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

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Transient absorption spectroscopy to explore cellular pathways to photobiomodulation

Photobiomodulation (PBM) describes the use of low irradiance light in the red to near-infrared wavelength range to stimulate biological effects in tissue, and many biological and spectroscopic techniques are used to study PBM. However, these techniques focus on the products or downstream effects rather than the electronic transitions that initiate the PBM processes. This study presents a novel approach to studying low irradiance light exposures on individual proteins and/or protein complexes by combining a continuous wave (CW) laser diode with femtosecond transient absorption spectroscopy (TAS), coined here as CW-TAS, and tests the system on reduced cytochrome c (Cyt c) for proof of principle. TAS was conducted using a 532-nm excitation pump beam and a 350-600 nm supercontinuum probe. In this work, CW laser diodes with wavelengths of 450 nm, 635 nm, and 808 nm were interchangeably fiber coupled into the HELIOS Fire. Samples of Cyt c were tested by TAS using a pump power of 15 µW, both with and without CW exposure. CW exposures were carried out with irradiances of 1.60 and 3.20 mW/cm 2 , except for 808 nm, which was only tested at 1.60 mW/cm 2 . Both kinetic and global analyses were performed on the TAS data and the time constants for sets with and without CW exposures were compared. The TAS data for Cyt c with the full dosage of CW exposures did not alter the TAS data distinguishably from the control data. No new electronic transient signals were observed beyond the background when testing Cyt c with the CW exposures. Kinetic analysis confirmed that existing transients did not deviate beyond uncertainty. Global time constants for Cyt c were calculated to be 0.25 ± 0.03 ps and 5.1 ± 0.3 ps for the control study, and the time constants for the CW exposed Cyt c were not significantly different. This study concludes that CW irradiation, at doses delivered, does not alter the transient absorption data of Cyt c. The CW-TAS method provides a new tool for studying PBM effects in other proteins and protein complexes, such as Complex IV, in future studies.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Improvement of the overall performances of LiMn{sub 2}O{sub 4} via surface-modification by polypyrrole

Graphical abstract: Polypyrrole(PPy) film has improved the rate performance of LiMn{sub 2}O{sub 4} efficiently due to its excellent conductivity. PPy@LiMn{sub 2}O{sub 4} could provide more energy under the higher power than pristine LMO. - Highlights: • The PPy layer on the surface of LMO particles hasn’t been studied in LiMn{sub 2}O{sub 4} so far. • The solvent in the synthesis process of PPy@LMO is absolute ethyl alcohol. • The differences of surface-modification between the PPy and PI for LMO. • The analyses of rate performances are through specific power. - Abstract: Polypyrrole (PPy) is an excellent conductive polymer and the study on its utilization in the surface modification of the LiMn{sub 2}O{sub 4} (LMO) is few. In this work, the structure, morphology and electrochemical performance of surface-modified LiMn{sub 2}O{sub 4} composites with PPy and polyimides (PI) were discussed. The crystal structure, chemical bonds and morphology were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. Moreover, the specific power and cycling performance were tested at room and high (55 °C) temperature. The PPy@LMO (surface-modified LMO composites with PPy) shows better performances than the pristine LMO. The addition of PPy not only weakens the corrosion caused by electrolyte, but also improves the discharge capacity at higher rates. The charge transfer resistance of the PPy@LMO is much lower than that of the pristine LMO after cycling.

36 MATERIALS SCIENCE↗
DOE OSTI2017

High energy neutron transmission analysis of dry cask storage

Since the U.S. currently only approves of storing used nuclear fuel in pools or dry casks, the demand for dry cask storage is on the rise due to the continuous operation of currently existing nuclear plants which are reaching or have reached the capacity of their used fuel pools. With the rising demand comes additional pressure to ensure the integrity of dry cask systems. Visual inspection is costly and man-power intensive, so alternative nondestructive testing techniques are desired to insure the continued safe and effective storage of fuel. One such approach being investigated by the University of Florida is neutron based computed tomography. Simulations in MCNP are preformed where D-T energy neutrons are transmitted through the dry cask and measured on the opposite side. If the transmitted signal is clear enough, the interior of the cask can be reconstructed from the measurement of the alterations of neutron signal intensity using standard mathematical techniques developed for medical imaging. Preliminary efforts show a correlation between energy and number of scatters (which is an indication of retention of position information). Work is ongoing to quantify if the correlation is strong enough that an energy discriminator may be used as a filter in future image reconstruction. The calculated transmission probability suggests that an image could be reconstructed with a week of scanning.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Hot QCD phase diagram from holographic Einstein–Maxwell–Dilaton models

In this review, we provide an up-to-date account of quantitative holographic descriptions of the strongly coupled quark-gluon plasma (QGP) produced in heavy-ion collisions, based on the class of gauge-gravity Einstein-Maxwell-Dilaton (EMD) models. Holography is employed to tentatively map the QCD phase diagram at finite temperature onto a dual theory of charged, asymptotically AdS black holes in 5D. With a quantitative focus on the hot QCD phase diagram, the EMD models reviewed are adjusted to describe lattice results for the finite-temperature QCD equation of state, with 2+1 flavors and physical quark masses, at zero chemical potential and vanishing electromagnetic fields. The predictive power of EMD models is tested by quantitatively comparing their predictions for the hot QCD equation of state at nonzero baryon density and the corresponding state-of-the-art lattice QCD results. The shear and bulk viscosities predicted by these EMD models are also compared to the corresponding profiles favored by the latest phenomenological multistage models describing different heavy-ion data. We report preliminary results from a Bayesian analysis which provide systematic evidence that lattice results at finite temperature and zero baryon density strongly constrains the free parameters of EMD models. Remarkably, the set of parameters constrained by lattice results at zero chemical potential produces EMD models in quantitative agreement with lattice QCD results also at finite baryon density. We also review results for equilibrium and transport properties from magnetic EMD models, describing the QGP at finite temperatures and magnetic fields. Lastly, we provide a critical assessment of the main limitations and drawbacks of the holographic models reviewed in the present work, and point out some perspectives we believe are of fundamental importance for future developments.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

MUTZ-3 derived Langerhans cells in human skin equivalents show differential migration and phenotypic plasticity after allergen or irritant exposure

After allergen or irritant exposure, Langerhans cells (LC) undergo phenotypic changes and exit the epidermis. In this study we describe the unique ability of MUTZ-3 derived Langerhans cells (MUTZ-LC) to display similar phenotypic plasticity as their primary counterparts when incorporated into a physiologically relevant full-thickness skin equivalent model (SE-LC). We describe differences and similarities in the mechanisms regulating LC migration and plasticity upon allergen or irritant exposure. The skin equivalent consisted of a reconstructed epidermis containing primary differentiated keratinocytes and CD1a{sup +} MUTZ-LC on a primary fibroblast-populated dermis. Skin equivalents were exposed to a panel of allergens and irritants. Topical exposure to sub-toxic concentrations of allergens (nickel sulfate, resorcinol, cinnamaldehyde) and irritants (Triton X-100, SDS, Tween 80) resulted in LC migration out of the epidermis and into the dermis. Neutralizing antibody to CXCL12 blocked allergen-induced migration, whereas anti-CCL5 blocked irritant-induced migration. In contrast to allergen exposure, irritant exposure resulted in cells within the dermis becoming CD1a{sup −}/CD14{sup +}/CD68{sup +} which is characteristic of a phenotypic switch of MUTZ-LC to a macrophage-like cell in the dermis. This phenotypic switch was blocked with anti-IL-10. Mechanisms previously identified as being involved in LC activation and migration in native human skin could thus be reproduced in the in vitro constructed skin equivalent model containing functional LC. This model therefore provides a unique and relevant research tool to study human LC biology in situ under controlled in vitro conditions, and will provide a powerful tool for hazard identification, testing novel therapeutics and identifying new drug targets. - Highlights: • MUTZ-3 derived Langerhans cells integrated into skin equivalents are fully functional. • Anti-CXCL12 blocks allergen-induced MUTZ-LC migration. • Anti-CCL5 blocks irritant-induced MUTZ-LC migration. • Irritant mediated MUTZ-LC trans-differentiation to macrophage-like cell in dermis. • Trans-differentiation of MUTZ-LC is IL-10 dependent.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Connecting Interfacial Mechanical Adhesion, Efficiency, and Operational Stability in High Performance Inverted Perovskite Solar Cells

Carbazole-based self-assembled monolayers (SAMs) at the interface between the metal-halide perovskite (MHP) and the transparent conducting oxide (TCO) serve the function of hole-transport layers in p-i-n "inverted" perovskite solar cells (PSCs). In this report we show that the use of an iodine-terminated carbazole-based SAM increases the interfacial mechanical adhesion dramatically (2.6-fold) and that this is responsible for substantial improvements in the interfacial morphology, photocarrier transport, and operational stability. While the improved morphology and optoelectronic properties impart high efficiency (up to 25.39%) to the PSCs, the enhanced adhesion suppresses nucleation and propagation of pores/cracks during PSC operation, resulting in the retention of 96% of the initial efficiency after 1000 h of continuous-illumination testing at the maximum power-point. This demonstrates the strong connection between judicious interfacial adhesion toughening and simultaneous enhancement in the efficiency and operational stability of p-i-n PSCs, with broader implications for the reliability and durability of perovskite photovoltaics before they can be commercialized.

14 SOLAR ENERGY↗
DOE OSTI2018

Confinement and asymptotic freedom with Cooper pairs

One of the most profound aspects of the standard model of particle physics, the mechanism of confinement binding quarks into hadrons, is not sufficiently understood. The only known semiclassical mechanism of confinement, mediated by chromo-electric strings in a condensate of magnetic monopoles still lacks experimental evidence. Here we show that the infinite resistance superinsulating state, which emerges on the insulating side of the superconductor insulator transition in superconducting films offers a realization of confinement that allows for a direct experimental access. We find that superinsulators realize a single-color version of quantum chromodynamics and establish the mapping of quarks onto Cooper pairs. We reveal that the mechanism of superinsulation is the linear binding of Cooper pairs into neutral “mesons” by electric strings. Here, our findings offer a powerful laboratory for exploring and testing the fundamental implications of confinement, asymptotic freedom, and related quantum chromodynamics phenomena via the desktop experiments on superconductors.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Binary particle swarm optimisation‐based optimal substation coverage algorithm for phasor measurement unit installations in practical systems

Phasor measurement units (PMUs) play an important role in the wide‐area monitoring and protection of modern power systems. Historically, their deployment was limited by the prohibitive cost of the device itself. Therefore, the objective of the conventional optimal PMU placement problem was to find minimum number of devices, which when carefully placed throughout the network, maximised observability subject to different constraints. Due to improvements in relay technology, digital relays can now serve as both relays and PMUs. Under such circumstances, the substation installations consume the largest portion of the deployment cost, and not the devices themselves. Thus, for minimising cost of synchrophasor deployment, number of substation installations must be minimised. This study uses binary particle swarm optimisation to minimise number of substations in which installations must be performed for making all voltage levels observable, while being subject to various practical constraints. Standard IEEE systems have been used to explain the technique. Finally, a large‐scale network of Dominion Virginia Power is used as the test bed for implementation.

Mishra, Chetan↗
DOE OSTI2014

Development of soft X-ray polarized light beamline on Indus-2 synchrotron radiation source

This article describes the development of a soft x-ray beamline on a bending magnet source of Indus-2 storage ring (2.5 GeV) and some preliminary results of x-ray absorption spectroscopy (XAS) measurements using the same. The beamline layout is based on a spherical grating monochromator. The beamline is able to accept synchrotron radiation from the bending magnet port BL-1 of the Indus-2 ring with a wide solid angle. The large horizontal and vertical angular acceptance contributes to high photon flux and selective polarization respectively. The complete beamline is tested for ultrahigh vacuum (UHV) ∼ 10{sup −10} mbar. First absorption spectrum was obtained on HOPG graphite foil. Our performance test indicates that modest resolving power has been achieved with adequate photon flux to carry out various absorption experiments.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Development of C{sup 6+} laser ion source and RFQ linac for carbon ion radiotherapy

A prototype C{sup 6+} injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Optimization of the N ∥ Upshift in the DIII-D high field side lower hybrid current drive experiment

High field side lower hybrid current drive (LHCD) is one potential candidate for efficient non-inductive current drive in tokamak power plants, and the first test of this technology will occur on the DIII-D tokamak during the 2024 campaign. Previous LFS launch experiments operated in the multi-pass regime and relied on scrape-off layer interactions to close the spectral gap. In the DIII-D experiment, single-pass damping is achievable via an upshift in the parallel refractive index N ∥ caused by mode converting twice (slow → fast → slow). This mode conversion affects the ray trajectories and can lead to enhanced N ∥ upshift depending on where mode conversion occurs. Compared to multi-pass absorption experiments, the optimization of launched N ∥ and plasma parameters can be counter-intuitive: increased density may increase efficiency and smaller N ∥,launch tend to damp closer to the separatrix. A hard x-ray camera installed to measure the bremsstrahlung (50–250 keV) radiation from LHCD-generated fast electrons is capable of verifying the trends reporting in this paper through comparison to the ray-tracing/Fokker–Planck codes GENRAY/CQL3D.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Three-Phase LCC-LCC Compensated 50-kW Wireless Charging System with Non-Zero Interphase Coupling

In this paper, an LCC-LCC compensated 50 kW 3phase (3φ) wireless charging system with nonzero interphase mutual inductance is demonstrated. The 3φ-LCC compensation is designed considering a nonzero mutual-inductance among the phase-coils to meet resonance criteria, balance voltages and currents of the resonant tank components, achieve desired voltage gain, and ensure the zero-voltage switching (ZVS) operation. An experimental prototype of the 3φ-LCC-LCC compensation circuit is built for a 50 kW bipolar coil-based 3φ wireless charging system. The prototype system was tested at rated 50 kW power for evaluating the efficiency, ZVS operation, electric and magnetic field emissions, and thermal characteristics. The experimental results show 94.3% dc-to-dc efficiency and only 4.4 μT rms magnetic field emission at the rated 50 kW output power.

Mohammad, Mostak↗
DOE OSTI2019

Pulsed Resonant Charging Power Supply for the Spallation Neutron Source Extraction Kicker PFN System

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory uses fourteen pulsed modulators in the extraction system to deflect the proton beam from the accumulation ring to the target. Each individual pulse modulator is a pulse-forming network (PFN) located in a service building external to the ring tunnel. SNS is in the planning and development phase of a proton power upgrade (PPU) to increase the beam energy from 1.0 to 1.3 GeV, and the extraction system is required to provide the same deflection at the higher beam energy. Increasing the magnet current, by charging the PFN to a higher voltage, by 20% will provide the required deflection. The existing capacitor charging power supply is incapable of charging the PFN to higher voltages between the 60 Hz pulses; therefore, a new resonant charging scheme has been developed to charge to the PPU higher voltage within the available time. This paper describes the resonant charging power supply design and presents test results from a prototype operating on a full system test stand.

Saethre, Robert↗
DOE OSTI2021

Superconducting Magnet Qualification Methodology for the Material Plasma Exposure Experiment

The Material Plasma Exposure eXperiment (MPEX), currently under design, is a new linear plasma device to advance the understanding of plasma-material interactions through the generation and delivery of plasmas as they are expected in future fusion reactor divertors. MPEX will be a steady-state device to study high-fluence exposures of plasma-facing materials and components. The requirements for the magnetic field at the target and the heating stages make the application of superconducting coils necessary. Conceptual designs for the superconducting magnets have been developed, and multiple cryostats with warm bore diameters of either 65 cm or 156 cm are envisioned to facilitate their integrated and timely assembly with other systems such as vacuum, water cooling, and RF power. Although design, fabrication, and testing for the magnets as stand-alone units are straightforward, challenges will arise during the integration of the system. Two different field profiles will be used during operation. The magnetic field where the electron cyclotron heating occurs needs to operate at both 1.25 and 2.5 T. It is critical that the magnets all share the same magnetic axis and alignment. The mutual inductance between cryostats will affect the quench behavior of the system. Also, cryostat-to-cryostat forces can be as large as 700 kN, and the magnitude and direction will change depending on which coils are energized. The design of the system must take those characteristics into account along with the quench scenarios. This paper describes the qualification approach that will be used to determine whether stand-alone tests can be used to ensure the success of the integrated system. Fiducials will be used to define the location of the magnetic axis for each cryostat to ensure proper alignment. Quench tests of a single magnet will be performed at a current above the normal operating current to account for additional stored energy from the mutual inductance to adjacent cryostats. Also, a 1018 steel plate will be mounted on either end of a cryostat to simulate the cryostat-to-cryostat forces. Requirements for the size and location of the steel plates are described.

Burkhardt, Earle↗
DOE OSTI2012

On Evaluating Cycling and Movement of Conventional Generators for Balancing Services with Large Solar Penetration

Abstract— The increasing uncertainty caused by a higher penetration level of renewable energy points to the need for sufficient balancing services to ensure secure operation. It is thus of necessity to accurately quantify these services and evaluate the cycling and movement of conventional generators providing load following and regulation services for optimally planning and scheduling multiple resources. This paper first introduces a systematic approach to calculating load following and regulation requirements with a large amount of solar integration. Then, two methods to quantitatively determine the cycling of conventional generators are proposed, including (1) mileage and number of direction changes in balancing service and (2) ramp statistics (or half-cycle) analysis. The proposed methods are tested on the NV Energy power system model. Simulation results demonstrate a significant impact of increased solar capacity on balancing service and cycling of conventional generators. Busy hours are identified for different study scenarios with various solar penetration levels. This study provides a basis for evaluating the wear and tear of the conventional generators in the solar integration process in the Nevada power system. Index Terms—balancing requirement, conventional generator, cycling and movement, load following, regulation, renewable energy, solar integration

ok↗
DOE OSTI2018

Combining Simulation and Emulation Systems for Smart Grid Planning and Evaluation

Software-defined networking (SDN) enables efficient network management. As the technology matures, utilities are looking to integrate those benefits to their operations technology (OT) networks. To help the community to better understand and evaluate the effects of such integration, we develop DSSnet, a testing platform that combines a power distribution system simulator and an SDN-based network emulator for smart grid planning and evaluation. DSSnet relies on a container-based virtual time system to achieve efficient synchronization between the simulation and emulation systems. To enhance the system scalability and usability, we extend DSSnet to support a distributed controller environment. To enhance system fidelity, we extend the virtual time system to support kernel-based switches. In conclusion, we also evaluate the system performance of DSSnet and demonstrate the usability of DSSnet with a resilient demand response application case study.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

System Validation Platform Working Directories

A suite of software tools used to interface with power electronic equipment for laboratory testing and device certification. They are typically used as equipment drivers with using the System Validation Platform (SVP) graphical user interface (GUI). Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2021-1185 O

Johnson, JayT↗