It seems that ignorant politicians are causing more damage that good with their "Eco-illogical" measures, like the banning of incandescent bulbs. Their favorite "luminous idea" is that CFL's are the panacea. They aren't. CFL's have many drawbacks, they contain sizable quantities of mercury. Should a CFL break and disperse the mercury inside a room, the decontamination would be very costly and difficult, unless you want people living in that bedroom to be exposed to mercury vapor! Have you seen any warning on the CFL's package, or instructions on how to properly dispose of a broken CFL? They also use many electronic parts that end up in the garbage, and some of them are not very environmental friendly at all. We all pay for their true price through subsides and government intervention.
Their power factor is a lousy 0.5 or so. They require to be used in applications that allow them to reach maximum brightness (not for stairs or closets where they will only be lighted for less than a couple of minutes). They are not easily dimmable and require well ventilated enclosures. They are a temporary (and incomplete) alternative to the incandescent bulbs until LED's are available at better prices and reliabilty. Amclaussen.
Same case as the stupid propaganda claiming that Aluminum wiring is better than copper! while aluminum wiring cost is lower, both conductivity and corrosion aspects point to copper being the best material by a long shot. But cheap is the word nowadays. Amclaussen.
YES!, patb2009, I TOTALLY AGREE! That's one of the MAIN reasons why Americans (the U.S., in particular) feed & support about ONE HALF the free world, and probably one quarter the "not-so-free" world, INCLUDING our avowed enemies!!!!!!!!
I said "Americans", because like it or not, Canadians & Mexicans ARE also "Americans", since we all reside in countries defined by the continent of North America!
Well, everyone is grumbling about the dissimilar metals issue of aluminum sockets with brass rivets.
Has no one realized that this results in an aluminum-to-aluminum contact between the socket shell and lamp? Changing to a brass socket shell would provide a very large area of dissimilar contact between the threaded aluminum socket and the threaded aluminum bulb base, likely resulting in seizure. It's dangerous to twist a bulb off its base and more dangerous to remove the base from the socket--ideally with safety goggles and power off using pliers or potato. But how many homeowners will do it with bare hands (lacerated fingertips) and no goggles?
On that basis the aluminum socket is safer than a brass one.
Jim, thanks for the current information, or at least fairly current. I knew that it all had to do with cost, nothing else drives choices of materials for a lot of stuff today. Probably if poor quality steelm were cheaper they would be made of that.
The very cheapest quality of aluminum for castings is unique in that it develops rust spots, since it includes ireon and steel fragments.
JIm, my guess is that in the line of really cheap alloys that the aluminum alloy used for light sockets is quite cheap, while the copper that draws nicely costs more. Possibly not much more, but perhaps a penny a pound more. Enough to cause quality to be sacrificed for price.
Meanwhile on the other topic of 'Draw-capable" alloys, you suggested that Aluminum is easier to deep-draw. In my experience working with draw dies, two alloys called NickelSilver CDA770 and CDA735 were most often chosen because of their superior malleable stretch during the draw. (These materials are primarily Cu base, so the name NiAg is misleading).
I remember once trying an aluminum sheet in an existing die designed for CDA770 (as a cost-saving idea) and the Aluminum test part split open. Point being, I concluded copper was a better draw stock than aluminum. Maybe the rolled threads for the light socket base helped provide better 'draw' integrity, in these aluminum sockets.
Of course, you are right –I suffered a lapse there, thinking for a moment that brass was a natural element. In my mind, I had set Bronze aside as an Alloy, and that (incorrect thought) left Brass remaining as an element. Had to go back and look at the Periodic Table and a Bronze/Brass Alloy sheet I have. Thanks for the correction.
A slew of announcements about new materials and design concepts for transportation have come out of several trade shows focusing on plastics, aircraft interiors, heavy trucks, and automotive engineering. A few more announcements have come independent of any trade shows, maybe just because it's spring.
Samsung's Galaxy line of smartphones used to fare quite well in the repairability department, but last year's flagship S5 model took a tumble, scoring a meh-inducing 5/10. Will the newly redesigned S6 lead us back into star-studded territory, or will we sink further into the depths of a repairability black hole?
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.