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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

University of California, San Diego (UCSD) Sky Imager Cloud Position Study Field Campaign Report

During the University of California, San Diego (UCSD) Sky Imager Cloud Position Study, two University of California, San Diego Sky Imagers (USI) (Figure 1) were deployed the U.S. Department of Energy(DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains SGP) research facility. The UCSD Sky Imagers were placed 1.7 km apart to allow for stereographic determination of the cloud height for clouds over approximately 1.5 km. Images with a 180-degree field of view were captured from both systems during daylight hours every 30 seconds beginning on March 11, 2013 and ending on November 4, 2013. The spatial resolution of the images was 1,748 × 1,748, and the intensity resolution was 16 bits using a high-dynamic-range capture process. The cameras use a fisheye lens, so the images are distorted following an equisolid angle projection.

58 GEOSCIENCES↗
DOE OSTI2017

Quantum Control of Spins in Diamond for Nanoscale Magnetic Sensing and Imaging

Our research activities during the grant period focused on the challenges of highly accurate and precise magnetometry and magnetic imaging using quantum spins inside diamond. Our work has resulted in 6 papers published in peer-reviewed journals, with two more currently under consideration by referees. We showed that through the use of novel phase estimation algorithms inspired by quantum information science we can carry out accurate and high dynamic range DC magnetometry as well as lock-in detection of oscillating (AC) magnetic fields. We investigated the geometric phase as a route to higher precision quantum information and magnetic sensing applications, and probed the experimental limits to the fidelity of such geometric phase gates. We also demonstrated that there is a spin dependent signal in the charge state flipping of the NV defect center in diamond, which could potentialy be useful for higher fidelity spin readout at room temperature. Some of these projects have now led to further investigation in our lab on multi-photon spectroscopy (manuscript in preparation), and plasmonic guiding of light in metal nanowires (manuscript available on arxiv). In addition, several invited talks were given by the PI, and conference presentations were given by the graduate students and postdocs.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Miniature CCD X-Ray Imaging Camera Technology Final Report CRADA No. TC-773-94

The goal of the project was to develop a compact, large active area, high spatial resolution, high dynamic range, charge-coupled device (CCD) camera to replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating X-rays. The camera head and controller needed to be capable of operation within a vacuum environment and small enough to be fielded within the small vacuum target chambers at LLNL.

42 ENGINEERING↗
DOE OSTI2019

Understanding the Response of Photosynthetic Metabolism in Tropical Forests to Seasonal Climate Variations

We propose a study focused on the basic question: What controls the response of photosynthesis in Amazonian forests to seasonal variations in climate? This question, despite its apparent simplicity, remains difficult for modern earth system models to answer, and is also the subject of continuing controversy in the remote-sensing literature. For example, in the modeling arena, four cutting-edge earth system models (ESM’s) show significant divergence in their seasonal patterns of photosynthesis from observed whole-system photosynthetic fluxes at two sites in the central Amazon. The overall objective of the project is to guide improvements in earth system models of tropical forest photosynthesis by collecting and integrating a suite of observations to 1) test several hypotheses (three core, conceptual hypotheses for explaining observed photosynthetic seasonality and a methodological hypotheses for scaling from leaves to canopy with hyperspectral cameras), and 2) perform a synthesis activity that applies our empirical work to earth system models of terrestrial carbon cycling. The project will provide an extensive suite of new and unique datasets that enable us to fill, through advanced modeling techniques and analysis, critical knowledge gaps in current understanding of what controls the response of canopy photosynthesis and related functions in Amazonian forests to seasonal variation in climate. Three major types of datasets and data products will be delivered: (1) in situ leaf and tree-scale measurements from intensive ecophysiological and ecohydological field campaigns, (2) time-series observations of leaf-to-crown scale forest reflectance properties and atmospheric radiation from two innovative, ground-based imaging sensors (respectively, the Hyperspectral Vegetation Imaging System and the High Dynamic Range All-Sky Imaging System), and (3) results from state-of-the-art models of 3-dimensional canopy processes for radiative transfer and photosynthesis that integrate and link our observations to tropical forest processes. These data products and the improved knowledge we achieve with them will contribute to testing and improving the treatment of tropical forest processes in ESMs. They will contribute data to and leverage related data from of the GOAmazon campaign, and make significant contributions to support the overall goals of GOAmazon. This work will also help establish a foundation for the Next Generation Ecosystem Experiments (NGEE) in the Tropics.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

2020 State of the Science Report, Chapter 8: Encounters of Marine Animals with Marine Renewable Energy Device Mooring Systems and Subsea Cables

Many marine renewable energy (MRE) technologies, including floating or midwater wave and tidal devices, require mooring systems (i.e., mooring lines and anchors) to maintain their position within the water column or on the sea surface. In the case of some devices such as tidal kites, these lines and cables can be highly dynamic. An array of non-bottom-mounted devices may also include transmission cables within the water column interconnecting devices to one another, or to offshore substations or hubs on the seabed. The potential for these lines and cables to present hazards for marine animals that may become entangled or entrapped in them, or confused by their presence remains an issue of uncertainty. The degree to which mitigation to avoid or reduce entanglement risk might be required for future MRE installations is yet to be determined, pending greater understanding of the actual nature of the risk. In this chapter, the entanglement or entrapment of a marine animal is defined as the cause to become caught in a system without possibility of escaping. https://tethys.pnnl.gov/publications/state-of-the-science-2020-chapter-8-moorings

16 TIDAL AND WAVE POWER↗
DOE OSTI2020

Spatiotemporal Analyses of Groundwater and Shoreline Cr(VI) Concentrations in the 100 Areas at Hanford

Cleanup efforts have been ongoing since the late 1990s to remediate contaminated waste sites and groundwater in the 100 Areas at the U.S. Department of Energy (DOE) Hanford Site. One of the primary contaminants of concern is hexavalent chromium (Cr(VI)), which was used as a corrosion inhibitor in cooling water for nuclear reactors that formerly operated along the shoreline of the Columbia River. Cleanup efforts have included 1) removal, treatment (as needed), and disposal of contaminated sediments; 2) in situ redox manipulation as a permeable reactive barrier; 3) pump-and-treat; 4) soil flushing; and 5) monitored natural attenuation. DOE’s annual groundwater monitoring reports document the significant reductions in Cr(VI) plume areas that have occurred over the past 10 years or more as a result of these cleanup efforts. The Record of Decision for the 100-HR-3 operable unit specified a cleanup level (CUL) for Cr(VI) in groundwater of 48 µg/L to protect human receptors, and a surface water CUL of 10 µg/L to protect aquatic organisms in the Columbia River. The Record of Decision did not specify point-of-compliance locations for the surface water CUL. Data for 2019 from the six groundwater operable units (OUs) in the 100 Areas indicate that the 48 μg/L groundwater CUL has been achieved in 100% of the wells in the 100-BC and 100-NR OUs, and in 89- 97% of the wells in the other OUs (100-KR, 100-HR-D, 100-HR-H, 100-FR). Data for 2019 indicate that 100% of the aquifer tubes monitored for Cr(VI) in the 100 Areas have concentrations below the 48 μg/L groundwater CUL. However, the 10 μg/L standard has not yet been consistently achieved for both inland groundwater monitoring wells and shoreline aquifer tubes. This report describes a series of data analyses performed to identify consistent relationships, if any, between inland well and shoreline Cr(VI) concentrations within the 100 Areas. To this end, select monitoring data for Cr(VI) measured in groundwater and aquifer tubes at the 100 Areas were analyzed for a 10-year period—2010 to 2019. Relationships between inland groundwater plumes and surface-water points of discharge in and along the Columbia River were examined through several analyses that included inland well and aquifer tube concentrations as a function of distance from the shoreline, evaluation of cumulative probability plots, trend analysis, correlation analysis, cluster analysis, and identification of plume trajectories for each of the 100 Areas. The analyses did not identify consistent relationships between inland groundwater Cr(VI) concentrations and shoreline concentrations within the 100 Areas due to several confounding factors influencing groundwater flow directions and Cr(VI) concentrations. The proximity of groundwater Cr(VI) plumes to the river, and the highly dynamic nature of the river, influence the transport behavior of the plumes and create challenges for quantifying attenuation of Cr(VI) between the inland monitoring wells and shoreline concentrations. Other factors contributing to temporal and spatial Cr(VI) concentrations, as supported by some of the data analyses, include the presence of vadose zone sources, variable sorption behavior, and complexities associated with Cr(VI) mass transfer between the upper and lower aquifers and their interactions with the river. Hence, monitoring to assess compliance with target CULs will need to be determined for each area individually since several factors influence Cr(VI) concentrations in the 100 Areas.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Collaborative Research: Explosive reconnection in relativistic magnetically-dominated plasmas (Final Report)

Magnetic fields can be the dominant component of astrophysical plasmas, so that the magnetic energy density might exceed even the rest-mass energy density of matter. In this extreme (and largely unexplored) regime the magnetic field controls the overall plasma evolution, dissipation, and acceleration of non-thermal particles. This plasma regime, applicable to a variety of astrophysical sources - magnetars, pulsars and pulsar wind nebulae (PWNe), jets of Active Galactic Nuclei (AGNs) and Gamma-Ray Bursters (GRBs) - is dramatically different from laboratory plasmas, the magnetospheres of planets, and the interplanetary plasma. Relativistic astrophysical sources then provide an unique opportunity to study the fundamental plasma physics of magnetically-dominated plasmas; a novel and fast-evolving field of theoretical research which, by investigating energy conversion and particle energization processes in plasmas, is of vital importance to the Fusion Energy Sciences DoE program. Data coming from astrophysical high-energy missions, especially the Crab Nebula flares recently observed by the Fermi and AGILE satellites, suggest that the acceleration of non-thermal particles to the highest energies occurs in magnetic reconnection events - a major change of paradigm in high-energy astrophysics. Most importantly, observations demand that particle acceleration should proceed extremely fast (with accelerating electric field of the order of the magnetic field) and on macroscopic scales (much larger, e.g., than the microscopic plasma skin depth). We are conducting studies of the microphysics of magnetically-dominated plasmas focussing in particular on the highly dynamic regime of explosive reconnection and associated particle acceleration in relativistic plasmas. We are studying the stability and explosive plasma dynamics, particle acceleration and radiation production in a number of idealized plasma configurations that approximate relevant astrophysical sources (like the magnetic ABC structures and interacting flux tubes, as well as generalizations of analytical models of X-point collapse to relativistic plasmas). The well-studied case of the Crab Nebula is taken as a prototypical example for the application of the model. We are combining analytical studies of explosive magnetic dynamics and dissipation in relativistic plasmas with particle-in-cell (PIC) simulations and fluid simulations. The theoretical model, fluid and particle-in-cell simulations are cross-checked for agreement and convergence.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Yield and PDV Measurements of the Godiva-IV Critical Assembly

A high dynamic range, scinillator based detector, the MHD-240, was used to measure the gamma and neutron flux of several prompt critical bursts of the Godiva-IV assembly. The measurements provided the alpha and FWHM for several different burst temperatures. Calibrations of the MHD240 gamma and neutron sensitivity along with MCNP based simulation of the Godiva-IV assembly allowed us to also determine the total fission yield of the burst integrated over approximately 5 ms. In addition a Photo Doppler Velocimetry measurement was conducted to determine the surface motion vibrational frequency of Godiva-IV assembly during the bursts. The combined data were collected to be used as input to multi-physics simulation of the Godiva-IV assembly. This is a preliminary report, there is an ongoing effort to update the MCNP simulations used in the analysis and develop a correction for the room return component of the measured signal.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2021

Yield and PDV Measurements of the Godiva-IV Critical Assembly (Preliminary Report)

A high dynamic range, scinillator based detector, the MHD-240, was used to measure the gamma and neutron flux of several prompt critical bursts of the Godiva-IV assembly. The measurements provided the alpha and FWHM for several different burst temperatures. Calibrations of the MHD240 gamma and neutron sensitivity along with MCNP based simulation of the Godiva-IV assembly will allow us to also determine the total fission yield of the burst integrated over approximately 5 ms. Work is ongoing to check the calibrations of the MHD-240, and improve the MCNP simulations. This is a preliminary report, and the fission yields reported here are not final and are likely inaccurate. The measured alpha and FWHM are not impacted by the calibration issues and are considered final.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2018

NRC HEAF Tests: Imaging & Measurement Methodology Report

The 2018 NRC HEAF tests were conducted in Chalfont Pennsylvania at KEMA High Power Laboratory during the week of September 10th. These scoping tests were executed to determine the most effective measurement methodologies for future tests. The goal of Sandia’s Photometrics group was to provide high-speed quantitative and qualitative imaging of the arcing fault tests for the Nuclear Regulatory Commission. The measurement methods included visible high-speed imaging, high-speed high-dynamic range visible imaging, thermal imaging, and quantitative flow imaging. In addition, data fusion products were generated to visualize instrumentation data and imaging measurements. All imaging has been time synchronized to the start of the arcing event.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Plasma Mirrors For High Power Lasers: A new approach for high repetition rates combined with realistic PIC simulations

We describe a research program to develop high quality plasma mirrors for use with high repetition rate, high power laser facilities to greatly facilitate experiments in high energy density physics, particularly when using solid density targets. A system delivering ultrathin, free standing liquid crystal films that could handle PW class laser pulses was developed that preserved the laser beam image quality and improved pulse contrast by over two orders of magnitude. The pulse contrast improvement was measured using a high dynamic range cross-correlation. The system operated at a repetition rate of several PMs formed in situ per minute. Extension to 1 Hz repetition rates should be possible. As a practical application, a PM system was used to separate laser accelerated electrons from the ultrashort pulse drive laser so that the electron beam emittance could be directly measured. The 20 nm thick PMs did not contribute significantly to emittance degradation. It was also demonstrated that the films could operate in the difficult plasma and laser environment present for GeV laser based electron acceleration. PM operation is still not well understood and much work with PMs is done empirically. Accordingly, we also demonstrated a particle-in-cell based simulation technique that would model PM operation, tracking the PM operation from cold, neutral atoms to a hot dense plasma by accounting for multiphoton ionization, plasma collisionality, and the dynamically changing index of refraction. Simulations in 3D were compared to a 2D based approach that was comparable. Finally, we developed a simpler model that can predict the intensity at which a plasma mirror will have its peak reflectivity.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Briefing Book: Office of Experimental Sciences

Key to OES science is the advancement of experimental capabilities and vibrant partnerships with other elements of NNSA’s Defense Programs. OES fosters an experimental portfolio that spans the space from small scale studies utilizing tabletop instruments through complex and dynamic high energy density; hydrodynamic; and subcritical experiments on flagship national facilities like Los Alamos Neutron Science Center (LANSCE), National Ignition Facility (NIF), Z machine at Sandia National Laboratories, Dual Axis Radiographic Hydrodynamic Test (DARHT), and the U1a Complex in Nevada. Essential to meeting the deterrence challenges that drive OES is a functional strategy for integration of OES with Defense Programs pursuits in modeling and simulation, engineering and technology maturation, and stockpile and production modernization.

42 ENGINEERING↗
DOE OSTI2022

Triton Field Trials - Changes in Habitats, a Literature Review of Monitoring Technologies

Marine energy devices are installed in highly dynamic environments and have the potential to affect benthic and pelagic habitats around them. Regulatory bodies often require baseline characterization and/or post-installation monitoring to determine whether changes in these habitats are being observed. However, a great diversity of technologies is available for surveying and sampling marine habitats. Selecting the most suitable instrument to identify and measure changes in habitats at marine energy sites can become a daunting task. We conducted a thorough review of journal articles, survey reports, and grey literature to extract information about the technologies used, the data collection and processing methods, and the performance and effectiveness of these instruments. We examined documents related to marine energy development, offshore wind farms, oil and gas offshore sites, and other marine industries around the world over the last 20 years, as well as national and international guidelines for surveying habitats around offshore activities. A total of 120 different technologies were identified across six main habitat categories: seafloor, sediment, infauna, epifauna, pelagic, and biofouling. The technologies were organized into 12 broad technology classes: acoustic, corer, dredge, grab, hook and line, net and trawl, plate, remote sensing, scrape samples, trap, visual, and others. Visual was the most common and the most diverse technology class, with applications across all six habitat categories. Sampling designs varied considerably among the reviewed studies but transect was the predominant design for surveying seafloor, epifauna, and pelagic habitats. The most common data analyses were univariate and multivariate statistical analyses aimed at calculating and comparing biodiversity indices, characterizing faunal assemblages or sediment classes, or modeling the distribution of animals related to abiotic parameters. Technologies and sampling methods adaptable and designed to work efficiently in energetic environments have greater success at marine energy sites. In addition, sampling designs and statistical analyses should be carefully thought through to identify differences in faunal assemblages and spatiotemporal changes in habitats.

16 TIDAL AND WAVE POWER↗
DOE OSTI2024

A general mechanistic framework for cross-scale understanding of hot spots and hot moments in carbon and water fluxes

Semi-arid ecosystems, like those in the American Southwest, exert a massive impact on the interannual variability of carbon and water cycling. Unfortunately, these carbon and water fluxes are notoriously difficult to predict due to their high spatial and temporal variability, which is poorly captured by the current generation of vegetation models. Indeed, this region is exemplified by the ‘hot spots and hot moments’ concept, which states that small areas in space (‘hot spots’) and transient moments in time (‘hot moments’) exert an outsized influence on biogeochemical cycling. However, the factors that regulate these pulses in biogeochemical activity are unknown, as is their variability across space and time. These uncertainties severely limit efforts to better represent hot spots and hot moments in models. Here, we seek to develop a generalized method for detecting and quantifying the importance of hot spots and hot moments from individual plant to regional scales. Underpinning this method is our recently developed statistical approach for identifying hot spots and hot moments. By applying this method to semi-continuous measurements of plant water status, a depth profile of soil water potential, and ecosystem fluxes via eddy covariance, we will track the fate of water through the soil-plant-atmosphere continuum and identify the mechanistic drivers of these transient pulses in biogeochemical activity. Then, we will expand this approach across a broad network of Ameriflux towers, and apply a machine learning approach that will allow us to upscale measurements of hot spots and hot moments across the American Southwest and quantify their impact on carbon and water cycles. These products will allow us to identify hot spots and hot moments across spatio-temporal scales and will serve as crucial data sources for validating a new generation of models that can better capture highly dynamic carbon and water fluxes. The proposed method will be easily transferable across biomes and will serve as a framework for future research on hot spots and hot moments across the plant ecophysiology, biometeorology, and vegetation modeling communities.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Through the Windshield Driver Recognition

Biometric recognition of vehicle occupants in unconstrained environments is rife with a host of challenges. In particular, the complications arising from imaging through vehicle windshields provide a significant hurdle. Distance to target, glare, poor lighting, head pose of occupants, and speed of vehicle are some of the challenges. We explore the construction of a multi-unit computational camera system to mitigate these challenges in order to obtain accurate and consistent face recognition results. This paper documents the hardware components and software design of the computational imaging system. Also, we document the use of RCNN for face detection and GAN for machine learning-inspired High Dynamic Range Imaging, artifact removal, and image fusion.

Cornett, David↗
DOE OSTI2023

The Impact of Operated Window Shading on Visual Comfort, Non-Visual Health, and Energy Demand from Electric Lighting

This paper introduces a simulation-based workflow to assess annual circadian lighting performance, glare risk and energy demand for an array of seated view positions under operated shading and electric lighting conditions. This workflow uses a combination of 9-band and 81-band simulations to represent daylight and electric lighting respectively. Annual daylight-driven calculations rely on a python-based code provided in the LARK simulation engine which was used to run 180-degree high dynamic range (HDR) renderings with 9-bands of spectral resolution. The results reveal the impact of shading systems on equivalent melanopic lux (EML) and daylight glare probability (DGP) over time and the energy demand (kWh) from electric lighting systems to supplement eye-level recommendations from the WELL v2 Building Standard.

Rockcastle, Siobhan↗
DOE OSTI2021

Transcutaneous and End-Tidal CO 2 Measurements in Hypoxia and Hyperoxia

BACKGROUND: Transcutaneous measurement of carbon dioxide (CO 2 ) has been proposed for physiological monitoring of tactical jet aircrew because in some clinical settings it mirrors arterial CO 2 partial pressure (P a co 2 ). End-tidal monitoring in laboratory settings is known to give high-fidelity estimates of P a co 2 . METHODS: The correspondence between end-tidal (P ET co 2 ) and transcutaneous Pco 2 (tcPco 2 ) was examined in healthy volunteers under laboratory conditions of hyperoxia and hypoxia. Rest and exercise, skin heating and cooling, hyperventilation, and induced CO 2 retention were employed. RESULTS: Neither measure followed all known changes in P a co 2 and tcPco 2 changed when the skin temperature near the probe changed. Bland-Altman analysis showed significant nonzero slopes under most conditions. Regression analysis indicated that oxygen partial pressure (Po 2 ) in tissue measured as transcutaneous Po 2 (tcPo 2 ) is an important explanatory variable for tcPco 2 in addition to P ET co 2 , and that local skin temperature also has an effect. Additionally, absorption atelectasis from breathing 100% O 2 may cause P ET co 2 to deviate from P a co 2 . DISCUSSION: Even as a trend indicator for P a co 2 , tcPco 2 is not useful under conditions that resemble those in the highly dynamic tactical jet aircraft environment. P ET co 2 is also not a good indicator of CO 2 status in pilots who breathe nearly 100% O 2 . Shykoff BE, Lee LR, Gallo M, Griswold CA. Transcutaneous and end-tidal CO 2 measurements in hypoxia and hyperoxia . Aerosp Med Hum Perform. 2021; 92(11):864–872 .

Biophysics↗
DOE OSTI2022

Characterizing Natural Organic Matter Transformations by Microbial Communities in Terrestrial Subsurface Ecosystems: A Critical Review of Analytical Techniques and Challenges

Determining the mechanisms, traits, and pathways that regulate microbial transformation of natural organic matter (NOM) is critical to informing our understanding of the microbial impacts on the global carbon cycle. The capillary fringe of subsurface soils is a highly dynamic environment that remains poorly understood. Characterization of organo-mineral chemistry combined with a nuanced understanding of microbial community composition and function is necessary to understand microbial impacts on NOM speciation in the capillary fringe. We present a critical review of the popular analytical and omics techniques used for characterizing complex carbon transformation by microbial communities and focus on how complementary information obtained from the different techniques enable us to connect chemical signatures with microbial genes and pathways. This holistic approach offers a way forward for the comprehensive characterization of the formation, transformation, and mineralization of terrestrial NOM as influenced by microbial communities.

59 BASIC BIOLOGICAL SCIENCES↗