wrath of the mailing list manager

Why don't people know how to remove themselves from mailing lists?  In every mailing list I've ever managed, there's been an easy way for members to unsubscribe themselves, and I've made that information available in every instance.  But still, people email the entire list asking to be taken off, even immediately after I've sent out the how-to-remove-yourself instructions.  Are people just lazy or incapable of reading?  Are they spoiled by always having other people remove them?  Is it harder to unsubscribe yourself than I think it is?

I make it a point to keep my mailing list involvement minimal; I'm an expert unsubscriber. Before Gmail instituted it's filtered inbox tabs for "social," "offers," etc., I had already unsubscribed from almost every offer or social media email, and filtered the remainder to automatically skip my inbox.

I guess it just bums me out that I try to keep my own email inbox clutter-free, and I do my best to allow others to do the same, both by informing them of how to unsubscribe and by not sending unnecessary emails.  I try to make as little work as possible for myself, and then other people send me unnecessary emails in abundance, related to mailing lists and otherwise.  People make work for me by not only cluttering my email, but by requesting that I do something for them that they can easily do themselves.


why do natural fibers burn but synthetic ones melt?

I was switching out the bobbin on my sewing machine, and looking for a white cotton one to match my new thread.  The problem was that I have two white threads: cotton and polyester.  Which one was in the bobbin?  I couldn't tell just by looking at it.

So I whipped out the matchbox and performed the tried-and-true burn test.  Anyone who's familiar with textiles knows that natural fibers like cotton and wool burn, but synthetic ones melt into a little blob. The thread on my bobbin burned, proving it cotton, and I went merrily on my way.

But then later I found myself asking: why do natural fibers burn but synthetic ones don't? Surely there must be a chemical reason.  Digging around on Wikipedia didn't reveal any easy answers.

First of all, let's lay down some definitions: natural fibers come from plant, animal or mineral sources. Common examples of plant fibers are cotton, linen (via flax), and hemp. Animal fibers come from a variety of mammals including sheep, goats, alpaca, and rabbits for wool and fur.  Silks are also animal fibers, and come from animals like silkworms and clams.  The most well known mineral fiber is asbestos; mineral fibers aren't used for textiles.

Man-made fibers break down into roughly two categories: regenerated and synthetic. You'll see the word artificial used as well, but it seems to have an ambiguous meaning. Anyway, synthetic fibers come from chemical reactions.  All the sources I've read talk about extrusion, but I think this is best explained with an example.

When I took organic chemistry, we synthesized nylon.  The very basic idea is that you have two chemicals, one floating on top of the other.  In between, a reaction creates nylon.  If you pull the nylon out, more nylon will be created, giving us a nylon thread. Here's a video example.  I imagine fancy machinery does this at a smaller scale to create the stuff we use regularly.

My understanding is that regenerated fiber is created with basically the same process, except one of the chemicals is a cellulose pulp from a natural source, like wood, bamboo, or seaweed.  Rayon, an "artificial silk," is one of the most common fibers of this kind, and is made from wood.

Now let's get back to the burn test.  Natural fibers burn in various ways, synthetic fibers melt, and regenerated fibers burn a little and melt a little—not terribly surprising.  But why does the distinction exist in the first place?

Cotton, linen, and other plant fibers are made mostly of cellulose, which has the ring-like structure shown below.  When cellulose burns, it takes in oxygen and puts out carbon dioxide and water.  As a balanced chemical equation: C6H10O5 + 6O2 --heat--> 6CO2 + 5H2O.  The output are gasses, so they just float away.  Ash that remains from burning anything is mostly made up of metal oxides, so I'm guessing it comes from the non-cellulose bits.

Cellulose, via Wikipedia.

Animal fibers are made of more complicated proteins made from carbon, hydrogen, oxygen, nitrogen and sulfur and are called polyamides.  I'm imagining that they have similar (if more complex) chemical reactions that result in carbon dioxide, water, and other gases, as well as ash.  Nitrogen gas (N2) is common in the atmosphere, and Ammonia, or NH3 might explain the odor associated with burning animal fibers.  Hydrogen sulfide (H2S) also has a bad smell.

Nylon is also a polyamide.  It contains a fair amount of nitrogen, and burning it produces the dangerous hydrogen cyanide.  What I really want to understand is the following line (from the nylon Wikipedia page) on the chemical structure of nylon: "The direction of the amide bond reverses between each monomer, unlike natural polyamide proteins which have overall directionality: C terminalN terminal."  I have only a vague idea what it means, and no idea if it's even relevant.

Really, I just need to corner a chemist and harass them until they give me some straight answers.  Or find a resource on the chemical reactions involved in burning wool, nylon, and rayon.  So far, I've no luck.


February books

If last month had the theme of poverty, then this this month's theme might be discovery. That said, I can't guarantee a theme for every month.  Unless you want me to make things up, and weave insubstantial connections to paint a pretty, if ephemeral, picture. Because that's kind of what I did this month.  Discovery?  Every halfway decent book is about discovery of some kind.  Sure, the science history and murder mystery might plug in nicely, but what's particularly discovery-like about a family biography?  Discovering your home in a foreign land?  Discovering human connections?  That's just blather.

A Short History of Nearly Everything 
I can see this book being great for folks who aren't scientists, but there's only so many times I can take being told how many zeros are in 1043, seeing numbers written like 1,000,000,000,000, or reading "one million million."  The science history (who discovered what under which circumstances) was interesting, but the science itself--the history of nearly everything--was less so.  (Sorry, Gwen!)

Still Life ★★
I haven't read a lot of detective books, probably in part to balance out the universe because my grandmother has read so many.  This was a delightful read--very human and slow in the way that crime dramas on television usually aren't.  Despite that, I ended up reading almost the entire thing in one day. I anticipate continuing to read this series, but I'll need to moderate myself.

Rain of Gold ★★
A beautiful non-fiction of two Mexican families immigrating to America and crossing paths; their union resulted in the birth of the author, Victor Villaseñor.  This was a book abounding in feats of strength, both physical and spiritual, and so much so that they seemed almost unreal.