If people actually start taking this nonsense seriously, it might be that we get some serious drop in beachfront property prices. Great to live within walking distance of the sea.
Our scientific equipment "Declic" was sent to the ISS last august. It runs Linux and uC-OS II on a whole pile of microprocessors. The Linux of the part of the system that we built was completely custom built based on "linux from scratch". For an interesting read: Linux Journal
The 2.6 kernel was state of the art when we built it, but we needed its lower latency features.
Incorrect. They've actually helped out quite a few OSS projects including samba, ODF, FireFox, Apache to name but a few. 10 years ago I would have agreed with you, but Microsoft are much more open to interoperbility now than ever before.
What a load of baloney:
MS grudgingly gave the Samba people a pile of incomplete documentation, after it was forced to do so by the EU
MS desperately attacked ODF, came up with its pile of crap MS-OOXML, which it specifically named such that it was easily confused with ODF, and then when they managed to force it through the ISO organization, in the process pretty much destroying that organization, they abandoned the standard because even their own Office program didn't implement it.
Firefox? You're full of it.
Apache, they gave money to the Apache foundation. We don't know why yet, maybe to make apache run better on Windows.
I've used Macs for 20 years, and Linux boxes for 8 years, and i've never done a clean install just because my system was no longer responsive. I've upgraded Kubuntu since 8.0 to the current 9.4 without any trouble.
Just so you know that there's some price to pay for using Windows.
For me 5 weeks (or more) of paid vacation per year is better than 2. Or having more than 2 weeks warning before you are fired also counts as something. Or having a minimum wage that you can actually live on, or not having gun-ridden ghettos in every large city.
I like the quality of life in the Netherlands way better than that in the US, and I've spent about a year of my life in the US.
Solanki '04 disagrees with you
on
Sunspots Return
·
· Score: 1
Looking at Solanki 2004 you will see clearly that even scientists that believe in AGW show conclusively that the sun was unusually active in the later half of the last century:
According to our reconstruction, the level of solar
activity during the past 70 years is exceptional, and the previous
period of equally high activity occurred more than 8,000 years
ago.We find that during the past 11,400 years the Sun spent only
of the order of 10% of the time at a similarly high level of magnetic activity and almost all of the earlier high-activity
periods were shorter than the present episode. Although the
rarity of the current episode of high average sunspot numbers
may indicate that the Sun has contributed to the unusual climate
change during the twentieth century, we point out that solar
variability is unlikely to have been the dominant cause of the
strong warming during the past three decades.
As a European with a taste for good cheese, from Dutch Goudse or Leidse kaas, or pitjeskaas to French blue cheese or brie or goats cheese, I've always been confused with American Cheese:
First: it's not called cheese: its' called American Process Cheese Food (look on the Kraft bricks)
Second: which part are you supposed to eat? The thin crunchy transparent stuff that is around the square yellow substance, or the yellow plastic substance with no flavor or texture?
drag scales quadratically with speed, yeah so what. I dropped the speed by 10%, so the drag dropped by 19%. Integrating this over the whole 100kph to 90kph has a few % error, nothing to invalidate this back of an envelope experiment.
Also a Renault 5 is not a 'normal sedan'. It is quite a small hatchback from the 1980ies.
I did not analyze road surface and air resistance, I measured both of them combined, by measuring the deceleration of 0.1m/s^2 with no engine driving the car, and the gearbox disconnected.
Using these values, and the cars specified 90kph fuel consumption, I calculated efficiency to be about 5% for this car at 90kph/flat level road.
Your 20% value is a value derived from authority. I specifically posted this whole thing to get other people involved in doing the actual experiment, which is about as easy as it gets.
How about the force calculation; the 90N of force that is slowing down the car at 0.1m/s^2. Canceling this drag force with 90N of propulsive force gets you the same power: 90N * 27m/s = 2.5kW.
You're talking about alternator and such. Those are losses; they don't make my box go forward on the road.
I did not measure the fuel consumption; I just used the manufacturer spec that said that it takes so much fuel to go a steady 90kph. I just used a simple trick to determine the actual drag at appx. 95kph (90N).
So to reiterate. I takes 2.4 kW to move that car with its wheels, body, axles and such at 100kph on a flat and level road. The amount of primary energy consumption is 44kW. 95% of that 44kW gets wasted as heat in the exhaust, heat in the radiator, heat in the gearbox, heat in the diff, heat in your electric system,...
My 0.1 m/s^2 deceleration for a 900kg car shows a drag force (wheels + air + differential + bearings + exit shaft of gearbox) on the car of 90N. I don't need to know where that 90N is coming from.
So I don't see why I can't do what I did. I think it's completely valid.
You're probably correct, but I have no other data. I presumed that the manufacturer spec: 1 l/18km at 90kph meant flat road and such.
That's the only problem data that I can see in my little experiment.
No, I did not say engine efficiency, I said system efficiency. My box on wheels generates 90N of drag from the air and the road, and takes 2.4 kW to keep at 100kph. This indicates that if I had hooked up efficient electric motors to the wheels it would take me say 2.7 kW to keep my car running at 100kph.
The fuel that my engine uses at 100 kph is specified at 1l/18km, so that's what I've calculated; this is the fuel usage that would normally be used to provide the 90N of forward force to keep the car at this speed.
I'm quite well aware that IC engines can be somewhat more efficient than 5%, but at almost idling loads (100kph on a flat and level freeway), they are probably not too good.
But please keep thinking about this, I don't see any problems with my reasoning, but that doesn't mean I'm right.
Another way to calculate this:
I lost 3 m/s in 30 seconds, so my deceleration is 0.1m/s^2. The car weighs 900kg, so F= 90N. If I had applied 90N, the car would have stayed at speed.
90N * 28m/s = 2.5kW. Same figure.
The funny thing is that this calculation shows that engine friction and the primary conversion efficiency of the thermal energy to mechanical energy conversion are far more important than air drag and wheel resistance at freeway speeds.
My text says 717kJ delta, but that is 71.7 kJ. I used the correct number to reach 2.4kW.
I stand by my conclusion that if we could apply 2.4kW with 100% efficiency to the wheels, we could keep this car going steady at 100kph on a flat road with no wind.
Major losses are: 1) the engine itself, at best some 25%, when running at optimal load, 2) the gearbox and stuff, 3) auxiliary loads (alternator, airco).
You can see from this whole calculation that air drag and such are hardly important.
I stand by the result of my measurements and calculations. I agree that it takes more power to accelerate the car to 100kph, but the 2.4 kW to keep it at that speed stand. Also I don't think I'm wildly wrong with the gasoline energy content.
Show me were I made a mistake...
I once measured my cars efficiency (an old Renault 5).
I drove 100 kph (28m/s) on a flat freeway, with no wind, and set the gears in neutral. It took the car about 30 seconds to slow down to 90kph (25m/s). The car weighs about 900kg.
So we have E0=0.5*m*v*v = 353kJ and E1=281kJ. The car lost 717kJ in 30 seconds or 2.4kW
So it takes just 2.4kW to keep a small car cruising at 100kph on a freeway. The stated gas consumption of that car is about 1 liter/18 km at 90 kph so 1.3 ml/second of gasoline. Gasoline has ca 32MJ/l energy content, so 1.3ml/s is equivalent to 44kW. The system efficiency of a car cruising on a flat freeway is about 5%!
Do the experiment yourself and see what numbers you come up with. It's also a really good highschool experiment.
In France you can get 3.6MB/s satellite internet for 40 euro per month. So why would you pull cables? Only hardcore gamers will be in trouble, ping times of 600 ms are typical. But then, keep the gamers in the city please:-)
"Bad road surface ahead" in the Netherlands is indeed a joke. I've travelled all over the world, and a 2 cm deep hole in a Dutch road is considered a major traffic hazard, requiring extensive warning signs.
There's another one that is a sign a Belgium: "Traffic jam possible". In Belgium this might mean that you occasionally have 10 or 20' delay. My suggestion is that we put those signs at every border crossing into the Netherlands to warn foreigners of the fact that there will always be traffic jams at any time of day or night.
I travel a lot in France on holidays (I'm an avid rockclimber) to all corners of the country, generally in the most rural and steep places. I don't think there is even one unpaved road in France, they're all good quality, from the excellent toll roads down to the smallest departmental or county road.
Large parts of France are thinly populated: less then 50 person/km2, but the roads are always good.
I guess it all has to do with what people find important, and the French do like speeding:-)
Slashdot Mirror
If people actually start taking this nonsense seriously, it might be that we get some serious drop in beachfront property prices. Great to live within walking distance of the sea.
Our scientific equipment "Declic" was sent to the ISS last august. It runs Linux and uC-OS II on a whole pile of microprocessors. The Linux of the part of the system that we built was completely custom built based on "linux from scratch". For an interesting read: Linux Journal
The 2.6 kernel was state of the art when we built it, but we needed its lower latency features.
What a load of baloney:
MS grudgingly gave the Samba people a pile of incomplete documentation, after it was forced to do so by the EU
MS desperately attacked ODF, came up with its pile of crap MS-OOXML, which it specifically named such that it was easily confused with ODF, and then when they managed to force it through the ISO organization, in the process pretty much destroying that organization, they abandoned the standard because even their own Office program didn't implement it.
Firefox? You're full of it.
Apache, they gave money to the Apache foundation. We don't know why yet, maybe to make apache run better on Windows.
System 7 was ok. I never reinstalled it for any reason, and I've always just upgraded my Macs (some 7 or 8 over the years).
Just so you know that there's some price to pay for using Windows.
xlsy?
For me 5 weeks (or more) of paid vacation per year is better than 2. Or having more than 2 weeks warning before you are fired also counts as something. Or having a minimum wage that you can actually live on, or not having gun-ridden ghettos in every large city.
I like the quality of life in the Netherlands way better than that in the US, and I've spent about a year of my life in the US.
Even the anti skeptics site skeptical science refers to him, so no Solanki is not a climate heretic.
US gallon or Imperial gallon?
As a European with a taste for good cheese, from Dutch Goudse or Leidse kaas, or pitjeskaas to French blue cheese or brie or goats cheese, I've always been confused with American Cheese:
First: it's not called cheese: its' called American Process Cheese Food (look on the Kraft bricks)
Second: which part are you supposed to eat? The thin crunchy transparent stuff that is around the square yellow substance, or the yellow plastic substance with no flavor or texture?
drag scales quadratically with speed, yeah so what. I dropped the speed by 10%, so the drag dropped by 19%. Integrating this over the whole 100kph to 90kph has a few % error, nothing to invalidate this back of an envelope experiment.
Also a Renault 5 is not a 'normal sedan'. It is quite a small hatchback from the 1980ies.
I did not analyze road surface and air resistance, I measured both of them combined, by measuring the deceleration of 0.1m/s^2 with no engine driving the car, and the gearbox disconnected.
Using these values, and the cars specified 90kph fuel consumption, I calculated efficiency to be about 5% for this car at 90kph/flat level road.
Your 20% value is a value derived from authority. I specifically posted this whole thing to get other people involved in doing the actual experiment, which is about as easy as it gets.
How about the force calculation; the 90N of force that is slowing down the car at 0.1m/s^2. Canceling this drag force with 90N of propulsive force gets you the same power: 90N * 27m/s = 2.5kW.
You're talking about alternator and such. Those are losses; they don't make my box go forward on the road.
I did not measure the fuel consumption; I just used the manufacturer spec that said that it takes so much fuel to go a steady 90kph. I just used a simple trick to determine the actual drag at appx. 95kph (90N).
So to reiterate. I takes 2.4 kW to move that car with its wheels, body, axles and such at 100kph on a flat and level road. The amount of primary energy consumption is 44kW. 95% of that 44kW gets wasted as heat in the exhaust, heat in the radiator, heat in the gearbox, heat in the diff, heat in your electric system,...
My 0.1 m/s^2 deceleration for a 900kg car shows a drag force (wheels + air + differential + bearings + exit shaft of gearbox) on the car of 90N. I don't need to know where that 90N is coming from.
So I don't see why I can't do what I did. I think it's completely valid.
You're probably correct, but I have no other data. I presumed that the manufacturer spec: 1 l/18km at 90kph meant flat road and such.
That's the only problem data that I can see in my little experiment.
No, I did not say engine efficiency, I said system efficiency. My box on wheels generates 90N of drag from the air and the road, and takes 2.4 kW to keep at 100kph. This indicates that if I had hooked up efficient electric motors to the wheels it would take me say 2.7 kW to keep my car running at 100kph.
The fuel that my engine uses at 100 kph is specified at 1l/18km, so that's what I've calculated; this is the fuel usage that would normally be used to provide the 90N of forward force to keep the car at this speed.
I'm quite well aware that IC engines can be somewhat more efficient than 5%, but at almost idling loads (100kph on a flat and level freeway), they are probably not too good.
But please keep thinking about this, I don't see any problems with my reasoning, but that doesn't mean I'm right.
Another way to calculate this:
I lost 3 m/s in 30 seconds, so my deceleration is 0.1m/s^2. The car weighs 900kg, so F= 90N. If I had applied 90N, the car would have stayed at speed. 90N * 28m/s = 2.5kW. Same figure.
The funny thing is that this calculation shows that engine friction and the primary conversion efficiency of the thermal energy to mechanical energy conversion are far more important than air drag and wheel resistance at freeway speeds.
My text says 717kJ delta, but that is 71.7 kJ. I used the correct number to reach 2.4kW.
I stand by my conclusion that if we could apply 2.4kW with 100% efficiency to the wheels, we could keep this car going steady at 100kph on a flat road with no wind.
Major losses are: 1) the engine itself, at best some 25%, when running at optimal load, 2) the gearbox and stuff, 3) auxiliary loads (alternator, airco).
You can see from this whole calculation that air drag and such are hardly important.
I stand by the result of my measurements and calculations. I agree that it takes more power to accelerate the car to 100kph, but the 2.4 kW to keep it at that speed stand. Also I don't think I'm wildly wrong with the gasoline energy content.
Show me were I made a mistake...
I once measured my cars efficiency (an old Renault 5).
I drove 100 kph (28m/s) on a flat freeway, with no wind, and set the gears in neutral. It took the car about 30 seconds to slow down to 90kph (25m/s). The car weighs about 900kg.
So we have E0=0.5*m*v*v = 353kJ and E1=281kJ. The car lost 717kJ in 30 seconds or 2.4kW
So it takes just 2.4kW to keep a small car cruising at 100kph on a freeway. The stated gas consumption of that car is about 1 liter/18 km at 90 kph so 1.3 ml/second of gasoline. Gasoline has ca 32MJ/l energy content, so 1.3ml/s is equivalent to 44kW.
The system efficiency of a car cruising on a flat freeway is about 5%!
Do the experiment yourself and see what numbers you come up with. It's also a really good highschool experiment.
In France you can get 3.6MB/s satellite internet for 40 euro per month. So why would you pull cables? Only hardcore gamers will be in trouble, ping times of 600 ms are typical. But then, keep the gamers in the city please :-)
I just got back from the Haute Queyras, and there I found one or two dirt roads, but it seems they were more for forestry than for general use.
"Bad road surface ahead" in the Netherlands is indeed a joke. I've travelled all over the world, and a 2 cm deep hole in a Dutch road is considered a major traffic hazard, requiring extensive warning signs.
There's another one that is a sign a Belgium: "Traffic jam possible". In Belgium this might mean that you occasionally have 10 or 20' delay. My suggestion is that we put those signs at every border crossing into the Netherlands to warn foreigners of the fact that there will always be traffic jams at any time of day or night.
Large parts of France are thinly populated: less then 50 person/km2, but the roads are always good.
I guess it all has to do with what people find important, and the French do like speeding :-)