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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Development of a Small Liquid Sodium Purification Loop

Generation IV nuclear reactors provide management solutions to address spent fuel problems. The most researched Generation IV reactor is the sodium cooled fast reactor (SFR). Improved engineering is has allowed for systematic improvements in both the safety and efficiency of power production. However, before a SFR can be brought back online in the Untied States, constructive research must be pursued on numerous scales to ensure the capabilities of aforementioned reactors. While larger research facilities such as the one at Argonne National Laboratory or the University of Wisconsin - Madison address some of the larger scale studies surrounding the SFR, Fort Lewis College (FLC) is aiming to provide small scale studies on liquid sodium as a thermal hydraulic cooling system. The sodium diagnostic loop at FLC is constructed to conduct research that includes: analyzing pumping characteristics, thermal stratification, freeze plug analysis, and corrosion studies. The FLC loop is attached to an inert glovebox so these experiments can be conducted with an additional layer of safety. The objective of this sodium research apparatus is to combine the best features of each instrument commonly associated with sodium research loops in a cost effective manner while still obtaining high fidelity data. Furthermore, an innovative design of the loop maximizes the volume of available research space inside of the glovebox by mounting the diagnostic loop adjacent to the glovebox.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

Experimental Capability for Preparation and Purification of Molten Salts to Support Advanced Reactor Concepts, Nuclear Hybrid Energy Systems and Dynamic Grid Energy Storage Concepts

High-temperature multi-fluid, multi-loop test facility to support thermal hydraulic, materials, and thermal energy storage research for nuclear and nuclear-hybrid applications is being developed at Idaho National Laboratory (INL). In its initial configuration, the facility will include a high-temperature helium loop, a liquid salt loop, and a hot water/steam loop. The three loops will be thermally coupled through an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX). Based on its relevance to advanced reactor systems, the new facility has been named the Advanced Reactor Technology Integral System Test (ARTIST) facility. The main objectives to be addressed with this facility include the characterization and performance evaluation of candidate compact heat exchangers at prototypical operating conditions, flow, and heat transfer issues related to core thermal hydraulics in advanced helium-cooled and salt-cooled reactors, and evaluation of corrosion behavior of new cladding materials and accident-tolerant fuels for light water reactors at prototypical conditions. Fluoride salt coolants are eutectic binary or tertiary mixtures of fluoride salts with melting points in the range of 320 to 500 deg. C. Fluoride high temperature reactors have reactor outlet temperatures of 600 deg. C or higher for high-efficiency power generation or process heat applications. To address research needs related to salt coolants experimental capability has been added to study thermodynamic properties such as melting point temperature, heat capacity, and thermal conductivity.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Sorption‐Enhanced Mixed Matrix Membranes with Facilitated Hydrogen Transport for Hydrogen Purification and CO 2 Capture

Abstract Mixed matrix membranes (MMMs) comprising size‐sieving fillers dispersed in polymers exhibit diffusivity selectivity and may surpass the upper bound for gas separation, but their performance is limited by defects at the polymer/filler interface. Herein, a fundamentally different approach employing a highly sorptive filler that is inherently less sensitive to interfacial defects is reported. Palladium nanoparticles with extremely high H 2 sorption are dispersed in polybenzimidazole at loadings near the percolation threshold, which increases both H 2 permeability and H 2 /CO 2 selectivity. Performance of these MMMs surpasses the state‐of‐the‐art upper bound for H 2 /CO 2 separation with polymer‐based membranes. The success of these sorption‐enhanced MMMs for H 2 /CO 2 separation may launch a new research paradigm that taps the enormous knowledge of affinities between gases and nanomaterials to design MMMs for a wide variety of gas separations.

Zhu, Lingxiang↗
DOE OSTI2015

Purification and Characterization of Protein Nanotubes Assembled from a Single Bacterial Microcompartment Shell Subunit

Bacterial microcompartments (BMCs) are apparently icosahedral proteinaceous organelles that are bioinformatically identified in an increasing number of bacterial species. BMCs are delimited by a protein shell composed predominantly of hexameric (BMC-H) subunits that tile into the facets of the BMC shell. Here we report a new biomaterial composed of the single BMC-H protein encoded in the BMC locus of Mycobacterium smegmatis; the function of this type of BMC is unknown. When expressed in Escherichia coli, this BMC-H protein, RmmH, self-assembles into nanotubes, densely packed in the cytoplasmic space. These are the first BMC nanotubes to be purified from cells intact and characterized. Here, we also show formation of the nanotubes initiated from free RmmH hexamers in vitro. Based on the dimensions of the nanotubes and modeling of the RmmH hexamer, we propose two possible structural models. BMC nanotubes offer a new spatial architecture both in vivo and in vitro, composed of a single protein that may be genetically or chemically modified and for use as tubular scaffolding.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Amino‐Functionalised Hybrid Ultramicroporous Materials that Enable Single‐Step Ethylene Purification from a Ternary Mixture

Abstract Pyrazine‐linked hybrid ultramicroporous (pore size <7 Å) materials (HUMs) offer benchmark performance for trace carbon capture thanks to strong selectivity for CO 2 over small gas molecules, including light hydrocarbons. That the prototypal pyrazine‐linked HUMs are amenable to crystal engineering has enabled second generation HUMs to supersede the performance of the parent HUM, SIFSIX‐3‐Zn , mainly through substitution of the metal and/or the inorganic pillar. Herein, we report that two isostructural aminopyrazine‐linked HUMs, MFSIX‐17‐Ni (17=aminopyrazine; M=Si, Ti), which we had anticipated would offer even stronger affinity for CO 2 than their pyrazine analogs, unexpectedly exhibit reduced CO 2 affinity but enhanced C 2 H 2 affinity. MFSIX‐17‐Ni are consequently the first physisorbents that enable single‐step production of polymer‐grade ethylene (>99.95 % for SIFSIX‐17‐Ni ) from a ternary equimolar mixture of ethylene, acetylene and CO 2 thanks to coadsorption of the latter two gases. We attribute this performance to the very different binding sites in MFSIX‐17‐Ni versus SIFSIX‐3‐Zn .

Mukherjee, Soumya↗
DOE OSTI2020

Improved two–stage protein expression and purification via autoinduction of both autolysis and auto DNA/RNA hydrolysis conferred by phage lysozyme and DNA/RNA endonuclease

We report improved release of recombinant proteins in Escherichia coli, which relies on combined cellular autolysis and DNA/RNA autohydrolysis, conferred by the tightly controlled autoinduction of both phage lysozyme and the nonspecific DNA/RNA endonuclease from Serratia marcescens. Autoinduction occurs in a two–stage process wherein heterologous protein expression and autolysis enzymes are induced upon entry into stationary phase by phosphate depletion. Cytoplasmic lysozyme and periplasmic endonuclease are kept from inducing lysis until membrane integrity is disrupted. After cell harvest, the addition of detergent (0.1% Triton X–100) and a single 30 min freeze–thaw cycle results in >90% release of protein, green fluorescent protein. Here, this cellular lysis is accompanied by complete oligonucleotide hydrolysis. The approach has been validated for shake flask cultures, high–throughput cultivation in microtiter plates, and larger scale stirred–tank bioreactors. This tightly controlled system enables robust growth and resistance to lysis in routine media when cells are propagated and autolysis/hydrolysis genes are only induced upon phosphate depletion

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Lithium purification from aqueous solutions using bioinspired redox-active melanin membranes

The separation of lithium from magnesium ions in salt brines is an important step in producing raw lithium for prospective use in electrochemical storage systems. Liquid–liquid extraction of Mg 2+ ions from Li + ions is challenging because of comparable thermodynamic behavior in aqueous solutions. Removing Mg 2+ ions from brines using consumable ion-exchange membranes is also a challenging prospect due to poor chemical selectivity and compromised sustainability. In this work, we propose the use of redox-active catechols in the form of melanin pigments for selective removal of Mg 2+ ions from aqueous solutions. Synthetic melanin films are oxidatively polymerized on stainless steel meshes from aqueous solutions of dopamine precursors to create electrochemically functionalized polydopamine membranes. The binding selectivity of redox-active catechol-bearing polydopamine melanin for Mg 2+ ions in aqueous solutions was measured as a function of electrochemical cycling. The binding kinetics of Mg 2+ ions to polydopamine pigments was measured. Mg 2+ ions binding selectivity to polydopamine in mixed aqueous solutions containing both Li + and Mg 2+ ions were also measured. Additionally, the equilibrium binding concentrations of Mg 2+ ions to polydopamine were achieved very rapidly (<1 min). Finallym, redox-active polydopamine membranes therefore show promise as functional materials for the separation of Mg 2+ and Li + ions in aqueous solutions.

25 ENERGY STORAGE↗
DOE OSTI2019

Cloning, Purification, and Characterization of Recombinant Thermostable β-Xylanase Tnap-0700 from Thermotoga naphthophila

The gene of a β-xylanase (Tnap-0700) was cloned from a hyperthermophilic Thermotoga naphthophila strain ATCC BAA-489 and expressed in Escherichia coli BL21 (DE3) via pET-21a (+) as an expression vector. The growth steps were upgraded for highest β-xylanase expression via several factors, for example, IPTG concentration, time of induction, pH, and temperature. The pH and temperature optima for the extreme expression of β-xylanase were 7.0 pH and 37 °C, correspondingly. Recombinant enzyme purified by heat treatment process, then later by immobilized metal ion affinity chromatography. Molecular mass of the purified β-xylanase was 38 kDa observed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable at room temperature for 30 days. It exhibited high stability over wide series of temperature 50–90 °C and pH 4.0–9.0 upon the addition of 1 mM Ca{sup +2} and reduced in the existence of Cu{sup +2} and EDTA. The addition of about 10–30% different organic solvents have no considerable effect on enzyme. However, SDSF and urea acting as an inhibitor leads to decrease in the enzyme activity. The β-xylanase enzyme was active to hydrolyze xylan from beechwood forming xylose. Thermostable β-xylanase causes the breakdown of complex carbohydrates into monosaccharide components. This thermostable β-xylanase revealed remarkable properties, which make it an encouraging candidate for various industrial applications especially in the alteration of renewable biomaterials into ethanol production, and biofuels from lignocellulosics has acknowledged much devotion subsequently in the last decade.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

A review on bacteria-derived antioxidant metabolites: their production, purification, characterization, potential applications, and limitations

Abstract Antioxidants are organic molecules that scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS), thereby maintaining cellular redox balance in living organisms. The human body synthesizes endogenous antioxidants, whereas humans obtain exogenous antioxidants from other organisms such as plants, animals, fungi, and bacteria. This review primarily focuses on the antioxidant potential of natural metabolites and extracts from five major bacterial phyla, including the well-studiedActinobacteriaandCyanobacteria, as well as less-studiedBacteroides,Firmicutes, andProteobacteria.The literature survey revealed that the metabolites and the extracts with antioxidant activity can be obtained from bacterial cells and their culture supernatants. The metabolites with antioxidant activity include pigments, phycobiliproteins, polysaccharides, mycosporins-like amino acids, peptides, phenolic compounds, and alkaloids. Both metabolites and extracts demonstrate in vitro antioxidant capacity through radical-scavenging, metal-reducing, and metal-chelating activity assays. In in vivo models, they can scavenge ROS and RNS directly and/or indirectly eliminate them by enhancing the activities of antioxidant enzymes, such as catalase, superoxide dismutase, and glutathione peroxidase. Due to their antioxidant activities, they may find applications in the cosmetic industry as anti-aging agents for the skin and in medicine as drugs or supplements for combating oxidative stress-related disorders, such as neurodegenerative diseases and diabetes. The literature survey also elucidated that some metabolites and extracts with antioxidant activity also exhibited strong antimicrobial properties. Therefore, we consider that they may have future applications in the treatment of infectious diseases, the preparation of pathogen-free healthy foods, and the extension of food shelf life.

Pharmacology & Pharmacy↗