[en] Spectroscopy of the starlike optical counterpart to IRAS 21282+5050, a source with the hydrocarbon infrared emission band spectrum, shows an 07(f)-(WC11) planetary nebula nucleus suffering an extinction of 5.7 mag. Emission line widths in the WC spectrum are only approx. 100 km/s, indicating a very slow stellar wind. Optical diffuse interstellar bands (DIBs) are prominent. Five DIBs are strongly enhanced, namely lamda lamda 5797, 6196, 6203, 6283, and 6613. The presence of circumstellar hydrocarbon molecules may explain both the infrared emission bands and the enhanced DIBs

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No abstract available

[en] Eighteen plutonium oxide samples originating from the Plutonium Finishing Plant (PFP) on the Hanford Site were analyzed to provide additional data on the suitability of PFP thermally stabilized plutonium oxides and Rocky Flats oxides as alternate feedstock to the Mixed Oxide Fuel Fabrication Facility (MFFF). Radiochemical and chemical analyses were performed on fusions, acid leaches, and water leaches of these 18 samples. The results from these destructive analyses were compared with nondestructive analyses (NDA) performed at PFP and the acceptance criteria for the alternate feedstock. The plutonium oxide materials considered as alternate feedstock at Hanford originated from several different sources including Rocky Flats oxide, scrap from the Remote Mechanical C-Line (RMC) and the Plutonium Reclamation Facility (PRF), and materials from other plutonium conversion processes at Hanford. These materials were received at PFP as metals, oxides, and solutions. All of the material considered as alternate feedstock was converted to PuO2 and thermally stabilized by heating the PuO2 powder at 950 C in an oxidizing environment. The two samples from solutions were converted to PuO2 by precipitation with Mg(OH)2. The 18 plutonium oxide samples were grouped into four categories based on their origin. The Rocky Flats oxide was divided into two categories, low- and high-chloride Rocky Flats oxides. The other two categories were PRF/RMC scrap oxides, which included scrap from both process lines and oxides produced from solutions. The two solution samples came from samples that were being tested at Pacific Northwest National Laboratory because all of the plutonium oxide from solutions at PFP had already been processed and placed in 3013 containers. These samples originated at the PFP and are from plutonium nitrate product and double-pass filtrate solutions after they had been thermally stabilized. The other 16 samples originated from thermal stabilization batches before canning at PFP. Samples varied in appearance depending on the original source of material. Rocky Flats items were mostly dark olive green with clumps that crushed easily with a mortar and pestle. PRF/RMC items showed more variability. These items were mostly rust colored. One sample contained white particles that were difficult to crush, and another sample was a dark grey with a mixture of fines and large, hard fragments. The appearance and feel of the fragments indicated they might be an alloy. The color of the solution samples was indicative of the impurities in the sample. The double-pass filtrate solution was a brown color indicative of the iron impurities in the sample. The other solution sample was light gray in color. Radiochemical analyses, including thermal ionization mass spectrometry (TIMS), alpha and gamma energy analysis (AEA and GEA), and kinetic phosphorescence analysis (KPA), indicate that these materials are all weapons-grade plutonium with consistent plutonium isotopics. A small amount of uranium (<0.14 wt%) is also present in these samples. The isotopic composition of the uranium varied widely but was consistent among each category of material. The primary water-soluble anions in these samples were Cl-, NO3-, SO42-, and PO43-. The only major anion observed in the Rocky Flats materials was Cl-, but the PRF/RMC samples had significant quantities of all of the primary anions observed. Prompt gamma measurements provide a representative analysis of the Cl- concentration in the bulk material. The primary anions observed in the solution samples were NO3-, and PO43-. The concentration of these anions did not exceed the mixed oxide (MOX) specification limits. Cations that exceeded the MOX specification limits included Cr, Fe, Ni, Al, Cu, and Si. All of the samples exceeded at least the 75% specification limit in one element

[en] Approach to Connect Global Objectives and Local Actions: (1) Articulate global objectives into a hierarchy of subsystem requirements and local attributes and measures; (2) Establish a baseline system and viable alternatives through the interactions and relationships (e.g., networks) of local system elements and their options; (3) Evaluate performance of system alternatives and develop improved nuclear material management strategies and technologies; and (4) The need to address greatest concerns first (prioritized or graded approach) and to make tradeoffs among implementation options and competing objectives entails a risk-based approach. IGNMM could provide a systematic understanding of global nuclear materials management and evolutionarily improve and integrate the management through an active architecture, using for example, situation awareness, system models, methods, technologies, and international cooperation. Different tools would be used within the overall framework to address individual issues on the desired geographic scale that could be easily linked to broader analyses. Life-cycle system analyses would allow for evaluating material path alternatives on an integrated global scale. Disconnects, overlaps, technical options, and alternatives for optimizing nuclear materials processes could be evaluated in an integrated manner

[en] We have initiated a systematic study of sediment-hydrate interaction under subsurface-mimic conditions to initially focus on marine hydrates. A major obstacle to studying natural hydrate systems has been the absence of a sophisticated mimic apparatus in which the hydrate formation phenomenon can be reproduced with precision. We have designed and constructed a bench-top unit, namely flexible integrated study of hydrates (FISH), for this purpose. The unit is fully instrumented to precisely record temperatures, pressures and changes in gas volume during absorption/evolution. The Labview software allows rapid and continuous data collection during the hydrate formation/dissociation cycle. In our integrated approach, several host sediments collected from Blake Ridge, a well-researched hydrate site, were characterized using the computed microtomography technique at Beamline X-26A of the National Synchrotron Light Source at Brookhaven National Laboratory. The characterized depleted sediments were then used to study the hydrate formation/decomposition kinetics under various pressures in the FISH unit. We report two hydrate formation methods: one under continuous methane gas-flow conditions (dynamic mode) and the other in which hydrates are formed from the dissolved gas phase by diffusion (static mode). Also reported is a depressurization method, namely the step-down pressure method, to yield gas evolution data. Data from such runs with host sediment from the deepest site (667 metres) is presented. During hydrate formation, the data reveals a temperature signature that is consistent with an exothermic hydrate formation event. In the decomposition cycle, data at various pressures was analysed to yield curves with similar slopes, suggesting a zero-order dependence. The capabilities of the FISH unit and the implications of these runs in establishing a database of sediment-hydrate kinetics and pore saturation are discussed.

[en] A radiobiological intercomparison study was performed on the neutron therapy facility at the National Accelerator Centre (NAC) in conjunction with personnel from the Universite Catholique de Louvain, Belgium. The relative biological effectiveness of the neutron beam with respect to ⁶⁰Co was determined. The biological criterion was the regeneration of mice intestinal crypts, 3.5 days after total body irradiation with a single dose. A physical dosimetry intercomparison was undertaken at the same time. Both biological and dosimetric intercomparison are an essential prerequisite for the comparison of clinical data. The dosimetry measurements for the radiobiological experiments are presented here

[en] To determine the Hilbert space and inner product for a quantum theory defined by a non-Hermitian PT-symmetric Hamiltonian H, it is necessary to construct a new time-independent observable operator called C. It has recently been shown that for the cubic PT-symmetric Hamiltonian H=p²+x²+iεx³ one can obtain C as a perturbation expansion in powers of ε. This Letter considers the more difficult case of noncubic Hamiltonians of the form H=p²+x²(ix)^δ (δ≥0). For these Hamiltonians it is shown how to calculate C by using nonperturbative semiclassical methods

[en] Hydrogeology no longer only relies on understanding of phreatic systems. Highly heterogeneous and anisotropic conditions in soil and rock comprising intergranular, fractured and karstic porosity affect groundwater vulnerability, recharge rates, drainage and dewatering practices, soil corrosivity, natural attenuation of contaminants, and integrity of infrastructure, to name a few examples. Movement of water at partial and highly variable saturation is very complex, depending on very small-scale variations in ground conditions as well as very subtle changes in moisture content. In contributing to this, a number of research projects were conducted, focused around physical experiments in the laboratory or mimicked in the field, and subjected to differing conditions pertaining to gravitational acceleration to scale the vertical dimension. Studies contribute to flow mechanisms and flow regimes of variably saturated soils and rocks, as well as the interface between, and link available theoretical understanding and empirical approaches to physical experiments and field verification experiments. Where possible, hydraulic parameters are estimated to improve the quantification of said parameters at discreet scale rather than assuming single values for bulk systems. Obvious limitations and assumptions are understood to the extent that updated flow scenarios are proposed to contribute to variably saturated flow systems. Behaviour is inferred for fractures of changing orientation, changes in medium from soil to rock, and for alternation between wetting and drying of different media. Selected experiments will be presented to highlight novel findings and the way forward.

No abstract available