March 09, 2006



It's all over, all handed in =)

We both agree, that while it's good to see the back of the report, we'd both like to carry on testing the borate glasses, and implementing some of the recommendations we've made in the report.

It's like leaving a murder mystery unfinished… we must find out the answers!

March 03, 2006

Final Report Writing

Last weekend was spent modifying the interim report to a first draft of the final report. I got feedback on my report from Dr Holland and Dr Hung yesterday, they have both provided extensive advice on improvements and corrections!

So this weekend, again, will be spent toiling over the final report. There is plenty to do but only a finite amount of time… I hope I haven't left things too late.

The main thing is to get my results down in a coherent form, write a good conclusion and make all the recommended changes. Secondarily, I need to organise the report more 'scientifically' as it's a bit of a 'story' at the moment and also I must try to change my style of writing to a more passive approach… that will be the hardest bit! =)

Enough words, time for some pretty graphs:
Boron NMR graph

Raman peak fit

Raman stack plot

NMR Cobalt graph

I would tell you about them, but as I said I don't have a results or conclusion section yet!

January 30, 2006

All we care about is the data

Today, further Spinsight processing of our multiple quantum magic angle spinning (MQMAS) spectrum for the x = 0 (pure boron oxide) glass was in order: data-shifting, phasing, fast fourier-transforming and a row-adding macro gave us a presentable MQMAS spectrum with skylines above and to the side, the image of which I will have to add to this post at a later date.

Met with Diane to talk about what we have achieved so far this term and what we have left to get done, seeing as how it's week 5 already. We need to:

  • NMR our newly-made cobalt glasses, as well as the borate crystals made by Steve Feller, plus further MQMAS experiments with our x = 40 and x = 20 (again) glasses.
  • Complete our set of simultaneous thermal analysis (STA) data by running our x = 0, 5, 10, 15 and 33.33 glasses through the machine.
  • Ask Ben to please run the Raman spectrometer with our new cobalt glasses, so again we can compare Raman and NMR spectra.
  • Correct our interim reports so that we can use them as the basis for our final reports.
  • Get to work on our final reports!

Spent the afternoon working on assigning structural units to our Raman spectra peaks, which proves tricky in one or two cases. May need to review some more literature, or go back to some we may have missed details in.

Still up in the air is the apparent problem with DMFit: it seems to warp our data in a systematic way by taking a start- and end-point for the wavenumber values and assuming all the data points inbetween are equidistant (the nature of the Raman spectrometry is that they're not equidistant). Which means, on plotting the spectra in DMFit, produces a deviation from the 'correct' data which looks like the below. The correction for peak positions is simple enough, but correcting the peak integrals (that is, area under the peaks) is tougher.

DMFit deviation
Click to enlarge

Final cobalt glasses

Furnaced and poured/splatted our final two cobalt glasses (0.1 and 0.2 molar percent cobal respectively), producing two very pale blue/purple glasses, much paler than the higher cobalt concentrations. A drop of the molten 0.2% glass escaped the splatting implement (basically a heavy metal plate used to quickly squash and cool the melt), and so formed the tiny beads you see in the picture below. They must have cooled in the air, in the fall from the crucible, since they're so spherical.

Click to Enlarge

Tom, one of the postgraduate researchers, helped us fit one of our NMR spectra (the x = 40) with one quadrupolar peak in the peak-fitting program he has been developing. A single quadrupolar peak is almost certainly an oversimplification (the literature seems to suggest at least two); if we want to take this peak-fitting method further, though, the program allows for multiple peaks.

Competing with the above for picture of the day is this photograph of Nath's hair standing in all directions thanks to his safety visor (branded 'SuperVizor') plus static electricity.

Click to Enlarge

January 24, 2006

Penultimate Cobalt glass pouring

Here's a photo of me shortly before opening the 1000°C furnace and pouring the molten glass out onto a large, cold, steel plate:

The glasses poured nicely and were even darker than last time (pictured in previous blog entry) as they had 2% and 5% Cobalt oxide in them.

Here is a cunning visible-UV spectrogram of the 1% Cobalt oxide glass we made last time:

Click to enlarge

Which explains why then look purple! The absorb strongly in the visible region, especially the yellow-green around 580nm, as well as most of the red part, but then absorption tails off below 450nm in the blue. Note that the glass is mostly transparent to infrared radiation.

January 19, 2006

Glass pouring

We successfully poured another two glasses today, this time with the correct amount of Cobalt. They look a really cool purple-blue:

Click to enlarge

And the crucibles looks very cool cooling down from the 1000°C furnace temperature, I made a litte animation:

We got a really good yield from this batch as well – so we're onto a winning formula for actually making the glass!

Cobalt Glass Making

We went in on Tuesday 17th to start the furnace and pour our glass:

Click to enlarge

Today we weighed out some more powders to make the glass. The glass made on tuesday was the incorrect composition, but today we got it right! At the moment the glass is in the furnace ramping to temperature, and we'll be able to pour that at 3:30pm. This is what the powder looks like in the crucible:

Click to enlarge

At the moment we are back sorting out the Raman data, because DMfit isn't showing the x-axis accurately so we can't say what peak is what wavenumber.

January 16, 2006

Peak fitting, stoichiometry, more glass making, some more STAs…

… is today's plan.

We're going to be making some more glasses, this time with added paramagnetic ions (by introducing a cobalt compound to the mix to give the glass 0.1, 0.2, 0.5, 1, 2 and 5 molar percent cobalt). So today's work involves some tricky stoichiometry, and hopefully some powder-weighing and even some (more) glass furnacing.

If no-one else is using 'our' STA (simultaneous thermal analysis) machine, we may be able to get the last of our STAs done, and on top of that might even find time to generate a graph of the various areas-under-peaks of the peaks fitted to our raman spectra – which will give us an idea of how the proportions of structural units (and hence structure) is changing with composition.

Such is the plan. (Below is a sample peak fit, done in a quirky little program called DMFit.)

Our raman spectra for the x = 30 glass, with peaks fitted in the DMFit program.

January 05, 2006

Long day

We started the day at 10am and with not many breaks in between we are just finishing now at 9:15pm… we've baseline subtracted all the raman data and peak fitted about 20%. Peak fitting is a nightmare!

First Day of Labs 2006

The interim report was handed in this morning with no problems. Apparently there are several people wanting to read it, including a certain visiting Prof. Feller, whom we have referenced in our report as he wrote some seminal papers on the matter.

We have booked the STA for monday hoping to find out Tg for the glasses we made last term, which will lower the uncertainty in composition. This is especially important as the glass frit was heated so rapidly it foamed up and the two crucibles in the furnace were able to mix their contents.

At the moment we are in a computer room fitting polynomial baselines to the raman data so we'll be able to peak fit them accurately. It's a testing process of trial and error. Jane is doing 0, 10, 20, 30 and i'm doing 5, 15, 25. Hopefully we'll be done in a few more hours!

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  • What amazes me is that there waves and particles in that. I hope I'm right. by anonymous on this entry
  • This furnace lining and elements have now been replaced. =/ by on this entry

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