at 400 C, radiant energy starts doing a fair amount of the heat transfer. At 800 C, radiation overwhelms convection.
800 degrees C??? That's 1470 degrees F! Who has an oven that goes that high? That will turn just about anything into charcoal in under a minute.
Even 400 C-- 750 degrees F-- is quite a bit hotter than most ovens.
Agreed, I worded it badly. How about: ''How long had the last energy saving bulb that you replaced been working ?''
About six days, since you ask. Is that useful information?
But it is not intended to be a scientific survey.
Well, as the disclaimer says, Slashdot surveys aren't.
Following on from the current poll: How long did your last energy saving bulb last ? 0-1 months; 2-4; 5-8; 9-14; 15-23; 2 years; 2-3 years; 4+ years
If "last" means "most recently purchased", how do you answer for a bulb purchased two years ago that's still working? Or, for that matter, a bulb purchased last month?
My answer to this question is rather variable-- I've been changing out pretty much all of my bulbs for LED lamps. And I don't necessarily buy the cheapest ones. However, as it turns out, the ones I bought most recently were a couple of candelabra LED bulbs for the front entry chandelier, and they were pretty cheap. I was, however, also looking at LED strips to replace 4-foot fluorescent tubes-- if that had been my purchase, it would definitely have hit the "over twenty dollar" mark. (EarthLED has these. Some of these require rewiring to remove the ballast, although the Philips ones apparently are drop-in replacements)
I replaced the kitchen lights with LEDs. About $22 a pop. These are the larger lights, not the incandescent sized bulbs.
Excellent application for LEDs-- omni bulbs are far less efficient in that application than LED spots. (Any place where the required light is not omnidirectional is a good application for LEDs.)
...over many decades. Cars are driven on billions of trips-- trillions of miles-- per year. Really, truly, there are differences of many orders of magnitude here.
There aren't thousands of rocket launches.
It's not, and it also annoys me when people say that.
No single hurricane, heat wave, tornado, flood, wildfires due to drought, storm surge, hot summer, rainy winter is due to global warming, just as no single cold snap, hurricane free season, unseasonably cool spring, early winter storm is evidence that global warming isn't real.
Those are all weather. Climate is long term.
Trivially, no single car trip has an effect on global carbon dioxide. It's a collective effect. Being a collective effect does not make it nonexistent, but it does make it a problem hard to solve, since the problem is distributed.
So, here's an interesting question-- and I'm not being sarcastic here, I'm being real. Given that no one car trip has an effect on global carbon dioxide, but a hundred billion car trips do have an effect, what would be an appropriate approach to addressing this impact?
Wait, doesn't your rebuttal show that the earth's temperature will not spiral out of control leading to the death and destruction predicted?
I don't recall ever making such a prediction.
To be honest you make great points for the view that we are really in a geologic cold period and global warming is just returning us to average temperatures for geologic time frames.
Yep, that's pretty much correct. The Earth is, on the average, quite a bit cooler than it has been in the geological past. It does not always have ice caps.
It happens that this is the climate that we humans are used to, and we've rather built our habitats and our agriculture around. But, on a geological scale, a few degrees of warming, and melting the polar ice caps. is no big deal. It's not the end of the world.
--unfortunately, when we return the planet to the climate conditions of the Jurassic, we probably don't get the dinosaurs back. But then, if biological research keeps on track, we'll just make new ones.
Are you seriously arguing that if a criminal is caught on a surveillance camera, that must mean that they weren't doing anything wrong?
If he wasn't doing anything wrong, he could have done the download from his desk, not sneaking into a different institution on the other side of the city.
What about the amount of pollutants released with the launch of this satellite? Solid rockets and hydrazine aren't exactly environmentally friendly when you burn a million pounds in 12 minutes. The production of H2 and LOX is pretty dirty also, even if the final product is water.
OK, what about it?
I have a challenge for you. Using google, or your other favorite index-search tool, find out how much carbon dioxide is released by a single Delta-II launch. Then, look up how much carbon dioxide is put into the atmosphere per year by fossil fuel burning. Compare these two numbers. Do they differ by orders of magnitude? How many orders of magnitude?
Based on your findings, do you think that a rocket launch has a significant impact on global carbon dioxide levels? Do you think it has a measureable impact?
I assume you are aware that the current 380ppm CO2 in the Earth's atmosphere is pretty much an all-time geological low?
It's lower than in much of the Earth's history, but no, not anywhere near an all-time low. The all-time low is about half the current value... which, as it turns out, also was a much colder time in Earth's history.
Earth's CO2 levels over the past 600 million years or so have averaged about 1,500ppm, with peaks up to perhaps 7,000+ ppm:
And temperatures were much hotter, too. For most of Earth's history, the planet does not have ice caps.
There has historically been much more CO2 in our atmosphere than exists today. For example, during the Jurassic Period (200 mya), average CO2 concentrations were about 1800 ppm or about 4.7 times higher than today.
And temperatures were about 3 degrees C above what they are today.
The highest concentrations of CO2 during all of the Paleozoic Era occurred during the Cambrian Period, nearly 7000 ppm -- about 18 times higher than today.
And temperatures were 7 degrees C above current temperatures.
Carbon dioxide, on the average, was higher during the Ordovician, and average temperature during Ordovician period was 2C above modern levels (with sea levels 180 m higher). There was indeed a brief ice age-- about half a million years-- during the Ordovician. (for reference, the Ordovician lasted about 45 million years) But, guess what? That ice age corresponded to a low level of carbon dioxide. http://www.newscientist.com/ar...
Every single one of the examples you cite supports the basic observation that increased carbon dioxide correlates with increased temperature.
Yes, correlation is not causation. Nevertheless, you certainly can't point to this as evidence that carbon dioxide isn't related to global temperature
This was the coldest winter this country has ever seen. Fact.
Not a fact.
The winter of 2013 - 2014 was one of the ten coldest winters in history in the Midwest U.S.
It was the warmest winter on record in California, and set records for high temperatures in Alaska.
Overall, it was the 34th coolest winter in the contiguous U.S. since records began in 1895. The contiguous United States comprises 1.5% of the surface area of the Earth. One season, in 1.5% of the Earth's surface: this is weather, not climate
http://www.wunderground.com/bl...
http://www.weather.com/news/wi...
For the record, that video shows him walking casually into the room, not "sneaking" into it. You might see something nefarious going on, but I don't.
I suggest that you e-mail the 784,000 web pages that say Aaron Swartz snuck into the closet, and inform them they're using the English language wrong:
https://www.google.com/search?...
"sneaking" indicates that he made deliberate attempts not to be caught doing the action. It does not imply that he wore a trenchcoat and a stocking cap.
He could have downloaded the data from his own desk in his own office. Instead he went to the library and entered a wiring closet that was clearly not supposed to be open to the public.
If you were going to download a lot of data, would you choose a node with many hops to the server or just a few? I would pick the one closest to the server.
Nice rationalization, but his first few attempts at scraping the database was by downloading via the MIT wifi network, so it's clear that speed of access wasn't his main objective here. It was only after he was repeatedly blocked from doing that by wireless access (being blocked should have been a clue to him) that he snuck into the closet.
OOoooh. Did he sneak in on his belly like a cobra or on tippy-toes like the spy-vs-spy cartoon? Seems like that would just draw undo attention. Or maybe he just walked in, and you are making shit up.
Uh, since you don't seem to know anything about the case, why are you commenting?
Here are the first couple of links from a google search
The Washington Post: Jan 12, 2013 - "When MIT cut off access to its wireless network, Swartz snuck into an MIT network closet and plugged his laptop directly into the campus
What Aaron Swartz did at MIT - Daily Kos
Jan 13, 2013 - Between November and December 2010, Aaron Swartz accessed this room
Why We Should Remember Aaron Swartz - Businessweek Jan 13, 2013 - "It also has people like Aaron Swartz, whose work makes empires
Swartz Caught in a Closet (Update) | Simple Justice Jul 20, 2011 - "Aaron Swartz, a 24-year-old programmer and online political activist, has
And the video is online: https://www.google.com/search?...
THEGODDESSOFTHENETHASTWISTINGFINGERSANDHERVOICEISLIKEAJAVELININTHENIGHTDUDE
