Archive for the ‘Uncategorized’ Category

Polyacrylamide

Saturday, September 26th, 2009

dry-sphere

Several months ago, I ordered some “growing spheres” from Educational Innovations , since a) I had an idea I wanted to try out and b) they sounded cool.  It turns out that the idea didn’t work, so we can add this particular article to the “learning experiences” category.

The spheres are made of polyacrylamide.  I freely admit that chemistry is one of my weak points, but even I can understand that this stuff is very hydrophilic, that is, it likes water.  It likes water so much that it can absorb up to 300 times its volume in water.  This means that the spheres, when hydrated, are almost all water, and are therefore a bit unusual (read: interesting) to fiddle around with.

See (or not) what I mean?

See (or not) what I mean?

In the picture above, there is a ~1″ diameter polyacrylamide sphere on the wire stand.  If you brush the dust from your screen and squint a bit, you might see the outline where the light is bent slightly by the “skin” of the sphere.  This is not photographic trickery, incidentally.  I put a half dozen of the spheres into a pot of water and came back the next day – it is an unusual sensation putting your hand into a container and encountering invisible objects in the water.  Their presence is  easier to spot by shining a light through the container and noting that focal points show up opposite the lamp as the polyacrylamide focuses the light passing through it.

Traditionally, these spheres are used in gardening to slowly release water into soil, or in science class to act as a planting medium, with seeds placed among (not inside of ) the spheres so students can watch the roots grow.  I thought it would be interesting to germinate seeds inside this material.  If the roots could penetrate the polyacrylamide, one could get the illusion of a plant hanging in midair, and with a root structure growing through a homogenous medium rather than growing around a pile of spheres.  Alas, it didn’t work that way.

I am not a botanist, nor a horticulturist, nor a floriculturist, nor even a gardener.  I have a Pothos growing across my shelves, and that’s it.  Once at the Agway, I picked flower seeds on the basis of germination speed and time of year.  I ended up with dwarf petunias and Cardinal Climbers.  Both would grow, but not well.

The first question was: how to insert the seeds into the spheres.  It turns out that the behavior of the spheres is rather like that of water balloons: heavily informed by surface tension.  If you throw a hydrated sphere against a hard surface, it shatters quite dramatically.  My first attempt at making a cut into a sphere resulted in it splitting open along the axis of the cut like a grape.  Small cuts seemed more stable as long as they didn’t describe an arc of more than 15 degrees or so.

sphere-sizeNote that the spheres on the left are smaller.  This is a result of my submerging them in a mixture of liquid plant food and water; the polyacrylamide has a lower absorbtive capacity for the plant food than for straight water.

The problem with this attempt is that the spheres, as they dried and contracted, tended to spit out the seeds.

I wanted to put the seeds deeper into the medium, so I needed to make a tunnel of sorts.  Piercing the sphere with a probe left no perceptible tunnel, and pushing a seed into the sphere burst it.  I tried removing material with drill bits, and this worked but was still not very stable.  The best way I found was to use a drinking straw.  This left a cleaner cut with fewer stress risers than the drill bit.  Try not to inhale the plug.

seed-implant

This is a Cardinal Climber seed pushed into the tunnel left by the straw.  The tunnel shortly filled with water, since the interior structure of the sphere had been damaged and began weeping water into the “wound”.  The seeds would float out, if not pushed in to a “press fit”.

This method failed, as well, though it worked better.  Before the UV light and evaporation degraded the spheres, I saw shoots on most of the seeds, but they would run out of the sphere and then down the side, not penetrating the medium but just getting water from contact with it.  Ultimately, I was left with a combination synthetic and organic mess as the sphere contracted around the seed.

Seeds that can grow in clay might work for this, but I don’t think so; the polyacrylamide structure seems to fail when anything forces its way through it.

So I’m stymied.  The minimum order was 1250 spheres.  I still have more than a few left, enough, in fact, to fill a few cubic feet.   I’m keeping them in a dark drawer to prevent degradation, but I feel that there are potential uses for these beyond as projectiles.

(As a note to the more … creative … sorts, no, you don’t want to feed these to the dog, and you don’t want to put them down the drain, either.  Stomach acid and drain cleaner might destroy them, but I wouldn’t bet Fido’s life on it.)

Unnoticed Infrastructure 2

Tuesday, July 7th, 2009

Yesterday, I posted an article about unnoticed bits of old infrastructure.

Today, one of my co-workers removed what appeared to be a non-fuctional old thermostat from the wall of our office while we were cleaning up.  He was rewarded with a neverending blast of (very musty) compressed air, shrieking through the small hole in the wall that the “thermostat” previously covered.  Fortunately, the device could be replaced with little trouble, and resealed the hole.  I have little idea what the device did.  It looked like a metal strip thermostat, but I’ve never heard of a pneumatic circuit arrangement like this.

I was reminded of how this sort of thing can be important.  If people have to deal with an unfamiliar device in a hurry, bad results can, well, result.  The worst building fire in the U.S. was the 1903 Iroquois Theater fire in Chicago.  A combination of factors combined to cause the loss of over 600 lives, but one was the use of “bascule” locks on some theater exit doors.  These locks were a European type that were used very little in the U.S., and so few people knew how to open them.  The results of a crowd trying to get through a nearly unopenable door were unfortunate, to say the least.  As it happened, a man named Frank Houseman had a bascule lock on his icebox at home, and so managed to open one of the exit doors, allowing numerous people to escape.  The installation of “panic bars” on doors in U.S. public buildings is partially a result of this disaster.

(It is also worth noting that a passerby named Peter Quinn opened another door from the outside with tools he had in his pockets, probably primarily a screwdriver, allowing another 100 people to get out.  Always carry a pocket knife if you can.)

I’m also told that knowing where door wedges are is useful in case of a “rogue shooter” scenario.

Apologies for the grim post.  The shadow of the book The Pessimist’s Guide to History stretches long.  To this day I am uncomfortable above the 3rd floor in wooden buildings.  I’ll try for something lighter next post.

Unnoticed Infrastructure

Monday, July 6th, 2009

Being a bit of a (an?) historian, I am fascinated by the little bits of architectural errata that somehow escape updating as a given building is renovated.

vertical-switch-web

There are a few interesting things here.

1)  The action on it is a little confusing: it is currently off.

2)  It is a design I have never seen before, and I’m surprised at it.  This switch is outside, and yet has a hole on the top for the sliding switch.  I have to wonder about water coming in along the shaft.

3)  The switch looks to long predate the patio it is attached to.  The plaque in the background notes that the garden was redone in 1976, which is presumably the date of the patio’s construction.  The switch is probably from the 20s, when the building was initially built.  Presumably an electrician grabbed the box from the spares pile in the basement.

I never saw it until yesterday.  I’ve lived in an apartment overlooking this patio for 3 years and never knew how to turn on the lights out there.

Similarly, but better hidden:

detex-closed-web

This is in a back stair at work that nobody uses.  What is it?  Let’s open it up:

detex-open-web

Well, first off, it’s mislabeled.  Room 219 is way down the hall.  The lever bar in the box swings out from the bottom, and is split horizontally down half the length.   Up near the top of the slit is a tab.

The idea was to keep your security guards on their rounds.  The guards would carry a clock that accepted these stationary “keys” which, when pushed into the clock, would force the clock to punch the time and station number onto a paper or cardboard record.  The reason that these station boxes are still in the building is partially due to the fact that they are in out-of-the-way places.

harding-one-web

This one is in a roof service stair.

I assume that most of them have been removed.  Still, there are innumerable little artifacts of history layered throughout our lives.  I walked by this one a dozen times before seeing it, and it’s in a main hallway.

harding-two-web

Take a look around your environment as if it were the first time you were present.  People have been there before you.

Pride and Power (tools)

Thursday, June 18th, 2009

v8_cut_web

I have been dwelling on a philosophical conundrum this evening.  Being both Catholic and an admirer of C.S. Lewis’s apologetic works, I see merit in the belief that pride is the greatest sin, being the only sin that leads directly to others, putting self foremost.

What, then, does this mean for the pursuit of power in the form of tools with more capacity than one needs?  Tools that accomplish what you need to do fall outside the scope of this argument; I am thinking about tools that are likely more powerful (and stylish) than you need.  A homeowner probably won’t use a 1000 lb-foot gas-fired torque “wrench”, and a commuter probably won’t ever redline a V8 automobile, but both tools impel a visceral reaction.

(As my friends will attest, sooner or later, most any conversation with me eventually turns to cars.)

Is hot rodding your car motivated by pride or the desire for glory?  Often, I would guess, though there are certainly those who do it to learn, or out of a commitment to engineering excellence.  One could argue that people do not need 3000 horsepower drag cars, and yet the competition they represent has been hard fought for thousands of years by horseflesh, chariots, packet ships, Regency-era coaches, bicycles, wood-track cars, locomotives, and numerous other conveyances.  The nitromethane fueled cars of the dragstrip carry no cargo beyond their drivers and a parachute.  They cannot be viewed as dispassionate research into more efficient passenger and cargo movement.  Corn dogs and similar foods of enthusiasm seem to be inextricably involved in drag racing, for example, in a way that they are not in airline menus.  It is also worth considering the impossibility of routinely driving a vehicle capapble of 5.7G.  And yet, the struggle for more horsepower, more perfectly applied, leads to extraordinarily careful efforts in developing fuel delivery, chassis design, and aerodynamics.  Is there a way to dispense with pride and lust for glory in the automotive world, while retaining both engineering progress and enthusiasm?  Is this the right question?

I will say that the note of an old V8 simply sounds pleasant when driving over old country roads.  Is it because I sense the history behind the engine’s development and the concominant history of the buildings, billboards, restaurants, fields, I pass by?  If so, why would a young child smile at loud (probably fuel-inefficient) cars?  They undoubtedly don’t know about the Interstate Highway System, the flathead Ford, and the rest of it.  And yet, many kids really like powerful cars.  Perhaps it is simply that the hot car is an exception to the quiet norm, and a fun one at that.  Fun seems to be tied into the technical and historic appreciation of the car.

Enthusiasm matters.  “80 percent of success is showing up”, as Woody Allen put it, and you are more likely to show up if you care about the work at hand.  That crawling feeling in your stomach just before you punch the throttle, fire up the welder, or even as you make a final decision on the blueprints, says that you care about the result.  The child who smiles at the fast car might learn to work on his (/her) car a decade later, and the result of that work might well be a grin similar to that of 10 years previously.

I read somewhere that the fact that something is dangerous just means that it is powerful, and so it may be with the lure of that power.  It can be used to try to sate an unquenchable desire for glory, and it can be used to develop skills and knowledge, and have a little fun.  I can go to a gas station and buy a truly vast amount of energy in a 5 gallon can.  I could use it in my car to intimidate other drivers, to risk others’ safety out of some sense of power.  But it is worth noting that the desire for a more potent conveyance led to a situation, as P.J. O’Rourke writes, where “Forty years ago the pimply kid down the block, using $3,500 in saved-up soda-jerking money, procured might and main beyond the wildest dreams of Genghis Khan, whose hordes went forth to pillage mounted upon less oomph than is in a modern leaf blower.”  (WSJ,”The End of our Love Affair With Cars”, 5/30/2009)  Power to the people, indeed.

I suppose that the counter to pride in power would have to be humility, humility before the capabilities that we have.  I am glad to live in a world where I might commute further than many people, historically, ever traveled away from home.  I am also happy that work is ongoing to make that travel safer, less resource-intensive, cheaper, and faster.  All of these things make life better.  I shall have to remember that the power I have is a gift, and to shepherd it well, while also remembering that enthusiasm for the improved is very much a good, and only to be suspected when it turns toward enthusiasm for me.

What is it?

Thursday, June 4th, 2009

One of my co-workers, knowing my fascination with things mechanical, dropped this on my desk the other day:

it-1-orthog

it-1-rear

It took me a while to figure it out.

As a hint, the label on the end flange reads indicates that it takes 10 amps at 120 or 240 V, and there is one (optional) part missing.