6 ms·

I could come up with electrical motors and generators. Before that I saw them for controlling the arm of spinning hard drives, and those aren't used that much a

by VMG 9y ago

I could come up with electrical motors and generators. Before that I saw them for controlling the arm of spinning hard drives, and those aren't used that much anymore. What else is there?

falsedan 9y ago
> spinning hard drives, and those aren't used that much anymore Hey! Are you basing this statement on your own experience of your personal/business hardware? Because spinning rust has never been more heavily used, for bulk on/near-line storage. Judging by the list of alumni from Prof. Wang's group, HDD manufacturers have a strong demand for advanced applications of magnets, plus a tiny fraction from biomedical techs. [0]: http://www.nanospin.umn.edu/people-0 http://www.nanospin.umn.edu/people-0
- VMG 9y ago
  You were right, I did not consider bulk storage outside my personal use. Thanks.
- theandrewbailey 9y ago
  Hard drives are one of those big technologies that are more widely used and more important after they are obsolete[0]. [0] for some definition of obsolete.
lloydjatkinson 9y ago
> spinning hard drives, and those aren't used that much anymore. Not sure if serious or not. Just because SSD's are popular, does not mean HDD's are unused.
CamperBob2 9y ago
Low-field MRI could probably benefit from a 2x improvement in the state of the art.
- lostlogin 9y ago
  High temperature superconductors are what MRI needs.
  - CamperBob2 9y ago
    "MRI" covers a very wide variety of imaging and analysis techniques under the general category NMR (Nuclear Magnetic Resonance). Some forms of NMR analysis actually use the Earth's magnetic field (https://en.wikipedia.org/wiki/Earth%27s_field_NMR https://en.wikipedia.org/wiki/Earth%27s_field_NMR). Basically, the stronger the fixed magnetic field, the more you can see and do.
    - lostlogin 9y ago
      Exactly. Super conductors are the ones I use and high temperature superconduction will likely make maintaining a super conductor much cheaper (after you spent lots on a whole new system).
comboy 9y ago
Why is this being downvoted? Prev post said you don't realize how many magnets are around you, so the parent is asking. I wanna know too. I additionally came up with speakers/headphones, connectors, reed switches.
pingec 9y ago
Here are some more items I can think of: speakers, earphones, magnetic switches (eg. laptops), relays, sensors, CD/DVD ROM, maglev.
- beaconstudios 9y ago
  AFAIK they all use electromagnets rather than permanent magnets.
  - AlexandrB 9y ago
    Last time I checked speakers and headphones still had a single permanent magnet + an electromagnet. However, for speakers, the "old" iron permanent magnets generally work just fine - they just have to be bigger.
    - dahauns 9y ago
      "Just have to be bigger"? I want lighter guitar amps that don't cost an arm and a leg, dammit! :)
      - bsder 9y ago
        Then go solid-state. Inverter-based power supplies are sufficiently light that a guitar amp should only be the weight of the wood and the speakers. And, the speakers have to be a certain size to move the correct amount of air--so the copper coil is probably the limiting weight. It's remarkable how much air you have to actually move to get decent sound volume.
        dahauns 9y ago
        Hm...sounds plausible from a physics POV, but maybe there's something else? Since, in practice (at least as far as I can speak from experience), old-school ferrit 15" speakers are ~7-8kgs, while you can get similarly specced neodymium speakers that weigh about half (3-4kgs).
wycx 9y ago
Wigglers and undulators.
Sean1708 9y ago
> and those aren't used that much anymore There's still a lot of active research going into magnetic tape storage, I find it very difficult to believe research into hard drive storage is going to slow any time soon.
mfrykman 9y ago
Most commercial drones have 4 motors w about 12 magnets each. Some others: electric bikes, electric skateboards, power tools, blow dryers, iPad cases. If I recall correctly, one of the earlier iPhones was basically held together w rare earth magnets, with the screen module magnetically stuck into the case. Can't find info to verify this though, so take it w a grain of salt.
- saagarjha 9y ago
  Wasn't this the iMac?

by VMG 9y ago

I could come up with electrical motors and generators. Before that I saw them for controlling the arm of spinning hard drives, and those aren't used that much anymore. What else is there?

falsedan 9y ago

> spinning hard drives, and those aren't used that much anymore Hey! Are you basing this statement on your own experience of your personal/business hardware? Because spinning rust has never been more heavily used, for bulk on/near-line storage. Judging by the list of alumni from Prof. Wang's group, HDD manufacturers have a strong demand for advanced applications of magnets, plus a tiny fraction from biomedical techs. [0]: http://www.nanospin.umn.edu/people-0 http://www.nanospin.umn.edu/people-0

VMG 9y ago
You were right, I did not consider bulk storage outside my personal use. Thanks.
theandrewbailey 9y ago
Hard drives are one of those big technologies that are more widely used and more important after they are obsolete[0]. [0] for some definition of obsolete.

lloydjatkinson 9y ago

> spinning hard drives, and those aren't used that much anymore. Not sure if serious or not. Just because SSD's are popular, does not mean HDD's are unused.

CamperBob2 9y ago

Low-field MRI could probably benefit from a 2x improvement in the state of the art.

lostlogin 9y ago
High temperature superconductors are what MRI needs.
- CamperBob2 9y ago
  "MRI" covers a very wide variety of imaging and analysis techniques under the general category NMR (Nuclear Magnetic Resonance). Some forms of NMR analysis actually use the Earth's magnetic field (https://en.wikipedia.org/wiki/Earth%27s_field_NMR https://en.wikipedia.org/wiki/Earth%27s_field_NMR). Basically, the stronger the fixed magnetic field, the more you can see and do.
  - lostlogin 9y ago
    Exactly. Super conductors are the ones I use and high temperature superconduction will likely make maintaining a super conductor much cheaper (after you spent lots on a whole new system).

comboy 9y ago

Why is this being downvoted? Prev post said you don't realize how many magnets are around you, so the parent is asking. I wanna know too. I additionally came up with speakers/headphones, connectors, reed switches.

pingec 9y ago

Here are some more items I can think of: speakers, earphones, magnetic switches (eg. laptops), relays, sensors, CD/DVD ROM, maglev.

beaconstudios 9y ago
AFAIK they all use electromagnets rather than permanent magnets.
- AlexandrB 9y ago
  Last time I checked speakers and headphones still had a single permanent magnet + an electromagnet. However, for speakers, the "old" iron permanent magnets generally work just fine - they just have to be bigger.
  - dahauns 9y ago
    "Just have to be bigger"? I want lighter guitar amps that don't cost an arm and a leg, dammit! :)
    - bsder 9y ago
      Then go solid-state. Inverter-based power supplies are sufficiently light that a guitar amp should only be the weight of the wood and the speakers. And, the speakers have to be a certain size to move the correct amount of air--so the copper coil is probably the limiting weight. It's remarkable how much air you have to actually move to get decent sound volume.
      - dahauns 9y ago
        Hm...sounds plausible from a physics POV, but maybe there's something else? Since, in practice (at least as far as I can speak from experience), old-school ferrit 15" speakers are ~7-8kgs, while you can get similarly specced neodymium speakers that weigh about half (3-4kgs).

wycx 9y ago

Wigglers and undulators.

Sean1708 9y ago

> and those aren't used that much anymore There's still a lot of active research going into magnetic tape storage, I find it very difficult to believe research into hard drive storage is going to slow any time soon.

mfrykman 9y ago

Most commercial drones have 4 motors w about 12 magnets each. Some others: electric bikes, electric skateboards, power tools, blow dryers, iPad cases. If I recall correctly, one of the earlier iPhones was basically held together w rare earth magnets, with the screen module magnetically stuck into the case. Can't find info to verify this though, so take it w a grain of salt.

saagarjha 9y ago
Wasn't this the iMac?