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Are CRTs as bad for landfills as they're made out to be?
My Username replied to My Username's topic in Applied Chemistry
TV’s are bad for landfills, but are we imagining something worse than reality? People view crystal drinking glasses as an expensive luxury, even though they are imbedded with 21% to 41% lead oxide. CRT's, for those who don’t know, are the big tubes in televisions and computer monitors. They most typically contain less lead oxide than the crystal glasses people put their lips on. There are excessive and restrictive laws about what has less lead toxicity, but selling drinking glasses which contain significant amounts of lead is something the government won't touch? Either way, the lead is imbedded in the glass. It's stuck, and can't hurt anything, so it's not harmful. Only if the glass breaks is it harmful, but the "harm" is quite minimal since only a tiny portion of lead escapes from the extremely small surface area of the broken portion of glass. Furthermore, there are many people who would be happy to dispose of their CRT tv’s. And for somebody who has not spent much time looking into the subject, may find themselves thinking that the government is there to help them and be on their side. But the government offers an extremely few solutions, and does more to inform people of the punishments that could be dished out by not fully obeying the rules; rules that are so excessive that it is at times IMPOSSIBLE to obey the law. But most people are passive, submissive, and are stuck with minds that have, over the years, been shaped to conform to the government without asking questions. Our generation did not produce nor except the toxic and irreversible earth poison that had been created and mass produced over 70 to 90 years ago. The capitalists and engineers filled up their bank accounts and portfolios, and created that toxic conundrum, and the politicians stuffed their wallets while they let it happen. Eventually our generations inherited that pattern and way of life. We got their political propaganda machine, and the toxic mess along with it. The politicians entrusted to do what is best for us simply benefited at the expense of future generations. People in multiple different roles, like the worst of criminals, seem not to have had a concern for their actions which has now left our future in worse shape. Now, the problems lay at the feet of our generations. While the greedy create many similar situations for future generations to suffer through, I think that at least in regard to this issue, we should consider ourselves fortunate. Ideally there would be zero pollution, but there is a realistic and positive way to view this situation. It’s rather simple. The less we break the disposable televisions, the less lead we eventually become exposed to. Televisions in landfills may crack or be damaged enough that in your opinion it is broken. But since it will never be anything near as destroyed as to resemble grains of dirt, the fragments of glass are surprisingly large. And more importantly, they still contain the vast majority of the lead people are so fearful of. Fear is valuable at times, and a few cracks in some glass is something that can waste fear and distract you from living a better life. --Jay Lakota -
Are CRTs as bad for landfills as they're made out to be?
My Username replied to My Username's topic in Applied Chemistry
The melting temperature of lead is over 600°F. And glass melts at a much much higher temp than that. But landfill temperatures are roughly between 100 and 200°F. They rarely even get near 200. It's not common for a landfill to get to 200, and if it does and/or goes over, it's not by hundreds of degrees. If, for example, it were to go so high as to get to the mid 400's, most of the garbage would smolder, and the government would easily know that it's well above regulation temperature. There are chemicals that can melt the glass, which would allow the lead to leech into the ground. But the chemicals are expensive and I'm assuming quite rare to a landfill. Of course, people dump chemicals in landfills even though they aren't allowed to. But with all the regular garbage that is thrown out, a rare instance where someone illegally dumps a bucket of a chemical capable of melting glass would not melt a whole lot of televisions. Imagine a bucket of water spilling. It might get a few things very close by wet, and might seep down and do the same for some stuff under, but that's a few square feet maybe, in an area that is acres large. However, even though I think lead becoming free from the glass by an uncommon chemical would be incredibly rare, the dilemma could be eliminated by having CRT-only dumps or sections of landfill. I remember when dumps would except car/truck tires. They kept them separate, in a tire only pile. Not that it was good for the environment, since the tires slowly leeched into the ground. But it has been done where certain areas are designated to one specific type of item. A television-only pile would not get hot or leech anything, and to make it safe from vandals or accidental fire, they could be buried under dirt like other garbage is. The reason that I believe people and the government don't want CRTs in landfills is simply because they don't know much about the subject, and lead sounds scary. There is another possible reason, and it's that there is some information that I am unaware of. Maybe somebody could explain what I'm missing or getting wrong that would make sense of the rule against CRTs being dumped. -
First, I'm not suggesting it's ok to dump more into landfills. I thought of the idea and question simply because it didn't make sense to me. People would say something like a television contains 5 or 8 pounds of lead, and if it's put in a landfill it destroys the environment. Of course, some lead does. Second, for the purpose of this post, I'm ignoring the existence of phosphor in the CRTs. Of course a television tube, monitor, or whatever CRT it is, contains a lot of lead. and lead is very bad for the environment, but the lead in CRTs is embedded in the glass. It's not just coated on the inside surface or something more easy to remove. If I'm wrong, please explain so that I can understand. But it seems to me that the glass would need to be crushed into very small particles for any significant amount of lead to escape. Even a trash compactor wouldn't come close to crushing the glass into such tiny sand-like particles. A CRT that might crack open, or may become broken into a dozen shards wouldn't release much lead relative to total lead content. There is still a relatively low surface area. It's not like a lead atom can (usually) jump across a dozen glass molecules. So am I wrong and missing something, or would a relatively very small amount of lead actually escape from a TV buried in the ground? (Assuming we don't give it a million years to turn into microdust.)
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How does this pump work without moving parts?
My Username replied to My Username's topic in Engineering
Oh, I didn't see the post by Strange. Maybe posted while I was writing my response. Thank you, I believe that explains it. -
How does this pump work without moving parts?
My Username replied to My Username's topic in Engineering
Thank you for responding. I'm glad I have a name for it now. Is the whole system called the siphon, or just that one T looking part? I don't understand how the vacuum is created in it though. In a "regular" siphon (is it called a gravity siphon??) liquid in part of the hose is being pulled by gravity, creating a vacuum behind it. But in this one the water is being pushed out with water pressure from the water source. Is the water's momentum causing it to pass through the "T" and continuing to the other side, rather than the water splitting ways and some water flowing out through the barrel? If that is what's happening, then is the friction between the moving water and coolant inside the T causing some coolant to flow with the water, and creating a low pressure spot behind it to continue this same cycle? I don't know if that's right or not, but it's the only explanation I've been able to make sense of so far. -
I have a question about how something works. I work in a shop that uses coolant. The coolant comes in a barrel, and it's mostly just oil. It needs to be combined with a lot of water before being used for the machines. To get the mixed coolant, we just turn the water valve on, point a hose, and mixed coolant comes out. What I don't understand is how the "pump" works. It's just one small plastic part with no moving parts and no energy source other than the water line. I drew a crappy picture to help explain how the setup looks. A copper water pipe (orange), with a shut off valve, connects to one side of a plastic piece that looks like a T (black). The other side of the T connects to a hose (green) that we use to aim the coolant into containers. At the bottom of the T there is another hose (yellow) which goes into the barrel (blue) of unmixed coolant. To get mixed coolant, all you have to do is turn the water valve on. But I can't quite figure out what is happening here.
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I was thinking about this, and couldn't think of the answer. Two objects far away from each other accelerate toward each other in space because gravity attracts them to each other. They come together to form one object. When the two objects were far apart, their combined energy was less than the newly formed object has. Where did that energy come from?
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I recently replaced a wheel bearing assembly on my car. The bearings and race were steel, and they were seated in the aluminum steering knuckle. Removing the bearing assembly required a sledge hammer and a lot of time and effort. Why does that happen? I'm asking here because after an hour of searching on the internet I could only find things about it that were practical, such as putting a graphite paste between the two metals next time. But I couldn't find an explanation of what happens on the molecular level to cause the bond.