The power needed to run the filter can be provided by any device that can provide 20 volts, such as a small solar panel.

CNN: Nanotech and 'tea bag' to clean up drinking water

Non-Google app stores that currently run on China-based Android devices filter out apps that violate Chinese regulations.

WSJ: Google Renews Push in China

By contrast, energy companies run their turbines continuously at constant speeds and filter the air intake against damaging particles.

FORBES: Energy