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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 1,621 records · Page 90
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

TRANSFORM: Catalyzing the Transition to a 21st Century Energy Economy - JISEA 2019 Annual Report

The Joint Institute for Strategic Energy Analysis (JISEA) provides leading-edge, objective, high impact research and analysis to guide transformative global energy investment and policy decisions. Through strategic insights and worldwide dialogue, JISEA explores the intersections of the environmental, social, financial, technological, and political elements of energy systems on the path to a clean energy economy. JISEA's work informs innovative solutions that advance the goals of sustainability, economic prosperity, and resilience. JISEA research and analysis provided decision-making support to industry, the financial sector, and government with a focus on the following strategic areas: Energy Systems Integration and Transformation, Energy in the Global Water-Food Nexus, and Circular Energy Economy.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2020

FY20 NREL Overview: Transforming Energy

At the National Renewable Energy Laboratory (NREL), we are transforming today’s energy challenges into tomorrow’s solutions. Our scientific research and technological innovation will shape a highly efficient and resilient energy future. Our world is transforming around us with energy solutions becoming cleaner, cheaper, renewable, and more resilient. As the population grows and new technologies and devices are added to the grid, we must examine the effects and enhance security within our most critical systems. As environmental threats expand and human demands on urban centers increase, we need more sustainable and efficient ways of generating energy that considers resource competition worldwide. We need our grid to be adaptive, autonomous, and responsive. NREL continues to anticipate these challenges, offering solutions through research, innovation, analysis, partners, and people. We are building the foundation of tomorrow’s energy landscape and inspiring the economic growth of the future.

energy security↗
DOE OSTI2022

Women in Power System Transformation

The United States Agency for International Development (USAID) – National Renewable Energy Laboratory (NREL) Partnership and the Global Power System Transformation (G-PST) Consortium joined together to launch the Women in Power System Transformation initiative. This initiative aims to increase gender equality in the global transition to clean energy by providing in-depth technical capacity building for women in emerging economies, so they are prepared to excel in science and engineering professional roles in the rapidly evolving power sector.

energy equity↗
DOE OSTI2012

Y-12 National Security Complex's Sustainable Recovery and Transformation - 12420

American Recovery and Reinvestment Act (ARRA) funds were used at the Y-12 National Security Complex (Y-12) to remove legacy materials from large contaminated excess facilities in order to prepare the facilities for demolition, demolish five excess buildings, and clean up sources of environmental contamination. The legacy materials and buildings presented many challenges and the potential hazards included depleted uranium and other radiological contaminants, lead, polychlorinated biphenyls, Freon, mold, mildew, asbestos, beryllium and mercury. Y-12 project teams have integrated sustainable waste management practices into each of the seven ARRA projects. The ARRA clean up efforts have resulted in the reduction of potential environmental, health, and safety risks posed by the excess facilities and sources of environmental contamination. Y-12's ARRA project teams focused on completing the activities in a sustainable, timely and safe manner. The site utilized a systematic material disposition evaluation process to ensure that materials were not automatically dis-positioned as waste. ARRA projects have recycled or reused over 1.3 million pounds of materials while preventing over 3 million vehicle miles traveled for waste disposal. Y-12 ARRA projects have worked over 2 million safe work hours without a lost time injury. The site has already begun to beneficially reuse land cleared by ARRA project activities to support sustainable transformation efforts. The Y-12 ARRA project activities have demonstrated that large complex projects can be completed sustainably and safely while maintaining an aggressive schedule. Through careful planning and execution, ARRA projects at the site have sustainably reduced the potential environmental, health, and safety risks posed to site employees and the community by the excess facilities and sources of environmental contamination. Y-12's systematic material disposition process ensured that materials were not automatically assumed to be wastes and facilitated the evaluation of all unneeded materials for reuse or recycling. The site's pervasive pollution prevention culture is reflected in the recycling or reuse of over 1.3 million pounds of materials by the ARRA project teams. While the disposal of a large volume of ARRA wastes could not be avoided, the projects were able to reduce the local and national impacts of waste transportation and disposal through careful planning and efficient execution. The site has conserved natural resources through the preservation and beneficial reuse of materials and land cleared by ARRA activities. Y-12 has taken steps to preserve its history as the site undergoes a sustainable and safe transformation for the future. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Introduction of a Variable Inductance Transformer for the Design of Resonant Power Converters

Magnetic integration is a hot topic in power electronics that concerns the use of a transformer’s leakage and magnetizing inductances purposefully in isolated power electronic converters, thereby giving the opportunity to save the cost and footprint of any additional inductor. This is of prime interest, especially in CLLLC resonant converters which require up to three inductors. For a complete integration of these inductances, the concept of a variable inductance transformer (VIT) is introduced in this thesis. A VIT is an adaptive magnetic structure that facilitates an easy adjustment of both magnetizing and leakage inductances to meet their desired values. However, for a more promising design, an accurate estimation of these inductances is necessary. While the evaluation of magnetizing inductance is quite straightforward, the calculation of leakage inductance is rather convoluted, because the leakage inductance is influenced by both the winding layout and the operating frequency. In this thesis, three new semi-analytical methods for calculating the frequency-independent leakage inductance, and a novel semi-analytical method for evaluating the frequency-dependent leakage inductance are proposed. These methods can calculate the respective leakage inductances of a VIT within an outstanding ±5% uncertainty. Finally, a bidirectional CLLLC resonant dc-dc converter is investigated for the constant current constant voltage (CCCV) charging of the next-generation 900 V traction battery of an electric vehicle. A new voltage gain equation is derived for designing the CLLLC resonant tank, and a small-signal model is presented for designing the variable-frequency feedback controller. Furthermore, a new methodology to design a VIT is developed to overcome the challenges associated with small coupling coefficients and guarantee a complete magnetic integration of the tank inductances. All theoretical results presented herein are verified through simulations and experiments performed on hardware prototypes designed in the lab.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

Non-Stationary Power System Forced Oscillation Analysis using Synchrosqueezing Transform

Non-stationary forced oscillations (FOs) have been observed in power system operations. However, most detection methods assume that the frequency of FOs is stationary. In this paper, we present a methodology for the analysis of nonstationary FOs. Firstly, Fourier synchrosqueezing transform (FSST) is used to provide a concentrated time-frequency representation of the signals that allows identification and retrieval of non-stationary signal components. To continue, the Dissipating Energy Flow (DEF) method is applied to the extracted components to locate the source of forced oscillations. The methodology is tested using simulated as well as real PMU data. In conclusion, the results show that the proposed FSST-based signal decomposition provides a systematic framework for the application of DEF Method to non-stationary FOs.

42 ENGINEERING↗
DOE OSTI2011

THE INFRARED SPECTRUM OF URANIUM HOLLOW CATHODE LAMPS FROM 850 nm to 4000 nm: WAVENUMBERS AND LINE IDENTIFICATIONS FROM FOURIER TRANSFORM SPECTRA

We provide new measurements of wavenumbers and line identifications of 10, 100 U I and U II near-infrared (NIR) emission lines between 2500 cm{sup -1} and 12, 000 cm{sup -1} (4000-850 nm) using archival Fourier transform spectrometer spectra from the National Solar Observatory. This line list includes isolated uranium lines in the Y, J, H, K, and L bands (0.9-1.1 {mu}m, 1.2-1.35 {mu}m, 1.5-1.65 {mu}m, 2.0-2.4 {mu}m, and 3.0-4.0 {mu}m, respectively), and provides six times as many calibration lines as thorium in the NIR spectral range. The line lists we provide enable inexpensive, commercially available uranium hollow cathode lamps to be used for high-precision wavelength calibration of existing and future high-resolution NIR spectrographs.

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

Radio-Frequency Rapid Thermal Processing Enabling Spatial Phase Transformation and Nanocrystallization of Soft Magnetic Amorphous Alloys

Thermal processing of soft magnetic amorphous and nanocrystalline alloys is explored under the influence of radio-frequency induction-heating techniques. Direct induction-heating concepts based on longitudinal and transverse flux heating are examined and the details of electromagnetic fields interaction with metallic strips are discussed by analytical calculations as well as finite element analysis. Initial experimental results confirming spatial control of phase transformations and nanocrystallization within a single strip of Finemet Fe-based amorphous ribbons are reported. Here, the degree to which primary and secondary crystallization temperature are achieved depends on the spacing between the ribbon relative to the induction coil as well as the coil design and configuration. For transverse coil configurations, the local temperature and therefore microstructural evolution is different across the lateral dimension of processed ribbons, with reduced gap sizes producing enhanced peak temperatures and larger temperature distributions with greater spatial variation in microstructure. In addition, indirect susceptor-based induction heating under tension is performed and the impact of microstructure is demonstrated. Herein, potential for exploiting spatially optimized phase transformations is illustrated through electromagnetic field–assisted processing in a scalable manufacturing process with amorphous and nanocrystalline soft magnetic alloys.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Detection and Signal Processing for Near-Field Nanoscale Fourier Transform Infrared Spectroscopy

Researchers from a broad spectrum of scientific and engineering disciplines are increasingly using scattering-type near-field infrared spectroscopic techniques to characterize materials non-destructively with nanoscale spatial resolution. However, a sub-optimal understanding of a technique's implementation can complicate data interpretation and act as a barrier to entering the field. Here the key detection and processing steps involved in producing scattering-type near-field nanoscale Fourier transform infrared spectra (nano-FTIR) are outlined. The self-contained mathematical and experimental work derives and explains: i) how normalized complex-valued nano-FTIR spectra are generated, ii) why the real and imaginary components of spectra qualitatively relate to dispersion and absorption respectively, iii) a new and generally valid equation for spectra which can be used as a springboard for additional modeling of the scattering processes, and iv) an algebraic expression that can be used to extract an approximation to the sample's local extinction coefficient from nano-FTIR. The algebraic model for weak oscillators is validated with nano-FTIR and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra on samples of polystyrene and Kapton and further provides a pedagogical pathway to cementing some of the technique's key qualitative attributes.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Preparation of 2D Polyaniline/MoO 3– x Superlattice Nanosheets via Intercalation-Induced Morphological Transformation for Efficient Chemodynamic Therapy

Organic intercalation of layered nanomaterials is an attractive strategy to fabricate organic/inorganic superlattices for a wide range of promising applications. However, the synthesis of 2D organic/inorganic superlattice nanosheets remains a big challenge. In this work, the preparation of 2D polyaniline/MoO 3–x (PANI/MoO 3–x ) superlattice nanosheets via intercalation-induced morphological transformation from MoO 3 nanobelts, as efficient Fenton-like reagents for chemodynamic therapy (CDT), is reported. Micrometer-long MoO 3 nanobelts are co-intercalated with Na + /H 2 O followed by the guest exchange with aniline monomer for in situ polymerization to obtain PANI/MoO 3–x nanosheets. Intriguingly, the PANI intercalation can induce the morphological transformation from long MoO 3 nanobelts to 2D PANI/MoO 3–x nanosheets along with the partial reduction of Mo 6+ to Mo 5+ , and generation of rich oxygen vacancies. More importantly, thanks to the PANI intercalation-induced activation, the PANI/MoO 3–x nanosheets exhibit excellent Fenton-like catalytic activity for generation of hydroxyl radical (·OH) by decomposing H 2 O 2 compared with the MoO 3 nanobelts. It is speculated that the good conductivity of PANI can facilitate electron transport during the Fenton-like reaction, thereby enhancing the efficiency of CDT. Thus, the polyvinylpyrrolidone-modified PANI/MoO 3–x nanosheets can function as Fenton-like reagents for highly efficient CDT to kill cancer cells and eradicate tumors.

2D materials↗
DOE OSTI2018

Real-Time Observation of Order-Disorder Transformation of Organic Cations Induced Phase Transition and Anomalous Photoluminescence in Hybrid Perovskites

A fundamental understanding of the interplay between the microscopic structure and macroscopic optoelectronic properties of organic-inorganic hybrid perovskite materials is essential to design new materials and improve device performance. However, how exactly the organic cations affect the structural phase transition and optoelectronic properties of the materials is not well understood. Here, real-time, in situ temperature-dependent neutron/X-ray diffraction and photoluminescence (PL) measurements reveal a transformation of the organic cation CH 3 NH 3 + from order to disorder with increasing temperature in CH 3 NH 3 PbBr 3 perovskites. The molecular-level order-to-disorder transformation of CH 3 NH 3 + not only leads to an anomalous increase in PL intensity, but also results in a multidomain to single-domain structural transition. Lastly, this discovery establishes the important role that organic cation ordering has in dictating structural order and anomalous optoelectronic phenomenon in hybrid perovskites.

25 ENERGY STORAGE↗
DOE OSTI2018

Atomic-Scale Observation of Electrochemically Reversible Phase Transformations in SnSe 2 Single Crystals

2D materials have shown great promise to advance next-generation lithium-ion battery technology. Specifically, tin-based chalcogenides have attracted widespread attention because lithium insertion can introduce phase transformations via three types of reactions—intercalation, conversion, and alloying—but the corresponding structural changes throughout these processes, and whether they are reversible, are not fully understood. Here, the first real-time and atomic-scale observation of reversible phase transformations is reported during the lithiation and delithiation of SnSe 2 single crystals, using in situ high-resolution transmission electron microscopy complemented by first-principles calculations. Lithiation proceeds sequentially through intercalation, conversion, and alloying reactions (SnSe 2 → Li x SnSe 2 → Li 2 Se + Sn → Li 2 Se + Li 17 Sn 4 ) in a manner that maintains structural and crystallographic integrity, whereas delithiation forms numerous well-aligned SnSe 2 nanodomains via a homogeneous deconversion process, but gradually loses the coherent orientation in subsequent cycling. Furthermore, alloying and dealloying reactions cause dramatic structural reorganization and thereby consequently reduce structural stability and electrochemical cyclability, which implies that deep discharge for Sn chalcogenide electrodes should be avoided. Overall, the findings elucidate atomistic lithiation and delithiation mechanisms in SnSe 2 with potential implications for the broader class of 2D metal chalcogenides.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Probing Electrode Transformation under Dynamic Operation for Alkaline Water Electrolysis

Alkaline water electrolyzers (AWEs) play a pivotal role in the realm of large-scale hydrogen production. However, AWEs face significant challenges in electrode degradation particularly under dynamic operating conditions, induced by reverse current phenomenon during frequent startup/shutdown. Herein, this study aims to rationalize the degradation mechanisms of AWEs under these conditions. A three-electrode membrane electrode assembly (MEA) setup is first utilized to decouple polarization behaviors of anode and cathode in AWEs. Following a proposed accelerated stress testing protocol, the setup allows for tracking individual electrode performance transformations during frequent reverse current operation. Integrating operando cell studies with in situ and post-mortem characterizations, it is showed that continuous formation of highly active species, nickel (oxy)hydroxides, improves the anode performance for oxygen evolution reaction. On the contrary, irreversible oxidation of nickel to β-nickel hydroxide results in a severe degradation of cathode, leading to material dissolution, poor electrical conductivity and loss of catalytic activity for hydrogen evolution reaction. These results provide insights in nickel-based electrode transformation mechanisms for alkaline water electrolysis and indicate that cathode with higher redox reversibility can potentially improve durability of AWEs under dynamic conditions.

08 HYDROGEN↗
DOE OSTI2016

Low‐Energy Electron‐Induced Transformations in Organolead Halide Perovskite

Abstract Methylammonium lead iodide perovskite (MAPbI 3 ), a prototype material for potentially high‐efficient and low‐cost organic–inorganic hybrid perovskite solar cells, has been investigated intensively in recent years. A study of low‐energy electron‐induced transformations in MAPbI 3 is presented, performed by combining controlled electron‐impact irradiation with X‐ray photoelectron spectroscopy and scanning electron microscopy. Changes were observed in both the elemental composition and the morphology of irradiated MAPbI 3 thin films as a function of the electron fluence for incident energies from 4.5 to 60 eV. The results show that low‐energy electrons can affect structural and chemical properties of MAPbI 3 . It is proposed that the transformations are triggered by the interactions with the organic part of the material (methylammonium), resulting in the MAPbI 3 decomposition and aggregation of the hydrocarbon layer.

Milosavljević, Aleksandar R.↗
DOE OSTI2022

Perovskite Photocatalytic CO 2 Reduction or Photoredox Organic Transformation?

Abstract Metal‐halide perovskites have been explored as photocatalysts for CO 2 reduction. We report that perovskite photocatalytic CO 2 reduction in organic solvents is likely problematic. Instead, the detected products (i.e., CO) likely result from a photoredox organic transformation involving the solvent. Our observations have been validated using isotopic labeling experiments, band energy analysis, and new control experiments. We designed a typical perovskite photocatalytic setup in organic solvents that led to CO production of up to ≈1000 μmol g −1 h −1 . CO 2 reduction in organic solvents must be studied with extra care because photoredox organic transformations can produce orders of magnitude higher rate of CO or CH 4 than is typical for CO 2 reduction routes. Though CO 2 reduction is not likely to occur, in situ CO generation is extremely fast. Hence a suitable system can be established for challenging organic reactions that use CO as a feedstock but exploit the solvent as a CO surrogate.

San Martin, Jovan↗
DOE OSTI2016

Low‐Energy Electron‐Induced Transformations in Organolead Halide Perovskite

Abstract Methylammonium lead iodide perovskite (MAPbI 3 ), a prototype material for potentially high‐efficient and low‐cost organic–inorganic hybrid perovskite solar cells, has been investigated intensively in recent years. A study of low‐energy electron‐induced transformations in MAPbI 3 is presented, performed by combining controlled electron‐impact irradiation with X‐ray photoelectron spectroscopy and scanning electron microscopy. Changes were observed in both the elemental composition and the morphology of irradiated MAPbI 3 thin films as a function of the electron fluence for incident energies from 4.5 to 60 eV. The results show that low‐energy electrons can affect structural and chemical properties of MAPbI 3 . It is proposed that the transformations are triggered by the interactions with the organic part of the material (methylammonium), resulting in the MAPbI 3 decomposition and aggregation of the hydrocarbon layer.

Milosavljević, Aleksandar R.↗
DOE OSTI2022

Perovskite Photocatalytic CO 2 Reduction or Photoredox Organic Transformation?

Abstract Metal‐halide perovskites have been explored as photocatalysts for CO 2 reduction. We report that perovskite photocatalytic CO 2 reduction in organic solvents is likely problematic. Instead, the detected products (i.e., CO) likely result from a photoredox organic transformation involving the solvent. Our observations have been validated using isotopic labeling experiments, band energy analysis, and new control experiments. We designed a typical perovskite photocatalytic setup in organic solvents that led to CO production of up to ≈1000 μmol g −1 h −1 . CO 2 reduction in organic solvents must be studied with extra care because photoredox organic transformations can produce orders of magnitude higher rate of CO or CH 4 than is typical for CO 2 reduction routes. Though CO 2 reduction is not likely to occur, in situ CO generation is extremely fast. Hence a suitable system can be established for challenging organic reactions that use CO as a feedstock but exploit the solvent as a CO surrogate.

14 SOLAR ENERGY↗