light reflection from gels [Archive]

alistair

Apr14-04, 03:17 AM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Some gels when compressed reflect a shorter wavelength of light than\nwhen they are uncompressed because their constituent particles get\ncloser together and form a kind of 3D grating.But it is difficult to\nmake these gels uniform because of gravity, so gels are currently\nbeing developed in space.But can anyone think of a way of overcoming\nthe gravity problem in a lab here on Earth?\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>Some gels when compressed reflect a shorter wavelength of light than
when they are uncompressed because their constituent particles get
closer together and form a kind of 3D grating.But it is difficult to
make these gels uniform because of gravity, so gels are currently
being developed in space.But can anyone think of a way of overcoming
the gravity problem in a lab here on Earth?

Doug Goncz

Apr15-04, 11:28 AM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>>From: alistair@goforit64.fsnet.co.uk (alistair)\n\n>it is difficult to\n>make these gels uniform because of gravity, so gels are currently\n>being developed in space.But can anyone think of a way of overcoming\n>the gravity problem in a lab here on Earth?\n\nIsn\'t there a combo with components of differing optical densities but\nidentical gravimetric densities? Such a gel would form on Earth as in space.\n\n\nYours,\n\nDoug Goncz ( ftp://users.aol.com/DGoncz/ )\n\nMy physics project at NVCC:\nhttp://groups.google.com/groups?q=dgoncz&scoring=d plus\n"bicycle", "fluorescent", "inverter", "flywheel", "ultracapacitor", etc.\nin the search box\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>>From: alistair@goforit64.fsnet.co.uk (alistair)

>it is difficult to
>make these gels uniform because of gravity, so gels are currently
>being developed in space.But can anyone think of a way of overcoming
>the gravity problem in a lab here on Earth?

Isn't there a combo with components of differing optical densities but
identical gravimetric densities? Such a gel would form on Earth as in space.

Yours,

Doug Goncz ( ftp://users.aol.com/DGoncz/ )

My physics project at NVCC:
http://groups.google.com/groups?q=dgoncz&scoring=d plus
"bicycle", "fluorescent", "inverter", "flywheel", "ultracapacitor", etc.
in the search box

Pieter Kuiper

Apr16-04, 02:28 AM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>alistair@goforit64.fsnet.co.uk (alistair) wrote:\n\n> It is difficult to\n> make these gels uniform because of gravity, so gels are currently\n> being developed in space. But can anyone think of a way of overcoming\n> the gravity problem in a lab here on Earth?\n\nOne can float diamagnetic things in a magnetic field:\n<http://www.hfml.sci.kun.nl/froglev.html>.\n\n--\n"Electrons damage the brain," said Farish. (Donna Tartt)\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>alistair@goforit64.fsnet.co.uk (alistair) wrote:

> It is difficult to
> make these gels uniform because of gravity, so gels are currently
> being developed in space. But can anyone think of a way of overcoming
> the gravity problem in a lab here on Earth?

One can float diamagnetic things in a magnetic field:
<http://www.hfml.sci.kun.nl/froglev.html>.

--
"Electrons damage the brain," said Farish. (Donna Tartt)

alistair

Apr16-04, 02:28 AM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Rotating the gel after a set time period would help minimise\ngravitational bias\nbut the act of rotation could itself cause particles suspended in the\ngel to move preferentially in one direction.Perhaps a steady electric\nfield which is applied for equal intervals of time along the x,y and z\naxes might be better.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>Rotating the gel after a set time period would help minimise
gravitational bias
but the act of rotation could itself cause particles suspended in the
gel to move preferentially in one direction.Perhaps a steady electric
field which is applied for equal intervals of time along the x,y and z
axes might be better.