Summary: News From seawater to drinking water, with the push of a button | TechXPlore (01:04) MIT researchers have developed a portable desalination unit, weighing less than 10 kilograms, that can remove particles and salts to generate drinking water.Suitcase-sized device Requires less power to operate than a cell phone charger Can be powered by a small, portable solar panel, which can be purchased online for around $50. Generates drinking water that exceeds World Health Organization quality standards. Runs with the push of one button. Unlike other portable desalination units that require water to pass through filters, this device utilizes electrical power to remove particles from drinking water. Eliminating the need for replacement filters Relies on a technique called ion concentration polarization (ICP) Rather than filtering water, the ICP process applies an electrical field to membranes placed above and below a channel of water. The membranes repel positively or negatively charged particles—including salt molecules, bacteria, and viruses—as they flow past. The process removes both dissolved and suspended solids, allowing clean water to pass through the channel. Once the salinity level and the number of particles decrease to specific thresholds, the device notifies the user that the water is drinkable. This filterless process enables the unit to be deployed in remote and severely resource-limited areas, such as communities on small islands or aboard seafaring cargo ships.Their prototype generates drinking water at a rate of 0.3 liters per hour, and requires only 20 watts of power per liter. Researchers develop a paper-thin loudspeaker | MIT News (06:21) MIT engineers have developed a paper-thin loudspeaker that can turn any surface into an active audio source.Produces sound with minimal distortion while using a fraction of the energy required by a traditional loudspeaker. Weighing about as much as a dime and can generate high-quality sound no matter what surface the film is bonded to. The new loudspeaker simplifies the speaker design by using a thin film of a shaped piezoelectric material that moves when voltage is applied over it, which moves the air above it and generates sound. Most thin-film loudspeakers are designed to be freestanding because the film must bend freely to produce sound. If the thin speaker needs to be bound to a surface that would impede the sound generation process. To overcome this problem , their design relies on tiny domes on a thin layer of piezoelectric material which each vibrate individually. The researchers pioneered a deceptively simple fabrication technique, which requires only three basic steps and can be scaled up to produce ultrathin loudspeakers. Lead author Jinchi Han talks on the process:“This is a very simple, straightforward process. It would allow us to produce these loudspeakers in a high-throughput fashion if we integrate it with a roll-to-roll process in the future. That means it could be fabricated in large amounts, like wallpaper to cover walls, cars, or aircraft interiors” They tested their thin-film loudspeaker by mounting it to a wall 30 centimeters from a microphone to measure the sound pressure level, recorded in decibels. When 25 volts of electricity were passed through the device at 1 kilohertz, the speaker produced high-quality sound at conversational levels of 66 decibels. At 10 kilohertz, the sound pressure level increased to 86 decibels, about the same volume level as city traffic. Another cool feature of this thin speaker is it can be used effectively for ultrasound applications, like imaging.Because the tiny domes are vibrating, rather than the entire film, the loudspeaker has a high enough resonance frequency for ultrasound imaging Could use it to detect where a human is standing in a room, just like bats do using echolocation, and then shape the sound waves to follow the person as they move. This device has many possible applications:Provide ac
