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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Ocean surface radiation measurement best practices

Ocean surface radiation measurement best practices have been developed as a first step to support the interoperability of radiation measurements across multiple ocean platforms and between land and ocean networks. This document describes the consensus by a working group of radiation measurement experts from land, ocean, and aircraft communities. The scope was limited to broadband shortwave (solar) and longwave (terrestrial infrared) surface irradiance measurements for quantification of the surface radiation budget. Best practices for spectral measurements for biological purposes like photosynthetically active radiation and ocean color are only mentioned briefly to motivate future interactions between the physical surface flux and biological radiation measurement communities. Topics discussed in these best practices include instrument selection, handling of sensors and installation, data quality monitoring, data processing, and calibration. It is recognized that platform and resource limitations may prohibit incorporating all best practices into all measurements and that spatial coverage is also an important motivator for expanding current networks. Thus, one of the key recommendations is to perform interoperability experiments that can help quantify the uncertainty of different practices and lay the groundwork for a multi-tiered global network with a mix of high-accuracy reference stations and lower-cost platforms and practices that can fill in spatial gaps.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Improving helium abundance determinations with Leo P as a case study

Currently, the primordial helium abundance is best estimated through spectroscopic observations of H II regions in metal-poor galaxies. However these determinations are limited by several systematic uncertainties which ultimately limit our ability to accurately ascertain the primordial abundance. In this study, we improve the methodologies for solving for the reddening, the emission contributions from collisional excitation of the H I atoms, the effects underlying absorption in the H I and He I emission lines, and the treatment of the blended H I and He I emission at λ3889 with the aim of lowering the systematic uncertainties in helium abundance determinations. To apply these methods, we have obtained observations of the He I λ10830 emission line in the brightest H II region in the extremely metal-poor (3% Z ⊙ ) galaxy Leo P with the LUCI1 instrument on the LBT. We combine this measurement with previous MODS/LBT observations to derive an improved helium abundance. In doing so, our present analysis results in a decrease in the uncertainty in the helium abundance of Leo P by approximately 70%. Furthermore, this result is combined with data from other observations to estimate the primordial helium mass fraction, Yp= 0.2453 ± 0.0034.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

DESI peculiar velocity survey – Fundamental Plane

The Dark Energy Spectroscopic Instrument (DESI) peculiar velocity survey aims to measure the peculiar velocities of early- and late-type galaxies within the DESI footprint using both the Fundamental Plane and optical Tully–Fisher relations. Direct measurements of peculiar velocities can significantly improve constraints on the growth rate of structure, reducing uncertainty by a factor of approximately 2.5 at redshift 0.1 compared to the DESI Bright Galaxy Survey’s redshift space distortion measurements alone. We assess the quality of stellar velocity dispersion measurements from DESI spectroscopic data. These measurements, along with photometric data from the Legacy Survey, establish the Fundamental Plane relation and determine distances and peculiar velocities of early-type galaxies. During survey validation, we obtain spectra for 6698 unique early-type galaxies, up to a photometric redshift of 0.15. 64 per cent of observed galaxies (4267) have relative velocity dispersion errors below 10 per cent. This percentage increases to 75 per cent if we restrict our sample to galaxies with spectroscopic redshifts below 0.1. We use the measured central velocity dispersion, along with photometry from the DESI Legacy Imaging Surveys, to fit the Fundamental Plane parameters using a 3D Gaussian maximum likelihood algorithm that accounts for measurement uncertainties and selection cuts. In addition, we conduct zero-point calibration using the absolute distance measurements to the Coma cluster, leading to a value of the Hubble constant, H 0 = 76.05 ± 0.35 (statistical) ±0.49 (systematic Fundamental Plane) ±4.86 (statistical due to calibration) km s –1 Mpc –1 ⁠. This H 0 value is within 2σ of Planck cosmic microwave background results and within 1σ of other low-redshift distance indicator-based measurements.

cosmological parameters↗
DOE OSTI2024

Search for photons above 10 18 eV by simultaneously measuring the atmospheric depth and the muon content of air showers at the Pierre Auger Observatory

The Pierre Auger Observatory is the most sensitive instrument to detect photons with energies above 1 0 17 eV . It measures extensive air showers generated by ultrahigh energy cosmic rays using a hybrid technique that exploits the combination of a fluorescence detector with a ground array of particle detectors. The signatures of a photon-induced air shower are a larger atmospheric depth of the shower maximum ( X max ) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced cascades. In this work, a new analysis technique in the energy interval between 1 and 30 EeV ( 1 EeV = 1 0 18 eV ) has been developed by combining the fluorescence detector-based measurement of X max with the specific features of the surface detector signal through a parameter related to the air shower muon content, derived from the universality of the air shower development. No evidence of a statistically significant signal due to photon primaries was found using data collected in about 12 years of operation. Thus, upper bounds to the integral photon flux have been set using a detailed calculation of the detector exposure, in combination with a data-driven background estimation. The derived 95% confidence level upper limits are 0.0403, 0.01113, 0.0035, 0.0023, and 0.0021 km − 2 sr − 1 yr − 1 above 1, 2, 3, 5, and 10 EeV, respectively, leading to the most stringent upper limits on the photon flux in the EeV range. Compared with past results, the upper limits were improved by about 40% for the lowest energy threshold and by a factor 3 above 3 EeV, where no candidates were found and the expected background is negligible. The presented limits can be used to probe the assumptions on chemical composition of ultrahigh energy cosmic rays and allow for the constraint of the mass and lifetime phase space of super-heavy dark matter particles. Published by the American Physical Society 2024

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Measurements of Non-Maxwellian Electron Distribution Functions and Their Effect on Laser Heating

Electron velocity distribution functions driven by inverse bremsstrahlung heating are measured to be non-Maxwellian using a novel angularly resolved Thomson-scattering instrument and the corresponding reduction of electrons at slow velocities results in a ~40% measured reduction in inverse bremsstrahlung absorption. The distribution functions are measured to be super-Gaussian in the bulk (v/v th < 3) and Maxwellian in the tail (v/v th > 3) when the laser heating rate dominates over the electron-electron thermalization rate. Furthermore, simulations with the particle code quartz show the shape of the tail is dictated by the uniformity of the laser heating.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Ronchi shearing interferometry for wavefronts with circular symmetry

Ronchi testing of a focused electromagnetic wave has in the last few years been used extensively at X-ray free-electron laser (FEL) facilities to qualitatively evaluate the wavefront of the beam. It is a quick and straightforward test, is easy to interpret on the fly, and can be used to align phase plates that correct the focus of aberrated beams. In general, a single Ronchigram is not sufficient to gain complete quantitative knowledge of the wavefront. However the compound refractive lenses that are commonly used at X-ray FELs exhibit a strong circular symmetry in their aberration, and this can be exploited. Furthermore, a simple algorithm that uses a single recorded Ronchigram to recover the full wavefront of a nano-focused beam, assuming circular symmetry, is presented, and applied to experimental measurements at the Matter in Extreme Conditions instrument at the Linac Coherent Light Source.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Normality of I-V Measurements Using ML

There is an increased interest in instrument-computing ecosystems (ICEs) that support science workflows empowered by AI-automated experiments and computations in diverse areas. In particular, electrochemistry ICEs are promising for accelerating the design and discovery of electrochemical systems for energy storage and conversion, by automating significant parts of workflows that combine synthesis and characterization experiments with computations. They require the integration of flow controllers, solvent containers, pumps, fraction collectors, and potentiostats, all connected to an electrochemical cell, as illustrated in Fig. 1. These are specialized instruments with custom software that is not originally designed for network integration. We developed network and software solutions for electrochemical workflows that adapt system and instrument settings in real-time for multiple rounds of experiments. In particular, we developed Python wrappers for Application Programming Interfaces (APIs) of instrument commands and Pyro client-server modules that enable them to be executed from remote computers. The entire workflow is orchestrated by a Jupyter notebook running on a remote computer.

Al Najjar, Anees↗
DOE OSTI2023

Structure-mechanical properties correlation in bulk LiPON glass produced by nitridation of metaphosphate melts

The glassy solid electrolyte Lithium phosphorous oxynitride (LiPON) has been widely researched in thin film solid state battery format due to its outstanding stability when cycled against lithium. In addition, recent reports show thin film LiPON having interesting mechanical behaviors, especially its ability to resist micro-scale cracking via densification and shear flow. Here, in the present study, we have produced bulk LiPON glasses with varying nitrogen contents by ammonolysis of LiPO 3 melts. The resulting compositions were determined to be LiPO 3-3z/2 N z , where 0 ≤ z ≤ 0.75, and the z value of 0.75 is among the highest ever reported for this series of LiPON glasses. The short-range order structures of the different resulting compositions were characterized by infrared, Raman, 31 P magic angle spinning nuclear magnetic resonance, and X-ray photoelectron spectroscopies. Instrumented nano-indentation was used to measure mechanical properties. It was observed that similar to previous studies, both trigonally coordinated (N t ) and doubly bonded (N d ) N co-exist in the glasses in about the same amounts for z ≤ 0.36, the limit of N content in most previous studies. For glasses with z > 0.36, it was found that the fraction of the N t increased significantly while the fraction of N d correspondingly decreased. The incorporation of nitrogen increased both the elastic modulus and hardness of the glass by approximately a factor of 1.5 when N/P ratio reaches 0.75. At the same time, an apparent embrittlement of the glass was observed due to nitridation, which was revealed by nanoindentation with an extra sharp nanoindenter tip.

25 ENERGY STORAGE↗
DOE OSTI2023

Passive methods for spent fuel characterisation at the Finnish geological repository

Development of the Passive Gamma Emission Tomography (PGET) and Passive Neutron Albedo Reactivity (PNAR) methods in the context of the Finnish geological repository for spent nuclear fuel has shown that they provide, for BWR fuel assemblies, the comprehensive verification needed to meet the nuclear safeguards objectives of the repository. The principles of the PGET and PNAR methods and the design and operation of the respective instruments are presented. A few results from measurements at the spent fuel storage pools at the Finnish nuclear power plants are discussed. The directions of ongoing and future developments are indicated.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2020

Sonic Detection and Ranging (SODAR) Wind Profiler Instrument Handbook

The SODAR (Sonic Detection and Ranging) wind profiler measures wind profiles and backscattered signal strength between (nominally) 15 meters (m) and 500 m. It operates by transmitting acoustic energy into the atmosphere and measuring the strength and frequency of backscattered energy. The strength of the backscattered signal is determined by the strength of temperature inhomogeneities with size on the order of 10 centimeters (cm). Assuming the scattering elements in the atmosphere are moving with the mean wind, the horizontal wind field can be derived. The U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Mobile Facility (AMF) has a system developed by Scintec, Inc. that transmits a sequence of frequencies to enhance signal determination.

17 WIND ENERGY↗
DOE OSTI2020

Literature Review of Thermomechanical Analysis, Its Instrument Components and Applications

Thermomechanical analysis (TMA) is used to measure the dimensional changes in a sample as a function of temperature. TMA allows for several modes of analysis, with expansion and compression being the most common. TMA is based on the theory of dilatometry and relies on the fact that polymers are viscoelastic materials, possessing both viscous and elastic properties. TMA yields information about the thermal effects on a polymer such as shrinkage, expansion, softening, melting, glass transition temperature and allows for the calculation of the coefficient of thermal expansion (CTE), which can be useful for many applications of polymers.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Literature Review of Thermomechanical Analysis, Its Instrument Components and Applications

Thermomechanical analysis (TMA) is used to measure the dimensional changes in a sample as a function of temperature. TMA allows for several modes of analysis, with expansion and compression being the most common. TMA is based on the theory of dilatometry and relies on the fact that polymers are viscoelastic materials, possessing both viscous and elastic properties. TMA yields information about the thermal effects on a polymer such as shrinkage, expansion, softening, melting, glass transition temperature and allows for the calculation of the coefficient of thermal expansion (CTE), which can be useful for many applications of polymers.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Pyrolysis Modeling of PMMA decomposition studied by TGA

Data from four TGA experiments conducted at Sandia National Laboratories was used for determination of a pyrolysis model using a commercial thermokinetics program developed by Netzsch Instruments (Kinetics NEO, version 2.1). The data measured at 1 K/min and the average of three measurements at 50 K/min were used as input into Kinetics NEO. The model was developed using data in the range 373 to 773 K. An initial estimate of the energy of activation (E) and pre-exponential constant (A) were determined from the model-free Friedman approach.

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

Measurement of Plutonium Ratios for CRM 137A Recertification

This report documents the analytical methodologies used by the Chemical and Isotopics Mass Spectrometry (CIMS) Group at the US Department of Energy’s Oak Ridge National Laboratory (ORNL) for plutonium isotopic ratio characterizations on purified ~1 mg units prepared by Lawrence Livermore National Laboratory (LLNL) from a mother solution created from an existing 250 mg unit of certified reference material (CRM) 137. The analytical processes described are designed to maintain traceability of the final certified attributes and to eliminate sources of systematic bias for the measurements described. The measurands for certification are the plutonium isotope ratios: 238 Pu/ 239 Pu, 240 Pu/ 239 Pu, 241 Pu/ 239 Pu, and 242 Pu/ 239 Pu. The preparation and analytical process included the following activities: Preparation of reference materials to be used as calibrants to establish traceability to the SI unit of mass for the isotopic analyses and quality controls. For the plutonium isotopic analyses, CRM 128 (a CRM comprising equal atoms of 239 Pu and 242 Pu) was used as the primary calibrant; Each CRM 137A unit was reconstituted using dilute high-purity HNO3. From each, seven replicates were distributed for the isotopic characterizations by thermal ionization mass spectrometry (TIMS) using the total evaporation (TE) method for isotope ratio measurements and MC-ICP-MS using a dynamic peak hooping method for secondary isotope ratio measurements; Due to time delay in the analyses from the last purification of the original CRM 137 mother solution by LLNL, an aliquot of the three provided plutonium units was purified using Eichrom TEVA separation methods to remove americium in-growth and uranium impurities; Minimally corrected data were reported from each analysis using reporting templates provided by the New Brunswick Laboratory Program Office (NBL PO) for the specific methods used for isotopic measurements. In addition, a copy of the instrument exports, Excel templates for isotopic data corrections, and the uncertainty budgets completed with the GUM Workbench software package were submitted to NBL PO.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2024

Calibrator for Airborne Aerosol Probes (CAAP) Field Campaign Report

In this campaign, Calibrator for Airborne Aerosol Probes (CAAP), Mesa Photonics provided its U.S. Department of Energy (DOE) Small Business Innovation Research (SBIR) Phase II prototype of a portable, battery-powered monodisperse aerosol/droplet generator to field-calibrate two aerosol/cloud characterization instruments deployed on the DOE Atmospheric Radiation Measurement (ARM) Aerial Facility (AAF) ArcticShark uncrewed aerial system (UAS) during the flight campaign conducted at ARM’s Southern Great Plains (SGP) atmospheric observatory and the Blackwell-Tonkawa airfield (Oklahoma) in May 2024. The CAAP campaign (May 20-24, 2024) partially overlapped with the main ARM AAF campaign, Turbulent Layers Promoting New Particle Formation (NPFTURBULENCE, May 7-27, 2024, Gannet Hallar, principal investigator). The main goal of the CAAP campaign was field validation of calibration of aerosol and cloud probes deployed on the ArcticShark UAS. The campaign also provided an opportunity to test and evaluate the Mesa Photonics’ monodisperse aerosol/droplet generator prototype in the field, under real-life operational conditions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Radioactivity-in-materials lead for nEXO (Final Scientific Report)

Abstract, introduction, and summary of work completed and products produced by DOE award SC002466. Primary products were six peer-reviewed publications and two PhD theses. This award also supported the operation of an underground HPGe detector and several radioassay measurements: one in a stand alone publication in Phys. Rev. C and the others in an upcoming nEXO radioassay summary paper. The nEXO collaboration aims to demonstrate the Majorana nature of the neutrino by observing the neutrinoless double-beta decay of 136 Xe with a next-generation experiment. The University of Kentucky nEXO group (UKY) operates a world-leading ultra-low-background γ-ray spectrometer as part of the nEXO radioactive background control R&D effort. The nEXO project is a proposed ton-scale neutrinoless double-beta decay experiment. The UKY PI is leading the radioactivity content assessment for all materials required by the nEXO project. As a subset of this task, UKY is also responsible for project-wide management of all low-background γ-ray spectrometry measurements; material assays with these types of instruments, together with ICP-MS, neutron-activation-analysis, and α-spectrometry, are critical to ensuring that the nEXO project can achieve its design sensitivity

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

Wind lidar operations and observations from Tundra Pigeon

Lawrence Livermore National Laboratory brought a ZX-300 profiling lidar to the Tundra Pigeon experiment for the purpose of collecting wind measurements in the lower atmospheric boundary layer. The ZX-300 lidar is a portable Doppler lidar which uses light to track naturally occurring aerosols across a measurement cone, thereby deriving wind speed (horizontal and vertical) and wind direction. The ZX-300 is programable between the heights of 10 m and 300 m above ground level and additionally has a 1 m onboard meteorological sensor for collecting measurements of air temperature, relative humidity, air pressure and wind at 1 m height. We programmed the ZX-300 to target altitudes of most interest to the tracer experiment. These heights were 10, 15, 20, 30, 38, 50, 75, 100, 125, 150 and 200 m. Note that the 38 m level is a fixed calibration height and cannot be changed. This measurement strategy prioritized winds close to the surface while ensuring that we’d also collect information about the winds aloft. The wind measurements are collected directly over the lidar instrument and represent a vertical profile of the winds over that location. However, given that there were minimal terrain and vegetation differences in the area, we’d expect these wind conditions to be representative of a larger volume area, discussed in more detail below.

54 ENVIRONMENTAL SCIENCES↗