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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 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Influence of Time and Frequency Domain Wave Forcing on the Power Estimation of a Wave Energy Converter Array

Industry-specific tools for analyzing and optimizing the design of wave energy converters (WECs) and associated power systems are essential to advancing marine renewable energy. This study aims to quantify the influence of phase information on the device power output of a virtual WEC array. We run the phase-resolving wave model FUNWAVE-TVD (Total Variation Diminishing) to generate directional waves at the PacWave South site offshore from Newport, Oregon, where future WECs are expected to be installed for testing. The two broad cases presented correspond to mean wave climates during warm months (March–August) and cold months (September–February). FUNWAVE-TVD time series of sea-surface elevation are then used in WEC-Sim, a time domain numerical model, to simulate the hydrodynamic response of each device in the array and estimate their power output. For comparison, WEC-Sim is also run with wave energy spectra calculated from the FUNWAVE-TVD simulations, which do not retain phase information, and with wave spectra computed using the phase-averaged model Simulating WAves Nearshore (SWAN). The use of spectral data in WEC-Sim requires a conversion from frequency to time domain by means of random superposition of wave components, which are not necessarily consistent because of the linear assumption implicit in this method. Thus, power response is characterized by multiple realizations of the wave climates.

13 HYDRO ENERGY↗
NASA NTRS1973

Parabolic cylinder antennas

Some of the features of single and dual parabolic-cylinder reflector antenna systems are discussed in terms of wave conversions, field divergence, and wavefronts in Fresnel and Fraunhofer regions. Beam-squinting, by mechanical displacement and electrical phase gradient methods, is introduced together with the combination of these methods. In the case of dual parabolic cylinders there is also a discussion of surface-truncation, parametric representation of surface intersections, main-aperture blockage by the subsystem, and beam squinting. A few diffraction patterns are presented to illustrate the type of data available via a formulation equivalent to the complex-vector Kirchhoff-Kottler formulation. Main and cross-polarization components of the solution are available as they are inherently part of the field solution in the Cartesian coordinate system. A means of displaying main and cross-polarization components for arbitrary beam-scanning in space is outlined. Extensions to monopulse tracking with variable-beamwidth (zooming) capability are introduced.

Schmidt, R. F.↗
NASA NTRS1992

SP-100 reactor with Brayton conversion for lunar surface applications

Examined here is the potential for integrating Brayton-cycle power conversion with the SP-100 reactor for lunar surface power system applications. Two designs were characterized and modeled. The first design integrates a 100-kWe SP-100 Brayton power system with a lunar lander. This system is intended to meet early lunar mission power needs while minimizing on-site installation requirements. Man-rated radiation protection is provided by an integral multilayer, cylindrical lithium hydride/tungsten (LiH/W) shield encircling the reactor vessel. Design emphasis is on ease of deployment, safety, and reliability, while utilizing relatively near-term technology. The second design combines Brayton conversion with the SP-100 reactor in a erectable 550-kWe powerplant concept intended to satisfy later-phase lunar base power requirements. This system capitalizes on experience gained from operating the initial 100-kWe module and incorporates some technology improvements. For this system, the reactor is emplaced in a lunar regolith excavation to provide man-rated shielding, and the Brayton engines and radiators are mounted on the lunar surface and extend radially from the central reactor. Design emphasis is on performance, safety, long life, and operational flexibility.

Mason, Lee S.↗
NASA NTRS1995

Preparation Of Strong, Dense Potassium Beta''-Alumina Ceramic

Improved process for making mechanically strong, dense, phase-pure potassium beta''-alumina solid electrolyte (K-BASE) results in material superior to all previous K-BASE preparations and similar to commercial Na-BASE in strength, phase purity and high-temperature ionic conductivity. Potassium-based alkali-metal thermal-to-electric conversion (AMTEC) cells expected to operate efficiently at lower heat-input temperatures and lower rejection temperatures than sodium-based AMTEC cells, making them appropriate for somewhat different applications.

Williams, Roger M.↗
NASA NTRS2000

The Ceres S'COOL Project: Two Years After First Launch

The idea for the Students' Cloud Observations OnLine (S'COOL) project as an outreach and education element of NASA's Clouds and the Earth's Radiant Energy System (CERES) research program was conceived in late 1996 during a conversation with a middle school science teacher. S'COOL was implemented in a series of increasingly developed test phases during 1997, as the launch of the first CERES instrument approached. Even before launch, the reception of the project in schools far exceeded expectations. After several delays the first instrument, on the Tropical Rainfall Measuring Mission (TRMM) spacecraft, was launched on Thanksgiving Day, 1997. Since the first launch, development and expansion of the project has continued with expectations for launch of Terra carrying two CERES instruments into a polar orbit in mid-1998. That launch is now expected in fall 1999, and will finally provide overflight of all participating schools. In two years, the project has grown from three initial test participants to over 300 schools now participating in 23 countries on five continents. Students from first grade through university level are involved (most participants are ages 10-15). S'COOL is also being used by a few education professors to teach about Internet use in the classroom. The project continues to grow through word of mouth, presentations at teacher workshops, and now increasingly through teachers who find it during web searches. Participants in the S'COOL project are part of the CERES validation team. They provide ground truth measurements at the time the CERES instrument flies over their location, to be compared with the retrieval of cloud properties by remote sensing from CERES. Quantities reported include cloud type, height, fraction and opacity; information on contrails; surface temperature, pressure and relative humidity; and ground cover (snow/ice, wet, dry; leaves on trees or not). in addition, a comment field on the report form serves as a catch-all for all kinds of interesting observations, including similes written by some classes to describe more exactly the clouds they see. Several not totally unexpected complications with the CERES instrument and processing software mean that the CERES team has not yet reached the point of computing the cloud properties, a high level product at the end of the processing stream. However, progress is being made and we anticipate that we will soon be populating the S'COOL database with a large number of satellite retrievals for comparison with the students' observations. Some satellite retrievals from the initial test phases are already available in the database, The CERES instruments are planned to operate at least through 2006, and the S'COOL Project is planned to continue at least that long, providing motivational learning to as many students as possible. This paper reports on the first several years of the S'CCOL project. It further reports on some of the noteworthy observations and comparisons made possible by this project. Schools are often located in interesting places, in terms of the clouds found there and the satellite's ability to observe these clouds. The paper also reports on the learning opportunities delivered by this project, and on new questions about the planet and its climate which arise in the students' minds as a result of their active participation.

Chambers, Lin H.↗
DOE OSTI2021

Method of making a perovskite layer at high speed

A method of making a perovskite layer includes providing a flexible substrate; providing a perovskite solution comprising an initial amount of solvent and perovskite precursor materials and a total solids concentration between 30 percent and 70 percent by weight of its saturation concentration; depositing the perovskite solution on the flexible substrate; removing a first portion of the solvent from the deposited perovskite solution and increasing the total solids concentration of the perovskite solution to at least 75 percent of its saturation concentration with a first drying step; and removing a second portion of the solvent from the deposited perovskite solution with a second drying step having a higher rate of solvent evaporation that causes saturation and a conversion reaction in the deposited perovskite solution resulting in perovskite crystal formation or formation of a perovskite intermediate phase, wherein the first drying step dwell time is at least 5 times longer than the second drying step dwell time.

Christensen, Scott Kenneth↗
DOE OSTI2021

Zeolitic-Imidazolate Framework Derived Intermetallic Nickel Zinc Carbide Material as a Selective Catalyst for CO 2 to CO Reduction at High Pressure

The conversion of CO 2 into CO is an important step in CO 2 utilization to achieve clean fuels and value-added chemicals. Herein, we explored the pyrolysis of zeolitic imidazolate framework-8 (ZIF-8) loaded with different amounts of Ni 2+ to obtain Ni-Zn carbide (Ni 3 ZnC) embedded in N-doped carbon. Ni is present in the intermetallic compound, while Zn excess remains on the N-doped carbon. The Ni 3 ZnC phase catalyzes the selective hydrogenation of CO 2 into CO via the reverse water gas shift reaction, reaching 100 % CO selectivity at ~30 % CO 2 conversion at 450 °C and atmosphere pressure (CO 2 :H 2 =1:4, GHSV=30000 mL g cat -1 h -1 ). The methanation reaction of CO 2 /CO, which is usually favored over Ni catalysts, is suppressed. The selectivity to CO at the expense of CH 4 is related to the stability of chemisorbed CO in the Ni 3 ZnC surface, which is lower compared to Ni surfaces. The Ni 3 ZnC@NC catalyst is selective towards CO over a wide range of conditions, including high pressure, that is usually required for the conversion of CO to hydrocarbons and alcohols via the Fisher-Tropsch synthesis (FTS) process. Contrarily, a classical Ni/SiO 2 catalyst prepared by impregnation produces CH 4 under high pressure.

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

Integrated Capture and Conversion of CO 2 to Methanol (ICCCM) Process Technology - CRADA 449 (Final Report)

The goal of this project is to develop a prototype system that integrates the capture and catalytic hydrogenation of CO 2 into methanol in the same solvent. Ultimately, this integrated approach could provide a technology with projected reductions to capital and operating costs by at least 20% relative to a benchmark methanol synthesis via gas-phase CO 2 hydrogenation. There were five primary objectives for the project: 1. Optimize the selections of both the catalysts and the CO 2 capture solvents to achieve high conversion (>80%) and high selectivity (>90%) toward methanol in the targeted processing ranges (100-180°C, 1-60 bar). 2. Design a reactor system that provides a fixed catalyst surface area and high-efficiency heat exchange to assure compact modular processing. 3. Build and test a reactor system and demonstrate in a bench scale continuous flow system, and use the operating data to refine the comparison to existing conversion technologies. 4. Refine techno economic (TEA) and Tech-to-Market (TTM) analyses using the experimental data obtained from the bench-scale system. 5. Use the experimental data and TEA/TTM projections to develop a conceptual design for a pre-commercial system that targets a specific market opportunity.

09 BIOMASS FUELS↗
DOE OSTI2021

Evolution of magnetic field induced ordering in the layered quantum Heisenberg triangular-lattice antiferromagnet Ba 3 CoSb 2 O 9

Quantum fluctuations in the effective spin-12 layered triangular-lattice quantum Heisenberg antiferromagnet Ba 3 CoSb 2 O 9 lift the classical degeneracy of the antiferromagnetic ground state in magnetic field, producing a series of novel spin structures for magnetic fields applied within the crystallographic ab plane, including a celebrated collinear “up-up-down” spin ordering with magnetization equal to 1/3 of the saturation magnetization over an extended field range. Theoretically unresolved, however, are the effects of interlayer antiferromagnetic coupling and transverse magnetic fields on the ground states of this system. Additional magnetic field induced phase transitions are theoretically expected and in some cases have been experimentally observed, but details regarding their number, location, and physical character appear inconsistent with the predictions of existing models. Conversely, an absence of experimental measurements as a function of magnetic-field orientation has left other key predictions of these models untested. To address these issues, in this study we have used specific heat, neutron diffraction, thermal conductivity, and magnetic torque measurements to map out the phase diagram as a function of magnetic field intensity and orientation relative to the crystallographic ab plane. For H||ab, we have discovered an additional magnetic field induced phase transition at low temperature and an unexpected tetracritical point in the high-field phase diagram, which coupled with the apparent second-order nature of the phase transitions eliminates several theoretically proposed spin structures for the high-field phases. Our calorimetric measurements as a function of magnetic field orientation are in general agreement with theory for field-orientation angles close to plane parallel (H||a) but diverge at angles near plane perpendicular; a predicted convergence of two phase boundaries at finite angle and a corresponding change in the order of the field induced phase transition are not observed experimentally. Our results emphasize the role of interlayer coupling in selecting and stabilizing field induced phases, provide guidance on the nature of the magnetic order in each phase, and reveal the need for new physics to account for the nature of magnetic ordering in this archetypal two-dimensional spin-12 triangular-lattice quantum Heisenberg antiferromagnet.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Controlling Polymer Morphology in Blade-Coated All-Polymer Solar Cells

In this report translating all-polymer solar cells from spin-coating to scalable roll-to-roll-compatible fabrication techniques is a critical step toward the application of organic photovoltaics at a scale. Techniques to control polymer crystallization and phase separation during solution printing are essential to obtain high-performance printed organic solar cells. Here, we demonstrate a novel solvent additive approach employing trace amounts of phthalates as additives to control polymer crystallinity and suppress unfavorable phase separation in a representative PTB7-Th/P(NDI2OD-2T) all-polymer solar cell. The best-performing additive increased the blade-coated device performance from 2.09 to 4.50% power conversion efficiency, an over twofold improvement, mitigating the loss in performance that is typically observed during process transfer from spin-coating to blade-coating. It is suggested that the improved device performance stems from a finer polymer phase-separation size and overall improved active layer morphology, evidenced by device characterization data and indirectly supported by grazing incidence wide-angle X-ray scattering analyses. Real-time X-ray diffraction measurements during blade-coating provide mechanistic insights and suggest that the dioctyl phthalate additive may act as a compatibilizer, reducing the demixing of the donor and acceptor polymer during film formation, enabling a smaller phase separation and improved performance. The structural diversity of the class of phthalate additives makes this simple yet effective concept promising for translating other all-polymer material systems to blade-coating and other scalable printing techniques.

14 SOLAR ENERGY↗
NASA NTRS1992

Theoretical study of the design of a catalyst for para to ortho hydrogen conversion

The theory of Petzinger and Scalapino (1973) was thoroughly reviewed, and all of the basic equations for paramagnetic para to ortho hydrogen catalysis re-derived. There are only a few minor phase errors and errors of omission in the description of the theory. Three models (described by Petzinger and Scalapino) for the rate of para to ortho H2 catalysis were worked out, and uniform agreement obtained to within a constant factor of 2 pi. The analytical methods developed in the course of this study were then extended to two new models, which more adequately describe the process of surface catalysis including transfer of hydrogen molecules onto and off of the surface. All five equations for the para to ortho catalytic rate of conversion are described. The two new equations describe the catalytic rate for these models: H2 on the surface is a 2-D gas with lifetime tau; and H2 on the surface is a 2-D liquid undergoing Brownian motion (diffusion) with surface lifetime tau.

Coffman, Robert E.↗
DOE OSTI2020

Improved single-particle phase-space distributions for viscous fluid dynamic models of relativistic heavy ion collisions

Comparison of hydrodynamic calculations with experimental data inevitably requires a model for converting the fluid to particles. For shear viscous fluids, several different conversion models have been proposed, such as the quadratic Grad corrections, the Strickland-Romatschke (SR) ansatz, self-consistent shear corrections from linearized kinetic theory, or corrections from the relaxation time approach. We show, via comparison to nonlinear 2 → 2 kinetic theory evolution, that even for low specific shear viscosities 0.03 ≲ $\textit{η/s}$ ≲ 0.2 , these four models have varying accuracy and still significant errors in reproducing particle phase space densities from hydrodynamic fields. Moreover, we demonstrate that the overall reconstruction error of additive shear viscous $f = f_{eq} + δf$ models dramatically reduces by up to one order of magnitude, if one ensures through exponentiation that $\textit{f}$ is always positive. Further, we also illustrate how even more accurate viscous $\textit{δf}$ models can be constructed by incorporating the first time derivatives of hydrodynamic fields to account for the past evolution of the system. Such time derivatives are readily available in hydrodynamic simulations, though usually not included in the output. Though our comparisons are limited to a one-component massless system undergoing a (0 + 1)-dimensional (0 + 1D) longitudinal boost-invariant expansion, we expect that the improved models will be useful in 2 + 1D and 3 + 1D hydrodynamic studies as well.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag 0 , Bi 0 , Cu 0 , or Sn 0 Particles

The capture of radioiodine from nuclear processes and the mitigation of environmental release are important topic areas of research. Some of the more commonly employed chemisorption-type iodine scavengers reported in the literature are based on metal-exchanged porous sorbents such as Ag-zeolites or metal-functionalized aerogels and xerogels. However, another option is to use zero-valent metals directly that have known high affinities for iodine gas [i.e., I2(g)]. In this study, fine metal particles of Ag0, Bi0, Cu0, and Sn0 were embedded in porous polyacrylonitrile (PAN) substrates at 75 mass% metal loadings within the form of ellipsoidal beads with maximum diameters of ~2–3 mm. These composite beads showed extremely high iodine loadings that are directly related to the metal particle loadings. The X-ray diffraction (XRD) analyses of Ag0, Bi0, Cu0, and Sn0 particles as well as metal-PAN composite beads reacted with iodine gas at 120 ± 1 °C showed phases of AgI, BiI3, CuI, and SnI4, respectively. For the Ag-PAN, Cu-PAN, and Sn-PAN beads, no other crystalline peaks were observed in XRD for unreacted metal or oxidized metals after 48 h in saturated I2(g) at 120 ± 1 °C, whereas unreacted metallic Bi0 was observed within the Bi-PAN composites. However, after a 72 h exposure at 120 ± 1 °C, both the Bi0 particles and the Bi-PAN composites showed full conversion from Bi0 to BiI3 with XRD. Comparisons between mass uptake data and X-ray absorption spectroscopy were used to better understand the phase distribution of the Bi phases present in the Bi-PAN+I composites. The iodine loadings (mg iodine per g sorbent, or qe) for these materials were 1120 (Ag-Particle), 1382 (Bi-Particle-72h), 1033 (Cu-Particle), 3000 (Sn-Particle), 753 (Ag-PAN), 1012 (Bi-PAN-72h), 1457 (Cu-PAN), and 1669 (Sn-PAN). It is possible that inexpensive sorbents such as these could be deployed to help limit or prevent release of radioiodine to the environment.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Separation, Recovery and Upgrading of 2,3-Butanediol from Fermentation Broth

2,3-Butanediol (BDO) is a bio-derived building block available from biomass through biochemical methods in high titers (>120 g L-1) making it an attractive target for production and further upgrading to chemical products and fuels such as sustainable aviation fuel. A key challenge to enable the adoption of BDO as a precursor is the effective separation and isolation of this molecule from the fermentation broth. 2,3-Butanediol has a boiling point higher than that of water (177 degrees C), and as a consequence, separation via distillation methods is an energy-intensive and therefore costly approach. We have improved the BDO separation through conversion to a 1,3-dioxolane directly in fermentation broth via reaction with bio-derived aldehydes catalyzed by a solid acid catalyst. The resulting dioxolane phase separates from the fermentation broth, allowing for easy decantation and isolation in >90% isolated yield. Isolated dioxolane can be used directly as a compression iginition fuel, trans-acetalized to recover high-purity BDO or used directly in a catalytic process as a BDO synthon to produce methyl ethyl ketone with aldehyde recovery in near quantitative yield.

aviation fuel↗
NASA NTRS1989

Direct conversion technology

The overall objective of the Direct Conversion Technology task is to develop an experimentally verified technology base for promising direct conversion systems that have potential application for energy conservation in the end-use sectors. This report contains progress of research on the Alkali Metal Thermal-to-Electric Converter (AMTEC), and on the Two-Phase Liquid-Metal Magnetohydrodynamic Electrical Generator (LMMHD) for the period January 1, 1989 through December 31, 1989. Research on these concepts was initiated during October 1987. Reports prepared on previous occasions contain discussions on the following other direct conversion concepts: thermoelectric, pyroelectric, thermionic, thermophotovoltaic, thermoacoustic, thermomagnetic, thermoelastic (nitinol heat engines); and also, more complete discussions of AMTEC and LMMHD systems.

Massier, Paul F.↗
DOE OSTI2022

High-efficiency second harmonic generation of blue light on thin-film lithium niobate

The strength of interactions between photons in a χ (2) nonlinear optical waveguide increases at shorter wavelengths. These larger interactions enable coherent spectral translation and light generation at a lower power, over a broader bandwidth, and in a smaller device: all of which open the door to new technologies spanning fields from classical to quantum optics. Stronger interactions may also grant access to new regimes of quantum optics to be explored at the few-photon level. One promising platform that could enable these advances is thin-film lithium niobate (TFLN), due to its broad optical transparency window and possibility for quasi-phase matching and dispersion engineering. In this Letter, we demonstrate second harmonic generation of blue light on an integrated thin-film lithium niobate waveguide and observe a conversion efficiency of η 0 = 33, 000%/W- cm 2 , significantly exceeding previous demonstrations.

Park, Taewon↗
NASA NTRS1977

Design and calculated performance and cost of the ECAS Phase II open cycle MHD power generation system

A 2000 MWe MHD/steam plant for central station applications has been designed and costed as part of the Energy Conversion Alternatives Study (ECAS). This plant is fueled by Illinois No. 6 coal, rejects heat through mechanical draft wet cooling towers, and includes coal processing equipment, seed reprocessing, electrical inversion of the MHD generator output and emission controls to current EPA standards. It yields an estimated overall efficiency of 0.483 (7066 Btu/kWe-hr), a capital cost of $718 per kWe (1975 dollars), and a cost of electricity at 65% capacity factor of 32 mills per kWe-hr. If the assumed life and reliability could be achieved with these performance parameters, the MHD system should prove attractive.

Harris, L. P.↗
DOE OSTI2021

Integrated capture and conversion of CO 2 to methanol or methanol and glycol

A process for producing methanol includes combining a hydrogenation catalyst, hydrogen, and CO 2 with a condensed phase solution comprising an amine under conditions effective to form methanol and water. A process for coproduction of methanol and a glycol includes combining an epoxide, a hydrogenation catalyst, hydrogen, and CO 2 with a condensed phase solution comprising an amine under conditions effective to form methanol and a glycol.

Kothandaraman, Jotheeswari↗