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James Douglas
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Also in the report is there would be wheels and electric motors for emergency movement once a stop had be commanded to get the pods to the designated escape points. these motors would be powered by the on board Li ion packs its an elegant concept. Maintenance of near vacuum in a sealed steel pipe is not that hard we transport natural gas and oil in sealed pipes by the millions of tons per year the only inflows of air would be at the station heads where the air locks are located and at the expansion joints also to be located at the station heads. the choice not to use hard vacuum is intelligent as commercial pumps can maintain the pressure chose for little more cost than semiconductor production levels of pressure. having a little air also allows air skis, and you can aerobrake in an emergency by just shockwave choking the airflow around the pod. loosing the compressor would be a big deal as the full air ram effect would slow the pod down very very quickly I could do the exact calcs but it would seem that the critical speed is near 200 mph for this level of air pressure and pod to pipe separation without an air bypass system the drag will be enormous and the pods will by laws of physics have to slow down if the compressor is turned off. the flip side is that since the compressor is designed to bypass 80% there is reserve to bypass 100% or more of the rated airflows in the event a breach happens therefore limiting the deceleration curves to safe levels. given that a full stop would take little more that 20 seconds at 2gs or so only the closest pod to a break might hit higher air density in that time.
In the report it is stated in at least three places that each car will have the means to emergency stop on its own without the linear motors this means some form of friction mechanical system at lower speeds and at high speeds just turning off the forward air compressor would cause the air to shockwave and choke on the front of the pod causing massive deceleration to the critical speed of the tube/pod separation ratio. more likely the compressor would be turned down to limit the decel rates to 2g or maybe 4 about the limit for eyeballs out g forces without injury. I had to get out my Ti85 but going from 700mph to 200 mph in 10 seconds would be 2.27G's to do it in 5 seconds would be 4.45g's going from 200 mph to zero over an additional 5 seconds would be 1.87Gs for a total stop time of 15 seconds from 700 mph to zero. The distance covered in those 15 seconds is a lot harder to calculate given 2 different deceleration curves...I hate calculus. Give the distance air could travel in a 15 second window of time from a complete section breach down the tube the likely hood of ANY pod encountering that increased density falls. This time could be reduced to 10 seconds using a 4g and a 1.8G curve. 700 mph is 1026 feet per second the max distance over 15 seocnds would be 15400 feet at no deceleration or 2.91 miles since each car is over 10 miles apart there is no way a single breach or stopped car could hit each other. Losing the air cushion is improbable as the cars carry an internal bottle of air just for that purpose should the compressor fail the emergency breaking system needs 20 second at most of air to bring a car to a complete halt. I used the 1.8G 200 mph to zero figure as that is what aircraft tires are rated at in friction coefficient carbon fiber pads on steel walls would have a much higher friction coefficient think brake pads on a disk in your car you can easily lock the tires up and skid the tires are the lowest friction member out that system.
another point to make is that with a intentional breach as the air flows up the tube towards the lower pressure in the unbreached portion of the tube the farther from the breach up tube you go the more the friction on the in-rushing air. since the diameter of the tube is so small compared to the length the friction would be enormous a short distance from the break, a few miles at best after that point the wall of air would be drastically slower moving than in the initial breach mode. given that each pod would be 30 or so miles apart only one may be two pods would be close enough to any breach to feel the effects at full speed the rest would have slowed to subcritical speeds and be using emergency motors to get to an escape point which if you read the report would be scattered along the routes. Given the number of people who just died when a train derailed due to operator error , risking the lives of 24 people to an intentional breach which would have to be terrorism seems to be an acceptable risk and even then a stout emergency breaking system would probably save the closest pods people as well.
The diameter of the tube vs length is what matters if a sudden break such as an intentional breach was to occur air can only flood in from the open end of the breached tube and then down it's length if you read the report there would be pressure sensors all along the route any breach would be almost immediately noted and all cars in the tube would be commanded to emergency stop. a 2-4G breaking would lower the speed from 700+ mph to under 100 in a few tens of seconds and individual pod would most likely never encounter the much denser air wall rushing down the breeched open tube. If there was a pod that happens to be close enough to the sudden breach that its emergency stop could not slow it the choking effect of the air piling up in front of the pod and between the tube would slow it drastically probably at 6-10G over a few seconds this is survivable for most healthy people I personally have pulled 10gs as a younger man and 6+Gs in sport aircraft in my 30's
In this part of the OCS there are massive oil and gas reserves as well currently offlimits to production. The methane hydrate reserves are mind staggering the successful hydrate production testing by the Japanese prove that methane hydrates can be stimulated by depressurization or gas/gas replacement for production of CH4. The East Coast OCS is known to have some of the worlds largest methane hydrate deposits second only to the Gulf of Mexico literally thousands of years at our current consumption rates.
Get this to Tier 2 bin 5 EPA specs and bring it to the USA I would buy one cash at $33K but to hit T2B5 would take SCR and Urea injections plus an DOC cat i'm guessing it already has a DPF for Euro6 adding all that emission control will suck 10mpg at least off the figures. still high 50s real world in the engineering and style of an Audi yup I would buy one cash on sight.
Another point is the Canadians are planing pipelines east and west to deep water ports that need no dictator wannabe approval these pipelines will be constructed and when they are this oil is going to China and will be super tankered to the Gulf of Mexico anyway the tanker cost from the St Lawrence ports to the Texas / LA refineries will still be lower than Venezuelan heavy oil. The US side of Keystone to Cushing Ok and from there to the gulf coast is being built regardless of dear leaders approval he has no say in state to state pipelines and the Bakken oil will flow down those pipes regardless. The biggest benefactor to stalling the keystone pipeline has been the rail companies primarily BNSF...who's owner is also a huge contributer to dear leader go figure. My dad always said follow the money there you will find the truth.
" Instead of replacing the bitumen with heavy crude oil from Venezuela replace it with cleanly generated electricity!" Show me a economically competitive vehicle that can use clean electricity instead of petrol or diesel. This vehicle must have a none stop range of 400km without recharge and a lifespan of at least 200000km and be on equal terms in total cost of ownership with a identically sized ICE vehicle in payload and passenger capability. Heavy crudes are not used to make electric power they are visbreaked and hydrocracked to Jet A , #2 Diesel , and Petrol which 90+% of our vehicular fleets use the few true EV on the road all have less than 200km ranges and sacrifice passenger and payload capability. Ok the Tesla but the average person is not going to buy a 80k ev. The 35K price range EV's are all tiny underpowered under ranged glorified golf carts for 35K one could get a new Audi or BMW with no limitations.
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Jun 15, 2013