News

Technique Generates Electricity from Mechanical Vibrations

Research scientists at VTT Technical Research Centre of Finland have demonstrated a new technique for generating electrical energy. The method can be used in harvesting energy from mechanical vibrations of the environment and converting it into electricity. Energy harvesters are needed in wireless self-powered sensors and medical implants, where they could ultimately replace batteries. The technology could be introduced on an industrial scale within three to six years.

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Researchers Measure Stress in 3D-Printed Metal Parts

Lawrence Livermore National Laboratory researchers have developed an efficient method to measure residual stress in metal parts produced by powder-bed fusion additive manufacturing (AM).The 3D-printing process produces metal parts layer by layer using a high-energy laser beam to fuse metal powder particles. When each layer is complete, the build platform moves downward by the thickness of one layer, and a new powder layer is spread on the previous layer.While the method produces quality parts and components, residual stress is a major problem during the fabrication process. Large temperature changes near the last melt spot, and the repetition of this process, result in localized expansion and contraction.An LLNL research team, led by engineer Amanda Wu, has developed an accurate residual stress measurement method that combines traditional stress-relieving methods (destructive analysis) with modern technology: digital image correlation (DIC). The process provides fast and accurate measurements of surface-level residual stresses in AM parts.The team used DIC to produce a set of quantified residual stress data for AM, exploring laser parameters. DIC is a cost-effective, image analysis method in which a dual camera setup is used to photograph an AM part once before it’s removed from the build plate for analysis and once after. The part is imaged, removed, and then re-imaged to measure the external residual stress.SourceAlso: Learn about Design and Analysis of Metal-to-Composite Nozzle Extension Joints.

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NASA Computer Model Reveals Carbon Dioxide Levels

An ultra-high-resolution NASA computer model has given scientists a stunning new look at how carbon dioxide in the atmosphere travels around the globe.Plumes of carbon dioxide in the simulation swirl and shift as winds disperse the greenhouse gas away from its sources. The simulation also illustrates differences in carbon dioxide levels in the northern and southern hemispheres, and distinct swings in global carbon dioxide concentrations as the growth cycle of plants and trees changes with the seasons.Scientists have made ground-based measurements of carbon dioxide for decades and in July NASA launched the Orbiting Carbon Observatory-2 (OCO-2) satellite to make global, space-based carbon observations. But the simulation — the product of a new computer model that is among the highest-resolution ever created — is the first to show in such fine detail how carbon dioxide actually moves through the atmosphere.In addition to providing a striking visual description of the movements of an invisible gas like carbon dioxide, as it is blown by the winds, this kind of high-resolution simulation will help scientists better project future climate. Engineers can also use this model to test new satellite instrument concepts to gauge their usefulness. The model allows engineers to build and operate a “virtual” instrument inside a computer.SourceAlso: Learn about the NASA Data Acquisition System (NDAS).

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3D Audio Research Helps Make Cockpit Safer

Imagine yourself in a cockpit, flying a mission, listening to a multitude of critical voices delivering vital messages, all at the same time and from the same direction. Now imagine the same environment, except that the voices are now distinct and separate. The Air Force Research Laboratory (AFRL) has developed 3D sound technology that creates a sound environment that mimics the way the human body receives aural cues, much like 3D movies create the perception that the viewer is part of the movie.

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NASA Tests Revolutionary Shape-Changing Aircraft Flap

NASA's green aviation project is one step closer to developing technology that could make future airliners quieter and more fuel‑efficient with the successful flight test of a wing surface that can change shape in flight. Researchers replaced an airplane’s conventional aluminum flaps with advanced, shape‑changing assemblies that form seamless bendable and twistable surfaces. Flight testing will determine whether flexible trailing‑edge wing flaps are a viable approach to improve aerodynamic efficiency and reduce noise generated during takeoffs and landings.

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Supersonic Laser-Propelled Rockets Could Help Aircraft Exceed Mach 10

A new method for improving the thrust generated by laser-propulsion systems may bring them one step closer to practical use. The method, developed by physicists Yuri Rezunkov of the Institute of Optoelectronic Instrument Engineering, Russia, and Alexander Schmidt of the Ioffe Physical Technical Institute in Saint Petersburg, Russia, integrates a laser‑ablation propulsion system with the gas‑blasting nozzles of a spacecraft. Combining the two systems can increase the speed of the gas flow out of the system to supersonic speeds, while reducing the amount of burned fuel.

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Will comet missions yield valuable information about the origin of the solar system?

This week's Question: The Philae spacecraft successfully landed on a moving comet last week. Scientists hope to be able to study the material beneath the surface of the solar body, which is traveling through space at 41,000 mph, hundreds of millions of miles away from Earth. Probing the comet’s dust could help researchers determine the origins of life on Earth, and whether comets provided the water that exists in oceans today. Since the material has remained almost unchanged for 4.5 billion years, it is considered by some researchers to be a "cosmic time capsule" that may contain the building blocks of life. What do you think? Will comet missions yield valuable information about the origin of the solar system?

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