do a search on gradient antireflective films. This was done in the 1980s and used extensively for very high energy laser optics by several labs. By either reacting glass surfaces, or by coating the surfaces with nanoparticles, one can readily produce surfaces with essentially no reflectance (0.01%) over the entire visible spectrum. What is produced is a porosity gradient whose index varies from 1.0 at the surface to that of the bulk material. Since there is no clear interface, reflectance is broadband. At one government lab, meter-sized optics were treated. I remember that one visiting congressman ran into one of the windows because it was, functionally, invisible. These technologies never saw broad acceptance because porous surfaces react with the environment, and reflectance increases (requires periodic cleaning).
Sigh, it seems that scholarship is dead...
The "stacking bits on end" is done via two paths. First, head designs are being modified so that the magnetic fields are more vertically oriented. One of the buzzwords that will emerge is TMR for Tunneling Magneto-Resistive. The current dominant head design is GMR, or Giant Magneto-Resistive. For more details, do a Google search for both. The smaller the lateral width of the bit footprint, the higher the bit density.
The other pathway to vertical recording is to change the shape of the crystals in the magnetic medium. As bit size decreases, it occupies only a few small primary crystals. If the crystals are made smaller, more uniform, and more vertically oriented, the bit footprint can be further reduced without compormising storage life. Relaxation of the magnetic field due to thermal noise, etc. is actually a much bigger problem, especially as the bit becomes distributed over fewer and fewer grains. Some of the current solutions to overcome stability problems involve stabilizing layers (e.g., Magic Dust).
In any event, all the manufacturers are doing is to follow the HDD equivalent of Moore's law, which has held well since the 70s. Built it and it will get filled!
Take a look at the following US Patents: 6537635 and 6511728. My best guess is that their first gen disc uses the Silver/Aluminum redox effect. This is dead easy to block, and, moreover, is reversible. This stuff could be a lot of fun to play with. (p.s., the full text of the patents is available on the US PTO database- use any search engine to get the URL)
how old do sheep normally live
on
Goodbye, Dolly
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I may be the only actual sheep farmer to reply on this thread! This whole thing is totally silly for two basic reasons. (1) This type of pneumonia is relatively common. The average age of a working ewe is ~8 years. I have seen a number of sheep die from this condition at 6 years or less over the past few years. If you told me that any other 6 year old ewe died, it wouldn't be notable. (2) There is zero statistical basis to make any conclusions. What's the distribution of mortality in sheep, or even in Scottish sheep of this particular variety. The sample size required to say whether or not the event is statistically meaningful is quite large. This is thetype of stupid pseudo-science that I've come to despise. Logic, anyone?
I live and farm in a heavily Amish community here. One of the biggest reasons that the Vector tobacco was so readily accepted was that they guarantee a high price at harvest. For the last 30 or so years tobacco has been a high return cash crop. Many Amish families have used the added income to pay the excessively high taxes resulting from the intense development pressure. A couple of years ago, tobacco prices collapsed due to the general anti-tobacco sentiment, and a shift of the big firms to non-US sources. Local farmers have been hard=pressed to find an equally profitable (legal) alternative, and many young people were considering leaving the farms due to the lack of any profitable path forward (milk and grain prices are at 30 year lows). Two years ago, Vector stepped in and offered free plants and a guaranteed price that was 3-5X higher than the remaining buyers. It didn't take long for acceptance.
Tobacco is a very labor-intensive crop. The Amish are probably the last group left in the US that can raise it and process it in the traditional manner (i.e, no chemicals and no machine processing). However, it is hot brutal work (I helped cut a field of Vector last July when it was 102 in the shade). They do it because of the economics, not the ethics. You might keep their situation in mind as you buy your food at the supermarket...
Obsidian is a volcanic glass that is basically SiO2 with included carbon. SiO2 is a great glass former, so when a silica rich eruption occurs, much of the outflow is quenched, forming obsidian. It takes quite a bit of time to crystallize to quartz
As a glass scientist, I wanted to add my 2 cents worth. Almost any substance can occur in a glassy state if quenched fast enough. This includes most metals, plastics, and pitch. Below a critical temperature (the glass transition temperature Tg) a glass is a brittle, perfectly Newtonian solid. At temperatures above Tg, viscosity decreases to the point where relaxation can occur, and the substance becomes rubbery, then fluid. The apparent viscosity at Tg is ~ 10^13 poise. Real motion is observed at ~10^8 poise. The Tg of optical pitch is a bit below room temperature, and the room temperature viscosity is ~10^9 poise. The problem with the experiment cited is that temperature fluctuations change the viscosity exponentially. Droplet formation time will vary accordingly.
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do a search on gradient antireflective films. This was done in the 1980s and used extensively for very high energy laser optics by several labs. By either reacting glass surfaces, or by coating the surfaces with nanoparticles, one can readily produce surfaces with essentially no reflectance (0.01%) over the entire visible spectrum. What is produced is a porosity gradient whose index varies from 1.0 at the surface to that of the bulk material. Since there is no clear interface, reflectance is broadband. At one government lab, meter-sized optics were treated. I remember that one visiting congressman ran into one of the windows because it was, functionally, invisible. These technologies never saw broad acceptance because porous surfaces react with the environment, and reflectance increases (requires periodic cleaning). Sigh, it seems that scholarship is dead...
The "stacking bits on end" is done via two paths. First, head designs are being modified so that the magnetic fields are more vertically oriented. One of the buzzwords that will emerge is TMR for Tunneling Magneto-Resistive. The current dominant head design is GMR, or Giant Magneto-Resistive. For more details, do a Google search for both. The smaller the lateral width of the bit footprint, the higher the bit density. The other pathway to vertical recording is to change the shape of the crystals in the magnetic medium. As bit size decreases, it occupies only a few small primary crystals. If the crystals are made smaller, more uniform, and more vertically oriented, the bit footprint can be further reduced without compormising storage life. Relaxation of the magnetic field due to thermal noise, etc. is actually a much bigger problem, especially as the bit becomes distributed over fewer and fewer grains. Some of the current solutions to overcome stability problems involve stabilizing layers (e.g., Magic Dust). In any event, all the manufacturers are doing is to follow the HDD equivalent of Moore's law, which has held well since the 70s. Built it and it will get filled!
Take a look at the following US Patents: 6537635 and 6511728. My best guess is that their first gen disc uses the Silver/Aluminum redox effect. This is dead easy to block, and, moreover, is reversible. This stuff could be a lot of fun to play with. (p.s., the full text of the patents is available on the US PTO database- use any search engine to get the URL)
I may be the only actual sheep farmer to reply on this thread! This whole thing is totally silly for two basic reasons. (1) This type of pneumonia is relatively common. The average age of a working ewe is ~8 years. I have seen a number of sheep die from this condition at 6 years or less over the past few years. If you told me that any other 6 year old ewe died, it wouldn't be notable. (2) There is zero statistical basis to make any conclusions. What's the distribution of mortality in sheep, or even in Scottish sheep of this particular variety. The sample size required to say whether or not the event is statistically meaningful is quite large. This is thetype of stupid pseudo-science that I've come to despise. Logic, anyone?
I live and farm in a heavily Amish community here. One of the biggest reasons that the Vector tobacco was so readily accepted was that they guarantee a high price at harvest. For the last 30 or so years tobacco has been a high return cash crop. Many Amish families have used the added income to pay the excessively high taxes resulting from the intense development pressure. A couple of years ago, tobacco prices collapsed due to the general anti-tobacco sentiment, and a shift of the big firms to non-US sources. Local farmers have been hard=pressed to find an equally profitable (legal) alternative, and many young people were considering leaving the farms due to the lack of any profitable path forward (milk and grain prices are at 30 year lows). Two years ago, Vector stepped in and offered free plants and a guaranteed price that was 3-5X higher than the remaining buyers. It didn't take long for acceptance. Tobacco is a very labor-intensive crop. The Amish are probably the last group left in the US that can raise it and process it in the traditional manner (i.e, no chemicals and no machine processing). However, it is hot brutal work (I helped cut a field of Vector last July when it was 102 in the shade). They do it because of the economics, not the ethics. You might keep their situation in mind as you buy your food at the supermarket...
Obsidian is a volcanic glass that is basically SiO2 with included carbon. SiO2 is a great glass former, so when a silica rich eruption occurs, much of the outflow is quenched, forming obsidian. It takes quite a bit of time to crystallize to quartz
As a glass scientist, I wanted to add my 2 cents worth. Almost any substance can occur in a glassy state if quenched fast enough. This includes most metals, plastics, and pitch. Below a critical temperature (the glass transition temperature Tg) a glass is a brittle, perfectly Newtonian solid. At temperatures above Tg, viscosity decreases to the point where relaxation can occur, and the substance becomes rubbery, then fluid. The apparent viscosity at Tg is ~ 10^13 poise. Real motion is observed at ~10^8 poise. The Tg of optical pitch is a bit below room temperature, and the room temperature viscosity is ~10^9 poise. The problem with the experiment cited is that temperature fluctuations change the viscosity exponentially. Droplet formation time will vary accordingly.