Update on Fresh Fuel Characterization of U-Mo Alloys

The need to provide more accurate property information on U-Mo fuel alloys to operators, modellers, researchers, fabricators, and government increases as success of the GTRI Reactor Convert program continues. This presentation provides an update on fresh fuel characterization activities that have occurred at the INL since the RERTR 2008 conference in Washington, D.C. The update is particularly focused on properties recently obtained and on the development progress of new measurement techniques. Furthermore, areas where useful and necessary information is still lacking is discussed. The update deals with mechanical, physical, and microstructural properties for both integrated and separate effects. Appropriate discussion of fabrication characteristics, impurities, thermodynamic response, and effects on the topic areas are provided, along with a background on the characterization techniques used and developed to obtain the information. Efforts to measure similar characteristics on irradiated fuel plates are discussed

Fresh Fuel Characterization of U-Mo Alloys

The need to provide more accurate property information on U-Mo fuel alloys to reactor operators, modelers, researchers, fabricators, and regulators increases as success of the RERTR program continues. This presentation will provide an overview of fresh fuel U-Mo characterization activities on monolithic fuel occurring at the Idaho National Laboratory. The overview will particularly be focused on properties available through current and previous research, and also on the type of information still needed. The presentation will deal with mechanical, physical, and microstructural properties in terms of both integrated and separate effects. Appropriate discussion in terms of fabrication characteristics, impurities, thermodynamic response, and the effects on the topic areas will be provided, along with a brief background on the characterization techniques being used or being developed to obtain the information. Furthermore, efforts to measure similar characteristics as a function of irradiation conditions and determine end-of-life observations with beginning-of-life behavior will be discussed

Renin, endothelial no synthase and endothelin gene expression in the 2Kidney-1clip goldblatt model of long-term renovascular hypertension

<p>Abstract</p> <p>Objective</p> <p>Numerous reports have shown the influence of renin, nitric oxide (NO) and the endothelin (ET) systems for regulation of blood pressure and renal function. Furthermore, interactions between these peptides have been reported. Aim of our study was to investigate the relative contribution of these compounds in long-term renovascular hypertension/renal ischemia.</p> <p>Methods</p> <p>Hypertension/left-sided renal ischemia was induced using the 2K1C-Goldblatt rat model. Renal renin, ET-1, ET-3 and endothelial NO synthase (eNOS) gene expression was measured by means of RNAse protection assay at different timepoints up to 10 weeks after induction of renal artery stenosis.</p> <p>Results</p> <p>Plasma renin activity and renal renin gene expression in the left kidney were increased in the clipped animals while eNOS expression was unchanged. Furthermore, an increase in ET-1 expression and a decrease of ET-3 expression was detected in early stenosis.</p> <p>Conclusions</p> <p>While renin is obviously involved in regulation of blood pressure and renal function in unilateral renal artery stenosis, ET-1, ET-3 and endothelium derived NO do not appear to play an important role in renal adaptation processes in long-term renal artery stenosis, although ET-1 and ET-3 might be involved in short-term adaptation processes.</p

SHL-101/T SONAR - results of the harbour and sea trials

The safeguard of seaways, naval basis, harbours and sea frontiers from minefields, attackers, gun-running is essential in hazardous nowadays. Particularly modern sea mines sometimes buried and make in stealth technology are very difficult to detect. Therefore the echo-ranging detection systems require state-of-the-art hardware and efficient processing algorithms to protect sea areas. Such up-to-date hydroacoustic equipment was developed by R&D Marine Technology Centre. The SHL-101/T system is the triple frequency, wideband and very high resolution hull-mounted minehunting sonar. It was put into service to Polish Navy minesweeper on April 2007. Sonar underwent factory, harbour and sea acceptance trials. Presently Polish Navy carries out further exploitation and military tests. The results are remarkable and they enable to explore mysteries of the sunken objects in the Gdansk Gulf. The paper presents the results of SHL-101/T sonar harbour and sea trials. Its performances for different detection and classification modes are also depicted. Additionally displays of the found various underwater objects are included and detailed discussed

Thermotransport In Γ(Bcc) U-Zr Alloys: A Phase-Field Model Study

Atomic transport in the presence of a temperature gradient, commonly known as thermotransport or the thermomigration phenomenon, was simulated for U-Zr alloys using a phase-field model derived from irreversible thermodynamics. The free energy of the U-Zr system, a necessary ingredient for the phase-field-model, was directly incorporated from the available thermodynamic database. Kinetic parameters such as atomic mobility and heat of transport terms were obtained from experimental values reported in the literature. The model was applied to a single-phase (bcc-γ phase) alloy and to a diffusion couple consisting of two single-phase (bcc-γ phase) alloys of different compositions, both subjected to a constant temperature gradient. Constituent redistribution in the absence and presence of a compositional gradient was examined. An enrichment of Zr with a corresponding depletion of U was observed at the hot end of the initially homogeneous single-phase alloy. A similar atomic transport behavior was observed in the diffusion couple, where the magnitude and direction of the final composition gradient was dictated by the combined influence of atomic mobility and heat of transport terms. © 2010 Elsevier B.V. All rights reserved

electronic reprint Structure Reports Online 1,3-Di-n-butylthiourea

This open-access article is distributed under the terms of the Creative Commons Attribution Licence http://creativecommons.org/licenses/by/2.0/uk/legalcode, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited. Acta Crystallographica Section E: Structure Reports Online is the IUCr&apos;s highly popular open-access structural journal. It provides a simple and easily accessible publication mechanism for the growing number of inorganic, metal-organic and organic crystal structure determinations. The electronic submission, validation, refereeing and publication facilities of the journal ensure very rapid and high-quality publication, whilst key indicators and validation reports provide measures of structural reliability. The journal publishes over 4000 structures per year. The average publication time is less than one month

Impurity migration and effects on vacancy formation enthalpy in polycrystalline depleted uranium

We have used Doppler-broadening of the positron-electron annihilation radiation technique and VASP calculations to verify the previously reported vacancy formation enthalpy Hvf in polycrystalline depleted uranium. Experimentally we have confirmed a Hvf of (1.6 ± 0.2) eV. VASP calculations using GGA and LDA approximations gave vacancy formation enthalpies values of 1.98 eV and 2.22 eV respectively. We found residual oxygen in the sample diminished these values by 50% or more. Our new experimental and theoretical data supports the notion that oxygen impurities in the sample are responsible for lower values of vacancy formation enthalpies. Measured and calculated vacancy formation enthalpies, as well as the obtained oxygen migration enthalpy of (0.6 ± 0.1) eV, are compared and discussed with values reported in the literature.Fil: Lund, K. R.. Washington State University; Estados UnidosFil: Lynn, K. G.. Washington State University; Estados UnidosFil: Weber, M. H.. Washington State University; Estados UnidosFil: Macchi, Carlos Eugenio. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Somoza, Alberto Horacio. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Juan, Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; ArgentinaFil: Okuniewski, M. A.. Idaho National Laboratory; Estados Unido

Mechanisms of augmented vasoconstriction induced by 5-hydroxytryptamine in aortic rings from spontaneously hypertensive rats

Background and purpose: To test whether development of enhanced vasoconstriction to 5-hydroxytryptamine (5-HT; serotonin) in SHR was temporally related to hypertension, elevated vascular superoxide (O2) levels, decreased NO bioavailability, or increased contractile effects of cyclooxygenase or rho-kinase and/or PKC. Experimental approach: We examined systolic blood pressure (SBP), vascular O2, and 5-HT-induced contractile responses of aortic segments from 4- and 8-week-old WKY and SHR. Key results: SBP was 35% higher in SHR than WKY at 4 weeks and 60% higher at 8 weeks. Contractile responses to 5-HT were similar in WKY and SHR at 4 weeks, but were markedly augmented in SHR at 8 weeks. The NO synthase inhibitor, L-NAME, enhanced contractile responses to 5-HT markedly in both strains at 4 weeks and in WKY at 8 weeks, but only very modestly in SHR at 8 weeks. These functional differences were associated with higher O2 levels in SHR versus WKY at 8 weeks, but not at 4 weeks. The rho-kinase inhibitor, Y-27632, and the PKC inhibitor, Ro 31-8220, each only modestly attenuated contractions in WKY and SHR in each age group, and their effects in each strain were more pronounced at 8 weeks. The cyclooxygenase inhibitor, indomethacin, had no effect on contractile responses. Conclusions and implications: Development of augmented vascular contractile responses to 5-HT in SHR is preceded by hypertension. It is associated with increased vascular O2 levels and reduced modulatory effects of NO, and is unlikely to be due to enhanced activity of rho-kinase, PKC or cyclooxygenase