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DOE OSTI2020

Subtask 1.3 – Integrated Carbon Capture and Storage for North Dakota Ethanol Production

The Energy & Environmental Research Center (EERC), in partnership with Red Trail Energy, LLC (RTE), a North Dakota ethanol producer; the North Dakota Industrial Commission (NDIC) Renewable Energy Program (REP); and the U.S. Department of Energy (DOE), conducted a feasibility and implementation study for a commercial carbon capture and storage (CCS) effort. This subtask provided technical support and developed recommended practices of how small-scale industrial CO2 emitters (<1,000,000 tonnes of CO2 emitted annually) may economically deploy CCS. The 64-million-gallon dry mill RTE ethanol facility, emitting an average 180,000 tonnes of CO2 annually, was the subject of the case study. The positive outcome of this research, which shows technical and economic potential for ethanol–CCS in North Dakota, has resulted in RTE acquiring an approved Permit to Drill on December 2, 2019, for a stratigraphic test well in early 2020, a necessary step toward a North Dakota CO2 Storage Facility Permit (SFP) for the RTE CCS effort. Outcomes include 1) validating the Broom Creek Formation as a regional target for CCS, 2) determining the full carbon life cycle of an industrial fuel production facility with CCS, 3) developing a field implementation plan (FIP) for small-scale CCS, and 4) determining the validity and pathway for using CCS to meet low-carbon fuel (LCF) standards. The technical team included the EERC, RTE, Trimeric Corporation, Schlumberger Carbon Services, and Computer Modelling Group (CMG). Findings from activities conducted November 2016 – May 2020 are summarized as follows. Several key steps have been accomplished toward validating the Broom Creek Formation as a CO2 injection and storage target at the RTE CCS site, including verification of the presence and structure of sandstone layers that may comprise the potential CO2 storage reservoir and the several thousand feet of overlying confining zone. Work included site characterization using existing data, interpretation of seismic data within the study area, and geologic modeling simulation of CO2 injection. Interpreted results estimate 3000 feet of confining zone between the Broom Creek Formation (storage target) and the lowermost underground source of drinking water (e.g., the Fox Hills Formation). The thickness of the Broom Creek injection target varies 230–420 ft within the survey area. Results were used to inform the location of a stratigraphic test well and associated characterization test program. No impediments were identified within the targeted CO2 storage complex that would prevent the project from moving forward. A stratigraphic test well is the next step to validate these results and to acquire remaining data necessary to develop a North Dakota CO2 SFP application. The EERC generated full carbon life cycle estimates for CCS integration with the RTE ethanol facility. Results indicated that an average 40% reduction in CO2 emissions is possible through CCS implementation. Approximately half of the carbon in the overall life cycle for a dry mill ethanol plant is generated through the fermentation process and emitted to the atmosphere; this is the CO2 stream targeted for CCS. The remaining carbon is attributed to corn feedstock farming (diesel, fertilizer), energy for fuel processing (natural gas, electricity), and transportation (diesel) of the fuel product. Life cycle carbon estimates are also affected by the anticipated energy consumption of a potential capture facility, which depend on the type of CO2 product generated. For example, a 30%–40% net CO2 emission reduction is estimated if a liquefied CO2 facility were incorporated compared to a 40%–50% net CO2 reduction if a supercritical “injection-grade” CO2 product is generated; i.e., more energy is required to further refine the CO2 stream, affecting the full carbon life cycle estimates. A CCS FIP was developed and initiated at the RTE CCS site, resulting in the development of several guidance documents: a CO2 Capture Process Design Package, a North Dakota CO2 geologic Storage Permits Template, and a Public Outreach Package for CCS in North Dakota. General FIP components include CO2 capture system, pipeline and well designs; monitoring, verification, and accounting (MVA) plans; geologic characterization and testing programs; and permitting and outreach plans. Vendor bids were also acquired for the CO2 liquefaction facility. Near-surface characterization (groundwater and soil gas sampling) and geologic characterization (seismic survey) were initiated to inform development of a UIC Class VI-compliant MVA plan compliant with a North Dakota CO2 SFP. Designs (well and geologic testing) were completed for a stratigraphic test well compliant with a North Dakota CO2 SFP. In addition, the outreach plan was executed, including community open houses, meetings with city/county/state officials, and development of public materials. Although other entities continued to mature incentive programs in 2019–2020, California and the Internal Revenue Service (IRS) currently provide the most advanced economic opportunities for CCS integrated with fuel production. The California Low-Carbon Fuel Standard (LCFS) adopted a CCS Protocol in January 2019, allowing submittal of a design-based pathway (DBP) application for an approved temporary (not certified) carbon intensity value for a fully engineered facility. An ethanol–CCS DBP application to the California LCFS Program (officially approved February 28, 2020) was developed to show that the RTE CCS effort meets LCFS requirements. The approved DBP provides confidence to advance the project and supports potential investments. Other entities continue to mature incentive programs. The IRS issued guidance in February 2020 that addresses the definition of beginning of construction and revenue procedure on partnerships for the Enhancement of Carbon Dioxide Sequestration Credit (a.k.a. Section 45Q) CCS tax credit program; the IRS anticipates issuing further guidance on issues such as secure geologic storage, utilization qualifications, and recapture of claimed credits. Maturing incentive programs coupled with workable permitting regulations provide confidence to advance CCS projects in North Dakota and support financial investment to proceed with designing, constructing, and implementing CCS projects at small-scale fuel production facilities. The largest hurdles for CCS implementation at small-scale industrial systems are often business/economic-related (i.e., not technical). Market uncertainty already exists for agriculture-based alternative fuels such as corn ethanol, for which production has increased by ~33%, and prices have correspondingly lowered since 2015. Passing the Section 45Q tax credit program improves economic feasibility for CCS but may require external investors for a small business to achieve maximum benefits. Public–private partnerships with NDIC and DOE have resulted in foundational technical and regulatory knowledge, growing stakeholder confidence, and a pathway to implementation that enables similar industrial CCS projects in the region to advance. This subtask was funded through the EERC–DOE Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FE0024233. Nonfederal funding was provided by NDIC and RTE. The authors would also like to thank CMG, ESRI, IHS, Neuralog, and Schlumberger for allowing the use of their software packages in support of this work.

42 ENGINEERING↗

DOE OSTI2025

Structure and Sulfur: Tuning the Viscoelastic and Surface Properties of Natural Keratin Fibers

Natural keratin fibers, such as wool, possess a complex hierarchical structure that governs their mechanical properties and surface energy. However, the extent to which these characteristics are influenced by combined contributions of structural variations (e.g., fiber diameter, intermediate filament (IF) packing) and chemical composition (e.g., disulfide bond density) remains poorly understood. In this study, we investigate wool fibers from five sheep breeds (Merino, Polwarth, Cheviot, Eider, and Devon) to elucidate how these factors influence viscoelasticity and surface interactions. Using a multimodal approach integrating interfacial and bulk characterization methods, including inverse gas chromatography (IGC), atomic force microscopy-infrared spectroscopy (AFM-IR), X-ray photoelectron spectroscopy (XPS), uniaxial tensile testing, and synchrotron small-angle X-ray scattering (SAXS), we show that the nanometer-thick 18-methyleicosanoic acid (18-MEA) layer is consistently present across all wool types and plays a key role in governing hydrophobicity and surface heterogeneity. A controlled isothermal treatment at 200 °C, designed to cleave disulfide bonds, results in a nearly 40% reduction in specific surface area across all fiber types, accompanied by a significant decrease in tensile strength and 80% reduction in elongation at break for Merino and Devon wool, but limited influence on the mechanical properties of Eider fibers. Furthermore, rate-dependent tensile testing within the elastic regime reveals distinct viscoelastic responses among the fiber types, suggesting that the sulfur-rich protein matrix surrounding IFs and its structure contribute actively to stress partitioning. Altogether, when combined with conclusions from SAXS measurements of IF spacing, our work offers compelling insights into the role of the keratin-associated protein (KAP) matrix in shaping wool fiber mechanics. Differences in mechanical behavior among wool types, despite similar IF spacing or sulfur content, highlight the importance of matrix composition and cross-linking density, suggesting that the molecular architecture of the KAP network may be a dominant factor in determining fiber performance.

X-ray scattering↗

DOE OSTI2020

Phase mediated dynamics of self-propagating Co/Al nanolaminate reactions

The ignition of sputter deposited nanolaminate foils comprised of alternating Co and Al layers results in rapid, self-propagating formation reactions. The propagating waves present after ignition of 150 nm-thick foils are characterized in movie mode dynamic transmission electron microscopy where these are found to have reaction speeds and wave morphology that vary with bilayer thickness. High speed videography reveals different bilayer thickness-wave character relationships in 750 nm- and 7500 nm-thick Co/Al foils. The reaction speed dependencies on bilayer thickness are calculated for each total thickness by treating the effect of radiation loss as a perturbation from an analytical model described by the difference in the heat of reaction measured in calorimetry and the adiabatic heat of product formation. From this model, an effective activation energy, diffusion constant, and flame temperatures are obtained, which allows for an interpretation of the reaction phase variations with laminate design and their effects on propagating wave morphology.

36 MATERIALS SCIENCE↗

NASA NTRS1994

Venus: Vertical accretion of crust and depleted mantle and implications for geological history and processes

Models for the vertical accretion of a basaltic crust and depleted mantle layer on Venus over geologic time predict the eventual development of a net negatively buoyant depleted mantle layer, its foundering and its remixing with the underlying mantle. The consequences of the development of this layer, its loss, and the aftermath are investigated and compared to the geologic record of Venus revealed by Magellan. The young average age of the surface of Venus (several hundred million years), the formation of the heavily deformed tessera regions, the subsequent emplacement of widespread volcanic plains, the presently low rate of volcanic activity, and impact crater population that cannot be distinguished from a completely spatially random distribution, and the small number of impact craters embayed by volcanism, are all consistent with the development of a depleted mantle layer, its relatively rapid loss followed by large-scale volcanic flooding, and its subsequent reestablishment. We outline a 'catastrophic' tectonic resurfacing model in which the foundering of the depleted mantle layer several hundred million years ago caused globally extensive tectonic deformation and obliteration of the cratering record, accompanied by upwelling of warm fertile mantle and its pressure-release melting to produce extensive surface volcanism in the following period. Venus presently appears to be characterized by a relatively thick depleted mantle layer and lithosphere reestablished over the last several hundred million years following the previous instability event inferred to have produced the tessera terrain.

Head, James W.↗

NASA NTRS2009

NASA Tech Briefs, February 2009

Tech Briefs are short announcements of innovations originating from research and development activities of the National Aeronautics and Space Administration. They emphasize information considered likely to be transferable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. Topics covered include: Measuring Low Concentrations of Liquid Water in Soil; The Mars Science Laboratory Touchdown Test Facility; Non-Contact Measurement of Density and Thickness Variation in Dielectric Materials; Compact Microwave Fourier Spectrum Analyzer; InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz; Combinatorial Generation of Test Suites; In-Phase Power-Combined Frequency Tripler at 300 GHz; Electronic System for Preventing Airport Runway Incursions; Smaller but Fully Functional Backshell for Cable Connector; Glove-Box or Desktop Virtual-Reality System; Composite Layer Manufacturing with Fewer Interruptions; Improved Photoresist Coating for Making CNT Field Emitters; A Simplified Diagnostic Method for Elastomer Bond Durability; Complex Multifunctional Polymer/Carbon-Nanotube Composites; Very High Output Thermoelectric Devices Based on ITO Nanocomposites; Reducing Unsteady Loads on a Piggyback Miniature Submarine; Ultrasonic/Sonic Anchor; Grooved Fuel Rings for Nuclear Thermal Rocket Engines; Pulsed Operation of an Ion Accelerator; Autonomous Instrument Placement for Mars Exploration Rovers; Mission and Assets Database; TCP/IP Interface for the Satellite Orbit Analysis Program (SOAP); Trajectory Calculator for Finite-Radius Cutter on a Lathe; Integrated System Health Management Development Toolkit.

Source record↗

DOE OSTI2026

Synthesis and Evaluation of Cu@ZnO Core@Shell Nanowires for Use in the Carbon Dioxide Thermal Reduction Reaction

Copper-based core@shell nanomaterials are of interest for the catalytic hydrogenation of carbon dioxide toward value-added products. In this context, we have developed a facile, microwave-based procedure for the reliable and reproducible synthesis of Cu@ZnO core@shell nanowires. A systematic assessment of the effect of rationally varying various reaction conditions on this protocol was completed in order to better evaluate the growth process of these core–shell motifs. We determined that among different reaction parameters, it was the critical role of reaction time which enabled the quantitatively reliable growth of external shells with tunable thicknesses of up to 20 nm. As a demonstration of the material’s practical viability, catalytic testing was subsequently performed for the reverse water–gas shift reaction (CO 2 + H 2 → CO + H 2 O), with the evolution of the process followed with in situ X-ray diffraction and X-ray absorption spectroscopy in order to probe structural changes and gauge stability. These tests found the catalysts to be effective at converting CO 2 to CO, with notable stability detected in the shell layer and no observed alloying between copper and zinc. Furthermore, our studies support the idea that the Cu–ZnO and CuO x –ZnO interfaces are essential for the effective activation of CO 2 and H 2 .

36 MATERIALS SCIENCE↗

NASA NTRS1988

The budget of biologically active ultraviolet radiation in the earth-atmosphere system

This study applies the concept of a budget to describe the interaction of solar ultraviolet (UV) radiation with the earth-atmosphere system. The wavelength ranges of interest are the biologically relevant UV-B between 280 and 320 nm and the UV-A from 32000 to 400 nm. The Nimbus 7 solar backscattered ultraviolet (SBUV) instrument provides measurements of total column ozone and information concerning cloud cover which, in combination with a simple model of radiation transfer, define the fractions of incident solar irradiance absorbed in the atmosphere, reflected to space, and absorbed at the ground. Results for the month of July quantify the contribution of fractional cloud cover and cloud optical thickness to the radiation budget's three components. Scattering within a thick cloud layer makes the downward radiation field at the cloud base more isotropic than is the case for clear skies. For small solar zenith angles, typical of summer midday conditions, the effective pathlength of this diffuse irradiance through tropospheric ozone is greater than that under clear-sky conditions. The result is an enhanced absorption of UV-B radiation in the troposphere during cloud-covered conditions. Major changes in global cloud cover or cloud optical thicknesses could alter the ultraviolet radiation received by the biosphere by an amount comparable to that predicted for long-term trends in ozone.

Frederick, John E.↗

DOE OSTI2024

Dynamic Surface Incorporation of Pb 2+ Ions at the Actively Dissolving Calcite (104) Surface

The reaction of dissolved Pb 2+ with calcite surfaces at near-equilibrium conditions involves adsorption of Pb 2+ and precipitation of secondary heteroepitaxial Pb-carbonate minerals. A more complex behavior is observed under far-from-equilibrium conditions, including strong inhibition of calcite dissolution, development of microtopography, and near-surface incorporation of multiple monolayers (ML) of Pb 2+ without precipitation of secondary phases [where 1 ML ≡ 1 Ca/20.2 Å 2 , the crystallographic site density of the calcite (104) lattice plane]. However, the mechanistic controls governing far-from-equilibrium reactivity are not well understood. Here, in this study, we observe the interfacial incorporation of dissolved Pb 2+ during the dissolution of calcite (104) surfaces at pH ~3.7 in a flow-through reaction cell, revealing the formation of a ~1 nm thick Pb-rich calcite layer with a total Pb coverage of ~1.4 ML. These observations of the sorbed Pb distribution used resonant anomalous X-ray reflectivity, X-ray fluorescence, and nanoinfrared atomic force microscopy. We propose that this altered surface layer represents a novel sorption mode that is stabilized by conditions of sustained disequilibrium. This behavior may significantly impact the transport of dissolved metals during disequilibrium processes occurring in acid mine drainage and subsurface CO 2 injection and, if appropriately accounted for, could improve the predictive capability of geochemical reactive-transport models.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS1982

Mode characteristics of nonplanar double-heterojunction and large-optical-cavity laser structures

Mode behavior of nonplanar double-heterojunction (DH) and large-optical-cavity (LOC) lasers is investigated using the effective index method to model the lateral field distribution. The thickness variations of various layers for the devices discussed are correlated with the growth characteristics of liquid-phase epitaxy over topographical features (channels, mesas) etched into the substrate. The effective dielectric profiles of constricted double-heterojunction (CDH)-LOC lasers show a strong influence on transverse mode operation: the fundamental transverse mode (i.e., in the plane perpendicular to the junction) may be laterally index-guided, while the first (high)-order mode is laterally index-antiguided. The analytical model developed uses a smoothly varying hyperbolic cosine distribution to characterize lateral index variations. The waveguide model is applied to several lasers to illustrate conditions necessary to convert leaky modes to trapped ones via the active-region gain distribution. Theoretical radiation patterns are calculated using model parameters, and matched to an experimental far-field pattern.

Butler, J. K.↗

NASA NTRS2019

Long Duration Venus Probes and Landers

Planetary probes have long been a tool used by scientists to gain early clues on environments and systems of new planetary targets. This not only fueled the scientific process but also helped prepare for future missions, such as landers, and helped ensure their success. Venus, Earth's sister planet, has been the target of more probes and landers than any other body in our solar system except for Earth and yet many fundamental questions are unanswered. Challenge for Venus Surface Science: This lack of knowledge is a result of the challenging Venus environments. Remote sensing of the surface and portions of the atmosphere is difficult at best due to the thick layers of sulfuric acid clouds and the high pressure supercritical CO2 atmosphere below those clouds. This has hampered the ability of orbiting missions to provide us insight into surface features and processes and thus hides potential clues on interior process from our view. Surface probes and landers face an even more daunting challenge, which is the extreme temperature, pressure and unfriendly chemical composition of the near surface atmosphere. Over 10 assets have landed on the surface yet the longest surviving asset Venera-13 lasted only 127 minutes before succumbing to the extreme temperature. While this and other landers provided valuable new data, the short life impacted ability to understand any temporal processes, for example meteorology, seismic active, and therefore very little is known about the interior and surface atmosphere interactions. New Capability Offering Potential Solutions: Re-cent developments by NASA are offering hope of overcoming the technical challenges of surface operations and life with the use of high temperature electronics and systems. Wide band gap, SiC based electronics have been demonstrated to function successfully for extended periods of time both at 500C, Venus surface temperatures as well as when temperature is combined with the reactive chemistry of the surface atmosphere and the high pressures (over 90 bar pressure at the surface). In addition to electronics a number of other subsystems are in development including power in the form of high temperature batteries and power management devices, communications including antennas, transmitters and other components, materials, and structures and mechanisms. These are all activities under NASA's Long Lived In situ Solar System Exploration (LLISSE) project. Other activities are also funded under NASA's HOTTech program.

Kremic, T.↗

DOE OSTI2024

Interband cascade light-emitting diodes grown on silicon substrates using GaSb buffer layer

Interband cascade light-emitting diodes (ICLEDs) offer attractive advantages for infrared applications, which would greatly expand if high-quality growth on silicon substrates could be achieved. Here, this work describes the formation of threading dislocations in ICLEDs grown monolithically on GaSb-on-Silicon wafers. The epitaxial growth is done in two stages: the GaSb-on-Silicon buffer is grown first, followed by the ICLED growth. The buffer growth involves the nucleation of a 10-nm-thick AlSb buffer layer on the silicon surface, followed by the GaSb growth. The AlSb nucleation layer promotes the formation of 90° and 60° interfacial misfit dislocations, resulting in a highly planar morphology for subsequent GaSb growth that is almost 100% relaxed. The resulting GaSb buffer for growth of the ICLED has a threading dislocation density of ~10 7 /cm 2 after ~3 μm of growth. The fabricated LEDs showed variations in device performance, with some devices demonstrating comparable light–current–voltage curves to those for devices grown on GaSb substrates, while other devices showed somewhat reduced relative performance. Cross-sectional transmission electron microscopy observations of the inferior diodes indicated that the multiplication of threading dislocations in the active region had most likely caused the increased leakage current and lower output power. Enhanced defect filter layers on the GaSb/Si substrates should provide more consistent diode performance and a viable future growth approach for antimonide-based ICLEDs and other infrared devices.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

NASA NTRS2010

Microstructural and Mechanical Evaluation of a Cu-Based Active Braze Alloy to Join Silicon Nitride Ceramics

Self-joining of St. Gobain Si3N4 (NT-154) using a ductile Cu-Al-Si-Ti active braze (Cu-ABA) was demonstrated. A reaction zone approx.2.5-3.5 microns thick) developed at the interface after 30 min brazing at 1317 K. The interface was enriched in Ti and Si. The room temperature compressive shear strengths of Si3N4/Si3N4 and Inconel/Inconel joints (the latter created to access baseline data for use with the proposed Si3N4/Inconel joints) were 140+/-49MPa and 207+/-12MPa, respectively. High-temperature shear tests were performed at 1023K and 1073 K, and the strength of the Si3N4/Si3N4 and Inconel/Inconel joints were determined. The joints were metallurgically well-bonded for temperatures above 2/3 of the braze solidus. Scanning and transmission electron microscopy studies revealed a fine grain microstructure in the reaction layer, and large grains in the inner part of the joint with interfaces being crack-free. The observed formation of Ti5Si3 and AlN at the joint interface during brazing is discussed.

Singh, M.↗

DOE OSTI2022

Conformal Pressure and Fast-Charging Li-Ion Batteries

Batteries capable of extreme fast-charging (XFC) are a necessity for the deployment of electric vehicles. Material properties of electrodes and electrolytes along with cell parameters such as stack pressure and temperature have coupled, synergistic, and sometimes deleterious effects on fast-charging performance. We develop a new experimental testbed that allows precise and conformal application of electrode stack pressure. We focus on cell capacity degradation using single-layer pouch cells with graphite anodes, LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532) cathodes, and carbonate-based electrolyte. In the tested range (10–125 psi), cells cycled at higher pressure show higher capacity and less capacity fading. Additionally, Li plating decreases with increasing pressure as observed with scanning electron microscopy (SEM) and optical imaging. While the loss of Li inventory from Li plating is the largest contributor to capacity fade, electrochemical and SEM examination of the NMC cathodes after XFC experiments show increased secondary particle damage at lower pressure. We infer that the better performance at higher pressure is due to more homogeneous reactions of active materials across the electrode and less polarization through the electrode thickness. Our study emphasizes the importance of electrode stack pressure in XFC batteries and highlights its subtle role in cell conditions.

25 ENERGY STORAGE↗

DOE OSTI2023

NREL 25-cm2 High-Pressure Low-Temperature Electrolysis Cell Hardware (Open Source)

This data resource describes an open-source cell hardware that enables low temperature electrolysis (LTE) testing at elevated pressures. Existing commercial options have several downsides when it comes to R&D testing. They are often not designed for repeated reassembly, may not be able to accommodate porous transport layers with different thicknesses, and do not give state-of-the-art performance. Therefore, this hardware was developed specifically with LTE R&D in mind and its design is being made available to the global LTE community. This work was planned and funded by the U.S. Department of Energy's H2NEW consortium (https://h2new.energy.gov/). The hardware design package (.zip file) details the drawings, auxiliary materials, and procedures required to fabricate, assemble, and operate the National Renewable Energy Laboratory's (NREL's) high-pressure low-temperature electrolysis cells. While the hardware itself—end plates, current collectors, flow fields, bolts and washers, tube fittings—is always the same, the assembly and operating procedures may change depending on the active materials being tested, especially for the membrane. Material-specific assembly and operating procedures will be posted to the H2NEW website as they are developed and validated. Disclaimer: The documents and drawings included in this download package describe a design for a low temperature electrolysis hardware that is intended to comply with leak testing according to ASME B31.1. Safe operation at ambient and elevated pressures is the sole responsibility of the end user, which should be evaluated on a case-by-case basis for each individual cell. Factors affecting the sealing capability may depend on, for example, machining quality, cell assembly components, operating conditions, and operating history. Operation at pressure should only be performed on qualified test stands by qualified operators. NREL/ALLIANCE FOR SUSTAINABLE ENERGY, LLC/DOE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, AND MAKES NO WARRANTY AS TO THE ACCURACY, COMPLETENESS, OR USEFULNESS OF ANY INFORMATION PROVIDED HEREIN. USE OF THIS PACKAGE IS AT THE USER’S OWN RISK.

08 HYDROGEN↗

NASA NTRS1992

Molecular films associated with LDEF

The molecular films deposited on the surface of the Long Duration Exposure Facility (LDEF) originated from the paints and room-temperature-vulcanized (RTV) silicone materials intentionally used on the satellite and not from residual contaminants. The high silicone content of most of the films and the uniformity of the films indicates a homogenization process in the molecular deposition and suggests a chemically most favored composition for the final film. The deposition on interior surfaces and vents indicated multiple bounce trajectories or repeated deposition-reemission cycles. Exterior surface deposits indicated a significant return flux. Ultraviolet light exposure was required to fix the deposited film as is indicated by the distribution of the films on interior surfaces and the thickness of films at the vent locations. Thermal conditions at the time of exposure to ultraviolet light seems to be an important factor in the thickness of the deposit. Sunrise facing (ram direction) surfaces always had the thicker film. These were the coldest surfaces at the time of their exposure to ultraviolet light. The films have a layered structure suggesting cyclic deposition. As many as 34 distinct layers were seen in the films. The cyclic nature of the deposition and the chemical uniformity of the film one layer to the next suggest an early deposition of the films though there is evidence for the deposition of molecular films throughout the nearly six year exposure of the satellite. A final 'spray' of an organic material associated with water soluble salts occurred very late in the mission. This may have been the result of one of the shuttle dump activities.

Crutcher, E. R.↗

NASA NTRS1993

Investigate zero-stress replicated optics

The contracted activities for the procurement of 'Investigate Zero-Stress Replicated Optics' to support the AXAF-S x-ray spectrometer mirrors has been completed. To date four large Wolter I grazing incidence x-ray optical shells have been electroformed from nickel. The mirrors were fabricated utilizing each of two nickel alloy plated aluminum substrates twice. A wide variety of testing has been completed by NASA MSFC and UAH. This testing includes heat treatment control tests, subscale plating and fixture testing, alloy control of the electroless nickel, adhesion and release testing of the gold to electroless nickel, electroforming instrumentation and software and fabrication of subscale models. The full scale shells are one millimeter thick nickel electrodeposited over a thin gold layer which in turn has the optical surface on the inside. The optical surface is the replicate of the surface prepared on the substrate. Appendix I briefly outlines the fabrication process. Major objectives which were shared by UAH and MSFC include the design of facilities, equipment and tooling and procurement of materials and equipment. Process development followed with the fabrication of small scale pilot units. Procurement commenced immediately and equipment and materials were ordered to implement the fabrication of first surface full scale substrates (mandrels) and the second surface electroformed optical components. All principal objectives have been achieved. Inspection of the mirrors in visible and x-ray modes validates that the required performance and the quality can be achieved by an electroforming replication process. A very distinct progressive improvement has been achieved with each of the four mirrors produced. The final mirror exceeded the original goals and set an improved standard for flight hardware. The future goal of a 30 arc second resolution at 8 KEV x-ray appears to be achievable by this process when proper cleanliness and process control is utilized.

Engelhaupt, Darell↗

NASA NTRS1999

The Estimation Surface Latent Heat Flux Over the Ocean and its Relationship to Marine Atmospheric Boundary Layer (MABL) Structure

A new technique combining active and passive remote sensing instruments for the estimation of surface latent heat flux over the ocean is presented. This synergistic method utilizes aerosol lidar backscatter data, multi-channel infrared radiometer data and microwave scatterometer data acquired onboard the NASA P-3B research aircraft during an extended field campaign over the Atlantic ocean in support of the Lidar In-space Technology Experiment (LITE) in September of 1994. The 10 meter wind speed derived from the scatterometers and the lidar-radiometer inferred near-surface moisture are used to obtain an estimate of the surface flux of moisture via bulk aerodynamic formulae. The results are compared with the Special Sensor Microwave Imager (SSM/I) daily average latent heat flux and show reasonable agreement. However, the SSM/I values are biased high by about 30 W/sq m. In addition, the MABL height, entrainment zone thickness and integrated lidar backscatter intensity are computed from the lidar data and compared with the magnitude of the surface fluxes. The results show that the surface latent heat flux is most strongly correlated with entrainment zone top, bottom and the integrated MABL lidar backscatter, with corresponding correlation coefficients of 0.62, 0.67 and 0.61, respectively.

Palm, Stephen P.↗

NASA NTRS2014

The Interior and Orbital Evolution of Charon as Preserved in Its Geologic Record

Pluto and its largest satellite, Charon, currently orbit in a mutually synchronous state; both bodies continuously show the same face to one another. This orbital configuration is a natural end-state for bodies that have undergone tidal dissipation. In order to achieve this state, both bodies would have experienced tidal heating and stress, with the extent of tidal activity controlled by the orbital evolution of Pluto and Charon and by the interior structure and rheology of each body. As the secondary, Charon would have experienced a larger tidal response than Pluto, which may have manifested as observable tectonism. Unfortunately, there are few constraints on the interiors of Pluto and Charon. In addition, the pathway by which Charon came to occupy its present orbital state is uncertain. If Charon's orbit experienced a high-eccentricity phase, as suggested by some orbital evolution models, tidal effects would have likely been more significant. Therefore, we determine the conditions under which Charon could have experienced tidally-driven geologic activity and the extent to which upcoming New Horizons spacecraft observations could be used to constrain Charon's internal structure and orbital evolution. Using plausible interior structure models that include an ocean layer, we find that tidally-driven tensile fractures would likely have formed on Charon if its eccentricity were on the order of 0.01, especially if Charon were orbiting closer to Pluto than at present. Such fractures could display a variety of azimuths near the equator and near the poles, with the range of azimuths in a given region dependent on longitude; east-west-trending fractures should dominate at mid-latitudes. The fracture patterns we predict indicate that Charon's surface geology could provide constraints on the thickness and viscosity of Charon's ice shell at the time of fracture formation.

Tectonics↗