The crystal structure of ianthinite, [U24+(UO2)4O6(OH)4(H2O)4](H2O)5: a possible phase for Pu4+ incorporation during the oxidation of spent nuclear fuel

International Nuclear Information System (INIS)

Burns, P.C.; Hawthorne, F.C.; Miller, M.L.; Ewing, R.C.

1997-01-01

Ianthinite, [U 4+ 2 (UO 2 ) 4 O 6 (OH) 4 (H 2 O) 4 ](H 2O) 5 , is the only known uranyl oxide hydrate mineral that contains U 4+ , and it has been proposed that ianthinite may be an important Pu 4+ -bearing phase during the oxidative dissolution of spent nuclear fuel. The crystal structure of ianthinite, orthorhombic, a=0.7178(2), b=1.1473(2), c=3.039(1) nm, V=2.5027 nm 3 , Z=4, space group P2 1 cn, has been solved by direct methods and refined by least-squares methods to an R index of 9.7% and a wR index of 12.6% using 888 unique observed [ vertical stroke F vertical stroke ≥5σ vertical stroke F vertical stroke ] reflections. The structure contains both U 6+ and U 4+ . The U 6+ cations are present as roughly linear (U 6+ O 2 ) 2+ uranyl ions (Ur) that are in turn coordinated by five O 2- and OH - located at the equatorial positions of pentagonal bipyramids. The U 4+ cations are coordinated by O 2- , OH - and H 2 O in a distorted octahedral arrangement. The Urφ 5 and U 4+ φ 6 (φ: O 2- , OH - , H 2 O) polyhedra link by sharing edges to form two symmetrically distinct sheets at z∼0.0 and z∼0.25 that are parallel to (001). The sheets have the β-U 3 O 8 sheet anion-topology. There are five symmetrically distinct H 2 O groups located at z∼0.125 between the sheets of Uφ n polyhedra, and the sheets of Uφ n polyhedra are linked together only by hydrogen bonding to the intersheet H 2 O groups. The crystal-chemical requirements of U 4+ and Pu 4+ are very similar, suggesting that extensive Pu 4+ U 4+ substitution may occur within the sheets of Uφ n polyhedra in the structure of ianthinite. (orig.)

Assembly and dynamics of the U4/U6 di-snRNP by single-molecule FRET

Science.gov (United States)

Hardin, John W.; Warnasooriya, Chandani; Kondo, Yasushi; Nagai, Kiyoshi; Rueda, David

2015-01-01

In large ribonucleoprotein machines, such as ribosomes and spliceosomes, RNA functions as an assembly scaffold as well as a critical catalytic component. Protein binding to the RNA scaffold can induce structural changes, which in turn modulate subsequent binding of other components. The spliceosomal U4/U6 di-snRNP contains extensively base paired U4 and U6 snRNAs, Snu13, Prp31, Prp3 and Prp4, seven Sm and seven LSm proteins. We have studied successive binding of all protein components to the snRNA duplex during di-snRNP assembly by electrophoretic mobility shift assay and accompanying conformational changes in the U4/U6 RNA 3-way junction by single-molecule FRET. Stems I and II of the duplex were found to co-axially stack in free RNA and function as a rigid scaffold during the entire assembly, but the U4 snRNA 5′ stem-loop adopts alternative orientations each stabilized by Prp31 and Prp3/4 binding accounting for altered Prp3/4 binding affinities in presence of Prp31. PMID:26503251

Single crystal structures and theoretical calculations of uranium endohedral metallofullerenes (U@C2n , 2n = 74, 82) show cage isomer dependent oxidation states for U.

Science.gov (United States)

Cai, Wenting; Morales-Martínez, Roser; Zhang, Xingxing; Najera, Daniel; Romero, Elkin L; Metta-Magaña, Alejandro; Rodríguez-Fortea, Antonio; Fortier, Skye; Chen, Ning; Poblet, Josep M; Echegoyen, Luis

2017-08-01

Charge transfer is a general phenomenon observed for all endohedral mono-metallofullerenes. Since the detection of the first endohedral metallofullerene (EMF), La@C 82 , in 1991, it has always been observed that the oxidation state of a given encapsulated metal is always the same, regardless of the cage size. No crystallographic data exist for any early actinide endohedrals and little is known about the oxidation states for the few compounds that have been reported. Here we report the X-ray structures of three uranium metallofullerenes, U@ D 3h -C 74 , U@ C 2 (5)-C 82 and U@ C 2v (9)-C 82 , and provide theoretical evidence for cage isomer dependent charge transfer states for U. Results from DFT calculations show that U@ D 3h -C 74 and U@ C 2 (5)-C 82 have tetravalent electronic configurations corresponding to U 4+ @ D 3h -C 74 4- and U 4+ @ C 2 (5)-C 82 4- . Surprisingly, the isomeric U@ C 2v (9)-C 82 has a trivalent electronic configuration corresponding to U 3+ @ C 2v (9)-C 82 3- . These are the first X-ray crystallographic structures of uranium EMFs and this is first observation of metal oxidation state dependence on carbon cage isomerism for mono-EMFs.

The [U{sub 2}F{sub 12}]{sup 2-} anion of Sr[U{sub 2}F{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Scheibe, Benjamin; Pietzonka, Clemens; Conrad, Matthias; Kraus, Florian [Fachbereich Chemie, Philipps-Universitaet Marburg (Germany); Mustonen, Otto; Karppinen, Maarit; Karttunen, Antti J. [Department of Chemistry, Aalto University (Finland); Atanasov, Mihail; Neese, Frank [Max-Planck Institute for Chemical Energy Conversion, Muelheim an der Ruhr (Germany)

2018-03-05

The D{sub 2h}-symmetric dinuclear complex anion [U{sub 2}F{sub 12}]{sup 2-} of pastel green Sr[U{sub 2}F{sub 12}] shows a hitherto unknown structural feature: The coordination polyhedra around the U atoms are edge-linked monocapped trigonal prisms, the U{sup V} atoms are therefore seven-coordinated. This leads to a U-U distance of 3.8913(6) Aa. A weak U{sup V}-U{sup V} interaction is observed for the dinuclear [U{sub 2}F{sub 12}]{sup 2-} complex and described by the antiferromagnetic exchange J{sub exp} of circa -29.9 cm{sup -1}. The crystalline compound can be easily prepared from SrF{sub 2} and β-UF{sub 5} in anhydrous hydrogen fluoride (aHF) at room temperature. It was studied by means of single crystal X-ray diffraction, IR, Raman and UV/VIS spectroscopy, magnetic measurements, and by molecular as well as by solid-state quantum chemical calculations. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Probable superbursts in 4U 0614+091 and 4U 1608-522

Science.gov (United States)

Kuulkers, E.

2005-05-01

Inspection of the RXTE/ASM database of 4U 0614+091 reveals a recent flare which occurred on March 12, 2005. The 1.5-12 keV flux increased by a factor of 5-6 up to 0.3 Crab within ~7.5 hours. About 1.5 hours later the flux had dropped to 0.17 Crab; ~9.5 hours later it had reached the pre-flare flux level again. The exponential decay time of the flare is about 2.2 hours. During the peak of the flare the X-ray emission significantly hardens with respect to the pre- and post-flare level.

Exploring a new S U (4 ) symmetry of meson interpolators

Science.gov (United States)

Glozman, L. Ya.; Pak, M.

2015-07-01

In recent lattice calculations it has been discovered that mesons upon truncation of the quasizero modes of the Dirac operator obey a symmetry larger than the S U (2 )L×S U (2 )R×U (1 )A symmetry of the QCD Lagrangian. This symmetry has been suggested to be S U (4 )⊃S U (2 )L×S U (2 )R×U (1 )A that mixes not only the u- and d-quarks of a given chirality, but also the left- and right-handed components. Here it is demonstrated that bilinear q ¯q interpolating fields of a given spin J ≥1 transform into each other according to irreducible representations of S U (4 ) or, in general, S U (2 NF). This fact together with the coincidence of the correlation functions establishes S U (4 ) as a symmetry of the J ≥1 mesons upon quasizero mode reduction. It is shown that this symmetry is a symmetry of the confining instantaneous charge-charge interaction in QCD. Different subgroups of S U (4 ) as well as the S U (4 ) algebra are explored.

Intake of 210Po, 234U and 238U radionuclides with beer in Poland

International Nuclear Information System (INIS)

Skwarzec, B.; Struminska, D.I.; Borylo, A.; Falandysz, J.

2004-01-01

238 U, 234 U and 210 Po activity concentrations were determined in beer in Poland by alpha-spectrometry with low-level activity silicon detectors. The results revealed that the mean concentrations of 238 U, 234 U and 210 Po in the analyzed beer samples were 4.63, 4.11 and 4.94 mBq x dm -3 , respectively, the highest in Tyskie (5.71 for 210 Po, 5.06 for 234 U and 6.11 for 238 U) and the lowest in Lech (2.49 for 210 Po). The effective radiation dose due to uranium and polonium ingestions by beer was calculated and were compared to the effective radiation dose from drinking water. (author)

U enrichment and Th/U fractionation in Archean boninites: Implications for paleo-ocean oxygenation and U cycling at juvenile subduction zones

Science.gov (United States)

Manikyamba, C.; Said, Nuru; Santosh, M.; Saha, Abhishek; Ganguly, Sohini; Subramanyam, K. S. V.

2018-05-01

Phanerozoic boninites record enrichments of U over Th, giving Th/U: 0.5-1.6, relative to intraoceanic island arc tholeiites (IAT) where Th/U averages 2.6. Uranium enrichment is attributed to incorporation of shallow, oxidized fluids, U-rich but Th-poor, from the slab into the melt column of boninites which form in near-trench to forearc settings of suprasubduction zone ophiolites. Well preserved Archean komatiite-tholeiite, plume-derived, oceanic volcanic sequences have primary magmatic Th/U ratios of 4.4-3.6, and Archean convergent margin IAT volcanic sequences, having REE and HFSE compositions similar to Phanerozoic IAT equivalents, preserve primary Th/U of 4-3.6. The best preserved Archean boninites of the 3.0 Ga Olondo and 2.7 Ga Gadwal greenstone belts, hosted in convergent margin ophiolite sequences, also show relative enrichments of U over Th, with low average Th/U ∼3 relative to coeval IAT, and Phanerozoic counterparts which are devoid of crustal contamination and therefore erupted in an intraoceanic setting, with minimal contemporaneous submarine hydrothermal alteration. Later enrichment of U is unlikely as Th-U-Nb-LREE patterns are coherent in these boninites whereas secondary effects induce dispersion of Th/U ratios. The variation in Th/U ratios from Archean to Phanerozoic boninites of greenstone belts to ophiolitic sequences reflect on genesis of boninitic lavas at different tectono-thermal regimes. Consequently, if the explanation for U enrichment in Phanerozoic boninites also applies to Archean examples, the implication is that U was soluble in oxygenated Archean marine water up to 600 Ma before the proposed great oxygenation event (GOE) at ∼2.4 Ga. This interpretation is consistent with large Ce anomalies in some hydrothermally altered Archean volcanic sequences aged 3.0-2.7 Ga.

Path integral for coherent states of the dynamical U2 group and U2/1 supergroup

International Nuclear Information System (INIS)

Kochetov, E.A.

1992-01-01

A part-integral formulation in the representation of coherent states for the unitary U 2 group and U 2/1 supergroup is introduced. U 2 and U 2/1 path integrals are shown to be defined on the coset spaces U 2 /U 1 xU 1 and U 2/1 /U 1/1 xU 1 , respectively. These coset appears as curved classical phase spaces. Partition functions are expressed as path integrals over these spaces. In the case when U 2 and U 2/1 are the dynamical groups, the corresponding path integrals are evaluated with the help of linear fractional transformations that appear as the group (supergroup) action in the coset space (superspace). Possible applications for quantum models are discussed. 9 refs

Theoretical modeling of the uranium 4f XPS for U(VI) and U(IV) oxides

Energy Technology Data Exchange (ETDEWEB)

Bagus, Paul S. [Department of Chemistry, University of North Texas, Denton, Texas 76203-5017 (United States); Nelin, Connie J. [Consulting and Services, 6008 Maury' s Trail, Austin, Texas 78730 (United States); Ilton, Eugene S. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2013-12-28

A rigorous study is presented of the physical processes related to X-Ray photoelectron spectroscopy, XPS, in the 4f level of U oxides, which, as well as being of physical interest in themselves, are representative of XPS in heavy metal oxides. In particular, we present compelling evidence for a new view of the screening of core-holes that extends prior understandings. Our analysis of the screening focuses on the covalent mixing of high lying U and O orbitals as opposed to the, more common, use of orbitals that are nominally pure U or pure O. It is shown that this covalent mixing is quite different for the initial and final, core-hole, configurations and that this difference is directly related to the XPS satellite intensity. Furthermore, we show that the high-lying U d orbitals as well as the U(5f) orbital may both contribute to the core-hole screening, in contrast with previous work that has only considered screening through the U(5f) shell. The role of modifying the U-O interaction by changing the U-O distance has been investigated and an unexpected correlation between U-O distance and XPS satellite intensity has been discovered. The role of flourite and octahedral crystal structures for U(IV) oxides has been examined and relationships established between XPS features and the covalent interactions in the different structures. The physical views of XPS satellites as arising from shake processes or as arising from ligand to metal charge transfers are contrasted; our analysis provides strong support that shake processes give a more fundamental physical understanding than charge transfer. Our theoretical studies are based on rigorous, strictly ab initio determinations of the electronic structure of embedded cluster models of U oxides with formal U(VI) and U(IV) oxidation states. Our results provide a foundation that makes it possible to establish quantitative relationships between features of the XPS spectra and materials properties.

Theoretical modeling of the uranium 4f XPS for U(VI) and U(IV) oxides

Science.gov (United States)

Bagus, Paul S.; Nelin, Connie J.; Ilton, Eugene S.

2013-12-01

A rigorous study is presented of the physical processes related to X-Ray photoelectron spectroscopy, XPS, in the 4f level of U oxides, which, as well as being of physical interest in themselves, are representative of XPS in heavy metal oxides. In particular, we present compelling evidence for a new view of the screening of core-holes that extends prior understandings. Our analysis of the screening focuses on the covalent mixing of high lying U and O orbitals as opposed to the, more common, use of orbitals that are nominally pure U or pure O. It is shown that this covalent mixing is quite different for the initial and final, core-hole, configurations and that this difference is directly related to the XPS satellite intensity. Furthermore, we show that the high-lying U d orbitals as well as the U(5f) orbital may both contribute to the core-hole screening, in contrast with previous work that has only considered screening through the U(5f) shell. The role of modifying the U-O interaction by changing the U-O distance has been investigated and an unexpected correlation between U-O distance and XPS satellite intensity has been discovered. The role of flourite and octahedral crystal structures for U(IV) oxides has been examined and relationships established between XPS features and the covalent interactions in the different structures. The physical views of XPS satellites as arising from shake processes or as arising from ligand to metal charge transfers are contrasted; our analysis provides strong support that shake processes give a more fundamental physical understanding than charge transfer. Our theoretical studies are based on rigorous, strictly ab initio determinations of the electronic structure of embedded cluster models of U oxides with formal U(VI) and U(IV) oxidation states. Our results provide a foundation that makes it possible to establish quantitative relationships between features of the XPS spectra and materials properties.

Photoassociation spectroscopy of 87Rb2 (5s1/2+5p1/2)0u+ long-range molecular states: Coupling with the (5s1/2+5p3/2)0u+ series analyzed using the Lu-Fano approach

International Nuclear Information System (INIS)

Jelassi, H.; Viaris de Lesegno, B.; Pruvost, L.

2006-01-01

We report on photoassociation of cold 87 Rb atoms providing the spectroscopy of (5s 1/2 +5p 1/2 )0 u + long-range molecular states, in the energy range of [-12.5, -0.7 cm -1 ] below the dissociation limit. A Lu-Fano approach coupled to the LeRoy-Bernstein formula is used to analyze the data. The Lu-Fano graph exhibits the coupling of the molecular series with the (5s 1/2 +5p 3/2 )0 u + one, which is due to spin effects in the molecule. A two-channel model involving an improved LeRoy-Bernstein formula allows us to characterize the molecular series, to localize (5s 1/2 +5p 3/2 )0 u + levels, to evaluate the coupling, and to predict the energy and width of the first predissociated level of (5s 1/2 +5p 3/2 )0 u + series. An experimental spectrum confirms the prediction

Accurate 238U(n , 2 n )237U reaction cross-section measurements from 6.5 to 14.8 MeV

Science.gov (United States)

Krishichayan, Bhike, M.; Tornow, W.; Tonchev, A. P.; Kawano, T.

2017-10-01

The cross section for the 238U(n ,2 n )237U reaction has been measured in the incident neutron energy range from 6.5 to 14.8 MeV in small energy steps using an activation technique. Monoenergetic neutron beams were produced via the 2H(d ,n )3He and 3H(d ,n )4He reactions. 238U targets were activated along with Au and Al monitor foils to determine the incident neutron flux. The activity of the reaction products was measured in TUNL's low-background counting facility using high-resolution γ -ray spectroscopy. The results are compared with previous measurements and latest data evaluations. Statistical-model calculations, based on the Hauser-Feshbach formalism, have been carried out using the CoH3 code and are compared with the experimental results. The present self-consistent and high-quality data are important for stockpile stewardship and nuclear forensic purposes as well as for the design and operation of fast reactors.

Nu2U

DEFF Research Database (Denmark)

Sørensen, Hans Eibe; Williamson, Trevor

Abstract In September 2014, nine months after launching a major growth opportunity, Jenny Dunne, managing director of Nu2U, called for an extraordinary status meeting with her COO and CMO. A fast-growing online retailer of refurbished household appliances, Nu2U planned to acquire market share...... by improving internal logistics and delivery services, aided by a new, fully integrated software system. The company's gross profit had been increasing steadily, but recent accounts revealed a fall in net profit margins. It became apparent that implementation of the business plan for the project...... was problematic because of loose governance and poor communication across Nu2U's different specialist functions during planning and implementation. The Nu2U case illustrates how executives' cognition and span of control/overview may be hampered in fast-growing firms and how this ...

Crystal structures of Th(OH)PO4, U(OH)PO4 and Th2O(PO4)2. Condensation mechanism of M(IV)(OH)PO4 (M= Th, U) into M2O(PO4)2

International Nuclear Information System (INIS)

Dacheux, N.; Clavier, N.; Wallez, G.; Quarton, M.

2007-01-01

Three new crystal structures, isotypic with β-Zr 2 O(PO 4 ) 2 , have been resolved by the Rietveld method. All crystallize with an orthorhombic cell (S.G.: Cmca) with a = 7.1393(2) Angstroms, b = 9.2641(2) Angstroms, c 12.5262(4) Angstroms, V = 828.46(4) (Angstroms) 3 and Z = 8 for Th(OH)PO 4 ; a = 7.0100(2) Angstroms, b = 9.1200(2) Angstroms, c = 12.3665(3) Angstroms, V 790.60(4) (Angstroms) 3 and Z = 8 for U(OH)PO 4 ; a 7.1691(3) Angstroms, b 9.2388(4) Angstroms, c = 12.8204(7) Angstroms, V 849.15(7) (Angstroms) 3 and Z = 4 for Th 2 O(PO 4 ) 2 . By heating, the M(OH)PO 4 (M Th, U) compounds condense topotactically into M 2 O(PO 4 ) 2 , with a change of the environment of the tetravalent cation that lowers from 8 to 7 oxygen atoms. The lower stability of Th 2 O(PO 4 ) 2 compared to that of U 2 O(PO 4 ) 2 seems to result from this unusual environment for tetravalent thorium. (authors)

Electron loss from 1.4 MEV/u U4,6,10+ ions colliding with Ne, N2 and Ar targets

International Nuclear Information System (INIS)

DuBois, R.D.; Santos, A.C.F.; Stoehlker, T.

2004-07-01

Absolute, total, single, and multiple electron loss cross sections are measured for 1.4 MeV/u U 4,6,10+ ions colliding with neon and argon atoms and nitrogen molecules. It is found that the cross sections all have the same dependence on the number of electrons lost and that multiplying the cross sections by the initial number of electrons in the 6s, 6p, and 5f shells yields good agreement between the different projectiles. By combining the present data with previous measurements made at the same velocity, it is shown that the scaled cross sections slowly decrease in magnitude for incoming charge states between 1 and 10 whereas the cross sections for higher charge state ions fall off much more rapidly. (orig.)

U4+ spectroscopic properties in Dsub(2d) with ThCl4, UCl4 and ThSiO4

International Nuclear Information System (INIS)

Khan Malek, C.

1985-01-01

This thesis is concerned with the study of the electronic structure of the tetravalent actinide ions in solid state. The technique used was high resolution optical spectroscopy. We deal with the U 4+ ion (sf 2 ) in the monocrystals ThCl 4 , UCl 4 , and ThSiO 4 where the U 4+ ion is substituded for the Th 4+ ion by doping. Visible and infrared optical spectra were recorded between 300 and 4.2K. With these three compounds, it is possible to compare the influence of different environments of Dsub(2d) symmetry: real symmetry for U 4+ in UCl 4 and ThSiO 4 ; approximate symmetry in ThCl 4 , whose structure is incommensurate and modulated at low temperature. The fitting of the data was carried out by diagonalizing the hamiltonian which describes the interactions of the U 4+ ion in a crystal field with its environment. This fitting procedure led to a coherent set of spectroscopic parameters. The fluorescence of U 4+ was observed in ThCl 4 and ThSiO 4 and the effect of the incommensurate structure of ThCl 4 on the optical spectra was studied. The symmetry of the U 4+ sites was identified by site selective excitation experiments and a relationship between the incommensurate structure and the lifetime of U 4+ energy levels was found. In conclusion, the U 4+ energy levels in a relatively low crystal field were determined for compounds that have a similar coordination polyhedron about the actinide ion. The values for these energy levels were then compared to those of lanthanide and 3d elements [fr

Hydrogen absorption-desorption properties of U2Ti

International Nuclear Information System (INIS)

Yamamoto, Takuya; Tanaka, Satoru; Yamawaki, Michio

1990-01-01

Hydrogen absorption-desorption properties of U 2 Ti intermetallic compound was examined over the temperature range of 298 to 973 K and at hydrogen pressures below 10 5 Pa. It absorbs hydrogen up to 7.6 atoms per F.U. (formula unit) by two step reactions and hence each desorption isotherm is separated into two plateau regions. In the first plateau, a newly-found ternary hydride is formed, where the hydrogen concentration, c H , reaches 2.4 H atoms/F.U. In the second plateau, UH 3 is formed and c H reaches 7.6 H atoms/F.U. The specimen is disintegrated into fine powder in the second plateau, while in the first plateau the ternary hydride which was identified to be UTi 2 H x (x=4.8 to 6.2) showed high durability against powdering. It is predicted that UTi 2 can be suitable material for tritium storage. (orig.)

Neutronic Analysis of the RSG-GAS Compact Core without CIP Silicide 3.55 g U/cc and 4.8 g U/cc

International Nuclear Information System (INIS)

Jati S; Lily S; Tukiran S

2004-01-01

Fuel conversion from U 3 O 8 -Al to U 3 Si 2 -Al 2.96 g U/cc density in the RSG-GAS core had done successfully step by step since 36 th core until 44 th core. So that, since the 45 th core until now (48 th core) had been using full of silicide 2.96 g U/cc. Even though utilization program of silicide fuel with high density (3.55 g U/cc and 4.8 g U/cc) and optimize operation of RSG-GAS core under research. Optimalitation of core with increasing operation cycle have been analyzing about compact core. The mean of compact core is the RSG-GAS core with decrease number of IP or CIP position irradiation. In this research, the neutronic calculation to cover RSG-GAS core and RSG-GAS core without CIP that are using U 3 Si 2 -Al 2.96 g U/cc, 3.55 g U/cc and 4.8 g U/cc had done. Two core calculation done at 15 MW power using SRAC-ASMBURN code. The calculation result show that fuel conversion from 2.96 g U/cc density to 3.55 g U/cc and 4.8 g U/cc will increasing cycle length for both RSG-GAS core and RSG-GAS compact core without CIP. However, increasing of excess reactivity exceeded from nominal value of first design that 9.2%. Change of power peaking factor is not show significant value and still less than 1.4. Core fuelled with U 3 Si 2 -Al 4.8 g U/cc density have maximum discharge burn-up which exceeded from licensing value (70%). RSG-GAS compact core without CIP fuelled U 3 Si 2 -Al 2.96 g U/cc have longer cycle operation then RSG-GAS core and fulfil limitation neutronic parameter at the first design value. (author)

Measurement of 233U/234U ratios in contaminated groundwater using alpha spectrometry

International Nuclear Information System (INIS)

Harrison, Jennifer J.; Payne, Timothy E.; Wilsher, Kerry L.; Thiruvoth, Sangeeth; Child, David P.; Johansen, Mathew P.; Hotchkis, Michael A.C.

2016-01-01

The uranium isotope 233 U is not usually observed in alpha spectra from environmental samples due to its low natural and fallout abundance. It may be present in samples from sites in the vicinity of nuclear operations such as reactors or fuel reprocessing facilities, radioactive waste disposal sites or sites affected by clandestine nuclear operations. On an alpha spectrum, the two most abundant alpha emissions of 233 U (4.784 MeV, 13.2%; and 4.824 MeV, 84.3%) will overlap with the 234 U doublet peak (4.722 MeV, 28.4%; and 4.775 MeV, 71.4%), if present, resulting in a combined 233+234 U multiplet. A technique for quantifying both 233 U and 234 U from alpha spectra was investigated. A series of groundwater samples were measured both by accelerator mass spectrometry (AMS) to determine 233 U/ 234 U atom and activity ratios and by alpha spectrometry in order to establish a reliable 233 U estimation technique using alpha spectra. The Genie™ 2000 Alpha Analysis and Interactive Peak Fitting (IPF) software packages were used and it was found that IPF with identification of three peaks ( 234 U minor, combined 234 U major and 233 U minor, and 233 U major) followed by interference correction on the combined peak and a weighted average activity calculation gave satisfactory agreement with the AMS data across the 233 U/ 234 U activity ratio range (0.1–20) and 233 U activity range (2–300 mBq) investigated. Correlation between the AMS 233 U and alpha spectrometry 233 U was r 2  = 0.996 (n = 10). - Highlights: • Describes a technique for deconvoluting the combined 233 U and 234 U multiplet in alpha spectra. • Enables 233 U and 234 U activities and 233 U/ 234 U ratios to be quantified without requiring additional analysis and measurement. • Applicable to an environmental matrix (groundwater) using standard alpha spectrometry counting equipment, operation and set-up.

Milestone Report - Complete New Adsorbent Materials for Marine Testing to Demonstrate 4.5 g-U/kg Adsorbent

Energy Technology Data Exchange (ETDEWEB)

Janke, Christopher James [ORNL; Das, Sadananda [ORNL; Oyola, Yatsandra [ORNL; Mayes, Richard T. [ORNL; Saito, Tomonori [ORNL; Brown, Suree [ORNL; Gill, Gary [PNNL; Kuo, Li-Jung [PNNL; Wood, Jordana [PNNL

2014-08-01

This report describes work on the successful completion of Milestone M2FT-14OR03100115 (8/20/2014) entitled, “Complete new adsorbent materials for marine testing to demonstrate 4.5 g-U/kg adsorbent”. This effort is part of the Seawater Uranium Recovery Program, sponsored by the U.S. Department of Energy, Office of Nuclear Energy, and involved the development of new adsorbent materials at the Oak Ridge National Laboratory (ORNL) and marine testing at the Pacific Northwest National Laboratory (PNNL). ORNL has recently developed two new families of fiber adsorbents that have demonstrated uranium adsorption capacities greater than 4.5 g-U/kg adsorbent after marine testing at PNNL. One adsorbent was synthesized by radiation-induced graft polymerization of itaconic acid and acrylonitrile onto high surface area polyethylene fibers followed by amidoximation and base conditioning. This fiber showed a capacity of 4.6 g-U/kg adsorbent in marine testing at PNNL. The second adsorbent was prepared by atom-transfer radical polymerization of t-butyl acrylate and acrylonitrile onto halide-functionalized round fibers followed by amidoximation and base hydrolysis. This fiber demonstrated uranium adsorption capacity of 5.4 g-U/kg adsorbent in marine testing at PNNL.

Metallographic analysis of irradiated U3Si2/Al fuel element plate of 2.96 gU/cm3 density

International Nuclear Information System (INIS)

Maman Kartaman Ajiriyanto; Aslina Br Ginting; Junaedi

2018-01-01

Metallographic analysis of U 3 Si 2 /Al fuel element plate has been performed in hot cell. The purpose of metallographic analysis is to study changes in PEB U 3 Si 2 /Al microstructure and AlMg 2 cladding thickness after irradiation in reactor until burn up of 56 %. The fuel element plate of irradiated U 3 Si 2 /Al was cut in top, middle and bottom positions with each size around 5 x 5 x 1.37 mm. Metallographic preparation starts from sample cutting using cutting machine with low speed and sample mounting, grinding and polishing in hot cell 104–105. Sample mounting was done by using resin for more than 10 hours followed by grinding with sand papers up to grit size of 2400 and polishing with diamond paste of size 3 to 1 micron at a rotational speed of 150 rpm for 5 minutes. Microstructure observation was performed with optical microscope in hot cell 107 at 200 times magnification. Microstructure examination reveals U 3 Si 2 particles with inverse forms and sizes, Al matrix and AlMg 2 cladding were spread along the U 3 Si 2 /Al side. Microstructure observation of irradiated U 3 Si 2 /Al has not shown good result because only topography observation of U 3 Si 2 /Al meat, Al matrix and AlMg 2 cladding can be done due to limited capability of the optical microscope in hot cell, where maximum magnification can be attained only at 200 times so that the phenomenon of interaction layer and small gas bubble can not be observed. However, U 3 Si 2 /Al microstructure of 56 % burnup, if compared to the microstructure of U 3 Si 2 /Al fuel element plate of 60 % burnup from previous researcher, shows interaction between U 3 Si 2 meat with Al matrix and the existence of layers with a thickness about 5 up to 20 microns. Meanwhile, the observed thickness of AlMg 2 cladding is greater than 0.25 mm, which indicates that irradiation does not significantly change the thickness of AlMg 2 cladding so that the overall irradiated U 3 Si 2 -Al still has good integrity and stability. (author)

Split-Family SUSY, U(2)^5 Flavour Symmetry and Neutrino Physics

CERN Document Server

Jones-Pérez, Joel

2014-01-01

In split-family SUSY, one can use a U(2)^3 symmetry to protect flavour observables in the quark sector from SUSY contributions. However, attempts to extend this procedure to the lepton sector by using an analogous U(2)^5 symmetry fail to reproduce the neutrino data without introducing some form of fine-tuning. In this work, we solve this problem by shifting the U(2)^2 symmetry acting on leptons towards the second and third generations. This allows neutrino data to be reproduced without much difficulties, as well as protecting the leptonic flavour observables from SUSY. Key signatures are a $\\mu\\to e\\gamma$ branching ratio possibly observable in the near future, as well as having selectrons as the lightest sleptons.

{sup 4}He channelling studies of U{sub 4}O{sub 9}

Energy Technology Data Exchange (ETDEWEB)

Garrido, Frederico [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, CNRS-IN2P3-Universite Paris-Sud, Batiments 104-108, 91405 Orsay (France)]. E-mail: garrido@csnsm.in2p3.fr; Nowicki, Lech [The Andrzej Soltan Institute for Nuclear Studies, Hoza 69, 00-681 Warsaw (Poland); Stonert, Anna [Andrzej Soltan Institute for Nuclear Studies, Hoza 69, 00-681 Warsaw (Poland); Pietraszko, Adam [Institute for Low Temperature and Structural Research, Polish Academy of Science, 50-422 Wroclaw (Poland); Wendler, Elke [Institut fuer Festkoerperphysik, Friedrich-Schiller Universitaet Jena, 07743 Jena (Germany)

2006-08-15

UO{sub 2} and U{sub 4}O{sub 9} single crystals were investigated by means of the {sup 4}He backscattering/channelling technique and the use of the 3032-keV elastic scattering resonance on {sup 16}O. Angular scans obtained for U{sub 4}O{sub 9} were interpreted in the framework of a recently published U{sub 4}O{sub 9} model. It was shown that the U{sub 4}O{sub 9} channelling data can be explained by the aggregation of some O atoms in cuboctahedral clusters, and the displacement of other (U and O) atoms from the UO{sub 2}-type sites. Basing on the combined use of the channelling technique and Monte Carlo simulations we suggest that the displacements of U atoms from their fluorite sites are larger than those determined by the neutron diffraction analysis.

Flipped SU(5) times U(1) in superconformal models

Energy Technology Data Exchange (ETDEWEB)

Bailin, D.; Katechou, E.K. (Sussex Univ., Brighton (United Kingdom). School of Mathematical and Physical Sciences); Love, A. (London Univ. (United Kingdom))

1992-01-10

This paper reports that flipped SU(5) {times} U(1) models are constructed in the framework of tensoring of N = 2 superconformal minimal models quotiented by discrete symmetries. Spontaneous breaking of flipped SU(5) {times} U(1) and extra U(1) factors in the gauge group along F-flat directions of the effective potential is studied.

XPS study of U, UNi5, UCu5 and UNisub(0.5)Cusub(4.5)

International Nuclear Information System (INIS)

Grohs, H.; Hoechst, H.; Steiner, P.; Huefner, S.; Buschow, K.H.J.

1980-01-01

Core and valence band spectra of U metal and the intermetallic compounds UNi 5 , UCu 5 and UNisub(0.5)Cusub(4.5) have been measured by X-ray excited photoelectron spectroscopy (XPS). The data indicate that in UNi 5 the configuration is 5f 3 , and in UCu 5 and UNisub(0.5)Cusub(4.5) a mixed valence configuration with fewer 5f electrons than in UNi 5 is present. (author)

Mathematical modeling of the radiation-chemical oxidation of U(IV) in HClO4

International Nuclear Information System (INIS)

Vladimirova, M.V.

1995-01-01

Mathematical modeling of U(IV) oxidation in 0.5-12 M HClO 4 upon α, γ-radiolysis, based on the proposed scheme of radiation-chemical reactions, has been performed. The rate constants of the U(VI) + HO 2 , U(IV) + HO 2 , U(IV) + ClO 2 , and U(IV) + ClO 2 - reactions have been determined by the comparison of the calculated and experimental kinetic and dose curves and radiation-chemical yields of U(IV) oxidation or U(VI) formation. General equations for uranium (IV) oxidation constants at various HClO 4 concentrations, based on the analysis of the rates of particular radiation-chemical reactions composing oxidation process, have been obtained

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

Science.gov (United States)

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

Crystal structure of U2+xCo2Ga1-x

International Nuclear Information System (INIS)

Zelinskii, A.V.; Fedorchuk, A.A.

1995-01-01

In studies of phase equilibria in the U-Co-Ga system at 600 degrees C, the authors found a ternary compound close in composition to U 2 Co 2 Ga. A sample of composition U 42 Co 40 Ga 18 was prepared by arc-melting a mixture of high-purity U (99.4%), Co (99.99%), and Ga (99.99%) in a purified argon atmosphere. The sample was homogenized at 600 degrees C for 720 h in an evacuated quartz tube and then quenched in cold water. In structure determination, the authors used a DRON-4-07 powder X-ray diffractometer (CuK α radiation, 0.02 degrees 2θ scan step) and the CSD software package. The X-ray diffraction pattern showed tetragonal symmetry, with lattice parameters obtained from least-squares refinements a = 0.707729(5) and c = 0.34707(4) nm

Interdiffusion between U(Mo,Pt) or U(Mo,Zr) and Al or Al A356 alloy

International Nuclear Information System (INIS)

Komar Varela, C.; Mirandou, M.; Arico, S.; Balart, S.; Gribaudo, L.

2009-01-01

Solid state reactions in chemical diffusion couples U-7 wt.%Mo-0.9 wt.%Pt/Al at 580 deg. C and U-7 wt.%Mo-0.9 wt.%Pt/Al A356 alloy, U-7 wt.%Mo-1 wt.%Zr/Al and U-7 wt.%Mo-1 wt.%Zr/Al A356 alloy at 550 deg. C were characterized. Results were obtained from optical and scanning electron microscopy, electron probe microanalysis and X-ray diffraction. The UAl 3, UAl 4 and Al 20 Mo 2 U phases were identified in the interaction layers of γU(Mo,Pt)/Al and γU(Mo,Zr)/Al diffusion couples. Al 43 Mo 4 U 6 ternary compound was also identified in γU(Mo,Zr)/Al due to the decomposition of γU(Mo,Zr) phase. The U(Al,Si) 3 and U 3 Si 5 phases were identified in the interaction layers of γU(Mo,Pt)/Al A356 and γU(Mo,Zr)/Al A356 diffusion couples. These phases are formed due to the migration of Si to the interaction layer. In the diffusion couple U(Mo,Zr)/Al A356, Zr 5 Al 3 phase was also identified in the interaction layer. The use of synchrotron radiation at Brazilian Synchrotron Light Laboratory (LNLS, CNPq, Campinas, Brazil) was necessary to achieve a complete crystallographic characterization.

Monte Carlo analysis of the SU(2)xU(1) and U(2) lattice gauge theories at different space-time dimensionalities

International Nuclear Information System (INIS)

Baig, M.; Colet, J.

1986-01-01

Using Monte Carlo simulations the SU(2)xU(1) lattice gauge theory has been analyzed, which is equivalent for the Wilson action to a U(2) theory, at space-time dimensionalities from d=3 to 5. It has been shown that there exist first-order phase transitions for both d=4 and d=5. A monopole-condensation mechanism seems to be responsible for these phase transitions. At d=3 no phase transitions have been detected. (orig.)

Adaptable coordination of U(IV) in the 2D-(4,4) uranium oxalate network: From 8 to 10 coordinations in the uranium (IV) oxalate hydrates

International Nuclear Information System (INIS)

Duvieubourg-Garela, L.; Vigier, N.; Abraham, F.; Grandjean, S.

2008-01-01

Crystals of uranium (IV) oxalate hydrates, U(C 2 O 4 ) 2 .6H 2 O (1) and U(C 2 O 4 ) 2 .2H 2 O (2), were obtained by hydrothermal methods using two different U(IV) precursors, U 3 O 8 oxide and nitric U(IV) solution in presence of hydrazine to avoid oxidation of U(IV) into uranyl ion. Growth of crystals of solvated monohydrated uranium (IV) oxalate, U(C 2 O 4 ) 2 .H 2 O.(dma) (3), dma=dimethylamine, was achieved by slow diffusion of U(IV) into a gel containing oxalate ions. The three structures are built on a bi-dimensional complex polymer of U(IV) atoms connected through bis-bidentate oxalate ions forming [U(C 2 O 4 )] 4 pseudo-squares. The flexibility of this supramolecular arrangement allows modifications of the coordination number of the U(IV) atom which, starting from 8 in 1 increases to 9 in 3 and, finally increases, to 10 in 2. The coordination polyhedron changes from a distorted cube, formed by eight oxygen atoms of four oxalate ions, in 1, to a mono-capped square anti-prism in 3 and, finally, to a di-capped square anti-prism in 2, resulting from rotation of the oxalate ions and addition of one and two water oxygen atoms in the coordination of U(IV). In 1, the space between the ∞ 2 [U(C 2 O 4 ) 2 ] planar layers is occupied by non-coordinated water molecules; in 2, the space between the staggered ∞ 2 [U(C 2 O 4 ) 2 .2H 2 O] layers is empty, finally in 3, the solvate molecules occupy the interlayer space between corrugated ∞ 2 [U(C 2 O 4 ) 2 .H 2 O] sheets. The thermal decomposition of U(C 2 O 4 ) 2 .6H 2 O under air and argon atmospheres gives U 3 O 8 and UO 2 , respectively. - Graphical abstract: The adaptable environment of U(IV) in U(IV) oxalates: from eight cubic coordination in U(C 2 O 4 ) 2 .6H 2 O (a) completed by water oxygens to nine in [U(C 2 O 4 ) 2 .H 2 O](C 2 NH 5 ) (b) and ten coordination in U(C 2 O 4 ) 2 .2H 2 O (c)

Comparison of U-Pu-Mo, U-Pu-Nb, U-Pu-Ti and U-Pu-Zr alloys; Comparaison des alliages U-Pu-Mo, U-Pu-Nb, U-Pu-Ti, U-Pu-Zr

Energy Technology Data Exchange (ETDEWEB)

Boucher, R; Barthelemy, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1964-07-01

The data concerning the U-Pu, U-Pu-Mo and U-Pu-Nb are recalled. The results obtained with U-Pu-Ti and U-Pu-Zr alloys containing 15-20 per cent Pu and 10 wt. per cent ternary element are reported. The transformation temperatures, the expansion coefficients, the nature of phases, the thermal cycling behaviour have been determined. A list of the principal properties of these different alloys is presented and the possibilities of their use as fast reactor's fuel element are considered. The U-Pu-Ti alloys seem to be quite promising: easiness of fabrication, large thermal stability, excellent behaviour in air, small quantity of zeta phase, temperature of solidus superior to 1100 deg. C. (authors) [French] On rappelle brievement les connaissances acquises sur les alliages U-Pu, U-Pu-Mo et U-Pu-Nb. On presente les resultats obtenus avec les alliages U-Pu-Ti et U-Pu-Zr pour des teneurs de 15 a 20 pour cent de plutonium et 10 pour cent en poids d'element ternaire. On a determine les temperatures de transformation, les coefficients de dilatation, la nature des phases, la conductibilite thermique a 20 deg. C, la tenue au cyclage thermique et diverses autres proprietes. Un tableau resume les principales proprietes des divers alliages. On considere les possibilites d'emploi de ces alliages comme combustibles de reacteur rapide. Les alliages U-Pu-Ti paraissent particulierement interessants: facilite d'elaboration, stabilite thermique etendue, tenue dans l'air excellente, faible quantite de la phase U-Pu zeta, temperature de fusion commencante superieure a 1100 deg. C. (auteurs)

Supporting Table A4 MULLICAN CHARGES (a.u.) and ...

Indian Academy of Sciences (India)

Windows User

1.135621. 64 H. 0.01933. -1.132721. 65 H. -0.259245. -1.126795. Supporting Table A5. MULLICAN CHARGES (a.u.) and ELECTROSTATIC POTENTIAL(a.u.). OF ATOMS OF 1CH4@512-METHANOL. ATOM ID. ATOM TYPE MULLIKAN CHARGES.

Quantum algebra U{sub qp}(u{sub 2}) and application to the rotational collective dynamics of the nuclei; Algebre quantique U{sub qp}(u{sub 2}) et application a la dynamique collective de rotation dans les noyaux

Energy Technology Data Exchange (ETDEWEB)

Barbier, R

1995-09-22

This thesis concerns some aspects of new symmetries in Nuclear Physics. It comprises three parts. The first one is devoted to the study of the quantum algebra U{sub qp}(u{sub 2}). More precisely, we develop its Hopf algebraic structure and we study its co-product structure. The bases of the representation theory of U{sub qp}(u{sub 2}) are introduced. On one hand, we construct the finite-dimensional irreducible representations of U{sub qp}(u{sub 2}). On the other hand, we calculate the Clebsch-Gordan coefficients with the projection operator method. To complete our study, we construct some deformed boson mappings of the quantum algebras U{sub qp}(u{sub 2}), U{sub q{sup 2}}(su{sub 2}) and U{sub qp}(u{sub 1,1}). The second part deals with the construction of a new phenomenological model of the non rigid rotator. This model is based on the quantum algebra U{sub qp}(u{sub 2}). The rotational energy and the E2 reduced transition probabilities are obtained. They depend on the two deformation parameters q and p of the quantum algebra. We show how the use of the two-parameter deformation of the algebra U{sub qp}(u{sub 2}) leads to a generalization of the U{sub q}(su{sub 2})-rotator model. We also introduce a new model of the anharmonic oscillator on the basis of the quantum algebra U{sub qp}(u{sub 2}). We show that the system of the U{sub q}(su{sub 2})-rotator and of the anharmonic oscillator can be coupled with the use of the deformation parameters of U{sub qp}(u{sub 2}). A ro-vibration energy formula and expansion `a la` Dunham are obtained. The aim of the last part is to apply our non rigid rotator model to the rotational collective dynamics of the superdeformed nuclei of the A{approx}130 - 150 and A{approx}190 mass regions and deformed nuclei of the actinide and rare earth series. We adjust the free parameters of our model and compare our results with those from four other models of the non rigid rotator. A comparative analysis is given in terms of transition energies.

Isothermal section of diagram of U-Mo-B and U-Re-B systems

International Nuclear Information System (INIS)

Val'ovka, I.P.; Kuz'ma, Yu.B.

1986-01-01

The methods of X-ray analysis are used to study the U-Mo-B and U-Re-B systems and to plot phase equilibrium diagrams at 1000 and 800 deg C, respectively. A formation of boride UMoB 4 (structure of the ThMoB 4 type) is confirmed in the U-Mo-B system and new compounds are found: U 2 MoB 6 (rhombic structure of the Y 2 ReB 6 type, a=0.9301(9), b=1.1434(11), c=0.3678(4) nm), ∼UMo 2 B 6 and ∼ UMo 4 B 4 with unknown structures. In the U-Re-B system besides previously known boride UReB 4 (the ThMoB 4 structure type), new ones are obtained: U 2 ReB 6 (Y 2 ReB 6 type, a=0.9373(9), b=1.1529(13), c0.3653(4) nm) and UReB 3 (hexagonal structure of the proper type, a=0.5083(1), c=0.5095(1) nm)

Behavior of uranium along Jucar River (Eastern Spain). Determination of 234U/238U and 235U/238U ratios

International Nuclear Information System (INIS)

Rodriguez-Alvarez, M.J.; Sanchez, F.

1995-01-01

The uranium concentration and the 234 U/ 238 U, 235 U/ 238 U activity ratios were studied in water samples from Jucar River, using low-level α-spectrometry. The effects of pH, temperature and salinity were considered and more detailed sampling was done in the neighbourhood of Cofrentes Nuclear Plant (Valencia, Spain). Changes were observed in the uranium concentration with the salinity and the 234 U/ 238 U activity ratio was found to vary with pH. Leaching and dilution, which depend on pH and salinity, are the probable mechanisms for these changes in the concentration of uranium and the activity ratios. (author) 25 refs.; 4 figs.; 1 tab

Optical properties of LiYF4:U3+. Infrared laser use

International Nuclear Information System (INIS)

Louis, M.

1995-01-01

In this study are proposed a complete interpretation of the optical spectra of trivalent uranium in LiYF 4 (LYF). Single crystals of uranium doped LYF were grown by Czochralski method with different concentration (0.05%-0.20%). The obtained crystals have pale green color, characteristic of tetravalent uranium. The absorption spectra show that effectively only U 4+ is present in this crystal. In order to reduce the oxidation state of the U 4+ , the pale green crystal containing 0.07% of U 4+ was exposed to gamma irradiation. The sample becomes orange brown and the absorption spectrum is characteristic of U 3+ . The irradiation technology is an efficient method to convert 100% of U 4+ in U 3+ . From the analysis of the polarized optical absorption and emission spectra the spectroscopic parameters have been determined. The Judd-Ofelt theory was applied in order to simulate the intensity of the 5 f 3 →5 f 3 transitions between Stark levels of U 3+ in LYF. Because of the large crystal field splitting of the J multiplet in the actinides a set of phenomenological intensity parameters is introduced to describe the transition probabilities between crystal field sublevels. A continuous laser emission of an actinide ion at ambient temperature has been revealed. In the last part of this thesis the fundamental aspect of the energy transfer process that takes place in laser crystal LYF codoped with an 4 f element Nd 3+ and an 5 f one U 3+ has been investigated. (author). 111 refs., 69 figs., 19 tabs

A Comparison of the Variability of the Symbiotic X-ray Binaries GX 1+4, 4U 1954+31, and 4U 1700+24 from Swift/BAT and RXTE/ASM Observations

Science.gov (United States)

Corbet, R. H. D.; Sokoloski, J. L.; Mukai, K.; Markwardt, C. B.; Tueller, J.

2007-01-01

We present an analysis of the X-ray variability of three symbiotic X-ray binaries, GX 1+4, 4U 1700+24, and 4U 1954+31, using observations made with the Swift Burst Alert Telescope (BAT) and the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM). Observations of 4U 1954+31 with the Swift BAT show modulation at a period near 5 hours. Models to explain this modulation are discussed including the presence of an exceptionally slow X-ray pulsar in the system and accretion instabilities. We conclude that the most likely interpretation is that 4U 1954+31 contains one of the slowest known X-ray pulsars. Unlike 4U 1954+31, neither GX 1+4 nor 4U 1700+24 show any evidence for modulation on a timescale of hours. An analysis of the RXTE ASM light curves of GX l+4, 4U 1700+24, and 4U 1954+31 does not show the presence of periodic modulation in any source, although there is considerable variability on long timescales for all three sources. There is no modulation in GX 1+4 on either the optical 1161 day orbital period or a previously reported 304 day X-ray period. For 4U 1700+24 we do not confirm the 404 day period previously proposed for this source from a shorter duration ASM light curve.

Annex 5 - Fabrication of U-Al alloy; Prilog 5 - Dobijanje legure U-Al

Energy Technology Data Exchange (ETDEWEB)

Drobnjak, Dj; Lazarevic, Dj; Mihajlovic, A [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

1961-12-15

Alloy U-Al with low content of aluminium is often used for fabrication of fuel elements because it is stable under moderate neutron flux density. Additionally this type of alloys show much better characteristics than pure uranium under reactor operating conditions (temperature, mechanical load, corrosion effect of water). This report contains the analysis of the phase diagram of U-Al alloy with low content of aluminium, applied procedure for alloying and casting with detailed description of equipment. Characteristics of the obtained alloy are described and conclusions about the experiment and procedure are presented. Sistem U-Al sa niskim sadrzajem aluminijuma jedan je od cesto koriscenih za izradu gorivnih elemenata, jer je dovoljno stabilan pri umerenim gustinama fluksa. Pored toga, u uslovima karakteristicnim za rad nuklearnog reaktora (temperatura, gradijent temperature, mehanicka naprezanja, koroziono dejstvo vode) legure ovog sistema pokazuju daleko bolja svojstva od nelegiranog urana. Referat sadrzi analizu dijagrama stanja U-Al legure sa niskim sadrzajem aluminijuma, primenjeni postupak legiranja i livenja sa opisom pojedinih uredjaja i operacija. Takodje su opisana svojstva dobijene legure i dat je zakljucak o eksperimentu i tehnici rada (author)

Atomistic simulations of nanocrystalline U0.5Th0.5O2 solid solution under uniaxial tension

Directory of Open Access Journals (Sweden)

Hongxing Xiao

2017-12-01

Full Text Available Molecular dynamics simulations were performed to investigate the uniaxial tensile properties of nanocrystalline U0.5Th0.5O2 solid solution with the Born–Mayer–Huggins potential. The results indicated that the elastic modulus increased linearly with the density relative to a single crystal, but decreased with increasing temperature. The simulated nanocrystalline U0.5Th0.5O2 exhibited a breakdown in the Hall–Petch relation with mean grain size varying from 3.0 nm to 18.0 nm. Moreover, the elastic modulus of U1-yThyO2 solid solutions with different content of thorium at 300 K was also studied and the results accorded well with the experimental data available in the literature. In addition, the fracture mode of nanocrystalline U0.5Th0.5O2 was inclined to be ductile because the fracture behavior was preceded by some moderate amount of plastic deformation, which is different from what has been seen earlier in simulations of pure UO2.

Involvement of reversible binding to alpha 2u-globulin in 1,4-dichlorobenzene-induced nephrotoxicity.

Science.gov (United States)

Charbonneau, M; Strasser, J; Lock, E A; Turner, M J; Swenberg, J A

1989-06-01

Similarly to unleaded gasoline, 1,4-dichlorobenzene (1,4-DCB) administered for 2 years caused a dose-related increase in the incidence of renal tumors in male but not in female rats or in either sex of mice. Unleaded gasoline and 2,2,4-trimethylpentane (TMP), a component of unleaded gasoline, increased protein droplet formation and cell proliferation in male but not in female rat kidneys. These protein droplets contained, alpha 2u-globulin, a male rat-specific low-molecular-weight protein and 2,4,4-trimethyl-2-pentanol, a metabolite of TMP that was reversibly bound to this protein. Studies were undertaken to determine if 1,4-DCB produced similar effects; 1,2-DCB was used for comparison since it did not produce renal carcinogenesis in male rats. Gel filtration chromatography of a 116,000g supernatant prepared from kidneys of 1,4-[14C]DCB-treated rats showed that radiolabel coeluted with alpha 2u-globulin as one sharp peak as opposed to a multipeak pattern observed for 1,2-[14C]DCB; the maximal quantity of radiolabel for 1,4-DCB was twice that for 1,2-DCB. Equilibrium dialysis of kidney cytosol in the presence or absence of sodium dodecyl sulfate demonstrated that the radiolabel was reversibly bound to alpha 2u-globulin; the amount for 1,4-[14C]DCB-treated rats was almost twice as much as that for 1,2-[14C]DCB-treated rats. 1,2-DCB was also shown to be covalently bound to renal alpha 2u-globulin, and covalently bound to liver and plasma high-molecular-weight proteins. 1,4-DCB and, to a minor extent, 2,5-dichlorophenol, the major metabolite of 1,4-DCB, were reversibly bound to renal alpha 2u-globulin from 1,4-DCB-treated rats. 1,4-DCB increased protein droplet formation in male but not in female rat kidneys, whereas equimolar doses of 1,2-DCB showed no effect in either sex. Renal cell proliferation, measured by [3H]thymidine incorporation into renal DNA, was increased after 1,4-DCB but not after 1,2-DCB treatment. Nephrotoxicity and biochemical alterations induced by

Hydrogen absorption properties of U6Mn and U6Ni

International Nuclear Information System (INIS)

Ito, H.; Yamawaki, M.; Yamamoto, T.

1998-01-01

The hydrogen absorption properties of U, U 6 Mn and U 6 Ni were investigated at hydrogen pressures below 10 5 Pa. The pressure-composition (P-C) isotherms of U, U 6 Mn and U 6 Ni were obtained and the amounts of absorbed hydrogen for U, U 6 Mn and U 6 Ni were determined to be 3, 16.6 and 16.0 for x in MH x , where M is U, U 6 Mn and U 6 Ni, respectively. The desorption plateau pressures at 573 K decreased in the order: U 6 Mn-H>U 6 Ni-H>U-H. In addition, the results for the amounts of absorbed hydrogen suggests the formation of ternary hydrides U 6 MnH 18 and U 6 NiH 14 . (orig.)

Microstructure of the irradiated U 3Si 2/Al silicide dispersion fuel

Science.gov (United States)

Gan, J.; Keiser, D. D.; Miller, B. D.; Jue, J.-F.; Robinson, A. B.; Madden, J. W.; Medvedev, P. G.; Wachs, D. M.

2011-12-01

The silicide dispersion fuel of U 3Si 2/Al is recognized as the best performance fuel for many nuclear research and test reactors with up to 4.8 gU/cm 3 fuel loading. An irradiated U 3Si 2/Al dispersion fuel ( 235U ˜ 75%) from the high-flux side of a fuel plate (U0R040) from the Reduced Enrichment for Research and Test Reactors (RERTR)-8 test was characterized using transmission electron microscopy (TEM). The fuel was irradiated in the Advanced Test Reactor (ATR) for 105 days. The average irradiation temperature and fission density of the U 3Si 2 fuel particles for the TEM sample are estimated to be approximately 110 °C and 5.4 × 10 27 f/m 3. The characterization was performed using a 200-kV TEM. The U/Si ratio for the fuel particle and (Si + Al)/U for the fuel-matrix-interaction layer are approximately 1.1 and 4-10, respectively. The estimated average diameter, number density and volume fraction for small bubbles (<1 μm) in the fuel particle are ˜94 nm, 1.05 × 10 20 m -3 and ˜11%, respectively. The results and their implication on the performance of the U 3Si 2/Al silicide dispersion fuel are discussed.

Isotope shift of 234U, 236U, 238U in U I

International Nuclear Information System (INIS)

Gagne, J.M.; Nguyen Van, S.; Saint-Dizier, J.P.; Pianarosa, P.

1976-01-01

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

Anti-U-like as an alloantibody in S-s-U- and S-s-U+(var) black people.

Science.gov (United States)

Peyrard, Thierry; Lam, Yin; Saison, Carole; Arnaud, Lionel; Babinet, Jérôme; Rouger, Philippe; Bierling, Philippe; Janvier, Daniel

2012-03-01

S, s, and U antigens belong to the MNS system. They are carried by glycophorin B (GPB), encoded by GYPB. Black people with the low-prevalence S-s- phenotype, either U- or U+(var), can make a clinically significant anti-U. Anti-U-like, a cold immunoglobulin G autoantibody quite commonly observed in S-s+U+ black persons, was previously described to be nonreactive with ficin-, α-chymotrypsin-, and pronase-treated red blood cells (RBCs); nonreactive or weakly reactive with papain-treated RBCs; and reactive with trypsin-treated RBCs. Here we describe, in S-s- people from different molecular backgrounds, an alloantibody to a high-prevalence GPB antigen, which presents the same pattern of reactivity with proteases as autoanti-U-like. Four S-s- patients with an alloantibody to a high-prevalence GPB antigen were investigated by serologic and molecular methods. An alloantibody was observed in two S-s-U-/Del GYPB, one S-s-U+(var)/GYPB(P2), and one S-s-U+(var)/GYPB(NY) patients. As this alloantibody showed the same pattern of reactivity with proteases as autoanti-U-like, we decided to name it "anti-U-like." Anti-U-like made by the two S-s-U- patients was reactive with the S-s-U+(var) RBCs of the two other patients. S-s-U-/Del GYPB, S-s-U+(var)/GYPB(P2), and S-s-U+(var)/GYPB(NY) patients can make an alloanti-U-like. Anti-U-like made by S-s-U- people appears reactive with GYPB(P2) and GYPB(NY) RBCs, which both express a weak and partial U-like reactivity. We recommend transfusing S-s-U- RBCs in S-s-U- patients showing alloanti-U-like. Our study contributes to a better understanding of alloimmunization to GPB in black people and confirms importance of genotyping in S-s- patients, especially those with sickle cell disease to be frequently transfused. © 2011 American Association of Blood Banks.

A contribution to the kinetic study of the metatectic reaction U+U{sub 3}Si{sub 2}{yields}U{sub 3}Si; Contribucion al Estudio cinetico de la Reaccion Metatectica U+U{sub 3}Si{sub 2} U{sub 3}Si

Energy Technology Data Exchange (ETDEWEB)

Arroyo Ruiperez, J; Esteban Hernandez, J A

1962-07-01

An experimental study has been made to decide upon the advantages and drawbacks of the different methods and reagents employed in the metallography of U-Si alloys. It has been observed that all samples thermally treated to form the epsilon-phase undergo from the beginning a coalescence of the U{sub 3}Si{sub 2} particles, which makes practically useless any fine state of dispersion that might be present originally, as recommended by some authors. The coalescence of the U{sub 3}Si{sub 2} particle decreases the surface available for reaction and consequently the reaction rate. (Author) 7 refs.

Stress corrosion of the alloy U-7.5 Nb-2.5 Zr

International Nuclear Information System (INIS)

Lepoutre, D.; Nomine, A.M.; Miannay, D.

1983-09-01

Oxide formed on U-7.5 Nb-2.5 Zr at room temperature during stress corrosion cracking in oxygen is identical to the natural oxide of the alloy. It is formed by UO 2 with Nb and Zr and is associated with an increased Nb content at the interface. This oxide would be responsible for cracking [fr

INTEGRAL observation of renewed activity from 4U 1608-522

DEFF Research Database (Denmark)

Ishibashi, W.; Ferrigno, C.; Sánchez-Fernández, C.

2010-01-01

On 3 March 2010 SuperAGILE detected an X-ray burst from the LMXB 4U 1608-522 (Atel #2461). Confirmation of the renewed activity of this transient source was reported by MAXI/GSC (Atel #2462). 4U1608-522 was in the IBIS/ISGRI and JEMX field of view during several observations between 2010-Feb-23 06......, the source was not detected by IBIS/ISGRI. We derive an upper limit (5-sigma) on the X-ray flux of 5-10 mCrab in the 20-40 keV band. INTEGRAL is currently observing the field of GX 339-4 (March 4th-6th) and will continue monitoring of the inner Galactic Disk until the end of March. 4U 1608...

The Influence of Uranium Content and PVA/U Ratio on Physical Propertiesof PVA-U Gel and Its Oxide

International Nuclear Information System (INIS)

Damunir; W, Bangun; Indra-Suryawan; Endang-Nawangsih

2000-01-01

The influence of uranium content and PVA/U ratio on physical propertiesof PVA-U gel and its oxide has been investigated. Fifty milliliters of uranylnitrate solution containing 100 g U/l was neutralized using 1M NH 4 0H. Thesolution was converted into PVA-U sol by adding 9.18 % PVA while mixed andheated at 80 o C for 20 minutes. In order to find spherical gel, the solsolution was dropped into a 5 M NH 4 0H solution at room temperature. Theshape formed of the gels small spherical, shape of the formed gels werefiltered, washed and heated at 120 o C. After that the gels were calcined at800 o C for 4 hours. The formed U 3 O 8 particles. Under a similar method, theinfluence of uranium content from 150-400 g/l and the influence of PVA/Uratio of 6.5-12.5 % in 100 g U/l were studied. Characterization of the resultwas obtained from physical properties of the gel and its oxide in the form ofdensity using pycnometer, surface area using surface areameter with N 2 asabsorbent and particle size/ shape using a loop and optical microscope. Theexperimental results showed that both uranium content and PVA/U ratioaffected the physical properties of the kernel properties. The best resultoccurred at uranium content of 100 g/l and PVA/U 9.18 %. The resulted gelwith solid content of 89.17 %, density of 3.36 g/l and size of 124 μm. Theresulted oxide U 3 0 8 had density of 7.98 g U/l, surface area of specific of0.449 m 2 /g and grain size of 810 μm. (author)

O(5) x U(1) electroweak theory

International Nuclear Information System (INIS)

Mukku, C.; Sayed, W.A.

1981-01-01

An anomaly-free O(5) x U(1) theory of electroweak interactions is described which provides a unified description of electroweak phenomena for two families of standard leptons and quarks. No ''new'' nonsequential-type fermions are introduced, unlike the case for all past studies based on this group. The present scheme requires the introduction of two further charged and three more neutral gauge fields over and above those of SU(2) x U(1) giving rise to new neutral and charged currents

Determination of the isotopic ratio 234 U/238 U and 235 U/238 U in uranium commercial reagents by alpha spectroscopy

International Nuclear Information System (INIS)

Iturbe G, J.L.

1990-02-01

In this work the determination of the isotope ratio 234 U/ 238 U and 235 U/ 238 U obtained by means of the alpha spectroscopy technique in uranium reagents of commercial marks is presented. The analyzed uranium reagents were: UO 2 (*) nuclear purity, UO 3 (*) poly-science, metallic uranium, uranyl nitrate and uranyl acetate Merck, uranyl acetate and uranyl nitrate Baker, uranyl nitrate (*) of the Refinement and Conversion Department of the ININ, uranyl acetate (*) Medi-Lab Sigma of Mexico and uranyl nitrate Em Science. The obtained results show that the reagents that are suitable with asterisk (*) are in radioactive balance among the one 234 U/ 238 U, since the obtained value went near to the unit. In the case of the isotope ratio 235 U/ 238 U the near value was also obtained the one that marks the literature that is to say 0.04347, what indicates that these reagents contain the isotope of 235 U in the percentage found in the nature of 0.71%. The other reagents are in radioactive imbalance among the 234 U/ 238 U, the found values fluctuated between 0.4187 and 0.1677, and for the quotient of activities 235 U/ 238 U its were of 0.0226, and the lowest of 0.01084. Also in these reagents it was at the 236 U as impurity. The isotope of 236 U is an isotope produced artificially, for what is supposed that the reagents that are in radioactive imbalance were synthesized starting from irradiated fuel. (Author)

Compact toroid injection into C-2U

Science.gov (United States)

Roche, Thomas; Gota, H.; Garate, E.; Asai, T.; Matsumoto, T.; Sekiguchi, J.; Putvinski, S.; Allfrey, I.; Beall, M.; Cordero, M.; Granstedt, E.; Kinley, J.; Morehouse, M.; Sheftman, D.; Valentine, T.; Waggoner, W.; the TAE Team

2015-11-01

Sustainment of an advanced neutral beam-driven FRC for a period in excess of 5 ms is the primary goal of the C-2U machine at Tri Alpha Energy. In addition, a criteria for long-term global sustainment of any magnetically confined fusion reactor is particle refueling. To this end, a magnetized coaxial plasma-gun has been developed. Compact toroids (CT) are to be injected perpendicular to the axial magnetic field of C-2U. To simulate this environment, an experimental test-stand has been constructed. A transverse magnetic field of B ~ 1 kG is established (comparable to the C-2U axial field) and CTs are fired across it. As a minimal requirement, the CT must have energy density greater than that of the magnetic field it is to penetrate, i.e., 1/2 ρv2 >=B2 / 2μ0 . This criteria is easily met and indeed the CTs traverse the test-stand field. A preliminary experiment on C-2U shows the CT also capable of penetrating into FRC plasmas and refueling is observed resulting in a 20 - 30% increase in total particle number per single-pulsed CT injection. Results from test-stand and C-2U experiments will be presented.

Paramagnetic properties of the (U1-xTbx)Co2Ge2 solid solutions

International Nuclear Information System (INIS)

Kuznietz, Moshe; Pinto, Haim; Ettedgui, Hanania

1995-01-01

Polycrystalline (U 1-x Tb x )Co 2 Ge 2 solid solutions have the ThCr 2 Si 2 -type crystal structure and order antiferromagnetically. AC-susceptibility at 80-295 K yields paramagnetic Curie temperatures θ=-350±50, -15±5, -50±15, -12±5, and -80±5 K, and effective magnetic moments μ eff =4.5, 5.9, 7.3, 8.5, and 12.0 (±0.5)μ B , for samples with x=0, 0.25, 0.50, 0.75 and 1, respectively. The high μ eff values are related to occurrence of paramagnetic moments on U, Tb and Co, of which only U and Tb moments order magnetically. ((orig.))

Emergence of a new S U (4 ) symmetry in the baryon spectrum

Science.gov (United States)

Denissenya, M.; Glozman, L. Ya.; Pak, M.

2015-10-01

Recently, a large degeneracy of J =1 mesons—that is, larger than the S U (2 )L×S U (2 )R×U (1 )A symmetry of the QCD Lagrangian—has been discovered upon truncation of the near-zero modes from the valence quark propagators. It has been found that this degeneracy represents the S U (4 ) group that includes the chiral rotations as well as the mixing of left- and right-handed quarks. This symmetry group turns out to be a symmetry of confinement in QCD. Consequently, one expects that the same symmetry should persist upon the near-zero mode removal in other hadron sectors as well. It has been shown that indeed the J =2 mesons follow the same symmetry pattern upon the low-lying mode elimination. Here we demonstrate the S U (4 ) symmetry of baryons once the near-zero modes are removed from the quark propagators. We also show a degeneracy of states belonging to different irreducible representations of S U (4 ). This implies a larger symmetry that includes S U (4 ) as a subgroup.

Metallurgical characterization of melt-spun ribbons of U-5.4 wt%Nb alloy

Science.gov (United States)

Ma, Rong; Ren, Zhiyong; Tang, Qingfu; Chen, Dong; Liu, Tingyi; Su, Bin; Wang, Zhenhong; Luo, Chao

2018-06-01

The microstructures and micro-mechanical properties of the melt-spun ribbons of U-5.4 wt%Nb alloy were characterized using optical microscopy, scanning electron microscopy, X-ray diffraction and nanoindentation. Observed variations in microstructures and properties are related to the changes in ribbon thicknesses and cooling rates. The microstructures of the melt-spun ribbon consist of fine-scale columnar grains (∼1 μm) adjacent to the chill surface and coarse cellular grains in the remainder of the ribbon. In addition, the formation of inclusions in the ribbon is suppressed kinetically due to the high cooling rate during melt spinning. Compared with the water-quenched specimen prepared by traditional gravity casting and solution heat treatment, the elastic modulus values of the U-5.4 wt%Nb alloy were examined to vary with grain size and exhibited diverse energy dissipation capacities.

O(5) x U(1) electroweak theory

International Nuclear Information System (INIS)

Mukku, C.; Sayed, W.A.

1980-12-01

An anomaly free O(5) x U(1) theory of electroweak interactions is described which provides a unified description of electroweak phenomena for two families of standard leptons and quarks. No ''new'' non-sequential type fermions of the standard model are introduced as has been the case for all past studies based on this group. The present scheme requires the introduction of two further charged and three more neutral gauge fields over and above the Wsup(+-), Z and photon fields of SU(2) x U(1) giving rise to new neutral and charged currents. In this note we outline our reasons for proposing the present electroweak scheme, give the basic structure of the model, discuss the symmetry breaking pattern which ensures that SU(2)sub(L) x U(1) is the low energy symmetry, point out the new interactions present in the extended framework and obtain limits on the masses of all the gauge fields. (author)

22 CFR 127.4 - Authority of U.S. Immigration and Customs Enforcement and U.S. Customs and Border Protection...

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Authority of U.S. Immigration and Customs Enforcement and U.S. Customs and Border Protection officers. 127.4 Section 127.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS VIOLATIONS AND PENALTIES § 127.4 Authority of U.S...

Informacioni sistemi u upravljanju rizicima u životnoj sredini

Directory of Open Access Journals (Sweden)

Dejan Inđić

2013-02-01

Full Text Available Normal 0 MicrosoftInternetExplorer4 Sažetak: Zemljotresi, poplave, nuklearni i hemijski akcidenti, zagađivanje vazduha, zemljišta i voda, ukazuju na sve veće prisustvo nesreća nastalih intenzivnim razvojem i često nekontrolisanom primenom tehnološkog razvoja. Pred društvo se postavlja problem kako se što bolje pripremiti, kako obezbediti veću usklađenost i funkcionisanje aktivnosti i mera za sprečavanje nastanka akcidentnih situacija i kako uneti promene u društveni i tehnološki razvoj koje će ići u korist prirode, ali i za dobrobit budućih generacija. U radu je prikazano korišćenje različitih informacionih sistema (IS u upravljanju rizicima u životnoj sredini i predlog za izradu jedinstvenog IS u Republici Srbiji.

A Realistic $U(2)$ Model of Flavor arXiv

CERN Document Server

Linster, Matthias

We propose a simple $U(2)$ model of flavor compatible with an $SU(5)$ GUT structure. All hierarchies in fermion masses and mixings arise from powers of two small parameters that control the $U(2)$ breaking. In contrast to previous $U(2)$ models this setup can be realized without supersymmetry and provides an excellent fit to all SM flavor observables including neutrinos. We also consider a variant of this model based on a $D_6 \\times U(1)_F$ flavor symmetry, which closely resembles the $U(2)$ structure, but allows for Majorana neutrino masses from the Weinberg operator. Remarkably, in this case one naturally obtains large mixing in the lepton sector from small mixing in the quark sector. The model also offers a natural option for addressing the Strong CP Problem and Dark Matter by identifying the Goldstone boson of the $U(1)_F$ factor as the QCD axion.

Excess of "2"3"6U in the northwest Mediterranean Sea

International Nuclear Information System (INIS)

Chamizo, E.; López-Lora, M.; Bressac, M.; Levy, I.; Pham, M.K.

2016-01-01

In this work, we present first "2"3"6U results in the northwestern Mediterranean. "2"3"6U is studied in a seawater column sampled at DYFAMED (Dynamics of Atmospheric Fluxes in the Mediterranean Sea) station (Ligurian Sea, 43°25′N, 07°52′E). The obtained "2"3"6U/"2"3"8U atom ratios in the dissolved phase, ranging from about 2 × 10"−"9 at 100 m depth to about 1.5 × 10"−"9 at 2350 m depth, indicate that anthropogenic "2"3"6U dominates the whole seawater column. The corresponding deep-water column inventory (12.6 ng/m"2 or 32.1 × 10"1"2 atoms/m"2) exceeds by a factor of 2.5 the expected one for global fallout at similar latitudes (5 ng/m"2 or 13 × 10"1"2 atoms/m"2), evidencing the influence of local or regional "2"3"6U sources in the western Mediterranean basin. On the other hand, the input of "2"3"6U associated to Saharan dust outbreaks is evaluated. An additional "2"3"6U annual deposition of about 0.2 pg/m"2 based on the study of atmospheric particles collected in Monaco during different Saharan dust intrusions is estimated. The obtained results in the corresponding suspended solids collected at DYFAMED station indicate that about 64% of that "2"3"6U stays in solution in seawater. Overall, this source accounts for about 0.1% of the "2"3"6U inventory excess observed at DYFAMED station. The influence of the so-called Chernobyl fallout and the radioactive effluents produced by the different nuclear installations allocated to the Mediterranean basin, might explain the inventory gap, however, further studies are necessary to come to a conclusion about its origin. - Highlights: • First "2"3"6U results in the northwest Mediterranean Sea are reported. • Anthropogenic "2"3"6U dominates the whole seawater column at DYFAMED station. • "2"3"6U deep-water column inventory exceeds by a factor of 2.5 the global fallout one. • Saharan dust intrusions are responsible for an annual "2"3"6U flux of 0.02 pg/m"2. • Further studies are necessary to explain the

Tetrahalide complexes of the [U(NR)2]2+ ion: synthesis, theory, and chlorine K-edge X-ray absorption spectroscopy.

Science.gov (United States)

Spencer, Liam P; Yang, Ping; Minasian, Stefan G; Jilek, Robert E; Batista, Enrique R; Boland, Kevin S; Boncella, James M; Conradson, Steven D; Clark, David L; Hayton, Trevor W; Kozimor, Stosh A; Martin, Richard L; MacInnes, Molly M; Olson, Angela C; Scott, Brian L; Shuh, David K; Wilkerson, Marianne P

2013-02-13

Synthetic routes to salts containing uranium bis-imido tetrahalide anions [U(NR)(2)X(4)](2-) (X = Cl(-), Br(-)) and non-coordinating NEt(4)(+) and PPh(4)(+) countercations are reported. In general, these compounds can be prepared from U(NR)(2)I(2)(THF)(x) (x = 2 and R = (t)Bu, Ph; x = 3 and R = Me) upon addition of excess halide. In addition to providing stable coordination complexes with Cl(-), the [U(NMe)(2)](2+) cation also reacts with Br(-) to form stable [NEt(4)](2)[U(NMe)(2)Br(4)] complexes. These materials were used as a platform to compare electronic structure and bonding in [U(NR)(2)](2+) with [UO(2)](2+). Specifically, Cl K-edge X-ray absorption spectroscopy (XAS) and both ground-state and time-dependent hybrid density functional theory (DFT and TDDFT) were used to probe U-Cl bonding interactions in [PPh(4)](2)[U(N(t)Bu)(2)Cl(4)] and [PPh(4)](2)[UO(2)Cl(4)]. The DFT and XAS results show the total amount of Cl 3p character mixed with the U 5f orbitals was roughly 7-10% per U-Cl bond for both compounds, which shows that moving from oxo to imido has little effect on orbital mixing between the U 5f and equatorial Cl 3p orbitals. The results are presented in the context of recent Cl K-edge XAS and DFT studies on other hexavalent uranium chloride systems with fewer oxo or imido ligands.

A Stable U Isotopic Perspective on the U Budget and Global Extent of Modern Anoxia in the Ocean.

Science.gov (United States)

Tissot, F.; Dauphas, N.

2015-12-01

Isotopic fractionation between U4+ and U6+makes U stable isotopes potential tracers of global paleoredox conditions. In this work [1], we put the U-proxy up to a test against a highly constrained system: the modern ocean. We measured a large number of seawater samples from geographically diverse locations and found that the open ocean has a homogenous isotopic composition at δ238USW= -0.392 ± 0.005 ‰ (rel. to CRM-112a). From our measurement of rock samples (n=64) and compilations of literature data (n=380), we then estimated the U isotopic compositions of the various reservoirs involved in the modern oceanic U budget, as well as the fractionation factors associated with U incorporation into those reservoirs. Using a steady-state model, we compared the isotopic composition of the seawater predicted by the four most recent U oceanic budgets [2-5] to the modern seawater value we measured. Three of these budgets [2-4] predict a seawater isotopic composition in very good agreement with the observed δ238USW, which strengthens our confidence in the isotopic fractionation factors associated with each deposition environment and the fact that U is at steady-state in the modern ocean. The U oceanic budget of Henderson and Anderson (2003) does not reproduce the observed seawater composition because the U flux to anoxic/euxinic sediments relative to the total U flux out of the ocean is high in their model, which our analysis shows cannot be correct. The U isotopic composition of seawater is used to constrain the extent of anoxia in the modern ocean (% of seafloor covered by anoxic/euxinic sediments), which is 0.21 ± 0.09 %. This work demonstrates that stable isotopes of U can indeed trace the extent of anoxia in the modern global ocean, thereby validating the application of U isotope measurements to paleoredox reconstructions. Based on the above work, we will present the best estimate of the modern oceanic U budget. [1] Tissot F.L.H., Dauphas N. (2015) Geochim Cosmochim

A contribution to the kinetic study of the metatectic reaction U+U3Si2→U3Si

International Nuclear Information System (INIS)

Arroyo Ruiperez, J.; Esteban Hernandez, J. A.

1962-01-01

An experimental study has been made to decide upon the advantages and drawbacks of the different methods and reagents employed in the metallography of U-Si alloys. It has been observed that all samples thermally treated to form the epsilon-phase undergo from the beginning a coalescence of the U 3 Si 2 particles, which makes practically useless any fine state of dispersion that might be present originally, as recommended by some authors. The coalescence of the U 3 Si 2 particle decreases the surface available for reaction and consequently the reaction rate. (Author) 7 refs

Joint U. S. --U. S. S. R. test of U. S. MHD electrode systems in U. S. S. R. U-02 MHD facility (phase I). Final report

Energy Technology Data Exchange (ETDEWEB)

Hosler, W R [ed.

1976-01-01

The first (Phase I) joint U.S.-U.S.S.R. test of U.S. electrode materials was carried out in Moscow between September 25 and October 8, 1975 in the Soviet U-02 MHD facility. The test procedure followed closely a predetermined work plan designed to test five different zirconia based materials and the cathode and anode electrode wall modules under MHD operating conditions. The materials which were selected were 88Zr0/sub 2/-12Y/sub 2/0/sub 3/, 82Zr0/sub 2/-18Ce02, 50Zr0/sub 2/-50Ce0/sub 2/, 25Zr0/sub 2/-75Ce0/sub 2/ and 20Zr0/sub 2/-78Ce0/sub 2/-2Ta/sub 2/0/sub 5/. The electrode modules were constructed by Westinghouse Research and Development Laboratory. Each of the five electrode materials had four different current densities established between the anode and cathode during the experiment which lasted a total of 127 hours. There were four main phases in the test schedule: (1) start-up of the channel over a specific heating period. No seed (K/sub 2/C0/sub 3/) introduction - 18 hours. (2) Electrical tests at operating temperature to investigate electro-physical characteristics of the channel and electrodes - 6 hours. (3) Operating life test - 94 hours. (4) Shut-down of the channel over a specific cool down period - 9 hours. All except six electrode pairs performed satisfactorily during the entire test. These were the pairs which were designated to carry maximum or near maximum current density. Five pairs failed early in the life test and the sixth pair failed in the last several hours. Failure was not due to the electrode materials, however, but due to lead-out melting caused by joule heating in the platinum wires. The U-02 facility is described and the operational parameters are given for each phase of the test. The electrode and insulating walls are described and the appropriate parameters that are used to predict the performance of the module are given.

Oxidation behaviour of plutonium rich (U, Pu)C and (U, Pu)O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Sali, S.K., E-mail: sksali@barc.gov.in [Fuel Chemistry Division (India); Kulkarni, N.K.; Phatak, Rohan [Fuel Chemistry Division (India); Agarwal, Renu [Product Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2016-10-15

Oxidation behaviour of (U{sub 0.3}Pu{sub 0.7})C{sub 1.06} was investigated in air by heating samples up to 1073 K and 1273 K. Thermogravimetry (TG) of the samples and X-ray powder diffraction (XRD) of the intermediate products were used to understand the phenomenon taking place during this process. Theoretical calculations were carried out to understand the multiple phase changes taking place during oxidation of carbide. Theoretical results were validated by XRD analysis of the products obtained at different stages of oxidation. The final oxidized products were found to be a single FCC phase with O/M = 2.15 (M = U + Pu). Oxidation kinetic studies of (U{sub 0.3}Pu{sub 0.7})O{sub 2} and (U{sub 0.47}Pu{sub 0.53})O{sub 2} were carried out in dry air, using thermogravimetry, under non-isothermal conditions. The activation energy of oxidation was found to be 49 and 70 kJ/mol, respectively. Lattice parameter dependence on Pu/M and O/M of plutonium rich mixed oxide (MOX) was established using combined results of XRD and TG analysis of (U{sub 0.3}Pu{sub 0.7})O{sub 2+x} and (U{sub 0.47}Pu{sub 0.53})O{sub 2+x}.

Microstructure studies of interdiffusion behavior of U{sub 3}Si{sub 2}/Zircaloy-4 at 800 and 1000 °C

Energy Technology Data Exchange (ETDEWEB)

He, Lingfeng, E-mail: Lingfeng.He@inl.gov; Harp, Jason M., E-mail: Jason.Harp@inl.gov; Hoggan, Rita E.; Wagner, Adrian R.

2017-04-01

Fuel swelling during normal reactor operations could lead to unfavorable chemical interactions when in contact with its cladding. As new fuel types are developed, it is crucial to understand the interaction behavior between fuel and its cladding. Diffusion experiments between U{sub 3}Si{sub 2} and Zricaloy-4 (Zry-4) were conducted at 800 and 1000 °C up to 100 h. The microstructure of pristine U{sub 3}Si{sub 2} and U{sub 3}Si{sub 2}/Zry-4 interdiffusion products were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) equipped with an energy dispersive X-ray spectroscopy (EDS) system. The primary interdiffusion product observed at 800 °C is ZrSi{sub 2}, with secondary phases of U-Zr in the Zry-4, and Fe-Cr-W-Zr-Si phases at Zry-4/ZrSi{sub 2} interface and Fe-Cr-U-Si phases at ZrSi{sub 2}/U-Si interface. The primary interdiffusion products at 1000 °C were Zr{sub 2}Si, U-Zr-Fe-Ni, U, U-Zr, and a low melting point phase U{sub 6}Fe.

7 CFR 51.2541 - U.S. Fancy, U.S. Extra No. 1, U.S. No. 1 And U.S. Select Grades.

Science.gov (United States)

2010-01-01

... PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Pistachio.... Fancy,” “U.S. Extra No. 1,” “U.S. No. 1,” and “U.S. Select” consists of pistachio nuts in the shell...

U(1) x U(1) x U(1) symmetry of the Kimura 3ST model and phylogenetic branching processes

International Nuclear Information System (INIS)

Bashford, J D; Jarvis, P D; Sumner, J G; Steel, M A

2004-01-01

An analysis of the Kimura 3ST model of DNA sequence evolution is given on the basis of its continuous Lie symmetries. The rate matrix commutes with a U(1) x U(1) x U(1) phase subgroup of the group GL(4) of 4 x 4 invertible complex matrices acting on a linear space spanned by the four nucleic acid base letters. The diagonal 'branching operator' representing speciation is defined, and shown to intertwine the U(1) x U(1) x U(1) action. Using the intertwining property, a general formula for the probability density on the leaves of a binary tree under the Kimura model is derived, which is shown to be equivalent to established phylogenetic spectral transform methods. (letter to the editor)

The possibility of the mixed valence state in the uranium intermetallic compounds: UCoGa5, U2Ru2Sn and U2RuGa8

International Nuclear Information System (INIS)

Troc, Robert

2007-01-01

The mixed valence (MV) phenomenon has been observed so far in a large number of various compounds but containing only lanthanides. These properties are usually associated with the mixing of the localised f-state and the band states. The usual valence state for magnetic uranium intermetallics is the trivalent state 5f 3 or hybridised 5f 2 6d 1 , both are nearly degenerate in energy and can compete for a stability of the compound. In some cases a gain in an energy minimum may be achieved by very fast fluctuating between these two states with a time of 10 -14 s, which does not allow to yield the ordered state even if the exchange interactions (favourite the U-U distances) would be able for that. The latter cases seem to concern the described here intermetallics: one ternary compound based on Co, UCoGa 5 , and the two uranium ternary compounds based on Ru, namely U 2 Ru 2 Sn and U 2 RuGa 8 which all crystallize in a tetragonal unit cell. All these compounds show a maximum in their temperature dependences of the magnetic susceptibility measured along and perpendicular to the c-axis. Such a behaviour, which is reminiscent of a number of Ce (Sm, Eu) and Yb compounds for which χ(T) has in the past been considered by Sales and Wohlleben (SW) by applying their ICF model or by Lawrance et al. following their scaling procedure. It turned out that these phenomenological models can also be applied to the considered here two Ru-based uranium ternaries from which some reliable energy parameters could be found. In order to further support the mixing valence scenario for the first such cases in uranium compounds presented here, the transport and thermodynamic properties are also discussed. However, some of the most important results confirming the MV state, e.g., in U 2 RuGa 8 , has recently been achieved from the inelastic neutron scattering performed in the Rutherford Appleton Laboratory on the ISIS facility. From these measurements a characteristic gap of 60 meV has been

Multichannel interactions in the (1σ/sub g/)2(1σ/sub u/)nsσ, ndλ(3Σ+/sub u/,3Σ+/sub u/,3Pi/sub u/,3Δ/sub u/) Rydberg structures of He2

International Nuclear Information System (INIS)

Ginter, D.S.; Ginter, M.L.

1988-01-01

We show that a minimal parameter coupled channel model based on eigenquantum defect theory can reproduce quantitatively the known Rydberg structures associated with six channels of nsσ,ndλ( 3 Σ + /sub u/, 3 Σ + /sub u/, 3 Pi/sub u/, 3 Δ/sub u/) v = 0 ancestry in He 2 . Except for a few levels affected by accidental perturbations, these extensive level structures can be reproduced to within average experimental uncertainties. Previously unreported spectral analyses for transitions to the b 3 Pi/sub g/ state from rotational levels in the nl channel segments with n = 12--18 are included in this work. These spectral transitions were predicted and observed in the early stages of this investigation and were used to determine a number of new energy levels for the n = 3--18 data base used in subsequent calculations. The model uses a U matrix modified slightly from a Hund's case (b) to case (d) transformation and energy dependent eigenquantum defects μ/sub α/. Discussed in detail is a specific 14 parameter representation for ∼500 energy levels in which 2 parameters modify U to include interactions between ns and nd and 12 parameters describe the variation of the μ/sub α/'s with energy

Comparison of U-Pu-Mo, U-Pu-Nb, U-Pu-Ti and U-Pu-Zr alloys

International Nuclear Information System (INIS)

Boucher, R.; Barthelemy, P.

1964-01-01

The data concerning the U-Pu, U-Pu-Mo and U-Pu-Nb are recalled. The results obtained with U-Pu-Ti and U-Pu-Zr alloys containing 15-20 per cent Pu and 10 wt. per cent ternary element are reported. The transformation temperatures, the expansion coefficients, the nature of phases, the thermal cycling behaviour have been determined. A list of the principal properties of these different alloys is presented and the possibilities of their use as fast reactor's fuel element are considered. The U-Pu-Ti alloys seem to be quite promising: easiness of fabrication, large thermal stability, excellent behaviour in air, small quantity of zeta phase, temperature of solidus superior to 1100 deg. C. (authors) [fr

Preparation of U-Si/U-Me (Me = Fe, Ni, Mn) aluminum-dispersion plate-type fuel (miniplates) for capsule irradiation

International Nuclear Information System (INIS)

Ugajin, Mitsuhiro; Itoh, Akinori; Akabori, Mitsuo

1993-06-01

Details of equipment installed, method adopted and final products were described on the preparation of uranium silicides and other fuels for capsule irradiation. Main emphasis was placed on the preparation of laboratory-scale aluminum-dispersion plate-type fuel (miniplates) loaded to the first and second JMTR silicide capsules. Fuels contained in the capsules are as follows: (A) uranium-silicide base alloys U 3 Si 2 , Mo- added U 3 Si 2 , U 3 Si 2 +U 3 Si, U 3 Si 2 +USi, U 3 Si, U 3 (Si 0.8 Ge 0.2 ), U 3 (Si 0.6 Ge 0.4 ) (B) U 6 Me-type alloys with higher uranium density U 6 Mn, U 6 Ni, U 6 (Fe 0.4 Ni 0.6 ), U 6 (Fe 0.6 Mn 0.4 ) The powder-metallurgical picture-frame method was adopted and laboratory-scale technique was established for the preparation of miniplates. As a result of inspection for capsule irradiation, miniplates were prepared to meet the requirements of specification. (author)

Structure and physical properties of ternary uranium transition-metal antimonides U3MSb5 (M = Zr, Hf, Nb)

International Nuclear Information System (INIS)

Tkachuk, Andriy V.; Muirhead, Craig P.T.; Mar, Arthur

2006-01-01

The ternary uranium transition-metal antimonides U 3 MSb 5 (M = Zr, Hf, Nb) were prepared by arc-melting reactions followed by annealing at 800 deg. C, or by use of a Sn flux. These compounds extend the previously known series U 3 MSb 5 (M = Ti, V, Cr, Mn) and RE 3 MSb 5 (RE = La, Ce, Pr, Nd, Sm; M = Ti, Zr, Hf, Nb). The crystal structures of U 3 MSb 5 were determined by single-crystal X-ray diffraction data (Pearson symbol hP18, hexagonal, space group P6 3 /mcm, Z = 2; U 3 ZrSb 5 , a = 9.2223(3) A, c = 6.1690(2) A; U 3 HfSb 5 , a = 9.2084(4) A, c = 6.1629(3) A; U 3 NbSb 5 , a = 9.1378(4) A, c 6.0909(6) A). U 3 TaSb 5 has also been identified in microcrystalline form (a = 9.233(3) A, c = 6.142(3) A). Four-probe electrical resistivity measurements on single crystals and dc magnetic susceptibility measurements on powders indicated prominent transitions that are attributed to ferromagnetic ordering. The Curie temperatures, T C , located from ac magnetic susceptibility curves, are 135 K for U 3 ZrSb 5 , 141 K for U 3 HfSb 5 , and 107 K for U 3 NbSb 5

Drosophila SMN complex proteins Gemin2, Gemin3, and Gemin5 are components of U bodies

International Nuclear Information System (INIS)

Cauchi, Ruben J.; Sanchez-Pulido, Luis; Liu, Ji-Long

2010-01-01

Uridine-rich small nuclear ribonucleoproteins (U snRNPs) play key roles in pre-mRNA processing in the nucleus. The assembly of most U snRNPs takes place in the cytoplasm and is facilitated by the survival motor neuron (SMN) complex. Discrete cytoplasmic RNA granules called U bodies have been proposed to be specific sites for snRNP assembly because they contain U snRNPs and SMN. U bodies invariably associate with P bodies, which are involved in mRNA decay and translational control. However, it remains unknown whether other SMN complex proteins also localise to U bodies. In Drosophila there are four SMN complex proteins, namely SMN, Gemin2/CG10419, Gemin3 and Gemin5/Rigor mortis. Drosophila Gemin3 was originally identified as the Drosophila orthologue of human and yeast Dhh1, a component of P bodies. Through an in silico analysis of the DEAD-box RNA helicases we confirmed that Gemin3 is the bona fide Drosophila orthologue of vertebrate Gemin3 whereas the Drosophila orthologue of Dhh1 is Me31B. We then made use of the Drosophila egg chamber as a model system to study the subcellular distribution of the Gemin proteins as well as Me31B. Our cytological investigations show that Gemin2, Gemin3 and Gemin5 colocalise with SMN in U bodies. Although they are excluded from P bodies, as components of U bodies, Gemin2, Gemin3 and Gemin5 are consistently found associated with P bodies, wherein Me31B resides. In addition to a role in snRNP biogenesis, SMN complexes residing in U bodies may also be involved in mRNP assembly and/or transport.

Drosophila SMN complex proteins Gemin2, Gemin3, and Gemin5 are components of U bodies

Energy Technology Data Exchange (ETDEWEB)

Cauchi, Ruben J.; Sanchez-Pulido, Luis [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX (United Kingdom); Liu, Ji-Long, E-mail: jilong.liu@dpag.ox.ac.uk [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX (United Kingdom)

2010-08-15

Uridine-rich small nuclear ribonucleoproteins (U snRNPs) play key roles in pre-mRNA processing in the nucleus. The assembly of most U snRNPs takes place in the cytoplasm and is facilitated by the survival motor neuron (SMN) complex. Discrete cytoplasmic RNA granules called U bodies have been proposed to be specific sites for snRNP assembly because they contain U snRNPs and SMN. U bodies invariably associate with P bodies, which are involved in mRNA decay and translational control. However, it remains unknown whether other SMN complex proteins also localise to U bodies. In Drosophila there are four SMN complex proteins, namely SMN, Gemin2/CG10419, Gemin3 and Gemin5/Rigor mortis. Drosophila Gemin3 was originally identified as the Drosophila orthologue of human and yeast Dhh1, a component of P bodies. Through an in silico analysis of the DEAD-box RNA helicases we confirmed that Gemin3 is the bona fide Drosophila orthologue of vertebrate Gemin3 whereas the Drosophila orthologue of Dhh1 is Me31B. We then made use of the Drosophila egg chamber as a model system to study the subcellular distribution of the Gemin proteins as well as Me31B. Our cytological investigations show that Gemin2, Gemin3 and Gemin5 colocalise with SMN in U bodies. Although they are excluded from P bodies, as components of U bodies, Gemin2, Gemin3 and Gemin5 are consistently found associated with P bodies, wherein Me31B resides. In addition to a role in snRNP biogenesis, SMN complexes residing in U bodies may also be involved in mRNP assembly and/or transport.

Chemical thermodynamic representation of (U, Pu, Am)O2-x

International Nuclear Information System (INIS)

Osaka, Masahiko; Namekawa, Takashi; Kurosaki, Ken; Yamanaka, Shinsuke

2005-01-01

The oxygen potential isotherms of (U, Pu, Am)O 2-x were represented by a chemical thermodynamic model proposed by Lindemer et al. It was assumed in the present model that (U, Pu, Am)O 2-x consisted of the chemical species [UO 2 ], [PuO 2 ], [Pu 4/3 O 2 ], [AmO 2 ] and [Am 5/4 O 2 ] in a pseudo-quaternary system by treating the reduction rates of Pu and Am as identical; furthermore an interaction between [Am 5/4 O 2 ] and [UO 2 ] was introduced. The agreement between analytical and experimental isotherms was good, but the analytical values slightly overestimated the experimental values especially in the case of lower Am content. Adding an interaction between [Am 5/4 O 2 ] and [PuO 2 ] to the model resulted in a better representation

Neutron inelastic-scattering cross sections of 232Th, 233U, 235U, 238U, 239Pu and 240Pu

International Nuclear Information System (INIS)

Smith, A.B.; Guenther, P.T.

1982-01-01

Differential-neutron-emission cross sections of 232 Th, 233 U, 235 U, 238 U, 239 Pu and 240 Pu are measured between approx. = 1.0 and 3.5 MeV with the angle and magnitude detail needed to provide angle-integrated emission cross sections to approx. 232 Th, 233 U, 235 U and 238 U inelastic-scattering values, poor agreement is observed for 240 Pu, and a serious discrepancy exists in the case of 239 Pu

Electron Loss from 1.4 MeV/u U^4,6,10+ Ions Colliding with Ne, N₂, and Ar Targets

CERN Document Server

Dubois, R D; Stöhlker, T; Bosch, F; Bräuning-Demian, A; Banas, D; Gumberidze, A; Hagmann, S; Kozhuharov, C; Mann, R; Orsic-Muthig, A; Spillmann, U; Tachenov, S; Bart, W; Dahl, L; Franzke, B; Glatz, J; Gröning, L; Richter, S; Wilms, D; Ullmann, K; Jagutzki, O

2004-01-01

Absolute, total, single, and multiple electron loss cross sections are measured for 1.4 MeV/u U4,6,10+ ions colliding with neon and argon atoms and nitrogen molecules. It is found that the cross sections all have the same dependence on the number of electrons lost and that multiplying the cross sections by the initial number of electrons in the 6s, 6p, and 5f shells yields good agreement between the different projectiles. By combining the present data with previous measurements made at the same velocity, it is shown that the scaled cross sections slowly decrease in magnitude for incoming charge states between 1 and 10 whereas the cross sections for higher charge state ions fall off much more rapidly.

U2 laulusõnade tundmine lennutab Hawaile

Index Scriptorium Estoniae

2006-01-01

Iiri bänd U2 algatas oma uue albumi "U2 18 Singles väljatuleku puhul internetis võistluse "Hunt The Lyric", kus fännidel on võimalus võita reis Hawaile (reisi paketis ka U2 "Vertigo" tuuri kontsert 9. dets.)

Dicty_cDB: Contig-U09345-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U09345-1 gap included 1216 4 3361857 3360637 MINUS 4 5 U09345 1 0 1 0 0 0 2 0 0 0 0 0 0 0 Show Contig...-U09345-1 Contig ID Contig-U09345-1 Contig update 2002. 9.13 Contig sequence >Contig-U09345-1 (Contig-U09345-1Q) /CSM_Contig/Contig-U0934...AATGGTATTTTAAAAATAA Gap gap included Contig length 1216 Chromosome number (1..6, M) 4 Chromosome length 5430...ALFTSSNPKYGCSGCVQLKNQIESFSLSYEPYL NSAGFLEKPIFIVILEVDYNMEVFQTIGLNTIPHLLFIPSGSKPITQKGYAYTGFEQTSS QSISDFIYSHSKI...LLALFTSSNPKYGCSGCVQLKNQIESFSLSYEPYL NSAGFLEKPIFIVILEVDYNMEVFQTIGLNTIPHLLFIPSGSKPI

Analysis of the right-handed Majorana neutrino mass in an S U (4 )×S U (2 )L×S U (2 )R Pati-Salam model with democratic texture

Science.gov (United States)

Yang, Masaki J. S.

2017-03-01

In this paper, we attempt to build a unified model with the democratic texture, that has some unification between up-type Yukawa interactions Yν and Yu . Since the S3 L×S3 R flavor symmetry is chiral, the unified gauge group is assumed to be Pati-Salam type S U (4 )c×S U (2 )L×S U (2 )R. The breaking scheme of the flavor symmetry is considered to be S3 L×S3 R→S2 L×S2 R→0 . In this picture, the four-zero texture is desirable for realistic masses and mixings. This texture is realized by a specific representation for the second breaking of the S3 L×S3 R flavor symmetry. Assuming only renormalizable Yukawa interactions, type-I seesaw mechanism, and neglecting C P phases for simplicity, the right-handed neutrino mass matrix MR can be reconstructed from low energy input values. Numerical analysis shows that the texture of MR basically behaves like the "waterfall texture." Since MR tends to be the "cascade texture" in the democratic texture approach, a model with type-I seesaw and up-type Yukawa unification Yν≃Yu basically requires fine-tunings between parameters. Therefore, it seems to be more realistic to consider universal waterfall textures for both Yf and MR, e.g., by the radiative mass generation or the Froggatt-Nielsen mechanism. Moreover, analysis of eigenvalues shows that the lightest mass eigenvalue MR 1 is too light to achieve successful thermal leptogenesis. Although the resonant leptogenesis might be possible, it also requires fine-tunings of parameters.

Convergence of exterior solutions to radial Cauchy solutions for $\\partial_t^2U-c^2\\Delta U=0$

Directory of Open Access Journals (Sweden)

Helge Kristian Jenssen

2016-09-01

Full Text Available Consider the Cauchy problem for the 3-D linear wave equation $\\partial_t^2U-c^2\\Delta U=0$ with radial initial data $U(0,x=\\Phi(x=\\varphi(|x|$, $U_t(0,x=\\Psi(x=\\psi(|x|$. A standard result states that $U$ belongs to $C([0,T];H^s(\\mathbb{R}^3$ whenever $(\\Phi,\\Psi\\in H^s\\times H^{s-1}(\\mathbb{R}^3$. In this article we are interested in the question of how U can be realized as a limit of solutions to initial-boundary value problems on the exterior of vanishing balls $B_\\varepsilon$ about the origin. We note that, as the solutions we compare are defined on different domains, the answer is not an immediate consequence of $H^s$ well-posedness for the wave equation.

Obtaining of U-2.5Zr7.5Nb and U-3Zr-9Nb alloys by sintering process

International Nuclear Information System (INIS)

Mazzeu, Thiago de Oliveira; Paula, Joao Bosco de; Ferraz, Wilmar Barbosa; Santos, Ana Maria Matildes dos; Brina, Jose Giovanni Mascarenhas

2011-01-01

The development of metallic fuels with low enrichment to be used in research and test reactors, as well in the future pressurized water reactors, focuses on the search for uranium alloys of high density. Alloying elements such as Zr, Nb and Mo are added to uranium to improve fuel performance in reactors. In this context, the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) in Belo Horizonte is developing the U-2.5Zr-7.5Nb and U- 3Zr-9Nb (weight %) alloys by the innovative process of sintering that utilizes raw materials in the form of powders. The powders were pressed at 400MPa and then sintered under a vacuum of about 5 x 10-6 Torr at temperatures ranging from 1050 deg to 1300 deg C. The densities of the alloys were measured geometrically and by hydrostatic method using water. The microstructures of the pellets were observed by scanning electron microscopy (SEM) and the elements of alloying were identified by energy dispersive X-ray spectroscopy (SEM/EDS) analysis. The obtained results showed a small increasing density with rising sintering temperature. The highest density achieved was approximately 80% of theoretical density. It was also qualitatively observed that the superficial oxidation of the pellets increased with increasing sintering temperature thus avoiding the fusion of the alloys at higher temperatures. (author)

K X-rays and nuclear reaction times in the deep inelastic reactions U+U and U+Pb at 7.5 MeV/amu

International Nuclear Information System (INIS)

Stoller, C.

1985-01-01

The K-shell ionisation probability of the heavy reaction products emerging from binary deep inelastic collisions of U + U and U + Pb at 7.5 MeV/amu has been measured as a function of the total kinetic energy loss - Q. After subtraction of the ionisation probability due to internal conversion of γ-rays, a strongly Q-dependent Psub(K) is found, in agreement with theoretical predictions relating the change in ionisation probability to the nuclear sticking time. The deduced nuclear reaction times are in qualitative agreement with predictions from nuclear models of deep inelastic reactions. (orig.)

Characteristics of chemical binding to alpha 2u-globulin in vitro--evaluating structure-activity relationships

International Nuclear Information System (INIS)

Borghoff, S.J.; Miller, A.B.; Bowen, J.P.; Swenberg, J.A.

1991-01-01

alpha 2u-Globulin (alpha 2u) has been shown to accumulate in the kidneys of male rats treated with 2,2,4-trimethylpentane (TMP). 2,4,4-Trimethyl-2-pentanol (TMP-2-OH), a metabolite of TMP, is found reversibly bound to alpha 2u isolated from the kidneys of these treated rats. The objectives of the following study were to characterize the ability of [3H]TMP-2-OH to bind to alpha 2u in vitro and to determine whether other compounds that cause this protein to accumulate have the same binding characteristics. Although compounds that have been shown to cause the accumulation of alpha 2u in male rat kidneys compete in vitro with [3H]TMP-2-OH for binding to alpha 2u, they do so to varying degrees. The binding affinity (Kd) of the [3H]TMP-2-OH-alpha 2u complex was calculated to be on the order of 10(-7) M. The inhibition constant values (Ki) determined for d-limonene, 1,4-dichlorobenzene, and 2,5-dichlorophenol were all in the range 10(-4) M, whereas the Ki values for isophorone, 2,4,4- or 2,2,4-trimethyl-1-pentanol, and d-limonene oxide were determined to be in the range 10(-6) and 10(-7) M, respectively. TMP and 2,4,4- and 2,2,4-trimethylpentanoic acid did not compete for binding. This suggests that other factors, besides binding, are involved in the accumulation of alpha 2u. In this study the ability of a chemical to bind to alpha 2u was used as a measure of biological activity to assess structure-activity relationships among the chemicals tested and known to cause the accumulation of alpha 2u. The results so far suggest that binding is dependent on both hydrophobic interactions and hydrogen bonding

Determination of the isotopic ratio {sup 234} U/{sup 238} U and {sup 235} U/{sup 238} U in uranium commercial reagents by alpha spectroscopy; Determinacion de la relacion isotopica {sup 234} U/{sup 238} U y {sup 235} U/{sup 238} U en reactivos comerciales de uranio por espectrometria alfa

Energy Technology Data Exchange (ETDEWEB)

Iturbe G, J L

1990-02-15

In this work the determination of the isotope ratio {sup 234} U/{sup 238} U and {sup 235} U/{sup 238} U obtained by means of the alpha spectroscopy technique in uranium reagents of commercial marks is presented. The analyzed uranium reagents were: UO{sub 2} (*) nuclear purity, UO{sub 3} (*) poly-science, metallic uranium, uranyl nitrate and uranyl acetate Merck, uranyl acetate and uranyl nitrate Baker, uranyl nitrate (*) of the Refinement and Conversion Department of the ININ, uranyl acetate (*) Medi-Lab Sigma of Mexico and uranyl nitrate Em Science. The obtained results show that the reagents that are suitable with asterisk (*) are in radioactive balance among the one {sup 234} U/{sup 238} U, since the obtained value went near to the unit. In the case of the isotope ratio {sup 235} U/{sup 238} U the near value was also obtained the one that marks the literature that is to say 0.04347, what indicates that these reagents contain the isotope of {sup 235} U in the percentage found in the nature of 0.71%. The other reagents are in radioactive imbalance among the {sup 234} U/{sup 238} U, the found values fluctuated between 0.4187 and 0.1677, and for the quotient of activities {sup 235} U/{sup 238} U its were of 0.0226, and the lowest of 0.01084. Also in these reagents it was at the {sup 236} U as impurity. The isotope of {sup 236} U is an isotope produced artificially, for what is supposed that the reagents that are in radioactive imbalance were synthesized starting from irradiated fuel. (Author)

MEDICIS(ASTEC-V2) sensitivity calculations for investigation of the crust formation in VB-U5 and VB-U6 VULCANO tests

International Nuclear Information System (INIS)

Stefanova, A.; Grudev, P.; Gencheva, R.

2011-01-01

This paper presents the results from sensitivity calculations made with MEDICIS(ASTECv2) for investigation of the crust formation during the Molten Corium-Concrete Interaction(MCCI) in VB-U5 and VB-U6 VULCANO tests. All calculations are made with MEDICIS computer code. The main goal of these analyses is to assess how the assumptions for crust formation or not formation influence over the concrete ablation. Three calculations have been done for each one of the experiments with different crust thickness and lock of crust formation at the bottom, side and upper surface. (authors)

Precise 238U(n,2n)237U reaction cross-section measurements using the activation facility at TUNL

Science.gov (United States)

Krishichayan, Fnu; Bhike, M.; Tornow, W.

2014-09-01

Accurate neutron-induced 238U(n,2n)237U reaction data are required for many practical applications, especially in the field of nuclear energy, including advanced heavy water reactors, where 238U is used as the breeding material to regenerate the fissile material 239Pu. Precise (n,2n) cross-section measurements of 238U are underway at TUNL with mono-energetic neutrons in the 8.0 to 14.0 MeV energy range in steps of 0.25 MeV using the activation technique. After activation of the 0.5 inch diameter and 442 mg 238U foil, the activity of the 208 keV characteristic γ-line is tracked for 6 weeks with a high efficient HPGe clover detector to determine the initial activity needed for the cross-section determination. Results of the cross-section measurements, determined relative to 27Al and 197Au neutron activation monitor foils, and the comparison with theoretical models will be presented during the meeting.

Azimuthal Anisotropy in U +U and Au +Au Collisions at RHIC

Science.gov (United States)

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandin, A. V.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, H. Z.; Huang, B.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Kosarzewski, L. K.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, W.; Li, Y.; Li, C.; Li, Z. M.; Li, X.; Li, X.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, L.; Ma, R.; Ma, Y. G.; Ma, G. L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D. L.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, S.; Raniwala, R.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B. J.; Sun, X.; Sun, X. M.; Sun, Z.; Sun, Y.; Surrow, B.; Svirida, D. N.; Szelezniak, M. A.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A. N.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbaek, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, F.; Wang, Y.; Wang, H.; Wang, J. S.; Wang, Y.; Wang, G.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, Y. F.; Xu, N.; Xu, Z.; Xu, Q. H.; Xu, H.; Yang, Y.; Yang, Y.; Yang, C.; Yang, S.; Yang, Q.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, X. P.; Zhang, J. B.; Zhang, J.; Zhang, Z.; Zhang, S.; Zhang, Y.; Zhang, J. L.; Zhao, F.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

2015-11-01

Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2 } and v2{4 }, for charged hadrons from U +U collisions at √{sNN }=193 GeV and Au +Au collisions at √{sNN}=200 GeV . Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v2{2 } on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U +U collisions. We also show that v2 vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.

Azimuthal Anisotropy in U+U and Au+Au Collisions at RHIC.

Science.gov (United States)

Adamczyk, L; Adkins, J K; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Bouchet, J; Brandin, A V; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Calderón de la Barca Sánchez, M; Campbell, J M; Cebra, D; Cervantes, M C; Chakaberia, I; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, J H; Chen, X; Cheng, J; Cherney, M; Christie, W; Contin, G; Crawford, H J; Das, S; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; di Ruzza, B; Didenko, L; Dilks, C; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Eppley, G; Esha, R; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, Z; Filip, P; Fisyak, Y; Flores, C E; Fulek, L; Gagliardi, C A; Garand, D; Geurts, F; Gibson, A; Girard, M; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, S; Gupta, A; Guryn, W; Hamad, A; Hamed, A; Haque, R; Harris, J W; He, L; Heppelmann, S; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, H Z; Huang, B; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Jiang, K; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Kosarzewski, L K; Kotchenda, L; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Li, W; Li, Y; Li, C; Li, Z M; Li, X; Li, X; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, L; Ma, R; Ma, Y G; Ma, G L; Magdy, N; Majka, R; Manion, A; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; Meehan, K; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Okorokov, V; Olvitt, D L; Page, B S; Pak, R; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlik, B; Pei, H; Perkins, C; Peterson, A; Pile, P; Planinic, M; Pluta, J; Poljak, N; Poniatowska, K; Porter, J; Posik, M; Poskanzer, A M; Pruthi, N K; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, S; Raniwala, R; Ray, R L; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Sharma, M K; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Sikora, R; Simko, M; Skoby, M J; Smirnov, D; Smirnov, N; Song, L; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stepanov, M; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Summa, B J; Sun, X; Sun, X M; Sun, Z; Sun, Y; Surrow, B; Svirida, D N; Szelezniak, M A; Tang, Z; Tang, A H; Tarnowsky, T; Tawfik, A N; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Tripathy, S K; Trzeciak, B A; Tsai, O D; Ullrich, T; Underwood, D G; Upsal, I; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Varma, R; Vasiliev, A N; Vertesi, R; Videbaek, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Vossen, A; Wang, F; Wang, Y; Wang, H; Wang, J S; Wang, Y; Wang, G; Webb, G; Webb, J C; Wen, L; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, Y F; Xu, N; Xu, Z; Xu, Q H; Xu, H; Yang, Y; Yang, Y; Yang, C; Yang, S; Yang, Q; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zbroszczyk, H; Zha, W; Zhang, X P; Zhang, J B; Zhang, J; Zhang, Z; Zhang, S; Zhang, Y; Zhang, J L; Zhao, F; Zhao, J; Zhong, C; Zhou, L; Zhu, X; Zoulkarneeva, Y; Zyzak, M

2015-11-27

Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v_{2}{2} and v_{2}{4}, for charged hadrons from U+U collisions at sqrt[s_{NN}]=193  GeV and Au+Au collisions at sqrt[s_{NN}]=200  GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v_{2}{2} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. We also show that v_{2} vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.

Modular metal chalcogenide chemistry: secondary building blocks as a basis of the silicate-type framework structure of CsLiU(PS_4)_2

International Nuclear Information System (INIS)

Neuhausen, Christine; Rocker, Frank; Tremel, Wolfgang

2012-01-01

The novel uranium thiophosphate CsLiU(PS_4)_2 has been synthesized by reacting uranium metal, Cs_2S, Li_2S, S, and P_2S_5 at 700 C in an evacuated silica tube. The crystal structure was determined by single-crystal X-ray diffraction techniques. CsLiU(PS_4)_2 crystallizes in the rhombohedral space group R anti 3c (a = 15.2797(7) Aa; c = 28.778(2) Aa, V = 5818.7(5) Aa"3, Z = 18). The structure of CsLiU(PS_4)_2 is a unique three-dimensional U(PS_4)_2"2"- framework with large tunnels with an approximate diameter of 6.6 Aa running parallel to the crystallographic c axis. The tunnels are filled with Cs"+ cations. The smaller Li"+ cations are located at tetrahedral sites at the periphery of the channels. In the structure of CsLiU(PS_4)_2 the uranium atoms are coordinated by thiophosphate groups in a pseudotetrahedral fashion, and the PS_4 groups act as linear connectors. Topologically, CsLiU(PS_4)_2 may be regarded a chalcogenide analogue of silicate frameworks, with the uranium atoms and PS_4 groups replacing silicon and oxygen atoms. Alternatively, CsLiU(PS_4)_2 may be viewed as a coordination polymer, which is formed in salt melts by the solid state equivalent of the ''self-assembly'' reactions in solution. Magnetic susceptibility measurements indicated Curie-Weiss-type behavior between 4 K and 300 K. The μ_e_f_f of 2.83 μ_B at 300 K is in agreement with an f"2 configuration of U"4"+. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Assessing Hubbard-corrected AM05+U and PBEsol+U density functionals for strongly correlated oxides CeO_2 and Ce_2O_3

International Nuclear Information System (INIS)

Weck, Philippe F.; Kim, Eunja

2016-01-01

The structure–property relationships of bulk CeO_2 and Ce_2O_3 have been investigated using AM05 and PBEsol exchange–correlation functionals within the frameworks of Hubbard-corrected density functional theory (DFT+U) and density functional perturbation theory (DFPT+U). Compared with conventional PBE+U, RPBE+U, PW91+U and LDA+U functionals, AM05+U and PBEsol+U describe experimental crystalline parameters and properties of CeO_2 and Ce_2O_3 with superior accuracy, especially when +U is chosen close to its value derived by the linear-response approach. Lastly, the present findings call for a reexamination of some of the problematic oxide materials featuring strong f- and d-electron correlation using AM05+U and PBEsol+U.

SU(5) x U(1) phenomenology: Theorems on neutral-current analysis

International Nuclear Information System (INIS)

Zee, A.; Kim, J.E.

1980-01-01

We embed the SU(5) unified theory of Georgi and Glashow in a U(5) theory. This may result from the breaking of an SU(N), N>5, theory or of a GL(5,c) theory. At low energy this leads to an SU(2) x U(1) x U(1) electroweak theory. We show that, with a suitable choice of Higgs representations, the predictions of this theory for neutral-current experiments are characterized by three parameters. For appropriate values of these parameters, the predictions are practically indistinguishable from the standard SU(2) x U(1) theory. Certain theorems on the analysis of neutral-current interactions are proved. (Section V is independent for readers who are interested only in the theorems.) More accurate neutral-current measurement might answer the question of whether SU(5) x U(1) is relevant. Possible verification of the present electroweak theory can result from (roughly) an order suppression relative to the standard prediction on the asymmetries in e + e - → μ + μ - and discovery of two Z bosons around 90 --100 GeV. GL(n,c) gauge theories are formulated in the Appendix

Hyperpolarized [U-(2) H, U-(13) C]Glucose reports on glycolytic and pentose phosphate pathway activity in EL4 tumors and glycolytic activity in yeast cells.

Science.gov (United States)

Timm, Kerstin N; Hartl, Johannes; Keller, Markus A; Hu, De-En; Kettunen, Mikko I; Rodrigues, Tiago B; Ralser, Markus; Brindle, Kevin M

2015-12-01

A resonance at ∼181 ppm in the (13) C spectra of tumors injected with hyperpolarized [U-(2) H, U-(13) C]glucose was assigned to 6-phosphogluconate (6PG), as in previous studies in yeast, whereas in breast cancer cells in vitro this resonance was assigned to 3-phosphoglycerate (3PG). These peak assignments were investigated here using measurements of 6PG and 3PG (13) C-labeling using liquid chromatography tandem mass spectrometry (LC-MS/MS) METHODS: Tumor-bearing mice were injected with (13) C6 glucose and the (13) C-labeled and total 6PG and 3PG concentrations measured. (13) C MR spectra of glucose-6-phosphate dehydrogenase deficient (zwf1Δ) and wild-type yeast were acquired following addition of hyperpolarized [U-(2) H, U-(13) C]glucose and again (13) C-labeled and total 6PG and 3PG were measured by LC-MS/MS RESULTS: Tumor (13) C-6PG was more abundant than (13) C-2PG/3PG and the resonance at ∼181 ppm matched more closely that of 6PG. (13) C MR spectra of wild-type and zwf1Δ yeast cells showed a resonance at ∼181 ppm after labeling with hyperpolarized [U-(2) H, U-(13) C]glucose, however, there was no 6PG in zwf1Δ cells. In the wild-type cells 3PG was approximately four-fold more abundant than 6PG CONCLUSION: The resonance at ∼181 ppm in (13) C MR spectra following injection of hyperpolarized [U-(2) H, U-(13) C]glucose originates predominantly from 6PG in EL4 tumors and 3PG in yeast cells. © 2014 Wiley Periodicals, Inc.

U-Shaped Interest in U-Shaped Development--and What It Means

Science.gov (United States)

Siegler, Robert S.

2004-01-01

Interest in U-shaped development has itself undergone a U-shaped progression. Twenty-five years ago, interest in U-shaped development was high. This interest was evident at a 1978 conference in Tel Aviv on "U-shaped Behavioral Growth" that resulted in the publication of a book of the same title 4 years later (Strauss, 1982). The breadth…

Dicty_cDB: Contig-U14400-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U14400-1 no gap 1939 4 4053811 4055750 PLUS 5 7 U14400 0 0 2 0 0 1 0 0 1 1 0 0 0 0 Show Contig...-U14400-1 Contig ID Contig-U14400-1 Contig update 2002.12.18 Contig sequence >Contig-U14400-1 (Contig...-U14400-1Q) /CSM_Contig/Contig-U14400-1Q.Seq.d CATTACCAATAAATTTATCTGCTTCAACACCTATACCAATGACATCACCA...AGGTTTATAAAATATATTGAATCAATTTTTGATTAAA Gap no gap Contig length 1939 Chromosome number (1..6, M) 4 Chromosome...HQQQQSKTVTSSTTSTETTTTVESSTTSTTITTSTSTPIPTTITTTPTTPI NSDNSWTFTSFSPKVFKEIRRYYGVDEEFLKSQENSSGIVKFLEVQTIGRSGSFFY

Seawater 234U/238U recorded by modern and fossil corals

Science.gov (United States)

Chutcharavan, Peter M.; Dutton, Andrea; Ellwood, Michael J.

2018-03-01

U-series dating of corals is a crucial tool for generating absolute chronologies of Late Quaternary sea-level change and calibrating the radiocarbon timescale. Unfortunately, coralline aragonite is susceptible to post-depositional alteration of its primary geochemistry. One screening technique used to identify unaltered corals relies on the back-calculation of initial 234U/238U activity (δ234Ui) at the time of coral growth and implicitly assumes that seawater δ234U has remained constant during the Late Quaternary. Here, we test this assumption using the most comprehensive compilation to date of coral U-series measurements. Unlike previous compilations, this study normalizes U-series measurements to the same decay constants and corrects for offsets in interlaboratory calibrations, thus reducing systematic biases between reported δ234U values. Using this approach, we reassess (a) the value of modern seawater δ234U, and (b) the evolution of seawater δ234U over the last deglaciation. Modern coral δ234U values (145.0 ± 1.5‰) agree with previous measurements of seawater and modern corals only once the data have been normalized. Additionally, fossil corals in the surface ocean display δ234Ui values that are ∼5-7‰ lower during the last glacial maximum regardless of site, taxon, or diagenetic setting. We conclude that physical weathering of U-bearing minerals exposed during ice sheet retreat drives the increase in δ234U observed in the oceans, a mechanism that is consistent with the interpretation of the seawater Pb-isotope signal over the same timescale.

A single methyltransferase YefA (RlmCD) catalyses both m5U747 and m5U1939 modifications in Bacillus subtilis 23S rRNA

DEFF Research Database (Denmark)

Desmolaize, Benoit; Fabret, Céline; Brégeon, Damien

2011-01-01

Escherichia coli possesses three paralogues. These comprise the methyltransferases TrmA that targets U54 in tRNAs, RlmC that modifies U747 in 23S rRNA and RlmD that is specific for U1939 in 23S rRNA. The tRNAs and rRNAs of the Gram-positive bacterium Bacillus subtilis have the same three m(5)U modifications....... However, as previously shown, the m(5)U54 modification in B. subtilis tRNAs is catalysed in a fundamentally different manner by the folate-dependent enzyme TrmFO, which is unrelated to the E. coli TrmA. Here, we show that methylation of U747 and U1939 in B. subtilis rRNA is catalysed by a single enzyme...

A mixed-valent uranium phosphonate framework containing U{sup IV}, U{sup V}, and U{sup VI}

Energy Technology Data Exchange (ETDEWEB)

Chen, Lanhua; Zheng, Tao; Wang, Yaxing; Diwu, Juan; Chai, Zhifang; Wang, Shuao [School for Radiological and interdisciplinary Sciences (RAD-X), Soochow University, Suzhou (China); Collaborative Innovation Center of Radiation Medicine, Jiangsu Higher Education Institutions, Suzhou (China); Bao, Songsong; Zheng, Limin [State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University (China); Zhang, Linjuan; Wang, Jianqiang [Shanghai Institute of Applied Physics and, Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai (China); Liu, Hsin-Kuan [Department of Chemistry, National Central University, Jhongli (China); Albrecht-Schmitt, Thomas E. [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL (United States)

2016-08-16

It is shown that U{sup V}O{sub 2}{sup +} ions can reside at U{sup VI}O{sub 2}{sup 2+} lattice sites during mild reduction and crystallization process under solvothermal conditions, yielding a complicated and rare mixed-valent uranium phosphonate compound that simultaneously contains U{sup IV}, U{sup V}, and U{sup VI}. The presence of uranium with three oxidation states was confirmed by various characterization techniques, including X-ray crystallography, X-ray photoelectron, electron paramagnetic resonance, FTIR, UV/Vis-NIR absorption, and synchrotron radiation X-ray absorption spectroscopy, and magnetism measurements. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Baryon number generation in a flipped SU(5) x U(1) model

International Nuclear Information System (INIS)

Campbell, B.; Hagelin, J.; Nanopoulos, D.V.; Olive, K.A.

1988-01-01

We consider the possibilities for generating a baryon asymmetry in the early universe in a flipped SU(5) x U(1) model inspired by the superstring. Depending on the temperature of the radiation background after inflation we can distinguish between two scenarios for baryogenesis: (1) After reheating the original SU(5) x U(1) symmetry is restored, or there was no inflation at all; (2) reheating after inflation is rather weak and SU(5) x U(1) is broken. In either case the asymmetry is generated by the out-of-equilibrium decays of a massive SU(3) x SU(2) x U(1) singlet field φ m . In the flipped SU(5) x U(1) model, gauge symmetry breaking is triggered by strong coupling phenomena, and is in general accompanied by the production of entropy. We examine constraints on the reheating temperature and the strong coupling scale in each of the scenarios. (orig.)

U.S. Korean Youth's Ideas and Experience of U.S. Education, U.S. Society, and U.S. History

Science.gov (United States)

An, Sohyun

2009-01-01

Drawing on and conversing with the large body of research and literature on young people's historical understanding, Asian American education, transnational migration, and Korean American studies, this dissertation research explored contemporary U.S. Korean youth's ideas and experiences of U.S. education, U.S. society and U.S. history.…

Dicty_cDB: Contig-U09640-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U09640-1 gap included 1368 2 219988 218635 MINUS 4 5 U09640 0 0 2 0 0 0 0 0 0 0 0 0 1 1 Show Contig...-U09640-1 Contig ID Contig-U09640-1 Contig update 2002. 9.13 Contig sequence >Contig-U09640-1 (Contig...-U09640-1Q) /CSM_Contig/Contig-U09640-1Q.Seq.d ACTGTTGGCCTACTGGNAAAAAATAGTGTAATAATAACCAACAAT...AACAACAACAACAAAAACAAAAACAAATTTTAATT AAATAAAATAATAATATAAAATATAATA Gap gap included Contig...ate 2004. 6.10 Homology vs CSM-cDNA Query= Contig-U09640-1 (Contig-U09640-1Q) /CSM_Contig/Contig

Primary and secondary structure of U8 small nuclear RNA

International Nuclear Information System (INIS)

Reddy, R.; Henning, D.; Busch, H.

1985-01-01

U8 small nuclear RNA is a new, capped, 140 nucleotides long RNA species found in Novikoff hepatoma cells. Its sequence is: m3GpppAmUmCGUCAGGA GGUUAAUCCU UACCUGUCCC UCCUUUCGGA GGGCAGAUAG AAAAUGAUGA UUGGAGCUUG CAUGAUCUGC UGAUUAUAGC AUUUCCGUGU AAUCAGGACC UGACAACAUC CUGAUUGCUU CUAUCUGAUUOH. This RNA is present in approximately 25,000 copies/cell, and it is enriched in nucleolar preparations. Like U1, U2, U4/U6, and U5 RNAs, U8 RNA was also present as a ribonucleoprotein associated with the Sm antigen. The rat U8 RNA was highly homologous (greater than 90%) to a recently characterized 5.4 S RNA from mouse cells infected with spleen focus-forming virus. In addition to the U8 RNA, three other U small nuclear RNAs were found in anti-Sm antibody immunoprecipitates from labeled rat and HeLa cells. Each of these contained a m3GpppAm cap structure; their apparent chain lengths were 60, 130, and 65 nucleotides. These U small nuclear RNAs are designated U7, U9, and U10 RNAs, respectively

Solid state reactions of MoO3 and Na2MoO4 with (U.85,Ce.15)O2x

International Nuclear Information System (INIS)

Dahale, N.D.; Keskar, Meera; Singh Mudher, K.D.; Chawla, K.L.

1999-01-01

(U .85 ,Ce .15 )MoO 6-x was prepared by the solid state reactions of (U .85 ,Ce .15 )O 2±x with MoO 3 in air at 600 deg C. Solid state reactions of Na 2 MoO 4 with (U .85 ,Ce .15 )MoO 6.x up to 550 deg C in air led to the formation of Na 2 (U .85 ,Ce .15 )Mo 2 O 10-x and Na 2 (U .85 , Ce .15 ) 2 Mo 3 O 16-x . These compounds were characterised by x-ray and thermal methods. The x-ray powder data of (U .85 , Ce .15 ) MoO 6-x were indexed on monoclinic system whereas, data of Na 2 (U .85 ,Ce .15 ) Mo 2 O 10-x and Na 2 (U .85 ,Ce .15 ) 2 Mo 3 O 16-x were indexed on orthorhombic and monoclinic system respectively. (author)

Grain Size and Phase Purity Characterization of U3Si2 Pellet Fuel

Energy Technology Data Exchange (ETDEWEB)

Hoggan, Rita E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tolman, Kevin R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cappia, Fabiola [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wagner, Adrian R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason M. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2018-05-01

Characterization of U3Si2 fresh fuel pellets is important for quality assurance and validation of the finished product. Grain size measurement methods, phase identification methods using scanning electron microscopes equipped with energy dispersive spectroscopy and x-ray diffraction, and phase quantification methods via image analysis have been developed and implemented on U3Si2 pellet samples. A wide variety of samples have been characterized including representative pellets from an initial irradiation experiment, and samples produced using optimized methods to enhance phase purity from an extended fabrication effort. The average grain size for initial pellets was between 16 and 18 µm. The typical average grain size for pellets from the extended fabrication was between 20 and 30 µm with some samples exhibiting irregular grain growth. Pellets from the latter half of extended fabrication had a bimodal grain size distribution consisting of coarsened grains (>80 µm) surrounded by the typical (20-30 µm) grain structure around the surface. Phases identified in initial uranium silicide pellets included: U3Si2 as the main phase composing about 80 vol. %, Si rich phases (USi and U5Si4) composing about 13 vol. %, and UO2 composing about 5 vol. %. Initial batches from the extended U3Si2 pellet fabrication had similar phases and phase quantities. The latter half of the extended fabrication pellet batches did not contain Si rich phases, and had between 1-5% UO2: achieving U3Si2 phase purity between 95 vol. % and 98 vol. % U3Si2. The amount of UO2 in sintered U3Si2 pellets is correlated to the length of time between U3Si2 powder fabrication and pellet formation. These measurements provide information necessary to optimize fabrication efforts and a baseline for future work on this fuel compound.

Dicty_cDB: Contig-U01997-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U01997-1 gap included 886 2 1683026 1682230 MINUS 3 4 U01997 1 0 0 0 0 0 2 0 0 0 0 0 0 0 Show Contig...-U01997-1 Contig ID Contig-U01997-1 Contig update 2001. 8.29 Contig sequence >Contig-U01997-1 (Contig-U01997-1Q) /CSM_Contig/Contig-U01997...ATTGAAATAATATTTATTTATTTTTTTAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA Gap gap included Contig...nfkvfgieiifiyffkkkkkkkkkkkkkkkkkkk own update 2004. 6. 9 Homology vs CSM-cDNA Query= Contig-U01997-1 (Contig-U01997-1Q) /CSM_Contig.../Contig-U01997-1Q.Seq.d (896 letters) Database: CSM 6905 sequences; 5,674,871 total l

An Empirical Comparison of the EQ-5D-5L, DEMQOL-U and DEMQOL-Proxy-U in a Post-Hospitalisation Population of Frail Older People Living in Residential Aged Care.

Science.gov (United States)

Ratcliffe, Julie; Flint, Thomas; Easton, Tiffany; Killington, Maggie; Cameron, Ian; Davies, Owen; Whitehead, Craig; Kurrle, Susan; Miller, Michelle; Liu, Enwu; Crotty, Maria

2017-06-01

To empirically compare the measurement properties of the DEMQOL-U and DEMQOL-Proxy-U instruments to the EQ-5D-5L and its proxy version (CEQ-5D-5L) in a population of frail older people living in residential aged care in the post-hospitalisation period following a hip fracture. A battery of instruments to measure health-related quality of life (HRQoL), cognition, and clinical indicators of depression, pain and functioning were administered at baseline and repeated at 4 weeks' follow-up. Descriptive summary statistics were produced and psychometric analyses were conducted to assess the levels of agreement, convergent validity and known group validity between clinical indicators and HRQoL measures. There was a large divergence in mean (SD) utility scores at baseline for the EQ-5D-5L and DEMQOL-U [EQ-5D-5L mean 0.21 (0.19); DEMQOL-U mean 0.79 (0.14)]. At 4 weeks' follow-up, there was a marked improvement in EQ-5D-5L scores whereas DEMQOL-U scores had deteriorated. [EQ-5D-5L mean 0.45 (0.38); DEMQOL-U mean 0.58 (0.38)]. The EQ-5D and CEQ-5D-5L were more responsive to the physical recovery trajectory experienced by frail older people following surgery to repair a fractured hip, whereas the DEMQOL-U and DEMQOL-Proxy-U appeared more responsive to the changes in delirium and dementia symptoms often experienced by frail older people in this period. This study presents important insights into the HRQoL of a relatively under-researched population of post-hospitalisation frail older people in residential care. Further research should investigate the implications for economic evaluation of self-complete versus proxy assessment of HRQoL and the choice of preference-based instrument for the measurement and valuation of HRQoL in older people exhibiting cognitive decline, dementia and other co-morbidities.

The Recovery of Uranium From The Rejected Fuel Plate Dispersion Type of U3O8-Al and U3Si2Al by NaOH

International Nuclear Information System (INIS)

Widodo, G; Aji, D

1998-01-01

The recovery of uranium from the rejected fuel plate dispersion type of U 3 O 8 -AI And U 3 Si 2 -AI with a dissolution has been performed.Each of 5 fragment of fuel plate dispersion of U 3 O 8 -AI or U 3 Si 2 Al of 1x4 cm size was put in the distilled glass content of 250 ml NaOH solution whit The concentration variation 10,15,20,25,and 30%,and than was heated at temperature of 102 o C and was stirred constantly by magnetic stirred.Uranium in the form of U 3 O 8 or U 3 Si 2 was separated by filtration and Either residu and filtrate was analyzed by potentiometry using modified Devies Gray method. From the experiment data it was found in the residu that presentation of uranium was 83.99-84.05% and 84.67-86.556% while in filtrate it was found 53.90 ppm and 69.3 ppm

The calculation of the contributions to low energy e+H2 scattering from sigma u+ and pion u symmetries using the Kohn variational method

International Nuclear Information System (INIS)

Armour, E.A.G.; Baker, D.J.; Plummer, M.

1990-01-01

Above incident energies of about 2 eV, the contribution to the total cross section in positron+H2 scattering from the sigma g+ symmetry is insufficient to account for the experimental value. Calculations carried out of the lowest partial waves of sigma u+ symmetry and Pion u symmetry using the Kohn variational method are described. The contributions to the total cross section from the two equivalent partial waves of Pion u symmetry significantly reduce the discrepancy with experiment up to incident energies of 4 to 5 eV. Comparisons are made with recent R-matrix calculations performed by Danby and Tennyson

The calculation of the contributions to low energy e+H2 scattering from sigma u+ and Pion u symmetries using the Kohn variational method

Science.gov (United States)

Armour, E. A. G.; Baker, D. J.; Plummer, M.

1990-01-01

Above incident energies of about 2 eV, the contribution to the total cross section in positron+H2 scattering from the sigma g+ symmetry is insufficient to account for the experimental value. Calculations carried out of the lowest partial waves of sigma u+ symmetry and Pion u symmetry using the Kohn variational method are described. The contributions to the total cross section from the two equivalent partial waves of Pion u symmetry significantly reduce the discrepancy with experiment up to incident energies of 4 to 5 eV. Comparisons are made with recent R-matrix calculations performed by Danby and Tennyson.

Characterization of the interaction layer in diffusion couples U-Mo-Zr/Al and U-Mo-Zr/Al-A356 at 550 C degrees; Caracterizacion de la zona de interaccion en pares de difusion a 550 grados C U-Mo-Zr/Al y U-Mo-Zr/Al-A356

Energy Technology Data Exchange (ETDEWEB)

Komar Varela, Carolina; Arico, Sergio; Mirandou, Marcela; Balart, Silvia; Gribaudo, Luis [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Materiales; com, carolinakomar@gmail

2007-07-01

Out-of-pile diffusion experiments were performed between U-7 wt.% Mo-1 wt.% Zr and Al or Al A356 (7,1 wt.% Si) at 550 C degrees. In this work morphological characterization and phase identification on both interaction layers are presented. They were carried out by the use of different techniques: optical and scanning electron microscopy, X-ray diffraction and WDS microanalysis. In the interaction layer U-7 wt.% Mo-1 wt.% Zr/Al, the phases UAl{sub 3}, UAl{sub 4}, Al{sub 20}Mo{sub 2}U and Al{sub 43}Mo{sub 4}U{sub 6} were identified. Similar results in the interaction layer of the U-7 % Mo/Al at 580 C degrees were previously obtained. In the interaction layer U-7 wt.% Mo-1 wt.% Zr/Al A356, the phases U(Al,Si){sub 3} with 25 at.% Si and Si{sub 5}U{sub 3} were identified. This last phase, with a higher Si concentration, was identified with X-ray diffraction synchrotron radiation performed at the National Synchrotron Light Laboratory, Campinas, Brazil. (author) [Spanish] Se realizaron experiencias fuera de reactor en pares de difusion quimica U-7 % Mo-1 % Zr/Al y U-7 % Mo-1 % Zr/Al A356. En este trabajo se presentan los resultados de la caracterizacion morfologica e identificacion de fases presentes en la zona de interaccion que se forma al ser sometidos a un tratamiento isotermico de 1,5 h a 550 grados C. Las tecnicas utilizadas fueron: microscopia optica y electronica de barrido, difraccion de rayos X y microanalisis cuantitativo por sonda electronica. En la zona de interaccion correspondiente al par U-7 % Mo-1 % Zr/Al se identificaron las fases UAl{sub 3}, UAl{sub 4}, Al{sub 20}Mo{sub 2}U y Al{sub 43}Mo{sub 4}U{sub 6}. Estas cuatro fases fueron identificadas en pares U-7 % Mo/Al a 580 grados C en trabajos anteriores. En la zona de interaccion correspondiente al par U-7 % Mo-1 % Zr/Al A356 se identificaron las fases U(Al,Si){sub 3} (con una concentracion de 25 %at.Si) y Si{sub 5}U{sub 3}. Este compuesto rico en Si solo pudo ser identificado mediante la utilizacion de

Development and evaluation of a collection apparatus for recoil products for study of the deexcitation process of "2"3"5"mU

International Nuclear Information System (INIS)

Shigekawa, Y.; Kasamatsu, Y.; Shinohara, A.

2016-01-01

The nucleus "2"3"5"mU 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 "2"3"5"mU depends on its chemical environment. We plan to study the deexcitation process of "2"3"5"mU 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 "2"3"5"mU samples from "2"3"9Pu 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 "2"2"4Ra recoiling out of "2"2"8Th electrodeposited and precipitated sources. The pressure in the apparatus (vacuum or 1 atm of N_2 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 "2"2"8Th sources. From these results, the suitable conditions of the "2"3"9Pu sources for preparation of "2"3"5"mU were determined. In addition, dissolution efficiencies were determined by washing collected "2"2"4Ra with solutions. When "2"2"4Ra was collected in 1 atm of N_2 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 "2"3"5"mU samples for various chemical forms.

Preparation and certification of a uranium isotope certified reference material JAERI-U5

International Nuclear Information System (INIS)

Tamura, Shuzo; Hashitani, Hiroshi

1982-06-01

The Committee on Analytical Chemistry of Nuclear Fuels and Reactor Materials, JAERI had planned to prepare a new reference material, JAERI-U5 for uranium isotopic measurement since 1978. The reference material is composed of 6 samples of different enrichment in the range of 0.2 to 4.5 wt. percents of 235 U. The preparation includes dissolution of raw materials, blending of solutions, precipitation of ammonium diuranate, drying and ignition to U 3 O 8 . A mass-spectrometric collaborative analysis was carried out by well-trained two laboratories in this country, JAERI and PNC. The certified values were decided from the result of the collaborative work. As the measurements were based on NBS SRM's, JAERI-U5 should be called tertiary standard. The materials are packed in bottles of low-potassium-content glass for a possible use in non-destructive gamma-rays spectrometry. The reference material has been distributing from JAERI with a price of yen 140,000 per set (6 samples of 2 g of each) since 1979. (author)

Reduction of UF4 to U-metal

International Nuclear Information System (INIS)

Namkung, H.; Min, B.T.; Kim, J.S.; Whang, S.C.

1982-01-01

In the second years of study for the production of the metallic uranium with reactors which can produce 1 Kg and 4 Kg U-metal, various factors on the yield of U-metal and the leaching condition for uranium recovery with nitric acid are examined. The jolter has been used for the charging with liner (MgF 2 ) while the hand-tamping method for the filling of reaction mixtures (UF 4 -Mg) in the reactor, and their average densities are 1.23g/cc and 2.90g/cc, respectively. The various effects on the yield such as magnesium excess, furnace control temperatue, charge densities of liner and reaction mixtures, have been studied but the yields of crude metal production are in the wide range from 93 % down to about 65 %. Generally, six percent magnesium excess produced higher yields than did either 2 or 10 percent excess. The leaching condition for the uranium recovery from slag are also investigated with dilute nitric acid (3-6N) as well as higher concentrated nitric acid (9.5N) but the leaching yields are same in either solution. Uranium recovery from the slag is very effective with dilute nitric acid (3N) leaching for less than one hour at 60degC. (Author)

A gravimetric and an X-ray fluorescence method for the determination of rubidium in Rb2U(SO4)3

International Nuclear Information System (INIS)

Mudher, K.D.S.; Krishnan, K.; Jayadevan, N.C.

1993-01-01

Chemical characterization of rubidium uranium(IV) trisulfate, RB 2 U(SO 4 ) 3 , a new chemical assay standard for uranium requires accurate analysis of rubidium. A gravimetric and an X-ray fluorescence method (XRF) for the determination of rubidium in this compound are described. In the gravimetric method, rubidium is determined as Rb 2 Na[Co(NO 2 ) 6 ].H 2 O without separating uranium with a precision of the order of ±0.5%. In the XRF method, the concentration ratio of rubidium to uranium, C Rb /C U , is determined in the solid samples by the binary ratio method using calibration between intensity ratios (I Rb /I U ) and concentration ratios (C Rb /C U ). (author) 6 refs.; 2 figs.; 3 tabs

Assessment of the concentrations of U and Th in PM2.5 from Mexico City and their potential human health risk

International Nuclear Information System (INIS)

Mendez-Garcia, Carmen Grisel; Solis-Rosales, Corina; Rafael Chavez-Lomeli, Efrain

2017-01-01

This is one of the first studies in small particulate matter (PM 2.5 ) by inductively coupled plasma sector field mass spectrometry to measure the activity concentrations of isotopic uranium ( 234 , 235 and 238 U) and thorium ( 232 Th) in these fine particulates, to know their origin and their impact on human health in Mexico City. A different isotopic composition from the natural uranium composition was found. The 235 U/ 238 U atom ratio values are considered as low enrichment uranium, around 2% of 235 U enrichment. Both 235 U/ 238 U and 234 U/ 238 U ratios suggested anthropological rather natural source is impacting the composition of uranium in PM 2.5 . (author)

Walls of massive K\\"ahler sigma models on SO(2N)/U(N) and Sp(N)/U(N)

OpenAIRE

Arai, Masato; Shin, Sunyoung

2011-01-01

We study the Bogomol'nyi-Prasad-Sommerfield wall solutions in massive K\\"ahler nonlinear sigma models on SO(2N)/U(N) and Sp(N)/U(N) in three-dimensional spacetime. We show that SO(2N)/U(N) and Sp(N)/U(N) models have 2^{N-1} and 2^N discrete vacua, respectively. We explicitly construct the exact BPS multiwall solutions for N\\le 3.

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

Science.gov (United States)

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(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.

Dicty_cDB: Contig-U12073-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U12073-1 gap included 912 2 2118980 2119867 PLUS 4 5 U12073 0 0 0 2 0 0 0 1 0 1 0 0 0 0 Show Contig...-U12073-1 Contig ID Contig-U12073-1 Contig update 2002.12.18 Contig sequence >Contig-U12073-1 (Contig...-U12073-1Q) /CSM_Contig/Contig-U12073-1Q.Seq.d CTGTTGGCCTACTGGNAATTGAAACAATTGTTTCAGCAAATATTA...AAGA Gap gap included Contig length 912 Chromosome number (1..6, M) 2 Chromosome length 8467578 Start point ...GPXSXDY*r own update 2004. 6.10 Homology vs CSM-cDNA Query= Contig-U12073-1 (Contig-U12073-1Q) /CSM_Contig/Contig

Dicty_cDB: Contig-U15573-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U15573-1 gap included 2005 4 5020093 5018210 MINUS 13 13 U15573 0 5 0 1 1 0 ...0 0 0 1 1 0 2 2 Show Contig-U15573-1 Contig ID Contig-U15573-1 Contig update 2004. 6.11 Contig sequence >Contig-U15573-1 (Contig...-U15573-1Q) /CSM_Contig/Contig-U15573-1Q.Seq.d AGTCTTGAGCTTTTATTGGGTCAACCATTGGGTGAATATAC... AGCNTTAACNGGNAA Gap gap included Contig length 2005 Chromosome number (1..6, M) ...xxlfrsnxslxxxxxxsxnxx Frame C: s*afigstig*iyiylkrfhlfl*skryyqskw*fkifpilkqttiiyen

Solubility Determination of Uranium (IV) Oxalates U(C2O4)2.6H2O and M2U2(C2O4)5.nH2O (M = mono-charged cation)

International Nuclear Information System (INIS)

Costenoble, Sylvain; Grandjean, Stephane; Arab-Chapelet, Benedicte; Abraham, Francis

2008-01-01

The solubility of uranium (IV) oxalate compounds was studied in order to have a precise insight of the behaviour of An(IV)-An(III) (An(IV) = U, Np or Pu and An(III) = Pu or Am) mixed oxalate in the context of oxalic co-conversion for actinide co-management. Concepts of thermodynamics of aqueous-solid solution are reviewed by introducing LIPPMANN theory and THORSTENSON and PLUMMER 'stoichiometric saturation' model in a way to understand and model the system of interest. Different analytical techniques have been developed in order to titrate uranium and/or other actinides at trace levels in solution. This thorough investigation is the basis of further experiments on the solubility of mixed U(IV)- An(III) oxalate solid solutions as a function of the nature of the trivalent actinide and the An(III)/U(IV) ratio. (authors)

Introduction: U.S. Homophile Internationalism.

Science.gov (United States)

Stein, Marc

2017-01-01

This article introduces "U.S. Homophile Internationalism," a special issue of the Journal of Homosexuality. The introduction provides a broad overview of the "U.S. Homophile Internationalism" archive and exhibit, which was published on the Outhistory Web site in 2015. The archive and exhibit consists of more than 800 U.S. homophile magazine articles, letters, and other items that referenced non-U.S. regions of the world from 1953 to 1964. The essays in the special issue focus on (1) Africa; (2) Asia and the Pacific; (3) Canada; (4) Latin America and the Caribbean; (5) the Middle East; and (6) Russia, the Soviet Union, and Eastern Europe. There is also an article that addresses the public history and digital humanities dimensions of the project. The introduction concludes by discussing the essays' common goals, themes, and concerns.

Supersymmetric U boson and the old U(1) problem

International Nuclear Information System (INIS)

Kim, B.R.

1983-01-01

In the supersymmetric SU(3)xSU(2)xU(1)xUsup(')(1) model the new gauge group Usup(')(1) enforces the introduction of mirror fermions. In this note we address the inverse question. If one starts with SU(3)xSU(2)xU(1) including mirror fermions, what physical arguments other than the supersymmetric require the introduction of a new gauge group Usup(')(1). It turns out that the old U(1) problem is closely related with this question. Further we give an estimate for the upper bound for the parameter of the supersymmetric U boson r and x. (orig.)

Methyl isobutyl ketone exposure-related increases in specific measures of α2u-globulin (α2u) nephropathy in male rats along with in vitro evidence of reversible protein binding

International Nuclear Information System (INIS)

Borghoff, S.J.; Poet, T.S.; Green, S.; Davis, J.; Hughes, B.; Mensing, T.; Sarang, S.S.; Lynch, A.M.; Hard, G.C.

2015-01-01

Chronic exposure to methyl isobutyl ketone (MIBK) resulted in an increase in the incidence of renal tubule adenomas and occurrence of renal tubule carcinomas in male, but not female Fischer 344 rats. Since a number of chemicals have been shown to cause male rat renal tumors through the α2u nephropathy-mediated mode of action, the objective of this study is to evaluate the ability of MIBK to induce measures of α2u nephropathy including renal cell proliferation in male and female F344 rats following exposure to the same inhalation concentrations used in the National Toxicology Program (NTP) cancer bioassay (0, 450, 900, or 1800 ppm). Rats were exposed 6 h/day for 1 or 4 weeks and kidneys excised approximately 18 h post exposure to evaluate hyaline droplet accumulation (HDA), α2u staining of hyaline droplets, renal cell proliferation, and to quantitate renal α2u concentration. There was an exposure-related increase in all measures of α2u nephropathy in male, but not female rat kidneys. The hyaline droplets present in male rat kidney stained positively for α2u. The changes in HDA and α2u concentration were comparable to D-limonene, an acknowledged inducer of α2u nephropathy. In a separate in vitro study using a two-compartment vial equilibration model to assess the interaction between MIBK and α2u, the dissociation constant (K d ) was estimated to be 1.27 × 10 −5 M. This K d is within the range of other chemicals known to bind to α2u and cause nephropathy. Together, the exposure-related increase in measures of α2u nephropathy, sustained increase in renal cell proliferation along with an indication of reversible binding of MIBK to α2u, support the inclusion of MIBK in the category of chemicals exerting renal effects through a protein droplet α2u nephropathy-mediated mode of action (MoA)

U(IV) chalcogenolates synthesized via oxidation of uranium metal by dichalcogenides.

Science.gov (United States)

Gaunt, Andrew J; Scott, Brian L; Neu, Mary P

2006-09-04

Treatment of uranium metal with dichalcogenides in the presence of a catalytic amount of iodine in pyridine affords molecular U(IV) chalcogenolates that do not require stabilizing ancillary ligands. Oxidation of U(0) by PhEEPh yields monomeric seven-coordinate U(EPh)4(py)3 (E = S(1), Se(2)). The dimeric eight-coordinate complexes [U(EPh)2(mu2-EPh)2(CH3CN)2]2 (E = S(3), Se(4)) are obtained by crystallization from solutions of 1 and 2 dissolved in acetonitrile. Oxidation of U(0) by pySSpy and crystallization from thf yields nine-coordinate U(Spy)4(thf) (5). Incorporation of elemental selenium into the oxidation of U(0) by PhSeSePh results in the isolation of [U(py)2(SePh)(mu3-Se)(mu2-SePh)]4.4py (6), a tetrameric cluster in which each U(IV) ion is eight-coordinate and the U4Se4 core forms a distorted cube. The compounds were analyzed spectroscopically and the single-crystal X-ray structures of 1 and 3-6 were determined. The isolation of 1-6 represents six new examples of actinide chalcogenolates and allows insight into the nature of "hard" actinide ion-"soft" chalcogen donor interactions.

U Shrinivasa

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education. U Shrinivasa. Articles written in Resonance – Journal of Science Education. Volume 17 Issue 4 April 2012 pp 365-377 General Article. The Evolution of Diesel Engines · U Shrinivasa · More Details Fulltext PDF ...

A year-by-year record of 236-U/238-U in coral as a step towards establishing 236-U from nuclear weapons testing fall-out as oceanic tracer

Energy Technology Data Exchange (ETDEWEB)

Winkler, Stephan; Steier, Peter [University of Vienna, Faculty of Physics, Vienna (Austria); Carilli, Jessica [Australian Nuclear Science and Technology Organisation, Lucas Heights (Australia)

2012-07-01

Since uranium is known to behave conservatively in ocean waters, 236-U has great potential in application as oceanic tracer. 236-U (t1/2=23.4 Ma) was introduced into the oceans by atmospheric nuclear weapon testing with amount estimates ranging from 700 kg to 1500 kg. Thus a resulting initial average 236-U/238-U ratio of at least 5e-9 is expected for an oceanic mixed layer depth of 100 m. This ratio is already higher than the natural pre-nuclear background, which is expected to be at 10e-14 levels. Even the elevated ratios of global stratospheric fall-out are beyond the capabilities of ICPMS and TIMS methods. However, the exceptional sensitivity and ultra-low background for 236-U of the Vienna Environmental Research Accelerator's Accelerator Mass Spectrometry system allows us to measure down to 10-13 detection limits. We present a year-by-year record of 236-U/238-U for a Caribbean coral core covering years 1944 to 2006, thus allowing to us put constraints on the oceanic input of 236-U by atmospheric testing. Moreover modeling of the results also demonstrates the capabilities of 236-U as oceanic tracer.

Useful to Usable (U2U): Transforming climate information into usable tools to support Midwestern agricultural production

Science.gov (United States)

Prokopy, L. S.; Widhalm, M.

2014-12-01

There is a close connection between weather and climate patterns and successful agricultural production. Therefore, incorporating climate information into farm management is likely to reduce the risk of economic losses and increase profitability. While weather and climate information is becoming ever more abundant and accessible, the use of such information in the agricultural community remains limited. Useful to Usable (U2U): Transforming Climate Variability and Change Information for Cereal Crop Producers is a USDA-NIFA funded research and extension project focused on improving the use of climate information for agricultural production in the Midwestern United States by developing user-driven decision tools and training resources. The U2U team is a diverse and uniquely qualified group of climatologists, crop modelers, agronomists, and social scientists from 9 Midwestern universities and two NOAA Regional Climate Centers. Together, we strive to help producers make better long-term plans on what, when and where to plant and also how to manage crops for maximum yields and minimum environmental damage. To ensure relevance and usability of U2U products, our social science team is using a number of techniques including surveys and focus groups to integrate stakeholder interests, needs, and concerns into all aspects of U2U research. It is through this coupling of physical and social science disciplines that we strive to transform existing climate information into actionable knowledge.

Cyberinfrastructure for the collaborative development of U2U decision support tools

Directory of Open Access Journals (Sweden)

Larry L. Biehl

2017-01-01

Full Text Available This paper describes the use of cyberinfrastructure to create interactive applications as part of the Useful to Usable (U2U project. These applications transform historical climate data, knowledge, and models into decision support tools for end users such as crop farmers, university Extension educators, and other agricultural advisors. In creating a cyberinfrastructure to support the U2U project, four major challenges have been addressed: designing and developing highly usable web applications with frequent feedback, establishing a software engineering environment to support iterative development, integrating and synthesizing historical and current datasets from a variety of sources (local vs. remote, different access methods, and formats, and supporting project collaboration needs of data and document sharing, project management, and public outreach. The overall goals of the cyberinfrastructure and its architecture design are described. Methods for data retrieval and synthesis, as well as the various software components utilized are discussed. The development and integration of tools into the collaborative HUBzero framework are highlighted, including the use of HUBzero’s core features to share ideas, algorithms, and results. A highly iterative development process that includes feedback from experts and end-users to feed requirement definition, design and application updates are also examined.

Development and characterization of monolithic fuel miniplate alloy U-2.5Zr-7.5Nb, coated in zircaloy; Desenvolvimento e caracterizacao do combustivel nuclear tipo placa monolitico da liga U-2,5Zr-7,5Nb revestido em zircaloy

Energy Technology Data Exchange (ETDEWEB)

Machado, Geraldo Correa

2014-06-01

The autocthonal production of nuclear fuel in Brazil for test and research reactors is restricted to MTR (Material Test Reactor) fuel type dispersion plate, using U3Si2 alloy, coated and dispersed in aluminum, developed by IPEN-SP for use in IEA-R1 reactor. Moreover, the UO{sub 2} fuel rod type for power reactors is manufactured by Rezende (RJ) with a German technology by INB under license. Currently, Brazil is performing two programs of developing reactors. Currently, Brazil is developing two reactors. One of them is the development, by CNEN, the Brazilian Multipurpose Reactor (RMB), for testing, research and radioisotope production. The other one is the development a power reactor for naval propulsion, conducted by the Brazilian Navy. This dissertation presents the development and characterization of monolithic fuel miniplate alloy U-2.5Zr-7.5Nb, coated in zircaloy (ZRY), on a laboratory scale. Due to its innovative features and properties, this fuel can be used as fuel in both test reactors, research and producing radioisotopes for power reactors as small and medium sizes. Thus, this high potential fuel can be used in domestic reactors currently under development. The development of monolithic fuel plate type is made using the technique called 'picture-frame' where a sandwich composed of a monolith alloy U-2.5Zr- 7.5Nb coupled to a frame and coated sheets of Zry is obtained. The alloy U-2.5Zr-7.5Nb was obtained by melting in an induction furnace and then was cast into rectangular ingots of graphite, thus achieving an ingot with approximate dimensions of 170 x 50 x 60 mm. The obtained ingot was hot rolled at 850 ºC, with a 50 % reduction in thickness, in order to refine the raw structure of fusion. Samples cut from the alloy U-2.5Zr-7.5Nb, with dimensions 20 x 20 x 6 mm were placed in frames and plates Zry and joined by TIG (Tungsten Inert Gas) under an atmosphere of argon, obtaining a set of 10 mm thick, 45 mm wide and 100 mm long. The sandwiches were

The Arabidopsis splicing factors, AtU2AF65, AtU2AF35, and AtSF1 shuttle between nuclei and cytoplasms

KAUST Repository

Park, Hyo-Young

2017-04-21

The Arabidopsis splicing factors, AtU2AF65, AtU2AF35, and AtSF1 shuttle between nuclei and cytoplasms. These proteins also move rapidly and continuously in the nuclei, and their movements are affected by ATP depletion. The U2AF65 proteins are splicing factors that interact with SF1 and U2AF35 proteins to promote U2snRNP for the recognition of the pre-mRNA 3\\' splice site during early spliceosome assembly. We have determined the subcellular localization and movement of these proteins\\' Arabidopsis homologs. It was found that Arabidopsis U2AF65 homologs, AtU2AF65a, and AtU2AF65b proteins interact with AtU2AF35a and AtU2AF35b, which are Arabidopsis U2AF35 homologs. We have examined the mobility of these proteins including AtSF1 using fluorescence recovery after photobleaching and fluorescence loss in photobleaching analyses. These proteins displayed dynamic movements in nuclei and their movements were affected by ATP depletion. We have also demonstrated that these proteins shuttle between nuclei and cytoplasms, suggesting that they may also function in cytoplasm. These results indicate that such splicing factors show very similar characteristics to their human counterparts, suggesting evolutionary conservation.

The Arabidopsis splicing factors, AtU2AF65, AtU2AF35, and AtSF1 shuttle between nuclei and cytoplasms

KAUST Repository

Park, Hyo-Young; Lee, Keh Chien; Jang, Yun Hee; Kim, SoonKap; Thu, May Phyo; Lee, Jeong Hwan; Kim, Jeong-Kook

2017-01-01

The Arabidopsis splicing factors, AtU2AF65, AtU2AF35, and AtSF1 shuttle between nuclei and cytoplasms. These proteins also move rapidly and continuously in the nuclei, and their movements are affected by ATP depletion. The U2AF65 proteins are splicing factors that interact with SF1 and U2AF35 proteins to promote U2snRNP for the recognition of the pre-mRNA 3' splice site during early spliceosome assembly. We have determined the subcellular localization and movement of these proteins' Arabidopsis homologs. It was found that Arabidopsis U2AF65 homologs, AtU2AF65a, and AtU2AF65b proteins interact with AtU2AF35a and AtU2AF35b, which are Arabidopsis U2AF35 homologs. We have examined the mobility of these proteins including AtSF1 using fluorescence recovery after photobleaching and fluorescence loss in photobleaching analyses. These proteins displayed dynamic movements in nuclei and their movements were affected by ATP depletion. We have also demonstrated that these proteins shuttle between nuclei and cytoplasms, suggesting that they may also function in cytoplasm. These results indicate that such splicing factors show very similar characteristics to their human counterparts, suggesting evolutionary conservation.

U.S. - UK - Canada Trilateral Symposium

Science.gov (United States)

2009-10-02

e . 4. Procedures for intra-community arms transfers simplified. 5 Retransfer controls disco raged b t m st be. u u u complied with. Li d...IRIS – T • Airbus A310 refueller 10 FUTURE OF TRANSATLANTIC ARMAMENTS COOPERATION 1996 VISION – “I believe that national security – ours and that

Genomic organization of the rat alpha 2u-globulin gene cluster.

Science.gov (United States)

McFadyen, D A; Addison, W; Locke, J

1999-05-01

The alpha 2u-globulin are a group of similar proteins, belonging to the lipocalin superfamily of proteins, that are synthesized in a subset of secretory tissues in rats. The many alpha 2u-globulin isoforms are encoded by a multigene family that exhibits extensive homology. Despite a high degree of sequence identity, individual family members show diverse expression patterns involving complex hormonal, tissue-specific, and developmental regulation. Analysis suggests that there are approximately 20 alpha 2u-globulin genes in the rat genome. We have used fluorescence in situ hybridization (FISH) to show that the alpha 2u-globulin genes are clustered at a single site on rat Chromosome (Chr) 5 (5q22-24). Southern blots of rat genomic DNA separated by pulsed field gel electrophoresis indicated that the alpha 2u-globulin genes are contained on two NruI fragments with a total size of 880 kbp. Analysis of three P1 clones containing alpha 2u-globulin genes indicated that the alpha 2u-globulin genes are tandemly arranged in a head-to-tail fashion. The organization of the alpha 2u-globulin genes in the rat as a tandem array of single genes differs from the homologous major urinary protein genes in the mouse, which are organized as tandem arrays of divergently oriented gene pairs. The structure of these gene clusters may have consequences for the proposed function, as a pheromone transporter, for the protein products encoded by these genes.

Dicty_cDB: Contig-U12682-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U12682-1 no gap 1408 4 4961739 4963050 PLUS 47 48 U12682 0 0 0 5 0 0 2 30 0 10 0 0 0 0 Show Contig...-U12682-1 Contig ID Contig-U12682-1 Contig update 2002.12.18 Contig sequence >Contig-U12682-1 (Contig...-U12682-1Q) /CSM_Contig/Contig-U12682-1Q.Seq.d AAACACATCATCCCGTTCGATCTGATAAGTAAATCGACCTCAGGCC...ATGA AACTACTG Gap no gap Contig length 1408 Chromosome number (1..6, M) 4 Chromosome length 5430582 Start po... kwniikwysyinwykswyn**fihsiklqwsy*qcke*si*yiir*ny own update 2004. 6.10 Homology vs CSM-cDNA Query= Contig

U-isotopes and "2"2"6Ra as tracers of hydrogeochemical processes in carbonated karst aquifers from arid areas

International Nuclear Information System (INIS)

Guerrero, José Luis; Vallejos, Ángela; Cerón, Juan Carlos; Sánchez-Martos, Francisco; Pulido-Bosch, Antonio; Bolívar, Juan Pedro

2016-01-01

Sierra de Gádor is a karst macrosystem with a highly complex geometry, located in southeastern Spain. In this arid environment, the main economic activities, agriculture and tourism, are supported by water resources from the Sierra de Gádor aquifer system. The aim of this work was to study the levels and behaviour of some of the most significant natural radionuclides in order to improve the knowledge of the hydrogeochemical processes involved in this groundwater system. For this study, 28 groundwater and 7 surface water samples were collected, and the activity concentrations of the natural U-isotopes ("2"3"8U, "2"3"5U and "2"3"4U) and "2"2"6Ra by alpha spectrometry were determined. The activity concentration of "2"3"8U presented a large variation from around 1.1 to 65 mBq L"−"1. Elevated groundwater U concentrations were the result of oxidising conditions that likely promoted U dissolution. The PHREEQC modelling code showed that dissolved U mainly existed as uranyl carbonate complexes. The "2"3"4U/"2"3"8U activity ratios were higher than unity for all samples (1.1–3.8). Additionally, these ratios were in greater disequilibrium in groundwater than surface water samples, the likely result of greater water-rock contact time. "2"2"6Ra presented a wide range of activity concentrations, (0.8 up to about 4 × 10"2 mBq L"−"1); greatest concentrations were detected in the thermal area of Alhama. Most of the samples showed "2"2"6Ra/"2"3"4U activity ratios lower than unity (median = 0.3), likely the result of the greater mobility of U than Ra in the aquifer system. The natural U-isotopes concentrations were strongly correlated with dissolution of sulphate evaporites (mainly gypsum). "2"2"6Ra had a more complex behaviour, showing a strong correlation with water salinity, which was particularly evident in locations where thermal anomalies were detected. The most saline samples showed the lowest "2"3"4U/"2"3"8U activity ratios, probably due to fast uniform bulk

Interdiffusion and reaction between U and Zr

Science.gov (United States)

Park, Y.; Newell, R.; Mehta, A.; Keiser, D. D.; Sohn, Y. H.

2018-04-01

The microstructural development and diffusion kinetics were examined for the binary U vs. Zr system using solid-to-solid diffusion couples, U vs. Zr, annealed at 580 °C for 960 h, 650 °C for 480 h, 680 °C for 240 h, and 710 °C for 96 h. Scanning and transmission electron microscopies with X-ray energy dispersive spectroscopy were employed for detailed microstructural and compositional analyses. Interdiffusion and reaction in U vs. Zr diffusion couples primarily produced: δ-UZr2 solid solution (hP3) and α‧-U at 580 °C; and (γU,βZr) solid solution (cI2) and α‧-U at 650°, 680° and 710 °C. The α‧-phase was confirmed as a reduced variant of the α-U orthorhombic structure with lattice parameters, a × b × c = 2.65 × 5.40 × 4.75 (Å) with a negligible solubility for Zr at room temperature. Concentration profiles were examined to determine interdiffusion coefficients, integrated interdiffusion coefficients, and intrinsic diffusion coefficients using Boltzmann-Matano, Wagner, and Heumann analyses, respectively. Composition-dependence of interdiffusion coefficients were documented for α-U, δ-UZr2 (at 580 °C) and (γU,βZr) solid solution (at 650°, 680° and 710 °C). U was determined to intrinsically diffuse faster than Zr, approximately by an order of magnitude, in the δ-UZr2 at 580 °C, and (γU,βZr) phases at 650°, 680° and 710 °C. Based on Darken's approach, thermodynamic data available in literature were coupled to estimate the tracer diffusion coefficients and atomic mobilities of U and Zr.

9 CFR 102.5 - U.S. Veterinary Biological Product License.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false U.S. Veterinary Biological Product... BIOLOGICAL PRODUCTS § 102.5 U.S. Veterinary Biological Product License. (a) Authorization to produce each biological product shall be specified on a U.S. Veterinary Biological Product License, issued by the...

Atomization of U3Si2/U3Si for research reactor fuel

International Nuclear Information System (INIS)

Kuk, Il Hiun

2004-01-01

Instead of comminuting, U 3 Si 2 /U 3 Si powders are produced by atomizating directly from the molten alloys. Many benefits are introduced by applying the atomization technique: reduction of the process, homogeneous alloy composition within a particle and between particles, increase of the thermal conductivity and decrease of the chemical reactivity with aluminium due to particle's spherical shape. (author)

Extraction of Th and U from Swiss granites

International Nuclear Information System (INIS)

Bajo, C.

1980-12-01

The extraction, at the laboratory level, of U and Th from Swiss granites is discussed. The Mittagfluh, Bergell and Rotondo granites and the Giuv syenite offered a wide range of U and Th concentrations; 7.7 to 20.0 ppm U and 25.5 to 67.0 ppm Th. U and Th were determined in the leach solutions by the fission track method and by spectrophotometry, respectively. Samples containing less than 0.3 μg U and 4 μg Th, could be measured with an accuracy of 10% for U and 5% for Th. Leach tests were performed during which the following parameters were varied: granite-type, grain size, acid-type, acid concentration, temperature and time. There were very great leaching differences between the granites studied. Temperature was the most important parameter. Sharp differences in extraction occurred between 20 0 C, 50 0 C and 80 0 C. At 80 0 C, more than 85% U and Th were extracted. The extraction curve (percent extracted as a function of time) of aliquots sampled after 1, 2, 4, 8, 12 and 24 hours showed a plateau after 8 hours. The half life of the reaction was between one and two hours. As a general rule, Th was better extracted than U. (Auth.)

Naturally light neutrinos in the flipped SU(5)xU(1) superstring model

Energy Technology Data Exchange (ETDEWEB)

Antoniadis, I.; Rizos, J. (Centre de Physique Theorique, Ecole Polytechnique, 91 - Palaiseau (France)); Tamvakis, K. (Physics Dept., Univ. Ioannina (Greece))

1992-04-16

We analyze the SU(5)xU(1)'xU(1){sup 4}xSO(10)xSU(4) superstring model, taking into account non-renormalizable superpotential interactions up to sixth order, and find that all neutrinos stay naturally light within the experimental mass bounds. (orig.).

The fission cross sections of 230Th, 232Th, 233U, 234U, 236U, 238U, 237Np, 239Pu and 242Pu relative 235U at 14.74 MeV neutron energy

International Nuclear Information System (INIS)

Meadows, J.W.

1986-12-01

The measurement of the fission cross section ratios of nine isotopes relative to 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 235 U are: 230 Th - 0.290 +- 1.9%; 232 Th - 0.191 +- 1.9%; 233 U - 1.132 +- 0.7%; 234 U - 0.998 +- 1.0%; 236 U - 0.791 +- 1.1%; 238 U - 0.587 +- 1.1%; 237 Np - 1.060 +- 1.4%; 239 Pu - 1.152 +- 1.1%; 242 Pu - 0.967 +- 1.0%. 40 refs., 11 tabs., 9 figs

U3Si2 Fabrication and Testing for Implementation into the BISON Fuel Performance Code

Energy Technology Data Exchange (ETDEWEB)

Knight, Travis W.

2018-04-23

A creep test stand was designed and constructed for compressive creep testing of U3Si2 pellets. This is described in Chapter 3.

• Creep testing of U3Si2 pellets was completed. In total, 13 compressive creep tests of U3Si2 pellets was successfully completed. This is reported in Chapter 3.
• Secondary creep model of U3Si2 was developed and implemented in BISON. This is described in Chapter 4.
• Properties of U3Si2 were implemented in BISON. This is described in Chapter 4.
• A resonant frequency and damping analyzer (RFDA) using impulse excitation technique (IET) was setup, tested, and used to analyze U3Si2 samples to measure Young’s and Shear Moduli which were then used to calculate the Poisson ratio for U3Si2. This is described in Chapter 5.
• Characterization of U3Si2 samples was completed. Samples were prepared and analyzed by XRD, SEM, and optical microscopy. Grain size analysis was conducted on images.

Laboratory studies of 235U enrichment by chemical separation methods

International Nuclear Information System (INIS)

Daloisi, P.J.; Orlett, M.J.; Tracy, J.W.; Saraceno, A.J.

1976-01-01

Laboratory experiments on 235 U enrichment processes based on column redox ion exchange, electrodialysis, and gas exchange chromatography performed from August 1972 to September 1974 are summarized. Effluent from a 50 to 50 weight mixture of U +4 and U +6 (as UO 2 2+ ), at a total uranium concentration of 5 mg U per ml in 0.25N H 2 SO 4 -0.03N NaF solution, passing through a 100 cm length cation exchange column at 0.5 ml/min flow rates, was enriched in 235 U by 1.00090 +- .00012. The enriched fraction was mostly in the +6 valence form while the depleted fraction was U +4 retained on the resin. At flow rates of 2 ml/min, the enrichment factor decreases to 1.00033 +- .00003. In the electrodialysis experiments, the fraction of uranium diffusing through the membranes (mostly as +6 valence state) in 4.2 hours is enriched in 235 U by 1.00096 +- .00012. Gas exchange chromatography tests involved dynamic and static exposure of UF 6 over NaF. In dynamic tests, no significant change in isotopic abundance occurred in the initial one-half weight cut of UF 6 . The measured relative 235 U/ 238 U mole ratios were 1.00004 +- .00004 for these runs. In static runs, enrichment became evident. For the NaF(UF 6 )/sub x/-UF 6 system, there is 235 U depletion in the gas phase, with a single-stage factor of 1.00033 at 100 0 C and 1.00025 at 25 0 C after 10 days of equilibration. The single-stage or unit holdup time is impractically long for all three chemical processes

9 CFR 102.4 - U.S. Veterinary Biologics Establishment License.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false U.S. Veterinary Biologics... LICENSES FOR BIOLOGICAL PRODUCTS § 102.4 U.S. Veterinary Biologics Establishment License. (a) Before a U.S. Veterinary Biologics Establishment License will be issued by the Administrator for any establishment, an...

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

Science.gov (United States)

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

48 CFR 15.403-4 - Requiring certified cost or pricing data (10 U.S.C. 2306a and 41 U.S.C. 254b).

Science.gov (United States)

2010-10-01

... or pricing data (10 U.S.C. 2306a and 41 U.S.C. 254b). 15.403-4 Section 15.403-4 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 15.403-4 Requiring certified cost or pricing data (10 U.S.C. 2306a and 41 U.S.C...

Investigation of phase transformations of U2.5Zr7.5Nb and U3Zr9Nb alloys aging at 600 deg C

International Nuclear Information System (INIS)

Cantagalli, Natalia Mattar; Tanure, Leandro Paulo de Almeida Reis; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa

2009-01-01

Investigation has been made of the effects of high-temperature aging (600 deg C) on the phase transformations in the U2.5Zr7.5Nb and U3Zr9Nb alloys. These alloys have been produced with vacuum induction melting (VIM) furnace in cast ingots. The ingots were homogenized at 1000 deg C for 24 hours in vacuum of -4 torr, and cooled to room temperature at a rate of 3 deg C/min. Specimens from these homogeneous materials, cut in 3 mm high and 10 mm diameter, were reheated to γ phase at 850 deg C, for 1 hour, and aging at 600 deg C at different times from 0.5 to 24 hours. The phases decomposition were characterized by X-ray diffraction (XRD), metallographic, micro-probe analyze by energy dispersive spectrometry (EDS) and microhardness methods. It was verified that the decomposition of the δ phase proceeds in two steps. The first is a discontinuous precipitation of a lamellar two-phase aggregate composed of alpha solid solution and a metastable gamma phase. The metastable gamma phase has a constant composition at given temperature. After longer annealing, it decomposes eutectoidally into the equilibrium (α + δ 2 ) phases mixture. During this process a modification of the original lamellar microstructure takes place. The obtained metastable phases of these alloys of different compositions were analyzed in relation to their constitution, heat treatability and micrographic features and the results confronted with available distinct uranium alloys data from literature. (author)

Search for UHE emission from 4U0115+63

International Nuclear Information System (INIS)

Alexandreas, D.E.; Allen, R.C.; Biller, S.D.; Dion, G.M.; Lu, X-Q.; Vishwanath, P.R.; Yodh, G.B.; Berley, D.; Chang, C.Y.; Dingus, B.L.; Dion, C.; Goodman, J.A.; Gupta, S.K.; Haines, T.J.; Kwok, P.W.; Stark, M.J.; Burman, R.L.; Hoffman, C.M.; Lloyd-Evans, J.; Nagle, D.E.; Potter, M.E.; Sandberg, V.D.; Zhang, W.P.; Cady, D.R.; Ellsworth, R.W.; Krakauer, D.A.; Talaga, R.L.

1990-01-01

We report here the preliminary results of our observations of the sporadic x-ray binary system 4U0115 + 63. The CYGNUS air shower array has been collecting data since April 1986. No significant excess is seen from the direction of this source, nor any correlation with its 24-day orbital period. A 90% confidence-level upper limit on the flux from 4U0115 + 63 is 2.8 x 10 -13 cm -2 s -1 above 50 TeV. This flux limit is considerably lower than those reported by other UHE experiments. Search for periodicity at the neutron star frequency is in progress. 12 refs., 3 figs., 1 tab

Enzymatic U(VI) reduction by Desulfosporosinus species

International Nuclear Information System (INIS)

Suzuki, Y.; Kelly, S.D.; Kemner, K.M.; Banfield, J.F.

2004-01-01

Here we tested U(VI) reduction by a Desulfosporosinus species (sp.) isolate and type strain (DSM 765) in cell suspensions (pH 7) containing 1 mM U(VI) and lactate, under an atmosphere containing N 2 -CO 2 -H 2 (90: 5: 5). Although neither Desulfosporosinus species (spp.) reduced U(VI) in cell suspensions with 0.25% Na-bicarbonate or 0.85% NaCl, U(VI) was reduced in these solutions by a control strain, desulfovibrio desulfuricans (ATCC 642). However, both Desulfosporosinus strains reduced U(VI) in cell suspensions depleted in bicarbonate and NaCl. No U(VI) reduction was observed without lactate and H 2 electron donors or with heat-killed cells, indicating enzymatic U(VI) reduction. Uranium(VI) reduction by both strains was inhibited when 1 mM CuCl 2 was added to the cell suspensions. Because the Desulfosporosinus DSM 765 does not contain cytochrome c 3 used by Desulfovibrio spp. to reduce U(VI), Desulfosporosinus species reduce uranium via a different enzymatic pathway. (orig.)

The flipped SU(5)xU(1) string model revamped

Energy Technology Data Exchange (ETDEWEB)

Antoniadis, I.; Ellis, J.; Hagelin, J.S.; Nanopoulos, D.V. (European Organization for Nuclear Research, Geneva (Switzerland))

1989-11-02

We present a refined version of our three-generation flipped SU(5)xU(1) string model with the following properties. The complete massless spectrum is derived and shown to be free of all gauge and mixed anomalies apart from a single anomalous U(1). The imaginary part of the dilaton supermultiplet is eaten by the anomalous U(1) gauge boson, and the corresponding D-term is cancelled by large VEVs for singlet fields that break surplus U(1) gauge factors, leaving a supersymmetric vacuum with an SU(5)xU(1) visible gauge group and an SO(10)xSO(6) hidden gauge group. There are sufficient Higgs multiplets to break the visible gauge symmetry down to the standard model in an essentially unique way. All trilinear superpotential couplings have been calculated and there are in particular some giving m{sub t}, m{sub b}, m{sub tau}ne0. A renormalization group analysis shows that m{sub t}<190 GeV and m{sub b}{approx equal}3m{sub tau}. Light Higgs doublets are split automatically from heavy Higgs triplets, leaving no residual dimension-five operators for baryon decay, and the baryon lifetime tau{sub B} {approx equal} 2x10{sup 34{plus minus}2} yr. There are no tree-level flavour-changing neutral currents, but muyieldsegamma may occur at a detectable level: B(muyieldsegamma){proportional to} 10{sup -11}-10{sup -14}. (orig.).

U-Mo/Al-Si interaction: Influence of Si concentration

International Nuclear Information System (INIS)

Allenou, J.; Palancher, H.; Iltis, X.; Cornen, M.; Tougait, O.; Tucoulou, R.; Welcomme, E.; Martin, Ph.; Valot, C.; Charollais, F.; Anselmet, M.C.; Lemoine, P.

2010-01-01

Within the framework of the development of low enriched nuclear fuels for research reactors, U-Mo/Al is the most promising option that has however to be optimised. Indeed at the U-Mo/Al interfaces between U-Mo particles and the Al matrix, an interaction layer grows under irradiation inducing an unacceptable fuel swelling. Adding silicon in limited content into the Al matrix has clearly improved the in-pile fuel behaviour. This breakthrough is attributed to an U-Mo/Al-Si protective layer around U-Mo particles appeared during fuel manufacturing. In this work, the evolution of the microstructure and composition of this protective layer with increasing Si concentrations in the Al matrix has been investigated. Conclusions are based on the characterization at the micrometer scale (X-ray diffraction and energy dispersive spectroscopy) of U-Mo7/Al-Si diffusion couples obtained by thermal annealing at 450 deg. C. Two types of interaction layers have been evidenced depending on the Si content in the Al-Si alloy: the threshold value is found at about 5 wt.% but obviously evolves with temperature. It has been shown that for Si concentrations ranging from 2 to 10 wt.%, the U-Mo7/Al-Si interaction is bi-layered and the Si-rich part is located close to the Al-Si for low Si concentrations (below 5 wt.%) and close to the U-Mo for higher Si concentrations. For Si weight fraction in the Al alloy lower than 5 wt.%, the Si-rich sub-layer (close to Al-Si) consists of U(Al, Si) 3 + UMo 2 Al 20 , when the other sub-layer (close to U-Mo) is silicon free and made of UAl 3 and U 6 Mo 4 Al 43 . For Si weight concentrations above 5 wt.%, the Si-rich part becomes U 3 (Si, Al) 5 + U(Al, Si) 3 (close to U-Mo) and the other sub-layer (close to Al-Si) consists of U(Al, Si) 3 + UMo 2 Al 20 . On the basis of these results and of a literature survey, a scheme is proposed to explain the formation of different types of ILs between U-Mo and Al-Si alloys (i.e. different protective layers).

Yeast endoribonuclease stimulated by Novikoff Hepatoma small nuclear RNAS U1 and U2

International Nuclear Information System (INIS)

Stevens, A.

1982-01-01

Using [ 3 H]m 7 Gppp[ 14 C]RNA-poly(A) from yeast as a substrate, an endoribonuclease has been detected in enzyme fractions derived from a high salt wash of ribonucleoprotein particles of Saccharomyces cerevisiae. The [ 3 H]m 7 Gppp[ 14 C]RNA-poly(A) seems to be a preferred substrate since other polyribonucleotides are hydrolyzed more slowly, if at all. The enzyme is inhibited by ethidium bromide, but fully double-stranded polyribonucleotides are not hydrolyzed. The hydrolysis of [ 3 H]m 7 Gppp[ 14 C]RNA-poly(A) is stimulated about 2.5-fold by the addition of small nuclear RNAs U1 and U2 of Novikoff hepatoma cells. Results show that the stimulation involves an interaction of the labeled RNA with the small nuclear RNA

U(VI) sorption on kaolinite. Effects of pH, U(VI) concentration and oxyanions

International Nuclear Information System (INIS)

Liang Gao; Ziqian Yang; Keliang Shi; Xuefeng Wang; Zhijun Guo; Wangsuo Wu

2010-01-01

U(VI) sorption on kaolinite was studied as functions of contact time, pH, U(VI) concentration, solid-to-liquid ratio (m/V) by using a batch experimental method. The effects of sulfate and phosphate on U(VI) sorption were also investigated. It was found that the sorption kinetics of U(VI) can be described by a pseudo-second-order model. Potentiometric titrations at variable ionic strengths indicated that the titration curves of kaolinite were not sensitive to ionic strength, and that the pH of the zero net proton charge (pH PZNPC ) was at 6.9. The sorption of U(VI) on kaolinite increased with pH up to 6.5 and reached a plateau at pH >6.5. The presence of phosphate strongly increased U(VI) sorption especially at pH <5.5, which may be due to formation of ternary surface complexes involving phosphate. In contrast, the presence of sulfate did not cause any apparent effect on U(VI) sorption. A double layer model was used to interpret both results of potentiometric titrations and U(VI) sorption on kaolinite. (author)

Postirradiation examination of high-U-loaded, low-enriched U3O8, UAl2, and U3Si test fuel plates

International Nuclear Information System (INIS)

Gomez, J.; Morando, R.; Perez, E.E.; Giorsetti, D.R.; Copeland, G.L.; Hofman, G.L.; Snelgrove, J.L.

1985-01-01

The scope of this work is to present an evaluation of the postirradiation examination of the second set of high-U-loaded, low-enriched U 3 O 8 , UAl 2 and U 3 Si miniature plates manufactured by the Comision Nacional de Energia Atomica (CNEA) of Argentina, and irradiated and examined, within the framework of the Reduced Enrichment Research and Test Reactor (RERTR) Program, at Oak Ridge National Laboratory and Argonne National Laboratory. This paper includes fabrication details of the plates, their irradiation history and the results of postirradiation examination which are compared to those of the previous test and to present results from other laboratories participating in the RERTR Program. Postirradiation examination of these plates showed satisfactory performance for the oxides, aluminides and silicides (except for the highest-loaded U 3 Si plate) with the only indication of detrimental behavior being the slight bowing of some plates at about 80% burnup

Postirradiation examination of high-U-loaded, low-enriched U3O8, UAl2, and U3Si test fuel plates

International Nuclear Information System (INIS)

Gomez, J.; Morando, R.; Perez, E.E.; Giorsetti, D.R.; Copeland, G.L.; Hofman, G.L.; Snelgrove, J.L.

1985-01-01

The scope of this work is to present an evaluation of the postirradiation examination of the second set of high-U-loaded, low-enriched U 3 O 8 , UAl 2 and U 3 Si miniature plates manufactured by the Comision Nacional de Energia Atomica (CNEA) of Argentina, and irradiated and examined, within the framework of the Reduced Enrichment Research and Test Reactor (RERTR) Program, at Oak Ridge National Laboratory and Argonne National Laboratory. This paper includes fabrication details of the plates, their irradiation history and the results of postirradiation examination which are compared to those of the previous test and to present results from other laboratories participating in the REM Program. Postirradiation examination of these plates showed satisfactory performance for the oxides, aluminides and silicides (except for the highest-loaded U 3 Si plate) with the only indication of detrimental behavior being the slight bowing of some plates at about 80% burnup. (author)

Postirradiation examination of high-U-loaded low-enriched U3O8, UAl2, and U3Si test fuel plates

International Nuclear Information System (INIS)

Gomez, J.; Morando, R.; Perez, E.E.; Giorsetti, D.R.; Copeland, G.L.; Hofmann, G.; Snelgrove, J.L.

1984-01-01

The scope of this work is to present an evaluation of the postirradiation examination of the second set of high-U-loaded low-enriched U 3 O 8 , UAl 2 and U 3 Si miniature plates manufactured by the Comision Nacional de Energia Atomica (CNEA) of Argentina, and irradiated and examinated, within the framework of the Reduced Enrichment Research and Test Reactor (RERTR) Program, at Oak Ridge National Laboratory and Argonne National Laboratory. This paper includes fabrication details of the plates, their irradiation history and the results of postirradiation examination which are compared to those of the previous test and to present results from other laboratories participating in the RERTR Program. Postirradiation examination of these plates showed satisfactory poerformance for the oxides, aluminides and silicides (except for the highest-loaded U 3 Si plate) with the only indication of detrimental behavior during the slight bowing of some plates at about 80% burnup

SU(2) x U(1) x U'(1) models which are slightly different from the Weinberg-Salam model

International Nuclear Information System (INIS)

Gao, C.; Wu, D.

1981-01-01

We discuss SU(2) x U(1) x U'(1) models by a uniform formula which is convenient for their comparison with the standard Weinberg-Salam model. As examples, we give three interesting models which are based on different grand unification models. In one model, U'(1) does not contribute to the electromagnetic interaction; in the other two, both U(1) and U'(1) do contribute to the electromagnetic interaction. Also, the first two models can approach the standard Weinberg-Salam model as close as one wants; but the third model has limitations on it

Development and characterization of monolithic fuel miniplate alloy U-2.5Zr-7.5Nb, coated in zircaloy

International Nuclear Information System (INIS)

Machado, Geraldo Correa

2014-01-01

The autocthonal production of nuclear fuel in Brazil for test and research reactors is restricted to MTR (Material Test Reactor) fuel type dispersion plate, using U3Si2 alloy, coated and dispersed in aluminum, developed by IPEN-SP for use in IEA-R1 reactor. Moreover, the UO 2 fuel rod type for power reactors is manufactured by Rezende (RJ) with a German technology by INB under license. Currently, Brazil is performing two programs of developing reactors. Currently, Brazil is developing two reactors. One of them is the development, by CNEN, the Brazilian Multipurpose Reactor (RMB), for testing, research and radioisotope production. The other one is the development a power reactor for naval propulsion, conducted by the Brazilian Navy. This dissertation presents the development and characterization of monolithic fuel miniplate alloy U-2.5Zr-7.5Nb, coated in zircaloy (ZRY), on a laboratory scale. Due to its innovative features and properties, this fuel can be used as fuel in both test reactors, research and producing radioisotopes for power reactors as small and medium sizes. Thus, this high potential fuel can be used in domestic reactors currently under development. The development of monolithic fuel plate type is made using the technique called 'picture-frame' where a sandwich composed of a monolith alloy U-2.5Zr- 7.5Nb coupled to a frame and coated sheets of Zry is obtained. The alloy U-2.5Zr-7.5Nb was obtained by melting in an induction furnace and then was cast into rectangular ingots of graphite, thus achieving an ingot with approximate dimensions of 170 x 50 x 60 mm. The obtained ingot was hot rolled at 850 ºC, with a 50 % reduction in thickness, in order to refine the raw structure of fusion. Samples cut from the alloy U-2.5Zr-7.5Nb, with dimensions 20 x 20 x 6 mm were placed in frames and plates Zry and joined by TIG (Tungsten Inert Gas) under an atmosphere of argon, obtaining a set of 10 mm thick, 45 mm wide and 100 mm long. The sandwiches were hot rolled to

Determination of 234U and 238U activity concentrations in groundwaters from three deep wells drilled in Itu Intrusive Suite (SP)

International Nuclear Information System (INIS)

Souza, Francisca de

2006-01-01

Activity concentrations of ( 234 U) and ( 238 U) were determined in groundwaters drawn from three deep wells drilled in rocks from Itu Intrusive Suite (SP), two located in Salto town (S and SY wells) and the other one in Itu (I well). Sampling was done from September, 2004 to December, 2005, and twelve samples of each well were collected monthly. For those determinations alpha spectrometry technique was used, providing high precision results, as shown by the very good agreement of the data obtained in the analyses of 23 duplicates. The waters from the three wells presented a considerable enrichment of 234 U in relation to 238 U, indicating an important radioactive disequilibrium of these isotopes. In well I, the activity concentrations of ( 238 U) varied from (1,06 +- 0,03) to (2,1+- 0,2) mBq/L and those of ( 234 U) spanned from (3,1 +- 0,2) to (6,0 +- 0,4) mBq/L, whereas ( 234 U/ 238 U) activity ratios did not present significant variation, during the sampling time interval, presenting an average of 2,8 +- 0,1. The S waters showed the lowest uranium concentrations and the largest diversity of ( 238 U) and ( 234 U) activity concentrations, which varied from (0,26 +- 0,02) to (1,07+- 0,08) mBq/L and from (1,8 +- 0,1) to (7,0 +- 0,5) mBq/L, respectively, and also presented variable ( 234 U/ 238 U) activity ratios, spanning from (2,79 +- 0,07) to (8,1+- 0,3). In SY well, ( 238 U) activities varied between (0,8 +- 0,1) and (4,2 +- 0,3) mBq/L and those ones of ( 234 U) from (14 +- 1) to (53 +- 4) mBq/L, whereas ( 234 U/ 238 U) ratios fell in the interval from 12,6 +- 0,3 to 18,3 +- 0,4, with the highest activities of both radioisotopes registered during the dry season and the lowest ones in the rainy time period. The ( 234 U/ 238 U) activity ratios, which were invariable during sampling period of well I, indicated the contribution of rainfall to recharge the aquifer. The observed correlation between those ratios and uranium concentrations, for S and SY wells, showed

PPADS and suramin as antagonists at cloned P2Y- and P2U-purinoceptors.

Science.gov (United States)

Charlton, S J; Brown, C A; Weisman, G A; Turner, J T; Erb, L; Boarder, M R

1996-06-01

1. The effect of suramin and pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) on the stimulation of phospholipase C in 1321N1 cells transfected with the human P2U-purinoceptor (h-P2U-1321N1 cells) or with the turkey P2Y-purinoceptor (t-P2Y-1321N1 cells) was investigated. 2-Methylthioadenosine triphosphate (2MeSATP) was used as the agonist at t-P2Y-1321N1 cells and uridine triphosphate (UTP) at h-P2U-1321N1 cells. 2. Suramin caused a parallel shift to the right of the concentration-response curves for 2MeSATP in the t-P2Y-1321N1 cells, yielding a Schild plot with a slope of 1.16 +/- 0.08 and a pA2 value of 5.77 +/- 0.11. 3. Suramin also caused a shift to the right of concentration-response curves for UTP in the h-P2U-1321N1 cells, and on Schild plots gave a slope different from unity (1.57 +/- 0.19) and an apparent pA2 value of 4.32 +/- 0.13. Suramin was therefore a less potent antagonist at the P2U-purinoceptor than the P2Y-purinoceptor. 4. In the presence of the ectonucleotidase inhibitor, ARL 67156 (6-N,N-diethyl-beta,gamma-dibromomethylene-D-ATP) there was no significant difference in the EC50 or shapes of curves with either cell type, and no difference in pA2 values for suramin. 5. PPADS caused an increase in the EC50 for 2MeSATP in the t-P2Y-1321N1 cells. The Schild plot had a slope different from unity (0.55 +/- 0.15) and an X-intercept corresponding to an apparent pA2 of 5.98 +/- 0.65. 6. PPADS up to 30 microM had no effect on the concentration-response curve for UTP with the h-P2U-1321N1 cells. 7. In conclusion, suramin and PPADS show clear differences in their action at the 2 receptor types, in each case being substantially more effective as an antagonist at the P2Y-purinoceptor than at the P2U-purinoceptor. Ectonucleotidase breakdown had little influence on the nature of the responses at the two receptor types, or in their differential sensitivity to suramin.

Hydrolysis of U(VI) and sodium uranates

International Nuclear Information System (INIS)

Pongi, N.-K.; Double, Gerard; Hurwic, Jozef

1980-01-01

The potentiometric titration curves of UO 2 (NO 3 ) 2 aqueous solutions by NaOH have been interpreted. The results we have got verify and complete those published before. From isohydric species (UO 2 ) 3 (OH) 7 - , with pH = 7,8 and the experimental molar value of the relation xsub(i) = Na/U = 2.33, the following ionic and molecular species in acid medium have been deduced: (UO 2 ) 2 (OH) 2 2+ , (UO 2 ) 3 (OH) 2 2+ , (UO 2 ) 3 (OH) 5 + and (UO 2 ) 3 (OH) 6 . The composition of the precipitates corresponding to the particular points of the potentiometric titration curves, by chemical, thermal decomposition analysis and by X-rays diffraction, have been carried out: (UO 2 ) 6 (OH) 12 .6H 2 O, Na 2 U 8 O 25 , Na 2 U 6 O 19 , Na 2 U 4 O 13 and Na 2 U 2 O 7 for xsub(i) = 1,67 and 2.00, 2.23, 2.33, 2.52, 3.00 and over, respectively. The uranyl hydroxide was obtained for first time from an aqueous solution [fr

Measurement of the 230U half-life

International Nuclear Information System (INIS)

Pommé, S.; Altzitzoglou, T.; Van Ammel, R.; Suliman, G.; Marouli, M.; Jobbágy, V.; Paepen, J.; Stroh, H.; Apostolidis, C.; Abbas, K.; Morgenstern, A.

2012-01-01

The 230 U half-life was determined by measuring the decay curve of 230 U sources by various nuclear detection techniques: α-particle counting at a defined small solid angle; 4πα+β counting with a windowless CsI sandwich spectrometer, a liquid scintillation counter and a pressurised proportional counter; gamma-ray spectrometry with a HPGe detector and nearly-2π α-particle counting with an ion-implanted silicon detector. Depending on the technique, the decay was followed for 100–200 d, which is 5–10 times the 230 U half-life. The measurement results of the various techniques were in good mutual agreement. The mean value, T 1/2 ( 230 U)=20.23 (2) d, is lower than the literature value which is based on one measurement in 1948 and resulted in a half-life value of 20.8 d without statement of uncertainty. A correction for the ingrowth of the long-lived 210 Pb and its daughter products may have been overlooked in the past. - Highlights: ► Half-life of 230 U determined by various nuclear detection techniques. ► Result T 1/2 ( 230 U)=20.23 (2) d is lower than the literature value. ► 230 U/ 226 Th decay series has potential use in alpha-immunotherapy.

Accelerated electron exchange between U4+ and UO22+ by foreign metal ions

International Nuclear Information System (INIS)

Obanawa, Heiichiro; Onitsuka, Hatsuki; Takeda, Kunihiko

1990-01-01

The rate constant of U 4+ -UO 2 2+ electron exchange (k et ) was increased by more than 100 times in the presence of various metal ions. The larger rate constant was observed for the smaller difference of the standard reduction potential strength between metal ion and UO 2 2+ ion (Δμ θ e ). Detailed investigation of the electron exchange reaction in the presence of Mo 5+ suggested that the mechanism of the electron transfer reaction catalyzed by metal ions is the outer-sphere type independent of U-Clcomplex ions. (author)

Comparison of Ground-Based PM2.5 and PM10 Concentrations in China, India, and the U.S.

Directory of Open Access Journals (Sweden)

Xingchuan Yang

2018-07-01

Full Text Available Urbanization and industrialization have spurred air pollution, making it a global problem. An understanding of the spatiotemporal characteristics of PM2.5 and PM10 concentrations (particulate matter with an aerodynamic diameter of less than 2.5 μm and 10 μm, respectively is necessary to mitigate air pollution. We compared the characteristics of PM2.5 and PM10 concentrations and their trends of China, India, and the U.S. from 2014 to 2017. Particulate matter levels were lowest in the U.S., while China showed higher concentrations, and India showed the highest. Interestingly, significant declines in PM2.5 and PM10 concentrations were found in some of the most polluted regions in China as well as the U.S. No comparable decline was observed in India. A strong seasonal trend was observed in China and India, with the highest values occurring in winter and the lowest in summer. The opposite trend was noted for the U.S. PM2.5 was highly correlated with PM10 for both China and India, but the correlation was poor for the U.S. With regard to reducing particulate matter pollutant concentrations, developing countries can learn from the experiences of developed nations and benefit by establishing and implementing joint regional air pollution control programs.

Synthesis of [3-14C]- and [phenyl-U-14C] olaquindox

International Nuclear Information System (INIS)

Maul, W.; Scherling, D.; Seng, F.

1981-01-01

Olaquindox is a new feed additive. [ 14 C]Olaquindox, labelled in different positions, was needed for tracer-studies of pharmacokinetics, biotransformation and residues in several species of animals. 2-[N-(2-hydroxethyl)-carbamoyl]-3-methyl-[3- 14 C]quinoxaline-1,4-dioxide([3- 14 C]Olaquindox) was synthesized from barium[ 14 C]carbonate (22 mmoles; 1.15 Ci) via [1- 14 C]acetic acid, sodium[1- 14 C]acetate, [1- 14 C]acetylchloride, ethyl[3- 14 C]acetoacetate and 2-carbethoxy-3-methyl-[3- 14 C]quinoxaline-1,4-dioxide with an overall yield of 10%, based on barium[ 14 C]carbonate. The radiochemical purity was better than 98% (tlc). The specific activities of three preparations were 10.5, 8.4 and 5.45 μCi/mg respectively. [phenyl-U- 14 C]Olaquindox was synthesized starting from [U- 14 C]aniline (19.8 mmoles; 284.4 mCi). Intermediate products were N-acetyl[U- 14 C]aniline, 2-nitro-N-acetyl[U- 14 C]aniline, 2-nitro[U- 14 C]aniline and [U- 14 C]benzofurazanoxide. The total yield was 50% as calculated for [U- 14 C]aniline. At calibration samples of two preparations showed specific activities of 49.5 and 11.1 μCi/mg respectively. The radiochemical purity was checked by tlc and exceeded 98%. (author)

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

Science.gov (United States)

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

Suppression of multiple bioactivities of interleukin-1 and interleukin-2 production by U937 conditioned medium

International Nuclear Information System (INIS)

Wiblin, R.T.; Edmonds, K.; Ellner, J.J.

1986-01-01

The human macrophage-like cell line U937 spontaneously produces a factor which blocks interleukin-1 (IL-1) activity for mouse thymocytes but not mitosis of T-lymphoblastoid cells. The authors examined the effects of U937 conditioned medium (CM) on other IL-1 activities and on interleukin-2 (IL-2) production. U937 was cultured at 5 x 10 6 /ml in RPMI-1640 at 37 0 C for 5 days. The resulting CM inhibited the mitogenic response of C3H/HeJ mouse thymocytes to an IL-1 standard, with an inhibitory of activity of 6.64 U/ml (1 U = reciprocal dilution producing 50% inhibition of maximal response). Similarly, CM inhibited (10.12 U/ml) the fibroblast stimulation promoter activity of IL-1. The effect of CM on IL-2 production was assessed in a direct assay in which IL-2 production by γ-irradiated (12,000 rads) MLA-144 lymphosarcoma cells was assayed as 3 H-thymidine incorporation in CTLL-20 cells. The suppressive activity of CM was 4.95 U/ml; CM did not interfere with the response of CTLL-20 to IL-2. These studies establish that U937 produces factors with multiple, related biological activities; U937 CM blocks IL-2 dependent (thymocyte mitogenesis) and IL-2 independent (fibroblast proliferation) IL-1 activities and interferes with production of, but not response to, IL-2. U937 is an excellent model to study growth inhibitory properties of mononuclear phagocytes

Fission cross section ratios for 233,234,236U relative to 235U from 0.5 to 400 MeV

International Nuclear Information System (INIS)

Lisowski, P.W.; Gavron, A.; Parker, W.E.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

1991-01-01

Neutron-induced fission cross section ratios from 0.5 to 400 MeV for samples of 233, 234, 236 U relative to 235 U have been measured at the WNR neutron Source at Los Alamos. The fission reaction rate was determined using a fast parallel plate ionization chamber at a 20-m flight path. Cross sections over most the energy range were also extracted using the neutron fluence determined with three different proton telescope arrangements. Those data provided the shape of the 235 U(n,f) cross section relative to the hydrogen scattering cross section. That shape was then normalized to the very accurately known value for 235 U(n,f) at 14.1 MeV to allow us to obtain cross section section values from the ratio data and our values for 235 U(n,f). 6 refs., 1 fig

Fission cross section ratios for 233,234,236U relative to 235U from 0.5 to 400 MeV

International Nuclear Information System (INIS)

Lisowski, P.W.; Gavron, A.; Parker, W.E.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

1992-01-01

Neutron-induced fission cross section ratios from 0.5 to 400 MeV for samples of 233,234,236 U relative to 235 U have been measured at the WNR neutron Source at Los Alamos. The fission reaction rate was determined using a fast parallel plate ionization chamber at a 20-m flight path. Cross sections over most of the energy range were also extracted using the neutron fluence determined with three different proton telescope arrangements. Those data provided the shape of the 235 U(n, f) cross section relative to the hydrogen scattering cross section. That shape was then normalized to the very accurately known value for 235 U(n, f) at 14.1 MeV which will allow us to obtain cross section values from the ratio data and our values for 235 U(n, f). (orig.)

Synthesis, crystal structure and optical properties of the catena-metaphosphates Ce(PO3)4 and U(PO3)4

International Nuclear Information System (INIS)

Hoeppe, Henning A.; Daub, Michi

2012-01-01

The catena-metaphosphates of tetravalent cerium and tetravalent uranium were obtained as phase pure crystalline powders by reaction of the respective dioxides with phosphoric acid at 500 C. Ce(PO 3 ) 4 and U(PO 3 ) 4 crystallise in space group C2/c (Z = 16, a Ce = 13.7696(3) Aa, b Ce = 29.7120(7) Aa, c Ce = 8.9269(2) Aa, β Ce = 90.00(1) Aa 3 and a U = 13.786(3) Aa, b U = 29.843(6) Aa, c U = 8.9720(18) Aa, β U = 90.01(3) Aa 3 ). The vibrational and optical spectra of pale yellow Ce(PO 3 ) 4 and emerald-greenish U(PO 3 ) 4 are also reported. (orig.)

Synthesis of (+)-(3R)-3-(4-fluorophenylsulfonamido)-1,2,3,4-tetrahydro-9-[5,6,7,8,12,13-u-14C]carbazoleppropanoic acid, [14C]BAY u 3405

International Nuclear Information System (INIS)

Radtke, M.; Boberg, M.; Pleiss, U.; Rosentreter, U.

1994-01-01

The title compound [ 14 C]BAY u 3405 (1) was synthesized as part of 8-step sequence. Starting from [U- 14 C]aniline hydrogensulfate the final product 1 was obtained with a specific activity of 741 MBq/mmol (20 mCi/mmol) and a radiochemical purity of > 98 % in an overall yield of 6 and 10 % depending on the method. (author)

Summary of TMX-U results: 1984. Volume 2

International Nuclear Information System (INIS)

Simonen, T.C.

1984-01-01

The following areas are covered in this volume: (1) TREQ code, (2) Fokker-Planck and Monte Carlo calculations, (3) vacuum and gas modeling, (4) TMX-U data analysis and formulary, (5) thermal barrier operation, (6) plasma stability, (7) MHD and beta limits, (8) lf fluctuations, (9) central-cell ion-cyclotron microinstability, (10) end-cell ion-cyclotron microinstability, and (11) hot electron microinstability. In addition, discussions on the following technological developments are given: (1) vacuum, (2) magnet, (3) fueling, (4) heating, (5) potential control technology, (6) diagnostic systems, and (7) computer systems

Implications of Anomalous U(1) Symmetry in Unified Models the Flipped SU(5) x U(1) Paradigm

CERN Document Server

Ellis, Jonathan Richard; Rizos, J; Ellis, John

2000-01-01

A generic feature of string-derived models is the appearance of an anomalousAbelian U(1)_A symmetry which, among other properties, constrains the Yukawacouplings and distinguishes the three families from each other. In this paper,we discuss in a model-independent way the general constraints imposed by such aU(1)_A symmetry on fermion masses, R-violating couplings and proton-decayoperators in a generic flipped SU(5) x U(1)' model. We construct all possibleviable fermion mass textures and give various examples of effective low-energymodels which are distinguished from each other by their different predictionsfor B-, L- and R-violating effects. We pay particular attention to predictionsfor neutrino masses, in the light of the recent Super-Kamiokande data.

Thermodynamic study of (alkyl esters+{alpha},{omega}-alkyl dihalides) V. H{sub m}{sup E}andV{sub m}{sup E} for 25 binary mixtures {l_brace}xC{sub u-1}H{sub 2u-1}CO{sub 2}CH{sub 3}+(1-x){alpha},{omega}-ClCH{sub 2}(CH{sub 2}){sub v-2}CH{sub 2}Cl{r_brace}, where u=1 to 5, {alpha}=1 and v={omega}=2 to 6

Energy Technology Data Exchange (ETDEWEB)

Ortega, J. [Laboratorio de Termodinamica y Fisicoquimica de Fluidos, Parque Cientifico-Tecnologico, Campus Universitario de Tafira, Universidad de Las Palmas de Gran Canaria, 35071 Las Palmas de Gran Canaria, Canary Islands (Spain)]. E-mail: jortega@dip.ulpgc.es; Marrero, E. [Laboratorio de Termodinamica y Fisicoquimica de Fluidos, Parque Cientifico-Tecnologico, Campus Universitario de Tafira, Universidad de Las Palmas de Gran Canaria, 35071 Las Palmas de Gran Canaria, Canary Islands (Spain)

2007-05-15

The experimental data of excess molar enthalpies H{sub m}{sup E} and excess molar volumes V{sub m}{sup E} are presented for a set of 25 binary mixtures comprised of the first five methyl esters C{sub u-1}H{sub 2u-1}COOCH{sub 3} (u=1 to 5) and five {alpha},{omega}-dichloroalkanes, ClCH{sub 2}(CH{sub 2}){sub v-2}CH{sub 2}Cl (v=2 to 6), obtained at a temperature of 298.15K and atmospheric pressure. Except for the mixtures with u=1 and v=2 to 6, which are all endothermic and with u=5 and v=2 to 6, which are all exothermic, the others present net endo/exothermic effects and these mixing effects evolve quasiregularly, from endothermic to exothermic, depending on the dichloroalkane present. However, the V{sub m}{sup E} are positive in most mixtures except for those corresponding to u=4,5 and v=5,6, which present contraction effects. These results indicate a set of specific interactions with simultaneous effects for V{sub m}{sup E} of expansion/contraction and for exothermic/endothermic H{sub m}{sup E} for this set of mixtures. The change in V{sub m}{sup E} with the chain length of the compounds is irregular. To achieve a good application of the UNIFAC model using the version of Dang and Tassios, parameters of the ester (G)/dichloride (G') interaction were calculated again, making a distinction, during its application, dependent on the acid part of the ester u. Hence, interaction parameters are presented as a function of u, and of the dichloroalkane chain length v. The most appropriate general expression was of the type:a{sub G/G{sup '}}={phi}(u,v)={sigma}sub(i=0)sup(n)a{sub i-1}u{sup i-1}+{sigma}sub(i=0= )sup(n)b{sub i-1}v{sup i-1}and with this proposal good estimations of enthalpies were obtained with the UNIFAC model.

Dicty_cDB: Contig-U15069-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U15069-1 no gap 1241 1 2719927 2720886 PLUS 37 43 U15069 16 2 0 0 0 5 8 0 0 1 1 0 4 0 Show Contig...-U15069-1 Contig ID Contig-U15069-1 Contig update 2004. 6.11 Contig sequence >Contig-U15069-1 (Contig...-U15069-1Q) /CSM_Contig/Contig-U15069-1Q.Seq.d TTTCAAACCAAAACATAAAATAATTAAAAATGACAACTGTTAAACCA...AAAAATAAAATAAATAAAAATAGTTTTAAA Gap no gap Contig length 1241 Chromosome number (1..6, M) 1 Chromosome length...07Z ,263,623 est42= VSJ431Z ,390,646 est43= CHB363Z ,460,1187 Translated Amino Acid sequence snqnik*lkmttvkptspenprvffditig

uPA/uPAR system activation drives a glycolytic phenotype in melanoma cells.

Science.gov (United States)

Laurenzana, Anna; Chillà, Anastasia; Luciani, Cristina; Peppicelli, Silvia; Biagioni, Alessio; Bianchini, Francesca; Tenedini, Elena; Torre, Eugenio; Mocali, Alessandra; Calorini, Lido; Margheri, Francesca; Fibbi, Gabriella; Del Rosso, Mario

2017-09-15

In this manuscript, we show the involvement of the uPA/uPAR system in the regulation of aerobic glycolysis of melanoma cells. uPAR over-expression in human melanoma cells controls an invasive and glycolytic phenotype in normoxic conditions. uPAR down-regulation by siRNA or its uncoupling from integrins, and hence from integrin-linked tyrosine kinase receptors (IL-TKRs), by an antagonist peptide induced a striking inhibition of the PI3K/AKT/mTOR/HIF1α pathway, resulting into impairment of glucose uptake, decrease of several glycolytic enzymes and of PKM2, a checkpoint that controls metabolism of cancer cells. Further, binding of uPA to uPAR regulates expression of molecules that govern cell invasion, including extracellular matrix metallo-proteinases inducer (EMPPRIN) and enolase, a glycolytyc enzyme that also serves as a plasminogen receptor, thus providing a common denominator between tumor metabolism and phenotypic invasive features. Such effects depend on the α5β1-integrin-mediated uPAR connection with EGFR in melanoma cells with engagement of the PI3K-mTOR-HIFα pathway. HIF-1α trans-activates genes whose products mediate tumor invasion and glycolysis, thus providing the common denominator between melanoma metabolism and its invasive features. These findings unveil a unrecognized interaction between the invasion-related uPAR and IL-TKRs in the control of glycolysis and disclose a new pharmacological target (i.e., uPAR/IL-TKRs axis) for the therapy of melanoma. © 2017 UICC.

Higgs phenomenology in the minimal S U (3 )L×U (1 )X model

Science.gov (United States)

Okada, Hiroshi; Okada, Nobuchika; Orikasa, Yuta; Yagyu, Kei

2016-07-01

We investigate the phenomenology of a model based on the S U (3 )c×S U (3 )L×U (1 )X gauge theory, the so-called 331 model. In particular, we focus on the Higgs sector of the model which is composed of three S U (3 )L triplet Higgs fields and is the minimal form for realizing a phenomenologically acceptable scenario. After the spontaneous symmetry breaking S U (3 )L×U (1 )X→S U (2 )L×U (1 )Y , our Higgs sector effectively becomes that with two S U (2 )L doublet scalar fields, in which the first- and the second-generation quarks couple to a different Higgs doublet from that which couples to the third-generation quarks. This structure causes the flavor-changing neutral current mediated by Higgs bosons at the tree level. By taking an alignment limit of the mass matrix for the C P -even Higgs bosons, which is naturally realized in the case with the breaking scale of S U (3 )L×U (1 )X much larger than that of S U (2 )L×U (1 )Y, we can avoid current constraints from flavor experiments such as the B0-B¯ 0 mixing even for the Higgs bosons masses that are O (100 ) GeV . In this allowed parameter space, we clarify that a characteristic deviation in quark Yukawa couplings of the Standard Model-like Higgs boson is predicted, which has a different pattern from that seen in two Higgs doublet models with a softly broken Z2 symmetry. We also find that the flavor-violating decay modes of the extra Higgs boson, e.g., H /A →t c and H±→t s , can be dominant, and they yield the important signature to distinguish our model from the two Higgs doublet models.

Impact of uranium (U) on the cellular glutathione pool and resultant consequences for the redox status of U.

Science.gov (United States)

Viehweger, Katrin; Geipel, Gerhard; Bernhard, Gert

2011-12-01

Uranium (U) as a redox-active heavy metal can cause various redox imbalances in plant cells. Measurements of the cellular glutathione/glutathione disulfide (GSH/GSSG) by HPLC after cellular U contact revealed an interference with this essential redox couple. The GSH content remained unaffected by 10 μM U whereas the GSSG level immediately increased. In contrast, higher U concentrations (50 μM) drastically raised both forms. Using the Nernst equation, it was possible to calculate the half-cell reduction potential of 2GSH/GSSG. In case of lower U contents the cellular redox environment shifted towards more oxidizing conditions whereas the opposite effect was obtained by higher U contents. This indicates that U contact causes a consumption of reduced redox equivalents. Artificial depletion of GSH by chlorodinitrobenzene and measuring the cellular reducing capacity by tetrazolium salt reduction underlined the strong requirement of reduced redox equivalents. An additional element of cellular U detoxification mechanisms is the complex formation between the heavy metal and carboxylic functionalities of GSH. Because two GSH molecules catalyze electron transfers each with one electron forming a dimer (GSSG) two UO(2) (2+) are reduced to each UO(2) (+) by unbound redox sensitive sulfhydryl moieties. UO(2) (+) subsequently disproportionates to UO(2) (2+) and U(4+). This explains that in vitro experiments revealed a reduction to U(IV) of only around 33% of initial U(VI). Cellular U(IV) was transiently detected with the highest level after 2 h of U contact. Hence, it can be proposed that these reducing processes are an important element of defense reactions induced by this heavy metal.

The valence state of uranium in K{sub 6}Cu{sub 12}U{sub 2}S{sub 15}

Energy Technology Data Exchange (ETDEWEB)

Schilder, H; Speldrich, M; Lueken, H; Sutorik, A C; Kanatzidis, M G

2004-07-14

The paramagnetic behaviour of K{sub 6}Cu{sub 12}U{sub 2}S{sub 15} has been analysed, regarding copper as diamagnetic (Cu{sup +}), sulfur as mixed-valent S{sup 2-}/S{sup -} with magnetically silent delocalized S{sup -} holes in the valence band, and the actinide as either U{sup 5+}[5f{sup 1}] or U{sup 4+}[5f{sup 2}] in trigonally distorted octahedral surrounding (pseudosymmetry 3-bar) of sulfur. Fitting procedures have been carried out, accounting for spin-orbit coupling, ligand-field potential (parameters B{sup k}{sub q}), interelectronic repulsion (for U{sup 4+}[5f{sup 2}]), cooperative magnetic effects (molecular field parameter {lambda}), and applied magnetic field. Keeping the ratios B{sup 4}{sub 3}/B{sup 4}{sub 0}, B{sup 6}{sub 3}/B{sup 6}{sub 0}, B{sup 6}{sub 6}/B{sup 6}{sub 0} on their point charge electrostatic values with respect to the sulfur ligands, the three axial parameters B{sup k}{sub 0} (k=2,4,6) and {lambda} were refined. Agreement between measured and calculated susceptibility data was obtained for U{sup 5+} with B{sup k}{sub 0} values expected for octahedral surrounding and {lambda}<0 speaking for antiferromagnetic interactions. The U{sup 4+} model does yield a fit of comparable quality, but gives B{sup k}{sub 0} values that are unreasonable with respect to sign and magnitude. To conclude, on the basis of the magnetic properties the title compound is a 5f{sup 1} system corresponding to the elements formal charges (K{sup +}){sub 6}(Cu{sup +}){sub 12}(U{sup 5+}){sub 2}(S{sup 2-}){sub 13}(S{sup -}){sub 2}.

Preparation of 235mU targets for 235U(n,n')235mU cross section measurements

International Nuclear Information System (INIS)

Bond, E.M.; Vieira, D.J.; Rundberg, R.S.; Glover, S.; Hynek, D.; Jansen, Y.; Becker, J.; Macri, R.

2008-01-01

This paper describes the preparation of samples for an experiment to measure the cross-section for 235 U(n,n') 235m U in a fast fission spectrum of neutrons provided by a fast pulsed reactor/critical assembly. Samples of 235m U have been prepared for the calibration of the internal conversion electron detector that is used for the 235m U measurement. Two methods are described for the preparation of 235 mU. The first method used a U-Pu chemical separation based on anion-exchange chromatography and the second method used an alpha recoil collection method. Thin, uniform samples of 235m U+ 235 U were prepared for the experiment using electrodeposition. (author)

Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with the International Gamma-Ray Astrophysics Laboratory

Science.gov (United States)

Hemphill, Paul B.; Rothschild, Richard E.; Caballero, Isabel; Pottschmidt, Katja; Kuhnel, Matthias; Furst, Felix; Wilms, Jorn

2013-01-01

We present a spectral and timing analysis of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of two high-mass X-ray binaries, 4U 1538-522 and 4U 1907+09. Our timing measurements for 4U 1538-522 find the pulse period to have exhibited a spin-up trend until approximately 2009, after which there is evidence for a torque reversal, with the source beginning to spin down to the most recently measured period of 525.407 plus or minus 0.001 seconds. The most recent INTEGRAL observations of 4U 1907+09 are not found to yield statistically significant pulse periods due to the significantly lower flux from the source compared with 4U 1538-522. A spectral model consisting of a power-law continuum with an exponential cutoff and modified by two cyclotron resonance scattering features is found to fit both sources well, with the cyclotron scattering features detected at approximately 22 and approximately 49 kiloelectronvolts for 4U 1538-522 and at approximately 18 and approximately 36 kiloelectronvolts for 4U 1907+09. The spectral parameters of 4U 1538-522 are generally not found to vary significantly with flux and there is little to no variation across the torque reversal. Examining our results in conjunction with previous work, we find no evidence for a correlation between cyclotron line energy and luminosity for 4U 1538-522. 4U 1907+09 shows evidence for a positive correlation between cyclotron line energy and luminosity, which would make it the fourth, and lowest luminosity, cyclotron line source to exhibit this relationship.

Structure and Lamb shift of 2s1/2-2p3/2 levels in lithiumlike U89+ through neonlike U82+

International Nuclear Information System (INIS)

Beiersdorfer, P.; Knapp, D.; Marrs, R.E.; Elliott, S.R.; Chen, M.H.

1993-01-01

The first Doppler-shift-free crystal-spectrometer measurement of stationary highly stripped uranium ions from a high-energy electron beam ion trap is presented. Thirteen 2s 1/2- 2p 3/2 transitions in eight ionization states bteween Li-like U 89+ and Ne-like U 82+ are identified and measured with an accuracy as high as 37 ppm, providing benchmarks for testing relativistic correlation and quantum electrodynamic effects in highly charged multielectron ions. A value of 47.39±0.35 eV is found for the 2s 1/2 Lamb shift in Li-like U 89+ , in excellent agreement with theory

Structure and lamb shift of 2s1/2-2p3/2 levels in lithiumlike U89+ through neonlike U82+

International Nuclear Information System (INIS)

Beiersdorfer, P.; Knapp, D.; Marrs, R.E.; Elliott, S.; Chen, M.H.

1993-01-01

The first Doppler-shift-free crystal- spectrometer measurements from stationary highly stripped uranium ions are presented. Eleven 2s 1/2 -2p 3/2 transitions in eight ionization stages between Li-like U 89+ and Ne-like U 82+ are identified and measured with an accuracy as high as 45 ppm, providing benchmarks for testing relativistic correlation and quantum electrodynamical effects in highly charged multi-electron ions. A value of 47.38 ± 0.35 eV is found for the 2s 1/2 Lamb shift in Li-like U 89+ , in excellent agreement with the theoretical value of 47.58 eV

Bose-Fermi U(6/2j+1) supersymmetries and high-spin anomalies

International Nuclear Information System (INIS)

Morrison, I.; Jarvis, P.D.

1985-01-01

A supersymmetric extension of the interacting boson model (IBM) is constructed to describe high-spin anomalies in both even- and odd-mass spectra of the Hg, Pt region (190<=A<=200). Supergroup chains such as U(6/2j+1)containsOsp(6/2j+1)containsO(6)xSp(2j+1)... or U(6/2j+1)containsU(5/2j+1)xU(1)containsOsp(5/2j+1)... incorporate a single j-shell fermion in addition to the usual 's' and 'd' bosons (L=0 and L=2). The orthosympletic supergroup reflects the strong pairing force in the subspace of the fermion intruder level. The model agrees favourably with experiment and microscopic calculation. (orig.)

Dicty_cDB: Contig-U06307-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U06307-1 no gap 637 6 29174 29801 PLUS 4 5 U06307 4 0 0 0 0 0 0 0 0 0 0 0 0 0 Show Contig...-U06307-1 Contig ID Contig-U06307-1 Contig update 2002. 9.13 Contig sequence >Contig-U06307-1 (Contig...-U06307-1Q) /CSM_Contig/Contig-U06307-1Q.Seq.d CCCGCGTCCGAATGCCTCGTATTTTACACACTATGCTCCGTGTGGGTAAT TTAG...ATAGTATTTTTATTTTATT CTTTTTCTTTTAAAAATTTTTTATATTGTCAACAATATAATCAAATAAAT GTATTTAATTATCGGGTATTAAAAAAAAAAAAAAAAA Gap no gap Contig...own update 2004. 6.10 Homology vs CSM-cDNA Query= Contig-U06307-1 (Contig-U06307-1Q) /CSM_Contig/Contig-U063

DENSITY-FUNCTIONAL STUDY OF U-Mo AND U-Zr ALLOYS

Energy Technology Data Exchange (ETDEWEB)

Landa, A; Soderlind, P; Turchi, P A

2010-11-01

Density-functional theory previously used to describe phase equilibria in U-Zr alloys [A. Landa, P. Soederlind, P.E.A. Turchi, J. Alloys Comp. 478 (2009) 103-110] is extended to investigate the ground-state properties of U-Mo solid solutions. We discuss how the heat of formation in both alloys correlates with the charge transfer between the alloy components, and how the specific behavior of the density of states in the vicinity of the Fermi level promotes the stabilization of the U{sub 2}Mo compound. Our calculations prove that, due to the existence of a single {gamma}-phase over the typical fuel operation temperatures, {gamma}-U-Mo alloys should indeed have much lower constituent redistribution than {gamma}-U-Zr alloys for which binodal decomposition causes a high degree of constituent redistribution.

Thermodynamic stabilities of MO2+x(s) (M = U, Np, Pu and Am), pourbaix diagrams

International Nuclear Information System (INIS)

Vitorge, Pierre; Faure, Marie-Helene; Vercouter, Thomas; Capdevila, Helene; Maillard, Serge

2002-01-01

The experimental solubilities of the hydrated amorphous freshly precipitated M(OH) z (am) and MO 2 (OH) z (am) compounds are often used as an upper limit for the safety assessments of deep waste repositories, since these compounds slowly transform to less soluble ones, as typically M(OH) 4 (am) to MO 2 (cr). Solubility (vs. redox potential) at pH=8, and E-pH predominance diagrams are plotted in aqueous solutions at 25degC by using thermodynamic data recently selected by the NEA-TDB review, or estimated by using classical chemical analogies for the non-redox reactions. The solubilities and relative stabilities are also calculated for the MO 2+x (s) crystalline compounds of known stabilities: U 4 O 9 (s), U 3 O 7 (s), U 3 O 8 (s) and Np 2 O 5 (s) where 2+x = 2.25, 2.33, 2.67 and 2.5 respectively. The stabilities of the other MO 2+x (s) compounds are estimated by analogy: M 4 O 9 (s) (M=U, Np, Pu), M 3 O 7 (s) and M 3 O 8 (s) (M=U, Pu), and M 2 O 5 (s) (M=Np, Am) are predicted to be more stable (i.e. less soluble), than the amorphous hydroxides. However their precipitation have never been observed at room temperature possibly for kinetic reasons or difficulties in interpreting solubility experiments. (author)

Corrective action baseline report for underground storage tanks 0439-U, 0440-U, 2073-U, 2074-U, and 2075-U at the East End Fuel Station, Buildings 9754 and 9754-2, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee, Facility ID No. 0-010117

International Nuclear Information System (INIS)

1994-01-01

The purpose of this report is to provide baseline geochemical and hydrogeologic data relative to corrective action for underground storage tanks (USTs) 0439-U, 0440-U, 2073-U, 2074-U, and 2075-U at the East End Fuel Station, Buildings 9754 and 9754-2 at the Oak Ridge Y-12 Plant. Progress in support of corrective action at the East End Fuel Station has included monitoring well installation, tank removal, and baseline groundwater sampling and analysis. This document represents the baseline report for corrective action at the East End Fuel Station and is organized into three sections. Section 1 presents introductory information relative to the site, including the regulatory initiative, site description, and progress to date. Section 2 includes a summary of additional monitoring well installation activities, the results of baseline groundwater sampling, a summary of tank removal activities, and the results of confirmatory soil sampling performed during tank removal. Section 3 presents the baseline hydrogeology and planned zone of influence for groundwater remediation

Industrija 4.0 - sadašnjost ili budućnost u Hrvatskoj

OpenAIRE

Matejak, Nedeljko

2017-01-01

Tehnološki razvoj generator je dinamičnih promjena gotovo u svim područjima koje dotiče. Jedno od područja koje prolazi kroz intenzivnu tranziciju je industrijska proizvodnja. U prilog tome govori transformacija iz treće industrijske revolucije u četvrtu, dok zapravo dio globalne ekonomije nije napravio potpunu transformaciju u treću industrijsku revoluciju. Pojam Industrija 4.0 opisuje što se nalazi na putu transformacije postojeće industrijske proizvodnje u novu, primarn...

Intenzitet stresa kod učitelja u osnovnim školama

OpenAIRE

Tomašević, Suzana; Horvat, Gordana; Leutar, Zdravka; Horvat, Gordana

2016-01-01

Cilj ovog rada bio je istražiti intenzitet stresa kod učitelja razredne i predmetne nastave u seoskim i gradskim osnovnim školama. Ovim istraživanjem želi se utvrditi postoji li statistički značajna razlika u intenzitetu stresa između učitelja razredne nastave i učitelja predmetne nastave s obzirom na mjesto rada, selo ili grad. U istraživanju je korišten psihologijski instrument za mjerenje percepcije stresa (PerceivedStressScale) (Cohen, S., Kamarck, T, Mermelstein, R. 1983). Istraživanj...

Characterization of the interaction layer in diffusion couples U-Mo-Zr/Al and U-Mo-Zr/Al-A356 at 550 C degrees

International Nuclear Information System (INIS)

Komar Varela, Carolina; Arico, Sergio; Mirandou, Marcela; Balart, Silvia; Gribaudo, Luis

2007-01-01

Out-of-pile diffusion experiments were performed between U-7 wt.% Mo-1 wt.% Zr and Al or Al A356 (7,1 wt.% Si) at 550 C degrees. In this work morphological characterization and phase identification on both interaction layers are presented. They were carried out by the use of different techniques: optical and scanning electron microscopy, X-ray diffraction and WDS microanalysis. In the interaction layer U-7 wt.% Mo-1 wt.% Zr/Al, the phases UAl 3 , UAl 4 , Al 20 Mo 2 U and Al 43 Mo 4 U 6 were identified. Similar results in the interaction layer of the U-7 % Mo/Al at 580 C degrees were previously obtained. In the interaction layer U-7 wt.% Mo-1 wt.% Zr/Al A356, the phases U(Al,Si) 3 with 25 at.% Si and Si 5 U 3 were identified. This last phase, with a higher Si concentration, was identified with X-ray diffraction synchrotron radiation performed at the National Synchrotron Light Laboratory, Campinas, Brazil. (author) [es

A COMPARISON OF (PuU)C AND (PuU)O$sub 2$ FUELED FAST BREEDER REACTORS

Energy Technology Data Exchange (ETDEWEB)

Kazi, A. Halim; Rosen, Stanley

1963-11-15

BS>A conceptual evaluation is presented of a (PuU)C 500Mw(e) reactor which uses a moderate power generation of 40 kw/ft and a maximum fuel temperature of 2900 deg F, well below the 4500 deg F melting point of Pu/sub 0.2/U/sub 0.8/C. The principal design characteristics and fuel cycle costs are tabulated together with those of a (PuU)O/sub 2/ design of equal power. The comparison shows that the carbide core has significant economic and safety advantages over the oxide core. (D.L.C.)

Environmental control of U concentration and 234U/238U in speleothems at subannual resolution

Science.gov (United States)

Hu, C.; Henderson, G. M.

2003-12-01

Trace element and isotope variability in speleothems encodes a range of information about the past environment, although its interpretation is often problematic. U concentration and isotopes have frequently been analysed in speleothems in order to provide chronology, but their use as environmental proxies in their own right has not been comprehensively investigated. In this study, we have investigated the environmental controls of U in a stalagmite from the Central Yangtze Valley in China. This stalagmite grew rapidly throughout the Holocone and contains visible annual layers about 300microns thick. Analysis of a portion of the stalagmite corresponding to the 1970s by electron probe, LA-ICP-MS, and by physical subsampling indicate clear annual cycles in Sr/Ca, Mg/Ca, and Ba/Ca. The reasonably open cave structure and the correlation of Sr/Ca with Mg/Ca suggest that temperature exerts considerable control over these trace element variations. U/Ca also varies seasonally by up to 42 % and shows a clear anti-correlation with Mg/Ca (correlation coefficient -0.64). Based on the inverse relationship between U/Ca and temperature exhibited in other carbonates (e.g. corals) the speleothem U/Ca is suggested to be controlled primarily by temperature and may provide a paleo cave thermometer with less rainfall influence than Mg/Ca. Ongoing monitoring of the cave temperature and humidity will assess the robustness of this conclusion and the sensitivity of speleothem U/Ca to temperature. (234U/238U) in this stalagmite range from 1.733 to 1.872 during the Holocene. The U concentration is high enough (typically 0.48 ppm) and growth rate fast enough, that (234U/238U) can also be measured at a subannual resolution. The expected alpha-recoil control of excess 234U supply suggests that these measurements may provide a measure of the transit time of recharge waters to the stalagmite during the seasonal cycle. Such a proxy would enable deconvolution of temperature and recharge-rate control

Single-site properties of U impurities doped in La2Zn17 (abstract)

Science.gov (United States)

Suzuki, H.; Anzai, K.; Takagi, S.

1997-04-01

Thermodynamic and transport properties of heavy Fermion (HF) U compounds show similar behavior to HF Ce compounds. Although most of the magnetic properties of HF Ce compounds can be qualitatively understood on the basis of the impurity Kondo model, no such consensus for HF U compounds has been reached. In addition to this, the single-site properties of U impurities are not understood so well, in contrast to the case of Ce impurities. Recent works for dilute U systems reported new features as are not seen in dilute Ce systems. We have investigated a dilute-U2Zn17 system of (La1-zUz)2Zn17 in order to reveal the single U ion site properties of this system by preparing single crystals. The impurity contributions to various physical quantities such as ρimp(T), χimp(T), and Cimp(T) can be scaled by the U concentration between z=0.025 and 0.05, and the system is considered as in the dilute limit still for z=0.05. The electrical resistivity shows the typical impurity-Kondo upturn at low temperatures. The electronic specific-heat coefficient is strongly enhanced (γimp≈1.5 J/K2 mole U) and about 4 times as large as that for dense U2Zn17. Suppressions of the Kondo effect by the magnetic field are seen in γimp(H) and magnetoresistance. The relatively large anisotropy in χimp(T) indicates an existence of the crystal field. These features of this system will be explained in terms of the Kondo effect in the presence of the crystal field.

4U 1907+09: an HMXB running away from the Galactic plane

Science.gov (United States)

Gvaramadze, V. V.; Röser, S.; Scholz, R.-D.; Schilbach, E.

2011-05-01

We report the discovery of a bow shock around the high-mass X-ray binary (HMXB) 4U 1907+09 using the Spitzer Space Telescope 24 μm data (after Vela X-1 the second example of bow shocks associated with HMXBs). The detection of the bow shock implies that 4U 1907+09 is moving through space with a high (supersonic) peculiar velocity. To confirm the runaway nature of 4U 1907+09, we measured its proper motion, which for an adopted distance to the system of 4 kpc corresponds to a peculiar transverse velocity of ≃ 160 ± 115 km s-1, meaning that 4U 1907+09 is indeed a runaway system. This also supports the general belief that most HMXBs possess high space velocities. The direction of motion of 4U 1907+09 inferred from the proper motion measurement is consistent with the orientation of the symmetry axis of the bow shock, and shows that the HMXB is running away from the Galactic plane. We also present the Spitzer images of the bow shock around Vela X-1 (a system similar to 4U 1907+09) and compare it with the bow shock generated by 4U 1907+09.

Structure of tris(trimethylsilylcyclopentadienyl)uranium(III), [(CH3)3SiC5H43U

International Nuclear Information System (INIS)

Brennan, J.; Andersen, R.A.; Zalkin, A.

1986-02-01

Crystals of [(CH 3 ) 3 SiC 5 H 4 ] 3 U are orthorhombic, Pbca, with a = 22.630(8), b = 29.177(10) and c = 8.428(3) A at 23 0 C. For Z = 8 the calculated density is 1.551 g/cm 3 . The structure was refined by full-matrix least-squares to a conventional R factor of 0.041 [2251 data, F 2 > 2 sigma(F 2 )]. The uranium atom is bonded to the three cyclopentadienyl rings in a pentahapto fashion and is in the plane of the ring centroids. The U to ring distances are 2.54, 2.47 and 2.51 A, and the average U-C distance is 2.78 +- 0.04 A. 7 refs., 1 fig., 3 tabs

State diagram of U-Al-Si as a basis for analysis of the processes in nuclear fuel compositions based on U(Al, Si)3 and U3Si compounds

International Nuclear Information System (INIS)

Chebotarev, N.T.; Konovalov, L.N.; Zhmak, V.A.; Chebotarev, Ya.N.

1996-01-01

Results of studies into the Al-UAl 3 -USi 3 -Si of the U-Al-Si ternary system are presented. It is established that phase equilibrium between the intermetallic compound U(Al, Si) 3 and the aluminium-silicon alloys may be presented in form of conodes on the isothermal cross-section of the state diagram. It is shown that the U(Al, Si) 3 intermetallic compound, containing up to 6.5 at.% silicon, interacts both with liquid and solid aluminium with the U(Al, Si) 4 phase formation [ru

Production of U92+ with an EBIT

International Nuclear Information System (INIS)

Marrs, R.E.

1995-01-01

A super electron beam ion trap has been used to produce bare U 92+ ions at an electron beam energy of 198 keV. Evaporative cooling with light ions was used to trap a population of 5 x 10 4 highly charged uranium ions for many seconds and reduce their temperature to less than 2q eV, suggesting that a very low emittance source of these ions is possible. Roughly 10 U 92+ and 500 U 91+ ions were present in the Super EBIT as determined from x-ray emission spectra of the trapped ions

U.S., U.S.S.R. Marine Expedition

Science.gov (United States)

Wainger, Lisa A.

An historic expedition involving U.S. and U.S.S.R. scientists may open a new era of cooperation in marine research. A University of California, San Diego/Scripps Institution of Oceanography ship carrying a team that includes two Soviet scientists is on an expedition that will take the R/V Thomas Washington into the Exclusive Economic Zone (EEZ) of the U.S.S.R. For the first time in a decade a U.S. research vessel has been given permission to operate in the Soviet Union's EEZ, according to Department of State representative Tom Cocke, who worked with Scripps on this project. The ship will also operate in the U.S. EEZ and international waters.

U(IV) fluorescence spectroscopy. A new speciation tool

Energy Technology Data Exchange (ETDEWEB)

Lehmann, Susanne; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Steudtner, Robin [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

2017-06-01

We combined absorption and fluorescence spectroscopy to study the speciation of U(IV) in solution in concentrations down to 10{sup -6} M uranium. With our time-resolved laser-induced fluorescence setup we could determine the fluorescence decay time of U(IV) in perchloric as well as in chloric acid with 2.6 ± 0.3 ns at room temperature and 148.4 ± 6.5 ns at liquid nitrogen temperature. For the U(IV) sulfate system, we observed a bathochromic shift and a peak shape modification in the fluorescence spectra with increasing sulfate concentration in solution. Thus, the potential of U(IV) fluorescence for speciation analysis could be proven.

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

Science.gov (United States)

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.

A yeast endoribonuclease stimulated by Novikoff hepatoma small nuclear RNAs U1 and U2

International Nuclear Information System (INIS)

Stevens, A.

1982-01-01

Using [ 3 H]m 7 Gppp[ 14 C]RNA-poly(A) from yeast as a substrate, an endoribonuclease has been detected in enzyme fractions derived from a high salt wash of ribonucleoprotein particles of Saccharomyces cerevisiae. The [ 3 H]m 7 Gppp[ 14 C]RNA-poly(A) seems to be a preferred substrate since other polyribonucleotides are hydrolyzed more slowly, if at all. The enzyme is inhibited by ethidium bromide, but fully double-stranded polyribonucleotides are not hydrolyzed. The hydrolysis of [ 3 H]m 7 Gppp[ 14 C]RNA-poly(A) is stimulated about 2.5-fold by the addition of small nuclear RNAs U1 and U2 of Novikoff hepatoma cells. Results show that the stimulation involves an interaction of the labeled RNA with the small nuclear RNA

Kinetics of U(VI) reduction control kinetics of U(IV) reoxidation

International Nuclear Information System (INIS)

Senko, J.M.; Minyard, M.L.; Dempsey, B.A.; Roden, E.E.; Yeh, G.-T.; Burgos, W.D.

2006-01-01

For the in situ reductive immobilization of U to be an acceptable strategy for the removal of that element from groundwater, the long-term stability of U(IV) must be determined. Rates of biotransformation of Fe species influence the mineralogy of the resulting products (Fredrickson et al., 2003; Senko et al., 2005), and we hypothesize that the rate of U(VI) reduction influences the mineralogy of resultant U(IV) precipitates. We hypothesize that slower rates of U(VI) reduction will yield U(IV) phases that are more resistant to reoxidation, and will therefore be more stable upon cessation of electron donor addition. U(IV) phases formed by relatively slow reduction may be more crystalline or larger in comparison to their relatively rapidly-formed counterparts (Figure 1), thus limiting the reactivity of slowly-formed U(IV) phases toward various oxidants. The physical location of U(IV) precipitates relative to bacterial cells may also limit the reactivity of biogenic U(IV) phases. In this situation, we expect that precipitation of U(IV) within the bacterial cell may protect U(IV) from reoxidation by limiting physical contact between U(IV) and oxidants (Figure 1). We assessed the effect of U(VI) reduction rate on the subsequent reoxidation of biogenic U(IV) and are currently conducting column scale studies to determine whether U(VI) reduction rate can be manipulated by varying the electron donor concentration used to stimulate U(VI) reduction

Study of the initial oxidation of the U4Zr2Nb alloy by X-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Mendonca, Renato de; Ferraz, Wilmar B.; Braga, Daniel M.; Macedo, Waldemar A.A.

2009-01-01

In this work, the initial stages of oxidation of the U4Zr2Nb alloy in O 2 atmosphere were studied in-situ, in ultrahigh vacuum, by X-ray photoelectron spectroscopy (XPS), an advanced surface-sensitive technique. After several hours of Ar + ion-sputtering to surface cleanness, the O 2 exposures was realized on the sample at room temperature. The evolution of oxide film formed on the sample surface was followed by XPS measures, by using Mg K α radiation of 1253.6 eV and a CLAM-2 (Vacuum Generator) electron energy analyzer. The changes of U 4f, Nb 3d, Zr 3d and O 1s photoemission peaks with O 2 exposure indicate that the adsorption of oxygen on the U4Zr2Nb alloy surface leads to fast formation of UO 2 . The alloying elements show slower oxidation and different compounds are observed in Nb 3d spectra analysis. This work shows an expressive enlargement of Nb 3d peak at 100 Langmuir exposure, indicating the formation of Nb 2 O 5 and NbO in the oxide. On the other hand, the binding energy of Zr 3d suggests that the ZrO 2 formation is stable as well as uranium dioxide. (author)

Quantitative dissolution of (U, Pu)O2 MOX (0.4% to 44% PuO2) using microwave heating technique

International Nuclear Information System (INIS)

Malav, R.K.; Fulzele, Ajit K.; Prakash, Amrit; Afzal, Md.; Panakkal, J.P.

2011-01-01

AFFF has fabricated the (U, Pu)O 2 mixed oxide fuels for PHWRs, BWRs, PFBRs and FBTRs. The quantitative dissolution of the fuel samples are required within time for accurate determination of uranium-plutonium in chemical quality control laboratory. This paper describes the use of microwave heating technique in quantitative dissolution of (U, Pu)O 2 MOX (from 0.4% to 44% PuO 2 ). (author)

Kinetics and mechanism of photoaccelerated isotope exchange between U(VI) and U(IV) in oxalate solutions

International Nuclear Information System (INIS)

Shaban, I.S.; Owreit, M.F.; Nikitenko, S.I.

1992-01-01

A kinetic study of thermal and photoaccelerated U(IV)-U(VI) isotope exchange has been carried out in oxalate solutions at 11-40 deg C. The rate and quantum yield were determined as a function of U(IV), U(VI) and oxalate concentration, wavelength of incident light, temperature and absorbed dose of γ-radiation. The kinetic equations for thermal and photoaccelerated exchange have been obtained. It was assumed that the mechanism of exchange involves formation of U(V) as an intermediate, followed by slow exchange between U(V) and U(IV). The isokinetic dependence confirms the identity of limiting stages for thermal and photostimulated exchange. The upper component of photoexcited T 1 level of uranyl is supposed to be the most reactive in the process of U(V) generation. It was observed that the small doses of γ-radiation evoke the acceleration of isotope exchange, however, at D>100 krad the rate of exchange is reduced to the level of thermal exchange. (author) 8 refs.; 4 figs.; 2 tabs

Perspektive promidžbe u XXI. stoljeću

OpenAIRE

Haramija, Predrag; Njavro, Đuro; Propat Darrer, Jagoda

2012-01-01

Otkriće i primjena novih postupaka u promidžbi ovisna je o dvjema vrstama silnica; s jedne strane, o novim tehničkim ili tehnološkim otkrićima glede sredstava komunikacije, a s druge strane o novim situacijama odnosno okolnostima u gospodarskome i društvenom okružju. U radu se prikazuje dosadašnji razvoj i istražuju moguće dominantne tendencije promidžbe u XXI. stoljeću. Početak XXI. stoljeća obilježava zasićenost potrošača mnoštvom promidžbenih poruka i sve veće nepovjerenje u njih, s...

Magnetic structure of the heavy-fermion compound U2Zn17

DEFF Research Database (Denmark)

Cox, D. E; Shirane, G.; Shapiro, S. M.

1986-01-01

The phase transition of U2Zn17 at 9.7K has been investigated by neutron powder diffraction. The transition corresponds to the onset of antiferromagnetic order where the U moments are oriented antiparallel to their neighbors within the basal planes and the near neighbor along the c^ axis of this r...... of this rhombohedral compound. At 5K, the ordered moments lie within the basal planes and are of magnitude (0.8±0.1) μB, which is substantially below the paramagnetic moment of 2.25 μB/U atom given by high-temperature susceptibility data......The phase transition of U2Zn17 at 9.7K has been investigated by neutron powder diffraction. The transition corresponds to the onset of antiferromagnetic order where the U moments are oriented antiparallel to their neighbors within the basal planes and the near neighbor along the c^ axis...

Inhibition of bacterial U(VI) reduction by calcium

International Nuclear Information System (INIS)

Brooks, Scott C.; Fredrickson, Jim K.; Carroll, S. L.; Kennedy, David W.; Zachara, John M.; Plymale, Andrew E.; Kelly, S. D.; Kemner, K. M.; Fendorf, S.

2003-01-01

The rapid kinetics of bacterial U(VI) reduction and low solubility of uraninite (UO2,cr) make this process an attractive option for removing uranium from groundwater. Nevertheless, conditions that may promote or inhibit U(VI) reduction are not well-defined. Recent descriptions of Ca-UO2-CO3 complexes indicate that these species may dominate the aqueous speciation of U(VI) in many environments. We monitored the bacterial reduction of U(VI) in bicarbonate-buffered solution in the presence and absence of Ca. XAFS measurements confirmed the presence of a Ca-U(VI)-CO3 complex in the initial solutions containing calcium. Calcium, at millimolar concentrations (0.45-5 mM), caused a significant decrease in the rate and extent of bacterial U(VI) reduction. Both facultative (Shewanella putrefaciens strain CN32) and obligate (Desulfovibrio desulfuricans, Geobacter sulfurreducens) anaerobic bacteria were affected by the presence of calcium. Reduction of U(VI) ceased when the calculated system Eh re ached -0.046+/- 0.001 V, based on the Ca2UO2(CO3)(3) -- > UO2,cr couple. The results are consistent with the hypothesis that U is a less energetically favorable electron acceptor when the Ca-UO2-CO3 complexes are present. The results do not support Ca inhibition caused by direct interactions with the cells or with the electron donor as the reduction of fumarate or Tc(VII)O-4(-) under identical conditions was unaffected by the presence of Ca

Phenomenology with F-theory S U (5 )

Science.gov (United States)

Leontaris, George K.; Shafi, Qaisar

2017-09-01

We explore the low-energy phenomenology of an F-theory-based S U (5 ) model which, in addition to the known quarks and leptons, contains Standard Model (SM) singlets and vectorlike color triplets and S U (2 ) doublets. Depending on their masses and couplings, some of these new particles may be observed at the LHC and future colliders. We discuss the restrictions by Cabibbo-Kobayashi-Maskawa matrix constraints on their mixing with the ordinary down quarks of the three chiral families. The model is consistent with gauge coupling unification at the usual supersymmetric GUT scale; dimension-five proton decay is adequately suppressed, while dimension-six decay mediated by the superheavy gauge bosons is enhanced by a factor of 5-7. The third generation charged fermion Yukawa couplings yield the corresponding low-energy masses in reasonable agreement with observations. The hierarchical nature of the masses of lighter generations is accounted for via nonrenormalizable interactions, with the perturbative vacuum expectation values (VEVs) of the SM singlet fields playing an essential role.

Konstruktivistički pristup obrazovnom postignuću učenika

OpenAIRE

Gutvajn, Nikoleta

2009-01-01

U savremenoj pedagoškoj literaturi, razlike u obrazovnom postignuću učenika se, veomaretko, proučavaju iz perspektive učenika što je, verovatno, jedan od bitnih razloga zakontinuiranu egzistenciju kategorije „neuspešan učenik”. Cilj našeg istraživanja bio je dase problem školskog neuspeha razmotri iz perspektive učenika koji su pozicionirani kaoneuspešni. Umesto mnogobrojnih pretpostavki istraživača o tome zašto su neki učenicineusp...

7 CFR 51.2732 - U.S. No. 2 Spanish.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. No. 2 Spanish. 51.2732 Section 51.2732... STANDARDS) United States Standards for Grades of Shelled Spanish Type Peanuts Grades § 51.2732 U.S. No. 2 Spanish. “U.S. No. 2 Spanish” consists of shelled Spanish type peanut kernels which may be split or broken...

U-series dating using thermal ionisation mass spectrometry (TIMS)

International Nuclear Information System (INIS)

McCulloch, M.T.

1999-01-01

U-series dating is based on the decay of the two long-lived isotopes 238 U(τ 1/2 =4.47 x 10 9 years) and 235 U (τ 1/2 0.7 x 10 9 years). 238 U and its intermediate daughter isotopes 234 U (τ 1/2 = 245.4 ka) and 230 Th (τ 1/2 = 75.4 ka) have been the main focus of recently developed mass spectrometric techniques (Edwards et al., 1987) while the other less frequently used decay chain is based on the decay 235 U to 231 Pa (τ 1/2 = 32.8 ka). Both the 238 U and 235 U decay chains terminate at the stable isotopes 206 Pb and 207 Pb respectively. Thermal ionization mass spectrometry (TIMS) has a number of inherent advantages, mainly the ability to measure isotopic ratios at high precision on relatively small samples. In spite of these now obvious advantages, it is only since the mid-1980's when Chen et al., (1986) made the first precise measurements of 234 U and 232 Th in seawater followed by Edwards et al., (1987) who made combined 234 U- 230 Th measurements, was the full potential of mass spectrometric methods first realised. Several examples are given to illustrate various aspects of TIMS U-series

Optical pulsations from 4U 0900--40: Do they exist

International Nuclear Information System (INIS)

Nelson, J.; Middleditch, J.; Cordova, F.

1979-01-01

A search for optical pulsations from 4U 0900--40 (HD 77581) was made in 1977--1978 using Hβ interference filters. No pulsations were detected above 10 -3 of the observed flux. This contrasts with Steiner's detection of pulsatons at the 2% level. Ariel 5 data covering both our observations and Steiner's show that X-ray variability does not support this decrepancy

The effect of U3O-8 addition on the UO2 pellet

International Nuclear Information System (INIS)

Indrati, Y.T.; Syarif, D. G.; Handayani, A.

1998-01-01

The purpose of varied U 3 O 8 addition on the UO 2 pellet fabrication is to from 1-3 mu pores. The green pellets, compacted with 3 ton/cm 2 , are a mixture powder of UO 2 , TiO 2 (0.1% weight) and varied U 3 O 8 (0-12.5% weight). The green pellets were presintered by H2 atmosphere. The presintered pellets were put on the ceramic crucibles and than those were put on the SS 316 tube with argon atmosphere. The 1400 o C sintering was hold with the soaking time 3 hr and the same rate of heating and cooling 150 o C/hr. The UO 2 pellet with 5% (weight) U 3 O 8 addition has 95.17% of theoretic density and 548.4 ±6.57 VH. Based on the identification of microstructure of pellet, it is not acceptable for nuclear fuel although pellet has 10.02 mu on grain size and 1.3 mu on closed pore size. By the diffractometer X-ray, crystal structure of pellet is face centered cubic (FCC) with the O/U ratio is 2.08

Some comments on flipped SU(5) times U(1) and flipped unification in general

Energy Technology Data Exchange (ETDEWEB)

Barr, S.M. (Bartol Research Institute, University of Delaware, Newark, Delaware 19716 (US))

1989-10-01

A general group-theoretical discussion of flipped embeddings is given. In addition to the well-known flipped SU(5) and flipped SO(10), the existence of flipped E{sub 6} and E{sub 7} is shown, as well as several families and special cases of flipped embeddings. A possible physical reason, essentially based on the group theory of flipped embeddings, why nature prefers the low-energy group SU(3){times}SU(2){times}U(1) to alternatives such as SU(4){times}U(1) and SU(5) is pointed out.

Some comments on flipped SU(5)xU(1) and flipped unification in general

International Nuclear Information System (INIS)

Barr, S.M.

1989-01-01

A general group-theoretical discussion of flipped embeddings is given. In addition to the well-known flipped SU(5) and flipped SO(10), the existence of flipped E 6 and E 7 is shown, as well as several families and special cases of flipped embeddings. A possible physical reason, essentially based on the group theory of flipped embeddings, why nature prefers the low-energy group SU(3)xSU(2)xU(1) to alternatives such as SU(4)xU(1) and SU(5) is pointed out

SU(3)_C× SU(2)_L× U(1)_Y( × U(1)_X ) as a symmetry of division algebraic ladder operators

Science.gov (United States)

Furey, C.

2018-05-01

We demonstrate a model which captures certain attractive features of SU(5) theory, while providing a possible escape from proton decay. In this paper we show how ladder operators arise from the division algebras R, C, H, and O. From the SU( n) symmetry of these ladder operators, we then demonstrate a model which has much structural similarity to Georgi and Glashow's SU(5) grand unified theory. However, in this case, the transitions leading to proton decay are expected to be blocked, given that they coincide with presumably forbidden transformations which would incorrectly mix distinct algebraic actions. As a result, we find that we are left with G_{sm} = SU(3)_C× SU(2)_L× U(1)_Y / Z_6. Finally, we point out that if U( n) ladder symmetries are used in place of SU( n), it may then be possible to find this same G_{sm}=SU(3)_C× SU(2)_L× U(1)_Y / Z_6, together with an extra U(1)_X symmetry, related to B-L.

Periodic light variations of young stars U X Orion and S U Auriga

International Nuclear Information System (INIS)

Minikulov, N.Kh.; Abdulloev, S.Kh.

2007-01-01

The light curves of young variable stars U X Orion and S U Auriga are created from archive data of Institute of Astrophysics of the Academy of Sciences of the Republic of Tajikistan and other sources. It is established that periodic light variations of young stars U X Orion and S U Auriga occurs to duration of 36.4 and 29.8 years, accordingly. It is supposed that such periodic light variations are connected with existence a planetary system around these stars

Comparison of U(VI) adsorption onto nanoscale zero-valent iron and red soil in the presence of U(VI)–CO_3/Ca–U(VI)–CO_3 complexes

International Nuclear Information System (INIS)

Zhang, Zhibin; Liu, Jun; Cao, Xiaohong; Luo, Xuanping; Hua, Rong; Liu, Yan; Yu, Xiaofeng; He, Likai

2015-01-01

Highlights: • NZVI can be used for adsorbing U(VI)–CO_3 complexes. • Use of NZVI is feasible for remediation of uranium-contaminated soils. • The mechanism of U(VI)–CO_3 complexes adsorbing onto NZVI has been explained. - Abstract: The influence of U(VI)–CO_3 and Ca–U(VI)–CO_3 complexes on U(VI) adsorption onto red soil and nanoscale zero-valent iron (NZVI) was investigated using batch adsorption and fixed-bed column experiments to simulate the feasibility of NZVI as the reactive medium in permeable- reactive barriers (PRB) for in situ remediation of uranium-contaminated red soils. The adsorption capacity (q_e) and distribution constant (K_d) of NZVI and red soil decreased with increasing pH, dissolved carbonate and calcium concentrations, but the q_e and K_d values of NZVI were 5–10 times higher than those of red soil. The breakthrough pore volume (PV) values increased with the decrease of pH, dissolved carbonate and calcium concentration; however, the breakthrough PV values of the PRB column filled with 5% NZVI were 2.0–3.5 times higher than the 100% red soil column. The U(VI)–CO_3 complexes adsorbed onto the surface of red soil/NZVI (≡SOH) to form SO–UO_2CO_3"− or SO–UO_2 (CO_3)_2"3"−. XPS and XRD analysis further confirmed the reduction of U(VI) to U(IV) and the formation of FeOOH on NZVI surfaces. The findings of this study are significant to the remediation of uranium-contaminated red soils and the consideration of practical U(VI) species in the natural environment.

Preparations of high density (Th,U)O2 pellets

International Nuclear Information System (INIS)

Akabori, Mitsuo; Ikawa, Katsuichi

1986-07-01

Preparations of high density and homogeneous (Th,U)O 2 pellets by a powder metallurgy method were examined. (Th,U)O 2 powders were prepared by calcining coprecipitates of ammonium uranate and thorium hydroxide derived from nitrates and mixed sols, and by calcining mixed oxalates precipitated from nitrates. (Th,U)O 2 pellets were characterized with respect to sinterability, lattice parameter, microstructure, homogeneity and stoichiometry. Sintering atmospheres had a significant effect upon all the properties of the derived pellets. The sinterability of (Th,U)O 2 was most favourable in oxidizing and reducing atmospheres for ThO 2 -rich and UO 2 -rich compositions, respectively, and can be enhanced by presence of water vapour in sintering atmospheres. In addition, highly homogeneous (Th,U)O 2 pellets with 99 % in theoretical density were derived from the sol powders. (author)

Study of phase transformation of U-2,5Zr-7,5Nb e U-3Zr-9Nb alloys for application in advanced nuclear fuel; Estudo das transformacoes de fases nas ligas U-2,5Zr-7,5Nb e U-3Zr-9Nb para aplicacao em combustivel nuclear avancado

Energy Technology Data Exchange (ETDEWEB)

Pais, Rafael Witter Dias

2015-07-01

Metal fuels are relevant in the nuclear area due to the versatility of its use in the nuclear fuel cycle. Among the alloys of uranium investigated with high potential for use in nuclear power reactors, U-Zr-Nb alloys appear as an important alternative because of their superior physico-chemical and metallurgical properties. These alloys have also potential for use in nuclear testing, research and production radioisotopes of high performance nuclear reactors. Therefore, the development of these alloys is strategic since they are planned to be used in national reactors as RMB (Brazilian Multipurpose Reactor) and LABGENE (Electrical Generation Core Laboratory), currently under development in Brazil. In this work it was realized a extensive study in the scope of the manufacturing, heat treatment and phase transformations of U-2,5Zr-7,5Nb (m/m%) and U-3ZR-9NB (m/m%) fuel alloys. Ingots of both alloys were produced employing a specific methodology developed in this study. This methodology comprised the melting process in a vacuum induction furnace at high temperatures (1500 °C) and thermal-mechanical processing to break the as-cast structure. Samples with typical dimensions (17 x 7 x 2.5 mm) free from macrostructural defects were homogenized at 1000 °C in vacuum of 10{sup -5} torr for 17.5 hours with a 10°C/min cooling rate until to 820 °C and, subsequently, quenched in water. The samples, randomly selected, were subjected to isothermal treatment tests under different conditions of time and temperature. Isothermal treatments for transformation and retention phases were carried out in a special assembly designed for this work. After the tests, the samples were characterized by the usual phase characterization techniques with particular emphasis for the X-ray diffraction technique. In this way, the Rietveld refinement method was applied. In the case of uranium based alloys it is quite challenging due to the lack of data in the literature. In this work a strategy for the

Dissolution behaviour of 238U, 234U and 230Th deposited on filters from personal dosemeters

International Nuclear Information System (INIS)

Beckova, V.; Malatova, I.

2008-01-01

Kinetics of dissolution of 238 U, 234 U and 230 Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultra-filtrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolni Rozinka' at Rozna, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h -1 and the sampling period is typically 1 month. Studied filters contained 125 ± 6 mBq 238 U in equilibrium with 234 U and 230 Th; no 232 Th series nuclides were found. Half-time of rapid dissolution of 1.4 d for 238 U and 234 U and slow dissolution half-times of 173 and 116 d were found for 238 U and 234 U, respectively. No detectable dissolution of 230 Th was found. (authors)

Online Manufacturing Training. ToolingU Review (U)

Energy Technology Data Exchange (ETDEWEB)

Montano, Joshua Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-03-23

The following report is a review of ToolingU, an online manufacturing training website. ToolingU provided the author with a trail account where a number of courses were taken and the overall program was evaluated. A review of the classes revealed that most of the offerings directly align with work at the Laboratory. Ease of use, effectiveness of the system and price all make ToolingU an attractive option for manufacturing training needs.

Study of physical, chemical and electronic properties of binaries and ternaries uranium compounds in the U-Si-B and U-Pt-Si systems

International Nuclear Information System (INIS)

Brisset, Nicolas

2016-01-01

Two main research axes were defined for this Ph-D work: (i) studying the effect of light elements (B, C) on the stability of U-Si compounds, and (ii) identifying and physically characterizing new phases in the U-Pt-Si system. Minor additions of carbon and boron in U-Si samples revealed that the formation of U 5 Si 4 would be correlated to the presence of these light elements, questioning its existence in the U-Si system. To evaluate the boron potential as a stimulant for non-metallic light elements of the second period (C, N, O), the isothermal section of the ternary phase diagram U-Si-B has been drawn at 927 C, disclosing solid equilibrium mainly between the UB and U-Si binary axes and the existence of the novel compound U 20 Si 16 B 3 , isostructural to the carbon equivalent one. These results suggest a specific behavior for a given light element on the U-Si phase relations. The isothermal section at 900 C of the U-Pt-Si ternary system was experimentally determined, leading to the discovery of 14 new phases, among which U 3 Pt 4 Si 6 , U 3 Pt 6 Si 4 and U 3 Pt 7 Si crystallized in their own structural type. As a prerequisite for this study, the phase relations in the U-Pt binary phase diagram were re-examined for the composition range 30 at.% and 70 at.% Pt, leading to a new assessment of the phase diagram which comprises the new U 3 Pt 4 compound. The temperature of the transformations has been measured by DTA. By coupling our experimental results to the literature data, a modeling of the phase diagram by the Calphad method was performed. Physical characterizations of the new U 3 Pt 4 compound revealed a moderate heavy fermion behavior, with ferromagnetic ordering below Tc = 7(1) K. As a side project, a study of the U 3 TGe 5 family with the anti-Hf 5 CuSn 3 structural type lead to the discovery of nine new compounds for T = V, Cr, Mn, Zr, Nb, Mo, Hf, Ta and W in addition to the previously reported U 3 TiGe 5 . Their magnetic and electronic properties were

Physico-chemical properties of (U,Ce)O2

International Nuclear Information System (INIS)

Yamada, K.; Yamanaka, S.; Katsura, M.

1998-01-01

The high-temperature X-ray diffraction analysis of (U,Ce)O 2 with CeO 2 contents ranging from 0 to 20 mol.% CeO 2 was performed to obtain the variation of the linear thermal expansion coefficient with the CeO 2 content. Ultrasonic pulse-echo measurements were also carried out from room temperature to 673 K to estimate the change in the mechanical properties of (U,Ce)O 2 with the CeO 2 content. The variation in the linear thermal expansion coefficient at the low CeO 2 content region is more steep than that expected from the linear thermal expansion coefficient of UO 2 and CeO 2 . The Young's and shear moduli of all (U,Ce)O 2 were found to decrease with rising temperature. This was due to the increase of the bond length accompanied by the thermal expansion. Although the lattice parameter decreased with CeO 2 content, the moduli of (U,Ce)O 2 were found to decrease with increasing CeO 2 content at room temperature. These results show that in the range from 0 to 20 mol.% of CeO 2 , as CeO 2 content increases, the bottom of the potential energy in (U,Ce)O 2 is shallower and broader. (orig.)

4U 1909+07: a Hidden Pearl

Directory of Open Access Journals (Sweden)

I. Kreykenbohm

2011-01-01

Full Text Available We present a detailed spectral and timing analysis of the High Mass X-ray Binary (HMXB 4U 1909+07 with INTEGRAL and RXTE. 4U1909+07 is a persistent accreting X-ray pulsar with a period of approximately 605 s. The period changes erratically consistent with a random walk expected for a wind accreting system. INTEGRAL detects the source with an average of 2.4 cps (corresponding to 15mCrab, but sometimes exhibits flaring activity up to 50 cps (i.e. 300mCrab. The strongly energy dependent pulse profile shows a double peaked structure at low energies and only a single narrow peak at energies above 20 keV. The phase averaged spectrum is well described by a powerlaw modified at higher energies by an exponential cutoff and photoelectric absorption at low energies. In addition at 6.4 keV a strong iron fluorescence line and at lower energies a blackbody component are present. We performed phase resolved spectroscopy to study the pulse phase dependence of the spectral parameters: while most spectral parameters are constant within uncertainties, the blackbody normalization and the cutoff folding energy vary strongly with phase.

Contribution to the study of U-Ti and U-Pu-Ti carbides; Contribution a l'etude des carbures U-C-Ti et (U, Pu) - C-Ti

Energy Technology Data Exchange (ETDEWEB)

Milet, C A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1968-07-01

After having discussed the reasons to use (U,Pu) carbides as fast reactor fuel, we examine the influence of the addition of titanium to these carbides. A preliminary study has been done on the system of U-C-Ti and some properties have been measured such as: density, thermal expansion, electrical resistivity, atmospheric corrosion and compatibility with stainless steel. The systems U-Pu-C-Ti (Pu/U + Pu equal to 15 per cent) and U-C-Ti have been found to be very similar. There exists a two phases region (U,Pu)C + TiC, an eutectic between (U,Pu)C and TiC for approximately 15 at %. The solubilities of U + Pu in TiC and of Ti in (U,Pu)C is less than 1 % at. The addition of titanium does not markedly change thermal expansion coefficients of (U,Pu)C. However the resistance to atmospheric corrosion and compatibility with stainless steel is improved. Thermal conductivity, calculated from electrical resistivity, has increased. On the other side, the density of fissile material is lowered. The combination of (U,Pu)C + TiC seems to be the most promising alloy for application as nuclear fuel. (author) [French] Apres avoir rappele les problemes poses par un combustible pour les reacteurs a neutrons rapides et l'interet des carbures U-Pu-C comme combustible, on examine l'influence de l'addition de titane dans ces carbures. Une etude preliminaire sur le systeme U-C-Ti a ete effectuee et quelques proprietes sont indiquees: densite, coefficients de dilatation, resistivite electrique, tenue a la corrosion atmospherique, compatibilite avec l'acier inoxydable. Le systeme U-Pu-C-Ti (Pu/U + Pu egal a 15 pour cent) presente de grandes analogies avec le systeme U-C-Ti. Il existe un domaine biphase (U,Pu)C + TiC, un eutectique entre (U,Pu)C et TiC pour environ 15 at % Ti; les solubilites de U + Pu clans TiC et de Ti dans (U,Pu)C sont inferieures a 1 at %. Par rapport a la phase (U,Pu)C, l'addition de titane est sans effets importants sur les coefficients de dilatation. Par contre la tenue a

Dicty_cDB: Contig-U15323-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U15323-1 no gap 1230 2 3760829 3759661 MINUS 76 108 U15323 2 0 21 0 9 4 0 0 22 4 13 0 1 0 Show Contig...-U15323-1 Contig ID Contig-U15323-1 Contig update 2004. 6.11 Contig sequence >Contig-U15323-1 (Contig-U15323-1Q) /CSM_Contig/Contig-U1532...TAAAATTTAAGCAATCATTCCAT Gap no gap Contig length 1230 Chromosome number (1..6, M) 2 Chromosome length 846757...VGLLVFFNILYCTPLYYILFFFKMNSKFADELIATAKAIVAPGKGILAADESTNTIGAR FKKINLENNEENRRAYRELLIGTGNGVNEFIGGIILYEETLYQKMADG...MNSKFADELIATAKAIVAPGKGILAADESTNTIGAR FKKINLENNEENRRAYRELLIGTGNGVNEFIGGIILYEETLYQK

Evolution of tidal capture X-ray binaries - 4U 2127+12 (M15) to 4U 1820-30 (NGC 6624)

International Nuclear Information System (INIS)

Bailyn, C.D.; Grindlay, J.E.

1987-01-01

A new evolutionary scenario for X-ray binaries in globular clusters, which begins with a tidal capture of a main-sequence star by a neutron star and ends with a white dwarf-neutron star system, is presented. For tidal captures of main-sequence stars into orbits too wide to begin mass transfer immediately, the subsequent evolution of the secondary can lead to a common envelope binary similar to what the 9 hr X-ray binary 4U 2127+12 in M15 is suspected to be. If the common envelope is thick enough, it may cause the neutron star and the white dwarf core of the secondary to spiral in, producing a detached white dwarf-neutron star system. Subsequently, gravitational radiation losses may evolve this into the configuration seen in the 11 minute X-ray binary 4U 1820-30 in NGC 6624. This model appears more likely on statistical grounds than formation by collision of a neutron star and a red giant. In some circumstances, the latter process may result in unstable mass transfer, which would result in coalescence rather than a binary system like 4U 1820-30. 34 references

Tetragonal phase in Al-rich region of U-Fe-Al system

International Nuclear Information System (INIS)

Meshi, L.; Zenou, V.; Ezersky, V.; Munitz, A.; Talianker, M.

2005-01-01

A new ternary aluminide U 2 FeAl 20 with the approximate composition Al-4.2at% Fe-8.5at% U was observed in the Al-rich corner of the U-Al-Fe system. Transmission electron microscopy and electron microdiffraction technique were used for characterization of the structure of this phase. It has a tetragonal unit cell with the parameters a=12.4A and c=10.3A and can be described by the space group I4-bar 2m

The determination of molar volumes of uranous nitrate and nitric acid in systems of U(NO3)4-HNO3-H2O and U(NO3)4-HNO3-30% TBP kerosene

International Nuclear Information System (INIS)

Tao Chengying

1986-01-01

The data of molar volumes of uranous nitrate and nitric acid are necessary for the calculation of the changes in phase volume during the extraction in U(NO 3 ) 4 -HNO 3 /30%TBP-kerosene system. However, the data of the partial molar volume of U(NO 3 ) 4 are not available in literature. In the present work, the molar volumes of U(NO 3 ) 4 and HNO 3 are calculated by linear fitting of the experimental data. The result of the molar volume of HNO 3 is consistent with those in literature

Water-Reflected 233U Uranyl Nitrate Solutions in Simple Geometry

International Nuclear Information System (INIS)

Elam, K.R.

2001-01-01

A number of critical experiments involving 233 U were performed in the Oak Ridge National Laboratory Building 9213 Critical Experiments Facility during the years 1952 and 1953. These experiments, reported in Reference 1, were directed toward determining bounding values for the minimum critical mass, minimum critical volume, and maximum safe pipe size of water-moderated solutions of 233 U. Additional information on the critical experiments was found in the experimental logbooks. Two experiments utilizing uranyl nitrate (UO 2 (NO 3 ) 2 ) solutions in simple geometry are evaluated in this report. Experiment 37 is in a 10.4-inch diameter sphere, and Experiment 39 is in a 10-inch diameter cylinder. The 233 U concentration ranges from 49 to 62 g 233 U/l. Both experiments were reflected by at least 6 inches of water in all directions. Paraffin-reflected uranyl nitrate experiments, also reported in Reference 1, are evaluated elsewhere. Experiments with smaller paraffin reflected 5-, 6-, and 7.5-inch diameter cylinders are evaluated in U233-SOL-THERM-004. Experiments with paraffin reflected 8-, 8.5-, 9-, 10-, and 12-inch diameter cylinders are evaluated in U233-SOL-THERM-002. Later experiments with highly-enriched 235 U uranyl fluoride solution in the same 10.4-inch diameter sphere are reported in HEU-SOL-THERM-010. Both experiments were judged acceptable for use as criticality-safety benchmark experiments

Dissolution behaviour of 238U, 234U and 230Th deposited on filters from personal dosemeters.

Science.gov (United States)

Becková, Vera; Malátová, Irena

2008-01-01

Kinetics of dissolution of (238)U, (234)U and (230)Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultrafiltrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolní Rozínka' at Rozná, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h(-1) and the sampling period is typically 1 month. Studied filters contained 125 +/- 6 mBq (238)U in equilibrium with (234)U and (230)Th; no (232)Th series nuclides were found. Half-time of rapid dissolution of 1.4 d for (238)U and (234)U and slow dissolution half-times of 173 and 116 d were found for (238)U and (234)U, respectively. No detectable dissolution of (230)Th was found.

Collective and single-particle excitations in the heavy deformable nuclei 234U, 233U, 231Th, 230Pa and 232Pa

International Nuclear Information System (INIS)

Kotthaus, Tanja

2010-01-01

In this thesis five heavy deformed isotopes from the mass region A≥230, namely 234 U, 233 U, 231 Th, 230 Pa and 232 Pa, were investigated by means of deuteron-induced neutron transfer reactions. The even-even isotope 234 U has been studied with the 4π-γ-spectrometer MINIBALL at the Cologne Tandem accelerator. Excited nuclei in the isotope 234 U were produced using the reaction 235 U(d,t) at a beam energy of 11 MeV. The target thickness was 3.5 mg/cm 2 . The analysis of the γγ-coincidence data yielded a reinterpretation of the level scheme in 12 cases. Considering its decay characteristics, the 4 + state at an excitation energy of 1886.7 keV is a potential candidate for a two-phonon vibrational state. The isotopes 233 U, 231 Th, 230 Pa and 232 Pa were investigated at the Munich Q3D spectrometer. For each isotope an angular distribution with angles between 5 and 45 were measured. In all four cases the energy of the polarized deuteron beam (vector polarization of 80%) was 22 MeV. As targets 234 U (160 μg/cm 2 ), 230 Th (140 μg/cm 2 ) and 231 Pa (140 μg/cm 2 ) were used. The experimental angular distributions were compared to results of DWBA calculations. For the odd isotope 233 U spin and parity for 33 states are assigned and in the other odd isotope 231 Th 22 assignments are made. The excitation spectra of the two odd-odd isotopes 230 Pa and 232 Pa were investigated for the first time. For the isotope 230 Pa 63 states below an excitation energy of 1.5 MeV are identified. Based on the new experimental data the Nilsson configuration of the ground state is either 1/2[530] p -5/2[633] n or 1/2[530] p +3/2[631] n . In addition 12 rotational bands are proposed and from this six values for the GM splitting energy are deduced as well as two new values for the Newby shift. In the other odd-odd isotope 232 Pa 40 states below an excitation energy of 850 keV are observed and suggestions for the groundstate band and its GM partner are made. From this one GM splitting

7 CFR 51.1147 - U.S. No. 2 Bright.

Science.gov (United States)

2010-01-01

...) Internal quality: Lots meeting the internal requirements for “U.S. Grade AA Juice (Double A)” or “U.S... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. No. 2 Bright. 51.1147 Section 51.1147 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...

Voltametric determination of O:U relation in uranium oxide

International Nuclear Information System (INIS)

Carvalho, F.M.S. de; Abrao, A.

1988-07-01

Uranium oxide samples are dissolved in hot concentrated H 3 PO 4 - H 2 SO 4 mixture and the solution diluted with 1M H 2 SO 4 . One aliquot of such solution (A) is used to record the first voltamogram which gives the U(VI) content. To a second aliquot HNO 3 and H 2 O 2 is added to oxidise uranium to the hexavalent state (B) and the second voltamogram is recorded from 0.0 to 0.4 V X SCE. The O:U ratio in the original sample is calculated by the expression: O/U = 2.000 + [U (VI) soln.A/% U(VI) soln. B]. The method provides an accurate means for determining O to U ratios in high-purity uranium dioxide, fuel pellets and a variety of oxides prepared for developmental work on ceramic fuel materials. (author) [pt

Reply to Comment on "Zircon U-Th-Pb dating using LA-ICP-MS: Simultaneous U-Pb and U-Th dating on the 0.1 Ma Toya Tephra, Japan"

Science.gov (United States)

Ito, Hisatoshi

2015-04-01

Guillong et al. (2015) mentioned that corrections for abundance sensitivity for 232Th and molecular zirconium sesquioxide ions (Zr2O3+) are critical for reliable determination of 230Th abundances in zircon for LA-ICP-MS analyses. There is no denying that more rigorous treatments are necessary to obtain more reliable ages than those in Ito (2014). However, as shown in Fig. 2 in Guillong et al. (2015), the uncorrected (230Th)/(238U) for reference zircons except for Mud Tank are only 5-20% higher than unity. Since U abundance of Toya Tephra zircons that have U-Pb ages Ito (2014) obtained U-Th ages of the Toya Tephra by comparison with Fish Canyon Tuff (FCT) data. Because both the FCT and the Toya Tephra have similar trends of overestimation of 230Th, the effect of overestimation of 230Th to cause overestimation of U-Th age should be cancelled out or negligible. Therefore the pivotal conclusion in Ito (2014) that simultaneous U-Pb and U-Th dating using LA-ICP-MS is possible and useful for Quaternary zircons holds true.

Local U(2,2) Symmetry in Relativistic Quantum Mechanics

OpenAIRE

Finster, Felix

1997-01-01

Local gauge freedom in relativistic quantum mechanics is derived from a measurement principle for space and time. For the Dirac equation, one obtains local U(2,2) gauge transformations acting on the spinor index of the wave functions. This local U(2,2) symmetry allows a unified description of electrodynamics and general relativity as a classical gauge theory.

Local U(2,2) symmetry in relativistic quantum mechanics

Science.gov (United States)

Finster, Felix

1998-12-01

Local gauge freedom in relativistic quantum mechanics is derived from a measurement principle for space and time. For the Dirac equation, one obtains local U(2,2) gauge transformations acting on the spinor index of the wave functions. This local U(2,2) symmetry allows a unified description of electrodynamics and general relativity as a classical gauge theory.

Cooling rates and the depth of detachment faulting at oceanic core complexes: Evidence from zircon Pb/U and (U-Th)/He ages

Science.gov (United States)

Grimes, Craig B.; Cheadle, Michael J.; John, Barbara E.; Reiners, P.W.; Wooden, J.L.

2011-01-01

Oceanic detachment faulting represents a distinct mode of seafloor spreading at slow spreading mid-ocean ridges, but many questions persist about the thermal evolution and depth of faulting. We present new Pb/U and (U-Th)/He zircon ages and combine them with magnetic anomaly ages to define the cooling histories of gabbroic crust exposed by oceanic detachment faults at three sites along the Mid-Atlantic Ridge (Ocean Drilling Program (ODP) holes 1270D and 1275D near the 15??20???N Transform, and Atlantis Massif at 30??N). Closure temperatures for the Pb/U (???800??C-850??C) and (U-Th)/He (???210??C) isotopic systems in zircon bracket acquisition of magnetic remanence, collectively providing a temperature-time history during faulting. Results indicate cooling to ???200??C in 0.3-0.5 Myr after zircon crystallization, recording time-averaged cooling rates of ???1000??C- 2000??C/Myr. Assuming the footwalls were denuded along single continuous faults, differences in Pb/U and (U-Th)/He zircon ages together with independently determined slip rates allow the distance between the ???850??C and ???200??C isotherms along the fault plane to be estimated. Calculated distances are 8.4 ?? 4.2 km and 5.0 2.1 km from holes 1275D and 1270D and 8.4 ?? 1.4 km at Atlantis Massif. Estimating an initial subsurface fault dip of 50 and a depth of 1.5 km to the 200??C isotherm leads to the prediction that the ???850??C isotherm lies ???5-7 km below seafloor at the time of faulting. These depth estimates for active fault systems are consistent with depths of microseismicity observed beneath the hypothesized detachment fault at the TAG hydrothermal field and high-temperature fault rocks recovered from many oceanic detachment faults. Copyright 2011 by the American Geophysical Union.

Limitations on the precision of 238U/235U measurements and implications for environmental monitoring

International Nuclear Information System (INIS)

Russ III, G.P.

1997-01-01

The ability to determine the isotopic composition of uranium in environmental samples is an important component of the International Atomic Energy Agency's (IAEA) safeguards program, and variations in the isotopic ratio 238 U/ 235 U provide the most direct evidence of isotopic enrichment activities. The interpretation of observed variations in 238 U/ 235 U depends on the ability to distinguish enrichment from instrumental biases and any variations occurring in the environment but not related to enrichment activities. Instrumental biases that have historically limited the accuracy of 238 U/ 235 U determinations can be eliminated by the use of the 233 U/ 236 U double-spike technique. With this technique, it is possible to determine the 238 U/ 235 U in samples to an accuracy equal to the precision of the measurement, ca. 0.1% for a few 10's of nanograms of uranium. Given an accurate determination of 238 U/ 235 U, positive identification of enrichment activities depends on the observed value being outside the range of 238 U/ 235 U's expected as a result of natural or environmental variations. Analyses of a suite of soil samples showed no variation beyond 0.2% in 238 U/ 235 U

Dicty_cDB: Contig-U12316-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U12316-1 gap included 1238 4 1925901 1927143 PLUS 5 6 U12316 0 4 1 0 0 0 0 0 0 0 0 0 0 0 Show Contig...-U12316-1 Contig ID Contig-U12316-1 Contig update 2002.12.18 Contig sequence >Contig-U12316-1 (Contig-U12316-1Q) /CSM_Contig/Contig-U12316...GAGTTGAAGATTTAGTTTTATCAGNANGAANAAATAAGAT Gap gap included Contig length 1238 Chromosome number (1..6, M) 4 C...,915,1174 Translated Amino Acid sequence lvqhhyh*liscvivllksmv*isqvhivvhlfmfvn*qyileih*iptlknlskiftig...lip*r*rtrkttn*kiknny*itketkiqs*t*rvmmmi*vedlvls xxxnk Frame B: lvqhhyh*liscvivllksmv*isqvhivvhlfmfvn*qyileih*iptlknlskiftig

Hidden U$_{q}$(sl(2)) x U$_{q}$(sl(2)) quantum group symmetry in two dimensional gravity

CERN Document Server

Cremmer, E; Schnittger, J

1997-01-01

In a previous paper, we proposed a construction of U_q(sl(2)) quantum group symmetry generators for 2d gravity, where we took the chiral vertex operators of the theory to be the quantum group covariant ones established in earlier works. The basic idea was that the covariant fields in the spin 1/2 representation themselves can be viewed as generators, as they act, by braiding, on the other fields exactly in the required way. Here we transform this construction to the more conventional description of 2d gravity in terms of Bloch wave/Coulomb gas vertex operators, thereby establishing for the first time its quantum group symmetry properties. A U_q(sl(2))\\otimes U_q(sl(2)) symmetry of a novel type emerges: The two Cartan-generator eigenvalues are specified by the choice of matrix element (bra/ket Verma-modules); the two Casimir eigenvalues are equal and specified by the Virasoro weight of the vertex operator considered; the co-product is defined with a matching condition dictated by the Hilbert space structure of...

Decay scheme of the U{sup 2}35; Esquema de desintegracion del U-235

Energy Technology Data Exchange (ETDEWEB)

Gaeta, R

1965-07-01

A study of the Th{sup 2}31 excited levels from the alpha decay of the U{sup 2}35, is carried out. The alpha particle spectrum was measured by means of a semiconductor counter spectrometer with an effective resolution of 18 keV. Nineteen new lines were identified. The gamma-ray spectrum was measured with thin samples of U{sup 2}35, free from decay products, and in such geometrical conditions, that most of the interference effects were eliminated. The gamma-gamma coincidence spectra have made easier a better knowledge of the transition between the several levels. (Author) 110 refs.

First TREAT transient overpower tests on U-Pu-Zr fuel: M5 and M6

International Nuclear Information System (INIS)

Robinson, W.R.; Bauer, T.H.; Wright, A.E.; Rhodes, E.A.; Stanford, G.S.; Klickman, A.E.

1987-01-01

Transient Reactor Test Facility (TREAT) tests M5 and M6 were the first transient overpower (TOP) test of the margin to cladding breach and prefailure elongation of metallic U-Pu-Zr ternary fuel, the reference fuel of the integral fast reactor concept. Similar tests on U-5 wt% Fs fueled Experimental Breeder Reactor (EBR)-II driver pins were previously performed and reported. Results from these earlier tests indicated a margin to failure of ∼ 4 times nominal power and significant axial elongation prior to failure, a feature that was very pronounced at low burnups. While these two fuels types are similar in many respects, the ternary alloy exhibits a much more complex physical structure and is typically irradiated at much higher temperatures. Thus, a prime motivation for performing M5 and M6 was to compare the safety-related fuel performance characteristics of U-Fs and U-Pu-Zr. Tests M5 and M6 indicate that, under the TOP conditions used in the tests, ternary fuel displayed about the same margin to failure as U-Fs fuel. At low burnups, ternary fuel showed less prefailure axial elongation than observed in U-Fs pins, but elongations of 3 to 5% might turn out to be typical. Finally, fuel from the breached ternary pin in M6 showed, qualitatively, the same benignly dispersive behavior as U-Fs

Dicty_cDB: Contig-U15462-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available Contig-U15462-1 no gap 546 4 3384206 3383661 MINUS 2 2 U15462 0 0 2 0 0 0 0 0 0 0 0 0 0 0 Show Contig...-U15462-1 Contig ID Contig-U15462-1 Contig update 2004. 6.11 Contig sequence >Contig-U15462-1 (Contig...-U15462-1Q) /CSM_Contig/Contig-U15462-1Q.Seq.d CTTTAGATTGGGGNTCAAGAAAAATATTGAAGTATTTGGTGGTGATAAGA...ATTCGATTCACTATCTTATA Gap no gap Contig length 546 Chromosome number (1..6, M) 4 Chromosome length 5430582 St...VMKLGFEVKDLITNDPKCDLFDSLS Y own update 2004. 6.23 Homology vs CSM-cDNA Query= Contig-U15462-1 (Contig

Thermal compatibility of U-2wt.%Mo and U-10wt.%Mo fuel prepared by centrifugal atomization for high density research reactor fuels

International Nuclear Information System (INIS)

Kim Ki Hwan; Lee Don Bae; Kim Chang Kyu; Kuk Il Hyun; Hofman, G.E.

1997-01-01

Research on the intermetallic compounds of uranium was revived in 1978 with the decision by the international research reactor community to develop proliferation-resistant fuels. The reduction of 93% 235 U (HEU) to 20% 235 U (LEU) necessitates the use of higher U-loading fuels to accommodate the addition 238 U in the LEU fuels. While the vast majority of reactors can be satisfied with U 3 Si 2 -Al dispersion fuel, several high performance reactors require high loadings of up to 8-9 g U cm -3 . Consequently, in the renewed fuel development program of the Reduced Enrichment for Research and Test Reactors (RERTR) Program, attention has shifted to high density uranium alloys. Early irradiation experiments with uranium alloys showed promise of acceptable irradiation behavior, if these alloys can be maintained in their cubic γ-U crystal structure. It has been reported that high density atomized U-Mo powders prepared by rapid cooling have metastable isotropic γ-U phase saturated with molybdenum, and good γ-U phase stability, especially in U-10wt.%Mo alloy fuel. If the alloy has good thermal compatibility with aluminium, and this metastable gamma phase can be maintained during irradiation, U-Mo alloy would be a prime candidate for dispersion fuel for research reactors. In this paper, U-2w.%Mo and U-10w.%Mo alloy powder which have high density (above 15 g-U/cm 3 ), are prepared by centrifugal atomization. The U-Mo alloy fuel meats are made into rods extruding the atomized powders. The characteristics related to the thermal compatibility of U-2w.%Mo and U-10w.%Mo alloy fuel meat at 400 o C for time up to 2000 hours are examined. (author)

238U, 234U and 230Th in uranium miners' lungs

International Nuclear Information System (INIS)

Singh, M.P.; Wrenn, M.E.; Archer, V.E.; Saccomanno, G.

1981-01-01

Fourteen uranium miners' lungs from Colorado plateau were collected at autopsy and the concentrations of 238 U, 234 U and 230 Th were determined by radiochemical procedures utilizing solvent extraction - alpha spectrometric techniques. The uranium and thorium isotopes are in near equilibrium with average concentrations of 238 U, 234 U and 230 Th being 89.3, 95.2 and 91.1 pCi/kg respectively. The combined average radiation dose rate to lung from these three isotopes is about 24.2 mrad/year at death excluding the unmeasured contribution from the 226 Ra and daughters. The average concentration of 230 Th is about 65 times higher than the mean concentration of 230 Th in lungs of non-miners dying at comparable ages from the same region

First-principles investigation of U doping in ZrO2

International Nuclear Information System (INIS)

Huang, H.W.; Pan, Y.; Yu, C.; Yang, J.; Wang, H.; Yi, W.; Peng, J.C.

2014-01-01

Highlights: • U-doped system with cubic structure is more stable than the monoclinic structure. • The elastic modulus of cubic structure is higher than the monoclinic structure. • U-doped weakens the resistance to shear deformation of ZrO 2 . • U-doped enhances the resistance to shape deformation for monoclinic structure. -- Abstract: The formation energies, elastic properties, Debye temperature and electronic structure of U-doped ZrO 2 within cubic and monoclinic structures are investigated by first-principles approach. The calculated formation energies show that the U-doped with cubic structure is more stable than that of monoclinic structure. The U-doped weakens the resistance to shear deformation whether cubic structure or monoclinic structure. However, the U-doped decreases the shape deformation of cubic structure in contrast to enhances the shape deformation for monoclinic structure. The Debye temperature of U-doped system is lower than the corresponding ZrO 2 . We found that the calculated electronic structure of these systems are consistent with the variation of formation energies

On hyperbolic U4 manifolds with local duality

International Nuclear Information System (INIS)

Wallner, R.P.

1982-01-01

We use the decomposition of the Riemann/Cartan curvature 2-forms Ωsup(ij) in terms of their irreducible parts under the Lorentz group to examine the irreducible content of self- and anti-self double dual curvature forms Ωsup(+-ij) and their further refinements involving left and right duals. In the case of local duality (i.e. Ωsup(ij) = Ωsup(+-ij) locally), some consequences to curvature and torsion are easily derived in this way. As Riemann/Cartan space-times (U 4 -space-times) are subject to generalized gravity theories, some (vacuum) field equations proposed there are also taken into considerations. As an application to the various decompositions of curvature and torsion we point out their utility in the search of exact solutions of U 4 -field equations. To simplify notations and calculations, the calculus of exterior forms is used throughout. (Author)

Stem cell survival is severely compromised by the thymidineanalog EdU (5-ethynyl-2'-deoxyuridine), an alternative to BrdU for proliferation assays and stem cell tracing

DEFF Research Database (Denmark)

Andersen, Ditte C; Skovrind, Ida; Christensen, Marlene Louise

2013-01-01

Stem cell therapy has opened up the possibility of treating numerous degenerating diseases. However, we are still merely at the stage of identifying appropriate sources of stem cells and exploring their full differentiation potential. Thus, tracking the stem cells upon in vivo engraftment...... and during in vitro co-culture is very important and is an area of research embracing many pitfalls. 5-Ethynyl-2'-deoxyuridine (EdU), a rather new thymidine analog incorporated into DNA, has recently been suggested to be a novel highly valid alternative to other dyes for labeling of stem cells and subsequent...... tracing of their proliferation and differentiation ability. However, our results herein do not at any stage support this recommendation, since EdU severely reduces the viability of stem cells. Accordingly, we found that transplanted EdU-labeled stem cells hardly survive upon in vivo transplantation...

Colorimetric on-line control of U

International Nuclear Information System (INIS)

Perez, J.J.; Boisde, G.; Dedaldechamp, P.; Dureault, B.

The instrumentation developed for the automatic colorimetric control of U is presented. Two techniques are used: absorptiometry of U ions using optical probes enabling to measure in situ the solutions containing 0.5 g U(IV)/l or 1 g U(VI)/l; colorimetry of the U-DBM complexe after separation of U by TOPO (this technique is applied to the control of U at the ppm level). The automatic devices used are described. They are experimented in laboratory or in pilot-plant [fr

Irradiation behaviour of solid and hollow U{sub 3}Si fuel elements: results to 15,000 MWd/tonne U

Energy Technology Data Exchange (ETDEWEB)

Feraday, M A; Chalder, G H; Cotnam, K D

1969-06-15

U{sub 3}Si fuel elements clad in zirconium alloy sheaths have been irradiated to burnups close to 15,000 MWd/tonne U in pressurized water at 220{sup o}C, 98 bars. The results show that the external swelling can be controlled by incorporating free volume in the element. The dimensional stability of such elements is adequate to permit their use in power reactor fuel bundles. A diameter increase of 1.2% had occurred in an element initially containing 12.8% total free volume, after a burnup of 14,700 MWd/tonne U. There was no change in diameter between burnups of 5200 and 14,700 MWd/tonne U. Elements containing 3% total free volume had increased in diameter about 2.5% at 2000 MWd/tonne U compared to 0.2% at 9500 MWd/tonne U for elements containing 22% total free volume. The observed swelling in the U{sub 3}Si is discussed in terms of possible mechanisms. (author)

Reaction kinetics aspect of U3O8 kernel with gas H2 on the characteristics of activation energy, reaction rate constant and O/U ratio of UO2 kernel

International Nuclear Information System (INIS)

Damunir

2007-01-01

The reaction kinetics aspect of U 3 O 8 kernel with gas H 2 on the characteristics of activation energy, reaction rate constant and O/U ratio of UO 2 kernel had been studied. U 3 O 8 kernel was reacted with gas H 2 in a reduction furnace at varied reaction time and temperature. The reaction temperature was varied at 600, 700, 750 and 850 °C with a pressure of 50 mmHg for 3 hours in gas N 2 atmosphere. The reation time was varied at 1, 2, 3 and 4 hours at a temperature of 750 °C using similar conditions. The reaction product was UO 2 kernel. The reaction kinetic aspect between U 3 O 8 and gas H 2 comprised the minimum activation energy (ΔE), the reaction rate constant and the O/U ratio of UO 2 kernel. The minimum activation energy was determined from a straight line slope of equation ln [{D b . R o {(1 - (1 - X b ) ⅓ } / (b.t.Cg)] = -3.9406 x 10 3 / T + 4.044. By multiplying with the straight line slope -3.9406 x 10 3 , the ideal gas constant (R) 1.985 cal/mol and the molarity difference of reaction coefficient 2, a minimum activation energy of 15.644 kcal/mol was obtained. The reaction rate constant was determined from first-order chemical reaction control and Arrhenius equation. The O/U ratio of UO 2 kernel was obtained using gravimetric method. The analysis result of reaction rate constant with chemical reaction control equation yielded reaction rate constants of 0.745 - 1.671 s -1 and the Arrhenius equation at temperatures of 650 - 850 °C yielded reaction rate constants of 0.637 - 2.914 s -1 . The O/U ratios of UO 2 kernel at the respective reaction rate constants were 2.013 - 2.014 and the O/U ratios at reaction time 1 - 4 hours were 2.04 - 2.011. The experiment results indicated that the minimum activation energy influenced the rate constant of first-order reaction and the O/U ratio of UO 2 kernel. The optimum condition was obtained at reaction rate constant of 1.43 s -1 , O/U ratio of UO 2 kernel of 2.01 at temperature of 750 °C and reaction time of 3

U-series dating using thermal ionisation mass spectrometry (TIMS)

Energy Technology Data Exchange (ETDEWEB)

McCulloch, M.T. [Australian National University, Canberra, ACT (Australia). Research School of Earth Science

1999-11-01

U-series dating is based on the decay of the two long-lived isotopes{sup 238}U({tau}{sub 1/2}=4.47 x 10{sup 9} years) and {sup 235}U ({tau}{sub 1/2} 0.7 x 10{sup 9} years). {sup 238}U and its intermediate daughter isotopes {sup 234}U ({tau}{sub 1/2} = 245.4 ka) and {sup 230}Th ({tau}{sub 1/2} = 75.4 ka) have been the main focus of recently developed mass spectrometric techniques (Edwards et al., 1987) while the other less frequently used decay chain is based on the decay {sup 235}U to {sup 231}Pa ({tau}{sub 1/2} = 32.8 ka). Both the {sup 238}U and {sup 235}U decay chains terminate at the stable isotopes {sup 206}Pb and {sup 207}Pb respectively. Thermal ionization mass spectrometry (TIMS) has a number of inherent advantages, mainly the ability to measure isotopic ratios at high precision on relatively small samples. In spite of these now obvious advantages, it is only since the mid-1980`s when Chen et al., (1986) made the first precise measurements of {sup 234}U and {sup 232}Th in seawater followed by Edwards et al., (1987) who made combined {sup 234}U-{sup 230}Th measurements, was the full potential of mass spectrometric methods first realised. Several examples are given to illustrate various aspects of TIMS U-series 9 refs., 3 figs.

Inventory of U.S. 2012 dioxin emissions to atmosphere.

Science.gov (United States)

Dwyer, Henri; Themelis, Nickolas J

2015-12-01

In 2006, the U.S. EPA published an inventory of dioxin emissions for the U.S. covering the period from 1987-2000. This paper is an updated inventory of all U.S. dioxin emissions to the atmosphere in the year 2012. The sources of emissions of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), collectively referred to in this paper as "dioxins", were separated into two classes: controlled industrial and open burning sources. Controlled source emissions decreased 95.5% from 14.0 kg TEQ in 1987 to 0.6 kg in 2012. Open burning source emissions increased from 2.3 kg TEQ in 1987 to 2.9 kg in 2012. The 2012 dioxin emissions from 53 U.S. waste-to-energy (WTE) power plants were compiled on the basis of detailed data obtained from the two major U.S. WTE companies, representing 84% of the total MSW combusted (27.4 million metric tons). The dioxin emissions of all U.S. WTE plants in 2012 were 3.4 g TEQ and represented 0.54% of the controlled industrial dioxin emissions, and 0.09% of all dioxin emissions from controlled and open burning sources. Copyright © 2015. Published by Elsevier Ltd.

U-2 Bono sünnipäevapidu

Index Scriptorium Estoniae

2002-01-01

10. mail toimub Guitar Safari pubis Estonian U Fan Clubi eestvedamisel ansambli U-2 laulja-kitarristi Bono sünnipäevakontert. Üritust soojendab DJ Zwillig ning peaesinejateks on ansamblid The Bluesyard ja Sequence

Extractive and spectrophotometric determination of U (VI) using 5-(3-phenolyl azo)-2-hydroxy-4-ethoxy propiophenone oxime (PHEPO)

International Nuclear Information System (INIS)

Subrahmanyam, P.; Krishnapriya, B.; Rekha, D.; Reddy Prasad, P.; Chiranjeevi, P.

2007-01-01

A simple spectrophotometric method for the determination of U (VI) using 5-(3-phenolyl azo)-2-hydroxy-4-ethoxy propiophenone oxime (PHEPO) is developed. The reagent PHEPO was synthesized and used for extraction of uranium. At pH 8.5-10.0 uranium forms a purple colored complex with PHEPO which was then quantitatively extracted in chloroform showing maximum absorbance at wavelength of 380nm. The proposed method obeys Beer's law in the range of 1.2-19.0ppm. molar absorptivity and Sandelson's sensitivity of extracted species were calculated to be 1.750 x 104 lmol-1 cm-1 and 8.5 x 10-5 mg cm-2 respectively. The method was applied for the determination of uranium in synthetic and plant samples. It was found that the newly developed method is competent to those of standard methods. (author)

Absence of U(1) anomalous superamplitudes in N≥5 supergravities

Energy Technology Data Exchange (ETDEWEB)

Freedman, Daniel Z. [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,Stanford, CA 94305 (United States); Center for Theoretical Physics and Department of Mathematics,Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Kallosh, Renata; Murli, Divyanshu [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,Stanford, CA 94305 (United States); Proeyen, Antoine Van [KU Leuven, Institute for Theoretical Physics,Celestijnenlaan 200D, B-3001, Leuven (Belgium); Yamada, Yusuke [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,Stanford, CA 94305 (United States)

2017-05-12

We list all potential candidates for U(1) anomalous non-local 1-loop 4-point amplitudes and higher loop UV divergences in N≥5 supergravities. The relevant chiral superinvariants are constructed from linearized chiral superfields and define the corresponding superamplitudes. The anomalous amplitudes, of the kind present in N=4, are shown to be absent in N≥5. In N=6 supergravity the result is deduced from the double-copy (N=4){sub YM}×(N=2){sub YM} model, whereas in N=5,8 the result on absence of anomalous amplitudes is derived in supergravities as well as in the (N=4){sub YM}×(N−4){sub YM} double-copy models.

Analysis of 235U enrichment by chemical exchange in U(IV) - U(VI) system on anionite

International Nuclear Information System (INIS)

Raica, Paula; Axente, Damian

2007-01-01

Full text: A theoretical study about the 235 U enrichment by chemical exchange method in U(IV)-U(VI) system on anion-exchange resins is presented. The 235 U isotope concentration profiles along the band were numerically calculated using an accurate mathematical model and simulations were carried out for the situation of product and waste withdrawal and feed supply. By means of numerical simulation, an estimation of the migration time, necessary for a desired enrichment degree, was obtained. The required migration distance, the production of uranium 3 at.% 235 U per year and the plant configuration are calculated for different operating conditions. An analysis of the process scale for various experimental conditions is also presented. (authors)

Synthesis of (+)-(3R)-3-(4-fluorophenylsulfonamido)-1,2,3,4-tetrahydro-9-[5,6,7,8,12,13-u-{sup 14}C]carbazoleppropanoic acid, [{sup 14}C]BAY u 3405

Energy Technology Data Exchange (ETDEWEB)

Radtke, M; Boberg, M; Pleiss, U [Inst. of Pharmacokinetics, Bayer AG, Wuppertal (Germany); Rosentreter, U [Pharma Production, Bayer AG. Wuppertal (Germany)

1994-12-01

The title compound [{sup 14}C]BAY u 3405 (1) was synthesized as part of 8-step sequence. Starting from [U-{sup 14}C]aniline hydrogensulfate the final product 1 was obtained with a specific activity of 741 MBq/mmol (20 mCi/mmol) and a radiochemical purity of > 98 % in an overall yield of 6 and 10 % depending on the method. (author).

Effect of lattice distortion on uranium magnetic moments in U4Ru7Ge6 studied by polarized neutron diffraction

Science.gov (United States)

Vališka, Michal; Klicpera, Milan; Doležal, Petr; Fabelo, Oscar; Stunault, Anne; Diviš, Martin; Sechovský, Vladimír

2018-03-01

In a cubic ferromagnet, small spontaneous lattice distortions are expected below the Curie temperature, but the phenomenon is usually neglected. This study focuses on such an effect in the U4Ru7Ge6 compound. Based on DFT calculations, we propose a lattice distortion from the cubic I m -3 m space group to a lower, rhombohedral, symmetry described by the R -3 m space group. The strong spin-orbit coupling of the uranium ions plays an essential role in lowering the symmetry, giving rise to two different U sites (U1 and U2). Using polarized neutron diffraction in applied magnetic fields of 1 and 9 T in the ordered state (1.9 K ) and in the paramagnetic state (20 K ), we bring convincing experimental evidence of this splitting of the U sites, with different magnetic moments. The data have been analyzed both by maximum entropy calculations and by a direct fit in the dipolar approximation. In the ordered phase, the μL/μS ratio of the orbital and spin moments on the U2 site is remarkably lower than for the free U3 + or U4 + ion, which points to a strong hybridization of the U 5 f wave functions with the 4 d wave functions of the surrounding Ru. On the U1 site, the μL/μS ratio exhibits an unexpectedly low value: the orbital moment is almost quenched, like in metallic α -uranium. As a further evidence of the 5 f -4 d hybridization in the U4Ru7Ge6 system, we observe the absence of a magnetic moment on the Ru1 site, but a rather large induced moment on the Ru2 site, which is in closer coordination with both U positions. Very similar results are obtained at 20 K in the ferromagnetic regime induced by the magnetic field of 9 T . This shows that applying a strong magnetic field above the Curie temperature also leads to the splitting of the uranium sites, which further demonstrates the intimate coupling of the magnetic ordering and structural distortion. We propose that the difference between the magnetic moment on the U1 and U2 sites results from the strong spin

Study of new U(VI) and Pu(VI) coprecipitation methods for the preparation of (U,Pu)O2

International Nuclear Information System (INIS)

Sanoit, J. de.

1990-01-01

Two U(VI) and Pu(VI) coprecipitation methods have been studied, for the definition of new processes to prepare (U,Pu)O 2 mixed oxides suitable for making MoX fuels or fast breeder reactor fuels. The first system is based on the coprecipitation of a new U(VI), Pu(VI) compound; ammonium uranoplutonate, where as a second system is related to the precipitation of uranyl plutonyl monocarbonate. Experimental conditions to optimize the precipitation and the filtration steps of these two systems have been determined. After calcination under reducing conditions, the mixed oxides obtained are characterized according to different techniques: granulometry, thermogravimetry, solubility in boiling HNO 3 solutions. The properties of such oxides are excellent. The possible processes for preparing (U, Pu)O 2 using these new routes are compared with those actually exploited [fr

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

Science.gov (United States)

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

Anomalous isotope effects in the U(IV)-U(VI) exchange system

International Nuclear Information System (INIS)

Fujii, Yasuhiko; Nomura, Masao; Okamoto, Makoto; Onitsuka, Hatsuki; Nakanishi, Takashi.

1992-01-01

In previous papers, the enrichment of 236 U in the U(IV) - U(VI) chemical exchange system was found to be significantly smaller than the value estimated by the normal mass dependence enrichment of 235 U. Further experiments have been carried out in the present work to confirm the strange phenomenon of the isotopic anomaly in uranium enrichment. The results have indicated that the separation coefficient of 236 U is the same value as one previously reported. To confirm the anomaly of uranium isotope separation, α-ray spectrometry was implemented to check the enrichment behavior of 234 U. Although no theoretical explanation is given for the isotopic anomaly, this is favorable phenomenon for the re-enrichment of recycled uranium which contains isotopes 232 U and 236 U. (author)

G U Kulkarni

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science. G U Kulkarni. Articles written in Bulletin of Materials Science. Volume 24 Issue 5 October 2001 pp 515-521 Magnetic Materials. Submicron particles of Co, Ni and Co–Ni alloys · P Saravanan T A Jose P John Thomas G U Kulkarni · More Details Abstract Fulltext PDF. Magnetic ...

Effect of anthropogenic organic complexants on the solubility of Ni, Th, U(IV) and U(VI)

Energy Technology Data Exchange (ETDEWEB)

Felipe-Sotelo, M., E-mail: m.felipe-sotelo@lboro.ac.uk [Department of Chemistry, Loughborough University, LE11 3TU Loughborough, Leicestershire (United Kingdom); Edgar, M. [Department of Chemistry, Loughborough University, LE11 3TU Loughborough, Leicestershire (United Kingdom); Beattie, T. [MCM Consulting. Täfernstrasse 11, CH 5405 Baden-Dättwil (Switzerland); Warwick, P. [Enviras Ltd., LE11 3TU Loughborough, Leicestershire (United Kingdom); Evans, N.D.M.; Read, D. [Department of Chemistry, Loughborough University, LE11 3TU Loughborough, Leicestershire (United Kingdom)

2015-12-30

Highlights: • Citrate increases the solubility of Ni, Th and U between 3 and 4 orders of magnitude. • Theophrastite is the solubility controlling phase of Ni in 95%-saturated Ca(OH){sub 2}. • U(VI) and Ni may form Metal-citrate-OH complexes stabilised by the presence of Ca{sup 2+}. - Abstract: The influence of anthropogenic organic complexants (citrate, EDTA and DTPA from 0.005 to 0.1 M) on the solubility of nickel(II), thorium(IV) and uranium (U(IV) and U(VI)) has been studied. Experiments were carried out in 95%-saturated Ca(OH){sub 2} solutions, representing the high pH conditions anticipated in the near field of a cementitious intermediate level radioactive waste repository. Results showed that Ni(II) solubility increased by 2–4 orders of magnitude in the presence of EDTA and DTPA and from 3 to 4 orders of magnitude in the case of citrate. Citrate had the greatest effect on the solubility of Th(IV) and U(IV)/(VI). XRD and SEM analyses indicate that the precipitates are largely amorphous; only in the case of Ni(II), is there some evidence of incipient crystallinity, in the form of Ni(OH){sub 2} (theophrastite). A study of the effect of calcium suggests that U(VI) and Ni(II) may form metal-citrate-OH complexes stabilised by Ca{sup 2+}. Thermodynamic modelling underestimates the concentrations in solution in the presence of the ligands for all the elements considered here. Further investigation of the behaviour of organic ligands under hyperalkaline conditions is important because of the use of the thermodynamic constants in preparing the safety case for the geological disposal of radioactive wastes.

Measurements at the RA Reactor related to the VISA-2 project - Part 3, calculation of VISA-2 samples influence on the reactor reactivity, on the depression of thermal neutron flux in VK-5 channel and VISA-2 samples; Fizicka merenja na reaktoru RA u vezi projekta VISA-2 - III deo, Proracun uticaja uzoraka VISA-2 na reaktivnost reaktora, na depresiju fluksa termalnih neuntrona u kanalu VK-5 i u uzorcima VISA-2