Perfect Anniversaries

The young author of  The Math Less Travelled has just celebrated his 28 birthday, noting that 28 is a perfect number.  He laments that since the next perfect number is 496, it is most unlikely that he will see another perfect birthday, but he should not lament.

With the aid Anniversaries.zip, and the knowledge that the 5th perfect number is 33,550,336, we can see that on Wednesday, 25 October 2045 someone born on 10th January 1982 will be a perfect number of minutes old.

As for me, I will reach my 33,550,336th birth minute on Sunday, 18 January 2015. I can hardly wait.

Aniversaries.xls

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Anathem (review of a book I haven’t read)

This thread at the Self Service Science Forum

http://www2b.abc.net.au/science/k2/stn/newposts/4494/topic4494948.shtm

said:

“I’ve been reading a bit of Neal Stephenson Sci/Fantasy recently. His bag is to combine philosophy of science concepts with historical/sci fi themes to produce interesing fiction. Think Iain M Banks with more nerdy accuracy.

Often the concepts get introduced using different names, like they are universal ideas that are rediscovered. In the book i’m reading at the moment, Occam’s Razor becomes The Steelyard. There is a concept called Diax’s Rake, which basically states:

Watch out for ideas you like the sound of…

It’s a very sensible idea, but not something I came across during the half of my degree doing Hist and Phil Sci subjects (apart from the usual objective/subjective stuff).

Does anyone know the historical reference for this?”

This led me to ask if the concept of “confirmation bias” was relatively recent, to which someone pointed out:

“I was just reading http://en.wikipedia.org/wiki/Confirmation_bias

It quotes Francis Bacon:

The human understanding when it has once adopted an opinion (…) draws all things else to support and agree with it. And though there be a greater number and weight of instances to be found on the other side, yet these it either neglects or despises, or else by some distinction sets aside or rejects[.]

So the idea of it is about as old as modern science.”

and a little more search found:

http://anathem.wikia.com/wiki/Diax’s_Rake

“Never believe a thing simply because you want it to be true”

A warning against wishful thinking attributed to Diax.

Suspected Reference

This appears to be a reference to Thucydides, who said, “…[I]t is a habit of mankind to entrust to careless hope what they long for, and to use sovereign reason to thrust aside what they do not desire”

So it seems that the concept of confirmation bias is not only as old as modern science, it’s as old as ancient science as well.

You have to love the Internet

Oh, I nearly forgot the review:

http://eslewhere.adactio.com/journal/1542/

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Frame4.xls – Update2

It was recently pointed out to me that the Frame4 spreadsheet was giving an overflow error with a fairly small analysis.  The problem turned out to be that the analysis did not have any restraint specified in the X direction, resulting in a division by zero.

I have now added a check of restraints to ensure that there is at least one node restrained in each of the X and Y directions.

The modified spreadsheet can be downloaded from Frame4.zip

Link to the original Frame4 post: Frame Analysis with Excel – 7; Shear deflections and support displacements

Posted in Excel, Finite Element Analysis, Frame Analysis, Newton, VBA | Tagged , , , | 12 Comments

Distributing Silverfrost Fortran Applications

Earlier posts have included User Defined Functions (UDFs) linked to Fortran dll files compiled with Silverfrost Personal Fortran:

Solving simultaneous equations – Fortran dll

Trigonometric Functions – dll

Linking Excel to Fortran – 2

Transferring these files to a new computer it came to my notice that if the Silverfrost compiler is not installed it is necessary to install the file SALFLIBC.DLL in the same directory as the dll files (usually Windows/System32).

See this Silverfrost Forum post for more details.

The required file can now be downloaded from: Salflibc.zip 

Alternatively install the Silverfrost Personal Fortran Compiler (free for personal and evaluation use).

Anyone still having problems with the Fortran UDF files after installing the Salflibc.dll file, or the entire compiler, please leave a message.

Posted in Excel, Link to dll, UDFs, VBA | Tagged , , , , , | 2 Comments

Just in Time for Christmas!

The new version of the Australian Standard Concrete Structures Code (AS 3600) has just made it for 2009:

Download from SAI Global

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