Yours truly driving my 1970 Camaro (picture taken by a passenger, don’t worry).
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.
E30. Photo Credit: carjunkies.com
Chevelle. Photo Credit: bangshift.com
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”!
Top: Helmholtz resonance over a bottle (Photo Credit: Youtube.com; Nick Moore/Nik282K) Bottom: Automotive airflow diagram (Photo Credit: hitechcae.com)
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.
Inverse relationship between velocity and pressure; flow acceleration and deceleration due to flow area change. Photo Credit: wwk.in
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.
Oscillation amplitude increase due to resonance. Photo Credit: AfifTabsh.com
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.
Chevy Volt window air deflector (lower right corner of the picture). Photo Credit: thecarconnection.com
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.
Constructive and destructive interference. Photo Credit: animals.howstuffworks.com
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.
Liquid metal motor in action. Photo Credit: Gizmodo.com
A recent article published in Nature describes experiments that involve a special alloy of metal that is liquid at close to room temperatures. This alloy interacts with a surrounding fluid, usually water allowing it to propel itself. It is a huge feat, motion before has come from some form of external manipulations of magnetic fields, as in electric motors, or forced changes in pressure, as in hydraulics. This self moving metal can create motion on a much smaller scale leading to even smaller devices. Imagine a small camera that can zip through your bloodstream and sweep up any bad cholesterol lying around or guide a surgeon’s knife in a life saving procedure.
The Journal of Nature is one of the largest scientific journals in the world, many groundbreaking advances in science are published through it. While subscribing to the journal itself is not cost effective for most individuals they do offer an RSS feed that provides brief summaries of the articles published in their recent issues. Check it out here: http://www.nature.com/nature/newsfeeds.html
Dory and Sheila-D in the top row and post-presentation team congratulatory pizza and beer at the Cal Poly Pomona brewery (Innovation Brew Works) in the bottom photo. Photo Credit: Andrew Blancarte
First off, we want to apologize for missing our Thursday post, it has been a very hectic week for Team UV with almost all of the members going without sleep for 30 hours and above at some point or another; for example, I personally received about 8 hours of sleep total between Sunday morning and Thursday evening and at one point had to go about 30 hours without eating in order to get everything accomplished, but alas!, it was for a good cause and now Team UV can finally relax! (well, relax relative to other people, haha)
This past week and a half Team UV has had a week straight of building, testing, and programming for our vehicle, final exams, grad school visits, reports and projects due, graduation stuff, and of course completing our senior project! On Thursday, we delivered our final project presentation to the Mechanical Engineering board responsible for assigning our grades (we all received A’s), turned in our 140 page project report, and did a live demonstration of our vehicle Dory (Dynamic Observational Reconnaissance through biomimcrY). Dory (our Phase III vehicle) can be seen in the picture above, next to our Phase I propulsion system demonstrator Sheila-D (Submerged Hydrodynamically propelled Explorer, Implementation: Los Angeles – Deomonstrator)! (Read more about Sheila on our About page)
So this marks the “official” end of our senior project; however, this does not mark the end of the project altogether. We still have a lot of work to do regarding improving the build, adding more features, completing more advanced testing, and overall producing a more polished solution. Additionally, we will be attending the National Conference on Undergraduate Research (NCUR) at Eastern Washington University from April 16th-18th, the California State University system-wide Student Research Conference (CSU SRC) from May 1st-2nd (we are attending this because we won our session and award money at the Cal Poly Pomona Student Research Conference on March 6th), the Cal Poly Pomona (CPP) Senior Project Symposium at the end of May, and hopefully the CPP Symposium Showcase at that same time (this highlights the top project team from each engineering department).
Additionally, we will be looking to submit to some journals, quite possibly looking into at least one patent. Lastly, this website will continue publishing posts until the project ends, at which point these types of posts will continue on EngineeringAFuture.com. Anyways, thank you all for your continued support and I would like to remind everyone that we still have our fundraising campaign (GoFundMe.com/TeamUV), which will continue as long as the project is running as we still have quite a few costs ahead of us!
Please check back in tomorrow for a Well Read post from Ben!
Note written by an Army Special Forces member on the door of an MRAP in Iraq: “This truck saved my life as well as 5 others on 02 Apr 08 at 2300 L in Basrah, IZ.” Photo Credit: Wikipdeia.org
First off, we want to apologize for missing our Thursday post, it has been a very hectic few weeks for Team UV; to make up for the missed post, we will have a post this upcoming Monday (03-23-15) at 1000 hours sharing a little bit about what Team UV has been up to recently and some major accomplishments. In the mean time, however, I’ve got an Open Mind post to share!
Today we are going to be talking about armor…the stuff that helps to protect the men and women who dedicate their lives to protecting us. More specifically, today we are going to talk about some of the most important revolutions in ground vehicle armor over the last century. Without further ado, let us begin:
Sloped Armor Although one of the first recorded uses of sloped armor was on Confederate ironclad warships during the Civil War (it is interesting to here note that most early tanks were actually designed by naval engineers), the technology saw its first true ground vehicle implementation in French WWI era tanks. Further, the technology was brought to the spotlight through its use in the Soviet T-34 medium tank, and was made infamous by the seemingly invincible Panther (medium) and Tiger II (heavy) tanks used by Nazi Germany in WWII (that is, until the fire superiority, vast numbers, speed/agility, and overall ability of the US M4 Sherman tanks, combined with the invaluable experience of the Sherman tank crews, and the American air dominance proved overwhelming to the Axis powers). This technology, although very simple conceptually, had colossal implications.
Sloped armor of a Russian T-54 tank. Photo Credit: Wikipedia.org
As shown above, this sloped armor is just that…sloped. This actually has a few profound effects:
For a projectile coming in horizontally to pierce the armor, it has to pass through a greater thickness of material due to the angle that the plate makes with the horizontal.
More efficient use of material; a sphere has less surface area than a cube for the same volume and so if you want to envelope a volume with the least amount of material, you try to approximate a sphere by using more and more angled pieces.
Approximation of a circle by adding more and more angled segments. Photo Credit: mathandmultimedia.com
Deflection. Assuming an optimal combination of armor vs. projectile materials, an incoming projectile might ricochet straight off of the armor or at the least have its path deflected due to the angle of incidence as it passes through the material.
Slat Armor First used by the Germans in WWII, slat armor (a.k.a. cage armor) arose to greater prominence during the Vietnam War and has experienced renewed interest recently in the Middle East. The general idea behind this armor is that by simply putting a cage of slats around vital/unprotected parts of a vehicle, an incoming anti-tank weapon (say a rocket propelled grenade, or RPG) can either be forced to detonate prior to contacting the vehicle body itself (thus disrupting the path of the shape charge, which was originally intended to pierce into the vehicle) or by actually damaging the warhead beyond operational capability (effectively crushing it so it no longer works).
Stryker with slat armor. Photo Credit: defense-update.com
Slat armor is a relatively inexpensive, simple means of protecting ground vehicles; unfortunately, this armor only has about a 50% working rate and so is generally used in addition to other, more capable armor, bringing us to the next item on our list.
Reactive Armor Easily one of the cooler revolutions in armor over the last century, reactive armor provides an opposite reaction when it experiences impact from a weapon. There are many types of reactive armor, but explosive reactive armor is the most common. This armor consists of a high explosive situated between two plates that effectively helps to offset the energy from the weapon that contacts it; when a projectile pierces the top plate, the inner explosive reacts, pushing the two plates outwards…since the outer plate is open to the atmosphere (whereas the inner one interfaces with the vehicle structure), the outer plate flies out further (taking the expended energy with it and generally destroying the projectile itself!).
Russian T-72B main battle tank with reactive armor panels. Photo Credit: army-technology.com
This armor saw its first combat usage in the 1982 Lebanon War by the Israeli Defence Force and has found very wide usage today.
Spall Liners Spall liners are an interesting addition to traditional armor that came about to solve the problem of what might happen if a shape charge were to successfully penetrate a vehicle’s hull. The actual scientific explanation of spalling and the action of spall liners is truly quite complex, but from a superficial view, it can be stated as follows: spall liners essentially protect the crew inside the vehicle from fragmentation in the event of the hull being pierced. The liner is made of highly compliant material that can in effect absorb the energy and shrapnel associated with the fragmentation.
Fundamental illustration of spall liner operation. Photo Credit: innovationtextiles.com
These spall liners found their first use during the Cold War.
V-Hulls V-Hulls are a novel idea that first arose in the 1970s as an answer to the increased use of anti-vehicle road explosives (similar to the improvised explosive devices or IEDs that have become unfortunately common in the Middle East today) during the Rhodesian Bush War in the south-eastern regions of Africa. The aptly named V-Hulls are essentially a design modification of the vehicle that alters the bottom of the vehicle from being flat to being V-shaped, which helps to redirect the shock wave from an under-vehicle blast away from the vehicle and its passengers.
V-Hull on a Nigerian Otokar Cobra APC. Photo Credit: beegeagle.wordpress.com
This design has been vastly successful and has become a very common feature on modern infantry fighting vehicles (IFVs) and armored personnel carriers (APCs) during the conflicts in the Middle East, where the threat of IEDs has become of great concern.
Run-Flat Tires The last innovation that we will cover in this post is the advent of run-flat tires, which have been used widely for military, law enforcement, government, aid groups, and protection of high-level executives since as early as the 1930s with the Michelen self-supporting run flat tires that would run on a foam lining if punctured. Today’s military vehicles use a slightly different type of run-flat tires referred to as auxiliary-supported run flat tires.
Auxiliary-supported run flat tires. Photo Credit: Wikipedia.org
These tires essentially use a secondary support ring capable of supporting high weights at elevated speeds for long periods of time. If the tire is punctured (or perhaps shot), the vehicle can continue on its way or get out of Dodge quickly. Another big plus is the fact that these can be placed inside of standard tires and thus do not require specialty tires/wheels.
Well there you have it: some of the coolest and most useful armor technologies to emerge for ground vehicles over the last century. These technologies continue to help ensure the safety of the men and women who work to protect us (whether that be in the military, law enforcement, or even aid workers). Not only are all of these technologies vital to survivability considerations, but they also represent a fascinating field of engineering that is improved on through advance research and development on a daily basis with all kinds of crazy solutions up and coming, the likes of which most would not even dream of. Anyways, as always, thanks for the support and have a great remainder of your weekend. Until Monday!
The newest addition to the International Space Station (ISS) could be launching as early as September 2015! Bigelow Expandable Activity Module (BEAM) is a combined effort of Bigelow Aerospace with NASA and SpaceX and it is exactly what it sounds like, an expandable space habitat that will find residence at the ISS for the next two years. In those two years, astronauts will be inspecting and gathering performance data to see if it really is a viable habitat that can resist the rigors of orbit including radiation, loads from accelerations, and even micrometeorites. When it is not being inspected, it will possibly serve as a lounge area for astronauts or as an additional laboratory and that’s really the beauty of it. It can be anything you want it to be, it’s more space in space! The keyword in its description is “expandable” as astronauts will activate a pressurization system and expand the BEAM to roughly the size of a 10×12 foot bedroom using air stored within the packed module. What is so inspiring about the launch of the BEAM is that it could one day replace the ISS altogether. The inflatable segments can be connected together to make larger and larger habitats. If it’s performance is promising, it could mean a future where space hotels on the moon are possible or even full-fledged factories in orbit! There is just so much more room for activities! It’s making my head spin…
Futuristic movies usually portray a world where robots are commonplace and yet here in the present they’re not nearly as accessible, at least not the humanoid ones. If you just want a robot that can vacuum your floor read no further! One of the major things in humanoid robots is the development of linear motion devices. If you want something that spins we’ve got that covered but making something move in a line, now that’s a bit more difficult. There are ways to do it and some of them would make great muscles for robots!
First off, there’s the idea of having a motor drive a screw and use that to move a nut back and forth. This is a pretty common way of getting robust linear motion into many applications especially where accuracy is a concern. This is because for every turn of the motor the nut is going to move a small and easy to determine amount. However these can be slow and can wear out rapidly.
Next let’s look at hydraulics, these are pistons powered by piping high pressure fluid into them and forcing the piston to extend or contract. They are very powerful and can be made fairly accurate, used commonly in industrial applications for lifting things. They can also be miniaturized to fit onto a robot, unfortunately they require a fair amount of piping and a powerful pump.
Thirdly lets look at a nickel titanium alloy that goes by the brand name Nitonol. This material will contract if the temperature is raised due to a transformation in it’s internal crystal structure. Essentially the atoms that make up the material shift around and reorder themselves into a more tightly packed structure reducing the length of the overall wire. This means that when electricity is passed through the wire it will heat up due to it’s resistance and the heat will cause it to contract. This allows for linear actuation in a very small package, however the change in length is also quite small.
The world of tomorrow will probably have more prevalent humanoid robots, and they just might be flexing muscles made with one of these actuators!
Yes you read correctly, the flying boat. A hydrofoil is a term used to describe a watercraft whose hull is fitted underneath with foils (wings essentially) that produce lift to clear the hull from the water. The overall effect of this is reduction/elimination of the viscous and pressure effects on the hull which essentially means reduction in drag and allows a more efficient use of the craft’s propulsor allowing it to achieve higher speeds. So all that sounds like a bunch of mumbo jumbo, but I think this video will allow you to visualize exactly what I am talking about.
At low speeds the outside of the hull and foils sit submerged underwater but as the craft speed increases, the foils create lift. The amount of lift the foils can create depends heavily on geometry and angle of attack (as mentioned in my previous post). In simplest terms, the velocity of water over the foil is faster above it than that below and this creates a pressure distribution that is different on the top and bottom surfaces of the foil. The figure below shows the typical pressure distribution for a cambered (unsymmetrc) airfoil. The lower pressure exists above the foil then below, therefore “lifts” in the direction of the lower air pressure. A more rigorous explanation of how lift is produced might come in a later post but for right now this basic explanation will suffice.
Depending on the design of your hydrofoil, the angle of attack for the foil may be constant or variable but it will most likely be constant. With this in mind and using the basic lift equation, you can determine how much lift you can theoretically produce from your design given an operating velocity. Once this lift force is equal to the weight of the hull, crew, and cargo on your craft, voilà, the hull is lifted out of the water and you have a flying boat. Of course, there is definitely more complexity to the design but this gives you a basic idea of how a hydrofoil works. Hope this inspired some interest in a very cool, niche type of water craft.
This robotic glove, the “Teacher”, is designed to help you improve your drawing skills. It attaches to your hand and the machine coaches you to draw by forcing your hand to perform certain motions. The idea is that your hand will eventually develop the proper muscle memory and be able to draw free-handed.
Saurabh Datta, an engineering student from the Institute of Interaction Design Copenhagen, developed the glove for his graduation thesis. Initially, the equipment was designed to teach him how to play the piano. In it’s latest version however, the Teacher can help anyone without a natural born talent to draw through simple repetition. The robot forces your hand to repeatedly execute a series of basic drawing movements. The repetition of these movements end up being transferred to the muscle memory of your fingers, causing you to be able to repeat the movements naturally without the use of the glove. The idea of the glove is basically to “program” you so your lines become aesthetically better. The glove has no ability to interfere in the creative process so it’s still up to you whether or not to be able to put on paper something visually attractive.
I am not an artistic person but once I obtain one of these gloves who knows. You might see one of my drawings in a museum near you! 🙂
Nerf gun office war. Photo Credit: hrsolutionsinc.wordpress.com
Prompt: You are in an office and the annual Office War is about to begin. You have less than an hour, a desk (w/ pullout drawers), rolling chair, computer, keyboard, mouse (old roller-type), mouse pad, stapler, staples, three hole puncher, desk lamp (old fashion bulb), rubber bands, paper clips, pushpins, envelopes, printer, printer paper, clicker pens, No. 2 pencils, a white eraser, highlighters, 15 ft. Ethernet cable, scientific calculator, engineering pad, corded desk phone, a gallon water jug, a tin of Altoids, a hot cup of coffee (in a ceramic mug), and a frozen 4 lb. steak. It’s either you or them, and remember you are a mechanical engineer, not a tinkerer. Go!
NOTE: DO NOT try or create any of these ideas at home. This is purely for fun and we will not be held responsible for your actions! Enjoy!
The alarms have sounded, the office war has officially begun. You wipe the citrus flavored energy drink from the edge of your mouth and put the computer on standby mode. Confidence oozes from your pores like hot molasses, you stare at the closed door in your office and announce without fear, “Come at me brethren!” Footsteps suddenly stop, and redirect towards your position. You put your plan into action.
The Trap: You grab the hot mug of coffee and let its bitterness energize your blood stream. Looking for a cloth to wrap the mug, you decide the shirt on your back will do. Taking the metal 3 hole punch you smash the wrapped mug into jagged shards and sprinkle them at the entrance of your fortress (office) along with push pins facing up. And finally using the telephone cord to create a trip wire for any of your mates who will be bursting from your door.
CQC (Close Quarters Combat): Eventually the bodies will pile up at the door and initial trap will prove to be ineffective, you need to ready to defend and attack directly. With the lamp shining bright you break the bulb filling the room with darkness. This will hinder the incoming attackers vision and allow you to use the faces of enemy’s as the resistance to complete open circuit of the lamp. Quickly you empty the drawers from your desk and disassemble them for a large wooden slab making for a wooden shield that can be strapped to your forearm with your computer mouse’s wire.
The Steak Flail: You can’t stay plugged into the wall forever, you grab the frozen steak and tie it to the end of the 15 foot Ethernet chord and swing it like a medieval flail. For added protection, you take the Altoids tin and plastically deform it into a shiv to drive into the hearts of your enemies. Now armed with a long and short distance weapon and a shield, you work your way over all the bodies in your office and out the doors to victory.
Hopefully an office purge will never happen but my wish is that this article may somehow help you strategize and survive if it does. What would you do? Comment below, let me know.
With all the talk about drones lately, especially Amazon’s drone, I thought this would be cool to mention. Today, I want to introduce you to Gimball! The collision tolerant drone!
There is always a learning curve when first piloting a drone. You may not be as good as you think when you keep knocking into things. The last thing you really want is to watch your drone engage in a mid-air collision, but for Gimball it is it’s main selling point. Described as the first “collision tolerant drone” it won $1 million at the Drones for Good international competition held in Dubai.
It was created by Swiss company Flyability and it utilizes a rotating spherical outer cage that means it can be used safely in close proximity with people. Designed to enter hostile environments such as burning buildings and radioactive sites, Gimball maps its surroundings and can roll across ceilings and floors, navigate restricted areas, and transmit RGB and infrared images back to disaster relief services. Surrounding the multi-axis gimbal system with its built-in camera is a carbon fiber outer cage that absorbs the shock of any collisions and the gimbal system means that the cage can roll about independently of the camera.
Connecticut-based company, GuardBot has recently released their take on an autonomous broadcasting, reconnaissance, and security robot. What began as a bot aimed for use on Mars, is now a potential patrolling robot for the US military. Guardbot, also the name of the bot, is capable of tackling various terrains from sand, grass, mud, and snow to even water. In solid to slightly wet environments, it can achieve a top speed of 6 mph and can even climb hills up to 30 degrees in slope. In water, Guardbot can achieve a top speed of 4 mph, still perfect enough for guard duties.
Going for a swim. Photo Credit: cdn.ft.rs
Guardbots can be ordered in a range of sizes from 4 inches to 9 feet in diameter but the standard size is 2 feet. Inside the bot, a number of electronic controls are housed to achieve various tasks. These tasks are set by the client and anything from night vision to laser scanners can be installed. It also features live streaming, high definition cameras and a pendulum-stabilized electronics tray to keep everything oriented upright.
Tiny GuardBot for home use. Photo Credit: soocurious.com
Although very different from our project, the goals of these two devices are the same. Both can be used for reconnaissance and security missions but can also be customized to meet other needs. Our project is capable of being used in tracking, exploratory, and guarding scenarios (in addition to our primary application of ISR). GuardBot can also be used to patrol parking lots and in emergencies where explosives or chemicals are present.
There has always been a desperation to move our dependency from dirty, finite fossil fuels to a more cleaner and sustainable fuel source and since the start of the decade there has been a rapid boom in the adoption of solar energy harnessing. Solar panels are becoming more efficient and continuous developments in the tech mean that it’s being adopted in unexpected areas not well-known for having loads of sunlight. Here are the top 10 performing countries in solar energy!
1. Germany – 35.5 GW – Germany was the world leader back in 2010 with 9.8 GW as well.
2. China – 18.3 GW – Even though China has a massive and dense population and known for its smog. It ranks pretty high on this list!
3. Italy – 17.6 GW – Italy was in 5th place in 2010 and has risen up to 3rd place as of the end of 2013.
4. Japan – 13.6 GW – Japan has increased their solar capacity by 500% since June 2010. Unfortunately they have slipped from 3rd to 4th place as of 2013.
5. United States – 12 GW – The United States increased their capacity by 750% and it is expected to grow significantly in coming years.
6. Spain – 5.6 GW – Spain was once the world leader back in 2008 with 2.6 GW. Complexity and delays related to a new government subsidy program and a decrease in energy demand led to this drop.
7. France – 4.6 GW – France has continued to benefit from its well-designed FiT for building-integrated photovoltaics (BIPV), but the country’s solar growth has been slowed by a lack of political support for solar incentives.
8. Australia – 3.3 GW – Australia boasts some of the greatest solar potential in the world. Solar power costs less than half what grid electricity costs, although the current government is considering scaling back the federal Renewable Energy Target, which would slow if not stop the country’s upward trajectory in these lists.
9. Belgium – 3 GW – A surprisingly strong contender over the years, Belgium’s success was from “a well-designed Green Certificates scheme (which actually works as a Feed-in Tariff), combined with additional tax rebates and electricity self-consumption.”
10. United Kingdom – 2.9 GW – Rewind 5 years ago and the UK was miles away from being in the top 10. Improvements in the efficiency of the tech teamed with good government backing means that the UK has become a poster child for the global solar boom.
The world we live in today is driven by how much energy we have. For example when oil prices are high, we drive less and complain about all the things wrong with oil supply. When oil prices are low, we drive more and tend to forget about the core problem. The problem is not that there isn’t enough oil in the world or where it comes from, it’s how we go about energy production. There is no doubt that energy produced from coal and oil is “dirty” but it does have it’s perks. Traditional means of energy production (petroleum and coal) have been in use for a while now so the infrastructure is already there and its technology is well known. Petroleum and coal resources are abundantly found and the power produced from these plants is highly reliable. The same can’t be said for most forms of renewable energy. Renewable energy resources like solar and wind power, although very clean for the environment, have a few major hurdles to overcome if they are ever to be mainstream. A VERY long post can be made about how energy production, both on a national scale and a global scale, can be changed to better the environment and strengthen global ties but that’s not my plan. I simply want to share the pros and cons of each renewable resource and share why they aren’t currently taking the place of traditional energy production methods.
Renewable energy is diffuse, meaning low energy content per unit area and time. This is mainly due to the resources being in variable supply. You may be thinking: How is renewable energy variable? Well, take sunlight for example. The sun rises and sets in a full day. Energy from the sun can only be used when it’s out and most efficiently, when the suns rays are collected perpendicular to the surface of the solar panel. When the sun light fades out for the day, that’s it! Makes sense since solar collectors only work when there’s sun light to collect. At night, the solar plant no longer has its resource available unlike the coal or oil plant across town which can continue to generate power long after the sun sets. Now, a solar plant can store thermal energy from the sun’s rays but it can be unpractical or too costly to do so. Let’s take a closer look at individual renewable resources and the pros and cons associated with each one.
Solar Energy
Simple Solar Grid. Photo Credit: solarpowernotes.com
Pros:
– Large resource (any incident light that passes through the Earths atmosphere can be used for energy production!) – Minimal pollution (sunlight can be used directly for electricity or as a thermal resource) -Free! (Power plants don’t have to “BUY” sunlight)
Cons:
– Diffuse – Cyclical (Can cause fluctuating thermal stresses in components) – Not dependable (Sun goes down = no more resource) – Design for high temperatures (Sun collectors need to handle the high temps of the solar irradiance) – Storage (Electricity can be stored in batteries or heat can be stored in salt thermal pools) – Concentrated Thermal Pollution (Higher temperature levels concentrated in a single area) – Land use (collectors and receiver efficiencies range from 40-70% so many are needed to make the plant worth it)
Pros:
– Long Lasting (As long as there’s rain and moving water the plant can generate power) – Low temperatures (No thermal cycles needed as it uses the energy of falling water to spin a turbine/generator) – High efficiency (Converts work (falling water) to work (rotating turbine) which is the most efficient conversion possible) – Cheap! (All it takes is a dam, a powerhouse (with a turbine and generator), and pipes!) – Reliable (Water can be stored behind a dam for long running times even through droughts)
Cons:
– Habitat loss (Animals can be forced out of their homes to build a site) – Nutrient loss (Nutrients needed downstream for plants and animals can be blocked upstream by the dam)
Wind Power
Wind Power Plant Layout. Photo Credit: yokogawa.com
Pros:
– Free! (No resource cost) – Low operating cost (No thermal cycles; similar work to work conversion found in Hydropower) – Huge resource (Wind is generated by a number of mechanisms making it abundant everywhere)
Cons:
– High capital cost (Huge Turbines = Huge Cost; machinery is large and over designed pushing cost high) – Visual pollution (Usually located by mountains and deserts, wind power plants can take away from nature’s beauty) – Noise pollution (Each passing blade produces a buffeting noise that make living near one hard) – Bird Kills (Birds often times don’t see the blades of wind turbines) – Land usage (Like solar energy, a lot of land is needed to make the plant worth it)
Biomass
Biomass Resources. Photo Credit: energy.ca.gov
Pros:
– Large Supply (literally anything can be used: plants, animals, wood, sugar cane, kelp, menure, sewage, waste, etc) – Efficient use of byproducts (Nutrient rich byproducts are left over from this process which can be re-fed to starting point) – Low pollution (low levels of carbon dioxide gas) – Cheap supply cost (example: the old grease from the fast food place down the street can be used)
Cons:
– Soil depletion and erosion (Compostables once used for fertilizing are now used for energy production) – Competes with food/feed growing (Land and resources are split between food and products used in energy production) – Bulky (Transportation of waste and resources must be considered)
There is certainly enough renewable resources out there with many of them being able to provide for the worlds energy needs on their own. The problem, as I hope I showed here, is that many design issues must be tackled before moving away from traditional fuels. There is no overnight solution and there won’t be one for little while. Some of the cleaner processes pollute less than oil but physically harm the earth they sit on. Others are just too theoretically perfect to be implemented in real life. If you want my full view on how we can tackle this energy production problem let me know…I wrote a paper!
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F/A-18F Super Hornet at high angle of attack over a snowy mountain range. Photo Credit: navy-pictures.blogspot.com
Let’s start off with a scenario: You’re flying a sortie for the Navy in a reconnaissance-configured F/A-18F Super Hornet to fly in high over some mountain range in Afghanistan, take some pictures, and come home. You’re flying at 40,000 ft in order to both stay clear of the immensely tall mountain ranges and to remain undetectable and stay out of reach of small arms fire. Unfortunately, at 40,000 ft in this region, icing conditions are very common. Due to the low temperatures in this region (and especially at this elevation) combined with the all-too-often rainy or snowy conditions, you end up having to fly through falling snow or rain (which would be either already ice due to the low temperatures, or supercooled, meaning that the water drops are far below the freezing point, but have not frozen yet due to the absence of a nucleation site – which is essentially a solid surface on which the water can freeze…i.e. dust, other particulate matter, or the wing of an aircraft).
As you begin to fly into the poor weather, the water droplets begin to freeze on impact with the wing, building up a layer of ice on the wing of your aircraft. This ice quickly changes the surface roughness of your aircraft wings, changing the aerodynamics and lowering the speed or angle of attack that you can travel at without stalling (flow separation that leads to loss of lift). Furthermore, say due to the angle of incidence between your flight path and the direction the water droplets are coming from, the ice is forming more heavily on one side/wing of your aircraft than the other (and probably unevenly on each side). You start to feel the aircraft wobbling around in flight and find it much more difficult to control your roll, pitch, and yaw. You are now having issues flying the aircraft at the required speed, are having to fly at a lower angle of attack, and are having trouble controlling the aircraft. You have a decision to make: continue to put yourself, your Radar Intercept Officer (RIO), and your $60,000,000 aircraft in danger or abort the mission. Unfortunately, this situation is not too uncommon when icing presents a real problem to pilots.
With the development of unmanned drones for reconnaissance missions, we are able to push the envelope a little more, but still are wary of putting a very expensive aircraft into poor weather conditions (for both financial losses and the possibility of having a high-tech aircraft downed in enemy territory). This problem also exists for civilian air travel, and in many cases, general aviation pilots are not certified for flight into known icing conditions due to the clear and present danger. So what do we do to reduce the threat posed by icing conditions?
Aircraft wing icing and an expandable rubber boot used to break up the ice. Photo Credit: cloudman23.files.wordpress.com
There are a few traditional ways of dealing with aircraft icing. One is shown above, in which a rubber “boot” is expanded in order to break up the ice on the leading edge of the aircraft; obviously, this is not an optimal solution, as it temporarily changes the profile of the wing, and also does not get rid of all of the ice. Other methods include bleeding hot engine exhaust air over the wing and using “weeping” wings that release antifreeze over the surface of the wing, to name a few. These methods are all quite complex, require a lot of power, can alter the airflow significantly, and may even present environmental dangers (as in the case of the weeping wing).
In order to fill this void of optimal solutions, a company called Batelle has employed its researchers to develop a solution that consists of a carbon nano-tube coating that can be included beneath the topcoat of the aircraft wing and then act as a resistance heater of sorts to warm the wing from inside the wing to prevent or get rid of ice on the wings. This solution employs advanced materials science concepts in order to introduce a more elegant, non-invasive means of dealing with aircraft icing. Furthermore, the coating is controlled through an “intelligent controller [that] monitors the heater performance and applies only the power levels required for the flight conditions”, making it less power-hungry and more adaptable to any given situation! These benefits are realized even further on military Unmanned Aerial Vehicles (UAVs) (their principal application), where large sensor (or other) payload power requirements and desired lightweight dictate that a smaller than ordinary amount of power can be dedicated to de-icing. This solution has the capability to revolutionize the way we go about preventing or dealing with aircraft icing; now only if they could further development this solution for use in the de-icing of pitot tubes (devices used to measure airspeed – to figure out how fast you are flying; pitot tubes are notorious for encountering problems in icing conditions, where a false airspeed reading can lead to disaster).
I approached this Open Mind a little differently from my latest round of posts. Instead of developing ideas and solutions over the course of a month, I gave myself a “pop” design challenge. The topic: If you were the lead designer for a new NASA Telescope, what considerations would be most important to you? My goal: Instead of developing the best or most important considerations for this challenge, I would develop the first three considerations that popped into my head.
My first thought dealt with finances. As the project manager, I would need to know how much funding the team has and what it will be used for. To me, the days of dumping money into a project especially for exploration are far and few between. It’s unfortunate but there are companies out there that are reviving the passion for space and underwater exploration; our team included. In order to justify spending money on a new exploration project, the team will absolutely have to design intelligently. By using sustainable materials and avoiding “reinventing the wheel”, the design team can focus on improving technology already available thus potentially saving money.
The second thought to pop up was about the project’s overall life cycle. As a manager, I would need to establish an efficient way to not only start and end the project, but see if the telescope has life after decommission. Can anything off the telescope be used or recycled after it’s no longer needed? There’s more to “design” now than ever since there’s a push to go green in all industries. Anything from control systems to frame material can be inspected and potentially approved for reuse. These parts don’t have to be used for serious missions but can be utilized in testing scenarios or for higher education.
The final thought before I called time revolved around power generation. Fuel supply and consumption are always design concerns for any project but none more than in space/underwater applications. There are particles of various sizes translating across space. If a designer can harness the power of small impacts on the telescope by the particles or generate rotational motion from the moving particles, power can be generated. This power can be used to charge batteries in times of need.
Well there you have it, an expedited Open Mind that took place in less than one minute. Take a look at other Team UV Open Minds from previous months and don’t forget to support our GoFundMe site!
Stress concentration around a hole visualized using photoelastic methods, with strain gages attached to the surface to measure strain, which can be back-converted to find the state of stress. Photo Credit: alliance.seas.upenn.edu
Stress concentrations (commonly referred to as stress risers or raisers) are areas in a material that, owing to problematic geometry, lead to…well, greater stress concentration in portions of the material/part. These concentrations can be great headaches to engineers, as the localized concentration of the stress means the part experiences much higher stresses in said specific regions than the average stress in the material as a whole (or than the material would experience without the riser), which can lead to failure at much smaller loadings than originally thought. Well what in the world does that mean?
To better explain this, we will examine a very simple case: pure tension in a rectangular sample. Imagine that you take a rectangular bar and pull on it along it’s axis, as shown below. We will make some simplifying assumptions for the purpose of ease of demonstration; assume that when you pull on the sample, you pull on the entire end face equally; that is, you distribute the loading across the entire face equally. Also assume that the material is homogenous (the same physical & mechanical properties at all points throughout the material), isotropic (the same properties in all directions), and uniform in cross-section. These assumptions will hold for demonstration and are sometimes used in applications in which strength is not of major concern, but generally speaking, it will be very difficult to apply a load evenly across a surface (picture gripping a piece of metal with a pair of pliers…the grip point is the point of load application and does not cover the entire face, but rather is localized), materials will never be homogenous (due to voids, inclusions, and other manufacturing defects), many materials will not be isotropic (a piece of un-altered steel is isotropic, but wood, for example, has directional strength in the directions of its “grains”; many other materials also express different properties in different directions), and many geometries will betray the assumption of uniform cross section (as we will see shortly).
Simple case of pure tension. Photo Credit: Wikipedia.org
When we pull on the material, that force is transmitted through the material with an equal and opposite reaction internal to the material, as shown in the center image of the above picture. This force may be shown as a single resultant force vector (like in the center image), but is actually distributed over the entire inside of the material (as shown in the right/3rd image). When this load/force acts over this area (and remember, we are only looking at pure tension…the load is applied perfectly perpendicular to the material cross section, as otherwise we would induce bending), it creates a normal stress that is defined as the applied load divided by the cross-sectional area. Under the assumptions we made before, this should mean that every point in the material experiences the same normal stress, meaning that in order for the material to fail, the average normal stress in the material needs to exceed the failure strength (in this case, the applicable tensile strength).
But what happens when we apply a stress concentration, by introducing a discontinuity in the geometry (i.e. a crack, sharp edge/corner, or change in cross-sectional area)? The stress distribution can no longer be uniform, as the loading has to be re-routed to avoid the discontinuity as it travels through the material (for the case of geometric stress concentration), as shown for the simple case of a circular hole in the material below.
Effect of geometric discontinuity on stress distribution. Photo Credit: Wikipedia.org
As can be seen, the distribution tends to bunch up around the hole, creating a higher concentration of stress. From a mathematical standpoint, the local normal stress in the region of the hole has also decreased as the cross-sectional area of the sample at the hole location is now less (imagine cutting the bar in half perpendicular to the loading and looking at it from the end…instead of being the full rectangular cross-section of before, there is material missing), thus the normal stress is higher because we are applying the same load, but now are dividing it by a smaller area than before. This means that if we apply a loading to the uniform sample that created a stress under the tensile strength of the material before, that materials would not fail, but now if we apply the same exact loading to this new sample with the stress riser, the sample could very well fail due to the heightened stress at the discontinuity. This should be seen as quite alarming as this means that parts can fail at lower loadings than expected, and while our example shows a huge hole in the part, it should be noted that small cracks, or simpler sharp corners and other minimal, yet abrupt changes in the geometry can affect the state of stress in a major way.
Effect of geometric discontinuities on stress distribution. Photo Credit: teachengineering.org
We should also note that highly concentrated stress regions can be formed by applying loads non-uniformly, as in the example of gripping material with pliers discussed in the 2nd paragraph, where we apply a load on a very localized, concentrated region (picture taking a 10 lb weight and placing it directly on a table vs. taking the same weight, balancing it on a thumbtack, and then placing it on the table with the tack point down). Just as before, we have decreased the effective are that the load is applied over, except this time, we reduced the area of the stress region by changing how the load was applied, whereas before we did it by changing how the load was transmitted.
Exaggerated demonstration of effect of concentrated loading on stress distribution. Photo Credit: mace.manchester.ac.uk
For this reason, engineers must be very careful when they design parts to include factors of safety to account for material imperfections, possibly use non-destructive inspection (NDI) techniques to examine critical parts for cracks in situations where a crack could prove catastrophic (for example a crack in the side wall of a submarine hull that could spread due to cyclic fatigue due to cycles of compression/de-compression when traversing great depths, surfacing, sinking again, surfacing again, etc.), and must avoid abrupt changes in geometry in the design of the part itself. Luckily, in this day and age, we understand much more about internal stresses and stress distribution thanks to new testings and stress visualization techniques, but the subject of stress concentrations is one that I cannot stress the importance of enough! (I apologize for the bad pun)
Effect of rounding sharp corners using “fillets” on stress concentration. Photo Credit: corrosionpedia.com
Additionally, this was purely looking at one-dimensional loading in an over-simplified material and geometry, but in the real world we can have parts of really intricate geometry, made from materials with unbelievable amounts of anisotropy (different properties in different directions), subjected to combined three-dimensional loading of tension, bending, torsion, shear, perhaps compression in a different region, with hygrothermal loading (loading due to both moisture and thermal effects), subjected to different kinds of corrosion, vibrational modes, impact loading, and the list just goes on and on! Anyways, hopefully today you learned a little bit more about one of the endless topics that engineering encompasses! I will leave you with some really cool photoelastic stress visualization pictures in which the refraction of light is a function of stress (due to birefringence), thus the material essentially shows different wavelengths (and thus different colors) due to differences in stress throughout the material, helping to visualize stress (and stress concentrations).
Stress concentration at a sharp corner in a plastic protractor (Photoelastic visualization). Photo Credit: Wikipedia.org
Photoelastic visualization of stress distribution in plastic eating utensils. Photo Credit: flickr.com/photos/chrisar/ (Christian Rein)
Photoelastic visualization of contact stresses on a marble in a C-clamp. Photo Credit: osa-opn.org
Photoelastic visualization of rolling contact stresses due to a cylinder rolling on a flat surface; the cylinder is rolling to the left. Photo Credit: Wikipedia.org
Steel is the foundation of the modern structure, be it buildings, airplanes, or ships. Plain carbon steel is a simple mixture of carbon and iron in just the right proportion to provide excellent strength. As humans have taken to the sky lighter materials have been required. This has led to dominance of aluminum, titanium, and composite materials for weight savings. These materials are stronger per unit weight than steel but more expensive and less plentiful. Scientists have just recently discovered a new steel alloy that provides the strength to weight ratio of titanium using much more available materials. This could lead to a revolution in the structural steel world, but for now they need to find a way to manufacture it outside of a lab setting. Read more here: http://www.gizmag.com/steel-alloy-strong-light-titanium/35996/
Plateau-Rayleigh Instability in a water sheet from a fountain. Photo Credit: f***yeahfluiddynamics.tumblr.com
Here at TeamUV.org, we have often discussed some of the finer intricacies of fluid mechanics (or usually more specifically, fluid dynamics, as opposed to fluid statics). Generally speaking, however, we have looked at fluid flow and behavior from a very macroscopic view, that is we have looked at fluids as they act on the macroscopic length scale, within which objects are practically visible by the naked eye. In the various fields of engineering, most engineers would only need a macroscopic understanding of fluid mechanics in order to perform rather rudimentary calculations and analysis. For example, if an engineer was asked to determine the hydrostatic pressure exerted on a submerged pressure vessel lying on the bottom of the ocean or if they were asked to size (determine pump impeller diameter, pump speed, power input necessary, pump type, capacity/flow rate, etc. for) a pump based off of the known pressure gradient (perhaps it has to force water through a very fine filter while maintaining a certain amount of pressure), elevation change, or required change in speed, a macroscopic view of fluid mechanics would often be sufficient. But is this always the case?
Of course not! The golden rule of engineering regarding what you need to know to perform your job is that there is no golden rule of engineering regarding what you need to know to perform your job. Engineering is a highly dynamic field, with ground-breaking discoveries made continuously…right now, somewhere in the world a scientist or engineer is making a major contribution to the future of STEM. Additionally, engineers (especially mechanical engineers, who have a very large, diverse knowledge base) can be asked to do anything at any given time, and they must be able to figure it out! So to say that the macro scale is the only one an engineer needs to be aware of (especially in the field of fluid mechanics) would be a gross understatement. So where does that leave us? Well now would be a good time to explain what is meant by “length scale” and to share some of the typical ones. After that, we will very briefly roll through some of the fluid effects that exist on smaller length scales, as these highly complex phenomena are beyond the scope of this post.
Orders of magnitude as they apply to the Eiffel Tower viewed from different length scales, demonstrating how different length scales reveal different details. Photo Credit: iupui.edu
A length scale is essentially a parameter for deciphering the characteristic length associated with a phenomena. For example, if we are talking about the atomic scale, we are generally talking about phenomena that occurs in the size range of atoms, on the order of magnitude of pico- to femto-meters (10^-12 or ^-15 m). If we are talking about the microscale, we are talking about things on the order of micrometers (10^-6 m) such as water droplets or the thickness of a human hair. The macroscale would be associated with cars, mountains, you and I, etc. and would be essentially anything in your field of vision, i.e. probably from millimeters on up to kilometers (although the macroscale is not precisely defined). From here, we would likely move on to the astronomic scale, which is generally used to refer to phenomena on the scale of the universe, or Megameters (10^6 or 1,000,000 m) on up. For example, if you were to move from an atomic to micro to macro to larger with regards to your hand, you could envision protons and neutrons in your skin cells and then zoom out to bacteria under a microscope and then zoom out further to your hand itself and then zoom out further to the Earth itself, further to the Milky Way Galaxy, and so on and so on. In fact, if you have a second, you should check out this zoomable tool for visualizing the scales of the universe.
So back to fluid dynamics after a very lengthy detour, why should we care about length scales smaller than the macroscale? Because turbulence (as well as all fluid motion and other physical phenomena in general), is a result of phenomena on smaller length scales. So in order to actually understand the onset of turbulence or how fluids react with each other or with structures, etc. within the framework of deeper understanding, we must understand the microscopic behavior of fluids. Much of this behavior is defined by fluid stability and instabilities, which are not only very interesting to look at, but are the building blocks for the entire field of fluid dynamics as we know it! At this point, I will quickly show some pictures of some of the more common instabilities, but will not go into descriptive detail as scientifically, mathematically, etc. they are extremely complex phenomena that many fluid dynamicists spend their entire careers studying.
Note: Due to miscommunication, this post was submitted late and thus scheduled late; rest assured, regular scheduling will resume on Sunday.
Back at my parent’s house in North County San Diego we have a lot of olive trees and every year they drop their fruit on the ground and make quite a mess. There is no sense in letting all of these olives go to waste so I looked into ways to turn them into a usable oil. It was surprisingly simple, just follow a few steps.
First the harvest. The olives are pretty small and there are a lot of them all over the tree making it way too labor intensive to pick by hand. The simplest way to do it is to lay a tarp on the ground, get a ladder and comb the branches with a garden fork or rake. Let the olives and leaves fall on the tarp then collect them all and pick the olives out.
Now that you’ve got a good amount of olives you’ve got to get the oil out of them. This is where industrial manufacturers use massive hammer mills and centrifuges. That’s a bit of an overkill for home production. First you need to crush the olives, to do this you can just get a strong bag, fill it with olives and go at it with a hammer. I tried a meat grinder and it worked OK but the pits jammed up the machine, a bag and hammer wont have that problem!
Once you have a pretty good pulp of olives you’ve got to mix them so that the oil can form large enough droplets to be pressed out. Don’t mix for much longer than 15 min because you’re adding oxygen to the oil and that will give it an undesirable flavor and color, but if you mix much less than that the oil won’t form large enough droplets.
Now for the pressing. It takes quite a lot of pressure to get the most out of this olive paste so I got a 20 ton bottle jack for a car, built a frame with a two plates and used the jack to press the olives. First spread the paste on burlap or cheese cloth, really any porous fabric that will allow the solids to stay in place and the liquids to flow. Then fold up the cloth, put it in the press and press. Collect all the liquid that comes out and pour it into bottles.
The liquid in the bottles will be about 90% water and 10% olive oil. Leave these bottles in a cool dark place for several weeks to give the oil plenty of time to settle out then pour off the oil on top and store for later, or enjoy now. It will taste very different from store bought oil, in a great way!
Boiled eggs are delicious, I’m pretty sure no one will object to that, but have you ever thought of unboiling eggs? A group of chemists out of UC Irvine and Australia have made this discovery which has the potential to change the biotechnology industry and dramatically reduce the time and cost for production of cancer treatments among other applications!
Now this wasn’t done simply for the sake of unboiling eggs, it was used to demonstrate how powerful this new technique of returning tangled proteins to their original form really is. Proteins are made of chains of amino acids that are folded and arranged in a specific way. Changes in pH and/or temperature disrupt the bonds holding the proteins in their original shape causing it to deform and tangle. So when you cook an egg you are actually tangling proteins which causes them to change from clear to white. The process is known as denaturation and is problematic for scientists who are trying to recycle valuable proteins after use. Previous methods of solving this issue exist but they are time consuming and expensive. This new process, however, gives results in minutes.
Professor Colin Raston’s vortex fluid device. Photo Credit: WashingtonPost.com
In the findings published in ChemBioChem, egg-whites were first boiled for 20 minutes at 90 degrees Celsius (194 deg. F) (plenty of time to tangle the delicious proteins). To revert a protein in the cooked eggs called lysozyme, urea was added to liquefy the solid whites. The resulting substance was then placed in a vortex fluid device which is a high powered machine designed by Professor Colin Raston’s laboratory at South Australia’s Flinders University. This machine applied shear stress to the proteins which encouraged them to untangle and re-fold to their original form.
There is huge potential for this discovery that can streamline protein manufacturing and make cancer treatments more affordable. Think about this next time you’re making omelets. For more information on the findings please visit http://onlinelibrary.wiley.com/doi/10.1002/cbic.201402427/abstract
Rock climbing is becoming more and more popular as gyms pop up all over Southern California. This sport, like all sports, has many components that have been analyzed and optimized by engineers. Rock climbing brings its own unique challenges, most of all the balance between safety and weight. The more safety gear a climber uses the heavier they are and the more likely they will get tired and make a crucial mistake.
Climbing ropes are the major staple for safety gear. A climbing rope must be strong enough to catch a falling climber, tough enough to withstand almost constant rubbing against rough rocks, and still stretch enough so that the climber isn’t injured by a quick stop from a long fall. This is quite a bill for any rope to withstand but climbing rope does the job incredibly well. For a class project, standard nylon rock climbing rope was tested and compared to nylon 550 paracord and standard polypropylene utility rope. The differences were very apparent. While the paracord and utility rope broke fairly easily the climbing rope withstood more weight and stretched beyond the range of the testing machine. Try as we might we could not break the climbing rope within the range of motion that we had. This rope had a few interesting properties that led to its great success. First there was a protective casing of a tough material that could resist abrasion very well, then within, in the load carrying section the fibers had a special weave. This weave allowed the rope to stretch very far without breaking and slowly load the fibers that made up the rope. Some engineer did their job very well.
The very act of rock climbing can be helped by a brief engineering analysis. First off is conservation of energy. A climber’s muscles have a limited amount of energy in them so that energy needs to be saved for actual motion on the rock. When a climber is hanging on the rock, looking for the next hold or clipping in the rope their arms are fully extended allowing the weight of their bodies to be held by their bones, a rigid structure, rather than their muscles, an energy devouring structure. Another concept is as simple as balance, when a climber can just hang on a rock rather than resist swing or spin they are in a low energy state, even if this means that they are horizontal to the ground. A trick for this is being aware of your own center of mass as a climber and ensuring that it is perpendicular to the hold surface.
The more a climber can think about the physics of climbing the more energy they will be able to conserve and the better technique they will have.
Mechanics of an airplane in flight. Photo Credit: av8n.com
Update on technical issues: issues have been fixed, regular posting will resume tomorrow (Sunday).
Turning is also tricky business. On airplanes, aerodynamic forces can be broken down into two components: drag and lift. Lift is a two dimensional vector in the plane (geometrically speaking, not to be confused with a physical airplane) perpendicular to the direction of relative wind, however in “normal flight” we can make the assumption that lift is in the direction of perpendicular to the relative wind and wing span as seen above. Basically we can assume all these forces are happening in a single plane. Weight is mass times local gravitational acceleration (which can/will change during flight). Thrust is a force produced by the engine that is in direction along the axis of the engine. This is especially important if your engine is right smack dab in the middle of your vehicle…
Only when you’re flying straight, level, at a constant speed, constant altitude, and through still air can you assume thrust+drag=0 and lift+weight=0. So pretty much in any other case there are forces going on all kinds of crazy directions in three dimensional space.
Non-intuitively, lift is less then weight in two situations: high power nose climb and low power down decent. Sounds paradoxical but in fact thrust takes up some weight in climb and drag takes up some weight in decent. Force balance, it helps.
Any who, why do we even care about these forces? Well during normal flying (sounds weird to say because I don’t consider flying normal) we don’t, except during a turn. During a banked turn the lift vector is inclined out of the plane (geometric) of the image above, so in order to pull the airplane around the turn and keep it at that altitude, the lift vector must be significantly greater than the weight. So the lift vector can be summarized into two components during a turn: a vertical component to oppose lift and a horizontal component to change direction in which the airplane is flying.
Let’s start simple. Boat turns are relatively simple because they neither have to fly or dive. A flying boat would be pretty cool though…but I digress. Say you want to make a right turn, in the figure below, turning the rudder to the right will cause the boat to yaw starboard. Relative wind will hit the port side of the boat and create tremendous drag which will incidentally turn the boat to the right. The force on the rudder by the wind is smaller than the force of the wind of the portside of the boat which means turning. Now apply all this to airplanes and you have a simple boat turn on an airplane. This sounds great and all, however, turning the airplane properly by using the wings is way more effective and efficient than boat turning. There is also a lot more going on during banked turning as well.
Boat turn. Photo Credit: av8n.com
Airplane turn. Photo Credit: av8n.com
When using your wings to turn, there is a tendency to overbank which basically means overturning. As seen in the figure below, the distance the inside wingtip has to travel is smaller than the outside wingtip and since the outside wing is traveling farther in the same amount time, it must be moving faster.
The lift generated by airfoils depends on the square of airspeed, so the outside wing will be producing more lift which leads to overbanking which leads to a spiral dive into oblivion. Luckily for us, this effect depends on the ratio of wingspan to the radius of turn. For stubby wings, high airspeed, and shallow bank angle, you’ll never notice the effect. For a glider however, you need to deflect the ailerons against the turn to create an opposing force. And to make things even more convoluted, to counteract something called long-tail slip effect, you will be holding your rudder into the turn. So your controls seem like a paradox at this point but this will mean a much better turn then a simple boat turn. Long-tail slip effect is a topic for another day, but if you’re an aspiring pilot or you just want to learn more, please visit http://www.av8n.com/how/#contents for more of your aerodynamic needs.
Panasonic’s photocatalytic water purification system. Photo Credit: wonderfulengineering.com
Note: Our apologizes for the missed post on Tuesday; we had some technical difficulties and so have posted the original Tuesday post (this post) for today and will be posting the original Thursday post tomorrow (Friday 1000 hours) instead. Regular scheduling will resume on Sunday.
In some parts of the world clean drinking water is quite rare as the water sources are polluted and purification methods are not available. Panasonic is developing a new technology to address this problem. This technology uses the sunlight for purification of the water extracted from the ground. Recently, a system was presented by the company that uses photocatalysts and sunlight to purify water at a high reaction speed. This readily improves access to clean water, in areas where needed.
The recent breakthrough that led to the discovery of this technology is the system’s ability to bind titanium dioxide (TiO2), a photocatalyst capable to react under ultraviolet light. TiO2 comes in super fine particles and is hard to collect once it has dispersed in the water. Previously, other larger materials were used to bind the TiO2 to them, but it was a loss of active site surface area. The way this technology by Panasonic differs from those found before, is the discovery of Zeolite particles’ (a commercial adsorbent and catalyst) ability to bind the TiO2 particles. This solves the problem by enabling photocatalysts to maintain their active site. As the two particles are bound together by electrostatic force, there is no need for the binder chemicals. As the new photocatalytic particles are stirred, the Zeolite releases the TiO2, which then disperses throughout the water. The resultant reaction speed is much faster as compared to other methods and the processing of large amounts of water is supported. The TiO2 binds to the Zeolite again if the water is still left, which makes it easy to separate and recover the photocatalysts from the water for later use.
The main idea of this project is to develop a small-scale version of this purification system, which may then be deployed at different places where purification of water is needed. See how the system works below!
Panasonic’s photocatalytic water purification system process diagram. Photo Credit: wonderfulengineering.com
Prompt: Mechanical engineering is inherently ambiguous to those without an intimate knowledge of its principles. As mechanical engineering students, there is an excellent chance that most of the people you know believe that your job consists of working on cars, acting in the role of a technician, or some related role. Even people from many other engineering disciplines rarely know exactly what we study or what we do. None of these people are to blame; rather, this is simply a consequence of the fact that the only people who take (many) actual mechanical engineering classes are mechanical engineers (/mechanical engineering students). When a person grows up and moves along through the educational system, they take classes in History, Mathematics, Literature, Biology, Chemistry, Art, etc., and perhaps even Physics, but they never take any sort of engineering class unless that is the career path they choose to follow. As a result, many people who could have possibly unearthed a deep love for engineering never received the chance to do so. In recent years, many K-12 schools have been moving to fix this and have been especially working to expose traditionally-underrepresented student groups to the world of engineering at an early age. Come up with either 3 ideas (or one idea from 3 perspectives) to help spread awareness with regards to the existence of the world of engineering (more specifically, mechanical engineering) to people at a younger age, thus hypothesizing as to how we can help more possible future (mechanical) engineers discover their ambitions.
“Ownbot” a robot created by engineering students from Victoria University of Wellington (New Zealand). Photo Credit: victoria.ac.nz
It’s true. When I say that I’m studying mechanical engineering, people think I work on cars or I’m learning to work on cars. Even after explaining what I actually learn in my classes, most people stop listening after about ten seconds and conclude that just I’m a “fancy” mechanic. Not the case. When I was as freshman in high school I had no idea what engineering was. All I heard was that it involved a lot of math and it was not for everyone. I agree with both statements but the latter I think overstated. How can you decide something is not right for you if you don’t even know what it is? This is why I’ve come up with three ways to spread awareness of the world of engineering.
1) Teach team oriented problem solving, systematic reasoning, and creative problem solving at a young age. I feel too many kids do not know how to work together effectively or know how to logically solve a problem they’ve never faced before. I was with my thirteen year old cousin recently and asked him to set up a music stand for me while I got everything else ready. There were three pieces to the stand and after 30 seconds of trying he said it was broken. It clearly wasn’t. Now I’m not saying he’s “dumb” but he had no idea how to logically figure out how to solve this problem. He just simply tried one thing, it didn’t work, and decided it was must be broken. That is not the kind of world I want to live in which is why these kinds of things should be taught much earlier. Even if you have no idea how to solve something, there are creative, logical, and scientific steps you can take to better understand what is going on. MIT has developed programs like Scratch to teach these ideas to kids through basic programming. http://scratch.mit.edu/
2) Presentations Now I’m not saying a thorough and extensive lecture on PID control to 5th graders, but a very well polished presentation on how cool engineering can be. I think people have to be exposed to a more visual representation of what an engineer actually does instead of rumors and hear-say. I’m sure 10 year old Abe would have been incredibly impressed and inspired if he saw an underwater vehicle designed and created by students at the local university. How all these engineering principles came together into something that he could touch and see move around a pool so swiftly and majestically. A really good presentation can make the word “engineer” seem not so scary for an entire generation.
3) Engineering Competitions I think recently more schools have gotten into engineering competitions. There’s high school solar boat, elementary school robot programming, and even model bridge building competitions. These are incredibly fun because most of these projects are in collaboration with engineering programs at universities so young minds can really get into the engineering mindset through a mentor. I did solar boat and it was one of the most fulfilling things I did at Warren High. If I wasn’t a part of it then and there I probably wouldn’t have chosen mechanical engineering as my major so I definitely encourage more of these types of competitions.
Overall there has been a bigger push to teach kids how to do things they could never do before. Building, problem solving, and working together. They are all a big part of engineering but of life also. In today’s 21st century I don’t think you can progress without these skills so I’m glad that I learned them in the classroom. Hopefully in the coming years more people will realize how important and interesting the field of engineering really is.
Swiss Federal Institute of Technology Sepios robot. Photo Credit: engadget.com
Team UV is not the only one who has an interest in underwater technology! The latest in underwater robotics has taken inspiration from the undulating motion of the cuttlefish, rather than conventional methods such as propellers and solid fins. Previous attempts at fish like robotics have produced decent mimics of fish motion, however, they have always been rather limited in terms of agility and precision. Researchers form Swiss Federal Institute of Technology (ETH) in Zurich are set to change this thought with their four finned cuttlefish inspired Sepios robot. Sepios carries a 20,000mAh battery, which is good for as much as 90 minutes of dive time with a top speed of 1.8 km per hour (~1.12 mph or 1.64 ft/s). The current version is only rated for use at depths up to 10 meters (~32.8 ft), which is plenty to explore coastal waters and film wildlife.
Sepios can see effortlessly through a forest of seagrass, even in stormy conditions. Each fin can be controlled separately allowing the robot to move in any direction with ease. The team is now working on improving the coordination of its many sensors, for example pressure and humidity detectors and an on-board camera, laser and inertial measurement unit that help it avoid collisions.
Maybe Sepios will be swimming with Team UV’s underwater vehicle in the future! 🙂
The US Navy, specifically the Office of Naval Research, recently released information about their latest protection technology for their own fleet. They have employed smaller autonomous boats, called Swarmboats, that swarm and intercept threats in order to protect the larger Navy ships. Smaller, faster, and more nimble boats are fitted with a system called CARACas which stands for Control Architecture for Robotic Agent Command and Sensing. To make this system as modular as possible, engineers have designed their control systems to be as “plug and play” as possible, allowing any boat to be retrofitted. Initial testing showed that up to 13 Swarmboats can be linked up to protect a “mother” ship. Right now the protection boats are used to detect and deter but have the capabilities to destroy upon command!
13 of our senior project vehicles all synced up under water? Drool…
The motivation behind such a project was the terrible attack on USS Cole in 2000. A small enemy boat filled with explosives simply approached the ship and killed 17 sailors and injured many others. Swarmboats could have easily intercepted the enemy boat and prevented it from coming within deadly range.
Rolex is a universe of its own: respected, admired, valued, and known across the globe. Rolex does just make watches and their timepieces have taken on a role beyond that of mere timekeeper. Having said that, the reason a “Rolex is a Rolex” is because they are good watches and tell pretty good time. There is a very real mystique behind the manufacture because they are relatively closed and their operations aren’t public. The brand takes the concept of Swiss discreetness to a new level, and in a lot of ways that is good for them. Here is a list of why Rolexes are so expensive.
1. They use an expensive and difficult to machine steel because it looks better. Most steel watches are make from a common 316L stainless steel. However, Rolex watches are made from 904L steel. 904L steel is more rust and corrosion resistant, and is somewhat harder than other steels. 904L steel, when worked properly, is able to take and hold polishes incredibly well.
2. Their movements are all hand-assembled and tested. Rolex watches are given all the hands-on human attention you’d like to expect from a fine Swiss made watch. Rolex uses machines for the process sure, but everything from Rolex movements to bracelets are assembled by hand.
3. An in-house foundry makes all their gold. Rolex makes their own gold. 24k gold comes into Rolex and it is turned into 18k yellow, white, or Rolex’s Everose gold. Large kilns under hot flames are used to melt and mix the metals which are then turned into cases and bracelets. Because Rolex controls the production and machining of their gold, they are able to strictly ensure not only quality, but the best looking parts.
4. Rolex Dive watches are each individually tested in pressurized tanks with water. All Rolex Oyster case watches are thoroughly tested for water resistance. The way that this is often done at watch manufactures is with an air-pressure tank. A watch is placed in a small chamber that is filled with air, and if the pressure changes at all, it means that air leaked into the case. Each Rolex Oyster, as well as Oyster dive watches begins with this air pressure treatment. In fact, each case is tested both before and after a movement and dial are placed inside of it. Dive watches receive a separate treatment all together. After being air pressure tested, Rolex proceeds to test the water resistance of each and every Rolex Submariner and Deep Sea watch in actual water. This type of test is much less common. Submariner watches are placed in large tubes that are filled with water to ensure that they are water resistant to 300 meters. The test is extremely complex because Rolex employs a complex system for testing if water entered the case. After the watches exit the tank, they are heated up and a drop of cold water is placed on the crystal to see if condensation forms. An optical sensor then scans them for trace amounts of water. Less than one in a thousand watches fail the test.
5. It takes about a year to make a Rolex watch. Rolex produces almost a million watches a year, but surprisingly, no shortcuts are taken in the manufacturing process. If you look at Rolex watches over time, they are more about evolution rather than revolution. This idea of always improving versus changing goes right into their manufacturing process as well. They are constantly learning how to improve quality through better processes and techniques. The move from aluminum to ceramic bezel inserts is a perfect example. Nevertheless, from starting to shape the parts of the case to testing a completed watch for accuracy, the process takes around one year. Of course Rolex could speed this up for certain models if necessary, but each watch requires so many parts and virtually everything is made from base materials in-house. Once all the parts for a Rolex watch are completed, they are then mostly hand-assembled and individually tested. The testing and quality assurance process is rather intense.
These are only a few reasons why they are so expensive and this should give you some insight into how much TLC Rolex puts in their watches! If you don’t believe me take a look at this video below of a Rolex being disassembled!
Stacked Shields on an Arduino. Photo Credit: robotshop.com
Arduino boards are very helpful and powerful tools to help connect the electronics world to the real world around us. Like I said in Part 1 of my Learning Arduino Series, they can read inputs and control outputs very quickly; faster than any human can do manually. With that said, an Arduino board, such as my handy UNO R3, can only do so much. After an “Arduinonian” has experimented with all the things in their beginners pack, they often want to venture out to more complex and demanding projects. Want to drive more than one motor? Want to drive two DC motors and 2-3 Servos? Want to connect your board to the internet or save data and images to an SD card? There’s a shield for that!
Robot Shield. Photo Credit: OpenElectronics
Shields are commonly made for microprocessors like the Arduino UNO R3 to inject it with extra functionality. They are designed to piggyback directly on top of your logic board, through the use of stacking headers, which can allow the use of pins not already in use by the shield itself. Some shields allow programmers to pull more amperage for driving bigger, hungrier motors while others add GPS or Bluetooth capabilities. There are WAY too many shields out there to describe in one post, so i will share with you some of the ones I have used and some that I plan to use in the near future.
1) Arduino Motor Shield R3
Arduino Motor Sheild. Photo Credit: Arduino.cc
The important thing about shields is that you want to make sure they are stackable with your specific board. For example this motor shield is called R3 because it fits perfectly on top of the UNO R3 but wouldn’t fit on the earlier R2. I bought this motor shield to do a few different projects that required me to use much stronger motors than the UNO R3 can handle. With the shield installed, a programmer can pull up to 4A, 2A per channel, safely with operating voltages up to 12V. It’s designed to drive relays, solenoids, DC motors, and stepper motors. In fact, it can drive two DC motors independently or one stepper motor with speed and direction control for either case. The shield can be powered by the same power supplied to the logic board (i.e UNO R3) or it can be powered by an external source through the VIN and GND terminals on the shield.
I found this shield to be very easy to use especially with everything already soldered on, even the headers. Working with the supplied library was also a breeze and allowed me to get my projects up and running in no time. I would totally recommend this shield for a beginner or even a professional looking to power up to 12V motors for its low price and easy implementation.
Power Boost 500 Shield. Photo Credit: Adafruit.com
Power Boost 500 Shield. Photo Credit: Adafruit.com
This shield is the latest shield I have worked with. I soldered up the headers and the on and off switch just yesterday! This shield by Adafruit is potentially going to be used in our Senior Project design granted it performs well in testing. The idea behind this shield is to take a single cell battery outputting 3.7V and boost the potential to 5V. This allows a single cell battery to power up your 5V Arduino project on the go! It also has a recharging circuit built in so that the LiPo battery can be charged via microUSB. All the indicators for ON, Charging, Done, and LOW are there to let you know that state of the battery. Another major plus is that depending on the size of the battery, it can fit nicely within the width and height of the stacking headers! So far testing has turned out great with 5V being supplied to my project with the use of only a single cell 3.7V 2,000mAh battery. This will save us plenty of space and take care of charging in one small stack-able package. Like most shields out there this one needed to be soldered before use and for that reason, I would recommend this shield to anyone as long as they can solder or know someone who can.
Click here for more information about this Adafruit shield.
The link above lists some cool shields to get you all started but don’t be afraid to look around for new and unique shields. Sparkfun, Adafruit, and other suppliers are constantly coming out with new stuff. To be honest, the possibilities of what you can do with an Arduino are endless especially when shields can be stacked on each other! Look out for my next Learning Arduino post about breakout boards and things I have needed to collect since starting this hobby!
As always thank you to everyone who has supported us and continue to share our posts and GoFundMe site. We really appreciate it!
Initial conceptual model for our UV done in April 2014.
First and foremost I apologize for the overall lateness of the content of this post, as I originally intended to publish this post in my previous round of posts, but due to time constraints decided to publish a post on a snake-proof full-body suit (equally interesting!) and invest a little more time into making this post a little easier to understand before publishing…hopefully it worked out, haha. So as I noted a while back (while discussing the future of undersea warfare), with growing challenges in the undersea and technological domains, innovation is becoming more and more important within the realm of defense engineering (as well as all other fields of engineering). One promising direction engineers are looking to in all fields of engineering is towards the application of advanced biomimetics (a.k.a. biomimicry) in their designs. Why might engineers and scientists want to study how we can mimic fish, or other animals or nature in general? Because nature truly is the ultimate engineer. Animals have been optimized to perform the tasks that they need to and to do so efficiently and thus have been nearly perfected for their environments and their lifestyles.
Considering the facts just presented, it becomes a little more evident why undersea warfare (as well as other undersea activities and applications) may benefit from the implementation of biomimcry. Take the Shortfin Mako Shark for example; this is the fastest species of shark in the world and it utilizes its large caudal fin (as will be defined later), slim, streamlined, torpedo-like body, and its stronger, faster-acting muscles (as enabled by its endothermicabilities, through which it generates additional heat through its unique metabolism, keeping the muscles warm and agile, thus defining the Mako as a “warm-bodied shark”) to reach cruise speeds of 25 mph and burst speeds up to 50 mph and leap 30 ft high! Another example of the awe-inspiring abilities of marine creatures and how scientists and engineers have attempted to mimic them is that of the color- and texture-changing abilities of the octopus, as Andrew talked about a while back.
Shortfin Mako Shark. Photo Credit: Sam Cahir via dmarron.com
To better understand more specifically how engineers can utilize biomimicry in order to advance undersea vehicle technology, we will now discuss how exactly fish swim. Fish generate forward motion, or swim, through what is termed locomotion. Locomotion is simply a fancy word for describing movement from one location to another; animal locomotion may take many forms and can be seen in all types of environments, whether terrestial (on land), aerial (through the air), or aquatic (through the water). There is a myriad of other qualifiers that can be used to further divide up the different kinds of locomotion (if you are interested, you can learn more about animal locomotion at this link), but we are going to solely focus on fish locomotion, that is, how fish get from one place to another.
Fish locomotion can be divided up into two main modes of motion: Body-Caudal Fin (BCF) and Median-Paired Fin (MPF). The BCF mode accounts for about 85% of fish families’ main mode of propulsion, whereas MPF makes up for about 15%. Now before diving into the swimming mechanisms associated with these two modes, we will make one more distinction: undulatory motion (also referred to as undulation) vs. oscillatory motion (also referred to as oscillation). Undulation is by far the most common type of motion (both within the BCF & MPF modes) and can be thought of as a lateral wavelike movement; picture a fish seemingly weaving its way through the water or a rope with waves travelling down its length…this is in essence what undulation manifests itself as: undulation in fish movement appears as lateral waves travelling down the length of the fish’s body. In short, undulation is lateral wave motion along the length of the body, relative to the body, as if the body was stationary but experiencing waves along its length. In contrast, oscillation focuses more on the body being essentially rigid and moving the tail side to side…picture your dog wagging its tail, or a pendulum oscillating about the line connecting the pivot point to the base. Now that we’ve got that covered, we can move on to quickly listing the common types of fish motion and listing a few examples!
Eel anguilliform lateral undulation. Media Credit: lyle.smu.edu
Time-lapse picture showing positions of a dog’s tail throughout its oscillation. Photo Credit: mediaorchard.com
Body-Caudal Fin (BCF) This type of movement depends on the fish effectively wiggling its body in order to move its caudal fin sided to side, thus producing thrust which has components in the forward, backward, and transverse directions. The largest component of this thrust is that in the rearward direction, thus the movement of the caudal fin propels the fish through the water.
Undulatory: 1. Anguilliform: With this kind of motion the undulatory waves are passed throughout the entire length of the body (except perhaps the head); because the entire body is extremely flexible, both forward and backward motion are possible. The most typical application in which you would see this kind of motion would be in eel locomotion. 2. Subcarangiform: This motion is similar to anguilliform, but the forward 1/3-1/2 of the fish does not move, while the rest of the body still generates transverse undulations. It is now significantly harder for the fish to swim backwards as it is not longer symmetric front to back and the forward portion of the fish is much more stiff than the rear. Common examples of fish with this kind of motion would be most trout and salmon. 3. Carangiform: Also similar to anguilliform, but only the last 1/3 of the body acts to produce thrust and the caudal fin itself is usually more stiff to produce greater thrust with the reduced active length of the body. Fish that swim like this are usually fairly narrow transversely, likely to increase the surface area used for thrust generation by increasing the height to width ratio; these fish also tend to be stiffer overall and faster moving. 4. Thunniform: In this group, all undulation is restricted to the caudal fin/tail and the region connecting the main body to the caudal fin (called the peduncle); these types of fish usually have very large, stiff caudal fins, have been optimized for high speeds and long distance travel, and are capable of generating hydrodynamic lift in order to compensate for the fact that many of them are not neutrally buoyant and thus need to move (and in doing so, generate lift) in order to keep from sinking. Examples are most species of tuna and sharks.
Oscillatory: 1. Ostraciiform: These types utilize slow pendulum-like movement of large caudal fins and are similar to Thunniform, but operate much more slowly. As a result, this type of swimming is usually either simply an auxiliary, low-energy style of swimming used by some MPF fish or, if used by fish as their main style of propulsion, those fish would generally have internal countermeasures such as poisons since they are incapable of fleeing predators.
Various physical characteristics of a generic shark, nearly all of which appear on most fish. Photo Credit: Wikipedia.org
Median-Paired Fin (MPF) This type of movement depends on synchronization of various combinations of usage of the pectoral, dorsal, pelvic, and/or anal fins.
Undulatory: 1. Rajiform: Characterized by vertical undulations along large pectoral fins…think sting rays and manta rays for example. 2. Diodontiform: Characterized by undulations that travel along large pectoral fins…like a porcupine fish!
Porcupine fish with undulating pectoral fins; Diodontiform motion. Media Credit: Tumblr.com
3. Amiiform: Utilize long undulatory waves along large dorsal fins, such as a Seahorse. 4. Gymnotiform: Uses undulations of a long anal fin; much like the Amiiform, but using the anal fin on the underside of the fish rather than the dorsal fin on the top side of the fish. An example is the American Knifefish. 5. Balistiform: Anal and dorsal fins undulate; while rare, this can be seen in the Triggerfish.
Oscillatory: 1. Tetradontiform: Dorsal and anal fins oscillate either in phase (together) or opposite of each other; an example would be the Sunfish. 2. Labriform: Pectoral fins osciallate in a way in which they produce both lift and drag, which can be resolved into components, one of which would be rewards, thus producing thrust. In essence, the fish flaps and rows its pectoral fins, producing thrust. An example of a fish using this kind of motion would be the California Sheephead.
So there you have it, an organized view of the many sorts of propulsion mechanics associated with fish, each having its own advantages and disadvantages. By studying these kinds of characteristics of fish, scientists and engineers can come up with innovative solutions by looking to the sea for the answers for the one constant truth for scientists and engineers alike is that we never stop learning and so when you can’t find a sufficient answer in your textbooks and theories, you need to be able to conduct experiments and analyze the world around you in order to come up with new ideas.
Personal sketch of a conceptual UV following a submarine in the distance(April 2014).
This is exactly what engineers within the defense industry are doing currently as they conduct research and begin designs of new cutting-edge, innovative undersea vehicles that utilize biomimicry to provide for increased performance, better power efficiency, and increased stealth through the minimization of flow signature. While we here at Team UV are not utilizing biomimicry in the design of our propulsor (for which we use something else all together), we absolutely have biomimetic influence within our design and as can be seen in the picture at the top of this article, have looked to adapt a streamlined shape and fin-like control surfaces in addition to a number of other biomimetic schemes (i.e. stability, maneuvering, buoyancy control, drag reduction, etc.) to produce a truly innovative solution that is currently in the manufacturing/assembly stage. And so we again ask for your increased support through our fundraising campaign at GoFundMe.com/TeamUV as we near the end of our project in the coming months.
As promised, in another week or two, we will release some pictures of the current vehicle design/model.
Not the university mentioned in the post, but you get the gif! Photo Credit: gifpins.com
Facility maintenance engineers are often under-appreciated in the world of science and technology but their important roles should not be overlooked. They are tasked with various duties such as retrofitting machines and components, replacing equipment, and preparing maintenance schedules to make sure everything is working smoothly and continuously. A strong background in machine design, electromechanical interfacing, HVAC design, and project management is required to keep a facility in working order. Of all the other things not mentioned already a facility maintenance engineer has to assess damage and create a recovery plan in the case of a system failure. Just last July, a local university campus experienced a terrible water main rupture. The break of the 100 year old, 30 inch main resulted in the release of more than 20 million gallons of water compromising 900 vehicles, submerging athletic fields, and flooding nearby structures. What a tough gig for any engineer! The goal of this brief Open Mind is to show how I would reconstruct after such a terrible event.
Students making the best of the situation. Photo Credit: NBC News
The first plan after analyzing what exactly happened is to perform a major clean up. I would establish a best way to clear the parking structures and other flooded areas to minimize damage done to structures, vehicles, and exposed equipment. Pumps would have to be sized and storage/where the water will go will have to be determined.
Next, deep analysis of structural integrity will be performed to make sure all exposed buildings are sound. Not only can water lead to mold and soften building material but it can also get into the thinnest cracks causing localized damage over the long run. All exposed building would have to be cleared before being opened for use.
Pipe Robot. Photo Credit: technovelgy.com
Finally, active prevention action will be used to ensure no further catastrophes happen again and if they do, not to the magnitude of this recent event. I would undergo a full and regular inspection of all major systems used by the campus/business. Emergency detection systems can be developed to continuously monitor various system parameters and issue an alarm when critical levels are reached. In an ideal world with endless money, I would also employ inspection robots that can go into piping networks or other systems that are hard to inspect and have them repair issues as they come up. Easier said than done!
Look out for my next installment of Learning Arduino this week where I cover more example sketches and projects! Also, continue to share and support our GoFundMe site! We have raised over $1,600 thanks to our generous donors!
2015 National Conference on Undergraduate Research. Photo Credit: CUR.org
A few days ago, Team UV was selected to present some of our research regarding our underwater vehicle and its propulsion system at the 2015 National Conference on Undergraduate Research, which will take place at the Eastern Washington University from April 16th-18th! Thank you to our readers for your support and for following our blog; we will not know what day, timeslot, or room we will be presenting on/during/in until early March.
Also, we want to thank those of you who have contributed to our fundraising campaign and mention that we have now raised $1,630 thanks to your generous donations! Thank you for your support and please continue to help spread the word as we continue in the purchasing and manufacturing stages!
We also want to note that no donation is too small and not a single penny donated will go to waste, it will all be used to increase the quality of our vehicle, to add capabilities (through additions to the sensor suite or additional drag-reducing technologies, etc.), and to enable us to conduct better testing (i.e. the construction of a flow tank for actual flow visualization). As an example of this, we are excited to inform you that through some of your donations we have been able to get our hands on a superhydrophobic substance (from Hydrobead) that will help us to decrease drag on the exterior of our vehicle significantly through the repulsion of the surrounding water. As follows from the above statements, any money that we raise above the $5,000 will be put directly into the project in one of many ways, including (but not limited to) those listed above.
Dyed water drops on wood coated with a super-hydrophobic substance. Photo Credit: TheFutureofThings.com
In addition to this, at this point, it is unclear as to where the funding to attend our research conference will come from (whether out of pocket or at least partially funded through our school’s research office), so all donations will help us significantly!
Lastly, I want to remind our readers that we will be trying to post funding progress updates as often as possible and that you can find a full-sized PDF of our pull-tag poster on our Sponsors & Donations page if you would like to print one out and post it to help get the word out. If you would like to help out in other ways, it would mean a lot to us if you would tell your friends/family/coworkers/etc. about our fundraising campaign (and possibly ask them to share it as well), share it on Facebook, or perhaps even just spread the word about TeamUV.org in general, as our biggest goal with regards to this website is to inspire interest in the fields of Science, Technology, Engineering, and Mathematics (STEM).
Any help is greatly appreciated and please come back Sunday for Andrew’s Open Mind post!
Schlieren photograph of a scaled model of the SLS being subjected to (scaled) supersonic speeds. Photo Credit: NASA.gov
About a week ago, NASA tested the RS-25 rocket engine on the new Space Launch System (SLS), a launch vehicle that will drive the next generation of space shuttle deeper into space than we have been able to go thus far. The video (shown below) has been made available to the public and provides an excellent excuse for the discussion of compressible flow regimes.
In the past, our readers have been exposed to the world of fluid mechanics quite often (whether through aeroacoustics, turbulent vortices, hydrodynamic drag, or various other phenomena), and have even been exposed to the subject of compressible flow briefly, so today I am going to give you a bit of an introduction to the subject of gas dynamics and then I will explain the different flow regimes associated with compressible flow.
Fluid mechanics, as discussed previously on this website, is the study of fluids (liquids, gases, plasmas), their movement, and how they interact with internal and external stimuli (loading/forces, pressure differentials, dissipative effects, heat transfer, etc.). Today, we will only be looking at gas dynamics, which differs from the study of liquids in that, for most purposes, liquids (i.e. water) are assumed to be incompressible. With gases, this is not the case. Due to the greater amount of space between free particles, gases have a much greater ability to be compressed. Owing to this compressibility, the terms “gas dynamics” and “compressible flow” are often used synonymously to refer to the same field of study, as compressibility becomes a vital factor as the speed in a gas flow is increased.
Particle spacing in solids, liquids, and gases. Photo Credit: Wikimedia.org
As a result of this compressibility, two important phenomena are uniquely encountered within the field of gas dynamics that play a huge role in high speed gas dynamics, as will be defined shortly. The first of these is the choked flow condition, which finds application in the usage of convergent-divergent nozzles (amongst other things), but which will not be discussed here for simplicity. The second of these is the formation of shock waves. Shock waves are essentially pressure waves that have coalesced together to form a “Mach wave”, which represents a discontinuity in the flow field….right, so what in the world does that mean? If an object were to be stationary in the air and have pressure waves emanating from it, they would propagate out in all directions at the same speed (the speed of sound) and form concentric circles about the object. However, as the object begins moving (within subsonic flow), the pressure waves become sent out at different times; in essence, the object sends out a pressure wave, then moves forward and sends out another, and so on (although, this happens basically continually).
As the object’s speeds increase, the center points of these waves get further apart, and thus the waves become compressed in the direction of motion, and expanded in the opposite direction. Eventually, if the object continues moving faster, the object will be moving at the speed of sound, meaning that the object will be travelling at the same speed as the pressure waves are being sent out…in essence, the object has matched or caught up with the pressure waves that it is sending out, and so when the object sends out more pressure waves, they can no longer propagate forward from the object, but rather travel at the same speed, while the portions of the waves traveling backwards are now being left in the dust…figuratively speaking. The waves that are being emenated from the object all at the speed of sound are now really close together and essentially stack up and coalesce into one solid pressure wave that is termed the shock wave. This shock wave can be heard as a “sonic boom” due to the discontinuity or abrupt change in pressure across the shock wave (forward of the wave, the flow is moving at the speed of sound and very low pressure, behind the wave, the flow is moving slower and at a higher pressure). As the object speeds up even further, the object is now starting to outpace the pressure waves all together in what is called supersonic flow, so that the object is leading the waves, which begin to form a mach cone around the object; inside of this mach cone is referred to as the zone of action, while outside of the cone is referred to as the zone of silence. If the object moves even faster, it will eventually get to a speed so high (that of hypersonic flow), that the shock cone will tightly hug the skin of the object so that the distance is so small between the object and the shock wave, that the air gap (the shock layer) begins to heat up due to viscous effects and the aerodynamic heating effect, leading to what we term “high-temperature chemically reacting flow”; the flow is so hot that the gas begins to dissociate or ionize!
So at what speeds does this all occur? To find this out, we define the Mach Number (a.k.a. M or Ma) as the ratio of the object’s speed to the local speed of sound; to understand this, a value of 0.5 would mean that the object is moving at half of the local speed of sound, 1.0 would mean the object is moving at the local speed of sound, and 2.0 would mean the object is moving twice as fast as the local speed of sound.
Up to a value of Ma 0.3, the flow is described as incompressible and thus is analyzed similarly to other incompressible fluid dynamics such as most liquid flow. An example of incompressible flow would be what the baseball encounters when you play catch with a friend.
Baseball in incompressible flow. Photo Credit: Hilltop.Bradley.edu
Once the object hits Ma 0.3, the flow is considered compressible and subsonic in that the object is still moving slower than its pressure waves. An example of subsonic flow would be the flow around many .38 Special bullets.
Bullet fired from a Smith & Wesson 686 .38 Special. Photo Credit: Wikimedia.org
Once the object reaches about Ma 0.8, transitional instabilities begin to set in and persist to about Ma 1.2; this regime is termed the transonic flow regime and can be seen in basically any application wherein an object is accelerating to supersonic speeds, as the object must pass through the transonic regime to reach the supersonic regime.
Above Ma 1.2, the shock waves have generally been established in full and the vehicle can be said to be in the supersonic flow regime. Applications include supersonic jet engines, such as those found in many military aircraft and supersonic ammunition. More photos will be included here since supersonic flow is the meat of this post.
Shock diamonds in a supersonic XCOR Liquid Oxygen-Methane engine. Photo Credit: WordPress.MrReid.org
F-15 showing shock diamonds while in supersonic flight. Photo Credit: RobHansonPhotography.com
Supersonic bullet showing shock cone, pressure waves (look closely), and turbulent wake; visualized using the shadowgraph method. Photo Credit: Wikipedia.org
Lastly, above Ma 5, the aerodynamic heating effect comes into play and the flow enters the hypersonic regime. Applications are hard to come by as this is a subject of a great deal of current research within the fields of mechanical and aerospace engineering (more specifically fluid dynamics); however, one instance of this kind of flow that nearly everyone is familiar with is that of the space shuttle, especially during what is termed re-entry. In fact any re-entry vehicle will experience hypersonic flow, and very likely “hyper-velocityflow” which is essentially an upper range of hypersonic flow speeds.
Hypersonic wind tunnel testing at Ma 6. Note the thin nature of the shock layer. Photo Credit: Gizmodo.com.au
Time lapse of LGM-118A Peacekeeper missile re-entry strike bodies touching down, after having traveled through the atmosphere at speeds up to approximately Ma 20. Photo Credit: Wikipedia.org
Most of us can remember the days in elementary school where we learned to make paper cranes, flowers, boxes and all manner of things just by folding paper. I was never one to master the art of origami but I can make a pretty nice paper air plane! This technique of folding paper has generated a lot of interest in the engineering world. The National Science Foundation has provided a grant to a few top universities to research this. The goal is the creation of materials that can fold up into very small places and then unfold when needed. Imagine a solar collector that could unfold like a flower in sunshine then collapse again at night or when power is not needed. Read a full article about it on the American Society of Mechanical Engineers’ website here: https://www.asme.org/engineering-topics/articles/design/engineering-meets-art
Newton’s 3rd Law of Motion. Photo Credit: Buzzle.com
Prompt: Boston Dynamics is a company that specializes in producing robots that can really do the unimaginable. Take Sand Flea. Sand Flea weighs 11 lbs and can jump to heights of up to 30 ft. Such a feat represents a very attractive design goal across all industries for the coming years: the ability to store massive amounts of energy and release it very quickly. Considering that these high energy-density type systems are in fact the way of the future, using what you know about energy come up with either at least 3 ways of storing/quickly releasing a large amount of usable mechanical energy or come up with one way and describe at least 3 ways to look at your solution.
There are countless applications for these kind of high energy-density storage, quick release type systems; however, in this post, we will simply be looking at a few design considerations that a mechanical engineer would have to account for if he/she wanted to design a robot capable of jumping to great heights by taking advantage of the expansion associated with the release of compressed gases.
As shown above, Sir Isaac Newton’s 3rd Law of Motion essentially states that for every action, there is an equal and opposite reaction. This simple statement has profound complex consequences in the real world. If you have ever seen a spaceship lift off, felt the recoil from a firearm, had a hammer bounce back at you after hitting a nail, or wanted to see what would happen if you were to use a fire extinguisher as a booster while sitting in a rolling chair, you have seen the phenomena that Newton’s 3rd Law of Motion is referring to.
Fire extinguisher + rolling chair = fun. Media Credit: Brooklynn99Insider.com
Now in reality, things get much more complicated as there are many inter-dependencies that affect these reactions (i.e. the reaction of air resistance on the skin of the spaceship, the rerouting of gases in automatic weapons to chamber the next round and reduce recoil, the elastic properties of the steel head of the hammer, the rolling friction of the chair wheels or that associated with the bearings of the wheels, and the list goes on…).
So getting back on topic, what would we need to consider if we wanted to design a robot that used compressed fluids to jump?
Fluid Mechanics As a class of fluids, gases are much more compressible than liquids; this fact, in combination with the tendency of gases to fill the shape of their containers (or flow paths) makes them ideal for use in high-compression fluid storage to be used for imparting large amounts of kinetic energy to objects via momentum transfer from their expansion kinetics. By storing a large volume of gas under heightened pressure within a properly suited pressure vessel (PV), large volumetric expansion ratios/rates can be realized when the gas is released. This gas expansion leads to massive amounts of energy being released very quickly from these areas in which massive amounts of fluid can be stored in a very compact space (thus high energy density storage and fast release). The energy and momentum associated with this gas can be used to propel our robot up and into the air, but know what? Did we intend to design our robot to be single use or do we want it to be able to jump again? We need to find a way to refill the system.
The means by which these systems are refilled or “recharged” is most often dependent on the kind of gas being used. In order to replenish your energy stores in an air-based system, you could simply pull the air from the atmosphere using an air compressor (although this becomes significantly harder when you are for example 500m under the ocean’s surface). Another complication associated with this method is the fact that an air compressor may not be ideal for our application on the basis of size, weight, vibration, noise, power requirements (as the air compressor will up the robot’s power requirements and thus decrease its run time for the same amount of power supply or even necessitate the use of all new control circuitry), etc.
This situation is complicated even further when the gas being used is not air, as now you have to store all of your gas reserves unless you can find out some way of extracting the gas you need from the atmosphere, which is simply not feasible, especially on such a small scale. So how do we get around these limitations?
Daisy Red Ryder BB Gun. Photo Credit: ehstoday.com
Many air-based systems use air-pistons in order to recharge their compressed gas reserves as anyone who has ever had to pump a BB gun or water gun has experienced. The mechanism for actuating this piston is not always something as obvious as the lever action on your Daisy Red Ryder BB gun (remember to always practice proper gun safety, lest you shoot your eye out…referencing the movie A Christmas Story). Some systems may have a protruding pin that (when depressed) cycles a small pump compressor or reciprocating piston to recharge thy system. In some applications, exhaust gases may be re-routed and used to actuate the compressing mechanism. Technological creativity knows no bounds and, as such, it is more realistically finding a way to recharge a system comes down to design time, costs, and other system-level tradeoffs. Would it not be easier if we simply did not allow the gas to ever leave the system in the first place?
We could create a closed-system by using a highly elastic material to cover the exit nozzles of our robot, so that when we released the gas, it would rapidly balloon out and propel our robot through the elastic collision interaction mechanics between the gas-filled elastic material and the ground (think Newton’s 3rd Law of Motion) without expelling the gases to the atmosphere. To better understand this, visualize taking one of those squeeze toys where the eyes bulge out (see below) placing the toy with the eyes against the ground and then filling the eyes with a ton of gas really rapidly and watching the thing fly up in the air! This is just one example of the open-minded nature of engineering problem solving. The only bummer would be that in reality, this feat would likely be far more difficult than stated here and would likely require the development of a custom material with the proper amount of elasticity or “stretch”, tensile strength, strain-recovery time (how fast the material returns to its original size/shape), and would likely need include stiffer/more rigid pads where contact would be made with the floor so that the material could transfer more of the gases kinetic energy to the ground (rather than simply absorbing all of the gas’s energy through the material’s ductility).
Thermodynamics/Heat Transfer In order to bring this article to end sooner rather than later (sometimes I get carried away and don’t realize how much I’m writing, so my apologies!), I will quickly move through this subject for consideration as well as the 3rd one.
Most gases would experience significant thermal energy generation under large compression ratios and thus the surrounding system would likely require cooling to prevent damage to the electronics or to the user; this cooling could be accomplished by passive controls such as extended surfaces/fins or forced heat transfer by way of a fan – the cheapest active thermal control. You have likely seen both of these types of systems mounted to your computer’s CPU.
Fan mounted to extended surfaces on a CPU. Photo Credit: Wikipedia.org
Mechanics of Materials A very noteworthy consideration in this application would be the strength of the pressure vessel (PV). Depending on gas used, compression ratio, allowed temperature rise and transmittance of impulse (high energy transfer over small time period) to the PV, hoop stresses (circumferential) can become significant and therefore require thicker PV sidewalls, use of stronger material for the PV, or rib reinforcement of the PV.
Pressure within a pressure vessel (in this case a CO2 canister). Photo Credit: science-of-speed.com
So anyways, there is a long-winded look into just a few of the many, many things a mechanical engineer might consider in their design of a robot capable of jumping to great heights using compressed gas. One of the many beauties of mechanical engineering is the fact that it is such an incredibly open-minded field that requires creativity, intelligence, determination, and the realization that there is never one right answer.
The idea of 3D printing is spreading around into all kinds of different disciplines, from cooking to make up. In engineering the idea of 3D printing has been around for a while now. But more recently it has become accessible to the average consumer. Some organizations made 3D printer designs open source, meaning that they published their designs on the internet free of charge. This allowed anyone with some know how to make their own. Once the average hobbyist could invest in the technology it began to get more interest and eventually has become the thing that it is today. As an additive manufacturing method for prototypes, or single production runs, where strength isn’t a huge concern 3D printers open up a huge world of design to the interested population.
Team UV Badge, representing our principal application (ISR), and our potential future applications (Mine Detection, Underwater Inspection, and Exploration).
Team UV would like to update our readers and supporters with regards to the progress you all have helped us to make through our fundraising campaign. As of today (January 7th, 1525 hours), we have raised $1,620 of our goal thanks to your donations!
As a way of saying thank you and hoping to share a little more about our project with you, we will be publishing some images of our project over the next few weeks. The reason we have refrained from posting any pictures from our project in the past was due to the proprietary nature of many of the systems on our vehicle (and the vehicle as a whole), but we are realizing more and more how important it is that we share a little more of what we are doing with our supporters. So without further ado, below we have posted 2 pictures of SHEILA-D (Submerged Hydrodynamically-propelled Explorer, Implementation: Los Angeles – Demonstrator).
Left: SHEILA-D producing thrust. Right: SolidWorks 3D model of SHEILA-D.
SHEILA-D was our propulsion system demonstrator that we designed, built, and tested over a span of 36 days and 850 (by conservative estimates) man hours during Phase I of our project (which took place during our Machine Design lecture/lab combo in Spring 2014). The goal for SHEILA, was to demonstrate the ability to provide thrust with our innovative underwater propulsion system, and in this respect we succeeded. However, we were aware of many shortcomings from this initial design (i.e. poor material choice as influenced by cost/time limitations, poor tolerances, etc.) and thus revamped our efforts with regards to the propulsion system during Phase II [the senior project portion/development of the entire vehicle from late Spring 2014-mid Spring 2015 (project symposium)]. For more information on the history and plans for this project, please check out our About page.
We are currently in the purchasing portion of Phase II (to be followed by manufacturing/assembly, programming, testing, final analyses, and report/presentation preparation) and thus could use funding now more than ever. We would like to thank all of you for supporting our efforts and ask that you please continue to share our website and our fundraising campaign (GoFundMe.com/TeamUV) with as many people as possible. No donation is too small and for those who know the team personally, offline donations are welcomed as well.
This post will be reposted on our fundraising page, and 1 week from now we will post some pictures of the original Phase II full-vehicle concept, with the actual Phase II vehicle computer model pictures coming 1-2 weeks after that, so please be sure to check back often and remember, tomorrow Ben will be posting a Presentation post at 1000 hours!
Oxygen-absorbent crystals before (left) and after (right) becoming saturated with oxygen. Photo Credit: TheHigherLearning.com
71% of the Earth’s surface is covered with water and, for the most part, it is unexplored by humans…until now! Scientists from the University of Southern Denmark in conjunction with the University of Sydney, Austrailia have discovered a crystalline material that is capable of absorbing oxygen from both air and water! This revolutionary material can bind and store oxygen in high concentrations then control the release time of that oxygen depending on what the user needs. The benefits to this are unquantifiable but could be especially beneficial to deep sea divers and to those suffering from respiratory ailments.
A study led by professor Christine McKenzie alongside Jonas Sundberg of the University of Southern Denmark involved about 10 liters of microscopic grains of the material and found them to be enough to suck the oxygen out of a room. Even just a few grains contain enough oxygen for a single breath and that material can even absorb and supply oxygen from water surrounding deep sea divers. The oxygen saturated material is so effective that it is comparable to 3 full pure oxygen tanks under pressure! One of the key ingredients is the metal cobalt in the material which controls the process of absorption which gives it the molecular and electrical structure to be capable of absorbing oxygen from air and water. Remarkably the absorption and releasing process can be done many times without losing the ability much like a sponge in water. The impact that this discovery will have on the medical field as well as exploration will be monumental and I look forward to it. For more information please visit: http://www.collective-evolution.com/2014/10/10/absorbing-crystal-can-steal-oxygen-from-air/
Hot beverage and a book by a fireplace. Photo Credit: honeymoon-adventures.com
Winter is a wonderful time to sit by a fireplace, drink a hot beverage, and listen to the rain pound the windows from outside. Even in this cozy setting the engineering principles of fluid mechanics are hard at work.
Flames rising from burning logs always have a way of mesmerizing me, the way they dance mischievously around and leap for the chimney captivated my curiosity since I was a child. Now that I am an engineering student I can explain what causes them to act the way that they do. There are two basic principles that can explain this. The first is as simple as the fact that hot air rises, the hotter the air the faster it rises. The second is that as things get hotter they emit radiation that we see as light, like red hot metal. If you put these together you find that flames are actually a mix of air and smoke that are so hot that the radiation they emit is in the visible spectrum. The flames dance over large fires because of disturbances in the air and because the air is so hot that it rises fast enough for the air to become turbulent. Yet over a candle the flame can stay relatively steady. This is because the air is rising slowly enough, and with few enough disturbances to remain laminar, or steady.
For me the pounding of the raindrops on the windows bring another level of authenticity to the fireside. That being said I am from San Diego so I don’t get rain often in any season. All of this water stays up in the clouds floating across the land and then finally dumps to the ground below. But what causes the trapped water to finally fall? In damp air there is a lot of water vapor that would like to form together and form droplets but it takes a lot of energy. The energy required to form a droplet is related to the surface area of the droplet so a perfect sphere of water forming is very unlikely, there is simply too much energy required to maintain the surface area of a sphere. However, if there is a speck of dust floating around in the air water can form to it. The water only has to maintain a fraction of a sphere of surface area because the dust covers the rest. As water vapor condensates on these small particles they become heavier and eventually fall out of the bottom of the cloud and bring the water back to the ground.
Finally no cozy fireside day is complete without a hot beverage by your side. These beverages never stay hot for long enough. This is because of the natural convection moving air around your mug. While that may sound a tad complicated, it’s based on the same principle that the flames were above. Hot air rises. This means that the air around your mug was heated by the hot beverage, this hot air rises away from the mug and draws cool air up to take more heat. The cycle continues until you finish the drink or it gets disappointingly cold.
Next time you sit by the fire with your drink think of what you’re seeing and let your curiosity take you into the realm of engineering.
Happy New Year from Team UV! Hope you all enjoyed the past year and are looking forward to some new and beautiful things to come in 2015! Being the first post of the year, I’ve decided to start it off right with something uplifting!
Airfoils. Who needs them, right? Well actually a lot of people do, especially if you want to fly. Looking at an airfoil, you might believe that lift is created because one side is curved and the other flat. This however would suggest that lift is only possible in that particular orientation but that is simply not true! If it were, then how could airshow pilots routinely fly upside down for extended periods of time? These are the questions we should be asking people!
Airfoil pressure field distribution. Photo Credit: av8n.com
To fly, it is not necessary to change the shape of the wing when inverted. Actually, any normal shaped wing can fly fine when inverted. It may look a bit weird and the inverted-stall may not be optimized but it does create lift by the same principles as the right-side up wing. Remember, lift is more a function of angle of attack than simply shape.
Airfoil chord and camber lines. Photo Credit: av8n.com
The chord line is a straight line drawn from the leading edge to the trailing edge of the airfoil. The mean camber line is a curved line drawn from the leading edge to the trailing edge that always stays halfway between the top and bottom of the airfoil. The amount of camber an airfoil has is determined by the greatest distance between the mean cambered line and the chord line. If the mean chamber line and the chord line are the same, then you have a symmetric airfoil. A general rule of thumb is that symmetric airfoils are preferred to highly cambered airfoils in small angles of attack, and the opposite is true for higher angles of attack. This is shown in the figure below where the airfoil designated 631-012 is symmetric and 631-412 is the slightly cambered version. Besides one being slightly cambered, the airfoils are pretty much identical. Beyond 12 degrees relative angle of attack you can see that the cambered airfoil has a big advantage over its symmetric counterpart. The cambered airfoil does not stall until a higher angle of attack around 18 degrees and as a consequence its maximum coefficient of lift is much greater. An intuitive explanation would be simply that the slight camber allows for the leading edge to slice through the air easier. Taking this to another extreme, a reverse cambered airfoil would not be a good idea because it would stall even earlier than then symmetric airfoil (which is why you don’t see these). A reason for having a large camber would be in landing or lifting off situations and usually extending the flaps of the wings is sufficient in increasing the camber.
Airfoil Coefficients of Lift & Drag as a function of Angle of Attack. Photo Credit: av8n.com
Effect of wing flaps on camber. Photo Credit: boldmethod.com (modified)
Again it is important to reiterate that lift is more a function of the angle of attack rather than simply the shape of the airfoil. If the coefficient of lift was only dependent on the camber of the wing (which doesn’t change often during flight) then the plane would only be flyable at a special airspeed designed for that particular cambered wing. In reality however pilots have to constantly change the angle of attack to maintain steady lift. For more on lift, airfoils, and flight please visit: http://www.av8n.com/how/htm/airfoils.html. Have a happy new year!
ISS Commander USN Captain Barry Wilmore holding a 3D printed wrench. Photo Credit: InterestingEngineering.com
Barry Wilmore, International Space Station (ISS) Commander, recently needed a wrench that they didn’t have at hand on-board the ISS…so NASA emailed him one. For the first time ever, an object has been designed on Earth and manufactured in space. In earlier years if a situation arose similar to this then the people on the ISS would have to wait for the next resupply mission which could take months! “Made in Space”, a California company designed a micro gravity printer that sits aboard the ISS. Now astronauts can simply print the desired tool they need.
Now whenever something is needed on the ISS, they can now send the requirements to Made in Space, who then mocks up the part in CAD software before sending the data back to be printed in space. However, this is not the first 3D printed part in space, back in November the printer printed a spare part for itself. This means that they can take less tools with them when they travel to the ISS. 3D printing filament is much lighter than tools! In total, 21 objects have been 3D printed in space, all of which have been brought back to Earth for examination and testing. This can only help to improve the printing process in micro gravity. Now only imagine if we can 3D print a spacecraft…Hey…..It could happen!
The word “engineer” can mean a lot of things. The word “engineering” can mean even more. Both words can be hard to relate to especially if you haven’t studied or practiced the discipline. However, it is often easier to relate to these and similar words by examining a tangible example. Many of the things we use everyday utilize multiple principles of engineering that most simply overlook. I am here to put a mini-spotlight on just one: the trusty stapler. We all know what a stapler does and how it works but what “engineering” principle went into the bringing of our powerful and hinged friend to life, figuratively speaking of course.
Good ‘ole vector statics comes into play in the form of a spring interacting with loaded staples. When the stapler is closed and not moving, an extension spring is elongated usually inside the hood of the staple chamber and provides a component of force in the direction of loaded staples. When you staple together your 20 page single-spaced research paper on naturally occurring composites, this force component slides the next staple into position ready to staple whatever other monstrosity of a report you may have lying around.
The stapler is a machine so it would be smart to assume that machine design and stress analysis are heavy hitters in the world of staplers. Individual staples are easy to remove from one another and that is because they are held together by a weak adhesive. This weak bond is important because if it were too strong, the staple would never succeed to touch the surface of your 40 page chemistry lab report that you worked on all quarter. This bond between the staples has to fail in shear, so the bar that comes on top of the staple must provide enough stress at the bond to shear away the staple from rest, through the thick stack of pages, and onto a low friction finish plate that bends the tips of the staple around the last 9 weeks of your life.
The last but definitely not the least of the engineering principles embedded inside the stapler is material science. When staples are purchased from your local stapler and stapler accessory store they are straight and bent at 90 degree angles on both ends. After being used on your 110 page Matlab project report, these angles can change to 180 degrees or more. Strain hardening occurs at the bent sections of the staple after being used which provides a more secure hold on the pages of which your deepest and most profound thoughts are printed upon.
It is important to keep in mind that the things we buy off the shelf don’t simply appear magically. Even the simplest of these things go through myriads of engineering principles before it’s ever machined or even designed. Just keep that in mind next time you’re using your cellphone or opening a door or even putting on your shoes.
While there are many stunning artificial Christmas trees on the market there is nothing that can beat a real Christmas tree. The species of tree for the festive holiday varies in different parts of the world, they all have roughly the same green foliage and smell. When it comes to getting a tree to decorate for the holidays you’re faced with one problem regardless of the species you go for in that the leaves or needles will turn brown and fall off. A group of schoolgirls in Australia have now come up with a simple solution to make the Christmas tree last longer in the home.
A year 7 class of girls from a school in Rose Bay, Sydney, Australia, looked into what made the foliage of the typical Christmas tree turn brown and shed the needles. They looked at the trees in different conditions. They placed branches into tap water, hot water, beer, energy drinks and a container that had water with the branch being sprayed with hairspray. They performed the experiment with 50 branches of Pinus Radiata, otherwise known as the Monterey Pine tree. They divided the branches into groups of 10 and checked the branches out carefully over a period of 27 days. They used an instrument to measure the leaves health by applying a pulse of light. This measured how efficiently the needles converted light energy to chemical energy.
Professor Moles said that she believed that the coating of the hairspray stopped the plant from being able to sense chemicals that came from the branches that were dying, which in turn would normally trigger more decay. This works in the same way as leaving a rotten apple in a bowl and it turning the whole bowl bad. Another theory was that the hair spray may have helped to keep moisture in. So it seems that if you want to get the best from your Christmas tree you should give the tree a spray with some hairspray. Of course, it would be advisable to do this before you decorated the tree.
This may be a tad bit late considering the timing. I know I will make sure to remember this next year!
Ballerina in ballet shoes. Photo Credit: rebloggy.com
Now more than ever, kids are being introduced to the possibilities of a career in engineering and the sciences. There are commercials encouraging young scholars to study engineering and plenty of programs to help underrepresented demographics obtain a scientific/technical degree. Even other fields of study such as business and apparel merchandising management (AMM) are offering classes to become better versed in solving technical problems.
CPP Bronco Esthella Gonzalez. Photo Credit: Cal Poly Pomona PolyCentric
A few weeks back, I stumbled upon an article written by Carly Owens about a fellow CPP Bronco named Esthella Gonzalez. Esthella is a recent AMM graduate who took a more technical approach to her senior project. She was tasked with tackling a sports related apparel problem commonly found in ballet. Pointe shoes, the one’s used by ballerinas for dancing on the tips of their toes, have very high wear rates.
Ballerina shoes typically wear out after about 20 hours of normal use and can be completely worn down even after one performance. This has caused a major need for better materials and performers have been calling out for someone to help with this problem for years. Esthella started out her research by running 14 materials through common textile tests also used in the engineering field: tear strength, seam strength, and abrasion resistance. Similar tests also are used to determine mechanical properties of materials and for the classification of materials commonly used in engineering practice.
Seam Strength Test. Photo Credit: 4U2SEA.
Esthella at first dreaded her given task but, through hard work, has achieved great success in here findings. She found that a material called Gabardine, composed of mostly polyester, performed the best overall in all three tests. It outperforms the traditionally used Satin which can run into the thousands to repair. This cost is also compounded by the fact that ballerina shoes are all custom made. After finding success in her two-quarter long project, she was encouraged to continue research and even submitted an article to the academic journal Fibers and Polymers.
Introducing students to the world of science at an early age and encouraging those interested in it to continue their study is only a good thing. Aside from advancements in consumable technology we can expect to see advancements in fields not commonly tied to engineering. The medical field and agricultural economy for example always benefit from new breakthroughs in science and cutting edge equipment. Esthella’s unexpected blend of science, engineering, and apparel is just the tip of the iceberg!
Until next time!
To support the completion of our project, please check out our GoFundMe site and pass it along to your friends. We are nearing our first milestone of $1,000 and need your help! Thanks everyone!
The 2014 year has been a good one to us in terms of technology. Many of these devices have not been publicly displayed enough for people to take notice. So I’m here to fill you in! Here is your list of the top 10 greatest feats in engineering!
10. Form-fitting compression space suit to aid in planetary exploration -Dr. Dava Newman, a professor of Aeronautics, Astronautics and Engineering Systems at MIT, created compression garments that incorporate small, springlike coils that contract in response to heat to improve upon the outdated, clunky spacesuits astronauts currently wear.
9. Simple, cheap, paper test for cancer -Another research team at MIT has definitely achieved success in this department as they developed a simple, cheap, paper test that can diagnose cancer, in a similar fashion to a pregnancy test.
8. Pocket spectrometer is your personal molecular scanner -This pocket friendly device uses near IR spectroscopy to identify the materials of the object it’s scanning. It works in partner with your smartphone via Bluetooth and the data from the scan is sent to the cloud to undergo algorithms, before feedback is sent back to the smartphone.
7. Daewoo’s exosteleton that gives its workers super strength -Daewoo began testing exoskeletons that allow workers to pick up, maneuver and hold objects weighing 30kg with no effort – perfect for their shipbuilders. A backpack carries the power for a system of hydraulic joints and electric motors running up the outside of the legs.
6. We finally have something that can be called a working hoverboard -An interesting use of electromagnetics and the hoverboard was a front for the new take on the technology which has potential for a lot of other great possibilities.
5. Ridiculous 43 Terabits/sec data transfer -The High-Speed Optical Communications team at the Technical University of Denmark set a new record for data transmission this year, passing 43 terabits per second worth of data over a single optical fiber. To put this in perspective, Reddit user candiedbug points out: “At 43 terabits per second you could download Netflix’s entire 3.14 petabyte library in 9.7 minutes.”
4. Google Cardboard lets you experience virtual reality with stuff you already have -With some android software you can create your own virtual reality experience with things possibly lying around your home right now. All you need is some cardboard, Velcro strips, magnets and plastic lenses (and of course an Android device), and you can experience a 3D virtual reality available from numerous apps.
3. Wireless electricity is now a thing -Wireless electricity has been creeping into our lives with the likes of wireless charging smartphone docks where the handheld devices lay on top of a pad. Now, WiTricity have used resonant wireless power transfer technology to develop a commercially viable product that can charge your devices without the need of them being left on a pad. It also works through wood and metal.
2. SpaceX’s FALCON 9 reusable test vehicle reaches 1000m -Elon Musk dreams to colonize Mars in the future but this year his company achieved a milestone with their reusable rocket, reaching 1000m. At a time when budgeting for space sciences is at risk, the industry needs more efficient and less costly solutions to continue our exploration beyond our own planet.
1. Solar power can be generated in the dark -Researchers from MIT and Harvard have created a way for solar panels to absorb and store the energy from the sun’s radiation, which can then be used on demand to create heat.
However, do not forget that we landed on a comet! In my opinion that is the greatest engineering feat! Feel free to look into each one of these great engineering feats yourself!
LED Sign Example. Photo Credit: animationlibrary.com
Welcome back for another round of learning Arduino! I just want to take a moment to thank those who are continuing this journey with me. For those just joining us, please take a look at Part 1, Part 2, and Part 3 to clear up any questions! I personally have come a long way since my start in Summer and have worked on some really awesome projects this past quarter. Through the use of my personal Arduino starter kit, I have been able to build an obstacle avoiding car, a temperature controlling HVAC system, and a self-stabilizing wing. These projects were completed for a Control of Mechanical Systems class I took this past quarter and I can’t wait to share them all with you.
In Part 3, we were able to build a simple circuit and breakdown the code to control the circuit. It was a nice intro project that showed how to setup an Arduino code and upload it to the board. This time around the task will be slightly more involved but will show you important coding practices to make future projects more manageable. We will be controlling multiple LED’s and manipulating their states at any given time. Let’s get to it!
What you need:
8 x LED’s (any color)
8 x 330Ohm Resistors (if you don’t know what you have, the color code is orange-orange-brown)
Arduino board
Breadboard
Assorted Jumpers
Friendly Note: We are not responsible for any misuse or risky behavior!
Photo Credit: Vilros Starter Kit Guide by Sparkfun
Place the LED’s anywhere on the breadboard, without plugging any two legs into the same rows. This can cause a short and you will experience unwanted circuit behavior. Also, take care in knowing which leg is the longer length (positive) and the shorter length (negative). You may want to place the LED’s in an organized fashion so that the light sequencing looks nice. Remember, we want to place a resistor in series with the LED’s to protect them from excess current. Next, place jumpers from the positive LED legs to the Arduino inputs such as digital inputs 2 -9. Finally, apply a 5V potential to the positive(+) column on the breadboard and a ground jumper to the negative (-) column. Take a look above for a better view of the circuit layout!
Code
The code below is VERY good at teaching what each part does. Instead of re-analyzing each part again, I will add to it in hopes of clarifying any questions. Simply copy and paste it into your IDE and upload it to your Arduino board. I have included a video demonstration below the code to give you a better visual of what to expect once you run it.
// for tips on how to make random() even more random.
index = random(8); // pick a random number between 0 and 7
delayTime = 100;
digitalWrite(ledPins[index], HIGH); // turn LED on
delay(delayTime); // pause to slow down
digitalWrite(ledPins[index], LOW); // turn LED off
}
Video Demonstration:
Here’s what you should expect to see in your circuit! Enjoy!
In future projects you will most likely need to use For Loops and Arrays to complete tasks efficiently and to consolidate writing space. These components of code show up in all different forms of script such as VBA and Matlab so learning it now will make you better prepared. Have some fun with the code above by playing with the timing of delays and with the mixing of functions. If you’re wondering what multiple LED’s are even used for just imagine a marquee display. They are made up of a bunch of LED’s that turn on and off independently to form a desired letter, symbol, or shape.
Thanks for reading Part 4 of my Learning Arduino series and don’t forget to visit our GoFundMe site to help us reach our fundraising goal!
First off, contrary to what I stated in my previous post, today’s post will not discuss one way in which UUV technology is being optimized for the purpose of undersea warfare through the utilization of advanced biomimetics, as I ran out of time to prepare that post and thus will publish it in my next round of posts.
Today I will be sharing something a little bit different…the design of a full body suit that was recently worn by a man who was swallowed whole by a 25 ft. anaconda…on purpose. I’ll decline to comment on the validity of this kind of feat, as that is not what I am here to write about, but will rather focus on what is effectively a pretty interesting case study in engineering design.
Anytime something must be designed to be used by humans, the level of engineering required is almost immediately stepped up [for many reasons, including (but not limited to) the increased importance of safety], and this is no exception. In all product design, engineers must begin by determining the problem statement and the constraints imposed by that statement. Dr. Cynthia Bir (a biomedical engineer), one of the project leads for the suit design, would have begun by looking at the facts: there is a man, who will be ingested by an anaconda, and that man must then come back out of the anaconda without being harmed. As ridiculous as this must sound, it is actually quite reflective of the absurd nature of the design/operational constraints that engineers must often meet. Next, Dr. Bir would have had to conduct literary (or possibly even experimental) research into the aspects of the problem statement (the snake itself, and all aspects of the human-snake interaction to take place) and then determine/look at the consequences associated with this problem statement; that is, what are the specific risks posed to the user in this scenario (in this case: constriction, snake bite, and acid attack from the gastrointestinal acids). Next, she would have started in with generating concepts, selecting a few concepts to further develop, doing some base-line evaluation and analysis of those concepts in order to cut it down to one final design, and then starting in with the actual design/calculations/analysis/testing of her chosen design. I should note that engineering design is never this simple and is actually a very complex process, that generally sees many iterations and a great deal of looping back to earlier steps of the design process.
So, as we stated before, Dr. Bir had already deciphered the situation, conducted relevant research (how a snake attacks its prey, what kind of acids are present in the snake’s stomach, etc.), resolved the situation into the key parameters/constraints associated with the situation (ability to resist snake bite, constriction, and stomach acids), and now would have come up with a few concepts. Undoubtedly, one of the decisions that would have been made early on would revolve around what kind of material system to use in the design: one material for the entire suit or multiple materials used throughout the suit. In this case, it would have been very difficult to use one material for the entire suit, as the application calls for many different material properties (hardness, strength, and fracture toughness for the snake bite, stiffness and compressive strength for the constriction, and resistance to chemical attack for the acids, etc.) and thus it would be far more economical to use multiple materials (each one targeting a few key constraints) on the suit (as opposed to having to develop a whole new material to meet all of the specific needs of the suit). In fact, this is exactly what Dr. Bir and her team did.
The innermost layer of the suit actually served a different purpose: to monitor the vital signs of the man being swallowed (his heart rate, respiration rate, core body temperature, etc.), as if something began to go wrong, they would want to stop the experiment immediately. This layer consisted of a biometric vest that was paired through Bluetooth to the project team’s computers, giving them live updates of all of his vitals (it is interesting to note that these kinds of vests are also used by special operators, astronauts, some athletes during training, and many others).
Biometric vest. Photo Credit: Gizmodo.com
Next, came a thermal control layer in the way of a vest fitted with a pumped liquid cooling loop heat exchanger which essentially sends cold (colder than the man’s body temperature) water through small tubes that run across his body. The temperature difference between the man’s body and the water in the tubes drives heat transfer out of the man’s body into the tubes, thus cooling the man’s core temperature. This is important in order to make sure that the man does not overheat, because he will be wearing a number of thick layers of various materials and will be inside of the snake’s stomach so that he will be exposed to his own internal heat generation, the snake’s internal heat generation, and all of his insulating layers.
Water cooled vest. Photo Credit: Gizmodo.com
Next comes a chemical suit (not pictured) to provide the chemical resistance that we mentioned earlier. After this, a layer of chain mill (like that worn by Renaissance knights or people who dive with sharks) is added in order to block the snake bite.
Chain mill. Photo Credit: Gizmodo.com
On top of this comes a rigid carbon fiber shell that must be made custom to conform to the user’s torso and is used to resist damage to the ribs/chest cavity by constriction of the snake’s muscles. The torso shell was designed with a factor of safety of a little over 3 (meaning that the shell’s strength is over 3 times the stress that it will be subjected to during the event) and was tested by wrapping a thick rope around the shell and pulling the rope with tow trucks at either end.
On top of all of this, the user donned a thick layer of neoprene (think a wetsuit) to keep all of the other layers together and cover any otherwise unprotected parts of his body; this layer was then dusted with pig’s blood in order to attract the snake and ensure that the snake would actually want to ingest the man. Other things (a few of the many other things) that had to be considered in the design of this suit would have included the weight of each component, thickness (to ensure mobility of appendages), range of motion (note the fact that the torso shell is sleeveless), thermal conductivities of all materials (for proper heat transfer calculations), possible interference with the Bluetooth signal, ability to put on/take off the suit, and of course ability to breathe! The ability to breath is vastly secured by a combination of three things: the carbon fiber torso shell, none of the layers being too restrictive, and a sealed face mask (which also serves as eye/face protection from any objects or acids, thus the mask must also be chemical-resistant) with an external air hose (which must also be resistant to chemical infiltration) fed by an air supply from the project crew.
Face mask with air supply. Photo Credit: Gizmodo.com
Presumably leak-testing of the suit and air-supply lines. Photo Credit: aol.com
So there you have it, an interesting look at some of the engineering considerations behind one of the strangest things I have ever heard of anyone wanting to do. This just goes to show that the possible applications of the world of science, technology, engineering, and mathematics (STEM) are truly limitless!
Please be sure to check back Thursday for a Presentation post by Andrew and please remember to help us to share our fundraising campaign at GoFundMe.com/TeamUV
Although most people I know use mechanical pencils, traditional wooden pencils are still as important today as when they were first introduced. Wooden writing utensils are still used in compasses and colored pencils which means they will continue to need sharpening. Before receiving this prompt, I never realized how complex a simple wall or desk mounted sharpener really is. As a kid, I would utilize the class sharpener to avoid boring lessons or to talk to my friend but didn’t know the engineering involved to make such a device work. I’m not talking about an angled sharpener but rather a planetary sharpener like shown below:
Planetary Sharpener with External Case Removed. Photo Credit: Wikipedia.org
Planetary sharpeners installed in classrooms or offices in the 60’s can still be found in fully functional form. These things were designed to take abuse, misuse, and to stand the test of time. Taking a look at a mounted sharpener I was able to come to three engineering conclusions…
Planetary Sharpeners must be designed for ease of use
It’s safe to assume that a sharpener is going to be used by both adults and children at some point in its life cycle. This means that a designer needs to ensure that a child can apply sufficient force to crank the mechanism with ease. If this condition isn’t met then the market for such a product would become limited to adults working in office settings.
Material selection is key
As stated above, planetary sharpeners can be found in perfect working order even in run down and abandoned buildings who have gone years untouched. I attribute this to great material selection. Most sharpeners are manufactured out of steel which has been hardened to resist wear and deformation.
Planetary Gearset
Lastly, if you have ever taken the case off of a mounted sharpener, I’m sure you’ve seen the cutting cylinders used to sharpen. The internal mechanism is basically a planetary gearset. A sun gear is usually centered in the middle of the train with planet gears connecting it to an outer ring. This allows the center of the outer ring to revolve around the center of the inner ring or vice versa. In the case of a sharpener, the inner sun gear is replaced with the pencil and the connecting planetary gears are replaced with rotating cutting cylinders. These helical cylinders are designed to cut and are angled to form a point which also forms the point of a pencil. More information about planetary gears can be found here.
Planetary Gearset. Orange Sun Gear, 3x Teal Planetary Gears, and Blue Outer Ring Gear. Photo Credit: Reddit.com
Whether it be a door handle, a cup, or even a pencil sharpener, it’s sometimes easy to dismiss the complexity of our everyday products. The beauty of engineering is taking a complicated task and making it routinely easy for anyone to do.
Until next time!
To support the completion of our project please check out ourGoFundMesite and pass it along to your friends. We have already raised $500 and we couldn’t be more excited! Thanks everyone!
Photo rendering of a futuristic underwater robotic eel. Photo Credit: DefenseOne.com
While the vast majority of the attention with regards to unmanned vehicles is generally seized by unmanned aerial vehicles (or UAVs, which have almost become a household acronym in this day and age), the aerial environment is by no means the only one within which militaries benefit through the use of unmanned vehicles. In fact the same reasons that UAVs prove so valuable in the aerial environment (information gathering, reconnaissance, surveillance, unmanned combat, logistics support, etc.) also exist for UGVs (Unmanned Ground Vehicles) and UUVs (Unmanned Underwater/Undersea Vehicles…by the way do you realize that if you shorten UUV to UV, you get half of Team UV’s name? Rest assured this is no coincidence, our senior project aims to provide a stealthy, highly maneuverable ISR UUV, but we shorten it to UV – underwater vehicle – because with our compact size it would be impossible to man the vehicle, although UV is also an acronym for Unmanned Vehicle…plus “Team UV” is catchier than “Team UUV”…).
Click image for larger picture.
In the design of our UV, we are essentially optimizing the vehicle for ISR (Information/Intelligence, Surveillance, and Reconnaissance) type missions; we do this by providing for higher speeds, smoother maneuvering, increased stealth (on the fronts of thermal, magnetic, and flow signature, cavitation, noise, and overall inconspicuousness), and requiring little to no human interaction. All of these mission objectives that we have for our UV increase the vehicle’s performance and stealth, making it a much more efficient solution to be used by our troops to conduct naval ISR from a distance and thus, help to save lives. While our primary application is ISR, which directly serves the military, it is important to note that UUVs are not only used by the military, but are also used by harbor security, underwater inspection contractors, marine biologists, and even recreational users in some cases. The range of applications for UUVs has no end in sight, as can be seen by the small sampling of applications for UUVs listed below.
ISR: UUVs can be used (for example) to conduct reconnaissance (R) in order to obtain the necessary intelligence (I) (strategic, operational, or tactical) for effective military action and/or to provide maritime surveillance (S) of key areas along our coastline or to protect homeland ports.
Mine detection: In areas such as the Persian Gulf, UUVs have been used to detect and (in some cases) clear sea mines.
Underwater inspection: UUVs may be used to conduct underwater inspections of outfalls, pipelines, or other underwater structures that may be too deep, dangerous, or inconvenient for humans to inspect.
Exploration: UUVs have also been used extensively by scientists, filmmakers, and even recreational users to explore the underwater habitat.
Underwater mapping: UUVs are used by the military and some other governmental agencies to map the sea floor.
Collection of weather data: The military also uses UUVs in order to collect data with regards to weather, subsea currents, faultline activity, and other related subjects. (While a little off topic, it is interesting to note that the military actually has a huge presence in the field of weather sciences and the USAF actually has a squadron – the 53rd Weather Reconnaissance Squadron – that flies directly into hurricanes and tropical storms, armed with loads of sensors for data collection!)
Object recovery: UUVs are used in recovery of sunken items from depths traditionally seen as unreachable by humans (in recent news, the US Navy’s Bluefin-21 drone has been used extensively in the search for the downed Malaysian MH370 plane; UUVs have also famously been used to recover items from historic shipwrecks).
Force/area protection: UUVs could also be used to thwart undersea attacks and help to safeguard our troops as well as key areas (i.e. harbors).
Attack missions: Lastly, UUVs could also be used in the opposite capacity by going on the offensive.
U.S. Navy Bluefin-21 drone (left) and TPL-25 (Towed Pinger Locator). Photo Credit: wsj.net; telegraph.co.uk
As more conflicts arise and scientists and engineers continue to push the boundaries of technology, the role of UUVs in undersea warfare is only set to increase; this is especially true when budgetary considerations are taken into account in that the cost of a small UUV is almost negligible in comparison to a full-scale submarine. This is not to say that a UUV can replace a full-scale submarine, nor that they even share the same roles; however, as submarine fleets diminish due to the astronomical costs associated with initial acquisition and subsequent maintenance, the number of UUVs used by the military will only continue to rise. When you pair this with the fact that, as the current UUV technology becomes older and less expensive, more and more groups (whether for better or worse) will have access to UUVs, the reason that further developing UUV technology is of such great interest to the defense industry becomes more and more apparent.
Hopefully this post served as a helpful primer on unmanned drone technology and the role(s) that UUVs play in the defense (and other) industry(industries). This upcoming Tuesday (12-16), I will be continuing off this post with a Well Read post discussing one way in which UUV technology is being optimized for the purpose of undersea warfare through the utilization of advanced biomimetics (that is, by mimicking the various ways by which fish swim!). Be sure to check back Sunday for an Open Mind post form Andrew and please continue to help us to share our fundraising efforts at GoFundMe.com/TeamUV
