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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

Dendroarchaeological Analysis of the Terminal Warehouse in New York City Reveals A History of Long-Distance Timber Transport During the Gilded Age

The Gilded Age of the late 19th century marked a period of rapid development and urbanization in New York City, U.S. To accommodate the high demand in wood products during that time, the timbers used for development of the city were increasingly sourced from locations distant from the northeastern United States. The Terminal Warehouse in the Chelsea neighborhood of New York City was one of many large buildings erected during this period of city expansion, and is an important symbol of New York City commerce during the late 1800s. To determine the history and provenance of timbers used in the construction of the Terminal Warehouse, we used tree-ring analysis on longleaf pine (Pinus palustris Mill.) joists that were original to the building. The ring-width patterns on the joists cross dated well internally, suggesting a common origin of the sampled lumber. Further, our Terminal Warehouse tree-ring chronology (1512–1891 C.E.) correlated strongly with existing tree-ring chronologies from western/central Georgia and eastern Alabama, indicating that the timbers were extracted from this region of the southeastern United States. The provenancing and dating of the Terminal Warehouse timbers underscores the important role that southern pines played in the expansion and development of New York City during the Gilded Age.

Dendroprovenance↗
NASA NTRSDate not supplied

Cosmic Ray Exposure Ages, Bulk and Isotopic H, C, and N Compositions of Dominion Range (DOM) CO3 Carbonaceous Chondrites and Implications for Pairing

Over 20 CO3 chondrites have been re-covered in the Dominion Range (DOM) dense collection area (DCA) of the Transantarctic Mountains by ANSMET (Antarctic Search for Meteorites) across 6 field seasons. Because of the significant masses involved and huge community interest in the most primitive samples of all carbonaceous chondrite classes such as the CO3s, we have undertaken a de-tailed assessment of the pairings and petrologic types using field relations, macroscopic observations, petrography, olivine compositions, and bulk and isotopic H, C, N compositions, and noble gas abundances and isotopes for cosmic ray exposure (CRE) ages, for all specimens. Most recently, teams during the 2018-19 and 2019-20 seasons recovered 10 new CO3 samples. Here we report new H, C, and N bulk and isotopic data, as well as CRE ages, for these 10 samples and DOM 10900 (which has some unique properties and may not be a CO chondrite). This completes the characterization of all known CO3s from DOM, allowing a thorough assessment of possible pairing relations.

chondrite↗
NASA NTRSDate not supplied

Determining Surface Exposure Ages of Regolith Grains in Lunar Core Sample 73002 By Investigating Solar Particle Irradiation Damage

Space weathering causes the surface soils of airless bodies like the Moon to be micro-structurally and chemically altered by exposure to micrometeoroid bombardment and solar wind irradiation. These alterations accumulate in surface grains with continued residence in the uppermost millimeters of regolith. Low energy solar wind ions (largely H+ and He+) produce a layer of radiation damage as they become implanted in grain surfaces. Also present are solar energetic particle (SEP) tracks, which are nanoscale lineations within grain interiors formed by heavy, high-energy ions (mainly Fe group nuclei) penetrating up to millimeters below the surface. Recent work has determined that the width of solar wind-damaged rims on anorthite and olivine, and their respective SEP track densities are correlated with each other and with grain surface exposure age. Core sample 73002, recently released under the Apollo Next Generation Sample Analysis (ANGSA) Program, has provided an opportunity to study material collected from the light mantle formation in the Taurus-Littrow Valley during Apollo 17. The light mantle is thought to have been deposited vial and slide originating from the neighboring South Massif. Spectral analysis of bulk core soils found a plagioclase rich composition, confirming a highlands origin of the formation. Spectral profiles and ferromagnetic resonance (FMR) measurements of bulk soils sampled at cm-intervals from 73002 indicate that regolith up to~9.5 cm in depth have maturity indices consistent with longer durations of surface processing than samples deeper in the core. Thus, this upper ~9 cm layer likely represents the maximum extent of an in-situ reworking zone which may have persisted over 5 to 17million years. Here we present an analysis of grain exposure ages within the in-situ reworking zone of 73002derived from SEP track density measurements via transmission electron microscopy.

J A McFadden↗
NASA NTRS2024

Terrestrial Ages and Pairing of Howardites, Eucrites and Diogenites From the Miller Range Icefields, Antarctica

In the past 45 years, the US Antarctic Meteorite (ANSMET) program has recovered more than 22,000 meteorites from more than 50 individual meteorite stranding areas. Although the Antarctic meteorite collection is dominated by ordinary chondrites which represent 80-90% of the recovered samples, it also contains many achondrites, including howardites, eucrites and diogenites, which are collectively known as HED meteorites. A challenge for the Antarctic meteorite collection is to identify paired fragments that belong to the same fall. Eight ANSMET field sea-sons at the Miller Range Icefields (MIL), a series of blue ice fields about 40 km long and 10-20 km wide, have yielded more than 3000 meteorites including 56 HEDs. At least three possible pairing groups (with 3-10 members each) were initially identified among the MIL diogenites and one each among the howardites and eucrites. Since many HED meteorites are heterogeneous breccias, pairing identifications based on cm-sized samples is difficult and other independent evidence is needed to verify these proposed pairings, as was shown for several Antarctic howardite pairing-groups. Here we re-examine pairings of HED’s from the Miller Range Icefields, using multiple lines of evidence, including texture/petrography, chemical composition, cosmogenic radionuclides and find locations. Due to the heterogeneous nature of HED meteorites, we will not only consider pairings strictly among the three HED groups, but will also consider pairing of howardites with brecciated eucrites or brecciated diogenites if the cosmogenic nuclides, texture and chemical compositions support this. The concentrations of cosmogenic radionuclides in meteorites are a function of the cosmic-ray exposure (CRE) age, shielding conditions (size and irradiation depth), chemical composition, as well the terrestrial age of the meteorite sample. Since the production rates of cosmogenic nuclides as a function of meteoroid size, depth and composition are well understood [6], their measured concentrations can be used to determine which meteorites belong to the same fall even if the chemical composition of the samples show significant variations. We selected 28 of the 56 HED samples from the MIL collection, including 12 diogenites, 8 howardites and 8 brecciated eucrites to investigate pairing relationships.

howardite↗
NASA NTRS2024

Constraining the Surface Exposure Age of Asteroid Bennu Using Cosmogenic Radionuclides in an OSIRIS-REx Aggregate Sample and Individual Particles

Observations by NASA’s OSIRIS-REx spacecraft of asteroid Bennu revealed evidence that this small rubble-pile asteroid experiences several active surface processes that likely control its recent surface exposure history. In October 2020, the spacecraft collected a surface sample from a relatively young ~20 m diameter crater (Hokioi) on asteroid Bennu, and the sample was successfully delivered to Earth on September 24, 2023. Based on the population of craters >50 m diameter, Bennu’s surface is 0.1–1 Ga old, but the old surface is affected by recent processes including smaller meteoroid impacts, mass movement, and particle ejections. The sampling location within Hokioi crater was selected based on its relatively flat surface devoid of large boulders, but the crater floor is also believed to be one of the youngest surfaces on asteroid Bennu, with an age of <100 kyr. As the crater is ~2 m deep, the samples that were collected by OSIRIS-REx may have been relatively shielded from cosmic rays during most of its recent history. This scenario is different from the samples that were collected by Hayabusa2 from asteroid Ryugu, where cosmogenic noble gas and radionuclides indicate cosmic-ray exposure (CRE) ages of ~5 Myr near the surface. Our goal is to understand the recent exposure history of surface samples of asteroid Bennu utilizing radionuclides ( 10 Be, 26 Al, 36 Cl, 41 Ca) produced by both galactic (GCR) and solar (SCR) cosmic rays. With half- lives ranging from 0.1 to 1.36 million years (Myr), the concentrations of these cosmogenic nuclides provide information on the duration and exposure conditions (irradiation depth) of these samples on a timescale of a few Myr. This work will test one of the OSIRIS-REx mission’s driving hypotheses about asteroid Bennu’s recent evolution: that Hokioi crater is part of a population of small (25 m) spectrally red craters on Bennu that are less than 0.1 Myr old.

K. C. Welten↗
NASA NTRS2024

Preliminary Measurements of Partial Discharge Inception Voltage Degradation with Constant Temperature Aging of Magnet Wire Twisted Pairs for Electric Aircraft Motors

Electric aircraft require high reliability electric motors to meet the stringent safety standards of the aviation industry. Motor winding insulation lifetime and reliability models for electric aircraft applications are needed to enable design of high reliability and high-performance electric motors for aviation applications. Three primary stresses effect the lifetime of motor winding insulation: thermochemical, mechanical, and electrical. This paper presents preliminary experiments on twisted pairs of magnet wire targeting understanding the thermo-chemical degradation of motor winding insulation through constant temperature thermal aging. Three types of magnet wire twisted pairs where tested: polyimide insulated magnet wire, epoxy coated polyimide insulated magnet wire, and epoxy potted polyimide magnet wire. The degradation of the samples over time at temperature was tracked using partial discharge inception voltage measurements. These initial experiments were used for development of procedures and expertise in partial discharge testing and thermo-chemical aging to inform future testing. The preliminary nature of these experiments should be noted when viewing the results. Lessons learned from the experiments are documented.

Thomas Tallerico↗
NASA NTRSDate not supplied

Elastic-Poroelastic Simulation of Locally Resonant Ultrasound for Aging Li-Metal Batteries

An elastic-poroelastic simulation of ultrasound inspection for lithium-metal batteries is presented and compared to empirical reflection spectra measured during battery cycling. Simulated reflection spectra were obtained using a two-dimensional (2D) plane strain model, comprised of dozens of individual microns-thick layers within a Li-metal pouch cell. The simulated reflection spectra were then compared to ultrasonic reflection spectra measurements taken intermittently during cell cycling. A sensitivity analysis and parameter calibration were performed for the pristine pouch cell simulation prior to cycling, providing a baseline to account for difficult to measure poroelastic material parameters. Then, the reduction in solid Li anode thickness and corresponding growth into a mossy lithium layer was modeled to represent aging conditions. Results from both simulations and empirical inspections show similar trends in through-thickness resonance frequencies due to cell aging.

Battery↗
NASA NTRS1999

Aging and space flight: findings from the University of Pittsburgh

For more than a decade, the Sleep and Chronobiology Center (SCC) at the University of Pittsburgh has received funding from the National Institute on Aging (NIA), the National Institute of Mental Health (NIMH) and the National Aeronautics and Space Administration (NASA) in order to study the sleep and circadian rhythms of healthy older people, as well as the sleep and circadian rhythms of astronauts and cosmonauts. We have always been struck by the strong synergism between the two endeavors. What happens to the sleep and circadian rhythms of people removed from the terrestrial time cues of Earth is in many ways similar to what happens to people who are advancing in years. Most obviously, sleep is shorter and sleep depth is reduced, but there are also more subtle similarities between the two situations, both in circadian rhythms and in sleep, and in the adaptive strategies needed to enhance 24h zeitgebers.

STS-78 Shuttle Project↗
NASA NTRS1999

Age, splanchnic vasoconstriction, and heat stress during tilting

During upright tilting, blood is translocated to the dependent veins of the legs and compensatory circulatory adjustments are necessary to maintain arterial pressure. For examination of the effect of age on these responses, seven young (23 +/- 1 yr) and seven older (70 +/- 3 yr) men were head-up tilted to 60 degrees in a thermoneutral condition and during passive heating with water-perfused suits. Measurements included heart rate (HR), cardiac output (Qc; acetylene rebreathing technique), central venous pressure (CVP), blood pressures, forearm blood flow (venous occlusion plethysmography), splanchnic and renal blood flows (indocyanine green and p-aminohippurate clearance), and esophageal and mean skin temperatures. In response to tilting in the thermoneutral condition, CVP and stroke volume decreased to a greater extent in the young men, but HR increased more, such that the fall in Qc was similar between the two groups in the upright posture. The rise in splanchnic vascular resistance (SVR) was greater in the older men, but the young men increased forearm vascular resistance (FVR) to a greater extent than the older men. The fall in Qc during combined heat stress and tilting was greater in the young compared with older men. Only four of the young men versus six of the older men were able to finish the second tilt without becoming presyncopal. In summary, the older men relied on a greater increase in SVR to compensate for a reduced ability to constrict the skin and muscle circulations (as determined by changes in FVR) during head-up tilting.

NASA Discipline Cardiopulmonary↗
NASA NTRS1998

Age alters the cardiovascular response to direct passive heating

During direct passive heating in young men, a dramatic increase in skin blood flow is achieved by a rise in cardiac output (Qc) and redistribution of flow from the splanchnic and renal vascular beds. To examine the effect of age on these responses, seven young (Y; 23 +/- 1 yr) and seven older (O; 70 +/- 3 yr) men were passively heated with water-perfused suits to their individual limit of thermal tolerance. Measurements included heart rate (HR), Qc (by acetylene rebreathing), central venous pressure (via peripherally inserted central catheter), blood pressures (by brachial auscultation), skin blood flow (from increases in forearm blood flow by venous occlusion plethysmography), splanchnic blood flow (by indocyanine green clearance), renal blood flow (by p-aminohippurate clearance), and esophageal and mean skin temperatures. Qc was significantly lower in the older than in the young men (11.1 +/- 0.7 and 7.4 +/- 0.2 l/min in Y and O, respectively, at the limit of thermal tolerance; P < 0. 05), despite similar increases in esophageal and mean skin temperatures and time to reach the limit of thermal tolerance. A lower stroke volume (99 +/- 7 and 68 +/- 4 ml/beat in Y and O, respectively, P < 0.05), most likely due to an attenuated increase in inotropic function during heating, was the primary factor for the lower Qc observed in the older men. Increases in HR were similar in the young and older men; however, when expressed as a percentage of maximal HR, the older men relied on a greater proportion of their chronotropic reserve to obtain the same HR response (62 +/- 3 and 75 +/- 4% maximal HR in Y and O, respectively, P < 0.05). Furthermore, the older men redistributed less blood flow from the combined splanchnic and renal circulations at the limit of thermal tolerance (960 +/- 80 and 720 +/- 100 ml/min in Y and O, respectively, P < 0. 05). As a result of these combined attenuated responses, the older men had a significantly lower increase in total blood flow directed to the skin.

Clinical Trial↗