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Comment: Re: Apply liberal amounts of gloss. (Score 2) 218

by Muad'Dave (#47646359) Attached to: Point-and-Shoot: TrackingPoint's New Linux-Controlled AR-15s

... it would be better if people learned how hard it is to shoot well on distances over 100 meters.

The corollary to this is "don't shoot beyond your abilities." If you know you're inexperienced or a poor shot while under the influence of 'buck fever', don't try the long shots in the first place. These days there are plenty of does* that will basically walk right up to you for a clean, humane kill.

*Where I live, they've basically declared open season on deer - 6 a year, three of which must be anterless, the whole 1.5 month firearms season is either-sex, plus all the bonus deer tags you can buy.

Comment: Re:So.. what? (Score 1) 255

by Muad'Dave (#47630129) Attached to: TEPCO: Nearly All Nuclear Fuel Melted At Fukushima No. 3 Reactor

Some nuclear plants can be ramped up and down ...

Some designs provide automatic load-following - from this MSR PDF:

... as the reactor temperature rises, the reactivity decreases. The reactor thus automatically reduces its activity if it overheats. Conversely, if more power is required of the reactor, more heat is drawn out. The returning colder salt increases reactivity and power levels resulting in automatic load following.

MSRs can also be manually throttled quickly due to the absence of the neutron poison problem.

Comment: Re:New? Hardly! (Score 1) 138

by Muad'Dave (#47613119) Attached to: Harvesting Wi-Fi Backscatter To Power Internet of Things Sensors

I absolutely agree - that's why I opined that harvesting power form other, higher power external sources might be more effective.

I've done a fair bit of weak signal work on the 30m band. I once transmitted with 100mW of power using the WSPR mode from Richmond Va and a station in New Zealand received and correctly decoded it. That's a lot of km/W ! Here's a map of current activity.

Comment: Re:New? Hardly! (Score 1) 138

by Muad'Dave (#47606881) Attached to: Harvesting Wi-Fi Backscatter To Power Internet of Things Sensors

I never said it was efficient, just not novel. I understand the RFID technology pretty well - we did have tags that would read from 10m or so with about 4W EIRP (1W power + 6dBi antenna). The other thing that you run into is that no one wants a tag with an antenna anywhere near the length required to be efficient. A 1/2 wavelength dipole at 915MHz is still 16cm overall.

If this were developed years ago and if you were to rely on transmitters outside the home, they'd use the pager transmitters at 450/460 MHz to power things. These were beastly strong and transmitted 24x7. Today cell signals would be a good choice. I haven't done the 1/r^2 math, but I bet the proximity of the WiFi will beat the power density of just about any external-to-the-home transmitter.

Comment: Re:Waste disposal not included (Score 1) 343

I can't fathom how you can call a successful run of a brand-spanking-new technology a failure. The technology WORKED. It ran as expected with no issues.
I counter that the existing PWR designs are dangerously flawed, and should never have seen the light of day in power-generating reactors. Thanks, Rickover!

Comment: New? Hardly! (Score 1) 138

by Muad'Dave (#47605925) Attached to: Harvesting Wi-Fi Backscatter To Power Internet of Things Sensors

Take a look at how RFID chips have worked since day one - they use the incident RF to power the chip that then back-modulates the transmitted signal. In other words, the RFID tag actively modulates the load impedance it places on the antenna causing changes in the radar cross-section of the tag. The tag transceiver sees these variations in cross section as data from the tag.

Comment: Re:Waste disposal not included (Score 1) 343

Urging moving to an even more accident prone and unstable technology is irresponsible.

Remember, we've had 40+ years of experience with PWR reactors - of course there are gotchas in any new (or revived, in the case of MSRs) technology. Those 40 years of operation have, I think, made safety officers complacent, much like the managers at NASA wrt to the shuttle. They're blind to the inherent design issues in PWRs that make them less resistant to faults (much less room for errors - fewer passive safety features, too many manual safety features required).

You also have to take into account the severity of the aftermath of an accident. A primary loop leak in a PWR - disaster. You have to scram the reactor, hope the aux pumps work, deal with the steam blowoff, cool the core until the daughter products cool off, etc, and then deal with fixing a pipe made to withstand 3000+ psi. MUCH more room for a ecological and/or economic disaster.

A primary loop leak in a LFTR - turn off the pumps, dump the coolant/fuel in 'the pit' or let it freeze, get the 'bots in there and fix a pipe made to withstand 100 psi or less.

Given the passive safety features of molten salt/molten fuel reactors such as the LFTR (large negative void coefficient, no phase changes so no need for a huge containment structure, fuel/coolant will 'freeze' on shutdown and remain subcritical, etc) along with their operation at essentially zero primary loop pressure, I'd say their safety record could be much better than any of the existing PWR/BWR designs by an order of magnitude. All we have to do to get there is build a few small ones, work out the kinks, and get going!

Comment: Re:Waste disposal not included (Score 1) 343

The Hamm-Uentrop accident was the result of a stuck fuel 'pebble', not something related to it being a breeder reactor or even a gas-cooled reactor.

Which failed molten salt experiment are you referring to, this one? I would not characterize it as a failure at all - if fact it was a rousing success, even if there were a few lessons learned along the way that influenced the MSR design going forward. "Much of the high cost [of decommissioning] was caused by the unpleasant surprise of fluorine and uranium hexafluoride evolution from cold fuel salt in storage that ORNL did not defuel and store correctly, but this has now been taken into consideration in MSR design." [emphasis mine]

Why do we want intelligent terminals when there are so many stupid users?