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Gizmorama - August 15, 2016

Good Morning,


Have you been search for a way of splitting a sound into its basic frequencies? Me too! Well, look no further. Scientists have developed an acoustic prism for just such an occasion.

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin


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*-- Scientists invent new type of 'acoustic prism' --*

LAUSANNE, Switzerland - Scientists in Switzerland have invented an "acoustic prism" capable of splitting a sound into its basic frequencies.

Like an optical prism, which relies on the physical property of refraction, the newly invented acoustic prism dissects sound using only physical properties. Unlike an optical prism, which can be found in nature, the acoustic prism is man-made.

The prism takes the form of a rectangular tube of aluminum with ten evenly spaced and neatly aligned holes cut through it. When a sound is directed at one end of the prism, its constituent frequencies are split up. Higher frequencies are siphoned through the closest holes, while lower frequencies are pulled into the holes farther down.

The split sound waves are dispersed as they travel through and across the prism. The angle of dispersion depends on the frequencies split through each hole.

Tests showed the prism can be used as an antenna. The frequency of a the main component of a sound reveals from which direction it came.

"The principle of the acoustic prism relies on the design of cavities, ducts and membranes, which can be easily fabricated and even miniaturized, possibly leading to cost-effective angular sound detection without resorting to expensive microphone arrays or moving antennas," researchers wrote in a news release.

The novel research was detailed in a new paper, published this week in the Journal of the Acoustical Society of America.

Researchers believe the device could inspire a new generation of mixed radar-sonar technologies.



*-- New technique to improve perovskite solar cells --*

GOLDEN, Colo. - A team of researchers from the United States and China have found a way to make perovskite solar cells more efficient and dependable.

By treating hybrid halide perovskite solar cells with a methyl ammonium bromide solution, researchers minimized material defects and improved performance. The production technique resulted in a boost to the cells' sunlight conversion efficiency.

Perovskite solar cells have seen marked improvement in their conversion efficiency in recent years, but inconsistencies in the production process and disparity in the skills of lab technicians have resulted in widely varying cell performances.

Without the new technique, most cells feature an efficiency ranging from 15 to 20 percent. The new technique ensures an efficiency of 19 percent.

The application of the methyl ammonium bromide solution triggers what's called the Ostwald ripening process, whereby smaller crystals are dissolved and deposited onto bigger crystals. The process ensures consistent, pinhole-free perovskite films.

Other methods for growing perovskite cells are less foolproof, and require a great deal of timing. As a result, cells often end up with defective, non-uniform crystals or holes in the film.

"This new chemical approach enhances processing tolerance to the initial perovskite film quality and improves the reproducibility of device fabrication," researchers wrote in their paper on the breakthrough, published this week in the journal Nature Communications.

The research was carried out by scientists a the Department of Energy's National Renewable Energy Laboratory and Shanghai Jiao Tong University.

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