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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

An overview of process systems engineering approaches for process intensification: State of the art

Process intensification offers the potential to drastically reduce the energy consumption and cost of producing chemicals from both bulk and distributed feedstocks. This review article aims to offer an extensive survey on state-of-the-art process systems engineering (PSE) approaches for process intensification. From both academic and industrial perspectives, this paper provides an overview of the development of various process intensification technologies, specifically those under the categories of separation, reaction, hybrid reaction/separation, and alternative energy sources. A current status analysis in the areas of modeling and simulation is then provided. An indicative list of PSE publications specialized on process intensification is presented to illustrate the progresses made so far towards the deployment of novel process intensification technologies. We also highlight some recent advances for the modeling, design, and synthesis of intensified systems, as well as for the assessment of their controllability/operability/safety performance. As a result, key open questions in these areas include: (i) how to systematically derive intensified designs, and (ii) how to ensure the operability and optimality of the derived intensified structures while delivering their expected functionality.

42 ENGINEERING↗
DOE OSTI2014

Role of the interface on radiation damage in the SrTiO{sub 3}/LaAlO{sub 3} heterostructure under Ne{sup 2+} ion irradiation

We systematically investigated the microstructural evolution of heteroepitaxial SrTiO{sub 3} (STO) thin films grown on a single crystal LaAlO{sub 3} (LAO) (001) substrate, focusing on the response of the STO/LAO interface to Ne{sup 2+} irradiation at room temperature. Cross sectional transmission electron microscope (TEM) analysis reveals that the LAO crystal amorphizes first after a relatively low dose of damage followed by the amorphization of the STO film after irradiation to a higher dose. While the critical dose to amorphize differs between each material, amorphization begins at the interface and proceeds outward in both cases. Thus, a crystalline/amorphous interface first forms at the STO/LAO interface by a dose of 1 dpa, and then an amorphous/amorphous interface forms when the dose reaches 3 dpa. Scanning TEM and x-ray energy dispersive spectroscopy indicate no significant heavy cation elemental diffusion, though electron energy loss spectroscopy reveals a redistribution of oxygen across the film/substrate interface after Ne{sup 2+} irradiation. Atomistic calculations are used to interpret the experimental findings in terms of the defect properties in each of the two component phases.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Precursor recommendation for inorganic synthesis by machine learning materials similarity from scientific literature

Synthesis prediction is a key accelerator for the rapid design of advanced materials. However, determining synthesis variables such as the choice of precursor materials is challenging for inorganic materials because the sequence of reactions during heating is not well understood. In this work, we use a knowledge base of 29,900 solid-state synthesis recipes, text-mined from the scientific literature, to automatically learn which precursors to recommend for the synthesis of a novel target material. The data-driven approach learns chemical similarity of materials and refers the synthesis of a new target to precedent synthesis procedures of similar materials, mimicking human synthesis design. When proposing five precursor sets for each of 2654 unseen test target materials, the recommendation strategy achieves a success rate of at least 82%. Our approach captures decades of heuristic synthesis data in a mathematical form, making it accessible for use in recommendation engines and autonomous laboratories.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Understanding the Fluorination of Disordered Rocksalt Cathodes through Rational Exploration of Synthesis Pathways

Here, we have designed and tested several synthesis routes targeting a highly fluorinated disordered rocksalt (DRX) cathode, Li 1.2 Mn 0.4 Ti 0.4 O 1.6 F 0.4 , with each route rationalized by thermochemical analysis. Precursor combinations were screened to raise the F chemical potential and avoid the formation of LiF, which inhibits fluorination of the targeted DRX phase. MnF 2 was used as a reactive source of F, and Li 6 MnO 4 , LiMnO 2 , and Li 2 Mn 0.33 Ti 0.66 O 3 were tested as alternative Li sources. Each synthesis procedure was monitored using a multi-modal suite of characterization techniques including X-ray diffraction, nuclear magnetic resonance, thermogravimetric analysis, and differential scanning calorimetry. From the resulting data, we advance the understanding of oxyfluoride synthesis by outlining the key factors limiting F solubility. At low temperatures, MnF 2 consistently reacts with the Li source to form LiF as an intermediate phase, thereby trapping F in strong Li-F bonds. LiF can react with Li 2 TiO 3 to form a highly lithiated and fluorinated DRX (Li 3 TiO 3 F); however, MnO is not easily incorporated into this DRX phase. Although higher temperatures typically increase solubility, the volatility of LiF above its melting point (848 °C) inhibits fluorination of the DRX phase. Based on these findings, metastable synthesis techniques are suggested for future work on DRX fluorination.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Design of radiation resistant metallic multilayers for advanced nuclear systems

Helium implantation from transmutation reactions is a major cause of embrittlement and dimensional instability of structural components in nuclear energy systems. Development of novel materials with improved radiation resistance, which is of the utmost importance for progress in nuclear energy, requires guidelines to arrive at favorable parameters more efficiently. Here, we present a methodology that can be used for the design of radiation tolerant materials. We used synchrotron X-ray reflectivity to nondestructively study radiation effects at buried interfaces and measure swelling induced by He implantation in Cu/Nb multilayers. The results, supported by transmission electron microscopy, show a direct correlation between reduced swelling in nanoscale multilayers and increased interface area per unit volume, consistent with helium storage in Cu/Nb interfaces in forms that minimize dimensional changes. In addition, for Cu/Nb layers, a linear relationship is demonstrated between the measured depth-dependent swelling and implanted He density from simulations, making the reflectivity technique a powerful tool for heuristic material design.

36 MATERIALS SCIENCE↗
NASA NTRS1991

Synthesis of structural/control systems robust with respect to design variable tolerances

A methodology is presented for the synthesis of control augmented structures which can be modeled as an assemblage of beam, truss, and nonstructural mass elements augmented by a robust noncollocated direct output feedback control system. The control system is robust in the sense that it can tolerate manufacturing and realization errors. The robust control system is synthesized using a constraint buffering technique in conjunction with the approximation concepts approach to system synthesis. All of the design constraints on the system, including the dynamic stability, are buffered by a nonlinear quantity that is a function of acceptable tolerances on the design variables and the sensitivity of the constraints to changes in these design variables. Numerical results which illustrate the effectiveness of the method presented are given.

Thomas, H. L.↗
NASA NTRS1997

Enhanced Attitude Control Experiment for SSTI Lewis Spacecraft

The enhanced attitude control system experiment is a technology demonstration experiment on the NASA's small spacecraft technology initiative program's Lewis spacecraft to evaluate advanced attitude control strategies. The purpose of the enhanced attitude control system experiment is to evaluate the feasibility of designing and implementing robust multi-input/multi-output attitude control strategies for enhanced pointing performance of spacecraft to improve the quality of the measurements of the science instruments. Different control design strategies based on modern and robust control theories are being considered for the enhanced attitude control system experiment. This paper describes the experiment as well as the design and synthesis of a mixed H(sub 2)/H(sub infinity) controller for attitude control. The control synthesis uses a nonlinear programming technique to tune the controller parameters and impose robustness and performance constraints. Simulations are carried out to demonstrate the feasibility of the proposed attitude control design strategy. Introduction

Maghami, Peoman G.↗
DOE OSTI2018

Controllable synthesis of CNT@ZnO composites with enhanced electrochemical properties for lithium-ion battery

Highlights: • The optimized CNT@ZnO composites deliver 709.2 mAh g{sup −1} at 100 mA g{sup −1} after 50 cycles. • The structure of CNT@ZnO composites has the advantages of both ZnO and MWCNTs. • The optimized CNT@ZnO composites are promising anode materials for LIBs. - Abstract: The design and synthesis of anode materials with novel structures are one of crucial issues for developing next-generation lithium-ion battery. In this work, carbon nanotube@zinc oxide (CNT@ZnO) composites are synthesized by a liquid-phase method using CNTs as a conductive support. The design of CNT@ZnO composites combines the advantages of both ZnO nanoparticles and CNTs. The optimized CNT@ZnO composite exhibits the superior cycling and rate performance. It could deliver a discharge capacity of 709.2 mAh g{sup −1} at 100 mA g{sup −1} after 50 cycles. The electrochemical results indicate that the as-synthesized CNT@ZnO composite is superior in enhancing the electrochemical performance of ZnO-based anode materials.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2014

High Methane Storage Capacity in Aluminum Metal-Organic Frameworks

The use of porous materials to store natural gas in vehicles requires large amounts of methane per unit of volume. Here we report the synthesis, crystal structure and methane adsorption properties of two new aluminum metal–organic frameworks, MOF-519 and MOF-520. Both materials exhibit permanent porosity and high methane volumetric storage capacity: MOF-519 has a volumetric capacity of 200 and 279 cm 3 cm –3 at 298 K and 35 and 80 bar, respectively, and MOF-520 has a volumetric capacity of 162 and 231 cm 3 cm –3 under the same conditions. Furthermore, MOF-519 exhibits an exceptional working capacity, being able to deliver a large amount of methane at pressures between 5 and 35 bar, 151 cm 3 cm –3 , and between 5 and 80 bar, 230 cm 3 cm –3 .

Gándara, Felipe↗
DOE OSTI2014

A fast grain-growth mechanism revealed in nanocrystalline ceramic oxides

Grain growth issues in nanocrystalline ceramic oxides render their highly attractive properties practically unusable due to limited understanding of the underlying grain-growth mechanisms. Two conventional “slow” grain-growth mechanisms, i.e. curvature driven and grain-rotation driven, are shown to be thermally active, and the discovery of a “fast” disorder-driven mechanism is revealed using molecular dynamics simulation on nanocrystalline ceria, in conjunction with experimental observations. We show that this disorder mechanism drives the unexpected fast grain growth observed experimentally during synthesis and irradiation conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2021

A graph-based network for predicting chemical reaction pathways in solid-state materials synthesis

Abstract Accelerated inorganic synthesis remains a significant challenge in the search for novel, functional materials. Many of the principles which enable “synthesis by design” in synthetic organic chemistry do not exist in solid-state chemistry, despite the availability of extensive computed/experimental thermochemistry data. In this work, we present a chemical reaction network model for solid-state synthesis constructed from available thermochemistry data and devise a computationally tractable approach for suggesting likely reaction pathways via the application of pathfinding algorithms and linear combination of lowest-cost paths in the network. We demonstrate initial success of the network in predicting complex reaction pathways comparable to those reported in the literature for YMnO 3 , Y 2 Mn 2 O 7 , Fe 2 SiS 4 , and YBa 2 Cu 3 O 6.5 . The reaction network presents opportunities for enabling reaction pathway prediction, rapid iteration between experimental/theoretical results, and ultimately, control of the synthesis of solid-state materials.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Coordination Chemistry in the Structural and Functional Exploration of Actinide-Based Metal-Organic Frameworks

The coordination chemistry between inorganic and organic species can be optimally exemplified by metal–organic frameworks (MOFs), whose structures and functionalities can be rationally designed from these highly tunable building blocks. The high porosity, stability, and versatile functionalities of MOFs have attracted wide-spread attention from energy-related research and pollution remediation to biomedical applications. A unique and underexplored subset of these materials are MOFs based on actinide nodes; these MOFs have distinguished themselves as a unique platform for investigating the versatile oxidation states, reactivity, and coordination chemistry of actinides. Herein, we will focus on the rational design and synthesis of actinide-based MOFs under the general guidelines of coordination chemistry for their structural and functional explorations. The dimensionality, topology, and structures of actinide-based MOFs can be controlled by selecting pre-designed building blocks of actinide-based nodes and organic linkers with certain desired coordination geometries and functionalities. Furthermore, these unique actinide-based MOFs have shown promise for applications in nuclear waste mitigation, pollution control, and catalysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Solid-state dimer method for calculating solid-solid phase transitions

The dimer method is a minimum mode following algorithm for finding saddle points on a potential energy surface of atomic systems. Here, the dimer method is extended to include the cell degrees of freedom for periodic solid-state systems. Using this method, reaction pathways of solid-solid phase transitions can be determined without having to specify the final state structure or reaction mechanism. Example calculations include concerted phase transitions between CdSe polymorphs and a nucleation and growth mechanism for the A15 to BCC transition in Mo.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Design of Hollow Nanostructures for Energy Storage, Conversion and Production

Abstract Hollow nanostructures have shown great promise for energy storage, conversion, and production technologies. Significant efforts have been devoted to the design and synthesis of hollow nanostructures with diverse compositional and geometric characteristics in the past decade. However, the correlation between their structure and energy‐related performance has not been reviewed thoroughly in the literature. Here, some representative examples of designing hollow nanostructure to effectively solve the problems of energy‐related technologies are highlighted, such as lithium‐ion batteries, lithium‐metal anodes, lithium–sulfur batteries, supercapacitors, dye‐sensitized solar cells, electrocatalysis, and photoelectrochemical cells. The great effect of structure engineering on the performance is discussed in depth, which will benefit the better design of hollow nanostructures to fulfill the requirements of specific applications and simultaneously enrich the diversity of the hollow nanostructure family. Finally, future directions of hollow nanostructure design to solve emerging challenges and further improve the performance of energy‐related technologies are also provided.

Wang, Jiangyan↗
DOE OSTI2020

Biomimetic Rebuilding of Multifunctional Red Blood Cells: Modular Design Using Functional Components

The design and synthesis of artificial materials that mimic the structures, mechanical properties, and ultimately functionalities of biological cells remains a current holy grail of materials science. Here based on a silica cell bio-replication approach, we report the design and construction of synthetic rebuilt red blood cells (RRBCs) that fully mimic the broad properties of native RBCs: size, biconcave shape, deformability, oxygen carrying capacity, long circulation time. Four successive nano-scale processing steps: RBC bioreplication, layer-by-layer polymer deposition, and precision silica etching, followed by RBC ghost membrane vesicles fusion are employed for RRBC construction. A panel of physicochemical analyses including zeta potential measurement, fluorescence microscopy, and antibody-mediated agglutination assay proved the recapitulation of RBC shape, size, and membrane structure. Flow-based deformation studies carried out in a microfluidic blood capillary model confirrned the ability of RRBCs to deform and pass through small slits and reconstitute themselves in a manner comparable to native RBCs. Circulation studies of RRBCs conducted ex-ovo in a chick embryo and in vivo in a mouse model demonstrated the requirement of both deformability and native cell membrane surface to achieve long-term circulation. To confer additional non-native functionalities to RRBCs, we developed modular procedures in which to load functional cargos such as hemoglobin, drugs, magnetic nanoparticles, and ATP biosensors within the RRBC interior to enable various functions, including oxygen delivery, therapeutic drug delivery, magnetic manipulation, and toxin biosensing and detection. Taken together, RRBCs represent a class of long circulating RBC-inspired artificial hybrid materials with a broad range of potential applications.

59 BASIC BIOLOGICAL SCIENCES↗