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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Combining Reclaimed PET with Bio-Based Monomers Enables Plastics Upcycling

Less than 30% of PET plastic is recycled in the United States. The low reclamation rate may be due to mechanical recycling accounting for the majority of commercial PET recycling. Mechanical recycling yields a lower-quality recycled plastic than the process of chemically recycling back to the monomer phase, which can be energetically and economically expensive. In this work, recently published in Joule, reclaimed PET bottles are chemically recycled and converted into higher-value fiberglass-reinforced plastics (FRPs).This presentation will focus on the supply-chain level energy and greenhouse gas emissions intensities associated with this novel upcycling route. The Materials Flows through Industry supply chain analysis tool, developed at NREL, is used to estimate these impacts. Depending on the extent and speed of adoption, this strategy for plastic upcycling could lead to significant energy usage and emissions reductions over the traditional FRP supply chain. Overall, this approach may provide an economic incentive for plastics recycling and renewable feedstock use through the creation of higher-value FRPs.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2022

Majorana modes with side features in magnet-superconductor hybrid systems

Magnet-superconductor hybrid (MSH) systems represent promising platforms to host Majorana zero modes (MZMs), the elemental building blocks for fault-tolerant quantum computers. Theoretical description of such MSH structures is mostly based on simplified models, not accounting for the complexity of real materials. Here, based on density functional theory, we derive a superconducting 80-band model to study an MSH system consisting of a magnetic manganese chain on the s wave superconductor niobium. For a wide range of values of the superconducting order parameter, the system is a topological superconductor, with MZMs exhibiting non-universal spatial patterns and a drastic accumulation of spectral weight on both sides along the magnetic chain. These side feature states can be explained by an effective model which is guided by the ab initio results. Performing scanning tunneling spectroscopy experiments on the same system, we observe a spatial structure in the low-energy local density of states that is consistent with the theoretical findings. Our results open a first-principle approach to the discovery of topological superconductors.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Colorado State University (CSU) X-Band Precipitation Radar Plan Position Indicator Data Processed with Corrected Moments in Antenna Coordinates (CMAC) Value-Added Product Report

In 2010 the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) user facility procured 3- and 5-cm wavelength radars for documenting the macrophysical, microphysical, and dynamical structure of precipitating systems. To maximize the scientific impact, ARM supported the development of an application chain to correct for various phenomena in order to retrieve the “point” values of moments of the radar spectrum and polarimetric measurements. We have now used the lessons learned from the processing of the 3- and 5-cm wavelength radars obtained by ARM to help process X-band radar data from the Surface Atmospheric Integrated Field Laboratory (SAIL) field campaign. This report details the motivation, science, and progress to date as well as charting a path forward.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Machine learning-based discovery of molecular descriptors that control polymer gas permeation

While machine learning has found increasing use in predicting the properties of polymeric materials with only a knowledge of chain architecture, determining the molecular factors underpinning properties (“interpretable AI”) has remained less well explored. We show that encoding chain chemistry in commonly employed formats, e.g., binary-valued fingerprints, leads to uniqueness issues during the hashing process to save storage space. This is because the hashing algorithm can map several chemical moieties into the same bit. These issues carry over into the ML algorithms, especially for “inverse” design and interpretable AI, and cannot be avoided by changing the length of the fingerprint. Using MACCS key featurizations of monomer repeats resolves some of these issues, and we show that a few substructures consistently appear in top features for maximizing permeability across several gases and ML models. These are carbon–carbon double bonds (as in polyacetylenes) especially when they are associated with methyl groups (found in branching architectures). Here these results, derived from the limited data set of ~ 500 polymers with experimental gas permeation data, are in agreement with physical insight and thus provide a robust foundation which could further enable study of these material classes through detailed experiments and simulations.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Enhanced Softwood Cellulose Accessibility by H 3 PO 4 Pretreatment: High Sugar Yield without Compromising Lignin Integrity

Softwood lignocellulose is a potential feedstock for the production of biofuels and bioproducts. However, the highly cross-linked nature of softwood lignocellulose restricts enzyme access to its sugars. Thus, harsh pretreatment conditions (180–280 °C) and/or high enzyme loading are required to unlock sugars. These requirements negatively affect the economic viability of softwoods in biorefineries. Here we show that H 3 PO 4 pretreatment of pine and Douglas fir under a mild reaction temperature (50 °C) and atmospheric pressure enabled a high (~80%) glucan digestibility with low enzyme loading (5 filter paper units (FPU)/g glucan). The dissolution and regeneration of softwoods disrupted the hydrogen bonding between cellulose chains, thereby increasing the cellulose accessibility to cellulase (CAC) values by ~38-fold (from ~0.4 to 15 m 2 /g biomass). Examination of H 3 PO 4 -pretreated softwoods by cross-polarization/magic angle spin (CP/MAS), 13 C- nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FTIR) revealed that breaking of the orderly hydrogen bonding of crystalline cellulose caused the increase in CAC (higher than 11 m 2 /g biomass), which, in turn, was responsible for the high glucan digestibility of pretreated softwoods. The H 3 PO 4 pretreatment process was feedstock independent. Finally, 2D 13 C– 1 H heteronuclear single quantum coherence (HSQC) NMR showed that the lignin was depolymerized but not condensed; thus, the lignin can be available for producing high-value products.

09 BIOMASS FUELS↗
DOE OSTI2024

Extracted Radar Columns and In Situ Sensors (RadCLss) Value-Added Product Report

In order to validate precipitation, in 2010 the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) user facility procured 3- and 5-cm wavelength radars for documenting the macrophysical, microphysical, and dynamical structure of precipitating systems. To maximize the scientific impact, ARM supported the development of an application chain to correct for various phenomena in order to retrieve the “point” values of moments of the radar spectrum and polarimetric measurements. In estimation from ARM radars, a workflow was created to directly compare radar “point” values with various in situ observations at the surface.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Anomalously strong viscosity behavior in mixed oxy-sulfide Na 4 P 2 S 7-x O x invert glasses

In this paper, the first observations have been made of anomalously strong viscosity behavior and correspondingly strong bulk glass formation and resistance to crystallization in a melt quenched (MQ) prepared series of invert, modifier content greater than the glass former content, mixed oxy-sulfide Na 4 P 2 S 7-x O x , 0 ≤ x ≤ 5, (NaPSO) glasses. We find that these glasses even with 67 mole % modifier, Na 2 S, and only 33 mole% glass former P 2 S 5-x O x , exhibit a calorimetric fragility index, m cal , as small as 29 compared to typical values of ~ 60 to 80 for alkali silicate glasses with > 50 mole% SiO 2 and the theoretical minimum m cal of ~ 15. The m cal values were converted to kinetic viscosity fragility, m vis , values and used with the measured glass transition temperatures, T g s, to produce viscosity curves for the glasses using the Mauro-Yue-Ellison-Gupta-Allan (MYEGA) model. The viscosity of the glass with a minimum m cal value of x = 2.5 was then shown to exhibit a viscosity that was as strong as, and for some compositions stronger than, the viscosity of alkali aluminosilicate glasses which have three dimensional network structures compared to the one dimensional chain structures observed in these MOS invert glasses. Consistent with these small values of fragility indices and therefore predicted higher viscosity above the glass transition temperature, T g , in the supercooled liquid regime, these glasses are also particularly resistant to crystallization. For example, the x = 2.5 glass composition exhibits a crystallization temperature, T C , more than 150K above its T g . We find that the calorimetric fragility of these glasses varies systematically with the extent of network forming bridging oxygens (BOs) in the glasses. The structural change caused by incrementally replacing sulfur with oxygen has been found to have consistent, large effects on the thermal properties.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Human health benefits of very-long-chain polyunsaturated fatty acids from microalgae

Microalgae are single-cell, photosynthetic organisms whose biodiversity places them at the forefront of biological producers of high-value molecules including lipids and pigments. Some of these organisms particular are capable of synthesizing n-3 very long chain polyunsaturated fatty acids (VLC-PUFAs), known to have beneficial effects on human health. Indeed, VLC-PUFAs are the precursors of many signaling molecules in humans involved in the complexities of inflammatory processes. Herein, this mini-review provides an inventory of knowledge on the synthesis of VLC-PUFAs in microalgae and on the diversity of signaling molecules (prostanoids, leukotrienes, SPMs, EFOX, isoprostanoids) that arise in humans from VLC-PUFAs.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Revision of Fission Yields Uncertainties in ENDF/B-VIII.0

The spontaneous and neutron-induced fission yield sublibraries in the Evaluated Nuclear Data Files (ENDF/B) contain cumulative and independent fission yield values for dozens of fissioning systems, and hundreds of fission products. In this work, we report on a correction step that was undertaken after observing anomalously large uncertainties for several end-of-chain fission products. A total of 17 cumulative fission yield uncertainties and the value of 2 independent yields were corrected as a result of this revision.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

SAIL Field Campaign X-Band Precipitation Radar Surface Quantitative Precipitation Estimation (SQUIRE) Value-Added Product Report

In 2010, the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility procured 3- and 5-cm wavelength radars for documenting the macrophysical, microphysical, and dynamical structure of precipitating systems. In order to maximize the scientific impact, ARM supported the development of an application chain to correct for various phenomena in order to retrieve the lowest retrieved value on a Cartesian grid. This report details the motivation, science, and progress to date, as well as charting a path forward.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Air Exchange Rate Impact on Activity Equilibrium Factors and Inhalation Fractional Equilibrium Factors for Rn, Xe, Kr, Ar, Ne, and Their Progeny in Vapor Intrusion, Risk, and Dose Models

Exposure to the radioactive noble gasses, especially radon, is of high concern and poses a significant risk to humans in an indoor air environment as the second leading cause of lung cancer in the United States. To evaluate and minimize the risks posed by these gasses, it is important to understand their radiological and physical properties. The EPA’s Radon Vapor Intrusion Screening Level (RVISL) calculator calculates indoor air RVISLs based on target working levels (WLs), target excess lifetime cancer risk (ELCR), and annual dose limits for the actinon (Rn-219), thoron (Rn-220), and radon (Rn-222) decay series. The RVISLs are based on inhalation and submersion in gas cloud exposure routes for residential and commercial settings. The RVISLs are analogous to preliminary remediation goals (PRGs) and dose compliance concentrations (DCCs), where the isotope-specific values are in units of activity concentration (activity per unit volume). If the concentration of a parent isotope of radon or its progeny is found to exceed the RVISL, then further action to ensure cleanup of the contaminant may be necessary. In residential and commercial settings, the RVISLs will vary based on the air exchange rate present. The EPA’s Radionuclide PRG and DCC Calculators also assess the risk/dose from noble gases in the air due to household use of water like showering. In this study, a computational method in MATLAB was developed to determine the impact of the air exchange rate on the activity equilibrium factor (A eq ) and the inhalation fractional equilibrium factor (F eq ). Both factors are values that reflect the equilibrium concentrations of progeny to their parent in the air. These factors have a direct impact on the RVISL, PRG, and DCC calculations of WL, ELCR, and annual dose, respectively. This study builds on a previous report that only focused on actinon, thoron, and radon by revisiting the original A eq and F eq calculation methods, as well as including the values for the Rn-207, Rn-209, Rn-210, Rn-211, Rn-215, Rn-216, Rn-217, Rn-218, Rn-223, Ne-24, Ar-42, Ar-43, Ar-44, Kr-74, Kr-75, Kr-76, Kr-77, Kr-88, Kr-89, Xe-120, Xe-121, Xe-122, Xe-123, Xe-135m, and Xe-138 decay chains, which are not currently available in literature. The EPA’s RVISL calculator will be updated to include the new A eq and F eq values for the actinon, thoron, and radon decay chains, while the rest of the calculators will incorporate all the new A eq and F eq values as appropriate.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2022

Life cycle assessment of utilizing freshly cut urban wood: A case study

Large amounts of urban wood resources are generated through tree removals in urban areas. Therefore, there is a growing interest to improve the environmental performance of the urban wood supply chain by quantifying the environmental impacts of creating high-value products from urban tree removals to enhance its utilization. By surveying existing urban wood utilization operations for primary data in two major cities: Baltimore, Maryland, and Milwaukee, Wisconsin, a new life cycle inventory (LCI) dataset per m 3 of dry urban hardwood lumber and live edge slabs was created. Incorporating the new LCI data into life cycle assessment method, the total global warming (GW) impact of converting urban trees to kiln-dried lumber was estimated to be 122 kg CO 2 eq and 336 kg CO 2 eq per m 3 of lumber produced for Baltimore and Milwaukee, respectively. In both cases, the total environmental impact of the product was dominated by the conversion of urban trees to kiln dried lumber at the sawmill processing stage. Using scenario analysis for the source of heat generation used in kiln (force) drying wood, substituting wood fuel from coproducts for natural gas in a boiler for Milwaukee resulted in a substantial reduction in fossil-derived GW impact. Urban and traditional hardwood lumber production follow similar GW impact trajectories over their life-cycle stages with the lumber processing stage having the highest environmental impacts for both. Finally, increasing the overall lumber yield and decreasing kiln (force) drying would substantially improve the environmental performance of urban hardwood lumber and help make it comparable to traditional lumber.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

How Cerium and Lanthanum as Coproducts Promote Stable Rare Earth Production and New Alloys

The largest outputs of rare earth mining are the low-value byproducts cerium and lanthanum, which burden rare earth supply chains because they must be separated from more desirable rare earths used in magnet production. Promoting demand for cerium and lanthanum can potentially diversify the economics of rare earth mining and improve supply chain stability for all rare earth elements. A promising avenue for increasing byproduct rare earth element demand is their use in aluminum alloys; an application for cerium and lanthanum offering multiple benefits to manufacturing such as energy reduction and improved throughput. Experimental materials science and economic implications of Al-rare earth element alloys will be discussed. We show that Al–La/Ce alloys have elevated mechanical strength compared to more traditional aluminum alloys, in some formulations can be used without heat treatment, and possess a highly castable eutectic microstructure. This report presents the use of cerium and lanthanum in aluminum alloys as an example of how supply chain focused approaches to technological development can benefit stakeholders at every step in production.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Mechanisms of direct and converse piezoelectricity in ferroelectric polymers

Within the linear regime of mechanical and electrical responses, it is commonly accepted that direct and converse piezoelectric coefficients should be the same. However, we observed a consistently higher converse d 31 (∼54 pm/V) than the direct d 31 (∼42 pC/N) for a quenched, stretched, annealed, and electrically poled poly(vinylidene fluoride-co-trifluorethylene) [P(VDF-TrFE)] 52/48 mol.% sample (abbreviated as coP-52/48QSAP). On the contrary, the direct and converse d 31 values were the same for coP-65/35QSAP and coP-55/45QSAP. Small-angle X-ray scattering results showed that coP-52/48QSAP had a higher amount of relaxor-like secondary crystals (SCs) in the oriented amorphous fraction (OAF) (SC OAF ) than coP-55/45QSAP and coP-65/35QSAP. To explain the experimental observation, we performed molecular dynamics (MD) simulation of the pure PVDF (without TrFE) to estimate direct and converse piezoelectricity for the PVDF OAF. Based on the MD simulation, the direct d 31 had a plateau value around 350 pC/N for the transverse (i.e., along the chain direction) strain up to 1 %, whereas the simulated converse d 31 could be lower (for electric field E < 0.8 MV/m), equal (for E = 0.8 MV/m), or higher (for E > 0.8 MV/m) than the direct d 31 , depending on the poling electric field. From the MD simulation, both mechano-electrostriction and electrostatic interaction were identified in the OAF as the driving force for enhanced piezoelectricity in ferroelectric PVDF. In conclusion, when ferroelectric domains were formed in the OAF by electric poling, the simulated converse d 31 became higher than the direct d 31 . Combining both experimental and MD simulation results, the higher converse d 31 than direct d 31 for coP-52/48QSAP was understood qualitatively.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Temperature-Dependent Constrained Diffusion of Micro-Confined Alkylimidazolium Chloride Ionic Liquids

Alkylimidazolium chloride ionic liquids (ILs) have many uses in a variety of separation systems, including micro-confined separation systems. To understand the separation mechanism in these systems, the diffusion properties of analytes in ILs under relevant operating conditions, including micro-confinement dimension and temperature, should be known. For example, separation efficiencies for various IL-based microextraction techniques are dependent on the sample volume and temperature. Temperature-dependent (20–100 °C) fluorescence recovery after photobleaching (FRAP) was utilized to determine the diffusion properties of a zwitterionic, hydrophilic dye, ATTO 647, in alkylimidazolium chloride ILs in micro-confined geometries. These micro-confined geometries were generated by sandwiching the IL between glass substrates that were separated by ~1 to 100 μm. From the measured temperature-dependent FRAP data, we note alkyl chain length-, thickness-, and temperature-dependent diffusion coefficients, with values ranging from 0.021 to 46 μm 2 /s. Deviations from Brownian diffusion are observed at lower temperatures and increasingly less so at elevated temperatures; the differences are attributed to alterations in intermolecular interactions that reduce temperature-dependent nanoscale structural heterogeneities. Furthermore, the temperature- and thickness-dependent data provide a useful foundation for efficient design of micro-confined IL separation systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Anionic Surfactants from Reactive Separation of Hydrocarbons Derived from Polyethylene Upcycling

Chemical upcycling of polyethylene (PE) to long-chain alkylaromatics through tandem hydrocracking/aromatization has potential to provide value-added chemicals. However, the liquid product is a complex mixture of alkanes, alkylbenzenes, and polyaromatics, limiting its direct usability. The most valuable component of the product mixture is the alkylbenzenes because of their potential as precursors to anionic surfactants. In this study, a one-pot reactive separation is described. Sulfonating the product mixture from PE upcycling with silica sulfuric acid followed by neutralization with sodium hydroxide yields sodium alkylbenzenesulfonates (up to 93 mol % selectivity), along with a separate phase of lubricant-range hydrocarbons as a coproduct. Compared to petroleum-based sodium dodecylbenzenesulfonates, the reported PE-derived surfactant molecules show competitive physicochemical properties, including surface tension and interfacial tension. According to life cycle assessment, the described reaction strategy demonstrates 20% lower greenhouse gas emissions, when considering uses for the coproducts of PE upcycling, compared to conventional linear alkylbenzenesulfonates (LAS) manufacturing directly from petrochemical feedstocks.

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

Sensitivity of modelled passive margin stratigraphy to variations in sea level, sediment supply and subsidence

Abstract We produced a 10 Myr synthetic stratigraphic section using a forward stratigraphic model that generates marine deltaic stratigraphy over geological timescales. We recursively fit the model using a Bayesian inversion algorithm to test: (1) if it could be accurately reconstructed; (2) if the parameters used to create it could be recovered; and (3) the sensitivity of the model output to given model parameters and the attendant physical processes. The original synthetic stratigraphic section was produced with cyclical sea‐level variations of 40 and 30 m with 2.4 and 10 Myr periods respectively. Sediment was also supplied cyclically, in 2.4 and 10 Myr cycles with amplitudes of 30 and 80 tons/100 kyr, respectively, varying from a mean of 232 tons/100 kyr. Parameter values were sampled to fit the model using a Markov chain Monte Carlo algorithm, resulting in a ±5 m (1σ) variation between the experimental output and the original. Sea level varied by ±7 m (1σ) within the posterior distribution of parameters. As a result, both the 10 Myr and 2.4 Myr sea‐level cycles could be extracted from the original output. The variation in sediment supply was approximately ±38 tons/100 kyr (1σ) and, as a result, only the larger long‐term supply variations could be accurately recovered in refitting the model. The variation in thermal, flexural and total subsidence across those parameter sets is less than ±10 m (1σ). The original section experienced 150 m of total subsidence at the depocentre. Our results demonstrate the distinct and interpretable imprint of sea level and subsidence on continental margin stratigraphy can be quantified. Moreover, we conclude that sea‐level change produces a defined effect on the geometries of stratigraphic architecture, and that techniques applied for the purpose of delineating sea‐level variation from continental margin strata have a well‐founded conceptual basis.

Schmelz, William J.↗
DOE OSTI2022

Establishing Butyribacterium methylotrophicum as a Platform Organism for the Production of Biocommodities from Liquid C 1 Metabolites

Using the Wood-Ljungdahl pathway, acetogens can nonphotosynthetically fix gaseous C 1 molecules, preventing them from entering the atmosphere. Many acetogens can also grow on liquid C 1 compounds such as formate and methanol, which avoid the storage and mass transfer issues associated with gaseous C 1 compounds. Substrate redox state also plays an important role in acetogen metabolism and can modulate products formed by these organisms. Butyribacterium methylotrophicum is an acetogen known for its ability to synthesize longer-chained molecules such as butyrate and butanol, which have significantly higher values than acetate or ethanol, from one-carbon (C 1 ) compounds. We explored B. methylotrophicum’s C 1 metabolism by varying substrates, substrate concentrations, and substrate feeding strategies to improve four-carbon product titers. Our results showed that formate utilization by B. methylotrophicum favored acetate production and methanol utilization favored butyrate production. Cofeeding of both substrates produced a high butyrate titer of 4 g/liter when methanol was supplied in excess to formate. Testing of formate feeding strategies, in the presence of methanol, led to further increases in the butyrate to acetate ratio. Mixotrophic growth of liquid and gaseous C 1 substrates expanded the B. methylotrophicum product profile, as ethanol, butanol, and lactate were produced under these conditions. We also showed that B. methylotrophicum is capable of producing caproate, a six-carbon product, presumably through chain elongation cycles of the reverse β-oxidation pathway. Furthermore, we demonstrated butanol production via heterologous gene expression. Finally, our results indicate that both selection of appropriate substrates and genetic engineering play important roles in determining titers of desired products.

09 BIOMASS FUELS↗