Category Physics

Scientists Unveil Fire-Safe Fuel. It Won’t Burn Without Electric Current

Firefighters trying to extinguish a vehicle fire at a gas station. (Thomas Hawk)

UC Riverside chemical engineers have designed a fuel that ignites only with the application of electric current. Since it doesn’t react to flames and cannot start accidental fires during storage or transport, it is a “safe” liquid fuel.

“The fuel we’re normally using is not very safe. It evaporates and could ignite, and it’s difficult to stop that,” said Yujie Wang, UCR chemical engineering doctoral student and co-author of a new paper about the fuel. “It is much easier to control the flammability of our fuel and stop it from burning when we remove voltage.”

The Journal of the American Chemical Society paper describes how the team created the fuel, and additional technical details are also included i...

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MilliMobile is a Tiny, Self-driving Robot Powered only by Light and Radio Waves

MilliMobile is a tiny, self-driving robot powered only by light and radio waves
Researchers at the University of Washington have created MilliMobile, a tiny, self-driving robot powered only by surrounding light or radio waves. It’s about the size of a penny and can run indefinitely on harvested energy. Credit: Mark Stone/University of Washington

Small mobile robots carrying sensors could perform tasks like catching gas leaks or tracking warehouse inventory. But moving robots demands a lot of energy, and batteries, the typical power source, limit lifetime and raise environmental concerns. Researchers have explored various alternatives: affixing sensors to insects, keeping charging mats nearby, or powering the robots with lasers. Each has drawbacks: Insects roam, chargers limit range, and lasers can burn people’s eyes.

Researchers at the University of Washington ...

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Thermal MagIC: Digging into the Details of an Ambitious New ‘Thermometry Camera’

Diagram of the series of tiny wells and the magnetic particle image itself
Left: Diagram of the series of tiny wells, in clusters of fours, filled with solution. Each well in a foursome is spaced away from the other wells by a certain amount, anywhere from 0.1 mm (very close together) to 1 mm (further apart). Right: The magnetic particle image itself, showing distinctions between the wells spaced farther apart but not between the wells spaced close together. The dashed red circle in both images shows the foursome of wells spaced 0.5 mm apart.
Credit: NIST

Thermometers can do a lot of things: Measure the temperature at the center of your perfectly braised chicken or tell you whether to keep your child home from school due to illness. But because of their size, traditional thermometers’ uses are still limited.

“How do you non-invasively measure a temperature...

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Machine Learning Models can produce Reliable Results even with Limited Training Data

Machine learning models can produce reliable results even with limited training data
Elliptic PDE learning methods can be data-efficient. Credit: Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2303904120

Researchers have determined how to build reliable machine learning models that can understand complex equations in real-world situations while using far less training data than is normally expected.

The researchers, from the University of Cambridge and Cornell University, found that for partial differential equations—a class of physics equations that describe how things in the natural world evolve in space and time—machine learning models can produce reliable results even when they are provided with limited data.

Their results, reported in the Proceedings of the National Academy of Sciences, could be useful for constructing more t...

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