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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 1,171 records · Page 65
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Instrument development continues in Oak Ridge

Peer review panels composed of 80 external scientists recently visited Oak Ridge National Laboratory (ORNL) to review almost 700 proposals for experiments on 23 instruments at the Spallation Neutron Source (SNS) and High Flux Isotope Reactor (HFIR). These were proposed for the time period from January-June 2012. About 40% of the proposals were approved for beam time and 20% were placed on an alternate list if time becomes available. The Hybrid Spectrometer HYSPEC at SNS began its commissioning in September 2011. HYSPEC is otpimized for studying low energy dynamics in single-crystal samples using a broad variety of sample environments, and is equipped with a polarization analysis capability. It is expected to be available for users on a limited basis in the second half of 2012. The detector tank of CORELLI has been installed on beamline 9 at SNS. Now that the tank is in place, banks of neutron detectors and boron carbide shielding will be installed around the interior. CORELLI is optimized to probe complex disorder in crystalline materials through diffuse scattering from single-crystal samples. It will begin commissioning in 2014. CORELLI is one of four instruments being developed under the SING II (SNS Instruments Next Generation II) project. The others are the Macromolecular Neutron Diffractometer (MANDI), the Vibrational Spectrometer (VISION, scheduled to begin commissioning in 2012), and the Time of Flight Ultra Small Angle Neutron Scattering Instrument (TOF-USANS). The single crystal neutron diffractometer IMAGINE, was deliverd to HFIR in October 2011. Preliminary testing has been carried out. IMAGINE will provide atomic resolution information on chemical, organic, metallo-organic and protein single crystals that will enable their chemical, physical and biological structure and function to be understood. This instrument will benefit scientists with interests in pharmaceuticals, minerals and other inorganic crystals, small molecules, molecular organo-metallic crystals and metal-organic frameworks (MOFs) molecular crystal structures. The quasi-Laue geometry, combined with a large solid angle detector, will enable rapid data collection from crystals with volume < 1mm{sup 1} and unit cell < 100 {angstrom}. Construction and installation of the optical system is in progress. Commissioning is expected to start in April 2012.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

High-energy Neutron-induced Fission Cross Sections of Natural Lead and Bismuth-209

The CERN Neutron Time-Of-Flight (n-TOF) facility is well suited to measure small neutron-induced fission cross sections, as those of subactinides. The cross section ratios of {sup nat}Pb and {sup 209}Bi relative to {sup 235}U and {sup 238}U were measured using PPAC detectors. The fragment coincidence method allows to unambiguously identify the fission events. The present experiment provides the first results for neutron-induced fission up to 1 GeV for {sup nat}Pb and {sup 209}Bi. A good agreement with previous experimental data below 200 MeV is shown. The comparison with proton-induced fission indicates that the limiting regime where neutron-induced and proton-induced fission reach equal cross section is close to 1 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

La2MnV)6 Double Perovskite: a Structural Magnetic and X-ray Absorption Investigation

The synthesis, electron diffraction (ED), synchrotron X-ray and neutron structure, X-ray absorption spectroscopy (XAS) and magnetic property studies of La{sub 2}MnVO{sub 6} double perovskite are described. Analysis of the synchrotron powder X-ray diffraction data for La{sub 2}MnVO{sub 6} indicates a disordered arrangement of Mn and V at the B-site of the perovskite structure. Absence of super-lattice reflections in the ED patterns for La{sub 2}MnVO{sub 6} supports the disordered cation arrangement. Room temperature time-of-flight (TOF) neutron powder diffraction (NPD) data show no evidence of cation ordering, in corroboration with the ED and synchrotron studies (orthorhombic Pnma, a = 5.6097(3), b = 7.8837(5) and c = 5.5668(3) {angstrom}; 295 K, NPD). A comparison of XAS analyses of La{sub 2}TVO{sub 6} with T = Ni and Co shows T{sup 2+} formal oxidation state while the T = Mn material evidences a Mn{sup 3+} admixture into a dominantly Mn{sup 2+} ground state. V-K edge measurements manifest a mirror image behavior with a V{sup 4+} state for T = Ni and Co with a V{sup 3+} admixture arising in the T = Mn material. The magnetic susceptibility data for La{sub 2}MnVO{sub 6} show ferromagnetic correlations; the observed effective moment, {mu}{sub eff} (5.72 {micro}B) is much smaller than the calculated moment (6.16 {micro}B) based on the spin-only formula for Mn{sup 2+} (d{sup 5}, HS)/V{sup 4+} (d{sup 1}), supportive of the partly oxidized Mn and reduced V scenario (Mn{sup 3+}/V{sup 3+}).

36 MATERIALS SCIENCE↗
DOE OSTI2012

Wavelength-Shifting-Fiber Scintillation Detectors for Thermal Neutron Imaging at SNS

We have developed wavelength-Shifting-fiber Scintillator Detector (SSD) with 0.3 m2 area per module. Each module has 154 x 7 pixels and a 5 mm x 50 mm pixel size. Our goal is to design a large area neutron detector offering higher detection efficiency and higher count-rate capability for Time-Of-Flight (TOF) neutron diffraction in Spallation Neutron Source (SNS). A ZnS/6LiF scintillator combined with a novel fiber encoding scheme was used to record the neutron events. A channel read-out-card (CROC) based digital-signal processing electronics and position-determination algorithm was applied for neutron imaging. Neutron-gamma discrimination was carried out using pulse-shape discrimination (PSD). A sandwich flat-scintillator detector can have detection efficiency close to He-3 tubes (about 10 atm). A single layer flat-scintillator detector has count rate capability of 6,500 cps/cm2, which is acceptable for powder diffractometers at SNS.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

SYNTHESIS AND CHARACTERIZATION OF PYRIDINE END-FUNCTIONALIZED POLY (3-HEXYLTHIOPHENE)s: POTENTIAL LIGANDS FOR SQD/P3HT BHJs

Extensive research has been done to optimize donor-acceptor properties of bulk heterojunction organic photovoltaics (BHJ OPVs) leading to devices with relatively high power conversion efficiencies (>5%). Polymer-nanoparticle hybrid solar cells are one class of BHJ OPVs that incorporate nanoparticles (electron carrier) in a polymer matrix (hole carrier). Blending inorganic nanoparticles with an organic polymer matrix is challenging due to unfavorable interactions between the nanoparticle and polymer leading to aggregation and poor charge separation. One method to improve ordering of the BHJ is by use of ligands on the inorganic nanoparticles that facilitate homogenous dispersion within the polymer matrix. This paper will discuss the preparation of pyridine end-functionalized P3HTs by in situ quenching of the Grignard Metathesis Polymerization with functional Grignard reagents. The degree of functionality of the polymers is determined by MALDI-TOF MS. In addition, methods to optimize the functionality of the resulting polymer will also be discussed.

14 SOLAR ENERGY↗
DOE OSTI2012

Resonance neutron-capture cross sections of stable magnesium isotopes and their astrophysical implications

We have measured the neutron capture cross sections of the stable magnesium isotopes {sup 24,25,26}Mg in the energy range of interest to the s process using the neutron time-of-flight facility n{_}TOF at CERN. Capture events from a natural metal sample and from samples enriched in {sup 25}Mg and {sup 26}Mg were recorded using the total energy method based on C{sub 6}{sup 2}H{sub 6} detectors. Neutron resonance parameters were extracted by a simultaneous resonance shape analysis of the present capture data and existing transmission data on a natural isotopic sample. Maxwellian-averaged capture cross sections for the three isotopes were calculated up to thermal energies of 100 keV and their impact on s-process analyses was investigated. At 30 keV the new values of the stellar cross section for {sup 24}Mg, {sup 25}Mg, and {sup 26}Mg are 3.8 {+-} 0.2 mb, 4.1 {+-} 0.6 mb, and 0.14 {+-} 0.01 mb, respectively.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

A Multi-Anode Photomultiplier Tube Based Wavelength-Shifting-Fiber Detector for neutron diffraction

The wavelength-shifting (WLS) fiber scintillator neutron detectors were developed for two time-of-flight (TOF) neutron powder diffractometers (POWGEN, VULCAN) at Spallation Neutron Source (SNS). In a recent module (v3.0), however, there are 32 1-inch-diameter photomultiplier tubes (PMTs) which are bulky and expensive. We built a new detector module (v3.1) based on four multi-anode (MA) PMTs, and tested its performance including detection efficiency, count rate capability, spatial resolution, ghosting properties, and gamma-ray sensitivity. The v3.1 module was compared with two prior v3.0 modules, and 3He tube detectors.

Berry, Kevin D↗
DOE OSTI2011

SIMS and TEM Analysis of Niobium Bicrystals

The behaviour of interstitial impurities(C,O,N,H) on the Nb surface with respect to grain boundaries may affect cavity performance. Large grain Nb makes possible the selection of bicrystal samples with a well defined grain boundary. In this work, Dynamic SIMS was used to analyze two Nb bicrystal samples, one of them heat treated and the other non heat treated (control). H levels were found to be higher for the non heat treated sample and a difference in the H intensity and sputtering rate was also observed across the grain boundary for both the samples. TEM results showed that the bicrystal interface showed no discontinuity and the oxide layer was uniform across the grain boundary for both the samples. TOF-SIMS imaging was also performed to analyze the distribution of the impurities across the grain boundary in both the samples. C was observed to be segregated along the grain boundary for the control sample, while H and O showed a difference in signal intensity across the grain boundary. Crystal orientation appears to have an important role in the observed sputtering rate and impurity ion signal differences both across the grain boundary and between samples

36 MATERIALS SCIENCE↗
DOE OSTI2012

Method for improving the angular resolution of a neutron scatter camera

An instrument that will directly image the fast fission neutrons from a special nuclear material source wherein the neutron detection efficiency is increased has been described. Instead of the previous technique that uses a time-of-flight (TOF) between 2 widely spaced fixed planes of neutron detectors to measure scatter neutron kinetic energy, we now use the recoil proton energy deposited in the second of the 2 scatter planes which can now be repositioned either much closer together or further apart. However, by doubling the separation distance between the 2 planes from 20 cm to a distance of 40 cm we improved the angular resolution of the detector from about 12.degree. to about 10.degree.. A further doubling of the separation distance to 80 cm provided an addition improvement in angular resolution of the detector to about 6.degree. without adding additional detectors or ancillary electronics. The distance between planes also may be dynamically changed using a suitable common technique such as a gear- or motor-drive to toggle between the various positions. The angular resolution of this new configuration, therefore, is increased at the expanse of detection sensitivity. However, the diminished sensitivity may be acceptable for those applications where the detector is able to interrogate a particular site for an extended period.

47 OTHER INSTRUMENTATION↗
DOE OSTI2014

Reproducibility of High-Q SRF Cavities by High Temperature Heat Treatment

Recent work on high-temperature (> 600 °C) heat treatment of ingot Nb cavities in a customized vacuum furnace for several hours showed the possibility of achieving Q0-values of up to ~5×10 10 at 2.0 K, 1.5 GHz and accelerating gradients of ~20 MV/m. This contribution presents results on further studies of the heat treatment process to produce cavities with high Q0 values for continuous-wave accelerator application. Single-cell cavities of different Nb purity have been processed through few cycles of heat-treatments and chemical etching. Measurements of Q0 as a function of temperature at low RF field and of Q0 as a function of the RF field at or below 2.0 K have been made after each treatment. Measurements by TOF-SIMS of the impurities depth profiles were made on samples heat treated with the cavities.

Dhakal, Pashupati↗
DOE OSTI2014

Detection system for high-resolution gamma radiation spectroscopy with neutron time-of-flight filtering

A .gamma.-radiation detection system that includes at least one semiconductor detector such as HPGe-Detector, a position-sensitive .alpha.-Detector, a TOF Controller, and a Digitizer/Integrator. The Digitizer/Integrator starts to process the energy signals of a .gamma.-radiation sent from the HPGe-Detector instantly when the HPGe-Detector detects the .gamma.-radiation. Subsequently, it is determined whether a coincidence exists between the .alpha.-particles and .gamma.-radiation signal, based on a determination of the time-of-flight of neutrons obtained from the .alpha.-Detector and the HPGe-Detector. If it is determined that the time-of-flight falls within a predetermined coincidence window, the Digitizer/Integrator is allowed to continue and complete the energy signal processing. If, however, there is no coincidence, the Digitizer/Integrator is instructed to be clear and reset its operation instantly.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2010

GRD Import

Imports RAW data (*.GRD) files created by Ion-TOF’s SurfaceLab version 6.1 or later into Matlab and saves the resulting variables to a file.

Ohlhausen, James A.↗
DOE OSTI2018

Tomographic Reconstruction of the Neutron Time-Energy Spectrum from a Dense Plasma Focus

As a pulsed neutron source, a Dense Plasma Focus (DPF) has a wide range of applications including active interrogation of special nuclear materials. In order to measure the material properties of interest with high accuracy and low uncertainties, the properties of the neutron pulse generated by the DPF must be well characterized including the peak neutron energy and the neutron energy density. These quantities can be inferred by measuring neutron counts on a collection of radiation detectors at difference distances using time-of-flight (TOF) principles.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

The NOvA Test Beam Experiment

aThe motivation for the NOvA test beam project is to understand a number of limiting factors that impinges the NOvA's analyses. These factors include the detector’s hadronic and electromagnetic shower response, light yield and optical transportation, as well as discrepancies between data and MC modeling of the detector. In addition, the test beam setup will collect data to build a large libraries of particle interactions at well-known energies, which would later become a useful input in the development of better data driven PID algorithms for NOvA's analyses. The main component of the experiment - two 2$\times$2$\times$32 blocks, filled with NOvA liquid scintillator - is placed along the MC7 beamline to study the interaction with beam particles. The tertiary beam composes primarily of protons and pions as well as a discernible contribution from electrons, muons and kaons, all within a momentum range from 0.3 to 2 GeV$/c$. The PID and kinematics of beam particles will be determined by the auxiliary detectors including four MWPCs, two TOFs and a CO$_2$ gas Cherenkov counter. In this poster, recent status on beamline instrumentation, data acquisition, simulation, momentum reconstruction and PID will be presented. Also, implications for the neutrino oscillation measurements will be discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Three-Dimensional Resistivity vs. Depth Profiling for Advanced Characterization of the Lithium-Ion Battery Solid Electrolyte Interphase

In this work, we investigate the evolution of SEI formed from a standard electrolyte (1.2 M LiPF6 in EC:EMC (3:7 wt%)) through various points in cycling on several model Si surfaces. We also examine the solubility of SEI by resting the anode in the cell at varied temperatures then characterizing the residual SEI. Evolution of the SEI surface is also analyzed with atomic force microscopy (AFM) measurements. AFM and SSRM-derived results are presented in combination with chemical characterization, including time-of-flight secondary ion mass spectrometry (TOF-SIMS).

25 ENERGY STORAGE↗
DOE OSTI2019

Plotting XPS Narrow Scans (and other Data) with MATLAB’s Powerful Plotting Capabilities, 2. An Introduction to Handle Graphics

The graphical representation of numerical data plays a vital role in chemistry, materials science, and every other scientific field. No matter how good your results are, poorly represented data can ultimately make your work confusing. Indeed, with an increase in the amount of data that is being gathered, e.g., by the Materials Genome Initiative, or in X-ray photoelectron spectroscopy (XPS) or time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiles, the importance of effectively representing data has increased. Good figures also matter because many researchers will not look at more than the title, abstract, and perhaps a few key figures from a paper.

42 ENGINEERING↗
DOE OSTI2020

Apparatus and method for determining state of change (SOC) and state of health (SOH) of electrical cells

Systems and methods for prediction of state of charge (SOH), state of health (SOC) and other characteristics of batteries using acoustic signals, includes determining acoustic data at two or more states of charge and determining a reduced acoustic data set representative of the acoustic data at the two or more states of charge. The reduced acoustic data set includes time of flight (TOF) shift, total signal amplitude, or other data points related to the states of charge. Machine learning models use at least the reduced acoustic dataset in conjunction with non-acoustic data such as voltage and temperature for predicting the characteristics of any other independent battery.

25 ENERGY STORAGE↗
DOE OSTI2021

Feedstock and Catalyst Impact on Bio-Oil Production and FCC Co-Processing to Fuels

NREL’s thermochemical biomass conversion research is focused on ex-situ upgrading of biomass fast-pyrolysis (FP) vapors as an efficient and economical route to completely biogenic pyrolysis-based fuel precursors, potential fuels, and value-added chemicals depending on catalyst choice and process conditions. In this approach, biomass vapors are generated via fast pyrolysis with destabilizing vapor components (char, inorganics, tar aerosols) removed by hot gas filtration to produce conditioned vapors more responsive to catalytic upgrading. A Davison Circulating Riser (DCR), a petroleum industry standard for fluidized catalytic cracking (FCC) catalyst evaluation, was coupled with a custom pyrolyzer system designed to produce consistent composition pyrolysis vapors as feed to the DCR. The coupled system is shown below (Figure 1). Pyrolysis vapors, derived from pure hardwood and softwood, were upgraded using commercially available and laboratory modified zeolite-based catalysts. Upgraded oils were analyzed via 31P and 13C NMR spectroscopy, GCxGC-TOF/MS, carbonyl and ultimate analysis (CHNO), and micro distillation to assess both oil chemistry and distillation behavior as they relate to catalyst and feedstock type for producing fungible hydrocarbon product liquids. Measured process parameters identified from technoeconomic process analysis included achieving oil oxygenate contents of 20% or less, carbon-conversion efficiencies of 30% or more, and catalyst coking rates of 10% or less. A proprietary modified zeolite catalyst from Johnson Matthey produced oils that met these requirements. Using the DCR equipped with a proprietary nozzle system, a second approach focused on reducing the carbon intensity of petroleum-derived hydrocarbon fuels by FCC co-processing these CFP oils with petroleum vacuum gas oil (VGO) to produce biogenic carbon containing fuels. The vapor-phase upgrading results demonstrated for the first time the feasibility of producing refinery-compatible hydrocarbon fuel intermediates entirely from biomass-derived fast-pyrolysis vapors using an industry-accepted DCR system for catalytic upgrading. The co-processing results demonstrated the feasibility of using CFP oils with VGO feeds in FCC refinery operations to produce biogenic carbon containing fuels.

bio-oil↗