SEARCH · Search NASA

Results for “emergent property”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17

All sources NASA NTRS DOE OSTI

DOE OSTI2025

Dynamical dark energy from lattice quantum gravity

We study the behavior of the vacuum in Euclidean dynamical triangulations (EDT). Algorithmic improvements and better lattice spacing determinations allow us to test the properties of the emergent de Sitter geometries of our simulations to higher precision than previously possible. Although the agreement with de Sitter is good, the improved precision reveals deviations that can be interpreted as nontrivial vacuum dynamics, well described by a cosmological constant that runs with scale. The simulations show that the dominant running is quadratic and that the scale can be identified with the Hubble rate. Several key cross-checks support this picture, including consistent results across multiple lattice spacings and the fact that the null energy condition is not violated. The parameters of the running are fully determined by simulations, enabling predictions when extrapolated to the scales relevant for our Universe. This leads to a model for dark energy that is compatible with current observations, but which predicts deviations from the Standard Model of cosmology at the 𝒪⁡(10 −3 ) level in observables that could be tested with future improvements in precision measurements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

(Mg,Mn,Fe,Co,Ni)O: A rocksalt high-entropy oxide containing divalent Mn and Fe

High-entropy oxides (HEOs) have aroused growing interest due to fundamental questions relating to their structure formation, phase stability, and the interplay between configurational disorder and physical and chemical properties. Introducing Fe(ιι) and Mn(ιι) into a rocksalt HEO is considered challenging, as theoretical analysis suggests that they are unstable in this structure under ambient conditions. Here, we develop a bottom-up method for synthesizing Mn- and Fe-containing rocksalt HEO (FeO-HEO). We present a comprehensive investigation of its crystal structure and the random cation-site occupancy. We show the improved structural robustness of this FeO-HEO and verify the viability of an oxygen sublattice as a buffer layer. Compositional analysis reveals the valence and spin state of the iron species. We further report the antiferromagnetic order of this FeO-HEO below the transition temperature ~218 K and predict the conditions of phase stability of Mn- and Fe-containing HEOs. Our results provide fresh insights into the design and property tailoring of emerging classes of HEOs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Conasauga Shale Research Consortium (CSRC) (Final Report)

The objective of the Conasauga Shale Research Consortium (CSRC) project was to establish a field laboratory and utilize a horizontal well of opportunity to conduct a scientific study designed to advance the understanding of the petrophysical and geomechanical properties of the emerging Rogersville Shale unconventional oil and gas play. Unfortunately, just as the research program was beginning, our industry partner lost a primary investor in the horizontal well which was intended to be the ‘well of opportunity’ for the project. In a negotiated restructuring of the project by DOE-NETL and the Awardee consortium, additional time for Budget Period 1 was granted in the hopes that the industry partner could acquire additional investments to allow for the drilling of the horizontal well. This search was ultimately unsuccessful, and the consortium was unable to pass the negotiated Go/No-go Decision Point #1, which resulted in the termination of the project on July 31, 2021.

02 PETROLEUM↗

DOE OSTI2021

Universal Monte Carlo Event Generator

With the Jefferson Lab 12 GeV physics program underway and plans for the future Electron-Ion Collider (EIC), the nuclear physics community is entering a new era of exploration of QCD phenomena involving extensive data taking and event-level processing. This brings with it the potential for unprecedented access to multidimensional particle momentum distributions (PMDs) that can be connected to various theoretical frameworks by unfolding the emergent quantum mechanical properties of QCD using the PMDs. In practice, the PMDs are rendered as discretized histograms (typically one- or two-dimensional projections), and detector effects must be taken into account to unfold the pure detector effect-free PMDs that can be connected with theory. One of the challenges in this new era is obtaining faithful reconstructions of the multidimensional PMDs that preserve all of the inherent particle correlations. In this LDRD project we developed a novel approach using machine learning (ML) that solves this challenge, by avoiding entirely the need to use histograms as the main numerical technique to obtain the detector effect-free PMDs. The new approach is, moreover, scalable to higher dimensional PMDs. The central idea involves training neural networks (NNs) to generate synthetic event-level data (momenta 4-vectors of final state particles) to preserve all correlations among the particles. This is achieved by converting the trial synthetic vertex-level events to detector-level events using detector simulators. The NNs are then tuned using a specialized distance metric between the synthetic detector events and the real detector events.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

Energy-Efficient Self-Organization and Swarm Behavior in Active Matter

Living systems have the unique ability to form hierarchical assemblies, in which individual constituents can perform tasks cooperatively and emergently. Harnessing such properties is a long-standing challenge for the rational design of dynamic materials, that can respond to their environment, communicate with one another, and undergo a rapid, reversible, assembly through the transduction of energy. Recent developments in the design of smart and active colloidal building blocks have led to tremendous breakthroughs, with, for instance, the onset of synthetic photoactivated active assemblies. In this project, we develop a combined experimental, computational, theoretical and Machine Learning framework to shed light on the physical underpinnings of such assembly processes and program the assembly of smart active materials.

36 MATERIALS SCIENCE↗

NASA NTRS1990

Uses of Auger and x ray photoelectron spectroscopy in the study of adhesion and friction

Three studies are described characterizing the possible contributions of surface science to tribology. These include surface contamination formed by the interaction of a surface with the environment, contaminants obtained with diffusion of compounds, and surface chemical changes resulting from selective thermal evaporation. Surface analytical tools such as Auger electron spectroscopy (AES) and x ray photoelectron spectroscopy (XPS) incorporated directly into adhesion and friction systems are primarily used to define the nature of tribological surfaces before and after tribological experimentation and to characterize the mechanism of solid-to-solid interaction. Emphasis is on fundamental studies involving the role of surfaces in controlling the adhesion and friction properties of materials emerging as a result of the surface analyses. The materials which were studied include metals and ceramics such as elemental metals, amorphous alloys (metallic glasses), and silicon-based ceramics.

Miyoshi, Kazuhisa↗

NASA NTRS2003

Carbon-Nitrogen-Oxygen Line Radiation and the X-ray Bowen Fluorescence Mechanism in Optically Thick, Highly Ionized Media

Radiative transfer effects due to overlapping X-ray lines in a high-temperature, optically thick, highly ionized medium are investigated. One particular example, in which the O VIII Lyalpha doublet (2(sup 2) P(sub 1/2,3/2)-1(sup 2) S(sub 1/2) coincides in frequency with the N VII Lyzeta lines (7(sup 2) P(sub 1/2,3/2)-1(sup 2) S(sub 1/2) is studied in detail to illustrate the effects on the properties of the emergent line spectrum. We solve the radiative transfer equation to study the energy transport of resonance-line radiation in a static, infinite, plane-parallel geometry, which is used to compute the destruction/escape probabilities for each of the lines for various total optical thicknesses of the medium, as well as destruction probabilities by sources of underlying photoelectric opacity. It is found that a large fraction of the O vIII Lyalpha line radiation can be destroyed by N VII, which can result in a reversal of the O VIII Lyalpha/N VII Lyalpha line intensity ratio similar to what may be seen under nonsolar abundances. Photoelectric absorption by ionized carbon and nitrogen can also subsequently increase the emission-line intensities of these ions. We show that line ratios, which are directly proportional to the abundance ratios in optically thin plasmas, are not good indicators of the true CNO abundances. Conversely, global spectral modeling that assumes optically thin conditions may yield incorrect abundance estimates when compared with observations, especially if the optical depth is large. Other potentially important overlapping lines and continua in the X-ray band are also identified, and their possible relevance to recent high-resolution spectroscopic observations with Chandra and XMM-Newton are briefly discussed.

Sako, Masao↗

NASA NTRS2010

The Influence of Friction Stir Weld Tool Form and Welding Parameters on Weld Structure and Properties: Nugget Bulge in Self-Reacting Friction Stir Welds

Although friction stir welding (FSW) was patented in 1991, process development has been based upon trial and error and the literature still exhibits little understanding of the mechanisms determining weld structure and properties. New concepts emerging from a better understanding of these mechanisms enhance the ability of FSW engineers to think about the FSW process in new ways, inevitably leading to advances in the technology. A kinematic approach in which the FSW flow process is decomposed into several simple flow components has been found to explain the basic structural features of FSW welds and to relate them to tool geometry and process parameters. Using this modelling approach, this study reports on a correlation between the features of the weld nugget, process parameters, weld tool geometry, and weld strength. This correlation presents a way to select process parameters for a given tool geometry so as to optimize weld strength. It also provides clues that may ultimately explain why the weld strength varies within the sample population.

Schneider, Judy↗

DOE OSTI2021

Disturbance triggers non-linear microbe–environment feedbacks

Abstract. Conceptual frameworks linking microbial community membership, properties, and processes with the environment and emergent function have been proposed but remain untested. Here we refine and test a recent conceptual framework using hyporheic zone sediments exposed to wetting–drying transitions. Our refined framework includes relationships between cumulative properties of a microbial community (e.g., microbial membership, community assembly properties, and biogeochemical rates), environmental features (e.g., organic matter thermodynamics), and emergent ecosystem function. Our primary aim was to evaluate the hypothesized relationships that comprise the conceptual framework and contrast outcomes from the whole and putatively active bacterial and archaeal communities. Throughout the system we found threshold-like responses to the duration of desiccation. Membership of the putatively active community – but not the whole bacterial and archaeal community – responded due to enhanced deterministic selection (an emergent community property). Concurrently, the thermodynamic properties of organic matter (OM) became less favorable for oxidation (an environmental component), and respiration decreased (a microbial process). While these responses were step functions of desiccation, we found that in deterministically assembled active communities, respiration was lower and thermodynamic properties of OM were less favorable. Placing the results in context of our conceptual framework points to previously unrecognized internal feedbacks that are initiated by disturbance and mediated by thermodynamics and that cause the impacts of disturbance to be dependent on the history of disturbance.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS1980

Evidence for globally coherent variability in solar magnetic flux emergence

We examine the large-scale spatial and temporal variations in the emergence of X-ray bright points on the sun, in order to study the global properties of magnetic flux emergence. Major variations in the rate of flux emergence are observed at all solar latitudes, on a time scale of 3-5 months. The most economical explanation of the observations is that the full sun participated in a single large eruptive event during the available 8 month observing period from Skylab in 1973. The peak of this global event corresponds in time to the eruption of a major complex of activity. Moreover, it appears that the only portion of the solar surface which deviates from the above pattern of behavior is the low latitude region in the vicinity of the AR complex; this area shows a temporary depletion immediately following the AR outburst. The high-latitude regions in both hemispheres show the same variation and appear to lead the low-latitude emergence by approximately 1 month.

Golub, L.↗

DOE OSTI2021

Interlayer Triplet-Sensitized Luminescence in Layered Two-Dimensional Hybrid Metal-Halide Perovskites

In this work, we review an emerging class of 2D layered metal-halide perovskites that exhibit important photophysical behavior involving inorganic exciton-to-molecular triplet energy flow. These novel systems have potential to impact several energy-related fields and processes, including optoelectronics, photon upconversion strategies, and triplet-based photocatalysis. Early studies provided initial guidance and revealed several intriguing questions that more recent developments, in terms of both expanded and diversified compositional tuning and more sophisticated characterization, have begun to answer. These questions center around the delicate interplay between physical and electronic structure that is perturbed by choice of perovskite structural motif and organic spacer properties. In addition to their distinct natures, the energy offsets between the metal-halide and molecular excitons can be leveraged for a variety of unique effects and emergent properties, including fast interlayer energy transfer. We review the key advances with an eye toward strategies for controlling photophysical outcomes based on structure-energy-function relationships.

14 SOLAR ENERGY↗

NASA NTRS1986

The emergence of Zipf's law - Spontaneous encoding optimization by users of a command language

The distribution of commands issued by experienced users of a computer operating system allowing command customization tends to conform to Zipf's law. This result documents the emergence of a statistical property of natural language as users master an artificial language. Analysis of Zipf's law by Mandelbrot and Cherry shows that its emergence in the computer interaction of experienced users may be interpreted as evidence that these users optimize their encoding of commands. Accordingly, the extent to which users of a command language exhibit Zipf's law can provide a metric of the naturalness and efficiency with which that language is used.

Ellis, S. R.↗

DOE OSTI2021

Signatures of two-dimensional superconductivity emerging within a three-dimensional host superconductor

Significance We report signatures of a new phenomenon wherein a hidden “interdimensional” order emerges from a bulk three-dimensional superconductor tuned to approach a phase transition to an insulator. Prior electrical transport measurements found that the superconductor–insulator transition of BaPb 1− x Bi x O 3 demonstrated critical scaling behavior but inexplicably required parameters consistent only with two dimensions. Here, we directly image the three-dimensional superconducting state as it approaches an insulating phase and discover that signatures of a two-dimensional granular superconducting phase spontaneously emerge at the transition. Moreover, the properties of this phase precisely match the theory of emergent electronic granularity specific to two-dimensional materials. These findings posit that a three-dimensional superconductor electronically reorganizes itself into a two-dimensional granular superconductor before ultimately transforming to an insulator.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2023

Hybrid Monomer Design Synergizing Property Trade‐offs in Developing Polymers for Circularity and Performance

Abstract Current search for more sustainable plastics seeks to redesign polymers possessing both chemical recyclability to monomer for a circular plastics economy and desirable performance that can rival or even exceed today's non‐recyclable or hard‐to‐recycle petroleum‐based incumbents. However, within a traditional monomer framework it is challenging to optimize, concurrently , contrasting polymerizability/depolymerizability and recyclability/performance properties. Here, we highlight the emerging hybrid monomer design strategy to develop intrinsically circular polymers with tunable performance properties, aiming to unify desired, but otherwise conflicting, properties in a single monomer. Conceptually, this design hybridizes parent monomer pairs of contrasting, mismatching, or matching properties into offspring monomers that not only unify the above‐described conflicting properties but also radically alter the resultant polymer properties far beyond the limits of what either parent homopolymers or their copolymers can achieve.

Shi, Changxia↗

DOE OSTI2023

Hybrid Monomer Design Synergizing Property Trade‐offs in Developing Polymers for Circularity and Performance

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS2000

Hypergolic Propellant Safety Course

Under the sponsorship of the NASA Safety Training Center at the Johnson Space Center, a hypergolic propellant safety course has been developed. This is a 2-day course on guidelines for hypergolic propellant system design, materials selection, operations, storage, and transportation. Recognizing that numerous fuels and oxidizers can be hypergolic, this course is specific to the hydrazine family of fuels and nitrogen tetroxide and its variants. The objectives of the course are to enable the student to identify and evaluate the hazards of hypergolic propellants, and to understand the methods for controlling those hazards and responding to emergencies. The course covers properties and hazards of the hydrazines and oxidizers; design and operations in hypergolic facilities; materials selection for use in hypergol systems; storage vessels, piping, and component considerations; hypergol detection; fire fighting practices; operating and transportation principles and procedures; and emergency practices and considerations. A hazards analysis methodology is presented. Numerous references are provided and the applicability of certain regulatory documents is discussed. A brief overview of other propellants, including hydrogen peroxide, is given at the end of the course.

Rathgeber, Kurt A.↗

DOE OSTI2022

Understanding Metal–Organic Framework Nucleation from a Solution with Evolving Graphs

A mechanistic understanding of metal–organic framework (MOF) synthesis and scale-up remains underexplored due to the complex nature of the interactions of their building blocks. In this work, we investigate the collective assembly of building units at the early stages of MOF nucleation, using MIL-101(Cr) as a prototypical example. Using large-scale molecular dynamics simulations, we observe that the choice of solvent (water and N,N-dimethylformamide), the introduction of ions (Na+ and F–) and the relative populations of MIL-101(Cr) half-secondary building unit (half-SBU) isomers have a strong influence on the cluster formation process. Additionally, the shape, size, nucleation and growth rates, crystallinity, and short and long-range order largely vary depending on the synthesis conditions. We evaluate these properties as they naturally emerge when interpreting the self-assembly of MOF nuclei as the time evolution of an undirected graph. Solution-induced conformational complexity and ionic concentration have a dramatic effect on the morphology of clusters emerging during assembly. While pure solvents lead to the rapid formation of a small number of large clusters, the presence of ions in aqueous solutions results in smaller clusters and slower nucleation. This diversity is captured by the key features of the graph representation. Principle component analysis on graph properties reveals that only a small number of molecular descriptors is needed to deconvolute MOF self-assembly. Furthermore, descriptors such as the average coordination number between half-SBUs and fractal dimension are of particular interest as they can be can be followed experimentally by techniques like by time-resolved spectroscopy. Ultimately, graph theory emerges as an approach that can be used to understand complex processes revealing molecular descriptors accessible by both simulation and experiment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Ink-substrate interactions during 3D printing revealed by time-resolved coherent X-ray scattering

Additive printing techniques are regarded as revolutionary and versatile methods of advanced device manufacturing, stemming from the possibility to pattern materials on a custom-based approach and the potential to create novel microstructures and achieve new functionalities. Despite these advantages, the inherent anisotropy of the printing process is a source of property gradients within the printed materials, often associated with variable and/or poor performance. Up to date, the evolutionary pathways associated with printing have largely remained unaddressed, mainly owing to the difficulty to study the transformations induced in the material during processing. Time-resolved coherent X-ray scattering techniques, such as X-ray photon correlation spectroscopy, enable the in situ study of transient nanoscale and mesoscale states in a large variety of materials, including amorphous ones, by directly accessing the most relevant timescales and length scales of their nanoscale and mesoscale dynamics, self-assembly, and mesostructure evolution. In this work, we conduct in operando studies of continuous-flow direct writing with colloidal inks, focusing on how the ink formulation and ink-substrate interactions affect the processes that determine the macroscopic properties of the printed materials. We find fundamental differences in the ink structural relaxations emerging from the primary colloid properties (monodisperse versus aggregated colloids) and the substrates surface energy and mechanical properties. Our work helps to reveal and quantify the basic science governing the evolution of 3D-printed materials during processing, ultimately improving engineering criteria for the design of printable materials.

36 MATERIALS SCIENCE↗