I think if they are doing a vacuum tube, they should get as close to a vacuum as possible.
I think if the USA is going to spend trillions on rail infrastructure, I think we should start with doubling or tripling the amount of trains on Amtrak first. It’s not as sexy as the Hyperloop, but it would get people riding trains more often
I think if we had an economy already built around these tubes it would be much cheaper, but I think that it would still be similar if not more in price as the building of highways.
It is not as easy as building a "bigger oil pipeline and running trains through it. The train moving at high speeds will need a complex and robust system that is continuous inside and outside the tube. The tube will also need ground foundation to handle those forces.
Curves and elevation changes will need to happen at even flatter grades than highways. The higher speeds mean higher acceleration around curves or up inclines. The less sharp turns means more of a reliance on raised structures and tunneling. Good luck on convincing thousands of farmers to put a tube through their property
Maintenance. A highway with a crack in it still works. A highway with a pothole in it still works. Maintenance on that pothole costs $10k USD and the highway is still usable through maintenance. Hyperloop maintenance would not be as cheap, the tube would be shut down before and during maintenance due to repressuring. The tube would need to be vacuumed again.
I’m sure there are other things undiscovered that would be costs as well.
I think the Hyperloop is a cool and shiny idea. In the US I would much prefer reliable and cheap, normal speed rail first, then highspeed, then Hyperloop if we ever get there. I don’t think we should be able to eat our pudding before we eat our meat if that makes sense.
As an American I am sad we don’t have currants here. Looks lovely though!
Hi, aerospace engineer here. As far as benefits go it depends.
If we assume the tube is constant volume and constant temperature. The ideal gas law says that in this case, the pressure would change proportionally with density. So if you lower the pressure by 50% the density should lower by about 50%.
Drag force is also proportional to density. So a 50% decrease in density will result in a 50% decrease in drag. This is true for subsonic speeds. The speed of sound is 343 m/s or 770 mph.
Drag also has a square relationship with velocity. So drag gets extremely high when there is an increase in velocity.
If we take the speed of the shinkansen(90 m/s or 200mph) as a baseline and lower the pressure by half. The new speed the Hyperloop would be able to travel with the new speed is 127m/s or 284 mph. That is faster 40% for the same amount the trains will have to work, but to build all of that infrastructure, spend all the money creating a lower pressure environment and maintain that pressure for thousands of miles is just not worth it. The vacuum tube is just not practical to make.
Edit: If you maintain a reduced pressure and increase speeds about 30% of the speed of sound, the subsonic equations I used start to be less accurate. But in that case drag increases dramatically in transonic and supersonic regimes.
Honestly, for growing places, or places with bad public transit, diesel busses are the way to go. They are the cheapest and require almost no new infrastructure so it can offset car emissions quicker than the other options. Established bus routes that are popular should be converted to tram lines or BRT.
It would be so wonderful if this is the last reddit hug of death
Chicago has a long history of segregation in the city. It’s worse than a lot of cities in the US. POC are leaving the city in droves because the city hasn’t well addressed the issues of the past. While I think wording it for pedestrian safety makes a lot of sense, this also makes sense in the context of Chicago
How much lavender did you add to the blueberry lavender cider?
I definitely tasted some sweetness but it is not as sweet as a lemonade or lime-aid. It could be back sweetened and be fine, but it wasn’t dry so I left it alone… The attenuation on the yeast was 70-80% and I’m sure the juice has some unfermentable sugars.
It is tart. Pineapple up front and lime aftertaste. The abv is around 5% so it is not too boozy. I’d say it’s pretty crushable
I call it hard lime-aid, similar to a mike’s hard lemonade brand drinks sold in America. I guess fermented beverageworks as well.
Great recipe!
Thank you so much! It shimmers in the sun!
I honestly disagree. If you can get 5 car users on a diesel bus, you are making a positive impact on the environment. And you can deploy way more diesel busses than electric ones. Once you build demand, you can skip busses altogether and replace with trams. The batteries in busses are a cool technology, but still exploit child labor and extended neocolonialism in the same way oil does. Also battery fires are much worse than normal fires.
I think we should electrify fleets as soon as possible but I think adding a few battery busses here and there won’t do anything but pander to environmentalist