Onion

Images made through a microscope. All subject types.

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Chris S.
Site Admin
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Location: Ohio, USA

Re: Onion

Post by Chris S. »

Brilliant thread, Saul! =D> Your onion image is enchanting, and your Sanderson prism prototypes are very intriguing.

I'd never heard of Sanderson prisms, but the papers you reference suggest they may permit very low-cost DIC photomicrography--apparently a track you're pursuing elegantly.

Are the apparent shadows in your first onion image from the Sanderson prisms alone, or did you partially occlude the condenser?

I got a thicker (5mm) plate few days ago (Aliexpress, very long shipping)), but it is too big for this setup, have to find a nice way to cut it into the pieces.
I notice that eBay has cheap listings for polycarbonate (aka Lexan, Macrolon, Tuffak, etc.) from U.S. sources, with free, expedited shipping. (Such as here and here). The 1/4 inch thickness matches the 6.25mm that Sanderson used, and is close to the 6mm named by Schultz et al.

I'm inclined to order a piece to try myself, though I'll likely mill an aluminum fixture for it, rather than 3D print something. Not that milling is better, but it's more familiar to me. Also, if I try the approach, it will likely be with reflected, rather than transmitted DIC--and reflected DIC is likely to be much less exciting.

From a bit of reading, polycarbonate appears to be easy to cut with a saw.

Please keep us updated with your further experiments.

--Chris S.

dolmadis
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Location: UK

Re: Onion

Post by dolmadis »

Saul wrote:
Mon Mar 29, 2021 7:14 pm
rjlittlefield wrote:
Mon Mar 29, 2021 7:03 pm
Thanks for the additional info!

So, one stressed plate below the condenser, and the other above the objective?

--Rik
Yes, and two polarisers
What is the best position for polarisers in relation to the two stress plates please, Saul?

Thanks

John

Saul
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Location: Naperville, IL USA
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Re: Onion

Post by Saul »

Very interesting article from Quekett (thanks to jmp from Microbehunter), which confirms some my findings. It will answer John's (Dolmadis) question also.

Cut my acrylic plate using blade saw and designed new fixture. Appears it was wasted time and efforts - 12mm thick plate was too thick - trying to apply stress it was too much for 3D printed body.

Not too bad for the condenser's side, but slider was useless. On the bright side - I had one more thin slider, which was not tested yet, with the thin plate. Combination showed positive results, especially when top slider was pushed to the side (towards more stressed position).

Next steps - use previous model, but add additional surfaces in order to keep thin plates flat (avoid twisting under stress). And make condenser's module round - it will allow to rotate whole assembly.

Below is picture of the model with thick plates & thin slider


_DSC6133-web633x950U100-G12.jpg
Saul
μ-stuff

ha8mz
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Location: Szeged

Re: Onion

Post by ha8mz »

Hi Saul! These images are brilliant. I would like to build something similar, but I'm curious what the interference should look like because it depends on how tightened the bolts are.
Another question is, do you sell these printed parts, or may I get the stl? I'm not so good at 3D modeling.
Thank you! Máté

Saul
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Re: Onion

Post by Saul »

ha8mz wrote:
Wed Oct 05, 2022 12:09 pm
Hi Saul! These images are brilliant. I would like to build something similar, but I'm curious what the interference should look like because it depends on how tightened the bolts are.
Another question is, do you sell these printed parts, or may I get the stl? I'm not so good at 3D modeling.
Thank you! Máté
Hi Máté,
I'm going to post my latest findings and ideas of this setup (I'm using little bit different setup now).
Problem is that 3d frame is too weak for the thick prism, should be a metal. Or thinner prism (not sure regarding results). Or both ...
And top prism should be high quality.
I can find these stl's for you, but (I think) they are not worth efforts, it was just a initial idea ...
Saul
μ-stuff

ha8mz
Posts: 10
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Location: Szeged

Re: Onion

Post by ha8mz »

Saul wrote:
Wed Oct 05, 2022 9:01 pm
ha8mz wrote:
Wed Oct 05, 2022 12:09 pm
Hi Saul! These images are brilliant. I would like to build something similar, but I'm curious what the interference should look like because it depends on how tightened the bolts are.
Another question is, do you sell these printed parts, or may I get the stl? I'm not so good at 3D modeling.
Thank you! Máté
Hi Máté,
I'm going to post my latest findings and ideas of this setup (I'm using little bit different setup now).
Problem is that 3d frame is too weak for the thick prism, should be a metal. Or thinner prism (not sure regarding results). Or both ...
And top prism should be high quality.
I can find these stl's for you, but (I think) they are not worth efforts, it was just a initial idea ...
Thank you for your answer! I found out that some safety glasses have 2mm polycarbonate, so I try to make something with these, but also I ordered 6mm thick sheet from aliexpress. I think that metal would be better, but it's harder to work with at home without equipment. But I would be happy with your previous results too. Could you make an image about the interference pattern with your prism? Thank you!

ha8mz
Posts: 10
Joined: Wed Oct 05, 2022 11:52 am
Location: Szeged

Re: Onion

Post by ha8mz »

ha8mz wrote:
Wed Oct 05, 2022 10:29 pm
Thank you for your answer! I found out that some safety glasses have 2mm polycarbonate, so I try to make something with these, but also I ordered 6mm thick sheet from aliexpress. I think that metal would be better, but it's harder to work with at home without equipment. But I would be happy with your previous results too. Could you make an image about the interference pattern with your prism? Thank you!
This is what I see now with my thin 2mm polycarbonate.
Attachments
310541076_1150043912608451_7662900777224618694_n.jpg

ha8mz
Posts: 10
Joined: Wed Oct 05, 2022 11:52 am
Location: Szeged

Re: Onion

Post by ha8mz »

Saul wrote:
Wed Oct 05, 2022 9:01 pm
ha8mz wrote:
Wed Oct 05, 2022 12:09 pm
Hi Saul! These images are brilliant. I would like to build something similar, but I'm curious what the interference should look like because it depends on how tightened the bolts are.
Another question is, do you sell these printed parts, or may I get the stl? I'm not so good at 3D modeling.
Thank you! Máté
Hi Máté,
I'm going to post my latest findings and ideas of this setup (I'm using little bit different setup now).
Problem is that 3d frame is too weak for the thick prism, should be a metal. Or thinner prism (not sure regarding results). Or both ...
And top prism should be high quality.
I can find these stl's for you, but (I think) they are not worth efforts, it was just a initial idea ...
Hi Saul!
I've got 2mm polycarbonate, and it's much easier to bend. I have this kind of pattern, but I'm a bit clueless about the upper prism because my microscope doesn't have an objective filter holder. Could you find the STL files? They could help me a lot. Thank you!
345041747_1442701633137396_8135763568260100610_n.jpg

hkv
Posts: 535
Joined: Wed Jan 02, 2013 3:58 pm
Location: Sweden

Re: Onion

Post by hkv »

Great and beautiful capture and interesting setup!
https://www.instagram.com/micromundusphotography
https://www.flickr.com/photos/micromundus
https://www.youtube.com/channel/UC0UdYN ... YH_litDZjA
Olympus BX51 | Olympus CX23 | Olympus SZ4045 | Carl Zeiss Jena Sedival | Swift FM-31 | Zeiss EVO LS 10

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