First Snow

First Snow this season, looking at Ross and West River Streets in Wilkes-Barre.

A Year's Worth of Trash - In A Week.

Someone left this beauty for Wilkes-Barre Public Works to pick up. I used to think it was a lot when neighbors would have like three cans and two bags. This one tops all of them.

30 pound limit? How about 30 bag limit!

It's not even college students. If that were the case, it would be nothing but beer and beer paraphernalia. This even tops off the house that had six recycling cans filled over the top with Lionshead bottles.

At least they didn't illegally dump it all into the dumpsters at my apartment complex. Having lived next to the dumpsters last year, I witnessed that on many occasions.

Induction Heating

Induction heating is a method of electrical heating in which an alternating current passing through an inductor (the "work coil" ) sets up an electromagnetic field. A conductive object to be heated is placed inside of the inductor and the field sets up eddy currents in the object which circulate against the object's resistance, generating heat. Because of the many windings of the work coil compared with the single "winding" that is the object, the eddy currents are huge. And it is current - not voltage - that is responsible for heat production. Voltage serves only to push the current through the resistance, and since the object is usually a very good conductor, very little voltage is needed.

The inductor itself produces little heat - the heat is produced directly inside of the target object, which makes it faster and more energy efficient than other forms of electrical heating. I wanted to see if I could reproduce induction heating.

With limited resources available, I made a coil from some 24 AWG wire that I had from the Circuits Lab, and I made this coil to have an inductance (L) of about 0.25 millihenries, which corresponds to an 8 ohm impedance at 5000 Hz, 8 ohms being the output impedance of the amplifier I used as the power supply.

impedance = 2 * pi * 5000 * L

Inductance heating requires an AC current with a high frequency - 5000 Hz or higher. I used the signal generator software SigJenny to crank out a 5000 Hz sine wave signal, which fed into one channel of my 20 x 20 watt RMS TDA-2005 based audio amplifier. The output of this channel was connected to the work coil, and after inserting a bent-out steel paper clip into the coil, the amplification was turned on and the output cranked up. Superfluous buzzing and whining came from the other speaker (which was connected to the amplifier but no input signal was going in). I am sure that this noise came from inductive/capacitive coupling inside the amplifier circuit and the buzzing and chirping is coming from the computer. Within 10 seconds the "hot metal" odor appeared and bluing of the steel made it obvious that the induction heating had worked. I probably could have heated it red-hot but the 24 gauge wire wasn't taking it too well and I didn't want to mess up the amplifier.

I think that my coil inductance was inaccurate and the impedance was much lower than 8 ohms, due to the massive amount of heat coming from the vents on the amplifier. Since the right amplifier was not operating, the entire power supply was available to drive the left amplifier and the work coil. Thank goodness for the massive copper heat sinks that I put on the TDA-2005 chips!

Practical applications of induction heating are used in induction cooktops, where the eddy currents are induced in steel cookware causing it to heat directly. Induction heating is also used in foundries to melt metals. No impurities from fuel combustion enter the metal, and the magnetic fields can be used to stir the molten material, which is useful when alloys are being mixed.

Top Headlines in the U.S.

Here is a glimpse of the Breaking News brought-to-you by America's Broadcasting Corporation:

No wonder we can't fix our energy, environment, health care, education, transportation, and all of that other stuff. That's all secondary to Nicole Richie on drugs!

Campers from Hell

We went camping this past week, and a group of 5 guys, all probably about 18-19 years old, were in the site adjacent to ours. Below I have recalled just a few of the absolutely moronic things that they did.

• They attemted to dispose of their trash by fire, and once they realized that it would just sit and smolder and stink up the campground they opened up bottles of Aquafina and put the fire out with them.
• Their trash fire consisted of some cardboard, plastics, and about 15 Red Bull cans.
• They did not bother to clean out the fire ring before they left. This is probably because that is what they think a fire ring is supposed to look like - full of cans and charred trash.
• They ran the engine in their Chevy Suburban in order to listen to the radio in their campsite. Nothin' like a 350 horsepower V-8 powering a radio!
• They started up their car when they decided to go somewhere. It sat and idled for about an hour as all of them got dressed, gabbed on their cell phones, and dottled around. Gas Prices apparently are not high enough to keep people from being stupid. That Suburban probably gets about 10 miles per gallon while it is driving, but idling - that's ZERO MILES PER GALLON!
• They left their bread, Bisquick, and all of their other food sitting out when they would leave the campsite. The birds got into it and it ended up all over the place.
• Their trash was blowing through the entire campground.
• In order to light their charcoal fires, they stood over the grill and continuously sprayed lighter fluid into the burning grill, creating 2-meter high flames and an obnoxious odor.
• They blasted country music in which the themes of all of the songs was smoking and drinking. If that is the type of music they like, that is fine, but I know for sure that there were people in that campground who would not appreciate it.
• Every ten minutes at least one of them was getting into the Suburban and driving somewhere, then coming back ten minutes later. The interesting thing was that it took at least 3 minutes to get onto the main highway from the campground.
• They made good friends with the guy in the next site, who had an interesting habit of washing his hands with the graywater from the holding tanks on his camper.