Fountain Advice

So, if I were to design another fountain, how would I do it differently? (This is for you, Diane.)

• 8 inch flow straighteners. There is no sense in messing around with Reynold's numbers. You want it to be around 2000, and that means you need huge internal cross section. 8 inch PVC is actually reasonably easy to get. SCP in Santa Clara has it and all the fittings you need.
  
• Design gimballed nozzles from the beginning. Trying to get this right with careful assembly just did not work, the tolerances are far too tight. I think it can be done with screws between the gimballing nozzle and the glued-in support, so that you could adjust the angle after building it.
  
• Rebar connecting the inside and outside rebar curtains. We have a crack all the way around our hot tub which I'm sure is going to make it's way through the tile some day.
• I would build all the fountain jets to a fixture, rather than just half of them. The fixture worked really well and would have worked even better if I'd designed it to be independent of swelling due to moisture. This can be done -- all the surfaces that locate plumbing have to be on radial lines to the center.
  
• Make the fixture locate a center #4 rebar spike, and drive the center spike at least 18" into the ground, and leave it in place while shooting the gunite. This will give the gunite crews something to locate off when they are drawing their circles. One problem that we had was that we kept re-finding the center of the hot tub, and as a result the circles for the plumbing and the circles for the tile and gunite are not concentric.
  
• I would have the guys doing the gunite get the gunite surface level and ready for tiling. We spent a lot of time levelling that gunite out.

There were also a couple of things we've learned about the tiling, which would have saved us a bunch of time had we known it a year ago.

The glass tile is 1/4" thick, and can be set with just 1/8" of thinset, but this isn't the stackup you want. There are two problems: the thinset shrinks, a lot, as it cures, and this tends to bend and eventually break the tile. Also, the plaster guys want to be 5/8" thick, not 3/8" thick. They can feather down to 3/8", but they don't like it, as explained below.

So, you want to put down on the gunite 1/4" of some kind of low-shrinkage mortar, and screed it so that it is flat. This is the stuff that is going to take out all the uneveness in the wall. However, you can't be sure it's going to stick really well to the gunite. So, the stackup we used under the last mosaics ended up being:

• 2 coats of Hydroban, sticking out at least 1" past any of the rest of the stack. This forms a structural watertight barrier. The principle issue being protected against is water leaking through the cold joint between the plaster and the tile, and then leaking into the gunite from there. Hydroban is expensive, but only comes in 5 gallon buckets, which is enough to cover a ridiculously large area. I think they are trying to make sure you use a lot.
  
• Some thinset, as thin as it can be, to adhere the mason mix to the hydroban.
• 1/4" mason mix (either "deck mud" for the tile on the pool bottom, or "fat mud" for the tile on the walls), screed to be dead flat.
• After that all sets up (ideally about 4 hours so it gets a chance to shrink, but isn't fully hard, think about covering it with plastic to keep the water in), a super-thin layer of thinset on both the mason mix and the back of the tile.
• Blue tape out the wazoo for anything on a wall.
  
• Then cut the stiff but not yet really hard mason mix away from the edge of the tile. We never let the mason mix set up so hard that it was sticking to the hydroban tightly, so this was pretty easy to do without nicking the hydroban.
  

On our dam wall, we had to build up the wall top with an angle to hold our teflon strip. The easy way to do this would have been to just do it with wall mud, screed with one of those adjustable angle things running along a strip screwed to the side of the wall.

Now back to the reason the plaster guys want to put down 5/8" material. For any kind of exposed aggregate surface, they shoot the mix, then trowel it. The troweling is usually done (on a smooth plaster finish) to bring the "cream" to the surface, but for an exposed aggregate surface they are using the side effect, which is to compact the aggregate below the surface. Then, when they wash away the surface, they expose more tightly-packed aggregate. Since cement but not aggregate will erode from chlorine attack and mechanical erosion, it's better to have a surface which has more aggregate.

The reason they don't simply mix more aggregate into the mix before they shoot it on the wall is that, when the aggregate and sand grains are randomly oriented, they simply can't pack densely enough. If you subtract sand/cement/water, you don't end up with more aggregate in the as-shot mix, you end up with more air. And air is no good because the plaster has to be watertight (and dense and strong). Once the mix is on the wall, they work it with the trowels, which helps settle the aggregate and sand grains together more tightly. This is why the quality of an exposed aggregate surface has a lot to do with the skill of the guys doing it.

In looking at the samples provided, it's clear to me that most folks aren't actually attempting to get a maximum packing of aggregate, and I don't understand why. Why don't they mix larger and smaller aggregate together, so that the small aggregate packs in the spaces between the larger aggregate?

Pocohontas Retold

Spoiler alert: I discuss the movie Avatar below.

When I read the Pocohontas story to my kids (we have the Disney version), we usually have a little discussion when we get to the page where Pocohontas attempts to dissuade her father (the local Indian chief) from starting a war with the settlers. The kids are interested in the idea that both people are trying to do the right thing, but they have completely different ideas about what the right thing is.

For those of you not familiar with the story, Pocohontas has fallen in love with a mercenary on the voyage (John Smith), and the two of them want to establish peace between the settlers and the natives. The book suggests that peace involves the settlers staying in North America. Powhatan, her father, is assembling a war party to drive the settlers away.

We can look back in history to better understand who was "right".

• As the book makes clear, a war between the settlers and the Indians is going to lead to many Indian casualties, since the settlers have guns and the Indians do not. Furthermore, most of the settlers are not intending to do harm to the Indians, as they've been told they are settling land that has no ownership yet. Pocohontas' efforts end up saving many well-intentioned people's lives.
• These same settlers would probably understand that, had they landed anywhere in England and built a village where they landed, they would be summarily evicted by whomever owned the land they were on. The racism here is lightly touched on in the book, but it's helpful because it's pretty easy for the kids to see how convenient it is for the settlers to suppose that nobody in North America owns anything yet.
  
• I usually tell the kids what little I know of the Mauri, the indigenous people of New Zealand. As I understand it, they immediately made war with white folks who arrived. I suspect that the Mauri were territorial in a way that worked better with the White conception of property, and because of that Mauri today have a significant representation in the New Zealand constitution and legislature, and own very large amounts of New Zealand's real estate. I expect many Native Americans would prefer the Mauri outcome to their own.

I recently went to see Avatar. It's basically the Pocohontas story, but the ending has changed and the natives switch from the Pocohontas to the Mauri approach. The change comes from two differences:

1. The Na'vi are territorial. They have a few specific high-value trees. My understanding is that most of the North American natives had a much less specific sense of property.
2. The movie has the natives resisting under human leadership, which is interesting to think about. It seems a bit condescending (especially the bit where the human, after 3 months of training, is outperforming the best of the natives), but historically North American natives really did not grasp the nature of the European threat fast enough to organize a massive resistance in time, and it seems at least possible that a charismatic European might have communicated the continent-level consequences of the European idea of property to enough of them to organize a resistance.
   

Although the movie doesn't make it clear enough, guns are a big advantage, but a multi-year supply line is an even bigger disadvantage. Although some of the dialog is a bit trite, I think the story is probably going to be a useful place to start interesting discussions. Hopefully they'll have some story books out at some point, because the PG-13 movie is far too violent for my kids to watch.

I once asked a friend who is a lawyer if all property rights, at least in North America, trace back to peace treaties of some kind, or if some (particular the French claim to the center of the continent that was then sold as the Louisiana Purchase) are based on bald assertions of authority without even a war. I never did get a decent answer.

If, in reading this post, anyone is wondering if I'm willing to cede my house to a Native American, the answer is no.

Powered Roadways

If it weren't for the battery problem, an electric vehicle could be a fairly reasonable vehicle today: electric motors are powerful, small, and cheap enough, etc. There are two parts to the battery problem, getting enough power and storing enough energy. Both can be solved by delivering power to the EV from the road. This has been considered many times before, and there are electric street cars that do it in Bordeaux.

The usual idea, however, is very expensive because

• most sections of roadway or railway see little traffic and so the benefit of the high-cost infrastructure is spread over few vehicles.
• the third rail power delivery system is made safe by expensive grade separations, fences, or electronic switching
• the vehicles are very specialized and aren't built in large numbers.

So, to the extent that I'm advocating a new idea, it is... electrify urban highways. By which I mean, install a pair of metal strips flush against the paving in one of the lanes, such that ordinary cars aren't affected, but electric cars can lower a suitable pickup onto the strips and receive a few dozen kilowatts. Both the power and the energy storage demands on an electric vehicle's battery are dominated by the demands of highway operation.

Urban freeways are quite unusual as roads go.

• They see quite a lot of traffic: The San Francisco Bay Bridge moves 270,000 vehicles a day across 10 lanes = 1 vehicle every 3.2 seconds over a 24-hour average.
• They see quite a lot of the traffic: 24% of all traffic is on interstate highways, and I'll guess that most of that is on urban interstate highways.
  
• They are short: in the entire US, there are just 15,300 miles of interstate highway in urban areas (same link)
  
• They already have limited access. The safety hazards of a high-voltage electrical system out on the road are relatively minor compared to the existing vehicles using the roadway.
  

I don't have sources to verify the following claim, but I'm fairly sure that in many urban markets, most trips over 10 miles include some freeway. So, if the freeways in your urban area (e.g. Los Angeles or the Bay Area, or both) were electrified, you could make trips anywhere in that area in an electric car with a battery range of just 10 miles.

And, if all we want is 10 miles of range, with no need to deliver dozens of horsepower for minutes on end, existing battery technology is good enough.

The usual counterargument to big infrastructure is that it costs too much. However, electrifying freeways does not because the freeways are just not that big. Consider the Bay Area:

• 300 miles of freeway
• 7 million cars

If, over 10 years, we got to 10% of the cars being EVs with electric pickups, that would be 700,000 EVs, or, one for every 26 inches of freeway. Can 26 inches of roadway be upgraded for less than the cost of equipping an EV with a huge battery? Definitely.

There are many schemes for electrifying roadways, and some are quite complex. Although a simple pair of flush steel rails at 1000V is probably a reasonable implementation, it might be easier to sell to the public if the rails were safe enough to be touched by hand. This too is possible.

Imagine each rail is a hollow box, insulated on three sides, but with a nonmagnetic and top surface. Inside the box is a lightweight, magnetic, conductive cable (probably aluminum and steel), with a small gap between it and the underside of the top surface. The conductive top surface is broken at short regular intervals by an insulator. The bottom of the rail is probably a large conductor for moving electricity thousands of feet.

Without a magnet, the top surface is not electrified, and you can place your hand on it safely. The car's pickup would have a magnet which would ride on the strip, picking up the lightweight inner cable slightly, so that it contacts the top surface and conducts to the car.

Other variations would have a magnetic top surface with a flux gap, such that flux going from one side to the other shorts through the cable and picks it up that way.

System Design for Martha

I need to buy a new computer for Martha.

• Must drive a flat panel display
• Must accept data from a FireWire miniDV camera
• Must have a DVD burner
  
• We have an ancient parallel-port printer.... which would be nice to use.
  

I could buy a Mac Mini. The Mac Mini has the FireWire interface and DVD burner. However, it will never work with that printer (a replacement will cost $150). The graphics would be much better than any mini-ITX integrated graphics I'd get. We'd get the 2.53 GHz, 4 GB memory, 350 GB version, $830. A VMware executive will cost another $70. The whole thing will come in a nice little case and make very little noise, and I will have even less idea how the software works than I do with the PC.

Or, I could build a PC. I'd get a 3.16 GHz Intel E8500, 8GB memory, 500 GB hard drive. I can get a FireWire card and a DVD burner, and a motherboard that sports a parallel port. Martha will be happy that I didn't make her figure out a Mac (more to the point, how to run PC-only software under VMware on the Mac). Vista will almost certainly never work with the printer, and so I'll still have to get a replacement anyway (a wash at $150). Even crammed into a mini-ITX case (with some risk it will not all fit in the case), it'll cost $875. The Mini idles at 14 watts, and any PC I build will idle at 35 watts. The 20 watt difference, over 5 years of 24/7, costs an extra $350.

Update: Since Martha figures she's going to be stuck with the sysadmin, she opted for the PC, to avoid learning about VMware, Boot Camp, or any other virtualization. If we could order the Mac Mini with Windows preinstalled under a supervisor, such that I could have told Martha that she could simply install any Windows programs or drivers, then she probably would have gone for that. Oh well.

Engineering is Plumbing

http://credentiality2.blogspot.com/2009/01/engineering-is-plumbing-not-math.html

99% of what I do is plumbing.

-Iain

Quick pool status

Patio around the pool is mostly in. Hopefully today they will finish off the corner around the pump vault.

Saturday I had hoped to install the last of the tile mosaics, but instead I found the remaining big Orca cracked in the center, and the north side dolphins had cracked as well. We cut them all off the wall and will reinstall the lot next weekend.

The tilework around the hot tub was fairly tricky. Here's an example of a three-way miter. The tile guys kept looking at me like I was cuckoo. As I explained, you cut it by cutting each of the three two-way miters. It's actually pretty straightforward if you just do it.

The hot tub as a whole. In the background, you can see the breaching Humpback mosaic, along with a portion of the Orca mosaic. The Orcas are the ones that have been giving me so much trouble.

Chuck DeVore nails it

Relative Risk: Global Warming and Imported Fossil Fuels vs Nuclear Power

It's from last year, but Representative DeVore perfectly summarizes the environmental aspirations and political logjam in California, and points out that a voter initiative is possibly the only way to cut through the logjam.

Anniversary of Lezak's Wild Ride

For the first anniversary of Jason Lezak's incredible come-from-behind finish in the Men's 4x100m freestyle relay, NBC has full-race underwater coverage of the race: http://www.nbcolympics.com/video/player.html?assetid=0812_hd_mul_au_ce493&channelcode=sportsw (Watch the link in Firefox, because it doesn't work in Chrome.)

I've written about this incredible race before, but this footage shows in more detail some of what was going on during the race. Although the Australians were doing well at the beginning, by the last lap it boils down to the French and the Americans. America's Lezak takes 29 strokes on the way out, versus France's Bernard Alain, who takes 32. Not much difference, although it is already interesting that the taller Frenchman is taking more strokes.

On the way back, things change. Lezak takes 34 strokes, and Alain takes 42. Something happened to Bernard's stroke on the way back, something that didn't happen to Lezak.

Looking at this video again, it's clear that Jason has a very different stroke than Bernard. Maybe it's because he breathes only to his right, and does so on every stroke. But I think there is more going on than that. From the top camera, watch Jason's head. It's going up and down a lot more than Bernard's. Watch his back. His back is pumping up and down more than Bernard's as well. From the underwater camera you can see that Jason is pumping the left side of his body up and down. Bernard goes straight through the water, which looks more efficient, but I don't think efficiency is what is going on here. I think Jason is pumping water backward with his whole torso, like in the butterfly.

One other note: Jason is blowing so much air under his body that his left hand is travelling through that air. Grabbing air cannot be helping propulsion, but it's possible that by getting that air under his body he is reducing his drag.

I'm pretty sure Jason Lezak has found a better way to swim the freestyle.

The Toy I Always Wanted

When I was a kid, I used to dream that I could make stuff pop into existence if I could just imagine all of the details.

Now I have SolidWorks.

I draw stuff. It takes a really long time to draw anything, compared to doing it by hand, just like I imagined it would. But once you get the hang of it, you can push a lot farther than you can with hand drawings.

Once drawn, I crank out dimensioned drawings, and then call people who build things for me. And they look just like the drawing.

This is what I wanted when I was 8.

Last weekend I made a model of one of our new gates.

Then I made a drawing of that:

While I was at work this week, Jesus came by and built it for me, and now I have the first of three new gates:

Obviously, this isn't quite the same as what I drew. The back gates are much shorter than the front gates. Jesus doesn't need a seperate drawing for each gate, just the idea of what I want.

I started out with hand drawings of the gate, and for this project, I probably could have just left it like that. But it turns out that hand drawing curves, and trying out lots of different curves and ratios to see what you like, is not so easy. With a parametric CAD system, you draw it once and then fiddle with a few numbers until you like the way it looks. Much better.

Coping being cut

Our in-ground pool is actually raised out of the ground slightly (18 inches near the house). This makes the side a nice bench to sit on, keeps cut grass from blowing into the pool, and should interfere with running and jumping into the shallow end at a steep angle.

One consequence, though, is that our coping stones are a nonstandard width. We've decided to have bullnosed coping (so these are bullnosed both sides, also nonstandard), and that requires that the coping overlap the waterline tile by over two inches. This kind of thing adds up:

• Waterline overhang: 2.5 inches
• Tile thickness: 0.25 inches
• Thinset: 0.375 inches (that's a lot, to give the mason plenty of freedom to flatten the wall for the enormous glass tile mosaics that are going in)
• Bond beam: 12 inches
• Thinset: 1 inches (the outside of the bond beam is quite uneven)
• Facing stone: 1.25 inches
• Exterior overhang: 2.5 inches

All up, we've gone for coping that is 20 inches wide.

We actually had a order placed for some very nice pearl white travertine (from Olympic Stone). When it came time for them to come by and pick up the check... they didn't. We called back and found there was some sort of problem... they didn't actually have the stone. it would be a 3 month delay to get it from Turkey.

Well, that's never a good thing to tell a customer. Martha started looking around, and found another very nice stone, this one a three color granite, from American Soil. This one is more expensive, but it really is pretty, and it's available right now. We ended up buying it. (We may use OSM's pearl travertine for the face of the pool rather than the coping, since they apparently have the 1" stuff available.)

[Update 16-Nov-2009: The pearl against the walnut travertine ended up not looking as good as we'd hoped, so we ended up using the walnut travertine on the sides of the pool. You can see this in the mid-November post.]

By "it", I mean a 12 ton boulder imported from Columbia, California. You can get a sense of scale from the pickup truck at the back right. This rock is a little shorter than I am.

It came from over here:

View Larger Map

They're chopping this thing up into 20 inch wide by 36 inch long by 2 inch thick coping stones for us.

This is a cable saw. The cable has some kind of abrasive on it (I've never actually seen the thing stopped, it appears to be running all the time). The huge wheels drive the cable through the stone. Above and below, they're whacking the top off the boulder.


Below, they're cutting the ends off. In this pass, the rock stays put and the machine basically drops through it at a half inch per minute (I'm not really sure, as I never saw the saw make any noticeable progress through the rock).

Here's one of the slabs coming off the cable saw, going into their indoor facility for shaping. You can't really see all the color here, but there is white, black, and some pink to it.

Here's the rock all chopped up:

There's a lot of white in some of these. Hopefully they'll be able to cut around that to some extent.

Not so much in others.

This equipment is usually used to make countertops.

American Soil just got a brand new Italian machine for cutting and bullnosing. This isn't it, since apparently that machine can't cut a straight line just yet.

Each stone should weigh about 140 pounds. I'm sure the mason will be very happy to hear that.

I'm really happy with how this looks. We still have some risk, in that the coping could have huge blobs of white in it, or the grain could get mismatched, but the folks at American Soil seem to be on top of that.

We've also picked up all our glass tile. It gets installed after the coping, but I'll try to post some pictures of the pieces assembled in our garage so you can get a feel for it.

The Limits to Growth

Folks in an apocalyptic frame of mind will sometimes consider what would happen if everyone in the entire world were to adopt a lifestyle which consumed resources at the rate of those of us in western countries. To keep this blog post short, I'll not address the entire problem, but I would like to point out that carbon emissions need not be a problem.

I'll take as my example the French. French people live a pretty good life on about 6.1 tonnes CO2/person/year, which is the lowest of the countries in the G8. The French low consumption is possible because their electric sector doesn't emit significant CO2 or burn significant fuel and has stable prices (it's 85% nuclear and 10% hydro). So as gasoline prices have gone up (mostly taxes, but large increases in crude costs too), folks have switched to electrified mass transit. Their electric-powered TGV trains carry almost as much traffic as their domestic airlines.

Is French low consumption really a result of nuclear electric production? Yes. Consider Germany at 9.8 tonnes CO2/person/year. That would be 5.9 tonnes CO2/person/year if their electricity sector was nuclear, which is about the same as France.

[Update: for comparison, the United States would be at 11.3 tonnes CO2/person/year if we replaced all our coal and gas fired powerplants with nukes. If we replaced half our air transport with electric trains, it would help a bit more, but I think less than 1 tonne CO2/person/year.]

My point is that the French example can be applied to many countries. Now here's an interesting thought. What if the entire world were to adopt the French lifestyle, including the carbon-free electric system? How catastropic would the emissions be?

The world population is now 6.7 billion, so at 5 tonnes/person/year, that'd be 33.5 billion tonnes/year. Compare that to our current emissions of 28.4 billion tonnes/year. It's larger by 18%. Something to work on, not a catastrophe.

Obviously, it's not quite so easy. Right now, a fair bit of the carbon going into the air comes out of the ground in solid form. If the entire world were to use nuclear electricity, coal production would nearly stop (it's still needed for steelmaking), and all that carbon would be coming from petroleum and natural gas. That would take a fairly drastic increase in production capacity for both, leading to a rapid depletion of existing stocks.

The summary: anti-growth doom and gloom is unnecessary in the electricity sector, so long as folks are willing to follow the French example.

Side note: French reactors are almost all inland and cooled by river water. This is perhaps an example best not followed. The French have laws which prohibit those plants from releasing back into the river water which is too warm. So, during a heat wave two years ago, some power plants reduced generation in order to reduce their output temperature, right as electricity demand was spiking.

Seawater cooling is much more reliable, and doesn't use up fresh water either. Some day, when we have high-temperature molten salt reactors, we will be able to air cool our nuclear plants, and then this will not be an issue. Until then, we should probably build the majority of nuclear power plants near the coast.

Almost time for a new car

Our minivan has hauled our dogs, kids, and gear for almost 9 years, and it's starting to show. In another couple of years, we'll need a new car. So, if you're building cars and wondering what to build next, let me tell you what we want.

The last time I knew I was going to buy a new car, I wrote a letter to Chrysler two years ahead of time. Fat lot of good that did. This time, I'm asking for essentially the same thing. I'll post it on my blog instead.

We want a plug-in hybrid minivan. Plug-in hybrids face a couple of big problems: the batteries are too heavy and the engine runs intermittently, which prevents the catalyst from firing up and leads to nasty emissions. I think both these problems are completely solvable for a practical vehicle that we would buy in a heartbeat.

First, I'll point out that 1100 pounds of lead-acid batteries can store 16 kilowatt-hours, which is the government's definition of an electric vehicle. Those batteries can survive five years of cycles through 30% of their capacity. 4.8 kilowatt-hours is enough to push a minivan 13 miles. That's less than the average daily drive of 33 miles, but for a minivan used for multiple short trips a day, it's easily good enough.

Next, I'll point out that the emissions problems can be solved by delaying the first ignition of the engine. If the minivan can get to 50 MPH on batteries alone, then it can avoid the engine everywhere but on the freeway. For most trips our miniman makes, that means no engine at all for most trips, and that basically eliminates the emissions problem.

Finally, I'll point out that regenerative braking extends the EV range just a bit, and comes with a lot of complexity (control interaction with the friction brakes) and cost (fancy controllers). I'd certainly be willing to live without it if it cost $1000 and only got me an extra mile of range.

Here's what the minivan would look like:

• Packaging
  • It should have seating for 7: 2+2+3.
  • It should carry many 4' x 8' sheets of plywood in the back.
  • It should have two sliding side doors, etc, just like real minivans.
  • Seats do not have to stow. They can come out like my current minivan's seats do.
  • Including battery pack, it should weigh 5200 pounds. That sounds like a main battle tank, but it's pretty reasonable once you think about the 1100 pound battery pack.
  • Weight distribution should be close to 50:50 front:rear, and the center of mass should be very low, so the thing should handle reasonably well.
  • The thing should be quiet when driving in EV mode.
  • It should plug into a normal 3 prong 120V AC outlet.
• Performance
  • 0 to 60 in 10 seconds. (Requires an average of 115 wheel HP.)
  • 0 to 60 in 20 seconds on batteries. (Requires an average of 57 wheel HP.)
  • 75 MPH up a 6% grade with 1000 pound load. (Requires 77 wheel HP, plus whatever is needed to go in a straight line at 75 MPH. 115 HP ought to do.)
  • Maximum cargo load of 1400 pounds.
  • It should go 13 miles on a 30% cycle of the batteries.
  • It should go 350 miles on a full tank.
  • EV mode should work: the car should be able to cool a hot interior and get to 50 MPH without starting the gasoline motor.
  • 20 MPG from the gas engine alone. That's about 4000 joules/meter of gasoline energy, or 15 cents/mile for gasoline at $3.00/gallon.
  • It should use about 800 joules/meter of battery energy. That's about 4 cents per mile for the electricity, at the average US residential rate (10.5 cents/kWh).
  • The batteries should charge from 70% to 90% in 90 minutes from a standard plug.
  • The batteries should charge through a 30% cycle in 5 hours.
• Drivetrain
  • It should have front-wheel drive from the gas engine.
  • The gas engine should be a 2 liter 4 cylinder engine with around 130 horsepower. That sounds anemic, but add 60 electric horsepower and it's a whomping 180 HP.
  • It should have rear-wheel drive from the electric motors.
  • The motors should deliver 60 horsepower at 30 MPH (torque limited below). This will give excellent performance in deep snow over pavement.
  • The electric motors can have their torque die to nothing at 70 MPH. Any faster and the gas engine is required anyway.
  • It should have about 1100 pounds of lead-acid batteries, which deliver 17.5 megajoules with a 30% cycle. This just hits the 58 megajoule full-cycle battery that the US government is willing to subsidize as an electric vehicle -- $7500!
  • It should have a 330 watt solar panel covering most of the roof. This sounds silly but it's actually a good idea. The panel adds about 4 miles of electric range on an average day in California, at almost the same cost per mile of range as the battery, with very little weight.
• Cost
  • The thing will go 17.5 miles a day in EV mode if charged only at night and parked in the sun, and 27 miles a day if charged at work as well. If used as a daily driver, it'll cover 6,000 to 9,000 miles a year in EV mode.
  • It will save around 5 or 6 cents per mile. Obviously, that's not why people would buy it, but it does make for $300 to $500 saved each year.
  • The roof panel will cost about $1200.
  • Battery swap costs $1800 (half of the new cost). Batteries should last 5 years, or 1800 30% cycles, so that they cost 6 cents/mile. Existing lead-acid batteries already achieve this cost.
  • The added cost will take 10 to 15 years to pay back (if you ignore the subsidy).

I think the drivetrain can be a lot simpler than a Prius drivetrain. In particular:

• The electric motor/generator on the gas engine doesn't need to be big. It needs to be big enough to start the engine quickly (maybe 10 horsepower), and that's about it. I don't want to recharge the batteries from the engine any faster than 10 HP anyway. Gasoline costs 3 times as much as electricity from the plug, so the only reason to charge the batteries with the engine is if I can avoid starting the engine later in the same trip.
• Make sure the heater and air conditioner can run off the batteries. It's important that these be able to run right at the beginning of a trip without having to turn on the gas motor.
• Lead-acid batteries. Forget the fancy batteries. Even lead-acid batteries cost more than the electricity from the plug costs, other batteries are worse. Lead-acid can deliver the necessary range and power without the availability headaches of NiMH or Li-ions.

I think that roof-mounted solar panel deserves some explanation. It has a lot of interesting benefits:

• On a sedan, there wouldn't be enough roof area to make a significant solar panel. A minivan, on the other hand, has a pretty big roof, so the idea works better.
• The car can run its fans continuously when unattended. When you get to your car sitting in the parking lot in Phoenix, it doesn't hurt to sit down or touch the steering wheel. The interior won't disintegrate in the extreme heat either.
• When the ignition is turned off, it should be possible to turn on the A/C and get 70 cfm of air cooled by 40 F. That's enough to turn over the car's air every 2.5 minutes. It won't cool a car that's already gotten to baking temperature in the sun, but it will keep a car cool after you turn it off.
• Batteries don't like to be run down for long periods. With a solar charger, the car will get some juice every day, which can keep the battery topped up if you leave the car unattended for a while. This will improve the battery life, and it's just nice to come back to a car and have it fully juiced.

In our family, Martha would drive this thing, using it primarily to move the kids around. She makes multiple short trips each day, usually not on the freeway, so it would get plugged in regularly and probably only use gas for the trips to my parent's house, which is 55 miles each way. Since we'd get plugged in while at their house, the minivan would end up driving 80 miles on gas, on the freeway, where it gets 26 MPG. If we do twenty trips like that a year, we'd burn just four tanks of gas and our overall gas mileage would be 195 miles per gallon of gasoline.

"When did you last fill up?"

"Spring."

Seems like a winner to me.

World Wildlife Foundation donations suspended

At the July 8-10, 2009 G8 summit in L'Aquila, Italy, Allianz (a global insurance company) partnered with the World Wildlife Foundation to deliver and publicize a report on how the 8 richest countries in the world are doing at reducing their greenhouse gases. Sounds good.

WWF/Allianz "does not consider electricity generated by nuclear power a sustainable option", an opinion shared by many. Their trouble was that any simple ranking of countries will show that nuclear power has made France the world leader in reducing greenhouse gases. Since WWF/Allianz doesn't want to promote nuclear power, they cooked the numbers.

They didn't lie. There have been a number of outraged comments about this report, but these folks did not lie. Their footnotes say specifically that numbers for France were "adjusted as if electricity from nuclear power was generated from natural gas." The report also includes, in footnotes, the numbers correctly calculated.

One of those same footnotes says that "without the adjustment, France would rank first with Germany." Unfortunately, this comment is not supported by either facts, or by the WWF/Allianz numbers. By any numeric measure, France is way ahead of the rest of the industrialized world.

Because I feel that this report is intentionally misleading, my wife and I are suspending our donations to the WWF until they amend their report to rank countries based on facts. We're also going to have a talk with a few friends who also donate to the WWF. We don't do business with Allianz, so there's not much leverage there.

Those of you who don't actually care that much about CO2 emissions or global warming can stop here.

The report ranks the 8 richest countries in terms of their "past, present, and future climate performance". Here I've listed their overall ranking, along with WWF/Allianz' calculation of their emissions per capita and per million dollars of GDP.

1. Germany (12 tons/capita/year, 384 tons/M$ GDP)
2. United Kingdom (11 tons/capita/year, 334 tons/M$ GDP)
3. France (9 tons/capita/year, 276 tons/M$ GDP)
4. Italy (9 tons/capita/year, 328 tons/M$ GDP)
5. Japan (12 tons/capita/year, 367 tons/M$ GDP)
6. Russia (16 tons/capita/year, 1140 tons/M$ GDP)
7. United States (25 tons/capita/year, 567 tons/M$ GDP)
8. Canada (24 tons/capita/year, 668 tons/M$ GDP)

France got dinged because they have not improved emissions much since 1990 (they'd already built most of their nuclear fleet by then). I notice they also got dinged for not having strong mandatory targets imposed on utilities to promote energy efficiency. The report fails to note that in France, saving electricity doesn't significantly reduce CO2 emissions, so there is no need for such mandatory targets.

The report completely failed to note that France is building new nuclear power plants on its borders to export more CO2-free power. Not only is this action going to cause more improvement in Germany's CO2 output than Germany's own utility policies, but it is also going to be profitable, which means that France is going to be able to do it AGAIN in a few years. Germany, on the other hand, is busy bankrupting itself with huge feed-in tariffs, and is already switching from expensive, imported aranthracite coal to cheaper domestic brown coal which emits more CO2 and other pollutants.

The United States clearly needs to clean up its act. Which country should we model our environmental policies after?

Germany: 51% of German electricity comes from coal-fired powerplants. They are building or planning another 26. These will add 23 gigawatts of production. Germany will be forced close its coal mines in 34 years when it runs out of coal, at which point their coal imports will peak until they will switch to imported Russian methane. Germany also produces 4.4 gigawatts from wind turbines. There is a lot of talk about wind turbines but the power comes and will come from coal.

France: France closed its last coal mine in 2004. 4% of its electricity comes from coal. 78% of France's electricity comes from nuclear, and produces no CO2. Most of the rest (11%) comes from hydro, and produces no CO2. France exports 18% of it's electric production, and most of that (5.9 gigawatts, more than $2 billion a year) is sold to Italy, which is one reason why Italy's CO2 outputs are low.

Bottom line: WWF/Allianz fudged the numbers to support a policy goal. That's wrong, and we're stopping our contributions until they fix it.

It's a shame, by the way. I liked some of the other stuff they were doing.

Why New Nuclear

Senator Alexander Lamar has a white paper which well summarizes how I feel about our desperate energy situation, and lays out a plan for how to fix it:

Blueprint for 100 New Nuclear Reactors in 20 Years

It does have a thought which was new to me, however: Russia, China and India, as well as a host of other countries, have already built out a fair bit of coal, and are beginning a large build of nuclear. If their nuclear build fails, they will fall back on coal, and nothing the US does will change the course of global warming. If their nuclear build succeeds and surpasses us, they will cement their existing lead in the next major source of energy, and they will end up owning the base of our entire economy.

And this base is enormous. The US GDP was almost $14 trillion in 2007. Generation of electricity, at about $40/MWh, was $170 billion that year. But that electricity sold for $90/MWh, for a total of $373 billion. Electricity sales are 2.7% of our entire economy.

And consider industries that are part of that industrial base. In 2007, the United States used 4.1% of our electricity (170 million of the 4156 million MWh) to smelt 23 billion pounds of aluminum. That aluminum sold for $26 billion. The aluminum smelters probably spent around $40/MWh for that electricity, so the juice was 26% of their cost of goods sold. Since aluminum is an easily transported global commodity, their profit margins are thin and small changes in their costs can lead to large changes in who makes the aluminum.

We need to own our energy supplies. We need our own large forge to build the reactor pressure vessels (right now we depend on Japan). We need American companies to build, own, and operate these reactors. And we need it now.

What we really need is to stop the Waxman-Markey cap&trade bill, and adopt Alexander Lamar's plan instead. Write your congressman.

My Response to the New York Times

Here's a link to the New York Times article "Combative Start to Senate Climate Hearings".

And, here's my response:

I’m a Californian, I vote, and I want more nukes in my state. I’m fed up with the high cost of electricity. I’m pissed off that we switched from making plastics with our natural gas to making electricity — and shipped our plastics industry to China. That’s not environmentalism, it’s offshoring, as a direct result of public policy that my representatives voted in.

My power company is not incented to make good decisions about the power mix: when natural gas prices rise, they pass along the cost. When they look at natural gas they see a lower capital cost, and so they get the same return on less capital. Fine for them, but we get stuck with power prices that whipsaw our producers out of business. Ever noticed how inflation is quoted without the volatile food and energy component? We chose to make our energy prices volatile!

What we need right now are projects like the Hoover and Grand Coulee Dams: big, expensive government-funded projects that get lots of people working in well-paying jobs and deliver locked-in low priced power for a century or more. Nuclear plants are way better than hydro plants since they don’t kill fish (or anything else, for that matter).

I want to vote for a future in which energy prices are not volatile, and where the aluminum smelters and plastic plants come back to where we can regulate them and work in them. But I seem to be stuck between a choice between Green folks, who want to build temporary windmills which will kill our economy, and Conservatives who want to stick with imported fuels, which will kill our economy. Give me a third choice!

Fastest Freestyle Ever

The men's 400 meter freestyle relay at the Beijing olympics was amazing. The French team absolutely crushed the world record time, and the Americans squeaked past them. Right up until the last 50 meters, the French were in front.

Don't talk to me about Michael Phelps, the second-slowest guy on our team. Let's talk about Jason Lezak. Jason gets in the water at 2:38. (Watch the video here.) Look at his stroke compared to France's Bernard Alain. He looks pretty similar (to my untrained eye). And he turns in a time on that first 50m that is pretty similar: 21.50 versus Bernard's 21.27.

And then, after that last flip turn, Jason Lezak swims the next 50 meters in 24.52 seconds. Which sounds slow compared to those first 50 meters, but it's so fast compared to everyone else that he was one of only 3 guys in that race to swim in less than 47 seconds... and he beat the other two guys (both French) by 0.57 and 0.67 seconds. That's HUGE. He nearly did it in less than 46 seconds.

Watching back in August, it was immediately apparent to me that Jason changed his stroke after his flip turn. This morning I looked up the video on the internet, and it raises more questions than it answers.

First, Jason takes 34 strokes to Bernard's 42. It's not like Bernard is some short French dude -- at 6'5", the guy is actually an inch taller than Jason. Discounting the 7 meters that both guys got off their kick at the end, Jason managed to go 49.8 inches on each stroke, vs the paltry 40.3 that Bernard manages. And, since Jason is going faster, he's got more drag and so his hands should be slipping back more. Where did he come up with an extra nine inches?

For those last 34 strokes, Jason's form appears to go to hell. His timing is no longer even -- the delay after throwing his left arm forward is less than the delay after his right. Worse still, the change in timing has his left hand grabbing the air that he's blowing out, which has to be terrible for maximizing the purchase on the water the whole way back. Compare to Bernard, who efficiently vents smaller bursts of air under the left portion of his body while his left arm is airborne.

Notice something else that Jason is doing. He's ducking his head down after he takes a breath. And watch his right shoulder roll. When Jason pulls back with his right hand, he launches a portion of his torso up, over the water, and then when he pulls back with his left hand he is porpoising the right half of his body over that water.

Has Jason incorporated some of the body motion of the butterfly into his freestyle?

Another insulated pool

Back when I posted about the insulated in-ground pool that I'm building, I asked if anyone else is building such a pool. I've received a few answers:

• One reader in Melbourne is building such a pool.
• Several have been built in the United States, but only one of the ones I've heard of is residential. The rest are all commercial facilities.
• Insulated pools are standard when the pool sits on top of a parking structure. Apparently installations like these are simply impossible to heat if the pool is not insulated, and there are structural isolation benefits as well.

Up until now, though, no pictures! Thankfully, the reader from Melbourne has recently written in to share a few pictures of his insulated pool. Here's the standard picture of the dig:

The pool is 46 feet long, which is exactly the same length as mine. His is skinnier (10 feet wide) and more shallow (max 6 feet), which is appropriate for a lap pool. Below, it looks like they are installing an in-floor cleaning system. Very nice.

Below is a pic of the insulation going in. He is using Dow Highload 100, sold there as Dow HD300, in the same thickness that I used (2 inch). He says:

The insulation I'm using is Dow HD300 in 50mm boards. This product is made for insulating under coolroom floors with trucks driving on top, and is overkill given its compressive strength specs of 2% compression (1mm) after 20 years of 250 kPa or around 25 tons per sq meter. However, the pool contractor and engineers had never seen pool insulation done before and through an abundance of caution over-specified for the highest compressive strength product they could find to be sure it wasn't going to settle. With the loads from this pool of only around 2 tons per square meter, we have more than an order of magnitude margin of safety. In the end, the cost differential between this and lesser rated products was so small that in the interests of getting the pool contractor comfortable with signing off we went with the HD300.

The contractors didn't glue the boards to the soil with foam, instead they used the rather unsubtle method of nailing it through with steel rod. I had two concerns about this:

• This will mean there's some heat conduction losses through the steel rod from the soil to the concrete, though the total surface area of steel in contract with the cement shell would still be minimal so this probably isn't a big deal.
• A risk of the rod eventually rusting and applying pressure to the concrete shell, but the foam will (I hope) compress enough to accommodate any rust expansion and prevent concrete spalling off the shell were this ever an issue.

The upside is at least I don't have to worry about the compression issues for the expanded foam glue you'd used and hence avoids the risk you mention in your blog that this may place extra strain on the shell as it settled, and from the photos it seems the contractors have got a good solid base without the rocking problems you'd mentioned.

The steel rod seems like a good idea. I tried to find an equivalent product here and failed, which is why I ended up with the polyurethane foam. One other contractor I've talked with in the U.S. also used foam, but I neglected to ask him if he chose not to use steel nails for some reason.

Here in California we use Dobies to seperate the rebar from the ground/insulation. Dobies are simple 3" x 3" x 3" concrete cubes with a wire in them. Check out the much snazzier looking rebar spacers they use in Australia. The wall does not appear to have a bond beam at the top, but instead is pretty thick the whole way up.

Insulating the piping has been a major effort on my project. It's not clear in these pictures if this pool's piping is insulated.

Gunite going in:

His pool is in basically the same condition as mine right now. Note the clever combination of bench seat and stairs at the right hand side of the pool. Very nice. The pool looks deeper than it is because the lot slopes up to the left, and the left hand side of the pool is a retaining wall (raised bond beam).

It's a nice looking project, and I'm very curious to see how it turns out. Thanks a lot, Melbourne!

A professional look at The Day After

Here is a set of essays on the calculus of nuclear war, written by someone who used to plan nuclear war.  They are short, funny in places, reassuring in places, and generally scary.

http://homepage.mac.com/msb/163x/faqs/nuclear_warfare_101.html

http://homepage.mac.com/msb/163x/faqs/nuclear_warfare_102.html

http://homepage.mac.com/msb/163x/faqs/nuclear_warfare_103.html

Of course, no mention of nuclear weapons is complete without directing readers to the Nuclear Weapons Archive, by Carey Sublette.  I remember first reading the FAQ in 1996 or so, and being astounded.  It changed the way I thought about The Bomb.

http://nuclearweaponarchive.org/

It's the physics bit that got me.  I had previously though of fusion bombs as being somewhat like the Sun, only, here.  But it turns out that fusion in the Sun proceeds along quite slowly, at comparatively low temperatures and pressures.  Fusion bombs operate at much higher pressures and temperatures than stars do, and (obviously) on much shorter timescales.  It turns out to be almost completely different physics.

For some reason that really bothers me.  The notion that we use physics that can't even be observed anywhere in the natural world seems odd.  Perhaps I'm succumbing to nuclear hocus pocus, since I can't think of anywhere in the natural world that we can observe hydrocarbon-oxygen combustion at dozens of atmospheres of pressure, and yet our cars and airplanes do that all the time.

You are so beautiful, Kathleen

Reynolds number

It looks like one of the problems with the fountain is that I'm pushing slightly too much water through the flow straightener.

At very low velocities, flow through a pipe is laminar.  I wanted laminar flow in the flow straightener because laminar flow has no turbulence which can then break up the output jet.  It turns out that the flow velocity in the pipe has to be incredibly slow, and it turns out that I managed to design my fountain to be right in the transition region between turbulent and laminar flow.

Here is the Engineering Toolbox link on Reynold's numbers.

At full flow, I'm pushing about 180 gallons/minute through 16 of those flow straighteners.  Each has an internal diameter of 15.3 cm, so that the flow rate is 3.85 cm/sec.  Plug that into the handy calculator (the one using kinematic viscosity) and you get a Reynold's number of 5213.  That's turbulent flow.

At the flow tested in January (which worked properly), I was going up about 33 inches instead of 65 inches, so my jet velocity was 71% of full flow now.  Also, the cross section of the jets was .41 inches instead of 0.5 inches as it is now, so that the velocity inside the flow straightener was 48% of what it is now.  Plug 1.84 cm/s into that Reynold's number calculator and I get... 2491.  That's transient flow, but quite close to the 2300 needed for laminar flow.

If this is really the only problem with the fountain, then I ought to be able to slow down the flow enough to get the Reynold's number down to something around 2300, and see laminar flow at the output.  How slow?  To get half as much flow, the jet velocity is halved, and the arc height goes to 1/4 of what it is now, or 16.5 inches.  In fact, at that velocity, I do indeed get laminar flow:

Note that the impact here is on the first step into the hot tub, which is a little lower than the nominal water surface, and the arc is about 20 inches above the nozzle rather than 16.

The jet is well behaved until it gets to the top of the arc, where the bottom of the jet interferes with the top of the jet, and the result is that is spreads out laterally. That lateral spread then turns into an oscillation in the flow until it hits the step.

Anya demonstrates that the jet is 18 inches above the bond beam, or about 20 inches above the nozzle.

At this point the default setting for the fountain is to throttle back to 40 inches throw height, which clears the occupants of the hot tub and isn't too noisy.

If we wanted to get the tall jets to behave properly, it appears we'd need to cut the flow rate approximately in half, which means we'd have to reduce the jet diameter to 0.350 inches instead of 0.500 as it is now (so the finished hole diameter would be 0.440 inches).  That means I'd have to pull the stainless steel nozzles (recall they are epoxied into the PVC heads right now), get new nozzle made (probably $300), and epoxy them back in.  That all sounds possible, and certainly cheap enough, and probably can be done fast enough given that it's going to take 5 weeks to get the tile delivered.

However, there's a good chance I'd just destroy the PVC heads in the process, and there is also a good chance I'd get the nozzles glued back in crooked.  I don't think we're going to try.

We're getting more comfortable with how it looks.