Most elements with atomic mass less than or equal to that of uranium have at least one "stable" isotope, and an element's nuclear characteristics doesn't influence its chemical reactivity. I think TFA was talking about stability vs. reactivity on a chemical level.
Plus, how many women with a family could seriously commit 80 hours of work a week? You'd have to be crazy and obsessed about your job in order to sacrifice that much of a personal life. If that's what it often takes to achieve greatness, I'm surprised there are any professors, male or female, willing to take on the commitment.
Unless you're talking about having to provide breastfeeding for a newborn, there is little difference between the amount of time and energy a woman or a man "could" commit to work or any other activity, provided they had the necessary drive. Committing 80 hours a week to work by anyone demands a significant sacrifice on the part of both folks in a marriage, and if both people don't agree on why that commitment is being made, then it's going to cause big problems. By the way, 80 hours a week for at least couple of years is par for the course, if you're one of the principals doing a startup. Research isn't the only thing that requires obsession.
If it could be applied densely enough (maybe if you had a very densely finned heatsink with the material deposited onto all the fin surfaces), and if the material itself had sufficient power density capability. I'm assuming it's converting IR photons into electrical energy by stimulating a potential difference somehow - I'm not a theoretical physicist. Maybe it's like a reverse laser? This would be different from a thermocouple because from what I can tell it's not based on junctions between two different metals, and it's not based on having a hot junction and a separate cold junction.
There are few countries of any size that are homogeneous, and I'm sure that India falls into that category as well. I'm originally from the Netherlands, and I've lived in Ontario, Alberta, and California. In the Netherlands, people from the northeastern part of the country (not even counting the Frisians) have a very different speaking dialect compared to the central part, and the southern part of the country also has different word pronounciation in some cases. You can easily tell if a person grew up in Amsterdam or Rotterdam just by hearing them speak - and those cities are less than an hour's drive apart. The dialect is only part of the local culture. Different parts of the country generally have different primary industries, different standards of living, more of a rural vs. urban outlook on things.
In Canada, there are also differences in culture, slang, and societal norms as you go from the Atlantic provinces to the densely (as in "lots of", not "thick-headed";) ) populated regions of Ontario and southwest Quebec, to the prairies and the Pacific. People from Ontario are regarded with some initial mistrust in Alberta, while folks from Alberta are regarded as redneck simpletons in Toronto. The US has just as many regional characteristics, and it's only natural that people from Canada will trigger a "you're not from around here, are you?" response from a lot of US citizens, and vice versa.
Most of the time it's not an unwelcoming thing - people are just curious. The few cases where people take a stand against people from different parts of the country or the world are almost always due to the government trying to help, and instead raising fears among the locals that something is getting taken away from them to the advantage of others. In Canada, the various provinces contribute or get "equalization payments" that are regulated by the federal government, and one of the things that does is to give the perception (if not the actuality) that the have-not provinces are being subsidized to maintain an above-practical level of population and industry at the expense of the other provinces.
Computers are in many ways complementary to humans, not comparable. A video card is part of an image output system, while our eyes are an image input system. Similarly, the keyboard and mouse don't replace or replicate the functions of our hands - they are what we use with our hands.
The memory structure and processing paradigm in most computers is also quite different from what we know of the human thought process. The computer uses binary logic to carry out its operations, while the brain, as far as we know, uses a complex system of neural-net interaction. NN simulations have shown learning and recognition ability that is similar to that of humans, but since it is not easy to mimic, program, or teach the interaction of billions of neurons, large neural nets are not commonplace.
Anthropomorphizing (?) the memory systems of a computer as "short term" and "long term" and associating that with RAM and hard drives is fallacious. The RAM will retain information for as long as the power is applied, which can be just as long or longer than the magnetic media on the hard drive will retain its state. If you remove power from a human (don't try this at home... ) you'll lose both short and long term memory pretty much simultaneously.
It has already been remarked that project funding typically goes to the lowest-cost bidder, and everyone else is locked out for the remainder of the project. Then when the low-cost method hits major delays and overruns, and it turns out that the other methods that never made it off the proposal drawings were actually more likely to succeed, there is already too much money down the drain on the bad implementation to abandon it.
When the developers are forced to spend money like it's their own, rather than the government's, it is more likely that groups will shoot for little incremental successes rather than trying radically new technologies all in one go. SpaceShipOne's success was not due to it adopting a (sorry) pie-in-the-sky approach - it just brought some well established technologies together in an optimal way. Similarly, Armadillo's work toward VTOL rockets with real throttleable engines is breaking ground and putting pieces in place for future space industry development.
Private development gets done because the business owners believe that their stuff will eventually be able to meet the industry requirements. The government's current method of allocating project funds seems too biased toward technology development and not enough towards results.
In WW2, the British and to some extent the Americans put a huge dent in the German advance by having a very good understanding of the psyche of their opponents and of their command structure. Both sides had radar as far back as 1940, but the British used it much more effectively and designed a defense system around it that optimally combined what little resources they could bring to the situation at that time. The various deceptions that were devised by the British went largely undetected by the Germans, and while their impact is difficult to measure in lives saved, there is little doubt that various decoys and false transmissions in the right places allowed the Allies to attack more effectively at a low cost in extra manpower. The point is that defeating your opponent is as much (or more) a mind game as it is a matter of brute strength. Robots, even with remote control, aren't going to have the agility or cunning required to survive on the battlefield.
Up here in Canada the cars are marketed through Mercedes as well. It's not especially clear to me why DaimlerChrysler wouldn't brand it at least as a Chrysler/Dodge model... Chrysler has been importing vehicles and rebranding them as their own (Mitsubishi, etc) for decades.
There's quite a bit going on both in the academic world and by prosthetics manufacturers. One of the bigger struggles is getting an amputee a prosthetic that's suitable for what they're going to be doing - a foot optimized for running looks a lot different from a foot that's designed to look like a foot and that you'd wear with ordinary footwear. Without turning this into a shill for our products, the company I work for makes an inertial-sensor based activity monitor that helps doctors choose an appropriate prosthetic depending on the patient's activity profile. This is one of our customers
The guy who designed the SR-71's engines ended up winning one of the most prestigious aviation prizes (no, I can't remember which) for the way that the movable engine inlets ended up being responsible for something like 80% of the thrust produced at high speeds. He later became director of the Lockheed Skunkworks in the era where they produced the F117A.
OK then... How about if the British (or anyone else with the required steel foundry infrastructure) resurrected the Tallboy or Grand Slam bombs used in WW2? Put a few of these into space in orbits that give decent time-to-target, and all you have to do is de-orbit them at the right time. If you can drop them from low earth orbit, then you don't even need any explosive. A ten-ton half-molten ingot dropping on a concrete bunker at several times the speed of sound has got to hurt.
On 80x86 platforms, ints were 16 bits. Even now, if you use a tool such as Borland to compile PC apps, and the code generation is set to 80386 (which is the default), you may still get 16 bit ints - I don't remember, and if I really need to worry about it I use 'short' or 'long' as the case may be. On the M68K, it depended more on which toolset you used, since the register set inherently was 32 bits wide. IIRC Sun compilers gave 32 bit ints by default, while Diab and some others gave 16 bit ints.
Well, this is what Wikipedia has to say about it. In short, yes, for historical reasons. Occasionally we (here at work) will use 'order of magnitude' in a specific context where it means a factor of two, but that's by no means common usage.
...it will only take one mistake (and it's not that unusual) to fry someone's $500mil baby.
Not likely. If you assume that the jamming approach is to beam noise at the satellite in the frequency range it's designed to accept, then the power required to jam its receiver compared to what is required to damage the thing is at least a couple of orders of magnitude (factors of 10) different. Jamming the satellite's transmissions in a certain terrestrial location simply involves having localized noise generators in the same frequency band as the satellite in question. Or, for world-wide coverage, just launch a satellite(s) in a compatible orbit to the target satellite, and broadcast away.
Thanks... 'howstuffworks' is a good name - it explains HOW things work but not WHY. The reason you can use a turbine on the exhaust gases and thereby extract the 20 to 30 horsepower required to drive the compressor (assuming a 200 or so HP engine) is because the exhaust is hot and it's under pressure. The gas leaving the turbine is cooler and at lower pressure than the gas entering the turbine - it's lost both heat and pressure on its trip through the turbine, and that energy has gone into producing torque on the shaft driving the compressor.
Take several engineering courses on thermodynamics and properties of materials, design and build your own turbosystem, and then drive it without problems for a couple of years. When we're on even ground you can explain to me again how turbos work.
Based on doing a LOT of dyno testing and a couple thousand laps of track time at the local road course, I would suggest that unless you have a large crew and the budget to build multiple versions of things that you want to test with, keeping it to 'one factor at a time' is by far the fastest way to get results. At the track, a one percent improvement in lap speed is pretty significant, but there are many factors that can make more than one percent difference in engine power or available traction, and then any improvement you're looking for will be lost in the noise, skewed by incidental factors, or they'll be so correlated that you can't tell what caused what. Even if you're testing on the dyno, which eliminates driver errors, nobody will ever suggest that you should go do a set of runs where you're changing the timing and the mixture at the same time. At least part of the reason for that is that engine tuning is not a linear problem - just because the engine likes 38 degrees BTDC on a lean mixture doesn't mean that it will work best at 38 degrees when you have the mixture right.
The other think about multiple factor testing is that it can take serious time to prepare multiple items to test. For example, if you're trying to adjust sway bars, then ideally you'd have a range of bars ready at the track and you could swap them out and do tests. The problem with that is that a lot of practice time at tracks is limited to 15 or 20 minute sessions, and it's hard to do multiple bar swaps in that time.
About a decade and a half ago a group of us were heavily involved in club racing at the local road course. There were many onlookers with no end of advice on how our cars weren't as suitable for racing as their (whatever), and that if they came out they'd keep up no problem. From time to time one of the onlookers would actually put in the time and effort to race-prep their cars, and then they'd find out that there was a reason why we spent a lot of evenings and weekends doing fabrication and dyno tests. Going fast is hard, and figuring out what works takes time and money.
When you tune your engine to go fast, you do it by improving the engine's volumetric efficiency. That typically means you'll burn more fuel (and air) than the original engine, but also make correspondingly increased power from a given engine displacement. If you combine that with gearing appropriate to your driving environment, you WILL get decent mileage, and be able to merge into traffic too.
If you want to significantly increase your mileage, then you need to address waste heat, and you need to reduce the car's inertia.
A turbocharger uses exhaust heat energy to drive an intake air compressor, and thereby recovers some of the 25 percent or more of the fuel's BTU content that goes straight out of the tailpipe. Typically the turbo configuration is sized towards the performance end of the spectrum, but if you pick a more street oriented compressor, you will improve the cruising efficiency compared to a naturally aspirated engine as well as having some serious power at your disposal when you put your foot in it. If you want to just increase your mileage, then drop the engine displacement when you install the turbo - your cruising mileage will be governed more-or-less by the engine size and configuration (number of cylinders, inline or vee, etc), and the peak power is determined by how much boost you run.
The acceleration you can get from your car depends a lot on the rotational inertia of the various driveline parts. A lighter wheel/tire combination will reduce the rotating inertia so that you can spin everything up to speed more quickly. A lighter flywheel and clutch also contribute significantly to faster acceleration. Faster acceleration means you burn less gas while getting up to speed, so you will get better mileage especially around town. Reducing the weight of your car's body and interior will generally improve acceleration as well, but it also decreases the comfort level, so you'll be making a choice there between fast or cozy.
I'm not sure how different the two specs are, but if (for instance) DX9 and OpenGL 1.3/1.5/2.0 had different word-lengths defined for color precision, then you could advantageously design the hardware to support those word lengths natively. Implementing OpenGL word-lengths in hardware and not DX9 would simplify the required drivers and speed up operation for OpenGL over DX9. If, of course, there is a difference.
So "we" need a card, but "they" have to pony up the resources and infrastructure to make it happen? If "you" see the need and the utility, figure out some way to contribute (if possible, besides buying lots of their cards).
Here's a question: Could an open source video processor be designed purely around OpenGL and still be viable in this age - i.e. with many games being developed around DirectX9, would an OpenGL-only design be good enough?
Cool? Sure. The technology that will save us? NOT.
on
Jet Engine on a Chip
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· Score: 1
What developing countries (and us) really need is NOT another technology that requires petroleum/gas refinery infrastructure. I don't have the background but it would be interesting to do a cost-benefit tradeoff between existing lithium-ion battery technology vs. portable turbine generator technology. Costs, of course, include the energy put into making the batteries and turbine/generators, as well as the industrial effluent from the plants that make the parts for both.
Real progress will be made when you can teach someone with little prior education how to build a generator or water pump from stuff that he or she can find within a 10 mile radius from their house.
We built a small RF anechoic chamber inhouse. Got a shielded room from eBay, bought RF absorbers new from the manufacturer (that is expensive), built a 3D rotator gimbal using plexiglas sheet and a nylon sprocket and chain drive, got an HP 8566B on eBay, built our own broadband antenna, and had a custom broadband LNA built. We can test effectively up to about 12 to 13 GHz, and if we need to we can go higher, but our chamber is too small to meet certification requirements, so we still have to send our stuff out for official approval.
The main thing that we've found over the last few years is that (a) Sometimes the FCC test house that you send your stuff to does the tests wrong, or with improperly calibrated equipment, and they may say that you fail where you should have passed. (b) You can't trust a manufacturer's reference design to have good harmonic performance, so while you're getting good range, you may also be contaminating the second and third harmonic bands with crap. (c) When you have your own anechoic chamber, you can do development and tuning much more quickly than having to outsource that stage of product design. We never intended to be an RF design company, but since our products use wireless technology, we really couldn't do without an investment in basic RF test equipment, and from there it was a series of small steps to where we are now.
Slashdot Mirror
Most elements with atomic mass less than or equal to that of uranium have at least one "stable" isotope, and an element's nuclear characteristics doesn't influence its chemical reactivity. I think TFA was talking about stability vs. reactivity on a chemical level.
Unless you're talking about having to provide breastfeeding for a newborn, there is little difference between the amount of time and energy a woman or a man "could" commit to work or any other activity, provided they had the necessary drive. Committing 80 hours a week to work by anyone demands a significant sacrifice on the part of both folks in a marriage, and if both people don't agree on why that commitment is being made, then it's going to cause big problems. By the way, 80 hours a week for at least couple of years is par for the course, if you're one of the principals doing a startup. Research isn't the only thing that requires obsession.
If it could be applied densely enough (maybe if you had a very densely finned heatsink with the material deposited onto all the fin surfaces), and if the material itself had sufficient power density capability. I'm assuming it's converting IR photons into electrical energy by stimulating a potential difference somehow - I'm not a theoretical physicist. Maybe it's like a reverse laser?
This would be different from a thermocouple because from what I can tell it's not based on junctions between two different metals, and it's not based on having a hot junction and a separate cold junction.
In Canada, there are also differences in culture, slang, and societal norms as you go from the Atlantic provinces to the densely (as in "lots of", not "thick-headed" ;) ) populated regions of Ontario and southwest Quebec, to the prairies and the Pacific. People from Ontario are regarded with some initial mistrust in Alberta, while folks from Alberta are regarded as redneck simpletons in Toronto. The US has just as many regional characteristics, and it's only natural that people from Canada will trigger a "you're not from around here, are you?" response from a lot of US citizens, and vice versa.
Most of the time it's not an unwelcoming thing - people are just curious. The few cases where people take a stand against people from different parts of the country or the world are almost always due to the government trying to help, and instead raising fears among the locals that something is getting taken away from them to the advantage of others. In Canada, the various provinces contribute or get "equalization payments" that are regulated by the federal government, and one of the things that does is to give the perception (if not the actuality) that the have-not provinces are being subsidized to maintain an above-practical level of population and industry at the expense of the other provinces.
The memory structure and processing paradigm in most computers is also quite different from what we know of the human thought process. The computer uses binary logic to carry out its operations, while the brain, as far as we know, uses a complex system of neural-net interaction. NN simulations have shown learning and recognition ability that is similar to that of humans, but since it is not easy to mimic, program, or teach the interaction of billions of neurons, large neural nets are not commonplace.
Anthropomorphizing (?) the memory systems of a computer as "short term" and "long term" and associating that with RAM and hard drives is fallacious. The RAM will retain information for as long as the power is applied, which can be just as long or longer than the magnetic media on the hard drive will retain its state. If you remove power from a human (don't try this at home... ) you'll lose both short and long term memory pretty much simultaneously.
Etcetera.
When the developers are forced to spend money like it's their own, rather than the government's, it is more likely that groups will shoot for little incremental successes rather than trying radically new technologies all in one go. SpaceShipOne's success was not due to it adopting a (sorry) pie-in-the-sky approach - it just brought some well established technologies together in an optimal way. Similarly, Armadillo's work toward VTOL rockets with real throttleable engines is breaking ground and putting pieces in place for future space industry development.
Private development gets done because the business owners believe that their stuff will eventually be able to meet the industry requirements. The government's current method of allocating project funds seems too biased toward technology development and not enough towards results.
In WW2, the British and to some extent the Americans put a huge dent in the German advance by having a very good understanding of the psyche of their opponents and of their command structure. Both sides had radar as far back as 1940, but the British used it much more effectively and designed a defense system around it that optimally combined what little resources they could bring to the situation at that time.
The various deceptions that were devised by the British went largely undetected by the Germans, and while their impact is difficult to measure in lives saved, there is little doubt that various decoys and false transmissions in the right places allowed the Allies to attack more effectively at a low cost in extra manpower.
The point is that defeating your opponent is as much (or more) a mind game as it is a matter of brute strength. Robots, even with remote control, aren't going to have the agility or cunning required to survive on the battlefield.
Hi
BBC Link to an article that has a partial picture of the beast. Not slashdotted ... yet.
Up here in Canada the cars are marketed through Mercedes as well. It's not especially clear to me why DaimlerChrysler wouldn't brand it at least as a Chrysler/Dodge model... Chrysler has been importing vehicles and rebranding them as their own (Mitsubishi, etc) for decades.
This picture would suggest that the dolphin didn't actually lose any skeletal structure.
There's quite a bit going on both in the academic world and by prosthetics manufacturers. One of the bigger struggles is getting an amputee a prosthetic that's suitable for what they're going to be doing - a foot optimized for running looks a lot different from a foot that's designed to look like a foot and that you'd wear with ordinary footwear.
Without turning this into a shill for our products, the company I work for makes an inertial-sensor based activity monitor that helps doctors choose an appropriate prosthetic depending on the patient's activity profile. This is one of our customers
The guy who designed the SR-71's engines ended up winning one of the most prestigious aviation prizes (no, I can't remember which) for the way that the movable engine inlets ended up being responsible for something like 80% of the thrust produced at high speeds. He later became director of the Lockheed Skunkworks in the era where they produced the F117A.
OK then... How about if the British (or anyone else with the required steel foundry infrastructure) resurrected the Tallboy or Grand Slam bombs used in WW2? Put a few of these into space in orbits that give decent time-to-target, and all you have to do is de-orbit them at the right time. If you can drop them from low earth orbit, then you don't even need any explosive. A ten-ton half-molten ingot dropping on a concrete bunker at several times the speed of sound has got to hurt.
On 80x86 platforms, ints were 16 bits. Even now, if you use a tool such as Borland to compile PC apps, and the code generation is set to 80386 (which is the default), you may still get 16 bit ints - I don't remember, and if I really need to worry about it I use 'short' or 'long' as the case may be.
On the M68K, it depended more on which toolset you used, since the register set inherently was 32 bits wide. IIRC Sun compilers gave 32 bit ints by default, while Diab and some others gave 16 bit ints.
Well, this is what Wikipedia has to say about it. In short, yes, for historical reasons. Occasionally we (here at work) will use 'order of magnitude' in a specific context where it means a factor of two, but that's by no means common usage.
Not likely. If you assume that the jamming approach is to beam noise at the satellite in the frequency range it's designed to accept, then the power required to jam its receiver compared to what is required to damage the thing is at least a couple of orders of magnitude (factors of 10) different.
Jamming the satellite's transmissions in a certain terrestrial location simply involves having localized noise generators in the same frequency band as the satellite in question. Or, for world-wide coverage, just launch a satellite(s) in a compatible orbit to the target satellite, and broadcast away.
Take several engineering courses on thermodynamics and properties of materials, design and build your own turbosystem, and then drive it without problems for a couple of years. When we're on even ground you can explain to me again how turbos work.
Based on doing a LOT of dyno testing and a couple thousand laps of track time at the local road course, I would suggest that unless you have a large crew and the budget to build multiple versions of things that you want to test with, keeping it to 'one factor at a time' is by far the fastest way to get results. At the track, a one percent improvement in lap speed is pretty significant, but there are many factors that can make more than one percent difference in engine power or available traction, and then any improvement you're looking for will be lost in the noise, skewed by incidental factors, or they'll be so correlated that you can't tell what caused what. Even if you're testing on the dyno, which eliminates driver errors, nobody will ever suggest that you should go do a set of runs where you're changing the timing and the mixture at the same time. At least part of the reason for that is that engine tuning is not a linear problem - just because the engine likes 38 degrees BTDC on a lean mixture doesn't mean that it will work best at 38 degrees when you have the mixture right.
The other think about multiple factor testing is that it can take serious time to prepare multiple items to test. For example, if you're trying to adjust sway bars, then ideally you'd have a range of bars ready at the track and you could swap them out and do tests. The problem with that is that a lot of practice time at tracks is limited to 15 or 20 minute sessions, and it's hard to do multiple bar swaps in that time.
About a decade and a half ago a group of us were heavily involved in club racing at the local road course. There were many onlookers with no end of advice on how our cars weren't as suitable for racing as their (whatever), and that if they came out they'd keep up no problem. From time to time one of the onlookers would actually put in the time and effort to race-prep their cars, and then they'd find out that there was a reason why we spent a lot of evenings and weekends doing fabrication and dyno tests. Going fast is hard, and figuring out what works takes time and money.
A turbocharger uses exhaust heat energy to drive an intake air compressor, and thereby recovers some of the 25 percent or more of the fuel's BTU content that goes straight out of the tailpipe. Typically the turbo configuration is sized towards the performance end of the spectrum, but if you pick a more street oriented compressor, you will improve the cruising efficiency compared to a naturally aspirated engine as well as having some serious power at your disposal when you put your foot in it. If you want to just increase your mileage, then drop the engine displacement when you install the turbo - your cruising mileage will be governed more-or-less by the engine size and configuration (number of cylinders, inline or vee, etc), and the peak power is determined by how much boost you run.
The acceleration you can get from your car depends a lot on the rotational inertia of the various driveline parts. A lighter wheel/tire combination will reduce the rotating inertia so that you can spin everything up to speed more quickly. A lighter flywheel and clutch also contribute significantly to faster acceleration. Faster acceleration means you burn less gas while getting up to speed, so you will get better mileage especially around town. Reducing the weight of your car's body and interior will generally improve acceleration as well, but it also decreases the comfort level, so you'll be making a choice there between fast or cozy.
I'm not sure how different the two specs are, but if (for instance) DX9 and OpenGL 1.3/1.5/2.0 had different word-lengths defined for color precision, then you could advantageously design the hardware to support those word lengths natively. Implementing OpenGL word-lengths in hardware and not DX9 would simplify the required drivers and speed up operation for OpenGL over DX9. If, of course, there is a difference.
So "we" need a card, but "they" have to pony up the resources and infrastructure to make it happen? If "you" see the need and the utility, figure out some way to contribute (if possible, besides buying lots of their cards). Here's a question: Could an open source video processor be designed purely around OpenGL and still be viable in this age - i.e. with many games being developed around DirectX9, would an OpenGL-only design be good enough?
Real progress will be made when you can teach someone with little prior education how to build a generator or water pump from stuff that he or she can find within a 10 mile radius from their house.
The main thing that we've found over the last few years is that
(a) Sometimes the FCC test house that you send your stuff to does the tests wrong, or with improperly calibrated equipment, and they may say that you fail where you should have passed.
(b) You can't trust a manufacturer's reference design to have good harmonic performance, so while you're getting good range, you may also be contaminating the second and third harmonic bands with crap. (c) When you have your own anechoic chamber, you can do development and tuning much more quickly than having to outsource that stage of product design. We never intended to be an RF design company, but since our products use wireless technology, we really couldn't do without an investment in basic RF test equipment, and from there it was a series of small steps to where we are now.