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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Dynamically Unveiling Metal–Nitrogen Coordination during Thermal Activation to Design High‐Efficient Atomically Dispersed CoN 4 Active Sites

Abstract We elucidate the structural evolution of CoN 4 sites during thermal activation by developing a zeolitic imidazolate framework (ZIF)‐8‐derived carbon host as an ideal model for Co 2+ ion adsorption. Subsequent in situ X‐ray absorption spectroscopy analysis can dynamically track the conversion from inactive Co−OH and Co−O species into active CoN 4 sites. The critical transition occurs at 700 °C and becomes optimal at 900 °C, generating the highest intrinsic activity and four‐electron selectivity for the oxygen reduction reaction (ORR). DFT calculations elucidate that the ORR is kinetically favored by the thermal‐induced compressive strain of Co−N bonds in CoN 4 active sites formed at 900 °C. Further, we developed a two‐step (i.e., Co ion doping and adsorption) Co‐N‐C catalyst with increased CoN 4 site density and optimized porosity for mass transport, and demonstrated its outstanding fuel cell performance and durability.

He, Yanghua↗
DOE OSTI2021

Dynamically Unveiling Metal–Nitrogen Coordination during Thermal Activation to Design High-Efficient Atomically Dispersed CoN 4 Active Sites

We elucidate the structural evolution of CoN 4 sites during thermal activation by developing a zeolitic imidazolate framework (ZIF)-8-derived carbon host as an ideal model for Co 2+ ion adsorption. Subsequent in situ X-ray absorption spectroscopy analysis can dynamically track the conversion from inactive Co-OH and Co-O species into active CoN 4 sites. The critical transition occurs at 700 °C and becomes optimal at 900 °C, generating the highest intrinsic activity and four-electron selectivity for the oxygen reduction reaction (ORR). DFT calculations elucidate that the ORR is kinetically favored by the thermal-induced compressive strain of Co-N bonds in CoN 4 active sites formed at 900 °C. Further, we developed a two-step (i.e., Co ion doping and adsorption) Co-N-C catalyst with increased CoN 4 site density and optimized porosity for mass transport, and demonstrated its outstanding fuel cell performance and durability.

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

Guia de Calentadores de Agua con Bomba de Calor para Pequenas Empresas

Esta guia esta destinada a propietarios de edificios y administradores de instalaciones interesados en electrificar los sistemas de calentamiento de agua de edificios comerciales a traves de sistemas nuevos o reemplazos. Esta guia tambien es un recurso para que los contratistas se familiaricen con los calentadores de agua comerciales con bomba de calor. Esta guia se enfoca en equipos de calentadores de agua con bomba de calor de fuente de aire unitario (estilo tanque), y aqui se incluyen informacion basica, mejores practicas y consideraciones clave. Un ingeniero debe ayudar a identificar las consideraciones especificas exclusivas de los sistemas individuales, segun sea necesario. This is the Spanish translation of NREL/FS-5500-84401, Heat Pump Water Heater Guide for Small Businesses.

decarbonization↗
DOE OSTI2020

Materials Data on Zn(CoN)2 by Materials Project

Zn(CoN)2 crystallizes in the tetragonal P-4m2 space group. The structure is two-dimensional and consists of one Zn(CoN)2 sheet oriented in the (0, 0, 1) direction. Co2+ is bonded in a linear geometry to two equivalent N3- atoms. Both Co–N bond lengths are 1.73 Å. Zn2+ is bonded to four equivalent N3- atoms to form corner-sharing ZnN4 tetrahedra. All Zn–N bond lengths are 2.18 Å. N3- is bonded in a see-saw-like geometry to two equivalent Co2+ and two equivalent Zn2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(CoN)2 by Materials Project

Mg(CoN)2 crystallizes in the tetragonal P-4m2 space group. The structure is two-dimensional and consists of one Mg(CoN)2 sheet oriented in the (0, 0, 1) direction. Mg2+ is bonded to four equivalent N3- atoms to form corner-sharing MgN4 tetrahedra. All Mg–N bond lengths are 2.18 Å. Co2+ is bonded in a linear geometry to two equivalent N3- atoms. Both Co–N bond lengths are 1.73 Å. N3- is bonded in a see-saw-like geometry to two equivalent Mg2+ and two equivalent Co2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CoN by Materials Project

CoN crystallizes in the triclinic P1 space group. The structure is one-dimensional and consists of two CoN ribbons oriented in the (1, 0, 0) direction. Co3+ is bonded in a linear geometry to two equivalent N3- atoms. There is one shorter (1.68 Å) and one longer (1.69 Å) Co–N bond length. N3- is bonded in a linear geometry to two equivalent Co3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(CoN)2 by Materials Project

Ca(CoN)2 crystallizes in the tetragonal P-4m2 space group. The structure is two-dimensional and consists of one Ca(CoN)2 sheet oriented in the (0, 0, 1) direction. Ca2+ is bonded to four equivalent N3- atoms to form distorted corner-sharing CaN4 tetrahedra. All Ca–N bond lengths are 2.43 Å. Co2+ is bonded in a linear geometry to two equivalent N3- atoms. Both Co–N bond lengths are 1.73 Å. N3- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Co2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Pros and Cons Analysis of HALEU Utilization in Example Fuel Cycles

The Systems Analysis and Integration campaign assessed the pros and cons of high-assay low-enriched uranium (HALEU) utilization in advanced reactors and associated fuel cycles. The assessment was done for three example fuel cycles at equilibrium states: once-through, limited recycle, and continuous recycle (CR) starting with HALEU. Front- and back-end fuel cycle parameters and the Levelized Cost of Fuel (LCF), which is the Levelized Cost of Electricity excluding reactor cost, of the three example fuel cycles were calculated using a single Analysis Example Reactor. The pros and cons of HALEU utilization were assessed by normalizing the fuel cycle parameters and LCF to a unit of electricity generation (GWe-year) and comparing them with a Basis of Comparison. In this study, a sodium-cooled reactor with sodium-bonded metallic fuel having a burnup of ~100 GWd/t was used as the Analysis Example Reactor because its technology readiness level is high, and the burnup and fuel enrichment are in the middle of those ranges of advanced reactor concepts that are under development. The current once-through Light Water Reactors (OT-LWRs) with <5% low-enriched uranium and 50 GWd/t burnup were used as the Basis of Comparison. In addition, a series of sensitivity analyses was conducted by varying burnup, enrichment, fuel forms, and reactor types to capture the design variations in two once-through Advanced Reactor Demonstration Program (ARDP) reactors, Natrium with sodium-free metallic fuel having a burnup of ~150 GW/t and Xe-100 with Tristructural-Isotropic (TRISO) pebble fuel having a burnup of ~168 GWd/t.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1977

Carry-on Shuttle payloads, or how to 'CON' the system

The three types of life-science payload carried by the Space Shuttle are briefly discussed. These are the carry-on (CON), the minilab, and the dedicated life-science laboratory. The latter two payloads relate to experiments with animals, plants, and other biological forms. The CON payload is a package weighing up to 200 lb (up to 5 cu ft in size) which, without requiring a crew interface nor direct connection with the Shuttle, will provide such support as power, cooling, feeding, etc. The configuration and principal characteristics of each type of payload are presented.

Winter, D. L.↗
DOE OSTI2020

Materials Data on CoN by Materials Project

CoN is Zincblende, Sphalerite structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Co3+ is bonded to four equivalent N3- atoms to form corner-sharing CoN4 tetrahedra. All Co–N bond lengths are 1.84 Å. N3- is bonded to four equivalent Co3+ atoms to form corner-sharing NCo4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CoN by Materials Project

CoN is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Co3+ is bonded in a body-centered cubic geometry to eight equivalent N3- atoms. All Co–N bond lengths are 2.18 Å. N3- is bonded in a body-centered cubic geometry to eight equivalent Co3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CoN by Materials Project

CoN is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Co3+ is bonded to six equivalent N3- atoms to form a mixture of edge and corner-sharing CoN6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Co–N bond lengths are 2.00 Å. N3- is bonded to six equivalent Co3+ atoms to form a mixture of edge and corner-sharing NCo6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(CoN)2 by Materials Project

Ba(CoN)2 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight equivalent N3- atoms. All Ba–N bond lengths are 3.23 Å. Co2+ is bonded in a distorted trigonal planar geometry to three equivalent N3- atoms. There is one shorter (1.76 Å) and two longer (1.81 Å) Co–N bond length. N3- is bonded in a 3-coordinate geometry to four equivalent Ba2+ and three equivalent Co2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Surface Charge and Electrostatic Spin Crossover Effects in CoN 4 Electrocatalysts

Carbon materials doped with nitrogen and 3d transition metals have attracted a great deal of interest for catalyzing electrochemical reactions such as water splitting, oxygen reduction, and carbon dioxide reduction. Here, we employed density functional theory to study Co–N-doped carbon as electrocatalysts for the oxygen reduction and oxygen evolution reactions. Specifically, we investigated the interplay among adsorption energies, the spin state of the CoN 4 active center, and the applied potential. We found that adsorption energies strongly depend on both the applied potential and the spin state of the Co center. Furthermore, spin state transitions induced by the applied potential also play an important role in determining the adsorption energies. Here, this effect originates from a different potential of zero charge and capacitance of each spin state.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Con Connections: Detecting Fraud from Abstracts using Topological Data Analysis

In this paper we present a novel approach for identifying fraudulent papers from their titles and abstracts. The premise of the approach is that there are holes in the presentation of the approach and findings of fraudulent research papers. As an abstract is intended to highlight key features of the approach as well as important conclusions the authors seek to determine if the assumed existence of holes can be identified from analysis of abstracts alone. The data set considered is derived from papers sharing a single author with labels determined based on a formal linguistic analysis of the complete documents. To detect these logical and literary holes we utilize techniques from topological data analysis which summarizes data based on the presence of multi-dimensional, topological holes. We find that, in fact, topological features derived through a combination of techniques in natural language processing and time-series analysis allow for superior detection of the fraudulent papers than the natural language processing tools alone. Thus we conclude that the connections and holes present in the abstracts of research cons contributes to an ability to infer the scientific validity of the corresponding work.

Tymochko, Sarah J.↗
NASA NTRS2009

Pros and Cons of Using Arrays of Small Antennas Versus Large Single Dish Antennas for the Deep Space Network

This paper briefly describes pros and cons of using arrays of small antennas instead of large single dish antennas for spacecraft telemetry, command, and tracking (TT and C) - communications and navigation (C and N) - and science support that the Deep Space Network (DSN) normally provides. It considers functionality and performance aspects, mainly for TT and C, though it also considers science. It only briefly comments on the cost aspects that seem to favor arrays of small antennas over large single antennas, at least for receiving (downlinks).

Deep Space Network↗
NASA NTRS2011

Pros, Cons, and Alternatives to Weight Based Cost Estimating

Many cost estimating tools use weight as a major parameter in projecting the cost. This is often combined with modifying factors such as complexity, technical maturity of design, environment of operation, etc. to increase the fidelity of the estimate. For a set of conceptual designs, all meeting the same requirements, increased weight can be a major driver in increased cost. However, once a design is fixed, increased weight generally decreases cost, while decreased weight generally increases cost - and the relationship is not linear. Alternative approaches to estimating cost without using weight (except perhaps for materials costs) have been attempted to try to produce a tool usable throughout the design process - from concept studies through development. This paper will address the pros and cons of using weight based models for cost estimating, using liquid rocket engines as the example. It will then examine approaches that minimize the imp~ct of weight based cost estimating. The Rocket Engine- Cost Model (RECM) is an attribute based model developed internally by Pratt & Whitney Rocketdyne for NASA. RECM will be presented primarily to show a successful method to use design and programmatic parameters instead of weight to estimate both design and development costs and production costs. An operations model developed by KSC, the Launch and Landing Effects Ground Operations model (LLEGO), will also be discussed.

Joyner, Claude R.↗
DOE OSTI2020

Materials Data on V(CoN)4 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗