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Comment: Reading between the lines (Score 5, Informative) 256

by Michael Woodhams (#46702421) Attached to: Navy Creates Fuel From Seawater

TFA was points to a 2012 press release, but it contains not much more information. They must need to supply energy to this reaction, but whether this energy is as heat, electricity or something else is unclear.

I see two uses from the point of view of the U.S. navy. One is to put one of these chemical plants in an aircraft carrier, power it with the carrier's reactor, and generate fuel for the aircraft on board. The other is to put the chemical plant on a nuclear powered supply ship, which will then transfer the fuel to non-nuclear surface ships.

From a world energy point of view, this is a way to turn non-fossil fuel power (nuclear, hydro, wind) into hydrocarbon fuel, with the overall process being carbon neutral. Burning fossil fuels to provide the energy for this process would certainly be counter productive in terms of CO2 emission and very likely economically counter productive as you'd be better chemically processing your fossil fuel instead.

By the time you're going to all of this trouble to turn electricity into fuel, it is unlikely that you'd want to run a car on it - you'd rather just have an electric car. For aircraft we really have no good alternative to hydrocarbon fuels, so it could be used here. However, on the road to a low-carbon future, we have decades worth of lower hanging fruit (notably coal power stations) before we really need to care about whether our aircraft fuels are carbon neutral.

Conspicuously missing from the articles is the energy efficiency of this process. Given the $3-$6 per gallon projected jet fuel cost, presumably the efficiency is not too bad. (I notice this number hasn't changed since 2012 which makes me suspicious that it is more guesswork than calculation.)

Comment: War Secrets in the Ether (Score 2) 102

by Michael Woodhams (#46644239) Attached to: Book Review: How I Discovered World War II's Greatest Spy

If you're interested in the German side of world war cryptanalysis, an excellent book is War Secrets in the Ether, by Wilhelm Flicke. The author was a German cryptanalyst during the two world wars, and it was written shortly after the end of the second world war. (It is out of print, so I suggest looking in libraries.)

It has been a decade or more since I read it, so I may have misremembered details, but here are a few points of note:

Pre-war, he'd been analysing Russian radio usage. They had a complicated system where the same station would use different call signs depending who they were talking to. This made their intercepts more chaotic and harder to do traffic analysis on. He and all his colleagues were shifted to the western front with the outbreak of war. When the war with Russia started, in the initial shock their complicated system failed and they fell back on a more standard system. Once they started to get over the initial attack and reorganize, they returned to the complicated system. The German cryptanalysts who were present had no experience with this (the experienced ones having been moved) so they interpreted the chaoticness of the signals as showing the Russians were in complete disarray, when the exact opposite was true.

He thought that the course of Battle of Crete indicated that the allies had broken the German codes at that time. (Which was correct, but he missed that they'd broken most of the German codes for almost the entire war.)

They knew that the allies had very good intelligence, but thought that it was supplied by spies. As a result, he spend the second half of the war on a whack-a-mole mission to shut down spy radio transmitters.

He complained about the multitude of German intelligence agencies and their lack of cooperation due to infighting.

Comment: Just sit back and enjoy the show (Score 4, Interesting) 133

by Michael Woodhams (#46600141) Attached to: Kim Dotcom Launches Political Party In New Zealand

I really enjoyed this commentary. An extract:

"Eighteen months ago, after the slap-stick bumbling and embarrassing forelock pulling by New Zealand authorities to their United States counterparts was revealed, I was moved to wonder if Dotcom was in fact a computer virus, slowly infecting our senior politicians and agencies of state, and transforming them into figures of fun.

Whether he is a virus, or a puckish imp, sent by the gods to mock those who would rule over us, Dotcom continues his uncanny facility to bring out the ridiculous in them."

Wherever you stand on his legal issues, business ventures and politics, he is great entertainment.

Comment: Re:Bad news for ecologists--new license needed (Score 2) 136

by Michael Woodhams (#46340867) Attached to: Major Scientific Journal Publisher Requires Public Access To Data

There are plenty of scientists out there who poach free online data sets and mine them for additional findings.

And this is a good thing, despite your word "poach". Analyses which would not have occurred to the original experimenters get done, and we get more science for our money. For many big data projects (e.g. the human genome project, astronomical sky surveys), giving 'poaching' opportunities is the primary purpose of the project.

A former boss of mine once, when reviewing a paper, sent a response which was something like this:

"This paper should absolutely be published. The analysis is completely wrong, but it is a wonderful data set, and somebody will quickly publish a correct analysis once the data is available."

Now I need to stop wasting time on /. and return to my work in hand, which, as it happens, is 'poaching' data from
Ingman, M., H. Kaessmann, S. Paabo, and U. Gyllenstern. 2000.
Mitochondrial genome variation and the origin of modern humans. Nature 408:708--713.

Comment: Re:"Back to the launch site"? (Score 1) 73

by Michael Woodhams (#46331395) Attached to: SpaceX Testing Landing Legs On Next Falcon9 Rocket

OK, so I'm officially amazed.

Fuel is cheap when it is sitting in a tank on the ground. Fuel at 100 km altitude and 5km/s speed is a very different story. Fuel which you keep in stage I for 'boost back' is fuel you aren't using to put your payload into orbit, meaning you have lower maximum payload.

Comment: Re:"Back to the launch site"? (Score 1) 73

by Michael Woodhams (#46330887) Attached to: SpaceX Testing Landing Legs On Next Falcon9 Rocket

A parachute doesn't solve the problem of your stage being hundreds of km downrange from the launch site. A parachute can help in any of my three proposed scenarios. (I think you'd need to jettison the parachute and drop for a bit before firing the rockets, because I don't think you want to try to land while attached to or entangled in a chute. This is what Curiosity did on Mars.)

Comment: "Back to the launch site"? (Score 1) 73

by Michael Woodhams (#46329795) Attached to: SpaceX Testing Landing Legs On Next Falcon9 Rocket

How does this work? The rocket will have gone far down range before the first stage separates.

* First stage reverses direction and comes back. Very fuel expensive, I'd be amazed if they're planning this.
* First stage does one 'orbit' (technically it would still be 'sub-orbital') and returns to launch site from opposite direction. Requires that the stage has sufficient energy, and requires some cross-range maneuvering unless you launch from the equator.
* Summary is incorrect, and stage landing site is not the launch site.

In any case, you really want your landing site to be in the middle of nowhere because some failure modes will result in a high energy impact.

User Journal

Journal: In principio erat Verbum.

Journal by Michael Woodhams


In the beginning was the word. Biblical, John 1:1. The full verse is
"In principio erat Verbum et Verbum erat apud Deum et Deus erat Verbum. "
"In the beginning was the Word, and the Word was with God, and the Word was God."

Comment: Re:David Weber (Score 1) 236

by Michael Woodhams (#46271447) Attached to: I'd prefer military fiction books that are ...

I tried a couple of Honor Harringtons but gave up in disgust at the author's political strawmanning.

In those books, a character can't be pacifist without also being cowardly, hypocritical, corrupt and Machiavellian. Only characters who adhere to a particular militaristic mindset can be good people. Although they were otherwise mostly good, this aspect killed my enjoyment.

Also, one chapter started with a short paragraph which managed to gratuitously specify about eight statistics on some (real current world) handgun. I think it was the worst paragraph I've ever read in professional fiction.

Simplicity does not precede complexity, but follows it.