This is completely incorrect. Lead has a *very* low fission cross section, and when it does produces little energy compared to actinide elements. It is primairly used as a neutron and xray reflector in bombs.
The largest bomb ever made, the Tsar bomb, had U238 in its casing for the original design and contributes half the explosive yield, or 25Mt of a total 50Mt. However because this also produces almost all the fallout it was replaced with lead (high z element for xray reflection, high mass as a tamper) for testing. This *reduced* the total yield to 25Mt. ie the lead contributes nothing.
The reason people think lead is the end result for fission is that many decay chains end at lead. But you have to wait a while.
Here's an example. Ehrlich's time was the 60s and 70s. Back then an American could work ONE JOB and OWN A HOME AND AFFORD TWO CARS AND A FAMILY.
I really have no idea where this comes from. But right now at least in NZ and Europe we are better off. My Daughter just moved out of home paying for everything herself with a part time Ikea job (she is still at school). She can afford a much nicer place (60m2) that when my generation moved out (which was nicer than when my parents moved out). Everything is cheaper in proportion to income by large margins. She laments she doesn't have much money and is poor because she can't afford a iPhone, laptop and 3 day concert tickets right *now*. Its going to take her a year or so to buy those "essential" items. Even appliances are much cheaper than ever before, a combination grill microwave is going for 50EU right now. Its just much cheaper in every respect. Hell my daughter is already planing two 2 week holidays in Croatia and France. Yea, really poor on a *part time job*. And yes, she pays for everything, i have not given her a penny.
Even for my wife and I, we spend less of our total income on rent/mortgage payments that my parents (less than half). Food is also really cheap in comparison, even with one income we can eat out many times a week. In short we have much more disposable income than 30-40 years ago.
Just look at commonly advertised products. Its no longer ovens or microwaves. Its luxury items that use disposable income, like smart phones and the like. Travel is so much cheaper these days that we don't really have the term "jet setter" anymore and just about everyone can afford tickets for international holidays more than once a lifetime. In the 60s and 70s you were lucky if you could afford it once in a lifetime! Now the current generation talks about OE (Overseas Experience) whcih is a fancy way of saying "bum around in another country".
Thing about the good ol' days is they weren't. You are not poor because you only have one car and a house/apartment with one toilet or can only afford a international holiday once every 2 years.
My router that my ISP sent me 4 years ago, is dual stack and it is enabled by default. My ISP does not support IPv6 however. But in my experience most hardware does have dual stack support.
Not correct. Protons and anti protons are not fundamental particles, but are made up of quarks. 2/3 of the energy is thus released as charged Pions moving at close to the speed of light. They would dump most of their energy into the surrounding matter before decaying. The other 1/3 of the energy will go into gammas (from a 0 pion decay intermediary) which does interact with the surrounding matter, but over longer ranges.
Long story short. You get something very similar to a normal nuke, without the neutrons and fallout.
The GM crops were made *sterile* to address the fears of the anti GM crowd that they would cross with non GM crops and contaminate the whole world!
If you had ever done any farming, you would know that you almost never ever keep "seed" from last years crop, you buy it cus it is so bloody cheap compared to everything else.
Nuclear fusion is getting closer. However it is tied up in the ITER boondoggle. Where most of the boondoggle has to do with politics rather than physics or engineering.
There are real physical limitations however. Even with perfect engines. Since lift is a reaction force we can calculate some BOTE figures. A lifting disk area of about 1m2 needs a downdraft velocity of 31 m/s for 1000N of thrust assuming a air density of 1kg/m3. That is 113km/h blast. The power required is 15.8kW (21hp) assuming a perfect engine to air coupling. This seems pretty reasonable. A pair of ducted fans need a diameter of about 80cm for a total disk area of 1 meter. Perhaps they can get a bit smaller!
Only thing is you have one problem. The "massively higher ISP" for jet engines (a stupid metric for a air breather) is because it collect's the Oxygen as it goes along with a bunch of Nitrogen. When you are traveling fast this cost a lot of energy or drag. This is the breakthrough they are hoping to get, but it would be a very big breakthrough, one that many aerospace engineers believe is fundamentally impossible. Also you have the other problem the the thrust to weight ratio of jet engines is awful compared to a rocket, about 10 vers 100. This eats your 30% before even starting. Finally there is costs, jet engines cost way more per kg (SSME not withstanding...). So its cheaper just to make a bigger tank (cheap), use more fuel+oxidizer(really cheap) and stick with rockets.
Despite everything, rockets are a real good match for the 9km/s deltaV needed for LEO. Planes don't look like trains, why do we insist that rockets should look like planes? They really do solve completely different problems.
Well i have had zero problems, and my window user friends didn't notice any missing features. In fact they were kinda surprised by how easily I added the web cam. Plug in out of the box, click on skypes setup thingy, web cam working. Several of my friends had to use the cams drivers to get it too work under windows.
YMMV but overall lately(5+years) I have been getting very very good mileage on my Linux installs.
I think you still don't quite get coherent in this context. For a femtosecond they may be 180 out of phase, then the next femtosecond its 129 deg since another photon with different phase is now also getting absorbed. Hence you just don't get a beat frequency. Each photon has a different and independent phase.
Yea, and then the news story posted to/. will be "Teacher takes cell phone off students" and about 90% of the/. comments will be outrage at the students rights getting violated.
depends on the source of hydrogen. In NZ natural gas (CNG) is pretty common for cars. However they are big heavy high pressure tanks that only give you about 300km range. Better than electric of course.
Slashdot Mirror
This is completely incorrect. Lead has a *very* low fission cross section, and when it does produces little energy compared to actinide elements. It is primairly used as a neutron and xray reflector in bombs.
The largest bomb ever made, the Tsar bomb, had U238 in its casing for the original design and contributes half the explosive yield, or 25Mt of a total 50Mt. However because this also produces almost all the fallout it was replaced with lead (high z element for xray reflection, high mass as a tamper) for testing. This *reduced* the total yield to 25Mt. ie the lead contributes nothing.
The reason people think lead is the end result for fission is that many decay chains end at lead. But you have to wait a while.
Try Iain Banks Culture series as to one persons interpretation of what life could be like in a "post scarcity" society.
"Money is a sign of poverty" -- Iain Banks.
Here's an example. Ehrlich's time was the 60s and 70s. Back then an American could work ONE JOB and OWN A HOME AND AFFORD TWO CARS AND A FAMILY.
I really have no idea where this comes from. But right now at least in NZ and Europe we are better off. My Daughter just moved out of home paying for everything herself with a part time Ikea job (she is still at school). She can afford a much nicer place (60m2) that when my generation moved out (which was nicer than when my parents moved out). Everything is cheaper in proportion to income by large margins. She laments she doesn't have much money and is poor because she can't afford a iPhone, laptop and 3 day concert tickets right *now*. Its going to take her a year or so to buy those "essential" items. Even appliances are much cheaper than ever before, a combination grill microwave is going for 50EU right now. Its just much cheaper in every respect. Hell my daughter is already planing two 2 week holidays in Croatia and France. Yea, really poor on a *part time job*. And yes, she pays for everything, i have not given her a penny.
Even for my wife and I, we spend less of our total income on rent/mortgage payments that my parents (less than half). Food is also really cheap in comparison, even with one income we can eat out many times a week. In short we have much more disposable income than 30-40 years ago.
Just look at commonly advertised products. Its no longer ovens or microwaves. Its luxury items that use disposable income, like smart phones and the like. Travel is so much cheaper these days that we don't really have the term "jet setter" anymore and just about everyone can afford tickets for international holidays more than once a lifetime. In the 60s and 70s you were lucky if you could afford it once in a lifetime! Now the current generation talks about OE (Overseas Experience) whcih is a fancy way of saying "bum around in another country".
Thing about the good ol' days is they weren't. You are not poor because you only have one car and a house/apartment with one toilet or can only afford a international holiday once every 2 years.
You entire product line will be on TPB even with DRM. It does not work!
You know what else is not safe. Gasoline in a atmosphere containing oxygen.
Honestly you would never get people to switch to gasoline today because of "safety concerns".
and how big are your routing tables?
My router that my ISP sent me 4 years ago, is dual stack and it is enabled by default. My ISP does not support IPv6 however. But in my experience most hardware does have dual stack support.
Not correct. Protons and anti protons are not fundamental particles, but are made up of quarks. 2/3 of the energy is thus released as charged Pions moving at close to the speed of light. They would dump most of their energy into the surrounding matter before decaying. The other 1/3 of the energy will go into gammas (from a 0 pion decay intermediary) which does interact with the surrounding matter, but over longer ranges.
Long story short. You get something very similar to a normal nuke, without the neutrons and fallout.
Look up antimatter catalyzed micro fusion. In other words, Yes.
Grow up. Both the troll and those who *feed* them are the biggest problem.
Why use the term "warmist"?
Why use the term deniers?
I like astrobiology, I may even end up working on something in the field. However, i would still mod you insightful if i had the mod points.
Sample size of zero indeed. Well one could say it is one. However in statistics this is still the same thing thereabouts.
The GM crops were made *sterile* to address the fears of the anti GM crowd that they would cross with non GM crops and contaminate the whole world!
If you had ever done any farming, you would know that you almost never ever keep "seed" from last years crop, you buy it cus it is so bloody cheap compared to everything else.
Nuclear fusion is getting closer. However it is tied up in the ITER boondoggle. Where most of the boondoggle has to do with politics rather than physics or engineering.
There are real physical limitations however. Even with perfect engines. Since lift is a reaction force we can calculate some BOTE figures. A lifting disk area of about 1m2 needs a downdraft velocity of 31 m/s for 1000N of thrust assuming a air density of 1kg/m3. That is 113km/h blast. The power required is 15.8kW (21hp) assuming a perfect engine to air coupling. This seems pretty reasonable. A pair of ducted fans need a diameter of about 80cm for a total disk area of 1 meter. Perhaps they can get a bit smaller!
Only thing is you have one problem. The "massively higher ISP" for jet engines (a stupid metric for a air breather) is because it collect's the Oxygen as it goes along with a bunch of Nitrogen. When you are traveling fast this cost a lot of energy or drag. This is the breakthrough they are hoping to get, but it would be a very big breakthrough, one that many aerospace engineers believe is fundamentally impossible. Also you have the other problem the the thrust to weight ratio of jet engines is awful compared to a rocket, about 10 vers 100. This eats your 30% before even starting. Finally there is costs, jet engines cost way more per kg (SSME not withstanding...). So its cheaper just to make a bigger tank (cheap), use more fuel+oxidizer(really cheap) and stick with rockets.
Despite everything, rockets are a real good match for the 9km/s deltaV needed for LEO. Planes don't look like trains, why do we insist that rockets should look like planes? They really do solve completely different problems.
Well i have had zero problems, and my window user friends didn't notice any missing features. In fact they were kinda surprised by how easily I added the web cam. Plug in out of the box, click on skypes setup thingy, web cam working. Several of my friends had to use the cams drivers to get it too work under windows.
YMMV but overall lately(5+years) I have been getting very very good mileage on my Linux installs.
Also as noted above. The input is not coherent, so even with a mixer you still would not get a beat frequency.
I think you still don't quite get coherent in this context. For a femtosecond they may be 180 out of phase, then the next femtosecond its 129 deg since another photon with different phase is now also getting absorbed. Hence you just don't get a beat frequency. Each photon has a different and independent phase.
http://www.dilbert.com/2011-03-29/
Yea, and then the news story posted to /. will be "Teacher takes cell phone off students" and about 90% of the /. comments will be outrage at the students rights getting violated.
Yea, who cares about rights and other unimportant things. Just let em do whatever they want. What could possibly go wrong.
depends on the source of hydrogen. In NZ natural gas (CNG) is pretty common for cars. However they are big heavy high pressure tanks that only give you about 300km range. Better than electric of course.
The also do have a relativity correction build in. Something of the order of micro seconds per week IIRC.