RSS feed source: Centers for Disease Control and Prevention--Office of Public Health Preparedness and Response
Paper examines 9/11-related health outcomes and lessons learned since the disaster.
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RSS feed source: Centers for Disease Control and Prevention--Office of Public Health Preparedness and Response
NIST experts are working to bring our measurements out of the lab and to the places where our users need them — saving time and money.
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RSS feed source: Centers for Disease Control and Prevention--Office of Public Health Preparedness and Response
Plug a phone into a modern charger and the first 10 minutes are impressive. The next 20 are not.
This is not a defect. It’s the connected device protecting itself. As temperature rises during charging, a smartphone’s battery management system reduces the current it will accept, because heat accelerates the chemical degradation that permanently reduces battery capacity. The charger may be capable of delivering more, but the device simply stops taking it.
For anyone building products in the portable power category, this creates an uncomfortable gap between specification and experience. A device rated at 25 watts is accurate in the sense that it can deliver 25 watts. Whether it delivers 25 watts for the duration of a charge is a different question, and one the specification does not answer.
The specification gap
The gap matters commercially because it is invisible at the point
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RSS feed source: Centers for Disease Control and Prevention--Office of Public Health Preparedness and Response
Throughout the history of the computer chip, engineers have treated waste heat as an inevitable cost of a calculation. Hannah Earley, however, thinks it’s a design choice. Earley, 31, is cofounder and chief technology officer of Vaire Computing, a startup building chips that recycle energy usually thrown away as heat—a strategy known as reversible computing. Ultimately, she thinks, this approach could help make data centers (and our laptops and phones) much more energy efficient.
When conventional computer chips perform calculations, they erase the information they no longer need along the way, dissipating energy as heat in the process. Earley compares the approach to racing through a city only to pump the brakes at every intersection: The car loses momentum and must burn more fuel to accelerate again. Reversible computing aims to keep the momentum going—instead of erasing information from the intermediate steps in a
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