Sunday, 30 October 2011

How is NASA is Turning Urine into Water?

Subtitle: Filtering Pee for Hydration.  From Water World to Today's Space Shuttles

I am a huge science fiction fan.  Everything from Neuromancer, The Time Machine, Hitch hiker's guide to the Galaxy to closer to real stuff like Michael Crichton's NeXt.  I love it enough that I have even tried to pen a couple of short stories myself.  (Let's see how that turns out).

The thing I love about science fiction though is not just fantastic fantasy in the out of this world stories,  but also  the fact that they can predict a future.  On the website technovelgy you can see some of the technology that people have created in the early 20th century to inventions that occur only today.  Things like touch screen tablet computers (first seen in 2001 Space Odyssey) to filtering pee for drinking water.  Before you say, 'Ohhh disgusting!' you have to understand why Kevin Costner aka the Mariner filtered his own pee and why people on the Atlantis the space shuttle are doing it.  Easy answer!  It is efficient, cost effective and prefiltered though your kidneys'.

In Water World the Mariner (half-man, half-fish) lives on earth after the polar ice caps have melted.  On his raft he had a device that filters out his pee.  You might think: why not drink the water around you?  However, it might be easier to filter out the small number of contaminants in urine than filter out the large number of variable contaminants in ocean water.  But the rudimentary technology from Waterworld is here!  Today astronauts filter their pee on the space shuttle Atlantis because it saves both money and space.  To get a four litre jug of water on a space flight it costs 80,000 dollars and the current urine recycler on board uses a lot of energy.  So as the title suggests golden showers can really be a metaphor for real gold in the context of saving money.  The new osmosis system they are developing uses passive filtration (no energy).  The filtered water that the astronauts will drink soon is be cleaner than U.S. tap water.  

In the astronauts and possibly the Mariner's case it is important to delve into the properties of urine.  What are they? Urine consists of 95% water, with the remaining constituents are mainly salt solutions.  These are in order of decreasing concentration urea 9.3 g/L, chloride 1.87 g/L, sodium 1.17 g/L, potassium 0.750 g/L, creatinine 0.670 g/L and other dissolved ions, inorganic and organic compounds (e.g. bile salts and surfactants).   Urine is sterile until it reaches the urethra where gram negative bacteria from outside can go into the pee (which makes it stink).  The physicochemical characteristics: pH 7 (can vary 4.6-8), density of 1.003–1.035 (g·cm−3) and surface tension 55.7 to 62.0 mN/m; mean for group 58.7 mN/m (from 12 people after 24 hours). One interesting note in this paper is that bile salts cause most of the change in the surface tension with the other salts, urea and creatine causing little change to the water surface tension.  This information might help to produce a better filtration system.

Currently, two researchers are conducting this technology assessment: Kennedy Space Center researcher Howard Levine and  Dynamac researcher Michael Roberts to create a forward osmosis bag (FOB).  Basically it works like this: wastewater (e.g. pee) fills the bag and passively transfers through an inner layer, which contains the sugar solution; toxins are left behind as the liquid passes from the outer layer to the inner and the wastewater becomes safe to drink. However, the system has not been perfected yet, and certain toxins can still get through the filters (these might be bile salts since bile acids are potentially toxic to cells).  If the astronauts drink these toxins they can build up in the kidneys over time making the FOB only practical for short journeys.  Editors note:  to fix the problem they might want to use some Carafate (sucralfate), and Questran (cholestyramine) or some other bile acid sequesterants.

Think I am lying?  Check out this demonstration:

By the way HTI the company that makes a similar filtering system has used this technology for rescue missions on earth from Haiti to Hurricane Katrina.  The results are amazing.  See this video.

Monday, 24 October 2011

Surface Tension Videos For Kids

When I was a kid I think I asked, 'Why?' a million times.  'Why do stars shine?', 'Why are the birds flying like that?', 'Why does the water do that?' until my parents gave me Owl Magazine but still asked enough questions to take me to do a PhD.  Still I am asking the question, 'Why?'   Many times children ask great questions that adults either do not know the answer or just do not know enough about the subject to give a good question.  Also teachers sometimes underestimate the aptitude of children thinking they may not be able to grasp a subject.  Children are usually smarter.

To communicate surface tension better to children and stop them from asking  '#%&%& why?' all the time here are some sites:

I posted this before. 

However, no kid wants to sit through a lecture (most adults cannot). 

So here is a simple experiment that would be easy to reproduce in any classroom anywhere in the world. 

You need:

1. a paper clip
2. a paper towel
3. a glass of water
4. soap

Watch the video to see how to do this experiment.

There are probably a lot more experiments that you can do.  The concept is more important than the experiments.  I think a lot of teachers in elementary school focus too much on the experiments being cool and fun but not enough actual explaining properly the concept in a fun way.
To further explain this you will have to understand what a hydrogen bond is. The hydrogen bond  in water is necessary for life to exist.  A simple way to show this if you get 12 kids to stand up and grab hands.  If one is oxygen and the other two are hydrogen they make one water molecule.  So you have a total of four water molecules.  Each water molecule can bond with four two other water molecules.  This is hydrogen bonding of pure water.  The hydrogen bonds are strong and able to stop a force coming at them.   Next you add a soap to this mixture.  Get a couple of other kids to move between the four water molecules spacing them out.  So you have water - soap- water- soap.-water- soap- water.  If you have a force e.g. like a paper clip moving towards this unbonded surface water then on the surface will not support the force.

Saturday, 22 October 2011

Hydrophobins the Magic Inside Mushrooms

In Finland mushroom picking is a big thing.  You go into the forest with a paper bag and search for different kinds of mushrooms.  In Finland this is a popular past time and a highly guarded secret so people will not discover your hidden mushroom treasure in the forest.  Many of these mushrooms that you can find in Finland can be in the range of 25 euros a kilo.  So if you are picking or shrooming as they like to call it and you come out of the forest you have to be prepared if someone asks you, 'where did you find all those mushrooms?'  a common answer is 'I got lost in the forest and I cannot remember,' or 'I was just walking my dog and found these.' When you get home you can fry them up and put them in an assortment of dishes like wild mushroom risotto.

I have a jar of dried mushrooms right now in my kitchen cupboard.  I just learned that they have some interesting biochemistry in the cap of the mushroom. The mushrooms that I found in the forest is the fruiting body of a fungus.  On the mushroom cap a protein exists called hydrophobin.  These proteins contain surface active properties allowing the producer fungi to attach support structures, create air gaps through air-water interfaces, grow hydrophobic parts.and keep the mushroom dry.

 The really cool thing is how they can change the surface of materials by forming a film on the surface of a material modifying the interfacial energy of the interface.  The films can be measured using a langmuir microtrough with a tensiometer and a potentiometer.  On hydrophilic surfaces hydrophobins assemble their hydrophobic side to the solvent, and vice versa.   So if water interacts with glass normally it will run off like a film or disintigrate into smaller droplets and if water interacts with teflon (a hydrophobic surface) it will cause a lotus effect.  When you add hydrophobins to each of these the glass will be hydrophobic beading the water making a lotus effect and the teflon will turn hydrophilic.

What can you use these?  I think the full extent has not been found.  One thing is they can modify the surface of textiles to make kind of a biomolecular goretex on textiles that maybe do not look like goretex. (1) Possibly someone can make a spray out of this.   Nanoscale drugs have been made using hydrophobins to coat poorly soluble molecules and drastically increase  their solubility. (2)

BASF is the first company with the capability to manufacture hydrophobin on an industrial scale. They have some great videos (here).  Hydrophobins are studied by a VTT researcher named Markus Linder.

1. Klaus Opwis & Jochen S. Gutman (2011), Surface
modification of textile materials with hydrophobins. Textile
Research Journal 1594-1602
2. Hanna K. Valo et al (2010), Multifunctional Hydrophobin:
Toward Functional Coatings for Drug Nanoparticles. ACS
Nano 1750-1758

Saturday, 15 October 2011

Got Milk?

I woke up this morning and had some coffee.  I make coffee with a press so with the right amount and time the coffee can be quite good.  My girlfriend usually adds milk to her coffee.  If I am in the mood I will add some however mostly I prefer it unpolluted.  Around the expiration date she might sniff it then drink a little before adding it to the coffee.  A couple of times after drinking she could taste that the milk was a bit off.  Also she mentioned at different times of year the milk quality changes for the same brand of milk.  So I was wondering whether you could measure surface tension of the milk to get a quick estimate of the quality.  Is this possible?

Yes.  Milk has  a lot of different surface active proteins and fats making a colloid in water.  The surface tension of pure cows milk depending on the cow, the season and other factors could be around 52 dynes/cm.  However, if the milk sits for a while and certain these proteins break down after a phase seperation of the colloid suspension the milk will decrease in surface tension to 35 dynes/cm.  Milk is an important source of protein for much of the world's population.  By understanding the properties of milk and preventing the separation and subsequent change in the milk from good to rancid the milk could be distributed better.  Also it one might learn which cow is better at producing milk and optimize the conditions for those cows..... Just some ideas what surface tension might allow you to do.

Hell, I don't even drink milk. I just like these splash photography pictures.

Thursday, 13 October 2011

5 things in Tears

The full title of this post is '5 things in tears that you had no idea because you were too busy crying like a little bitch'.  That seemed too long so I truncated it.  You can have three types of tears (basal tears -normally needed to wet the eye, reflex tears (ones needed from a foreign particles like dust or onion vapour) and psychic tears like you are doing right now.  

1. Water.  The essential liquid for life.  Water has a surface tension of 72.8 dynes allowing it to stay together in a droplet that comes off from your face after you listen to some emo band like 'My Chemical Romance' or 'Him'.  With all the other things in tears the surface tension can be lowered to 43 dynes/cm.

2. Mineral salt.  So you are crying and you taste your tears.  Salty right?  The human tears and sweat glands are evolutionary related leading some people to believe they are similar to other animal's salt gland.  Which is a gland in the tongue in animals like sharks and birds to excrete excess salt (and also why you do not see most animals crying).  If crying is good to get rid of any excess salts in your body I have no idea.  However, the tears are high in potassium which supports that theory that they may be evolutionary related to the salt.  The tears will have a similar content in sodium and potassium and even urea to the blood.

3. Antimicrobial peptides and proteins like antimicrobial peptides defensins and LL-37 work to bind and cover the bacterial membrane to create pores thus destroying it.  Phospholipase A2 is also found here that (and in snake poison) to destroy the phospholipid membrane of any foreign particles with particular phospholipids to and help to cause a inflammation reaction for more.  Phospholipase A2 is the principal bactericide for staphylococci and other gram-positive bacteria in human tears.  The activivity of this enzyme is awesome and really cool pictures can be acquired using fluorescence coupled with a monolayer device to make a small film.

4. Lysozyme is secreted in many places.  Lysozyme binds to the cell wall of the bacteria and cleaves the sugar in the cell wall destroying the gram negative bacteria. 

5. If you are under stress you might protein-based hormones, prolactin, adrenocorticotropic hormone, and leucine enkephalin (natural painkiller). These types of tears would vary greatly then if they were produced by something from  all of which are produced by our body when under stress. Some of these hormones can have The change in sex drive could be attributed to the drop in testosterone provoked by the chemicals in the tears meant to reduce aggression and may cause a crying woman to lower the sex drive in a man. In the animal world, it has been found that some blind mole rats would rub tears all over their bodies as a strategy to keep aggressive mole rats away.  So basically emo kids are probably preventing bullies from beating them up but they are also lowering their overall attractiveness.

Sunday, 9 October 2011

FYFD is an awesome Tumblr Blog!

This blog is very esoteric but tries to relate surface tension and how to measure it to everyday life.  The interesting thing about surface tension is that there are a lot of interesting news stories as well as science and art projects that people are doing that makes it fun to blog about.  However, I never really saw anybody else blogging about similar things until today.

I saw this really cool site called  Fuck Yeah Fluid Dynamics.  I read about this site on Pulse (the best place to get news) via I09 via Physics of Fluids.  Check it out....  It has a lot of really cool videos and some explanations.  If you like understanding fluid properties, surface tension it ect. you will fall in love with this site.  I will repost the best ones or ones that relate to this blog.