Raytheon does GaN for RF application, not power conversion. They may have dabbled in power conversion but they're probably too expensive of a company to go after the commercial power conversion market.
Gallium Nitride has an extremely high melting point, it is usually grown at temperatures above 600C.
Back in the 80's they would have been talking mainly about Gallium Arsenide (GaAs) which is what enabled cell phone and wifi transceivers. Now silicon is taking much of that market back from GaAs since silicon has improved to the point where it is good enough for these applications and can be cheaper and more highly integrated.
Gallium Nitride got going in the 90's, being explored by the DoD for radar and other radio applications. In fact one of the goals was to just get better solid state drive amplifiers to drive really high power vacuum tubes. Now GaN is good enough to drive the radar directly (though tubes can still do some things that GaN can't).
Now that GaN has matured enough people are taking it into the power conversion market. EPC and Transphorm are two such companies with released devices.
Gallium Nitride (GaN) isn't going to be used for digital computer, rather it is being targeted towards power conversion circuits such as computer power supplies and motor drives. For these applications gate lengths are typically of the order of 1 micron which is child's play compared to the ultra scaled digital devices.
GaN's circuit size advantage is only partially from the reduced size of the chip, it is the fact that the GaN transistor can operate faster while producing less heat in power conversion circuits. Since the transistor produces less waste heat the heatsink is smaller. Since it can switch faster it means that the inductor and capacitor filter components can be smaller. All of this translates into much higher power per volume.
Did you watch the linked video? The Google car appears to smoothly come to a stop at a traffic light with two stopped cars ahead of the Google car. There's no "body language" that contributed to this situation, just a following driver who didn't stop in time at a red light with stopped cars ahead. It happens every day.
If you are about to slow down,... let off the gas a little bit
This is actually worse telegraphing than a smooth deceleration with the brakes because by just letting off the gas you start slowing down with no brake light signal to following drivers. It takes more time and brain power to parse that somebody is decelerating when they just let off the gas. At least for me when I'm following you.
If the Google car just enters a slowing-down event, it might be undetectable.
Again: brake lights.
It's not clear to me that the cube law is applicable. The cube law comes into play when all three linear dimensions (height, width, and depth) are changing by the same factor, so you are assuming that a width and depth (or girth) increase proportional to height increase is all healthy weight.
While this may be true it's something that needs to be examined in more detail to see how healthy weight is a function of both girth and height.
Wow, you're nitpicking very specific features of a system that doesn't even exist in prototype form yet.
1. Windows will no doubt be added so long as it is mechanically sound and doesn't endanger the passengers, and so long as seeing the landscape at such high speed so close to the ground isn't disorienting.
2. I'm sure before any people travel on this system (for which there isn't yet even a prototype) a safety analysis will be performed to see if an auxiliary air supply is necessary. They may well add breathing masks similar to what airplanes have for the event of high altitude depressurization.
3. Just because there's no indication yet of multiple "lanes" yet doesn't meant that there won't be.
The price of installed solar has dropped by half so new panels without the subsidy would have the same payback time. 8.8kW installed capacity at $3.46 per installed watt (as stated in the article) would now cost $30.4k.
While solar panels will not last forever they already pay back much more than their installation cost (even subsidy free) in much less time that you think. It is folly to compare the reliability of cell phones to solar panels.
You seem to just be looking for reasons to bash solar. Solar is not a silver bullet, there's no such thing yet. But it works and it's available now. And over the long term it more than pays for itself.
NASA develops very high-end solar panels for space applications where weight and energy are both at extreme premiums. This has little to do with panels being produced for residental PV.
Why so negative? This is a feel good article, and there's nothing wrong with that. It is pointing out quite rightly that solar has achieved a new milestone in adoption rate which is a good thing.
Yes it is well known that solar installed capacity does not correspond to generating capacity. And there is the problem of storing energy when intermittent renewable sources like solar become larger percentages of total capacity. But the solutions to these problems are available now if we choose to dedicate the resources.
Your numbers are also way off, solar has risen over 50% over the past year:
So yay. We went from half a percent to 0.51% total power input.
And oh darn. We maybe stayed around 20% at coal.
The correct numbers Source:
March 2014: Solar 0.4%, Coal 41%
March 2015: Solar 0.6%, Coal 33%
Most of the drop in coal usage came from the sharp uptick in natural gas. That same uptick is probably why solar outpaced coal. Solar is rising rapid though still very minimal, but accelerating the rate of install will get us to total renewable energy faster.
The above article points out that the cost is now $3.46 per installed watt, he installed 8.8kW, so today the same installation would cost around $30.4k (his out of pocket cost 10 years ago).
In other words the subsidies accomplished their precise goal of helping to jump start a solar panel and solar installation industry which now gives a payback time in the above case of about 10 years.
The Big Bang Theory is a superb example of this. It's treated as absolute and indisputable fact, yet it was never (and likely never will be) directly observed.
That's quite incorrect. The Big Bang Theory is treated as the best explanation that we have, for now, for explaining a combination of observations. I'm not saying that all middle school teachers get this subtle but important point across in their science classes, but rest assured that the scientists themselves are familiar with it. And if a better explanation comes along that fits the data better than the big bang then scientists will eventually jump ship to the better theory.
Did you find a good strategy for communicating with this kind of worker to avoid that kind of problem?
A lot of reviews are blind, but in several fields even in a blind review the fields are small enough and the reviewers sufficiently well read to be able to tell which group or individual is writing the paper anyway.
I don't understand why people who vaccinate are afraid of those that don't.
It's not fear, but there are several legitimate reasons to be concerned about people who choose not to vaccinate their children for personal non-medical reasons:
1) Some people have legitimate medical reasons why they cannot receive vaccines or it is harder for them to get vaccines, e.g. allergies.
2) Vaccines are not 100% effective but increasing vaccination rate provides greater protection to all.
3) We still care about kids who are not our own and we don't want them to catch easily preventable diseases like measles.