Thursday, February 28, 2013

3 Tidbits on 3-D Printing

  1. I mentioned earlier this week that the FDA has approved 3-D printed materials for filling in skull fractures. Researchers are also looking at the possibility (meaning that they don't have FDA approval yet) for creating artificial ear lobes (open access!). So what's the next device in the medical arena? Noses would be an easy extension of this latest advance.
  2. While these advances in the medical field are leave you hopeful for the future, sadly, the boys at Defense Distributed always have something to offset it, in this case a new 30-round AR-15 magazine. I realize that sooner or later someone would want to use 3-D printing for these applications and that you can't put the genie back into the bottle, but the confrontational attitude expressed on their website (e.g, calling this new magazine the "Cuomo magazine" and wishing the Governor a bad case of herpes) bothers me more than a little.
  3. And while at times there seems to be little that 3-D printing can't do (or won't be able to do in the near future), Doug Smock at The Molding Blog suggests that too many people have been "drinking the 3-D printing Kool-Aid" (including the president) and that a touch of reality is needed amidst all the the hype.

Wednesday, February 27, 2013

Elephants and Plastics - They Go Together

The trade magazine "Reinforced Plastics" was tripping down memory lane and republished this photograph that was one it's first cover from September 1956:
The connection between the elephant and reinforced plastics is that the drum that the elephant was mounting was made from a newly introduced material, FRP, which stands for Fiberglass Reinforced Plastic, but is better known by the general public simply as "Fiberglass".

While we may all think that the elephant had no idea that it's photo was being used to support the burgeoning plastics industry, the elephant's thoughts may surprise us. After all, before plastics existed, elephants were killed just to acquire their ivory tusks for such important uses as billiard balls and piano keys. Without plastics, this photo certainly would not have happened (on so many levels). So the link between elephants and plastics is far more relevant than it first appears. Which is a good thing, because:
(Source)

Tuesday, February 26, 2013

Poly(aryl happy-face)?

I've never been a big fan of graphical content in Tables of Contents. To me, it's just a distraction. I'm able to quickly look at a the bold-word titles in a TOC and find what I want.

But it's fine if a journal wants to put them in. It's just that they must be up to the same standards as the rest of the text. Why lower them, such as in this case:
Are the happy/sad faces really that communicative? If the general public saw this (and with the ever growing trend in open access, the general public will be seeing a lot more of this), what would they think? That scientists are taking tax dollars for research and publishing cartoons? How long before a national politician makes political hay with something like this? This really has to stop. It's not making science more understandable to the public - it's making a joke of it. If these "funny" graphical pictures are such a good idea, why aren't there more of them in the rest of the article? No, this has to stop.

Monday, February 25, 2013

3-D Printing Medical Implants

The last time I wrote about 3-D printing, it was regarding a use that I was not pleased about - print a gun. But technology is usually neutral which means that good can come from it. And that's the case in a new report the world's first implantable medical device has now been 3-D printed. It's a piece of poly(ether ketone ketone), PEKK, (not be confused with PEEK - poly(ether ether ketone) [*] ) used in skull repairs.

This is no small accomplishment as the final product needs to survive sterilization, and osseointegrate - allow the bone growth mechanisms in the body to incorporate the new material. I've worked with osseointegrative materials before, but they were pretty obvious candidates - hydroxyapatite - a calcium phosphate material which is already pretty close in composition to bone. I had no idea that PEKK could be such a scaffold for bone growth. The skull is a nice place to start as it is easily accessible, and not prone to any of the weight bearing stresses that most other bones in the body are exposed to. But I'm am sure that somebody is already looking at moving elsewhere in the body.

This is the first entry in a whole new world of medical devices. What will be next?


[*] PEKK and PEEK (and others) are poly(aryl ether ketones), a group of high performance polymers that have benzene rings in the backbone, and then ethers/ketones between them. PEEK is the most common and has a repeat unit with 2 ether linkages (and hence 2 "E's" in the name) and a single ketone linkage (hence the single "K"), while PEKK is the opposite - 2 ketone linkages and a single ether linkage.

Friday, February 22, 2013

Maybe they should have settled...

Lawsuits (and even criminal trials for that matter) can be tricky situations in most cases. Even though you think you are right, there is still enough doubt that the other side thinks that they are right. Clear-cut cases seldom end up in court. Given this, the issue always comes up about negotiating a settlement. A settlement is going to cost you something, and that cost can taste extra sour given your convictions that you are right, but sometimes settling is the best choice. It's just that you will be left with nagging doubts about whether you should have settled or whether you should have stuck to your guns. You just never know for sure that it was the best choice...

Except in this case. The plaintiffs charged price-fixing against a number of suppliers of chemicals used in making polyurethane foam. All of the suppliers except one settled:
"In 2006 Bayer AG agreed to pay $55 million. In 2011 Huntsman International LLC agreed to pay $33 million and BASF Corp agreed to pay $51 million."(Source)
Those are not inconsequential sums of money, but at the same time, those figures would barely show up in the annual report, as these companies all have sales around 1000 times larger.

But as I said, all but one of the defendants settled. The last defendant, Dow Chemical, stood firm on their convictions and pressed on with the trial. The end result could not have made anyone in Midland happy - the jury found them guilty and hit them with a $400 million fine. The judge also has the option to triple this making it a nice sum of $1.2 billion. While this will all be appealed (never an easy process as appeal courts loathe overturning jury decisions, and are more likely to just reduce the fine), it's seems pretty clear that taking a bite of the settlement-humble pie might have been the better choice.

Thursday, February 21, 2013

Polyurethane Balls in Flour

Courtesy of The Urethane Blog, a US flour company (Wegman's) is recalling bags of flour because they may contain "blue polyurethane balls". I'm not sure what size the balls are, and consequently how noticeable they are. The balls are used in the sifting process, so I'm guessing that the mesh that was supposed to retain them broke and let them pass.

I doubt any serious harm would come of this contamination unless the balls are so small that they could be baked into say, a batch of brownies without anyone noticing, and then some unsuspecting person chips a tooth on them. Swallowing them would likely lead to no harm in most cases (they would pass through the GI track in short order and with minimal hydrolytic degradation), and there would be no chance of them leaching anything into the flour (they are already approved for direct food contact in order to be used in the sifting process), but nonetheless, they don't belong there and so the recall is appropriate.

The irony here, is that while the FDA doesn't allow these contaminants into wheat flour, they do allow up to 75 insect parts and 1 rodent hair in a 50 gram sample. Bon appetit!

Wednesday, February 20, 2013

Rumor has it...

...that the 9th pitch drop in the infamous Pitch Drop Experiment is going to fall sometime soon. (Rumor source)

This rumor has all the same rank and foul-smelling truth as the endless false prophets who continually predict and re-predict 1) the end of the world, 2) a major stock market crash (worldwide or otherwise), and 3) the outcome of sporting events: if you say it long enough and often enough, the day will eventually come when by luck, your prediction is right. Not that the soothsayers were right, just that their "prediction" finally came true - very big difference.

Now it is possible with the Pitch Drop Experiment to distance oneself from these previous examples a good amount. For starters, we know that the pitch drop will fall at some point. Further, given the time intervals between previous drops falling, things are looking probable that 2013 will finally be the year in which the the drop will fall. What potentially makes this drop unique is that someone might actually observe it. (There is a webcam on the experiment so have a look-see. You might be lucky enough to see the big event.)

The 8th drop fell when the video recording equipment wasn't recording as it should have been. Fortunately, no one has actually concocted a conspiracy theory to suggest that a secret cabal of rheologists are running this "experiment" to fool the public for financial gain. But just look at the facts! Rheologists have a secret ancient password - "Panta Rei" - combined with an ancient chronometer:

They use secret symbols such as η* and Ψ2. They speak of "cortational models", "codeformational models", and take the name of the Lord in vain with their "Christoffel symbols". They have annual meetings in small towns that no self-respecting technical group would meet in (such as Minneapolis, Minnesota in 2002 and Lubbuck, Texas in 2005) so as to avoid the scrutiny of the public eye. If rheology is such an all-encompassing field, then how come no school in the world offers a degree in it? It's a cult I tell you! Black magic! Beware! The next drop that falls is the work of the devil, what with the black pitch being as dark as his soul. Watch if you must, but you will see nothing. The rheologists will once again strike and ensure that nothing is seen so that people continue to put faith into their lies of solids flowing like liquids.

Monday, February 18, 2013

Viscoelasticity in the Bathroom

This is an exciting post for me as it features my directorial debut in the video world. You decide: move to Hollywood, or don't quite the day job?

Before we get to the reel, here's some background on the film. As I've mentioned on many occasions, the bathroom is full of non-Newtonian materials. Bingham fluids - materials that don't flow until a large enough stress is applied - tend to dominate. Toothpaste is the most visible example. And then there's the classic Bristol Scale for describing the flow characteristics of human faeces. But new examples of viscoelasticity can show up in unexpected places as you shall see.

This post is about a new toilet seat lid that I recently installed in my home. The old one was loose and tightening the bolts was just not working out. Besides, it was a heavy wood one that let out quite a boom when it fell. After a trip to the local big box, my wife and I decided to try a seat that is viscously damped - it will fall slowly after just a small tap to start it on its way.

Changing a toilet seat may seem like a 5-minute job, but I assure you it is anything but. You have steel screws that are in a damp location (i.e, exceddingly rusted) and pretty much impossible to access without a very deep socket - assuming that the nuts are even of a normal shape. Mine were coated with plastic with some odd C4 symmetric pattern obviously designed to be turned by fingers. I'm sure they were easy to install way back when, but there was no way they were moving anymore.

If you look at Google results beyond the first 20 or so sites that tell you how easy it is to change a toilet seat (and in principle it is) you get to all the discussion sites filled with people having the same problem - the husband thinks it's a 5 - 10 minute job and it is anything but. The best approaches seem to be to hit the bolts from above. There is a YouTube clip out there where a guy takes a grinder to the bolt heads and is done in about 10 seconds, albeit he will be spending a couple of hours repainting the ways. The much milder approach is to use a hacksaw, or in most cases, just the blade since you are trying to cut parallel to the toilet. I took that approach and in 45 minutes, voila! I had this:A thoroughly destroyed hacksaw blade and two cut bolts. (Note the leather gloves - PPE is just as important at home as in the lab). Putting in the new seat was easy, although I was not happy to see that the seat had steel bolts. But most likely some other poor guy will have to deal with that in 20 years...

Anyway, the seat is great (more on that in a minute). But the rheologist in me had to play with it and quickly found out something else about the seat:
video
It's viscoelastic, not just viscous. That's not unexpected as all fluids - even water can show viscoelasticity. Something this viscous will usually show elasticity as well that can be detected with the naked eye. I'm already thinking about how to quantify some characteristics of the material sometime soon (my wife thinks I'm nuts...)

One last comment: I mentioned that the toilet seats work great. Too great. In fact, they can be counterproductive. I've ending up slamming the other seats in the house when I absentmindedly forget which toilet has which seat. So instead of there being less slamming, there is now more slamming. Be warned: change none of the seats in your house or all of them. There is no happy medium.

Thursday, February 14, 2013

Plastic Waste as Hazardous?

There is nothing like seeing this article,"Classify Plastic Waste as Hazardous", to get my blood boiling. And it's only 7:30 AM. And it's published in Nature. And there is a PR cavalcade to go with it so it has already been picked up by the LA Times and the BBC. Others will soon follow.

What a horrible little article. It's full of emotional pleas, overreaching statements and conclusions... I can't even begin to correct it all. The irony to me, is that it was published in Nature. I say irony, because at least when I used to have a personal subscription to that journal, more often than not it arrived in a plastic bag which was immediately torn open and put in the trash. So the authors have decided to publish in a journal that generates "hazardous waste". But let's overlook that, as sometimes even pacifists have to take up arms.

Before you even get to the text, there is this picture, designed to give you the impression that most or all of our lakes and oceans are like this. They are not.

They have to use such a picture as a true picture of trash in the ocean gyres is dreadfully boring. There's really nothing there much to look at unless you get out a magnifying glass. The Scripps Institute has taken this picture:

but that doesn't really get you all emotional, does it? As it has been described before, the "Great Garbage Patches" are not islands, but galaxies, mostly filled with empty space (or salt water in this case).

Let's look at the first sentence
"Last year, 280 million tonnes of plastic was produced globally. Less than half of it was consigned to landfill or recycled. Of the remaining 150 million tonnes, some may still be in use;"(emphasis added)
This simpleton math - (X tonnes produced - Y tonnes landfilled/recycled = Z tonnes pollution) is applicable if and only if all plastics are consumable. But they aren't. The authors hint that some MAY still be in use, but they really didn't look into it. So I think we can assume that they then wrote this article without the use of computers (or maybe they use a wood mouse and keyboard, and they have bare metal wiring for the electricity and ethernet connections), that they sit on wood chairs (without any urethane or acrylic coatings and most certainly without foam cushions) and there are no synthetic fibers in their clothing. Don't get me wrong, I'm not saying that the authors are trying to avoid plastics like some people do - it's just that they don't know any uses of durable plastics and I'm pointing them out.

Or how about this howler:
"We believe that manufacturers of plastic, along with the food and textile industries that rely heavily on it, should have to prove that their products and packaging are safe."
You mean they don't already? These authors seriously think this? All that time I've spent worrying about direct and indirect food contact testing, and now I find out that I never had to do any of it? Or that equivalent time I submitted samples for cytotoxicity and animal testing? You mean the FDA was only joking that they wanted the information that my coatings were safe? I sure have egg on my face.

I could go on and on, but you get the point. The article is a worthless pile of trash that should itself be considered as potential hazardous waste due to the pollution that it will introduce into certain minds. The article isn't even worth responding to with a direct letter to the editor of Nature.

Friday, February 08, 2013

A Rare Treat for a Chemist/Engineer

My recent trip to the underworld exposed me to a wide range of temperature swings. Above ground over the course of the week, the temperatures ranged between 57oF (14 oC) and 0oF (-16 oC) with -40 windchills (that being well known as the only temperature where oF = oC) and some freezing rain in between. And then the mines were a damp 55 oF. Combine all of this with half a dozen flights on Bombardier CRJ200's (which in most cases meant taking a hike on the tarmac) and I was not surprised at all that I came down with a nasty headcold this week. Writing this blog? No interest at all when my head was in the clouds. Somewhat ironic eh, given all the cloud computing we do these days...

While victory over the rhinovirus has yet to be fully achieved, interest in blogging has self-evidently been recovered.

Another exciting benefit of my new job is...well let me show you some pictures and you should be able to figure it out. This is my new lab bench:
Pretty clean, huh? Well, here's the next bench over:
Also clean enough to eat off of. Or how about this shot:
Or this one:
As you can see, it's a brand NEW lab. Nothing is in here. No balances, no beakers, no nothing. And so me and my labmates get to stock the entire lab. This is something I've never had to do before, and something that I doubt most chemists and engineers ever get to do. Start from scratch with not even a single piece of weighing paper. We are stocking it with the basics as fast as we can and hope to get down to some actual chemistry in another week or so.

One of my labmates has already ordered started ordering chemicals for his project. I haven't yet asked what he ordered that required this trifecta of hazard labels:
I can think of things that would match any 2 out of the three labels, but not all three. Maybe I won't ask.

I'll try and post pictures again of the lab in a few months. When I was still in school, we used to say it wasn't a party until a beer was spilled, so I'm thinking the chemistry equivalent would be that the lab isn't broken in until a) there's been a fire, b) a liter or more of solvent was spilled, or c) someone created something so rank and foul smelling that everyone left the lab for the afternoon.