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Let’s Stop Using Ankle Bracelets to Monitor Offenders

Smartphones do a better job and allow for positive reinforcement and incentives

12 min read
Opening photo for this feature article.
Photo: Ted Polumbaum/Newseum

photo of person wearing an ankle bracelet while sitting in chair Photo: The Voorhes

Imagine this: It’s early morning, and you’re sleeping alone in your bed. Suddenly your ankle vibrates, and a voice blurts out from beneath the sheets: “This is the monitoring center. You are not in your inclusion zone. Do you have permission to be outside this area?”

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A Transistor for Sound Points Toward Whole New Electronics

“Topological” acoustic transistor suggests circuits with dissipationless flow of electricity or light

3 min read
Model of a honeycomb lattice

Model of a honeycomb lattice that serves as the basis for a "transistor" of sound waves—whose design suggests new kinds of transistors of light and electricity, made from so-called topological materials. Electrons in a topological transistor, it is suspected, would flow without any resistance.

Hoffman Lab/Harvard SEAS

Potential future transistors that consume far less energy than current devices may rely on exotic materials called "topological insulators" in which electricity flows across only surfaces and edges, with virtually no dissipation of energy. In research that may help pave the way for such electronic topological transistors, scientists at Harvard have now invented and simulated the first acoustic topological transistors, which operate with sound waves instead of electrons.

Topology is the branch of mathematics that explores the nature of shapes independent of deformation. For instance, an object shaped like a doughnut can be deformed into the shape of a mug, so that the doughnut's hole becomes the hole in the cup's handle. However, the object couldn't lose the hole without changing into a fundamentally different shape.

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Taking Cosmology to the Far Side of the Moon

New Chinese program plans to use satellites in lunar orbit to study faint signals from early universe

3 min read
crescent moon
Darwin Fan/Getty Images

A team of Chinese researchers are planning to use the moon as a shield to detect otherwise hard-to-observe low frequencies of the electromagnetic spectrum and open up a new window on the universe. The Discovering the Sky at the Longest Wavelengths (DSL) mission aims to seek out faint, low-frequency signals from the early cosmos using an array of 10 satellites in lunar orbit. If it launches in 2025 as planned, it will offer one of the very first glimpses of the universe through a new lens.

Nine “sister” spacecraft will make observations of the sky while passing over the far side of the moon, using our 3,474-kilometer-diameter celestial neighbor to block out human-made and other electromagnetic interference. Data collected in this radio-pristine environment will, according to researchers, be gathered by a larger mother spacecraft and transmitted to Earth when the satellites are on the near side of the moon and in view of ground stations.

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Adhesives Gain Popularity for Wearable Devices

Adhesive formulations help with challenging assembly of wearables and medical sensors

3 min read

A major challenge in wearable device assembly is to maximize the reliability of embedded circuits while keeping the package thin and flexible.

Shutterstock

This is a sponsored article brought to you by Master Bond.

Master Bond adhesive formulations provide solutions for challenging assembly applications in manufacturing electronic wearable devices. Product formulations include epoxies, silicones, epoxy-polyurethane hybrids, cyanoacrylates, and UV curing compounds.

There are some fundamental things to consider when deciding what is the right adhesive for the assembly of electronic wearable devices. Miniaturization of devices, and the need to meet critical performance specifications with multiple substrates, require an analysis of which chemical composition is most suitable to satisfy the required parameters.

These preliminary decisions are often predicated on the tradeoffs between different adhesive chemistries. They may vary widely, and in many cases are essential in achieving the needed goals in adhering parts and surfaces properly.

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