As a class trip, we visited the Massachusetts Institute of Technology Nuclear Reactor Laboratory (MIT-NRL). The MIT-NRL houses and operates a 5 megawatt (MW) nuclear reactor (MITR) which runs at 50°C (the temperature of hot bath water). Currently the reactor is the second largest university reactor in the entire country but don’t let this fool you – it’s still small enough to fit inside a hug (though I wouldn’t recommend doing so). According to the MIT-NRL, the MITR is “a light-water cooled and moderated, heavy-water reflected nuclear reactor that utilizes flat, plate-type finned, aluminum clad fuel elements.” From what I learned, the reactor has more security than Obama that not only protect it from being taken out but also help keep any contaminants in. To spare ourselves of further details that neither of us will understand I’ll put it simply: The reactor is not used to generate any electricity but rather it produces neurons that scientists and researchers use in their studies. Even if it was used to generate electricity, after all of the power lost in transmission of energy, its 5 MW capacity would only be able to power a bunch of light bulbs.
(Models of the MITR)
Starting our tour of MIT-NRL was like something out of a Bond movie. We had to leave all of our belongings behind and have our starting radiation levels tested to measure any hazardous changes to it when we came out. We then went through one security door and two sets of blast proof doors before entering into the steel box containment building where the MITR is held.
Then we were shown around. We learned that the MIT-NRL used to conduct research on humans, specifically though with tumors. This is a form of therapy called Baron Neutron Capture Therapy (BNCT). Patients used to be held in a room under the reactor and scientists could use what I interpreted as a ray gun to target the tumor wherever it was, usually in the brain.
Now if the MIT-NRL conducts such studies humans are no longer involved and lab mice are used as a substitute.
We were lead down to the control room where someone must always be present to check for any abnormalities in the neutron flux levels of the MITR. Most of the controls are analog because of resistance from head organization to make the switch to digital. Their resistance is based on many things like being more able to control analog but mostly it’s just unwillingness to make changes. I say this because between the two, digital is more accurate, quicker, and easier to use.
As someone coming in with very little knowledge, I imagined what it’s like to be in a control room when something went wrong. Surrounded by all of those different buttons and controls and light flashing I think I would look something like this
When the tour was finished we were lead back out through the blast proof doors and each of us had to stand on a contamination monitor which looked like a robot to make sure we were “clean” of any contaminants we may have been exposed to.
(Contamination Monitor)
All in all it was an interesting trip and I learned a lot about nuclear reactors. It was good to get some hands on (not literally since we couldn’t touch anything) knowledge about all we’ve been learning.
Many nations are revitalizing efforts towards cleaner energy, namely solar power. Here is a brief look at what’s being done all over the globe to develop and implement solar energy resources.
The United States is working hard to put more into its solar energy efforts and growth in solar energy is beginning to take off in the nation. New technologies have been pivotal to this growth and companies are continuing to force the costs of this energy down so much so that some say the prices of this clean energy can compete with those made from fossil fuels. The solar resources in the American southwest including, Arizona, California, Colorado, Nevada, New Mexico, and Utah are among the best in the world for large-scale solar power plants. Projects for solar energy production are largely focused in these areas for their high levels of direct normal insolation of sunlight.
Recently developed in India is Asia’s now largest solar park, Gujarat Solar Park surpassing China’s Golmud Solar Park. With the 1.1 billion inhabitants of the nation, this park is an important step towards decreasing low carbon growth. Gujarat Solar Park is capable of generating 600 MW of solar energy. It has brought new purpose to a wasteland which spanned across 3,000 acres of land bordering Rann of Kutchi. It is estimate that the new park will produce around 66% of India’s 900 MW solar power. Furthermore, it will aid in the reduction of CO2 emissions which is currently about 8 million tons and will save 9000,000 tons of natural gas every year.
Europe today is harnessing more solar power than the rest of the world combined. This is in large part due to changes in policy to fit the development and installation of photovoltaics. These policy changes and choices are mostly in the form of subsidies and binding targets, which Europe continues to meet. An exceptional amount of photovoltaics have been installed in nations throughout the continent and prices for solar panels are continually falling.
Antarctica would seem to be prime placement for solar panels; the number of inhabitants is low and at the height of summer, there is almost a full 24 hours of sunlight. However because it is dark for 6 months out of the year this theory is easily disproven. But that doesn’t mean that efforts aren’t being made to utilize solar energy there. Much research has gone into it and there have been plans to fit renewable energy resources to Antarctica’s polarizing seasons. It’s been proposed to use wind turbines to generate energy during the half year of darkness and solar panels for the other half of sunlight. Switching off between the two could prove to be very effective if given the proper support and funding.
The development of solar energy in African has done much to bring electricity, food, and water to rural and poorer parts of Africa. Many companies have set their sights on Africa to “test the viability—and marketability—of solar-powered systems to provide electricity for lighting and other purposes in villages all over Africa.” So far the installments of solar energy have changed the lives Africans who it has been made available to. Marketability is looking up and these big energy companies may potentially move in to further develop solar energy resources on the grand scale. Such investment would improve the lives of millions in African nations.
These are just a few broad looks at efforts to increase generation of solar energy around the global. Many nations are putting more into research and development as solar power continues to change the sphere of energy production.
Clean energy subsidies provide funding and incentives for companies to make a switch to cleaner forms of energy like wind and solar. Subsidies are on three levels: federal, state, and local. A combination of subsidies from all three has the potential to cover half of the cost of a renewable energy project. This decreases money lost on such a venture for a company that is trying to gauge marketability and effectiveness in an area. But the greatest and most important of these subsidies comes in the form of tax credits, both production and investment. Such incentives are not only reserved for companies, consumers can take advantage of them as well. For consumers, subsidies may be up to half of installation costs, giving them more reason to make the switch.
References
Eaton, John. “Solar Energy Brings Food, Water, and Light to West Africa.” National Geographic. 13 Mar 2012. Web. <http://news.nationalgeographic.com/news/energy/2012/03/120314-solar-drip-irrigation-in-benin-africa/>.
Ebels, Philip. “Europe can be ‘proud’ of its solar energy policy.” EUobserver.com [Brussels] 09 Nov 2012. Web. <http://euobserver.com/solar-energy/117445>.
Espinoza, Javier. “Shedding Light on Subsidies: What incentives exist for renewables? And how exactly do hey work?” Wall Street Journal 17 Sep 2012, R6. Web. <http://online.wsj.com/article/SB10000872396390443659204577575203384685874.html >.
“Gujarat Solar Park: Asia’s largest solar power park opens.” Economic Times [Ahmedabad] 19 Apr 2012. Web. <http://articles.economictimes.indiatimes.com/2012-04-19/news/31367545_1_gujarat-solar-park-solar-project-solar-power-policy>.
Harding, Dan. “Wind and Solar Energy Power Antarctic Research Stations.” CalFinder. 20 Jul 2010. Web. <http://solar.calfinder.com/blog/solar-research/wind-solar-antarctic-stations/>.
McGroarty, Patrick. “Power to More People.” Wall Street Journal [Lomshyo] 18 Jun 2012. Web. <http://online.wsj.com/article/SB10001424052702304203604577394963618998228.html>.
Office of Indian Energy and Economic Development. Tribal Energy and Environmental Information Clearinghouse. Solar Energy Resources in the United States. Web. <http://teeic.anl.gov/er/solar/restech/dist/index.cfm>.
“Solar Energy.” New York Times 11 Oct 2012. Web. <http://topics.nytimes.com/top/news/business/energy-environment/solar-energy/index.html>.
Image:
White, Seth. POLENET. Scientists install a GPS station in the Whitmore Mountains during low temperatures and high winds.. 2012. The Antartic SunWeb. 29 Oct 2012. <http://antarcticsun.usap.gov/science/contenthandler.cfm?id=2615>.
Solar energy was the focus of our lab experiment today. Our goal was to find the relationship between light intensity and voltage and also between light’s wavelength and voltage.
We wanted to prove that greater distance results in a decrease of both light intensity and voltage.
Let me just give you some background information about solar energy and photovoltaics [read solar cells] so you have a basic knowledge of the subject before moving on to the experiment. I’ll start off with voltage and current.
CURRENT is a moving charge
VOLTAGE is the amount of energy per charge required to move charge around a circuit
The relationship between these two is seen in an electrical circuit. In a circuit, like the one pictured below, it is voltage that drives current. To better explain how this works I’ll use an analogy and hopefully this will make a bit more sense. Think of an electric circuit like a pipe system. In a pipe system, a pump pushes water through a closed pipe. This pipe is like the wire of an electric circuit and the pump is the battery. In a pipe, pressure drives water through the pipe much like an electric circuit in which voltage, generated by the battery, drives the current (electrons).
With the relationship between voltage and current explained we can move on to the big stuff. First, there’s photovoltaics which is a fancier way of saying solar cells. These cells provide a direct current of constant electricity. The amount of voltage/current of them is dependent on wavelength of light which is the length of a single cycle of the wave. Light intensity is a measure of the energy of light. Higher intensity means greater current and voltage because of the increase in the amount of generated photons.
Just these simple definitions and explanations should be enough to help develop a greater sense of what’s happening in the experiment. That’s finally out of the way so in the words of Marvin Gaye, “Let’s Get It On.”
Here’s the equipment what we used for the experiment:
• One solar cell
(pictured on right)
• One voltage probe
• One NXT adaptor
• NXT with light sensor
• One light source
• Labview VI
• Ruler
• Colored film filters (red, orange, purple, blue)
• Excel sheet
Outline of what we were to do:
Part I: Steps (measurements of voltage)
1. With no light
2. With light 0 cm away
3. Distance 1 (varied by student groups): 5 cm
4. Distance 2 (varied by student groups): 10 cm
5. Distance 3 (varied by student groups): 15 cm
Part II: Re-do with 4 colored filters – red, orange, purple, and blue (used in this order)
Part III: Graph Results – voltage vs. intensity (varies by distance); voltage for 4 different filters
Here are our results with no filters
No Light 0 cm 5 cm 10 cm 15 cm
-0.01469 0.47285 0.46002 0.42153 0.30606
-0.02752 0.54983 0.42153 0.39587 0.30606
-0.04035 0.47285 0.4087 0.47285 0.25474
-0.04035 0.51134 0.4087 0.48568 0.30606
0.06229 0.51134 0.46002 0.42153 0.24191
-0.01469 0.47285 0.4087 0.38304 0.37021
-0.02752 0.537 0.44719 0.39587 0.42153
-0.02752 0.51134 0.42153 0.48568 0.34455
-0.02752 0.46002 0.4087 0.44719 0.35738
0.01097 0.49851 0.39587 0.39587 0.44719
avg:-0.01469 avg:0.499793 avg:0.424096 avg:0.430511 avg:0.335569
The first column shows voltage with no light. You can see that results are mostly negative in number. This means that when no light is present, voltage is at its lowest because light is not as readily detected. The second column shoes results when light is 0 cm away, we held the flashlight directly against the solar cell. Here, voltage, and in turn light intensity, is greatest. This is evidence that the closer/more direct light is to the cell, the greater voltage/light intensity will be. With the following three sequences, voltage/light intensity decreases with increased distance away from the solar cell. This supports our theory that greater distance results in a decrease of both light intensity and voltage.
We used the colored filters in this order: red, orange, purple, blue. We weren’t sure what kind of results to expect. Here are our results using the colored filters:
Red Orange Purple Blue
0.4087 0.49851 0.34455 0.39587
0.39587 0.47285 0.39587 0.37021
0.49851 0.47285 0.31889 0.37021
0.51134 0.48568 0.34455 0.35738
0.47285 0.46002 0.2804 0.26757
0.48568 0.42153 0.31889 0.25474
0.4087 0.46002 0.35738 0.26757
0.39587 0.47285 0.29323 0.2804
0.46002 0.47285 0.30606 0.29323
0.39587 0.48568 0.29323 0.29323
avg:0.443341 avg:0.470284 avg:0.325305 avg:0.315041
Filters yielded voltage/light intensity from greatest to least: orange, red, purple, blue. From these results we found that the darker the color value of the filter, the darker light it let through. The solar cell detected most light from the orange and the least from the blue. This means that bright/lighter light is more easily detected when passing through lighter/brighter color values than through darker/deeper color values and that is why the voltage/light intensity was greater for orange and red than it was for purple and blue. Furthermore, filters only transmits one wavelength of color to pass through whereas no filter allows all wavelengths to pass and that is why voltage/light intensity is greater with no filter versus with a filter regardless of color.
This lab gave me a lot of insight into some things I see in my everyday life such as the differences in light that I’ve noticed in head lights versus tail lights. Now I’ll know the background behind those differences in light. Pretty cool.
In this lab we tested Faraday’s Law which states that electricity or currents and voltage are generated by changing magnetic fluxes through coiled wires. We were given a tube which was equipped with a magnet that moved back and forth through the coil of wires within the tube. The purpose of all this was to prove that more voltage would be generated with faster shaking.
This is the step-by-step process of the experiment:
1. Shake the tube at a particular rate.
2. Count the number of shakes in the data collecting interval
3. Calculate in Excel the sum of the squares of the voltages (SSVs)
We had 30 seconds to shake the generator tube as many times as we could as long as we kept track of the number of shakes. It seems easy enough however trying to shake a generator tube with the force of Goliath while trying to recite your 1-2-3s at the speed of light is p-ret-ty challenging.
Now I know this is a science class but all I could think of while shaking a generator tube that looked like this:
Was this:
My group decided to be overachievers and instead of conducting 5 tests we did 6! I know, I know [pats self on back]
The first time out the gate we shook the shake weight generator tube at the greatest rate: 83 times. The second we wanted to see what would happen [read we were being lazy] and did not shake the tube at all so: 0 times. The third: 53 times; fourth: 46 times; fifth: 34 times; sixth: 47 times.
The sum of the squares of the voltages was as follows:
First: 73.26246
Second: 99.51914
Third: 45.79768
Fourth: 64.46607
Fifth: 24.7404
Sixth: 73.25632
What should have happened is that the tests with the greatest number of shakes would have the greatest SSVs. But if I order the results according to the greatest number of shakes compared to the greatest SSVs the two don’t match. Take a look see:
Second: 0 shakes Fifth: 24.7404
Fifth: 34 shakes Third: 45.79768
Fourth: 46 shakes Fourth: 64.46607
Sixth: 47 shakes Sixth: 73.25632
Third: 53 shakes First: 73.26246
First: 83 shakes Second: 99.51914
Worse than the results not lining up is that the test with the least number of shakes has the greatest SSV. My uneducated guess is that we built up so much electricity in our first run with the 83 shakes that most of it still lingered around in the next few seconds when we didn’t shake the tube at all.
All in all, this lab was a bust and my results inconclusive. I’ll have to get back to you all on what went wrong or just how the results could be further explained. Either way I had a good time with the experiment and got a great work out in — two birds with one stone.
So check back soon for an update on this one and hopefully I’ll have some much needed answers for you guys!
