Special Coverage

Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research
Small Robot Has Outstanding Vertical Agility
Smart Optical Material Characterization System and Method
Lightweight, Flexible Thermal Protection System for Fire Protection

Fabrication of Polyimide-Matrix/Carbon and Boron-Fiber Tape

Production costs can be reduced and compression strengths increased. The term “HYCARB” denotes a hybrid composite of polyimide matrices reinforced with carbon and boron fibers. HYCARB and an improved process for fabricating dry HYCARB tapes have been invented in a continuing effort to develop lightweight, strong composite materials for aerospace vehicles. Like other composite tapes in this line of development, HYCARB tapes are intended to be used to build up laminated structures having possibly complex shapes by means of automated tow placement (ATP) — a process in which a computer controlled multiaxis machine lays down prepreg tape or tows. The special significance of the present process for making dry HYCARB for ATP is that it contributes to the reduction of the overall cost of manufacturing boron-reinforced composite-material structures while making it possible to realize increased compression strengths.

Posted in: Briefs, Materials, Fabrication, Composite materials, Fibers, Polymers, Spacecraft


Composite Elastic Skins for Shape-Changing Structures

Anisotropic stiffness properties can be tailored for specific applications. Composite elastic skins having tailorable mechanical properties have been invented for covering shape-changing (“morphable”) structures. These skins are intended especially for use on advanced aircraft that change shapes in order to assume different aerodynamic properties.

Posted in: Briefs, TSP, Materials, Composite materials, Elastomers, Aircraft


Glass/Ceramic Composites for Sealing Solid Oxide Fuel Cells

Ceramic fillers in a glass contribute to strength and fracture toughness. A family of glass/ceramic composite materials has been investigated for use as sealants in planar solid oxide fuel cells. These materials are modified versions of a barium calcium aluminosilicate glass developed previously for the same purpose. The composition of the glass in mole percentages is 35BaO + 15CaO + 5Al2O3 + 10B2O3 + 35SiO2. The glass seal was found to be susceptible to cracking during thermal cycling of the fuel cells.

Posted in: Briefs, TSP, Materials, Fuel cells, Ceramics, Composite materials, Glass


Carbon-Nanotube-Carpet Heat-Transfer Pads

The compliance and high longitudinal thermal conductivity of carbon nanotubes are exploited. Microscopic thermal-contact pads that include carpetlike arrays of carbon nanotubes have been invented for dissipating heat generated in integrated circuits and similarly sized single electronic components. The need for these or other innovative thermal-contact pads arises because the requisite high thermal conductances cannot be realized by scaling conventional macroscopic thermal-contact pads down to microscopic sizes. Overcoming limitations of conventional thermal-contact materials and components, the carbon-nanotube thermal-contact pads offer the high thermal conductivities needed to accommodate the high local thermal power densities of modern electronic circuits, without need for large clamping pressures, extreme smoothness of surfaces in contact, or gap-filling materials (e.g., thermally conductive greases) to ensure adequate thermal contact. Moreover, unlike some conventional thermal-contact components, these pads are reusable.

Posted in: Briefs, TSP, Materials


Wholly Aromatic Ether-Imides as n-Type Semiconductors

Some of the compounds exhibit promising electron-transport properties. Some wholly aromatic ether-imides consisting of rod-shaped, relatively-low-mass molecules that can form liquid crystals have been investigated for potential utility as electron-donor-type (n-type) organic semiconductors. It is envisioned that after further research to improve understanding of their physical and chemical properties, compounds of this type would be used to make thin-film semiconductor devices (e.g., photovoltaic cells and field-effect transistors) on flexible electronic-circuit substrates.

Posted in: Briefs, TSP, Materials


Making Activated Carbon by Wet Pressurized Pyrolysis

Thermomechanical instabilities and associated frequency instabilities are reduced. A wet pressurized pyrolysis (wet carbonization) process has been invented as a means of producing activated carbon from a wide variety of inedible biomass consisting principally of plant wastes. The principal intended use of this activated carbon is room-temperature adsorption of pollutant gases from cooled incinerator exhaust streams.

Posted in: Briefs, Materials, Forming, Biomaterials


Composite Solid Electrolyte Containing Li+- Conducting Fibers

Li+-ion conductivities are greater than those achieved before. Improved composite solid polymer electrolytes (CSPEs) are being developed for use in lithium-ion power cells. The matrix components of these composites, like those of some prior CSPEs, are highmolecular- weight dielectric polymers [generally based on polyethylene oxide (PEO)]. The filler components of these composites are continuous, highly-Li+- conductive, inorganic fibers.

Posted in: Briefs, TSP, Materials, Lithium-ion batteries, Composite materials, Electrolytes, Polymers


The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.