E-bikes will stall for one simple reason: the car lobby will make sure wide spread adoption will not be possible. They will introduce 'safety' laws to 'protect' E-bike riders from those 'dangerous' speeds up to 20 mph. You will need to wear a helmet, pass an exam (and will be re-examinated verey year if possible), pay taxes and a liability insurance for when a car crashes into you^H^H^H^H^H^H^H you crash into a car.
Donald Trump will declare riding a E-bike is un-American, wasn't invented here, and will forbid them when hes is president.
Self driving cars will be a lot safer for bicycles, pedestrians and so on. The software in the car is always vigilant and will actually see them and stop for them. Their awareness of other road user might be their biggest problem. People just will take priority of self driving cars because they know the car will stop in time to prevent an accident.
Exactly. It is far more better to spend this amount of money defending the oil interests in the middle east. Big oil and the weapons industry made billions. So that is 100% OK! Money flowing the right direction. Why spend this amount of money in science? No one has interests in science!
These are her suicidal problems but that wasn't a problem according to the DHS. Her hospitalization for clinical depression in 2012 was. That is nowhere mentioned in the links (the book is from 2009).
I am using a ReadyNAS Duo running Free BSD. The NAS is in a cupboard a a friend a few houses away.
For syncing I use Unison. The initial backup was created onsite. Every night I run an incremental backup. When local drives are destroyed it is only a short walk to get my data back.
GP has already used all the supposed finite number of prime numbers in constructing his contradictory bigger prime.
The proof constructs a number that is not divisible by any of the prime numbers in the set of all prime numbers. Therefore it proofs there are an infinite number of prime numbers. The conclusion the constructed number must be prime is wrong.
The Greek knew in 300 BC there are an infinite number of prime numbers. The same proof also shows the gab arbitrary between two numbers can be arbitrary large (even larger as 70 million).
This proof shows there are an infinite number of primes that are 70 million or less from each other.
If the US companies are stalling this development I bet soon enough some Japanese or Chinese companies think is is a great idea and start selling it all over the world. Just like electric cars, pv solar cells. US companies may even try to block import of those great power supplies and make the US into some backward country where they are still burning fossil fuels for energy while the rest of the world moves on.
To accelerate a 100000 pound object to 240 mph requires an energy of 260 MJ (sorry I converted all units to SI before I started calculating so you have to convert it back to BTU or kcal or whatever the right unit for energy you want to use yourself). Assuming a linear acceleration over 300 feet to 240 mph gives an acceleration time of 1.7 s. This results in an average power of 153 MW. AFAIK there is no electrical turbine that will supply an extra 153 MW at the flip of a switch. Electrical energy has to be stored somewhere to let the catapult work.
They run at gigahertz speeds, which implies nanosecond timings. A flywheel with decent mass spinning a million RPM is only four orders of magnitude away from the speed of light. It all depends.
Speed of light: 300e6 m/s Speed of micrometer scale graphene flakes spinning at 60 million rpm: 2*pi*1e-6/1e-6 = 6 m/s = 21.6 km/h I think you can get any material spinning at 60 million rpm at micrometer scale. Tensile strength is not very important at these speeds.
Genes determine what is possible. But the environment determines whether these possibilities actually happen. In case of height I think food is very important for the expression of the genes.
At the moment I think it's aimed at typical commuting distances. 360 km is a very long ride! (How long does that take?!)
Actually it is close to 400 km (A120, A12, London city center, A4, A30, A303). My best time is 14 hours, worst 20 hours. For the return journey I allot 24 hours because I don't want to miss the ferry. But 400 km isn't that a big distance when you train for rides like Paris-Brest-Paris or London-Edinburgh-London.
Even in the Netherlands we do not have a satnav app for cyclists on the iPhone. Route for cyclists can be done by the excellent 'fietsrouteplanner' planner from the Fietsersbond (http://www.fietsersbond.nl/fietsrouteplanner/fietsroutes-vandeurtotdeurplanner/index.html). This great planner has lots of options and biker profiles (like shortest route, avoid busy traffic, green route, social safe route, racing cyclist, etc.) but once you are cycling it is quite useless. The route is static, has no rerouting when you choose an other route due to roadworks or just because you felt so.
I immediately tried out this app but was a bit disappointed. I cannot plan a route from Harwich to Exeter, a route I have cycled multiple times to visit family in England.
A single DiamonDisc costs $34.95, two or more individual discs go for $29.95, and a five-pack is $149.75.
Of course, the company is also happy to sell you its burner, but that will set you back $4,995. But, for $5,000 you get 150 DiamonDiscs to burn away until to heart's content. So one is $34.95, two or more is $29.95 per disc and a five pack bargain is $29.95 per disc.
But if you buy a $4995 burner you can get 150 disc for $5000, that is $33.33 per disc and you have to burn them yourself.
Back in the Roman Empire days, they could communicate with Rome using towers built on each others horizon. They then used light codes (similar to morse) to then relay information back to the Caesar. Semaphore towers were only invented in the 18th century. The Romans used couriers on horse back to send written messages. And according to rhe Wikipedia: In about 35 AD, the Roman emperor Tiberius, by then very unpopular, ruled his vast empire from a villa on the Isle of Capri. It is thought that he sent coded orders daily by heliograph to the mainland, eight miles away.
If Earth's solar constant is 1366 W/m2, and this 'color' absorbs 99.9% of the incoming light's energy (which wavelengths? all of them?), wouldn't this mean that it would be almost trivial to boil water in containers covered with this, and thus power steam turbines? Shouldn't this then be basically the solution to all out energy problems, or is there something i am missing?
Well, let us do some math on the trivial boiling of water with black containers.
Take a container with 1 kg of water. For ease of calculation we will take a 0.1 m x 0.1 m x 0.1 m container. Let us assume one side of the container faces the sun. Area is 0.1 x 0.1 = 0.01 m2 The staring temperature is 20C, boiling temperature is 100C. Delta t is also 80 C. Specific heat of water is about 4200 J/K/kg. To make the 1 kg of water boil you need 80 x 4200 = 336 kJ. Energy received on the side of the container is 0.01 x 1366 = 13.66 W. Time needed to get 336 kJ with this power is 336000/13.66 = 24597 s (=6 hours and 50 min).
Oops, not so trivial after all...
If you make a large area (1m2) container containing 1 kg water you need get a container of 1 m x 1 m x 0.001 m. This container would boil water in 336000/1366 = 245 s (about 4 min). Problem with such a container is a large area at the cool side of the container and the specific heat of the container is a lot higher than the specific heat of the water it contains. So you need to design a container with a very low specific heat compared to the specific heat of the water it contains, a large surface area to collect the solar energy and good isolation at the shade side to minimize heat losses. Welcome to the interesting world of designing solar collectors.
And for the very black material: going from 99% black to 99.9% black gives only (99.9-99)/99 = 0.9% increase of efficiency. The problem of solar collectors is not the black not being black enough. A new blacker black won't revolutionize solar collectors.
The "solar constant" is measured "on the outer surface of [the] atmosphere", most certainly NOT at ground level. Down here, you get around 100W/m2, during daylight, in the summer, with no cloud cover, etc.
You are wrong here. The 1366 W/m2 is indeed at the upper atmosphere. Lower in the atmosphere it is less, how much depends on the current state of the atmosphere. About 1000W/m2 is the right value.
The 100W/m2 is the energy output of a not so good photovoltaic module.
The theoretical maximum efficiency you can get from a heat engine is:
n = 1 - (Tc/Th) with: n = efficiency Tc = low temperature in K Th = high temperature in K
The tricky part of the article is IMHO: Based on the theoretical Carnot thermodynamic cycle, at 600 degrees efficiency rates approach 60 percent, twice those of today's solar Stirling engines. The builder of a solar Stirling engine can also claim without bending the truth: Based on the theoretical Carnot thermodynamic cycle, at 600 degrees efficiency rates of a Stirling Engine approach 60 percent. because a Sterling Engine can in theory reach the maximum efficiency, though in practice this is limited by non-ideal properties of the working gas and engine materials, such as friction, thermal conductivity, tensile strength, creep, melting point, etc. (quote from Wikipedia).
So he claims to have invented a heat engine that can in theory reach the maximum efficiency too. But what are his limitations by non-ideal properties of the working gas and engine materials, such as friction, thermal conductivity, tensile strength, creep, melting point, etc?
Slashdot Mirror
It shouldn't be at the poles. It should be quite hot:
I'm burning through the sky yeah!
Two hundred degrees
That's why they call me Mister Fahrenheit
Why does it take years to draft a standard?
Because the ITU made a plan how to get to the new G5 standard:
http://www.itu.int/en/ITU-R/study-groups/rsg5/rwp5d/imt-2020/Pages/default.aspx
Like this one form 2004?
https://tech.slashdot.org/story/11/01/03/1722240/researchers-claim-1000-core-chip-created
E-bikes will stall for one simple reason: the car lobby will make sure wide spread adoption will not be possible. They will introduce 'safety' laws to 'protect' E-bike riders from those 'dangerous' speeds up to 20 mph. You will need to wear a helmet, pass an exam (and will be re-examinated verey year if possible), pay taxes and a liability insurance for when a car crashes into you^H^H^H^H^H^H^H you crash into a car.
Donald Trump will declare riding a E-bike is un-American, wasn't invented here, and will forbid them when hes is president.
Self driving cars will be a lot safer for bicycles, pedestrians and so on. The software in the car is always vigilant and will actually see them and stop for them. Their awareness of other road user might be their biggest problem. People just will take priority of self driving cars because they know the car will stop in time to prevent an accident.
Nyh
Exactly. It is far more better to spend this amount of money defending the oil interests in the middle east. Big oil and the weapons industry made billions. So that is 100% OK! Money flowing the right direction. Why spend this amount of money in science? No one has interests in science!
These are her suicidal problems but that wasn't a problem according to the DHS. Her hospitalization for clinical depression in 2012 was. That is nowhere mentioned in the links (the book is from 2009).
I am using a ReadyNAS Duo running Free BSD. The NAS is in a cupboard a a friend a few houses away.
For syncing I use Unison. The initial backup was created onsite. Every night I run an incremental backup. When local drives are destroyed it is only a short walk to get my data back.
It all works like a charm.
But those nice guys in Geneva invented the WWW.
GP has already used all the supposed finite number of prime numbers in constructing his contradictory bigger prime.
The proof constructs a number that is not divisible by any of the prime numbers in the set of all prime numbers. Therefore it proofs there are an infinite number of prime numbers. The conclusion the constructed number must be prime is wrong.
Nyh
You now have a number that is divisible by none of the primes, which therefore must be a prime number.
Or the number is divisible by a prime that wasn't in you initial set.
The Greek knew in 300 BC there are an infinite number of prime numbers. The same proof also shows the gab arbitrary between two numbers can be arbitrary large (even larger as 70 million).
This proof shows there are an infinite number of primes that are 70 million or less from each other.
Nyh
If the US companies are stalling this development I bet soon enough some Japanese or Chinese companies think is is a great idea and start selling it all over the world. Just like electric cars, pv solar cells. US companies may even try to block import of those great power supplies and make the US into some backward country where they are still burning fossil fuels for energy while the rest of the world moves on.
She decided never to grow up when she heard her father declare that she would become a grocer.
Nyh
To accelerate a 100000 pound object to 240 mph requires an energy of 260 MJ (sorry I converted all units to SI before I started calculating so you have to convert it back to BTU or kcal or whatever the right unit for energy you want to use yourself). Assuming a linear acceleration over 300 feet to 240 mph gives an acceleration time of 1.7 s. This results in an average power of 153 MW. AFAIK there is no electrical turbine that will supply an extra 153 MW at the flip of a switch. Electrical energy has to be stored somewhere to let the catapult work.
Nyh
They run at gigahertz speeds, which implies nanosecond timings. A flywheel with decent mass spinning a million RPM is only four orders of magnitude away from the speed of light.
It all depends.
Speed of light: 300e6 m/s
Speed of micrometer scale graphene flakes spinning at 60 million rpm:
2*pi*1e-6/1e-6 = 6 m/s = 21.6 km/h
I think you can get any material spinning at 60 million rpm at micrometer scale. Tensile strength is not very important at these speeds.
It is a nice trick though.
Nyh
Genes determine what is possible. But the environment determines whether these possibilities actually happen. In case of height I think food is very important for the expression of the genes.
Nyh
At the moment I think it's aimed at typical commuting distances. 360 km is a very long ride! (How long does that take?!)
Actually it is close to 400 km (A120, A12, London city center, A4, A30, A303). My best time is 14 hours, worst 20 hours. For the return journey I allot 24 hours because I don't want to miss the ferry. But 400 km isn't that a big distance when you train for rides like Paris-Brest-Paris or London-Edinburgh-London.
Nyh
Even in the Netherlands we do not have a satnav app for cyclists on the iPhone. Route for cyclists can be done by the excellent 'fietsrouteplanner' planner from the Fietsersbond (http://www.fietsersbond.nl/fietsrouteplanner/fietsroutes-vandeurtotdeurplanner/index.html). This great planner has lots of options and biker profiles (like shortest route, avoid busy traffic, green route, social safe route, racing cyclist, etc.) but once you are cycling it is quite useless. The route is static, has no rerouting when you choose an other route due to roadworks or just because you felt so.
I immediately tried out this app but was a bit disappointed. I cannot plan a route from Harwich to Exeter, a route I have cycled multiple times to visit family in England.
Nyh
Ah, that was already done: a three color Lego plotter:
http://www.youtube.com/watch?v=Gue6GQ00Vi4&feature=fvw
The video is from March 2007.
Anyway it always nice to see people building less than trivial projects from Lego.
Nyh!
A single DiamonDisc costs $34.95, two or more individual discs go for $29.95, and a five-pack is $149.75.
Of course, the company is also happy to sell you its burner, but that will set you back $4,995. But, for $5,000 you get 150 DiamonDiscs to burn away until to heart's content.
So one is $34.95, two or more is $29.95 per disc and a five pack bargain is $29.95 per disc.
But if you buy a $4995 burner you can get 150 disc for $5000, that is $33.33 per disc and you have to burn them yourself.
Nyh!
Nyh
Well, let us do some math on the trivial boiling of water with black containers.
Take a container with 1 kg of water. For ease of calculation we will take a 0.1 m x 0.1 m x 0.1 m container.
Let us assume one side of the container faces the sun. Area is 0.1 x 0.1 = 0.01 m2
The staring temperature is 20C, boiling temperature is 100C. Delta t is also 80 C. Specific heat of water is about 4200 J/K/kg.
To make the 1 kg of water boil you need 80 x 4200 = 336 kJ.
Energy received on the side of the container is 0.01 x 1366 = 13.66 W.
Time needed to get 336 kJ with this power is 336000/13.66 = 24597 s (=6 hours and 50 min).
Oops, not so trivial after all...
If you make a large area (1m2) container containing 1 kg water you need get a container of 1 m x 1 m x 0.001 m. This container would boil water in 336000/1366 = 245 s (about 4 min). Problem with such a container is a large area at the cool side of the container and the specific heat of the container is a lot higher than the specific heat of the water it contains. So you need to design a container with a very low specific heat compared to the specific heat of the water it contains, a large surface area to collect the solar energy and good isolation at the shade side to minimize heat losses. Welcome to the interesting world of designing solar collectors.
And for the very black material: going from 99% black to 99.9% black gives only (99.9-99)/99 = 0.9% increase of efficiency. The problem of solar collectors is not the black not being black enough. A new blacker black won't revolutionize solar collectors.
Nyh
You are wrong here. The 1366 W/m2 is indeed at the upper atmosphere. Lower in the atmosphere it is less, how much depends on the current state of the atmosphere. About 1000W/m2 is the right value.
The 100W/m2 is the energy output of a not so good photovoltaic module.
Nyh
The theoretical maximum efficiency you can get from a heat engine is:
n = 1 - (Tc/Th)
with:
n = efficiency
Tc = low temperature in K
Th = high temperature in K
The tricky part of the article is IMHO:
Based on the theoretical Carnot thermodynamic cycle, at 600 degrees efficiency rates approach 60 percent, twice those of today's solar Stirling engines.
The builder of a solar Stirling engine can also claim without bending the truth:
Based on the theoretical Carnot thermodynamic cycle, at 600 degrees efficiency rates of a Stirling Engine approach 60 percent.
because a Sterling Engine can in theory reach the maximum efficiency, though in practice this is limited by non-ideal properties of the working gas and engine materials, such as friction, thermal conductivity, tensile strength, creep, melting point, etc. (quote from Wikipedia).
So he claims to have invented a heat engine that can in theory reach the maximum efficiency too. But what are his limitations by non-ideal properties of the working gas and engine materials, such as friction, thermal conductivity, tensile strength, creep, melting point, etc?
However it as a interesting invention.
Nyh