Special Coverage

Lightweight Internal Device to Measure Tension in Hollow- Braided Cordage
System, Apparatus, and Method for Pedal Control
Dust Tolerant Connectors
Foldable and Deployable Power Collection System
Iodine-Compatible Hall Effect Thruster
Development of a Novel Electrospinning System with Automated Positioning and Control Software
Home

Predicting Properties of Unidirectional-Nanofiber Composites

A theory for predicting mechanical, thermal, electrical, and other properties of unidirectional- nanofiber/matrix composite materials is based on the prior theory of micromechanics of composite materials. In the development of the present theory, the prior theory of micromechanics was extended, through progressive substructuring, to the level of detail of a nanoscale slice of a nanofiber. All the governing equations were then formulated at this level.

Posted in: Briefs, Materials

Read More >>

Deployable Crew Quarters

The deployable crew quarters (DCQ) have been designed for the International Space Station (ISS). Each DCQ would be a relatively inexpensive, deployable box-like structure that is designed to fit in a rack bay. It is to be occupied by one crewmember to provide privacy and sleeping functions for the crew. A DCQ comprises mostly hard panels, made of a lightweight honeycomb or matrix/fiber material, attached to each other by cloth hinges. Both faces of each panel are covered with a layer of Nomex cloth and noise-suppression material to provide noise isolation from ISS.

Posted in: Briefs, TSP, Mechanical Components

Read More >>

Nonventing, Regenerable, Lightweight Heat Absorber

A lightweight, regenerable heat absorber (RHA), developed for rejecting metabolic heat from a space suit, may also be useful on Earth for short-term cooling of heavy protective garments. Unlike prior space-suit-cooling systems, a system that includes this RHA does not vent water. The closed system contains water reservoirs, tubes through which water is circulated to absorb heat, an evaporator, and an absorber/radiator. The radiator includes a solution of LiCl contained in a porous material in titanium tubes.

Posted in: Briefs, TSP, Mechanical Components

Read More >>

“Bootstrap” Configuration for Multistage Pulse-Tube Coolers

A “bootstrap” configuration has been proposed for multistage pulse-tube coolers that, for instance, provide final-stage cooling to temperatures as low as 20 K. The bootstrap configuration supplants the conventional configuration, in which customarily the warm heat exchangers of all stages reject heat at ambient temperature. In the bootstrap configuration, the warm heat exchanger, the inertance tube, and the reservoir of each stage would be thermally anchored to the cold heat exchanger of the next warmer stage. The boot-strapped configuration is superior to the conventional setup, in some cases increasing the 20 K cooler’s coefficient of performance two-fold over that of an otherwise equivalent conventional layout. The increased efficiency could translate into less power consumption, less cooler mass, and/or lower cost for a given amount of cooling.

Posted in: Briefs, TSP, Mechanical Components

Read More >>

Miniature High-Force, Long-Stroke SMA Linear Actuators

Stroke forces, stroke lengths, cycle speeds, and structural strengths are increased. Improved long-stroke shape-memory-alloy (SMA) linear actuators are being developed to exert significantly higher forces and operate at higher activation temperatures than do prior SMA actuators. In these actuators, long linear strokes are achieved through the principle of displacement multiplication, according to which there are multiple stages, each intermediate stage being connected by straight SMA wire segments to the next stage so that relative motions of stages are additive toward the final stage, which is the output stage.

Posted in: Briefs, TSP, Mechanical Components

Read More >>

Reducing Liquid Loss During Ullage Venting in Microgravity

A centripetal- force- based liquid/gas separator has been proposed as a means of reducing the loss of liquid during venting of the ullage of a tank in microgravity as a new supply of liquid is pumped into the tank. Centripetal-force-based liquid/gas separators are used on Earth, where mechanical drives (e.g., pumps and spinners) are used to impart flow speeds sufficient to generate centripetal forces large enough to effect separation of liquids from gases.

Posted in: Briefs, Mechanical Components

Read More >>

Accuracy versus Resolution in Analyzing System Errors

Distinguishing between accuracy and resolution can be misinterpreted in determining system needs. To ensure a system’s accuracy meets required needs, system error budgets must be an integral part of system design. Considerations should include necessary levels of accuracy for system elements, as well as such issues as compatibility between software algorithm calculations and measurement accuracy – meaning resolution must also be taken into account.

Posted in: Briefs, Physical Sciences

Read More >>

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