Duh. (Atomic # of Cu + atomic # of Sn) / 2. You forgot to include the typical 88% Cu, 12% Sn ratio, so the real answer would be more like 0.88 * 29 + 0.12 * 50 = 31.52.
I am not a lawyer, but IMHO no private entity that is not a creditor is "required by law" to accept dollars as payment, either physically as actual notes or as the unit of a promissory note (check). It would be business suicide for a US store to _not_ accept them, but there's plenty of precedent for businesses not accepting physical notes, and pure barter is still quite legal.
Note that I said creditor - the rule of 'all DEBTS public and private' comes in to play when there's a debt owed. Attempting to buy something does not create a debt, so that rule does not apply. Eating in a restaurant that collects payment after the meal DOES create a debt, therefore they must accept currency as payment.
The typical failure mode in an ice storm is not downed trees breaking the power lines, but ice-laden branches bending down and shorting the power line to ground (most often pine trees around central Virginia). This rarely has an effect on phone lines since they're insulated (no danger of shorts) and are very well supported by a steel cable (can handle the extra weight).
I live roughly 100 miles from Washington DC just outside of Richmond, VA
So do I. Small world. I had a similar experience. I lost commercial power for a week along with internet service, cell service, and cu-based phone service. I have a whole-house generator, so I was ok until the coup de grace - a tree fell on my satellite dish and crushed it!
Where do you live, approx? Drop me a line at dtiller0112 at david[nospam]tiller dot com.
A lot of people on Slashdot don't seem to understand how radiation affects the body. Radiation from outside the body isn't too much of a problem because the skin acts as a barrier and it will be washed away fairly quickly.
You must distinguish between sources ON the skin vs sources in the environment (both of which are outside the body).
The skin provides decent protection only against alpha particles. Beta radiation penetrates skin (they use it for radiotherapy), and gamma goes very deep indeed - sometimes right through.
The skin does not help against beta or gamma emitters on the skin or in the environment. All emitters in the environment pose an ingestion hazard as you said, but the free mean path of an alpha is so short it's unlikely to get any significant exposure thru the air.
"The regulations are being issued in the form of an interim rule, to be effective for a period of 120 days from the time of publication. The interim rule states that during a 30-day period from the date of publication, the public can submit written comments to the United States Mint on the regulations. Upon consideration of such comments, the Director of the United States Mint would then issue the final rule. "
The interim part is with regard to soliciting comments, not the final duration of the law. Note that it says the Director of the Mint will issue a final ruling - he did, and it was published in the Federal Register and it's in effect until repealed.
Both large and small reactors have their uses, but AFAIK the small ones are likely to be less efficient and produce more waste* per kWh. I applaud the renaissance of 'modern' reactor construction to help wean us off the petro-teat, but am sorely disappointed that we're still burning less than 1% of the available energy in our current nuclear fuel and calling the other 99% 'waste'. Integralfast reactors should be a part of (if not the future of) the world's energy production.
*Not necessarily waste from the fuel itself, but more incidental waste like cladding storage containers, contaminated clothing, etc.
Not exactly a vending machine, but the automated toll collectors on the RMA in Richmond VA do accept pennies. They have a sign that says "No pennies please", but they do work. They just take forever for the machine to count fill up the change bin quickly.
Interesting fact: you can tell the difference between a mostly-Cu penny and a mostly-Zn penny by sound. Dropping a Cu penny on a hard surface results in a high-pitched 'ting' - the Zn penny makes more of a 'thunk' sound.
I wouldn't say the idea of "The Man" tracking us has been put to bed. Who would've thought there'd be thousands of CCTV cameras deployed in London? They are/were expensive, fragile, and need lots of bandwidth. That didn't stop a gov't with a nearly unlimited budget and a penchant for snooping.
Tracking humans as they walk along a street with RFID tags in their clothes? Easy, since a single read from a 'registered' garment will suffice to ID the wearer. Extra reads are gravy. Garments are most often on the outside of the 'ugly bag of mostly water', so attenuation isn't a big deal. The distances involved are very short, and the gov't doesn't have to worry about stealth wrt reader placement. You know gov'ts are deploying RFID readers at borders to track cars by the now-required RFID tag in tires, right?
As for the ZigBee solution: I can't predict prices. ZigBee is in that precarious Ouroboros loop of "there-are-too-few-adopters-beacuse-it's-expensive-but-it-would-be-cheaper-if-there-were-more-adopters". That sort of thought pattern is what blew Norman's circuit breaker.
If you're going for a full-on product, then yes, you'll need those things. If you're hacking together something, then quite literally a few soldered on wires and either a thermistor or solid state temp sensor would do. We're talking an extra $2 or so.
Alternatively you could go with a different chipset. There are 'naked' ZigBee chips out there if development costs are less important than unit cost. You can get the chipset used in the digi modules; also Microchiphas a few solutions, but you'll pay dearly to license the ZigBee stack, and be doing some serious low-level hacking.
Another solution if you don't require actual ZigBee interoperability: go with straight 802.15.4 and a simpler, cheaper protocol on top of it. There's MIWI, digimesh, plus a whole host of others.
Good luck with your project - you seem quite passionate about it.
In the US much of the agriculture happens in flyover country. These areas probably don't have that much sewage. Sure, they have it, but you need a LOT of water to irrigate a field.
They don't have much _human_ sewage. The amount of farm animal sewage that's generated is staggering. it's also generally produced close to plant-producing farms.
Let's be clear - the FCC is not in the business of validating that any particular device is generally well-made or robustly-designed. Their one and only concern wrt to type acceptance is the RF _emissions_ of the device. They do not require testing of receivers for susceptibility to nearby carriers, intermodulation, desense or anything else, only their (in the case of a receiver, unintentional-) emissions. All not-otherwise licensed equipment carries the all-too familiar Part 15 warning about not causing and having to accept interference.
For a non battery-assisted tag at 30m through free space with a non-pinpoint beam antenna* you'd be hard-pressed to get 10% [yes, 10%] read for a tag that's < $1 and small. At 100m, no chance. I hate to say it, but I think your idea of RFID as a sensor net is DOA both from the physics involved and the expense (RFID readers/antennas/coax/etc are not cheap).
Look up the power link budget of RFID - the fact that they work at all is astonishing. The power that the RFID reader gets back from the tag falls off as the 4th power of distance - that a wicked barrier. Add to that the directivity issues, and you're talking impossible.
* To read tags scattered across a building, you need omnidirectional antennas, or at least a small number of moderately directional antennas. This, however, is diametrically opposed to the need to read tags at a distance - the more power you focus into a beam, the less there is for reading tags outside the beam.
ZigBee modules are currently $22.50 for the SMT version and $17 for the DIP version. These are essentially small sensor platforms ready to go. They have a UART on board (their interface to the non-RF world is via the serial interface - you can use them to transfer RS-232 data from any device). They have A/D converters and digital IO lines on board, and can be configured to sleep, wake up, take readings, send data to the 'mother ship' (which is just another ZigBee module - no expensive reader needed) and go back to sleep. They can operate off of small batteries (3-ish volts, rx & tx current about 40 mA, sleep current in the microamp region). This is exactly what you want, with the added ability to use always-on nodes as mesh repeaters as well as sensor nodes. Suddenly your ZigBee-enabled lightswitch (that's mains-powered) is acting as a repeater for your solar powered swimming pool wave height sensor - with NO explicit configuration! They even have a USB stick version that appears as a standard COM port to your computer.
PLEASE have a look at the Digi zigbee modules - they're extremely well thought out, and have lots of features in a small, efficient package.
PS - They have higher power ones and have ones with antenna connectors if you want even more flexibility. They have data collectors/routers as ready-to-go products that can publish to the web and be managed over the web if you don't want to roll your own.
'The Fifth Element'-esque sleepy-time travel chambers didn't seem to be anesthetic-based to me; they seemed more electronic. The flight attendant flipped a switch and Corbin Dallas dropped like a poled Ox.
I worked on a project some time ago that studied the feasibility of using RFID tags in a whole host of industrial and commercial settings. Our findings where that many of the use cases that RFID was expected to solve were not possible to the level of reliability that most customers expected. I can't go into details of the customers, but one scenario was attempting to track goods on a pallet. Each item on the pallet would have a tag and as the pallet was picked up by a reader-enabled forklift, all of the tagged items were read and validated against the shipping manifest. It worked well for dry goods, but we found it impossible to read the inner tags on pallets with frozen turkeys or ice cream. Pesky RF absorption! The interim solution was to use a pallet tag that referenced the items on the manifest.
Similarly we were called on to read tags on very high value large goods as they passed under a portal on a truck bed. The issues there were twofold - the items were steel (not conducive to having an RF tag work when applied to it), and the antennas has to be above the lane and high enough for a semi trailer to pass under. That stooged up the read range. This scenario worked fairly well, but we still had missed reads depending on geometry and tag placement. Plus metal-compatible tags were savagely expensive (but reasonable considering the cost of the items they were on - we're talking $100k - $2M+ items).
I have other stories, but all of them end up with "It works, most of the time. If you want 100% reads, use another technology."
Notice that even the mighty Walmart backed WAY off on their mandatory RFID tagging requirements and their smart-shelf technology. It simply isn't reliable enough right now.
PS - I've also used ZigBee on some of my personal, hobby projects. I like the Digi modules - I've designed a mesh of solar-powered sensors using Digi ZigBee modules and Microchip PIC microcontrollers. Very fun.
Have you ever worked with RFID readers? it's fantastically difficult to get them to work under optimal conditions, much less having the reader far enough away from the tags to make it worth not using wires or powered sensors. Add to the equation powering a sensor from an RF field (limited to 4W EIRP at 908-928 MHz) and you're pretty much doomed.
Our dogs _love_ green beans - so much that you can't even say the word 'green' without them jumping up and down with excitement. They get them on their kibble every night. They also adore carrots - can't say that word around them, either.
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My guess is that he meant 'elegant'.
Yeah, it's called the Voight Kampff test. They'll just make a Nexus 7 shill that can beat the test.
Duh. (Atomic # of Cu + atomic # of Sn) / 2. You forgot to include the typical 88% Cu, 12% Sn ratio, so the real answer would be more like 0.88 * 29 + 0.12 * 50 = 31.52.
I am not a lawyer, but IMHO no private entity that is not a creditor is "required by law" to accept dollars as payment, either physically as actual notes or as the unit of a promissory note (check). It would be business suicide for a US store to _not_ accept them, but there's plenty of precedent for businesses not accepting physical notes, and pure barter is still quite legal.
Note that I said creditor - the rule of 'all DEBTS public and private' comes in to play when there's a debt owed. Attempting to buy something does not create a debt, so that rule does not apply. Eating in a restaurant that collects payment after the meal DOES create a debt, therefore they must accept currency as payment.
This article has a good discussion.
This guy gets it close, but confuses creditor with seller.
Something tells me you don't mean Freeman Dyson.
What does that vacuum cleaner dude have to do with any of this?
The typical failure mode in an ice storm is not downed trees breaking the power lines, but ice-laden branches bending down and shorting the power line to ground (most often pine trees around central Virginia). This rarely has an effect on phone lines since they're insulated (no danger of shorts) and are very well supported by a steel cable (can handle the extra weight).
I live roughly 100 miles from Washington DC just outside of Richmond, VA
So do I. Small world. I had a similar experience. I lost commercial power for a week along with internet service, cell service, and cu-based phone service. I have a whole-house generator, so I was ok until the coup de grace - a tree fell on my satellite dish and crushed it!
Where do you live, approx? Drop me a line at dtiller0112 at david[nospam]tiller dot com.
Oxygen.
A lot of people on Slashdot don't seem to understand how radiation affects the body. Radiation from outside the body isn't too much of a problem because the skin acts as a barrier and it will be washed away fairly quickly.
You must distinguish between sources ON the skin vs sources in the environment (both of which are outside the body).
The skin provides decent protection only against alpha particles. Beta radiation penetrates skin (they use it for radiotherapy), and gamma goes very deep indeed - sometimes right through.
The skin does not help against beta or gamma emitters on the skin or in the environment. All emitters in the environment pose an ingestion hazard as you said, but the free mean path of an alpha is so short it's unlikely to get any significant exposure thru the air.
Well I would take one in my back yard for free power.
The things people will do for free power! Oh, you meant a _power plant_ in your actual back yard....nevermind.
If you read the whole comment, it says:
"The regulations are being issued in the form of an interim rule, to be effective for a period of 120 days from the time of publication. The interim rule states that during a 30-day period from the date of publication, the public can submit written comments to the United States Mint on the regulations. Upon consideration of such comments, the Director of the United States Mint would then issue the final rule. "
The interim part is with regard to soliciting comments, not the final duration of the law. Note that it says the Director of the Mint will issue a final ruling - he did, and it was published in the Federal Register and it's in effect until repealed.
Both large and small reactors have their uses, but AFAIK the small ones are likely to be less efficient and produce more waste* per kWh. I applaud the renaissance of 'modern' reactor construction to help wean us off the petro-teat, but am sorely disappointed that we're still burning less than 1% of the available energy in our current nuclear fuel and calling the other 99% 'waste'. Integral fast reactors should be a part of (if not the future of) the world's energy production.
*Not necessarily waste from the fuel itself, but more incidental waste like cladding storage containers, contaminated clothing, etc.
Not exactly a vending machine, but the automated toll collectors on the RMA in Richmond VA do accept pennies. They have a sign that says "No pennies please", but they do work. They just take forever for the machine to count fill up the change bin quickly.
Or an English half penny. Half Penny was often shortened (Cockney-ized?) to Ha'Penny [hay penny] as in the song Christmas is Coming.
What do you think a $5 bill is worth?
About 12.44 BTU theoretical, 4 BTU recoverable.
Sadly, it's now illegal to melt them down.
Interesting fact: you can tell the difference between a mostly-Cu penny and a mostly-Zn penny by sound. Dropping a Cu penny on a hard surface results in a high-pitched 'ting' - the Zn penny makes more of a 'thunk' sound.
I wouldn't say the idea of "The Man" tracking us has been put to bed. Who would've thought there'd be thousands of CCTV cameras deployed in London? They are/were expensive, fragile, and need lots of bandwidth. That didn't stop a gov't with a nearly unlimited budget and a penchant for snooping.
Tracking humans as they walk along a street with RFID tags in their clothes? Easy, since a single read from a 'registered' garment will suffice to ID the wearer. Extra reads are gravy. Garments are most often on the outside of the 'ugly bag of mostly water', so attenuation isn't a big deal. The distances involved are very short, and the gov't doesn't have to worry about stealth wrt reader placement. You know gov'ts are deploying RFID readers at borders to track cars by the now-required RFID tag in tires, right?
As for the ZigBee solution: I can't predict prices. ZigBee is in that precarious Ouroboros loop of "there-are-too-few-adopters-beacuse-it's-expensive-but-it-would-be-cheaper-if-there-were-more-adopters". That sort of thought pattern is what blew Norman's circuit breaker.
If you're going for a full-on product, then yes, you'll need those things. If you're hacking together something, then quite literally a few soldered on wires and either a thermistor or solid state temp sensor would do. We're talking an extra $2 or so.
Alternatively you could go with a different chipset. There are 'naked' ZigBee chips out there if development costs are less important than unit cost. You can get the chipset used in the digi modules; also Microchip has a few solutions, but you'll pay dearly to license the ZigBee stack, and be doing some serious low-level hacking.
Another solution if you don't require actual ZigBee interoperability: go with straight 802.15.4 and a simpler, cheaper protocol on top of it. There's MIWI, digimesh, plus a whole host of others.
Good luck with your project - you seem quite passionate about it.
In the US much of the agriculture happens in flyover country. These areas probably don't have that much sewage. Sure, they have it, but you need a LOT of water to irrigate a field.
They don't have much _human_ sewage. The amount of farm animal sewage that's generated is staggering. it's also generally produced close to plant-producing farms.
Let's be clear - the FCC is not in the business of validating that any particular device is generally well-made or robustly-designed. Their one and only concern wrt to type acceptance is the RF _emissions_ of the device. They do not require testing of receivers for susceptibility to nearby carriers, intermodulation, desense or anything else, only their (in the case of a receiver, unintentional-) emissions. All not-otherwise licensed equipment carries the all-too familiar Part 15 warning about not causing and having to accept interference.
For a non battery-assisted tag at 30m through free space with a non-pinpoint beam antenna* you'd be hard-pressed to get 10% [yes, 10%] read for a tag that's < $1 and small. At 100m, no chance. I hate to say it, but I think your idea of RFID as a sensor net is DOA both from the physics involved and the expense (RFID readers/antennas/coax/etc are not cheap).
Look up the power link budget of RFID - the fact that they work at all is astonishing. The power that the RFID reader gets back from the tag falls off as the 4th power of distance - that a wicked barrier. Add to that the directivity issues, and you're talking impossible.
* To read tags scattered across a building, you need omnidirectional antennas, or at least a small number of moderately directional antennas. This, however, is diametrically opposed to the need to read tags at a distance - the more power you focus into a beam, the less there is for reading tags outside the beam.
ZigBee modules are currently $22.50 for the SMT version and $17 for the DIP version. These are essentially small sensor platforms ready to go. They have a UART on board (their interface to the non-RF world is via the serial interface - you can use them to transfer RS-232 data from any device). They have A/D converters and digital IO lines on board, and can be configured to sleep, wake up, take readings, send data to the 'mother ship' (which is just another ZigBee module - no expensive reader needed) and go back to sleep. They can operate off of small batteries (3-ish volts, rx & tx current about 40 mA, sleep current in the microamp region). This is exactly what you want, with the added ability to use always-on nodes as mesh repeaters as well as sensor nodes. Suddenly your ZigBee-enabled lightswitch (that's mains-powered) is acting as a repeater for your solar powered swimming pool wave height sensor - with NO explicit configuration! They even have a USB stick version that appears as a standard COM port to your computer.
PLEASE have a look at the Digi zigbee modules - they're extremely well thought out, and have lots of features in a small, efficient package.
PS - They have higher power ones and have ones with antenna connectors if you want even more flexibility. They have data collectors/routers as ready-to-go products that can publish to the web and be managed over the web if you don't want to roll your own.
'The Fifth Element'-esque sleepy-time travel chambers didn't seem to be anesthetic-based to me; they seemed more electronic. The flight attendant flipped a switch and Corbin Dallas dropped like a poled Ox.
I worked on a project some time ago that studied the feasibility of using RFID tags in a whole host of industrial and commercial settings. Our findings where that many of the use cases that RFID was expected to solve were not possible to the level of reliability that most customers expected. I can't go into details of the customers, but one scenario was attempting to track goods on a pallet. Each item on the pallet would have a tag and as the pallet was picked up by a reader-enabled forklift, all of the tagged items were read and validated against the shipping manifest. It worked well for dry goods, but we found it impossible to read the inner tags on pallets with frozen turkeys or ice cream. Pesky RF absorption! The interim solution was to use a pallet tag that referenced the items on the manifest.
Similarly we were called on to read tags on very high value large goods as they passed under a portal on a truck bed. The issues there were twofold - the items were steel (not conducive to having an RF tag work when applied to it), and the antennas has to be above the lane and high enough for a semi trailer to pass under. That stooged up the read range. This scenario worked fairly well, but we still had missed reads depending on geometry and tag placement. Plus metal-compatible tags were savagely expensive (but reasonable considering the cost of the items they were on - we're talking $100k - $2M+ items).
I have other stories, but all of them end up with "It works, most of the time. If you want 100% reads, use another technology."
Notice that even the mighty Walmart backed WAY off on their mandatory RFID tagging requirements and their smart-shelf technology. It simply isn't reliable enough right now.
PS - I've also used ZigBee on some of my personal, hobby projects. I like the Digi modules - I've designed a mesh of solar-powered sensors using Digi ZigBee modules and Microchip PIC microcontrollers. Very fun.
Have you ever worked with RFID readers? it's fantastically difficult to get them to work under optimal conditions, much less having the reader far enough away from the tags to make it worth not using wires or powered sensors. Add to the equation powering a sensor from an RF field (limited to 4W EIRP at 908-928 MHz) and you're pretty much doomed.
http://www.enigmatic-consulting.com/Communications_articles/RFID/Link_budgets.html
Our dogs _love_ green beans - so much that you can't even say the word 'green' without them jumping up and down with excitement. They get them on their kibble every night. They also adore carrots - can't say that word around them, either.
Hydrazine isn't used for heavy lifting rockets.
I'm not sure if you consider the Titan II,III, and IV series 'heavy lift' (I think you should), but they used a UDMH/hydrazine mix and nitrogen tetroxide and flew as recently as 2005.