Thermal noise used to send data without an active signal - Stanford Report

We’re sharing this article early to provide faster access to peer-reviewed, accepted research. It is citable and carries a permanent DOI. This version is subject to further edits and will be replaced automatically by the final Version of Record. All legal disclaimers apply. AbstractUnderstanding the mechanical behavior of frozen unsaturated sand under thermal gradients is crucial for the design and maintenance of infrastructure in permafrost regions. In this study the shear strength of Ottawa sand under varying temperatures, degrees of saturation, and loading conditions is investigated. A series of laboratory experiments were performed to measure the shear strength of Ottawa sand using direct simple shear equipment placed in a temperature controlled environmental chamber. During the experiments, soil temperatures and stress–strain curves were recorded, and they were analyzed to determine the strength behavior. Results show that shear strength increases with decreasing temperature, increasing ice content, strain rate, and normal stress.

We’re sharing this article early to provide faster access to peer-reviewed, accepted research. It is citable and carries a permanent DOI. This version is subject to further edits and will be replaced automatically by the final Version of Record. All legal disclaimers apply. AbstractUnderstanding the mechanical behavior of frozen unsaturated sand under thermal gradients is crucial for the design and maintenance of infrastructure in permafrost regions. In this study the shear strength of Ottawa sand under varying temperatures, degrees of saturation, and loading conditions is investigated. A series of laboratory experiments were performed to measure the shear strength of Ottawa sand using direct simple shear equipment placed in a temperature controlled environmental chamber. During the experiments, soil temperatures and stress–strain curves were recorded, and they were analyzed to determine the strength behavior. Results show that shear strength increases with decreasing temperature, increasing ice content, strain rate, and normal stress.

Stanford researchers recently revealed how a seemingly physics-defying wireless communication technology works. The new technology, called thermal noise communication, harnesses background static that normally is the bane of radio, cellular, and other wireless signals. In a new study published in Proceedings of the National Academy of Sciences, the team showed how a transmitter could deliver data to a receiver without any actively produced signal by manipulating tiny oscillations in voltage. The findings describe how the system works at a fundamental level, opening the door to improving the communication mode and determining real-world applications for it. "We've built a system that others could very easily implement," said senior author Zerina Kapetanovic, an assistant professor of electrical engineering. A physics mysteryIn her previous research at the University of Washington, Kapetanovic studied agricultural sensing technologies, which inspired her to pursue low-power modes of relaying data like soil moisture levels.

Two birds in Brazil are, scientifically speaking, loud as heck, So loud that these relatively small birds rival the earsplitting obnoxiousness of machinery like jackhammers and chainsaws. They’re even louder than much larger animals, like elephants. According to a study published in Evolution, researchers from the University of Massachusetts Amherst hiked into the Brazilian wilderness armed with laser rangefinders and portable sound level meters to measure the song volume of 123 different species. While hummingbirds let out a gentle 50 to 64 decibels, about on par with a normal conversation, the bare-throated bellbird and the red-legged seriema seemed to be trying to tear a hole in the universe with their birdsong.