Archives for July 2017

The Sound of Music

If you’ve ever played a musical instrument for more than a few years, you’ve probably found yourself thinking about an upgrade.  ‘Imagine how good I would be,’ you think to yourself, ‘if only I had that platinum flute instead of this silver coated one.’  You scrimp and you save, maybe for years, and you finally get the flute, you play it, and you know you sound better than you ever have.  Or do you?

 

Widholm, a researcher in Austria, set out to determine just this fact.  He assembled seven flutes of varying materials in the same model, and asked professional Viennese flautists to play on each of them.  Analyzing the sound waves, Widholm found that the material of the flute’s body made little to no difference on the practical sound of the instrument.  So, what we would normally perceive as a vast improvement in playing is really just a placebo effect as a result of having a new instrument that we perceive will make us better.

Flutes made of different materials which (objectively) have no real difference in quality

Sometimes, though, material does matter.  Consider the violin, one of the most famous instruments ever invented, championed by creators like Stradivari and Guarneri, revered as the heart of the orchestra.  Its full bodied sound and extensive range are in part because of the properties of the wood it is made of.  Similar to the study done with flutes, the type of wood isn’t as influential as one might think.  The real catch is with the wood itself.  Wood is an elastic anisotropic material, which means that along the grain, the vibrations can go for three times as long as across the grain.  This basic principle is what gives violins their characteristic shape, and of course their sound.  Violin artisans trying to make new violins from new materials face the issue of replicating this elastic anisotropy, and so are confined to certain materials, such as composites which can be chemically altered to contain such a microstructure.

A carbon fiber violin, which, thanks to its elastic anisotropy, sounds nearly the same as a wooden violin

With recent developments in 3-D printing technologies, even plastic can be used to make musical instruments, allowing anyone with a 3-D printer to construct their own musical instrument.  These instruments are still able to sound good often because of which part of the instrument is vibrating.  If it is a string or the player’s mouth that is vibrating rather than the instrument, nearly any material could be used.  For example, a metal trumpet and a wooden trumpet would sound nearly the same.  Some examples of this technology in use include a 3-D printable ukulele, as well as ocarinas, recorders, and even a full-sized guitar.

This 3-D printed guitar would be very difficult to print, but it shows the possibilities of future advancements

Music is around us all the time; stuck in our head, playing in the halls we walk, setting the scene in the movies we love.  It has been an integral part of the human experience for centuries, and it doesn’t show any sign of stopping now.  Whether or not materials make a difference in the instrument, the instruments make a difference in our lives.

 

Thanks for reading,

 

Natalie

Printers are a Girl’s Best Friend

Additive manufacturing these days is more of a buzzword than anything else.  Yes, everyone has heard of the 3-D printer, but to what extent does the general populace understand its complexities?  In today’s post, we’re going to outline one of the different types of 3-D printers available and under development, as well as the possible applications of additive manufacturing and how these machines came to be.

 

A chart of the numerous different kinds of additive manufacturing

Especially in recent years, types of 3-D printers have exploded, so we’ll just go through the most major type today.

 

The beginning of it all: plastic.  The first 3-D printers printed plastic because of its ready availability and relatively low melting point.  Printers didn’t need special tips or super heat-resilient bases, they could print layer upon layer of plastic with technology that almost anyone could assemble.  As plastic 3-D printers have advanced, their speed and accuracy have increased, augmenting the practicality of these machines.  There are two main types of plastic used in this type of printing: ABS and PLA.  ABS is better for outdoor applications, it is a sturdier plastic which requires a higher melting point.  PLA is suited for indoor projects which won’t be exposed to the elements, it is easier to work with, having a lower melting point, so is much preferred in many communities.  It all sounds so easy to talk about it now, but how did these machines actually begin?

 

In the 1980s, a man named Chuck Hull was fooling around with stereopolymers, liquid materials which turn to solid when exposed to UV light.  After a long troubleshooting process, Hull had his process, and patented stereolithography, the basis for modern 3-D printers.  He soon started his own company focusing on this new technology, and it is still going strong, innovating new types of printing at every turn.

Chuck Hull, inventor of 3-D printing

So, why are 3-D printers important to society?  Well, the reason they were invented was to find a new method of manufacturing, one that could produce parts more efficiently or more soundly.  Truly, 3-D printing has maintained this goal through the present day, as different printings can change microstructures for different types of strength, or even produce pieces that never would have been possible via traditional manufacturing methods.

Items like this would be very difficult, if not impossible, to produce via traditional manufacturing methods

3-D printers are also associated with the democratization of manufacturing.  The beauty of 3-D printing is that almost all of it is open source, especially with plastic.  Brands like Prusa sell kits online for small amounts of money, containing all the parts one needs to build their own printer.  I can vouch for the efficacy of these kits, I built my own printer last summer.  In addition, websites like Thingiverse share thousands if not millions of free patterns, both for fun and practical use, so that anyone can make things in their own home, using a technology that was, at one time, unimaginable.

 

Until next week,

 

Natalie

A Tale of Two Hobbies: Part 2

Please Note: This post is a continuation of last week’s entry, “A Tale of Two Hobbies: Part 1”.

 

One day, Samuel Kistler, a farmer, was spreading some jelly on his toast when he wondered what was holding that gel together.  It occupied a space somewhere between a solid and a liquid, and so Kistler hypothesized that by removing the liquid, he would see the solid framework that provided structure to the jelly.  Kistler consulted some scientists, and both agreed that by supercritically drying the gel, they would be able to isolate the solid structure within.  Some of the first tests were on egg whites and fruit jellies, and the material they discovered was aerogel.  This material has amazing properties; it is a powerful insulator, and the world’s lightest manmade material.  Its structure is pockmarked with holes, and looks something like this.

Aerogel microstructure

Diagram illustrating the principles behind aerogels’ insulative properties

 

Aerogels have recently been developed for numerous interesting applications.  In the 1980’s, a meteor shower was going to pass close to Earth, and scientists wanted to collect samples so as to better understand our universe.  Puzzled, they searched for a material that could withstand both the immense force and heat of collisions while also effectively collecting the material.  They found their answer with aerogels.  Because of their insulative properties and their many holes, particles could collide with the aerogel without harming it, and would remain in the aerogel for further analysis back on Earth.  This was called the Stardust mission, and it is because of that innovative usage of aerogels that we collected the first ever samples from a meteor shower.  Additionally, aerogels have been highly developed as insulation for houses, where they can be many times as effective as traditional insulation.  There are jackets whose linings are composed of aerogels.  The initial prototypes for these jackets were so effective that when they were worn climbing Mount Everest, climbers became too warm and had to unzip.

 

Aerogels can also be given properties traditionally associated with metals, such as shape memory.  At Missouri S&T, researchers have been working to improve this technology.  When these particular aerogels are deformed from their original shape, just a little bit of heat will return the material to its original position.  This technology’s applications include projects as monumental as biomimetic hands, which, due to the flexibility and versatility of aerogels, could be groundbreaking.

Time lapse photo of a shape memory aerogel returning to its original position after a deformation

A biomimetic hand utilizing shape memory aerogels

 

This diversity in the applications of aerogels are due largely to the wide range of compostitions they can have.  Aerogels range from silica, one of the first materials developed, to carbon, metal, and metal oxides.  Each type of aerogel has different properties, and open the pathway for new developments.

 

It is amazing to think that such important developments in the field of Materials Science and Engineering could come from such simple hobbies as canning and origami, but this is the case.  We never know where the next development will come from; it could feasibly be hypothesized from another hobby, perhaps even one of yours.  You never know.

 

Thank you so much for reading, and I look forward to presenting more intersections of history, MATSE, and anthropology in the future.

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