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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Paintable Heat-Reflective Coatings for Low-Cost Energy Efficient Windows

The major objective of this effort is to manufacture a paintable coating to inexpensively retrofit energy-inefficient windows with a heat-reflective, visibly transparent film. This coating will drastically reduce cooling costs for millions of homes and buildings and lower the Nation’s greenhouse gas emissions. Widespread implementation could reduce the national consumption of electricity for cooling by billions of kWh, saving billions of dollars per year. This improved energy efficiency would decrease CO2 emissions by billions kg per year, the equivalent to removing millions of cars from the road. Although near-IR reflective adhesive films are commercially available products and have demonstrated significant energy efficiency enhancement, high upfront costs largely deter potential consumers across all sectors. The technology developed under this award was proposed to disrupt the building envelope market, by providing an inexpensive coating that can be directly applied by consumers to improve the energy efficiency of virtually all window types. The proof of concept for a paintable, DIY applicable, visibly transparent, and infrared reflective coating was achieved, laying the foundation for future technology development in this area.

14 SOLAR ENERGY↗
DOE OSTI2024

Modeling Partial Reflection Paths for Infrasound Analysis

Numerical methods enabling simulation of scattered and partially reflected infrasonic propagation paths produced by interaction with fine-scale structure in the middle atmosphere have been implemented in the infraGA ray tracing software. This capability enables simulation of ensonification in the classical stratospheric “shadow zone” that has been observed during the Humming Roadrunner and LSECE surface explosion campaigns as well as in other data sets. In the case of LSECE, a pair of stations roughly 140 kilometers east of the source location observed arrivals with celerities (horizontal group velocities) slightly slower than observed stratospheric paths at similar azimuths. The arrivals exhibited increasing trace velocity later in the wavetrain indicating a steepening of the arrival path for longer or slower propagation paths. Simulation of partially reflected paths using the updated infraGA software methods finds good agreement between observed and predicted infrasonic ensonification at these locations within the stratospheric shadow zone. Further development of the partial reflection physics and comparison with other data sets is needed to more robustly understand how such anomalous infrasonic signals can be predicted; however, the demonstration of this capability is a promising first step in such analyses.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Identification of Metal Stresses in Arabidopsis thaliana Using Hyperspectral Reflectance Imaging

Industrial accidents, such as the Fukushima and Chernobyl disasters, release harmful chemicals into the environment, covering large geographical areas. Natural flora may serve as biological sensors for detecting metal contamination, such as cesium. Spectral detection of plant stresses typically employs a few select wavelengths and often cannot distinguish between different stress phenotypes. In this study, we apply hyperspectral reflectance imaging in the visible and near-infrared along with multivariate curve resolution (MCR) analysis to identify unique spectral signatures of three stresses in Arabidopsis thaliana : salt, copper, and cesium. While all stress conditions result in common stress physiology, hyperspectral reflectance imaging and MCR analysis produced unique spectral signatures that enabled classification of each stress. As the level of potassium was previously shown to affect cesium stress in plants, the response of A. thaliana to cesium stress under variable levels of potassium was also investigated. Increased levels of potassium reduced the spectral response of A. thaliana to cesium and prevented changes to chloroplast cellular organization. While metal stress mechanisms may vary under different environmental conditions, this study demonstrates that hyperspectral reflectance imaging with MCR analysis can distinguish metal stress phenotypes, providing the potential to detect metal contamination across large geographical areas.

multivariate curve resolution↗
DOE OSTI2016

REFLECTED CHARGED PARTICLE POPULATIONS AROUND DIPOLAR LUNAR MAGNETIC ANOMALIES

In this work we analyze and compare the reflected particle populations for both a horizontal and a vertical dipole model embedded in the lunar surface, representing the solar wind interaction with two different lunar magnetic anomaly (LMA) structures. Using the 3D full-kinetic electromagnetic code iPic3D, in combination with a test-particle approach to generate particle trajectories, we focus on the ion and electron dynamics. Whereas the vertical model electrostatically reflects ions upward under both near-parallel and near-perpendicular angles with respect to the lunar surface, the horizontal model only has a significant shallow component. Characterizing the electron dynamics, we find that the interplay of the mini-magnetosphere electric and magnetic fields is capable of temporarily trapping low-energy electrons and possibly ejecting them upstream. Our results are in agreement with recent high-resolution observations. Low- to medium-altitude ion and electron observations might be excellent indicators to complement orbital magnetic field measurements and better uncover the underlying magnetic field structure. The latter is of particular importance in defining the correlation between LMAs and lunar swirls, and further testing the solar wind shielding hypothesis for albedo markings due to space weathering. Observing more reflected ions does not necessarily point to the existence of a mini-magnetosphere.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

The Absolute Reflectance and New Calibration Site of the Moon

How bright the Moon is forms a simple but fundamental and important question. Although numerous efforts have been made to answer this question such as use of sophisticated electro-optical measurements and suggestions for calibration sites, the answer is still debated. An in situ measurement with a calibration panel on the surface of the Moon is crucial for obtaining the accurate absolute reflectance and resolving the debate. China’s Chang’E-3 (CE-3) “Yutu” rover accomplished this type of measurement using the Visible-Near Infrared Spectrometer (VNIS). The measurements of the VNIS, which were at large emission and phase angles, complement existing measurements for the range of photometric geometry. The in situ reflectance shows that the CE-3 landing site is very dark with an average reflectance of 3.86% in the visible bands. The results are compared with recent mission instruments: the Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC), the Spectral Profiler (SP) on board the SELENE, the Moon Mineralogy Mapper (M{sup 3}) on board the Chandrayaan-1, and the Chang’E-1 Interference Imaging Spectrometer (IIM). The differences in the measurements of these instruments are very large and indicate inherent differences in their absolute calibration. The M{sup 3} and IIM measurements are smaller than LROC WAC and SP, and the VNIS measurement falls between these two pairs. When using the Moon as a radiance source for the on-orbit calibration of spacecraft instruments, one should be cautious about the data. We propose that the CE-3 landing site, a young and homogeneous surface, should serve as the new calibration site.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Theoretical Reflectance Spectra of Earth-like Planets through Their Evolutions: Impact of Clouds on the Detectability of Oxygen, Water, and Methane with Future Direct Imaging Missions

In the near-future, atmospheric characterization of Earth-like planets in the habitable zone will become possible via reflectance spectroscopy with future telescopes such as the proposed LUVOIR and HabEx missions. While previous studies have considered the effect of clouds on the reflectance spectra of Earth-like planets, the molecular detectability considering a wide range of cloud properties has not been previously explored in detail. In this study, we explore the effect of cloud altitude and coverage on the reflectance spectra of Earth-like planets at different geological epochs and examine the detectability of O{sub 2},H{sub 2}O, and CH{sub 4} with test parameters for the future mission concept, LUVOIR, using a coronagraph noise simulator previously designed for WFIRST-AFTA. Considering an Earth-like planet located at 5 pc away, we have found that for the proposed LUVOIR telescope, the detection of the O{sub 2} A-band feature (0.76 μm) will take approximately 100, 30, and 10 hr for the majority of the cloud parameter space modeled for the atmospheres with 10%, 50%, and 100% of modern Earth O{sub 2} abundances, respectively. In particular, for the case of ≳50% of modern Earth O{sub 2} abundance, the feature will be detectable with an integration time ≲10 hr as long as there are lower-altitude (≲8 km) clouds with a global coverage of ≳20%. For the 1% of the modern Earth O{sub 2} abundance case, however, it will take more than 100 hr for all the cloud parameters we modeled.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Experimental Study of Alfvén Wave Reflection from an Alfvén-speed Gradient Relevant to the Solar Coronal Holes

Abstract We report the first experimental detection of a reflected Alfvén wave from an Alfvén-speed gradient under conditions similar to those in coronal holes. The experiments were conducted in the Large Plasma Device at the University of California, Los Angeles. We present the experimentally measured dependence of the coefficient of reflection versus the wave inhomogeneity parameter, i.e., the ratio of the wavelength of the incident wave to the length scale of the gradient. Two-fluid simulations using the Gkeyll code qualitatively agree with and support the experimental findings. Our experimental results support models of wave heating that rely on wave reflection at low heights from a smooth Alfvén-speed gradient to drive turbulence.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

Pan-spectral observing system simulation experiments of shortwave reflectance and long-wave radiance for climate model evaluation

Abstract. Top-of-atmosphere (TOA) spectrally resolved shortwave reflectances and long-wave radiances describe the response of the Earth's surface and atmosphere to feedback processes and human-induced forcings. In order to evaluate proposed long-duration spectral measurements, we have projected 21st Century changes from the Community Climate System Model (CCSM3.0) conducted for the Intergovernmental Panel on Climate Change (IPCC) A2 Emissions Scenario onto shortwave reflectance spectra from 300 to 2500 nm and long-wave radiance spectra from 2000 to 200 cm –1 at 8 nm and 1 cm –1 resolution, respectively. The radiative transfer calculations have been rigorously validated against published standards and produce complementary signals describing the climate system forcings and feedbacks. Additional demonstration experiments were performed with the Model for Interdisciplinary Research on Climate (MIROC5) and Hadley Centre Global Environment Model version 2 Earth System (HadGEM2-ES) models for the Representative Concentration Pathway 8.5 (RCP8.5) scenario. The calculations contain readily distinguishable signatures of low clouds, snow/ice, aerosols, temperature gradients, and water vapour distributions. The goal of this effort is to understand both how climate change alters reflected solar and emitted infrared spectra of the Earth and determine whether spectral measurements enhance our detection and attribution of climate change. This effort also presents a path forward to understand the characteristics of hyperspectral observational records needed to confront models and inline instrument simulation. Such simulation will enable a diverse set of comparisons between model results from coupled model intercomparisons and existing and proposed satellite instrument measurement systems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Reflection and transmission of electromagnetic pulses at a planar dielectric interface -- theory and quantum lattice simulations

There is considerable interest in the application of quantum information science to advance computations in plasma physics. A particular point of curiosity is whether it is possible to take advantage of quantum computers to speed up numerical simulations relative to conventional computers. Many of the topics in fusion plasma physics are classical in nature. In order to implement them on quantum computers it will require couching a classical problem in the language of quantum mechanics. Electromagnetic waves are routinely used in fusion experiments to heat a plasma or to generate currents in the plasma. The propagation of electromagnetic waves is described by Maxwell equations with an appropriate description of the plasma as a dielectric medium. Before advancing to the tensor dielectric of a magnetized plasma, this paper considers electromagnetic wave propagation in a one-dimensional inhomogeneous scalar dielectric. The classic theory of scattering of plane electromagnetic waves at a planar interface, separating two different dielectric media, leads to Fresnel equations for reflection and transmission coefficients. In contrast to plane waves, this paper is on the reflection and transmission of a spatially confined electromagnetic pulse. Following an analytical formulation for the scattering of a Gaussian pulse, it is deduced that the maximum transmission coefficient for a pulse is $\sqrt{n_2/n_1}$ times that for a plane wave; the incident and transmitted pulses propagating in dielectric media with refractive indices $n_1$ and $n_2$, respectively. The analytical theory is complemented by numerical simulations using a quantum lattice algorithm for Maxwell equations. The algorithm, based on the Riemann-Silberstein-Weber representation of the electromagnetic fields and expressed in term of qubits, is an interleaved sequence of entangling operators at each lattice site and unitary streaming operators which transmit information from one site to an adjacent lattice site. Besides substantiating results from the theory for Gaussian pulses, numerical simulations show their validity for non-Gaussian pulses. Apart from their time-asymptotic forms, the simulations display an interplay between the incident, reflected, and transmitted pulses in the vicinity of the transition region between two dielectric media.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2013

Validation of FSP Reactor Design with Sensitivity Studies of Beryllium-Reflected Critical Assemblies

The baseline design for space nuclear power is a fission surface power (FSP) system: sodium-potassium (NaK) cooled, fast spectrum reactor with highly-enriched-uranium (HEU)-O 2 fuel, stainless steel (SS) cladding, and beryllium reflectors with B4C control drums. Previous studies were performed to evaluate modeling capabilities and quantify uncertainties and biases associated with analysis methods and nuclear data. Comparison of Zero Power Plutonium Reactor (ZPPR)-20 benchmark experiments with the FSP design indicated that further reduction of the total design model uncertainty requires the reduction in uncertainties pertaining to beryllium and uranium cross-section data. Further comparison with three beryllium-reflected HEU-metal benchmark experiments performed at the Oak Ridge Critical Experiments Facility (ORCEF) concluded the requirement that experimental validation data have similar cross section sensitivities to those found in the FSP design. A series of critical experiments was performed at ORCEF in the 1960s to support the Medium Power Reactor Experiment (MPRE) space reactor design. The small, compact critical assembly (SCCA) experiments were graphite- or beryllium-reflected assemblies of SS-clad, HEU-O 2 fuel on a vertical lift machine. All five configurations were evaluated as benchmarks. Two of the five configurations were beryllium reflected, and further evaluated using the sensitivity and uncertainty analysis capabilities of SCALE 6.1. Validation of the example FSP design model was successful in reducing the primary uncertainty constituent, the Be(n,n) reaction, from 0.28 %$\delta$k/k to 0.0004 %$\delta$k/k. Further assessment of additional reactor physics measurements performed on the SCCA experiments may serve to further validate FSP design and operation.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Corrosion-resistant multilayer structures with improved reflectivity

In one general embodiment, a thin film structure includes a substrate; a first corrosion barrier layer above the substrate; a reflective layer above the first corrosion barrier layer, wherein the reflective layer comprises at least one repeating set of sub-layers, wherein one of the sub-layers of each set of sub-layers being of a corrodible material; and a second corrosion barrier layer above the reflective layer. In another general embodiment, a system includes an optical element having a thin film structure as recited above; and an image capture or spectrometer device. In a further general embodiment, a laser according to one embodiment includes a light source and the thin film structure as recited above.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Fault Imaging with High-Resolution Seismic Reflection for Earthquake Hazard and Geothermal Resource Assessment in Reno, Nevada

The Truckee Meadows basin is situated adjacent to the Sierra Nevada microplate, on the western boundary of the Walker Lane. Being in the transition zone between a range-front normal fault on the west and northwest-striking right-lateral strike slip faults to the east, there is no absence of faulting in this basin. The Reno- Sparks metropolitan area is located in this basin, and with a signi cant population living here, it is important to know where these faults are. High-resolution seismic reflection surveys are used for the imaging of these faults along the Truckee River, across which only one fault was previously mapped, and in southern Reno near and along Manzanita Lane, where a swarm of short faults has been mapped. The reflection profiles constrain the geometries of these faults, and suggest additional faults not seen before. Used in conjunction with depth to bedrock calculations and gravity measurements, the seismic reflection surveys provide de nitive locations of faults, as well as their orientations. O sets on these faults indicate how active they are, and this in turn has implications for seismic hazard in the area. In addition to seismic hazard, the faults imaged here tell us something about the conduits for geothermal fluid resources in Reno.

15 GEOTHERMAL ENERGY↗
DOE OSTI2015

Results of Partially-Reflected Critical Experiments in Square-Pitched Arrays of Water-Moderated 6.9 Percent Enriched Fuel Rods

The Seven Percent Critical Experiment (7uPCX) was designed to provide benchmark criticality and reactor physics data for water-moderated pin-fueled nuclear reactor cores. The enrichment of the fuel was chosen to explore the enrichment range above the current 5% ceiling for US commercial pressurized water reactors. The experiment was part of the US Department of Energy (DOE) Nuclear Energy Research Initiative (NERI) Project 01-124 titled “Reactor Physics and Criticality Benchmark Evaluations for Advanced Nuclear Fuel”. The NERI project was a collaboration between AREVA Federal Services, LLC; the University of Florida; Oak Ridge National Laboratory; and Sandia National Laboratories (SNL). The experiments at Sandia are currently supported by the DOE National Nuclear Security Administration Nuclear Criticality Safety Program. Two sets of benchmark experiments have been completed and documented as LEU-COMP-THERM-080 and LEU-COMP-THERM-078. Those experiments were done with the number of fuel rods in the fully-reflected array as the approach parameter. The experiments reported here are similar to those in LEU-COMP-THERM-080 except that the arrays are partially-reflected – the arrays were larger than would be possible with full reflection and the approach-to-critical experiments were done with the depth of the water in the critical assembly as the approach parameter. These experiments are reported as LEU-COMP-THERM-096.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Analysis-Software for Hyperspectral Algal Reflectance Probes v. 1.0

This software provides onsite analysis of the hyperspectral reflectance data acquired on an outdoor algal pond by a multichannel, fiber-coupled spectroradiometer. The analysis algorithm is based on numerical inversion of a reflectance model, in which the above-water reflectance is expressed as a function of the single backscattering albedo, which is dependent on the backscatter and absorption coefficients of the algal culture, which are in turn related to the algal biomass and pigment optical activity, respectively. Prior to the development of this software, while raw multichannel data were displayed in real time, analysis required a post-processing procedure to extract the relevant parameters. This software provides the capability to track the temporal variation of such culture parameters in real time, as raw data are being acquired, or can be run in a post processing mode. The software allows the user to select between different algal species, incorporate the appropriate calibration data, and observe the quality of the resulting model inversions.

Timlin, Jerilyn A.↗
DOE OSTI2017

Gradient SiNO anti-reflective layers in solar selective coatings

A solar selective coating includes a substrate, a cermet layer having nanoparticles therein deposited on the substrate, and an anti-reflection layer deposited on the cermet layer. The cermet layer and the anti-reflection layer may each be formed of intermediate layers. A method for constructing a solar-selective coating is disclosed and includes preparing a substrate, depositing a cermet layer on the substrate, and depositing an anti-reflection layer on the cermet layer.

Ren, Zhifeng↗
DOE OSTI2017

Reflective article having a sacrificial cathodic layer

The present invention relates to reflective articles, such as solar mirrors, that include a sacrificial cathodic layer. The reflective article, more particularly includes a substrate, such as glass, having a multi-layered coating thereon that includes a lead-free sacrificial cathodic layer. The sacrificial cathodic layer includes at least one transition metal, such as a particulate transition metal, which can be in the form of flakes (e.g., zinc flakes). The sacrificial cathodic layer can include an inorganic matrix formed from one or more organo-titanates. Alternatively, the sacrificial cathodic layer can include an organic polymer matrix (e.g., a crosslinked organic polymer matrix formed from an organic polymer and an aminoplast crosslinking agent). The reflective article also includes an outer organic polymer coating, that can be electrodeposited over the sacrificial cathodic layer.

36 MATERIALS SCIENCE↗
DOE OSTI2017

ATALANTE research facility-implementation of a rule of fractions for the management of reflecting materials in mass-limited units

ATALANTE, a research unit located in Marcoule, is one of the main Nuclear Facilities of the French CEA. As concerns criticality risk prevention, this facility is divided into work units mostly managed through a mass control mode. The authorized limit is 350 g of fissile material with {sup 239}Pu-H{sub 2}O as reference fissile medium. This mass limit was determined considering a reflection by 20 cm of water. Under these conditions, some neutronic reflectors which are more efficient than water can only be authorized in limited quantities. In ATALANTE the reflecting materials identified as requiring a specific form of management are lead, uranium ({sup 235}U/U{sub total} = 1%), graphite, heavy water and beryllium. Initially a maximum permissible mass was determined for each of these materials taken separately. However, this method requires that when different reflectors are present simultaneously, the sum of the masses of all these reflectors must be less than the limit specified for the most penalizing of them. This rule has proved to be too restrictive for the operators. A new rule has therefore been implemented: the rule of fractions. Criticality calculations were performed to demonstrate that this rule is acceptable. The geometric configurations studied involved a sphere of 350 g of {sup 239}Pu moderated by water and reflected by various masses of 2 to 6 reflectors (successions of concentric shells), followed by 20 cm of water. It was concluded that compliance with the new rule makes it possible to ensure criticality safety in the simultaneous presence of different reflectors. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Demonstration and Automation of Reflected Target Optical Measurement for Heliostats

Accurate optical surfaces are a primary driver of concentrated solar power plant performance. Errors in pointing and tracking mirrors, the canting of individual mirror facets, and the surface slope of the mirror itself can be caused by errors during assembly, transportation, wind loading, gravity, and many other sources. The tools that exist to measure these error sources today largely rely on fringe deflectometry (SOFAST, QDec, others), or photogrammetry with targets attached to the mirror surface. Since 2022, NREL has been developing a measurement method called the Reflected Target Non-intrusive Assessment (ReTNA) system. This system differs from most established methods in that we perform deflectometry with a pattern of coded targets, identified in space with photogrammetry. Reflected target systems have several advantages over traditional fringe deflectometry systems. Firstly, they can be operated in bright or ambient lighting, a challenge for fringe systems that use a projector and screen. Reflected target systems also can use a much lighter and less expensive target than projector-based systems. Lastly, 2D slope measurement can be solved from a single image, which leads to several advantages for accommodating faster measurements and smaller sized targets. These advantages make ReTNA particularly well-suited for applications where there are space or lighting constraints, like performing heliostat quality assurance on an assembly line. It's also useful when a lightweight, flexible system is needed, like for heliostat developers to quickly measure a new heliostat design at different orientations, to observe gravitational effects on the mirror surface shape. In the last year, significant improvements were made to this tool to make it more useful for these applications. These improvements were focused around validation of the ReTNA measurement system, and automation of the setup and measurement process. First, we present an improved ReTNA layout, for use on the heliostat assembly line. Next, we detail the various changes to the ReTNA software and computer vision methods to automate data collection in this new setup, and lessons learned from this process. The goal with this new setup is to perform a full heliostat surface characterization without removing the mirror from the assembly line. Lastly, we share results from several ReTNA validation studies undertaken over the last year. These include repeated ReTNA measurement on demonstration mirror facets, comparisons with other optical measurement tools, and some studies aimed at quantifying the uncertainty of ReTNA measurement under various constraints (mirror-target spacing, camera resolution, etc.). These results are compared with 2024 HelioCon performance targets, and our planned next steps for the ReTNA measurement system are presented.

CSP↗