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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

DESIGNING A PARTICLE FLOW CONTROL APPARATUS

Flow control within a particle-based Concentrated Solar Power (CSP) system is essential in determining the heat transfer coefficient, and therefore, the power generation capability of these systems. There are three areas where particle flow control is significant: the receivers, storage tanks, and particle-sCO2 heat exchangers. The focus of this paper is on designing a new mechanism to control the flow in the particle-sCO2 heat exchangers due to the simplicity and potential cost savings when compared to the other areas of interest. The goal is for this new design to have quicker response times in terms of particle flowrate than a slide gate or flow control valve, which are designs currently used. The design resembles that of a chuck mechanism within a drill where a rotation of the sleeve elicits movement of the jaws both vertically and horizontally to close the outlet area of the nozzle. Additionally, this design will utilize the current actuator that is already used within these heat exchangers to reduce the complexity of implementation. The jaws are designed to be closed at an angle of 76 ̊ which is just slightly steeper than the hopper leading to the mechanism. Furthermore, this design can be tuned to limit particle bridging and other particle flow phenomena that result in blockages. The prototypes were 3D printed out of polylactic acid (PLA) and scaled up to 100%, 200%, and 400% to be able to observe the velocity profiles of the mechanism more clearly. Experiments are performed with this prototype to compare the inlet and outlet mass flow rates at different configurations of the jaws. The particles used in these experiments are 0.3mm HSP 40/70 that are commonly used in particle-based CSP systems.

14 SOLAR ENERGY↗
DOE OSTI2022

Deformation of Polycrystalline MgO Up to 8.3 GPa and 1270 K: Microstructures, Dominant Slip-Systems, and Transition to Grain Boundary Sliding

Ferropericlase is the second most abundant mineral in the Earth’s lower mantle and its mechanical properties have a strong influence on the rheology of this region. Here, we deform polycrystalline MgO, the magnesium end-member of ferropericlase, at conditions ranging from 1.6 to 8.3 GPa and 875–1,270 K. We analyse the flow laws and microstructures of the recovered samples using electron microscopy and compare our observations with predictions from the literature. We identify a first mechanism for samples deformed at 1,270 K, attributed to a regime controlled by grain boundary sliding accommodated by diffusion, and characterized by a small grain size, an absence of texture, and no intracrystalline deformation. At 1,070 K and below, the deformation regime is controlled by dislocations. The samples show a more homogeneous grain size distribution, significant texture, and intracrystalline strains. In this regime, deformation is controlled by the ⟨110⟩{110} slip system and a combined ⟨110⟩{110} and ⟨110⟩{100} slip, depending on pressure and temperature. Based on these results, we propose an updated deformation map for polycrystalline MgO at mantle conditions. The implications for ferropericlase and seismic observations in the Earth’s lower mantle are discussed.

Ledoux, Estelle Elisa↗
DOE OSTI2025

On optimal control of hybrid dynamical systems using complementarity constraints

Optimal control for switch-based dynamical systems is a challenging problem in the process control literature. In this study, we model these systems as hybrid dynamical systems with finite number of unknown switching points and reformulate them using non-smooth and non-convex complementarity constraints as a mathematical program with complementarity constraints (MPCC). We utilize a moving finite element based strategy to discretize the differential equation system to accurately locate the unknown switching points at the finite element boundary and achieve high-order accuracy at intermediate non-collocation points. We propose a globalization approach to solve the discretized MPCC problem using a mixed NLP/MILP-based strategy to converge to a non-spurious first-order optimal solution. The method is tested on three dynamic optimization examples, including a gas–liquid tank model and an optimal control problem with a sliding mode solution.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Utah FORGE 5-2419: Temperature Testing of Proppants for EGS and Stimulation of Electromagnetic Fracture Mapping Using Electrically-Conducive Proppants - 2024 Annual Workshop Presentation

This is a presentation on the Temperature Testing of Proppants for EGS and Stimulation of Electromagnetic Fracture Mapping Using Electrically-Conducive Proppants by Stevens Institute of Technology, presented by Cheng Chen. This video slide presentation discusses well controlled laboratory experiments testing the high-temperature performance of electrically-conductive and non-electrically-conductive proppants in maintaining fractures hydraulic and electrical conductivities to understand and quantify the thermal-hydrologic-mechanical-chemical mechanisms that regulate the observed behaviors. This will be tested using proppant/fracture imaging via borehole electromagnetic measurements. This presentation was featured in the Utah FORGE R&D Annual Workshop on August 15, 2024.

15 GEOTHERMAL ENERGY↗
DOE OSTI2026

Identifying Strain Stacking Boundaries between Multiphase Domains in Atomically Thin Two-Dimensional Magnets

Stacking engineering of van der Waals materials is an important strategy to control the materials’ properties, such as electronic correlations, ferroelectricity, and layer-dependent two-dimensional magnetism. A timely testbed for the study of the latter is atomically thin chromium trihalides (CrX 3 , X = Cl, Br, I). Notably, by understanding the sliding mechanism between different stacking sequences, control of the stacking arrangement, and thus magnetic properties in CrX 3 , can be achieved. Such insight, however, is currently lacking. Here, in this study, advanced electron microscopy methods are used to identify multiple stacking sequences corresponding to different bulk phases in atomically thin CrX 3 (X = Cl and Br) down to bilayer thickness and with lateral domain sizes as small as tens of nanometers. Indications of nanometer scale transitions and interactions at the stacking boundaries are found, including a universally preferred sliding direction that is consistent with density functional theory calculations and the strain fields at lateral heterostructure boundaries. This study demonstrates the necessity to consider local stacking structures when interpreting averaged magnetic properties measured with macroscale probes. Additionally, the preferred sliding direction insight from this study provides a strategy to control stacking sequence in atomically thin CrX 3 samples during the exfoliation and sample fabrication process.

DFT calculations↗
DOE OSTI2020

Berry curvature memory through electrically driven stacking transitions

In two-dimensional layered quantum materials, the interlayer stacking order determines both crystalline symmetry and quantum electronic properties such as Berry curvature, topology and electron correlation. Electrical stimuli can strongly influence quasi-particle interactions and the free energy landscape, thus making it possible to access hidden stacking orders with novel quantum properties and enabling dynamic engineering of these attributes. In this paper, we demonstrate electrically driven stacking transitions and a new type of nonvolatile memory based on Berry curvature in few-layer WTe 2 . The interplay of out-of-plane electric fields and electrostatic doping controls in-plane interlayer sliding and creates multiple polar and centrosymmetric stacking orders. In-situ nonlinear Hall transport reveals such stacking rearrangements result in a layer-parity-selective Berry curvature memory in momentum space, where the sign reversal of the Berry curvature only occurs in odd layer crystals. Our findings open an avenue towards exploring coupling between topology, electron correlations, and ferroelectricity in hidden stacking orders and demonstrate a new low energy cost, electrically-controlled topological memory in the atomically thin limit.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Long-Term Monitoring & Stewardship at Los Alamos National Laboratory [Slides]

Development and implementation of the Institutional Control Evaluation Project will include: Evaluate institutional surface water controls and infrastructure installed by LANL. Implement pilot project in the Los Alamos Canyon Watershed Spring, 2020. Initial evaluations will include canyon bottom controls with plan to expand program as funding allows. This will be a building block for successful Long-Term Monitoring and Stewardship (LTM&S) Program.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Design and Development of a Particle Flow Control Mechanism for Particle-Based CSP System Applications

Within particle-based Concentrated Solar Power Systems (CSP), particles are the heat transfer medium, and therefore, the heat transfer effectiveness of these systems is reliant on their ability to effectively control particle mass flow rate. The vast majority of approaches for particle flow control in high temperature CSP is based on a slide-gate approach where a gate is linearly actuated across a tear-drop shaped opening. The slide-gate mechanism has a sensitivity of 0.354 g/s-mm, which is defined as the mass flow rate over the position of the gate. In the present work, we have designed and tested a new particle flow control mechanism with the potential for faster response times and different sensitivities than a slide gate approach enabling more control of particle flow. The new device enables flow control through moving jaws diagonally to change the outlet area. The new devices sensitivity value follows a quadratic curved as compared to the slide-gate’s linear slope over the same jaw movement. A larger sensitivity value is directly related to a quicker response time when utilizing the same actuator.

14 SOLAR ENERGY↗
DOE OSTI2025

Linear Reciprocating Tribometer for In Situ Neutron Reflectometry of Soft Matter

Neutron reflectometry is a technique for measuring structure near planar interfaces that has been previously used to non-destructively characterize the polymer density of hydrated, dilute, and soft materials. Previous investigations have conducted neutron reflectometry measurements of liquids, gels, emulsion, and polymer solutions at rest, in compression, and subject to shear stress. However, correlating structure with tribological properties of soft materials presents significant experimental challenges for prior instruments due to wall slip, sample thickness, and structural heterogeneity (e.g., depth-wise gradients). A linear reciprocating tribometer offers several advantages for in situ neutron reflectometry studies, including uniform velocity profiles, constant shear stress over large regions of interest, and independent control of normal force and sliding velocity during measurements. This work outlines basic considerations for the design of a custom linear reciprocating tribometer that operates in a neutron beamline and includes commissioning measurements. The tribometer is designed to compress soft and hydrated materials against linearly reciprocating silicon disks. The three key design considerations for this tribometer are (1) safety, (2) neutron transmission, and (3) sample positioning. This instrument design will enable in situ studies of soft matter and illuminate the role of interfacial structure on tribological phenomena.

42 ENGINEERING↗
DOE OSTI2023

Design and Development of a Particle Flow Control Mechanism for Particle-Based CSP System Applications

The submission is a two-page extended abstract. Within particle-based Concentrated Solar Power Systems (CSP), particles are the heat transfer medium, and therefore, the heat transfer effectiveness of these systems is reliant on their ability to effectively control particle mass flow rate. The vast majority of approaches for particle flow control in high temperature CSP is based on a slide-gate approach where a gate is linearly actuated across a tear-drop shaped opening. The slide-gate mechanism has a sensitivity of 0.354 g/s-mm, which is defined as the mass flow rate over the position of the gate. In the present work, we have designed and tested a new particle flow control mechanism with the potential for faster response times and different sensitivities than a slide gate approach enabling more control of particle flow.

14 SOLAR ENERGY↗
DOE OSTI2024

Frictional Heating Measurements in PBX 9501

Heating due to frictional processes is one of many proposed mechanisms for hot spot ignition in explosives during sub-shock, mechanical loading. Novel experiments were conducted to isolate this mechanism and measure the temperature rise due to frictional heating in PBX 9501. A rheometer was used to apply mechanical sliding loads at the interface between two explosive pellets with a controlled axial load, and the resulting coefficient of friction of the material sliding against itself and te

Brown, Judith Alice↗
DOE OSTI2026

Evaluating lightweight unsupervised online IDS for masquerade attacks in CAN

Vehicular controller area networks (CANs) are susceptible to masquerade attacks by malicious adversaries. In masquerade attacks, adversaries silence a targeted ID and then send malicious frames with forged content at the expected timing of benign frames. As masquerade attacks could seriously harm vehicle functionality and are the stealthiest attacks to detect in CAN, recent work has devoted attention to compare frameworks for detecting masquerade attacks in CAN. However, most existing works report offline evaluations using CAN logs already collected using simulations that do not comply with the domain’s real-time constraints. Here we contribute to advance the state of the art by presenting a comparative evaluation of four different non-deep learning (DL)-based unsupervised online intrusion detection systems (IDS) for masquerade attacks in CAN. Our approach differs from existing comparative evaluations in that we analyze the effect of controlling streaming data conditions in a sliding window setting. In doing so, we use realistic masquerade attacks being replayed from the ROAD dataset. We show that although evaluated IDS are not effective at detecting every attack type, the method that relies on detecting changes in the hierarchical structure of clusters of time series produces the best results at the expense of higher computational overhead. We discuss limitations, open challenges, and how the evaluated methods can be used for practical unsupervised online CAN IDS for masquerade attacks.

Anomaly detection↗
DOE OSTI2026

Aluminum 4047 Vendor Review [Slides]

The selected filler wire manufacturer should have full control of the filler wire manufacturing process (i.e. ingot metal, green rod, filler wire manufacturing and packaging). LANL would like to purchase filler wire as an off-the-shelf product in small quantities over time to maintain a fresh stock and eliminate issues related to long-term storage of aluminum. The filler wire would be purchased in 0.047” dia. on small (ideally 5 lb.) spools, but no larger than 16 lbs.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Environmental Impact of Capture Technology A Review of DOE-Sponsored FEED Studies

The slides were presented at the USEA and FECM organized “Workshop on Measurement, Monitoring and Controlling Potential Environmental Impacts from the Installation of Point Source Capture”. The slides discuss insight regarding the environmental impact of capture system implementation gained from reviewing public FEED reports completed under FOA 2058. The slides were edited to add language requested by DOE and will published on the workshop website.

Homsy, Sally↗