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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 1,423 records · Page 79
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Quantitative characterization of collagen in the fibrotic capsule surrounding implanted polymeric microparticles through second harmonic generation imaging

The collagenous capsule formed around an implant will ultimately determine the nature of its in vivo fate. To provide a better understanding of how surface modifications can alter the collagen orientation and composition in the fibrotic capsule, we used second harmonic generation (SHG) microscopy to evaluate collagen organization and structure generated in mice subcutaneously injected with chemically functionalized polystyrene particles. SHG is sensitive to the orientation of a molecule, making it a powerful tool for measuring the alignment of collagen fibers. Additionally, SHG arises from the second order susceptibility of the interrogated molecule in response to the electric field. Variation in these tensor components distinguishes different molecular sources of SHG, providing collagen type specificity. Here, we demonstrated the ability of SHG to differentiate collagen type I and type III quantitatively and used this method to examine fibrous capsules of implanted polystyrene particles. Data presented in this work shows a wide range of collagen fiber orientations and collagen compositions in response to surface functionalized polystyrene particles. Dimethylamino functionalized particles were able to form a thin collagenous matrix resembling healthy skin. These findings have the potential to improve the fundamental understanding of how material properties influence collagen organization and composition quantitatively.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

In-situ polymerized and crosslinked electrolytes with interchangeable Li/Na transport for battery applications

The next generation of batteries requires electrolytes with high conductivity, mechanical stability, good adhesion with electrodes, wide electrochemical windows, and scalability. The present study introduces a concept of doped quasi single-ion conducting copolymers based on methacrylate-(trifluoromethanesulfonyl)imide (TFSI) and vinyl ethylene carbonate which at room temperature are mechanically robust and display ionic conductivities of ~0.1 mS/cm. These electrolytes can be polymerized/crosslinked in-situ, making them easily implementable in current battery manufacturing technologies. They also allow for switching between Li + and Na + transport using simple chemistry procedures. To demonstrate their potential for battery applications, the newly developed Li conductors have been tested in symmetric cells, exhibiting overall impedance below 350 Ohm and plating/stripping stability up to 1 mA/cm 2 . Moreover, lithium metal batteries incorporating this electrolyte and high-voltage Lithium Nickel Manganese Cobalt Oxide (NMC) cathodes show good capacity retention (~79%) during charging and discharging for 80 cycles at C/10 rate and a Coulombic efficiency close to 100% in the entire measurement range. The compositional, mechanical and electrochemical versatility of these electrolytes opens new venues for the design of polymer-based batteries capable of fast charging and extended cycle life, aligning with the current global green energy storage strategies.

Polymer electrolytes↗
DOE OSTI2010

Development of Nanofiller-Modulated Polymeric Oxygen Enrichment Membranes for Reduction of Nitrogen Oxides in Coal Combustion

North Carolina A&T State University in Greensboro, North Carolina, has undertaken this project to develop the knowledge and the material to improve the oxygen-enrichment polymer membrane, in order to provide high-grade oxygen-enriched streams for coal combustion and gasification applications. Both experimental and theoretical approaches were used in this project. The membranes evaluated thus far include single-walled carbon nano-tube, nano-fumed silica polydimethylsiloxane (PDMS), and zeolite-modulated polyimide membranes. To document the nanofiller-modulated polymer, molecular dynamics simulations have been conducted to calculate the theoretical oxygen molecular diffusion coefficient and nitrogen molecular coefficient inside single-walled carbon nano-tube PDMS membranes, in order to predict the effect of the nano-tubes on the gas-separation permeability. The team has performed permeation and diffusion experiments using polymers with nano-silica particles, nano-tubes, and zeolites as fillers; studied the influence of nano-fillers on the self diffusion, free volume, glass transition, oxygen diffusion and solubility, and perm-selectivity of oxygen in polymer membranes; developed molecular models of single-walled carbon nano-tube and nano-fumed silica PDMS membranes, and zeolites-modulated polyimide membranes. This project partially supported three graduate students (two finished degrees and one transferred to other institution). This project has resulted in two journal publications and additional publications will be prepared in the near future.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2012

The Arabidopsis Wave Complex: Mechanisms of Localized Actin Polymerization and Growth

Plant cells are complex energy storage systems that convert solar radiation to reduced carbon. The chemical form of the storage molecule varies depending on the species and cell type, but sucrose, fructans, starch, or lipids are common examples. The compartmentation of metabolic activities within specific organelles and the intracellular transport and fusion of specialized compartments are key components to energy storage. In the context of cellular engineering, is critical to gain a deep understanding of how metabolic activities are integrated with the organelles and inter-organelle transport. In plant cells, actin filaments are highly dynamic structural elements that define the overall architecture of the cytoplasm and organelle transport activities in the cell. Stable actin bundles are critical architectural elements that position organelles and serves as tracks for motor-dependent organelle trafficking. Subsets of dynamic actin do work by generating membrane tension or by driving organelle fusion, and organelle motility. However, in plants we know very little about when and how particular actin filament arrays are generated and their cellular function. The lack of knowledge impedes efforts to use protein assemblies to dictate the trafficking and growth behaviors of cells. The objective of this project was to discover the protein complexes and control mechanisms that determine the location of actin filament roadways in plant cells. Our work provided the first molecular description of protein complexes that are converted from inactive complexes to active actin filament nucleators in the cell. These discoveries provided a conceptual framework to control to roadways in plant cells that determine the location and delivery of plant metabolites and storage molecules that are relevant to the bioenergy economy.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2013

Development of Advanced Polymeric Reflector for CSP Applications - Final Report

This project attempted to deposit extremely thick and dense protective barrier onto a mirror film stack with a PET substrate. The target thickness was very high for thin film products; particularly since large areas and long production lengths of film are needed to make the final product economic. The technical investigations in this project centered on maintaining a quality barrier (i.e. dense film) while evaporating alumina with a high deposition rate onto a low cost PET substrate. The project found that the proposed configuration, particularly direct ion bombardment, provides too narrow a solution space to effectively and economically produce the ASRM attempted. The initial project goals were met when depositing on a limited width and at a modest rate. However, expanding to wide deposition at aggressive deposition rates did not produce consistent film quality. Economic viability drives the process to maximize deposition rate. The current system configuration has a limiting upper rate threshold that does not appear economically viable. For future work, alternate approaches seem needed to address the challenges encountered in the scale-up phase of this project.

14 SOLAR ENERGY↗
DOE OSTI2014

Early career: Templating of liquid crystal microstructures by reversible addition-fragmentation chain transfer polymerization

This research has shown that the microstructure of self-assembled copolymers can be decoupled from the polymer chemistry. The simplest polymer architecture, linear block copolymers, is valuable for a broad range of applications, including adhesives and coatings, medical devices, electronics and energy storage, because these block copolymers reproducibly self-assemble into microphase separated nanoscale domains. Unfortunately, the self-assembled microstructure is tuned by polymer composition, thus limiting the potential to simultaneously optimize chemical, mechanical, and transport properties for desired applications. To this end, much work was been put into manipulating block copolymer self-assembly independently of polymer composition. These efforts have included the use of additives or solvents to alter polymer chain conformation, the addition of a third monomer to produce ABC triblock terpolymers, architectures with mixed blocks, such as tapered/gradient polymers, and the synthesis of other nonlinear molecular architectures. This work has shown that the microstructures formed by linear ABC terpolymers can be altered by controlling the architecture of the polymer molecules at a constant monomer composition, so that the microstructure is tuned independently from the chemical properties.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Nanostructured polymeric materials for hydrogen storage

The objective of this project is to develop a new class of hydrogen storage adsorbent, nanostructured porous organic polymers (POPs), through collaboration between Argonne National Laboratory and The University of Chicago. POPs have excellent thermal stability and tolerance to gas contaminants such as moisture. They also have low skeleton density and high intrinsic porosity via covalent bonds, capable of maintaining specific surface area (SSA) during high pressure pelletizing for better volumetric density. Furthermore, they can be produced at a commercial scale with the existing industrial infrastructure. The team’s approach focused on improving hydrogen uptake capacity and the heat of adsorption by enhancing SSA, porosity control, and framework-adsorbate interactions through rational design and synthesis at the molecular level. The design principles aim at improving the following attributes of the polymers: (a) high SSA to provide sufficient interface with H2; (b) narrow pore diameter to enhance van der Waals interactions in the confined space; and (c) “metallic” features, either through π- conjugation or metal doping, to promote electronic orbital interactions with hydrogen.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Modeling of ESD Events from Polymeric Surfaces

Transient electrostatic discharge (ESD) events are studied to assemble a predictive model of discharge from polymer surfaces. An analog circuit simulation is produced and its response is compared to various literature sources to explore its capabilities and limitations. Results suggest that polymer ESD events can be predicted to within an order of magnitude. These results compare well to empirical findings from other sources having similar reproducibility.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Energy-Efficient Purification of Bio-Fuels and Bio-Chemicals Using a Novel Advanced Polymeric Membrane System: CRADA Final Report

The team collaborated to develop, demonstrate and move toward the commercialization of a pervaporation membrane system, which reduces the energy required for product isolation from dilute fermentation broths. Avoiding the energy consumption associated with the latent heat of vaporization for water was the key benefit. Essentially, this work isolated high boilers from dilute feeds without evaporating water. These activities lead to the development, fabrication, and demonstration of proprietary, advanced polymer membrane cartridges that dramatically reduce the cost of bio-chemical and bio-fuel manufacture.

09 BIOMASS FUELS↗
DOE OSTI2018

Methanotroph Immobilization in Polymeric Bioreactors to Increase Mass Transfer

Methane, a greenhouse gas, is produced naturally by volcanoes, bacteria, and wildfires. Yet, human activities such as landfills and rice patty fields have increased methane production at an alarming rate. The ability to convert methane to useful products without the use of expensive metal catalysts or elevated reaction conditions is highly sought-after. One such way is using methanotrophs, which naturally consume methane, to produce desired products. In this work, we strive to expedite biology and produce muconic acid via bioengineered methanotrophic bacteria, which can be used to synthesize adipic acid — a precursor to nylon. Positive outcomes have been observed previously by immobilizing non-bioengineered methanotroph strains in a hydrogel. Here, the hydrogel was embedded in polymer scaffolds to aid in mass transfer through the hydrogel. A silicone scaffold was chosen due to its gas permeability, biocompatibility, ease of loading, and chemical inertness.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Physics-Based Probabilistic Model of the Effects of Ionizing Radiation on Polymeric Insulators of Electric Cables used in Nuclear Power Plants

This report describes the results of a 3-year project aimed at developing a probabilistic predictive model of degradation of insulation of cables installed in nuclear power plants where heat and radiation are two major environmental stressors. The developed models have been developed based on exploring fundamental physical and chemical processes involved and validated by experimental data from open literature and data collected from experiments conducted as part of this study. The report comprises of two parts: Volume I and Volume II. In Volume I, degradation of three most widely-used insulation materials, cross-linked polyethylene (XLPE or PEX), ethylene propylene rubber (EPR), and silicone rubber (SIR) are discussed. Based on the identified degradation mechanisms and kinetics of the cable insulation, physics-based models have been proposed to quantitatively define and predict the degree of the degradation for functional failures of concern. Various sets of experimental data from the literature were used to help understand the phenomenon involved and to validate the models developed. Further validations were performed with data collected from experiments conducted as part of the research project. Methods and results of the experimental work are detailed in Volume II. These experimental results were found to be consistent with data reported in the literature and support the proposed models. The models developed here can probabilistically predict the lifetime of the cable insulation used in nuclear power plants.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2016

Modeling Shock-Driven Reaction in Low-Density Non-energetic polymeric materials

Shock experiments on low density polyurethane foams reveal evidence of reaction at low impact pressures. However, these reaction thresholds are not evident over the low pressures reported for historical Hugoniot data of highly distended polyurethane at densities below 0.1 g/cc. To fill this gap, impact data for PMDI foam with a density of 0.087 g/cc were acquired for model validation. An equation of state (EOS) was developed to predict the shock response of these highly distended materials over the full range of impact conditions representing compaction of the inert material, low-pressure decomposition, and compression of the reaction products. A tabular SESAME EOS of the reaction products was generated using the JCZS database in the TIGER equilibrium code. In particular, the Arrhenius Burn EOS, a two-state model which transitions from an unreacted to a reacted state using Arrhenius kinetics, as implemented in the shock physics code CTH, was modified to include a statistical distribution of states. Hence, a single EOS is presented that predicts the onset to reaction due to shock loading in PMDI-based polyurethane foams. This methodology was also used to predict the anomalous compaction of PMDI foams over published data sets from 0.087 to 0.87 g/cc, and solid Polyurethane at a theoretical maximum density (TMD) of 1.264 g/cc. Likewise, similar modeling techniques were used to predict the performance of SX-358 foam, an RTV-based stress cushion material at a nominal density of 0.41 g/cc, and the matrix material, with properties similar to Sylgard, at 1.1 g/cc. At the start of this study, data were only available at a single impact condition below the threshold for reaction; hence, the decomposition of this material at higher pressures was revealed as a significant finding of this work. The decomposition of SX-358 at higher impact pressures to product species including solid, liquid, and gaseous molecules was estimated with thermochemical equilibrium calculations using TIGER. with thermochemical equilibrium calculations using TIGER. This modeling approach, developed for PMDI foam, was shown to predict gas gun data, acquired as part of this study, up to pressures of 14 GPa. Furthermore, additional phase transitions were predicted in the product species under shock compression. To date, this study is the first known to the authors that demonstrates and successfully predicts the decomposition of these low-density polymer-based foams using a single model applicable to a broad range of impact loading conditions.

36 MATERIALS SCIENCE↗