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This is a multi-part message in MIME format. ------=_NextPart_000_0414_01C1BF6B.758C0100 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable You are assuming that decompression is a simple, linear process. It is neither. What is happening is that the approximations of making decompression = stops on 10 ft intervals, and rounding stop times up to multiples of one = minute, are introducing errors into the decompression, errors that must = be cleaned up later. In the case of 200 ft vs. 220 ft: observe that the initial delta is 60 = ft in one case and 80 ft in the other. All other things being equal, = the larger initial delta will INITIALLY yield faster offgassing, at a = higher risk of bubbling. Note that the first seven stops are IDENTICAL. = Note also that the first four stops are NOT long enough to allow the = blood to resaturate throughout the body, and so it is not inconceivable = that SOME tissues will require a little more time to offgas. Try running the two dives side-by-side through a deco program that shows = you EVERYTHING that it is taking into account as it models the dive. = You might find it interesting. ----- Original Message -----=20 From: CuteEve@ao*.co*=20 To: techdiver@aquanaut.com=20 Sent: Tuesday, February 26, 2002 11:35 AM Subject: RGBM GF or JF? I see so many questions, doubts, and comments on RGBM that I can't = help=20 putting a big grin on my face. Are we putting our lives on this = so-proven=20 model on mere faith? One instructor showed me a scary comparison made, not against other = models,=20 but on itself.=20 Has anyone else compared the deco at different depth, same time or = same depth=20 different times? Well, this instructor did. On a mix 16/(20-40) % for = a 20=20 minute dive: stop.......220 ft........200 ft 140 ft........1..............1 130...........1..............1 120...........1..............1 110...........1..............1 100...........2..............2 90............2...............2 80............2...............2 70............3...............4 60............4...............4 50............5...............6 40............7...............8 30...........10.............11 =20 20............5...............6 10...........10.............10 total........54.............59min So similar deco profiles for both depths yield a longer deco for 200 = ft than=20 for 220 ft! Give me a break!=20 I understand the "official" explanation for this difference was a = higher=20 degree of "conservatism" due to a higher hit frequency in the = shallower=20 depths......yeah, sure. The model is perfect; it's the divers fault they get bent!=20 How much higher a conservatism? Why does it happen again with 170 ft = and 190=20 ft where a 15 minute dive gives a 33 minute deco for 170 ft while only = 29=20 minute deco on the deeper dive? More conservatism or a higher = "Jeeezzzuz=20 Factor" (JF)? How do you adjust the JF to dive 170 ft for 15 minutes and do a total = 33=20 minute deco or rather dive it for 20 minutes because you only do 32 = minutes=20 deco? You mean a 5 minutes longer stay yields a shorter deco? Yep, = it's right=20 there in the Naui book, Tables pp 3, 4 and 5. See for yourself before = you=20 trust a model with your body. I have seen the outcome. Heck, I can develop my own deco model. I've got a dart board too! BTW Christina, the impropriety of using a government e-mail address = for=20 promoting, selling or private purposes is dealt at a different level. = Not=20 only is improper and unethical, but illegal. I can e-mail you = privately on=20 that if interested. That goes for the private commercial use of = government=20 facilities. But I bet you that at this time, "he is laughing all the = way to=20 the bank". What is a simple taxpayer supposed to do?=20 QTV -- Send mail for the `techdiver' mailing list to = `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to = `techdiver-request@aquanaut.com'. ------=_NextPart_000_0414_01C1BF6B.758C0100 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 5.50.4522.1800" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><FONT face=3DArial size=3D2>You are assuming that decompression is = a simple,=20 linear process.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>It is neither.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>What is happening is that the = approximations of=20 making decompression stops on 10 ft intervals, and rounding stop times = up to=20 multiples of one minute, are introducing errors into the decompression, = errors=20 that must be cleaned up later.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>In the case of 200 ft vs. 220 ft: = observe that the=20 initial delta is 60 ft in one case and 80 ft in the other. All = other=20 things being equal, the larger initial delta will INITIALLY yield faster = offgassing, at a higher risk of bubbling. Note that the first = seven stops=20 are IDENTICAL. Note also that the first four stops are NOT long = enough to=20 allow the blood to resaturate throughout the body, and so it is not=20 inconceivable that SOME tissues will require a little more time to=20 offgas.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Try running the two dives side-by-side = through a=20 deco program that shows you EVERYTHING that it is taking into account as = it=20 models the dive. You might find it interesting.</FONT></DIV> <BLOCKQUOTE=20 style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV> <DIV=20 style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black"><B>From:</B>=20 <A title=3DCuteEve@ao*.co* = href=3D"mailto:CuteEve@ao*.co*">CuteEve@aol.com</A>=20 </DIV> <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A = title=3Dtechdiver@aquanaut.com=20 href=3D"mailto:techdiver@aquanaut.com">techdiver@aquanaut.com</A> = </DIV> <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Tuesday, February 26, = 2002 11:35=20 AM</DIV> <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> RGBM GF or JF?</DIV> <DIV><BR></DIV>I see so many questions, doubts, and comments on RGBM = that I=20 can't help <BR>putting a big grin on my face. Are we putting our lives = on this=20 so-proven <BR>model on mere faith?<BR>One instructor showed me a scary = comparison made, not against other models, <BR>but on itself. <BR>Has = anyone=20 else compared the deco at different depth, same time or same depth=20 <BR>different times? Well, this instructor did. On a mix 16/(20-40) % = for a 20=20 <BR>minute dive:<BR>stop.......220 ft........200 ft<BR>140=20 = ft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total........54.............59min<BR>So=20 similar deco profiles for both depths yield a longer deco for 200 ft = than=20 <BR>for 220 ft!<BR>Give me a break! <BR>I understand the "official"=20 explanation for this difference was a higher <BR>degree of = "conservatism" due=20 to a higher hit frequency in the shallower <BR>depths......yeah, = sure.<BR>The=20 model is perfect; it's the divers fault they get bent! <BR><BR>How = much higher=20 a conservatism? Why does it happen again with 170 ft and 190 <BR>ft = where a 15=20 minute dive gives a 33 minute deco for 170 ft while only 29 <BR>minute = deco on=20 the deeper dive? More conservatism or a higher "Jeeezzzuz <BR>Factor"=20 (JF)?<BR><BR>How do you adjust the JF to dive 170 ft for 15 minutes = and do a=20 total 33 <BR>minute deco or rather dive it for 20 minutes because you = only do=20 32 minutes <BR>deco? You mean a 5 minutes longer stay yields a shorter = deco?=20 Yep, it's right <BR>there in the Naui book, Tables pp 3, 4 and 5. See = for=20 yourself before you <BR>trust a model with your body. I have seen the=20 outcome.<BR>Heck, I can develop my own deco model. I've got a dart = board=20 too!<BR><BR>BTW Christina, the impropriety of using a government = e-mail=20 address for <BR>promoting, selling or private purposes is dealt at a = different=20 level. Not <BR>only is improper and unethical, but illegal. I can = e-mail you=20 privately on <BR>that if interested. That goes for the private = commercial use=20 of government <BR>facilities. But I bet you that at this time, "he is = laughing=20 all the way to <BR>the bank". What is a simple taxpayer supposed = to do?=20 <BR>QTV<BR>--<BR>Send mail for the `techdiver' mailing list to <A=20 = href=3D"mailto:`techdiver@aquanaut.com'">`techdiver@aquanaut.com'</A>.<BR= >Send=20 subscribe/unsubscribe requests to <A=20 = href=3D"mailto:`techdiver-request@aquanaut.com'">`techdiver-request@aquan= aut.com'</A>.</BLOCKQUOTE></BODY></HTML> ------=_NextPart_000_0414_01C1BF6B.758C0100-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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