A Christmas, String Lights, Story

I bought some LED string lights before Christmas and we had them in the office, for some random cheer. The lights were mixed colours, red green and blue. They were powered by two AA batteries, and we left them on continuously for more than a week. After a while I thought some of the lights were broken but later someone else pointed out to me that only one colour remained lit.

Only green LEDs for Christmas?

Only green LEDs for Christmas?

With only the green LEDs apparently lit, the voltage measurement on the battery was 1.153 V (1.156 V with no current flowing). A fresh battery capable of lighting all the colours of LED provides a voltage of 1.311 V with the current flowing (1.325 V with no current flowing).

LEDS lit R-G-B with full voltage.

LEDS lit R-G-B with full voltage.

Strangely green LED’s are the least efficient colour, so it’s strange they would be the last ones lit…

For change in voltage, red LEDs take the least to work, and as the colour moves up the colour spectrum toward blue, the voltage requirement increases (green is between red and blue).

Approximation of spectral colours on a display results in somewhat distorted chromaticity — Wikipedia

So does this mean these LED’s aren’t really naturally green ones, and rely on phosphor filtering? Or some other technology?

Is this a problem of perception of brightness of different colours?


Digital electronics engineer James Newman, has built a ten meter long, two meter tall processor using transistors. Running at speeds up to 8 kHz the project ran out of control with total spend of forty thousand UK pounds (£40k). Unlike a computer on a chip, the system allows visualisation of the processes and architecture of a modern computer central processing unit (CPU). James is looking to site the computer in a museum or have it tour the UK to educate the public. Currently it’s possible to visit the computer during open days in James’ lounge were the machine was built.

A physically large chunk of memory built using LEDs allows visualisation of the data stored, and can be used to play Tetris!



Take the tour:

More info on the Magaprocessor website: http://www.megaprocessor.com/.

Other homebew machines can be seen here: Home Brew Computer Ring.

Parliamentary election in Cambridge

BBC radio Cambridgeshire held a debate with five candidates who have declared they will be standing for the member of parliament for Cambridge.

Julian Huppert – Liberal Democrats
Patrick O’Flynn – UKIP
Rupert Read – Green Party
Chamali Fernando – Conservatives
Daniel Zeichner – Labour

Adventures in Physical Metallurgy of Steels

During July 2013 I attended Adventures in Physical Metallurgy of Steels hosted by the Phase Transformations and Complex Properties research group of the Department of Materials Science and Metallurgy.

The programme looked like this, videos are appearing on bhadeshia123’s channel on youtube (links). There is also a playlist available.

Introduction to Adventure. H. Bhadeshia

Architectured Steels, T. Koseki

Magneto-structural coupling. I. Abrikosov

Quench and partitioning. J. Speer

Crystallographic variant selection. S. Kundu

Secondary hardened bainite, J. R. Yang

Welding of high carbon steel, K. Fang

Isotropy and Fatigue: P. Ölund

Atoms in bainite, atomic mechanisms. F. Caballero

Pulsed steels, R. Qin

Fullerenes & buckyballs in steel: I. V. Shchetinin

Boron: Type IV cracking, F. Abe

Low-density steel, H-L. Yi

Friction stirring of steel, T. Debroy

Flash Processing, G. Cola

Reliable first principles calculations for iron: A. Paxton

Steels composites for energy applications, C. Capdevila-Montes

Microstructures without contact, C. Davis

Pop-in deformation, H. N. Han

Plausibility of fine bainite, C. García-Mateo

Reduced Activation, K. Wu

Architectured microstructures, G. Anand

Flash microstructure, S. Babu

Energetic TWIP, D. Dye

Mass production of fine bainite: A. Rose

Voids and 30000 atoms, S. Munetoh

Soft Particles, T. Tsuchiyama

Mechanochemistry, F. Miani

Simplex and Kappa steels, I. Gutierrez-Urrutia

Innoculated high-speed steel, A. Chaus

Non-cubic ferrite, D-W. Suh

Montage of events

Mr Asbo ‘Disappeared’

`Cam conservators’ have introduced their final solution to permanently resolve the Mr Asbo problem and removed him to an `undisclosed location’.


Lord Sainsbury Elected Chancelor of a University in Cambridge

Lord Sainsbury of Turville has been elected by Alumni (the Senate) of the University of Cambridge. Lord Sainsburys succeeds the Duke of Edinburgh who retired as Chancellor on 30 June 2011.

The election was the first election since 1950 and the first to use the single transferable vote system. Lord Sainsburys received 52% of the vote on the first count.

Number of valid votes cast:  5558   Quota   2779

Mr Abdul Arain 312
Mr Brian Blessed 1389
Michael Mansfield QC 964
Lord Sainsbury of Turville 2893

I’m not sure how we survived since 30th of June without a Chancellor?

LIberal Doublespeak – paying more is paying less



Liberal democrats are claiming that students who will pay more for their education in the future will be paying less.

Their argument seems to be that the longer you delay paying back a loan, and the slower you pay it back the better.

I’m a bit worried that politicians can make this argument so easily, I think this is the same way they think about borrowing on the national scale. At least on the national scale one thing they often seem to forget is that the cost of borrowing can change.

I think it is very disingenuous to claim that richer students will pay more for their loans because they will pay them back sooner. Also does this mean no one will have a choice but to borrow to pay for their education, will it be compulsory to take loans from the government, or will students be allowed to pay upfront if they have the money? Paddy Ashdown seemed to claim that no one will pay for their education (only pay it back later).

Did we enter the world of double speak?

If anyone knows where I can read the proposals for this legislation please let me know. Mr Ashdown suggested we should read, but didn’t say where.