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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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Determine a feasible method to remove protective plastic coating from steel after CO 2 cutting that will enable high through put and reduce man hours spent on removing plastic by hand. Company is open to any and all ideas.
A variety of recent work has expanded capabilities in LAMÉ with respect to anisotropic and modular plasticity model. In this context, modular refers to a flexible framework and consistent implementation such that different hardening functional forms may all be incorporated into the same material model implementation rather than needing a new model for each description. However, such work has been focused on three-dimensional formulations and limited attention has been paid to structural formulations; i.e. for use with beam or shell elements. As a first step to bringing some of these recent advances towards structural elements, modular isotropic hardening capabilities will be added to the J2 von Mises plane-stress plasticity formulation of Simo and Taylor. To accomplish this effort, in Section 2 and 3 the theory and numerical formulation of the model are given. Specific functional forms of the hardening and example syntax to use them are then presented in Section 4 while verification exercises are documented in Section 5. Finally, some concluding thoughts about future work are given in Section 6.
Single use conventional plastics are extremely durable, rarely recycled and a source of pollution in nature. We help discover new biodegradable plastics to replace the highly polluting ones!
This study investigated the correlation between severe plastic deformation and microstructural evolution, along with the corresponding response in the thermoelectric performance. Specifically, severe plastic deformation introduced into intrinsically brittle thermoelectric materials like Bi 2 Te 3 - x Se x leads to microstructural changes ranging from nano- to micro- scales, including phase transformation, phase segregation, and stacking faults. The resultant residual strain and lattice defects in the Bi 2 Te 3-x Se x materials led to engineering of electronic bands, which increases the effective mass of electrons while controlling their concentration, thereby enhancing the power factor.
Co-gasification of plastics mixture with biomass has shown synergistic effects in Microwave (MW) reactor resulting in higher H2-rich syngas yield and reduced char/tar. This study investigates a microwave-assisted catalytic gasification of variable feedstock such as various biomass blended with mixed plastics waste using Fe-based catalyst to produce H2 rich syngas as a primary product.
Final report for Plastic Additive, Sorbent-Coated, Thermally Integrated Contactor for CO2 Capture (PLASTIC4CO2) DE-FE-0032132. The goal of the work was to investigate at a technology readiness level of 3 (TRL 3), the proof of concept of an additively printed plastic 2-channel heat exchanger/sorbent contactor system to achieve a 15% lower levelized cost of electricity (LCOE) than a baseline liquid phase amine adsorber system for 90% and 95% capture of CO 2 from both a 7F02 2x1CC and 7HA02 2x1CC natural gas turbines.
The onset of plasticity can be assessed and related to ensuing plastic deformation up to the structural instability using one constitutive relationship that incorporates both behaviors of rapid work hardening (Stage 3) and the asymptotic leveling of stress (Stage 4). Results are presented wherein the work hardening variation of Stages 3 and 4 are found to be dependent through a constitutive relationship and useful in a Hall-Petch formulation of strength.
“Candidatus Marithrix” is a recently described lineage within the group of large sulfur bacteria (Beggiatoaceae, Gammaproteobacteria). This genus of bacteria comprises vacuolated, attached-living filaments that inhabit the sediment surface around vent and seep sites in the marine environment. A single filament is ca. 100 µm in diameter, several millimeters long, and consists of hundreds of clonal cells, which are considered highly polyploid. Based on these characteristics, “Candidatus Marithrix” was used as a model organism for the assessment of genomic plasticity along segments of a single filament using next generation sequencing to possibly identify hotspots of microevolution. Using six consecutive segments of a single filament sampled from a mud volcano in the Gulf of Mexico, we recovered ca. 90% of the “Candidatus Marithrix” genome in each segment. There was a high level of genome conservation along the filament with average nucleotide identities between 99.98 and 100%. Different approaches to assemble all reads into a complete consensus genome could not fill the gaps. Each of the six segment datasets encoded merely a few hundred unique nucleotides and 5 or less unique genes—the residual content was redundant in all datasets. Besides the overall high genomic identity, we identified a similar number of single nucleotide polymorphisms (SNPs) between the clonal segments, which are comparable to numbers reported for other clonal organisms. An increase of SNPs with greater distance of filament segments was not observed. The polyploidy of the cells was apparent when analyzing the heterogeneity of reads within a segment. Here, a strong increase in single nucleotide variants, or “intrasegmental sequence heterogeneity” (ISH) events, was observed. These sites may represent hotspots for genome plasticity, and possibly microevolution, since two thirds of these variants were not co-localized across the genome copies of the multicellular filament.
In this study, the complex relationship between deformation history and residual stresses in a magnesium-to-aluminum self-pierce riveted (SPR) joint is elucidated using numerical and experimental approaches. Non-linear finite element (FE) simulations incorporating strain rate and temperature effects were performed to model the deformation in the SPR process. In order to accurately capture the deformation, a stress triaxiality-based damage material model was employed to capture the sheet piercing from the rivet. Strong visual comparison between the physical cross-section of the SPR joint and the simulation was achieved. To aid in understanding of the role of deformation in the riveting process and to validate the modeling approach, several experimental measurements were conducted. To quantify the plastic deformation from the piercing of the rivet, micro hardness mapping was performed on a cross-section of the SPR joint. The FE model showed very strong correlation to the experimental hardness mapping results suggesting the nonlinear model captured the plastic deformation with high accuracy. To measure the elastic residual stresses in the SPR joint, neutron and x-ray diffraction mapping techniques were conducted and in general, the FE model correlated well to the trends and magnitudes of the elastic stresses. While some error occurred in between the model and the neutron and x-ray diffraction results, the numerical approach developed in this study shows potential as a tool for understanding SPR behavior as well as optimizing the process parameters.
The Agile BioFoundry (ABF) is a consortium of national laboratories dedicated to accelerating biomanufacturing and enabling the bioeconomy. The ABF operates a flexible biotechnology platform that can adjust to the needs of numerous government, academic, and industrial partners, thus enabling them to rapidly develop and optimize the production of a wide range of bioproducts. In this project, the ABF partnered with Birch Biosciences, Inc. to use ABF technology to assist in the development of high-performance enzymes that enable circular, sustainable recycling of poly(ethylene terephthalate) (PET) plastics. A primary goal of this project is to enable cost-effective, high yield, sustainable recycling of PET plastic packaging products.
Munc13–1 acts as a master regulator of neurotransmitter release, mediating docking-priming of synaptic vesicles and diverse presynaptic plasticity processes. It is unclear how the functions of the multiple domains of Munc13–1 are coordinated. The crystal structure of a Munc13–1 fragment including its C1, C2B and MUN domains (C1C2BMUN) reveals a 19.5 nm-long multi-helical structure with the C1 and C2B domains packed at one end. The similar orientations of the respective diacyglycerol- and Ca2+-binding sites of the C1 and C2B domains suggest that the two domains cooperate in plasma-membrane binding and that activation of Munc13–1 by Ca2+ and diacylglycerol during short-term presynaptic plasticity are closely interrelated. Electrophysiological experiments in mouse neurons support the functional importance of the domain interfaces observed in C1C2BMUN. The structure imposes key constraints for models of neurotransmitter release and suggests that Munc13–1 bridges the vesicle and plasma membranes from the periphery of the membrane-membrane interface.
CARM1 is a cancer-relevant protein arginine methyltransferase that regulates many aspects of transcription. Its pharmacological inhibition is a promising anti-cancer strategy. Here SKI-73 (6a in this work) is presented as a CARM1 chemical probe with pro-drug properties. SKI-73 (6a) can rapidly penetrate cell membranes and then be processed into active inhibitors, which are retained intracellularly with 10-fold enrichment for several days. These compounds were characterized for their potency, selectivity, modes of action, and on-target engagement. SKI-73 (6a) recapitulates the effect of CARM1 knockout against breast cancer cell invasion. Single-cell RNA-seq analysis revealed that the SKI-73(6a)-associated reduction of invasiveness acts by altering epigenetic plasticity and suppressing the invasion-prone subpopulation. Interestingly, SKI-73 (6a) and CARM1 knockout alter the epigenetic plasticity with remarkable difference, suggesting distinct modes of action for small-molecule and genetic perturbations. We therefore discovered a CARM1-addiction mechanism of cancer metastasis and developed a chemical probe to target this process.
In a variety of species and behavioral contexts, learning and memory formation recruits two neural systems, with initial plasticity in one system being consolidated into the other over time. Moreover, consolidation is known to be selective; that is, some experiences are more likely to be consolidated into long-term memory than others. Here, we propose and analyze a model that captures common computational principles underlying such phenomena. The key component of this model is a mechanism by which a long-term learning and memory system prioritizes the storage of synaptic changes that are consistent with prior updates to the short-term system. This mechanism, which we refer to as recall-gated consolidation, has the effect of shielding long-term memory from spurious synaptic changes, enabling it to focus on reliable signals in the environment. We describe neural circuit implementations of this model for different types of learning problems, including supervised learning, reinforcement learning, and autoassociative memory storage. These implementations involve synaptic plasticity rules modulated by factors such as prediction accuracy, decision confidence, or familiarity. We then develop an analytical theory of the learning and memory performance of the model, in comparison to alternatives relying only on synapse-local consolidation mechanisms. We find that recall-gated consolidation provides significant advantages, substantially amplifying the signal-to-noise ratio with which memories can be stored in noisy environments. We show that recall-gated consolidation gives rise to a number of phenomena that are present in behavioral learning paradigms, including spaced learning effects, task-dependent rates of consolidation, and differing neural representations in short- and long-term pathways.
In a variety of species and behavioral contexts, learning and memory formation recruits two neural systems, with initial plasticity in one system being consolidated into the other over time. Moreover, consolidation is known to be selective; that is, some experiences are more likely to be consolidated into long-term memory than others. Here, we propose and analyze a model that captures common computational principles underlying such phenomena. The key component of this model is a mechanism by which a long-term learning and memory system prioritizes the storage of synaptic changes that are consistent with prior updates to the short-term system. This mechanism, which we refer to as recall-gated consolidation, has the effect of shielding long-term memory from spurious synaptic changes, enabling it to focus on reliable signals in the environment. We describe neural circuit implementations of this model for different types of learning problems, including supervised learning, reinforcement learning, and autoassociative memory storage. These implementations involve synaptic plasticity rules modulated by factors such as prediction accuracy, decision confidence, or familiarity. We then develop an analytical theory of the learning and memory performance of the model, in comparison to alternatives relying only on synapse-local consolidation mechanisms. We find that recall-gated consolidation provides significant advantages, substantially amplifying the signal-to-noise ratio with which memories can be stored in noisy environments. We show that recall-gated consolidation gives rise to a number of phenomena that are present in behavioral learning paradigms, including spaced learning effects, task-dependent rates of consolidation, and differing neural representations in short- and long-term pathways.
Waveguide windows made with polystyrene preformed plastic and sealed with foamed-in-place plastic are useful in any microwave waveguide system using cryogenic cooling.
Microwave interferometer system controls the cutting of plastic materials to a prescribed depth. The interferometer is mounted on a carriage with a spindle and cutting tool. A cross slide, mounted on the carriage, allows the interferometer and cutter to move toward or away from the plastic workpiece.
Electrically conductive plastics fabrication and applications limitations, discussing plastic matrix materials loaded with various conductive fillers
New plastics technology bred out of the space program has moved steadily into the U.S. economy in a variety of organized and deliberate ways. Examples are presented of the transfer of plastics know-how into the plants and eventually the products of American business.