Test & Measurement

The Impact of Video Compression on Remote Cardiac Pulse Measurement Using Imaging Photoplethysmography

Remote measurement of physiological signals has a number of advantages over traditional contact methods. It allows the measurement of vital signals unobtrusively and concomitantly. In recent years, a number of approaches for imaging-based measurement of physiology using digital cameras have been proposed. Imaging photoplethysmography (iPPG) captures variations in light reflected from the body due to blood volume changes in microvascular tissue. It has been demonstrated that sub-pixel variations in color channel measurements from a digital single lens reflex (DSLR) camera, when aggregated, could be used to recover the blood volume pulse. Subsequently, it was shown that iPPG methods can allow accurate measurement of heart rate, heart rate variability, breathing rate, blood oxygenation and pulse transit time.

Posted in: Briefs, Aerospace, Test & Measurement
Read More >>

Subjective Mapping of Dust-Emission Sources by Using MODIS Imagery

Dust storms (5 to 100 km across) often originate from multiple dust-emission sources (1 to 10 km across). Remote-sensing-based dust-source identification is a challenge. A previous study developed a subjective approach for mapping dust sources by using enhanced MODIS satellite imagery; therefore, this study conducted mapping exercises to assess the reproducibility of this technique amongst multiple analysts and in different regions.

Posted in: Briefs, Aerospace, Test & Measurement
Read More >>

Custom Data Logger for Real-Time Remote Field Data Collections

The U.S. Army Corps of Engineers (USACE), CHL, FRF, had a need for a remote real-time data collection system to control instruments and log and communicate data from five observing stations in the Currituck Sound Estuary, NC1. These stations, referred to as the Currituck Sound Array (CSA), collect a suite of meteorological and oceano-graphic data including wind, air temperature, humidity, incoming solar radiation (above and below water), waves, currents, water level, salinity, and water temperature, as well as turbidity and many other water quality parameters. This array of instruments has a variety of control commands, sample routines, and output data formats. Additionally, the CSA was designed to act as a natural laboratory for estuarine research and as an instrument and model test bed. These capabilities required a reliable and flexible system that would allow easy modification of sampling schemes, the ability to log as many as 15 instruments with a single logger, and allow the incorporation of additional and novel instrumentation with minimal effort and expense.

Posted in: Briefs, Aerospace, Test & Measurement
Read More >>

Topology Control in Aerial Multi-Beam Directional Networks

In multi-beam directional networks, nodes are able to simultaneously transmit to all neighbors or receive from all neighbors. This spatial reuse allows for high throughputs, but in dense networks can cause significant interference. Topology control (i.e., selecting a subset of neighbors to communicate with) is vital to reduce the interference. Good topology control balances the number of links utilized to achieve fewer collisions while maintaining robust network connectivity.

Posted in: Briefs, Aerospace, Test & Measurement
Read More >>

NASA Tests Multi-Material 3D-Printed Rocket Engine Part

NASA engineers tested a 3D-printed rocket engine prototype part made of two different metal alloys via an advanced manufacturing process. The part was low-pressure, hot-fire-tested more than 30 times to demonstrate the functionality of the igniter.

Posted in: INSIDER, News, Defense, Test & Measurement
Read More >>

Green Aerospace Test Uses No Explosives

Sandia National Laboratories has successfully demonstrated a new, more environmentally friendly method to test a rocket part to ensure its avionics can withstand the shock from stage separation during flight. The Alternative Pyroshock Test uses a nitrogen-powered gas gun to shoot a 100-pound steel projectile into a steel resonant beam, which then transfers energy through a resonant cone attached to the part being tested. The resulting energy transfer mimics the conditions of stage separation in space.

Posted in: INSIDER, News, Defense, Test & Measurement
Read More >>

Researchers Test Minuteman III Intercontinental Ballistic Missile

As an unarmed Minuteman III intercontinental ballistic missile (ICBM) rocketed into the night sky, a team of Lawrence Livermore National Laboratory (LLNL) researchers listened intently to radio chatter and watched flight data stream in from a control room at the Ronald Reagan Ballistic Missile Defense Test Site. It was the first of two flight tests conducted recently to verify that the system could deliver a payload to target.

Posted in: News, Defense, Test & Measurement
Read More >>

Combustion Characteristics of Hydrocarbon Droplets Induced by Photoignition of Aluminum Nanoparticles

In the study of combustion characteristics of liquid rocket fuels, it is customary to either study the combustion of liquid fuel droplets or the combustion of fuel sprays. However, the two are closely related to each other, because in a typical rocket combustion chamber, the burning of droplets, droplet clusters, and fuel sprays occur simultaneously.

Posted in: Briefs, Aerospace, Defense, Propulsion, Test & Measurement, Spacecraft fuel, Aluminum, Combustion and combustion processes, Liquid propellant rocket engines
Read More >>

AMRDEC Technologies to Improve Air and Missile Defense

Engineers at the U.S. Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) are working on a trio of technologies to explore improving existing air and missile defense designs at lower costs and in less development time. Each of the technologies was developed out of a demand from the warfighter. Investment in current missile weapons is high so the Army prefers to improve what is in use instead of fielding new items. Also, soldiers have more trust in machinery they have used and experienced.

Posted in: News, Aerospace, Defense, Software, Test & Measurement
Read More >>

Drop of Mock Nuclear Weapon Is First of New Flight Tests

From a distance, the drop of a mock nuclear weapon — containing only non-nuclear components — was a mere puff of dust rising from a dry lake bed at Nevada’s Tonopah Test Range. However, it marked the start of a new series of test flights vital to the nation’s B61-12 weapon refurbishment program. Initial data showed the test was a success, said officials at Sandia National Laboratories, which runs Tonopah. For months, teams will be analyzing a wealth of data they collected from this first of a qualification test series planned over the next three years.

Posted in: News, Defense, Test & Measurement
Read More >>