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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Implementation of an Unsteady PSP System in the NASA TDT

An unsteady pressure-sensitive paint (uPSP) system has been developed to provide time-resolved pressure measurements in the NASA Langley Transonic Dynamics Tunnel (TDT). Obtaining these measurements necessitated the development of environmental enclosures to protect the high-speed camera and ultraviolet lights required for uPSP from the harsh environment present during tunnel operation. Since the facility main drive was non-functioning during the testing window, performance of the uPSP system was demonstrated using an impinging jet with a passive oscillator attachment to provide unsteady flow with a known frequency independent of amplitude. Measurements were obtained for tunnel pressures ranging from 565 to 2116 psf, and model angles of attack between -4 degrees and 4 degrees. Results indicate that the system is capable of measuring surface pressure differentials on the order of 0.01 psi at full scale with a camera frame rate of at least 10 kHz. Spectral analysis shows that the fundamental frequency of the oscillating jet is captured by the uPSP system, as are the second and third harmonics. Dynamic mode decomposition highlights the dominant coherent spatial structures of the surface pressure, along with the associated frequency and growth rate of each mode, allowing for a de-noised reconstruction of the uPSP measurements. The experimental campaign outlined within this report also confirmed compatibility of the uPSP system with the TDT facility data acquisition system, and verified the successful integration with existing processing capabilities within the NASA advanced supercomputing environment. Note: this presentation is an MP4 video with sound, color with a run time of 10 minutes 37 seconds.

unsteady pressure-sensitive paint↗
NASA NTRSDate not supplied

Validating uPSP with Transducers

Unsteady Pressure-Sensitive Paint (uPSP) technology provides simultaneously high-frequency and high-spatial resolution surface pressure fluctuation measurements. It has demonstrated value in wind tunnel test facilities to evaluate aerospace vehicle unsteady aerodynamics. The calibration of measurements from digital pixel counts into corresponding physical units relies on both lab-based and in-situ calibration steps, and its validation is both challenging and critical to adoption of the technology. We present a rigorous methodology for direct comparison of uPSP-derived surface pressure measurements to reference pressure transducer data based on a model of the camera-based measurement error, a model of the flow field pressure signal, and their propagation through the uPSP data reduction algorithm. The methodology is demonstrated on data collected in a small-scale, subsonic wind tunnel test as well as data collected from a Space Launch System unsteady aerodynamics characterization test at the NASA Ames Research Center Unitary Plan Wind Tunnel Complex.

Pressure-Sensitive Paint↗
NASA NTRSDate not supplied

Steady Surface Pressure Measurement via the Lifetime Method With High-Speed Cameras in NASA's Unitary Plan Wind Tunnel

High spatial resolution measurement of steady surface pressure via pressure-sensitive paint at NASA Ames has traditionally relied on specialized cameras equipped to accumulate charge over multiple exposures, whereas measurement of the fluctuating component of pressure uses an altogether separate set of high-speed cameras. To reduce complexity of installation, data acquisition, and processing, we have implemented methods to use a single set of commercial off-the-shelf cameras to produce both steady and unsteady pressure measurements. Both imaging systems were installed in the 11-by 11-foot NASA Ames Unitary Plan Wind Tunnel and acquired images of a scaled model of the Space Launch System Block 1B Crew and Cargo configurations over a variety of flow conditions. This work focuses on methods for data acquisition, processing, and calibration to produce steady-state pressure estimates on the surface of the wind tunnel model based on the lifetime method. It will then compare the steady solutions produced by the legacy and high-speed imaging systems.

Pressure Sensitive Paint↗
DOE OSTI2017

Performance Evaluation of a Thermal Load Reduction System in a Hyundai Sonata PHEV

Increased adoption of electric-drive vehicles (EDVs) requires overcoming hurdles including limited vehicle range. Vehicle cabin heating and cooling demand for occupant climate control requires energy from the main battery and has been shown to significantly degrade vehicle range. During peak cooling and heating conditions, climate control can require as much or more energy as propulsion. As part of an ongoing project, NREL and project partners Hyundai America Technical Center, Inc. (HATCI), Gentherm , Pittsburgh Glass Works (PGW), PPG Industries, Sekisui, 3M, and Hanon Systems developed a thermal load reduction system in order to reduce the range penalty associated with electric vehicle climate control. Solar reflective paint, solar control glass, heated and cooled/ventilated seats, heated surfaces, and heated windshield with door demisters were integrated into a Hyundai Sonata plug-in hybrid electric vehicle (PHEV). Cold weather field-testing was conducted in Fairbanks, Alaska while warm weather testing was conducted in Death Valley, California to assess the system performance in comparison to the baseline production vehicle. In addition, environmental chamber testing at peak heating and cooling conditions was performed to assess the performance of the system in standardized conditions compared to the baseline. Experimental results are presented in this paper providing quantitative data to automobile manufacturers on the impact of climate control thermal load reduction technologies to increase the advanced thermal technology adoption and market penetration of electric drive vehicles.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2015

Conceptual Model and Risk Assessment of Waste Package Evolution - 15643

A generic disposal facility model was created to mirror disposal of low-level radioactive waste in a humid environment. The standard waste package used is a painted and primed carbon steel box stacked four high and placed next to one another within the disposal facility, preventing outward deformations of individual boxes. Waste is placed in the facility in sections, and as each section is filled it is covered with a layer of natural soil. It was assumed that boxes are exposed to natural precipitation rates for approximately 12 months, reduced to natural background infiltration to simulate the soil cover, and dropping to 1% of background infiltration when the facility is filled and a water-shedding interim cover is installed. It was also assumed that each box retains its structural integrity at the time of disposal, with the exception of the top box, which has its lid collapse inward from the overlying soil cover. Waste packages experience different rates of corrosion, differential amounts of infiltration, and fill with liquid at different rates based on when and where they are placed in the facility. Using historical literature and DOE site reports, calculations were made to estimate a range of waste package failure outcomes. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Multicolor Photonic Pigments for Rotation-Asymmetric Mechanochromic Devices

Photonic crystals are extensively explored to replace inorganic pigments and organic dyes as coloring elements in printing, painting, sensing, and anti-counterfeiting due to their brilliant structural colors, chemical stability, and environmental friendliness. However, most existing photonic-crystal-based pigments can only display monochromatic colors once made, and generating multicolors has to start with designing different building blocks. In this work, a novel photonic pigment featuring highly tunable structural colors in the entire visible spectrum, made by the magnetic assembly of monodisperse nanorods into body-centered-tetragonal photonic crystals, is reported. Their prominent magnetic and crystal anisotropy makes it efficient to generate multicolors using one photonic pigment by magnetically controlling the crystal orientation. Further, the combination of angle-dependent diffraction and magnetic orientation control enables the design of rotation-asymmetric photonic films that display distinct patterns and encrypted information in response to rotation. The efficient multicolor generation through precise orientational control makes this novel photonic pigment promising in developing high-performance structural-colored materials and optical devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Direct Writing of Additive-Free MXene-in-Water Ink for Electronics and Energy Storage

Additive-free, single step formulations of MXene-in-water inks are developed from clay-like titanium carbide (Ti 3 C 2 ) sediments. Solution-processable Ti 3 C 2 inks are compatible with stamping, printing, painting, and writing on a variety of substrates. Specifically, MXene-in-water inks at higher concentrations of 30 mg mL -1 are employed in commercially available pens for dispensing and patterning 2D MXene directly. These MXene pens are employed either manually or automatically using an AxiDraw, enabling direct-writing and complex patterning of functional MXene devices. Versatile MXene pens show compatible writing on a variety of substrates, including paper and polymers, where the deposited ink is used as a passive circuit, similar to silver and copper nanoparticle inks. Written MXene lines without additional post-treatment exhibit length dependent resistance, showing typical resistivity values between carbon based and metal nanoparticle inks. Current collector-free fabrication of MXene micro-supercapacitors is demonstrated on unconventional platforms including paper, textiles, and curved surfaces directly.

catalysis (heterogeneous)↗
DOE OSTI2020

Microstructural and chemical characterization of a purple pigment from a Faiyum mummy portrait

Results are presented from analyses that were conducted to explain the presence of chromium, detected noninvasively using energy dispersive X-ray fluorescence (XRF), in the unusually large (2-3mm diameter) rough gem-like purple pigment particles in the paint used for a Faiyum mummy portrait. An approximately 50 µm diameter particle of the chromium-containing purple pigment was extracted from the Portrait of a Bearded Man, dated to Roman Imperial Egypt in the second century, circa 170-180 CE, accession #32.6 in the Walters Art Museum collection. The particle was characterized using energy dispersive X-ray fluorescence analysis, electron microscopy, diffraction, and atom probe tomography. It is demonstrated that the purple pigment particle is a heterogeneous organic pigment, specifically, a lake pigment likely derived from either plant or insect matter, which contains minor percentages of both transition metals and alkali / alkali earth metals, with nanometer-scale crystallites of lead carbonates and sulfates. The analyses revealed for the first time the nanoscale microstructure and stratigraphy in an ancient lake pigment. Results suggest that similarities with respect to time-period and place of production may be developed among unprovenienced Faiyum mummy portraits to help localize workshops or artists, using analyses focused on lake pigments to characterize specifically metal-based mordants.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Insight into the Structural and Emissive Behavior of a Three‐Dimensional Americium(III) Formate Coordination Polymer

Abstract We report the structural, vibrational, and optical properties of americium formate (Am(CHO 2 ) 3 ) crystals synthesized via the in situ hydrolysis of dimethylformamide (DMF). The coordination polymer features Am 3+ ions linked by formate ligands into a three‐dimensional network that is isomorphous to several lanthanide analogs, (e. g., Eu 3+ , Nd 3+ , Tb 3+ ). Structure determination revealed a nine‐coordinate Am 3+ metal center that features a unique local C 3v symmetry. The metal–ligand bonding interactions were investigated by vibrational spectroscopy, natural localized molecular orbital calculations, and the quantum theory of atoms in molecules. The results paint a predominantly ionic bond picture and suggest the metal‐oxygen bonds increase in strength from Nd−O 5 D 1′ → 7 F 0′ emission band is observed and dominates the emission spectrum. This behavior is unusual and is attributed to the C 3v coordination environment of the metal center.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Winter connectivity and leapfrog migration in a migratory passerine

Abstract Technological advances in migratory tracking tools have revealed a remarkable diversity in migratory patterns. One such pattern is leapfrog migration, where individuals that breed further north migrate to locations further south. Here, we analyzed migration patterns in the Painted Bunting ( Passerina ciris ) using a genetic‐based approach. We started by mapping patterns of genetic variation across geographic space (called a genoscape) using 386 individuals from 25 populations across the breeding range. We then genotyped an additional 230 samples from 31 migration stopover locations and 178 samples from 16 wintering locations to map patterns of migratory connectivity. Our analyses of genetic variation across the breeding range show the existence of four genetically distinct groups within the species: Eastern, Southwestern, Louisiana, and Central groups. Subsequent assignment of migrating and wintering birds to genetic groups illustrated that birds from the Central group migrated during the fall via western Mexico or southern Texas, spent the winter from northeastern Mexico to Panama, and migrated north via the Gulf Coast of Mexico. While Louisiana birds overlapped with Central birds on their spring migratory routes along the Gulf Coast, we found that Louisiana birds had a more restricted wintering distribution in the Yucatan Peninsula and Central America. Further estimation of the straight‐line distance from the predicted breeding location to the wintering location revealed that individuals sampled at lower winter latitudes traveled to greater distances (i.e., the predicted breeding area was further north; p > .001), confirming that these species exhibit a leapfrog migration pattern. Overall, these results demonstrate the utility of a genoscape‐based approach for identifying range‐wide patterns of migratory connectivity such as leapfrog migration with a high degree of clarity.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Characterization of ambient polychlorinated biphenyl background conditions in surface waters of the Pajarito Plateau, New Mexico

Abstract This study presents the development of polychlorinated biphenyl (PCB) background threshold values (BTVs) that statistically characterize ambient background conditions for surface waters in undeveloped and developed landscapes of the Pajarito Plateau in the Rio Grande Basin of New Mexico. Between 2009 and 2018, surface water data were collected at 45 locations under a variety of flow conditions and regimes. A total of 163 samples were collected, with roughly 1/3 of samples and locations being in undeveloped areas (n = 53 from 17 locations), and the remainder being in developed areas (n = 110 from 28 locations). While there are areas on the Pajarito Plateau where PCB point sources are known or likely to have contributed to PCBs in soils, PCB BTVs calculated for undeveloped portions of watersheds (upstream of areas where PCB point sources are known or likely to have contributed to PCBs in soils, and therefore not affected by PCB sources within the watershed) are well above New Mexico's human health organism-only (HH-OO) water quality criterion (0.64 ng/L). Background threshold values are even higher in developed areas upstream of managed soil sites, suggesting that in developed areas, both diffuse ambient PCB sources (e.g., atmospheric deposition) and localized urban sources (e.g., building materials, paints, and electrical equipment) contribute to PCBs in those watersheds. These findings indicate that New Mexico's current HH-OO water quality criterion for PCBs cannot practicably be met due to ambient conditions. It is also impracticable to meet the US Environmental Protection Agency (EPA) criterion continuous concentration (CCC) of 14 ng/L in developed background areas, where the BTV is approximately 1.5 times the CCC. Integr Environ Assess Manag 2023;19:1307–1319. © 2022 SETAC

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

The use and abuse of cinnabar in Late Neolithic and Copper Age Iberia

Abstract In this study, total mercury (THg) was analyzed in archaeological human bone from 23 sites dating to between the Middle Neolithic and the Antiquity. A total of 370 individuals from individual or collective burials was sampled, mostly using cortical bone from the humerus. These individuals were recovered from over 50 different funerary structures ranging from tholoi, pits, caves, and hypogea. Although cinnabar (HgS) is a likely cause of mercury poisoning and toxicity for people exposed to this mineral from mining or use as a paint or pigment, not all sites investigated here had cinnabar associated with the burials or other excavated areas. We found unusual levels of THg in many of the sampled individuals that we assume were caused by exposure to cinnabar in life, and not by diagenetic processes or other exposures to mercury such as through diet, which would only cause negligible accumulation of THg in bone. Our data, based on the largest sampling ever undertaken on contamination of human bone through archaeological evidence, provide a baseline for additional research on cinnabar and its use in Prehistory. Moderate to high levels of THg in human bone are mainly associated with societies dating from the second half of the 4th to late 3rd millennia B.C. (Late Neolithic to Middle Chalcolithic) in southern Iberia. By the Late Chalcolithic and Early Bronze Age, the use of cinnabar decreased significantly and became minimal or absent. The use and abuse of cinnabar appears to have been pervasive throughout the above‐mentioned period and particularly between c. 2900–2300 B.C. This occurred in connection with the high symbolic and probably sacred value of the substance, which was sought after, traded, and extensively used in a variety of rituals and social practices.

Emslie, Steven D.↗
DOE OSTI2022

Super-Large-Scale Hierarchically Porous Films Based on Self-Assembled Eye-Like Air Pores for High-Performance Daytime Radiative Cooling

Metal-free polymer daytime radiative cooling coatings with hierarchical eye-like air pores are proposed and fabricated with a super-large-scale film-stretching method. The hierarchically porous film (HPF) can be further coated with polymethyl methacrylate (PMMA) micro-hemispheres, forming coated HPF (cHPF), which do not dramatically change the optical or thermal properties. The cHPF is slightly better with a lower solar absorptivity (2.4%) and a higher thermal emissivity over the atmospheric transparency window (90.1%). The low solar absorptivity is due to the strong scattering of the hierarchical eye-like air pores, while the molecular vibrations and the focusing effect of the PMMA micro-hemispheres contribute to the high emissivity. Further, an average mid-day temperature reduction of 7.92 °C is achieved relative to the air temperature, and the average cooling power reaches 116.0 W m -2 , which are much better than the cooling performances of the commercial cooling cushion. During the day, the cHPF-covered simulated building is up to 6.47 and 4.84 °C cooler than the ambient and the white painted counterpart, respectively. The film is durable and resistant to chemical etching, and very promising to use globally, especially in warm and tropical regions.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Toolpath generation for automated wind turbine blade finishing operations

Incorporating automation into wind turbine blade manufacturing is important for reducing costs to meet current offshore wind energy production goals in the United States. This work proposes a process for automating three operations in wind blade manufacturing: trimming to remove flashing left over after bonding two blade skins together, grinding to produce a desired leading-edge shape, and sanding to prepare the blade for bonding overlamination or adding paint to the surface. The majority of this work focuses on the toolpath generation. The algorithms were tested on a 5-m blade section, and the results were analyzed in terms of operation speed and accuracy. Finally, future work is discussed to improve the performance of the system.

17 WIND ENERGY↗
DOE OSTI2017

Laccase-Assisted Grafting of Acrylic Acid onto Lignin for its Recovery from Wastewater

The acrylic acid (AA) in the wastewater from paint manufacturing could be recovered by grafting to lignosulfonate in the presence of laccase and tert-butyl hydroperoxide (t-BHP). The low concentration of t-BHP did not inhibit the laccase activity, but improved the radical formation on lignin by laccase reaction, then initiated AA polymerization on lignin. The results showed laccase took a significant role for AA grafting to lignin. 94 % of AA could be polymerized on lignin by laccase/t-BHP, while only 32 % of AA was grafted on lignin with the same condition without laccase. The ratio of lignin to acrylic acid also affected AA recovery, and higher concentration of acrylic acid led to high recovery rate of AA. In this reaction system, the suitable range of temperature was 30–40 °C for the chemo-enzymatic reaction. The AA grafted on lignin could be precipitated by calcium ion and recovered.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Tuning Sugarcane Bagasse Biochar into a Potential Carbon Black Substitute for Polyethylene Composites

One of the most used carbonaceous materials by industry are carbon blacks, which have technological applications in polymeric composites, coatings and paints, electric and electrochemical devices. One drawback is that they are produced from fossil fuels. Although biochars are also carbonaceous materials some disadvantages like their larger particles size, high ash content and highly oxygenated surface must be overcome to enable their use as substitute of carbon blacks in composites. Sugarcane bagasse biochar was used to produce carbonaceous materials to substitute carbon blacks. Milling of biochar decreased particle size from several hundreds of micrometers to 100–500 nm and narrowed its size distribution. Chemical leaching reduced the inorganic compounds and ash content by almost 20%. Great advance was achieved when biochar was thermally annealed in alcohol vapor atmosphere which resulted in biochar-based material with very low oxygenated carbon species at particles surface and turned them hydrophobic. Almost no C–O/C=O and O–C=O peaks components were observed at the X-ray photoelectron spectroscopy spectrum. Reactive thermal annealing of the biochar based additive was a key procedure to obtain polyethylene composites (5% loading) with mechanical, thermal and colorimetric properties very close to the ones prepared with the carbon black from fossil fuels.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Analytical chemistry of nuclear material: case studies from Los Alamos National Laboratory

Presented here are three case studies that demonstrate the breadth of bulk actinide analytical chemistry at Los Alamos National Laboratory (LANL). This laboratory was established during the Manhattan Project and is still considered one of the premier analytical laboratories for special nuclear materials characterization around the globe. First, the analytical chemistry of 238 Pu is presented, showcasing the unique challenges of this high activity isotope. Next, the analysis of 241 AmO 2 is discussed from the perspective of supporting nascent production at LANL. Finally, the analytical chemistry support of the production of plutonium non-destructive assay standards is discussed. Furthermore these examples paint a picture of the analytical capabilities needed to meet the dynamic challenges of LANL’s nuclear programs.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗