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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Publish or (gulp) Perish
>> Powerpoints have a hard time matching the depth of a refereed journal >> submission, because with the powerpoint, soundbites tend to take >> precedence over content. >Attention to sidebar on page 192 of the Columbia Accident >Investigation Board report entitled "Engineering by Viewgraphs": >http://www.nasa.gov/columbia/caib/PDFS/VOL1/PART02.PDF Everybody who makes slide presentations should read this. I know it has influenced me in trying to make my presentations clearer and shorter and more precise. If you read nothing else from the report, have a look at this slide reproduced below as close as possible to the way it originally appeared including line breaks and bulleted indentation: Review Of Test Data Indicates Conservatism for Tile Penetration --------------------------------------------------- * The existing SOFI on tile test data used to create Crater was reviewed along with STS-107 Southwest Research data - Crater overpredicted penetration of tile coating significantly * Initial penetration to described by normal velocity - Varies with volume/mass of projectile(e.g., 200ft/sec for 3cu. In) * Significant energy is required for the softer SOFI particle to penetrate the relatively hard tile coating - Test results do show that it is possible at sufficient mass and velocity * Conversely, once tile is penetrated SOFI can cause significant damage - Minor variations in total energy (above penetration level) can cause significant tile damage - Flight condition is significantly outside of test database * Volume of ramp is 1920cu in vs 3 cu in for test The Columbia investigators zeroed in on the words "significant" and "significantly" used 5 times on the slide with meanings varying from "detectable in largely irrelevant calibration case study" to "an amount of damage so that everyone dies" to "a difference of 640-fold." None of these 5 usages appears to refer to the technical meaning of "statistical significance." They also noted that the low resolution of a slide promotes the use of compressed phrases like "Tile Penetration" whose meaning can be ambiguous and usually is never defined. The slide alludes to the idea of damage to the tiles but often avoids saying it directly referring to "penetration" or "it" and using unclear sentence fragments. If you do want to see the original it is on page 95 of the PDF file linked above. --Michael Dillon
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