Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Paper Centrifuge

gizmodo.com

Post reply on HN
Print view View original

61–70 of 133 posts

Re: Paper Centrifuge

#61

Post by tejtm »

JohnJamesRambo wrote: post #56

I'd be suspect about the quality of the centrifuging since it is changing directions on every spin. But I haven't read the paper so maybe they have checked that. I know that when I centrifuge something delicate, even having even a very light magnetic force brake on the centrifuge on can screw up the pellet at the bottom. Rapidly changing the g-force direction like this seems like the worst case scenario.

Wouldn't the g-force direction always be the same (away from the center) regardless of direction of spin and zero at the inflection between spin directions (normal gravity excepted)?

Re: Paper Centrifuge

#62

Post by dekhn »

chriswarbo wrote: post #21
dekhn wrote: post #16

Earlier quoted context omitted.

"nothing flying off the disk will go towards the operator". What about other people? As you say, you can enclose it in a box, but that means making a glovebox, which increases cost significantly.

> What about other people? The device only requires a single person to be present. > that means making a glovebox, which increases cost significantly. You don't need a glovebox, you just need a way to pull on one of the strings from outside the box.

"Single person to be present"- so you can afford a dedicated room to spin samples? That increases cost.

You need a glovebox so you can load your samples... although technically I guess that outboarding the strings works too.

Re: Paper Centrifuge

#63

Post by Declanomous »

DanBC wrote: post #24
bluetwo wrote: post #22

Earlier quoted context omitted.

You are comparing when things go wrong with a centrifuge to every single use of this device. How would you contain the microscopic airborne particles?

>> Samples are in a vial

In re-reading my comment, I realized it isn't clear that normal centrifuges use vials to contain the sample as well.

Regardless, having spent thousands of hours in a lab, I think the traditional lab centrifuge is probably more dangerous.

Re: Paper Centrifuge

#64

Post by DasIch »

readhn wrote: post #42

Walk into any modern hospital central lab today, look at the life saving technology thats available to us and ask yourself why we still have not figured out how to give other people access to this? paper centrifuge? come on...

You mean why haven't we achieved world peace and provided the entire world with stable electricity and sufficient capital to build labs and expensive medical equipment to fill them?

Re: Paper Centrifuge

#65

Post by JohnJamesRambo »

tejtm wrote: post #61
JohnJamesRambo wrote: post #56

I'd be suspect about the quality of the centrifuging since it is changing directions on every spin. But I haven't read the paper so maybe they have checked that. I know that when I centrifuge something delicate, even having even a very light magnetic force brake on the centrifuge on can screw up the pellet at the bottom. Rapidly changing the g-force direction like this seems like the worst case scenario.

Wouldn't the g-force direction always be the same (away from the center) regardless of direction of spin and zero at the inflection between spin directions (normal gravity excepted)?

If you have something slung on one side of the tube, it will rapidly want to go to the other side of the tube as the centrifuge switches direction on the reverse spin.

Re: Paper Centrifuge

#66

Post by csours »

nneonneo wrote: post #41

As usual, what you really want to do is read the paper: http://www.nature.com/articles/s41551-016-0009 This is a well-written and very clear paper. It covers several aspects that went unmentioned in the Gizmodo article, and highlights that although building such a device may be trivial, evaluating and studying it is not. Some highlights: the paper covers how the device was built in detail, including information on th…

If I was using this thing, I would fix one end to a solid endpoint and pull the other end so that I would not be in the line of fire if the thing exploded.

Re: Paper Centrifuge

#67

Post by okreallywtf »

Looking at this makes me want to find a way to crowdsource basic research problems like this to try and take advantage of the ingenuity of people who would otherwise never even know that this kind of problem existed.

There are probably a lot of problems like this that involve making something incredibly cheap to be used in the developing world.

I think people would do that for free if they could know the bare minimum big picture of how their contribution would be used (ie, malaria treatment, even if you have no idea how your gadget could fit in). It could be something like "Need a device that can reach X rpms and can only be made of Y and Z and must cost less than N" and then just see what people can come up with.

I'm not sure how it would work on more complex problems but for clever solutions that rely on limited resources and simplicity I would love to see what people could come up with.

Re: Paper Centrifuge

#69

Post by Xylakant »

JohnJamesRambo wrote: post #65
tejtm wrote: post #61

Earlier quoted context omitted.

Wouldn't the g-force direction always be the same (away from the center) regardless of direction of spin and zero at the inflection between spin directions (normal gravity excepted)?

If you have something slung on one side of the tube, it will rapidly want to go to the other side of the tube as the centrifuge switches direction on the reverse spin.

If the diameter of the tube is small, the effect of changing direction is neglegtible compared to the centrifugal force.

Re: Paper Centrifuge

#70

Post by tdaltonc »

okreallywtf wrote: post #67

Looking at this makes me want to find a way to crowdsource basic research problems like this to try and take advantage of the ingenuity of people who would otherwise never even know that this kind of problem existed. There are probably a lot of problems like this that involve making something incredibly cheap to be used in the developing world. I think people would do that for free if they could know the bare minimum…

I think that if you could get the problem statement as concise as "Need a device that can reach X rpms and can only be made of Y and Z and must cost less than N" then the battle is won.

Another example of this kind of innovation that comes to mind is using freezing wax as a heat source to keep neonatal babies warm.

http://extreme.stanford.edu/projects/embrace

The problem statement for that would be something like, "neonates need to be kept at a stable temp."

For this one it might be, "We need some way to separate blood solids from liquids." But maybe even that is too close to a "solution stated as a problem after the fact."

I think that challenges like this are commonly used as exercises for undergrad design students. But I love the idea of expanding it. A version of the x-prizes that require basically no capital, just imagination.

Post reply on HN