domingo, 27 de janeiro de 2013

Nepal Human Hair Solar Panel Hoax

Para aprendermos que nem tudo o que se lê é necessariamente verdade (em resposta a um post anterior).

Excerto retirado do site pessoal de Edward Hyatt (para ver mais clicar no link):

"My PhD is in Organic Materials for Photovoltaics... I am horrified that [news agencies] have published this article verbatim, without even questioning the basic science behind this 'invention'... Melanin is really bad at charge separation, a basic requirement for solar cells." ~~Caesar_Dia

An article appeared in the Daily Mail claiming that an 18-year-old Nepalese studentMilan Karki and colleagues invented a solar panel capable of generating 9VDC/18W with human hair as the main component. However, test results and analysis of quotes from the inventor show this invention to be a hoax. The idea that human hair can be used as a solar cell has long been debunked but continues to be circulated on so-called "free energy" or "zero point energy" blogs and eco blogs. Claims on these blogs are based on confusion about the nature of static electricity and misinterpretation of research on melanin's electro-optical and semiconductor properties. The solar panel design is based on the students' misinterpretation of preliminary unpublished results they found on the internet. The students make the false claim that hair is a conductor and generates a voltage when exposed to light.

What has really happened? The Trinity College students made a cuprous oxide solar cell that is commonly used for demonstrations in school laboratories. This cell does indeed generate a small voltage and current, but is completely impractical to scale to a larger size, and the cell would work just fine without human hair. A reporter with no training in science or engineering witnessed the cuprous oxide cell working but didn't realize it wasn't generating the claimed power levels. The story was broken without being reviewed by experts, however now most news outlets are retracting the story based on feedback from scientists and engineers.

In the remainder of this article, we examine this story in detail, starting with how the story spread and why it spread. Then, we discuss the technical details of this invention and how it measures up to current science. Then we elaborate reasons for calling the invention a "hoax" based on information published so far and quotes from the inventor himself. The article ends with remarks directed at the inventor and some suggestions for more fruitful research areas. The article provides an alternative and perhaps more feasible solution in the form of a small thermoelectric generator that can be powered either by the sun or captured heat from cooking coals. (...)"

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