Materials & Coatings

Plasma Extraction of Oxygen from the Martian Atmosphere

Microwave plasmas use systems that are smaller, lighter, and less complex than traditional reactors. Marshall Space Flight Center, Alabama Extraction of oxygen from the abundant carbon dioxide present on Mars (96% atmospheric composition) is an important objective in preparation for missions to the planet. Oxygen is not only a fundamental reactant with high-specific-energy chemical fuels such as hydrogen and methane, but, along with water, it is arguably one of the most critical resources for life support. Using microwave plasma techniques to decompose CO2 into CO and O2, coupled with a technology to separate O2 as it is produced, a robotic processor located on the Martian surface would allow oxygen to be stockpiled for later use. Using innovative standing-wave microwave plasma reactor designs, ubiquitous 2.45-GHz microwave technology was employed to demonstrate 86% single-pass carbon dioxide decomposition.

Posted in: Briefs, Materials

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Application of Carbon Nanotube Hold-Off Voltage for Determining Gas Composition

Ames Research Center, Moffett Field, California In this innovation, a method and associated system have been created to vary a voltage applied to an exposed end of a carbon nanotube for a selected time interval to promote gas discharge, and to estimate a gas component involved in the discharge. Each component of a gas has a first, lower threshold discharge (voltage value, V∞) at which discharge can occur after a long time delay (t(V∞:ho)≈∞), where “ho” refers to a discharge voltage holdoff value. Application of a voltage V above this lower limit V∞ will cause the gas component to undergo a discharge after a discharge holdoff time t(V:ho) that decreases as V increases above V∞.

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Design to Manufacturing: Complete Support for High-Precision Components

The medical device, aerospace, and automotive industries are fast-moving, complex, and highly competitive. They demand suppliers who are willing and able to meet even the most rigorous production requirements, quality standards, and timetables.

Posted in: White Papers, Manufacturing & Prototyping, Coatings & Adhesives, Materials

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Regenerable Trace-Contaminant Sorbent for the Primary Life Support System (PLSS)

This technology has applications in air-revitalization systems on spacecraft, submarines, automobiles, and commercial aircraft. Lyndon B. Johnson Space Center, Houston, Texas The NASA objective of expanding the human experience into the far reaches of space requires the development of regenerable life support systems. This work addresses the development of a regenerable air-revitalization system for trace-contaminant (TC) removal for the spacesuit used in extravehicular activities (EVAs). Currently, a bed of granular activated carbon is used for TC control. The carbon is impregnated with phosphoric acid to enhance ammonia sorption, but this also makes regeneration difficult, if not impossible. Temperatures as high as 200 °C have been shown to be required for only partial desorption of ammonia on time scales of 18,140 hours. Neither these elevated temperatures nor the long time needed for sorbent regeneration are acceptable. Thus, the activated carbon has been treated as an expendable resource, and the sorbent bed has been oversized in order to last throughout the entire mission.

Posted in: Briefs, TSP, Materials

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Lithium Fluoride as a Polysulfide Shuttle Inhibitor for Lithium Sulfur Chemistry

This invention imparts properties such as reinforcement, enhanced tensile strength, and/or electrical and thermal conductivity to composites. Lyndon B. Johnson Space Center, Houston, Texas In a lithium sulfur cell, the reduction of sulfur to lithium sulfide is a critical series of reactions that provides a large theoretical capacity of 1,672 mAh/g sulfur. One of many challenges in this system is the solubility of generated lithium polysulfides during the charge/discharge process. These polysulfides derived from the reduction of elemental sulfur are soluble in organic electrolytes, and can be reduced at the anode, causing an undesired reaction. Polysulfide species can also accumulate at the surface of the cathode and be further reduced to lower-order polysulfides such as Li2S2 or Li2S. The insulating nature of these lower-order polysulfides blocks the electron pathway on the carbon cathode.

Posted in: Briefs, TSP, Materials

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Fibers of Aligned Single-Wall Carbon Nanotubes and Process for Making the Same

This invention imparts properties such as reinforcement, enhanced tensile strength, and/or electrical and thermal conductivity to composites. Single-wall carbon nanotubes (SWNTs) are fullerenes of closed-cage carbon molecules typically arranged in hexagons and pentagons. Commonly known as “buckytubes,” these cylindrical carbon structures have extraordinary properties, including high electrical and thermal conductivity, as well as high strength and stiffness. With intrinsic strength estimated to be on the order of 100 times that of steel, SWNTs are a possible strengthening reinforcement in composite materials. The intrinsic electronic properties of SWNTs also make them electrical conductors and useful in applications involving field mission devices such as flat-panel displays, and in polymers used for radio frequency interference and electromagnetic shielding that require electrical conductance properties.

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Enhancing MRI Contrast by Geometrical Confinement of Small Imaging Agents Within Nanoporous Particles

Lyndon B. Johnson Space Center, Houston, Texas Magnetic resonance imaging (MRI) has evolved into one of the most powerful, non-invasive diagnostic imaging techniques in medicine and biomedical research. The superior resolution and in-depth anatomical details provided by MRI are essential for early diagnosis of many diseases. Chemical contrast agents (CAs) have been widely used for improving the sensitivity and diagnostic confidence in MRI.

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