Sample records for kev u-235 450-500

  1. IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets

    DOE PAGES

    Capote, R.; Trkov, A.; Sin, M.; ...

    2018-02-01

    Evaluations of nuclear reaction data for the major uranium isotopes 238U and 235U were performed within the scope of the CIELO Project on the initiative of the OECD/NEA Data Bank under Working Party on Evaluation Co-operation (WPEC) Subgroup 40 coordinated by the IAEA Nuclear Data Section. Both the mean values and covariances are evaluated from 10 -5 eV up to 30 MeV. The resonance parameters of 238U and 235U were re-evaluated with the addition of newly available data to the existing experimental database. The evaluations in the fast neutron range are based on nuclear model calculations with the code EMPIRE–3.2more » Malta above the resonance range up to 30 MeV. 235U(n,f), 238U(n,f), and 238U(n,γ) cross sections and 235U(n th,f) prompt fission neutron spectrum (PFNS) were evaluated within the Neutron Standards project and are representative of the experimental state-of-the-art measurements. The Standards cross sections were matched in model calculations as closely as possible to guarantee a good predictive power for cross sections of competing neutron scattering channels. 235U(n,γ) cross section includes fluctuations observed in recent experiments. 235U(n,f) PFNS for incident neutron energies from 500 keV to 20 MeV were measured at Los Alamos Chi-Nu facility and re-evaluated using all available experimental data. While respecting the measured differential data, several compensating errors in previous evaluations were identified and removed so that the performance in integral benchmarks was restored or improved. Covariance matrices for 235U and 238U cross sections, angular distributions, spectra and neutron multiplicities were evaluated using the GANDR system that combines experimental data with model uncertainties. Unrecognized systematic uncertainties were considered in the uncertainty quantification for fission and capture cross sections above the thermal range, and for neutron multiplicities. Evaluated files were extensively benchmarked to ensure good

  2. IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets

    NASA Astrophysics Data System (ADS)

    Capote, R.; Trkov, A.; Sin, M.; Pigni, M. T.; Pronyaev, V. G.; Balibrea, J.; Bernard, D.; Cano-Ott, D.; Danon, Y.; Daskalakis, A.; Goričanec, T.; Herman, M. W.; Kiedrowski, B.; Kopecky, S.; Mendoza, E.; Neudecker, D.; Leal, L.; Noguere, G.; Schillebeeckx, P.; Sirakov, I.; Soukhovitskii, E. S.; Stetcu, I.; Talou, P.

    2018-02-01

    Evaluations of nuclear reaction data for the major uranium isotopes 238U and 235U were performed within the scope of the CIELO Project on the initiative of the OECD/NEA Data Bank under Working Party on Evaluation Co-operation (WPEC) Subgroup 40 coordinated by the IAEA Nuclear Data Section. Both the mean values and covariances are evaluated from 10-5 eV up to 30 MeV. The resonance parameters of 238U and 235U were re-evaluated with the addition of newly available data to the existing experimental database. The evaluations in the fast neutron range are based on nuclear model calculations with the code EMPIRE-3.2 Malta above the resonance range up to 30 MeV. 235U(n,f), 238U(n,f), and 238U(n,γ) cross sections and 235U(nth,f) prompt fission neutron spectrum (PFNS) were evaluated within the Neutron Standards project and are representative of the experimental state-of-the-art measurements. The Standards cross sections were matched in model calculations as closely as possible to guarantee a good predictive power for cross sections of competing neutron scattering channels. 235U(n,γ) cross section includes fluctuations observed in recent experiments. 235U(n,f) PFNS for incident neutron energies from 500 keV to 20 MeV were measured at Los Alamos Chi-Nu facility and re-evaluated using all available experimental data. While respecting the measured differential data, several compensating errors in previous evaluations were identified and removed so that the performance in integral benchmarks was restored or improved. Covariance matrices for 235U and 238U cross sections, angular distributions, spectra and neutron multiplicities were evaluated using the GANDR system that combines experimental data with model uncertainties. Unrecognized systematic uncertainties were considered in the uncertainty quantification for fission and capture cross sections above the thermal range, and for neutron multiplicities. Evaluated files were extensively benchmarked to ensure good performance in

  3. IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Capote, R.; Trkov, A.; Sin, M.

    Evaluations of nuclear reaction data for the major uranium isotopes 238U and 235U were performed within the scope of the CIELO Project on the initiative of the OECD/NEA Data Bank under Working Party on Evaluation Co-operation (WPEC) Subgroup 40 coordinated by the IAEA Nuclear Data Section. Both the mean values and covariances are evaluated from 10 -5 eV up to 30 MeV. The resonance parameters of 238U and 235U were re-evaluated with the addition of newly available data to the existing experimental database. The evaluations in the fast neutron range are based on nuclear model calculations with the code EMPIRE–3.2more » Malta above the resonance range up to 30 MeV. 235U(n,f), 238U(n,f), and 238U(n,γ) cross sections and 235U(n th,f) prompt fission neutron spectrum (PFNS) were evaluated within the Neutron Standards project and are representative of the experimental state-of-the-art measurements. The Standards cross sections were matched in model calculations as closely as possible to guarantee a good predictive power for cross sections of competing neutron scattering channels. 235U(n,γ) cross section includes fluctuations observed in recent experiments. 235U(n,f) PFNS for incident neutron energies from 500 keV to 20 MeV were measured at Los Alamos Chi-Nu facility and re-evaluated using all available experimental data. While respecting the measured differential data, several compensating errors in previous evaluations were identified and removed so that the performance in integral benchmarks was restored or improved. Covariance matrices for 235U and 238U cross sections, angular distributions, spectra and neutron multiplicities were evaluated using the GANDR system that combines experimental data with model uncertainties. Unrecognized systematic uncertainties were considered in the uncertainty quantification for fission and capture cross sections above the thermal range, and for neutron multiplicities. Evaluated files were extensively benchmarked to ensure good

  4. Nuclear Resonance Fluorescence of U-235

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Warren, Glen A.; Caggiano, Joseph A.; Hensley, Walter K.

    Nuclear resonance fluorescence is a physical process that provides an isotopic-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample which is exposed to photons in the MeV energy range. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials. One isotope of significant interest is 235U. Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct measurements to search for a nuclear resonance fluorescence response of 235U below 3 MeV using a 200 g samplemore » of highly enriched uranium. Nine 235U resonances between 1650 and 2010 keV were identified in the preliminary analysis. Analysis of the measurement data to determine the integrated cross sections of the resonances is in progress.« less

  5. Use of integral experiments for the assessment of a new 235U IRSN-CEA evaluation

    NASA Astrophysics Data System (ADS)

    Ichou, Raphaëlle; Leclaire, Nicolas; Leal, Luiz; Haeck, Wim; Morillon, Benjamin; Romain, Pascal; Duarte, Helder

    2017-09-01

    The Working Party on International Nuclear Data Evaluation Co-operation (WPEC) subgroup 29 (SG 29) was established to investigate an issue with the 235U capture cross-section in the energy range from 0.1 to 2.25 keV, due to a possible overestimation of 10% or more. To improve the 235U capture crosssection, a new 235U evaluation has been proposed by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and the CEA, mainly based on new time-of-flight 235U capture cross-section measurements and recent fission cross-section measurements performed at the n_TOF facility from CERN. IRSN and CEA Cadarache were in charge of the thermal to 2.25 keV energy range, whereas the CEA DIF was responsible of the high energy region. Integral experiments showing a strong 235U sensitivity are used to assess the new evaluation, using Monte-Carlo methods. The keff calculations were performed with the 5.D.1 beta version of the MORET 5 code, using the JEFF-3.2 library and the new 235U evaluation, as well as the JEFF-3.3T1 library in which the new 235U has been included. The benchmark selection allowed highlighting a significant improvement on keff due to the new 235U evaluation. The results of this data testing are presented here.

  6. 238U/235U determinations of some commonly used reference materials and U-bearing accessory minerals (Invited)

    NASA Astrophysics Data System (ADS)

    Condon, D.; Noble, S.; McLean, N.; Bowring, S. A.

    2009-12-01

    We have determined 238U/235U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials in addition to several U-bearing accessory phases (zircon and monazite) by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 233U-236U double spike to accurately correct for mass fractionation. The 238U/235U values for the natural uranium reference materials differ, by up to 0.1%, from the widely used ‘consensus’ value (137.88) with all having 238U/235U values less than 137.88. Similarly, initial 238U/235U data from zircon and monazite yield 238U/235U values that are lower than the ‘consensus’ value. The data obtained from U-bearing minerals is used to assess how the uncertainty in the 238U/235U ratio contributes to the systematic discordance observed in 238U/206Pb and 235U/207Pb dates (Mattinson, 2000; Schoene et al., 2006) which has traditionally been wholly attributed to error in the U decay constants. The 238U/235U determinations made on the synthetic reference materials yield results that are considerably more precise and accurate than the certified values (0.02% vs. 0.1% for CRM U500). The calibration of isotopic tracers used for U-daughter geochronology that are partially based upon these reference materials, and the resultant age determinations, will benefit from increased accuracy and precision. Mattinson, J.M., 2000. Revising the “gold standard”—the uranium decay constants of Jaffey et al., 1971. Eos Trans. AGU, Spring Meet. Suppl., Abstract V61A-02. Schoene B., Crowley J.L., Condon D.C., Schmitz M.D., Bowring S.A., 2006, Reassessing the uranium decay constants for geochronology using ID-TIMS U-Pb data. Geochimica et Cosmochimica Acta 70: 426-445

  7. Fission-fragment total kinetic energy and mass yields for neutron-induced fission of 235U and 238U with En =200 keV - 30 MeV

    NASA Astrophysics Data System (ADS)

    Duke, D. L.; Tovesson, F.; Brys, T.; Geppert-Kleinrath, V.; Hambsch, F.-J.; Laptev, A.; Meharchand, R.; Manning, B.; Mayorov, D.; Meierbachtol, K.; Mosby, S.; Perdue, B.; Richman, D.; Shields, D.; Vidali, M.

    2017-09-01

    The average Total Kinetic Energy (TKE) release and fission-fragment yields in neutron-induced fission of 235U and 238U was measured using a Frisch-gridded ionization chamber. These observables are important nuclear data quantites that are relevant to applications and for informing the next generation of fission models. The measurements were performed a the Los Alamos Neutron Science Center and cover En = 200 keV - 30 MeV. The double-energy (2E) method was used to determine the fission-fragment yields and two methods of correcting for prompt-neutron emission were explored. The results of this study are correlated mass and TKE data.

  8. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the fissile...

  9. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the fissile...

  10. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the fissile...

  11. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the fissile...

  12. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the fissile...

  13. The Application of 238U/235U as a Redox-Proxy for Past Ocean Chemistry

    NASA Astrophysics Data System (ADS)

    Andersen, M. B.; Westermann, S.; Bahniuk, A.; Vasconcelos, C.; McKenzie, J. A.; Föllmi, K. B.; Vance, D.

    2014-12-01

    The recent discovery of significant variation in 238U/235U caused by redox change at the surface Earth has led to its use to extract information on the oxygenation state of ancient oceans from marine sediments [e.g. 1]. Recent studies have focused on improving the understanding of the 238U/235U signature in modern marine carbonates [2] and black shales [3] to improve the robustness of this tracer. To further advance its use we have focused on improving our understanding of 238U/235U systematics in modern dolomite, another commonly occurring rock-type in the geological record, before turning to 238U/235U signatures in ancient sediments. The measured dolomite samples, precipitated in modern environments of coastal hypersaline lagoons in Brazil, all exhibit 238U/235U values that deviate from the seawater composition [3]. Observed values are both lighter (ca. 130 ppm; as also observed in dolomite from tidal-ponds on Bahamas [2]) and heavier (50-180 ppm). These distinct 238U/235U values for different dolomite-precipitates likely attest to the particular formation style, as well as early diagenetic processes. We use such modern settings to discuss the utility of 238U/235U in ancient sediments, the singularity of any observed 238U/235U signal, its relation to global ocean chemistry and potential diagenetic overprinting. These constraints are then used to evaluate a well-preserved marine carbonate section [4] and published black shale 238U/235U data [1], both deposited during the Oceanic Anoxic Event 2 (93 Ma). We discuss the capabilities of both the carbonate and black shale section for retaining information on the 238U/235U composition in the ocean during OAE 2. [1] Montoya-Pino et al. (2010) Geology, 38, 315-318 [2] Romaniello et al. (2013) 362, 305-316 [3] Andersen et al. (2014) EPSL, 400, 184-194 [4] Westermann et al. (2010) Cret. Res., 31, 500-514

  14. Measurement of the^ 235U(n,n')^235mU Integral Cross Section in a Pulsed Reactor

    NASA Astrophysics Data System (ADS)

    Vieira, D. J.; Bond, E. M.; Belier, G.; Meot, V.; Becker, J. A.; Macri, R. A.; Authier, N.; Hyneck, D.; Jacquet, X.; Jansen, Y.; Legrendre, J.

    2009-10-01

    We will present the integral measurement of the neutron inelastic cross section of ^235U leading to the 26-minute, E*=76.5 eV isomer state. Small samples (5-20 microgm) of isotope-enriched ^235U were activated in the central cavity of the CALIBAN pulsed reactor at Valduc where a nearly pure fission neutron spectrum is produced with a typical fluence of 3x10^14 n/cm^2. After 30 minutes the samples were removed from the reactor and counted in an electrostatic-deflecting electron spectrometer that was optimized for the detection of ^235mU conversion electrons. From the decay curve analysis of the data, the 26-minute ^235mU component was extracted. Preliminary results will be given and compared to gamma-cascade calculations assuming complete K-mixing or with no K-mixing.

  15. Evaluation of the 235 U resonance parameters to fit the standard recommended values

    DOE PAGES

    Leal, Luiz; Noguere, Gilles; Paradela, Carlos; ...

    2017-09-13

    A great deal of effort has been dedicated to the revision of the standard values in connection with the neutron interaction for some actinides. While standard data compilation are available for decades nuclear data evaluations included in existing nuclear data libraries (ENDF, JEFF, JENDL, etc.) do not follow the standard recommended values. Indeed, the majority of evaluations for major actinides do not conform to the standards whatsoever. In particular, for the n + 235U interaction the only value in agreement with the standard is the thermal fission cross section. We performed a resonance re-evaluation of the n + 235U interactionmore » in order to address the issues regarding standard values in the energy range from 10-5 eV to 2250 eV. Recently, 235U fission cross-section measurements have been performed at the CERN Neutron Time-o-Flight facility (TOF), known as n_TOF, in the energy range from 0.7 eV to 10 keV. The data were normalized according to the recommended standard of the fission integral in the energy range 7.8 eV to 11 eV. As a result, the n_TOF averaged fission cross sections above 100 eV are in good agreement with the standard recommended values. The n_TOF data were included in the 235U resonance analysis that was performed with the code SAMMY. In addition to the average standard values related to the fission cross section, standard thermal values for fission, capture, and elastic cross sections were also included in the evaluation. Our paper presents the procedure used for re-evaluating the 235U resonance parameters including the recommended standard values as well as new cross section measurements.« less

  16. Evaluation of the 235 U resonance parameters to fit the standard recommended values

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Leal, Luiz; Noguere, Gilles; Paradela, Carlos

    A great deal of effort has been dedicated to the revision of the standard values in connection with the neutron interaction for some actinides. While standard data compilation are available for decades nuclear data evaluations included in existing nuclear data libraries (ENDF, JEFF, JENDL, etc.) do not follow the standard recommended values. Indeed, the majority of evaluations for major actinides do not conform to the standards whatsoever. In particular, for the n + 235U interaction the only value in agreement with the standard is the thermal fission cross section. We performed a resonance re-evaluation of the n + 235U interactionmore » in order to address the issues regarding standard values in the energy range from 10-5 eV to 2250 eV. Recently, 235U fission cross-section measurements have been performed at the CERN Neutron Time-o-Flight facility (TOF), known as n_TOF, in the energy range from 0.7 eV to 10 keV. The data were normalized according to the recommended standard of the fission integral in the energy range 7.8 eV to 11 eV. As a result, the n_TOF averaged fission cross sections above 100 eV are in good agreement with the standard recommended values. The n_TOF data were included in the 235U resonance analysis that was performed with the code SAMMY. In addition to the average standard values related to the fission cross section, standard thermal values for fission, capture, and elastic cross sections were also included in the evaluation. Our paper presents the procedure used for re-evaluating the 235U resonance parameters including the recommended standard values as well as new cross section measurements.« less

  17. Evaluation of the 235U resonance parameters to fit the standard recommended values

    NASA Astrophysics Data System (ADS)

    Leal, Luiz; Noguere, Gilles; Paradela, Carlos; Durán, Ignacio; Tassan-Got, Laurent; Danon, Yaron; Jandel, Marian

    2017-09-01

    A great deal of effort has been dedicated to the revision of the standard values in connection with the neutron interaction for some actinides. While standard data compilation are available for decades nuclear data evaluations included in existing nuclear data libraries (ENDF, JEFF, JENDL, etc.) do not follow the standard recommended values. Indeed, the majority of evaluations for major actinides do not conform to the standards whatsoever. In particular, for the n + 235U interaction the only value in agreement with the standard is the thermal fission cross section. A resonance re-evaluation of the n + 235U interaction has been performed to address the issues regarding standard values in the energy range from 10-5 eV to 2250 eV. Recently, 235U fission cross-section measurements have been performed at the CERN Neutron Time-of-Flight facility (TOF), known as n_TOF, in the energy range from 0.7 eV to 10 keV. The data were normalized according to the recommended standard of the fission integral in the energy range 7.8 eV to 11 eV. As a result, the n_TOF averaged fission cross sections above 100 eV are in good agreement with the standard recommended values. The n_TOF data were included in the 235U resonance analysis that was performed with the code SAMMY. In addition to the average standard values related to the fission cross section, standard thermal values for fission, capture, and elastic cross sections were also included in the evaluation. This paper presents the procedure used for re-evaluating the 235U resonance parameters including the recommended standard values as well as new cross section measurements.

  18. Heterogeneity in the 238U/235U Ratios of Angrites.

    NASA Astrophysics Data System (ADS)

    Tissot, F.; Dauphas, N.; Grove, T. L.

    2016-12-01

    Angrites are differentiated meteorites of basaltic composition, of either volcanic or plutonic origin, that display minimal post-crystallization alteration, metamorphism, shock or impact brecciation. Because quenched angrites cooled very rapidly, all radiochronometric systems closed simultaneously in these samples. Quenched angrites are thus often used as anchors for cross-calibrating short-lived dating methods (e.g., 26Al-26Mg) and the absolute dating techniques (e.g, Pb-Pb). Due to the constancy of the 238U/235U ratio in natural samples, Pb-Pb ages have long been calculated using a "consensus" 238U/235U ratio, but the discovery of resolvable variations in the 238U/235U ratio of natural samples, means that the U isotopic composition of the material to date also has to be determined in order to obtain high-precision Pb-Pb ages. We set out (a) to measure at high-precision the 238U/235U ratio of a large array of angrites to correct their Pb-Pb ages, and (b) to identify whether all angrites have a similar U isotopic composition, and, if not, what were the processes responsible for this variability. Recently, Brennecka & Wadhwa (2012) suggested that the angrite-parent body had a homogeneous 238U/235U ratio. They reached this conclusion partly because they propagated the uncertainties of the U isotopic composition of the various U double spikes that they used onto the final 238U/235U ratio the sample. Because this error is systematic (i.e., it affects all samples similarly), differences in the δ238U values of samples corrected by the same double spike are better known than one would be led to believe if uncertainties on the spike composition are propagated. At the conference, we will present the results of the high-precision U isotope analyses for six angrite samples: NWA 4590, NWA 4801, NWA 6291, Angra dos Reis, D'Orbigny, and Sahara 99555. We will show that there is some heterogeneity in the δ238U values of the angrites and will discuss the possible processes by

  19. Field Application of 238U/235U Measurements To Detect Reoxidation and Mobilization of U(IV).

    PubMed

    Jemison, Noah E; Shiel, Alyssa E; Johnson, Thomas M; Lundstrom, Craig C; Long, Philip E; Williams, Kenneth H

    2018-03-20

    Biostimulation to induce reduction of soluble U(VI) to relatively immobile U(IV) is an effective strategy for decreasing aqueous U(VI) concentrations in contaminated groundwater systems. If oxidation of U(IV) occurs following the biostimulation phase, U(VI) concentrations increase, challenging the long-term effectiveness of this technique. However, detecting U(IV) oxidation through dissolved U concentrations alone can prove difficult in locations with few groundwater wells to track the addition of U to a mass of groundwater. We propose the 238 U/ 235 U ratio of aqueous U as an independent, reliable tracer of U(IV) remobilization via oxidation or mobilization of colloids. Reduction of U(VI) produces 238 U-enriched U(IV), whereas remobilization of solid U(IV) should not induce isotopic fractionation. The incorporation of remobilized U(IV) with a high 238 U/ 235 U ratio into the aqueous U(VI) pool produces an increase in 238 U/ 235 U of aqueous U(VI). During several injections of nitrate to induce U(IV) oxidation, 238 U/ 235 U consistently increased, suggesting 238 U/ 235 U is broadly applicable for detecting mobilization of U(IV).

  20. Fractionation of 238U/235U by reduction during low temperature uranium mineralisation processes

    NASA Astrophysics Data System (ADS)

    Murphy, Melissa J.; Stirling, Claudine H.; Kaltenbach, Angela; Turner, Simon P.; Schaefer, Bruce F.

    2014-02-01

    Investigations of ‘stable’ uranium isotope fractionation during low temperature, redox transformations may provide new insights into the usefulness of the 238U/235U isotope system as a tracer of palaeoredox processes. Sandstone-hosted uranium deposits accumulate at an oxidation/reduction interface within an aquifer from the low temperature reduction of soluble U(VI) complexes in groundwaters, forming insoluble U(IV) minerals. This setting provides an ideal environment in which to investigate the effects of redox transformations on 238U/235U fractionation. Here we present the first coupled measurements of 238U/235U isotopic compositions and U concentrations for groundwaters and mineralised sediment samples from the same redox system in the vicinity of the high-grade Pepegoona sandstone-hosted uranium deposit, Australia. The mineralised sediment samples display extremely variable 238U/235U ratios (herein expressed as δUCRM145238, the per-mil deviation from the international NBL standard CRM145). The majority of mineralised sediment samples have δUCRM145238 values between -1.30±0.05 and 0.55±0.12‰, spanning a ca. 2‰ range. However, one sample has an unusually light isotopic composition of -4.13±0.05‰, which suggests a total range of U isotopic variability of up to ca. 5‰, the largest variation found thus far in a single natural redox system. The 238U/235U isotopic signature of the mineralised sediments becomes progressively heavier (enriched in 238U) along the groundwater flow path. The groundwaters show a greater than 2‰ variation in their 238U/235U ratios, ranging from δUCRM145238 values of -2.39±0.07 to -0.71±0.05‰. The majority of the groundwater data exhibit a clear systematic relationship between 238U/235U isotopic composition and U concentration; samples with the lowest U concentrations have the lowest 238U/235U ratios. The preferential incorporation of 238U during reduction of U(VI) to U(IV) and precipitation of uranium minerals leaves

  1. Observations of 231Pa/ 235U disequilibrium in volcanic rocks

    NASA Astrophysics Data System (ADS)

    Pickett, David A.; Murrell, Michael T.

    1997-04-01

    We present here the first survey of ( 231Pa/ 235U) ratios in volcanic rocks; such measurements are made possible by new mass spectrometric techniques. The data place new constraints on the timing and extent of magma source and evolutionary processes, particularly due to the sensitivity of the 231Pa- 235U pair and its intermediate time scale ( 231Pat 1/2 = 33 ky). ( 231Pa/ 235U) is found to vary widely, from 0.2 in carbonatites to 1.1-2.9 in basalts and 0.9-2.2 in arcs. Substantial Pa enrichment is nearly ubiquitous, suggestive of the relative incompatibility of Pa, qualitatively consistent with available partitioning data. The level of 231Pa- 235U disequilibrium typically far exceeds that of 230Th- 238U and is comparable to 226Ra- 230Th. The high ( 231Pa/ 235U) ratios in MORB and other basalts reflect a large degree of discrimination between two incompatible elements, posing challenges for modelling of melt generation and migration. Fundamental differences in ( 231Pa/ 235U) among different basaltic environments are likely related to contrasts in melting zone conditions (e.g., melting rate). Strong ( 231Pa/ 235U) disequilibria in continental basalts, for which ( 230Th/ 238U) disequilibria are small or absent, demonstrate that Pa-U fractionation is possible in both garnet and spinel mantle stability fields. In arcs, correlation of ( 231Pa/ 235U) and ( 230Th/ 238U) is consistent with U enrichment via slab-derived fluids, a process which is additional to the still dominant Pa enrichment. An important new constraint is provided by the observation that the near-equilibrium ( 230Th/ 238U) common to arcs and continental basalts is not typically accompanied by near-equilibrium ( 231Pa/ 235U), arguing against the influence of long magma history, crustal material, or equilibrium mantle sources in affecting decay-series ratios. Small sample sets from two silicic centers illustrate: (1) recent, rapid U enrichment in the magma chamber (El Chichón); and (2) the failure of

  2. Nuclear Excitation by Electronic Transition of U-235

    NASA Astrophysics Data System (ADS)

    Chodash, Perry

    2017-01-01

    Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is theorized to exist in numerous isotopes. NEET is the inverse of bound internal conversion and occurs when an electronic transition couples to a nuclear transition causing the nucleus to enter an excited state. This process can only occur for isotopes with low-lying nuclear levels due to the requirement that the electronic and nuclear transitions have similar energies. One of the candidate isotopes for NEET, 235U, has been studied several times over the past 40 years and NEET of 235U has never been conclusively observed. These past experiments generated conflicting results with some experiments claiming to observe NEET of 235U and others setting limits for the NEET rate. If NEET of 235U were to occur, the uranium would be excited to its first excited nuclear state. The first excited nuclear state in 235U is only 76 eV, the second lowest known nuclear state. Additionally, the 76 eV state is a nuclear isomer that decays by internal conversion with a half-life of 26 minutes. In order to measure whether NEET occurs in 235U and at what rate, a uranium plasma was required. The plasma was generated using a Q-switched Nd:YAG laser outputting 789 mJ pulses of 1064 nm light. The laser light was focused onto uranium targets generating an intensity on target of order 1012 W/cm2. The resulting plasma was captured on a catcher plate and electrons emitted from the catcher plate were accelerated and focused onto a microchannel plate detector. Measurements performed using a variety of uranium targets spanning depleted uranium up to 99.4% enriched uranium did not observe a 26 minute decay. An upper limit for the NEET rate of 235U was determined. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. The U.S. DHS, UC Berkeley, the NNIS fellowship and the NSSC further supported this work.

  3. Determination of 235U/238U Ratio on Urine by ICP-MS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Collins, L; Gobaleza, A; Langston, R

    2011-10-19

    LLNL Internal Dosimetry Program - The new procedure satisfies the requirement to determine {sup 235}U/{sup 238}U ratio in bioassay urine samples. MDA - The L{sub C} and MDA{sub 95} for {sup 235}U are well below the required detection limit of 0.00035 {mu}g/L. Turn around time - Analysis of 10 samples plus 2 QCs can be completed in one work day (8 hours).

  4. Integral cross section measurement of the U 235 ( n , n ' ) U 235 m reaction in a pulsed reactor

    DOE PAGES

    Bélier, G.; Bond, E. M.; Vieira, D. J.; ...

    2015-04-08

    The integral measurement of the neutron inelastic cross section leading to the 26-minute half-life 235mU isomer in a fission-like neutron spectrum is presented. The experiment has been performed at a pulsed reactor, where the internal conversion decay of the isomer was measured using a dedicated electron detector after activation. The sample preparation, efficiency measurement, irradiation, radiochemistry purification, and isomer decay measurement will be presented. We determined the integral cross section for the ²³⁵U(n,n') 235mU reaction to be 1.00±0.13b. This result supports an evaluation performed with TALYS-1.4 code with respect to the isomer excitation as well as the total neutron inelasticmore » scattering cross section.« less

  5. Dispersion of the Neutron Emission in U{sup 235} Fission

    DOE R&D Accomplishments Database

    Feynman, R. P.; de Hoffmann, F.; Serber, R.

    1955-01-01

    Equations are developed which allow the calculation of the average number of neutrons per U{sup235} fission from experimental measurements. Experimental methods are described, the results of which give a value of (7.8 + 0.6){sup ?} neutrons per U{sup 235} thermal fission.

  6. 235U enrichment determination on UF6 cylinders with CZT detectors

    NASA Astrophysics Data System (ADS)

    Berndt, Reinhard; Mortreau, Patricia

    2018-04-01

    Measurements of uranium enrichment in UF6 transit cylinders are an important nuclear safeguards verification task, which is performed using a non-destructive assay method, the traditional enrichment meter, which involves measuring the count rate of the 186 keV gamma ray. This provides a direct measure of the 235U enrichment. Measurements are typically performed using either high-resolution detectors (Germanium) with e-cooling and battery operation, or portable devices equipped with low resolution detectors (NaI). Despite good results being achieved when measuring Low Enriched Uranium in 30B type cylinders and natural uranium in 48Y type containers using both detector systems, there are situations, which preclude the use of one or both of these systems. The focus of this work is to address some of the recognized limitations in relation to the current use of the above detector systems by considering the feasibility of an inspection instrument for 235U enrichment measurements on UF6 cylinders using the compact and light Cadmium Zinc Telluride (CZT) detectors. In the present work, test measurements were carried out, under field conditions and on full-size objects, with different CZT detectors, in particular for situations where existing systems cannot be used e.g. for stacks of 48Y type containers with depleted uranium. The main result of this study shows that the CZT detectors, actually a cluster of four μCZT1500 micro spectrometers provide as good results as the germanium detector in the ORTEC Micro-trans SPEC HPGe Portable spectrometer, and most importantly in particular for natural and depleted uranium in 48Y cylinders.

  7. A modern framework for the interpretation of 238U/235U in studies of ancient ocean redox

    NASA Astrophysics Data System (ADS)

    Andersen, M. B.; Romaniello, S.; Vance, D.; Little, S. H.; Herdman, R.; Lyons, T. W.

    2014-08-01

    The abundance and isotope composition of redox sensitive elements in ancient sediments are increasingly used to understand the past ocean's geochemical state and the oxygenation history of the Earth. The redox transition of uranium (U) from soluble U+6 to relatively insoluble U+4 and its subsequent incorporation into reduced sediments has been used to deduce the redox state of the oceans in the past. Furthermore, recent analytical improvements have revealed significant 238U/235U fractionation during this redox transition, offering the potential for U isotopes to act as a redox proxy. However, the development of U isotopes as a geochemical tracer requires that U isotope systematics associated with redox changes, are well-characterized. This study focuses on U isotopes in recent sediments from the two largest modern anoxic ocean basins, the Black Sea and the Cariaco Basin, with the aim of advancing our understanding of the U isotope systematics in reducing marine environments. These anoxic sediments have high U accumulation rates and high 238U/235U ratios relative to seawater, in general agreement with a process that accumulates reduced U with a heavy isotopic composition. Using Al and Ca concentrations to correct for detrital and biogenic carbonate-bound U, we estimate the reduced authigenic U accumulated in the sediments and its 238U/235U. These results highlight the importance of isotopic mass balance constraints during diffusive transport and reaction of U from seawater and through pore-water, affecting the observed 238U/235U in sediments. Using these constraints, the average percentages of U depletion from top to bottom of the water column can be estimated, assuming batch-removal of U into anoxic sediments in a restricted basin. Using this framework, 238U/235U in modern anoxic sediments from the Black Sea imply U depletions in the water column of ∼30%, which is close to the observed ∼40% U depletion in the modern Black Sea water column at these depths

  8. Computer program FPIP-REV calculates fission product inventory for U-235 fission

    NASA Technical Reports Server (NTRS)

    Brown, W. S.; Call, D. W.

    1967-01-01

    Computer program calculates fission product inventories and source strengths associated with the operation of U-235 fueled nuclear power reactor. It utilizes a fission-product nuclide library of 254 nuclides, and calculates the time dependent behavior of the fission product nuclides formed by fissioning of U-235.

  9. Reaction paths and host phases of uranium isotopes (235U; 238U), Saanich Inlet

    NASA Astrophysics Data System (ADS)

    Amini, M.; Holmden, C. E.; Francois, R. H.

    2009-12-01

    In recent times, Uranium has become increasingly the focus of stable isotope fractionation studies. Variations in 238U/235U have been reported as a result of redox reactions [1,2] from the nuclear field shift effect [3], and a mass-dependent, microbially-mediated, kinetic isotope effect [4]. The 238U/235U variability caused by changes in environmental redox conditions leads to an increase in the 238U/235U ratios of the reduced U species sequestered into marine sediments. This points to U isotope variability as a new tool to study ancient ocean redox changes. However, the process by which reduced sediments become enriched in the heavy isotopes of U is not yet known, and hence the utility of 238U/235U as a redox tracer remains to be demonstrated. In order to further constrain sedimentary U enrichment and related isotope effect, we are investigating U isotopic compositions of water samples and fresh surface sediment grab samples over a range of redox conditions in the seasonally anoxic Saanich Inlet, on the east coast of Vancouver Island. U was sequentially extracted from sediments in order to characterize specific fractions for their isotopic composition. The measurements were carried out by MC-ICPMS using 233U/236U-double spike technique. The data are reported as δ238U relative to NBL 112a with a 238U/235U ratio of 137.88 (2sd). External precision is better than 0.10‰ (2sd). Fifteeen analyses of seawater yielded δ238U of -0.42±0.08‰ (2sd). The results for the water samples indicate a homogenous δ238U value throughout the Saanich Inlet water column that matches the global seawater signature. All of the water samples from above and below average -0.42±0.05‰ (2sd). In contrast, a plankton net sample yielded a distinctly different, (about 0.5‰ lighter) isotope value. Bacterial reduction experiments [4] have also shown isotope enrichment factors of about -0.3‰. In addition, metal isotope fractionation occurs during adsorption with the light isotope being

  10. Studies of Neutron-Induced Fission of 235U, 238U, and 239Pu

    NASA Astrophysics Data System (ADS)

    Duke, Dana; TKE Team

    2014-09-01

    A Frisch-gridded ionization chamber and the double energy (2E) analysis method were used to study mass yield distributions and average total kinetic energy (TKE) release from neutron-induced fission of 235U, 238U, and 239Pu. Despite decades of fission research, little or no TKE data exist for high incident neutron energies. Additional average TKE information at incident neutron energies relevant to defense- and energy-related applications will provide a valuable observable for benchmarking simulations. The data can also be used as inputs in theoretical fission models. The Los Alamos Neutron Science Center-Weapons Neutron Research (LANSCE - WNR) provides a neutron beam from thermal to hundreds of MeV, well-suited for filling in the gaps in existing data and exploring fission behavior in the fast neutron region. The results of the studies on 238U, 235U, and 239Pu will be presented. LA-UR-14-24921.

  11. Nuclear Resonance Fluorescence of U-235 above 3 MeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Warren, Glen A.; Caggiano, Joseph A.; Miller, Erin A.

    Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct measurements to search for a nuclear resonance fluorescence response of U-235 from 3 to 5 MeV using an 8 g sample of highly enriched uranium. These new measurements complement previously reported measurements below 3 MeV. Preliminary analysis indicates that no strong resonances exist for U-235 in this energy range. A second set of measurements focused on a signature search in the 5 to 10 MeV range is still under analysis.

  12. Measurement of 235U(n,n'γ) and 235U(n,2nγ) reaction cross sections

    NASA Astrophysics Data System (ADS)

    Kerveno, M.; Thiry, J. C.; Bacquias, A.; Borcea, C.; Dessagne, P.; Drohé, J. C.; Goriely, S.; Hilaire, S.; Jericha, E.; Karam, H.; Negret, A.; Pavlik, A.; Plompen, A. J. M.; Romain, P.; Rouki, C.; Rudolf, G.; Stanoiu, M.

    2013-02-01

    The design of generation IV nuclear reactors and the studies of new fuel cycles require knowledge of the cross sections of various nuclear reactions. Our research is focused on (n,xnγ) reactions occurring in these new reactors. The aim is to measure unknown cross sections and to reduce the uncertainty on present data for reactions and isotopes of interest for transmutation or advanced reactors. The present work studies the 235U(n,n'γ) and 235U(n,2nγ) reactions in the fast neutron energy domain (up to 20 MeV). The experiments were performed with the Geel electron linear accelerator GELINA, which delivers a pulsed white neutron beam. The time characteristics enable measuring neutron energies with the time-of-flight (TOF) technique. The neutron induced reactions [in this case inelastic scattering and (n,2n) reactions] are identified by on-line prompt γ spectroscopy with an experimental setup including four high-purity germanium (HPGe) detectors. A fission ionization chamber is used to monitor the incident neutron flux. The experimental setup and analysis methods are presented and the model calculations performed with the TALYS-1.2 code are discussed.

  13. 238U and 235U isotope fractionation upon oxidation of uranium-bearing rocks by fracture waters

    NASA Astrophysics Data System (ADS)

    Chernyshev, I. V.; Golubev, V. N.; Chugaev, A. V.; Mandzhieva, G. V.

    2016-10-01

    The variations in 238U/235U values accompanying mobilization of U by fracture waters from uranium-bearing rocks, in which U occurs as a fine impregnation of oxides and silicates, were studied by the high-precision (±0.07‰) MC-ICP-MS method. Transition of U into the aqueous phase in the oxidized state U(VI) is accompanied by its isotope fractionation with enrichment of dissolved U(VI) in the heavy isotope 238U up to 0.32‰ in relation to the composition of the solid phases. According to the sign, this effect is consistent with the tendency of the behavior of 238U and 235U upon interaction of river waters with rocks of the catchment areas [11] and with the effect observed during oxidation of uraninite by the oxygen-bearing NaHCO3 solution [12].

  14. ^2^3^8U/^2^3^5U Ratios of Anagrams: Angrites and Granites

    NASA Astrophysics Data System (ADS)

    Tissot, F. L. H.; Dauphas, N.

    2012-03-01

    We report ^2^3^8U/^2^3^5U ratios of five angrites and give the corresponding Pb-Pb ages of D'Orbigny and Angra Dos Reis. The U-isotopic composition of terrestrial granites (I, S, and A types) is also assessed to determine the influence of the protolith.

  15. Towards A Modern Calibration Of The 238U/235U Paleoredox Proxy: Apparent Uranium Isotope Fractionation Factor During U(VI)-U(IV) Reduction In The Black Sea

    NASA Astrophysics Data System (ADS)

    Rolison, J. M.; Stirling, C. H.; Middag, R.; Rijkenberg, M. J. A.; De Baar, H. J. W.

    2015-12-01

    The isotopic compositions of redox-sensitive metals, including uranium (U), in marine sediments have recently emerged as powerful diagnostic tracers of the redox state of the ancient ocean-atmosphere system. Interpretation of sedimentary isotopic information requires a thorough understating of the environmental controls on isotopic fractionation in modern anoxic environments before being applied to the paleo-record. In this study, the relationship between ocean anoxia and the isotopic fractionation of U was investigated in the water column and sediments of the Black Sea. The Black Sea is the world's largest anoxic basin and significant removal of U from the water column and high U accumulation rates in modern underlying sediments have been documented. Removal of U from the water column occurs during the redox transition of soluble U(VI) to relatively insoluble U(IV). The primary results of this study are two-fold. First, significant 238U/235U fractionation was observed in the water column of the Black Sea, suggesting the reduction of U induces 238U/235U fractionation with the preferential removal of 238U from the aqueous phase. Second, the 238U/235U of underlying sediments is related to the water column through the isotope fractionation factor of the reduction reaction but is influenced by mass transport processes. These results provide important constraints on the use of 238U/235U as a proxy of the redox state of ancient oceans.

  16. On the Search for Nuclear Resonance Fluorescence Signatures of 235U and 238U above 3 MeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Warren, Glen A.; Caggiano, Joseph A.; Bertozzi, William

    Nuclear resonance fluorescence is a physical process that provides an isotope-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample that is exposed to MeV-energy photons. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials such as 235U. Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct a pair of measurements to search for a nuclear resonance fluorescence response of 235U above 3 MeV and of 238U above 5 MeV using an 8 gmore » sample of highly enriched uranium and a 90 g sample of depleted uranium. No new signatures were observed. The minimum detectable integrated cross section for 235U is presented.« less

  17. Nuclear excitation by electronic transition of 235U

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chodash, P. A.; Norman, E. B.; Burke, J. T.

    Here, nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that can occur in isotopes containing a low-lying nuclear excited state. Over the past 40 yr, several experiments have attempted to measure NEET of 235U and those experiments have yielded conflicting results.

  18. Nuclear excitation by electronic transition of 235U

    DOE PAGES

    Chodash, P. A.; Norman, E. B.; Burke, J. T.; ...

    2016-03-11

    Here, nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that can occur in isotopes containing a low-lying nuclear excited state. Over the past 40 yr, several experiments have attempted to measure NEET of 235U and those experiments have yielded conflicting results.

  19. The Effect of Early Diagenesis on the 238U/235U Ratio of Platform Carbonates.

    NASA Astrophysics Data System (ADS)

    Tissot, F.; Chen, C.; Go, B. M.; Naziemiec, M.; Healy, G.; Swart, P. K.; Dauphas, N.

    2017-12-01

    In the past 15 years, the so-called non-traditional stable isotopes systems (e.g., Mg, Fe, Mo, U) have emerged as powerful tracers of both high-T and low-T geochemical processes (e.g., [1]). Of particular interest for paleoredox studies is the ratio of "stable" isotopes of U (238U/235U), which has the potential to track the global extent of oceanic anoxia (e.g., [2, 3]). Indeed, in the modern ocean, U exists in two main oxidation states, soluble U6+ and insoluble U4+, and has a mean residence time of 400 kyr ([4]), much longer than the global ocean mixing time (1-2 kyr). As such the salinity-normalized ocean is homogeneous with regards to both U concentrations and isotopes (δ238USW = -0.392±0.005 ‰, [2]). The value of δ238USW at any given time is therefore the balance between U input to the ocean, mainly from rivers, and U removal, mostly into biogenic carbonates, anoxic/euxinic sediments and suboxic/hypoxic sediments (e.g., [2, 5]). Because the 238U/235U ratio of the past ocean cannot be measured directly, it has to be estimated from the measurement of the 238U/235U ratio of a sedimentary rock and assuming a constant fractionation factor. Carbonates appear as a promising record since they span most of Earth's history, and the δ238U values of modern primary carbonate precipitates and well-preserved fossil aragonitic coral up to 600 ka are indistinguishable from that of seawater (e.g., [2, 6, 7]). Yet, the effect of secondary processes on the δ238U values of non-coral carbonates, which represent the bulk of the rock record, has only been studied in a handful of shallow samples (down to 40cm, [6]) and remains poorly understood. To investigate the effect of early diagenesis on the 238U/235U ratio of carbonates on the 30kyr to 1Myr timescale, we measured δ13C, δ18O, and δ238U in samples from a 220m long drill core from the Bahamas carbonate platform. In order to separate lattice bound U from secondary U we developed a leaching protocol applicable to carbonate

  20. ^235U(n,xnγ) Excitation Function Measurements Using Gamma-Ray Spectroscopy at GEANIE

    NASA Astrophysics Data System (ADS)

    Younes, W.; Becker, J. A.; Bernstein, L. A.; Archer, D. E.; Stoyer, M. A.; Hauschild, K.; Drake, D. M.; Johns, G. D.; Nelson, R. O.; Wilburn, S. W.

    1998-04-01

    The ^235U(n,xn) cross sections (where x<=2) have previously been measured at several incident neutron energies. In particular, the ^235U(n,2n) cross section has been measured(J. Frehaut et al.), Nucl. Sci. Eng. 74,29 (1980). reliably up to peak near E_n≈ 11 MeV, but not along the tail which is predicted by some(M.B. Chadwick, private communication.) codes to yield significant (e.g. >= 10% of peak) cross section out to E_n≈ 30 MeV. We have measured gamma-ray spectra resulting from ^235U(n,xn) as a function of neutron energy in the range 1 MeV <~ En <~ 200 MeV using the GEANIE spectrometer at the LANSCE/WNR ``white'' neutron source. We will present excitation functions for the de-excitation gamma rays in ^234,235U compared to predictions from the Hauser-Feshbach-preequilibrium code GNASH(M.B. Chadwick and P.G. Young, Los Alamos Report No. LA-UR-93-104, 1993.).

  1. On the Search for Nuclear Resonance Fluorescence Signatures of 235U and 238U above 3 MeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Warren, Glen A.; Caggiano, Joseph A.; Bertozzi, William

    Abstract–Nuclear resonance fluorescence is a physical process that provides an isotope-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample that is exposed to photons in the MeV energy range. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials such as 235U. Pacific Northwest National Laboratory and Passport Systems have collaborated to conduct a a pair of measurements to search for a nuclear resonance fluorescence response of 235U above 3 MeV and of 238U above 5more » MeV using an 8 g sample of highly enriched uranium and a 90 g sample of depleted uranium. No new signatures were observed. The minimum detectable integrated cross section for 235U is presented.« less

  2. Using 238U/235U ratios to understand the formation and oxidation of reduced uranium solids in naturally reduced zones

    NASA Astrophysics Data System (ADS)

    Jemison, N.; Johnson, T. M.; Druhan, J. L.; Davis, J. A.

    2016-12-01

    Uranium occurs in groundwater primarily as soluble and mobile U(VI), which can be reduced to immobile U(IV), often observed in sediments as uraninite. Numerous U(VI)-contaminated sites, such as the DOE field site in Rifle, CO, contain naturally reduced zones (NRZ's) that have relatively high concentrations of organic matter. Reduction of heavy metals occurs within NRZ's, producing elevated concentrations of iron sulfides and U(IV). Slow, natural oxidation of U(IV) from NRZ's may prolong U(VI) contamination of groundwater. The reduction of U(VI) produces U(IV) with a higher 238U/235U ratio. Samples from two NRZ sediment cores recovered from the Rifle site revealed that the outer fringes of the NRZ contain U(IV) with a high 238U/235U ratio, while lower values are observed in the center . We suggest that as aqueous U(VI) was reduced in the NRZ, it was driven to lower 238U/235U values, such that U(IV) formed in the core of the NRZ reflects a lower 238U/235U. Two oxidation experiments were conducted by injecting groundwater containing between 14.9 and 21.2 mg/L dissolved O2 as an oxidant into the NRZ. The oxidation of U(IV) from this NRZ increased aqueous U(VI) concentrations and caused a shift to higher 238U/235U in groundwater as U(IV) was oxidized primarily on the outer fringes of the NRZ. In total these observations suggest that the stability of solid phase uranium is governed by coupled reaction and transport processes. To better understand various reactive transport scenarios we developed a model for the formation and oxidation of NRZ's utilizing the reactive transport software CrunchTope. These simulations suggest that the development of isotopically heterogeneous U(IV) within NRZ's is largely controlled by permeability of the NRZ and the U(VI) reduction rate. Oxidation of U(IV) from the NRZ's is constrained by the oxidation rate of U(IV) as well as iron sulfides, which can prevent oxidation of U(IV) by scavenging dissolved oxygen.

  3. Theoretical Model for Volume Fraction of UC, 235U Enrichment, and Effective Density of Final U 10Mo Alloy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Devaraj, Arun; Prabhakaran, Ramprashad; Joshi, Vineet V.

    2016-04-12

    The purpose of this document is to provide a theoretical framework for (1) estimating uranium carbide (UC) volume fraction in a final alloy of uranium with 10 weight percent molybdenum (U-10Mo) as a function of final alloy carbon concentration, and (2) estimating effective 235U enrichment in the U-10Mo matrix after accounting for loss of 235U in forming UC. This report will also serve as a theoretical baseline for effective density of as-cast low-enriched U-10Mo alloy. Therefore, this report will serve as the baseline for quality control of final alloy carbon content

  4. Fission Product Yields of 233U, 235U, 238U and 239Pu in Fields of Thermal Neutrons, Fission Neutrons and 14.7-MeV Neutrons

    NASA Astrophysics Data System (ADS)

    Laurec, J.; Adam, A.; de Bruyne, T.; Bauge, E.; Granier, T.; Aupiais, J.; Bersillon, O.; Le Petit, G.; Authier, N.; Casoli, P.

    2010-12-01

    The yields of more than fifteen fission products have been carefully measured using radiochemical techniques, for 235U(n,f), 239Pu(n,f) in a thermal spectrum, for 233U(n,f), 235U(n,f), and 239Pu(n,f) reactions in a fission neutron spectrum, and for 233U(n,f), 235U(n,f), 238U(n,f), and 239Pu(n,f) for 14.7 MeV monoenergetic neutrons. Irradiations were performed at the EL3 reactor, at the Caliban and Prospero critical assemblies, and at the Lancelot electrostatic accelerator in CEA-Valduc. Fissions were counted in thin deposits using fission ionization chambers. The number of fission products of each species were measured by gamma spectrometry of co-located thick deposits.

  5. The 238U/235U isotope ratio of the Earth and the solar system: Constrains from a gravimetrically calibrated U double spike and implications for absolute Pb-Pb ages

    NASA Astrophysics Data System (ADS)

    Weyer, Stefan; Noordmann, Janine; Brennecka, Greg; Richter, Stephan

    2010-05-01

    The ratio of 238U and 235U, the two primordial U isotopes, has been assumed to be constant on Earth and in the solar system. The commonly accepted value for the 238U/235U ratio, which has been used in Pb-Pb dating for the last ~ 30 years, was 137.88. Within the last few years, it has been shown that 1) there are considerable U isotope variations (~1.3‰) within terrestrial material produced by isotope fractionation during chemical reactions [1-3] and 2) there are even larger isotope variations (at least 3.5‰) in calcium-aluminum-rich inclusions (CAIs) in meoteorites that define the currently accepted age of the solar system [4]. These findings are dramatic for geochronology, as a known 238U/235U is a requirement for Pb-Pb dating, the most precise dating technique for absolute ages. As 238U/235U variations can greatly affect the reported absolute Pb-Pb age, understanding and accurately measuring variation of the 238U/235U ratio in various materials is critical, With these new findings, the questions also arises of "How well do we know the average U isotope composition of the Earth and the solar system?" and "How accurate can absolute Pb-Pb ages be?" Our results using a gravimetrically calibrated 233U/236U double spike IRMM 3636 [5] indicate that the U standard NBL 950a, which was commonly used to define the excepted "natural" 238U/235U isotope ratio, has a slightly lower 238U/235U of 137.836 ± 0.024. This value is indistinguishable from the U isotope compositions for NBL 960 and NBL112A, which have been determined by several laboratories, also using the newly calibrated U double spike IRMM 3636 [6]. These findings provide new implications about the average U isotope composition of the Earth and the solar system. Basalts display a very tight range of U isotope variations (~0.25-0.32‰ relative to SRM 950a). Their U isotope composition is also very similar to that of chondrites [4], which however appear to show a slightly larger spread. Accepting terrestrial

  6. Uranium 238U/235U isotope ratios as indicators of reduction: Results from an in situ biostimulation experiment at Rifle, Colorado, USA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bopp IV, C.J.; Lundstrom, C.C.; Johnson, T.M.

    2010-02-01

    The attenuation of groundwater contamination via chemical reaction is traditionally evaluated by monitoring contaminant concentration through time. However, this method can be confounded by common transport processes (e.g. dilution, sorption). Isotopic techniques bypass the limits of concentration methods, and so may provide improved accuracy in determining the extent of reaction. We apply measurements of {sup 238}U/{sup 235}U to a U bioremediation field experiment at the Rifle Integrated Field Research Challenge Site in Rifle, Colorado (USA). An array of monitoring and injection wells was installed on a 100 m{sup 2} plot where U(VI) contamination was present in the groundwater. Acetate-amended groundwatermore » was injected along an up-gradient gallery to encourage the growth of dissimilatory metal reducing bacteria (e.g. Geobacter species). During amendment, U concentration dropped by an order of magnitude in the experiment plot. We measured {sup 238}U/{sup 235}U in samples from one monitoring well by MC-ICP-MS using a double isotope tracer method. A significant {approx}1.00{per_thousand} decrease in {sup 238}U/{sup 235}U occurred in the groundwater as U(VI) concentration decreased. The relationship between {sup 238}U/{sup 235}U and concentration corresponds approximately to a Rayleigh distillation curve with an effective fractionation factor ({alpha}) of 1.00046. We attribute the observed U isotope fractionation to a nuclear field shift effect during enzymatic reduction of U(VI){sub (aq)} to U(IV){sub (s)}.« less

  7. Quantification of 235U and 238U activity concentrations for undeclared nuclear materials by a digital gamma-gamma coincidence spectroscopy.

    PubMed

    Zhang, Weihua; Yi, Jing; Mekarski, Pawel; Ungar, Kurt; Hauck, Barry; Kramer, Gary H

    2011-06-01

    The purpose of this study is to investigate the possibility of verifying depleted uranium (DU), natural uranium (NU), low enriched uranium (LEU) and high enriched uranium (HEU) by a developed digital gamma-gamma coincidence spectroscopy. The spectroscopy consists of two NaI(Tl) scintillators and XIA LLC Digital Gamma Finder (DGF)/Pixie-4 software and card package. The results demonstrate that the spectroscopy provides an effective method of (235)U and (238)U quantification based on the count rate of their gamma-gamma coincidence counting signatures. The main advantages of this approach over the conventional gamma spectrometry include the facts of low background continuum near coincident signatures of (235)U and (238)U, less interference from other radionuclides by the gamma-gamma coincidence counting, and region-of-interest (ROI) imagine analysis for uranium enrichment determination. Compared to conventional gamma spectrometry, the method offers additional advantage of requiring minimal calibrations for (235)U and (238)U quantification at different sample geometries. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  8. Improvement of voltage holding capability in the 500 keV negative ion source for JT-60SA.

    PubMed

    Tanaka, Y; Hanada, M; Kojima, A; Akino, N; Shimizu, T; Ohshima, K; Inoue, T; Watanabe, K; Taniguchi, M; Kashiwagi, M; Umeda, N; Tobari, H; Grisham, L R

    2010-02-01

    Voltage holding capability of JT-60 negative ion source that has a large electrostatic negative ion accelerator with 45 cm x 1.1 m acceleration grids was experimentally examined and improved to realize 500 keV, 22 A, and 100 s D- ion beams for JT-60 Super Advanced. The gap lengths in the acceleration stages were extended to reduce electric fields in a gap between the large grids and at the corner of the support flanges from the original 4-5 to 3-4 kV/mm. As a result, the voltage holding capability without beam acceleration has been successfully improved from 400 to 500 kV. The pulse duration to hold 500 kV reached 40 s of the power supply limitation.

  9. Photon-induced Fission Product Yield Measurements on 235U, 238U, and 239Pu

    NASA Astrophysics Data System (ADS)

    Krishichayan, Fnu; Bhike, M.; Tonchev, A. P.; Tornow, W.

    2015-10-01

    During the past three years, a TUNL-LANL-LLNL collaboration has provided data on the fission product yields (FPYs) from quasi-monoenergetic neutron-induced fission of 235U, 238U, and 239Pu at TUNL in the 0.5 to 15 MeV energy range. Recently, we have extended these experiments to photo-fission. We measured the yields of fission fragments ranging from 85Kr to 147Nd from the photo-fission of 235U, 238U, and 239Pu using 13-MeV mono-energetic photon beams at the HIGS facility at TUNL. First of its kind, this measurement will provide a unique platform to explore the effect of the incoming probe on the FPYs, i.e., photons vs. neutrons. A dual-fission ionization chamber was used to determine the number of fissions in the targets and these samples (along with Au monitor foils) were gamma-ray counted in the low-background counting facility at TUNL. Details of the experimental set-up and results will be presented and compared to the FPYs obtained from neutron-induced fission at the same excitation energy of the compound nucleus. Work supported in part by the NNSA-SSAA Grant No. DE-NA0001838.

  10. Beta decay heat following U-235, U-238 and Pu-239 neutron fission

    NASA Astrophysics Data System (ADS)

    Li, Shengjie

    1997-09-01

    This is an experimental study of beta-particle decay heat from 235U, 239Pu and 238U aggregate fission products over delay times 0.4-40,000 seconds. The experimental results below 2s for 235U and 239Pu, and below 20s for 238U, are the first such results reported. The experiments were conducted at the UMASS Lowell 5.5-MV Van de Graaff accelerator and 1-MW swimming-pool research reactor. Thermalized neutrons from the 7Li(p,n)7Be reaction induced fission in 238U and 239Pu, and fast neutrons produced in the reactor initiated fission in 238U. A helium-jet/tape-transport system rapidly transferred fission fragments from a fission chamber to a low background counting area. Delay times after fission were selected by varying the tape speed or the position of the spray point relative to the beta spectrometer that employed a thin-scintillator-disk gating technique to separate beta-particles from accompanying gamma-rays. Beta and gamma sources were both used in energy calibration. Based on low-energy(<1 MeV) internal-conversion electron studies, a set of trial responses for the spectrometer was established and spanned electron energies 0-10 MeV. Measured beta spectra were unfolded for their energy distributions by the program FERD, and then compared to other measurements and summation calculations based on ENDF/B-VI fission-product data performed on the LANL Cray computer. Measurements of the beta activity as a function of decay time furnished a relative normalization. Results for the beta decay heat are presented and compared with other experimental data and the summation calculations.

  11. Fission cross section of 239Th and 232Th relative to 235U

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Meadows, J. W.

    1979-01-01

    The fission cross sections of /sup 230/Th and /sup 232/Th were measured relative to /sup 235/U from near threshold to near 10 MeV. The weights of the thorium samples were determined by isotopic dilution. The weight of the uranium deposit was based on specific activity measurements of a /sup 234/U-/sup 235/U mixture and low geometry alpha counting. Corrections were made for thermal background, loss of fragments in the deposits, neutron scattering in the detector assembly, sample geometry, sample composition and the spectrum of the neutron source. Generally the systematic errors were approx. 1%. The combined systematic and statistical errors weremore » typically 1.5%. 17 references.« less

  12. Improvement of voltage holding capability in the 500 keV negative ion source for JT-60SA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tanaka, Y.; Hanada, M.; Kojima, A.

    2010-02-15

    Voltage holding capability of JT-60 negative ion source that has a large electrostatic negative ion accelerator with 45 cmx1.1 m acceleration grids was experimentally examined and improved to realize 500 keV, 22 A, and 100 s D{sup -} ion beams for JT-60 Super Advanced. The gap lengths in the acceleration stages were extended to reduce electric fields in a gap between the large grids and at the corner of the support flanges from the original 4-5 to 3-4 kV/mm. As a result, the voltage holding capability without beam acceleration has been successfully improved from 400 to 500 kV. The pulsemore » duration to hold 500 kV reached 40 s of the power supply limitation.« less

  13. Application of the 226Ra– 230Th– 234U and 227Ac– 231Pa– 235U radiochronometers to uranium certified reference materials

    DOE PAGES

    Rolison, John M.; Treinen, Kerri C.; McHugh, Kelly C.; ...

    2017-11-06

    Uranium certified reference materials (CRM) issued by New Brunswick Laboratory were subjected to dating using four independent uranium-series radiochronometers. In all cases, there was acceptable agreement between the model ages calculated using the 231Pa– 235U, 230Th– 234U, 227Ac– 235U or 226Ra– 234U radiochronometers and either the certified 230Th– 234U model date (CRM 125-A and CRM U630), or the known purification date (CRM U050 and CRM U100). Finally, the agreement between the four independent radiochronometers establishes these uranium certified reference materials as ideal informal standards for validating dating techniques utilized in nuclear forensic investigations in the absence of standards with certifiedmore » model ages for multiple radiochronometers.« less

  14. Application of the 226Ra– 230Th– 234U and 227Ac– 231Pa– 235U radiochronometers to uranium certified reference materials

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rolison, John M.; Treinen, Kerri C.; McHugh, Kelly C.

    Uranium certified reference materials (CRM) issued by New Brunswick Laboratory were subjected to dating using four independent uranium-series radiochronometers. In all cases, there was acceptable agreement between the model ages calculated using the 231Pa– 235U, 230Th– 234U, 227Ac– 235U or 226Ra– 234U radiochronometers and either the certified 230Th– 234U model date (CRM 125-A and CRM U630), or the known purification date (CRM U050 and CRM U100). Finally, the agreement between the four independent radiochronometers establishes these uranium certified reference materials as ideal informal standards for validating dating techniques utilized in nuclear forensic investigations in the absence of standards with certifiedmore » model ages for multiple radiochronometers.« less

  15. Search for Nuclear Excitation by Electronic Transition in U-235

    NASA Astrophysics Data System (ADS)

    Chodash, P. A.; Norman, E. B.; Burke, J. T.; Wilks, S. C.; Casperson, R. J.; Swanberg, E. L.; Wakeling, M. A.; Cordeiro, T. J.

    2013-10-01

    Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is predicted to occur in numerous isotopes, including U-235. When a nuclear transition matches the energy and the multipolarity of an electronic transition, there is a possibility that NEET will occur. If NEET were to occur in U-235, the nucleus would be excited to its 1/2 + isomeric state that subsequently decays by internal conversion with a decay energy of 77 eV and a half-life of 26 minutes. Theory predicts that NEET can occur in partially ionized uranium plasma with a charge state of 23 +. A pulsed Nd:YAG laser operating at 1064 nm with a pulse energy of 780 mJ and a pulse width of 9 ns was used to generate the uranium plasma. The plasma was collected on a plate and the internal conversion electrons were focused onto a microchannel plate detector by a series of electrostatic lenses. Depleted uranium and highly enriched uranium samples were used for the experiment. Preliminary results will be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. This work was further supported by the U.S. DHS, UC Berkeley, and the NNIS Fellowship.

  16. 206Pb-230Th-234U-238U and 207Pb-235U geochronology of Quaternary opal, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Neymark, Leonid A.; Amelin, Yuri V.; Paces, James B.

    2000-01-01

    U–Th–Pb isotopic systems have been studied in submillimeter-thick outermost layers of Quaternary opal occurring in calcite–silica fracture and cavity coatings within Tertiary tuffs at Yucca Mountain, Nevada, USA. These coatings preserve a record of paleohydrologic conditions at this site, which is being evaluated as a potential high-level nuclear waste repository. The opal precipitated from groundwater is variably enriched in 234U (measured 234U/238U activity ratio 1.124–6.179) and has high U (30–313 ppm), low Th (0.008–3.7 ppm), and low common Pb concentrations (measured 206Pb/204Pb up to 11,370). It has been demonstrated that the laboratory acid treatment used in this study to clean sample surfaces and to remove adherent calcite, did not disturb U–Th–Pb isotopic systems in opal. The opal ages calculated from 206Pb∗/238U and 207Pb∗/235U ratios display strong reverse discordance because of excess radiogenic 206Pb∗ derived from the elevated initial 234U. The data are best interpreted using projections of a new four-dimensional concordia diagram defined by 206Pb∗/238U, 207Pb∗/235U, 234U/238Uactivity, and 230Th/238Uactivity. Ages and initial 234U/238U activity ratios have been calculated using different projections of this diagram and tested for concordance. The data are discordant, that is observed 207Pb∗/235U ages of 170 ± 32 (2σ) to 1772 ± 40 ka are systematically older than 230Th/U ages of 34.1 ± 0.6 to 452 ± 32 ka. The age discordance is not a result of migration of uranium and its decay products under the open system conditions, but a consequence of noninstantaneous growth of opal. Combined U–Pb and 230Th/U ages support the model of slow mineral deposition at the rates of millimeters per million years resulting in layering on a scale too fine for mechanical sampling. In this case, U–Pb ages provide more accurate estimates of the average age for mixed multiage samples than 230Th/U ages, because ages based on shorter

  17. Nuclear Resonance Fluorescence Response of U-235

    NASA Astrophysics Data System (ADS)

    Warren, Glen

    2008-05-01

    Nuclear resonance fluorescence (NRF) is a physical process that provides an isotopic-specific signature that could be used for the identification and characterization of materials. The technique involves the detection of prompt discrete-energy photons emitted from a sample, which is exposed to photons in the MeV energy range. Potential applications of the technique range from detection of high explosives to characterization of special nuclear materials. Pacific Northwest National Laboratory and Passport Systems have collaboratively conducted a set of measurements to search for an NRF response of U-235 in the 1.5 to 9 MeV energy range. Results from these measurements will be presented.

  18. Evaluation of Uranium-235 Measurement Techniques

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kaspar, Tiffany C.; Lavender, Curt A.; Dibert, Mark W.

    2017-05-23

    Monolithic U-Mo fuel plates are rolled to final fuel element form from the original cast ingot, and thus any inhomogeneities in 235U distribution present in the cast ingot are maintained, and potentially exaggerated, in the final fuel foil. The tolerance for inhomogeneities in the 235U concentration in the final fuel element foil is very low. A near-real-time, nondestructive technique to evaluate the 235U distribution in the cast ingot is required in order to provide feedback to the casting process. Based on the technical analysis herein, gamma spectroscopy has been recommended to provide a near-real-time measure of the 235U distribution inmore » U-Mo cast plates.« less

  19. Relative intensities of 2. 5 and 14-MeV source neutrons from comparative responses of U-235 and U-238 detectors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jassby, D.L.; Hendel, H.W.; Bosch, H.S.

    1988-05-01

    The response of polyethylene-moderated U-235 fission counters is only weakly dependent on incident neutron energy, while the response of unmoderated U-238 or Th-232 fission counters increases strongly with energy. A given concentration of D-T neutrons in a mixed DT-DD source results in a unique relative detector response that depends on the parameters R14 and R2.5, where R14 is the ratio of the unmoderated U-238 and moderated U-235 detector efficiencies for a pure 14-MeV neutron source, and R2.5 is the corresponding ratio for a pure 2.5 MeV source. We have determined R14 and R2.5 using D-D and D-T neutron generators insidemore » the TFTR vacuum vessel. The results indicate that, for our detector geometry, the ratio of U-238 to U-235 count rates should increase by a factor of about 3 when the fusion neutron source changes from pure D-D to pure D-T. This calibration is being applied to recent TFTR /open quotes/supershot/close quotes/ data, where the uncollided neutron flux in the post-beam phase contains a high proportion of D-T neutrons from the burnup of D-D tritons. 8 refs., 4 figs,. 2 tabs.« less

  20. Development and evaluation of a collection apparatus for recoil products for study of the deexcitation process of (235m)U.

    PubMed

    Shigekawa, Y; Kasamatsu, Y; Shinohara, A

    2016-05-01

    The nucleus (235m)U is an isomer with extremely low excitation energy (76.8 eV) and decays dominantly through the internal conversion (IC) process. Because outer-shell electrons are involved in the IC process, the decay constant of (235m)U depends on its chemical environment. We plan to study the deexcitation process of (235m)U by measuring the energy spectra of IC electrons in addition to the decay constants for various chemical forms. In this paper, the preparation method of (235m)U samples from (239)Pu by using alpha-recoil energy is reported. A Collection Apparatus for Recoil Products was fabricated, and then collection efficiencies under various conditions were determined by collecting (224)Ra recoiling out of (228)Th electrodeposited and precipitated sources. The pressure in the apparatus (vacuum or 1 atm of N2 gas) affected the variations of the collection efficiencies depending on the negative voltage applied to the collector. The maximum values of the collection efficiencies were mainly affected by the thickness of the (228)Th sources. From these results, the suitable conditions of the (239)Pu sources for preparation of (235m)U were determined. In addition, dissolution efficiencies were determined by washing collected (224)Ra with solutions. When (224)Ra was collected in 1 atm of N2 gas and dissolved with polar solutions such as water, the dissolution efficiencies were nearly 100%. The method of rapid dissolution of recoil products would be applicable to rapid preparation of short-lived (235m)U samples for various chemical forms.

  1. Investigating Uranium Mobility Using Stable Isotope Partitioning of 238U/235U and a Reactive Transport Model

    NASA Astrophysics Data System (ADS)

    Bizjack, M.; Johnson, T. M.; Druhan, J. L.; Shiel, A. E.

    2015-12-01

    We report a numerical reactive transport model which explicitly incorporates the effectively stable isotopes of uranium (U) and the factors that influence their partitioning in bioactive systems. The model reproduces trends observed in U isotope ratios and concentration measurements from a field experiment, thereby improving interpretations of U isotope ratios as a tracer for U reactive transport. A major factor contributing to U storage and transport is its redox state, which is commonly influenced by the availability of organic carbon to support metal-reducing microbial communities. Both laboratory and field experiments have demonstrated that biogenic reduction of U(VI) fractionates the stable isotope ratio 238U/235U, producing an isotopically heavy solid U(IV) product. It has also been shown that other common reactive transport processes involving U do not fractionate isotopes to a consistently measurable level, which suggests the capacity to quantify the extent of bioreduction occurring in groundwater containing U using 238U/235U ratios. A recent study of a U bioremediation experiment at the Rifle IFRC site (Colorado, USA) applied Rayleigh distillation models to quantify U stable isotope fractionation observed during acetate amendment. The application of these simplified models were fit to the observations only by invoking a "memory-effect," or a constant source of low-concentration, unfractionated U(VI). In order to more accurately interpret the measured U isotope ratios, we present a multi-component reactive transport model using the CrunchTope software. This approach is capable of quantifying the cycling and partitioning of individual U isotopes through a realistic network of transport and reaction pathways including reduction, oxidation, and microbial growth. The model incorporates physical heterogeneity of the aquifer sediments through zones of decreased permeability, which replicate the observed bromide tracer, major ion chemistry, U concentration, and U

  2. Measurement of the ^235mU Production Cross Section Using a Critical Assembly*

    NASA Astrophysics Data System (ADS)

    Macri, Robert; Authier, Nicolas; Becker, John; Belier, Gilbert; Bond, Evelyn; Bredeweg, Todd; Glover, S.; Meot, Vincent; Rundberg, Robert; Vieira, David; Wilhelmy, Jerry

    2006-10-01

    Measurements of the creation and destruction cross sections for actinide nuclei constitute an important experimental effort in support of Stockpile Stewardship. In this talk I will give a progress report on the effort to measure the production cross section of the ^235mU isomer integrated over a fission neutron spectrum. This ongoing experiment is fielded at CEA in Valduc, France, taking advantage of the CALIBAN critical assembly. This effort is performed in collaboration with LANL, LLNL, Bruyeres le Chatel, and Valduc staff. This experiment utilizes a technique to measure internal conversion electrons from the ^235mU isomer with the French BIII detector (Bruyeres le Chatel), and involves a substantial chemistry effort (LANL) to prepare targets for irradiation and counting, as well as to remove fission fragments after irradiation. Experimental techniques will be discussed and preliminary data presented. *Work performed under the auspices of the U.S. Department of Energy by Los Alamos National Laboratory (W-7405-ENG-36) and Lawrence Livermore National Laboratory (W-7405-ENG-48), and CEA-DAM under CEA-DAM NNSA-DOE agreement.

  3. Searching for U-235m produced by Nuclear Excitation by Electronic Transition

    NASA Astrophysics Data System (ADS)

    Chodash, Perry; Norman, Eric; Burke, Jason; Wilks, Scott; Casperson, Robert

    2014-09-01

    Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is predicted to occur in numerous isotopes, including U-235. When a nuclear transition matches the energy and the multipolarity of an electronic transition, there is a possibility that NEET will occur. If NEET were to occur in U-235, the nucleus would be excited to its 1/2 + isomeric state that subsequently decays by internal conversion with a decay energy of 77 eV and a half-life of 26 minutes. Theory predicts that NEET can occur in partially ionized uranium plasma with a charge state of 23 +. A pulsed Nd:YAG laser operating at 1064 nm with a pulse energy of 780 mJ and a pulse width of 9 ns was used to generate the uranium plasma. The laser was focused on small samples of both depleted uranium and highly enriched uranium. The plasma conditions created by the intense laser pulse were varied by changing the spot size of the laser on the target. The resulting plasma was collected on a plate and the internal conversion electrons were focused onto a microchannel plate detector by a series of electrostatic lenses. First results will be presented. Nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that is predicted to occur in numerous isotopes, including U-235. When a nuclear transition matches the energy and the multipolarity of an electronic transition, there is a possibility that NEET will occur. If NEET were to occur in U-235, the nucleus would be excited to its 1/2 + isomeric state that subsequently decays by internal conversion with a decay energy of 77 eV and a half-life of 26 minutes. Theory predicts that NEET can occur in partially ionized uranium plasma with a charge state of 23 +. A pulsed Nd:YAG laser operating at 1064 nm with a pulse energy of 780 mJ and a pulse width of 9 ns was used to generate the uranium plasma. The laser was focused on small samples of both depleted uranium and highly enriched uranium. The plasma conditions created by the

  4. Mass Yields and Average Total Kinetic Energy Release in Fission for 235U, 238U, and 239Pu

    NASA Astrophysics Data System (ADS)

    Duke, Dana

    2015-10-01

    Mass yield distributions and average total kinetic energy (TKE) in neutron induced fission of 235U, 238U, and 239Pu targets were measured with a gridded ionization chamber. Despite decades of fission research, our understanding of how fragment mass yields and TKE depend on incident neutron energy is limited, especially at higher energies (above 5-10 MeV). Improved accuracy in these quantities is important for nuclear technology as it enhances our simulation capabilities and increases the confidence in diagnostic tools. The data can also guide and validate theoretical fission models where the correlation between the fragment mass and TKE is of particular value for constraining models. The Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE - WNR) provides a neutron beam with energies from thermal to hundreds of MeV, well-suited for filling in the gaps in existing data and exploring fission behavior in the fast neutron region. The results of the studies on target nuclei 235U, 238U, and 239Pu will be presented with a focus on exploring data trends as a function of neutron energy from thermal through 30 MeV. Results indicate clear evidence of structure due to multi-chance fission in the TKE . LA-UR-15-24761.

  5. A new method to measure the U-235 content in fresh LWR fuel assemblies via fast-neutron passive self-interrogation

    DOE PAGES

    Menlove, Howard Olsen; Belian, Anthony P.; Geist, William H.; ...

    2017-10-07

    The purpose of this paper is to provide a solution to a decades old safeguards problem in the verification of the fissile concentration in fresh light water reactor (LWR) fuel assemblies. The problem is that the burnable poison (e.g. Gd 2O 3) addition to the fuel rods decreases the active neutron assay for the fuel assemblies. This paper presents a new innovative method for the verification of the 235U linear mass density in fresh LEU fuel assemblies that is insensitive to the burnable poison content. The technique makes use of the 238U atoms in the fuel rods to self-interrogate themore » 235U mass. The innovation for the new approach is that the 238U spontaneous fission (SF) neutrons from the rods induces fission reactions (IF) in the 235U that are time correlated with the SF source neutrons. Thus, the coincidence gate counting rate benefits from both the nu-bar of the 238U SF (2.07) and the 235U IF (2.44) for a fraction of the IF reactions. Whereas, the 238U SF background has no time-correlation boost. The higher the detection efficiency, the higher the correlated boost because background neutron counts from the SF are being converted to signal doubles. This time-correlation in the IF signal increases signal/background ratio that provides a good precision for the net signal from the 235U mass. The hard neutron energy spectrum makes the technique insensitive to the burnable poison loading where a Cd or Gd liner on the detector walls is used to prevent thermal-neutron reflection back into the fuel assembly from the detector. Here, we have named the system the fast-neutron passive collar (FNPC).« less

  6. A new method to measure the U-235 content in fresh LWR fuel assemblies via fast-neutron passive self-interrogation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Menlove, Howard Olsen; Belian, Anthony P.; Geist, William H.

    The purpose of this paper is to provide a solution to a decades old safeguards problem in the verification of the fissile concentration in fresh light water reactor (LWR) fuel assemblies. The problem is that the burnable poison (e.g. Gd 2O 3) addition to the fuel rods decreases the active neutron assay for the fuel assemblies. This paper presents a new innovative method for the verification of the 235U linear mass density in fresh LEU fuel assemblies that is insensitive to the burnable poison content. The technique makes use of the 238U atoms in the fuel rods to self-interrogate themore » 235U mass. The innovation for the new approach is that the 238U spontaneous fission (SF) neutrons from the rods induces fission reactions (IF) in the 235U that are time correlated with the SF source neutrons. Thus, the coincidence gate counting rate benefits from both the nu-bar of the 238U SF (2.07) and the 235U IF (2.44) for a fraction of the IF reactions. Whereas, the 238U SF background has no time-correlation boost. The higher the detection efficiency, the higher the correlated boost because background neutron counts from the SF are being converted to signal doubles. This time-correlation in the IF signal increases signal/background ratio that provides a good precision for the net signal from the 235U mass. The hard neutron energy spectrum makes the technique insensitive to the burnable poison loading where a Cd or Gd liner on the detector walls is used to prevent thermal-neutron reflection back into the fuel assembly from the detector. Here, we have named the system the fast-neutron passive collar (FNPC).« less

  7. A new method to measure the U-235 content in fresh LWR fuel assemblies via fast-neutron passive self-interrogation

    NASA Astrophysics Data System (ADS)

    Menlove, Howard; Belian, Anthony; Geist, William; Rael, Carlos

    2018-01-01

    The purpose of this paper is to provide a solution to a decades old safeguards problem in the verification of the fissile concentration in fresh light water reactor (LWR) fuel assemblies. The problem is that the burnable poison (e.g. Gd2O3) addition to the fuel rods decreases the active neutron assay for the fuel assemblies. This paper presents a new innovative method for the verification of the 235U linear mass density in fresh LEU fuel assemblies that is insensitive to the burnable poison content. The technique makes use of the 238U atoms in the fuel rods to self-interrogate the 235U mass. The innovation for the new approach is that the 238U spontaneous fission (SF) neutrons from the rods induces fission reactions (IF) in the 235U that are time correlated with the SF source neutrons. Thus, the coincidence gate counting rate benefits from both the nu-bar of the 238U SF (2.07) and the 235U IF (2.44) for a fraction of the IF reactions. Whereas, the 238U SF background has no time-correlation boost. The higher the detection efficiency, the higher the correlated boost because background neutron counts from the SF are being converted to signal doubles. This time-correlation in the IF signal increases signal/background ratio that provides a good precision for the net signal from the 235U mass. The hard neutron energy spectrum makes the technique insensitive to the burnable poison loading where a Cd or Gd liner on the detector walls is used to prevent thermal-neutron reflection back into the fuel assembly from the detector. We have named the system the fast-neutron passive collar (FNPC).

  8. Acceleration of 500 keV Negative Ion Beams By Tuning Vacuum Insulation Distance On JT-60 Negative Ion Source

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kojima, A.; Hanada, M.; Tanaka, Y.

    2011-09-26

    Acceleration of a 500 keV beam up to 2.8 A has been achieved on a JT-60U negative ion source with a three-stage accelerator by overcoming low voltage holding which is one of the critical issues for realization of the JT-60SA ion source. In order to improve the voltage holding, preliminary voltage holding tests with small-size grids with uniform and locally intense electric fields were carried out, and suggested that the voltage holding was degraded by both the size and local electric field effects. Therefore, the local electric field was reduced by tuning gap lengths between the large size grids andmore » grid support structures of the accelerator. Moreover, a beam radiation shield which limited extension of the minimum gap length was also optimized so as to reduce the local electric field while maintaining the shielding effect. These modifications were based on the experiment results, and significantly increased the voltage holding from <150 kV/stage for the original configuration to 200 kV/stage. These techniques for improvement of voltage holding should also be applicable to other large ion sources accelerators such as those for ITER.« less

  9. Reactive transport of uranium in a groundwater bioreduction study: Insights from high-temporal resolution 238U/235U data

    NASA Astrophysics Data System (ADS)

    Shiel, A. E.; Johnson, T. M.; Lundstrom, C. C.; Laubach, P. G.; Long, P. E.; Williams, K. H.

    2016-08-01

    We conducted a detailed investigation of U isotopes in conjunction with a broad geochemical investigation during field-scale biostimulation and desorption experiments. This investigation was carried out in the uranium-contaminated alluvial aquifer of the Rifle field research site. In this well-characterized setting, a more comprehensive understanding of U isotope geochemistry is possible. Our results indicate that U isotope fractionation is consistently observed across multiple experiments at the Rifle site. Microbially-mediated reduction is suggested to account for most or all of the observed fractionation as abiotic reduction has been demonstrated to impart much smaller, often near-zero, isotopic fractionation or isotopic fractionation in the opposite direction. Data from some time intervals are consistent with a simple model for transport and U(VI) reduction, where the fractionation factor (ε = +0.65‰ to +0.85‰) is consistent with experimental studies. However, during other time intervals the observed patterns in our data indicate the importance of other processes in governing U concentrations and 238U/235U ratios. For instance, we demonstrate that departures from Rayleigh behavior in groundwater systems arise from the presence of adsorbed species. We also show that isotope data are sensitive to the onset of oxidation after biostimulation ends, even in the case where reduction continues to remove contaminant uranium downstream. Our study and the described conceptual model support the use of 238U/235U ratios as a tool for evaluating the efficacy of biostimulation and potentially other remedial strategies employed at Rifle and other uranium-contaminated sites.

  10. Benchmark experiments at ASTRA facility on definition of space distribution of {sup 235}U fission reaction rate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bobrov, A. A.; Boyarinov, V. F.; Glushkov, A. E.

    2012-07-01

    Results of critical experiments performed at five ASTRA facility configurations modeling the high-temperature helium-cooled graphite-moderated reactors are presented. Results of experiments on definition of space distribution of {sup 235}U fission reaction rate performed at four from these five configurations are presented more detail. Analysis of available information showed that all experiments on criticality at these five configurations are acceptable for use them as critical benchmark experiments. All experiments on definition of space distribution of {sup 235}U fission reaction rate are acceptable for use them as physical benchmark experiments. (authors)

  11. Evaluated Mean Values and Covariances for the Prompt Fission Neutron Spectrum of 239Pu induced by neutrons of 500 keV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Neudecker, Denise

    2014-07-10

    This document provides the numerical values of the evaluated prompt fission neutron spectrum for 239Pu induced by neutrons of 500 keV as well as relative uncertainties and correlations. This document also contains a short description how these data were obtained and shows plots comparing the evaluated results to experimental information as well as the corresponding ENDF/B-VII.1 evaluation.

  12. Effects of combined irradiation of 500 keV protons and atomic oxygen on polyimide films

    NASA Astrophysics Data System (ADS)

    Novikov, Lev; Chernik, Vladimir; Zhilyakov, Lev; Voronina, Ekaterina; Chirskaia, Natalia

    2016-07-01

    Polyimide films are widely used on the spacecraft surface as thermal control coating, films in different constuctions, etc. However, the space ionizing radiation of different types can alter the mechanical, optical and electrical properties of polyimide films. For example, it is well known that 20-100 keV proton irradiation causes breaking of chemical bonds and destruction of the surface layer in polyimide, deterioration of its optical properties, etc. In low-Earth orbits serious danger for polymeric materials is atomic oxygen of the upper atmosphere of the Earth, which is the main component in the range of heights of 200-800 km. Due to the orbital spacecraft velocity, the collision energy of oxygen atoms with the surface ( 5 eV) enhances their reactivity and opens additional pathways of their reaction with near-surface layers of materials. Hyperthermal oxygen atom flow causes erosion of the polyimide surface by breaking chemical bonds and forming of volatiles products (primarily, CO and CO _{2}), which leads to mass losses and degradation of material properties. Combined effect of protons and oxygen plasma is expected to give rise to synergistic effects enhancing the destruction of polyimide surface layers. This paper describes experimental investigation of polyimide films sequential irradiation with protons and oxygen plasma. The samples were irradiated by 500 keV protons at fluences of 10 ^{14}-10 ^{16} cm ^{-2} produced with SINP cascade generator KG-500 and 5-20 eV neutral oxygen atoms at fluence of 10 ^{20} cm ^{-2} generated by SINP magnetoplasmodynamics accelerator. The proton bombardment causes the decrease in optical transmission coefficient of samples, but their transmittance recovers partially after the exposure to oxygen plasma. The results of the comparative analysis of polyimide optical transmission spectra, Raman and XPS spectra obtained at different stages of the irradiation of samples, data on mass loss of samples due to erosion of the surface are

  13. Ground water contamination with (238)U, (234)U, (235)U, (226)Ra and (210)Pb from past uranium mining: cove wash, Arizona.

    PubMed

    Dias da Cunha, Kenya Moore; Henderson, Helenes; Thomson, Bruce M; Hecht, Adam A

    2014-06-01

    The objectives of the study are to present a critical review of the (238)U, (234)U, (235)U, (226)Ra and (210)Pb levels in water samples from the EPA studies (U.S. EPA in Abandoned uranium mines and the Navajo Nation: Red Valley chapter screening assessment report. Region 9 Superfund Program, San Francisco, 2004, Abandoned uranium mines and the Navajo Nation: Northern aum region screening assessment report. Region 9 Superfund Program, San Francisco, 2006, Health and environmental impacts of uranium contamination, 5-year plan. Region 9 Superfund Program, San Franciso, 2008) and the dose assessment for the population due to ingestion of water containing (238)U and (234)U. The water quality data were taken from Sect. "Data analysis" of the published report, titled Abandoned Uranium Mines Project Arizona, New Mexico, Utah-Navajo Lands 1994-2000, Project Atlas. Total uranium concentration was above the maximum concentration level for drinking water (7.410-1 Bq/L) in 19 % of the water samples, while (238)U and (234)U concentrations were above in 14 and 17 % of the water samples, respectively. (226)Ra and (210)Pb concentrations in water samples were in the range of 3.7 × 10(-1) to 5.55 × 102 Bq/L and 1.11 to 4.33 × 102 Bq/L, respectively. For only two samples, the (226)Ra concentrations exceeded the MCL for total Ra for drinking water (0.185 Bq/L). However, the (210)Pb/(226)Ra ratios varied from 0.11 to 47.00, and ratios above 1.00 were observed in 71 % of the samples. Secular equilibrium of the natural uranium series was not observed in the data record for most of the water samples. Moreover, the (235)U/(total)U mass ratios ranged from 0.06 to 5.9 %, and the natural mass ratio of (235)U to (total)U (0.72 %) was observed in only 16 % of the water samples, ratios above or below the natural ratio could not be explained based on data reported by U.S. EPA. In addition, statistical evaluations showed no correlations among the distribution of the radionuclide concentrations

  14. Radiative neutron capture cross section from 236U

    NASA Astrophysics Data System (ADS)

    Baramsai, B.; Jandel, M.; Bredeweg, T. A.; Bond, E. M.; Roman, A. R.; Rusev, G.; Walker, C. L.; Couture, A.; Mosby, S.; O'Donnell, J. M.; Ullmann, J. L.; Kawano, T.

    2017-08-01

    The 236U(n ,γ ) reaction cross section has been measured for the incident neutron energy range from 10 eV to 800 keV by using the Detector for Advanced Neutron Capture Experiments (DANCE) γ -ray calorimeter at the Los Alamos Neutron Science Center. The cross section was determined with the ratio method, which is a technique that uses the 235U(n ,f ) reaction as a reference. The results of the experiment are reported in the resolved and unresolved resonance energy regions. Individual neutron resonance parameters were obtained below 1 keV incident energy by using the R -matrix code sammy. The cross section in the unresolved resonance region is determined with improved experimental uncertainty. It agrees with both ENDF/B-VII.1 and JEFF-3.2 nuclear data libraries. The results above 10 keV agree better with the JEFF-3.2 library.

  15. The 235U Prompt Fission Neutron Spectrum in the BR1 Reactor at SCK•CEN

    NASA Astrophysics Data System (ADS)

    Wagemans, Jan; Malambu, Edouard; Borms, Luc; Fiorito, Luca

    2016-02-01

    The BR1 research reactor at SCK•CEN has a spherical cavity in the graphite above the reactor core. In this cavity an accurately characterised Maxwellian thermal neutron field is present. Different converters can be loaded in the cavity in order to obtain other types of neutron (and gamma) irradiation fields. Inside the so-called MARK III converter a fast 235U(n,f) prompt fission neutron field can be obtained. With the support of MCNP calculations, irradiations in MARK III can be directly related to the pure 235U(n,f) prompt fission neutron spectrum. For this purpose MARK III spectrum averaged cross sections for the most relevant fluence dosimetry reactions have been determined. A calibration factor for absolute measurements has been determined applying activation dosimetry following ISO/IEC 17025 standards.

  16. Measurement of the 234U(n, f ) cross-section with quasi-monoenergetic beams in the keV and MeV range using a Micromegas detector assembly

    NASA Astrophysics Data System (ADS)

    Stamatopoulos, A.; Kanellakopoulos, A.; Kalamara, A.; Diakaki, M.; Tsinganis, A.; Kokkoris, M.; Michalopoulou, V.; Axiotis, M.; Lagoyiannis, A.; Vlastou, R.

    2018-01-01

    The 234U neutron-induced fission cross-section has been measured at incident neutron energies of 452, 550, 651 keV and 7.5, 8.7, 10 MeV using the 7Li ( p, n) and the 2H( d, n) reactions, respectively, relative to the 235U( n, f ) and 238U( n, f ) reference reactions. The measurement was performed at the neutron beam facility of the National Center for Scientific Research "Demokritos", using a set-up based on Micromegas detectors. The active mass of the actinide samples and the corresponding impurities were determined via α-spectroscopy using a surface barrier silicon detector. The neutron spectra intercepted by the actinide samples have been thoroughly studied by coupling the NeuSDesc and MCNP5 codes, taking into account the energy and angular straggling of the primary ion beams in the neutron source targets in addition to contributions from competing reactions ( e.g. deuteron break-up) and neutron scattering in the surrounding materials. Auxiliary Monte Carlo simulations were performed making combined use of the FLUKA and GEF codes, focusing particularly on the determination of the fission fragment detection efficiency. The developed methodology and the final results are presented.

  17. Method for radioactivity monitoring

    DOEpatents

    Umbarger, C. John; Cowder, Leo R.

    1976-10-26

    The disclosure relates to a method for analyzing uranium and/or thorium contents of liquid effluents preferably utilizing a sample containing counting chamber. Basically, 185.7-keV gamma rays following .sup.235 U alpha decay to .sup.231 Th which indicate .sup.235 U content and a 63-keV gamma ray doublet found in the nucleus of .sup.234 Pa, a granddaughter of .sup.238 U, are monitored and the ratio thereof taken to derive uranium content and isotopic enrichment .sup.235 U/.sup.235 U + .sup.238 U) in the liquid effluent. Thorium content is determined by monitoring the intensity of 238-keV gamma rays from the nucleus of .sup.212 Bi in the decay chain of .sup.232 Th.

  18. Exploratory study of fission product yields of neutron-induced fission of 235U , 238U , and 239Pu at 8.9 MeV

    NASA Astrophysics Data System (ADS)

    Bhatia, C.; Fallin, B. F.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.; Arnold, C. W.; Bond, E.; Bredeweg, T. A.; Fowler, M. M.; Moody, W.; Rundberg, R. S.; Rusev, G. Y.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Macri, R.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.

    2015-06-01

    Using dual-fission chambers each loaded with a thick (200 -400 -mg /c m2) actinide target of 235 ,238U or 239Pu and two thin (˜10 -100 -μ g /c m2) reference foils of the same actinide, the cumulative yields of fission products ranging from 92Sr to 147Nd have been measured at En= 8.9 MeV . The 2H(d ,n ) 3He reaction provided the quasimonoenergetic neutron beam. The experimental setup and methods used to determine the fission product yield (FPY) are described, and results for typically eight high-yield fission products are presented. Our FPYs for 235U(n ,f ) , 238U(n ,f ) , and 239Pu(n ,f ) at 8.9 MeV are compared with the existing data below 8 MeV from Glendenin et al. [Phys. Rev. C 24, 2600 (1981), 10.1103/PhysRevC.24.2600], Nagy et al. [Phys. Rev. C 17, 163 (1978), 10.1103/PhysRevC.17.163], Gindler et al. [Phys. Rev. C 27, 2058 (1983), 10.1103/PhysRevC.27.2058], and those of Mac Innes et al. [Nucl. Data Sheets 112, 3135 (2011), 10.1016/j.nds.2011.11.009] and Laurec et al. [Nucl. Data Sheets 111, 2965 (2010), 10.1016/j.nds.2010.11.004] at 14.5 and 14.7 MeV, respectively. This comparison indicates a negative slope for the energy dependence of most fission product yields obtained from 235U and 239Pu , whereas for 238U the slope issue remains unsettled.

  19. Fission Product Yield Study of 235U, 238U and 239Pu Using Dual-Fission Ionization Chambers

    NASA Astrophysics Data System (ADS)

    Bhatia, C.; Fallin, B.; Howell, C.; Tornow, W.; Gooden, M.; Kelley, J.; Arnold, C.; Bond, E.; Bredeweg, T.; Fowler, M.; Moody, W.; Rundberg, R.; Rusev, G.; Vieira, D.; Wilhelmy, J.; Becker, J.; Macri, R.; Ryan, C.; Sheets, S.; Stoyer, M.; Tonchev, A.

    2014-05-01

    To resolve long-standing differences between LANL and LLNL regarding the correct fission basis for analysis of nuclear test data [M.B. Chadwick et al., Nucl. Data Sheets 111, 2891 (2010); H. Selby et al., Nucl. Data Sheets 111, 2891 (2010)], a collaboration between TUNL/LANL/LLNL has been established to perform high-precision measurements of neutron induced fission product yields. The main goal is to make a definitive statement about the energy dependence of the fission yields to an accuracy better than 2-3% between 1 and 15 MeV, where experimental data are very scarce. At TUNL, we have completed the design, fabrication and testing of three dual-fission chambers dedicated to 235U, 238U, and 239Pu. The dual-fission chambers were used to make measurements of the fission product activity relative to the total fission rate, as well as for high-precision absolute fission yield measurements. The activation method was employed, utilizing the mono-energetic neutron beams available at TUNL. Neutrons of 4.6, 9.0, and 14.5 MeV were produced via the 2H(d,n)3He reaction, and for neutrons at 14.8 MeV, the 3H(d,n)4He reaction was used. After activation, the induced γ-ray activity of the fission products was measured for two months using high-resolution HPGe detectors in a low-background environment. Results for the yield of seven fission fragments of 235U, 238U, and 239Pu and a comparison to available data at other energies are reported. For the first time results are available for neutron energies between 2 and 14 MeV.

  20. n+235U resonance parameters and neutron multiplicities in the energy region below 100 eV

    NASA Astrophysics Data System (ADS)

    Pigni, Marco T.; Capote, Roberto; Trkov, Andrej; Pronyaev, Vladimir G.

    2017-09-01

    In August 2016, following the recent effort within the Collaborative International Evaluated Library Organization (CIELO) pilot project to improve the neutron cross sections of 235U, Oak Ridge National Laboratory (ORNL) collaborated with the International Atomic Energy Agency (IAEA) to release a resonance parameter evaluation. This evaluation restores the performance of the evaluated cross sections for the thermal- and above-thermal-solution benchmarks on the basis of newly evaluated thermal neutron constants (TNCs) and thermal prompt fission neutron spectra (PFNS). Performed with support from the US Nuclear Criticality Safety Program (NCSP) in an effort to provide the highest fidelity general purpose nuclear database for nuclear criticality applications, the resonance parameter evaluation was submitted as an ENDF-compatible file to be part of the next release of the ENDF/B-VIII.0 nuclear data library. The resonance parameter evaluation methodology used the Reich-Moore approximation of the R-matrix formalism implemented in the code SAMMY to fit the available time-of-flight (TOF) measured data for the thermal induced cross section of n+235U up to 100 eV. While maintaining reasonably good agreement with the experimental data, the validation analysis focused on restoring the benchmark performance for 235U solutions by combining changes to the resonance parameters and to the prompt resonance v̅

  1. The Prompt Fission Neutron Spectrum of 235U(n,f) below 2.5 MeV for Incident Neutrons from 0.7 to 20 MeV

    NASA Astrophysics Data System (ADS)

    Devlin, M.; Gomez, J. A.; Kelly, K. J.; Haight, R. C.; O'Donnell, J. M.; Taddeucci, T. N.; Lee, H. Y.; Mosby, S. M.; Perdue, B. A.; Fotiades, N.; Ullmann, J. L.; Wu, C. Y.; Bucher, B.; Buckner, M. Q.; Henderson, R. A.; Neudecker, D.; White, M. C.; Talou, P.; Rising, M. E.; Solomon, C. J.

    2018-02-01

    New prompt fission neutron spectrum measurements are reported for 235U(n , f) reactions induced by neutrons with energies from 0.7 to 20 MeV. These measurements cover outgoing neutron energies from 2.5 MeV down to 10 keV, using an array of 6Li-glass scintillators for neutron detection and a double time-of-flight technique. The neutrons were produced at the Weapons Neutron Research facility of the Los Alamos Neutron Science Center. A detailed MCNP® model of the experimental equipment and the surrounding room was used to interpret the experimental results. Backgrounds were measured in situ, making use of the time-dependent singles rates of the various detectors with asynchronous readout from waveform digitizers. The results presented here have been included in a re-evaluation of the fission neutron spectra for this fissioning system, a description of which is presented elsewhere in this issue.

  2. Cost, healthcare resource utilization, and adherence of individuals with diabetes using U-500 or U-100 insulin: a retrospective database analysis.

    PubMed

    Eby, Elizabeth L; Wang, Ping; Curtis, Bradley H; Xie, Jin; Haldane, Diane C; Idris, Iskandar; Peters, Anne L; Hood, Robert C; Jackson, Jeffrey A

    2013-01-01

    To describe costs, healthcare resource utilization, and adherence of US patients receiving human regular U-500 insulin (U-500R), compared to patients receiving high-dose (>200 units/day) U-100 insulins (U-100) by subcutaneous injection for the treatment of diabetes. A retrospective analysis of data from Thomson Reuters MarketScan Research Databases (7/1/2008 to 12/31/2010). Difference-in-differences analyses were conducted on cost (medical, pharmacy, and overall costs) and on healthcare resource utilization variables (overall, diabetes-related, and non-diabetes-related medical visits). Adherence rates to the index insulins were assessed by proportion of days covered (PDC). Seven hundred and eleven (19%) patients in the U-500R cohort and 1508 (6%) patients in the U-100 cohort met selection criteria. Propensity score matching resulted in 684 matched pairs. Mean change in annualized pharmacy costs was in favor of the U-500R vs the U-100 cohort (-$1258 vs $3345, a difference of -$4603, p < 0.0001). Mean overall cost increase in the U-500R vs the U-100 cohort was also lower ($1999 vs $9104, a difference of -$7105, p = 0.005). The proportion of patients with at least one coded hypoglycemic event during the 12-month post-index period was higher in the U-500R vs the U-100 cohort (17.1% vs 11.7%, p < 0.005), but neither hypoglycemia rate (2.73 vs 2.90 events per person) nor hypoglycemia-specific costs (mean $1669 vs $1543) were significantly different. No significant differences were noted between cohorts for change (post-pre) in any resource utilization category. PDC was greater in the U-500R vs the U-100 cohort (65.2% vs 39.5%, p < 0.0001). Claims data are not as accurate as empirical evaluation by a clinician. Glycemic control data were not available for this analysis. In patients requiring high-dose insulin, treatment with U-500R vs high-dose U-100 insulins is associated with significant decreases in pharmacy and overall costs, slightly higher

  3. Prompt neutron emission and energy balance in 235U(n,f)

    NASA Astrophysics Data System (ADS)

    Göök, Alf; Hambsch, Franz-Josef; Oberstedt, Stephan

    2017-09-01

    Investigations of prompt fission neutron (PFN) emission are of importance in understanding the fission process in general and the sharing of excitation energy among the fission fragments in particular. Experimental activities at JRC-Geel on PFN emission in response to OECD/NEA nuclear data requests is presented in this contribution. The focus lies on on-going investigations of PFN emission from the reaction 235U(n,f) in the region of the resolved resonances taking place at the GELINA facility. For this reaction strong fluctuations of fission fragment mass distributions and mean total kinetic energy have been observed as a function of incident neutron energy in the resonance region. In addition, fluctuations of prompt neutron multiplicities have also been observed. The goal of the present study is to verify the current knowledge of PFN multiplicity fluctuations and to study correlations with fission fragment properties. The experiment employs a scintillation detector array for neutron detection, while fission fragment properties are determined via the double kinetic energy technique using a position sensitive twin ionization chamber. Results on PFN multiplicity correlations with fission fragment properties from the present study show significant differences compared to earlier studies on this reaction, induced by thermal neutrons. Specifically, the total kinetic energy dependence of the neutron multiplicity per fission shows an inverse slope FX1TKE/FX2ν approximately 35% weaker than observed in earlier studies of thermal neutron induced fission on 235U. The inverse slope is related to the energy carried away per emitted neutron and is, thereby, closely connected to the energy balance of the fission reaction. The present result should have strong impact on the modeling of both prompt neutron and prompt γ-ray emission in fission of the 236U compound nucleus.

  4. Radial dependence of lineal energy distribution of 290-MeV/u carbon and 500-MeV/u iron ion beams using a wall-less tissue-equivalent proportional counter

    PubMed Central

    Tsuda, Shuichi; Sato, Tatsuhiko; Watanabe, Ritsuko; Takada, Masashi

    2015-01-01

    Using a wall-less tissue-equivalent proportional counter for a 0.72-μm site in tissue, we measured the radial dependence of the lineal energy distribution, yf(y), of 290-MeV/u carbon ions and 500-MeV/u iron ion beams. The measured yf(y) distributions and the dose-mean of y, y¯D, were compared with calculations performed with the track structure simulation code TRACION and the microdosimetric function of the Particle and Heavy Ion Transport code System (PHITS). The values of the measured y¯D were consistent with calculated results within an error of 2%, but differences in the shape of yf(y) were observed for iron ion irradiation. This result indicates that further improvement of the calculation model for yf(y) distribution in PHITS is needed for the analytical function that describes energy deposition by delta rays, particularly for primary ions having linear energy transfer in excess of a few hundred keV μm−1. PMID:25210053

  5. Characterization of bauxite residue (red mud) for 235U, 238U, 232Th and 40K using neutron activation analysis and the radiation dose levels as modeled by MCNP.

    PubMed

    Landsberger, S; Sharp, A; Wang, S; Pontikes, Y; Tkaczyk, A H

    2017-07-01

    This study employs thermal and epithermal neutron activation analysis (NAA) to quantitatively and specifically determine absorption dose rates to various body parts from uranium, thorium and potassium. Specifically, a case study of bauxite residue (red mud) from an industrial facility was used to demonstrate the feasibility of the NAA approach for radiological safety assessment, using small sample sizes to ascertain the activities of 235 U, 238 U, 232 Th and 40 K. This proof-of-concept was shown to produce reliable results and a similar approach could be used for quantitative assessment of other samples with possible radiological significance. 238 U and 232 Th were determined by epithermal and thermal neutron activation analysis, respectively. 235 U was determined based on the known isotopic ratio of 238 U/ 235 U. 40 K was also determined using epithermal neutron activation analysis to measure total potassium content and then subtracting its isotopic contribution. Furthermore, the work demonstrates the application of Monte Carlo Neutral-Particle (MCNP) simulations to estimate the radiation dose from large quantities of red mud, to assure the safety of humans and the surrounding environment. Phantoms were employed to observe the dose distribution throughout the human body demonstrating radiation effects on each individual organ. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. The Prompt Fission Neutron Spectrum of 235U(n,f) below 2.5 MeV for Incident Neutrons from 0.7 to 20 MeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Devlin, Matthew James; Gomez, Jaime A.; Kelly, Keegan John

    New prompt fission neutron spectrum measurements are reported for 235U(n,f) reactions induced by neutrons with energies from 0.7 to 20 MeV. These measurements cover outgoing neutron energies from 2.5 MeV down to 10 keV, using an array of 6Li-glass scintillators for neutron detection and a double time-of-flight technique. The neutrons were produced at the Weapons Neutron Research facility of the Los Alamos Neutron Science Center. A detailed MCNP ® model of the experimental equipment and the surrounding room was used to interpret the experimental results. Backgrounds were measured in situ, making use of the time-dependent singles rates of the variousmore » detectors with asynchronous readout from waveform digitizers. The results presented here have been included in a re-evaluation of the fission neutron spectra for this fissioning system, a description of which is presented elsewhere in this issue.« less

  7. The Prompt Fission Neutron Spectrum of 235U(n,f) below 2.5 MeV for Incident Neutrons from 0.7 to 20 MeV

    DOE PAGES

    Devlin, Matthew James; Gomez, Jaime A.; Kelly, Keegan John; ...

    2018-02-01

    New prompt fission neutron spectrum measurements are reported for 235U(n,f) reactions induced by neutrons with energies from 0.7 to 20 MeV. These measurements cover outgoing neutron energies from 2.5 MeV down to 10 keV, using an array of 6Li-glass scintillators for neutron detection and a double time-of-flight technique. The neutrons were produced at the Weapons Neutron Research facility of the Los Alamos Neutron Science Center. A detailed MCNP ® model of the experimental equipment and the surrounding room was used to interpret the experimental results. Backgrounds were measured in situ, making use of the time-dependent singles rates of the variousmore » detectors with asynchronous readout from waveform digitizers. The results presented here have been included in a re-evaluation of the fission neutron spectra for this fissioning system, a description of which is presented elsewhere in this issue.« less

  8. Fission cross sections of some thorium, uranium, neptunium and plutonium isotopes relative to /sup 235/U

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Meadows, J W

    1983-10-01

    Earlier results from the measurements, at this Laboratory, of the fission cross sections of /sup 230/Th, /sup 232/Th, /sup 233/U, /sup 234/U, /sup 236/U, /sup 238/U, /sup 237/Np, /sup 239/Pu, /sup 240/Pu, and /sup 242/Pu relative to /sup 235/U are reviewed with revisions to include changes in data processing procedures, alpha half lives and thermal fission cross sections. Some new data have also been included. The current experimental methods and procedures and the sample assay methods are described in detail and the sources of error are presented in a systematic manner. 38 references.

  9. The fission cross sections of /sup 230/Th, /sup 232/Th, /sup 233/U, /sup 234/U, /sup 236/U, /sup 238/U, /sup 237/Np, /sup 239/Pu and /sup 242/Pu relative /sup 235/U at 14. 74 MeV neutron energy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Meadows, J.W.

    1986-12-01

    The measurement of the fission cross section ratios of nine isotopes relative to /sup 235/U at an average neutron energy of 14.74 MeV is described with particular attention to the determination of corrections and to sources of error. The results are compared to ENDF/B-V and to other measurements of the past decade. The ratio of the neutron induced fission cross section for these isotopes to the fission cross section for /sup 235/U are: /sup 230/Th - 0.290 +- 1.9%; /sup 232/Th - 0.191 +- 1.9%; /sup 233/U - 1.132 +- 0.7%; /sup 234/U - 0.998 +- 1.0%; /sup 236/U -more » 0.791 +- 1.1%; /sup 238/U - 0.587 +- 1.1%; /sup 237/Np - 1.060 +- 1.4%; /sup 239/Pu - 1.152 +- 1.1%; /sup 242/Pu - 0.967 +- 1.0%. 40 refs., 11 tabs., 9 figs.« less

  10. Trace metal cycling and 238U/235U in New Zealand's fjords: Implications for reconstructing global paleoredox conditions in organic-rich sediments

    NASA Astrophysics Data System (ADS)

    Hinojosa, Jessica L.; Stirling, Claudine H.; Reid, Malcolm R.; Moy, Christopher M.; Wilson, Gary S.

    2016-04-01

    Reconstructing the history of ocean oxygenation provides insight into links between ocean anoxia, biogeochemical cycles, and climate. Certain redox-sensitive elements respond to changes in marine oxygen content through phase shifts and concomitant isotopic fractionation, providing new diagnostic proxies of past ocean hypoxia. Here we explore the behavior and inter-dependence of a suite of commonly utilized redox-sensitive trace metals (U, Mo, Fe, and Mn) and the emerging ;stable; isotope system of U (238U/235U, or δ238U) in New Zealand fjords. These semi-restricted basins have chemical conditions spanning the complete redox spectrum from fully oxygenated to suboxic to intermittently anoxic/euxinic. In the anoxic water column, U and Mo concentrations decrease, while Fe and Mn concentrations increase. Similarly, signals of past euxinic conditions can be found by U, Mo, Fe, and Mn enrichment in the underlying sediments. The expected U isotopic shift toward a lower δ238U in the anoxic water column due to U(VI)-U(IV) reduction is not observed; instead, water column δ238U profiles are consistent in fjords of all oxygen content, falling within previously reported ranges for open ocean seawater (δ238U = -0.42 ± 0.07‰). Additionally, surface sediment δ238U results show evidence for competing U isotope fractionation processes. One site indicates increased export of 238U from seawater to the underlying sediments (fractionation between aqueous seawater U and particulate sediment U, or ΔU(aq)-U(solid) = -0.25‰), consistent with redox-driven fractionation. Another site suggests potential U(VI) adsorption-driven fractionation, reflecting increased export of 235U from seawater to sediments (ΔU(aq)-U(solid) = 0.25‰). We discuss several potential factors that could alter δ238U in waters and sediments beyond redox-driven shifts, including adsorption to organic matter in waters of high primary productivity, reaction rates for competing processes of U adsorption and

  11. 48 CFR 252.235-7002 - Animal welfare.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Animal welfare. 252.235... Clauses 252.235-7002 Animal welfare. As prescribed in 235.072(a), use the following clause: Animal Welfare... animals only from dealers licensed by the Secretary of Agriculture under 7 U.S.C. 2133 and 9 CFR subpart A...

  12. 48 CFR 252.235-7002 - Animal welfare.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Animal welfare. 252.235... Clauses 252.235-7002 Animal welfare. As prescribed in 235.072(a), use the following clause: Animal Welfare... animals only from dealers licensed by the Secretary of Agriculture under 7 U.S.C. 2133 and 9 CFR subpart A...

  13. 48 CFR 252.235-7002 - Animal welfare.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Animal welfare. 252.235... Clauses 252.235-7002 Animal welfare. As prescribed in 235.072(a), use the following clause: Animal Welfare... animals only from dealers licensed by the Secretary of Agriculture under 7 U.S.C. 2133 and 9 CFR subpart A...

  14. 48 CFR 252.235-7002 - Animal welfare.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Animal welfare. 252.235... Clauses 252.235-7002 Animal welfare. As prescribed in 235.072(a), use the following clause: Animal Welfare... animals only from dealers licensed by the Secretary of Agriculture under 7 U.S.C. 2133 and 9 CFR subpart A...

  15. 48 CFR 252.235-7002 - Animal welfare.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Animal welfare. 252.235... Clauses 252.235-7002 Animal welfare. As prescribed in 235.072(a), use the following clause: Animal Welfare... animals only from dealers licensed by the Secretary of Agriculture under 7 U.S.C. 2133 and 9 CFR subpart A...

  16. Active detection of shielded SNM with 60-keV neutrons

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hagmann, C; Dietrich, D; Hall, J

    2008-07-08

    Fissile materials, e.g. {sup 235}U and {sup 239}Pu, can be detected non-invasively by active neutron interrogation. A unique characteristic of fissile material exposed to neutrons is the prompt emission of high-energy (fast) fission neutrons. One promising mode of operation subjects the object to a beam of medium-energy (epithermal) neutrons, generated by a proton beam impinging on a Li target. The emergence of fast secondary neutrons then clearly indicates the presence of fissile material. Our interrogation system comprises a low-dose 60-keV neutron generator (5 x 10{sup 6}/s), and a 1 m{sup 2} array of scintillators for fast neutron detection. Preliminary experimentalmore » results demonstrate the detectability of small quantities (370 g) of HEU shielded by steel (200 g/cm{sup 2}) or plywood (30 g/cm{sup 2}), with a typical measurement time of 1 min.« less

  17. [Determination of 235U/238U isotope ratios in camphor tree bark samples by MC-ICP-MS after separation of uranium from matrix elements].

    PubMed

    Wang, Xiao-Ping; Zhang, Ji-Long

    2007-07-01

    Twelve camphor (cinnamomum camphora) tree bark samples were collected from Hiroshima and Kyoto, and the matrix element composition and morphology of the outer surface of these camphor tree bark samples were studied by EDXS and SEM respectively. After a dry decomposition, DOWEX 1-X8 anion exchange resin was used to separate uranium from matrix elements in these camphor tree bark samples. Finally, 235U/238 U isotope ratios in purified uranium solutions were determined by MC-ICP-MS. It was demonstrated that the outer surface of these camphor tree bark samples is porous and rough, with Al, Ca, Fe, K, Mg, Si, C, O and S as its matrix element composition. Uranium in these camphor tree bark samples can be efficiently separated and quantitatively recovered from the matrix element composition. Compared with those collected from Kyoto, the camphor tree bark samples collected from Hiroshima have significantly higher uranium contents, which may be due to the increased aerosol mass concentration during the city reconstruction. Moreover, the 235 U/23.U isotope ratios in a few camphor tree bark samples collected from Hiroshima are slightly higher than 0.007 25.

  18. 31 CFR 500.580 - Authorization of U.S. dollar clearing transactions involving North Korea.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... transactions involving North Korea. 500.580 Section 500.580 Money and Finance: Treasury Regulations Relating to... Authorization of U.S. dollar clearing transactions involving North Korea. Banking institutions organized under... North Korea or a national thereof has an interest. Persons subject to U.S. jurisdiction who are...

  19. Uncertainty analysis on reactivity and discharged inventory for a pressurized water reactor fuel assembly due to {sup 235,238}U nuclear data uncertainties

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Da Cruz, D. F.; Rochman, D.; Koning, A. J.

    2012-07-01

    This paper discusses the uncertainty analysis on reactivity and inventory for a typical PWR fuel element as a result of uncertainties in {sup 235,238}U nuclear data. A typical Westinghouse 3-loop fuel assembly fuelled with UO{sub 2} fuel with 4.8% enrichment has been selected. The Total Monte-Carlo method has been applied using the deterministic transport code DRAGON. This code allows the generation of the few-groups nuclear data libraries by directly using data contained in the nuclear data evaluation files. The nuclear data used in this study is from the JEFF3.1 evaluation, and the nuclear data files for {sup 238}U and {supmore » 235}U (randomized for the generation of the various DRAGON libraries) are taken from the nuclear data library TENDL. The total uncertainty (obtained by randomizing all {sup 238}U and {sup 235}U nuclear data in the ENDF files) on the reactor parameters has been split into different components (different nuclear reaction channels). Results show that the TMC method in combination with a deterministic transport code constitutes a powerful tool for performing uncertainty and sensitivity analysis of reactor physics parameters. (authors)« less

  20. Photofission cross-section ratio measurement of 235U/238U using monoenergetic photons in the energy range of 9.0-16.6 MeV

    NASA Astrophysics Data System (ADS)

    Krishichayan; Bhike, Megha; Finch, S. W.; Howell, C. R.; Tonchev, A. P.; Tornow, W.

    2017-05-01

    Photofission cross-section ratios of 235U and 238U have been measured using monoenergetic photon beams at the HIγS facility of TUNL. These measurements have been performed in small energy steps between 9.0 and 16.6 MeV using a dual-fission ionization chamber. Measured cross-section ratios are compared with the previous experimental data as well as with the recent evaluated nuclear data library ENDF.

  1. Pregestational diabetes with extreme insulin resistance: use of U-500 insulin in pregnancy.

    PubMed

    Zuckerwise, Lisa C; Werner, Erika F; Pettker, Christian M; McMahon-Brown, Erin K; Thung, Stephen F; Han, Christina S

    2012-08-01

    Increased insulin requirements in pregnancy can hinder attainment of glycemic control in diabetic patients. U-500 insulin is a concentrated form of regular insulin that can be a valuable tool in the treatment of patients with severe insulin resistance. A 24-year-old woman with pregestational diabetes mellitus experienced increasing insulin requirements during pregnancy, peaking at 650 units daily. The frequent, large-volume injections of standard-concentration insulin were poorly tolerated by the patient and resulted in nonadherence. She subsequently achieved glycemic control on thrice-daily U-500 insulin. Pregnancy exacerbates insulin resistance in diabetic patients, and these patients may require high doses of insulin. U-500 insulin is an effective alternative for patients with severe insulin resistance and should be considered for pregnant women with difficulty achieving glycemic control.

  2. Monsanto Gives Washington U. $23.5 Million.

    ERIC Educational Resources Information Center

    Culliton, Barbara J.

    1982-01-01

    Reviews various provisions of a five-year, $23.5-million research agreement between Washington University and the Monsanto Company. The scientific focus of this venture will be on proteins and peptides which modify cellular behavior. (SK)

  3. 47 CFR 65.500 - Net income.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Net income. 65.500 Section 65.500... OF RETURN PRESCRIPTION PROCEDURES AND METHODOLOGIES Interexchange Carriers § 65.500 Net income. The net income methodology specified in § 65.450 shall be utilized by all interexchange carriers that are...

  4. Regional 500 mb heights and U.S. 1 000-500 mb thickness prior to the radiosonde era

    NASA Astrophysics Data System (ADS)

    Michaels, P. J.; Sappington, D. E.; Stooksbury, D. E.; Hayden, B. P.

    1990-09-01

    We developed a statistical model relating cyclone track eigenvectors over the U.S., southern Canada, and nearby oceans to a record of mean annual 500 mb heights. The length of the cyclone track record allowed us to calculate mean heights back to 1885. Use of mean annual surface pressure data allowed us to estimate the mean 1 000-500 mb thickness, which was related to mean annual temperature. This temperature calculation is unique in that it cannot suffer from urban or site bias. We find a warming of 1.5°C from the late 19th century to 1955, followed by a drop of 0.7° to 1980. By 1987, the calculated temperatures were 0.3° above the mean for 103 years of record. As an example of regional application, we examine results over the southwestern U.S.

  5. Measurement of the normalized U 238 ( n , f ) / U 235 ( n , f ) cross section ratio from threshold to 30 MeV with the NIFFTE fission Time Projection Chamber

    DOE PAGES

    Casperson, R. J.; Asner, D. M.; Baker, J.; ...

    2018-03-23

    We present that the normalized 238U(n,f)/ 235U(n,f) cross section ratio has been measured using the NIFFTE fission Time Projection Chamber (fissionTPC) from the reaction threshold to 30 MeV . The fissionTPC is a two-volume MICROMEGAS time projection chamber that allows for full three-dimensional reconstruction of fission-fragment ionization profiles from neutron-induced fission. The measurement was performed at the Los Alamos Neutron Science Center, where the neutron energy is determined from neutron time of-flight. The 238U(n,f)/ 235U(n,f) ratio reported here is the first cross section measurement made with the fissionTPC, and will provide new experimental data for evaluation of the 238U(n,f) crossmore » section, an important standard used in neutron-flux measurements. Use of a development target in this work prevented the determination of an absolute normalization, to be addressed in future measurements. Instead, the measured cross section ratio has been normalized to ENDF/B-VIII.β5 at 14.5 MeV.« less

  6. Measurement of the normalized 238U(n ,f )/235U(n ,f ) cross section ratio from threshold to 30 MeV with the NIFFTE fission Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Casperson, R. J.; Asner, D. M.; Baker, J.; Baker, R. G.; Barrett, J. S.; Bowden, N. S.; Brune, C.; Bundgaard, J.; Burgett, E.; Cebra, D. A.; Classen, T.; Cunningham, M.; Deaven, J.; Duke, D. L.; Ferguson, I.; Gearhart, J.; Geppert-Kleinrath, V.; Greife, U.; Grimes, S.; Guardincerri, E.; Hager, U.; Hagmann, C.; Heffner, M.; Hensle, D.; Hertel, N.; Higgins, D.; Hill, T.; Isenhower, L. D.; King, J.; Klay, J. L.; Kornilov, N.; Kudo, R.; Laptev, A. B.; Loveland, W.; Lynch, M.; Lynn, W. S.; Magee, J. A.; Manning, B.; Massey, T. N.; McGrath, C.; Meharchand, R.; Mendenhall, M. P.; Montoya, L.; Pickle, N. T.; Qu, H.; Ruz, J.; Sangiorgio, S.; Schmitt, K. T.; Seilhan, B.; Sharma, S.; Snyder, L.; Stave, S.; Tate, A. C.; Tatishvili, G.; Thornton, R. T.; Tovesson, F.; Towell, D. E.; Towell, R. S.; Walsh, N.; Watson, S.; Wendt, B.; Wood, L.; Yao, L.; Younes, W.; Niffte Collaboration

    2018-03-01

    The normalized 238U(n ,f )/235U(n ,f ) cross section ratio has been measured using the NIFFTE fission Time Projection Chamber (fissionTPC) from the reaction threshold to 30 MeV . The fissionTPC is a two-volume MICROMEGAS time projection chamber that allows for full three-dimensional reconstruction of fission-fragment ionization profiles from neutron-induced fission. The measurement was performed at the Los Alamos Neutron Science Center, where the neutron energy is determined from neutron time of-flight. The 238U(n ,f )/235U(n ,f ) ratio reported here is the first cross section measurement made with the fissionTPC, and will provide new experimental data for evaluation of the 238U(n ,f ) cross section, an important standard used in neutron-flux measurements. Use of a development target in this work prevented the determination of an absolute normalization, to be addressed in future measurements. Instead, the measured cross section ratio has been normalized to ENDF/B-VIII.β 5 at 14.5 MeV.

  7. Measurement of the normalized U 238 ( n , f ) / U 235 ( n , f ) cross section ratio from threshold to 30 MeV with the NIFFTE fission Time Projection Chamber

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Casperson, R. J.; Asner, D. M.; Baker, J.

    We present that the normalized 238U(n,f)/ 235U(n,f) cross section ratio has been measured using the NIFFTE fission Time Projection Chamber (fissionTPC) from the reaction threshold to 30 MeV . The fissionTPC is a two-volume MICROMEGAS time projection chamber that allows for full three-dimensional reconstruction of fission-fragment ionization profiles from neutron-induced fission. The measurement was performed at the Los Alamos Neutron Science Center, where the neutron energy is determined from neutron time of-flight. The 238U(n,f)/ 235U(n,f) ratio reported here is the first cross section measurement made with the fissionTPC, and will provide new experimental data for evaluation of the 238U(n,f) crossmore » section, an important standard used in neutron-flux measurements. Use of a development target in this work prevented the determination of an absolute normalization, to be addressed in future measurements. Instead, the measured cross section ratio has been normalized to ENDF/B-VIII.β5 at 14.5 MeV.« less

  8. 31 CFR 500.567 - U.S. assets of certain designated country corporations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false U.S. assets of certain designated country corporations. 500.567 Section 500.567 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FOREIGN ASSETS...

  9. Process for producing enriched uranium having a .sup.235 U content of at least 4 wt. % via combination of a gaseous diffusion process and an atomic vapor laser isotope separation process to eliminate uranium hexafluoride tails storage

    DOEpatents

    Horton, James A.; Hayden, Jr., Howard W.

    1995-01-01

    An uranium enrichment process capable of producing an enriched uranium, having a .sup.235 U content greater than about 4 wt. %, is disclosed which will consume less energy and produce metallic uranium tails having a lower .sup.235 U content than the tails normally produced in a gaseous diffusion separation process and, therefore, eliminate UF.sub.6 tails storage and sharply reduce fluorine use. The uranium enrichment process comprises feeding metallic uranium into an atomic vapor laser isotope separation process to produce an enriched metallic uranium isotopic mixture having a .sup.235 U content of at least about 2 wt. % and a metallic uranium residue containing from about 0.1 wt. % to about 0.2 wt. % .sup.235 U; fluorinating this enriched metallic uranium isotopic mixture to form UF.sub.6 ; processing the resultant isotopic mixture of UF.sub.6 in a gaseous diffusion process to produce a final enriched uranium product having a .sup.235 U content of at least 4 wt. %, and up to 93.5 wt. % or higher, of the total uranium content of the product, and a low .sup.235 U content UF.sub.6 having a .sup.235 U content of about 0.71 wt. % of the total uranium content of the low .sup.235 U content UF.sub.6 ; and converting this low .sup.235 U content UF.sub.6 to metallic uranium for recycle to the atomic vapor laser isotope separation process.

  10. Process for producing enriched uranium having a {sup 235}U content of at least 4 wt. % via combination of a gaseous diffusion process and an atomic vapor laser isotope separation process to eliminate uranium hexafluoride tails storage

    DOEpatents

    Horton, J.A.; Hayden, H.W. Jr.

    1995-05-30

    An uranium enrichment process capable of producing an enriched uranium, having a {sup 235}U content greater than about 4 wt. %, is disclosed which will consume less energy and produce metallic uranium tails having a lower {sup 235}U content than the tails normally produced in a gaseous diffusion separation process and, therefore, eliminate UF{sub 6} tails storage and sharply reduce fluorine use. The uranium enrichment process comprises feeding metallic uranium into an atomic vapor laser isotope separation process to produce an enriched metallic uranium isotopic mixture having a {sup 235} U content of at least about 2 wt. % and a metallic uranium residue containing from about 0.1 wt. % to about 0.2 wt. % {sup 235} U; fluorinating this enriched metallic uranium isotopic mixture to form UF{sub 6}; processing the resultant isotopic mixture of UF{sub 6} in a gaseous diffusion process to produce a final enriched uranium product having a {sup 235}U content of at least 4 wt. %, and up to 93.5 wt. % or higher, of the total uranium content of the product, and a low {sup 235}U content UF{sub 6} having a {sup 235}U content of about 0.71 wt. % of the total uranium content of the low {sup 235}U content UF{sub 6}; and converting this low {sup 235}U content UF{sub 6} to metallic uranium for recycle to the atomic vapor laser isotope separation process. 4 figs.

  11. On similarity of various reactor spectra and 235U prompt fission neutron spectrum.

    PubMed

    Košťál, Michal; Matěj, Zdeněk; Losa, Evžen; Huml, Ondřej; Štefánik, Milan; Cvachovec, František; Schulc, Martin; Jánský, Bohumil; Novák, Evžen; Harutyunyan, Davit; Rypar, Vojtěch

    2018-05-01

    A well-defined neutron spectrum is an essential tool not only for calibration and testing of neutron detectors used in dosimetry and spectroscopy but also for validation and verification of evaluated cross sections. A new evaluation of thermal-neutron induced 235 U PFNS was performed by the International Atomic Energy Agency (IAEA) in the CIELO (Collaborative International Evaluated Library Organisation Project) project; new measurements of Spectral Averaged Cross sections averaged in the evaluated spectrum are to be obtained. In general, a neutron spectrum in the core is not identical to the pure fission one because fission neutrons undergo many scattering reactions, but it can be shown that PFNS and reactor spectra become undistinguishable from a certain energy boundary. This limit is important for experiments, because when the studied reaction threshold is over this limit, the spectral averaged cross sections in PFNS can be derived from the measured reactions in the reactor core. The evaluation of the neutron spectrum measurements in three different thermal-reactor cores shows that this lower limit is around the energy of 5.5 - 6 MeV. Above this energy the reactor spectra becomes identical with the 235 U PFNS. IAEA CIELO PFNS is within 5% of the measured PFNS from 10 to 14 MeV in a LR-0 reactor, while ENDF/B-VII evaluated PFNS underestimated measured neutron spectra. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. On the Relative Signs of "ROT-Effects" in Ternary and Binary Fission of 233U and 235U Nuclei Induced by Polarized Cold Neutrons

    NASA Astrophysics Data System (ADS)

    Danilyan, G. V.

    2018-02-01

    Signs of the ROT-effects in ternary fission of 233U and 235U experimentally defined by PNPI group are the same, whereas in binary fission defined by ITEP group are opposite. This contradiction cannot be explained by the errors in the experiments of both groups, since such instrumental effects would be too large not to be noticed. Therefore, it is necessary to find the answer to this problem in the differences of the ternary and binary fission mechanisms.

  13. Photo-fission Product Yield Measurements at Eγ=13 MeV on 235U, 238U, and 239Pu

    NASA Astrophysics Data System (ADS)

    Tornow, W.; Bhike, M.; Finch, S. W.; Krishichayan, Fnu; Tonchev, A. P.

    2016-09-01

    We have measured Fission Product Yields (FPYs) in photo-fission of 235U, 238U, and 239Pu at TUNL's High-Intensity Gamma-ray Source (HI γS) using mono-energetic photons of Eγ = 13 MeV. Details of the experimental setup and analysis procedures will be discussed. Yields for approximately 20 fission products were determined. They are compared to neutron-induced FPYs of the same actinides at the equivalent excitation energies of the compound nuclear systems. In the future photo-fission data will be taken at Eγ = 8 . 0 and 10.5 MeV to find out whether photo-fission exhibits the same so far unexplained dependence of certain FPYs on the energy of the incident probe, as recently observed in neutron-induced fission, for example, for the important fission product 147Nd. Work supported by the U. S. Dept. of Energy, under Grant No. DE-FG02-97ER41033, and by the NNSA, Stewardship Science Academic Alliances Program, Grant No. DE-NA0001838 and the Lawrence Livermore, National Security, LLC under Contract No. DE-AC52-07NA27344.

  14. Radial dependence of lineal energy distribution of 290-MeV/u carbon and 500-MeV/u iron ion beams using a wall-less tissue-equivalent proportional counter.

    PubMed

    Tsuda, Shuichi; Sato, Tatsuhiko; Watanabe, Ritsuko; Takada, Masashi

    2015-01-01

    Using a wall-less tissue-equivalent proportional counter for a 0.72-μm site in tissue, we measured the radial dependence of the lineal energy distribution, yf(y), of 290-MeV/u carbon ions and 500-MeV/u iron ion beams. The measured yf(y) distributions and the dose-mean of y, [Formula: see text], were compared with calculations performed with the track structure simulation code TRACION and the microdosimetric function of the Particle and Heavy Ion Transport code System (PHITS). The values of the measured [Formula: see text] were consistent with calculated results within an error of 2%, but differences in the shape of yf(y) were observed for iron ion irradiation. This result indicates that further improvement of the calculation model for yf(y) distribution in PHITS is needed for the analytical function that describes energy deposition by delta rays, particularly for primary ions having linear energy transfer in excess of a few hundred keV μm(-1). © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  15. Photofission cross-section ratio measurement of 235 U/ 238 U using monoenergetic photons in the energy range of 9.0–16.6 MeV

    DOE PAGES

    Krishichayan,; Bhike, Megha; Finch, S. W.; ...

    2017-05-01

    Photofission cross-section ratios of 235U and 238U have been measured using monoenergetic photon beams from the High Intensity Gamma-ray Source facility at the Triangle Universities Nuclear Laboratory. These measurements have been performed in small energy steps between 9.0 and 16.6 MeV using a dual-fission ionization chamber. The measured cross-section ratios are compared with the previous experimental data as well as with the recent evaluated nuclear data library ENDF.

  16. 31 CFR 500.602 - Reporting of claims of U.S. nationals against North Korea.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... against North Korea. 500.602 Section 500.602 Money and Finance: Treasury Regulations Relating to Money and... REGULATIONS Reports § 500.602 Reporting of claims of U.S. nationals against North Korea. (a) Requirement for... North Korea or any North Korean government entity. (b) Who must report. A report must be submitted by...

  17. Measurement of high-energy prompt gamma-rays from neutron induced fission of U-235

    NASA Astrophysics Data System (ADS)

    Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, Riccardo; Léguillon, Romain; Ogawa, Tatsuhiko; Soldner, Torsten; Hambsch, Franz-Josef; Astier, Alain; Pollitt, Andrew; Petrache, Costel; Tsekhanovich, Igor; Mathieu, Ludovic; Aïche, Mourad; Frost, Robert; Czajkowski, Serge; Guo, Song; Köster, Ulli

    2017-09-01

    We have developed a new setup to measure prompt γ-rays from the 235U(nth,f) reaction. The setup consists of two multi-wire proportional counters (MWPCs) to detect the fission fragments, two LaBr3(Ce) scintillators to measure the γ-rays. The highly efficient setup was installed at the PF1B beam line of the Institut Laue Langevin (ILL). We have successfully measured the γ-ray spectrum up to about 20 MeV for the fist time in neutron-induced fission.

  18. Short Lived Fission Product Yield Measurements in 235U, 238U and 239Pu

    NASA Astrophysics Data System (ADS)

    Silano, Jack; Tonchev, Anton; Tornow, Werner; Krishichayan, Fnu; Finch, Sean; Gooden, Matthew; Wilhelmy, Jerry

    2017-09-01

    Yields of short lived fission products (FPYs) with half lives of a few minutes to an hour contain a wealth of information about the fission process. Knowledge of short lived FPYs would contribute to existing data on longer lived FPY mass and charge distributions. Of particular interest are the relative yields between the ground states and isomeric states of FPYs since these isomeric ratios can be used to determine the angular momentum of the fragments. Over the past five years, a LLNL-TUNL-LANL collaboration has made precision measurements of FPYs from quasi-monoenergetic neutron induced fission of 235U, 238U and 239Pu. These efforts focused on longer lived FPYs, using a well characterized dual fission chamber and several days of neutron beam exposure. For the first time, this established technique will be applied to measuring short lived FPYs, with half lives of minutes to less than an hour. A feasibility study will be performed using irradiation times of < 1 hour, improving the sensitivity to short lived FPYs by limiting the buildup of long lived isotopes. Results from this exploratory study will be presented, and the implications for isomeric ratio measurements will be discussed. This work was performed under the auspices of US DOE by LLNL under Contract DE-AC52-07NA27344.

  19. The Prompt Fission Neutron Spectrum of 235U for Einc 0.7-5.0 MeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gomez, Jaime A.; Devlin, Matthew James; Haight, Robert Cameron

    2017-03-23

    The Chi-Nu experiment aims to accurately measure the prompt fission neutron spectrum (PFNS) for the major actinides. At the Los Alamos Neutron Science Center (LANSCE), fission can be induced using the white neutron source. Using a two arm time of flight (T.O.F) technique; Chi-Nu presents a preliminary result of the low energy component of the 235U PFNS measured using an array of 22-Lithium glass scintillators.

  20. Translating U-500R Randomized Clinical Trial Evidence to the Practice Setting: A Diabetes Educator/Expert Prescriber Team Approach.

    PubMed

    Bergen, Paula M; Kruger, Davida F; Taylor, April D; Eid, Wael E; Bhan, Arti; Jackson, Jeffrey A

    2017-06-01

    Purpose The purpose of this article is to provide recommendations to the diabetes educator/expert prescriber team for the use of human regular U-500 insulin (U-500R) in patients with severely insulin-resistant type 2 diabetes, including its initiation and titration, by utilizing dosing charts and teaching materials translated from a recent U-500R clinical trial. Conclusions Clinically relevant recommendations and teaching materials for the optimal use and management of U-500R in clinical practice are provided based on the efficacy and safety results of and lessons learned from the U-500R clinical trial by Hood et al, current standards of practice, and the authors' clinical expertise. This trial was the first robustly powered, randomized, titration-to-target trial to compare twice-daily and three-times-daily U-500R dosing regimens. Modifications were made to the initiation and titration dosing algorithms used in this trial to simplify dosing strategies for the clinical setting and align with current glycemic targets recommended by the American Diabetes Association. Leveraging the expertise, resources, and patient interactions of the diabetes educator who can provide diabetes self-management education and support in collaboration with the multidisciplinary diabetes team is strongly recommended to ensure patients treated with U-500R receive the timely and comprehensive care required to safely and effectively use this highly concentrated insulin.

  1. Translating U-500R Randomized Clinical Trial Evidence to the Practice Setting: A Diabetes Educator/Expert Prescriber Team Approach

    PubMed Central

    Bergen, Paula M.; Kruger, Davida F.; Taylor, April D.; Eid, Wael E.; Bhan, Arti; Jackson, Jeffrey A.

    2017-01-01

    Purpose The purpose of this article is to provide recommendations to the diabetes educator/expert prescriber team for the use of human regular U-500 insulin (U-500R) in patients with severely insulin-resistant type 2 diabetes, including its initiation and titration, by utilizing dosing charts and teaching materials translated from a recent U-500R clinical trial. Conclusions Clinically relevant recommendations and teaching materials for the optimal use and management of U-500R in clinical practice are provided based on the efficacy and safety results of and lessons learned from the U-500R clinical trial by Hood et al, current standards of practice, and the authors’ clinical expertise. This trial was the first robustly powered, randomized, titration-to-target trial to compare twice-daily and three-times-daily U-500R dosing regimens. Modifications were made to the initiation and titration dosing algorithms used in this trial to simplify dosing strategies for the clinical setting and align with current glycemic targets recommended by the American Diabetes Association. Leveraging the expertise, resources, and patient interactions of the diabetes educator who can provide diabetes self-management education and support in collaboration with the multidisciplinary diabetes team is strongly recommended to ensure patients treated with U-500R receive the timely and comprehensive care required to safely and effectively use this highly concentrated insulin. PMID:28427304

  2. Prompt fission neutron emission in the reaction 235U(n,f)

    NASA Astrophysics Data System (ADS)

    Göök, Alf; Hambsch, Franz-Josef; Oberstedt, Stephan

    2018-03-01

    Experimental activities at JRC-Geel on prompt fission neutron (PFN) emission in response to OECD/NEA nuclear data requests are presented in this contribution. Specifically, on-going investigations of PFN emission from the reaction 235U(n,f) in the region of the resolved resonances, taking place at the GELINA facility, are presented. The focus of this contribution lies on studies of PFN correlations with fission fragment properties. The experiment employs a scintillation detector array for neutron detection, while fission fragment properties are determined via the double kinetic energy technique using a position sensitive twin ionization chamber. This setup allows us to study several correlations between properties of neutron and fission fragments simultaneously. Results on PFN correlations with fission fragment properties from the present study differ significantly from earlier studies on this reaction, induced by thermal neutrons.

  3. A new experimental proposal for {sup 235}U PFNS to answer a fifty years old question

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kornilov, N.; Massey, T.; Grimes, S.

    2011-07-01

    The Prompt Fission Neutron Spectrum (PFNS) from {sup 235}U(n,f) is very important for various nuclear applications. It has been investigated in different experiments. In spite of {approx}50 years of experimental efforts, a continuing conflict exists at thermal neutron energy. Microscopic experimental PFNS cannot describe macroscopic data. In this report we discuss the current status of this problem and suggest a new experiment, which could possibly resolve this problem. (authors)

  4. Feasibility study of 235U and 239Pu characterization in radioactive waste drums using neutron-induced fission delayed gamma rays

    NASA Astrophysics Data System (ADS)

    Nicol, T.; Pérot, B.; Carasco, C.; Brackx, E.; Mariani, A.; Passard, C.; Mauerhofer, E.; Collot, J.

    2016-10-01

    This paper reports a feasibility study of 235U and 239Pu characterization in 225 L bituminized waste drums or 200 L concrete waste drums, by detecting delayed fission gamma rays between the pulses of a deuterium-tritium neutron generator. The delayed gamma yields were first measured with bare samples of 235U and 239Pu in REGAIN, a facility dedicated to the assay of 118 L waste drums by Prompt Gamma Neutron Activation Analysis (PGNAA) at CEA Cadarache, France. Detectability in the waste drums is then assessed using the MCNPX model of MEDINA (Multi Element Detection based on Instrumental Neutron Activation), another PGNAA cell dedicated to 200 L drums at FZJ, Germany. For the bituminized waste drum, performances are severely hampered by the high gamma background due to 137Cs, which requires the use of collimator and shield to avoid electronics saturation, these elements being very penalizing for the detection of the weak delayed gamma signal. However, for lower activity concrete drums, detection limits range from 10 to 290 g of 235U or 239Pu, depending on the delayed gamma rays of interest. These detection limits have been determined by using MCNPX to calculate the delayed gamma useful signal, and by measuring the experimental gamma background in MEDINA with a 200 L concrete drum mock-up. The performances could be significantly improved by using a higher interrogating neutron emission and an optimized experimental setup, which would allow characterizing nuclear materials in a wide range of low and medium activity waste packages.

  5. Measurement of U-235 Fission Neutron Spectra Using a Multiple Gamma Coincidence Technique

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ji Chuncheng; Kegel, G.H.R.; Egan, J.J.

    2005-05-24

    The Los Alamos Model of Madland and Nix predicts the shape of the fission neutron energy spectrum for incident primary neutrons of different energies. Verifications of the model normally are limited to measurements of the fission neutron spectra for energies higher than that of the primary neutrons because the low-energy spectrum is distorted by the admixture of elastically and inelastically scattered neutrons. This situation can be remedied by using a measuring technique that separates fission from scattering events. One solution consists of using a fissile sample so thin that fission fragments can be observed indicating the occurrence of a fissionmore » event. A different approach is considered in this paper. It has been established that a fission event is accompanied by the emission of between seven and eight gamma rays, while in a scattering interaction, between zero and two gammas are emitted, so that a gamma multiplicity detector should supply a datum to distinguish a fission event from a scattering event. We proceed as follows: A subnanosecond pulsed and bunched proton beam from the UML Van de Graaff generates nearly mono-energetic neutrons by irradiating a thin metallic lithium target. The neutrons irradiate a 235U sample. Emerging neutron energies are measured with a time-of-flight spectrometer. A set of four BaF2 detectors is located close to the 235U sample. These detectors together with their electronic components identify five different events for each neutron detected, i.e., whether four, three, two, one, or none of the BaF2 detectors received one (or more) gamma rays. We present work, preliminary to the final measurements, involving feasibility considerations based on gamma-ray coincidence measurements with four BaF2 detectors, and the design of a Fission-Scattering Discriminator under construction.« less

  6. Accurate measurement of the first excited nuclear state in 235U

    NASA Astrophysics Data System (ADS)

    Ponce, F.; Swanberg, E.; Burke, J.; Henderson, R.; Friedrich, S.

    2018-05-01

    We have used superconducting high-resolution radiation detectors to measure the energy level of metastable Um235 as 76.737 ± 0.018 eV. The Um235 isomer is created from the α decay of 239Pu and embedded directly into the detector. When the Um235 subsequently decays, the energy is fully contained within the detector and is independent of the decay mode or the chemical state of the uranium. The detector is calibrated using an energy comb from a pulsed UV laser. A comparable measurement of the metastable Thm229 nucleus would enable a laser search for the exact transition energy in 229Th-Thm229 as a step towards developing the first ever nuclear (baryonic) clock.

  7. Neutron-induced fission cross-section measurement of 234U with quasi-monoenergetic beams in the keV and MeV range using micromegas detectors

    NASA Astrophysics Data System (ADS)

    Tsinganis, A.; Kokkoris, M.; Vlastou, R.; Kalamara, A.; Stamatopoulos, A.; Kanellakopoulos, A.; Lagoyannis, A.; Axiotis, M.

    2017-09-01

    Accurate data on neutron-induced fission cross-sections of actinides are essential for the design of advanced nuclear reactors based either on fast neutron spectra or alternative fuel cycles, as well as for the reduction of safety margins of existing and future conventional facilities. The fission cross-section of 234U was measured at incident neutron energies of 560 and 660 keV and 7.5 MeV with a setup based on `microbulk' Micromegas detectors and the same samples previously used for the measurement performed at the CERN n_TOF facility (Karadimos et al., 2014). The 235U fission cross-section was used as reference. The (quasi-)monoenergetic neutron beams were produced via the 7Li(p,n) and the 2H(d,n) reactions at the neutron beam facility of the Institute of Nuclear and Particle Physics at the `Demokritos' National Centre for Scientific Research. A detailed study of the neutron spectra produced in the targets and intercepted by the samples was performed coupling the NeuSDesc and MCNPX codes, taking into account the energy spread, energy loss and angular straggling of the beam ions in the target assemblies, as well as contributions from competing reactions and neutron scattering in the experimental setup. Auxiliary Monte-Carlo simulations were performed with the FLUKA code to study the behaviour of the detectors, focusing particularly on the reproduction of the pulse height spectra of α-particles and fission fragments (using distributions produced with the GEF code) for the evaluation of the detector efficiency. An overview of the developed methodology and preliminary results are presented.

  8. Charge dynamics of MgO single crystals subjected to KeV electron irradiation

    NASA Astrophysics Data System (ADS)

    Boughariou, A.; Blaise, G.; Braga, D.; Kallel, A.

    2004-04-01

    A scanning electron microscope has been equipped to study the fundamental aspects of charge trapping in insulating materials, by measuring the secondary electron emission (SEE) yield σ with a high precision (a few percent), as a function of energy, electron current density, and dose. The intrinsic secondary electron emission yield σ0 of uncharged MgO single crystals annealed at 1000 °C, 2 h, has been studied at four energies 1.1, 5, 15, and 30 keV on three different crystal orientations (100), (110), and (111). At low energies (1.1 and 5 keV) σ0 depends on the crystalline orientation wheras at high energies (30 keV) no differentiation occurs. It is shown that the value of the second crossover energy E2, for which the intrinsic SEE yield σ0=1, is extremely delicate to measure with precision. It is about 15 keV±500 eV for the (100) orientation, 13.5 keV±500 eV for the (110), and 18.5 keV±500 eV for the (111) one. At low current density J⩽105 pA/cm2, the variation of σ with the injected dose makes possible the observation of a self-regulated regime characterized by a steady value of the SEE yield σst=1. At low energies 1.1 and 5 keV, there is no current density effects in MgO, but at high energies ≈30 keV, apparent current density effects come from a bad collect of secondary electrons, due to very high negative surface potential. At 30 keV energy, an intense erratic electron exoemission was observed on the MgO (110) orientation annealed at 1500 °C. This phenomenon is the result of a disruptive process similar to flashover, which takes place at the surface of the material.

  9. Neutron Fission of 235,237,239U and 241,243Pu: Cross Sections, Integral Cross Sections and Cross Sections on Excited States

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Younes, W; Britt, H C

    In a recent paper submitted to Phys. Rev. C they have presented estimates for (n,f) cross sections on a series of Thorium, Uranium and Plutonium isotopes over the range E{sub n} = 0.1-2.5 MeV. The (n,f) cross sections for many of these isotopes are difficult or impossible to measure in the laboratory. The cross sections were obtained from previous (t,pf) reaction data invoking a model which takes into account the differences between (t,pf) and (n,f) reaction processes, and which includes improved estimates for the neutron compound formation process. The purpose of this note is: (1) to compare the estimated crossmore » sections to current data files in both ENDF and ENDL databases; (2) to estimate ratios of cross sections relatively to {sup 235}U integrated over the ''tamped flattop'' critical assembly spectrum that was used in the earlier {sup 237}U report; and (3) to show the effect on the integral cross sections when the neutron capturing state is an excited rotational state or an isomer. The isomer and excited state results are shown for {sup 235}U and {sup 237}U.« less

  10. Fission fragment yields and total kinetic energy release in neutron-induced fission of235,238U,and239Pu

    NASA Astrophysics Data System (ADS)

    Tovesson, F.; Duke, D.; Geppert-Kleinrath, V.; Manning, B.; Mayorov, D.; Mosby, S.; Schmitt, K.

    2018-03-01

    Different aspects of the nuclear fission process have been studied at Los Alamos Neutron Science Center (LANSCE) using various instruments and experimental techniques. Properties of the fragments emitted in fission have been investigated using Frisch-grid ionization chambers, a Time Projection Chamber (TPC), and the SPIDER instrument which employs the 2v-2E method. These instruments and experimental techniques have been used to determine fission product mass yields, the energy dependent total kinetic energy (TKE) release, and anisotropy in neutron-induced fission of U-235, U-238 and Pu-239.

  11. Using the Time-Correlated Induced Fission Method to Simultaneously Measure the 235U Content and the Burnable Poison Content in LWR Fuel Assemblies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Root, M. A.; Menlove, H. O.; Lanza, R. C.

    The uranium neutron coincidence collar uses thermal neutron interrogation to verify the 235U mass in low-enriched uranium (LEU) fuel assemblies in fuel fabrication facilities. Burnable poisons are commonly added to nuclear fuel to increase the lifetime of the fuel. The high thermal neutron absorption by these poisons reduces the active neutron signal produced by the fuel. Burnable poison correction factors or fast-mode runs with Cd liners can help compensate for this effect, but the correction factors rely on operator declarations of burnable poison content, and fast-mode runs are time-consuming. Finally, this paper describes a new analysis method to measure themore » 235U mass and burnable poison content in LEU nuclear fuel simultaneously in a timely manner, without requiring additional hardware.« less

  12. Using the Time-Correlated Induced Fission Method to Simultaneously Measure the 235U Content and the Burnable Poison Content in LWR Fuel Assemblies

    DOE PAGES

    Root, M. A.; Menlove, H. O.; Lanza, R. C.; ...

    2018-03-21

    The uranium neutron coincidence collar uses thermal neutron interrogation to verify the 235U mass in low-enriched uranium (LEU) fuel assemblies in fuel fabrication facilities. Burnable poisons are commonly added to nuclear fuel to increase the lifetime of the fuel. The high thermal neutron absorption by these poisons reduces the active neutron signal produced by the fuel. Burnable poison correction factors or fast-mode runs with Cd liners can help compensate for this effect, but the correction factors rely on operator declarations of burnable poison content, and fast-mode runs are time-consuming. Finally, this paper describes a new analysis method to measure themore » 235U mass and burnable poison content in LEU nuclear fuel simultaneously in a timely manner, without requiring additional hardware.« less

  13. The 235U prompt fission neutron spectrum measured by the Chi-Nu project at LANSCE

    DOE PAGES

    Gomez, J. A.; Devlin, M.; Haight, R. C.; ...

    2017-09-13

    The Chi-Nu experiment aims to accurately measure the prompt fission neutron spectrum for the major actinides. At the Los Alamos Neutron Science Center (LANSCE), fission can be induced with neutrons ranging from 0.7 MeV and above. Using a two arm time-of-flight (TOF) technique, the fission neutrons are measured in one of two arrays: a 22- 6Li glass array for lower energies, or a 54-liquid scintillator array for outgoing energies of 0.5 MeV and greater. Presented here are the collaboration's preliminary efforts at measuring the 235U PFNS.

  14. The 235U prompt fission neutron spectrum measured by the Chi-Nu project at LANSCE

    NASA Astrophysics Data System (ADS)

    Gomez, J. A.; Devlin, M.; Haight, R. C.; O'Donnell, J. M.; Lee, H. Y.; Mosby, S. M.; Taddeucci, T. N.; Kelly, K. J.; Fotiades, N.; Neudecker, D.; White, M. C.; Talou, P.; Rising, M. E.; Solomon, C. J.; Wu, C. Y.; Bucher, B.; Buckner, M. Q.; Henderson, R. A.

    2017-09-01

    The Chi-Nu experiment aims to accurately measure the prompt fission neutron spectrum for the major actinides. At the Los Alamos Neutron Science Center (LANSCE), fission can be induced with neutrons ranging from 0.7 MeV and above. Using a two arm time-of-flight (TOF) technique, the fission neutrons are measured in one of two arrays: a 22-6Li glass array for lower energies, or a 54-liquid scintillator array for outgoing energies of 0.5 MeV and greater. Presented here are the collaboration's preliminary efforts at measuring the 235U PFNS.

  15. Measurement of the 238U(n ,γ ) cross section up to 80 keV with the Total Absorption Calorimeter at the CERN n_TOF facility

    NASA Astrophysics Data System (ADS)

    Wright, T.; Guerrero, C.; Billowes, J.; Cano-Ott, D.; Mendoza, E.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Barbagallo, M.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Bosnar, D.; Brugger, M.; Calviño, F.; Calviani, M.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Dietz, M.; Domingo-Pardo, C.; Durán, I.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Furman, V.; Gómez-Hornillos, M. B.; Ganesan, S.; García, A. R.; Giubrone, G.; Gonçalves, I. F.; González-Romero, E.; Goverdovski, A.; Griesmayer, E.; Gunsing, F.; Gurusamy, P.; Heftrich, T.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Käppeler, F.; Kadi, Y.; Karadimos, D.; Katabuchi, T.; Ketlerov, V.; Khryachkov, V.; Koehler, P.; Kokkoris, M.; Kroll, J.; Krtička, M.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Leong, L. S.; Lerendegui-Marco, J.; Losito, R.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Paradela, C.; Pavlik, A.; Perkowski, J.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego-Perez, A.; Robles, M.; Roman, F.; Rubbia, C.; Ryan, J. A.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Sedyshev, P.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vermeulen, M. J.; Versaci, R.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiss, C.; Žugec, P.; n TOF Collaboration

    2017-12-01

    The radiative capture cross section of a highly pure (99.999%), 6.125(2) grams and 9.56(5)×10-4 atoms/barn areal density 238U sample has been measured with the Total Absorption Calorimeter (TAC) in the 185 m flight path at the CERN neutron time-of-flight facility n_TOF. This measurement is in response to the NEA High Priority Request list, which demands an accuracy in this cross section of less than 3% below 25 keV. These data have undergone careful background subtraction, with special care being given to the background originating from neutrons scattered by the 238U sample. Pileup and dead-time effects have been corrected for. The measured cross section covers an energy range between 0.2 eV and 80 keV, with an accuracy that varies with neutron energy, being better than 4% below 25 keV and reaching at most 6% at higher energies.

  16. Plant uptake of 238U, 235U, 232Th, 226Ra, 210Pb and 40K from a coal ash and slag disposal site and control soil under field conditions: A preliminary study.

    PubMed

    Skoko, Božena; Marović, Gordana; Babić, Dinko; Šoštarić, Marko; Jukić, Mirela

    2017-06-01

    The aim of this study was to investigate the uptake of 238 U, 235 U, 232 Th, 226 Ra, 210 Pb and 40 K by plants that grow on a coal ash and slag disposal site known for its higher content of naturally occurring radionuclides. Plant species that were sampled are common for the Mediterranean flora and can be divided as follows: grasses & herbs, shrubs and trees. To compare the activity concentrations and the resultant concentration ratios of the disposal site with those in natural conditions, we used control data specific for the research area, obtained for plants growing on untreated natural soil. Radionuclide activity concentrations were determined by high resolution gamma-ray spectrometry. Media parameters (pH, electrical conductivity and organic matter content) were also analysed. We confirmed significantly higher activity concentrations of 238 U, 235 U, 226 Ra and 210 Pb in ash and slag compared to control soil. However, a significant increase in the radionuclide activity concentration in the disposal site's vegetation was observed only for 226 Ra. On the contrary, a significantly smaller activity concentration of 40 K in ash and slag had no impact on its activity concentration in plant samples. The calculated plant uptake of 238 U, 235 U, 226 Ra and 210 Pb is significantly smaller in comparison with the uptake at the control site, while it is vice versa for 40 K. No significant difference was observed between the disposal site and the control site's plant uptake of 232 Th. These results can be the foundation for further radioecological assessment of this disposal site but also, globally, they can contribute to a better understanding of nature and long-term management of such disposal sites. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 8 CFR 235.10 - U.S. Citizen Identification Card.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Section 235.10 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS INSPECTION... demands an opportunity to see and rebut the adverse evidence. Any rebuttal, explanation, or evidence... whom it was issued admits in a statement signed before an immigration officer that he or she is an...

  18. 14 CFR 1212.500 - Exemptions under 5 U.S.C. 552a (j) and (k).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Exemptions under 5 U.S.C. 552a (j) and (k). 1212.500 Section 1212.500 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PRIVACY.... 552a (j) and (k). (a) These provisions authorize the Administrator of NASA to exempt certain NASA...

  19. 14 CFR 1212.500 - Exemptions under 5 U.S.C. 552a (j) and (k).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Exemptions under 5 U.S.C. 552a (j) and (k). 1212.500 Section 1212.500 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PRIVACY.... 552a (j) and (k). (a) These provisions authorize the Administrator of NASA to exempt certain NASA...

  20. 14 CFR 1212.500 - Exemptions under 5 U.S.C. 552a (j) and (k).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Exemptions under 5 U.S.C. 552a (j) and (k). 1212.500 Section 1212.500 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PRIVACY.... 552a (j) and (k). (a) These provisions authorize the Administrator of NASA to exempt certain NASA...

  1. 14 CFR 1212.500 - Exemptions under 5 U.S.C. 552a (j) and (k).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Exemptions under 5 U.S.C. 552a (j) and (k). 1212.500 Section 1212.500 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PRIVACY.... 552a (j) and (k). (a) These provisions authorize the Administrator of NASA to exempt certain NASA...

  2. Measurement of the energy and multiplicity distributions of neutrons from the photofission of U 235

    DOE PAGES

    Clarke, S. D.; Wieger, B. M.; Enqvist, A.; ...

    2017-06-20

    For the first time, the complete neutron multiplicity distribution has been measured in this study from the photofission of 235U induced by high-energy spallation γ rays arriving ahead of the neutron beam at the Los Alamos Neutron Science Center. The resulting average neutron multiplicity 3.80 ± 0.08 (stat.) neutrons per photofission is in general agreement with previous measurements. In addition, unique measurements of the prompt fission energy spectrum of the neutrons from photofission and the angular correlation of two-neutron energies emitted in photofission also were made. Finally, the results are compared to calculations with the complete event fission model FREYA.

  3. Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN - n_TOF

    NASA Astrophysics Data System (ADS)

    Diakaki, M.; Audouin, L.; Berthoumieux, E.; Calviani, M.; Colonna, N.; Dupont, E.; Duran, I.; Gunsing, F.; Leal-Cidoncha, E.; Le Naour, C.; Leong, L. S.; Mastromarco, M.; Paradela, C.; Tarrio, D.; Tassan-Got, L.; Aerts, G.; Altstadt, S.; Alvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Badurek, G.; Barbagallo, M.; Baumann, P.; Becares, V.; Becvar, F.; Belloni, F.; Berthier, B.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calvino, F.; Cano-Ott, D.; Capote, R.; Carrapiço, C.; Cennini, P.; Cerutti, F.; Chiaveri, E.; Chin, M.; Cortes, G.; Cortes-Giraldo, M. A.; Cosentino, L.; Couture, A.; Cox, J.; David, S.; Dillmann, I.; Domingo-Pardo, C.; Dressler, R.; Dridi, W.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Finocchiaro, P.; Fraval, K.; Fujii, K.; Furman, W.; Ganesan, S.; Garcia, A. R.; Giubrone, G.; Gomez-Hornillos, M. B.; Goncalves, I. F.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gurusamy, P.; Haight, R.; Heil, M.; Heinitz, S.; Igashira, M.; Isaev, S.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Kaeppeler, F.; Karadimos, D.; Karamanis, D.; Kerveno, M.; Ketlerov, V.; Kivel, N.; Kokkoris, M.; Konovalov, V.; Krticka, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Lederer, C.; Leeb, H.; Lo Meo, S.; Losito, R.; Lozano, M.; Manousos, A.; Marganiec, J.; Martinez, T.; Marrone, S.; Massimi, C.; Mastinu, P.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondelaers, W.; Moreau, C.; Mosconi, M.; Musumarra, A.; O'Brien, S.; Pancin, J.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perkowski, J.; Perrot, L.; Pigni, M. T.; Plag, R.; Plompen, A.; Plukis, L.; Poch, A.; Pretel, C.; Praena, J.; Quesada, J.; Rauscher, T.; Reifarth, R.; Riego, A.; Roman, F.; Rudolf, G.; Rubbia, C.; Rullhusen, P.; Salgado, J.; Santos, C.; Sarchiapone, L.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Stephan, C.; Tagliente, G.; Tain, J. L.; Tavora, L.; Terlizzi, R.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Villamarin, D.; Vincente, M. C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Wallner, A.; Walter, S.; Ware, T.; Weigand, M.; Weiß, C.; Wiesher, M.; Wisshak, K.; Wright, T.; Zugec, P.

    2016-03-01

    The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN - n_TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards.

  4. Determination of 20Ne(p ,γ )21Na cross sections from Ep=500 -2000 keV

    NASA Astrophysics Data System (ADS)

    Lyons, S.; Görres, J.; deBoer, R. J.; Stech, E.; Chen, Y.; Gilardy, G.; Liu, Q.; Long, A. M.; Moran, M.; Robertson, D.; Seymour, C.; Vande Kolk, B.; Wiescher, M.; Best, A.

    2018-06-01

    Background: The reaction 20Ne(p ,γ )21Na influences the nucleosynthesis of Ne, Na, and Mg isotopes while contributing to hydrogen burning in several stellar sites, such as red giants, asymptotic giant branch (AGB) stars, massive stars, and oxygen-neon (ONe) novae. In the relevant temperature range for these environments (T = 0.05-0.5 GK), the main contributions to this reaction rate are from the direct capture process as well as the high-energy tail of a subthreshold resonance in the ground-state transition at Ex = 2425 keV in the 21Na compound nucleus. Purpose: The previous measurement of this reaction reports cross sections with large uncertainties for the ground-state transition. At higher energies, where the subthreshold resonance makes a smaller contribution to the total cross section, only upper limits are provided. This work aims to reduce the uncertainty in the cross section where direct capture dominates, as well as provide cross-section data in previously unmeasured regions. Method: The 20Ne(p ,γ )21Na reaction was measured over a wide proton energy range (Ep = 0.5-2.0 MeV) at θlab = 90∘. Transitions to the ground state and to the 332 and 2425 keV excited states were observed. The primary transitions to these three bound states were utilized in an R -matrix analysis to determine the contributions of the direct capture and the subthreshold resonance to the total cross section. Results: The cross sections of the present measurements have been found to be in good agreement with the previous data at low energy. Significantly improved cross-section measurements have been obtained over the Ep = 1300-1900 keV region. The narrow resonance at Ec.m. = 1113 keV (Ex = 3544.3 keV) has also been remeasured and its strength has been found to be in good agreement with previous measurements. Conclusions: An extrapolation of the S factor of 20Ne(p ,γ )21Na has been made to low energies using the R -matrix fit. The reaction rate from the subthreshold resonance was

  5. Validation of the fission yield and decay data libraries with the 10 s-delayed 235 U fission γ-ray energy spectrum

    NASA Astrophysics Data System (ADS)

    Mendoza, E.; Álvarez-Velarde, F.; Bécares, V.; Cano-Ott, D.; González-Romero, E.; Martínez, T.; Villamarín, D.

    2017-10-01

    We have measured with a LaCl3 detector the γ-ray spectrum emitted by a 235 U enriched UO2 fuel rod 10 s after being irradiated with thermal neutrons. The experimental results are compared with simulations performed with the fission product yield and radioactive decay data libraries present in the most recent releases of ENDF/B, JEFF and JENDL.

  6. 14 CFR § 1212.500 - Exemptions under 5 U.S.C. 552a (j) and (k).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Exemptions under 5 U.S.C. 552a (j) and (k). § 1212.500 Section § 1212.500 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION....C. 552a (j) and (k). (a) These provisions authorize the Administrator of NASA to exempt certain NASA...

  7. Nuclear Data Sheets for A = 235

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Browne, E.; Tuli, J.K.

    Spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented here for all nuclei with mass number A=235. The highlight of this evaluation consists of the precise and comprehensive Coulomb excitation study (2012Wa35) on {sup 235}U, which in addition to the 7/2[743] ground state rotational band, extended the 1/2[631], 5/2[622], 5/2[752], and 3/2[631] rotational bands up to Jπ=53/2+, 49/2+, 441/2−, and 43/2+, respectively. This evaluation presents a study (2010Hu02) of the {sup 237}Np({sup 116}Sn, {sup 118}Snγ) reaction where the ground state rotational band 5/2[642] was observed up to Jπ=(53/2+). It is worth for historical knowledge tomore » mention the report on the “Discovery of isotopes of the transuranium elements with 93≤Z≤98” (2013Fr02), where the information for elements Np, Pu, and Am with mass number A=235 is given. {sup 235}Cf has not been observed. The alpha hindrance factors (HF) presented in this evaluation were calculated using values of the radius parameter (r{sub 0}) interpolated from those for even–even adjacent nuclei given by 1998Ak04.« less

  8. Calculated criticality for sup 235 U/graphite systems using the VIM Monte Carlo code

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Collins, P.J.; Grasseschi, G.L.; Olsen, D.N.

    1992-01-01

    Calculations for highly enriched uranium and graphite systems gained renewed interest recently for the new production modular high-temperature gas-cooled reactor (MHTGR). Experiments to validate the physics calculations for these systems are being prepared for the Transient Reactor Test Facility (TREAT) reactor at Argonne National Laboratory (ANL-West) and in the Compact Nuclear Power Source facility at Los Alamos National Laboratory. The continuous-energy Monte Carlo code VIM, or equivalently the MCNP code, can utilize fully detailed models of the MHTGR and serve as benchmarks for the approximate multigroup methods necessary in full reactor calculations. Validation of these codes and their associated nuclearmore » data did not exist for highly enriched {sup 235}U/graphite systems. Experimental data, used in development of more approximate methods, dates back to the 1960s. The authors have selected two independent sets of experiments for calculation with the VIM code. The carbon-to-uranium (C/U) ratios encompass the range of 2,000, representative of the new production MHTGR, to the ratio of 10,000 in the fuel of TREAT. Calculations used the ENDF/B-V data.« less

  9. Evaluation of Total Daily Dose and Glycemic Control for Patients on U-500 Insulin Admitted to the Hospital

    DTIC Science & Technology

    2016-05-20

    regular insulin has significantly increased in recent years. These patients are severely insulin resistant requiring high doses of insulin to achieve...on U-500 Insulin Admitted to the Hospital presented at SURF Conference, San Antonio, TX 20 May 201 6 with MDWI 41-108, and has been assigned local...59th CSPG/SGVU) C.201 4 . I 52d PROTOCOL TITLE Evaluation of Total Dai ly Dose and Glycemic Control for Patients on U-500 Insulin Admitted to the

  10. Fuel cycle cost, reactor physics and fuel manufacturing considerations for Erbia-bearing PWR fuel with > 5 wt% U-235 content

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Franceschini, F.; Lahoda, E. J.; Kucukboyaci, V. N.

    2012-07-01

    The efforts to reduce fuel cycle cost have driven LWR fuel close to the licensed limit in fuel fissile content, 5.0 wt% U-235 enrichment, and the acceptable duty on current Zr-based cladding. An increase in the fuel enrichment beyond the 5 wt% limit, while certainly possible, entails costly investment in infrastructure and licensing. As a possible way to offset some of these costs, the addition of small amounts of Erbia to the UO{sub 2} powder with >5 wt% U-235 has been proposed, so that its initial reactivity is reduced to that of licensed fuel and most modifications to the existingmore » facilities and equipment could be avoided. This paper discusses the potentialities of such a fuel on the US market from a vendor's perspective. An analysis of the in-core behavior and fuel cycle performance of a typical 4-loop PWR with 18 and 24-month operating cycles has been conducted, with the aim of quantifying the potential economic advantage and other operational benefits of this concept. Subsequently, the implications on fuel manufacturing and storage are discussed. While this concept has certainly good potential, a compelling case for its short-term introduction as PWR fuel for the US market could not be determined. (authors)« less

  11. A generalized method for characterization of 235U and 239Pu content using short-lived fission product gamma spectroscopy

    DOE PAGES

    Knowles, Justin R.; Skutnik, Steven E.; Glasgow, David C.; ...

    2016-06-23

    Rapid non-destructive assay methods for trace fissile material analysis are needed in both nuclear forensics and safeguards communities. To address these needs, research at the High Flux Isotope Reactor Neutron Activation Analysis laboratory has developed a generalized non-destructive assay method to characterize materials containing fissile isotopes. This method relies on gamma-ray emissions from short-lived fission products and capitalizes off of differences in fission product yields to identify fissile compositions of trace material samples. Although prior work has explored the use of short-lived fission product gamma-ray measurements, the proposed method is the first to provide a holistic characterization of isotopic identification,more » mass ratios, and absolute mass determination. Successful single fissile isotope mass recoveries of less than 6% error have been conducted on standards of 235U and 239Pu as low as 12 nanograms in less than 10 minutes. Additionally, mixtures of fissile isotope standards containing 235U and 239Pu have been characterized as low as 229 nanograms of fissile mass with less than 12% error. The generalizability of this method is illustrated by evaluating different fissile isotopes, mixtures of fissile isotopes, and two different irradiation positions in the reactor. Furthermore, it is anticipated that this method will be expanded to characterize additional fissile nuclides, utilize various irradiation sources, and account for increasingly complex sample matrices.« less

  12. A generalized method for characterization of 235U and 239Pu content using short-lived fission product gamma spectroscopy

    NASA Astrophysics Data System (ADS)

    Knowles, Justin; Skutnik, Steven; Glasgow, David; Kapsimalis, Roger

    2016-10-01

    Rapid nondestructive assay methods for trace fissile material analysis are needed in both nuclear forensics and safeguards communities. To address these needs, research at the Oak Ridge National Laboratory High Flux Isotope Reactor Neutron Activation Analysis facility has developed a generalized nondestructive assay method to characterize materials containing fissile isotopes. This method relies on gamma-ray emissions from short-lived fission products and makes use of differences in fission product yields to identify fissile compositions of trace material samples. Although prior work has explored the use of short-lived fission product gamma-ray measurements, the proposed method is the first to provide a complete characterization of isotopic identification, mass ratios, and absolute mass determination. Successful single fissile isotope mass recoveries of less than 6% recovery bias have been conducted on standards of 235U and 239Pu as low as 12 ng in less than 10 minutes. Additionally, mixtures of fissile isotope standards containing 235U and 239Pu have been characterized as low as 198 ng of fissile mass with less than 7% recovery bias. The generalizability of this method is illustrated by evaluating different fissile isotopes, mixtures of fissile isotopes, and two different irradiation positions in the reactor. It is anticipated that this method will be expanded to characterize additional fissile nuclides, utilize various irradiation facilities, and account for increasingly complex sample matrices.

  13. A generalized method for characterization of 235U and 239Pu content using short-lived fission product gamma spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Knowles, Justin R.; Skutnik, Steven E.; Glasgow, David C.

    Rapid non-destructive assay methods for trace fissile material analysis are needed in both nuclear forensics and safeguards communities. To address these needs, research at the High Flux Isotope Reactor Neutron Activation Analysis laboratory has developed a generalized non-destructive assay method to characterize materials containing fissile isotopes. This method relies on gamma-ray emissions from short-lived fission products and capitalizes off of differences in fission product yields to identify fissile compositions of trace material samples. Although prior work has explored the use of short-lived fission product gamma-ray measurements, the proposed method is the first to provide a holistic characterization of isotopic identification,more » mass ratios, and absolute mass determination. Successful single fissile isotope mass recoveries of less than 6% error have been conducted on standards of 235U and 239Pu as low as 12 nanograms in less than 10 minutes. Additionally, mixtures of fissile isotope standards containing 235U and 239Pu have been characterized as low as 229 nanograms of fissile mass with less than 12% error. The generalizability of this method is illustrated by evaluating different fissile isotopes, mixtures of fissile isotopes, and two different irradiation positions in the reactor. Furthermore, it is anticipated that this method will be expanded to characterize additional fissile nuclides, utilize various irradiation sources, and account for increasingly complex sample matrices.« less

  14. 50 CFR 622.450 - Gear identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Lobster Fishery of Puerto Rico and the U.S. Virgin Islands § 622.450 Gear identification. (a) Caribbean... Caribbean EEZ must display the official number specified for the vessel by Puerto Rico or the U.S. Virgin... display the official number and color code assigned to the vessel by Puerto Rico or the U.S. Virgin...

  15. Measurement of the ROT effect in the neutron induced fission of 235U in the 0.3 eV resonance at a hot source of polarized neutrons

    NASA Astrophysics Data System (ADS)

    Kopatch, Yuri; Novitsky, Vadim; Ahmadov, Gadir; Gagarsky, Alexei; Berikov, Daniyar; Danilyan, Gevorg; Hutanu, Vladimir; Klenke, Jens; Masalovich, Sergey

    2018-03-01

    The TRI and ROT asymmetries in fission of heavy nuclei have been extensively studied during more than a decade. The effects were first discovered in the ternary fission in a series of experiments performed at the ILL reactor (Grenoble) by a collaboration of Russian and European institutes, and were carefully measured for a number of fissioning nuclei. Later on, the ROT effect has been observed in the emission of prompt gamma rays and neutrons in fission of 235U and 233U, although its value was an order of magnitude smaller than in the α-particle emission from ternary fission. All experiments performed so far are done with cold polarized neutrons, what assumes a mixture of several spin states, the weights of these states being not well known. The present paper describes the first attempt to get "clean" data by performing the measurement of gamma and neutron asymmetries in an isolated resonance of 235U at the POLI instrument of the FRM2 reactor in Garching.

  16. Cytochrome P450 (CYP450) Tests

    MedlinePlus

    ... P450 (CYP450) tests Overview Your doctor may use cytochrome P450 (CYP450) tests to help determine how your body processes (metabolizes) a drug. The human body contains P450 enzymes to process medications. Because of inherited (genetic) traits ...

  17. Distinct 238U/235U ratios and REE patterns in plutonic and volcanic angrites: Geochronologic implications and evidence for U isotope fractionation during magmatic processes

    NASA Astrophysics Data System (ADS)

    Tissot, François L. H.; Dauphas, Nicolas; Grove, Timothy L.

    2017-09-01

    Angrites are differentiated meteorites that formed between 4 and 11 Myr after Solar System formation, when several short-lived nuclides (e.g., 26Al-26Mg, 53Mn-53Cr, 182Hf-182W) were still alive. As such, angrites are prime anchors to tie the relative chronology inferred from these short-lived radionuclides to the absolute Pb-Pb clock. The discovery of variable U isotopic composition (at the sub-permil level) calls for a revision of Pb-Pb ages calculated using an ;assumed; constant 238U/235U ratio (i.e., Pb-Pb ages published before 2009-2010). In this paper, we report high-precision U isotope measurement for six angrite samples (NWA 4590, NWA 4801, NWA 6291, Angra dos Reis, D'Orbigny, and Sahara 99555) using multi-collector inductively coupled plasma mass-spectrometry and the IRMM-3636 U double-spike. The age corrections range from -0.17 to -1.20 Myr depending on the samples. After correction, concordance between the revised Pb-Pb and Hf-W and Mn-Cr ages of plutonic and quenched angrites is good, and the initial (53Mn/55Mn)0 ratio in the Early Solar System (ESS) is recalculated as being (7 ± 1) × 10-6 at the formation of the Solar System (the error bar incorporates uncertainty in the absolute age of Calcium, Aluminum-rich inclusions - CAIs). An uncertainty remains as to whether the Al-Mg and Pb-Pb systems agree in large part due to uncertainties in the Pb-Pb age of CAIs. A systematic difference is found in the U isotopic compositions of quenched and plutonic angrites of +0.17‰. A difference is also found between the rare earth element (REE) patterns of these two angrite subgroups. The δ238U values are consistent with fractionation during magmatic evolution of the angrite parent melt. Stable U isotope fractionation due to a change in the coordination environment of U during incorporation into pyroxene could be responsible for such a fractionation. In this context, Pb-Pb ages derived from pyroxenes fraction should be corrected using the U isotope composition

  18. Studies On Particle-Accompanied Fission Of 252Cf(sf) And 235U(nth,f)

    NASA Astrophysics Data System (ADS)

    Kopatch, Yu N.; Tishchenko, V.; Speransky, M.; Mutterer, M.; Gönnenwein, F.; Jesinger, P.; Gagarski, A. M.; von Kalben, J.; Kojouharov, I.; Lubkiewics, E.; Mezentseva, Z.; Nezvishevsky, V.; Petrov, G. A.; Schaffner, H.; Scharma, H.; Trzaska, W. H.; Wollersheim, H.-J.

    2005-11-01

    In recent multi-parameter studies of spontaneous and thermal neutron induced fission, 252Cf(sf) and 235U(nth,f) respectively, the energies and emission angles of fission fragments and light charged particles were measured. Fragments were detected by an energy and angle sensitive twin ionization chamber while the light charged particles were identified by a series of ΔE-Erest telescopes. Up to Be the light particle isotopes could be disentangled. In addition, in the 252Cf(sf) experiment, gammas emitted by the fragments were analyzed by a pair of large-volume segmented clover Ge detectors. Here the main interest is to study the γ-decay and the anisotropy of gammas emitted by fragments and light particles. On the other hand, the high count rates achieved in the U-experiment performed at the high flux reactor of the ILL, Grenoble, should allow to explore fragment-particle correlations in very rare events like quaternary fission. At the present stage of data evaluation, yields and energy distributions of light particles are available. For the present contribution in particular the yields of Be-isotopes for the two reactions studied are compared and discussed. For 252Cf(sf) these isotopic yields were hitherto not known.

  19. Exploratory study of fission product yields of neutron-induced fission of U 235 ,   U 238 , and Pu 239 at 8.9 MeV

    DOE PAGES

    Bhatia, C.; Fallin, B. F.; Gooden, M. E.; ...

    2015-06-05

    Using dual-fission chambers each loaded with a thick (200–400–mg/cm 2) actinide target of 235,238U or 239Pu and two thin (~10–100–μg/cm 2) reference foils of the same actinide, the cumulative yields of fission products ranging from 92Sr to 147Nd have been measured at E n = 8.9MeV. The 2H(d,n) 3He reaction provided the quasimonoenergetic neutron beam. Here, the experimental setup and methods used to determine the fission product yield (FPY) are described, and results for typically eight high-yield fission products are presented.

  20. 48 CFR 235.006-70 - Manufacturing Technology Program.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Manufacturing Technology... CONTRACTING 235.006-70 Manufacturing Technology Program. In accordance with 10 U.S.C. 2521(d), for acquisitions under the Manufacturing Technology Program— (a) Award all contracts using competitive procedures...

  1. 48 CFR 235.006-70 - Manufacturing Technology Program.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Manufacturing Technology... CONTRACTING 235.006-70 Manufacturing Technology Program. In accordance with 10 U.S.C. 2521(d), for acquisitions under the Manufacturing Technology Program— (a) Award all contracts using competitive procedures...

  2. 48 CFR 235.006-70 - Manufacturing Technology Program.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Manufacturing Technology... CONTRACTING 235.006-70 Manufacturing Technology Program. In accordance with 10 U.S.C. 2521(d), for acquisitions under the Manufacturing Technology Program— (a) Award all contracts using competitive procedures...

  3. 48 CFR 235.006-70 - Manufacturing Technology Program.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Manufacturing Technology... CONTRACTING 235.006-70 Manufacturing Technology Program. In accordance with 10 U.S.C. 2521(d), for acquisitions under the Manufacturing Technology Program— (a) Award all contracts using competitive procedures...

  4. 48 CFR 235.006-70 - Manufacturing Technology Program.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Manufacturing Technology... CONTRACTING 235.006-70 Manufacturing Technology Program. In accordance with 10 U.S.C. 2521(d), for acquisitions under the Manufacturing Technology Program— (a) Award all contracts using competitive procedures...

  5. Thallium, uranium, and {sup 235}U/{sup 238}U ratios in the digestive gland of American lobster (Homarus americanus) from an industrialized harbor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chou, C.L.; Uthe, J.F.

    1995-01-01

    Only a few studies have concentrated on elements such as thallium (TI). Uranium (U) has been studied as a radionuclide of concern in food and the environment. Foodstuffs contain 10-100 ng U{center_dot}{sup -1} with vegetables and cereals contributing most heavily to the daily intake of ca 1.5 ug U. Between 10-30% of ingested U is absorbed, with most being stored in bone. Rainbow trout (onchorynchus mykiss) and longnose sucker (Catostomus catostomus) from a lake with naturally high radioactivity contained < 5 ng U{center_dot}g{sup -1} in the flesh. Trout bone contained 40 ng U{center_dot}g{sup -1}. Higher tissue U concentrations occurred inmore » fish from areas receiving U mining wastes. Bioconcentration factors for bone and flesh were estimated to be low, 118 and 14.7, respectively. This paper describes the Inductively coupled plasma-mass spectrometry (ICP-MS) determination of Tl and U in digestive gland tissue from lobsters captured in the vicinity of Belledune Harbor, New Brunswick, Canada. The harbor is the site of a lead smelter, a fertilizer plant, and a coal-fired power station (the latter due to enter production in late 1993) and thus has the potential of adding significant amounts of Tl to the local marine environment. The accumulation of Tl from water by marine shellfish is low, at least for bivalves, and the accumulated Tl is eliminated in a number of days when the animals are transferred to clean water. Bioconcentration factors for U in finfish ranged from 0.4-17 for larger species. However, because of the high concentrations of various trace elements in lobster digestive gland, its desirability as a foodstuff, and its relatively large size (approximately 20% of the edible tissue yield), we have investigated Tl and U concentrations and {sup 235U}/{sup 238U} ratios in it. 15 refs., 1 fig., 3 tabs.« less

  6. CORRELATIONS OF EFFECTIVE TEMPERATURES FOR NEUTRON SPECTRA EMITTED IN U$sup 235$ AND Pu$sup 239$ FISSION BY FAST AND SLOW NEUTRONS (in Russian)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Smirenkin, G.M.

    1959-12-01

    The method of threshold indicators was used for determining the magnitude of dT/sub ef//dE/sub n/. The fission neutrons were produced by fast and slow neutron bombardment. tron bombardment was accomplished in a paraffin block. Hollow metallic U/sup 235/ (90% enriched) and Pu/sup 239/ specimens with 50 mm outside diameters and 10 mm thick contained the threshold activator Ag/sup 107/(n,2n)Ag/sup 106m/. Measurements were made of the neutron flux above the threshold (9.5 Mev) of the Ag/sup 107/(n,2n)Ag/sup 106m/ reaction and the number of fission in the sphere (N/sub gamma /). The final data showed that for U/sup 235/ dT/sub ef//dE/sub n/more » = 0.008 plus or minus 0.004 and for Pu/sup 239/ dT/ sub ef/ /dE/sub n/ = tron fission distributions explain part of the error of the measurement. (R.V.J.)« less

  7. Neutron Capture Cross Sections and Gamma Emission Spectra from Neutron Capture on 234,236,238U Measured with DANCE

    NASA Astrophysics Data System (ADS)

    Ullmann, J. L.; Mosby, S.; Bredeweg, T. A.; Couture, A. J.; Haight, R. C.; Jandel, M.; Kawano, T.; O'Donnell, J. M.; Rundberg, R. S.; Vieira, D. J.; Wilhelmy, J. B.; Wu, C.-Y.; Becker, J. A.; Chyzh, A.; Baramsai, B.; Mitchell, G. E.; Krticka, M.

    2014-05-01

    A new measurement of the 238U(n, γ) cross section using a thin 48 mg/cm2 target was made using the DANCE detector at LANSCE over the energy range from 10 eV to 500 keV. The results confirm earlier measurements. Measurements of the gamma-ray emission spectra were also made for 238U(n, γ) as well as 234,236U(n, γ). These measurements help to constrain the radiative strength function used in the cross-section calculations.

  8. A Study of the Gaseous Diffusion Plant for U$sup 235$ Enrichment; STUDI SU GLI IMPIANTI A DISSUFIONE GASOSA PER L'ARRICCHIMENTO DELL' U$sup 23$$sup 5$

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Perona, G.

    1959-04-01

    The gaseous diffusion process for the enrichment of U/sup 235/ is discussed. The physical principles of the process, the cascades and selection of the pressures, temperatures, and barriers are described. The gaseous diffusion plant is discussed with a consideration of the preliminary calculation of the plant yields the diffusor, operating temperature, layout of the plants control, and cost analysis. The chemical properties of UF/sub 6/, its preparation and purification, and the transformation of UF/sub 6/ to UF/sub 4/ are reviewed. (J.S.R)

  9. Preliminary results of calculations for heavy-water nuclear-power-plant reactors employing 235U, 233U, and 232Th as a fuel and meeting requirements of a nonproliferation of nuclear weapons

    NASA Astrophysics Data System (ADS)

    Ioffe, B. L.; Kochurov, B. P.

    2012-02-01

    A physical design is developed for a gas-cooled heavy-water nuclear reactor intended for a project of a nuclear power plant. As a fuel, the reactor would employ thorium with a small admixture of enriched uranium that contains not more than 20% of 235U. It operates in the open-cycle mode involving 233U production from thorium and its subsequent burnup. The reactor meets the conditions of a nonproliferation of nuclear weapons: the content of fissionable isotopes in uranium at all stages of the process, including the final one, is below the threshold for constructing an atomic bomb, the amount of product plutonium being extremely small.

  10. On the Quality of ENSDF {gamma}-Ray Intensity Data for {gamma}-Ray Spectrometric Determination of Th and U and Their Decay Series Disequilibria, in the Assessment of the Radiation Dose Rate in Luminescence Dating of Sediments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Corte, Frans de; Vandenberghe, Dimitri; Wispelaere, Antoine de

    In luminescence dating of sediments, one of the most interesting tools for the determination of the annual radiation dose is Ge {gamma}-ray spectrometry. Indeed, it yields information on both the content of the radioelements K, Th, and U, and on the occurrence - in geological times - of disequilibria in the Th and U decay series. In the present work, two methodological variants of the {gamma}-spectrometric analysis were tested, which largely depend on the quality of the nuclear decay data involved: (1) a parametric calibration of the sediment measurements, and (2) the correction for the heavy spectral interference of themore » 226Ra 186.2 keV peak by 235U at 185.7 keV. The performance of these methods was examined via the analysis of three Certified Reference Materials, with the introduction of {gamma}-ray intensity data originating from ENSDF. Relevant conclusions were drawn as to the accuracy of the data and their uncertainties quoted.« less

  11. L x-ray production cross sections in Th and U at 17.8, 25.8 and 46.9 keV photon energies

    NASA Astrophysics Data System (ADS)

    Kumar, Ajay; Puri, Sanjiv; Shahi, J. S.; Garg, M. L.; Mehta, D.; Singh, Nirmal

    2001-02-01

    The L x-ray production (XRP) differential cross sections in Th and U have been measured at the 17.8 keV incident photon energy (E_L3keV incident photon energies (E_L1keV photon energies, deduced assuming isotropic emission of the L x-rays, are found to be in good agreement with those evaluated using the most reliable theoretical values of Li (i = 1,2,3) subshell photoionization cross sections, fluorescence yields, x-ray emission rates and Coster-Kronig transition probabilities.

  12. Energy spectrum of sputtered uranium - A new technique

    NASA Technical Reports Server (NTRS)

    Weller, R. A.; Tombrello, T. A.

    1978-01-01

    The fission track technique for detecting U-235 has been used in conjunction with a mechanical time-of-flight spectrometer in order to measure the energy spectrum in the region 1 eV to 1 keV of material sputtered from a 93% enriched U-235 foil by 80 keV Ar-40(+) ions. The spectrum was found to exhibit a peak in the region 2-4 eV and to decrease approximately as E exp -1.77 for E not less than 100 eV. The design, construction and resolution of the mechanical spectrometer are discussed and comparisons are made between the data and the predictions of the random collision cascade model of sputtering.

  13. 24 CFR 235.1220 - Processing section 235(r) mortgages under the direct endorsement program.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... under the direct endorsement program. 235.1220 Section 235.1220 Housing and Urban Development... National Housing Act Eligibility Requirements; Direct Endorsement § 235.1220 Processing section 235(r) mortgages under the direct endorsement program. The regulations containing the requirements which a mortgage...

  14. Evaluations of Energy Spectra of Neutrons Emitted Promptly in Neutron-induced Fission of 235 U and 239 Pu

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Neudecker, Denise; Talou, Patrick; Kawano, Toshihiko

    The energy spectra of neutrons emitted promptly in the neutron-induced fission reactions of 235U and 239Pu were re-evaluated for ENDF/B-VIII.0. The evaluations presented here are based on a careful modeling of all relevant physics processes, an extensive analysis of experimental data and a detailed quantification of pertinent uncertainties. Energy spectra of neutrons emitted in up to fourth chance fission are considered and both compound and pre-equilibrium processes are included. Also, important nuclear model parameters, such as the average total kinetic energy of the fission fragments and the multiple chance fission probabilities, and their uncertainties are estimated based on experimental knowledge,more » model information and evaluated data. In addition to experimental information already available for ENDF/B-VII.1, these new evaluations make use of recently published experimental data either of high precision or spanning a broad incident energy range, information on legacy measurements explaining discrepancies and recently measured data of the average total kinetic energy as a function of incident neutron energy. The resulting evaluated data and covariances agree well with the experimental database used for the evaluation. However, the evaluated spectra are softer than the 235U and 239Pu ENDF/B-VII.1, JENDL-4.0 and JEFF-3.2 evaluations for incident neutron energies E inc ≤ 1.5 MeV and E inc ≤ 5 MeV, respectively. For E inc > 5 MeV, the evaluated spectra show structures due to the improved modeling which are not present in ENDF/B-VII.1 and JEFF-3.2 but can be observed in JENDL-4.0 evaluations. Part of these new evaluations were adopted for ENDF/B-VIII.0, while the ENDF/B-VII.1 239Pu PFNS was retained for E inc ≤ 5 MeV awaiting more conclusive experimental evidence.« less

  15. Evaluations of Energy Spectra of Neutrons Emitted Promptly in Neutron-induced Fission of 235 U and 239 Pu

    DOE PAGES

    Neudecker, Denise; Talou, Patrick; Kawano, Toshihiko; ...

    2018-02-01

    The energy spectra of neutrons emitted promptly in the neutron-induced fission reactions of 235U and 239Pu were re-evaluated for ENDF/B-VIII.0. The evaluations presented here are based on a careful modeling of all relevant physics processes, an extensive analysis of experimental data and a detailed quantification of pertinent uncertainties. Energy spectra of neutrons emitted in up to fourth chance fission are considered and both compound and pre-equilibrium processes are included. Also, important nuclear model parameters, such as the average total kinetic energy of the fission fragments and the multiple chance fission probabilities, and their uncertainties are estimated based on experimental knowledge,more » model information and evaluated data. In addition to experimental information already available for ENDF/B-VII.1, these new evaluations make use of recently published experimental data either of high precision or spanning a broad incident energy range, information on legacy measurements explaining discrepancies and recently measured data of the average total kinetic energy as a function of incident neutron energy. The resulting evaluated data and covariances agree well with the experimental database used for the evaluation. However, the evaluated spectra are softer than the 235U and 239Pu ENDF/B-VII.1, JENDL-4.0 and JEFF-3.2 evaluations for incident neutron energies E inc ≤ 1.5 MeV and E inc ≤ 5 MeV, respectively. For E inc > 5 MeV, the evaluated spectra show structures due to the improved modeling which are not present in ENDF/B-VII.1 and JEFF-3.2 but can be observed in JENDL-4.0 evaluations. Part of these new evaluations were adopted for ENDF/B-VIII.0, while the ENDF/B-VII.1 239Pu PFNS was retained for E inc ≤ 5 MeV awaiting more conclusive experimental evidence.« less

  16. Evaluations of Energy Spectra of Neutrons Emitted Promptly in Neutron-induced Fission of 235U and 239Pu

    NASA Astrophysics Data System (ADS)

    Neudecker, D.; Talou, P.; Kawano, T.; Kahler, A. C.; White, M. C.; Taddeucci, T. N.; Haight, R. C.; Kiedrowski, B.; O'Donnell, J. M.; Gomez, J. A.; Kelly, K. J.; Devlin, M.; Rising, M. E.

    2018-02-01

    The energy spectra of neutrons emitted promptly in the neutron-induced fission reactions of 235U and 239Pu were re-evaluated for ENDF/B-VIII.0. These evaluations are based on a careful modeling of all relevant physics processes, an extensive analysis of experimental data and a detailed quantification of pertinent uncertainties. Energy spectra of neutrons emitted in up to fourth chance fission are considered and both compound and pre-equilibrium processes are included. Also, important nuclear model parameters, such as the average total kinetic energy of the fission fragments and the multiple chance fission probabilities, and their uncertainties are estimated based on experimental knowledge, model information and evaluated data. In addition to experimental information already available for ENDF/B-VII.1, these new evaluations make use of recently published experimental data either of high precision or spanning a broad incident energy range, information on legacy measurements explaining discrepancies and recently measured data of the average total kinetic energy as a function of incident neutron energy. The resulting evaluated data and covariances agree well with the experimental database used for the evaluation. However, the evaluated spectra are softer than the 235U and 239Pu ENDF/B-VII.1, JENDL-4.0 and JEFF-3.2 evaluations for incident neutron energies Einc ≤ 1.5 MeV and Einc ≤ 5 MeV, respectively. For Einc > 5 MeV, the evaluated spectra show structures due to the improved modeling which are not present in ENDF/B-VII.1 and JEFF-3.2 but can be observed in JENDL-4.0 evaluations. Part of these new evaluations were adopted for ENDF/B-VIII.0, while the ENDF/B-VII.1 239Pu PFNS was retained for Einc ≤ 5 MeV awaiting more conclusive experimental evidence.

  17. An Empirical Method for Determining 234U Percentage

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miko, David K.

    2015-11-02

    When isotopic information for uranium is provided, the concentration of 234U is frequently neglected. Often the isotopic content is given as a percentage of 235U with the assumption that the remainder consists of 238U. In certain applications, such as heat output, the concentration of 234U can be a significant contributing factor. For situations where only the 235U and 238U values are given, a simple way to calculate the 234U component would be beneficial. The approach taken here is empirical. A series of uranium standards with varying enrichments were analyzed. The 234U and 235U data were fit using a second ordermore » polynomial.« less

  18. 7 CFR 500.6 - Gambling.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Gambling. 500.6 Section 500.6 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.6 Gambling. Participating in games...

  19. 7 CFR 500.6 - Gambling.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Gambling. 500.6 Section 500.6 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.6 Gambling. Participating in games...

  20. 7 CFR 500.6 - Gambling.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Gambling. 500.6 Section 500.6 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.6 Gambling. Participating in games...

  1. 7 CFR 500.6 - Gambling.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Gambling. 500.6 Section 500.6 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.6 Gambling. Participating in games...

  2. 7 CFR 500.6 - Gambling.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Gambling. 500.6 Section 500.6 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.6 Gambling. Participating in games...

  3. 7 CFR 500.10 - Pets.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Pets. 500.10 Section 500.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.10 Pets. Pets brought upon USNA...

  4. 7 CFR 500.10 - Pets.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Pets. 500.10 Section 500.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.10 Pets. Pets brought upon USNA...

  5. 7 CFR 500.10 - Pets.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Pets. 500.10 Section 500.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.10 Pets. Pets brought upon USNA...

  6. 7 CFR 500.10 - Pets.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Pets. 500.10 Section 500.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.10 Pets. Pets brought upon USNA...

  7. 7 CFR 500.10 - Pets.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Pets. 500.10 Section 500.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.10 Pets. Pets brought upon USNA...

  8. A High Accuracy Measurement of the Nuclear Decay of 235mU and Search for the Nuclear Decay of 229mTh

    NASA Astrophysics Data System (ADS)

    Ponce, Francisco

    Among all nuclear decays, there exist two isomeric states with very low-energy that belong to . {229}Th (7.8 ± 0.5 eV) and . {235}U (76.8 ± 0.5 eV) . Of particular interest is . {229}Th, because the decay energy is in the ultraviolet, and therefore in the range of modern tunable lasers. The isomer can potentially be used as the basis for a nuclear clock that is expected to be two orders of magnitude more precise than atomic clocks. However, the . {229m}Th nuclear decay energy is not sufficiently well known to design the necessary laser system for a nuclear clock. This work describes the development of a new technique using superconducting tunnel junction (STJ) detectors to directly measure the nuclear decay of low-energy isomers with a high level of accuracy. The strength of the technique is demonstrated by measuring the decay energy of the . {235}U isomer at 76.737 ± 0.018 eV. Over an order of magnitude more accurate than the current literature value. The technique is then applied to detect the transition in . {229m}Th directly and measure its energy with comparable accuracy. These experiments are unsuccessful and are discussed in light of the recent measurement of the . {229m}Th half-life of 7 ± \\SI{1}{\\micro\\second}.

  9. Investigating Prompt Fission Neutron Emission from 235U(n,f) in the Resolved Resonance Region

    NASA Astrophysics Data System (ADS)

    Göök, Alf; Hambsch, Franz-Josef; Oberstedt, Stephan

    2016-03-01

    Investigations of prompt emission in fission is of importance in understanding the fission process in general and the sharing of excitation energy among the fission fragments in particular. Experimental activities at IRMM on prompt neutron emission from fission in response to OECD/NEA nuclear data requests is presented in this contribution. Main focus lies on currently on-going investigations of prompt neutron emission from the reaction 235U(n,f) in the region of the resolved resonances. For this reaction strong fluctuations of fission fragment mass distributions and mean total kinetic energy have been observed [Nucl. Phys. A 491, 56 (1989)] as a function of incident neutron energy in the resonance region. In addition fluctuations of prompt neutron multiplicities were also observed [Phys. Rev. C 13, 195 (1976)]. The goal of the present study is to verify the current knowledge of prompt neutron multiplicity fluctuations and to study correlations with fission fragment properties.

  10. Dosimetry of high-energy electron linac produced photoneutrons and the bremsstrahlung gamma-rays using TLD-500 and TLD-700 dosimeter pairs

    NASA Astrophysics Data System (ADS)

    Mukherjee, Bhaskar; Makowski, Dariusz; Simrock, Stefan

    2005-06-01

    The neutron and gamma doses are crucial to interpreting the radiation effects in microelectronic devices operating in a high-energy accelerator environment. This report highlights a method for an accurate estimation of photoneutron and the accompanying bremsstrahlung (gamma) doses produced by a 450 MeV electron linear accelerator (linac) operating in pulsed mode. The principle is based on the analysis of thermoluminescence glow-curves of TLD-500 (Aluminium Oxide) and TLD-700 (Lithium Fluoride) dosimeter pairs. The gamma and fast neutron response of the TLD-500 and TLD-700 dosimeter pairs were calibrated with a 60Co (gamma) and a 241Am-Be (α, n) neutron standard-source, respectively. The Kinetic Energy Released in Materials (kerma) conversion factor for photoneutrons was evaluated by folding the neutron kerma (dose) distribution in 7LiF (the main component of the TLD-700 dosimeter) with the energy spectra of the 241Am-Be (α, n) neutrons and electron accelerator produced photoneutrons. The neutron kerma conversion factors for 241Am-Be neutrons and photoneutrons were calculated to be 2.52×10 -3 and 1.37×10 -3 μGy/a.u. respectively. The bremsstrahlung (gamma) dose conversion factor was evaluated to be 7.32×10 -4 μGy/a.u. The above method has been successfully utilised to assess the photoneutron and bremsstrahlung doses from a 450 MeV electron linac operating at DESY Research Centre in Hamburg, Germany.

  11. 28 CFR 500.1 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Definitions. 500.1 Section 500.1 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE GENERAL MANAGEMENT AND ADMINISTRATION GENERAL DEFINITIONS § 500.1 Definitions. As used in this chapter, (a) The Warden means the chief executive officer of a U.S...

  12. 24 CFR 235.1200 - Authority.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Authority. 235.1200 Section 235... DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MORTGAGE... § 235.1200 Authority. In accordance with the authority contained in section 235(r) of the National...

  13. A Nonlinear Model Predictive Control Algorithm for Obstacle Avoidance in Autonomous Ground Vehicles within Unknown Environments

    DTIC Science & Technology

    2015-04-24

    xs , ys , xe , ye ) double EndPo in t s [L...Distribution Statement A. Approved for public release. #26161 350 400 450 100 150 200 250 300 350 400 450 500 550 600 x (m) y (m ) Start Target U0 = 10...longitudinal speed 350 400 450 100 150 200 250 300 350 400 450 500 550 600 x (m) y (m ) Start Target (a) Trajectory 0 5 10 15 0 1 t (s) f ( U0 = 30

  14. 7 CFR 500.5 - Nuisances.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Nuisances. 500.5 Section 500.5 Agriculture Regulations... NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.5 Nuisances. (a) The use of loud... creation of other noises of a decibel level high enough to be heard outside of the USNA is prohibited. ...

  15. 13 CFR 500.103 - Offices.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Offices. 500.103 Section 500.103 Business Credit and Assistance EMERGENCY OIL AND GAS GUARANTEED LOAN BOARD EMERGENCY OIL AND GAS GUARANTEED LOAN PROGRAM Board Procedures § 500.103 Offices. The principal offices of the Board are in the U.S...

  16. Transcriptome analysis and identification of P450 genes relevant to imidacloprid detoxification in Bradysia odoriphaga.

    PubMed

    Chen, Chengyu; Wang, Cuicui; Liu, Ying; Shi, Xueyan; Gao, Xiwu

    2018-02-07

    Pesticide tolerance poses many challenges for pest control, particularly for destructive pests such as Bradysia odoriphaga. Imidacloprid has been used to control B. odoriphaga since 2013, however, imidacloprid resistance in B. odoriphaga has developed in recent years. Identifying actual and potential genes involved in detoxification metabolism of imidacloprid could offer solutions for controlling this insect. In this study, RNA-seq was used to explore differentially expressed genes in B. odoriphaga that respond to imidacloprid treatment. Differential expression data between imidacloprid treatment and the control revealed 281 transcripts (176 with annotations) showing upregulation and 394 transcripts (235 with annotations) showing downregulation. Among them, differential expression levels of seven P450 unigenes were associated with imidacloprid detoxification mechanism, with 4 unigenes that were upregulated and 3 unigenes that were downregulated. The qRT-PCR results of the seven differential expression P450 unigenes after imidacloprid treatment were consistent with RNA-Seq data. Furthermore, oral delivery mediated RNA interference of these four upregulated P450 unigenes followed by an insecticide bioassay significantly increased the mortality of imidacloprid-treated B. odoriphaga. This result indicated that the four upregulated P450s are involved in detoxification of imidacloprid. This study provides a genetic basis for further exploring P450 genes for imidacloprid detoxification in B. odoriphaga.

  17. Prompt fission neutron spectra from fission induced by 1 to 8 MeV neutrons on U235 and Pu239 using the double time-of-flight technique

    NASA Astrophysics Data System (ADS)

    Noda, S.; Haight, R. C.; Nelson, R. O.; Devlin, M.; O'Donnell, J. M.; Chatillon, A.; Granier, T.; Bélier, G.; Taieb, J.; Kawano, T.; Talou, P.

    2011-03-01

    Prompt fission neutron spectra from U235 and Pu239 were measured for incident neutron energies from 1 to 200 MeV at the Weapons Neutron Research facility (WNR) of the Los Alamos Neutron Science Center, and the experimental data were analyzed with the Los Alamos model for the incident neutron energies of 1-8 MeV. A CEA multiple-foil fission chamber containing deposits of 100 mg U235 and 90 mg Pu239 detected fission events. Outgoing neutrons were detected by the Fast Neutron-Induced γ-Ray Observer array of 20 liquid organic scintillators. A double time-of-flight technique was used to deduce the neutron incident energies from the spallation target and the outgoing energies from the fission chamber. These data were used for testing the Los Alamos model, and the total kinetic energy parameters were optimized to obtain a best fit to the data. The prompt fission neutron spectra were also compared with the Evaluated Nuclear Data File (ENDF/B-VII.0). We calculate average energies from both experimental and calculated fission neutron spectra.

  18. Benchmark Gamma Spectroscopy Measurements of Uranium Hexafluoride in Aluminmum Pipe with a Sodium Iodide Detector

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    March-Leuba, Jose A; Uckan, Taner; Gunning, John E

    2010-01-01

    factors, the experimental 186 keV counts in the test geometry were extrapolated to the expected GCEP geometry, and calibration curves were developed. A unique method to analyze the measurement was also developed that separated the detector spectrum into the five detectable decay gamma rays emitted by {sup 235}U in the 120 to 200 keV energy range. This analysis facilitated the assignment of a consistent value for the detector counts originating from {sup 235}U decays at 186 keV. This value is also more accurate because it includes the counts from gamma energies other than 186 keV, which results in increased counting statistics for the same measurement time. The 186 keV counts expected as a function of pressure and enrichment are presented in the body of this report. The main result of this research is a calibration factor for 4-inch and 8-inch schedule 40 aluminum pipes. For 4-inch pipes, the {sup 235}U density is 0.62 {sup 235}U g/m{sup 3} per each measured 186 keV count.« less

  19. Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, Matthew; Bredeweg, Todd; Fowler, Malcolm; Vieira, David; Wilhelmy, Jerry; Tonchev, Anton; Stoyer, Mark; Bhike, Megha; Finch, Sean; Krishichayan, Fnu; Tornow, Werner

    2017-09-01

    The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi- monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combi- nation of fission counting using specially designed dual-fission chambers and -ray counting. Each dual-fission chamber is a back-to-back ioniza- tion chamber encasing an activation target in the center with thin de- posits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activa- tion target with no reference to the fission cross-section, thus reducing uncertainties. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of 2 months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6 and 14.8 MeV. New data in the second chance fission region of 5.5 - 9 MeV are included. Work performed for the U.S. Department of Energy by Los Alamos National Security, LLC under Contract DE-AC52-06NA25396.

  20. 50 CFR 622.450 - Gear identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Spiny Lobster Fishery of Puerto Rico and the U.S. Virgin Islands § 622.450 Gear identification. (a) Caribbean... Islands so as to be easily identified. Traps used in the Caribbean spiny lobster fishery that are fished...

  1. Evaluation of the 239 Pu prompt fission neutron spectrum induced by neutrons of 500 keV and associated covariances

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Neudecker, D.; Talou, P.; Kawano, T.

    2015-08-01

    We present evaluations of the prompt fission neutron spectrum (PFNS) of (PU)-P-239 induced by 500 keV neutrons, and associated covariances. In a previous evaluation by Talon et al. (2010), surprisingly low evaluated uncertainties were obtained, partly due to simplifying assumptions in the quantification of uncertainties from experiment and model. Therefore, special emphasis is placed here on a thorough uncertainty quantification of experimental data and of the Los Alamos model predicted values entering the evaluation. In addition, the Los Alamos model was extended and an evaluation technique was employed that takes into account the qualitative differences between normalized model predicted valuesmore » and experimental shape data These improvements lead to changes in the evaluated PENS and overall larger evaluated uncertainties than in the previous work. However, these evaluated uncertainties are still smaller than those obtained in a statistical analysis using experimental information only, due to strong model correlations. Hence, suggestions to estimate model defect uncertainties are presented. which lead to more reasonable evaluated uncertainties. The calculated k(eff) of selected criticality benchmarks obtained with these new evaluations agree with each other within their uncertainties despite the different approaches to estimate model defect uncertainties. The k(eff) one standard deviations overlap with some of those obtained using ENDF/B-VILl, albeit their mean values are further away from unity. Spectral indexes for the Jezebel critical assembly calculated with the newly evaluated PFNS agree with the experimental data for selected (n,) and (n,f) reactions, and show improvements for highenergy threshold (n,2n) reactions compared to ENDF/B-VII.l. (C) 2015 Elsevier B.V. All rights reserved.« less

  2. Dynamics of melt generation beneath mid-ocean ridge axes: Theoretical analysis based on 238- 230Th- 226Ra and 235U- 231Pa disequilibria

    NASA Astrophysics Data System (ADS)

    Qin, Zhenwei

    1993-04-01

    Although slow melting favors the generation of basaltic melt from a mantle matrix with large radioactive disequilibrium between two actinide nuclides ( MCKENZIE, 1985a), it results in long residence time in a magma chamber, during which the disequilibrium may be removed. An equilibrium melting model modified after MCKENZIE (1985a) is presented here which suggests that, for a given actinide parent-daughter pair, there exists a specific melting rate at which disequilibrium between these two nuclides reaches its maximum. This melting rate depends on the decay constant of the daughter nuclide concerned and the magma chamber volume scaled to that of its source. For a given scaled chamber size, large radioactive disequilibrium between two actinide nuclides in basalts will be observed if the melting rate is such that the residence time of the magma in the chamber is comparable to the mean life of the daughter nuclide. With a chamber size 1% in volume of the melting source, the melting rates at which maximum disequilibrium in basalts is obtained are 10 -7, 2 × 10 -7 and 3 × 10 -6y-1, respectively, for 238U- 230Th, 235U- 231Pa and 230Th- 226Ra. This implies that, while large disequilibrium between 238U- 230Th and between 235U- 231Pa may occur together, large 230Th- 226Ra disequilibrium will not coexist with large 238U- 230Th disequilibrium, consistent with some observations. The active mantle melting zone which supplies melt to a ridge axis is inferred to be only about 10 km thick and 50 km wide. The fraction of melt present in such a mantle source at any time is about 0.01 and 0.04, respectively, if melting rate is 10 -7 and 10 -6 y -1. The corresponding residence time of the residual melt in the matrix is 10 5 and 4 × 10 4y.

  3. Uranium, radium and thorium in soils with high-resolution gamma spectroscopy, MCNP-generated efficiencies, and VRF non-linear full-spectrum nuclide shape fitting

    NASA Astrophysics Data System (ADS)

    Metzger, Robert; Riper, Kenneth Van; Lasche, George

    2017-09-01

    A new method for analysis of uranium and radium in soils by gamma spectroscopy has been developed using VRF ("Visual RobFit") which, unlike traditional peak-search techniques, fits full-spectrum nuclide shapes with non-linear least-squares minimization of the chi-squared statistic. Gamma efficiency curves were developed for a 500 mL Marinelli beaker geometry as a function of soil density using MCNP. Collected spectra were then analyzed using the MCNP-generated efficiency curves and VRF to deconvolute the 90 keV peak complex of uranium and obtain 238U and 235U activities. 226Ra activity was determined either from the radon daughters if the equilibrium status is known, or directly from the deconvoluted 186 keV line. 228Ra values were determined from the 228Ac daughter activity. The method was validated by analysis of radium, thorium and uranium soil standards and by inter-comparison with other methods for radium in soils. The method allows for a rapid determination of whether a sample has been impacted by a man-made activity by comparison of the uranium and radium concentrations to those that would be expected from a natural equilibrium state.

  4. 46 CFR 108.235 - Construction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Construction. 108.235 Section 108.235 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Helicopter Facilities § 108.235 Construction. (a) Each helicopter deck must be...

  5. 46 CFR 108.235 - Construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Construction. 108.235 Section 108.235 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Helicopter Facilities § 108.235 Construction. (a) Each helicopter deck must be...

  6. 46 CFR 108.235 - Construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Construction. 108.235 Section 108.235 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Helicopter Facilities § 108.235 Construction. (a) Each helicopter deck must be...

  7. 7 CFR 235.3 - Administration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Administration. 235.3 Section 235.3 Agriculture... CHILD NUTRITION PROGRAMS STATE ADMINISTRATIVE EXPENSE FUNDS § 235.3 Administration. (a) Within the Department, FNS shall act on behalf of the Department in the administration of the program for payment to...

  8. 7 CFR 235.3 - Administration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 4 2012-01-01 2012-01-01 false Administration. 235.3 Section 235.3 Agriculture... CHILD NUTRITION PROGRAMS STATE ADMINISTRATIVE EXPENSE FUNDS § 235.3 Administration. (a) Within the Department, FNS shall act on behalf of the Department in the administration of the program for payment to...

  9. 7 CFR 235.3 - Administration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 4 2014-01-01 2014-01-01 false Administration. 235.3 Section 235.3 Agriculture... CHILD NUTRITION PROGRAMS STATE ADMINISTRATIVE EXPENSE FUNDS § 235.3 Administration. (a) Within the Department, FNS shall act on behalf of the Department in the administration of the program for payment to...

  10. 7 CFR 235.3 - Administration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 4 2013-01-01 2013-01-01 false Administration. 235.3 Section 235.3 Agriculture... CHILD NUTRITION PROGRAMS STATE ADMINISTRATIVE EXPENSE FUNDS § 235.3 Administration. (a) Within the Department, FNS shall act on behalf of the Department in the administration of the program for payment to...

  11. 21 CFR 172.235 - Morpholine.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Morpholine. 172.235 Section 172.235 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Coatings, Films and Related Substances § 172.235...

  12. Vector representation as a tool for detecting characteristic uranium peaks

    NASA Astrophysics Data System (ADS)

    Forney, Anne Marie

    Vector representation is found as a viable tool for identifying the presence of and determining the difference between enriched and naturally occurring uranium. This was accomplished through the isolation of two regions of interest around the uranium-235 (235U) gamma emission at 186 keV and the uranium-238 (238U) gamma emission at 1001 keV. The uranium 186 keV peak is used as a meter for uranium enrichment, and events from this emission occurred more frequently with the increase of the 235U composition. Spectra were taken with the use of a high purity germanium detector in series with a multi-channel analyzer (MCA) and Maestro 32, a MCA emulator and spectral software. The vector representation method was used to compare two spectra by taking their dot product. The output from this method is an angle, which represents the similarity and contrast between the two spectra. When the angle is close to zero the spectra are similar, and as the angle approaches 90 degrees the spectral agreement decreases. The angles were calculated and compared in Microsoft Excel. A 49 % enriched uranyl acetate source containing both gamma emissions from 235U and 238U was used as a reference source to which all spectra were compared. Two other uranium sources were used within this project: a 100.2 nCi highly-enriched uranium source with 97.7 % 235U by weight, and a piece of uranium ore with an approximate exposure rate of 0.2 mR/h (51.5 nC/kg/h) at 1 cm. These two uranium sources provided different ratios of 235U to 238U, leading to different ratios of the 186 keV and 1001 keV peaks. To test the limits of the vector representation method, various source configurations were used. These included placing the source directly on top of the detector, using two distances for the source from the detector, using the source in addition to cobalt-60, and finally two distances for the source from the detector with a one centimeter lead shield. The two distances from the detector without the shielding

  13. 7 CFR 500.3 - Preservation of property.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Preservation of property. 500.3 Section 500.3 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.3 Preservation...

  14. 49 CFR 450.16 - Withdrawal of delegation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS GENERAL Procedure for Delegation to Approval Authorities § 450.16 Withdrawal of delegation. (a) The Chief, Office of Operating and Environmental Standards (CG-OES... of Operating and Environmental Standards (CG-OES), U.S. Coast Guard gives to the Approval Authority...

  15. 49 CFR 450.16 - Withdrawal of delegation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS GENERAL Procedure for Delegation to Approval Authorities § 450.16 Withdrawal of delegation. (a) The Chief, Office of Operating and Environmental Standards (CG-OES... of Operating and Environmental Standards (CG-OES), U.S. Coast Guard gives to the Approval Authority...

  16. 49 CFR 450.16 - Withdrawal of delegation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS GENERAL Procedure for Delegation to Approval Authorities § 450.16 Withdrawal of delegation. (a) The Chief, Office of Operating and Environmental Standards (CG-522... of Operating and Environmental Standards (CG-522), U.S. Coast Guard gives to the Approval Authority...

  17. 49 CFR 450.16 - Withdrawal of delegation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS GENERAL Procedure for Delegation to Approval Authorities § 450.16 Withdrawal of delegation. (a) The Chief, Office of Operating and Environmental Standards (CG-OES... of Operating and Environmental Standards (CG-OES), U.S. Coast Guard gives to the Approval Authority...

  18. 49 CFR 450.16 - Withdrawal of delegation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS GENERAL Procedure for Delegation to Approval Authorities § 450.16 Withdrawal of delegation. (a) The Chief, Office of Operating and Environmental Standards (CG-522... of Operating and Environmental Standards (CG-522), U.S. Coast Guard gives to the Approval Authority...

  19. Nuclear reactor for breeding U.sup.233

    DOEpatents

    Bohanan, Charles S.; Jones, David H.; Raab, Jr., Harry F.; Radkowsky, Alvin

    1976-01-01

    A light-water-cooled nuclear reactor capable of breeding U.sup.233 for use in a light-water breeder reactor includes physically separated regions containing U.sup.235 fissile material and U.sup.238 fertile material and Th.sup.232 fertile material and Pu.sup.239 fissile material, if available. Preferably the U.sup.235 fissile material and U.sup.238 fertile material are contained in longitudinally movable seed regions and the Pu.sup.239 fissile material and Th.sup.232 fertile material are contained in blanket regions surrounding the seed regions.

  20. 45 CFR 235.110 - Fraud.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Fraud. 235.110 Section 235.110 Public Welfare... PROGRAMS § 235.110 Fraud. State plan requirements: A State plan under title I, IV-A, X, XIV, or XVI of the Social Security Act must provide: (a) That the State agency will establish and maintain: (1) Methods and...

  1. 24 CFR 5.500 - Applicability.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Development Act of 1980, as amended (42 U.S.C. 1436a). Section 214 prohibits HUD from making financial... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Applicability. 5.500 Section 5.500 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development GENERAL...

  2. Yields of short-lived fission products produced following {sup 235}U(n{sub th},f)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tipnis, S.V.; Campbell, J.M.; Couchell, G.P.

    1998-08-01

    Measurements of gamma-ray spectra, following the thermal neutron fission of {sup 235}U have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10thinsp000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with themore » recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for the cases of short-lived fission products with lifetimes of the order of fractions of a second or a few seconds. Independent yields of many of these isotopes have rather large uncertainties, some of which have been reduced by the present study. {copyright} {ital 1998} {ital The American Physical Society}« less

  3. 7 CFR 500.12 - Weapons and explosives.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Weapons and explosives. 500.12 Section 500.12... OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.12 Weapons and... weapons, or explosives, either openly or concealed, except for authorized official purposes. (b) No person...

  4. 7 CFR 500.12 - Weapons and explosives.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Weapons and explosives. 500.12 Section 500.12... OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.12 Weapons and... weapons, or explosives, either openly or concealed, except for authorized official purposes. (b) No person...

  5. 7 CFR 500.12 - Weapons and explosives.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Weapons and explosives. 500.12 Section 500.12... OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.12 Weapons and... weapons, or explosives, either openly or concealed, except for authorized official purposes. (b) No person...

  6. 7 CFR 500.12 - Weapons and explosives.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Weapons and explosives. 500.12 Section 500.12... OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.12 Weapons and... weapons, or explosives, either openly or concealed, except for authorized official purposes. (b) No person...

  7. 7 CFR 500.12 - Weapons and explosives.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Weapons and explosives. 500.12 Section 500.12... OF AGRICULTURE NATIONAL ARBORETUM Conduct on U.S. National Arboreturm Property § 500.12 Weapons and... weapons, or explosives, either openly or concealed, except for authorized official purposes. (b) No person...

  8. Human Hepatic Cytochrome P450-Specific Metabolism of the Organophosphorus Pesticides Methyl Parathion and Diazinon

    PubMed Central

    Tian, Yuan; Knaak, James B.; Kostyniak, Paul J.; Olson, James R.

    2012-01-01

    Organophosphorus pesticides (OPs) are a public health concern due to their worldwide use and documented human exposures. Phosphorothioate OPs are metabolized by cytochrome P450s (P450s) through either a dearylation reaction to form an inactive metabolite, or through a desulfuration reaction to form an active oxon metabolite, which is a potent cholinesterase inhibitor. This study investigated the rate of desulfuration (activation) and dearylation (detoxification) of methyl parathion and diazinon in human liver microsomes. In addition, recombinant human P450s were used to determine the P450-specific kinetic parameters (Km and Vmax) for each compound for future use in refining human physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) models of OP exposure. The primary enzymes involved in bioactivation of methyl parathion were CYP2B6 (Km = 1.25 μM; Vmax = 9.78 nmol · min−1 · nmol P450−1), CYP2C19 (Km = 1.03 μM; Vmax = 4.67 nmol · min−1 · nmol P450−1), and CYP1A2 (Km = 1.96 μM; Vmax = 5.14 nmol · min−1 · nmol P450−1), and the bioactivation of diazinon was mediated primarily by CYP1A1 (Km = 3.05 μM; Vmax = 2.35 nmol · min−1 · nmol P450−1), CYP2C19 (Km = 7.74 μM; Vmax = 4.14 nmol · min−1 · nmol P450−1), and CYP2B6 (Km = 14.83 μM; Vmax = 5.44 nmol · min−1 · nmol P450−1). P450-mediated detoxification of methyl parathion only occurred to a limited extent with CYP1A2 (Km = 16.8 μM; Vmax = 1.38 nmol · min−1 · nmol P450−1) and 3A4 (Km = 104 μM; Vmax = 5.15 nmol · min−1 · nmol P450−1), whereas the major enzyme involved in diazinon detoxification was CYP2C19 (Km = 5.04 μM; Vmax = 5.58 nmol · min−1 · nmol P450−1). The OP- and P450-specific kinetic values will be helpful for future use in refining human PBPK/PD models of OP exposure. PMID:21969518

  9. 13 CFR 500.2 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Definitions. 500.2 Section 500.2 Business Credit and Assistance EMERGENCY OIL AND GAS GUARANTEED LOAN BOARD EMERGENCY OIL AND GAS GUARANTEED... small business concern under section 3 of the Small Business Act, 15 U.S.C. 632, (or a company based in...

  10. 13 CFR 500.2 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Definitions. 500.2 Section 500.2 Business Credit and Assistance EMERGENCY OIL AND GAS GUARANTEED LOAN BOARD EMERGENCY OIL AND GAS GUARANTEED... small business concern under section 3 of the Small Business Act, 15 U.S.C. 632, (or a company based in...

  11. Effects of rotation of fissioning nuclei in the angular distributions of prompt neutrons and gamma rays originating from the polarized-neutron-induced fission of 233U and 235U nuclei

    NASA Astrophysics Data System (ADS)

    Danilyan, G. V.; Klenke, J.; Kopach, Yu. N.; Krakhotin, V. A.; Novitsky, V. V.; Pavlov, V. S.; Shatalov, P. B.

    2014-06-01

    The results of an experiment devoted to searches for effects of rotation of fissioning nuclei in the angular distributions of prompt neutrons and gamma rays originating from the polarized-neutron-induced fission of 233U nuclei are presented. The effects discovered in these angular distributions are opposite in sign to their counterparts in the polarized-neutron-induced fission of 235U nuclei. This is at odds with data on the relative signs of respective effects in the angular distribution of alpha particles from the ternary fission of the same nuclei and may be indicative of problems in the model currently used to describe the effect in question. The report on which this article is based was presented at the seminar held at the Institute of Theoretical and Experimental Physics and dedicated to the 90th anniversary of the birth of Yu.G. Abov, corresponding member of Russian Academy of Sciences, Editor in Chief of the journal Physics of Atomic Nuclei.

  12. Energy dependence of fission product yields from 235U, 238U, and 239Pu with monoenergetic neutrons between thermal and 14.8 MeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gooden, Matthew; Arnold, Charles; Bhike, Megha

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurementmore » of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of two months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. Preliminary results from thermal irradiations at the MIT research reactor will also be presented and compared to present data and evaluations.« less

  13. Energy dependence of fission product yields from 235U, 238U, and 239Pu with monoenergetic neutrons between thermal and 14.8 MeV

    DOE PAGES

    Gooden, Matthew; Arnold, Charles; Bhike, Megha; ...

    2017-09-13

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurementmore » of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of two months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. Preliminary results from thermal irradiations at the MIT research reactor will also be presented and compared to present data and evaluations.« less

  14. Selective advantages of two major clones of carbapenem-resistant Pseudomonas aeruginosa isolates (CC235 and CC641) from Korea: antimicrobial resistance, virulence and biofilm-forming activity.

    PubMed

    Lee, Ji-Young; Peck, Kyong Ran; Ko, Kwan Soo

    2013-07-01

    The characteristics of carbapenem-resistant P. aeruginosa (CRPA) isolates from Korea were investigated. Two major clones, clonal complex (CC) 235 and CC641, were identified. CC235, an important international clone, might have been imported recently in Korea as this clone displayed a homogeneous genotype, oprD mutation and antimicrobial resistance profile. While 13 ST235 isolates harboured the blaIMP-6 gene, which conferred high-level meropenem resistance, CC641 isolates showed high biofilm-forming activity. CC235 and CC641 isolates showed distinct distribution of ferripyoverdine receptor type and virulence markers. While all CC235 isolates were of the fpvAIIb type and exoS(-)/exoU(+), CC641 isolates were exoS(+)/exoU(-), and all but one showed the fpvAIII type. CC235 and CC641 isolates were also characterized by different extracellular protease activity: staphylolysin and elastase activities in CC235 and CC641, respectively. Two major CRPA clones in Korea seem to be predominant, reflecting their selective advantage by virtue of antimicrobial resistance, virulence and biofilm-forming activity.

  15. A 24-week, prospective, randomized, open-label, treat-to-target pilot study of obese type 2 diabetes patients with severe insulin resistance to assess the addition of exenatide on the efficacy of u-500 regular insulin plus metformin.

    PubMed

    Distiller, Larry A; Nortje, Hendrik; Wellmann, Holger; Amod, Aslam; Lombard, Landman

    2014-11-01

    To compare the efficacy of 500 U/mL (U-500) regular insulin + metformin with U-500 regular insulin + metformin + exenatide in improving glycemic control in patients with severely insulin-resistant type 2 diabetes mellitus (T2DM). Thirty patients with T2DM and severe insulin resistance were screened, and 28 were randomized to regular insulin U-500 + metformin or the GLP-1 analog exenatide, U-500, and metformin. Glycated hemoglobin (HbA1c) levels, body weight, and insulin doses were documented at baseline and at 3 and 6 months. The number and severity hypoglycemic episodes were noted. There were 7 males and 7 females in each group (U-500 + metformin and U-500 + metformin + exenatide). Overall, U-500 insulin + metformin, either alone or with the addition of exenatide, resulted in a significant improvement in HbA1c in both groups, with no significant difference between the 2 groups. There was no meaningful weight change in those utilizing exenatide. Those on U-500 insulin and metformin alone had a tendency toward some weight gain. No severe hypoglycemia occurred during the study period. Symptomatic hypoglycemia was more common in the group on exenatide, but this occurred in only 5 patients, and the clinical significance of this is uncertain. Insulin dosage changes on U-500 regular insulin were variable but tended to be lower in those subjects on exenatide. U-500 regular insulin + metformin is effective for the treatment of T2DM patients with severe insulin resistance. The addition of exenatide may ameliorate potential weight gain but provides no additional improvement in glycemia.

  16. 14 CFR 121.235 - Fuel valves.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Fuel valves. 121.235 Section 121.235 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.235 Fuel valves. Each fuel...

  17. 14 CFR 121.235 - Fuel valves.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Fuel valves. 121.235 Section 121.235 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.235 Fuel valves. Each fuel...

  18. 14 CFR 121.235 - Fuel valves.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Fuel valves. 121.235 Section 121.235 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.235 Fuel valves. Each fuel...

  19. 14 CFR 121.235 - Fuel valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel valves. 121.235 Section 121.235 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.235 Fuel valves. Each fuel...

  20. 14 CFR 121.235 - Fuel valves.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Fuel valves. 121.235 Section 121.235 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.235 Fuel valves. Each fuel...

  1. 50 CFR 600.235 - Financial disclosure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Financial disclosure. 600.235 Section 600.235 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MAGNUSON-STEVENS ACT PROVISIONS Council Membership § 600.235 Financial...

  2. 7 CFR 764.235 - Security requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Security requirements. 764.235 Section 764.235 Agriculture Regulations of the Department of Agriculture (Continued) FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE SPECIAL PROGRAMS DIRECT LOAN MAKING Conservation Loan Program § 764.235 Security requirements. (a...

  3. 46 CFR 169.235 - Permission required.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Permission required. 169.235 Section 169.235 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification Repairs and Alterations § 169.235 Permission required. (a) Repairs or...

  4. 46 CFR 169.235 - Permission required.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Permission required. 169.235 Section 169.235 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification Repairs and Alterations § 169.235 Permission required. (a) Repairs or...

  5. DOSIMETRIC response of a REM-500 in low energy neutron fields typical of nuclear power plants.

    PubMed

    Aslam; Matysiak, W; Atanackovic, J; Waker, A J

    2012-06-01

    This study investigates the response of a REM-500 to assess neutron quality factor and dose equivalent in low energy neutron fields, which are commonly encountered in the workplace environment of nuclear power stations. The McMaster University 3 MV Van de Graaff accelerator facility was used to measure the response of the instrument in monoenergetic neutron fields in the energy range 51 to 727 keV by bombarding a thin LiF target with 1.93-2.50 MeV protons. The energy distribution of the neutron fields produced in the facility was measured by a (3)He filled gas ionization chamber. The MCA mode of the REM-500 instrument was used to collect lineal energy distributions at varying neutron energies and to calculate the frequency and dose-mean lineal energies. The effective quality factor, Q-, was also calculated using the values of Q(y)listed in the REM-500 operation manual and compared with those of ICRP 60. The authors observed a continuously increasing trend in y - F, y-D, and Q-with an increase in neutron energy. It is interesting to note that standard tissue equivalent proportional counters (TEPCs) filled with tissue equivalent(TE) gas give rise to a similar trend for these microdosimetric quantities of interest in the same energy range; however, the averages calculated in this study are larger by about 15%compared to a TEPC filled with propane-based TE gas probably because of the larger stopping power of protons in propane compared to TE gas. These somewhat larger event sizes did not result in any significant increase in the Q-compared to those obtained from a TEPC filled with TE gas and were found to be in good agreement with other measurements reported earlier at corresponding neutron energies. The instrument quality factor response, R(Q), defined as the ratio of measured quality factor to the calculated quality factor in an ICRU tissue sphere,was found to vary with neutron energy. The instrument response,R(Q), was ~0.6 at 727 keV, which deteriorates further to

  6. 7 CFR 922.235 - Assessment rate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Assessment rate. 922.235 Section 922.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... IN WASHINGTON Reserved § 922.235 Assessment rate. On and after April 1, 2010, an assessment rate of...

  7. 31 CFR 235.5 - Reclamation amounts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Reclamation amounts. 235.5 Section 235.5 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE... ON DESIGNATED DEPOSITARIES § 235.5 Reclamation amounts. Amounts received by way of reclamation on...

  8. High resolution isotopic analysis of U-bearing particles via fusion of SIMS and EDS images

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tarolli, Jay G.; Naes, Benjamin E.; Garcia, Benjamin J.

    Image fusion of secondary ion mass spectrometry (SIMS) images and X-ray elemental maps from energy-dispersive spectroscopy (EDS) was performed to facilitate the isolation and re-analysis of isotopically unique U-bearing particles where the highest precision SIMS measurements are required. Image registration, image fusion and particle micromanipulation were performed on a subset of SIMS images obtained from a large area pre-screen of a particle distribution from a sample containing several certified reference materials (CRM) U129A, U015, U150, U500 and U850, as well as a standard reference material (SRM) 8704 (Buffalo River Sediment) to simulate particles collected on swipes during routine inspections ofmore » declared uranium enrichment facilities by the International Atomic Energy Agency (IAEA). In total, fourteen particles, ranging in size from 5 – 15 µm, were isolated and re-analyzed by SIMS in multi-collector mode identifying nine particles of CRM U129A, one of U150, one of U500 and three of U850. These identifications were made within a few percent errors from the National Institute of Standards and Technology (NIST) certified atom percent values for 234U, 235U and 238U for the corresponding CRMs. This work represents the first use of image fusion to enhance the accuracy and precision of isotope ratio measurements for isotopically unique U-bearing particles for nuclear safeguards applications. Implementation of image fusion is essential for the identification of particles of interests that fall below the spatial resolution of the SIMS images.« less

  9. Neutron fluence and energy reconstruction with the IRSN recoil detector μ-TPC at 27 keV, 144 keV and 565 keV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maire, D.; Lebreton, L.; Richer, J.P.

    2015-07-01

    The French Institute for Radioprotection and Nuclear Safety (IRSN), associated to the French Metrology Institute (LNE), is developing a time projection chamber using a Micromegas anode: μ-TPC. This work is carried out in collaboration with the Laboratory of Subatomic Physics and Cosmology (LPSC). The aim is to characterize with a primary procedure the energy distribution of neutron fluence in the energy range 8 keV - 1 MeV. The time projection chambers are gaseous detectors, which are able to measure charged particles energy and to reconstruct their track if a pixelated anode is used. In our case, the gas is usedmore » as a (n, p) converter in order to detect neutrons down to few keV. Coming from elastic collisions with neutrons, recoil protons lose a part of their kinetic energy by ionizing the gas. The ionization electrons are drifted toward a pixelated anode (2D projection), read at 50 MHz by a self-triggered electronic system to obtain the third track dimension. The neutron energy is reconstructed event by event thanks to proton scattering angle and proton energy measurements. The scattering angle is deduced from the 3D track. The proton energy is obtained by charge collection measurements, knowing the ionization quenching factor (i.e. the part of proton kinetic energy lost by ionizing the gas). The fluence is calculated thanks to the detected events number and the simulated detector response. The μ-TPC is a new reliable detector which enables to measure energy distribution of the neutron fluence without deconvolution or neutron calibration contrary to usual gaseous counters. The μ-TPC is still being developed and measurements have been carried out at the AMANDE facility, with neutrons energies going from 8 keV to 565 keV. After the context and the μ-TPC working principle presentation, measurements of the neutron energy and fluence at 27.2 keV, 144 keV and 565 keV are shown and compared to the complete detector simulation. This work shows the first direct

  10. 46 CFR 148.235 - Castor beans.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Castor beans. 148.235 Section 148.235 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.235 Castor beans. (a) This part applies only to the stowage and transportation of whole castor beans. Castor meal, castor...

  11. 46 CFR 148.235 - Castor beans.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Castor beans. 148.235 Section 148.235 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.235 Castor beans. (a) This part applies only to the stowage and transportation of whole castor beans. Castor meal, castor...

  12. 46 CFR 148.235 - Castor beans.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Castor beans. 148.235 Section 148.235 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.235 Castor beans. (a) This part applies only to the stowage and transportation of whole castor beans. Castor meal, castor...

  13. 46 CFR 148.235 - Castor beans.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Castor beans. 148.235 Section 148.235 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.235 Castor beans. (a) This part applies only to the stowage and transportation of whole castor beans. Castor meal, castor...

  14. 7 CFR 915.235 - Assessment rate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Assessment rate. 915.235 Section 915.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Assessment Rates § 915.235 Assessment rate. On and after April 1, 2010, an assessment rate of $0.37 per 55...

  15. 7 CFR 915.235 - Assessment rate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Assessment rate. 915.235 Section 915.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Assessment Rates § 915.235 Assessment rate. On and after April 1, 2012, an assessment rate of $0.25 per 55...

  16. 7 CFR 915.235 - Assessment rate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Assessment rate. 915.235 Section 915.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Assessment Rates § 915.235 Assessment rate. On and after April 1, 2005, an assessment rate of $0.27 per 55...

  17. 7 CFR 915.235 - Assessment rate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Assessment rate. 915.235 Section 915.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Assessment Rates § 915.235 Assessment rate. On and after April 1, 2010, an assessment rate of $0.37 per 55...

  18. 7 CFR 915.235 - Assessment rate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Assessment rate. 915.235 Section 915.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Assessment Rates § 915.235 Assessment rate. On and after April 1, 2012, an assessment rate of $0.25 per 55...

  19. 7 CFR 764.235 - Security requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Security requirements. 764.235 Section 764.235... AGRICULTURE SPECIAL PROGRAMS DIRECT LOAN MAKING Conservation Loan Program § 764.235 Security requirements. (a... estate may be taken as additional security if needed. (c) Loans of $25,000 of less for real estate...

  20. Pressure-composition relations for coexisting gases and liquids and the critical points in the system NaCl-H2O at 450, 475, and 500°C

    USGS Publications Warehouse

    Rosenbauer, Robert J.; Bischoff, James L.

    1987-01-01

    Pressure-temperature-composition (P, T, x) relations for the co-existing vapor and liquid phases in the system NaCl-H2O were determined experimentally at 450, 475, and 500°C. Data for each isotherm includeP-x relations near the critical point and extend to the three-phase assemblage vapor-liquid-halite on the vapor side. On the liquid side the P-x data range from the critical point to the room-temperature halite saturation point (~25 wt.% NaCl). Critical pressures were calculated from measured pressures and compositions and classical theory. The results generally support the few data points of Urusova (1974, 1975) and Ölander and Liander (1950) but differ markedly from the extensive data of Sourirajan andKennedy (1962).

  1. Energy spectrum of sputtered uranium

    NASA Technical Reports Server (NTRS)

    Weller, R. A.; Tombrello, T. A.

    1977-01-01

    The fission track technique for detecting uranium 235 was used in conjunction with a mechanical time-of-flight spectrometer to measure the energy spectrum in the region 1 eV to 1 keV of material sputtered from a 93% enriched U-235 foil by 80 keV Ar-40(+) ions. The spectrum was found to exhibit a peak in the region 2-4 eV and to decrease approximately as E to the -1.77 power for E is approximately greater than 100 eV. The design, construction and resolution of the mechanical spectrometer are discussed and comparisons are made between the data and the predictions of the ramdom collision cascade model of sputtering.

  2. 7 CFR 922.235 - Assessment rate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Assessment rate. 922.235 Section 922.235 Agriculture... IN WASHINGTON Assessment Rate § 922.235 Assessment rate. On or after April 1, 2012, an assessment rate of $0.50 per ton is established for the Washington Apricot Marketing Committee. [77 FR 72683, Dec...

  3. 7 CFR 922.235 - Assessment rate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Assessment rate. 922.235 Section 922.235 Agriculture... IN WASHINGTON Assessment Rate § 922.235 Assessment rate. On and after April 1, 2010, an assessment rate of $1.50 per ton is established for the Washington Apricot Marketing Committee. [75 FR 51926, Aug...

  4. 7 CFR 922.235 - Assessment rate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Assessment rate. 922.235 Section 922.235 Agriculture... IN WASHINGTON Assessment Rate § 922.235 Assessment rate. On and after April 1, 2013, an assessment rate of $1.50 per ton is established for Washington apricots handled in the production area. [78 FR...

  5. 7 CFR 922.235 - Assessment rate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Assessment rate. 922.235 Section 922.235 Agriculture... IN WASHINGTON Assessment Rate § 922.235 Assessment rate. On or after April 1, 2009, an assessment rate of $1.00 per ton is established for the Washington Apricot Marketing Committee. [74 FR 37499, July...

  6. Prediction of Cytochrome P450 Profiles of Environmental Chemicals with QSAR Models Built from Drug-like Molecules

    EPA Science Inventory

    The human cytochrome P450 (CYP450) enzyme family is involved in the biotransformation of many environmental chemicals. As part of the U.S. Tox21 effort, we profiled the CYP450 activity of ~2800 chemicals predominantly of environmental concern against CYP1A2, CYP2C19, CYP2C9, CYP2...

  7. 7 CFR 906.235 - Assessment rate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Assessment rate. 906.235 Section 906.235 Agriculture... RIO GRANDE VALLEY IN TEXAS Rules and Regulations § 906.235 Assessment rate. On and after August 1, 2012, an assessment rate of $0.16 per 7/10-bushel carton or equivalent is established for oranges and...

  8. 7 CFR 906.235 - Assessment rate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Assessment rate. 906.235 Section 906.235 Agriculture... RIO GRANDE VALLEY IN TEXAS Rules and Regulations § 906.235 Assessment rate. On and after August 1, 2011, an assessment rate of $0.14 per 7/10-bushel carton or equivalent is established for oranges and...

  9. 7 CFR 906.235 - Assessment rate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Assessment rate. 906.235 Section 906.235 Agriculture... RIO GRANDE VALLEY IN TEXAS Rules and Regulations § 906.235 Assessment rate. On and after August 1, 2004, an assessment rate of $0.12 per 7/10-bushel carton or equivalent is established for oranges and...

  10. 7 CFR 906.235 - Assessment rate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Assessment rate. 906.235 Section 906.235 Agriculture... RIO GRANDE VALLEY IN TEXAS Rules and Regulations § 906.235 Assessment rate. On and after August 1, 2011, an assessment rate of $0.14 per 7/10-bushel carton or equivalent is established for oranges and...

  11. 7 CFR 905.235 - Assessment rate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Assessment rate. 905.235 Section 905.235 Agriculture... TANGELOS GROWN IN FLORIDA Assessment Rates § 905.235 Assessment rate. On and after August 1, 2007, an assessment rate of $0.0072 per 4/5 bushel carton or equivalent is established for Florida citrus covered...

  12. 7 CFR 905.235 - Assessment rate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Assessment rate. 905.235 Section 905.235 Agriculture... TANGELOS GROWN IN FLORIDA Assessment Rates § 905.235 Assessment rate. On and after August 1, 2007, an assessment rate of $0.0072 per 4/5 bushel carton or equivalent is established for Florida citrus covered...

  13. 7 CFR 905.235 - Assessment rate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Assessment rate. 905.235 Section 905.235 Agriculture... TANGELOS GROWN IN FLORIDA Assessment Rates § 905.235 Assessment rate. On and after August 1, 2007, an assessment rate of $0.0072 per 4/5 bushel carton or equivalent is established for Florida citrus covered...

  14. 7 CFR 905.235 - Assessment rate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Assessment rate. 905.235 Section 905.235 Agriculture... TANGELOS GROWN IN FLORIDA Assessment Rates § 905.235 Assessment rate. On and after August 1, 2007, an assessment rate of $0.0072 per 4/5 bushel carton or equivalent is established for Florida citrus covered...

  15. 7 CFR 905.235 - Assessment rate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Assessment rate. 905.235 Section 905.235 Agriculture... TANGELOS GROWN IN FLORIDA Assessment Rates § 905.235 Assessment rate. On and after August 1, 2012, an assessment rate of $0.008 per 4/5 bushel carton or equivalent is established for Florida citrus covered under...

  16. 7 CFR 906.235 - Assessment rate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Assessment rate. 906.235 Section 906.235 Agriculture... RIO GRANDE VALLEY IN TEXAS Rules and Regulations § 906.235 Assessment rate. On and after August 1, 2004, an assessment rate of $0.12 per 7/10-bushel carton or equivalent is established for oranges and...

  17. 21 CFR 314.235 - Judicial review.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 5 2012-04-01 2012-04-01 false Judicial review. 314.235 Section 314.235 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE APPLICATIONS FOR FDA APPROVAL TO MARKET A NEW DRUG Hearing Procedures for New Drugs § 314.235...

  18. 21-Aminosteroids prevent the down-regulation of hepatic cytochrome P450 induced by hypoxia and inflammation in conscious rabbits

    PubMed Central

    Galal, Ahmed; du Souich, Patrick

    1999-01-01

    This study was conducted to assess whether a 21-aminosteroid, U74389G, could prevent the down-regulation of hepatic cytochrome P450 (P450) induced by acute moderate hypoxia or an inflammatory reaction.The rabbits of two groups (n=6 per group) were subjected to acute moderate hypoxia (PaO2≈35 mmHg), one pre-treated with U74389G (3 mg kg−1 i.v. every 6 h, for 48 h). The rabbits of two other groups received 5 ml of turpentine s.c., one of them being pre-treated with U74389G (3 mg kg−1 i.v. every 6 h, for 72 h). The kinetics of theophylline (2.5 mg kg−1) were assessed to evaluate the activity of the P450. Once the rabbits were sacrificed, the P450 content and the amount of thiobarbituric acid reactive substances (TBARS), a marker of lipid peroxidation, were estimated in the liver.Compared with control rabbits, hypoxia and inflammation increased theophylline plasma concentrations, as a result of a decrease in theophylline systemic clearance (P<0.05). Both experimental conditions reduced hepatic content of P450 by 40–50% (P<0.05) and increased the amount of hepatic TBARS by around 50% (P<0.05). Pre-treatment with U74389G prevented the hypoxia- and inflammation-induced decrease in theophylline systemic clearance, the down-regulation of hepatic P450, and the increase in liver TBARS.It is concluded that in the rabbit, U74389G prevents hepatic P450 depression produced by acute moderate hypoxia and a turpentine-induced inflammatory reaction, possibly by eliciting a radical quenching antioxidant activity. PMID:10510447

  19. 49 CFR 235.9 - Civil penalty.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Civil penalty. 235.9 Section 235.9 Transportation... SIGNAL SYSTEM OR RELIEF FROM THE REQUIREMENTS OF PART 236 § 235.9 Civil penalty. Any person (an entity of... violates any requirement of this part or causes the violation of any such requirement is subject to a civil...

  20. 49 CFR 235.9 - Civil penalty.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Civil penalty. 235.9 Section 235.9 Transportation... SIGNAL SYSTEM OR RELIEF FROM THE REQUIREMENTS OF PART 236 § 235.9 Civil penalty. Any person (an entity of... violates any requirement of this part or causes the violation of any such requirement is subject to a civil...

  1. 49 CFR 235.9 - Civil penalty.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Civil penalty. 235.9 Section 235.9 Transportation... SIGNAL SYSTEM OR RELIEF FROM THE REQUIREMENTS OF PART 236 § 235.9 Civil penalty. Any person (an entity of... violates any requirement of this part or causes the violation of any such requirement is subject to a civil...

  2. 49 CFR 235.9 - Civil penalty.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Civil penalty. 235.9 Section 235.9 Transportation... SIGNAL SYSTEM OR RELIEF FROM THE REQUIREMENTS OF PART 236 § 235.9 Civil penalty. Any person (an entity of... violates any requirement of this part or causes the violation of any such requirement is subject to a civil...

  3. 49 CFR 235.9 - Civil penalty.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Civil penalty. 235.9 Section 235.9 Transportation... SIGNAL SYSTEM OR RELIEF FROM THE REQUIREMENTS OF PART 236 § 235.9 Civil penalty. Any person (an entity of... violates any requirement of this part or causes the violation of any such requirement is subject to a civil...

  4. Evaluation of the ²³⁹Pu prompt fission neutron spectrum induced by neutrons of 500 keV and associated covariances

    DOE PAGES

    Neudecker, D.; Talou, P.; Kawano, T.; ...

    2015-08-01

    We present evaluations of the prompt fission neutron spectrum (PFNS) of ²³⁹Pu induced by 500 keV neutrons, and associated covariances. In a previous evaluation by Talou et al. 2010, surprisingly low evaluated uncertainties were obtained, partly due to simplifying assumptions in the quantification of uncertainties from experiment and model. Therefore, special emphasis is placed here on a thorough uncertainty quantification of experimental data and of the Los Alamos model predicted values entering the evaluation. In addition, the Los Alamos model was extended and an evaluation technique was employed that takes into account the qualitative differences between normalized model predicted valuesmore » and experimental shape data. These improvements lead to changes in the evaluated PFNS and overall larger evaluated uncertainties than in the previous work. However, these evaluated uncertainties are still smaller than those obtained in a statistical analysis using experimental information only, due to strong model correlations. Hence, suggestions to estimate model defect uncertainties are presented, which lead to more reasonable evaluated uncertainties. The calculated k eff of selected criticality benchmarks obtained with these new evaluations agree with each other within their uncertainties despite the different approaches to estimate model defect uncertainties. The k eff one standard deviations overlap with some of those obtained using ENDF/B-VII.1, albeit their mean values are further away from unity. Spectral indexes for the Jezebel critical assembly calculated with the newly evaluated PFNS agree with the experimental data for selected (n,γ) and (n,f) reactions, and show improvements for high-energy threshold (n,2n) reactions compared to ENDF/B-VII.1.« less

  5. 33 CFR 334.235 - Potomac River, Marine Corps Base Quantico (MCB Quantico) in vicinity of Marine Corps Air Facility...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Potomac River, Marine Corps Base... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.235 Potomac River, Marine Corps Base Quantico... the navigable waters of the Potomac River extending approximately 500 meters from the high-water mark...

  6. 33 CFR 334.235 - Potomac River, Marine Corps Base Quantico (MCB Quantico) in vicinity of Marine Corps Air Facility...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Potomac River, Marine Corps Base... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.235 Potomac River, Marine Corps Base Quantico... the navigable waters of the Potomac River extending approximately 500 meters from the high-water mark...

  7. 33 CFR 334.235 - Potomac River, Marine Corps Base Quantico (MCB Quantico) in vicinity of Marine Corps Air Facility...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Potomac River, Marine Corps Base... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.235 Potomac River, Marine Corps Base Quantico... the navigable waters of the Potomac River extending approximately 500 meters from the high-water mark...

  8. 33 CFR 334.235 - Potomac River, Marine Corps Base Quantico (MCB Quantico) in vicinity of Marine Corps Air Facility...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Potomac River, Marine Corps Base... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.235 Potomac River, Marine Corps Base Quantico... the navigable waters of the Potomac River extending approximately 500 meters from the high-water mark...

  9. Fracture toughness and fracture behavior of CLAM steel in the temperature range of 450 °C-550 °C

    NASA Astrophysics Data System (ADS)

    Zhao, Yanyun; Liang, Mengtian; Zhang, Zhenyu; Jiang, Man; Liu, Shaojun

    2018-04-01

    In order to analyze the fracture toughness and fracture behavior (J-R curves) of China Low Activation Martensitic (CLAM) steel under the design service temperature of Test Blanket Module of the International Thermonuclear Experimental Reactor, the quasi-static fracture experiment of CLAM steel was carried out under the temperature range of 450 °C-550 °C. The results indicated that the fracture behavior of CLAM steel was greatly influenced by test temperature. The fracture toughness increased slightly as the temperature increased from 450 °C to 500 °C. In the meanwhile, the fracture toughness at 550 °C could not be obtained due to the plastic deformation near the crack tip zone. The microstructure analysis based on the fracture topography and the interaction between dislocations and lath boundaries showed two different sub-crack propagation modes: growth along 45° of the main crack direction at 450 °C and growth perpendicular to the main crack at 500 °C.

  10. Energy dependence of fission product yields from 235U, 238U, and 239Pu with monoenergetic neutrons between thermal and 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, Matthew; Arnold, Charles; Bhike, Megha; Bredeweg, Todd; Fowler, Malcolm; Krishichayan; Tonchev, Anton; Tornow, Werner; Stoyer, Mark; Vieira, David; Wilhelmy, Jerry

    2017-09-01

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of two months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. Preliminary results from thermal irradiations at the MIT research reactor will also be presented and compared to present data and evaluations. This work was performed under the auspices of the U.S. Department of Energy by Los Alamos National Security, LLC under contract DE-AC52-06NA25396, Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344 and by Duke University and Triangle Universities Nuclear Laboratory through NNSA Stewardship Science Academic Alliance grant No. DE-FG52-09NA29465, DE-FG52-09NA29448 and Office of Nuclear Physics Grant No. DE-FG02-97ER41033.

  11. 7 CFR 65.235 - Raised.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Raised. 65.235 Section 65.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL...

  12. Development of High-Field ST Merging Experiment: TS-U for High Power Reconnection Heating

    NASA Astrophysics Data System (ADS)

    Ono, Y.; Koike, H.; Tanabe, H.; Himeno, S.; Ishida, S.; Kimura, K.; Kawanami, M.; Narita, M.; Takahata, Y.; Yokoyama, T.; Inomoto, M.; Cheng, C. Z.

    2016-10-01

    We are developing high-magnetic field ST merging/ reconnection experiment TS-U with Brec = 0.3-0.5T, based on our scaling law of reconnection heating energy proportional to square of the reconnecting (poloidal) magnetic field Brec. This scaling law indicates that the high-Brec ST merging will heat ions to the burning plasma regime without using any additional heating facility. Its mechanism is that the reconnection outflow accelerates mainly ions up to the poloidal Alfven speed like the Sweet-Parker model. The shock-like density pileups thermalize the accelerated ions in the down-streams in agreement with recent solar satellite observations and PIC simulation results. We already documented significant ion heating of spheromak and ST mergings up to 0.25keV in TS-3 and 1.2keV in MAST, leading us to the high-Brec merging experiment TS-U. It is noted that high-resolution (>500 channel) 2D measurements of ion and electron temperatures is being developed for the purpose of solving all acceleration and heating effects of magnetic reconnection, such as the huge outflow heating of ions in the downstream and electron heating localized at the X-point.

  13. 33 CFR 105.235 - Communications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Communications. 105.235 Section... MARITIME SECURITY: FACILITIES Facility Security Requirements § 105.235 Communications. (a) The Facility... conditions at the facility. (b) Communication systems and procedures must allow effective and continuous...

  14. 33 CFR 105.235 - Communications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Communications. 105.235 Section... MARITIME SECURITY: FACILITIES Facility Security Requirements § 105.235 Communications. (a) The Facility... conditions at the facility. (b) Communication systems and procedures must allow effective and continuous...

  15. 33 CFR 105.235 - Communications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Communications. 105.235 Section... MARITIME SECURITY: FACILITIES Facility Security Requirements § 105.235 Communications. (a) The Facility... conditions at the facility. (b) Communication systems and procedures must allow effective and continuous...

  16. 33 CFR 105.235 - Communications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Communications. 105.235 Section... MARITIME SECURITY: FACILITIES Facility Security Requirements § 105.235 Communications. (a) The Facility... conditions at the facility. (b) Communication systems and procedures must allow effective and continuous...

  17. 23 CFR 450.334 - Self-certifications and Federal certifications.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 324 of title 23 U.S.C. regarding the prohibition of discrimination based on gender; and (10) Section... RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.334... certify at least every four years that the metropolitan transportation planning process is being carried...

  18. 23 CFR 450.334 - Self-certifications and Federal certifications.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 324 of title 23 U.S.C. regarding the prohibition of discrimination based on gender; and (10) Section... RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.334... certify at least every four years that the metropolitan transportation planning process is being carried...

  19. 48 CFR 235.072 - Additional contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 252.235-7011, Final Scientific or Technical Report, in solicitations and contracts for research and... SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235... involving research on live vertebrate animals. (b) Use the clause at 252.235-7003, Frequency Authorization...

  20. 49 CFR 190.235 - Civil actions generally.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Civil actions generally. 190.235 Section 190.235... PROCEDURES Enforcement Specific Relief § 190.235 Civil actions generally. Whenever it appears to the... or appropriate, including mandatory or prohibitive injunctive relief, interim equitable relief, civil...

  1. 48 CFR 235.072 - Additional contract clauses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 252.235-7011, Final Scientific or Technical Report, in solicitations and contracts for research and... SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235... involving research on live vertebrate animals. (b) Use the clause at 252.235-7003, Frequency Authorization...

  2. Nuclear Data Sheets for A = 235

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Browne, E.; Tuli, J. K.

    Spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented here for all nuclei with mass number A=235. The highlight of this evaluation consists of the precise and comprehensive Coulomb excitation study (2012Wa35) on ²³⁵U, which in addition to the 7/2[743] ground state rotational band, extended the 1/2[631], 5/2[622], 5/2[752], and 3/2[631] rotational bands up to Jπ=53/2+, 49/2+, 441/2–, and 43/2+, respectively. This evaluation presents a study (2010Hu02) of the ²³⁷Np(¹¹⁶Sn, ¹¹⁸Snγ) reaction where the ground state rotational band 5/2[642] was observed up to Jπ=(53/2+). It is worth for historical knowledge to mention the report onmore » the “Discovery of isotopes of the transuranium elements with 93≤Z≤98” (2013Fr02), where the information for elements Np, Pu, and Am with mass number A=235 is given. ²³⁵Cf has not been observed. The alpha hindrance factors (HF) presented in this evaluation were calculated using values of the radius parameter (r₀) interpolated from those for even–even adjacent nuclei given by 1998Ak04.« less

  3. Nuclear Data Sheets for A = 235

    DOE PAGES

    Browne, E.; Tuli, J. K.

    2014-11-01

    Spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented here for all nuclei with mass number A=235. The highlight of this evaluation consists of the precise and comprehensive Coulomb excitation study (2012Wa35) on ²³⁵U, which in addition to the 7/2[743] ground state rotational band, extended the 1/2[631], 5/2[622], 5/2[752], and 3/2[631] rotational bands up to Jπ=53/2+, 49/2+, 441/2–, and 43/2+, respectively. This evaluation presents a study (2010Hu02) of the ²³⁷Np(¹¹⁶Sn, ¹¹⁸Snγ) reaction where the ground state rotational band 5/2[642] was observed up to Jπ=(53/2+). It is worth for historical knowledge to mention the report onmore » the “Discovery of isotopes of the transuranium elements with 93≤Z≤98” (2013Fr02), where the information for elements Np, Pu, and Am with mass number A=235 is given. ²³⁵Cf has not been observed. The alpha hindrance factors (HF) presented in this evaluation were calculated using values of the radius parameter (r₀) interpolated from those for even–even adjacent nuclei given by 1998Ak04.« less

  4. Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, M.; Arnold, C.; Bredeweg, T.; Vieira, D.; Wilhelmy, J.; Tonchev, A.; Stoyer, M.; Bhike, M.; Krishichayan, F.; Tornow, W.; Fowler, M.

    2015-10-01

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and ?-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. ?-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of 2 months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. These results are compared to previous measurements and theoretical estimates. This work was performed under the auspices of the USDoE by Los Alamos National Security, LLC under Contract DE-AC52-06NA25396.

  5. 40 CFR 35.235 - Maximum federal share.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Maximum federal share. 35.235 Section 35.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE...)(1)) § 35.235 Maximum federal share. The Regional Administrator may provide up to 100 percent of the...

  6. 48 CFR 235.072 - Additional contract clauses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Additional contract clauses. 235.072 Section 235.072 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.072 Additional contract clauses. (a) Use the...

  7. 48 CFR 235.072 - Additional contract clauses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Additional contract clauses. 235.072 Section 235.072 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.072 Additional contract clauses. (a) Use the...

  8. 42 CFR 413.235 - Patient-level adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Patient-level adjustments. 413.235 Section 413.235 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE... Disease (ESRD) Services and Organ Procurement Costs § 413.235 Patient-level adjustments. Adjustments to...

  9. Precise determination of U isotopic compositions in low concentration carbonate samples by MC-ICP-MS.

    PubMed

    Wang, Ruo-Mei; You, Chen-Feng

    2013-03-30

    We developed a fast and simple analytical procedure for precise determination of U isotopic compositions in low concentration natural samples. The main advantage of the new method is that it requires only 12ng U and can obtain all U isotopic ratios without using spike. Five carbonate reference materials (JCp-1, RKM-4, RKM-5, GBW04412 and GBW04413) and 3 international standards with different matrices (IAPSO, IRMM-3184 and CRM-U010) were analyzed for ((234)U/(238)U) and (238)U/(235)U ratios by MC-ICPMS. Using our method, the results for these standards are in close agreement with the certified values, 1.144 ± 0.004, 0.966 ± 0.004 and 0.990 ± 0.003 for ((234)U/(238)U) and 137.72 ± 0.13, 137.64 ± 0.15 and 98.63 ± 0.04 for (238)U/(235)U, in IAPSO, IRMM-3184 and CRM-U010, respectively. The long-term reproducibility of ((234)U/(238)U) and (238)U/(235)U is 0.970 ± 0.002 and 137.56 ± 0.09; 1.144 ± 0.004 and 137.72 ± 0.13, respectively, for in-house U solution and IAPSO. The new ((234)U/(238)U) results for carbonates show much better precision than previous studies and also reflect their age variability. The obtained (238)U/(235)U ratios, representing the first measurements in these carbonate specimens, are rather constant. The method described here requires only 12 ng of U for analysis and can be completed in 5.2 min. The approach provides a fast method to measure ((234)U/(238)U) and (238)U/(235)U ratios in sample matrices commonly encountered in studies of chemical weathering, oceanography and paleoclimatology. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. M sub shell X-ray emission cross section measurements for Pt, Au, Hg, Pb, Th and U at 8 and 10 keV synchrotron photons

    NASA Astrophysics Data System (ADS)

    Kaur, Gurpreet; Gupta, Sheenu; Tiwari, M. K.; Mittal, Raj

    2014-02-01

    M sub shell X-ray emission cross sections of Pt, Au, Hg, Pb, Th and U at 8 and 10 keV photon energies have been determined with linearly polarized photon beam from Indus-2 synchrotron source. The measured cross sections have been reported for the first time and were used to check the available theoretical Dirac-Hartree-Slater (DHS) and Dirac-Fock (DF) values reported in literature and also the presently derived Non Relativistic Hartree-Slater (NRHS), DF and DHS values for Mξ, Mδ, Mα, Mβ, Mγ, Mm1 and Mm2 group of X-rays.

  11. 29 CFR 780.305 - 500 man-day provision.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false 500 man-day provision. 780.305 Section 780.305 Labor...) Statutory Provisions § 780.305 500 man-day provision. (a) Section 3(u) of the Act defines man-day to mean “any day during which an employee performs agricultural labor for not less than 1 hour.” 500 man-days...

  12. 29 CFR 780.305 - 500 man-day provision.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false 500 man-day provision. 780.305 Section 780.305 Labor...) Statutory Provisions § 780.305 500 man-day provision. (a) Section 3(u) of the Act defines man-day to mean “any day during which an employee performs agricultural labor for not less than 1 hour.” 500 man-days...

  13. 29 CFR 780.305 - 500 man-day provision.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false 500 man-day provision. 780.305 Section 780.305 Labor...) Statutory Provisions § 780.305 500 man-day provision. (a) Section 3(u) of the Act defines man-day to mean “any day during which an employee performs agricultural labor for not less than 1 hour.” 500 man-days...

  14. 29 CFR 780.305 - 500 man-day provision.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false 500 man-day provision. 780.305 Section 780.305 Labor...) Statutory Provisions § 780.305 500 man-day provision. (a) Section 3(u) of the Act defines man-day to mean “any day during which an employee performs agricultural labor for not less than 1 hour.” 500 man-days...

  15. 49 CFR 192.235 - Preparation for welding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Preparation for welding. 192.235 Section 192.235... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.235 Preparation for welding. Before beginning any welding, the welding surfaces must be clean and free of any material that...

  16. 46 CFR 154.235 - Cargo tank location.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Cargo tank location. 154.235 Section 154.235 Shipping... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Ship Survival Capability and Cargo Tank Location § 154.235 Cargo tank location. (a) For type IG hulls, cargo...

  17. 46 CFR 154.235 - Cargo tank location.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Cargo tank location. 154.235 Section 154.235 Shipping... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Ship Survival Capability and Cargo Tank Location § 154.235 Cargo tank location. (a) For type IG hulls, cargo...

  18. 46 CFR 154.235 - Cargo tank location.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Cargo tank location. 154.235 Section 154.235 Shipping... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Ship Survival Capability and Cargo Tank Location § 154.235 Cargo tank location. (a) For type IG hulls, cargo...

  19. 49 CFR 192.235 - Preparation for welding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Preparation for welding. 192.235 Section 192.235... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.235 Preparation for welding. Before beginning any welding, the welding surfaces must be clean and free of any material that...

  20. 49 CFR 192.235 - Preparation for welding.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Preparation for welding. 192.235 Section 192.235... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.235 Preparation for welding. Before beginning any welding, the welding surfaces must be clean and free of any material that...

  1. 49 CFR 192.235 - Preparation for welding.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Preparation for welding. 192.235 Section 192.235... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.235 Preparation for welding. Before beginning any welding, the welding surfaces must be clean and free of any material that...

  2. 49 CFR 192.235 - Preparation for welding.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Preparation for welding. 192.235 Section 192.235... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.235 Preparation for welding. Before beginning any welding, the welding surfaces must be clean and free of any material that...

  3. 46 CFR 154.235 - Cargo tank location.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo tank location. 154.235 Section 154.235 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... Survival Capability and Cargo Tank Location § 154.235 Cargo tank location. (a) For type IG hulls, cargo...

  4. 49 CFR 372.235 - New York, NY.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false New York, NY. 372.235 Section 372.235... ZONES, AND TERMINAL AREAS Commercial Zones § 372.235 New York, NY. The zone adjacent to, and commercially a part of, New York, NY, within which transportation by motor vehicle, in interstate or foreign...

  5. 75 FR 3905 - Proposed Collection; Comment Request for an Unmodified OGE Form 450 Executive Branch Confidential...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ... OFFICE OF GOVERNMENT ETHICS Proposed Collection; Comment Request for an Unmodified OGE Form 450 Executive Branch Confidential Financial Disclosure Report AGENCY: Office of Government Ethics (OGE). ACTION... message). FAX: 202-482-9237. Mail, Hand Delivery/Courier: Office of Government Ethics, Suite 500, 1201 New...

  6. Background reduction in 236U/238U measurements

    NASA Astrophysics Data System (ADS)

    Buompane, Raffaele; De Cesare, Mario; De Cesare, Nicola; Di Leva, Antonino; D'Onofrio, Antonio; Fifield, L. Keith; Fröhlich, Michaela; Gialanella, Lucio; Marzaioli, Fabio; Sabbarese, Carlo; Terrasi, Filippo; Tims, Stephen; Wallner, Anton

    2015-10-01

    The measurements of actinide isotopic ratios, in particular 236U/238U, in environmental samples requires high sensitivity. In particular, special effort must be devoted to the suppression of interfering nuclides, such as 235,238U, when measuring 236U. At the AMS facility of CIRCE, isotopic ratios down to ∼10-10 are currently measured using a gas E - ΔE detector. In order to push this limit lower towards natural levels, a time-of-flight system is used, featuring a micro-channel plate start detector and a Si stop detector. As the mass resolution of the latter is limited by the layout, an attempt to reduce the abundant isotope interference by other means has been undertaken. In this study, we report preliminary results on the characterization of the presence of molecular interferences when using UO-, UC- and UC2- as injected molecular ions. In particular the possibility to stabilize the current yield from carbide cathodes has been investigated: it was found that the best cathode preparation procedure is obtained pressing U salts baked at 800 °C mixed with graphite and Al powder. Moreover, the 238U background in 236U measurements is strongly reduced injecting UC- ions, as verified using a time-of-flight detection system. On the other hand, 235U interference is larger with respect to UO- injection, but this increase is smaller than expected on the basis of abundances of 13C and 17O in UC and UC2 molecules on one side and UO, on the other.

  7. Physical conditions in star-forming regions around S235

    NASA Astrophysics Data System (ADS)

    Kirsanova, M. S.; Wiebe, D. S.; Sobolev, A. M.; Henkel, C.; Tsivilev, A. P.

    2014-01-01

    Gas density and temperature in star-forming regions around Sh2-235 are derived from ammonia line observations. This information is used to evaluate formation scenarios and to determine evolutionary stages of the young embedded clusters S235 East 1, S235 East 2 and S235 Central. We also estimate the gas mass in the embedded clusters and its ratio to the stellar mass. S235 East 1 appears to be less evolved than S235 East 2 and S235 Central. In S235 East 1 the molecular gas mass exceeds that in the other clusters. Also, this cluster is more embedded in the parent gas cloud than the other two. Comparison with a theoretical model shows that the formation of these three clusters could have been stimulated by the expansion of the Sh2-235 H II region (hereafter S235) via a collect-and-collapse process, provided the density in the surrounding gas exceeds 3 × 103 cm-3, or via collapse of pre-existing clumps. The expansion of S235 cannot be responsible for star formation in the southern S235 A-B region. However, formation of the massive stars in this region might have been triggered by a large-scale supernova shock. Thus, triggered star formation in the studied region may come in three varieties, namely collect-and-collapse and collapse of pre-existing clumps, both initiated by expansion of the local H II regions, and triggered by an external large-scale shock. We argue that the S235 A H II region expands into a highly non-uniform medium with increasing density. It is too young to trigger star formation in its vicinity by a collect-and-collapse process. There is an age spread inside the S235 A-B region. Massive stars in the S235 A-B region are considerably younger than lower mass stars in the same area. This follows from the estimates of their ages and the ages of associated H II regions.

  8. Measurement of the 238U neutron-capture cross section and gamma-emission spectra from 10 eV to 100 keV using the DANCE detector at LANSCE

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ullmann, John L; Couture, A J; Keksis, A L

    2010-01-01

    A careful new measurement of the {sup 238}U(n,{gamma}) cross section from 10 eV to 100 keV has been made using the DANCE detector at LANSCE. DANCE is a 4{pi} calorimetric scintillator array consisting of 160 BaF{sub 2} crystals. Measurements were made on a 48 mg/cm{sup 2} depleted uranium target. The cross sections are in general good agreement with previous measurements. The gamma-ray emission spectra, as a function of gamma multiplicity, were also measured and compared to model calculations.

  9. The 3 H(d , γ) Reaction at Ec . m . <= 300 keV

    NASA Astrophysics Data System (ADS)

    Parker, C. E.; Brune, C. R.; Massey, T. N.; O'Donnell, J. E.; Richard, A. L.; Sayre, D. B.

    2015-04-01

    The 3 H(d , γ) 5He reaction has been measured using a 500-keV pulsed deuteron beam incident on a stopping titanium tritide target at the Edwards Accelerator Laboratory. The time-of-flight technique has been used to distinguish the γ-rays from neutrons in the bismuth germinate (BGO) γ-ray detector. A stilbene scintillator and an NE-213 scintillator have been used to detect the neutrons from the 3 H(d , n) α reaction using both the pulse-shape discrimination and time-of-flight techniques. A newly designed target holder with a silicon surface barrier detector to simultaneously measure α-particles to normalize the number of neutrons, along with a new titanium tritide target, was incorporated for subsequent measurements. The γ-rays have been measured at laboratory angles of 0 °, 45 °, 90 °, and 135 °. Information about the γ-ray energy distribution for the unbound ground state and first excited state of 5He can be obtained experimentally by comparing the BGO data to Monte Carlo simulations. The 3 H(d , γ) /3 H(d , n) branching ratio has also been measured. Data analysis is currently underway for the subsequent measurements. This work is supported in part by Lawrence Livermore National Laboratory and the U.S. D.O.E. (NNSA) through Grant No. DE-NA0001837.

  10. Energy Dependence of Fission Product Yields from 235 U, 238U, and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, Matthew Edgell

    A joint collaboration between the Triangle Universities Nuclear Laboratory (TUNL), Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL) has performed a set of absolute Fission Product Yield (FPY) measurements. Using monoenergetic neutron at energies between 0.5 and 14.8 MeV, the excitation functions of a number of fission products from 235U, 238U and 239Pu have begun to be mapped out. This work has practical applications for the determination of weapon yields and the rate of burn-up in nuclear reactors, while also providing important insight into the fission process. Combining the use of a dual-fission ionization chamber and gamma-ray spectroscopy, absolute FPYs have been determined for approximately 15 different fission products. The dual-fission chamber is a back-to-back ionization chamber system with a 'thin' actinide foil in each chamber as a monitor or reference foil. The chamber holds a 'thick' target in the center of the system such that the target and reference foils are of the same actinide isotope. This allows for simple mass scaling between the recorded number of fissions in the individual chambers and the number of fissions in the center thick target, eliminating the need for the knowledge of the absolute fission cross section and its uncertainty. The 'thick' target was removed after activation and gamma-rays counted with well shielded High Purity Germanium (HPGe) detectors for a period of 1.5 - 2 months.

  11. Fluorescence labelling of NADPH-cytochrome P-450 reductase with the monobromomethyl derivative of syn-9,10-dioxabimane.

    PubMed Central

    Vogel, F; Lumper, L

    1983-01-01

    The kinetics of thiol-group alkylation in NADPH-cytochrome P-450 reductase during its inactivation by monobromobimane has been studied using the fluorimetric determination of S-bimane-L-cysteine by high-performance liquid chromatography. Loss of activity during the reaction of NADPH-cytochrome P-450 reductase with monobromobimane is caused by the alkylation of one single critical cysteine residue, which can be protected against thiol-specific reagents by NADP(H). The chemical stability of the bimane group allows the digestion of bimane-labelled NADPH-cytochrome P-450 reductase by CNBr. The critical cysteine residue could be located in a CNBr-cleaved peptide purified to homogeneity with Mr 10 500 +/- 1 000 and valine as N-terminus. Images Fig. 2. PMID:6414464

  12. 48 CFR 235.010 - Scientific and technical reports.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... reports. 235.010 Section 235.010 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.010 Scientific and technical reports. (b) For DoD, the Defense Technical Information Center is...

  13. 48 CFR 235.010 - Scientific and technical reports.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... reports. 235.010 Section 235.010 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.010 Scientific and technical reports. (b) For DoD, the Defense Technical Information Center is...

  14. 48 CFR 235.010 - Scientific and technical reports.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... reports. 235.010 Section 235.010 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.010 Scientific and technical reports. (b) For DoD, the Defense Technical Information Center is...

  15. 48 CFR 235.010 - Scientific and technical reports.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... reports. 235.010 Section 235.010 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.010 Scientific and technical reports. (b) For DoD, the Defense Technical Information Center is...

  16. 48 CFR 235.010 - Scientific and technical reports.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... reports. 235.010 Section 235.010 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.010 Scientific and technical reports. (b) For DoD, the Defense Technical Information Center is...

  17. 7 CFR 916.235 - Delinquent assessments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Delinquent assessments. 916.235 Section 916.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE NECTARINES GROWN IN CALIFORNIA...

  18. 33 CFR 136.235 - Compensation allowable.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Compensation allowable. 136.235 Section 136.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS...

  19. 33 CFR 136.235 - Compensation allowable.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Compensation allowable. 136.235 Section 136.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS...

  20. 33 CFR 136.235 - Compensation allowable.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Compensation allowable. 136.235 Section 136.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS...

  1. 33 CFR 136.235 - Compensation allowable.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Compensation allowable. 136.235 Section 136.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS...

  2. 33 CFR 136.235 - Compensation allowable.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Compensation allowable. 136.235 Section 136.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS...

  3. 24 CFR 235.1001 - Providing information.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Providing information. 235.1001 Section 235.1001 Housing and Urban Development Regulations Relating to Housing and Urban Development... URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES...

  4. 24 CFR 235.1212 - Mortgage provisions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Mortgage provisions. 235.1212 Section 235.1212 Housing and Urban Development Regulations Relating to Housing and Urban Development... URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES...

  5. 21 CFR 314.235 - Judicial review.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Judicial review. 314.235 Section 314.235 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN... appeals under section 505(h) of the act. ...

  6. Design of a high-flux epithermal neutron beam using 235U fission plates at the Brookhaven Medical Research Reactor.

    PubMed

    Liu, H B; Brugger, R M; Rorer, D C; Tichler, P R; Hu, J P

    1994-10-01

    Beams of epithermal neutrons are being used in the development of boron neutron capture therapy for cancer. This report describes a design study in which 235U fission plates and moderators are used to produce an epithermal neutron beam with higher intensity and better quality than the beam currently in use at the Brookhaven Medical Research Reactor (BMRR). Monte Carlo calculations are used to predict the neutron and gamma fluxes and absorbed doses produced by the proposed design. Neutron flux measurements at the present epithermal treatment facility (ETF) were made to verify and compare with the computed results where feasible. The calculations indicate that an epithermal neutron beam produced by a fission-plate converter could have an epithermal neutron intensity of 1.2 x 10(10) n/cm2.s and a fast neutron dose per epithermal neutron of 2.8 x 10(-11) cGy.cm2/nepi plus being forward directed. This beam would be built into the beam shutter of the ETF at the BMRR. The feasibility of remodeling the facility is discussed.

  7. Physical Studies of P450–P450 Interactions: Predicting Quaternary Structures of P450 Complexes in Membranes from Their X-ray Crystal Structures

    PubMed Central

    Reed, James R.; Backes, Wayne L.

    2017-01-01

    Cytochrome P450 enzymes, which catalyze oxygenation reactions of both exogenous and endogenous chemicals, are membrane bound proteins that require interaction with their redox partners in order to function. Those responsible for drug and foreign compound metabolism are localized primarily in the endoplasmic reticulum of liver, lung, intestine, and other tissues. More recently, the potential for P450 enzymes to exist as supramolecular complexes has been shown by the demonstration of both homomeric and heteromeric complexes. The P450 units in these complexes are heterogeneous with respect to their distribution and function, and the interaction of different P450s can influence P450-specific metabolism. The goal of this review is to examine the evidence supporting the existence of physical complexes among P450 enzymes. Additionally, the review examines the crystal lattices of different P450 enzymes derived from X-ray diffraction data to make assumptions regarding possible quaternary structures in membranes and in turn, to predict how the quaternary structures could influence metabolism and explain the functional effects of specific P450–P450 interactions. PMID:28194112

  8. 45 CFR 618.235 - Statutory amendments.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Statutory amendments. 618.235 Section 618.235 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... of facilities, necessary to save the life of a pregnant woman or to address complications related to...

  9. 39 CFR 235.2 - Civil preparedness.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 39 Postal Service 1 2013-07-01 2013-07-01 false Civil preparedness. 235.2 Section 235.2 Postal... Civil preparedness. (a) Mission. The prime objective of postal emergency preparedness planning is to... programs: (1) National Civil Preparedness and Defense Mobilization; (2) Natural Disaster Preparedness; (3...

  10. 39 CFR 235.2 - Civil preparedness.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Civil preparedness. 235.2 Section 235.2 Postal... Civil preparedness. (a) Mission. The prime objective of postal emergency preparedness planning is to... programs: (1) National Civil Preparedness and Defense Mobilization; (2) Natural Disaster Preparedness; (3...

  11. 39 CFR 235.2 - Civil preparedness.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 39 Postal Service 1 2012-07-01 2012-07-01 false Civil preparedness. 235.2 Section 235.2 Postal... Civil preparedness. (a) Mission. The prime objective of postal emergency preparedness planning is to... programs: (1) National Civil Preparedness and Defense Mobilization; (2) Natural Disaster Preparedness; (3...

  12. 39 CFR 235.2 - Civil preparedness.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 39 Postal Service 1 2011-07-01 2011-07-01 false Civil preparedness. 235.2 Section 235.2 Postal... Civil preparedness. (a) Mission. The prime objective of postal emergency preparedness planning is to... programs: (1) National Civil Preparedness and Defense Mobilization; (2) Natural Disaster Preparedness; (3...

  13. 39 CFR 235.2 - Civil preparedness.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 39 Postal Service 1 2014-07-01 2014-07-01 false Civil preparedness. 235.2 Section 235.2 Postal... Civil preparedness. (a) Mission. The prime objective of postal emergency preparedness planning is to... programs: (1) National Civil Preparedness and Defense Mobilization; (2) Natural Disaster Preparedness; (3...

  14. 24 CFR 901.235 - Technical assistance.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Technical assistance. 901.235... DEVELOPMENT PUBLIC HOUSING MANAGEMENT ASSESSMENT PROGRAM § 901.235 Technical assistance. (a) The Department may provide technical assistance to a PHA that is in substantial default. (b) The Department may...

  15. 24 CFR 235.230 - Condition of multifamily structure.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Condition of multifamily structure. 235.230 Section 235.230 Housing and Urban Development Regulations Relating to Housing and Urban... Involving Condominium Units § 235.230 Condition of multifamily structure. (a) When a family unit is conveyed...

  16. 24 CFR 235.230 - Condition of multifamily structure.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Condition of multifamily structure. 235.230 Section 235.230 Housing and Urban Development Regulations Relating to Housing and Urban... Involving Condominium Units § 235.230 Condition of multifamily structure. (a) When a family unit is conveyed...

  17. 24 CFR 235.230 - Condition of multifamily structure.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Condition of multifamily structure. 235.230 Section 235.230 Housing and Urban Development Regulations Relating to Housing and Urban... Involving Condominium Units § 235.230 Condition of multifamily structure. (a) When a family unit is conveyed...

  18. 7 CFR 58.235 - Modified dry milk products.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Modified dry milk products. 58.235 Section 58.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Materials § 58.235 Modified dry milk products. Dry milk products to which approved neutralizing agents or...

  19. 7 CFR 58.235 - Modified dry milk products.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Modified dry milk products. 58.235 Section 58.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Materials § 58.235 Modified dry milk products. Dry milk products to which approved neutralizing agents or...

  20. 7 CFR 58.235 - Modified dry milk products.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Modified dry milk products. 58.235 Section 58.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Materials § 58.235 Modified dry milk products. Dry milk products to which approved neutralizing agents or...

  1. 7 CFR 58.235 - Modified dry milk products.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Modified dry milk products. 58.235 Section 58.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Materials § 58.235 Modified dry milk products. Dry milk products to which approved neutralizing agents or...

  2. 7 CFR 58.235 - Modified dry milk products.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Modified dry milk products. 58.235 Section 58.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Materials § 58.235 Modified dry milk products. Dry milk products to which approved neutralizing agents or...

  3. Radius anomaly in the diffraction model for heavy-ion elastic scattering

    NASA Astrophysics Data System (ADS)

    Pandey, L. N.; Mukherjee, S. N.

    1984-04-01

    The elastic scattering of heavy ions, 20Ne on 208Pb, 20Ne on 235U, 84Kr on 208Pb, and 84Kr on 232Th, is examined within the framework of Frahn's diffraction model. An analysis of the experiment using the "quarter point recipe" of the expected Fresnel cross sections yields a larger radius for 208Pb than the radii for 235U and 232Th. It is shown that inclusion of the nuclear deformation in the model removes the above anomaly in the radii, and the assumption of smooth cutoff of the angular momentum simultaneously leads to a better fit to elastic scattering data, compared to those obtained by the earlier workers on the assumption of sharp cutoff. [NUCLEAR REACTIONS Elastic scattering, 20Ne+208Pb (161.2 MeV), 20Ne+235U (175 MeV), 84Kr+208Pb (500 MeV), 84Kr+232Th (500 MeV), diffraction model, nuclear deformation.

  4. 32 CFR 235.7 - Information requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Information requirements. 235.7 Section 235.7 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED... Chair of the Board shall submit to the PDUSD(P&R) an annual report documenting the activities, decisions...

  5. 24 CFR 235.320 - Limitation of sales price.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Limitation of sales price. 235.320 Section 235.320 Housing and Urban Development Regulations Relating to Housing and Urban Development... Payments-Homes for Lower Income Families § 235.320 Limitation of sales price. To qualify for assistance...

  6. 24 CFR 235.320 - Limitation of sales price.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Limitation of sales price. 235.320 Section 235.320 Housing and Urban Development Regulations Relating to Housing and Urban Development... Payments-Homes for Lower Income Families § 235.320 Limitation of sales price. To qualify for assistance...

  7. 8 CFR 235.6 - Referral to immigration judge.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Referral to immigration judge. 235.6 Section 235.6 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS INSPECTION OF PERSONS APPLYING FOR ADMISSION § 235.6 Referral to immigration judge. (a) Notice—(1) Referral by Form I...

  8. Experimental modeling of Au and Pt coupled transport by chloride hydrothermal fluids at 350-450°C and 500-1000 bar

    NASA Astrophysics Data System (ADS)

    Zotov, A. V.; Tagirov, B. R.; Koroleva, L. A.; Volchenkova, V. A.

    2017-09-01

    The coupled solubility of Au(cr) and Pt(cr) has been measured in acidic chloride solutions at 350-450°C and 0.5 and 1 kb using the autoclave technique with determination of dissolved metal contents after quenching. The constants of the reaction combining the dominant species of Au and Pt in high-temperature hydrothermal fluids ( K (Au-Pt)) have been determined: 2 Au(cr) + PtCl4 2- = Pt(cr) + 2AuCl2 -; log K (Au-Pt) =-1.02 ± 0.25 (450°C, 1 kb), 0.09 ± 0.15 (450°C, 0.5 kb), and -1.31 ± 0.20 (350°C, 1 kb). It has been established that the factors affecting the Au/Pt concentration ratio in hydrothermal fluids and precipitated ores are temperature, pressure, redox potential, and sulfur fugacity. An increase in temperature results in an increase in the Au/Pt concentration ratio (up to 550°C at P = 1 kb). A decrease in pressure and redox potential leads to enrichment of fluid in Au. An increase in sulfur fugacity in the stability field of Pt sulfides results in increase in the Au/Pt concentration ratio. Native platinum is replaced by sulfide mineral in low-temperature systems enriched in Pt (relative to Au).

  9. 24 CFR 968.235 - Time extensions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Time extensions. 968.235 Section... Fewer Than 250 Units) § 968.235 Time extensions. A PHA shall not obligate or expend funds after the... time extension, as follows: (a) Certification. A PHA may extend an obligation or expenditure deadline...

  10. 24 CFR 968.235 - Time extensions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Time extensions. 968.235 Section... Fewer Than 250 Units) § 968.235 Time extensions. A PHA shall not obligate or expend funds after the... time extension, as follows: (a) Certification. A PHA may extend an obligation or expenditure deadline...

  11. 24 CFR 968.235 - Time extensions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Time extensions. 968.235 Section... Fewer Than 250 Units) § 968.235 Time extensions. A PHA shall not obligate or expend funds after the... time extension, as follows: (a) Certification. A PHA may extend an obligation or expenditure deadline...

  12. 24 CFR 968.235 - Time extensions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Time extensions. 968.235 Section... Fewer Than 250 Units) § 968.235 Time extensions. A PHA shall not obligate or expend funds after the... time extension, as follows: (a) Certification. A PHA may extend an obligation or expenditure deadline...

  13. A 7.2 keV spherical crystal backlighter system for Sandia's Z Pulsed Power Facility

    NASA Astrophysics Data System (ADS)

    Schollmeier, M.; Knapp, P. F.; Ampleford, D. J.; Loisel, G. P.; Robertson, G.; Shores, J. E.; Smith, I. C.; Speas, C. S.; Porter, J. L.; McBride, R. D.

    2016-10-01

    Many experiments on Sandia's Z facility, a 30 MA, 100 ns rise-time, pulsed-power driver, use a monochromatic Quartz crystal imaging backlighter system at 1.865 keV (Si Heα) or 6.151 keV (Mn Heα) x-ray energy to radiograph an imploding liner (cylindrical tube) or wire array. The x-ray source is generated by the Z-Beamlet Laser (ZBL), which provides up to 4.5 kJ at 527 nm during a 6 ns window. Radiographs of an imploding thick-walled Beryllium liner at a convergence ratio of about 20 [CR =Rin . (0) /Rin . (t) ] were too opaque to identify the inner surface of the liner with high confidence, demonstrating the need for a higher-energy x-ray backlighter between 6 and 10 keV. We present the design, test and first application of a Ge (335) spherical crystal x-ray backlighter system using the 7.242 keV Co Heα resonance line. The system operates at an almost identical Bragg angle as the existing 1.865 and 6.151 keV backlighters, enhancing our capabilities such as two-color, two-frame radiography, without changing detector shielding hardware. SAND No: SAND2016-6724 A. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. DoE NNSA under contract DE-AC04-94AL85000.

  14. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  15. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  16. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  17. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  18. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  19. 48 CFR 235.072 - Additional contract clauses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... contracts for research and development. (d) Use the clause at 252.235-7011, Final Scientific or Technical Report, in solicitations and contracts for research and development. (e) Use the clause at 252.235-7004...

  20. 48 CFR 235.070 - Indemnification against unusually hazardous risks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Indemnification against unusually hazardous risks. 235.070 Section 235.070 Federal Acquisition Regulations System DEFENSE... DEVELOPMENT CONTRACTING 235.070 Indemnification against unusually hazardous risks. ...

  1. Polarized BRDF measurement of the type E235B low carbon structural steel

    NASA Astrophysics Data System (ADS)

    Liu, Yanlei; Yu, Kun; Zhang, Kaihua; Liu, Yufang

    2018-01-01

    Bidirectional reflectance distribution function (BRDF) offers complete description of the spectral and spatial characteristics of opaque materials. The polarized BRDF contains more information, especially for the painted objects and target recognition. In this letter, we measured the in plane polarized spectral BRDF for the steel E235B in the wavelength range of 450-600 nm. The reliability of our results is verified by comparing the experimental data of polytetrafluoroethylene with the reference data. The measuring results indicates that the wavelength of incident light has a positive effect on the BRDF near the specular direction, and has a negative influence for other direction. BRDF increases slowly with reflected zenith angle and decreases rapidly with peak occurs at specular direction, which may be attributed to the shadowing effect. In addition, the results presents that the polarization of incident light has a slight influence on the BRDF of the sample.

  2. 31 CFR 500.571 - Transactions related to telecommunications authorized.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... telecommunications authorized. 500.571 Section 500.571 Money and Finance: Treasury Regulations Relating to Money and... telecommunications authorized. All transactions of U.S. common carriers incident to the receipt or transmission of telecommunications involving North Korea are authorized. Note: Exports or reexports to North Korea of goods and...

  3. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication.

    PubMed

    Lee, Changmin; Zhang, Chong; Cantore, Michael; Farrell, Robert M; Oh, Sang Ho; Margalith, Tal; Speck, James S; Nakamura, Shuji; Bowers, John E; DenBaars, Steven P

    2015-06-15

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature.

  4. 14 CFR 21.500 - Approval of engines and propellers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Approval of engines and propellers. 21.500 Section 21.500 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... propeller— (a) Conforms to its U.S. type certificate and is in condition for safe operation; and (b) Has...

  5. 7 CFR 205.208-205.235 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false [Reserved] 205.208-205.235 Section 205.208-205.235 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) ORGANIC FOODS PRODUCTION ACT...

  6. 8 CFR 235.3 - Inadmissible aliens and expedited removal.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 8 Aliens and Nationality 1 2013-01-01 2013-01-01 false Inadmissible aliens and expedited removal. 235.3 Section 235.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS INSPECTION OF PERSONS APPLYING FOR ADMISSION § 235.3 Inadmissible aliens and expedited removal. (a) Detention...

  7. 8 CFR 235.3 - Inadmissible aliens and expedited removal.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Inadmissible aliens and expedited removal. 235.3 Section 235.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS INSPECTION OF PERSONS APPLYING FOR ADMISSION § 235.3 Inadmissible aliens and expedited removal. (a) Detention...

  8. 8 CFR 235.3 - Inadmissible aliens and expedited removal.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Inadmissible aliens and expedited removal. 235.3 Section 235.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS INSPECTION OF PERSONS APPLYING FOR ADMISSION § 235.3 Inadmissible aliens and expedited removal. (a) Detention...

  9. 48 CFR 2052.235-70 - Publication of research results.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... results. 2052.235-70 Section 2052.235-70 Federal Acquisition Regulations System NUCLEAR REGULATORY....235-70 Publication of research results. As prescribed in 2035.70(a)(1), the contracting officer shall... Research Results (OCT 1999) (a) The principal investigator(s)/contractor shall comply with the provisions...

  10. 48 CFR 2052.235-70 - Publication of research results.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... results. 2052.235-70 Section 2052.235-70 Federal Acquisition Regulations System NUCLEAR REGULATORY....235-70 Publication of research results. As prescribed in 2035.70(a)(1), the contracting officer shall... Research Results (OCT 1999) (a) The principal investigator(s)/contractor shall comply with the provisions...

  11. 48 CFR 2052.235-70 - Publication of research results.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... results. 2052.235-70 Section 2052.235-70 Federal Acquisition Regulations System NUCLEAR REGULATORY....235-70 Publication of research results. As prescribed in 2035.70(a)(1), the contracting officer shall... Research Results (OCT 1999) (a) The principal investigator(s)/contractor shall comply with the provisions...

  12. 48 CFR 2917.500 - Scope of subpart.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CONTRACT TYPES SPECIAL CONTRACTING METHODS Interagency Acquisitions Under The Economy Act 2917.500 Scope of... of interagency acquisitions under the Economy Act (31 U.S.C. 1535) as prescribed by FAR 17.5. ...

  13. Decaying vector dark matter as an explanation for the 3.5 keV line from galaxy clusters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Farzan, Yasaman; Akbarieh, Amin Rezaei, E-mail: yasaman@theory.ipm.ac.ir, E-mail: am_rezaei@physics.sharif.ir

    2014-11-01

    We present a Vector Dark Matter (VDM) model that explains the 3.5 keV line recently observed in the XMM-Newton observatory data from galaxy clusters. In this model, dark matter is composed of two vector bosons, V and V', which couple to the photon through an effective generalized Chern-Simons coupling, g{sub V}. V' is slightly heavier than V with a mass splitting m{sub V'} – m{sub V} ≅ 3.5 keV. The decay of V' to V and a photon gives rise to the 3.5 keV line. The production of V and V' takes place in the early universe within the freeze-in framework through the effectivemore » g{sub V} coupling when m{sub V'} < T < Λ, Λ being the cut-off above which the effective g{sub V} coupling is not valid. We introduce a high energy model that gives rise to the g{sub V} coupling at low energies. To do this, V and V' are promoted to gauge bosons of spontaneously broken new U(1){sub V} and U(1){sub V'} gauge symmetries, respectively. The high energy sector includes milli-charged chiral fermions that lead to the g{sub V} coupling at low energy via triangle diagrams.« less

  14. Surface discharge related properties of fiberglass reinforced plastic insulator for use in neutral beam injector of JT-60U.

    PubMed

    Yamano, Y; Takahashi, M; Kobayashi, S; Hanada, M; Ikeda, Y

    2008-02-01

    Neutral beam injection (NBI) used for JT-60U is required to generate negative ions of 500 keV energies. To produce such high-energy ions, three-stage electrostatic accelerators consisting of three insulator rings made of fiberglass reinforced plastic (FRP) are applied. The surface discharges along FRP insulators are one of the most serious problems in the development of NBI. To increase the hold-off voltage against surface flashover events, it is necessary to investigate the FRP insulator properties related to surface discharges in vacuum. This paper describes surface flashover characteristics for FRP and alumina samples under vacuum condition. The results show that the fold-off voltages for FRP samples are inferior to those of alumina ceramics. In addition, measurement results of surface resistivity and volume resistivity under vacuum and atmospheric conditions, secondary electron emission characteristics, and cathodoluminescence under some keV electron beam irradiation are also reported. These are important parameters to analyze surface discharge of insulators in vacuum.

  15. Identification of a cytochrome P450 gene in the earthworm Eisenia fetida and its mRNA expression under enrofloxacin stress.

    PubMed

    Li, Yinsheng; Zhao, Chun; Lu, Xiaoxu; Ai, Xiaojie; Qiu, Jiangping

    2018-04-15

    Cytochrome P450 (CYP450) enzymes are a family of hemoproteins primarily responsible for detoxification functions. Earthworms have been used as a bioindicator of soil pollution in numerous studies, but no CYP450 gene has so far been cloned. RT-PCR and RACE-PCR were employed to construct and sequence the CYP450 gene DNA from the extracted mRNA in the earthworm Eisenia fetida. The cloned gene (EW1) has an open reading frame of 477bp. The 3'-terminal region contained both the consensus and the signature sequences characteristic of CYP450. It was closely related to the CYP450 gene from the flatworm genus Opisthorchis felineus with 87% homology. The predicted structure of the putative protein was 97% homologous to human CYP450 family 27. This gene has been deposited in GenBank (accession no. KM881474). Earthworms (E. fetida) were then exposed to 1, 10, 100, and 500mgkg -1 enrofloxacin in soils to explore the mRNA expression by real time qPCR. The effect of enrofloxacin on mRNA expression levels of EW1 exhibited a marked hormesis pattern across the enrofloxacin dose range tested. This is believed to be the first reported CYP450 gene in earthworms, with reference value for molecular studies on detoxification processes in earthworms. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. 48 CFR 235.017-1 - Sponsoring agreements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Sponsoring agreements. 235.017-1 Section 235.017-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM... Sponsoring agreements. (c)(4) DoD-sponsoring FFRDCs that function primarily as research laboratories (C3I...

  17. 24 CFR 1006.235 - Types of investments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Types of investments. 1006.235... DEVELOPMENT NATIVE HAWAIIAN HOUSING BLOCK GRANT PROGRAM Eligible Activities § 1006.235 Types of investments... use NHHBG funds for affordable housing activities in the form of equity investments, interest-bearing...

  18. 2 CFR 1401.235 - Drug-free workplace.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2 Grants and Agreements 1 2011-01-01 2011-01-01 false Drug-free workplace. 1401.235 Section 1401.235 Grants and Agreements Federal Agency Regulations for Grants and Agreements DEPARTMENT OF THE INTERIOR REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) (Eff. 1-21-2011) Definitions § 1401...

  19. 12 CFR 235.8 - Reporting requirements and record retention.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .... 235.8 Section 235.8 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE... the requirements of this part under § 235.5(a) and each payment card network shall file a report with the Board in accordance with this section. (b) Report. Each entity required to file a report with the...

  20. 12 CFR 235.8 - Reporting requirements and record retention.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... 235.8 Section 235.8 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE... the requirements of this part under § 235.5(a) and each payment card network shall file a report with the Board in accordance with this section. (b) Report. Each entity required to file a report with the...

  1. 12 CFR 235.8 - Reporting requirements and record retention.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .... 235.8 Section 235.8 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE... the requirements of this part under § 235.5(a) and each payment card network shall file a report with the Board in accordance with this section. (b) Report. Each entity required to file a report with the...

  2. Electrochemistry of cytochrome P450 17α-hydroxylase/17,20-lyase (P450c17).

    PubMed

    Martin, Lisandra L; Kubeil, Clemens; Simonov, Alexandr N; Kuznetsov, Vladimir L; Corbin, C Jo; Auchus, Richard J; Conley, Alan J; Bond, Alan M; Rodgers, Raymond J

    2017-02-05

    Within the superfamily of cytochrome P450 enzymes (P450s), there is a small class which is functionally employed for steroid biosynthesis. The enzymes in this class appear to have a small active site to accommodate the steroid substrates specifically and snuggly, prior to the redox transformation or hydroxylation to form a product. Cytochrome P450c17 is one of these and is also a multi-functional P450, with two activities, the first 17α-hydroxylation of pregnenolone is followed by a subsequent 17,20-lyase transformation to dehydroepiandrosterone (DHEA) as the dominant pathways to cortisol precursors or androgens in humans, respectively. How P450c17 regulates these two redox reactions is of special interest. There is a paucity of direct electrochemical studies on steroidogenic P450s, and in this mini-review we provide an overview of these studies with P450c17. Historical consideration as to the difficulties in obtaining reliable electrochemistry due to issues of handling proteins on an electrode, together with advances in the electrochemical techniques are addressed. Recent work using Fourier transformed alternating current voltammetry is highlighted as this technique can provide both catalytic information simultaneously with the underlying redox transfer with the P450 haem. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Inelastic neutron scattering from {sup 238}U

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Moxon, M.C.; Wartena, J.A.; Weigmann, H.

    1994-12-31

    A measurement of the neutron inelastic scattering cross-section of {sup 238}U at 4 distant neutron energies in the low keV region has been undertaken using a 30m flight path on the pulsed neutron source GELINA. The scattered neutrons are detected in a plastic scintillator after passing through a 270 mm iron filter. The values obtained for the cross-section to the first excited 2{sup +} state in {sup 238}U are 293{+-}31, 660{+-}296, 978{+-}73 and 1176{+-}95 mb at neutron energies of 68.2, 126.6, 182.4 and 213.6 keV respectively.

  4. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  5. 23 CFR 450.102 - Applicability.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Applicability. 450.102 Section 450.102 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.102 Applicability. The definitions in...

  6. 23 CFR 450.102 - Applicability.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Applicability. 450.102 Section 450.102 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.102 Applicability. The definitions in...

  7. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  8. 23 CFR 450.204 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Definitions. 450.204 Section 450.204 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.204 Definitions. Except as otherwise...

  9. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  10. 23 CFR 450.204 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Definitions. 450.204 Section 450.204 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.204 Definitions. Except as otherwise...

  11. 23 CFR 450.300 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Purpose. 450.300 Section 450.300 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.300 Purpose. The purposes of this...

  12. 23 CFR 450.300 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Purpose. 450.300 Section 450.300 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.300 Purpose. The purposes of this...

  13. 23 CFR 450.102 - Applicability.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Applicability. 450.102 Section 450.102 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.102 Applicability. The definitions in...

  14. 23 CFR 450.202 - Applicability.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Applicability. 450.202 Section 450.202 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.202 Applicability. The provisions of this...

  15. 23 CFR 450.202 - Applicability.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Applicability. 450.202 Section 450.202 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.202 Applicability. The provisions of this...

  16. 23 CFR 450.204 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Definitions. 450.204 Section 450.204 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.204 Definitions. Except as otherwise...

  17. 23 CFR 450.300 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Purpose. 450.300 Section 450.300 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.300 Purpose. The purposes of this...

  18. 23 CFR 450.202 - Applicability.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Applicability. 450.202 Section 450.202 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.202 Applicability. The provisions of this...

  19. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  20. 23 CFR 450.204 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Definitions. 450.204 Section 450.204 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.204 Definitions. Except as otherwise...

  1. 23 CFR 450.300 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Purpose. 450.300 Section 450.300 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.300 Purpose. The purposes of this...

  2. 23 CFR 450.102 - Applicability.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Applicability. 450.102 Section 450.102 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.102 Applicability. The definitions in...

  3. 23 CFR 450.204 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Definitions. 450.204 Section 450.204 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.204 Definitions. Except as otherwise...

  4. 23 CFR 450.300 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Purpose. 450.300 Section 450.300 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.300 Purpose. The purposes of this...

  5. 23 CFR 450.202 - Applicability.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Applicability. 450.202 Section 450.202 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.202 Applicability. The provisions of this...

  6. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  7. 23 CFR 450.102 - Applicability.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Applicability. 450.102 Section 450.102 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.102 Applicability. The definitions in...

  8. 2 CFR 1401.235 - Drug-free workplace.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2 Grants and Agreements 1 2012-01-01 2012-01-01 false Drug-free workplace. 1401.235 Section 1401... INTERIOR REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Definitions § 1401.235 Drug-free workplace. Drug-free workplace means a site for the performance of work done in connection with a specific...

  9. 2 CFR 1401.235 - Drug-free workplace.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2 Grants and Agreements 1 2013-01-01 2013-01-01 false Drug-free workplace. 1401.235 Section 1401... INTERIOR REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Definitions § 1401.235 Drug-free workplace. Drug-free workplace means a site for the performance of work done in connection with a specific...

  10. 12 CFR 235.4 - Fraud-prevention adjustment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 4 2012-01-01 2012-01-01 false Fraud-prevention adjustment. 235.4 Section 235.4 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE... in paragraph (b) of this section must certify such compliance to its payment card networks on an...

  11. 23 CFR 450.200 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Purpose. 450.200 Section 450.200 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.200 Purpose. The purpose of this subpart...

  12. 23 CFR 450.200 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Purpose. 450.200 Section 450.200 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.200 Purpose. The purpose of this subpart...

  13. 23 CFR 450.100 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Purpose. 450.100 Section 450.100 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.100 Purpose. The purpose of this subpart...

  14. 23 CFR 450.100 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Purpose. 450.100 Section 450.100 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.100 Purpose. The purpose of this subpart...

  15. 23 CFR 450.200 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Purpose. 450.200 Section 450.200 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.200 Purpose. The purpose of this subpart...

  16. 23 CFR 450.100 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Purpose. 450.100 Section 450.100 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.100 Purpose. The purpose of this subpart...

  17. 23 CFR 450.100 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Purpose. 450.100 Section 450.100 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.100 Purpose. The purpose of this subpart...

  18. 23 CFR 450.200 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Purpose. 450.200 Section 450.200 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.200 Purpose. The purpose of this subpart...

  19. 23 CFR 450.100 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Purpose. 450.100 Section 450.100 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Transportation Planning and Programming Definitions § 450.100 Purpose. The purpose of this subpart...

  20. 23 CFR 450.200 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Purpose. 450.200 Section 450.200 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Statewide Transportation Planning and Programming § 450.200 Purpose. The purpose of this subpart...

  1. 24 CFR 8.29 - Homeownership programs (sections 235(i) and 235(j), Turnkey III and Indian housing mutual self...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Homeownership programs (sections 235(i) and 235(j), Turnkey III and Indian housing mutual self-help programs). 8.29 Section 8.29...), Turnkey III and Indian housing mutual self-help programs). Any housing units newly constructed or...

  2. 24 CFR 8.29 - Homeownership programs (sections 235(i) and 235(j), Turnkey III and Indian housing mutual self...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Homeownership programs (sections 235(i) and 235(j), Turnkey III and Indian housing mutual self-help programs). 8.29 Section 8.29...), Turnkey III and Indian housing mutual self-help programs). Any housing units newly constructed or...

  3. EVIDENCE FOR BROMODICHLOROMETHANE METABOLISM BY CYTOCHROME P-450 1A2

    EPA Science Inventory

    EVIDENCE FOR BROMODICHLOROMETHANE METABOLISM BY CYTOCHROME P-450 1A2. T M Ross1, B P Anderson1, G Zhao2, R A Pegram1 and J W Allis1. 1U.S. EPA, ORD, NHEERL, Research Triangle Park, NC; 2University of North Carolina, Chapel Hill, NC.
    Sponsor: H Barton

    Bromodichlorometh...

  4. 40 CFR 450.10 - Applicability.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability. 450.10 Section 450.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CONSTRUCTION AND DEVELOPMENT POINT SOURCE CATEGORY General Provisions § 450.10 Applicability. (a) This part applies to discharges associated with...

  5. 500 keV Ar2+ ion irradiation induced anatase to brookite phase transformation and ferromagnetism at room temperature in TiO2 thin films

    NASA Astrophysics Data System (ADS)

    Bharati, B.; Mishra, N. C.; Kanjilal, D.; Rath, Chandana

    2018-01-01

    In our earlier report, where we have demonstrated ferromagnetic behavior at room temperature (RT) in TiO2 thin films deposited through electron beam evaporation technique followed by annealing either in Ar or O2 atmosphere [Mohanty et al., Journal of Magnetism and Magnetic Materials 355 (2014) 240-245], here we have studied the evolution of structure and magnetic properties after irradiating the TiO2 thin films with 500 keV Ar2+ ions. The pristine film while exhibits anatase phase, the films become amorphous after irradiating at fluence in the range 1 × 1014 to 1 × 1016 ions/cm2. Increasing the fluence up to 5 × 1016 ions/cm2, amorphous to crystalline phase transformation occurs and the structure becomes brookite. Although anatase to rutile phase transformation is usually reported in literatures, anatase to brookite phase transformation is an unusual feature which we have reported here for the first time. Such anatase to brookite phase transformation is accompanied with grain growth without showing any change in film thickness evidenced from Rutherford's Back Scattering (RBS) measurement. From scanning probe micrographs (SPM), roughness is found to be more in amorphous films than in the crystalline ones. Anatase to brookite phase transformation could be realized by considering the importance of intermediate amorphous phase. Because due to amorphous phase, heat deposited by energetic ions are localized as dissipation of heat is less and as a result, the localized region crystallizes in brookite phase followed by grain growth as observed in highest fluence. Further, we have demonstrated ferromagnetic behavior at RT in irradiated films similar to pristine one, irrespective of their phase and crystallinity. Origin for room temperature ferromagnetism (RTFM) is attributed to the presence of oxygen vacancies which is confirmed by carrying out XPS measurement.

  6. 42 CFR 405.450 - Appeals.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Appeals. 405.450 Section 405.450 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM FEDERAL HEALTH INSURANCE FOR THE AGED AND DISABLED Private Contracts § 405.450 Appeals. (a) A determination by...

  7. 48 CFR 23.500 - Scope of subpart.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Drug-Free Workplace 23.500 Scope of subpart. This subpart implements 41 U.S.C. chapter 81, Drug-Free Workplace. [79 FR 24208, Apr. 29, 2014] ...

  8. Alternate Multilayer Gratings with Enhanced Diffraction Efficiency in the 500-5000 eV Energy Domain

    NASA Astrophysics Data System (ADS)

    Polack, François; Lagarde, Bruno; Idir, Mourad; Cloup, Audrey Liard; Jourdain, Erick; Roulliay, Marc; Delmotte, Franck; Gautier, Julien; Ravet-Krill, Marie-Françoise

    2007-01-01

    An alternate multilayer (AML) grating is a 2 dimensional diffraction structure formed on an optical surface, having a 0.5 duty cycle in the in-plane and in the in-depth direction. It can be made by covering a shallow depth laminar grating with a multilayer stack. We show here that their 2D structure confer AML gratings a high angular and energetic selectivity and therefore enhanced diffraction properties, when used in grazing incidence. In the tender X-ray range (500eV - 5000 eV) they behave much like blazed gratings. Over 15% efficiency has been measured on a 1200 lines/mm Mo/Si AML grating in the 1.2 - 1.5 keV energy range. Computer simulations show that selected multilayer materials such as Cr/C should allow diffraction efficiency over 50% at photon energies over 3 keV.

  9. 48 CFR 235.017 - Federally Funded Research and Development Centers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... and Development Centers. 235.017 Section 235.017 Federal Acquisition Regulations System DEFENSE... DEVELOPMENT CONTRACTING 235.017 Federally Funded Research and Development Centers. (a) Policy. (2) No DoD... Funded Research and Development Center (FFRDC) if a member of its board of directors or trustees...

  10. 48 CFR 235.017 - Federally Funded Research and Development Centers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... and Development Centers. 235.017 Section 235.017 Federal Acquisition Regulations System DEFENSE... DEVELOPMENT CONTRACTING 235.017 Federally Funded Research and Development Centers. (a) Policy. (2) No DoD... Funded Research and Development Center (FFRDC) if a member of its board of directors or trustees...

  11. 48 CFR 235.017 - Federally Funded Research and Development Centers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... and Development Centers. 235.017 Section 235.017 Federal Acquisition Regulations System DEFENSE... DEVELOPMENT CONTRACTING 235.017 Federally Funded Research and Development Centers. (a) Policy. (2) No DoD... Funded Research and Development Center (FFRDC) if a member of its board of directors or trustees...

  12. 48 CFR 235.017 - Federally Funded Research and Development Centers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... and Development Centers. 235.017 Section 235.017 Federal Acquisition Regulations System DEFENSE... DEVELOPMENT CONTRACTING 235.017 Federally Funded Research and Development Centers. (a) Policy. (2) No DoD... Funded Research and Development Center (FFRDC) if a member of its board of directors or trustees...

  13. 48 CFR 235.017 - Federally Funded Research and Development Centers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... and Development Centers. 235.017 Section 235.017 Federal Acquisition Regulations System DEFENSE... DEVELOPMENT CONTRACTING 235.017 Federally Funded Research and Development Centers. (a) Policy. (2) No DoD... Funded Research and Development Center (FFRDC) if a member of its board of directors or trustees...

  14. Evaluation of the 235U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Neudecker, Denise; Talou, Patrick; Kahler, Albert Comstock III

    We present an evaluation of the 235U prompt fission neutron spectrum (PFNS) induced by thermal to 20-MeV neutrons. Experimental data and associated covariances were analyzed in detail. The incident energy dependence of the PFNS was modeled with an extended Los Alamos model combined with the Hauser-Feshbach and the exciton models. These models describe prompt fission, pre-fission compound nucleus and pre-equilibrium neutron emissions. The evaluated PFNS agree well with the experimental data included in this evaluation, preliminary data of the LANL and LLNL Chi-Nu measurement and recent evaluations by Capote et al. and Rising et al. However, they are softer thanmore » the ENDF/B-VII.1 (VII.1) and JENDL-4.0 PFNS for incident neutron energies up to 2 MeV. Simulated effective multiplication factors k eff of the Godiva and Flattop-25 critical assemblies are further from the measured k eff if the current data are used within VII.1 compared to using only VII.1 data. However, if this work is used with ENDF/B-VIII.0β2 data, simulated values of k eff agree well with the measured ones.« less

  15. Evaluation of the 235U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

    DOE PAGES

    Neudecker, Denise; Talou, Patrick; Kahler, Albert Comstock III; ...

    2017-09-13

    We present an evaluation of the 235U prompt fission neutron spectrum (PFNS) induced by thermal to 20-MeV neutrons. Experimental data and associated covariances were analyzed in detail. The incident energy dependence of the PFNS was modeled with an extended Los Alamos model combined with the Hauser-Feshbach and the exciton models. These models describe prompt fission, pre-fission compound nucleus and pre-equilibrium neutron emissions. The evaluated PFNS agree well with the experimental data included in this evaluation, preliminary data of the LANL and LLNL Chi-Nu measurement and recent evaluations by Capote et al. and Rising et al. However, they are softer thanmore » the ENDF/B-VII.1 (VII.1) and JENDL-4.0 PFNS for incident neutron energies up to 2 MeV. Simulated effective multiplication factors k eff of the Godiva and Flattop-25 critical assemblies are further from the measured k eff if the current data are used within VII.1 compared to using only VII.1 data. However, if this work is used with ENDF/B-VIII.0β2 data, simulated values of k eff agree well with the measured ones.« less

  16. Evaluation of the 235U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

    NASA Astrophysics Data System (ADS)

    Neudecker, Denise; Talou, Patrick; Kahler, Albert C.; White, Morgan C.; Kawano, Toshihiko

    2017-09-01

    We present an evaluation of the 235U prompt fission neutron spectrum (PFNS) induced by thermal to 20-MeV neutrons. Experimental data and associated covariances were analyzed in detail. The incident energy dependence of the PFNS was modeled with an extended Los Alamos model combined with the Hauser-Feshbach and the exciton models. These models describe prompt fission, pre-fission compound nucleus and pre-equilibrium neutron emissions. The evaluated PFNS agree well with the experimental data included in this evaluation, preliminary data of the LANL and LLNL Chi-Nu measurement and recent evaluations by Capote et al. and Rising et al. However, they are softer than the ENDF/B-VII.1 (VII.1) and JENDL-4.0 PFNS for incident neutron energies up to 2 MeV. Simulated effective multiplication factors keff of the Godiva and Flattop-25 critical assemblies are further from the measured keff if the current data are used within VII.1 compared to using only VII.1 data. However, if this work is used with ENDF/B-VIII.0β2 data, simulated values of keff agree well with the measured ones.

  17. Ejection of nanoclusters from gold nanoislet layers by 38 keV Au ions in the elastic stopping mode.

    PubMed

    Baranov, I A; Della-Negra, S; Domaratsky, V P; Chemezov, A V; Kirillov, S N; Novikov, A C; Obnorsky, V V; Pautrat, M; Urbassek, H M; Wien, K; Yarmiychuk, S V; Zhurkin, E E

    2009-07-01

    Total absolute yields of the ejected gold were obtained regardless of the type of the particles are--atoms, clusters, nanoclusters,--as well as absolute yields of gold nanoclusters, from nanoislet gold targets under bombardment by monoatomic gold ions at 45 degrees to the target surface with the energy 38 keV, i.e., in the "purely" elastic stopping mode -6 keV/nm up to the fluence of 4 x 10(12) cm2. Three targets had gold nanoislets on the substrate surface: 2-12 nm; -18 nm; -35 nm, the most probable sizes being 7.1; 9.4; 17.5 nm respectively. The part of the surface area covered with gold was known. Total transfer of gold was determined by means of the neutron-activation analysis and decreased from 450 to 20 at/ion. The number of the ejected gold nanoclusters was determined using TEM and decreased from approximately 0.06 to < 0.01 per one 38 keV Au ion with the increase of the most probable sizes of the nanoislets on the target from 7.1 to 17.5 nm. The yields appeared to be surprisingly high, which is of scientific and practical importance. Tentative estimations were made using molecular dynamics simulations.

  18. 48 CFR 1552.235-71 - Treatment of confidential business information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... business information. 1552.235-71 Section 1552.235-71 Federal Acquisition Regulations System ENVIRONMENTAL... Clauses 1552.235-71 Treatment of confidential business information. As prescribed in 1535.007-70(b... determined that in the performance of a contract, EPA may furnish confidential business information to the...

  19. FTIR studies of the redox partner interaction in cytochrome P450: the Pdx-P450cam couple.

    PubMed

    Karyakin, Andrey; Motiejunas, Domantas; Wade, Rebecca C; Jung, Christiane

    2007-03-01

    Recently we have developed a new approach to study protein-protein interactions using Fourier transform infrared spectroscopy in combination with titration experiments and principal component analysis (FTIR-TPCA). In the present paper we review the FTIR-TPCA results obtained for the interaction between cytochrome P450 and the redox partner protein in two P450 systems, the Pseudomonas putida P450cam (CYP101) with putidaredoxin (P450cam-Pdx), and the Bacillus megaterium P450BM-3 (CYP102) heme domain with the FMN domain (P450BMP-FMND). Both P450 systems reveal similarities in the structural changes that occur upon redox partner complex formation. These involve an increase in beta-sheets and alpha-helix content, a decrease in the population of random coil/3(10)-helix structure, a redistribution of turn structures within the interacting proteins and changes in the protonation states or hydrogen-bonding of amino acid carboxylic side chains. We discuss in detail the P450cam-Pdx interaction in comparison with literature data and conclusions drawn from experiments obtained by other spectroscopic techniques. The results are also interpreted in the context of a 3D structural model of the Pdx-P450cam complex.

  20. Membrane-bound human orphan cytochrome P450 2U1: Sequence singularities, construction of a full 3D model, and substrate docking.

    PubMed

    Ducassou, Lionel; Dhers, Laura; Jonasson, Gabriella; Pietrancosta, Nicolas; Boucher, Jean-Luc; Mansuy, Daniel; André, François

    2017-09-01

    Human cytochrome P450 2U1 (CYP2U1) is an orphan CYP that exhibits several distinctive characteristics among the 57 human CYPs with a highly conserved sequence in almost all living organisms. We compared its protein sequence with those of the 57 human CYPs and constructed a 3D structure of a full-length CYP2U1 model bound to a POPC membrane. We also performed docking experiments of arachidonic acid (AA) and N-arachidonoylserotonin (AS) in this model. The protein sequence of CYP2U1 displayed two unique characteristics when compared to those of the human CYPs, the presence of a longer N-terminal region upstream of the putative trans-membrane helix (TMH) containing 8 proline residues, and of an insert of about 20 amino acids containing 5 arginine residues between helices A' and A. Its N-terminal part upstream of TMH involved an additional short terminal helix, in a manner similar to what was reported in the crystal structure of Saccharomyces cerevisiae CYP51. Our model also showed a specific interaction between the charged residues of insert AA' and phosphate groups of lipid polar heads, suggesting a possible role of this insert in substrate recruitment. Docking of AA and AS in this model showed these substrates in channel 2ac, with the terminal alkyl chain of AA or the indole ring of AS close to the heme, in agreement with the reported CYP2U1-catalyzed AA and AS hydroxylation regioselectivities. This model should be useful to find new endogenous or exogenous CYP2U1 substrates and to interpret the regioselectivity of their hydroxylation. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  1. Cytochromes P450

    PubMed Central

    Bak, Søren; Beisson, Fred; Bishop, Gerard; Hamberger, Björn; Höfer, René; Paquette, Suzanne; Werck-Reichhart, Danièle

    2011-01-01

    There are 244 cytochrome P450 genes (and 28 pseudogenes) in the Arabidopsis genome. P450s thus form one of the largest gene families in plants. Contrary to what was initially thought, this family diversification results in very limited functional redundancy and seems to mirror the complexity of plant metabolism. P450s sometimes share less than 20% identity and catalyze extremely diverse reactions leading to the precursors of structural macromolecules such as lignin, cutin, suberin and sporopollenin, or are involved in biosynthesis or catabolism of all hormone and signaling molecules, of pigments, odorants, flavors, antioxidants, allelochemicals and defense compounds, and in the metabolism of xenobiotics. The mechanisms of gene duplication and diversification are getting better understood and together with co-expression data provide leads to functional characterization. PMID:22303269

  2. 29 CFR 1952.235 - Level of Federal enforcement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Level of Federal enforcement. 1952.235 Section 1952.235 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Level of Federal enforcement. (a) As a result of the Assistant Secretary's determination granting final...

  3. Geology and mineral resource assessment of the Venezuelan Guayana Shield at 1:500,000 scale; a digital representation of maps published by the U.S. Geological Survey

    USGS Publications Warehouse

    Schruben, Paul G.; Wynn, J.C.; Gray, Floyd; Cox, D.P.; Sterwart, J.H.; Brooks, W.E.

    1997-01-01

    This CD-ROM contains vector-based digital maps of the geology and resource assessment of the Venezuela Guayana Shield originally published as paper maps in 1993 in U. S. Geological Survey Bulletin 2062, at a scale of 1:1 million and revised in 1993-95 as separate maps at a scale of 1:500,000. Although the maps on this disc can be displayed at different scales, they are not intended to be used at any scale more detailed than 1:500,000.

  4. 40 CFR 1036.235 - Testing requirements for certification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... 1036.235 Section 1036.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW AND IN-USE HEAVY-DUTY HIGHWAY ENGINES Certifying Engine..., subpart N. Engines certified for use in tractors may also be used in vocational vehicles; however, you may...

  5. 40 CFR 1036.235 - Testing requirements for certification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... 1036.235 Section 1036.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW AND IN-USE HEAVY-DUTY HIGHWAY ENGINES Certifying Engine..., subpart N. Engines certified for use in tractors may also be used in vocational vehicles; however, you may...

  6. 40 CFR 1036.235 - Testing requirements for certification.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... 1036.235 Section 1036.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW AND IN-USE HEAVY-DUTY HIGHWAY ENGINES Certifying Engine..., subpart N. Engines certified for use in tractors may also be used in vocational vehicles; however, you may...

  7. Demonstration of a 13 keV Kr K-shell X-Ray Source at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Fournier, K. B.; May, M. J.; Colvin, J. D.; Barrios, M. A.; Patterson, J. R.; Regan, S. P.

    2013-10-01

    We report 3% conversion efficiency of laser energy into Kr K-shell (~13 keV) radiation, consistent with theoretical predictions. This is ~10 × greater than previous work. The emission was produced from a 4.1 mm diameter, 4 mm tall gas pipe target filled with 1.2 or 1.5 atm of Kr gas. 160 of the NIF laser beams deposited ~700 kJ of 3 ω light into the target in a ~140 TW, 5.0 ns duration square pulse. This laser configuration sufficiently heated the targets to optimize the K-shell x-ray emission. The Dante diagnostics measured ~5 TW into 4 π solid angle of >=12 keV x rays for ~4 ns, which includes both continuum emission and flux in the Kr Heα line at 13 keV. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This work was supported by the Defense Threat Reduction Agency under the intera- gency agreements 10027-1420 and 10027-6167.

  8. Chronic effects of ethanol and/or darunavir/ritonavir on U937 monocytic cells: Regulation of cytochrome P450 and antioxidant enzymes, oxidative stress, and cytotoxicity

    PubMed Central

    Rao, P.S.S.; Kumar, Santosh

    2015-01-01

    Background Our recent study has shown that acute treatment with ethanol increases oxidative stress and cytotoxicity through cytochrome P450 2E1 (CYP2E1)-mediated pathway in U937 monocytic cells. U937 cells are derived from blood monocytes and are considered as the model system for HIV-related study. Since the prevalence of alcohol use in HIV-infected population is high, and HIV+ patients are on antiretroviral therapy (ART) soon after they are diagnosed, it is important to study the interactions between ethanol and ART in monocytes. Methods This study examined the chronic effects of ethanol and ART (darunavir/ritonavir), alone and in combination, on expression/levels of cytochrome P450 enzymes (CYPs), antioxidant enzymes (AOEs), reactive oxygen species (ROS), and cytotoxicity in U937 cells. The mRNA and protein levels were measured using quantitative RTPCR and Western blot, respectively. ROS and cytotoxicity were measured using flow cytometry and XTT assay, respectively. Results While chronic ART treatment increased CYP2E1 protein expression by 2-fold, ethanol and ethanol+ART increased CYP2E1 by ~5-fold. In contrast, ART and ethanol treatments decreased CYP3A4 protein expression by 38±17% and 74±15%, respectively, and the combination additively decreased CYP3A4 level by 90±8%. Expressions of superoxide dismutase (SOD1) and peroxiredoxin (PRDX6) were decreased by both ethanol and ART, however, the expressions of SOD2 and catalase were unaltered. These results suggested increased ethanol metabolism, increased ART accumulation, and decreased defense against ROS. Therefore, we determined the effects of ethanol and ART on ROS and cytotoxicity. While ART showed a slight increase, ethanol and ethanol+ART displayed significant increase in ROS and cytotoxicity. Moreover, the combination showed additive effects on ROS and cytotoxicity. Conclusions These results suggest that chronic ethanol, in the absence and presence of ART, increases ROS and cytotoxicity in monocytes

  9. An indole-deficient Escherichia coli strain improves screening of cytochromes P450 for biotechnological applications.

    PubMed

    Brixius-Anderko, Simone; Hannemann, Frank; Ringle, Michael; Khatri, Yogan; Bernhardt, Rita

    2017-05-01

    Escherichia coli has developed into an attractive organism for heterologous cytochrome P450 production, but, in some cases, was restricted as a host in view of a screening of orphan cytochromes P450 or mutant libraries in the context of molecular evolution due to the formation of the cytochrome P450 inhibitor indole by the enzyme tryptophanase (TnaA). To overcome this effect, we disrupted the tnaA gene locus of E. coli C43(DE3) and evaluated the new strain for whole-cell substrate conversions with three indole-sensitive cytochromes P450, myxobacterial CYP264A1, and CYP109D1 as well as bovine steroidogenic CYP21A2. For purified CYP264A1 and CYP21A2, the half maximal inhibitory indole concentration was determined to be 140 and 500 μM, which is within the physiological concentration range occurring during cultivation of E. coli in complex medium. Biotransformations with C43(DE3)_∆tnaA achieved a 30% higher product formation in the case of CYP21A2 and an even fourfold increase with CYP264A1 compared with C43(DE3) cells. In whole-cell conversion based on CYP109D1, which converts indole to indigo, we could successfully avoid this reaction. Results in microplate format indicate that our newly designed strain is a suitable host for a fast and efficient screening of indole-influenced cytochromes P450 in complex medium. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  10. P450 monooxygenases (P450ome) of the model white rot fungus Phanerochaete chrysosporium.

    PubMed

    Syed, Khajamohiddin; Yadav, Jagjit S

    2012-11-01

    Phanerochaete chrysosporium, the model white rot fungus, has been the focus of research for the past about four decades for understanding the mechanisms and processes of biodegradation of the natural aromatic polymer lignin and a broad range of environmental toxic chemicals. The ability to degrade this vast array of xenobiotic compounds was originally attributed to its lignin-degrading enzyme system, mainly the extracellular peroxidases. However, subsequent physiological, biochemical, and/or genetic studies by us and others identified the involvement of a peroxidase-independent oxidoreductase system, the cytochrome P450 monooxygenase system. The whole genome sequence revealed an extraordinarily large P450 contingent (P450ome) with an estimated 149 P450s in this organism. This review focuses on the current status of understanding on the P450 monooxygenase system of P. chrysosproium in terms of pre-genomic and post-genomic identification, structural and evolutionary analysis, transcriptional regulation, redox partners, and functional characterization for its biodegradative potential. Future research on this catalytically diverse oxidoreductase enzyme system and its major role as a newly emerged player in xenobiotic metabolism/degradation is discussed.

  11. 40 CFR 721.450 - Hydrofluorochloroalkene (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....450 Section 721.450 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.450 Hydrofluorochloroalkene (generic). (a) Chemical substance and significant new uses...

  12. 48 CFR 235.001 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.001 Definitions. “Research and development” means those efforts described by the Research, Development, Test, and Evaluation...

  13. Inactivation of the hepatic cytochrome P450 system by conditional deletion of hepatic cytochrome P450 reductase.

    PubMed

    Henderson, Colin J; Otto, Diana M E; Carrie, Dianne; Magnuson, Mark A; McLaren, Aileen W; Rosewell, Ian; Wolf, C Roland

    2003-04-11

    Cytochrome P450 (CYP) monooxygenases catalyze the oxidation of a large number of endogenous compounds and the majority of ingested environmental chemicals, leading to their elimination and often to their metabolic activation to toxic products. This enzyme system therefore provides our primary defense against xenobiotics and is a major determinant in the therapeutic efficacy of pharmacological agents. To evaluate the importance of hepatic P450s in normal homeostasis, drug pharmacology, and chemical toxicity, we have conditionally deleted the essential electron transfer protein, NADH:ferrihemoprotein reductase (EC, cytochrome P450 reductase, CPR) in the liver, resulting in essentially complete ablation of hepatic microsomal P450 activity. Hepatic CPR-null mice could no longer break down cholesterol because of their inability to produce bile acids, and whereas hepatic lipid levels were significantly increased, circulating levels of cholesterol and triglycerides were severely reduced. Loss of hepatic P450 activity resulted in a 5-fold increase in P450 protein, indicating the existence of a negative feedback pathway regulating P450 expression. Profound changes in the in vivo metabolism of pentobarbital and acetaminophen indicated that extrahepatic metabolism does not play a major role in the disposition of these compounds. Hepatic CPR-null mice developed normally and were able to breed, indicating that hepatic microsomal P450-mediated steroid hormone metabolism is not essential for fertility, demonstrating that a major evolutionary role for hepatic P450s is to protect mammals from their environment.

  14. 48 CFR 235.070-1 - Indemnification under research and development contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... research and development contracts. 235.070-1 Section 235.070-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING RESEARCH AND DEVELOPMENT CONTRACTING 235.070-1 Indemnification under research and development contracts. (a...

  15. 47 CFR 10.450 - Geographic targeting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Geographic targeting. 10.450 Section 10.450 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL MOBILE ALERT SYSTEM Alert Message Requirements § 10.450 Geographic targeting. This section establishes minimum requirements for the geographic...

  16. Characterization of corrosion phenomena and kinetics on T91 ferritic/martensitic steel exposed at 450 and 550 °C to flowing Pb-Bi eutectic with 10-7 mass% dissolved oxygen

    NASA Astrophysics Data System (ADS)

    Tsisar, Valentyn; Schroer, Carsten; Wedemeyer, Olaf; Skrypnik, Aleksandr; Konys, Jürgen

    2017-10-01

    Corrosion behavior of two heats of T91 ferritic/martensitic steel, with slightly different Cr content, was investigated in flowing (2 m/s) Pb-Bi with 10-7 mass%O at 450 and 550 °C. The observed corrosion modes are: protective scale formation; accelerated oxidation and solution-based corrosion attack. Accelerated oxidation at 450 °C results in general metal recession of about 10 μm after ∼9000 h exposure and ∼15 μm at 550 °C after 2000 h. More severe and local solution-based corrosion results in a maximum depth of attack of 50-960 μm and 115-190 μm, correspondingly. Incubation period for solution-based corrosion is 500-5000 h at 450 °C and ≤500 h at 550 °C. The slightly higher chromium content in one of the heat of T91 steel prolongs the incubation period by improving the stability of the Cr-based oxide film.

  17. Whole genome co-expression analysis of soybean cytochrome P450 genes identifies nodulation-specific P450 monooxygenases

    PubMed Central

    2010-01-01

    Background Cytochrome P450 monooxygenases (P450s) catalyze oxidation of various substrates using oxygen and NAD(P)H. Plant P450s are involved in the biosynthesis of primary and secondary metabolites performing diverse biological functions. The recent availability of the soybean genome sequence allows us to identify and analyze soybean putative P450s at a genome scale. Co-expression analysis using an available soybean microarray and Illumina sequencing data provides clues for functional annotation of these enzymes. This approach is based on the assumption that genes that have similar expression patterns across a set of conditions may have a functional relationship. Results We have identified a total number of 332 full-length P450 genes and 378 pseudogenes from the soybean genome. From the full-length sequences, 195 genes belong to A-type, which could be further divided into 20 families. The remaining 137 genes belong to non-A type P450s and are classified into 28 families. A total of 178 probe sets were found to correspond to P450 genes on the Affymetrix soybean array. Out of these probe sets, 108 represented single genes. Using the 28 publicly available microarray libraries that contain organ-specific information, some tissue-specific P450s were identified. Similarly, stress responsive soybean P450s were retrieved from 99 microarray soybean libraries. We also utilized Illumina transcriptome sequencing technology to analyze the expressions of all 332 soybean P450 genes. This dataset contains total RNAs isolated from nodules, roots, root tips, leaves, flowers, green pods, apical meristem, mock-inoculated and Bradyrhizobium japonicum-infected root hair cells. The tissue-specific expression patterns of these P450 genes were analyzed and the expression of a representative set of genes were confirmed by qRT-PCR. We performed the co-expression analysis on many of the 108 P450 genes on the Affymetrix arrays. First we confirmed that CYP93C5 (an isoflavone synthase gene) is

  18. 33 CFR 162.235 - Puget Sound Area, Wash.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Puget Sound Area, Wash. 162.235...) PORTS AND WATERWAYS SAFETY INLAND WATERWAYS NAVIGATION REGULATIONS § 162.235 Puget Sound Area, Wash. (a.... Southbound boats shall sound the signal within 600 yards of Port Townsend Canal Light. Northbound boats shall...

  19. Evaluation of naturally occurring radioactivity across the State of Kuwait using high-resolution gamma-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Bajoga, A. D.; Alazemi, N.; Shams, H.; Regan, P. H.; Bradley, D. A.

    2017-08-01

    A study of natural radioactivity from 90 different soil samples from the state of Kuwait has been carried out to ascertain the NORM concentration values across the country. The calculated activity concentrations were determined from: (i) the decays of the 226Ra, 214Pb and 214Bi members of the 4n+2 decay chain headed by 238U and; (ii) the 228Ac, 212Pb and 208Tl members of the 4n chain headed by 232Th. The study also included evaluations for the 235U decay chain with the 186 keV doublet transition used together with the measured 4n+2 activity concentration values to determine the 235U/238U isotopic ratios for each sample. The values for the arithmetic mean activity concentrations for 90 separate locations across Kuwait as determined in the current work were 17.2, 14.1, and 368 Bq/kg, with standard deviations of 5.2, 3.7 and 90 Bq/kg for the 238U, 232Th and 40K activity concentrations respectively. Measured isotope ratios for 235U/238U give an arithmetic mean value for all of the samples of 0.045±0.003, consistent with that expected for natural uranium. These results indicate no evidence for a radiologically significant dispersion of additional depleted uranium across the entire State of Kuwait from the 1991 Gulf War.

  20. Carotid dual-energy CT angiography: Evaluation of low keV calculated monoenergetic datasets by means of a frequency-split approach for noise reduction at low keV levels.

    PubMed

    Riffel, Philipp; Haubenreisser, Holger; Meyer, Mathias; Sudarski, Sonja; Morelli, John N; Schmidt, Bernhard; Schoenberg, Stefan O; Henzler, Thomas

    2016-04-01

    Calculated monoenergetic ultra-low keV datasets did not lead to improved contrast-to-noise ratio (CNR) due to the dramatic increase in image noise. The aim of the present study was to evaluate the objective image quality of ultra-low keV monoenergetic images (MEIs) calculated from carotid DECT angiography data with a new monoenergetic imaging algorithm using a frequency-split technique. 20 patients (12 male; mean age 53±17 years) were retrospectively analyzed. MEIs from 40 to 120 keV were reconstructed using the monoenergetic split frequency approach (MFSA). Additionally MEIs were reconstructed for 40 and 50 keV using a conventional monoenergetic (CM) software application. Signal intensity, noise, signal-to-noise ratio (SNR) and CNR were assessed in the basilar, common, internal carotid arteries. Ultra-low keV MEIs at 40 keV and 50 keV demonstrated highest vessel attenuation, significantly greater than those of the polyenergetic images (PEI) (all p-values <0.05). The highest SNR level and CNR level was found at 40 keV and 50 keV (all p-values <0.05). MEIs with MFSA showed significantly lower noise levels than those processed with CM (all p-values <0.05) and no significant differences in vessel attenuation (p>0.05). Thus MEIs with MFSA showed significantly higher SNR and CNR compared to MEIs with CM. Combining the lower spatial frequency stack for contrast at low keV levels with the high spatial frequency stack for noise at high keV levels (frequency-split technique) leads to improved image quality of ultra-low keV monoenergetic DECT datasets when compared to previous monoenergetic reconstruction techniques without the frequency-split technique. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. 46 CFR 130.450 - Machinery alarms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Machinery alarms. 130.450 Section 130.450 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS VESSEL CONTROL, AND MISCELLANEOUS EQUIPMENT AND SYSTEMS Automation of Unattended Machinery Spaces § 130.450 Machinery alarms. (a...

  2. Cross section for the subthreshold fission of 236U

    NASA Astrophysics Data System (ADS)

    Alekseev, A. A.; Bergman, A. A.; Berlev, A. I.; Koptelov, E. A.; Samylin, B. F.; Trufanov, A. M.; Fursov, B. I.; Shorin, V. S.

    2008-08-01

    The cross section for 236U fission in the neutron-energy range E n = 0.001 20 keV was measured by using the INR RAS (Institute of Nuclear Research, Russian Academy of Sciences, Moscow) LSDS-100 neutron spectrometer of the lead slowing-down spectrometer type. The resonance fission areas of the resonances at 5.45 eV and 1.28 keV were found, and the fission widths of these resonances were evaluated. The cross section for the 238U( n, f) fission process was measured, and the threshold sensitivity of the LSDS-100 to small values of fission cross sections was estimated. The well-known intermediate structure in the cross section for the neutron-induced subbarrier fission of 236U was confirmed.

  3. Green Power Partnership Fortune 500® Partners List

    EPA Pesticide Factsheets

    U.S. EPA's Green Power Partnership is a voluntary program designed to reduce the environmental impact of electricity generation by promoting renewable energy. This Top Partner list presents Green Power Partners that also appear on the Fortune 500® list.

  4. Reexamining the role of the ( n , γ f ) process in the low-energy fission of U 235 and Pu 239

    DOE PAGES

    Lynn, J. E.; Talou, P.; Bouland, O.

    2018-06-01

    In this paper, themore » $$(n,{\\gamma}f)$$ process is reviewed in light of modern nuclear reaction calculations in both slow and fast neutron-induced fission reactions on $$^{235}\\mathrm{U}$$ and $$^{239}\\mathrm{Pu}$$. Observed fluctuations of the average prompt fission neutron multiplicity and average total $${\\gamma}$$-ray energy below 100-eV incident neutron energy are interpreted in this framework. The surprisingly large contribution of the $M1$ transitions to the prefission $${\\gamma}$$-ray spectrum of $$^{239}\\mathrm{Pu}$$ is explained by the dominant fission probabilities of $${0}^{+}$$ and $${2}^{+}$$ transition states, which can only be accessed from compound nucleus states formed by the interaction of $s$-wave neutrons with the target nucleus in its ground state, and decaying through $M1$ transitions. The impact of an additional low-lying $M1$ scissors mode in the photon strength function is analyzed. We review experimental evidence for fission fragment mass and kinetic-energy fluctuations in the resonance region and their importance in the interpretation of experimental data on prompt neutron data in this region. In conclusion, calculations are extended to the fast energy range where $$(n,{\\gamma}f)$$ corrections can account for up to 3% of the total fission cross section and about 20% of the capture cross section.« less

  5. Reexamining the role of the (n ,γ f ) process in the low-energy fission of 235U and 239Pu

    NASA Astrophysics Data System (ADS)

    Lynn, J. E.; Talou, P.; Bouland, O.

    2018-06-01

    The (n ,γ f ) process is reviewed in light of modern nuclear reaction calculations in both slow and fast neutron-induced fission reactions on 235U and 239Pu. Observed fluctuations of the average prompt fission neutron multiplicity and average total γ -ray energy below 100-eV incident neutron energy are interpreted in this framework. The surprisingly large contribution of the M 1 transitions to the prefission γ -ray spectrum of 239Pu is explained by the dominant fission probabilities of 0+ and 2+ transition states, which can only be accessed from compound nucleus states formed by the interaction of s -wave neutrons with the target nucleus in its ground state, and decaying through M 1 transitions. The impact of an additional low-lying M 1 scissors mode in the photon strength function is analyzed. We review experimental evidence for fission fragment mass and kinetic-energy fluctuations in the resonance region and their importance in the interpretation of experimental data on prompt neutron data in this region. Finally, calculations are extended to the fast energy range where (n ,γ f ) corrections can account for up to 3% of the total fission cross section and about 20% of the capture cross section.

  6. Reexamining the role of the ( n , γ f ) process in the low-energy fission of U 235 and Pu 239

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lynn, J. E.; Talou, P.; Bouland, O.

    In this paper, themore » $$(n,{\\gamma}f)$$ process is reviewed in light of modern nuclear reaction calculations in both slow and fast neutron-induced fission reactions on $$^{235}\\mathrm{U}$$ and $$^{239}\\mathrm{Pu}$$. Observed fluctuations of the average prompt fission neutron multiplicity and average total $${\\gamma}$$-ray energy below 100-eV incident neutron energy are interpreted in this framework. The surprisingly large contribution of the $M1$ transitions to the prefission $${\\gamma}$$-ray spectrum of $$^{239}\\mathrm{Pu}$$ is explained by the dominant fission probabilities of $${0}^{+}$$ and $${2}^{+}$$ transition states, which can only be accessed from compound nucleus states formed by the interaction of $s$-wave neutrons with the target nucleus in its ground state, and decaying through $M1$ transitions. The impact of an additional low-lying $M1$ scissors mode in the photon strength function is analyzed. We review experimental evidence for fission fragment mass and kinetic-energy fluctuations in the resonance region and their importance in the interpretation of experimental data on prompt neutron data in this region. In conclusion, calculations are extended to the fast energy range where $$(n,{\\gamma}f)$$ corrections can account for up to 3% of the total fission cross section and about 20% of the capture cross section.« less

  7. 40 CFR 450.11 - General definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false General definitions. 450.11 Section 450.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CONSTRUCTION AND DEVELOPMENT POINT SOURCE CATEGORY General Provisions § 450.11 General definitions. (a) New source. New source means any...

  8. 46 CFR 130.450 - Machinery alarms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Machinery alarms. 130.450 Section 130.450 Shipping COAST... MISCELLANEOUS EQUIPMENT AND SYSTEMS Automation of Unattended Machinery Spaces § 130.450 Machinery alarms. (a... must provide battery power for the alarm required by § 130.460(a)(8) of this subpart. ...

  9. 46 CFR 130.450 - Machinery alarms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Machinery alarms. 130.450 Section 130.450 Shipping COAST... MISCELLANEOUS EQUIPMENT AND SYSTEMS Automation of Unattended Machinery Spaces § 130.450 Machinery alarms. (a... must provide battery power for the alarm required by § 130.460(a)(8) of this subpart. ...

  10. 46 CFR 130.450 - Machinery alarms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Machinery alarms. 130.450 Section 130.450 Shipping COAST... MISCELLANEOUS EQUIPMENT AND SYSTEMS Automation of Unattended Machinery Spaces § 130.450 Machinery alarms. (a... must provide battery power for the alarm required by § 130.460(a)(8) of this subpart. ...

  11. 46 CFR 130.450 - Machinery alarms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Machinery alarms. 130.450 Section 130.450 Shipping COAST... MISCELLANEOUS EQUIPMENT AND SYSTEMS Automation of Unattended Machinery Spaces § 130.450 Machinery alarms. (a... must provide battery power for the alarm required by § 130.460(a)(8) of this subpart. ...

  12. Comparison of Grab, Air, and Surface Results for Radiation Site Characterization

    NASA Astrophysics Data System (ADS)

    Glassford, Eric Keith

    2011-12-01

    The use of proper sampling methods and sample types for evaluating sites believed to be contaminated with radioactive materials is necessary to avoid misrepresenting conditions at the site. This study was designed to investigate if the site characterization, based upon uranium contamination measured in different types of samples, is dependent upon the mass of the sample collected. A bulk sample of potentially contaminated interior dirt was collected from an abandoned metal processing mill that rolled uranium between 1948 and 1956. The original mill dates from 1910 and has a dirt floor. The bulk sample was a mixture of dirt, black and yellow particles of metal dust, and small fragments of natural debris. Small mass (approximately 0.75 grams (g)) and large mass (approximately 70g) grab samples were prepared from the bulk sample material to simulate collection of a "grab" type sample. Air sampling was performed by re-suspending a portion of the bulk sample material using a vibration table to simulate airborne contamination that might be present during site remediation. Additionally, samples of removable contaminated surface dust were collected on 47 mm diameter filter paper by wiping the surfaces of the exposure chamber used to resuspend the bulk material. Certified reference materials, one containing a precisely known quantity of U 3O8 and one containing a known quantity of natural uranium, were utilized to calibrate the gamma spectrometry measurement system. Non-destructive gamma spectrometry measurements were used to determine the content of uranium-235 (235U) at 185 keV and 143 keV, thorium-234 (234Th) at 63 keV, and protactinium-234m (234mPa) at 1001 keV in each sample. Measurement of natural uranium in small, 1 g samples is usually accomplished by radiochemical analysis in order to measure alpha particles emitted by 238U, 235U, and 234U. However, uranium in larger bulk samples can also be measured non-destructively using gamma spectrometry to detect the low

  13. The cytochrome p450 homepage.

    PubMed

    Nelson, David R

    2009-10-01

    The Cytochrome P450 Homepage is a universal resource for nomenclature and sequence information on cytochrome P450 ( CYP ) genes. The site has been in continuous operation since February 1995. Currently, naming information for 11,512 CYPs are available on the web pages. The P450 sequences are manually curated by David Nelson, and the nomenclature system conforms to an evolutionary scheme such that members of CYP families and subfamilies share common ancestors. The organisation and content of the Homepage are described.

  14. 20 CFR 627.450 - Program income.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Program income. 627.450 Section 627.450... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Administrative Standards § 627.450 Program income. (a) Definition of program income. (1) Program income means income received by the recipient or subrecipient that...

  15. Cytochrome P450s and molecular epidemiology

    NASA Astrophysics Data System (ADS)

    Gonzalez, Frank J.; Gelboin, Harry V.

    1993-03-01

    Cytochrome P450 (P450) represent a superfamily of heme-containing monooxygenases that are found throughout the animal and plant kingdoms and in many microorganisms. A number of these enzymes are involved in biosynthetic pathways of steroid synthesis but in mammals the vast majority of P450s function to metabolize foreign chemicals or xenobiotics. In the classical phase I reactions on the latter, a membrane-bound P450 will hydroxylate a compound, usually hydrophobic in nature, and the hydroxyl group will serve as a substrate for the various transferases or phase II enzymes that attach hydrophilic substituents such as glutathione, sulfate or glucuronic acid. Some chemicals, however, are metabolically-activated by P450s to electrophiles capable of reacting with cellular macromolecules. The cellular concentrations of the chemical and P450, reactivity of the active metabolite with nucleic acid and the repairability of the resultant adducts, in addition to the nature of the cell type, likely determines whether a chemical will be toxic and kill the cell or will transform the cell. Immunocorrelative and cDNA-directed expression have been used to define the substrate specificities of numerous human P450s. Levels of expression of different human P450 forms have been measured by both in vivo and in vitro methodologies leading to the realization that a large degree of interindividual differences occur in P450 expression. Reliable procedures for measuring P450 expression in healthy and diseased subjects will lead to prospective and case- cohort studies to determine whether interindividual differences in levels of P450 are associated with susceptibility or resistance to environmentally-based disease.

  16. 40 CFR 415.235 - New source performance standards (NSPS).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true New source performance standards (NSPS). 415.235 Section 415.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Aluminum Fluoride Production...

  17. 40 CFR 415.235 - New source performance standards (NSPS).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true New source performance standards (NSPS). 415.235 Section 415.235 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Aluminum Fluoride Production...

  18. 7 CFR 981.450 - Exempt dispositions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Exempt dispositions. 981.450 Section 981.450... Administrative Rules and Regulations § 981.450 Exempt dispositions. As provided in § 981.50 any handler disposing of almonds for crushing into oil, or for poultry or animal feed, may have the kernel weight of these...

  19. The Cytochrome P450 Homepage

    PubMed Central

    2009-01-01

    The Cytochrome P450 Homepage is a universal resource for nomenclature and sequence information on cytochrome P450 (CYP) genes. The site has been in continuous operation since February 1995. Currently, naming information for 11,512 CYPs are available on the web pages. The P450 sequences are manually curated by David Nelson, and the nomenclature system conforms to an evolutionary scheme such that members of CYP families and subfamilies share common ancestors. The organisation and content of the Homepage are described. PMID:19951895

  20. Influence of chlorine or fluorine substitution on the estrogenic properties of 1-alkyl-2,3,5-tris(4-hydroxyphenyl)-1H-pyrroles.

    PubMed

    Schäfer, Anja; Wellner, Anja; Strauss, Martin; Schäfer, Andreas; Wolber, Gerhard; Gust, Ronald

    2012-11-26

    In continuation of our previous work, several 1-alkyl-2,3,5-tris(4-hydroxyphenyl)aryl-1H-pyrroles with chlorine or fluorine substituents in the aryl residues were synthesized and tested for estrogen receptor (ER) binding at isolated ERα/ERβ receptors (HAP assay) and in transactivation assays using ERα-positive MCF-7/2a as well as U2-OS/ERα and U2-OS/ERβ cells. In the competition experiment at ERα the compounds displayed very high relative binding affinities of up to 37% (determined for 8m) but with restricted subtype selectivity (e.g., ERα/ERβ (8m) = 9). The highest estrogenic potency in ERα-positive MCF-7/2a cells was determined for 2,3,5-tris(2-fluoro-4-hydroxyphenyl)-1-propyl-1H-pyrrole 8m (EC(50) = 23 nM), while in U2-OS/ERα cells 2-(2-fluoro-4-hydroxyphenyl)-3,5-bis(4-hydroxyphenyl)-1-propyl-1H-pyrrole 8b (EC(50) = 0.12 nM) was the most potent agonist, only 30-fold less active than estradiol (E2, EC(50) = 0.004 nM). In U2-OS/ERβ cells for all pyrroles no transactivation could be observed, which indicates that they are selective ERα agonists in cellular systems.