Domain: llnl.gov
Stories and comments across the archive that link to llnl.gov.
Comments · 548
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Re:this is why i laugh at hydrogen cars
Hydrogen has the potential for a much higher energy density than batteries (new battery tech might change that, but hasn't so far.) "The regenerative fuel cell, coupled with lightweight hydrogen storage, had by far the highest energy density--about 450 watt-hours per kilogram--ten times that of lead-acid batteries and more than twice that forecast for any chemical batteries." So you waste solar energy charging the things (land area used), but gain a better battery. They can also be much faster to charge, since you simply need to add hydrogen and oxygen to the storage tanks, instead of waiting several hours for an electric current to charge a battery.
Hydrogen fuel cells aren't really about using less energy, they're about being a practical alternative to gasoline. Battery tech isn't there yet, fuel cells aren't either but may become practical sooner. Wasted solar energy does not impose extra costs in the same way as wasted fossil fuel energy. -
Re:Yes but Octave
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Re:bad journalism
The hope is that by understanding ignition other nuclear fusion projects will be able to make better progress..
And by 'other fusion projects' they mean H-bombs.
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Re:bad journalism
From https://lasers.llnl.gov/about/nif/
The resulting fusion reaction will release many times more energy than the laser energy required to initiate the reaction. Experiments conducted on NIF will make significant contributions to national and global security, could lead to practical fusion energy, and will help the nation maintain its leadership in basic science and technology.
The goal of this kind of experience is geared toward energy production. Granted, this is not a prototype power plant, but one could consider the lasers used there as a prototype for elements of a power plant."
To sharpen this point a bit, the NIF is a physics experiment to study the behavior of a particular class of inertial confinement fusion targets - indirect drive pellet explosions. There are other approaches (direct drive fast ignition) that may be more promising.
The lasers used for the NIF are entirely useless as a model for future power production. It is a technological dead end similar to using rubber band sling shots to study flight.Your sling shot can launch a glider allowing you to realistically study airfoil behavior and stability (subject to appropriate scaling laws), but there is no way a super-duper high tech sling shot is giving you useful air transportation. The most promising driver technology - heavy ion particle beams - is not being actively pursued in the U.S.
An interesting aspect of the particular target technology being studied at LLNL is that it is very closely related to thermonuclear weapon designs, so closely in fact that until 1997 almost every aspect of this research required nuclear weapons clearances to study in the U.S. The code used to model ICF implosions at NIF is a classified code (very unusual for basic science) derived from nuclear weapons design codes. And the NIF is scheduled to do classified experiments of an unspecified kind, along with its basic science.
By the way. LLNL is not only a national lab, it is a nuclear weapons lab. Might the relative lack of interest in aspects of the ICF problem that are essential for commercialization, and the emphasis on technical approaches that are most closely allied to nuclear weapons technology, suggest that LLNL is more interest in studying tiny model swords, instead of plowshares?
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It's not a power program
The Livermore laser fusion work has very little to do with power production. Laser fusion has been talked up for 40 years. It turned out that it was really a cover for nuclear weapons R&D. If the physicists can't set off H-bombs, the big laser projects let them do pulsed fusion and gather data. It's now considered part of the "stockpile stewardship" program, or what's sometimes called the Livermore Senior Activity Center for Physicists.
This is a pulsed system. It's not an attempt to produce a sustained thermonuclear reaction, which is what's needed for power production. It's purely a research device which pumps a large amount of power into a small space to achieve a moment of fusion. That's purely an experimental tool.
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Re:bad journalism
Indeed, it's not like they've posted information on the fact that they intend to model nuclear weapons in plain sight on the internet as one of their three missions.
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Re:bad journalism
The research they're doing will not have applications in energy production.
Yes it will. However, it is worth mentioning that this is only one of its three missions, and most likely the main reason that this massive multi-billion dollar project received funding from Congress was so that we could we can understand fusion reactions well enough that we can model the inside of nuclear weapons and not have to test them, seeing as how we don't like testing nuclear weapons anymore.
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Re:bad journalism
The research they're doing will not have applications in energy production.
Yes it will. However, it is worth mentioning that this is only one of its three missions, and most likely the main reason that this massive multi-billion dollar project received funding from Congress was so that we could we can understand fusion reactions well enough that we can model the inside of nuclear weapons and not have to test them, seeing as how we don't like testing nuclear weapons anymore.
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Re:bad journalismFrom https://lasers.llnl.gov/about/nif/
The resulting fusion reaction will release many times more energy than the laser energy required to initiate the reaction.
Experiments conducted on NIF will make significant contributions to national and global security, could lead to practical fusion energy, and will help the nation maintain its leadership in basic science and technology.The goal of this kind of experience is geared toward energy production. Granted, this is not a prototype power plant, but one could consider the lasers used there as a prototype for elements of a power plant.
The summary also is funny in how it understates achievements of fusion research. I remember a physicist saying "The Sun ? Pfah ! Too cold and too inefficient ! If we were to reproduce the conditionss in the sun, we would never get anything that would interest industries !" -
Re:Good move...
there is zero chance you'll be able to come up with a convincing case for one oil rig being less dangerous to workers than any practical size of wind farm
The grandparent post is definitely talking out his ass, but it's an interesting question, so I ran the numbers myself.
No question more people die mining coal than running wind power, but since coal is a much bigger industry, I think the fairest comparison is number of accidental deaths per unit electricity produced.
US coal mine deaths, 2005-2009: 30/year
http://www.msha.gov/stats/charts/coal2009yearend.asp
US coal energy produced, 2008: 22.4 quads (or exajoules)
Heat -> Electricity efficiency factor: 30%https://publicaffairs.llnl.gov/news/energy/energy.html
US energy from coal: 6.7 exajoules/year
Worldwide wind power deaths, 2000-2006: At least 15, avg 2.7/year
http://www.windaction.org/documents/1318Worldwide wind power installed capacity, avg 2001-2006: 40,000 MW
http://www.wwindea.org/home/index.phpAverage capacity factor for wind plants: 25%
Estimated world wind energy output, 2001-2006 avg: 0.32 exajoules/year
Bottom line:
US Coal mining deaths per exajoule electricity produced: 4.5
World wind power deaths per exajoule electricity produced: at least 8.4Surprised? I sure was! I expect the wind power number to drop dramatically as the industry develops, of course.
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Re:North American Grid
Lots of working models. Even some you can build.
The problem is that everyone focused on hydrogen because they sorted that energy density page by mass, not by volume. It's a very poor fuel. People are too focused on hydrogen IMHO. The best and cheapest methods so far considered to store hydrogen (reacting water with metal) all lead to the conclusion that metals are better. The fact that people have made metal air cells in their house that actually power things also shows that they are better.
Metal-air batteries work, and so does electrolysis to regenerate the batteries. The problem most of the companies I've seen so far hit has been the process of pumping the solid fuels ("pumping iron"). I'm a highschool student, so don't take my word for it. I'm also a roboticist, and so I think that if I can get the chemistry working, I can build robots to deal with fuel handling. -
Re:The problem??
Yes burnt and burning are terms wildly used in the nuclear industry and in science.
Sort of like this place https://lasers.llnl.gov/ is called the National Ignition Facility.
So not it is not dumbing down science it is showing the flexibiltiy in the language. Sort of like how a satellite and or rocket is often called a bird. They sure are not avian but it is a common term. -
Re:For our sake
Not only is your link to an article about the "debate" NOT about the recent debate, which was still occurring mere months ago...
You didn't cite any papers, so I had to guess what you were talking about. If you could show me some papers regarding this other debate that happened mere months ago, maybe this would be a more productive conversation.
the article actually supports the assertion I was making, and is nowhere near a "solution" to the problem to which I was referring.
... the article specifically mentions that "The newest satellite dataset correction doesn't reconcile differences between climate trends in the lower layer of the atmosphere..." which was one of the obvious problems with the models to which I referred. ... it states that the tropospheric warming observed would need to be 2.6 times greater than what was observed in order to support what the climate models predicted. ... You just linked to an article that clearly and unequivocally stated it was fundamentally flawed as recently as 2005... off in a major way by a factor of 260%. That's not a "tweak", that's a fundamental flaw.Upon re-reading the press release, I didn't see a factor of 2.6 anywhere. They do mention a 26 year data span, but here's the most relevant quote I can find: "As a general rule, the climate models predict that the tropical troposphere should be warming 1.3 times faster than whatever the surface is doing. And it is only in the tropics that the surface and the troposphere don't seem to follow what the models forecast."
I only linked that press release in an attempt to see if this debate is what you were talking about. Since it's apparently not, I should really just wait for you to link the journal papers that are central to this other debate.
But just in case you're interested, this particular debate began with a 2004 paper by Douglass, Pearson and Singer. As usual, the first step in evaluating any scientific debate is to follow the citations in (for example) google scholar. Notice that a more recent paper (PDF) says: "Our results contradict a recent claim that all simulated temperature trends in the tropical troposphere and in tropical lapse rates are inconsistent with observations. This claim was based on use of older radiosonde and satellite datasets, and on two methodological errors: the neglect of observational trend uncertainties introduced by interannual climate variability, and application of an inappropriate statistical consistency test. "
There are useful lessons to be drawn from this debate. For instance, they suggest (along with other lines of evidence) that GCMs can't yet fully account for ENSO and other inter-annual oscillations, need improved moist convection and cloud parameterizations, etc. I caution people not to make regional climate predictions for precisely this reason: the GCMs aren't yet sophisticated enough. Global averages, however, are considerably more reliable and robust for the same reason that opinion polls with larger sample sizes have smaller error bars.
I understand your statement that "they settled on more robust model evaluation techniques", but if so then they did so remarkably quickly, since this debate was still going on mere months ago, until troposphere warming data was updated to show observations that it was in fact warming as it should have been according to the models.
If you really did under
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Decline
If only the US had launched some space observatories
If only the US had bothered to maintain some of its science assets
If only the US had conducted any exploration of our solar system
If only the US had commissioned any meaningful physics experiments
If only the US had any anthropologists discovering stuff
If only the US had any geneticists discovering stuff
If only the US had bothered to conduct any nuclear physics experiments
If only the US had any medical science to speak of
If only the US had any practicing bioengineers
If only the US had funded any studies into the harmful effects of BPA...then maybe then SlashSnot editors would avoid indulging their myopic views of the US science.
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Re:Could the NIF be scaled to a fusion process?NIF is the first generation. Sort of a proof of concept for the next one. I was fortunate enough to tour it on family day last May. Very impressive to see. https://lasers.llnl.gov/about/missions/energy_for_the_future/life/
qz
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Re:We're getting closer
The Lawrence Livermore National Laboratory have been compiling a comprehensive review of energy usage in the USA for many years now. They make a cool energy flow diagram that shows where all the energy in the US comes from and goes to. You can find it at https://publicaffairs.llnl.gov/news/energy/energy.html In 2008, about 27% of energy from electricity generation was "rejected". I think that this is mostly transmission loss. It's a very informative diagram, simultaneously interesting and depressing
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It's hard, but not that hard
There are engineering details to building a nuclear weapon that aren't well known. But they're not all that deeply hidden, either. A few minutes with Google gets you the basics.
A big, dumb Hiroshima-type implosion bomb made of uranium isn't that hard. Plutonium bombs are tougher to build; more compression is necessary. The later designs have reflectors, tampers, and quite a few layers. Considerable simulation is required to get the design right. Of course, the US and the USSR designed their nuclear arsenals with computers in the 1 MIPS range; today, any laptop has enough CPU power for bomb design. Some older hydrodynamic software for this is available, in FORTRAN. Note the test cases provided, "Detonation example" and "SSTAFF warhead".
A more modern version of that software is available from LLNL. The code was released in 1996 and was upgraded through 2005. There's a torrent available.
Making the components is a pain because many of the materials involved are radioactive, poisonous, flammable metals, or high explosives. Machining uranium is difficult. However, there's a convenient how-to guide, "Machining of Uranium and Uranium Alloys", written by a head machinist at the Oak Ridge Y-12 plant and distributed by the U.S. Government. That guide concludes "With proper techniques and safety precautions, uranium and uranium alloys can be safely machined by most shops." Exotic techniques like robotic handling and machining in a liquid bath weren't required. They didn't even use a glove box back then.
Machining plutonium is more difficult. US plants have had troubles with that for decades, and didn't even have a facility that could do it between 1989, when Rocky Flats shut down, and 2002, when Los Alamos started up. But Iran is taking the uranium route, so they don't have to worry about that.
The explosive components have to be made very uniform, to get the uniform compression required. This was a big problem for Los Alamos in the early days, but now that everyone has plastic explosives, it's easier. There's also a problem with the explosion blowing out at the gaps between explosive blocks, but there's a simple trick to fix that. (It's classified in the US, but has leaked out from the USSR side.)
The necessity for krytron detonator switches is overrated. A krytron is a gas-filled tube device from the era of the thyatron. Basically, you need a switch for about 1000 amps at 1KV that turns on in a few nanoseconds. Conveniently, the U.S. Government distributes a design using standard IGBT semiconductors. That's 15 years old; you could probably downsize that design (10" of rack space) today.
Most of the complexity in bomb design appears as bombs are made physically smaller. Truck-bomb sized units are 1940s technology. Smaller warheads require late 1950s technology, and the US did about a hundred full-scale nuclear tests in the 1950s to get that right. Some of that can be replaced with simulation. Eventually, you have to set one off to be confident it will work.
As Ted Taylor (who designed many US bombs) once said, "Everyone (who built an atomic bomb) has succeeded on the first try."
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Re:Or
However, its a question whether the climate reacts to warming by positive feedback, and if so how strongly, or by negative feedback.
There's a debate about how much positive feedback exists, but the case for negative feedback is very weak. For example, events such as Heinrich and Dansgaard-Oeschger events are the best examples of abrupt climate change in the paleoclimate record. These ancient events are worrying because they show the climate has a propensity to shift quickly from one state to another, given even small forcings. That requires positive feedback.
Also, the estimated magnitude of the Milankovitch cycles and other forcings are insufficient to account for the temperature variations observed in ice cores from Vostok and EPICA. This requires positive feedback. In fact, the estimates of positive feedback are too small to bridge the gap.
The decisive evidence for feedback would be if the climate were now genuinely warming faster than or differently from ever before.
Approximately 35x faster, which isn't surprising because of the unprecedented (in the last 2 million years) CO2 levels. Also, the warming is happening after the CO2 increase, which makes this warming qualitatively different from all previous deglaciations.
And this is where the question of the refusal of the climate science community to reveal their data becomes important.
Proxy data are available, Wahl and Ammann have made their code available, the CMIP3 database makes model output public for researchers to perform comparisons, etc. I've previously complained about the (widespread) tendency of scientists to keep their data private to wring every last discovery out of it before making it public. It's worrying, but not a problem unique to climatology. Nor ar all climatologists so hesitant to release their code and data. I publish all my code under the GPLv3, for instance.
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Not fake
I am sure the guys building this laser would be more than a little pissed that you consider their laser 'fake' because it uses frequency doubling....
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Re:just another bunch of Big Coal shills
For the Nth time - we can't arbitrarily replace current baseload power (coal/nuclear) with wind or PV solar(*) without a major technological advance in energy storage. The current grid supports small-scale contributions from wind and solar only because they're small scale - a grid with more than a few percent of solar or wind would be so unstable as to be unusable without a lot of quick-starting, controllable generating capacity to jump on when the wind/sun fluctuates. Today, that means natural gas or oil-fired systems.
A smart grid could theoretically solve this problem; note, however, that the problems are at least as hard as internet routing, and failures mean blackouts and fires/explosions - we are very unlikely to get it right the first time.
For a better view of the magnitude of the problem, look here.
(*)Thermal solar might work, with big enough heat sinks.
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World's *First* X-Ray Laser? I don't think so.
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Re:Arrgh!
No doubt there are additional losses, but since the power distribution grid is something like 90% efficient, these additional losses are very small compared to the energy savings gained by using a CFL instead of an incandescent.
Not according to the guys at LLNL. Those figures are apparently in quads, or quadrillion BTUs generated/used/lost in 2002.
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mod parent up!Mod parent up! The grand parent is mistaken. Studying fusion is the secondary mission for the NIF, the primary mission is to aid in the design of better nuclear weapons. From the NIF facts document on this page:
The National Ignition Facility (NIF) will use the world's largest laser to compress and heat BB-sized capsules of fusion fuel to thermonuclear ignition. NIF experiments will produce temperatures and densities like those in the Sun or in a nuclear weapon. The experiments will help scientists sustain confidence in the nuclear weapon stockpile without nuclear tests as a unique element of the National Nuclear Security Administration's Stockpile Stewardship Program and will produce additional benefits in basic science and fusion energy.
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Re:Inertial confinement vs. magnetic confinement
Go to the NIF site. What are the first things you see?
NATIONAL IGNITION FACILITY AND PHOTON SCIENCE: THE POWER OF LIGHT
Schwarzenegger touts NIF energy innovations
Creating a miniature star on Earth: that's the goal of the National Ignition Facility (NIF), the world's largest laser. When ignition experiments begin in 2010, NIF will focus the intense energy of 192 giant laser beams on a BB-sized target filled with hydrogen fuel â" fusing, or igniting, the hydrogen atoms' nuclei. This is the same fusion energy process that makes the stars shine and provides the life-giving energy of the sun.
Missions:
National Security
Energy for the Future.
You can't tell me that there isn't a very deliberate marketing plan being put into action here.
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Re:NIF is about nuclear weaponry, not energy.
Unfortunately, National Ignition Facility has nothing to do with energy production and everything to do with nuclear weaponry.
It does have a lot to do with energy production. It is the first step towards LIFE.
LIFE, an acronym for Laser Inertial Fusion-Fission Energy, is an advanced energy concept under development at Lawrence Livermore National Laboratory (LLNL). Based on physics and technology developed for the National Ignition Facility (NIF), LIFE has the potential to meet future worldwide energy needs in a safe, sustainable manner without carbon dioxide emissions.
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Re:Sorry, can't get worked up over it
Its funded by the DOD, not DOE. Its primarily for research and stockpile stewardship. NIF isn't intended to be a prototype fusion reactor for energy production.
LLNL is funded by NNSA which is part of DOE.
Yes it is primarily for research and stockpile stewardship, but it is also the first step towards LIFE , which is a prototype reactor.
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Re:NIF is about nuclear weaponry, not energy.
Apologies for the self followup, but the evidence for the above is publicly available:
"NIF is a program of the U.S. Department of Energy's National Nuclear Security Administration. "
NNSA is the section of DOE which operates the production and analysis of nuclear weapons.
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Re:Inertial confinement vs. magnetic confinement
Let's be clear here. The purpose of the NIF is not to achieve fusion for energy production purposes. They just sell it that way.
They are not trying to sell NIF as the fusion energy production. It is the first step on a long road in that direction.
They are selling LIFE as the fusion energy of the future, this will be built on techonology developed for NIF.
From the link
LIFE, an acronym for Laser Inertial Fusion-Fission Energy, is an advanced energy concept under development at Lawrence Livermore National Laboratory (LLNL). Based on physics and technology developed for the National Ignition Facility (NIF), LIFE has the potential to meet future worldwide energy needs in a safe, sustainable manner without carbon dioxide emissions.
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Re:And
We kind of already do. The NIF has just been finished and 'ignition' just might be achieved this year or early next if all goes according to plan: https://lasers.llnl.gov/newsroom/project_status/index.php
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Babel project
Seriously, they're trying to make multilanguage projects possible (if not easy). Ever want a Java object to inherit from both a Python object and a C++ object? Then Babel is your tool. https://computation.llnl.gov/casc/components/babel.html
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Re:So what about global warming ?
Correct me if I'm wrong (I'm not sure - some of them may be available)
Since you asked:
http://www.giss.nasa.gov/tools/modelE/
http://www.ccsm.ucar.edu/tools/
and some documentation with output (for reverse engineers :)
http://www-pcmdi.llnl.gov/ipcc/model_documentation/ipcc_model_documentation.php
I believe some grants/universities do forbid open sourcing code, or even making it available, at least fro some time. -
similar to the LIFE project at NIF
How are they going to run the fusion part? The article doesn't say. In fact it's not clear what the innovation is here. The LIFE proposal from LLNL would use ICF fusions.
http://lasers.llnl.gov/missions/energy_for_the_future/life/
-Carl
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Don't let the facts get in the way
If everybody in the US switched to commuting in a Prius tomorrow, it would have a negligible impact on total CO2 production (the vast majority of CO2 comes from electricity generation)
Negatory. In 2002 tUSA consumed the following energy (quads) source:
8.1 nuclear power
2.6 hydro
2.3 biomass
23.2 nat gas
22.6 coal
39.2 oilThe oil goes almost universally for transportation. The coal goes almost universally for electricity [as does hydro and nuclear power]. About 20% of nat gas goes for elec, the rest for industrial and residential heat processes.
If everyone switched to a Prius tomorrow, our fuel consumption would go down by [pulled out of my butt] 60%. That means our CO2 emissions would drop by at least 30% [since nat gas, hydro, and nuke have lower C02 per unit energy]. That, sir, makes you quite wrong.
Additionally, the statement
Energy efficiency and CO2 production are only weakly related
has me scratching my head too. When we burn fossil fuels we get CO2. The energy efficiency is the percentage of CO2 that goes toward useful work is it's energy efficiency. Every joule, kWh, gallon of gas, etc that's not wasted is CO2 not spewed in the air for no useful purpose. No sir, energy efficiency and CO2 are directly related.
Finally (with asbestos underwears on) I'd remind you that nuclear power is not CO2 free. Not only is there plenty of CO2 involved in the construction of the plant itself thanks to the loads of concrete, construction equipment, etc., but the nuclear fuel doesn't come from flowers grown in the front lawn -- it has to be mined, often in Australia, and then shipped to the power plants. Less CO2 than coal? For sure. Than nat gas? Yip. But, not zero. Will nuclear power be part of the get-off-carbon solution? I'm not sure. If wind, solar, biomass, geothermal, and efficiency are enough to get us by, I hope we don't build more nuclear. If those other things aren't, let the new generation of nuclear power begin, but only as much as can't be provided by these other non-carbon means which don't rely on dangerous fuels from other nations.
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Re:Infrastructure, infrastructure, infrastructure.
A good place to start would be to recycle the waste into more energy production (currently illegal, regardless of the economics).
If the French can figure this out (80% nuclear powered country and growing) and we can't, then that is pretty pathetic.
Also, take a look at this https://lasers.llnl.gov/
Lawrence Livermore is making some really good progress on fusion. I know its cliche, but if we poured 1/10th the Iraq war money into fusion research we would have it pretty darn quickly.
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Re:Holy Mackerel!
Livermore has some seriously big lasers, including a 750 Terawatt number that creates tiny, short-lived "sun's". Don't point that one in your eye!
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It's <= 1kJ in any case
This is the most powerful laser at the facility, firing 2x1kJ per hour.
In any case, I think that Goldmember would disapprove of such practices with gold
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PThreads & Java Threads
However I am looking for a good book on programming threads from an applied point of view. I am looking for one or more texts that provide thorough coverage and provide meaningful exercises. Anyone have any ideas?
I went through grad school not too long ago for Computer Science (disclaimer: it was the kind of computer science degree that doesn't focus on hardware so I might not be the best expert on this). Anyway there were two books for the class.
One dealt with coding regular old C on a plain jain Unix machine and method of (I believe there are others) doing multithreaded in that environment is PThreads (or the super short overview). The book we used is the Addison Wesley book (ISBN 0-201-63392-2). It was informative and comprehensive ... wasn't concentrated specifically on applications like you ask but very good reference. Also, I think there are a lot of good books free online in respect to that topic.
As for Java, there was an O'Reilly book (there's probably a new version out for Java 6) that was pretty good. Not as great of a reference but better on applications of threads in Java. Although, as far as introductory material, I personally learned it all from java.sun.com. Although I can't vouch for whether this is an applied approach or not, I would suggest the concurrency tutorial and a good book on Java Patterns or even a design pattern wiki.
I've never done concurrent programming in C# or Python so I do not know first hand what is best. I do know that erlang has been fun to mess around with in my spare time though!Recently I have been incorporating them more in my solutions for clients.
Most important rule of thumb of multi-threaded programming is to avoid it if possible. Maybe hardware (multi-core) will change that, maybe you feel the scheduler can't do its job as well as you can and maybe you feel it's more intuitive. But, often is the case, that you're just adding more complexity to your code resulting in more difficult bugs and harder maintenance for others. Keep it simple.
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PThreads & Java Threads
However I am looking for a good book on programming threads from an applied point of view. I am looking for one or more texts that provide thorough coverage and provide meaningful exercises. Anyone have any ideas?
I went through grad school not too long ago for Computer Science (disclaimer: it was the kind of computer science degree that doesn't focus on hardware so I might not be the best expert on this). Anyway there were two books for the class.
One dealt with coding regular old C on a plain jain Unix machine and method of (I believe there are others) doing multithreaded in that environment is PThreads (or the super short overview). The book we used is the Addison Wesley book (ISBN 0-201-63392-2). It was informative and comprehensive ... wasn't concentrated specifically on applications like you ask but very good reference. Also, I think there are a lot of good books free online in respect to that topic.
As for Java, there was an O'Reilly book (there's probably a new version out for Java 6) that was pretty good. Not as great of a reference but better on applications of threads in Java. Although, as far as introductory material, I personally learned it all from java.sun.com. Although I can't vouch for whether this is an applied approach or not, I would suggest the concurrency tutorial and a good book on Java Patterns or even a design pattern wiki.
I've never done concurrent programming in C# or Python so I do not know first hand what is best. I do know that erlang has been fun to mess around with in my spare time though!Recently I have been incorporating them more in my solutions for clients.
Most important rule of thumb of multi-threaded programming is to avoid it if possible. Maybe hardware (multi-core) will change that, maybe you feel the scheduler can't do its job as well as you can and maybe you feel it's more intuitive. But, often is the case, that you're just adding more complexity to your code resulting in more difficult bugs and harder maintenance for others. Keep it simple.
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Why the lenses? There's a better way!
This telescope is amazing. The three-mirror configuration gives sharp focus, over a very wide field...the only problem is that the focus is on a spherical surface.
The LSST fixes this by having three relatively small (small compared to the mirrors) lenses to flatten the field, and they use a very large image sensor.
I am curious if they considered using a non-flat image sensor. It would be hard, but with e-beam or UV-laser lithography, I would think that you would be able to build a big sensor on a curved surface, and eliminate the inevitable light loss, distortion, chromatic abberations, and other problems with lenses.
This is something that could be added in the future, too, much as Hubble was modified after-the-fact. It just seems to this layman that it's too good an idea to pass up.
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Current project
Funnily enough this is a project I am working on right now.
I'm coming at it from an HPC (high performance computing) perspective. We'll have a cluster in-house supporting the base load and overflow to a utility computing provider.
Job scheduling software (currently torque but also trialing slurm) is used and once the total load has passed a threshold more remote compute VMs are fired up.
We should have it in production by -
/me checks gantt chart - last month.It seems like an idea whose time has come.
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Re:Excellent!!
By contrast, CA-signed certificates can't be forged without first breaking (or otherwise acquiring) an established CA's signing key.
Someone ought to tell Verisign that.
A CA-signed certificate guarantees that your data can only be decrypted by the intended recipient. There's no way to tell whether a self-signed certificate belongs to the intended recipient or a MITM, which renders the encryption useless against a determined attacker.
No, they don't.
It guarantees it using a very narrow definition of guarantee that is orthogonal to reality: The point of a CA is that if the user trusts Verisign's judgement, and Verisign says they trust eaeaea1234 is "Microsoft Corp", then the user can decide whether they can chose to decide whether they trust "Microsoft Corp" or not.
That means trusting "Microsoft Corp"'s judgement, and their track record with keeping things secure. It also means trusting Verisign's judgement, and their track record with keeping things secure.
If "Microsoft Corp" isn't Microsoft Corportation, or Microsoft Corporation cannot keep their keys safe, then the certificate adds no security whatsoever.
If you (the user) cannot trust Verisign to handle that verification process completely, then the act of having a CA adds no security at all.
Moreover: Because users are being told (by people "good at computers" like you, no doubt) that CA certificates make them secure, they believe as long as it says "Microsoft Corp", that their information is safe.
Please stop perpetuating myths about SSL. It's broken. It's been broken for a long time.
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All of which Bechtel Corp.is capable of overcoming
As far as compiling suspect lists (the type of thing you are supposed to do in criminal investigations, Bechtel Corp. would top the list.
Means: Bechtel is the largest engineering co. in the US. Bechtel is a leader in the field of demolitions technology. Bechtel manages the Lawrence Livermore Labs a particularly suspicious form of nano-thermite was researched and developed and discussed in this April, 2000 scientific journal article.
Making Nanostructured Pyrotechnics in a Beaker
A.E. Gash, R.L. Simpson*, T.M. Tillotson, J.H. Satcher and L.W. Hrubesh
Energetic Materials Center
Lawrence Livermore National Laboratory
Livennore, CA 94550Abstract
"Controlling composition at the nanometer scale is well known to alter
material properties in sometimes highly desirable and dramatic ways. In the field
of energetic materials component distributions, particle size, and morphology,
effect both sensitivity and reactivity performance. To date nanostructured
energetic materials are largely unknowns with the exception of nanometer-sized
reactive powders now being produced at a number of laboratories. We have
invented a new method of making nanostructured energetic materials, specifically
explosives, propellants, and pyrotechnics, using sol-gel ~hemistry.lT-~he ease of
this synthetic approach along with the inexpensive, stable, and benign nature of
the metal precursors and solvents permit large-scale syntheses to be carried out.
This approach can be accomplished using low cost processing methods. We will
describe here, for the first time, this new synthetic route for producing metaloxide-
based pyrotechnics. The procedure employs the use of stable and
inexpensive hydrated-metal inorganic salts and environmentally friendly solvents
such as water and ethanol. The synthesis is straightforward and involves the
dissolution the metal salt in a solvent followed by the addition of an epoxide,
which induces gel formation in a timely manner. Experimental evidence suggests
that the epoxide acts as an irreversible proton scavenger that induces the hydratedmetal
species to undergo hydrolysis and condensation to form a sol that undergoes.
further condensation to form a metal-oxide nanostructured gel. Both critical point
and atmospheric drying have been employed to produce monolithic aerogels and
xerogels, respectively. Using this method we have synthesized metal-oxide
nanostructured materials using Fe3', Cr3+, A13', Ga3+, In3', Hf', Sn4+and Zr4+
inorganic salts. Using related methods we have made nanostructured oxides of
Mo, Ti, V, Co, Ni, Cu, Y, Ta, W, Pb, B, Pr, Er, Nd and Si. These materials have
been characterized using optical and electron microscopy, infrared spectroscopy,
surface area, pore size, and pore volume analyses.
The epoxide addition sol-gel technique is amenable the addition of
insoluble materials (e.g., metals or polymers) to the viscous sol, just before
gelation, to produce a uniformly distributed and energetic nanocomposite upon
gelation. As an example energetic nanocomposites of Fe,O, and metallic
aluminum are easily synthesized. The compositions are stable, safe and can be
readily ignited. Production and characterization data of these novel energetic
materials will be presented...."https://e-reports-ext.llnl.gov/pdf/247064.pdf
There's been THERMITE RESIDUE in every single sample of WTC ash that's been tested so far by independent labs.
http://journalof911studies.com/volume/2008/Ryan_NIST_and_Nano-1.pdf
http://journalof911studies.com/articles/WTCHighTemp2.pdf
Motive: The 9/11 destruction of WTC 7 destroyed the evidence that had been gather for the case the Departmant of Justice was building against Bechtel in "THE BIG DIG" corruption scandal.
Since 9/11, the only corporation recieving more Iraq/Afghanistan contracts than Bechtel is Halliburton.
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Er, hasn't xCAT been open source for years?
I mean, it has a SourceForge page whose mailing list archives go back to 2001, fer cryin' out loud.
Now some of the "OpenHPC" stuff appears to be new, but not all of it appears to originate from IBM. For instance, part of it appears to be a repackaging of the SLURM batch system from LLNL. The one thing that looks like a genuine contribution from IBM is the "Advance Toolchain" stuff, but even that appears to draw heavily from existing open source code bases like valgrind.
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Re:Nice, but lets keep it real.
Plus you've got to somehow figure out how to cut up rocks in a predictable fashion using nuclear weapons, for which there is no experience on Earth, let alone in space. Plus all of the problems of a manned interstellar mission. Plus all the problems of landing on an asteroid.
Once again, using nuclear explosives to divert an asteroid does NOT mean blowing them apart. A little (thermal) nudge is sufficient:
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Re:Nice, but lets keep it real.
Also, several studies have indicated that nuking the average asteroid would be worse than pointless.
Which studies are you referring to? Here's one that claims the opposite:
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Re:Nice, but lets keep it real.
Gravity Tractor? You know I love these sky high fantasy ideas to deflect asteroids as much as anyone else but shouldn't we be concentrating on what is real? If an asteroid does threaten Earth in the next few years we will use nuclear demolitions on it. We will not use a gravity tractor, laser beams, or giant snow balls. Nor will we attach plasma engines or mass drivers to it. We will use nuclear demolitions because that is, simply, all we have.
[...]
We wont' use one nuke. We will blowup the big one then we will blow up the smaller ones into smaller pieces. We will do this until the chunks are small enough that the atmosphere will handle. With smaller chunks there is more surface area for the atmosphere to work on. Most importantly the smaller chunks will not "crack the crust" as one fat ass one would.
Blowing up an asteroid isn't necessary, and with only a couple of years' notice, it isn't very effective, either. For details, see:
https://e-reports-ext.llnl.gov/pdf/343984.pdf
Nuclear explosives are a good tool for this job, just not in the way that you think they are.
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Re:nukes
Nukes are better suited for the primary plan:
https://e-reports-ext.llnl.gov/pdf/343984.pdf
However, simply blowing up the asteroid at the last minute (Armageddon-style) won't help much.
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Re:Themoelectrics Already Pretty Good
"A thermoelectric material designed to replace a conventional Freon-gas refrigerator must have a ZT of at least 3."
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Themoelectrics Already Pretty Good
Even though that article linked from the summary says that typical engines in cars get about 25% of the gasoline's energy content into car motion, it's actually about 20%. That's a lot of wasted energy: about 4:1 waste:use.
But lots of combined cycle plants (like CCGT gas turbines) reclaim a lot of their waste heat into more power. Taking a maximum mechanical power extraction of 60% of the gas' energy up to 85% by heating steam, which is an additional 25% of the original mechanical power.
CCGT reclamation tech is probably not practical for vehicles, so this new material is a welcome advance. Especially if the researchers get the zT from its new 1.5 high to its predicted 3.0 or so. But in fact DARPA has funded Trinh Vo at Lawrence Livermore National Labs to grow nanowires that already have a zT at 3.
More of that kind of material research is very welcome, because at zT 3, these materials can replace freon refrigerators with the same electrical efficiency. Since freon refrigerators require lots of energy to build, and then to recycle, replacing them with a simple material that can scale to any size (including very small, as in microelectronics), means a vast sector of modern industry, including transportation, could switch. If making the material is less energy intensive, and less reliant on a limited critical resource than the freon refrigerators or the CCGT reclamation systems, global energy efficiency could take a giant leap.
A leap that could be just around the corner, in Ohio.
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Re:In other news
Oddly enough, that fact is actually the best documented part of what I said. See https://eed.llnl.gov/flow/images/LLNL_Energy_Chart300.jpg for more. Over 50% of energy is simply lost (heat, transportation, and high voltage requirements all play in) during the generation and transportation of energy.
However, it does look like I mistated this. Turns out that over 50% of energy is lost in generation, transmission, and distribution (and not just in transmission and distribution alone). I think the point still stands though