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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Membranes having aligned 1-D nanoparticles in a matrix layer for improved fluid separation

Membranes for fluid separation are disclosed. These membranes have a matrix layer sandwiched between an active layer and a porous support layer. The matrix layer includes 1-D nanoparticles that are vertically aligned in a porous polymer matrix, and which substantially extend through the matrix layer. The active layer provides species-specific transport, while the support layer provides mechanical support. A matrix layer of this type has favorable surface morphology for forming the active layer. Furthermore, the pores that form in the matrix layer tend to be smaller and more evenly distributed as a result of the presence of aligned 1-D nanoparticles. Improved performance of separation membranes of this type is attributed to these effects.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Compositions for directed alignment of conjugated polymers

Conjugated polymers (CPs) achieve directed alignment along an applied flow field and a dichroic ratio of as high as 16.67 in emission from well-aligned thin films and fully realized anisotropic optoelectronic properties of CPs in field-effect transistor (FET).

36 MATERIALS SCIENCE↗
DOE OSTI2017

Low temperature superconductor and aligned high temperature superconductor magnetic dipole system and method for producing high magnetic fields

A dipole-magnet system and method for producing high-magnetic-fields, including an open-region located in a radially-central-region to allow particle-beam transport and other uses, low-temperature-superconducting-coils comprised of low-temperature-superconducting-wire located in radially-outward-regions to generate high magnetic-fields, high-temperature-superconducting-coils comprised of high-temperature-superconducting-tape located in radially-inward-regions to generate even higher magnetic-fields and to reduce erroneous fields, support-structures to support the coils against large Lorentz-forces, a liquid-helium-system to cool the coils, and electrical-contacts to allow electric-current into and out of the coils. The high-temperature-superconducting-tape may be comprised of bismuth-strontium-calcium-copper-oxide or rare-earth-metal, barium-copper-oxide (ReBCO) where the rare-earth-metal may be yttrium, samarium, neodymium, or gadolinium. Advantageously, alignment of the large-dimension of the rectangular-cross-section or curved-cross-section of the high-temperature-superconducting-tape with the high-magnetic-field minimizes unwanted erroneous magnetic fields. Alignment may be accomplished by proper positioning, tilting the high-temperature-superconducting-coils, forming the high-temperature-superconducting-coils into a curved-cross-section, placing nonconducting wedge-shaped-material between windings, placing nonconducting curved-and-wedge-shaped-material between windings, or by a combination of these techniques.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Method of manufacturing high volumetric density electrodes from self-aligning fiber powders

An electrode and a related method of manufacture are provided. The electrode includes a self-aligning active material having short fiber powders with a cylindrical morphology to increase the packing density from 0.74 to nearly 0.91. The short fiber powders self-align during a slurring coating process as a result of shear forces between a die and a foil. The resulting coating includes parallel short fibers in a closed packed arrangement, providing an increased volumetric capacity of at least approximately 17%.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Preventing hot-gas ingestion by film-cooling jet via flow-aligned blockers

A system for cooling includes a surface to be cooled, at least one film-cooling hole within the surface for allowing a film cooling jet of coolant to reach the surface, each of the at least one film-cooling hole having a diameter and at least two spaced apart flow-aligned blockers positioned downstream of the at least one-film cooling hole, each of the flow-aligned blockers extending upwardly from the surface to assist in preventing hot-gas entrainment and increasing adiabatic effectiveness by confining coolant flow downstream of the at least one film-cooling hole between the blockers.

Shih, Tom I-P↗
DOE OSTI2019

X-ray beam alignment device and method

The present invention provides a bright, focused visible light source that is part of a visible light alignment assembly that is coupled to an X-ray generator. The visible light source projects a bright, focused visible light beam from the X-ray generator through a collimator and object or part to be radiographed and to a detector or film, just as a subsequent X-ray beam eventually is. This allows the operator to quickly and easily visually assess the eventual position and coverage or spread of the X-ray beam and align the X-ray generator, collimator, object or part to be radiographed, and/or detector or film, with a minimum of test radiographs.

Henry, Nathaniel Frederick↗
DOE OSTI2019

Continuous fabrication system and method for highly aligned polymer films

Process for continuous fabrication of highly aligned polymer films. A polymer-solvent solution is subjected to a high shear, high temperature, Couette flow to extrude a thin film having polymer chain disentanglement. The extruded thin film is frozen and the solvent is allowed to evaporate to form a dried film. The dried film is mechanically drawn using a constant force, adaptive-thickness drawing system to align polymer molecular chains through plastic deformation. A suitable polymer is ultra-high molecular weight polyethylene.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Self-aligning swaging punch and method for swaging

A self-aligning swaging punch is provided for adjoining together a pin and a workpiece having a pinhole. The swaging punch comprises a shaft and a tip having an open-ended cavity. The shaft transfers an axial force from a press or hammer to the tip. The tip transfers the axial force from the shaft to a top surface of the workpiece near the pinhole. The tip may be spherical in shape for evenly deforming the workpiece near the upper edge of the pinhole. The open-ended cavity receives the pin therein and allows the pin to extend at least partially into the open-ended cavity while the tip contacts the workpiece. The open-ended cavity also ensures that the swaging punch is aligned with the pinhole and perpendicular to the surface of the workpiece when the pin is inserted into the pinhole such that the workpiece evenly deforms and presses against the pin.

42 ENGINEERING↗
DOE OSTI2020

Magnetic field alignment of emulsions to produce porous articles

The use of magnetic fields in the production of porous articles is generally described. Certain embodiments are related to methods of producing porous articles in which magnetic fields are applied to an emulsion to align emulsion droplets. In some embodiments, after the emulsion droplets have been aligned, the emulsion droplets and/or the medium surrounding the emulsion droplets can be removed to leave behind a porous article. According to certain embodiments, polyvinyl alcohol can be used, for example, to stabilize the emulsion droplets and/or bind together components of the porous article. In some embodiments, water-soluble liquid alcohol can be used, for example, to stabilize the suspension of electronically conductive material within a phase of the emulsion.

36 MATERIALS SCIENCE↗
DOE OSTI2020

A Dynamic Amplitude-Correcting Gradient Estimation Technique to Align X-ray Focusing Optics

High-brightness X-rays, as produced at synchrotrons and X-ray free electron laser (XFEL) facilities, are used to characterize materials in a variety of scientific experiments. In most cases, effective use of the high-energy light requires precisely-aligned focusing optics; one example being a compound refractive lens (CRL). To align a CRL, the position and rotation must be optimized along four axes. In practice, this is a labor-intensive, time-consuming manual process that can monopolize scarce experimental time at the necessary X-ray facilities. Models of the expected Xray transmission function suggest that this task can be automated; however, the temporally-varying intensity at X-ray free electron laser facilities preclude the direct use of standard implementations of optimization solvers such as steepest descent algorithms. In this paper, we propose a novel technique to estimate the gradient of noisy functions with temporally-varying amplitudes. We construct this dynamicamplitude correction by systematically sampling a fixed central location within the standard finite difference stencil, accounting for the observed changes in time, and normalizing the difference quotients against those fluctuations. In addition to a rigorous error analysis of the sampling technique, we demonstrate its efficacy in stochastic descent optimization methods. Further, we demonstrate how this approach may be implemented to optimize X-ray focusing optics at synchrotrons or XFEL facilities

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Crankcase ventilation system with dead space alignment sleeves

A cylinder aligning sleeve and adapter plate for use within an internal combustion engine. The sleeve includes apertures placed contiguously with holes within the adapter plate to form a flow passage through the dead space between compression and crosshead pistons. The flow passage exits to a vent line where gas detection may occur along with safe venting of any gas detected. The sleeve serves to ensure concentric alignment of the compression cylinder with the engine block bore.

Alvarado, Caleb A.↗
DOE OSTI2014

Alignment of the 12 Gev CEBAF Accelerator

Alignment of the 12 Gev CEBAF Accelerator Jefferson lab has just completed an upgrade to its CEBAF accelerator which allows for an increase in the energy of delivered beam from 6Gev to 12 Gev. The enhancements to the accelerator have included the addition of 10 new high performance cryomodules, and the removal, upgrade and refurbishment of almost 300 existing transport magnets. Outside of the main accelerator, a new experimental hall has been constructed, and the three existing halls are currently being upgraded to take advantage of the higher energies. For this project, a new survey network has been measured and almost every element in the accelerator has been re-aligned. Commissioning of the accelerator took place at the beginning of this year, during the course of which, it became apparent that there was a significant difference between the expected and the actual path length in the machine. This paper describes the measurements taken and analysis used to try and understand this situation.

Curtis, Christopher↗
DOE OSTI2024

SCITUNE: Aligning Large Language Models with Human-Curated Scientific Multimodal Instructions

Instruction finetuning is a popular paradigm to align large language models (LLM) with human intent. Despite its popularity, this idea is less explored in improving the LLMs to align existing foundation models with scientific disciplines, concepts and goals. In this work, we present SciTune as a tuning framework to improve the ability of LLMs to follow scientific multimodal instructions. To test our methodology, we use a human-generated scientific instruction tuning dataset and train a large multimodal model LLaMA-SciTune that connects a vision encoder and LLM for science-focused visual and language understanding. LLaMA-SciTune significantly outperforms the state-of-the-art models in the generated figure types and captions in multiple scientific multimodal benchmarks. In comparison to the models that are fine-tuned with machine generated data only, LLaMA-SciTune surpasses human performance on average and in many sub-categories on the ScienceQA benchmark.

• Artificial intelligence (AI) / machine learning ↗
DOE OSTI2018

Nanoscale Artificial Plasmonic Lattice in Self-Assembled Vertically Aligned Nitride-Metal Hybrid Metamaterials

Nanoscale metamaterials exhibit extraordinary optical properties and are proposed for various technological applications. Here, a new class of novel nanoscale two–phase hybrid metamaterials is achieved by combining two major classes of traditional plasmonic materials, metals (e.g., Au) and transition metal nitrides (e.g., TaN, TiN, and ZrN) in an epitaxial thin film form via the vertically aligned nanocomposite platform. By properly controlling the nucleation of the two phases, the nanoscale artificial plasmonic lattices (APLs) consisting of highly ordered hexagonal close packed Au nanopillars in a TaN matrix are demonstrated. More specifically, uniform Au nanopillars with an average diameter of 3 nm are embedded in epitaxial TaN platform and thus form highly 3D ordered APL nanoscale metamaterials. Novel optical properties include highly anisotropic reflectance, obvious nonlinear optical properties indicating inversion symmetry breaking of the hybrid material, large permittivity tuning and negative permittivity response over a broad wavelength regime, and superior mechanical strength and ductility. Furthermore, the study demonstrates the novelty of the new hybrid plasmonic scheme with great potentials in versatile material selection, and, tunable APL spacing and pillar dimension, all important steps toward future designable hybrid plasmonic materials.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Theoretical Investigation of the Oxygen Reduction Reaction over Platinum Catalysts Supported by Multi-Edged Vertically Aligned Carbon Nanofiber for Electrocatalyst Preparation

Vertically aligned carbon nanofibers (VACNFs) are promising supports for oxygen reduction reaction (ORR) electrocatalysts in fuel cells. Although experimentally these catalytic systems have shown great potential, there is lack of molecular understanding of the catalytic sites and reaction mechanisms. This work investigated the origin of the ORR reactivities of the platinum catalysts on multi-edged VACNFs (Pt/VACNF) using a multiscale modeling approach combining Density Functional Theory (DFT) and classical Molecular Dynamics (MD) simulations. Based on the ReaxFF potential, here all nanoscale Pt particles (Pt 55 , P 100 , and Pt 147 ) are stabilized by the open edges located axially along the VACNF walls. The calculated first-shell coordination numbers, CN, of surface Pt atoms are 6.63, 7.27, and 7.85, respectively, suggesting that the percentage of low coordination sites increases as the particle size decreases. The adsorption energies of OOH, O, and OH on Pt-55 were systematically probed using DFT calculations. These adsorption energies retain a linear correlation against the generalized coordination numbers ($\overline{CN}$). For Pt nanoparticles supported on VACNF, we found that the OOH and OH bind stronger than on Pt (111) by 0.14 and 0.17 eV, respectively, which can hinder the ORR activity with lower limiting potential than Pt (111). Our theoretical prediction is in good agreement with the linear sweeping voltammetry that revealed a left shift of the half-wave potential.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

The crystal-crystal transition in hydrogenated ring-opened polynorbornenes: Tacticity, crystal thickening, and alignment

At a temperature T cc well below its melting point T m , hydrogenated ring-opened polynorbornene (hPN) is known to exhibit a crystal-crystal transition; above T cc , the hPN chains are rotationally disordered. This transition is examined in a series of hPNs polymerized with different Mo- and Ru-based catalysts, each of which imparts a slightly different tacticity to the polymer. T cc is found to correlate well with the ratio of meso to racemo dyads (m:r); small changes in m:r (from 0.8 to 1.1) are sufficient to raise T cc by nearly 20 °C. For the homogeneous Mo-based 'Schrock-type' catalyst examined, such a change in m:r is easily achieved by simply adding the reversibly binding ligand trimethylphosphine during polymerization. T cc approaches T m with increasing m:r, indicating that r dyads stabilize the rotationally disordered structure. When heated above T cc , hPN crystals thicken at a rate much greater than conventional three-dimensionally ordered crystals, but below the rates shown by the two-dimensional hexagonal (columnar) phase formed by some polymers, reflecting the intermediate level of order and chain mobility present in the high-temperature hPN crystal phase. Solid-state processing of hPN between T cc and T m yields highly aligned macroscopic specimens.

36 MATERIALS SCIENCE↗
DOE OSTI2018

The Basic Results of Alignment and Summary of Operations of the Main K-1000-60/3000 Turbine Unit with a Small Number of Bearings at the Bushehr Nuclear Power Plant

The results of vibration alignment and the first years of use of the prototype K-1000-60/3000-3 turbine unit of the Bushehr NPP in 2011 – 2016 are examined. As a result of conducting an extensive set of studies and actions, the claimed high-quality operating characteristics of the new design bearings that were used and the high degree of vibrational reliability of the turbine unit were confirmed, and these made it possible to ensure successful commissioning on a short timeline, despite the novelty of the design and the uniqueness of development of the majority of units, taking into account the integration of the equipment with the existing base and the condenser group. During the commissioning work, it was shown that this turbine unit is not inferior in any manner to turbine units of analogous power from other firms.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗