incredulity at the common calculation of freezing point depression.
"Rambling"?
Here the word "analysis" can apply. We "broke down the topic" of target site optimization, spending time on each aspect, for each candidate site. The integrated results improved our understanding, uniquely, and under NDA. That's one analysis.
Another example of analysis, with all results open: Dr. Lades analyzed the Mars Lift tether,
Quote from: meberbsYou put the strangest things under NDA. That sounds like something you should be publishing a scientific paper on if you had anything interesting to share. Prodding for NDA material is inappropriate, and repetitive prodding, more so. So stop.
You put the strangest things under NDA. That sounds like something you should be publishing a scientific paper on if you had anything interesting to share.
Quote from: meberbsYou started with the freezing point at -20 C rather than roughly 0 C for no apparent reason.Calcium chloride solution at 1.7 M freezes at -20 C. At 2.3 M, -40 C. So 0.6 M difference, as noted. The incredulous text was inappropriate, there and elsewhere.
You started with the freezing point at -20 C rather than roughly 0 C for no apparent reason.
Hard, yes. So much is hard at -60 C: i.e., a shower:A shower might use 40 liters at 42 C. [...]Whereas in the Lake Matthew scheme, the shower water is not heated, but cooled. Easier.
Quote from: LMT on 09/27/2017 02:59 amincredulity at the common calculation of freezing point depression.You started with the freezing point at -20 C rather than roughly 0 C for no apparent reason. You went on to predict around 5 times the actual freezing point change that would be expected from 0.6 M increase in concentration. If you want to recover some credibility, fixing your mistakes here would be a good place to start.
Hiding behind claims of trade secrets is inappropriate when discussing simple, well known (or easily guessable) physical phenomena.
For -40°C, you need more than 25% CaCl₂. That is not going to apply to a large body of water, so why mention it as if applying to any significant water reservoir?
I believe you've also failed to explain the discrepancy between claiming that the pressure in the under-lake open-floored dome is higher than the surrounding water, and therefore keeps the water out, while also claiming that the pressure in the dome is low enough to eliminate buoyancy.
keeping the salt in solution without it solidifying as CaCl₂·6H₂O is going to be difficult, especially if its open to evaporation which raises the salinity. That belies your claim that it "can persist with little active management".
Quote from: Paul451Hiding behind claims of trade secrets is inappropriate when discussing simple, well known (or easily guessable) physical phenomena.If someone claimed an invention that defied known physics, under NDA, you'd suspect "hiding". But where physical possibility is acknowledged, as with MATT, there's no such issue, obviously. You should remove any insinuation of "hiding".
Quote from: Paul451For -40°C, you need more than 25% CaCl₂. That is not going to apply to a large body of water, so why mention it as if applying to any significant water reservoir?Those numbers are in rough agreement with my note on brine freezing, yes?
Quote from: Paul451keeping the salt in solution without it solidifying as CaCl₂·6H₂O is going to be difficult, especially if its open to evaporation which raises the salinity. That belies your claim that it "can persist with little active management".Brines are easily managed on Earth, under evaporation.
And surely brine concentration can be applied to Omaha Crater reservoirs.
Dome perimeter air pressure must equal water pressure for moon pool formation. And I recall you had an incorrect understanding of buoyancy, which couldn't help. You might reexamine the actual F(bot) buoyancy force, to separate it clearly from the force due to air pressure.
Quote from: meberbs on 09/27/2017 07:48 amQuote from: LMT on 09/27/2017 02:59 amincredulity at the common calculation of freezing point depression.You started with the freezing point at -20 C rather than roughly 0 C for no apparent reason. You went on to predict around 5 times the actual freezing point change that would be expected from 0.6 M increase in concentration. If you want to recover some credibility, fixing your mistakes here would be a good place to start. That's the molarity change from -20 C to -40 C, also roughly corresponding with the chart for calcium chloride that paul451 posted. Where are you getting that "5 times" number?
Correction: With changing solvent mass the molarity change is more accurately ~ 1 M. So you're claiming 3x less change in freezing point.
Are you really claiming you don't know the difference between a genuine invention and an existing known physical phenomenon?Or do you deny that you initially refused to acknowledge that your plan used an asteroid impactor because it was proprietary? Do you still claim that the idea of using a redirected asteroid to create a crater is somehow proprietary knowledge?
Quote from: LMT on 09/28/2017 12:11 pmQuote from: Paul451For -40°C, you need more than 25% CaCl₂. That is not going to apply to a large body of water, so why mention it as if applying to any significant water reservoir?Those numbers are in rough agreement with my note on brine freezing, yes?Not as claimed by your molar numbers.
On Earth, brines are not operated near their eutectic points unless you are trying to precipitate out the target salt (such as the crystallisation stage of ZLD treatment, or, hell, any salt works.) They are either at relatively low salinity (5-10%) or are intentionally over the eutectic point in order to induce precipitation; they are not trying to maintain liquid solution in open pools near the eutectic point at sub-zero temperatures in the narrow window between freezing and solidifying.
Over 25% salinity by weight? In other words, around a fifth of the volume of the crater as one specific salt.
if you have a "moon pool", you certainly can't claim that the rim is somehow also sealed.
[Quote from: LMT on 09/28/2017 11:25 amCorrection: With changing solvent mass the molarity change is more accurately ~ 1 M. So you're claiming 3x less change in freezing point.Thank you for admitting this mistake. I had previously calculated as well that it is about 1 M to get from -20 to -40 C (post was lost in the thread reorganization)Quote from: LMT on 09/28/2017 12:11 pmQuote from: Paul451For -40°C, you need more than 25% CaCl₂. That is not going to apply to a large body of water, so why mention it as if applying to any significant water reservoir?Those numbers are in rough agreement with my note on brine freezing, yes?Or are you now trying to take back the admission of your mistake? 0.6M and 1M are not in "rough agreement"
Now that we established that your claims related to freezing point concentrations were inaccurate, maybe you can address some of the other issues you have been ignoring.
When you lead off with junk-psych like, "I hope you don't think that your last post had wowed everyone into acceptance," you're asking to be ignored. So it's a tone to drop, cold, moving forward.
Sounds like you would in fact have to heat the water first. By the way have you tried making an energy balance to figure out how much faster the crater will run out of heat with all of the ways you are using up energy?
Quote from: meberbs on 09/26/2017 02:41 pmSounds like you would in fact have to heat the water first. By the way have you tried making an energy balance to figure out how much faster the crater will run out of heat with all of the ways you are using up energy?Heat exchangers could be deployed on hotspots, in boreholes, or on the lakebed. They would heat water, yes, and with useful efficiency, as they require electricity only for the pump, and not for the heating itself. The giant habs would probably be the prime sites of heat loss. For dome heating, freshwater would be pumped through an exchanger and into the dome. A calc for a 300-m dome calls for a pump rated at ~ 7 kW, lifting 12 liters/s. Dome heat loss rate is roughly 2.3 MW, perhaps 18 hrs per sol. For a set of hab, greenhouse and industrial domes, daily heat loss would total 450 billion J. If the heat lens were devoted to heating just those giant domes, and had no other heat outlet, the bedrock would approach 0 C in about 6000 Earth years.Heat is lost slowly elsewhere of course, and 10^18 J is a conservative estimate of sensible heat in the heat lens, but that's the rough scale.Is that a surprising result, or about what you expected?
Quote from: Paul451 on 09/28/2017 02:31 pmAre you really claiming you don't know the difference between a genuine invention and an existing known physical phenomenon?Or do you deny that you initially refused to acknowledge that your plan used an asteroid impactor because it was proprietary? Do you still claim that the idea of using a redirected asteroid to create a crater is somehow proprietary knowledge?Well, you've shifted from the insinuation of "hiding" to a "Do you deny / Do you still claim [some strawman]" phrasing. Direct quote of the actual statement helps setup a question. Of course, if one has curiosity on NDA topics one can just ask for an NDA conversation.
In the Lake Matthew design, one quintillion Joules of sensible heat is liberated by proprietary means into bedrock at the site.
Quote from: strangequark on 04/11/2016 04:47 amThat's still the equivalent of a 240 megatons of TNT. Or about five Tsar Bomba nuclear weapons. If you're just going to handwave that away with "proprietary process", no one is going to take you seriously.Nuclear explosives are not used. The legal team knows the specifics, and has recommended the NDA on this point. But many other things can be discussed in open forum.
That's still the equivalent of a 240 megatons of TNT. Or about five Tsar Bomba nuclear weapons. If you're just going to handwave that away with "proprietary process", no one is going to take you seriously.
Quote from: Paul451 on 09/28/2017 02:31 pmAre you really claiming you don't know the difference between a genuine invention and an existing known physical phenomenon?Or do you deny that you initially refused to acknowledge that your plan used an asteroid impactor because it was proprietary? Do you still claim that the idea of using a redirected asteroid to create a crater is somehow proprietary knowledge?Well, you've shifted from the insinuation of "hiding"
to a "Do you deny / Do you still claim [some strawman]" phrasing.
Quote from: Paul451 on 09/28/2017 02:31 pmif you have a "moon pool", you certainly can't claim that the rim is somehow also sealed.? I think you've mixed in someone else's idea there. Moon pools don't need a seal; they're open to the air, by definition.
[I want] a summary that shows crater remaining heat and temperature vs. time, a breakdown of the different mechanisms of heat loss, and consumption. (ground conduction, atmospheric and evaporation, energy generation, base heating, melting and warming additional water, etc.) Efficiency, rates and such would change with time, since they would depend on the current crater temperature.
Quote from: LMTThawing or fracturing of the cryosphere base would admit a hypothetical closed aquifer into the crater bedrock and potentially the surface water bodies. The existence of a closed aquifer is unknown, but given the widespread regional evidence of ice, a closed aquifer should be considered.Here are more examples of you listing various ways things could go well if you get lucky. A serious analysis would consider whether or not the plan is viable if none of these bonus things happen. Bringing them up before all of the ways things can go wrong are addressed is a waste of time.
Thawing or fracturing of the cryosphere base would admit a hypothetical closed aquifer into the crater bedrock and potentially the surface water bodies. The existence of a closed aquifer is unknown, but given the widespread regional evidence of ice, a closed aquifer should be considered.
If there's a moon-pool, the dome is connected to the outside lake that's around and above the dome. The dome will therefore experience buoyancy equal to its displacement of water. That's how buoyancy works. (By mentioning a sealed rim, I was eliminating the only possible way of avoiding buoyancy, a partial vacuum under the dome with a water-tight seal around the dome. I could have also pointed out that with broken bedrock of an impact crater, that also means you can't have a water-tight seal.)
you have a pattern of hiding behind false claims of trade secrets
Quote from: meberbs on 09/29/2017 05:59 am[I want] a summary that shows crater remaining heat and temperature vs. time, a breakdown of the different mechanisms of heat loss, and consumption. (ground conduction, atmospheric and evaporation, energy generation, base heating, melting and warming additional water, etc.) Efficiency, rates and such would change with time, since they would depend on the current crater temperature.That's quite the grab-bag of wants. But no, the mentioned references give what's needed at this time. Omaha Crater, at ~9 km, would have properties in the scope of the following modeled craters, from the list of useful papers previous:
Quote from: meberbs on 09/26/2017 02:41 pmQuote from: LMTThawing or fracturing of the cryosphere base would admit a hypothetical closed aquifer into the crater bedrock and potentially the surface water bodies. The existence of a closed aquifer is unknown, but given the widespread regional evidence of ice, a closed aquifer should be considered.Here are more examples of you listing various ways things could go well if you get lucky. A serious analysis would consider whether or not the plan is viable if none of these bonus things happen. Bringing them up before all of the ways things can go wrong are addressed is a waste of time.No, that reading doesn't make sense. Meltwater throughout the heat lens is the expected, unavoidable first water source, and a valid reason for confidence. Aquifer beneath the cryosphere is neither assumed nor needed for viability; it's just a further possibility. You should have acknowledged the unavoidable first water source.
Quote from: Paul451 on 10/02/2017 09:32 amyou have a pattern of hiding behind false claims of trade secretsNo.
Now I'll ask one last time, because you still haven't finished your statement: did you also get a 1 M delta on that CaCl2 brine?
Quote from: Paul451 on 10/02/2017 09:32 amIf there's a moon-pool, the dome is connected to the outside lake that's around and above the dome. The dome will therefore experience buoyancy equal to its displacement of water. That's how buoyancy works. (By mentioning a sealed rim, I was eliminating the only possible way of avoiding buoyancy, a partial vacuum under the dome with a water-tight seal around the dome. I could have also pointed out that with broken bedrock of an impact crater, that also means you can't have a water-tight seal.)Instead of re-arguing buoyancy, and re-ignoring the physical meaning of F(bot)
Your sketch and force calculations should make the mistake evident.
You should consider making a complete diagram of your installation. Right now we can piece it together by reading the hints you spread in your posts, but that's tedious and few people will do it. And I imagine if you didn't want people to have an idea of the whole thing, you would not be talking about it.
In the Lake Matthew design, one quintillion Joules of sensible heat is liberated by proprietary means into bedrock at the site. [...]We don’t mean to tease, but there are trade secrets at work here. Everyone is free to speculate, and we can talk about things that aren’t secret [...] but some things can only be discussed under NDA.
wrt the notional "Lake Matthew": It's our unobvious, proprietary methods that liberate 1018 Joules of sensible heat in bedrock, whereby Lake Matthew becomes possible.
Speaking both for myself and for the whole Lake Matthew Team...