Special Coverage

Clamshell Sampler
Shape Memory Alloy Rock Splitter
Deployable Extra-Vehicular Activity Platform (DEVAP) for Planetary Surfaces
2016 Create The Future Design Contest Open For Entries
The Future of Exploration Starts With 3D Printing
Home

DMAC and NMP as Electrolyte Additives for Li-Ion Cells

High-temperature resilience is increased. Dimethyl acetamide (DMAC) and N-methyl pyrrolidinone (NMP) have been found to be useful as high- temperature- resilience-enhancing additives to a baseline electrolyte used in rechargeable lithium-ion electrochemical cells. The baseline electrolyte, which was previously formulated to improve low-temperature performance, comprises LiPF6 dissolved at a concentration of 1.0 M in a mixture comprising equal volume proportions of ethylene carbonate, diethyl carbonate, and dimethyl carbonate. This and other electrolytes comprising lithium salts dissolved in mixtures of esters (including alkyl carbonates) have been studied in continuing research directed toward extending the lower limits of operating temperatures and, more recently, enhancing the high-temperature resilience of such cells. This research at earlier stages, and the underlying physical and chemical principles, were reported in numerous previous NASA Tech Briefs articles.

Posted in: Briefs, TSP

Read More >>

Mass Spectrometer Containing Multiple Fixed Collectors

Two mass analyzers in a compact package detect five ion species simultaneously. A miniature mass spectrometer that incorporates features not typically found in prior mass spectrometers is undergoing development. This mass spectrometer is designed to simultaneously measure the relative concentrations of five gases (H2, He, N2, O2, and Ar) in air, over the relative-concentration range from 10–6 to 1, during a sampling time as short as 1 second. It is intended to serve as a prototype of a product line of easy-to-use, portable, light-weight, high-speed, relatively inexpensive instruments for measuring concentrations of multiple chemical species in such diverse applications as detecting explosive or toxic chemicals in air, monitoring and controlling industrial processes, measuring concentrations of deliberately introduced isotopes in medical and biological investigations, and general environmental monitoring.

Posted in: Briefs

Read More >>

Waveguide Harmonic Generator for the SIM

A second-harmonic generator (SHG) serves as the source of the visible laser beam in an onboard calibration scheme for NASA’s planned Space Interferometry Mission (SIM), which requires an infrared laser beam and a visible laser beam coherent with the infrared laser beam. The SHG includes quasi-phase-matched waveguides made of MgO-doped, periodically poled lithium niobate, pigtailed with polarization-maintaining optical fibers. Frequency doubling by use of such waveguides affords the required combination of coherence and sufficient conversion efficiency for the intended application. The spatial period of the poling is designed to obtain quasi-phase-matching at a nominal middle excitation wavelength of 1,319.28 nm.

Posted in: Briefs

Read More >>

America’s Premier Nano Engineering Event

The 2008 NASA Tech Briefs National Nano Engineering Conference (NNEC), be held November 12-13 at the Boston Colonnade Hotel, is for design engineers who want to know what’s real, what’s close to market, and what might be coming in the world of nanotechnology. The NNEC will help you keep pace with the engineering and technology innovations behind the latest nanotech breakthroughs. Included will be technical presentations and exhibits from companies leading the nanotech industry in application areas such as biomedical, electronics, advanced materials, energy and the environment, and business. Read about some of those advanced technologies below. You’ll also find networking opportunities, and the expert insight you’ll need to stay ahead of the small-tech curve.

Posted in: Articles

Read More >>

Whispering Gallery Mode Resonator With Orthogonally Reconfigurable Filter Function

An optical resonator has been developed with reconfigurable filter function that has resonant lines that can be shifted precisely and independently from each other, creating any desirable combination of resonant lines. This is achieved by changing the axial distribution of the effective refractive index of the resonator, which shifts the resonant frequency of particular optical modes, leaving all the rest unchanged. A reconfigurable optical filter is part of the remote chemical detector proposed for the Mars mission (Planetary Instrument Definition and Development Program — PIDDP), but it is also useful for photonic communications devices.

Posted in: Briefs

Read More >>

Bimaterial Thermal Compensators for WGM Resonators

Net thermal drifts of spectra would be cancelled to first order. Bimaterial thermal compensators have been proposed as inexpensive means of preventing (to first order) or reducing temperature-related changes in the resonance frequencies of whispering-gallery- mode (WGM) optical resonators. A bimaterial compensator would apply, to a WGM resonator, a pressure that would slightly change the shape of the resonator and thereby change its resonance frequencies. Through suitable choice of the compensator dimensions and materials, it should be possible to make the temperature dependence of the pressureinduced frequency shift equal in magnitude and opposite in sign to the temperature dependence of the frequency shift of the uncompensated resonator so that, to first order, a change in temperature would cause zero net change in frequency.

Posted in: Briefs

Read More >>

Powered by Lithium-Ion Batteries, NASA Spacecraft Explore Mars and the Moon

Lithium-ion batteries Yardney Technical Products Pawcatuck, CT 860-599-1100 www.yardney.com NASA’s Phoenix Mars Lander landed safely near the planet’s north polar icecap in May. Phoenix relies on advanced lithiumion batteries from Yardney Technical Products to dig and look for water, seeking a habitable environment. The Phoenix batteries provide power at night when there is no sunlight for the solar panels to convert to electricity. They can also be used any time when a task requires more power than the primary power source can deliver.

Posted in: Application Briefs

Read More >>

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