When in Doubt, Lasers

When you want to see how anything works, whether it be a car, plant, or liver, you look inside. Everything fun and important is more than skin deep. The very first way of doing this was with dissections; getting your hands all dirty and such. In more recent years, we have progressed past this less precise method with technology like CT scans (that utilize x-rays) or MRI (which uses radio waves as well as a magnetic field). However, both of these methods have some serious drawbacks to them that restricts their use in certain fields. For instance, CT scans create images based on the density of materials, so if a specimen has a bunch of structures of similar densities, they can become very difficult to tell apart. MRIs on the other hand, are huge, clunky, complex, and crazy expensive (the bottom shelf MRI scanner costs more than $150,000, and they very quickly go up in price).

Clearly, the only way to solve this is with lasers. I mean, it worked with sharks.

Much Better.
Image Courtesy of ThinkGeek.com

Benjamin Hall, an undergrad who was working part time at the ARL (Applied Research Lab) here at Penn State, has been working with a technique called Laser Ablation Tomography (even the name sounds cool) to image things. The technique is pretty simple: you put an object like a root (they love doing roots and other plants stuff) on a moveable platform, fire up your lasers, and vaporize your sample layer by layer. At each layer, you can take what is essentially a photograph, allowing you to stitch together a 3D model of the sample at the end, complete with the internal structures. It's sort of like those 'cross section of a brain' exhibits you see at some museums, only with much much thinner slices. What results is a model like the one you see below. Using these models you can explore the sample as much as you want with extreme precision (~1µm).

Video Courtesy of L4iS LLC

Plant structures are clearly not the only thing you can model with this technique; it could also be used for things like material analysis. On denim jeans for example! On a side note, on the gif of the denim below, if you look closely you can see little mini 'fires', which would make sense as denim is flammable and the lasers are pretty much burning the denim away layer by layer – its just cool to see that that was captured on the model.

Video Courtesy of L4iS LLC

Since Mr. Hall started developing the process he has started his own company, Lasers for Innovative Solutions, based here in State College. The company focuses on services for agricultural businesses, as the technology allows you to quickly phenotype specimens (see what physical traits they have) that would be difficult to do in another manner. For example you could see just how one of your new types of sorghum is developing differently compared to other varieties.

Image Courtesy of L4iS LLC

Today's world is all about speed. We have seen this most recently with rapid prototyping using 3D printing, and this Laser Ablation Tomography is another way that research and development can occur at faster speeds. Now data can be acquired on materials or specimens without having to stain or otherwise prepare them (remember how annoying it was trying to prepare slides in biology in high school?). It certainly will not replace other imaging technologies, but there are certain applications where this newer technology is superior both time and quality wise. 

Penn State applied for and got a patent on the process (with Benjamin Hall as co-inventor), and the technology is being used both in Hall's private company as well as in research labs at PSU, most notably in the department of plant science.

Graphene: The Wonder Material

Most of you are probably familiar with graphene, that fancy new sheet of material that is one carbon atom thick, 207 times stronger than steel (by weight) and can conduct electricity. Many researchers tout graphene as the 21st century's "wonder material," able to be crafted into the next generation of electronics (beginning the 'post-silicon' era of processing), composite materials (materials made of multiple components with differing properties), as well as countless other applications.

Image Courtesy of Wikimedia

However, there are a few snags to tackle along the way before it gets into the practical realm. In order to tackle some of these problems and to gain a better understanding of the weird properties that come with essentially two-dimensional materials, the Center for Two Dimensional and Layered Materials (2DLM) was established in 2013, bringing together faculty and students from PSU as well as other institutions. The center is working on many exciting projects, but instead of making a separate post for each one, I'll briefly go over a couple of them in this singular post.

One of the major challenges to the use of graphene in industrial applications is the fact that it's just so hard to make a large, pure enough sample of the stuff. One method that has been brought up is called 'intercalation,' which basically means to get a sample of graphite and shove in a bunch of non-carbon atoms in order to more easily pull the sheets of carbon apart. On the molecular scale it would look like the image below. Previous attempts at this method had to use very strong agents that ended up ruining the material, but a group in the 2DLM was able to devise a way to process the reaction without them, meaning that now the reaction just needs to be sped up in order to get the process good for larger scale production.

Image Courtesy of Mallouk Lab/Penn State

Looking to an entirely different focus, the center also has a team that is working on a cool application of graphene: stretchy yarn! By weaving together a bunch of graphene strings, a fiber was created that is much superior strength-wise than other carbon fibers that have been experimented with.

Image Courtesy of Terrones Group/Penn State

Now this might not seem like much, but this carbon string has an abundance of applications. For instance the string may be used as a replacement for copper transmission lines, as graphene conducts electricity better than copper and is also much lighter. It's just better all around pretty much. One could also make trip wires out of it, if that's your thing.

The Center for Two Dimensional and Layered Materials is doing some pretty exciting stuff here at Penn State, and while I only was able to gross over two of the things they are working on right now, there is much much more (their publication list is pretty darn impressive). Graphene is an incredibly exciting material that will certainly change the way many of the things we use now are made. Get ready for the future guys, it's coming pretty fast.