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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Materials genome innovation for computational software (magics) center

Functional layered material (LM) architectures will dominate nanomaterials science in this century. We have developed theory, modeling, simulation, and software and data tools that enhance understanding and AI guide synthesis, enable characterization of complex structures, and improve capabilities in the predictive design and growth of LMs. Research at the Center has focused on: Computational synthesis and characterization: AI guided synthesis and experimental synthesis of stacked LMs with tailored properties via optimized chemical vapor deposition (CVD) growth and liquid-phase exfoliation; study defects, edges, grain boundaries, wrinkling of atomic layers and their effects on chemical, mechanical, electrical, and optical properties. Far-from-equilibrium processes: Joint experimental and simulation based probe of electronic processes with NAQMD and ultrafast X-ray free-electron laser (XFEL) and ultrafast electron diffraction (UED) facilities at Stanford. Experimentally validate NAQMD by ultrafast electron diffraction and X-ray spectroscopy studies of structural and excited state dynamics, shape fluctuations, and phonon dynamics. Scalable software: Simulation engines for desktop-to-exascale platforms using low-overhead, linear-scaling QMD algorithms; divide-conquer-recombine NAQMD with electronic excitations; extended-Lagrangian reactive molecular dynamics (RMD), machine learning (ML) based neural-network quantum molecular dynamics (NNQMD), and super-state accelerated molecular dynamics (AMD) and kinetic Monte Carlo codes; thermal and electrical transport software; and design 3D architectures of LMs with desired functionality using scalable software. Distribution of software and data, and training: Software and simulation-experimental data generated within the Center are distributed to the materials science community via Berkeley Materials Project (MP) framework. We have also organized three workshops for software distribution and training at USC (Nov. 2017, Mar. 2018) and Gaithersburg, MD (Nov. 2018) to train researchers, with the last one in focused on underrepresented groups, in collaboration with Howard University which is one of the largest HBCUs. The Center supported a total of 46 personnel and 6 undergraduate students. These include 14 faculty, 11 postdoctoral research associates, 20 graduate research assistants, and mentored 6 undergraduate students. This resulted in the publications of 63 research papers that include 46 publications on Reactive and Quantum Dynamics Simulations, 13 publications on Machine Learning for Quantum Materials, and 4 publications on Quantum Computing.

2D Materials↗
DOE OSTI2025

Extremely Durable Concrete using Methane Decarbonization Nanofiber Co-products with Hydrogen

This project successfully developed a scalable, low-cost co-production process for hydrogen (H₂) and carbon nanofibers (CNFs) using methane through catalytic chemical vapor deposition (CVD). CNFs are high-value materials with exceptional mechanical, electrical, and chemical properties, while hydrogen is a critical clean energy resource. By leveraging vapor deposition to create highly dispersed metal catalysts, this work addressed the dual challenge of producing low-cost hydrogen and enhancing the durability of concrete using co-produced CNFs. Unlike prior approaches, which required separating the carbon product from the catalyst, this innovative method integrated the carbon product, catalyst, and silica support as a crack-bridging additive for Portland cement. This novel application aimed to advance the performance of high-performance concrete (HPC) by improving its flexural toughness, durability, and resistance to environmental degradation.

08 HYDROGEN↗
DOE OSTI2025

In-Situ Laser Diagnostics to Understand Plasma-Surface Interactions in Titanium Thin Film Deposition

During the current project period the following tasks were completed: (1) We demonstrated the feasibility of a new way of measuring CH3 radicals in a plasma environment using a single, femtosecond (fs) pulsed laser for the first time, in a CH4 + Ar flow. A single fs pulsed Ti:Sa laser was split into two beams and with beam conversion using crystals we generatedtwo beams of 275 nm and 205 nm. The 275 nm was used to predissociate the CH3 radicals to CH2+H, followed by 205 nm Two Photon Laser Induced Fluorescence (TALIF) detection of H atoms, with a 11 ns delay from 275 nm predissociation pulse. (2) We demonstrated preliminary CH3 concentration measurements with spatial (< 100 µm) and time resolution (< 10 ns) by image processing of H and Kr TALIF signal images. (3) The methodology to quantify CH3 concentrations was developed. (4) Preliminary measurements of laser dissociation cross sections for CH4 and CH3 to (CH3+H), and (CH2+H), respectively, were conducted. (5) 275 nm laser dissociation of CH4 is a multiphoton process, and the CH4 dissociation cross section is a more sensitive function of the laser pulse energy than CH4 concentration. In the coming months, we will make more precise measurements of the dissociation cross sections, 𝑘275, 𝐶𝐻4 and 𝑘275, 𝐶𝐻3, by varying the laser energy while keeping the flow composition and conditions constant. This will enable more precise quantification of CH3 radical concentrations. More detailed measurements of CH3 radicals will be conducted in the following months of 2025 (Sept-Dec) in a Titanium Isopropoxide (TIP) + H2 + Ar flow meant for pure phase Ti thin film deposition by Chemical Vapor Deposition (CVD). More precise measurements of 275 nm laser dissociation cross sections for CH4 (to CH3 + H) and CH3 (to CH2 + H) will be conducted in the future. Detailed 275 nm laser predissociation cross sections for CH4 and CH3 dissociation to (CH3+H), and (CH2+H), respectively, as a function of gas heating, plasma power, and laser pulse energy will be evaluated. This will enable quantification of CH3 concentrations in the precursor flow over a substrate with time and spatial resolution. Comparison of the concentrations with 2D numerical simulations can lead to understanding of plasma surface interactions during pure metallic Ti thin film deposition using environmentally safer non-halogen TIP precursor. Flow conditions for pure Ti thin film deposition using non-halogen precursor (TIP) will be identified in the following months.

Uddi, Mruthunjaya [Advanced Cooling Technologies, ↗
DOE OSTI2026

Vulnerability Management for Electric Vehicle Supply Equipment

Vulnerability management for EVSE is a challenging undertaking with all the necessary stakeholders and devices that are interconnected, this presentation reviews the challenges and opportunities for conducting CVD for EVSE.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

From Prevention to Disease Perturbations: A Multi-Omic Assessment of Exercise and Myocardial Infarctions

While a molecular assessment of the perturbations and injury arising from diseases is essential in their diagnosis and treatment, understanding changes due to preventative strategies is also imperative. Currently, complex diseases such as cardiovascular disease (CVD), the leading cause of death worldwide, suffer from a limited understanding of how the molecular mechanisms taking place following preventive measures (e.g., exercise) differ from changes occurring due to the injuries caused from the disease (e.g., myocardial infarction (MI)). Therefore, this manuscript assesses lipidomic changes before and one hour after exercise treadmill testing (ETT) and before and one hour after a planned myocardial infarction (PMI) in two separate patient cohorts. Strikingly, unique lipidomic perturbations were observed for these events, as could be expected from their vastly different stresses on the body. The lipidomic results were then combined with previously published metabolomic characterizations of the same patients. This integration provides complementary insights into the exercise and PMI events, thereby giving a more holistic understanding of the molecular changes associated with each.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Carbon Nanotube Formation on Cr-Doped Ferrite Catalyst during Water Gas Shift Membrane Reaction: Mechanistic Implications and Extended Studies on Dry Gas Conversions

A nanocrystalline chromium-doped ferrite (FeCr) catalyst was shown to coproduce H2 and multiwalled carbon nanotubes (MWCNTs) during water gas shift (WGS) reaction in a H2-permselective zeolite membrane reactor (MR) at reaction pressures of ~20 bar. The FeCr catalyst was further demonstrated in the synthesis of highly crystalline and dimensionally uniform MWCNTs from a dry gas mixture of CO and CH4, which were the apparent sources for MWCNT growth in the WGS MR. In both the WGS MR and dry gas reactions, the operating temperature was 500 °C, which is significantly lower than those commonly used in MWCNT production by chemical vapor deposition (CVD) method from CO, CH4, or any other precursor gases. Extensive ex situ characterizations of the reaction products revealed that the FeCr catalyst remained in partially reduced states of Fe3+/Fe2+ and Cr6+/Cr3+ in WGS membrane reaction while further reduction of Fe2+ to Fe0 occurred in the CO/CH4 dry gas environments. The formation of the metallic Fe nanoparticles or catalyst surface dramatically improved the crystallinity and dimensional uniformity of the MWCNTs from dry gas reaction as compared to that from WGS reaction in the MR. Reaction of the CO/CH4 mixture containing 500 ppmv H2S also resulted in high-quality MWCNTs similar to those from the H2S-free feed gas, demonstrating excellent sulfur tolerance of the FeCr catalyst that is practically meaningful for utilization of biogas and cheap coal-derived syngas.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Epitaxial Growth of Ga2O3: A Review

Beta-phase gallium oxide (β-Ga2O3) is a cutting-edge ultrawide bandgap (UWBG) semiconductor, featuring a bandgap energy of around 4.8 eV and a highly critical electric field strength of about 8 MV/cm. These properties make it highly suitable for next-generation power electronics and deep ultraviolet optoelectronics. Key advantages of β-Ga2O3 include the availability of large-size single-crystal bulk native substrates produced from melt and the precise control of n-type doping during both bulk growth and thin-film epitaxy. A comprehensive understanding of the fundamental growth processes, control parameters, and underlying mechanisms is essential to enable scalable manufacturing of high-performance epitaxial structures. This review highlights recent advancements in the epitaxial growth of β-Ga2O3 through various techniques, including Molecular Beam Epitaxy (MBE), Metal-Organic Chemical Vapor Deposition (MOCVD), Hydride Vapor Phase Epitaxy (HVPE), Mist Chemical Vapor Deposition (Mist CVD), Pulsed Laser Deposition (PLD), and Low-Pressure Chemical Vapor Deposition (LPCVD). This review concentrates on the progress of Ga2O3 growth in achieving high growth rates, low defect densities, excellent crystalline quality, and high carrier mobilities through different approaches. It aims to advance the development of device-grade epitaxial Ga2O3 thin films and serves as a crucial resource for researchers and engineers focused on UWBG semiconductors and the future of power electronics.

Chemistry↗
DOE OSTI2024

Over 600 V Lateral AlN-on-AlN Schottky Barrier Diodes with Ultra-Low Ideality Factor

Abstract This letter reports the demonstration of lateral AlN Schottky barrier diodes (SBDs) on single-crystal AlN substrates by metalorganic CVD (MOCVD) with an ultra-low ideality factor ( η ) of 1.65, a high Schottky barrier height of 1.94 eV, a breakdown voltage ( BV ) of 640 V, and a record high normalized BV by the anode-to-cathode distance. The device current was dominated by thermionic emission, while most previously reported AlN SBDs suffered from defect-induced current with higher η (>4). This work represents a significant step towards high-performance ultra-wide bandgap AlN-based high-voltage and high-power devices.

Physics↗
DOE OSTI2021

High-efficiency transmission-mode diamond scintillator for quantitative characterization of X-ray beams

The luminance of a transmission mode X-ray scintillator diamond plate is dominated by induced defect centers having an excited state lifetime less than 10 msec, and in embodiments less than 1 msec, 100 usec, 10 used, 1 used, 100 nsec, or even 50 nsec, thereby providing enhanced X-ray luminance response and an X-ray flux dynamic range that is linear with X-ray flux on a log-log scale over at least three orders of magnitude. The diamond plate can be a single crystal having a dislocation density of less than 104 per square centimeter, and having surfaces that are ion milled instead of mechanically polished. The defect centers can be SiV centers induced by silicon doping during CVD diamond formation, and/or NV0 centers formed by nitrogen doping followed by applying electron beam irradiation of the diamond plate and annealing.

Antipov, Sergey↗
DOE OSTI2022

Proton selective membranes based on two dimensional materials

Proton conductive membrane includes a proton selective layer of 80-100% carbon with sp2 hybridization having a thickness of 0.3-100 nm, with 0-20% of hydrogen, oxygen, nitrogen and sp3 carbon; wherein the sp2 carbon is in a form of graphene-like material; the proton selective layer having a plurality of pores formed by any of 7, 8, 9 or 10 sp2 carbon cycles or a combination thereof, with the pores having an effective diameter of up to 0.6 nm; an ionomeric polymer layer on the proton selective layer. Total thickness of the proton conductive membrane is less than 50 microns. The ionomeric polymer is PFSA (perfluorinated sulfonic acid), PVP (polyvinylpyrrolidone) or PVA (poly vinyl alcohol) with iodide or bromide counterion dissolved inside. The graphene-like material is CVD graphene or reduced graphene oxide (rGO). A D to G Raman band ratio of the membrane is more than 0.1.

Smirnov, Sergei↗
DOE OSTI2023

Development of Large-Volume-Diamond Anvil Cell for Neutron Diffraction: The Neutron Diamond Anvil Cell Project at ORNL

10 years ago, Dave Mao, director of EFree (energy frontier research in extreme environments), a DOE energy frontier recognized the importance of neutron science for energy research. The subsequent establishment of a neutron group within EFree lead to the establishment of an “Instrument Development Team” for SNAP, the High-Pressure beamline at the Spallation Neutron Source at Oak Ridge National Laboratory in Tennessee. The idea was to develop novel high pressure techniques to expand the pressure range for neutron diffraction. A goal was set to reach half megabar levels (50 GPa), which at the time was considered as extremely challenging. Here we will give a brief overview of the developments during the last decade in this novel area of research. Fortunately, during this period multi carat diamond anvils have become available mainly by the chemical vapor deposition process (CVD), making research in this pressure range and beyond rather routine. This paper shows the latest developments in large anvil designs, compact multiple ton diamond cells and some examples of high-quality neutron diffraction patterns of sample sizes far below conventional levels.

Boehler, Reinhard↗
DOE OSTI2023

Graphene nanoribbons grown from aromatic molecular seeds

Methods for the bottom-up growth of graphene nanoribbons are provided. The methods utilize small aromatic molecular seeds to initiate the anisotropic chemical vapor deposition (CVD) growth of graphene nanoribbons having low size polydispersities on the surface of a growth substrate. The aromatic molecular seeds include polycyclic aromatic hydrocarbons (PAHs), functionalized derivatives of PAHs, heterocyclic aromatic molecules, and metal complexes of heterocyclic aromatic molecules.

Arnold, Michael Scott↗
DOE OSTI2023

Method of manufacturing proton selective membranes based on two dimensional materials

Proton conductive membrane includes a proton selective layer of 80-100% carbon with sp2 hybridization having a thickness of 0.3-100 nm, with 0-20% of hydrogen, oxygen, nitrogen and sp3 carbon; wherein the sp2 carbon is in a form of graphene-like material; the proton selective layer having a plurality of pores formed by any of 7, 8, 9 or 10 sp2 carbon cycles or a combination thereof, with the pores having an effective diameter of up to 0.6 nm; an ionomeric polymer layer on the proton selective layer. Total thickness of the proton conductive membrane is less than 50 microns. The ionomeric polymer is PFSA (perfluorinated sulfonic acid), PVP (polyvinylpyrrolidone) or PVA (poly vinyl alcohol) with iodide or bromide counterion dissolved inside. The graphene-like material is CVD graphene or reduced graphene oxide (rGO). A D to G Raman band ratio of the membrane is more than 0.1.

Smirnov, Sergei↗
DOE OSTI2023

Direct Alpha Spectrometry of Nuclear Fallout

Advanced instruments and methods are under development to allow direct alpha spectrometry of nuclear fallout debris near the point of collection, to support nuclear forensics (NF). New approaches are needed to support NF in order to accelerate the process for data generation and reduce the overall timeline for decision making. Fallout debris at short time periods following detonation can be difficult to work with for alpha spectrometry, due to the presence of intense beta radiation originating from significant quantities of high-activity fission products. Intense beta radiation can challenge traditional silicon-based high-resolution alpha spectrometers. Addressing this, single-crystal (sc) chemical vapor deposition (CVD) produced diamond semiconductors have been studied for use for alpha spectrometry for assaying nuclear fallout debris. Tests have been performed using scCVD sensors to assay a variety of actinide-bearing samples. Sample preparation, when done, has been limited to pulverization using a mechanical ball mill. To reduce measurement times, multi-chip arrays of scCVD diamond semiconductor have been developed in form factors suitable for field deployment in support of NF objectives. These arrays have been tested using high-beta-activity sol gel surrogate nuclear explosive debris (SNED) containing varying concentrations of uranium and plutonium. Results from the use of scCVD detectors with sol gel SNED will be presented.

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗
DOE OSTI2023

Controlled Growth of Single‐Crystal Graphene Wafers on Twin‐Boundary‐Free Cu(111) Substrates

Single-crystal graphene (SCG) wafers are needed to enable mass-electronics and optoelectronics owing to their excellent properties and compatibility with silicon-based technology. Controlled synthesis of high-quality SCG wafers can be done exploiting single-crystal Cu(111) substrates as epitaxial growth substrates recently. However, current Cu(111) films prepared by magnetron sputtering on single-crystal sapphire wafers still suffer from in-plane twin boundaries, which degrade the SCG chemical vapor deposition. Here, in this study, it is shown how to eliminate twin boundaries on Cu and achieve 4 in. Cu(111) wafers with ≈95% crystallinity. The introduction of a temperature gradient on Cu films with designed texture during annealing drives abnormal grain growth across the whole Cu wafer. In-plane twin boundaries are eliminated via migration of out-of-plane grain boundaries. SCG wafers grown on the resulting single-crystal Cu(111) substrates exhibit improved crystallinity with >97% aligned graphene domains. As-synthesized SCG wafers exhibit an average carrier mobility up to 7284 cm 2 V −1 s −1 at room temperature from 103 devices and a uniform sheet resistance with only 5% deviation in 4 in. region.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Armor for Steel: Facile Synthesis of Hexagonal Boron Nitride Films on Various Substrates

Abstract While hexagonal boron nitride (hBN) has been widely used as a buffer or encapsulation layer for emerging electronic devices, interest in utilizing it for large‐area chemical barrier coating has somewhat faded. A chemical vapor deposition process is reported here for the conformal growth of hBN on large surfaces of various alloys and steels, regardless of their complex shapes. In contrast to the previously reported very limited protection by hBN against corrosion and oxidation, protection of steels against 10% HCl and oxidation resistance at 850 °C in air is demonstrated. Furthermore, an order of magnitude reduction in the friction coefficient of the hBN coated steels is shown. The growth mechanism is revealed in experiments on thin metal films, where the tunable growth of single‐crystal hBN with a selected number of layers is demonstrated. The key distinction of the process is the use of N 2 gas, which gets activated exclusively on the catalyst's surface and eliminates adverse gas‐phase reactions. This rate‐limiting step allowed independent control of activated nitrogen along with boron coming from a solid source (like elemental boron). Using abundant and benign precursors, this approach can be readily adopted for large‐scale hBN synthesis in applications where cost, production volume, and process safety are essential.

2D materials↗
DOE OSTI2022

On the importance of color in mass spectrometry imaging

Mass spectrometry imaging (MSI) data visualization relies on heatmaps to show the spatial distribution and measured abundances of molecules within a sample. Non-uniform color gradients such as jet are still commonly used to visualize MSI data, increasing the probability of data misinterpretation and false conclusions. Also, the use of non-uniform color gradients and the combination of hues used in common colormaps makes it challenging for people with color vision deficiencies (CVDs) to visualize and accurately interpret data. Here we present best practices for choosing a colormap to accurately display MSI data, improve readability, and accommodate all CVDs. We also provide other resources on the misuse of color in the scientific field and resources on scientifically derived colormaps presented herein.

47 OTHER INSTRUMENTATION↗