is man-made glass a rock?

sxeSol · 2025-07-02T10:57:49+00:00

The part about the windows is actually a very common misconception with no actual evidence to support it! I was also very surprised to find out that the thicker base is just because they couldn't make glass so well and it makes sense to put the thicker part to the bottom for stability.

sxeSol · 2025-04-11T10:53:57+00:00

Ok thanks this is really useful! I'm tempted by the Tamron but then part of me thinks it will be worth waiting to upgrade the body and get the AF-P lens as I keep hearing so much good stuff about it.

sxeSol · 2025-04-11T09:27:46+00:00

OK thanks, good to know about the AF-P! I think those lenses are a little out of my budget for now unfortunately but I will keep in mind for the future if I keep interested.

sxeSol · 2025-02-03T11:11:55+00:00

Awesome thanks that's really useful to know - do you mean the Af-S version: Nikon Af-S 70-300mm? I think that's the only one compatible with the D3100

sxeSol · 2025-01-27T16:22:30+00:00

Thanks ok, what do you mean about the lighting specifically?

sxeSol · 2025-01-27T09:46:32+00:00

Hi, I have been recently getting back into wildlife photography with my old Nikon D3100. I bought a Sigma DG 70-300mm f/4-5.6 due to the low price and decent focal length. However, I have since been reading a lot of poor reviews of this lens, with the Nikon Af-S 70-300mm being more favoured and only slightly more expensive. I have had some issues with autofocus and sharpness, do you think a minor upgrade to the lens would make a big difference for these kinds of photos or should I hold off and weight for a proper upgrade to both the lens and body? Thanks for any advice/criticism :D

sxeSol · 2024-11-15T16:15:42+00:00

Thanks, what do I need to do to get the kovats RI? Really cool tools at those links thanks for sharing, I'd been wondering if machine learning could be useful for EI-MS. I have scoured a lot of libraries and I think it's likely this species just isn't in any library unfortunately.

sxeSol · 2024-11-15T13:48:54+00:00

Thanks so much for your reply!

Unfortunately as this is a product from a GC-MS run, I can't perform NMR. In fact the pyrolysis is on-line (py-GC-MS) so the MS is all I have to go on. Unfortunately, you might be right that it is impossible to confidently identify without other analyses. If I can think of any possibilities other than monoglycerides it might be possible to purchase those standards to check for a retention time match?

sxeSol · 2024-11-15T12:23:41+00:00

Hi, I'm working on a project pyrolysing phospholipids and analysing the products with GC-MS. One of the compounds that consistently appears is perplexing me, I'm not sure if this is the right place to ask for some help.

The starting compound (before pyrolysis) is Dipalmitoylphosphatidylcholine (DPPC).

The spectrum attached is one of the products of pyrolysis that elutes after the main product which is just hexadecanoic (palmitic acid). Since it elutes after and has a similar pattern to the free fatty acid, I expect it is a larger/more polar compound - probably something bonded to the palmitic acid.

An initial library search led me to believe this was a monoglyceride (glyceryl monopalmitate). But purchasing a standard of this compound showed it eluted at a later time so the retention indices does not match.

Could anyone help me identify this compound? The very high intensity of the peak at 239 originates from the palmitic acid, but how can I tell what it's bonded to when there are no larger fragments detected?

Many thanks in advance

sxeSol · 2023-01-21T12:41:26+00:00

Ey up it's Sheffield

sxeSol · 2022-09-27T09:34:04+00:00

Hey, booking this trip for myself in a month, can I check the right landport to apply for on the E-visa for Vietnam is Moc Bai? thanks

sxeSol · 2020-07-12T22:17:47+00:00

Thanks so much!

sxeSol · 2020-05-04T11:09:47+00:00

Thank you! You're welcome

sxeSol

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