedure enabled up to 25-fold preconcentration with successful removal of the calcium matrix. The effect of heat-assisted oxidation with concentrated nitric acid was investigated to eliminate the organic matrix. It was found that heating to dryness after dissolution and further mineralization with the acid significantly improved the retention of the transition elements. The method was validated by analysis of a certified reference material produced from saggittal otoliths of emperor snapper ( Lutjanus sebae), and then applied to the determination of trace metal concentrations in juvenile bluefin tuna ( Thunnus thynnus) from the Western Pacific Ocean.

  2. Development of a transportable gas analyzer: thermal desorber / micro gas chromatograph / mass spectrometer coupling (m-TD / m-GC / MS). Application to on-line analysis of volatile organic compounds at traces level; Developpement d'un analyseur de gaz transportable: couplage thermodesorbeur / micro-chromatographe / spectrometre de masse (m-TD / m-CG / SM). Application a l'analyse en ligne des composes organiques volatils a l'etat de traces

    Energy Technology Data Exchange (ETDEWEB)

    Cozic, R.

    2004-06-01

    Volatile organic compounds (VOC) play a central part in the photochemical pollution of the atmosphere. Monitoring of these products in air became a need, because of their toxicity. Currently, traditional analytical methods of air have drawbacks. Instruments are too specific or the technique consists in trapping pollutants and then to turn over the sample to the laboratory for analysis. The subject of the thesis is the development of an on-site analytical technique, offering new prospects for air analysis. The developed transportable analyzer results from the coupling of a thermal desorber (m-TD), a micro gas chromatograph (m-GC) and a mass spectrometer (MS). The instrument makes it possible, in a few minutes, to perform qualitative and quantitative analysis of a very broad range of VOC at traces level. An example of on-site application of the analyzer relates to the monitoring of working atmospheres. (author)

  3. Determination of trace sulfur in biodiesel and diesel standard reference materials by isotope dilution sector field inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Amais, Renata S. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, São Carlos, SP (Brazil); Long, Stephen E. [Chemical Sciences Division, National Institute of Standards and Technology, Charleston, SC (United States); Nóbrega, Joaquim A. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, São Carlos, SP (Brazil); Christopher, Steven J., E-mail: steven.christopher@nist.gov [Chemical Sciences Division, National Institute of Standards and Technology, Charleston, SC (United States)

    2014-01-02

    Graphical abstract: -- Highlights: •Sulfur mass fractions are measured below 10 mg kg{sup −1} in diesel fuel materials. •SF-ICP-MS resolves molecular interferences, including oxygen and sulfur hydrides. •A detection limit of 0.7 mg kg{sup −1} (in the fuel sample) was obtained. -- Abstract: A method is described for quantification of sulfur at low concentrations on the order of mg kg{sup −1} in biodiesel and diesel fuels using isotope dilution and sector field inductively coupled plasma mass spectrometry (ID-SF-ICP-MS). Closed vessel microwave-assisted digestion was employed using a diluted nitric acid and hydrogen peroxide decomposition medium to reduce sample dilution volumes. Medium resolution mode was employed to eliminate isobaric interferences at {sup 32}S and {sup 34}S related to polyatomic phosphorus and oxygen species, and sulfur hydride species. The method outlined yielded respective limits of detection (LOD) and limits of quantification (LOQ) of 0.7 mg kg{sup −1} S and 2.5 mg kg{sup −1} S (in the sample). The LOD was constrained by instrument background counts at {sup 32}S but was sufficient to facilitate value assignment of total S mass fraction in NIST SRM 2723b Sulfur in Diesel Fuel Oil at 9.06 ± 0.13 mg kg{sup −1}. No statistically significant difference at a 95% confidence level was observed between the measured and certified values for certified reference materials NIST SRM 2773 B100 Biodiesel (Animal-Based), CENAM DRM 272b and NIST SRM 2723a Sulfur in Diesel Fuel Oil, validating method accuracy.

  4. Determination of major, minor and trace elements in rock samples by laser ablation inductively coupled plasma mass spectrometry: Progress in the utilization of borate glasses as targets

    International Nuclear Information System (INIS)

    Leite, Tacito Dantas F.; Escalfoni, Rainerio; Fonseca, Teresa Cristina O. da; Miekeley, Norbert

    2011-01-01

    The present work is a continuation of a research study performed at our laboratory aiming at the multielement analysis of rock samples (basalts and shale) by inductively coupled plasma mass spectrometry in combination with laser ablation using borate glasses as analytical targets. Argon, nitrogen-argon mixtures and helium were evaluated as cell gases, the latter confirming its better performance. Different operational parameters of the laser, such as gas flow, energy, focus, scanning speed and sampling frequency were optimized. External calibration was made with standards prepared by fusion of geological reference materials (basalts 688 and BCR-2, obsidian SRM 278, and shale SGR-1) of different mass fractions in the meta-tetra borate matrix. Coefficients of determination (R 2 ) were > 0.99 for 30 elements from o total of 40 determined. Method validation was then performed using additional certified reference materials (BHVO-2, BIR-1, SCo-1) produced as borate targets in a similar way. Accuracies were better than 10% for most of the elements studied and analytical precisions, calculated from the residual standard deviations of calibration curves were, typically, between 6% and 10%. Additionally, the semiquantitative TotalQuant (registered) technique was applied, which gave, within the expected uncertainty for this calibration technique, concordant results when compared to the quantitative external calibration procedure. Both methods were then used for the analysis of marine shale samples, which are of great geological interest in petroleum prospecting.

  5. A new HF-resistant tandem spray chamber for improved determination of trace elements and Pb isotopes using inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Krachler, Michael; Rausch, Nicole; Feuerbacher, Helmut; Klemens, Patrick

    2005-01-01

    The use of a new HF-resistant tandem spray chamber arrangement consisting of a cyclonic spray chamber and a Scott-type spray chamber made from PFA and PEEK provides a straightforward approach for improving the performance of inductively coupled-mass spectrometry (ICP-MS). The characteristics of the tandem spray chamber were critically evaluated against a PEEK cyclonic and a PFA Scott-type spray chamber, respectively. Sensitivity across the entire mass range was increased by about three times compared to the conventional setup utilizing only one spray chamber. Precision of the results, especially at low signal intensities, improved by 160% and 31% compared to the cyclonic and Scott-type spray chamber, respectively. Using the tandem spray chamber, the oxide formation rate was lowered by about 50%. Signals as low as 30 counts could be determined under routine measurement conditions with a RSD of 2.4% thus allowing to precisely quantify small concentration differences at the ng l -1 concentration level. The excellent precision (0.02-0.07%) of 206 Pb / 207 Pb and 206 Pb / 208 Pb ratios determined in pore water samples was rather limited by the instrumental capabilities of the single collector ICP-MS instrument than by the performance of the tandem spray chamber

  6. Dissolved rare earth elements in the central-western sector of the Ross Sea, Southern Ocean: Geochemical tracing of seawater masses.

    Science.gov (United States)

    Turetta, Clara; Barbaro, Elena; Capodaglio, Gabriele; Barbante, Carlo

    2017-09-01

    The present essay contributes to the existing literature on rare earth elements (REEs) in the southern hemisphere by presenting the first data, to our knowledge, on the vertical profiles of dissolved REEs in 71 samples collected in the central-western sector of the Ross Sea (Southern Ocean-SO). The REEs were measured in the water samples collected during the 2002-2003 and 2005-2006 austral summers. 4 samples were collected and analysed in the framework of a test experiment, as part of the WISSARD Project (Whillans Ice Stream Subglacial Access Research Drilling). Our results show significant differences between the REE patterns of the main water masses present in the SO: we could observe specific signature in the High Salinity Shelf Water (HSSW), Ice Shelf Water (ISW) and Low Salinity Shelf Water (LSSW). A significant increase in Terbium (Tb) concentration was observed in the HSSW and ISW, the two principal water masses contributing to the formation of Antarctic Bottom Water (AABW) in the Ross Sea area, and in LSSW. Some of the HSSW samples show enrichment in Neodymium (Nd). Dissolved REE could therefore be used as tracers to understand the deep circulation of the SO (Pacific sector). We hypothesize that: (I) the characteristic dissolved REE pattern may derive from the composition of source area and from the hydrothermal activity of the central-western area of the Ross Sea; (II) the Tb anomaly observed in the AABW on the South Australian platform could be partially explained by the contribution of AABW generated in the Ross Sea region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Multi-residue method for trace level determination of pharmaceuticals in environmental samples using liquid chromatography coupled to triple quadrupole mass spectrometry.

    Science.gov (United States)

    Grabic, Roman; Fick, Jerker; Lindberg, Richard H; Fedorova, Ganna; Tysklind, Mats

    2012-10-15

    A multi-residue method for the simultaneous determination of more than 90 pharmaceuticals in water samples was developed and validated. The developed method utilizes a single liquid chromatography-tandem mass spectrometry (LC-MS/MS) run after sample enrichment using solid-phase extraction (SPE). The pharmaceuticals included in this method were chosen based on their potency (effect/concentration ratio) and potential to bioaccumulate in fish. Because the selection was based on ecotoxicological criteria and not on ease of detection, the pharmaceuticals have a wide range of physico-chemical properties and represent 27 distinct classes. No method for surface, waste water or similar matrices was previously described for 52 of the 100 target analytes. Four chromatographic columns were tested to optimize the separation prior to detection by mass spectrometry (MS). The resulting method utilizes a Hypersil Gold aQ column. Three different water matrices were tested during method validation: Milli-Q water, surface water (river water from the Umea River) and effluent from the Umea waste water treatment plant (WWTP). Four of the selected pharmaceuticals exhibited poor method efficiency in all matrices. Amiodarone, Dihydroergotamine, Perphenazine and Terbutalin were omitted from the final analytical method. In addition, five compounds were excluded from the method for surface water (Atorvastatin, Chloropromazin, Dipyridamol, Furosemid and Ranitidin) and three other pharmaceuticals (Glibenclamid, Glimepirid and Meclozine) from waste water method respectively. Absolute recoveries were above 70% for Milli-Q water, surface water, and sewage effluent for most pharmaceuticals. The limits of quantification (LOQs) ranged from 0.05 to 50 ng L(-1) (median 5 ng L(-1)). The use of matrix-matched standards led to the elimination of ionization enhancement or suppression. The recoveries of the method for real matrices were in the range of 23-134% for surface water (only three compounds were

  8. Rapid and effective sample cleanup based on graphene oxide-encapsulated core-shell magnetic microspheres for determination of fifteen trace environmental phenols in seafood by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Pan, Sheng-Dong; Chen, Xiao-Hong; Shen, Hao-Yu; Li, Xiao-Ping; Cai, Mei-Qiang; Zhao, Yong-Gang; Jin, Mi-Cong

    2016-05-05

    In this study, graphene oxide-encapsulated core-shell magnetic microspheres (GOE-CS-MM) were fabricated by a self-assemble approach between positive charged poly(diallyldimethylammonium) chloride (PDDA)-modified Fe3O4@SiO2 and negative charged GO sheets via electrostatic interaction. The as-prepared GOE-CS-MM was carefully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer analysis (VSM), and X-ray photoelectron spectroscopy (XPS), and was used as a cleanup adsorbent in magnetic solid-phase extraction (MSPE) for determination of 15 trace-level environmental phenols in seafood coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS). The obtained results showed that the GOE-CS-MM exhibited excellent cleanup efficiency and could availably reduce the matrix effect. The cleanup mechanisms were investigated and referred to π-π stacking interaction and hydrogen bond between GOE-CS-MM and impurities in the extracts. Moreover, the extraction and cleanup conditions of GOE-CS-MM toward phenols were optimized in detail. Under the optimized conditions, the limits of detection (LODs) were found to be 0.003-0.06 μg kg(-1), and satisfactory recovery values of 84.8-103.1% were obtained for the tested seafood samples. It was confirmed that the developed method is simple, fast, sensitive, and accurate for the determination of 15 trace environmental phenols in seafood samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Determination of trace elements in medicinal activated charcoal using slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry with low vaporization temperature.

    Science.gov (United States)

    Chen, Chien-Chou; Jiang, Shiuh-Jen; Sahayam, A C

    2015-01-01

    The determination of Cd, Sb, Te, Hg, Tl and Pb in medicinal activated charcoal by ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) was described. EDTA was used as the modifier to enhance the volatility of elements studied. The influences of instrument operating conditions and slurry preparation on the ion signals were studied. A relatively low vaporization temperature of 1000°C was used, which separated the analyte from the major matrix components that improved ion signals. The method has been applied to determine Cd, Sb, Te, Hg, Tl and Pb in an NIST SRM 1633b Coal Fly Ash reference material and three brands of medicinal activated charcoal capsules using isotope dilution and standard addition calibration methods. The concentrations that are in ng g(-1) levels were in good agreement between different calibration methods. The precision between sample replicates was better than 7% with USS-ETV-ICP-MS technique. The method detection limit estimated from standard addition curves was 0.4, 0.3, 0.3, 0.3, 0.04 and 0.9 ng g(-1) for Cd, Sb, Te, Hg, Tl and Pb, respectively, in original medicinal activated charcoal. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Trace analysis of selected hormones and sterols in river sediments by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Matić, Ivana; Grujić, Svetlana; Jauković, Zorica; Laušević, Mila

    2014-10-17

    In this paper, development and optimization of new LC-MS method for determination of twenty selected hormones, human/animal and plant sterols in river sediments were described. Sediment samples were prepared using ultrasonic extraction and clean up with silica gel/anhydrous sodium sulphate cartridge. Extracts were analyzed by liquid chromatography-linear ion trap-tandem mass spectrometry, with atmospheric pressure chemical ionization. The optimized extraction parameters were extraction solvent (methanol), weight of the sediment (2 g) and time of ultrasonic extraction (3× 10 min). Successful chromatographic separation of hormones (estriol and estrone, 17α- and 17β-estradiol) and four human/animal sterols (epicoprostanol, coprostanol, α-cholestanol and β-cholestanol) that have identical fragmentation reactions was achieved. The developed and optimized method provided high recoveries (73-118%), low limits of detection (0.8-18 ng g(-1)) and quantification (2.5-60 ng g(-1)) with the RSDs generally lower than 20%. Applicability of the developed method was confirmed by analysis of six river sediment samples. A widespread occurrence of human/animal and plant sterols was found. The only detected hormone was mestranol in just one sediment sample. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography-quadrupole-linear ion trap-mass spectrometry.

    Science.gov (United States)

    Pareja, Lucía; Martínez-Bueno, M J; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, A R

    2011-07-29

    A multiresidue method was developed for the quantification and confirmation of 70 pesticides in paddy field water. After its filtration, water was injected directly in a liquid chromatograph coupled to a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). The list of target analytes included organophosphates, phenylureas, sulfonylureas, carbamates, conazoles, imidazolinones and others compounds widely used in different countries where rice is cropped. Detection and quantification limits achieved were in the range from 0.4 to 80 ng L(-1) and from 2 to 150 ng L(-1), respectively. Correlation coefficients for the calibration curves in the range 0.1-50 μg L(-1) were higher than 0.99 except for diazinon (0.1-25 μg L(-1)). Only 9 pesticides presented more than 20% of signal suppression/enhancement, no matrix effect was observed in the studied conditions for the rest of the target pesticides. The method developed was used to investigate the occurrence of pesticides in 59 water samples collected in paddy fields located in Spain and Uruguay. The study shows the presence of bensulfuron methyl, tricyclazole, carbendazim, imidacloprid, tebuconazole and quinclorac in a concentration range from 0.08 to 7.20 μg L(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Determination of trace elements in biological samples treated with formic acid by inductively coupled plasma mass spectrometry using a microconcentric nebulizer

    International Nuclear Information System (INIS)

    Tormen, Luciano; Gil, Raul A.; Frescura, Vera L.A.; Dante Martinez, Luis; Curtius, Adilson J.

    2010-01-01

    A simple and fast method for the determination of As, Ba, Cd, Co, Cu, Fe, Ga, Mn, Mo, Ni, Pb, Rb, Se, Sr, Tl, U, V and Zn in biological samples by inductively coupled plasma mass spectrometry (ICP-MS), after sample solubilization with formic acid and introduction by a microconcentric nebulizer, is proposed. The sample is mixed with formic acid, kept at 90 o C for one hour and then diluted with nitric acid aqueous solution to a 50% v/v formic acid and 1% v/v nitric acid final concentrations. The final sample solution flow rate for introduction into the plasma was 30 μL min -1 . The optimized and adopted nebulizer gas flow rate was 0.7 L min -1 and RF power was 800 W. These conditions are very different than those normally used when a conventional nebulizer is employed. Rodhium was used as internal standard. External calibration against aqueous standard solutions, without formic acid, could be used for quantification, except for As, Se and Zn. However, external calibration with 50% formic acid allows the determination of all analytes with high accuracy and it is recommended. The detection limits were between 0.0005 (Tl) and 0.22 mg kg -1 (Fe) and the precision expressed by the relative standard deviations (RSD) were between 0.2% (Sr) and 3.5% (Ga). Accuracy was validated by the analysis of four certified reference biological materials of animal tissues, comparing the results by linear regressions and by the t-test at a 95% confidence level. The recommended procedure avoids plasma instability and carbon deposit on the cones.

  13. Trace determination of perfluorooctane sulfonate and perfluorooctanoic acid in environmental samples (surface water, wastewater, biota, sediments, and sewage sludge) using liquid chromatography - Orbitrap mass spectrometry.

    Science.gov (United States)

    Zacs, D; Bartkevics, V

    2016-11-18

    An analytical method was established and validated for the analysis of the most frequently monitored representatives among the group of perfluorinated compounds (PFAS), namely, perfluorooctanoic acid (PFOA) and prefluorooctane sulfonate (PFOS) in environmental samples (surface water, wastewater, sediments, sewage sludge, and biota). High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing a heated electrospray ionization (HESI) interface operated in negative mode was used for the quantitative determination of these contaminants. HPLC separation of analytes was achieved using a reversed phase C18 (RP-C18) analytical column. The efficiency of various solid phase extraction (SPE) columns for the pre-concentration and clean-up as well as the performance of different ionization sources and detection modes for the instrumental determination were evaluated. The validation results indicate recoveries of analytes between 88 and 116%, while the intra-day and inter-day precision parameters in terms of relative standard deviations (RSDs) were in the range of 1.0-5.9% and 1.5-7.3%, respectively. The measured values for certified reference material (CRM) agreed with the provided reference values, revealing the accuracy of obtained concentrations in the range of 107-108%. The trueness of the method was verified by a successful participation in a proficiency testing (PT) program. These performance characteristics of the method permit reliable monitoring of PFOS and its derivatives in environmental samples according to the environmental quality standard (EQS) criteria regarding the maximum allowable concentrations and taking into account the annual average concentrations stated in Directive 2013/39/EU. The elaborated method was applied for the routine analysis of selected PFAS in environmental samples from the Baltic region. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions

    International Nuclear Information System (INIS)

    Chen, Wei-Ni; Jiang, Shiuh-Jen; Chen, Yen-Ling; Sahayam, A.C.

    2015-01-01

    Highlights: • Determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions in a single run. • Accurate analysis using isotope dilution and standard addition methods. • Vapor generation ICP-MS yielded superior detection limits compared to ETV-ICP-MS. • No sample dissolution increased sample through put. • Analysis of GBW09305 Cosmetic (Cream) reference material for accuracy. - Abstract: A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v L-cysteine, 0.5 μg mL −1 Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng g −1 for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample

  15. Exploiting dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) for sequential determination of trace elements in blood using a dilute-and-shoot procedure

    International Nuclear Information System (INIS)

    Lemos Batista, Bruno; Lisboa Rodrigues, Jairo; Andrade Nunes, Juliana; Oliveira Souza, Vanessa Cristina de; Barbosa, Fernando

    2009-01-01

    Inductively coupled plasma mass spectrometry with quadrupole (q-ICP-MS) and dynamic reaction cell (DRC-ICP-MS) were evaluated for sequential determination of As, Cd, Co, Cr, Cu, Mn, Pb, Se, Tl, V and Zn in blood. The method requires as little as 100 μL of blood. Prior to analysis, samples (100 μL) were diluted 1:50 in a solution containing 0.01% (v/v) Triton X-100 and 0.5% (v/v) nitric acid. The use of the DRC was only mandatory for Cr, Cu, V and Zn. For the other elements the equipment may be operated in a standard mode (q-ICP-MS). Ammonia was used as reaction gas. Selection of best flow rate of ammonium gas and optimization of the quadrupole dynamic band-pass tuning parameter (RPq) were carried out, using a ovine base blood for Cr and V and a synthetic matrix solution (SMS) for Zn and Cu diluted 1:50 and spiked to contain 1 μg L -1 of each element. Method detection limits (3 s) for 75 As, 114 Cd, 59 Co, 51 Cr, 63 Cu 55 Mn, 208 Pb, 82 Se, 205 Tl, 51 V, and 64 Zn were 14.0, 3.0, 11.0, 7.0, 280, 9.0, 3.0, 264, 0.7, 6.0 and 800 ng L -1 , respectively. Method validation was accomplished by the analysis of blood Reference Materials produced by the L'Institut National de Sante Publique du Quebec (Canada).

  16. Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Ni [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Jiang, Shiuh-Jen, E-mail: sjjiang@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Chen, Yen-Ling [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Sahayam, A.C. [National Centre for Compositional Characterisation of Materials (CCCM), Hyderabad (India)

    2015-02-20

    Highlights: • Determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions in a single run. • Accurate analysis using isotope dilution and standard addition methods. • Vapor generation ICP-MS yielded superior detection limits compared to ETV-ICP-MS. • No sample dissolution increased sample through put. • Analysis of GBW09305 Cosmetic (Cream) reference material for accuracy. - Abstract: A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v L-cysteine, 0.5 μg mL{sup −1} Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng g{sup −1} for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample.

  17. Epidemic contact tracing via communication traces.

    Science.gov (United States)

    Farrahi, Katayoun; Emonet, Rémi; Cebrian, Manuel

    2014-01-01

    Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

  18. Epidemic contact tracing via communication traces.

    Directory of Open Access Journals (Sweden)

    Katayoun Farrahi

    Full Text Available Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

  19. Parametric Trace Slicing

    Science.gov (United States)

    Rosu, Grigore (Inventor); Chen, Feng (Inventor); Chen, Guo-fang; Wu, Yamei; Meredith, Patrick O. (Inventor)

    2014-01-01

    A program trace is obtained and events of the program trace are traversed. For each event identified in traversing the program trace, a trace slice of which the identified event is a part is identified based on the parameter instance of the identified event. For each trace slice of which the identified event is a part, the identified event is added to an end of a record of the trace slice. These parametric trace slices can be used in a variety of different manners, such as for monitoring, mining, and predicting.

  20. Comparison of Gas Chromatography-Mass Spectrometry and Gas Chromatography-Tandem Mass Spectrometry with Electron Ionization and Negative-Ion Chemical Ionization for Analyses of Pesticides at Trace Levels in Atmospheric Samples

    Directory of Open Access Journals (Sweden)

    Renata Raina

    2008-01-01

    Full Text Available A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS in selected ion monitoring (SIM with gas chromatography-tandem mass spectrometry (GC-MS/MS in selected reaction monitoring (SRM mode with both electron ionization (EI and negative-ion chemical ionization (NCI are presented for over 50 pesticides ranging from organochlorines (OCs, organophosphorus pesticides (OPs and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin. The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations <100 pg µL−1 (<100 pg m−3 in air. No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5–10 pg µL−1 along with best confirmation (<25% RSD of ion ratio, while GC-NCI/SRM is recommended for use where added selectivity or confirmation is required (such as parathion-ethyl, tokuthion, carbofenothion. GC-EI/SRM at concentration <100 pg µL−1 was not suitable for most pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1–10 pg µL−1 for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT.

  1. Comparison of gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry with electron ionization and negative-ion chemical ionization for analyses of pesticides at trace levels in atmospheric samples.

    Science.gov (United States)

    Raina, Renata; Hall, Patricia

    2008-09-09

    A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) with gas chromatography-tandem mass spectrometry (GC-MS/MS) in selected reaction monitoring (SRM) mode with both electron ionization (EI) and negative-ion chemical ionization (NCI) are presented for over 50 pesticides ranging from organochlorines (OCs), organophosphorus pesticides (OPs) and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin). The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations air). No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5-10 pg microL(-1)) along with best confirmation (pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1-10 pg microL(-1)) for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT).

  2. Determination of trace amounts of rare-earth elements in highly pure neodymium oxide by sector field inductively coupled plasma mass spectrometry (ICP-SFMS) and high-performance liquid chromatography (HPLC) techniques

    International Nuclear Information System (INIS)

    Pedreira, W.R.; Sarkis, J.E.S.; Silva Queiroz, C.A. da; Rodrigues, C.; Tomiyoshi, I.A.; Abrao, A.

    2003-01-01

    Recently rare-earth elements (REE) have received much attention in fields of geochemistry and industry. Rapid and accurate determinations of them are increasingly required as industrial demands expand. Sector field inductively coupled plasma mass spectrometry (ICP-SFMS) with high-performance liquid chromatography (HPLC) has been applied to the determination of REE. HR ICP-MS was used as an element-selective detector for HPLC in highly pure materials. The separation of REE with HPLC helped to avoid erroneous analytical results due to spectral interferences. Sixteen elements (Sc, Y and 14 lanthanides) were determined selectively with the HPLC/ICP-SFMS system using a concentration gradient methods. The detection limits with the HPLC/ICP-SFMS system were about 0.5-10 pg mL -1 . The percentage recovery ranged from 90% to 100% for different REE. The %RSD of the methods varying between 2.5% and 4.5% for a set of five (n=5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two highly pure neodymium oxides samples (IPEN and Johnson Matthey Company) were performed. In short, the IPEN's materials which are highly pure (>99.9%) were successfully analyzed without spectral interferences

  3. Rapid and effective sample cleanup based on graphene oxide-encapsulated core–shell magnetic microspheres for determination of fifteen trace environmental phenols in seafood by liquid chromatography–tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Sheng-Dong; Chen, Xiao-Hong [Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010 (China); Ningbo Key Laboratory of Poison Research and Control, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010 (China); Shen, Hao-Yu [Ningbo Institute of Technology, Zhejiang University, Ningbo, Zhejiang 315100 (China); Li, Xiao-Ping [Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010 (China); Ningbo Key Laboratory of Poison Research and Control, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010 (China); Cai, Mei-Qiang [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); Zhao, Yong-Gang [Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010 (China); Ningbo Key Laboratory of Poison Research and Control, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010 (China); Jin, Mi-Cong, E-mail: jmcjc@163.com [Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010 (China); Ningbo Key Laboratory of Poison Research and Control, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010 (China)

    2016-05-05

    In this study, graphene oxide-encapsulated core–shell magnetic microspheres (GOE-CS-MM) were fabricated by a self-assemble approach between positive charged poly(diallyldimethylammonium) chloride (PDDA)-modified Fe{sub 3}O{sub 4}@SiO{sub 2} and negative charged GO sheets via electrostatic interaction. The as-prepared GOE-CS-MM was carefully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer analysis (VSM), and X-ray photoelectron spectroscopy (XPS), and was used as a cleanup adsorbent in magnetic solid-phase extraction (MSPE) for determination of 15 trace-level environmental phenols in seafood coupled to liquid chromatography–tandem mass spectrometry (LC–MS/MS). The obtained results showed that the GOE-CS-MM exhibited excellent cleanup efficiency and could availably reduce the matrix effect. The cleanup mechanisms were investigated and referred to π–π stacking interaction and hydrogen bond between GOE-CS-MM and impurities in the extracts. Moreover, the extraction and cleanup conditions of GOE-CS-MM toward phenols were optimized in detail. Under the optimized conditions, the limits of detection (LODs) were found to be 0.003–0.06 μg kg{sup −1}, and satisfactory recovery values of 84.8–103.1% were obtained for the tested seafood samples. It was confirmed that the developed method is simple, fast, sensitive, and accurate for the determination of 15 trace environmental phenols in seafood samples. - Highlights: • Novel graphene oxide-encapsulated core-shell magnetic microspheres (GOE-CS-MM) were fabricated by a self-assemble approach. • The as-prepared material GOE-CS-MM exhibited excellent cleanup efficiency and could availably reduce the matrix effect. • The cleanup mechanisms refer to π–π stacking interaction and hydrogen bond. • The developed MSPE–LC–MS/MS method was simple, fast, sensitive and accurate.

  4. Triethylamine-assisted Mg(OH)2 coprecipitation/preconcentration for determination of trace metals and rare earth elements in seawater by inductively coupled plasma mass spectrometry (ICP-MS).

    Science.gov (United States)

    Arslan, Zikri; Oymak, Tulay; White, Jeremy

    2018-05-30

    In this paper, we report an improved magnesium hydroxide, Mg(OH) 2 , coprecipitation method for the determination of 16 trace elements (Al, V, Cr, Mn, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Sb, Sn and Pb) and 18 rare earth elements (REEs), including Sc, Y, U and Th in seawater and estuarine water samples. The procedure involves coprecipitation of the trace elements and REEs on Mg(OH) 2 upon addition of a small volume of triethylamine (TEA) followed by analysis of the dissolved pellet solutions by inductively coupled plasma mass spectrometry (ICP-MS). Three-step sequential coprecipitation was carried out on 10 mL aliquots of seawater to eliminate the matrix ions and to preconcentrate the analytes of interest into a 1 mL final volume. Spike recoveries varied from 85% (Th) to 105% (Y). Calcium (Ca), sodium (Na) and potassium (K) matrices were virtually eliminated from the analysis solutions. Collision reaction interface (CRI) technology utilizing H 2 and He gases was employed to determine its effectiveness in removing the spectral interferences originating from the residual Mg matrix, TEA and plasma gases. H 2 was more effective than He in reducing spectral interferences from TEA and plasma gases. Limits of detection (LODs) ranged from 0.01 ng L -1 (Ho) to 72 ng L -1  (Al). The method was validated by using certified seawater (CASS-4) and estuarine water (SLEW-3) reference materials. Precision for five (n = 5) replicate measurements were between 1.2% (Pr) and 18% (Lu). Fe, Pb, Sn, and Zn impurities in TEA were significant in comparison to the levels in CASS-4 and SLEW-3, while relatively high background signals impacted determinations of low levels of Sc and Th. The effects of these hurdles on precision and accuracy were alleviated by measuring these elements in spiked CASS-4 and SLEW-3. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Alienation, Mass Society and Mass Culture.

    Science.gov (United States)

    Dam, Hari N.

    This monograph examines the nature of alienation in mass society and mass culture. Conceptually based on the "Gemeinschaft-Gesellschaft" paradigm of sociologist Ferdinand Tonnies, discussion traces the concept of alienation as it appears in the philosophies of Hegel, Marx, Kierkegaard, Sartre, and others. Dwight Macdonald's "A Theory of Mass…

  6. Trace elements and bone health.

    Science.gov (United States)

    Zofková, Ivana; Nemcikova, Petra; Matucha, Petr

    2013-08-01

    The importance of nutrition factors such as calcium, vitamin D and vitamin K for the integrity of the skeleton is well known. Moreover, bone health is positively influenced by certain elements (e.g., zinc, copper, fluorine, manganese, magnesium, iron and boron). Deficiency of these elements slows down the increase of bone mass in childhood and/or in adolescence and accelerates bone loss after menopause or in old age. Deterioration of bone quality increases the risk of fractures. Monitoring of homeostasis of the trace elements together with the measurement of bone density and biochemical markers of bone metabolism should be used to identify and treat patients at risk of non-traumatic fractures. Factors determining the effectivity of supplementation include dose, duration of treatment, serum concentrations, as well as interactions among individual elements. Here, we review the effect of the most important trace elements on the skeleton and evaluate their clinical importance.

  7. The Trace of Superusers

    DEFF Research Database (Denmark)

    Samson, Kristine; Abasolo, José

    2013-01-01

    of people’s everyday life.However, traces of culture, the routines and every day habits of immigrant culture can both emerge through informal colonization in the every day and be intentionally designed. By juxtaposing immigrant spatial traces in Santiago Centro with the intentionally designed traces......The city and its public spaces can be seen as a fragmented whole carrying meanings and traces of culture, use and politics with it. Whereas architects impose new stories and meanings on the urban fabric, the city itself is layered and assembled, a collective of social flows and routines a result...... of immigrant culture at Superkilen, Nørrebro in Copenhagen, this article seeks to discuss how traces influence public space, and how various ideologies and even politics are interwoven into the urban fabric by means of urban traces....

  8. What is Process Tracing actually tracing?

    DEFF Research Database (Denmark)

    Beach, Derek; Pedersen, Rasmus Brun

    and when we use PT case studies. First, there are differences in what we are actually tracing in the three variants, resulting in different methodological prescriptions for each variant. Second, the types of inferences being made are also different; the variants therefore have different analytical uses...

  9. Interactive Stable Ray Tracing

    DEFF Research Database (Denmark)

    Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

    2017-01-01

    Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

  10. Nuclear traces in glass

    International Nuclear Information System (INIS)

    Segovia A, M. de N.

    1978-01-01

    The charged particles produce, in dielectric materials, physical and chemical effects which make evident the damaged zone along the trajectory of the particle. This damaged zone is known as the latent trace. The latent traces can be enlarged by an etching of the detector material. This treatment attacks preferently the zones of the material where the charged particles have penetrated, producing concavities which can be observed through a low magnification optical microscope. These concavities are known as developed traces. In this work we describe the glass characteristics as a detector of the fission fragments traces. In the first chapter we present a summary of the existing basic theories to explain the formation of traces in solids. In the second chapter we describe the etching method used for the traces development. In the following chapters we determine some chatacteristics of the traces formed on the glass, such as: the development optimum time; the diameter variation of the traces and their density according to the temperature variation of the detector; the glass response to a radiation more penetrating than that of the fission fragments; the distribution of the developed traces and the existing relation between this ditribution and the fission fragments of 252 Cf energies. The method which has been used is simple and cheap and can be utilized in laboratories whose resources are limited. The commercial glass which has been employed allows the registration of the fission fragments and subsequently the realization of experiments which involve the counting of the traces as well as the identification of particles. (author)

  11. Tracing Planets in Circumstellar Discs

    Directory of Open Access Journals (Sweden)

    Uribe Ana L.

    2013-04-01

    Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

  12. Traces of Drosophila Memory

    Science.gov (United States)

    Davis, Ronald L.

    2012-01-01

    Summary Studies using functional cellullar imaging of living flies have identified six memory traces that form in the olfactory nervous system after conditioning with odors. These traces occur in distinct nodes of the olfactory nervous system, form and disappear across different windows of time, and are detected in the imaged neurons as increased calcium influx or synaptic release in response to the conditioned odor. Three traces form at, or near acquisition and co-exist with short-term behavioral memory. One trace forms with a delay after learning and co-exists with intermediate-term behavioral memory. Two traces form many hours after acquisition and co-exist with long-term behavioral memory. The transient memory traces may support behavior across the time-windows of their existence. The experimental approaches for dissecting memory formation in the fly, ranging from the molecular to the systems, make it an ideal system for dissecting the logic by which the nervous system organizes and stores different temporal forms of memory. PMID:21482352

  13. Application of ion chemistry to environmental trace gas analysis

    International Nuclear Information System (INIS)

    Hansel, A.; Wisthaler, A.

    2001-01-01

    Full text: In Werner Lindingers laboratory we have developed a mass spectrometric technique, named proton-transfer-reaction mass-spectrometry (PTR-MS), which utilizes positive ion chemistry to measure trace neutral concentrations in air. During the last few years PTR-MS has been used in food research, in medical applications, and in environmental applications to gain gas phase information of volatile organic compounds (VOCs) at parts per trillion (pptv) levels. The real time method relies on proton transfer reactions between H 3 O + primary ions and organic trace gases (VOCs) which have a higher proton affinity than water molecules. Organic trace gases such as hydrocarbons, carbonyls, alcohols, acetonitrile, and others can be monitored on-line. In this lecture we will discuss the mass spectrometric method and present recent results gained in the field of environmental trace gas analysis. (author)

  14. Intraoral gothic arch tracing.

    Science.gov (United States)

    Rubel, Barry; Hill, Edward E

    2011-01-01

    In order to create optimum esthetics, function and phonetics in complete denture fabrication, it is necessary to record accurate maxillo-mandibular determinants of occlusion. This requires clinical skill to establish an accurate, verifiable and reproducible vertical dimension of occlusion (VDO) and centric relation (CR). Correct vertical relation depends upon a consideration of several factors, including muscle tone, inter-dental arch space and parallelism of the ridges. Any errors made while taking maxillo-mandibular jaw relation records will result in dentures that are uncomfortable and, possibly, unwearable. The application of a tracing mechanism such as the Gothic arch tracer (a central bearing device) is a demonstrable method of determining centric relation. Intraoral Gothic arch tracers provide the advantage of capturing VDO and CR in an easy-to-use technique for practitioners. Intraoral tracing (Gothic arch tracing) is a preferred method of obtaining consistent positions of the mandible in motion (retrusive, protrusive and lateral) at a comfortable VDO.

  15. Trace analysis by TXRF

    International Nuclear Information System (INIS)

    Hockett, R.S.

    1995-01-01

    Total reflection X-Ray Fluorescence (TXRF) originally was developed for trace analysis of small residues but has become a widespread method for measuring trace surface metal contamination an semiconductor substrates. It is estimated that approximately 100 TXRF instruments are in se in the semiconductor industry worldwide, and approximately half that for residue analysis x analytical laboratories. TXRF instrumentation is available today for reaching detection limits d the order of 10 9 atoms/cm 2 . This review emphasizes some of the more recent developments in TXRF for trace analysis, in particular with the use of synchrotron x-ray sources (SR-TXRF). There is some promise of reaching 10 7 atoms/cm 2 detection limits for surface analysis of semi-conductor substrates. 19 refs

  16. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  17. Oscilloscope trace photograph digitizing system (TRACE)

    International Nuclear Information System (INIS)

    Richards, M.; Dabbs, R.D.

    1977-10-01

    The digitizing system allows digitization of photographs or sketches of waveforms and then the computer is used to reduce and analyze the data. The software allows for alignment, calibration, removal of baselines, removal of unwanted points and addition of new points which makes for a fairly versatile system as far as data reduction and manipulation are concerned. System considerations are introduced first to orient the potential user to the process of digitizing information. The start up and actual commands for TRACE are discussed. Detailed descriptions of each subroutine and program section are also provided. Three general examples of typical photographs are included. A partial listing of FAWTEK is made available. Once suitable arrays that contain the data are arranged, ''GO FA'' (active FAWTEK) and many mathematical operations to further analyze the data may be performed

  18. Implementation of suitable flow injection/sequential-sample separation/preconcentration schemes for determination of trace metal concentrations using detection by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Wang, Jianhua

    2002-01-01

    Various preconditioning procedures encomprising appropriate separation/preconcentration schemes in order to obtain optimal sensitivity and selectivity characteristics when using electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICPMS...

  19. TRACING CULPABLE IGNORANCE

    NARCIS (Netherlands)

    Peels, Rik

    2011-01-01

    In this paper, I respond to the following argument which several authors have presented. If we are culpable for some action, we act either from akrasia or from culpable ignorance. However, akrasia is highly exceptional and it turns out that tracing culpable ignorance leads to a vicious regress.

  20. Third order trace formula

    Indian Academy of Sciences (India)

    adjoint operator is bounded and the perturbation is ... Keywords. Trace formula; spectral shift function; perturbations of self-adjoint operators. 1. Introduction. Notations. .... j=1 j−1. ∑ k=0. Ar− j−1. Y(A + X)k X Aj−k−1, leading to the estimate. ∥. ∥.

  1. Third order trace formula

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 123; Issue 4. Third Order Trace Formula. Arup Chattopadhyay Kalyan B Sinha. Volume 123 Issue 4 November 2013 pp 547-575. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/pmsc/123/04/0547-0575 ...

  2. Standard Model Effective Potential from Trace Anomalies

    Directory of Open Access Journals (Sweden)

    Renata Jora

    2018-01-01

    Full Text Available By analogy with the low energy QCD effective linear sigma model, we construct a standard model effective potential based entirely on the requirement that the tree level and quantum level trace anomalies must be satisfied. We discuss a particular realization of this potential in connection with the Higgs boson mass and Higgs boson effective couplings to two photons and two gluons. We find that this kind of potential may describe well the known phenomenology of the Higgs boson.

  3. Epidemiology and trace elements.

    Science.gov (United States)

    Elwood, P C

    1985-08-01

    Basically, epidemiology is the making of measurements of known reproducibility, in a bias-free manner, on representative samples of subjects drawn from defined communities. Epidemiology has become a relatively precise science and its value in medicine is widely appreciated. So too are its limitations: the difficulties in achieving a high response rate, in identifying and controlling confounding factors in the examination of an association, and the ultimate difficulties in distinguishing causation from association. While the value of community-based studies seems to be recognized by those interested in man and his environment, the need for the strict application of epidemiological procedures, and the limitations imposed on conclusions drawn from studies in which these procedures have been compromised, does not seem to be adequately understood. There are certain known links between trace elements in the environment and disease: for example the level of iodine in soil and water and the prevalence of goitre; the level of fluoride in water and the prevalence of dental caries. The investigation of other possible associations is difficult for a number of reasons, including interrelationships between trace elements, confounding of trace element levels (and disease) with social and dietary factors, and the probability that relationships are generally weak. Two conditions in which associations are likely are cardiovascular disease and cancer. Despite research along a number of lines, the relevance of trace elements to cardiovascular disease is not clear, and certainly the apparent association with hardness of domestic water supply seems unlikely to be causal. The same general conclusion seems reasonable for cancer, and although there are a very few well established associations which are likely to be causal, such as exposure to arsenic and skin cancer, the role of trace elements is obscure, and likely to be very small.

  4. Limit of detection in the presence of instrumental and non-instrumental errors: study of the possible sources of error and application to the analysis of 41 elements at trace levels by inductively coupled plasma-mass spectrometry technique

    International Nuclear Information System (INIS)

    Badocco, Denis; Lavagnini, Irma; Mondin, Andrea; Tapparo, Andrea; Pastore, Paolo

    2015-01-01

    In this paper the detection limit was estimated when signals were affected by two error contributions, namely instrumental errors and operational-non-instrumental errors. The detection limit was theoretically obtained following the hypothesis testing schema implemented with the calibration curve methodology. The experimental calibration design was based on J standards measured I times with non-instrumental errors affecting each standard systematically but randomly among the J levels. A two-component variance regression was performed to determine the calibration curve and to define the detection limit in these conditions. The detection limit values obtained from the calibration at trace levels of 41 elements by ICP-MS resulted larger than those obtainable from a one component variance regression. The role of the reagent impurities on the instrumental errors was ascertained and taken into account. Environmental pollution was studied as source of non-instrumental errors. The environmental pollution role was evaluated by Principal Component Analysis technique (PCA) applied to a series of nine calibrations performed in fourteen months. The influence of the seasonality of the environmental pollution on the detection limit was evidenced for many elements usually present in the urban air particulate. The obtained results clearly indicated the need of using the two-component variance regression approach for the calibration of all the elements usually present in the environment at significant concentration levels. - Highlights: • Limit of detection was obtained considering a two variance component regression. • Calibration data may be affected by instrumental and operational conditions errors. • Calibration model was applied to determine 41 elements at trace level by ICP-MS. • Non instrumental errors were evidenced by PCA analysis

  5. Trace elements distribution in environmental compartments

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Juliana C. de; Peres, Sueli da Silva; Godoy, Maria Luiza D.P., E-mail: suelip@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-11-01

    Trace elements term defines the presence of low concentrations metals at environment. Some of them are considered biologically essential, as Co, Cu and Mn. Others can cause detriment to environment and human health, as Pb, Cd, Hg, As, Ti and U. A large number of them have radioactive isotopes, implying the evaluation of risks for human health should be done considering the precepts of environmental radiological protection. The ecosystem pollution with trace elements generates changes at the geochemistry cycle of these elements and in environmental quality. Soils have single characteristics when compared with another components of biosphere (air, water and biota), cause they introduce themselves not only as a drain towards contaminants, but also as natural buffer that control the transport of chemical elements and other substances for atmosphere, hydrosphere and biota. The main purpose of environmental monitoring program is to evaluate the levels of contaminants in the various compartments of the environment: natural or anthropogenic, and to assess the contribution of a potential contaminant source on the environment. Elemental Composition for the collected samples was determined by inductively coupled plasma mass spectroscopy. The main objective of this work was to evaluate the map baseline of concentration of interest trace elements in environmental samples of water, sediment and soil from Environmental Monitoring Program of Instituto de Radioprotecao e Dosimetria (IRD). The samples were analyzed using an inductively coupled plasma mass spectrometer (ICP-MS) at IRD. >From the knowledge of trace elements concentrations, could be evaluated the environmental quality parameters at the studied ecosystems. The data allowed evaluating some relevant aspects of the study of trace elements in soil and aquatic systems, with emphasis at the distribution, concentration and identification of main anthropic sources of contamination at environment. (author)

  6. Trace elements distribution in environmental compartments

    International Nuclear Information System (INIS)

    Queiroz, Juliana C. de; Peres, Sueli da Silva; Godoy, Maria Luiza D.P.

    2017-01-01

    Trace elements term defines the presence of low concentrations metals at environment. Some of them are considered biologically essential, as Co, Cu and Mn. Others can cause detriment to environment and human health, as Pb, Cd, Hg, As, Ti and U. A large number of them have radioactive isotopes, implying the evaluation of risks for human health should be done considering the precepts of environmental radiological protection. The ecosystem pollution with trace elements generates changes at the geochemistry cycle of these elements and in environmental quality. Soils have single characteristics when compared with another components of biosphere (air, water and biota), cause they introduce themselves not only as a drain towards contaminants, but also as natural buffer that control the transport of chemical elements and other substances for atmosphere, hydrosphere and biota. The main purpose of environmental monitoring program is to evaluate the levels of contaminants in the various compartments of the environment: natural or anthropogenic, and to assess the contribution of a potential contaminant source on the environment. Elemental Composition for the collected samples was determined by inductively coupled plasma mass spectroscopy. The main objective of this work was to evaluate the map baseline of concentration of interest trace elements in environmental samples of water, sediment and soil from Environmental Monitoring Program of Instituto de Radioprotecao e Dosimetria (IRD). The samples were analyzed using an inductively coupled plasma mass spectrometer (ICP-MS) at IRD. >From the knowledge of trace elements concentrations, could be evaluated the environmental quality parameters at the studied ecosystems. The data allowed evaluating some relevant aspects of the study of trace elements in soil and aquatic systems, with emphasis at the distribution, concentration and identification of main anthropic sources of contamination at environment. (author)

  7. Singular traces theory and applications

    CERN Document Server

    Sukochev, Fedor; Zanin, Dmitriy

    2012-01-01

    This text is the first complete study and monograph dedicated to singular traces. For mathematical readers the text offers, due to Nigel Kalton's contribution, a complete theory of traces on symmetrically normed ideals of compact operators. For mathematical physicists and other users of Connes' noncommutative geometry the text offers a complete reference to Dixmier traces and the deeper mathematical features of singular traces. An application section explores the consequences of these features, which previously were not discussed in general texts on noncommutative geometry.

  8. Mass spectrometry in clinical chemistry

    International Nuclear Information System (INIS)

    Pettersen, J.E.

    1977-01-01

    A brief description is given of the functional elements of a mass spectrometer and of some currently employed mass spectrometric techniques, such as combined gas chromatography-mass spectrometry, mass chromatography, and selected ion monitoring. Various areas of application of mass spectrometry in clinical chemistry are discussed, such as inborn errors of metabolism and other metabolic disorders, intoxications, quantitative determinations of drugs, hormones, gases, and trace elements, and the use of isotope dilution mass spectrometry as a definitive method for the establishment of true values for concentrations of various compounds in reference sera. It is concluded that mass spectrometry is of great value in clinical chemistry. (Auth.)

  9. Tracing Actual Causes

    Science.gov (United States)

    2016-08-08

    was articu- lated by David Lewis in his work on causal ex- planations [Lewis, 1986a]. We address the prob- lem by defining the causal history of the...of actual causation involve coun- terfactuals. The counterfactual tradition goes back to Hume [ Hume , 1748] whose position was that an event c is a...work We present a new take on the old problem of tracing ac- tual causes articulated by David Lewis in his work on causal explanations [Lewis, 1986a]. We

  10. On Trace Zero Matrices

    Indian Academy of Sciences (India)

    In this note, we shall try to present an elemen- tary proof of a couple of closely related results which have both proved quite useful, and al~ indicate possible generalisations. The results we have in mind are the following facts: (a) A complex n x n matrix A has trace 0 if and only if it is expressible in the form A = PQ - Q P.

  11. Anisotropic ray trace

    Science.gov (United States)

    Lam, Wai Sze Tiffany

    Optical components made of anisotropic materials, such as crystal polarizers and crystal waveplates, are widely used in many complex optical system, such as display systems, microlithography, biomedical imaging and many other optical systems, and induce more complex aberrations than optical components made of isotropic materials. The goal of this dissertation is to accurately simulate the performance of optical systems with anisotropic materials using polarization ray trace. This work extends the polarization ray tracing calculus to incorporate ray tracing through anisotropic materials, including uniaxial, biaxial and optically active materials. The 3D polarization ray tracing calculus is an invaluable tool for analyzing polarization properties of an optical system. The 3x3 polarization ray tracing P matrix developed for anisotropic ray trace assists tracking the 3D polarization transformations along a ray path with series of surfaces in an optical system. To better represent the anisotropic light-matter interactions, the definition of the P matrix is generalized to incorporate not only the polarization change at a refraction/reflection interface, but also the induced optical phase accumulation as light propagates through the anisotropic medium. This enables realistic modeling of crystalline polarization elements, such as crystal waveplates and crystal polarizers. The wavefront and polarization aberrations of these anisotropic components are more complex than those of isotropic optical components and can be evaluated from the resultant P matrix for each eigen-wavefront as well as for the overall image. One incident ray refracting or reflecting into an anisotropic medium produces two eigenpolarizations or eigenmodes propagating in different directions. The associated ray parameters of these modes necessary for the anisotropic ray trace are described in Chapter 2. The algorithms to calculate the P matrix from these ray parameters are described in Chapter 3 for

  12. Tracers and tracing methods

    International Nuclear Information System (INIS)

    Leclerc, J.P.

    2001-01-01

    The first international congress on 'Tracers and tracing methods' took place in Nancy in May 2001. The objective of this second congress was to present the current status and trends on tracing methods and their applications. It has given the opportunity to people from different fields to exchange scientific information and knowledge about tracer methodologies and applications. The target participants were the researchers, engineers and technologists of various industrial and research sectors: chemical engineering, environment, food engineering, bio-engineering, geology, hydrology, civil engineering, iron and steel production... Two sessions have been planned to cover both fundamental and industrial aspects: 1)fundamental development (tomography, tracer camera visualization and particles tracking; validation of computational fluid dynamics simulations by tracer experiments and numerical residence time distribution; new tracers and detectors or improvement and development of existing tracing methods; data treatments and modeling; reactive tracer experiments and interpretation) 2)industrial applications (geology, hydrogeology and oil field applications; civil engineering, mineral engineering and metallurgy applications; chemical engineering; environment; food engineering and bio-engineering). The program included 5 plenary lectures, 23 oral communications and around 50 posters. Only 9 presentations are interested for the INIS database

  13. A new AMS with RFQ LINAC for trace elements

    International Nuclear Information System (INIS)

    Ueda, Shintaro; Hattori, Toshiyuki; Hayashizaki, Noriyosu; Hata, Toshiki; Kawasaki, Katunori

    2004-01-01

    Accelerator Mass Spectrometry (AMS) is able to measure abundance ratio of the radioisotope, and measurable limit is about 1 x 10 -15 (ppq). Measurable limit is very excellent comparison with other analyzers for trace element. Therefore we have studied a new AMS for trace element. Our system is combined LINAC with a multivalent ion source. The features of new system are following: trace elemental analyses by detect energy of particles, and miniaturization of the system. We are going to report a condition of study. (author)

  14. The method for on-site determination of trace concentrations of methyl mercaptan and dimethyl sulfide in air using a mobile mass spectrometer with atmospheric pressure chemical ionization, combined with a fast enrichment/separation system.

    Science.gov (United States)

    Kudryavtsev, Andrey S; Makas, Alexey L; Troshkov, Mikhail L; Grachev, Mikhail А; Pod'yachev, Sergey P

    2014-06-01

    A method for fast simultaneous on-site determination of methyl mercaptan and dimethyl sulfide in air was developed. The target compounds were actively collected on silica gel, followed by direct flash thermal desorption, fast separation on a short chromatographic column and detection by means of mass spectrometer with atmospheric pressure chemical ionization. During the sampling of ambient air, water vapor was removed with a Nafion selective membrane. A compact mass spectrometer prototype, which was designed earlier at Trofimuk Institute of Petroleum Geology and Geophysics, was used. The minimization of gas load of the atmospheric pressure ion source allowed reducing the power requirements and size of the vacuum system and increasing its ruggedness. The measurement cycle is about 3 min. Detection limits in a 0.6 L sample are 1 ppb for methyl mercaptan and 0.2 ppb for dimethyl sulfide. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. The development and application of mass spectrometry methods for trace-, ultratrace-, isotope- and surface analysis for research tasks of the Juelich Research Centre; Entwicklung und Anwendung massenspektrometrischer Methoden zur Spuren-, Ultraspuren-, Isotopen- und Oberflaechenanalytik fuer Forschungsaufgaben des Forschungszentrums Juelich

    Energy Technology Data Exchange (ETDEWEB)

    Becker, J.S. [ed.; Dietze, H.J. [ed.

    1996-08-01

    This volume contains 15 reports of results of the Central Department for Chemical Analysis of the Juelich Research Centre in the field of mass spectrometry methods of analysis. The individual contributions are (selection): Analysis of GaAs using a combined rf glow discharge and inductively coupled plasma source mass spectrometer; development of an rf GDMS technique for depth profiling analysis of thick Ni- and Co-doped oxide layers on Cr-based alloys of the interconnector of a solid oxide fuel cell; analysis of ceramic layers of high temperature fuel cell by means of LA-IC P-MS; MCS-SIMS studies concerning the effect of Y surface modification on the oxidation behaviour of Cr based ODS alloys; quantitative SIMS analysis on ecbium-doped components of integrated optics; the use of SIMS in process development of high resistance in P buffer layers by means of metal organic gas phase epitaxy; ultratrace and isotope analysis of uranium by means of sector field ICP mass spectrometry; determining of long life radionuclides by means of sector field ICP mass spectrometry; lithium analysis by means of ICP-MS in connection with investigations on the transport of lithium in groundwater. 8 separate abstracts were prepared. (orig./MM) [Deutsch] Dieser Band enthaelt 15 Ergebnisberichte der Zentralabteilung fuer chemische Analysen des Forschungszentrums Juelich auf dem Gebiet der massenspektrometrischen Analysenmethoden. Die einzelnen Beitraege sind (Auswahl): Analysis of GaAs using a Combined rf Glow Discharge and Inductively Coupled Plasma Source Mass Spectrometer; Development of an rf GDMS technique for depth profiling analysis of thick Ni- and Co-doped oxide layers on Cr-based alloys of the interconnector of a solid oxide fuel cell; Analyse von keramischen Schichten der Hochtemperatur-Brennstoffzelle mittels LA-ICP-MS; MCs{sup +}-SIMS-Studies Concerning the Effect of Y-Surface Modification on the Oxidation Behaviour of Cr-Based ODS Alloys; Quantitative SIMS-Analytik an Erbium

  16. Developed determination method of ultra trace elements and ultra trace element levels in plasma of rat fed low magnesium diet.

    Science.gov (United States)

    Kimura, Mieko; Honda, Kazuto; Takeda, Atsuko; Imanishi, Masayo; Takeda, Takahisa

    2004-12-01

    Homeostatic mechanisms keep plasma mineral concentrations largely unchangeable, and are not always reflective of the nutritional status. For that reason, nutritional assessment is difficult and another biological index may be of value. Recently, improvement of measuring instruments has permitted more accurate measurement of trace and ultra trace elements. A new determination method for trace and ultra trace elements in rat plasma, that uses an inductively coupled plasma mass spectrometry (ICP-MS Elan-6000, Perkin Elmer, Co., USA) without pre-treatment has enabled study of basic data of ultra trace element concentrations for the first time. The effect of low magnesium (Mg) intake, as compared with the effect of a normal diet, status of 10 trace and ultra trace element status was studied in 12 young male Wistar rats (3-weeks-old), divided into two groups and fed a normal diet or low Mg diet for 4 weeks. The plasma was diluted with ultra pure water (TAMAPURE-AA: Tama Chemical Co., Japan). Ten trace and ultra trace element (As: 75, Se: 82, Rb: 85, Sr: 87, Mo: 95, Ba: 137, Ta: 181, Ir: 193, Au: 197, Pb: 208) concentrations in the plasma were measured with ICP-MS Elan 6000. As, Rb, Sr, Ta, Ir and Au concentrations were significantly high in the plasma of low Mg rats, compared to levels in rats fed normal diets. Essentiality for mammals has been certified for Se, Rb, Mo, As and Pb, but not yet for Sr, Ba, Au, Ir and Ta. These results prove that trace and ultra trace element concentrations in plasma are changeable by nutritional conditions, and suggest that new physiological functions may be found for these elements, and that they may be proved to be essential for mammals.

  17. Queer Tracings of Genre

    DEFF Research Database (Denmark)

    Balle, Søren Hattesen

    A prominent feature of John Ashbery's debut collection Some Trees is the near ubiquity of classical and post-classical genre designations attached as titles to its poems. Among them appear titles such as "Eclogue", "Sonnet", "Meditations of a Parrot", and "A Pastoral". Neither does Ashbery hesitate...... as (re)tracings of genres that appear somehow residual or defunct in a post-modernist poetic context. On the other, they are made to "encode new [and queer, shb] meanings" (Anne Ferry) inasmuch as Ashbery, for instance, doubles and literalizes Dante's false etymology of the word ‘eclogue' (aig- and logos...

  18. Trace conditioning in insects—keep the trace!

    Science.gov (United States)

    Dylla, Kristina V.; Galili, Dana S.; Szyszka, Paul; Lüdke, Alja

    2013-01-01

    Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS) and an unconditioned stimulus (US) following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination—a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase (Rut-AC), which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning. PMID:23986710

  19. Trace conditioning in insects-keep the trace!

    Science.gov (United States)

    Dylla, Kristina V; Galili, Dana S; Szyszka, Paul; Lüdke, Alja

    2013-01-01

    Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS) and an unconditioned stimulus (US) following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination-a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase (Rut-AC), which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

  20. Trace conditioning in insects – Keep the trace!

    Directory of Open Access Journals (Sweden)

    Kristina V Dylla

    2013-08-01

    Full Text Available Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS and an unconditioned stimulus (US following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination – a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase, which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

  1. Analytical capabilities of high performance liquid chromatography - Atmospheric pressure photoionization - Orbitrap mass spectrometry (HPLC-APPI-Orbitrap-MS) for the trace determination of novel and emerging flame retardants in fish.

    Science.gov (United States)

    Zacs, D; Bartkevics, V

    2015-10-22

    A new analytical method was established and validated for the analysis of 27 brominated flame retardants (BFRs), including so called "emerging" and "novel" BFRs (EBFRs and NBFRs) in fish samples. High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing atmospheric pressure photoionization (APPI) interface operated in negative mode was used for the identification/quantitation of contaminants. HPLC-Orbitrap-MS analysis provided a fast separation of selected analytes within 14 min, thus demonstrating a high throughput processing of samples. The developed methodology was tested by intralaboratory validation in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ), and where possible, trueness was verified by analysis of certified reference materials (CRMs). Recoveries of analytes were between 80 and 119%, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 1.2 to 15.5%. The measured values for both analyzed CRMs agreed with the provided consensus values, revealing the recovery of reference concentrations in 72-119% range. The elaborated method met the sensitivity criterion according to Commission Recommendation 2014/118/EU on monitoring of BFRs in food products for majority of the compounds. The concentrations of polybrominated diphenyl ethers (PBDEs) in real samples determined by HPLC-APPI-Orbitrap-MS method and validated gas chromatography-high-resolution mass spectrometry (GC-HRMS) method were found to be in a good agreement. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Traces generating what was there

    CERN Document Server

    2017-01-01

    Traces keep time contained and make visible what was there. Going back to the art of trace-reading, they continue to be a fundamental resource for scientific knowledge production. The contributions study, from the biology laboratory to the large colliders of particle physics, techniques involved in the production of material traces. Following their changes over two centuries, this collection shows the continuities they have in the digital age.

  3. Lidar Detection of Explosives Traces

    Directory of Open Access Journals (Sweden)

    Bobrovnikov Sergei M.

    2016-01-01

    Full Text Available The possibility of remote detection of traces of explosives using laser fragmentation/laser-induced fluorescence (LF/LIF is studied. Experimental data on the remote visualization of traces of trinitrotoluene (TNT, hexogen (RDX, trotyl-hexogen (Comp B, octogen (HMX, and tetryl with a scanning lidar detector of traces of nitrogen-containing explosives at a distance of 5 m are presented.

  4. Trace anomaly and counterterms in designer gravity

    Energy Technology Data Exchange (ETDEWEB)

    Anabalón, Andrés [Departamento de Ciencias, Facultad de Artes Liberalesand Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Av. Padre Hurtado 750, Viña del Mar (Chile); Astefanesei, Dumitru [Instituto de Física, Pontificia Universidad Católica de Valparaíso,Casilla 4059, Valparaíso (Chile); Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,14476 Golm (Germany); Choque, David [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,14476 Golm (Germany); Universidad Técnica Federico Santa María,Av. España 1680, Valparaíso (Chile); Martínez, Cristián [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile)

    2016-03-17

    We construct concrete counterterms of the Balasubramanian-Kraus type for Einstein-scalar theories with designer gravity boundary conditions in AdS{sub 4}, so that the total action is finite on-shell and satisfy a well defined variational principle. We focus on scalar fields with the conformal mass m{sup 2}=−2l{sup −2} and show that the holographic mass matches the Hamiltonian mass for any boundary conditions. We compute the trace anomaly of the dual field theory in the generic case, as well as when there exist logarithmic branches of non-linear origin. As expected, the anomaly vanishes for the boundary conditions that are AdS invariant. When the anomaly does not vanish, the dual stress tensor describes a thermal gas with an equation of state related to the boundary conditions of the scalar field. In the case of a vanishing anomaly, we recover the dual theory of a massless thermal gas. As an application of the formalism, we consider a general family of exact hairy black hole solutions that, for some particular values of the parameters in the moduli potential, contains solutions of four-dimensional gauged N=8 supergravity and its ω-deformation. Using the AdS/CFT duality dictionary, they correspond to triple trace deformations of the dual field theory.

  5. Assessment of TRACE code against CHF experiments

    International Nuclear Information System (INIS)

    Audrius Jasiulevicius; Rafael Macian-Juan; Paul Coddington

    2005-01-01

    Full text of publication follows: This paper reports on the validation of the USNRC 'consolidate' code TRACE with data obtained during Critical Heat Flux (CHF) experiments in single channels and round and annular tubes. CHF is one of the key reactor safety parameters, because it determines the conditions for the onset of transition boiling in the core rod bundles, leading to the low heat transfer rates characteristics of the post-CHF heat transfer regime. In the context of the participation of PSI in the the International Programme for uncertainty analysis BEMUSE, we have carried out extensive work for the validation of some important TRACE models. The present work is aimed at assessing the range of validity for the CHF correlations and post-CHF heat transfer models currently included in TRACE. The heat transfer experiments selected for the assessment were performed at the Royal Institute of Technology (RIT) in Stockholm, Sweden and at the Atomic Energy Establishment in Winfrith, UK. The experimental investigations of the CHF and post-CHF heat transfer at RIT for flow of water in vertical tubes and annulus were performed at pressures ranging from 1 to 20 MPa and coolant mass fluxes from 500 to 3000 kg/m 2 s. The liquid was subcooled by 10 deg. C and 40 deg. C at the inlet of the test section. The experiments were performed on two different types of test sections. Experiments with uniformly heated single 7.0 m long tubes were carried out with three different inner tube diameters of 10, 14.9 and 24.7 mm. A series of experiments with non-uniform axial power distribution were also conducted in order to study the effect of the axial heat flux distribution on the CHF conditions in both 7.0 m long single tubes and 3.65 long annulus. Several different axial power profiles were employed with bottom, middle and top power peaks as well as the double-humped axial power profiles. In total more than 100 experiments with uniform axial heat flux distribution and several hundreds

  6. Trace analysis of semiconductor materials

    CERN Document Server

    Cali, J Paul; Gordon, L

    1964-01-01

    Trace Analysis of Semiconductor Materials is a guidebook concerned with procedures of ultra-trace analysis. This book discusses six distinct techniques of trace analysis. These techniques are the most common and can be applied to various problems compared to other methods. Each of the four chapters basically includes an introduction to the principles and general statements. The theoretical basis for the technique involved is then briefly discussed. Practical applications of the techniques and the different instrumentations are explained. Then, the applications to trace analysis as pertaining

  7. Trace Mineral Losses in Sweat

    National Research Council Canada - National Science Library

    Chinevere, Troy D; McClung, James P; Cheuvront, Samuel N

    2007-01-01

    Copper, iron and zinc are nutritionally essential trace minerals that confer vital biological roles including the maintenance of cell structure and integrity, regulation of metabolism, immune function...

  8. Determination of trace elements in high pure rare earth oxide by double focusing inductively coupled plasma mass spectrometry (HR ICP-MS) and high performance liquid chromatography (HPLC) techniques

    International Nuclear Information System (INIS)

    Pedreira Filho, Walter dos Reis

    2000-01-01

    Rare earth oxides are used in several technological fields whose applications can be observed in several areas of modern technology, among which are included: lasers, semiconductors semi, high purity materials and metallic alloys. The field of applications of the rare earth elements is quite wide. Several important industrial applications are ceramics, catalysts and metallurgical as well as research areas and high technology sectors. Such applications have been presenting an accentuated growth in the last years. Chemical characterization of rare earth oxides of high purity has been constituting one of the major challenges of analytical chemistry. Several analytical techniques were used for chemical characterization of high purity rare earth the oxides. Even so, those techniques present limitations when one needs to characterize materials of a high level of purity, as in the case of rare earth oxides. Some of those limitations are associated, for example, to spectral interference. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a powerful analytical tool for quantitative analysis of metal impurities in high purity materials. The Instituto de Pesquisas Energeticas e Nucleares (IPEN) has an unit of production and purification of rare earth oxides, with above 99,9% level of purity. In this work, the rare earth impurities were characterized in samples (La 2 O 3 ; CeO 2 ; Pr 6 O 11 ; Nd 2 O 3 ; Sm 2 O 3 ; Gd 2 O 3 ; Y 2 O 3 ) produced at the IPEN and certified standard materials produced by Johnson Matthey Chemical (JMC). The technique of high performance liquid chromatography (HPLC) was used in the separation of the impurities. Quantification of metallic impurities was carried out as inductively coupled plasma mass spectrometer (HR-ICP MS). In this work it is presented a new analytical methodology in the chemical characterization of metallic impurities in rare earth oxides of high purity (> 99,9%) with and without separation of the matrix. Analyses of standard

  9. Tracing Cultural Memory

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    to Soweto’s Regina Mundi Church, this thesis analyses tourists’ snapshots at sites of memory and outlines their tracing activity in cultural memory. It draws on central concepts of actor - network theory and visual culture studies for a cross - disciplinary methodology to comprehend the collective...... of memory. They highlight the role of mundane uses of the past and indicate the need for cross - disciplinary research on the visual and on memory......We encounter, relate to and make use of our past and that of others in multifarious and increasingly mobile ways. Tourism is one of the main paths for encountering sites of memory. This thesis examines tourists’ creative appropriations of sites of memory – the objects and future memories inspired...

  10. Ultra-trace levels analysis of microcystins and nodularin in surface water by on-line solid-phase extraction with high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Balest, Lydia; Murgolo, Sapia; Sciancalepore, Lucia; Montemurro, Patrizia; Abis, Pier Paolo; Pastore, Carlo; Mascolo, Giuseppe

    2016-06-01

    An on-line solid phase extraction coupled with high-performance liquid chromatography in tandem with mass spectrometry (on-line SPE/HPLC/MS-MS) method for the determination of five microcystins and nodularin in surface waters at submicrogram per liter concentrations has been optimized. Maximum recoveries were achieved by carefully optimizing the extraction sample volume, loading solvent, wash solvent, and pH of the sample. The developed method was also validated according to both UNI EN ISO IEC 17025 and UNICHIM guidelines. Specifically, ten analytical runs were performed at three different concentration levels using a reference mix solution containing the six analytes. The method was applied for monitoring the concentrations of microcystins and nodularin in real surface water during a sampling campaign of 9 months in which the ELISA method was used as standard official method. The results of the two methods were compared showing good agreement when the highest concentration values of MCs were found. Graphical abstract An on-line SPE/HPLC/MS-MS method for the determination of five microcystins and nodularin in surface waters at sub μg L(-1) was optimized and compared with ELISA assay method for real samples.

  11. Trace determination of organophosphate esters in white wine, red wine, and beer samples using dispersive liquid-liquid microextraction combined with ultra-high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Pang, Long; Yang, Huiqiang; Yang, Peijie; Zhang, Hongzhong; Zhao, Jihong

    2017-08-15

    In this study, dispersive liquid-liquid microextraction coupled with ultra-high-performance liquid chromatography-tandem mass spectrometry was developed for the analysis of five representative organophosphate esters (OPEs) in wine samples. Under optimized conditions, the proposed method resulted in good linearity (R 2 >0.9933) over the range of 0.1-100μgL -1 , with limits of detection (LODs, S/N =3) and quantification (LOQs, S/N =10) in the ranges of 0.48-18.8ngL -1 and 1.58-62.5ngL -1 , respectively. Inter- and intra-assay precisions of RSD% ranged from 3.21% to 6.13% and from 1.69% to 7.63%, respectively. The spiked recoveries of target OPEs from white wine, red wine, and beer samples were in the ranges of 80-122%, 76-120%, and 76-110%, respectively, at two different concentration levels. The total concentrations of five OPEs found in white wine, red wine, and beer samples were in the ranges of 0.29-0.85μgL -1 , 1.00-3.05μgL -1 , and 0.86-1.47μgL -1 , respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Trace determination of antibacterial pharmaceuticals in fishes by microwave-assisted extraction and solid-phase purification combined with dispersive liquid-liquid microextraction followed by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Huang, Peiting; Zhao, Pan; Dai, Xinpeng; Hou, Xiaohong; Zhao, Longshan; Liang, Ning

    2016-02-01

    A novel pretreatment method involving microwave-assisted extraction and solid-phase purification combined with dispersive liquid-liquid microextraction (MAE-SPP-DLLME) followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was established for the simultaneous determination of six antibacterial pharmaceuticals including metronidazole, tinidazole, chloramphenicol, thiamphenicol, malachite green and crystal violet. The conditions of MAE were optimized using an orthogonal design and the optimal conditions were found to be 8mL for acetonitrile, 50°C for 5min. Then, neutral alumina column was employed in the solid-phase purification. Finally, the critical parameters affecting DLLME, including selection of extraction and dispersive solvent, adjustment of pH, salt concentration, extraction time, were investigated by single factor study. Under optimum conditions, good linearities (r>0.9991) and satisfied recoveries (Recoveries>87.0%, relative standard deviation (RSD)extraction followed by purification. The established method was sensitive, rapid, accurate and employable to simultaneously determine target analytes in farmed fish, river fish and marine fish. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Solid-phase extraction in combination with dispersive liquid-liquid microextraction and ultra-high performance liquid chromatography-tandem mass spectrometry analysis: the ultra-trace determination of 10 antibiotics in water samples.

    Science.gov (United States)

    Liang, Ning; Huang, Peiting; Hou, Xiaohong; Li, Zhen; Tao, Lei; Zhao, Longshan

    2016-02-01

    A novel method, solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME), was developed for ultra-preconcentration of 10 antibiotics in different environmental water samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry detection. The optimized results were obtained as follows: after being adjusted to pH 4.0, the water sample was firstly passed through PEP-2 column at 10 mL min(-1), and then methanol was used to elute the target analytes for the following steps. Dichloromethane was selected as extraction solvent, and methanol/acetonitrile (1:1, v/v) as dispersive solvent. Under optimal conditions, the calibration curves were linear in the range of 1-1000 ng mL(-1) (sulfamethoxazole, cefuroxime axetil), 5-1000 ng mL(-1) (tinidazole), 10-1000 ng mL(-1) (chloramphenicol), 2-1000 ng mL(-1) (levofloxacin oxytetracycline, doxycycline, tetracycline, and ciprofloxacin) and 1-400 ng mL(-1) (sulfadiazine) with a good precision. The LOD and LOQ of the method were at very low levels, below 1.67 and 5.57 ng mL(-1), respectively. The relative recoveries of the target analytes were in the range from 64.16% to 99.80% with relative standard deviations between 0.7 and 8.4%. The matrix effect of this method showed a great decrease compared with solid-phase extraction and a significant value of enrichment factor (EF) compared with dispersive liquid-liquid microextraction. The developed method was successfully applied to the extraction and analysis of antibiotics in different water samples with satisfactory results.

  14. Trace Elements in Teeth by ICPMS

    International Nuclear Information System (INIS)

    Zahran, N.F.; Helal, A.I.; Amr, M.A.; Amr, M.A.; Al-saad, K.A.

    2008-01-01

    Teeth are reported to be suitable indicators of trace element exposure from environment and nutritional status. Inductively coupled plasma mass spectrometry (ICP-MS) is used to compare the trace element content of children's primary teeth and adult teeth. Primary teeth are collected from 28 children and 42 adult from non-industrial City. The data are assessed statistically using t-tests. The adult teeth contained significantly greater concentrations of Na, Mg, Al, Fe, Ni, Cu, Sr, Cd, Ba, Pb and U and significantly less Mn, Co, As, Se, Mo and Bi than the children teeth. Additional measurements on adult teeth pulps are performed. Comparison between trace element concentrations in health and caries teeth pulps show that the mean concentrations of Na, Al, K, Cr, Mn, Co, Cu, Zn, Mo, Ag, Bi and U are lower in caries than healthy teeth pulps. On the other hand, the mean concentrations of Mg, Cd and Pb are higher in caries samples than healthy teeth pulps

  15. Digital Traces of Information Systems

    DEFF Research Database (Denmark)

    Hedman, Jonas; Srinivasan, Nikhil; Lindgren, Rikard

    2013-01-01

    In this paper, we point to the potential and implications of digital traces as novel data source in the study of contemporary activities and behaviors. We do this to raise awareness of IS researchers of such traces in increasingly complex sociomaterial practices. We develop a two-dimensional fram...

  16. Magnetic solutions in AdS 5 and trace anomalies

    Science.gov (United States)

    Brihaye, Yves; Radu, Eugen

    2008-01-01

    We discuss black hole and black string solutions in d = 5 Einstein-Yang-Mills theory with negative cosmological constant, proposing a method to compute their mass and action. The magnetic gauge field of these configurations does not vanish at infinity. We argue that this implies a nonvanishing trace for the stress tensor of the dual d = 4 theory.

  17. Heat kernel for Newton-Cartan trace anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Auzzi, Roberto [Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Via Musei 41, Brescia, 25121 (Italy); INFN Sezione di Perugia, Via A. Pascoli, Perugia, 06123 (Italy); Nardelli, Giuseppe [Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Via Musei 41, Brescia, 25121 (Italy); TIFPA - INFN, Università di Trento,c/o Dipartimento di Fisica, Povo, TN, 38123 (Italy)

    2016-07-11

    We compute the leading part of the trace anomaly for a free non-relativistic scalar in 2+1 dimensions coupled to a background Newton-Cartan metric. The anomaly is proportional to 1/m, where m is the mass of the scalar. We comment on the implications of a conjectured a-theorem for non-relativistic theories with boost invariance.

  18. Tracing Geothermal Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Michael C. Adams; Greg Nash

    2004-03-01

    Geothermal water must be injected back into the reservoir after it has been used for power production. Injection is critical in maximizing the power production and lifetime of the reservoir. To use injectate effectively the direction and velocity of the injected water must be known or inferred. This information can be obtained by using chemical tracers to track the subsurface flow paths of the injected fluid. Tracers are chemical compounds that are added to the water as it is injected back into the reservoir. The hot production water is monitored for the presence of this tracer using the most sensitive analytic methods that are economically feasible. The amount and concentration pattern of the tracer revealed by this monitoring can be used to evaluate how effective the injection strategy is. However, the tracers must have properties that suite the environment that they will be used in. This requires careful consideration and testing of the tracer properties. In previous and parallel investigations we have developed tracers that are suitable from tracing liquid water. In this investigation, we developed tracers that can be used for steam and mixed water/steam environments. This work will improve the efficiency of injection management in geothermal fields, lowering the cost of energy production and increasing the power output of these systems.

  19. Trace-metal distributions in seawater and anoxic brines in the eastern Mediterranean Sea

    NARCIS (Netherlands)

    Saager, Paul M.; Schijf, Johan; Baar, Hein J.W. de; Millero, F.J.

    1993-01-01

    The vertical distribution of dissolved and particulate trace metals (Mn, Fe, Ni, Cu, Cd) is reported for seawater and the anoxic brines of Tyro and Bannock Basins in the eastern Mediterranean. In normal Mediterranean seawater, the distribution of dissolved trace metals is governed by water mass

  20. Atomic mass spectrometry

    International Nuclear Information System (INIS)

    Sanz-Medel, A.

    1997-01-01

    The elemental inorganic analysis seems to be dominated today by techniques based on atomic spectrometry. After an evaluation of advantages and limitations of using mass analysers (ion detectors) versus conventional photomultipliers (photon detector) a brief review of the more popular techniques of the emerging Atomic Mass spectrometry is carried out. Their huge potential for inorganic trace analysis is such that in the future we could well witness how this end of the century and millennium marked the fall of the photons empire in Analytical Atomic Spectrometry. (Author)

  1. Trace formulae for arithmetical systems

    International Nuclear Information System (INIS)

    Bogomolny, E.B.; Georgeot, B.; Giannoni, M.J.; Schmit, C.

    1992-09-01

    For quantum problems on the pseudo-sphere generated by arithmetic groups there exist special trace formulae, called trace formulae for Hecke operators, which permit the reconstruction of wave functions from the knowledge of periodic orbits. After a short discussion of this subject, the Hecke operators trace formulae are presented for the Dirichlet problem on the modular billiard, which is a prototype of arithmetical systems. The results of numerical computations for these semiclassical type relations are in good agreement with the directly computed eigenfunctions. (author) 23 refs.; 2 figs

  2. Rapid trace detection of triacetone triperoxide (TATP) by complexation reactions during desorption electrospray ionization.

    Science.gov (United States)

    Cotte-Rodríguez, Ismael; Chen, Hao; Cooks, R Graham

    2006-03-07

    Desorption electrospray ionization (DESI) mass spectrometry is used for rapid, specific and sensitive detection of trace amounts of the notorious explosive TATP present on ambient surfaces by alkali metal complexation in a simple spray technique.

  3. Ultra-trace Measurements in the WAIS Divide 06A Ice Core, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — These data contain the results of gas chromatography mass spectrometry (GC-MS) analysis of 207 samples from the WAIS Divide 06A ice core. The trace gases found in...

  4. Traces Synchronization in Distributed Networks

    Directory of Open Access Journals (Sweden)

    Eric Clément

    2009-01-01

    Full Text Available This article proposes a novel approach to synchronize a posteriori the detailed execution traces from several networked computers. It can be used to debug and investigate complex performance problems in systems where several computers exchange information. When the distributed system is under study, detailed execution traces are generated locally on each system using an efficient and accurate system level tracer, LTTng. When the tracing is finished, the individual traces are collected and analysed together. The messaging events in all the traces are then identified and correlated in order to estimate the time offset over time between each node. The time offset computation imprecision, associated with asymmetric network delays and operating system latency in message sending and receiving, is amortized over a large time interval through a linear least square fit over several messages covering a large time span. The resulting accuracy is such that it is possible to estimate the clock offsets in a distributed system, even with a relatively low volume of messages exchanged, to within the order of a microsecond while having a very low impact on the system execution, which is sufficient to properly order the events traced on the individual computers in the distributed system.

  5. A Theory of Network Tracing

    Science.gov (United States)

    Acharya, Hrishikesh B.; Gouda, Mohamed G.

    Traceroute is a widely used program for computing the topology of any network in the Internet. Using Traceroute, one starts from a node and chooses any other node in the network. Traceroute obtains the sequence of nodes that occur between these two nodes, as specified by the routing tables in these nodes. Each use of Traceroute in a network produces a trace of nodes that constitute a simple path in this network. In every trace that is produced by Traceroute, each node occurs either by its unique identifier, or by the anonymous identifier"*". In this paper, we introduce the first theory aimed at answering the following important question. Is there an algorithm to compute the topology of a network N from a trace set T that is produced by using Traceroute in network N, assuming that each edge in N occurs in at least one trace in T, and that each node in N occurs by its unique identifier in at least one trace in T? We prove that the answer to this question is "No" if N is an even ring or a general network. However, it is "Yes" if N is a tree or an odd ring. The answer is also "No" if N is mostly-regular, but "Yes" if N is a mostly-regular even ring.

  6. Tracing the cosmic web

    Science.gov (United States)

    Libeskind, Noam I.; van de Weygaert, Rien; Cautun, Marius; Falck, Bridget; Tempel, Elmo; Abel, Tom; Alpaslan, Mehmet; Aragón-Calvo, Miguel A.; Forero-Romero, Jaime E.; Gonzalez, Roberto; Gottlöber, Stefan; Hahn, Oliver; Hellwing, Wojciech A.; Hoffman, Yehuda; Jones, Bernard J. T.; Kitaura, Francisco; Knebe, Alexander; Manti, Serena; Neyrinck, Mark; Nuza, Sebastián E.; Padilla, Nelson; Platen, Erwin; Ramachandra, Nesar; Robotham, Aaron; Saar, Enn; Shandarin, Sergei; Steinmetz, Matthias; Stoica, Radu S.; Sousbie, Thierry; Yepes, Gustavo

    2018-01-01

    The cosmic web is one of the most striking features of the distribution of galaxies and dark matter on the largest scales in the Universe. It is composed of dense regions packed full of galaxies, long filamentary bridges, flattened sheets and vast low-density voids. The study of the cosmic web has focused primarily on the identification of such features, and on understanding the environmental effects on galaxy formation and halo assembly. As such, a variety of different methods have been devised to classify the cosmic web - depending on the data at hand, be it numerical simulations, large sky surveys or other. In this paper, we bring 12 of these methods together and apply them to the same data set in order to understand how they compare. In general, these cosmic-web classifiers have been designed with different cosmological goals in mind, and to study different questions. Therefore, one would not a priori expect agreement between different techniques; however, many of these methods do converge on the identification of specific features. In this paper, we study the agreements and disparities of the different methods. For example, each method finds that knots inhabit higher density regions than filaments, etc. and that voids have the lowest densities. For a given web environment, we find a substantial overlap in the density range assigned by each web classification scheme. We also compare classifications on a halo-by-halo basis; for example, we find that 9 of 12 methods classify around a third of group-mass haloes (i.e. Mhalo ∼ 1013.5 h-1 M⊙) as being in filaments. Lastly, so that any future cosmic-web classification scheme can be compared to the 12 methods used here, we have made all the data used in this paper public.

  7. [Trace elements of bone tumors].

    Science.gov (United States)

    Kalashnikov, V M; Zaĭchik, V E; Bizer, V A

    1983-01-01

    Due to activation analysis involving the use of neutrons from a nuclear reactor, the concentrations of 11 trace elements: scandium, iron, cobalt, mercury, rubidium, selenium, silver, antimony, chrome, zinc and terbium in intact bone and skeletal tumors were measured. 76 specimens of bioptates and resected material of operations for bone tumors and 10 specimens of normal bone tissue obtained in autopsies of cases of sudden death were examined. The concentrations of trace elements and their dispersion patterns in tumor tissue were found to be significantly higher than those in normal bone tissue. Also, the concentrations of some trace elements in tumor differed significantly from those in normal tissue; moreover, they were found to depend on the type and histogenesis of the neoplasm.

  8. Evaluation of trace element status of organic dairy cattle.

    Science.gov (United States)

    Orjales, I; Herrero-Latorre, C; Miranda, M; Rey-Crespo, F; Rodríguez-Bermúdez, R; López-Alonso, M

    2017-11-06

    The present study aimed to evaluate trace mineral status of organic dairy herds in northern Spain and the sources of minerals in different types of feed. Blood samples from organic and conventional dairy cattle and feed samples from the respective farms were analysed by inductively coupled plasma mass spectrometry to determine the concentrations of the essential trace elements (cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), iodine (I), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se) and zinc (Zn)) and toxic trace elements (arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb)). Overall, no differences between organic and conventional farms were detected in serum concentrations of essential and toxic trace elements (except for higher concentrations of Cd on the organic farms), although a high level of inter-farm variation was detected in the organic systems, indicating that organic production greatly depends on the specific local conditions. The dietary concentrations of the essential trace elements I, Cu, Se and Zn were significantly higher in the conventional than in the organic systems, which can be attributed to the high concentration of these minerals in the concentrate feed. No differences in the concentrations of trace minerals were found in the other types of feed. Multivariate chemometric analysis was conducted to determine the contribution of different feed sources to the trace element status of the cattle. Concentrate samples were mainly associated with Co, Cu, I, Se and Zn (i.e. with the elements supplemented in this type of feed). However, pasture and grass silage were associated with soil-derived elements (As, Cr, Fe and Pb) which cattle may thus ingest during grazing.

  9. Trace Invariance for Quaternion Matrices

    Directory of Open Access Journals (Sweden)

    Ralph John de la Cruz

    2015-12-01

    Full Text Available Let F be a f ield. It is a classical result in linear algebra that for each A, P ϵ Mn (F such that P is nonsingular, tr A = tr (PAP-1. We show in this paper that the preceding property does not hold true if F is the division ring of real quaternions. We show that the only quaternion matrices that have their trace invariant under unitary similarity are Hermitian matrices, and that the only matrices that have their trace invariant under similarity are real scalar matrices.

  10. Effective holographic models for QCD: Glueball spectrum and trace anomaly

    Science.gov (United States)

    Ballon-Bayona, Alfonso; Boschi-Filho, Henrique; Mamani, Luis A. H.; Miranda, Alex S.; Zanchin, Vilson T.

    2018-02-01

    We investigate effective holographic models for QCD arising from five-dimensional dilaton gravity. The models are characterized by a dilaton with a mass term in the UV, dual to a CFT deformation by a relevant operator, and quadratic in the IR. The UV constraint leads to the explicit breaking of conformal symmetry, whereas the IR constraint guarantees linear confinement. We propose semianalytic interpolations between the UV and the IR and obtain a spectrum for scalar and tensor glueballs consistent with lattice QCD data. We use the glueball spectrum as a physical constraint to find the evolution of the model parameters as the mass term goes to 0. Finally, we reproduce the universal result for the trace anomaly of deformed CFTs and propose a dictionary between this result and the QCD trace anomaly. A nontrivial consequence of this dictionary is the emergence of a β function similar to the two-loop perturbative QCD result.

  11. Bayesian Contact Tracing for Communicable Respiratory Disease

    Science.gov (United States)

    Shalaby, Ayman; Lizotte, Daniel

    2013-01-01

    Objective The purpose of our work is to develop a system for automatic contact tracing with the goal of identifying individuals who are most likely infected, even if we do not have direct diagnostic information on their health status. Control of the spread of respiratory pathogens (e.g. novel influenza viruses) in the population using vaccination is a challenging problem that requires quick identification of the infectious agent followed by large-scale production and administration of a vaccine. This takes a significant amount of time. A complementary approach to control transmission is contact tracing and quarantining, which are currently applied to sexually transmitted diseases (STDs). For STDs, identifying the contacts that might have led to disease transmission is relatively easy; however, for respiratory pathogens, the contacts that can lead to transmission include a huge number of face-to-face daily social interactions that are impossible to trace manually. Introduction The evolution of novel influenza viruses in humans is a biological phenomenon that can not be stopped. All existing data suggest that vaccination against the morbidity and mortality of the novel influenza viruses is our best line of defence. Unfortunately, vaccination requires that the infectious agent to be quickly identified and a safe vaccine in large quantities is produced and administered. As was witnessed with the 2009 H1N1 influenza pandemic, these steps took a frustratingly long period during which the novel influenza virus continued its unstoppable and rapid global spreading. In addition to the different vaccination strategies (e.g. random mass vaccination, age structured vaccination), isolation and quarantining of infected individuals is another effective method used by the public health agencies to control the spreading of infectious diseases. Isolation is effective against any infectious disease, however it can be very hard to detect infectious individuals in the population when

  12. SPECTROPHOTOMETRIC DETERMINATION OF TRACE OXALIC ...

    African Journals Online (AJOL)

    Based on the property that oxalic acid has the effect on the replacement of dibromochloroarsenazo in zirconium(IV)-dibromochloroarsenazo complex to produce hyperchromic effects in 1.26 M hydrochloric acid medium, a novel method for the determination of trace oxalic acid by spectrophotometry was developed.

  13. Trace elements in brazilian soils

    International Nuclear Information System (INIS)

    Rocha, Geraldo Cesar

    1995-01-01

    A literature revision on trace elements (Zn, B, Mn, Mo, Cu, Fe, and Cl) in Brazilian soils was prepared, with special attention to the chemical form and range in the soil, extraction methods and correlation of the amount in soils with soil properties

  14. Determination of iodine at ppt level in a nitric acid medium by inductively coupled plasma sector field mass spectrometry: influence of the chemical forms; Etude de la determination de traces d'iode en solution par spectrometrie de masse a secteur magnetique utilisant un plasma a couplage inductif comme source d'ionisation: influence de la forme chimique

    Energy Technology Data Exchange (ETDEWEB)

    Langlois, B

    2001-07-01

    Inductively Coupled Plasma Sector Field Mass Spectrometry (ICP/SFMS) was used to determine several chemical forms of iodine, at ppt level, in a nitric acid media. Ascorbic acid was added as a reducing agent in order to maintain iodine as iodide. In a preliminary approach, the influence of the chemical form was studied by comparing inorganic iodine (NaI) and organic iodine (CH3I). Different signal responses were observed. With a conventional sample introduction system, sensitivities obtained for iodo-methane could differ by a factor of 5. This was not caused by a problem of atomization or by a change in the ionization efficiency of the iodo-compound into the plasma. The low volatilization temperature of iodo-methane (315.5 K) seemed to be the main explanation of this phenomena. Actually, nebulization resulted in the volatilization of a 2% nitric acid solution containing iodo-methane. As a result, the transport efficiency of iodo-methane between the nebulizer and the torch was approaching 100%. A Direct Injection High Efficiency Nebulizer (DIHEN) allowed us to minimize the behavior difference between the two iodine species, but the sensitivity ratio was inverted and still differed by 20 - 40%. Moreover, the association of a guard electrode and the direct injection system was studied in order to apply these equipments to the determination of iodine. This association allowed us to improve the sensitivity by a factor of 10 and to minimize memory effects, when compared with a conventional system. Further studies indicated that signal responses obtained with different iodine-containing species, except for iodo-methane, were found to be similar. (author)

  15. Natural wetland emissions of methylated trace elements

    NARCIS (Netherlands)

    Vriens, B.; Lenz, M.; Charlet, L.; Berg, M.; Winkel, L.H.E.

    2014-01-01

    Natural wetlands are well known for their significant methane emissions. However, trace element emissions via biomethylation and subsequent volatilization from pristine wetlands are virtually unstudied, even though wetlands constitute large reservoirs for trace elements. Here we show that the

  16. Trace and ultratrace level elemental and speciation analysis

    International Nuclear Information System (INIS)

    Arunachalam, J.

    2012-01-01

    Accurate determination of elements present at parts per million and billion levels in various matrices is a growing requirement in different fields. In environmental sciences various trace elements need to be analyzed so as establish the dispersal models of pollutants or the adequacy of effluent treatment prior to discharge into water bodies. The issues of bioaccumulation and magnification are important in aquatic systems. In nutrition and biochemistry one has to establish the bio-availability of essential and toxic elemental species as toxic elements prevent assimilation of essential elements. Fission and fusion technologies use a variety of structural materials requiring many trace elements to be present at levels strictly below the specified levels. Ultra-pure bulk semiconductor materials are required for fabrication devices. In metallurgy and materials sciences too, various trace elements are known to influence the properties. In the emerging fields like nanotechnology, it is necessary to understand the passage and accumulation of nano-particles inside the cells, through trace analysis. Many analytical techniques exist which can provide the concentration information in the bulk materials with good accuracy. They include ICP-AES, FAAS, and ICP-MS, which are solution based techniques. Direct solid state analytical techniques are Glow Discharge Mass Spectrometry (GDMS) and XRF. Accelerator based ion-beam analysis techniques can provide information on concentration and depth profiles of different elements in layered structures. Hyphenated techniques such as HPLC/lC-ICPMS, are helpful in identifying various chemical oxidation states in which a given element might be present in a matrix, which is termed as speciation analysis. This presentation will include the existing analytical competencies and the laboratory requirements for trace and ultra trace element elemental and speciation analyses and their applications. (author)

  17. Trace element measurement for assessment of dog food safety.

    Science.gov (United States)

    De Nadai Fernandes, Elisabete A; Elias, Camila; Bacchi, Márcio Arruda; Bode, Peter

    2018-01-01

    The quality of dog diets depends on adequate ingredients capable of providing optimal nutrition and free of contaminants, for promoting long-term health. Trace elements in 95 samples of dry food for dog puppies (n = 32) and adults (n = 63) of various brands were measured using instrumental neutron activation analysis (INAA). The mass fractions of most elements were within the permissible limits for dogs. Aluminum, antimony, and uranium presented fairly high levels in some samples, which may imply health risks. Aluminum mass fractions ranged from brand, super-premium dog food. Antimony mass fractions ranged up to 5.14 mg/kg, with the highest values measured in six samples of dog food from the same producer. The mass fractions of uranium was found up to 4 mg/kg in commercial brands from five different producers.

  18. Distributed trace using central performance counter memory

    Science.gov (United States)

    Satterfield, David L.; Sexton, James C.

    2013-01-22

    A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

  19. Probabilistic Connections for Bidirectional Path Tracing

    OpenAIRE

    Popov, Stefan; Ramamoorthi, Ravi; Durand, Fredo; Drettakis, George

    2015-01-01

    International audience; Bidirectional Path Tracing Probabilistic Connections for Bidirectional Path Tracing Figure 1: Our Probabilistic Connections for Bidirectional Path Tracing approach importance samples connections to an eye sub-path, and greatly reduces variance, by considering and reusing multiple light sub-paths at once. Our approach (right) achieves much higher quality than bidirectional path-tracing on the left for the same computation time (~8.4 min).. Abstract Bidirectional path tr...

  20. Tracing Utopia in 'Utopia Station'

    DEFF Research Database (Denmark)

    Schwarzbart, Judith

    Art (Publication due in 2012)). But it seems to differ noticeable from the ideologically driven concept(s) of the 20th century avant-garde. The paper will suggest that we in experiments with openness and structure, with an ambivalent engagement in popular culture and everyday life, and complex double...... at the many layers of discourse, ‘thinking-in-process’ and collaboration. These processes led to particular presentational formats (display) and architectural frameworks for activities, and gave way to a variety of other material and situated performative modes of audience encounters. Here, we can trace avant......-garde ideas about radical democracy through open processes and active involvement of audience-participants, we can trace formal (architectural) structures back to the Russian constructivism and many other links back in time, but the central question remains if theses ethical-political and aesthetic gestures...

  1. Requirement Tracing using Term Extraction

    OpenAIRE

    Al-Saati, Najla; Abdul-Jaleel, Raghda

    2015-01-01

    Requirements traceability is an essential step in ensuring the quality of software during the early stages of its development life cycle. Requirements tracing usually consists of document parsing, candidate link generation and evaluation and traceability analysis. This paper demonstrates the applicability of Statistical Term Extraction metrics to generate candidate links. It is applied and validated using two data sets and four types of filters two for each data set, 0.2 and 0.25 for MODIS, 0...

  2. Trace Amines and Cocaine Abuse

    OpenAIRE

    Li, Jun-Xu

    2014-01-01

    Cocaine addiction remains a clinical challenge with no effective pharmacotherapy available. Trace amine associated receptor (TAAR) 1 represents a promising drug target for the modulation of dopaminergic system and stimulant abuse. This Viewpoint discusses the emerging data which strongly suggest that TAAR 1 functions as a molecular “brake” that controls the addiction-related effects of cocaine and could be a novel drug target for the development of efficacious pharmacothe...

  3. Trace Replay and Network Simulation Tool

    Energy Technology Data Exchange (ETDEWEB)

    2017-09-22

    TraceR Is a trace replay tool built upon the ROSS-based CODES simulation framework. TraceR can be used for predicting network performance and understanding network behavior by simulating messaging In High Performance Computing applications on interconnection networks.

  4. Precambrian biota: protistan origin of trace fossils?

    Science.gov (United States)

    Pawlowski, Jan; Gooday, Andrew J

    2009-01-13

    Some Precambrian trace fossils have been presented as evidence for the early origin of bilaterians; the recent finding that large amoeboid protists leave macroscopic traces at the bottom of the deep ocean questions the metazoan nature of early trace fossils, stressing the importance of single-cell organisms in Precambrian biota.

  5. Traces et espaces de consommation

    Directory of Open Access Journals (Sweden)

    Franck Cochoy

    2016-10-01

    Full Text Available L’avènement des technologies numériques mobiles contribue à une évolution des modalités de distribution et de consommation. Le présent article porte sur l’usage des QR-codes, ces codes-barres bidimensionnels qui offrent à tout usager équipé d’un smartphone l’accès à des contenus commerciaux en ligne. Ils participent à l’Internet des objets et donc au couplage entre espace physique et univers numérique. Ils permettent aussi la collecte de traces numériques porteuses de sens pour les professionnels mais aussi pour les sciences sociales. Grâce à ces traces, on peut comprendre les nouveaux liens marchands tissés entre l’espace physique et le développement de flux informationnels continus. À partir de l’analyse des traces enregistrées à l’occasion de la visite des QR-codes apposés sur trois produits alimentaires (une boîte de sel, une barre chocolatée, une bouteille d’eau, notre enquête s’attache à expliciter les enjeux théoriques, méthodologiques et analytiques du processus de numérisation de l’espace de mobilité physique marchand.

  6. The Fate of Trace Contaminants in a Crewed Spacecraft Cabin Environment

    Science.gov (United States)

    Perry, Jay L.; Kayatin, Matthew J.

    2016-01-01

    Trace chemical contaminants produced via equipment offgassing, human metabolic sources, and vehicle operations are removed from the cabin atmosphere by active contamination control equipment and incidental removal by other air quality control equipment. The fate of representative trace contaminants commonly observed in spacecraft cabin atmospheres is explored. Removal mechanisms are described and predictive mass balance techniques are reviewed. Results from the predictive techniques are compared to cabin air quality analysis results. Considerations are discussed for an integrated trace contaminant control architecture suitable for long duration crewed space exploration missions.

  7. Chemical Analysis of Tire Traces in Traffic Accidents Investigation

    Directory of Open Access Journals (Sweden)

    Line Gueissaz

    2015-01-01

    Full Text Available The aim of the forensic investigation of traffic accidents is to help establish the nature and/or the circumstances of the event. This might be done with the purpose of determining the legal responsibilities of each person involved or to provide families, with a reconstruction of the events, to help understand why their relatives were injured or killed. A methodology for the comparison of chemical profiles of tire traces and tire tread samples obtained by pyrolysis-gas chromatography/mass spectrometry has been developed. Chemical profiles are represented by relative abundances of 86 compounds. The variability of the tread within and between 12 tires was assessed. Considering the level of the source as "brand and model" the intra-variability was found to be smaller than the inter-variability, leading to the complete discrimination of the 12 tires of the sample set. Braking tests were carried out on a racetrack in order to produce tire traces which origin was known. The results obtained with a supervised classification method showed that more than 94% of the replicates of the traces were correctly assigned to the class membership (i.e., brand and model of the tire at their origin. These results support that the chemical profile of one trace does not differ from the chemical profile of the tire at its origin but differs generally from the other chemical profiles of the sample set.

  8. An image analyzer system for the analysis of nuclear traces

    International Nuclear Information System (INIS)

    Cuapio O, A.

    1990-10-01

    Inside the project of nuclear traces and its application techniques to be applied in the detection of nuclear reactions of low section (non detectable by conventional methods), in the study of accidental and personal neutron dosemeters, and other but, are developed. All these studies are based on the fact that the charged particles leave latent traces of dielectric that if its are engraved with appropriate chemical solutions its are revealed until becoming visible to the optical microscope. From the analysis of the different trace forms, it is possible to obtain information of the characteristic parameters of the incident particles (charge, mass and energy). Of the density of traces it is possible to obtain information of the flow of the incident radiation and consequently of the received dose. For carry out this analysis has been designed and coupled different systems, that it has allowed the solution of diverse outlined problems. Notwithstanding it has been detected that to make but versatile this activity is necessary to have an Image Analyzer System that allow us to digitize, to process and to display the images with more rapidity. The present document, presents the proposal to carry out the acquisition of the necessary components for to assembling an Image Analyzing System, like support to the mentioned project. (Author)

  9. Trace metal speciation: Finally, correctly addressing trace metal issues

    International Nuclear Information System (INIS)

    Donard, O.F.X.

    2001-01-01

    The history of the development of trace metal speciation was discussed and the reasons behind the relatively slow widespread acceptance of its importance were presented. Partially, this was due to the lack of availability of commercial instrumentation and partly to the drive towards improving sensitivity in analytical chemistry which had focused attention on total concentration determinations. The sophistication and control of analytical instrumentation is now such that the spotlight must be turned onto the chemical species of an element present in a sample since this is what governs its behaviour in the biosphere. Indeed, several companies are currently considering the introduction of instrumentation specifically designed for metal species determination

  10. Address tracing of parallel systems via TRAPEDS

    Science.gov (United States)

    Stunkel, Craig B.; Janssens, Bob; Fuchs, W. K.

    1992-01-01

    Trace-driven simulation is an important aid in performance analysis of computer systems. Capturing address traces to use in these simulations, however, is a difficult problem for parallel processor architectures. A technique termed TRAPEDS modifies executable code (at the assembly language level) to dynamically collect the address trace from executing code. TRAPEDS has recently been implemented on both a hypercube multicomputer and a shared-memory multiprocessor. Particular attention is focused on strategies for efficiently and accurately collecting traces from both classes of parallel machines. The iPSC/2 hypercube multicomputer implementation traces both user and system code, and performs simulation on-the-fly to avoid large storage costs. Strategies are detailed for mitigating address trace distortion when collecting operating system traces. The Encore Multimax multiprocessor implementation uses a timer-based approach to reflect the interleaving of the processor traces and stores the traces to disc. Time and space overhead results are presented for both TRAPEDS implementations. Experimental cache simulation results derived from iPSC/2 address traces are presented to illustrate the importance of tracing operating system references.

  11. Simultaneous mass detection for direct inlet mass spectrometry

    International Nuclear Information System (INIS)

    Gordon, R.L.

    1979-05-01

    The evolution of analytical techniques for application in trace analysis has led to interest in practical methods for real-time monitoring. Direct inlet mass spectrometry (DIMS) has been the subject of considerable activity in recent years. A DIMS instrument is described which consists of an inlet system designed to permit particles entrained in the inlet air stream to strike a hot, oxidized rhenium filament which serves as a surface ionization source. A mass analyzer and detection system then permits identification of the elemental composition of particulates which strike the filament

  12. Nominal Mass?

    Science.gov (United States)

    Attygalle, Athula B; Pavlov, Julius

    2017-08-01

    The current IUPAC-recommended definition of the term "nominal mass," based on the most abundant naturally occurring stable isotope of an element, is flawed. We propose that Nominal mass should be defined as the sum of integer masses of protons and neutrons in any chemical species. In this way, all isotopes and isotopologues can be assigned a definitive identifier. Graphical Abstract ᅟ.

  13. Concurrent Use of H.sub.3./sub.O.sup.+./sup., NO.sup.+./sup., and O.sub.2./sub..sup.+./sup. Precursor Ions for the Detection and Quantification of Diverse Trace Gases in the Presence of Air and Breath by Selected Ion-Flow Tube mass Spectrometry

    Czech Academy of Sciences Publication Activity Database

    Smith, D.; Diskin, A. M.; Yufeng, Ji.; Španěl, Patrik

    2001-01-01

    Roč. 209, č. 1 (2001), s. 81-97 ISSN 1387-3806 R&D Projects: GA ČR GA203/97/P130 Institutional research plan: CEZ:AV0Z4040901 Keywords : SIFT-MS * trace-gas analysis * chemical ionization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.176, year: 2001

  14. New planar trace humidity sensor

    OpenAIRE

    Tiebe, Carlo; Hübert, Thomas; Lorek, Andreas; Wernecke, Roland

    2012-01-01

    A new planar sensor element for continuous coulometric trace humidity measurements in industrial gases has been developed. In order to ensure precise measurements a calibration facility including a precision dew point hygrometer as a reference device was developed. The sensor can measure the humidity in the frost point temperature range of -20 °C to -80 °C and has an expanded uncertainty of 2 K, a fast reaction time and a settling time of the entire system from 15 to 30 min.

  15. Mass spectrometers

    International Nuclear Information System (INIS)

    Manojlov, V.E.; Nedelin, P.N.; Lukichev, A.N.; Sapozhkov, L.K.; Turubarov, V.I.

    1980-01-01

    Mass spectrometers of different types are suggested to use for qualitative and quantitative analyses of gas. The operation principles of static and dynamic mass spectrometer are studied. In static mass spectrometers mass separation of ions is performed by changing the value of accelerating voltage in the ion source when retaining the magnetic field intensity. Such devices are stationary. The device mass is conditioned by the magnet mass. Mass separation in dynamic mass spectrometers is dependent on the degree of energy increment of ions in HF-electric fields. Radio frequency mass spectrometers are used with advantage for studying upper layers of an atmosphere and are installed on radiosondes and satellites. The main technical characteristics of the MX-1330 mass spectrometer, the basis of which is the analyzer with 180 deg deviation of an ion beam in the field of permanent magnet, are presented. The device is intended for controlling the environment and permits to analyze gases with a molecular mass up to 450 using various systems of gas filling. The error of determination of molecular substance is not greater than +-3 %; the magnetic field intensity constitutes 4.8x10 5 A/m; the supply voltage is 380/220 V; the total power is 5.0 kVA [ru

  16. Isotope tracing enhancement of chemiluminescence assays for nitric oxide research.

    Science.gov (United States)

    Cornelius, Julia; Tran, Tuan; Turner, Nicole; Piazza, Abigail; Mills, Lauren; Slack, Ryan; Hauser, Sean; Alexander, J Steven; Grisham, Matthew B; Feelisch, Martin; Rodriguez, Juan

    2009-02-01

    Chemiluminescence assays are used widely for the detection of nitric oxide (NO)-derived species in biological fluids and tissues. Here, we demonstrate that these assays can be interfaced with mass-sensitive detectors for parallel determination of isotopic abundance. Results obtained with tri-iodide and ascorbic acid-based reductive assays indicate that mass spectrometric detection enables NO isotope-tracing experiments to be carried out to a limit of detectability of a few picomoles, a sensitivity similar to that of standard gas phase chemiluminescence methods. The advantage afforded by mass spectrometric detection is demonstrated using the murine macrophage cell line J774, which is shown here to reduce 15NO3- to 15NO2- under anoxic conditions. The particular combination of an analytical and cellular system described here may hold promise for future characterization of the enzymatic pathways contributing to mammalian nitrate reductase activity, without background interference from 14NO2- derived from other sources.

  17. Brain trace elements and aging

    International Nuclear Information System (INIS)

    Hebbrecht, Geert; Maenhaut, Willy; Reuck, Jacques de

    1999-01-01

    Degenerative mechanisms involved in the aging process of the brain are to a certain extent counteracted by repair mechanisms. In both degenerative and recovery processes, trace elements are involved. The present study focused on the role of two minor (i.e., K and Ca) and six trace elements (i.e., Mn, Fe, Cu, Zn, Se and Rb) in the aging process. The elements were determined by PIXE in cerebral cortex and white matter, basal ganglia, brainstem and cerebellar cortex of 18 postmortem human brains, from persons without a history of neurologic or psychiatric disease who deceased between the age of 7 and 79. This age range allowed us to study the relationship between elemental concentrations and age. The most prominent findings were a concentration decrease for K and Rb and a concentration increase for the elements Ca, Fe, Zn and Se. The study supports recent findings that Ca and Fe are involved in brain degenerative processes initiated by oxygen free radicals, whereas Zn and Se are involved in immunological reactions counteracting the aging process

  18. On the hadron mass decomposition

    Science.gov (United States)

    Lorcé, Cédric

    2018-02-01

    We argue that the standard decompositions of the hadron mass overlook pressure effects, and hence should be interpreted with great care. Based on the semiclassical picture, we propose a new decomposition that properly accounts for these pressure effects. Because of Lorentz covariance, we stress that the hadron mass decomposition automatically comes along with a stability constraint, which we discuss for the first time. We show also that if a hadron is seen as made of quarks and gluons, one cannot decompose its mass into more than two contributions without running into trouble with the consistency of the physical interpretation. In particular, the so-called quark mass and trace anomaly contributions appear to be purely conventional. Based on the current phenomenological values, we find that in average quarks exert a repulsive force inside nucleons, balanced exactly by the gluon attractive force.

  19. Tracing Young and Old Groundwater Using Atom Trap Trace Analysis

    Science.gov (United States)

    Mueller, P.; Zappala, J. C.; O'Connor, T. P.; Bailey, K. G.; Bishof, M.; Lu, Z. T.

    2016-12-01

    Due to its simple production and transport in the terrestrial environment, 81Kr (half-life = 230,000 yr) is an ideal tracer for old water and ice with mean residence times in the range of 105-106 years. Likewise, the anthropogenic isotope 85Kr (half-life = 10.8 yrs), which is predominantly introduced into the atmopshere through nuclear fuel reprocessing activities, is a valuable tracer of respectively young groundwater. In recent years, the ultra-trace analysis of both isotopes has been made available to the earth science community at large thanks to the development of Atom Trap Trace Analysis (ATTA), an efficient and selective laser-based atom counting method. Further upgrades and improvements to the ATTA instrument at Argonne National Laboratory have recently allowed us to measure Kr isotope ratios with relative uncertainties at the level of 1% while also significantly increasing sample throughput and reducing sample size requirements. As examples of recent achievements, we have placed a 1.4% limit on the anthropogenic contribution to 81Kr relative to its natural abundance by precisely comparing the 81Kr abundance in a 1940 athmospheric sample to that of modern air, we are now able to handle samples as small as 1µL of Kr gas (STP), and we can measure 85Kr isotope abundances in as little as four hours of measurement time enabling us to analyze six or more samples in 24 hrs. This work is supported by Department of Energy, Office of Nuclear Physics, under Contract No. DEAC02-06CH11357.

  20. Diagnosing MOV problems using comparative trace analysis

    International Nuclear Information System (INIS)

    Leon, R.L.

    1992-01-01

    The paper presents the concept of comparative trace analysis and shows it to be very effective in diagnosing motor operated valve (MOV) problems. Comparative trace analysis is simply the process of interpreting simultaneously gathered traces, each presenting a different perspective on the same series of events. The opening and closing of a motor operated valve is such a series of events. The simultaneous traces are obtained using Liberty Technologies' Valve Operation Test and Evaluation System (VOTES)reg-sign. The traces include stem thrust, motor current, motor power factor, motor power, switch actuations, vibration in three different frequency bands, spring pack displacement, and spring pack force. Spare and auxiliary channels enable additional key parameters to be measured, such as differential pressure and stem displacement. Though not specifically illustrated in this paper, the VOTES system also provides for FFT analysis on all traces except switches

  1. Neutrino mass

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1992-01-01

    Despite intensive experimental work since the neutrino's existence was proposed by Pauli 60 years ago, and its first observation by Reines and Cowan almost 40 years ago, the neutrino's fundamental properties remain elusive. Among those properties are the masses of the three known flavors, properties under charge conjugation, parity and time-reversal, and static and dynamic electromagnetic moments. Mass is perhaps the most fundamental, as it constrains the other properties. The present status of the search for neutrino mass is briefly reviewed

  2. Trace maps of general substitutional sequences

    International Nuclear Information System (INIS)

    Kolar, M.; Nori, F.

    1990-01-01

    It is shown that for arbitrary n, there exists a trace map for any n-letter substitutional sequence. Trace maps are explicitly obtained for the well-known circle and Rudin-Shapiro sequences which can be defined by means of substitution rules on three and four letters, respectively. The properties of the two trace maps and their consequences for various spectral properties are briefly discussed

  3. MASS SPECTROMETER

    Science.gov (United States)

    White, F.A.

    1960-08-23

    A mass spectrometer is designed with a first adjustable magnetic field for resolving an ion beam into beams of selected masses, a second adjustable magnetic field for further resolving the ion beam from the first field into beams of selected masses, a thin foil disposed in the path of the beam between the first and second magnets to dissociate molecular ions incident thereon, an electrostatic field for further resolving the ion beam from the second field into beams of selected masses, and a detector disposed adjacent to the electrostatic field to receive the ion beam.

  4. In vivo tracing of organophosphorus pesticides in cabbage (Brassica parachinensis) and aloe (Barbadensis)

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Junlang; Chen, Guosheng; Zhou, Hong; Xu, Jianqiao; Wang, Fuxin; Zhu, Fang, E-mail: ceszf@mail.sysu.edu.cn; Ouyang, Gangfeng, E-mail: cesoygf@mail.sysu.edu.cn

    2016-04-15

    In vivo solid-phase microextraction (SPME) sampling method coupled with gas chromatography–mass spectrometry (GC–MS) analysis was employed to trace the uptake and elimination of organophosphorus pesticides (OPPs) in two kinds of edible plants, cabbage (Brassica parachinensis) and aloe (Barbadensis). The metabolism of fenthion in aloe was also investigated by the liquid chromatography tandem mass spectrometry analysis (LC–MS/MS) to understand the fate of OPPs in living plants better. Transpiration stream concentration factor (TSCF) and depuration rate constants of the OPPs in living plants were obtained therein. The health risk of the OPPs treated aloe was estimated by the maximum residue limit (MRL) approach, and it revealed that the OPPs were rather safe for their fast degradable property. However, peak concentration of fenthion-sulfoxide was found to exceed the MRL and was higher than that of the parent fenthion, which indicated the potential risk of pesticide metabolites. This study highlighted the application of in vivo SPME for contaminant tracing in different living edible plants. The in vivo tracing method is very convenient and can provide more data to evaluate the risk of different pesticides, which are very important for the safety of agriculture production. - Highlights: • In vivo SPME was employed to sample organophosphorus pesticides in vegetables. • Uptake and elimination of OPPs were traced in cabbage and aloe. • In vivo tracing of fenthion demonstrated its metabolites could be rather dangerous. • The risks of OPPs were assessed based on the in vivo tracing data.

  5. In vivo tracing of organophosphorus pesticides in cabbage (Brassica parachinensis) and aloe (Barbadensis)

    International Nuclear Information System (INIS)

    Qiu, Junlang; Chen, Guosheng; Zhou, Hong; Xu, Jianqiao; Wang, Fuxin; Zhu, Fang; Ouyang, Gangfeng

    2016-01-01

    In vivo solid-phase microextraction (SPME) sampling method coupled with gas chromatography–mass spectrometry (GC–MS) analysis was employed to trace the uptake and elimination of organophosphorus pesticides (OPPs) in two kinds of edible plants, cabbage (Brassica parachinensis) and aloe (Barbadensis). The metabolism of fenthion in aloe was also investigated by the liquid chromatography tandem mass spectrometry analysis (LC–MS/MS) to understand the fate of OPPs in living plants better. Transpiration stream concentration factor (TSCF) and depuration rate constants of the OPPs in living plants were obtained therein. The health risk of the OPPs treated aloe was estimated by the maximum residue limit (MRL) approach, and it revealed that the OPPs were rather safe for their fast degradable property. However, peak concentration of fenthion-sulfoxide was found to exceed the MRL and was higher than that of the parent fenthion, which indicated the potential risk of pesticide metabolites. This study highlighted the application of in vivo SPME for contaminant tracing in different living edible plants. The in vivo tracing method is very convenient and can provide more data to evaluate the risk of different pesticides, which are very important for the safety of agriculture production. - Highlights: • In vivo SPME was employed to sample organophosphorus pesticides in vegetables. • Uptake and elimination of OPPs were traced in cabbage and aloe. • In vivo tracing of fenthion demonstrated its metabolites could be rather dangerous. • The risks of OPPs were assessed based on the in vivo tracing data.

  6. ATTREX-Aircraft_insitu_TraceGas_Measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — This collection consists of the observational data from the Airborne Tropical TRopopause EXperiment (ATTREX) trace gas measurements from three field deployments in...

  7. RAY TRACING IMPLEMENTATION IN JAVA PROGRAMMING LANGUAGE

    Directory of Open Access Journals (Sweden)

    Aybars UĞUR

    2002-01-01

    Full Text Available In this paper realism in computer graphics and components providing realism are discussed at first. It is mentioned about illumination models, surface rendering methods and light sources for this aim. After that, ray tracing which is a technique for creating two dimensional image of a three-dimensional virtual environment is explained briefly. A simple ray tracing algorithm was given. "SahneIzle" which is a ray tracing program implemented in Java programming language which can be used on the internet is introduced. As a result, importance of network-centric ray tracing software is discussed.

  8. Mass Spectrometry in the Home and Garden

    Science.gov (United States)

    Pulliam, Christopher J.; Bain, Ryan M.; Wiley, Joshua S.; Ouyang, Zheng; Cooks, R. Graham

    2015-02-01

    Identification of active components in a variety of chemical products used directly by consumers is described at both trace and bulk levels using mass spectrometry. The combination of external ambient ionization with a portable mass spectrometer capable of tandem mass spectrometry provides high chemical specificity and sensitivity as well as allowing on-site monitoring. These experiments were done using a custom-built portable ion trap mass spectrometer in combination with the ambient ionization methods of paper spray, leaf spray, and low temperature plasma ionization. Bactericides, garden chemicals, air fresheners, and other products were examined. Herbicide applied to suburban lawns was detected in situ on single leaves 5 d after application.

  9. Trace desulfurization. [DOE patent application

    Science.gov (United States)

    Chen, H.L.; Stevens, C.G.

    A method for reducing a trace concentration of sulfur-containing compounds in a gas stream from about one part in 10/sup 4/ to about one part in 10/sup 7/. The method includes the steps of irradiating the gas stream with an energy source which has a central emission frequency chosen to substantially match a wavelength of energy absorption of the sulfur-containing compounds and of subsequently contacting the gas stream with a reactive surface which includes a reactant selected from elemental metals and metal oxides so that metallic sulfur-containing compounds are formed. The reduction in concentration allows the gas stream to be processed in certain reactions having catalysts which would otherwise be poisoned by the sulfur-containing compounds.

  10. Zinc: a multipurpose trace element

    Energy Technology Data Exchange (ETDEWEB)

    Stefanidou, M.; Maravelias, C.; Dona, A.; Spiliopoulou, C. [University of Athens, Department of Forensic Medicine and Toxicology, Athens (Greece)

    2006-01-01

    Zinc (Zn) is one of the most important trace elements in the body and it is essential as a catalytic, structural and regulatory ion. It is involved in homeostasis, in immune responses, in oxidative stress, in apoptosis and in ageing. Zinc-binding proteins (metallothioneins, MTs), are protective in situations of stress and in situations of exposure to toxic metals, infections and low Zn nutrition. Metallothioneins play a key role in Zn-related cell homeostasis due to their high affinity for Zn, which is in turn relevant against oxidative stress and immune responses, including natural killer (NK) cell activity and ageing, since NK activity and Zn ion bioavailability decrease in ageing. Physiological supplementation of Zn in ageing and in age-related degenerative diseases corrects immune defects, reduces infection relapse and prevents ageing. Zinc is not stored in the body and excess intakes result in reduced absorption and increased excretion. Nevertheless, there are cases of acute and chronic Zn poisoning. (orig.)

  11. Serum Concentrations of Trace Elements in Patients with Tuberculosis and Its Association with Treatment Outcome

    Directory of Open Access Journals (Sweden)

    Rihwa Choi

    2015-07-01

    Full Text Available Deficiencies in essential trace elements are associated with impaired immunity in tuberculosis infection. However, the trace element concentrations in the serum of Korean patients with tuberculosis have not yet been investigated. This study aimed to compare the serum trace element concentrations of Korean adult patients with tuberculosis with noninfected controls and to assess the impact of serum trace element concentration on clinical outcome after antituberculosis treatment. The serum concentrations of four trace elements in 141 consecutively recruited patients with tuberculosis and 79 controls were analyzed by inductively coupled plasma-mass spectrometry. Demographic characteristics were also analyzed. Serum cobalt and copper concentrations were significantly higher in patients with tuberculosis compared with controls, while zinc and selenium concentrations were significantly lower (p < 0.01. Moreover, serum selenium and zinc concentrations were positively correlated (ρ = 0.41, p < 0.05. A high serum copper concentration was associated with a worse clinical outcome, as assessed after one month of antituberculosis therapy. Specifically, culture-positive patients had higher serum copper concentrations than culture-negative patients (p < 0.05. Patients with tuberculosis had altered serum trace element concentrations. Further research is needed to elucidate the roles of individual trace elements and to determine their clinical impact on patients with tuberculosis.

  12. Total reflection X-ray spectrometry (TXRF) for trace elements assessment in edible clams.

    Science.gov (United States)

    Marguí, Eva; de Fátima Marques, Alexandra; de Lurdes Prisal, Maria; Hidalgo, Manuela; Queralt, Ignasi; Carvalho, Maria Luisa

    2014-01-01

    The present contribution presents a preliminary investigation of the chemical composition with respect to major, minor, trace, and ultratrace elements in several clam species that are frequently used for human consumption in Portuguese markets and worldwide. In order to use a simple and rapid analytical methodology for clam analysis, energy dispersive X-ray fluorescence (EDXRF) spectrometry and total reflection X-ray fluorescence (TXRF) spectrometry were selected as analytical techniques. The analytical capabilities of TXRF spectrometry were evaluated for the determination of minor and trace elements in commercial edible clams. We compared the direct analysis of powdered suspensions (using different sample amounts and dispersant agents) with the analysis of the digested samples for trace element determination. Inductively coupled plasma mass spectrometry analysis of clam digests was also performed to evaluate the analytical possibilities of TXRF spectrometry for trace and ultratrace analysis.

  13. The role of trace elements in male infertility.

    Science.gov (United States)

    Abou-Shakra, F R; Ward, N I; Everard, D M

    1989-08-01

    The elemental status of seminal plasma collected from four populations subdivided on the basis of sperm counts is presented. Elemental analysis was performed by inductively coupled plasma-source mass spectrometry (ICP-MS) for calcium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, nickel, lead, rubidium, selenium, vanadium, and zinc. The majority of elements reflected no statistically significant differences among the four groups. The role of trace elements in infertility may be more directly related to sperm and whole semen than seminal plasma levels.

  14. Adsorption and filtration of trace contaminants in aqueous effluents

    Energy Technology Data Exchange (ETDEWEB)

    Irizarry, M.M.; Anthony, D.B.

    1971-04-28

    The removal of trace copper contaminants from aqueous effluents by means of adsorption on ion exchange resins was studied. A semicontinuous, axial filtration device was used to obtain mass transfer data as a function of the operating parameters: flow rate, resin volume and size, temperature, rotational speed, and system geometry. Correlation of data based on power dissipation per unit volume is presented. Operation of the unit involved high product fluxes (1000 to 15,000 gpd/ft/sup 2/) and adsorption efficiencies (90 to 99+%) coupled with low pressure drops (0 to 10 psi).

  15. Mass Society

    DEFF Research Database (Denmark)

    Borch, Christian

    2017-01-01

    Mass society is a societal diagnosis that emphasizes – usually in a pejorative, modernity critical manner – a series of traits allegedly associated with modern society, such as the leveling of individuality, moral decay, alienation, and isolation. As such, the notion of mass society generalizes...

  16. Context-sensitive trace inlining for Java.

    Science.gov (United States)

    Häubl, Christian; Wimmer, Christian; Mössenböck, Hanspeter

    2013-12-01

    Method inlining is one of the most important optimizations in method-based just-in-time (JIT) compilers. It widens the compilation scope and therefore allows optimizing multiple methods as a whole, which increases the performance. However, if method inlining is used too frequently, the compilation time increases and too much machine code is generated. This has negative effects on the performance. Trace-based JIT compilers only compile frequently executed paths, so-called traces, instead of whole methods. This may result in faster compilation, less generated machine code, and better optimized machine code. In the previous work, we implemented a trace recording infrastructure and a trace-based compiler for [Formula: see text], by modifying the Java HotSpot VM. Based on this work, we evaluate the effect of trace inlining on the performance and the amount of generated machine code. Trace inlining has several major advantages when compared to method inlining. First, trace inlining is more selective than method inlining, because only frequently executed paths are inlined. Second, the recorded traces may capture information about virtual calls, which simplify inlining. A third advantage is that trace information is context sensitive so that different method parts can be inlined depending on the specific call site. These advantages allow more aggressive inlining while the amount of generated machine code is still reasonable. We evaluate several inlining heuristics on the benchmark suites DaCapo 9.12 Bach, SPECjbb2005, and SPECjvm2008 and show that our trace-based compiler achieves an up to 51% higher peak performance than the method-based Java HotSpot client compiler. Furthermore, we show that the large compilation scope of our trace-based compiler has a positive effect on other compiler optimizations such as constant folding or null check elimination.

  17. Monsoon signatures in trace gas records from Cape Rama, India

    International Nuclear Information System (INIS)

    Bhattacharya, S.K.; Jani, R.A.; Borole, D.V.; Francey, R.J.; Allison, C.E.; Masarie, K.A.

    2002-01-01

    Concentrations of trace gases CO 2 , CH 4 , CO, N 2 O and H 2 , and the stable carbon and oxygen isotopic composition of CO 2 have been measured in air samples collected from Cape Rama, a coastal station on the west coast of India, since 1993. The data show clear signatures of continental and oceanic air mass resulting in complex seasonal variation of trace gas characteristics. The regional atmospheric circulation in the Indian Ocean and Arabian Sea undergoes biannual reversal in low-level winds associated with the yearly migration of the inter-tropical convergence zone (ITCZ). From June to September, the wind is from the equatorial Indian Ocean to the Indian subcontinent (southwest monsoon) and brings in pristine marine air. From December to February, dry continental winds blow from the northeast and transport continental emissions to the ocean (northeast monsoon). Detailed transport and chemical modelling will be necessary to interpret these records, however the potential to identify and constrain the regional trace gas emissions appears to be high. (author)

  18. Digital Stratigraphy: Contextual Analysis of File System Traces in Forensic Science.

    Science.gov (United States)

    Casey, Eoghan

    2017-12-28

    This work introduces novel methods for conducting forensic analysis of file allocation traces, collectively called digital stratigraphy. These in-depth forensic analysis methods can provide insight into the origin, composition, distribution, and time frame of strata within storage media. Using case examples and empirical studies, this paper illuminates the successes, challenges, and limitations of digital stratigraphy. This study also shows how understanding file allocation methods can provide insight into concealment activities and how real-world computer usage can complicate digital stratigraphy. Furthermore, this work explains how forensic analysts have misinterpreted traces of normal file system behavior as indications of concealment activities. This work raises awareness of the value of taking the overall context into account when analyzing file system traces. This work calls for further research in this area and for forensic tools to provide necessary information for such contextual analysis, such as highlighting mass deletion, mass copying, and potential backdating. © 2017 American Academy of Forensic Sciences.

  19. Reverse ray tracing for transformation optics.

    Science.gov (United States)

    Hu, Chia-Yu; Lin, Chun-Hung

    2015-06-29

    Ray tracing is an important technique for predicting optical system performance. In the field of transformation optics, the Hamiltonian equations of motion for ray tracing are well known. The numerical solutions to the Hamiltonian equations of motion are affected by the complexities of the inhomogeneous and anisotropic indices of the optical device. Based on our knowledge, no previous work has been conducted on ray tracing for transformation optics with extreme inhomogeneity and anisotropicity. In this study, we present the use of 3D reverse ray tracing in transformation optics. The reverse ray tracing is derived from Fermat's principle based on a sweeping method instead of finding the full solution to ordinary differential equations. The sweeping method is employed to obtain the eikonal function. The wave vectors are then obtained from the gradient of that eikonal function map in the transformed space to acquire the illuminance. Because only the rays in the points of interest have to be traced, the reverse ray tracing provides an efficient approach to investigate the illuminance of a system. This approach is useful in any form of transformation optics where the material property tensor is a symmetric positive definite matrix. The performance and analysis of three transformation optics with inhomogeneous and anisotropic indices are explored. The ray trajectories and illuminances in these demonstration cases are successfully solved by the proposed reverse ray tracing method.

  20. Properties of the Bayesian Knowledge Tracing Model

    Science.gov (United States)

    van de Sande, Brett

    2013-01-01

    Bayesian Knowledge Tracing is used very widely to model student learning. It comes in two different forms: The first form is the Bayesian Knowledge Tracing "hidden Markov model" which predicts the probability of correct application of a skill as a function of the number of previous opportunities to apply that skill and the model…

  1. Entities of interest : Discovery in digital traces

    NARCIS (Netherlands)

    Graus, D.P.

    2017-01-01

    In the era of big data, we continuously — and at times unknowingly — leave behind digital traces, by browsing, sharing, posting, liking, searching, watching, and listening to online content. Aggregated, these digital traces can provide powerful insights into the behavior, preferences, activities,

  2. Trace element metabolism in man and animals

    International Nuclear Information System (INIS)

    Kirchgessner, M.

    1977-01-01

    Uptake, distribution, storage, excretion of different trace elements and resulting disturbances are investigated in blood and organs in animal experiments and in human diagnostics with the aid of radioisotopes. Apart from this, untritional disturbances are mentioned. Finally, future aspects of physiological trace element examinations are listed. (AJ) 891 AJ [de

  3. Trace elements characterization of the hydrothermally deposited ...

    African Journals Online (AJOL)

    With the exception of higher barium contents in pelites, trace element contents in the psammitic and pelitic gneisses show some similarities while in the hydrothermally altered rocks where gemstones (tanzanite and green grossular) are localized reveal that the following trace elements: Ba, Cu, Mo, Ni, Rb, Sr, U, V and Zn ...

  4. Trace maps for arbitrary substitution sequences

    International Nuclear Information System (INIS)

    Avishai, Y.

    1993-01-01

    The discovery of quasi-crystals and their 1-dimensional modeling have led to a deep mathematical study of Schroedinger operators with an arbitrary deterministic potential sequence. In this work we address this problem and find trace maps for an arbitrary substitution sequence. our trace maps have lower dimensionality than those of Kolar and Nori, which make them quite attractive for actual applications. (authors)

  5. Protostellar accretion traced with chemistry

    DEFF Research Database (Denmark)

    Frimann, Søren; Jørgensen, Jes Kristian; Dunham, Michael M.

    2017-01-01

    . Our aim is to characterise protostellar accretion histories towards individual sources by utilising sublimation and freeze-out chemistry of CO. Methods. A sample of 24 embedded protostars are observed with the Submillimeter Array (SMA) in context of the large program "Mass Assembly of Stellar Systems...

  6. Mass hysteria

    CERN Document Server

    Hellemans, Alexander

    2004-01-01

    Considerable research is being undertaken to identify the Higgs particle that is believed to give things their mass. According to the standard model, what we call mass is really an indication of how strongly particles interact with an invisible syrupy substance called the Higgs field. Quantum mechanics say that the mass-giving field can also be thought of as a sea of electrically neutral Higgs particles that should be dislodged in collisions between subatomic particles with high enough energies. Particle physicists expect the Higgs to exist only for a fleeting moment before decaying into other particles, which are caught in a detector. (Edited abstract).

  7. Double-trace deformations of conformal correlations

    Science.gov (United States)

    Giombi, Simone; Kirilin, Vladimir; Perlmutter, Eric

    2018-02-01

    Large N conformal field theories often admit unitary renormalization group flows triggered by double-trace deformations. We compute the change in scalar four-point functions under double-trace flow, to leading order in 1/ N. This has a simple dual in AdS, where the flow is implemented by a change of boundary conditions, and provides a physical interpretation of single-valued conformal partial waves. We extract the change in the conformal dimensions and three-point coefficients of infinite families of double-trace composite operators. Some of these quantities are found to be sign-definite under double-trace flow. As an application, we derive anomalous dimensions of spinning double-trace operators comprised of non-singlet constituents in the O( N) vector model.

  8. Olivine Major and Trace Element Compositions in Southern Payenia Basalts, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Portnyagin, Maxim; Hoernle, Kaj

    2015-01-01

    Olivine major and trace element compositions from 12 basalts from the southern Payenia volcanic province in Argentina have been analyzed by electron microprobe and laser ablation inductively coupled plasma mass spectrometry. The olivines have high Fe/Mn and low Ca/Fe and many fall at the end of t...

  9. MESOLITHIC HUMAN BONES FROM THE UPPER VOLGA BASIN : RADIOCARBON AND TRACE ELEMENTS

    NARCIS (Netherlands)

    Alexandrovskiy, A. L.; Alexandrovskaya, E. I.; Zhilin, M. I.; van der Plicht, J.

    2009-01-01

    Human bones from 3 Mesolithic sites in the Upper Volga basin were analyzed for trace elements, and dated by accelerator mass spectrometry (AMS). The radiocarbon dates of the bones correspond to the Mesolithic era. However, some dates differ from those obtained for the enclosing deposits and for the

  10. Abdominal mass

    Science.gov (United States)

    ... such as CBC and blood chemistry Colonoscopy EGD Isotope study Sigmoidoscopy Alternative Names Mass in the abdomen ... WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A. ...

  11. Scrotal masses

    Science.gov (United States)

    ... in your scrotum. Any new growth in the testicle or scrotum needs to be checked by your provider to determine if it may be testicular cancer. Prevention You can prevent scrotal masses caused by sexually ...

  12. Australis: AMS for ultra sensitive trace element and isotopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Sie, S.H.; Suter, G.F. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1993-12-31

    The accelerator mass spectrometer (AMS) at the CSIRO HIAF laboratory is being upgraded to enable in-situ measurements of ultratraces and isotopic-ratios in mineralogical applications. The upgraded system will include a microbeam Cs ion source which is designed to produce better than 50 micrometre diameter Cs beam to enable analyses of monomineralic grains. The Cs primary beam will be mass analysed in order to minimize contamination of the sample. The detection system will be upgraded to enable analyses of elements up to U, at 2 MV terminal voltage for charge states 4 and 5. The system will be known as AUSTRALIS: A.M.S. for Ultra Sensitive TRAce eLement and Isotopic Studies. An overview of the system and the anticipated applications in minerals exploration and mining research are presented. 4 refs., 1 fig.

  13. Traces of hysteria in novels.

    Science.gov (United States)

    Haan, Joost; Koehler, Peter J

    2014-01-01

    There have been many descriptions of presumed 'hysterics' in fiction, many appearing in French literature, but also in a number of other languages. It is clear that contemporary medical ideas and insights about hysteria had a major influence on its depiction in novels. This is particularly true for naturalistic literature, which has been the subject of previous reviews. Here, we focus on a more recent novel: Human Traces by Sebastian Faulks (2005). What is special about the depiction of hysteria in this work is that the presumed 'hysteric' turns out not to be hysteric at all. In the novel, as well as in this chapter, the diagnosis of hysteria is discussed in the light of theories about hysteria of around 1900. For comparison, we present some examples of true 'hysterics' as they occur in fiction. Since it has become clear that severe nonpsychiatric diseases such as an ovarian teratoma can lead to bizarre phenotypes, the association of 'hysteria' with the womb has to be seen in another light.

  14. Tracing Anthropogenic Pollution Through Dendrochemistry

    Science.gov (United States)

    Rocha, E.; Gunnarson, B. E.; Holzkaemper, S.

    2017-12-01

    The growing concern regarding pollution effects on the environment and human health demands new control strategies and monitoring tools. In this study we assess the potential of using dendrochemistry as a forensic tool to investigate chemical contamination patterns in the surroundings of a former glass factory in Southern Sweden. Tree-ring width chronologies were produced from exposed and non-exposed sites. Using energy disperse X-ray fluorescence (EDXRF) technique, tree cores of Scots Pine (Pinus sylvestris), Norway spruce (Picea Abies) and Populus tremula (European Aspen) were analysed for their elemental composition in accordance with previous soil analysis done in the area. Traces of barium and considerable alteration of the chlorine profiles were successfully detected confirming the potential of the method to record environmental releases. The dendrochemical analysis also highlighted the differences in the response of tree species to elements uptake (root sensitivity) and the importance of metals bioavailability. Finally, the adopted sampling strategy is of outmost importance to the success of the method.

  15. Identifying and Tracing User Needs

    Science.gov (United States)

    To, C.; Tauer, E.

    2017-12-01

    Providing adequate tools to the user community hinges on reaching the specific goals and needs behind the intended application of the tool. While the approach of leveraging user-supplied inputs and use cases to identify those goals is not new, there frequently remains the challenge of tracing those use cases through to implementation in an efficient and manageable fashion. Processes can become overcomplicated very quickly, and additionally, explicitly mapping progress towards the achievement of the user demands can become overwhelming when hundreds of use-cases are at play. This presentation will discuss a demonstrated use-case approach that has achieved an initial success with a tool re-design and deployment, the means to apply use cases in the generation of a roadmap for future releases over time, and the ability to include and adjust to new user requirements and suggestions with minimal disruption to the traceability. It is hoped that the findings and lessons learned will help make use case employment easier for others seeking to create user-targeted capabilities.

  16. Particle Tracing Modeling with SHIELDS

    Science.gov (United States)

    Woodroffe, J. R.; Brito, T. V.; Jordanova, V. K.

    2017-12-01

    The near-Earth inner magnetosphere, where most of the nation's civilian and military space assets operate, is an extremely hazardous region of the space environment which poses major risks to our space infrastructure. Failure of satellite subsystems or even total failure of a spacecraft can arise for a variety of reasons, some of which are related to the space environment: space weather events like single-event-upsets and deep dielectric charging caused by high energy particles, or surface charging caused by low to medium energy particles; other space hazards are collisions with natural or man-made space debris, or intentional hostile acts. A recently funded project through the Los Alamos National Laboratory (LANL) Directed Research and Development (LDRD) program aims at developing a new capability to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. The project goals are to understand the dynamics of the surface charging environment (SCE), the hot (keV) electrons on both macro- and microscale. These challenging problems are addressed using a team of world-class experts and state-of-the-art physics-based models and computational facilities. We present first results of a coupled BATS-R-US/RAM-SCB/Particle Tracing Model to evaluate particle fluxes in the inner magnetosphere. We demonstrate that this setup is capable of capturing the earthward particle acceleration process resulting from dipolarization events in the tail region of the magnetosphere.

  17. Mass spectrometry with accelerators.

    Science.gov (United States)

    Litherland, A E; Zhao, X-L; Kieser, W E

    2011-01-01

    As one in a series of articles on Canadian contributions to mass spectrometry, this review begins with an outline of the history of accelerator mass spectrometry (AMS), noting roles played by researchers at three Canadian AMS laboratories. After a description of the unique features of AMS, three examples, (14)C, (10)Be, and (129)I are given to illustrate the methods. The capabilities of mass spectrometry have been extended by the addition of atomic isobar selection, molecular isobar attenuation, further ion acceleration, followed by ion detection and ion identification at essentially zero dark current or ion flux. This has been accomplished by exploiting the techniques and accelerators of atomic and nuclear physics. In 1939, the first principles of AMS were established using a cyclotron. In 1977 the selection of isobars in the ion source was established when it was shown that the (14)N(-) ion was very unstable, or extremely difficult to create, making a tandem electrostatic accelerator highly suitable for assisting the mass spectrometric measurement of the rare long-lived radioactive isotope (14)C in the environment. This observation, together with the large attenuation of the molecular isobars (13)CH(-) and (12)CH 2(-) during tandem acceleration and the observed very low background contamination from the ion source, was found to facilitate the mass spectrometry of (14)C to at least a level of (14)C/C ~ 6 × 10(-16), the equivalent of a radiocarbon age of 60,000 years. Tandem Accelerator Mass Spectrometry, or AMS, has now made possible the accurate radiocarbon dating of milligram-sized carbon samples by ion counting as well as dating and tracing with many other long-lived radioactive isotopes such as (10)Be, (26)Al, (36)Cl, and (129)I. The difficulty of obtaining large anion currents with low electron affinities and the difficulties of isobar separation, especially for the heavier mass ions, has prompted the use of molecular anions and the search for alternative

  18. The trace anomaly and massless scalar degrees of freedom

    Energy Technology Data Exchange (ETDEWEB)

    Gianotti, Maurizio [Los Alamos National Laboratory; Mottola, Emil [Los Alamos National Laboratory

    2008-01-01

    The trace anomaly of quantum fields in electromagnetic or gravitational backgrounds implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. Considering first the axial anomaly and using QED as an example, we compute the full one-loop triangle amplitude of the fermionic stress tensor with two current vertices, {open_square}T{sup {mu}{nu}}J{sup {alpha}}J{sup {beta}}, and exhibit the scalar pole in this amplitude associated with the trace anomaly, in the limit of zero electron mass m{yields}0. To emphasize the infrared aspect of the anomaly, we use a dispersive approach and show that this amplitude and the existence of the massless scalar pole is determined completely by its ultraviolet finite terms, together with the requirements of Poincare invariance of the vacuum, Bose symmetry under interchange of J{sup {alpha}} and J{sup {beta}}, and vector current and stress-tensor conservation. We derive a sum rule for the appropriate positive spectral function corresponding to the discontinuity of the triangle amplitude, showing that it becomes proportional to {delta}(k{sup 2}) and therefore contains a massless scalar intermediate state in the conformal limit of zero electron mass. The effective action corresponding to the trace of the triangle amplitude can be expressed in local form by the introduction of two scalar auxiliary fields which satisfy massless wave equations. These massless scalar degrees of freedom couple to classical sources, contribute to gravitational scattering processes, and can have long range gravitational effects.

  19. Methods for analysis of trace elements in coal, coal fly ash, soil, and plant samples. [59 refs

    Energy Technology Data Exchange (ETDEWEB)

    Slates, R.V.

    1976-11-01

    Results of a literature search are presented, and analytical methods are proposed for studies of trace elements in coal, coal ash residue, soil, and vegetation. Increased trace element levels in soils and plants collected near power plants have been reported by several investigators. Many sample dissolution and analysis techniques were used in the reported studies. A nine-laboratory comparison of trace element analyses for a variety of methods showed excessive variation relative to quoted uncertainty limits. Analysis results from a subsequent four-laboratory comparison of instrumental nuclear techniques for trace element analysis agreed with the National Bureau of Standards certified values for all nine elements determined. Instrumental neutron activation analysis, spark source mass spectrometry, and atomic absorption spectrometry are proposed as primary analysis methods for coal, coal ash, soil, and plants in a Savannah River Laboratory study of trace elements. Bomb procedures are proposed for dissolution of samples.

  20. Discrimination of forensic trace evidence using laser induced breakdown spectroscopy

    Science.gov (United States)

    Bridge, Candice Mae

    Elemental analysis in forensic laboratories can be tedious and many trace evidence items are not analyzed to determine their elemental composition. Presently, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) is the primary analytical tool for determining the elemental composition of trace evidence items. However, due to the time it takes to obtain the required vacuum and the limited number of samples that can be analyzed at any one time, SEM-EDS can be impractical for a high volume of evidence items. An alternative instrument that can be used for this type of analysis is laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). While LA-ICP-MS is a very precise and quantitative analytical method that determines elemental composition based on isotopic mass measurements; however, the instrumentation is relatively expensive and therefore is budgetarily prohibitive for many forensic laboratories. It is the purpose of this research to evaluate an inexpensive instrument that can potentially provide rapid elemental analysis for many forensic laboratories. Laser induced breakdown spectroscopy (LIBS) is an analytical method that meets these requirements and offers information about the elemental composition based on ionic, atomic and diatomic molecular emissions.

  1. Spoken word recognition without a TRACE

    Science.gov (United States)

    Hannagan, Thomas; Magnuson, James S.; Grainger, Jonathan

    2013-01-01

    How do we map the rapid input of spoken language onto phonological and lexical representations over time? Attempts at psychologically-tractable computational models of spoken word recognition tend either to ignore time or to transform the temporal input into a spatial representation. TRACE, a connectionist model with broad and deep coverage of speech perception and spoken word recognition phenomena, takes the latter approach, using exclusively time-specific units at every level of representation. TRACE reduplicates featural, phonemic, and lexical inputs at every time step in a large memory trace, with rich interconnections (excitatory forward and backward connections between levels and inhibitory links within levels). As the length of the memory trace is increased, or as the phoneme and lexical inventory of the model is increased to a realistic size, this reduplication of time- (temporal position) specific units leads to a dramatic proliferation of units and connections, begging the question of whether a more efficient approach is possible. Our starting point is the observation that models of visual object recognition—including visual word recognition—have grappled with the problem of spatial invariance, and arrived at solutions other than a fully-reduplicative strategy like that of TRACE. This inspires a new model of spoken word recognition that combines time-specific phoneme representations similar to those in TRACE with higher-level representations based on string kernels: temporally independent (time invariant) diphone and lexical units. This reduces the number of necessary units and connections by several orders of magnitude relative to TRACE. Critically, we compare the new model to TRACE on a set of key phenomena, demonstrating that the new model inherits much of the behavior of TRACE and that the drastic computational savings do not come at the cost of explanatory power. PMID:24058349

  2. Process tracing og studiet af kausale mekanismer

    DEFF Research Database (Denmark)

    Beach, Derek

    2014-01-01

    This article contends that there are large methodological advantages in tracing mechanisms linking a given cause (or causes) with an outcome. Causal mechanisms are the theoretical process that link X and Y together. By tracing mechanisms, we gain knowledge about how X contributes to produce Y....... There are three advantages of PT. First, PT enables us to make strong inferences about X being causally related to Y because we gain detailed within-case evidence of the process that links X and Y together. Second, we gain a better understanding of the process linking the two. Finally, when tracing mechanisms we...

  3. Trace elements as paradigms of developmental neurotoxicants

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Herz, Katherine T

    2015-01-01

    Trace elements have contributed unique insights into developmental neurotoxicity and serve as paradigms for such adverse effects. Many trace elements are retained in the body for long periods and can be easily measured to assess exposure by inexpensive analytical methods that became available...... neurotoxicants that provide a reference for other substances that may have similar adverse effects. Less evidence is available on manganese, fluoride, and cadmium, but experience from the former trace elements suggest that, with time, adverse effects are likely to be documented at exposures previously thought...

  4. Remediation using trace element humate surfactant

    Science.gov (United States)

    Riddle, Catherine Lynn; Taylor, Steven Cheney; Bruhn, Debra Fox

    2016-08-30

    A method of remediation at a remediation site having one or more undesirable conditions in which one or more soil characteristics, preferably soil pH and/or elemental concentrations, are measured at a remediation site. A trace element humate surfactant composition is prepared comprising a humate solution, element solution and at least one surfactant. The prepared trace element humate surfactant composition is then dispensed onto the remediation site whereby the trace element humate surfactant composition will reduce the amount of undesirable compounds by promoting growth of native species activity. By promoting native species activity, remediation occurs quickly and environmental impact is minimal.

  5. Process tracing methods: foundation and guidelines

    DEFF Research Database (Denmark)

    Beach, Derek; Pedersen, Rasmus Brun

    Derek Beach and Rasmus Brun Pedersen have written the first practical guide for using process tracing in social science research. The book introduces a more refined definition of what process tracing methods are, differentiating it into three variants, showing the uses and limitations of each...... a set of tools for how the three variants of process tracing methods can be used in research, introducing a set of practical guidelines for each stage of the research process (working with theories, developing empirical tests, working with evidence, and case selection strategies, nesting case studies...

  6. Mass spectrometric examinations of Hungarian triassic dolomites

    International Nuclear Information System (INIS)

    Vitalis, Gy.; Kada I-ne

    1982-01-01

    A limited number of mass spectrometric investigations (viz.:57) of representative rock types were applied both in the research work of geology and the mining for the industry of building materials of Hungary. Tabulated results covering all rock types and all stratigraphic levels of the Hungarian Triassic are given. Sr, Mn, Ti and Cr trace elements had the highest occurrence and Zn, Y or Pb, Ba, V or Cu, depending on the genetical type of the rock studied, has relatively higher concentrations as well. The results of the examinations of Hungarian Triassic dolomites were discussed according to genetical types, all represented by a small level of trace elements. (Sz.J.)

  7. Effect of ionic composition of meteor trace on its relaxation time in the presence of external electric field

    International Nuclear Information System (INIS)

    Klimov, M.P.; Lyatskaya, A.M.

    1989-01-01

    The dissipation of meteor trace as the function of ionic composition and electric field is investigated numerically. Critical values of electric field E 1 and E 2 are determined. At E 1 the dissipation process is similar to the diffusion one; lifetimes are proportional to diffusion coefficient. At E 1 2 - the dissipation process falls into two phases with different character of lifetime dependence on meteor trace mass. At E>E 2 lifetime does not depend on the electric field

  8. Geochemistry of environmentally sensitive trace elements in Permian coals from the Huainan coalfield, Anhui, China

    Science.gov (United States)

    Chen, J.; Liu, Gaisheng; Jiang, M.; Chou, C.-L.; Li, H.; Wu, B.; Zheng, Lingyun; Jiang, D.

    2011-01-01

    To study the geochemical characteristics of 11 environmentally sensitive trace elements in the coals of the Permian Period from the Huainan coalfield, Anhui province, China, borehole samples of 336 coals, two partings, and four roof and floor mudstones were collected from mineable coal seams. Major elements and selected trace elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and hydride generation atomic absorption spectrometry (HAAS). The depositional environment, abundances, distribution, and modes of occurrence of trace elements were investigated. Results show that clay and carbonate minerals are the principal inorganic constituents in the coals. A lower deltaic plain, where fluvial channel systems developed successively, was the likely depositional environment of the Permian coals in the Huainan coalfield. All major elements have wider variation ranges than those of Chinese coals except for Mg and Fe. The contents of Cr, Co, Ni, and Se are higher than their averages for Chinese coals and world coals. Vertical variations of trace elements in different formations are not significant except for B and Ba. Certain roof and partings are distinctly higher in trace elements than underlying coal bench samples. The modes of occurrence of trace elements vary in different coal seams as a result of different coal-forming environments. Vanadium, Cr, and Th are associated with aluminosilicate minerals, Ba with carbonate minerals, and Cu, Zn, As, Se, and Pb mainly with sulfide minerals. ?? 2011 Elsevier B.V.

  9. Using column experiments to examine transport of As and other trace elements released from poultry litter: Implications for trace element mobility in agricultural watersheds.

    Science.gov (United States)

    Oyewumi, Oluyinka; Schreiber, Madeline E

    2017-08-01

    Trace elements are added to poultry feed to control infection and improve weight gain. However, the fate of these trace elements in poultry litter is poorly understood. Because poultry litter is applied as fertilizer in many agricultural regions, evaluation of the environmental processes that influence the mobility of litter-derived trace elements is critical for predicting if trace elements are retained in soil or released to water. This study examined the effect of dissolved organic carbon (DOC) in poultry litter leachate on the fate and transport of litter-derived elements (As, Cu, P and Zn) using laboratory column experiments with soil collected from the Delmarva Peninsula (Mid-Atlantic, USA), a region of intense poultry production. Results of the experiments showed that DOC enhanced the mobility of all of the studied elements. However, despite the increased mobility, 60-70% of Zn, As and P mass was retained within the soil. In contrast, almost all of the Cu was mobilized in the litter leachate experiments, with very little retention in soil. Overall, our results demonstrate that the mobility of As, Cu, Zn and P in soils which receive poultry litter application is strongly influenced by both litter leachate composition, specifically organic acids, and adsorption to soil. Results have implications for understanding fate and transport of trace elements released from litter application to soil water and groundwater, which can affect both human health and the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Mass metrology

    CERN Document Server

    Gupta, S V

    2012-01-01

    This book presents the practical aspects of mass measurements. Concepts of gravitational, inertial and conventional mass and details of the variation of acceleration of gravity are described. The Metric Convention and International Prototype Kilogram and BIPM standards are described. The effect of change of gravity on the indication of electronic balances is derived with respect of latitude, altitude and earth topography. The classification of weights by OIML is discussed. Maximum permissible errors in different categories of weights prescribed by national and international organizations are p

  11. Process Upsets Involving Trace Contaminant Control Systems

    Science.gov (United States)

    Graf, John C.; Perry, Jay; Wright, John; Bahr, Jim

    2000-01-01

    Paradoxically, trace contaminant control systems that suffer unexpected upsets and malfunctions can release hazardous gaseous contaminants into a spacecraft cabin atmosphere causing potentially serious toxicological problems. Trace contaminant control systems designed for spaceflight typically employ a combination of adsorption beds and catalytic oxidation reactors to remove organic and inorganic trace contaminants from the cabin atmosphere. Interestingly, the same design features and attributes which make these systems so effective for purifying a spacecraft's atmosphere can also make them susceptible to system upsets. Cabin conditions can be contributing causes of phenomena such as adsorbent "rollover" and catalyst poisoning can alter a systems performance and in some in stances release contamination into the cabin. Evidence of these phenomena has been observed both in flight and during ground-based tests. The following discussion describes specific instances of system upsets found in trace contaminant control systems, groups these specific upsets into general hazard classifications, and recommends ways to minimize these hazards.

  12. Pre-LBA TRACE-A Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains atmospheric chemistry and meteorological data from the NASA Transport and Atmospheric Chemistry near the Equator-Atlantic (TRACE-A) field...

  13. Trace element contamination in feather and tissue samples from Anna’s hummingbirds

    Science.gov (United States)

    Mikoni, Nicole A.; Poppenga, Robert H.; Ackerman, Joshua T.; Foley, Janet E.; Hazlehurst, Jenny; Purdin, Güthrum; Aston, Linda; Hargrave, Sabine; Jelks, Karen; Tell, Lisa A.

    2017-01-01

    Trace element contamination (17 elements; Be, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, Hg, Tl, and Pb) of live (feather samples only) and deceased (feather and tissue samples) Anna's hummingbirds (Calypte anna) was evaluated. Samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS; 17 elements) and atomic absorption spectrophotometry (Hg only). Mean plus one standard deviation (SD) was considered the benchmark, and concentrations above the mean + 1 SD were considered elevated above normal. Contour feathers were sampled from live birds of varying age, sex, and California locations. In order to reduce thermal impacts, minimal feathers were taken from live birds, therefore a novel method was developed for preparation of low mass feather samples for ICP-MS analysis. The study found that the novel feather preparation method enabled small mass feather samples to be analyzed for trace elements using ICP-MS. For feather samples from live birds, all trace elements, with the exception of beryllium, had concentrations above the mean + 1 SD. Important risk factors for elevated trace element concentrations in feathers of live birds were age for iron, zinc, and arsenic, and location for iron, manganese, zinc, and selenium. For samples from deceased birds, ICP-MS results from body and tail feathers were correlated for Fe, Zn, and Pb, and feather concentrations were correlated with renal (Fe, Zn, Pb) or hepatic (Hg) tissue concentrations. Results for AA spectrophotometry analyzed samples from deceased birds further supported the ICP-MS findings where a strong correlation between mercury concentrations in feather and tissue (pectoral muscle) samples was found. These study results support that sampling feathers from live free-ranging hummingbirds might be a useful, non-lethal sampling method for evaluating trace element exposure and provides a sampling alternative since their small body size limits traditional sampling of blood and tissues. The

  14. Trace element analysis of nail polishes

    International Nuclear Information System (INIS)

    Misra, G.; Mittal, V.K.; Sahota, H.S.

    1999-01-01

    Instrumental neutron activation analysis (INAA) technique was used to measure the concentrations of various trace elements in nail polishes of popular Indian and foreign brands. The aim of the present experiment was to see whether trace elements could distinguish nail polishes of different Indian and foreign brands from forensic point of view. It was found that cesium can act as a marker to differentiate foreign and Indian brands. (author)

  15. Trace Selection for Improved WLAN Monitoring

    OpenAIRE

    Sammarco, Matteo; Elias Mitre Campista, Miguel; Dias De Amorim, Marcelo

    2013-01-01

    International audience; Existing measurement techniques for IEEE 802.11-based networks assume that the higher the density of monitors in the target area, the higher the quality of the measure. This assumption is, however, too strict if we consider the cost involved in monitor installation and the necessary time to collect and merge all traces. In this paper, we investigate the balance between number of traces and completeness of collected data. We propose a method based on similarity to rank ...

  16. Detecting Traces of Life in the Plume of Enceladus

    Science.gov (United States)

    Krolikowski, Daniel M.; Lunine, Jonathan I.

    2015-01-01

    Saturn's moon Enceladus presents one of the most promising bodies in the solar system on which to detect (at least traces of) extraterrestrial life. We present a study of biomarkers in the plume. A variety of potential biomarkers were considered and their applicability to the plume was assessed. Our study focused primarily on the relative abundances of hydrocarbons to methane, and amino acids. Concentrations of these biomarkers were estimated by combining data from studies of methanogenic and hydrothermal communities with a plume density model. We studied mass spectrometry as a possible means to detect these indicators of life. We performed a parameterized study by considering mass spectrometers with a sensitivity of 10, 100, and 1000 times that of Cassini's mass spectrometer. Promisingly, the concentration of biogenic hydrocarbons is around an order of magnitude higher than the detection threshold of the most sensitive mass spectrometer we considered. Therefore, analysis of such hydrocarbons on a future mission is a promising approach to detecting biochemical processes within Enceladus.

  17. Screening for trace explosives by AccuTOF™-DART®: an in-depth validation study.

    Science.gov (United States)

    Sisco, Edward; Dake, Jeffrey; Bridge, Candice

    2013-10-10

    Ambient ionization mass spectrometry is finding increasing utility as a rapid analysis technique in a number of fields. In forensic science specifically, analysis of many types of samples, including drugs, explosives, inks, bank dye, and lotions, has been shown to be possible using these techniques [1]. This paper focuses on one type of ambient ionization mass spectrometry, Direct Analysis in Real Time Mass Spectrometry (DART-MS or DART), and its viability as a screening tool for trace explosives analysis. In order to assess viability, a validation study was completed which focused on the analysis of trace amounts of nitro and peroxide based explosives. Topics which were studied, and are discussed, include method optimization, reproducibility, sensitivity, development of a search library, discrimination of mixtures, and blind sampling. Advantages and disadvantages of this technique over other similar screening techniques are also discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Stellar Masses

    Indian Academy of Sciences (India)

    later stages of evolution into a red giant differs considerably. It may lead to the formation of a white dwarf via a planetary nebula phase (for stars like the Sun) or the formation of a neutron star via a supernova explosion (for massive stars). The exact course is decided by the mass again. The energy produced is proportional to ...

  19. Mass spectrometry

    DEFF Research Database (Denmark)

    Nyvang Hartmeyer, Gitte; Jensen, Anne Kvistholm; Böcher, Sidsel

    2010-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently being introduced for the rapid and accurate identification of bacteria. We describe 2 MALDI-TOF MS identification cases - 1 directly on spinal fluid and 1 on grown bacteria. Rapidly obtained...

  20. Trace metallic elements in Helix aspersa terrestrial snails of a semiarid ecosystem

    International Nuclear Information System (INIS)

    Gaso P, M.I.; Segovia, N.; Zarazua, G.; Montes, F.; Morton, O.; Armienta, M.A.; Hernandez, E.

    2001-01-01

    The concentration of some major elements and traces in soil samples and of Helix aspersa eatable terrestrial snails were analysed at the Radioactive Wastes Storage Center (CADER) and in other reference sites. The methodology includes the use of an atomic absorption spectrophotometer, an X-ray fluorescence equipment and an Icp-mass spectroscope. The concentrations of some toxic elements (Ba, Cd, Cr, Ni, Pb and V) in the soft tissue of the snails were greater than the toxic levels reported in the literature for such trace elements. The snails compared with another wild eatable foods present transfer coefficients soil-snail high relatively. (Author)

  1. Foundations for Survivable System Development: Service Traces, Intrusion Traces, and Evaluation Models

    National Research Council Canada - National Science Library

    Linger, Richard

    2001-01-01

    .... On the system side, survivability specifications can be defined by essential-service traces that map essential-service workflows, derived from user requirements, into system component dependencies...

  2. Bulk viscosity and trace anomaly in the massive Gross-Neveu model

    International Nuclear Information System (INIS)

    Fernandez-Fraile, Daniel

    2011-01-01

    I present preliminary results concerning the calculation of the bulk viscosity for the Gross-Neveu model in the large N limit with a non-zero bare fermion mass and vanishing chemical potential. This finite mass breaks the integrability of the model and allows for transport of momentum in a non-equilibrium situation. By making this mass arbitrarily small, we can explicitly study the relationship between a peak in the trace anomaly and the bulk viscosity. Since the Gross-Neveu model resembles QCD in many essential aspects, its study allows us to extrapolate some of the conclusions obtained to this physically relevant theory.

  3. Mass distribution for the two-photon channel

    CERN Multimedia

    ATLAS, collaboration

    2012-01-01

    Mass distribution for the two-photon channel. The strongest evidence for this new particle comes from analysis of events containing two photons. The smooth dotted line traces the measured background from known processes. The solid line traces a statistical fit to the signal plus background. The new particle appears as the excess around 126.5 GeV. The full analysis concludes that the probability of such a peak is three chances in a million.

  4. Trace Element Analysis of Selenium

    International Nuclear Information System (INIS)

    Soliman, M.S.A.

    2010-01-01

    The present thesis divided into four chapters as follows:Chapter (1):This chapter contains an introduction on different oxidation states of organic and inorganic species for selenium in environmental and biological samples, the process for separation of selenium from these samples and the importance of selenium as a component for these samples. Also gives notes about the techniques which are used in the elemental analysis for selenium species and the detection limits for selenium in these techniques, selenium species in human body and the importance of these species in protecting the body from the different types of cancer and the sources of selenium in environmental samples (soil and water) and distribution levels of selenium in these samples.Chapter (2):This chapter is divided into two parts :The first part deals with the sample collection process for environmental samples (underground water, soil) and the wet digestion ( microwave digestion ) process of soil samples. It also contains the theory of work of the closed microwave digestion system.The second part contains detailed information concerning the theoretical considerations of the used analytical techniques. These techniques include Hydride generation - Atomic Absorption Spectrometer (HG-AAS), Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and Neutron Activation Analysis (NAA).Chapter (3): This chapter includes the methods of sampling, sample preparation, and sample digesition. The measures of quality assurance are disscused in this chapter. It describes in details the closed microwave digestion technique and the analytical methods used in this study which are present in Central Laboratory for Elemental and Isotopic Analysis (CLEIA) and the Egypt Second Research Reactor (ETRR-2). The described techniques are Atomic Absorption Spectrometer (AAS 6 vario, Analytical Jena GmbH, Germany), JMS-PLASMAX2 Mass Spectrometer (ICP-MS) and the Egypt Second Research Reactor (NAA).

  5. Trace element abundances in major minerals of Late Permian coals from southwestern Guizhou province, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junying; Zheng, Chuguang; Liu, Jing [National Laboratory of Coal Combustion, Institute of Energy Science and Engineering, Huazhong University of Science and Technology, 430074 Wuhan (China); Ren, Deyi [China University of Mining and Technology, 100083 Beijing (China); Zeng, Rongshu [Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing (China); Chou, Chen-Lin [Illinois State Geological Survey, 615 East Peabody Drive, 61820 Champaign, IL (United States)

    2002-12-01

    Fourteen samples of minerals were separated by handpicking from Late Permian coals in southwestern Guizhou province, China. These 14 minerals were nodular pyrite, massive recrystallized pyrite, pyrite deposited from low-temperature hydrothermal fluid and from ground water; clay minerals; and calcite deposited from low-temperature hydrothermal fluid and from ground water. The mineralogy, elemental composition, and distribution of 33 elements in these samples were studied by optical microscopy, scanning electron microscope equipped with energy-dispersive X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), cold-vapor atomic absorption spectrometry (CV-AAS), atomic fluorescence spectrometry (AFS), inductively coupled-plasma mass spectrometry (ICP-MS), and ion-selective electrode (ISE). The results show that various minerals in coal contain variable amounts of trace elements. Clay minerals have high concentrations of Ba, Be, Cs, F, Ga, Nb, Rb, Th, U, and Zr. Quartz has little contribution to the concentration of trace elements in bulk coal. Arsenic, Mn, and Sr are in high concentrations in calcite. Pyrite has high concentrations of As, Cd, Hg, Mo, Sb, Se, Tl, and Zn. Different genetic types of calcite in coal can accumulate different trace elements; for example Ba, Co, Cr, Hg, Ni, Rb, Sn, Sr, and Zn are in higher concentrations in calcite deposited from low-temperature hydrothermal fluid than in that deposited from ground water. Furthermore, the concentrations of some trace elements are quite variable in pyrite; different genetic types of pyrites (Py-A, B, C, D) have different concentrations of trace elements, and the concentrations of trace elements are also different in pyrite of low-temperature hydrothermal origin collected from different locations. The study shows that elemental concentration is rather uniform in a pyrite vein. There are many micron and submicron mosaic pyrites in a pyrite vein, which is enriched in some trace elements, such as As and Mo. The

  6. Infant word recognition: Insights from TRACE simulations☆

    Science.gov (United States)

    Mayor, Julien; Plunkett, Kim

    2014-01-01

    The TRACE model of speech perception (McClelland & Elman, 1986) is used to simulate results from the infant word recognition literature, to provide a unified, theoretical framework for interpreting these findings. In a first set of simulations, we demonstrate how TRACE can reconcile apparently conflicting findings suggesting, on the one hand, that consonants play a pre-eminent role in lexical acquisition (Nespor, Peña & Mehler, 2003; Nazzi, 2005), and on the other, that there is a symmetry in infant sensitivity to vowel and consonant mispronunciations of familiar words (Mani & Plunkett, 2007). In a second series of simulations, we use TRACE to simulate infants’ graded sensitivity to mispronunciations of familiar words as reported by White and Morgan (2008). An unexpected outcome is that TRACE fails to demonstrate graded sensitivity for White and Morgan’s stimuli unless the inhibitory parameters in TRACE are substantially reduced. We explore the ramifications of this finding for theories of lexical development. Finally, TRACE mimics the impact of phonological neighbourhoods on early word learning reported by Swingley and Aslin (2007). TRACE offers an alternative explanation of these findings in terms of mispronunciations of lexical items rather than imputing word learning to infants. Together these simulations provide an evaluation of Developmental (Jusczyk, 1993) and Familiarity (Metsala, 1999) accounts of word recognition by infants and young children. The findings point to a role for both theoretical approaches whereby vocabulary structure and content constrain infant word recognition in an experience-dependent fashion, and highlight the continuity in the processes and representations involved in lexical development during the second year of life. PMID:24493907

  7. Temporally rendered automatic cloud extraction (TRACE) system

    Science.gov (United States)

    Bodrero, Dennis M.; Yale, James G.; Davis, Roger E.; Rollins, John M.

    1999-10-01

    Smoke/obscurant testing requires that 2D cloud extent be extracted from visible and thermal imagery. These data are used alone or in combination with 2D data from other aspects to make 3D calculations of cloud properties, including dimensions, volume, centroid, travel, and uniformity. Determining cloud extent from imagery has historically been a time-consuming manual process. To reduce time and cost associated with smoke/obscurant data processing, automated methods to extract cloud extent from imagery were investigated. The TRACE system described in this paper was developed and implemented at U.S. Army Dugway Proving Ground, UT by the Science and Technology Corporation--Acuity Imaging Incorporated team with Small Business Innovation Research funding. TRACE uses dynamic background subtraction and 3D fast Fourier transform as primary methods to discriminate the smoke/obscurant cloud from the background. TRACE has been designed to run on a PC-based platform using Windows. The PC-Windows environment was chosen for portability, to give TRACE the maximum flexibility in terms of its interaction with peripheral hardware devices such as video capture boards, removable media drives, network cards, and digital video interfaces. Video for Windows provides all of the necessary tools for the development of the video capture utility in TRACE and allows for interchangeability of video capture boards without any software changes. TRACE is designed to take advantage of future upgrades in all aspects of its component hardware. A comparison of cloud extent determined by TRACE with manual method is included in this paper.

  8. Pancreatic cancer risk and levels of trace elements

    Science.gov (United States)

    Amaral, André F. S.; Porta, Miquel; Silverman, Debra T.; Milne, Roger L.; Kogevinas, Manolis; Rothman, Nathaniel; Cantor, Kenneth P.; Jackson, Brian P.; Pumarega, José A.; López, Tomàs; Carrato, Alfredo; Guarner, Luisa; Real, Francisco X.; Malats, Núria

    2011-01-01

    Background and aims Knowledge on the etiology of exocrine pancreatic cancer (EPC) is scant. The best established risk factor for EPC is tobacco smoking. Among other carcinogens, tobacco contains cadmium, a metal previously associated with an increased risk of EPC. We evaluated the association between concentrations of trace elements in toenails and EPC risk. Methods The study included 118 EPC cases and 399 hospital controls from Eastern Spain. Levels of twelve trace elements were determined in toenail samples by inductively coupled plasma - mass spectrometry. Odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for potential confounders, were calculated using logistic regression. Results Significantly increased risks of EPC were observed among subjects whose concentrations of cadmium (OR=3.58, 95%CI 1.86–6·88; Ptrend=5×10−6), arsenic (OR=2.02, 95%CI 1.08–3.78; Ptrend=0.009), and lead (OR=6.26, 95%CI 2.71–14.47; Ptrend=3×10−5) were in the highest quartile. High concentrations of selenium (OR=0.05, 95%CI 0.02–0.15; Ptrend=8×10−11) and nickel (OR=0.27, 95%CI 0.12–0.59; Ptrend=2×10−4) were inversely associated with risk of EPC. Conclusion We report novel associations of lead, nickel, and selenium toenail concentrations with pancreas cancer risk. Furthermore, results confirm previous associations with cadmium and arsenic. These novel findings, if replicated in independent studies, would point to an important role of trace elements in pancreatic carcinogenesis. PMID:22184070

  9. TXRF analysis of trace metals in thin silicon nitride films

    International Nuclear Information System (INIS)

    Vereecke, G.; Arnauts, S.; Verstraeten, K.; Schaekers, M.; Heyrts, M.M.

    2000-01-01

    As critical dimensions of integrated circuits continue to decrease, high dielectric constant materials such as silicon nitride are being considered to replace silicon dioxide in capacitors and transistors. The achievement of low levels of metal contamination in these layers is critical for high performance and reliability. Existing methods of quantitative analysis of trace metals in silicon nitride require high amounts of sample (from about 0.1 to 1 g, compared to a mass of 0.2 mg for a 2 nm thick film on a 8'' silicon wafer), and involve digestion steps not applicable to films on wafers or non-standard techniques such as neutron activation analysis. A novel approach has recently been developed to analyze trace metals in thin films with analytical techniques currently used in the semiconductor industry. Sample preparation consists of three steps: (1) decomposition of the silicon nitride matrix by moist HF condensed at the wafer surface to form ammonium fluosilicate. (2) vaporization of the fluosilicate by a short heat treatment at 300 o C. (3) collection of contaminants by scanning the wafer surface with a solution droplet (VPD-DSC procedure). The determination of trace metals is performed by drying the droplet on the wafer and by analyzing the residue by TXRF, as it offers the advantages of multi-elemental analysis with no dilution of the sample. The lower limits of detection for metals in 2 nm thick films on 8'' silicon wafers range from about 10 to 200 ng/g. The present study will focus on the matrix effects and the possible loss of analyte associated with the evaporation of the fluosilicate salt, in relation with the accuracy and the reproducibility of the method. The benefits of using an internal standard will be assessed. Results will be presented from both model samples (ammonium fluoride contaminated with metallic salts) and real samples (silicon nitride films from a production tool). (author)

  10. Temperature and Concentration Traces of Spray Flows During Motion in a Flame

    Directory of Open Access Journals (Sweden)

    Antonov Dmitry V.

    2016-01-01

    Full Text Available Heat and mass transfer models are developed on the base of experimental data and using Ansys Fluent software. These models allow prediction of the temperature and concentration traces of droplets. Transfer mechanisms of water droplets from different flames of flammable liquid (ethanol, kerosene И benzine with temperature gases 450–850 К are analyzed. The paper considers aerosol flows with droplets sizes of 0.04–0.4 mm and concentration of 3.8·10-5 –10.3·10-5 m3 of droplets/m3 of gas. The maximum gas temperature reduction in the trace of a moving liquid is ranged from 850 K to 600 K. The times of keeping the low temperature of the gas-vapor mixture in the droplets trace are from 13 s to 25 s relative to the initial gas temperature.

  11. Contents of trace elements in blood of healthy old people assayed by ICP-MS

    International Nuclear Information System (INIS)

    Wen Xinyu; Tong Hongli; Wang Ling; Zhou Heping; Tian Yaping

    2008-01-01

    To investigate the levels of 11 trace elements in serum of healthy old people to provide scientific basis for prevention and treatment of geriatric diseases, the serum were separated from blood samples according to standard procedure. The serum samples were underwent digestion, elimination of nitric acid, volume fixation and then assayed by inductively coupled plasma mass spectrometry. The results showed that the contents of Al in elderly people's serum is higher than those in young people (P<0.01), while the contents of V, Cr, Cu and Se in elderly people's serum were lower than those in young people (P<0.05). There were no significant differences in other trace elements between two groups. The contents of some trace elements in elderly people's serum changed significantly. (authors)

  12. TRACE ELEMENTS IN FRUIT AND VEGETABLE

    Directory of Open Access Journals (Sweden)

    Stefania Papa

    2009-12-01

    Full Text Available The concentration of six different trace metals [vanadium (V, nickel (Ni, chromium (Cr,  lead (Pb, copper (Cu and cadmium (Cd] were determined in various fruit and vegetables [peach (Prunus persica L., plum (Prunus domestica L., tomato (Solanum lycopersicum L., courgette or marrow (Cucurbita pepo L. and lettuce (Lactuca sativa L.] provided by diverse farms. Metal distribution was also separately evaluated, in skin and pulp, where it was possible. Their contributions to human daily intake of trace metals were investigated. Atomic absorption spectrometry was used to determine the concentrations of these metals in the fruit and vegetables. All traces of elements tested in peaches and tomatoes were higher in the skin than in the pulp except for Cd in the peaches; all traces of elements tested in plums and marrows were higher in the pulp than in the skin. The concentrations of Pb and Cd in lettuce were 1.3 and 2.7 times above the permissible levels, respectively. It is concluded that the regular monitoring of food trace metals is very important to prevent diseases that depend on their excessive accumulation in the human food chain.

  13. [Distribution Characteristics and Source Analysis of Dustfall Trace Elements During Winter in Beijing].

    Science.gov (United States)

    Xiong, Qiu-lin; Zhao, Wen-ji; Guo, Xiao-yu; Chen, Fan-tao; Shu, Tong-tong; Zheng, Xiao-xia; Zhao, Wen-hui

    2015-08-01

    The dustfall content is one of the evaluation indexes of atmospheric pollution. Trace elements especially heavy metals in dustfall can lead to risks to ecological environment and human health. In order to study the distribution characteristics of trace elements, heavy metals pollution and their sources in winter atmospheric dust, 49 dustfall samples were collected in Beijing City and nearby during November 2013 to March 2014. Then the contents (mass percentages) of 40 trace elements were measured by Elan DRC It type inductively coupled plasma mass (ICP-MS). Test results showed that more than half of the trace elements in the dust were less than 10 mg x kg(-1); about a quarter were between 10-100 mg x kg-1); while 7 elements (Pb, Zr, Cr, Cu, Zn, Sr and Ba) were more than 100 mg x kg(-1). The contents of Pb, Cu, Zn, Bi, Cd and Mo of winter dustfall in Beijing city.were respectively 4.18, 4.66, 5.35, 6.31, 6.62, and 8.62 times as high as those of corresponding elements in the surface soil in the same period, which went beyond the soil background values by more than 300% . The contribution of human activities to dustfall trace heavy metals content in Beijing city was larger than that in the surrounding region. Then sources analysis of dustfall and its 20 main trace elements (Cd, Mo, Nb, Ga, Co, Y, Nd, Li, La, Ni, Rb, V, Ce, Pb, Zr, Cr, Cu, Zn, Sr, Ba) was conducted through a multi-method analysis, including Pearson correlation analysis, Kendall correlation coefficient analysis and principal component analysis. Research results indicated that sources of winter dustfall in Beijing city were mainly composed of the earth's crust sources (including road dust, construction dust and remote transmission of dust) and the burning of fossil fuels (vehicle emissions, coal combustion, biomass combustion and industrial processes).

  14. Simulation of reflooding on two parallel heated channel by TRACE

    Energy Technology Data Exchange (ETDEWEB)

    Zakir, Md. Ghulam [Department of Nuclear Engineering, Chalmers University of Technology, Gothenburg (Sweden)

    2016-07-12

    In case of Loss-Of-Coolant accident (LOCA) in a Boiling Water Reactor (BWR), heat generated in the nuclear fuel is not adequately removed because of the decrease of the coolant mass flow rate in the reactor core. This fact leads to an increase of the fuel temperature that can cause damage to the core and leakage of the radioactive fission products. In order to reflood the core and to discontinue the increase of temperature, an Emergency Core Cooling System (ECCS) delivers water under this kind of conditions. This study is an investigation of how the power distribution between two channels can affect the process of reflooding when the emergency water is injected from the top of the channels. The peak cladding temperature (PCT) on LOCA transient for different axial level is determined as well. A thermal-hydraulic system code TRACE has been used. A TRACE model of the two heated channels has been developed, and three hypothetical cases with different power distributions have been studied. Later, a comparison between a simulated and experimental data has been shown as well.

  15. ICP -MS determination of trace element in vegetable modificate fats

    International Nuclear Information System (INIS)

    Toncheva, Galya K.; Georgieva, Deana L.; Antova, Ginka A.; Merdzhanov, Pavel

    2014-01-01

    Tree types of hydrogenated fats which are used in the industry were tested. The initial trace element content was determined and also its changes during the heat treatment due to short -term or longer stay of the fats in the production container from chrome -nickel steel. Using inductively -coupled plasma -mass spectrometry (ICP MS) the total quantity of the selected metals in the fats was determined: Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Sn and Pb. Was investigated the migration kinetics of Fe and Cr in coating and filling fats and fatty acid composition of the fats at the beginning and end of the observation. Unacceptable changes were not found in the organoleptic characteristics of the fats, resulting from the migration of metals. The amount of the tested toxic metals does not exceed the limit value. An exception is the increased amount of copper in two and nickel in the tree types of fats . Key words: ICP -MS, trace element, hydrogenated fats

  16. Trace metal seasonal variations in Texas marine sediments

    Science.gov (United States)

    Holmes, C.W.

    1986-01-01

    Trace elements in coastal environments are derived from three major sources: (1) the bordering watershed; (2) the offshore marine environment; and (3) industrial and/or urban effluent. The site of deposition, however, is controlled by physical and chemical processes in the coastal zone. In many cases, these processes are controlled by climate and can vary seasonally. In the harbor at Corpus Christi, Texas, the summer climate creates an oxygen-poor environment in the water column near the sediment-water interface. This causes chalcophilic metals to precipitate from the water, resulting in high concentrations in the sediments near the source. During the winter, turbulence created by strong winds causes the entire water mass to become aerated and oxidizing, and remobilization of some metals results. In addition, this turbulence accelerates circulation which transports the metal-enriched waters from the harbor. On the outer continental shelf of south Texas, the infaunal activity varies seasonally with bottom water temperatures. As this infaunal activity has an effect on the chemical environment within the sediment near the sediment-water interface, the observed trace metal content at the interface also appears to change with the seasons. ?? 1986.

  17. Trace contaminant control simulation computer program, version 8.1

    Science.gov (United States)

    Perry, J. L.

    1994-01-01

    The Trace Contaminant Control Simulation computer program is a tool for assessing the performance of various process technologies for removing trace chemical contamination from a spacecraft cabin atmosphere. Included in the simulation are chemical and physical adsorption by activated charcoal, chemical adsorption by lithium hydroxide, absorption by humidity condensate, and low- and high-temperature catalytic oxidation. Means are provided for simulating regenerable as well as nonregenerable systems. The program provides an overall mass balance of chemical contaminants in a spacecraft cabin given specified generation rates. Removal rates are based on device flow rates specified by the user and calculated removal efficiencies based on cabin concentration and removal technology experimental data. Versions 1.0 through 8.0 are documented in NASA TM-108409. TM-108409 also contains a source file listing for version 8.0. Changes to version 8.0 are documented in this technical memorandum and a source file listing for the modified version, version 8.1, is provided. Detailed descriptions for the computer program subprograms are extracted from TM-108409 and modified as necessary to reflect version 8.1. Version 8.1 supersedes version 8.0. Information on a separate user's guide is available from the author.

  18. Copper stable isotopes to trace copper behavior in wetland systems.

    Science.gov (United States)

    Babcsányi, Izabella; Imfeld, Gwenaël; Granet, Mathieu; Chabaux, François

    2014-05-20

    Wetlands are reactive zones of the landscape that can sequester metals released by industrial and agricultural activities. Copper (Cu) stable isotope ratios (δ(65)Cu) have recently been used as tracers of transport and transformation processes in polluted environments. Here, we used Cu stable isotopes to trace the behavior of Cu in a stormwater wetland receiving runoff from a vineyard catchment (Alsace, France). The Cu loads and stable isotope ratios were determined in the dissolved phase, suspended particulate matter (SPM), wetland sediments, and vegetation. The wetland retained >68% of the dissolved Cu and >92% of the SPM-bound Cu, which represented 84.4% of the total Cu in the runoff. The dissolved Cu became depleted in (65)Cu when passing through the wetland (Δ(65)Cuinlet-outlet from 0.03‰ to 0.77‰), which reflects Cu adsorption to aluminum minerals and organic matter. The δ(65)Cu values varied little in the wetland sediments (0.04 ± 0.10‰), which stored >96% of the total Cu mass within the wetland. During high-flow conditions, the Cu flowing out of the wetland became isotopically lighter, indicating the mobilization of reduced Cu(I) species from the sediments and Cu reduction within the sediments. Our results demonstrate that the Cu stable isotope ratios may help trace Cu behavior in redox-dynamic environments such as wetlands.

  19. Critical Mass

    CERN Multimedia

    AUTHOR|(CDS)2070299

    2017-01-01

    Critical Mass is a cycling event typically held on the last Friday of every month; its purpose is not usually formalized beyond the direct action of meeting at a set location and time and traveling as a group through city or town streets on bikes. The event originated in 1992 in San Francisco; by the end of 2003, the event was being held in over 300 cities around the world. At CERN it is held once a year in conjunction with the national Swiss campaing "Bike to work".

  20. Selecting appropriate cases when tracing causal mechanisms

    DEFF Research Database (Denmark)

    Beach, Derek; Pedersen, Rasmus Brun

    2016-01-01

    The last decade has witnessed resurgence in the interest in studying the causal mechanisms linking causes and outcomes in the social sciences. This article explores the overlooked implications for case selection when tracing mechanisms using in-depth case studies. Our argument is that existing case...... selection guidelines are appropriate for research aimed at making cross-case claims about causal relationships, where case selection is primarily used to control for other causes. However, existing guidelines are not in alignment with case-based research that aims to trace mechanisms, where the goal...... is to unpack the causal mechanism between X and Y, enabling causal inferences to be made because empirical evidence is provided for how the mechanism actually operated in a particular case. The in-depth, within-case tracing of how mechanisms operate in particular cases produces what can be termed mechanistic...

  1. Correlation between bone mineral density and serum trace element contents of elderly males in Beijing urban area.

    Science.gov (United States)

    Wang, Liang; Yu, Haotian; Yang, Guohua; Zhang, Yan; Wang, Wenjiao; Su, Tianjiao; Ma, Weifeng; Yang, Fan; Chen, Liying; He, Li; Ma, Yuanzheng; Zhang, Yan

    2015-01-01

    Trace element levels are associated with the incidence of osteoporotic fractures, but related mechanisms remain unknown. Trace elements may interfere with growth, development and maintenance of bones. Therefore, we investigated whether plasma trace element levels are associated with bone mineral density in elderly males in Beijing. After epidemiologically investigating 91 elderly males with age ranging from 50 years to 80 years, we obtained a total of 30 healthy (group 1), 31 osteopoenic (group 2) and 30 osteoporotic (group 3) subjects. Blood was collected, and serum concentrations of trace elements were detected. Elderly males in the three groups were carefully matched in terms of body mass index. Iron, manganese, zinc, copper, selenium, cadmium and lead were analysed by inductively coupled plasma-mass spectrometry. Bone mineral density (BMD) was measured by QDR-2000 dual-energy X-ray absorptiometry. Correlation between BMD and serum element contents was analysed using SPSS16.0. The plasma levels of manganese, zinc, copper, selenium and lead were similar in all of the groups (P>0.05). Cadmium was significantly and negatively correlated with BMD of the lumbar vertebrae (Pbone levels of these trace elements to determine the relationship of these trace elements with osteoporosis.

  2. Trace Explosives Signatures from World War II Unexploded Undersea Ordnance

    Science.gov (United States)

    Darrach, M. R.; Chutjian, A.; Plett, G. A.

    1998-01-01

    Trace explosives signatures of TNT and DNT have been extracted from multiple sediment samples adjacent to unexploded undersea ordnance at Halifax Harbor, Canada. The ordnance was hurled into the harbor during a massive explosion some 50 years earlier, in 1945 after World War II had ended. Laboratory sediment extractions were made using the solid-phase microextraction (SPME) method in seawater and detection using the Reversal Electron Attachment Detection (READ) technique and, in the case of DNT, a commercial gas chromatograph/mass spectrometer (GC/MS). Results show that, after more than 50 years in the environment, ordnance that appeared to be physically intact gave good explosives signatures at the parts per billion level, whereas ordnance that had been cracked open during the explosion gave no signatures at the 10 parts per trillion sensitivity level. These measurements appear to provide the first reported data of explosives signatures from undersea unexploded ordnance.

  3. Real-Time Monitoring of Trace Gas Concentrations in Syngas

    Directory of Open Access Journals (Sweden)

    Herbig J.

    2013-08-01

    Full Text Available A Proton Transfer Reaction Mass Spectrometer (PTR-MS was used for the analysis of syngas in an industrial Fischer-Tropsch process. A PTR-MS can detect a variety of volatile organic and inorganic compounds in real-time and with high sensitivity. Together with a multiplexer, this allows for online (real-time monitoring of the trace contaminations at different stages of a Fischer-Tropsch process. Several volatile compounds, such as HCN, H2S, RSH, carbonyls, acids, alcohols and others have been measured in Syngas. This paper describes the setup to monitor syngas using PTR-MS and summarizes the result of this proof-of-principle project.

  4. Trace anomaly and invariance under transformation of units

    Science.gov (United States)

    Namavarian, Nadereh

    2017-05-01

    Paying attention to conformal invariance as the invariance under local transformations of units of measure, we take a conformal-invariant quantum field as a quantum matter theory in which one has the freedom to choose the values of units of mass, length, and time arbitrarily at each point. To be able to have this view, it is necessary that the background on which the quantum field is based be conformal invariant as well. Consequently, defining the unambiguous expectation value of the energy-momentum tensor of such a quantum field through the Wald renormalizing prescription necessitates breaking down the conformal symmetry of the background. Then, noticing the field equations suitable for describing the backreaction effect, we show that the existence of the "trace anomaly," known for indicating the brokenness of conformal symmetry in quantum field theory, can also indicate the above "gravitational" conformal symmetry brokenness.

  5. Tracking Oxidation During Transport of Trace Gases in Air from the Northern to Southern Hemisphere

    Science.gov (United States)

    Montzka, S. A.; Moore, F. L.; Atlas, E. L.; Parrish, D. D.; Miller, B. R.; Sweeney, C.; McKain, K.; Hall, B. D.; Siso, C.; Crotwell, M.; Hintsa, E. J.; Elkins, J. W.; Blake, D. R.; Barletta, B.; Meinardi, S.; Claxton, T.; Hossaini, R.

    2017-12-01

    Trace gas mole fractions contain the imprint of recent influences on an air mass such as sources, transport, and oxidation. Covariations among the many gases measured from flasks during ATom and HIPPO, and from the ongoing NOAA cooperative air sampling program enable recent influences to be identified from a wide range of sources including industrial activity, biomass burning, emissions from wetlands, and uptake by terrestrial ecosystems. In this work we explore the evolution of trace gas concentrations owing to atmospheric oxidation as air masses pass through the tropics, the atmospheric region with the highest concentrations of the hydroxyl radical. Variations in C2-C5 hydrocarbon concentrations downwind of source regions provide a measure of photochemical ageing in an air mass since emission, but they become less useful when tracking photochemical ageing as air is transported from the NH into the SH owing to their low mixing ratios, lifetimes that are very short relative to transport times, non-industrial sources in the tropics (e.g., biomass burning), and southern hemispheric sources. Instead, we consider a range of trace gases and trace gas pairs that provide a measure of photochemical processing as air transits the tropics. To be useful in this analysis, these trace gases would have lifetimes comparable to interhemispheric transport times, emissions arising from only the NH at constant relative magnitudes, and concentrations sufficient to allow precise and accurate measurements in both hemispheres. Some anthropogenically-emitted chlorinated hydrocarbons meet these requirements and have been measured during ATom, HIPPO, and from NOAA's ongoing surface sampling efforts. Consideration of these results and their implications for tracking photochemical processing in air as it is transported across the tropics will be presented.

  6. Trace element structure of the most widespread plants of genus PulmonariaFNx01

    Directory of Open Access Journals (Sweden)

    Dmitriy Kruglov

    2012-01-01

    Full Text Available Aim: The aim of this work was a comparative research of trace element structure of various organs of three Pulmonaria species. Materials and Methods: The aerial parts of the most widespread plants of genus Pulmonaria such as Pulmonaria officinalis L., Pulmonaria obscura Dumort. and Pulmonaria mollis Wulf. ex Hornem., which were collected in ending of flowering and were used as the research objects. The amount of trace elements (B, K, P, V, Ca, Co, Cu, Fe, Mg, Mn, Mo, Na, Si, Zn, Ag, Al, Ba, Br, Cr, I, Ni, Se, Sr, and Ti was determined by means of mass spectroscopy with inductively coupled plasma. Results: The data clustering has shown that floral shoots and rosellate leaves possess essentially various trace element status. At the same time, the trace elements′ status of organs of researched plants poorly depends on a taxonomic position of the plant. Thereupon, it is obvious that pharmacological activity is defined by organs of plants from which medicines were made, but not by a species of the used plant. Conclusions: The significant distinction in pharmacological activity of preparations depends on the trace elements′ status of used medicinal vegetative raw materials.

  7. Hair Trace Elements in Overweight and Obese Adults in Association with Metabolic Parameters.

    Science.gov (United States)

    Skalnaya, Margarita G; Skalny, Anatoly V; Grabeklis, Andrey R; Serebryansky, Eugeny P; Demidov, Vasily A; Tinkov, Alexey A

    2018-03-01

    The objective of the present study was to investigate the level of toxic and essential trace elements in hair of adult overweight and obese persons as well as its association with metabolic parameters. Hair trace element levels were assessed using inductively coupled plasma mass-spectrometry in 112 overweight and obese patients and 106 lean controls. Serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), glucose, uric acid (UA) levels, and cholinesterase (CE) and gamma-glutamyltransferase (GGT) activity were also assessed. Excessive body weight significantly affected hair trace element levels. In particular, hair Co (33%), Cu (13%), I (30%), Mg (2-fold), Mn (25%), Zn (17%), and Ni (21%) levels were lower, whereas Al (14%) and As levels were higher in comparison to those in the control group. Correlation analysis demonstrated the most significant correlations for hair Mg with body weight, BMI, systolic and diastolic blood pressure, and UA, and for hair Al with body weight, BMI, TC, glucose, TG, CE, GGT, and UA. Multiple regression analysis demonstrated that trace elements were not associated with TC and LDL-C levels neither in crude nor in adjusted models. In turn, crude and adjusted models accounted for 25 and 43% of serum TG variance. The most significant associations were observed for hair Al, Fe, Si, and V in adjusted model. The obtained data demonstrate that obesity-related metabolic disorders may be at least partially mediated by altered trace element and mineral levels.

  8. Comparative evaluation of trace elements in blood

    International Nuclear Information System (INIS)

    Goeij, J.J.M. de; Tjioe, P.S.; Pries, C.; Zwiers, J.H.L.

    1976-01-01

    The Interuniversitair Reactor Instituut and the Centraal Laboratorium TNO have carried out a common investigation on neutron-activation-analytical procedures for the determination of trace elements in blood. A comparative evaluation of five methods, destructive as well as non-destructive, is given. The sensitivity and reproducibility of the procedures are discussed. By combining some of the methods it is possible, starting with 1 ml blood, to give quantitative information on 14 important trace elements: antimony, arsenic, bromine, cadmium, cobalt, gold, copper, mercury, molybdenum, nickel, rubidium, selenium, iron and zinc. The methods have also been applied to sodium, chromium and potassium

  9. Isotope labeling eyed for tracing smoke particles

    International Nuclear Information System (INIS)

    Oagani, R.

    1988-01-01

    In an effort to track emissions from coal-fired power plants to their sources, researchers at the National Bureau of Standards and the University of Maryland are developing a technique that shows promise as a simple and definitive way of tracing smoke particles. The researchers say the method, which uses stable isotopes of rare-earth elements to tag emission particles (fly ash), may be the first one suitable for tracing fine particles over long distances. It would complement techniques based on tracer gases, which detect only gaseous components of stack emissions, not particles

  10. Paleoarchean trace fossils in altered volcanic glass

    OpenAIRE

    Staudigel, Hubert; Furnes, Harald; DeWit, Maarten

    2015-01-01

    The dawn of sustainable life on earth is preserved in the form of fossil or chemical evidence in ancient rock sequences, such as the Barberton Greenstone Belt in South Africa. Studies of sedimentary rocks offered a glimpse at life at the earth’s surface, and trace fossils in pillow lavas offered evidence for a potential deep biosphere back in time to the Paleoarchean. Recent data cast doubt on the biogenicity of these putative trace fossils, rejecting their potential in exploring a deep biosp...

  11. Trace element analysis in soy sauce. 2

    International Nuclear Information System (INIS)

    Haruyama, Yoichi; Saito, Manabu; Tomita, Michio; Yoshida, Koji.

    1994-01-01

    Trace elements in four kinds of soybean and three kinds of salt have been measured by means of in-air PIXE. In soybeans, which were made in Japan, America, Canada and China, six kinds of trace elements were detected, such as Mn, Fe, Ni, Cu, Zn and Br. The concentration of these elements varied depending on the place they were made. American soybean showed characteristic feature compared with other soybeans. As to the bromine concentration, American soybean contains ten times as much as Japanese one. In salts Br and Sr were detected. (author)

  12. Spatio-temporal variability of trace elements fingerprints in cockle (Cerastoderma edule) shells and its relevance for tracing geographic origin.

    Science.gov (United States)

    Ricardo, Fernando; Pimentel, Tânia; Génio, Luciana; Calado, Ricardo

    2017-06-14

    Understanding spatio-temporal variability of trace elements fingerprints (TEF) in bivalve shells is paramount to determine the discrimination power of this analytical approach and secure traceability along supply chains. Spatio-temporal variability of TEF was assessed in cockle (Cerastoderma edule) shells using inductively coupled plasma-mass spectrometry (ICP-MS). Four elemental ratios (Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca) were measured from the shells of specimens originating from eight different ecosystems along the Portuguese coast, as well as from four different areas, within one of them, over two consecutive years (2013 and 2014). TEF varied significantly in the shells of bivalves originating from the eight ecosystems surveyed in the present study. Linear discriminant function analyses assigned sampled cockles to each of the eight ecosystems with an average accuracy of 90%. Elemental ratios also displayed significant differences between the two consecutive years in the four areas monitored in the same ecosystem. Overall, while TEF displayed by cockle shells can be successfully used to trace their geographic origin, a periodical verification of TEF (>6 months and <1 year) is required to control for temporal variability whenever comparing specimens originating from the same area collected more than six months apart.

  13. Representativeness of laboratory sampling procedures for the analysis of trace metals in soil.

    Science.gov (United States)

    Dubé, Jean-Sébastien; Boudreault, Jean-Philippe; Bost, Régis; Sona, Mirela; Duhaime, François; Éthier, Yannic

    2015-08-01

    This study was conducted to assess the representativeness of laboratory sampling protocols for purposes of trace metal analysis in soil. Five laboratory protocols were compared, including conventional grab sampling, to assess the influence of sectorial splitting, sieving, and grinding on measured trace metal concentrations and their variability. It was concluded that grinding was the most important factor in controlling the variability of trace metal concentrations. Grinding increased the reproducibility of sample mass reduction by rotary sectorial splitting by up to two orders of magnitude. Combined with rotary sectorial splitting, grinding increased the reproducibility of trace metal concentrations by almost three orders of magnitude compared to grab sampling. Moreover, results showed that if grinding is used as part of a mass reduction protocol by sectorial splitting, the effect of sieving on reproducibility became insignificant. Gy's sampling theory and practice was also used to analyze the aforementioned sampling protocols. While the theoretical relative variances calculated for each sampling protocol qualitatively agreed with the experimental variances, their quantitative agreement was very poor. It was assumed that the parameters used in the calculation of theoretical sampling variances may not correctly estimate the constitutional heterogeneity of soils or soil-like materials. Finally, the results have highlighted the pitfalls of grab sampling, namely, the fact that it does not exert control over incorrect sampling errors and that it is strongly affected by distribution heterogeneity.

  14. Radiochemical neutron-activation analysis of uncertified ultra-trace rare earth elements in two biological certified reference materials

    International Nuclear Information System (INIS)

    Cao, Lei; Tian, Weizhi; Ni, Bangfa; Wang, Pingsheng; Zhang, Yangmei

    2002-01-01

    Radiochemical neutron activation analysis (RNAA) has been used for the determination of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) in two Chinese certified reference materials (CRM), GBW 08503 (wheat powder) and GBW 09101 (human hair). These determinations are important for possible certification of the above mentioned ultra-trace elements, so far not certified. A simple one-step (REE)F 3 precipitation was used. Chemical yields were determined for all relevant elements by means of tracer experiments. The two CRM were also analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) to compare the merits and drawbacks of these two major trace analytical techniques for these particular elements. RNAA was proven to be a reliable technique for ultra-trace analysis, especially in the certification of some ultra-trace elements. (orig.)

  15. Trace Elements in Human Nutrition and Health

    African Journals Online (AJOL)

    Trace Elements in Human Nutrition and Health, a report of a. World Heatth Organisation Expert Committee, contains material contributed by numerous experts consulted in different specialised fields, together with the conClusions reached and recommendations made by the Expert. Consultation. The nineteen nutritionally ...

  16. Conformal transformation, gauge fields and trace anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Alves, M.S.; Barcelos-Neto, J.

    1988-02-01

    In a recent work, Padmanabhan (1985 Class. Quant. Grav. 2 4105) showed an interesting way of constructing a general conformally invariant scalar theory by introducing a conformal gauge field. We comment on the extrapolation of this idea to the fermionic field and study the trace anomaly for the scalar case by using the path integral formalism.

  17. Tracing colonial and postcolonial recordkeeping in Zimbabwe ...

    African Journals Online (AJOL)

    The article traces archival development in Zimbabwe from the colonial to the postcolonial periods. Like in many African colonies, the foundations for formal recordkeeping in Zimbabwe were laid during colonial administration and this article argues that there is a direct relationship between what is happening today and the ...

  18. A SIMPLE SPECTROPHOTOMETRIC DETERMINATION OF TRACE ...

    African Journals Online (AJOL)

    A simple and sensitive spectrophotometric method has been developed for the determination of trace amounts of vanadium using thionin as a chromogenic reagent. The proposed method is based on the reaction of vanadium(V) with potassium iodide in acid medium to liberate iodine, which bleaches the violet colour of ...

  19. Urban environmental geochemistry of trace metals

    International Nuclear Information System (INIS)

    Wong, Coby S.C.; Li Xiangdong; Thornton, Iain

    2006-01-01

    As the world's urban population continues to grow, it becomes increasingly imperative to understand the dynamic interactions between human activities and the urban environment. The development of urban environmental geochemistry has yielded a significant volume of scientific information about geochemical phenomena found uniquely in the urban environment, such as the distribution, dispersion, and geochemical characteristics of some toxic and potentially toxic trace metals. The aim of this paper is to provide an overview of the development of urban environmental geochemistry as a field of scientific study and highlight major transitions during the course of its development from its establishment to the major scientific interests in the field today. An extensive literature review is also conducted of trace metal contamination of the urban terrestrial environment, in particular of urban soils, in which the uniqueness of the urban environment and its influences on trace metal contamination are elaborated. Potential areas of future development in urban environmental geochemistry are identified and discussed. - Urban environmental geochemistry as a scientific discipline provides valuable information on trace metal contamination of the urban environment and its associated health effects

  20. Papa, a Particle Tracing Code in Pascal

    NARCIS (Netherlands)

    Haselhoff, E.H.; Haselhoff, Eltjo H.; Ernst, G.J.

    1990-01-01

    During the design of a 10 ¿m high-gain FEL oscillator (TEUFEL Project) we developed a new particle-tracing code to perform simulations of thermionic- and photo-cathode electron injectors/accelerators. The program allows predictions of current, energy and beam emittance in a user-specified linac

  1. Plasma trace metals during total parenteral alimentation.

    Science.gov (United States)

    Solomons, N W; Layden, T J; Rosenberg, I H; Vo-Khactu, K; Sandstead, H H

    1976-06-01

    The plasma concentrations of the trace metals zinc and copper were studied prospectively in 13 patients with gastrointestinal diseases treated with parenteral alimentation (TPA) for periods of from 8 days to 7 1/2 weeks. Plasma copper levels fell rapidly and consistently in all patients, with an overall rate of - 11 mug per 100 ml per week. Zinc concentrations declined in 10 of 13 patients at a more gradual rate. Analysis of the standard parenteral alimentation fluids revealed zinc content equivalent to 50% of the daily requirement and a negligible content of copper. From combined analysis of plasma zinc, hair zinc, and taste acuity, there is evidence that increased utilization or redistribution within the body may effect plasma concentrations in some patients. Neither an increase in urinary excretion nor a primary decrease in plasma binding proteins appeared to be a major factor in lowering plasma trace metal concentrations. These findings indicate that a marked decrease in plasma copper is regular and a decline in plasma zinc is common during TPA using fluids unsupplemented with trace metals. Supplementation of parenteral alimentation fluids with the trace metals zinc and copper is recommended.

  2. Trace elements in glucometabolic disorders: an update

    Directory of Open Access Journals (Sweden)

    Wiernsperger Nicolas

    2010-12-01

    Full Text Available Abstract Many trace elements, among which metals, are indispensable for proper functioning of a myriad of biochemical reactions, more particularly as enzyme cofactors. This is particularly true for the vast set of processes involved in regulation of glucose homeostasis, being it in glucose metabolism itself or in hormonal control, especially insulin. The role and importance of trace elements such as chromium, zinc, selenium, lithium and vanadium are much less evident and subjected to chronic debate. This review updates our actual knowledge concerning these five trace elements. A careful survey of the literature shows that while theoretical postulates from some key roles of these elements had led to real hopes for therapy of insulin resistance and diabetes, the limited experience based on available data indicates that beneficial effects and use of most of them are subjected to caution, given the narrow window between safe and unsafe doses. Clear therapeutic benefit in these pathologies is presently doubtful but some data indicate that these metals may have a clinical interest in patients presenting deficiencies in individual metal levels. The same holds true for an association of some trace elements such as chromium or zinc with oral antidiabetics. However, this area is essentially unexplored in adequate clinical trials, which are worth being performed.

  3. Tracing And Control Of Engineering Requirements

    Science.gov (United States)

    Turner, Philip R.; Stoller, Richard L.; Neville, Ted; Boyle, Karen A.

    1991-01-01

    TRACER (Tracing and Control of Engineering Requirements) is data-base/word-processing software system created to document and maintain order of both requirements and descriptions associated with engineering project. Implemented on IBM PC under PC-DOS. Written with CLIPPER.

  4. Changes in Trace Elements In Kwashiorkor

    African Journals Online (AJOL)

    1974-03-13

    Mar 13, 1974 ... Evidence exists that trace elements are in imbalance in kwashiorkor. A decrease in the plasma zinc and copper'· and liver copper'l has been found. The copper content of hair determined in kwashiorkor patients gave contro- versial results.""" Elood selenium levels decreased, and the in vivo red cell uptake ...

  5. Trace Metals Bioaccumulation Potentials of Three Indigenous ...

    African Journals Online (AJOL)

    The rapid increase in the number of industries may have increased the levels of trace metals in the soil. Phytoremediation of these polluted soils using indigenous grasses is now considered an alternative method in remediating these polluted soils. The present study investigated and compared the ability of three ...

  6. Environmental Risk Limits for Nine Trace Elements

    NARCIS (Netherlands)

    Vlaardingen PLA van; Posthumus R; Posthuma-Doodeman CJAM; SEC

    2005-01-01

    In this report, we present an update of environmental risk limits (ERLs), based on the literature, for nine trace elements, namely, beryllium (Be), vanadium (V), cobalt (Co), selenium (Se), molybdenum (Mo), tin (Sn), antimony (Sb), barium (Ba) and thallium (Tl). The updated ERLs, established for

  7. Backward ray tracing for ultrasonic imaging

    NARCIS (Netherlands)

    Breeuwer, R.

    1990-01-01

    Focused ultrasonic beams frequently pass one or more media interfaces, strongly affecting the ultrasonic beamshape and focusing. A computer program, based on backward ray tracing was developed to compute the shape of a corrected focusing mirror. This shape is verified with another program; then the

  8. A half century of experimental neuroanatomical tracing.

    Science.gov (United States)

    Lanciego, José L; Wouterlood, Floris G

    2011-11-01

    Most of our current understanding of brain function and dysfunction has its firm base in what is so elegantly called the 'anatomical substrate', i.e. the anatomical, histological, and histochemical domains within the large knowledge envelope called 'neuroscience' that further includes physiological, pharmacological, neurochemical, behavioral, genetical and clinical domains. This review focuses mainly on the anatomical domain in neuroscience. To a large degree neuroanatomical tract-tracing methods have paved the way in this domain. Over the past few decades, a great number of neuroanatomical tracers have been added to the technical arsenal to fulfill almost any experimental demand. Despite this sophisticated arsenal, the decision which tracer is best suited for a given tracing experiment still represents a difficult choice. Although this review is obviously not intended to provide the last word in the tract-tracing field, we provide a survey of the available tracing methods including some of their roots. We further summarize our experience with neuroanatomical tracers, in an attempt to provide the novice user with some advice to help this person to select the most appropriate criteria to choose a tracer that best applies to a given experimental design. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Atmospheric trace metal concentrations in Suspended Particulate ...

    African Journals Online (AJOL)

    The correlation matrix analysis showed a strong positive correlation between the kitchen, living room and outdoor sites, suggesting identical sources of the trace metals. Principal component analysis (PCA) identified two fundamental sources of the metals, whichwas further confirmed by the hierarchical cluster analysis.

  10. Ray tracing in anisotropic media with singularities

    Czech Academy of Sciences Publication Activity Database

    Vavryčuk, Václav

    2001-01-01

    Roč. 145, č. 1 (2001), s. 265-276 ISSN 0956-540X R&D Projects: GA ČR GA205/00/1350 Institutional research plan: CEZ:AV0Z3012916 Keywords : anisotropic media * ray tracing * singularities Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.366, year: 2001

  11. Trace Metals Bioaccumulation Potentials of Three Indigenous ...

    African Journals Online (AJOL)

    User

    Abstract. The rapid increase in the number of industries may have increased the levels of trace metals in the soil. Phytoremediation of these polluted soils using indigenous grasses is now considered an alternative method in remediating these polluted soils. The present study investigated and compared the ability of three ...

  12. Tracing pathogens in the food chain

    NARCIS (Netherlands)

    Brul, S.; Fratamico, P.M.; McMeekin, T.A.

    2010-01-01

    Successful methods for the detection and investigation of outbreaks of foodborne disease are essential for ensuring consumer safety. Increased understanding of the transmission of pathogens in food chains will also assist efforts to safeguard public health. Tracing pathogens in the food chain

  13. Software for computerised analysis of cardiotocographic traces.

    Science.gov (United States)

    Romano, M; Bifulco, P; Ruffo, M; Improta, G; Clemente, F; Cesarelli, M

    2016-02-01

    Despite the widespread use of cardiotocography in foetal monitoring, the evaluation of foetal status suffers from a considerable inter and intra-observer variability. In order to overcome the main limitations of visual cardiotocographic assessment, computerised methods to analyse cardiotocographic recordings have been recently developed. In this study, a new software for automated analysis of foetal heart rate is presented. It allows an automatic procedure for measuring the most relevant parameters derivable from cardiotocographic traces. Simulated and real cardiotocographic traces were analysed to test software reliability. In artificial traces, we simulated a set number of events (accelerations, decelerations and contractions) to be recognised. In the case of real signals, instead, results of the computerised analysis were compared with the visual assessment performed by 18 expert clinicians and three performance indexes were computed to gain information about performances of the proposed software. The software showed preliminary performance we judged satisfactory in that the results matched completely the requirements, as proved by tests on artificial signals in which all simulated events were detected from the software. Performance indexes computed in comparison with obstetricians' evaluations are, on the contrary, not so satisfactory; in fact they led to obtain the following values of the statistical parameters: sensitivity equal to 93%, positive predictive value equal to 82% and accuracy equal to 77%. Very probably this arises from the high variability of trace annotation carried out by clinicians. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Trace elements in wine and other beverages

    International Nuclear Information System (INIS)

    Eschnauer, H.

    1974-01-01

    Survey of the mostly physical methods of analysis (e.g. activation analysis) for the dectection of trace elements in wine and in other alcoholic and non-alcoholic beverages as well as for detection of radioactivity (natural and man-made) in these beverages. (HP) [de

  15. Assessment of trace metal levels in size-resolved particulate matter in the area of Leipzig

    Science.gov (United States)

    Fomba, Khanneh Wadinga; van Pinxteren, Dominik; Müller, Konrad; Spindler, Gerald; Herrmann, Hartmut

    2018-03-01

    Size-resolved trace metal concentrations at four sites in Leipzig (Germany) and its surrounding were assessed between the winter of 2013 and the summer of 2015. The measurements were performed in parallel at; traffic dominated (Leipzig - Mitte, LMI), traffic and residential dominated (Eisenbahnstrasse, EIB), urban background (TROPOS, TRO) and regional background (Melpitz, MEL) sites. In total, 19 trace metals, i.e. K, Ca, Ti, Mn, Fe, Cu, Zn, As, Se, Ba, V, Pb, Ni, Cr, Sr, Sn, Sb, Co and Rb were analysed using total reflection x-ray fluorescence (TXRF). The major metals were Fe, K and Ca with concentrations ranging between; 31-440 ng/m3, 42-153 ng/m3 and 24-322 ng/m3, respectively, while the trace metals with the lowest concentrations were Co, Rb and Se with concentrations of; fine mode. Trace metal sources were related to crustal matter and road dust re-suspension for metals such as Ca, Fe, Co, Sr, and Ti, brake and tire wear (Cu, Sb, Ba, Fe, Zn, Pb), biomass burning (K, Rb), oil and coal combustion (V, Zn, As, Pb). Crustal matter contributed 5-12% in winter and 8-19% in summer of the PM10 mass. Using Cu and Zn as markers for brake and tire wear, respectively, the estimated brake and tire wear contributions to the PM10 mass were 0.1-0.8% and 1.7-2.9%, respectively. The higher contributions were observed at the traffic sites while the lower contributions were observed at the regional background site. In total, non-exhaust emissions could account for about 10-22% of the PM10 mass in the summer and about 7-15% of the PM10 mass in the winter.

  16. Green's functions and trace formulas for generalized Sturm-Liouville problems related by Darboux transformations

    International Nuclear Information System (INIS)

    Schulze-Halberg, Axel

    2010-01-01

    We study Green's functions of the generalized Sturm-Liouville problems that are related to each other by Darboux -equivalently, supersymmetrical - transformations. We establish an explicit relation between the corresponding Green's functions and derive a simple formula for their trace. The class of equations considered here includes the conventional Schroedinger equation and generalizations, such as for position-dependent mass and with linearly energy-dependent potential, as well as the stationary Fokker-Planck equation.

  17. Tracing the first stars and galaxies of the Milky Way

    Science.gov (United States)

    Griffen, Brendan F.; Dooley, Gregory A.; Ji, Alexander P.; O'Shea, Brian W.; Gómez, Facundo A.; Frebel, Anna

    2018-02-01

    We use 30 high-resolution dark matter haloes of the Caterpillar simulation suite to probe the first stars and galaxies of Milky Way-mass systems. We quantify the environment of the high-z progenitors of the Milky Way and connect them to the properties of the host and satellites today. We identify the formation sites of the first generation of Population III (Pop III) stars (z ˜ 25) and first galaxies (z ˜ 22) with several different models based on a minimum halo mass. This includes a simple model for radiative feedback, the primary limitation of the model. Through this method we find approximately 23 000 ± 5000 Pop III potentially star-forming sites per Milky Way-mass host, though this number is drastically reduced to ˜550 star-forming sites if feedback is included. The majority of these haloes identified form in isolation (96 per cent at z = 15) and are not subject to external enrichment by neighbouring haloes (median separation ˜1 kpc at z = 15), though half merge with a system larger than themselves within 1.5 Gyr. Using particle tagging, we additionally trace the Pop III remnant population to z = 0 and find an order of magnitude scatter in their number density at small (i.e. r 50 kpc) galactocentric radii. We provide fitting functions for determining the number of progenitor minihalo and atomic cooling halo systems that present-day satellite galaxies might have accreted since their formation. We determine that observed dwarf galaxies with stellar masses below 104.6 M⊙ are unlikely to have merged with any other star-forming systems.

  18. Critical review of conservation equations for two-phase flow in the U.S. NRC TRACE code

    International Nuclear Information System (INIS)

    Wulff, Wolfgang

    2011-01-01

    Research highlights: → Field equations as implemented in TRACE are incorrect. → Boundary conditions needed for cooling of nuclear fuel elements are wrong. → The two-fluid model in TRACE is not closed. → Three-dimensional flow modeling in TRACE has no basis. - Abstract: The field equations for two-phase flow in the computer code TRAC/RELAP Advanced Computational Engine or TRACE are examined to determine their validity, their capabilities and limitations in resolving nuclear reactor safety issues. TRACE was developed for the NRC to predict thermohydraulic phenomena in nuclear power plants during operational transients and postulated accidents. TRACE is based on the rigorously derived and well-established two-fluid field equations for 1-D and 3-D two-phase flow. It is shown that: (1)The two-fluid field equations for mass conservation as implemented in TRACE are wrong because local mass balances in TRACE are in conflict with mass conservation for the whole reactor system, as shown in Section . (2)Wrong equations of motion are used in TRACE in place of momentum balances, compromising at branch points the prediction of momentum transfer between, and the coupling of, loops in hydraulic networks by impedance (form loss and wall shear) and by inertia and thereby the simulation of reactor component interactions. (3)Most seriously, TRACE calculation of heat transfer from fuel elements is incorrect for single and two-phase flows, because Eq. of the TRACE Manual is wrong (see Section ). (4)Boundary conditions for momentum and energy balances in TRACE are restricted to flow regimes with single-phase wall contact because TRACE lacks constitutive relations for solid-fluid exchange of momentum and heat in prevailing flow regimes. Without a quantified assessment of consequences from (3) to (4), predictions of phasic fluid velocities, fuel temperatures and important safety parameters, e.g., peak clad temperature, are questionable. Moreover, TRACE cannot predict 3-D single- or

  19. Determination of trace elements in sedimentary phosphorites with ultraviolet laser ablation ICP-MS

    International Nuclear Information System (INIS)

    Walsh, S.R.

    1999-01-01

    Full text: Analyses of trace elements in sedimentary phosphorites used in fertiliser production are important because many trace elements that are enriched in these rocks can be further enriched during fertiliser production and then transferred to plants and animals. Few detailed studies of trace metals in potential phosphate ores have been published and most published studies involve few samples or present data for a limited range of trace elements. This study uses UV laser ablation ICP-MS with 3mm line burns and calibration against NIST glass standards to provide rapid multi-element analyses of an extensive phosphorite specimen collection from around the world. Because there are no published reports using UV laser ablation to examine phosphorites, no limitations were placed on element combinations during initial multi-element analyses. Selection of up to 30 elements produced unreliable results for a single nodular phosphorite sample compared to data from several other analytical techniques. Results from PIXE analyses were then used for cross-calibration of several major and trace elements determined using UV laser ablation and it was found that three groups of elements need to be analysed separately. Although elements, whether as major or trace elements, within any one group can be determined in any number or combination, elements from other groups cannot be reliably determined at the same time. Group 1 includes any element not in Period 4 of the Periodic Table, the other two groups consist of particular elements from Period 4. Membership of groups is probably related to one or more of the following: 1) saturation of various mass numbers in Period 4 that coincide with argon isotopes, 2) interference from argyles and doubly charged ions that form during analysis from phosphorus, calcium and other light elements in the phosphorites, and 3) the effect of the high energy/frequency UV laser. Raw data are adjusted using results from analytical techniques such as PIXE

  20. It’s all about mechanisms - what process-tracing case studies should be tracing

    DEFF Research Database (Denmark)

    Beach, Derek

    2016-01-01

    It is widely agreed that the core of Process-tracing (PT) as a distinct case study methodology is that it involves tracing causal mechanisms that link causes (X) with their effects (i.e. outcomes) (Y). Yet when we look at the methodological literature on PT, there is considerable ambiguity and di...... linking X and Y into a series of interlocking parties composed of entities engaging in activities that transmit causal forces from cause to outcome.......It is widely agreed that the core of Process-tracing (PT) as a distinct case study methodology is that it involves tracing causal mechanisms that link causes (X) with their effects (i.e. outcomes) (Y). Yet when we look at the methodological literature on PT, there is considerable ambiguity...

  1. Application of trace element analysis to determine trace element concentrations in the field of medicine

    International Nuclear Information System (INIS)

    Kasperek, K.; Feinendegen, L.E.

    1976-01-01

    Applied trace elements research in medicine requires a sensitive and efficient technique of trace elements analysis such as, e.g., neutron activation analysis. Essential trace elements act as stabilisators (iron in haem), structural elements (silicium in fibrous tissue), in hormones (iodine in thyroid hormone), in vitamins (cobalt in vitamin B 12), and in enzymes. Most of the essential trace elements act as coenzymes or in coenzymes or directly as metabolic catalysators. For example, selenium deficiency in PKU and maple syrup patients receiving dietary treatment can be detected by determining the selenium content of the serum, while low selenium values in the whole blood indicate liver cirrhosis. Acrodermatitis enteropathica can be diagnosed by determinig zinc in the serum, and pancreatic insufficiency by determining zinc in the pancreatic juice. Zinc also plays a part in disturbances of growth, in the healing of wounds, and in the insulin metabolism. Cobalt is important in some types of anaemia and in myocardiopathies. Trace elements are also necessary in the treatment of diseases, e.g. iron cobalt in some types of anaemia, and zinc in the delayed healing of wounds in the postoperative phase and in acrodermatitis enteropathica. Chromium is now being tested for the treatment of diabetes mellitus, and fluorides may be of interest in the treatment of osteoporosis. Finally, trace elements are important in the aetiology of acute poisoning, in nutrition, and in environmental protection. (orig./AK) [de

  2. Vaporization of trace element species from coal under gasification and combustion conditions: Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1989-03-01

    The objective of this project was to establish the chemical forms and relative abundance of trace inorganic vapor species in coal during combustion and gasification. A joint experimental and calculational program to observe the vaporization of Illinois No. 6 bituminous and Wyodak subbituminous was performed. Experimental studies were performed by Knudsen cell mass spectroscopy on samples of each coal that were ashed at low temperature by an oxygen plasma. To simulate actual coal more closely, some samples were only partially ashed to retain more of the original organic components. Vapor species were identified and their abundances measured over the temperature range 300-1700 K. In the first year of the program, vaporization from the coal ash alone was studied. Dynamic partial pressures were measured against temperature and time. Vapor species of 32 major or trace elements were identified. During the second year of the program, mass spectrometry experiments addressed the effects of added gases (O/sub 2/, CO/sub 2/, and H/sub 2/O) on the identities and abundances of trace element vapor species. Coincident with experimental studies, trace element vaporization behavior was evaluated by Gibbs energy minimization calculations. A data base including both solution and pure condensed and gaseous components was compiled. The behavior of Wyodak coal at 1 atm total pressure was evaluated over the temperature range 300--1800 K and the oxygen partial pressure range from 10/sup /minus/1/ to 10/sup /minus/25/ atm. Results were used to evaluate the effects on trace element volatility of several proposed strategies for containment removal. 13 refs., 23 figs., 23 tabs.

  3. Mass spectrometry a versatile aid to inorganic analysis

    International Nuclear Information System (INIS)

    Stefani, Rene

    1976-01-01

    Several hundred publications have appeared in the last three years that deal with applications of Mass Spectrometry to inorganic analysis. Bulk and localized trace analysis, surface and thin film characterization and microstructure examination are currently performed by Secondary Ion Mass Spectrometry, Spark Source Mass Spectrometry and the newly developed Laser Probe Mass Spectrometry. Suitable experimental procedures allow insulators, biologic materials and microsamples to be analysed. In spite of the classification by techniques this review is essentially devoted to the most significant papers in analytical applications but instrumental and basic features are sometimes introduced to support the discussions

  4. Techniques for information extraction from compressed GPS traces : final report.

    Science.gov (United States)

    2015-12-31

    Developing techniques for extracting information requires a good understanding of methods used to compress the traces. Many techniques for compressing trace data : consisting of position (i.e., latitude/longitude) and time values have been developed....

  5. The Effect of Dietary Inorganic and Organic Trace Mineral ...

    African Journals Online (AJOL)

    82kg were assigned to five dietary treatments to investigate the effect of dietary inorganic and organic trace mineral supplementation on growth performance; fecal mineral excretion and apparent digestibility. Trace minerals considered were ...

  6. Life Support Systems: Trace Contaminant and Particulate Control

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Exploration Systems (AES) Life Support Systems project Trace Contaminant and Particulate Control task: Work in the area of trace contamination and...

  7. Some problems associated with trace contaminant removal systems for spacecabins

    Science.gov (United States)

    Wydeven, T.

    1985-01-01

    Potential problems associated with acid gas sorbents, activated charcoal beds and the catalytic oxidizer proposed for spacecabin trace contaminant control are discussed. The need for further research on atmospheric trace contaminant control methods is noted.

  8. Ben Macdhui High Altitude Trace Gas and Aerosol Transport Experiment

    CSIR Research Space (South Africa)

    Piketh, SJ

    1999-01-01

    Full Text Available The Ben Macdhui High Altitude Aerosol and Trace Gas Transport Experiment (BHATTEX) was started to characterize the nature and magnitude of atmospheric, aerosol and trace gas transport paths recirculation over and exiting from southern Africa...

  9. The determination of trace elements in uranium ores by x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    De Villiers, W. van Z.

    1983-11-01

    The determination of 17 trace elements (As, Ba, Co, Cr, Cu, Mo, Nb, Ni, Pb, Rb, Sr, Th, U, V, Y, Zn and Zr) in uranium ores by x-ray fluorescence spectrometry was investigated in this study. The determination of major elements was also necessary for the calculation of mass absorption coefficients. Initially a method was developed for the determination of the elements of interest in unmineralised silicates. Correction for absorption of radiation by the sample were made by means of mass absorption coefficients which were obtained from the relation between the inverse of the mass absorption coefficient and the intensity of the Compton scattering peak. The Feather and Willis method was used for determining the background intensity at the peak positions as well as for mass absorption coefficients. It was observed that the background intensity in the region of the uranium lines increases with increasing uranium content of the sample

  10. Trace Minerals and Livestock: Not Too Much Not Too Little

    OpenAIRE

    L?pez-Alonso, Marta

    2012-01-01

    The new approaches of the animal production systems make managing the mineral nutrition a challenge. Versus the excessive, trace mineral supply in intensively managed livestock, well above the physiological requirements, is the no trace mineral supplementation of organic systems, which become highly dependent on trace minerals in the soil. Nowadays, in addition to the animal health perspective, trace mineral nutrition must be environment friendly and allow getting mineral-enriched animal prod...

  11. NSF-RANN Trace Contaminants Program directory

    International Nuclear Information System (INIS)

    Purnell, P.A.; Smith, S.K.; Wilkes, C.F.

    1976-10-01

    This directory is designed to aid effective communication throughout the National Science Foundation's Trace Contaminants Program, Research Applied to National Needs. The majority of the participants in the Program are represented by name, address, telephone number, and a very brief description of research interest. The directory has five major divisions to facilitate its use. Section I contains a listing of the program managers associated with the NSF-RANN Trace Contaminants Program. Section II lists the principal investigators, co-principal investigators, and coordinators of each of the research grants in the Program. Section III lists the personnel by individual projects. Section IV contains a total alphabetic listing complete with project titles and Section V contains a keyword index. This directory is maintained by the Toxic Materials Information Center as part of the Environmental Resource Center of the Information Center Complex, Information Division, Oak Ridge National Laboratory

  12. Trace minerals in human growth and development.

    Science.gov (United States)

    Castillo-Durán, C; Cassorla, F

    1999-01-01

    Trace mineral deficiencies may affect several biological functions in humans, including physical growth, psychomotor development and immunity. We have reviewed the mechanisms whereby several trace mineral deficiencies may affect these biological functions at different ages (fetal life, infancy, childhood and adolescence), as well as the evidence supporting this association. We describe the effects of zinc deficiency on the hormonal regulation of growth and sexual development in both humans and animal models. We provide data regarding the effects of iron deficiency on growth and psychomotor development. We mention the effects of copper, manganese, selenium and iodine deficiencies on growth and development. We conclude that iron deficiency may affect psychomotor development, but does not appear to affect growth. Zinc deficiency may cause growth retardation and psychomotor delay.

  13. Trace metal fronts in European shelf waters

    International Nuclear Information System (INIS)

    Kremling, K.

    1983-01-01

    The Hebrides shelf edge area is characterized by strong horizontal salinity gradients (fronts) which mark the boundary between Scottish coastal and oceanic waters. The results presented here, obtained in summer 1981 on a transect between the open north Atlantic and the German Bight, confirm that the hydrographical front is accompanied by dramatic increases in inorganic nutrients (phosphate, silicate) and dissolved trace elements such as Cd, Cu, Mn, and 226 Ra. These data (together with measurements from North Sea regions) suggest that the trace metals are mobilized from partly reduced (organic-rich) sediments and vertically mixed into the surface waters. The regional variations evident from the transect are interpreted as being the result of the hydrography prevailing in waters around the British Isles. (author)

  14. Quantifying Bell nonlocality with the trace distance

    Science.gov (United States)

    Brito, S. G. A.; Amaral, B.; Chaves, R.

    2018-02-01

    Measurements performed on distant parts of an entangled quantum state can generate correlations incompatible with classical theories respecting the assumption of local causality. This is the phenomenon known as quantum nonlocality that, apart from its fundamental role, can also be put to practical use in applications such as cryptography and distributed computing. Clearly, developing ways of quantifying nonlocality is an important primitive in this scenario. Here, we propose to quantify the nonlocality of a given probability distribution via its trace distance to the set of classical correlations. We show that this measure is a monotone under the free operations of a resource theory and, furthermore, that it can be computed efficiently with a linear program. We put our framework to use in a variety of relevant Bell scenarios also comparing the trace distance to other standard measures in the literature.

  15. Hierarchical Traces for Reduced NSM Memory Requirements

    Science.gov (United States)

    Dahl, Torbjørn S.

    This paper presents work on using hierarchical long term memory to reduce the memory requirements of nearest sequence memory (NSM) learning, a previously published, instance-based reinforcement learning algorithm. A hierarchical memory representation reduces the memory requirements by allowing traces to share common sub-sequences. We present moderated mechanisms for estimating discounted future rewards and for dealing with hidden state using hierarchical memory. We also present an experimental analysis of how the sub-sequence length affects the memory compression achieved and show that the reduced memory requirements do not effect the speed of learning. Finally, we analyse and discuss the persistence of the sub-sequences independent of specific trace instances.

  16. Examination of paints by trace element analysis.

    Science.gov (United States)

    Krishnan, S S

    1976-10-01

    Trace element analysis using neutron activation analysis is effective and valuable, particularly in the examination of white household paint. Although physical appearance and resin composition are generally similar in these paint samples, trace element composition provides an effective way of distinguishing among them. In the case of automobile paint samples, NAA serves as an important additional technique for discrimination. The technique is important when sample sizes are very small. The technique developed takes a few minutes for sample preparation, a few hours of irradiation time (during which the examiner's presence is not required), and then a few minutes for counting and obtaining quantitative multielement concentration patterns. A technician can easily handle 30 to 50 samples per day.

  17. Trace element distribution in geological crystals

    Energy Technology Data Exchange (ETDEWEB)

    Den Besten, J.L.; Jamieson, D.N.; Weiser, P.S. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Channelling is a useful microprobe technique for determining the structure of crystals, but until now has not been performed on geological crystals. The composition has been investigated rather than the structure, which can further explain the origin of the crystal and provide useful information on the substitutionality of trace elements. This may then lead to applications of extraction of valuable metals and semiconductor electronics. Natural crystals of pyrite, FeS{sub 2}, which contains a substantial concentration of gold were channeled and examined to identify the channel axis orientation. Rutherford Backscattering (RBS) and Particle Induced X-Ray Emission (PIXE) spectra using MeV ions were obtained in the experiment to provide a comparison of lattice and non-lattice trace elements. 3 figs.

  18. Assessment of trace element stabilization in soil

    OpenAIRE

    Kumpiene, Jurate

    2005-01-01

    The thesis deals with the remediation of trace element contaminated soil by the chemical stabilization technique. The objective is to complement the knowledge about possibilities of applying the stabilization either (1) as an alternate soil remediation method to excavation and landfilling or (2) for a pre-treatment of contaminated soil before landfilling. The work is based on two case studies of the stabilization of 1) Cr, Cu, As, and Zn contaminated soil using metallic iron and 2) Pb and Cu ...

  19. Cytocompatible cellulose hydrogels containing trace lignin

    Energy Technology Data Exchange (ETDEWEB)

    Nakasone, Kazuki; Kobayashi, Takaomi, E-mail: takaomi@nagaoakut.ac.jp

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm{sup 2} and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  20. TRACE ELEMENTS IN FRUIT AND VEGETABLE

    OpenAIRE

    Stefania Papa; Laura Cerullo; Anna Di Monaco; Giovanni Bartoli; Antonietta Fioretto

    2009-01-01

    The concentration of six different trace metals [vanadium (V), nickel (Ni), chromium (Cr),  lead (Pb), copper (Cu) and cadmium (Cd)] were determined in various fruit and vegetables [peach (Prunus persica L.), plum (Prunus domestica L.), tomato (Solanum lycopersicum L.), courgette or marrow (Cucurbita pepo L.) and lettuce (Lactuca sativa L.)] provided by diverse farms. Metal distribution was also separately evaluated, in skin and pulp, where it was possible. Their contributions to human daily ...

  1. The Combinatorial Trace Method in Action

    Science.gov (United States)

    Krebs, Mike; Martinez, Natalie C.

    2013-01-01

    On any finite graph, the number of closed walks of length k is equal to the sum of the kth powers of the eigenvalues of any adjacency matrix. This simple observation is the basis for the combinatorial trace method, wherein we attempt to count (or bound) the number of closed walks of a given length so as to obtain information about the graph's…

  2. Trace elements and protein in human milk

    International Nuclear Information System (INIS)

    Abusamra, Y.I.H.

    1995-01-01

    The trace elements Zn, Fe, Cu, Mn, Ni and Pb and some related major elements which are Ca, Cl K and total protein contents of human samples from ninety mothers were examined in this study. Samples were collected from Khartoum, Khartoum North and Omdurman, from the second day of delivery up to the third month where the milk reaches a relatively stable levels. These samples representing different stages of lactation which are colostrum ( 1-3 days ), tranitional ( up to 14 days ) and mature milk. The principle aim of this study is to measure the trace elements and protein contents in relation to stage of lactation and to compare with the literature. Atomic absorption spectroscopy and X-ray fluorescence were used to measure trace elements in the samples. The methods were found to be quite reliable as proved by the analysis of the standard reference material HM-1. Whereas neutron activation analysis was used for measurements of total protein. Colostrum was found to have the highest amounts of trace elements and protein. Fe mean concentration was 273 g/dm 3 at colostrum stage and it decreased to 146 g/dm 3 in mature milk ( 49% ). Zn decreased from 6000 g/dm 3 in colostrum to 1300 g/dm 3 in mature stage ( 78% ). Mn was 12g/dm 3 in colostrum, and it decreased to 2.9 g/dm 3 in mature milk ( 75% ). Cu decreased from 370 g/dm 3 to 117 g/dm 3 ( 68% ). Ni decreased from 24 g/dm 3 to 8.8 g/dm 3 ( 63% ) and Pb from 12 g/dm 3 to 2.6 g/dm 3 ( 76% ). Total protein was 37.3% of the dry milk in colostrum and it was 12.2% in mature milk. (author). 75 refs., 25 tabs., 30 figs

  3. Trace-element analysis in environmental sciences

    International Nuclear Information System (INIS)

    Valkovic, V.; Moschini, G.

    1988-01-01

    The use of charged-particle accelerators in trace-element analysis in the field of environmental sciences is described in this article. Nuclear reactions, charged-particle-induced X-ray emission as well as other nuclear and atomic processes can be used individually, or combined, in developing adequate analytical systems. In addition to concentration levels, concentration levels, concentration profiles can be measured, resulting in unique information. Some examples of experiments performed are described together with the suggestions for future measurements [pt

  4. Perturbative Semiclassical Trace Formulae for Harmonic Oscillators

    DEFF Research Database (Denmark)

    Møller-Andersen, Jakob; Ögren, Magnus

    2015-01-01

    U(D) to O(D) symmetry breaking. We derive the gross structure of the semiclassical spectrum from periodic orbit theory, in the form of a perturbative (ħ → 0) trace formula. We then show how to apply the results to even-order polynomial potentials, possibly including mean-field terms. We have drawn...... the conclusion that the gross structure of the quantum spectrum is determined from only classical circular and diameter orbits for this class of systems....

  5. On Newton-Cartan trace anomalies

    International Nuclear Information System (INIS)

    Auzzi, Roberto; Baiguera, Stefano; Nardelli, Giuseppe

    2016-01-01

    We classify the trace anomaly for parity-invariant non-relativistic Schrödinger theories in 2+1 dimensions coupled to background Newton-Cartan gravity. The general anomaly structure looks very different from the one in the z=2 Lifshitz theories. The type A content of the anomaly is remarkably identical to that of the relativistic 3+1 dimensional case, suggesting the conjecture that an a-theorem should exist also in the Newton-Cartan context.

  6. Inorganic and organic trace mineral supplementation in weanling pig diets

    Directory of Open Access Journals (Sweden)

    MARIA C. THOMAZ

    2015-06-01

    Full Text Available A study was conducted to evaluate the effects of dietary inorganic and organic trace minerals in two levels of supplementation regarding performance, diarrhea occurrence, hematological parameters, fecal mineral excretion and mineral retention in metacarpals and liver of weanling pigs. Seventy piglets weaned at 21 days of age with an average initial body weight of 6.70 ± 0.38 kg were allotted in five treatments: control diet (no added trace mineral premix; 50% ITMP (control diet with inorganic trace mineral premix supplying only 50% of trace mineral requirements; 50% OTMP (control diet with organic trace mineral premix supplying only 50% of trace mineral requirements; 100% ITMP (control diet with inorganic trace mineral premix supplying 100% of trace mineral requirements; and 100% OTMP (control diet with organic trace mineral premix supplying 100% of trace mineral requirements. Feed intake and daily weight gain were not affected by treatments, however, piglets supplemented by trace minerals presented better gain:feed ratio. No differences were observed at calcium, phosphorus, potassium, magnesium, sodium and sulfur excreted in feces per kilogram of feed intake. Treatments did not affect calcium, phosphorus, magnesium, sulfur and iron content in metacarpals. Trace mineral supplementation, regardless of level and source, improved the performance of piglets.

  7. The trace elements selenium, copper and zinc in pediatric practice

    NARCIS (Netherlands)

    M. van Caillie-Bertrand (Micheline)

    1985-01-01

    textabstractThe aim of the studies presented in this thesis was to investigate some pediatric aspects of trace element metabolism .The effects are described of 1) inadequate trace element intake , 2) trace element malabsorption mine and 4) sulphate.Within ,3) urinary losses during therapy with

  8. Trace element geochemistry of Amba Dongar carbonatite complex ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    melt partition coefficients for various trace elements, and the observed data from carbonatites, we have tried to simulate trace ... Keywords. Carbonatite; Amba Dongar; India; liquid immiscibility; trace elements; REE. Proc. Indian Acad. ...... clature, average chemical compositions and element dis- tribution; In: Carbonatites: ...

  9. More sum rules for quark and lepton masses

    International Nuclear Information System (INIS)

    Terazawa, Hidezumi.

    1990-04-01

    Sum rules for quark and lepton masses are derived from the Ward identity of Chanowitz and Ellis for the vertex function of the trace of the energy-momentum tensor and the two axial-vector currents and the partially conserved axial-vector current hypothesis. They indicate, among other things, that the constituent quark masses of u and d and those of the techniquarks, if any, are about 300 MeV and 300 GeV, respectively. (author)

  10. Accelerator mass spectrometry as a bioanalytical tool for nutritional research

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J.S.; Turteltaub, K.W.

    1997-09-01

    Accelerator Mass Spectrometry is a mass spectrometric method of detecting long-lived radioisotopes without regard to their decay products or half-life. The technique is normally applied to geochronology, but recently has been developed for bioanalytical tracing. AMS detects isotope concentrations to parts per quadrillion, quantifying labeled biochemicals to attomole levels in milligram- sized samples. Its advantages over non-isotopeic and stable isotope labeling methods are reviewed and examples of analytical integrity, sensitivity, specificity, and applicability are provided.

  11. FOREWORD: Special issue on mass

    Science.gov (United States)

    Gläser, Michael

    2003-12-01

    between weights and balances constitute the theme of the next article. After an introduction to the theoretical aspects of magnetic fields and magnetic forces, different measurement methods, international comparisons in this field, modelling the interacting forces and finally the impact on the new international recommendation for weights are presented. The moving-coil Watt balance and the superconducting magnetic levitation experiment are two of the experiments aimed at redefining the kilogram. 'Tracing Planck's constant to the kilogram by electromechanical methods' is the title of the corresponding article. It describes the principles of these experiments and reviews the efforts and results achieved at present in the laboratories concerned. Another approach to redefining the kilogram is reviewed in the article entitled 'Tracing the definition of the kilogram to the Avogadro constant using a silicon single crystal'. This approach is performed in a worldwide collaboration coordinated by the Working Group on the Avogadro Constant of the CIPM Consultative Committee for Mass and related quantities. An experiment for determining the atomic mass unit by ion accumulation follows a straightforward way for determining the mass of an atom by collecting ions, weighing and 'counting' them by measuring their total charge. This article reports on a 'third' way of redefining the kilogram. This approach is followed by only one laboratory and it is still at an early stage compared with the uncertainties already achieved by the other ones.

  12. The Role of Trace Elements in Tinnitus.

    Science.gov (United States)

    Yaşar, Mehmet; Şahin, Mehmet İlhan; Karakükçü, Çiğdem; Güneri, Erhan; Doğan, Murat; Sağıt, Mustafa

    2017-03-01

    In this study, we aimed to investigate the role of three trace elements, namely, zinc, copper, and lead, in tinnitus by analyzing the serum level of copper and lead and both the serum and tissue level of zinc. Eighty patients, who applied to outpatient otolaryngology clinic with the complaints of having tinnitus, and 28 healthy volunteers were included. High-frequency audiometry was performed, and participants who had hearing loss according to the pure tone average were excluded; tinnitus frequency and loudness were determined and tinnitus reaction questionnaire scores were obtained from the patients. Of all the participants, serum zinc, copper, and lead values were measured; moreover, zinc levels were examined in hair samples. The levels of trace elements were compared between tinnitus and control groups. The level of copper was found to be significantly lower in the tinnitus group (p = 0.02), but there was no significant difference between the groups in terms of the levels of zinc, neither in serum nor in hair, and lead in serum (p > 0.05). The lack of trace elements, especially that of "zinc," have been doubted for the etiopathogenesis of tinnitus in the literature; however, we only found copper levels to be low in patients having tinnitus.

  13. Photometric determination of traces of metals

    International Nuclear Information System (INIS)

    Onishi, H.

    1986-01-01

    The first three editions of this widely used classic were published under the title Colorimetric Determination of Traces of Metals, with E.B. Sandell as author. Part I (General Aspects) of the fourth edition was co-authored by E.B. Sandell and H. Onishi and published in 1978. After Sandell's death in 1984, Onishi assumed the monumental task of revising Part II. This book (Part IIA) consists of 21 chapters in which the photometric determinations of the individual metals, aluminium to lithium (including the lanthanoids), are described. Each chapter is divided into three sections: Separations, Methods of Determination, and Applications. The sections on Separations are of general interest and include methods based on precipitation, ion-exchange, chromatography, and liquid-liquid extraction. Molecular absorption and fluorescence techniques are described in the sections on determinations, and the emphasis is on the use of well-established reagents. Several reagents that have been recently introduced for the determination of trace levels of metals are also critically reviewed at the end of each section on methods of determination. Important applications of these methods to the determination of trace metals in complex organic and inorganic materials are described in detail at the end of each chapter

  14. The Relevant Physical Trace in Criminal Investigation

    Directory of Open Access Journals (Sweden)

    Durdica Hazard

    2016-01-01

    Full Text Available A criminal investigation requires the forensic scientist to search and to interpret vestiges of a criminal act that happened in the past. The forensic scientist is one of the many stakeholders who take part in the information quest within the criminal justice system. She reads the investigation scene in search of physical traces that should enable her to tell the story of the offense/crime that allegedly occurred. The challenge for any investigator is to detect and recognize relevant physical traces in order to provide clues for investigation and intelligence purposes, and that will constitute sound and relevant evidence for the court. This article shows how important it is to consider the relevancy of physical traces from the beginning of the investigation and what might influence the evaluation process. The exchange and management of information between the investigation stakeholders are important. Relevancy is a dimension that needs to be understood from the standpoints of law enforcement personnel and forensic scientists with the aim of strengthening investigation and ultimately the overall judicial process.

  15. Cross contamination in dual inlet isotope ratio mass spectrometers

    NARCIS (Netherlands)

    Meijer, H.A.J.; Neubert, R.E.M.; Visser, G.H.

    2000-01-01

    Since the early days of geochemical isotope ratio mass spectrometry there has always been the problem of cross contamination, i.e. the contamination of the sample gas with traces of reference gas land vice versa) in a dual inlet system and the analyzer itself. This was attributable to valve leakages

  16. Applications of accelerator mass spectrometry: advances and innovation

    International Nuclear Information System (INIS)

    Fifield, L.K.

    2004-01-01

    Emerging trends in the applications of accelerator mass spectrometry (AMS) are identified and illustrated with specific examples. Areas of application covered include rapid landscape evolution, calibration of the radiocarbon time scale, compound-specific radiocarbon studies, tracing of nuclear discharges, and searches for extraterrestrial isotopes

  17. The Mass Media and Political Socialization: Chile, 1970-2000

    Science.gov (United States)

    Walter, Amy R.

    2005-01-01

    This project seeks to determine the effect of the mass media on political attitudes and behaviors in Chile between the years 1970 and 2000. The relationship between the media and "political socialization" is just now gaining recognition in scholarly research, and Chile offers an excellent case study. This paper traces these two variables…

  18. Structural uncertainty in air mass factor calculation for NO

    NARCIS (Netherlands)

    Lorente Delgado, Alba; Folkert Boersma, K.; Yu, Huan; Dörner, Steffen; Hilboll, Andreas; Richter, Andreas; Liu, Mengyao; Lamsal, Lok N.; Barkley, Michael; Smedt, De Isabelle; Roozendael, Van Michel; Wang, Yang; Wagner, Thomas; Beirle, Steffen; Lin, Jin Tai; Krotkov, Nickolay; Stammes, Piet; Wang, Ping; Eskes, Henk J.; Krol, Maarten

    2017-01-01

    Air mass factor (AMF) calculation is the largest source of uncertainty in NO2 and HCHO satellite retrievals in situations with enhanced trace gas concentrations in the lower troposphere. Structural uncertainty arises when different retrieval methodologies are applied within the scientific community

  19. Trace Element Compositions and Defect Structures of High-Purity Quartz from the Southern Ural Region, Russia

    Directory of Open Access Journals (Sweden)

    Jens Götze

    2017-10-01

    Full Text Available Quartz samples of different origin from 10 localities in the Southern Ural region, Russia have been investigated to characterize their trace element compositions and defect structures. The analytical combination of cathodoluminescence (CL microscopy and spectroscopy, electron paramagnetic resonance (EPR spectroscopy, and trace-element analysis by inductively coupled plasma mass spectrometry (ICP-MS revealed that almost all investigated quartz samples showed very low concentrations of trace elements (cumulative concentrations of <50 ppm with <30 ppm Al and <10 ppm Ti and low abundances of paramagnetic defects, defining them economically as “high-purity” quartz (HPQ suitable for high-tech applications. EPR and CL data confirmed the low abundances of substitutional Ti and Fe, and showed Al to be the only significant trace element structurally bound in the investigated quartz samples. CL microscopy revealed a heterogeneous distribution of luminescence centres (i.e., luminescence active trace elements such as Al as well as features of deformation and recrystallization. It is suggested that healing of defects due to deformation-related recrystallization and reorganization processes of the quartz lattice during retrograde metamorphism resulted in low concentrations of CL activator and other trace elements or vacancies, and thus are the main driving processes for the formation of HPQ deposits in the investigated area.

  20. Coronal Mass Ejections: Observations

    Directory of Open Access Journals (Sweden)

    David F. Webb

    2012-06-01

    Full Text Available Solar eruptive phenomena embrace a variety of eruptions, including flares, solar energetic particles, and radio bursts. Since the vast majority of these are associated with the eruption, development, and evolution of coronal mass ejections (CMEs, we focus on CME observations in this review. CMEs are a key aspect of coronal and interplanetary dynamics. They inject large quantities of mass and magnetic flux into the heliosphere, causing major transient disturbances. CMEs can drive interplanetary shocks, a key source of solar energetic particles and are known to be the major contributor to severe space weather at the Earth. Studies over the past decade using the data sets from (among others the SOHO, TRACE, Wind, ACE, STEREO, and SDO spacecraft, along with ground-based instruments, have improved our knowledge of the origins and development of CMEs at the Sun and how they contribute to space weather at Earth. SOHO, launched in 1995, has provided us with almost continuous coverage of the solar corona over more than a complete solar cycle, and the heliospheric imagers SMEI (2003 – 2011 and the HIs (operating since early 2007 have provided us with the capability to image and track CMEs continually across the inner heliosphere. We review some key coronal properties of CMEs, their source regions and their propagation through the solar wind. The LASCO coronagraphs routinely observe CMEs launched along the Sun-Earth line as halo-like brightenings. STEREO also permits observing Earth-directed CMEs from three different viewpoints of increasing azimuthal separation, thereby enabling the estimation of their three-dimensional properties. These are important not only for space weather prediction purposes, but also for understanding the development and internal structure of CMEs since we view their source regions on the solar disk and can measure their in-situ characteristics along their axes. Included in our discussion of the recent developments in CME

  1. Evaluation of trace element concentration in cancerous and non-cancerous tissues of human stomach.

    Science.gov (United States)

    Kohzadi, Shadi; Sheikhesmaili, Farshad; Rahehagh, Ramesh; Parhizkar, Baran; Ghaderi, Ebrahim; Loqmani, Hozan; Shahmoradi, Behzad; Mohammadi, Ebrahim; Maleki, Afshin

    2017-10-01

    Gastric cancer has a high mortality rate in west of Iran. Various environmental elements are proposed as cancer risk factors including trace elements. Trace elements can induce initiation or progression of carcinogenesis via oxidative stress and DNA injury. The aim of this study was to measure and compare some trace element concentration (Ca, Cu, Fe, As, Mg, Ni, Cd and Cr) in gastric cancer tissues and normal tissues. For this purpose, 35 patients with gastric cancer and 30 without any cancer were biopsied. Biopsies were taken from cancerous tissue and non-cancerous tissue of gastric cancer patients and gastric tissue of normal patients. The analysis of trace elements was performed using Inductively coupled plasma mass spectrometry (ICP-MS). Data analysis was carried out using SPSS and STATA 12 software. The research found that the concentrations of Fe, Mg, and As were higher in cancerous tissues compared with non-cancerous tissues whereas Cr, Cu, Ca, and Ni concentrations were higher in non-cancerous tissues of cancerous patients. When comparisons were made for cancer and normal samples, copper was the only metal, which was significantly higher in cancerous samples (p elements may have carcinogenic effects, although further study is suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Uptake of atmospheric trace gases by organic films: experiment and modelling

    Science.gov (United States)

    Donaldson, D. J.; Demou, E.; Visram, H.; Makar, P. A.; Chaudhuri, S. R.

    2003-04-01

    The presence of large mass fractions of organic compounds in atmospheric particles impacts both on the cloud-condensation nucleating abilities of these particle and on the sequesterization of trace atmospheric gases by them. We are using thin (a few micrometers thick) organic films as model laboratory substrates for studying the sequesterization of trace gases in a controlled fashion. I will describe our results on the uptake of water and of trace organic species onto organic films containing a range of functional groups, using a combination of experimental and absorptive partitioning calculations. The uptake of water onto organic films is measured using a quartz crystal microbalance; uptake of trace organics is studied in a newly built Knudsen cell apparatus. Gas-condensed phase modelling using UNIFAC predicts the water uptake curves for some partially oxidized substrates (1-octanol, octanoic acid, 1,5 dipentanol) moderately well, but has much lower accuracy for dodecane, malonic acid or 1,8 dioctanol. Quantitative comparisons of the model with measurements will be presented, and the causes for the differences in accuracy will be discussed.

  3. Distribution and transfer of trace metals in the Aegean Seawater (Eastern Mediterranean Basin

    Directory of Open Access Journals (Sweden)

    F. VOUTSINOU-TALIADOURI

    2000-12-01

    Full Text Available Recent measurements of dissolved Cd, Cu, Ni and Mn in 324 water samples of the Aegean Sea fill the gap of missing knowledge in this part of the Eastern Mediterranean and try to identify their main input sources and spreading pathways. The analyses indicate that trace metal concentrations in the North and South Aegean Sea are generally in good agreement with those reported for the Western Mediterranean Sea. In the North Aegean Sea the trace metal distribution patterns differentiate mainly according to the existing water masses. Hence, a strong influence of the Black Sea Water, enriched in trace metals, is clearly recorded for Mn. Concentrations of this metal are one order of magnitude higher in the surface layer than those of the deeper waters. This feature is followed to a lesser degree also by Cd, Cu and Ni. Trace metal concentrations in the South Aegean Sea reveal almost constant values throughout the watercolumn similar to those observed in the North Aegean Sea below the depth of 100 m. Manganese values in the South Aegean Sea are considerably lower comparing with the North Aegean ones, showing relatively enhanced surface values which decrease with depth.

  4. Development of a new method for hydrogen isotope analysis of trace hydrocarbons in natural gas samples

    Directory of Open Access Journals (Sweden)

    Xibin Wang

    2016-12-01

    Full Text Available A new method had been developed for the analysis of hydrogen isotopic composition of trace hydrocarbons in natural gas samples by using solid phase microextraction (SPME combined with gas chromatography-isotope ratio mass spectrometry (GC/IRMS. In this study, the SPME technique had been initially introduced to achieve the enrichment of trace content of hydrocarbons with low abundance and coupled to GC/IRMS for hydrogen isotopic analysis. The main parameters, including the equilibration time, extraction temperature, and the fiber type, were systematically optimized. The results not only demonstrated that high extraction yield was true but also shows that the hydrogen isotopic fractionation was not observed during the extraction process, when the SPME device fitted with polydimethylsiloxane/divinylbenzene/carbon molecular sieve (PDMS/DVB/CAR fiber. The applications of SPME-GC/IRMS method were evaluated by using natural gas samples collected from different sedimentary basins; the standard deviation (SD was better than 4‰ for reproducible measurements; and also, the hydrogen isotope values from C1 to C9 can be obtained with satisfying repeatability. The SPME-GC/IRMS method fitted with PDMS/DVB/CAR fiber is well suited for the preconcentration of trace hydrocarbons, and provides a reliable hydrogen isotopic analysis for trace hydrocarbons in natural gas samples.

  5. Solid-phase extraction microfluidic devices for matrix removal in trace element assay of actinide materials.

    Science.gov (United States)

    Gao, Jun; Manard, Benjamin T; Castro, Alonso; Montoya, Dennis P; Xu, Ning; Chamberlin, Rebecca M

    2017-05-15

    Advances in sample nebulization and injection technology have significantly reduced the volume of solution required for trace impurity analysis in plutonium and uranium materials. Correspondingly, we have designed and tested a novel chip-based microfluidic platform, containing a 100-µL or 20-µL solid-phase microextraction column, packed by centrifugation, which supports nuclear material mass and solution volume reductions of 90% or more compared to standard methods. Quantitative recovery of 28 trace elements in uranium was demonstrated using a UTEVA chromatographic resin column, and trace element recovery from thorium (a surrogate for plutonium) was similarly demonstrated using anion exchange resin AG MP-1. Of nine materials tested, compatibility of polyvinyl chloride (PVC), polypropylene (PP), and polytetrafluoroethylene (PTFE) chips with the strong nitric acid media was highest. The microcolumns can be incorporated into a variety of devices and systems, and can be loaded with other solid-phase resins for trace element assay in high-purity metals. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Trace metals in the estuary of the Seine and its approaches

    International Nuclear Information System (INIS)

    Boust, Dominique

    1981-01-01

    The distribution and behaviour of trace metals (Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Ti, V and Zn) were studied in the waters and deposited or suspended sediments of the estuary and eastern bay of the Seine river. The various physico-chemical forms - hydrosoluble, exchangeable, chelated, organic forms, were determined by successive fractionations. The abundance of the ionic stock in the estuary cannot explain the decrease of trace metal contents by purely chemical processes. Mixing processes with open sea particles and release of metals induced by the erosion-sedimentation cycles resulting in sediment washing can explain the observations. Metals first trapped in the sediments are freed in the dissolved state; they can be expelled from the estuary and participate in the biological cycles. In the bay sediments, the trace metals were used as tracers of sediment masses, allowing to determine the river deposit areas. The human contribution to trace metal deposits in the Seine river bay was also estimated. (author) [fr

  7. Molecular Speciation of Trace Metal Organic Complexes in the Pacific Ocean

    Science.gov (United States)

    Repeta, D.; Boiteau, R. M.; Bundy, R. M.; Babcock-Adams, L.

    2017-12-01

    Microbial production across approximately one third of the surface ocean is limited by extraordinarily low (picomolar) concentrations of dissolved iron, essentially all of which is complexed to strong organic ligands of unknown composition. Other biologically important trace metals (cobalt, copper, zinc, nickel) are also complexed to strong organic ligands, which again have not been extensively characterized. Nevertheless, organic ligands exert a strong influence on metal bioavailability and toxicity. For example, amendment experiments using commercially available siderophores, organic compounds synthesized by microbes to facilitate iron uptake, show these ligands can both facilitate or impede iron uptake depending on the siderophore composition and available uptake pathways. Over the past few years we have developed analytical techniques using high pressure liquid chromatography interfaced with inductively coupled plasma and electrospray ionization mass spectrometry to identify and quantify trace metal organic complexes in laboratory cultures of marine microbes and in seawater. We found siderophores to be widely distributed in the ocean, particularly in regions characterized by low iron concentrations. We also find chemically distinct complexes of copper, zinc, colbalt and nickel that we have yet to fully characterize. We will discuss some of our recent work on trace metal organic speciation in seawater and laboratory cultures, and outline future efforts to better understand the microbial cycling of trace metal organic complexes in the sea.

  8. In-situ dating of the Earth's oldest trace fossil at 3.34 Ga

    Science.gov (United States)

    Fliegel, D.; Kosler, J.; McLoughlin, N.; Simonetti, A.; de Wit, M. J.; Wirth, R.; Furnes, H.

    2010-11-01

    Microbial activity in volcanic glass within the oceanic crust can produce micron sized pits and tunnels. Such biogenic textures have been described from the recent oceanic crust and mineralized equivalents in pillow lavas as old as 3.47-3.45 Ga from the Barberton Greenstone Belt (BGB) of South Africa. In meta-volcanic glasses these microbial traces are preserved by titanite mineralization (CaTiSiO 5) and on the basis of morphological, textural and geochemical evidence have been argued to represent Earth's oldest trace fossils. Here we report the results of in-situ U-Pb dating of titanite that infills trace fossils from the Hooggenoeg Complex of the BGB using laser ablation MC-ICP-MS (multi-collector inductively coupled, plasma mass spectrometry). This yields a titanite age of 3.342 ± 0.068 Ga demonstrating the antiquity of the BGB trace fossils. This radiometric age confirms that a sub-seafloor biosphere was already established in the PaleoArchean and that it likely represented an important habitat for the emergence and evolution of early microbial life on the Earth.

  9. Offshore iron sand extraction in New Zealand: Potential trace metal exposure of benthic and pelagic biota.

    Science.gov (United States)

    Vopel, Kay; Pook, Chris; Wilson, Peter; Robertson, John

    2017-10-15

    Plans to exploit an offshore source of iron sand in South Taranaki Bight (STB), New Zealand, caused concerns that such exploitation may expose benthic and pelagic biota to elevated trace metal concentrations. We conducted dilute-acid extractions and standard elutriate tests to investigate the potential of this exploitation to (1) create a new seafloor with elevated trace metal content, (2) mobilise trace metals during iron sand extraction and, (3) enrich the returning process seawater, which feeds iron sand through mills, with trace metals. We found that recruits of freshly uncovered sediment may encounter higher-than-natural concentrations of cadmium, nickel and chromium (but not of copper, lead, and zinc) and propose to investigate the bioavailability of these metals. Elutriate test with raw and milled iron sand revealed that, for nickel and copper, dilution of the process seawater may be required to meet the local water quality guideline. We argue that this dilution can be achieved by adjustment of the mass and seawater balance of the offshore extraction process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Use of trace elements as indicators for underground fluid circulations in karstic environment

    International Nuclear Information System (INIS)

    Pane-Escribe, M.B.

    1995-01-01

    The geochemical study of the trace element behaviour in karstic groundwaters has been carried out over the experimental site of Lamalou (Herault, France). Routine measurements of the physico-chemical parameters and of the dissolved elements concentrations have been achieved during two hydrological cycles. Radon has been monitored by passive detectors and by automatic electronic probes. Trace elements (Sc, Ti, V, Cr, Ni, Cu, Zn, As Rb, Sr, Mo, Cd, Sb, Cs, Ba, Th, U) were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The first part of this work presents the methodologies employed with in particular the improvement of the analytical performances of ICP-MS for water samples analysis. The detection limit for each considered element has been determined. The short and long term reproducibility for the samples analysis has also been tested. The second part of this study presents the treatment and interpretation of the results. This analysis has pointed our the influence of the aquifer structure on the chemical elements distribution. The trace and major elements concentrations are effectively related to the fracturing state of the reservoir and allow to individualize the high transmissivity zones from zones with a lower transmissivity in this mono-lithological context, trace elements appear to be particularly efficient tracers for determining the water origin and circulation their spatial and temporal behaviour leads to identify three different origins for the water mineralization over the studied area: limestones, clays and external sources (rainfalls and occasional pollutions). (author)

  11. Input of trace substances to coniferous forests by fog interception at high elevations of Black Forest

    International Nuclear Information System (INIS)

    Winkler, P.; Pahl, S.

    1993-10-01

    The deposition of trace substances to a coniferous forest has been estimated by means of a one-dimensional cloud droplet deposition model. For a period of 21 months the liquid water content has been measured and 89 samples of cloud water from the weather station Feldberg have been analysed for chemical composition. These data and meteorological routine observations have been used as input parameters for the deposition model. Deposition calculations to a 40 years old coniferous forest for the period 1982-1991 showed that the cloud water deposition amounts to 33% of the precipitation amount on the average and varies between 23 and 43% in single years. The highest cloud water deposition rates occur during fall and winter. The trace substance concentration in cloud water has been found to be higher than in precipitation, by a factor between 6 and 12, depending on the type of ions. Typically seasonal variations of normalized ion concentrations could be shown to exist as well as dependencies on wind direction. Air mass transport from the industries of the Stuttgart area resulted in higher trace substance concentrations in cloud water. The deposition of trace substances via fog interception during the summer months is as high and in the winter months higher than that by wet deposition. The forests at high elevations of Black Forest are charged appreciably by fog interception. (orig.). 31 figs., 5 tabs., 39 refs [de

  12. Speciation of selected trace elements in three Ethiopian Rift Valley Lakes (Koka, Ziway, and Awassa) and their major inflows

    International Nuclear Information System (INIS)

    Masresha, Alemayehu E.; Skipperud, Lindis; Rosseland, Bjorn Olav; Zinabu, G.M.; Meland, Sondre; Teien, Hans-Christian; Salbu, Brit

    2011-01-01

    The Ethiopian Rift Valley Lakes (ERVLs) are water resources which have considerable environmental, economic and cultural importance. However, there is an increasing concern that increasing human activities around these lakes and their main inflows can result in increased contamination of these water bodies. Information on total concentrations of some trace elements is available for these lakes and their inflows; however, data on the trace element speciation is lacking. Therefore, the objective of this study was to determine the low molecular mass (LMM) trace element species and also, evaluate the influence of flooding episodes on the LMM trace element fractions. At-site size and charge fractionation system was used for sampling of water from the lakes Koka, Ziway and Awassa and their main inflows during the dry and wet seasons. The results showed that chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and lead (Pb) in Lake Koka and its inflows as well as in Lake Ziway were predominantly present as HMM (high molecular mass, i.e., > 10 kDa) forms, while arsenic (As), selenium (Se), cadmium (Cd) were more mobile during the dry season. In Lake Awassa, all except Cr and Mn were predominantly found as LMM species (low molecular mass, i.e. < 10 kDa) which can be attributed to the high concentrations of LMM DOC (dissolved organic carbon). During the wet season, results from the Lake Koka and its inflows showed that all trace elements were predominantly associated with HMM forms such as colloids and particles, demonstrating that the mobility of elements was reduced during the wet season. The colloidal fraction of elements such as Cr, Ni, and Cd was also correlated with dissolved Fe. As the concentration of LMM trace element species are very low, the mobility, biological uptake and the potential environmental impact should be low.

  13. Present and Future Challenges in Trace and Ultra-Trace Analysis

    International Nuclear Information System (INIS)

    Toulhoat, P.

    2005-01-01

    The analysis of trace and ultra-trace elements is continuously stimulating the progress in analytical chemistry. Environmental chemistry, radiochemistry, biology, health, agri-food are prescribers of trace analyses, with continuously increasing exigencies: lowering detection limits, lowering costs and analysis time, improving the quality of analytical information. Precise data about the chemical identity and chemical environment of analytes are now requested. Such pieces of information, beyond simple numerical data and confidence intervals, are necessary to understand studied systems, and to predict their evolution. From environmental contamination cases, one can envisage the various aspects of a problem, with for each of them its own exigencies and specificities in terms of analytical methods and approaches. The detection of traces and ultra-traces of actinides and fission products has been recently revisited and stimulates new technological developments (non proliferation issues, waste management). Data on their speciation in geological and biological media are essential for evaluating the safety of nuclear waste repositories. Various techniques are now used to determine speciation in liquid samples or on surfaces, with tremendous spatial resolutions or sensitivities. A new revolution in analytical chemistry is expected with the development of micro- or nano-analytical technologies. (author)

  14. Trace minerals and livestock: not too much not too little.

    Science.gov (United States)

    López-Alonso, Marta

    2012-01-01

    The new approaches of the animal production systems make managing the mineral nutrition a challenge. Versus the excessive, trace mineral supply in intensively managed livestock, well above the physiological requirements, is the no trace mineral supplementation of organic systems, which become highly dependent on trace minerals in the soil. Nowadays, in addition to the animal health perspective, trace mineral nutrition must be environment friendly and allow getting mineral-enriched animal products. We are in a new scenario, where a balance between animal trace mineral needs and limits is needed. This papers focuses on different aspects that will help us to enter a critical dialogue in relation to animal-human-environment.

  15. Classification of conductance traces with recurrent neural networks.

    Science.gov (United States)

    Lauritzen, Kasper P; Magyarkuti, András; Balogh, Zoltán; Halbritter, András; Solomon, Gemma C

    2018-02-28

    We present a new automated method for structural classification of the traces obtained in break junction experiments. Using recurrent neural networks trained on the traces of minimal cross-sectional area in molecular dynamics simulations, we successfully separate the traces into two classes: point contact or nanowire. This is done without any assumptions about the expected features of each class. The trained neural network is applied to experimental break junction conductance traces, and it separates the classes as well as the previously used experimental methods. The effect of using partial conductance traces is explored, and we show that the method performs equally well using full or partial traces (as long as the trace just prior to breaking is included). When only the initial part of the trace is included, the results are still better than random chance. Finally, we show that the neural network classification method can be used to classify experimental conductance traces without using simulated results for training, but instead training the network on a few representative experimental traces. This offers a tool to recognize some characteristic motifs of the traces, which can be hard to find by simple data selection algorithms.

  16. Classification of conductance traces with recurrent neural networks

    Science.gov (United States)

    Lauritzen, Kasper P.; Magyarkuti, András; Balogh, Zoltán; Halbritter, András; Solomon, Gemma C.

    2018-02-01

    We present a new automated method for structural classification of the traces obtained in break junction experiments. Using recurrent neural networks trained on the traces of minimal cross-sectional area in molecular dynamics simulations, we successfully separate the traces into two classes: point contact or nanowire. This is done without any assumptions about the expected features of each class. The trained neural network is applied to experimental break junction conductance traces, and it separates the classes as well as the previously used experimental methods. The effect of using partial conductance traces is explored, and we show that the method performs equally well using full or partial traces (as long as the trace just prior to breaking is included). When only the initial part of the trace is included, the results are still better than random chance. Finally, we show that the neural network classification method can be used to classify experimental conductance traces without using simulated results for training, but instead training the network on a few representative experimental traces. This offers a tool to recognize some characteristic motifs of the traces, which can be hard to find by simple data selection algorithms.

  17. Offset Trace-Based Video Quality Evaluation Network Transport

    DEFF Research Database (Denmark)

    Seeling, P.; Reisslein, M.; Fitzek, Frank

    2006-01-01

    Video traces contain information about encoded video frames, such as frame sizes and qualities, and provide a convenient method to conduct multimedia networking research. Although wiedely used in networking research, these traces do not allow to determine the video qaulityin an accurate manner...... after networking transport that includes losses and delays. In this work, we provide (i) an overview of frame dependencies that have to be taken into consideration when working with video traces, (ii) an algorithmic approach to combine traditional video traces and offset distortion traces to determine...... the video quality or distortion after lossy network transport, (iii) offset distortion and quality characteristics and (iv) the offset distortion trace format and tools to create offset distortion traces....

  18. Trace-based post-silicon validation for VLSI circuits

    CERN Document Server

    Liu, Xiao

    2014-01-01

    This book first provides a comprehensive coverage of state-of-the-art validation solutions based on real-time signal tracing to guarantee the correctness of VLSI circuits.  The authors discuss several key challenges in post-silicon validation and provide automated solutions that are systematic and cost-effective.  A series of automatic tracing solutions and innovative design for debug (DfD) techniques are described, including techniques for trace signal selection for enhancing visibility of functional errors, a multiplexed signal tracing strategy for improving functional error detection, a tracing solution for debugging electrical errors, an interconnection fabric for increasing data bandwidth and supporting multi-core debug, an interconnection fabric design and optimization technique to increase transfer flexibility and a DfD design and associated tracing solution for improving debug efficiency and expanding tracing window. The solutions presented in this book improve the validation quality of VLSI circuit...

  19. Miniaturized Hollow-Waveguide Gas Correlation Radiometer (GCR) for Trace Gas Detection in the Martian Atmosphere

    Science.gov (United States)

    Wilson, Emily L.; Georgieva, E. M.; Melroy, H. R.

    2012-01-01

    Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Here, we present a miniaturized and simplified version of this instrument capable of mapping multiple trace gases and identifying active regions on the Mars surface. Reduction of the size and mass of the GCR instrument has been achieved by implementing a lightweight, 1 mm inner diameter hollow-core optical fiber (hollow waveguide) for the gas correlation cell. Based on a comparison with an Earth orbiting CO2 gas correlation instrument, replacement of the 10 meter mUltipass cell with hollow waveguide of equivalent pathlength reduces the cell mass from approx 150 kg to approx 0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately I meter in diameter by 0.05 m in height (mass and volume reductions of >99%). This modular instrument technique can be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance.

  20. Major and Trace Element Analysis of Natural and Experimental Igneous Systems using LA-ICP-MS

    Science.gov (United States)

    Jenner, Frances E.; Arevalo, Ricardo D., Jr.

    2016-01-01

    Major- and trace-element compositions of minerals provide valuable information on a variety of global Earth-system processes, including melting of distinct mantle reservoirs, the growth and evolution of the Earths crust and the formation of economically viable ore deposits. In the mid-1980s and early 1990s, attempts were made to couple laser ablation (LA) systems to inductively coupled plasma mass spectrometry (ICPMS) instruments (e.g. Fryer et al. 1995; Jackson et al. 1992). The goal was to develop a rapid, highly sensitive in situ analytical technique to measure abundances and spatial distributions of trace elements in minerals and other geological samples. Elemental analysis using LAICPMS was envisaged as a quicker and less destructive means of chemical analysis (requiring only g quantities) than labour-intensive sample digestion and solution analysis (requiring mg-levels of material); and it would be a more cost-effective method than secondary ion mass spectrometry (SIMS) for the routine analysis of trace elements from solid samples. Furthermore, it would have lower limits-of-detection than electron probe microanalysis (EPMA) (e.g. Jackson et al. 1992; Eggins 2003).

  1. Trace Element Levels in Congenital Hypogonadotrophic Hypogonadism.

    Science.gov (United States)

    Aydogdu, A; Haymana, C; Soykut, B; Erdem, O; Basaran, Y; Baskoy, K; Dinc, M; Taslipinar, A; Sonmez, A; Bolu, E; Azal, O

    2016-05-01

    Cardiometabolic diseases are prevalent in hypogonadism. The pathophysiologic mechanism of increased cardiometabolic risk in hypogonadal patients is not clear. Recently, trace elements have been linked to the development of chronic disease especially cardiovascular disease. We investigated the trace element levels in an unconfounded population of congenital hypogonadotrophic hypogonadism (CHH) and also searched for the relationship with metabolic risk factors. A total of 89 patients with CHH (mean age 21.8 ± 2.0 years) and 80 healthy control subjects (mean age 21.3 ± 1.1 years) were enrolled. The demographic parameters, homeostatic model assessment of insulin resistance (HOMA-IR) levels and plasma zinc, copper, and selenium levels, were measured in patients and healthy controls. The patients had higher waist circumferences (p = 0.014), triglyceride (p = 0.04), insulin (p = 0.004), HOMA-IR levels (p = 0.001), and lower selenium (p = 0.049), zinc (p = 0.004), and copper (p = 0.012) levels when compared to the healthy controls. There was a significant relationship between zinc levels and HOMA-IR levels (p = 0.015). In the regression analysis, zinc levels were independently associated with the calculated HOMA-IR levels (p = 0.015). The results of the present study show that plasma selenium, zinc, and copper levels are decreased in patients with CHH. Also, plasma zinc levels are independently associated with insulin resistance in patients with hypogonadism. Long-term follow-up studies are warranted to investigate the effect of trace elements on the increased cardiometabolic risk in hypogonadism.

  2. Ultra-Trace Analysis of Krypton-85

    International Nuclear Information System (INIS)

    Daerr, H.; Kalinowski, M.; Kohler, M.; Sahling, P.

    2010-01-01

    To strengthen the efficiency and effectiveness of nuclear safeguards for detecting undeclared nuclear material and activities we propose to use the radioactive krypton isotope Krypton-85 as a tracer for clandestine plutonium production. The main idea is to detect inexplicable atmospheric Kr85 concentration using the novel technology atom trap trace analysis (ATTA) in order to detect an undeclared reprocessing facility. The Additional Protocol (INFCIRC/540, 1997) establishes the possibility to take environmental samples. Krypton-85 has a combination of unique features which makes it an ideal tracer for plutonium separation activities anywhere in the world. It is always generated along with plutonium and 99.9% remains within the fuel cladding. Due to its half-life of 10.76 years, significant amounts of krypton-85 still remain in the spent fuel even after long cooling times. Krypton is not removed from the atmosphere by any processes like chemical reactions or wash-out. Furthermore, there are no other relevant sources of krypton-85 besides of reprocessing. The novel technology of atom trap trace analysis (ATTA) has been demonstrated by the physics group at Argonne National Laboratory in 1999. This is an ultra-sensitive trace analysis technique able to detect single krypton atoms. We are setting up an ATTA apparatus in our laboratory, which is designed to fulfill all requirements to detect clandestine plutonium production. Our goal is to determine Krypton-85 concentration of one liter samples of atmospheric air with an analysis time of 3 hours. This sample volume reduction is a significant step, since one liter can be taken as a grab sample by sucking it directly into pre-evacuated bottles at atmospheric pressure. The small samples size and the short analysis time of ATTA will make it possible to use krypton-85 as a tracer for clandestine plutonium production with routine operation. (author)

  3. Tracing Magnetic Fields with Spectroscopic Channel Maps

    Science.gov (United States)

    Lazarian, A.; Yuen, Ka Ho

    2018-01-01

    We identify velocity channel map intensities as a new way to trace magnetic fields in turbulent media. This work makes use of both the modern theory of magnetohydrodynamic (MHD) turbulence, which predicts that magnetic eddies are aligned with the local direction of the magnetic field, and also the theory of spectral line position–position–velocity (PPV) statistics, which describes how velocity and density fluctuations are mapped onto PPV space. In particular, we use the fact that the fluctuations of the intensity of thin channel maps are mostly affected by the turbulent velocity, while the thick maps are dominated by density variations. We study how contributions of the fundamental MHD modes affect the Velocity Channel Gradients (VChGs), and demonstrate that the VChGs arising from Alfvén and slow modes are aligned perpendicular to the local direction of the magnetic field, while the VChGs produced by the fast mode are aligned parallel to the magnetic field. The dominance of Alfvén and slow modes in interstellar media will therefore allow reliable magnetic field tracing using the VChGs. We explore ways of identifying self-gravitating regions that do not require polarimetric information. In addition, we also introduce a new measure, termed “Reduced Velocity Centroids” (RVCGs), and compare its abilities with those of VChGs. We employed VChGs in analyzing GALFA 21 cm data and successfully compared the magnetic field directions with the Planck polarization observations. The applications of the suggested techniques include both tracing the magnetic field in diffuse interstellar media and star-forming regions, and removing the galactic foreground in the framework of cosmological polarization studies.

  4. Traces of evidence. Nuclear forensics and illicit trafficking

    International Nuclear Information System (INIS)

    Koch, L.

    2003-01-01

    or public threat. If needed, scientists from the concerned States will characterize the material, together with the assistance of nuclear forensics experts at the ITU, to find out the intended use, origin and smuggling route of the seized material. The investigation scheme for nuclear or radioactive material is not very different from classical forensics. Before preserving the evidence, officers take the necessary precautions to protect themselves and the public (under observation of the chain of custody required for that State). Traces (fibres, dust, DNA, fingerprints etc.) from contaminated surfaces are best collected in appropriate laboratories. Nuclear forensics provides valuable clues based on the fact that in each nuclear or radioactive material the isotopic composition of ingoing chemical elements, and differs from that in naturally occurring elements. Nuclear forensics can rely on a variety of established and recognized methods. The analytical instrumentation and procedures used in the fabrication of radioactive and nuclear materials are not only appropriate but also indispensable to obtain information of similar quality to compare with historical plant records. Tools of Analytical Techniques are the most common analytical techniques in use. They are grouped by tools related to: measuring weight and dimensions of materials, e.g. of a fuel pellet; determining the abundance of the main nuclides, e.g. enrichment of U-235; analysing the chemical composition; describing the microstructure; and assay of impurities. In order to compare with available but very specific historical data, the nuclear forensics expert sometimes requires special analyses such as the surface roughness of fuel, grain size etc. As in classical forensics and geo-cosmology, nuclear forensics employs chemical analysis as well as optical and electron microscopy. Of particular importance are mass spectrometric techniques. Some of these are also common in trace analysis of natural elements (e

  5. Dietary patterns and trace elements intake evaluation

    International Nuclear Information System (INIS)

    Rahman, A.; Waheed, S.; Zaidi, J.H.; Ahmad, S.

    1998-01-01

    The dietary patterns and trace element contents of the integrated diets of middle income population in Gujranwala and of Islamabad have been studied and dietary intake of winter and summer are given. An overview of the elemental concentration in the two sets of integrated diets reveals similar zinc and manganese concentrations; comparatively higher nickel, selenium and potassium concentrations in Gujranwala and higher chromium, cesium, scandium, sodium and chlorine concentrations in Islamabad. These results undoubtedly reflect the difference in food selection and habits of the two populations, the influence of soil content and industrial pollution

  6. Molecular tracing of VHS in Denmark

    DEFF Research Database (Denmark)

    Mikkelsen, Susie Sommer; Schuetze, H.; Korsholm, H.

    2015-01-01

    and scenario-simulation models to identify important factors for the spread of disease and to develop and evaluate new control strategies. Viral haemorrhagic septicaemia Virus (VHSV) is one of the most important viral fish diseases and is widely spread all over Europe and creates significant losses every year...... in Denmark and to look into the spread of the disease over a historical period as well as the effectiveness of containment and eradication programmes. Molecular tracing shows that the numerous VHS outbreaks in marine fish farms were due to stocking these with VHS infected rainbow trout in the incubation...

  7. Sodium Exosphere of Planet Mercury: Particle Tracing

    Science.gov (United States)

    Paral, J.; Travnicek, P.; Kabin, K.; Rankin, R.

    2007-12-01

    We will present the results of particle tracing simulations of heavy ions in magnetosphere of Mercury. In our study we use electric and magnetic fields from self-consistent hybrid simulations of Hermean environment. We consider three major release processes, namely photon stimulated description, solar wind sputtering, and micro-meteoroid vaporization to study distribution of energy and other characteristics in space and time. The released neutral atoms are ionized through photoionization processes after the sputtering. Part of our work will be focused on the possible measurements during three initial flybys of the MESSENGER spacecraft scheduled for 2008 and 2009.

  8. Method for detecting trace impurities in gases

    Science.gov (United States)

    Freund, S.M.; Maier, W.B. II; Holland, R.F.; Beattie, W.H.

    A technique for considerably improving the sensitivity and specificity of infrared spectrometry as applied to quantitative determination of trace impurities in various carrier or solvent gases is presented. A gas to be examined for impurities is liquefied and infrared absorption spectra of the liquid are obtained. Spectral simplification and number densities of impurities in the optical path are substantially higher than are obtainable in similar gas-phase analyses. Carbon dioxide impurity (approx. 2 ppM) present in commercial Xe and ppM levels of Freon 12 and vinyl chloride added to liquefied air are used to illustrate the method.

  9. Trace of nuclear energy with pictures

    International Nuclear Information System (INIS)

    1992-05-01

    This book traces the history of development over nuclear energy with pictures, which contains preface, development history of the world, development history of Korea, nuclear power plant in Kori, nuclear power plant in Wolseong, nuclear power plant in Yeonggwang, nuclear power plant in Uljin, nuclear fuel, using of radiation and radioactive isotope, development of nuclear energy in the world and a Chronological table of nuclear energy. This book is written to record the development history of Korea through pictures of the nuclear power plants in Korea.

  10. Tracing monadic computations and representing effects

    Directory of Open Access Journals (Sweden)

    Maciej Piróg

    2012-02-01

    Full Text Available In functional programming, monads are supposed to encapsulate computations, effectfully producing the final result, but keeping to themselves the means of acquiring it. For various reasons, we sometimes want to reveal the internals of a computation. To make that possible, in this paper we introduce monad transformers that add the ability to automatically accumulate observations about the course of execution as an effect. We discover that if we treat the resulting trace as the actual result of the computation, we can find new functionality in existing monads, notably when working with non-terminating computations.

  11. 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

  12. RAY TRACING RENDER MENGGUNAKAN FRAGMENT ANTI ALIASING

    Directory of Open Access Journals (Sweden)

    Febriliyan Samopa

    2008-07-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Rendering is generating surface and three-dimensional effects on an object displayed on a monitor screen. Ray tracing as a rendering method that traces ray for each image pixel has a drawback, that is, aliasing (jaggies effect. There are some methods for executing anti aliasing. One of those methods is OGSS (Ordered Grid Super Sampling. OGSS is able to perform aliasing well. However, this method requires more computation time since sampling of all pixels in the image will be increased. Fragment Anti Aliasing (FAA is a new alternative method that can cope with the drawback. FAA will check the image when performing rendering to a scene. Jaggies effect is only happened at curve and gradient object. Therefore, only this part of object that will experience sampling magnification. After this sampling magnification and the pixel values are computed, then downsample is performed to retrieve the original pixel values. Experimental results show that the software can implement ray tracing well in order to form images, and it can implement FAA and OGSS technique to perform anti aliasing. In general, rendering using FAA is faster than using OGSS

  13. Mass Customization Services

    DEFF Research Database (Denmark)

    Friedrich, Gerhard

    Topics of the IMCM’08 & PETO’08 and this book are: Mass customization in service, mass customizing financial services, mass customization in supply networks, implementation issues in logistics, product life cycle and mass customization. The research field of mass customization is more than 15 years...

  14. Mass spectrometry of long-lived radionuclides

    International Nuclear Information System (INIS)

    Becker, Johanna Sabine.

    2003-01-01

    The capability of determining element concentrations at the trace and ultratrace level and isotope ratios is a main feature of inorganic mass spectrometry. The precise and accurate determination of isotope ratios of long-lived natural and artificial radionuclides is required, e.g. for their environmental monitoring and health control, for studying radionuclide migration, for age dating, for determining isotope ratios of radiogenic elements in the nuclear industry, for quality assurance and determination of the burn-up of fuel material in a nuclear power plant, for reprocessing plants, nuclear material accounting and radioactive waste control. Inorganic mass spectrometry, especially inductively coupled plasma mass spectrometry (ICP-MS) as the most important inorganic mass spectrometric technique today, possesses excellent sensitivity, precision and good accuracy for isotope ratio measurements and practically no restriction with respect to the ionization potential of the element investigated--therefore, thermal ionization mass spectrometry (TIMS), which has been used as the dominant analytical technique for precise isotope ratio measurements of long-lived radionuclides for many decades, is being replaced increasingly by ICP-MS. In the last few years instrumental progress in improving figures of merit for the determination of isotope ratio measurements of long-lived radionuclides in ICP-MS has been achieved by the application of a multiple ion collector device (MC-ICP-MS) and the introduction of the collision cell interface in order to dissociate disturbing argon-based molecular ions, to reduce the kinetic energy of ions and neutralize the disturbing noble gas ions (e.g. of 129 Xe + for the determination of 129 I). The review describes the state of the art and the progress of different inorganic mass spectrometric techniques such as ICP-MS, laser ablation ICP-MS vs. TIMS, glow discharge mass spectrometry, secondary ion mass spectrometry, resonance ionization mass

  15. Microbeam AMS measurements of PGE and Au trace and osmium isotopic ratios

    International Nuclear Information System (INIS)

    Sie, S.H.; Sims, D.A.; Suter, G.F.

    2001-01-01

    The microbeam Accelerator Mass Spectrometry (AMS) system, AUSTRALIS (AMS for Ultra Sensitive TRAce eLement and Isotopic Studies) at CSIRO Heavy Ion Analytical Facility (HIAF) has been used to measure trace levels of precious metals, the platinum group elements (PGE) and Au, from an assortment of geological and meteoritic samples with spatial resolution of 30 micrometres. For Au, detection sensitivity as low as sub parts per billion has been obtained, which will be of great benefit in studies of ore deposit mineralogy and mineral processing. We have also demonstrated the facility for osmium isotope measurements in meteorite samples, opening up the possibility of widespread use of the Re-Os system in exploration programs

  16. The evolution of complex type B Allende inclusion - An ion microprobe trace element study

    Science.gov (United States)

    Macpherson, Glenn J.; Crozaz, Ghislaine; Lundberg, Laura L.

    1989-01-01

    Results are presented of a detailed trace-element and isotopic analyses of the constituent phases in each of the major textural parts (mantle, core, and islands) of a Type B refractory inclusion, the USNM 5241 inclusion from Allende, first described by El Goresy et al. (1985). The REE data on 5241 were found to be largely consistent with a model in which the mantle and the core of 5241 formed sequentially out of a single melt by fractional crystallization. The numerical models of REE evolution in the 5241 melt, especially that of Eu, require that a significant mass of spinel-free island material was assimilated into the evolving melt during the last half of the solidification history of 5241. The trace element results pbtained thus strongly support the interpretation of El Goresy et al. (1985) that the spinel-free islands in the 5241 are trapped xenoliths.

  17. 137Cs and relationships with major and trace elements in edible mushrooms from Mexico

    International Nuclear Information System (INIS)

    Gaso, M.I.; Segovia, N.; Cervantes, M.L.; Pena, P.; Acosta, E.; Morton, O.; Godinez, L.

    2000-01-01

    137 Cs and 40 K specific activity together with major and trace elements were determined in soil samples and in different edible wild mushroom species collected from a seminatural temperate forest ecosystem located in the central part of the Mexican Volcanic Belt. The activity measurements were made using a gamma-ray spectrometer system with a high purity germanium (HpGe) detector. The major and trace elements were determined using emission spectrography and mass spectrometry, respectively. The aggregated transfer factors for 137Cs were estimated in 30 local mushroom species collected from 1993 to 1999. Differences as large as three orders of magnitude were observed. The contribution of mushrooms for the total 137Cs dietary intake by the local population was estimated to be 37%. Mushrooms also showed to be good accumulators for Rb, Cu, Cs and Se

  18. Automated computer analysis of plasma-streak traces from SCYLLAC

    International Nuclear Information System (INIS)

    Whiteman, R.L.; Jahoda, F.C.; Kruger, R.P.

    1977-11-01

    An automated computer analysis technique that locates and references the approximate centroid of single- or dual-streak traces from the Los Alamos Scientific Laboratory SCYLLAC facility is described. The technique also determines the plasma-trace width over a limited self-adjusting region. The plasma traces are recorded with streak cameras on Polaroid film, then scanned and digitized for processing. The analysis technique uses scene segmentation to separate the plasma trace from a reference fiducial trace. The technique employs two methods of peak detection; one for the plasma trace and one for the fiducial trace. The width is obtained using an edge-detection, or slope, method. Timing data are derived from the intensity modulation of the fiducial trace. To smooth (despike) the output graphs showing the plasma-trace centroid and width, a technique of ''twicing'' developed by Tukey was employed. In addition, an interactive sorting algorithm allows retrieval of the centroid, width, and fiducial data from any test shot plasma for post analysis. As yet, only a limited set of the plasma traces has been processed with this technique

  19. Automated computer analysis of plasma-streak traces from SCYLLAC

    International Nuclear Information System (INIS)

    Whitman, R.L.; Jahoda, F.C.; Kruger, R.P.

    1977-01-01

    An automated computer analysis technique that locates and references the approximate centroid of single- or dual-streak traces from the Los Alamos Scientific Laboratory SCYLLAC facility is described. The technique also determines the plasma-trace width over a limited self-adjusting region. The plasma traces are recorded with streak cameras on Polaroid film, then scanned and digitized for processing. The analysis technique uses scene segmentation to separate the plasma trace from a reference fiducial trace. The technique employs two methods of peak detection; one for the plasma trace and one for the fiducial trace. The width is obtained using an edge-detection, or slope, method. Timing data are derived from the intensity modulation of the fiducial trace. To smooth (despike) the output graphs showing the plasma-trace centroid and width, a technique of ''twicing'' developed by Tukey was employed. In addition, an interactive sorting algorithm allows retrieval of the centroid, width, and fiducial data from any test shot plasma for post analysis. As yet, only a limited set of sixteen plasma traces has been processed using this technique

  20. Development of monitoring and control technology based on trace gas monitoring. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Liebowitz, B.

    1997-07-01

    Trace gases are generated by many biological reactions. During anaerobic decomposition, trace levels of hydrogen (H{sub 2}) and carbon monoxide (CO) gases are produced. It was shown previously that these trace gases are intrinsically related to the biochemical reactions occurring and, therefore, offer promise for on-line process monitoring and control. This work was designed to test how effectively hydrogen and CO could be to monitor high-rate anaerobic systems that has significant mass transfer and complex hydraulics. An experimental program was designed to examine the behavior of an upflow anaerobic sludge blanket (UASB) reactor system under steady state and in response to organic loading perturbations. The responses of trace gases CO and H{sub 2} were tracked using an on-line, real-time gas-monitoring system linked to a computer-controlled data acquisition package. Data on conventional process parameters such as pH, chemical oxygen demand (COD), volatile fatty acids (VFAs) were concurrently collected. Monitoring of conventional process indicators (i.e., pH, VFA, gas production) and trace gas (H{sub 2} and CO) indicators was conducted using a matrix of nine different steady-state OLRs (4-23 kg COD/m{sup 3} -d) and system HRTs (0.5 to 2.5 days) was performed to determine any correlation among the indicators. Of OLR, HRT, and influent COD, only OLR had any significant influence on the process indicators examined. All parameters except methane increased with increases in OLR; methane decreased with increased OLR. The OLR and gas production rate (GP) were observed to be linearly correlated.

  1. Selected trace elements in the Sacramento River, California: Occurrence and distribution

    Science.gov (United States)

    Taylor, Howard E.; Antweiler, Ronald C.; Roth, David A.; Dileanis, Peter D.; Alpers, Charles N.

    2012-01-01

    The impact of trace elements from the Iron Mountain Superfund site on the Sacramento River and selected tributaries is examined. The concentration and distribution of many trace elements—including aluminum, arsenic, boron, barium, beryllium, bismuth, cadmium, cerium, cobalt, chromium, cesium, copper, dysprosium, erbium, europium, iron, gadolinium, holmium, potassium, lanthanum, lithium, lutetium, manganese, molybdenum, neodymium, nickel, lead, praseodymium, rubidium, rhenium, antimony, selenium, samarium, strontium, terbium, thallium, thulium, uranium, vanadium, tungsten, yttrium, ytterbium, zinc, and zirconium—were measured using a combination of inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry. Samples were collected using ultraclean techniques at selected sites in tributaries and the Sacramento River from below Shasta Dam to Freeport, California, at six separate time periods from mid-1996 to mid-1997. Trace-element concentrations in dissolved (ultrafiltered [0.005-μm pore size]) and colloidal material, isolated at each site from large volume samples, are reported. For example, dissolved Zn ranged from 900 μg/L at Spring Creek (Iron Mountain acid mine drainage into Keswick Reservoir) to 0.65 μg/L at the Freeport site on the Sacramento River. Zn associated with colloidal material ranged from 4.3 μg/L (colloid-equivalent concentration) in Spring Creek to 21.8 μg/L at the Colusa site on the Sacramento River. Virtually all of the trace elements exist in Spring Creek in the dissolved form. On entering Keswick Reservoir, the metals are at least partially converted by precipitation or adsorption to the particulate phase. Despite this observation, few of the elements are removed by settling; instead the majority is transported, associated with colloids, downriver, at least to the Bend Bridge site, which is 67 km from Keswick Dam. Most trace elements are strongly associated with the colloid phase going

  2. Effective Tolman temperature induced by trace anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Eune, Myungseok [Sangmyung University, Department of Civil Engineering, Cheonan (Korea, Republic of); Gim, Yongwan [Sogang University, Department of Physics, Seoul (Korea, Republic of); Sogang University, Research Institute for Basic Science, Seoul (Korea, Republic of); Kim, Wontae [Sogang University, Department of Physics, Seoul (Korea, Republic of)

    2017-04-15

    Despite the finiteness of stress tensor for a scalar field on the four-dimensional Schwarzschild black hole in the Israel-Hartle-Hawking vacuum, the Tolman temperature in thermal equilibrium is certainly divergent on the horizon due to the infinite blue-shift of the Hawking temperature. The origin of this conflict is due to the fact that the conventional Tolman temperature was based on the assumption of a traceless stress tensor, which is, however, incompatible with the presence of the trace anomaly responsible for the Hawking radiation. Here, we present an effective Tolman temperature which is compatible with the presence of the trace anomaly by using the modified Stefan-Boltzmann law. Eventually, the effective Tolman temperature turns out to be finite everywhere outside the horizon, and so an infinite blue-shift of the Hawking temperature at the event horizon does not appear any more. In particular, it is vanishing on the horizon, so that the equivalence principle is exactly recovered at the horizon. (orig.)

  3. Effective Tolman temperature induced by trace anomaly

    International Nuclear Information System (INIS)

    Eune, Myungseok; Gim, Yongwan; Kim, Wontae

    2017-01-01

    Despite the finiteness of stress tensor for a scalar field on the four-dimensional Schwarzschild black hole in the Israel-Hartle-Hawking vacuum, the Tolman temperature in thermal equilibrium is certainly divergent on the horizon due to the infinite blue-shift of the Hawking temperature. The origin of this conflict is due to the fact that the conventional Tolman temperature was based on the assumption of a traceless stress tensor, which is, however, incompatible with the presence of the trace anomaly responsible for the Hawking radiation. Here, we present an effective Tolman temperature which is compatible with the presence of the trace anomaly by using the modified Stefan-Boltzmann law. Eventually, the effective Tolman temperature turns out to be finite everywhere outside the horizon, and so an infinite blue-shift of the Hawking temperature at the event horizon does not appear any more. In particular, it is vanishing on the horizon, so that the equivalence principle is exactly recovered at the horizon. (orig.)

  4. Trace Attack against Biometric Mobile Applications

    Directory of Open Access Journals (Sweden)

    Sanaa Ghouzali

    2016-01-01

    Full Text Available With the exponential increase in the dependence on mobile devices in everyday life, there is a growing concern related to privacy and security issues in the Gulf countries; therefore, it is imperative that security threats should be analyzed in detail. Mobile devices store enormous amounts of personal and financial information, unfortunately without any security. In order to secure mobile devices against different threats, biometrics has been applied and shown to be effective. However, biometric mobile applications are also vulnerable to several types of attacks that can decrease their security. Biometric information itself is considered sensitive data; for example, fingerprints can leave traces in touched objects and facial images can be captured everywhere or accessed by the attacker if the facial image is stored in the mobile device (lost or stolen. Hence, an attacker can easily forge the identity of a legitimate user and access data on a device. In this paper, the effects of a trace attack on the sensitivity of biometric mobile applications are investigated in terms of security and user privacy. Experimental results carried out on facial and fingerprint mobile authentication applications using different databases have shown that these mobile applications are vulnerable to the proposed attack, which poses a serious threat to the overall system security and user privacy.

  5. Trace element distribution in the rat cerebellum

    International Nuclear Information System (INIS)

    Kwiatek, W.M.; Long, G.J.; Pounds, J.G.; Reuhl, K.R.; Hanson, A.L.; Jones, K.W.

    1989-10-01

    Spatial distributions and concentrations of trace elements (TE) in the brain are important because TE perform catalytic structural functions in enzymes which regulate brain function and development. We have investigated the distributions of TE in rat cerebellum. Structures were sectioned and analyzed by the Synchrotron Radiation Induced X-ray Emission (SRIXE) method using the NSLS X-26 white-light microprobe facility. Advantages important for TE analysis of biological specimens with x-ray microscopy include short time of measurement, high brightness and flux, good spatial resolution, multielemental detection, good sensitivity, and non-destructive irradiation. Trace elements were measured in thin rat brain sections of 20-micrometers thickness. The analyses were performed on sample volumes as small as 0.2 nl with Minimum Detectable Limits (MDL) of 50 ppb wet weight for Fe, 100 ppb wet weight for Cu, and Zn, and 1 ppM wet weight for Pb. The distribution of TE in the molecular cell layer, granule cell layer and fiber tract of rat cerebella was investigated. Both point analyses and two-dimensional semi-quantitative mapping of the TE distribution in a section were used

  6. Enhanced UHF RFID tags for drug tracing.

    Science.gov (United States)

    Catarinucci, Luca; Colella, Riccardo; De Blasi, Mario; Patrono, Luigi; Tarricone, Luciano

    2012-12-01

    Radio Frequency Identification (RFID) technology is playing a crucial role for item-level tracing systems in healthcare scenarios. The pharmaceutical supply chain is a fascinating application context, where RFID can guarantee transparency in the drug flow, supporting both suppliers and consumers against the growing counterfeiting problem. In such a context, the choice of the most adequate RFID tag, in terms of shape, frequency, size and reading range, is crucial. The potential presence of items containing materials hostile to the electromagnetic propagation exasperates the problem. In addition, the peculiarities of the different RFID-based checkpoints make even more stringent the requirements for the tag. In this work, the performance of several commercial UHF RFID tags in each step of the pharmaceutical supply chain has been evaluated, confirming the expected criticality. On such basis, a guideline for the electromagnetic design of new high-performance tags capable to overcome such criticalities has been defined. Finally, driven by such guidelines, a new enhanced tag has been designed, realized and tested. Due to patent pending issues, the antenna shape is not shown. Nevertheless, the optimal obtained results do not lose their validity. Indeed, on the one hand they demonstrate that high performance item level tracing systems can actually be implemented also in critical operating conditions. On the other hand, they encourage the tag designer to follow the identified guidelines so to realize enhanced UHF tags.

  7. Electrostatic sampling of trace DNA from clothing.

    Science.gov (United States)

    Zieger, Martin; Defaux, Priscille Merciani; Utz, Silvia

    2016-05-01

    During acts of physical aggression, offenders frequently come into contact with clothes of the victim, thereby leaving traces of DNA-bearing biological material on the garments. Since tape-lifting and swabbing, the currently established methods for non-destructive trace DNA sampling from clothing, both have their shortcomings in collection efficiency and handling, we thought about a new collection method for these challenging samples. Testing two readily available electrostatic devices for their potential to sample biological material from garments made of different fabrics, we found one of them, the electrostatic dust print lifter (DPL), to perform comparable to well-established sampling with wet cotton swabs. In simulated aggression scenarios, we had the same success rate for the establishment of single aggressor profiles, suitable for database submission, with both the DPL and wet swabbing. However, we lost a substantial amount of information with electrostatic sampling, since almost no mixed aggressor-victim profiles suitable for database entry could be established, compared to conventional swabbing. This study serves as a proof of principle for electrostatic DNA sampling from items of clothing. The technique still requires optimization before it might be used in real casework. But we are confident that in the future it could be an efficient and convenient contribution to the toolbox of forensic practitioners.

  8. Defining utility trace substance emissions and risks

    International Nuclear Information System (INIS)

    Torrens, I.M.

    1993-01-01

    An update is presented on the activities of EPRI and other organizations, including DOE, aimed at improving the quality of available information on utility trace element emissions, control technologies and risks. Because of these efforts, the state of knowledge is advancing rapidly. The 1990 Clean Air Act Amendments aim to reduce emissions of 189 substances that they designate as hazardous air pollutants - commonly called air toxics. The more neutral term open-quotes trace substancesclose quotes is used in this paper, since most are emitted in extremely low concentrations from utility stacks. The degree of toxicity or hazard at these concentrations is subject to considerable uncertainty, and clarifying this is one of the objectives of the work in progress. The most clear and urgent need emanating from the CAAA has been to obtain reliable information on which of the substances on the CAAA list are emitted from different types of power plants - in what amounts, what risks they pose, how much is removed by today's pollution control equipment. EPRI is addressing the issue on several fronts, e.g.; developing a data base and tools that will enable utilities to estimate emissions levels from their power facilities, given the types of fuels burned and plant characteristics; developing a better understanding of how emissions are transported and transformed before they encounter humans and ecological systems; and assessing the risk to public health and the environment posed by utility releases of these substances

  9. Stabilisation de la formule des traces tordue

    CERN Document Server

    Moeglin, Colette

    2016-01-01

    Ce travail en deux volumes donne la preuve de la stabilisation de la formule des trace tordue. Stabiliser la formule des traces tordue est la méthode la plus puissante connue actuellement pour comprendre l'action naturelle du groupe des points adéliques d'un groupe réductif, tordue par un automorphisme, sur les formes automorphes de carré intégrable de ce groupe. Cette compréhension se fait en réduisant le problème, suivant les idées de Langlands, à des groupes plus petits munis d'un certain nombre de données auxiliaires; c'est ce que l'on appelle les données endoscopiques. L'analogue non tordu a été résolu par J. Arthur et dans ce livre on suit la stratégie de celui-ci. Publier ce travail sous forme de livre permet de le rendre le plus complet possible. Les auteurs ont repris la théorie de l'endoscopie tordue développée par R. Kottwitz et D. Shelstad et par J.-P. Labesse. Ils donnent tous les arguments des démonstrations même si nombre d'entre eux se trouvent déjà dans les travaux d'Ar...

  10. Standardization of C-14 by tracing method

    Energy Technology Data Exchange (ETDEWEB)

    Koskinas, Marina F.; Kuznetsova, Maria; Yamazaki, Ione; Brancaccio, Franco; Dias, Mauro S., E-mail: koskinas@ipen.br, E-mail: marysmith@usp.br, E-mail: yamazaki@ipen.br, E-mail: fbrancac@ipen.br, E-mail: msdias@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The standardization of a {sup 14}C radioactive solution by means of the efficiency tracing technique is described. The {sup 14}C is a beta pure emitter with endpoint energy of 156 keV decaying to the ground state of {sup 14}N. The activity measurement was performed in a 4πβ-γ coincidence system, measuring the pure beta emitter mixed with a beta gamma emitter, which provides the beta detection efficiency. The radionuclide {sup 60}Co, which decays by beta particle followed by two gamma rays, was used as tracer and the efficiency was obtained by selecting the 1173 keV plus 1332 keV total energy absorption peak at the gamma channel. Known aliquots of the tracer, previously standardized by 4πβ (PC)-γ coincidence, were mixed with known aliquots of {sup 14}C. The sources of {sup 14}C + {sup 60}Co were prepared by dropping known aliquots from each radioactive solution. The events were registered by a Software Coincidence System (SCS). The activity of the solution was determined by using the extrapolation technique, changing the beta efficiency by pulse height discrimination. In order to determine the final activity, a Monte Carlo simulation was used to calculate the extrapolation curve. All the uncertainties involved were treated rigorously, by means of the covariance analysis methodology. Measurements using a HIDEX, a commercial liquid scintillator system, were carried out and the results were compared with the tracing technique, showing a good agreement. (author)

  11. Determination of Trace Elements in Thai Cereal

    International Nuclear Information System (INIS)

    Permnamtip, Vorapot; Busamongkol, Arporn; Laoharojanaphand, Sirinart; Chaiyasith, Suwan

    2007-08-01

    Full text: Trace elements were analyzed in Thai cereal, e.g. rice and bean, by using neutron activation analysis (NAA). The selected cereals are major food items for Thai population. The data obtained from this work will be useful for nutrition and safety consumption of Thai cereal. Trace elements verified include Al, As, Br, Ca, Cd, Cl, Cr, Cu, Fe, I, K, Mg, Mn, Mo, Se, Sn, V and Zn. It was found that Al, As, Br, Cl, Cu, Fe, Mn, Zn, Ca, K and Mg are presented in the range of 2.2 to 35.7, 0.15 to 0.21, 0.44 to 13.5, 55.6 to 640.3, 16.3 to 16.5, 158.9 to 161.1, 12.2 to 55.7, 8.2 to 58.1 (g/g (ppm) , 0.02 to 0.28, 0.09 to 1.99 and 0.03 to 0.26 %, respectively. For Cd, Cr, I, Mo, Se, Sn and V were not found in sample because the concentrations were lower than detection limit. Precision and accuracy were determined by analyzing standard reference materials: NIST 1568a, NIST 8704, ACSP DORM-1, NIES No.9 and NMIJ 7302 to a

  12. Trace elements in termites by PIXE analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, T. E-mail: tsuyoshi@termite.kuwri.kyoto-u.ac.jp; Kagemori, N.; Kawai, S.; Sera, K.; Futatsugawa, S

    2002-04-01

    Trace elements in a Japanese subterranean xylophagous termite, Coptotermes formosanus Shiraki, were analyzed by the PIXE method. The total amount of the 14 predominant elements out of 27 detected in an intact termite was higher in a soldier termite (23 000 {mu}g/g) than in a worker termite (10 000 {mu}g/g). A block of wood (Pinus densiflora Sieb. et Zucc.) for termite feed had a much lower concentration (3600 {mu}g/g) compared with that in an intact termite. This probably relates the functional bio-condensation and/or bio-recycling of trace elements in C. formosanus. When a termite was separated into three anatomical parts, head, degutted body and gut, the worker gut contained the highest total amount of the 14 predominant measured elements (31 000 {mu}g/g). This might be correlated with the higher activity of food digestion and energy production in the worker gut. Moreover, the mandible of the soldier head, with an exoskeleton that is intensely hardened, showed a preferential distribution of Mn and Fe. These results suggest that the characteristic localization of elements will be closely related to the functional role of the individual anatomical part of C. formosanus.

  13. Method development for trace and ultratrace analysis

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Method development, that is, selection of a mode of chromatography and the right column and mobile-phase combination for trace and ultratrace analysis, requires several main considerations. The method should be useful for resolving various trace and ultratrace components present in the sample. If the nature of these components is known, the choice of method may be straightforward, that is, a selection can be made from the following modes of HPLC: (1) adsorption chromatography; (2) normal-phase chromatography; (3) reversed-phase chromatography; (4) ion-pair chromatography; (5) ion-exchange chromatography; (6) ion chromatography. Unfortunately, the nature of all of the components is frequently unknown. However, several intelligent judgments can be made on the nature of impurities. This chapter deals with some basic approaches to mobile-phase selection and optimization. More detailed information may be found in basic texts. Techniques for separation of high-molecular-weight compounds (macromolecules) and chiral compounds may be found elsewhere. Mainly compounds with molecular weight lower than 2,000 are discussed here. 123 refs

  14. Concentration of trace elements in marine organisms

    International Nuclear Information System (INIS)

    Ishii, Takaaki; Suzuki, Hamaji; Iimura, Mitsue; Koyanagi, Taku

    1976-01-01

    Information on the quality and quantity of stable trace elements in marine environments is frequently required to analyze the radioecological behavior of radionuclides released from nuclear facilities into the sea. In the present work, special attention was concentrated in determination of stable Mn, Fe, Co, Zn, Rb and Cs in marine organisms to estimate the concentration factors for these elements and corresponding radionuclides. Marine organisms (fishes, marine invertebrates and seaweeds) were collected at the seashore of Ibaragi prefecture and provided for chemical analysis after dry-ashing and wet-ashing. Atomic absorption spectrophotometry and neutron activation analysis were applied to determine the concentration of elements. The concentration of stable elements in fish muscle was independent on species of the fishes though slightly higher trends were observed in ''Usumebaru'', Sebastes nivosus for Cs, ''Ishimochi'', Nibea mitsukurii for Zn and Fe compared with other species. The concentration of Co, Zn and Fe in muscle of marine invertebrates was one order of magnitude higher than fish muscles especially in shellfishes for Co. Seaweeds showed peculiar species specificity for the concentration of stable trace elements and remarkable differences was observed between the species even among the same genus. (auth.)

  15. Trace elements in renal disease and hemodialysis

    International Nuclear Information System (INIS)

    Miura, Yoshinori; Nakai, Keiko; Suwabe, Akira; Sera, Koichiro

    2002-01-01

    A number of considerations suggest that trace element disturbances might occur in patients with renal disease and in hemodialysis (HD) patients. Using particle induced X-ray emission, we demonstrated the relations between serum concentration, urinary excretion of the trace elements and creatinine clearance (Ccr) in randomized 50 patients. To estimate the effects of HD, we also observed the changes of these elements in serum and dialysis fluids during HD. Urinary silicon excretion decreased, and serum silicon concentration increased as Ccr decreased, with significant correlation (r=0.702, p<0.001 and r=0.676, p<0.0001, respectively). We also observed the increase of serum silicon, and the decrease of silicon in dialysis fluids during HD. These results suggested that reduced renal function and also dialysis contributed to silicon accumulation. Although serum selenium decreased significantly according to Ccr decrease (r=0.452, p<0.01), we could detect no change in urinary selenium excretion and no transfer during HD. Serum bromine and urinary excretion of bromine did not correlate to Ccr. However we observed a bromine transfer from the serum to the dialysis fluid that contributed to the serum bromine decrease in HD patients

  16. RayTrace: A Simplified Ray Tracing Software for use in AutoCad

    DEFF Research Database (Denmark)

    Reimann, Gregers Peter; Tang, C.K.

    2005-01-01

    A design aid tool for testing and development of daylighting systems was developed. A simplified ray tracing software was programmed in Lisp for AutoCad. Only fully specularly reflective, fully transparent and fully absorbant surfaces can be defined in the software. The software is therefore best...

  17. Generation and validation of traces between requirements and architecture based on formal trace semantics

    NARCIS (Netherlands)

    Göknil, Arda; Ivanov, Ivan; van den Berg, Klaas

    The size and complexity of software systems make integration of the new/modified requirements to the software system costly and time consuming. The impact of requirements changes on other requirements, design elements and source code should be traced to determine parts of the software to be changed.

  18. How Well Do Neodymium Isotopes Trace AMOC Mixing? A Test in the Southwest Atlantic

    Science.gov (United States)

    Wu, Y.; Goldstein, S. L.; Pena, L.; Hartman, A. E.; Rijkenberg, M. J. A.; De Baar, H. J. W.

    2014-12-01

    Neodymium (Nd) isotope ratios are used to trace past AMOC circulation, based on observations that seawater Nd isotope ratios effectively "fingerprint" water masses, and that over long water mass transport distances in deep seawater they reflect values expected from water mass mixing. Over the past several years, studies have increasingly focused on the potential of external addition of Nd along water mass transport paths (for example through "boundary exchange" with particulates or addition from groundwaters), thus challenging the idea that Nd isotopes behave "quasi-conservatively" in the oceans. The SW Atlantic, with the major water masses involved in the AMOC (southward flowing NADW, northward flowing AAIW and AABW), is arguably the best place on Earth to evaluate how well Nd isotopes trace water mass mixing, in order to clarify its value for following the AMOC through time. We will report Nd isotope ratios of seawater collected on the SW Atlantic meridional transect of the NIOZ West Atlantic GEOTRACES Cruise Leg 3 (RRS James Cook 057), which sampled seawater profiles and the sediment surface at 18 stations between 0-50°S. Most stations are sampled in the open ocean, providing a test of whether Nd isotopes show quasi-conservative mixing systematics away from continental margins. The cruise section also provides several opportunities to test the potential effects of external Nd input. For example, it transects the continental shelf in the far south, the Rio Grande Rise, volcanic seamounts, and the major geological age boundaries of South America. It also crosses the major Southern Hemisphere wind zones, allowing us to test the impacts of aeolian input, and inputs from major rivers (Parana-Paraguay, Sao Francisco, Amazon). All of these features have the potential to modify the seawater Nd isotope ratios, allowing us to determine if they add significant external Nd.

  19. The local mass density

    Science.gov (United States)

    Veeder, G. J.

    1974-01-01

    An improved mass-luminosity relation for faint main-sequence stars derived from recently revised masses for some faint double stars is presented. The total local mass density is increased to nearly 0.2 solar masses per cu pc. This estimate is as large as the mass density required by Oort's (1965) dynamical analysis of stellar motions perpendicular to the galactic plane if the mass is concentrated in a narrow layer.

  20. TRACING SAGITTARIUS STRUCTURE WITH SDSS AND SEGUE IMAGING AND SPECTROSCOPY

    International Nuclear Information System (INIS)

    Yanny, Brian; Newberg, Heidi Jo; Johnson, Jennifer A.; Lee, Young Sun; Beers, Timothy C.; Bizyaev, Dmitry; Brewington, Howard; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Dan; Pan, Kaike; Simmons, Audrey; Snedden, Stephanie; Fiorentin, Paola Re; Harding, Paul

    2009-01-01

    We show that the Sagittarius dwarf tidal stream can be traced with very red K/M-giant stars, selected from Sloan Digital Sky Survey (SDSS) photometry. A subset of these stars are spectroscopically confirmed with SEGUE and SDSS spectra, and the distance scale of 2MASS and SDSS M giants is calibrated to the RR Lyrae distance scale. The absolute magnitude of the K/M-giant stars at the tip of the giant branch is M g 0 =-1.0. The line-of-sight velocities of the M giant and blue horizontal-branch (BHB) stars that are spatially coincident with the Sgr dwarf tidal stream are consistent with those of previous authors, reinforcing the need for new models that can explain all of the Sgr tidal debris stream observations. We estimate stellar densities along the tidal tails that can be used to help constrain future models. The K/M giant, BHB, and F-turnoff stars in the lower surface brightness tidal stream that is adjacent to the main leading Sgr dwarf tidal tail have velocities and metallicities that are similar to those of the stars in the leading tidal tail. The ratio of K/M giants to BHBs and BHBs to F-turnoff stars are also similar for both branches of the leading tidal tail. We show that there is an additional low-metallicity tidal stream near the Sgr trailing tidal tail.