Comment Would be nice... (Score 1) 70
...if this Slashvertisement would tell us what the hell JIRA is!
...if this Slashvertisement would tell us what the hell JIRA is!
A few facts that, for some reason, haven't been stated in this discussion:
1. EMI/RFI--AC systems radiate a lot of noise. Some come from lines discharging through a natural diode and the rest is the lower frequency 50/60 cycle AC and its harmonics. Even discounting the EMI-sensitive people out there (whether you believe them or not), there's no question that it affects receivers and some other electronics, and occasionally magnetics like a credit card. DC normally shouldn't have this problem.
2. Outside of motors and other heavy loads, most loads outside of factories and such are light loads, thus 48-60 volts with light gauge wiring might be sufficient for short (household or small business) distances.
3. A *BIG* safety issue no one has talked about is the increasing danger with voltage and going DC. This is a 2 pronged problem:
A. with AC the voltage goes down to zero every half-cycle, which is why switches can be made relatively simple under that 400 volts mentioned. But this disappears at DC and an arc or spark that fires WILL *STAY* FIRED as long as the power remains applied! I learned this at a GM discussion for mechanics when they were discussing the (new then) Chevy EV1 and its competition from Honda and Toyota when they talked about why they chose 36 volts for that car: its the highest voltage that won't carry a stable arc. The speaker pointed out that a pin hole, which would self-heal and not normally cause a problem on normal 12 volt circuit, would cause a self-maintaining arc at 48 volts if the hole came into contact with the frame. Of course, we all know what happened: the car failed due to lack of range (using lead acid!) and power (ohmic loss). But the safety issues remain, even on modern cars with high voltage DC battery packs, even though they seem to be solved...
B. Above 400 volts or so flash danger becomes a real threat, as lots of Youtube videos attest. Going to DC this could be a lot worse, I would think, as the arcs wouldn't self-extinguish. Combine this with heating inside the cells due to internal resistance and you could see a big BOOM!
As it currently stands, commercial buildings often have 277V lighting circuits (this is in the US) because it involves installing less copper in the ceilings.
Perhaps that was the reason in the old days, but more likely (especially for newer construction) it's because this is the voltage you get between a leg and neutral from a 3-phase wye transformer at 480 volts leg to leg AKA 480/277Y. Here in Phoenix you see this a lot at the bigger retailers where that 480 volts is used to drive the freezers and general building refrigeration needed in summer. It makes sense, from a safety standpoint, to use the lower 277 volts where the power draw doesn't necessitate a higher voltage. (Of course, that doesn't mean I'm not wrong here, and your Cu cost argument is totally sound, especially these days!)
The lower voltage version (here in NA) is 208/120Y and is VERY common in certain places such as the motel where I work where 120v is needed most, but 3 phase is needed by a few things (in our case, the washing machines and outdoor sign). The A/C units are wired to accept the lower 208 volts instead of 240 and we buy them that way from the retailer (they can still be rewired to 240 if necessary).
https://www.youtube.com/watch?...
OMFG, does the evil Empire really need to strike again?!?
I still have my AT&T V3xx, and the charge port is a very standard mini-USB rather than the micro-USB that's standard now; however, it's still a USB device and will talk to your computer just fine. Oh, and this particular device was one of the first UMTS phones so it will still work when GSM is switched off. (I'm worried about my Nokia N900 in this regard since it only does UMTS on Band 4 AKA AWS 1.7/2.1 GHz.)
As for the tools, I looked a couple of years ago, but not that hard, so not sure. I do know the open source tools that used to work with it haven't been maintained since the smartphone explosion (which also corresponded to the recession, so a 1-2 punch).
Finally, a word to the wise: when the Batteries Plus guy says that you need to knock out a piece of plastic so his battery will fit, turn around and walk out. Since I punched that that tiny piece of plastic, the battery will not stay in and the door does not apply enough pressure to keep it in there. The case does, but only barely, and the back of the phone flies apart if I drop it. (On the plus side, the case works: the phone is still fine after all these years!)
4) NASA does some really great stuff that benefits every american citizen immensely. Like your 10 day weather forecasts? LIke your GPS navigation. Thank NASA.
Ah, no:
Weather? That's NOAA, not NASA. Yes, 4 letters and starts with "N" and they both do stuff in space, but that's about the limit of similarity. Oh, and the US DOD has their own weather bureau as well--what better way to waste lots of money than duplicating the functions of a "civilian" agency?
GPS? That's the US Air Force, just like the X-37B, not NASA. The fact that the US Military Industrial Complex controls GPS is one of the driving reasons behind Galileo (and, to some extent, other GNSS's), despite Galileo being built by the European Military Industrial Complex but assumably under "civilian" control. Suuure...
Have to play Devil's Advocate here, but it could also be for development of defense AGAINST weapons. Think about it: China (and the US, I believe) has already blown a satellite in LEO out of the sky. The 60 Minutes piece on the weaponization of space (and especially AGAINST space) is not just over-hyped (for a change), but a real threat. If someone can make a weapon that can take out satellites in MEO (GPS, GLONASS, Beidou, Galileo, etc) and GEO (both geo-sync and sun-sync), there will be a real problem. Of course, this isn't to take away from the denial of near-space around the Earth altogether due to the creation of massive amounts of debris, and the creation of a maneuvering system that uses much smaller amounts of fuel than before could be the prelude to "garbage trucks" in space to clean things up.
In fact, it just occurred to me that the X-37B may be the most visible sign of a new arms race that's mostly taking place behind the scenes because China in particular is so secretive (much more than the old Soviet Union).
WE SLEEP
Pretty sure "blew up and failed safe" is an oxymoron.
Not at all, rockets being launched into space (or as ICBMs) are blown up with explosives carried on board in order to insure the safety of those on the ground. In this case, NOT blowing up and being out of control means a missile is about to hit something and make a big boom on the ground!
Oh, and transformers blowing up, yes they are spectacular--haven't been there myself, but I've seen the aftermath. Might have something to do with up to hundreds of gallons of oil inside to cool the thing combined with banning of PCBs to keep that oil from catching fire in these situations.
In any case: tens to hundreds of kilovolts (near a megavolt in the highest voltage systems) combined with thousands of amperes is a whole lot of power waiting to burst out in a gigantic arc that will set fire or melt everything in a spectacular way! Oh, and it would probably generate X-rays, so I guess you would get some ionizing radiation, at least until the safety tripped.
I have personally encountered AUTOMOTIVE drivers weaving side to side, tailgating and making sudden lane changes (the worst one was also in heavy rain just as I was about to pass a AUTOMOBILE) - and I don't even drive that much. I blame all that activity on drivers who either don't pay attention, are possibly sleep deprived and/or are trying to make some arbitrary (and possibly illegally imposed) mileage requirement. If that can be eliminated then the roads will be a safer place to be.
There, fixed that for you. Your entire argument can be applied to cars, pickups, buses, even bikes. Your bias is showing.
Signed, a CDL holder.
Someone should make a wireless version
What I was thinking, too. Like they have on Android (built-in to Lollipop, add-in on older versions) and iOS where the thing will lock (possibly scream) when you and your "security dongle" (which can be anything) walk away from each other.
For this kind of laptop security, I'm thinking a Class-3 bluetooth dongle (1 meter range) or even an IR blaster might work.
Another thing that hit me looking at the code: invoking a gentle "shutdown -h now" may not be fast enough. If you're this paranoid, perhaps you should just force immediate power off (crash dirty with no flushing) and take your chances.
Killing cancer cells is easy. Killing cancer cells without also destroying everything else is a very hard problem to solve. If this protein can force cancer cells back into healthy cells (or at least self-destruct) WITHOUT negatively affecting healthy tissues then this would be significant.
Exactly! This is precisely why this is not a small step, and hopefully will lead to similar research and treatments on other cancers.
Another way to put the significance of this is a magic chemical or drug that turns zombies back into normal people. (Ok, cancer is the opposite of a zombie, but you get the point.)
"I'm a time traveller. I point and laugh at archaeologists!" (TV: Silence in the Library)
"Whiskey is for drinking and water is for fighting over."
...lack of familiarity with the terms used in RF engineering.
Got beaten to the punch here. I was about to submit this confusing quote from TFA:
the two-wire ribbons used during televisionâ(TM)s first few decades to send RF signals from rooftop VHF antennas to television sets without any loss. The electric RF current in the two conductors flow in opposite directions and have opposite phase. Because of the translational symmetry (the two conductors are parallel) the radiation fields cancel each other out, so there is no net radiation into space.
Took a few reads before I finally figured out they were referring to 300-ohm twin lead...
[digression]Captcha for this is "shudders". Indeed...[/digression]
Memory fault - where am I?