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Comment: Re:We have already figured most of this out. (Score 3, Interesting) 363

by bored_engineer (#49473283) Attached to: Can Civilization Reboot Without Fossil Fuels?

Probably not*. The "old asphalt roads" are 90-96% aggregate (rocks). The asphalt is really just a flexible binder for the harder stuff. Also, the lighter volatiles have long since evaporated from the asphalt cement, so it won't readily light. Come to think about it, the asphalt cement is, cut with water, emulsifiers and other additives to improve application and durability.

*I did some calculation to determine the heat content of asphalt concrete roads as compared to wood, and I've decided that both may be useful, depending on context:

  1. 1. Decent hardwood (think birch, not hickory) has a comparable Btu content as asphalt concrete:
    1. --Seasoned Birch: 6.95 kBtu/lb, 162.5 kBtu/ft^3 (these are based on cord density, not wood density);
    2. --Old Asphalt Road: 8.82 kBtu/lb, 64.9 kBtu/ft^3 (based on in-place density, 5% cement content & 30% additive content).
  2. 2. I will guess that wood will release the heat more quickly, while the aggregate in asphalt concrete will store heat and release it slowly over time.
  3. 3. Wood and "old roads" will require approximately the same handling. The wood needs to be cut, split and stored while the asphalt needs to be broken up, then the (potentially useful) aggregate will need to be (re)moved.
  4. 4. The asphalt cement will need an existing hot fire to start. The ignition temperature of asphalt is ~900F, so the entire mass including the aggregate will will absorb a great deal of heat before it starts contributing anything.
  5. 5. profit?

I set out to demonstrate that your comment wasn't very useful, but it looks like old asphalt roads may, in fact, be useful for keeping warm, with the caveat that some other material will be needed to start (and maintain) an asphalt concrete fire.

Comment: Re:Real porpose of the road (Score 1) 226

by bored_engineer (#49348573) Attached to: Russian Official Proposes Road That Could Connect London To NYC

Nobody drives between Los Angeles and Anchorage, except as a road trip just to say they did it.

I've driven between Los Angeles and Fairbanks three times, plus three other trips including one from Austin, TX to Anchorage, AK. Not a single one of the trips was a tourist jaunt. There's also freight that comes up the Alaska Highway.

Comment: Re:moonquakes (Score 1) 124

by bored_engineer (#49302349) Attached to: Giant Lava Tubes Possible On the Moon

I didnt see ay mention of moonquakes.

Did you read the paper? They didn't model any seismic activity, nor did they model any confining stresses. As such, their:

failure values are slightly conservative (i.e. low in magnitude) in order to compensate for [their] not modeling other stress sources such as seismic shaking from meteorite bombardment.

The point of the exercise was to theoretically confirm that large lava tubes can exist because:

Recent in-depth analysis of lunar gravity data from the Gravity Recovery And Interior Laboratory (GRAIL) spacecraft has suggested the possibility of lava tubes on the Moon with diameters in excess of 1 km.

Comment: Re:My LED bulb didn't last! (Score 1) 328

I've been using CFLs and flourescents for 20 years, but continued to use incandescents in a few places because my Mrs. didn't approve. I've managed to win her over with LEDs, though. For the last few days, I've been contemplating whether to replace the vanity light with bulbs similar to those mentioned in the article, or to purchase an LED fixture.

Comment: Re:Becasue... the children! (Score 1) 190

by bored_engineer (#49250787) Attached to: Powdered Alcohol Approved By Feds, Banned By States

Alaska has local option for alcohol imports*. Many of the villages ban it, but many still see a steady flow of booze. It would be impossible to control alcohol movement into villages if it could be smuggled in small sachets.

I'm not trying to run down that Alaska is dangerous, as I've certainly known people maimed or killed by cold or bears.

*For many of the villages, anything they don't make or harvest locally is brought in by barge, plane or barter with other villages 10s of miles away by trails. Much of Alaska has no connection to the road network.

Comment: A load of waffle? (Score 2) 374

by bored_engineer (#49131623) Attached to: The Groups Behind Making Distributed Solar Power Harder To Adopt
I can't speak to your utility company, but each of the two electricity utilities that I've purchased service from have charged me a monthly fee for the privilege of being connected to its grid. Nor did that utility company pay to connect my house to that grid: I did. Even if I generate an excess, the utility is still compensated for the maintenance of the grid.

Comment: Re:Old news. (Score 1) 285

by bored_engineer (#48660429) Attached to: Study: Red Light Cameras Don't Improve Safety

Until four years ago, I worked in Los Angeles as a traffic engineer. The ATSAC system is used on more than 4,000 intersections, is interconnected, and makes adjustments to signal timing either manually or automatically. There aren't cameras at all of the monitored intersections, but you don't need cameras to measure traffic volumes and speed, they're just an additional tool.

Further, the systems that use cameras for vehicle detection are falling out of favor. There are too many conditions, such as rain, snow, fog and bright sunshine that can befuddle the systems and cause them to fall back to pre-set timing rather than relying on vehicle detection. Where inductive loops aren't used, radar is proving to be more reliable than cameras.

Even where there's no interconnection, most intersections have controllers that are considerably more sophisticated than simple timers.

Comment: Re:Study financed by (Score 1) 285

by bored_engineer (#48654723) Attached to: Study: Red Light Cameras Don't Improve Safety

Three seconds is the minimum duration as per federal law.

What gave you that impression? Signal timing is determined by an equation, but may have some minimum defined by local or state law, or in a design manual.

At 25 MPH with no grade, depending on law or policy, it may be perfectly permissible to have a 2.8s interval, though it's common in practice to round that to a minimum 3s. Here's the equation from the 1999 ITE handbook:
Y=t + 1.467v/2(a+32g), where
t=perception-reaction time, typically assumed to be 1 s,
v=speed in MPH (ITE recommends using the 85th percentile speed, but many agencies use the posted speed.),
a=deceleration rate, assumed to be 10 ft/sec^2,
If you want to read more, NCHRP report 731details recommended guidelines, and provides some history for the recommendations.

We don't know one millionth of one percent about anything.