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The Ultimate Shaft-To-Hub Connection

Kinematically ground polygonal shapes have been used as drive connections for more than 45 years. What is now referred to as Polygon Systems was developed by Fortunawerke, Stuttgart, West Germany, who patented a grinding machine capable of producing matched polygonal shaft and bore diameters.

Posted in: White Papers, White Papers, Mechanical Components, Mechanics
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Laser Integration on Silicon Photonic Circuits Through Transfer Printing

The purpose of this project was to develop a transfer printing process for the massively parallel integration of III-V lasers on silicon photonic integrated circuits. Silicon has long offered promise as the ultimate platform for realizing compact photonic integrated circuits (PICs). That promise stems in part from the material's properties: the high refractive-index contrast of silicon allows strong confinement of the optical field, increasing light-matter interaction in a compact space—a particularly important attribute for realizing efficient modulators and high-speed detectors.

Posted in: Briefs, Aerospace, Photonics, Integrated circuits, Lasers, Fabrication, Materials properties, Semiconductors
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High Energy Computed Tomographic Inspection of Munitions

An advance computed tomography (CT) system was recently built for the U.S. Army Armament Research, Development and Engineering Center, Picatinny Arsenal, NJ, for the inspection of munitions. The system is a charged coupled device (CCD) camera based CT system designated with the name “experimental Imaging Media” (XIM). The design incorporated shielding for use up to 4MeV x-ray photons and integrated two separate cameras into one single field of view (FOV). Other major distinguishing characteristics include its processing functions to digitally piece the two cameras together, use of advanced artifact reduction principles, performing reconstruction simultaneously during acquisition, and its development in accurate beam hardening corrections through digital means.

Posted in: Briefs, Aerospace, Photonics, Charge coupled devices, Imaging, Defense industry, Inspections, Missiles
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Terahertz (THz) Radar: A Solution For Degraded Visibility Environments (DVE)

An accurate view of the physical world is frequently vital. For example, rotary wing aircraft pilots must have knowledge of the terrain in order to safely fly their aircraft. Therefore, systems capable of generating images of the environment of sufficient quality to facilitate the decision process are necessary. The product of such a system is illustrated in Figure 1.

Posted in: Briefs, Aerospace, Imaging, Cartography, Imaging, Radar, Terrain
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Imaging Detonations of Explosives

An effort has been made within the US Army Research Laboratory (ARL) to extract quantitative information on explosive performance from high-speed imaging of explosions. Explosive fireball surface temperatures are measured using imaging pyrometry (2-color 2-camera imaging pyrometer; full-color single-camera imaging pyrometer). Framing cameras are synchronized with pulsed laser illumination to measure fireball/shock expansion velocities, enabling calculation of peak air-shock pressures. Multicamera filtering at different wavelengths enables visualization of light emission by some reactant species participating in energy release during an explosion. Measurement of incident and reflected shock velocities is used to calculate shock energy on a target.

Posted in: Briefs, Aerospace, Imaging, Imaging, Thermodynamics, Defense industry, Missiles
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Development of Photoacoustic Sensing Platforms

In recent years, photoacoustic spectroscopy (PAS) has emerged as an attractive and powerful technique well suited for sensing applications. The development of high-power radiation sources and more sophisticated electronics, including sensitive microphones and digital lock-in amplifiers, have allowed for significant advances in PAS. Furthermore, photoacoustic (PA) detection of IR absorption spectra using modern tunable lasers offers several advantages, including simultaneous detection and discrimination of numerous molecules of interest. Successful applications of PAS in gases and condensed matter have made this a notable technique and it is now studied and employed by scientists and engineers in a variety of disciplines.

Posted in: Briefs, Aerospace, Photonics, Amplifiers, Electronic equipment, Lasers, Sensors and actuators, Spectroscopy, Acoustics
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Determining Detection and Classification Potential of Munitions Using Advanced EMI Sensors in the Underwater Environment

Hazardous ordnance items are present along coastlines and in rivers and lakes in waters shallow enough to cause concerns for human recreational and industrial activities. The presence of water makes it difficult to detect and remove these hazardous legacies induced from wars, military training and deliberate disposal. Various techniques have been proposed to detect and characterize Unexploded Ordnances (UXO) and discarded military munitions (DMM) in the underwater environment including acoustic waves, magnetometery, and electromagnetic induction (EMI).

Posted in: Briefs, Aerospace, Sensors, Sensors and actuators, Water, Defense industry, Conductivity, Hazardous materials, Marine vehicles and equipment, Missiles
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Concept Enables Solar UAV “Autonomous Soaring”

Naval Research Laboratory engineers want to improve the ability of unmanned platforms to support a 24/7 information, surveillance, and reconnaissance (ISR) mission. A new concept being tested consists of a photovoltaic array integrated into the center wing panel of the PV-SBXC aircraft as a drop-in replacement to the original wing. A power management and distribution system converts the power from the solar arrays into DC voltage that the electric motor can use for propulsion, or to recharge a smart battery.

Posted in: News, Aerospace, Aviation, Defense
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NASA Tests Prepare Space Launch System for Liftoff

NASA’s Space Launch System (SLS) may experience ground wind gusts of up to 70 mph as it sits on the launch pad before and during liftoff for future missions. Understanding how environmental factors affect the rocket will help NASA’s guidance, navigation, and control team to identify the safety distance between the rocket and the launch tower.

Posted in: News, Aerospace, Defense
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Lightweight Artificial Hair Sensors Could Enable “Fly by Feel”

The Air Force Research Laboratory was inspired by the hairs on bats and crickets in creation of artificial hair sensors that could assess the external environment and change maneuvers during flight. The need to understand ambient air data and its effects on aircraft performance, navigation, and more has become more critical as aircraft are now lighter and operate in diverse environments.

Posted in: News, Defense, Sensors
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