Please click the following link or the above picture to redirect to our new website: Engineering A Future !
Be sure to subscribe to our new website & follow it please!
Please click the following link or the above picture to redirect to our new website: Engineering A Future !
Be sure to subscribe to our new website & follow it please!
Well, it appears that it has become time at last for Team UV to end its journey. Today marks the 345th day that TeamUV.org has been active and I can guarantee you that every one of us here at Team UV has throughly enjoyed and cherished the 29,676,840 seconds that this blog has been running (at the time of publishing this post). During this time we have had the incredible opportunity to share some of our own research and, far more importantly, help to inspire interest in the STEM fields amongst the general public with visitors from 115 countries for a total of nearly 8,300 views and well over 200 likes from 114 WordPress followers, our email followers, and many others.
This blog has far exceeded our expectations and for that we have all of our family, friends, supporters, and readers to thank. Without all of you, we would have never been able to accomplish what we have over the past year. I have been honored to lead this team and to have the chance to interact with all of you on a daily basis, all-the-while growing with my teammates and watching them progress through the challenges of the last 15+ months of our senior project. I believe that I can speak for all of us when I say that the experience of writing to all of you here at Team UV is not one that any of us will soon forget. These are the kinds of memories that stick with you.
The experience afforded to all of Team UV by sharing with you all over the past year will serve us well in the future as we push onwards and upwards in life and face new challenges, and I sincerely hope that our time here will serve all of you in the same way. From compressible flow regimes to programming Arduinos to biomedical diagnostic tests to 3D-printing makeup to insects with gear-like rear legs, we truly have covered a whole lot of incredibly diverse topics here at Team UV, but we have not even begun to scratch the surface of what the world of engineering has to offer. Part of the beauty of the world of engineering is that it truly is limitless. Boundaries to the engineering mindset do not exist and physical barriers to what engineers can do simply serve as challenges for scientists and engineers alike to accept. We hope that we have begun to shed some light on this reality and on the opportunities available within the STEM fields.
We set out hoping to reach just one person out there and help to inspire them to go on to pursue STEM-related careers or simply just to spend some time everyday thinking scientifically. I personally have heard from numerous people over the past year about how we have made a difference within their lives or the lives of their friends or families. I have also heard similar stories from my teammates, and that is the golden metric.
I am beyond proud of my team and what we have been able to accomplish and look forwards to continue to share with our readers about STEM over at our next project: EAF. For those that do not know, Engineering A Future (EAF) is a website that I originally intended to launch back in December 2012 with the goal of inspiring interest in the STEM fields amongst the general public…sound familiar? After preparing and stockpiling posts for a few short weeks, my Winter Break ended and the Winter 2012 quarter started in at Cal Poly Pomona (CPP) and my plans fell apart. I had become far too busy, did not have any help, and simply put had never done anything like EAF (or TeamUV.org) before. EAF was created with good intentions, but was not planned for properly by me, but I can assure you, that has all changed.
Flash forward three years and EngineeringAFuture.com will be relaunching on Monday (July 13th, 2015). This time the website is ready to go, as is the team. I have spent the past few months preparing EAF for its launch and am excited to cut the ribbon Monday morning. EAF will follow the same idea that TeamUV.org has, but will take it to a whole new level. EAF has been optimized with one goal in mind: to get as many people as humanly possible excited about STEM. Crazy, right? Well I believe that I have the perfect team to do it and that we are more than prepared to hit the ground running, help people to learn, learn (ourselves), and just have fun with it. Most of Team UV will be carrying over to EAF: Abraham, Ketton, and Andrew will all be bringing their massive brains, awesome outlooks, and passion for STEM-blogging and connecting with the community over to EAF. Unfortunately, Ben will not be continuing with us at EAF and so we wave a somber goodbye to a valued team member and friend. But fear not, while we may be losing a teammate, we are also introducing some awesome new features.
First is the style of posting. EAF will be posting three times a week (just like Team UV has been), but this time we will be posting on Monday, Wednesday, and Friday. Posts will go live at 0800 (purely so that our followers who check the site early will already have the content up to read, rather than having to wait around for two hours) and the social media (Facebook, Twitter, and Instagram) sharing of the posts will be sent out at 1000 hours (two hours later). Post categories have been almost completely revamped and the new categories will consist of:
On top of this, the new website is far more aesthetically pleasing, has many cool features and pages, and will hopefully mean a much more awesome experience for our readers and followers. Lastly, we have some very cool ideas in the works for some awesome new types of content that will launch later on down the road. The website is currently having its finishing touches put on with the About EAF page being finished up offline before transferring it to the site this weekend, a few member bio pages being finished up, and the graphical interface being tweaked a little bit more for Monday’s launch.
In closing, we want to thank our readers/supporters/followers for joining us along this journey and sincerely hope that all of you will continue to follow us over at EAF starting Monday! On Monday, a post redirecting our readers to EAF will be published.
Thank you for your time
Well looks like the time has come to say farewell. This has definitely been a fun ride here at TeamUV.org and I can definitely say I will not forget it. I honestly want to thank everyone who has supported us this entire trip whether it be reading our post, donating, commenting, or any kind of support you have given us. I just hope that we were able to shed some light on all of the interesting items that people just like us have created in the STEM field. We all have learned a lot from the beginning of this project (SHIELA-D) up til the end (DORY) and that experience is something that we will never forget.
You know, anyone can put up an article. But when you put up an article and see that people are coming to the site, reading it, and leaving comments, it is such a great feeling and once again I want to thank everyone who supported us no matter how small or large. As for the “For Now” part, I will be putting up articles for Engineering A Future for a little while so feel free to come, kick back, and read some more articles!
From the coolest guy in the group…..You Rock!
Abe here. Just wanted to thank everyone who donated to our project, read our articles, or simply supported us along the way. We accomplished a lot with this project, visited a lot of places, and even represented our department at the Engineering Project Showcase. More importantly, I am more than pleased with what we learned by tackling this project. I think everyone on the team got a glimpse of what being on a real engineering team was all about and we can now take this experience to industry or wherever we go. I hope that what we have done here inspires you to do something you’re passionate about and give it your all. In closing, I will continue to write for Engineering a Future for the next few months so follow us there!
Goodbye nerd friends. I’ll see you later this month on EAF!
It has been quite an adventure writing the posts for this site, I know I have learned a lot, and hopefully you have too. While this blog catered mostly to people interested in the science technology engineering and math fields I did what I could to make it accessible to all. One of the best ways to learn something new is to try and explain it, so thank you for letting me learn by explaining to you.
Hopefully most of you will continue on the Engineering A Future. I will not, my blog writing journey has reached its end here. It was fun while it lasted stay curious and stay creative, always stretch your minds to the limits!
So the day has finally come; my last Team UV blog post. It’s been a true pleasure writing about STEM topics for all of you to enjoy. Blogging for this site has given me a venue to express my engineering interests, as well as way to see what my fellow Team UV members are in to. As Mechanical Engineering graduates who completed the same basic curriculum at Cal Poly Pomona, it’s fascinating that we are all interested in different fields. I can’t wait to see where the five of us will go in our careers.
I’m excited for the next chapter with Engineering A Future (launches Monday July 13th) and the chance to share my interests more deeply with you all. As of now, I will be posting once a month on EAF about my favorite topics: robotics, the energy industry, and electronics!
See you all on EAF!
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be Ketton’s last Open Mind post here at Team UV, but not to fear, there is still one week of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
We have been yearning for the hoverboard technology ever since it premiered in series like Back to the Future and Real Adventures of Johnny Quest. But, due to the complexity of the underlying technology, no hoverboards have yet been able to accommodate a real person during flight. It has largely been agreed that the future hoverboard’s levitation effect will come from the application of electromagnetic levitation rather than any propulsion. But in addition to the electromagnetism, the new board also uses liquid Nitrogen in some capacity. The new attempt at the hoverboard is called Slide and it can lift itself off the ground and carry a person. Not enough technical details regarding the board of our dreams are available, and the sole source of information is a video released by the Tokyo branch of Lexus, the company behind this invention. The project is a part of the Amazing in Motion campaign by the Lexus company that has produced an 11 foot tall android, a swarm of quadcopters and mannequins performing in Kuala Lumpur.
We see in the video (below) how a young man is getting off from his boring regular board and then moves towards the Slider board. It really seems to be levitating in thin air. It seems to be a remarkable feat of engineering and a long-awaited ride for us. Due to the brand image of Lexus, it is unlikely that it is an edited video. The video is real but to see an actual hoverboard is mesmerizing. I bet there are many technical difficulties to overcome before we can actually see it. There had been an attempt of making a working hoverboard before as Kickstarter attracted the Hendo hoverboard that could levitate and move across a floor of some conductive material to create a secondary field.
The Lexus spokesperson told the media that there won’t be any disclosure of information before the end of the month when the board could be unveiled for the cameras. However, we cannot help but feel suspicious about the whole thing. The electromagnetic levitation requires a particular type of surface to float on. In the video, the guy appears to be doing so on concrete, which doesn’t seem to make sense. Maybe there is a secret to the smoking sides of the hoverboard. They must contribute towards its function in some aspect.
Check out the video below and see what all the fuss is about!
Today, Brian will be filling in for Ketton due to last minute scheduling issues, we apologize for the post delay.
Ferrofluids are quite complex fluids that display interesting behavior in the presence of magnetic fields. These ferromagnetic fluids are created through the colloidal suspension of ferromagnetic particles of the nano-scale. What does this all mean? In simpler terms, you essentially take tiny (nano-scale, or on the scale of a nanometer/a billionth of a meter; think the size of the base width of a single strand of DNA) magnetic particles and disperse them homogenously (or evenly) throughout a carrier fluid in a way so that the particles are fully wetted (meaning that the particles surfaces are fully coated by the liquid, without other particles in contact with them).
Once the ferrofluid has been created, the next step is as simple as subjecting the fluid to a magnetic field, at which point the ferrofluid becomes magnetized. As the ferrofluid begins to be affected by the magnetic field, it wants to follow this field and comply with its geometry; basically, the fluid wants to become shaped like the field it is being subjected to, but there is a problem: the fluid has surface tension. Because the fluid has cohesive bonding between liquid molecules, the molecules are very strongly attracted to each other on the molecular scale. This should make sense to you, as when you run your hand through water (for example), you are able to readily cause bulk disturbances (you can split up the water on the large scale), but try as you might, you will not be able to split the water apart on a molecular scale (the smallest you can get water to by hand is tiny visible droplets, which are still collections of a ridiculously large amount of water molecules (on the order of sextillions, or thousands of thousands of thousands of thousands of thousands of thousands of thousands!).
Because of the aforementioned strong attraction between the liquid molecules, fully immersed liquid molecules are pulled on by other molecules in all directions, as shown above in the picture. However, the molecules on the surface are only pulled on by molecules around and below (but not above) them, leading to a breach in the equilibrium and causing the water to be pulled in the direction of the rest of the water (hence the curved water surface exhibited in the above diagram). So, armed with this knowledge of how surface tension works, we can revisit the ferrofluids and figure out what is going on.
The magnetic field wants to push the ferrofluid outwards, but the ferrofluid itself wants to pull itself back inwards towards the liquid base due to the surface tension, all while gravity is also resisting the spike formation (this kind of interaction is explained through the normal field instability). At some point all of these forces equate and the fluid is said to be in equilibrium. The result of this? Really cool looking spikes in the ferrofluid as shown above. This gets even cooler when sculptures are created (as in the top picture) by using shaped bases and manipulating the shape of the magnetic field. It should be noted that art is most definitely not the only application for these fluids; in fact, ferrofluids also find application as: liquid seals around the shafts of spinning hard disks/drives, as a convective heat transfer fluid for wicking away heat in small scale and low gravity application, as an imaging agent in some medical imaging techniques (especially magnetic resonance imaging, MRI), as friction reducing agents, as mass dampers to cancel out vibrations, and even as miniature thrusters for small (nanoscale) sattelites!
So there you have it, another awesome engineering phenomenon! Please tune in Sunday for Ketton’s last Open Mind post and remember to continue following us at EngineeringAFuture.com when Engineering A Future (EAF) launches on Monday, July 13th! Enjoy the video below, created by altering the magnetic field in a ferrofluid sculpture!
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be Ketton’s last Well Read post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
Before we go any further into the purpose of the “breather hole”, we will first check out how a window in a pressurized passenger cabin is set up. As shown in the Boeing 737 maintenance manual (the most widely produced jet airliner in aviation history), the window structure consists of three layers of acrylic – a tough, transparent and flexible resin – although only two of them have an actual structural function.
These structural layers are the intermediate and outer ones – while the inner layer (called “scratch pane”) only serves as a buffer between the passengers and the structure of the window itself. These layers prevent the cabin from reaching the external pressures that, depending on altitude, are too low for the vital functions of the human body.
Basically, the primary structural window guarantees the cabin remains at a constant pressure equivalent to an altitude of 7,000 feet, which is still quite acceptable for the body. However, in most cases, only the last acrylic layer is responsible for ensuring such conditions; the intermediate layer is just there for extra safety. Having said that, let us get back to the mysterious little hole.
As can be noted in the diagram shown above, the breather hole is located in the middle layer of the window. This little puncture acts as a bleed valve ensuring that the pressure between the last two layers and the cabin always remains the same. This is necessary as a way of preserving the middle layer (the extra safety one) so it is only exposed to severe pressure differences in cases of emergency – that is, if the last layer the window is fractured in some way.
The breather hole also serves to prevent freezing and fogging between the outer layers of the window. Of course, that doesn’t always work since it is not rare to find photographs showing some frost on the windows.
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be Abraham’s last Open Mind post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
Let’s face it, your house was probably built over half a century ago. It has the appeal of an old high school sweatshirt: comfortable but covered in bleach stains. The future is now! Time to design some new homes that will last longer, are more affordable and sexier than your parent’s house. Engineering can add a lot of interesting choices to your home. Here are a few of mine.
Thanks for reading, hope this helped you make some interesting choices for your home and fashion choices of the future.
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be Abraham’s last Presentation post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
Have you ever heard of Ultrasonic Melt Treatment? Me neither but I did some research and found some pretty interesting things. Ultrasonic Melt Treatment (UST) is essentially the addition of high frequency acoustic waves to a liquid melt of a metal (typically aluminum) to induce acoustic cavitation. Please note that acoustic cavitation is essential. The acoustic waves introduced into the melt have to be at a high enough amplitude and frequency to alternate pressure above the cavitation threshold to create cavities in the melt. Essentially what is happening is the rapid formation and collapse of bubbles in the melt which can have some beneficial effects before, after, and during solidification. The acoustic cavitation is said to activate the melt which means that it will accelerate diffusion, wetting, dissolution, and dispersion which will directly affect degassing, solidification, and refining of metallic alloys. Now if you’re into metallurgy this all sounds incredibly interesting, but if you’re not I will try to explain what each of these mean.
Degassing is one of the primary uses of UST in which the concentration of a certain gas will be lowered in the melt. In light aluminum alloys, acoustic cavitation will cause the growth of fine bubbles in the melt on the surface of non-wettable oxides. As a result, cavitation will cause direct diffusion of hydrogen into the bubbles from the melt. Acoustic flow will assist in floating these bubbles to the surface and out of the melt. The benefits of degassing are that lower porosities can be achieved and thus higher densities in the final material. It has also been found that lowering the concentration of hydrogen in aluminum alloys will raise the ultimate tensile strength and ductility of the material. It is noteworthy that one study concluded that UST is the best amongst other commercial degassing techniques in terms of effectiveness in degassing and in time of treatment.
Melts are usually cleaned of inclusions before final treatment. Aluminum melts usually use mesh filters but in order to filter out very fine particulates, multiple layers of successive filters need to be used. This is often not allowed because of the restriction of capillary action of the liquid melt through the filters, however with the use of UST during filtration, a sonocapillary effect is produced. This sonocapillary effect is caused by the cavitation field that is formed which allows for the melt to freely pass through the multiple layers and disperse unwanted oxides.
One of the most important benefits of UST is that it produces non-dendritic structures during solidification. A dendrite is a branched tree-like structure that grows during solidification of liquid metals (fun fact: dendritic solidification is actually what is behind the unique shape of snowflakes!). As mentioned earlier, acoustic cavitation allows for the wetting of non-metallic impurities in the melt and these become sites for nucleation (aka the start of solidification). Because these nucleation sites are ahead of the solidification front, there is no growth of dendritic structures.
As non-dendritic solidification occurs, the grain becomes only a fraction of the matrix structure so there is refinement in grain size. It is important to note that grain size is only a function of cooling rate in these conditions, therefore this method of refinement is applicable to all metallic materials. One of the major benefits of materials with non-dendritic structures in Al-Si-Mg systems is that they are able to deform very easily at a semi-solid temperature ranges. Essentially what this does is allows the grains to rotate and slide relative to each other without the interference of the dendritic braches. This can dramatically improve mold filling by lowering the viscosity. The apparent viscosity of non-dendritic melts at the semi-solid temperature range is lower than that of the regular melts and is comparable to that of olive oil, at least for aluminum.
Overall there are many benefits to Ultrasonic Melt Treatment in aluminum alloys such as degassing, refinement of grain size, and filtration. Although UST has only been extensively studied in non-ferrous alloys, recent research has been done on its effects in low-carbon steels and even epoxy based nanocomposites. In all cases it is the acoustic cavitation, duration of the treatment, and force of frequency that dictate the effectiveness of UST. Hopefully this taught you a little bit about UST. For more info, please refer to the paper by Eskin, G.I. “Broad prospects for commercial application of the ultrasonic (cavitation) melt treatment of light alloys”.
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be Abraham’s last Well Read post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
Over the last few years 3D printing has gone from a obscure manufacturing process into a mainstream solution for everyday problems. The reason for this transition is mainly due to the types of materials that are able to be extruded out of a hot-end of a 3D printer. PLS was first used because of low melting point but with advances in hotend technology, materials such as ABS, nylon, polycarbonate, PEEK and more can be used in additive manufacturing. The more materials you have to work with, the more applications your product can have and that’s exactly the beauty of 3D printing. It is amazing for prototyping and making unique parts that you cannot find anywhere else.
The average 3D printer’s extruders have a temperature range of about 180-325°C, however, this limits the types of materials that can be used. A small Israeli company called Micron3DP has been experimenting with glass as a medium for 3D printers and (as of today) has announced that it has had a successful test using molten glass! Now if you know a little about materials, you know that glass and ceramics have extremely high melting points which means using them as a medium for a 3D printer requires an extremely hot extruder. And that’s exactly what they did.
Micron3DP’s tests were done using “soft” glass at a melting point of 850 °C and borosilicate glass at a melting point of 1640 °C using an innovative way of 3D printing in an extremely hot extruder. The process is analogous to that of printing with molten thermoplastics on a Cartesian based machine, one layer is laid down and cooled rapidly before the next layer is set down.
If you have ever 3D printed anything, you know how empowering it feels when you are able to create exactly what you want and use it immediately. Soon you can add glass to your arsenal and you will be an unstoppable creative force. Glass has very unique optical, corrosion resistant, and temperature resistant properties and this new technology and process will hopefully harness the power of glass for use in the medical industry, aerospace industry, and even the art industry. Now this breakthrough is so recent that as of June 22, 2015 (yesterday) the company is still seeking investors to help them further the technology. If you want to get started on the 3D printing game, here’s how you can make your own 3D printer for cheap:
For more updates on glass 3D printers, visit Micron3DP’s website here: http://micron3dp.com/
Summer is here and with it brings barbecuing season. While the average charcoal BBQ may seem like a pretty simple appliance there is some solid engineering behind its design.
First let’s look at the charcoal briquettes. An engineer took chunks of wood and organic matter and heated it up in the absence of oxygen to produce an energy dense fuel that is fairly clean burning. This process is called pyrolysis and it removes all the moisture and fumes so that the avid BBQ enthusiast will be able to cook their food without coating it in a black smoke of tiny particles.
The BBQ itself is designed to control the combustion process. By opening and closing vents the user is able to regulate the flow of oxygen to the fuel. This directly affects the combustion rate, the rate at which energy is released in the form of heat.
And, as with any cooking process, heat transfer is an important consideration. When the coals are glowing hot they are emitting a lot of their heat as radiation. Radiation requires a direct line of sight and this is what causes one side of your food to get a nice sear on it before you flip it. When the lid to the BBQ is closed the air inside heats up and this allow for some natural convection, heat transfer from the hot air moved by its change in buoyancy (hot air rises). There is also some conduction, from relatively still hot air and the heated metal components that compose the grill (not to mention conduction through the food itself). Each one of these modes of heat transfer provide a different aspect to the grilling process. Radiation causes the sear, conduction is responsible for the grill marks and convection is responsible for the even heating and temperature of the food.
A deeper understanding of any process can lead to better results and engineering gives perspective into many of these processes. As far as grilling goes most of it can be picked up from experiences, but isn’t it more fun to know why these things happen! Happy Father’s Day to all the dads out there, no matter who does the grilling!
Creativity is a huge part of being an innovative engineer. Thinking outside of the box it what has allowed the human race to advance their science and technology to the levels that we see today. While there are a few exceptions most of the engineering courses taken to receive the final degree focus on building a foundation of knowledge. These classes are designed to give a future engineer a solid base to develop ideas from. Creativity is a difficult thing to teach because it comes to everyone in a different way. Here are a few things that I do to help me become more creative.
The biggest thing, at least for me, is that I keep an idea notebook. It is just a small composition notebook that usually remains in my backpack, but when ever I see something that is frustrating or looks like it could be improved I jot it down. This way I have a list of problems that need solving.
Another thing for me is staying in touch with the advancements in technology by reading science blogs and sometimes the journal articles that they refer to. This keeps me learning and stretching my mind into new areas. Some of these new ideas I can tie to the list of problems that need solving and then I can start designing as system that would solve this problem.
Practicing the creative process is one of the best ways to get better at it. By seeing a problem and then attempting to design a system, either as a thought exercise or on paper, more problems come up, which in turn need solving. By going through this process, solving problems, learning new things, applying these things to existing problems, new and innovative solutions arise.
This is the method that I use to come up with new ideas and inject creativity into my work. Please feel free to comment with methods that you use. Everyone’s mind works a little differently and there are so many different ways to find inspiration.
Friction is one of the most important and unappreciated forces in nature. It is the reason cars’ tires grip the road and handle turns while remaining in control. It is also one of the major reasons your car’s gas millage isn’t what it could be. What if there was a way to keep the helpful aspects of friction while removing the bad ones.
The oil in your car serves as a lubrication system which reduces friction quite a lot by coming between two surfaces that are rubbing together. This system allows cars to have long lives without wearing out, and gives pretty good gas millage. But what if there was a way to totally eliminate friction so that cars could travel much farther on a single gallon of gas and would last much longer without costly maintenance.
To create a system with almost no friction the fundamental mechanics behind friction must be understood. On a large scale friction is caused by tiny ridges in the surface of one material grabbing on to ridges in the other. This has been known for a while but researchers have just found a way to understand what’s happening at an atomic level.
They created a surface of charged ions then shot a laser over the surface. The charge in the ions refracted the laser in ways that allowed the researchers to measure the forces involved in friction on an atom by atom basis. This system was only conceived a few years ago and it give researchers a powerful tool in the hunt for practically friction free surfaces.
A more technical and in depth discussion of this research can be found here: http://www.nature.com/news/friction-of-a-single-atom-measured-with-light-1.17698
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be Andrew’s last Open Mind post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
Last week, I had one of the best educational experiences of my life: a whole day of teaching 6th graders about STEM (Science, Technology, Engineering, and Math)! My lovely girlfriend is a 6th grade, Math and Science teacher and was constantly asked by her students as to when I would visit her class. With the build of DORY in full swing and wrapping up my undergraduate degree, I just couldn’t make time for a visit during the school year. In the last few months, my interest in teaching has grown, especially teaching about science, technology, and engineering. I knew I would take the opportunity to speak to her kiddos the first chance I could get.
My girlfriend and I made plans for me to visit the second to last day of their school year. Her kids and I couldn’t be more excited. I made a presentation about STEM and how it applies to our everyday lives. I appealed to their interests by highlighting: famous people and how they use technology, popular electronics and how they wouldn’t be around without STEM, and popular social apps and how they came to existence using STEM. I also showed them famous celebrity engineers such as Ashton Kutcher, Rowan Atkinson, and Michael Gambon. I then continued to show them projects I worked on in my undergrad such as an obstacle avoiding cart and DORY, as well as a live demonstration of a self-balancing wing. They had so many questions with some that showed real engineering intuition. Seeing the excitement in their eyes and the “light bulbs” turn on was a fulfilling moment for me.
At the end of my presentation, I gave them a little background on electrical motors and brought materials to help them make their first simple motor. With a couple of magnets, a battery, copper wire, and a bit of patience they all made a homopolar motor. One team even had their motor spin for 14 minutes before the wire fell off. We even had time to make paper bridges which turned into a very competitive activity!
Although the day was filled with laughter and excitement, it didn’t come easy! Often times we (meaning my girlfriend!) would have to correct the kids when they would get too roudy or speak out of turn. By the end of the day, we were both so exhausted. I have a new appreciation for middle school teachers and am glad I had the chance to try out the position. It is one difficult career! Teaching 11 year olds may not be in my future, but teaching STEM classes could definitely be!
Until next time…
Electric motors are used in many applications from robotics to children’s toys. Although many of these motors are DC motors, Homopolar motors are the simplest of motors and are easy to show students in a classroom setting. All it takes to build your first simple motor are three common materials you can probably find around the house: copper wire, a AA battery, and neodymium magnets.
Constructing the motor is simple but getting it to work can take trial and error as well as a bit of patience. Here’s how to do it:
1) Attach the magnet to the negative side of the battery.
2) Strip the copper wire completely or for safety, in the middle and at the two ends.
3) Bend the wire so that one end touches the positive terminal and the other end touches the magnet. A common approach is a heart shaped wire for better stability.
4) Watch: As the copper wire touches the magnet, the wire will begin to spin.
How does it work? Well the theory can get as detailed as you want it to be but to keeps things simple, I will explain the homopolar motor briefly. The copper wire connects the positive terminal to the magnet at the negative terminal. This completes the circuit, allowing current to flow through the circuit (and the wire). Due to the magnet, the current is flowing in the presence of a magnetic field around the battery. When current flows in a magnetic field, it will experience a force called the Lorentz force. This force acts perpendicular to the magnetic field and the flow of the current (and the wire). Consequently, the perpendicular force pushes the wire around the battery.
Once you get a working motor, you can change the shape of the wire to any shape you want! Have fun!
Until next time…
A big thank you to Mr. Russ Neff and the rest of the team over at Bandel Manufacturing for donating the materials and lending the tools necessary for us to shape the body of our underwater vehicle! A few pictures of the process of building the body to our design are included below:
Once again, we thank Bandel Manufacturing as we could not have created the body of our vehicle without you. For more on Bandel Manufacturing, please click this link to their website or visit our Sponsors & Donations page to find the link there.
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be Andrew’s last Well Read post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
The tiny toothed pincers above are part of a non-robotic system called the da Vinci Surgical System. The design is called non robotic as the operating doctor is in full control of the system. It basically translates the movements of a surgeon into micro-movements in the da Vinci’s intruments.
The idea behind this system is to give surgeons expanding capabilities and a minimally invasive option for major surgery. Here is a video of it in action:
Now that is some cool engineering!
Until next time…
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be my last Presentation post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
Today I’m going to be doing something a little bit different; I’m going to stick with the three-approach style of our Open Mind type posts, but rather than talking about the design/analysis/engineering/etc. behind real world science or technology, I’ll be demonstrating how engineering subject matter can be used to draw conclusions about life lessons. This is an important exercise for engineers, as many engineers and engineering students unfortunately become trapped within the framework laid out by their coursework with regards to their engineering mindset.
This is to say that many engineers only practice engineering and apply their knowledge within the confines of where/how they have been taught to apply it (i.e. in the design of a machine, or in the thermal analysis of a heat exchanger, or in the development of a control system for a robotic prosthetic arm, etc.). In reality, engineering curriculum can be applied in endless scenarios and the engineering mindset can be used in an infinite amount of situations outside of the world of engineering. Abraham demonstrated in a recent post how the engineering mindset can be used to solve everyday life problems (click here to read his post), but today we are going to talk about how the subject matter, specifically, can be used to teach life lessons by demonstrating this practice through three examples.
So without further ado, let’s get started!
Often times in life we find ourselves trying to do it all, and in doing so, stretching ourselves pretty thin. For a mechanical engineering student this might look a little bit like the following scenario: working full time, going to school for mechanical engineering, minoring in materials engineering, leading team projects for classes in materials science, heat transfer, and mechanical measurements, while on a senior project team that requires highly complex, innovative work in the subjects of materials science, mechanics of materials, fluid mechanics, heat transfer, control systems, dynamics, etc., while applying to grad school, while searching for and applying to internships, while working as a scientific/technical writer for a website, while trying to deal with car problems, issues at home, whatever it may be, things tend to stack up, and eventually it can become too much and something has to give.
Now picture if you had a circular plate-like piece of polyethylene (a polymer or “plastic”) and you attached a bunch of small clamps all the way around the circumference and started pulling with the same amount of force in all directions. Now we start increasing this force more and more…what happens? There is a phenomenon in the world of engineering called the Poisson Effect. The Poisson Effect basically tells us that as we stretch this material in this 2D plane (as shown in the picture), the material will compress in the direction orthogonal (or perpendicular to the plane)…so as we stretch the disk in all directions as shown above, the material will compress in the direction into/out of your computer screen. Now as we pull harder and harder on this disk from all of these directions, the disk will get thinner and thinner until it can no longer bear the applied loading and the material will fail. The material will likely fail near a stress riser, such as at the point where one of our clamps is pinching the material.
Flash back to the real world and we see that if we try to pull ourselves in a million directions with all of our effort, eventually something has to give. A better practice might be to prioritize our efforts and focus a little bit more in one direction than the rest. This might mean letting one of your teammates take over as team leader in one class so that you can focus more of your effort in another direction that may be more important. Perhaps the ideal situation would be to pull with all of your effort in one direction, I cannot comment on whether this is the right decision all of the time, as every situation is different. What I will say, is that you should keep in mind that from an engineering standpoint, if the plate was still to begin with and we pull equally on that plate in all directions, the plate cannot go anywhere, rather it will remain in the same position and eventually fail; however, if we focus more in one direction than the others, we can end up with a net force in one direction, and as follows from Newton’s 2nd Law, when we have a net force in one direction applied to a mass, that mass will accelerate in that direction…just something to keep in mind.
Even if we do figure out one direction to move towards, that doesn’t necessarily mean smooth sailing from there. Often times in life, we encounter distractions and obstructions to our goals. Some of these may be unavoidable, but we may be able to avoid others entirely. Perhaps when we see have a choice between being dragged down by obstacles that are avoidable and choosing the path of least resistance, we should choose the easier of the two paths. Now I am not saying that we should avoid all difficulty in life, no I’m not saying that at all, in fact, I am saying quite the opposite. It’s been said that nothing worth doing ever comes easily, and I agree with that sentiment entirely; however, there are obstacles that can be avoided so as not to distract you from focusing your effort on the unavoidable ones. These obstacles may be things like peer pressure or unhealthy habits that you know are not good for you and which will delay or maybe even prevent entirely your achieving your goals.
We can further justify this standpoint through an engineering analogy. As has been discussed many times on TeamUV.org (perhaps most recently in Andrew’s post on hydroelectric power), moving fluid can be used to generate electricity. In the picture above, we see an over-simplified diagram showing water flowing into turbines that will be used to generate electricity for power output. Now, essentially (from a very rudimentary point of view) what will happen is that the turbines will use the energy contained in the moving water to convert the water’s mechanical energy into electrical energy which can then be stored or used to power whatever we would like to power. Now let us consider the two cases shown in the picture above. In the first case, the water is flowing steadily down sloped terrain towards the turbines located downstream. This water will accelerate as it moves downstream due to the gravitational acceleration associated with change in elevation. As the water accelerates, it builds up momentum; this momentum can be seen as an increase in available energy in the fluid and once the water reaches the turbines, it will be this energy that is used to generate electricity.
Now let’s look at what happens in this second case, where the water is no longer flowing steadily in an unobstructed manner towards the turbines. The water is now running into obstacles left and right, and every time it does this, it loses a little bit of momentum. Look at it this way: the water accelerates downhill, building momentum, and then BAM!…it runs into a rock, forcing it to lose momentum and thus also lose some of that available energy. Where is that energy going? A large portion of it is being transferred to the obstacles themselves. This energy transfer may mean the rocks being pushed a little bit downstream, or perhaps even heated a small amount (although since there is water flowing over the surface of the rocks, providing efficient cooling convective heat transfer, the heating is negligible), or maybe this energy is being put towards erosion of the rocks…the point being, this energy is being transferred out of the moving fluid. By the time the fluid reaches the turbines, the available energy for doing work on the turbine blades to produce electricity has been greatly reduced. Comparing this to the first scenario, you can see how these flow obstructions can take up energy and reduce the amount of work able to be done in the end.
Moral of the story: if you are able to avoid destructive obstacles in life (as opposed to constructive ones that are necessary to get to where you want to be in life), you can avoid expending energy on trying to maneuver through these destructive obstacles, which would otherwise in the end reduce the amount and quality of the work you would have been able to produce by avoiding them altogether.
Lastly, I want to note that any obstacle, regardless of size, can be overcome if you are willing to work hard enough to do it. Take the subject of grain boundary diffusion for instance. Grain boundaries are exactly what they sound like; that is, they are boundaries between grains in a material (in this case we will think of a metal). These grain boundaries act as barriers to movement of dislocations and thus an increase in grain size results in an increase in yield strength…in simpler terms, the larger the grains in a material are, the more difficult it becomes to deform the material. What is the point of mentioning this all? The point is to underline the fact that grain boundaries serve as obstructions to movement of dislocations and atoms, just as difficulties in life lead to the impeding of forward progress. But all is not lost, atomic diffusion across grain boundaries is not impossible. With enough effort, diffusion across these grain boundaries can occur.
There is an activation energy that describes an energy threshold that must be overcome in order for diffusion across the grain boundaries to occur. This energy threshold can be breached by adding enough thermodynamic energy to start the diffusion process across the grain boundaries. In life, you may arrive at objects that seem impassible, but that is not the case. All you have to remember is that there is always a threshold, or activation energy so-to-speak, where if you can work hard enough to overcome that threshold, you can achieve your goals. It is not a matter of whether something is do-able, it is a matter of whether or not you are willing to work hard enough and put in enough energy to do it.
So there you have it, just three examples of the endless ways in which engineering subject matter can be used to each life lessons. Hopefully we all take something away from today’s post…whether its the importance of prioritizing, or the costs of letting destructive obstacles drag you down, or simply the age-old mantra of mind over matter, hopefully we all walk away a little bit more determined today, because life is what you make it and you will only get out of it what you put into it.
Enjoy the rest of your weekend and be sure to check back on Tuesday for Andrew’s last Well Read post!
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be my last Presentation post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
Tracking tags are used to gather data that concerning the behavior of whatever they are attached to. Often times you will see these tags attached to underwater creatures in order to gather large amounts of important information regarding the migratory patterns, mating behavior, predator-prey relationships, hunting/feeding grounds, social behavior, and feeding behavior of sea (as well as other) creatures, just to name a few parameters.
As you can probably imagine, from an electro-mechanical standpoint, these devices must be very well designed and quite technologically advanced in order to be able to gather all of this information through logging positions, orientations, accelerations, temperatures, video, perhaps audio, and so on and so on. On top of this, the power supply must be capable of lasting a very long time so as to enable the data to be collected continuously without a battery change; either that or the device must be able to recharge itself (i.e. solar recharging), which would of course mean gambling on how much time the creature spends near or on the ocean’s surface where the sun can recharge the device. The device must also be attachable in a way that will keep the device in place for a long time without irritating the creature. Vibrations must be controlled so as to not irritate the creature or skew the data and interfere with the sensors, thermal management must be sufficient to not only protect the on-board electronics, but also to not provide discomfort to the animal, the device must be able to withstand impacts and the wear & tear of daily routines, and the device must not interfere with the creature’s behavior in any way. Combine all this with the fact that the device must be waterproofed, often to great depths, without interfering with the sending and receiving of signals, and you begin to see the formation of a pretty hefty problem statement. And oh yeah, we can’t forget that at some point the researcher must be able to get the data (and hopefully the device) back! And lastly, according to your boss, the design must be complete and ready for prototyping by noon Friday and you have a $30 budget!
Theses kind of issues represent the same types of issues that mechanical (and other) engineers must deal with on every project they work on; as a matter of fact, the issues above share a great deal of similarity to many of the issues we had to design for in our underwater vehicle! (except that we had much, much more to design for since we were designing an entire vehicle, so we could rather equate the amount of issues above to those we had to design for for each of our 7+ subsystems!) This provides the background for an excellent conclusion and underlying theme in the world of engineering in general (and mechanical engineering in particular): You cannot design for everything.
Uh oh, does this mean that mechanical engineers are not putting enough work into their designs? That they are being negligent? No, of course not, this is just a simple fact. As much as we might want to think it, the reality is that no design is perfect. As we have demonstrated time and time again here on TeamUV.org, mechanical engineering covers what is essentially an infinite amount of topics, and thus mechanical engineering projects require an infinite amount of considerations. It is humanly impossible to design for everything, because the engineer cannot think of everything. So what do we do instead? We pour ourselves into our work and give the project 150% of our all and do everything we can to consider as many things as we can, and then…we accept the fact that we could not have possibly considered everything, come up with a contingency plan for when (not if) an unforeseen issue arises, and we go back to work.
So what does all of this have to do with tagging marine life? Am I just getting sidetracked? Nope, the reason I am choosing to talk about these things in this context is that this is exactly what has happened with these wildlife tracking tags. The engineers who created these tags did not spend enough time on one crucial detail that may have been seen as a relatively minor issue at the time, but which may have profound consequences regarding the validity of the data gathered and the well-being of the creatures themselves. What is this parameter that was not given enough attention? Drag.
As many of you are aware, drag is essentially resistance to movement through a fluid. Underwater creatures are often streamlined very well because nature is the ultimate engineer and underwater creatures have been optimized for their lifestyle through generations of natural selection. When you attach a bulky electromechanical device to a creature that has been streamlined for the optimal results in its environment, it can have a disturbing effect on the behavior of said creature. Go figure. In fact, as researchers at the National Oceanic and Atmospheric Administration Pacific Islands Fisheries Science Center in Hawaii have found that the disturbance to the fluid flow over the creature caused by the presence of these devices is resulting in increased drag anywhere in the range from 5-100% depending on turtle size and age. This in turn translates to slower speeds for the turtles, lower accelerations, decreased maneuverability, and possibly even behavioral changes due to some unforeseen psychological or emotional effects on the turtles. As a final segue, this in turn can lead to turtles behaving radically differently with regards to patterns, travels, social behavior, etc. that could mean receiving skewed or otherwise invalidated data, as well as a possible decrease in the turtles’ psychological and even physical well-being.
As seen in the video, in this fascinating study, these researchers are studying these disturbances are using some pretty innovative means to do it. The researchers are using the bodies of turtles that deceased from natural causes to form molds to create fiberglass sea turtle bodies of various sizes, which can then be analyzed in low-speed wind tunnels to identify and quantify the flow disturbances caused by these devices. This is an excellent example of one of the major job roles for scientists and engineers: analyzing an issue that was perhaps not considered, not understood, or possibly even simply not known at all to be an issue beforehand in order to gain a better understanding of the issue and then remedy the issue by developing more polished solutions.
One would only wonder why the tail fins were not taken into account in the model, as even though the disturbance is topside and the fins are located on the bottom of the body, with that large of a disturbance upstream, the flow about the tail fins would absolutely be effected in some way by flow separation and subsequent recirculation about the aft portion of the body. Oh well, moral of the story: it is impossible to account for everything, and sometimes it may even come down to cost-savings, ease of design, manufacture, or analysis, or even just simply deadlines. So what do we do? We put our best foot forward, give it our all, be prepared for the imminent issues down range, hope for the best, and to reiterate, we never give anything less than our all to a project for reasons of pride, protecting our reputation as engineers or scientists, and ultimately to do our best in the name of science and engineering.
Please come back Sunday for my last Open Mine post on TeamUV.org! For more info on the above research, click here.
As many of you are aware, we are in the transitioning phase of this website as we close out TeamUV.org and transition to EngineeringAFuture.com over the next two months, so this will be my last Well Read post here at Team UV, but not to fear, there are still two months of posts left here and the same types of articles will be carried over onto EAF (Engineering A Future), so without further ado, please enjoy the following:
Have you ever heard the expression that someone is “as blind as a bat”? Well this expression is not entirely accurate as no species of bats are actually blind; having said this, bats do have horrible eyesight, forcing them to rely on a different way to get around and navigate obstacles. More specifically, bats use SONAR (SOund Navigation And Ranging) in order to navigate the skies. SONAR is essentially exactly what it sounds like; that is, it consists of the use of sound waves to both navigate and to determine the range (distance) to something. As we have discussed before here on Team UV, SONAR consists of both passive and active SONAR, with the former being simply listening to the sound emitted from an object in the environment and the latter being the emitting of sound and then listening for the return echos. Well, as it turns out, bats are kings of both worlds because of the intricate design of their ears and noses.
As seen in the photos above, different species of bats have different configurations of ears in order to navigate the different types of environments that they inhabit, but there are some key features of the ears that are common across almost all bats: grooves, ridges, flaps, and other kinds of ear baffles. All of these features allow the bats to effectively filter out or attenuate some signals while selecting and encoding other signals to make them more easily understandable. All of this is accomplished by the refraction of the signals on the basis of how the sound waves physically interact with the geometry of the ear or by the resonance introduced within the ear due to how the various features of the ear affect the vibrations introduced by the sound wave-ear interaction. In essence these bats are able to reject or suppress all of the irrelevant information stored in the way of sound waves, while selectively highlighting all of the relevant information that they require to be able to acrobatically maneuver through their environment with ease. But wait, there’s more! Bats can actively adjust their ear configuration by deforming their ears in order to constantly change how they filter information and what information they filter. To take this a step further, bats can do this up to ten times per second, or about three times faster than a human can blink their eyes, allowing these bats to adapt at far less than a moment’s notice!
Everything discussed so far has focused on passive SONAR abilities, but bats also excel with active SONAR. Why is this the case? Because not only can they deform their ears, they can also deform their noseleaves (leaf-like flaps on their noses) to produce a highly focused SONAR beam and to alter the properties of that beam. This translates to the bats being capable of being selective both on the emitting and receiving ends, making them extremely efficient at utilizing their SONAR (not to mention the fact that bats are capable of using far fewer SONAR pulses/beams to navigate than man-made SONAR devices due to this increased efficiency). When you combine this with the fact that they manage to pack all of these biosonar capabilities into such a small package, it is no wonder engineers are studying them to come up with smaller, less power-hungry, more cost-effective, and more efficient SONAR.
To sum up the merits of adapting this biosonar for man-made devices, I will quote Rolf Mueller, the mechanical engineer behind this research:
“The split-second decisions that bats on the wing have to make will often be based only on a very small number of echoes. Based on these few input signals, the bat’s brain is able to make the quick and reliable decisions that swift flight in confined spaces requires,”
You can find more info on this research here: Bat’s biosonar inspires sensing technology research
So there you have it, just another example of how biomimicry or biomimetics is helping to greatly advance the state of science and technology. Please come back Thursday for my last Presentation post on TeamUV.org!
Team UV was selected to represent the Mechanical Engineering department here at Cal Poly Pomona during Friday’s Engineering Project Showcase, where we presented a very brief (12 min. presentation) introductory look at some of our research to the other presenters, faculty from all of the engineering departments, and some industry representatives. We took 3rd place overall and walked away with a certificate and significant cash prize, bringing this chapter of Team UV to rest.
This was our last planned presentation, although we are considering some journal submissions, possible conferences, competitions, and the like further down the road; however, for the time being, we will be closing the book on Team UV. Over the next 2 months, we will be saying our goodbyes on TeamUV.org through some send-off posting. Not to worry, however, because the same style of posting will be carried over onto my website (EngineeringAFuture.com) with many of the same authors upon closure of TeamUV.org. I created EngineeringAFuture.com back in December 2012, but never got it off the ground…flash forward to 2 years later and TeamUV.org launched in July 2014 with the same goal of inspiring interest in the STEM (Science, Technology, Engineering, and Mathematics) fields, but with the added goal of sharing some of the progress of our project. Engineering A Future is an active domain, so you can check it out now if you would like, but everything you see on there currently will be changing as the website is retrofitted over the next 2 months in preparation for its relaunch.
In closing, while I believe that I speak for all of Team UV when I say that we will greatly miss writing for our readers here at TeamUV.org, this should not be looked at as the end, but rather simply a new chapter in our book as we transition to EAF (Engineering A Future). In the next few weeks, posts will occur as follows:
Full Week of Posts with Regular Scheduling (Well Read Tu 1000, Presentation Th 1000, Open Mind Su 1300)
Brian: June 2, 4, 7
Andrew: June 9, 11, 14
Ben: June 16, 18, 21
Abraham: June 23, 25, 28
Ketton: June 30; July 2, 5
Goodbye Posts (M, Tu, W, Th, F 1000)
Andrew: July 6
Ben: July 7
Abraham: July 8
Ketton: July 9
Brian: July 10
This means that July 10, 2015 1000 hours will mark the last post for TeamUV.org. Posting on EngineeringAFuture.com will begin the following week; I will announce the post scheduling for EAF on July 10 as a few things are still yet to be set, but it will be either 2 or 3 posts a week.
Thank you to all of our readers for all of your time and support and I look forward to continuing to write for you all over at EAF, but for now, please continue reading here at Team UV as our regular scheduling continues with my full week of posts starting on Tuesday.
Thank you for your time
We’ve all been taught that water freezes at 32F (0C) but in actuality water can remain liquid below this temperature, under special conditions. Imagine you’re sitting on your couch after a long day, you’re tired and you’re starting to feel a bit hungry, but the fridge is so far away. Eventually you get hungry enough to get up, go to the fridge, and satisfy your hunger. Water can relate. When the temperature of the water drops below 32F it would prefer to be a solid, but it takes energy to change from a liquid to a solid. As the temperature gets lower the water gets “hungrier”, it wants to be a solid even more, eventually it wants to be a solid enough to overcome the energy barrier, the “walk to the fridge”.
When water wants to become a solid there are two ways it can go. It can either grow on a surface, like condensation on a cool drink or around a dust particle like rain, or, if it has enough energy, it can grow little spheres of solid within the liquid, without the help of a surface. The amount of energy required for this phase transformation is directly related to the amount of surface created. When the transformation is happening on, say the inside surface of a water bottle, the liquid only has to support the area of a dome, the bottle takes care of the rest. When there is no bottle to work with, or the liquid is far from the surface of the bottle, it has to have enough energy to support the surface area of a whole sphere.
If you’re trying to replicate the video above it’s crucial to have very clean water. This means there are no little particles that the water can use to lower the amount of energy required to freeze, it has to save up enough to grow the spheres without any help. The water also needs to be cooled slowly and handled gently because any significant energy changes, thermal or kinetic, can give the water enough energy to start freezing. This is why hitting the bottle will start the reaction. When the bottle is hit, it finally gets the “oomph” it needs to get to the fridge (freeze).
These phenomena (heterogeneous and homogenous nucleation) are also responsible for the famous Mentos and Coke experiment, why bubbles in carbonated drinks seem to come from specific points in the glass, and how engineers make aircraft aluminum strong enough to keep planes in the sky.
Imagine it’s Valentine’s Day again and this year you want to take your significant other somewhere special but you don’t want to drive for hours is congested traffic just to get there. Enter Joby Aviation with their S2 and S4 personal air transportation vehicles. Joby CEO and founder JoeBen Bevirt has been working and developing the S2 two-seat electric aircraft for the last 10 years.
The S2 uses twelve different propellers and sensors which allow it to perform vertical take off and landings. The S2 can achieve speeds of up to 200 miles per hour and has a battery life of one hour. So in ideal conditions, the S2 can travel up to 200 miles on a single battery charge which puts it in the weekend-getaway or even the commuter vehicle range. Currently the S2 and S4 are piloted crafts but essentially the goal of Joby Aviation is to create drones for people for short haul air travel, however, there are many obstacles to this goal.
First and foremost is the legal aspect. Drones are not looked upon well yet in the light of the law. The Federal Aviation Administration is currently reluctant to allow trials for drones to deliver packages like with Amazon’s Prime service. There is no chance that they will allow for super-drones to deliver people. New legislature needed to grow almost ahead of the technology and because it did not, the legal issues will take an estimated seven to ten years to resolve.
Technologically speaking there are some hurdles as well. Bevirt wants to build a quiet, safe, and efficient aircraft that will get you to your destination five times faster than just ground transportation. However, if the aircraft is too loud, then the product is dead before it hits the market. Bevirt has a goal to make his aircraft 100 times quieter than a helicopter putting it roughly at 65 decibels at 240 feet altitude.
There are also infrastructure issues as this technology will make use of heliports for landing and taking off. Even big cities like San Fransisco only have six in the entire city which makes it unlikely to be a commuter mode of transportation at least for now. Bevirt quotes the S2 price tag at $200k which is comparable to, yet is much cheaper than the Robinson R22 helicopter. The dream is big and that’s what we’re all about here at TeamUV. For more information here is the technical paper to the S2 aircraft: http://www.jobyaviation.com/S2ConceptualDesign(AIAA).pdf
The underwater world is beautiful and mysterious and as it makes up most of the livable volume on this planet it’s natural that humans would be interested in exploring it. SCUBA diving is one of the easiest and most accessible ways to explore the world under the waves. Getting humans to stay alive and comfortable for any length of time requires some pretty intense engineering.
The big problem is that humans need air. So SCUBA divers carry on their backs tanks of compressed air that they breathe for the length of the dive. The more air a diver can bring with them the longer they can stay under. The divers could either take larger tanks or try and pack more air into the tanks they already have. Really large tanks are impractically heavy and expensive so that option is out. That leaves packing more air into the tank, as more air is added the pressure increases because, for standard conditions, air follows the ideal gas law, PV=mRT. Where “V” is the volume of the tank, so that’s going to stay the same, R is the gas constant, T is the temperature which will stay constant as long as it’s filled slowly. This leaves P, the pressure of the tank. Modern SCUBA tanks are filled up to 3000 psi. That’s 3000 pounds of force on every square inch of the inside surface of the tank, or a large elephant standing on every 2″x2″ square of interior surface area. It takes some serious engineering to handle that without exploding.
Keeping an open mind, and being aware of the engineering that goes into many of the things that allow humans to explore where they could never go before, from the ocean to outer space is important. Advances in materials, mathematics, computers, and physics keep pushing the boundaries so that things once thought impossible become commonplace. Keep an open mind and keep learning, the future is going to be unimaginably incredible!
Of all the bird species of the world, the hummingbird has some of the most unique and impressive abilities. It has the highest metabolism of any warm blooded mammal on the planet, it is extremely light, and it flaps its wings so fast that the frequency can even be picked up by the human ear. Some of the fastest flapping hummingbirds can generate up to 200 flaps per second! And not only this but they are able to hover in place, fly backwards, and even shake off water from their bodies all in midflight! Many scientists have researched the hummingbird and have learned that it does not flap its wings in the traditional up and down movement but instead in a back and forth movement creating lift in both the up and down stroke. About 70% of the total lift is created in the down stroke and 30% in the up stroke in one cycle of flapping. Even in wind tunnels these feathered fiends are able to withstand winds of 20 mph by using their natural aerodynamic, streamlined body and tail as a rudder to maneuver through the passing air. Obviously here at Team UV we are interested in harnessing the power of nature through biomimicry and scientist and engineers are doing the same with the hummingbird. Tiny helicopters attempt to recreate the hummingbird hover but currently are not as good as the real deal. More on the mini-helicopter-drones http://www.futurity.org/hummingbirds-micro-helicopters-740052/.
The device shown above is smaller than your finger and it might be the future of devices to treat a fractured spine, pinched nerve, or neurological disorder like epilepsy. Oh…did I mention that it was implantable!?
A team of engineers and medical researchers in Sweden has just designed a pinpoint-accurate implantable drug pump. It delivers medicine with such precision that it requires only 1 percent of the drugs doctors would otherwise need to deploy. As it demonstrated in tests on seven rats, the tiny pump can attach directly to the spine (at the root of a nerve) and inject its medicine molecule by molecule.
The technology is based on a compact but complicated piece of laboratory equipment called an ion pump. To put it simply, as electric current enters the ion pump one electron at a time, medicine is flung out the other end one molecule at a time. One caveat: Because of this setup, only medicines that can be electrically charged can be used with the pump. But that includes more pain medicines than you might think, including morphine and other opiates. In their study, Jonsson and her colleagues experimented with gamma-aminobutyric acid (GABA). This chemical essentially puts the brakes on nerves, reducing pain, but it stops being produced where the nerves are broken. Jonsson’s approach was to use her new drug pump to simply put more GABA back into the broken part of the spine.
With any other drug pump this would be ineffective if not insane—the GABA would simply travel throughout the spine at leisure, wreaking widespread havoc and disrupting the nervous system. But, with the ion pump’s pinpoint precision, Jonsson could inject incredibly small amount of GABA right where they needed it, without the risk of major damage. And it worked. When the scientists gave the test rats a common pain-response test (essentially poking their paws, and seeing how much force was needed for them to retract their arms) the rats with drug-pumps could on average withstand 5 times more force.
Jonsson is emphatic that her medical device is still in the research phase, and a real ion drug pump may be years away. Scaling up the pump to the size required for human needs might not be too big of an issue, but for this experiment, the researchers had their rats implanted with the pumps for three days only. The shell of the pump would likely need to be changed for longer-term use, she says. Regardless, drug pumps like Jonsson’s may hold the promise of future biomedical devices designed to assuage nerve pain and treat neurological diseases.
“Things present themselves to you, and it’s how you choose to deal with them that reveals who you are. We all say a lot of things, don’t we, about who we are and how we think. But in the end it’s your actions, how you respond to circumstance that reveals your character.” – Cate Blachett
Problems are simply a part of life and are statistically unavoidable. However, just because everyone has problems does not mean we all approach them in the same way. It is your individual mindset that determines this. Two people can look at the same problem and have polar opposite outlooks. Personally, years in the higher education system have given me an engineering mindset which contains problem solving skills which I believe are the most valuable tools at my disposal because they can be applied to almost any problem in engineering and in life. To solve almost any problem you need to take the time to identify what you’re given, what you’re trying to find, and what are the steps to your solution. Easy right?
This is only the tip of the iceberg in terms of how the engineering mindset can solve almost any problem. It is truly a universal tool that can be applied almost anywhere. As a young man about to enter the ‘real’ world in just a few months, I can confidently say I am ready for anything thanks to the mindset I have acquired.
Good morning, I will be filling in for Ketton’s normal timeslot today due to a last minute complication, so this post will be pretty short.
Fluid mechanics does a lot for us as engineers and scientists with regards to everything from furthering our understanding of planetary atmospheres, to helping us to figure out how to supply an entire country with flowing water, to allowing us to analyze the aerodynamics of some of the most complex vehicles the world has ever seen, the reach of fluid mechanics extends far beyond that of the science, technology, engineering, and mathematics (STEM) fields. One are in which fluid mechanics is finding more and more application is in art.
Now, the form of fluid mechanics seen in art is a little bit different in that we are not talking about the high-order, nonlinear, partial differential equations or the highly complex scientific theory behind the flow of fluids, but rather simply the beauty associated with all that flows. The video (A Love Like Pi ‘Jack and the Giant’ by Kim Pimmel) at the top of the post is an excellent example of this and shows how fluid mechanics can be quite mesmerizing. As stated by Nicole Sharp over at FYFD (please excuse the name of this website) shares, this video essentially uses the interactions between diffusion, buoyancy, Marangoni Flow, ferrofluidics, and other fluid dynamic phenomena to create something pretty awesome. This kind of interaction between many different highly complex fluid dynamic effects within a seeming simple phenomenon is very much so characteristic of the world of fluid mechanics; and while it may take years of education and training in the field of fluid mechanics to even begin to truly understand and be able to analyze these flows on an engineering and/or scientific level, part of the beauty of fluid mechanics is that anyone, regardless of education or background, can enjoy it.
To close off this post, I have included a few more pictures of flows within the context of art with lists of some of the phenomena at play/fluids keywords in each of them. Enjoy!
Note: All images below found through FYFD.
Trying to hit a moving, accelerating, and evasive target at long range? No problem, America’s Defense Advanced Research Projects Agency (DARPA) has you covered. That’s right…a project named Extreme Accuracy Tasked Ordnance (EXACTO) now allows the military to hit targets that move and evade with high accuracy. The video below shows an experienced marksman using the remarkable technology along with a novice shooter completing the same task.
The EXACTO program is understandably secretive about the technology but we know that they have stuffed a “real-time optical guidance system” into a .50 caliber size round. The system accounts for the rough terrain, environments (weather, wind, etc), and other factors soldiers are exposed to that can hinder successful hits. Future work can now be done on other caliber rounds and other applications.
More information here!
Until next time…
Stanford engineers are getting ready to reveal their new tiny robot that perhaps should have the name Superman as it is extremely strong. The reveal is taking place at the International Conference on Robotics and Automation which is held in Seattle. The small robot can not only carry many times its own weight, it can do this while climbing up a wall.
This is the smallest robot to have been created at Stanford. One of their robots is able to carry 500 milligrams while its own body weight is just 20 milligrams. It may only be carrying a paperclip but bear in mind that the robot itself is so tiny that it had to be assembled underneath a microscope. UTug is the even more powerful as it can drag weights of up to 2,000 times heavier than its own body weight. It weighs just 12 grams (~0.03 lb) and can carry around 24 kilograms (~52.9 lb). This is the equivalent to a human being walking around dragging a blue whale behind them.
The incredible strength of the robots is due to powerful motors and superb traction. The engineers working on the robots gave them feet that take inspiration from that of a gecko. The feet have an adhesive surface which has tiny rubber spikes that allow the robot to stick to the surface. If downward pressure is applied, the spikes are able to bend, this gives them increased surface area and therefore high adhesion. As soon as the robot lifts its foot the spikes straighten out. The locomotion of the robot means that it moves slow and one foot has to stay planted to anchor the weight of the robot. The designers behind the robot believe that the robot will come in handy in construction to carry items that are heavy and which need to be hauled around.
A while back, I wrote a brief article on the pros and cons of alternative energy where I covered various forms from solar to wind. In this article, I will be covering my favorite form of power production: Hydropower! After quickly visiting the Hoover Dam in Nevada, the Washington Water Power Station in Spokane, and taking a tour of the McNary Dam in Oregon, my interest in generating electricity from moving water was rekindled. Many people flock to these large facilities for their grand views and powerful waters but may not know about the actual power production method.
Hydroelectric plants produce power in a very similar way to other common methods such as coal-fired power plants. Regardless of power source, rotation of a turbine turns a generators shaft producing electricity for us to use. Instead of using steam to turn a vapor turbine, hydroelectric plants uses the energy from flowing or falling water to turn a turbine.
The root idea is to find a location with a large watershed area (where a lot of rain and snow falls). This also happens to be where rivers flow. If a lot of reliable water falls in an area, a lot of reliable energy can be produced. Another consideration for finding the most ideal place for a plant is river elevation drop. This gives power designers usable “head” or pressure created by the difference in elevation. After a location is found, designers will have to match the power produced by the plant with the power consumed by the consumers (me and you). Once they have the load demand for a typical day, they can calculate the flow needed to the turbines to meet that demand. Having numbers for head and flow are the two most important factors for designing a hydropower plant.
Next, a dam, or structure to hold back water, helps to create a volume of water that will be fed to the power stations turbines. The dam has to be designed to create a sufficient reservoir with low risk of emptying. Low head or an empty reservoir means no electricity to match the needs of the consumer.
Once a dam has been built and water has filled the reservoir behind it (which can take some time), a power plant can produce electricity. An intake brings water through a penstock (a large supply pipe) to the turbines. The best part of hydropower is that it incorporates the most efficient conversion of energy: work to work. Flowing water turns a turbine which rotates a generators shaft. This produces electricity that is sent out to an electrical grid. The water’s energy has been converted and is sent away through a draft tube to continue on the rivers course.
Electricity from the generator isn’t automatically ready to be used. It is often times upwards of 400V and needs to be stepped up to travel long distances. A transformer steps up the electricity to upwards of 110kV (110,000V) to limit the amount of losses incurred traveling thousands of miles to consumers. When the electricity reaches its consumers, it is then stepped down to safe usable levels such as 110V to 120V for home use.
As you can see, there is a lot of engineering behind hydropower plants and I hope I have given you all a bit of insight as to how they work. There are a ton of dams across the U.S but not many in Kansas or Florida for their relatively flat terrain. In fact, there are 80,000 unpowered dams in the United States which could provide gigawatts (billions of watts!) of electricity. There are many different forms of hydropower plants in existence with the described one above being a single style. There are run of the river dams too which don’t have any reservoir and rely on the high flow of the river more than the head of a dam.
For more information on hydropower or other forms of alternative energy, visit energy.gov
Until next time…
Although ‘Dead Water’ may sound like the title of a movie that will make you steer clear from swimming in the ocean for a year, it is actually the name for an interesting fluid-dynamic phenomena experienced by nautical vessels (and, as it turns out, a detective novel by Ngaio Marsh). Right then…back on track.
Dead Water describes an effect wherein a vessel (i.e. a ship) that is moving by way of thrust produced below the water line (i.e. a propeller) begins to slow, sometimes even to a complete stall due to a mysterious force that seems to be dragging the vessel backwards. How does this happen? Well, there are things called internal waves; essentially, these are waves that appear much as the usual surface waves that you might think about when you picture ships at sea, but that exist below the surface at the interface of fluids existing at different densities. It is important to note, however, that an argument can easily be made to refer to internal waves as a type of mechanical (as opposed to electromagnetic or seismic) surface waves, as surface waves are waves that exist at an interface between differing media…just like internal waves, the usual distinction being that surface waves are generally referred to as those at an interface between a liquid and gas (i.e. the ocean’s surface and the air above the surface), while internal waves would be between a liquid and a liquid.
You may recall doing an experiment growing up where you took water (dyed blue or red, etc.) and put it in a 2L bottle with some sort of cooking oil; because the two fluids were of different densities, they did not readily mix, but rather remained stratified. If you slowly rocked the bottle side to side (to avoid mixing the fluids), you created an internal wave! This is the kind of wave we are talking about right here, but rather than being produced by your hand moving a bottle, it is being produced by a ship’s propeller beneath the water.
In essence, the ship’s propeller is inserting energy into the fluid (the ocean), and this energy is being used to create an internal wave at the internal interface. As the ship continues to input energy into the fluid, the wave grows in amplitude, until eventually (much like waves at the beach), the wave breaks. When the wave breaks, it crashes against the boat; the reason you do not see direct contact between boat and wave in the above video is that the boundary layer between the boat’s hull and the far removed water is keeping them separated, but (rest assured) the energy of the breaking wave is transmitted through the boundary layer into the boat’s hull. This wave breaking creates local turbulence around the propeller, which further draws energy from the boat’s thrust (in addition to the thrust energy still being taken up by the waves forming down the line). The next part is a simple logical progression: if a boat uses a propeller to introduce energy into a fluid to produce thrust, then if an external force (i.e. internal waves) is taking up energy from the propeller, then it is also taking up energy from the production of thrust, then this translates to the boat not producing as much thrust as before and thus slowing down, perhaps even to a standstill (if the boat no longer has enough thrust to defeat the drag forces).
With the ship slowing down and possibly even stopping, even though its propeller(s) is(are) rotating at a constant speed, it is understandable how nautical travellers might have coined the term ‘Dead Water’ for something that they likely first perceived as being due to some crazy, mysterious sea monster that wouldn’t let them go, making them dead in the water…get it?
One last word on this topic…why is there these fluid interfaces in the ocean to begin with? Well, this stratification in ocean waters is caused by many factors, but mainly the difference in temperature, salinity (salt content), and thus density. For this reason, nautical goers are more likely to encounter Dead Water in regions with large salt inlets or largely varying water temperatures, such as near sources of inland fresh-water runoff into the ocean, or near glaciers.
With only a couple of oral presentations and other tasks left to do, our project is nearing its end (don’t worry, posts will continue on another website but more on that at a later date!!!). My time as a technical writer so far has been educational, inspiring, and fulfilling. Not many people know this, but before I considered a career in mechanical engineering, I was laying the foundation to be a journalist. I was heavily involved in my middle school and high school newspaper programs and even earned an award for my work. You can even find me in at least three Cal Poly Pomona Poly Post issues!
When Team UV decided to create a website where we could inspire interest in the areas of Science, Technology, Engineering, and Mathematics (STEM) I couldn’t help but feel that same passion. Writing for a STEM related blog takes planning and plenty of consideration for various demographics that may visit our site. We have to balance the use of heavy scientific and technical jargon with the ease of describing complex scientific and technical topics. Shifting to one side or the other could easily “cut out” a group of readers if we are not careful. Take the presentations on flow characteristics or materials for example, our team could easily approach the topics in a text book fashion but those without the prerequisite knowledge of physics and engineering will become lost. If we approach it too simply, we dilute the experience of understanding exciting scientific phenomena and may even belittle the many years of work gone into such topics.
The greatest moment of my technical blogging experience is when we met a TeamUV.org visitor at the National Conference on Undergraduate Research this past April in Washington. I still remember the look on his face when we brought up our website during the presentation and the excitement in his voice when he approached us afterwards. Meeting just that one person made the whole experience of driving over 3,000 miles and through blinding dust storms worth it.
I will continue to find opportunities to blog long after this project is over and I was surprised to find many exciting career paths in technical writing. It only makes sense that scientific websites and magazines have engineers on staff to write about various technical fields. Who else would make a better candidate to write a machine’s user manual?
Please continue to share our website and look out for a post about its future soon!
Until next time…
On Wednesday April 22nd, 2015 the Calbuco volcano in southern Chile erupted for the first time in 40 years, triggering the evacuation of 4,000 people in a 20km (~12.43mi) radius while disrupting air traffic over Chile, Argentina, and Uruguay. The eruption went on for an hour and a half and resulted in a plume of volcanic ash reaching 10km (~6.21mi) upwards.
At Team UV, our best wishes go out to those affected by this disaster and we are going to use today’s post to explore the science behind volcanic eruptions, in the hope of promoting a deeper understanding among our readers as to why and how these eruptions occur.
First off, we will be skipping over the science regarding the initial formation of volcanoes (plate tectonics, subduction, convection cells, etc.) in order to facilitate a more concise post/article; we will purely be looking at the eruption itself. So where do we begin? The answer is deep within the Earth’s mantle, far below the surface of the volcano.
The magma that exists deep in the upper mantle is under an enormous amount of pressure, and this pressure keeps the gases contained within the magma [i.e. water vapor (steam), carbon dioxide, sulfur dioxide, hydrogen sulfide, hydrogen chloride, and some additional strong acids] completely dissolved within the magma, meaning the gas molecules are distributed throughout the magma and are essentially embedded within the magma, much like the CO2 bubbles that are dissolved in your soda, that give it its carbonation, and which you do not see until after you have opened your soda, relieving the pressure within the container. Why is this the case that these gases are dissolved within the magma? Because the vapor pressure of the gases (the pressure exerted by molecules that escape from a liquid to form a separate vapor phase above the liquid surface; think of this as the pressure at which the molecules boil or evaporate out of the liquid) is lower than the surrounding confining pressure (the pressure exerted on the gases by the surrounding magma and rock, which is highly pressurized).
Okay, so we have now discussed the starting point, but what happens next? The next thing to occur will be a disruption in the balance between confining and vapor pressure. As the magma rises, it decreases in depth from the surface of the volcano, which means that it has less and less material stacked on top of it, which translates to a decrease in the confining pressure (the same way water hydrostatic pressure decreases with decreasing depth in the ocean). As the confining pressure decreases, eventually the confining pressure will drop below the vapor pressure, allowing the dissolved gases to begin to exsolve (emerge out from their dissolved state within the magma) and nucleate/form gas bubbles, or vesciles within the magma (just like when you relieve the pressure in your soda by opening the container, at which point the CO2 bubbles emerge). As this gas forms and expands, it effectively decreases the density of the gas-magma mixture, because for the same amount of weight as before, the gas-magma mixture takes up more volume than the magma-dissolved gas mixture of before, and density is defined as mass divided by volume. Since this new magma-gas mixture has a lower density than the magma-dissolved gas mixture, it floats (so to speak) to the top, allowing the bubbles to grow more and more as the magma rises further and experiences lower and lower confining pressures. In this way, the hot magma-gas mixture begins to rise faster and faster, accelerating as it moves upward.
Side Note: It is important to at least note that there are many causes for the magma to begin to rise in the first place (i.e. convection currents, insertion of new magma to pressurize the chamber further, etc.) and many considerations such as the increase in vapor pressure due to gas-content enrichment with crystallization of cooling magma, that we are not discussing here as they are not vital understanding the key fundamentals in a concise manner.
When the magma, which is moving quite quickly now, reaches the surface cap of the volcano, it can break on through if the cap is not strong enough. This cap strength is, in part, a reason why volcanoes do not erupt repeatedly day after day (in most cases), as once a volcano erupts, the magma becomes lava, which can solidify the cap once again, potentially trapping the magma and gases for another few decades until the cap has been worn away it and the volcano is ready to burst again. Having said this, a high cap strength can also produce a much more violent eruption, as the amount and pressure of the gases contained in the volcano will be much higher prior to eruption if they have been held back by a strong cap, without any side vents.
So, assuming the cap breaks, and the magma and its gases burst forth and produce lava, and ash (mostly frozen bits of gas and lava due to the transition from inner-volcano temperatures and pressures to the much lower atmospheric temperature and pressure), what decides the type of eruption? This comes down to viscosity. Now, you have probably heard the word viscosity before; this describes the resistance to shear strain/deformation in a material (usually liquid) resulting from an applied shear stress. Viscosity is often described as (although, somewhat improperly) as the molecular thickness of a fluid/plasma; so syrup is highly viscous, while water is much less viscous. The viscosity of the magma is largely determined by the percentage of silica in the mixture, and this viscosity has a direct effect on the type of eruption.
A high percentage of silica translates to a high viscosity for the magma; if the magma is very viscous, it is harder for the gases to escape out from the magma. In this case, when the volcano does erupt, the gases explode out of the magma with violent force, blowing bits of ash, rock and jets of lava into the air.
If the magma contains less silica and is more basaltic (containing more basaltic crust, which is essentially that found in the Earth’s crust beneath the ocean, which has a lower silica content), the lava will ooze out, as the gases are not strongly trapped in the magma. This is to say, the gases may freely exit from the magma, which is one reason why these eruptions tend to be much less violent, tend to ooze rather than burst, and tend to bubble more.
Side Note: In case you weren’t sure, the distinction between magma and lava is just essentially that lava is magma that is now external to the volcano.
So now that we’ve discussed volcanic eruptions, let us just take a quick second to figure out what’s going on with all the lightning shown in the first photo of this post; this lightning is termed volcanic lightning. There are multiple theories as to why this occurs, but almost all of them accept the following: as material is ejected out of the volcano, it breaks apart, either due to the explosive power of the eruption or due to collisions, as the material breaks into pieces, it is thought that differences in the aerodynamics of the positively charged vs. the negatively charged particles causes the two, differently charged particles to separate from each other. At this point, mother nature does what she usually does when there is a region of negatively charged particles separated from a region of positively charged particles: she bridges the gap by normalizing the charge imbalance with an electrostatic discharge…lightning. This seems to add another dimension of stunningly intimidating violence to the already destructive eruption.
Hopefully this post has helped to build the foundation for a deeper intellectual understanding of the process of a volcanic eruption. It is unfortunate that these eruptions tend to devastate regions all to often. The understanding of these powerful volcanoes is the domain of oceanography; and to this end, oceanologists, geologists, and volcanologists are constantly working to deepen their understandings of these acts of nature in order to improve forecasting and possibly prediction techniques.
3D Printing is coming up in the news and research more and more these days. But that just goes to show the versatility of this additive manufacturing technique. The majority of manufacturing up to this point has focused on taking a block of material and removing the parts of it that do not belong, like Michelangelo sculpting the David. New techniques based on adding material have opened a new venue for the creation of products and allowed engineers and scientists to create designs that would have previously been limited by old manufacturing techniques.
One of the cool new applications of the 3D printer idea is for organ creation. Scientists at Princeton University and John Hopkins University have created a 3D printer that can print a human ear. The device first creates a scaffold, something for cells to grow on and maintain shape, out of hydro gel, then it adds cells that will grow and form cartilage that will be the final structure of the ear. Read more about it here.
A chordophone is defined as any musical instrument that uses vibrating strings or strings connected between two points to produce sound, so you can think of things such as harps, violins, and even guitars as falling into this category. The first chordophone that resembled the classical acoustic guitar is said to have appeared about 3,300 years ago in a Babylonian stone carving, with a stark contrast to today’s modern acoustic, electric, and acoustic electric guitars, which have become highly optimized feats of engineering. Today we are going to talk about just a few of the many, vast engineering subjects applicable to the design of the modern guitar that have helped to revolutionize the way we play music today, regardless of what genre it may fall into…Blues, Indie, Latin Funk, Country, Hair Metal, Ska, Garage Punk, even some Hip Hop, and countless other genres and subgenres!
As Keysight Technologies points out in an editorial on the guitar as an example of engineering, “The guitar touches on a rich set of engineering principles, among them: resonant frequency, period, amplitude, distortion, harmonics, wavelength, stress & strain, elastic limit, am, fm, damping coefficient, Doppler effect, step response, coupled oscillations, fft’s and signal processing”. I can assure, this is in no way a complete list as in any engineering project, an engineer generally applies every subject they’ve ever learned about in some way, shape, or form, regardless of whether they realize it or not. Today we are going to pick three of the subjects most prevalent to an understanding of the mechanics of a modern acoustic electric guitar (an acoustic guitar fitted with equipment to increase the volume, so that one can play with the volume of an electric guitar, while still maintaining the sound of an acoustic guitar), and we will utilize a logical progression to do so, meaning we will move from the user’s hand, through the strings, through the body, back out to the atmosphere.
Strings & Frets
When a guitarist plays the guitar, they use both hands actively; generally this consists of strumming or plucking the strings of the guitar with one hand and using the other hand to push the string down at the frets (those raised, generally metal, bars that are transverse to the neck of the guitar) on the fretboard/fingerboard. When the string is disturbed (plucked or strummed), it vibrates, as it is connected rigidly at two ends, or nodes, (one at the saddle of the bridge, and the other end at the nut of the head). This vibration occurs at a resonant frequency that is a function of the string material (due to differences in density), tension, length, and diameter. This is to say that if you were to strum the top string of the guitar soft, medium, hard, whatever, it will produce the same frequency every time (unless the string contacts something, or you pluck it too hard and plastically deform, or stretch in this case, the string or pull the string partially out of the bridge or tuning keys, changing the length and thus frequency). If you want to hear a different frequency, you can move to a smaller (diameter) string for a higher frequency, play a guitar with a longer neck (and thus longer strings) for a lower frequency, increase the tension in the strings for a higher frequency, or change to denser/heavier strings to reduce the frequency (& vice versa for all of these; also note that change in pitch will positively correlate with change in frequency…i.e. lower frequency will produce lower pitch sound).
Now, what happens when we start using our other hand to press down the string at frets? Rather than having the string vibrate between nodes at the saddle and nut, it will be vibrating at nodes between the saddle and fret, changing the length of the vibrating portion of the string altogether! Following from this, a fret closer to the saddle (as opposed to closer to the nut) would produce a shorter string length, and thus a higher frequency or pitch! Now, if we repeat this action, but this time we do not push the string all the way down, so as to not lock the free side of the string from vibrating, we produce a harmonic. In essence, the vibration mode is changed as we create our frequency between the fret (or our finger in this case) and the saddle, and let it propagate down the string, adding to the frequency with each harmonic. In the far right picture below, we see the original first harmonic to the right of the finger, followed by the 2nd, 3rd, and 4th harmonics down the line to the left. If the first harmonic was vibrating at a frequency of 100 Hz, then the 2nd would be at 200 Hz, the 3rd at 300 Hz, and the 4th at 400 Hz. A musician (rather than an engineer) would term the 2nd, 3rd, and 4th harmonics the 1st, 2nd, and 3rd overtones.
Now that we have produced the vibration, it must travel through the body before we can hear the sound it produces. This action begins at the bridge, where the vibration of the strings is transmitted through the saddle (and followingly, the bridge) to the soundboard (the top plate of the guitar body, to which the bridge is attached). This soundboard is lightweight and has a large amount of surface area associated with it, which is important, because now that the soundboard is vibrating, we want to be able to transmit that vibration to the air inside the body as efficiently as possible. Lightweight materials that are relatively strong, yet also are fairly springy (to use a non-technical/scientific term) are very good at transmitting these frequencies with little loss/damping through the material itself; therefore, materials such as Spruce and Cedar (both are types of wood, if that wasn’t clear here) are used. If we were talking about solid-body or semi-solid electric guitars, here would be a good place to comment on the choice of center-body material, as the vibration would have to be transmitted through significantly more material before getting to the devices that convert the vibration to sound (generally electromagnetic pickups), thus body material has an extremely significant effect on the sound of the guitar.
Back to acoustic guitars, once we have begun to vibrate the soundboard, the air inside the guitar begins to vibrate and resonate as it is pressurized by the downwards movement of the soundboard, and depressurized by the upwards movement of the soundboard. This fluctuating or resonating air now travels through the body of the guitar to the sound hole, where it exits back out to the environment as sound, largely through the phenomena associated with Helmholtz Resonance (which we discussed a while back, as it relates to automotive side-window buffeting and blowing across the top of beer, or soda, bottles).
It’s also interesting to note the how the shape of the body effects the sound. As seen above, there is a lot of structural bracing in the guitar body itself (which makes sense as the body is made from lightweight materials, but must withstand its own weight, use, and sometimes a little abuse. As you might imagine, all of this bracing will effect the vibration and sound and so it must be designed properly to have minimal effect on the sound of the guitar…with the exception of at least two vastly important features, which are not labeled above. The first is the lower bout, which is the lower part of the body that balloons out; this portion attenuates (or reduces/weakens/cuts out) lower tones. The second is the upper bout, which is the upper body portion that balloons out and attenuates higher tones, making the acoustic guitar what we term a band-pass filter, meaning it filters out lower and higher tones (frequencies), only allowing a specific bandwidth of frequencies to pass through.
So far we have seen how an acoustic guitar produces its sound, and this is fine for sitting around the campfire, but what if you want to take your acoustic guitar and play at your friend’s wedding in front of a hundred or so people? Do you expect them to all crowd around silently to hear you play? Hopefully not, and this is where the electric part of electric acoustic guitars comes in. Pickups are used to pick up the vibration of the strings/body and convert it to an output electrical signal that can be fed into an amplifier to produce a much louder sound. In electric guitars, this is generally done using magnetic pickups that utilize the effects of vibrating steel strings over the magnetic pickups mounted on the top of the guitar directly below the strings to produce a signal. In acoustic guitars this is usually not done (for a few reasons, but mainly due to the difference in sound produced, as the sound is decidedly more electric than acoustic when using magnetic pickups), instead piezoelectric pickups are used, which have an added benefit of being able to bypass the interference (that annoying buzzing/static-y sound you hear) often heard when using electromagnetic equipment. The piezo pickups (as they are often called) place a sensor on the soundboard; as the soundboard vibrates, the pressure or applied stress on the face of the sensor changes as the soundboard moves in and out. The change in stress creates a change in strain of the sensor material, leading to a really small change in size and thickness of the sensor material, which sees the change in the material’s geometry as a change in electrical resistance, and registers it a an electrical signal, which is then fed to a pre-amp which essentially just gets the signal ordered up and ready for the amplifier, where the volume is increased, just as with the electric guitar.
So there you have it, just three of the countless things an engineer must consider in the design of an acoustic electric guitar. As always, hopefully everyone learned something new today and now you can go out and rock out (or stay in and serenade) like an engineer! Lastly, take a second and apply what you just learned when you look over the infographic below!
Seeing as Earth Day was yesterday it seems appropriate to learn a bit more about our favorite frenemy (friend/enemy): plastic. More and more consumer products are made of plastic and this means that more and more of our consumer waste is made of plastic. Only very special plastics biodegrade and this causes them to fill our landfills and pollute our oceans, however many of them are easily recyclable. Plastics are polymers, essentially long chain molecules, so they rarely form an ordered structure, like a crystal, they tend to be more like a lot of spaghetti. The way that these molecules, noodles, interact breaks plastics into two major categories: thermoplastics and thermosets.
Thermoplastics are the most common form of plastic. The molecules in these plastics are only weakly bonded to each other by tangling and van der Waals bonds. These can be easily broken and this makes the melting temperature of the polymer pretty low. This makes these plastics easy to recycle because they can be melted and formed into whatever shape desired, used, then melted back down and used over and over.
Thermosets are the other most common form of plastic and these are typically seen as polyurethanes, epoxies, resin and hardener combinations. The molecules in these materials are actually bonded to each other by cross-linking. This raises the melting temperature very high, for most plastics this is above the the point of decomposition so these kinds of plastics burn before they melt. This means that the materials are committed to the shape they solidified in and cannot be turned back to a liquid state and reused making them impossible to economically recycle.
Unfortunately it is usually cheaper to make new plastic than it is to use recycled plastics due to the added coloring and logos printed on bottles and packages. Plastics are also mostly produced from petroleum products, a non-renewable resource. But as technology improves new plastics are coming out that solve some of these problems, for example PLA is becoming more popular and there is a special bacteria that can decompose it. The future of plastics may lie in algae or insect exoskeletons but where ever it is, it’s looking good for the environment!
Team UV arrived home from the National Conference on Undergraduate Research (NCUR) late last night after having traveled from California to Nevada to Idaho to Oregon to Washington, back to Oregon and finally home to Southern California yesterday, amassing over 3,000 miles between travel, the conference, food, hotels, and a bit of tourism.
The conference itself was a lot of fun and proved to be a great opportunity to share our project with students, scholars, and many others from all over the country, while also giving us the chance to check out some of the research that others have been conducting as well. Perhaps one of the coolest moments, was meeting an Eastern Washington University (site of the conference) engineering student who was familiar with our website and who told us he wished he could work on projects like ours in the future, which is a huge win in our books, as it reflects the fact that we have been at least a little bit successful in one of our primary goals here at TeamUV.org: to inspire interest in STEM (Science, Technology, Engineering, and Mathematics), especially amongst the general public. This was definitely one of the cooler moments for our team regarding the past week, as well as the duration of the project in general.
It is unfortunate that we had to run before getting the name of the person we talked to briefly regarding our website after the presentation, but to you we would like to say the following: thank you for your readership and support and please believe that none of us could have possibly imagined a scenario in which we would accomplish/learn/grow as much as we have over the past 12 months of this project when this team was first established last April. If you want to be able to do projects like this, then go for it! Don’t let anyone stand in your way, and as long as you are willing to pour yourself into it, to push yourself to your limits, to get up and fight for what you believe in, and to maintain that level of inspiration, dedication, and determination, there is not a force in this universe that can stop you from achieving your goals. Sure, there’s adversity; maybe it’s financial, maybe it’s administrative, maybe it’s the fact that there just aren’t enough hours in the day, but all of this can be overcome. We raised nearly 85% of our project costs through online crowdsourcing, filed paperwork on a daily basis for nearly three weeks to get to the national conference, put in nearly 5,000 man hours between the five of us over the first 11 months of the project (by a conservative estimate), and slept far less than we’d like to admit, but most importantly, we got to where we are today. Four conferences, representing the Mechanical Engineering department at the Engineering Showcase, a successful website, an excellent team with a great future, and an outstanding project, and we’re still kicking. Remember that seemingly-corny saying “you can do anything that you put your mind to”? Well, it’s time to start believing, because mind over matter is for real and to paraphrase Theodore Roosevelt, nothing worth doing ever comes easily.
All that’s left is to find your inspiration. For me personally, my inspiration comes from our troops. The way I see it, if someone can put their life on the line halfway around the world to protect the freedoms that I enjoy, if they can risk being shot at, blown up, captured or killed in a foreign place thousands of miles from home, possibly alone, starving, and near death (as was the case for Marcus Luttrell during Operation Red Wings), so that people they have never even met before can go on living comfortable lives, how can I possibly complain that my work is too hard, or that I am too tired or too hungry? For me, these are the considerations that make my issues pale in comparison and that push me to keep on pushing myself until there’s nothing left, and then to push further. To all of our readers, identify something worth fighting for and then go to war with your own demons over it, because you can do whatever it is that you want to do and remember, pain is temporary, pride is forever.
Until next time,
P.S. Regular post scheduling will resume Thursday.
Today Team UV will be skipping our usual Presentation post as we are out of state in Washington for the 2015 National Conference on Undergraduate Research, where we will be presenting some of our research that we have conducted thus far in the work on our project. We have traveled some 1,500 miles from California to Nevada to Idaho to Oregon to finally Washington while transporting our propulsion system demonstrator SHEILA-D (Submerged Hydrodynamically propelled Explorer, Implementation: Los Angeles – Demonstrator) and our vehicle DORY (Dynamic Observational Reconnaissance through biomimicrY), and are excited to be presenting our research later today.
More info to come later in the week. Until next time!
A Polish company, Mortax Institute, is in the business of producing body armor systems and is currently working on a liquid based armor that is capable of hardening upon impact. This liquid in question is known as Shear-Thickening Fluid (STF) and can harden at any temperature instantaneously when impacted with a bullet. The liquid armor is capable of providing protection from high-speed projectiles and can also disperse the energy over a larger area. Test performers of the STF for Moratex said “This viscosity increases thanks to the subordination of the particles in the liquid structure, therefore they form a barrier against an external penetrating factor.” The ballistic tests that were carried out have proven that it is resistant to a large and diverse range of projectiles.
The liquid armor’s capability of stopping inbound projectile when combined with the low indentation of its surface creates a safety level that is far higher when compared with the conventional solutions that rely on Kevlar. If a protective vest is fitted to the body, then a four centimeter deep deflection may cause injury to the sternum, sternum fracture, myocardial infarction, or lethal damage to the spleen. Thanks to the properties of the liquid, and to the proper formation of the insert, it’s possible to eliminate near one hundred percent of this threat because of the reduced the deflection from four centimeters to one centimeter.
The team working on this innovative approach to body armor is hopeful that this technology will find applications other than in body armor. I fully agree that this STF, if fully developed, can have a huge impact in the world we live in today.
You’re running late. And now the hour you set aside to workout at the gym is reduced to thirty minutes. The drive to the gym takes about fifteen minutes so simply getting there and back will eat up the entire time budget. You figure you don’t want to skip out on a good workout so you decide that a home workout will have to suffice. Luckily you are a mechanical engineer so you have a few ways to maximize your home workout results.
With these considerations, you’ll be sure to have a good quick workout. Get ready to turn some heads today.
This girl is definitely going places. Inventions to help improve the quality of life in a renewable and sustainable approach has been the main efforts of many scientists and engineers today. A participant in Google’s Science Fair, Cynthia Lam, developed a system known as H2prO that purifies water while simultaneously generating energy. In the images above; the upper portion is used for purification of water, while the bottom part is used for hydrogen generation which is connected to a fuel cell and the base unit for filtration of water.
Cynthia’s device uses titanium to separate the pollutants from the water. With the addition of oxidizing substances (methanol, glycerol, and EDTA) this mixture increases the production of hydrogen, which is used as fuel and to make the decomposition more efficient. Tests show that the H2prO has a 90% efficiency in the removal of organic pollutants, and the entire process can happen in only two hours. Unfortunately, the system is still unstable (even with such a satisfactory production of photocatalyic hydrogen) so data regarding energy production is slim to none. However, Cynthia is not giving up yet and plans to finalize her design to help many people in developing countries!
I used to love wearing contacts. The first time I put them on was like seeing the world in full HD! The only problem is that I have very dry eyes which makes wearing contacts for extended amounts of time very difficult. Scientists at Oculeve have set out to solve this medical problem that affects more than 20 million Americans. The only catch? The very small device jolts you right in the lacrimal!
The implantable neurostimulator is injected or placed via a small incision below the eyebrow or in the nasal cavity. From here, the device sends small electrical pulses to the lacrimal glands to stimulate tear production. This process is controlled by remote and can generate tears as the user needs them. A major design challenge is in the recharging of the device’s battery. Getting to the device to charge every so often is impossible for obvious reasons so a form of inductive charging has to be used. This still leaves the user with placing a charger very near their face to charge the small battery; less painful but very awkward.
Do I see myself using this technology? Not for a very long time! For now, I’ll stay away from zapping my tear glands and use trusty eye drops instead.
More information about tears and the device here.
Until next time…
People spend a lot a their day typing whether it be on a keyboard, smartphone, or a card reader. Researchers at MIT noticed the value of this daily habit, and are putting it to a secondary use; they’ve developed software that can gauge the speed at which a typist is tapping the keyboard to help diagnose Parkinson’s disease. In order to type a word, your brain has to send signals down through your spinal cord to the nerves that operate your fingers. If your central nervous system is functioning perfectly, then you should be able to tap most of the keys at a fairly constant rate. But a number of conditions might slow the signal from the brain to the fingers, such as sleep deprivation (which slows all motor skills) and diseases that affect the central nervous system, including Parkinson’s.
For the first version of this study, the researchers were looking at typing patterns that indicated whether a person was sleep-deprived or well rested. They created a browser plug-in that detected the timing at which the volunteers hit the keys and found that the people who were sleepy had a much wider variation in their typing speed. They found similar results in their preliminary test with Parkinson’s patients; the 21 typists with Parkinson’s tapped the keys at much more variable rates than the 15 healthy volunteers. The researchers called it a “window into the brain”.
Right now, the algorithm they’ve developed is not refined enough to distinguish Parkinson’s patients from people who are sleep deprived, though the results might be clearer after a number of trials. The researchers plan to conduct a study with a larger group of subjects, but they hope that this type test could eventually lead to earlier diagnoses of Parkinson’s. Today most people are diagnosed after they have had symptoms for 5-10 years and to distinguish Parkinson’s from other conditions that might affect a person’s motor skills, like rheumatoid arthritis. They are currently developing a smartphone app that can test participants even more easily.
After presenting Dory (Team UV’s senior project) to our adviser and a few interested technicians, I found relaxation in the beautiful landscapes of the Central Coast. During the trip, my girlfriend and I made a visit to Monterey Bay Aquarium on Cannery Row. To our surprise, we found a lesson in science and engineering in the most unsuspecting place…the Sea Otter Exhibit!
The incredibly cute creature above is quite the wet weasel! Belonging to the weasel family, sea otters live along the coasts of the northern Pacific Ocean. Aside from being adorable and cuddly they have a few survival traits that make them scientifically interesting. Sea otter fur is one of the most dense around with up to a million hairs per square inch. They need this much fur because they have no blubber! Living in freezing water is made doable by this dense fur which is fluffed from hours of daily cleaning. Fluffy fur traps air between the otters skin and the freezing Pacific water, where it acts as a thermal insulator.
Layers of air can act as a great insulator, reducing the amount of thermal energy lost to the environment. We see this “phenomenon” practically everywhere; birds “fluff” up their feathers and people wear layers of clothing to trap air close to their skin.
Thermal energy flows in one direction: from a warmer body to a colder body. Insulation such as air is used to reduce the rate of heat transfer in that direction. Many popular building materials use trapped air pockets to slow convective heat transfer (heat transfer due to fluid motion, which is caused by density changes in the heated fluid for the case of natural convection) while also reducing conductive heat transfer (heat transfer through a body due to physical contact). These materials are placed between walls or along pipes to control thermal energy flow. Another popular application is in double pane windows where an air space acts as a thermal insulator between the inside and outside environments.
It’s cool to see the science behind nature especially when you can see its application in other forms. Who knew I would continue to learn even while on vacation!
Until next time…
Today’s post will be a bit accelerated due to time constraints imposed by a long To Do List for Team UV in the coming weeks as we prepare for more testing, analysis, conference, and possible journal submissions, but I thought it would be a little fun to talk about role models in engineering today. First off, a major issue is that there really aren’t many widely publicized role models in the world of engineering, which actually stems from a fact relating to the average academic process.
Growing up, we all take classes in fields such as English (or a comparable language class if you are in a country where English is not the primary language), Mathematics, Art, History, Biology, Chemistry, Government/Politics, and (maybe) Physics, but the only people who truly take engineering classes are people who are going to become engineers. This, unfortunately, creates a huge disconnect between the engineering world and that of the general public; the public knows what a historian does, what a businessman, artist, or chemist does, or at least has a fundamental understanding of what they do, but the only ones who truly know what an engineer does, are usually the engineers themselves. This directly translates to the lack of publicity of engineering role models, in that it is not very often that a movie, or TV show, or children’s book (for example) is produced that focuses on an engineer as a role model; if there is an engineer in the story, the role of the engineer is usually vastly misunderstood and often misinterpreted. No one is truly to blame for this, it is simply a consequence of the fact that only engineers truly take engineering course work (after all, should the general public be forced to struggle through extremely difficult engineering courses if they are not interested in engineering?). So how can we remedy this?
The best way is to help form a stronger connection between the general public and the world of engineering and, generally speaking, the most effective way to do this is by trying to inform the public about engineering at a younger age. What is the perfect vehicle for this kind of education? The use of role models through TV personalities, story book heroes, and even public speakers. Below I will quickly introduce you to a few engineers who have been working very hard to introduce a younger audience to engineering in the hope of inspiring the next generation of engineers.
Bill Nye “the Science Guy” is actually a mechanical engineer; bet you didn’t know that! Nye received his B.S. in Mechanical Engineering from Cornell University in 1977 and has gone on to receive many honorary degrees including a Doctor of Science honorary degree from Rensselaer Polytechnic Institute, an honorary doctorate from Johns Hopkins University, an honorary Doctor of Science degree from Willamette University, and an honorary Doctor of Pedgogy degree from Lehigh University. Nye is of course known for his educational television program “Bill Nye, the Science Guy” which spanned 5 seasons and 100 episodes (from 1993-1998) and taught a young audience about highly complex subjects such as heat transfer (for example) in simple and fun ways, often using experiments that could be performed by kids at home with their parents. Bill Nye helped to influence an entire generation of future scientists and engineers; one can only wonder how much greater the impact could have been if the show shined the light on Nye’s role as an engineer. None-the-less, Nye’s work has had a major impact and helped to show that science can be fun. If you are unfamiliar with the show, I highly recommend you seek it out and am sure you can find old clips on YouTube. Most recently, Nye was working on an interactive video game that would utilize lightweight wings that could be strapped to the arms and moved and flapped around to teach kids about the aerodynamics of flight.
Debbie Sterling is a name you may not know, but she is an outstanding role model never-the-less. Sterling holds a degree in Mechanical Engineering/Product Design from Stanford University and upon graduating, did exactly what engineers are taught to do: she identified a problem and came up with a solution. Sterling decided to pinpoint the issue of gender under-representation in engineering, pointing out that only 14% of engineers worldwide are female. I can personally attest to the truth of this fact as, over my 5.5 year undergraduate career, I was made all too aware of the lack of gender diversity in my classes. This issue is magnified in mechanical engineering, which in my experience shows far lower numbers of females than other fields of engineering do. In my average mechanical engineering class throughout my undergraduate career, there were likely on average 1-2 females out of a class of 30-35 students on average; some classes had as many as 4 females, while many did not have any at all. In order to remedy this issue, Sterling has created a line of toys specifically targeted towards girls at younger age levels that aim to inspire interest in engineering. She essentially has made the female equivalent of the builder sets and simple machine toys that many boys enjoyed growing up, but that many girls were kept isolated from. Sterling’s company GoldieBlox is making great strides and I highly recommend that you check out their website.
Elon Musk is the last person that I will list. Some of you may not know who Musk is, while others of you might be the type to follow his every move. Musk earned two B.S. degrees, one in Physics from the University of Pennsylvania and one in Economics from the Wharton School. Following these two degrees, Musk began his Ph.D. in Applied Physics (which is often very similar regarding coursework to both electrical and mechanical engineering), but left the program two days later to start his career as an entrepreneur, going on to start some very successful companies, namely: Zip2 (a web software company that was bought up by Compaq in 1999), X.com (an online financial services company that later became PayPal after a merger with Confinity), SpaceX (short for Space eXploration), Tesla Motors (an electric car company), Solar City (which Musk came up with the concept of, with his cousins actually starting the company, which is now the 2nd largest solar power system provider in the U.S.), and is currently setting up Hyperloop (which would provide a 350 mph+ form of ground transportation between Los Angeles and San Francisco). Musk is on this list for a different reason, while he has worked as an engineer, he is on this list more for the companies that he created. All of these companies are revolutionary by nature and thus the companies inspire interest among many future engineers, while Musk helps to get the word out through public appearances and his role as the face of these companies.
There you have it, three engineering role models of today. Engineering is such an amazing field and there are many people out there who could have made limitless contributions to the STEM (Science, Technology, Engineering, and Mathematics) fields if they were only educated about engineering as a possible career option at a younger age. Having said this, it is never too late, if we continue to take positive steps today such as establishing elementary school science/engineering clubs and programs or more widely publicizing engineering role models (such as Debbie Sterling, for example), we can help to produce the finest generation of engineers the world has ever seen tomorrow. It is said that you can do anything that you put your mind to…I wholeheartedly believe this, but in order to put your mind to it in the first place, you must know that “it” exists.
Another round of Pop Up Design is here with something that’s been on my mind for a while now. I have been driving a 2004 Volvo XC90 for the last six years now and with it close to 180K miles, it’s been quite the trooper! I have put on at least 100K miles since I first got it back in my sophomore year and although it’s still running strong, it’s time to consider retiring it from daily driving duties. Don’t get me wrong, my “Tardis” has been extraordinarily reliable and versatile in its uses but it’s time to get away from the “Dad Car” look. With so many cars on the market now and my very high standards in automobiles, I often wish I could design my own car. This dream car would be built to my high standards of performance, looks, repairability, and sound…yes, sound. For this Open Mind, I will share three of the most important considerations for designing my dream car.
Sound: Often times what draws my attention to a car is something way before I even see it. True car enthusiasts can name a car just by the way it sounds! For me, nothing beats the sound of a well tuned V8. I would take the sound of 8 cylinders over turbocharged 4 cylinder engines or even some inline 6 cylinders. I find it awkward when sport cars and even some race cars sound like lawnmowers or air vents. I guess it stems from the love of my Camaro’s rumbling and floor-shaking 350 V8. With a well tuned exhaust, my dream car would turn heads in all directions as people try to guess where that heart racing sound is coming from.
Repairability: There are some cars out there that can’t be serviced easily. Even getting windshield wipers that fit correctly can be a costly task. If I can’t stop by an Autozone down the street and get the parts I need, that car is not for me. Parts for my dream car would not be custom, one-off pieces, rather a mixed array of the best parts from all automakers. That way I could easily and quickly get the parts I need; the day I need them.
Looks: I have a confession to make…I like boxy cars! To me, there’s nothing cooler than a ’65 Chevelle or a BMW e30. I know boxy styling may not be the most aerodynamic but I’m willing to overlook that. Also, I think Mazda had a great idea with doing a hidden 4-door design with the rx8 but I would look to improve on that even more. I would make the seams as invisible as possible while allowing for full access to the back seat. A 4-door sports car would give my dream daily driver more life as kids start coming into the picture.
Not many people will design their own car but it doesn’t hurt to dream. Maybe one day I will find the perfect 4-door V8 sports car that looks like a 2-door. In the meantime I will focus on getting a “dream job” to pay for my “dream car”!
Until next time!
Most people have probably had the experience of driving in a car on the freeway and rolling down their window only to end up with an awful buffeting sound that hurts their ears. People familiar with this phenomenon often refer to it as “side window buffeting”; but in fact, this phenomena is actually caused by something known as Helmholtz Resonance. With that, let’s jump right into it!
As air flows over your car, it decreases the pressure in the flow due to what’s known as Bernoulli’s Principle; that is, in the absence of energy input and losses (which we will assume to be zero for this simple exercise in thought), if the flow is assumed to be incompressible (valid for the relatively low car speed), inviscid (negligible friction, as follows from our assumption of no losses), and steady (not changing with time), then if we assume that the change in elevation is negligible (perfectly valid for air, which is not very dense, over the 5 feet or so from the top to the bottom of your car), we can ascertain that if the velocity of a streamline increases, the pressure decreases, and vice versa.
Now, let’s roll down a window while we are travelling on the freeway at elevated speeds. Remember, since we are moving, the pressure of the flow is lower than that of the ambient air far removed from the vehicle (outside the boundary layer); however, the air inside our car is essentially atmospheric pressure (i.e. the standard pressure of the atmosphere, no lower, no higher, just like the ambient air far removed from the vehicle), or perhaps even a little bit higher than atmospheric due to the pressurization from your air conditioning. So now we have the window open with a low pressure flow outside the car and a higher pressure inside the car.
The higher pressure air inside the car wants to go to the lower pressure region, so it is pulled out of the car. Now, we might expect that once enough air flows out to equalize the pressure, the flow will normalize and stop pulling from the car, but this is not the case; the air flowing out of the car has both mass and velocity, the two implicit components of momentum. Thus the air flowing out of the car has momentum and overshoots the equalization pressure, essentially giving away too much pressure from the inside of the car and thus leaving the car’s contents at a lower pressure now than the flow outside the car (creating an effective vacuum). Now the flow outside wants to move inside, but this flow has momentum as well and so it overshoots the equalization pressure and leaves the inside of the car over-pressured. As you might expect, this process can continue, with the flow moving back in forth across the window opening, getting larger and larger, until eventually the damping characteristics of the air itself keep the amplitude of this oscillation from increasing further, thus leading to a steady state oscillation of sorts.
This oscillation or flow buffeting is exactly what you are hearing, because as the flow buffets, it produces moving pressure waves with it, which our ears pick up as sound. Not only can this buffeting sound be very irritating, but it can also be damaging to your ear drums (which are in effect membranes that effectively convert vibration from pressure waves into sound); this can be especially true if you happen to be driving at the speed that maximizes the system resonance (which results in this Helmholtz Resonance). To better understand this, imagine pushing someone on a swing, if you push them and let go, they oscillate about the vertical swing position until the action of gravity, drag, and frictional losses brings the swing to rest. Now if you give them another push while they are moving backwards towards you, they will continue to swing, but not as fast or high as they could have because you pushed them before they got to the top of the arc. This time, you wait for them to get to the top of the arc (as far back towards you as they travel), and just as they have switch directions (and start swinging forward), you give them a big push. This time, you have added to the energy without cutting short their motion; if you continue to do this, they will swing higher and faster each time. Back to the car, if you are moving with the right speed, the air flowing into or out of the car from the next (upstream) batch of air can synchronize with the pressure osciallation already in place, leading to an increase in the oscillation amplitude (increasing the effective strength of the flow buffeting pressure); this is what happens when the buffeting gets really loud, to the point that it hurts your ears. Moreover, the pressure buffeting in and out of the window disrupts the airflow around the car, leading to vortex shedding, as can be seen in the video linked to here). So what can you do to stop this?
Well, you could slow down in order to avoid the resonance, or speed up for that matter (but not only could you reach another, higher resonant point, but you could also get a speeding ticket, which is no good). You could also roll down your window more or roll it up less (a larger opening will provide a deeper/lower pitch sound and a smaller opening will provide a higher pitch sound) or roll down other windows to relieve the pressure in the car [interestingly, rolling down the opposite, diagonal window usually provides more relief due to the direction of the airflow (rearwards due to the car’s motion and across due to the motion of the buffeting) , i.e. the back right window if the front left one is already down]. Another interesting option is that some cars (like the Chevy Volt) now come with so-called “window air deflectors” that re-route the air further from the window without messing up the car aerodynamics too much, as they deflect the air at an angle that allows it to rejoin the car immediately after the windows.
It should be noted, however, that “side window buffeting” is not the only place that you can see Helmholtz resonance; this can also be seen in the old bar trick of making noise by blowing over a bottle (as pictured at the beginning of the post), many musical instruments, in some automotive exhaust systems that aim to change the sound of the exhaust, and even in some silencing applications in which the created noise is used to cancel out unwanted noise through destructive interference (this can be seen in some aircraft engines, automotive mufflers, and even weapon suppressors/silencers, wherein chambers are used just like the cavity inside the car to produce the noise cancelling pressure waves). Lastly, it’s also worth noting that this whole Helmholtz Resonance effect is more apparent on newer cars than old ones mainly due to the fact that newer cars are more streamlined, which is great for reducing drag, but brings the airlow closer to the car, thus inspiring this phenomenon to occur more easily.
Well, I hope everyone learned something today; now you can go tell your friends about the science behind that annoying thumping! Be sure to check back for Ben’s Open Mind post on Sunday and, I almost forgot, sorry for the 1 hour post delay, I am out of town and do not have readily available Wifi.