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One more point to add here...Having been deployed on a submarine and forced to observe analog gages for extended periods of time, I can see where time spent finding ways to reduce eye strain while making these long observations would be time well spent. Periodic glances at such a gage are normally not a problem, but during short periods of questionable depth control for example, one is almost fixated on this particular dial until the boat starts going shallower. Large letterings and significant points of interest are also a great idea to reduce this strain. David Bartsch > Date: Sun, 13 Dec 2009 17:35:08 -0500 > From: jonw@psubs.org > To: personal_submersibles@psubs.org > Subject: Re: [PSUBS-MAILIST] Acrylic View Ports vs. long-wave UV-Light > > Jens, > > A couple of points regarding your original question. I haven't been > able to find any documentation suggesting that UV is an issue with > acrylic. In fact, acrylic can be manufactured to absorb UV and prevent > transmission through it > (http://www.eplastics.com/Plastic/Plastics_Library/UV-Ultra-Violet-Filtering-Plexiglass). > This is not just a layer simply applied to the outside surface, but > built into the acrylic material throughout. > > On page 48 of Stachiw's Handbook of Acrylics, section 2.7, second > paragraph, he states: "<acrylic> is virtually unsurpassed in its > resistance to outdoor weathering. This property, coupled with color > retention, accounts for acrylic's dominance in the outdoor sign market. > Signs of acrylic are commonly guaranteed to be weather resistant for > more than 15 years." While not a definitive statement, this would > certainly lead one to believe that UV effect on acrylic is not a major > issue. Acrylic is a common replacement for safety glass in house doors > and windows and survive years in the suns UV rays. All anecdotal of > course, however in the absence of a definitive statement to the contrary > my guess is that the amount of indirect UV energy from a 30ma UV led is > not going to be an issue for the thickness of acrylic that are going to > be in place on a small submarine. > > Jon > > > > > > ************************************************************************ > ************************************************************************ > ************************************************************************ > The personal submersibles mailing list complies with the US Federal > CAN-SPAM Act of 2003. Your email address appears in our database > because either you, or someone you know, requested you receive messages > from our organization. > > If you want to be removed from this mailing list simply click on the > link below or send a blank email message to: > removeme-personal_submersibles@psubs.org > > Removal of your email address from this mailing list occurs by an > automated process and should be complete within five minutes of > our server receiving your request. > > PSUBS.ORG > PO Box 53 > Weare, NH 03281 > 603-529-1100 > ************************************************************************ > ************************************************************************ > ************************************************************************ > Hotmail: Free, trusted and rich email service. Get it now. |