offers diverse, complex, and valuable building blocks and products. Second, Consortium researchers developed technologies to enable process intensification, which can reduce equipment needs, energy consumption, and waste generation, thereby cutting bioprocessing capital costs and rendering processes more efficient. Third, the Consortium sought to recover carbon from dilute aqueous streams that are common to bioprocessing; recovering dilute carbon can improve process efficiency and economics. Finally, Consortium researchers designed and developed new materials and catalysts to reduce targeted foulants and poisons in bioprocessing streams that can limit the lifetime of downstream catalysts or fermenting microorganisms. Table 1 lists the technologies that were examined and places them in the context of the Consortium’s capabilities, types of bioprocesses, and critical challenges in bioprocessing separations. Overall, across these projects, we have developed separations technologies for 10 bioprocesses, addressed 9 target compounds in bioprocessing, developed 10 materials, and evaluated 4 processes for cost and sustainability.

diffusivity is larger than the self-diffusion coefficient by ahout a factor of seven. This may result from an increase in diffusivity on annealing, or it may be due to the fact that the U-- C system is far from an ideal solution. (auth)

The accurate interpretation of uranium metal 230 Th/ 234 U and 231 Pa/ 235 U radiochronometry model ages requires an understanding of how uranium parent nuclides and decay progeny ( 230 Th and 231 Pa) behave during uranium metal casting. In order to directly measure the spatial distribution of 230 Th and 231 Pa in uranium metal before and after vacuum induction melting (VIM), Los Alamos National Laboratory identified uranium metal feedstock, characterized the metal feedstock, conducted a controlled casting experiment of an approximately 120 kg uranium metal rod, and characterized the cast metal. This study presents radiochronometry results and quantified 230 Th and 231 Pa VIM separation factors from bulk uranium.

of the possibility of compliance with standards which would conform to the US Envionmental Protection Agency's (EPA) Interpretative Ruling of December, 1976. Only under a fortuitous set of regulations and events is it likely that compliance will be demonstrated. If the San Francisco Bay Area or if the vicinity of a proposed site is deemed not a non-attainment area for particulates, or if it is and trade-offs can be obtained through very diligent efforts; if ambient CO standards are being met through futher reduction of automotive pollution; and finally if NO/sub x/ offsets can be obtained through retrofitting existing PG and E facilities - a difficult task according to all parties; if all of these conditions prevail, then PG and E might demonstrate compliance. The Committee notes that it is the Staff's opinion that some of these tasks will be extremely difficult if not impossible to accomplish. The Committee recommends that the Commission approve the NOI and allow PG and E to make the decision whether or not to pursue an AFC. But for its own planning purposes, the Commission would be unwise to count on this poject.

The addition of boron to steel alloys results in an increase in both hardenability and casting defects. The casting difficulties are predicted to stem from a metatectic reaction, delta + gamma -> L + gamma, where a fully solidified material begins to locally remelt as the temperature decreases. Another possible source of casting defects is a boride-rich phase that is predicted to remain liquid at low temperatures. To experimentally determine which reaction is the likely source of the casting defects, the predicted reactions and the effect of solute elements on those reactions are investigated. Levitation zone melting is used to control segregation in a ternary Fe-C-B alloy and a commercial 22MnB5 alloy. Carbon segregation and a peritectic reaction result in a peritectic jump during directional solidification where the first directionally solidified (DS) zone undergoes delta-bcc solidification followed by a peritectic jump to steady state planar solidification of gamma-fcc in the second DS zone. The presence of other solute elements in the zone melted 22MnB5 alloy lead to a breakdown in the planar solidification front before steady state solidification could be achieved in the second DS zone. With a cellular solid/liquid interface, boron-rich intercellular liquid formed low melting iron boro-carbide particles. The controlled solidification conditions in a levitation zone melter were unable to prevent similar to 0.003 wt% boron from segregating to high enough levels to form boride particles. Therefore, it is likely that during commercial casting, the formation of the low melting boride phase from interdendritic segregation is a key source of the casting issues.

Microwave-cast material dating from the latest prototype development period and subsequent TRL 7 advancement testing was sent to LANL for additional characterization. The initial characterization described here is considered a supplement to and verification of that performed by Y-12 during the Technology Readiness Assessment process. The carbon chemistry results from Y-12 and LANL regarding early prototype microwave cast test object (CTO) and cylinder castings match within expectations. Only one fully intact as-cast CTO was available for examination in which carbon chemistry does not appear to vary spatially, at least at relatively low carbon levels (hypoeutectic). The large as-cast grain size leads to relatively poor grain size statistics and similar difficulties were encountered during the TRA. Small, isolated gas pores were observed in four of the five metallographic samples in prototype CTO casting PT-01. Finally, the next phase of characterization work, which focuses on corrosion behavior, has started and is described briefly.

An effort to commence conversion of the High Flux Isotope Reactor (HFIR) to a low enriched uranium (LEU) based fuel has been proposed. While recent experience from LEU-10wt%Mo (U-10Mo) monolithic metal fuel production may be leveraged considerably, the significant differences between research fuels requires some degree of strategy reassessment. In that spirit, initial casting trials have been performed at LANL over the last two years in order develop a high quality starting metal ingot.

Despite the well-known advantages of the titanium-based implant systems, they still lack an optimal balance between biofunctionality and mechanical strength, especially regarding the modulation of cellular response and a desired implant osseointegration. In this work, we fabricated a nanocomposite based on porous commercially pure grade 4 titanium (c.p. Ti) reinforced with carbon nanotubes (CNT) at 5% and 10% w/w, with the aim of obtaining a nanocomposite with lower stiffness compared to traditional titanium-based implants and with the mechanical strength and bioactivity owed by the CNT. Results obtained by scanning electron microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy characterization showed that the CNT dispersed and incorporated into the porous c.p. Ti matrix. Interestingly, CNT were associated with a higher twining within neighbor Ti grains, which was indeed consistent with an increased in nano-hardness. Biological evaluation by MTT and Comet assay revealed that the nanocomposites did not induce genotoxicity and cytotoxicity on two different cells lines despite the presence of nickel at the surface. Accordingly, a purification step would be required before these CNT can be used for biomedical applications. Our results indicate that incorporation of CNT into porous c.p. Ti is a promising avenue to achieve an adequate balance between biofunctionality and mechanical strength in Ti-based scaffolds for tissue replacement. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 719-731, 2019.

The use of advanced high strength steels, such as boron containing steels, in the automotive industry is enabling lighter weight vehicles leading to increased fuel economies. However, boron containing steels are difficult to commercially produce. Thermodynamic studies of the Fe-B system predict a metatectic reaction, delta -> L + gamma, to occur on the iron-rich side of the diagram. This would result in solid material remelting as the temperature is decreased, which could be the source of the casting defects. To experimentally investigate the predicted metatectic reaction, levitation zone melting is used to control the boron segregation in two simple Fe-B binary alloys, and confocal scanning laser microscopy allows for in-situ observation of local microstructural changes as temperature is varied. Both experimental methods show evidence of a metatectic reaction providing a good comparison to predicted phase diagrams. Based on the experimental results, the metatectic reaction occurs over a broader range of compositions than predicted with C-s = 0.0025 wt% B, C-L = 2.0 wt% B, and C-R ranging from approximately 0.03 to 0.06 wt% B. (C) 2017 Elsevier B.V. All rights reserved.

This work examines the effect of boron and lithium conditioned ATJ graphite surface bombarded by low-energy deuterium atoms on the deuterium retention and chemical sputtering. We use atomistic simulations and compare them with experimental in situ studies with x-ray photoelectron spectroscopy (XPS), to understand the effects of deuterium irradiation on the chemistry in lithiated, boronized and oxidized amorphous carbon surfaces. Our results are validated qualitatively by comparison with experiments and with quantum classical molecular dynamic simulations. We explain the important role of oxygen in D retention for lithiated surfaces and the suppression of oxygen role by boron in boronized surfaces. The calculated increase of the oxygen role in deuterium uptake after D accumulation in B-C-O surface configuration is discussed. The sputtering yield per low energy D impact is significantly smaller in boronized than in lithiated surfaces. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

Laboratory experiments have been used to investigate the fundamental interactions responsible for deuterium retention in lithiated graphite. Oxygen was found to be present and play a key role in experiments that simulated NSTX lithium conditioning, where the atomic surface concentration can increase to >40% when deuterium retention chemistry is observed. Quantum-classical molecular dynamic simulations elucidated this oxygen-deuterium effect and showed that oxygen retains significantly more deuterium than lithium in a simulated matrix with 20% lithium, 20% oxygen, and 60% carbon. Simulations further show that deuterium retention is even higher when lithium is removed from the matrix. Experiments artificially increased the oxygen content in graphite to ∼16% and then bombarded with deuterium. X-ray photoelectron spectroscopy showed depletion of the oxygen and no enhanced deuterium retention, thus demonstrating that lithium is essential in retaining the oxygen that thereby retains deuterium.

Lithium wall conditioning in NSTX has resulted in reduced divertor recycling, improved energy confinement, and reduced frequency of edge-localized modes (ELMs), up to the point of complete ELM suppression. NSTX tiles were removed from the vessel following the 2008 campaign and subsequently analyzed using X-ray photoelectron spectroscopy as well as nuclear reaction ion beam analysis. In this paper we relate surface chemistry to deuterium retention/recycling, develop methods for cleaning of passivated NSTX tiles, and explore a method to effectively extract bound deuterium from lithiated graphite. Li–O–D and Li–C–D complexes characteristic of deuterium retention that form during NSTX operations are revealed by sputter cleaning and heating. Heating to ∼850 °C desorbed all deuterium complexes observed in the O 1s and C 1s photoelectron energy ranges. Tile locations within approximately ±2.5 cm of the lower vertical/horizontal divertor corner appear to have unused LiO bonds that are not saturated with deuterium, whereas locations immediately outboard of this region indicate high deuterium recycling. X-ray photo electron spectra of a specific NSTX tile with wide ranging lithium coverage indicate that a minimum lithium dose, 100–500 nm equivalent thickness, is required for effective deuterium retention. This threshold is suspected to be highly sensitive to surface morphology. The present analysis may explain why plasma discharges in NSTX continue to benefit from lithium coating thickness beyond the divertor deuterium ion implantation depth, which is nominally <10 nm.

We investigate the mechanism of deuterium retention by lithiated graphite and its relationship to the oxygen concentration through surface sensitive experiments and atomistic simulations. Deposition of lithium on graphite yielded 5%–8% oxygen surface concentration and when subsequently irradiated with D ions at energies between 500 and 1000 eV/amu and fluences over 1016 cm−2 the oxygen concentration rose to between 25% and 40%. These enhanced oxygen levels were reached in a few seconds compared to about 300 h when the lithiated graphite was allowed to adsorb oxygen from the ambient environment under equilibrium conditions. Irradiating graphite without lithium deposition, however, resulted in complete removal of oxygen to levels below the detection limit of XPS (e.g., <1%). These findings confirm the predictions of atomistic simulations, which had concluded that oxygen was the primary component for the enhanced hydrogen retention chemistry on the lithiated graphite surface.