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Showing posts from June, 2012

Oscilloscope Peak Via Slope

The first oscillating magnetic field superconductor levitation tests yesterday went great. With the Peavey power amplifier driving the electromagnet, the superconductor levitated at frequencies up to 164 Hz. An interesting measurement problem arose that required the use of a math trick to compensate for the limitations of the oscilloscope. Our oscilloscope has a maximum vertical range of 5 volts per division. There are 8 vertical divisions on the screen, so as long as the oscillating voltage from the amplifier is less than or equal to 40 volts peak to peak, we can read its peak value by counting divisions on the oscilloscope screen. To attain the necessary levitation force however, the oscillating voltage applied to the electromagnet had to be greater than 40 V peak. Instead of readable trace like the one shown above, the oscilliscope looked like:



There aren't enough divisions on the scope screen to read the voltage. This is where the math trick comes in. We know the fre…

History, Ham Radio, and Touch

My dad and both of my grandfathers are masons. Consequently, as a kid, I could always find a copy of Albert Pike's, "Morals and Dogma", or a lodge monitor, full of geometric diagrams, on the bookshelf. My dad and I would talk about geometry problems like Euclid's 47th problem, the Pythagorean Theorem. Dad told a story that Euclid had proposed this problem to his student Pythagoras by sketching it in the sand while walking along the beach. Then, by drawing out a right triangle and making squares of the sides, Dd would show that the squares in the Pythagorean formula had geometric as well as mathematical meaning. The areas of squares made from the short legs of the triangle will add up to the area of the square made from the long leg of the triangle. Geometry presented as a story instead of a dry rigorous science is what held my interest as a kid and is what has piqued my recent interest in the new series "Touch" and "Daybreak" with their re…

Radiating Superconductors, Arduinos, and Data Acquisition

While doing research for the NMSU Superconductor Gravity Experiment, I came across an article published by J.E. Hirsch of UCSD. He writes that his 'hole theory of superconductivity', (more on this in a later post), predicts that x-ray photons should be emitted by a superconductor similar in size to our sample when it changes from the superconducting to the non-superconducting state. The superconducting sample I'm using cycles between states each time a set of levitation force data is taken, so I decided to go ahead and try to detect the radiation predicted by Dr. Hirsch as a side project. A Geiger counter is being used as the radiation detector because it was readily available. Data acquisition with the Geiger detector turned out to be a little more work than I expected.

My first thought was that I could simply record the beeps coming from the Geiger counter and then use Audacity to analyze the resulting audio file. There were a few issues that cropped up with this …

Daybreak Chapter 4, Wardenclyffe and Real Physicists

Chapter 4 of Daybreak premiered yesterday! It was a little mushy and a little short for my taste, but it had another great physics quote delivered by Charles:
"oceanic overturn followed by a series of mega-tsunamis and hyper-hurricanes"
Oh the alliteration!

There were also some interesting references to Wardenclyffe, Tesla's last laboratory. Which brings up the question, do real physicists hang out around Wardenclyffe?




Although the transmitting tower was torn down and sold for scrap to pay Tesla's hotel bills, the laboratory building behind the tower is still there, and yes, yours truly got to hang out at Wardenclyffe for a day. A group on Long Islan, the Tesla Science Center, is working to restore Tesla's last lab into a working science museum and makers space. In support of the efforts to restore the lab, I worked with Jeff Murray, K1NSS, ham radio cartoonist extraordinaire, Diana Eng, Make magazine contributor, fashion designer, and NYC ham radio afi…

Update on the NMSU Superconductor Gravity Experiment

First, a recap:

In 1992 Eugene Podkletnov reported a possible gravitational field shielding from a rotating, levitated superconductor. NASA tried to duplicate his experiment but didn't complete it. We were able to borrow NASA'S equipment to attempt to replicate Podkletnov's experiment. After quite a bit of research it became clear that none of the replication attempts have succeeded in levitating the semiconductor, (via the Meissner effect and flux pinning), at the magnetic field frequencies specified by Podkletnov. At this point we backed up and decided to study the dependence of the levitation force with respect to frequency. All this is detailed more fully in the presentation below.


I've been working on a torsion balance to measure the levitation force. The balance isn't my design, I found it in the Review of Scientific Instruments.
From NMSUSCGE
The balance consists of a stretched steel wire with an attached boom that is free to rotate. When a steel w…

Daybreak, Tesla, the New Yorker and of course Physicists

I spent some time playing around with the Daybreak ARG, (alternate reality game), android app this morning. Prior to this morning I had no idea what an ARG was. Players solve puzzles within the app to receive new clues. In addition, players are encouraged to post JackBoxer, (the name of the Daybreak game), logos near their locations to receive additional messages via SMS from the game's coordinators. The mathematical puzzles in the app had me reviewing Fibonacci sequences and looking up Platonic Solids. AT&T and Daybreak's creative team have done a great job of assembling material that gets people enthused about math and science. Some of the game media even mentions quark and gluon jets ala the experiments going on at Brookhaven National Laboratory only a few miles from Tesla's Wardenclyffe laboratory. Some of the game's clues have players speculating about Feynman diagrams and string theory.

Several of the game's documents mention Tesla living in the…

Daybreak and Real Physicists

The new AT&T internet serial Daybreak is awesome! I watched the first three episodes last week after I heard about it from the Chief Engineer of the New Yorker Hotel. The story, so far about a race to find one of Nikola Tesla's lost inventions, portrays physicists in an exciting light if nothing else. But is it real? Here's a check of how the physicists in Daybreak compare to real life physicists. Since I'm not too bashful, I'll serve as the real life physicist, (well physics student).





Do Physicists Really Live in Trailer Parks?DaybreakReal Life
Of Course they do! Have you ever checked rental prices near Brookhaven National Laboratory? Ideally, your trailer should fit easily behind your car so you can move from laboratory to laboratory with ease.




Do Physicists Drive Motorcycles?
DaybreakReal Life
Yup! Although ours tend to be wired for data acquisition.



Do Physicists Have Access to Desert Hideouts Full of Barrels?DaybreakReal Life
They do! You have to have a…

Muon-Catalyzed Fusion

I came across muon catalyzed fusion this week. The basic gist of the idea is this: When you replace the electron on a hydrogen atom with a muon, the radius of the atom reduces by a factor of 200. This allows the atom to come much closer to the nuclei of other atoms where there is a finite chance that it will overcome the Gamow barrier penetrating into the other nuclei and achieving nuclear fusion.

The muon is a particle that is identical in every way to the electron except two. It is roughly 200 times more massive than the electron. The extra mass is why it's orbit around the hydrogen nuclei has a radius 1/200th as big as the radius of the electron's orbit. The muon is also short lived. After a few microseconds, it will decay into other particles.

Some of the earliest theoretical work in the field was done by FC Frank at the University of Bristol based on experimental evidence found by Lattes, Occhialini, and Powell both in 1947. None other than J.D. Jackson of "…

Secure Facebook Apps on Google App Engine

A few weeks ago, I asked a friend of mine if he'd mind testing a Facebook app, (MapMyFriends) that I was working on. It's a simple little app that maps the locations of your Faceboook friends on a Google Earth plugin. the app has grown and now it will fly you through a global tour of all your friend's photos displaying them on the globe where they were taken... But I digress.

My buddy came back with the rather unexpected response that my app wasn't setup for secure browsing on Facebook and he couldn't see it at all. This led me into a few days of work to make the app secure. I've included my notes below in case you run into the same issues I did.



First: It's not difficult
You'll find lots of documentation on OAuth 2.0 and user authentication, but at the end of the day you probably don't need it. You've already setup account login however you want it in Facebook right? If all you want is an application that communicates back to the Googl…

Venus Transit!

The transit of Venus across the sun is coming up on June 5th! If you would like to go to a viewing event in your area, NASA has setup a handy map for you to locate an event. For ham radio operators, there are plans to collect transit data via APRS.

For everyone that's interested, you can learn more at the following links:

NASA school workbook on the mathematics of the transit [pdf]

The workbook doesn't have an explanation of parallax measurements. It turns out that Parallax is more than just a comic book character. It's the process by which you can calculate the distance from the earth to the sun using transit data. Wikipedia however, has a great page on parallax.

Finally, there is a smart phone app for recording transit data.
Picture of the Day
From 6/4/12

The Javascript Google URL Shortener Client API

I was working with the Google API Javascript Client this week to shorten the URLs of Google static maps generated by my ham radio QSL mapper. The client interface provided by Google is very useful. It took me a while to work through some of the less clear documentation, so I thought I'd add a few notes that would have helped me here. First, you only need to authenticate your application to the url shortener application if you want to track statistics on your shortened urls. If you just want the shortened URL, you don't need to worry about this. The worst part for me was that the smaple code only showed how to get a long url from an already shortened rul. If you follow the doucmentaiotn on the insert method, (the method for getting a shortened url from a long one), there is a reference to a rather nebulous Url resource required argument. It's not at all clear how to create one of these in Javascript. The following example code shows how:
var request = gapi.clie…