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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Temperature and Pressure Instrumentation for LYNM PE1 Chemical Explosive Testing

Underground chemical explosive testing has been conducted at the Nevada National Security Site under the Physics Experiment 1 (PE1) to validate explosive computer modeling and, ultimately, improve the accuracy of subsurface explosive detection. This SAND Report describes the dynamic temperature and pressure measurements within the chamber induced by the chemical explosive for the first of three experiments, PE1-A. The report details the instrumentation used for the experiment, the emplacement of the hardware, and the measured results. Dynamic temperature measurements were accomplished with the use of optical spectrometers and dynamic pressure was measured with a series of high-rated pressure transducers. This report includes details of the design and results of four cavity sensor systems used to measure early-time temperature, early-time pressure, late-time temperature, and late time pressure. The outcomes of PE1-A were used to inform the design of the remaining PE1 series experiments, PE1-B and PE1-DL.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2020

A multi-wavelength streaked optical pyrometer for dynamic shock compression measurements above 2500 K

This work presents a concept and implementation of a calibrated streaked spectral pyrometer (SSP) temperature diagnostic used in dynamically driven shock experiments on a two-stage gas gun. This system relies upon measuring the total system response using a tunable monochromator, a NIST-traceable calibrated power meter, and a SSP. The diagnostic performance is validated against previously measured temperatures of shock driven z-cut quartz at 99 GPa and 93 GPa. The results are found to agree with the literature to within 5% and are discussed in this manuscript. The experimental setup utilizes measurements from multiple SSP systems per sample, providing several independent measurements and substantially increasing confidence in the extrapolated shock driven sample temperature.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2026

Measuring labor productivity dynamics in U.S. industrial and electric power sectors: a case study (2014–2023)

This study proposes a subsystem methodology for measuring labor productivity in the U.S. industrial and electric power sectors by leveraging public data available between 2014 and 2023. Building on Pasinetti’s framework and subsequent developments, the approach employs Vertically Integrated Sectors (VIS) to account for both direct and indirect productivity effects. The novelty of this work is twofold. First, it enables the estimation of productivity trends over time, providing a robust foundation for empirical analysis. Second, it applies the methodology to a case study of the electric generation sector, highlighting its practical relevance. Using data from the Bureau of Economic Analysis, the Bureau of Labor Statistics, and the Impact Analysis for Planning (IMPLAN) tool, the study reveals significant discrepancies between conventional productivity measures and those derived from the VIS approach. Furthermore, the proposed method aligns with the principles of Integrated Energy Systems by capturing the interrelations among generation, distribution, storage, and consumption. This alignment underscores its utility and applications for energy-related policy and planning. Overall, the findings contribute to more precise labor productivity assessments, supporting informed decision-making and future research. Additionally, the method highlights the importance of considering the whole supply chain, providing interrelated metrics for labor productivity which includes both, direct and indirect effects on the final labor productivity metric. By incorporating intersectoral dependencies, this method offers a more comprehensive and accurate measure of labor productivity compared to traditional metrics.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Measurement of the dynamic charge susceptibility near the charge density wave transition in ErTe 3

A charge density wave (CDW) is a phase of matter characterized by a periodic modulation of valence electron density coupled with lattice distortion. Its formation is closely tied to the dynamical charge susceptibility, χ(q, ω) , which reflects the collective electron dynamics of the material. Despite decades of study, χ(q, ω) near a CDW transition has never been measured at nonzero momentum, q, with meV energy resolution. Here, we investigate the canonical CDW transition in ErTe 3 using momentum-resolved electron energy loss spectroscopy, a technique uniquely sensitive to valence band charge excitations. Unlike phonons, which soften via the Kohn anomaly, we find the electronic excitations exhibit purely relaxational dynamics well described by a diffusive model, with the diffusivity peaking just below the critical temperature, T C1 . Additionally, we report for the first time a divergence in the real part of χ(q, ω) in the static limit (ω → 0), a long-predicted hallmark of CDWs. Unexpectedly, this divergence occurs as T → 0, with only a weak thermodynamic signature at T = T C1 . Our study necessitates a reexamination of the traditional description of CDW formation in quantum materials.

M-EELS↗
DOE OSTI2024

The Dynamic Assimilation Technique measures photosynthetic CO2 response curves with similar fidelity as steady-state approaches in half the time

The net CO2 assimilation (A) response to intercellular CO2 concentration (Ci) is a fundamental measurement in photosynthesis and plant physiology research. The conventional A/Ci protocols rely on steady-state measurements and take 15-40 minute per measurement, limiting data resolution or biological replication. Additionally, there are several CO2 protocols employed across the literature, without clear consensus as to the optimal protocol or systematic biases in their estimations. We compared the non-steady state Dynamic Assimilation Technique (DAT) protocol and the three most used CO2 protocols in steady-state measurements, and tested whether different CO2 protocols lead to systematic differences in estimations of the biochemical limitations to photosynthesis.

A/Ci response↗
DOE OSTI2024

The Dynamic Assimilation Technique measures photosynthetic CO 2 response curves with similar fidelity to steady-state approaches in half the time

The net CO 2 assimilation (A) response to intercellular CO 2 concentration (C i ) is a fundamental measurement in photosynthesis and plant physiology research. The conventional A/C i protocols rely on steady-state measurements and take 15–40 min per measurement, limiting data resolution or biological replication. Additionally, there are several CO 2 protocols employed across the literature, without clear consensus as to the optimal protocol or systematic biases in their estimations. We compared the non-steady-state Dynamic Assimilation Technique (DAT) protocol and the three most used CO 2 protocols in steady-state measurements, and tested whether different CO 2 protocols lead to systematic differences in estimations of the biochemical limitations to photosynthesis. The DAT protocol reduced the measurement time by almost half without compromising estimation accuracy or precision. The monotonic protocol was the fastest steady-state method. Estimations of biochemical limitations to photosynthesis were very consistent across all CO 2 protocols, with slight differences in Rubisco carboxylation limitation. The A/C i curves were not affected by the direction of the change of CO 2 concentration but rather the time spent under triose phosphate utilization (TPU)-limited conditions. Our results suggest that the maximum rate of Rubisco carboxylation (V cmax ), linear electron flow for NADPH supply (J), and TPU measured using different protocols within the literature are comparable, or at least not systematically different based on the measurement protocol used.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Self-Assembly of Silica Nanoparticles at Water–Hydrocarbon Interfaces: Insights from In Operando Small-Angle X-ray Scattering Measurements and Molecular Dynamics Simulations

To achieve tunable controls on the interactions of siliceous materials in subsurface environments bearing water and hydrocarbons, it is essential to determine the influence of hydrocarbon–water interfaces on the self-assembly of the silica particles. The hydrophilic silica particle have a tendency to aggregate on the water front of the interface. Self-assembly of silica nanoparticles proceeds via the migration of these nanoparticles to the water–hydrocarbon interface followed by aggregation at the interface. Fractal-like morphologies of assembled silica nanoparticles at water–hydrocarbon interfaces are observed. Rapid assembly of the hydrophilic silica nanoparticles at water–hydrocarbon interfaces corresponds to an overall reduction in the surface tension of water–toluene and water–heptane systems. These studies demonstrate the silica aggregation that is the precursor of silica polymerization, or nucleation and growth is influenced by the presence of hydrocarbons in subsurface geologic environments. These insights were derived from in operando ultrasmall and small-angle X-ray scattering (USAXS/SAXS) measurements, cryo-scanning electron microscopy (Cryo-SEM) imaging, and classical molecular dynamics simulations. As a result, these studies are intended to inform current and future efforts aimed at tuning silica reactivity in subsurface geologic environments to enhance permeability, the design and use of silica-based proppants to enhance fractures, and the development of effective strategies to control silica-based scaling behavior in subsurface reservoirs.

42 ENGINEERING↗
DOE OSTI2024

Beam dynamics corrections to measurements of the muon anomalous magnetic moment

The Muon $g-2$ experiment at Fermilab is making progress towards its physics goal of measuring the muon anomalous magnetic moment with the unprecedented precision of 140 parts per billion. In April 2021, the collaboration published the first measurement based on the first year of data taking. The second result is based on the second and third years of data taking combined. We discuss the corrections to the anomalous spin precession signal due to beam dynamics effects being used to determine the anomalous spin precession frequency for the second result.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Electron-ion coincidence measurements of molecular dynamics with intense X-ray pulses

Molecules can sequentially absorb multiple photons when irradiated by an intense X-ray pulse from a free-electron laser. If the time delay between two photoabsorption events can be determined, this enables pump-probe experiments with a single X-ray pulse, where the absorption of the first photon induces electronic and nuclear dynamics that are probed by the absorption of the second photon. Here we show a realization of such a single-pulse X-ray pump-probe scheme on N 2 molecules, using the X-ray induced dissociation process as an internal clock that is read out via coincident detection of photoelectrons and fragment ions. By coincidence analysis of the kinetic energies of the ionic fragments and photoelectrons, the transition from a bound molecular dication to two isolated atomic ions is observed through the energy shift of the inner-shell electrons. Via ab-initio simulations, we are able to map characteristic features in the kinetic energy release and photoelectron spectrum to specific delay times between photoabsorptions. In contrast to previous studies where nuclear motions were typically revealed by measuring ion kinetics, our work shows that inner-shell photoelectron energies can also be sensitive probes of nuclear dynamics, which adds one more dimension to the study of light-matter interactions with X-ray pulses.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2024

Transient absorption measurements of excitonic dynamics in 3 R -MoS 2

The excitonic dynamics in MoS 2 monolayer, bilayer, and bulk flakes with different stacking orders, namely 3R and 2H, are investigated through transient absorption spectroscopy at room temperature. Samples are obtained by the mechanical exfoliation of bulk MoS 2 crystals with 3R and 2H stacking orders. Photoluminescence spectroscopy is performed to characterize and compare the samples. Time-resolved differential reflection measurements reveal that monolayer flakes exfoliated from the 3R and 2H crystals exhibit similar exciton lifetimes of a few picoseconds. However, the exciton lifetime in the 3R bilayer flake is approximately 85 ps, about twice as long as that in the 2H bilayer. This prolonged exciton lifetime is attributed to the reduction of the electron-hole wavefunction overlap in the 3R bilayer due to the built-in polarization. Similarly, in bulk 3R MoS 2 , the exciton lifetime is around 220 ps, approximately twice as long as those in bulk 2H MoS 2 . The extension of the exciton lifetime in 3R transition metal dichalcogenides could be advantageous for their applications in optoelectronic devices.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Topological order and entanglement dynamics in the measurement-only XZZX quantum code

We examine the dynamics of a ( 1 + 1 ) -dimensional measurement-only circuit defined by the stabilizers of the [[5,1,3]] quantum error correcting code interrupted by single-qubit Pauli measurements. The code corrects arbitrary single-qubit errors and it stabilizes an area law entangled state with a D 2 = Z 2 × Z 2 symmetry protected topological (SPT) order, as well as a symmetry breaking (SB) order from a twofold bulk degeneracy. The Pauli measurements break the topological order and induce a phase transition into a trivial area law phase. Allowing more than one type of Pauli measurement increases the measurement-induced frustration and the SPT and SB order can be broken either simultaneously or separately at nonzero measurement rate. This yields a rich phase diagram and unanticipated critical behavior at the phase transitions. Although the correlation length exponent ν = 4 3 and the dynamical critical exponent z = 1 are consistent with bond percolation, the prefactor of the logarithmic entanglement growth may take noninteger multiples of the percolation value. Remarkably, we identify a robust transient scaling regime for the purification dynamics of L qubits. It reveals a modified dynamical critical exponent z * ≠ z , which is observable up to times t ~ L z * and is reminiscent of the relaxation of critical systems into a prethermal state.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Apparatus and method for dynamic acousto-elasticity technique measurements at simulated subsurface pressures

An apparatus (10) and method for performing nonlinear elasticity measurements using the dynamic acousto-elasticity technique (DAET) at simulated subsurface conditions in the laboratory, are described. The current state-of-the-art for measuring nonlinear elasticity parameters using DAET is limited to ambient pressure conditions on the bench-top. The present invention permits nonlinear parameter measurements at controlled sample internal fluid pore pressures (52) and external confining stress (44), (50) conditions.

Roberts, Peter M.↗
DOE OSTI2023

Measurement of femtosecond dynamics of ultrafast electron beams through terahertz compression and time-stamping

Visualizing ultrafast dynamics at the atomic scale requires time-resolved characterization with femtosecond temporal resolution. For fully relativistic electron bunch probes, existing techniques for single-shot ultrafast electron diffraction (UED) are limited by the achievable electron probe bunch length, charge, and timing jitter. We present the first experimental demonstration of dual-fed THz-driven compression and time-stamping that enables electron probes with improved temporal resolution. This technique utilizes two counter-propagating quasi-single-cycle THz pulses generated from two OH-1 organic crystals coupled into an optimized THz compressor structure. We demonstrate electron bunch compression and time-of-arrival jitter suppression by a factor of 3 paving the way toward unique opportunities for UED time-resolved measurements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Simulation and measurement of the dynamic strain response in a prototypical spallation target

The Second Target Station (STS) at the Spallation Neutron Source (SNS) will address emerging scientific challenges by providing a source of intense cold neutrons to instruments optimized for this source. The STS target will use rotating tungsten blocks and will receive 1.3 GeV proton beam pulses from the SNS accelerator at a repetition rate of 15 Hz. The facility life is planned for 40 years, and each target assembly life is expected to be approximately 10 years. An accurate strain prediction is then critical for fatigue life assessment of STS target blocks because they will be subject to approximately 10 8 beam pulses per lifetime. As an R&D activity, the Los Alamos Neutron Science Center (LANSCE) Weapons Neutron Research (WNR) Target 2 (Blue Room) facility was used to test the strain response of prototypical target blocks to the thermal shock of a proton pulse. The blue room was well suited for a pulsed proton beam impact test of subscale STS target blocks; the 800 MeV proton energy is approximately 60 % of the 1.3 GeV proton energy expected from the SNS accelerator to the STS. The LANSCE Proton Storage Ring (PSR) and SNS are both short-pulse proton beam sources with nominal pulse widths of 250 ns and 661 ns, respectively, so the energy deposition in the target occurs in <1 μs pulse duration. Strain measurements on the outer surface of three target blocks (bare tungsten, tantalum-clad tungsten, niobium-clad tungsten) were recorded for comparison against neutronics and structural simulations. In conclusion, this experiment and the supporting simulations satisfied the following primary research goals for the STS target.

Dynamic strain response↗
DOE OSTI2023

Ultrafast transient absorption measurements of photocarrier dynamics in PdSe 2

We investigate the photocarrier dynamics in bulk PdSe 2 , a layered transition metal dichalcogenide with a novel pentagonal structure and unique electronic and optical properties. Using femtosecond transient absorption microscopy, we study the behavior of photocarriers in mechanically exfoliated bulk PdSe 2 flakes at room temperature. By employing a 400 nm ultrafast laser pulse, electron–hole pairs are generated, and their dynamics are probed using an 800 nm detection pulse. Our findings reveal that the lifetime of photocarriers in bulk PdSe 2 is approximately 210 ps. Furthermore, by spatially resolving the differential reflection signal, we determine a photocarrier diffusion coefficient of about 7.3 cm 2 s –1 . Based on these results, we estimate a diffusion length of around 400 nm and a photocarrier mobility of approximately 300 cm 2 V –1 s –1 . Furthermore, these results shed light on the ultrafast optoelectronic properties of PdSe 2 , offer valuable insights into photocarriers in this emerging material, and enable design of high-performance optoelectronic devices based on PdSe 2 .

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

Element- and Time-Resolved Measurements of Spin Dynamics Using X-ray Detected Ferromagnetic Resonance

Although XFMR experiments have been carried out at a number of synchrotron radiation facilities since 2004, only a few facilities currently have XFMR setups available for user operation. Here in this review, we mainly focus on recent developments and work that has been carried out using time-resolved XFMR at beamline 4.0.2 of the Advanced Light Source and at beamline I10 of the Diamond Light Source. The experimental setup and the sample holder used at beamline I10 and beamline 4.0.2, respectively, are shown in Figure 1. We will first introduce the working principle of XFMR and then provide examples of the capabilities of this technique. Finally, we will briefly describe an outlook for the future development of and new opportunities for XFMR.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗