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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

Distributed Embedded Energy Converters for Ocean Wave Energy Harvesting: Enabling a Domain of Transformative Technologies: Preprint

Distributed embedded energy conversion technology (DEEC-Tec) is a very promising - but underdeveloped - domain in marine renewable energy research. The technology utilizes small distributed embedded energy converters (DEECs) that, in aggregate, form a much larger energy harvesting-converting structure. Each DEEC is a small transducer - an individual mechanism that converts one form of energy into another. A transducer's specific mode of operation can be based upon any number of physical phenomena, including variable capacitance, variable magnetic fields, or piezoelectrics. It is the dynamic deformation of a structure made from such DEECs (a DEEC-Tec structure) that provides the needed physical phenomena (the external energy source) for the underlying transducers to intake and convert energy into another form, such as electricity. DEEC-Tec structures designed specifically to dynamically deform in the presence of ocean wave energy - for the purpose of harvesting and converting that energy - can be called flexWECs. A flexWEC's gross shape (topology) and its compliant characteristics (morphologies) are chiefly determined by how the DEECs making up its structure are arranged and implemented. In turn, those corresponding topologies and morphologies will largely determine how a flexWEC interacts with - and dynamically deforms within - the presence of ocean wave energy. FlexWECs appear to have many attractive features, including broad-banded ocean energy conversion, in situ energy conversion throughout an entire flexWEC structure, inherent redundancy, and appealing material and manufacturing costs. To this end, the design and development of any particular flexWEC or flexWEC feature is a revolutionary opportunity for how we conceptualize and envision the future of ocean wave energy conversion.

50 EE - Wind and Water Power Program - Water (EE-4↗
DOE OSTI2021

Distributed Embedded Energy Converters for Ocean Wave Energy Harvesting: Enabling a Domain of Transformative Flexible Technologies

Distributed embedded energy conversion technology (DEEC-Tec) is a very promising - but underdeveloped - domain in marine renewable energy research. The technology utilizes small distributed embedded energy converters (DEECs) that, in aggregate, form a much larger energy harvesting-converting structure. Each DEEC is a small transducer - an individual mechanism that converts one form of energy into another. A transducer's specific mode of operation can be based upon any number of physical phenomena, including variable capacitance, variable magnetic fields, or piezoelectrics. It is the dynamic deformation of a structure made from such DEECs (a DEEC-Tec structure) that provides the needed physical phenomena (the external energy source) for the underlying transducers to intake and convert energy into another form, such as electricity. DEEC-Tec structures designed specifically to dynamically deform in the presence of ocean wave energy - for the purpose of harvesting and converting that energy - can be called flexWECs. A flexWEC's gross shape (topology) and its compliant characteristics (morphologies) are chiefly determined by how the DEECs making up its structure are arranged and implemented. In turn, those corresponding topologies and morphologies will largely determine how a flexWEC interacts with - and dynamically deforms within - the presence of ocean wave energy. FlexWECs appear to have many attractive features, including broad-banded ocean energy conversion, in situ energy conversion throughout an entire flexWEC structure, inherent redundancy, and appealing material and manufacturing costs. To this end, the design and development of any particular flexWEC or flexWEC feature is a revolutionary opportunity for how we conceptualize and envision the future of ocean wave energy conversion.

DEEC↗
DOE OSTI2025

Crystallographic Evidence of Size-Dependent Bond Flexibility in Metal–Organic Framework Nanocrystals

Size-dependent electronic, magnetic, and optical behavior suggests that metal–organic frameworks become softer materials as their particle sizes decrease, but direct evidence is lacking. Here, we report variable-temperature powder X-ray diffraction data of Fe(1,2,3-triazolate)2 particles that offer crystallographic insight into size-dependent bond flexibility. Rietveld refinement reveals size-dependent positive thermal expansion upon downsizing the crystalline domains from 178 to 9 nm, with a 6-fold increase from 16 MK –1 to 96 MK –1 . Here, this behavior occurs in tandem with size-dependent elongation of metal–ligand bonds and increasing thermal displacement parameters, consistent with pronounced metal-linker bond lability. We propose that these effects, as well as size-dependent annealing of crystallite sizes, originate from the high charge density and surface stress of smaller particles. Taken together, these results provide structural evidence that size reduction serves as a synthetic route to controlling the dynamic response of materials to external stimuli.

Crystals↗
NASA NTRS1995

Multiwavelength monitoring of the BL Lacertae object PKS 2155-304. 3: Ground-based observations in 1991 November

We present ground-based observations of the BL Lac object PKS 2155-304 during 1991 November. These data were obtained as part of a large international campaign of observations spanning the electro-magnetic spectrum from the radio waves to the X-rays. The data presented here include radio and UBVRI fluxes, as well as optical polarimetry. The U to I data show the same behavior in all bands and that only upper limits to any lag can be deduced from the cross-correlation of the light curves. The spectral slope in the U-I domain remained constant on all epochs but 2. There is no correlation between changes in the spectral slope and large variations in the total or polarized flux. The radio flux variations did not follow the same pattern of variability as the optical and infrared fluxes. The polarized flux varied by a larger factor than the total flux. The variations of the polarized flux are poorly correlated with those of the total flux in the optical (and hence UV domain; see the accompanying paper by Edelson et al.) nor with those of the soft X-rays. We conclude that the variability of PKS 2155-304 in the optical and near-infrared spectral domains are easier to understand in the context of variable geometry or bulk Lorentz factor than of variable electron acceleration and cooling rates.

Courvoisier, T. J.-L.↗
DOE OSTI2023

Self-Assembly of Atomically Aligned Nanoparticle Superlattices from Pt–Fe 3 O 4 Heterodimer Nanoparticles

Multicomponent nanoparticle superlattices (SLs) promise the integration of nanoparticles (NPs) with remarkable electronic, magnetic, and optical properties into a single structure. Here, we demonstrate that heterodimers consisting of two conjoined NPs can self-assemble into novel multicomponent SLs with a high degree of alignment between the atomic lattices of individual NPs, which has been theorized to lead to a wide variety of remarkable properties. Specifically, by using simulations and experiments, we show that heterodimers composed of larger Fe 3 O 4 domains decorated with a Pt domain at one vertex can self-assemble into an SL with long-range atomic alignment between the Fe 3 O 4 domains of different NPs across the SL. The SLs show an unanticipated decreased coercivity relative to nonassembled NPs. In situ scattering of the self-assembly reveals a two-stage mechanism of self-assembly: translational ordering between NPs develops before atomic alignment. Here our experiments and simulation indicate that atomic alignment requires selective epitaxial growth of the smaller domain during heterodimer synthesis and specific size ratios of the heterodimer domains as opposed to specific chemical composition. This composition independence makes the self-assembly principles elucidated here applicable to the future preparation of multicomponent materials with fine structural control.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

Measurements of plasma parameters in the divertor island of Wendelstein 7-X through line-ratio spectroscopy on helium

We report electron temperature T e and density n e have been measured in the divertor island of Wendelstein 7-X by means of a new thermal He-beam system utilizing line-ratio spectroscopy. This system is equipped with a poloidal arrangement of five gas valves that allows to infer 2D plasma profiles T e ( R,Z ) and n e ( R,Z ) across the magnetic island forming the island divertor. A local maximum in T e ( R,Z ) was measured along the flux surfaces located between the island center and the outer separatrix. In the island center, characterized by closed field lines, a clear local minimum in T e was measured, indicating that no direct heat deposition occurs in this region and that the perpendicular heat flux from the core plasma into this domain is small. Increasing the island size leads to a reduction of the connection length in the scrape-off layer (SOL) and to a shift of the island center towards the divertor target. In this scenario, the T e ( R,Z ) are reduced in the entire island domain. Density profiles are found flat across the divertor island for both island size scenarios. These findings are supported by similar observations made with a reciprocating probe plunging through the same SOL island at the mid-plane of W7-X representing the upstream position in this 3D divertor geometry.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Unusual 5f magnetism in new kagome material UV 6 Sn 6

Materials in the family R V 6 Sn 6 (R = rare earth) provide a unique platform to investigate the interplay between local moments from R layers and nonmagnetic vanadium kagome layers. Yet, the investigation of actinide members remains scarce. Here we report the synthesis of UV 6 Sn 6 single crystals through the self-flux technique. Physical property measurements reveal two uranium-driven antiferromagnetic transitions at T N 1 = 29 K and T N 2 = 24 K, a complex field-temperature phase diagram, and unusual negative domain-wall magnetoresistance. Specific heat and angle-resolved photoemission spectroscopy measurements show a moderate f -electron enhancement to the density of states at the Fermi level (EF), whereas our band structure calculations place the vanadium flat bands 0.25 eV above E F . These findings point to a materials opportunity to expand the uranium 166 family with the goal of enhancing correlations by tuning 5 f and 3 d flat bands to E F .

36 MATERIALS SCIENCE↗
DOE OSTI2020

Instantons in chiral magnets

In this work, we exhaustively construct instanton solutions and elucidate their properties in one-dimensional antiferromagnetic chiral magnets based on the $\textit{O}(3)$ nonlinear sigma model description of spin chains with the Dzyaloshinskii-Moriya (DM) interaction. By introducing an easy-axis potential and a staggered magnetic field, we obtain a phase diagram consisting of ground-state phases with two points (or one point) in the easy-axis dominant cases, a helical modulation at a fixed latitude of the sphere, and a tricritical point allowing helical modulations at an arbitrary latitude. We find that instantons (or skyrmions in two-dimensional Euclidean space) appear as composite solitons in different fashions in these phases: temporal domain walls or wall-antiwall pairs (bions) in the easy-axis dominant cases, dislocations (or phase slips called merons) with fractional instanton numbers in the helical state, and isolated instantons and calorons living on the top of the helical modulation at the tricritical point. We also show that the models with DM interaction and an easy-plane potential can be mapped into those without them, providing a useful tool to investigate the model with the DM interaction.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS2012

Single Pixel Characterization of X-Ray TES Microcalorimeter Under AC Bias at MHz Frequencies

In this paper we present the progress made at SRON in the read-out of GSFC x-ray transition-edge sensor (TES) micro-calorimeters in the frequency domain. The experiments reported so far, whose aim was to demonstrate an energy resolution of 2eV at 6 keV with a TES acting as a modulator, were carried out at frequencies below 700 kHz using a standard flux locked loop (FLL) SQUID read-out scheme. The TES read-out suffered from the use of sub-optimal circuit components, large parasitic inductances, low quality factor resonators and poor magnetic field shielding. We have developed a novel experimental set-up, which allows us to test several read-out schemes in a single cryogenic run. In this set-up, the TES pixels are coupled via superconducting transformers to 18 high-Q lithographic LC filters with resonant frequencies ranging between 2 and 5 MHz. The signal is amplified by a two-stage SQUID current sensor and baseband feedback is used to overcome the limited SQUID dynamic range. We study the single pixel performance as a function of TES bias frequency, voltage and perpendicular magnetic field.

Gottardi, L.↗
NASA NTRS2012

PheniX: A New Vision for the Hard X-ray Sky

We are proposing a mission devoted to high energy X-ray astronomy that is based on a focusing telescope operating in the 1-200 keV energy range but optimized for the hard X-ray range. The main scientific topics concern: Physics of compact objects: The proximity of compact objects provides a unique laboratory to study matter and radiation in extreme conditions of temperature and density in strong gravitational environment. The emission of high energy photons from these objects is far from being understood. The unprecedented sensitivity in the high energy domain will allow a precise determination of the non-thermal processes at work in the vicinity of compact objects. The full 1-200 keV energy coverage will be ideal to disentangle the emission processes produced in the spacetime regions most affected by strong-gravity, as well as the physical links: disk-thermal emission-iron line-comptonisation-reflection-non-thermal emission-jets. Neutron stars-magnetic field-cyclotron lines: Time resolved spectroscopy (and polarimetry) at ultra-high sensitivity of AXP, milliseconds pulsars and magnetars will give new tools to study the role of the synchrotron processes at work in these objects. Cyclotron lines-direct measurement of magnetic filed-equation of state constraints-short bursts-giant flares could all be studied with great details. AGN: The large sensitivity improvement will provide detailed spectral properties of the high energy emission of AGN's. This will give a fresh look to the connection between accretion and jet emission and will provide a new understanding of the physical processes at work. Detection of high-redshift active nuclei in this energy range will allow to introduce an evolutionary aspect to high-energy studies of AGN, probing directly the origin of the Cosmic X-ray Background also in the non-thermal range (> 20 keV). Element formation-Supernovae: The energy resolution achievable for this mission (<0.5 keV) and a large high energy effective area are ideally suited for the 44Ti line study (68 and 78 keV). This radioactive nuclei emission will give an estimate of their quantities and speed in their environment. In addition the study of the spatial structure and spectral emission of SNR will advance our knowledge of the dynamics of supernovae explosions, of particles acceleration mechanisms and how the elements are released in the interstellar medium. Instrumental design: The progress of X-ray focusing optics techniques allows a major step in the instrumental design: the collecting area becomes independent of the detection area. This drastically reduces the instrumental background and will open a new era. The optics will be based on depth-graded multi-layer mirrors in a Wolter I configuration. To obtain a significant effective area in the hundred of keV range a focal length in the 40-50 meters range (attainable with a deployable mast) is needed. In addition such a mission could benefit from recent progress made on mirror coating. We propose to cover the 1-200 keV energy range with a single detector, a double-sided Germanium strip detector operating at 80 K. The main features will be: (a) good energy resolution (.150 keV at 5 keV and <.5 keV at 100 keV), (b) 3 dimensional event localization with a low number of electronic chains, (c) background rejection by the 3D localization, (d) polarisation capabilities in the Compton regime.

PHENIX↗
DOE OSTI2025

Coarsening dynamics of Ising-nematic order in a frustrated Heisenberg antiferromagnet

We study the phase ordering dynamics of the classical antiferromagnetic 𝐽 1 −𝐽 2 (nearest-neighbor and next-nearest-neighbor couplings) Heisenberg model on the square lattice in the strong frustration regime (𝐽 2 /𝐽 1 > 1/2). While thermal fluctuations preclude any long-range magnetic order at finite temperatures, the system exhibits a long-range spin-driven nematic phase at low temperatures. The transition into the nematic phase is further shown to belong to the two-dimensional Ising universality class based on the critical exponents near the phase transition. Our large-scale stochastic Landau-Lifshitz-Gilbert simulations find a two-stage phase ordering when the system is quenched from a high-temperature paramagnetic state into the nematic phase. In the early stage, collinear alignments of spins lead to a locally saturated Ising-nematic order. Once domains of well-defined Ising order are developed, the late-stage relaxation is dominated by curvature-driven domain coarsening, as described by the Allen-Cahn equation. The characteristic size of Ising-nematic domains scales as the square root of time, similar to the kinetic Ising model described by the time-dependent Ginzburg-Landau theory. Our results confirm that the late-stage ordering kinetics of the spin-driven nematic, which is a vestigial order of the frustrated Heisenberg model, belongs to the dynamical universality class of a nonconserved Ising order. Interestingly, the system shows no violation of the superuniversality hypothesis under weak bond disorder. The dynamic scaling invariance is preserved in the presence of weak bond disorder. Here, we also discuss possible applications of our results to materials for which vestigial Ising-nematic order is realized.

Antiferromagnets↗
DOE OSTI2019

Single- and Double-Layer Microwave Absorbers of Cobalt Ferrite and Graphite Composite at Gigahertz Frequency

Microwave absorbers of cobalt ferrite and graphite composite have been fabricated to investigate the broadening of absorption frequency by mixing small and large particles and comparing single- and double-layer composites in order to broaden the absorption frequency and to enhance multireflection and scattering of electromagnetic wave. CoO and Fe{sub 2}O{sub 3} precursors were mechanically alloyed and sintered at 800, 900, 1000 and 1100 {sup ∘}C in order to synthesise various particle sizes and shapes. A mixed sample of powders sintered at the above mentioned temperatures was also formed. The morphological, phase, and magnetic properties of these samples were studied. Two series of samples have been synthesised which were single- and double-layer composites. Single-layer composite consisted of mixed particles, and their thickness parameters were varied. Double-layer composite was also prepared with various particle sizes of CoFe{sub 2}O{sub 4} as a layer and graphene as another layer. The effect of these layers as matching and absorbing layer was studied. The degree of crystallinity of CoFe{sub 2}O{sub 4} was increased with increase of sintering temperature. Microstructural study showed the evolution of particle size and shape subjected to sintering temperature. Arrhenius plot showed two stages of growth process with activation energy calculated at 26.85 and 83.091 kJ/mol. The critical size of single domain of this sample plotted from the coercivity against particle size was 63.44 nm. Single-layer composite with mixed particle size was not able to show good electromagnetic (EM)-wave absorption; however double-layer composite showed good return loss. The mechanism of the EM-wave absorption of double-layer composite was discussed in this paper.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Thermal generation, manipulation and thermoelectric detection of skyrmions

The efficient generation, manipulation and detection of magnetic skyrmions are important for the development of future spintronic devices. One approach is to use electric-current-induced spin torques. Recently, thermally induced skyrmion motion has also been observed, but wider experimental evidence and its capabilities remain limited. Here we report the thermal generation, manipulation and thermoelectric detection of nanoscale skyrmions in microstructured metallic multilayers integrated with on-chip heaters. The local application of heat can facilitate a domain morphological transition and the formation of skyrmions at the device edge, where a low energy barrier exists. Here, we observe the unidirectional diffusion of skyrmions from hot regions to cold regions, which is due to the interplay among the repulsive forces between skyrmions, thermal spin–orbit torques, entropic forces and magnonic spin torques. The thermally generated skyrmions can also be electrically detected via the Nernst voltage.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Fluid dynamic simulation and analysis of water-cooling systems for the Electron-Ion Collider

The Electron-Ion Collider is the newest large-scale project at Brookhaven National Laboratory. The collider’s purpose is to provide further advancements in the knowledge of the universe’s origin by accelerating particles near the speed of light. Our project for this 3.8 km ring was to create a thermal hydraulic steady-state simulation design of the water-cooling system to be cost-effective and energy efficient, as envisioned by Charlie Foltz, the EIC Infrastructure Division Director. The system would include a supply and return header, which cools several thousand components of the ring. The water would then be returned and cooled down using a system of cooling towers and plate and frame heat exchangers. Due to the size of the system and the complexity of the network analysis, a fluid dynamic simulation software, AFT Fathom, was used. Since previous methods of maintaining systems relied on building upon smaller real-life models and implementing empirical data, this flow model was unique and first of a kind in the domain of accelerator design, construction and operation. Therefore, our hydraulic team piloted a new method to perform network analysis on a large scale cooling system. We successfully created several test scenarios for system behavior in a shorter time compared to the method of performing hand calculations. Cooling specifications for heat rejection, pressure drop, flow rate, and pipe sizing were changed based on the individual systems of the vacuum, radio frequency (RF), magnet and power supply, and cryogenics sections. Finally, we used DOE guidelines to perform life-cycle cost analysis with net present value and carbon saving analysis on the systems where pipe size could be optimized.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Structural Origins of High MoO 3 Solubility in Peraluminous Borosilicate Glasses

Molybdenum (Mo) imposes strict loading limits in conventional borosilicate nuclear waste glasses due to the tendency of tetrahedral molybdate [MoO 4 ] 2− species to phase-separate and crystallize as alkali molybdates. Here, we demonstrate an unprecedented 13.96 wt % (7.51 mol %) MoO 3 solubility in peraluminous sodium aluminoborosilicate glasses a ∼15× increase over their peralkaline counterparts. Using Raman spectroscopy, multinuclear and dipolarcorrelation magic angle spinning nuclear magnetic resonance (MAS NMR), electron paramagnetic resonance (EPR), and scanning transmission electron microscopy (STEM)-energy dispersive spectroscopy (EDS), we reveal that Nadeficient, low optical basicity conditions stabilize octahedral MoO 6 units, which polymerize into molybdite-like Mo−O clusters dispersed within the glass matrix. These Mo-rich clusters suppress the formation of depolymerized [MoO 4 ] 2− environments typically responsible for Na 2 MoO 4 precipitation and instead promote the formation of Na 2 Mo 2 O 7 as the saturation phase. Concurrently, Mo solubility drives the conversion of AlO 4 − to higher-coordination AlO 5 species, liberating Na + that is subsequently sequestered in molybdate-rich domains. The combined evolution of Mo coordination, modifier redistribution, and network depolymerization provides a mechanistic basis for the markedly enhanced Mo solubility in peraluminous compositions. These findings establish new structural guidelines for designing aluminoborosilicate waste forms with substantially greater capacity to incorporate Mo-rich nuclear waste streams.

Amorphous materials↗
DOE OSTI2018

Real Space Visualization of Competing Phases in La 0.6 Sr 2.4 Mn 2 O 7 Single Crystals

We report that correlated quantum materials are expected to provide the foundation for the next generation of information or energy technologies. A key feature of these materials is the proximity of multiple ground states close in energy, which results in the ability to tune properties with small changes in an external parameter such as magnetic field, composition, or temperature. For example, the colossal magnetoresistance exhibited by manganites is related to charge and orbital ordering and results from a metallic ferromagnetic phase in proximity to a paramagnetic insulating phase. The presence of competing ground states, at the heart of the physics and functionality of these materials, often results in nanoscale phase separation. Probing nanoscale phase separation with conventional diffraction techniques alone is not adequate, particularly when the domains are small or nanosized. In the present work we use a scanning transmission electron microscopy image-based technique of picometer precision strain maps (PPSM) to directly visualize the competing nanoscale phases with charge and orbital ordering in a double-layer manganite. Finally, this work underscores the role of subtle structural distortions in determining the electron physics in correlated quantum materials and provides insights into designing new functionalities via spatially tuning multiple competing ground states.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Dynamic Characteristics and Test Results of a Wave Power Take-off System with Mechanical Motion Rectification and Transmission

An innovative ocean wave power takeoff (PTO) system is presented here to enhance electrical energy generation from oscillating wave motions. This PTO system, mainly consisting of dual ball screws, gearbox with mechanical motion rectification (MMR) and a permanent magnet synchronous generator (PMSG), can convert bidirectional irregular motions from a floating wave buoy into unidirectional regular generator rotations. Systematical operating principles, design and prototyping details of the PTO system are presented and analyzed. A hydrodynamics-mechanical-electrical model of the system is established by reasonably representing power switches attached to the PMSG as an equivalent external resistance. The overall dynamics of the system are then analyzed in the frequency-domain. Three power control strategies are proposed to maximize the wave power absorption by changing the equivalent external resistance. The effectiveness and relatively high energy conversion efficiency of the PTO system have been demonstrated based on lab bench test results. The levelized cost of energy of a full scale wave energy converter system is also calculated based on the proposed PTO system.

16 TIDAL AND WAVE POWER↗