Emilio Segrè Visual Archives

More than 30,000 photos of scientists and their work

Attention ESVA patrons:

The Emilio Segrè Visual Archives’ site is moving soon and adopting an open access approach to digital image sharing. Once we have transitioned to the new site in 2021, we will no longer charge for our high-resolution digital images or usage fees (note that we do not hold copyright to all the images in our collections and you will still need to obtain permission for those which we do not own).

If you are working on a long-term project, we advise you to wait until the migration is complete so that you may obtain our copies for free. If you cannot wait, email us at nbl [at] aip.org and we will do what we can to assist you. We will not be offering refunds for past purchases.

For more information, please visit our FAQ page on the Ex Libris Universum blog. 

General Electric F24

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General Electric F24

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We charge a usage fee per photo if the photo is published, reproduced in a product or publicly exhibited. This is not a license in the legal sense. As a non-profit institution, we do not make any money providing these photographs. It is only by assessing usage fees that we are able to cover the cost of providing publication quality copies of our photos, preserving the photograph collection according to archival standards, and providing access to the collection by maintaining an online image database. The copyright holder may charge a fee in addition to our service fee.

Images are for use in educational projects only and must be used in a respectful manner.

Image title: 
Unidentified personnel giving a "physical exam" to a compressor coming off the assembly line
Credit line: 
General Electric Research and Development Center, courtesy AIP Emilio Segrè Visual Archives, Physics Today Collection

As compressors (the key component of air conditioners) come off the assembly lines at General Electric's room air conditioner plant in Louisville, Ky., they have to pass a stringent "physical exam" administered by an electronic "physician." The automated inspection system - invented at the GE Research and Development Center in Schenectady, N.Y. and fine-tuned for the factory floor with the assistance of the plant's engineers - consists of a super-sensitive "stethoscope" connected to a powerful minicomputer. Just as a doctor listens to a patient's heartbeat, the acoustic sensor picks up the otherwise inaudible whirrs, squeals, and clicks made by the compressor as its shaft is unp briefly. The minicompter, located elsewhere in the factory, quickly compares these sounds with the acoustic "fingerprint" of a "good" compressor stored in its memory and decides if they match. If they don't, a display lights up to tell an operator that the unit should be lifted off the line. The complete "physical", which involves millions of mathematical calculations, takes just six seconds.

Man in the photo is unidentified. 

Photo date: 
August 9, 1983
Original format: 
1 photographic print (black and white; 9.5 x 7.5 inches)
General Electric Research Laboratory