SCI 184

Our science class this past week was lucky enough to given the opportunity to listen to Prof Tom Vales of the engineering department tell us about different ways to generate power that have surprisingly been around for centuries, and even more surprising are still used to day.

The first example he gave us was the Peltier effect.

A small portion of history first (as always): This was named after French Physicist, Jean-Charles Peltier. He was born in France in 1785, and his most famous contribution to this day remains the Peltier effect.

The process of it is very simple. Peltier realized that if he ran the electric current through two different metals, he could create electricity. This is how he physically demonstrated it to us. Using a fan with two separate legs (each having a different metal), he placed each side into a cup of water, one hot and one cold. This caused an electric current to flow, and the fan began to spin. This type of effect is used today to heat or cool drinks, a mini fridge. Unfortunately, it only has 10% efficiency, making it impractical on the large scale.

 

Jean-Charles Peltier

 

The next engine displayed on a small scale was the Stirling engine. It was invented in 1816, by Robert Stirling. Stirling was of Scottish descent from a large family. He initially studied Ministry at the University of Edinburgh and became a minister for the Church of Scotland. He was always interesting in engineering and to this day his most famous discoveries continues to be the Stirling Engine.

It is similar to the steam engine but less dangerous and more efficient, with up to 60% efficiency. The Stirling Engine, unlike the steam engine is very quiet and runs off hot water and hot air, the moving air moves the engine up and down, creating energy. The only stipulation was that there had to be a 4degree celsius difference between the water and the air.

Here’s a very basic picture of a handheld Stirling Engine. One of their main advantages is that they have the compatibility to be used as heaters during the winter and coolers during the summer.

 

 

 

The next type that was shown to us was a simple barbecue lighter, an invention that we today take for granted: the Barbecue Lighter. The concept used in the everyday barbecue lighter does a lot more than we probably realized. It

went from a mechanical to electric light, with a small piece of quartz as a spark mechanism. This same type of concept is used in many everyday appliances from everything to lawn mowers to radio frequencies.

All of these concepts he showed us were extremely logical, once we had been exposed to the idea. Even though most had been invented centuries ago, they are still the basis of many new advancements in technology.

 

The final part of his presentation was probably the most exciting, and the part I understood the least. Coming from the Serbian-American Nikola Tesla, was the Alternating Current Power System.

Here is the handsome Tesla. He was the first one to introduce the idea of wireless electricity into homes. Tom Vales demonstrated this one as well. Tesla’s idea in a modern form consisted of a bucket with coils of special coated wire around it that once a current was put through it, produced enough energy to light up a light. We turned off the light, and Tom Vales held a stick that began glowing in two different colors, because it was filled with Argon gas. He demonstrated the same process with a light bulb, even allowing the electric current to run through his body.

Tesla’s idea was to make one of these available in every household, the only problem is that the range was too short, and to power an entire house a large amount of energy would be  needed, at a potentially dangerous voltage.

 

The entire presentation was very enlightening and it was interesting to see these complex ideas on a small and understandable scale.

 

 It’s interesting to think that our hands have the capability to generate tangible energy. I suppose when you think about it logically, it makes sense, but to see what happens when our hands are put to use is actually amazing.

Today we learned about Faraday’s Law of Induction, something that was an entirely new concept to me. Before I introduce the law, I’ll go into a little background of the man brought this idea into society, which I personally believe is essential into fully grasping the law itself.

  Michael Farady was born in 1791 in England     and surprisingly enough recieved very little  formal education, mostly everything was self taught. His family was that of the lower class, so paid education was not an option. Faraday aquired most of his knowledge through different apprenticeships throughout his youth, beginning at age 14. Although by the end of his life, Oxford University granted him an honarary Doctor of Civil Law Degree. Faraday was a humble man, and rejected knighthood and the position as President of the Royal Society (of England)

In his adult life he established himself through his discoveries in the world of chemistry, physics, diamagnetism, and electricity which created a strong foundation of these areas, most of which are still used today.

As I mentioned before, the specific law of his that we are using (and arguably the most famous) is called Faraday’s Law of Induction.

The simple definition used in our experiment is:

“Generation of magnetic flux through coils of wire to generate electricity”
 This lab was relatively simple but complex at the same time. This brings me back to what I was saying before about our hands: our hand movement was the catalyst in the creation of electricity. Let me explain.

Process: We were equipped with what looked like an ordinary flashlight, except there was a a magnet inside, that moved along the base of the flashlight when shaken. The coils of wire inside, plus the magnet, and the movement of the flashlight produced electricity.

Goal: We wanted to see how much electricity was produced as well as the correspondence of shakes for every 30 seconds. Using the program LabView as well as our Mindstorm robots, we were able to accomplish this.

The flashlight was connected to the Lego Mindstorm robots, which in turn was connected via USB to the computer in LabView, and Labview was in turn connected to an Excel spreadsheet which would document our results.

We were supposed to collect 5 different results, at 30 second intervals each, the first test shaking the flashlight back and forth the slowest, and the 5th interval shaking the fastest. Heres a short table of what our results looked like.

Results:

# of Shakes      Voltage Squared (all at 30 second intervals, the constant)

0 shakes             .056532

23 Shakes          13.5308

33 shakes           14. 9879

80 Shakes          99.4786

92 shakes           155.6630

You can see how each time the more shakes added, created more voltage, which was to be expected.

If we were to look at this in a graph for, we could visibly see a scatterplot with a line drawn through that steadily increased with the number of shakes per 30 seconds.

I personally enjoyed this lab because it displayed that handheld devices for the home, have the potential to be equipped with these small type of generators that would allow to replace batteries, which ultimetely harm the environment as well as save electricity by making it ourselves.

Even for those who are not science orientated, the discussion of renewable and sustainable energy sources is universal- a theme that has a lot of pertinence to this day and age. First to make the definition clear, there is a slight difference between the terms, renewable and sustainable energy sources, which are often used interchangeably.

The term renewable Energy refers to an energy source that cannot be depleted or completely exhausted, whereas the term sustainable is very similar to renewable but it simply refers to the different economic and social issues to using renewable sources.

There are many different types of renewable resources that could potentially be harnessed at a magnitude that could eradicate all the world’s energy problems. One of theses sources which is on the rise, is the use of Solar energy  or Photovoltaics.  One impressive figure: if we covered an area the size of Nevada with solar panels, there would be enough energy harnessed to power the entire United States. Although this seems almost too good to be true, this goal has many obstacles. Many are against solar plants (this is also true for wind turbines) because of their perhaps less than natural appearance. Many governmental regulations as well as communal hesitation and the expense,  slow the development of solar energy “farms.”

A few electric facts about solar energy:

Solar energy generated constant electricity or direct current. Most household appliances run on AC, alternating current, which means that the photovoltaics need a inverter to change the photovoltaics into alternating current.

-The term “light intensity” (what we measured for the experiment) is simply the measure of the energy of light. The higher the intensity logically means the more photons are generated equalling a greater current and voltage.

*The speed of light is measured at c=3 x 10 to the 8th power m/s.

A solar panel is made from silicon. Silicon is a semi-conducter, meaning it is partly an insulator of electricity as well as partly a conductor.

Experiment:

With solar energy in mind and these facts in mind, we conducted an experiment of our own to really grasp the amount of energy a single solar panel could produce.

We were given our own small, “handheld” solar panel , roughly the size of the palm of a hand and a flashlight. Using our lego robots, connected to the program, Labview.  Our task was to measure the amount of energy produced at different distances from the flashlight to the solar panel.

With the flashlight off, the amount, the amount of voltage measured was : .017384 watts

0 distance: .42662 watts

(solar panel held:) 2 inches away: .39587

3 inches away: .324022

5 inches away: .30990

7 inches away: .229394

As indicated by the numbers, the farther the solar panel was away from the flashlight, the less energy was produced.

Here’s a graph: Lab

The seoond part of the experiment was to see how the energy changed when putting different color filters over the flashlight and see how that affected the amount of energy.

The first filter we tried was

Light Blue: with a voltage (at zero distance) was .396

meaning that the light blue did not really adversely affect the amount of light produced. The voltage was similar to when the solar panel was held 2 inches away from the flashlight.

Pink: voltage measured was .324, similar to when the panel was held 3 inches away from the flashlight.

and finally

Dark Blue:  voltage measured was .310, similar to when the was held 5 inches away from the flashlight.

 

Conclusion: This experiment really demonstrated how much energy can be captured, even in the form of a handheld device.  Even though solar cells max out at around 23% efficiency, it is still a form of energy that with modern day technology becoming easier to produce, and produces no greenhouse gases; way better for the environment!

I was surprisingly excited for a science field trip. It’s not everyday you can say you’re going to visit a nuclear reactor, but that’s exactly what we did on our Monday afternoon.

After a semi-stressful T ride, and only one stop later, there we were getting off at Kendall/MIT stop mid-afternoon on a sunny day in October. I had never been to that part of Cambridge before and was relatively content with our surroundings. We arrived at the reactor site and were greeted by a friendly guide who began to give us the run down. (Although I had not voiced my concern outloud, he dispelled my fears of contracted cancer from the radioactivity found in the center).

We had to sign in our names and were given a personal Geiger counter to use to measure our the amount of radioactivity we came in contact with. The number on each individual Geiger counter was taken at the beginning of our tour and recorded, be compared to the reading after. As we all amusingly and interestingly figured out this new equipment, we began our overview.

The first order of business was to understand what exactly radiation was, and the difference between radiation and contamination.

Radiation refers to the process of which particles move throughout a space. Contamination on the other hand is the negative form, basically radiation where you don’t want it. As our tour guide eloquently said it, it is “radioactive dirt.”

Facts about the MIT reactor:

-It has been in operation since 1958

-2nd largest university reactor in the country after The University of Missouri Research Center

-Used for research only, not to provide nuclear energy.

– has been the home of a progressive treatment of brain cancer, as a way to use the radioactivity to help kill the cancer cells in terminal cancer patients.

-powered by Highly Enriched Uranium but in the process of transferring to low.

Here is a picture of the interior of the nuclear reactor.

 

 

 

 

– used mainly for the observation of neutrons and radiation for research purposes

-there are 6 boron/cadmium rods which are use to either slow down or speed up the reaction. To slow down the fission/fusion, the rods are placed inside the reactor in order for the boron to absorb photons. The rods are removed to speed up the process.

-the plant uses 2200 galloons of cooling water/min to keep the temperatures in check

 

With these puzzling new facts swimming around my head, we concluded our introduction and proceeded into the high security area of the reactor. As we entered the actual room that housed the reactor, I was struck by the antiqued look of the technology. And with this thought, the guide began to explain the complexities of each switch and machine, when I realized that it was more technological than anything I had ever seen.

He showed us the radioactive barrels, one which was affectionately called Moby Dick as we made our way to the control room.

As the picture shows, the walls are lined with features that the    technician has to be familiar to ensure that the reactor is properly  monitored and in the case of an emergency. We quietly stood there in  awe at the complicated wonder of science and exited slowly, almost  unwilling to leave.

 

 

This concluded our quick but concise tour. But before we could exit the restricted area, we had to test our hands and feet for radioactivity in case we had accidentally been contaminated. Luckily we were all “clean” as the machine told us and exited successfully.

Seeing the MIT reactor, I was able to visually understand better what happened during a nuclear reaction, where it took place, and how it was controlled.

I was captivated during class as we were presented with historical information, a quick introduction to the household names of Galileo and Sir Isaac Newton. Galileo (1564-1642) is most notable and immortalized for his role in the Scientific Revolution, his contributions to astronomy, and as one of the first to experiment with moving objects. His name has been down in history and is considered by many to be the “Father of Modern Science.”  Here is the most famous portrait of Galileo.

With Galileo’s death came the birth of Sir Isaac Newton in 1642. Many argue that  Sir Isaac Newton is THE greatest scientist of all time. I’m sure that depends on your scale of greatness, into how the term is operationalized, etc etc..but nonetheless his discoveries are used as the basis today of inertia and motion.

Sir Isaac Newton’s law of Inertia: An object will  remain at rest or in Uniform motion in a straight  line, unless acted on by an external or unbalanced  force  (contrary to Aristotle, who that the natural  state of the object was at rest)

With this information and a few more formulas involving work and force, we applied this newfound knowledge to our Mindstorm robots. Knowing that:

Force = Mass x Acceleration                                                                         and

Work = Force x Distance (work must equal a change in location)    and

Power = Work / Time                                                                                      and

1kg on Earth (force of gravity) = 9.8 N                                                       and

understanding the differences in kinetic vs potential energy,

we could apply this in a lab form to test our robots.

We were going to do two different experiments. A pulley system was set up and attached to the robot, with a place to attach weights. The robot, when connect via USB to the computer had the capacity to use force to pull the weight up. Our goal was to see how the acceleration changes (basically how fast the robot pulls up the weight) in two different cases.

1. We would keep a fixed force, but change the mass (using F = m x a)

2. We would keep a fixed mass, while changing the force.

We ran three trials for each test: Fixed force

Power level/force: 75.

Trial 1: Power force 75 = .25 kg (mass) x a

Trial 2: 75 = .23 kg x a        

Trial 3.   75 = .19 x a

Hollywood had done its job: A-list actors, such as Kate Winslet, Jude Law, and Matt Damon, star in a modern zombie-like-film depicting a series of events after a highly contagious unidentified disease is released onto society. A breakdown of the norm-individuals are reverted back to their primal instincts of survival in a manifestation that happened too quickly to be believable. As always, you find yourself unwillingly roped into the unrealistic unfolding of events. But how unrealistic are they?

First of all, a few key “facts” concerning the movie should be referenced before we go on further discussing the believability. The fictional virus, the MEV-1 virus, sprouting from the mixing of bat and pig, attacks the respiratory and then the nervous systems. The CDC describes it of having an Rnot factor of 4 (the number of people on average an infected person gets sick) By the end of the film, the disease kills 1 in 5 people and has spread to the remote corners of the earth.  In news reports about the movie, scientists are quoted as saying the scenario is plausible. But is that true?

In an article by the Huffington Post with the misleading title of “Contagion is Real, According to Scientists,” scientists say it is plausible. But plausible is as far as it goes. Although the props must be given to the director and all those who worked on the movie, because many details remain accurate. The chances of any contagious disease spreading quickly to even remote regions is extremely high, in the 21st century, mostly because of the amount of traveling that is conducted on a daily basis. Many scientists and employees of the CDC worked closely with the film makers to maintain as much scientific accuracy as possible.

In another article by W. Ian Lipkin, professor epidemiology and a professor of neurology and pathology at Columbia University, titled “The Real Threat of ‘Contagion’” published by the New York Times, says that more than three fourths of all newly contagious diseases have jumped from wildlife to humans. In a world that has increasingly globalized food markets, the spreading of disease from one corner to another corner of the planet is highly efficient and plausible. He also points out that this can be seen as a commentary on the underfunding and understaffing of our nation’s (US in particular) health system. That ultimately if we are faced with an outbreak of something so massive and destructive, the real reason to panic would be the state that the system would find itself in after only a few days of strain.

The other unrealistic detail of the movie was the speed at which a vaccine was tested and distributed amongst the populations. This is the portion that most scientists and critics agree was the most unfathomable portion of the movie.

Overall the movie’s entertainment value is there-if your into 21st century realistic-like zombie movies. But overall the acting was rather week, and too many loose ends for my taste. A good lazy Sunday afternoon film, if you go into with that mindset, you will come out relatively pleased.

Contagion Movie Trailer

 

For an interesting article on the CDC, click here

http://www.cdcfoundation.org/content/how-cdc-saves-lives-controlling-real-global-disease-outbreaks

http://www.huffingtonpost.com/2011/09/15/contagion-is-real_n_963898.html

 

Robotics made easy?

I never thought I would find myself experimenting with robots. Technology and games were never really mt thing, and I left those to my younger brothers to dabble in. But here I was, in Science 184, building a robot, sin lab partner and having a surprisingly good time. After assembling the robot, we were supposed to put him to the test.

Connected through a USB port, the robot was running through a program called “Labview.” Using labview, our task was to run a simple experiment using different amounts of power to measure the distance and the velocity the robot would go, measure his physical distance travelled (therefore finding the velocity) and compare it to the results that Labview found. Once our trials were over, we had to consider the difference in measurements found by us vs. the measurements found on Labview, which are in theory more accurate.

Using the different measurements, we needed to calculate our percentage of error- basically how far off our measurements were compared to Labview’s, the actual distance/velocity.

We had the measure, with a ruler, the starting point of the back wheel of the robot, and then how far the back wheel had moved by the end of the trial. We were measuring the distance between Point A-B.

So here’s can example of the first trial:

Time: 1 Second (how long the robot travelled for)

Power setting (how much power the computer was programmed to give the robot): 75

Distance measured (how far the robot traveled in cm, according to my measurement): .26 cm

Velocity measured (“   “): .26 cm

etc, etc-below, the rest of the results from the trials are graphically illustrated.

My percentage of error on all three of the trials was between 5-6%. But the question is why was there a percentage area at all? There many reasons why the results that I came up with would differentiate from Labview’s. Perhaps each time, when I took the measurement of the starting point, maybe it wasn’t directly on 0, instead more like .5 or 1cm, which ultimately would throw off the data.

 

Here is the physical representation of the data….

 

robotics made easy

 

 

“Fukushima is the biggest industrial catastrophe in the history of mankind,” Arnold Gundersen

The full name, Fukushima Daiichi nuclear disaster, is hardly pronounceable to us Westerners, but its impact is not diminished. On March 11, 2011, the world experienced Chernobyl, 21st century style. Following a tsunami caused by an earthquake in Japan, the result was a nuclear meltdown, that grasped the worlds undivided attention. For those of us in generation Y who are too young to remember Chernobyl, this event was unparalleled in our history.
The magnitude 9 earthquake (in the top 5 most powerful recorded) coupled by the tsunami, created enough devastation, but the added nuclear meltdown was a cause for even more heartbreak. The plant, owned by the Tokyo Electric Power Company, experienced the meaning of meltdown. Plant flooded, and by day two, reactors 1,2,3  were destroyed, leaving reactor 2 a completely melted. Radiation exposure expanded to a 20 mile radius around the plant directly after the incident, with many plant workers exposed to radiation. This radius was edited a few days after, with levels of radiation high enough reaching as far as 50 miles away. A total of 200,000 people in the immediate area were evacuated, according to the IAEA (International Atomic Energy Agency) and Japan reported the accident as a level 4 on the International Nuclear and Radiological Event Scale (INES), meaning an “accident with local consequences” despite many nuclear organizations beliefs the number should be higher. (The scale tips off at 7 “major accident”.)

The consequences of this disaster are severe-the environmental damage,  displaced  population, and another reason for skeptics of nuclear energy as a  source of power.  The society is also permanently altered. People are now  walking around with masks,  tap water is undrinkable, parents could not buy  their young children fresh produce,  and umbrellas must be carried to  protect  fromt the contaminated “black rain”-all  flashbacks to the aftermath of the  bombing of Hiroshima in 1945. According to an  article in the Guardian  called “Fukushima disaster: it’s not over yet” by Jonathon  Watts, a deep  mistrust in the Japanese government is now permeating society. A  Japanese  mother and friend of Watts stated, “We are misinformed…Our problem is in  society. We have to fight against it. And it seems as hard as the fight against those reactors.” 20,000 people already perished due to the earthquake and tsunami, how many more lives will this disaster claim? Families are now being forced to move-but perhaps the greatest difficulty is for the ones that stay. They have to be extremely careful about their food choices about which schools they send their children too…their worries seem endless. The psychological and physical effects of a disaster such as this are terrifying- the survivors can develop many forms of cancer, insomnia, post traumatic stress disorder, as well as a dependency on alcohol and depression. Each day the news confirms these effects. Only the future will tell what is in store. Hopefully in the meantime, we will work towards prevention.

 

 

 

 

 

An example of new consumer worries-make sure their food is not contaminated

 

 

 

 

 

 

A picture doesn’t do justice-a small physical image of the damage

 

http://english.aljazeera.net/indepth/features/2011/06/201161664828302638.html

http://www.guardian.co.uk/world/2011/sep/09/fukushima-japan-nuclear-disaster-aftermath

http://www.iaea.org/newscenter/news/tsunamiupdate01.html

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