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Comment Re:decay rates based on season? (Score 2, Informative) 408

The astroengine article has a graph from the Jenkins 2008 paper http://arxiv.org/abs/0808.3283

The graph shows variations of order 0.1%. A +-3% seasonal change in orbital radius would give a 6% change in R^2 so the effect is about 1/30 of the effect of the radius change. A change in radius to 1.6 AU should cause a drop to 40% of "solar particle" flux hence about 1.3% change in radioactive heat and thus RTG output, or about 10W. The power output measurement appears to have sufficient precision to show such a drop. Cooper does a much better job than I have with these back of the envelope estimates.

Coopers paper is http://arxiv.org/abs/0809.4248

Definitely a puzzle nuclear physicists should be looking at.

Comment Re:Was this one of Obama's first things to do? (Score 3, Informative) 388

Both Bush and Obama differentiated between creation of embryonic stem cells and their use in research. Bush did not allow the use of stem cell lines created after ~2000. Obama allowed the use of stem cell lines created with private funds in federal research. Both administrations viewed this as consistent with the 1996 law which prohibited Federal funds from being used to destroy embryos as the stem cell lines were created with private funds. The judge wrote that one can't make this distinction between funds used to create the lines and funds for research using the lines, that the law prohibits all research using embryonic stem cell lines. I trust that the Department of Justice will appeal.

The judge was a Reagan appointee.

Comment IEEE style guide; arxiv (Score 4, Informative) 279

http://standards.ieee.org/guides/style/ is the page with the IEEE style guides.

http://standards.ieee.org/guides/style/2009_Style_Manual.pdf is the guide itself.

If your paper agrees with this it shouldn't be too hard to change it later to fit into the particular style requirement of the final journal.

You can also go to http://arxiv.org/ and read some of the papers in the Math or Computing Science sections closest to your topic to see the styles in the field.

Comment not bad solder - human safety concerns (Score 1) 1

Key sentences in Nature article as I read it: "Making the second connection to the stabilizer with a different type of solder that had a lower melting point could have avoided the problem. Lyn Evans, who oversaw the LHC from 1994 to 2009, says that the idea was considered and rejected because the alternative solder contained lead, a hazard to workers."

One has to keep the peak temperature the superconductor sees in processing, including soldering, down to keep critical current up. Two soldering operations are needed to complete the splice. Both solders have to have liquidus temperatures higher than the temperature likely to be seen during a fault and lower than the allowable superconductor processing temperature. This is typically done with a silver-tin solder for the first join and lead-tin for the second. CERN decided to use the same alloy for both joints to prevent exposure of their workers to vapor from a lead alloy solder. Respirators could have been used but the vapor would have been deposited on all surfaces in the tunnel - the distances are long between air inlets/outlets - perhaps causing a long term maintenance hazard. The QA equipment needed to check for solder voids wasn't available for most of the installation due to problems in its development, per Rossi.

Comment "shorts towers" (Score 1) 572

In a science fiction story of the 50's whose author I can't remember there was an eccentric inventor named Shorts. The character was used in several stories. One involved the invention of "Shorts towers" of exactly the sort described. But they had multiple purposes. The first was erected in a desert with an inflatable dome as the greenhouse. Not only was power provided - so was water, through condensation as the hot air ascended and cooled off. The humidity is low, but there's some water vapor to condense.

Or they were used in reverse, as city air conditioners. Dome a city. Erect a tower. Use fans to bring cold air down from altitude. You need the fans because of the density gradient.

Does anyone remember the story and author?

Comment Re:Is there plenty in Russia? (Score 1) 224

RTFA. It states that He-3 is being supplied comercially by the US and Russia. Total available ~20,000 liters/year. With DHS, annual requirement is 65,000 liters/year. I've seen another article, which I didn't bother to search for, which suggested the Russian's had cut back on selling the stuff until the price went up still more.

Comment another way to make tritium (Score 2, Interesting) 224

International Committee on Future Accelerators Beam Dynamics section newsletter abstract under the URL.

While the emphasis in the six articles is on transmutation of nuclear waste and accelerator driven nuclear power plants, the same accelerators can generate neutrons to breed tritium from lithium. The fusion demonstration ITER will have blanket with lithium to demonstrate breeding since its fuel is a deuterium-tritium mixture.

It would be lovely for the US accelerator community if the US DHS forked over $1.5B for a system to breed tritium and, in its spare time, transmute long lived waste isotopes so used fuel rods would decay to radiation levels below that of natural uranium ore within one thousand instead of one hundred thousand years.

http://www-bd.fnal.gov/icfabd/Newsletter49.pdf

The theme is "Accelerator Driven Sub-Critical Assemblies (ADS) and its challenge to accelerators." This is a topic that could have a deep impact on the future of our society. As we all know, developing clean energy and protecting the environment are two top priorities in countries around the world. ADS is an accelerator-based technology that may provide a viable solution to these major problems. Jiuqing collected 6 excellent articles in the theme section. They give a comprehensive review of this important accelerator field, including valuable lessons learned from the past.

Comment accelerator driven subcritical reactors and waste (Score 1) 581

The International Committee on Future Accelerators periodically publishes "newsletters" with a theme. The most recent newsletter is on the subject given above. It may be obtained at

http://www-bd.fnal.gov/icfabd/

The theme is "Accelerator Driven Sub-Critical Assemblies (ADS) and its challenge to accelerators." This is a topic that could have a deep impact on the future of our society. As we all know, developing clean energy and protecting the environment are two top priorities in countries around the world. ADS is an accelerator-based technology that may provide a viable solution to these major problems. Jiuqing collected 6 excellent articles in the theme section. They give a comprehensive review of this important accelerator field, including valuable lessons learned from the past.

Comment virginia deposit good for two months (Score 2, Informative) 581

Virginia land hides huge uranium deposit

First URL is UPI story. Second is abstract of a scholarly paper from Virginia Tech.

http://www.upi.com/Top_News/2008/01/02/Virginia-land-hides-huge-uranium-deposit/UPI-69751199296526/

http://www.geoinformatics.vt.edu/server/docs/jjerden/NA99l.htm

Estimated content 55,000 tons uranium per UPI. The second suggests ~40,000 tonnes of uranium, ~40 million tonnes of 0.1% ore. If the 0.1% ore is itself the usual 0.7% U235, then ~10,000 tonnes of 3% enriched would net from the ore body.

Comment Baen Free Library (Score 1) 1021

http://www.baen.com/library/defaultTitles.htm/ to save the students money

Agent of Vega or another one of the James Schmitz selections
Crown of Slaves - David Weber (Harrington universe) - long
Mother of Demons - Eric Flint
Mountains of Morning - Lois McMaster Bujold
Oath of Swords - David Weber fantasy
Pandora's Legion - Christopher Anvil
Sleipnir - Linda Evans
A Logic Named Joe - Murray Leinster
Starliner - David Drake

and many others

Comment industry: accelerator transmutation nuclear waste (Score 1) 552

An industry which could create a few hundred thousand jobs, transmute existing long-lived nuclear waste to short-lived stuff, generate power with minimum CO2, etc. Total R&D cost, including prototype at full commercial scale, under $10B. A proton accelerator with ten times the power and same energy as the Spallation Neutron Source in Oak Ridge can be used to drive a sub-critical nuclear power system or to transmute existing nuclear waste or both. There is basic R&D and a lot of engineering needed. R&D and prototype cost would be less than ITER, the International Tokamak Experimental Reactor (fusion). Lots of messy politics because of concern about nuclear weapons proliferation, however. And NIMBY. No chance of an uncontrolled reaction, since turning off the proton beam stops the reaction in under a microsecond (speed of light from source to target).

http://scholar.google.com/scholar?hl=en&q=rubbia+accelerator+transmutation+nuclear+waste&btnG=Search/

Carlo Rubbia proposed this around 1990, six years after his Nobel prize. http://en.wikipedia.org/wiki/Carlo_Rubbia/

https://accelconf.web.cern.ch/accelconf/e94/PDF/EPAC1994_0270.PDF/
A High Intensity Accelerator for driving the energy applifier for nuclear energy production. C. Rubbia et al.

Another citation: http://arjournals.annualreviews.org/doi/abs/10.1146%2Fannurev.nucl.48.1.505/
ACCELERATOR-DRIVEN SYSTEMS FOR NUCLEAR WASTE TRANSMUTATION (1998 review)

Charles D. Bowman
The ADNA Corporation, Accelerator-Driven Neutron Applications, Los Alamos, New Mexico 87544; e-mail: cbowman@roadrunner.com

  Abstract The renewed interest since 1990 in accelerator-driven subcritical systems for transmutation of commercial nuclear waste has evolved to focus on the issue of whether fast- or thermal-spectrum systems offer greater promise. This review addresses the issue by comparing the performance of the more completely developed thermal- and fast-spectrum designs. Substantial design information is included to allow an assessment of the viability of the systems compared. The performance criteria considered most important are (a) the rapidity of reduction of the current inventory of plutonium and minor actinide from commercial spent fuel, (b) the cost, and (c) the complexity. The liquid-fueled thermal spectrum appears to offer major advantages over the solid-fueled fast-spectrum system, making waste reduction possible with about half the capital requirement on a substantially shorter time scale and with smaller separations requirements.

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