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janice6

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janice6 last won the day on June 3 2018

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About janice6

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    Senior Member
  • Birthday 05/12/1939

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  • Location
    MN

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  • Occupation
    Retired, Physics Research Engineer

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  1. I guess it's all over then, we might as well give up. Seems like I have heard this crap before.
  2. Some years ago, my son (another Engineer) came over and noticed my data library. He asked what I had that for. I explained, painfully why. He laughed and pointed out to me that all data manuals were now on the Internet. I threw them all away. I have some reference texts and technical books I kept for nostalgia reasons. I also have one Semiconductor Physics book only for a paragraph on one page, where the recognized expert in the Semiconductor field stated why there would never be a Silicon based semiconductor. I remember this "Expert" at times.
  3. Yes. All my work for my whole career required citations.
  4. Some people might have called that thing he did to get himself killed, "inhaling".
  5. I'm looking forward to "his" revelation.
  6. How pathetic have we become that a sign like this is necessary...…………………….
  7. Sounds like a pretty desperate attempt at an excuse after the fact.
  8. I can't answer your question since I haven't had any interest in the field other than for my own purposes (Not tesla oriented). I would suggest that any performance of the Tesla battery pack is simply going to be a reflection of each of the individual 18650 cells it is comprised of. Therefore, if you looked up the characteristics of an "unprotected 18650 lithium rechargeable battery" you would undoubtedly get the answer to your question. Because you connect these individual cells in a configuration that suits the electrical requirement of the car, it doesn't negate that the overall performance is a multiple reflection of the single cell.
  9. As the high peak battery load increases the capacity of the battery decreases, limiting how much energy it can deliver. Load it to less high peak currents and the battery capacity will be greatly extended. Technically correct or not, one way to think of this is that the electrolyte that is between the plates of the battery is suddenly depleted with load, but given more time, the chemicals can migrate from elsewhere to increase the chemical concentration between the plates, and provide some recovery. High peak currents also cause significant heating of the electrolyte. Here is one example of a battery decrease in energy versus the discharge rate:
  10. In your retirement as in your working life, fortune favors the bold.
  11. Yes. I wholeheartedly agree. My continuing complaint is that the energy sources we have now are simply fixes, and not the solution to the problem. I obviously have no answer for what the real energy source will be, but I do know that by simply increasing the energy density of the sources we now have, will result in more catastrophic failures than what we are used to in the past. For example, in the rare occurrence of a lead acid battery suddenly failing and blowing up under the hood, the damage is fairly limited to the acid washed body panels, and radiator, etc. due to it's relatively low energy density. If you had a similar battery failure in a battery source such as the proposed increased capacity 2170 style batteries for potential use in the Tesla, you might see the car literally explode. Again! I am not against this technology, I am just stating the obvious that is to come. At one point, the idea of eliminating the storage battery as an electrical source was/is a serious consideration, in favor of replacing it with a Capacitor, that can be charged like a battery and then discharged while performing some function such as running an electric motor. This results in eliminating the electrolytes in favor of creating an extremely small infinitely porous internal structure that replicates two plates of a capacitor in the form of a microscopic sponge. This has been done and has been implemented. The ugly fact still comes back to haunt the development because to provide a significant electrical charge requires almost an infinitely porous structure of very small volume. Now we are back at the same problem as the battery, in that the energy density of the device is so high that two forms of failure will occur occasionally. One, will be the breakdown of the dielectric at a point that will produce an avalanche failure of the whole device. The second, is that the electric field strength can become so high that it can put a physical mechanical stress on the capacitor that results in it's "explosion". So far all we have done is change the configuration of the energy sources we have, we have not created an entirely new "better" energy source. Oh well. that's the task for tomorrow!
  12. I love to teach kids something new and to try to get them excited about new stuff. Learning is the greatest enjoyment I know and I try to work it into interactions with my kids of all generations. My son has taught her how to weld and use a plasma cutter, so I talked to her about how to construct and weld up a "harp" type structure to hold all the earrings I give her. Busy stuff. As an example, this weekend one of my G'daughters is coming to visit. She is learning the Violin. Her dad is an engineer, so I'm sure he has told her all about resonant string vibrations and harmonics. I am going to tell her about how fascinating a drum head is because it doesn't function by harmonic generation, but rather by overtone generation. Overtones are non-integral multiples of the fundamental, and the method of oscillation is entirely different.
  13. According to what I read on the subject, Tesla may assemble the batteries into the form factor they require. But the manufacture of the 18650 rechargeable lithium batteries themselves, are being done by a battery manufacturer. This reference states that Panasonic makes the batteries. Another reference says that Tesla is considering a new battery design and package, however the article says: "...“We’ve totally custom-engineered that cell, working jointly with Panasonic to create…an automotive cell,..." I did not say that Tesla didn't have the liability for the damage, just that it might not be their car that caused the batteries to fail catastrophically. Now, with the new talk of "supercharging the batteries", the catastrophic failures that do occur, can also start occurring on the charge cycle, due to the high current density and heating resulting from accelerated charge rates. Understand that I'm not against this technology or it's implementation, just that high energy density in any form results is a more impressive failure when failure occurs.
  14. This is on topic, but off subject. I had an accident where my wife and I got T boned in a two year old Pathfinder. It was struck in the right front wheel, hard. They had to tear off the passenger's door and cut her out of the airbags, front and sides. The first responders insisted that my wife get checked out at the hospital. While she was being checked out, I thought I might as well call my insurance company and report the accident. Wife only had a slight concussion. I got the company person on the phone and told him the story. He asked what the damage was. (I had done many insurance rebuilds prior) I told him it was totaled. He said that the circumstances didn't sound like it could be totaled. While I was talking about this, he excused himself for a minute. He immediately said, "Well from the sensor data, it appeared that I was right and it was probably totaled. In the end, it was. My point here is that I had Bluetooth music on in the car. I didn't have any subscription service through the car systems other than satellite radio. However, the insurance company got electronic shock sensor data very soon after the accident. I found this very curious that back then the vehicle was performing data communications on it's own, with another entity that I was given no information about during the purchase process. I have been through two new cars since then, and my latest has a startup screen now, that states "some" data will be electronically passed to the manufacturer (or a third party also, I don't remember for sure) and I am asked to approve a full data transfer or a minimal one. These are the only two choices to me. I found this quite interesting.
  15. Yeah. I hate it when crap happens.
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