Isotopic fingerprints of sulfur metabolisms: using the minor isotopes to distinguish ... Here we report sulfur multiple-isotope measurements of the hydrogen sulfide ...

A method is described that allows measuring the isotopic composition of small uranium oxide particles (less than 1?m in diameter) for nuclear safeguards purposes. In support to the development of reliable tools for the identification of uranium and plutonium signatures in trace amounts of nuclear materials, improvements in scanning electron microscopy (SEM) and thermal ...

The cw laser RIMS approach has been demonstrated to accurately measure large Lu isotope ratios and detect small levels of minor isotopes even in the presence of isobaric interferences. The same approach can also be used to obtain high resolution optical spectra of rare isotopes. For elements ...

Abstract: This data set consists of Dutton et al. 2002 Eocene Bivalve Isotope and Minor Element Data. Splits of bulk powdered samples of Cucullaea sp. ...

bonites, perovskites and anorthites occur in the CAI as minor minerals. The detailed petrographic texture, chemical compositions, and isotopic distributions ...

... 4. TITLE AND SUBTITLE Identifying Minor Planets in UCAC Data and Deriving Accurate OC 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. ...

... Accession Number : ADA455924. Title : Identifying Minor Planets in UCAC Data and Deriving Accurate OC. Corporate Author ...

EDXRF Minor and trace elements. " ICP-AES, ICP-MS Minor and trace elements. " INAA Minor and trace elements. " MC-ICPMS Trace elements, isotopes ...

In this work we present an accurate parameterization of the antineutrino flux produced by the isotopes 235U, 239Pu, and 241Pu in nuclear reactors. We determine the coefficients of this parameterization, as well as their covariance matrix, by performing a fit to spectra inferred from experimentally measured beta spectra. Subsequently we show that flux shape ...

... However, if the beliefs of minorities that they will be subject to harassment and will not have the same opportunities for advancement are accurate ...

Accurate minority carrier recombination rate measurements by new capacitance transient method of Ti,

The minor isotopes of uranium (U-233, U-234, U-236) are increasingly useful for tracing a variety of processes: movement of anthropogenic nuclides in the environment (ref 1), sources of uranium ores (ref 2), and nuclear material attribution (ref 3). We report on improved accuracy for U-234/238 and U-236/238 by supplementing total evaporation protocol ...

Inductively coupled plasma mass spectrometry combined with stable isotope dilution is applied to accurate isotopic analysis of human fecal matter for /sup 54/Fe and /sup 58/Fe. Argon plasma generated interferences are of minor concern. The interference from /sup 54/Cr can be corrected instrumentally, whereas /sup ...

S>Plutonium was determined by counting the alpha sources prepared by evaporating small aliquots of solutions prepared from binary alloys of Pu with Pb, Sn or Bi and of tertiary alloys of Pu and Bi with Pb or Sn. A Pu standard is used, of similar isotopic composition to the alloyed Pu. The results are accurate to plus or minus 2% ( SIGMA ...

Element Data. Splits of bulk powdered samples of Cucullaea sp. bivalve from the ... minor element proxies for Eocene climate of Seymour Island, Antarctica. ...

this deficiency by using paired oxygen isotope and minor element (magnesium/ calcium) ratios of planktonic foraminifera from a tropical Pacific ...

A study of the behavior of the minor uranium isotopes in enrichment cascades indicates that the measurement of their concetrations in cascade feed and withdrawal streams can be used to confirm or deny material accountability results in safeguarding an enr...

Part V is the final chapter of the completion report for this study. The results of the calculations made to determine the behavior of the minor uranium isotopes ( exp 234 U and exp 236 U) in separation cascades and the results of the two plant tests made...

Part V is the final chapter of the completion report for this study. The results of the calculations made to determine the behavior of the minor uranium isotopes (U-234 and U-236) in separation cascades and the results of the two plant tests made to subst...

... magnesium, calcium, potassium, chloride and some minor elements in the . .... Geochemical studies, the natural abundance of nitrogen isotopes in soil ...

... more accurate) been encouraged to engage in, a career studying bryophytes, ... minorities climbed, albeit sometimes successfully (e.g., N. Pringsheim), ... ...

In this work we present an accurate parameterization of the antineutrino flux produced by the isotopes {sup 235}U, {sup 239}Pu, and {sup 241}Pu in nuclear reactors. We determine the coefficients of this parameterization, as well as their covariance matrix, by performing a fit to spectra inferred from experimentally measured beta spectra. Subsequently we ...

Liver tumours frequently present at a late stage and only a minority of patients are likely to benefit from resection or transplantation. Inoperable tumours carry a grave prognosis. External beam irradiation of the liver is dose-limited by the radiosensitivity of hepatocytes, particularly in the presence of cirrhosis, but internal radiation using ...

Two computer programs have been written to provide information on the buildup of minor uranium isotopes in the nuclear fuel cycle. The Minor Uranium Isotope Cycle Program, MUICYCL, tracks fuel through a multiyear campaign cycle of enrichment, reactor burnup, reprocessing, enrichment, etc. MUICYCL facilities include ...

The isotopic method of determining absolute age is the most accurate and .... Another method of relative age dating involves the relative abundance of ...

Some of these compounds have isotopic signatures that are characteristic of ... can be definitely detected and a very accurate abundance determined. ...

This seminal paper contains the results of the mass spectrographic determination of the relative abundances of the uranium isotopes, U�238, U�235, and U�234. No other isotopes of uranium were observed. The half�lives of the isotopes were also reported. These were the most accurate measurements of ...

The accurate determination of isotope abundances by any method requires that the measuring systems be calibrated using well characterized isotope reference materials. The National Bureau of Standards (NBS) and the Central Bureau for Nuclear Measurements (...

Isotope dilution Ar analyses are reported for all samples originally analysed by neutron activation. The methods are in agreement but the more precise and accurate isotope dilution analyses are preferred.

Two advanced prototype mass spectrometers for the accurate analysis of mixtures of the hydrogen isotopes were evaluated. One, a VG-Isotopes GAZAB, was developed for the Mass Spectrometer Technical Group, a group representing ten DOE contractors. The other...

Despite their great importance in low-temperaturegeochemistry, self-diffusion coefficients of noble gas isotopes in liquidwater (D) have been measured only for the major isotopes of helium, neon,krypton and xenon. Data on the self-diffusion coefficients of minor noblegas isotopes are essentially non-existent and so ...

Atmospheric argon measured on a dynamically operated mass spectrometer with an ion source magnet, indicated systematically larger 40Ar/36Ar ratios compared to the generally accepted value of Nier [Nier A.O., 1950. A redetermination of the relative abundances of the isotopes of carbon, nitrogen, oxygen, argon, and potassium. Phys. Rev. 77, 789 793], 295.5 � 0.5, which has ...

The mass spectrometric determination of minor abundant isotopes, (sup 234)U and (sup 236)U in naturally occurring uranium materials requires instruments of high abundance sensitivity and the use of highly sensitive detection systems. In this study the the...

Measurement of passive gamma rays emitted by the decay of radioactive isotopes is a widely used and fundamental technique to verify and determine characteristics of nuclear materials. Several initiatives are currently under way to investigate the use of advanced nondestructive assay methods for application to independently measure the fissile material and plutonium content in ...

We recently described a Bayesian framework for stable isotope mixing models and provided a software tool, MixSIR, for conducting such analyses (Ecol. Lett., 2008; 11:470). Jackson et al. (Ecol. Lett., 2009; 12:E1) criticized the performance of our software based on tests using simulated data. However, their simulation data were flawed, rendering claims of erroneous behaviour ...

A method for the precise and accurate determination of the tellurium (Te) isotope compositions of calcium-aluminum-rich inclusions (CAIs) has been developed. The technique utilizes multiple-collector inductively coupled plasma-mass spectrometry (MC-ICPMS) with either Faraday detectors or a dual ion-counting system. The external reproducibility (2?) for ...

Here a new analytical methodology is described for measuring the isotopic composition of boron in foraminifera using multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). This new approach is fast (� 10 samples analysed in duplicate per analytical session) and accurate (to better than 0.25� at 95% confidence) with acceptable sample ...

Cadmium Zinc Telluride (CZT) detectors are the highest resolution room-temperature gamma ray detectors available for isotopic analysis. As with germanium detectors, accurate isotopic analysis using the spectra requires peak deconvolution. The CZT peak shapes are asymmetric, with a long low energy tail. The asymmetry is a result of the ...

sulfur, carbonate, carbonaceous material, forty major, minor, and trace elements, antimony, barium, tellurium, sulfide sulfur isotopes and selected samples for carbonate carbon...

A new approach to stable-isotope ratio analysis based on atomic hyperfine structure is demonstrated. This laser spectroscopic scheme is virtually interference-free. A minor constituent in a complex matrix can be selectively analyzed without extensive samp...

An indirect method for estimating the inventory of a uranium enrichment cascade which presumably can be performed by the International Atomic Energy Agency within the Non-Proliferation Treaty limitations on its safeguards activities was devised and tested...

The High-Flux Isotope Reactor (HFIR) has outstanding neutronics characteristics for materials irradiation, but some relatively minor aspects of its mechanical design severely limited its usefulness for that purpose. In particular, though the flux trap reg...

Chemical diffusivities for nonalkali major, minor, and selected trace elements have been measured at

... techniques were used to enhance the abundance of minor components. Here, even 'in the less sensitive broadband mode, the isotopic peaks of W ...

There is increased interest in accurately assessing the total dietary intake of vitamins from all sources, including foods and dietary supplements. Isotope dilution can be a definitive analytical method for very accurate concentration determinations. Thus, a liquid chromatographic (LC) isotope dilut...

An online method using continuous flow isotope ratio mass spectrometry (CF-IRMS) interfaced with a Gasbench II device was established to analyze carbon and oxygen isotopic compositions and to estimate the content of minor amounts of carbonate in silicate rocks. The mixtures of standard materials and high-purity quartz are firstly used ...

In fuel cycles with recycled actinide, core characteristics are largely influenced by minor actinide (MA: Np, Am). Accurate nuclear data of MA such as fission cross section are required to estimate the effect of MA with high accuracy. In this study, fast ...

... Title : (M-CAT) Minor Caliber Weapons Trainer MK-19, 40mm Machine Gun. ... M-CAT accurately simulates both trajectory and lead for correct scoring. ...

We demonstrate a simple method that can be used to detect minor isotope lines in a saturated absorption spectrum by the absorption filtering of major isotope lines. We investigate this method for use in the spectroscopy of the 1S0-1P1 transition in Yb at 399 nm by controlling the density of Yb atoms by varying the discharge current of ...

We have proposed a novel scheme for isotopic analysis of noble gases. Our calculations indicate that this new technique should be capable of measuring isotope ratios below 10 sup -12 in samples containing as few as 10 sup 5 atoms of the minor isotope. Thi...

The p-process of stellar nucleosynthesis produces the stable neutron-deficient nuclides heavier than the iron peak elements. An accurate determination of the isotopic composition of tantalum is required to enable p-process nucleosynthetic calculations to be evaluated in terms of an accurate isotope abundance for ...

We present a new method for analyzing the delta(13)C isotopic composition of several oxygenated volatile organic compounds (OVOCs) from direct sources and ambient atmospheric samples. Guided by the requirements for analysis of trace components in air, a gas chromatograph isotope ratio mass spectrometer (GC-IRMS) system was developed with the goal of ...

An accurate analysis of aluminum alloys is required for quality control and characterization purposes. The two analytical techniques atomic absorption spectroscopy and inductively coupled plasma atomic emission spectroscopy are used for the the determinat...

... with an emphasis on underrepresented minority groups," said Dr. Nabil Ibrahim, ... NASA Opens Sky for Students | More Accurate Weather, Space Research | ...

Uranium isotope ratios can provide source information for tracking uranium contamination in a variety of fields, ranging from occupational bioassay to monitoring aftereffects of nuclear accidents. We describe the development of isotope selective laser ionization spectrometry for ultratrace measurement of the minor ...

A rapid gas chromatography-tandem mass spectrometry (GC-MS/MS) analytical method was developed for the simultaneous analysis of 7 estrogenic hormones (17?-estradiol, 17?-estradiol, estrone, mestranol, 17?-ethynylestradiol, levonorgestrel, estriol) and 5 androgenic hormones (testosterone, androsterone, etiocholanolone, dihydrotestosterone, androstenedione) in aqueous matrices. This method is unique ...

Diffusion models predict that peak metamorphic temperatures are best recorded by the oxygen isotope fractionation between minerals in a bi-mineralic rock in which a refractory accessory mineral with slow oxygen diffusion rate is modally minor to a mineral with a faster diffusion rate. This premise is demonstrated for high-grade metamorphism on the island ...

Accurate determination of chlorine concentrations in terrestrial rocks is of importance for the interpretation of terrestrial in-situ cosmogenic 36Cl. Neutron capture by 35Cl, together with production from Ca and K, is one of the three major production pathways of 36Cl in rocks. Here, we present an inter-comparison of chlorine determinations by two procedures. The first ...

Atomic masses and isotopic abundances are independent and complementary properties for discriminating among ion compositions. The number of possible ion compositions is greatly reduced by accurately measuring exact masses of monoisotopic ions and the relative isotopic abundances...

An isotope dilution method using sodium 35-sulfate for the determination of inorganic sulfate in urine is described. This method, based on a fractional precipitation of sulfate as BaSO4, has proven to be as accurate as currently used micro techniques and ...

To permit more accurate calculations of tritium permeation for design purposes, theoretical expressions for quasiunidirectional ordinary diffusion of hydrogen isotopes through nonisothermal plane, cylindrical shell, and spherical shell barriers are presen...

The report discusses the method used in determining maximum permissible concentration of radioactive isotopes as produced by Army nuclear reactors. Accurate current MPC's for use at the SM-1 Nuclear Power Plant at Fort Belvoir, Va., are derived. Final MPC...

Photodisintegration of Lithium Isotopes R.E. Pywell, W.A. Wurtz University of Saskatchewan B. Norum-Body Photodisintegration Accurate theoretical calculations are now possible e.g. Lorentz Integral Transform technique (e

A theoretical study of the mass spectrometric analysis of mixtures of the hydrogen and helium isotopes shows that mass discrimination and low ion intensity in ion sources are the principal factors that limit accuracy. A virtual-image ion source with short...

... the unique isotopic signature of the ore body from which the lead was mined. ... an accurate record of the effects of human-induced lead pollution on the .... Maring, H., Niemeyer, S. (1993) Anthropogenic Pb in Antarctic sea water. ...

A rapid and accurate CI-MS method has been developed for the isotopic analysis of enriched boron. This method involves the formation of volatile methyl borate from boric acid with direct introduction of the methyl borate into the source of a quadrupole ma...

The Graphite Isotope Ratio Method (GIRM) is a technique used to estimate the total plutonium production in a graphite-moderated reactor. The cumulative plutonium production in that reactor can be accurately determined by measuring neutron irradiation indu...

Laboratory evaporation residues are used to test the proposition that combining the measured bulk and isotopic composition of the residues allows one to accurately determine the composition of the precursor.

The purpose of the study is to evaluate the availability and accuracy of existing methods for predicting fission product, cladding-mutant, and actinide concentrations and isotopic ratios in discharged reactor fuel elements after various irradiation and co...

The Bayes a priori distribution estimate, using the equal-indeterminancy principle, is proposed for processing isotope thickness measurement information for small deviations from the base value. The Bayes estimate is more accurate than the maximum-probability estimate.

Application of the spectrometric isotope dilution technique for the accurate determination of parts per million range of uranium in rock samples is described. The various aspects of the method like sample dissolution, ion exchange separation, mass spectro...

Two advanced mass spectrometers for the accurate analysis of mixtures of the hydrogen isotopes were evaluated by Du Pont personnel at the Savannah River Laboratory. One is a large double-focusing instrument with a resolution of 2000 at mass 4 and an abund...

The new mass spectrometric determination of the atomic weight of thallium has been completed. A high precision assay technique was developed so that accurately known quantities of the 203Tl and 205Tl separated isotopes could be mixed to produce standards ...

New and very accurate data of isotope shifts and relative isotope shifts in /sup 234/U, /sup 236/U, /sup 238/U are presented. The invariance of the relative isotope shift, for the transitions we have investigated, supports the hypothesis that the so called specific mass effect is negligible in uranium. (AIP)

A cryogenic gas chromatograph is described that was constructed for dedicated analysis of permanent gas and hydrogen isotopic impurities in tritium and deuterium-tritium mixtures. The operating characteristics of this instrument and some results are presented in order to introduce gas chromatography as an analytical technique for potential application to CTR technology ...

The generation of accurate scaling of mutiplicity distributions is presented. The distributions of (pi)(sup -) mesons (negative particles) and (pi)(sup +) mesons in different nucleon-nucleon interactions (PP, NP and NN) are described by the same universal...

... Reactions: Accurate Quantum Calculations for ... Corporate Author : CHEMICAL DYNAMICS CORP ... Descriptors : *Quantum chemistry, *Computations ...

... and then analyzed for δ13C and δ15N values. Gravimetric analysis is an inexpensive and accurate method that is ... ...