...well, we've had reactors since the '50s and so far there haven't been any significant "problems" with (civilian) waste in the US. Sure, it's in ponds. So? There it sits, decaying nicely. Were it somewhere else, it would decay at the same rate. Plus, the reactor site is already secured, so there's not much proliferation threat. Spent fuel takes up very little volume, and its activity decreases exponentially. When the ponds fill up, the older (less active) waste is put in dry casks. Sooner or later, the government will get the lawsuits untangled and build the permenant site to put these. The current system may be a "temporary" solution, but when "temporary" means 5+ decades, it's hard to see it as a make-or-break problem...
Follow-up: good (but highly technical) info on why this works is available here. Basically, the fuel is constructed so that as it gets hotter, it gets less reactive.
I'm a chemical engineering senior at the UofWisconsin Madison. Two years ago I took a nuclear reactor lab class here at the UW where we learned about and operated the college's reactor (1 megawatt thermal -- lots of good info at this site). It was one of our lab exercises to rapidly remove the control blades (flat plates in this reactor -- not rods) all the way to create a pulse. A *pulse*. That is, even with the blades removed, the reactor would not melt down. (can see it at this site) Since the rxr was water-moderated, there is no conceivable mode of operation which would allow the core to melt. In fact, it's so safe that it was built right in the middle of campus. And this was designed back in the day...
Actually, as I recall the neutron capture cross-section of deuterium is only about 1/1000 that of standard hydrogen. So you'd still be much worse off using heavy water if your goal was shielding. Some reactors use heavy water to make them *more* efficient (i.e., keep the n-flux up in the core while using less fuel to reach criticality and still providing moderation/cooling simulatneously).
The pressure equation of state is true generally (if you make the ideal gas assumptions), whether the system is adiabatic, isothermal, isobaric, any particular set of (physically realistic) conditions you wish to choose. It is true that in the atmosphere there are some non-intuitive trends, but that's because it takes a *whole lot more* than a simple equation of state to model something as complex as the atmosphere. Heat transfer must be take into account: convection, conduction and radiation. Of course, an equation of state would be useful (and valid) also, but it's just not the whole story...
Well, that's kinda deceptive really, because pressure and temperature are very related for a gas. If you model the gas as idea, then you get the relationship:
P*v=R*T (where v=V/N) or, if you'd rather use density...
density (rho) = P*M/(R*T)
So, you can have temperature in terms of pressure, or pressure in terms of temperature. They are interrelated: with a gas, you can't change one of those parameters in isolation.
Hah -- very true, although I hadn't thought of that much before. It is meaningless (outside of certain fluid flow problems, anyway). At least I haven't come across anyone trying to apply Mach numbers to spacecraft yet. Now *that* would be funny.
Also irrelevant. In the US, federal laws trump state ones. Check the constitution, Article VI:
"This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding."
Does anyone actually care where the guy who invented (insert technology item here) was when he invented it? Maybe some people do, but I doubt their numbers are very large.
Well, it's only natural that with a new ability come new questions. In general though, most of those questions go away, or at least seem a lot less mysterious, with just a little look at what's going on.
When I was conceived, there was initially a single celled zygote with my DNA in it. That egg cell then developed into me. If a clone were to be conceived, then that clone would start out as a single celled zygote with DNA, just as I did. Now, it's true, that in the case of a clone that DNA would be shared with it's progenitor.
But ask yourself this: If two identical twins are born, are they the same person? Of course not. They share exactly the same DNA, but they are certainly two different people. A clone would have *exactly* this same relationship with it's progenitor. They would share the same DNA, but they would be unique individuals with different experiences and different lives.
A clone is not a photocopy -- it is just a alternate way of arriving at a fertalized egg, and it is no less natural than many other medical treatments that are performed every day.
Trying to ban cloning because it forces various questions to be asked in religious circles is exactly the same as what happened in astronomy centuries ago. It is better to answer any such questions now than to divide society into factions and battle away to the detriment of all.
It's all a matter of symantics. You could very well call it cloning. You could just as well call natural twins "clones". Personally, I've cloned a weeping willow tree that grows near our home -- I broke off a stick from a neighbor's tree and planted it near the lake. The stick grew roots and now there are two willow trees with identical genes (although one of them is still quite small, relative to it's "parent"). I'd call that cloning.
First off, fraternal twins wouldn't rightly be considered "clones," as they do not share the same genetic material. Second, and more importantly, dolly is an imperfect clone for a very specific reason. Dolly was created by a technique called nuclear transfer. In this technique, the nucleus of a fertalized zygote (essentially a stem cell) is removed and replaced by a donor nucleus. In the case of dolly, that nucleus was a differentiated cell (from breast tissue). While the differentiation process is not yet well understood, it is highly likely that this is the source of the problem. Normal identical twins are produced by the splitting of stem cells, so this does not affect them. If you would like to learn about the process (usually a recommended step before forming an opinion), do a google search on "telomeres" or visit:
http://www.synapses.co.uk/science/clone.html
And in general, invoking a diety is rarely the best way to explain a mystery. Jumping to "magic" should be a last resort -- not a first step.
Human cloning occurs now, and always has occurred. Ever seen identical twins? That's a better job of cloning than any lab could ever do, because an artificial clone would always be off-set in age, relative to it's progenitor. Identical twins, on the other hand, come out at the same time.
A microprocessor cannot make any real contribution to global warming. Suppose that a chip dissipated 50 watts of heat (I have no idea what they actually produce/consume, but this seems about reasonable). For comparison, the sun delivers about 1370 W/m^2. Over the projected area of the entire planet (about 40 million square meters). In other words, 1 processor at 50 watts adds 0.00000009% to the earth's energy balance. Pretty tiny, even when you consider large numbers of chips. Global warming is more the result of greenhouse gasses that prevent this heat from being dissipated into space, as (essentially all of) it naturally is. The problem with earth's environment, much like the problem with computer chips, isn't in how much heat you produce/receive, it's in how efficiently you get rid of that heat.
BTW -- I didn't check my math too carefully, so be warned...
Hmm... Wonder if there are any congressmen listed on ebay. I don't exactly have $187k lying around, but maybe there are some budget congressmen available... They could certainly come in handy.
Slashdot Mirror
...well, we've had reactors since the '50s and so far there haven't been any significant "problems" with (civilian) waste in the US. Sure, it's in ponds. So? There it sits, decaying nicely. Were it somewhere else, it would decay at the same rate. Plus, the reactor site is already secured, so there's not much proliferation threat. Spent fuel takes up very little volume, and its activity decreases exponentially. When the ponds fill up, the older (less active) waste is put in dry casks. Sooner or later, the government will get the lawsuits untangled and build the permenant site to put these. The current system may be a "temporary" solution, but when "temporary" means 5+ decades, it's hard to see it as a make-or-break problem...
Follow-up: good (but highly technical) info on why this works is available here. Basically, the fuel is constructed so that as it gets hotter, it gets less reactive.
I'm a chemical engineering senior at the UofWisconsin Madison. Two years ago I took a nuclear reactor lab class here at the UW where we learned about and operated the college's reactor (1 megawatt thermal -- lots of good info at this site). It was one of our lab exercises to rapidly remove the control blades (flat plates in this reactor -- not rods) all the way to create a pulse. A *pulse*. That is, even with the blades removed, the reactor would not melt down. (can see it at this site) Since the rxr was water-moderated, there is no conceivable mode of operation which would allow the core to melt. In fact, it's so safe that it was built right in the middle of campus. And this was designed back in the day...
Actually, as I recall the neutron capture cross-section of deuterium is only about 1/1000 that of standard hydrogen. So you'd still be much worse off using heavy water if your goal was shielding. Some reactors use heavy water to make them *more* efficient (i.e., keep the n-flux up in the core while using less fuel to reach criticality and still providing moderation/cooling simulatneously).
The pressure equation of state is true generally (if you make the ideal gas assumptions), whether the system is adiabatic, isothermal, isobaric, any particular set of (physically realistic) conditions you wish to choose. It is true that in the atmosphere there are some non-intuitive trends, but that's because it takes a *whole lot more* than a simple equation of state to model something as complex as the atmosphere. Heat transfer must be take into account: convection, conduction and radiation. Of course, an equation of state would be useful (and valid) also, but it's just not the whole story...
...um, yea, that's what I was implying. Read the parent.
Well, that's kinda deceptive really, because pressure and temperature are very related for a gas. If you model the gas as idea, then you get the relationship:
P*v=R*T (where v=V/N) or, if you'd rather use density...
density (rho) = P*M/(R*T)
So, you can have temperature in terms of pressure, or pressure in terms of temperature. They are interrelated: with a gas, you can't change one of those parameters in isolation.
Hah -- very true, although I hadn't thought of that much before. It is meaningless (outside of certain fluid flow problems, anyway). At least I haven't come across anyone trying to apply Mach numbers to spacecraft yet. Now *that* would be funny.
Now predator and prey robots that could also self-replicate, that would be a cool experiment...
Also irrelevant. In the US, federal laws trump state ones. Check the constitution, Article VI:
"This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding."
Does anyone actually care where the guy who invented (insert technology item here) was when he invented it? Maybe some people do, but I doubt their numbers are very large.
Well, it's only natural that with a new ability come new questions. In general though, most of those questions go away, or at least seem a lot less mysterious, with just a little look at what's going on.
When I was conceived, there was initially a single celled zygote with my DNA in it. That egg cell then developed into me. If a clone were to be conceived, then that clone would start out as a single celled zygote with DNA, just as I did. Now, it's true, that in the case of a clone that DNA would be shared with it's progenitor.
But ask yourself this: If two identical twins are born, are they the same person? Of course not. They share exactly the same DNA, but they are certainly two different people. A clone would have *exactly* this same relationship with it's progenitor. They would share the same DNA, but they would be unique individuals with different experiences and different lives.
A clone is not a photocopy -- it is just a alternate way of arriving at a fertalized egg, and it is no less natural than many other medical treatments that are performed every day.
Trying to ban cloning because it forces various questions to be asked in religious circles is exactly the same as what happened in astronomy centuries ago. It is better to answer any such questions now than to divide society into factions and battle away to the detriment of all.
It's all a matter of symantics. You could very well call it cloning. You could just as well call natural twins "clones". Personally, I've cloned a weeping willow tree that grows near our home -- I broke off a stick from a neighbor's tree and planted it near the lake. The stick grew roots and now there are two willow trees with identical genes (although one of them is still quite small, relative to it's "parent"). I'd call that cloning.
First off, fraternal twins wouldn't rightly be considered "clones," as they do not share the same genetic material. Second, and more importantly, dolly is an imperfect clone for a very specific reason. Dolly was created by a technique called nuclear transfer. In this technique, the nucleus of a fertalized zygote (essentially a stem cell) is removed and replaced by a donor nucleus. In the case of dolly, that nucleus was a differentiated cell (from breast tissue). While the differentiation process is not yet well understood, it is highly likely that this is the source of the problem. Normal identical twins are produced by the splitting of stem cells, so this does not affect them. If you would like to learn about the process (usually a recommended step before forming an opinion), do a google search on "telomeres" or visit:
http://www.synapses.co.uk/science/clone.html
And in general, invoking a diety is rarely the best way to explain a mystery. Jumping to "magic" should be a last resort -- not a first step.
Human cloning occurs now, and always has occurred. Ever seen identical twins? That's a better job of cloning than any lab could ever do, because an artificial clone would always be off-set in age, relative to it's progenitor. Identical twins, on the other hand, come out at the same time.
A microprocessor cannot make any real contribution to global warming. Suppose that a chip dissipated 50 watts of heat (I have no idea what they actually produce/consume, but this seems about reasonable). For comparison, the sun delivers about 1370 W/m^2. Over the projected area of the entire planet (about 40 million square meters). In other words, 1 processor at 50 watts adds 0.00000009% to the earth's energy balance. Pretty tiny, even when you consider large numbers of chips. Global warming is more the result of greenhouse gasses that prevent this heat from being dissipated into space, as (essentially all of) it naturally is. The problem with earth's environment, much like the problem with computer chips, isn't in how much heat you produce/receive, it's in how efficiently you get rid of that heat.
BTW -- I didn't check my math too carefully, so be warned...
Hmm... Wonder if there are any congressmen listed on ebay. I don't exactly have $187k lying around, but maybe there are some budget congressmen available... They could certainly come in handy.