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For longest life you should aim for a junction temperature of 60°C or less. How hot the heat sink should be to maintain that depends upon which LEDs you use, and what current you run them at. For example, the XM LED has a junction-to-case thermal resistance of 2°C/W. If you run them at 2...

What I might do in that case is mount the LED on a piece of aluminium plate, mount the aluminium plate flush with the ceiling, and then paint it to match. The paint probably wouldn't act as much of an insulator. The problem would be getting paint to stick well to the aluminium. Another...

You could run wiring to 120VAC code and just use it for low voltage by connecting to a transformer or power supply. Romex will work just fine for that actually. Not hard at all. I have a driver that can do it with about 8 parts ( and a few more if you want a dimming control ). Actually, what...

Cree will be releasing the XM LED this fall. Assuming that it's priced similar to their other emitters, it should drastically reduce the number of emitters ( and cost ) needed for a given output. Driven at 2 amps, about a dozen of these could light an average-sized room well. It also bears...

Interesting. The way I think SSD is eventually heading is towards dedicated M/B slots similar to RAM. In fact, I mentioned as much on storagereview.com years ago ( too lazy to look for the post ). This development seems to support that. And I'm having trouble even wrapping my head around 600...

Well, you're probably right that she was too young to do this, although I'm honestly of two minds here. On the one hand, yes, parents should protect their children against adult things which they are incapable of dealing with. On the other hand, children must be allowed to make mistakes, and...

Here's how I look at it. There is a very small subset of the population willing and able to engage in the sort of things which like this which might require an extensive rescue effort. In the grand scheme of things, on a per person basis, sending needed help isn't bankrupting anyone. Besides...

If I were in the same situation as Merc was, it would have taken all my self-control to not to use that kid for a little bonus lesson. "Hey class, we're going to have an impromptu physics demonstration on the concepts of acceleration and momentum. First we accelerate Mr. Wiseguy up to a good...

The bottom line in the USA is no insurance, no medical care. Those who are poor are covered by Medicaid, those who are old are covered by Medicare. Some are covered through their jobs. The rest buy insurance on their own if they can ( last I heard that cost anywhere from $800 to $2000 per...

How long you can sustain a given g-force depends upon orientation. You can sustain 14g for a while with full immersion. The chart plots g-force versus g minutes. It looks like it's possible to accelerate at 14 g while immersed just long enough to reach orbital velocity ( 17,500 mph ). That...

We need oil for now BUT the part which annoys me is our needs may have been WAY less had we started systematically getting off the stuff after the first oil crisis in the 1970s. Cars got more efficient for a while which was good. And GM made an attempt at an electric car in the early 1990s (...

I agree. The more I read about this the madder I get. Sadly, in the end BP will likely end up paying for a fraction of the damage they caused, the area around the Gulf of Mexico will be messed up for generations, and then we'll all wait until the next screw-up occurs. Only next time it might...

No, like I said, absolutely no money to travel. Going into Manhattan is about all I can manage as far as trips these days. Also, no time for it. I'm not one for flying ( uncomfortable, risky, basically a totally uncivilized way of traveling ), so a trip to the Far East would mean three days...

Yep. That would be what BP calls a "junk shot". :mrgrn:

Nope, never been there at all. I just don't have the money or desire to travel. What you say is certainly true, but I have heard of company heads and politicians offing themselves in the past. Those times are probably mostly past though. Nowadays from what I've read Japan is getting to be...

I'm anti anything which isn't sustainable for the long haul. The very idea that everyone, including the lower income brackets, should own a home is what created both the real estate bubble ( and the subsequent crash ) and a lot of exurban sprawl. If enough people living in suburbs are willing...

In theory you may be right except for the fact this doesn't work in practice due to the strange way many suburbs are zoned. You'll have a residential area, and the nearest commercial area might be 3 miles away, despite the fact that there is nothing but empty land in between the residential and...

It's not only acceptable, but often expected, for a public official who massively screws up to take his/her life for the sake of honor. If BP, for example, were a Japanese company the President would probably have killed himself already. As much as I hate to say it, this concept has a certain...

No, we'll probably need sustained prices over $5 a gallon for that to happen. Also, I should point out the problem isn't one of gas prices, it's one of infrastructure. Much of the infrastructure supporting suburbia was built a few decades ago, at much less in real dollars than it would cost to...

Well, I'm actually seeing something like that. You'll have many ( most ? ) people either in cities or relatively dense suburbs, with those in other areas needing to be pretty much self-sufficient as far as providing their own power, growing their own food, etc. Either way is actually...

It's actually worse than that And more to the point Note the date on the first article-well before any of this happened, and IMO the last half of the article is way too optimistic. The mortgage crisis simply accelerated an underlying trend. The exurbs are dying, while cities are mostly...

This is what happens when you treat people like worker ants: “Foxconn’s production line system is designed so well that no worker will rest even one second during work; they make sure you’re always busy for every second,” says Li Qiang, executive director of the China Labor Watch, a New...

I'm curious as to why monitors haven't increased pixel count so that they display at 300 dpi or better. We're still stuck at ~100 dpi when today's PCs can easily handle displays with much higher resolution. The goal should be to have the pixel size roughly equal to the eye's resolution at the...

Interesting. This explains why I've spent more hours than I care to think helping improve MS Train Simulator, and then basically gave away whatever I learned. Same thing for a bunch of others involved. None of us cared about money. In fact, there really wasn't money involved because nobody...

The reason Americans typically have large refrigerators has to do with yet another inefficiency-sprawled out living. Many people shop for groceries at big box stores perhaps once or twice a month. As a result, they need the space to store a large amount of perishables. Back in the days when...

Unless of course you get the replacement LED for free like I did. :mrgrn: I tested a bunch of LED bulbs for someone on CPF and got to keep them. Most weren't that great ( i.e. they used 5 mm indicator LEDs which are prone to fading ). A few are decent. The one I stuck in the fridge uses...

Probably closer to 3:1 for typical household refrigerators. Also, the room is a closed system, so the net amount of heat added is only whatever the compressor uses. For example, if a 100 watt compressor moves 300 watts of heat, yes, you will have 400 watts total coming out the back ( or...

Yes, probably Samsung and WD will release their own 3 TB drives in a relatively timely fashion after Seagate. What really excites me more than the increase in maximum capacity is the fact that this development should decrease prices of 1 to 2 TB drives. A 1.5 TB drive will now be two-platter...

Actually, I read an article about hard disk manufacturers seriously considering migrating to 4K sectors instead of 512. The reason was 4K is commonly the smallest unit used by various file systems. I don't know if Seagate plans to do this with the 3 TB drives or not but it would make sense...

I haven't giving up on exercise ( i.e. cycling in my case ), but I've found a combination of things keep me from doing as much as I'd like. For one, the weather doesn't always cooperate. Rain or snow forget it. Temps under about 30°F ( or much over about 80°F unless the humidity is low )...

http://www.candlepowerforums.com/vb/showpost.php?p=2439222&postcount=178 Much colder than your needs ( I've had it down to -58°F ), and much more expensive ( IIRC I spent over $1000, and about 3 years of my free time, trying different things ). Next time I have a big stretch of time free I may...

Speaking of high-speed trains and China ( udaman's post a few pages back ): China Offers To Build High-Speed Rail to California China Wants 380 km/hr Trains First off, given the cost overruns and delays typical of any infrastructure project done by American workers, I think California should...

I've consistently ate breakfast my entire life. It still didn't stop me from gaining about 35 pounds from my mid 20s up until now ( actually, my weight has been stable at 195-205 for at least the last decade ). I might be losing some lately between cutting out soda and getting on my bike at...

It sounds like your mortgage broker was dealing with him.

All I said was these programs don't spend a lot of money on overhead. Their insolvency is another issue entirely. At least what funds they do take in are mostly paid out in benefits. Social Security's overhead is only around 1%. Now remember that the recent health care bill will require...

They should have went with single payer to start with. If the government is going to force me to buy insurance one way or another ( and I'll agree that it has no business doing this ), then to me single payer makes a lot more sense. The other way I pay insurance company, insurance company...

Until we're able to commercially produce light-based CPUs ~3.5 to 4 GHz is about as fast as we're going to be able to go. There are inherent limits on clock speed due to things like trace capacitance/inductance. You really can't economically get around these limits. This is why we started...

There are organizations that already do this. They're called insurance companies. They're far worse than any government "death panel" would ever be. Not only do they often not cover things they claim they do as part of your policy, but they'll drop you altogether once you start costing them...

In the legislative chambers of course. Judging by some of the laws being passed, it looks like they're already smoking some strong stuff. :drinka:

I'll agree the latest push to take ALL salt out of restaurant is misguided. However, there's nothing good about smoking, transfats, or for that matter high-fructose corn syrup. I'm glad we've gotten rid of transfats. I hope we do the same with HFCS, and any other junk currently in food which...

Ouch! I feel a little better now. I spent ~$7000 on dental work from 1993-1995, didn't see a dentist again until last year, and then spent close to $4000. End result though is 29 teeth still remaining, 2 of the three pulled ones are wisdom teeth, the other is a second molar. 15 teeth ( all...

Possibly the first instance of Twitter actually being useful for something besides massaging people's egos: Back on Madison Avenue, Austin Horse quickly realized his bike was gone and immediately took out his cellphone and posted to Twitter (“STOLEN BIKE! My orange gangsta just got stolen 28th...

That makes three of us. All the eneloop AAs I bought cost me $2.50 or less per cell. That's cheap enough in my book. I wouldn't even want the Eneloop Lites unless they cost like a buck each.

That's another thing I neglected to mention. In general power plants will upgrade as time goes on in terms of both efficiency and emissions. ICE cars on the other hand generally get worse once they leave the factory. That goes double these days when many are struggling just to pay for fuel...

And foreclosing doesn't do you much good when the house is worth less than the mortgage on it.

I found a whole site dedicated to using GPUs for general purpose computing: http://gpgpu.org/ Unfortunately, it doesn't look like anyone has developed a driver of some sort which can reroute floating point operations from any application from the CPU to the GPU.

To save you a bit of time, here is a link about the power grid. About halfway down the page: Transmission and distribution losses in the USA were estimated at 7.2% in 1995. In general, losses are estimated from the discrepancy between energy produced (as reported by power plants) and energy...

I'm wondering about that myself. I though PATA was dead for all intents and purposes.

Not only that, but a CUDA supported GPU isn't even available for the AGP 4X/8X slot on my M/B. Looks like I'm out of luck then. :(

I'm using Circuitmaker 6.0 student version. It's not longer supported or updated by the original programmer, so no chance of the code being updated to take advantage of GPUs. Like I said first post, I'm more curious for academic reasons if I can get this and a few other computation intensive...