Naked Science Forum
General Science => General Science => Topic started by: neilep on 31/07/2015 18:48:43
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Wocha Scientific Experts Of Wondrous Academia,
I know my ' subject' seems a bit vague but I just read this :
Virus Heat Up Water
A team at Drexel University have found a way to make water boil three times more quickly. The technique works by covering a heating element with a virus found in tobacco plants. The coating decreases the size and number of bubbles that form around the element, which in turn increases the heat transfer to the liquid
When I read this I thought that's amazing !...and then I thought how does such an experiment come into being ? What made someone think to use a virus that is found in tobacco plants ? was it arrived by deductive reasoning ? How did they discover that a virus found in a tobacco plant is great at heat transfer ? As a laysheep I am mystified by the ability of scientists to conduct experiments that to a laysheep ,like me, seem to have a tenuous structure
Whajafink ?
can someone explain to me a possible thought process that led to that experiment ? Would there have been a precedent for an experiment/study like that ?
many Thanks
hugs and shmishes
mwah mwah !!
neil
As a sheep the wool is easily pulled over my eyes !
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When I read this I thought that's amazing !...and then I thought how does such an experiment come into being ? What made someone think to use a virus that is found in tobacco plants ? was it arrived by deductive reasoning ? How did they discover that a virus found in a tobacco plant is great at heat transfer ?
You'd really have to ask those particular scientists this question. I can only take a guess. Someone learned about the virus. They then studied the virus. As a result of the study they learned it's properties. The scientists might then come up with an application for it merely during a bit of day dreaming and thus an idea is born. That's how it works for me sometimes.
I'll share something important about studying a problem that paid off in the long run.
When I first came to the internet and started discussing physics someone claimed that the mass of an object does not depend on the object's speed. However in special relativity there's a concept known as relativistic mass which is simply referred to as mass. However if you were to read a text on particle physics or many texts on special relativity then you'd also find that people use the term "mass" to refer to what's known as "proper mass" aka "rest mass." That's the relativistic mass of a slowly moving object. But they claimed that nobody uses relativistic mass anymore. And they meant that quite literally and the claimed that their arguments for their choice of terminology is better than the alternate choice. So I decided to study this problem in all its detail. I made it the thing that I was going to be the most knowledgeable about in the world.
There's also something called "invariant mass" which is basically the same thing as proper mass but it can be applied to a system of non-interacting particles. Its defined as the magnitude of the object's 4-momentum and has the value m in E2 - (pc)2 = (mc2)2
I was very cautious about this. I saw no a priori reason to assume that the properties of mass defined like that has the same properties of a single particle with the same value. It turned out that I was justified in my caution. If a system of particles has pressure and that pressure contributes to the inertia of a system of particles. That's not accounted for in invariant mass.
I knew that they were merely talking about
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This story is covered here: http://www.theguardian.com/science/2015/mar/26/new-discovery-uses-virus-to-boil-water-three-times-faster (other news outlets are available)
It appears that the researchers were looking for ways to improve heat transfer in industrial boilers, and part of that optimization is to maximize the contact area between the hot surface and the coolant (usually water).
This is a major problem in nuclear reactors, because when the fuel element exceeds about 200C (at atmospheric pressure), the water forms a wall of steam between the fuel element and the coolant, reducing heat transfer, which causes the temperature to climb even higher, forming a vicious cycle which could result in the fuel rod buckling, or even causing the fuel pellets to melt.
This effect may be experienced in your own kitchen as the Leidenfrost phenomenon (https://en.wikipedia.org/wiki/Leidenfrost_effect), when a droplet of water splashes onto a hot frypan.
One way to increase surface area is to use a nanostructured surface. These have been used for years in battery electrodes, gas masks, industrial catalysts, electrolytic capacitors (and now supercapacitors), and in non-reflective coatings for structural elements in cameras and telescopes. There are many techniques for producing such structured surfaces, such as etching the surface, sintering a fine powder, and recently, growing carbon nanotubes.
These scientists probably tried a number of techniques to roughen the surface before they came across the Tobacco Mosaic virus; viruses are nanoscale organic parasites with very uniform characteristics. This virus had previously been tested as a nanoscale template for a battery electrode (https://en.wikipedia.org/wiki/Tobacco_mosaic_virus#Investigational_uses), so application to a heat transfer problem is a natural progession.
The Tobacco Mosaic Virus has a long history in research - it was the first infectious disease proven to be non-bacterial (in 1892), it was the first use of the word "virus", and Rosalind Franklin (of DNA fame) worked on the structure of the virus. There is a lot of experience growing it in the laboratory.
Apparently, the researchers had to tweak the genetics of the virus so that it would clump together on a surface to form the right ratio of volume to surface area (the goal being the highest possible surface area in a thin sheet with maximum connectivity). And they had to nickel-plate it to give the necessary thermal conductivity.
So now you have a laboratory demonstration of more efficient boiling; the race will be on to scale up this process to industrial scale, but also to find other ways to produce a nanostructured surface with even higher thermal conductivity. (Tobacco Mosaic virus has very poor thermal conductivity and is not a good substrate for nickel plating; carbon fibers would have better thermal and electrical conductivity as a core, but they are hard to produce, not very uniform in length and their properties vary greatly). Maybe neilep could sacrifice some wool, in the interests of science?
Other applications will also be investigated - cooling semiconductor chips was mentioned.
Or, you could just be cynical, and think that the tobacco industry is faced with a shrinking market for inhaled tobacco products, and so they are looking for innovative ways to redeploy the large numbers of farmers and specialized agricultural machinery which was built up to meet the demand for this drug....
So maybe instead of spraying the tobacco fields with insecticide, we should just spray them with Tobacco Mosaic Virus, as feedstock for industrial manufacture of more efficient heating elements in residential electric kettles?