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This is a multi-part message in MIME format. ------=_NextPart_000_0017_01C09B5F.7EA33F00 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Helium is lighter (less dense)than air, and therefore it conducts heat = much more quickly. This is the reason you do not inflate your drysuit = with backgas. Use an independent inflation system with argon or air = (argon is very dense and therfore insulates well). =20 To answer your physics question: c =3D the specific heat of a gas (the amount of heat necessary to change = 1 kg of the substance 1 degree celcius) This would be helpful (in that shoot yourself in the foot kind of way) = to calculate the joules of body heat you're gonna lose if you fill your = drysuit with He instead of Ar or Air. =20 -CB From: moorea(uol)=20 To: techdiver@aquanaut.com=20 Sent: Tuesday, February 20, 2001 8:05 AM Subject: Helium thermal properties Hello all !=20 I=B4ve been diving since 86, and nowadays i made my own mixes, but = now, i decided to go certified. My instructor, talking about thermal loss in a trimix class, explain = me that the heat exchange is a direct relationship with gas density. I=B4ve read and learn in the past (including in phisics class at = regular school) that heat exchange depends of thermal conductivity of = the media (Q =3D mc delta t) where "c" is the thermal conductivity. Can you help me with that ? Am i right ? thanks=20 Marcelo Moorea ------=_NextPart_000_0017_01C09B5F.7EA33F00 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 5.50.4134.600" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV> <DIV><FONT face=3DArial size=3D2>Helium is lighter (less dense)than air, = and=20 therefore it conducts heat much more quickly. This is the reason = you do=20 not inflate your drysuit with backgas. Use an independent = inflation system=20 with argon or air (argon is very dense and therfore insulates = well). =20 </FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>To answer your physics = question:</FONT></DIV> <DIV><FONT face=3DArial size=3D2>c =3D the specific heat of a gas (the = amount of heat=20 necessary to change 1 kg of the substance 1 degree celcius)</FONT></DIV> <DIV><FONT face=3DArial size=3D2>This would be helpful (in that shoot = yourself in=20 the foot kind of way) to calculate the joules of body heat you're gonna = lose if=20 you fill your drysuit with He instead of Ar or Air. = </FONT></DIV> <DIV><FONT face=3DArial size=3D2>-CB</FONT></DIV></DIV> <BLOCKQUOTE dir=3Dltr=20 style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV=20 style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: = black"><B>From:</B>=20 <A title=3Dmoorea@uo*.co*.br* = href=3D"mailto:moorea@uo*.co*.br*">moorea(uol)</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 20, = 2001 8:05=20 AM</DIV> <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Helium thermal = properties</DIV> <DIV><BR></DIV> <DIV><FONT face=3DArial size=3D2>Hello all ! </FONT></DIV> <DIV><FONT face=3DArial size=3D2>I=B4ve been diving since 86, and = nowadays i made my=20 own mixes, but now, i decided to go certified.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>My instructor, talking about thermal = loss in a=20 trimix class, explain me that the heat exchange is a=20 direct relationship with gas density.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>I=B4ve read and learn in the past = (including in=20 phisics class at regular school) that heat exchange depends of=20 thermal conductivity of the media (Q =3D mc delta t) where "c" = is the=20 thermal conductivity.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>Can you help me with that = ?</FONT></DIV> <DIV><FONT face=3DArial size=3D2>Am i right ?</FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>thanks </FONT></DIV> <DIV> </DIV> <DIV><FONT face=3DArial size=3D2>Marcelo=20 Moorea</FONT></DIV></BLOCKQUOTE></BODY></HTML> ------=_NextPart_000_0017_01C09B5F.7EA33F00-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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