Follow Slashdot blog updates by subscribing to our blog RSS feed


Forgot your password?

Comment Re:Aeroelastic flutter (Score 1) 168

Here's an older paper:

The distinction is drawn at the end of part III. Seems to me to be pure semantics. If the bridge were driven to flutter at a self-resonant frequency then yes, it was a resonant phenomenon. Does causing a wine glass to emit a tone by running your finger around the rim constitute a resonant phenomenon? The variation of the driving force being at the resonant frequency is caused by the wine glass vibrating at that frequency already, as was the variation on the torsional forces on the bridge being caused by the bridge already vibrating.

Comment Re:Aeroelastic flutter (Score 2) 168

Resonance is :
"a phenomenon that occurs when a vibrating system or external force drives another system to oscillate with greater amplitude at a specific preferential frequency."

Exactly. Notice the external force part. The external force needs to DRIVE the motion at a specific frequency. THAT is resonance.

The original sentence might be slightly ambiguous but it doesn't explicitly state that the external force needs to drive the motion at the specific frequency. It just says there needs to be an external force, and that it drives another system to oscillate at a specific frequency. I don't know where the sentence came from but I'm curious as to whether flutter is a resonant phenomenon or not.

Comment Re:Be careful of the term "terrorist attack" (Score 1) 737

They also hate calling something a "terrorist attack" if there isn't a pre-announced political message for the reasons behind the attack.

Well isn't that pretty much the definition of terrorism? An attack designed to instil fear (terror) of potential future attacks against which there is no real defense?

If some random nutjob takes down a plane full of innocents, even in the name of whatever deity and for hate-filled reasons, it's not terrorism unless the reason is clearly advertised and poses a future threat that causes fear.

PS: 'Terror', however, means fear. "War on Terror" is a ridiculous mangling of the meaning of words.

Comment Obvious? (Score 1) 274

I thought this was common knowledge, or maybe the study is confirming what was long suspected?

Germans have a reputation for being precise, their language is very precise, so it would seem to follow that if one is 'thinking in german' one has to think at a level of precision which far exceeds, say, chinese, which as a spoken language is very simple (tonal complications notwithstanding). Then again written chinese has immense potential for deep poetic meaning due to the recurring use of similar tones and similar partial-characters, which phonetically-written or alphabet-written languages simply cannot have.

Japanese is built with less precision in specification but a minefield when it comes to respect levels. In Japanese you have to *think* in a manner that respects your view of everyone's relationship to each other in terms of seniority, superiority, deference, familiarity etc.


Comment Price and Pretty! I bought loads. (Score 1) 328

I ordered a whole load from Aliexpress for around $4 each. Given the expected life of them and the efficiency I thought that was a pretty good pricepoint.

Plus they really are pretty to look at, and dimmable! (you can specify dimmable or otherwise, voltage, and fitting type)

So far the ones I got in 4W and 6W configurations emit light comparable to 40W and 60W bulbs imho, They run cool, barely getting warm after long use. The colour is very nice, much better than the old style LEDs, i.e. without the blue haze. They dim nicely although without changing colour temperature,

The model I got doesn't have a smoothing capacitor though, so they flicker noticeably if you're moving around. I know there are better models but so far it's hard to tell which is which as there are many different sellers on Aliexpress.

Comment Re:This ex-Swatch guy doesn't have a clue (Score 1) 389

I'll admit I'm something of a watch 'enthusiast'. Now, there are a couple of reasons I probably won't buy the iWatch right away, but I'd consider it down the line, especially as more apps get made. It looks quite useful. Now if I find my self wearing the iWatch all the time I'm less likely to want to plunk down for another mechanical piece.

Comment Re:This ex-Swatch guy doesn't have a clue (Score 1) 389

>The Apple watch presents no threat to such Swiss watches, any more than a Tesla
>car presents a threat to Porsche.

The fact that the Tesla Model S 85D is about the same price, but is actually quicker than a porsche, tells me Tesla is capable of being a real threat to Porsche, in some model categories now, and potentially all model categories in the near future.

>Me, I think the Apple watch is interesting but it is ten times more expensive than it should be

So are swiss 'luxury' watches. The people who plonk down $5k on a mechanical watch over a quartz aren't going to blink at $349 for a status symbol that's also very useful. Let alone those walking round with $30k timepieces.

>and is not waterproof, and these two facts mean I will never ever own one.

That is a big issue for me, as is the 18h battery life. What good is having your payment system and your hotel key built into the watch if the watch is dead by the time you pay your bill for dinner or return to the hotel at night?

The other issue is planned obsolescence. I can't imagine the level of douchebaggery required to plonk down $10k on a piece of tech that will be obsolete in a year's time. Apple has to at least maintain the form factor and offer upgrades down the line, which so far they haven't stated will be possible.

Slashdot Top Deals

If you are smart enough to know that you're not smart enough to be an Engineer, then you're in Business.