jnw2

``Lead On!'', by Rear Admiral Dave Oliver, Jr, 1992, claims otherwise on pages 50-51: ``On the day of interest, while operating at a deep depth, the digital-readout depth gauge on this ship stuck at a few feet shallower than the desired depth. As the submarine was not quite as light as the crew thought, the ship slowly drove itself deeper and deeper. No one recognized that the two other depth gauges were slowly creeping downward, correctly indicating that the ship was going deeper.''

There's a description before this of how 44 psi is 100 feet, and some of the depth gauges showed psi and others feet, and how the standard procedure had been to have the ballast tanks trimmed light, forcing a down angle to maintain depth.

The book continues ``We made several changes in submarines as a result of this incident. For one thing, we don't trim light and run with a down bubble anymore. If the ship takes a down bubble now, except during transitory conditions when the submarine is changing depth, then something is wrong.''

What's to prevent building a network with fiber to the home, with ethernet switches with 100 megabit ports for each home, and a 10 gigabit uplink on each switch going directly to a Netflix server? And is there any reason the per port cost of this ethernet switch should be any more than ten times the typical home ethernet switch?

Ideally, the last mile fiber would be divorced from the IP connectivity to the rest of the world, so that a residence would pay the same money to use that last mile fiber whether they're running 1 megabit or 1 gigabit. If you then had real competition for options from your central office to the rest of the world, you'd see performance for a given price increase dramatically.

I'd like to see the point & shoot camera companies start integrating complete Android phones into their point & shoot cameras.

I recommend submitting comments about this via the ``Contact us'' page on whitehouse.gov

I also think we should be encouraging the White House to put Bruce Schneier in charge of the TSA.

Looks like http://ycombinator.com/people.html doesn't list Paul Buchheit yet.

I think the right strategy for charging a locomotive battery pack would be to install a short section of 25kV catenary at the station/layover facility at the end of the route. Amtrak has some HHP-8 locomotives which are 8000 horsepower, about 5 megawatts, which demonstrate that carrying about 5 megawatts through a catenary system to a locomotive is not terribly difficult.

Recharging will take longer than refuelling a diesel, but if the recharging can be done in under an hour, that's probably tolerable.

Congress has

1) Only chosen to buy 20 Acela trainsets, with one first class, one cafe, and four business class cars each, and I believe four of those are always scheduled to be undergoing maintenance at any given time.

2) Told Amtrak to try to make a profit

Given the constrains of needing to somehow decide which people get to use the inadequate number of seats, and trying to make money, how do you kill two birds with one stone?

I see no reason you can't build tunnels 100-200 feet underneath people's homes to avoid kicking people out, but that has the problem that you need broad public support for spending that money. Then again, if we redirected 10% of our military spending to high speed rail, that would probably address the funding issues adequately.

The other thing is that greater superelevation would increase speeds possible through the existing curves. But as you increase superelevation, you potentially increase the minimum safe speed through that segment of track, and having 0 MPH be a safe speed is desireable. There may be some maglev derivative that could help with that problem. Rubber tires on concrete also have greater friction, which may allow them to tolerate a greater amount of unbalanced superelevation.

I thought the train equipment was a little lighter than that, and automobiles normally weigh somewhat more than 2000 pounds.

In any event, doesn't the train being heavier mean that it can carry a much bigger battery pack than the automobile?

Amtrak's newest diesels produce 4200 horsepower, which is just over 3 megawatts. 40 Roadster battery packs (at 53 kilowatt hours per battery pack, and about a thousand pounds per battery pack) would store roughly 2 megawatt hours (35-40 minutes of the diesel at full throttle), weigh 20 tons, and probably cost something under $2 million at Tesla Model S era pricing. The catenary locomotives Amtrak is buying are over $6.6 million each, so the cost to add batteries sufficient for Richmond or Springfield service might well increase the cost of the locomotive by less than 50%.

Most parts of the world have found that the current three hours from DC to NYC is already short enough to eliminate the flights except for people connecting to other flights. However, Amtrak doesn't have enough seats to absorb all the airline shuttle passengers.

The really interesting thing about a 90 minute or better Boston to New York City trip is that it opens up the possibility of daily commuting. It would also have the potential to add places like Springfield and Hartford to the set of suburbs of Boston and Manhattan. But Amtrak seems content to plan on that not happening for another 30 years.

http://en.wikipedia.org/wiki/Keystone_Corridor seems to think electrification to Harrisburg was completed in the 1930s.

Amtrak has shown no evidence of planning to use batteries similar to what is in the Nissan Leaf or Tesla automobiles for the Richmond-DC or New Haven-Springfield portions of the Northeast Regional runs, instead apparently planning to continue to swap between diesel and electric locomotives at DC and New Haven. There should be plenty of battery powered cars on the road that can cover far longer ranges than DC-Richmond or New Haven-Springfield by the time Amtrak starts taking delivery of these locomotives.

Having enough seeking bandwidth across 7200 RPM or 10K RPM or 15K RPM bottlenecks sometimes contributes to not being able to use 1 TB 7200 RPM disks in enterprise file servers with acceptable performance, but needing more expensive (per GB/TB) options.

Then there are the costs associated with backups.

Not that this necessarily explains away your complaint entirely.

I'm not sure I agree with the objection to passwordless ssh keys. A system that uses passwordless ssh keys may be more secure than one using an unauthenticated protocol.

I suspect oil prices are going to collapse at some point in the next several years, once there are enough battery powered cars on the roads from Tesla and Nissan and others to reduce the demand for oil a bit. That may have some effect on the economics of organic vs not-organic farming.

Of course, that doesn't make organic farming pointless. Some people are willing to pay for quality. If organic farming reduces water consumption, there is also the issue that there are parts of the country that don't have unlimited water supplies, and I don't know of any plans to dramatically increase the water supply, other than perhaps there being a small decrease in corn farming as battery powered cars reduce the demand for ethanol to dilute gasoline with.

An automated taxi service is certainly one of the things we ought to get out of this navigation technology (but you don't want to call it a taxi service, because you don't want to be subjected to the limits and fees placed on taxis by municipalities), but apparently if you look at commuter rail systems, you find that people tend to commute from suburbs to downtown in the morning, and back out in the evening. Commuter rail systems usually want to have separate overnight layover facilities on the outbound ends of routes, vs mid-day layover facilities in the downtown areas. You can force the cars to rack up empty miles, but it's probably more energy efficient to have separate mid-day and overnight parking.

The other thing the automated taxis should offer as an option is cars with multiple compartments, where if you wanted to get from one compartment to another you'd have to get out of the car. People who are impatient but don't care too much what their trip costs could request that they get one compartment of the car and it get routed so that they aren't delayed by other people in sharing the car, and then people who want cheap transportation and don't care so much how long it takes could book the other compartments. You could also have a hybrid option where the impatient would allow up to 5 minutes (or any number of minutes of the rider's choosing) delay to allow others to be picked up/dropped off, and there could be transfer points along major roads, and people wanting cheap travel could express a willingness to deal with N transfers. That could go a long way towards increasing the number of people in the average vehicle.

I'm not aware of any of the battery powered cars that have been announced being set up for battery swap.

Meanwhile, AFAIK everyone has agreed on a standard AC charging connector good for 120/240 V, with the connector itself being good up to about 90A (it looks like Tesla is using it with a 50A rectifier, and Nissan 30A).

Nissan's 80% quick charge in 30 minutes connector probably isn't quite high enough wattage to 80% charge a 53 kWH battery pack (as is found in the Tesla Roadster) in 30 minutes, and I think that 80% in 30 minutes may be the magic cutoff for claiming the $5000 California tax credit for buying one of these things, which leads to the question of whether Tesla will have an incentive to get quick chargers introduced which will be incompatible with the initial version of the Leaf.

(As a practical matter, I think if these chargers max out at 500 VDC at 125A, that's probably good enough for road trips, though higher wattage might be nice.)

If we manage to get cheap solar and cheap batteries, the usage pattern is probably going to be more like: top off batteries at work during the day, drive home, partially drain car batteries out to grid while the sun doesn't shine overnight, drive to work on what remains in the car batteries.

NIMBYism wrt adding new long haul transmission lines is likely to favor solar cells on many roofs if the cost of the solar cells come down enough.

I'm not convinced you need battery swap stations for personal vehicles.

The Nissan Leaf has a 500 VDC, 125A quick charge connector, which allows 80% charge of its ~23 kWH battery in a half hour. If you have a similar wattage charging option in a car with a 200+ mile range battery, it may turn out that the time that you will spend for lunch/restroom breaks in a typical 500 mile day of driving will be enough to recharge your battery enough, assuming you start the day with the battery topped off, and all of the restaurants and rest stops have charging stations. (But I suspect the restaurants will see early adoption of charging stations as a way to attract customers/advertise their business.)

The trucking industry may well benefit from swap stations, though. The Tesla Roadster is something like 1/4 or 1/3 battery by weight. The entire tractor of a typical tractor trailer rig is probably a bit less than 1/4 of the total rig by weight, and the tractor can't be 100% battery. This will probably translate to a somewhat shorter range.

On the other hand, at 60 MPH, wind resistance is probably what consumes most of the energy, and that is not strictly proportional to the weight as you scale up from personal automobile to tractor trailer.

There may also be some pressure on the busier roads to force the use of the automated mode, once it can reliably space cars closer than can safely be done with manual driving, and once a large enough fraction of the cars on the road support automated driving. (Presumably we will see a gradual decrease in following distance in automated mode, with lots of careful investigation of near misses along the way.)

I've found myself wondering if Google will solve the capacity problems from New Jersey into Manhattan faster than the new rail tunnel(s) that may or may not be getting built; the existing tunnels are pretty full, but it looks like Google has figured out how to dramatically increase the capacity of the existing road tunnels.

But the other question is how parking will work out. Certainly adding lots of parking spaces in Manhattan will be expensive. What will happen if there is an argument that New Jersey income tax revenues can be maximized by maximizing the number of New Jersey residents who can commute to Manhattan, and that the way to accomplish this with the lowest infrastructure cost to taxpayers is to allow the cars to drive themselves back to New Jersey to park for the day?

Once we have fully automated cars that obviously don't need the manual override features to be used, the spirit of the Americans with Disabilities Act says that it is unfair to deny those with disabilities that would prevent them from obtaining a driver's license the right to operate the automatic mode of such cars.