United States of America as Represented by the Administrator of Nasa

National Institute of Aerospace Associates

Sang-Hyon Chu

Sang Hyouk Choi

Yeonjoon Park

Glen C King

Jae-Woo Kim

James R Elliott

Peter T Lillehei

Diane M Stoakley

Cheol Park

Jin Ho Kang

Catharine C Fay

John-Andrew S Hocker

A lightweight flexible BNNT mat or fabric provides improved thermal stability and shielding capabilities under a hypersonic thermal flux. The BNNT mat reduces the stagnation temperature and maintains a low regression rate. An in-situ passivation layer may be formed on the BNNT mat or fabric under high thermal flux. The passivation layer minimizes or prevents penetration of the atmosphere (air or gas) as well as heat and radiation through the thickness of the BNNT material, and it effectively diffuses heat throughout the mat or fabric laterally and radially to minimize localized excessive heat. A BNNT mat according to the present disclosure may also efficiently transfer heat from the BNNT material via radiation due to the high thermal emissivity (0.92) of the BNNT material.

In-situ passivation and insulation layer for a flexible thermal protection system (FTPS)

Metal and semiconductor nanoshells, particularly transition metal nanoshells, are fabricated using dendrimer molecules. Metallic colloids, metallic ions or semiconductors are attached to amine groups on the dendrimer surface in stabilized solution for the surface seeding method and the surface seedless method, respectively. Subsequently, the process is repeated with additional metallic ions or semiconductor, a stabilizer, and NaBHto increase the wall thickness of the metallic or semiconductor lining on the dendrimer surface. Metallic or semiconductor ions are automatically reduced on the metallic or semiconductor nanoparticles causing the formation of hollow metallic or semiconductor nanoparticles. The void size of the formed hollow nanoparticles depends on the dendrimer generation. The thickness of the metallic or semiconductor thin film around the dendrimer depends on the repetition times and the size of initial metallic or semiconductor seeds.

Fabrication of metallic hollow nanoparticles

A new fabrication method for nanovoids-imbedded bismuth telluride (Bi&#x2014;Te) material with low dimensional (quantum-dots, quantum-wires, or quantum-wells) structure was conceived during the development of advanced thermoelectric (TE) materials. Bismuth telluride is currently the best-known candidate material for solid-state TE cooling devices because it possesses the highest TE figure of merit at room temperature. The innovative process described here allows nanometer-scale voids to be incorporated in Bi&#x2014;Te material. The final nanovoid structure such as void size, size distribution, void location, etc. can be also controlled under various process conditions.

Fabrication of nanovoid-imbedded bismuth telluride with low dimensional system

Metal nanoshells are fabricated by admixing an aqueous solution of metal ions with an aqueous solution of apoferritin protein molecules, followed by admixing an aqueous solution containing an excess of an oxidizing agent for the metal ions. The apoferritin molecules serve as bio-templates for the formation of metal nanoshells, which form on and are bonded to the inside walls of the hollow cores of the individual apoferritin molecules. Control of the number of metal atoms which enter the hollow core of each individual apoferritin molecule provides a hollow metal nonparticle, or nanoshell, instead of a solid spherical metal nanoparticle.

Fabrication of metal nanoshells

A dynamic optical grating device and associated method for modulating light is provided that is capable of controlling the spectral properties and propagation of light without moving mechanical components by the use of a dynamic electric and/or magnetic field. By changing the electric field and/or magnetic field, the index of refraction, the extinction coefficient, the transmittivity, and the reflectivity of the optical grating device may be controlled in order to control the spectral properties of the light reflected or transmitted by the device.

Dynamic optical grating device and associated method for modulating light

A novel method to prepare an advanced thermoelectric material has hierarchical structures embedded with nanometer-sized voids which are key to enhancement of the thermoelectric performance. Solution-based thin film deposition technique enables preparation of stable film of thermoelectric material and void generator (voigen). A subsequent thermal process creates hierarchical nanovoid structure inside the thermoelectric material. Potential application areas of this advanced thermoelectric material with nanovoid structure are commercial applications (electronics cooling), medical and scientific applications (biological analysis device, medical imaging systems), telecommunications, and defense and military applications (night vision equipments).

Fabrication of advanced thermoelectric materials by hierarchical nanovoid generation

A new High Altitude Airship (HAA) capable of various extended applications and mission scenarios utilizing inventive onboard energy harvesting and power distribution systems. The power technology comprises an advanced thermoelectric (ATE) thermal energy conversion system. The high efficiency of multiple stages of ATE materials in a tandem mode, each suited for best performance within a particular temperature range, permits the ATE system to generate a high quantity of harvested energy for the extended mission scenarios. When the figure of merit 5 is considered, the cascaded efficiency of the three-stage ATE system approaches an efficiency greater than 60 percent.

High altitude airship configuration and power technology and method for operation of same

A thin-film electrode for a bio-nanobattery is produced by consecutively depositing arrays of a ferritin protein on a substrate, employing a spin self-assembly procedure. By this procedure, a first ferritin layer is first formed on the substrate, followed by building a second, oppositely-charged ferritin layer on the top of the first ferritin layer to form a bilayer structure. Oppositely-charged ferritin layers are subsequently deposited on top of each other until a desired number of bilayer structures is produced. An ordered, uniform, stable and robust, thin-film electrode material of enhanced packing density is presented, which provides optimal charge density for the bio-nanobattery.

Growing community of inventors

Newport News, VA, United States of America

Sang-Hyon Chu