Missouri to Columbia River Canal

 People who have never been there have suggested making a canal from the Missouri River to the Snake or Columbia River, which would, they think, make transcontinental ship traffic possible.  Here's one:

Here are some facts:  The Missouri River is only navigable up to Sioux City, Iowa, which is right where South Dakota, Iowa and Nebraska  come together--in other words, less than half way across.  The part upstream of St Louis needs periodic dredging. 

The  Snake River is navigable up to Lewiston, Idaho, where it splits into several tributaries, all of which are way too small for anything much bigger than a ski boat.  And there are lots of waterfalls.  The connection on the map appears to be the Clark Fork river, which runs through some mighty rugged country.  I've driven alongside it for substantial mileage: turning it into navigable water is not a credible option.

 We already have many transcontinental routes which are vastly more practical than waterways.  They are called Railroads, and Interstate Highways.   It's important to realize that America stopped digging new navigable canals (e.g. the Erie Canal) pretty much as soon as railroads became viable--it was simply not economically competitive anymore.  Europe was much farther into their canal system at that point--it made sense to connect up canals, especially in northern and western europe, where the land is pretty flat.   Most of the canals dug in the last 150 years have been aqueducts--not for moving boats, but for moving the water itself. 

Metric Taps and Dies

 I just learned a powerful advantage that the metric system has over earlier systems.  Specifically, Taps and Dies.  When you're drilling a threaded hole in the SAE system, you need to look up in a chart what the correct size drill is, as it's not simple.  SAE uses two main systems for sizing tapped holes:  1/4" and bigger, the measurement is the bolt size, and then you have a number of threads per inch.  Smaller than 1/4", machine screw sizes are numbered 0000, 000, 00, 0, 1, 2...8, 9,10, 11, 12.   Every shop in America has a tap table, telling you what size drill to use for what size and pitch machine screw, and is it a sensible system?  No, they have numbered and lettered drills.  Some taps have the drill and clearances sizes etched on the tap, but they're often illegible and for the smaller sizes.

 Metric doesn't have this problem.  Metric screws are described by screw outer diameter and pitch length.  Standard 60 degree threads make the tap hole easy.  So an M8x1 screw is 8 mm in diameter and has threads 1 mm long.  So to drill a hole with 90% engagement, such as into plastic, you simply subtract the thread pitch from the diameter to get the hole size.  To get a clearance hole, you drill a hole a little larger than the thread outer diameter.  No tap table is needed. 

 It turns out that this is both a benefit and a curse.  You can get an amazing variety of metric taps and dies, where SAE has largely standardized on Coarse and Fine threads (UNC and UNF), which are of course different for different sized bolts.  The benefit of that is that the SAE has also made some strength definitions, which are enormously powerful if your bolt will be stressed highly.  Most metric tap and die sets will have roughly the equivalent of UNC and UNF, but you can get threads both finer and coarser. 

Archimedes Mirror

Lot's of people have thought that the great Syricusian polymath Archimedes made a weapon capable of setting the sails of ships on fire from a distance.  There is no historical evidence of this--the story seems to come from the middle ages.   The Mythbusters, several times tried to repeat this stunt, and failed every time.   While I can see problems with the individual experiments, I think they got it right--for several practical reasons, Archimedes probably did not try to set sails on fire by using individual flat mirrors focused by hand.  He may have experimented with it, but like the mythbusters, failed at every attempt.

That said, it is definitely possible to set things afire with a large mirror focusing the suns rays.  You can buy a hand held cigarette lighter that works this way, and a larger mirror can generate a fire at a distance of a few feet.    An accurately enough focused mirror could definitely start a fire at a distance, but it needs to be pretty accurate.  It's remotely possible that the mechanics of Syracuse could have made such a mirror, but I'm certain that had Archimedes seen such a mirror under production, he would have noticed the optical magnification it would have provided, and he'd have invented a reflecting telescope within days. This obviously did not happen, so I don't think Syracuse made such a mirror.   

Why the PNW Will Never Have High Speed Rail

 I live near Seattle, and I love it here.  We're a little isolated from the rest of the country, which is both good and bad.  One of the bad things is that it takes frustratingly long to get to any other part of the country.  If you want to get there in less than a day, you need to go by air.   It takes 24 hours to get to the nearest other region, the San Francisco Bay Area, by rail, or 13 hours by road, but only if you're lucky with traffic and break the speed limit a lot.

Lots of people advocate for High Speed Rail, and I am very much one of them.  An imaginary 200 MPH (300KPH) HSR system could get us from Seattle to San Francisco in 3.5 hours.  If the stations are near to your destinations, it would be practical to get to a meeting and back in a work day.  This isn't really practical by air unless you fly private--Airports are half an hour or more outside of town, and TSA adds 90 minutes or more.  Add that to 2 hours in the air each way and it adds up to 4.5-5 hours travel time each way.   Add that to the meeting itself and it's a 12 hour day or more.   Private Jets are slower, but not that much, and they subtract all of TSA, and they can be precisely scheduled--it makes the one day round trip possible, which it just isn't on scheduled flights.  So the people who can afford it, do so.

The Northwest has three big cities: Vancouver, Seattle and Portland.  Metro Vancouver has about 3.4M, Seattle, 4.2M and Portland 2.5M.  But those three cities are in a geographic island:  There's a huge mountain range between central Oregon and the Central Valley of California, and two even bigger mountain ranges to the east.  It's over 600 miles from Portland to San Francisco, and about 300 of them are really rugged terrain.  The SF Bay area has only about 8 million people: less than the PNW.  To make a High Speed Rail Corridor really practical, LA/San Diego, about 20 million people need to be added.  And once you've done that, you need to connect to the rest of the country.  Spokane, Boise, Helena and the other northwest cities are tiny.   You need to go down to Salt Lake City and Denver, or up to Calgary/Edmonton, to reach many folks.  

 There is already rail through all of these routes, but a lot of it is very far from being able to handle High Speeds.  Through the Siskiyous, it's barely able to handle moderate speeds and there are some radical twists and turns.  Making this capable of even 200KPH, will be incredibly expensive, much less 300.   A bunch of the existing route is comfortably able to do 80MPH--but less than half.  All the terrain north of Eugene will need to be moved into the Willamette/Cowlitz/Nooksak Corridor, and rebuilt to HSR standards.  The construction cost to do this is at least $100M/mile for the 700 miles from Eugene to Vancouver--$700B, and that doesn't factor in the cost to obtain the land and get other political clearances. Figure $2T.  Redding to San Diego is about the same: 700 miles/$2T.  Finally, you've got to do the mountains: Eugene to Redding is about 300 very mountainous miles.   That'll probably cost at least $2T, maybe even more.  

 Would it be worth it?   Perhaps.   The roadbed that's already in the various flat corridors will be cheaper to obtain than the portion that's not.  Near Seattle runs along the Puget Sound Coastline, and will be useless for our purposes--Everett to Olympia, well over 100 miles, and apart from the cities themselves, that's probably the most expensive land on the route.  Such a system will stimulate business enormously--but $6T is a lot of money: about 2 years GDP from the entire affected region.  

----

 In the long term--surely not in my lifetime, we will have some form of VacTrain.  Hyperloop or maybe something even better.  Many pundits argue that this will be quite a bit cheaper than HSR, and I see their point: Hyperloop takes a tiny amount of space, and tunnels and bridges are much less substantial than for trains.  A Tunnel Boring Machine through the Sikiyous would solve a mess of problems.  Not sure it's possible, but it's an appealing thought.  Not just 200MPH.  1000 MPH.  Seattle to SF in 45 minutes, no waiting anywhere. 

2026 Electricity Cost, by Source

These are the fully burdened costs of each electricity source, counting capitalization, construction, maintenance, fuel depreciation, etc., as of today

Coal                        .092 to .23 per kWh

Natural Gas            .065 to .10 per kWh

Hydro                     .02 to .06 per kWh

Nuclear                    .037 per kWh

Utility Scale Solar  .03 to .05 per kWh

Residential Solar    .14 to .18 per kWh

Wind                       .024 to .075 per kWh

 

The bottom line: as of today (a couple of years ago, actually), utility scale solar was cheapest and shows signs of continuing to come down.  Hydro is #2, where you can get it, and that price has been stable for some time.  Wind is #3.  Nuclear is potentially competitive, but there are a lot of complicated externalities which make the cost in the table nearly impossible to achieve.  The recent standby, Natural Gas, is now close to the bottom of the heap, and the old standby, Coal, is significantly more expensive.

There are very few externalities from Solar.  The initial cost of the panels, once very large, is approaching trivial and the cost of the land is dominant.  They have very few environmental consequences. (although not zero: the shade changes hunting patterns for predators, for example, and productivity of farmland is somewhat reduced).   The panels last for decades, although recycling them when they eventually do wear out is a small problem.

There are more externalities for wind.  Perhaps the worst is that they interfere with the flight of some birds.   They make a noise which can be annoying if you're close, and some people find them unsightly.  They last 10-20 years, and most of them can be recycled into new windmills when the time comes.

Hydroelectric power has a very high upfront cost, and a theoretical lifetime of about a century, but the production costs are extremely low.  They turn out to have had a much more profound impact than was at first realized, especially on wildlife, such as fisheries.  Fish ladders had seemed to work, but a lot of them were defective and only a tiny fraction of the fish got through, for example.

 Natural Gas, mostly produced in the US as a byproduct of oil drilling, or hydraulic fracturing, has come on line quite strongly in the last couple of decades.  The fuel is comparatively cheap, and produces less CO2 and other pollution per kWh than burning coal or liquid fuel, such as gasoline.  But still quite a lot.  Another useful technology has been Combined Cycle turbines, which pair an internal combustion gas turbine with a steam turbine that exploits the waste heat.  They're able to get 60% or more efficiency, while conventional turbines struggle to get 40%.  But perhaps the biggest advantage is that an individual turbine can be throttled, to match demand, without much efficiency loss.  This makes it incredibly useful as a variable power source that's easily adapted to rapidly changing situations.

Coal is a historic fuel.   Because it was easily available in most of the places to industrialize early (e.g. Scotland, northern Germany, much of the US, China), it was a convenient energy source, and in a very real way, powered the industrial revolution.   It is difficult to throttle power generation to match demand, and all of the ways cost a lot of efficiency.  Moreover, it's dirty, inefficient and has lot of nasty externalities, such as open pit mining and mountaintop removal.  It's been the most expensive of the leading ways to produce energy for about 3 decades and has been rapidly declining in popularity.

Metric vs English System

 I think it's important to understand that the metric system is in some ways superior to the english system of measurement, but in most ways equal.  That the US is stuck on the English system is an accident of history.

During the middle ages and earlier, every region had its own set of measurements, all a little distinct, and in most cases, the units didn't relate well to each other.  France and the rest of Europe pretty much stuck with the old ways--there were at least a dozen distinct units call a foot (pied) in France at the time of the revolution, all a little different from each other and none relating particularly to longer or shorter units.  Britain had this same problem, but in the late 1500s, Parliament decided to rationalize this.  They determined, by statute, that a foot was 12 inches, a yard was 3 feet, a chain was 22 yards, a furlong was 10 chains, a mile was 8 furlongs, an acre was 10 square chains, (or a furlong by a chain), and so forth. This happened to be at the start of the great period of British colonization, and as a consequence, these statute measurements found close to universal acceptance in the largely British American colonies.  They made far greater sense than the mess of the rest of the world.

One of the fads at the time of the revolutions was decimalization.  When Hamilton and others were deciding on a currency for their new country, they embraced the new idea, and went with the decimal dollar.  The english system of money at the time was a mix of sensible and less so:  the pound was 240 pence, split into shillings, but also split into other weird things like a guinea.  240 is divisible by 3, which is not true of decimal systems.

During their revolution, the French decided, finally, to rationalize their system and based it on navigation:  there were exactly 10,000,000 meters between the equator and the north pole on the line that ran through the Louvre, in Paris.  The US president at the time, Jefferson, thought this was a good idea and got the french to send a standard meter and kilogram to Washington.  Unfortunately, the ship was lost at sea and they never got there. Rather than cook up their own, possibly different versions, the Americans stuck with feet, inches and pounds, until another set of standards could be sent from France.  Unfortunately, the French government never got its act together to send another.

At the same time, something really amazing was happening--the industrial revolution.  This started in Britain (Scotland) but soon spread to America.  All of a sudden, standardized parts were all the rage, especially things like Nuts and Bolts, because that made it possible to outsource large parts of your manufacturing process, and suddenly manufacturing was a Big Deal.  The US standard, which has come to be called SAE (society of automotive engineers) measured things in fractional inches and threads per inch, but they did something very special: they established a rating system for the strength of these components.     An American engineer was unlikely to specify a metric (or whitworth) bolt because it was harder to be confident of its strength.

I am an american trained as a scientist--I am perfectly comfortable with either system.  Most of the time it really doesn't matter.  1/4-20 is pretty close to 6mm .8 thread.  as long as I know which I'm using, the difference is unimportant.  There are a few cases where it does matter.  3/4 inches is a standard width for a lot of things, such as the width of electrical and masking tape.  Much of the time it doesn't matter.  But when somebody specifies 20mm, as they often do in Europe. it's a bloody pain to find this in America.  3/4" is 19.1 mm.  Close, but no cigar.   I just needed to get some holddowns for my workbench.  American dogholes are 3/4", european dogholes are 20mm. one will not work in the other.

Simple Machines

 As a child, we are taught that there are only a few simple machines and that most others are derived from them.  I think I was first exposed to this concept in the third grade.  Those are undeniably important, but I think some are really just variations on others, and there are a few that are missing.

Inclined plane.  You can use this to use a smaller amount of force to achieve a larger amount of force.  For example, a ramp, a stairway, etc., are all examples of inclined plane.

Lever.  This is a different way of achieving something similar.  Give me a long and strong enough lever and a place to stand, and I can move the earth, said Archimedes.  He also needed a fulcrum.

Wheel with axle.  This supports a weight and holds the wheel in place under it, while reducing friction and wear at the axle. 

Pulley.  The earliest pulleys were blocks of wood with a hole for a rope to pass through, and can be used to change the direction (lead) of a rope or give mechanical advantage.  This style of pulley gives us the traditional name for a pulley on a boat, a "block".  Modern pulleys have a wheel with axle to reduce friction and wear, but they're still the same concept.  On boats, they are still called "blocks".

The rest on the traditional list are derivations of these:

   The wedge is an application of the inclined plane, intended to split two things.  Knives, wedges and several other common tools use this variant.

   The screw is another application of the inclined plane, where the plane is twisted around a shaft.

There are other simple machines which deserve mention on the main list.

The wick.  A wick is an object, most often a treated string, that uses capillary action to move a liquid, often against the force of gravity.  Most commonly this is melted wax, such as in a candle, but there are many other variations.  The treatment is something that makes the string fire resistant, such as salt or borax, although sometimes the wick is made of something not flammable in the first place, such as copper or fiberglass.  The invention of the wick is lost in pre-history but nearly every culture used it--whether knowledge spread or was independently rediscovered is unknown.  Capillary action was not understood to be the underlying mechanism until relatively recently.  The first recorded observation of it was by Leonardo.

The gear.  This is derived from the wheel and pulley but the idea of using a toothed wheel to transfer force, and gain or lose mechanical advantage seems to date from a few hundred years BC.   While the ancient greeks definitely had gears and used them, the earliest engineers to use them on a major scale were the Romans, working in the 2nd century AD.

Archimedes was the earliest engineer we know of to design using gears but we suspect he didn't invent them.  The Antikythera mechanism is the earliest surviving geared mechanism, dating from the 2nd century BC.  It is a remarkably sophisticated computer for calculating the motion of the planets, the seasons, and other events.  It may have been designed by Archimedes himself, but we don't know.  It was discovered in an ancient shipwreck in 1901. 

The waterwheel and Fluid dynamics.  The ancient greeks seem to have invented the water wheel, but again, the Romans were the first to really exploit them.  They are really a combination of other simple machines, but they're important enough to deserve mention. They had a number of variations, some using gravity, some using the force of the moving water.  In the 12th century, the dutch began using windmills, which are really the same thing, except using fluid dynamic lift instead of drag.  It wasn't until the 18th century that it was realized that this (called a "turbine") was the best way of doing it for all types of fluids.  The math was worked out by Daniel Bernoulli by 1738, but they really didn't catch on until the mid 19th century.  Traditional water wheels, including paddle wheel steam ships, were very common until that time.  A famous experiment was conducted in 1845 by Isambard Kingdom Brunel where he arranged a tug of war between two otherwise identical ships, one with paddlewheels and one with a screw propeller, and the screw prop won very convincingly, being able to pull the paddlewheeler against the current on the Thames river.

Is it Duct Tape or Duck Tape?

One of the most useful inventions ever is called Duck Tape or Duct Tape.  The earliest version appears to have been made from cotton duck cloth sealed with linseed oil and used to water proof things, and first appeared in the 1890s.  Later versions used rubber or various other flexible, water resistant coatings, mostly over cotton duck.  The Revolite division of Johnson and Johnson made a version that was easy to tear, so you didn't need to use scissors or a knife, and was used to waterproof ammunition cases during World War II, and became widespread among the troops for this and many other uses.  This stuff was found to be so useful that other manufacturers started making copies.

The fiber reinforcement makes the tape very strong, and the plastic or rubber makes it relatively water resistant, depending upon the adhesive used.  It's traditionally shiny grey although it can be obtained in just about every color imaginable, including transparent, and printed patterns, and it's usually 2 inches (50 mm) wide, although other widths are available.   Some time around 1960, the name somehow became conflated with the tape used for sealing furnace ducts.  This is one of the very few things it's not particularly good at: the heat tends to make it dry out and become brittle over time.   There is heat resistant foil tape which is actually the right thing for this.  Nevertheless the name change stuck, and a company was able to copyright the name "Duck Tape".

Present versions are usually based on a thin "scrim" which is a loose weave of some sort of fabric--all sorts, cotton, rayon, nylon, even fiberglass, depending upon the strength needed, and the grey part is usually Low Density Polyethylene (LDPE--type 3 plastic) colored with aluminum powder.  The adhesive is generally relatively strong, but relatively cheap, and tends to leave a sticky residue behind when it's removed.  Gaffer Tape is a variety that doesn't leave a sticky residue and is reinforced by stronger fabric, so it needs a knife or scissors to cut.   Preservation Tape is a variety that doesn't leave the sticky residue and doesn't have much or any reinforcement, so it's easy to tear.  Speed Tape, sometimes called Racer Tape,  is a variety that has a smooth surface and strong enough adhesive to tolerate the high wind of a racing car or airplane.  There are 100mph, 200mph, etc., versions.   It's sometimes used to make temporary repairs to airliners before a more permanent repair can be made.

There has been at least one roll of Duct tape on every US manned space mission since Gemini, and it played a major role in the rescue of Apollo 13.  It was also used to extend the fenders on the moon rover on Apollo 17 when they sprayed too much moon dust around.   It works, at least for a little while, in the vacuum of space.

It is most correctly called "Duck tape", although because of the copyright, it might have to be called "Duct tape" sometimes.

It is, as Red Green says, the Handyman's secret weapon.

Breakthroughs vs Debugging

When considering an engineering project, there are three potential barriers to succeeding:

Political/Economic.  These are things like funding and NIMBYism.  A store that wouldn't mind having your train station across the street may be upset if it's so close it requires them to find another location.  Such considerations need either to be bought off or taken by eminent domain. Enough such problems may make it impossible to implement your project with the funding you have, but are solvable problems, at least in theory.

Debugging.  It's rare that the first design of anything very complicated succeeds.  Some debugging or redesign is nearly always necessary.  Oversights, mistakes, shortcomings, misunderstandings, etc., always occur. The engineering or construction time to fix it costs money and if there's not enough available, the project may fail, but if the problem is one of debugging, it is a solvable problem.

Breakthrough required.   Some ideas are simply contradictions of the laws of physics.  For example, a nineteenth century scientist likely thought that traveling to the stars was just a matter of going faster and applying more energy.  But in the early 20th century it was discovered that the speed of light is an absolute limit and that the energy required to get even close to it was impractical.  To get to the nearest star will take more than a human lifetime.  Unless some breakthrough, like Star Trek's "Space Warp" technology is discovered.  It's conceivable but nobody has even the first idea of how to do it.

So, for example, Hyperloop (transit in an evacuated tube near the speed of sound) does not require any breakthroughs to succeed, although there may be some.  All the technology required is fully understood, in at least a general way.  There may be some friction from politics and engineering, but with enough determination, they are all solvable.

A space elevator (a cable anchored to a geosynchronous satellite) is mostly straightforward engineering, except for one thing: the cable needs to be strong and light enough that it doesn't break under 22,000 miles of its own weight.  No fiber presently known can do this.  There are some breakthroughs on the horizon that might succeed (e.g. carbon nanotubes), but this is impossible until there is an actual breakthrough.

Tesla Semi Charging.

Tesla has announced their long awaited Tesla Semi, along with a surprise: a new version of the Roadster.

The Semi is a class 8 truck.   Class 8 are the biggest trucks in regular use on the roads.  They're used for long haul trucking, dump trucks, cement trucks and so forth.  The prototypes they've showed have a slick aerodynamic cab and a close-coupled trailer.  My suspicion is the trailer will revert to the more conventional ones in most cases.   It has a center driving position in the cab, two large touch screens, and software that controls the independently powered wheels to prevent jackknifing.  He says it'll have 400 mile range, and a new, bigger than supercharger that they call a megacharger, which supposedly can charge the battery in half an hour.

400 mile range implies something between 600 and 1000 KWH of battery.  The biggest batteries sold with Teslas now are 100KWH.  Mine has an 85KWH battery, which others have discovered actually puts out more like 81KWH. 

Charging a 1000KWH battery with J1772 protocol at 80 amps (e.g. HPWC) will take approximately 50 hours.This is obviously not suitable for a commercial truck.  A conventional 125 KW supercharger brings this down to 8 or 9 hours, but Tesla is not presently selling these for commercial installation.   They showed the truck side of the receptacle for charging the truck with a "megacharger", which appears to have 8 holes in it, each a little smaller than the present charge orifice.   The present supercharger cable is pretty close to the limit of what a relatively frail adult can handle.  8 of them all at once is likely beyond what even Hafþór Björnsson could handle.  (He's the actor/strongman that plays "The Mountain that Rides" on Game of Thrones).   The strands might be connected individually, but more likely this connection is handled by a machine, such as the one Tesla demonstrated a few years ago.--the truck drives close enough to the charger and the cables are moved into place by a large robot arm.

Anything less than about 400KW is unsuitable for long haul trucking.  Long haul truckers may drive 11 hours in a 14 hour day.  400 miles is only about half of that.  So they need to charge twice a day, and in the case of drivers who share their truck, they may need to charge more than that.  This may be adequate for a lot of Class 8 truck applications though: Cement trucks and dirt trucks spend a big part of their day loading and their routes are often start and stop and stay close to home.  Trucks being used to move containers around within container terminals tend to spend well over half their day waiting in line.   A 100KW charger may well be adequate for these.  Tesla may choose to sell something resembling an existing supercharger for these applications, where the trucks spend their off duty time hooked to the charger.   And they may not need much more than an 20KW HPWC for trucks that serve local chains, like grocery stores, where the truck spends a half hour or more loading or unloading for every 20 minutes actually on the move.  But long haulers need more

I'm estimating about 1000 truck stops around the US.  Tesla would need to install megachargers at a large number of these.  A megacharger installation would resemble existing diesel refueling stations in that the chargers will need to be drive-through, like gas stations.  There will need to be enough of them at each location that nobody has to wait too long--remember that 14 hour limit.  The interesting part though is that the transformer for each megacharger plug needs to be about as big as a 12 bollard supercharger.  They can do the same charger sharing, so a 12 megacharger station needs transformers the size of that needed fo 72 individual supercharger bollards.  Enough to power hundreds of houses 

Interestingly though, on the scale of our national demand, it's not that big a deal.   250*12*400,000 is only 100MW.   25-50 of those big windmills.


adenda  18Nov17:
https://www.dailykos.com/stories/2017/11/17/1716536/-Further-thoughts-on-Tesla-s-EV-Truck-announcement-from-a-former-fleet-owner

Without the Asteroid

About 65 Million years ago, an asteroid or comet 10-15 miles in diameter struck the earth in what is today the Yucatan Peninsula, forming what is called the Chicxulub crater, causing climate change and killing most plants and animals, large and small, and making extinct all large creatures, including the giant lizards we call dinosaurs.  Some small creatures: small birds, small mammals, small lizards, insects, etc., managed to survive and almost all animal life larger than about the size of a human fist descends from the few survivors, including us humans. There are a few exceptions of larger creatures that survived, but all of them live mainly in water, such as sharks and crocodiles, but it's clear that only a small number of individuals actually made it.

If the asteroid had missed the earth, the big dinosaurs would probably still be among us. Without them, mammals were able to evolve to fill the top predator niches, but had the asteroid not killed them, dinosaurs would still be eating everything that's not good enough at hiding or running away.  The things that evolved into monkeys and apes would have had a much harder time competing until they grew the intelligence to turn the tables on the dinosaurs.

Were there intelligent dinosaurs?  Clearly yes.  Those surviving dinosaurs: crows and ravens, are nearly as smart as dogs and in some ways smarter.   They are more social than most other types of birds, and it seems like that ability to work together provokes the development of communication, and that feeds back into speakers ability to come up with increasingly cunning plans.  Other dinosaurs also worked together--The movie portrayal of Velociraptors is hyperbole to make a good story, but they did work in teams probably planned traps.  It's not that big a step to sitting around after dinner telling stories and making plans for the next day.  Our hands evolved from claws that are effective at climbing and catching prey to things that are better at using and making tools and weapons, which gave us a huge opportunity to generalize: select the right tool for the task, rather than being stuck with the one at the end of your arm.  Things like spears are essentially impossible for non tool using creatures.

Without the asteroid, a dinosaur would have evolved to fill this niche. Perhaps it would have developed the sort of awareness that we call intelligence.  It probably wouldn't have been one of the giants: a top predator has fewer evolutionary pressures than the middle sized ones.  It's easy to imagine them being bipedal (so they can specialize their hands and not need them for walking), neither too big nor too small; probably 3 to 7 feet tall, living in groups of a few families.  It's unlikely they could fly--all vertebrates with wings use the same limbs that hands are on, which would preclude them from handling and making tools.  But they might have feathers and tails.  There's nothing particularly magic about 5 fingers, but the opposable thumb is crucial, although it might be implemented in a variety of ways.   Could have 3 fingers and two thumbs, or 6 fingers and one thumb.  But being a vertebrate, they'd have the head on top and 4 limbs, which constrains the possibilities quite a bit.

In addition the smarter birds, there are several other critters that have developed pretty high levels of intelligence.  Dolphins are pretty smart.  Groups of them will make sophisticated hunting plans.  They clearly have a relatively sophisticated language.  Their lack of hands limits them.  Of course they developed well after the K-T asteroid--their evolution would have been different had the big dinosaurs survived.   Octopuses are also pretty smart and they don't use it for teamwork.  They are capable of pretty significant manipulation with their tentacles.  And they do predate the K-T asteroid.

Vinyl Presence

In the early days of recording the goal was to reproduce the music or whatever was being recorded as accurately as possible.  Early microphones, wax, and later shellac drums and disks, amplification horns and simple tube circuits were so inadequate, and very expensive, leaving little doubt whether you were listening to a recording or live music.  By the 1950s though, the technology began to catch up.  Speakers and amplifiers got better, microphones, got better, and perhaps most important, recording materials got better: better lathes, pressed vinyl disks, extremely lightweight diamond needles.  If everything was right, it was possible for a recording to win in a real A-B test.

One of the important things that was improved was that vague thing called "presence", which is based on our "ears" ability to place a sound accurately in a 3-D environment.   Our ancestors were both hunters and prey, and in such a context, this ability confers huge survival value.  So we have a whole bunch of very sophisticated mechanisms, most of which are almost completely instinctual.  Most of us cannot describe most of them, but they're there and they use them every day.  For  example, we use the slight difference in volume of a sound to place it left or right according to how our head is oriented.  We use difference in phase to determine whether this sound is close to on axis or how far away from the axis it is, giving us a 3 dimensional effect.  We use the pitch of the sound to determine how high it is: low sounds are lower, like rumbling or water, while breaking branches and flapping wings are higher.  And the most amazing part is that our brains and ears are doing this in milliseconds, on sounds that may not even have a full wave.

Early studio recordings were as acoustically as quiet as possible.   A room with as much sound insulation and damping as possible, so there would be no outside or reflective noise.  But as the techniques got better, it didn't take long to realize that something was missing.  The most important was reverberation: Every room, even a big outdoor performance arena, has a characteristic echo, and  recordings with no echo at all sounded weirdly sterile.  The solution was a device called a "spring reverb", which was a speaker and microphone connected to a short piece of spring, which would transmit sounds more slowly than air and could be adjusted fairly easily to produce a desired amount of echo.  Nowadays the same thing is done with digital electronics.

Next came stereo.  Two microphones were used in live situations and mixdowns to two tracks in studio situations to simulate the volume and phase difference that we use to detect position.  Attempts were made to do even better with 4 and more channels, but it turns out that they were getting into diminishing returns.  Some of these things still exist but they are mostly used for things like movie sound effects, so the rumbling or TIE fighter or whatever seems to be coming from behind you.

When the CD came along, one of the hobbies of audiophiles was to set up A-B tests between identical recordings on both CD and vinyl.  I participated in several.  With brand new vinyl and good equipment it was hard to tell.   Once the record had been played a dozen times or so, it was easy.  There were occasional scratches and pops, and there was a constant background hiss.

The way a stereo record is recorded, the lathe's cutter has two axes, each 45 degrees from the plane of the record and 90 degrees from each other.  A sound that's only to come from one speaker makes oscillations only on one, leaving the other stationary, and vice versa.  Since most sounds will come from both, this is mostly a 3 dimensional groove.

Imagine what happens when something happens to one of these tiny groves: a mote of dust lands on it, or a tiny scratch forms: the needle is deflected slightly from where it's supposed to be.  It's unlikely that this will be in perfect stereo phase so our animal brain puts it some random place in the sound field.  It's not even a full wave, so we don't actually register it.  Another comes along a few milliseconds later and we do the same thing at a different random place.  Our animal brain decides that whatever it is that's producing all of this has some size, and isn't just two disembodied speakers, but is present in the room.

CDs are unaffected by dust or scratches (at least within the limits) so they initially sounded sterile.  It isn't hard to synthesize "presence" though: just add a tiny amount 3D white noise.

addenda 27 Oct 2017

A lot of guitar amplifiers have a control called "presence", which slightly changes the equalization, boosting the upper midrange.  On some amps, this also includes some negative feedback for that range, which reduces distortion there, which are the fundamental pitch of the guitar are, but leaves (intentional) distortion alone across the rest of the spectrum--including white noise and the higher harmonics.

Aluminum Overcast

Someone--at least as far back as Bismark's general Helmuth von Moltke--said "No plan survives contact with the enemy."   It's consistent with the ideas of Sun Tzu although nothing quite like it appears in "The Art of War".

The US prevailed in WWII not by the superiority of its technology, although there was some of that, but by superior numbers.  The US industrial base was able to produce more planes, tanks and ships than our enemies.  That included producing a lot of them for our allies.  The German Panzer tank was significantly superior to the US Sherman, but a plan was quickly devised where three or more Shermans could defeat a single Panzer, essentially by trapping it and forcing it into a crossfire.  There were a lot more Shermans than Panzers so this tactic proved effective.  Liberty ships were produced in such great numbers for such low cost that they were considered to have paid for their construction cost if they successfully made a single shipment.

Before the war, there was some design work and a little advance production by the US, but the real work didn't start until after Pearl Harbor.  There were lots of big surprises.  For example, before the war it had been thought that bombers needed to be able to defend themselves, consequently B-17s and B-24s carried a lot of guns.  5 or 6 of the 10 member crew of a B-17 were primarily there to man the guns.  But it turned out it didn't work all that well and there were appalling losses of bomber crews, and work was quickly begun on a fighter with sufficient range to travel with them to the target.  Once the P-51 came on line, the bomber losses dropped dramatically.

During the Cold War, lots of ideas about the enemy promoted lots of ideas about how we should defend ourselves, and this led to an ever escalating rise in complexity and cost.  The various skirmishes that did occur: Korea, Vietnam, Iraq, Bosnia, showed how completely inappropriate the Cold War ideas about weapons were for the conflicts we actually did have.  B-1s, B-2s, F-117s, Nuclear Aircraft Carriers, etc., were all used in the Iraq conflicts, against enemies who were almost completely defenseless against those, and would have been almost equally defenseless against B52s and F4s, designed in the early 1950s.  (not completely: surface to air missiles took down a number of planes, including an F-117 during Bosnia.).  The most effective planes of the present generation, by far, are the drones, such as the Predator, which has performance not much more impressive than a WWI Sopwith Camel, but carries modern weapons and observation gear and can be flown remotely.

Recently, one of the more effective 1980s generation airplanes, the A-10 "WartHog", was retired in favor of the as yet undebugged F-35.  Each F-35 costs more than ten times as much and cannot do any of the missions the Warthog proved so effective at very well.  The F-35 program costs roughly the same amount each year as the SNAP "food stamp" program that feeds 5 million people every day.

We need national defense, no doubt, but we need to do it wisely.  The over-reliance on extremely complex military systems does not keep us safe; it does the opposite.  We are committing large portions of our treasure and talent to producing weapons that are not particularly useful.  At the same time, we're offshoring our once formidable industrial base.  Should we need to project force the way we did in World War II, we no longer have the industrial base that won WWII.  It doesn't appear that we have any enemies who could take us on, but should we be surprised, with our absurd military, we will almost certainly lose.

Pseudoscience Ascendant

I just returned from 8 days in my hometown, Cupertino, California.  Cell phone and cellular data reception there continues to be terrible, and if I use my phone much, the battery dies in a fraction of the time it does in more sensible places.   The home of Apple, HP and countless other high tech innovators, has very few cell towers, and these companies have been forced to implement their own private cell networks.  Here's the reason.  They have it exactly backwards.

The WHO report cited is essentially a sop, admitting that it's remotely possible that this could be a problem, just to get these nincompoops off their back.   There is no credible evidence that low level gigahertz radio causes cancer.  None.  Very high power, tuned and focused radiation can cook things though.  Microwave ovens are tuned to the frequency of water. They're shielded, but by staying a few feet away, even if there's a breakdown, you can stay safe. Powerful radars have been known to kill bugs and birds that flew too close.  Not by cancer though, by boiling the water in them.

But let's pretend that there was a problem.  Digital cell phones adjust their power output based on how far they are from the cell tower.  If they're far, they increase power, if they're near, they reduce it.  This has a bunch of advantages.  First of all, it saves a lot of battery power if they don't have to use it.  More significantly, it increases network capacity.    Each logical channel is only used up for as big an area as the power being used can reach.  The same channel can be used by another tower/phone pair if they're out of range.

But the notowerinschoools folks have this exactly backwards.  By keeping the towers far from the students, they are FORCING all cell communications to occur at high power.  The transmitter that matters is not the one in the tower.  The inverse square law makes it of little consequence to anyone more than a few dozen feet away.  The transmitter that matters is the one the kid is holding up to their ear.  If the tower 5 miles away, it's transmitting at high power.  It's unlikely to cause cancer, but it might be boiling the kids brains a little bit.  From less than an inch away.   The closer the cell tower is, the less power the mobile phone needs to use to transmit.  Unless you ban the cell phones completely, you are achieving exactly the thing you were trying to prevent.  I wonder how a cell phone ban would go down in the schools of Cupertino...not.

Idiots.

Addenda 3 Jan 2017

 There's a new cell tower in Cupertino near city hall that went on line in the spring. Cellular is now /much/ better there.

Recharging While Driving

Electric cars are here, and are already having a significant impact on the roads.  But they still have a problem with range.  The small ones: the Leaf, the BMW i3, etc., have a range which is fine for the typical daily commute, and even for a lot of delivery services.  But recharging in most cases can only be done at 20 miles of range per hour.  But for occasional longer trips, they remain a problem, and you have to spend several hours on the charger for every hour you drive.  Not adequate if you're taking a trip that's substantially longer than the range of the battery.   So far, Tesla has the most complete solution: 1) a much bigger battery than the others, giving 250+ miles of range.  2) faster "destination" charging, as much as 60 miles of range per hour, so you can put those 250 miles of range on in only 4 or so hours, allowing two or three cars to use the same charger over the course of a night, and finally, the Tesla "supercharger", which can put 150  miles of range on 20 minutes.  Presently, these are located about 150 miles apart on most of the big cross country routes in the US, but there are still a lot of gaps.   Tesla has promised to get around to them, but it'll be a while.

The second best solution is to make some sort of fuel-electric hybrid.  there are a number of plug-in hybrids available, but all have a very short range.  If your commute is very short and you're careful to plug in every night, it may work for you, but for long range travel, you're just a relatively efficient internal combustion engine car.

My idea is to put power rails along the roadway.   Whether these have inductive pickup or are actual physical rollers that run on rails is an engineering decision.  I'd put these on the interstates--the same routes where Tesla is putting its superchargers--and reserve a lane for them.   The new Teslas come with the ability hold lane, speed and following distance on their own (although lane following is still in alpha), and this is all it would take to have the car drive itself on an accurately delineated charger lane.   Many other carmakers have similar features available.  There is no particular reason that following distances couldn't be short and speeds high, as long as the computer is doing the driving.   The car will arrive at its destination city fully charged, and the driver rested.

The Tesla Model S charging at 19.2KW, charges at 60 miles of rated range per hour, so this is what it would need to maintain steady charge state at 60 mph at the rated characteristics.  This is probably all that's necessary.  The car draws less than that while going straight and level, but more accelerating or going uphill.  The battery can handle surges--the power rail is just for topping up.  It needs to be arranged so that all the cars needing to be charged can have their own charger.  Simplest would be for each car to tap into the same (say) 600VDC rail pair simultaneously and regulate itself so it never draws enough power to cause the voltage to drop more than a small amount.  If more power is needed, it reduces its charge rate and draws from its own battery.

Issues:
The power rails would probably need their own substation few miles or so.  Highly loaded, this would be 50 cars per mile or so. 19.2*50=960... a megawatt.   Those big, 200+ foot wind turbines put out 1.5 to 3 MW at their peak, so having one every  mile or so would work nicely when the wind is blowing.   A strip of solar panels along the road 6 meters wide (20 ft) would do the same thing when the sun is shining.  (there's a company that's trying to sell solar panels that work AS road surface...I think you could make this work by paving the special lane with such things)

If the power available is exceeded, the cars can run on their batteries, but they should probably be aware of what's happening.  If it's a traffic jam, they'd probably need to slow down and this will automatically reduce the power drawn.

600VDC with the availability to deliver 1600 amps would cause major badness to occur to any conductor that happened to fall across it, including a person or animal.  the conductors either need to be protected somehow, or buried with inductive pickup.

there should probably be some mechanism to keep non-robodriven cars out of the special lane.   I think the double white lines and reflective bumps as used on toll lanes, are not quite enough.  There is no real safety problem with illegal use of a toll lane.  There is with power rails and high-speed robocars,

billing should be straightforward.  the car would have a tamper-resistant meter which monitors the number, location and timing of watt/hr picked up and communicate it with substation, which would bill appropriately, and prevent incorrectly equipped cars from driving on the road.  If it becomes a problem, substation can monitor load and correlate it with the traffic data to detect tampering.  I suspect it won't be...once the roadside infrastructure is built, it'll last for decades and cost very little to maintain.   It'll pay itself off in a few years.

heavy trucks should be able to use this.  they'll obviously draw more power.  the road design can handle this straightforwardly.  more megawatts per mile.

because all the cars are robodriven, including the heavy trucks, all the vehicles will run down exactly the same part of the road, and rutting will be a worse problem than it will be on roads with human drivers.   Since there's a parallel road and all the vehicles have batteries, repairing it will be pretty much the same as with present roads.

Electric Car Chargers

Electric cars have finally crossed the line from being futuristic possibilities, through hybrids that exploit some of the benefits of electric power but still burn petroleum, to fully electric vehicles.  Tesla and Nissan are the big trendsetters, but now pretty much all the carmakers are on board.

Charging an electric car presents some special problems, mainly stemming from the fact that moving the mass of a car (and passengers) requires quite a bit of energy. Gasoline (and its relatives) have tremendously high energy density.  The breakthrough that's made electric cars finally feasible is the lithium ion battery, which is both smaller and lighter than it's predecessors.  But it still takes much longer to charge a battery than it does to fill a tank with gasoline.

Broadly speaking, there are three types of charger that have evolved, which go by the name "Level 1", "Level 2" and "Level 3".   The first two are not really chargers, but EVSEs "Electric Vehicle Service Equipment".  They just pass the power unchanged, with the addition of some safety equipment.  The charger is on the car.  A level 1 EVSE uses one phase, line voltage power.   In the US, this means 120V, 15 or 12A.   The SAE definition is that a level 1 EVSE is single phase and not capable of charging at faster than 1920W.  A level 2 EVSE is 2 phase, 208 to 240V and may go at up to 80 amps, but very few of them actually do that.  This is a theoretical peak of 19200W, but very few go higher than 7800.   "Level 3" is not defined, but in practice, it's anything that goes higher than 19200W.

The standard EVSE system is SAE J1772, which defines a 5 conductor connector, which has two power conductors, a ground, a "pilot" and a "proximity" conductor.  The latter are used for safety signaling.  The "pilot" carries a 12V 1KHz square wave which is used to detect continuity, and the "proximity" signals to the car that it's plugged in, and blocks the vehicle from being driven until it's disconnected.   Power is just passed through on the three power and ground conductors, but a relay opens the circuit unless pilot and proximity are deemed valid.  The idea is to make it impossible to charge a car with a kludged up power cord, just the sort of thing that might start fires, and to reinforce it, they tell you not to use extension cords when you buy the car. Virtually all electric and plug-in hybrid cars support J1772, although a few, such as Tesla S, require an adapter.  (Tesla exploits their incompatibility to use the same conductors for their "supercharger" level 3 scheme.)

The electric code also requires that lines being heavily loaded for more than half an hour only carry 80% of their design capacity.  This is also to prevent fire--heat builds up gradually, and your charger is likely running while you're sleeping.  This is the reason that a charger wired for 15 amps is only allowed to draw 12, 50 amps only allowed 40, and so forth. 

Level 3 chargers typically use special power arrangements to draw more than 80 amps.  Generally they are called DC chargers but that oversimplifies what they're doing.  They require smart electronics and high power connectors--generally beyond the capacity of home chargers The three main protocols are the still evolving J1772 level 3, the CHAdeMO, and the Tesla Supercharger.   The first two require a very special connector, while the Tesla uses the same connector as level 1 and 2.  (this is the main reason Tesla went its own way rather than allowing J1772 to plug in directly).  BMW and Nissan tried to negotiate a license to use the system during summer 2014, but BMW recently announced that it's building its own network of level 3 chargers using the J1772 "combo" connector, which is a kludge involving a J1772 and a separate, higher capacity connector in the same plug.

Big Vehicle vs Small Vehicle Transit

Prior to the invention of the steam engine, all peoplemoving was done with small vehicles.  Horses, small wagons, your own two feet, etc.  The steam engine and its internal combustion relatives made it possible to go much faster, and to carry more people at once.   Until about 1910, most of these machines required a highly expert operator, who was expensive, so there were economies to be gained by going with bigger vehicles.  Even the earliest streetcars, which were powered by a horse and driven by a person with an expertise that was commonplace at the time, were larger than the normal vehicles used to move people and goods.  Consequently our notion of Mass Transit came to be affiliated with big vehicles.  To be economical, big vehicles and their drivers must operate on a schedule, on a predictable route.  Nearly all go back and forth on this route.  This is called line-haul transit.  Trains, trolleys, monorails, buses etc., all use the biggest vehicle practical and operate on a line-haul route on a schedule, even when the driver is a computer.

Meanwhile, pedestrians, horses and eventually bicycles and automobiles move far more people.  These are unscheduled, take their rider(s) from one point to another and nowhere else, and are operated by one of their riders.  Because their operator is unpaid, an automobile's actual operating costs per passenger-mile, when everything is factor in--road construction costs, vehicle costs, etc., are about the same as the cost of a bus and cheaper than most railed transit.  If you can afford one, they are much more convenient, but they generate lots of problems: congestion, pollution, paving of large areas for roads and parking, consumption of non-renewable resources, etc.

Big vehicle transit is only cost effective when something forces the price of small vehicle transit to be really high.   Most often this is congestion.  Our biggest cities are so dense that congestion causes travel by automobile to be nearly as slow as walking, and it's extremely difficult and expensive to find a place to park.  This forces people to use transit, and as a consequence, transit routes serve a lot of areas and schedules are such that most people can function well without a car.  Taxicabs and limousines serve the high end and can be time-savers for those that can afford them...someone else is paid to deal with the parking problem.

I'm only aware of one form of transit that has the unscheduled properties of cars and taxicabs, the short trip times of subways, does not pollute, does not require large parking areas, and is as cheap as buses running on roads.  It is called Personal Rapid Transit.  Small vehicles, grade separated, offline stations where the vehicle waits for passengers, computer controlled.  Because it's non-stop, it'll get you there faster than the subway or private car in the city.  It's electric powered, so it doesn't pollute.  The vehicles are small enough that moving them for a single passenger doesn't waste much energy, but special vehicles to move groups can be provided.

Elevator Speech for PRT

This is really a little too long for an elevator speech, but I don't think you can capture the power of Personal Rapid Transit in 30 seconds, but here's a try.

PRT is elevated, uses computer controlled small vehicles, with offline stations. Vehicles wait in the station for passengers (in most transit, people wait for vehicles), and go line speed, non-stop, the whole trip.  The vehicle is small enough that there's no need for schedules--a single rider is enough to move it, so there's no waiting, anywhere, unless demand is so high that lines develop in the station. Because everything is light and small and top speeds are moderate, structural loads are moderate, which means the guideway can be light and small--and cheap. Not as cheap as a ski lift, but not too far behind, and a lot more useful.

Our design uses an on-board switch, which means we can run the vehicles arbitrarily close together (where a train has to move big pieces of rail to change routes--no closer than about 30 second headway and most require 3-4 minutes). Simulations on complex systems suggests that capacity with 1/2 second headway tops out at about 5000 Vehicles Per Hour Per Direction--about 5/7ths of perfect. With a 3 passenger vehicle, this means 15000 PPHPD. Central LINK peaks at 4000 PPHPD with 6 minute headways at rush hour, and the busiest subways in the world can only manage 25K with 2000 passenger trains, cost 10 or 20 times as much and take a lot more space.

Our company hasn't sold a real one yet, but we have a full size working prototype, a 1/8th scale test track, and by far the most sophisticated simulator that I'm aware of anywhere in the transit world.   Three of our competitors have systems running, all much lower capacity than our design: Morgantown, WV; Heathrow Terminal 5, London; Masdar, Abu Dhabi. (Masdar is almost comically incompetent--we helped with initial planning, but then they went with a lowball bidder, who really couldn't pull it off. Morgantown's been working almost flawlessly for 30 years, Heathrow for 3.)

None of these systems demonstrates the real power of PRT, which is that the system is arbitrarily expandable and benefits from network effect.   We are unaware of any theoretical limits to the capacity or scope of the Skyweb Express design, although there are lots of ways that bottlenecks can be created...system design and simulation is important.    I have done several simulated layouts with over 250 km of guideway, 175 stations and 5000 vehicles...it's pushing the capacity of a 3GHz processor, but our design is highly distributed--only optimizations are centralized; all actual control is localized.  I believe that in the long term, PRT will completely replace municipal buses, trolleys and subways--basically anywhere population density exceeds about 5 rides per day per acre.

Seattle activist group: www.gettherefast.org 
Our company: www.skywebexpress.com

Types of Electric and Hybrid Vehicle

Ultimately, there are two ways to power a car:

Fuel, usually derived from Petroleum but sometimes agricultural sources or coal (namely Fischer-Tropsch), burned in an internal combustion engine, or Electricity, either generated in the car with an internal combustion energy or fuel cell, or stored in a battery--or both.  Since current batteries have low energy density compared with fossil fuel, all modern electric cars use various means to minimize or recapture electricity, most importantly, regenerative braking.

There are relatively few Pure Electric vehicles on the market although this is changing rapidly.  These must be charged by plugging them into a source of electricity.  The people with electrics I know seem to fall into two classes: about half have installed high power--7KW or more--chargers.  Tesla has a supercharger: 120KW, but as far as I know, nobody has installed one in their home.  The other half have not bothered.  They use ordinary 120V power to charge their cars and do not find it to be a problem.  In all cases, their daily commute is less than 15 miles.  (Most 120V chargers limit power draw to 1200W.  I suspect this is due to concern over sketchy wiring and long extension cords.)

Pure Electric cars include the Tesla (all models), and Nissan Leaf, the Smart ForTwo EV, quite a few others.  The runaway success of the Tesla has provoked nearly all the big carmakers to follow suit.   Most have range well under 100 miles, although the Tesla can go over 200.

The most common type of EV by far right now is the Parallel Hybrid.  All of these can be powered either directly by the internal combustion engine or directly by the electric motors, running off the battery.  This involves a complicated transmission.  The IC engine can power both the transmission, and a generator.  Most are have fairly limited range and top speed under electricity.  the battery and generator are usually quite small.

Nearly all of the parallel hybrid makers are making or soon will make a Plug-in version, which allows you to top up the small battery.  They generally haven't added enough battery to give much all-electric range.  There is a substantial aftermarket for larger batteries and plug-in circuitry.

Parallel Hybrids include the Prius and related Toyota products, such as the Camry, the Ford Focus Hybrid, Most of the Honda hybrids, and quite a few others.  The Chevy Volt and the new Cadillac ELR are technically Parallel Hybrids although they are mostly Series Hybrids.  I'll get into this later.

A Series Hybrid is mostly a pure electric vehicle, but it carries an on-board engine and generator.  This is much simpler and more efficient than a parallel hybrid, but for some reason, most of the carmakers didn't go that way.  I think they were concerned about the size and reliability of batteries when the first hybrids were being introduced.  The power of a series is constrained mainly by its battery: a bigger battery means you don't need as big an engine. 

The most important series hybrid on the market, the Chevy Volt, was apparently felt to not have quite enough oomph going up long hills, but instead of improving the battery, they put in a bigger engine and made a clever clutch device which engages the transmission with the engine when the electrics weren't enough.  This technically makes it a parallel, but as long as the clutch isn't engaged, it's a series.  I believe most buyers of Volts would have preferred to have less power on hills and longer electric range.  Most of my friends who own them rarely if ever drive fast or far enough to engage the engine.  The new Cadillac ELR uses the same mechanism.

GM has another variation, which they've dubbed a Mild Hybrid.  This is an entirely normal internal combustion car, with an oversized battery and starter motor, and a small amount of extra electronics.  When you stop the car, at a traffic light for example, the engine stops.  When you press on the gas pedal, the starter starts the car moving while it's restarting the engine.   I don't think any of them bother with regenerative braking or pure electric while driving at low speed, but if you spend a lot of time idling, this could be a fuel saving.  But it's mostly marketing.

A solar powered car that resembles the performance and comfort of today's cars is impossible.  Noonday equatorial sun on a clear day is about 1000W/square meter.   The total surface area available for exposure to the sun is about 7 square meters on the typical car.  Due to inefficiency, and the fact that most of the time it isn't noon on a clear day, and most of us don't live near the equator, that means we have an average of about 500 watts if the sun is up.  That's about 2/3rds of a horsepower.  even if somebody came up with magic 75% efficient solar panels (today's best are under 40% and most are about 15%), that would only bring it up to about 5hp...still not enough.   But that doesn't mean you can't use solar panels to help recharge the battery of your plug-in.

Flying Cars

When people hear about my support for Personal Rapid Transit, they sometimes compare it to the Jetsons or wonder about Flying Cars.   Unless there is a pretty significant technological breakthrough, I'm pretty skeptical that flying cars will ever happen.

Let's pretend for a moment that the breakthrough occurs and a car can be made to take off and hover without the huge energy expenditure that doing that today requires.  (This might be a breakthrough in anti-gravity, but it's more likely a new, very cheap, very portable source of energy.).  This doesn't change the need for roads, although the new technology would allow them to be in the sky.  Presumably this would mean that they could be built very cheaply, and that they don't interfere so much with other construction.  If more capacity is needed, they could be easily widened or extra decks added.  They are still plainly finite and subject to traffic jams.  Many science fiction movies with flying cars, such as Blade Runner, Star Wars, etc., have recognized this and show nearly all the cars moving in neat rows.  The action of the movie often involves a breakdown in this order but if such disorder were commonplace, flying cars would either crash into each other constantly, or have to stop to avoid such collisions almost as often.

NASA and the FAA have been working for some years on a "NextGen" instrument navigation system, sometimes called "Highway in the Sky".  Early stages of this amount to technological improvements to present instrument flight systems--automated radio frequency handoffs, altitudes and headings transmitted directly to "glass cockpit" navigation systems, etc.  If limited to present instrument routes, it wouldn't have much impact on system capacity, but it would substantially reduce workload and errors for instrument pilots.  But over the long term, it would allow many more routes to be managed.  But without cheap VTOL and hover, the runway would remain exactly the bottleneck it is with aviation today.

Cheap VTOL changes everything.  The "road" could be above the scene, and when you need to stop, you simply leave the road and drop down to whatever your destination is.  Present VTOL and hover consume a tremendous amount of energy.  Present technologies, which are aerodynamic, also require substantial space between vehicles.

---

Interestingly, Personal Rapid Transit allows a bit of an approximation:  As with flying cars, the "roads" are elevated, so they don't consume much real estate on the ground, and can easily go over or around obstructions and other routes.  They're a lot cheaper than other forms of railed transit, although not so cheap as simply reserving a corridor of air.  And you can add a station anywhere you want, without interfering with traffic.  Transportation with PRT is a lot more like taxi service than having a private car.  Like the movie versions of flying cars, the vehicles can run very close together and move a lot of people.  And because they are on fixed guideways, it's very difficult to make them collide.