Would this make ocean-going ground-effect aircraft (a la Ekranoplans) viable? It could create a third tier of shipping in between ship and air.
Assuming, of course, that the necessary data can be gathered while traveling across the waves at several hundred mph.
I've used Soekris hardware extensively with Strongswan IPSec at work. I love the boards, but a large number of our Internet circuits are now faster than the net5501 and net6501 can soak with AES IPSec. The net5501 is good for about 8Mbit/sec and the net6501 is good for about 25Mbit/sec with our firewall ruleset and some dynamic routing thrown into the mix. I'm looking forward to the net6801 when it comes out, but in the meantime for those circuits I've been building whitebox 1U routers that have CPUs with AES-NI support (which can easily soak several gigabit/sec). These can be low-power solid state too - recently we've been ordering the Supermicro A1SRi-2758F boards, which have the new Rangeley Atom CPUs, 4 gigabit ethernet ports, and no fans. Just add an SO-DIMM and a USB stick to boot off of, and stick in a 1U short-depth mini-ITX case (I like the Supermicro CSE-505-203B, which puts everything but the power socket in the front).
Java updates every 3 months. Every release they do fixes a gaggle of remote-exploit-without-authentication security holes, and comes with a warning such as "Due to the severity of these vulnerabilities, and the reported exploitation of CVE-2013-1493 "in the wild," Oracle strongly recommends that customers apply the updates provided by this Security Alert as soon as possible." Exactly what reason do you have to believe that their latest release not only has no known vulnerabilities at the time of that release, but will have no known vulnerabilities for the entire time that that release is current, when there has been evidence to the contrary for *every* past release for *years*?
I was curious so I did the math. sqrt(297) is 17.2, ergo, the light is concentrated from an area which is at most 35mm square. There's no details here about what the focal length is. With a fresnel lens it can be quite short, but let's say it's f/1 and your focal length is 35*sqrt(2)=50mm.
The most extreme day-to-day movement in an analemma is slightly less than 0.4 degrees, at or around the equinoxes. At f=50mm, 0.4 degrees will put you 0.35mm off center. It's very likely the beam is focused onto most of the square rather than just the center, so you will lose a bit of power (certainly not all of it) by only setting it every two days near the equinoxes. Constant tracking throughout the day is certainly not necessary.
It is, however, worth comparing a photovoltaic conversion of solar to grid power to a heat engine conversion of solar to grid power, particularly when the latter currently holds the world record for efficiency for that particular conversion.
Assuming you rig the axes in a polar alignment, you only need to set one of the axes (ascension) constantly. The other (declination) can be adjusted every few days (less often if you are concentrating fewer suns, i.e. have a bigger target to hit). Also if you use these in a linear format (analogous to the parabolic trough mirror setups) then you don't need to track constantly on the ascension axis either.
Starting a car uses less than 1% of the car's battery capacity (source: go on Youtube and look for videos of people who have replaced their car's lead-acid battery with a much smaller array of supercapacitors). Ergo, a car that only has a small fraction of its battery capacity remaining is OK, but a laptop that only has a small fraction of its battery capacity remaining is not.
That current-carrying capacity will manifest as an extremely low ESR (equivalent series resistance). For this application, CanHasDIY would want to ignore any parts that don't spec that.
Because it's a 1/1.5" sensor (3.93 crop factor) at its widest focal length and 1/4.5" at it's narrowest, with an f/2.2 lens, which means a relatively small ~3mm aperture which will necessarily yield muddy pictures, similar to most point-and-shoots?
Maybe you can, at least, put the 2nd UPS on a different phase (if L-N connected like 120 volts in NA or 230 volts in EU) or phase pair (if L-L connected like 208 volts in NA or 400 volts in EU if that's a step-down UPS). That way you have a chance of ridding through single phase outages which sometimes happen.
Some big caveats to this:
In North America, residential power is "split-phase" which is still considered single phase - it is a pair of hot wires delivered to you, with neutral off the center tap of the transformer on the pole, tied to ground at the service entrance. It's actually very rare for just one of those phases to die (I have yet to see it happen), as it would require a break in one of the hot wires running from your house to the pole. These are low voltage lines so they are typically bundled together, so if run aerially, a tree would snag both of them at once, and if underground a flood would damage both at once. A dead transformer or a dead power line anywhere upstream of the transformer would kill power to both.
Three-phase failure modes often leave you with only one phase out of three working, but never two. This is regardless of whether you are drawing phase-to-neutral power or phase-to-phase power. Imagine the phases of a three-phase system as three dots in a triangle, and the connections between those dots are the power you can draw. If one of the dots goes away, you're left with just one remaining connection between the remaining pair of dots. Remember the neutral is only generated locally at the transformer, so it does not provide any sort of redundant path for anything outside of the building.
Not in the last 7-8 years it hasn't. I tried for 3 hours on the phone to get a laptop hard drive replaced under next-business-day warranty. They wouldn't budge, because I couldn't produce the output of the diagnostic tools that were loaded *on that hard drive*. In the end, we got the replacement drive when they felt they could get around to it.
These days, there's little point to getting a hot-swap RAID server from Dell, because to get a replacement drive from them they will ask you to take the server offline and run the diagnostic checks on it. This is a far cry from 10+ years ago when I got replacement drives via UPS SonicAir over holiday weekends.
Another way to calculate this: Google "c/1.8GHz" and it'll give you the result in centimeters. Then just divide by two to get a half-wavelength dipole or divide by 4 to get a 1/4-wave ground plane length.
If you want a high-gain directional antenna for >1GHz you're probably best off with a dish, perhaps using a cantenna-like feed horn.
of course, these days, for anyone in the building trade to quotes believe quotes that this is even remotely possible would require supercomputers and fluid dynamics analysis
Or a small scale-model wind tunnel that could cheaply and easily be built with some plywood, some fans, and maybe some smoke or thread to show wind direction. It shouldn't cost more than $100.
You sound like you have something to prove here. Get on it.
Now, to properly compare apples to apples, look at this graph (on page 10) regarding the Prius motor's efficiency at various power outputs (you've probably already seen this since you mentioned it earlier). Below 5kW, it's at 25%. At 10kW, it's at 33%, and that's a realistic highway speed power output. If we can assume 33%*90% (drivetrain) we get 29.7% - with a 38% Stirling engine, if we get 90% from the rest of the system (generator, battery, controller, wiring) - and I've already posted links showing that's do-able - then if your motor exceeds 87% efficiency you come out ahead. At 5kW output you just need 67% motor efficiency to come out ahead. It's nearly a wash, plus there's lots of tricks you can pull with electric motors when you have a handful of them (vs just one engine).
It's not theoretical best case when it's already been done, and I was not cherry picking numbers. Here's some that are closer to the state of the art, for comparison: A 99% efficient BLDC controller - most of the controller inefficiencies are from band-gap voltage drop, which gets smaller as you use higher voltages (as does resistive losses in the wiring). Here's a 98% efficient motor, used on the CSIRO-UTS solar racer..
90% is too conservative. Brushless DC motors (the sort you'd pair with a VFD in any electric car) are pushing 96%:
http://www.ti.com/ww/en/motor_drive_and_control_solutions/motor_control_type_brushless_dc_BLDC.htm. Lithium Ion battery efficiency is, depending on your source, 95% or 97-99%. So your 27% figure could be 34%. More importantly, since you have a drivetrain capable of driving the car at highway speeds in pure electric mode (something current parallel hybrids lack), a series hybrid could potentially be cheaper to operate if charged at night, and you can recoup more energy through regenerative braking.
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Would this make ocean-going ground-effect aircraft (a la Ekranoplans) viable? It could create a third tier of shipping in between ship and air. Assuming, of course, that the necessary data can be gathered while traveling across the waves at several hundred mph.
I've used Soekris hardware extensively with Strongswan IPSec at work. I love the boards, but a large number of our Internet circuits are now faster than the net5501 and net6501 can soak with AES IPSec. The net5501 is good for about 8Mbit/sec and the net6501 is good for about 25Mbit/sec with our firewall ruleset and some dynamic routing thrown into the mix. I'm looking forward to the net6801 when it comes out, but in the meantime for those circuits I've been building whitebox 1U routers that have CPUs with AES-NI support (which can easily soak several gigabit/sec). These can be low-power solid state too - recently we've been ordering the Supermicro A1SRi-2758F boards, which have the new Rangeley Atom CPUs, 4 gigabit ethernet ports, and no fans. Just add an SO-DIMM and a USB stick to boot off of, and stick in a 1U short-depth mini-ITX case (I like the Supermicro CSE-505-203B, which puts everything but the power socket in the front).
This is definitely worth noting! It's really sad that they haven't had a release since 6.0.2 that didn't fix a critical security hole.
Java updates every 3 months. Every release they do fixes a gaggle of remote-exploit-without-authentication security holes, and comes with a warning such as "Due to the severity of these vulnerabilities, and the reported exploitation of CVE-2013-1493 "in the wild," Oracle strongly recommends that customers apply the updates provided by this Security Alert as soon as possible." Exactly what reason do you have to believe that their latest release not only has no known vulnerabilities at the time of that release, but will have no known vulnerabilities for the entire time that that release is current, when there has been evidence to the contrary for *every* past release for *years*?
I was curious so I did the math. sqrt(297) is 17.2, ergo, the light is concentrated from an area which is at most 35mm square. There's no details here about what the focal length is. With a fresnel lens it can be quite short, but let's say it's f/1 and your focal length is 35*sqrt(2)=50mm. The most extreme day-to-day movement in an analemma is slightly less than 0.4 degrees, at or around the equinoxes. At f=50mm, 0.4 degrees will put you 0.35mm off center. It's very likely the beam is focused onto most of the square rather than just the center, so you will lose a bit of power (certainly not all of it) by only setting it every two days near the equinoxes. Constant tracking throughout the day is certainly not necessary.
It is, however, worth comparing a photovoltaic conversion of solar to grid power to a heat engine conversion of solar to grid power, particularly when the latter currently holds the world record for efficiency for that particular conversion.
Assuming you rig the axes in a polar alignment, you only need to set one of the axes (ascension) constantly. The other (declination) can be adjusted every few days (less often if you are concentrating fewer suns, i.e. have a bigger target to hit). Also if you use these in a linear format (analogous to the parabolic trough mirror setups) then you don't need to track constantly on the ascension axis either.
Starting a car uses less than 1% of the car's battery capacity (source: go on Youtube and look for videos of people who have replaced their car's lead-acid battery with a much smaller array of supercapacitors). Ergo, a car that only has a small fraction of its battery capacity remaining is OK, but a laptop that only has a small fraction of its battery capacity remaining is not.
That current-carrying capacity will manifest as an extremely low ESR (equivalent series resistance). For this application, CanHasDIY would want to ignore any parts that don't spec that.
Because it's a 1/1.5" sensor (3.93 crop factor) at its widest focal length and 1/4.5" at it's narrowest, with an f/2.2 lens, which means a relatively small ~3mm aperture which will necessarily yield muddy pictures, similar to most point-and-shoots?
Near? I've seen multi-megabyte.
Meters - not feet. 10GBaseT is good for 55 meters on Cat6 and 100 meters on Cat6A.
Before NK started on developing actual nukes, their "nuclear option" was (and very arguably still is) artillery pieces. Thousands of them, including a few hundred 170mm guns and 240mm rocket launchers that can potentially reach Seoul. North Korea has stated that they can rain 250,000 shells per hour down on Seoul, although South Korean estimates are that they can do, at best, 20,000, and more realistically 2,400.
Some big caveats to this:
In North America, residential power is "split-phase" which is still considered single phase - it is a pair of hot wires delivered to you, with neutral off the center tap of the transformer on the pole, tied to ground at the service entrance. It's actually very rare for just one of those phases to die (I have yet to see it happen), as it would require a break in one of the hot wires running from your house to the pole. These are low voltage lines so they are typically bundled together, so if run aerially, a tree would snag both of them at once, and if underground a flood would damage both at once. A dead transformer or a dead power line anywhere upstream of the transformer would kill power to both.
Three-phase failure modes often leave you with only one phase out of three working, but never two. This is regardless of whether you are drawing phase-to-neutral power or phase-to-phase power. Imagine the phases of a three-phase system as three dots in a triangle, and the connections between those dots are the power you can draw. If one of the dots goes away, you're left with just one remaining connection between the remaining pair of dots. Remember the neutral is only generated locally at the transformer, so it does not provide any sort of redundant path for anything outside of the building.
Not in the last 7-8 years it hasn't. I tried for 3 hours on the phone to get a laptop hard drive replaced under next-business-day warranty. They wouldn't budge, because I couldn't produce the output of the diagnostic tools that were loaded *on that hard drive*. In the end, we got the replacement drive when they felt they could get around to it.
These days, there's little point to getting a hot-swap RAID server from Dell, because to get a replacement drive from them they will ask you to take the server offline and run the diagnostic checks on it. This is a far cry from 10+ years ago when I got replacement drives via UPS SonicAir over holiday weekends.
What do you think explains the jurisdiction shopping that lead to a large increase of these cases being pursued in East Texas?
Another way to calculate this: Google "c/1.8GHz" and it'll give you the result in centimeters. Then just divide by two to get a half-wavelength dipole or divide by 4 to get a 1/4-wave ground plane length.
If you want a high-gain directional antenna for >1GHz you're probably best off with a dish, perhaps using a cantenna-like feed horn.
Or a small scale-model wind tunnel that could cheaply and easily be built with some plywood, some fans, and maybe some smoke or thread to show wind direction. It shouldn't cost more than $100.
You sound like you have something to prove here. Get on it.
No, it is not. Split-phase is the norm.
It's been done. Here's one. There are few others out there too.
90% for both generator and battery charge/discharge combined is reasonable, since you *will* be operating at the motor's peak efficiency there.
Now, to properly compare apples to apples, look at this graph (on page 10) regarding the Prius motor's efficiency at various power outputs (you've probably already seen this since you mentioned it earlier). Below 5kW, it's at 25%. At 10kW, it's at 33%, and that's a realistic highway speed power output. If we can assume 33%*90% (drivetrain) we get 29.7% - with a 38% Stirling engine, if we get 90% from the rest of the system (generator, battery, controller, wiring) - and I've already posted links showing that's do-able - then if your motor exceeds 87% efficiency you come out ahead. At 5kW output you just need 67% motor efficiency to come out ahead. It's nearly a wash, plus there's lots of tricks you can pull with electric motors when you have a handful of them (vs just one engine).
Google for 'brushless dc ev' and you'll find lots and lots of product hits.
"Back in the 1990s all of the electric vehicles except one were powered by DC brushless drives. Today, all the hybrids are powered by DC brushless drives, with no exceptions. The only notable uses of induction drives have been the General Motors EV-1; the AC Propulsion vehicles, including the tzero; and the Tesla Roadster." (Granted this is from 2007 but still a good article on the differences between the two types.)
It's not theoretical best case when it's already been done, and I was not cherry picking numbers. Here's some that are closer to the state of the art, for comparison: A 99% efficient BLDC controller - most of the controller inefficiencies are from band-gap voltage drop, which gets smaller as you use higher voltages (as does resistive losses in the wiring). Here's a 98% efficient motor, used on the CSIRO-UTS solar racer..
Are you really claiming that (for example) a modern 50kW motor would shed 5kW heat? Mid-90s efficiency is typical today for larger motors - it is not a cherry-picked exception!
90% is too conservative. Brushless DC motors (the sort you'd pair with a VFD in any electric car) are pushing 96%: http://www.ti.com/ww/en/motor_drive_and_control_solutions/motor_control_type_brushless_dc_BLDC.htm. Lithium Ion battery efficiency is, depending on your source, 95% or 97-99%. So your 27% figure could be 34%. More importantly, since you have a drivetrain capable of driving the car at highway speeds in pure electric mode (something current parallel hybrids lack), a series hybrid could potentially be cheaper to operate if charged at night, and you can recoup more energy through regenerative braking.