What I Learned Today

“I’m looking for a book on trees.”

I blinked up at the library patron and experienced a moment of mental white-out. Almost, but not quite as bad as, “I’m looking for a book with words in it.” Since she seemed to expect some sort of response, I asked, “Ah… what kind of trees?” and we launched into a mini-game of 20 Questions that ended with me finding “Trees and Shrubs for Dummies” and her walking away beaming happily. Strictly speaking, though, I was breaking the rules.

I’ve been volunteering at the library since May, helping out with shelving books, re-barcoding books, sorting donations, and helping patrons with computer questions. Last week I was officially designed a “Tech Volunteer” and given a seat at the Adult Reference desk, next to the (real) Adult Reference Librarian. My areas of capability are clearly delineated: I am permitted to assist patrons in any way with computer questions and I can guide them in their OPAC computer catalog searches — but only if they are doing an Author or Title search. Subject searches, I was told, are more complicated, and for that I should direct patrons to the actual librarians. So yesterday I sat at the desk, a pile of books before me to bar-code, and every 30 seconds I would look up to see if any of the patrons at the 20 library computers before me were in need of assistance (I am getting very good at visually assessing this). Every five minutes or so, I’d get up and physically wander through the area, since this often elicits questions patrons otherwise don’t feel like getting up to ask. I helped with login questions, printing questions, and even one patron’s request for a “unique identifier” that she could use as a screen name. Given some coaching, she settled on a name — then came back two minutes later for help in picking a “tricky” password. I managed to give her tips on how to do this without her actually telling me what she came up with (whew!). And after each person I helped, I got to increment the tally on our official Reference sheet for the day.

At any rate, I had my station at the Reference desk, complete with a little sign that says “Tech Volunteer on Duty” that I get to put up to advertise my capabilities. But then the OPAC database access went down. It’s still not clear exactly what was wrong (and it’s still broken today). Patrons using the catalog computers could get a list of results by “Browsing” authors or titles, but clicking through to an individual book title yielded “title not found.” Keyword searches returned zero hits. Our library is small, but it does have more than one book with “Lewis” as the author name. So what do you do when the catalog fails? You go to the Reference desk! And from the patron view, I was apparently indistinguishable from a Real Librarian. Both of us were suddenly inundated with patron requests. One good thing was that our two computers, which use a different program to access the catalog, were still working. So I puzzled out how to look up books, check copy status, browse related subjects, etc., through the new interface, to help field the questions we were getting. Nothing like learning on the fly!

And let me tell you, they were right: figuring out what book is wanted by doing Subject searches *does* require some advanced skills, like being familiar with the Library of Congress subject listing (which now comprises six printed volumes!). Nothing is based on words actually in the content of the books, only what predefined subject tags have been associated with them. If you don’t know the tags to use, you can’t find anything. Sitting at that desk was like being on a quiz show.

“Do you have a book on resumes? One with examples so I can just fill in the blanks?”

Mostly this was fun (but somewhat adrenaline-rushy), except for one particular episode. A gentleman approached with, “Where are your cookbooks?” I replied, “I’ll look that up for you.” He said, “What, you don’t know?” I located the section and escorted him to it. “I didn’t bring my glasses,” he said. “Could you find me a slow-cooker book?” I scanned through three sections and triumphantly handed him three such books to select from. He picked one, and then I made my mistake. “Can I help you check that out? I’d be happy to show you how to use the self-check machine.” He grinned and accepted. As we walked across the library, he launched into, “Where did you go to school? How old are you? Are you single? Live by yourself? I have two single sons in their mid-40’s.” I was totally taken aback, trapped between the library customer-service mentality and a cringing horror at what was issuing from his mouth. I showed him the use of the machine and escaped as quickly as I could. How do you tactfully indicate to someone that they are overstepping the bounds of politeness? Maybe library training needs to include advanced social maneuvering as well.

Overall, though, I was able to help several people and, given the OPAC problem, I felt that my presence made a difference. Not bad for diving in! Even if I broke the rules by helping with Subject searches.

Today, I was off the Reference desk hook and instead shelving Juvenile fiction. But I stopped in to say hello to the Reference desk librarian, and then as I was leaving, I heard a patron ask her:

“Do you have a book on history?”

She answered, “What period of history are you interested in?” and I smiled as I walked back to the children’s side of the library.

One of the challenges to be met and conquered during my upcoming mission to Mars is the limitation on showers. We have a very limited supply of water for our mission, just 39 gallons per day to support six crew members. We anticipate this supporting only one shower per day, so we’ll have to rotate through and wait six days between our individual showers. I don’t think I’ve gone more than three days between showers since reaching my teens, and those gaps have been few and far between (camping trips). The crew briefing documents recommend bringing baby wipes to facilitate sponge baths between showers. But now I’m stuck wondering: what about my hair?

It’s not the appearance that I’m particularly worried about, and my hair is actually rather short, which probably makes this easier than it would be otherwise. It’s just that I’ve observed that going even 1.5 days between showers leaves my hair greasy enough (to me) that I don’t want it touching me. I don’t like the hair oil smell. (Does this mean I’m over-civilized? Or is it true that daily showers make your hair produce more grease than “normal”?) I have no idea, but eventually I confessed my worries to my hairdresser and asked her advice.

“Take a dry shampoo with you,” she said.

A dry shampoo? What? I’d never heard of such a thing. It turns out that dry shampoos are powdered substances that perform the same function as the liquid shampoo you’re currently using: they bond to the sebum (oils) in your hair, and can then be brushed out, carrying the oil (and any dirt or other particles stuck to the oil) away. The efficacy is generally lower than that of a wet shampoo (probably due to easier distribution and bonding in liquid form), but apparently still can provide a good between-shower cleaning. Just the ticket for a restricted water environment!

The dry shampoos available commercially seem to be rather expensive ($20-25), but the web is teeming with advice about making your own from corn meal or cornstarch or salt or clay or what have you (plus baking powder, to absorb odors). I think it’s worth a test run prior to the mission. If it works, I’ll be set! Nothing like low tech solutions to save the high-tech day.

In reading “The How and Why of Mechanical Movements,” I’ve gone from levers to linkages to wheels to pulleys to screws, plus a really fascinating discussion of friction and its use in machines. One of the cleverest devices I’ve seen so far is the differential pulley or differential hoist, used in auto repair shops and factories to allow humans to lift very heavy loads (like car engines).

The differential pulley is composed of two pulleys with different diameters mounted on the same axle. The rope (or chain, with toothed pulleys, to prevent slippage) is looped in opposite directions over the two pulleys, with the weight to be lifted suspend from one downward loop. If you pull on the other (unloaded) loop hanging down, relative to the larger-diameter pulley, then for each meter of rope/chain it releases, the smaller pulley must take up fractionally more rope/chain, yielding a net lift for the suspended weight. The diameter difference means that you had to pull more rope/chain than the distance the weight was lifted, yielding a mechanical advantage (i.e., you don’t have to pull as hard, you just have to do it for longer). This is difficult to explain in words, and much easier to grasp from a diagram; click the image at right to enlarge it. (I personally found the differential windlass, which was a precursor to the differential hoist, a useful aid in understanding the latter.) At first it seems counter-intuitive that the weight should hang suspended without pulling the second loop tight as well, until you observe that the key is that the two pulleys share the same axle and are wound in different directions. Thus the weight pulls equally on both sides of the axle and it does not turn, until an additional force (your hand) upsets that balance. (All drawings are from A First Course in Physics, by Robert Andrews Millikan and Henry Gordon Gale (Ginn and Company, 1906), as cited in Donald Simanek’s lecture on simple machines.)

If it wasn’t obvious, I’m really enjoying this book (and learning a lot). The current chapter just covered automobile clutches and brakes and several different kinds of bearings. The next chapter moves on to gears and transmissions (actual automobile transmissions, manual and automatic). Given its richness and re-read value, I’m likely to want to keep this one much longer than the library permits. Amazon to the rescue!

It’s easy to get something to move in a circle; just pin one end down and rotate the rest (like the kind of compass you draw with) or pin the center down and rotate (like a merry-go-round). But how do you get something to move in a perfectly straight line, as is needed, for example, in engines with pistons? I’m reading a delightful book from the 1960’s called “The How and Why of Mechanical Movements,” and the subject of straight-line motion came up in chapter 2 (Levers).

It turns out that a clever arrangement of a collection of rigid bars, connected into a linkage, can give you this magical straight-line motion. Various inspired inventors have come up with different ways to achieve it, and their concepts are illuminating and fascinating.

There’s Watt’s linkage, which requires only three links. It doesn’t quite produce perfectly straight motion (note path of the red point in the animation at right), but good enough that it was used by early steam engines. It’s still used in the rear axle suspension of some vehicles, so that no sideways motion is permitted between the body of the car and the axle (the axle only moves in a vertical straight line with respect to the car body).

The Chebyshev linkage (below left) likewise uses three links and achieves a straighter line, within a prescribed range. In 1864, the Peaucellier-Lipkin linkage (below right) was invented, and it even comes with a proof of collinearity. (These animations are awesome!)

The authors of “How Round is Your Circle?” (another book that looks absolutely engrossing) have an excellent supplementary website. One page shows some beautiful physical incarnations of the almost-straight-line linkages as well as the truly straight-line linkages (check out the videos!).

And now, I’m off to read about more fabulous mechanical movements and be awed by others’ ingenuity.

It has always seemed a little unfair that, in the midst of trying to fight off a flu, you would be beset with aches all over your body. What purpose could aching really serve? The only hypothesis I could come up with was that it was a signal from the body to the brain: “Hey, I’m busy fighting a war in here, please divert all possible energy to the production of white blood cells and temperature elevation, and stop trying to walk around.” But once you’re collapsed on the couch, eyes swimming too much even to read, then really, what’s the point in that signaling system continuing its torture?

As usual when googling to learn about any sort of medical symptom, you can find sufficient material to send anyone into a hypochondriac frenzy just based on “body aches.” They could indicate that you are suffering from stress, depression, or even pregnancy! (No, not really. :) )

But back to the why: body aches (myalgia) in the case of the flu are caused by the body’s self-defense functions. According to Richard Deem (Cedars-Sinai Medical Center), macrophages attack diseased cells, producing inflammatory interleukins (especially IL-6, and that inflammation manifests as an aching body. So the aches just mean that the defense system is active—and the bad cells are being weeded out.