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⦁ Electrifying railways cuts black carbon exposure by 89%, study finds

⦁ A recipe for sustainable 3D printing

⦁ Concrete in road tunnels decomposes unexpectedly fast

Dehydration sneaks up on you like a silent killer.

One minute you're feeling fine, and the next you're dizzy, cramping, and totally screwed during your workout or workday.

UC Berkeley scientists just created a solution that could change the game - a thin, breathable sweat sensor that tracks your hydration status in real time. And unlike those annoying pee color charts in gym bathrooms, this thing works while you're actually moving.

What's revolutionary about this sensor is how it works.

It measures electrodermal activity (EDA) — basically how electrically conductive your skin is based on how much you're sweating.

Scientists have used EDA for decades to measure psychological stress (like in lie detector tests), but nobody thought it could track physical activity or hydration. Turns out they were wrong.

"This work opens the door to everyday, passive monitoring of hydration and stress using familiar wearable devices like smartwatches," said Ali Javey, the principal investigator of the study

The breakthrough came when the team redesigned the electrodes.

Traditional EDA electrodes trap sweat underneath them, which ruins the measurement during exercise when you're sweating your ass off.

Their solution? Make the electrodes breathable and water-permeable so sweat can pass through them.

No more bulky equipment or disposable patches - just wear your watch and get your data.

The team tested three different types of water-permeable electrodes: micro-lace electrodes, spiral metal wire electrodes, and carbon fiber fabric electrodes.

They put them on different parts of people's bodies and measured signals during both physical activities like cycling and mental tasks like IQ tests.

The results showed that skin conductance actually does reliably reflect how much you're sweating and your overall hydration level, regardless of whether you're stressed mentally or physically exerting yourself.

This could be huge for all kinds of people.

⦁ Athletes could use it to optimize hydration during training and avoid bonking during competition.
⦁ Office workers could monitor stress levels throughout the day to figure out when they need a break.
⦁ Students might use it to track their mental state during study sessions.

The team is now investigating how environmental factors like temperature and humidity affect the signals, which will help make the technology more accurate and personalized.

If you had a watch that could accurately track your hydration levels in real-time, how would you use it?

Would you finally solve your chronic dehydration issues? Use it to optimize your workout performance? Maybe figure out exactly why you get those afternoon headaches?

Reply with your ideas and use cases - we'll feature the most interesting ones in our next newsletter!

Try to guess the engineering term based on these riddles. Ready to play?

Drop your answer and we’ll feature it in the next edition. Fastest one wins!

• Junior Optical Engineer: Indrio Technologies
  Because bending light is easier than bending client expectations.

• Mechanical Design Engineer: BENNING USA
  Design machines so smart, they’ll probably replace you one day.
  

• Senior Tunnel Engineer: LVI Associates
  Digging deep—into the earth and your unresolved life choices.

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