An ode to DynoChem ODEs

You may be familiar with Shakespeare's Sonnet 116, which begins "Let me not to marriage of true minds admit impediments".  While thinking about what stops chemists and engineers from writing fundamental models of their processes, Shakespeare's original has recently been adapted as follows:

Let me not to mod'ling alongside tests

Admit impediments. Mod'ling is not

Fit that needs hand coding in Excel sheets

Or MatLab when it alteration needs

Or systems with high barriers to use

For purpose fits the DynoChem approach

Looks on reality and is not shook

It is the start to every system stiff

Parameters unknown till data tak'n

DC's not time's fool. Phases, heat effects

And concentration in its compass come

It grows with brief hours and weeks in updates

At scale-up.com with new process schemes

If using other tools you feel you're hosed

Try DynoChem instead with points impos'd.

The original goes like this:
 

Great Bards of QbD: Dr Seuss?

There are not many poets associated with QbD, so this next one is a bit of a stretch to include in the series.  The technical QbD contribution comes from Dr Art Etchells, the outstanding fluid mixing consultant who had a long and distinguished career at DuPont and now teaches and consults more widely.  For an example of Art's work, see his chapter on pipeline mixing in the Handbook of Industrial Mixing.  Anyone designing flow chemistry systems will find this material useful and we are building related tools for our users.

The rhymes and philosophical contribution are from Dr Seuss, to whom I was introduced by Art [tenuous connection - Ed] while walking in downtown Philadelphia about 10 years ago.  I was looking for books for my daughter and being European had not heard much about Dr Seuss.  After Art's introduction, we never looked back and my daughter went on to read early and well.  I was struck by the quality of the writing and still pick up the books today, while she has outgrown them.

One in particular seems to encapsulate much of the QbD journey: I Had Trouble in Getting to Solla Sollew (aka The Desired State).  You can buy the book at Amazon, for example - I recommend it for any age.

The pre-QbD era is remembered with nostalgia early on:

I was once happy and carefree and young

And I lived in a place called the valley of Vung

And nothing, not anything ever went wrong...

Until one day, a defect / deviation / excursion from a poorly understood process occurs:

Sock! What a shock!

I stubbed my big toe

On a very hard rock

And I flew through the air

And I went for a sail

And I sprained the main bone

In the tip of my tail!

A better way to work is needed, and our hero devises a plan:

If I watch out for rocks

With my eyes straight ahead

I'll keep out of trouble

Forever, I said.

This univariate approach does not work:

And I learned there are troubles

Of more than one kind

Some come from ahead

And some come from behind.

In an apparent reference to a proven acceptable range (PAR):

I'll watch out for trouble in front and back sections

By aiming my eyeballs in different directions.

There were some difficulties with the PAT instrumentation:

I found this to be

Quite a difficult stunt

But now I was safe

Both behind and in front.

And the multivariate nature of problems makes things more difficult:

Then new troubles came ...

From above!

And below!

And now I was really in trouble, you know.

An adviser of sorts comes to his aid (in a 'One Wheeler Wubble'; e.g. via a LinkedIn group), promising:

I'm off to the city of Solla Sollew (Desired State)

On the banks of the beautiful River Wah-Hoo

Where they never have troubles! At least, very few.

They jump aboard the adviser's camel, but later encounter unforeseen issues:

So there, there we were in a dreadful position

Our camel now needed a camel physician.

In a familiar twist, our hero ends up carrying both adviser and camel, while the adviser reassurres that:

This is called teamwork.  I furnish the brains

You furnish the muscles, the aches and the pains.

The journey continues with more learning experiences until finally Solla Sollew is reached, only to find that troubles have come to light even in that fabled place and the natives tell our hero:

And I'm off to the city of Boola Boo Ball...

Where they never have troubles! No troubles at all!

The hero thinks of going there, then has second thoughts:

So I started to go

But I didn't.

Instead...

I did some quick thinking

Inside of my head.

He decides to return home and solve his own problems, by obtaining appropriate tools:

I've bought a big bat

I'm all ready, you see

Now my troubles are going

To have troubles with me!

Back in the real world, there are more than two hundred of those 'bats' in DynoChem Resources. 

You can hear all about them from our customers at the DynoChem 2011 Meetings in Mumbai, Chicago and London.

Great Bards of QbD: Lewis Fry Richardson

Integration in time (and space) of the equations of mass, momentum and energy conservation plays a growing role in QbD.  An early contributor to this field was Lewis Fry Richardson, whose 1922 book, Weather Prediction by Numerical Process, laid the basis for modern weather prediction techniques.  Richardson also occupied himself with understanding turbulence and like Corrsin, was briefly moved to write a verse about his ideas.  Corrsin was inspired by Shakespeare; Richardson by Jonathan Swift and Augustus de Morgan to write about the cascade of energy from large to small scales:

  Big whorls have little whorls,
  Which feed on their velocity;
  And little whorls have lesser whorls,
  And so on to viscosity
  (in the molecular sense).

Many subsequent students of turbulence and mixing built on Richardson's work, and the Richardson Number is named in his honour. He also analyzed wars using mathematics and had early ideas about fractals while studying the lengths of shared borders between countries. Recipients of the Lewis Fry Richardson Medal have included Benoit Mandelbrot.

De Morgan had written:

  Great fleas have little fleas upon their backs to bite 'em,
  And little fleas have lesser fleas, and so ad infinitum.
  And the great fleas themselves, in turn, have greater fleas to go on;
  While these again have greater still, and greater still, and so on.

Swift originally wrote (in 1733):

  So, naturalists observe, a flea
  Hath smaller fleas that on him prey;
  And these have smaller still to bite 'em;
  And so proceed ad infinitum.
  Thus every poet, in his kind,
  Is bit by him that comes behind.

Great Bards of QbD: Stanley Corrsin

When we calculate mixing timescales in reactors and crystallizers [Liquid mixing: batch and fed batch mixing times], we leverage the work of Stanley Corrsin, one of many pre-Internet scientists who laid foundations for our predictive abilities.  His paper, [Simple theory of an idealized turbulent mixer,  AIChE Journal, Volume 3, Issue 3, pages 329–330, September 1957] showed how the time constant for mixing depended on the rate of dissipation of turbulent kinetic energy.  

Stanley loved his subject so much that he was moved to poetry.  He is responsible for the following sonnet, inspired by one of Shakespeare's (Sonnet 18 Shall I compare thee to a Summer's day?): 

SONNET TO TURBULENCE by S. Corrsin ^[1]
For Hans Liepmann ^[2] on the occasion of his 70th birthday, with apologies to Bill S. and Liz B.B.

Shall we compare you to a laminar flow?

You are more lovely and more sinuous.

Rough winter winds shake branches free of snow,

And summer’s plumes churn up in cumulus.

How do we perceive you? Let me count the ways.

A random vortex field with strain entwined.

Fractal? Big and small swirls in the maze

May give us paradigms of flows to find.

Orthonormal forms non-linearly renew

Intricate flows with many free degrees

Or, in the latest fashion, merely few —

As strange attractor. In fact, we need Cray 3’s ^[3].

Experiment and theory, unforgiving;

For serious searcher, fun ... and it’s a living!