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All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Organic geochemistry of sediments from the continental margin off southern New England, U.S.A.--Part II. Lipids

Organic geochemical measurements of the lipid fraction, comparing saturated and aromatic hydrocarbons, fatty acids, alcohols and sterols, have been carried out on six sediments cores collected from the Atlantic shelf, slope and the rise areas to evaluate the cross-shelf transport of the organic carbon. The concentration of most of the organic compound classes studied is correlated with the total organic carbon, which decreases from the shelf through slope to the rise. Terrigenous carbon is recognizable even in the slope and rise sediments, but terrestrial influx decreases relative to marine generated lipids in the slope and rise organic matter. We estimate that approximately 50% of the shelf organic matter is exported to the slope. Data of sediment trap material collected at 1200 m from 1250 m water depth are discussed and compared with that of surface sediment from 1280 m water depth (slope). Fluxes for specific organic compound classes have been computed. The fluxes are of the same magnitude as for equatorial North Atlantic trap particulates at comparable water depth, studied by other investigations.

NASA Discipline Exobiology↗
NASA NTRS1971

Global distribution of total ozone derived from Nimbus 3 satellite during April July, 1969 and its implication to upper tropospheric circulation

Utilizing a stepwise multiple regression scheme, monthly mean global maps of total ozone are produced from the spectral intensity measurements made by the infrared interferometer spectrometer (IRIS) onboard the Nimbus 3 satellite for the period April 18 to July 22, 1969. These maps show that over the equatorial regions total ozone increases steadily from April to July. Further, latitudinal variation of total ozone derived from these maps shows that the ozone increases at all latitudes over the Southern Hemisphere uniformly from April to July while over the Northern Hemisphere the monthly decrease at all latitudes is nonuniform. In general, these maps bear a close resemblance to the upper tropospheric circulation. It is observed that the total ozone is best correlated with the 200 mb geopotential heights. This relationship enables the utilization of total ozone as a quasi-stream function to determine geostrophic winds at 200 mb level. Further, even at low latitudes where the total ozone does not bear simple relationship to the geopotential heights the course of the easterly jet stream with the help of the ozone measurements can be identified.

Prabhakara, C.↗
NASA NTRS1988

The determination of ultraviolet extinction from the optical and near-infrared

The correlation of optical-near-infrared photometry for a sample of stars with well-determined ultraviolet extinction is examined. A good correlation is found; in particular, it is found that the value of total-to-selective extinction correlates well with the level of linear UV background extinction found from the UV curve parameterization of Fitzpatrick and Massa. An analytic expression is given for an improved estimate for the UV extinction law that can be obtained from optically determined values of R. For R values outside the range R = 3.1 -3.5, use of the analytic expressions given here will result in a more accurate representation of the applicable UV extinction than using the standard techniques of assuming the average curve or 'ironing out' the bump.

Cardelli, Jason A.↗
DOE OSTI2019

Learning from Five-year Resource-Utilization Data of Titan System

Titan was the flagship supercomputer at the Oak Ridge Leadership Computing Facility (OLCF). It was deployed in late 2012, became the fastest supercomputer in the world and was retired on August 2, 2019. With Titan's mission complete, this paper provides a first-order examination of the usage of its critical resources (CPU, Memory, GPU, and I/O) over a five-year production period (2015-2019). In particular, we show quantitatively that the majority of CPU time was spent on the large-scale jobs, which is consistent with the policy of driving ground-breaking science through leadership computing. We also corroborate the general observation of the low CPU-memory usage with 95% jobs utilizing only 15% or less available memory. Additionally, we correlate the increase of total job submissions and the decrease of GPU-enabled jobs during 2016 with the GPU reliability issue which impacted the large-scale runs. We further show the surprising read/write ratio over the five-year period, which contradicts the general mindset of the large-scale simulation machines being “write-heavy”. This understanding will have potential impact on how we design our next-generation large-scale storage systems. We believe that our analyses and findings are going to be of great interest to the high-performance computing (HPC) community at large.

Wang, Feiyi↗
NASA NTRS1973

Turbulence measurements in a compressible boundary layer subjected to a shock-wave-induced adverse pressure gradient.

The rms intensities of fluctuating mass flux and total temperature and their correlation coefficients are given for the case of an adiabatic, Mach 4, axisymmetric shock-wave boundary-layer interaction. Data were obtained upstream, within, and downstream of the interaction by the use of constant temperature hot-wire anemometer. Turbulence spectra and quantitative behavior from oscilloscope traces are shown at selected locations. The measurements indicate that certain frequencies of the turbulence are increased as a result of the interaction and that the mass flux and total temperature fluctuations remain highly correlated over most of the boundary layer throughout the interaction. The present data are also transformed to rms intensities of fluctuating static temperature and velocity and compared with existing data obtained in adiabatic flows.

Rose, W. C.↗
NASA NTRS1987

Photochemical ozone overburden correction

One-half of the total ozone column is predominantly under photochemical control under all conditions except polar winter. The other half is dynamically controlled. Since the photochemical forcing is phased with the solar declination and modulated by air temperature variation in the upper stratosphere and the dynamic forcing is tied to wave activity in the upper troposphere, the total ozone column is a mixture of the two drivers. If the total ozone is used to infer a property of the dynamic field, namely the tropopause height, it is necessary to correct for the photochemical variations. It should be possible to remove the photochemical component of the total ozone by using SBUV profile information along the orbital track as long as the spatial variations are low frequency. The column integral above the Umkehr levels in the lower stratosphere are examined to determine the level where the spatial variability decreases to the expected photochemical range to find an approximate dividing line between photochemical and dynamic control. Given this a spherical harmonic function will be fitted to the ozone field and subtracted from the TOMS total ozone field. This residual field will then be correlated with tropopause height to determine whether an improvement is obtained over the total ozone correlation.

Stefanick, Michael↗
NASA NTRS1983

The diffuse interstellar feature at 4430 A and interstellar extinction in the far-ultraviolet

IUE measurements have been obtained for the UV extinction characteristics of 20 reddened stars previously reported to have anomalously high or low A(4430)/E(B-V) ratios, in order to conduct a first statistical study of the correlations between these ratios and interstellar extinction features in the UV. A marginally significant positive correlation is noted between A(4430)/E(B-V) and the normalized strength of the 2175 A extinction jump, but no correlation is found with the total extinction at the wavelength and a marginally negative correlation is found with the extinction rise at 1250 A. The hypothesis that 4430 A diffuse absorption is produced by very small interstellar grains is not supported by the present observations.

Witt, A. N.↗
DOE OSTI2020

Nondestructive measurements of residual 235 U mass of Israeli Research Reactor-1 fuel using the Advanced Experimental Fuel Counter

In 2018, a measurement campaign took place with participants from Los Alamos National Laboratory (LANL), the Nuclear Research Centre-Negev (NRCN) and Soreq Nuclear Research Center (SNRC) at the Israeli Research Reactor-1 (IRR-1) in which 14 of the reactor’s used fuel assemblies (FAs) with varied amount of depletion were measured with the nondestructive assay instrument Advanced Experimental Fuel Counter (AEFC). Designed for safeguards purposes, the AEFC measures both neutrons emitted from the FA (passive neutrons) and fission neutrons induced by an external neutron source (in this experiment, 252 Cf). Signals recorded with the AEFC include total neutron count rates (Singles), time-correlated neutron count rates (Doubles), and total gamma-ray count rates. The 235 U content of the FAs was previously assessed by two independent methods: (1) measurement of the transparency of the FA to low-energy gamma rays from an activated rhenium source (rhenium gamma transmission, or the RGT method) and (2) calculation of the 30-year burnup history of the core using detailed three-dimensional Monte-Carlo core depletion calculations. The results from the FAs that had been measured via the RGT method were used to construct the calibration curves, which translate the AEFC count rates to 235 U mass. Then, the calibration was evaluated using AEFC measurements of six additional FAs that were not measured via the RGT method. From the results, it was determined the Doubles calibration curve was more reliable than that of the Singles and follows a simple second-order polynomial fit for the whole range of residual 235 U mass content, albeit with larger statistical uncertainty. Detailed uncertainties quantification was conducted for both the AEFC Singles and Doubles. This includes the analysis of statistical uncertainties, calibration uncertainty, and random uncertainties due to the sensitivity of the AEFC to several sources of uncertainty, namely the FA position, FA orientation, interrogation source position, and ambient pool temperature. Finally, an overall total uncertainty of 6 g of 235 U is estimated for the Singles and Doubles, which is mainly due to calibration uncertainty (for the Singles) and statistical uncertainty (for the Doubles), and which constitutes 3%–6% of the 235 U total mass in the FAs, depending on their level of depletion.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1994

Long-term ozone and temperature correlations above SANAE, Antarctica

A significant decline in Antarctic total column ozone and upper air temperatures has been observed in recent years. Furthermore, high correlations between monthly mean values of ozone and stratospheric temperature have been measured above Syowa, Antarctica. For the observations reported here, data from TOMS (Total Ozone Mapping Spectrometer) aboard the Nimbus 7 satellite have been used to examine the 1980 to 1990 decrease in total column ozone above the South African Antarctic base of SANAE (70 deg 18 min S, 2 deg 21 min W). The cooling of the Antarctic stratosphere above SANAE during this period has been investigated by examining upper air temperatures at the 150, 100, 70, 50, and 30 hPa levels obtained from daily radiosonde balloon launches. Furthermore, these two data sets have been used to examine long-term, medium-term, and short-term correlations between total column ozone and the temperatures at each of the five levels. The trend in SANAE total column ozone has been found to be -4.9 DU/year, while upper air temperatures have been found to decrease at around 0.3 C/year. An analysis of monthly average SANAE total column ozone has shown the decrease to be most severe during the month of September with a trend of -7.7 DU/year. A strong correlation (r(exp 2) = 0.92) has been found between yearly average total column ozone and temperature at the 100 hPa level. Daily ozone and temperature correlations show high values from September to November, at a time when the polar vortex is breaking down.

Bodeker, Gregory E.↗
NASA NTRS1980

The solar wind-magnetosphere energy coupling and magnetospheric disturbances

Energy coupling between the solar wind and the magnetosphere is examined and the influence of this coupling on magnetospheric disturbances is discussed. Following a review of the components of the total energy production rate of the magnetosphere and progress in the study of solar wind-magnetosphere correlations, the derivation of the solar wind-magnetosphere energy coupling function, which has been found to correlate well with the total magnetospheric energy production rate, is presented. Examination of the relations between the energy coupling function and the type of magnetic disturbance with which it is associated indicates that magnetic storms with a large sudden storm commencement and a weak main phase are associated with small energy coupling, while values of the coupling function greater than 5 x 10 to the 18th to 10 to the 19th erg/sec are required for the development of a major geomagnetic storm. The magnetospheric substorm is shown to be a direct result of increased solar wind-magnetosphere energy coupling rather than the sudden conversion of stored magnetic energy. Finally, it is indicated that at energy couplings greater than 10 to the 19th erg/sec, the positive feedback process responsible for substorms breaks down, resulting in the abnormal growth of the ring current.

Akasofu, S.-I.↗
NASA NTRS1975

Fine structure of 25 extragalactic radio sources

Interferometric observations taken at 7.8 GHz (gamma approximately = 3.8 cm) with five pairings of antennae of 25 extragalactic radio sources between April, 1972 and May, 1973 are reported. These sources exhibit a broad variety of fine structure from very simple to complex. The total flux and the correlated flux of some of the sources underwent large changes in a few weeks, while the structure and total power of others remained constant during the entire period of observation. Some aspects of the data processing and a discussion of errors are presented. Numerous figures are provided and explained. The individual radio sources are described in detail.

Wittels, J. J.↗
NASA NTRS2024

The Atacama Cosmology Telescope: Galactic Dust Structure and the Cosmic PAH Background in Cross-correlation with WISE

We present a cross-correlation analysis between 1ʹ resolution total intensity and polarization observations from the Atacama Cosmology Telescope (ACT) at 150 and 220 GHz and 15ʺ mid-infrared photometry from the Wide-field Infrared Survey Explorer (WISE) over 107 12°.5 × 12°.5 patches of sky. We detect a spatially isotropic signal in the WISE×ACT TT cross-power spectrum at 30σ significance that we interpret as the correlation between the cosmic infrared background at ACT frequencies and polycyclic aromatic hydrocarbon (PAH) emission from galaxies in WISE, i.e., the cosmic PAH background. Within the Milky Way, the Galactic dust TT spectra are generally well described by power laws in ℓ over the range 10 3 < ℓ < 10 4 , but there is evidence both for variability in the power-law index and for non-power-law behavior in some regions. We measure a positive correlation between WISE total intensity and ACT E-mode polarization at 1000 < ℓ ≲ 6000 at >3σ in each of 35 distinct ∼100 deg 2 regions of the sky, suggesting that alignment between Galactic density structures and the local magnetic field persists to subparsec physical scales in these regions. The distribution of TE amplitudes in this ℓ range across all 107 regions is biased to positive values, while there is no evidence for such a bias in the TB spectra. This work constitutes the highest-ℓ measurements of the Galactic dust TE spectrum to date and indicates that cross-correlation with high-resolution mid-infrared measurements of dust emission is a promising tool for constraining the spatial statistics of dust emission at millimeter wavelengths.

Rodrigo Córdova Rosado↗
DOE OSTI2020

Cause and impact of low-frequency chirping modes in DIII-D hybrid discharges

Significant variations in MHD activity and fast-ion transport are observed in the DIIID high-beta, steady-state hybrid discharges with a mixture of Electron Cyclotron (EC) waves and Neutral Beam Injection (NBI). When Electron Cyclotron Heating (ECH) or Current Drive (ECCD) is applied, Alfven Eigenmodes (AEs) are usually suppressed and replaced by low-frequency bursting modes. The analysis of a recently compiled database of hybrid discharges suggests that the change of the fast-ion pressure especially the perpendicular pressure is the main factor responsible for the instability transition. The lower ratio of fast-ion injection speed v inj to Alfven speed v alfven and slight drop of safety factor q min during ECCD may also facilitate the transition. The database shows that AEs mainly occur when the fast-ion fraction P f /P total is less than 0.53 and v inj /v alfven is greater than 0.50, while low-frequency bursting modes appear in the opposite regime. In this research, P f and P total are the central fast-ion pressure from classical prediction and total plasma pressure, respectively. The reason why the instability transition correlates with P f /P total and v inj /v alfven is that they can significantly modify the drive of low-frequency bursting modes and AEs. The explanation is supported by the observation that low-frequency bursting modes are rarely seen in the hybrids with NBI only, with EC waves and counter-NBI, or with high plasma density. A careful check of the low-frequency bursting modes suggests that they are mainly chirping (neoclassical) tearing modes [referred to as chirping (N)TM], i.e. the mode frequency firstly jumps up from the steady (N)TM frequency, then chirps down, and finally returns to the steady (N)TM frequency. Sometimes, the (N)TMs are fully stabilized and replaced with pure fishbones. Lastly, the resonance condition calculation and ’Kick’ model simulations suggest that (N)TMs and fishbones can interact through modification of the fast ion distribution in phase space, which influences the drive.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

COOL-LAMPS. VII. Quantifying Strong-lens Scaling Relations with 177 Cluster-scale Strong Gravitational Lenses in DECaLS

Abstract We estimate the Einstein-radius-enclosed total mass for 177 cluster-scale strong gravitational lenses identified by the ChicagO Optically selected Lenses Located At the Margins of Public Surveys (COOL-LAMPS) collaboration with lens redshifts ranging from 0.2 ⪅ z ⪅ 1.0 using the brightest-cluster-galaxy (BCG) redshift and an observable proxy for the Einstein radius. We constrain the Einstein-radius-enclosed luminosity and stellar mass by fitting parametric spectral energy distributions to aperture photometry from the Dark Energy Camera Legacy Survey (DECaLS) in the g -, r -, and z -band Dark Energy Camera filters. We find that the BCG redshift, enclosed total mass, and enclosed luminosity are strongly correlated and well described by a planar relationship in 3D space. We find that the enclosed total mass and stellar mass are correlated with a logarithmic slope of 0.50 0 − 0.031 + 0.029 , and the enclosed total mass and stellar-to-total mass fraction are correlated with a logarithmic slope of − 0.49 5 − 0.033 + 0.032 . In tandem with the small radii within which these slopes are constrained, this may suggest invariance in baryon conversion efficiency and feedback strength as a function of cluster-centric radii in galaxy clusters. Additionally, the correlations described here should have utility in ranking strong-lensing candidates in upcoming imaging surveys—such as Rubin/Legacy Survey of Space and Time—in which an algorithmic treatment of strong lenses will be needed due to the sheer volume of data these surveys will produce.

Mork, Simon D. (ORCID:0000000255739131)↗
DOE OSTI2025

Examining the Impact of Local Constraint Violations on Energy Computations in DFT

ABSTRACT This work examines the impact of locally imposed constraints in Density Functional Theory (DFT). Using a metric referred to as the extent of violation index (EVI), we quantify how well exchange‐correlation functionals adhere to local constraints. Applying EVIs to a diverse set of molecules for GGA functionals reveals constraint violations, particularly for semi‐empirical functionals. We leverage EVIs to explore potential connections between these violations and errors in chemical properties. While no correlation is observed for atomization energies, a significant statistical correlation emerges between EVIs and total energies. Similarly, the analysis of reaction energies suggests weak positive correlations for specific constraints. However, definitive conclusions about error cancellation mechanisms cannot be made at this time. These observations revealed by EVIs may be useful for consideration when designing future generations of semilocal functionals.

Khanna, Vaibhav [Department of Chemistry Universit↗
NASA NTRS1987

Radio continuum, far infrared and star formation

A very tight correlation was found between the radio emission and the far infrared emission from galaxies. This has been found for various samples of galaxies and is explained in terms of recent star formation. The tight correlation would imply that the total radio emission is a good tracer of star formation. The correlation between the radio power at 5 GHz and the far infrared luminosity is shown. The galaxies are of various morphological types and were selected from the various IRAS circulars, hence the sample is an infrared selected sample. The far infrared luminosities were corrected for the dust temperature. This is significant because it decreases the dispersion in the correlation.

Wielebinski, R.↗
NASA NTRS1988

C 4 fluxes from the sun as a star and the correlation with magnetic flux

A total of 144 C 4 wavelength 1548 SMM-UVSP spectroheliograms of solar plages were analyzed, some of which are series of exposures of the same region on the same day. Also analyzed were C 4 wavelength 1551 rasters of plages and C 4 1548 rasters of the quiet sun. The sample contains data on 17 different plages, observed on 50 different days. The center-to-limb variations of the active regions show that the optical thickness effects in the C 4 wavelength 1548 line can be neglected in the conversion from intensity to flux density. As expected for the nearly optically thin situation, the C 4 1548 line is twice as bright as the C 4 wavelength 1551 line. The average C 4 wavelength 1548 flux density for a quiet is 2700 erg/cm/s and, with surprisingly little scatter, 18,000 erg/cm/s for plages. The intensity histograms of rasters obtained at disk centers can be separated into characteristic plage and quiet-sun contributions with variable relative filling factors. The disk-averaged flux density in the C 4 doublet and the disk-averaged magnitude of the magnetic flux density are related. The relationship between the C 4 and magnetic flux densities for spatially resolved data is inferred to be almost the same, with only an additional factor of order unity in the constant of proportionality.

Schrijver, C. J.↗
NASA NTRS1988

C IV fluxes from the Sun as a star, and the correlation with magnetic flux

A total of 144 C IV wavelength 1548 Solar Maximum Mission (SMM)-UVSP spectroheliograms of solar plages were analyzed, some of which are series of exposures of the same region on the same day. Also analyzed were the C IV wavelength 1551 rasters of plages and C IV wavelength 1548 rasters of the quiet sun. The sample contained data on 17 different plages, observed on 50 different days. The center-to-limb variations of the active regions show that the optical thickness effects in the C IV wavelength 1548 line can be neglected in the conversion from intensity to flux density. As expected for the nearly optically thin situation, the C IV wavelength 1548 line is twice as bright as the C IV 1551 line. The average C IV wavelength 1548 flux density for a quiet region is 2700 ergs/cm/s and, with surprisingly little scatter, 18,000 erg/cm/s for plages. The intensity histograms of rasters obtained at disk center can be separated into characteristic plage and quiet sun contributions with variable relative filling factors. The relationship between the C IV and magnetic flux densities for spatially resolved data is inferred to be almost the same, with only an additional factor of order unity in the constant of proportionality.

Schrijver, C. J.↗