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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Cryogenic distillation facility for isotopic purification of protium and deuterium

Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Reactor design and integration with product detection to accelerate screening of electrocatalysts for carbon dioxide reduction

Identifying new catalyst materials for complex reactions such as the electrochemical reduction of CO 2 poses substantial instrumentation challenges due to the need to integrate reactor control with electrochemical and analytical instrumentation. Performing accelerated screening to enable exploration of a broad span of catalyst materials poses additional challenges due to the long time scales associated with accumulation of reaction products and the detection of the reaction products with traditional separation-based analytical methods. The catalyst screening techniques that have been reported for combinatorial studies of (photo)electrocatalysts do not meet the needs of CO 2 reduction catalyst research, prompting our development of a new electrochemical cell design and its integration to gas and liquid chromatography instruments. To enable rapid chromatography measurements while maintaining sensitivity to minor products, the electrochemical cell features low electrolyte and head space volumes compared to the catalyst surface area. Additionally, the cell is operated as a batch reactor with electrolyte recirculation to rapidly concentrate reaction products, which serves the present needs for rapidly detecting minor products and has additional implications for enabling product separations in industrial CO 2 electrolysis systems. To maintain near-saturation of CO 2 in aqueous electrolytes, we employ electrolyte nebulization through a CO 2 -rich headspace, achieving similar gas-liquid equilibration as vigorous CO 2 bubbling but without gas flow. The instrument is demonstrated with a series of electrochemical experiments on an Au-Pd combinatorial library, revealing non-monotonic variations in product distribution with respect to catalyst composition. The highly integrated analytical electrochemistry system is engineered to enable automation for rapid catalyst screening as well as deployment for a broad range of electrochemical reactions where product distribution is critical to the assessment of catalyst performance.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Separation and determination of ultratrace rhenium quantities in molybdenum matrix

The production of very pure molybdenum, free of Re even at ultratrace levels, is extremely important in meeting target purity specifications during the production of 99 Mo for medical applications. Here we propose two methods for separating ultratrace levels of Re from a bulk Mo matrix using either solvent extraction or extraction chromatography, combined with inductively coupled plasma quadrupole mass spectrometry (ICP-MS) detection. Re is extracted (D > 70) from solutions in sulfuric acid as a complex with tri-n-butyl phosphate. Scrubbing and washing steps result in total decontamination factors for Mo up to 1,700 for solvent extraction and 3,500 for extraction chromatography. Re is stripped into a 3 M NH 4 OH matrix and analyzed by ICP-MS. Detection (L D ) and quantification (L Q ) limits were optimized by matrix-matching to allow detection of Re in strip solutions at levels of L D = 0.1 ng Re/g-Mo and L Q = 0.3 ng Re/g-Mo in Mo powder samples. By employing these two extraction methods, excellent recoveries of Re from bulk Mo are achieved, and the L Q is improved by a factor of 5 x 10 4 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Selenium Accumulation, Distribution, and Speciation in Spineless Prickly Pear Cactus: A Drought- and Salt-Tolerant, Selenium-Enriched Nutraceutical Fruit Crop for Biofortified Foods

The organ-specific accumulation, spatial distribution, and chemical speciation of selenium (Se) were previously unknown for any species of cactus. We investigated Se in Opuntia ficus-indica using inductively coupled plasma mass spectrometry, microfocused x-ray fluorescence elemental and chemical mapping ({micro}XRF), Se K-edge x-ray absorption near-edge structure (XANES) spectroscopy, and liquid chromatography-mass spectrometry (LC-MS). {micro}XRF showed Se concentrated inside small conic, vestigial leaves (cladode tips), the cladode vasculature, and the seed embryos. Se K-edge XANES demonstrated that approximately 96% of total Se in cladode, fruit juice, fruit pulp, and seed is carbon-Se-carbon (C-Se-C). Micro and bulk XANES analysis showed that cladode tips contained both selenate and C-Se-C forms. Inductively coupled plasma mass spectrometry quantification of Se in high-performance liquid chromatography fractions followed by LC-MS structural identification showed selenocystathionine-to-selenomethionine (SeMet) ratios of 75:25, 71:29, and 32:68, respectively in cladode, fruit, and seed. Enzymatic digestions and subsequent analysis confirmed that Se was mainly present in a 'free' nonproteinaceous form inside cladode and fruit, while in the seed, Se was incorporated into proteins associated with lipids. {micro}XRF chemical mapping illuminated the specific location of Se reduction and assimilation from selenate accumulated in the cladode tips into the two LC-MS-identified C-Se-C forms before they were transported into the cladode mesophyll. We conclude that Opuntia is a secondary Se-accumulating plant whose fruit and cladode contain mostly free selenocystathionine and SeMet, while seeds contain mainly SeMet in protein. When eaten, the organic Se forms in Opuntia fruit, cladode, and seed may improve health, increase Se mineral nutrition, and help prevent multiple human cancers.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2011

Qualification of the First ICS-3000 ION Chromatograph for use at the Defense Waste Processing Facility

The ICS-3000 Ion Chromatography (IC) system installed in 221-S M-13 has been qualified for use. The qualification was a head to head comparison of the ICS-3000 with the currently used DX-500 IC system. The crosscheck work included standards for instrument calibration and calibration verifications and standards for individual anion analysis, where the standards were traceable back to the National Institute of Standards and Technology (NIST). In addition the crosscheck work included the analysis of simulated Sludge Receipt Adjustment Tank (SRAT) Receipt, SRAT Product, and Slurry Mix Evaporator (SME) samples, along with radioactive Sludge Batch 5 material from the SRAT and SME tanks. Based upon the successful qualification of the ICS-3000 in M-13, it is recommended that this task proceed in developing the data to qualify, by a head to head comparison of the two ICS-3000 instruments, a second ICS-3000 to be installed in M-14. The Defense Waste Processing Facility (DWPF) requires the analysis of specific anions at various stages of its processing of high level waste (HLW). The anions of interest to the DWPF are fluoride, formate, chloride, nitrite, nitrate, sulfate, oxalate, and phosphate. The anion analysis is used to evaluate process chemistry including formic acid/nitric acid additions to establish optimum conditions for mercury stripping, reduction-oxidation (REDOX) chemistry for the melter, nitrite destruction, organic acid constituents, etc. The DWPF Laboratory (Lab) has been using Dionex DX-500 ion chromatography (IC) systems since 1998. The vendor informed DWPF in 2006 that the instruments would no longer be supported by service contracts after 2008. DWPF purchased three new ICS-3000 systems in September of 2006. The ICS-3000 instruments are (a) designed to be more stable using an eluent generator to make eluent, (b) require virtually no daily chemical handling by the analysts, (c) require less line breaks in the hood, and (d) generally require less maintenance due to the pump configuration only using water versus the current system where the pump uses various hydroxide concentrations. The ICS-3000 instruments also allow the DWPF to maintain current service contracts, which support routine preventive maintenance and emergency support for larger problems such as component failure. One of the three new systems was set up in the DWPF Lab trailers in January of 2007 to be used for the development of methods and procedures. This system will continue to be used for training, new method development and potential improvements to current methods. The qualification of the other two ICS-3000 instruments is to be a phased effort. This effort is to be supported by the Applied Computational Engineering and Statistical (ACES) group of the Savannah River National Laboratory (SRNL) as authorized by the Technical Task Request (TTR) and as directed by the corresponding Task Technical and Quality Assurance (TT&QA) plan. The installation of the first 'rad' system into the M-13 Lab module required modifications to both the Lab module and to the radiohood. The installation was completed in July 2008. The testing of this system was conducted as directed by the TT&QA plan. The purpose of this technical report is to provide a review of the data generated by these tests that will lead to the recommendation for the qualification of the M-13 ICS-3000 instrument. With the successful qualification of this first ICS-3000, plans will be developed for the installation of the second 'rad' system in the M-14 Lab module later in fiscal year 2009. When the second 'rad' ICS-3000 system is installed, the DX-500 systems will be removed and retired from service.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

Investigation of the hydrolytic and radiolytic degradation of HEH[EHP]

The extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) is a component used in both the Advanced TALSPEAK and ALSEP solvent extraction processes. The most likely compound formed via hydrolytic or radiolytic degradation of HEH[EHP] would be the phosphonic acid 2-ethylhexylphosphonic acid (H2EHP) that is formed by cleavage of the P-O-R bond. Thus far, attempts to detect H2EHP by gas chromatography or mass spectrometry have not been successful. The inability to detect this proposed degradation product in analytical samples is likely due to inadequate analysis techniques, lack of H2EHP production, further decomposition of H2EHP forming products not detectable by the employed analytical techniques, or a combination of all of the above scenarios. In order to address this problem, commercially available alkylphosphonic acids were acquired and used as surrogates for H2EHP in the gas chromatography and mass spectrometry analysis of samples. Once the ability to detect alkylphosphonic acid compounds was confirmed, these analytical techniques were used to confirm the production of H2EHP in samples of HEH[EHP] exposed to nitric acid and nitric acid plus gamma radiation. This report provides a brief summary of results and serves as documentation of the completion the level four milestone M4FT-16IN030102025 “Investigate the hydrolytic and radiolytic degradation of HEH[EHP]”.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Glycolate Analysis in Tank 22: Developing and Testing Analytical Methods for the Savannah River Site Liquid Waste System

Researchers developed and tested a range of techniques to support a low mg/L Limit of Quantitation (LOQ) of glycolate in radioactive Tank 22 waste solution by Ion Chromatography (IC) and by proton NMR. For the IC method, Dionex OnGuard II cartridges were tested as a means of removing alkali earth and transition metals that can interfere during ion chromatography applications especially when analyzing for low-concentration, chelating analytes. Additionally, concentrations of nitrate in the raw Tank 22 sample (5,000 to 10,000 mg/L) were managed by using reasonable levels of sample dilution. The resulting IC performance quality was enhanced by improving the baseline, increasing sensitivity [Limit of Quantitation (LOQ) of 12 mg/L and Limit of Detection (LOD) of 4.0 mg/L], and resolving analytes into well-defined Gaussian peaks when using the Dionex OnGuard II H⁺ cartridges to remove matrix interferences. High concentrations of nitrate limited the performance of the IC method. To achieve an acceptable baseline, samples with high nitrate content require more dilution, resulting in higher detection limits. Tests on samples with higher concentrations of nitrate (Tank 30 and 32 supernate with approximately 150000 mg/L nitrate) suggested that IC detection limits for glycolate in these samples would be > 500 mg/L. Thus, an LOQ of 12 mg/L is not feasible by this IC method on evaporator feed samples. An alternative method of glycolate analysis, using proton nuclear magnetic resonance (H NMR), was developed by the research team. In initial tests, the H NMR technique provided reasonable quantitation of glycolate in Tank 22 conditions by direct observation of the liquid. The H NMR method may provide improved detection limits for solutions with higher nitrate concentrations. We recommend further development of this analysis for high nitrate LWS samples such as evaporator feed and evaporator drop tank content. A method for pretreatment of samples using crystalline silicotitanate (CST) was developed and tested. The objective of the pretreatment was to facilitate analysis of samples with higher levels of radioactivity. The pretreatment did not influence the glycolate concentration in solution, and the pretreatment is projected to reduce Cs 137 activity in a sample by a factor of 16,200. The double strike CST pretreatment was demonstrated and would allow milliliters of higher activity samples to be transferred from the Shielded Cells and handled in a containment unit for glycolate analysis. The various studies validated IC and H NMR methods for glycolate analysis, defined the range of applicability, and demonstrated key supporting analytical protocols. Based on the results, high quality glycolate analysis of Tank 22 is feasible down to approximately 12 mg/L, with the potential for broader applicability of the methods to other conditions in the Savannah River Site Liquid Waste System (LWS).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2026

Dataset_for_Molecular_Motion_Below_the_Glass_Transition_A_Solid-State_NMR_Study_of_Siloxane_Polymer_Dynamics Study

This dataset contains solid-state 1H and 13C NMR relaxometry data, differential scanning calorimetry (DSC) data, and size exclusion chromatography (SEC/GPC) data supporting the study of sub-glass-transition (sub-Tg) molecular dynamics in a composition- and sequence-controlled series of diphenyl-substituted polysiloxanes (PDMS, 14Ph, 33Ph, 50Ph, 67Ph, and 100Ph; 0–100% diphenylsiloxane content by mole).All solid-state NMR data were acquired on a 200 MHz Bruker Avance III HD spectrometer using a static 7 mm HX probe or a 4 mm HX probe under 4 kHz magic-angle spinning. Raw Bruker TopSpin experiment folders are included for: (1) variable-temperature 1H lineshape measurements used to determine linewidth (FWHM) as a function of temperature across the glass transition; (2) 1H T1 (saturation recovery with solid-echo detection), probing nanosecond-scale dynamics near the 1H Larmor frequency; (3) 1H T1rho (direct spin-lock, 62.5 kHz), probing microsecond-scale segmental dynamics; (4) 13C-detected Lee–Goldburg cross-polarization 1H T1rho (LGCPH T1rho) for 33Ph and 50Ph, resolving aromatic and aliphatic proton environments; and (5) 13C T1 relaxation for 33Ph and 50Ph. Differential scanning calorimetry data (TA Instruments DSC 25, −150 to +120 °C, up to +300 °C for 100Ph, 10 °C/min) are included for all six compositions and support the glass-transition temperatures in Table 1 and Figure 1. Size exclusion chromatography data (Agilent 1200 Series, PL-Gel 300 mixed-C column, THF mobile phase, polystyrene calibration standards) are included for the three synthesized copolymers (33Ph, 50Ph, 67Ph) and support the number-average molecular weights in Table 1. Processed data include per-composition relaxation-time summaries (Excel), curve-fitting and Bloembergen-Purcell-Pound (BPP) model analysis notebooks (Jupyter/Python), and Igor Pro (.pxp) master files used to generate the manuscript's figures.

Bloembergen-Purcell-Pound theory↗
DOE OSTI2021

Sensing Techniques for Organochlorides through Intermolecular Interaction with Bicyclic Amidines

Toxic organochloride molecules are widely used in industry for various purposes. With their high volatility, the direct detection of organochlorides in environmental samples is challenging. Here, a new organochloride detection mechanism using 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) is introduced to simplify a sensing method with higher detection sensitivity. Three types of organochloride compounds-trichloroethylene (TCE), dichloromethane (DCM), and dichlorodiphenyltrichloroethane (DDT)—were targeted to understand DCM conjugation chemistry by using nuclear magnetic resonance (NMR) and liquid chromatography with a mass spectrometer (LC-MS). 13C-NMR spectra and LC-MS data indicated that DBN can be labeled on these organochloride compounds by chlorine–nitrogen interaction. Furthermore, to demonstrate the organochloride sensing capability, the labeling yield and limit of detection were determined by a colorimetric assay as well as micellar electrokinetic chromatography (MEKC). The interaction with DBN was most appreciable for TCE, among other organochlorides. TCE was detected at picomolar levels, which is two orders of magnitude lower than the maximum contaminant level set by the United States Environmental Protection Agency. MEKC, in conjunction with this DBN-labeling method, enables us to develop a field-deployable sensing platform for detecting toxic organochlorides with high sensitivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

metabCombiner 2.0: Disparate Multi-Dataset Feature Alignment for LC-MS Metabolomics

Liquid chromatography–high-resolution mass spectrometry (LC-HRMS), as applied to untargeted metabolomics, enables the simultaneous detection of thousands of small molecules, generating complex datasets. Alignment is a crucial step in data processing pipelines, whereby LC-MS features derived from common ions are assembled into a unified matrix amenable to further analysis. Variability in the analytical factors that influence liquid chromatography separations complicates data alignment. This is prominent when aligning data acquired in different laboratories, generated using non-identical instruments, or between batches from large-scale studies. Previously, we developed metabCombiner for aligning disparately acquired LC-MS metabolomics datasets. Here, we report significant upgrades to metabCombiner that enable the stepwise alignment of multiple untargeted LC-MS metabolomics datasets, facilitating inter-laboratory reproducibility studies. To accomplish this, a “primary” feature list is used as a template for matching compounds in “target” feature lists. We demonstrate this workflow by aligning four lipidomics datasets from core laboratories generated using each institution’s in-house LC-MS instrumentation and methods. We also introduce batchCombine, an application of the metabCombiner framework for aligning experiments composed of multiple batches. metabCombiner is available as an R package on Github and Bioconductor, along with a new online version implemented as an R Shiny App.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1998

Kinetic preference for the 3'-5'-linked dimer in the reaction of guanosine 5'-phosphorylmorpholinamide with deoxyguanosine 5'-phosphoryl-2-methylimidazolide as a function of poly(C) concentration

The formation of the internucleotide bond in diguanylate synthesis was studied in aqueous solution at pH 8 and 0.2 M Mg2+ in the presence and absence of polycytidylate, poly(C). The investigation was simplified by using guanosine 5'-phosphorylmorpholinamide, mor-pG, which can act only as a nucleophile, and deoxyguanosine 5'-phosphoryl-2-methylimidazolide, 2-MeImpdG, which can act only as an electrophile. The time-dependent product distribution was monitored by high-performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS). In the absence of poly(C) the reaction between mor-pG and 2-MeImpdG yielded small amounts of the dimer mor-pGpdG with a regioselectivity of 2'-5':3'-5' = 3.5. In the presence of poly(C) dimer yields increased and a reversal in regioselectivity occurred; both effects were in proportion to the concentration of the polymer. The results can be quantitatively explained with the proposition that poly(C), acting as the template, catalyzes the reaction between template-bound monomers by about a factor of 4-5 over the reaction in solution and yields dimers with a regioselectivity of 2'-5':3'-5' approximately 0.33. These findings illustrate the intrinsic preference of guanosine monomers to correctly self-assemble on the appropriate template.

NASA Discipline Exobiology↗
NASA NTRS1996

Phenols in hydrothermal petroleums and sediment bitumen from Guaymas Basin, Gulf of California

The aliphatic, aromatic and polar (NSO) fractions of seabed petroleums and sediment bitumen extracts from the Guaymas Basin hydrothermal system have been analyzed by gas chromatography and gas chromatography-mass spectrometry (free and silylated). The oils were collected from the interiors and exteriors of high temperature hydrothermal vents and represent hydrothermal pyrolyzates that have migrated to the seafloor by hydrothermal fluid circulation. The downcore sediments are representative of both thermally unaltered and thermally altered sediments. The survey has revealed the presence of oxygenated compounds in samples with a high degree of thermal maturity. Phenols are one class of oxygenated compounds found in these samples. A group of methyl-, dimethyl- and trimethyl-isoprenoidyl phenols (C27-C29) is present in all of the seabed NSO fractions, with the methyl- and dimethyl-isoprenoidyl phenols occurring as major components, and a trimethyl-isoprenoidyl phenol as a minor component. A homologous series of n-alkylphenols (C13-C33) has also been found in the seabed petroleums. These phenols are most likely derived from the hydrothermal alteration of sedimentary organic matter. The n-alkylphenols are probably synthesized under hydrothermal conditions, but the isoprenoidyl phenols are probably hydrothermal alteration products of natural product precursors. The suites of phenols do not appear to be useful tracers of high temperature hydrothermal processes.

Non-NASA Center↗
NASA NTRS1986

[3H]Indole-3-acetyl-myo-inositol hydrolysis by extracts of Zea mays L. vegetative tissue

[3H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 37 degrees C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as alpha-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic procedures resulted in only slight purification with large losses of activity. Chromatography over hydroxylapatite allowed separation of two enzymically active fractions, one of which catalyzed the hydrolysis of both indole-3-acetyl-myo-inositol and esterase substrates. With the other enzymic hydrolysis of esterase substrates was readily demonstrated, but no hydrolysis of indole-3-acetyl-myo-inositol was ever detected.

NASA Program Space Biology↗
NASA NTRS1993

Lipid and fatty acid analysis of the Plodia interpunctella granulosis virus (PiGV) envelope

Virus envelope was isolated from Plodia interpunctella granulosis virus, produced in early fourth-instar larvae. Both polar and neutral lipids were analyzed by two-dimensional thin-layer chromatography. Fatty acid composition of various individual neutral and polar lipids was determined by gas-liquid chromatography. The major components of envelope neutral lipid were diacylglycerols. Palmitic acid and stearic acid were the major saturated fatty acids in both polar and neutral lipids. Whereas palmitoleic acid was the major unsaturated fatty acids in neutral lipids, oleic acid was the major unsaturated fatty acid in the polar lipids.

Non-NASA Center↗
DOE OSTI2010

Hydrothermal Liquefaction of Biomass

Hydrothermal liquefaction technology is describes in its relationship to fast pyrolysis of biomass. The scope of work at PNNL is discussed and some intial results are presented. HydroThermal Liquefaction (HTL), called high-pressure liquefaction in earlier years, is an alternative process for conversion of biomass into liquid products. Some experts consider it to be pyrolysis in solvent phase. It is typically performed at about 350 C and 200 atm pressure such that the water carrier for biomass slurry is maintained in a liquid phase, i.e. below super-critical conditions. In some applications catalysts and/or reducing gases have been added to the system with the expectation of producing higher yields of higher quality products. Slurry agents ('carriers') evaluated have included water, various hydrocarbon oils and recycled bio-oil. High-pressure pumping of biomass slurry has been a major limitation in the process development. Process research in this field faded away in the 1990s except for the HydroThermal Upgrading (HTU) effort in the Netherlands, but has new resurgence with other renewable fuels in light of the increased oil prices and climate change concerns. Research restarted at Pacific Northwest National Laboratory (PNNL) in 2007 with a project, 'HydroThermal Liquefaction of Agricultural and Biorefinery Residues' with partners Archer-Daniels-Midland Company and ConocoPhillips. Through bench-scale experimentation in a continuous-flow system this project investigated the bio-oil yield and quality that could be achieved from a range of biomass feedstocks and derivatives. The project was completed earlier this year with the issuance of the final report. HydroThermal Liquefaction research continues within the National Advanced Biofuels Consortium with the effort focused at PNNL. The bench-scale reactor is being used for conversion of lignocellulosic biomass including pine forest residue and corn stover. A complementary project is an international collaboration with Canada to investigate kelp (seaweed) as a biomass feedstock. The collaborative project includes process testing of the kelp in HydroThermal Liquefaction in the bench-scale unit at PNNL. HydroThermal Liquefaction at PNNL is performed in the hydrothermal processing bench-scale reactor system. Slurries of biomass are prepared in the laboratory from whole ground biomass materials. Both wet processing and dry processing mills can be used, but the wet milling to final slurry is accomplished in a stirred ball mill filled with angle-cut stainless steel shot. The PNNL HTL system, as shown in the figure, is a continuous-flow system including a 1-litre stirred tank preheater/reactor, which can be connected to a 1-litre tubular reactor. The product is filtered at high-pressure to remove mineral precipitate before it is collected in the two high-pressure collectors, which allow the liquid products to be collected batchwise and recovered alternately from the process flow. The filter can be intermittently back-flushed as needed during the run to maintain operation. By-product gas is vented out the wet test meter for volume measurement and samples are collected for gas chromatography compositional analysis. The bio-oil product is analyzed for elemental content in order to calculate mass and elemental balances around the experiments. Detailed chemical analysis is performed by gas chromatography-mass spectrometry and 13-C nuclear magnetic resonance is used to evaluate functional group types in the bio-oil. Sufficient product is produced to allow subsequent catalytic hydroprocessing to produce liquid hydrocarbon fuels. The product bio-oil from hydrothermal liquefaction is typically a more viscous product compared to fast pyrolysis bio-oil. There are several reasons for this difference. The HTL bio-oil contains a lower level of oxygen because of more extensive secondary reaction of the pyrolysis products. There are less amounts of the many light oxygenates derived from the carbohydrate structures as they have been further reacted to phenolic Aldol condensation products. The bio-oil is more hydrophobic because of the lower oxygen content and resulting lower polarity and therefore has a lower amount of dissolved water. Without the light oxygenates acting as solvents along with the water, the bio-oil product is much more viscous. Related results are that the bio-oil is less dense and has a higher energy content. These differences in properties led to the earlier held belief that the HTL bio-oils could be upgraded by catalytic hydroprocessing in a manner more similar to simple petroleum hydrotreating. Some initial results from the HydroThermal Liquefaction of kelp are shown in Table 1. The experiments were performed with kelp slurries of 5-13 wt.% dry solids in water. Oil yields from kelp are low at 24% on ash-free basis but up to 41% calculated on a carbon basis. The bulk of the rest of the carbon ends up dissolved in the water stream.

02 PETROLEUM↗
DOE OSTI2011

241Am (n,gamma) isomer ratio measurement

The objective of this project is to improve the accuracy of the {sup 242}Cm/{sup 241}Am radiochemistry ratio. We have performed an activation experiment to measure the {sup 241}Am(n,{gamma}) cross section leading to either the ground state of {sup 242g}Am (t{sub 1/2} = 16 hr) which decays to {sup 242}Cm (t{sub 1/2} = 163 d) or the long-lived isomer {sup 242m}Am (t{sub 1/2} = 141 yr). This experiment will develop a new set of americium cross section evaluations that can be used with a measured {sup 242}Cm/{sup 241}Am radiochemical measurement for nuclear forensic purposes. This measurement is necessary to interpret the {sup 242}Cm/{sup 241}Am ratio because a good measurement of this neutron capture isomer ratio for {sup 241}Am does not exist. The targets were prepared in 2007 from {sup 241}Am purified from LANL stocks. Gold was added to the purified {sup 241}Am as an internal neutron fluence monitor. These targets were placed into a holder, packaged, and shipped to Forschungszentrum Karlsruhe, where they were irradiated at their Van de Graff facility in February 2008. One target was irradiated with {approx}25 keV quasimonoenergetic neutrons produced by the {sup 7}Li(p,n) reaction for 3 days and a second target was also irradiated for 3 days with {approx}500 keV neutrons. Because it will be necessary to separate the {sup 242}Cm from the {sup 241}Am in order to measure the amount of {sup 242}Cm by alpha spectrometry, research into methods for americium/curium separations were conducted concurrently. We found that anion exchange chromatography in methanol/nitric acid solutions produced good separations that could be completed in one day resulting in a sample with no residue. The samples were returned from Germany in July 2009 and were counted by gamma spectrometry. Chemical separations have commenced on the blank sample. Each sample will be spiked with {sup 244}Cm, dissolved and digested in nitric acid solutions. One third of each sample will be processed at a time. First, the gold will be removed by anion exchange chromatography. Then the {sup 242}Cm will be separated from the {sup 241}Am using the methanol/nitric acid anion exchange method. When a sufficient separation has been achieved, a deposit will be prepared and the {sup 242}Cm will be counted by alpha spectrometry. The purified {sup 241}Am fraction containing the long lived {sup 242m}Am will be allowed to decay into {sup 242}Cm for a period of {approx}6 months. After this time, the americium/curium separations will be repeated and the {sup 242}Cm that has grown in will be counted by alpha spectrometry. At the conclusion of the experiment, we will have cross section measurements for {sup 241}Am (n,{gamma}) {sup 242g}Am and {sup 241}Am (n,V) {sup 242m}Am at two energies.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2020

Oxidation of Glycolate in the Defense Waste Processing Facility (DWPF) Recycle Collection Tank - 20305

The Savannah River Site's Defense Waste Processing Facility (DWPF) operations are being upgraded with the introduction of the Nitric-Glycolic Flowsheet. Glycolic acid has been shown superior to formic acid as the reducing acid used during chemical processing. The new flowsheet improves or maintains necessary parameters such as 1) reduction of mercury, 2) adjustment of feed rheology and 3) adjustment of melter oxidation/reduction potential. Further, the potential for catalytic hydrogen generation in DWPF processing is virtually eliminated. DWPF process condensates are collected and returned to the SRS Concentration, Storage and Transfer Facilities (CSTF). The Recycle Collection Tank (RCT) collects off-gas condensate during chemical processing, vitrification, and other unit operations performed in DWPF and is the singular return vessel delivering recycle effluent back to CSTF. Each batch of recycle may contain a small amount of glycolate from chemical processing and melter off-gas condensates. To avoid potential flammability issues due to thermolysis of glycolate in the CSTF, chemical oxidation within the RCT has been investigated as an option for mitigating the transfer of glycolate. Sodium permanganate has been down-selected as the best option for oxidation of glycolate. Testing was performed using both 2-L and 22-L reactors (16,800:1 and 1,530:1 scale by volume) with non-radioactive waste simulants to approximate the expected RCT compositions. RCT simulants were evaluated at various process pH and temperature conditions. Also, RCT operations, namely the sequence of addition of corrosion inhibitors (NaOH and NaNO{sub 2}) versus a permanganate strike, were evaluated. Glycolate was introduced via a sludge simulant to mimic both expected entrainment and abnormal process foam-over conditions - the range being between 68 and 5100 mg/kg glycolate. Glycolate destruction was monitored by ion chromatography (IC). The corresponding manganese behavior was monitored in real-time using in situ ultraviolet-visible (UV-Vis) spectroscopy. RCT glycolate content can be reduced to below the IC detection limit within 90 minutes for all concentrations investigated. Ion Chromatography analysis revealed that under alkaline conditions, glycolate is primarily oxidized to oxalate with no significant formation of CO{sub 2} or carbonate, and nitrite is not oxidized to nitrate. Initially, complete oxidation of organics species and nitrite was assumed. Determination of the mechanistic chemical reaction has allowed the required amount of permanganate to be more accurately predicted and the total addition to be significantly reduced. UV-Vis measurements reveal that permanganate (Mn{sup 7+}) is reduced to manganate (Mn{sup 6+}) in the RCT. The oxidant stoichiometry is defined by using the initial permanganate to glycolate (P/G) molar ratio. At low initial glycolate concentration (68 and 140 mg/kg), the minimum required initial permanganate to glycolate (P/G) molar ratio was found to be 5-6. With high initial glycolate concentrations (5100 mg/kg) a lower (P/G) molar ratio of ∼2.5 was needed. The final portion of this effort supporting the nitric/glycolic flowsheet will be to test actual (fully radioactive) RCT samples as per the above simulant tests. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Solution‐Phase Dynamic Assembly of Permanently Interlocked Aryleneethynylene Cages through Alkyne Metathesis

Abstract Highly stable permanently interlocked aryleneethynylene molecular cages were synthesized from simple triyne monomers using dynamic alkyne metathesis. The interlocked complexes are predominantly formed in the reaction solution in the absence of any recognition motif and were isolated in a pure form using column chromatography. This study is the first example of the thermodynamically controlled solution‐phase synthesis of interlocked organic cages with high stability.

Wang, Qi↗