Comments on: Saul Griffiths' sun-tracking solar systems and intestine-inspired car gas tanks http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html Brain candy for Happy Mutants Mon, 20 May 2013 01:33:00 +0000 hourly 1 http://wordpress.org/?v=3.4.1 By: Brainspore http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641891 Brainspore Thu, 31 Jan 2013 00:00:00 +0000 http://boingboing.net/?p=209676#comment-1641891 That's nothing compared to what would happen with a tank full of Mission burritos. That’s nothing compared to what would happen with a tank full of Mission burritos.

]]> By: Antinous / Moderator http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641861 Antinous / Moderator Wed, 30 Jan 2013 23:34:00 +0000 http://boingboing.net/?p=209676#comment-1641861 If you live in SF and drive accordingly, I'm pretty sure that your catalytic converter is already pushing out sulfur farts. If you live in SF and drive accordingly, I’m pretty sure that your catalytic converter is already pushing out sulfur farts.

]]> By: seanmchugh http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641827 seanmchugh Wed, 30 Jan 2013 23:06:00 +0000 http://boingboing.net/?p=209676#comment-1641827 Got it.  Thanks! Got it.  Thanks!

]]> By: dioptase http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641817 dioptase Wed, 30 Jan 2013 22:59:00 +0000 http://boingboing.net/?p=209676#comment-1641817 The thickness increases proportional to diameter and area increases proportional to diameter. Weight increases with the square of the increase of diameter. hoop stress = pressure*radius/thickness So for a constant stress and pressure, the ratio of diameter to thickness is a constant. reference: http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/pressure_vessel.cfm The thickness increases proportional to diameter and area increases proportional to diameter. Weight increases with the square of the increase of diameter.

hoop stress = pressure*radius/thickness

So for a constant stress and pressure, the ratio of diameter to thickness is a constant.

reference: http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/pressure_vessel.cfm

]]> By: Ladyfingers http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641810 Ladyfingers Wed, 30 Jan 2013 22:55:00 +0000 http://boingboing.net/?p=209676#comment-1641810  My first thought was "that looks a bit too close to the boundaries of the vehicle."  My first thought was “that looks a bit too close to the boundaries of the vehicle.”

]]> By: seanmchugh http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641783 seanmchugh Wed, 30 Jan 2013 22:33:00 +0000 http://boingboing.net/?p=209676#comment-1641783 The wall thickness is chosen to accommodate a particular pressure.  Assuming the pressure stays the same, then wall thickness is independent of diameter. So if one wants to accommodate the same volume of gas, the weight of the container increases proportional to the increase in surface area.  Am I missing something? The wall thickness is chosen to accommodate a particular pressure.  Assuming the pressure stays the same, then wall thickness is independent of diameter. So if one wants to accommodate the same volume of gas, the weight of the container increases proportional to the increase in surface area.  Am I missing something?

]]> By: Colby Gutierrez-Kraybill http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641784 Colby Gutierrez-Kraybill Wed, 30 Jan 2013 22:33:00 +0000 http://boingboing.net/?p=209676#comment-1641784 Also, methane contributes 75 times more per unit of straight up CO2 added to the atmosphere over a 20 year time-horizon.  That may make the broad use of natural gas a wash unless you can leak 75 times less per unit CO2 into the atmosphere. Also, methane contributes 75 times more per unit of straight up CO2 added to the atmosphere over a 20 year time-horizon.  That may make the broad use of natural gas a wash unless you can leak 75 times less per unit CO2 into the atmosphere.

]]> By: unclegabby http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641759 unclegabby Wed, 30 Jan 2013 22:10:00 +0000 http://boingboing.net/?p=209676#comment-1641759 That makes the tank much more expensive to make, customized for each vehicle, and exposes it more crash zones. That makes the tank much more expensive to make, customized for each vehicle, and exposes it more crash zones.

]]> By: Brainspore http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641737 Brainspore Wed, 30 Jan 2013 22:00:00 +0000 http://boingboing.net/?p=209676#comment-1641737 That's a good point, if anything the stomach is a better analog to a gas tank than the intestines. That’s a good point, if anything the stomach is a better analog to a gas tank than the intestines.

]]> By: BannedinDC http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641734 BannedinDC Wed, 30 Jan 2013 21:56:00 +0000 http://boingboing.net/?p=209676#comment-1641734 He's also off a ton on US oil imports.  Imports are only 8m barrels per day and have been dropping since 2000 (from a high of 11m).  You can blame/thank US shale oil production for that. source: http://www.eia.gov/dnav/pet/pet_move_impcus_a1_Z00_epc0_im0_mbblpd_m.htm He’s also off a ton on US oil imports.  Imports are only 8m barrels per day and have been dropping since 2000 (from a high of 11m).  You can blame/thank US shale oil production for that.

source: http://www.eia.gov/dnav/pet/pet_move_impcus_a1_Z00_epc0_im0_mbblpd_m.htm

]]> By: peterkvt80 http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641722 peterkvt80 Wed, 30 Jan 2013 21:46:00 +0000 http://boingboing.net/?p=209676#comment-1641722 Why are gas tanks cylindrical? It equalizes the stresses and minimizes surface area. So you need less material to make a stronger tank. Why are intestines the shape that they are? Partly to maximize surface area to absorb nutrients so more material required. The novel tank is going to be much heavier. Why are gas tanks cylindrical? It equalizes the stresses and minimizes surface area. So you need less material to make a stronger tank. Why are intestines the shape that they are? Partly to maximize surface area to absorb nutrients so more material required. The novel tank is going to be much heavier.

]]> By: dioptase http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641716 dioptase Wed, 30 Jan 2013 21:43:00 +0000 http://boingboing.net/?p=209676#comment-1641716 For high pressure cylinders, 1/2 the diameter will mean you only need 1/2 the wall thickness.  1/2 the wall thickness and 1/2 the diameter means 1/4 the weight.  But 1/2 the diameter also means 1/4 the volume.  So at first blush, it's a wash.  But you've now got twice the surface area to volume ratio, increasing potential failure points.  And you have half the capacity to tolerate damage. For instance, 1mm of damage on a 10 mm wall is far less trouble than 1mm of damage on a 1 mm wall. As for the heliostat proposal, there's not enough information to evaluate it properly.  If all you go by is the use of plastic and the picture, it appears one good storm and you can kiss your solar farm goodbye. For high pressure cylinders, 1/2 the diameter will mean you only need 1/2 the wall thickness.  1/2 the wall thickness and 1/2 the diameter means 1/4 the weight.  But 1/2 the diameter also means 1/4 the volume.  So at first blush, it’s a wash.  But you’ve now got twice the surface area to volume ratio, increasing potential failure points.  And you have half the capacity to tolerate damage.

For instance, 1mm of damage on a 10 mm wall is far less trouble than 1mm of damage on a 1 mm wall.

As for the heliostat proposal, there’s not enough information to evaluate it properly.  If all you go by is the use of plastic and the picture, it appears one good storm and you can kiss your solar farm goodbye.

]]> By: Brainspore http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641708 Brainspore Wed, 30 Jan 2013 21:39:00 +0000 http://boingboing.net/?p=209676#comment-1641708 Intestine-inspired car gas tanks? Not looking forward to those, ah, "emissions…" Intestine-inspired car gas tanks? Not looking forward to those, ah, “emissions…”

]]> By: Dave Jenkins http://boingboing.net/2013/01/30/saul-griffiths-intestine-ins.html#comment-1641681 Dave Jenkins Wed, 30 Jan 2013 21:16:00 +0000 http://boingboing.net/?p=209676#comment-1641681 The laws of thermodynamics and Boyle might have a problem with this scheme.  The DOT would _definitely_ have a problem with this idea. The laws of thermodynamics and Boyle might have a problem with this scheme.  The DOT would _definitely_ have a problem with this idea.

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