I am a physicist at the UK's National Physical Laboratory and I am involved in the redefinition of another unit - the unit of temperature. The work concerning the redefinition of the kilogram is >much more philosophically fraught and technically difficult. I understand many of the rather skeptical comments expressed here
The current situation is unsatisfactory because the mass of the kilogram is changing, albeit by a small amount - a few micrograms in 1 kg - i.e. a few parts in 10^9. The aim of the work is to replace this artefact with (essentially) a procedure.
Effort onne (using the silicon sphere) is essentially trying to build a link between a macroscopic mass, and the microscopic masses which we expect to be fixed.
The other effort not mentioned here is called the watt balance which is a machine which can exhibit the same inertial mass as a kilogram - or any other weight.
At the moment the two watt balances disagree with each other and they both disagree with the silicon sphere result. There is still a lot of work to do on both approaches.
Incidentally, the reason is it is a sphere rather than a cube is because of edges. Edges are amazingly fragile, hence the sphere.
ALl the best
M
As the richest corporation on Earth, I would kind of expect their products to be beacons of excellence. But they are not. I like their software tools, but Word? I use it obviously, but if I make a complex document with Equations and similar embedded, it crashes and I lose data. It >still happens and it simply needn't. So I don't really hate Microsoft, I just hold them in contempt for being dearer and poorer than they could be. I too think they will collapse within the decade. OK laugh but when it happens it will happen quickly.
This is all very nice, but then the scientist go and say this will 'help cool computer chips'. This it will never do, and I >hate itjust below the onset of film boiling (i.e. when this phenomenon does not occur) is well known to represent to the point of optimum heat transfer. Once film boiling comments, the heat transfer coeffiecient for the surface declines drastically (basically because the density of the coolant in contact with the hot surface declines). Although converting liquid to gas uses a large amount of heat for no rise in temperature, unless liquid can be kept in contact with the surface (by getting rid of the gas) then heat transfer declines
Making a droplet walk up hill is a neat trick, but in reality its like firing a water rocket with a payload of water.
I've been studying fuel cells of late and the one thing fuel cells can't cope with is changes in demand. So accelerating and decelerating (like you do when you drive) is just about >the worst application for fuel cells imaginable. They will have their application areas, but cars were not (and will not ever be) the area of choice.
As another poster mentions, bio-fuels are the way out of our current ecological mess, and the technology is available today.
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I am a physicist at the UK's National Physical Laboratory and I am involved in the redefinition of another unit - the unit of temperature. The work concerning the redefinition of the kilogram is >much more philosophically fraught and technically difficult. I understand many of the rather skeptical comments expressed here The current situation is unsatisfactory because the mass of the kilogram is changing, albeit by a small amount - a few micrograms in 1 kg - i.e. a few parts in 10^9. The aim of the work is to replace this artefact with (essentially) a procedure. Effort onne (using the silicon sphere) is essentially trying to build a link between a macroscopic mass, and the microscopic masses which we expect to be fixed. The other effort not mentioned here is called the watt balance which is a machine which can exhibit the same inertial mass as a kilogram - or any other weight. At the moment the two watt balances disagree with each other and they both disagree with the silicon sphere result. There is still a lot of work to do on both approaches. Incidentally, the reason is it is a sphere rather than a cube is because of edges. Edges are amazingly fragile, hence the sphere. ALl the best M
As the richest corporation on Earth, I would kind of expect their products to be beacons of excellence. But they are not. I like their software tools, but Word? I use it obviously, but if I make a complex document with Equations and similar embedded, it crashes and I lose data. It >still happens and it simply needn't. So I don't really hate Microsoft, I just hold them in contempt for being dearer and poorer than they could be. I too think they will collapse within the decade. OK laugh but when it happens it will happen quickly.
This is all very nice, but then the scientist go and say this will 'help cool computer chips'. This it will never do, and I >hate itjust below the onset of film boiling (i.e. when this phenomenon does not occur) is well known to represent to the point of optimum heat transfer. Once film boiling comments, the heat transfer coeffiecient for the surface declines drastically (basically because the density of the coolant in contact with the hot surface declines). Although converting liquid to gas uses a large amount of heat for no rise in temperature, unless liquid can be kept in contact with the surface (by getting rid of the gas) then heat transfer declines
Making a droplet walk up hill is a neat trick, but in reality its like firing a water rocket with a payload of water.
I hate this kind of story
I've been studying fuel cells of late and the one thing fuel cells can't cope with is changes in demand. So accelerating and decelerating (like you do when you drive) is just about >the worst application for fuel cells imaginable. They will have their application areas, but cars were not (and will not ever be) the area of choice. As another poster mentions, bio-fuels are the way out of our current ecological mess, and the technology is available today.