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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Energy-resolved neutron imaging and diffraction including grain orientation mapping using event camera technology

Time-of-flight neutron diffraction and energy-resolved imaging each provide unique perspectives into material properties. Neutron diffraction is useful for assessing microstructural parameters such as phase composition, texture, and dislocation densities, though it typically provides averaged data over the sampled volume. Energy-resolved imaging, on the other hand, offers both spatial and spectral information by detecting Bragg edges and neutron absorption resonances, which enables detailed mapping of microstructure and isotopic composition. When combined, these techniques have the potential to enrich our understanding of material behavior across different scales, enhancing our understanding of complex materials. Traditionally, these modalities are conducted on separate instruments, which is time-consuming and poses challenges for data integration. Here, we report the integration of the LumaCam, an event-mode energy-resolved neutron imaging camera with the HIPPO time-of-flight diffractometer at LANSCE. This integration enables simultaneous diffraction and imaging across the full spectrum, with analysis optimized for diffraction and Bragg-edge imaging in the thermal range (0.45–10 Å) and resonance imaging in the epithermal range (0.5–3000 eV), facilitating comprehensive multi-modal analysis. We demonstrate its capabilities through case studies, including spatial mapping of grain orientations in a steel sample and accurate thickness estimations for irregular samples including a depleted uranium cylinder and a natural silver-containing mineral specimen. The combined setup enhances real-time sample alignment and provides comprehensive data for crystal structure, texture, and isotopic composition analysis. This approach opens new possibilities for advanced applications in nuclear engineering, archaeology, and materials science.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Evolution of intermittent filaments in the scrape-off layer of NSTX

Filamentary structures naturally arise from background turbulence in the scrape-off layer (SOL) of plasmas, leading to significant particle and heat transport that can degrade overall plasma confinement. This enhanced transport can contribute to unacceptably high heat loads on plasma-facing components. As such, understanding the physics of SOL plasma filaments is critical for predicting and mitigating their effects in future fusion devices. On the National Spherical Torus Experiment (NSTX), plasma filaments—commonly referred to as “blobs”—were investigated using the gas-puff imaging (GPI) diagnostic in the edge and SOL regions. The analysis involved identifying, segmenting, and tracking the characteristic contours of the blobs in each frame of the GPI video sequences. Their evolution was characterized through shape descriptors, velocity, and angular velocity derived from their contour coordinates. The results indicate that as the blob area increases, their shapes become more concave and less circular, suggesting reduced structural stability in larger blobs. This result aligns with previous theoretical results where it was shown that larger blobs are more susceptible to instabilities [Krasheninnikov et al., J. Plasma Phys. 74, 679–717 (2008) and D'Ippolito et al., Phys. Plasmas 18, 060501 (2011)]. A positive correlation was observed between radial velocity and radial position, suggesting radially outward acceleration of the filaments, potentially driven by decreasing viscous drag toward the far SOL. Interestingly, blobs in background SOL turbulence exhibited minimal spinning in contrast to filaments originating from edge localized modes, which show substantial rotation during their paths [Lampert et al., Phys. Plasmas 29, 102502 (2022)]. Statistical analysis of the solidity and total curvature shape descriptors, along with their temporal evolution, revealed relatively broad, near-Gaussian distributions. This suggests that blob morphology is strongly influenced by stochastic turbulent processes in the surrounding plasma environment. Blob parameters were also compared with bulk plasma and radial profile measurements. Notable trends were found between blob rotation and poloidal velocity with collisionality and line-integrated density. These findings contribute to a deeper understanding of blob dynamics and provide valuable insights for refining SOL turbulence models.

Covariance and correlation↗
DOE OSTI2026

Engineering diamond interfaces free of dark spins

Nitrogen-vacancy (NV) centers in diamond are utilized extensively as quantum sensors for imaging fields at the nanoscale. The ultrahigh sensitivity of NV magnetometers has enabled the detection and spectroscopy of individual electron spins, with potentially far-reaching applications in condensed matter physics, spintronics, and molecular biology. However, the surfaces of these diamond sensors naturally contain electron spins, which create a background signal that can be hard to differentiate from the signal of the target spins. In this study, we develop a surface modification approach that eliminates the unwanted signal of these so-called dark electron spins. Our surface passivation technique, based on coating diamond surfaces with a thin titanium oxide (Ti⁢O 2 ) layer, reduces the dark spin density. The observed reduction in dark spin density aligns with our findings on the electronic structure of the diamond-Ti⁢O 2 interface. The reduction, from a typical value of 2000 μm −2 to a value below that set by the detection limit of our NV sensors (200 μm −2 ), results in a twofold increase in Hahn-echo coherence time of near surface NV centers. Furthermore, we derive a comprehensive spin model that connects dark spin relaxation with NV coherence, providing additional insights into the mechanisms behind the observed spin dynamics. Our findings are directly transferable to other quantum platforms, including nanoscale solid-state qubits and superconducting qubits.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2024

Development of a self-lubricating high-efficiency hybrid seal composed of carbon nanotube-coated metal meshes for CSP turbomachinery (SETO CPS #36333 Final Report)

In turbomachinery, internal leakage flow accounts for up to 3% of the total thermodynamic cycle energy loss. Tradeoff must be made between the sealing efficiency (smaller clearance) and the friction and wear issues for interfering with the shaft (larger clearance). This ORNL-Danfoss joint effort developed a novel hybrid seal composed of carbon nanotube (CNT)-coated metal meshes. The CNT growth process was based on a self-catalyzing chemical vapor deposition and these multiwall CNTs were well aligned with high crystallinity. This hybrid material structure takes advantage of the CNT’s low-friction nature and uses the metal mesh as an extendable backbone. Full-scale experimental seals were designed, fabricated, and optimized for sealing performance and durability. The CNT-coated metal mesh seal demonstrated superior gas sealing efficiency to the baseline labyrinth seal and significantly improved shaft surface protection compared with the state-of-the-art superalloy brush seal on the static rig and full-scale compressor dynamometer tests. The CNT-metal mesh seal is low-cost and scalable and can potentially benefit wide applications, including CSP and other power generation, marine, automotive, and HVAC.

36 MATERIALS SCIENCE↗
DOE OSTI2026

The Evolving Role of Demand Charges in Retail Electricity Rates

Retail electricity demand charges refer to a type of retail rate that is based on a metric of kilowatt (kW) demand rather than kilowatt-hour (kWh) energy usage. Demand charges are widely used in the commercial and industrial (C&I) electricity sectors to recover significant portions of utility revenue and are also used in residential rates in a modest but growing number of locations. This paper explores the historical context of and motivations for demand charges, describes their implementation and impacts in today's context, and uses a variety of opinions collected from relevant parties through semi-structured interviews to inform how demand charges align with four widely accepted rate design principles. This project is funded by the Department of Energy's Office of Electricity, which is interested in conducting research to understand the current state of affairs related to demand charges and how the future U.S. electricity grid will help to define retail rates.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1975

Single radial magnetic bearing: A concept

Proposed bearing has increased stability. Magnetic structure keeps inner and outer bearing halves aligned. Electronic feedback circuit keeps bearing radially centered.

Studer, P. A.↗
NASA NTRS1978

Interplanetary magnetic holes: Theory

Magnetic holes in the interplanetary medium are explained as stationary, non-propagating, equilibrium structures in which there are field-aligned enhancements of the plasma density and/or temperature. Magnetic anti-holes are considered to be associated with depressions in the plasma pressure. In this model, the observed changes in the magnetic field intensity and direction are due to diamagnetic currents that are carried by ions which drift in a sheath as the result of gradients in the magnetic field and in the plasma pressure within the sheath. The thickness of the sheaths considered is approximately a few ion Larmor radii. An electric field is normal to the magnetic field in the sheath. Solutions of Vlasov's equation and Maxwell's equations are presented which account for several types of magnetic holes, including null-sheets, that were observed.

Burlaga, L. F.↗
NASA NTRS1978

Interplanetary magnetic holes - Theory

Magnetic holes in the interplanetary medium are explained as stationary nonpropagating equilibrium structures in which there are field-aligned enhancements of the plasma density and/or temperature. Magnetic antiholes are considered to be associated with depressions in the plasma pressure. In this model the observed changes in the magnetic field intensity and direction are due to diamagnetic currents that are carried by ions which drift in a sheath as the result of gradients in the magnetic field and in the plasma pressure within the sheath. The thickness of the sheaths that we consider is approximately a few ion Larmor radii. An electric field is normal to the magnetic field in the sheath. Solutions of Vlasov's equation and Maxwell's equations are presented which account for several types of magnetic holes, including 'null sheets,' that have been observed.

Burlaga, L. F.↗
NASA NTRS1989

The use of curvilinear fiber format in composite structure design

This paper investigates the gains in structural efficiency that can be achieved by aligning the fibers in some or all of the layers in a laminate with the principal stress directions in those layers. The name curvilinear fiber format is given to this idea. The problem studied is a plate with a central circular hole subjected to a uniaxial tensile load. An iteration scheme is used to find the fiber directions at each point in the laminate. Two failure criteria are used to evaluate the tensile load capacity of the plates with a curvilinear format, and for comparison, counterpart plates with a conventional straightline fiber format. The curvilinear designs for improved tensile capacity are then checked for buckling resistance. It is concluded that gains in efficiency can be realized with the curvilinear format.

Hyer, M. W.↗
NASA NTRS2001

Metallic Electrode: Semiconducting Nanotube Junction Model

A model is proposed for two observed current-voltage (I-V) patterns in an experiment with a scanning tunneling microscope tip and a carbon nanotube [Collins et al., Science 278, 100 ('97)]. We claim that there are two contact modes for a tip (metal) -nanotube semi conductor) junction depending whether the alignment of the metal and semiconductor band structure is (1) variable (vacuum-gap) or (2) fixed (touching) with V. With the tip grounded, the tunneling case in (1) would produce large dI/dV with V > 0, small dI/dV with V < 0, and I = 0 near V = 0 for an either n- or p-nanotube. However, the Schottky mechanism in (2) would result in forward current with V < 0 for an n-nanotube, while with V > 0 for an p-nanotube. The two observed I-V patterns are thus entirely explained by a tip-nanotube contact of the two types, where the nanotube must be n-type. We apply this picture to the source-drain I-V characteristics in a long nanotube-channel field-effect-transistor (Zhou et al., Appl. Phys. Lett. 76, 1597 ('00)], and show that two independent metal-semiconductor junctions connected in series are responsible for the observed behavior.

Yamada, Toshishige↗
NASA NTRS2004

Spirit at Gusev Crater: Preliminary Observations, Potential Processes and Hypotheses

Spirit landed in a flat plain in Gusev crater with local undulations at meters scales generated by ridges covered with blocks, some of them looking rounded. Several, flat-topped, mesas are visible in the far field in direction of Ma adim Vallis. A set of north/south oriented hills reaches approximately 150 m elevation to the east of the landing site (LS). A dipping brighter unit with possibly some scarps is associated with it. This setting could be consistent with layering observed on the MOC images of the hills, local exposure of material with variable dust cover, or deflated or allochtonous material. Numerous small depressions are visible from LS referred to as "Columbia Memorial Station"* (CMS). Floors are partially filled with finer-grained, high albedo material. At least one of them, nicknamed "Sleepy Hollow"* (approximately 30 m diameter) may be an eroded secondary impact crater. It is unclear if they can all be related to small impact structures. Some of them are elongated and aligned with the ridges. The morphology of rocks and soil at this Gusev Crater is presented. Evidence of dynamic aeolian action along this Crater is also discussed.

Cabrol, N. A.↗
NASA NTRS2005

Conceptual Design and Dynamics Testing and Modeling of a Mars Tumbleweed Rover

The NASA Langley Research Center has been developing a novel concept for a Mars planetary rover called the Mars Tumbleweed. This concept utilizes the wind to propel the rover along the Mars surface, bringing it the potential to cover vast distances not possible with current Mars rover technology. This vehicle, in its deployed configuration, must be large and lightweight to provide the ratio of drag force to rolling resistance necessary to initiate motion from rest on the Mars surface. One Tumbleweed design concept that satisfies these considerations is called the Eggbeater-Dandelion. This paper describes the basic design considerations and a proposed dynamics model of the concept for use in simulation studies. It includes a summary of rolling/bouncing dynamics tests that used videogrammetry to better understand, characterize, and validate the dynamics model assumptions, especially the effective rolling resistance in bouncing/rolling dynamic conditions. The dynamics test used cameras to capture the motion of 32 targets affixed to a test article s outer structure. Proper placement of the cameras and alignment of their respective fields of view provided adequate image resolution of multiple targets along the trajectory as the test article proceeded down the ramp. Image processing of the frames from multiple cameras was used to determine the target positions. Position data from a set of these test runs was compared with results of a three dimensional, flexible dynamics model. Model input parameters were adjusted to match the test data for runs conducted. This process presented herein provided the means to characterize the dynamics and validate the simulation of the Eggbeater-Dandelion concept. The simulation model was used to demonstrate full scale Tumbleweed motion from a stationary condition on a flat-sloped terrain using representative Mars environment parameters.

Calhoun Philip C.↗
NASA NTRS1959

Welded Titanium Case for Space-Probe Rocket Motor

Early in 1958, the Jet Propulsion Laboratory of the California Institute of Technology was requested to participate in a lunar-probe mission code-named Juno II which would place a 15-lb Instrumented payload (Pioneer IV) in the vicinity of the moon. The vehicle was to use the same high-speed upper-stage assembly as flown on the successful Jupiter-C configuration; however, the first-stage booster was to be a Jupiter rather than a Redstone. An analysis of the intended flight and payload configuration Indicated that the feasibility of accomplishing the mission was questionable and that additional performance would have to be obtained if the mission was to be feasible. Since the most efficient way of Increasing the performance of a staged vehicle is to increase the performance of the last stage, a study of possible ways of doing this was made.. Because of the time schedule placed on this effort It was decided to reduce the weight of the fourth-stage rocket-motor case by substituting the annealed 6Al--4V titanium alloy for the Type 410 stainless steel. Although this introduced an unfamiliar material, It reduced the changes in design and fabrication techniques. This particular titanium alloy was chosen on the basis of previous tests which proved the suitability of the alloy as a pressure-vessel material when used at an annealed yield strength of about 120, 000 psi. The titanium-case fourth stage of Juno U is shown with the payload and on the missile in Fig. 1; the stainless-steel motor cases used in the Jupiter-C vehicle are shown in Fig. 2. The fourth-stage motor case has a diameter of 6 in., a length of approximately 38 in. center dot and a nominal cylindrical wall thickness of 0.025 in. As shown in Fig. 1, the case serves as the structural support of the payload and is aligned to the upper stage assembly through an alignment ring. The nozzle is threaded into the end of the motor case, and is of the ceramic-coated steel design. Figure 3 shows a comparison of the components used to make the stainless steel and the 6A1--4V titanium alloy cases. The forward dome and aft fitting for the stainless steel assembly were fabricated from a combination of forged, spun and machined parts.. In order to facilitate the fabrication of the titanium alloy motor ) these components were machined from a large-diameter billet.

Brothers, A. J.↗
NASA NTRSDate not supplied

Polarized Observations of Falling Snow from IMPACTS

The polarization of electromagnetic waves (radio waves and light) provides useful information on the dynamics and structure of precipitating storms. Polarization results from aligned precipitation particles interacting with the electromagnetic waves. This orientation is related to the dynamics of the weather system, and the orientation effects the radiative properties of the clouds (which is related to climate sensivity and feedbacks). We use observations from the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Storms (IMPACTS), a NASA field campaign aiming to understand winter storms that regularly impact the East Coast of the United States, to understand the relationship between properties of snowstorms and polarization of millimeter waves (89 GHz and 166 GHz). We see that height and intensity are strong indicators of the polarization signatures observed in these systems.

Ian S Adams↗
DOE OSTI2021

Cartridge systems, capacitive pumps and multi-throw valves and pump-valve systems and applications of same

The invention relates to a cartridge of a fluidic device. The fluidic device includes a fluidic chip, a body having a first surface and an opposite, second surface, one or more channels formed in the body in fluidic communications with input ports and output ports for transferring one or more fluids between the input ports and the output ports, and a fluidic chip registration means formed on the first surface for aligning the fluidic chip with a support structure; and an actuator configured to engage with the one or more channels at the second surface of the body for selectively and individually transferring the one or more fluids through the one or more channels from at least one of the input ports to at least one of the output ports at desired flowrates.

Schaffer, David K.↗
DOE OSTI2022

Cartridge systems, capacitive pumps and multi-throw valves and pump-valve systems and applications of same

In one aspect of the invention, the fluidic device includes a fluidic chip includes a body having a first surface and an opposite, second surface, one or more channels formed in the body in fluidic communications with input ports and output ports for transferring one or more fluids between the input ports and the output ports, and a fluidic chip registration means formed on the first surface for aligning the fluidic chip with a support structure; and an actuator configured to engage with the one or more channels at the second surface of the body for selectively and individually transferring the one or more fluids through the one or more channels from at least one of the input ports to at least one of the output ports at desired flowrates.

Schaffer, David K.↗
DOE OSTI2022

Methods and apparatus to facilitate alkali metal transport during battery cycling, and batteries incorporating same

An anode includes a mixed ionic-electronic conductor (MIEC) with an open pore structure. The open pore structure includes open pores to facilitate motion of an alkali metal into and/or out of the MIEC. The open pore structure thus provides open space to relieve the stresses generated by the alkali metal when charging/discharging a battery. The MIEC is formed from a material that is thermodynamically and electrochemically stable against the alkali metal to prevent the formation of solid-electrolyte interphase (SEI) debris and the formation of dead alkali metal. The MIEC may also be passive (the MIEC does not store or release alkali metal). In one example, the open pore structure may be an array of substantially aligned tubules with a width less than about 300 nm, a wall thickness between about 1 nm to about 30 nm, and a height of at least 10 um arranged as a honeycomb.

Li, Ju↗
NASA NTRS1979

Homogeneous alignment of nematic liquid crystals by ion beam etched surfaces

A wide range of the ion beam etch parameters are capable of producing uniform homogeneous alignment of nematic liquid crystals on SiO2 films. The alignment surfaces were generated by obliquely incident argon ions; a smaller range of ion beam parameters was also investigated with ZrO2 films and found suitable for homogeneous alignment. Extinction ratios were very high, and twist and tilt-bias angles were very small. The SEM results indicate a parallel oriented surface structure on the ion beam etched surfaces which may determine alignment.

Wintucky, E. G.↗