Science Policy and Communication

One of my favourite topics to get up on my soapbox about is science policy and that not enough of the policy makers have a true understanding of science. Now part of my usual rant with has to do with the fact that I am not blaming the policy makers for this, but rather chiding the apathy of the scientific community for not being more active in the policy making role. And that isn't entirely the fault of the scientific community either. Have you ever seen "question period" in the House of Commons? I would rather slide down a banister of razor blades and land in a pool of alcohol than participate in that. 

For me, I just want people to understand small things like what you read on the internet isn't necessarily factual or that medical doctors aren't experts in science and scientific studies are still done by humans and can have mistakes.

Things that can help people learn to read science without spending 11 years in university (yes, I spent 11 years in university study science and chemistry) are nicely summed up in this Nature article. We are at a point where information is so easily accessible. Now it is time to learn how to sort and process that information in a meaningful way. 

I personally love talking about science and all things science so that I can learn and I can teach. It is one of my favourite things to get other people as passionate for science as I am. And if I can teach you something then I feel my job here is done. Hence why I have this blog. I may not be able to write often, but I do love when I get the chance to write about something I love as much as science. 

Biodiesels

I am currently writing my dissertation for my Ph.D. entitled "The Use of Canola Oil as a Carbon Feedstock in the Synthesis of Value-Added Materials". One of the things that happens when writing a dissertation is that you do a lot of reading about interesting points tangential to your actual project. Since I am working with canola oil, I devoted a special section of my introduction to biodiesels, since 80% of the biodiesels used in the EU are made of canola oil. (They call it rapeseed, but it is canola oil.) I thought I would share some of the chemistry of biodiesels.

First, let's start with a little history. Did you know that diesel engines were originally designed to run on a renewable fuel source? In 1900, Rudolph Diesel presented his engine, which was powered by peanut oil, believing that biomass fuel was the future of the engine. However, come the 1920s, engines were altered to use the lower viscosity petrodiesel which was much cheaper to produce. This remains one of the huge challenges in sustainable development: economics. How much are you willing to pay for fuel because while the $1.30/L (Canadian pumps in Alberta) is pretty steep, it is still cheaper than biobased fuels because of the mass production infastructure. But I digress; this is a chemistry blog. 

Peanut oil is not technically a biodiesel. Biodiesels are transesterified vegetable oils resulting in fatty acid esters, most commonly the methyl ester. The vegetable oil is reacted with an excess of methanol in the presence of an acid or base catalyst (industrially it is usually the base sodium methoxide) to produce 1 equivalent of glycerol and 3 equivalents of fatty acid methyl esters. These are referred to as FAMEs. What is awesome about biodiesels is that they can be used directly in compression engines without modification to the engine and they can also be blended with petrodiesels because they are completely soluble. Because they come from plants, the carbon dioxide and water produced by the burning of the fuel are taken back up by the plants resulting in overall reduction in emissions. There is also a reduction in carbon monoxide, sulphates, particulate, and total hydrocarbon emissions. Which is all pretty great. 

But of course there are some major drawbacks. First, cost. As I have alluded, price plays a big role in industrialisation and biodiesels are currently a lot more expensive to produce compared to petrodiesel. Second, poor cold performance. This is actually a concern with diesels in general. But these longer chain fuels begin to solidify at higher temperatures. Huge problem in a place like Edmonton, Alberta where in the winter it is common to get temperatures well below -10 C. This is also why diesel engine vehicles require a block heater. Fuels need to remain liquid and low in viscosity to actually perform well. Third, and I think this is really important, is that the greenhouse gas (GHG) emission savings is much lower than expected, failing the sustainability requirements. The EU's Renewable Energy Directive (RED) demands a 35% reduction in GHG emissions compared with petrodiesels for biodiesels. They have estimated that canola-based biodiesels result in a "typical" 45% reduction while commonly using the default number of 38% in GHG savings. 

However, a recent study by Gernot Pehnelt and Christoph Vietze refutes these claims and points to GHG savings of, at best, 29.7%.  The authors claim there was a lack of transparency in the calculations performed by the European Commission. Running a life cycle analysis using the same basic methodology and background data as RED, and only utilising publicly available and published data in their calculations, the authors were unable to replicate the numbers reported by RED. Further, these calculations did not take into account for any of the other environmental or social impacts associated with using available agriculture land for fuel, which they argue would further decrease the sustainability of canola oil biodiesel. 

Another huge concern with biodiesels is that glycerol is produced as a by-product. The global production of glycerol has grown exponentially, well passed the global demand for this chemical. 

As we move toward a more sustainable future, it is important to recognise that the after over one hundred years of industrialisation based on petroleum fossil fuels, our journey has no quick solutions. It will be a long and complex movement, but with every step, even the smallest, we are that much closer to a sustainable future. This must be a global movement.

References:

Brown, B. A. Ph.D. Dissertation, University of Alberta, Not Yet Published.

 

Bart, J. C. J.; Palmeri, N.; Cavallaro, S. Biodiesel science and technology; Woodhead Publishing Ltd.: Boca Raton, FL, 2010.

Huber, G. W.; Iborra, S.; Corma, A. Chemical reviews 2006, 106, 4044–98.

Cheng, J. Biomass to Renewable Energy Processes; Taylor and Francis Group: Boca Raton, FL, 2010.

Ragauskas, A. J.; Williams, C. K.; Davison, B. H.; Britovsek, G.; Cairney, J.; Eckert, C. A.; Frederick, W. J.; Hallett, J. P.; Leak, D. J.; Liotta, C. L.; Mielenz, J. R.; Murphy, R.; Templer, R.; Tschaplinski, T. Science (New York, N.Y.) 2006, 311, 484–9.

Spellman, F.; Bieber, R. The Science of Renewable Energy; CRC Press, Taylor and Francis Group: Boca Raton, FL, 2011.

The Economic Impact of Canadian Grown Canola and its End Products on the Canadian Economy; 2011.

Knothe, G. Energy & Environmental Science 2009, 2, 759.

Gilbert, N. Nature 2012.

 

Pehnelt, G.; Vietze, C. Jena Economic Research Papers 2012, 39, 1–35.

 

 

A Yarn of Chemistry: All Ewe Knit to Know-Part 2

In part 1, I dealt with the chemistry of animal fibers: wool and silk. But animals are not the only source of fibers that we use for making yarns. Another source is from plants; these are termed "cellulosic fibers," as they are all primarily comprised of cellulose. I plan on covering cotton, linen, and hemp in this section. (The photo on the left is me in a yarn shop in Heidelberg, Germany.)

To begin, let's talk about the structure of cellulose. It is a polysaccharide. This means that it is a polymer (made of many units) and the repeating units are "saccharides" also called sugars, or carbohydrates. In cellulose there is only one sugar that is repeated to make it a polysaccharide. That sugar is glucose. Now this might surprise some people because we use glucose all the time: it is in starches, and refined table sugar, and the bowl of candy on my desk, all of which we eat and digest. But we cannot digest cellulose. And yet the part of the potato we can digest is made of the same stuff that the part of the potato that  we peel off because we can't digest. This has to do with how the glucose units are strung together. 

The picture on the right shows two molecules of glucose put together: the bond between glucose molecules is called the glycosidic bond and is highlighted in red. On the top is an "alpha" bond-this is how glucose that we can digest is arranged, so like starch. On the bottom is a "beta" bond-this is how cellulose is put together. Most animals do not possess an enzyme that allows them to break beta bonds and therefore they cannot digest cellulose. By having beta bonds in place of alpha bonds, the chain of glucose molecules becomes more linear and more rigid. This is why cellulose is used in plant cell walls: the rigidity gives the plant strength. 

Probably the most important cellulosic fiber is cotton. This particular fiber, unknown in Europe until the Middle Ages, is most associated historically with the growth of slavery and the industrial revolution. The fruit of the cotton plant produces bolls, in which the seeds are wrapped up in a mass of cotton fibers. The cotton plant requires long, hot summers, well drained soil, moisture, and no frost: this is why Canada has never been known for its quality cotton. There are many countries around the world that manufacture cotton, but the conditions that it is grown in can impact the properties of the fiber. The cellulose chains in cotton long and linear, due to the beta bond, discussed vide supra; this allows many chains to pack closely together and interact with each other through the formation of hydrogen bonds, making it highly crystalline.These cellulose fibrils are then arranged in essentially three layers that are spiraled together, resulting in the high strength that cotton is known for. This is important to know when working with cotton yarn because they are less stretchy than wool, and will show any mistakes or irregularities in your work. This can be quite frustrating for new crocheters or knitters. The other thing I have found when working with cotton is that the individual plies of the cotton yarn don't stick together as well as they do in wools, making really easy to put your hook through the strand. There are different standards of cottons. The longer the length of the fibers, the softer and nicer (and consequently more expensive) the cotton is. Egyptian cotton fibers are between 25-65mm, this is what makes them so lovely. American cotton is between 10-25mm. Another interesting property is that the fibers are actually stronger when wet.

Cotton is easy to wash, breathable, absorbent, and less of an allergen than wool. It also dyes very well, meaning that it can be found in all sorts of great colours. One of the most common projects for cottons is dish clothes and towels, like the set I made on the left. Because you are going to be pretty hard on dish cloths, you don't want to use high quality cotton, go with shorter, rougher cotton. Now when making something for a baby, cotton is not a bad choice. I most recently used cotton in a baby blanket. Anything you are making for a baby, you want to make sure that it washes easily because it WILL get dirty and they aren't going to be gentle with it. Here is a great project for a nicer cotton. The longer, softer fibers make a nice blanket. 

The next type of cellulose fibers are called "bast fibers". These are ones that are derived from the stem of the plant. Unlike cotton, these fibers are part of the structural make up of the plant, and the job of holding it up requires a lot of reinforcements, meaning that these cellulose fibers are mixed with a bunch of other things like: pectins, gums, waxes, lignins, and hemicelluloses. 

Linen has to be one of the oldest, if not the oldest, cloth fibers. Seriously, hop in your time machine and head to Egypt in 8000 B.C. and you will find linens.  This prized cloth is made of fibers isolated from the flax plant. Flax fibers are found at the surface of the stem and run the whole length. Since the stem is about a metre in length, you can see how flax fibers are longer than cotton fibers, ranging from 6-65mm (average length is 20mm). Flax fibers are also stronger than cotton fibers; actually this is one of the strongest naturally occurring fibers. Like cotton, linen is light-weight and absorbs water readily. It is easily laundered and takes dye well. It is a good conductor of heat, which is why it is so nice to wear in hot climates. As a dense fiber, it drapes well, but it also wrinkles super easy. Look at it the wrong way and it will wrinkle. Its stiffness can make it a challenge to work with, especially if you are just learning, but the history makes it an interesting choice too. 

Hemp is another bast fiber that is used in textiles. But for those of you who would like to use hemp as a reason to legalise marijuana, I hate to inform you, but that is a different plant. While they are of the same genus, the hemp cultivar only contains a small amount of THC. The amount of cellulose in hemp fibers is lower than in cotton, and it tends to have lignin in it. This makes it rougher and stiffer than cotton. But being long, at a typical 15mm length, and strong, it lends itself well to the production of ropes. I have never seen a yarn made of hemp in the shops I frequent, but I am positive there are some out there. 

A relatively newer cellulosic yarn is that derived from bamboo. These fibers are quite long at 38-76mm. Bamboo is super absorbent. The fibers tend to be smooth and round, leading to the soft feel of the yarn, as well as its low irritability, making it ideal for projects for anyone with sensitive skin, like babies. It also has a lovely sheen to it.

Coming up in Part 3-synthetic yarns!

References:

Stoller, D. Stitch'N'Bitch: The Knitter's Handbook 2003, Workman Publishing Company, Inc. New York, NY.

Crowfoot, J. Ultimate Crochet Bible 2010, Sterling Publishing Co. New York, NY.

Pratt, C. W.; Cornely, K. Essential Biochemistry 2004, John Wiley & Sons, Inc. Hoboken, NJ.

Mather, R. R.; Wardman, R. H. Chemistry of Textile Fibers 2011 Royal Society of Chemistry.

Le Couteur, P.; Burreson, J. Napoleon's Buttons 2003 Penguin Group, New York, NY.

  

A Yarn of Chemistry: All Ewe Knit to Know-Part 1, Proteins

One of my favourite hobbies has become the craft of crocheting, and I am in good company with my mum, gramma, close friends, and even Queen Victoria. I find this craft to be incredibly relaxing, giving me something to do while I try to relax my mind after working.  I can take it anywhere, it is super portable, as evidenced by the picture on the left, which is me crocheting in the Zurich train station while traveling in the summer. I will crochet while teaching in a help room and I found this very beneficial in keeping me calm when dealing with even the most difficult of students (which is NOT the majority of the students I teach) and also keeping me from getting bored when students didn't have a lot of questions without making me difficult to approach. You can hold a conversation, watch a movie, listen to a presentation all while crocheting. I do also know how to knit; however, I have yet to ever finish a knitting project. I find crochet to be faster, simpler, and easier to pick and put down-but that is my preference. A good many ladies in my department also crochet/knit, and like many things in life, this craft is filled with chemistry. 

When you start a craft like crocheting or knitting there are a few important things that you need, namely the hooks (if you are crocheting) or needles (if you are knitting) and yarn. Yarn is the general term for fibers that have been spun together. With the yarn comes a number of options and this can be daunting for a newbie. What is the difference? What does it all mean? What yarn is best for what project? What is the difference between wool and yarn? Well there are three main categories for yarn types: protein fibers, cellulosic (or plant) fibers, and synthetic fibers. Each type has pros and cons and is best for different types of projects. Because there are three different types, I have decided to break the entry into three different parts. Today's part is brought to you by protein fibers.

Protein fibers are animal in origin and are, as the name suggests, comprised of proteins, so before we can discuss protein fibers we need to discuss proteins in general. What is a protein? Proteins are large, 3-dimensional structures that are made up of amino acids (pictured on the right). There are 20 natural amino acids and they differ only at the position I have labelled "R". This R group gives each amino acid unique properties which, when many amino acids are strung together, will result in the protein properties. A string of amino acids makes a polypeptide. There are four levels of protein structure. The first level (called primary) is the specific sequence of amino acids strung together to make the polypeptide. This is determined by DNA code. The second level (called secondary) is localised conformations, which is created by the was that neighbouring amino acids interact with each other. The third level (called tertiary) is the over three-dimensional structure of the entire polypeptide. The fourth level (called quaternary) happens in proteins that are made of many different polypeptides. Now I find all of this very cool because muscles and hair are two very different types of proteins, but each are made up of the same 20 amino acids and simply differ by how those 20 amino acids are put together, which is what creates the overall shape, and thus the function. What I find even more awesome is that those 20 amino acids are dictated by the four base pairs in DNA. So depending on how those four base pairs are oriented in your DNA will determine what sequence the 20 amino acids in your proteins are put together, which will ultimately determine the protein function and that results in this amazing thing called life! But to carry on with my Ode to DNA I digress from the point of this entry, which is protein fibers. 

The first, and major, type of protein fiber is wool. Wool comes from sheep (and sheep-like animals). But not all wool is created equal. Different sheep give different wool. There is huge variation in the structure of wool (just like the variation in the animals themselves) and the overall structure is pretty complex. For the interest of crocheters and knitters I am going to focus on pure, fine wool. Raw wool can contain 30%-70% impurities. Pure wool is almost entirely protein. Wool is characterised by its diameter, length, and crimp (how curly it is). Smaller diameters, shorter lengths, and more crimp result in finer, warmer wools and super soft wools, really really soft wools (I can't stress that enough).

The basics of the fiber can be boiled down to the outside, which is called the cuticle, and the inside which is called the cortex. The cuticle is about 10% of the fiber and results in the surface properties of wool. What is most interesting about the cuticle is that the cells are put together like scales, i.e. they overlap, and this creates directional friction which means that the fiber is smoother (less friction) in one direction compared with the other direction. This is what makes wool so easy to spin into yarn, but also what causes it to felt and shrink because the scales cause the fibers to get entangled and thus felted. The cortex results in the overall structure of the yarn. Depending on how the cortex proteins are put together will influence the amount of crimp in the yarn. 

The protein that makes up wool is called keratin. Wool is over 80% keratin. What makes keratin interesting is that it is high in the amino acid cysteine. The R group in cysteine is CH2SH. The remaining amino acids cause the protein to adopt a helical structure and then the cysteine amino acids in two protein strands bond together. The result is two protein fibers that are coiled together and then cross-linked through sulfur bonds, making them pretty strong. (Side note: sulfur-sulfur linkages are also what give vulcanised rubber its strength.)

Let's compare types of wool: 1) merino wool is soft, not terribly expensive, but does pill. Its fibers are 17-25 micrometers in diameter. 2) Mohair-this is wool that comes from the angora goat (not to be confused with angora wool, which is made of bunny fur). Mohair is a little coarser at 25-45 micrometers in diameter, but is quite fuzzy. I have used it in a blend for a sweater, super nice. 3) Alpaca-oh how I love thee alpaca. Alpaca wool is from, shockingly, alpacas. On the left I have a picture of my Queen Victoria scarf that I made using alpaca. It happens to be the second softest yarn I have EVER put my hands on. Alpaca is 18-25 micrometers in diameter (remember smaller is softer and warmer) and I can tell you that this little number is very VERY warm, which is helpful up here on the prairies. Actually, this particular pattern is nice with a yarn like this because the space between double crochet clusters keeps you from over heating. I have another alpaca scarf that is much more densely crocheted. It is also super soft, but I won't wear it if it is warmer than -10 C because it is just too hot. 

4) Cashmere-and on the right we see a picture of the softest yarn I have ever felt. Cashmere is combed from the bellies of cashmere goats and is very fine, at no more than 19 micrometers in diameter. Naturally this makes it more expensive (those little 50g balls are $26 CND each), so I have a very special plan for those two little balls. Now both alpaca and cashmere are less durable than merino wool, something to consider when planning your projects. 

The other type of protein fiber is silk, which is produced by some very specific moth larvae (a.k.a. silk worms.) Basically when it is time for those larvae to morph into moths, they excrete a thread of the protein fibroin out of its head and glues it together with a protein gum, wraps about 2 Km of it into a cocoon, under goes its metamorphosis and leaves the shell of its cocoon behind to be unraveled and degummed and sold as silk. Since it is already a thread, silk doesn't need to be spun to form yarn, the silkworm already took care of that. So instead of keratin (the protein in wool), silk is fibroin. This protein has very little cysteine in it, and therefore doesn't have sulfur bonds holding the fibers together. The main amino acids in fibroin are alanine and glycine, which are the smallest of the amino acids. This means that the silk fiber is more crystalline, and less stretchy. It has more tensile strength than wool, but tends to be more brittle. These fibers are 15-25 micrometers in diameter. This makes silk quite soft. It is also quite light. But it is also quite expensive. It is shiny though. It makes a good choice for a shawl or wrap. 

Coming up in part 2-cellulosic fibers: cotton, linen, bamboo.

References:

Stoller, D. Stitch'N'Bitch: The Knitter's Handbook 2003, Workman Publishing Company, Inc. New York, NY.

Crowfoot, J. Ultimate Crochet Bible 2010, Sterling Publishing Co. New York, NY.

Pratt, C. W.; Cornely, K. Essential Biochemistry 2004, John Wiley & Sons, Inc. Hoboken, NJ.

Mather, R. R.; Wardman, R. H. Chemistry of Textile Fibers 2011 Royal Society of Chemistry.