SEARCH · Engineering Papers

Results for “site detection”

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.

SourceResearch connectionFrom yearThrough year

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

At least 1,063 records · Page 59

All sources NASA NTRS DOE OSTI

DOE OSTI2026

Synthesis of ARM User Facility Surface Rainfall Datasets to Construct a Best Estimate Value Added Product (PrecipBE)

Surface precipitation measurements are essential for Earth system model (ESM) evaluation and understanding cloud processes. An ever-growing need for robust, temporally evolving, and easy-to-use statistical datasets provides motivation for a baseline ground-based precipitation properties data product. The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility operates an extensive suite of precipitation instruments with various sensitivities and operating mechanisms, which render the decision of which instrument to use based on one or more fixed thresholds challenging and prone to errors and bias. Using a long-term instrument inter-comparison from a unique per-precipitation event perspective, rather than instantaneous sample comparison, we demonstrate that ARM rainfall-measuring instruments are generally consistent with each other at the statistical level. Inter-instrument deviations at the single event level can be large, especially for specific rainfall event properties such as maximum precipitation rates. A machine-learning (ML) analysis using a random forest regressor indicates that in some cases, depending on instrument, local site climatology, and/or specific deployment configuration, certain atmospheric state variables influence the measured quantities in an unpredictable manner. Thus, a-priori weighting of different instruments does not necessarily lead to more accurate and less biased synthesis of instrument data. These results motivate the design of the ARM precipitation best-estimate (PrecipBE) value-added product, which incorporates all valid precipitation data while considering data quality and other instrument limitations. PrecipBE consists of time series and tabular statistics datasets in an easy-to-use and insightful per-precipitation event format. It provides a large set of precipitation event properties supplemented with ancillary data from ARM datasets that correspond to the detected precipitation events. We describe the PrecipBE algorithm and demonstrate its use via the examination of a single-day output as well as a long-term trend analysis of precipitation events at the ARM Southern Great Plains (SGP) site, covering more than 30 years of data. The trend analysis tentatively suggests a long-term temporal tendency for mainly shorter and less intense precipitation events at the SGP site, but a long-term increase in annual rainfall by more than 36 mm (5 %) per decade. This rainfall trend is catalyzed primarily by more extreme event properties of relatively rare, intense precipitation events, with event total and 1 min maximum precipitation rate at a 1 year timeframe increasing up to 5 mm and 9 mm h −1 (several percent) per decade, respectively. While the currently available PrecipBE datasets (at https://adc.arm.gov/discovery/, last access: 8 December 2025) cover rainfall from multiple ARM deployments up to March 2025, PrecipBE is planned to be expanded to include solid-phase precipitation and will soon become an operational product with a several-day lag from real-time. We invite the ARM user community to leverage this new product and welcome user feedback to further enhance the dataset.

Silber, Israel [Pacific Northwest National Laborat↗

NASA NTRS2024

A Physics-Based Antarctic Melt Detection Technique: Combining Advanced Microwave Scanning Radiometer 2, Radiative-Transfer Modeling, and Firn Modeling

Surface melt on ice shelves has been linked to hydrofracture and subsequent ice shelf breakup. Since the 1990s, scientists have been using microwave radiometers to detect melt on ice shelves and ice sheets by applying various statistical thresholding techniques to identify significant increases in brightness temperature that are associated with melt. In this study, instead of using a fixed threshold, we force the Snow Radiative Transfer model (SMRT) with outputs from the Community Firn Model (CFM) to create a dynamic, physics-based threshold for melt. In the process, we also combine our method with statistical thresholding techniques and produce microwave grain size information in the process. We run this “Hybrid Method” across the Larsen C ice shelf as well as thirteen sites on the Antarctic Ice Sheet. Melt and non-melt days from the Hybrid Method and three statistical thresholding techniques match with surface energy balance within 94±1%; the effect of melt on the passive microwave is mostly binary and thus largely detectable by statistical thresholding techniques as well as physics-based techniques. Rather than always replacing statistical thresholding techniques with the Hybrid Method, we recommend using the Hybrid Method in studies where melt volume or grain size is of interest. In this study, we show that the Hybrid Method can be used to (a) model dry snow brightness temperatures of Antarctic snow and (b) derive a measure of grain size; therefore, it is an important step forwards towards using firn and radiative transfer modeling to quantify melt rather than to simply detect melt days.

Marissa E Dattler↗

NASA NTRS2000

Modern Microbial Ecosystems are a Key to Understanding Our Biosphere's Early Evolution and its Contributions To The Atmosphere and Rock Record

The survival of our early biosphere depended upon efficient coordination anion- diverse microbial populations. Microbial mats exhibit a 3.46-billion-year fossil record, thus they are the oldest known ecosystems. Photosynthetic microbial mats were key because, today, sunlight powers more than 99 percent of global primary productivity. Thus photosynthetic ecosystems have affected the atmosphere profoundly and have created the most pervasive, easily-detected fossils. Photosynthetic biospheres elsewhere will be most detectible via telescopes or spacecraft. As a part of the Astrobiology Institute, our Ames Microbial Ecosystems group examines the roles played by ecological processes in the early evolution of our biosphere, as recorded in geologic fossils and in the macromolecules of living cells: (1) We are defining the microbial mat microenvironment, which was an important milieu for early evolution. (2) We are comparing mats in contrasting environments to discern strategies of adaptation and diversification, traits that were key for long-term survival. (3) We have selected sites that mimic key environmental attributes of early Earth and thereby focus upon evolutionary adaptations to long-term changes in the global environment. (4) Our studies of gas exchange contribute to better estimates of biogenic gases in Earth's early atmosphere. This group therefore directly addresses the question: How have the Earth and its biosphere influenced each other over time Our studies strengthen the systematics for interpreting the microbial fossil record and thereby enhance astrobiological studies of martian samples. Our models of biogenic gas emissions will enhance models of atmospheres that might be detected on inhabited extrasolar planets. This work therefore also addresses the question: How can other biospheres be recogniZed" Our choice of field sites helps us explore Earth's evolving early environment. For example, modern mats that occupy thermal springs and certain freshwater environments experience conditions such as low O2 and sulfate and high inorganic carbon and sulfide levels that resemble those of ancient marine environments. Later in history, both biologically-induced carbonate precipitation and the trapping and binding of suspended grains of carbonate became a dominant mechanism for carbonate deposition. Modern marine carbonate platforms and alkaline offer good examples of microbiologically-induced calcification. Both marine platforms and solar salterns illustrate microbially-driven trapping and binding. We are also exploring the effects of water composition upon the exchange of biogenic gases with the atmosphere.

DesMarais, David J.↗

NASA NTRS2025

VIPER’s Mass Spectrometer observing lunar operations (MSolo)

The Volatiles Investigating Polar Exploration Rover (VIPER) is a lunar volatiles detection and measurement mission that will land on Mons Mouton near Nobile crater, close to the Moon’s south pole. One of the analytical instruments embedded within the rover is the Mass Spectrometer observing lunar operations (MSolo) instrument. VIPER’s data will ultimately be used to create lunar water resource maps that may enable a sustained presence on the lunar surface. As VIPER navigates several kilometers of terrain, its onboard analytical instrumentation will characterize the presence of volatiles along the traverse path and identify candidate locations for drilling. Upon selection of a drilling site, the rover will position itself and deploy an auguring, percussive drill down to a meter depth. Upon extraction, regolith cuttings captured by the auger are deposited on the surface; an activity that will initiate the release of any volatile gases that are subsequently detected and quantified by MSolo. MSolo is designed to identify low-molecular-weight volatiles (between m/z 1-100) with unit mass resolution. Volatiles of interest include D/H and O18/O16 bearing species, including possible water contained within the lunar regolith. MSolo is a modified, commercial off-the-shelf (COTS) system, meaning the instrument is based on a commercially available unit that has been ruggedized for space applications.

MSolo↗

DOE OSTI2025

Miscanthus × giganteus increases soil maximum water holding capacity compared to maize

Soil ecosystem services, like the ability to store water, have been depleted after a century of conventional, annual cropping, and perennial crops offer a solution to this and other agricultural environmental issues. We assessed the impact of Miscanthus × giganteus (miscanthus), a perennial biomass crop, on soil water holding capacity and structure compared to continuous maize (Zea mays L.) at two sites in Iowa. After three growing seasons, we measured the following: (1) maximum water holding capacity (MWHC) with and without soil structure, and (2) total porosity and pore size distribution (PSD) via micro-computed tomography (microCT). Miscanthus increased MWHC by 14.7% across both sites relative to maize (p = 0.002), and we attributed this to structural changes due to the lack of a crop effect when measured on structureless soils. No significant changes were detected in soil organic matter, texture, total porosity, or PSD that could explain the increase in MWHC under miscanthus. Our findings suggest that the increases in MWHC are primarily due to structural changes rather than increases in soil organic matter or porosity (at least porosity detectable by microCT). This study highlights miscanthus' potential to enhance soil water storage and underscores the need for further investigation to clarify the mechanisms through which this biomass crop influences soil structural properties.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2024

Self-Assembled Bolaamphiphile-Based Organic Nanotubes as Efficient Cu(II) Ion Adsorbents

Self-assembled organic nanotubes (ONTs) have been actively examined for various applications such as chemical separations and catalysis owing to their well-defined tubular nanostructures with distinct chemical environments at the wall and internal/external surfaces. Adsorption of heavy metal ions onto ONTs plays an essential role in many of these applications, but it has rarely been assessed quantitatively. Herein, we investigated interactions between Cu 2+ and single-/quadruple-wall bolaamphiphile-based ONTs having inner carboxyl groups with different inner diameters, COOH-ONT 10nm and COOH-ONT 20nm . We first examined the effects of Cu 2+ on their nanotubular structures using SAXS, STEM, and AFM. COOH-ONT 10nm was stable in aqueous Cu 2+ solution in contrast to COOH-ONT 20nm owing to the presence of polyglycine-II-type hydrogen bonding networks within its wall. Subsequently, we studied the Cu 2+ adsorption behavior of COOH-ONT 10nm by monitoring the concentration of unbound Cu 2+ using linear sweep anodic stripping voltammetry. The Cu 2+ adsorption was quick, attributable to efficient Cu 2+ partitioning through the open ends of the ONT, followed by fast Cu 2+ diffusion in the uniform, relatively large nanochannel. More importantly, the Cu 2+ adsorption capacity and affinity of COOH-ONT 10nm were measured at different pH using the Langmuir adsorption model. The adsorption capacity was similar at the pH range examined, showing the participation of approximately 25% of the inner carboxyl groups in the adsorption. The adsorption affinity increased with pH, indicating the essential role of the deprotonated carboxyl groups in the Cu 2+ adsorption. Most interestingly, the Langmuir adsorption constant was significantly higher than those of previously reported synthetic adsorbents and planar monolayer based on carboxyl binding sites. The high Cu 2+ affinity of the ONT was attributable to the highly dense binding sites on the well-defined nanoscale concave structure of the inner channel. Furthermore, these results provide a valuable guideline to designing self-assembled nanomaterials for efficient chemical separations, detection, and catalysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2025

Widespread underestimation of rain-induced soil carbon emissions from global drylands

Dryland carbon fluxes, particularly those driven by ecosystem respiration, are highly sensitive to water availability and rain pulses. However, the magnitude of rain-induced carbon emissions remains unclear globally. Here we quantify the impact of rain-pulse events on the carbon balance of global drylands and characterize their spatiotemporal controls. Using eddy-covariance observations of carbon, water and energy fluxes from 34 dryland sites worldwide, we produce an inventory of over 1,800 manually identified rain-induced CO2 pulse events. Based on this inventory, a machine learning algorithm is developed to automatically detect rain-induced CO2 pulse events. Our findings show that existing partitioning methods underestimate ecosystem respiration and photosynthesis by up to 30% during rain-pulse events, which annually contribute 16.9 ± 2.8% of ecosystem respiration and 9.6 ± 2.2% of net ecosystem productivity. We show that the carbon loss intensity correlates most strongly with annual productivity, aridity and soil pH. Finally, we identify a universal decay rate of rain-induced CO2 pulses and use it to bias-correct respiration estimates. Our research highlights the importance of rain-induced carbon emissions for the carbon balance of global drylands and suggests that ecosystem models may largely underrepresent the influence of rain pulses on the carbon cycle of drylands.

Nguyen, Ngoc B↗

DOE OSTI2021

Soil Sampling Results for Closure of a Portion of Solid Waste Management Unit #16

The U.S. Department of Energy/National Nuclear Security Administration (DOE/ NNSA) and National Technology & Engineering Solutions of Sandia, LLC (NTESS), the management and operating contractor for Sandia National Laboratories/California (SNL/CA), has prepared this soil sampling results report for closure of a portion of Solid Waste Management Unit (SWMU) #16. The entire network of SNL/CA sanitary sewer lines, including building laterals, was identified as SWMU #16 under a Resource Conservation and Recovery Act (RCRA) Facility Assessment conducted for SNL/CA in April 1991 (DOE 1992). Along with the previous SWMU #16 investigation results (SNL/CA 2019), the results of this investigation are intended to support closure decisions by the San Francisco Bay Regional Water Quality Control Board (RWQCB), as discussed below. SNL/CA personnel completed upgrading its sanitary sewer discharge network in 2019. These upgrades included installing new sections of underground lines and decommissioning certain sections of the old piping system by capping in place. To date, several sections of the sewer line have been abandoned-in-place by capping as new sewer lines were installed or flow was rerouted to other existing lines. To formally close these abandoned sections of the sewer line, the RWQCB required that SNL/CA personnel collect soil samples to be analyzed for contaminants potentially released from the sewer lines. SNL/CA personnel hired Weiss Associates (Weiss) of Emeryville, California to prepare a sampling and analysis plan, implement the sampling plan and report the results of the investigation under Purchase Order #2166257. The Sampling and Analysis Plan for Partial Closure of Solid Waste Management Unit #16 (SAP) was submitted to the RWQCB on August 14, 2020 by Weiss on behalf of SNL/CA. The RWQCB approved the SAP on September 30, 2020 after Weiss updated the method detection limit and reporting limits for total polychlorinated biphenyls (PCBs) and individual aroclors. Soil sampling was conducted in accordance with the SAP except that fewer locations were sampled due to site constraints, as discussed below. This report presents the results of the sampling effort and documents all associated field activities including borehole clearing, soil sample collection, storage and transportation to the analytical laboratories, borehole backfilling and surface restoration, and storage of investigation-derived waste (IDW) for future profiling and disposal by SNL/CA waste management personnel.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2022

Understanding the Seismic Ground Motion Spatial Variability Using Network Analysis Community Detection

This project is to explore ground motion spatial distribution using a new approach graph-based network analysis. In this study, we combine a large-N seismic array and graph analytics to explore spatial variability and correlation at a local scale using small local and regional earthquakes. In this method, each seismic station is modeled as a node and the similarities of the waveforms that represent ground motions between two stations are modeled as edges. By analyzing this graph network using the similarity matrices and community detection algorithm, we can group the stations spatially with similar patterns. A random forest algorithm is used to reveal the important features that affect the spatial grouping. The result suggests site conditions, and how they interact with the incident seismic wavefield, strongly condition the spatial correlation of ground motion. Future progress in characterizing ground motion spatial variability will require dense wavefield measurements, either through nodal deployments, or perhaps distributed acoustic sensing measurements of seismic wavefields.

58 GEOSCIENCES↗

DOE OSTI2026

Particulate Effluent Characterization (Final Report)

Understanding particulate emissions from nuclear facilities could help differentiate between normal nuclear operations and potential nuclear accidents or nuclear weapons tests. Oak Ridge National Laboratory (ORNL) is unique in that there are several types of nuclear facilities on site: an operating production reactor, radiochemical separation facilities, and a spallation neutron source. This project deployed a high-volume particulate air filter sampler to collect airborne particulate effluent from the nuclear facilities on site at ORNL. Collections occurred regularly from November 1, 2024, through June 30, 2025, and were analyzed via gamma spectroscopy in the laboratory. The radioisotope iodine-123 ( 123 I) was detected in several samples throughout the collection period. Detailed atmospheric transport modeling was performed on all detections for source attribution, and the most likely source of the 123 I was determined to be the Spallation Neutron Source. The project demonstrated the viability of ORNL as a test bed for effluent monitoring studies.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1977

Integration of remote sensing and surface geophysics in the detection of faults

Remote sensing was included in a comprehensive investigation of the use of geophysical techniques to aid in underground mine placement. The primary objective was to detect faults and slumping, features which, due to structural weakness and excess water, cause construction difficulties and safety hazards in mine construction. Preliminary geologic reconnaissance was performed on a potential site for an underground oil shale mine in the Piceance Creek Basin of Colorado. LANDSAT data, black and white aerial photography and 3 cm radar imagery were obtained. LANDSAT data were primarily used in optical imagery and digital tape forms, both of which were analyzed and enhanced by computer techniques. The aerial photography and radar data offered supplemental information. Surface linears in the test area were located and mapped principally from LANDSAT data. A specific, relatively wide, linear pointed directly toward the test site, but did not extend into it. Density slicing, ratioing, and edge enhancement of the LANDSAT data all indicated the existence of this linear. Radar imagery marginally confirmed the linear, while aerial photography did not confirm it.

Jackson, P. L.↗

NASA NTRS1990

Lidar and aircraft studies of deep Cirrus systems from the 1986 FIRE IFO

Several NCAR King Air flight missions were conducted during the Wisconsin FIRE IFO experiment in support of the University of Utah polarization lidar observations of deep cirrus cloud systems at the Wausau ground site. Data collected from four cirrus systems are included in this analysis, including those of 22 and 28 October, and 1 and 2 November. Lidar data were generally obtained at 2 min intervals in the zenith direction over observation periods that ranged from approximately 4 to 10 h, bracketing the aircraft missions. The data were processed to yield height-time (HTI) displays of lidar linear depolarization ratio sigma and relative range-normalized return power P. King Air operations consisted of a combination of rapid profiling and Lagrangian spiral descents and stacked racetrack patterns in the vicinity of the field site. From the spiral descents are constructed vertical profiles of ice particle concentration N(sub i) and ice mass content IWC derived from PMS 2-D probe imagery and, when detected, FSSP cloud droplet concentration N(sub W) and liquid water content, LWC. Aircraft flight leg data are presented for the vertical velocity W and the same ice and water cloud content parameters. In addition, aerosol particle concentrations obtained with the ASAS probe are examined, and photographs of ice particles collected in-situ on oil-coated slides are presented to illustrate ice particle habit.

Sassen, Kenneth↗

NASA NTRS1992

Space debris measurement program at Phillips Laboratory

Ground-based optical sensing was identified as a technique for measuring space debris complementary to radar in the critical debris size range of 1 to 10 cm. The Phillips Laboratory is building a staring optical sensor for space debris measurement and considering search and track optical measurement at additional sites. The staring sensor is implemented in collaboration with Wright Laboratory using the 2.5 m telescope at Wright Patterson AFB, Dayton, Ohio. The search and track sensor is designed to detect and track orbital debris in tasked orbits. A progress report and a discussion of sensor performance and search and track strategies will be given.

Dao, Phan D.↗

NASA NTRS1992

Nucleotide-Protectable Labeling of Sulfhydryl Groups in Subunit I of the ATPhase from Halobacterium Saccharovorum

A membrane-bound ATPase from the archaebacterium Halobacterium saccharovorum is inhibited by N-ethyl-maleimide in a nucleotide-protectable manner. When the enzyme was incubated with N-[C-14]jethylmaleimide, the bulk of radioactivity was as- sociated with the 87,000-Da subunit (subunit 1). ATP, ADP, or AMP reduced incorporation of the inhibitor. No charge shift of subunit I was detected following labeling with N-ethylmaleimide, indicating an electroneutral reaction. The results are consistent with the selective modification of sulfhydryl groups in subunit I at or near the catalytic site and are further evidence of a resemblance between this archaebacterial ATPase and the vacuolar-type ATPases.

Sulzner, Michael↗

NASA NTRS2021

Breakdown and Self-healing in Tantalum Capacitors

Reliability of tantalum capacitors depends on the efficiency of self-healing that restores parts after breakdown. In this work, different types of polymer and MnO2 cathode capacitors have been tested for scintillation breakdown using a constant current stress (CCS) technique modified to allow detection of amplitudes and duration of current spikes. Monitoring of leakage currents with time under bias is used to assess the effect of scintillations. The appearance and composition of damaged sites have been examined after deprocessing and cross-sectioning. Thermal processes during scintillations have been analyzed, a mechanism of breakdown based on growth of conductive filaments in the dielectric suggested, and self-healing processes in polymer and MnO2 cathode capacitors discussed.

tantalum capacitor↗

NASA NTRS2022

Going to Extremes: Architecting Holographic Microscopes for Extreme Environments

Bacterial life exists on earth in extreme environments. These are environments described by large temperature excur- sions, large pressure excursions, and large radiation excursions from the nominal conditions near sea level which are largely populated by humans. These extreme locales represent such places as the ocean ice, the briny pools of Death Valley and deep mines, the acidic hot springs of the High Sierra or Yellowstone, or even the clouds of our upper atmosphere. The preponderance of bacterial life in these extreme environments here on earth suggests that bacterial life might likely exist in the extreme environments of our own solar system, such as the icy moons of Europa or Enceladus. Thus, architecting instruments for detect- ing life in these extreme environments on earth builds confidence that we can architect such instruments for flight missions. In this paper, we discuss our experience with designing digital holo- graphic microscope instruments to enable detection of bacteria in several extreme environments. In particular we discuss three different instruments. The first is our field instrument which is a small, portable instrument for examination of remote sites. The second is submersible instrument which enables exploration of deep aquatic environments and is deployed on a ocean-going drone. The third is a balloon-borne instrument to examine the bacterial content of the upper atmosphere. We will provide a review of each instrument and discuss aspects of instrument engineering for each particular application.

Ramirez, Alex↗

NASA NTRS1974

Soil moisture detection by Skylab's microwave sensors

The author has identified the following significant results. Terrain microwave backscatter and emission response to soil moisture variations were investigated using Skylab's 13.9 GHz RADSCAT (radiometer/scatterometer) system. Data acquired on June 5, 1973, over a test site in west-central Texas indicated a fair degree of correlation with composite rainfall. The scan made was cross-track contiguous (CTC) with a pitch of 29.4 deg and no roll effect. Vertical polarization was employed with both radiometer and scatterometer. The composite rainfall was computed according to the flood prediction technique using rainfall data supplied by weather reporting stations.

Moore, R. K.↗

DOE OSTI2025

Non-destructive identification of absorptive damage sites by photoluminescence brightening

We present a non-destructive photoluminescence (PL) imaging strategy for probing damage growth behavior in fused silica under laser irradiation. Transient wide-field PL image measurements were conducted at varying excitation intensities to investigate the dynamics of radiative defect generation and annihilation in laser-induced damage sites. Our results reveal that, while low excitation intensities predominantly induce PL quenching due to defect annihilation, high-intensity excitation (>0.3 GW/cm 2 at 532 nm) triggers pronounced PL brightening (PLB), indicative of radiative defect generation. Image analysis demonstrates that PLB events are strongly correlated with subsequent damage growth (10 J/cm 2 at 351 nm), whereas overall PL intensity is not. No optically detectable morphological changes were observed during PLB, confirming the non-destructive nature of the technique. We propose that PLB arises from defect-assisted absorption of multiple photons at pre-existing absorptive centers, which enhances local absorptivity and initiates further defect formation. These findings establish PLB monitoring as a sensitive diagnostic tool for identifying damage sites with elevated absorptivity, enabling targeted maintenance and improved laser damage management in optical materials.

Materials science↗