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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 1,603 records · Page 89
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

The Multiple Use Plug Hybrid for NanoSats (MUPHyN) Miniature Thruster

The Multiple Use Plug Hybrid (for) Nanosats is a prototype thruster is being developed to fill a niche application for NanoSat-scale spacecraft propulsion. When fully developed, the MUPHyN thruster will provide an effective and low-risk propulsive capability that could enable multiple NanoSats to be independently re-positioned after deployment from a parent launch vehicle. Because the environmentally benign, chemically-stable propellants are mixed only within the combustion chamber after ignition and the flow rate of the fuel is determined by a pyrolysis mechanism that is nearly independent of pressure or fuel grain defects, the system is inherently safe and can be piggy-backed near a secondary payload with little or no overall mission risk increase to the primary payload. The MUPHyN thruster uses safe-handling and inexpensive nitrous oxide (N2O) and acrylonitrile-butadiene-styrene (ABS) as propellants. Fused Deposition Modeling (FDM), a direct digital manufacturing process, is used to fabricate short-form-factor solid fuel grains with multiple helical combustion ports from ABS thermoplastic. This manufacturing process allows for the rapid development and manufacture of complex fuel grain geometries that are not possible to extrude or cast using conventional methods. This technology enables the construction of fuel grains with length-to-diameter ratios appropriate for incorporation into CubeSats while maintaining high surface areas and regression rates that allow the system to maintain a near optimal oxidizer to fuel ratio. The MUPHyN system provides attitude control torques by using secondary-injection thrust vectoring on a truncated aerospike nozzle. This configuration allows large impulse delta V burns and small impulse attitude control firings to be performed with the same system. To ensure survivability during extend duration burns, the MUPHyN incorporates a novel regenerative cooling design where the N2O oxidizer flows through a cooling path embedded in the aerospike nozzle before being injected into the combustion chamber near the nozzle base.

Eilers, Shannon D.↗
NASA NTRS1972

California coast nearshore processes study

The author has identified the following significant results. In the Santa Barbara Channel the effect of the California and the Anacapa Currents are clearly seen in image 1109-18073M. The large triangular shaped lobe of suspended particulate matter that stretches almost to Anacapa Island from the Ventura River area is disrupted approximately midchannel by the east-moving Anacapa Current. In the Point Conception area a lobe of suspended material approximately 20 miles long can be seen moving eastward as a result of the California Current. In the San Francisco Bay area the major results include the detection and delineation of the San Francisco Bay, the location and vector of suspended sediment in the San Francisco Bay, and the ability to differentiate morphologic units within the San Francisco Bay tidelands. Several densitometer line traces seaward of the Golden Gate Bridge on image 1075-18173-4 outline the San Francisco Bay and give evidence of good water penetration.

Pirie, D. M.↗
DOE OSTI2023

Anatomy of an agricultural antagonist: Feeding complex structure and function of three xylem sap‐feeding insects illuminated with synchrotron‐based 3D imaging

Abstract Many insects feed on xylem or phloem sap of vascular plants. Although physical damage to the plant is minimal, the process of insect feeding can transmit lethal viruses and bacterial pathogens. Disparities between insect‐mediated pathogen transmission efficiency have been identified among xylem sap‐feeding insects; however, the mechanistic drivers of these trends are unclear. Identifying and understanding the structural factors and associated integrated functional components that may ultimately determine these disparities are critical for managing plant diseases. Here, we applied synchrotron‐based X‐ray microcomputed tomography to digitally reconstruct the morphology of three xylem sap‐feeding insect vectors of plant pathogens: Graphocephala atropunctata (blue‐green sharpshooter; Hemiptera, Cicadellidae) and Homalodisca vitripennis (glassy‐winged sharpshooter; Hemiptera, Cicadellidae), and the spittlebug Philaenus spumarius (meadow spittlebug; Hemiptera, Aphrophoridae). The application of this technique revealed previously undescribed anatomical features of these organisms, such as key components of the salivary complex. The visualization of the 3D structure of the precibarial valve led to new insights into the mechanism of how this structure functions. Morphological disparities with functional implications between taxa were highlighted as well, including the morphology and volume of the cibarial dilator musculature responsible for extracting xylem sap, which has implications for force application capabilities. These morphological insights will be used to target analyses illuminating functional differences in feeding behavior.

3D imaging↗
DOE OSTI2025

Increasing the Scale of the Mass Spectrometry Query Language Compendium with Explainable AI

A significant bottleneck in metabolomics data interpretation is the effective use of domain knowledge to assign structural information based on fragmentation patterns. The mass spectrometry query language (MassQL) aims to make this process accessible and applicable across multiple analysis platforms. While advanced computational methods are capable of predicting compound structures from fragmentation data, AI/ML approaches often rely on complex, opaque criteria that are difficult to interpret or modify. As a result, their predictive patterns cannot be readily translated into human-readable rules, such as those used in MassQL. Here, in this study, we introduce ChemEcho, a machine learning embedding method that converts tandem mass spectrometry data into sparse feature vectors containing peak and neutral mass subformulae to enhance explainable AI/ML-based methods. An advantage of this approach is that decision trees trained using these feature vectors can be directly translated to MassQL. Using a battery of decision trees trained using ChemEcho embeddings to predict molecular attributes, we generated over 1500 MassQL queries for 765 molecular features and evaluated their precision and recall. From these queries, the 50 highest-performing queries were integrated into the MassQL compendium. This set of generated MassQL queries included environmentally and biologically relevant classes such as PFAS and molecules containing phosphate or sulfate substructures. To illustrate the impact these queries would have on a typical metabolomics experiment, these MassQL queries were applied to a public metabolomics data set─resulting in a marked increase in the structural information derived from tandem mass spectra. Access and reuse of these queries is expected to enhance structural annotation in untargeted experiments, leading to more specific claims and advancing many applications in metabolomics.

Harwood, Thomas V. [USDOE Joint Genome Institute (↗
DOE OSTI2023

The plasma–sheath transition and Bohm criterion in a high recycling divertor

The high recycling regime of a divertor is characterized by high plasma particle fluxes and low temperature at the target, where a strong hydrogen recirculation loop exists. Atomic processes in the high recycling regime, such as ion–neutral friction and radiation, can affect the plasma momentum and energy transport in the sheath transition region. Here, in this work, the plasma–sheath transition near a high recycling wall is investigated. The Bohm speed, which constraints the ion exit flow speed, is evaluated from a transport model that accounts for the effect of the anisotropic transport and atomic collisions in the transition layer. A first principles kinetic code vector particle-in-cell with the atomic collision package is used to investigate a 1D self-consistent slab plasma with a high recycling boundary for the tungsten and carbon divertors. The results demonstrate the accuracy of the Bohm speed model in predicting the ion exit flow speed in the transition region, as well as the reduction of the Bohm speed due to the ion–neutral friction. The effect of different wall materials, tungsten, and carbon, on the Bohm speed and near-wall plasma profile is shown.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2017

Search for dark matter at $\sqrt{s}=13~\mathrm{TeV}$ TeV in final states containing an energetic photon and large missing transverse momentum with the ATLAS detector

Results of a search for physics beyond the Standard Model in events containing an energetic photon and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. As the number of events observed in data, corresponding to an integrated luminosity of 36.1 fb –1 of proton–proton collisions at a centre-of-mass energy of 13 TeV, is in agreement with the Standard Model expectations, model-independent limits are set on the fiducial cross section for the production of events in this final state. Exclusion limits are also placed in models where dark-matter candidates are pair-produced. For dark-matter production via an axial-vector or a vector mediator in the s-channel, this search excludes mediator masses below 750–1200 GeV for dark-matter candidate masses below 230–480 GeV at 95% confidence level, depending on the couplings. In an effective theory of dark-matter production, the limits restrict the value of the suppression scale M * to be above 790 GeV at 95% confidence level. A limit is also reported on the production of a high-mass scalar resonance by processes beyond the Standard Model, in which the resonance decays to Zγ and the Z boson subsequently decays into neutrinos.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Building heights and urban canopy parameters for urban modeling

GLObal Building heights for Urban Studies (UT-GLOBUS) is a random forest model based framework that provides a level-of-detail-1 (LoD-1) building height dataset. The primary objective of UT-GLOBUS is not to precisely predict the height and footprint of individual buildings, but rather to offer a functional framework for generating building level information using open-source datasets for modeling applications. Specifically, UT-GLOBUS is tailored to meet the requirements of deriving urban canopy parameters (UCPs) for the multi-layer model within the Weather Research and Forecasting (WRF) model and building heights for the SOLWEIG and SUEWS model. Building-level data is accessible in vector file format (GeoPackage: .gpkg), which can be converted into raster file format (geoTIFF). The vector files employ the Universal Transverse Mercator (UTM) projection. The vector files are compatible with GIS platforms like QGIS and ArcGIS, and can be imported for analysis using programming languages such as Python. We are also providing UCPs required by the multi-layer urban model in the urban WRF in binary file format. Additionally, we provide the urban fractions calculated using ESA world cover dataset (https://esa-worldcover.org/en) for WRF model in binary file format. These binary files can be directly incorporated into the WRF pre-processing system (WPS).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

A Planar-Cavity Receiver Configuration for High-Temperature Solar Thermal Processes: Preprint

Next generation concentrating solar thermal power (CSP) and novel solar thermochemical systems using concentrating solar thermal (CST) energy require high operating temperatures exceeding those of traditional nitrate-salt CSP systems. Particle-based systems are attractive for next-generation CSP and CST applications owing to high-temperature stability of inert silica- or alumina-based particulate materials, the lack of low-temperature freezing concerns that limit molten salt and/or molten metal heat transfer media, and cost-effective thermal storage using low-cost particulate and containment materials. Open-cavity falling particle receivers have many potential advantages, but face challenges pertaining to scalability, thermal loss, and particle loss through the open aperture, and are infeasible for chemical processes that require a low-oxygen ambient environment. Enclosed receiver configurations can be scalable, avoid particle loss when heating particles, and have potential for future chemical processes; however, particle-based heat transfer media provide substantially lower heat transfer rates than liquid media, and thus enclosed particle receiver designs require novel configurations to limit surface temperatures under the high incident solar flux concentrations necessary for high receiver thermal efficiency at high temperature. This paper introduces the novel planar-cavity enclosed particle receiver configuration in which arrays of planar surfaces are arranged into sub-vertical cavities. Large angles between the panel surface normal vectors and the aperture surface normal allow the incoming solar beam to distribute along the panel walls. Correspondingly, a high incident solar flux concentration at the cavity aperture produces substantially lower absorbed solar flux concentration on any panel wall. Sets of individual vertical cavities can be arranged to form a scalable receiver configuration.

cavity receiver↗
NASA NTRS1987

Lower thermosphere wind regime according to radiometeor measurements in Kazan

Research in dynamic processes in the lower thermosphere has been carried out in Kazan using the meteor radar facilities of the Kazan State University under the MAP-GLOBMET international program. Presented is experimental data on seasonal dependences of the wind for anomalous winter circulation periods, spring and autumn reconstructions and stable summer circulation from observations conducted in 1978 to 1984. Prevailing wind parameters are shown: zonal and meridional component amplitudes and A sub 0 and azimuth of the prevailing wind vector. The values are also presented for semidiurnal zonal and meridional tidal components, their correlation coefficient and zonal component amplitude maximum time.

Sidorov, V. V.↗
DOE OSTI2020

Development of a Reference Design for a Cyber-Physical System

The purpose of this thesis is to develop a reference design to assist in the selection of security practices in power electronics design. A prototype will be developed from this reference design for evaluation. This evaluation will include a brief cost/benefit analysis to gauge the efficacy of implementing each layer of security throughout the power electronics design process. This thesis will also describe the obstacles and effectiveness of integrating a Trusted Platform Module (TPM) into a cyber-hardened grid-connected device. The TPM device is a secured crypto processor that assists in generating, storing, and restricting the use of cryptographic keys. The emphasis of this research is to establish integrity, authenticity, and confidentiality within a system by providing a baseline of security concerns for segments of the system. This research considers communication, control, and hardware level securities. The scope of this thesis will review the necessary security methods as well as consider the effects these methods have on the embedded system, to assess the desired security to responsiveness trade off. Applying this approach to a design process will alleviate various unknowns of appending security to a power electronics design. This thesis describes the specific vulnerabilities introduced within this grid-edge environment, and how the liabilities within the system can be mitigated. Initially, common security techniques will be considered to establish a guideline to benchmark performance and resource costs of the system. The foundation will be a non-hardened power electronic system platform with industry standard communication protocols. Several security techniques and attack vectors will then be evaluated to contribute to the base level platform. Other fail-safe features take place to gauge progress of the selected approach, non-inclusive to the TPM. Collectively, this investigation will determine a valid experiment by appraising and categorizing resource allocation, performance overhead, and monetary cost analysis results into a reference design. The prototype will then demonstrate methods to relieve common threats that are purposefully implemented into the design.

Blair, Nicholas Paul↗
DOE OSTI2022

A resistive MHD model and simulation on plasma flow evolution in the presence of resonant magnetic perturbation in a tokamak

Nonaxisymmetric magnetic fields such as the intrinsic error field and the externally applied resonant magnetic perturbation (RMP) in a tokamak are known to influence the plasma momentum transport and flow evolution through plasma response, which itself strongly depends on the plasma flow as well. The nonlinear interaction between plasma response and flow has been previously modeled in the conventional error field theory with the “no-slip” condition, which has been recently extended to allow the “free-slip” condition. In this work, we further target this specific process and numerically simulate the nonlinear plasma response and flow evolution in the presence of a single-helicity RMP in a circular-shaped model tokamak configuration, based on the full resistive MHD model in the initial-value code NIMROD. Time evolution of the parallel (to k) flow or “slip frequency” profile and its asymptotic steady state obtained from the NIMROD simulations are compared with both conventional and extended nonlinear response theories. Here, k is the wave vector of the propagating island. Good agreement with the extended theory with free-slip condition has been achieved for the parallel flow profile evolution in response to RMP in all resistive regimes, whereas the difference from the conventional theory with the no-slip condition tends to diminish as the plasma resistivity approaches zero.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Dark matter isocurvature from curvature

Isocurvature fluctuations, where the relative number density of particle species spatially varies, can be generated from initially adiabatic, or curvature, fluctuations if the various species fall out of or were never in thermal equilibrium. The freezing of the thermal relic dark matter abundance is one such case, but for modes that are still outside the horizon the amplitude is highly suppressed and originates from the small change in the local expansion rate due to the local space curvature produced by the curvature fluctuation. We establish a simple separate-universe method for calculating this generation that applies to both freeze-in and freeze-out models, identify three critical epochs for this process, and give general scaling behaviors for the amplitude in each case: the freezing epoch, the kinetic decoupling epoch and matter-radiation equality. Freeze-out models are typically dominated by spatially modulated annihilation from the latter epochs and can generate much larger isocurvature fluctuations compared with typical freeze-in models, albeit still very small and observationally allowed by cosmic microwave background measurements. Here, we illustrate these results with concrete models where the dark matter interactions are vector or scalar mediated.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

A dispersive analysis of $$\varvec{\eta '\rightarrow \pi ^+\pi ^-\gamma }$$ and $$\varvec{\eta '\rightarrow \ell ^+\ell ^-\gamma }$$

Abstract We present a dispersive representation of the $$\eta '$$ η ′ transition form factor that allows one to account, in a consistent way, for the effects of $$\rho $$ ρ – $$\omega $$ ω mixing in both the isoscalar and the isovector contributions. Using this formalism, we analyze recent data on $$\eta '\rightarrow \pi ^+\pi ^-\gamma $$ η ′ → π + π - γ to constrain the isovector part of the form factor, individually and in combination with data for the pion vector form factor, which suggests a tension in the $$\rho $$ ρ – $$\omega $$ ω mixing parameter. As a first application, we use our results, in combination with the most recent input for the isoscalar part of the form factor, to predict the corresponding spectrum of $$\eta '\rightarrow \ell ^+\ell ^-\gamma $$ η ′ → ℓ + ℓ - γ , in particular we find the slope parameter $$b_{\eta '}=1.455(24)\,\text {GeV}^{-2}$$ b η ′ = 1.455 ( 24 ) GeV - 2 . With forthcoming data on the latter process, our results establish the necessary framework to improve the evaluation of the $$\eta '$$ η ′ -pole contribution to the anomalous magnetic moment of the muon using experimental input from both $$\eta '$$ η ′ decay channels.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Dimension Reduction and Redundancy Removal through Successive Schmidt Decompositions

Quantum computers are believed to have the ability to process huge data sizes, which can be seen in machine learning applications. In these applications, the data, in general, are classical. Therefore, to process them on a quantum computer, there is a need for efficient methods that can be used to map classical data on quantum states in a concise manner. On the other hand, to verify the results of quantum computers and study quantum algorithms, we need to be able to approximate quantum operations into forms that are easier to simulate on classical computers with some errors. Motivated by these needs, in this paper, we study the approximation of matrices and vectors by using their tensor products obtained through successive Schmidt decompositions. We show that data with distributions such as uniform, Poisson, exponential, or similar to these distributions can be approximated by using only a few terms, which can be easily mapped onto quantum circuits. The examples include random data with different distributions, the Gram matrices of iris flower, handwritten digits, 20newsgroup, and labeled faces in the wild. Similarly, some quantum operations, such as quantum Fourier transform and variational quantum circuits with a small depth, may also be approximated with a few terms that are easier to simulate on classical computers. Furthermore, we show how the method can be used to simplify quantum Hamiltonians: In particular, we show the application to randomly generated transverse field Ising model Hamiltonians. The reduced Hamiltonians can be mapped into quantum circuits easily and, therefore, can be simulated more efficiently.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1972

Spectral and polarization analysis of micropulsations observed at ATS-1

Results are reported for an analysis of low frequency oscillations in the earth's magnetic field as observed at the synchronous orbit by the magnetometer experiment on board ATS 1. Oscillations in the range .002 f .02 H3 for the period Dec. 1966 through Dec. 1967 were studied. The analysis combines a detailed, computer-processed, spectral analysis of selected events with a less detailed manual analysis of all events in the two year time interval from Dec. 1966 to Dec. 1968. The computer analysis revealed that a given event is often characterized by a dominat, narrow, spectral peak whose associated oscillations are almost entirely limited to a plane, together with several minor peaks. Dynamic spectral analyses revealed that minor spectral peaks appear as short isolated bursts. The sense of rotation of the perturbation vector tends to change from right-handed elliptical at the beginning of a burst to left-handed elliptical at the end. The major axis of the polarization ellipse is inclined by typically 30 deg east of radial.

Morris, W.↗
NASA NTRS2008

Radio Frequency Compatibility of an RFID Tag on Glideslope Navigation Receivers

A process is demonstrated to show compatibility between a radio frequency identification (RFID) tag and an aircraft glideslope (GS) radio r eceiver. The particular tag chosen was previously shown to have significant spurious emission levels that exceeded the emission limit in th e GS aeronautical band. The spurious emissions are emulated in the study by capturing the RFID fundamental transmission and playing back th e signal in the GS band. The signal capturing and playback are achiev ed with a vector signal generator and a spectrum analyzer that can output the in-phase and quadrature components (IQ). The simulated interf erence signal is combined with a GS signal before being injected into a GS receiver#s antenna port for interference threshold determination . Minimum desired propagation loss values to avoid interference are then computed and compared against actual propagation losses for severa l aircraft.

Nguyen, Truong X.↗
NASA NTRS2024

Piezoelectric impedance-based high-accuracy damage identification using sparsity conscious multi-objective optimization inverse analysis

Two elements are essential in structural health monitoring utilizing dynamic responses: response measurement with high-frequency contents, i.e., small characteristic wavelengths, that can adequately reflect damage features, and effective inverse identification analysis that is however oftentimes under-determined. The advancement of smart structure integration has led to active interrogation through frequency-sweeping piezoelectric impedance measurement at high frequency range. In this research we develop a multi-objective optimization formulation for the identification of damage location and severity utilizing piezoelectric impedance. While one optimization objective is to match the response measurement with finite element model prediction in the damage parametric space, the other is the number of locations of damage, i.e., the sparsity of damage index as the solution vector, since damage usually occurs within a small number of locations. This multi-objective formulation fits well the under-determined nature of damage identification, as it naturally provides multiple solutions as basis for further elucidation. The challenge remaining is how to find a small solution set that can include the actual damage scenario. Here we develop a novel inverse identification framework utilizing the intelligent swarm optimizer which possesses flexibility for enhancement. We first embed a sparsity enforcement process into the population generation of the optimizer, which yields a solution repository intrinsically possessing sparsity. We then apply reinforcement learning so the agents can adaptively opt for local strategies with the aim of enriching the searching patterns to diversify the solutions. Through the incorporation of a Q-table, searching toward more promising directions will be rewarded. Our case analyses employing experimental data indicate that this sparsity-conscious multi-objective particle swarm optimization technique can lead to a small solution set which generally encompasses the true damage scenario. This effectively solves the structural damage identification problem with piezoelectric impedance measurement.

Yang Zhang↗
DOE OSTI2019

Creating Cybersecurity Professionals of the Future

Cybersecurity is a growing public concern with more threats and vulnerabilities being discovered and exploited by adversaries each day. In particular, industrial control systems (ICS) are at a higher risk because their components were not designed with cybersecurity in mind. With increased risk to ICS, it is vital that the employees who work on the system are trained in cybersecurity best practices and the latest threats. Research has shown that there are currently no curriculum standards for an ICS cybersecurity professional, which may contribute to the issues faced during the hiring process. In fact, most individuals require extensive post-hire training before they can begin normal operations. The goal in cybersecurity is to become operationally resilient, which means in part that employees of an organization are trained to prevent and handle a cybersecurity incident. Therefore, the authors present a project that offers a solution to the education gap by creating a workforce pipeline for ICS cybersecurity professionals. The project is a virtual ecosystem for collaboration and transforming operational resilience (VECTOR). VECTOR incorporates many different efforts to increase operational resilience including the development of ICS cybersecurity curriculum and apprenticeships.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗