Thursday, August 26, 2010

Quotation of the Moment

"Lisa, in this house, we obey the laws of thermodynamics!"

Homer Simpson, after Lisa builds a perpetual motion machine
(Episode: The PTA Disbands)

You Cannot Change the Laws of Physics, Captain

Brooks Sports is advertising its new cushioning system by highlighting its viscoelastic properties.  The new system (called DNA [1]) uses a "highly-viscous non-Newtonian fluid."  The shock absorber uses a semi-liquid filling instead of a semi-solid filling.  The company blog interviews a material engineer who talks a little about basic non-Newtonian behavior.  He uses ketchup as an example.  So far, so good.

The web page that discusses the technology (link here) does have a mistake.  In the video at the bottom of the page, the material engineer states that a "non-Newtonian fluid does not obey the laws of physics." [2,3]

It is precisely because a non-Newtonian fluid obeys the laws of physics that we observe unusual physical behavior like shear-thinning or shear-thickening.  A fluid that did not obey the laws of physics would defy gravity, or it would spontaneously separate into its individual elemental components.  

[1]  I could not find an explanation for this abbreviation.
[2]  Brooks is traveling the country with a vat of cornstarch and water advertising the new technology.  For other videos of shear-thickening behavior, go here.
[3]  I left a comment on the Brooks blog, but either it was not approved, or was removed.

Monday, August 23, 2010

Shear Thinning in Xenon

While poking around the web, I found this post, which described the CVX-2 viscometer, which was designed to test the shear-thinning properties of xenon near the critical point.  It's much easier to maintain the fluid at the critical point in the absence of gravity.  A paper describing the results was published in Phys. Rev. E [subscription required].
The experiments found evidence of shear-thinning behavior, which confirms the predictions of dynamic mode-coupling theory.  The viscometer flew on the Columbia's final mission.  Fortunately, the data were beamed to earth before the accident, and a hard drive with the data was recovered from the wreckage.

Sunday, August 22, 2010

Back to Regular Programming

Work has returned to a slower pace, so I should be able to resume my regular blogging routine.  I seem to average about a post every second or third day, and I wind up with about 15 posts per month.
Thanks again for stopping by.

Wednesday, August 18, 2010

Rheologist Job at Kraft

The SOR advertised a position at Kraft Foods through its email list last week.  I looked up the job description at Kraft Foods, and here it is.

The Scientist-Rheology position provides an excellent opportunity to build and apply scientific and rheological expertise to a wide range of leading food products and related food systems in a fast-paced rewarding environment.

Key responsibilities include the following:
•Leverage a strong Rheology and scientific understanding to support various R and D projects for a broad range of food systems
•Apply current and develop new and innovative rheological approaches and understanding to solve practical problems
•Develop and apply a broad physical characterization expertise
•Develop and apply ingredient, formulation and process understanding governing rheology and texture of food systems
•Collaborate across R and D as a cross-functional team member and develop technical leadership
•Communicate effectively technical findings to project team and management - maintain lab notebook, write technical reports and present project summaries
•Build, maintain and leverage strong internal and external network of technical experts

Qualified candidates should possess the following:
•Highly motivated PhD in Engineering or Sciences with a strong proven expertise in Rheology
•1-2 years of postdoctoral or industrial experience will be a plus
•Demonstrated in-depth understanding in two or more of the following areas: Polymer Science, Colloid/Emulsion Sciences, Physical Chemistry, and Process Engineering
•Strong experimental skills, with a talent to apply scientific findings to solve practical problems
•Passion to apply multi-disciplined background to Food Industry
•Excellent interpersonal and project management skills
•Excellent written and verbal communication skills
•Ability to build strong customer/client relationships

Primary Location : NA-US-IL-Glenview

Interestingly, this position cannot be found using my standard keyword search rheolog* on

The job, as advertised, is similar to my job at ConAgra.  (I'm not planning to apply for the job; I'm doing fine at my current position.)

Disclosure: ConAgra competes against Kraft  in a variety of markets.

Tuesday, August 17, 2010

Another Accidental Discovery

Another accident that led to an important product was the discovery of polytetrafluoroethylene.  While attempting to develop a new refrigerant, perfluoroethelyne polymerized inside a pressurized container.

Brilliant Screw Ups

The Mental Floss blog details 8 screw-ups that led to important scientific discoveries.  It turns out that researchers at DuPont were playing around when the boss was out when they discovered the nylon rope trick.

And, for those who just can't clean up after themselves and need justification for their managers, the discoveries of penicillin and photography were accomplished by messy scientists.

Thursday, August 12, 2010

Link of the Moment: Aspen Research

A few months ago, someone asked what rheology was like from the industrial perspective.  John Spevacek from the Rheo Thing blog writes up a description of his job and company here.

Friday, August 6, 2010

Quotation of the Moment: Romy & Michele

In honor of the 30th anniversary of the Post-It note, I present this quotation.
"No. Um, well, ordinarily when you make glue first you need to thermoset your resin and then after it cools you have to mix in an epoxide, which is really just a fancy-schmancy name for any simple oxygenated adhesive, right? And then I thought maybe, just maybe, you could raise the viscosity by adding a complex glucose derivative during the emulsification process and it turns out I was right."
From Romy and Michele's High School Reunion

According to IMDb, this is one of five movies that uses the word viscosity in the screenplay.  The book ReAction!: Chemistry in the Movies by Griep and Mikasen says this movie covers the chemistry of sticky notes.

Wednesday, August 4, 2010

A Pointless Anecdote

One of my old bosses had a particular tic: whenever someone would make an announcment that would require a follow up, he would state "oh," to show that he was paying attention.
One day, I noticed that a particular letter had dropped off the sign in front of our building.  I picked up the letter, brought it to his office and said,
"I have something to show you."
"Oh?" he replied.
"Exactly!" I responded, placing the letter o on his desk.
He never mentioned the incident, and I wonder how he felt about one of his tics being used to play a joke on him.

Monday, August 2, 2010

Jobs Report (August)

A search using the keyword "rheolog*" found 29 job postings on August 1st.  The posting date ranges are as follows--
  • 7 within the last 3 days
  • 10 within the last 7 days (so, 3 were posted 4-7 days ago)
  • 10 within the last 14 days (none posted 8-14 days ago)
  • 18 within the last 30 days (8 posted 15-30 days ago)
  • 29 within the last 60 days (9 posted 31-60 days ago)