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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Spectroscopic enhancement in nanoparticles embedded glasses

This presentation provides an overview of the recent progress in the enhancement of the spectroscopic characteristics of the glass embedded with nanoparticles (NPs). Some of our research activities with few significantly new results are highlighted and facilely analyzed. The science and technology dealing with the manipulation of the physical properties of rare earth doped inorganic glasses by embedding metallic NPs or nanoclusters produce the so-called 'nanoglass'. Meanwhile, the spectroscopic enhancement relates the intensity of the luminescence measured at certain transition. The enhancement which expectedly due to the 'plasmonics wave' (referring to the coherent coupling of photons to free electron oscillations called plasmon) occurs at the interface between a conductor and a dielectric. Plasmonics being an emerging concept in advanced optical material of nanophotonics has given this material the ability to exploit the optical response at nanoscale and opened up a new avenue in metal-based glass optics. There is a vast array of plasmonic NPs concepts yet to be explored, with applications spanning solar cells, (bio) sensing, communications, lasers, solid-state lighting, waveguides, imaging, optical data transfer, display and even bio-medicine. Localized surface plasmon resonance (LSPR) can enhance the optical response of nanoglass by orders of magnitude as observed. The luminescence enhancement and surface enhanced Raman scattering (SERS) are new paradigm of research. The enhancement of luminescence due to the influence of metallic NPs is the recurring theme of this paper.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Practical aspects of diffractive imaging using an atomic-scale coherent electron probe

Four-dimensional scanning transmission electron microscopy (4D-STEM) is a technique where a full two-dimensional convergent beam electron diffraction (CBED) pattern is acquired at every STEM pixel scanned. Capturing the full diffraction pattern provides a rich dataset that potentially contains more information about the specimen than is contained in conventional imaging modes using conventional integrating detectors. In this work, using 4D datasets in STEM from two specimens, monolayer MoS 2 and bulk SrTiO 3 , we demonstrate multiple STEM imaging modes on a quantitative absolute intensity scale, including phase reconstruction of the transmission function via differential phase contrast imaging. Finally, practical issues about sampling (i.e. number of detector pixels), signal-to-noise enhancement and data reduction of large 4D-STEM datasets are emphasized.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Luminescence properties of ZnMoO{sub 4}:Eu{sup 3+}:Y{sup 3+} materials synthesized by solution combustion synthesis method

The Zn{sub (1-x-y)}MoO{sub 4}:Eu{sup 3+}{sub (x)}: Y{sup 3+}{sub (y)} (x = 1 mol% and y = 1 or 2 mol%) compounds were prepared by combustion synthesis method. The crystal structure of the samples was identified by X-ray diffraction (XRD). The photoluminescence properties were investigated and it is observed that the co-doping of Y{sup 3+} enhances the luminescence emission intensity of ZnMoO{sub 4}:Eu{sup 3+} material. The Y{sup 3+} acts as a sensitizer in the ZnMoO{sub 4}:Eu{sup 3+} lattice. The particle size is calculated from XRD data by using Scherer Equation. The particles has been found in the range of 30-40 nm.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Neutron activation of natural materials in a PWR spectrum: feedback on {sup 116m}In relative γ emission intensities and half-life

During the MAESTRO program, carried out between 2011 and 2014 in MINERVE zero power reactor, common Gen-II and Gen-III light water reactor materials were irradiated. For some of these materials, the decay of their activation products was also measured by γ spectrometry. Initially devoted to the measurement of the integral capture cross section by activation and reactivity-oscillation method, these results can also provide useful information on decay data of various radionuclides. This approach of this experiment led to a common roadmap shared by the Experimental Physics Section and the Henri Becquerel National Laboratory to improve decay data in nuclear data libraries. Results discussed in this paper concern the relative emission intensities of the main γ rays of {sup 116m}In. Six irradiations of samples with various physical forms of {sup nat}In were carried out. Measurements were analyzed using decay data from several evaluations and it is shown that γ ray activities are not consistent. Analyses were carried out to provide new relative γ emission intensities from these measurements. The {sup 116m}In half-life has also been measured and shows a good agreement with existing values. Finally, an overview of the foreseen results on additional decay data from the MAESTRO program is given. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2016

Aethalometer™ Instrument Handbook

The Aethalometer is an instrument that provides a real-time readout of the concentration of “Black” or “Elemental” carbon aerosol particles (BC or E) in an air stream (see Figure 1 and Figure 2). It is a self-contained instrument that measures the rate of change of optical transmission through a spot on a filter where aerosol is being continuously collected and uses the information to calculate the concentration of optically absorbing material in the sampled air stream. The instrument measures the transmitted light intensities through the “sensing” portion of the filter, on which the aerosol spot is being collected, and a “reference” portion of the filter as a check on the stability of the optical source. A mass flowmeter monitors the sample air flow rate. The data from these three measurements is used to determine the mean BC content of the air stream.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

High throughput screening of ultra-thin electrocaloric materials enabled by additive manufacturing

Current HVAC systems can constitute as much as half of a building’s total energy consumption, depending on its use. More specifically cooling, particularly in hotter climates or for energy intensive applications, like data centers, can comprise between 10-30% of the total energy use. These cooling systems are largely comprised of compressor-based direct expansion systems and chilled water systems that use refrigerants or water, respectively, to reject heat. . Electrocaloric (EC) cycles present an eco-friendly alternative to these conventional processes.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Status and Plan of DUNE at Fermilab

The discovery and the solid confirmation of neutrino flavor oscillation have been made throughout late 1990 to 2000s. Such oscillation is the clear proof of non-zero neutrino mass since this is caused by the fact that the neutrino mass eigenstates differ from that of the flavor. The neutrinos in the Standard Model, however, are massless leptons, and thus the neutrino flavor oscillation necessitates either the Standard Model to be significantly modified or a new theoretical paradigm to describe the universe better. In order to provide experimental information, it is essential for the properties of the neutrino oscillation be well understood through precision measurements of oscillation parameters, including the mixing angles, determination of the mass hierarchy between the three mass eigenstates and determination of the CP phase (Delta_CP) between neutrino and anti-neutrino oscillations. Among the several next generation neutrino experiments, this presentation covers the Deep Underground Neutrino Experiment (DUNE) which, with the high intensity neutrino beam facility, will help accomplish these goals. In this report, I will discuss the current status and plan of the DUNE experiment, including the results of the detector performance studies from the large scale prototype detectors operating at CERN and the timeline for construction and data taking of the experiment, as well as its physics prospects.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

Impact of data assimilation on Eulerian versus Lagrangian estimates of upper ocean transport

Using four-dimensional variational analysis, we produce an estimate of the state of a coastalregion in Northern Norway during the late winter and spring in 1984. We use satellite sea surface tempera-ture and in situ observations from a series of intensive field campaigns, and obtain a more realistic distribu-tion of water masses both in the horizontal and the vertical than a pure downscaling approach can achieve.Although the distribution of Eulerian surface current speeds are similar, we find that they are more variableand less dependent on model bathymetry in our reanalysis compared to a hindcast produced using thesame modeling system. Furthermore, Lagrangian drift currents on the other hand are significantly changed, with overallhigher kinetic energy levels in the reanalysis than in the hindcast, particularly in the superinertial frequencyband.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Optimal binning of correlated measurements

Experimental measurements are commonly represented on a discrete grid, requiring a balance between granularity and statistical noise. Two strategies have traditionally been used to improve such representations: selecting an appropriate bin width to control discretization error and applying kernel-based smoothing to suppress fluctuations. Despite their shared goal, these approaches have largely developed independently, without a unified statistical description of how discretization and correlation jointly determine measurement precision. Here, we extend the discussion of optimal interval averaging to a correlation-aware setting by Gaussian process regression, which explicitly accounts for correlations among neighboring bins. Starting from first principles, we derive the mean-squared error of discretized measurements and obtain closed-form asymptotic expressions for the optimal bin width and correlation length. When recast in reduced variables, the theory reveals distinct universal scaling laws governing the error in the correlation-free and correlation-controlled regimes. Characterized by intrinsically smooth intensity profiles and counting-based statistics, neutron scattering measurements are well suited for demonstrating the enhanced error contraction enabled by inter-bin correlations. We show that such improvement is achievable over the experimentally accessible Q-range and across multiple instruments and material systems. These results show that explicitly accounting for correlations systematically reshapes the limits of precision in discretized, noise-limited measurements. More broadly, the framework provides a transferable statistical foundation for optimizing data representation, inference, and experimental design across the physical and data sciences.

Tung, Chi-Huan [ORNL] (ORCID:0000000221972074)↗
DOE OSTI2024

Report on branching ratios for 111 Ag

Our understanding on the distribution of fragment masses following fission, or fission yields is largely impacted by the quality of nuclear data. One of the most straightforward and reliable ways to determine the number of fissions that occurred in a chain reaction is done via detection of the characteristic γ-rays emitted during the β decay of the fission product. These γ rays are emitted in only a fraction of the decays, and this fraction (the γ-ray intensities) must be known accurately to determine the total number of fissions. Many long-lived fission products, such as 111 Ag, play an important role in science-based stockpile stewardship and nuclear forensics. The γ-ray intensities from the decay of 111 Ag are known to only 5%, leading to a 5% uncertainty in fission-chain yield. This work aims to improve the precision of these γ-ray intensities for the most intense emissions following the decay of 111 Ag, as seen in Figure 1.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Assessing Internet energy intensity: A review of methods and results

Assessing the average energy intensity of Internet transmissions is a complex task that has been a controversial subject of discussion. Estimates published over the last decade diverge by up to four orders of magnitude — from 0.0064 kilowatt-hours per gigabyte (kWh/GB) to 136 kWh/GB. This article presents a review of the methodological approaches used so far in such assessments: i) top–down analyses based on estimates of the overall Internet energy consumption and the overall Internet traffic, whereby average energy intensity is calculated by dividing energy by traffic for a given period of time, ii) model-based approaches that model all components needed to sustain an amount of Internet traffic, and iii) bottom–up approaches based on case studies and generalization of the results. Our analysis of the existing studies shows that the large spread of results is mainly caused by two factors: a) the year of reference of the analysis, which has significant influence due to efficiency gains in electronic equipment, and b) whether end devices such as personal computers or servers are included within the system boundary or not. For an overall assessment of the energy needed to perform a specific task involving the Internet, it is necessary to account for the types of end devices needed for the task, while the energy needed for data transmission can be added based on a generic estimate of Internet energy intensity for a given year. Separating the Internet as a data transmission system from the end devices leads to more accurate models and to results that are more informative for decision makers, because end devices and the networking equipment of the Internet usually belong to different spheres of control. -- Highlights: • Assessments of the energy intensity of the Internet differ by a factor of 20,000. • We review top–down, model-based, and bottom–up estimates from literature. • Main divergence factors are the year studied and the inclusion of end devices. • We argue against extending the Internet system boundary beyond data transmission. • Decision-makers need data that differentiates between end devices and transmission.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2015

Determination of crystallographic intensities from sparse data

X-ray serial microcrystallography involves the collection and merging of frames of diffraction data from randomly oriented protein microcrystals. The number of diffracted X-rays in each frame is limited by radiation damage, and this number decreases with crystal size. The data in the frame are said to be sparse if too few X-rays are collected to determine the orientation of the microcrystal. It is commonly assumed that sparse crystal diffraction frames cannot be merged, thereby setting a lower limit to the size of microcrystals that may be merged with a given source fluence. The EMC algorithm [Loh & Elser (2009), Phys. Rev. E , 80 , 026705] has previously been applied to reconstruct structures from sparse noncrystalline data of objects with unknown orientations [Philipp et al. (2012), Opt. Express , 20 , 13129–13137; Ayyer et al. (2014), Opt. Express , 22 , 2403–2413]. Here, it is shown that sparse data which cannot be oriented on a per-frame basis can be used effectively as crystallographic data. As a proof-of-principle, reconstruction of the three-dimensional diffraction intensity using sparse data frames from a 1.35 kDa molecule crystal is demonstrated. The results suggest that serial microcrystallography is, in principle, not limited by the fluence of the X-ray source, and collection of complete data sets should be feasible at, for instance, storage-ring X-ray sources.

Chemistry↗
DOE OSTI2018

Radiation Crosslinking of Modifying Super Absorbent (Polyacrylamide/Gelatin) Hydrogel as Fertilizers Carrier and Soil Conditioner

A novel approach is developed for preparing a highly porous super absorbent hydrogel (SAH). Synthetic and natural hydrogel based acrylamide (Am) and gelatin (G) were polymerized and crosslinked by gamma radiation. Three hydrogels compositions have been prepared in weight ratio 1:2, 1.5:1.5 and 2:1 (wt:wt) for 30% PAAM/G and exposed to gamma radiation at dose of 30 kGy. The effect of chemical modifications on increasing the swelling power of polyacrylamide gelatin (PAAM/G) has been evaluated. The alkaline hydrolysis of PAAM/G hydrogel with concentrated NaOH converts amid groups CONH{sub 2} to carboxylic groups COONa. The modified hydrogels will take the codes PAAM-COOH/G, PAAM-COONa/G and PAAM-COOK/G that dramatically increased the degree of swelling from 220 to 720 (g/g). Furthermore, studies on the slow release ability of three kinds of fertilizer (K, P and urea) loaded on modified PAAM-COOH/G and evaluated the ability of SAH hydrogels to absorb and then gradually release water and fertilizer. A mathematical model for fertilizer release from PAAM-COOK/G was applied to calculate the diffusion coefficient D. The main aim of this article is performed the effect of soil amendment with PAAM-COOK/G on eliminating water stress was tested for bean plant (Vicia faba) irrigation cycles in drought-prone environments. The growth of bean plant was monitored by measuring the highest and size of leaves and bean seed. The effect of water stress was monitored also, by measuring the intensity of chlorophyll for both SAH and control soil. The results indicated that the chemical modification of (PAAM/G) into (PAAM-COOK/G) could greatly improve water absorbency. The experimental data indicated that the SAH has a positive effect to use as fertilizers carrier and soil conditioner.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Impact of obesity on 7,12-dimethylbenz[a]anthracene-induced altered ovarian connexin gap junction proteins in female mice

The ovarian gap junction proteins alpha 4 (GJA4 or connexin 37; CX37), alpha 1 (GJA1 or connexin 43; CX43) and gamma 1 (GJC1 or connexin 45; CX45) are involved in cell communication and folliculogenesis. 7,12-dimethylbenz[a]anthracene (DMBA) alters Cx37 and Cx43 expression in cultured neonatal rat ovaries. Additionally, obesity has an additive effect on DMBA-induced ovarian cell death and follicle depletion, thus, we investigated in vivo impacts of obesity and DMBA on CX protein levels. Ovaries were collected from lean and obese mice aged 6, 12, 18, or 24 wks. A subset of 18 wk old mice (lean and obese) were dosed with sesame oil or DMBA (1 mg/kg; ip) for 14 days and ovaries collected 3 days thereafter. Cx43 and Cx45 mRNA and protein levels decreased (P < 0.05) after 18 wks while Cx37 mRNA and protein levels decreased (P < 0.05) after 24 wks in obese ovaries. Cx37 mRNA and antral follicle protein staining intensity were reduced (P < 0.05) by obesity while total CX37 protein was reduced (P < 0.05) in DMBA exposed obese ovaries. Cx43 mRNA and total protein levels were decreased (P < 0.05) by DMBA in both lean and obese ovaries while basal protein staining intensity was reduced (P < 0.05) in obese controls. Cx45 mRNA, total protein and protein staining intensity level were decreased (P < 0.05) by obesity. These data support that obesity temporally alters gap junction protein expression and that DMBA-induced ovotoxicity may involve reduced gap junction protein function. - Highlights: • Ovarian gap junction proteins are affected by ovarian aging and obesity. • DMBA exposure negatively impacts gap junction proteins. • Altered gap junction proteins may contribute to infertility.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Efficient Probabilistic Prediction and Uncertainty Quantification of Tropical Cyclone–Driven Storm Tides and Inundation

Abstract This study proposes and assesses a methodology to obtain high-quality probabilistic predictions and uncertainty information of near-landfall tropical cyclone–driven (TC-driven) storm tide and inundation with limited time and resources. Forecasts of TC track, intensity, and size are perturbed according to quasi-random Korobov sequences of historical forecast errors with assumed Gaussian and uniform statistical distributions. These perturbations are run in an ensemble of hydrodynamic storm tide model simulations. The resulting set of maximum water surface elevations are dimensionality reduced using Karhunen–Loève expansions and then used as a training set to develop a polynomial chaos (PC) surrogate model from which global sensitivities and probabilistic predictions can be extracted. The maximum water surface elevation is extrapolated over dry points incorporating energy head loss with distance to properly train the surrogate for predicting inundation. We find that the surrogate constructed with third-order PCs using elastic net penalized regression with leave-one-out cross validation provides the most robust fit across training and test sets. Probabilistic predictions of maximum water surface elevation and inundation area by the surrogate model at 48-h lead time for three past U.S. landfalling hurricanes (Irma in 2017, Florence in 2018, and Laura in 2020) are found to be reliable when compared to best track hindcast simulation results, even when trained with as few as 19 samples. The maximum water surface elevation is most sensitive to perpendicular track-offset errors for all three storms. Laura is also highly sensitive to storm size and has the least reliable prediction. Significance Statement The purpose of this study is to develop and evaluate a methodology that can be used to provide high-quality probabilistic predictions of hurricane-induced storm tide and inundation with limited time and resources. This is important for emergency management purposes during or after the landfall of hurricanes. Our results show that sampling forecast errors using quasi-random sequences combined with machine learning techniques that fit polynomial functions to the data are well suited to this task. The polynomial functions also have the benefit of producing exact sensitivity indices of storm tide and inundation to the forecasted hurricane properties such as path, intensity, and size, which can be used for uncertainty estimation. The code implementing the presented methodology is publicly available on GitHub.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

THE LOW-FREQUENCY CHARACTERISTICS OF PSR J0437–4715 OBSERVED WITH THE MURCHISON WIDE-FIELD ARRAY

We report on the detection of the millisecond pulsar PSR J0437–4715 with the Murchison Wide-field Array (MWA) at a frequency of 192 MHz. Our observations show rapid modulations of pulse intensity in time and frequency that arise from diffractive scintillation effects in the interstellar medium (ISM), as well as prominent drifts of intensity maxima in the time-frequency plane that arise from refractive effects. Our analysis suggests that the scattering screen is located at a distance of ∼80-120 pc from the Sun, in disagreement with a recent claim that the screen is closer (∼10 pc). Comparisons with higher frequency data from Parkes reveal a dramatic evolution of the pulse profile with frequency, with the outer conal emission becoming comparable in strength to that from the core and inner conal regions. As well as demonstrating the high time resolution science capabilities currently possible with the MWA, our observations underscore the potential to conduct low-frequency investigations of timing-array millisecond pulsars, which may lead to increased sensitivity in the detection of nanoHertz gravitational waves via the accurate characterization of ISM effects.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

Serial snapshot crystallography for materials science with SwissFEL

New opportunities for studying (sub)microcrystalline materials with small unit cells, both organic and inorganic, will open up when the X-ray free electron laser (XFEL) presently being constructed in Switzerland (SwissFEL) comes online in 2017. Our synchrotron-based experiments mimicking the 4%-energy-bandpass mode of the SwissFEL beam show that it will be possible to record a diffraction pattern of up to 10 randomly oriented crystals in a single snapshot, to index the resulting reflections, and to extract their intensities reliably. The crystals are destroyed with each XFEL pulse, but by combining snapshots from several sets of crystals, a complete set of data can be assembled, and crystal structures of materials that are difficult to analyze otherwise will become accessible. Even with a single shot, at least a partial analysis of the crystal structure will be possible, and with 10–50 femtosecond pulses, this offers tantalizing possibilities for time-resolved studies.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Search for lightly ionizing particles in superCDMS and simulation of neutron backgrounds

The Super Cryogenic Dark Matter Search (SuperCDMS) is a direct-detection dark matter search experiment that primarily aims to search for Weakly Interacting Massive Particles (WIMPs) using state-of-the-art solid-state detection technology. During its operation at the Soudan underground laboratory, germanium detectors were operated with high bias voltage mode known as the CDMS low ionization threshold experiment (CDMSlite) to achieve below-keV thresholds. CDMSlite, for being able to measure small energy depositions in detectors, also provides sensitivity to Lightly Ionizing Particles (LIPs) with very small fractional charges. This thesis will discuss an analysis to search LIPs with the data acquired in CDMSlite mode. An important component for LIPs search is the expected energy-deposition distributions for LIPs falling on the CDMSlite detector. In this thesis, a simulation framework to calculate the energy-deposition distributions is developed. This thesis presents first direct-detection limits on the intensity of cosmogenic LIPs with electric charges smaller than e/(3 × 105) as well as the strongest limits for charges ≤ e/160, with a minimum intensity of 1.36 × 10-7 cm-2s-1sr-1 at charge e/160.In any rare-event search experiment, understanding background is crucial. Neutrons capable of mimicking dark matter signals are a major background for any dark matter search experiment. A simulationmore » study to estimate the neutron background for an India based dark matter search experiment at Jaduguda Underground Science Laboratory (JUSL) is performed. The experiment at JUSL will be the first phase of a proposed Dark matter search at India-based Neutrino Observatory (DINO). It will be a direct detection experiment with primary aims to search for WIMPs as dark matter candidates. In this thesis, we discuss the methodology of estimating neutron flux at JUSL and report the results. The total neutron flux reaching the laboratory above 1 MeV energy threshold is found to be 5.76(±0.69) × 10-6 cm-2s-1. The impact of neutron background on the sensitivity of the experiment to detect dark matter at JUSL is also discussed. The thesis is organized as follows. Chapter 1 provides a brief introduction to the Lightly Ionizing Particle (LIPs). The analysis to search LIPs in SuperCDMS is briefly outlined in the chapter. This chapter also discusses the importance of neutron background estimates in a dark matter search experiment, more specifically, in the context of a proposed India-based dark matter search experiment at Jaduguda Underground Science Laboratory. In Chapter 2, the SuperCDMS experiment is introduced. In Chapter 3, the framework developed to perform simulations for Lightly Ionizing Particles is presented. In Chapter 4, the LIPs search analysis with the CDMSlite data and the results are discussed. In Chapter 5, the simulation of neutron background and the feasibility of dark-matter search at JUSL is discussed. Finally, conclusions from all the results discussed in this thesis are presented in Chapter 6.« less

Banik, Samir↗