It sez in the TFA that NASA will "carefully land (their helicopters) upwind of the capsule", presumably so they don't get contaminated by anything that might be on or leaking from the capsule. Of course, in the process they will blow salty crap all over the capsule and hopelessly contaminate it. They should land crosswind from it, so they don't contaminate it, and they also won't catch anything that might be leaking from the capsule...
Like crypto, excessive legislation and draconian enforcement in the digital rights management scene will just drive software and hardware development (as well as independent filmmmaking) out of the US... you guys down there need to wake up your senators and other government reps and explain to them that they're killing the tech industry just so that the bigwig media machine can make its crappy "entertainment".
The ring of ejected particles you're talking about is pretty much the expected result for any object impact. Those particles follow a roughly parabolic trajectory (which is what you're describing as a 'sine wave'), due to gravity. The unexpected result and the discovery have to do with the vertical jet that is visible in the center of the third frame (top and bottom), and not anything to do with the outer ring of material.
Ugly code is hard to maintain, and hard to understand, hard to scope for vulnerabilities, and it's hard to test in a controllable way. There is a lot of merit to the notion that when code gets to a certain age, it's worth looking at what requirements that piece of code actually fulfills in the context of the current environment, and to figure out if an underlying change in architecture would clean up the implementation.
Code itself doesn't rust when it gets old, but the coders get rusty... and there will always be new coders being handed old crap and getting told to "fix" it, without them having enough of the background story to properly appreciate all the implications of whatever barnacle they might add on.
Exactly! Start the terraforming process by slagging Mars with about half the contents of the asteroid belt. You'd get the increased mass and ferromagnetic material but you'd have to wait a while for the surface to re-form... It would be an interesting orbital-mechanics problem to do this (geologically speaking in a short period of time) and at the same time maintain Mars' orbit and rotation.
Alternators are pretty efficient. The power output of an alternator is controlled by how much current you apply to the field windings. The field current, in turn, is controlled by a voltage regulator, which maintains the car or truck's electrical system at about 13.5 to 14 volts, which is what's necessary for optimal battery charging. In this way, the alternator produces exactly the right amount of energy to run the electrical accessories, as well as maintaining a good battery charge. The mechanical to electrical conversion process is about 90 percent in a good alternator, and the belt drive is also pretty efficient if the tension is properly maintained. All in all, the alternator takes exactly as much energy from the engine as it needs, all the time, so there is never any "wasted" electrical output as such.
OK... on thinking about it(!) it seems like some solenoid-like arrangement might offer the correct geometric properties. Still - what is "huge" when it comes to the current requirement? Thousands of amperes? If you can continually pull on the ISS, you probably don't have to pull too hard to keep it in orbit.
Here's a dumb idea: Hook a long coaxial cable with a sizable mass (how about a dead satellite?) onto the ISS. Then feed electrical power through the cable (up the center, down the outer jacket) so that the vector crossproduct of the current and the earth's magnetic field act to accelerate the ISS. How much power is required to keep the orbit from decaying, i.e. can this power be reasonably supplied by the existing or an additional solar array? A scheme like this would reduce or eliminate the dependence on periodic orbit boosts by cranky Russian rockets or once-in-whenever Space Shuttle flights.
I got that part... However, four engines quadruple the fuel consumption, and as it turns out I was wrong... the prototype uses eight engines. At eighty liters per hour, even at 200 MPH (which is actually a pretty good clip for a general-aviation type aircraft) you're getting under 10 MPG.
Since each engine (or each pair... not totally clear) drives one ducted fan assembly, you don't have a lot of redundancy unless it can be shown that you can effectively differentially-thrust the engines to maintain stability even if you lose one of the four thruster pods.
Presently all test flights of the M400 Skycar employ a safety tether from above to protect the vehicle from catastrophic failure. Certainly during these early tests there are a number of failure modes with an aircraft that has 24 microprocessors and 25,000 lines of machine language software code.
The SkyCar was (is?) powered by four hopped-up Mazda rotary (Wankel) engines. These were never either frugal, or quiet - especially if they're ported for increased performance.
It isn't necessary for software people to know hardware, and visa versa. Both fields have become complex enough to function independently.
This flawed assumption is why the really interesting problems still exist at the hardware-software interface level. Since the purpose of a computer system is to solve data processing or control-system type problems, its overall efficiency depends greatly on not having difficult-to-overcome architectural bottlenecks at any level. It only takes one or two bad hardware oversights to make writing efficient software for the system impossible. It is surprising how often this kind of thing surfaces even on embedded micros designed by companies with years of experience.
I was remiss in not mentioning the gate capacitance, since that is the major contributor to the dynamic power consumption in a large CPU, but 'shoot-through' is a significant factor in any high speed CMOS design, even when the process has been tweaked to minimize its occurrence. As an example, the TI MSP430 has a feature where the I/Os that can be configured as either analog or digital inputs, can have the digital inputs disconnected in order to eliminate the extra power consumption that would occur due to having an analog signal near mid-rail.
In a CMOS chip, the power consumption is a function of two major items: The leakage current, and the switching current. The leakage current is a function of the operating voltage and the device geometry size. Going smaller and lower voltage has increased the leakage current to the point where it's a roadblock to further development, so Intel is now apparently addressing it... that's good. The switching current comes about because the CMOS logic state for any node is controlled by either a transistor connecting the node to the supply rail, or a different transistor connecting that node to the ground rail. When the node is switched from one rail to the other, there is a brief period where both transistors partially conduct, and the current goes up dramatically. Hence, the more switching that goes on, the more rapidly, the more current is used, and that's the "power used for computing". The switching current is reduced by, among other things, lowering the operating voltage, which puts it at odds with the reduction of leakage current.
That's not correct - you're thinking of SAGD extraction (steam-assisted gravity drainage) or something like it, which has been done in Wyoming at great ecological cost.
The tarsands are worked as an open pit mine. BIG Bucket wheels, draglines, and shovel-and-dump-truck operations get the overburden off of the tar sands. Then the tar sand and some regular sand (the shovel operators judge the mix by eye) are put in 300 ton dump trucks and taken to the central processing operation where it's mixed with water and heated to separate the oil from the sand. Afterward the sand and the overburden are put back, but it still takes a long time for things to regrow.
Been there, rode the shovel, surveyed the mine roads with GPS. It's a damn impressive operation.
A lot of point-of-sale cash registers print the card number onto the receipt. "Good" machines obliterate part of the number, but a lot of them don't, and so the thief could (1) take the PIN, then (2) wait until the user dumps his receipts in the trash, and then get the card number. Simply program that number onto a blank card, and you're set.
Of course this assumes that the user doesn't change the PIN as soon as they get the card... but a lot of folks don't.
NASA has 20,000 people on staff to maintain and rebuild the Shuttle fleet. Given that loaded labor rates, even for drudgery such as rocket maintenance, are probably in the $75k to $100k per year range, that means $1.5B per year is getting spent whether the Shuttles fly or not.
By the way: Loaded labor rate includes all expenses attributable to the employee being there - the cost of their desk, computer(s), health plan, the portion of the air conditioning and heating bill for their space, etc. It's part of what makes large organizations exponentially more expensive to operate than a one or two person garage business.
Even if total internal reflection were 100% efficient (and it can't be), you'd be left with an interesting problem... How do you get the light in? The refractive index of glass is such that the angle of an incident light beam gets closer to normal (perpendicular to the interface plane), compared to the source. So shining a beam of light onto the surface of a perfect quartz torus (of arbitrary length or number of turns) will just cause most of the beam to be refracted such that it can exit on the opposite torus wall. The remainder of the beam will get internally reflected, but at pretty close to the critical angle, and then you can't get it out...
If the reflection and transmission of light in a particular crystal were any given number of 9's (i.e. 0.9999999999999999999...90), it would still only take a finite number of reflections or molecular interactions for the photon to lose it's energy to the crystal as heat.
One good idea (for the whole light-pipe business) would be to take the UV energy that is reflected or filtered, and use it to energize a fluorescent radiator whose output could then augment the visible light collected by the system. Since there are some fluorescent materials with extended decay times, that might buy you some 'charge' time.
The speed of light is 300 million meters per second. As long as your definition of 'a while' is in the millisecond range, you're in business.
The 'infinite light trap' is an interesting notion, but since the mirrors would absorb a small fraction of the incident energy with every photon reflection, you wouldn't be able to store a lot of energy until things got really hot.
One thing that might work is to trap photons inside a slow-light crystal, but I think that conservation of energy would still have to apply, and you'd quickly find out that collecting solar power in a small volume gets things HOT.
Google may trust Mindpixel, but I sure don't have to. Not when you're claiming that blue and yellow make green (about 0.95 probability), without qualifying that it only applies to pigments.
2005: Booster fails - the solar sail never gets a chance.
2001: Booster separation fails - the solar sail never gets a chance.
1999: Deployment mechanism jammed - the solar sail never gets a chance.
The solar sail part of the experiment hasn't had too many flight hours so far, due to component failures almost completely unrelated to the solar sail craft itself. They're not launching failure after failure... they're having launch failures, which is not the same thing.
Slashdot Mirror
It sez in the TFA that NASA will "carefully land (their helicopters) upwind of the capsule", presumably so they don't get contaminated by anything that might be on or leaking from the capsule. Of course, in the process they will blow salty crap all over the capsule and hopelessly contaminate it. They should land crosswind from it, so they don't contaminate it, and they also won't catch anything that might be leaking from the capsule...
Like crypto, excessive legislation and draconian enforcement in the digital rights management scene will just drive software and hardware development (as well as independent filmmmaking) out of the US... you guys down there need to wake up your senators and other government reps and explain to them that they're killing the tech industry just so that the bigwig media machine can make its crappy "entertainment".
The ring of ejected particles you're talking about is pretty much the expected result for any object impact. Those particles follow a roughly parabolic trajectory (which is what you're describing as a 'sine wave'), due to gravity. The unexpected result and the discovery have to do with the vertical jet that is visible in the center of the third frame (top and bottom), and not anything to do with the outer ring of material.
Ugly code is hard to maintain, and hard to understand, hard to scope for vulnerabilities, and it's hard to test in a controllable way. There is a lot of merit to the notion that when code gets to a certain age, it's worth looking at what requirements that piece of code actually fulfills in the context of the current environment, and to figure out if an underlying change in architecture would clean up the implementation. Code itself doesn't rust when it gets old, but the coders get rusty... and there will always be new coders being handed old crap and getting told to "fix" it, without them having enough of the background story to properly appreciate all the implications of whatever barnacle they might add on.
Exactly! Start the terraforming process by slagging Mars with about half the contents of the asteroid belt. You'd get the increased mass and ferromagnetic material but you'd have to wait a while for the surface to re-form... It would be an interesting orbital-mechanics problem to do this (geologically speaking in a short period of time) and at the same time maintain Mars' orbit and rotation.
Alternators are pretty efficient. The power output of an alternator is controlled by how much current you apply to the field windings. The field current, in turn, is controlled by a voltage regulator, which maintains the car or truck's electrical system at about 13.5 to 14 volts, which is what's necessary for optimal battery charging. In this way, the alternator produces exactly the right amount of energy to run the electrical accessories, as well as maintaining a good battery charge. The mechanical to electrical conversion process is about 90 percent in a good alternator, and the belt drive is also pretty efficient if the tension is properly maintained. All in all, the alternator takes exactly as much energy from the engine as it needs, all the time, so there is never any "wasted" electrical output as such.
Try MirrorDot
'Cause they slashdotted the announcement page?
OK... on thinking about it(!) it seems like some solenoid-like arrangement might offer the correct geometric properties. Still - what is "huge" when it comes to the current requirement? Thousands of amperes? If you can continually pull on the ISS, you probably don't have to pull too hard to keep it in orbit.
Here's a dumb idea: Hook a long coaxial cable with a sizable mass (how about a dead satellite?) onto the ISS. Then feed electrical power through the cable (up the center, down the outer jacket) so that the vector crossproduct of the current and the earth's magnetic field act to accelerate the ISS. How much power is required to keep the orbit from decaying, i.e. can this power be reasonably supplied by the existing or an additional solar array? A scheme like this would reduce or eliminate the dependence on periodic orbit boosts by cranky Russian rockets or once-in-whenever Space Shuttle flights.
They have it: Mirrordot front page. You do have to get the PDF to see the corrected picture...
I got that part... However, four engines quadruple the fuel consumption, and as it turns out I was wrong... the prototype uses eight engines. At eighty liters per hour, even at 200 MPH (which is actually a pretty good clip for a general-aviation type aircraft) you're getting under 10 MPG. Since each engine (or each pair... not totally clear) drives one ducted fan assembly, you don't have a lot of redundancy unless it can be shown that you can effectively differentially-thrust the engines to maintain stability even if you lose one of the four thruster pods.
Presently all test flights of the M400 Skycar employ a safety tether from above to protect the vehicle from catastrophic failure. Certainly during these early tests there are a number of failure modes with an aircraft that has 24 microprocessors and 25,000 lines of machine language software code.
Sounds like they need a software QA audit...
The SkyCar was (is?) powered by four hopped-up Mazda rotary (Wankel) engines. These were never either frugal, or quiet - especially if they're ported for increased performance.
This flawed assumption is why the really interesting problems still exist at the hardware-software interface level. Since the purpose of a computer system is to solve data processing or control-system type problems, its overall efficiency depends greatly on not having difficult-to-overcome architectural bottlenecks at any level. It only takes one or two bad hardware oversights to make writing efficient software for the system impossible. It is surprising how often this kind of thing surfaces even on embedded micros designed by companies with years of experience.
And no, that doesn't rhyme in Dutch. ;)
I was remiss in not mentioning the gate capacitance, since that is the major contributor to the dynamic power consumption in a large CPU, but 'shoot-through' is a significant factor in any high speed CMOS design, even when the process has been tweaked to minimize its occurrence. As an example, the TI MSP430 has a feature where the I/Os that can be configured as either analog or digital inputs, can have the digital inputs disconnected in order to eliminate the extra power consumption that would occur due to having an analog signal near mid-rail.
In a CMOS chip, the power consumption is a function of two major items: The leakage current, and the switching current. The leakage current is a function of the operating voltage and the device geometry size. Going smaller and lower voltage has increased the leakage current to the point where it's a roadblock to further development, so Intel is now apparently addressing it... that's good. The switching current comes about because the CMOS logic state for any node is controlled by either a transistor connecting the node to the supply rail, or a different transistor connecting that node to the ground rail. When the node is switched from one rail to the other, there is a brief period where both transistors partially conduct, and the current goes up dramatically. Hence, the more switching that goes on, the more rapidly, the more current is used, and that's the "power used for computing". The switching current is reduced by, among other things, lowering the operating voltage, which puts it at odds with the reduction of leakage current.
The tarsands are worked as an open pit mine. BIG Bucket wheels, draglines, and shovel-and-dump-truck operations get the overburden off of the tar sands. Then the tar sand and some regular sand (the shovel operators judge the mix by eye) are put in 300 ton dump trucks and taken to the central processing operation where it's mixed with water and heated to separate the oil from the sand. Afterward the sand and the overburden are put back, but it still takes a long time for things to regrow.
Been there, rode the shovel, surveyed the mine roads with GPS. It's a damn impressive operation.
Of course this assumes that the user doesn't change the PIN as soon as they get the card... but a lot of folks don't.
By the way: Loaded labor rate includes all expenses attributable to the employee being there - the cost of their desk, computer(s), health plan, the portion of the air conditioning and heating bill for their space, etc. It's part of what makes large organizations exponentially more expensive to operate than a one or two person garage business.
One good idea (for the whole light-pipe business) would be to take the UV energy that is reflected or filtered, and use it to energize a fluorescent radiator whose output could then augment the visible light collected by the system. Since there are some fluorescent materials with extended decay times, that might buy you some 'charge' time.
The 'infinite light trap' is an interesting notion, but since the mirrors would absorb a small fraction of the incident energy with every photon reflection, you wouldn't be able to store a lot of energy until things got really hot.
One thing that might work is to trap photons inside a slow-light crystal, but I think that conservation of energy would still have to apply, and you'd quickly find out that collecting solar power in a small volume gets things HOT.
Google may trust Mindpixel, but I sure don't have to. Not when you're claiming that blue and yellow make green (about 0.95 probability), without qualifying that it only applies to pigments.
2005: Booster fails - the solar sail never gets a chance.
2001: Booster separation fails - the solar sail never gets a chance.
1999: Deployment mechanism jammed - the solar sail never gets a chance.
The solar sail part of the experiment hasn't had too many flight hours so far, due to component failures almost completely unrelated to the solar sail craft itself. They're not launching failure after failure... they're having launch failures, which is not the same thing.