Wednesday, 28 November 2012

Surface Tension and Maragoni Effect in your Scotch



This Christmas you may go back home and after a dinner you want a Scotch to warm the stomach a little in the cold.  You finish your Scotch and you look down into your glass to observe little patterns.  Did someone spike the turkey?  Probably not.  You are witnessing art from the physical world.  You are witnessing the Maragoni effect. The Maragoni effect due to the difference in surface tension between the alcohol and water. 

 Via Boing Boing explains the art in the bottom of your Scotch glass.  It is called Vanishing Spirits.  Here is a full explanation of the work.
The idea for this project occurred while putting a used Scotch glass into the dishwasher. I noted a film on the bottom of a glass and when I inspected closer, I noted these fine, lacey lines filling the bottom. What I found through some experimentation is that these patterns and images that can be seen are created with the small amount of Single-Malt Scotch left in a glass after most of it has been consumed. It only takes a very thin layer of Scotch to create; the alcohol dries and leaves the sediment in various patterns. It’s a little like snowflakes in that every time the Scotch dries, the glass yields different patterns and results. I have used different colored lights to add 'life' to the bottom of the glass, creating the illusion of landscape, terrestrial or extraterrestrial.
Interestingly, there was a recent article that was published in the Journal of Nature (I think) by Dr. Peter Yunker on the Suppression of the Coffee-Ring Effect by Shape-Dependent Capillary Interactions i.e. how are coffee rings made. I contacted him to see if he could see any obvious connection between the two liquids and the rings / patterns they create. He got back to me and unfortunately could not explain what was happening with the Scotch.



Thursday, 15 November 2012

Why is Surface Tension Needed for the Maker Movement? Part 1/2




I was in the mall and I saw Bre Pettis on the cover of Wired.  Bre is one of those types of people that I love.  They share knowledge in an interesting way for the masses.  He has likely inspired a lot of people to become engineers, scientists, entrepreneurs or have awesome hobbyists.  The cool thing about him is that from this he started Maker Bot. (See him make a copy of Stephen Colbert's head)

Maker Bot is a 3-D printing company.  They are doing what Apple did in the 1980's.  They are taking a idea formerly only done by hobbyists and they are making a finished product for the masses.  They have introduced the  MakerBot Replicator 2 Desktop 3D Printer which is like the Mac.  And the masses will eventually buy once they figure out what to do with them.  They will know too.  I suspect a huge rise in Etsy, Amazon and Ebay items being sold from these 3D printers.  People will build that irreplaceable small plastic part that broke on your dishwasher that some dish washing company will charge you huge amounts for if they even have the part available.  The 3D printer movement is upon us.



The maker movement is among us.  This movement is being touted as the next industrial revolution.  It could potentially bring all those products being produced in China back to the countries where they are actually consumed.  It will change manufacturing and possibly the jobs that we do in the future.  We might be going to a higher movement in  the future which could in fact change governments creating a Venus project landscape.  Perhaps the only limitations are 1) the ideas needed on what to create 2) the materials needed to create them.

The first could be provided with better science, art and medicine education so people could actually have the idea to make a custom built artificial arms like the one used by Luke Skywalker in Star Wars or plastic fish.  Without these types of education to help push creativity there is little point in continuing the maker movement.  We will not need customized things that interest people but rather just continue to produce mass market junk from a central location as they are now.

The second thing that is needed are the materials to create the objects.  These could be of anything from thermoplastic, chocolate, biological materials and metal.  In order to build layer upon layer these materials have to be in the right form in order to neatly build layer upon layer of your new squishy toy dinosaur or plastic fish.  The rheology, viscoscity and surface tension all need to be understood in order to have a printer cartridge that does not get stuck.  Different kinds of thermoplastics are being made all the time.  Potentially there will be even better in the future for printing faster and more robust items.


This is entirely true for the 3D printing technique fused desposition modeling (FDM) Stratasys offers this for building the material out of different kinds of plastic.  Currently, the fundamental limit is the viscosity and surface tension of the molten thermoplastic (like the material LEGO is made of ABS(Acrylonitrile butadiene styrene)).  One of the best ways to explore this limit would be to use the Kibron EZ-Pi Plus.  Then you could make a fish like in the video below out of several different materials depending on if you are in the range.





Okay now I am excited!  Now I want to go make some stuff...........NEED IDEAS!!! 

Tuesday, 13 November 2012

How to Save Yourself from an Bacterial Outbreak?





Cover everything in mucus.  Although that seems completely disgusting researchers at MIT have found that covering things with mucus will help prevent the spread of infection by breaking up biofilms.  You would think intuitively that mucous are the part of the infection as many of those people that are reading this (yes the five people) have had a cold at some point in their lives.  However, as MIT reports the mucus which are large protein chains with lots of sugar molecules the mucus doesn't grab onto foreign particles and trap them.  The bacteria is simply suspended in mucous so it can do less damage. 



The surface tension and other physicochemical properties like rheology, and viscosity may be important characteristic that traps the bacteria .  A typical surface tension of mucus in the a healthy adult may be 50 mN/m and vary by 10 mN/m in a diseased adult.  I suspect that all proteins in the mucous are not equal so potentially some people may trap bacteria in their mucous better than others.  If the surface tension of your mucous changes you might be able to detect diseases.  Secondly, understanding the surface tension of mucus will also help of better delivery of nebulized drugs.  One easy way to measure the surface tension of the your mucus is with the EZ-Pi Plus.  This device might help to pave a new treatments for cancer, lung infections and fighting the common cold.

Monday, 5 November 2012

How to detect urinary problems by peeing?



Unfortunately, this blog post is not for women or men that pee while they are sitting.  At this point I am peeing standing.  It is always amazing to watch the color, flow and protein amount (those bubbles that you see in the morning protein) in my pee.  Call it crazy call it what you will but I think it is important to know your body and what is coming out of it.  I particularly like beet root for example because it makes me look like I am peeing fire like some kind of angry dragon.  Today I stumbled on this interesting headline:

'Men should go with the flow at urinal'

In this news story covered by the  New Zealand Doctor newsroom correlates peeing flow rate and shape characteristics due to the changes in the surface tension of the pee to potentially detect some medical problems.  A computer model of liquid jets escaping different outlets (think of a rubber hose and compressing it to make ovals and other shapes) and then they compared their findings with the volunteers streams.  They could diagnose a number of urinary problems.  There is a interesting relationship between shape and flow rate when peeing 'which suggests poor meatal opening during voiding'.

"This has advantages over existing [urodynamic testing] in that it is completely non-invasive, simple and cheap to implement and avoids inaccuracies associated with voiding in a clinical setting and obtaining data from a single void," the researchers said. So what does mean for you?  Nothing if you pee sitting down.  However if you watch watch while you pee, maybe you could take a video of it and send it to the researchers.

You also do some simple tests by measuring the static and dynamic surface tension of your pee with a surface tensiometer to understand whether you have rheumatic, neurological or oncological diseases as well as other things like jaundice. 

Thursday, 1 November 2012

Row, Row, Row your Leg: The Secret behind Water Strider's Movement in Water




Water striders are an insect people describe as an animal that harnesses the physical properties of surface tension for its mobility.  You would think that after several years of studying water striders an insect no larger than a quarter you would have figured them out.  There is still a lot to learn apparently.  

Nobody really understood how they push forward to move.  People thought that capillary waves were used to move.  A MIT math major and high speed cameras helped to solve the puzzle (loving high speed cameras in science from hummingbirds to water striders they are more useful than ever before).  Hu (MIT math guy) along with his PhD supervisor John Bush found that the water striders only use the middle of their three pairs of legs to "row" across the water.  The ouring leg creates a vortice just underneath the surface that twist away from the standing legs which due to surface tension are luckily on top of the water.