<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><br><div><div>On 06 Oct 2014, at 11:13, Willem Ferguson <<a href="mailto:willemferguson@zoology.up.ac.za">willemferguson@zoology.up.ac.za</a>> wrote:</div><div><br></div>Willem,</div><div><br class="Apple-interchange-newline"><blockquote type="cite"><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 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;">The current position of the black line suggest that it perhaps indicates the equilibrium partial pressure for all inert gases (He + N2) combined?? Similarly, the dark green portion of the bar graph seems to indicate the present combined partial pressures for He + N2. </span></blockquote><div><br></div><div>Indeed, everything is for N2 and He combined.</div><br><blockquote type="cite"><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 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;">But the bar graph surely only pertains to the nitrogen fraction because offgassing for nitrogen and for He follow different patterns, He requiring much longer offgassing times??</span></blockquote><div><br></div><div>Still, it shows N2 plus He as this is what is relevant for Buehlmann-like algorithms.</div><br><blockquote type="cite"><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 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;"> I suspect the gradient factors apply only to the nitrogen partial pressure?</span></blockquote></div><br><div>Again, they apply for the sum. To compute the M-values, you are supposed to take the (weighted by the percentage of the gases) average of the a- and b-parameters. Have a look at the code in deco.c which I hope explains it, see the function <span style="font-family: Menlo; font-size: 11px;">tissue_tolerance_calc specifically.</span></div><div><span style="font-family: Menlo; font-size: 11px;"><br></span></div><div><span style="font-family: Menlo; font-size: 11px;">Best</span></div><div><span style="font-family: Menlo; font-size: 11px;">Robert</span></div></body></html>