Physical Sciences

Miniature Snapshot Multispectral Imager

Multispectral imagers use an optical device that can separate the colors to obtain the spectral content in the scene. Such an optical device could be a grating or prism, a filter wheel, a diffractive optic lens, a Fabry-Perot (F-P) etalon, or a tunable filter. All of these optical devices are used with a focal plane array (FPA) and suitable optics for a given spectral region. All such imagers collect images in a time-sequential manner. Recently, some multispectral imagers have been developed that collect images of the scene at all the spectral bands simultaneously.

Posted in: Briefs, Physical Sciences, Imaging, Microelectricmechanical device, Optics

Distributed, Collaborative Human- Robotic Networks for Search, Identify, and Track

A human-robotic system is under development that can map an unknown environment, as well as discover, track, and neutralize several static and dynamic objects of interest. In addition, the robots can coordinate their individual tasks with one another without overly burdening a human operator. The testbed utilizes the Segway RMP platform, with lidar, vision, inertial, and GPS sensors. The software draws from autonomous systems research, specifically in the areas of pose estimation, target detection and tracking, motion and behavioral planning, and human robot interaction.

Posted in: Briefs, Physical Sciences, Architecture, Computer software / hardware, Surveillance, Human machine interface (HMI), Product development, Robotics

Multifunctional Vehicle Structural Health Monitoring with Piezoelectric Wafer Active Sensors

A novel structural health monitoring (SHM) concept of embedded nondestructive evaluation with piezoelectric wafer active sensors (PWAS) has been developed. PWAS can be structurally embedded as both individual probes and phased arrays. They can be placed inside closed cavities during fabrication/ overhaul (such as wing structures), and then be left in place for the life of the structure. The embedded nondestructive evaluation (NDE) concept opens new horizons for performing insitu damage detection and structural health monitoring of a multitude of thin-wall structures.

Posted in: Briefs, Physical Sciences, On-board diagnostics, Vehicle health management, Product development, Non-destructive tests

Acoustic Detection Using Reverberation

Acoustic detection of undersea objects is difficult due to the uncertain environment and even more difficult when the objects are buried in the seabed. First, sediments generate high backscattering noise due to heterogeneous scatters within the sediments, clouding the object.

Posted in: Briefs, Physical Sciences, Remote sensing, Soils, Acoustics, Noise, Marine vehicles and equipment

Process for Testing Aeromedical Equipment

Medical devices are designed to function in environmentally controlled locations, such as stationary hospitals, and not within the harsh, dynamic aircraft environment. Yet, the same medical devices used to care for patients in a hospital environment are often the most capable devices for patient care during transport from one facility to another. These missions are called aeromedical evacuation (AE) missions, and they provide life-sustaining care for a vast array of patients. However, because the devices are designed for a controlled environment, concerns they may adversely affect the operation of aircraft systems must be addressed. Conversely, the aircraft may adversely affect the proper operation and efficacy of the medical equipment. Failure of medical devices during in-flight medical care may result in exposing patients and aircrew to hazardous situations.

Posted in: Briefs, Physical Sciences, Architecture, Medical equipment and supplies, Aircraft operations, Risk assessments, Safety testing and procedures, Rescue and emergency vehicles and equipment

Ultrasonic Guided Wave Analysis for Detecting and Classifying Damage in a Thin Metallic Plate

A ircraft and rotorcraft structures are being redesigned with new lower weight materials; however, older metallic structures continue to be used. These older structures need monitoring and characterization of damage for con-

tinued operation. The use of ultrasonic guided waves is one nondestructive technique that can be used to interrogate such structures. Typically, large cracks or geometric variations can be found by examining signal amplitude,

but smaller damage that can suddenly grow in size and cause serious damage cannot be detected.

Posted in: Briefs, Physical Sciences, Aircraft structures, Aluminum, Fatigue, Acoustics, Inspections

Disposable Chemical Sensor and Wireless Communication Device

A disposable chemical sensor and temperature device has been developed that may be dropped into building rubble or other areas not accessible by rescue personnel to test the environment in the rubble. The system also provides wireless two-way communication and control to obtain information concerning the environment prior to disturbing an area under the rubble, and gives an indication of the likelihood that the area is a candidate for finding survivors. In addition, it would provide two-way communication between a survivor trapped in the rubble and a surface rescue worker, such that a survivor can be alerted to the fact that he or she should make a sound to make his or her presence known.

Posted in: Briefs, Physical Sciences, Sensors and actuators, Wireless communication systems, Chemicals, Rescue operations

Development of an Electrochemical Biosensor for Organophosphate Chemicals

Detection of organophosphate (OP) compounds has attracted much attention in terms of safeguarding human health, owing to their frequent use as pesticides in agriculture and their potential use as chemical warfare agents. Among a variety of biological methods based on the biocatalytic activity of organophosphorus hydrolase (OPH), amperometric, potentiometric, and optical biosensing devices have been developed for detecting OPs. Electrochemical biosensors in particular have been widely investigated to monitor various pesticides including OP compounds such as paraoxon, parathion, sarin, and soman via an enzyme-catalyzed hydrolysis reaction by OPH due to their fast speed, high efficiency, low cost, and small sample size.

Posted in: Briefs, Physical Sciences, Sensors and actuators, Volatile organic compounds, Medical, health, and wellness

Novel Active Transient Cooling Systems

Energy-efficient cooling technology is extremely important in today’s society, considering the need for energy conservation and the urgent need to mitigate global warming. Near-room-temperature magnetic refrigeration is an emerging cooling technology that has several advantages compared to conventional gas-compression technology. It utilizes the magnetocaloric effect (MCE) in which heating and cooling of a magnetocaloric material (MCM) is induced by a varying external magnetic field. The magnetocaloric effect (the temperature change of a magnetic material due to the application of an external magnetic field) is the cornerstone of magnetic cooling.

Posted in: Briefs, Physical Sciences, Energy conservation, Cooling, Magnetic materials

Diode Laser Sensor for Scramjet Inlets

The supersonic combustion ramjet (scramjet) engine is one of the more promising high-speed flight propulsion technologies. One of the reasons for this is the simplicity of the engine design, having no moving parts and requiring no external ignition source, and the fact that scramjets do not need to provide their own oxidizer. Despite this simplicity, several obstacles to the use of scramjet propulsion systems have become apparent, including the ability to produce sufficient fuel-air mixing at high speed, large total pressure losses, reduction in specific impulse with increasing flight Mach number, and the sensitivity of combustion to inlet temperature. This last problem can be very significant.

Posted in: Briefs, Physical Sciences, Lasers, Sensors and actuators, Combustion and combustion processes, Scramjet engines