Wilmot McCutchen

Could spherical deformation due to gravity pulling material to the center actually raise material near the surface with respect to material in the interior? Deep in the lithosphere, there is a zero displacement depth where the ratio k of horizontal stress to radial stress remains constant. Above this depth, k increases nonlinearly. Because of the free outer surface of the self-gravitating sphere, the material is able to expand in portions near the surface as compared with the material somewhat deeper. Could this be what uplifted the Colorado Plateau?

The counter-rotating centrifugal impellers of the open von Karman flow geometry provide surfaces for the molecules to bounce off and change direction. What happens to an individual molecule in the gas mixture would be difficult if not impossible to model, but bulk behavior of the ensemble of mixed molecules would be more predictable. Where the impellers come to close separation and high relative velocity (i.e. high shear rate) there is swirl forced in the gas mixture, and the vortices can't have a diameter greater than the impeller separation, even at the largest scale. It is this forced swirl of the bulk that provides the incentive for a particular molecule to change direction. Even if it does not bounce of an impeller, it will bounce off other molecules, and the high momentum molecules in the vortex shells absorb momentum from the low momentum molecules in the vortex cores, acting effectively as solid surfaces. With low momentum molecules continuously stripped out through the self-similar area-preserving vortex network in the shear layer between the impellers and axially exhausted, the remaining molecules of the bulk will have high momentum. Momentum diffusion from the high momentum molecules into the impellers will drive counter-rotation to force source flow of the bulk, and the steam ejector communicating with the axial exhaust conduit will force sink flow of the nitrogen ballast to axial extraction. The bulk will churn in the scrubber until eventually each molecule finds its exit. Looking from the point of view of an individual molecule, on entering the von Karman geometry it has two possible eventual exits: axial and peripheral. It may have a long residence time in the scrubber and a tortuous flow path, but eventually it will either go out the axial exhaust conduit at the axis of rotation of the impellers, or it will exit the space between the impellers at their periphery. Vortex separation by density is actually separation by momentum. The Vortex Tube thermal separation of gases is an example: high momentum gas molecules go out the hot end and low momentum molecules go out the cold end, without any forcing by moving parts. I believe this is called the Ranque effect. Maxwell's Demon (molecular separation without work) may be smart geometry where self-organized bulk separation of gases is able to manifest if the Reynolds number is high enough.

True. Thanks for your welcoming words. Let's assume that the area-preserving character of the self-similar vortex network means no pressure drop. The high gas velocity is not due to the impellers in the von Karman geometry, but to the intrinsic velocities of the molecules at thermal equilibrium. The necessary work for organizing the highly turbulent and high enthalpy flow can be compared to traffic enforcement by highways and traffic laws. Not nearly as much work as forcing the molecules, because you are just organizing the flow so the different momenta sort themselves into a radial spectrum, with steam at the center, then nitrogen, then CO2, then SO2. This spectrum is preserved in the zero pressure drop fractal vortex flow. In the case of turbine exhaust steam condensation, the expanding steam counter-rotates the organizing impellers and even harvests power. See http://www.freepatentsonline.com/7987677.pdf Radial Counterflow Steam Stripper US7987677B2.pdf

I did not mean to suggest that any methods that are presently used for uranium enrichment could be used for CO2 scrubbing. I don't understand how you came to the conclusion that my suggestion is "far worse than the existing methods used for CO2 scrubbing." Apparently you are under the impression that I was talking about narrow spinning cylinders, which is not the case. The existing methods for post-combustion CO2 capture you refer to are chemical capture by amine scrubbing, cryogenic separation, and membranes. Membranes are not feasible for flue gas, which comprises mercury vapor, water vapor, fly ash, and other aerosols that clog the pores. The work pushing utility-scale flow through the membrane is prohibitive. Cryogenic separation of hot dirty flue gas is not as good as air separation before combustion. Amine scrubbing will not work at utility scale because it will double water consumption of power plants. Also, heat stable salts are an unsolved problem. Air separation for oxyfuel combustion has the same 30% energy penalty as amine scrubbing, but it avoids the water consumption problem. Wouldn't a solution that uses the intrinsic momentum differences of flue gas fractions to self-separate them be superior to these conventional methods? If so, then why not think about it? Why must we only consider amine scrubbing for carbon capture?

I don't see an answer to Vay's question. He is an elementary physics student who needs the big picture. Vay asks a reasonable question: where does the 1/2 come from? He probably won't understand an explanation expressed with unfamiliar symbols and variables. Relativity theory is probably not familiar either. His question got me wondering, since there seems to be no ready answer. When we encounter classical mechanics as part of required coursework, time pressure leaves no leisure for such ruminations. Maybe others on this forum, who have more deeply considered this question, can provide a better answer than my ignorant speculation, but in good faith, here goes my conjecture: Momentum is always conserved, so you can add it moment to moment as the swarm of matter proceeds along a path. Summing an infinite quantity of infinitesimal momenta over a period of time and over a distance (in a definite direction, since we are considering kinetic energy rather than a diffuse form like heat) we integrate, to arrive at the expression for kinetic energy: 1/2* kg*m^2/s^2. Integration of momentum (kg*m/s) is what gives the 1/2 by the rules of calculus. So now I'm wondering, where did the 1/2 go in E = MC^2?

Sequestration in depleted oil reservoirs for enhanced oil recovery (EOR) can't be extrapolated to deep saline aquifers, which are full of brine. You'd have to get the brine out of there, and then where would it go? Not to the surface, surely, because we don't even have a solution for reverse osmosis reject brine yet, and this new ocean of 100,000 ppm brine will be a treatment nightmare. Where else, into the groundwater? Geological sequestration at utility scale has been condemned by petroleum engineering experts as "a profoundly non-feasible option for the management of CO2 emissions." http://twodoctors.org/manual/economides.pdf The available pore space has been overestimated. I agree with you that we seem to be stuck with coal for the time being.

The requisite millions of vortex structures would self-organize into an area-preserving fractal network, where vortices on many scales converge at the axis of rotation of counter-rotating centrifugal impellers. Pressure drop would be minimal because of the area-preserving character, where the cross-sectional areas of the eddies sum to the cross-sectional area of the axial exhaust conduit. The shear layer between the two boundary layers against the impellers is where the fractal network provides a sink flow path for nitrogen to axial extraction, assisted by a steam ejector. In addition to axial suction there is the backpressure radially in. The impellers preferentially advect the high molar mass constituents like CO2, SOx, mercury, radially outward as the nitrogen is advected radially inward through the vortex cores. So you see I was not talking about a cascade like the Dyson vacuum cleaner where there is a solid structure defining the vortex core, but a dynamic cascade. l am not sure if it would be appropriate to describe it as inverse Kolmogorov scaling -- the opposite of turbulent dissipation. Negative entropy through intelligent design.

If you were a Flatlander, the fourth dimension (height) would be ordinarily invisible, except as it leaves a footprint in Flatland. Flatlanders would know time, so the fourth dimension for them is height. Now take this a step further with existence in 3-D spacetime. The extra dimension would only be evident by its footprint in 3-D spacetime. Thanks to the recent advances in chaos theory and quarter-power scaling laws, now we can see such footprints.

At thermal equilibrium, all molecules in a gas mixture have the same kinetic energy, so the lighter molecules (low molar mass) must be going faster. The kinetic energy may be the same, but low molar mass molecules are on average faster, and have lower momentum. Consider a mixture of CO2 and nitrogen at thermal equilibrium at room temperature (300 K). The average speed (vrms) of the N2 molecules is 517 m/s and that of CO2 molecules is 412 m/s. The CO2 molecules have higher momentum than the N2 molecules. Consider now an eddy in that gas mixture and continuous axial flow out of that eddy. It is a coherent vortex like the Red Spot of Jupiter. The axial flow should be rich in low momentum molecules, i.e. nitrogen. Self separation of a gas mixture can occur spontaneously given the proper flow geometry. But without a way of collecting the separation effects to prevent remixing, nothing on a macroscopic scale will be noticed. Could the intrinsic momentum differences of the fractions in the gas mixture be exploited for mechanical gas separation in a way that does not depend on the conventional gas centrifuge of narrow cylinders rotating at high speed? For example, in a forced flow geometry comprising eddies having a 1mm radius, connecting to larger vortex structures in a tree network? In that 1mm eddy, the radial acceleration of the N2 is v^2/r or 27.2 million g. CO2 is only 17.3 million g. Area-preserving fractal networks, like the root system of trees, might provide a way to strip out the N2 through connected vortex cores so as to leave behind the CO2. See George Johnson's very interesting essay on quarter-power scaling and fractal networks. http://hep.ucsb.edu/courses/ph6b_99/0111299sci-scaling.html See also http://www.freepatentsonline.com/7901485.pdf

The difference between the near field and the far field is explained in this page on Wikipedia: http://en.wikipedia.org/wiki/Near_and_far_field

Maybe the question is about near field.

Please clarify "as the air comes out." Are you continuing to pump out the air? Stripping the dissolved noncondensible gases from the water and from the sealed unit will make the cavitation implosions stronger because the cushion of noncondensibles is gone. Shear, e.g. from shaking the sealed unit, will give a crackling sound.

Biogas comprises only ~70% methane. The rest is CO2 and water, which would have to be removed before putting it into a pipeline. California (the largest dairy state by far) has enacted a renewable energy standard that will require utilities to get 33% of their energy from "renewables." It would be great if the biogas could be made into pipelineable methane to get renewable energy credits that might make a dairy digester system profitable as well as politically correct.

Yes, radial intra-disk charge separation results from the Lorentz force acting oppositely on the positive and negative free charges that are already present. There would also be inter-disk charge separation across the space between the peripheries of the disks (due to the counter-rotation), so some charges from disk A might pass to disk B through that space once the setup becomes a dynamic capacitor.

Coaxial metal disks counter-rotating through an axial magnetic field would have opposite radial currents due to the Lorentz force. Therefore they would become oppositely charged. Although the voltage of Faraday disks is small, the current is large (they are used for rail guns and welding), so across the gap between the disks would be a high electric field. Since the disks are both spinning, incipient arc ends would be continuously pulled apart so power density would not erode the disks. Electrical and mechanical energy in large amounts could be coupled into the molecules between the disks by this dynamic capacitor. The electric field holds them, and the shear tears them apart.

The boosters of biogas don't have much to say about the difficulties of separating the methane from the CO2. Membranes and sorbents are the conventional prescriptions, but this is not necessarily a chemistry problem. Stovepiped science prevents the consideration of other approaches. CO2 has a molar mass (molecular weight) of 44 g/mol, water is 18 and CH4 is 16, so centrifugal gas separation in a high g device could separate the CO2 from the methane and water, and then condensation could separate out the water so the biogas could become suitable for pipeline delivery to power plants. Gravity settlement (1 g device) won't be enough. Conventional gas centrifuges (rapidly spinning narrow cylinders) won't work either. Radial counterflow gas separation might be the answer. The idea is that many tiny vortices perform high g separation, and a fractal vortex network collects the effects in a continuous process. For separating the solids from the water, to thicken the slurry until it is suitable for a digester, a high shear crossflow filter would be appropriate.