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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Li6V3P8O29 by Materials Project

Li6V3P8O29 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with four PO4 tetrahedra, an edgeedge with one LiO6 octahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.94–2.17 Å. In the second Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.95–2.16 Å. In the third Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.94–2.14 Å. In the fourth Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with three VO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 68–69°. There are a spread of Li–O bond distances ranging from 1.91–2.17 Å. In the fifth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with four PO4 tetrahedra, an edgeedge with one LiO6 octahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.94–2.17 Å. In the sixth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with four PO4 tetrahedra, an edgeedge with one LiO6 octahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.94–2.18 Å. In the seventh Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.95–2.25 Å. In the eighth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.94–2.17 Å. In the ninth Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with three VO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedral tilt angles are 68°. There are a spread of Li–O bond distances ranging from 1.83–2.23 Å. In the tenth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.95–2.24 Å. In the eleventh Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.95–2.24 Å. In the twelfth Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with six PO4 tetrahedra and edges with three LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 2.34–2.47 Å. There are six inequivalent V4+ sites. In the first V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and edges with two LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.85–2.01 Å. In the second V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.86–2.04 Å. In the third V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.86–2.04 Å. In the fourth V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and edges with two LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.86–2.01 Å. In the fifth V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and edges with two LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.85–2.01 Å. In the sixth V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.88–2.01 Å. There are sixteen inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–57°. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–45°. There are a spread of P–O bond distances ranging from 1.50–1.60 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–45°. There are a spread of P–O bond distances ranging from 1.50–1.60 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three VO6 octahedra and corners with four LiO4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. There is one shorter (1.50 Å) and three longer (1.57 Å) P–O bond length. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three VO6 octahedra and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–34°. There are a spread of P–O bond distances ranging from 1.49–1.59 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–56°. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–49°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–57°. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the ninth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–47°. There are a spread of P–O bond distances ranging from 1.49–1.62 Å. In the tenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–46°. There are a spread of P–O bond distances ranging from 1.50–1.60 Å. In the eleventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–48°. There are a spread of P–O bond distances ranging from 1.49–1.62 Å. In the twelfth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three VO6 octahedra and corners with three LiO4 tetrahedra. The corner-sharing octahedral tilt angles are 35°. There is one shorter (1.49 Å) and three longer (1.59 Å) P–O bond length. In the thirteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three VO6 octahedra and a cornercorner with one LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 30–31°. There are a spread of P–O bond distances ranging from 1.49–1.58 Å. In the fourteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–48°. There are a spread of P–O bond distances ranging from 1.51–1.61 Å. In the fifteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–48°. There are a spread of P–O bond distances ranging from 1.51–1.61 Å. In the sixteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–48°. There are a spread of P–O bond distances ranging from 1.49–1.62 Å. There are fifty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to two Li1+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V4+, and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Li1+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V4+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one V4+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two Li1+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one V4+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V4+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a linear geometry to one Li1+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a sing

36 MATERIALS SCIENCE↗
DOE OSTI2025

AmeriFlux CA-LU1 Steen River

This is the AmeriFlux version of the carbon flux data for the site CA-LU1 Steen River. Site Description - Steen River is a peat plateau that burned in extreme fire conditions in late May 2019. Prior to the fire the site was likley and open canopy of stunted black spruce and a ground layer of Labrador tea shurbs and lichen or sphagnum with around >150cm of peat. All low shrubs were consumed by the fire, Sphagnum mosees were singed but not combusted, all the trees deceased with needles, tertiary, secondary branches consumed by fire and >30% of primary branches rmained.

Schulze, Christopher [University of Alberta]↗
DOE OSTI2026

AmeriFlux FLUXNET-1F CA-LU1 Steen River

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-LU1 Steen River. This is the FLUXNET version of the carbon flux data for the site CA-LU1 Steen River produced by applying the standard ONEFlux (1F) software. Site Description - Steen River is a peat plateau that burned in extreme fire conditions in late May 2019. Prior to the fire the site was likley and open canopy of stunted black spruce and a ground layer of Labrador tea shurbs and lichen or sphagnum with around >150cm of peat. All low shrubs were consumed by the fire, Sphagnum mosees were singed but not combusted, all the trees deceased with needles, tertiary, secondary branches consumed by fire and >30% of primary branches rmained.

Schulze, Christopher [University of Alberta]↗
DOE OSTI2023

Single-crystal elasticity of (Al,Fe)-bearing bridgmanite up to 82 GPa

Abstract Thermoelastic properties of mantle candidate minerals are essential to our understanding of geophysical phenomena, geochemistry, and geodynamic evolutions of the silicate Earth. However, the lower-mantle mineralogy remains much debated due to the lack of single-crystal elastic moduli (Cij) and aggregate sound velocities of (Al,Fe)-bearing bridgmanite, the most abundant mineral of the planet, at the lower mantle pressure-temperature (P-T) conditions. Here we report single-crystal Cij of (Al,Fe)-bearing bridgmanite, Mg0.88Fe0.1Al0.14Si0.90O3 (Fe10-Al14-Bgm) with Fe3+/ΣFe = ~0.65, up to ~82 GPa using X-ray diffraction (XRD), Brillouin light scattering (BLS), and impulsive stimulated light scattering (ISLS) measurements in diamond-anvil cells (DACs). Two crystal platelets with orientations of (–0.50, 0.05, –0.86) and (0.65, –0.59, 0.48), that are sensitive to deriving all nine Cij, are used for compressional and shear wave velocity (νP and νS) measurements as a function of azimuthal angles over 200° at each experimental pressure. Our results show that all Cij of singe-crystal Fe10-Al14-Bgm increase monotonically with pressure with small uncertainties of 1–2% (±1σ), except C55 and C23, which have uncertainties of 3–4%. Using the third-order Eulerian finite-strain equations to model the elasticity data yields the aggregate adiabatic bulk and shear moduli and respective pressure derivatives at the reference pressure of 25 GPa: KS = 326 ± 4 GPa, µ = 211 ± 2 GPa, KS′ = 3.32 ± 0.04, and µ′ = 1.66 ± 0.02 GPa. The high-pressure aggregate νS and νP of Fe10-Al14-Bgm are 2.6–3.5% and 3.1–4.7% lower than those of MgSiO3 bridgmanite end-member, respectively. These data are used with literature reports on bridgmanite with different Fe and Al contents to quantitatively evaluate pressure and compositional effects on their elastic properties. Comparing with one-dimensional seismic profiles, our modeled velocity profiles of major lower-mantle mineral assemblages at relevant P-T suggest that the lower mantle could likely consist of about 89 vol% (Al,Fe)-bearing bridgmanite. After considering uncertainties, our best-fit model is still indistinguishable from pyrolitic or chondritic models.

Geochemistry & Geophysics↗
DOE OSTI2020

Development of Tools Training and Outreach to Address Solar Glare and Flux-Related Avian Impacts

Millions of dollars and significant resources are being spent by developers of utility-scale solar photovoltaic (PV) and concentrating solar power (CSP) plants to address federal and local requirements regarding glare and avian hazards. Solar glare can occur from the glass surfaces of PV modules and from mirrors in CSP systems, which can produce safety and health risks for pilots, motorists, and residents located near these systems. In addition, concentrated solar flux at CSP plants has the potential to singe birds as they fly through regions of high solar flux. This work will develop tools to characterize and mitigate these potential hazards, which will address regulatory policies and reduce costs and efforts associated with the proposed deployment of gigawatts of solar energy systems throughout the nation. The development of standardized and publicly available tools to address these regulatory policies and ensure public and environmental safety is an appropriate role for the government.

14 SOLAR ENERGY↗
DOE OSTI2024

Focusing Optics for Axion Detection: Simulating Sensing Enhancements of Photons in InfraBREAD

The Broadband Reflector Experiment for Axion Detection (BREAD) will search for axions, a promising particle candidate for dark matter, in the high mass range of [$10^{-3}$,1]eV. BREAD acts like a telescope for dark matter, using a parabolic reflector to direct axion-induced photons onto a precise focal spot. InfraBREAD is the experimental version designed to detect photons resulting from axions with infrared frequency using a 1mm × 1mm Superconducting Nanowire Singe Photon Detector (SNSPD). However, at this frequency scale two problems arise: 1) the focal spot becomes smeared across an area larger than the size of the SNSPD detector; 2) any millimeter-scale misalignment shifts in the SNSPD can greatly diminish photon signal. This study performed simulations of novel optical configurations of lenses and reflectors placed around the SNSPD to achieve a greater efficiency than the SNSPD alone through both of these effects. One optical setup was identified called the “Parabolo id to Winston Cone (PTW) Configuration,” which exploits the optics of parabolic reflectors to focus incoming photons from the larger area of the smeared focal spot onto the smaller 1mm 2 area of the detector. The PTW configuration demonstrated overall improvements in efficiency by around 10% through misalignment shifts, with a maximal improvement of 55% in one region.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Aerosol Particle Mixing State and Composition at AMF3 (Interim Field Campaign Report)

The campaign is designed to support deployment of aerosol sampling equipment at the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility’s third ARM Mobile Facility (AMF3) to enable both singe-particle and bulk characterization of the aerosol particles at the field site in Bankhead National Forest, northern Alabama. We are proposing to do this work as part of our proposal “Generalizing aerosol mixing state: synthesis from observations and connection to models,” which has the pre-proposal tracking number PRE-0000035878. The full proposal has Dr. Rachel O’Brien as the Principal Investigator (PI) and Dr. Andy Ault and Dr. Nicole Riemer as Co-PIs. We sought to deploy instruments in winter 2025 and summer 2025 to obtain samples in different seasons, but were delayed by AMF3 set-up and availability of students and PIs. We just completed our first deployment this summer (2025) and we are interested in obtaining samples during this upcoming fall and winter to see the seasonal trends in aerosol mixing state at the site. This will provide a comparison of the impact of biogenic emissions on the mixing state and the chemical composition of the aerosol particles. Overall, the proposed study will provide key information regarding the mixing state of aerosol particles at AMF3 with direct ties to impacts of the particles on cloud formation and light scattering/absorption. From our deployment that ended las week we have some visible observations from our samples. We are observing a regular amount of black carbon on stage 6 of our Micro-Orifice Uniform Deposit Impactor (MOUDI) and we have also observed some short, large increases in aerosol loading. We hope to continue observations of these two features to determine the sources/aging for the black carbon and the physical mixing state as well as the sources for the short (a few minutes) increases in the aerosol loading and determine if the source for these is dust or sea salt or another source. We are also interested in comparing the black carbon we see here to samples collected during the agriculture burns in January/February and in comparing the larger particles to bioaerosols in the spring. To obtain these comparisons, we will need to collect more samples in the other seasons. Finally, we have some size-resolved particle collectors that can be deployed at the same time as the tethered balloon launches. We have discussed with Swarup China about trying to get the timing to work in August and we are interested in coordinating again later, if possible. This will give us ground-level and vertical aerosol mixing state sample sets that will be very exciting to analyze.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Insights of warm-cloud biases in Community Atmospheric Model 5 and 6 from the single-column modeling framework and Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) observations

There has been a growing concern that most climate models predict precipitation that is too frequent, likely due to lack of reliable subgrid variability and vertical variations in microphysical processes in low-level warm clouds. In this study, the warm-cloud physics parameterizations in the singe-column configurations of NCAR Community Atmospheric Model version 6 and 5 (SCAM6 and SCAM5, respectively) are evaluated using ground-based and airborne observations from the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) field campaign near the Azores islands during 2017–2018. The 8-month single-column model (SCM) simulations show that both SCAM6 and SCAM5 can generally reproduce marine boundary layer cloud structure, major macrophysical properties, and their transition. The improvement in warm-cloud properties from the Community Atmospheric Model 5 and 6 (CAM5 to CAM6) physics can be found through comparison with the observations. Meanwhile, both physical schemes underestimate cloud liquid water content, cloud droplet size, and rain liquid water content but overestimate surface rainfall. Modeled cloud condensation nuclei (CCN) concentrations are comparable with aircraft-observed ones in the summer but are overestimated by a factor of 2 in winter, largely due to the biases in the long-range transport of anthropogenic aerosols like sulfate. We also test the newly recalibrated autoconversion and accretion parameterizations that account for vertical variations in droplet size. Compared to the observations, more significant improvement is found in SCAM5 than in SCAM6. This result is likely explained by the introduction of subgrid variations in cloud properties in CAM6 cloud microphysics, which further suppresses the scheme's sensitivity to individual warm-rain microphysical parameters. The predicted cloud susceptibilities to CCN perturbations in CAM6 are within a reasonable range, indicating significant progress since CAM5 which produces an aerosol indirect effect that is too strong. The present study emphasizes the importance of understanding biases in cloud physics parameterizations by combining SCM with in situ observations.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1966

Concave-convex growth spirals.

The simple model for introduction of a screw dislocation into a crystal leaves a step in those surfaces of the crystal that intersect the axis of the screw dislocation such that the Burgers vector has a finite component perpendicular to the surfaces. When two parallel surfaces of a crystal intersect the same screw dislocation, the resultant step, on opposite sides of the crystal, face in opposite directions. Consequently, when two such surfaces grow by accretion of the molecules at the steps, the steps wind themselves into spirals that appear to have opposite senses of rotation when viewed along the axis of the screw dislocation. Furthermore, the growth structure that results is a plano convex cone or pyramid centered on the screw dislocation. When growth occurs simultaneously on both sides of a crystal, a doubly convex structure will develop under the control of a singe screw dislocation.

Crystal growth↗
NASA NTRS1970

Multibody Interplanetary Swingby Trajectories /MIST-1/

Computer program incorporates new isolation procedure to determine interplanetary trajectories which utilize a maximum of three flybys. Program also computes singe planet flybys and direct transfer trajectories. The three principle systems employed in MIST-1 use as their fundamental plane the mean plane of the earth's orbit around the sun.

Davis, D. A.↗
NASA NTRS1970

The crystallography of lunar troilite

Crystallography of euhedral singe crystals from lunar troilite indicating hexagonal forms consistent with high temperature NiAs type structure

Evans, H. T., Jr.↗
NASA NTRS1976

Sound-producing dune and beach sands

Acoustic and seismic outputs of booming sands and singing (squeaking) sands in response to shearing are investigated, with samples of silent sands studied for controls. A vertical-axis geophone buried at shallow depth and an air microphone were used in the studies. The frequency spectra of the acoustic and seismic responses, propagation delays, comparison of acoustic and seismic traces, grain size and grain surface texture, particle morphology, coherent behavior of grains in assemblages, and relation to prevalent local winds were studied. Mechanisms are still obscure and disputed; slumping and avalanches were induced artificially in some studies. Existence of booming dune phenomena on Mars or on the moon is conjectured.

Lindsay, J. F.↗
NASA NTRS1980

Spacecraft for flight in the atmosphere of Venus

Possible configurations of space vehicles which would be delivered to Venus by rocket system in order to autonomously carry out flights in an automatic (and possibly piloted) mode are considered with respect to mission and flight altitude. Base (high altitude) vehicles, operating at pressure, sendity, and temperature corresponding to those on Earth at sea level, will have little maneuverability, will serve as carriers for equipment, scientific devices, and other cargo, and will study the gas composition of the Venus atmosphere from above. Low altitude vehicles will explore the planet from flight altitude in the vicinity of the planet's surface, as well as land on it. Analogous to deep submergence vehicles such as the bathyscaphe and the bathyplane, they will have a certain amount of maneuverability and will study the atmospheric boundary layer from below. The advantages of aerostats in this environment are discussed. Drawings of the aerostatic base station, the variable-length aerostatic sing vehicle, and the hybrid aerostatic vehicle with attached wings are included.

Moskalenko, G. M.↗
NASA NTRS1982

Hormone purification by isoelectric focusing in space

The performance of a ground-prototype of an apparatus for recycling isoelectric focusing was evaluated in an effort to provide technology for large scale purification of peptide hormones, proteins, and other biologicals. Special emphasis was given to the effects of gravity on the function of the apparatus and to the determination of potential advantages deriveable from its use in a microgravity environment. A theoretical model of isoelectric focusing sing chemically defined buffer systems for the establishment of the pH gradients was developed. The model was transformed to a form suitable for computer simulations and was used extensively for the design of experimental buffers.

Bier, M.↗
NASA NTRS1985

The modulation features of the long-period cosmic ray variations in connection with the sign change of the general magnetic field of the Sun

On the basis of the model and experimental investigations, the spatial distribution of cosmic ray anisotropy for the different epochs of solar activity is studied. A solution is offered to the anisotropic diffusion equation with regard to the electromagnetic conditions for the periods of minimum and maximum solar activity and cosmic ray particle drift in a regular interplanetary magnetic field. It is shown that the long period changes amplitude and phase of the diurnal variations of cosmic rays is limited not only by convection and diffusion of particles but also by the drift effect before and after the sing change of the general magnetic field of the Sun. The calculated model is compared with the results obtained on the basis of an analysis of the experimental data from the neutron super monitor station, and it is shown that for the periods when the lines of magnetic force of the Sun come from the Northern Hemisphere the phase of the first harmonic diurnal variation is shifted forwards to an earlier time.

Iskra, K.↗
NASA NTRS1988

Range data description based on multiple characteristics

An algorithm for describing range images based on Mean curvature (H) and Gaussian curvature (K) is presented. Range images are unique in that they directly approximate the physical surfaces of a real world 3-D scene. The curvature parameters are derived from the fundamental theorems of differential geometry and provides visible invariant pixel labels that can be used to characterize the scene. The sign of H and K can be used to classify each pixel into one of eight possible surface types. Due to the sensitivity of these parameters to noise the resulting HK-sing map does not directly identify surfaces in the range images and must be further processed. A region growing algorithm based on modeling the scene points with a Markov Random Field (MRF) of variable neighborhood size and edge models is suggested. This approach allows the integration of information from multiple characteristics in an efficient way. The performance of the proposed algorithm on a number of synthetic and real range images is discussed.

Al-Hujazi, Ezzet↗
NASA NTRS1922

Skin frictional resistance of plane surfaces in air

Given here is the most recent research on skin frictional resistance of plane surfaces in air that was conducted by Dr. Wieselsberger under the direction of Dr. Prandtl of Gottingen University. In all, 16 models were tested. These were divided into four groups, as follows: 1) cloth, in the original condition; 2) cloth, with the nap singed off; 3) cloth, with three coats of dope; and 4) cloth, with six coats of dope. Each group consisted of four models of uniform width, 1 meter, and of lengths of 0.5, 1.0, 1.5, and 2.0 meters. Tests were made on each model at speeds varying from 7.0 to 50 meters per second. The observed total resistance was corrected for the form resistance which was obtained from the pressure distribution on the end of the model. Previous tests had shown that the form resistance due to the rounded front edge used on the models was negligible. The results are expressed in terms of the absolute coefficient of frictionless resistance, C(sub F).

Diehl, W S↗