Droplet Dancing

These guys from Stanford did some surface tension research with water and polyethylene glycol (PG).  Watch the video.  My favorite is when they use sharpies to make a hydrophobic barrier and sort different coloured (with different concentrations of PG) to sort the droplets.  The video show specifically how the water and PG droplets interact with each other and surrounding vapour on a glass surface.   Chasing, sorting and other events take place in this awesome soundtracked video.

The Surface Tension Principles in Splashback

There is a great episode of Curb Your Enthusiasm where Larry David has to pee at his employee's home.  He is taking a drug that makes him pee like a race horse and subsequently he gets splash back.  Of course he could have sit down as he does in other episodes but this would not be as funny and make a good story.  So standing he gets splashback and some of that goes onto a painting of Jesus on the wall next to the toilet.  Jesus looks like he is crying and Catholics once again to believe in miracles.  Someone should teach them about surface tension as well.  However, this phenomenon of splashback is only recently being understood by some American scientists.


The team used high speed cameras and filmed jets of artificial piss striking toilet walls and spraying back.   The team used different angles and changed the distance from the toilet and determined that closeness and angle of the attack reduced the splash back.

Firstly it depends largely on the distance.  When a guy starts to pee droplets are made right away coming out of the urethra due to a phenomenon called the Plateau-Rayleigh instability in which a falling stream breaks into smaller packets with the same volume but reduces the surface area due to the liquid wanting to minimise the surface area.  This phenomenon is evident in ink jet and electrospray technology in Mass Spectrometry instruments.  To control the distance obviously a man could sit down to pee and in the above example with Larry David occasionally he does do this as mentioned in other episodes.

Also changing the angle helps as well to deal with the surface tension affects caused by scattering.  For example if you aimed directly at the water (as it seems in the above video that Larry David did) you will have a nasty splashback.  However, if you aim at the bowl which have a very hydophilic surface it may help a little.  The best is likely a tried and tested technique of adding some toilet paper to soften the blow.  Ultimately, it will be better to make superhydrophobic coatings that will make droplets on the surface and roll off before splashing back.

I am not clear whether the surface tension of the urine (which varies from   55 - 62 mN/m) plays a significant factor in the splashback and how the difference between the surface tension of the lower droplets are affected by the surface tension of the bulk water in the toilet.    The surface tension is lowered by the bile fats, the urea and some small proteins that are excreted.    Potentially pee which has a higher surface tension would give more splashback.  




Six Techniques to Reduce Back Splash 

1. Get close and make a smooth unbroken stream.  
2. Angle downwards or sideways instead of straight (for urinals especially)  if the urinal has a fly, aim for it.
3. Add some toilet paper
4. Hydrophobic coatings for toilets 
5. Sit down to pee.
6. Push it all out at once and be weary of the end of the stream

If regular water was replaced with heavy water...

That is a great question that was recently answered in Gizmodo.  Since water is necessary for all life one mass unit it does really affect everything.  Since the surface tension is a property of water a change from light water to heavy water would increase give creatures like water skimmer, ants and other animals that follow the Jesus number a harder time.  

Cocktail novelties inspired by nature’s designs - MIT News Office

Cocktail novelties inspired by nature’s designs - MIT News Office


My two favourite things science and food have merged to make a awesome drink accessory.  The Spanish chef Jose Andres who trained under the molecular gastronomist chef Ferran Adria at El Bulli has made a number of restaurants around the US.  Now he has used his culinary skills and of course some science perhaps learned from his predecessor to make this cocktail boat that uses surface tension.  

Bio-friendly micro-motors propelled by polymers

http://www.youtube.com/v/It24DGnotCk?version=3&autohide=1&showinfo=1&autoplay=1&autohide=1&attribution_tag=6mW4yOUGvJaBB4tkHvR-zg&feature=share

Biofriendly Micromotors kickass!  Using a big surface tension gradient is a way to move things really fast.  The motor works by releasing surfactants on one side of the motor after a depolyerization event then moves away from the exhaust of this surfactants then repeats the event.

The Science Behind the Number 1 (Peeing, Math and Surface Tension)

Watch 'Intelligent' Blobs Sort Themselves by Surface Tension | MIT Technology Review

Watch 'Intelligent' Blobs Sort Themselves by Surface Tension | MIT Technology Review

Water impurities key to an icicle's ripples

Water impurities key to an icicle's ripples

News: How slippery are water-repellent surfaces? - Aalto University

News: How slippery are water-repellent surfaces? - Aalto University

DNA Funtime: How to Stretch DNA and Put It Anywhere You Want (sort of)

DNA Funtime: How to Stretch DNA and Put It Anywhere You Want (sort of)

Fluid in Pictures

The beauty of fluids captured.... Surface tension at its best....

Ancient Water Clocks

 In order to maintain time in this era people used water clocks.  This was a revelation.  These early clocks were used to keep the time to maintain both customer satisfaction and maximum profit.  Like many things the Greek's invented or used like the Olympics, Democracy, Philosophy, Mechanical computer, math,  and prostitution, the water clock spread to the rest of the world.

Water clocks were an example of early innovation made in different parts of the world with China, Egypt, Babylon, India and eventually Greece utilizing them for time and astrology.   The earliest water clocks used by the Greeks were simple.  Water was filled in a bowl or a clepsydra to the top and a spout led to another bowl which counted the time in hours with markings.  The water would flow out slower when the pressure decreased so they made special markings on the receiving bowl to account for this.  This was only a timer though.  The Greeks made these simple to measure the time for defence of a court case or for example your time paid for with a prostitute.  Several physical factors made these clocks and the future water clocks not precise.

The physical phenomena of gravity, viscosity and surface tension allows for the water clock to maintain a more precise time (although not in today's standards).  The flow rate is inversely proportional to the viscosity both of which is dependent on the temperature.  The surface tension affects the meniscus on the incoming water so an hour would never be really precise at the different temperatures (for example the water would run seven times faster at 100 C than at 0 C).  The surface tension of the water would also affect the later made mechanical clocks which did not rely on a constant flow but rather added the water to another tank in drops.  So any dust, soap, change in temperature could make the clock a lot slower.    

Water Ideal Lubricant for Nanomachines

Making nanomachines?  Need a lubricant?  Try water.  Researchers in Amsterdam did!

'Researchers from the University of Amsterdam have discovered that machines just one molecule in size move far quicker if you add a 'lubricant' to their surroundings. To their surprise, water proved to be the best lubricant by far.'  The hydrogen bonding and surface tension properties of water are likely the cause.  


Read more at: http://phys.org/news/2013-08-ideal-lubricant-nanomachines.html#jCp

Futuristic Concept Cleans Your House With Robot Flies

Futuristic Concept Cleans Your House With Robot Flies

Step 1 is important:

Mixes the water and a substance that gives a higher surface tension and a pleasant odor to the water.  This allows these 908 robotic flies to collect dirt easier on the surface of the floor or wherever.  

Kibron's instruments help to optimise this substance (soap, detergent, surfactant, polymer) to give the best surface tension for better cleaning now... and in the future....

Sequencing DNA with Surface Tension

 A new technique, known as molecular threading, now lets researchers grab onto a single gnarled strand of DNA in solution, draw it out into thin air, and neatly fix it to a substrate where it can be accessed.  Using Poly(methyl methacrylate) a thermoplastic hydrophobic material they can pull the DNA from a tiny drop like it is a string in your hand.  

Check it out here:

http://www.extremetech.com/extreme/165483-molecular-threading-a-powerful-tool-for-dna-sequencing

and the original article here:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0069058

Rethinking Surface Tension

A new paper uncovers the surface tension in solids.
http://phys.org/news/2013-08-rethinking-surface-tension.html

The Jesus Number and How to walk on Water

http://io9.com/how-to-walk-on-water-1120861771


This video gives an account of all the different ways insects (mostly) can use their low body weight, number of legs and in some case chemicals to walk on water.  There are 1 million insect species and only about 0.1% can walk on water.  Likely most can stand on water.  This is dictated by the size of the insect (or other creature) aptly called the Jesus number.  

Painting with Toxic Sludge

Toxic sludge paint?  The surface tension is important for any kind of paint to work on whatever canvas you are using.  But how about all the stuff that we pour down our sinks.  Could that work?  One artist tried it.  Here are the results.

Computing the Physics of Bubbles

Computing the Physics of Bubbles

I think I repeated this article....

Superfluid turbulence through the lens of black holes - MIT News Office

Superfluid turbulence through the lens of black holes - MIT News Office

Without hindrance from surface tension or gravity superfluid behaves like cigarette smoke.

Just Clap Your Hands for Surface Tension

Understanding how fluids are working is explained in this article.

Tractor beam produced with unstructured light - physicsworld.com

Tractor beam produced with unstructured light - physicsworld.com


Unfortunately, the surface tension is too strong to free the object from the surface.  Maybe in space this might work better.

Royal Society of Chemistry on Inks

Here is 10 year old article on inks from the Royal Society of Chemistry about inks.  Know your surface tension and your surface tension measuring devices to make better the best inks!

Chemical analysis in a drop: a dynamic surface tension detector for polymer and protein characterization Bramanti 2013 Polymer International Wiley Online Library

Chemical analysis in a drop: a dynamic surface tension detector for polymer and protein characterization Bramanti 2013 Polymer International Wiley Online Library

Self-assembly of magnetic droplets on a superhydrophobic surface

Switchable Static and Dynamic Self-Assembly of Magnetic Droplets on Superhydrophobic Surfaces

1. Jaakko V. I. Timonen, 
2. Mika Latikka, 
3. Ludwik Leibler, 
4. Robin H. A. Ras, 
5. Olli Ikkala

http://www.sciencemag.org/content/341/6143/253.full

http://motherboard.vice.com/blog/these-high-speed-snapshots-of-water-droplets-are-natures-kaleidoscope

Watermark Ink device gets the ‘Innovation Oscar’ - E & T Magazine

Watermark Ink device gets the ‘Innovation Oscar’ - E & T Magazine

Kinda cool from some Harvard nerds.

The Taylor Cone and Making a Better Mist for ESI-MS

Sir Geoffrey Ingram Taylor in 1964 made the Taylor cone.  His main interest is to see the effect of water droplets in electrical fields (e.g. why water might have a certain shape if there is a lightning strike).  To test this he made the right dimensions for a cone for small amounts of water to flow out.  It is basically a cone with convex sides a rounded tip and a hole that allow water to be pushed out of it.  Nothing interesting so far (especially now since we have seen many of these cones on different products).  The interesting thing is when you apply a electric threshold voltage around this cone.

The term Taylor cone can specifically refer to the theoretical limit of a perfect cone of exactly the predicted angle or generally refer to the approximately conical portion of a cone-jet after the electrospraying process has begun.


The surface tension of the water is key in this as it is holding the individual droplets together to make a cone.  When the water is exposed to an electric field it starts to deform in shape caused by the exposure the surface tension alone.  To make the perfect cone the shape of the outlet tube has to be the correct dimensions.  Two assumptions were made to achieve this:  i) the surface of the cone is equipotential and 2)  as well as a particular radius to counter the surface tension to produce the cone.  When a certain threshold of voltage has been reached the slightly rounded tip inverts and emits a jet of liquid.  This cone jet is the beginning of the electrospraying process.


The electrospray process one of the key developments in Mass Spectrometry.  In order to record the masses of individual molecules you need to get this mist to smaller and smaller droplets (droplet fission) until only the solvent and molecule are left.  After pumping the solvent out using a vacuum, only the molecules of interest are left.  And then you can detect them.  The electrospray technique was later described by Dole and later by Fenn to produce the electrospray ionization technique.

Taken from Wikipedia Kkmurray under creative commons licence

file://localhost/Users/christiancode/Desktop/300px-Taylor_cone-1.jpg

Next Big Future: Rice lab creates sub-10-nanometer graphene nanorib...

Next Big Future: Rice lab creates sub-10-nanometer graphene nanorib...: Rice University shows how water makes it practical to form long graphene nanoribbons less than 10 nanometers wide!

In this case they use the surface tension of the meniscus to protect the tiny ribbon of graphene from being removed during the rest of the process. 

Giant Surfactants, Surface Tension and Self-Organizing Chips

Bee with me - the surface tension involved in honeycombs

Check this article out!

Behavior of turbulent flow of superfluids is opposite that of ordinary fluids

Behavior of turbulent flow of superfluids is opposite that of ordinary fluids

Upstream Flowing Chalk Particles

Surface tension is the key in all this!  Read more here, I am on vacation and don't feel like writing...  I will write later as it has something to do with such a great drink from Argentina!

PopScience

Avanti Polar Lipids - Super G Balance

Avanti Polar Lipids - Super G Balance

Great balance for measuring lipid stocks before doing a monolayer experiment.

Surface Tension Droplets at 2500fps - The Slow Mo Guys

Just water (with its amazing properties), a slow motion camera and two Englishmen.  See what happens...

Droplet Collisions at 5000fps - The Slow Mo Guys

I love the Slow Mo guys.  Showing that surface tension can be sexy!

Quantum model helps solve mysteries of water

Quantum model helps solve mysteries of water

These guys from the University of Edinburgh and IBM's TJ Watson Research Center are made a new model to understand the properties of water.  Since there is no ultimate model but models that can reproduce certain aspects of water these scientists made a bottom up approach.

Their approach shows how a single charged particle called a 'quantum Drude oscillator' can mimic that way electrons of real water respond to their environment and fluctuate.

This simplification allows the network of hydrogen bonds and other properties like surface tension to be observed.

Study led by George Washington University Professor May Help Understand Freezing Bulk Water

Study led by George Washington University professor provides better understanding of water's freezing behavior at nanoscale 

Bulk water verses the water at the surface.  Is there a difference?  And where is the boundary of this difference.  These guys show that ice nucleation at the nanoscale is smaller than that of the bulk water.  Water at the small scale can no longer be considered bulk water.

This has important research in climate.  Clouds largely contain a lot of water.  This research may answer the question of whether ice nucleation occurs within the cloud or right at the surface.  Engineering may be able to control this nucleation by tuning the surface tension if the nucleation occurs on the surface of the cloud (it reminds me of Storm controlling the weather in X-Men).

Bill Nye Teaches About Surface Tension

I remember watching Bill Nye when I was younger and learning about science.  From this post from Mashable I learned that Rush Limbaugh said, '"Bill Nye is not a scientist. Bill Nye can explain to kids things like surface tension, why you can fill a glass above the rim and it won't fall over if it's just the right amount. He explains things like that, surface tension. He's not a scientist. He knows it, and everybody else knows it. Doesn't matter."  Well teaching kids anything about science and having passion about it is far better than whatever bullshit Rush Limbaugh spews out of his  mouth. 

Personally, I would love to see Bill Nye work with Tesla or Elon Musk on the Hyperloop.  Bill Nye has a degree in hydraulic engineering and works with cool space stuff.  Well that is what I would say during an interview to build something called a Hyperloop.  

‘Lotus effect’ paper repels oil and water

‘Lotus effect’ paper repels oil and water
Lotus leaf effect from paper can help make sustainable materials....

Spheres can form squares

Spheres can form squares

How to make fit a square peg into a round hole?  If you are using spherical micrometer sized particles that are colloids and have an oil water interface you might want to adjust the surface tension.  You can minimize the surface of these spherical particles to make a more compact square like stackable structure by placing these particles on a curved oil-water surface e.g. the meniscus.  The same effect is observed in your bowl of Cheerios (cereal) and is called the Cheerio effect.  It has been suggested to be used to see the self assembly of small structures (likely how evolution first started in reactions of dirty volcanic ponds).

Better understanding of water's freezing behavior at nanoscale

Better understanding of water's freezing behavior at nanoscale

They say that 'engineering approaches may be able to be taken to tune the surface tension of water so that the ice crystallization rate can be controlled.'  How would that be?  Adding an external current, nucleation, what....?

Soft matter offers new ways to study how ordered materials arrange themselves

Soft matter offers new ways to study how ordered materials arrange themselves

"When you are making the toroid, the forces on the needle are large enough that the surrounding material behaves as a fluid," he explained. "Once you stop, the elasticity of the outside fluid overcomes surface tension and that freezes the structure in place."

Making Doughnuts shape droplets out of liquids is really cool... mmmmmm...Doughnuts.  

Fabric channels lab-on-a-chip ideas to remove sweat | News | The Engineer

Fabric channels lab-on-a-chip ideas to remove sweat | News | The Engineer

They made smaller sewer channels in the fabric where sweat runs to keep people dry.  Capillary action at its finest...

A Better Surfactant for Counteracting the Coffee Ring Effect: Marangoni vs. The Bacterium

The particles are coffee.  The edge to the right is the coffee ring.  It gets 
darker.


If you are reading this you may be drinking a cup of coffee.  Or if you are not drinking some coffee you have likely experienced this in your lifetime.  The coffee ring effect is the so named effect of how coffee or other materials move to the edge of the ring (see above video).  This effect occurs when a puddle with particles (it does not matter if they are coffee or not) evaporates leaving a characteristic ring around the perimeter.  This should be renamed to the red wine effect as it is more commonly seen after spilling wine (likely wine is more spilled because of the alcohol).  This effect is also seen with other materials like paint and adhesives.

Evaporation induces a Marangoni flow occurs inside the droplet.  If the Marangoni flow is strong can do the opposite redistributing the particles back to the centre instead of to the edges.  For the coffee ring (or red wine ring) to take place it is suggested that the Marangoni flow must be weak.  Water which composes both wine and coffee has a weak Marangoni flow.  In order to disrupt this flow surfactants can be added which lower the surface tension and stop the Marangoni flow likely leaving a even surface.  But what kinds of surfactants?

Recently researchers from KU Leuven found a bacterium that produces natural surfactants that counteracts the Marangoni flow and the spreads out the material causing the coffee ring effect more evenly.   The bacterium does this naturally...

Pseudomonas aeruginosa is a dangerous bacterium that can cause infections in open wounds. "A Pseudomonas aeruginosabacteria colony wants to find as large a breeding ground as possible. To avoid overconcentration on the edges of a wound when spreading itself during the drying-out process, the bacterium produces substances that counteract the coffee ring effect."

Interestingly the researchers took one extra step and genetically modified the bacterium so they would not produce surfactants.  The coffee ring effect was visible with these genetically modified bacterium.

Better surfactants are needed in all kinds of projects from inks, paints, adhesives to cleaning the surface of your table.  So the next time you are drinking coffee or wine and produce the a unsatisfactory visible ring think about the Marangoni effect and the bacterium that can fight it.


Making surfactant formulations from this natural surfactants from this bacterium can be made better with the only High Throughput Device, The Kibron Delta-8.    In only 12 minutes you will have an answer which Surfactant formula is better to get rid of the coffee stains.  

Multi-scale Foam Computer Simulation and Why more Scientists Should Take Bubble Baths

Foams, Foams, Foams 

People like to blow bubbles.  This starts off when you are a child and blowing bubbles with soap.  It is fun.  I once won 500 euros (700 US dollars) in travel money because of blowing bubbles to show how they are related to other membranes.  Mathematician Thomas Young (and other scientists that predate him) studied bubbles in the 18th century to show how elastic.  The surface tension and elastic properties of the bubble and the surrounding environment cause it not to pop.  With a single bubble it is easier to understand.  With clustered bubbles physicists from Berkley recently figured out how they pop and why they produce a complex bunch of physical events.  Overall this effects the overall stability of all the bubbles.  (One for all and all for one in bubble bath terms I suppose).  After one bubbles pops the other bubbles can quickly rearrange to balance the overall cluster.  A cascade like a fission bomb occurs with a number of sequential pops.  

Mathematicians and scientists have pondered about this. What they did is slow down the time and divide it into steps...Scientists like to break things down into simple solvable problems.  These scientists from Berkley  broke the lifecycle into three phases that can be mathematically modelled:

1) rearrangement - the bubble reorient themselves after a pop

2) drainage - accounts for the effect of gravity and likely the water being drained

3) rupture - the moment when the bubble pops 

They say it in this eloquent yet nerdy statement:

'Liquid drains from the bubbles' thin walls until they rupture, after which the remaining bubbles rearrange, often destabilizing other bubbles, which subsequently pop. Note the sunset reflections. The research could help in modeling industrial processes in which liquids mix or in the formation of solid foams such as those used to cushion bicycle helmets.'  

These of course could help with other foams like bubble baths....

This is a scale-separated approach where important physics is done in each of the distinct scales.  The researchers at Berkley took the expressed equations within a computer simulation and for added realism (what is this a comic book) added the way the sunset would look on the reflected bubbles.  

Many of these problems could have been solved if more scientists took bubble baths like Archemedes.  These problems could help to make better solid foams for bike helmets, the safety foam in Judge Dredd or potentially liquid foams for uhhh well better bubbles baths.

See the whole article in Science

These steps can be seen in this video:

.

What happens when you wring out a washcloth in zero-G?

What happens when you wring out a washcloth in zero-G? 

The surface tension of water was originally studied by Agnes Pockles while she did her dishes.  While now Chris Hadfield takes this physical concept that is still not totally understood to space using washing dishes as an example.  When people are frustrated that they cannot study science in a University or do not have access to the materials you might be able to take a look around and wash some dishes.  Who knows you may do what Agnes did and publish her findings in Nature.

News: Surface structure controls liquid spreading - Aalto University

News: Surface structure controls liquid spreading - Aalto University
'Like an aquaduct without walls.'

Changing the Surface Tension of Electronic Inks

For years people have wanted to make circuits using a printer like in their home on paper.  The possiblibilities in the near future to make 'rapid-prototyping circuits, integrated circuit on paper, sensors, functional RFID tags on books, even daily life personal electronics and educational training are endless. This concept is called Printed-Circuits-on-Paper (PCP).  The idea is to make new devices, faster, cheaper and potentially disposable.  Conventionally metal is deposited on a surface using a number of complex methods.    But can you make this faster and do this with a regular desktop printer?  The answer is yes!

There is a problem with doing this.  The main problem people face in this field is to get the material they are printing with to the correct surface tension.  The surface tension of the metal has to be correct in order to spray in the right size on the substrate.  Now scientists in China have made  developed a method to print flexible electronic circuits on paper using liquid metal ink.  Electronic inks are more difficult because they have an extremely large surface tension.  

How did this team from Beijing do this?  Firstly, the scientists improved the adhesion of liquid metal alloy ink by an oxidation strategy.  The team designed new print machinery to overcome the high surface tension of the ink.  Generally you would want the surface tension to be from 37-60 mN/m depending on the substrate and the properties of the ink.  This new machinery has a brush-like porous pinhead (looks a little bit like a mascara brush).  The last step involved a specially coated paper (changing the substrate) that offered this special ink to attach easier. The scientists tested a number of different papers and used AFM to compare their properties.  They mention that the whole printing process can be done at room temperature using an office printer.  This is the future!  

See original article here.

Develop Inks Easier with Kibron Delta-8.  A faster Surface Tensiometer.

Columbia engineers manipulate a buckyball by inserting a single water molecule

Columbia engineers manipulate a buckyball by inserting a single water molecule

It will help solve a surface tension problem by understanding a single water molecule and see how it interacts with hydrogen bonds.  "The important role of hydrogen bonds in the properties of water, like surface tension and viscosity, and the precise interactions between a single water molecule and hydrogen bonds, are still unclear," Chen notes, "so our new technique to isolate a single water molecule free from any hydrogen bonds provides an opportunity for answering these questions."

Blood Spatter Solving Crimes

You may have seen the last episode of CSI, Monk, The Shield, Dexter, Criminal Minds or some other crime show that I am not aware.  The technology is advanced for understanding blood splattering?  Right?  Wrong.

You can understand blood stain pattern analysis to help you recreate the scene of the crime which may interpret the origin or help with identifying the weapon.  

Several kinds of information can be found from blood stain analysis.  For example:

1. Distance from the blood source to the target
2. Direction of travel and impact angles
3. Nature of the force used to cause the bloodshed
4. The object used to cause the bloodshed
5. Sequencing of multiple bloodshed events
6.Interpretation of contact or transfer patterns

When properly documented, bloodstain patterns found at the crime scene, or on a particular person's clothing, can be used to:

What does this have to do with surface tension?  Since blood is an aqueous fluid information information would apply like viscosity and surface tension as well as gravity acting on the fluid (not in space).  Blood can spray like ink around a room and depending on the outgoing force.  Like ink from an ink jet nozzle spraying on paper a bullet passed through the body at a high enough speed can create a similar spray that can flow onto the carpet.  With both the droplet size is important.  For ink the droplet size relates to the pixelation and to get a certain size droplet a specific surface tension needs to be reached.  In the same way the droplet size of a blood stain relates to smaller and smaller droplets like an atomized spray or mist which may relate to faster and faster speeds.  The blood will not break up unless it is acted upon by a force like a bullet.  For the blood to break up the force must be great enough to overcome the surface tension of blood ( 56  mN/m).  The blood when sprayed across the carpet forms a nearly perfect circular shape due to the surface tension of the blood.  This spherical shape will be maintained until the blood droplets hit the surface of the carpet.  The blood spray would depend on the size, and speed of the bullet.    One might be able to calculate the speed and size of the bullet and likely the location of the shooter.  Bullets can reach speeds from 180-1500 m/s.    So with that range you likely would have different blood stains from an exit wound.  

Position Based Fluids Demonstration

Water is very difficult to simulate due to its surface tension and other dynamic properties.  Even for molecular dynamic simulations the air water interface is not so precise.  The video game industry is at the forefront of science and has helped drive computing to the cutting edge.  (Alan Turing would be proud!).  Games are approaching photorealism to the point that the movie the Matrix may be our new reality.  Water physics has been notoriously difficult to implement properly.   So what did people do?  They made a new algorithm.  

'A new fluid simulation algorithm (FSA) from PhysX appears to have made a breakthrough with its Position Based Fluids (PBF) technique that is based on the same Position Based Dynamics (PBD) framework used for simulating cloth and deformables in the PhysX SDK.

According to PhysX Info, PBD uses an "iterative solver" that allows it to "maintain incompressibility more efficiently than traditional SPH fluid solvers. It also has an artificial pressure term which improves particle distribution and creates nice surface tension-like effects (note the filaments in the splashes). Finally, vorticity confinement is used to allow the user to inject energy back to the fluid."

Further information on the technology is available in the following SIGGRAPH 2013 paperby Miles Macklin and Matthias Mueller-Fischer. The demonstration video (running on a single GTX 580) is available below.' via Toms Hardware.

Sounds legit.  Sound awesome.  Sounds like we are going into the Matrix.  

Surface tension gives water bubble trouble › Dr Karl's Great Moments In Science (ABC Science)

Surface tension gives water bubble trouble › Dr Karl's Great Moments In Science (ABC Science)

Pulmonary Surfactant Life Imitates Art

Although a fluorescent monolayer experiment can look like a print from Merrimekko it is actually a film showing lipids, pulmonary surfactant and nanoparticles at an interface.  

What are pulmonary surfactants?

Pulmonary surfactants are needed in our lungs to aid in breathing.  The latter is a surface-active lipoprotein complex that binds to the former to do a number of things in the lung:

• To increase pulmonary compliance or the ability for the lungs to inflate changing the volume.  The lung has a normal surface tension of 25 mN/m but at the end of expiration the pulmonary surfactant needs to decrease to near zero.  The lung surfactant takes the work away from breathing and allowing the lung to inflate easier.  This also helps to prevent the collapsing of the lung (with just lipids they might collapse on itself).

• Aveolar size regulation.  If the pulmonary surfactants are more concentrated on small alveoli it helps to keep a constant rate of both alveoli and lung expansion.  When the alveoli are increased in size the pulmonary surfactants are spread increasing the surface tension (e.g. water is more bonded and less surfactant to separate it) slowing the expansion of the alveoli.
• Keeping airways dry.
• Pulmonary surfactant gives us innate immunity.  With our lungs one of the main entry points to the body (and many people get bronchitis at least once in their life) it is important to have something to prevent infection.

What are they studying in the above picture?

Since the lungs are a main entry point to the body and drugs can be fast adsorbed (as any smoker might know) scientists are developing new ways to study the lung.  To study lung surfactants you need a Langmuir Blodgett film where you can add the lipids (mostly DPPC) and the pulmonary surfactant (like SPC).  By using something like the Kibron Microtrough scientists can add carbon nanoparticles to see how they influence the the pulmonary surfactant.  As the above picture shows a snapshot of this is captured and different patterns are observed as a simulations is made by compressing the lipid layer from a gas phase (lung expansion/inhalation) to a more solid phase (lung contraction/exhalation).  

SPIE.org : SPIE Newsroom : Folding photonic nanostructures

SPIE.org : SPIE Newsroom : Folding photonic nanostructures

Relationship between Margaret Thatcher and Surface Tension

Margaret Thatcher was chemist who graduated from Oxford before she became a lawyer and a politician.  During her Chemistry endeavors she was known to have invented Mr. Whippy soft scoop ice cream at J. Lyons and Co.

Ice cream and milk in general has interesting surface tension properties.  In general ice cream is a colloidal dispersion.  Colloidal dispersion consists of small particles of one phase (solid, liquid or gas) in another continuous phase.  The particle size may range from an order of nanometers to microns.  The surface properties of the different phases can influence the properties as a whole.  A typical ice cream is 30% ice, 50% air, 5% fat and 15 % matrix (a sugar solution) by volume.  In this colloid suspension it is an emulsion, ice crystals and foam.

The interfaces between the two immiscible liquids in ice cream create in interfacial tension which is dependant on the surface area of the droplets.  One interesting thing that early ice cream manufacturers did was shake the ice cream.  This added air and the emulsion at the top was suspended in a foam.  Margaret Thatcher, the Iron Lady, used her chemistry skills add more air to this emulsion.  This created a lighter fluffier ice cream that cost less because air costs nothing.

Surface Science in my refrigerator...soon

As a taxpayer you may think that you are wasting money on research at publicly funded Universities that you may never see in your lifetime, occasionally you are correct.  However, sometimes the research can go from lab testing to your home (or more specifically your kitchen) very quickly.

If you live in the Western world likely you have eaten ketchup.  Americans consume around 36 million tons of ketchup annually (ca 2008 chachacha).  The inventors of ketchup probably did not care too much about its fluidic properties.  The problem with ketchup is that it is a thixotropic fluid.  This means that under normal conditions it has a thick or viscous property but when the ketchup bottle is shaken or stressed it has a shear thinning property.  Many thixotropic fluids take a finite time to obtain equilibrium viscosity.  With ketchup the gel viscous state returns almost instantly.  Ketchup has another characterization calls a pseudoplastic fluid.  This is likely why designing a new kind of bottle was innovative.  

Originally, ketchup was in glass bottles and for anybody that grew up in that era it was always an interesting (and possibly slightly messy affair) to get the ketchup out.  With the advent of plastic ketchup bottles it allowed ketchup to be squeezed out.  Following this ketchup manufacturers  created bottles that can be set with the lid facing downwards so the ketchup settles at the top of the bottle.  With these bottles there is always some ketchup left these kinds of bottles and the bottles do not look so nice.

A designer and a scientist made a bottle and immediately found a purpose for ketchup.  The researchers at MIT introduced the LiquidGlide Ketchup bottle.  It has a coating that is composed of a porous solid layer that bonds to the surface of the bottle.  Another layer impregnated in this provides lubrication.  Varying the structure or materials used in the coatings, it can be tailor-made to any purpose and any level of lubrication be it for ketchup or other non-newtonian fluids.  The most interesting thing about this bottle is that some of the outer materials are edible.  In case you have a friend that wants to scratch off the surface and eat it.

'Sometimes the best inventions address persistent problems that people have kind of just given up on.'  That is why these researchers were a nominee for 2013 Design of the Year award and that they are on display at the Design Museum in London.  Yes, all for understanding some physicochemical properties ketchup and making a hydrophobic bottle.  Surface tension and viscosity have no clear correlation and in the case of ketchup flowing surface tension should be negligible.  However, in the glass bottle since it is superhydrophobic the surface tension effects on the surface of the ketchup are important in order for the MIT designed ketchup bottle to work.  

How long does it take to boil damn coffee in space?

'Where is my damn coffee?'

So if you were like me you boiled some water this morning for fix of caffeine found in a cup of coffee.  When man first boiled water for soups, pasta and later damn coffee he likely did not take care to really understand boiling.  Man just wanted some coffee but did not take the time to look into the pot.  Now that we have a little more time on our hands we can really take the time to look into the pot and see the boiling in action.

Boiling can be divided into two regimes:  1) Buoyancy dominated boiling 2) Surface tension dominated boiling.  The buoyancy dominated boiling is the one found common on Earth.  This is the one you see when boiling the water for your damn coffee.  As the water is heated and vaporizes into a bubble the bubble grows and is held on the surface by surface tension forces.  These push the bubble off the bottom of the pos so it rises out of the water.  Liquid rushes behind the bubble works its way (through convective forces) and the boiling repeats until you get water for some damn coffee.

What happens in space?  At lower gravity levels like in space the boiling behaviour is controlled more by surface tension dominated boiling.   One single bubble covers a large portion of the heater surface.  This could be a large bubble and its size is determined by the vaporization of the liquid, the smaller bubbles that feed it, condensation of vapor at the top of the bubble and lastly the surface tension of the liquid.

So the astronauts determined after several experiments that boiling water to make damn good coffee is different in space than it is on Earth.  I wonder if the coffee tastes better?

Here is the full article:
http://spacefellowship.com/news/art32961/mabe-low-gravity-answers-on-the-bubble.html

Physics of Fluid...Art and Physics

Found this nice art on io9 today.  Fantabulous...

http://io9.com/the-physics-of-fluid-revealed-in-spellbinding-color-459293246

The Daily Pennsylvanian :: Professor uses bubbles as inspiration for design

The Daily Pennsylvanian :: Professor uses bubbles as inspiration for design

Surface Tension of Electrowetting Displays

What is Electrowetting?

If you buy an e-reader from Amazon in the near future you may be using a technology where surface tension properties are important.  Amazon is thinking about buying a Samsung division called Liquavista for 100 million dollars.   Liquavista (and some other companies) use a technology for their displays called electrowetting.  This technology involves modifying the surface tension of liquids on a solid surface using a voltage.  When a voltage is applied the hydrophobic surface can be modified making the surface more wettable.  The voltage acts as a switch to make the surface more and less tense or more and less wettable when compared to the solid support.  The electrowetting effect has been defined as "the change in solid-electrolyte contact angle due to an applied potential difference between the solid and the electrolyte".  For reasons not known only a subset of materials are good for electrowetting.  Amorphous fluoropolymers are the best currently.  

How do they use this technology?

Liquavista uses this technology to make an optical switch by contracting a colored oil film electrically.  When no voltage is applied the colored oil forms a continuous film and the color is visible to the user of the display.  When a voltage is applied possibly with the touch of fingertip for touch screen displays the pixel becomes transparent.  The different pixels can then align to show a photograph or video (video is ideal because of the high switching speed and small pixel dimensions).  

Check out this video to see the speed at which it switches.

How is it different from other technology?

This technology is different than LCD (liquid crystal displays) since they use oil rather than a crystal to display color.  One added advantage of the oil displays used by Liquavista are that they require less power likely because they do not need to be continually refreshed.  Also they are in color so this is also different from E-Ink's product (that only use two tones to achieve the Kindle properties).  According to the BBC, using electrowetting technology could allow for devices to be built that run for several days before needing a charge.  So in essence it will have a battery lifetime like the Kindle but a colored picture like the current LCD diplays in the Iphone.  

How to find new materials to use in electrowetting?

Using a high throughput surface tension device (Delta-8) coupled with a high throughput catalyst could really explore finding new materials with the right properties for electrowetting.

WTF: 9 Surface Tension Trends in 2013 with video of course

This is more a review of some of the things I have talked about in this blog before.  However, with science and technology you have to reach a plateau before you start to see the technology in everybody's hands.  I have also included which instruments that might be useful in developing these new technologies.    




1. Superhydrophobic Coatings. I talked about the LiquiGlide product for use in making better ketchup bottles.  Many people are working on these superhydrobobic coatings from Ross technologies (NeverWet) spray on coatings which can allow your shoes to maintain a spotless shine.

2. Superoleophobic Glass Coatings. I have two touchscreen devices that I use which are like my little hands (as they would say in Finland).  Researchers are creating new ways to prevent people from getting all that grease on their touch devices after eating a bag of a full bag of ketchup chips.

3. Freaking Fracking.  Decreasing interfacial tension to help improve fracking techniques.  In order to get all the oil off the rocks better surfactants are needed to trap that residual oil.  This will help reduce the number of chemicals used.

Kibron Delta-8 is used by petroleum companies to improve their surfactants for this.

4. Electrowetting, uses an electric field to change the properties of a fluid (usually fluoropolymer).  This technology will be likely used in the successors to e-readers.  These are currently being developed.  

5. Graphene and Nanomaterials.  If you have been living in a box you should likely stay there.  Graphene is changing the world from making better display screens, integrated circuits and solar cells.  If you emerge from the box the world will have transformed to something extraordinary.  

Kibron DeltaPi and MTX are already used at Universities for making better graphene systems.

6. Battery design. The Energizer Bunny likely did not have any say in this.  Batteries are changing.  They are being printed on shirts even.  Surface tension can aid in making better materials and printing.

7. 3-D Printing Fused deposition modeling involves The model or part is produced by extruding small beads of thermoplastic material to form layers as the material hardens immediately after extrusion from the nozzle.  These beads or colloids need to have specific surface tension properties in order for them to flow better out of the print nozzle and build the respective material.  

Kibron EZ-Pi Plus would be a good solution to figuring out the surface tension of the outgoing fluid.

8. Improved solar power. New methods and materials are being used to design and build ultra-efficient solar panels. Superhydrophic coatings and films, for example, contribute to self-cleaning panel designs. New designs include solar shingles and local solar grids for developing countries. Companies at the cutting edge of solar power development include Semprius and SunPower.

Kibron's AquaPi and EZ-Pi Plus has helped in both for the wet leakage test and for the 

9. The development of biomaterials. The wetting behavior help to determine biocompatibility with living tissue for contact lenses, and heart devices heart devices for example. Kibron's users from the Center for Materials have created several different materials that could be used in biomaterials using the Kibron Delta-8.