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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 1,459 records · Page 81
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

First-principles elucidation of the effects of Al-doping on Li-ion diffusion in LiCoO 2

Al-doped garnet Li 7 La 3 Zr 2 O 12 solid-electrolyte and LiCoO 2 cathode are promising choices as catholyte materials in all solid-state Li batteries, however, interdiffusion of Al is commonly evident during high-temperature processing and electrochemical cycling. Furthermore, to address the impact of Al interdiffusion on Li + transport properties in LiCoO 2 , we carried out a systematic evaluation of Al doping on Li + diffusion barriers in LiCoO 2 using first-principles based methods. Following the monovacancy diffusion mechanism, Al-doping (primarily at the Co site) is found to improve Li diffusion kinetics in the LiCoO 2 lattice due to favorable CoO 6 octahedral distortion experienced at the transition states. However, when considering the previously established dominant divacancy diffusion mechanism, slower Li diffusion is generally expected. In addition, a broad variation of Li diffusion barriers is observed upon Al doping, which suggests the system may suffer from non-uniform Li incorporation and diffusion that adversely affects its rate capacity during cycling. In summary, this work highlights, for the rational design of catholyte of all solid-state batteries, special attention may need to be paid to address the potential impact of non-intentional doping induced during processing on the overall electrochemical performance of the catholyte.

Al-doped LiCoO2↗
DOE OSTI2023

Exploring the interfacial structure and crystallinity for direct growth of Mn 3 Sn(0001) on sapphire (0001) by molecular beam epitaxy

The Kagome antiferromagnet Mn 3 Sn has garnered a lot of attention due to the presence of interesting properties such as anomalous Hall effects and Nernst effects. Until now, few papers have been reported to grow using molecular beam epitaxy with a buffer layer or on other substrates. In this paper, we discuss the synthesis of crystalline Mn 3 Sn layers, prepared on Al 2 O 3 (0001) without a buffer layer using molecular beam epitaxy. The growth is monitored in-situ using reflection high energy electron diffraction and measured ex-situ using X-ray diffraction, Rutherford back-scattering, and cross-sectional scanning transmission electron microscopy. The samples were deposited at 524 ± 5 °C, with an Mn: Sn atomic flux ratio of 3.2:1 for 90 minutes. Orientation relationships between the Mn 3 Sn films and the sapphire substrates are determined from in-plane and out-of-plane measurements. Our analysis indicates that the resulting film is predominantly c−plane oriented. Lastly, the samples prepared in this way were found to be discontiguous, showing a 3-dimensional morphology. According to first-principles calculations, the Mn 3 Sn exhibits a displaced Kagome structure in the very first stages of growth, for 2ML and 4ML growth on Al 2 O 3 (0001). This result is corroborated by calculating the surface formation energies and explains the observed RHEED patterns.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Analytical advances to study the air – water interfacial chemistry in the atmosphere

Formation of aqueous secondary organic aerosol (aqSOA) at the air – liquid interface recently has attracted a lot of attention in atmospheric chemistry. The discrepancies in mass distributions, aerosol oxidative capacity, liquid water content, hygroscopic growth of aerosols, and formation of clouds and fogs suggest that interfacial chemistry play a more important role than previously deemed. However, detailed mechanisms at the air–water interface remain unclear owing to the lack of comprehensive understanding that underpins complicated interfacial phenomena, which are not easily measurable from field campaigns, laboratory measurements, or computational simulations. Here, this review highlights relevant and recent technical advancement employed to study aqSOA encompassing spectroscopy and mass spectrometry. The current knowledge on the aqSOA processes is digested with an emphasis on recent research of interfacial aqSOA formation including laboratory studies and model simulations. Finally, future directions of the interfacial chemistry are recommended for field and laboratory studies as well as theoretical efforts to resolve interfacial challenges in atmospheric chemistry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Challenges in the post-licensing stage of U.S. hydropower development: Current status and some potential solutions

The issuance of a Federal Energy Regulatory Commission (FERC) license is an important milestone in the development process of new U.S. hydropower projects. The complexity and uncertain timeline of the licensing process have been often cited as a key deterrent to new hydropower installations in the United States. However, very little attention has been paid to post-licensing timelines and attrition rates. This article explores the challenges faced by developers in bringing their FERC-licensed hydropower projects to the construction stage. Post-licensing activities to be completed before starting construction include obtaining additional permitting from other federal or state agencies, completing the technical design, securing financing, and in most cases, negotiating a power purchase agreement. For the set of projects that obtained a FERC license between 2007 and 2018, we assembled a dataset—combining information from FERC dockets and responses from a questionnaire to developers—to calculate attrition rates and development timelines and to examine the reasons for delays and cancellations.

13 HYDRO ENERGY↗
DOE OSTI2021

Adoption of delivery services in light of the COVID pandemic: Who and how long?

A significant growth in demand for online shopping in light of the Coronavirus Disease (COVID) crisis has received attention from transportation practitioners, policy-makers, and researchers. However, an important question arises in this increase in online shopping and resulting deliveries: How long will this last? Very little is known whether this popularity would last a long time. Here, to address this question, the authors conducted a survey of 915 individuals residing in the U.S. and classified them into the four distinctive consumer types (i.e., the prior adopter, temporary adopter and permanent new adopter, and non-adopter) depending on their usage of delivery services before, during, and after (expected) the COVID crisis. This research aims to gain behavioral insight by exploring the differences between the four consumer types and investigating factors affecting the initial adoption and continuance intention of using delivery services. The descriptive analysis revealed that there are clear differences not only between the four types of consumers but also between the four product types (i.e., grocery, food, home goods, and other packages) considered in the survey. The models found that factors affecting the initial adoption and continuance intention are different from the previous studies conducted before the COVID pandemic. Implications for planning and policymaking are also discussed.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2023

Online detection of airborne nanoparticle composition with mass spectrometry: Recent advances, challenges, and opportunities

Airborne nanoparticles are receiving growing attention due to their impacts on human health, air quality, and climate. Additionally, there are increasing applications of aerosol-based nanotechnology. Real-time measurement of airborne nanoparticle composition is challenging due to their small masses and the difficulties in effectively separating them from larger particles. Custom-built instruments based on mass spectrometry have been developed for nanoparticle composition, including thermal desorption-based, laser-based, and solution-based techniques. They have significantly promoted the understanding of airborne nanoparticles in the last two decades. However, they are affected by molecular fragmentation, lack of mass-resolving power, incomplete species detection, and difficulties in directly comparing to gas-phase measurements. Recent developments in atmospheric mass spectrometry provide possible solutions. Here, this review presents the potential application of these new advances to real-time measurements of the molecular nanoparticle composition and discusses the associated challenges. Such measurements present opportunities for a more comprehensive view of airborne nanoparticles and their impacts.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Formulation and solution approach for calibrating activity-based travel demand model-system via microsimulation

This study addresses the problem of calibrating utility-maximizing nested logit activity-based travel demand model-systems. After estimation, it is common practice to use aggregate measurements to calibrate the estimated model-system’s parameters prior to their application in transportation planning, policy making, and operations. However, calibration of activity-based model-systems has received much less attention. Existing calibration approaches are myopic heuristics in the sense that they do not consider the fundamental inter-dependencies among choice-models and do not have a systematic way to adjust model parameters. Also, other purely simulation-based approaches do not perform well in large-scale applications. In this study, we focus on utility-maximizing nested logit activity-based model-systems and calibrating aggregate statistics such as activity shares, mode shares, time-dependent & mode-specific OD flows, and time-dependent & mode-specific sensor counts. We formulate the calibration problem as a simulation-based optimization problem and propose a stochastic gradient-based solution procedure to solve it. The solution procedure relies on microsimulation to calculate expectations of the aggregate statistics of interest to the calibration problem. Additionally, we derive approximate analytical expressions for the gradient of the objective function —that are evaluated through microsimulation on mini-batches of the population. The proposed solution procedure is sensitive to the fundamental structure of the activity-based model-system and is non-myopic in considering the dependencies across its model components. The formulated optimization problem is non-convex, highly nonlinear, and potentially has multiple-minima. Lastly, we show —through a real-world application— that the proposed solution procedure outperforms other state-of-the-art purely simulation-based optimization approaches in terms of computational efficiency, stability, and convergence. We also compare various gradient-based solution algorithms to determine the best algorithm to update the parameters. This work has the potential to facilitate wider and easier application of activity-based model-systems.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Joint routing of conventional and range-extended electric vehicles in a large metropolitan network

Range-extended electric vehicles combine the higher efficiency and environmental benefits of battery-powered electric motors with the longer mileage and autonomy of conventional internal combustion engines. This combination is particularly advantageous for time-constrained delivery routing in dense urban areas, where battery recharging along routes can be too time-consuming to economically justify the use of all-electric vehicles. However, switching from electric to conventional fossil fuel modes also results in higher costs and emissions and lower efficiency. This paper analyzes this heterogeneous vehicle routing problem and describes two solution methods: an exact branch-price-and-cut algorithm and an iterated tabu search metaheuristic. From a methodological perspective, we find that the exact algorithm consistently obtains tight lower bounds that also serve to certify the metaheuristic solutions as near-optimal. From a policy standpoint, we examine a large-scale real-world case study concerning parcel deliveries in the Chicago metropolitan area and quantify various operational metrics including energy costs and vehicle miles traveled. We find that by deploying roughly 20% of range -extended vehicles with a modest all-electric range of 33 miles, parcel distributors can save energy costs by up to 17% while incurring less than 0.5% increase in vehicle miles traveled. Increasing the range to 60 miles further reduces costs by only 4%, which can alternatively be achieved by decreasing the average service time by 1 minute or increasing driver working time by 1 hour. In conclusion, our study reveals several key areas of improvement on which vehicle manufacturers, distributors, and policy makers can focus their attention.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2021

Estimating Energy Bounds for Adoption of Shared Micromobility

Shared micromobility has garnered widespread popularity in recent years, but limited attention has been given to the energy impacts of trips replaced by micromobility. This paper investigates the energy bounds of shared micromobility adoption. Travel demand data at the national and city level were analyzed to identify trips that can be served through micromobility, and scenarios with varying levels of micromobility adoption were evaluated. Results show that peak adoption of shared micromobility can reduce energy consumption from reported passenger travel by 1% at the national level and 2.6% at the city level, with micromobility-induced transit trips identified as the largest contributor for energy reduction. Sensitivity analysis was carried out to show how the energy impacts would change with various levels of key micromobility-related parameters, and results show distance threshold having a stronger influence on the energy impacts, compared to redistribution energy intensity.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Comparison of direct and CO 2 -oxidative dehydrogenation of propane

Propane dehydrogenation to propylene has received increasing attention due to the fast growth in propylene demand and the exploration of shale gas containing propane. Direct dehydrogenation of propane (DDHP) offers high propylene selectivity but is limited by quick deactivation due to coke formation. CO 2 -assisted oxidative dehydrogenation of propane (CO 2 -ODHP) can consume CO 2 and meanwhile reduce coke deposition via the reverse Boudouard reaction. Here in the current review, direct and CO 2 -assisted dehydrogenation of propane has been compared from three aspects: reaction mechanisms, catalyst compositions, and CO 2 footprint analysis. As the average CO 2 emissions from electricity generation decrease due to the utilization of renewable energy, CO 2 -ODHP potentially leads to a net-negative CO 2 footprint while DDHP cannot.

58 GEOSCIENCES↗
DOE OSTI2024

Innovative biphasic solvent systems for lignocellulosic biorefinery

Bioconversion of lignocellulosics to ethanol is significantly hindered by biomass recalcitrance and, therefore, often requires a biomass pretreatment step. Furan-based compounds such as furfural (FF) and 5-hydroxymethylfurfural (HMF) are versatile building blocks for fuels and chemicals. However, their production during pretreatment often suffers from low yield and low separation efficiency. Biphasic solvent systems are capable of reducing biomass recalcitrance and extracting furans into the organic phase, thus preventing their degradation, increasing their yield, and allowing much easier separation. The development of a sustainable biphasic solvent system is essential to the furan-driven biorefinery and has drawn significant attention. Finally, this review systematically summarizes recent advances in the development of biphasic solvent systems in lignocellulosic biorefinery for improving the production of liquid fuels and furan-based compounds.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Disorder driven variations in magnetoresistance and planar Hall effect in Bi 2 Te 3 thin films

The degenerately doped sesquichalcogenide Bi 2 Te 3 , a well-known thermoelectric material, has attracted much attention in recent years as a topological insulator in which conducting surface states lead to exotic electronic transport. Here, in this study, we report the observation of anisotropic magnetoresistance (AMR) and planar Hall effect (PHE) in polycrystalline thin films of Bi 2 Te 3 over a broad range of temperature and magnetic field strength. The values of AMR, PHE and the Hall mobility (μ H ) are compared with results of similar measurements on single crystals and epitaxial films of Bi 2 Te 3 , where these properties are understood in the framework of electronic transport in the topologically protected conducting surface states. Our textured polycrystalline films show a robust metallic character with a carrier density (n s ) and mobility μ H of 9×10 20 cm -3 and 16.7 cm 2 V -1 s -1 respectively. This carrier density is higher and the mobility lower by an order of magnitude compared to the reported values of n s and μ H in epitaxial films and single crystals. However, we see a comparable AMR and PHE in our films for which the concept of conducting surface states is ill-defined due to their polycrystallinity and disordered structure. We suggest that an anisotropic backscattering of charge carriers in the strongly spin – orbit coupled electronic states of this heavy-metal-based non-magnetic compound may lead to the measured resistivity anisotropy. The observation of AMR and PHE in polycrystalline films may be important for scalable production of Bi 2 Te 3 based AMR and PHE sensors of magnetic fields.

36 MATERIALS SCIENCE↗
DOE OSTI2022

In-situ ATR-IR monitoring of hydrothermal carbonation of wollastonite

In-situ reaction monitoring allows for the development of reaction models for hydrothermal carbonation reactions, which have recently gained attention due to their importance in CO 2 sequestration and utilization. Here, we measured the carbonation kinetics of wollastonite (β- CaSiO 3 ) powder compacts under hydrothermal conditions (90°C and 2.4atm) with the help of optical fiber-based attenuated total reflectance infrared spectroscopy (ATR-IR). Further, the fiber probe was positioned at the target area to study the reaction chemistry at the desired region of the powder compact. Absorbances of solid reactants and products were monitored throughout the entire reaction in the 1000–1600cm -1 spectral range. ATR-IR enabled the detection of amorphous silica, which allowed all solid reactants (β-CaSiO 3 ) and products (CaCO 3 and SiO 2 ) to be monitored independently and simultaneously. A linear proportionality constant between absorbance and CaCO 3 phase concentration was determined and used to construct a reaction kinetics profile for carbonate formation, which revealed a rapid reaction onset, followed by two distinct slower decaying regimes.

42 ENGINEERING↗
DOE OSTI2021

Contributions of biofilm-induced flow heterogeneities to solute retention and anomalous transport features in porous media

We report that microbial biofilms are ubiquitous within porous media and the dynamics of their growth influence surface and subsurface flow patterns which impacts the physical properties of porous media and large-scale transport of solutes. Here, a two-dimensional pore-scale numerical model was used to evaluate the impact of biofilm-induced flow heterogeneities on conservative transport. Our study integrates experimental biofilm images of Paenibacillus 300A strain in a microfluidic device packed with cylindrical grains in a hexagonal distribution, with mathematical modeling. Biofilm is represented as a synthetic porous structure with locally varying physical properties that honors the impact of biofilm on the porous medium. We find that biofilm plays a major role in shaping the observed conservative transport dynamics by enhancing anomalous characteristics. More specifically, when biofilm is present, the pore structure in our geometry becomes more spatially correlated. We observe intermittent behavior in the Lagrangian velocities that switches between fast transport periods and long trapping events. Our results suggest that intermittency enhances solute spreading in breakthrough curves which exhibit extreme anomalous slope at intermediate times and very marked late solute arrival due to solute retention. The efficiency of solute retention by the biofilm is controlled by a transport regime which can extend the tailing in the concentration breakthrough curves. These results indicate that solute retention by the biofilm exerts a strong control on conservative solute transport at pore-scale, a role that to date has not received enough attention.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Opportunities for iron and steel industrial wastewater treatment and reuse in the United States

Concerns around water security in the United States have heightened the interest in industrial water treatment and reuse to improve water efficiency and operational reliability. Alongside nationwide efforts to expand industrial capacity, primary manufacturing sectors are adopting more resource-efficient technologies. This transition is expected to shift industrial water consumption patterns, driving the need for improved treatment and reuse practices. This study investigates opportunities for water use, treatment, and reuse in the iron and steel sector through a review of academic and industry literature and interviews with industry representatives. It identifies key challenges in water and wastewater management and outlines the conditions under which innovative treatment technologies could be deployed. Based on these insights, the study presents a practical water management action plan. Furthermore, it assesses water quality targets across different process operations, evaluates existing treatment technologies, and highlights challenges and opportunities for improvement relative to future performance expectations. Although water is often perceived as a low-cost commodity, industry feedback suggests that improvements in water use and treatment efficiency are typically prioritized only when they also reduce energy use, carbon emissions, or costs. This study advocates for a direct two-way partnership between industry and research audiences to bring their attention toward sustainable industrial water use, treatment, and reuse.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2020

Fiber-Shaped Fluidic Nanogenerator with High Power Density for Self-Powered Integrated Electronics

Flow-based hydrovoltaic nanogenerators have attracted particular attention as efficient and facile miniature energy-harvesting devices. However, they deliver relatively low output power density and limited power conversion efficiency owing to inefficient charge separation and poor charge accumulation. Here, we report the fabrication of high-performance, fiber-shaped fluidic nanogenerators (FFNGs) that use MoS 2 -encapsulated C fibers. The FFNGs deliver stable output voltages of 540 mV and an ultrahigh power density of 10.8 W m -2 . With experiments and density functional theory calculations, improvements in output performance can be attributed to smaller energy requirements for Na + cation adsorption, increased charge separation, and diffusion layer formations on the near surface. Moreover, self-powered, integrated devices achieve a maximum total power conversion-storage efficiency of ~11% and stable output voltage up to 3.1 V, which is applicable for use in consumer electronics devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Networks and interfaces as catalysts for polymer materials innovation

Autonomous experimental systems offer a compelling glimpse into a future where closed-loop, iterative cycles—performed by machines and guided by artificial intelligence (AI) and machine learning (ML)—play a foundational role in materials research and development. This perspective draws attention to the roles of networks and interfaces—of and between humans and machines—for the purpose of generating knowledge and accelerating innovation. Polymers, a class of materials with massive global impact, present a unique opportunity for the application of informatics and automation to pressing societal challenges. To develop these networks and interfaces in polymer science, the Community Resource for Innovation in Polymer Technology (CRIPT)—a polymer data ecosystem based on novel polymer data model, representation, search, and visualization technologies—is introduced. The ongoing co-design efforts engage stakeholders in industry, academia, and government to uncover rapidly actionable, high-impact opportunities to build networks, bridge interfaces, and catalyze innovation in polymer technology.

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

Significant charge transport effects due to subtle molecular changes in nitroxide radical single crystals

Radical-containing materials have received renewed interest due to their charge-conducting properties. However, most work focuses on macromolecules, while less attention has been paid to radical-containing small molecules. Here, we quantify the electrical conductivity in two organic radical single crystals and demonstrate that a subtle change in atomic connectivity drastically alters the macroscopic electronic properties of the materials. One radical crystal has an electrical conductivity of 3S m –1 , which is the among the highest values for nonconjugated radical conductors over a 1 μm scale. However, the other radical crystal has a 1,000-fold lower conductivity, despite their extremely similar molecular structures. The temperature-dependent conductivity follows the variable range hopping mechanism for both radical crystals, and the difference in effective charge mobility is the reason for the conductivity difference. These results present a clear picture of the design rules and charge transport mechanism for radical-based small-molecule materials.

36 MATERIALS SCIENCE↗