Slashdot Mirror

I just completed the lecture series for this course to prep for a prelim, as I'm out of practice in Linear Algebra. Wonderfully done. If I pass I'm going to find a way to buy him a beer in MA from CA. If I ever get a real academic job then I'm donating to the program. It's got to be one of the best education paradigms I've ever seen. See the other courses with full video at http://ocw.mit.edu/OcwWeb/Global/OCWHelp/avocw.htm .

If you click the ".rm" link, it takes you to a page that says:
.rm RealOne(TM) Player software is required to run the .rm files found on a course site.


Also, it seems that OCW is Free as in speech:
http://ocw.mit.edu/OcwWeb/Global/terms-of-use.htm You are free:

* to copy, distribute, display, and perform the work
* to make derivative works
Under the following conditions:
Attribution. You must attribute the work in the manner specified by the author or licensor.
Noncommercial. You may not use this work for commercial purposes.
Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one.

GNU may not like the "noncommercial" clause, but I consider something free even if it has a noncommercial clause.

If you click the ".rm" link, it takes you to a page that says:
.rm RealOne(TM) Player software is required to run the .rm files found on a course site.


Also, it seems that OCW is Free as in speech:
http://ocw.mit.edu/OcwWeb/Global/terms-of-use.htm You are free:

* to copy, distribute, display, and perform the work
* to make derivative works
Under the following conditions:
Attribution. You must attribute the work in the manner specified by the author or licensor.
Noncommercial. You may not use this work for commercial purposes.
Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one.

GNU may not like the "noncommercial" clause, but I consider something free even if it has a noncommercial clause.

The course is no longer available following the link in the article.

The new link is:

http://ocw.mit.edu/OcwWeb/Electrical-Engineering-a nd-Computer-Science/6-912January--IAP--2006/Course Home/index.htm

http://ocw.mit.edu/OcwWeb/Electrical-Engineering-a nd-Computer-Science/6-912January--IAP--2006/Course Home/index.htm

from the groklaw site seems to work

Here's the actual link:
Course 6.912

bad url perhaps...

I used to use slrn (news reader) and jed (editor), they're both written using slang and both are fine programs. All have the same author - John E. Davis. So I would certainly look at slang.

That said, ncurses is the standard, it is mature, it is well known. You'd need to have some pretty special requirements before ncurses wasn't the best option, I think.

Don't be so sure. The foil hats themselves are most likely part of a government conspiracy to control your mind.

What you're talking about is the photonic crystal.

The Problem is the loss is WAY too high for practical use.

Come on man, I just finished Structure and Interpretation of Computer Programming and I loved it! How could you not love the flexibility of Lisp/Scheme.... Mod points for you buddy!

Would be Hirsute Ceramist and the Holy Lambda for those of us who like Lord Voldemort's Schemes.

If you don't know how to write code to utilize all of the CPUs, then, well, you can't utilize all of the CPUs. The number of people who know how to write good parallelized code are few and far between. MIT is even teaching a course on how to program the PS3: http://cag.csail.mit.edu/ps3/.

Yeah, that's why we don't have any idea what anybody might have said (or meant) more than a thousand years ago.

I just looked up GRbs, and found this page, which seems to say that they're distributed equally. Also that they are from the beginning of the universe. But I don't know much about this, and may well be wrong.

I wasn't about to go all Max Tegmark... Interesting ideas, though.

Emotion in media does not have much to do with screen resolution in fact surprisingly the opposite is true.

It seems that media (called cool media) where the consumer's brain can fill in the blanks is more emotionally immersive. Interactivity also cools the media which is why /. is so much more fun than the newspaper.

If you're interested in that sort of stuff then there is simply no better book than Marshall McLuhan's "Understanding Media:The Extensions of Man".

Here's the Wiki page on McLuhan for those who don't read dead trees http://en.wikipedia.org/wiki/Marshall_McLuhan

Something like the Wii invokes emotion by an inductive process of using physical sympathy with the character to create immersion and emotional empathy. This is why HD graphics were not a priority on the Wii.

I've actually designed and done proof of concept on a system where a galvanic skin response meter is used along with a coil for breath rate and a pulse monitor to determine changes in stress levels.

This is great for horror games.
By exposing the user to a calibration sequence of stimuli like spiders, rats, simulated falling etc you can fairly accurately determine what really freaks people out and use that against them.

The effect is that if rats scare them then rats will scurry out of every corner. If spiders make their blood run cold then the place will crawl with them.
It's kind of like dynamically generating their own personalized nightmare.

It's a simple database selection to change one type of monster to another and if I ever get funding for it then you'll see just how emotionally interactive a video game can be.

Here's a link to the affective computing project at MIT http://affect.media.mit.edu/index.php

They've done some great lab/theory work but failed to put it to any good use as is typical of academia.

Opera on the green machine

On Friday, I received a call from Opera's accounting department. That normally means trouble. My warning lights starts flashing.

There's a package for you waiting here. I'm looking for the invoice for customs purposes. Can I open it?

Sure, I said, hoping to quickly return to whatever I was doing.

There's no invoice inside. Strange. The value has been declared to be 100 dollars

100 dollars?

Yes. There's a machine inside the package. It's cute. Green.

GREEN? A GREEN MACHINE? 100 DOLLARS?

Yes.

DON'T MOVE. DON'T LET ANYONE ELSE SEE IT. LOCK THE DOORS. I'LL BE RIGHT THERE!

--> -->

As the alert reader has figured out by now, the machine inside the box was a prototype of the $100 laptop from the OLPC project. Since then, I've kept the machine close to me, but lots of people around here have seen it. The Opera geeks gathered around it at the Friday night beer bash. Someone suggested testing to see if the machine could keep running in rough environments. For example, would the rubbery keyboard withstand beer? Better not try.

Invariably, the machine gets attention. It attracts people more than any other unit I've seen. (Only Wii comes close.) People want to see it, touch it, and feel it. They want to know why the USB ports are placed where they are (on both sides of the screen), how the SD card can be inserted (the SD port is under the screen), and where the crank is. The crank, meant to generate power to run the machine, was part of an early design. It has been replaced with a foot pedal which is still under construction. However, it seems that people somehow got emotionally attached to the hand crank and want it back.

Once the machine is turned on, a Linux boot sequence appears. Red Hat is one of the sponsors and the machine comes with a tuned version of Fedora. New boot images are published regularly, and the first thing to do was to install the latest build. All of this is documented at the project's Wiki. The next thing to do was to find a shell. The magical key combination is Alt-Shift-F11. However, the keys don't have function numbers and finding F11 requires counting. When you get it right, a shell appears and you can start typing. Typing would have been easier if my hands were smaller. That's a feature, not a bug.

For me, the next thing to do was to install Opera. This is also the reason why the OLPC people are kind enough to send us an early prototype: we want to make sure the machine has a choice of good browsers. The browser is easily the most important application on the machine. In fact, a modern browser is more than an application — it could be the platform onto which OLPC applications are built, like Opera Platform is for mobile phones. OLPC has decided to only include open source software on the machine. I have discussed this issue at length with Nicholas, Walter and Mako. At Opera, we think that what really counts is open standards. It's less important what runs inside the box as long as what crosses the wire is standards-compliant. They argue that, in an education project, students must be allowed to peek inside the box. That's nice, I say, but if Opera makes the difference between a usable or an unusable machine, perhaps you will reconsider?

Getting Opera to run was quite simp

Opera on the green machine

On Friday, I received a call from Opera's accounting department. That normally means trouble. My warning lights starts flashing.

There's a package for you waiting here. I'm looking for the invoice for customs purposes. Can I open it?

Sure, I said, hoping to quickly return to whatever I was doing.

There's no invoice inside. Strange. The value has been declared to be 100 dollars

100 dollars?

Yes. There's a machine inside the package. It's cute. Green.

GREEN? A GREEN MACHINE? 100 DOLLARS?

Yes.

DON'T MOVE. DON'T LET ANYONE ELSE SEE IT. LOCK THE DOORS. I'LL BE RIGHT THERE!

--> -->

As the alert reader has figured out by now, the machine inside the box was a prototype of the $100 laptop from the OLPC project. Since then, I've kept the machine close to me, but lots of people around here have seen it. The Opera geeks gathered around it at the Friday night beer bash. Someone suggested testing to see if the machine could keep running in rough environments. For example, would the rubbery keyboard withstand beer? Better not try.

Invariably, the machine gets attention. It attracts people more than any other unit I've seen. (Only Wii comes close.) People want to see it, touch it, and feel it. They want to know why the USB ports are placed where they are (on both sides of the screen), how the SD card can be inserted (the SD port is under the screen), and where the crank is. The crank, meant to generate power to run the machine, was part of an early design. It has been replaced with a foot pedal which is still under construction. However, it seems that people somehow got emotionally attached to the hand crank and want it back.

Once the machine is turned on, a Linux boot sequence appears. Red Hat is one of the sponsors and the machine comes with a tuned version of Fedora. New boot images are published regularly, and the first thing to do was to install the latest build. All of this is documented at the project's Wiki. The next thing to do was to find a shell. The magical key combination is Alt-Shift-F11. However, the keys don't have function numbers and finding F11 requires counting. When you get it right, a shell appears and you can start typing. Typing would have been easier if my hands were smaller. That's a feature, not a bug.

For me, the next thing to do was to install Opera. This is also the reason why the OLPC people are kind enough to send us an early prototype: we want to make sure the machine has a choice of good browsers. The browser is easily the most important application on the machine. In fact, a modern browser is more than an application — it could be the platform onto which OLPC applications are built, like Opera Platform is for mobile phones. OLPC has decided to only include open source software on the machine. I have discussed this issue at length with Nicholas, Walter and Mako. At Opera, we think that what really counts is open standards. It's less important what runs inside the box as long as what crosses the wire is standards-compliant. They argue that, in an education project, students must be allowed to peek inside the box. That's nice, I say, but if Opera makes the difference between a usable or an unusable machine, perhaps you will reconsider?

Getting Opera to run was quite simp

For example, the "perfect lens," a term coined by Pendry of Imperial College in London for a slab of negative index acting as a lens, can image sources with sub-wavelength spacing with contrast at least a factor of 5 better than the equivalent near-field system with positive n.

NT stand for Nested Task, it's a register in the 286 that helps preepmtive multi-tasking which is the feature of both OS/2 and NT that distinguishes them from Window 3.x/9x that used co-operative multi-tasking.

http://pdos.csail.mit.edu/6.828/2006/readings/i386 /s04_01.htm

4.1.1 Systems Flags
The systems flags of the EFLAGS register control I/O, maskable interrupts, debugging, task switching, and enabling of virtual 8086 execution in a protected, multitasking environment. These flags are highlighted in Figure 4-1 .

NT (Nested Task, bit 14)
        The processor uses the nested task flag to control chaining of interrupted and called tasks. NT influences the operation of the IRET instruction .

suggest you also look at http://www.oreillynet.com/mac/blog/2005/11/learn_l isp_from_mitfor_free.html (LISP) and (from the same article) http://mitpress.mit.edu/sicp/full-text/book/book.h tml (Structure and Interpretation of computer programs) - read the introduction and preface. There are also a bunch of supplemental videos that you could use. Hope this helps.

http://www.htdp.org/ is a much better book, and depending on the level maturity you can go with http://mitpress.mit.edu/sicp/.

You have the basic experience to continue learning, and pass on the relevant parts to your students. Some resources I would recommend are the MIT Opencourseware and the Berkeley Webcast.

These resources provide two similar but different approaches to learning about computers and programming.

Unfortunately the courts have no clear opinion on this. Lotus vs Borland made it all the way to the Supreme Court but was split 4-4 with one justice recusing himself.

You're noticing the disk driver flush to disk.

Now, this may not make sense at first, but both Windows and Linux do it. I've looked into the reasons linux does it. This seems like a good starter.

I suspect Windows is updating file metadata. You know, the access time on the directory of an open file, or the system event log, etc.

People are generally interested in these sorts of things because they want disks to spin down overnight or on their laptop. It can take a bit of work to get to the point where linux is "stable" and won't write to disk any more, but it's a fun little exercise. Good luck getting Windows that way.

And I thought I sucked at math when I couldn't remember how eigenvectors work the other day...

The numerical solution of differential equations, notably the Navier-Stokes equations was an important stimulus to computing, with Lewis Fry Richardson's numerical approach to solving differential equations. To this day, some of the most powerful computer systems of the Earth are used for weather forecasts.

That would be open to 'forcing' though, as large groups from one party could conspire to follow persons of interest into the booths. That's getting pretty theoretical, but random important guy's (voting) privacy is just as worthy of protection as everybody else's.

Have you seen Rivest's 3 ballot system? Look here:
http://www.schneier.com/blog/archives/2006/10/new_ voting_prot.html
http://theory.csail.mit.edu/~rivest/Rivest-TheThre eBallotVotingSystem.pdf

I haven't read these, but they popped up while tracking it down:
http://www.cs.princeton.edu/~appel/voting/Strauss- ThreeBallotCritique2v1.5.pdf
http://www.cs.princeton.edu/~appel/papers/Defeatin gThreeBallot.pdf

They appear to be of interest.

It's a paper-based voting system that allows you to verify that your vote was cast but doesn't allow you to prove how you voted.
In general terms you vote twice for guy you want, and once for the guy you don't want, leaving your guy +1 over the other. You then are allowed to take a copy (at random) of one the three ballots to walk out with. It has a serial number that is no way related to the other ballots. You use the serial number to check that at least 1/3 of your vote was cast correctly at some later date by checking a bullitin board.

After that it's just a probability game - it wouldn't take that many people to check before it became highly probable that if there was a problem it would be noted.

"There exists a persistent meme that XML is just a new-fangled, verbose form of s-expressions, invented because its inventors did not know about Lisp. This is not the case. XML has explict end-tags with tag-names that match the start-tags because the developers of XML *removed* the feature of SGML that allowed SGML to be more like s-expressions. When we were developing XML, we discussed a variety of alternate syntaxes and joked that if popularity and usability were not factors, we'd choose s-expressions because many of us processed our XML (then SGML) in Scheme-variants anyhow. Scheme was the extension language of the most popular SGML editor and the basis of the only standardized SGML processing language, DSSSL.

"XML's tag-redundancy provides much better error recovery and readability (at a cost of verbosity). S-expressions-as-we-know-them also use the worst possible character for grouping because parens happen so often in ordinary text. XML is not ASCII text, but Unicode, whereas the Common Lisp and Scheme languages predate Unicode. XML allows text directly as content whereas s-expressions require them in quotes.

"I would bet on YAML before s-expressions, but I'd put my money on a government lottery before I'd bet on either of them replacing XML at this point.

"There are already terabytes of bracketed-text flowing around the Internet, and by now gigabytes of that is XML -- at least in source form and often in network form. XML has a raft of related standards that would have to be recreated or at least adapted to work with s-expressions: linking specifications, addressing languages, schema languages, packaging standards, APIs, protocols ...

"Even if parens become incredibly popular as a data structuring language, one can install an S-expression parser for Java in about fifteen minutes. What would motivate people to switch programming languages?" - Paul Prescod

Well, there's a typical Slashdot-centric, OSS zealot response.

Without the useless inflammatory language, you have a point but you could not be more wrong. The mission, according to the MIT site is:

dedicated to research to develop a $100 laptopa technology that could revolutionize how we educate the world's children.

Education is about much more than software but software freedom is essential to the goals of education.

If you can use javascript to help with some more complex positioning (especialy relative resizing and such), XHTML 1.1 really isn't bad at all.

Um. Yes. Yes, it is. XHTML 1.1 is an utterly useless format, but not for reasons having anything to do with CSS; per the W3C's notes on media types for XHTML, XHTML 1.1 should be served with the MIME-type application/xhtml+xml, and never with the MIME-type text/html. But Internet Explorer, even IE7, does not understand this MIME-type (though, to be fair, they've only had seven years to get this right; I figure by the time we have flying cars and robot maids, IE will handle the XHTML MIME-type just fine) and will display its generic "I don't know what to do with this file, do you want to download it?" dialog.

XHTML 1.0 does have provisions for being served as text/html, but there are deep issues with that which most people who use XHTML are blissfully unaware of (hint: all modern web browsers treat XHTML-as-text/html as an unrecognized language, and kick into "tag soup" mode to parse it); if they ever switched to the XHTML MIME-type, or even to an XML MIME-type like application/xml (which works in IE, and is permitted for XHTML but not the recommended thing to use), they'd be in for some nasty surprises.

XHTML, at this point, is basically dead in the water; hordes of people switched to it because it was the latest and greatest, but did so with no understanding of how XML actually works or the constraints created by reformulating HTML in XML. It's only the fact that none of them are actually serving it as XHTML -- because everybody just goes ahead and uses text/html -- that's saved them from their ignorance thus far. Even the W3C seems to have reluctantly accepted this, with Tim Berners-Lee recently announcing that there will be a shift from the "forget HTML, XHTML is the only way forward" mentality to a revival of the HTML working group and a series of gradual refinements and improvements of HTML until (if ever) the world is really ready for XHTML. Which could be a while; a couple years ago, Evan Goer took a sampling of 119 sites which claimed to use XHTML, and tested for valid, well-formed XHTML served using content negotiation to send the proper MIME-type to browsers which understood it. Of the 119 sites -- cherry-picked to include a large concentration of professional web designers and developers, who really ought to know how to do this right -- only one was found to conform, and 74% failed the first step of checking the W3C validator. In the two years since, he's managed to find about a hundred sites on the entire Web which are correctly doing XHTML. 99 sites in two years isn't a rosy picture.

...at least in prototype form? http://www.media.mit.edu/wearables/lizzy/index.htm l The article doesn't articulate how the new technology is different from previous projector-based systems.

http://hacks.mit.edu/Hacks/by_year/2003/wright_fly er/

A lot of people were involved in this. I'm not sure it was the coolest thing each of them ever built, but it was defenitely the coolest thing I've ever built, more for reasons of where it was built than what it was. It never flew, but we did get it higher than the Wright Brothers ever got theirs.

Yep! That's even researched and documented as the Carnival Booth Algorithm

I'm too lazy the read TFA entirely but I can't help from thinking about the Carnival Booth paper: http://www.swiss.ai.mit.edu/6805/student-papers/sp ring02-papers/caps.htm

HAKMEM is classic bathroom reading for hackers. If you want to do it up old-school, print a copy from original scans, double-sided.

uh, are any of you aware of Microsoft Research? i'm not a fan of Redmond, but i do have colleagues who do real research, something a "technical evangelist" doesn't know/get educated about/understand, since it's not directly part of the marketing for their flagship products. there is serious cash being put into R&D at Microsoft for years. they also promote research in Academia; for instance Bill Gates donated 20M to MIT to help start the Computer Science and Artificial Intelligence Laboratory at MIT. http://www.csail.mit.edu/index.php - egad, a building is even named after him! don't hate if you don't know the whole story... http://research.microsoft.com/

It's also worth looking at MIT's RoboTuna and RoboPike, robotic fish, and the penguin boat Proteus. These projects demonstrate that fish-like fins or flippers substantially improve propulsion efficiency vs. propellers, because they generate vortices of water that actually push a vehicle forward. MIT sees these vortices as the answer to Gray's paradox, which said that a dolphin would have to be stronger than it is to swim as fast as it does. (That article disagrees.)

A flapping drive would also have the advantage of looking cool.

It's also worth looking at MIT's RoboTuna and RoboPike, robotic fish, and the penguin boat Proteus. These projects demonstrate that fish-like fins or flippers substantially improve propulsion efficiency vs. propellers, because they generate vortices of water that actually push a vehicle forward. MIT sees these vortices as the answer to Gray's paradox, which said that a dolphin would have to be stronger than it is to swim as fast as it does. (That article disagrees.)

A flapping drive would also have the advantage of looking cool.

In Plastics Day in Surgery, Red Herring reports that an international team of U.S. and German researchers has developed a new kind of plastic that can shift between three different shapes when the temperature increases. Even if these polymeric triple-shape materials have not emerged from the lab, they could eventually be employed as removable stents and self-closing fasteners used by surgeons and more generally by the healthcare industry. But read more

This research work has been done partially at the MIT in Professor Robert Langers research lab. Please note that Ive already covered a previous Langers project in "Light Used to Design Shape-Shifting Plastics" (April 14, 2005).

For this new kind of plastic, Langer worked with Professor Andreas Lendlein, director of the Institute of Polymer Research at the GKSS Research Center in Teltow, Germany, and his team.

This research work has been published online before print by the Proceedings of the National Academy of Sciences (PNAS) under the name "Polymeric triple-shape materials" (November 20, 2006). Here is a link to the abstract.

Shape-memory polymers represent a promising class of materials that can move from one shape to another in response to a stimulus such as heat. Thus far, these systems are dual-shape materials. Here, we report a triple-shape polymer able to change from a first shape (A) to a second shape (B) and from there to a third shape (C). Shapes B and C are recalled by subsequent temperature increases. Whereas shapes A and B are fixed by physical cross-links, shape C is defined by covalent cross-links established during network formation.

The triple-shape effect is a general concept that requires the application of a two-step programming process to suitable polymers and can be realized for various polymer networks whose molecular structure allows formation of at least two separated domains providing pronounced physical cross-links. These domains can act as the switches, which are used in the two-step programming process for temporarily fixing shapes A and B. It is demonstrated that different combinations of shapes A and B for a polymer network in a given shape C can be obtained by adjusting specific parameters of the programming process.

Below is a series of photographs illustrating this triple-shape effect. On the left is a tube which could be used as a stent and on the right is fastener consisting of a plate with anchors. From top to bottom, you can see the shape evolution when the temperature increases to 40C (in B) and 60C (in C). (Credit: MIT/GKSS Research Center). This image has been extracted from the PNAS paper mentioned above.

Picture

In "Morphing Materials Take On New Shapes," Technology Review describes this process in plain English.

Lendlein says the key to the new structures was developing two types of polymers that have distinct melting points. At room temperature, the material holds its first shape. But when heated above a certain temperature, areas throughout the material soften, allowing it to change to an intermediate shape. At a yet higher transition temperature, the rest of the material softens, allowing the structure to take its final shape.

But what would be these

In Plastics Day in Surgery, Red Herring reports that an international team of U.S. and German researchers has developed a new kind of plastic that can shift between three different shapes when the temperature increases. Even if these polymeric triple-shape materials have not emerged from the lab, they could eventually be employed as removable stents and self-closing fasteners used by surgeons and more generally by the healthcare industry. But read more

This research work has been done partially at the MIT in Professor Robert Langers research lab. Please note that Ive already covered a previous Langers project in "Light Used to Design Shape-Shifting Plastics" (April 14, 2005).

For this new kind of plastic, Langer worked with Professor Andreas Lendlein, director of the Institute of Polymer Research at the GKSS Research Center in Teltow, Germany, and his team.

This research work has been published online before print by the Proceedings of the National Academy of Sciences (PNAS) under the name "Polymeric triple-shape materials" (November 20, 2006). Here is a link to the abstract.

Shape-memory polymers represent a promising class of materials that can move from one shape to another in response to a stimulus such as heat. Thus far, these systems are dual-shape materials. Here, we report a triple-shape polymer able to change from a first shape (A) to a second shape (B) and from there to a third shape (C). Shapes B and C are recalled by subsequent temperature increases. Whereas shapes A and B are fixed by physical cross-links, shape C is defined by covalent cross-links established during network formation.

The triple-shape effect is a general concept that requires the application of a two-step programming process to suitable polymers and can be realized for various polymer networks whose molecular structure allows formation of at least two separated domains providing pronounced physical cross-links. These domains can act as the switches, which are used in the two-step programming process for temporarily fixing shapes A and B. It is demonstrated that different combinations of shapes A and B for a polymer network in a given shape C can be obtained by adjusting specific parameters of the programming process.

Below is a series of photographs illustrating this triple-shape effect. On the left is a tube which could be used as a stent and on the right is fastener consisting of a plate with anchors. From top to bottom, you can see the shape evolution when the temperature increases to 40C (in B) and 60C (in C). (Credit: MIT/GKSS Research Center). This image has been extracted from the PNAS paper mentioned above.

Picture

In "Morphing Materials Take On New Shapes," Technology Review describes this process in plain English.

Lendlein says the key to the new structures was developing two types of polymers that have distinct melting points. At room temperature, the material holds its first shape. But when heated above a certain temperature, areas throughout the material soften, allowing it to change to an intermediate shape. At a yet higher transition temperature, the rest of the material softens, allowing the structure to take its final shape.

But what would be these

I submit to you the inventor of the modern dishwasher: Josephine Cochrane.

It's a shame they missed her: http://web.media.mit.edu/~cynthiab/

There are aneutronic fusion reactions. We aren't at the stage where we can use them, but the possibility is there.

No, it's not. Aneutronic fusion is orders of magnitude more difficult to even get going than D-T fusion, and this paper is pretty much a death knell for them. Brehmstrallung losses due to the interactions between fuel ions and free electrons which do not participate in the fusion reaction, become fatal for aneutronic schemes; tritium-tritium, proton-lithium, and proton-boron fusion will in any posited reactor scheme, lose more energy to Brehmstrallung losses than they produce from fusion.

Read the paper. It's (to me) surprisingly accessible for an MIT doctoral thesis.

You're putting the cart before the horse; first you get a self-sustaining reaction then you work out the bugs in the reactor design.

These aren't "bugs" in the reactor design. They are fundamental materials problems; like I said, it is entirely possible that suitable materials simply do not exist. Throwing billions and billions of dollars at mere engineering problems when a materials problem might be a complete game-breaker, rendering all those billions wasted, is not good science.

then it's still too early to say that fixing them "may never be possible".

No. It's too early to say that fixing them will never be possible. But materials problems are of a level beyond that of simple engineering. If they weren't, we'd all be driving around in cars with solid-state lubricants bonded inexorably to all engine surfaces and getting to space in a big elevator to geostationary orbit.

Finally, wasn't the whole idea of using a replaceable lithium blanket supposed to alleviate this?

No. You wouldn't place the lithium *in* the reactor vessel, it would contaminate the plasma and destroy the reaction. The idea is to use lithium to blanket the reactor vessel. Neutrons escaping the vessel would be captured by the lithium blanket. The lithium would heat up, allowing you to extract energy from the reactor and convert it into electricity. Some of the lithium would transmute to tritium. But this says nothing about what you build the reactor vessel out of, except that you want it to let neutrons out. It says nothing about what you build the plasma-facing components out of. It says nothing about how to avoid contaminating the plasma with sputtering from the PFCs.

I disagree with the notion that we should give up fusion R&D

I didn't mean to suggest we should. I just wanted to bring to light an issue that gets very little attention relative to igniting the plasma in the first place. Even if ITER hits Q=10, that won't bring us much closer to commercial fusion (for which you really need Q=20, anyway) than we are right now. For another sticking point, they're still not going to be breeding tritium, and I don't think they're actually going to be turning any of the reactor's power output into electricity. But those are comparatively minor problems.

That's nice. Let him demonstrate how he avoids ion thermalization and proves that the paper is wrong. Saying it's wrong isn't the same thing.

Talking about 'respectable' scientists is dangerously close to saying "The scientists I picked all agree."

Lindzen:

http://en.wikipedia.org/wiki/Richard_Lindzen
http://www-eaps.mit.edu/faculty/lindzen.htm
http://www.realclimate.org/index.php/archives/2006 /04/lindzen-point-by-point/
http://www.sciam.com/article.cfm?articleID=00095B0 D-C331-1C6E-84A9809EC588EF21

May very well be a big-energy shill, crank, or crackpot, but MIT doesn't seem to be working real hard at distancing themselves from him, and he at least comes off as reasonable.

This was discussed a bit in the prior /. article about IEC.

If he does, let's hope he publishes since there appear to be no citations of Rider's thesis a decade after it was published.

Actually, if their goal really is quantum computing, the spin of atomic nuclei would have been a better bet than electron spin. The atomic nucleus is one of the best-isolated quantum mechanical systems known, and it usually takes a very long time for decoherence and similar behavior to destroy any superposition of spin states that you create (an absolute necessity for any type of useful quantum computation). The most promising methods to date (such as this and this) for quantum computation are largely based on nuclear spin. Electron spin superpositions are not only hard to create but they succumb to decoherence very quickly, making them difficult to use.

Since electrons are like photons and they are waves at small scales, it's more about these little probability eddies or whirlpools where the electrons hang out more.

Now, while even people who are experts in the field of quantum mechanics are at a loss to explain what the spin of a quantum particle actually is, this explanation you give is about as far from the phenomenology of spin as it gets. It has nothing to do whatever with "probability eddies" where "electrons hang out more", but is an intrinsic property of the electron or whatever other quantum particle (note that it isn't only electrons that have this property, as you seem to think: almost everything appears to have it). If you put a charged particle such as an electron inside a nonuniform magnetic field (e.g. inside a Stern-Gerlach apparatus), for example, it will have only two possible values for its magnetic moment thanks to this intrinsic spin, and hence the electron would be deflected by the field in only two possible directions.

http://www-math.mit.edu/~bush/gallery.html

This attributes the lack on interest in nuclear power investment entirely to regulatory and legal issues rather than any intrinsic problem with competing with other power investments in the marketplace.

I would direct interested readers to a very good recent study on the issue of nuclear power: "The Future of Nuclear Power" at http://web.mit.edu/nuclearpower.

Referring to pg. 41 of the study: "under what we consider to be optimistic, but plausible assumptions, nuclear is never less costly than coal."

The fundamental problem is that nuclear power has an intrinsic high capital cost that makes it hard put to compete with other forms of energy that have lower capital costs. This is *not* a function of regulatory delay.

The MIT analysis excludes a couple of factors that makes the barrier to investment even higher. The estimated cost of nuclear power is valid (given that all the optimistic assumptions prove out) over the expected (40 year) life of the plant. But investors want a faster pay-out, the faster the better. Given equal cost power, they will prefer plants that achieve this cost over a shorter time period - i.e. ones that are less capital intensive. So even if nuclear power matches coal in cost or is marginally superior, over the planned plant life, it will still be discriminated against by investors. (Another disincentive that Decker-Mage mentions above is potential legal liability.)

Unless there is some penalty applied to coal generation that limits capacity added, or drives up the cost, nuclear power is not going to complete in a market-driven power business. (This capital cost problem afflicts solar power also.)

Regulatory intervention in the power production industry is going to be required to restrain the growth of CO2-releasing coal power. Carbon taxes are one possibility, requiring carbon capture and sequestration is another.