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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.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Porous Colloidal Nanoparticles as Injectable Multimodal Contrast Agents for Enhanced Geophysical Sensing

Injecting fluids into underground geologic structures is crucial for the development of long-term strategies for managing captured carbon and facilitating sustainable energy extraction operations. Here, we have previously reported that the injection of metal–organic frameworks (MOFs) into the subsurface can enhance seismic monitoring tools to track fluids and map complex structures, reduce risk, and verify containment in carbon storage reservoirs because of their absorption capacity of low-frequency seismic waves. Here, we demonstrate that water-based Cr/Zn/Zr MOF colloidal suspensions (nanofluids) are multimodal geophysical contrast agents that enhance near-wellbore logging tools. Based on experimental fluid-only measurements, MIL-101(Cr), ZIF-8, and UiO-66 nanofluids have distinct complex conductivity and/or low-field nuclear magnetic resonance (NMR) signatures that are relevant to field-deployed technologies, implying the potential to enhance near-wellbore monitoring of CO 2 injection and associated processes with downhole logging tools. Small- and wide-angle X-ray scattering characterization of ~0.5 wt % MIL-101(Cr) suspensions confirmed phase stability and provided insight into the fractal nature of colloidal nanoparticles. Finally, low-field (2 MHz) NMR measurements of MIL-101(Cr) nanofluid injection into a prototypical Berea sandstone demonstrate how paramagnetic high-surface area MOFs may dominate the relaxation times of hydrogen-bearing fluids in porous geologic matrices, enhancing the mapping of near-surface and near-wellbore transport pathways and advancing sustainable subsurface energy technologies.

NMR↗
DOE OSTI2019

Remote sensing and geophysical characterization of a floodplain-hillslope system in the East River watershed, Colorado

This package is part of the Watershed Function SFA Data Collection and contains remote sensing data and geophysical measurements acquired at the Pumphouse hillslope-floodplain site, in the East River, Colorado. The remote sensing dataset includes: a) a WorldView-2 (WV-2) pan-sharpened multi-spectral remote sensing image, and b) LiDAR derived products. The WV-2 image was acquired on September 24th, 2015, and it is composed of eight spectral bands (coastal, blue, green, yellow, red, red edge, NIR1, and NIR2) with a spatial resolution of 0.5 m, covering an area of 750x750 m. The LiDAR products are a digital surface model (DSM), representing the top-of-canopy elevation, and a digital terrain model (DTM), representing the bare-ground elevation, at the spatial resolution of 0.5 m. Such data are extracted from the LiDAR point-cloud dataset acquired over the entire watershed on August 2015 (http://dx.doi.org/10.21952/WTR/1412542). The geophysical dataset is composed of the electrical resistivity tomography (ERT) data acquired along a 158.75 m long transect, spanning the hillslope topographical gradient with 1.25 m electrode spacing. The dataset also includes soil water content measured with a TDR system. The package provides also polygons of different vegetation communities, which were used as reference data for mapping plant community distributions. The spatial polygons are based on plant locations acquired during the field campaign of June-July 2017 using an RTK DGPS system. The reference dataset is composed by 11 vegetation classes, namely, deciduous forest, evergreen forest, riparian shrubland, sagebrush, shrubland, potentilla, frasera, lupine meadow, veratrum, bunchgrass meadow, and forb, as well as four non-vegetation classes, such as water-river, water-lake, man-made, bare area, and shadow. The vegetation classes are determined based on distinct spectral and/or structural signatures of dominant species. The package includes products derived by these datasets, such as: a) a plant height map, computed by subtracting the DTM from the DSM, and b) a plant community distribution map, obtained by using a data-fusion machine-learning-based framework that exploit the WV-2 image and plant height information.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

The Importance of Accounting for Landscape Position When Investigating Grasslands: A Multidisciplinary Characterisation of a California Coastal Grassland

Abstract Grasslands are one of the most common land‐cover types, providing important ecosystem services globally, yet few studies have examined grassland critical‐zone functioning throughout hillslopes. This study characterised a coastal grassland over a small hillslope at Point Reyes National Seashore, California, using multidisciplinary techniques, combining remotely‐sensed, geophysical, plant, and soil measurements. Clustering techniques delineated the study area into four landscape zones, up‐, mid‐, and down‐slope, and a bordering riparian ecotone, which had distinct environmental properties that varied spatially across the site, with depth, and time. Soil moisture increased with depth and down slope towards a bordering riparian zone, and co‐varied with soil CO 2 flux rates both spatially and temporally. This highlighted three distinct controls of soil moisture on soil respiration: CO 2 fluxes were inhibited by high moisture content in the down‐slope during the wet winter months, and converged across landscape positions in the dry summer months, while also displaying post‐rain pulses. The normalised difference vegetation index (NDVI) ranged from 0.32 (September)–0.80 (April) and correlated positively with soil moisture and aboveground biomass, moving down slope. Yet, NDVI, aboveground biomass, and soil moisture were not correlated to soil organic carbon (SOC) content (0.4%–4.5%), which was highest in the mid‐slope. The SOC content may instead be linked to shifts in dominant grassland species and their rhizosphere properties with landscape position. This multidisciplinary characterisation highlighted significant heterogeneity in grassland properties with landscape position, and demonstrated an approach that could be used to characterise other critical‐zone environments on hillslopes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

The SMART Cables Initiative for Ocean and Geophysical Observing [Slides]

SMART Cables are becoming a reality, and have the potential to revolutionize submarine oceanographic and geophysical sensing. Pilot / demonstration projects are underway to test the technology and explore the feasibility of incorporating both in-repeater standardized sensor packets but also ancillary sensor types on external, branching nodes. The projects currently in planning will set the standard and influence the norms for the future of SMART systems. The interest of all potential stakeholders and users, and input as to needs and concerns, is welcomed as testing proceeds.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Investigating Microtopographic and Soil Controls on a Mountainous Meadow Plant Community Using High-Resolution Remote Sensing and Surface Geophysical Data

Our study aims to explore the microtopographic controls that dictate the heterogeneity of plant communities in a mountainous floodplain-hillslope system, using remote sensing and surface geophysical techniques. Working within a lower montane floodplain-hillslope study site (750 m × 750 m) in the Upper Colorado River Basin, we developed a new data fusion framework, based on machine learning and feature engineering, that exploits remote sensing optical and light detection and ranging (LiDAR) data to estimate the distribution of key plant meadow communities at submeter resolution. We collected surface electrical resistivity tomography data to explore the variability in soil properties along a floodplain-hillslope transect at 0.50-m resolution and extracted LiDAR-derived metrics to model the rapid change in microtopography. Furthermore, we investigated the covariability among the estimated plant community distributions, soil information, and topographic metrics. Results show that our framework estimated the distribution of nine plant communities with higher accuracy (87% versus 80% overall; 85% versus 60% for shrubs) compared to conventional classification approaches. Analysis of the covariabilities reveals a strong correlation between plant community distribution, soil electric conductivity, and slope, indicating that soil moisture is a primary control on heterogeneous spatial distribution. At the same time, microtopography plays an important role in creating particular ecosystem niches for some of the communities. Such relationships could be exploited to provide information about the spatial variability of soil properties. This highly transferable framework can be employed within long-term monitoring to capture community-specific physiological responses to perturbations, offering the possibility of bridging local plot-scale observations with large landscape monitoring.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

From Grain to Floodplain: Evaluating heterogeneity of floodplain hydrostatigraphy using sedimentology, geophysics, and remote sensing

Stratigraphy is a fundamental component of floodplain heterogeneity and hydraulic conductivity and connectivity of alluvial aquifers, which affect hydrologic processes such as groundwater flow and hyporheic exchange. Watershed–scale hydrological models commonly simplify the sedimentology and stratigraphy of floodplains, neglecting natural floodplain heterogeneity and anisotropy. This study, conducted in the upper reach of the East River in the East River Basin, Colorado, USA, combines point–, meander–, and floodplain–scale data to determine key features of alluvial aquifers important for estimating hydrologic processes. We compare stratigraphy of two meanders with disparate geometries to explore floodplain heterogeneity and connectivity controls on flow and transport. Meander shape, orientation, and internal stratigraphy affected residence time estimates of laterally exchanged hyporheic water. Although the two meanders share a sediment source, vegetation, and climate, their divergent river migration histories resulted in contrasting meander hydrofacies. In turn, the extent and orientation of these elements controlled the effective hydraulic conductivity and, ultimately, estimates of groundwater transport and hyporheic residence times. Additionally, the meanders’ orientation relative to the valley gradient impacted the hydraulic gradient across the meanders—a key control of groundwater velocity. In conclusion, we combine our field data with remotely sensed data and introduce a potential approach to estimate key hydrostratigraphic packages across floodplains. Prospective applications include contaminant transport studies, hyporheic models, and watershed models.

58 GEOSCIENCES↗
DOE OSTI2017

Introduction to this special section: Geophysical applications of fiber-optic distributed sensing

Here, this special section is dedicated to geophysical distributed acoustic sensing (DAS) and distributed temperature sensing (DTS) applications. Since the introduction of commercial DTS units in the 1980s and more recent deployment of DAS in this decade, distributed sensing is quietly revolutionizing sectors of geophysics, particularly those requiring permanent downhole measurements. The common component of distributed sensing technologies is the use of laser scattering measurements on fiber-optic cables (tens of kilometers long) to estimate the physical state of each fiber segment with measurands including temperature (DTS), static strain (DSS), and, most recently, dynamic strain and seismic waves (DAS) recorded either continuously or on an as-needed basis. The high spatial coverage, accuracy, and resolution of this technology make it a truly groundbreaking addition to our subsurface sensing toolbox.

47 OTHER INSTRUMENTATION↗
DOE OSTI2013

Quantifying and relating land-surface and subsurface variability in permafrost environments using lidar and surface geophsical datasets

The complexity of permafrost dynamics and its critical impact on climate feedbacks warrant continued development of advanced high-latitude terrestrial ecosystem characterization and monitoring approaches. In this study, we explore the value of remote sensing and surface geophysical data for characterizing land surface and subsurface properties and their linkages in an Alaskan Coastal Plain ecosystem. We base our study on data collected at the end of the 2011 growing season in the Barrow Environmental Observatory, where a nested suite of measurements were collected within a polygon-dominated region including: surface ground penetrating radar, electromagnetic, and electrical resistance tomography data; thaw depth, soil temperature and moisture content, soil texture, soil carbon and nitrogen content, and major and trace cations. Previously-collected lidar data were also available for the study. Analysis of the datasets, individually and in combination, revealed the utility of the methods for characterizing critical land-surface and subsurface properties and associated spatial zonation. Lidar analysis was performed to extract geomorphic metrics (such as slope, curvature, and directed distance of polygons), which potentially indicate drainage potential and permafrost deformation state. Cluster analysis of these lidar-obtained attributes suggested that the land surface can be grouped into three spatially coherent zones, each having a dominant geomorphic expression including: a high centered polygon zone, a low centered polygon zone and a transitional zone. Comparison of the geophysical attributes from radar, electrical resistance tomography, and electromagnetic data with point measurements suggests that the surface geophysical data can provide very high-resolution information about subsurface properties that affect ecosystem feedbacks to climate, such as thaw depth and moisture content. Cluster analysis suggested that the geophysical attributes also varied spatially in a systematic way, suggesting the presence of three laterally distinct subsurface zones. Analysis of zone-based subsurface point measurements suggests that the geophysically-defined zones have unique distributions of hydrological, thermal, and geochemical properties and that the subsurface (geophysically-based) and land-surface (lidar-based) zonation is consistent. Although the close linkage between land surface (polygonal geomorphology) and subsurface (active layer) variability revealed through our study is not surprising, to our knowledge this is the first study to document such relationships using high resolution and non-invasive approaches. This study suggests the potential of using coincident lidar and surface geophysical measurements to quantify land surface and subsurface properties (respectively) and their linkages, which are likely to play a role in terrestrial ecosystem evolution and feedbacks to climate. These findings open the way for future research focused on using combined geophysical and remote sensing datasets to estimate subsurface and land-surface properties in high resolution and over large regions as is needed for process understanding and numerical model initialization in high latitude terrestrial ecosystems.

Climate↗
DOE OSTI2015

Expanding Geothermal Resource Utilization through Directed Research, Education, and Public Outreach

The Great Basin Center for Geothermal Energy (GBCGE or the Center) was established at the University of Nevada, Reno (UNR) in May 2000 to promote research and utilization of geothermal resources. The Center received funding through this grant to promote increased geothermal development in the Great Basin, with most of the funding used for peer-reviewed research. Funding to the Center and work under the contract were initiated in March 2002, with supplemental funding in subsequent years. The Center monitored the research projects that were competitively awarded in a series of proposal calls between 2002 and 2007. Peer-reviewed research promoted identification and utilization of geothermal resources in Nevada. Projects used geology, geochemistry, geophysics, remote sensing, and the synthesis of multi-disciplinary information to produce new models of geothermal systems in the Western U.S. and worldwide. Funds were also used to support graduate student research and training. Part of the grant was used to support public outreach activities, including webpages, online maps and data resources, and informational workshops for stakeholders.

15 GEOTHERMAL ENERGY↗
DOE OSTI2010

Semi autonomous mine detection system

CMMAD is a risk reduction effort for the AMDS program. As part of CMMAD, multiple instances of semi autonomous robotic mine detection systems were created. Each instance consists of a robotic vehicle equipped with sensors required for navigation and marking, a countermine sensors and a number of integrated software packages which provide for real time processing of the countermine sensor data as well as integrated control of the robotic vehicle, the sensor actuator and the sensor. These systems were used to investigate critical interest functions (CIF) related to countermine robotic systems. To address the autonomy CIF, the INL developed RIK was extended to allow for interaction with a mine sensor processing code (MSPC). In limited field testing this system performed well in detecting, marking and avoiding both AT and AP mines. Based on the results of the CMMAD investigation we conclude that autonomous robotic mine detection is feasible. In addition, CMMAD contributed critical technical advances with regard to sensing, data processing and sensor manipulation, which will advance the performance of future fieldable systems. As a result, no substantial technical barriers exist which preclude – from an autonomous robotic perspective – the rapid development and deployment of fieldable systems.

42 ENGINEERING↗
DOE OSTI2019

Sampling Density in Regional Exploration and Environmental Geochemical Studies: A Review

A variety of factors contribute to the proper and efficient evaluation of geochemical programs including sampling medium, sample size and sample fraction, sampling density, digestion procedure, and analytical techniques. Among the aforementioned factors, sampling density is of great importance, affecting project ability to detect anomalous sites, which are either economically viable or environmentally hazardous. It is quite critical to have a sufficient number of samples to delineate geochemical anomalies or baselines and to reveal the relative variations in elemental concentrations in a study area. The resolution of the subsequent maps obtained by sampling greatly depends on sampling density. While a large number of samples may generate redundant data, a small number of samples smooth out the patterns and may completely miss anomalies. This review provides a platform for applied geochemists who desire to design a sampling scheme for a regional geochemical program and do not have the financial resources to perform an orientation survey, which will give them the necessary information for designing, according to project objectives, a cost-effective regional geochemical survey for their study area. It is advisable to integrate during the desktop study all available information, such as geological, structural, geophysical, remote sensing data and topographical data by using different data fusion algorithms to arrive at a sampling density fit-for-purpose of the target area. This in turn facilitates an effective spatial positioning of sample locations. Quantitative analyses of the efficiency of different sampling densities for delineating geochemical patterns have not been well documented, warranting more attention and research.

58 GEOSCIENCES↗
DOE OSTI2023

Finite-difference time-domain methods

The finite-difference time-domain (FDTD) method is a widespread numerical tool for full-wave analysis of electromagnetic fields in complex media and for detailed geometries. Applications of the FDTD method cover a range of time and spatial scales, extending from subatomic to galactic lengths and from classical to quantum physics. Technology areas that benefit from the FDTD method include biomedicine — bioimaging, biophotonics, bioelectronics and biosensors; geophysics — remote sensing, communications, space weather hazards and geolocation; metamaterials — sub-wavelength focusing lenses, electromagnetic cloaks and continuously scanning leaky-wave antennas; optics — diffractive optical elements, photonic bandgap structures, photonic crystal waveguides and ring-resonator devices; plasmonics — plasmonic waveguides and antennas; and quantum applications — quantum devices and quantum radar. This Primer summarizes the main features of the FDTD method, along with key extensions that enable accurate solutions to be obtained for different research questions. Additionally, hardware considerations are discussed, plus examples of how to extract magnitude and phase data, Brillouin diagrams and scattering parameters from the output of an FDTD model. Furthermore, the Primer ends with a discussion of ongoing challenges and opportunities to further enhance the FDTD method for current and future applications.

42 ENGINEERING↗
DOE OSTI2014

Convective overstability in radially stratified accretion disks under thermal relaxation

This paper expands the stability criterion for radially stratified, vertically unstratified accretion disks incorporating thermal relaxation. We find a linear amplification of epicyclic oscillations in these disks that depends on the effective cooling time, i.e., an overstability. The growth rates of the overstability vanish for both extreme cases, e.g., infinite cooling time and instantaneous cooling, i.e., the adiabatic and fully isothermal cases. However, for thermal relaxation times τ on the order of the orbital frequency, τΩ ∼ 1, modes grow at a rate proportional to the square of the Brunt-Väisälä frequency. The overstability is based on epicyclic motions, with the thermal relaxation causing gas to heat while radially displaced inward and cool while radially displaced outward. This causes the gas to have a lower density when moving outward compared to when it moves inward, so it feels the outward-directed pressure force more strongly on that leg of the journey. We suggest the term 'convective overstability' for the phenomenon which has already been studied numerically in the nonlinear regime in the context of amplifying vortices in disks under the name 'subcritical baroclinic instability'. The aim of the present paper is to make clear that vortex formation in three-dimensional disks is not necessarily subcritical, i.e., does not need a finite perturbation, nor is it baroclinic in the sense of geophysical fluid dynamics, which requires on vertical shear. We find that convective overstability is a linear instability that will operate under a wide range of physical conditions for circumstellar disks.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Aquifer recharge, depletion, and connectivity: Inferences from GRACE, land surface models, and geochemical and geophysical data

We used data from the Gravity Recovery and Climate Experiment (GRACE) and outputs of the CLM4.5 model to estimate recharge and depletion rates for large aquifers, investigate the connectivity of an aquifer's subbasins, and identify barriers and preferred pathways for groundwater flow within an aquifer system. The Nubian Sandstone Aquifer System and its subbasins (Dakhla, Northern Sudan Platform, and Kufra) in northeast Africa were used for demonstration purposes, and findings were tested and verified against geological, geophysical, remote sensing, geochronologic, and geochemical data. There are four major findings. (1) The average annual precipitation data over recharge areas in the southern Kufra section and the Northern Sudan Platform subbasin were estimated at 54.8 km 3 , and 32.8 km 3 , respectively, and knowing the annual extraction rates over these two areas (similar to 0.40 ± 0.20 km 3 ), recharge rates were estimated at 0.78 ± 0.49 km 3 /yr and 1.44 ± 0.42 km 3 /yr, respectively. (2) GRACEderived groundwater depletion rates over the Dakhla subbasin and the Northern Kufra section were estimated at 4.44 ± 0.42 km 3 /yr and 0.48 ± 0.32 km 3 /yr, respectively. (3) The observed depletion in the southern parts of the Dakhla subbasin is apparently caused by the presence of the east- west- trending Uweinat-Aswan basement uplift, which impedes the south-to-north groundwater flow and hence reduces replenishment from recharge areas in the south. (4) A major northeast- southwest- trending shear zone (Pelusium shear system) is apparently providing a preferred groundwater flow pathway from the Kufra to the Dakhla subbasin. Thus, inte-grated approach provides a replicable and cost-effective model for better understanding of the hydrogeologic setting of large aquifers worldwide and for optimum management of these groundwater resources.

58 GEOSCIENCES↗
DOE OSTI2016

Brady's Geothermal Field DAS Vibroseis Data

The submitted data correspond to the monitored vibrations caused by a vibroseis seismically exciting the ground in the vertical direction and captured by the DAS horizontal and vertical arrays during the PoroTomo Experiment. The data also include a file with the acceleration record at the Vibroseis. Vibroseis Sweep Details: Sweep on location T84 Stage 4 (Mode P 60 s long record ) Time: 2016-03-25 14:01:15 (UTC) Location: 39.80476089N, -119.0027625W Elevation: 1272.0M (on ground surface at the site) Sweep length: 20 seconds Frequencies: 5 Hz to 20 Hz

15 GEOTHERMAL ENERGY↗
DOE OSTI2018

DASH Slow Strain Rates from Brady Hot Springs Geothermal Field during PoroTomo Deployment Period

This submission contains slow strain rates summed to radians over 30 second intervals [rad/s] derived from horizontal distributed acoustic sensing measurements (DASH) of Brady geothermal field during PoroTomo deployment (2016-Mar-14 to 2016-Mar-26). There is one file corresponding to each day written in *.mat format for use with Matlab. The format for the binary Matlab .mat files are defined at: https://www.mathworks.com/help/pdf_doc/matlab/matfile_format.pdf. One such file includes the following variables: 'flist': list of raw DASH files used in the summation 'time_tag_mdt': sample time tag in datetime format with hours given in 24-hr format (yyyy/MM/dd HH:mm:ss.SSSSSSS) 'time_tag_uts': sample time tag in Unix time 'strain_rate_summed_over30s_in_radians_per_second': slow strain rates summed over 30 second intervals in units rad/s 'sample_standard_deviation_in_radians_per_second': corresponding sample standard deviation of slow strain rates in units rad/s The PoroTomo final technical report, raw DASH data, and software repository are also available through the links below.

15 GEOTHERMAL ENERGY↗