It's the Rheo Thing

An Edible Drink Bottle - No Thanks, I've Lost My Appetite

2012-02-23T08:25:00.000-06:00

Plenty of people take issue with the existence of single-use water bottles and the related disposal issues, so the recent announcement of an "edible drink bottle" being developed by a Harvard professor may seem like a real winner. There is nothing to dispose of - you can just eat the bottle when you are done. No waste, no garbage, no nothing to end up in the environment.

But before we all go out and invest in this technology, we need to review everything that a drink bottle does:.

It needs to seal the water in and all other contaminants out.
It needs to be made from materials that will not leach unsafe levels of chemicals into the water, or react with the water.
It needs to not have any structural failure:
- during shipment from the bottles' manufacturer (who is often someone different than the company filling the bottle) to the filling plant
- while it is in the filling equipment
- while the bottle is put into
- or during shipment via (multiple) trucks or boats
- while on the shelf or rack, particularly when multiple layers of filled bottles are stacked on top of it
- during the "normal" lifespan that the consumer has it
- Keep in mind that during shipment and in the hands of the consumer, the bottle can see temperature extremes from below freezing temperatures to 140 oF or more, as well as UV light which can degrade polymers. If there is structural failure, the water will leak from the bottle, requiring that at the very least, that bottle be thrown away or recycled. Keep in mind that that bottle's contents are then also wasted. Depending on the extent and location of the leaker, the cardboard packaging may be weakened so that handling the other bottles or even the pallet with a forklift may be a problem, and therefore many more bottles may end up being trashed.
The bottle needs to cost as little as possible.

The water can only diffuse very slowly through the bottle's walls. Once too much water has evaporated, the bottle no longer holds the volume stated on the label, say 500 ml. Now it's mislabeled, and cannot be sold, so into the wastestream it goes.

I think this list is a pretty daunting challenge for the new material. Nothing was mentioned about the strength of the new material nor the diffusivity of water and other liquids through it, but considering that it is described as a "membrane", it probably leaks like a sieve. I've done enough product development to know better than to expect detailed costs estimates at this point, but this new material will be expensive if for no other reason than it will have to be treated as a food item and that means a whole boatload of regulations need to be followed in the production of it that a simple PET bottle is exempt from.But the real limitation will be this: if the bottle is to be edible, then it will have to be kept clean and sanitary, just like all food is, and the only way to do that is to have additional packaging around the bottle and that pretty much defeats the whole purpose of the bottle, doesn't it? Unless a PET bottle is filthy, people give little regard to where it's been or who/what has touched it, but if you are going to be eating that bottle, then everything contacting it will be a concern. A coworker handing you a bottle would be just like that coworker handing you a donut - not the box of donuts, but a donut directly with their hands. Anybody still hungry for these bottles?

To Develop Biofuels or Not?

2012-02-22T08:29:00.001-06:00

One aspect of photosynthesis that has always struck me as odd is the poor efficiency of that reaction: about 1%. This inefficiency is embarrassing enough, but when you consider that it is the result of 3.5 billion years of evolution, it becomes abominable. While research is being done to try and increase it, I think that the eons that nature has had to work on the problem pretty much guarantees us failure. For whatever reason, plants started out with an inherently poor reaction and have optimized it about as much as they can. Evolution can only build on what was there before. It is constantly working with legacy systems, and can never completely escape what was there before. What is really needed is a quantum leaps - the development on an entirely new photosynthetic mechanism, but that is far beyond our current capabilities and will be for the foreseeable future.

As a result, any efforts that we put into the development of biofuels will be limited by those same inefficiencies. Nobel Prize winner Hartmut Michel has a short editorial entitled "The Nonsense of Biofuels"(open access) which details the inefficiencies that I just described. He is not completely against the idea of only harvesting food from plants, but instead proposes that "[t]he best use of the biomass lies in its conversion into valuable building blocks
for chemical syntheses." This is the same idea that is indirectly echoed in another recent editorial entitled "Alternative feedstocks: a continuing trend in the polymer industry?" (open access). I say indirectly as this latter editorial advocates strongly that refineries for biofuels will be developed on a size and scale comparable to existing petroleum refineries, all the while recognizing that in the refineries, "[b]iomass...loses all of the chemical complexity that is inherent in bio-derived molecules."

I may have a biased perspective, but this does seem to be by-and-large the options that are being explored by industry. News of biobased chemical developments and investments in the corresponding plants seems to be dominating that of biobased fuels, so it seems that at least for now, we are moving in the right direction.

Recycling Wine Bottles

2012-02-21T09:14:00.000-06:00

Today's post is inspired by the comment left by an anonymous poster on a different website. The website mentioned that Amcor is now supplying both natural and synthetic corks for their PET wine bottle. The anonymous poster had a one-line comment:"At the end of the day, I would rather recycle the glass".

While this is a nice thought, the reality is that wine glass bottles are difficult to recycle. They are green and the largest user of green glass is the wine industry, with imported beers following after that. Unfortunately, the wine industry is located in very small regions of the country, so while you can place a wine bottle into a recycling bin, the recycler who then takes that bottle will have a difficult time working with it. Shipping it to California is not a viable option for most of the country, as is re-exporting the beer bottle glass.

On the other hand, the marketplace across the country for recycled PET has never been better, and since a case of wine shipped in PET bottles is lighter the glass alternative, less fuel is needed to transport it in the first place, making it a much more green option overall.

A Green Polyethylene - Is It Worth the Effort?

2012-02-20T06:45:00.000-06:00

Plastemart is reporting that "[a] method of converting plant matter into ethylene and propylene using a nanotechnology process that offers an alternative to oil-based production, has been developed by a team from Utrecht University and Dow Chemical Co, as per Reuters. This also means they will not be biodegradable [*], although they will be made from renewable resources."

This strikes me as odd - not that it can't be done - but that anyone would try to undertake this. Polyethylene (PE) is the largest volume plastic in the world. It has been in that number one position for as long as I can recall and I don't see anything displacing it in the near future and possibly forever. Similarly, polypropylene (PP) is the second largest volume polymer produced in the world and again similarly, nothing is going to displace it anytime soon.

Given these large volumes of plastic, it may seem like making more would be a good idea since the demand is already so high. The problem with making more of these plastics however, is that the existing margins for these materials are very thin. They are made in highly specialized, extremely large (200,000 metrics tons or more) and expensive factories ($200 million or more), all in an effort to squeeze out costs. If you wanted to get into the polymer business, PE and PP are not the way to do it. This is not a "make a little, sell a little" business that you gradually scale up. You go all in or you go home. If you want to start small and grow, start with more exotic polymers that you can make and sell in very small quantities - medical grade plastics such as used in coatings are a terrific example. As the demand for your product slowly grows, you can slowly increase capacity. Plus you can sell them for a lot and make large margins.

But as we've discussed here many times, Dow works exclusively on a big scale. They have no interest in low volume polymers - the bigger the better, and so the idea of having a green source for polyethylene and polypropylene are going to catch their eye. While I think that this is potentially interesting to source these polymers from plants and not petroleum byproducts, unless the economics of this option are significantly different than existing option, I can't see this technology getting off the ground. It works in the lab, fine. It will be cheap enough to build a small pilot line, and see how the scale-up goes, although even that will be fraught with problems. The pilot plant will make such small amount of materials that no one other than a small-time operator would be able to use these novels materials, and Dow will be far more interested in the opinion of large consumers (Berry Plastics, or Bemis or Trex) and not 'Bubba John's Blow Molding, Insurance & Appliance Repair Shop'.
It the classic chicken-and-the-egg scenario: Dow needs to make a large quantity of material to decide if they want to make a large quantity of material.

I am far more optimistic about other bio-sourced polymers. Sources for various diols, diacids, etc. are begining to emerge for making polyamides, polyesters, etc. and all of these will have the potential to make gradual introductions into the marketplace since the volumes needed to make the decisions about the viability of the new materials are not so high. The investment needed is lower and so you don't need a massive bank statement to get into the game.

[*] I would hope that anyone regularly reading this blog would know that just because something - plastic or otherwise - is made from renewable resources, it is not necessarily biodegradable.

Reusing Old CD's - but for Artists Only

2012-02-17T06:55:00.000-06:00

Like most people, I've plenty of old CD's that get pitched (microwaving them has lost all it's excitement), but if I were more skilled as an artist, something like this sculpture would be an incredible reuse for them:

This sculpture, and all the additional ones made by Sean Avery are tiny fragments of a CD. I have neither the patience, creativity or imagination to create something like this.

Hat tip to the ThisIsColossal webpage for the lead. A fascinating blog featuring visually impressive art from around the world. I highly recommend it.

Data Doesn't Lie

2012-02-16T07:20:00.001-06:00

An editorial in the current issue of Nature magazine ($) is so poorly written and twisted in its logic that I am shocked a respected journal such as Nature would publish it. The editorial is about methane emissions from fracking operations. Methane is widely recognized as a greenhouse gas - even by climate change deniers. But all of this is beside the point. I'm not discussing fracking, greenhouse gases or climate change today. Instead I'm focusing on two aspects that every scientist and engineer deals with daily: data, and making conclusions from data. Here's how not to do it:

"How clean is natural gas? Although it is often lumped in with coal and oil, many in the energy industry are at pains to point out that burning gas to generate electricity produces fewer greenhouse-gas emissions than does burning other fossil fuels. Certainly, countries claim reductions in carbon emissions when they switch from coal to gas, as Britain did on a large scale in the 1990s...Industry maintains that the problem has been exaggerated, and many scientists agree. Sorting fact from fiction has been difficult, however, because nobody had any independent data — until now.

As discussed on page 139, a study led by scientists from the US National Oceanic and Atmospheric Administration (NOAA), headquartered in Washington DC, and the University of Colorado in Boulder looked at methane and other emissions from a natural-gas field north of Denver, where fracking methods are used to open up sand formations. They estimated cumulative emissions from the field using not industry reports or conceptual models, but concentrations of pollutants in air samples. This is important because the atmosphere does not misrepresent data or make mistakes; nor does it bend to ideology or political will.

The data suggest that methane emissions from natural-gas operations could be substantially higher — and so be worse for global warming — than was thought. At works in the Denver-Julesburg Basin, methane emissions were roughly double the official estimate.

This will by no means settle the debate. The NOAA scientists had to make assumptions to convert atmospheric data to cumulative emissions from a vast energy complex. They readily acknowledge substantial uncertainty in their calculations, and estimate that between 2% and 8% of the methane produced from wells in the Denver-Julesburg Basin is lost to the atmosphere, with a best guess of 4%."

(emphasis added)

Wasn't that a perfect setup? "This is important because the atmosphere does not misrepresent data or make mistakes; nor does it bend to ideology or political will." So then how come "this will by no means settle the debate"? We have ideologically/politically neutral data? What's the problem?

This is a perfect example of the Achilles Heel of science: making a conclusion from data. It is such a fragile endeavor because it involves human beings and their thoughts and their biases. That is when assumptions are made and logic is applied. Worse yet, there is no guarantee that any conclusion reached is correct. This is why we have climate change deniers - not because of data, but because of the conclusions made from it.

How can Nature publish an editorial like this that is so removed from an understanding of how science works?

ISO 17025

2012-02-14T08:01:00.002-06:00

Aspen Research is now officially ISO 17025 certified. The certificates finally arrived in the mail yesterday. A lot of people here spent a large amount of time for those sheets of paper that are so precious - or are they? The certificates are 4 sheets of paper obtained with less than a years worth of work. Everybody reading this blog has spent (or is spending) 4 years just for a single piece of paper. [*]

I was not actively involved in the effort, but from the outside looking in, I would explain ISO 17025 vs. ISO 9001 this way. In ISO 9001, you wrote down what you did, you did it and then you write down what you did. The quality of what you did did not matter at all. You could make the same rotten stuff day after day and still be ISO 9001 certified - and there are plenty of companies that operate that way. With ISO 17025, you now have to show how well you do something. It still may be awful, but now it is known to your clients that it is awful.

Note to self: do not ever again work for a company that simultaneously pursues ISO 17025 certification and relocates to a new building.

[*] Some of us were so excited about that arrangement that we repeated that effort! And guess what? We are too. GLP registration is the next target.

Eating Plastic

2012-02-13T10:30:00.000-06:00

As you might imagine, I love plastics and other polymeric materials. They intrigue my mind and they have allowed me to make a living using that knowledge. At the same time, I realize that they have their limits. There are times that metals will solve a problem better, or maybe ceramics or sometimes, maybe nothing at all is the best solution - I'm thinking of the Vuvuzela as a good example of something that should not be made at all -regardless of the material used.

To be clear - there are times that plastics are the wrong choice. Such as in the case of this young women who eats plastic. Yes, eats plastic. And not just in small doses, but large quantities - 60,000 items - including

"I have eaten 12 remotes, over 5,000 beads, over 1,000 cocktail swords, 100 forks, about ten water bottles, two pacifiers, three CD cases, about 50 hangers, about 25 plastic lids on to-go cups..."

I hope that she gets some help, as eating all that plastics cannot be good for anyone. I'm not thinking about anything leaching from the plastic, but just the large bolus of indigestible items that could lead to blockages, punctures and all sorts of physical issues. As I said, plastics are often the wrong choicee and that is clearly the case here - proper food would be so much better.

Stokes Flow

2012-02-13T08:52:00.001-06:00

Anyone working with polymers is intimately aware of laminar flow. The viscosity of polymer is so high that achieving turbulent flow is pretty much impossible, at least for molten polymers. Solutions, and all the different ilks of dispersions are low enough in viscosity that turbulence can be reached, but for a typical molten polymer, turbulence isn't happening. Looking at the Reynolds number

Re = ρ v D / μ

(ρ is the density, v is the velocity, D is the diameter and μ is the viscosity) for different conditions can help show this. For circular pipes, turbulence can occur if Re gets above about 2100, so for a typical molten polymer with viscosity of say, 10⁷ Pa s viscosity and a density of 1 kg/m³ in a 1 m pipe, the velocity would need to be over 21 x 10⁶ m/s for turbulence to occur (that is 7% the speed of light)! Up the pipe diameter to 1000 m (the size of a nice river), and the velocity would still need to exceed a supersonic speed of 21,000 m/s.

Molten polymers actually under flow are at the opposite extreme: the Reynolds number is much less than one, a condition known as Stokes flow or creeping flow. When this happens, the inertial forces become negligible and the viscous forces dominate. The Navier-Stokes equations become very simple and in fact any time dependency in the equations disappear. This then means mathematically that the reverse flow is identical to the forward flow. While people can see this from the equations and are with it in an intellectual sense, seeing a reversible flow in real world situations is often quite shocking. Look at this video for a clear example:

That the initial conditions are not perfectly matched at the end of the video is due to a small amount of diffusion (Brownian motion) that is always present - just as if the initial colors would eventually spread out and mix over time in the absence of any flow field. Nonetheless, this would be a cool demo to put together. The colors are eye catching and while people may question the validity of it on video ("oh, they just ran the tape backwards"), this is one case where seeing would be believing.

A Sign Your Oven Might Not Be Working Properly

2012-02-10T08:29:00.000-06:00

When it's set to 75 ^oC and the paper label is charring...

...your oven might no be working properly.

Birds and Gels and Arsenic

2012-02-10T07:07:00.000-06:00

The last time I mentioned gels was over their use as the matrix for a cockroach repellent. I recently ran across another example of gels being used to repel undesired fauna - as a bird repellent. Apparently if you apply the gel to bird roosting areas, the birds dislike the sticky feeling on their feet and take flight. Speaking strictly from a rheological viewpoint, "tackiness" is largely independent of the thickness of an material, but only after reaching a certain critical thickness. Excessively thin layers will have lower levels of tack - something that the British city of Market Rasen recently discovered. They were testing a gel such is this on bridges, but applied it too thin. The material for 1 bridge was spread out over 3, so the gel was too thin and the tack was no where near where it should have been.

Another option for repelling birds, although in this case, it appears to be limited to bronze statues, is to have some arsenic incorporated in the alloyr. The mechanism by which this repels birds is unexplained at present. The only problem with this approach is that a new report ($) which looked at 6 elements of the "geologic copper family" (Cu, As, Se, Ag, Te, and Au) [*], concludes that the supply risk for arsenic is critical at a global level. As such, it making it available for use in semiconductors is in my mind more important than for keeping statues clean of bird droppings.

[*] Although these elements are scattered across the periodic table, they are a "geologic family" as they commonly occur together in copper ore deposits. Hopefully Th' Gaussling (a chemist with an intent interest in geology) can explain sometime how this occurs.

Biologists Messing with Polymer Nomenclature

2012-02-08T08:48:00.001-06:00

As has been well established, polymer nomenclature is often very confusing, for those interested, you can see my past entries 1, 2, 3, 4. Today's target: polyhydroxyalkanoates, aka PHA's, the bio-based biodegradable polymer that can't seem to catch the break it needs to hit the big time [*]. To be clear, I have not problem at all with the term polyhydroxyalkanoate - it's a perfectly acceptable description of the polymer:

These area ll polymers based on hydroxyalkanoates - alkanes of all sorts with both acid groups and hydroxy groups. The problem I have is that in the picture above, n = 0 should also be an option. If it is and R = ~~hydrogen~~ methyl, then you have another biodegradable polymer, polylactic acid aka PLA.

So why isn't PLA considered a PHA? Blame it on the biologists. Practically all background discussions on PHA's mentions how these polymers are derived from bacteria, usually as the little bugs are put under stress. PLA isn't made that way and so apparently that is enough of a distinction to cut it out from the group. It's a pretty strange way to slice it if you ask me.

Update: Corrected the value for R to correspond to PLA, not PGA - see the comments from Barney below.

[*] ADM and Metabolix recently announced that their joint venture to make and sell PHA is ending immediately. Not a good sign for the commercial success of this polymer.

Well, What is the Viscosity of Fudge?

2012-02-07T07:10:00.000-06:00

From Comic JK:

Polyurethanes - A Love/Hate Relationship

2012-02-06T08:39:00.000-06:00

I both love and hate "polyurethanes".

Polyurethanes (PU) are a condensation polymer [1], usually formed [2] by reacting a diiscocyante and a diol:

The reaction can then continue from either end, leading to a polymer. The problem with this polymer is that the urethane linkage is actually the least important aspect of the polymer - the R₁ and the R₂ are where the action is. It's R₁ and R₂ that determine whether you have a bowling ball, a car bumper, a kitchen sponge [3], a pressure-sensitive adhesive, a chair cushion [3], a floor coating or any of thousands of other products. Polyurethanes are without a doubt the most versatile class of polymers that we have, and that is why I love them.

But their name, "polyurehtane" causes significant confusion because it is a generic name that is generic only at the molecular level. While all condensation polymers, such as polyesters, polyureas, polyamides... have the same issue where their generic name focuses on the functional group that forms between them and not what is actually between the named functional group, this seems to be especially prevalent with polyurethanes, probably because they are so common. I've lost track of all the times clients and colleagues have told me that "they tried polyurethanes and they didn't work". If they had told me they had tried polyethylenes or polypropylene or polystyrenes or polycarbonates and they didn't work, I would be inclined to eliminate them from further consideration because the properties of a single grade of those polymers is not too terribly different from the properties of any other grade. But it is impossible to eliminate polyurethanes from consideration just because a few examples didn't work. As a result of this confusion, I usually have to explain what I explained in the paragraph above in order to get the clients/colleagues approval to still consider polyurethanes for their situation, and that is why I hate them.

One last thought: I've mentioned before that when someone tries to play "stump the polymer guy" by asking what a particular piece of plastic is made of, polyurethane is always an excellent answer. It may not be correct, but because of the versatility noted above, it is very likely not a stupid answer. And sometimes, appearing to be "not stupid" is just enough.

[1] Depending on your definition of "condensation", you could argue that PU's aren't a condensation polymer since there is no by-product formed.
[2] I say "usually", as there are plenty of isocyanate-free urethanes, but most of them have not made too much of an inroad into the marketplace. I suspect price to be a huge factor.
[3] This is actually a foamed polyurethane which typically is prepared by adding a small amount of water to the mix. I won't go into the details here.

Bunte Salts

2012-01-31T09:28:00.000-06:00

I was reading a patent yesterday and ran into the term "Bunte salt". I wasn't familar with the term, and from the context, it wasn't apparent what the term meant. The IUPAC Gold Book quickly clarified what a Bunte salt is, and also why I shouldn't have felt bad for my ignorance - they have declared the term is obsolete and its use, as of 1997, is discouraged. [1]

That message however, is not getting out, at least to industrial practitioners [2]. The first US patent to use the term was issued in 1960 and 171 additional patents using the term have been issued in the 51 years since, an average of 3.4 patents per year. But over half of those patents - 96 - have been issued in the last 10 years. I would love to do a literature search to break down it's use over time, but don't have any great tools available, so the patent results will have to do, and it is quite apparent that industrial chemists are thumbing their nose at IUPAC nomenclature. (But what else is new?)

[1] What a wishy-washy position to take! It is obsolete, but its use is discouraged. Dictionaries and grammar guides have to make a choice. They can either be descriptive (describing how people use a language without making judgments about it's "correctness") or they can be prescriptive (describing the correct way that a language should be used). Here, IUPAC is doing both.

[2] I'm using the term industrial practitioners as the vast majority of patents are written by them. I do acknowledge the existence (the ever growing existence at that) of university patents, but they still are an extremely small percentage of what is applied for and issued.

3-D Printing, Medical Organs and Piracy

2012-01-30T10:02:00.000-06:00

3D Printing has been becoming more and more popular this past year. Plastics Today has declared that the printing of medical organs could be a real breakthrough/growth opportunity for plastics in the near future, but the (semi-)cynical side of me notes that the capturing all that potential will be difficult once the pirates show up. Yes, that scallywag site for sourcing digital media, The Pirate Bay, now has "Physibles", files for preparing physical objects with 3-D printers. This means that it is now possible to duplicate 3-D objects across the planet, the legality of which may be entirely doubtful. There aren't many files at present, but this somewhat ironically a file for a copy of the Pirate Bay's ship:

But let's think about what happens when you combine these two stories: How long before someone can make illegal copies of an internal organ? And not just any organ that isn't overly important, but how about say, vocal cords? You want to sing like Adele? Or José Carreras? (And since people are already making 3-D printed versions of a Stradivarius violin, imagine the violin/voice duet that one person could perform!)

How long before we get into heart/lung transplants? Want the VO₂ max of Lance Armstrong? And then the ultimate transplant - the brain of Einstein. His brain is preserved at Princeton - how long before someone steals a segment and uploads the relevant information to Pirates's Bay? People will never be able to say about you again "He's no Einstein!".

Clearly all this at present is more fantasy than reality, but if the history of the internet and digital technology has shown us anything, it is that keeping information locked up for more than 10 years, let alone an eternity, is a futile effort. Once your organs are digitized, everybody will have access to them.

Open Access, Curation and Seredipity

2012-01-27T09:37:00.001-06:00

The issue of open access has raised itself up again this last week in the chemistry blogosphere. Rich Apodaca, author of the Depth-First blog, caused a stir when he came out in support of the Research Works Act, legislation that would at present prevent the NIH from requiring that research publications support by NIH grants cannot be placed in PubMed Central where they are freely accessible by anyone. (The bill of course, is written more broadly than that, but that would be the most obvious and immediate impact.)

But all this is prologue.

Rich made one argument that I strongly disagree with - that for a journal, the imprimatur provided by a journal is still valuable and needed.
"Any scientist who has been an active participant in scientific publication as an author, reviewer, and consumer recognizes that the only remaining value added by scientific publishers today is imprimatur. Imprimatur is the implied endorsement received by authors who publish in certain scientific journals, particularly in those that earned a high level of prestige during the pre-digital period of publication scarcity."
I disagree. The value of a "prestigious" journal is not the prestige, it is something far more valuable that we all are implicitly aware of, something that journal editors provide, something that gives the journal it's prestige and that is curation - deciding what is and isn't important. It is this step that provides the ultimate value of a journal. Without appropriate curation (lots more on that in a minute), the journal becomes a meaningless pile of data. Being peer-reviewed, it is accurate (more-or-less) but without guideposts.

As I said, we are all aware of this already, but just not explicitly. When that prestigious journal brag about how few papers they accept, what the journal really bragging about how much they curate. They are able to make great decisions about what their readers want to see and what they don't want to see. Effective curation over time leads to imprimatur. Without effective curation, your journal has papers which may or may not be of great value, but a landmark article in the Upper Midwest Journal of Photochemical Interactions in Northern Blots will never give that journal any prestige.

To me, if I was a journal that wanted to convince people that they should pay for it in this age when "information just want to be free" is the mantra, I would sell curation hard, very hard. All the other services that journals used to supply are now easily duplicated by all the disruptive technology available. Bur curation, and the ability to perform it well, is something valuable that still remains. It is what distinguishes Angewandte Chemie from Tetrahedron Letters. It needs to be recognized and it is worth paying for.
Let me go back to the subject of curation in a broader context.

As long as there has been mass media, there has been curation. It has never been possible for a mass media source to publish/broadcast everything so choices were made as to what was and wasn't going to be put out for consumption. In the past, those choices were made by a small group of people. If you were unhappy about their choices, there was little you could do. With the internet, curation initially appeared to have died, as everyone could have access to everything. But even with all those choices, mainstream media sites still remain popular destinations because of their ability to effectively curate. As with very selective journals, when the New York Times makes the statement "All the News That's Fit to Print", they are referring to their curation abilities.

Curation will never disappear. I would suggest that there is a basic human need for it. If it is lacking, someone, somewhere will create it. It is also fairly obvious that it is needed now more than ever. The information that we have access (or potential) access to is greater than ever before, and becoming greater with each passing day. Some of the most visited websites - the Drudge Report is a terrific example - are nothing more than curation sites. Matt Drudge decides what to link to on his page and doesn't provide any explicit editorial comment other than the headline for the link, and yet his sites has millions of hits per day because he has a great sense of what people want to see. If he ever loses this sense, his page will drop in it's importance.

Curation has also started appearing in our search engines. This is certainly a new concept, one that has never before occurred in our history. Early search engines on the Internet gave a haystack of results with little effort to prioritize the results. The searcher was expected to do find the good from the bad. Google became a dominant player because it was able to prioritize webpages - decide what was more important. But they didn't stop there. It is now becoming more well known that Google will further alter search results based on information it has gathered about your from past searches. A recent example of this was seen in the engineering sub-reddit, where an engineer posted a screenshot of what the Google image search showed for "pump" - quite a few high heeled shoes, more than he would have liked.

Here's what an identical search for me produced.
A lot less shoes. As you can see, all the technical searches that I perform at work are then used by Google to slant the search results towards what I am most likely interested in. (I imagine that the reddit engineer was searching on a computer often used by his girlfried.)

I've noticed over the years that my Google searches have become increasingly productive. I used to think that it was because I was becoming a better searcher - choosing better search terms - but now I am not so sure that Google isn't doing a better job of providing the results. Regardless, Google's efforts to provide relevant search results is a rather desirable outcome - in most situations. I'm looking for specific information and I don't have a lot of time, so not having to scroll down the page at all is invaluable
And yet, there are times where curation is that last thing that we need. With the more poignant search results, it becomes increasingly difficult to stumble upon something new, something that you find interesting, something that you didn't know you were looking for. I'm old enough to remember when libraries had card catalogs - collections of cards in drawers that could be searched to find a book in the library. Searches were typically possible by the title of the book, the author and by subject. The unintended beauty of the catalog was that you could be assured that the first card you looked was not the card you wanted, and so you then started flipping through more cards until you found the one you wanted. And sometimes in this search, you would find something that wanted without knowing that you wanted it - serendipity! Further, once you found the call number for the book, you had to wander the stacks to find it, which could lead to further unexpected results, although that was not as likely as books were generally arranged by subject. (Ethan Zuckerman notes that Harvard is considering enforcing serendipity by reorganizing all the books by size!)

Now when we find books via computer search (either from libraries or Amazon), serendipitous outcomes are pretty much impossible. Even if you misspell a word, the search algorithms will overcome that and give you the "intended" result. Can you have serendipitous search results with Google? A decade ago when their algorithms weren't so refined, you could have. Now you can't. There is no "random search" option, no "show me something new" option, no "tickle my brain" option. And this is not to pick on just Google. Twitter will only show you what you have indicated that you want to see. Same with Facebook and endless other sites.

Serendipitous results can be found, but ironically, you have to work at it. Reddit/Digg/StumbleUpon and similar sites are places where people send links that they think are interesting. Their main pages provide the top results, so you will certainly see something new, although it will be what is most popular, a description that makes me wonder about humanity's fate at times.

Wikipedia is another place where it is relatively easy to get off the beaten path if you start following the links in an article or the "see also" links. And serendipity is why I enjoy the journals Nature and Science - they have research from all fields of science, not just the polymers and rheology that I specialize in. (I do note the irony that these journals are also very well curated. More journals of such broad coverage in the future would be another route to enforce serendipity!)

Curation and serendipity are opposite sides of the coin, but paradoxically, we need both. Curation seems to have the upper hand at present and that trend will continue for the foreseeable futher, while serendipity is being forced to the side, something that we have to struggle to keep alive.

And finally getting back to the issues of open access that this post started with, curation is still the last valuable service performed by journal publishers that cannot be replace by technology - at present. Can algorithms be developed that can perform the curation for us? I wouldn't ever bet against that. In fact, I would expect to see it in my lifetime. But the real question is this: do we want that? (Sadly, I think the question might be better stated as: How can we prevent that?)

As a last comment, the blog entry by Ethan Zuckerman, Desperately Seeking Serendipity is a wonderful read about serendipity in cities and other geophysical structures. It is a long article, but well worth the time. Mind-opening.

Viewing History through an Oil Refinery

2012-01-26T10:55:00.003-06:00

It's probably a result of my education (but not my career path) in chemical engineering, but I love look looking at refineries and pictures of them. Hydrocarbon Processing" is my favorite trade journal to flip through because of the cover picture as well other photos inside. I am always amazed by the tangled pipeline, the endless columns, pumps,...such as I see at the Pine Bend Refinery located just south of town here:

When oil/petroleum refining was first developed, such complicated plants were not needed, and that was probably a great thing as no one would have been able to design such a complex monstrosity a hundred years ago. A distillation column, maybe a tank or two and some simple plumbing would have been enough. The outputs would have been just a crude - a cut for lamp oil, and maybe some gasoline, and then the tar at the bottom was probably just a waste pile until someone figured out that it would be good for roadway surface. But as the demands for these products became more rigorous, the demands on the refinery increased, and so did the equipment. More fractions could be taken, and the fractions needed higher purity. Things like sulfur became a concern, and so removing it required additional processes. Recycle lines were added along the way to increase productivity. The chemical industry was growing and was able to take undesired waste, but only if the waste was of a more consistent output. This continued until we have the huge plants that we see today. Yet at the heart of the plant is still the distillation column. The columns, plants and plant sites are all new, but the thought processes that justified the additional equipment, the history of the refining industry is still there for all to see.

Confusion over "Polymer"

2012-01-25T07:36:00.000-06:00

When I wrote yesterday's post about the confusion in the general public on the term "vinyl", I thought it would be a stand-alone topic. But late yesterday I found an article that is forcing a followup. Only in this case, the confusion is not in the general public, but with theoretical physicists. And in this case, the word is "polymer". As in the title of this paper: "Polymer Quantization on the Half-Line". Here's the abstract:

"We investigate polymer quantization on the half-line, constructing a one-parameter family of polymer Hamiltonians that are analogous to the Robin family of continuum boundary conditions for the half-line Schrodinger Hamiltonian. Applications include the free particle, the attractive Coulomb potential, the scale invariant potential and a black hole described in terms of Einstein-Rosen wormhole throat dynamics. The spectrum is analyzed by a combination of analytic and numerical techniques. In the continuum limit, the full Robin family of boundary conditions can be recovered via a suitable fine-tuning but the Dirichlet-type boundary condition emerges as generic."

"...a blackhole described in terms of Einstein-Rosen wormhold throat dynamics"? Not exactly the polymer science that I am aware of, although I bet you get an incredible extensional flowfield going into a blackhole. If any one can explain this use of "polymer" to me, I'd love to hear it, but I'm not holding my breath. I've sent the first author an email and will see if I get a response.

Confusion over "Vinyl"

2012-01-24T10:11:00.000-06:00

I recently had to clarify for someone what the term "vinyl" means. The confusion arises from the fact that it is commonly used by the general public, not just chemists. For the former group of people, the term refers to the polymer "polyvinyl chloride" (PVC), such as the vinyl drainpipes sold in hardware stores. For a chemist however, vinyl refers to a mono-substituted ethylene molecule, such as the vinyl chloride monomer (VCM) used to make PVC. [1]

You can see that the general public uses vinyl as a noun, while chemists use it as an adjective, a word to modify a noun, such a vinyl group, vinyl chloride, vinyl acetate, etc. But even for chemists, the use of "vinyl" for a mono-substituted ethylene group isn't consistent. α-olefins are a good counter example. 1-hexene is not ever referred to a vinyl butane [2]. I am unaware of any particular rules defining when to use and not use "vinyl", other than to state that it is not acceptable at all for IUPAC - they prefer the term "ethenyl".

The confusion that I referred to earlier came about with the term polyvinyl acetate (PVAc) and the perception that this polymer (the PVAc) would have some PVC in it, and in particular, chlorine. The "vinyl" in this case however, does not refer to VCM or PVC, but rather what chemists mean by the term vinyl - a mono-substituted ethylene group. In the case of PVAc, the substituent is an acetate group. There is no vinyl in polyvinyl acetate, there is no vinyl chloride in polyvinyl acetate, and there is no polyvinyl chloride in polyvinyl acetate.

A related monomer and polymer that I won't go into today are vinyl alcohol and polyvinyl alcohol. I've discussed them in the past, so you can look at this post if you want to find out about the monomer "vinyl alcohol" that doesn't exist, even though polyvinyl alcohol does.

[1] Di-substituted ethylene groups (assuming both substitution are identical substituents and are on the same end of the double bound) are called vinylidene groups, such as vinylidene fluoride, F₂C=CH-, entities that are far less common than vinyl groups.

[2] Or would "vinyl butyl" be more correct for this incorrect construction?

Free Access to Polymer Research

2012-01-20T09:21:00.000-06:00

I updated the page on "Free Access to Research in the Polymer Literature" (see the tab above). There are more sample issues, as well as a number of individual articles covering topics from branched polyethylenes to thiol-ene [*] prepared protein bioconjugates to solar photovoltaics. Something for everyone.

[*] Long time readers know that if there is thiol-ene article, I'm on top of it.

A Bad Day in the Operating Room

2012-01-19T09:05:00.000-06:00

This is an x-ray of a patient's lung. The small white stripes in the upper left are PMMA. How did PMMA get in his lungs you ask? Well, he was having back surgery. Still not obvious to you? O.k., here's the full story as explained by the article in the New England Journal of Medicine. The patient was having back surgery to fix spinal cord compression. The surgery involved injection methyl methacrylate (not polymerized) into the back, whereupon it does polymerize (with a nice little exotherm I might add). The procedure is called vertebroplasty. [*]

As is known to occasionally happen, some the the acrylate got into the bloodstream around the bone and was transported to the lungs. The plastic did interfere with the patient's breathing for a while (low O₂ levels in the blood) as well as some mild increases in blood pressure. The doctors that submitted this image to the journal noted that in extreme cases, serious illness and even death can occur as a result of these types of complications.

The Wikipedia article on the procedure has quite a discussion about the effectiveness of the procedure, or more properly, the lack of effectiveness. Combine this with the risks illustrated here and I can certainly state that I would not want this done to me. I like plastics a lot, but only outside of my body, and most certainly not in my lungs.

[*] It's great to have Wikipedia back, isn't it. I missed them yesterday, but their blackout did get me to sign a petition against the SOPA/PIPA bills and contact me representatives in Congress about the issue.

Criticisms of "Atom Economy"

2012-01-18T09:32:00.002-06:00

When I wrote about "atom economy" yesterday, I tried looking around for some serious criticism of the approach and didn't find much, so here are my thoughts.

Atom economy is defined by Barry Trost of Standford (subscription/pay-per-view) as the molecular weight of the product divided by the sum of the molecular weights of the reactants.

Chemists have in the past relied on yield percentages to measure the efficiency of a reaction. If there is 10 millimoles of A at the start of the reaction and it is transformed into 9 millimoles of B at the end, the efficiency is 90%. These yields are important, as many reactions are part of a multi-step synthesis. If a 5-step reaction has 90% yields for each step, the overall yield is 0.9⁵ = 59%.

With that 90% yield however, there may be a mountain of chemicals, solvents and catalysts left in the wake of the reaction and that shouldn't be ignored. In one of my earliest jobs working with coating solvent-dispersed adhesives, we were all very much aware that for every 3 gallons of adhesive brought into the plant, 2 gallons of solvent (plus a lot of heat) went out the roof of the building to the thermal oxidizer, so certainly a "big picture" approach to chemical reactions is needed. It;s just that I think atom economy is a lousy option.

The impact of atom economy is greatest for large volume, industrial situations, and not small academic labs. However, much of the research published on atom economy concerns academic research rather than industrial preparations. While in some cases, the difference between the two is mostly a matter of scale, in other cases, industrial processes are whole different than research lab processes. Worrying about the atom economy of a non-industrial reaction is a waste of time.
By focusing solely on the nature of the reaction and not the actual chemicals involved, atom economy overlooks process concerns such as ease of separation of the product, the hazardousness of the reaction and the byproducts, etc.
- It inherently favor reactions without any byproducts (additions and rearrangements) and disfavors all others (substitutions, condensations and eliminations).
- It also favors the upper rows of the periodic table. Lower rows, while often being more reactive, have greater atomic masses and are therefore disfavored by the calculation. Yet many preparations of fluorinated compounds are far more dangerous and hazardous than the chlorinated equivalents. Is this not a concern?
It is often unclear exactly what "the reaction" is. Taking the example again of (poly-)amide formation between an acyl ~~chloride~~ fluoride (lower MW in the reactant = GOOD!) and an amine. I'm not aware of any naturally-occurring acyl fluorides, so that material was prepared at some earlier point. Shouldn't that reaction be included in the overall calculation as well? And what if the amine also required preparatory reaction(s), shouldn't that be included in the atom efficiency calculation as well? How far back should this all be pushed? Is cradle-to-grave the proper approach? Or can we game this to a better starting point? (I find it rather ironic that the modern organic chemical industry itself is a "byproduct" of the petroleum industry. If the refiners had practiced better atom economy, modern organic chemistry would be much in arrears from where it is today.)

Just like yield percentages, atom economy looks at only one aspect of a reaction under the guise of being "green". A truly green approach however, requires some thought and critical analysis, not just a number that can be reported on a scorecard.

Amide Formation - A Case where Polymer Chemists Have it Easy

2012-01-17T09:21:00.001-06:00

At the end of last year, Nature had a review article (open access) on amide bond formation. As polymer people, we all know and love amide formation as the basis for polyamides, also known as nylons. Given the apparent ease with which many polyamide bonds can be made (watch the nylon rope trick video), I've never thought about amide formation as being a particularly challenging aspect of organic chemistry. I was wrong. Consider this quote from the article's introduction:

"The current methods for amide formation are remarkably general but at the same time widely regarded as expensive and inelegant. Not surprisingly, in 2007 the American Chemical Society Green Chemistry Institute (comprising members from major pharmaceutical industries worldwide) voted ‘amide formation avoiding poor atom economy [1] reagents’ as the top challenge for organic chemistry. Furthermore, even the best stoichiometric reagents often fail for the synthesis of sterically hindered amides [2]. The issues of waste and expense associated with amide formation are compounded when applied to peptide synthesis, and are responsible for the great cost of commercial therapeutic peptides. The chemical synthesis of proteins is largely prohibited by limitations inherent to traditional amide formation..."

(Footnotes are added by me and are located at the bottom of this article.)

In the nylon rope trick, the diacid is modified to form a diacyl chloride which then reacts with the diamine, in the process forming HCl. Fortunately, most commercial nylons are made from the straight diacid, or more correctly, the nylon copolymers such as nylon 6,6 are made this way. The diacid and the diamine form a isolatable, non-reactive salt which is then reacted at high temperature and pressure to induce polymerization. The nylon homopolymers, such as nylon 6, are made through a ring-opening polymerization of cyclic lactams. Most other organic compounds cannot tolerate the conditions or have an appropriate lactam, and so the search is ongoing for more and better techniques to create amides. Maybe some of these results will spill over into the polymer area, but I have my doubts. Just looking at some of the options

makes me thankful that we don't need to explore them.

[1] "Poor atom economy" refers to the molecular weight of the product divided by the molecular weight of all the reactants. It is a trendy way to quantify the efficiency of a reaction. I'll have quite a bit more to say about it tomorrow.

[2] All easy reactions fail for sterically hindered products. While polymaleic acid has been made, 2-olefins in general are still considered to be very difficult to polymerize.

Flying Cupcake Update

2012-01-16T14:11:00.000-06:00

Time magazine is reporting that a bakery in Rhode Island has risen to the challenge of TSA-stricken cupcakes and now sells cupcakes ensembles that include a cupcake with 3 ounces of frosting, a first class boarding pass, and a picture of Richard Nixon saying "I am not a gel!"

Ah! American Ingenuity at it's finest!

Previous discussion on this subject.