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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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DOE OSTI2022

A boundary-based approach to the multiscale microstructural characterization of a W-Ni-Fe tungsten heavy alloy

Here, a combination electron backscattered diffraction and transmission electron microscopy based approach has been implemented to study the effects of purposefully introduced anisotropy in a tungsten heavy alloy (WHA) through hot-rolling. Particular attention has been paid to changes in number and proportion of various boundary types from a quantitative standpoint; incorporating qualitative behavioral observations from prior analyses to generate experimentally-validated bases for the examination and application of a microstructure which exhibits an optimal balance of strength and ductility. It is asserted that a combination of increased temperatures during rolling and additional isothermal hold time for the post-rolling annealing steps may lead to a reduction in unfavorable textural components due to rolling in the W-phase and a decrease in premature fracture due to W-W microcracking respectively. This is expected to further increase the proportion of interphase boundaries and improve the ductility of these rolled structures, producing a superior rolled WHA microstructure.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Understanding the origin of Tabula Rasa-induced defects in n-type Cz c-Si: The case of nitrogen atmosphere

Phosphorus-doped Czochralski-grown silicon (Cz-Si) has been gaining market share in the large-scale manufacturing of high-efficiency silicon (Si)-based photovoltaic (PV) devices thanks to higher carrier lifetimes than their boron-doped counterpart. However, the fabrication of n-type Cz-Si based solar cells often requires process steps with much higher temperatures and longer times than p-type Silicon. Defect interaction with the high temperatures during such processes tend to be detrimental to the n-type Cz-Si carrier lifetime, therefore limiting the final device efficiency. Short thermal anneals before cell processing, known as Tabula Rasa (TR), have been proposed to mitigate the thermally induced lifetime degradation during n-type Cz-Si solar cell fabrication. This work thoroughly investigates the defects responsible for the lifetime degradation after TR in a N 2 atmosphere treatment. We use temperature-injection-dependent lifetime spectroscopy and the thickness variation method to decouple the effects of TR treatment in the bulk and the surface of the n-type Cz-Si wafers. Using the defect parameter contour mapping (DPCM), we identify the defect energy level (E t ) and the capture cross-section ratio (k) of the most likely process-induced defect, which aligns with previously proposed Si vacancy-associated defects. The DPCM reveals that these vacancy-associated defects have a shallow energy level E t - E v ~0.13 eV and very efficient electron capture cross section k~600. Unexpectedly, the bulk degradation due to vacancy defects in the volume of the wafer, is accompanied by a significant increase in the surface recombination as well. Through evaluating the surface recombination velocity temperature- and injection dependence, we show that after TR, at room temperature and for an injection level of 10 15 cm -3 , in a wafer passivated with a-Si:H(i) the surface recombination dominates the overall lifetime response. Here we hypothesize that the near surface vacancy-associated bulk defects play a role in lowering the electron diffusion current into the a-Si:H(i) from the c-Si(n) reducing the field-effect passivation.

14 SOLAR ENERGY↗

DOE OSTI2025

Dissipation Pathways in a Photosynthetic Complex

Determining how energy flows within and between molecules is crucial for understanding chemical reactions, material properties, and even vital processes such as photosynthesis. While the general principles of energy transfer are well established, elucidating the specific molecular pathways by which energy is funneled remains challenging, as it requires tracking energy flow in complex molecular environments. Here, we demonstrate how photon excitation energy is partially dissipated in the light-harvesting Fenna–Matthews–Olson (FMO) complex, mediating the excitation energy transfer from light-harvesting chlorosomes to the photosynthetic reaction center in green sulfur bacteria. Specifically, we isolate the contribution of the protein and specific vibrational modes of the pigment molecules to the energy dynamics. For this, we introduce an efficient computational implementation of a recently proposed theory of dissipation pathways for open quantum systems, based on second-order perturbation theory in the electronic couplings. Using it and a state-of-the-art FMO model with highly structured and chromophore-specific spectral densities, we demonstrate that energy dissipation is dominated by low-frequency modes (<800 cm –1 ) as their energy range is near-resonance with the energy gaps between electronic states of the pigments. We identify the most important modes for dissipation to be in-plane breathing modes (∼200 cm –1 ) of the bacteriochlorophylls in the complex. Conversely, far-detuned intramolecular vibrations with higher frequencies (>800 cm –1 ) play no role in dissipation. Interestingly, the FMO complex first needs to borrow energy from the environment to release excess photonic energy, indicating that the energy exchange between the system and thermal environment is not strictly unidirectional in time but involves a transient thermally activated step. Beyond their fundamental value, these insights can guide the development of artificial light-harvesting devices and, more broadly, engineer environments for chemical and quantum control tasks.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Biomimetic Rebuilding of Multifunctional Red Blood Cells: Modular Design Using Functional Components

The design and synthesis of artificial materials that mimic the structures, mechanical properties, and ultimately functionalities of biological cells remains a current holy grail of materials science. Here based on a silica cell bio-replication approach, we report the design and construction of synthetic rebuilt red blood cells (RRBCs) that fully mimic the broad properties of native RBCs: size, biconcave shape, deformability, oxygen carrying capacity, long circulation time. Four successive nano-scale processing steps: RBC bioreplication, layer-by-layer polymer deposition, and precision silica etching, followed by RBC ghost membrane vesicles fusion are employed for RRBC construction. A panel of physicochemical analyses including zeta potential measurement, fluorescence microscopy, and antibody-mediated agglutination assay proved the recapitulation of RBC shape, size, and membrane structure. Flow-based deformation studies carried out in a microfluidic blood capillary model confirrned the ability of RRBCs to deform and pass through small slits and reconstitute themselves in a manner comparable to native RBCs. Circulation studies of RRBCs conducted ex-ovo in a chick embryo and in vivo in a mouse model demonstrated the requirement of both deformability and native cell membrane surface to achieve long-term circulation. To confer additional non-native functionalities to RRBCs, we developed modular procedures in which to load functional cargos such as hemoglobin, drugs, magnetic nanoparticles, and ATP biosensors within the RRBC interior to enable various functions, including oxygen delivery, therapeutic drug delivery, magnetic manipulation, and toxin biosensing and detection. Taken together, RRBCs represent a class of long circulating RBC-inspired artificial hybrid materials with a broad range of potential applications.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2020

Synthetic antiferromagnet-based spin Josephson oscillator

Two easy-plane ferromagnetic layers, antiferromagnetically coupled through a thin nonmagnetic metal layer, form the magnetic analog of a Josephson junction. Additionally, a current driven spin chemical potential drives a 2π precession of the in-plane magnetization of each ferromagnet. The participation of the full magnetic moment in the 2π precession maximizes the giant magnetoresistance and the ac output power. The frequency can be continuously tuned by a dc bias. An applied ac bias results in a time-averaged magnetoresistance with Shapiro-like steps. The multistate mode-locking behavior exhibited by the Shapiro steps may be exploited for applications such as microwave detectors and neuromorphic computing. They may also serve as an experimental signature of spin superfluidity.

42 ENGINEERING↗

DOE OSTI2025

Egg yolk as a model for gelation: From rheometry to flow physics

Egg yolks are an excellent model for studying sol-gel transitions, particularly the power law viscoelasticity that defines the critical point of gelation. However, prior studies lack comprehensive datasets and fail to visualize flow behavior linked to temperature and time-dependent linear and nonlinear rheology. Here, we present a detailed dataset characterizing egg yolk viscoelasticity across temperature, time, and forcing amplitude using oscillatory shear, step strain, step stress, and constant high strain rate. Novel protorheology visualizations link rheological properties with observable flow behavior. Our findings highlight the nuanced determination of the critical gel point, emphasizing observation timescale dependencies. We compare methods to identify critical temperatures for gelation, including power law viscoelasticity, moduli crossover, diverging zero-shear viscosity, and emerging equilibrium elastic modulus, while visualizing flow consequences near these transitions. Egg yolk is an accessible, realistic, and nontoxic material relevant to the physicist and the chef alike, making it ideal for understanding the rheology of critical gels. By integrating protorheology photos and videos with rigorous rheometric data, we deepen the understanding of critical gels, with broader impacts for studying other materials with sol-gel transitions.

Marsh, Maxwell C. [Department of Mechanical Scienc↗

DOE OSTI2025

High energy particle detection with large area superconducting microwire array

We present the first detailed study of an 8-channel2×2 mm$^{2}$ WSi superconducting microwire single photondetector (SMSPD) array exposed to 120 GeV proton beam and 8 GeVelectron and pion beam at the Fermilab Test Beam Facility. TheSMSPD detection efficiency was measured for the first time forprotons, electrons, and pions, enabled by the use of a silicontracking telescope that provided precise spatial resolution of30 μm for 120 GeV protons and 130 μm for 8 GeVelectrons and pions. The result demonstrated consistent detectionefficiency across pixels and at different bias currents. Timeresolution of 1.15 ns was measured for the first time for SMSPDwith proton, electron, and pions, enabled by the use of an MCP-PMTwhich provided a ps-level reference time stamp. The resultspresented is the first step towards developing SMSPD array systemsoptimized for high energy particle detection and identification forfuture accelerator-based experiments.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2021

In Situ Generation of High-Energy Spin-Polarized Electrons in a Beam-Driven Plasma Wakefield Accelerator

We report that in situ generation of a high-energy, high-current, spin-polarized electron beam is an outstanding scientific challenge to the development of plasma-based accelerators for high-energy colliders. In this Letter, we show how such a spin-polarized relativistic beam can be produced by ionization injection of electrons of certain atoms with a circularly polarized laser field into a beam-driven plasma wakefield accelerator, providing a much desired one-step solution to this challenge. Using time-dependent Schrödinger equation (TDSE) simulations, we show the propensity rule of spin-dependent ionization of xenon atoms can be reversed in the strong-field multiphoton regime compared with the non-adiabatic tunneling regime, leading to high total spin polarization. Furthermore, three-dimensional particle-in-cell simulations are incorporated with TDSE simulations, providing start-to-end simulations of spin-dependent strong-field ionization of xenon atoms and subsequent trapping, acceleration, and preservation of electron spin polarization in lithium plasma. We show the generation of a high-current (0.8 kA), ultralow-normalized-emittance (~ 37 nm ), and high-energy (2.7 GeV) electron beam within just 11 cm distance, with up to ~31% net spin polarization. Higher current, energy, and net spin-polarization beams are possible by optimizing this concept, thus solving a long-standing problem facing the development of plasma accelerators.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2020

Light regulation of light-harvesting antenna size substantially enhances photosynthetic efficiency and biomass yield in green algae

One of the major factors limiting biomass productivity in algae is the low thermodynamic efficiency of photosynthesis. The greatest thermodynamic inefficiencies in photosynthesis occur during the conversion of light into chemical energy. At full sunlight the light-harvesting antenna captures photons at a rate nearly 10 times faster than the rate-limiting step in photosynthetic electron transport. Excess captured energy is dissipated by non-productive pathways including the production of reactive oxygen species. Substantial improvements in photosynthetic efficiency have been achieved by reducing the optical cross-section of the light-harvesting antenna by selectively reducing chlorophyll b levels and peripheral light-harvesting complex subunits. Smaller light-harvesting antenna, however, may not exhibit optimal photosynthetic performance in low or fluctuating light environments. Additionally, we describe a translational control system to dynamically adjust light-harvesting antenna sizes for enhanced photosynthetic performance. Furthermore, by expressing a chlorophyllide a oxygenase (CAO) gene having a 5' mRNA extension encoding a Nab1 translational repressor binding site in a CAO knockout line it was possible to continuously alter chlorophyll b levels and correspondingly light-harvesting antenna sizes by light-activated Nab1 repression of CAO expression as a function of growth light intensity. Significantly, algae having light-regulated antenna sizes had substantially higher photosynthetic rates and two-fold greater biomass productivity than the parental wild-type strains as well as near wild-type ability to carry out state transitions and non-photochemical quenching. These results have broad implications for enhanced algae and plant biomass productivity.

09 BIOMASS FUELS↗

DOE OSTI2023

Hard x-ray – optical four-wave mixing using a split-and-delay line

New, hard x-ray free electron lasers (FEL) produce intense femtosecond-to-attosecond pulses at angstrom wavelengths, giving access to the fundamental spatial and temporal scales of matter. These revolutionary light sources open the door to applying the suite of nonlinear, optical spectroscopy methods at hard x-ray photon energies. Nonlinear spectroscopy with hard x-rays can allow for measuring the coherence properties of short wavelength excitations with atomic specificity and for understanding how high energy excitations couple to other degrees of freedom in atomic, molecular or condensed-phase systems. As a step in this direction, here we present hard x-ray, optical four-wave mixing (4WM) measurements done at 9.8 keV at the split-and-delay line at the x-ray correlation spectroscopy (XCS) hutch of the Linac Coherent Light Source (LCLS). In this work, we create an x-ray transient grating (TG) from a pair of crossing x-ray beams and diffract optical laser pulses at 400 nm from the TG. The key technical advance here is being able to independently vary the delays of the x-ray pulses. Measurements were made in 3 different solid samples: bismuth germinate (BGO), zinc oxide (ZnO) and yttrium aluminum garnet (YAG). The resulting phase-matched, 4WM signal is measured in two different ways: by varying the x-ray, x-ray pulse delay which can reveal both material and light source coherence properties and also by varying the optical laser delay with respect to the x-ray TG to study how the x-ray excitation couples to the optical properties. Although no coherent 4WM signal was seen in these measurements, the absence of this signal gives important information on experimental requirements for detecting this in future work. Also, our laser-delay scans, although not a new measurement, were applied to different materials than in past work and reveal new examples x-ray induced lattice dynamics in solids. This work represents a key step towards extending nonlinear optics and time-resolved spectroscopy into the hard x-ray regime.

47 OTHER INSTRUMENTATION↗

DOE OSTI2021

Low-Cost Aero Technology Demonstrations

The main focus of this work was to demonstrate the use of polymeric additive manufacturing (AM) to create tooling for both preforming and consolidation. Polymeric tooling was utilized where both modest and higher pressures are used for part consolidation. The key focus for the AM tooling development was for fabrication of complex structures such as ducting, C-channel stiffened skins, and airfoils where conventional male tooling would typically be trapped in the cured part. The AM tooling was evaluated for use as a tool master used to fabricate and re-shape deformable/re-formable mandrels based on SpinTech’s shape memory composite technology known as Smart Tooling. The AM tooling was also evaluated for use as a mold for composite infusion and consolidation. Key performance parameters were tracked for project schedule completion with each step comprising of “art to part” cycle time, cost, and model fidelity for dimensions, performance, and cost. The primary focus of this demonstration was to determine if a 50% cost reduction was achievable, for each AM tooling-set, as compared to conventional processes. UDRI leveraged project partner SpinTech, who manufactures tools and parts in these categories and thus provided a baseline regarding current best practices and provided valuable feedback during the entirety of this demonstration. This demonstration primarily focused on the use of AM tooling for fabrication of three composite component structures which are typically utilized in aircraft and comprise salient geometric features of broad interest. These components are often tooling intensive and have features requiring extraction of male tools which are usually trapped by the geometry. The three structures selected by the team included: 1) A one-piece airfoil shell comprised of compound contours where male tooling would be trapped unless the part were manufactured in two halves as is typically the case. 2) A one-piece duct used for air handling, comprised of compound contours where male tooling would be trapped unless the part were manufactured in two halves, or a washout mandrel were to be used. 3) A co-cured C-channel stiffened skin where typically C-channels would be individually manufactured and then bonded to a cured skin. The demonstration was comprised of three main tasks: • Task 1: AM Tool Feasibility Study – ensure the AM tooling meets the performance requirements as specified by SpinTech to match baseline performance. • Task 2: Complex Tool Demonstration – Fabricate tooling, preforms, and parts representative of an airfoil and duct. • Task 3: Large Aerostructure Fabrication Demonstration – Fabricate tooling, preforms, and part representative of a C-channel stiffened skin. With the conclusion of this project, a decision tree was developed to determine the key considerations necessary to determine if use of AM tooling for the three selected structures was able to attain the same quality as historically achieved on metallic tooling, while providing a significant cost reduction.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Operando X-ray Nanocharacterization of Polycrystalline Thin Film Modules

Non-destructive measurement techniques, with high spatial resolution, capable of correlating composition and structure with device properties, are few and far between. For the case of polycrystalline and inhomogeneous materials, the added challenge is that large sampling areas are necessary in order to have a statistical representation of the specimen under study. For the study of grain cores and grain boundaries in polycrystalline solar absorbers this is of particular importance since their dissimilar behavior and variability throughout the samples makes it difficult to draw conclusions and ultimately optimize the materials and devices. Our approach to use state-of-the-art x-ray microscopy to study full module stacks under operating conditions is unique. Understanding the effects of elemental and charge migration under full encapsulation and operating conditions will allow CIGS and CdTe manufactures and in particular our partners in this proposal to modify materials, stacks, architectures, and processing steps to minimize the performance losses through time.

14 SOLAR ENERGY↗

DOE OSTI2026

Two 28-nm front-end ASICs for ultra-fine spatial resolution and precision timing to be 3D integrated with 12 LGADs

The 3DIntSenS Collaboration—a joint effort between SLAC, Fermilab, and LLNL—is developing enabling technologies for next-generation radiation imaging detectors that combine ultra-fine spatial resolution (about 10 µm) with precision timing (<20 ps), while maintaining low power <1 W/cm2 and high data throughput. The approach leverages 3D integration between advanced CMOS readout ASICs and finely pixelated LGAD sensors to achieve the performance and scalability required for large-area, high-rate applications. High-granularity, precision-timing detectors are essential for scientific advances in HEP, NP, BES, and FES, but widespread adoption is limited by the cost and complexity of 3D integration. To close this gap, the collaboration is developing LGAD sensors compatible with 12-inch commercial CMOS processes, enabling cost-effective integration with high-performance ASICs under development. We present two 28 nm CMOS ASIC prototypes, including a low-jitter front end, and in-pixel TDC demonstrating sub-10 ps timing resolution. These advances represent a critical step toward scalable, high-resolution radiation imaging systems for future scientific instrumentation.

England, Troy [Fermilab] (ORCID:0000000154405255)↗

DOE OSTI2026

Two 28-nm front-end ASICs for ultra-fine spatial resolution and precision timing to be 3D integrated with 12 LGADs

England, Troy [Fermilab] (ORCID:0000000154405255)↗

DOE OSTI2024

Scalable, Infiltration-Free Ceramic Matrix Composite Manufacturing

Manufacturing of ceramic matrix composites (CMCs) with carbon fiber and carbon matrix includes a time- and labor-intensive ceramic infiltration step that is responsible for more than half of the total manufacturing cost. To make CMCs cost-competitive in price-sensitive markets, like concentrated solar power, it is essential to develop a CMC manufacturing process that skips the ceramic infiltration process. In this work, we will show how a high-char-yield preceramic resin can eliminate the infiltration step while maintaining material density and evaluate the technoeconomic impact of our CMC manufacturing process. We monitor both morphology and porosity to determine the quality of CMCs made with different preceramic resins and evaluate the impact of polymer infiltration and pyrolyzing cycles.

matrix composite, polymer infiltration and pyrolys↗

DOE OSTI2024

Simplified, Infiltration-free Ceramic Matrix Composite Manufacturing

Manufacturing of ceramic matrix composites (CMCs) with carbon fiber and carbon matrix includes a time- and labor-intensive ceramic infiltration step that is responsible for more than half of the total manufacturing cost. To make CMCs cost-competitive in price-sensitive markets, like concentrated solar power, it is essential to develop a CMC manufacturing process that skips the ceramic infiltration process. In this work, we will show how a high-char-yield preceramic resin can eliminate the infiltration step while maintaining material density and evaluate the technoeconomic impact of our CMC manufacturing process. Here, we monitor both morphology and porosity to determine the quality of CMCs made with different preceramic resins and evaluate the impact of polymer infiltration and pyrolyzing cycles.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Foil deposition onto an additive manufactured substrate

An additive manufacturing system and method for forming a part of dissimilar materials. The additive manufacturing system may include a build platform, a recoater for dispensing build powder onto the build platform, an energy source, a foil feed assembly, and a controller for controlling actuation of these components. The method of forming the part may include the steps of depositing a layer of build powder onto the build platform surface, melting selected portions of the layer of build powder, applying a sheet of foil over the layer of build powder, melting selected portions of the sheet of foil onto the layer of build powder, removing the sheet of foil from the layer of build powder, and then lowering the build platform surface to prepare for deposition of a next layer of the build powder. These steps are then repeated one or more times, thereby forming the part.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Fast formation cycling for rechargeable batteries

A method for fast formation cycling for rechargeable batteries comprising the steps of: step 1 (First Partial Charge)—charge cell from open-circuit voltage (OVC) up to 80-90% of an upper cutoff voltage (UCV) of from 4-5 V at a C rate not less than 0.5 and not more than 1.5; step 2 (First Shallow Charge)—charge cell from 80-90% of UCV to 97-100% of UCV at a C rate of not less than 0.2 and not more than 0.5; step 3 (First Shallow Discharge)—discharge cell from 97-100% of UCV to 80-90% of UCV at a C rate of not less than 0.2 and not more than 0.5; and step 4 (Subsequent Charge/Discharge Cycles)—repeat steps 2-3 up to 2-10 times where the charging and discharging rates are progressively increased by 25-75%. A battery made according to the method of the invention is also disclosed.

Wood, III, David L.↗