There sure seems to be a lot of variance in published OC voltages, I agree. It's handy to know the no-load OC voltage of batteries (so that you can spec other components in the system), but as you state it would also be interesting to know the V/I curve. Most manufacturers actually do publish that sortof data.
They're named the way they are because of their chemistry. An alkaline cell has an open circuit voltage of 1.43V - close enough to the old Zinc-Carbon cell's OC voltage of 1.5V. A lead-acid cell has an open circuit voltage of about 2.1V. 6 of those in series makes 12-ish V. The cell potential between the anode and cathode materials determines their open circuit voltage (see this chart).
The article states that the voltage of the LiS cell is 'about half' the voltage of a Li-ion, so that's about 2V/cell. You'd need at least 6* to make 12V, so that means a 12V, 30Ah battery would consist of 25 parallel sets of 7 cells in series and weigh in at 175g, or about 6 ounces - quite a weight savings.
*"12V" isn't really 12V exactly. It's more like 13.8 under charge and as low as 10.5-11 at discharge. Most gizmos expect the voltage toward the higher end, so using 7 cells isn't uncommon among DIY-ers (It allows you to use your devices longer with the battery still in the higher voltage sweet spot).
I'd rather see the 'internet' provide ATM access as opposed to IP. ATM provides circuits with guaranteed latency and jitter levels for time-critical uses such as telephony, game playing, video, etc.
The following is from Ted Molczan, an expert on satellites and launches and a major contributor to the seesat-l list. There's a good change of seeing a fuel dump from a Delta 4 medium if you're in the right place at the right time.
WGS 5 is scheduled for launch from Cape Canaveral on a Delta 4 Medium+(5,4) in about 11 hours, on 2013 May 24, between 00:27 and 00:57 UTC. http://www.spaceflightnow.com/delta/d362/status.html I offer the following rough TLE of the orbit after the final burn of the 2nd stage, assuming launch at window-open: SECO-2 440 X 66991 km 1 78901U 13144.04069444.00000000 00000-0 00000-0 0 02 2 78901 24.0048 67.6288 8299446 177.8402 1.4113 1.08160032 04 Following spacecraft separation, observers within range should look for the following 2nd stage events (times approximate):
T+ UTC 00:45:00 01:12:00 CCAM Start (Collision and Contamination Avoidance Manoeuvre) 00:47:20 01:14:20 CCAM End 00:54:41 01:21:41 H2 Depletion End 00:56:40 01:23:40 O2 Depletion End 01:18:33 01:45:33 N2H4 depletion End
The fuel dump could produce a spectacular comet-like phenomenon, similar to that of WGS 4, imaged last year despite challenging conditions by Willie Koorts: http://satobs.org/seesat/Jan-2012/0270.html
The following is from Ted Molczan, an expert on satellites and launches and a major contributor to the seesat-l list. There's a good change of seeing a fuel dump from a Delta 4 medium if you're in the right place at the right time.
WGS 5 is scheduled for launch from Cape Canaveral on a Delta 4 Medium+(5,4) in about 11 hours, on 2013 May 24, between 00:27 and 00:57 UTC. http://www.spaceflightnow.com/delta/d362/status.html I offer the following rough TLE of the orbit after the final burn of the 2nd stage, assuming launch at window-open: SECO-2 440 X 66991 km 1 78901U 13144.04069444.00000000 00000-0 00000-0 0 02 2 78901 24.0048 67.6288 8299446 177.8402 1.4113 1.08160032 04 Following spacecraft separation, observers within range should look for the following 2nd stage events (times approximate):
T+ UTC 00:45:00 01:12:00 CCAM Start (Collision and Contamination Avoidance Manoeuvre) 00:47:20 01:14:20 CCAM End 00:54:41 01:21:41 H2 Depletion End 00:56:40 01:23:40 O2 Depletion End 01:18:33 01:45:33 N2H4 depletion End
The fuel dump could produce a spectacular comet-like phenomenon, similar to that of WGS 4, imaged last year despite challenging conditions by Willie Koorts: http://satobs.org/seesat/Jan-2012/0270.html
Almost no-one knows nothing about guns. They may not know as much as you'd like, but most people know something.
Sadly it seems most of this firearm 'knowledge' is obtained from watching movies, not from taking a safety course and heading down to the range. Most of what they 'know' is more like what they think they know to be true.
What about a mechanism that disables the gun if it detects that an unauthorized person is trying to use it?
I came here to say exactly this. I'd put my children's and all their friends prints in the 'do not fire' category as an added layer of defense against them getting access to one of my firearms until they're of an age to safely and responsibly handle a weapon.
"An adult human body contains about 160 grams of potassium, hence about 0.000117 x 160 = 0.0187 grams of 40K; whose decay produces about 4,400 disintegrations per second (becquerels) continuously throughout the life of the body."
Designing a microwave link below 50 GHz where the path loss is at most 0.2 dB/km is MUCH easier than designing one that can range from 3dB/km to 40dB/km. For every km of path, 37dB of dynamic range/headroom is a factor of around 5000x (closer to 5012, actually). If you need 1W to achieve your desired S/N ratio in dry air (3dB loss) over 1 km, you'll need 5kW when it's raining. Make that 2 km and you go from needing 2W (6dB loss) to needing 50 MW (yes, megawatts at 80dB loss).
Even if the required signal levels are 3 orders of magnitude lower (i.e. 1mW will work over 1 km of dry air) you will still need ridiculous amounts of power past a few km. Even at 2 km you're looking at 50kW at 80dB/2 km.
We haven't even considered the reflectivity/opacity of leaves/plants/etc if you're proposing this for "last mile" use. You'll need a very clear line-of-sight path for this.
This band is not useful for long haul carriage due to atmospheric water vapor absorption. According to this chart, absorption between 200 and 280 GHz varies between 3 and 40 dB/km. That means at the low end only 50% of your signal is absorbed every km. At the high end, only 1/10,000th of your signal remains after each km.
this post speaks to similar issues including refraction.
Germination rates in the area of our facility with wireless access are roughly half of that on the other side of the shed...
There are other variables involved, like whether the sun shines more on one side of the shed (raising the temperature on that side), whether the door is nearer one side or the other, etc. Without validating the other scenarios (no wifi anywhere = germination everywhere; wifi on the other side = swapped germination; wifi on both sides = no germination), your 'data' is nothing more than a coincidence.
As an amateur radio operator I regularly deal with MUCH higher power levels at similar frequencies* - I have never seen any such result, so my 'data' offsets yours.
*We are allowed to transmit with up to 1500W PEP in the same band as Wifi, namely 2300-2450MHz (with gaps). There are no limits to the gain of the antennas we use, so we could easily have an EIRP in the 10's of megawatts. I can legally run a microwave oven with the door open.
In addition to all of the other comments, the liquid may well be acting as a neutron moderator, preventing criticality in the solid. These tanks are _very_ dangerous - some are right on the edge of criticality and must be stirred and some must be cooled to prevent self-boiling.
Check out the Banana-equivalent dose. Bananas and other high potassium foods are naturally radioactive. Brazil nuts are not only high in Na "... but also radium [and] may have up to 444 Bq/kg" - that's a third of the limit from naturally occurring radiation in food.
Your body's natural Na undergoes 5400 decays every second of your life.
Moving it would be as dangerous as piping it around. I read the reports from Hanford, and it's an unholy mess. They have tanks that hold a million+ gallons of 'stuff' - stuff that NO ONE knows the recipe for. They have tanks that self-heat to boiling, and tanks that require stirring to prevent criticality events.
It would be a much better proposition, IMHO, to vitrify the waste in place in the tanks, perhaps by cutting off the tank's top, dumping sand into the tanks, lowering in the 'trodes, and zapping the layer on the bottom into glass. Repeat until solid. I'm sure that there's a way to put a temporary barrier in place in the tank if needed as insulation while vitrifying.
... liquid salt and/or sodium remain possibilities (though the corrosive effects of molten sodium on a whole host of piping make using it as a heat exchange fluid a challenging engineering problem. That, and if it should ever cool, i.e. freeze, remelting it is going to be a solid gold nightmare.) We won't even discuss the problems involving a red hot sodium leak into a second stage steam turbine system.
So don't use Sodium, use FLiBe in a Thorium fast reactor. A LFTR. They are quite a bit safer intrinsically than current reactors are with all their safety systems designed in. As a plus, you don't need water at all for a LFTR (secondary coolant can be helium or other working fluid) - you can build them anywhere, not just near a body of water. Please watch this video it's a great intro to LFTR's and why they're so different than existing PWRs.
Funny - that was another proposal* I made years ago in reference to data-to-the-premises as well as cell towers and radio stations (and power transmission, etc). I wanted to create what I called a '10% company' that had a specific charter to provide connectivity - nothing else - with a guarantee of 10% profit. Any provider could hook into the service for the same yearly fee as any other, leveling the playing field for small telcos/radio stations/etc.
The benefits would be huge especially for data-to-the-premises and cell phones - one strand of fiber to the home for phone, internet, and video regardless of what service you subscribed to. Minimization of cell towers (no more stacks of antennas per cell tower or multiple towers/site) - all of the connectivity would be the same (nationally-mandated) protocol, and all phones could automatically interconnect with any provider. Same idea w/ radio station towers, etc. All the transmitters and antennas could be co-located, or even better, merged into 1 wideband transmitter with all the signals muxed into it.
Ah, my dream from the late 80's surfaces again. I proposed this exact model a long time ago using ATM. With bandwidth, jitter, and latency guarantees ATM is the perfect protocol for audio and video (and the ultimate setup for low-latency gaming!). I said then (and still believe) that I'd rather have 5 ATM channels that I can connect to any video source I choose than 500 of what the cable company wants me to see. Why shouldn't I be able to see Portland Oregon's evening news? Why shouldn't I be able to take a peek at the local stations in George Town, Grand Cayman?
Slashdot Mirror
There sure seems to be a lot of variance in published OC voltages, I agree. It's handy to know the no-load OC voltage of batteries (so that you can spec other components in the system), but as you state it would also be interesting to know the V/I curve. Most manufacturers actually do publish that sort of data.
They're named the way they are because of their chemistry. An alkaline cell has an open circuit voltage of 1.43V - close enough to the old Zinc-Carbon cell's OC voltage of 1.5V. A lead-acid cell has an open circuit voltage of about 2.1V. 6 of those in series makes 12-ish V. The cell potential between the anode and cathode materials determines their open circuit voltage (see this chart).
Here's a great FAQ on battery chemistries.
The article states that the voltage of the LiS cell is 'about half' the voltage of a Li-ion, so that's about 2V/cell. You'd need at least 6* to make 12V, so that means a 12V, 30Ah battery would consist of 25 parallel sets of 7 cells in series and weigh in at 175g, or about 6 ounces - quite a weight savings.
*"12V" isn't really 12V exactly. It's more like 13.8 under charge and as low as 10.5-11 at discharge. Most gizmos expect the voltage toward the higher end, so using 7 cells isn't uncommon among DIY-ers (It allows you to use your devices longer with the battery still in the higher voltage sweet spot).
I'd rather see the 'internet' provide ATM access as opposed to IP. ATM provides circuits with guaranteed latency and jitter levels for time-critical uses such as telephony, game playing, video, etc.
Whoosh!
Protip: Don't use 'protip' - you sound like a pompous ass.
1982-ish and previous pennies were 97.5% copper. You can tell the difference by the sound they make when dropped on a hard surface.
The following is from Ted Molczan, an expert on satellites and launches and a major contributor to the seesat-l list. There's a good change of seeing a fuel dump from a Delta 4 medium if you're in the right place at the right time.
The following is from Ted Molczan, an expert on satellites and launches and a major contributor to the seesat-l list. There's a good change of seeing a fuel dump from a Delta 4 medium if you're in the right place at the right time.
Almost no-one knows nothing about guns. They may not know as much as you'd like, but most people know something.
Sadly it seems most of this firearm 'knowledge' is obtained from watching movies, not from taking a safety course and heading down to the range. Most of what they 'know' is more like what they think they know to be true.
What about a mechanism that disables the gun if it detects that an unauthorized person is trying to use it?
I came here to say exactly this. I'd put my children's and all their friends prints in the 'do not fire' category as an added layer of defense against them getting access to one of my firearms until they're of an age to safely and responsibly handle a weapon.
Buy a shaker of "no-salt" (KCl)
You realize that the K40 in that no-salt is already radioactive, right? From the article:
"An adult human body contains about 160 grams of potassium, hence about 0.000117 x 160 = 0.0187 grams of 40K; whose decay produces about 4,400 disintegrations per second (becquerels) continuously throughout the life of the body."
Designing a microwave link below 50 GHz where the path loss is at most 0.2 dB/km is MUCH easier than designing one that can range from 3dB/km to 40dB/km. For every km of path, 37dB of dynamic range/headroom is a factor of around 5000x (closer to 5012, actually). If you need 1W to achieve your desired S/N ratio in dry air (3dB loss) over 1 km, you'll need 5kW when it's raining. Make that 2 km and you go from needing 2W (6dB loss) to needing 50 MW (yes, megawatts at 80dB loss).
Even if the required signal levels are 3 orders of magnitude lower (i.e. 1mW will work over 1 km of dry air) you will still need ridiculous amounts of power past a few km. Even at 2 km you're looking at 50kW at 80dB/2 km.
We haven't even considered the reflectivity/opacity of leaves/plants/etc if you're proposing this for "last mile" use. You'll need a very clear line-of-sight path for this.
Also, washing with alcohol would likely be as effective or possibly more so, but the downside is dryness.
Can you say Hand Sanitizer? 60-85% alcohol, typically.
I can never find organic irradiated ground meat.
Easy - grind your own! Buy the cut(s) of beef you like, and grind away!
This band is not useful for long haul carriage due to atmospheric water vapor absorption. According to this chart, absorption between 200 and 280 GHz varies between 3 and 40 dB/km. That means at the low end only 50% of your signal is absorbed every km. At the high end, only 1/10,000th of your signal remains after each km.
this post speaks to similar issues including refraction.
Germination rates in the area of our facility with wireless access are roughly half of that on the other side of the shed...
There are other variables involved, like whether the sun shines more on one side of the shed (raising the temperature on that side), whether the door is nearer one side or the other, etc. Without validating the other scenarios (no wifi anywhere = germination everywhere; wifi on the other side = swapped germination; wifi on both sides = no germination), your 'data' is nothing more than a coincidence.
As an amateur radio operator I regularly deal with MUCH higher power levels at similar frequencies* - I have never seen any such result, so my 'data' offsets yours.
*We are allowed to transmit with up to 1500W PEP in the same band as Wifi, namely 2300-2450MHz (with gaps). There are no limits to the gain of the antennas we use, so we could easily have an EIRP in the 10's of megawatts. I can legally run a microwave oven with the door open.
In addition to all of the other comments, the liquid may well be acting as a neutron moderator, preventing criticality in the solid. These tanks are _very_ dangerous - some are right on the edge of criticality and must be stirred and some must be cooled to prevent self-boiling.
Check out the Banana-equivalent dose. Bananas and other high potassium foods are naturally radioactive. Brazil nuts are not only high in Na "... but also radium [and] may have up to 444 Bq/kg" - that's a third of the limit from naturally occurring radiation in food.
Your body's natural Na undergoes 5400 decays every second of your life.
PS - perhaps add enough of that nasty polymer absorptive stuff to stop further mixing/movement before vitrification-in-place?
Moving it would be as dangerous as piping it around. I read the reports from Hanford, and it's an unholy mess. They have tanks that hold a million+ gallons of 'stuff' - stuff that NO ONE knows the recipe for. They have tanks that self-heat to boiling, and tanks that require stirring to prevent criticality events.
It would be a much better proposition, IMHO, to vitrify the waste in place in the tanks, perhaps by cutting off the tank's top, dumping sand into the tanks, lowering in the 'trodes, and zapping the layer on the bottom into glass. Repeat until solid. I'm sure that there's a way to put a temporary barrier in place in the tank if needed as insulation while vitrifying.
... liquid salt and/or sodium remain possibilities (though the corrosive effects of molten sodium on a whole host of piping make using it as a heat exchange fluid a challenging engineering problem. That, and if it should ever cool, i.e. freeze, remelting it is going to be a solid gold nightmare.) We won't even discuss the problems involving a red hot sodium leak into a second stage steam turbine system.
So don't use Sodium, use FLiBe in a Thorium fast reactor. A LFTR. They are quite a bit safer intrinsically than current reactors are with all their safety systems designed in. As a plus, you don't need water at all for a LFTR (secondary coolant can be helium or other working fluid) - you can build them anywhere, not just near a body of water. Please watch this video it's a great intro to LFTR's and why they're so different than existing PWRs.
Funny - that was another proposal* I made years ago in reference to data-to-the-premises as well as cell towers and radio stations (and power transmission, etc). I wanted to create what I called a '10% company' that had a specific charter to provide connectivity - nothing else - with a guarantee of 10% profit. Any provider could hook into the service for the same yearly fee as any other, leveling the playing field for small telcos/radio stations/etc.
The benefits would be huge especially for data-to-the-premises and cell phones - one strand of fiber to the home for phone, internet, and video regardless of what service you subscribed to. Minimization of cell towers (no more stacks of antennas per cell tower or multiple towers/site) - all of the connectivity would be the same (nationally-mandated) protocol, and all phones could automatically interconnect with any provider. Same idea w/ radio station towers, etc. All the transmitters and antennas could be co-located, or even better, merged into 1 wideband transmitter with all the signals muxed into it.
*The other proposal: http://entertainment.slashdot.org/comments.pl?sid=3737343&cid=43712211
Ah, my dream from the late 80's surfaces again. I proposed this exact model a long time ago using ATM. With bandwidth, jitter, and latency guarantees ATM is the perfect protocol for audio and video (and the ultimate setup for low-latency gaming!). I said then (and still believe) that I'd rather have 5 ATM channels that I can connect to any video source I choose than 500 of what the cable company wants me to see. Why shouldn't I be able to see Portland Oregon's evening news? Why shouldn't I be able to take a peek at the local stations in George Town, Grand Cayman?
Nixtamalization would have made that feed corn more useful to your digestive tract. If you ate plain corn exclusively you'd end up with pellegra.