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Engineering Fields and Careers - Mechanical Engineering
In this class, I sympathized for the professor who was introducing ME to us because it is not an easy task. Mechanical Engineering is one of the oldest and broadest disciplines. We have all heard of the story about cavemen inventing the wheel. Those cavemen can be considered as some of the earliest engineers. ME is an aggregate of physics, materials science, manufacturing, maintenance of systems, mechanics, kinematics, thermodynamics, structural analysis, and electricity. My point is this: there is not one set direction that ME majors need to take. An ME major has the freedom to choose from many different possible career paths, unlike many other fields.
During our module, our professor gave out the same machine to 5 groups of 4 people. Each group was told to first analyze and draw the machine, and then take it apart with the tools provided. This is similar to what was given to us:
The first though that came to mind for most of the groups was a motor, specifically a hydraulic motor because of the two openings on the sides of the machine. No one was able to guess the correct identification of our mystery device, so our professor told us that it was a gear pump. The gear pump takes in a low pressure liquid and forces it out with a high pressure.
Although this is a simple device that is often used for lubrication or hydraulic machinery, it taught a very important lesson about mechanical engineering. This demo taught me that mechanical engineers first have a larger goal, which is analogous to having to identify what the machine does/is. Then the MEs need to develop a working system that can perform its function over and over. This includes finding stress points, using durable materials that won't ware another down, considering energy and thermodynamics, and understanding the limits of the structure. For anyone that has designed and tested a working device, they know completing a project can be a very rewarding feeling. Imagine doing that for a living!
To summarize, mechanical engineers deal with almost anything and everything. ME majors are taught to look at machines in a different way, and often have a large curiosity for how things work.
Engineering Fields and Careers - Civil Engineering
Hey everyone, sorry for the lack of posts lately... I have returned home from my Stevens program, and I already miss it! I will continue to post about the different classes and labs I had during the program even though I am not still there because there is a lot to know about the different fields of engineering!
Coming into this class, I was expecting Civil Engineering to be one of my least favorite fields. I thought it was a lot of highway construction and road maintenance. Civil Engineering actually became one of my favorite classes of the entire program. I learned that there is much more interesting things to civil than just roads. One of the first main points of our professor was that nature inspires civil engineers. For example, trees are relatively flexible and can withstand large amounts of vibrations/forces before collapsing. This showed engineers that by using rigid materials one would create more pressure and stress points on a structure. Engineers look to nature because on paper a structure may look very promising, but if the specific conditions of where the structure will be placed aren't met, then creating it would be a waste of time and money. For example, the Akashi Kaikyo bridge in Japan was engineered to withstand earthquakes.
Instead of lodging the support towers deep into the ground, the engineers placed the supports on top of the ground underwater. The forces during an earthquake are mainly horizontal, so this bridge actually acts like a skateboard or roller blade and slides back and forth when put under stress. During the Great Hanshin Earthquake, which had a magnitude of 6.8, the Akashi Kaikyo bridge was able to withstand the force while, sadly, other structures could not.
Pretty cool stuff! It gets better. Engineers also used nature by understanding the qualities of a circle. The "perfect arch" in engineering is actually just a semi circle. This wasn't a recent discovery either. Dating back to 700 BC, the ancient roman civilization was utilizing the power of the semicircle. Here are just some examples when it was used:
The PantheonThe Colosseum The Pont Du Gard aqueduct
The reason that these structures were able to withstand millenniums of weathering and use is because of the design. The semicircle is special because it allows all of the pressure points to have forces going either straight up or straight down.
Here is a throwback to physics. Imagine a truck parked at the center of this bridge in Venice, Italy. Since it is at rest, the only forces acting on it are gravity and the force of the bridge pushing back on it. The downward force of gravity needs to be countered by the upward force because of Newton's third law. Here are pictures of the forces on a truck sitting on a bridge as seen above vs. a truck sitting on a semicircle structure:
As you can see, it will require more force to keep the truck stationary on the first bridge than on the semi circle. The semi-circle would be much sturdier than the bridge in Venice because there are more pressure points on the structure that has such a low angle. There are thousands of pounds of concrete reinforcing the foundation of that bridge because the architect knew the bridge would experience lots of horizontal force with that angle. In the class, we were given time to build a bridge using bricks and cardboard to see if where a collapse would happen with a bridge with that angle. I took a slow motion video of our bridge collapsing after we added weight to it. If you look closely on the left hand side, you can see the wooden block that was nailed into the board rip up and fail:
I hope this post opened up your thinking to civil a little bit, and makes you think about the different designs and structures you encounter everyday. Hope you all are enjoying summer! Stay tuned for more engineering sub-disciplines!
Engineering Fields and Careers - Biomedical Engineering
In this post I will be talking about both the class I took for biomedical engineering and the breakout/short lesson on spinal injuries and implants.
In the class, we first learned how to use electromyography to understand how the eye works.
We found that the eye has a difference in electric potential between the front and back of the eye and therefore causes a current when contracting the muscles that move the eye in all different directions. This technology is important to the biomedical field because it helps optometrists identify if there is something wrong with muscles in the eye or if the retina is not working correctly. Although my friend looked pretty upset in that photo, he had a great time following laser pointers to help us collect data!
Later in the outreach we learned a bit about how blood pressure is measured. Systolic blood pressure is the pressure when your heart is actually pumping blood, and diastolic blood pressure is the pressure when your heart is resting between beats. 120 mmHg is normal for systolic, and 80 mmHg is normal for diastolic. The way that your doctor typically measures your blood pressure is by creating a pressure slightly above 120 mmHg so that your blood circulation is cut off. (Note: doctors should do this on the vessel in your left arm because it is closer to the heart!) Your doctor will then slowly release the pressure in the cuff and listen for the first beat of blood and mark down the pressure. Then when it gets lower your doctor will note the pressure of where the last beat was heard. Not too complicated stuff, but it was interesting nonetheless!
For the breakout/mini lesson our professors focused more on implants and importance of materials. Four main things are taken into account when creating a implant - biological conditions, response, material properties, and cost. Most materials will not be accepted by our body, so the implants must be created with special composites that often cost lots of money!
The two different implants in the photos above were around $10,000 each! Both of them are spinal disk replacements. In between each of the vertebra in our backs are cartilage disks that cannot regenerate. Both used to replace a herniated disk or osteoporosis by creating more space between vertebra.
The claw looking device I was holding up is used for removing cartilage disks that are damaged. As you can see in the other photo, our spines need to be a certain distance apart so our spinal chord stays protected. Over time when our cartilage disks get worn down, the vertebra get closer and closer, potentially damaging nerves. The cylindrical cage is used to actually grow bone in place of the cartilage. This is called a spinal fusion. This surgery is effective in creating space between vertebra, but also limits one's mobility. That is why the other piece was invented. The top half can rotate and move around on a ball and socket type joint, allowing a greater range of motion. The reason I am talking about this exercise so much is because I am interested in pursuing biomedical engineering in my future studies. A big problem with these devices is that they are never permanent fixes and often have bad side effects. Imagine you put metal rods in your back because two of your vertebra were too close. What happens is all the bone and muscles under that implant weaken and deteriorate because the metal is doing too much work. That made me think, "Why not just use a composite that is similar to the strength of bone?". Apparently the answer isn't as easy as the question implies. Biomedical engineering is a very fast growing field, and with the advances in computer programs and material sciences I hope to one day answer questions like that!
Some cool stuff: we were able to dissect a pig's spine and find nerve chords and cartilage disks.
The last thing our professors showed us was how to shock neurons in our arms to make our muscles contract and "hit the whip"!
I hope this was informative enough and if you have any questions, don't be afraid to ask! More to come on different fields of engineering, so stay tuned!
Engineering at Stevens - Research Project
Hey guys! For those of you who don't know me, I am Jake, an upcoming senior, and am very passionate about science and math. I will keep the intro brief. I am currently studying at an engineering program at Stevens Institute of Technology! It is in Hoboken, New Jersey, and right across the river from Manhattan. Here are pictures of the view and my friend:
This program is meant to give high schoolers hands on experience with different fields of engineering and professors, so it is not very specific, but very informative. I thought it would be a good idea to post about my stay here because, personally, I didn't know much about each sub-discipline of engineering until this camp, so I want to help others out who may not know!
I just finished my research project on chemical biology, so I wanted to post about it. I worked with a professor on three different projects - bacterial transformations, antibiotic sensitivity, and gram staining/bacteria identification.
In the photos seen above we changed the DNA of the bacteria, E. Coli. We wanted to test if by inserting a plasmid (code of DNA) with genes that encoded bio-luminescence and ampicillin resistance (antibiotic resistance) we could change the structure of the bacteria's DNA. The reason we used bacteria and not a eukaryotic cell is because it does not have a nuclear membrane protecting the genetic information, meaning we only have to break one membrane to insert the plasmid. It was a very fun experiment and the results were very rewarding, even though I had some close encounters with E.Coli!
Our next experiment was antibiotic sensitivity. It was simple but also fun. We placed small disks of antibiotics on Petri dishes that had a growth medium with either E. Coli or Bacillus Cereus (bacteria) mixed in. After 2 days, we measured the zone of inhibition or zone of anti microbial activity to determine the strength of the antibiotic against each bacteria. We used 4 different antibiotics that were meant to inhibit or stop the formation of the cell membrane. We found that overall the E. Coli was affected less by antibiotics than Bacillus Cereus. This is because E. Coli have a more complex structure to their membrane! Sorry for no pictures!
Our final experiment was bacteria identification/gram staining. Gram staining is a way for scientists to distinguish between types of bacteria based on the components of the cell walls. There is gram negative which constitutes a pink stain, and gram positive which results in a blue stain. We placed 3 different types of bacteria on 3 different growth mediums to see if they would hydrolyze the substances.
For those of you who haven't taken bio, hydrolysis is the breakdown of larger molecules into smaller ones through the addition of water. Bacteria use hydrolysis (if they have the correct enzymes) so that they can use the smaller products that are created. As seen in the photos, some bacteria have the necessary enzymes to break down the growth mediums, while others cannot.
After all of the experiments were complete, we had to write a research paper on the gram staining lab. It was not as daunting as the lab reports in AP bio! (Joking) I was able to learn a lot more about the Chemical Biology aspect of science in this project and some specifics about biology along the way. It is a lot of hands on experience, and trial and error. As my professor explained, it is important to understand the chemical concepts that are applied in the lab, especially for a chemical biologist. For those of you wondering, chemical biology is different than biochemistry, and is more the application of chemistry to solve biological problems. Overall it was a very intriguing, and opened my eye to a career I didn't even know existed before!
More to come on engineering sub disciplines!
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