shear stress


Leaping Shampoo AKA ‘The Kaye Effect’

The Kaye Effect is a property of complex liquids which was first described by the British engineer Alan Kaye in 1963.

While pouring one viscous mixture of an organic liquid onto a surface, the surface suddenly spouted an upcoming jet of liquid which merged with the downgoing one.

This phenomenon has since been discovered to be common in all shear-thinning liquids (liquids which thin under shear stress). Common household liquids with this property are liquid hand soaps, shampoos and non-drip paint. The effect usually goes unnoticed, however, because it seldom lasts more than about 300 milliseconds. The effect can be sustained by pouring the liquid onto a slanted surface, preventing the outgoing jet from intersecting the downward one (which tends to end the effect).

It is thought to occur when the downgoing stream “slips” off the pile it is forming, and due to a thin layer of shear-thinned liquid acting as a lubricant, does not combine with the pile. When the slipping stream reaches a dimple in the pile, it will shoot off it like a ramp, creating the effect.(wiki)


Hymn of Breaking Strain

(by Rudyard Kipling)

The careful text-books measure
   (Let all who build beware!)
The load, the shock, the pressure
   Material can bear.
So, when the buckled girder
   Lets down the grinding span,
The blame of loss, or murder,
   Is laid upon the man.
Not of the Stuff - the Man!

But, in our daily dealing
   With stone and steel, we find
The Gods have no such feeling
   Of justice toward mankind.
To no set gauge they make us, -
   For no laid course prepare -
And presently o'ertake us
   With loads we cannot bear:
       Too merciless to bear.

The prudent text-books give it
   In tables at the end -
The stress that shears a rivet
   Or makes a tie-bar bend -
What traffic wrecks macadam -
   What concrete should endure -
But we, poor Sons of Adam,
   Have no such literature,
       To warn us or make sure!

We hold all Earth to plunder -
   All Time and Space as well -
Too wonder-stale to wonder
   At each new miracle;
Till in the mid-illusion
   Of Godhead ‘neath our hand,
Falls multiple confusion
   On all we did or planned -
       The mighty works we planned.

We only of Creation
   (Oh, luckier bridge and rail!)
Abide the twin-damnation -
   To fail and know we fail.
Yet we - by which sole token
   We know we once were Gods -
Take shame in being broken
   However great the odds -
       The Burden or the Odds.

Oh, veiled and secret Power
   Whose paths we seek in vain,
Be with us in our hour
   Of overthrow and pain;
That we - by which sure token
   We know Thy ways are true -
In spite of being broken,
   Because of being broken,
       May rise and build anew.
       Stand up and build anew!

Using the Power of Space to Fight Cancer

From cancer research to DNA sequencing, the International Space Space is proving to be an ideal platform for medical research. But new techniques in fighting cancer are not confined to research on the space station. Increasingly, artificial intelligence is helping to “read” large datasets. And for the past 15 years, these big data techniques pioneered by our Jet Propulsion Laboratory have been revolutionizing biomedical research.

Microgravity Research on Space Station

On Earth, scientists have devised several laboratory methods to mimic normal cellular behavior, but none of them work exactly the way the body does. Beginning more than 40 years ago aboard Skylab and continuing today aboard the space station, we and our partners have conducted research in the microgravity of space.  In this environment, in vitro cells arrange themselves into three-dimensional groupings, or aggregates. These aggregates more closely resemble what actually occurs in the human body. Cells in microgravity also tend to clump together more easily, and they experience reduced fluid shear stress – a type of turbulence that can affect their behavior. The development of 3D structure and enhanced cell differentiation seen in microgravity may help scientists study cell behavior and cancer development in models that behave more like tissues in the human body.

In addition, using the distinctive microgravity environment aboard the station, researchers are making further advancements in cancer therapy. The process of microencapsulation was investigated aboard the space station in an effort to improve the Earth-based technology. Microencapsulation is a technique that creates tiny, liquid-filled, biodegradable micro-balloons that can serve as delivery systems for various compounds, including specific combinations of concentrated anti-tumor drugs. For decades, scientists and clinicians have looked for the best ways to deliver these micro-balloons, or microcapsules, directly to specific treatment sites within a cancer patient, a process that has the potential to revolutionize cancer treatment.

A team of scientists at Johnson Space Center used the station as a tool to advance an Earth-based microencapsulation system, known as the Microencapsulation Electrostatic Processing System-II (MEPS-II), as a way to make more effective microcapsules. The team leveraged fluid behavior in microgravity to develop a new technique for making these microcapsules that would be more effective on Earth. In space, microgravity brought together two liquids incapable of mixing on Earth (80 percent water and 20 percent oil) in such a way that spontaneously caused liquid-filled microcapsules to form as spherical, tiny, liquid-filled bubbles surrounded by a thin, semipermeable, outer membrane. After studying these microcapsules on Earth, the team was able to develop a system to make more of the space-like microcapsules on Earth and are now performing activities leading to FDA approval for use in cancer treatment.  

In addition, the ISS National Laboratory managed by the Center for the Advancement of Science in Space (CASIS) has also sponsored cancer-related investigations.  An example of that is an investigation conducted by the commercial company Eli Lilly that seeks to crystallize a human membrane protein involved in several types of cancer together with a compound that could serve as a drug to treat those cancers. 

“So many things change in 3-D, it’s mind-blowing – when you look at the function of the cell, how they present their proteins, how they activate genes, how they interact with other cells,” said Jeanne Becker, Ph.D., a cell biologist at Nano3D Biosciences in Houston and principal investigator for a study called Cellular Biotechnology Operations Support Systems: Evaluation of Ovarian Tumor Cell Growth and Gene Expression, also known as the CBOSS-1-Ovarian study. “The variable that you are most looking at here is gravity, and you can’t really take away gravity on Earth. You have to go where gravity is reduced." 

Crunching Big Data Using Space Knowledge

Our Jet Propulsion Laboratory often deals with measurements from a variety of sensors – say, cameras and mass spectrometers that are on our spacecraft. Both can be used to study a star, planet or similar target object. But it takes special software to recognize that readings from very different instruments relate to one another.

There’s a similar problem in cancer research, where readings from different biomedical tests or instruments require correlation with one another. For that to happen, data have to be standardized, and algorithms must be “taught” to know what they’re looking for.

Because space exploration and cancer research share a similar challenge in that they both must analyze large datasets to find meaning, JPL and the National Cancer Institute renewed their research partnership to continue developing methods in data science that originated in space exploration and are now supporting new cancer discoveries.

JPL’s methods are leading to the development of a single, searchable network of cancer data that researcher can work into techniques for the early diagnosis of cancer or cancer risk. In the time they’ve worked together, the two organizations’ efforts have led to the discovery of six new Food and Drug Administration-approved cancer biomarkers. These agency-approved biomarkers have been used in more than 1 million patient diagnostic tests worldwide.

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The Physics of Sliding on Ice

by Gabriel Popkin, Inside Science

For a solid material, ice is strangely slippery. While Olympic skiers and children on a snowy hill may or may not care why their favorite winter activities are physically possible, the question has bedeviled scientists for more than a century. Ice is “one of the most complicated” materials, said physicist Bo Persson of Forschungszentrum Jülich in Germany. “It behaves strangely compared to other materials.”

A new study published by Persson in the Journal of Chemical Physics provides a mathematical foundation for hypotheses that a liquid-like form of water on the ice surface accounts for its slickness.

The finding could aid designers of winter sports gear who want to increase sliding on ice, and tire designers who want to minimize it. It could also help experimental scientists who have measured ice friction but have not been able to fully explain their results.

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Forcing fluid through an orifice and into an immiscible fluid causes the fluid to break up into drops due to surface tension. Drops are formed either at the end of the orifice or at the end of a jet depending on fluid parameters such as viscosity, flow rate, and interfacial tension. While drop formation in air is well understood, researchers are interested in what happens with drop formation in fluids for applications such as microfluidics and extrusion emulsification. To study the transition between dripping and jetting regimes, researchers use the capillary number, a dimensionless parameter describing the ratio between viscous forces and interfacial tension. They discovered that for capillary numbers less than one, surface tension dominates, and the system drips. By contrast, when the capillary number is greater than one, the shear stress on the drop is large enough to overcome surface tension effects causing drops to form in the jetting regime. This is shown in the figure and plot above. The plot is Weber number of the inner fluid vs Capillary number of the outer fluid. (Figure and plot credit: A. S. Utada et al, PRL 99,094502 (2007))

Glass Gets Stronger By Cracking It

by Txchnologist staff

Engraving microscopic cracks in glass sheets can make it 200 times tougher than normal, McGill University mechanical engineers say. The insight could lead to improvements in regular glass objects like wine glasses or jars that don’t shatter when dropped, instead only deforming on impact.

Researchers took a clue from nature to uncover the fact that etching wavy lines in test glass slides prevented stress-induced cracks from spreading into the material’s failure. Their muse was the seemingly simple mother-of-pearl coating inside the shells of some mollusks.

This material is called nacre, and it is mostly composed of chalk, a brittle substance that normally disintegrates under the slightest pressure. But the organism constructs a biomaterial that is 3,000 times tougher than the weak chalk from which it is composed, writes François Barthelat, who runs McGill’s biomimetic materials lab and led the research. The secret is in how the creature builds nacre out of tiny tablets of chalk that are laid down in offset rows. This architecture, which is also seen in teeth and bones, counters a propagating crack by deflecting it and diffusing energy to surrounding tiles.

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Hey, welcome back to Ballet AU. Please see the awesome that is amatterofcomplication’s masterpost for how this craziness began and progressed, and please see my own Fluidity, Rotation, Momentum, Prismatic, Turbulence, and Phase for how this particular story got to this particular point. Disclaimer 1: This is not as sweet as last time. Disclaimer 2: There is some unprecedentedly (for me) foul language herein; I sort of apologize, but the new character will say what the new character wants to say. This particular new character has been in the works for some time, as both tracybering and amatterofcomplication better be willing to swear to in court, if asked… anyway, this is a two-parter, because there is a lot going on. Second part will be up tomorrow or the next day, depending on how quickly I can get some last bits of dialogue to shake as they should.


Myka picks up the ringing phone and says hello absently; Claudia’s already left for the day, and Myka’s trying to make her way through a couple of research reports on microfibers before she herself heads for home.

“Hey, Myka!” Steve says. He’s usually a pretty cheerful guy, but his tone is far too enthusiastic to be real.

“Hey, Steve,” Myka responds, a bit hesitantly. It’s odd for him to be calling her here. “What’s happening?”

“Well, here’s the thing. You know how in the military, they say DefCon whatever number to show how bad the situation is?”


“Well, Mrs. Frederic might have called Helena in a while ago.”


“And I think it’s pretty safe to say that the DefCon is basically not countable.”

Liam, in the background, says, “Tell her that crazy Giselle is looking for an ax.”

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Ig Nobel winners 2015

CHEMISTRY PRIZE — Callum Ormonde and Colin Raston [AUSTRALIA], and Tom Yuan, Stephan Kudlacek, Sameeran Kunche, Joshua N. Smith, William A. Brown, Kaitlin Pugliese, Tivoli Olsen, Mariam Iftikhar, Gregory Weiss [USA], for inventing a chemical recipe to partially un-boil an egg.
REFERENCE: “Shear-Stress-Mediated Refolding of Proteins from Aggregates and Inclusion Bodies,” Tom Z. Yuan, Callum F. G. Ormonde, Stephan T. Kudlacek, Sameeran Kunche, Joshua N. Smith, William A. Brown, Kaitlin M. Pugliese, Tivoli J. Olsen, Mariam Iftikhar, Colin L. Raston, Gregory A. Weiss, ChemBioChem, epub January 2015.
WHO ATTENDED THE CEREMONY: Callum Ormonde, Tivoli Olsen, Colin Raston, Greg Weis

PHYSICS PRIZE — Patricia Yang [USA and TAIWAN], David Hu [USA and TAIWAN], and Jonathan Pham, Jerome Choo [USA], for testing the biological principle that nearly all mammals empty their bladders in about 21 seconds (plus or minus 13 seconds).
REFERENCE: “Duration of Urination Does Not Change With Body Size,” Patricia J. Yang, Jonathan Pham, Jerome Choo, and David L. Hu, Proceedings of the National Academy of Sciences, 2014: 201402289.
WHO ATTENDED THE CEREMONY: Patricia Yang, David Hu, Jonathan Pham, Jerome Choo

LITERATURE PRIZE — Mark Dingemanse [THE NETHERLANDS, USA], Francisco Torreira [THE NETHERLANDS, BELGIUM, USA], and Nick J. Enfield [AUSTRALIA, THE NETHERLANDS], for discovering that the word “huh?” (or its equivalent) seems to exist in every human language — and for not being quite sure why.
REFERENCE: “Is ‘Huh?’ a universal word? Conversational infrastructure and the convergent evolution of linguistic items,” Mark Dingemanse, Francisco Torreira, and Nick J. Enfield, PLOS ONE, 2013.
WHO ATTENDED THE CEREMONY: The authors were unable to attend the ceremony; they sent a video acceptance speech. They will receive their prize at an at a special event in Amsterdam, The Netherlands on October 3: The European Ig Nobel Show

MANAGEMENT PRIZE — Gennaro Bernile [ITALY, SINGAPORE, USA], Vineet Bhagwat [USA], and P. Raghavendra Rau [UK, INDIA, FRANCE, LUXEMBOURG, GERMANY, JAPAN], for discovering that many business leaders developed in childhood a fondness for risk-taking, when they experienced natural disasters (such as earthquakes, volcanic eruptions, tsunamis, and wildfires) that — for them — had no dire personal consequences.
REFERENCE: “What Doesn’t Kill You Will Only Make You More Risk-Loving: Early-Life Disasters and CEO Behavior,” Gennaro Bernile, Vineet Bhagwat, and P. Raghavendra Rau, Asian Finance Association (AsianFA) 2015 Conference Paper. Accepted for publication in the Journal of Finance. Available at SSRN 2423044.
WHO ATTENDED THE CEREMONY: Gennaro Bernile and P. Raghavendra Rau

ECONOMICS PRIZE — The Bangkok Metropolitan Police [THAILAND], for offering to pay policemen extra cash if the policemen refuse to take bribes.
REFERENCE: Numerous news reports.

MEDICINE PRIZE — Awarded jointly to two groups: Hajime Kimata [JAPAN, CHINA]; and to Jaroslava Durdiaková [SLOVAKIA, US, UK], Peter Celec [SLOVAKIA, GERMANY], Natália Kamodyová, Tatiana Sedláčková, Gabriela Repiská, Barbara Sviežená, and Gabriel Minárik [SLOVAKIA], for experiments to study the biomedical benefits or biomedical consequences of intense kissing (and other intimate, interpersonal activities).
REFERENCE: “Kissing Reduces Allergic Skin Wheal Responses and Plasma Neurotrophin Levels,” Hajime Kimata, Physiology and Behavior, vol. 80, nos. 2-3, November 2003, pp. 395-8.
REFERENCE: “Reduction of Allergic Skin Weal Responses by Sexual Intercourse in Allergic Patients,” Hajime Kimata, Sexual and Relationship Therapy, vol 19, no. 2, May 2004, pp. 151-4.
REFERENCE: “Kissing Selectively Decreases Allergen-Specific IgE Production in Atopic Patients,” Hajime Kimata, Journal of Psychosomatic Research, vol. 60, 2006, pp. 545– 547.
REFERENCE: “Prevalence and Persistence of Male DNA Identified in Mixed Saliva Samples After Intense Kissing,” Natália Kamodyová, Jaroslava Durdiaková, Peter Celec, Tatiana Sedláčková, Gabriela Repiská, Barbara Sviežená, and Gabriel Minárik, Forensic Science International Genetics, vol. 7, no. 1, January 2013, pp. 124–8.
WHO ATTENDED THE CEREMONY: Jaroslava Durdiaková and Peter Celec will be at the ceremony. Hajime Kimata will be at the Ig Informal Lectures, on Saturday, Sept 19 (a prior commmitment prevented him from attending the Thursday ceremony); he sent a video acceptence speech which was played at the Thursday night ceremony.

MATHEMATICS PRIZE — Elisabeth Oberzaucher [AUSTRIA, GERMANY, UK] and Karl Grammer [AUSTRIA, GERMANY], for trying to use mathematical techniques to determine whether and how Moulay Ismael the Bloodthirsty, the Sharifian Emperor of Morocco, managed, during the years from 1697 through 1727, to father 888 children.
REFERENCE: “The Case of Moulay Ismael-Fact or Fancy?” Elisabeth Oberzaucher and Karl Grammer, PLOS ONE, vol. 9, no. 2, 2014, e85292.
WHO ATTENDED THE CEREMONY: Elisabeth Oberzaucher

BIOLOGY PRIZE — Bruno Grossi, Omar Larach, Mauricio Canals, Rodrigo A. Vásquez [CHILE], José Iriarte-Díaz [CHILE, USA], for observing that when you attach a weighted stick to the rear end of a chicken, the chicken then walks in a manner similar to that in which dinosaurs are thought to have walked.
REFERENCE: “Walking Like Dinosaurs: Chickens with Artificial Tails Provide Clues about Non-Avian Theropod Locomotion,” Bruno Grossi, José Iriarte-Díaz, Omar Larach, Mauricio Canals, Rodrigo A. Vásquez, PLoS ONE, vol. 9, no. 2, 2014, e88458. [NOTE: The paper is accompanied by a video.>
WHO ATTENDED THE CEREMONY: Bruno Grossi, José Iriarte-Díaz, Omar Larach, Rodrigo A. Vásquez

DIAGNOSTIC MEDICINE PRIZE — Diallah Karim [CANADA, UK], Anthony Harnden [NEW ZEALAND, UK, US], Nigel D'Souza [BAHRAIN, BELGIUM, DUBAI, INDIA, SOUTH AFRICA, US, UK], Andrew Huang [CHINA, UK], Abdel Kader Allouni [SYRIA, UK], Helen Ashdown [UK], Richard J. Stevens [UK], and Simon Kreckler [UK], for determining that acute appendicitis can be accurately diagnosed by the amount of pain evident when the patient is driven over speed bumps.
REFERENCE: “Pain Over Speed Bumps in Diagnosis of Acute Appendicitis: Diagnostic Accuracy Study,” Helen F. Ashdown, Nigel D'Souza, Diallah Karim, Richard J. Stevens, Andrew Huang, and Anthony Harnden, BMJ, vol. 345, 2012, e8012.
WHO ATTENDED THE CEREMONY: Diallah Karim, Anthony Harnden, Helen Ashdown, Nigel D'Souza, Abdel Kader Allouni

PHYSIOLOGY and ENTOMOLOGY PRIZE — Awarded jointly to two individuals: Justin Schmidt [USA, CANADA], for painstakingly creating the Schmidt Sting Pain Index, which rates the relative pain people feel when stung by various insects; and to Michael L. Smith [USA, UK, THE NETHERLANDS], for carefully arranging for honey bees to sting him repeatedly on 25 different locations on his body, to learn which locations are the least painful (the skull, middle toe tip, and upper arm). and which are the most painful (the nostril, upper lip, and penis shaft).
REFERENCE: “Hemolytic Activities of Stinging Insect Venoms,” Justin O. Schmidt, Murray S. Blum, and William L. Overal, Archives of Insect Biochemistry and Physiology, vol. 1, no. 2, 1983, pp. 155-160.
REFERENCE: “Honey Bee Sting Pain Index by Body Location,” Michael L. Smith, PeerJ, 2014, 2:e338.
WHO ATTENDED THE CEREMONY: Justin Schmidt and Michael Smith


Experimental geology can be quite neat. This is a box filled with gypsum powder under a shear stress. You can watch as first a series of fractures form at about 30 degrees to the strongest stress direction and then they connect, localizing into a strike slip fault.