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Results for “multifunctionality”

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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

ReaxFF Simulations of Laser-Induced Graphene (LIG) Formation for Multifunctional Polymer Nanocomposites

Irradiation of polymer films by a CO 2 infrared laser under ambient conditions converts the polymer into porous graphene or laser-induced graphene (LIG). In this work, we simulate the formation of LIG from five different commercially available polymers using reactive molecular dynamics. We determined that the molecular structure of the parent polymer has a significant effect on the final graphitic structure. CO is liberated during the initial part of the LIG formation process when the polymer is converted into an amorphous structure, while H 2 is evolved steadily as the amorphous structure is converted to an ordered graphitic structure. The LIG structure has out-of-plane undulations and bends due to a significant number of 5- and 7-member carbon rings present throughout the structure. We find that the simulated molecular structure compares well with recent experimental observations from the literature. We also demonstrate that the yield of LIG is higher in inert conditions, compared to environments with oxygen. Polybenzimidazole-derived LIG has the highest surface area and yield among the five polymers examined. These findings provide knowledge of LIG formation mechanisms that can be leveraged for bulk LIG applications such as sensors, electrocatalysts, microfluidics, and targeted heating for welding polymers.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Multifunctional GdVO 4 : Eu core–shell nanoparticles containing 225 Ac for targeted alpha therapy and molecular imaging

Gadolinium vanadate nanoparticles (NPs) doped with europium, in concentrations between 5–40%, were synthesized via an aqueous route to prove their multimodal imaging functionalities and their performance as radionuclide carriers for targeted alpha therapy. Core–shell Gd 0.8 Eu 0.2 VO 4 NPs were doped with the α-emitting actinium-225 to assess the in vitro retention of 225 Ac and its decay daughters; francium-221 and bismuth-213. Gd 0.8 Eu 0.2 VO 4 core–shell NPs were obtained using a precipitation synthesis route having a tetragonal system, a spherical morphology, and a uniform particle size distribution. Gd 0.8 Eu 0.2 VO 4 core–shell NPs displayed the characteristic intense emission at 618 nm (red) and paramagnetic behavior of Eu and Gd cations, respectively. Partial retention of radionuclides was obtained with Gd 0.8 Eu 0.2 VO 4 core NPs, while deposition of two nonradioactive Gd 0.8 Eu 0.2 VO 4 shells significantly decreased the leakage of both 225 Ac and 221 Fr. As a result, the luminescence and magnetic functionalities as well as radionuclide retention capabilities of Gd 0.8 Eu 0.2 VO 4 core–shell NPs demonstrate their potential for biomedical applications.

gadolinium and europium vanadate↗
DOE OSTI2019

Limits of multifunctionality in tunable networks

Nature is rife with networks that are functionally optimized to propagate inputs to perform specific tasks. Whether via genetic evolution or dynamic adaptation, many networks create functionality by locally tuning interactions between nodes. Here we explore this behavior in two contexts: strain propagation in mechanical networks and pressure redistribution in flow networks. By adding and removing links, we are able to optimize both types of networks to perform specific functions. We define a single function as a tuned response of a single “target” link when another, predetermined part of the network is activated. Using network structures generated via such optimization, we investigate how many simultaneous functions such networks can be programed to fulfill. We find that both flow and mechanical networks display qualitatively similar phase transitions in the number of targets that can be tuned, along with the same robust finite-size scaling behavior. We discuss how these properties can be understood in the context of constraint–satisfaction problems.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Moving to Sustainable Metals: Multifunctional Ligands in Catalytic, Outer Sphere C-H, N-H and O-H Activation

Much of our work during this grant period has emphasized green chemistry and sustainability. For example, we were able to convert glycerine, a waste byproduct of biodiesel production, into lactic acid, a compound with numerous applications, notably in the food and cosmetics industry, as well as being a source material for a biodegradable plastic. This work required a catalyst, that ceases to work after a certain lapse of time. We were able to identify the way in which this deactivation occurs by identifying some of the metal catalyst deactivation products. These proved to be multimetallic clusters containing up to six metals and up to 14 hydrogen atoms. Both the catalytic reaction itself and the deactivation structures are novel and unexpected. We have previously proposed that nitrogen heterocycles could be good energy carriers in a low CO 2 future world. In another part of our study, we found catalysts for introduction of hydrogen, an energy carrier that is hard to store, into nitrogen heterocycles. The mechanism of this process proved to be unusual in that the catalyst transfers the H 2 to the heterocycle in the form of H + and H - , first transferring the H + and only then the H - . In a third area of study, some of our compounds, originally prepared for DOE catalysis purposes, also proved useful in hydrocarbon oxidation and in water oxidation. The latter is important in solar-to-fuel work, because, by analogy with natural photosynthesis, the goal of the Yale Solar Group of four PIs is to convert sunlight to hydrogen and oxygen, which requires water splitting catalysts. The catalysts that proved useful mediate the latter reaction: water oxidation to oxygen. In a more technical study, we developed methods for distinguishing the case where catalysis is mediated by a soluble catalyst from cases where catalysis arises from a deposit of finely divided solid. One particular application involved electrocatalysis, where catalysis is driven by application of a voltage to electrodes dipped in the reactant mixture. We measured the mass increase of an electrode as material is deposited, and were able to see how this process is affected by the voltage supplied to the electrode. Our work continues to be well cited and we often receive requests for information or samples from fellow researchers.

08 HYDROGEN↗
NASA NTRS2015

Testing and Evaluation of Multifunctional Smart Coatings

A smart coating system, based on pH sensitive microcontainers (microparticles and microcapsules) has been developed. Various corrosion inhibitors have been encapsulated and incorporated into commercial and formulated coatings to test the functionality imparted on the coating by the incorporation of the inhibitor microcontainers. Coated carbon steel and aluminum alloy panels were tested using salt immersion, salt fog, and coastal atmospheric exposure conditions. This paper provides the details on coating sample preparation, evaluation methods, as well as test results of the inhibiting function of smart coatings.

Testing and Evaluation↗
NASA NTRS2016

Aerogel Hybrid Composite Materials: Designs and Testing for Multifunctional Applications

This webinar will introduce the broad spectrum of aerogel composites and their diverse performance properties such as reduced heat transfer to energy storage, and expands specifically on the aerogel/fiber laminate systems and testing methodologies. The multi-functional laminate composite system, AeroFiber, and its construction is designed by varying the type of fiber (e.g. polyester, carbon, Kevlar®, Spectra® or Innegral(TradeMark) and combinations thereof), the aerogel panel type and thickness, and overall layup configuration. The combination and design of materials may be customized and tailored to achieve a range of desired properties in the resulting laminate system. Multi-functional properties include structural strength, impact resistance, reduction in heat transfer, increased fire resistance, mechanical energy absorption, and acoustic energy dampening. Applications include aerospace, aircraft, automotive, boating, building and construction, lightweight portable structures, liquefied natural gas, cryogenics, transportation and energy, sporting equipment, and military protective gear industries.

Hybrid↗
NASA NTRS1996

Multifunction Automated Crawling System (MACS)

Nondestructive Evaluation (NDE) instruments and sensors are becoming smaller with enhanced computer controlled capability and increasingly used commercially available hardware and software.

Multifunction↗
DOE OSTI2018

Enhanced Interfacial Stability of Hybrid-Electrolyte Lithium-Sulfur Batteries with a Layer of Multifunctional Polymer with Intrinsic Nanoporosity

We report that the use of lithium-ion conductive solid electrolytes offers a promising approach to address the polysulfide-shuttle and the lithium-dendrite problems in lithium-sulfur (Li-S) batteries. One critical issue with the development of solid-electrolyte Li-S batteries is the electrode-electrolyte interfaces. We present herein a strategic approach by employing a thin layer of a polymer with intrinsic nanoporosity (PIN) on a Li + -ion conductive solid electrolyte, which significantly enhances the ionic interfaces between the electrodes and the solid electrolyte. Among the various types of Li + -ion solid electrolytes, NASICON-type Li 1+x Al x Ti 2-x (PO 4 ) 3 (LATP) offers advantages in terms of Li + -ion conductivity, stability in ambient environment, and practical viability. However, LATP is susceptible to reaction with both the Li-metal anode and polysulfides in Li-S batteries due to the presence of easily reducible Ti 4+ ions in it. The coating with a thin layer of PIN presented in this study overcomes the above issues. At the negative-electrode side, the PIN layer prevents the direct contact of Li-metal with the LATP solid electrolyte, circumventing the reduction of LATP by Li metal. Lastly, at the positive electrode side, the PIN layer prevents the migration of polysulfides to the surface of LATP, preventing the reduction of LATP by polysulfides.

25 ENERGY STORAGE↗
DOE OSTI2017

Metal Thio- and Selenophosphates as Multifunctional van der Waals Layered Materials

Since the discovery of Dirac physics in graphene, research in 2D materials has exploded with the aim of finding new materials and harnessing their unique and tunable electronic and optical properties. The follow-on work on 2D dielectrics and semiconductors has led to the emergence and development of hexagonal boron nitride, black phosphorus, and transition metal disulfides. However, the spectrum of good insulating materials is still very narrow. Likewise, 2D materials exhibiting correlated phenomena such as superconductivity, magnetism, and ferroelectricity have yet to be developed or discovered. These properties will significantly enrich the spectrum of functional 2D materials, particularly in the case of high phase-transition temperatures. They will also advance a fascinating fundamental frontier of size and proximity effects on correlated ground states. In this work, a broad family of layered metal thio(seleno)phosphate materials that are moderate- to wide-bandgap semiconductors with incipient ionic conductivity and a host of ferroic properties are reviewed. It is argued that this material class has the potential to merge the sought-after properties of complex oxides with electronic functions of 2D and quasi-2D electronic materials, as well as to create new avenues for both applied and fundamental materials research in structural and magnetic correlations.

2D materials↗
DOE OSTI2021

Self‐Assembled Metal–Dielectric Hybrid Metamaterials in Vertically Aligned Nanocomposite Form with Tailorable Optical Properties and Coupled Multifunctionalities

Metal–dielectric hybrid metamaterials have attracted increasing research interest in recent years because of their novel optical properties and promising applications in the fields of electronic and photonic devices. Dielectric permittivity is a key parameter that strongly influences the optical properties of materials. By self‐assembling the metallic and dielectric components in a pillar‐in‐matrix structure, a strong anisotropic structure forms and results in opposite signs of permittivity components (i.e., ε || > 0 and ε ⊥ < 0, or vice versa) and exotic optical responses including hyperbolic dispersion in the visible to near‐infrared region. Herein, the main approaches of tuning the permittivity in self‐assembled metal–dielectric vertically aligned nanocomposite (VAN) thin films are reviewed, including tuning the metal pillar density and geometry, film strain state and background pressure during growth, and seeking other metal‐free and complex structure designs. Future research directions are also proposed, including unique approaches to improve their thermal stability, integrate on flexible substrates toward wearable device fabrication, and explore real‐time tunable metamaterials.

Zhang, Di↗
DOE OSTI2015

Multifunctional Hydrogels with Reversible 3D Ordered Macroporous Structures

Three-dimensionally ordered macroporous (3DOM) hydrogels prepared by colloidal crystals templating display highly reversible shape memory properties, as confirmed by indirect electron microscopy imaging of their inverse replicas and direct nanoscale resolution X-ray microscopy imaging of the hydrated hydrogels. Modifications of functional groups in the 3DOM hydrogels result in various materials with programmed properties for a wide range of applications.

36 MATERIALS SCIENCE↗