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OldChemE

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Everything posted by OldChemE

  1. Firechicken18--- don't forget to count atoms and charge. The number of atoms of each element have to be the same on both sides of the equation (unless, of course, you are converting matter to energy or vice versa which we don;t much do in chemical reactions). Notice how Amphibole has made sure the number of atoms on each side of each element are the same.
  2. Wish I had thought to say that. Good point
  3. At the risk of maybe offending someone (for which I will apologize in advance), comparing Philosphy and science seems to me to be almost (but not quite) like comparing Barbers and Doctors.Many years ago I attended some sort of seminar (can't remember the details) where the speaker commented on the origins of medicine. He commented on the practice of bleeding people to remove evil elements, which was done by barbers. He then pointed out that from this simple practice eventually we developed medicine and the profession of Doctors, whereas the barbers were still just cutting hair. I do agree that Philosphy is more advanced than that, but still believe the comparison has merit.
  4. Its primarily a timing thing. In a fast reactor, the fuel used readily fissions with high energy neutrons ("fast" neutrons). This is a very fast process. In a thermal reactor, the fissile material is chosen that fissions best with lower energy neutrons ("Slow" neutrons). The moderator (water or graphite) is used to slow the neutrons down to where they will cause fission. The slowdown process creates a time lag in the chain reaction which aids control. In addition, most thermal reactors that use a water moderator are designed so that the expansion of the water moderator as it heats reduces the water density just enough to become less effective at slowing the neutrons. This gives the reactor a negative temperature coefficient-- that is, excessive energy production acts to reduce energy production. The overall effect is that thermal reactors react less quickly to power excursions-- which is a control benefit. Fast reactors, by comparison, do not need a moderator and respond much more quickly to reactivity changes. Its really a trade-off. Thermal reactors are easier (less costly) to build and operate but don't do well at breeding, while fast reactors breed much better but have greater challenges in technology and materials.
  5. I've been out of this aspect of the field for way over a decade, so this is pretty general. Thermal reactors are set up such that the immediately released (Fast) neutrons from fission are themselves not sufficient to maintain the chain reaction-- the neutrons released in a slower time frame are necessary. This makes them somewhat forgiving from a control standpoint. Fast reactors do not have this somewhat forgiving time lag in the chain reaction-- making them less popular from a design standpoint. And-- they use coolants, such as liquid sodium, that are a lot more difficult to work with than water or graphite. The combination of control complexity and materials difficulties made the fast reactors less popular. Technology has been changing so I may be out of date. Back in the 60's and 70's the US (Via Admiral Rickover's organization) actually built and successfully operated a thermal breeder reactor at the Shippingport power plant which converted Thorium into usable nuclear fuel. But, as I recall, the breeding ration was very slim (something like 1.05). The advantage was that thorium is very plentiful, but it was never pursued because fast breeders (on paper at least) had much better conversion ratios. For an interesting perspective on fast reactors you should search for a very old science fiction story called "Blowups Happen" written, I think, by Robert Heinlein. It described an accident at a fast reactor, predicated on the assumption that, if you don't design for the slow (thermal) neutrons to maintain criticality, things can get out of control very fast.
  6. the operative word in the OP is "again" I don't think this is nearly the issue many others see it as. Shutting down the government has become a standard strategy for both the current dominant political parties. It too shall pass. Although I have no evidence, I suspect that the main reason why the congressional budgeting and funding process has remained structured the way it is is because both parties Like having this ability for political grandstanding.
  7. Interesting question. If, as I understand the current state of brain science, all consciousness and memories are the result of connection between brain cells, it would seem that there is nothing that could be passed on to another brain. That is, to pass anything along it would be necessary to structure the new brain to be identical to the old brain (at least as regards individual cells, connections and presumably other details). Assuming that the person you want to pass the information to already has a structured brain, there is nothing you could pass on without restructuring them (as in erasing a hard drive and copying new data-- but in terms of brain cells and links, not files).
  8. I agree with the issue of Oil Company responsibility where they have discouraged alternative fuel development-- But I still think NY and others are crazy to launch a lawsuit. They fail to recognize that a huge majority of vehicles currently in service need fossil fuels. For the oil companies to continue to supply that demand they will simply raise prices to cover what they lose in the lawsuit. They will be able to do this because, with our current transportation infrastructure, we cannot afford to regulate them out of business.
  9. Answers (in question order) are b, a, True, False, False scores (in order ) were 2, 1, 0, 4, 3 Good puzzle-- easy if you set up the possible permutations on a spreadsheet-- but fun.
  10. Conceptually it seems workable to me. The drawback is that, if I recall correctly, Ethanol provides about 60% as much energy per gallon as regular gasoline, so this solution would increase carbon dioxide buildup in the atmosphere for the same power delivered to the vehicles. Seems like this is going in the wrong direction. I'm not sure of the numbers here, but that's what I would look into.
  11. missing number is 12 (the rule is that the absolute value of the difference between the first and second number, multiplied by the smaller of the two, equals the third), |15-6| x 6 = 54, |12-10| x 10 = 20, |8-12| x 8 = 32.
  12. Find some decaf that you really like and switch to it, and keep the same hours you used to. I had to do that 30 years ago due to a caffeine allergy that developed in my early 40's. I had headaches for about two weeks, then was OK. Now-- a nice cup of hot coffee (decaf) seems to be just as good a wake-up as caffeine was before.
  13. I don't like the choices. But.... if a choice had to be made I would go with #2. Choices 1 and 3 are very risky. What if the Alien idea of curing global warming turned earth into an ice-ball? And # 3???? Think of what curing all disease would do to average life expectancy and global overcrowding. Disease can be very bad-- but it is nevertheless an essential element of the balance of nature.
  14. You don't have to get rid of the Electoral College to have popular vote decide the election. Every state has the right to divide its electoral votes any way they wish-- a couple (NH and maybe Maine-- I'm not certain) already divide their electoral votes based on their state's popular vote. The real issue, I believe, is that the Electoral College system gives States a small degree of leverage in national elections, which they would not have if the Electoral College was abolished. For example, with the Electoral College all the votes from New York and California went to Clinton, even though both states has significant votes for Trump. In this election, of course, Clinton would have won if the election was by popular vote, but that kind of situation doesn't happen very often. So, in order to switch to popular vote, the politicians in the big states would have to be willing to risk the loss of leverage. I doubt that's going to happen anytime soon.
  15. Love has so many elements (chemical, emotional, etc) that I think it is indeed possible to love more than one person at a time. The tough part is to commit to one person.
  16. I agree with Mathematic. But, if you don't use a matrix use substitution. Solve the top equation for x as a function of y (assuming the variables are labeled x, y and z), the bottom for z as a function of y, then put those two results in the center equation and you will have only one variable (y). The numbers look like they will be messy, but it would work.
  17. If your calculator is giving you an error, check settings. Most good calculators can do angles in degrees or radians. If you have it in the wrong mode (radians when you want degrees, or vice versa) it will make results come out wrong.
  18. Folks This has been a fun discussion. There are a number of threads in different forums (sp?) on the internet where this is debated. But, I think we've beat the subject to my satisfaction, I'll bow out here (not agreeing, but agreeing to disagree)
  19. While it is a theoretical nit (perhaps), it should be noted that the infinite sum of 9/10 + 9/100 .... does not actually reach 1, it converges toward 1. 9/10 is 9 tenths of the distance on the number line from 0 to 1 9/100 is nine tents of the distance on the number line from 9/10 to 1 Every term in the infinite sum adds to the sum 9/10 of the remaining distance on the number line between its previous term and the total of 1. Because bo term ever adds more than 9/10 of the remaining distance on the number line, we never actually reach 1. This is the situation of the old puzzle about a person who in each unit of time walks exactly half the remaining distance to his/her destination. With each succeeding term we add to the infinite sum we travel 9 tenths of the remaining distance to 1. Again-- it is a Limit, not an equality.
  20. Let us assume the hypothesis that 0.99.... = 1 Then, by the rules of mathematics, 1-0.99.... = 0, which is a definable number in mathematics. Or, to say it differently, a defined result proper to mathematics. if we subtract 0.9 from 1.0, the result is 0.1, which is 1/10, which is 1/(10)^1 if we subtract 0.99 from 1.00 the result is 0.01, which is 1/(10)^2 Generalizing, 1 - 0.99..... = 1/(10)^Infinity But the result of division by an infinite number is undefinable in mathematics. Therefore, 1 - 0.9999...... produces an undefined result This falsifies the assumption that there is a definable result of zero This falsifies the original hypothesis.
  21. The point is that when you talk about an infinite string of numbers you get into the topic of limits. The Limit of 0.999... as the number of digits goes to infinity is indeed 1, but 0.999... itself is not 1. Limits and integers are not the same thing. Try subtracting 0.99999..... from 1.0000..... There will be an infinitely small non-zero result. That result approaches zero as the number of digits increases, but is never actually zero.
  22. The fallacy in 10x-x = 9x is that truly infinite numbers do not behave properly in mathematics. In order to use mathematics for this you have to truncate the number someplace. When you do that, and multiply a finite version of 0.999... by 10, then try to subtract the original 0.999..., you have a result a tiny bit smaller than 9 because the first digit is 8 and the last is 1. for example: lets use 0.999999999999999. 10 x = 9.99999999999999 (14 digits to the right of the decimal). The original number, 0.999999999999999, has 15 digits to the right of the decimal. When you do the subtraction, the result is 8.999999999999991, which is not 9. In order to make the result be 9, you have to suppose that the "infinite" number you multiply by 10 has one more digit than the "infinite" number that you subtract from it. Two infinite numbers with a different number of digits is, of course, ridiculous, but mathematics will not work without that condition. You have to be very careful drawing conclusions in math using numbers that allegedly have an infinite number of digits. This is related to the prohibition against dividing by zero-- it's just another property of infinite numbers that math can't handle properly.
  23. Well, yes---I should have said something like "very limited control over the environment"
  24. In reading the OP carefully, I think it raises the important point that, while science has advanced dramatically, the human ability to accept it and not depend on other non-scientific things (such as religion) has not. I have thought on this subject a lot in the past. My conclusion is that a significant portion of humanity is uncomfortable with events beyond their control and feel a need for someone or something to be in control. This leads some to believe in religion because they would rather believe that events are part of 'God's Plan' rather than beyond control, others to believe in magic, conspiracies, "they are doing this" (whoever "they" are), etc. Unfortunately, I suspect this is inherent in the structure of the human brain and the way in which it evolved. We need to keep in mind that for probably 99% + of the timeline of humanity humans have not had science and have not had control over their environment.
  25. depends on the tires, which you did not specify. The actual diameter of the tire on a 26" bike depends on the profile of the tire-- which can vary.
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