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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 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Dataset for scientific paper "Simulated plant‑mediated oxygen input has strong impacts on fine‑scale porewater biogeochemistry and weak impacts on integrated methane fluxes in coastal wetlands", a modeling study based on field observation at the tidal salt marshes of the Parker River Estuary, Massachusetts, United States

This dataset is the raw and processed data for the paper "Simulated plant ‑ mediated oxygen input has strong impacts on fine ‑ scale porewater biogeochemistry and weak impacts on integrated methane fluxes in coastal wetlands". This study investigated how plant-mediated oxygen input affects subsurface biogeochemical reactions of organic carbon degradation and the resulting methane emissions of coastal wetlands by model simulation. We used the subsurface geochemical simulator PFLOTRAN for the modeling, which produced the simulated changes in porewater chemical substances and methane emissions over 10 days under different scenarios of plant-mediated oxygen input.Specifically, this dataset contains: 1) the input files for PFLOTRAN of all simulation runs conducted in this study. Those files are with an extension of ".in", containing information of the biogeochemical reaction network (stoichiometry, reaction rate, Monod constants, etc), fluid flow rate and oxygen concentration in the fluid which together simulated the plant-mediated oxygen input, the configuration of artificial reactions that simulated the methane fluxes, etc. The PFLOTRAN input files are text files, which can be opened by NotePad, but running these input files will require proper installation of PFLOTRAN (instruction: https://documentation.pflotran.org/user_guide/how_to/installation/installation.html). 2) the raw and processed model output from PFLOTRAN of all simulation runs, and 3) the python scripts used to process the raw model output, including random allocation of root cells, converting raw data into organized formats, calculating the methane fluxes based on the model output, data visualization, etc. The raw and processed model output from PFLOTRAN are in .spydata format, which can be viewed with Python. and 3) the python scripts for data processing and analysis are programming scripts, which can be opened with Python.This modeling work, in particular the model parameterization of root density and initial conditions of porewater concentrations of biogeochemical substances, was based on field measurements at the salt marsh of the Upper Parker River Estuary, Massachusetts, United States.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Stiff and strong, lightweight bi-material sandwich plate-lattices with enhanced energy absorption

Plate-based lattices are predicted to reach theoretical Hashin–Shtrikman and Suquet upper bounds on stiffness and strength. However, simultaneously attaining high energy absorption in these plate-lattices still remains elusive, which is critical for many structural applications such as shock wave absorber and protective devices. In this article, we present bi-material isotropic cubic + octet sandwich plate-lattices composed of carbon fiber-reinforced polymer (stiff) skins and elastomeric (soft) core. This bi-material configuration enhances their energy absorption capability while retaining stretching-dominated behavior. We investigate their mechanical properties through an analytical model and finite element simulations. Our results show that they achieve enhanced energy absorption approximately 2–2.8 times higher than their homogeneous counterparts while marginally compromising their stiffness and strength. When compared to previously reported materials, these materials achieve superior strength-energy absorption characteristics, making them an excellent candidate for stiff and strong, lightweight energy absorbing applications.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Bioinspired synthesis of thermally stable and mechanically strong nanocomposite coatings

Abstract An innovative biomimetic method has been developed to synthesize layered nanocomposite coatings using silica and sugar-derived carbon to mimic the formation of a natural seashell structure. The layered nanocomposites are fabricated through alternate coatings of condensed silica and sugar. Sugar-derived carbon is a cost-effective material as well as environmentally friendly. Pyrolysis of sugar will form polycyclic aromatic carbon sheets, i.e., carbon black. The resulting final nanocomposite coatings can survive temperatures of more than 1150 °C and potentially up to 1650 °C. These coatings have strong mechanical properties, with hardness of more than 11 GPa and elastic modulus of 120 GPa, which are 80% greater than those of pure silica. The layered coatings have many applications, such as shielding in the form of mechanical barriers, body armor, and space debris shields. Graphical abstract

36 MATERIALS SCIENCE↗
DOE OSTI2021

The Accelerator Design Progress for EIC Strong Hadron Cooling

The Electron-Ion Collider will achieve a luminosity of 1034 cm-2 s-1 by incorporating strong hadron cooling to counteract hadron Intra-Beam Scattering, using a coherent electron cooling scheme. An accelerator will deliver the beams with key parameters, such as 1 nC bunch charge, and 1e-4 energy spread. The paper presents the design and beam dynamics simulation results. Methods to minimize beam noise, the challenges of the accelerator design, and the R&D topics being pursued are discussed.

Wang, E.↗
DOE OSTI2024

Proposal for a proton-bunch compression experiment at IOTA in the strong space-charge regime

The longitudinal compression of intense proton bunches with strong space-charge force is an essential component of a proton-based muon source for a muon collider. This paper discusses a proton-bunch compression experiment at the Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab to explore optimal radio frequency (RF) cavity and lattice configurations. IOTA is a compact fixed-energy storage ring that can circulate a 2.5-MeV proton beam with varying beam parameters and lattice configurations. The study will aim to demonstrate a bunch-compression factor of at least 2 in the IOTA ring while examining the impact of intense space-charge effects on the compression process.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Electron Ion Collider Strong Hadron Cooling Injector and ERL

Intra-beam Scattering (IBS) and other diffusion mechanisms in the EIC Hadron Storage Ring (HSR) degrade the beam emittances during a store, with growth times of about 2 hours at the nominal proton energies of 275GeV, 100 GeV, and 41 GeV. Strong Hadron Cooling (SHC) can maintain good hadron beam quality and high luminosity during long collision stores. A novel cooling method ’ Coherent electron Cooling (CeC) ’ is chosen as the baseline SHC method, due to its high cooling rates. An Energy Recovery Linac (ERL) is used to deliver an intense high-quality electron beam for cooling. In this paper, we discuss the beam requirements for SHC-CeC and describe the current status of the injector and ERL designs. Two designs of injector and ERL will be presented: one for dedicated SHC and another one for SHC with precooler.

Wang, E.↗
DOE OSTI2021

deeplenstronomy: A dataset simulation package for strong gravitational lensing

Automated searches for strong gravitational lensing in optical imaging survey datasets often employ machine learning and deep learning approaches. These techniques require more example systems to train the algorithms than have presently been discovered, which creates a need for simulated images as training dataset supplements. This work introduces and summarizes deeplenstronomy, an open-source Python package that enables efficient, large-scale, and reproducible simulation of images of astronomical systems. A full suite of unit tests, documentation, and example notebooks are available at https://deepskies.github.io/deeplenstronomy/ .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

From Interstellar Cloud to Star to Laboratory: Frontier HEDP Studies of Magnetized Colliding Plasma Flows with Strong Radiative Cooling (Final Report)

High-speed flows of gas are the norm in astrophysics where exploding stars, winds from the regions around black holes and streams of galactic material create “supersonic flows”. As the flows collide, strong shock waves are formed where gas is compressed and heated. The regions behind these shock waves are of great interest to scientists. New stars can form in these shock regions in the context of galaxies. In the context of planets like our Earth, the shocks waves come from the interaction of the solar wind with our planets’ magnetic field causing Aurora and placing astronauts and satellites in jeopardy. Thus, understanding supersonic flows of magnetized plasmas is essential for progress in many fields of astronomy and space physics (relevant to planets and the Earth). Remarkably, we can also create these kinds of flows in the laboratory using Z-pinches and laser driven experiments that include magnetic fields. The exploration of these forms of “High Energy Density Physics” (HEDP) flows is also critical in order to achieve Inertial Confinement Fusion, which is a step towards developing a sustainable source of Fusion energy.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

High-Performance Computational Modeling of Strong Ground Motion for Seismic Response Analysis with Implications for High-Hazard and/or Nuclear Facilities and Critical Infrastructure at the NNSSNLV-015-19, Year 2

Presentation to be given at the FY 2020 SDRD Annual Meeting, to be held Sept. 23-24, on WebEx. There is one video also attached. This presentation is a reduced slide deck of the recently STIPped version, DOE/NV/03624--0875, presented 9-15-20 at the work in progress seminar. High-Performance Computational Modeling of Strong Ground Motion for Seismic Response Analysis with Implications for High-Hazard and/or Nuclear Facilities and Critical Infrastructure at the NNSSNLV-015-19, Year 2

58 GEOSCIENCES↗
DOE OSTI2021

Spin-Coherent Transport under Strong Spin-Orbit Interaction (Final Technical Report)

The major goals of the project consisted of acquiring insight in spin-dependent quantum coherent electronic transport phenomena arising from spin-orbit interaction, via experiments on semiconductor heterostructures and thin film semimetals patterned into mesoscopic and nanoscale geometries. The solid-state physics findings contain insight potentially useful for the creation of new quantum states of matter, for spin operations in quantum information processing, for future spin electronics, and for other future functionalities of power-saving electronic devices. The subject was of fundamental interest, but was also of long-term applied interest for quantum devices, spintronics devices, and general electronic devices. The experiments were conducted by low-temperature electronic magnetotransport in nanoscale structures of length scales similar to the quantum phase- and spin-coherence lengths and the carrier mean-free paths in the materials. Emphasis was placed on quantum coherence and spin coherence, to understand coherent spin-dependent electronic processes, on transport of electrons with very long mean-free path (ballistic transport), on the transfer of electron spin to nuclear spin (dynamic nuclear spin polarization in bismuth), and on the study of materials with quantum states emerging from spin-orbit interaction and electron-electron interaction (bismuth iridates). In two-dimensional electron systems in quantum wells of the narrow-bandgap semiconductors InAs and InGaAs the objectives included the characterization of quantum states arising from the Aharonov-Casher quantum-mechanical phase as an electromagnetic dual of the Aharonov-Bohm phase. Objectives also included quantum electronic transport at the mesoscopic scale on the semimetal bismuth in thin film form, and particularly on its strongly spin-orbit coupled surface states. An almost-strain-free method was developed to grow high-quality bismuth thin films. Devices fabricated on these films were then used to study a novel nuclear spin torque, whereby the bismuth carrier spin was transferred to the bismuth nuclei by the agency of both spin-orbit interaction and hyperfine interaction. Aspects of ballistic transport were studied in GaAs/AlGaAs heterostructures of very high mobility, and a hitherto unsuspected similarity was discovered between ballistic transport and hydrodynamic transport, of potential use in future power-saving electronic devices.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Dynamics and Transport in Strongly-Anisotropic Quantum Magnets (Final Report)

This DOE Award has evolved from a set of projects centered on the thermal transport phenomena in quantum magnets to the broader effort in the theory of dynamical properties of complex magnets, with the focus on their enigmatic ground states, disorder-induced phenomena, and novel spectroscopic and transport effects in them. Most recent emphasis of the research under the umbrella of this Award has been on the rare-earth- and transition-metal-based strongly-anisotropic magnets, the effort that has utilized a significant experience of our group in the studies of excitations, transport, and disorder in these new materials. The studies performed in our group have advanced basic understanding of fundamental physical properties of a diverse group of materials and yielded predictions of new phenomena in them. The research under this Award has targeted the problems that are at the forefront of the modern condensed matter physics and has also addressed the need for the theoretical understanding of experiments. Our work has influenced experiments conducted at the national and international facilities and provided an impact on the DOE basic energy science missions and areas of thrust in new electronic materials, energy transport, neutron- and X-ray scattering science, and in nanoscale science.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Quantum Chemical Treatment of Strongly Correlated Magnetic Systems Based on Heavy Elements. Final Report

The objective of this project over the years has been to develop novel quantum chemical methods and employ them to study the chemistry of systems containing actinides, and transactinides. We have focused on their electronic and spectroscopic properties, their reactivity and utilization as single molecule magnets. We have developed wave-function based methods that are optimal to treat strongly correlated systems, namely systems with many electronic configurations that are all important and should be treated on an equal foot. Moreover, relativistic effects have to be included in the model, with special focus on spin-orbit coupling. We have derived our theories and developed our codes and made them available to the community as parts of open source packages. We have modelled systems in collaboration with experimentalists in the program, so that we could address some of the questions that are relevant to this community. We have also worked in collaboration with people at Lawrence Livermore National Laboratories on a project on super-heavy atoms. We hope that our theoretical predictions will inspire novel experiments. We have trained about 10 students/postdocs during this period, which are now faculty, researchers at national laboratories and in companies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Exploring strongly correlated quantum spin systems with quantum computers

At inception, quantum annealing leveraged quantum mechanics for classical optimization tasks. However, as machine coherence increases, the realization of quantum spin systems has emerged as an even more fruitful application of this computational model. Alternatives to the standard gate model deserve exploration, to achieve useful quantum advantage via analog quantum computing. The recent demonstration of so-called coherent quantum annealing with 1,000s of qubits, further expands the potential for this hardware to explore quantum system dynamics where the effects of quantum fluctuations can be carefully controlled and observed directly. Implementing existing celebrated spin models—or in fact new and dedicated ones—into quantum annealers will lead to observation and detection of quantum phenomena not yet observed, or not visualized directly, in experimental physics laboratories. Rather than computing or simulating quantum systems, these quantum computers allow one to simply build quantum systems, and experiment on them in an uniquely controlled way, with characterization down to the constitutive degree of freedom. This provides an unprecedented opportunity for understanding the physics of quantum spin systems. Keywords: Theoretical physics currently abounds of interesting theoretical spin models to explore frustration, strongly correlated spins, spin liquids, fractionalized excitations, and topological matter. However enticing, such models are generally only weak proxies for the properties of actual materials. In quantum annealers these models could be realized and experimented upon. Moreover, many more realistic models of such materials could be realized in quantum annealers. Employed in this way, quantum annealers provide an extraordinary versatile platform to explore quantum effects that are hard to find, detect, and characterize in natural materials.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Effects of a strong applied magnetic field on relativistic laser-plasma interactions

This project investigated the role played by strong external magnetic fields in laser-matter interactions at relativistic intensities and their impact of resulting high-energy density phenomena. The regimes that can benefit from currently available or soon to be available magnetic fields have been identified. The applications of this project include laser-driven ion acceleration and laser-driven plasma heating.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Possible routes to a strong science case for a joint CLEoPATRA-Roman microlensing survey

The Contemporaneous LEnsing Parallax and Autonomous TRansient Array (CLEoPATRA) is a mis sion concept for a space-based microlensing survey, proposed to enhance science for the Roman Space Telescope (RST) microlensing survey. From CLEoPATRA’s planned vantage point in geosynchronous equatorial orbit (GEO), it will observe microlensing events simultaneously and from a different point of view to RST at L2. This joint L2-GEO observation baseline gives a projected angular separation of order the size of the characteristic angular lensing scale of Free-Floating-Planets (FFPs) in the Galaxy, making it powerful for constraining FFP properties. We find that a strong science case will demonstrate which parts of the FFP parameter space a joint RST-CLEoPATRA survey will give lead ing lens constraints compared with competing ground- and space- based RST observatory companions (e.g., PRIME, Euclid). Both the simulations and framework that connect telescope capabilities to physical constraints already exist for RST FFPs and can be used to demonstrate the power of joint RST-CLEoPATRA survey, with the addition of a simulated CLEoPATRA event blending distribution. Population-level FFP constraints could also be calculated by adapting ongoing black hole microlensing research at Lawrence Livermore National Laboratory. We also find that considering CLEoPATRA as a third space-based observatory (in addition to RST and Euclid/PRIME), which will break microlensing degeneracies leading to unambiguous FFP constraints, is worth investigating as part of a science case. Finally, we highlight possible auxiliary CLEoPATRA science cases including relieving tension between the RST Core Community Surveys.

79 ASTRONOMY AND ASTROPHYSICS↗