Please create an account to participate in the Slashdot moderation system


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 Internet speed test! ×

Comment Re:Reasons why I don't like Musk's hyper loop (Score 1) 124

First, the only way the hyper-loop or any other very high-speed, high-efficiency transportation system can possibly work is in a low-drag environment. The only way to establish low drag is to lower the air pressure. There aren't windows because the vehicle is in a tube that's been depressurized. If they reach the target speed of 700 mph, windows wouldn't help regardless. The terrain would move by so quickly that it would be nauseating and disturbing to most people inside. Even on high-speed trains, like the AVE in Spain, it can be difficult looking out the window for any length of time.

The way you would alleviate discomfort would be to have large displays that could show something interesting, sort of like the elevator that was built for tourists at the One World Trade Center. Or perhaps fit people with VR goggles. It may not work for everyone, but transportation systems can rarely perfectly accommodate the entire population. Many people refuse to fly due to a fear of heights, fear of crashing, discomfort with security screening, etc.

I'd presume they would always know where pods are located within the system. The pods are self-powered and would surely have emergency backup systems. In addition, they'd probably have spare pods that could operate within the tube at a lower speed for the purpose of towing or pushing stranded pods to access points. That might not even be necessary if they space the access points regularly enough. The pods would surely have a very long stopping distance and could be programmed to vary the amount of braking pressure to have it stop at or near an access point. They'd likely have bulkheads every mile or so in order to be able to service the tunnels without needing to pressurize the entire route. Those bulkheads could be used to isolate a section of track and quickly pressurize it.

None of these are insurmountable problems. But they will take time to develop and test without a doubt.

Comment Re:Watch the road! (Score 1) 215

I only have anecdotal evidence, which of course isn't convincing but finding accurate statistics on this isn't easy.

When my dad was a teenager, he sneaked out of his parents' home then came back early in the morning (at 3am or so). His dad heard something and went downstairs, nearly shooting my dad thinking he was an intruder. He got rid of his gun the next day.

Even if you could find convincing statistics on accidental shootings, it wouldn't include the many close calls like that case.

I wouldn't mind owning a rifle, for target shooting or hunting. But if someone broke into my house, I'd rather have bear spray or pepper spray than a gun when confronting them. I think bear spray would probably be more likely to work (even if I miss, which isn't likely, being near the stream would probably disable the intruder), and I don't have to worry about killing someone (either the intruder or a relative), I don't really want to kill anyone if I don't have to. I've read many stories of people who have killed teenagers breaking into their homes who felt tremendous guilt later on even though they were legally defending their homes.

Comment Re:2 people (Score 5, Insightful) 215

My guess is because the license will be granted with the understanding that it's a research vehicle. Someone will likely want to be closely monitoring the output of the car's instruments, so this insures one guy can do that while the other focuses on the road.

If there wasn't this requirement, one guy could conceivably monitor the instruments and not pay attention to the road since the car is driving itself.

Comment Re:Google Beta (Score 2) 215

Google has been testing fully autonomous cars in the Bay area for years without any incidents. I would hardly call it 'beta' in the sense of beta software. There's also a requirement that two people be in the car while it's running. It's not as if Google will let hundreds of these cars out on the streets of Nevada with nobody inside to stop them. Not only will Google have $1 million in liability coverage, the lives of two of their own employees per vehicle will be on the line. I'm not too worried about them getting in accidents (at least not of their own fault).

Comment Re:I avoided all this... (Score 1) 529

Central heating with a modern furnace is much more efficient. I can't imagine how one would ever need 300 100-W light bulbs. I posted below an estimate showing that the same amount of work of those 300 bulbs could be done with 12 LED bulbs, using significantly less power (about 1/4th). Over the lifetime of the bulbs, you would easily save over $1000 using LED bulbs even if your electricity rate is as cheap as 0.12 cents per kWh.

Comment Re:I avoided all this... (Score 3, Insightful) 529

Using those 300 bulbs isn't free, unless for some reason you don't have to pay the power bill.

At .12 cents per kWh and a lifetime of 750 hours per bulb, it would cost you about $2,700 to use them. Tack on a cost of $1 per bulb, and you pay a total of about $3,000.

To get 750 * 300 hours of 100 W equivalent, you would only need about 12 of the LED bulbs. The cost of running them for that many hours would be $621. The article doesn't say how much the bulbs will cost, just more than $30. Let's double it to $60, then the cost of those 12 bulbs would be $720. You would end up paying a total of $1,321 for what would have cost $3,000 with incandescents, a savings of almost $1,700.

So it's your choice, either pay nothing down while paying more in the future, or pay more now but more than make up for it eventually.

Comment Re:Because Hybrids Don't Pay For Themselves (Score 1) 998

People often look at the increased price and don't consider that they will also like sell it at a higher price. I bought a Prius in 2008 and it has only depreciated about $6000 since then, which isn't a bad depreciation rate over that time.

If I were to sell my Prius today I would certainly come out ahead financially than if I had bought a standard hatchback in 2008 and were selling it instead.

Comment Re:Because everyone needs a gullwing suv (Score 1) 306

That's a very different car than the Tesla. Not all electric cars are equal just as not petrol cars are equal. None of the stats for the Leaf are in the ballpark of the Tesla.

Also, no cars are more efficient at high speed than lower speed no matter what kind of motor they use. Wind resistance is the main reason for fuel use above 30 mph or so (unless it's a monster car that gulps gas even when idling), and this resistance goes up with the square of the speed of the car. If the car is going 50 miles at 100 mph, it's doing a lot more work than a car going the same distance at 50 mph, so of course it will impact the range of the car if you're going faster.

Comment Re:Because everyone needs a gullwing suv (Score 3, Informative) 306

Probably not as bad as you would think. Electric motors are very efficient at giving high torque, while for a gas engine it's really inefficient when doing the same.

The assumption was a steady 55 mph, so is certainly the maximum possible range, so I'm sure the actual range would be less if you were driving in the city.

Comment Re:Good luck getting the protestors to support tha (Score 1) 744

I think you're misreading my comment. I argued that it's too late for tariffs. You seem to agree with me that tariffs are a bad idea.

I simply said, in response to the previous poster, that tariffs by China on our goods wouldn't matter because we export to them quite a bit less than they export to us. What does matter is just our own action of putting tariffs on products imported from China because Americans consumers would have no choice but to pay it.

Comment Re:Good luck getting the protestors to support tha (Score 1) 744

Why would we care? We don't export much to China anyway. On its face it would hurt them more than us.

At this point, it would hurt us too without a doubt. For most consumer products, there's no choice but to buy something made in China, regardless of tariffs. The time for tariffs would have been 20 years ago when we still had domestic consumer production.

Comment Re:Denial. (Score 2) 877

The rest is a mixture of pseudo-science and politics.

Fact is that nobody knows why the Earth is getting hotter.

No, the study of the Earth's climate is hardly a pseudo-science. It is a hard science based on observation, computational models, making hypothesis and testing them. There have been satellites collecting observations for decades, surface measurements for over a hundred years, and ice core samples going back thousands of years. We can directly observe the output of the sun on the surface as well as in space, the concentration of various gasses in the atmosphere, etc.

How in the world is that a pseudo-science?

There's politics involved because it would be expensive to try to take corrective action. The change would need to be done on a massive scale, which is going to necessarily require the involvement of governments. The ozone hole would have never been closed if not for the governments of the world agreeing to stop producing CFCs.

What amazes me is that people think we can't affect the climate when we just recently formed large holes in the ozone later, passed policies to stop it, and those policies worked and mitigated the ozone hole at the poles. Clearly, the actions of humans can have global impacts.

The next argument is that the climate is always changing. While that's true on a geologic timescale, it isn't for a human timescale. We have never seen such a sharp increase in the concentration of CO2 gas in the atmosphere, even going as far back as ice core samples allow. What non-human reason could possibly be behind such a sharp increase that has never before occurred? In addition, we have good estimates of how much CO2 is released into the atmosphere every year and this amount is sufficient to account for the increased levels of CO2.

Comment Re:First Anecdote! (Score 2) 633

That pretty much matches my experience with my Prius. The mechanic at the Toyota dealership told me that they still haven't had to replace the brake pads on any Prius (and this is at a large dealership in Boulder, CO that sees tons of Prius cars).

I also average about 45-46 mpg overall. I don't deal with too much congestion, but drive over big hills every day. The cold weather also hurts mileage.

Slashdot Top Deals

Where are the calculations that go with a calculated risk?