<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi all,<div class=""><br class=""></div><div class="">I am still far too busy with work related things (this will hopefully get better next week), so just a few remarks:</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 26.07.2016, at 10:41, Miika Turkia <<a href="mailto:miika.turkia@gmail.com" class="">miika.turkia@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">I guess this is the only exact information we have gathered so far.</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">And of course the DAN recommendations are based on real life testing</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">with clear basis of statistical data, but no algorithms behind them.</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">Other than that, no info on what the no-fly is based on.</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><font face="Menlo-Regular" class=""><span style="font-size: 11px;" class="">[…]</span></font><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""></div></blockquote><br class=""><blockquote type="cite" class=""><div class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">How about using the OSTC method of 60% of desaturation but falling</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">back to DAN recommendation if that value is higher. The DAN</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">recommendations are easy to use even without support from Subsurface,</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">but I like to try to keep the DC happy as well when flying. Right now</span><br style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">it is just guess work, and didn't succeed on my latest attempt :D</span></div></blockquote></div><div class=""><br class=""></div>I had a look at the OSTC source code </div><div class=""><br class=""></div><div class=""><a href="https://bitbucket.org/heinrichsweikamp/hwos_code/src/36a9ac914ce376ec1d1680b61e6c723287e69876/src/p2_deco.c?at=default&fileviewer=file-view-default" class="">https://bitbucket.org/heinrichsweikamp/hwos_code/src/36a9ac914ce376ec1d1680b61e6c723287e69876/src/p2_deco.c?at=default&fileviewer=file-view-default</a></div><div class=""><br class=""></div><div class=""><pre style="margin-top: 0px; margin-bottom: 0px; padding: 0px; font-family: Consolas, Menlo, 'Liberation Mono', Courier, monospace; line-height: 1.4; color: rgb(51, 51, 51);" class=""><span class="kt" style="font-weight: 700; color: rgb(68, 85, 136);">void</span> <span class="nf" style="color: rgb(153, 0, 0); font-weight: 700;">deco_calc_desaturation_time</span><span class="p">(</span><span class="kt" style="font-weight: 700; color: rgb(68, 85, 136);">void</span><span class="p">)</span></pre><div class=""><br class=""></div><div class="">starting in line 1742.</div><div class=""><br class=""></div><div class="">They define desaturation as the point when a tissue is at 5% over the partial pressure at ambient pressure, i.e. the time until then is</div><div class=""><br class=""></div><div class="">log2( (tissue - ambient) / (1.05 * ambient)) * half_time</div><div class=""><br class=""></div><div class="">so it is logarithmic in the ambient pressure and has a natural maximum since a dive without deco violation has a tissue pressure of the surface m-value times GF_HIGH. So this has a natural maximum of a few hours and every factor of 2 of being less oversaturated subtracts a half-time. As you can see from the comments they lowered the value of 5% several times over the development time, starting from 10% which has one half-time less no-flight time for each tissue.</div><div class=""><br class=""></div><div class="">Then the no-flight time is a user configurable (typically 50-60%) percentage. To me, this makes no sense at all since at the end of the no flight time, the amount of gas in your tissues depends on where you started: If you did a heavy deco dive and your tissues are still at the max, according to the formula, it is ok to fly with more gas in your tissues, i.e. be more aggressive. This makes no sense at all to me.</div><div class=""><br class="webkit-block-placeholder"></div><div class="">Physically, this makes no sense to me at all. My guess is it “works” because the possible range of input values (tissue saturations) is quite small, and all you need is a monotonic function that outputs times in the 12-24 hour ball park. And it does not really hurt if you overdo the no-flying. You could probably factor in the phase of the moon and the outcome would not be much different. Or we take the DAN value which officially is a wild guess. </div><div class=""><br class=""></div><div class="">I haven’t had time to read in the proceedings of the DAN workshop that was linked before. What I saw that came most closely to a recommendation was a report of a plan to do a study trying to bend subjects in a simulated fly after dive scenario. Which is not much that could be put into software. Maybe one should check the Rubicon Archive for more scientific information on the issue.</div><div class=""><br class=""></div><div class="">Best</div><div class="">Robert</div><div class="">
<div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class="">-- <br class="">.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oO<br class="">Robert C. Helling Elite Master Course Theoretical and Mathematical Physics<br class=""> Scientific Coordinator<br class=""> Ludwig Maximilians Universitaet Muenchen, Dept. Physik<br class=""> Phone: +49 89 2180-4523 Theresienstr. 39, rm. B339<br class=""> <a href="http://www.atdotde.de" class="">http://www.atdotde.de</a></div><div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""></div><div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Enhance your privacy, use cryptography! My PGP keys have fingerprints</div><div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">A9D1 A01D 13A5 31FA 6515 BB44 0820 367C 36BC 0C1D and</div><div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">DCED 37B6 251C 7861 270D 5613 95C7 9D32 9A8D 9B8F</div><div style="color: rgb(0, 0, 0); font-family: Menlo; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""></div></div></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"><br class="Apple-interchange-newline">
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