I think this was primarily about speeding up the measurement time.
With just two electrodes you had to wait for the device to achieve equilibrium with the material being measured. If the concentration of oxygen on the probe side of the barrier was higher or lower than the material side you would get false measurements, particularly in low oxygen scenarios because you have oxygem trapped in the probe.
By keeping the state of oxygen inside the probe constant and replacing consumed molecules you now can measure almost instantly.
Yes but how do you do that? that magical third electrode sounds harder to make than the original problem.
Edit: I think I get it now, it's a chemical reaction. By applying a voltage with some polarity to the 3rd electrode you can run the reaction in reverse. Still very hard to achieve because you have to make sure the reactions happen at the same rate with the same efficiency, which is far from trivial. This must be a very high end sensor for all this effort to make sense.
An oxygen molecule does some chemical reaction on the sensor electrode that releases an electron, maybe it's made of iron and turns into rust. If you supply the same current to another electrode to do the opposite reaction, maybe one made of rust that turns into iron, it balances.
The sensors must be consumable with a certain lifetime.
Zinc can do this too. But I like silver, its oxide has decent conductivity.
One of the common arrangements on a basic two-electrode sensor is to have one gold electrode to make contact with the electrolyte, and the electrolyte provides conductivity to a sacrificial silver electrode. With electrolyte exposed to the atmosphere through an oxygen-permeable membrane.
As oxygen makes its way through the membrane, it is consumed by the silver at a steady rate and equilibrium is achieved relative to how much oxygen is in the atmosphere. This generates a steady current which is amplified to move a needle on a gauge, where there are knobs to adjust the meter until it displays the correct amount of oxygen during calibration against a known concentration. And must also be calibrated to display zero when there is no oxygen.
Eventually even if the membrane never gets fouled the oxidized silver builds up in the electrolyte chamber and response deteriorates so maintenance is needed. Remove the membrane, polish the silver, put in fresh electrolyte, new membrane, and re-calibrate.
Adding a third electrode opens up a number of further possibilities.
One of them is the option to use an additional inert gold or platinum contact or a salt bridge as electrical reference against the original gold or silver as the sensor. Plus using a more complex circuit than a plain amplifier, apply controlled responsive current to the sacrificial silver at the same time. So rather than directly amplifying the current produced by different concentrations of oxygen existing in the electrolyte (and waiting for it to equilibrate), instead with 3 (or 4) electrodes the ionic silver concentration in the electrolyte can be maintained electronically in a steady state, and as oxygen permeates, the current required to replace the consumed silver is designed to make a dfferent kind of meter move the needle the same way as above. In this way the oxygen concentration in the electrolyte varies to a much more limited extent compared to waiting for it to be depleted from a high amount to zero before the meter will bottom out.
This can be equivalent to constant-ion electrochemical titration.
Disclaimer: I always like to handle things like this like lives depended on it, because lives depended on it.
> Disclaimer: I always like to handle things like this like lives depended on it, because lives depended on it.
You do the best you can. If you can only make inaccurate sensors, make inaccurate sensors. If you can make accurate sensors, make accurate sensors. If they're much more expensive, make both. If your competitor has more accurate sensors, learn how they work.
You definitely don't have to be god tier anything, you just need to know at least a little more than the companies you are consulting for.
This kind of work has been my primary income for the last 4 years or so. Nowhere near on the same level as Feynman, but I know enough about enough other things that I get a lot of reputational referrals.
>you just need to know at least a little more than the companies you are consulting for.
sometimes (i'd argue often, actually), you don't even need that. simply having an outside/fresh perspective and the fact that you aren't part of any of the existing groups/silos is valuable.
Often the most useful thing is just listening to the right people in the company. I wouldn't be 100% surprised if someone in the company in the story had already had the idea for the third electrode, but it took the suggestion from the high-paid consultant to get it taken seriously.
Factory overhiring can happen easily by adding speculative 2nd and 3rd shifts. No need for extra equipment, tooling, or physical capacity.
Lines with specialty equipment and tooling can also often be sped up. That can allow for other jobs to be added to all the functions that support the processes involved before and after the specialty equipment.
New employees also often require training and some apprenticeship time, meaning they can get hired ahead of actual demand.
The 90th percentile of factory workers makes $45,000. The 90th percentile of software engineers makes $230,000. Hiring in tech is insanely expensive; I'm not familiar with hiring in factories, but it can't possibly have the supply problems that tech workers have. I do on average 115 interviews for every person I hire in tech.
There exists greater issues in hiring for manufacturing when it is for new shifts. Master level technicians and foremen willing to work those hours can be exceptionally difficult to find, and everything flows out of these people. While similar issues likely exist relating to discovering talent for software development, I speculate that the factory will, in practice, have a harder time finding people (for new shifts).
My experience with seeing new shifts added is initially with only specific processes, and even with those it is with journeyman level technicians running a small crew to support relieving a bottleneck in production.
Alternatively, manufacturers can outsource until they have enough volume to add a shift, but across the economy the net is just transferring production from one facility to another.
While I am in the camp that believes camera-only FSD won't succeed, your comment isn't entirely accurate.
CCD and CMOS sensors can easily work in sub-freezing temperatures with various kinds of heating. There are 10's of millions of surveillance cameras installed outdoors in sub-freezing climates that work fine.
Cameras also have moveable IR cut filters, which is analogous to your sunglasses example.
Human eyes do have greater dynamic range in the visible light spectrum, but solid state sensors can commonly interpret light above 1000nm, and of course you can do thermal/IR imagers to provide optical sensing of wavelengths outside of what a human can see.
Sensor technology relative to the human eye isn't what is holding FSD back.
It's been "coming this year" for almost a decade now.
The bugs you describe are not embarrassing, they are critical issues that prevent it from being called FSD.
This is the first year that I personally think that it will come this year...
Actions speak louder than words, and the fact that a 'cybercab' production line is firing up this year is also a strong indicator - the fact they didn't do that 5 years ago means tesla leadership didn't think it was going to work back then. 'cybercab' wouldn't sell well as a 2 seater if it couldn't self drive. (although the actual mass production will be delayed till next year is my guess, but we'll see model 3 or y being used for a taxi service in the meantime)
It will be interesting to see.
At this point, I think much of what is coming out of Tesla in both words and actions is stock price theater.
They "fired up" a Cybertruck production line and we all see how that went.
It failed based on the sales projections that Tesla set. Also, several reviews have not exactly been kind, along with lots of comments from owners about annoying issues and malfunctions.
If Tesla needed beta testers for things they hadn't figured out yet there would have been better ways to go about that.
Not an expert, but a more-than-casual-observer as someone who has lived on the water (literally and figuratively).
A core part of the problem is things like the farming in California that uses excessive amounts of water, which is already brought in from very distant regions.
I don't think there is a way to distribute the fresh water supply equitably if you have various regions and industries that insist on being highly inefficient and wasteful. California is certainly not the only example, there are lots of places trying to grow crops in illogical places, water supplies being polluted by industries, etc.
The problem isn’t just farming in the desert. The problem is all those people living in the desert in the first place. There is a reason the Spanish then the Mexicans did almost nothing to settle and develop California. It was massive water projects by the U.S. Army Corps of Engineers that made modern California possible.
It's really intertwined. While California exports a LOT, people need to eat and the economies of scale lean towards eating locally grown crops. Living in a desert creates some degree of demand for local crops.
1. crops in the desert are generally OK if they are directly for human consumption. The problem is growing alfalfa and other crops intended to feed livestock - they are incredibly thirsty crops, and the end result is not a lot of food in terms of nutrients or calories. Plus the little detail that a huge amount of the meat produced in the SW is exported to Asia, and so it might "look local" but actually isn't
2. even human-consumption crops are a lesser problem if the farms use the old techniques collectively known as "flood irrigation". Farming in the SW needs to switch to drip irrigation, which requires a significant capital investment by farmers, and I don't think they should be required to bear the whole (and perhaps not even the majority) of that cost.
California isn't even the problem. They're rich enough and big enough, (and fortuitously situated enough), that they just crank up desal plants and go happily on their way.
What about the rest of the west?
Arizona? New Mexico? Nevada? etc etc
Water needs to be brought in from somewhere? Who's going to pay for that? How do you do it safely, sustainably. And on and on.
I know people forget the rest of the west a lot. (Or maybe they just don't care about us as much?) But it's actually more of an issue in those places than it is in California.
A personal illustrative story. I used to live in Scottsdale. The water issue is such common knowledge out there that people started trying to get into the magic zip code. (Phoenix sits on like a gazillion years worth of water that they squirreled away.) I had moved into the magic zip code just about 1 year before everything went crazy. As it happened, about 18 months after we moved to that zip, we decided to move back to the Great Lakes region. Fully expecting to lose money on the house. But the word had got out on that zip code, and the final offer was over 60% more than we'd paid just 18 months prior.
That gives an indication of how even individuals are thinking. It just kind of felt like a lot of people, governments and organizations know there will be an issue, but money is gating everyone's ability to do anything about it.
Whereas of course, money's not as much of an issue in California.
I think large parts of the west will need help in the future. Or people will need to pay significantly more in taxes to live in those places.
It can't go on forever the way it has been. That much is certain.
>Phoenix sits on like a gazillion years worth of water that they squirreled away
True, but most of the groundwater under phoenix was contaminated by three superfund projects . Article [0] is from 2019 and says it’s “delayed”. They hit some targets in 2024, supposedly working on it with review due sometime this year [1]
Some of the suburbs haven’t been reached by the groundwater plumes, but phoenix itself was 2/3 in scope. So you don’t have a supply issue in maricopa city (which is a whole separate water district.. and an expensive one too: $100 bill even if you don’t use a drop), city of Scottsdale, etc
They're not segregated by zip, they're segregated by city.
If you live in Scottsdale, not in a certain zip, and the ish hits the fan water-wise, Phoenix is not giving you water. It's up to Scottsdale to provide you services.
That's why they call it a "magic zip". Not because of the zip itself, but because you get Phoenix services in that zip.
It's actually really important to know things like that when buying property down there. Some places have aquifers and reserves and others don't. Who is providing your services can have a critical impact on not only your quality of life, but also your property value.
Also, higher taxes is what it takes to create the new infrastructure to bring in water.
You gonna do a deal with California to get in on their desal plants? The infrastructure to pull that off will cost money. You gonna go the other way and desal through Texas? Even more money. Gonna continue to trust the Colorado and upgrade that infrastructure? Probably cheapest, but still a lot of money.
Essentially, whatever solution you come up with, it will cost money. Either the feds will have to pay it, or, as I said, the people who live in those areas will have to acclimate themselves to paying significantly higher taxes.
What you're describing is an artifact of the current political structure of the Phoenix area. When the shit hits the fan (which it might, and it might not) that political structure is going to be amended.
I don't think that moving water from CA is a part of the future for Arizona. If it was, then sure, taxes will play a role in that.
Even the solution I prefer - massively reducing agricultural water usage - will require money, but money is not going to create water near Phoenix IMO.
Everything I've read about desalination is that it is not really economically feasible. Has that changed? I don't think CA can "just crank up desal plants" in a practical sense.
But when I was in Scottsdale, I still considered it a long shot. The hot idea down there at that time was that giant Arizona desert PV farms would feed California electricity. They would send it back in the form of water.
Definitely works on paper. Only gets cheaper to operate the solar farms over time. But enormous capital costs.
Who's paying all that? I don't really think most of the people down in Arizona have the money it would take for that up front charge.
That's what I meant. California can float those kinds of costs. So for a place like California, it's definitely something they can do if the issue is pressed on them.
Places like Arizona, New Mexico, Nevada, I don't think they can? Maybe? But I don't think so. That's why I believe if the issue is pressed in western states outside of California, you would see much higher taxes that would likely make some people have to move.
> California can float those kinds of costs. So for a place like California, it's definitely something they can do if the issue is pressed on them.
That's correct. For reference, the simple upfront build cost of the desalination plant in Carlsbad in 2015 worked out to approximately $300 per county resident, which was peanuts to become effectively impervious to drought conditions in a populated and economically prosperous desert. San Diego had an over-$200B economy at the time, over $300B now.
How much has the infrastructure improved since then? I see on TV that some of California has snow and flash flooding. Are there attempts being made to capture that, or soak it into the ground? Or is it cheaper to keep using the old projects?
I see on YouTube that there are parts of Texas you can buy for peanuts because ranching doesn't work there any more. I gather that the cows eat so much of the ancient grassland away that the soil washed away and now we have flash flooding? Then I see terrible flooding in the main rivers. I wonder if it is because governments are (or were) good at big centralised water projects, but spending for thousands upon thousands of swales and check dams to be built is harder, and less sexy?
"Artists" are currently trying to create false scarcity, not totally unlike the DeBeers/diamonds false scarcity.
Historically, Artists have often had (mostly) uncredited assistants that handled a lot of the grunt work. This is particularly common, IME, for physical media artists that do large sculptures and similar pieces. "The Artist" will do the initial design, and then "artists" working under their direction will do a lot of cutting and welding, for example.
AI is upending a lot of this because it is letting more people become Artists in the sense of bringing a vision into reality via the use of various external helpers.
In the end all visual artists are just manipulating how photons hit our eyes, and there are lots of ways to make that happen pleasantly.
> Historically, Artists have often had (mostly) uncredited assistants that handled a lot of the grunt work. This is particularly common, IME, for physical media artists that do large sculptures and similar pieces. "The Artist" will do the initial design, and then "artists" working under their direction will do a lot of cutting and welding, for example.
I'd say the right thing to do in such cases would be to credit the whole team, like movies do when the credits roll, rather than conclude that the term "artist" is meaningless anyway because some people take credit for the work of others.
When you say "Art" can only come from a person who drew a line directly with their own hand, vs. a person who told a computer to draw a line, it's false scarcity. Both lines could wind up looking identical, but the Artist is trying to make the world believe only one of those lines is truly valuable.
I'd be interested to see you expand your comment beyond what you wrote. I don't have a horse in this race, I'm a terrible Artist and have no interest in using my time to create visual baubles with AI. I just see it as an interesting thing that is playing out.
Not just deferred message propagation, but also a way to setup medium to high powered rebroadcasting stations. For political unrest scenarios, you don't always need 2-way communication, but you do need to distribute critical info. A listen-only mode makes it very difficult to track individual users (no RF transmissions), and would cover a large percentage of a critical use case.
All of this is solved with the store-and-forward model that you highlight.
A Lora dongle seems to be better than BT, though potentially incriminating.
By keeping the state of oxygen inside the probe constant and replacing consumed molecules you now can measure almost instantly.
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