Tech Briefs

Cryogenic Slosh Apparatus

John F. Kennedy Space Center, Florida Commercially available components are integrated into an assembly that can be used to measure the slosh dynamics of cryogenic liquids. The apparatus consists of a linear motion table that is properly instrumented to record highfidelity position, force, and acceleration measurements of all linear and rotation responses of the cryogenic liquid.

Posted in: Briefs, Measuring Instruments

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Negative-Ion Time Projection Chamber Polarimeter for Measuring Polarization of Bright Transient Astrophysical Sources

Goddard Space Flight Center, Greenbelt, Maryland A negative ion time projection chamber (NI-TPC) was developed that is suitable for measuring the polarization of bright transient events. The polarization of the astrophysical source is determined by imaging photoelectron tracks created by incident x-rays interacting in a gas. The tracks drift through the gas under a uniform electric field to the readout electronics. The initial photoelectron direction is correlated with the polarization of the incident x-ray, and therefore by imaging many tracks, one can determine the polarization magnitude and direction of the incident x-rays.

Posted in: Briefs, TSP, Measuring Instruments

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A Large-Eddy Simulation Model of the Atmospheric Boundary Layer

The model includes the interaction of various physical processes, including turbulence, clouds, precipitation, and radiation. NASA’s Jet Propulsion Laboratory, Pasadena, California The atmospheric boundary layer is the lowermost layer of the atmosphere and is host to a plethora of physical processes that significantly affect weather, climate, and air quality. In many applications, detailed information about the boundary layer is required at high temporal and spatial resolution. The main purpose of the current model is to provide accurate and finely resolved inspace and time predictions of the atmospheric boundary layer. High-resolution predictions of the boundary layer are typically pertinent in the development and evaluation of weather and climate models, in fundamental studies of atmospheric dynamics including clouds and precipitation, the dispersion of pollutants, and the development of remote sensing instruments.

Posted in: Briefs, Electronics & Computers, Simulation Software

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Hydrogen Peroxide for Microbial Growth Control in Space Potable Water Systems

This on-demand generator can provide the needed hydrogen peroxide levels for microbial growth control in potable water holding tanks and waterlines. Marshall Space Flight Center, Alabama NASA uses a biocide to prevent contamination of astronaut drinking water with harmful microorganisms. Concerns have arisen over existing biocides — that they’re inadequately effective, and may have toxic side effects when consumed. New microbial control methods are a priority. This need is addressed by using an electrochemical reactor for on-demand generation of hydrogen peroxide (H2O2) solutions. The device uses onboard resources only. The method eliminates the need for resupply items (reducing launch costs), and reduces toxicity risk.

Posted in: Briefs

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Nonlinear Swept Frequency Technique for CO2 Measurements Using a CW Laser System

The measurements would be used to significantly reduce the uncertainties in global estimates of CO2, improve climate models, and close the carbon budget for improved forecasting and policy decisions. Langley Research Center, Hampton, Virginia The U.S. National Research Council recently identified the need for a near-term space mission of Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS). The primary objective of the ASCENDS mission is to make CO2 column measurements across the troposphere during the day and night over all latitudes and all seasons, and in the presence of scattered clouds. These measurements would be used to significantly reduce the uncertainties in global estimates of CO2 sources and sinks, provide an increased understanding of the connection between climate and CO2 exchange, improve climate models, and close the carbon budget for improved forecasting and policy decisions.

Posted in: Briefs, TSP, Greenhouse Gases, Lasers & Laser Systems

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Method of Water Regeneration From Waste and Cascade Distillation

Lyndon B. Johnson Space Center, Houston, Texas Effective recovery of potable water from various streams and sources of wastewater, seawater, or contaminated water is a significant task for securing existence of human beings in space, terrestrial, and marine environments. Efficient purification of the wastewater is also a very important task for protection of the global environment. The existing and known methods of recovery of clean water from the wastewater are technically complicated, have low energy efficiency, consume processing material, and are bulky, heavy, and not cost effective.

Posted in: Briefs, Recycling Technologies

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Reducing Power-On/Off Glitches in Precision DACs

Voltage glitches are common in a signal chain path, especially when the system is being powered up or down. Depending on the peak amplitude and glitch duration, the end result in the system output can be catastrophic. One example is an industrial motor control system where a digital-to-analog converter (DAC) drives the motor drivers to control motor spin. If the glitch amplitude is higher than the motor driver’s sensitivity threshold, the motor could be spinning without control in any direction when the system is powered up/down.

Posted in: Briefs, Power Management, Motors & Drives

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