Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 ? 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, ?One good experiment fixes a lot of good theory?. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by …

Mixtures of oxalic acid with nitric acid have been shown to be superior to oxalic acid alone for the dissolution of iron-rich High Level Waste sludge heels. Optimized conditions resulting in minimal oxalate usage and stoichiometric iron dissolution (based on added oxalate ion) have been determined for hematite (a primary sludge iron phase) in oxalic/nitric acid mixtures. The acid mixtures performed better than expected based on the solubility of hematite in the individual acids through a synergistic effect in which the preferred 1:1 Fe:oxalate complex is formed. This allows for the minimization of oxalate additions to the waste stream. Carbon steel corrosion rates were measured in oxalic/nitric acid mixtures to evaluate the impacts of chemical cleaning with these solutions on waste tank integrity. Manageable corrosion rates were observed in the concentration ranges of interest for an acid contact timescale of 1 month. Kinetics tests involving hematite and gibbsite (a primary sludge aluminum phase) have confirmed that {ge}90% solids dissolution occurs within 3 weeks. Based on these results, the chemical cleaning conditions recommended to promote minimal oxalate usage and manageable corrosion include: 0.5 wt. % oxalic acid/0.175 M nitric acid mixture, 50 C, 2-3 week contact time with agitation.

None

None

None

None

The Department of Energy has a large number of nuclear waste tanks. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles, e.g., plutonium containing, could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids and supernatant were charged to the test tank and rotating liquid jets were used to remove most of the solids. Then the volume and shape of the residual solids and the spatial concentration profiles for the surrogate for plutonium were measured. This paper discusses the overall test results, which indicated heavy solids only accumulate during the first few transfer cycles, along with the techniques and equipment designed and employed in the test. Those …

None

None

I present an analysis for fitting cosmological parameters from a Hubble Diagram of a standard candle with unknown intrinsic magnitude dispersion. The dispersion is determined from the data themselves, simultaneously with the cosmological parameters. This contrasts with the strategies used to date. The advantages of the presented analysis are that it is done in a single fit (it is not iterative), it provides a statistically founded and unbiased estimate of the intrinsic dispersion, and its cosmological-parameter uncertainties account for the intrinsic dispersion uncertainty. Applied to Type Ia supernovae, my strategy provides a statistical measure to test for sub-types and assess the significance of any magnitude corrections applied to the calibrated candle. Parameter bias and differences between likelihood distributions produced by the presented and currently-used fitters are negligibly small for existing and projected supernova data sets.

Defining high-level features, detecting them, tracking them and deriving quantities based on them is an integral aspect of modern data analysis and visualization. In combustion simulations, for example, burning regions, which are characterized by high fuel-consumption, are a possible feature of interest. Detecting these regions makes it possible to derive statistics about their size and track them over time. However, features of interest in scientific simulations are extremely varied, making it challenging to develop cross-domain feature definitions. Topology-based techniques offer an extremely flexible means for general feature definitions and have proven useful in a variety of scientific domains. This paper will provide a brief introduction into topological structures like the contour tree and Morse-Smale complex and show how to apply them to define features in different science domains such as combustion. The overall goal is to provide an overview of these powerful techniques and start a discussion how these techniques can aid in the analysis of astrophysical simulations.

A method for simulating Coulomb collisions in plasma simulations is described, in which particle weights are changed, instead of particle velocities.

PBXN-9, an HMX-formulation, is thermally damaged and thermally decomposed in order to determine the morphological changes and decomposition kinetics that occur in the material after mild to moderate heating. The material and its constituents were decomposed using standard thermal analysis techniques (DSC and TGA) and the decomposition kinetics are reported using different kinetic models. Pressed parts and prill were thermally damaged, i.e. heated to temperatures that resulted in material changes but did not result in significant decomposition or explosion, and analyzed. In general, the thermally damaged samples showed a significant increase in porosity and decrease in density and a small amount of weight loss. These PBXN-9 samples appear to sustain more thermal damage than similar HMX-Viton A formulations and the most likely reasons are the decomposition/evaporation of a volatile plasticizer and a polymorphic transition of the HMX from {beta} to {delta} phase.

The scintillation properties of cerium-doped oxyhalides following the general formula REOX (RE=Y, La, Gd, and Lu; X=F, Cl, Br, and I) are reported. These materials were synthesized under dry conditions as microcrystalline powders from conventional solid state reactions. The room temperature X-ray excited emission and scintillation decay curves were measured and analyzed for each material. Additionally, the hygroscopic nature of the oxychlorides and oxybromides was compared to that of their corresponding rare earth halides. The yttrium, lanthanum, and gadolinium oxychlorides, and all of the oxybromides and oxyiodides are found to be activated by Ce{sup 3+}. GdOBr doped with 0.5% Ce{sup 3+} has the highest light output with a relative luminosity of about one-half that of LaBr{sub 3}: Ce{sup 3+}. It displays a single exponential decay of 30 ns.

This article provides an mesophyll and bundle sheath cell type-specific transcriptome data set from the monocot NAD-malic enzyme subtype switchgrass (Panicum virgatum).

Article discussing theories on the evaluation of philosophy and philosophers and the peer review process.

Article describes an experiment in which a hot-electron-enabled route to controlling light with dissipative loss compensation in semiconductor quantum light emitters has been realized for tunable quantum optoelectronic devices via a two-species plasmon system.

Article explores the hypothesis that oxygen diffusion limited the evolution of retinal morphology by reconstructing the evolution of retinal thickness and the various mechanisms for retinal oxygen supply, including capillarization and acid-induced haemoglobin oxygen unloading.

This article presents H-band spectroscopy for a flux-limited sample of 40 z≃ 4.8 active galactic nuclei, selected from the Sloan Digital Sky Survey.

This report talks about Challenges of 4th Generation Light Sources