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At least 1,657 records · Page 92

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NASA NTRS2020

An Update on NASA's Lunar Dust Mitigation Strategy

It is well known that the Apollo lu-nar surface missions experienced a number of issues related to dust – which are sometimes referred to as “The Dust Problem”. The jagged, electrostatically charged lunar dust particles can foul mechanisms and alter thermal properties. They tend to abrade textiles and scratch surfaces. NASA and other interested par-ties require an integrated, end-to-end dust mitigation strategy to enable sustainable lunar architectures.

Johansen, M. R.↗

NASA NTRSDate not supplied

Bio Inspired Surface Structures to Mitigate Interfacial Particle Adhesion: A Review

Nature has perfected surface chemical and topographical engineering to enable survival in extreme environments. Biomimetics is a rapidly expanding field where biologically inspired design facilitates elegant, yet practical, solutions across many applications. NASA’s ARTEMIS program focused on lunar missions will require unique ways to solve the challenge of highly abrasive, chemically reactive and electrostatically charged lunar dust that adheres strongly to all exposed surfaces and degrades functionality. While seeking solutions to find a surface for mitigating lunar dust adhesion, we looked at natural terrestrial surfaces that successfully minimize dust adhesion and wear for inspiration. Lunar dust is comprised of highly abrasive particles, more than 90% of which are composed of silicate materials. Adapting to somewhat similar particulates in hot and arid deserts of the world, the sandfish lizard has a skin structure that allows it to swim in the sand with minimum friction and adhesion. Special surface adaptations of the tamarisk plant help protect it from severe sandstorms. The desert scorpion has grooves and bumps on its carapace that have been shown to minimize erosion in the sand. Beyond these examples, there are numerous other natural surfaces that have evolved to mitigate particle adhesion and wear. Several efforts have been made by different researchers to replicate these natural surfaces using methods such as laser patterning, 3D printing, chemical vapor deposition and other physical and chemical processes. The resulting bio-inspired patterned surfaces have shown reduction in interfacial particle adhesion, friction, and wear, among other properties. This paper aims to review published research on the subject that might help develop lunar dust adhesion and wear mitigating material surfaces for future lunar applications.

Lunar dust, Lunar surface, Adhesion mitigation, Bi↗

NASA NTRSDate not supplied

Voltage-Controlled Differential Faraday Rotation from FMNWs and Magnetoelastic Silicone-Nickel Composites

Differential Faraday rotation has been observed from strain-Differential Faraday rotation has been observed from strain-modulated magnetoelastic membranes using millimeter-wave polarimetry at 61.25 GHz. The membranes, consisting of aligned chains of nickel micro-particles embedded in silicone rubber, were manufactured using a roll-to-roll electromagnetic processing line, mounted onto piezoelectric ceramic annuli, and immersed in externally-generated static magnetic fields. Experiments were conducted in which the membranes were periodically stretched by operating the piezoelectric crystals close to their radial resonant frequencies—thereby modulating nickel particle density as well as magnetic material properties. A customized quasi-optical apparatus was used to determine the Faraday-rotation difference between the strained and unstrained states of the magnetoelastic membranes. Possible applications that could emerge from this polymer-based technology include nonreciprocal millimeter-wave components with voltage-controlled frequency response and bio-inspired geomagnetic sensors for GPS-denied navigation. Investigations were conducted to estimate the maximum attainable differential Faraday rotation and the minimum detectable static magnetic field.

nickel↗

NASA NTRS2024

Metal Extraction from Trash via Trash-to-Gas Processing for Use in 3D Printing

This work synergized state-of-the-art trash-to-gas (TtG) and in-space manufacturing (ISM) technologies to successfully extract metals from astronaut waste items for use in 3D printing. This was accomplished by isolating pure aluminum (Al 1235) from astronaut multilayer food packaging via TtG processing, cleaning the extracted aluminum, and preparing it for compatibility with the bound metal deposition (BMD) 3D printing process. A suite of material analyses was performed on the extracted aluminum product to fully characterize the key properties linked to effective additive manufacturing, including particle size distribution, oxygen content quantitation, and elemental composition. Metal extraction from Lunar and Martian regolith has become a significant area of interest for the in-situ resource utilization (ISRU) community to produce metallic equipment for various mission scenarios. However, the extraction of metals from astronaut waste streams has yet to be investigated. This project demonstrated an end-to-end waste metallic reuse process which may garner considerable metal production that would otherwise be disposed of.

Ray Pitts↗

DOE OSTI2026

Characterization of carbonaceous aerosols during TRACER-CAT

Absorbing aerosols (AA) have an important impact on the global radiation budget and cloud properties. The composition and properties of AA can vary substantially throughout the atmosphere, depending on the particle source and the influence of chemical aging. Uncertainties associated with the radiative effects of AA remain substantial. A key contributor to this uncertainty is understanding the extent to which coatings in general, and water uptake especially, alters absorption by AA particles and how this depends on particle composition. We deployed new and existing experimental tools during the Tracking Aerosol Convection Interactions Experiment (TRACER) campaign in Houston, TX as part of the Carbonaceous Aerosols Thrust (CAT) to provide detailed characterization of aerosol optical, chemical, and physical properties. Our TRACER-CAT measurements complemented and expanded on the planned TRACER instrumentation, allowing for more detailed characterization of aerosol properties of relevance to cloud development (a core focus of TRACER), such as the composition of particles that can act as cloud condensation nuclei, than would otherwise be available. Our measurements have allowed for assessment of the relationship(s) between AA optical properties (with a focus on absorption) and the chemical and physical characteristics (including the mixing state of black carbon (BC) containing particles). These field observations occurred in collaboration with Los Alamos National Laboratory in summer 2022 during the TRACER intensive operating period. The instrumentation we co-deployed provided for measurement of (i) multi-wavelength dry aerosol absorption, scattering, and extinction, (ii) the size-dependent composition and abundance of sub-micron aerosol, differentiating between those particles that do and do not contain BC, (iii) BC-specific concentrations and size distributions, (iv) particle size, and (v) the first field measurements at an ARM site of the influence of RH on multi-wavelength absorption by ambient AA. We have leveraged the natural variability of the atmosphere and of aerosol sources in the Houston region to (i) specifically disentangle contributions to light absorption from BC, absorbing organic carbon (brown carbon), and coatings on BC, (ii) characterize the mixing state of BC and assess the factors that give rise to compositional differences between BC-containing and BC-free aerosol, and (iii) establish how water uptake influences absorption and how any such effect depends on particle composition and BC mixing state. Overall, our study contributed to the mission of the Atmospheric System Research program in multiple ways. Through the deployment of complementary, advanced instrumentation for characterization of a wide range of aerosol properties our work helped to maximize the scientific impact of the TRACER campaign. Our work also allowed for development of new insights into the relationship(s) between aerosol composition, hygroscopicity, and the mixing state of BC with aerosol optical properties. Through this, our work has provided knowledge that can improve understanding and model representation of aerosol processes as they affect the Earth’s radiation budget.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS2009

Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer

A film-growth process was developed for polycrystalline mercuric iodide that creates cost-effective, large-area detectors for high-energy charged-particle detection. A material, called a barrier film, is introduced onto the substrate before the normal mercuric iodide film growth process. The barrier film improves the quality of the normal film grown and enhances the adhesion between the film and the substrate. The films grown using this improved technique were found to have adequate signal-to-noise properties so that individual high-energy charged -particle interactions could be distinguished from noise, and thus, could be used to provide an anticoincidence veto function as desired.

Hartsough, Neal↗

NASA NTRS2018

Physical, Chemical, and Petrological Characteristics of Chondritic Materials and Their Relationships to Small Solar System Bodies: Chapter - 2

Chondrite materials with varying abundances of volatile-bearing phases are expected at the destinations for the asteroid sample-return missions Hayabusa2 and OSIRIS-REx. The targets of the missions are 162173 (1999 JU3) Ryugu and 101955 (1999 RQ36) Bennu. Spectroscopic analyses of these asteroids suggest that their surface materials are related to types 1 and 2 carbonaceous chondrites. Some studies suggest that the parent bodies of these chondrites may have also experienced some thermal and/or shock metamorphism. The physical properties of boulders at asteroid surfaces and fine particles in asteroid regoliths are consequences of the diverse processes that fragmented them, mobilized them, and redeposited them in unique accumulations. Sample-return missions are likely to encounter a broad range of carbonaceous chondrite (CC)-like materials, to which aqueous alteration, thermal, and shock metamorphism imparted changes affecting their sub-micron- to meter-scale physical properties. Consequently, implementation of scale-dependent analytical techniques to the study of the chemical, physical, and geotechnical characteristics of these CC-like materials is fundamental to safe mission operations, sample selection, and return. However, most of the available knowledge for informing and formulating expectations about regolith processes, products, and properties on carbonaceous small bodies comes from missions that studied anhydrous (e.g., Itokawa studied by Hayabusa) and/or much larger asteroids (e.g., Vesta studied by Dawn). No previous mission is likely directly relevant to small ice-free carbonaceous NEOs 162173 Ryugu or 101955 Bennu, although the Rosetta Spaceraft performed a flyby of the large asteroid Lutetia which has variously been classified as M and C type (Pätzold et al., 2011). Carbonaceous chondrites carry the best record of the history, distribution, and activity of water in the early solar system. Ordinary and Enstatite chondrites carry only partial records, but these are still critical to understanding the full story. We will describe the records of water-rock interactions on asteroids, as recorded in these meteorites, with particular emphasis on the timing, nature, settings, and fluid compositions. An integral part of this story is the rare, but fortunate, preservation of actual early solar system water as aqueous fluid inclusions.

Zolensky, Michael E.↗

NASA NTRS1999

The Features of Self-Assembling Organic Bilayers Important to the Formation of Anisotropic Inorganic Materials in Microgravity Conditions

There is a growing need for inorganic anisotropic particles in a variety of materials science applications. Structural, optical, and electrical properties can be greatly augmented by the fabrication of composite materials with anisotropic microstructures or with anisotropic particles uniformly dispersed in an isotropic matrix. Examples include structural composites, magnetic and optical recording media, photographic film, certain metal and ceramic alloys, and display technologies including flat panel displays. While considerable progress has been made toward developing an understanding of the synthesis of powders composed of monodispersed, spherical particles, these efforts have not been transferred to the synthesis of anisotropic nanoparticles. The major objective of the program is to develop a fundamental understanding of the growth of anisotropic particles at organic templates, with emphasis on the chemical and structural aspects of layered organic assemblies that contribute to the formation of anisotropic inorganic particles.

Talham, Daniel R.↗

DOE OSTI2020

An energy-conserving and asymptotic-preserving charged-particle orbit implicit time integrator for arbitrary electromagnetic fields

Here we present a new implicit asymptotic preserving time integration scheme for charged-particle orbit computation in arbitrary electromagnetic fields. The scheme is built on the Crank-Nicolson integrator and continues to recover full-orbit motion in the small time-step limit, but also recovers all the first-order guiding center drifts as well as the correct gyroradius when stepping over the gyration time-scale. In contrast to previous efforts in this direction, the new scheme also features exact energy conservation. In the derivation of the scheme, we find that a new numerical time-scale is introduced. This scale is analyzed and the resulting restrictions on time-step are derived. Based on this analysis, we develop an adaptive time-stepping strategy the respects these constraints while stepping over the gyration scale when physically justified. It is shown through numerical tests on single-particle motion that the scheme's energy conservation property results in tremendous improvements in accuracy, and that the scheme is able to transition smoothly between magnetized and unmagnetized regimes as a result of the adaptive time-stepping.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1995

Alfven Waves, Alpha Particles, and Pickup Ions in the Solar Wind

Past studies of the properties of Alfven waves in the solar wind have indicated that the amplitude of the velocity fluctuations is almost always smaller than expected on the basis of the amplitude of the field fluctuations, even when plasma anisotropy is taken into account. Also, the alpha particles often do not participate in the wave motions because they "surf" on the proton fluid waves.

Alfven↗

DOE OSTI2021

3D Printing of Transparent Silicone Elastomers

Here in this paper, inks for transparent elastomers that are formulated by matching the refractive index of silica and polysiloxanes are described. The transparent inks transmit up to ≈90% of 700 nm light through 1 cm and remain transparent when solidified. The inks and solidified materials exhibit a thermochromic effect. This thermochromic effect can be controlled by the refractive index mismatch. Transparency may increase or decrease as temperature increases, depending on the refractive index mismatch of the base polysiloxane and silica. It is found that the rheological properties of the ink depend on the distribution of silica particles, which is dictated by silica functionality, weight content, and processing. Siloxane precursors that vary in chemical functionality are introduced to tailor the mechanical properties of the printed elastomers, which obtain stretchability >65% along with a tensile modulus of 1.9 MPa. After optimizing siloxane chemistry and ink processing, the authors are able to print transparent elastomers. Potential applications are demonstrated for printed structures by printing encapsulation structures for light-emitting diodes, semitransparent dye-filled structures, a microfluidic mixing device, and a multimaterial structure that exhibits temperature-dependent camouflage.

36 MATERIALS SCIENCE↗

NASA NTRS2022

The impacts of immersion ice nucleation parameterizations on Arctic mixed-phase stratiform cloud properties and the Arctic radiation budget in GEOS-5

The influence of four different immersion freezing parameterizations on Arctic clouds and the top-of-the atmosphere (TOA) and surface radiation fluxes is investigated in the fifth version of the National Aeronautics and Space Administration (NASA) Goddard Earth Observing System (GEOS-5) with sea surface temperature, sea ice fraction and aerosol emissions held fixed. The different parameterizations were derived from a variety of sources, including classical nucleation theory, field and laboratory measurements. Despite the large spread in the ice-nucleating particle (INP) concentrations in the parameterizations, the cloud properties and radiative fluxes had a tendency to form two groups, with the lower INP concentration category producing larger water path and low-level cloud fraction during winter and early spring, whereas the opposite occurred during the summer season. The stability of the lower troposphere was found to strongly correlate with low-cloud fraction, and along with the effect of ice nucleation, ice sedimentation and melting rates, appears to explain the spring-to-summer reversal pattern in the relative magnitude of the cloud properties between the two categories of simulations. The strong modulation effect of the liquid phase on immersion freezing led to the successful simulation of the characteristic Arctic cloud structure, with a layer rich in supercooled water near cloud top and ice and snow at lower levels. Comparison with satellite retrievals and in situ data suggest that simulations with low INP concentrations more realistically represent Arctic clouds and radiation.

Arctic↗

NASA NTRS1995

Radiative impact of aerosols generated from biomass burning

Atmospheric aerosol particles play a vital role in the Earth's radiative energy budget. They exert a net cooling influence on climate by directly reflecting the solar radiation to space and by modifying the shortwave reflective properties of clouds. Each year, increasing amounts of aerosol particles are released into the atmosphere due to biomass burning, dust storms, forest fires, and volcanic activity. These particles significantly perturb the radiative balance on local, regional, and global scales. While the detection of aerosols over water is a well established procedure, the detection of aerosols over land is often difficult due to the poor contrast between the aerosols and the underlying terrain. In this study, we use textural measures in order to detect aerosols generated from biomass burning over South America, using AVHRR data. The regional radiative effects are then examined using ERBE data. Preliminary results show that the net radiative forcing of aerosols is about -36 W/sq m.

Christopher, Sundar A.↗

DOE OSTI2025

Generating multi-scale Li-ion battery cathode particles with radial grain architectures using stereological generative adversarial networks

Abstract Understanding structure-property relationships of Li-ion battery cathodes is crucial for optimizing rate-performance and cycle-life resilience. However, correlating the morphology of cathode particles, such as in LiNi0.8Mn0.1Co0.1O2 (NMC811), and their inner grain architecture with electrode performance is challenging, particularly, due to the significant length-scale difference between grain and particle sizes. Experimentally, it is not feasible to image such a high number of particles with full granular detail. A second challenge is that sufficiently high-resolution 3D imaging techniques remain expensive and are sparsely available at research institutions. Here, we present a stereological generative adversarial network-based model fitting approach to tackle this, that generates representative 3D information from 2D data, enabling characterization of materials in 3D using cost-effective 2D data. Once calibrated, this multi-scale model can rapidly generate virtual cathode particles that are statistically similar to experimental data, and thus is suitable for virtual characterization and materials testing through numerical simulations. A large dataset of simulated particles with inner grain architecture has been made publicly available.

25 ENERGY STORAGE↗

DOE OSTI2025

Protein Coatings Dictate the Dispersibility and Stability of Hydrophobic Zeolitic-Imidazolate Frameworks in Water

Metal–organic frameworks are promising materials for many biomedical technologies due to their ability to store and release large quantities of guest molecules in a predictable and tunable fashion. In biological fluids, proteins readily adsorb to the external surfaces of metal–organic framework particles through a combination of hydrophobic and electrostatic interactions. However, much remains to be understood about the nature of these protein coatings and how they influence the bulk properties of aqueous dispersions of metal–organic frameworks. Here, in this work, we show that a variety of proteins can be used to manipulate the properties of aqueous dispersions of zeolitic-imidazolate framework (ZIF) particles. Specifically, noncovalently associated protein coatings promote the formation of dispersions of hydrophobic ZIFs in water with high colloidal and hydrolytic stability, as long as the density of adsorbed proteins exceeds a critical, protein-dependent threshold. Further, these dispersions feature low viscosity and complete retention of gas carrying capacity. The wide range of properties accessible with protein coatings provides a highly modular approach to design hydrophobic metal–organic frameworks with properties tailored for specific biological applications.

adsorption↗

NASA NTRS2004

Characterization of Asian Dust Properties Near Source Region During ACE-Asia

Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian aerosols is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia campaign, we have acquired ground- based (temporal) and satellite (spatial) measurements to infer aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over this region. The inclusion of flux measurements permits the determination of aerosol radiative flux in addition to measurements of loading and optical depth. At the time of the Terra/MODIS, SeaWiFS, TOMS and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. In this paper, we will demonstrate new capability of the Deep Blue algorithm to track the evolution of the Asian dust storm from sources to sinks. Although there are large areas often covered by clouds in the dust season in East Asia, this algorithm is able to distinguish heavy dust from clouds over the entire regions. Examination of the retrieved daily maps of dust plumes over East Asia clearly identifies the sources contributing to the dust loading in the atmosphe~~. We have compared the satellite retrieved aerosol optical thickness to the ground-based measurements and obtained a reasonable agreement between these two. Our results also indicate that there is a large difference in the retrieved value of spectral single scattering albedo of windblown dust between different sources in East Asia.

Tsay, Si-Chee↗

NASA NTRS2020

The Precipitation Imaging Package: Assessment of Microphysical and Bulk Characteristics of Snow

Remote-sensing observations are needed to estimate the regional and global impacts of snow. However, to retrieve accurate estimates of snow mass and rate, these observations require augmentation through additional information and assumptions about hydrometeor properties. The Precipitation Imaging Package (PIP) provides information about precipitation characteristics and can be utilized to improve estimates of snowfall rate and accumulation. Here, the goal is to demonstrate the quality and utility of two higher-order PIP-derived products: liquid water equivalent snow rate and an approximation of volume-weighted density called equivalent density. Accuracy of the PIP snow rate and equivalent density is obtained through intercomparison with established retrieval methods and through evaluation with colocated ground-based observations. The results confirm the ability of the PIP-derived products to quantify properties of snow rate and equivalent density, and demonstrate that the PIP produces physically realistic snow characteristics. When compared to the National Weather Service (NWS) snow field measurements of six-hourly accumulation, the PIP-derived accumulations were biased only +2.48% higher. Additionally, this work illustrates fundamentally different microphysical and bulk features of low and high snow-to-liquid ratio events, through assessment of observed particle size distributions, retrieved mass coefficients, and bulk properties. Importantly, this research establishes the role that PIP observations and higher-order products can serve for constraining microphysical assumptions in ground-based and spaceborne remotely sensed snowfall retrievals.

Claire Pettersen↗

DOE OSTI2024

From solid surfactants to micromotors: An overview of the synthesis and applications of heterogeneous particles

Colloid science has classically concerned itself with the investigation of the properties of dispersed phases in a bulk medium. This has led to the development of a rich amount of chemistry, physics, and engineering that have facilitated the evolution and maturation of this field. One of the many developments made over the last 30 years is the introduction of particles that are heterogeneous in chemistry and shape. These heterogeneities can introduce behaviors that are not achievable in homogeneous systems and that are specific to the type and class of nonuniformity. This has led to the development of numerous technologies, two of which are Janus micromotors and solid surfactants. Here, this review aims to familiarize the reader with the field of heterogeneous particles. We begin with an overview of various synthetic methods to produce colloidal particles that are heterogeneous in chemistry and shape. We then discuss their use as solid surfactants and autonomous micromotors. We then close by summarizing and providing a future perspective on the field.

36 MATERIALS SCIENCE↗