SEARCH · Engineering Papers

Results for “CAT”

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.

72 records · Page 4

All sources NASA NTRS DOE OSTI

DOE OSTI2026

Active site design enables industrial scale H 2 O 2 electrosynthesis with metal-free catalysts

The electrosynthesis of hydrogen peroxide (H 2 O 2 ) via a two-electron oxygen reduction reaction enables decentralized H 2 O 2 production. While metal-free carbon catalysts are sustainable and low-cost, their performance is hindered by poorly defined active sites and uncontrolled defect states. Here, we resolve these challenges through active site design and catalyst screening using fluorine (F) and nitrogen (N) codoped carbons as model materials. Statistical analysis combined with density functional theoretical calculations reveals that F-induced structural modification and defect passivation optimize OOH* binding, with F-doping and adjacent F atoms predominantly lowering abs ΔG(OOH*). Experimental results confirm that semi-ionic C–F bonds passivate defects in nitrogen-doped carbon, enhancing catalytic activity and durability. The resulting (N, F)-codoped carbon achieves nearly 100% H 2 O 2 selectivity at 0.5–0.65 V versus the reversible hydrogen electrode and maintains > 95% across 0.01–0.65 V versus the reversible hydrogen electrode. In an electrolyzer, (N, F)-codoped carbon exhibits an H 2 O 2 yield rate of 74.35 mol g cat. −1 h -1 and sustains 300 mA cm -2 for 105 hours with ~95% faradaic efficiency. Coupling the two-electron oxygen reduction reaction with methanol oxidation further reduces cell voltage and enhances productivity. This work provides a means to design efficient catalysts for industrial H 2 O 2 electrosynthesis.

H2O2 electrosynthesis↗

DOE OSTI2024

A driven Kerr oscillator with two-fold degeneracies for qubit protection

We present the experimental finding of multiple simultaneous two-fold degeneracies in the spectrum of a Kerr oscillator subjected to a squeezing drive. This squeezing drive resulting from a three-wave mixing process, in combination with the Kerr interaction, creates an effective static two-well potential in the phase space rotating at half the frequency of the sinusoidal drive generating the squeezing. Remarkably, these degeneracies can be turned on-and-off on demand, as well as their number by simply adjusting the frequency of the squeezing drive. We find that when the detuning Δ between the frequency of the oscillator and the second subharmonic of the drive equals an even multiple of the Kerr coefficient K , Δ / K = 2 m , the oscillator displays m + 1 exact, parity-protected, spectral degeneracies, insensitive to the drive amplitude. These degeneracies can be explained by the unusual destructive interference of tunnel paths in the classically forbidden region of the double well static effective potential that models our experiment. Exploiting this interference, we measure a peaked enhancement of the incoherent well-switching lifetime, thus creating a protected cat qubit in the ground state manifold of our oscillator. Our results illustrate the relationship between degeneracies and noise protection in a driven quantum system.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2026

Higher-Form Anomalies on Lattices

We show that generic gapped quantum many-body states which respect an anomalous finite higher-form symmetry have an exponentially small overlap with any short-range entangled (SRE) state. Hence, anomalies of higher-form symmetries enforce $intrinsic$ long-range entanglement, which is in contrast with anomalies of ordinary (0-form) symmetries which are compatible with symmetric SRE states (specifically, symmetric cat states). As an application, we show that the anomalies of strong higher-form symmetries provide a diagnostic for mixed-state topological order in $d \geq 2$ spatial dimensions. We also identify a new (3+1)D intrinsic mixed-state topological order that does not obey remote-detectability by local decoherence of the (3+1)D Toric Code with fermionic loop excitations. This breakdown of remote detectability, as encoded in anomalies of strong higher-form symmetries, provides a partial characterization of intrinsically mixed-state topological order.

Feng, Yitao [Peking University, Beijing (China)] (↗

DOE OSTI2024

Crosstalk-robust quantum control in multimode bosonic systems

High-coherence superconducting cavities offer a hardware-efficient platform for quantum information processing. To achieve universal operations of these bosonic modes, the requisite nonlinearity is realized by coupling them to a transmon ancilla. However, this configuration is susceptible to crosstalk errors in the dispersive regime, where the ancilla frequency is Stark shifted by the state of each coupled bosonic mode. This leads to a frequency mismatch of the ancilla drive, lowering the gate fidelities. To mitigate such coherent errors, we employ quantum optimal control to engineer ancilla pulses that are robust to the frequency shifts. These optimized pulses are subsequently integrated into a recently developed echoed conditional displacement protocol for executing single- and two-mode operations. Through numerical simulations, we examine two representative scenarios: the preparation of single-mode Fock states in the presence of spectator modes and the generation of two-mode entangled Bell-cat states. Our approach markedly suppresses crosstalk errors, outperforming conventional ancilla control methods by orders of magnitude. These results provide guidance for experimentally achieving high-fidelity multimode operations and pave the way for developing high-performance bosonic quantum information processors.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2024

Elliptically-Contoured Tensor-variate Distributions with Application to Image Learning

Statistical analysis of tensor-valued data has largely used the tensor-variate normal (TVN) distribution that may be inadequate for data arising from distributions with heavier or lighter tails. We study a general family of elliptically contoured (EC) TV distributions and derive its characterizations, moments, marginal, and conditional distributions. We describe procedures for maximum likelihood estimation from data that are (1) uncorrelated draws from an EC distribution, (2) from a scale mixture of the TVN distribution, and (3) from an underlying but unknown EC distribution, for which we extend Tyler’s robust estimator. A detailed simulation study highlights the benefits of choosing an EC distribution over the TVN for heavier-tailed data. We develop TV classification rules using discriminant analysis and EC errors and show that they better predict cats and dogs from images in the Animal Faces-HQ dataset than the TVN-based rules. A novel tensor-on-tensor regression and TV analysis of variance (TANOVA) framework under EC errors is also demonstrated to better characterize gender, age, and ethnic origin than the usual TVN-based TANOVA in the celebrated labeled faces of the wild dataset.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2024

Insights into Designing an Efficient and Reliable Microwave-Assisted Methane Dehydroaromatization Process: Effect of Microwave Absorber on Catalyst Performance

Microwave-assisted methane dehydroaromatization has the potential to address challenges of traditional dehydroaromatization reactions. However, catalysts for microwave-enhanced reaction systems require effective coupling of fields with the catalyst to produce heat and reach reaction temperatures. Here, this work presents an in-depth understanding of the effect of the addition of silicon carbide as a microwave absorber on catalyst performance among other variables, the viability of the microwave reactor configuration, and insights into designing an effective and reliable microwave-based methane dehydroaromatization process. The effect of other parameters including temperature, weight hourly space velocity, role of microwave absorber, and methane concentration during microwave-assisted methane dehydroaromatization reaction are studied. Mo/ZSM-5 was found to suffer from low permittivity and nonuniform heating under microwave conditions. Mixing silicon carbide powder as a microwave absorber with the catalyst was found to provide more uniform heating. When assessing the catalytic performance of the mixture, it was found that higher methane partial pressures at 2000 cc/g cat .h and a temperature range of 500-600°C produced the highest amount of benzene. The formation of graphitic carbon on the spent catalyst increased with temperature, gas-solid contact period, and methane concentration, which resulted in higher methane conversion and benzene selectivity. The study indicates that under microwave heating the presence of localized carbon enhanced catalyst life by coupling with microwave energy, leading to localized heating, and improving benzene selectivity.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2026

AmeriFlux FLUXNET-1F MX-PMm Puerto Morelos mangrove

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site MX-PMm Puerto Morelos mangrove. This is the FLUXNET version of the carbon flux data for the site MX-PMm Puerto Morelos mangrove produced by applying the standard ONEFlux (1F) software. Site Description - The tower was located at the “Dr. Alfredo Barrera Marín” Botanical Garden. The surface monitored is covered with basin mangrove (sporadically flooded wetland) that grows in a fringe parallel to the northeastern coast (ca. 1 km) of the Yucatan Peninsula. The dominant species are Rhizophora mangle and Conocarpus erectus, which grow intertwined and relatively stunted (max tree height is 5m). Under the influence of trade winds and frequent stroms. The vegetation is regenerating after complete defoliation due to hurricane Wilma (cat. 4) passing in October 2005. The site is sporadically flooded by rainfall soil saturation excess; there are no marine surface water inputs but ground water level fluctuations show tidal signals. The terrain of the monitored surface is flat, while the area downwind of the tower presents a slope which corresponds to an ancient coast line. There is extensive urban development in the coastal dune along the coast mainly for tourism use (Mayan Riviera).

Alvarado-Barrientos, Ma. Susana [Instituto de Ecol↗

DOE OSTI2024

Synergistic Thermo-Microbial-Electrochemical (T-MEC) Approach for Drop-In Fuel Production from Wet Waste

This project successfully developed and demonstrated the synergistic thermo-microbial-electrochemical (T-MEC) process, converting food waste into sustainable biofuels while achieving self-sustaining wastewater treatment and hydrogen production. By integrating hydrothermal liquefaction (HTL) and microbial electrolysis cells (MECs), the project advanced waste-to-fuel technology and expanded the understanding of sustainable waste valorization. It established a scalable framework for achieving high carbon efficiency, effective pollutant removal, and energy recovery, showcasing the potential of combining biological, thermal, and electrochemical systems to optimize resource recovery and reduce environmental impacts. The project demonstrated the technical effectiveness of the T-MEC process, achieving over 50% improvement in carbon efficiency and reducing waste processing costs by more than 25% compared to anaerobic digestion (AD). The HTL pilot reactor processed food waste at 90 kg/h, producing up to 200 L/day of biocrude oil with high conversion efficiency. A critical desalting step in pretreatment prevented catalyst fouling, enabling efficient hydrotreating with 100% deoxygenation and denitrogenation and sulfur reduction to <15 ppm. This positioned the kerosene fraction as a strong candidate for sustainable aviation fuel (SAF). The MECs achieved rapid startup, 86.4% COD removal, and hydrogen production rates of 1.8 L H 2 /L cat /day, among the highest recorded for pilot-scale systems. The integrated process achieved 65% carbon efficiency to biocrude and 58% to finished fuels, outperforming AD's 41% and 33% efficiencies for biogas and natural gas vehicle fuels. System analysis highlighted economic potential, with minimum fuel selling prices (MFSP) decreasing from $\$$25/GGE at 5 tpd to $\$$10/GGE at 500 tpd due to economies of scale. Future work will focus on reducing MEC material and membrane costs, enhancing performance through higher current densities, and creating tailored operational strategies for diverse feedstocks. Optimization of the integrated system will improve scalability and feasibility, positioning the T-MEC process as a competitive solution for converting wet waste into sustainable fuels and clean water. Beyond its technical and economic achievements, the project offers significant public benefits. The T-MEC process provides a sustainable alternative to landfilling and incineration, reducing greenhouse gas emissions and conserving resources. Converting waste into SAF and renewable fuels supports decarbonization in the transportation sector, advancing energy independence and reducing reliance on fossil fuels. Additionally, the process minimizes environmental pollutants, transforming them into valuable products like hydrogen and fuels, contributing to a cleaner and more sustainable future.

09 BIOMASS FUELS↗

DOE OSTI2025

Semiconductor‐Electrocatalyst Contacts: Theory, Experiment, and Applications to Solar Water Photoelectrolysis

The goal of the work supported by this program was to use new types of photoelectrochemical experiments, supported by simulation and theory, to develop an improved microscopic picture of electron transfer in combined semiconductor|catalyst|solution (sem|cat|sol) systems. An emphasis was placed on developing techniques which can directly characterize electronic interfacial phenomena without first assuming a junction model. We then aimed to illustrate the design principles that enhance interfacial processes and enable high-efficiency devices. Our work thus provides deep insight into the processes that, in general, use light to drive chemical reactions.

14 SOLAR ENERGY↗

DOE OSTI2025

Hybrid Quantum Networks with Discrete Polarizations and Continuous Quadrature Variables

Final Scientific/Technical Report for DOE Project DE-SC0022069. Quantum communication and computation systems have evolved along two largely independent paradigms: discrete-variable (DV) systems that encode information in qubits such as photon polarizations or photon-number states, and continuous-variable (CV) systems that encode information in optical field quadratures. Each approach offers distinct advantages—DVs provide low error rates and compatibility with single-photon platforms, while CVs support deterministic operations and efficient quantum state manipulation. A fundamental challenge for building a scalable Quantum Internet lies in interfacing these two regimes into a unified hybrid architecture that can coherently distribute and process quantum information across heterogeneous quantum nodes. This project aims to develop and demonstrate a hybrid optical quantum network that seamlessly integrates DV and CV systems. Specifically, we investigate a new class of hybrid entanglement between the discrete polarizations of single photons and the continuous quadrature variables of optical cat states, overcoming incompatibilities in existing DV–CV demonstrations. Using this new entanglement resource, the team investigates a multi-node hybrid quantum local area network (Q-LAN) testbed capable of DV–CV entanglement generation, swapping, and distribution across fiber links.

74 ATOMIC AND MOLECULAR PHYSICS↗

DOE OSTI2025

Corral Summit Pumped Storage Hydropower Hybrid: Site Suitability Assessment

In 2024, Idaho National Laboratory (INL) and Pacific Northwest National Laboratory (PNNL) initiated a technical-assistance project to support Cat Creek Energy, LLC, (CCE) in evaluating site suitability for the proposed Corral Summit Pumped Storage Hydropower (PSH) project in south-central Idaho near Mackay Reservoir. The Corral Summit facility incorporates battery storage and photovoltaic (PV) solar arrays in a Trybrid configuration to deliver large-volume long-duration (LVLD) storage solutions for rural electric cooperatives in eastern Idaho. The evaluation process focused on determining the most-suitable location for the upper reservoir of the PSH system, guided by a comprehensive assessment framework spanning multiple categories, including physical characteristics, environmental constraints, building infrastructure, regulatory constraints, cultural resources and sensitivity, social factors, and power market and grid integration. Each site was analyzed based on a ranking scale (0–1), which scores ranging from “severely disfavored” to “highly favored,” allowing detailed comparisons of site-specific conditions. Categories such as hydraulic head, utilities corridor, land ownership, and transmission-grid limitations emerged as key contributors to the overall assessment. Site 2 (Idaho Trust) demonstrated a slight advantage over Site 1 (Bureau of Land Management) primarily due to favorable outcomes in regulatory constraints, building infrastructure, and power-market integration. However, Site 1 outperformed Site 2 in factors related to physical characteristics and social factors. The report emphasizes the need for further evaluation of both sites before clear determination of which site is preferred, due to the limited information available on either site at the time of this report. Key areas of evaluation to clearly define the preferred site are ecological impacts, cultural-resource surveys, and economic-feasibility assessments. For successful project execution, recommended follow-up actions include seismic and geotechnical surveys, groundwater and habitat monitoring, regulatory reviews of water rights and right-of-way agreements, cultural engagement with local tribal governments, and enhanced stakeholder strategies. These efforts will ensure the Corral Summit Trybrid facility meets local energy needs while balancing environmental, social, and regulatory responsibilities.

13 - HYDRO ENERGY↗

DOE OSTI2025

Hybridization Assessment of Trybrid Pumped Storage Hydropower System—Part 1: A Case Study of Corral Summit

This report is a part of the deliverables for technical assistance provided to Cat Creek Energy for the Coral Summit Trybrid (Triple Hybrid-Pumped Storage Hydropower, Battery Energy Storage System, and photovoltaic solar energy) energy project. This report explores the operational benefits and challenges of hybridizing an open loop PSH (200MW) located at Mackay, Custer County, Idaho with solar PV (Ground mount 300MW and floating 40MW) and battery (720MWhr). This document reports two activities performed as a part of the hybridization assessment task 1) optimal resource allocation and energy management strategy, and 2) power quality and reliability assessment. From optimal resource allocation and energy management strategy (activity 1), the following key findings can be observed: • Conventional PSH (CPSH) with two reversible pump turbines and separate penstocks can provide required flexibility equivalent to that from two ternary PSH with separate penstock. With single unit CPSH, upper reservoir head cannot be maintained accurately, the variation of water level is rapid and pump mode flexibility is not available. These disadvantages can be overcome by single unit TPSH. However, using two CPSH units with separate penstocks also overcome these disadvantages with the formation of the hydraulic short circuit between two conventional units. • Flooding of the lower reservoir is a severe concern when considering continuous operation for black start. This limits the duration of continuous operation from PSH alone to around 50 hours. Due to the complementary PV and battery action, the duration of continuous operation and smooth power output can be extended. • An optimization problem is framed that maximizes the power output on an hourly basis while minimizing constraint violations and respecting seasonal variations of solar PV and load profiles . Two value streams, arbitrage and baseload generation are served by this profile. It was uncovered that for smooth power output during regular operation, PV curtailment will be required, or the battery capacity needs to be increased above 90MW to accommodate additional PV. From power quality and reliability assessment (activity 2) the following takeaway points can be observed: • The Trybrid, when integrated at the Lost River bus, and limited to 250MW in generation mode and -150MW in the pump mode, causes no violation of voltage or flow.

13 - HYDRO ENERGY↗

DOE OSTI2025

Corral Summit Pumped Storage Hydropower Hybrid Site Suitability Assessment (Rev.1)

13 - HYDRO ENERGY↗

DOE OSTI2024

N α -acetyl-L-ornithine deacetylase from Escherichia coli and a ninhydrin-based assay to enable inhibitor identification

Bacteria are becoming increasingly resistant to antibiotics, therefore there is an urgent need for new classes of antibiotics to fight antibiotic resistance. Mammals do not express N α -acetyl-L-ornithine deacetylase (ArgE), an enzyme that is critical for bacterial survival and growth, thus ArgE represents a promising new antibiotic drug target, as inhibitors would not suffer from mechanism-based toxicity. A new ninhydrin-based assay was designed and validated that included the synthesis of the substrate analog N 5 , N 5 -di-methyl N α -acetyl-L-ornithine (k cat /K m = 7.32 ± 0.94 × 10 4 M -1 s -1 ). This new assay enabled the screening of potential inhibitors that absorb in the UV region, and thus is superior to the established 214 nm assay. Using this new ninhydrin-based assay, captopril was confirmed as an ArgE inhibitor (IC 50 = 58.7 μM; K i = 37.1 ± 0.85 μM), and a number of phenylboronic acid derivatives were identified as inhibitors, including 4-(diethylamino)phenylboronic acid (IC 50 = 50.1 μM). Selected inhibitors were also tested in a thermal shift assay with ArgE using SYPRO Orange dye against Escherichia coli ArgE to observe the stability of the enzyme in the presence of inhibitors (captopril K i = 35.9 ± 5.1 μM). The active site structure of di-Zn Ec ArgE was confirmed using X-ray absorption spectroscopy, and we reported two X-ray crystal structures of E. coli ArgE. In summary, we describe the development of a new ninhydrin-based assay for ArgE, the identification of captopril and phenylboronic acids as ArgE inhibitors, thermal shift studies with ArgE + captopril, and the first two published crystal structures of ArgE (mono-Zn and di-Zn).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2025

Approach for High Methanol Substitution by Energy with Conventional and Bio Pilot Fuels

Green methanol is emerging as a promising route to decarbonize the commercial marine industry. However, methanol is not a drop-in fuel in the compression ignition engines that dominate the marine industry because it is difficult to ignite due to its low cetane number and high latent heat of vaporization. The most straight-forward way to use methanol in the compression ignition engines is to premix the methanol, such as with port fuel injection during the intake stroke, and igniting the methanol with a diesel pilot injection. Because diesel fuel is still used in this strategy, it does not fully displace the petroleum diesel fuel. To completely displace the petroleum-derived diesel fuel, this investigation presents experimental results comparing diesel and biodiesel pilot ignition in a dual-fuel strategy with methanol in a marine-variant of a Cat® C18 18 L engine with a 145 mm bore. Engine performance and emissions characteristics are presented that include effects of diesel vs. biodiesel across a series of fuel injection timing and other operating parameters, including intake manifold pressure and engine load. Results presented include in-cylinder pressure and combustion-related findings about heat release, methanol fuel energy substitution rates greater than 75% from 1 to 18 bar BMEP on a single cylinder engine at 1800 RPM. Criteria pollutants including particulate matter, NOx (NO and NO2), unburned fuel, and formaldehyde, as well as the overall BSFC and FSN of the combustion process relative to the baseline diesel operation.

Splitter, Derek [ORNL] (ORCID:0000000174044047)↗

DOE OSTI2025

Mechanical and Light Activation of Materials for Chemical Production

Abstract Mechanical expansion and contraction of pores within photosynthetic organisms regulate a series of processes that are necessary to manage light absorption, control gas exchange, and regulate water loss. These pores, known as stoma, allow the plant to maximize photosynthetic output depending on environmental conditions such as light intensity, humidity, and temperature by actively changing the size of the stomal opening. Despite advances in artificial photosynthetic systems, little is known about the effect of such mechanical actuation in synthetic materials where chemical reactions occur. It is reported here on a hybrid hydrogel that combines light‐activated supramolecular polymers for superoxide production with thermal mechanical actuation of a covalent polymer. Superoxide production is important in organic synthesis and environmental remediation, and is a potential precursor to hydrogen peroxide liquid fuel. It is shown that the closing of pores in the hybrid hydrogel results in a substantial decrease in photocatalysis, but cycles of swollen and contracted states enhance photocatalysis. The observations motivate the development of biomimetic photosynthetic materials that integrate large scale motion and chemical reactions.

Đorđević, Luka [Department of Chemical Sciences Un↗

DOE OSTI2025

Fourier-based three-dimensional multistage transformer for aberration correction in multicellular specimens

High-resolution tissue imaging is often compromised by sample-induced optical aberrations that degrade resolution and contrast. Although wavefront sensor-based adaptive optics (AO) can measure these aberrations, such hardware solutions are typically complex, expensive to implement and slow when serially mapping spatially varying aberrations across large fields of view. Here we introduce AOViFT (adaptive optical vision Fourier transformer)—a machine learning-based aberration sensing framework built around a three-dimensional multistage vision transformer that operates on Fourier domain embeddings. AOViFT infers aberrations and restores diffraction-limited performance in puncta-labeled specimens with substantially reduced computational cost, training time and memory footprint compared to conventional architectures or real-space networks. We validated AOViFT on live gene-edited zebrafish embryos, demonstrating its ability to correct spatially varying aberrations using either a deformable mirror or postacquisition deconvolution. By eliminating the need for the guide star and wavefront sensing hardware and simplifying the experimental workflow, AOViFT lowers technical barriers for high-resolution volumetric microscopy across diverse biological samples.

Alshaabi, Thayer [Howard Hughes Medical Institute,↗

DOE OSTI2026

The biogeography of soil and airborne fungi in the Southwestern USA in relation to climate and vegetation

To assess how fungal dispersal might respond to climate change, we examined how climate and geography influence the regional distribution of fungi in soil and air. Specifically, we hypothesized that neighboring fungal communities should be more similar than distant communities (i.e. spatially autocorrelated) and that fungal dispersal should be more limited in soil than in air. We collected soil and air samples from 60 sites across five states in the Southwestern USA. Then, we sequenced the ITS2 region to identify fungal taxa in each sample. Next, we used distance-based redundancy analysis to partition variation in fungal community composition between climate variables and spatial structure. Fungi were indeed spatially autocorrelated. Moreover, precipitation, maximum vapor pressure deficit, and soil moisture were significantly related to fungal community composition in soils. In comparison, only precipitation was significantly related to community composition in the air. After accounting for climate, the strength of spatial autocorrelation did not differ significantly in soilborne versus airborne fungi. Dispersal limitation was evident in soilborne fungi at short distances (<100 km) and was not observed at any distance in airborne fungi. Altogether, climate may influence which fungal taxa are present in soil and air, and fungi could feasibly wind disperse over regional scales.

54 ENVIRONMENTAL SCIENCES↗