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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 1,045 records · Page 58

All sources NASA NTRS DOE OSTI

DOE OSTI2017

Concurrent Synthesis of High-Performance Monolayer Transition Metal Disulfides

To date, the chemical vapor deposition (CVD) approach has been widely used for the growth of transition metal dichalcogenides (TMDs). However, the reported CVD methods to synthesize TMDs cannot be used to grow more than one type of TMDs. This work reports a promising CVD technique to concurrently synthesize multiple monolayer transition metal disulfides once. The optoelectrical characterization and high-resolution transmission electron microscopy show the high quality of monolayer crystals, and, more importantly, there is no mixing between different precursors during the growth process, which has been investigated by considering the gas flow dynamics and concentration distribution of precursors in our setup. This strategy indicates the promising future for the batch production of 2D materials and the concurrent synthesis techniques in standard state-of-the-art complementary metal-oxide-semiconductor (CMOS) fabrication technology.

36 MATERIALS SCIENCE↗

DOE OSTI2019

Seasonal treatment and economic evaluation of an algal wastewater system for energy and nutrient recovery

Algal systems have been proposed for treating wastewater while simultaneously recovering energy and nutrients. In this study, an integrated system with algal treatment of municipal wastewater followed by hydrothermal liquefaction (HTL) conversion and upgrading steps was evaluated. Pilot-scale treatment of primary clarified municipal wastewater effluent was evaluated in different seasons (cold, warm, and a transitional period in between) with different strains of algae selected for each season, and the warm season strain successfully met all local discharge regulations. The collected wastewater algae biomass was subjected to HTL at 300 and 350 °C and both energy and nutrient recoveries were much improved at the higher temperature. The transitional batch was found to have the highest biocrude oil yields, and its co-products had the highest nutrient (nitrogen and phosphorus) contents. Economic analysis of conversion processes informed by the observed HTL product yields was conducted. While this revealed that targeting biofuel products alone was not profitable, adding nutrient co-products (e.g., ammonium sulfate fertilizer), adjusting algae harvesting time, and incorporating component-specific conversion processes could substantially improve system economics. Overall, this study highlights connections between treatment and conversion processes, and demonstrates how these connections can be leveraged for more efficient resource recovery without compromising treatment operations.

09 BIOMASS FUELS↗

DOE OSTI2016

Characterization of SuperLig® 639 rhenium and technetium resin with batch contact and column tests

Two new (2013) lots of SuperLig® 639 ion exchange resin (IBC Advanced Technologies, American Forks, UT) were tested for the first time above typical sodium concentrations (7.8 M sodium, along with typical 5 M concentration) in highly alkaline solutions. Batch contact and ion exchange column tests characterized rhenium (perrhenate) adsorption as a surrogate for pertechnetate. The work supports technetium removal options for Supplemental Low Activity Waste processing at the Hanford River Protection Project Waste Treatment Plant (WTP). The current work found that the resin performs well in the 7.8 M sodium simulant despite complete floating of the beads. A notable difference in performance between the two new resin lots was found. As a result, resin loading overall versus temperature, potassium concentration, and rhenium/nitrate ratios is consistent with previous data and expectations despite the high sodium concentration and floating of the resin beads.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2016

Towards a method of rapid extraction of strontium-90 from urine: urine pretreatment and alkali metal removal

A technical program to support the Centers of Disease Control and Prevention is being developed to provide an analytical method for rapid extraction of Sr-90 from urine, with the intent of assessing the general population’s exposure during an emergency response to a radiological terrorist event. Results are presented on the progress in urine sample preparation and chemical separation steps that provide an accurate and quantitative detection of Sr-90 based upon an automated column separation sequence and a liquid scintillation assay. Batch extractions were used to evaluate the urine pretreatment and the column separation efficiency and loading capacity based upon commercial, extractant-loaded resins. An efficient pretreatment process for decolorizing and removing organics from urine without measurable loss of radiostrontium from the sample was demonstrated. In addition, the Diphonix® resin shows promise for the removal of high concentrations of common strontium interferents in urine as a first separation step for Sr-90 analysis.

61 RADIATION PROTECTION AND DOSIMETRY↗

DOE OSTI2020

Chromatographic Modeling of 1-Foot Detritiation Test Column Results for the Optimization of Regeneration Time

This report documents the methods and results of a modeling study on a series of data generated by 1-foot test columns for the Water Detritiation project. In order to compliment modeling work already in progress on this project, a purely empirical curve-fitting approach is used in this study to determine chromatographic performance indicators such as retention time, curve width, and the number of chromatographic stages. The data used in this study comes from four sets of chromatographic test separations performed in March through May of 2017 using 1-foot columns. All are using the same flow rates and temperature (room temperature, nominally 25 C°). The first set of data (referred to in this report as the Column 1 data) is a series of twelve breakthrough curve measurements. Prior to each of these twelve runs, the column was regenerated by flowing hydrogen gas through the column, for increasing amounts of time, ranging from 2 hours to 25 hours. The second set of data (referred to as the Column 2 data) is comprised of five measurements of breakthrough curves measured in similar fashion as the Column 1 data, across a range of regeneration times from 2 to 21 hours. The third set of data (referred to as the Purge data) is of three breakthrough curves, measured after a regeneration time of 8 hours, which takes place after a nitrogen purge of 15, 30, or 45 minutes. The fourth data set is a series of five breakthrough curve measurements using a 2 nd batch of stationary phase, taken after regeneration times ranging from 2 to 20 hours. The overall modeling approach is as follows. First, the data is pre-processed for formatting, artifact removal, and is normalized. The data is then fit by integrated versions of four common chromatographic models. The best model is chosen based on the predictive performance of the model, and chromatographic performance values are calculated based on the best model’s fit parameters. Each of these processes are detailed below.

42 ENGINEERING↗

DOE OSTI2025

Small Scale Melter Testing of HLW Algorithm Glasses: Matrix 1 Tests

The principal objectives of the DM100 tests were to determine the effects of glass property extremes (glass viscosity, electrical conductivity, and T1%), minimum and maximum concentrations of several major and minor glass components, +/-15% batching errors in the addition of Glass Forming Chemicals (GFCs) to the feed, and variation in the sources of boron and sodium used in the GFCs on processing rates and melter conditions (off-gas characteristics, glass processing, foaming, cold cap, etc.) at constant bubbling rate.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS2001

Cyrano "Nose" The Smell of Success

Cyrano Sciences, Inc. has commercialized a simple, accurate, non- invasive tool that enables "machines to smell". The Cyranose 320 is used for quality control purposes in the food and chemical industries. Using a sensor array and onboard pattern recognition algorithms, the lightweight, portable device works by exposing an array of polymer composite sensors to the chemical components in a vapor. When the sensors come in contact with the vapor, the polymer expands like a sponge, changing the resistance of the composites. The change in resistance is measured, and from that measurement, the presence of a pre-trained substance is determined with a quick and accurate diagnosis. This real-time, portable device enables food companies to spot test raw materials for batch-to-batch consistency, spoilage, or contamination. The Cyranose 320 is also used by chemical and petrochemical companies for quick assessment of the chemical status associated with various industrial processes. Profiling a chemical environment in a hazardous materials situation allows emergency crews to accurately select fire retardants, containment strategies, and protective gear. Future applications for the Cyranose 320 are fast growing and other uses of this technology are on the horizon.

Source record↗

DOE OSTI2015

The effect of thermal treatment of hematite ore for chemical looping combustion of methane

For chemical looping processes to become an economically viable technology, an inexpensive carrier that can endure repeated reduction and oxidation cycles needs to be identified or developed. Unfortunately, the reduction of hematite ore with methane in both batch and fluidized beds has revealed that the performance (methane conversion) decreases with time. Previous analysis had shown that the grains within the particle grew with the net effect of reducing the surface area of the particles and thereby reducing the rate and net conversion for a fixed reduction time. To improve the lifespan of hematite ore, it is hypothesized that if the grain size could be stabilized, then the conversion could be stabilized. In this work, series of tests were conducted in an electrically heated fluidized bed. The hematite ore was first pretreated at a temperature higher than the subsequent reduction temperatures. After pretreatment, the hematite ore was subjected to a series of cyclic reduction/oxidation experiments. Furthermore, the results show that the ore can be stabilized for cycles at different conditions up to the pretreatment temperature without any degradation. Details of the pretreatment process and the test results will be presented.

42 ENGINEERING↗

DOE OSTI2018

In Situ Synthesized Hydroxyapatite—Cellulose Nanofibrils as Biosorbents for Heavy Metal Ions Removal

The synthesis of hydroxyapatite (HAp) in the presence of cellulose nanofibrils (CNF) or TEMPO-oxidized CNF (TCNF) was performed in situ by wet chemical precipitation process, using chemical precursors, to hybrid a low-cost biosorbents for removal of Co{sup 2+} as a model heavy metal ion. The removal is investigated by batch adsorption method depending on the pH value, the dosage of adsorbent, initial Co{sup 2+} concentration and the contact time of adsorption. The removal of Co{sup 2+} reached the maximum (87%) at pH 6 by using a dosage of 0.5 g L{sup −1}. The TCNFs is shown to increase the nucleation and growth of the HAp synthesized, providing higher surface area (138 m{sup 2} g{sup −1}) with lower pore diameter (11.89 nm), compared to the CNFs based hybrid (135 m{sup 2} g{sup −1}, 14.42 nm) or pure HAp (118 m{sup 2} g{sup −1}, 13.32 nm), however, both resulting to a higher adsorption capacity (25 mg g{sup −1}) of Co{sup 2+} compared to HAp or TCNF (20–22 mg g{sup −1}). The adsorption is follows primarily by pseudo-first and Elovic order kinetic models which is due to the physisorption of Co{sup 2+} and surface ionic interactions with available negative phosphate (from HAp) and/or carboxylic (from TCNF) groups, fitting well with the Freundlich adsorption isotherm, and secondly due to the ion-exchange mechanism of Co{sup 2+} with Ca{sup 2+} from HAp. Both hybrid adsorbents show good adsorption (≥40%) capacity even after third reusing cycle, and high temperature stability (weight loss of 14%) up to 1000 °C, however, the CNF-HAp hybrid represent a high-value alternative to relatively costly TCNF.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2019

Environmentally Benign and Scalable Preparation of Diethyl Furoxan-3,4-dicarboxylate Using Silver Carbonate as a Nitrile Oxide Generator

Diethyl furoxan-3,4-dicarboxylate (1) is a starting material for many heterocyclic compounds containing furoxan and furazan rings. Usually, furoxan 1 was prepared via a dimerization of corresponding nitrile oxide generated either by treatment of ethyl 2-chloro-2-(hydroxyimino)-acetate (2) with triethylamine or by nitration or conversion of α-activated ethyl acetate with acetyl nitrate in acetic acid or other catalytic reagents. Both methods are suitable for small-scale but suffered from various drawbacks for large-scale preparation. Years ago, a general method for the preparation of furoxan from corresponding hydroximidoyl chloride (R–CCl=NOH) with silver carbonate (Ag 2 CO 3 ) was developed in our group. Now this method is extended to prepare 1 from 2. The synthesis involves the treatment of 2 with Ag 2 CO 3 in THF at room temperature, with a 3–4 h reaction time, with a yield of 80–90%. Using this method, a one pound batch of the material has been prepared at the lab-scale, but the preparation should be easily scaled to the multikilogram synthesis. This is an environmentally benign process since the preparation generates little hazardous wastes due to the possible recycling of the solvent, THF, and the byproduct, silver chloride.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

High-pressure CO 2 dissociation with nanosecond pulsed discharges

Herein we investigate the conversion of CO 2 into CO and O 2 with nanosecond repetitively pulsed (NRP) discharges in a high-pressure batch reactor. Stable discharges are obtained at up to 12 bar. By-products are measured with gas chromatography. The energy efficiency is determined for a range of processing times, pulse energy, and fill pressures. It is only weakly sensitive to the plasma operating parameters, i.e the extent of CO 2 conversion is almost linearly-dependent on the specific energy invested. A conversion rate as high as 14% is achieved with an energy efficiency of 23%. For long processing times, saturation in the yield and a drop in efficiency are observed, due to the increasing role of three-body recombination reactions, as described by zero-dimensional detailed kinetic modeling. The modeling reveals the presence of three-stage kinetics between NRP pulses, controlled by electron-impact CO 2 dissociation, vibrational relaxation, and neutral elementary kinetics. Transport effects are shown to be important for CO 2 conversion at high pressures. For fill pressures beyond 10 bar, CO 2 may locally transit into supercritical states. The supercritical plasma kinetics may bypass atomic oxygen pathways and directly convert CO 2 into O 2 . This work provides a detailed analysis of plasma-based high-pressure CO 2 conversion, which is of great relevance to future large-scale sustainable carbon capture, utilization, and storage.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2017

Comparison of Electrostatic and Non-Electrostatic Models for U(VI) Sorption on Aquifer Sediments

We report that a non-electrostatic generalized composite surface complexation model (SCM) was developed for U(VI) sorption on contaminated F-Area sediments from the U.S. Department of Energy Savannah River Site, South Carolina. The objective of this study was to test if a simpler, semi-empirical, non-electrostatic U(VI) sorption model (NEM) could achieve the same predictive performance as a SCM with electrostatic correction terms in describing U(VI) plume evolution and long-term mobility. One-dimensional reactive transport simulations considering key hydrodynamic processes, Al and Fe minerals, as well as H + and U surface complexation, with and without electrostatic correction terms, were conducted. The NEM was first calibrated with laboratory batch H + and U(VI) sorption data on F-Area sediments, and then the surface area of the NEM was adjusted to match field observations of dissolved U(VI). Modeling results indicate that the calibrated NEM was able to perform as well as the previously developed electrostatic model in predicting the long-term evolution of H + and U(VI) at the site, given the variability of field-site data. The electrostatic and NEM models yield somewhat different results for the time period when basin discharge was active; however, it is not clear which modeling approach may be better to model this early time period because groundwater quality data during this period were not available. Lastly, a key finding of this study is that the applicability of NEM (and thus robustness of its predictions) to the field system evolves with time and is strongly dependent on the pH range that was used to develop the model.

58 GEOSCIENCES↗

DOE OSTI2016

Coalescence in PLA-PBAT blends under shear flow: Effects of blend preparation and PLA molecular weight

Blends containing 75 wt. % of an amorphous polylactide (PLA) with two different molecular weights and 25 wt. % of a poly[(butylene adipate)-co-terephthalate] (PBAT) were prepared using either a Brabender batch mixer or a twin-screw extruder. These compounds were selected because blending PLA with PBAT can overcome various drawbacks of PLA such as its brittleness and processability limitations. In this study, we investigated the effects of varying the molecular weight of the PLA matrix and of two different mixing processes on the blend morphology and, further, on droplet coalescence during shearing. The rheological properties of these blends were investigated and the interfacial properties were analyzed using the Palierne emulsion model. Droplet coalescence was investigated by applying shear flows of 0.05 and 0.20 s{sup −1} at a fixed strain of 60. Subsequently, small amplitude oscillatory shear tests were conducted to investigate changes in the viscoelastic properties. The morphology of the blends was also examined using scanning electron microscope (SEM) micrographs. It was observed that the PBAT droplets were much smaller when twin-screw extrusion was used for the blend preparation. Shearing at 0.05 s{sup −1} induced significant droplet coalescence in all blends, but coalescence and changes in the viscoelastic properties were much more pronounced for the PLA-PBAT blend based on a lower molecular weight PLA. The viscoelastic responses were also somehow affected by the thermal degradation of the PLA matrix during the experiments.

36 MATERIALS SCIENCE↗

DOE OSTI2017

Assessment of a Filtration Waste Qualification Method for LAWPS

The Low-Activity Waste Pretreatment System (LAWPS) facility is planned to pretreat Hanford tank waste supernate by filtering solids and processing through ion exchange columns to remove cesium. The filtration process is achieved through cross flow filtration using a stainless steel Mott filter with a 0.1-micron grade. The goal of this effort was to assess whether a batch, or dead end, filtration (DEF) device replicating the LAWPS cross flow filter could be employed to qualify each feed campaign prior to delivery to LAWPS. The objective for filtration feed qualification is to determine whether the cross-flow filters deployed in LAWPS will remove solids while maintaining a de minimus flow rate of permeate. To that end, the DEF was tested with simulants and the results compared with those obtained from cross flow filtration tests.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2021

VERSE-LC TCCR Model Calibration using Batch 1A, Batch 2, and Batch 3 Column Data

The objective of this work is to utilize on-line gamma monitoring data collected during Tank Closure Cesium Removal (TCCR) Column Batch 3 operations to calibrate the parameters (essentially, the correction/dilution factors (CF or DF)) used in the VERSE-LC models for the prediction of cesium breakthrough while processing Savannah River Site (SRS) Tank 10H dissolved saltcake High-Level Waste through a packed cylindrical bed of Crystalline Silicotitanate (CST). Calibrated VERSE-LC models could be applied to aid in evaluating future TCCR operations.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2024

Direct Feed High-Level Waste APPS Model Glass Testing (DFHLW APPS) Matrix

This report summarizes the data collected during the batching and melting of the Direct Feed High-Level Waste APPS Model Glass Matrix (DFHLW APPS) to serve as a quality-assured validation of the Aspen Process Performance Simulation (APPS) formulation method. Of 15 glasses tested, 12 satisfied all target property constraints. Two glasses, APPS-05 and -06, formed nepheline on canister centerline cooling heat-treatment and failed the Product Consistency Test response limits. Glass APPS-07-2 formed unacceptably high concentrations of crystals (primarily Na3Nd(PO4)2) when heat treated at 950 °C. All other glasses were found to be satisfactory. The measured property values were compared to predicted values from a set of current models. In many cases the current models were found to be inadequate for design of DFHLW glasses. These models are being adjusted to correct for mispredictions. Other models, e.g., density, toxicity characteristic leaching procedure, and sulfur solubility, are adequate for formulation of DFHLW glasses.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1972

Mini-arc orbit determination for the Geos C altimetry experiment.

The problem is, given simultaneous observations of an altimeter-bearing geodetic satellite, from three or more high-precision radar stations, to determine its orbit to submeter accuracy in the presence of perturbations arising from strong, localized gravitational anomalies. A new solution to this problem involves the use of an f and g series specialized to the determination of radial distance (pertinent to the satellite altimeter experiment) to process data over a very short arc (e.g., 6 sec to 10 min). Such a short arc is termed a 'mini-arc.' In this approach, the data batches are connected by dynamics, rather than by the usual curve fit to a power series in time. A nonunity value of the mass factor is introduced to serve as an 'alias' for the perturbations that affect the satellite's path during the mini arc. The essence of the mini-arc approach is to include the influence of the far, or relatively lower-order, force field analytically and to solve for the remaining fine structure with accuracies that can approach a few centimeters.

Baker, R. M. L., Jr.↗

NASA NTRS1981

Failure of morphology of (0 deg)8 graphite/epoxy as influenced by environments and processing

Optical and scanning electron microscopy were used to investigate the failure morphology of graphite/epoxy specimens which had been tested until tensile failure. Failure morphology was studied as a function of the quality control variables of specimen preparation technique, prepreg batch, and cure condition, and also as a function of the environmental parameters of temperature and moisture content. Defective specimens were found to exhibit a low energy failure morphology. Poor specimen edge preparation and one batch of prepreg when tested at elevated temperature or moisture content also exhibited energy failure morphology. Postcuring had no effect on strength but did slightly alter failure morphology. Temperature or moisture appeared to decrease flaw sensitivity and thus increase strength; however, moisture also appeared to increase interfacial debonding between filament and matrix. When combined moisture and temperature increased interfacial debonding and made the epoxy matrix more prone to fracture.

Clements, L. L.↗