Search NASA⌕ Search

SEARCH · Search NASA

Results for “sample activation”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Factors Influencing Scanning for Alerts

Aircraft pilots (like operators in many domains) are required to monitor locations for rare events, while concurrently performing their everyday tasks. In many cases, the visual parameters of the alert are such that it is not visible unless directly fixated. For this reason, critical alerts should be designed to be visible in peripheral vision and/or augmented by an audio alarm. We use the term "conspicuity" to distinguish the attention-getting power of a visual stimulus from simple visibility in a single-task context. We have measured conspicuity in an experimental paradigm designed to test the N-SEEV model of attention and noticing (Steelman-Allen et al., HFES 2009). The subject performed a demanding central task while monitoring four peripheral locations for color change events. Visibility of the alerting stimuli was measured separately in a control experiment in which the subject maintained steady fixation without the central task. Thresholds in the dual-task experiments were lower than would be expected based on the results of the control experiment, due to the fact that the subjects actively sampled the alert locations with fixations while performing the central task. Locations of high-frequency alerts are generally sampled more often than locations of low-frequency alerts, and alert location sampling in general increases with practice, presumably because the demands of the central task are reduced.

Mulligan, Jeffrey B.↗
NASA NTRS2014

LADEE UVS Observations of Atoms and Dust in the Lunar Tail

The Lunar Atmosphere and Dust Environment Explorer (LADEE) was a lunar orbiter launched in September 2013 that investigated the composition and temporal variation of the tenuous lunar exosphere and dust environment. A major goal of the mission was to characterize the dust exosphere prior to future lunar exploration activities, which may alter the lunar environment. The Ultraviolet/Visible Spectrometer (UVS) onboard LADEE addresses this goal, utilizing two sets of optics: a limbviewing telescope, and a solar-viewing telescope. We report on spectroscopic (approximately 280 - 820 nm) observations viewing down the lunar wake or along the 'lunar tail' from lunar orbit. Prior groundbased studies have observed the emission from neutral sodium atoms extended along the lunar tail, so often this region is referred to as the lunar sodium tail. UVS measurements were made on the dark side of the moon, with the UVS limb-viewing telescope pointed outward in the direction of the Moon's wake (almost anti-sun), during different lunar phases. These UVS observation activities sample a long column and allow the characterization of scattered light from dust and emission lines from atoms in the lunar tail. Observations in this UVS configuration show the largest excess of scattered blue light in our data set, indicative of the presence of small dust grains in the tail. Once lofted, nanoparticles may become charged and picked up by the solar wind, similar to the phenomena witnessed above Enceladus's northern hemisphere or by the STEREO/WAVES instrument while close to Earth's orbit. The UVS data show that small dust grains as well as atoms become entrained in the lunar tail.

Dust and Solar Wind↗
NASA NTRS2019

Myco-Architecture off Planet: Growing Surface Structures at Destination

Our work focused on filling major select key technical knowledge gaps, and technical aspects to be addressed in a Phase II proposal were identified such as the secretion of glues or plastics by the fungi or bacteria to form biocomposites. Specifically, we raised the technical TRL by assessing the growth of in-house mycelial-producing strains on potential food substrates and analyzed the advantages and disadvantages to their use off planet. Growth of the mycelia on sawdust and powdered nutrients including dried, powdered algae, was used as a baseline. We measured growth as a function of temperature, tested the relevant material properties of the mycelia products produced, and measured the mass of input and output volume for production per volume of material. Mycotecture was produced in a bag simulating the proposed mission implementation. Post-production such as heat treatment (as is done with terrestrial mycotecture)was assessed.The material properties of the dried, frozen and baked mycelial outputs included density, strength,thermal insulation and flame retardation. Tensile/compression testing on biocomposite material specimens was performed to obtain three-dimensional elastic constants, as well as to examine deformation and fracture behavior. These mechanical tests were performed on both dormant and activated samples to understand the evolution of the structural material. In addition, experimental data obtained from the mechanical testing was used to build a failure prediction model that accounts for material anisotropy. This aided in future structural design through a quantitative understanding of the mechanical limits of the material. To examine the texture, defects, fracture surfaces of the material, high-resolution microstructural imaging was utilized before and after the mechanical tests. This microstructural analysis informed us about the macro-structural behavior and influenced structural design. Thermal decomposition analysis was also performed tounderstand the thermal limits.

Biocomposites↗
NASA NTRSDate not supplied

Three Years of Airborne Observations During NASA Activate: A Statistical Summary of Chemical, Optical, and Microphysical Aerosol Properties Over the Western North Atlantic Ocean

Airborne observations are critical to understanding Earth’s climate system and surface-level air quality by providing both spatial and vertical information that is not possible through ground measurement networks or satellite observations. Airborne platforms allow assessments of long-range transport, vertical redistribution, boundary-layer dynamics, and cloud-aerosol-interactions that are critical to model evaluation and satellite validation. Still, the high cost and effort of aircraft operations can limit measurement campaigns to short, focused time periods. Multiple deployments are often necessary for seasonal comparisons, and results can be limited if target phenomenon are infrequent. Subsequent analyses typically focus on case studies, especially if deployment conditions are climatologically anomalous. The NASA ACTIVATE (Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment) mission was designed to overcome these limitations by operating semi-continuously over multiple months during multiple seasons. Flight plans were intentionally simple, repetitive, and systematic to provide a statistically robust dataset that could be utilized similarly to a ground-network. Here, we present an overview of three years (2020-2022) of aerosol measurements from the NASA HU-25 Falcon aircraft supporting the ACTIVATE mission. Data from 179 flights were considered, the majority of which were based at NASA Langley Research Center and flown locally over the Wester North Atlantic Ocean just east of Hampton, VA, USA. Airmass characteristics tended to transition from continental outflow near the coast to mostly marine over the open ocean. Seasonal, diurnal, spatial, and vertical trends in aerosol microphysical, optical, and chemical properties are discussed in the context of synoptic scale meteorology. Statistical benefits of the ACTIVATE sampling strategy are discussed with regard to future model evaluation.

Luke D Ziemba↗
DOE OSTI2013

IN-LINE CHEMICAL SENSOR DEPLOYMENT IN A TRITIUM PLANT

The Savannah River Tritium Plant (TP) relies on well understood but aging sensor technology for process gas analysis. Though new sensor technologies have been brought to various readiness levels, the TP has been reluctant to install technologies that have not been tested in tritium service. This gap between sensor technology development and incorporating new technologies into practical applications demonstrates fundamental challenges that exist when transitioning from status quo to state-of-the-art in an extreme environment such as a tritium plant. These challenges stem from three root obstacles: 1) The need for a comprehensive assessment of process sensing needs and requirements; 2) The lack of a pick-list of process-compatible sensor technologies; and 3) The need to test technologies in a tritium-contaminated process environment without risking production. At Savannah River, these issues are being addressed in a two phase project. In the first phase, TP sensing requirements were determined by a team of process experts. Meanwhile, Savannah River National Laboratory sensor experts identified candidate technologies and related them to the TP processing requirements. The resulting roadmap links the candidate technologies to actual plant needs. To provide accurate assessments of how a candidate sensor technology would perform in a contaminated process environment, an instrument demonstration station was established within a TP glove box. This station was fabricated to TP process requirements and designed to handle high activity samples. The combination of roadmap and demonstration station provides the following assets: Creates a partnership between the process engineers and researchers for sensor selection, maturation, and insertion, Selects the right sensors for process conditions Provides a means for safely inserting new sensor technology into the process without risking production, and Provides a means to evaluate off normal occurrences where and when they occur. This paper discusses the process to identify and demonstrate new sensor technologies for the Savannah River TP.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2015

Overview of the conceptual design of the future VENUS beamline at the Spallation Neutron Source

VENUS will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to m). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beamline 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS

instrument design↗
DOE OSTI2021

Detector Calibration to Quantify Random Summing in HPGe Spectroscopy

While calibrating a High Purity Germanium (HPGe) Radiation Detector for Xenon-133 (133Xe) the process of random summing occurs which leads to excess counts in the 160.6keV peak from random summing of the 81keV photons at the 162keV energy. Multiple samples of 133Xe with varying levels of radioactivity were assayed to determine a relationship between the occurrence of random summing and the net area of the 160.6keV peak. When the calculated efficiencies in the 160.6keV peak were compared to the theoretical efficiency obtained from a multi-energy calibration at 160.6keV, the amount of random summing could be estimated as excess observed efficiency and correlated to the sample activity. While a trend is apparent in the data, the mechanisms that contribute to the trend are still being studied so the data can be accurately correlated.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2013

A Single Tower Configuration of the Modular Gamma Box Counter System - 13392

Canberra's Standard Gamma Box Counter System is designed to perform accurate quantitative assays of gamma emitting nuclides for a wide range of large containers including B-25 crates and ISO shipping containers. Using a modular building-block approach, the system offers tremendous flexibility for a variety of measurement situations with wide ranges of sample activities and throughput requirements, as well as the opportunity to modify the configuration for other applications at a later date. The typical configuration consists of two opposing towers each equipped with two high purity germanium detectors, and an automated container trolley. This paper presents a modified configuration, consisting of a single tower placed inside a measurement trailer with three detector assemblies, allowing for additional vertical segmentation as well as a viewing a container outside the trailer through the trailer wall. An automatic liquid nitrogen fill system is supplied for each of the detectors. The use of a forklift to move the container for horizontal segmentation is accommodated by creating an additional operational and calibration set-up in the NDA 2000 software to allow for the operator to rotate the container and assay the opposite side, achieving the same sensitivity as a comparable two-tower system. This Segmented Gamma Box Counter System retains the core technologies and design features of the standard configuration. The detector assemblies are shielded to minimize interference from environmental and plant background, and are collimated to provide segmentation of the container. The assembly positions can also be modified in height and distance from the container. The ISOCS calibration software provides for a flexible approach to providing the calibrations for a variety of measurement geometries. The NDA 2000 software provides seamless operation with the current configuration, handling the data acquisition and analysis. In this paper, an overview of this system is discussed, along with the measured performance results, calibration methodology and verification, and minimum detectable activity levels. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

Recent Advancements in Tomographic Gamma Scanning for Non- Destructive Assay - 17321

Canberra Industries has recently designed and built a Tomographic Gamma Scanning (TGS) system for the deployment in a nuclear facility. The TGS technique combines high-resolution gamma spectroscopy with low spatial resolution 3- dimensional image reconstruction to provide increased accuracy over traditional approaches for the assay of non-uniform source distributions in low-to medium-density containers. The TGS system has been optimized to measure 120 liter drums and has the capability to measure containers of various sizes. Canberra has incorporated numerous enhancements and improvements to the latest system in both its hardware and software components. The signal processing chain and data analysis software have been configured to use either an electronic pulser or digital signal processing (DSP) electronics for dead time corrections. In the case of using the DSP electronics, the need to calibrate and maintain a pulser can be eliminated without sacrificing any performance. For the 120 liter container, the TGS system has been calibrated and validated with three different spatial resolutions, using two collimator aperture sizes, measuring 2.54 and 1.27 cm in width. The system has also been supplied and calibrated with a wide, rectangular collimator (25.4 cm W x 10.2 cm H) for scanning containers solely in the vertical axis. The TGS system also has an automated attenuator assembly, which has the capability to use a combination of attenuators to reduce the count rate for high activity samples. An extensive measurement campaign was performed in addition to the calibration verification to evaluate the accuracy of the system using rod sources, point sources, and a variety of matrices and source distributions. Improvements to the evaluation of the total measurement uncertainty based upon these studies have been incorporated into the analysis software package. Finally, the performance of this new TGS system will be demonstrated in the context of Canberra's previous TGS systems, including several 208 liter-based systems and a smaller, 20 liter container TGS system. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2012

MID- AND FAR-INFRARED PROPERTIES OF A COMPLETE SAMPLE OF LOCAL ACTIVE GALACTIC NUCLEI

We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly complete sample of local active galactic nuclei (AGNs) detected in the Swift/Burst Alert Telescope (BAT) all-sky hard X-ray (14-195 keV) survey, based on the cross correlation with the AKARI infrared survey catalogs complemented by those with Infrared Astronomical Satellite and Wide-field Infrared Survey Explorer. Out of 135 non-blazer AGNs in the Swift/BAT nine-month catalog, we obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22, and/or 25 {mu}m band. We find good correlation between their hard X-ray and MIR luminosities over three orders of magnitude (42 < log {lambda}L{sub {lambda}}(9, 18 {mu}m) < 45), which is tighter than that with the FIR luminosities at 90 {mu}m. This suggests that thermal emission from hot dusts irradiated by the AGN emission dominate the MIR fluxes. Both X-ray unabsorbed and absorbed AGNs follow the same correlation, implying isotropic infrared emission, as expected in clumpy dust tori rather than homogeneous ones. We find excess signals around 9 {mu}m in the averaged infrared spectral energy distribution from heavy obscured 'new type' AGNs with small scattering fractions in the X-ray spectra. This could be attributed to the polycyclic aromatic hydrocarbon emission feature, suggesting that their host galaxies have strong starburst activities.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRSDate not supplied

ISS External Microorganisms: Collecting Planetary Protection Samples During Extravehicular Activity

We have developed, tested, and flown a caddy capable of collecting aseptic samples from external surfaces of the ISS (International Space Station). The sampling caddy is certified for use during US EVA (extra vehicular activity) and was launched to ISS in the summer of 2023. We are scheduled to collect samples from 6 locations outside ISS during an EVA in May of 2024. We will freeze these samples at -80°C on orbit and return them to Earth. We will then extract and sequence any DNA collected during the EVA using next generation sequencing technologies to characterize the community composition and function of each sample. Measuring the type and quantity of microbes present on the exterior of ISS will allow us to address knowledge gap 2B, “Acceptable levels of microbial/organic releases from humans and support systems” described in a 2019 COSPAR report. Collecting data about microbial release from current crewed vehicles will inform requirements for acceptable leak rates for future crewed missions to Mars. The sampling kit consists of eight commercially available, sterile, DNA free, macrofoam swabs ( 23 mm. diameter ) installed in custom aluminum end effectors. Each end effector is housed in and individual aluminum canister. Each canister contains a 0.2 μm Teflon filter to allow the interior volume to accommodate pressure changes without permitting microbial contaminants to enter the sterile interior volume. A handle repurposed from the space shuttle tile repair kit is used to remove the end effector from the sample canister, collect a sample by swabbing a surface and then replace the end effector in its canister. The canisters and end effectors were cleaned and assembled on Earth. Prior to installing the sterile swab the canisters and end effectors were sterilized in an autoclave at 134°C, 215 kPA, for 7 min.. The final assembly occurred in a sterilized class II biosafety cabinet. We will collect six samples from the 1) airlock vestibule, 2) airlock thermal cover, 3) a gap in the micrometeorite shielding near the airlock, 4) a handrail near the airlock, 5) the CDRA (Carbon Dioxide Removal Assembly) vent, and 6) the VES (Vacuum Exhaust System) vent. The remaining two swabs will be reserved as controls. One swab will be exposed during the EVA without touching any surfaces to act as a blank. The final swab will remain sealed until the entire sampling kit is returned to earth. Based on previously published results from the Russian segment, we hypothesize that there will be detectable microbes at some or all of these locations. Ground-based testing of this sampling caddy confirms that the swabs remain sterile as the canisters transition in and out of vacuum. We were able to retrieve, viable bacterial and fungal cells as well as DNA from samples collected from US space suits during vacuum chamber tests lasting as long as seven hours. Based on these results and feedback from the test subjects the sampling caddy was modified to improve ergonomics and meet US EVA safety requirements. Bayonet probes were added to the sides of the sample kit as alternate mounting points. Additional locking features were added to the end effector and the filter stack to prevent inadvertent release during use. The opening mechanism was changed from one where the end effector was rocked laterally to defeat a ball detent to a twist-to-open threaded closure for similar reasons. Demonstrating, this sampling caddy’s effectiveness during a US EVA will allow us to address knowledge gaps identified in COSPAR reports and begin to define planetary protection requirements for life support systems on crewed missions to mars. This kit could also be used to collect contamination control samples during Artemis missions to verify requirements and could be easily modified for robotic sample collection.

Planetary Protection↗
NASA NTRS1974

Nondestructive activation analysis of sample of lunar surface material returned by Luna 16 automatic station

The composition of a sample of lunar surface material returned by the Luna 16 automatic station from the Sea of Fertility was studied, using nondestructive activation analysis. The structure of the returned surface material is inhomogeneous; the surficial material is thin, quite homogeneous, and the granularity increases with depth. Based on grain size, the sample was separated into five zones. The activation analysis was conducted on a sample taken from the friable surficial layer, zone A. The content of Al, Mn, Na, Cr, Co, Fe, and Sc was determined by nondestructive activation analysis of the sample. In determining Cr, Co, Fe, and Sc, the sample was irradiated for 24 hours and cooled for 10 days. Gamma spectra of the samples were recorded with a semiconductor Ge(Li)-detector and a multichannel analyzer, and measurement data were processed with an electronic computer.

Chayko, M.↗
DOE OSTI2017

Activation product analysis in a mixed sample containing both fission and neutron activation products

Activation analysis of gold (Au) is used to estimate neutron fluence resulting from a criticality event; however, such analyses are complicated by simultaneous production of other gamma-emitting fission products. Confidence in neutron fluence estimates can be increased by quantifying additional activation products such as platinum (Pt), tantalum (Ta), and tungsten (W). This work describes a radiochemical separation procedure for the determination of these activation products. Anion exchange chromatography is used to separate anionic forms of these metals in a nitric acid matrix; thiourea is used to isolate the Au and Pt fraction, followed by removal of the Ta fraction using hydrogen peroxide. W, which is not retained on the first anion exchange column, is transposed to an HCl/HF matrix to enhance retention on a second anion exchange column and finally eluted using HNO3/HF. Chemical separations result in a reduction in the minimum detectable activity by a factor of 287, 207, 141, and 471 for 182Ta, 187W, 197Pt, and 198Au respectively, with greater than 90% recovery for all elements. These results represent the highest recoveries and lowest minimum detectable activities for 182Ta, 187W, 197Pt, and 198Au from mixed fission-activation product samples to date, enabling considerable refinement in the measurement uncertainties for neutron fluences in highly complex sample matrices.

anion exchange↗
DOE OSTI2016

Brady's Geothermal Field Nodal Seismometer Active Source Data Sample

This data is in sac format and includes recordings of two active source events from 238 three-component nodal seismometers deployed at Bradys Hot Springs geothermal field as part of the PoroTomo project. The source was a viberoseis truck operating in P-wave vibrational mode and generating a swept-frequency signal. The files are 33 seconds long starting 4 seconds before each sweep was initiated. There is some overlap in the file times.

15 GEOTHERMAL ENERGY↗
DOE OSTI2018

Impala: A Flexible Adaptive Sampling Algorithm for Active Learning

The Implicit Potential Active Learning Algorithm, or impala, is a novel approach to adaptive sampling that allows for the blending of multiple independent query strategies into a common batch active learning framework. This methodology is agnostic to both the underlying learning model and the employed query strategies. In essence, impala treats query strategies as potential functions, which are combined into a probability of candidate selection. The end result is a flexible algorithm that can dynamically balance exploration and exploitation whose inherent variability guards against over-zealous greedy searching.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

Nitrogen concentration and isotope dataset for environmental samples from 2012 and 2013, Barrow, Alaska

Dataset includes nitrate concentrations for polygonal active layer samples and snowmelt; ammonium concentrations for active layer samples; nitrate isotopes for active layer samples, snowmelt, and permafrost; ammonium isotopes for active layer samples; and nitrogen isotopes for soils and dissolved organic nitrogen extracted from soil pore waters. This dataset contains 2 csv files and 1 pdf.The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research.The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska.Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Herschel far-infrared photometry of the swift burst alert telescope active galactic nuclei sample of the local universe. I. PACS observations

Far-Infrared (FIR) photometry from the Photodetector Array Camera and Spectrometer on the Herschel Space Observatory is presented for 313 nearby, hard X-ray selected galaxies from the 58 month Swift Burst Alert Telescope (BAT) Active Galactic Nuclei catalog. The present data do not distinguish between the FIR luminosity distributions at 70 and 160 μm for Seyfert 1 and Seyfert 2 galaxies. This result suggests that if the FIR emission is from the nuclear obscuring material surrounding the accretion disk, then it emits isotropically, independent of orientation. Alternatively, a significant fraction of the 70 and 160 μm luminosity could be from star formation, independent of active galactic nucleus (AGN) type. Using a non-parametric test for partial correlation with censored data, we find a statistically significant correlation between the AGN intrinsic power (in the 14-195 keV band) and the FIR emission at 70 and 160 μm for Seyfert 1 galaxies. We find no correlation between the 14-195 keV and FIR luminosities in Seyfert 2 galaxies. The observed correlations suggest two possible scenarios: (1) if we assume that the FIR luminosity is a good tracer of star formation, then there is a connection between star formation and the AGN at sub-kiloparsec scales, or (2) dust heated by the AGN has a statistically significant contribution to the FIR emission. Using a Spearman rank-order analysis, the 14-195 keV luminosities for the Seyfert 1 and 2 galaxies are weakly statistically correlated with the F {sub 70}/F {sub 160} ratios.

79 ASTRONOMY AND ASTROPHYSICS↗