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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

The X-Ray Spectrum of an Isolated Old Neutron Star

This grant supported the analysis of an ASCA observation of RXJ185635-3754. The data were obtained without problem, and the spectra showed what we expected. We have presented the data at a number of forums, and the final paper is in draft form and will be submitted to the ApJ in early 2000. The delay in publishing the final results are solely due to our desire to incorporate the ASCA data in a multi-wavelength context, along with other X-ray, EUV, and optical data.

Walter, Frederick M.↗
DOE OSTI2012

Plasmonic Based Sensing Using an Array of Au-Metal Oxide Thin Films

An optical plasmonic-based sensing array has been developed and tested for the selective and sensitive detection of H2, CO, and NO2 at a temperature of 500°C in an oxygen-containing background. The three element sensing array used Au nanoparticles embedded in separate thin films of yttria stabilized zirconia (YSZ), CeO2, and TiO2. A peak in the absorbance spectrum due to a localized surface plasmon resonance (LSPR) on the Au nanoparticles was monitored for each film during gas exposures and showed a blue shift in the peak positions for the reducing gases, H2 and CO, and a red shift for the oxidizing gas NO2. A more in-depth look at the sensing response was performed using the multivariate methods of principal component analysis (PCA) analysis and linear discriminant analysis (LDA) on data from across the entire absorbance spectrum range. Qualitative results from both methods showed good separation between the three analytes for both the full array and the Au-TiO2 sample. Quantification of LDA cluster separation using the Mahalanobis distance showed better cluster separation for the array, but there were some instances with the lowest concentrations where the single Au-TiO2 film had better separation than the array. A second method to quantify cluster separation in LDA space was developed using multidimensional volume analysis of the individual cluster volume, overlapped cluster volume and empty volume between clusters. Compared to the individual sensing elements, the array showed less cluster overlap, smaller cluster volumes, and more space between clusters, all of which were expected for improved separability between the analytes.

Environmental Molecular Sciences Laboratory↗
NASA NTRS1975

Errors in Hadamard spectroscopy or imaging caused by imperfect masks

An analysis is given of the errors in Hadamard spectroscopy that are caused by transparent slits in the mask being systematically wider or narrower than they should be. It is shown that if the input spectrum consists of a single line, the distorted spectrum that is actually calculated consists of this line plus four small blips. When the transparent slits are too wide, these blips are of equal height and the same sign with one pair surrounding the line and another pair 5isplaced a certain distance from it. When the slits are too narrow, the displaced blips have the same amplitude, but are negative. The response to an arbitrary input spectrum is then determined from this. The same method of analysis may also be used to handle other types of errors.

Tai, M. H.↗
DOE OSTI2016

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in Fourier-space

Here, we analyse the Baryon Acoustic Oscillation (BAO) signal of the final Baryon Oscillation Spectroscopic Survey (BOSS) data release (DR12). Our analysis is performed in Fourier-space, using the power spectrum monopole and quadrupole. The dataset includes 1 198 006 galaxies over the redshift range 0.2 < z < 0.75. We divide this dataset into three (overlapping) redshift bins with the effective redshifts z eff = 0.38, 0.51 and 0.61. We demonstrate the reliability of our analysis pipeline using N-body simulations as well as 1000 MultiDark-Patchy mock catalogues, which mimic the BOSS-DR12 target selection. We apply density eld reconstruction to enhance the BAO signal-to-noise ratio. By including the power spectrum quadrupole we can sep-arate the line-of-sight and angular modes, which allows us to constrain the angular diameter distance D A (z) and the Hubble parameter H ( z ) separately. We obtain two independent 1 : 6% and 1 : 5% constraints on D A (z) and 2.9% and 2.3% constraints on H(z) for the low (z eff = 0.38) and high (z eff = 0.61) redshift bin, respectively. We obtain two independent 1% and 0.9% constraints on the angular averaged distance D V (z), when ignoring the Alcock-Paczynski e ect. The detection significance of the BAO signal is of the order of 8σ (post-reconstruction) for each of the three redshift bins. Our results are in good agreement with the Planck prediction within CDM. This paper is part of a set that analyses the final galaxy clustering dataset from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. (2016) to produce the final cosmological constraints from BOSS.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Spread Spectrum Digital Communications Modeling in Electronic Warfare Modeling and Simulation Software

This artifact is an intern project poster. The subject matter is modeling spread spectrum digital communications in electronic warfare modeling and simulation software produced by National and Homeland Security. It contains images of communications coverage analysis from the software, link budget terms, and image depicting the Wireless Spectrum Communications (WSComm) underlay control channel (UCC), and an image of a filter bank multicarrier spread spectrum (FBMCSS) signal. INL National and Homeland Security Electronic Warfare Modeling and Simulation software (EWMSS) is capable of modeling several digital and analog signal types, but it does not currently support spread spectrum techniques such as filter bank multicarrier spread spectrum (FBMCSS). FBMCSS modeling requires "processing gain," which is not present in EWMSS' link budget. Wireless Spectrum Communications (WSComm) Underlay Control Channel (UCC), a product of INL, employs FBMCSS and is modeled in EWMSS for this project. This research shows that by manually accounting for FBMCSS processing gain, EWMSS calculates a link margin that is within 0.023 dB of a link margin in an existing WSComm link budget. These link margins were based on free space path loss, an ideal propagation model. EWMSS has the capability to include terrain and other sophisticated propagation models in its calculations, giving it the potential to provide realistic, location-specific models of WSComm UCC if processing gain is accounted for.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS2002

Method and apparatus for chemical and topographical microanalysis

A scanning probe microscope is combined with a laser induced breakdown spectrometer to provide spatially resolved chemical analysis of the surface correlated with the surface topography. Topographical analysis is achieved by scanning a sharp probe across the sample at constant distance from the surface. Chemical analysis is achieved by the means of laser induced breakdown spectroscopy by delivering pulsed laser radiation to the sample surface through the same sharp probe, and consequent collection and analysis of emission spectra from plasma generated on the sample by the laser radiation. The method comprises performing microtopographical analysis of the sample with a scanning probe, selecting a scanned topological site on the sample, generating a plasma plume at the selected scanned topological site, and measuring a spectrum of optical emission from the plasma at the selected scanned topological site. The apparatus comprises a scanning probe, a pulsed laser optically coupled to the probe, an optical spectrometer, and a controller coupled to the scanner, laser and spectrometer for controlling the operation of the scanner, laser and spectrometer. The probe and scanner are used for topographical profiling the sample. The probe is also used for laser radiation delivery to the sample for generating a plasma plume from the sample. Optical emission from the plasma plume is collected and delivered to the optical spectrometer so that analysis of emission spectrum by the optical spectrometer allows for identification of chemical composition of the sample at user selected sites.

Kossakovski, Dmitri A.↗
DOE OSTI2020

Retrieval of energy spectra for all flavours of neutrinos from core-collapse supernova with multiple detectors

ABSTRACT We present a new method by which to retrieve energy spectrum for all falvours of neutrinos from core-collapse supernova (CCSN). In the retrieval process, we do not assume any analytic formulas to express the energy spectrum of neutrinos but rather take a direct way of spectrum reconstruction from the observed data; the singular value decomposition algorithm with a newly developed adaptive energy-gridding technique is adopted. We employ three independent reaction channels having different flavour sensitivity to neutrinos. Two reaction channels, inverse beta decay on proton and elastic scattering on electrons, from a water Cherenkov detector such as Super-Kamiokande (SK) and Hyper-Kamiokande (HK), and a charged current reaction channel with Argon from the Deep Underground Neutrino Experiment (DUNE) are adopted. Given neutrino oscillation models, we iteratively search the neutrino energy spectra at the CCSN source until they provide the consistent event counts in the three reaction channels. We test the capability of our method by demonstrating the spectrum retrieval to a theoretical neutrino data computed by our recent three-dimensional CCSN simulation. Although the energy spectrum with either electron-type or electron-type antineutrinos at the CCSN source has relatively large error compared to that of other species, the joint analysis with HK + DUNE or SK + DUNE will provide precise energy spectrum of all flavours of neutrinos at the source. Finally, we discuss perspectives for improvements of our method by using neutrino data of other detectors.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2004

Observed Relationship Between Ion Energization and the Broadband ELF Spectrum

Many existing theories linking broadband ELF wave activity (BBELF) to ion energization and outflow are based on the gyro-resonant heating of ions. Recent studies on the properties of these broadband waves show that other mechanisms may be more relevant. Using data from the Polar satellite, we will present an analysis of the observed relationship between the broadband electric field spectrum and ion energization across the cusp, auroral oval, and polar cap.

Coffey, V. N.↗
DOE OSTI2014

Water vapor in the spectrum of the extrasolar planet HD 189733b. II. The eclipse

Spectroscopic observations of exoplanets are crucial to infer the composition and properties of their atmospheres. HD 189733b is one of the most extensively studied exoplanets and is a cornerstone for hot Jupiter models. In this paper, we report the dayside emission spectrum of HD 189733b in the wavelength range 1.1-1.7 μm obtained with the Hubble Space Telescope Wide Field Camera 3 (WFC3) in spatial scan mode. The quality of the data is such that even a straightforward analysis yields a high-precision Poisson noise-limited spectrum: the median 1σ uncertainty is 57 ppm per 0.02 μm bin. We also build a white-light curve correcting for systematic effects and derive an absolute eclipse depth of 96 ± 39 ppm. The resulting spectrum shows marginal evidence for water vapor absorption, but can also be well explained by a blackbody spectrum. However, the combination of these WFC3 data with previous Spitzer photometric observations is best explained by a dayside atmosphere of HD 189733b with no thermal inversion and a nearly solar or subsolar H{sub 2}O abundance in a cloud-free atmosphere. Alternatively, this apparent subsolar abundance may be the result of clouds or hazes that future studies need to investigate.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Validation of the DESI DR2 measurements of baryon acoustic oscillations from galaxies and quasars

The Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2) galaxy and quasar clustering data represents a significant expansion of data from Data Release 1 (DR1), providing improved statistical precision in baryon acoustic oscillation (BAO) constraints across multiple tracers, including bright galaxies, luminous red galaxies, emission line galaxies, and quasars. In this paper, we validate the BAO analysis of DR2. We present the results of robustness tests on the blinded DR2 data and, after unblinding, consistency checks on the unblinded DR2 data. All results are compared with those obtained from a suite of mock catalogs that replicate the selection and clustering properties of the DR2 sample. We confirm the consistency of DR2 BAO measurements with DR1 while achieving a reduction in statistical uncertainties due to the increased survey volume and completeness. The combined BAO precision, including both statistical and systematic errors, improves from ∼0.52% in DR1 to 0.30% in DR2—a factor of 1.7 gain. We assess the impact of analysis choices, including different data vectors (correlation function vs power spectrum), modeling approaches and systematics treatments, and an assumption of the Gaussian likelihood, finding that our BAO constraints are stable across these variations and assumptions with a few minor refinements to the baseline setup of the DR1 BAO analysis. We summarize a series of pre-unblinding tests that confirmed the readiness of our analysis pipeline, the final systematic errors, and the DR2 BAO analysis baseline. The successful completion of these tests led to the unblinding of the DR2 BAO measurements, ultimately leading to the DESI DR2 cosmological analysis, with their implications for the expansion history of the Universe and the nature of dark energy presented in the DESI key paper (companion paper).

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Measuring higher-order moments of neutron-time-of-flight data for cryogenic inertial confinement fusion implosions on OMEGA

Ion temperatures serve as an important diagnostic for inertial confinement fusion (ICF) implosions. In direct-drive ICF experiments on OMEGA, neutron-time-of-flight (nTOF) data are used to infer the ion temperature of the fusing plasma produced in the implosion experiment. The analysis of the nTOF data requires an assumption about the shape of the underlying source signal. Since the source nTOF signal is a near-replica of the neutron energy spectrum, an ideal Gaussian shape, corresponding to the neutron energy spectrum of a uniform temperature plasma, is routinely employed. However, spatial and temporal variations of the ion temperature in the plasma give rise to higher-order moments, which were first described by Munro [Nucl. Fusion 56, 036001 (2016)]. In this work, we show a simpler alternative analysis to derive moments of the neutron energy spectrum for a plasma with variations in ion temperature. We also present a revised analysis of measured nTOF signals that uses a model with an additional degree of freedom to take into account the effect of ion temperature variations on the shape of the spectrum. Compared to presently used nTOF analysis, the revised analysis yields on average ≈2× more accurate fits to the data and up to 15% higher ion temperatures for cryogenic experiments. As a result, we quantify the ion temperature inflation caused by radially symmetric fluid flows, which are present even in a symmetric implosion, and which serve as a lower bound on the ion temperature inflation in real implosions.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1990

Multiwavelength pyrometry to correct for reflected radiation

Computer curve fitting is used in multiwavelength pyrometry to measure the temperature of a surface in the presence of reflected radiation by decomposing its radiation spectrum. Computer-simulated spectra (at a surface temperature of 1000 K; in the wavelength region 0.3 to 20 microns; with a reflected radiation-source temperature of 700 to 2500 K; and reflector emissivity from 0.1 to 0.9) were generated and decomposed. This method of pyrometry determined the surface temperatures under these conditions to within 5 percent. The practicability of the method was further demonstrated by the successful analysis of a related problem--decomposition of the real spectrum of an infrared source containing two emitters to determine their temperatures.

Ng, Daniel L. P.↗
NASA NTRS1991

Analysis of pressure-broadened ozone spectra in the 3 micron region

This work involves the analysis of a series of McMath Fourier Transform Infrared (FTIR) spectra of ozone broadened by mixing with air (four different pressures), nitrogen (three pressures), or oxygen (three pressures). Each spectrum covers the region from 2396 to 4057 cm(-1). This study focused on the 3 sub nu sub 3 band in t 3000 to 3060 cm(-1). The band is analyzed by first dividing its region into small intervals containing a few well isolated absorption lines of reasonable intensity. Each of these small intervals is fit by multiple iterations of the nonlinear least squares program until residuals (the difference between calculated and observed spectrum, as a percent of the strongest intensity in the interval) are minimized to a reasonable value which corresponds to the noise level of the measured spectrum. Position, intensity, and half-width are recorded for later analysis. From the measured half-widths, a pressure broadening coefficient was determined for each absorption line. Pressure shifts were determined by comparing observed line positions in the spectra of the diluted ozone samples to tabulated line positions determined from spectra of pure gas samples. Comparisons to other work on ozone indicate that the broadening and shift coefficients determined in this study are consistent with those determined in other spectral regions.

Prochaska, Eleanor S.↗
DOE OSTI2018

Enhancing Phenotyping and Molecular Analysis of Plant Root System Using Ultrasound Aeroponic Technology

Abstract Several plant growth systems are available to enhance the observation of the root system (e.g., hydroponic and aeroponic plant growth systems, use of transparent soils, etc.). This article describes the use of the ultrasound aeroponic system (USAS) to treat and to enhance access to the root systems of various model plant and crop species (e.g., Arabidopsis thaliana , Medicago truncatula , soybean, etc.). This system is also compatible with short‐term (hr) and long‐term (days/weeks) biotic and abiotic treatments of plants. Upon treatment, the ease of access to the plant root system facilitates phenotyping (e.g., analysis of root architecture, establishment of root light spectrum using remote sensing technology), microscopic, molecular, and biochemical experiments. In addition, to facilitate functional genomic studies, we combined the use of the USAS with the hairy root transformation system to grow and observe transgenic roots on composite legume plants. © 2018 by John Wiley & Sons, Inc.

Pingault, Lise↗
DOE OSTI2017

Techno-economic analysis of hybrid PV/T systems for process heat using electricity to subsidize the cost of heat

Process heat applications make up a large potential market for renewable energy. Despite heating demand being approximately double that of electricity, relatively little work has been done to develop renewable energy for process heat applications. Concentrated solar thermal (CST) systems are capable of reaching temperatures necessary for industrial and commercial steam applications but are often overlooked due to the difficulty of competing with natural gas. Novel hybrid photovoltaic/thermal systems (PV/T) are capable of simultaneously generating electricity and heat. The electricity produced is of higher value and offsets the lifetime cost of the system by producing a cost savings to the facility, ultimately making solar heat competitive with natural gas, propane, coal, and other fuels. The design and economic feasibility of a dish concentrator PV/T (CPV/T) system utilizing a transmissive CPV array is explored through a techno-economic model including technical, financial, and geographical inputs. Through practical design choices, the levelized cost of heat (LCOH) is competitive with natural gas or could even be reduced to zero in some locations by factoring in the electricity savings from additional energy generated by the transmissive CPV module.

14 SOLAR ENERGY↗
DOE OSTI2018

NMR-based serum metabolomics study reveals a innovative diagnostic model for missed abortion

A missed abortion (MA) is an in-utero death of the embryo or fetus before the 20th week of gestation with retained products of conception. In order to discover novel biomarkers for MA, a {sup 1}H NMR spectroscopy-based metabolomics approach was applied to detect human MA serum metabolic profiles. Serum samples were obtained from patients with MA (n = 15) and healthy controls (n = 9) for study. The NOESYPR1D spectrum combined with multi-variate pattern recognition analysis was used to cluster the groups and establish a disease-specific metabolites phenotype. Principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) models were capable of distinguishing MA patients from healthy subjects. The results revealed that 24 metabolites altered in MA patients compared with the control population. Metabolomic pathway analysis demonstrated that alanine, aspartate and glutamate metabolism, citrate cycle (TCA cycle), taurine and hypotaurine metabolism were significantly altered in MA. The results indicated that serum NMR-based metabolomic profiling method is sensitive and specific enough to distinguish MA and from healthy controls, this method could be developed as a clinically useful diagnostic tool for MA. The finding from the MA serum metabolic profiling shed a new light on further understanding of MA disease mechanisms.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Hydrothermal synthesis and structural characterization of an organic–inorganic hybrid sandwich-type tungstoantimonate [Cu(en){sub 2}(H{sub 2}O)]{sub 4}[Cu(en){sub 2}(H{sub 2}O){sub 2}][Cu{sub 2}Na{sub 4}(α-SbW{sub 9}O{sub 33}){sub 2}]·6H{sub 2}O

An organic–inorganic hybrid sandwich-type tungstoantimonate [Cu(en){sub 2}(H{sub 2}O)]{sub 4}[Cu(en){sub 2}(H{sub 2}O){sub 2}][Cu{sub 2}Na{sub 4}(α-SbW{sub 9}O{sub 33}){sub 2}]·6H{sub 2}O (1) has been synthesized by reaction of Sb{sub 2}O{sub 3}, Na{sub 2}WO{sub 4}·2H{sub 2}O, CuCl{sub 2}·2H{sub 2}O with en (en=ethanediamine) under hydrothermal conditions and structurally characterized by elemental analysis, inductively coupled plasma atomic emission spectrometry, IR spectrum and single-crystal X-ray diffraction. 1 displays a centric dimeric structure formed by two equivalent trivacant Keggin [α-SbW{sub 9}O{sub 33}]{sup 9−} subunits sandwiching a hexagonal (Cu{sub 2}Na{sub 4}) cluster. Moreover, those related hexagonal hexa-metal cluster sandwiched tungstoantimonates have been also summarized and compared. The variable-temperature magnetic measurements of 1 exhibit the weak ferromagnetic exchange interactions within the hexagonal (Cu{sub 2}Na{sub 4}) cluster mediated by the oxygen bridges. - Graphical abstract: An organic–inorganic hybrid (Cu{sub 2}Na{sub 4}) sandwiched tungstoantimonate [Cu(en){sub 2}(H{sub 2}O)]{sub 4}[Cu (en){sub 2}(H{sub 2}O){sub 2}][Cu{sub 2}Na{sub 4}(α-SbW{sub 9}O{sub 33}){sub 2}]·6H{sub 2}O was synthesized and magnetic properties was investigated. Display Omitted - Highlights: • Organic–inorganic hybrid sandwich-type tungstoantimonate. • (Cu{sub 2}Na{sub 4} sandwiched) tungstoantimonate [Cu{sub 2}Na{sub 4}(α-SbW{sub 9}O{sub 33}){sub 2}]{sup 10−}. • Ferromagnetic tungstoantimonate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Synthesis and characterization of CuInS{sub 2} nanostructure by ultrasonic-assisted method and different precursors

Graphical abstract: Display Omitted Highlights: ► CuInS{sub 2} nanoparticles were synthesized by ultrasonic assisted method. ► CuInS{sub 2} nanoparticles obtained after annealing at 350 °C for 1 h. ► The effect of some parameters including ultrasonic was investigated. -- Abstract: This paper reports on the synthesis of CuInS{sub 2} nanostructure via an ultrasonic assisted method by employing different sulfur source. Morphology, structure and composition of the obtained products were characterized by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), scanning electron microscope (SEM), infrared (IR) spectrum, and photoluminescence (PL) spectroscopy. The effects of ultrasonic irradiation, power and time of irradiation, surfactant, and type of copper source were investigated.

36 MATERIALS SCIENCE↗