Agile RF Systems (United States)

The primary focus of this paper is to present the results from outdoor acoustic measurements from a rocket engine hot fire test. The two objectives of the test were to quantify the overall sound pressure level at large distances from engine to quantify the impact of the events on the surrounding community, and to better understand the source distribution in the engine plume. Microphone arrays were positioned around the property to be able to capture the sound propagation, estimate source levels, and conduct phased array-based plume source localization.

Caffeine is an integral part of beverages, food, and medications. Severe intoxication of caffeine is rare, and reports are even scarcer. However, over-the-counter, unregulated sale of performance-enhancing compounds, such as caffeine, turns high-dose consumption into a real concern. Severe intoxication may be fatal, usually by malignant cardiac arrhythmia. We report a case of a 23-year-old university student who accidentally consumed about 100 times the amount present in an expresso of anhydrous caffeine.

Using ultra-wideband (UWB) impulse radar for detecting and tracking fast-moving small targets over the ocean surface has been considered before with limited applications. The challenges of deploying such radar sensors on small, unmanned marine platforms are addressed in this study. The first challenge is the stringent size and weight requirement to allow a tracking radar sensor to be fitted into the payload of a small unmanned surface vehicle (USV). For the first time, we implemented a design that is based on a single chip UWB radar sensor operating at X-band, which effectively achieves the size and weight requirement for a small USV payload. The second challenge is range extension and range ambiguity resolution. With the UWB radar operating various high-PRF modes, we developed a novel approach that stitches together range profiles from multiple PRFs, to extend the effective non-ambiguous range at the cost of scan speed. The third challenge is developing a lowcost, ultra-wideband planar antenna and front-end, which is also part of the USV payload and needs to be able to perform either sector scanning, or even electronic scanning, with a very low profile. We have successfully designed and implemented one such antenna using a dipole array design. By integrating the solutions into a complete system, we have performed a series of lab and outdoor tests of the UWB radar sensor and obtained some promising target data. Simulations are also being developed for testing the potential target signatures and tracking effectiveness of moving targets over ocean surface clutter environments.

There is a significant need for portable, low-cost, and multi-functional ground and airborne radars. In some applications, the goal is to integrate multiple functions within a limited and constrained frequency band. For other applications, however, the challenge is how to support multiple missions that have been associated with separated frequency bands. This study considers the feasibility of two possible solutions for multifunction radar: the multi-band, agile frequency diversity radar, and a broad-band, common radar aperture. For either of the solutions, the goal is to find the optimal architectures and enabling technologies that support the integration of the following mission requirements: (1) automatic precise landing support, (2) counter-threat detection (such as counter-drone) in ground and airborne operations, (3) 3Daltitude- finding, (4) portable local weather surveillance. We investigated the basic requirements of each of these missions and summarized the trade analysis results. Next, we investigated the current enabling technologies for two proposed aperture options, especially regarding the design of radiating elements. Multiple antenna element designs were studied, which show promise for meeting multi-band or broadband aperture needs. A simulation verification based on the Phased Array System Simulator (PASIM) technology, which was jointly developed with MathWorks, is introduced. The simulation serves as a method to evaluate the quality of performance (QoP) of different radar missions that can be achieved with specific architectures. We investigated a mixed-signal transceiver and GPU-enabled backend software system that allows for the parallel execution of multiple radar missions through the same aperture.

Stress causes a major effect on several systems of the body, including cardiovascular, digestive and immune systems. Behavioral signs also reflect stressful condition. Exercise and a good social network are believed to lower stress. We used dogs kenneled in a humane society as a model to study the effect of exercise and socialization on stress‐related symptoms. We measured behavioral signs of stress including but not limited to scratching, distress whining and exaggerated grooming Research shows a relationship between stress and elevated cortisol levels. We measured salivary cortisol as a biochemical measure of stress. Dogs were allowed to acclimatize to shelter conditions. The experiment was conducted over four days with 40 dogs. The experimental group consisting of 20 dogs, were allowed to play and socialize for 30 minutes, whereas control dogs stayed in their kennels. Salivary cortisol and behavioral indices were measured before and after exercise play session. Dogs that played and had social contact showed less stressful behaviors as well as lower cortisol levels. Our studies suggest that physical activity and social contact alleviates stress.