Being fat nullifies the advantage of being blonde.
Anyway, I agree, let's get back to the technology.
Being fat nullifies the advantage of being blonde.
She wasn't as massive when she started this. I guess some of that venture capital money went on fine foods.
(I use "massive" in the scientific sense of having the property of mass, I'm not saying she's a plumper yet).
Anyway, I agree, let's get back to the technology.
OK.
From what we've seen I don't think they have an awful lot, considering the time and $$$$$$.
I don't think there's any feedback in the calibration between the image detecting the white rectangle, and the 'beam forming', I get the impression that if the camera or TX array were off by a few degrees 'the beam' would be sent to the wrong place.
Being fat nullifies the advantage of being blonde.
This takes us back to the interesting "r^2" comment in the recent twitter spat (#913). Perry was correct in my view, to point out 1/r^2, and Matthew Ocko made quite the dick of himself trying to explain it away as Twitter-speak, a bit of a "covfefe" moment. Maybe it is Twitter-speak, but I don't see any other reference to it. Either way, clearly this spat wasn't his finest hour, not least by trying to erase it ever happened.
Perry was correct in my view, to point out 1/r^2,
Perry was correct in my view, to point out 1/r^2,She might have been correct in saying 1/r^2 doesn't count much for tightly focused beams, but she didn't say that uBeen were producing tightly focused beams.
Reminds me of the 2 or 3 last videos with the 2 prototypes, it was her that described all the conclusions, and told the reported what he had seen, just like a magician.
And I don't think any of the 'steerable beams' we saw in the videos were outside the normal beam of a US transducer, and as they're quite directional it's a problem.
As a theoretical question, I've seen some papers where the ultrasonic power transfer efficiency at 20kHz is 70-90%
As a theoretical question, I've seen some papers where the ultrasonic power transfer efficiency at 20kHz is 70-90%
As a theoretical question, I've seen some papers where the ultrasonic power transfer efficiency at 20kHz is 70-90%
Assuming a 16x16 or maybe 64x64 array, I doubt anything consumer-related can go higher than this.
Assuming a 16x16 or maybe 64x64 array, I doubt anything consumer-related can go higher than this.UBeam have been working towards a way to make arrays with thousands of elements "economical" but it hardly makes sense talking about what is economical in a consumer environment when they do not seem to have any technology that is practical in a consumer environment. This has always been a concept that needs the phone manufacturers lining up to integrate into their products and given that UBeam are now talking about maintaining the charge rather then boosting the charge, I cannot see why any manufacturer would even start to look at it.
My question was about the phased array efficiency, I can't find any data on that, much less on ultrasonic ones
This takes us back to the interesting "r^2" comment in the recent twitter spat (#913). Perry was correct in my view, to point out 1/r^2, and Matthew Ocko made quite the dick of himself trying to explain it away as Twitter-speak, a bit of a "covfefe" moment. Maybe it is Twitter-speak, but I don't see any other reference to it. Either way, clearly this spat wasn't his finest hour, not least by trying to erase it ever happened.Engineers generally refer to r-squared loses, not 1/r^2. What Perry said makes no sense. She said the r-squared issue doesn't matter with a tightly focussed beam, but r-squared loses apply regardless of the beam width.
This takes us back to the interesting "r^2" comment in the recent twitter spat (#913). Perry was correct in my view, to point out 1/r^2, and Matthew Ocko made quite the dick of himself trying to explain it away as Twitter-speak, a bit of a "covfefe" moment. Maybe it is Twitter-speak, but I don't see any other reference to it. Either way, clearly this spat wasn't his finest hour, not least by trying to erase it ever happened.Engineers generally refer to r-squared loses, not 1/r^2. What Perry said makes no sense. She said the r-squared issue doesn't matter with a tightly focussed beam, but r-squared loses apply regardless of the beam width.
Ocko didn't say "R^2 losses", he said "R^2 math" and then said it was Twitter-speak. Had he said "R^2 losses" I'd agree.
On the point of the tightly focussed beam, in the far field, I agree 1/r^2 applies, but considering the aperture size, this is still in the Fresnel near field.
This takes us back to the interesting "r^2" comment in the recent twitter spat (#913). Perry was correct in my view, to point out 1/r^2, and Matthew Ocko made quite the dick of himself trying to explain it away as Twitter-speak, a bit of a "covfefe" moment. Maybe it is Twitter-speak, but I don't see any other reference to it. Either way, clearly this spat wasn't his finest hour, not least by trying to erase it ever happened.Engineers generally refer to r-squared loses, not 1/r^2. What Perry said makes no sense. She said the r-squared issue doesn't matter with a tightly focussed beam, but r-squared loses apply regardless of the beam width.
Ocko didn't say "R^2 losses", he said "R^2 math" and then said it was Twitter-speak. Had he said "R^2 losses" I'd agree.
On the point of the tightly focussed beam, in the far field, I agree 1/r^2 applies, but considering the aperture size, this is still in the Fresnel near field.I don't think we know the frequency yet, but it has to be at least 40 or 50kHz. Let's say 50kHz. That means the wavelength is <7mm. How many wavelengths of near field do you think you will get? This is not a large emitter trying to produce a plane wavefront, where only the ends of the wavefront lead to divergence. Its an array trying to produce the tightest beam it can. It will diverge in an r^2 manner from a couple of wavelengths out.
I don't think we know the frequency yet, but it has to be at least 40 or 50kHz.
45kHz to 75kHz with an output of 145dB to 155dB (or 316 W/m2 – 3kW/m2)