Post by William McCormick on Jun 25, 2012 19:10:38 GMT -5
When you mix epoxies that create plastics or rubber, you usually start with well known quantities. And things usually go according to plan.
For those that have mixed larger batches and had the batch just harden right up on you. Or smoke or catch fire. You experienced a very fascinating phenomena of the universe.
A spheres surface area compared to its volume, changes in a skewed ratio. As you increase the size of a sphere, the surface area of the sphere, becomes smaller in ratio to the volume of the sphere. It is this reason that cells like the amoeba cannot get any larger then they are. There is no way for them to pass food into the cell and waste out of the cell, in quantity to support any larger cell.
It is a fascinating limitation that can be seen everywhere. If you run some numbers through the two formulas for a sphere you will see the ratio that develops when comparing a small and large sphere.
The two formulas are:
Pi D^2 for the surface area,
or Pi (3.14) Times Diameter Squared (Diameter ^2)
Pi D^3 ÷ 6 For the volume of a sphere,
or Pi(3.14) x Diameter Cubed (Diameter^3) ÷ 6
When you are mixing chemicals that react with heat as a by product. You have to be careful, that you do not mix too large a batch of material, that the small surface area compared to its large volume cannot dissipate.
Here on the Island where I live, just such a thing happened at a chemical company. They mixed a large batch of a rubber like epoxy, and it caught on fire, when the reaction went out of control.
The smoke from a small 100 gallon tank, covered the area in smoke. The cloud was actually reported in Connecticut. Yet of all the 100 gallons of material that was reacting, only about five gallons of the material actually burned.
There was so much smoke that local firefighters could not even find the building where the reaction was taking place.
That is why you rarely see tires stacked up like you would years ago in junk yards. It is a severe hazard to the community.
This volume to surface area of a sphere is very interesting in other areas of our lives. Most cancer cells are larger then human cells. That is why it is possible to kill them by injecting levels of poison that only human cells can expel and survive.
Many years ago cancer was treated with radio equipment that could instantly heat the entire human body. In doing so the cancer cells, were found to have literally drowned in their own excrement. It is a touchy subject though, today. Cancer has become quite a business.
Some of you may be thinking that a cube actually at first grows in surface area, as you make a cube bigger and bigger. So there should be no problem.
The problem is that the product in your cube shaped tank, can still overheat, in a spherical shape within the cube shaped tank.
Sincerely,
William McCormick
For those that have mixed larger batches and had the batch just harden right up on you. Or smoke or catch fire. You experienced a very fascinating phenomena of the universe.
A spheres surface area compared to its volume, changes in a skewed ratio. As you increase the size of a sphere, the surface area of the sphere, becomes smaller in ratio to the volume of the sphere. It is this reason that cells like the amoeba cannot get any larger then they are. There is no way for them to pass food into the cell and waste out of the cell, in quantity to support any larger cell.
It is a fascinating limitation that can be seen everywhere. If you run some numbers through the two formulas for a sphere you will see the ratio that develops when comparing a small and large sphere.
The two formulas are:
Pi D^2 for the surface area,
or Pi (3.14) Times Diameter Squared (Diameter ^2)
Pi D^3 ÷ 6 For the volume of a sphere,
or Pi(3.14) x Diameter Cubed (Diameter^3) ÷ 6
When you are mixing chemicals that react with heat as a by product. You have to be careful, that you do not mix too large a batch of material, that the small surface area compared to its large volume cannot dissipate.
Here on the Island where I live, just such a thing happened at a chemical company. They mixed a large batch of a rubber like epoxy, and it caught on fire, when the reaction went out of control.
The smoke from a small 100 gallon tank, covered the area in smoke. The cloud was actually reported in Connecticut. Yet of all the 100 gallons of material that was reacting, only about five gallons of the material actually burned.
There was so much smoke that local firefighters could not even find the building where the reaction was taking place.
That is why you rarely see tires stacked up like you would years ago in junk yards. It is a severe hazard to the community.
This volume to surface area of a sphere is very interesting in other areas of our lives. Most cancer cells are larger then human cells. That is why it is possible to kill them by injecting levels of poison that only human cells can expel and survive.
Many years ago cancer was treated with radio equipment that could instantly heat the entire human body. In doing so the cancer cells, were found to have literally drowned in their own excrement. It is a touchy subject though, today. Cancer has become quite a business.
Some of you may be thinking that a cube actually at first grows in surface area, as you make a cube bigger and bigger. So there should be no problem.
The problem is that the product in your cube shaped tank, can still overheat, in a spherical shape within the cube shaped tank.
Sincerely,
William McCormick
