Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Comments

top

Grand Ayatollah Says High Speed Internet Is "Against Moral Standards"

tibit Re:If the Grand Ayatollah's against it.... (510 comments)

It doesn't matter anyway, since the number for a name/word is counted by adding the letter values (hebrew and greek both have them) together. The number for www is 18, not 666. In ancient times, if you were jewish, and your sweetheart wanted to say in code that he/she loved you, the line would be "I love the person whose number is 140". 140 is your number (K=20, M=40, P=80 in Hebrew). This tradition does in fact carry forward in interesting ways - I distinctly remember that we had a similar system going in the elementary school. Someone came up with value assignments for all letters of the roman alphabet. At some point every literate kid in the building had those assignments memorized. It was a shortlived fad, even though it was good to get the kids doing some addition exercises and decomposition ("decoding") of integers into sums.

yesterday
top

Software Error Caused Soyuz/Galileo Failure

tibit Re:"Programmers" shouldn't write critical software (155 comments)

"Getting rocket software right is difficult precisely because there is no way to do a live test." There is. You do hardware-in-the-loop tests where the inertial and other inputs come from simulators. I have seen testing of a jet engine controller done without an actual jet engine attached to it. There was a beefy server that was simulating the physics of a jet engine, though, and providing sensor readings.

4 days ago
top

3 Congressmen Trying To Tie Up SpaceX

tibit Re:This gave me a chuckle (393 comments)

Ah, I see you've been to Soviet Union, then, comrade. They always did 150% of the norm!

about two weeks ago
top

Tesla Removes Mileage Limits On Drive Unit Warranty Program

tibit Re:So there is a problem... (174 comments)

What kind of cars do they sell in UK, for crying out loud? I'd expect anything from a major manufacturer and not from Detroit to be pretty much worn-in at the 100k mark, and ready to go another 200k at least without needing a new engine nor a new transmission. Heck, I'd expect a manual transmission to easily outlast any automatic (yes, the clutch is a maintenance item).

about two weeks ago
top

Tesla Removes Mileage Limits On Drive Unit Warranty Program

tibit Re:So there is a problem... (174 comments)

Huh? My S80 has 1/4 million miles on it, all engine seals are original, no leaks.

about two weeks ago
top

Swedish Dad Takes Gamer Kids To Warzone

tibit Re:Gettin All Up In Yo Biznis (419 comments)

This seems to be the most insightful thing I've read the whole day today.

about three weeks ago
top

Where are the Flying Cars? (Video; Part Two of Two)

tibit Re:As a private pilot... (66 comments)

No. The guy was a lunatic. Sure, he came up with a bunch of useful stuff, but the wireless charging we have now has nothing to do whatsoever with what Tesla envisioned. It is very unfortunate that the two are denoted using the similar words, because they are far from the same. The wireless charging we have now works like an air gap in a transformer core. That effect was known well before Tesla. OTOH, his wireless energy transfer ideas would have only worked in some alternative universe with different laws of Nature. It was total lunacy.

about three weeks ago
top

Where are the Flying Cars? (Video; Part Two of Two)

tibit Re:As a private pilot... (66 comments)

Quick, somebody clone Nikola Tesla!

I don't want someone, who later in life didn't seem to grasp basic experimental evidence before him, to have anything to do with designing, well, anything.

about three weeks ago
top

3 Congressmen Trying To Tie Up SpaceX

tibit Re:Not So Fast... (393 comments)

Look, if you want so desperately to do something to the payload as long as it's done on time, I'll just go and bash the shit out of it for $1M per paylod, mmkay? I can even use a $50k hammer to do it. What a steal. Cost plus of course.

Now, in the real world, is the "reasonable level of performance" you speak of the same performance USA (United Space Alliance, ULA precursor) had with getting the Shuttles into orbit? Because that was, lest we forget, a major farcical opus every time it didn't happen. But so is space flight, and SpaceX is going in exactly the right direction to change it.

Anyway, so far we don't care about lack of insurance. The damn things get whey they are supposed to. Never mind that I'd like a citation for that lack of insurance of public payloads.

about three weeks ago
top

3 Congressmen Trying To Tie Up SpaceX

tibit Re:Not So Fast... (393 comments)

I keep hearing this nonsense, and I can't help but imagine that it's coming straight from the ULA puppets. Nobody is given any free passes. They are contracted to deliver stuff to orbit, not to build rockets for the government. The safety and reliability standards are of not much use if you're being paid (or not) for service. The only ones hurting if a Falcon blows up are SpaceX and cargo insurers: the former won't get paid, the latter will have to pay up. That's all there's to it.

So far, Falcon 9 hasn't blown up once. You're just repeating the stupid ULA nonsense. Stop it.

about three weeks ago
top

3 Congressmen Trying To Tie Up SpaceX

tibit This gave me a chuckle (393 comments)

"an epidemic of anomalies" ha ha, good one. Falcon 9 had 11/11 primary mission successes on the first 11 flights. That sort of a track record is very, very rare. Space Shuttle did it. What other launcher had the same record? Never mind the overall cost of achieving it. If one adjusts for successes per dollar of development costs, Falcon 9 will have everyone beat for a long, long time, if they keep at it.

about three weeks ago
top

Long-Wave Radar Can Take the Stealth From Stealth Technology

tibit Re:Might cause a re-thinking of the F-35 (275 comments)

TL;DR: F-35 would have been picked up by British radars that came into use towards the end of World War II. So much for stealth. The funniest thing? Everybody who knows about radars has known it since day one. All stealth planes suffer from this problem. Once the wavelength approaches the facet size, the fact that the facet is smooth and "points elsewhere" doesn't matter. It produces what amounts to specular highlights.

about three weeks ago
top

T-Mobile Smartphones Outlast Competitors' Identical Models

tibit Re:No towers in range? (127 comments)

Usually, a terrestrial phone doesn't need to do anything much to "look" for a tower, besides keeping its receiver turned on. Towers emit beacons, and if you don't hear the beacon, there's no point in you sending anything - you won't receive a reply because you don't even hear the tower's beacon.

about a month ago
top

Harvesting Wi-Fi Backscatter To Power Internet of Things Sensors

tibit Re:Lab experiment (138 comments)

s/GSM/GPS/, duh.

about a month ago
top

Harvesting Wi-Fi Backscatter To Power Internet of Things Sensors

tibit Re:Lab experiment (138 comments)

For multiple devices, the GSM-like CDMA would be viable. Each transmitter can use its own Gold code.

about a month ago
top

Harvesting Wi-Fi Backscatter To Power Internet of Things Sensors

tibit Re:Wonderful (138 comments)

The black boxes measure physical acceleration. Sure, they can log the throttle angle, but those two things aren't in a linear relationship, and you can't infer much from the throttle angle other than determining what the driver was trying to do at the time of the crash (WOT, idle, in-between). At the very least the acceleration is a function of RPM and mass air flow. How the latter relates to throttle angle is very engine dependent.

about a month ago

Submissions

top

MRI Magnets Cause Nystagmus

tibit tibit writes  |  more than 2 years ago

tibit writes "In an interesting twist on "it's so old it's new again", Johns Hopkins researchers led by Dale Roberts found what must have been causing much confusion for doctors the world over: strong external magnetic field can stimulate the semicircular canals, causing vertigo and nystagmus (pendular eye motion). It's a textbook case of Lorentz force in action: our angular rate gyros, the semicircular canals in the middle ear, filled with endolymph, have a ionic current flowing across. In magnetic field, the current produces a force that pushes the lymph along the channel, causing stimulation of the cupula — a pressure sensor at the end of the channel. This is interpreted by the brain as rotation of head in space, and causes a nystagmus that's supposed to stabilize the image on the retina. Of course the subject is laying down and not spinning in space, and the mismatch between inertial measurements coming from the ear and real situation causes vertigo."
Link to Original Source

Journals

tibit has no journal entries.

Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>