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DOE OSTI2024

Tuning Fabrication Factors for Reduced Graphene Oxide Forward Osmosis Membranes

Forward osmosis (FO) may serve as a near-zero energy approach for wastewater management and selective chemical enrichment with an appropriate FO membrane. There is a need for novel FO membranes with better physical stability, chemical compatibility, and enhanced reverse flux selectivity. In this work, we have systematically studied a variety of factors for fabricating thermally reduced graphene oxide (RGO) FO filtration membranes and have demonstrated that with a comparable water flux, the RGO membranes have an exceptionally large reverse flux selectivity with 1.5 M sodium sulfate draw solution, about 7 times larger than that of cellulose triacetate membranes under the same testing condition. The interlayer spacing of the membranes can be fine-tuned by varying temperatures, so that the free interlayer spacing is less than 0.7 nm after exposure to water. The RGO-based membranes offer a few advantages with high reverse flux selectivity, mechanical robustness with strong adhesion to nylong support membranes without damage after FO tests and tape peel tests, and enhanced chromate and chlorine resistance. Finally, we have further demonstrated that in the FO processes, one can concentrate waste brine while simultaneously harvesting the osmotic energy as electricity, offering potential applications of forward osmosis-based osmotic batteries for powering electronic devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS2006

Formaldehyde Distribution over North America: Implications for Satellite Retrievals of Formaldehyde Columns and Isoprene Emission

Formaldehyde (HCHO) columns measured from space provide constraints on emissions of volatile organic compounds (VOCs). Quantitative interpretation requires characterization of errors in HCHO column retrievals and relating these columns to VOC emissions. Retrieval error is mainly in the air mass factor (AMF) which relates fitted backscattered radiances to vertical columns and requires external information on HCHO, aerosols, and clouds. Here we use aircraft data collected over North America and the Atlantic to determine the local relationships between HCHO columns and VOC emissions, calculate AMFs for HCHO retrievals, assess the errors in deriving AMFs with a chemical transport model (GEOS-Chem), and draw conclusions regarding space-based mapping of VOC emissions. We show that isoprene drives observed HCHO column variability over North America; HCHO column data from space can thus be used effectively as a proxy for isoprene emission. From observed HCHO and isoprene profiles we find an HCHO molar yield from isoprene oxidation of 1.6 +/- 0.5, consistent with current chemical mechanisms. Clouds are the primary error source in the AMF calculation; errors in the HCHO vertical profile and aerosols have comparatively little effect. The mean bias and 1Q uncertainty in the GEOS-Chem AMF calculation increase from <1% and 15% for clear skies to 17% and 24% for half-cloudy scenes. With fitting errors, this gives an overall 1 Q error in HCHO satellite measurements of 25-31%. Retrieval errors, combined with uncertainties in the HCHO yield from isoprene oxidation, result in a 40% (1sigma) error in inferring isoprene emissions from HCHO satellite measurements.

Millet, Dylan B.↗

NASA NTRS1973

Development of a method for fabricating metallic matrix composite shapes by a continuous mechanical process

The continuing efforts in upscaling to produce larger diameter Al/B tubes are described. While the basic methodology remains unchanged, the larger volume of acrylic binder material and its removal by dissolution in toluene had to be performed by dynamic scrubbing. Similarly, the boron and MCF continuous length requirements increased when a 6 foot long by 7 inches wide mat was needed. These modifications and associated problems are described fully with schematics. Also included are seven experiments conducted to prepare larger tubes. The thermal profile, drawing speeds, and furnace positions in the draw bench bay are presented along with metallographic evidence of composite cross sections.

Divecha, A. P.↗

DOE OSTI2026

Distribution System Congestion Management - A Survey of Reliable Integration for Aggregated Resources and Microgrids

Rising penetration of consumer-owned Distribution Grid Resources (DGRs), increasingly managed by third party aggregators and enrolled in grid services and wholesale market programs, can create localized congestion in distribution networks. Managing these constraints is challenging due to a persistent coordination and information gap: utilities are accountable for reliability and have network topology and state visibility, while aggregators control the DGR capability needed to relieve congestion. This survey synthesizes congestion management solutions for distribution systems with high DGR penetration, covering both market-based mechanisms (distribution level markets, locational pricing, flexibility auctions) and non-market-based solutions (network reconfiguration, direct DGR control, demand response, curtailment, etc.). The literature is organized across three decision horizons: long term planning, operational planning, and real-time operation. Special attention is devoted to emerging distribution system operator architectures and coordination frameworks spanning transmission system operators, aggregators, and microgrids. Drawing on recent case studies and implementations, we distill best practices, identify key technical and economic barriers, and outline research directions. The evidence points to a shift toward integrated congestion management that combines market signals with technical controls, enabled by improved monitoring, forecasting, and closed loop control capabilities.

Active Distribution Networks (ADN)↗

NASA NTRS1997

An Integrated Product Environment

Mechanical Advantage is a mechanical design decision support system. Unlike our CAD/CAM cousins, Mechanical Advantage addresses true engineering processes, not just the form and fit of geometry. If we look at a traditional engineering environment, we see that an engineer starts with two things - performance goals and design rules. The intent is to have a product perform specific functions and accomplish that within a designated environment. Geometry should be a simple byproduct of that engineering process - not the controller of it. Mechanical Advantage is a performance modeler allowing engineers to consider all these criteria in making their decisions by providing such capabilities as critical parameter analysis, tolerance and sensitivity analysis, math driven Geometry, and automated design optimizations. If you should desire an industry standard solid model, we would produce an ACIS-based solid model. If you should desire an ANSI/ISO standard drawing, we would produce this as well with a virtual push of the button. For more information on this and other Advantage Series products, please contact the author.

Higgins, Chuck↗

NASA NTRS2003

The Statistical Mechanics of Ideal MHD Turbulence

Turbulence is a universal, nonlinear phenomenon found in all energetic fluid and plasma motion. In particular. understanding magneto hydrodynamic (MHD) turbulence and incorporating its effects in the computation and prediction of the flow of ionized gases in space, for example, are great challenges that must be met if such computations and predictions are to be meaningful. Although a general solution to the "problem of turbulence" does not exist in closed form, numerical integrations allow us to explore the phase space of solutions for both ideal and dissipative flows. For homogeneous, incompressible turbulence, Fourier methods are appropriate, and phase space is defined by the Fourier coefficients of the physical fields. In the case of ideal MHD flows, a fairly robust statistical mechanics has been developed, in which the symmetry and ergodic properties of phase space is understood. A discussion of these properties will illuminate our principal discovery: Coherent structure and randomness co-exist in ideal MHD turbulence. For dissipative flows, as opposed to ideal flows, progress beyond the dimensional analysis of Kolmogorov has been difficult. Here, some possible future directions that draw on the ideal results will also be discussed. Our conclusion will be that while ideal turbulence is now well understood, real turbulence still presents great challenges.

Shebalin, John V.↗

DOE OSTI2021

Cytochrome Nanowire XRD

Microbial metabolism plays an important role in the global cycling of carbon, nutrients, and metals. Recent discovery of microorganisms sharing energy using direct electrical connections might represent a prominent strategy by which anaerobic microorganisms interact with the diversity of environments. The purpose of the proposed research is to apply these newly developed principles of electron exchange in microbial communities to the study of biogeochemical cycling in climate and subsurface systems. Previous studies revealed that soil bacteria Geobacter sulfurreducens produce conductive pili nanofilaments that facilitate long-range electron transport to extracellular electron acceptors and other cells. This discovery has already transformed our understanding of the function of microbial communities in diverse environments, making basic contributions to microbial ecology and helping to improve practical applications such as increasing current output of microbial fuel cells and enhancing the conversion of organic waste to methane. Microbial electron exchange via pili may also contribute to methane production in terrestrial environments that are major sources of atmospheric methane. However, the mechanism of electron transport through pili is not well understood. Initial studies have suggested that pili exhibit metallic-like conductivity similar to conducting polymer polyaniline. However, these studies were limited to electrical measurements. X-ray diffraction studies have suggested that aromatic amino acids tyrosine and phenylalanine are closely packed in pili. But these studies used homology modeling to predict the pilus assembly and information about the number of monomers in each pilus assembly unit and their organization are still lacking. The central hypothesis of this proposal is aromatics in pili enable intermolecular electron delocalization due to pi-stacking that can give rise to metallic-like conductivity. By analyzing pili structure using infrared scattering-scanning near field optical microscope (IR s-SNOM) and combining with solution NMR, Focused Ion Beam (FIB and computational capabilities, this work will provide comprehensive understanding of the conduction mechanism from a structure-function perspective. The specific aims are: 1) With infrared scattering scanning near field optical microscope (IR s-SNOM), image the organization and density of pilin monomers and pH-induced conformational changes in a pilus filament. 2) With solution NMR, resolve pH-induced structural changes in the pilin monomer. 3) Using Focused Ion Beam (FIB), draw electrodes on single pili to measure their conductivity. 4) With computational modeling using the NWChem, simulate the effect of environment on the electronic properties of pili as a function of pH. The proposed work will gain the nanoscale insight into the structure of the pili, as the basis for understanding interspecies electrical communications. The improved understanding will be harnessed to accelerate bioenergy production and bioremediation using pili as well as for predictive modeling of carbon cycling in diverse environments to reach the central goals of DOE-BER to develop sustainable energy sources, regulate the contaminants in the subsurface and understand the effects of greenhouse gas emissions on biosphere. The proposed studies will provide design principles for engineering of electrical interactions among these communities by manipulating the amino acid composition of pili. Moreover, these studies will identify the forces that maintain the function of these communities in the face of environmental perturbation. Therefore, these studies will help to address the need "to incorporate process understanding of biogeochemical cycling into a scalable hierarchy of predictive capabilities" specified in EMSL's Science Themes.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS1984

Osseous adaptation to continuous loading of rigid endosseous implants

The effect of loading on etched Ti implants in the femurs of young (3 mo) and adult (6 mo) rabbits is investigated experimentally. The results are presented in photographs, fluorescence and polarization micrographs, radiographs, and drawings and discussed. Implantation is followed by formation of coarse woven bone within 3 d and mature lamellar bone by 6 wks, with nonspecific subperiosteal bony hypertrophy in the young rabbits only. Spring loading at 100 g produces spontaneous spiral-type fractures when applied immediately, but the implants remain rigid when loads are applied after 6-12 wks of healing. The mechanisms of bone formation involved are examined, and the potential of endosseous implants as anchors in orthodontics or dentofacial-orthopedics is confirmed.

Roberts, W. E.↗

NASA NTRS1999

Virtual Build: Low-Tech Simulations Can Be High on IPPD Content

After two years of design, component testing, and parts fabrication, the project team was within months of starting assembly on the first major elements of a new product assembly. Schedules were extremely tight and there was no room for error in the first unit build-up for test. The first draft of the assembly drawing was nearing completion and needed to be approved by key members of the Integrated Product Team (IPT) before release. Only then could the manufacturing planning be finalized and released for assembly to begin. What could we do to improve the quality of our first build effort? How could we minimize all the changes inherent in the first-time build of a complex mechanical system? Why not a dress rehearsal of the build process with all the participating players, hardware, and build documentation? A "virtual build simulation". In an organization employing integrated product teams there is no substitute for clear communication between the various cross-functional members. Despite team collocation, integrated solid modeling, and frequent coordination meetings. elements of the product-process design can still slip through the cracks and show up on the assembly floor. The virtual build exercise was designed to provide one intensive hands-on experience for all members of the design and assembly team in time to make corrections without schedule impact.

Hilscher, Rick↗

DOE OSTI2022

Simulation study of chemo-mechanical impacts of CO 2 injection in morrow b sandstone reservoir

Here, this study investigates the impacts of geomechanical and geochemical changes on carbon storage in a partially depleted oil reservoir, using results from four different coupled simulation models. Models were used to examine the relative importance of storage mechanisms, and how changing reservoir parameters might affect these mechanisms through time. The study uses data from a Morrowan sandstone reservoir in the Farnsworth Unit (FWU), Ochiltree County, Texas which is currently undergoing CO 2 enhanced oil recovery (EOR). Partially depleted oil reservoirs such as the FWU offer attractive carbon utilization and/or storage targets because of existing infrastructure and economic benefits from incremental oil recovery as well as tax credits. However, prediction of storage capacity or long-term fluid migration in these fields can be difficult because of the wide variation in formation fluids and operational histories that may have undergone. CO 2 injection can cause complex geomechanical and geochemical responses in a reservoir as a result of interplay between dynamic changes in pore pressure, reservoir temperature, fluid composition, and interactions between formation fluids, CO 2 , and reservoir rock. Thus, multiple coupled numerical simulation models must be developed and used to more precisely understand what CO 2 storage mechanisms are most significant, as well as the long-term fate of the stored CO 2 . Our study used results from hydrodynamic, coupled hydro-geomechanical, coupled hydro-geochemical, and coupled hydro-geomechanical-geochemical models to examine how changes in geomechanical and geochemical properties can impact the injectivity or storage capacity of CO 2 . Models simulated historical field operations and then forward-modeled a water-alternate-gas (WAG) operation for 20 years, followed by a 1000-year post-injection monitoring. The work demonstrates that in this specific reservoir, geomechanical impacts appear to be more significant than any geochemical processes, which showed minimal impact on reservoir properties. Furthermore, these simulation scenarios corroborated other studies showing more than 90% of CO 2 injected are being stored and will remain stored in the reservoir. The study was able to draw on a rich set of data from this currently operational project for the work. Because the Morrow is a widespread oil-bearing reservoir in the midcontinent of the United States and is fairly typical of many sandstone reservoirs elsewhere, the study has significance beyond the boundaries of our field area.

58 GEOSCIENCES↗

NASA NTRS2020

Evolution of an Atmospheric Kármán Vortex Street From High‐Resolution Satellite Winds: Guadalupe Island Case Study

Vortex streets formed in the stratocumulus‐capped wake of mountainous islands are the atmospheric analogues of the classic Kármán vortex street observed in laboratory ﬂows past bluff bodies. The quantitative analysis of these mesoscale unsteady atmospheric ﬂows has been hampered by the lack of satellite wind retrievals of sufﬁciently high spatial and temporal resolution. Taking advantage of the cutting‐edge Advanced Baseline Imager, we derived kilometer‐scale cloud‐motion winds at 5‐min frequency for a vortex street in the lee of Guadalupe Island imaged by Geostationary Operational Environmental Satellite‐16. Combined with Moderate Resolution Imaging Spectroradiometer data, the geostationary imagery also provided accurate stereo cloud‐top heights. The time series of geostationary winds, supplemented with snapshots of ocean surface winds from the Advanced Scatterometer, allowed us to capture the wake oscillations and measure vortex shedding dynamics. The retrievals revealed a markedly asymmetric vortex decay, with cyclonic eddies having larger peak vorticities than anticyclonic eddies at the same downstream location. Drawing on the vast knowledge accumulated about laboratory bluff body ﬂows, we argue that the asymmetric island wake arises from the combined effects of Earth's rotation and Guadalupe's nonaxisymmetric shape resembling an inclined ﬂat plate at low angle of attack. However, numerical simulations will need to establish whether or not the selective destabilization of the shallow atmospheric anticyclonic eddies is caused by the same mechanisms that destabilize the deep columnar anticyclones of laboratory ﬂows, such as three‐dimensional vertical perturbations due to centrifugal or elliptical instabilities.

Horváth, Á.↗

DOE OSTI2024

Ameliorating the sodium storage performance of hard carbon anode through rational modulation of binder

Hard carbon anodes have emerged as promising candidates for sodium-ion batteries due to their inherent advantages. Nevertheless, the surface imperfections in these materials often culminate in irreversible electrolyte consumption, fostering the development of a heterogeneous and fragile solid electrolyte interface (SEI), thereby compromising the initial Coulombic efficiency (ICE). Here, drawing inspiration from the catalytic potential of C=O (carbonyl) bonds in directing preferential salt reduction, we introduce a novel strategy that leverages the modulation of the binder, a long-term overlooked pivotal components in the electrode process. Specifically, Polymethyl methacrylate (PMMA), abundant in C=O groups, is partially substituted for PVDF, ensuring robust adhesion of the electrode material to the current collector while preserving superior mechanical properties. The accurate combination of two binders with delightful compatibility in the state-of-art electrode process, can promote a uniform formation of the SEI on the hard carbon surface enriched in inorganic components, which can ensure long-term interfacial stability and suppresses excessive solvent decomposition and facilitates Na + transfer at the interface. Consequently, the initial Coulombic efficiency of the hard carbon anode with 70 %PMMA binder achieves 86 %, with prominent cycling stability (88 % capacity retention over 500 cycles) at a high current density of 1.2 A g −1 . When paired with high loading cathodes to assemble the pouch cell, it also demonstrates stable operational scenarios.

25 ENERGY STORAGE↗

DOE OSTI2023

Improved Biofuel Production through Discovery and Engineering of Terpene Metabolism in Switchgrass

Project Objectives - Of the myriad specialized metabolites that plants deploy to adapt to environmental challenges, terpenes form the largest group. In many major crops, unique terpene blends serve as key stress defenses that directly impact plant fitness and yield. In addition, terpenes, such as bisabolene and pinene, are used for producing renewable biofuels. Essential to advancing a broader use of terpenes for biofuel feedstock engineering is a system-wide knowledge of the diverse biosynthetic machinery and defensive potential of often species-specific terpene blends. The proposed project would merge genome-wide enzyme discovery with comparative –omics, protein structural and plant microbiome studies to define the biosynthesis and stress-defensive functions of the switchgrass (Panicum virgatum) terpene network. These insights would be combined with developing and applying non-transgenic genome editing tools to design plants with desirable terpene blends for higher productivity and biofuel production on marginal lands. As a dedicated lignocellulosic feedstock for U.S. biofuel production with high net energy yield, stress tolerance, and available genome resources, switchgrass is well-suited for devising new avenues for biofuel production. Project Description – The diversity of plant terpene defenses is governed by species-specific families of terpene synthase (TPS) and cytochrome P450 monooxygenase (P450) enzymes. Mining of the switchgrass genome (genotype Alamo) identified ~100 TPS and P450 candidate genes, and combinatorial biochemical analysis of synthesized TPSs and P450s revealed more than a dozen enzymes with common and novel activities. In addition, several identified terpene metabolites and the corresponding transcripts were up-regulated in response to abiotic stressors. These findings demonstrate a unique switchgrass terpene network with probable importance to abiotic stress tolerance, thus providing a large chemical portfolio for optimizing crop resistance, yield, and biofuel composition. Leveraging these preliminary data, we propose to generate a genome-wide map of the switchgrass terpene metabolic network through multi-gene co-expression analyses that allow the efficient cross-validation of TPS and P450 functions. Key enzymes would further be applied to structure-function studies via X-ray protein crystallography, homology modeling and site-directed mutagenesis to gain mechanistic insight into the catalytic specificity of switchgrass terpene metabolism and provide gene and amino acid targets for genome editing. In tandem with terpene pathway discovery, system-wide metabolomics, transcriptomics and proteomics studies in switchgrass accessions of contrasting drought tolerance would define the role of switchgrass terpene metabolism in conferring abiotic stress resilience. Metabolic changes would be assessed in a combined approach of targeted (terpenes) and untargeted metabolite profiling using a high-resolution LC-MS/MS approach, differential gene expression analyses through multiplexed Illumina RNA sequencing, and quantitative analysis of high-priority pathway enzymes using multiple reaction monitoring (MRM). Drawing on these insights, knock-down/out mutants of stress-associated pathway nodes would be generated by optimizing transient virus-induced gene silencing (VIGS) and CRISPR/Cas9 systems under control of the Tobacco Rattle Virus (TRV). The resulting mutant lines would then be analyzed for stress susceptibility and the impact on the root microbiome to define gene functions in planta. Knowledge of terpene pathways, enzyme mechanisms and bioactivities would be applied to enhance switchgrass stress resilience and to tailor-make terpene blends for biofuel production. Here, TRV-enabled CRISPR/Cas9 genome editing, including allele-specific knock-out of redundant genes, engineering of enzyme specificity via structure-guided point mutations, and overexpression of terpene genes relevant to stress-protection or biofuel production, would be used to increase metabolic flux toward desired pathways. Broader Impacts - Integrating the system-wide discovery, mechanistic analysis and non-transgenic genome engineering of the switchgrass terpene network aligns the required steps to unlock the chemical potential of this important metabolite class to generate crops that are more resistant to stress and provide advanced biofuel production in light of rising climate pressures as foreseeable challenges for bioenergy crop cultivation. The proposed project would further offer interdisciplinary student training through active involvement in the project and integration of research concepts and outcomes into newly-developed graduate and undergraduate courses on Plant Biotechnology.

09 BIOMASS FUELS↗

NASA NTRS2011

Characterization of Electron Beam Free-Form Fabricated 2219 Aluminum and 316 Stainless Steel

Researchers at NASA Langley Research Center have developed an additive manufacturing technology for ground and future space based applications. The electron beam free form fabrication (EBF3) is a rapid metal fabrication process that utilizes an electron beam gun in a vacuum environment to replicate a CAD drawing of a part. The electron beam gun creates a molten pool on a metal substrate, and translates with respect to the substrate to deposit metal in designated regions through a layer additive process. Prior to demonstration and certification of a final EBF3 part for space flight, it is imperative to conduct a series of materials validation and verification tests on the ground in order to evaluate mechanical and microstructural properties of the EBF3 manufactured parts. Part geometries of EBF3 2219 aluminum and 316 stainless steel specimens were metallographically inspected, and tested for strength, fatigue crack growth, and fracture toughness. Upon comparing the results to conventionally welded material, 2219 aluminum in the as fabricated condition demonstrated a 30% and 16% decrease in fracture toughness and ductility, respectively. The strength properties of the 316 stainless steel material in the as deposited condition were comparable to annealed stainless steel alloys. Future fatigue crack growth tests will integrate various stress ranges and maximum to minimum stress ratios needed to fully characterize EBF3 manufactured specimens.

Ekrami, Yasamin↗

DOE OSTI2023

Computational Theory Applied to Nanostructures (Final Report)

Within the nanoscale, phenomena occur that are characteristic of neither the atomic limit, nor the macroscopic limit. In particular, properties that are intensive at the macroscopic scale become size dependent at the nanoscale. These phenomena can have direct consequence for understanding and characterizing materials used in electronic, optical, and micro-mechanical applications related to energy science and technologies. To capitalize properly on predicting and understanding such phenomena in this nano regime, a deeper understanding of the quantum properties of materials will be required. The objective of our research program was to advance the field in computational modeling, analysis and understanding of materials at the nano scale, both in terms of dimensionality and quantum confinement. We employed a multidisciplinary approach, drawing from physics, materials science, chemical engineering and computer science. This research will provide new knowledge, computational techniques, and provide high-potential links across all these disciplines. Over sixty papers were published during the period in question. Ten of the papers were published in high impact journals such as Nano Letters, Nature Communications and Physical Review Letters.

36 MATERIALS SCIENCE↗

NASA NTRS1978

Owens-Illinois liquid solar collector materials assessment

From the beginning, it was noted that the baseline drawings for the liquid solar collector exhibited a distinct weakness concerning materials specification where elastomers, plastics, and foam insulation materials were utilized. A relatively small effort by a competent design organization would alleviate this deficiency. Based on results obtained from boilout and stagnation tests on the solar simulator, it was concluded that proof testing of the collector tubes prior to use helps to predict their performance for limited service life. Fracture mechanics data are desirable for predicting extended service life and establishing a minimum proof pressure level requirement. The temperature capability of this collector system was increased as the design matured and the coating efficiency improved. This higher temperature demands the use of higher temperature materials at critical locations in the collector.

Nichols, R. L.↗

NASA NTRS2012

Comparison of Ocular Outcomes in Two 14-Day Bed Rest Studies

Reports of astronauts' visual changes have raised concern about ocular health during long-duration spaceflight. Some of these findings include globe flattening with hyperopic shifts, choroidal folds, optic disc edema, retinal nerve fiber layer (RNFL) thickening, and cotton wool spots. While the etiology remains unknown, it is hypothesized that, in predisposed individuals, hypertension in the brain may follow cephalad fluid shifts during spaceflight. This possible mechanism of ocular changes may also apply to analogous cases of idiopathic intracranial hypertension (IIH) or pseudotumor cerebri on Earth patients. Head-down t ilt (HDT) bed rest is a spaceflight analog that induces cephalad fluid shifts. Previous studies of the HDT position demonstrated body fluid shifts associated with changes in intraocular pressure (IOP) but the conditions of bed rest varied among experiments, making it difficult to compare data and draw conclusions. For these reasons, vision evaluation of bed rest subjects was implemented for NASA bed rest studies since 2010, in an attempt to monitor vision health in subjects subjected to bed rest. Vision monitoring is thus currently performed in all NASA-conducted bed rest campaigns

Cromwell, Ronita L.↗

NASA NTRS1984

Reconnection at the earth's magnetopause - Magnetic field observations and flux transfer events

Theoretical models of plasma acceleration by magnetic-field-line reconnection at the earth magnetopause and the high-resolution three-dimensional plasma measurements obtained with the ISEE satellites are compared and illustrated with diagrams, graphs, drawings, and histograms. The history of reconnection theory and the results of early satellite observations are summarized; the thickness of the magnetopause current layer is discussed; problems in analyzing the polarization of current-layer rotation are considered; and the flux-transfer events responsible for periods of patchy reconnection are characterized in detail. The need for further observations and refinements of the theory to explain the initiation of reconnection and identify the mechanism determining whether it is patchy or steady-state is indicated.

Russell, C. T.↗