Kite video attempts

I tried attaching a camera to a kite and recording video but there was not enough lift to keep it in the air.  I ran a short distance to try to get it high enough to catch stronger wind.  Above is my first attempt and below is the second.

An old chair

Here is another item of free furniture.  A wooden chair painted in white.

Underneath the seat is a label, Tarm Stole Møbelfabric.  By the way, "fabric" means "factory" in German and I suspect it has the same meaning in Danish.  

There is also a "Made in Denmark, 1   9  8 4" stamped into the wood. 

You might be able to see the stamp in the picture above. 

The problem with this chair is the legs keep working their way loose and falling off.  This is exasperated/exacerbated (they both mean to intensify and annoy...) by M's habit of leaning it back on two legs.  I have glued it back together several times with carpenter's glue.  V suggested I throw it out but it has kind of turned into a running joke to see how far I can keep it stumbling along.  In the latest iteration I used a turnbuckle, plumber's chain, and some S-hooks to help hold the legs together, and so far it seems to be working. 

The Future Party

A big problem with American politics are short term fixes that are penny wise and pound foolish.  What if we put together a political party that focused on the long term picture solely to invest in the future of the US⸮ 

I am all for individual self-determination, rights and freedoms, but this doesn't mean we can't take part in collective actions--that we can not do alone--if we decide to do so together as a democracy.  The best way to start long term investment in the future of the country is to promote education, health care, and reduce debt.  Another component is to promote a sound economic infrastructure, like rail travel, renewable energy and basic research. 

How to encourage politicians⸮  What if we pegged politician retirement income and benefits to the median income, updated yearly, of US citizens (or people living in the US, not just citizens, whichever is lower)?  Also, what if we spread out terms over a longer time period so that politicians could not serve consecutive terms but could serve alternate terms (perhaps at half the time span, elected once and serve twice over a longer period)?

Icosidodecahedron

Six wire loops can be combined to make a projection of an icosidodecahedron onto a sphere.

http://en.wikipedia.org/wiki/File:Icosidodecahedron.png

 
I've been playing with a simple way to approximate a sphere with the least copper wire and the smallest gaps in between for some possible future electrostatic plasma experiments.  Of the platonic solids the best sphere approximations are the dodecahedron and icosahedron.  However, the icosahedron has five edges that meet at each corner, which seems like a waste of wire in a dense area.  Ultimately, I think the best approximation will be a « soccer ball » truncated icosahedron; however, that can not be made with simple loops of wire.  This pattern, the icosidodecahedron, is interesting; it combines an icosahedron and dodecahedron together.  If you dropped out the five sided faces and pushed everything together it would be a icosahedron; if you dropped the three sided faces and put the rest together it would be a dodecahedron.  By combining the 20 sides of an icosahedron and 12 sides of a dodecahedron we get an archimedian solid, the icosidodecahedron.

Rescued Coffee Table

Here is another one of our finds: a coffee table that was being thrown out.  I cleaned it up, tapped nails back in that were working their way out (with a hammer we found that was also free), and am half way through oil treating the wood in the picture above.  The top is made from a single broad board. 

Weekend Update

M and I saved up styrofoam blocks from packages going all the way back to Christmas.  We taped them to a cardboard base to make a target for her to practice with.

Then we went to "round top" an overlook above Honolulu.

Then we washed the van, but first a before shot showing our chalk work, math and art, on the driveway.

A clean car and soaked kids!

Planetary Resources

Here is an exciting news article (link). 

Planetary Resources plans to send up some telescopes to look for asteroids to mine for a profit.  Asteroids can contain tremendous amounts (compared to earth surface standards) of valuable rare metals.  By the way, the price of platinum, gold, palladium, etc. might crash over the next few years...  Just finding and reporting the contents of an asteroid, before actual mining, may make the markets realize how much is available up there.  Also having common items like water (or even dirt) in space is valuable for space use because it doesn't have to be transported off the surface of a planet.  Wow, V can verify that for over a decade I have suggested private companies need to start doing what the government isn't: space exploration and specifically asteroid mining.  It is a positive move forward to begin building a space based economic infrastructure.  I wish I could be a part of it somehow.

Geiger Counter, § III

I wanted a reliable radiation source to test out the geiger counter.  As I have discussed in earlier posts, I haven't had much luck with vaseline glass.  Either it turned out to be fake or I can't get it shipped here from the EU.  There has essentially been no vaseline glass production in the last 50 years (since the beginning of the cold war); everything out there is an antique.  Vaseline/uranium glass is easy to find for sale online but can cost several $100's because they are sought out by depression glass collectors. 

So I switched strategies and went straight for the source, uranium ore.  There are mines all over the western US from Texas to Washington and it is easy to order small pieces through the mail for testing; you've got to love the US!  Otherwise we would be forced to get our radioactive material the old fashioned way, by stealing it from « nationalists » and getting chased around mall parking lots⸮ 

Just for the record, I am keeping it doubly sealed and stored out of reach.  It is a harmless amount of radiation when kept this way.  I can help illustrate this below.

In this picture the ore is right against the tube, which just registered 306 counts per minute.  The reported activity for this fragment is 600 CPM but this tube does not detect alpha particles.  I am leaving the ore in the plastic bag to minimize possible dust contamination. 

In the graph above I've converted CPM to μSv/h (micro-Sieverts per hour).  The highest point, 4 μSv/h, corresponded to just over 500 CPM--for this particular GM tube.  It was singing away at almost 10 chirps per second!  But first let me explain, the initial low level in the plot, below 0.5 μSv/h was to establish a background level of radiation.  Then the sharp rise to 3 μSv/h came when I put the uranium ore directly against the tube.  Then it jumped up and down as I rotated the ore to find the hottest spot which seems to be somewhere near 3 - 3.5 μSv/h.  I left it there for a few minutes then moved the ore 1 cM away from the tube, and the signal dropped to 1.5 to 2 μSv/h, then I moved it 2 cM away and it dropped to 0.5 to 1 μSv/h.  I kept doing this until it was back down to background levels with the ore >10 cM away.  (Because of the sensitivity of orientation what I really should have done is fix the ore's position and moved the tube's distance, but the important point remains.)  If the ore is not immediately next to you, there is essentially no increase in radiation.  Just being in the same room, for example, has no effect.  The rapid drop off comes from the radiation spreading out in the a sphere, which grows rapidly and dilutes the strength, as distance increases by small amounts. 

To put this in perspective, the doses from a chest x-ray, mammogram, or GI x-ray range from 2,000 - 18,000 μSv.  To get a dose of 10,000 μSv you would have to carry the ore in your pocket for 119 days.  In fact carrying it around for an entire year, still keeps you under the maximum yearly limit of exposure (50,000 μSv) at maximum exposure orientation.  The yearly limit is off the scale above at 5.70 μSv/h when converted to a per hour unit. 

The only real potential danger is if fragments were ingested or inhaled.  Then almost all of the emissions are absorbed over an extended time-period.  So it is my job to ensure that that will not happen. 

Speaking of ingesting, how many bananas do you eat in a year⸮  Bananas are rich in potassium, which naturally includes the radioactive K-40 isotope.  The maximum exposure I measured above, if maintained for an hour, is in some ways similar to the total dose received from eating 35 bananas.  I am not trying to say that bananas or other foods rich in potassium are dangerous; I am just trying to put the exposure levels involved here in perspective. 

So now I have a reliable source to test with that is strong enough to give a clear signal but is still within safe levels of exposure. 

Fun with the vacuum pump

I picked up some 3/8 inch braided reinforced tubing from the hardware store.  (It said self service on a sign so I cut a 3 foot section by measuring it on my arm, but the cashier said we were supposed to ask for help and denied that it said self service at the hosing section...?  Anyway, I got it cut to exactly 3 feet when she measured it.)  I also picked up a nylon hose barb and a "lavatory Pop-up Gasket: Fits American Standard" Stock No. 34621B in the kitchen repair section to go over the end; it looked about right and turned out to fit perfectly. 

Then we found and cleaned a sturdy large glass bottle and dropped a bunch of small "hot chocolate style" marshmallows in it. 

My laboratory assistant stood at the ready with her safety goggles on. (T also played with the pump a bit but was not around when I took the pictures.) 

Just before starting the vacuum. 

The marshmallows swell up as the vacuum is drawn, because of the air bubbles trapped within them.  (I know it doesn't look as dramatic in pictures, perhaps I should try to catch this on video.)

Then they shrink up wrinkled as the vacuum seal is broken and the atmosphere crashes back down on them. 

Population Sizes and Chaotic Music

Let's think about a very simple model of population growth.  Say at any given time the popualtion is at some fraction of the total possible, like 10%, 50%, or 90%.  We can represent this as 0.1, 0.5, or 0.9 respectively.  The current population can grow at a certain rate, r.  Let's say the current population fraction is x.  We can multiply r and x to get the size it has grown into in the next generation.  Let's call the next generation x'.  So we get a simple formula, x' = r x.  If r is 1 the population stays the same size (on average each individual produces only one descendant for the next generation).  If it is greater than one the population grows in size.

OK, the population can not grow past 100% of its total carrying capacity.  So if it gets too large and uses up all the resources (food, shelter, etc.) the population will shrink (die off) by some amount.  To take this into account we can multiply (1 - x) --the distance the population is from the maximum size--in our model.  So now we have x' = r x (1- x ).  This is a very simple formula to model population growth, but it has some very interesting properties.

Now, if the growth rate is only 1, r = 1, the population declines in size because some resources are used up.  With a growth rate of two the population approaches an equilibrium at 50% of its maximum size; it doubles each generation but half of the resources are used up, cutting it back in half again.  What happens with an even higher growth rate, 2.8.  (An average of almost three offspring per adult.)

Now the population overshoots the equilibrium a bit.  When the population size is low there are plenty of resources and a large number of offspring, but the large number of offspring means even more resources are used up in the next generation and so there are less surviving offspring.  The population size oscillates for a few generations until settling down on an equilibrium value.  (This is called a dampened oscillation.)  What happens if the growth rate is even larger?  

With an average of 3.3 offspring (6.6 per couple) the population approaches a stable oscillation.  It uses up too many resources, crashes, rebounds, uses up resources, crashes, rebounds, ....   At equilibrium it alternates between two sizes, like over-correcting while steering a car or bicycle. 

At an even higher growth rate, r = 3.55, another shift in behavior occurs.  The population is still oscillating in size, but it takes four generations to return to the same point.  It is as if the population overgrows a lot, crashes by a huge amount, grows less from the lower number, crashes less from the lower peak, overgrows a lot, ...   Importantly, though, trajectories starting from slightly different values still converge to the same cycles (in the figure above one population starts at x = 0.1, blue, and the other is x = 0.15, orange, in generation 1).

Some organisms can have 100s of offspring.  What happens if we raise the growth rate even more? 

After a certain point we encounter chaotic behavior.  The changes in size do not follow an obvious pattern and small differences in starting values result in widely different, divergent, trajectories a few generations later.

However, it is important to keep in mind that these changes are not random and are solely determined by the simple equation, x' = r x (1- x ). If we plot x' versus x, from generations 5 to 40, we see that the points jump back and fourth but fall along a simple curve and start to fill in something like a inverted parabola shape.

If we plot the equilibrium point(s) that are approached by x (the population size) over a range of r (the per generation growth rate) we get this type of diagram.

So, as in the examples I illustrated above for r = 2.7 a single equilibrium value of x is approached.  For an r = 3.2 the system tends to oscillate between two points.  At  about r = 3.5 it moves between four points.  Then briefly as r increases there is an 8 point oscillation (and if you look closely at the r = 3.55 example above you can see it is actually visiting 8 points rather than 4 I said above) and after this point it quickly becomes so complex that a wide range of points are visited and we get chaotic behavior.  However, you can also see gaps in the chaos where the system suddenly settles down and oscillates between only a few points before becoming chaotic again.  This is the classic bifurcation diagram of the logistic map in chaos theory. 

So this is a complex system but there is a relationship between nearby points in time, kind of like the notes in music.  (A search online shows I am not the only one to think about this, here is an example).  I've been curious about this and finally got around to converting x values from 0-1 to a MIDI file with notes in an octave scale.  The MIDI can then be converted to WAV (http://www.hamienet.com/midi2mp3) and sheet music (http://www.8notes.com/) formats online.

The first example moves along the logistic map.  I slowly increase r each generation and let x (sound pitch) follow along.  You can hear the notes growing, then oscillating in a simple pattern, then more complex, then chaos, settling down into a simple pattern again, then back to chaos.  I'll put the logistic map here again to follow along.  As the music plays follow the curve from left to right. 

Yes, I know it is a bit maddening to listen to (V made that clear to me when I was tweaking the sound and playing it over and over at home earlier), but it also has some interesting points and I dare say is not the worst music ever made (certainly not the worst I have made). 

Next is an example with two notes generated with two different fixed values of r, 3.6 for the lower note and 3.9 for the higher one.  It sounds demented but there are some textures that fade in and out near the middle of the recording. 

This could be further modified by varying note duration, etc.  ...

Geiger Counter, § II

❦ I needed a Geiger–Müller tube to add to the Geiger counter board.  The tube has low pressure gas in it between a high voltage anode and cathode.  When a particle of ionizing radiation passes through it it hits a gas atom and creates a + and - charged particle pair by knocking off an electron.  The pair race towards opposite ends of the charged tube.  Along the way they accelerate enough to knock other ions loose, which knock even more loose and create a cascade of charged particles.  This amplified signal registers in the circuit and is what allows single particles to be detected.  I found a J305 beta/gamma tube for sale for $31 by a company in China.  When the package arrived it had been checked by security.

❦ This tube can not detect alpha particles (helium nuclei), which are stopped by the glass.  But it can detect beta (high energy electron) and gamma (high energy photon) particles.  To try it out I temporarily connected it to the geiger counter shield which was plugged into the micro-controller underneath, which was connected to my computer.  I uploaded a program found here (link).  ☞ Note the conversion factor must be set correctly in the program for the model of tube you are using. 

❦ It clicked every few seconds and in the picture it registered 12 counts in the last minute (CPM, counts per minute), which, for this tube's sensitivity, corresponds to 0.0974 micro-Sieverts per hour of background radiation.

egamI rorriM | Mirror Image

❦ It is funny how little details of our daily lives influences how we see and think about things. Our notion of up and down is a very powerful influence. My brother used to ask all kinds of hard to answer questions, such as "Why do clouds stay clumped together and not spread out like smoke in a room." Our idea of horizontal and vertical seems equivalent. You can just rotate something 90 degrees and switch between them. But there is a subtle difference. One time my brother pointed out to me that horizontal planes can not intersect while vertical ones can; I had never thought about it before. Horizontal has a stricter definition than vertical. We could make up new vertical definitions like vertical-away and vertical-across to discriminate between types of vertical planes. Say we are facing north, then vertical-away planes that are along north-south lines can not intersect. Similarly, vertical across planes that are on east-west lines can not intersect either, like horizontal planes.

❦ Here is another simple question. Why are words reflected in a mirror flipped right and left, but not up and down? Think about it for a moment; it seems strange.

⁂ 

❦ I was thinking about this mirror image problem on my commute this morning and got the idea for this post. I think this is also related to our notion of up and down versus right and left. The mirror isn't really flipping anything. What is closer to the right is closer to the right in the image, what is higher is higher in the image, etc. It seems flipped because we imagine it as looking through a piece of glass at the image on our shirt, but to do this we would walk around to the other side of the glass and face ourselves (not face away in the same orientation). We imagine up and down remaining the same and that we would rotate left or right, on a vertical axis, which exchanges left and right in the word orientation. However, if we were talented enough, we could also get to the other side of the glass by flipping over it and landing on our hands upside-down to face back towards ourselves. If we were used to getting around and looking at things this way then the mirror image would instead appear upside-down reversed to us.

❦ This is a bit of a tangent but I used to work in a printing press darkroom.  Among other things I would develop film images of magazine articles.  There was not much else to do so I would read the articles while waiting; however, the film was often reversed in the solution baths.  I got so used to reading reversed text that after a while I had to stop and think for a moment if text was in the right orientation or not.

Geiger Counter, § I

❧ A few weeks ago I mentioned hooking a portable geiger counter to a drone as a way to measure radiation levels in dangerous areas.  Also, radiation from the 2011 Japanese Tsunami and Fukushima reactor damage is being monitored nearer to Japan and projected to be drifting across the Pacific nearer to Hawai'i.  There are some reports of small spikes in radiation levels at a monitoring station in Kauai.

❧ Not to sound alarmist, these are low levels of radiation here and probably harmless.  Aside from the Fukushima nuclear disaster, it would also just be fun to have a geiger counter to play around with.  Also, I was thinking of some higher voltage experiments with our
« new » vacuum pump and would like a way to monitor for x-rays.  Libelium electronics in Spain has been working on a cheap, portable geiger counter to help people in Japan monitor radiation levels.  The models with the Geiger–Müller tube included have been sold out, but the circuit boards are still available.  I ordered one and it came in the mail!  Basically the board is a shield that plugs into our Arduino microcontroller.  It has a transformer to convert the 500V required for a GM tube, and a speaker and LCD display to show the results. 

⁂

❧ Libelium also had an option of shipping a vaseline glass bead as a low level radiation source to test the geiger counter.  Since my vaseline glass find turned out to be fake I requested the glass bead.  However it was not included in the package with the circuit board.  Instead was a letter that said,

"La empresa que suscribe ante administracion de aduanas manifiesta:

Mediante presente escrito certifica que la mercancia amparada con nuestra factura ... que viaja bajo albaran ... no son productos de doble uso y no estan incluidos en el Anexo I del Reglamento (CE)№428/2009"

❧ Apparently the glass beads are considered « dual use » which implies they could have both a civilian and military use and are thus restricted from export out of the EU under regulation 428/2009.  I looked through the regulation document (link).  It mentions enriched uranium and depleted uranium, but I don't see anything about restricting trace amounts of natural uranium used to color glass beads.  Seriously, this is an absolutely harmless level of radiation.  What is Spain worried about, that the US will use glass beads to start a nuclear program⸮

-----
Update: a relative of mine helped me precisely translate this and it seems that I have confused a negative.  It thought it said no double use products could be included and that it was not included in the shipment because it was in 428/2009, but I am told that this actually says it is not in 428/2009 and thus not considered dual use.  This is even more confusing because they did not ship the glass beads.
-----
Another update: Now I get it; the current shipment, without the vaseline bead, is in compliance with 428/2009.  So the issue still stands, apparently vaseline glass can not be shipped out of the EU...?

Caine's Arcade

A fun story about a kid that made his own arcade.

Wooden Bowl

Here is a large wooden bowl we salvaged recently.  It was pretty dull and dirty but I scrubbed it down with tack cloth and linseed oil this morning.  V is planning to use it on her desk to keep keys and change in. 

By the way, there was a sandwich in Germany that used Wikinger bread made with linseed (flax) and sesame in the flour.  It was very filling and tasted wonderful.  The smell of the linseed I used on the wood reminded me of the Wikinger bread in Germany. 

Dodecahedron

This morning before heading off to work I tried putting together a copper wire dodecahedron (12 pentagonal sides) one of the the platonic solids.

It is pretty rough with the angles off, like it got squashed, but not too bad for eyeballing 12 sides together.

One curious thing about dodecahedron's is that small bronze ones with holes in the center of the faces have been found in Roman sites but there is no record as to what they were for.

The triangle, square and pentagon can curve back on themselves to form these 3D shapes.  The next shape up, the hexagon won't fold back in on itself but forms a flat sheet when (regular) hexagons are placed next to each other.  Here is a photo of all three wire creations thus far. 

I am thinking of hanging them by string from the ceiling.

Stepper Motor Driver

Another task with the stepper motor setup is how to control it.  A driver is used to convert input (step and direction) to the correct signal sequence in the coils to turn the motor.  It also provides power which in this case is 12 volts.  I ordered an EasyDriver and hooked it up in a breadboard to the motor on one side, 12V power on another, and input signal from the Arduino microcontroller on the third side.  In turn the Arduino is connected by a USB cable to my laptop to upload programs.

I uploaded a simple program to turn 10 steps in one direction, then 10 steps back, etc.  There was a problem.  The motor turned one way but with a click, then jiggled and wouldn't go back.  I am sure my freezing, heating, hammering, etc. trying to work out a coupling system ruined it.  So now I know exactly what not to do.  At this point there was no reason not to open it up and take a look.

The center has magnets and a toothed wheel that lines up with teeth in the electromagnet coils around the outside.  It is these teeth that have very precise tolerances and can get chipped or bent.  I tried moving things around a bit to try to fix it but it doesn't seem promising.  So the stepper motor project is on hold for the time being.

How to type special characters

❧  I've had a couple questions about how to type some of the punctuation marks I blogged about earlier.  Until now I've been copying and pasting them or looking up their html/Alt codes, which is awkward.  Shouldn't modern operating systems have an easy way to customize typing non-standard characters⸮  I looked for a better solution and found some free software, autohotkey.  You can do a lot of things with it beyond what I am mentioning here.  To work with the non-standard characters I used the unicode version from http://l.autohotkey.net/ .  Under Windows, create a text script in your Documents folder (the software asks to do this automatically the first time you run it).  Then add some key codes to the script.  I added these:

!?::Send, {U+2E2E}   ; percontation point
!1::Send, {U+203D}   ; interrobang
!<::Send, {U+00AB}   ; left guillemet
!>::Send, {U+00BB}   ; right guillemet
!a::Send, {U+2042}   ; asterism
!g::Send, {U+2767}   ; rotated hedera
!h::Send, {U+2766}   ; hedera
!j::Send, {U+2619}   ; reverse rotated hedera
!i::Send, {U+261E}   ; index
!)::Send, {U+30C4}   ; katakana sokuon
!o::Send, {U+0629}   ; ta marbuta
!p::Send, {U+067C}   ; ta with ring

Then paste a shortcut of the script into your Startup folder to automatically load when you start Windows.  The ! is the Alt key and what is after the colons :: is substituted.  This uses the Unicode designations for the symbols.  With this running if I press Alt-1 I get the interrobang, ‽, with Alt-i I get the index, ☞, Alt-) gives the ツ , etc.

Good for something

I found a use for these fake vaseline glass cups.  They have grooves cut around them that are perfect for bending copper wire into circles.  I used some 16 gauge antenna wire for the circles and 22 gauge finer wire to tie them together.  (This brings to mind an aircraft mechanic I met once that used wire to hold all kinds of things together; he even had a special tool to twist and tie off the wire.)  On the right is the result of three loops connected at equal spacing.  It is hard to see this from a flat 2-D image but the outline is the same as an eight-sided octahedron projected onto a sphere. 

The wire frame on the left (at top) is the result of four equally spaced loops and are what you get if you project a cuboctahedron (an octahedron with square faces, blue, added between the triangles, red and yellow; cube+octahedron) onto a sphere. 

Easter

Every since we lived in New York we have had a family tradition of hunting for easter eggs on Easter Sunday morning.  In Germany we didn't have a yard so I hid them around the apartment.  Also, we have a tradition of putting little toy animals in them instead of candy.  Today was F's first Easter!  F and M went hunting in our front yard (T said he was too old for this and slept in).

F is uncovering a mostly buried easter egg. 

Above M is sitting on a couch going through her easter egg loot.  We carried the couch into the driveway to clean it.  We got it for free; I mentioned it in an earlier post; some neighbors put it out on the roadside for garbage pickup.  It was covered in mud and dog hair.  I scrubbed it (you can see the brush on the arm) and cleaned and scrubbed and cleaned.  Then I sprayed it down with febreze and let it dry.  Then V and I wrestled it up the steps and into our living room. 

Above are the sisters on the couch.  F loves flopping around on it.

I stayed with a Greek family for a short while, while living in New York.  They showed me their tradition of tapping boiled eggs for luck on Easter so I have started doing this with the kids.  Each person picks a boiled egg and you tap them against each other, if yours breaks you are out.  Everyone with an unbroken egg keeps going until one person is left.  This year it came down to V and F.  However, F whacked her egg against the top of a box and broke it before V got to her with her egg, so there are two winners this year.

V also picked up some fresh flowers to decorate the house.  Our neighbors that are moving gave us a small bathroom waste bin that worked perfectly as a temporary vase for the flowers. 

And last of all, after sundown the power went off again.  But our solar charged battery was set up and ready to go so I plugged in a lamp and we listened to the radio.