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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

Assessment of Composite Delamination Self-Healing Via Micro-Encapsulation

Composite skin/stringer flange debond specimens manufactured from composite prepreg containing interleaf layers with a polymer based healing agent encapsulated in thin walled spheres were tested. As a crack develops and grows in the base polymer, the spheres fracture releasing the healing agent. The agent reacts with catalyst and polymerizes healing the crack. In addition, through-thickness reinforcement, in the form of pultruded carbon z-pins were included near the flange tips to improve the resistance to debonding. Specimens were manufactured with 14 plies in the skin and 10 plies in the stiffener flange. Three-point bend tests were performed to measure the skin/stiffener debonding strength and the recovered strength after healing. The first three tests performed indicated no healing following unloading and reloading. Micrographs showed that delaminations could migrate to the top of the interleaf layer due to the asymmetric loading, and hence, bypass most of the embedded capsules. For two subsequent tests, specimens were clamped in reverse bending before reloading. In one case, healing was observed as evidenced by healing agent that leaked to the specimen edge forming a visible "scar". The residual strength measured upon reloading was 96% of the original strength indicating healing had occurred. Hence, self-healing is possible in fiber reinforced composite material under controlled conditions, i.e., given enough time and contact with pressure on the crack surfaces. The micro-encapsulation technique may prove more robust when capsule sizes can be produced that are small enough to be embedded in the matrix resin without the need for using an interleaf layer. However, in either configuration, the amount of healing that can occur may be limited to the volume of healing agent available relative to the crack volume that must be filled.

O'Brien, T. Kevin↗
NASA NTRS2014

Characterization of Encapsulated Corrosion Inhibitors for Environmentally Friendly Smart Coatings

Research efforts are under way to replace current corrosion inhibitors with more environmentally friendly alternatives. However, problems with corrosion inhibition efficiency, coating compatibility and solubility have hindered the use of many of these materials as simple pigment additives.This paper will present technical details on how the Corrosion Technology Lab at NASAs Kennedy Space Center (KSC) has addressed these issues by encapsulating environmentally friendly inhibitors into organic and inorganic microparticles and microcapsules. The synthetic process for polymer particles was characterized and post-synthesis analysis was performed to determine the interactions between the inhibitors and the encapsulation material. The pH-controlled release of inhibitors from various particle formulations in aqueous base was monitored and compared to both electrochemical and salt immersion accelerated corrosion experiment. Furthermore, synergistic corrosion inhibition effects observed during the corrosion testing of several inhibitor combinations will be presented.

Environmentally Friendly↗
DOE OSTI2014

Separation of a target substance from a fluid or mixture using encapsulated sorbents

Method and apparatus for separating a target substance from a fluid or mixture. Capsules having a coating and stripping solvents encapsulated in the capsules are provided. The coating is permeable to the target substance. The capsules having a coating and stripping solvents encapsulated in the capsules are exposed to the fluid or mixture. The target substance migrates through the coating and is taken up by the stripping solvents. The target substance is separated from the fluid or mixture by driving off the target substance from the capsules.

42 ENGINEERING↗
DOE OSTI2014

Vacuum encapsulated hermetically sealed diamond amplified cathode capsule and method for making same

A vacuum encapsulated, hermetically sealed cathode capsule for generating an electron beam of secondary electrons, which generally includes a cathode element having a primary emission surface adapted to emit primary electrons, an annular insulating spacer, a diamond window element comprising a diamond material and having a secondary emission surface adapted to emit secondary electrons in response to primary electrons impinging on the diamond window element, a first cold-weld ring disposed between the cathode element and the annular insulating spacer and a second cold-weld ring disposed between the annular insulating spacer and the diamond window element. The cathode capsule is formed by a vacuum cold-weld process such that the first cold-weld ring forms a hermetical seal between the cathode element and the annular insulating spacer and the second cold-weld ring forms a hermetical seal between the annular spacer and the diamond window element whereby a vacuum encapsulated chamber is formed within the capsule.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2015

Low-melting elemental metal or fusible alloy encapsulated polymerization initiator for delayed initiation

An encapsulated composition for polymerization includes an initiator composition for initiating a polymerization reaction, and a capsule prepared from an elemental metal or fusible alloy having a melting temperature from about 20.degree. C. to about 200.degree. C. A fluid for polymerization includes the encapsulated composition and a monomer. When the capsule melts or breaks open, the initiator is released.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Vacuum encapsulated, high temperature diamond amplified cathode capsule and method for making same

A vacuum encapsulated, hermetically sealed cathode capsule for generating an electron beam of secondary electrons, which generally includes a cathode element having a primary emission surface adapted to emit primary electrons, an annular insulating spacer, a diamond window element comprising a diamond material and having a secondary emission surface adapted to emit secondary electrons in response to primary electrons impinging on the diamond window element, a first high-temperature solder weld disposed between the diamond window element and the annular insulating spacer and a second high-temperature solder weld disposed between the annular insulating spacer and the cathode element. The cathode capsule is formed by a high temperature weld process under vacuum such that the first solder weld forms a hermetical seal between the diamond window element and the annular insulating spacer and the second solder weld forms a hermetical seal between the annular spacer and the cathode element whereby a vacuum encapsulated chamber is formed within the capsule.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Metal oxide-encapsulated dye-sensitized photoanodes for dye-sensitized solar cells

Dye-sensitized semiconducting metal oxide films for photoanodes, photoanodes incorporating the films and DSCs incorporating the photoanodes are provided. Also provided are methods for making the dye sensitized semiconducting metal oxide films. The methods of making the films are based on the deposition of an encapsulating layer of a semiconducting metal oxide around the molecular anchoring groups of photosensitizing dye molecules adsorbed to a porous film of the semiconducting metal oxide. The encapsulating layer of semiconducting metal oxide is formed in such a way that it is not coated over the chromophores of the adsorbed dye molecules and, therefore, allows the dye molecules to remain electrochemically addressable.

14 SOLAR ENERGY↗
DOE OSTI2016

Encapsulated microsensors for reservoir interrogation

In one general embodiment, a system includes at least one microsensor configured to detect one or more conditions of a fluidic medium of a reservoir; and a receptacle, wherein the receptacle encapsulates the at least one microsensor. In another general embodiment, a method include injecting the encapsulated at least one microsensor as recited above into a fluidic medium of a reservoir; and detecting one or more conditions of the fluidic medium of the reservoir.

15 GEOTHERMAL ENERGY↗
DOE OSTI2016

Method of encapsulating a phase change material with a metal oxide

Storage systems based on latent heat storage have high-energy storage density, which reduces the footprint of the system and the cost. However, phase change materials (PCMs), such as NaNO.sub.3, NaCl, KNO.sub.3, have very low thermal conductivities. To enhave the storage of PCMs, macroencapsulation of PCMs was performed using a metal oxide, such as SiO.sub.2 or a graphene-SiO.sub.2, over polyimide-coated or nickel-embedded, polyimide-coated pellets The macro encapsulation provides a self-supporting structure, enhances the heat transfer rate, and provides a cost effective and reliable solution for thermal energy storage for use in solar thermal power plants. NaNO.sub.3 was selected for thermal storage in a temperature range of 300.degree. C. to 500.degree. C. The PCM was encapsulated in a metal oxide cell using self-assembly reactions, hydrolysis, and simultaneous chemical oxidation at various temperatures.

25 ENERGY STORAGE↗
DOE OSTI2017

Encapsulation of high temperature thermoelectric modules

A method of encapsulating a thermoelectric device and its associated thermoelectric elements in an inert atmosphere and a thermoelectric device fabricated by such method are described. These thermoelectric devices may be intended for use under conditions which would otherwise promote oxidation of the thermoelectric elements. The capsule is formed by securing a suitably-sized thin-walled strip of oxidation-resistant metal to the ceramic substrates which support the thermoelectric elements. The thin-walled metal strip is positioned to enclose the edges of the thermoelectric device and is secured to the substrates using gap-filling materials. The strip, substrates and gap-filling materials cooperatively encapsulate the thermoelectric elements and exclude oxygen and water vapor from atmospheric air so that the elements may be maintained in an inert, non-oxidizing environment.

47 OTHER INSTRUMENTATION↗
DOE OSTI2017

Low-melting elemental metal or fusible alloy encapsulated polymerization initiator for delayed initiation

An encapsulated composition for polymerization includes an initiator composition for initiating a polymerization reaction, and a capsule prepared from an elemental metal or fusible alloy having a melting temperature from about 20.degree. C. to about 200.degree. C. A fluid for polymerization includes the encapsulated composition and a monomer. When the capsule melts or breaks open, the initiator is released.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Separation of a target substance from a fluid or mixture using encapsulated sorbents

Method and apparatus for separating a target substance from a fluid or mixture. Capsules having a coating and stripping solvents encapsulated in the capsules are provided. The coating is permeable to the target substance. The capsules having a coating and stripping solvents encapsulated in the capsules are exposed to the fluid or mixture. The target substance migrates through the coating and is taken up by the stripping solvents. The target substance is separated from the fluid or mixture by driving off the target substance from the capsules.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Degradation in PV Encapsulant Transmittance: Results of the First PVQAT TG5 Study

Reduced optical transmittance of encapsulants resulting from ultraviolet (UV) degradation has frequently been identified as a cause of decreased PV module performance through the life of service in the field. The present module safety and qualification standards, however, apply short UV doses only capable of examining design robustness or 'infant mortality' failures. The latest versions of the safety and qualification apply ~40 - ~160 days cumulative dose of the AM1.5G total UV radiation. Essential information that might be used to screen encapsulation through product lifetime also remains unknown. For example, the relative efficacy of xenon-arc and UVA-340 fluorescent sources or the typical range of activation energy for degradation is not quantified. We have conducted an interlaboratory experiment to provide the understanding that will be used towards developing a higher fidelity, more rigorous UV weathering test. Five representative, known formulations of EVA were studied in addition to one TPU material. Replicate laminated silica/polymer/silica specimens were examined at 10 institutions using a variety of indoor chambers (including Xenon, UVA-340, and high pressure mercury light sources). Specimens were artificially weathered for 180 cumulative days at pre-designated accelerated test conditions. The solar-weighted transmittance, yellowness index, and the UV cut-off wavelength, determined from the measured hemispherical transmittance, are examined to provide understanding and guidance for the UV light source (lamp type) and temperature used in accelerated UV aging tests.

14 SOLAR ENERGY↗
DOE OSTI2020

Conformal graphene cage encapsulated battery electrode materials and methods of forming thereof

A conformal graphene-encapsulated battery electrode material is formed by: (1) coating a battery electrode material with a metal catalyst to form a metal catalyst-coated battery electrode material; (2) growing graphene on the metal catalyst-coated battery electrode material to form a graphene cage encapsulating the metal catalyst-coated battery electrode material; and (3) at least partially removing the metal catalyst to form a void inside the graphene cage.

Li, Yuzhang↗
DOE OSTI2021

Separation of a target substance from a fluid or mixture using encapsulated sorbents

Method and apparatus for separating a target substance from a fluid or mixture. Capsules having a coating and stripping solvents encapsulated in the capsules are provided. The coating is permeable to the target substance. The capsules having a coating and stripping solvents encapsulated in the capsules are exposed to the fluid or mixture. The target substance migrates through the coating and is taken up by the stripping solvents. The target substance is separated from the fluid or mixture by driving off the target substance from the capsules.

Aines, Roger D.↗
DOE OSTI2022

The encasulation effect on thermal performance of micro-encapsulated phase change materials during energy absorption

Understanding the performance of the thermal storage materials is required to successfully meet the needs of next generation concentrating solar power projects. This study focuses on the thermal characteristics of the micro-encapsulated phase change material (MEPCM) with metallic core under high temperature. A numerical model was developed and verified to study the transient heat absorption process of MEPCMs made of tin, aluminum and copper core. Convective heat transfer rate, total energy absorption and volumetric energy density were presented. The effect of encapsulation on theses variables was analyzed under various boundary and initial conditions. Its impact on characteristic time variables was discussed. The method presented can be adopted to analyzing both manufacturing and application processes for MEPCMs of various compositions, during which melting and solidification happen. Given certain operating conditions, the results from the model can be referenced to obtain optimal thermal performance of these materials.

Benner, Jingru↗
DOE OSTI2022

Encapsulation method for preparation of pellets with high attrition resistance

This disclosure provides a method to produce highly attrition resistant pellets by encapsulating reactive components in a vitrified clay outer layer. The reactive component mixture is present relative to the clay substrate in a weight ratio of part per 60-100 part to about 60 parts of the clay substrate. The reactive components are agglomerated first, and clay substrate is added to form the outer layer of the pellet. The pellets are calcined at temperatures above 1200 C to form a vitrified clay semi porous outer layer providing high strength to the pellet while facilitating the gas transfer for the reaction with the encapsulated reactive components. Pellets containing CuO—Fe 2 O 3 -alumina oxygen carrier for chemical looping combustion of fuel demonstrated high attrition resistance and high reactivity with methane.

Siriwardane, Ranjani↗