Fuel Cell Experiment

During our last class, I chose to conduct the Fuel Cell Experiment with the help of the group; Samantha Murray, Celine Nugul, and Assane Diop.

The objective of this experiment was to gain an understanding of the chemical processes involved with converting hydrogen and oxygen into electrical energy through building a fuel cell and allowing the process to occur.

Materials that the group provided me with included: 12 inches of platinum coated nickel wire, a popsicle stick, a 9 volt battery, a 9 volt battery clip, tape, water, and a multi-meter voltage measurer.

Prior to conducting electrical energy, the group had already constructed the fuel cell for me. They had explained that they cut the platinum coated nickel wire in half and winded them into a coiled spring and this represented the electrodes in the fuel cell. Next, they cut the leads off of the battery clip in half and stripped the insulation off of each of the ends of the wires. They then twisted the bare battery leads onto the end of the coiled wire (the electrodes). From there they attached the electrodes to the popsicle stick using tape. To complete the fuel cell, they connected the red wire to the positive terminal of the volt meter and the black to the negative terminal of the meter.

With the fuel cell constructed, I was then instructed to measure the voltage of the fuel cell without the battery being connected and then recorded my results. I then connected the battery to the wires and kept my eye on the voltage meter and recorded the reading of the meter at 15, 30, and 60 second intervals. Next, I disconnected the battery from the wires and again measured the meter at 15, 30, and 60 second intervals and noticed the change in the voltage with the battery disconnected.

My Results:

Initial reading WITHOUT battery: .002

Time (seconds) WITH battery:

15- 8.92 V

30- 8.94 V

60- 8.96 V

Time (sends) WITHOUT battery:

15- .40 V

30- 99 m/v

60- 79 m/v

When testing for voltage during this experiment, the battery must be touching the battery clip which will cause the electrodes to spilt in the water using hydrogen and oxygen which is called electrolysis. Without the battery attached to the clip, the meter should read zero but in this case, the platinum wire in the water acts as a catalyst making the process easier for the oxygen and hydrogen to combine, therefore my initial reading without the battery was close to zero at .002. The hydrogen and oxygen combine and produce energy which  I was able to conduct myself and record the increase in voltage. Since the group provided me with a 9 volt battery, the voltage was not able to exceed 9 volts and came very close to 9 volts at 8.96 volts at my final reading at the 60 second interval. When I had disconnected the electrical current, my recordings of the voltage decreased almost instantly, although the voltage does not go as low as my initial reading of .002 due to the platinum acting as a catalyst.

Pizza Box Solar Oven Lab

Group: Lauren Masaitis, Ziyu Zhan, Zhongfan Yang

  

For our final assignment this semester, we were instructed to design a laboratory exercise for other students in our class that teaches a concept of energy and sustainability that we have learned in this class. Ziyu, Zhongfan and I chose to explore the relationships between thermal energy, temperature, mass and specific heat, using a marshmallow, which has a specific heat capacity of 2.10 J/(kg°C) and a mass of 10.66 grams inside of a pizza box solar oven. We will measure the temperature inside the pizza box solar oven at set time intervals, as well as the temperature of a marshmallow at the beginning and end of the experiment.

The thermal energy of a substance is the sum of the kinetic and potential energy of its molecules. Thermal energy and temperature are related. When the temperature of an object increases, the average kinetic energy of the particles in the object increases. Because thermal energy is the total kinetic and potential energy of all the particles in an object, the thermal energy of the object increases when the average kinetic energy of its particle increases. Therefore, the thermal energy of an object increases as its temperature increases.

Heat is thermal energy that flows from something at a higher temperature to something at a lower temperature. Heat is a form of energy, so it is measured in joules (the same unit that energy is measured in).

As a substance absorbs heat, its temperature change depends on the nature of the substance, as well as the amount of heat that is added. The amount of heat that is needed to raise the temperature of 1 kg of some material by 1°C is called the specific heat of the material. Specific heat is measured in joules per kilogram degree Celsius [J/(kg°C)].

The thermal energy of an object changes when heat flows into or out of the object. If Q is the change in thermal energy and c_p is specific heat, the change in thermal energy can be calculated from the following equation: Q = (m)(c_p)(ΔT).

To begin our procedure, we needed to construct a solar oven from our pizza box. After our box was constructed, we were able to begin our experiment. We measured the temperature outside of the box and recorded it. We then set up the solar oven so that the opening of the box faces the sun and we angled the window flap so it directs sunlight into the pizza box. We then recorded the initial temperature of the marshmallow before placing it inside of the box. Once the marshmallow was inside of our box we started a timer and at five minute intervals we read and recorded the temperature of the inside of the box. Once we reached our 25 minute time interval, we opened the box immediately and recorded the temperature of the marshmallow.

Below is the data we collected and our analysis.

Analysis:

Data Collected

(In degrees Celsius)

Temperature Outside: 22°C

Initial Marshmallow Temperature: 22°C

Final Marshmallow Temperature: 29°C

Time (minutes)	Temperature (°C)
0 minutes	22°C
5 minutes	29°C
10 minutes	40°C
15 minutes	52°C
20 minutes	60°C
25 minutes	65°C

1.    Calculate the change in temperature of the marshmallow.

2.    Calculate the mass of the marshmallow.

3.    Identify the specific heat capacity of a marshmallow.

4.    Calculate the amount of thermal energy gained by the marshmallow.

·      The beginning temperature at 0 minutes was 22 °C.

·      The ending temperature at 25 minutes was 29 °C.

·      The change in temperature of the marshmallow is 7°C.

·      The specific heat capacity of a marshmallow is 2.10 J/(kg°C).

·      The Mass of a marshmallow is 10.66 grams.

Q = (m)(c_p)(ΔT)

Q = Δ(Thermal Energy)=”heat”
m = mass
c_p = specific heat capacity

T = temperature

·       Q = .01066kg2.10 J/(kg°C)7°C

Q= .156702 J

5.    Graph the change in temperature of inside the solar oven.

6.    Calculate the rate of change of the temperature of inside the solar oven.

·      Rate of Change = (y₂-y₁)/(x₂-x₁)

·      Rate of Change = (65-22)/(25-0)

·      Rate of Change = 1.72 (°C/minute)

Two things that we are able to conclude after conducting our experiment are radiation and thermal energy. Solar energy radiates from the sun to the Earth and gets trapped within our oven and this produces thermal energy within our marshmallow. When radiation strikes a material, some of the energy is absorbed, some is reflected, and some may be transmitted through the material. When a material absorbs radiant energy, the thermal energy of the material increases.

There are also a few variables to consider with our experiment.

1. We were not able to conduct this experiment outside on a warm day in the direct sunlight. If that were possible, we may have been able to get better results and a higher temperature in our oven.
2. There are ways that heat could have been lost from our solar oven:

•       The ground could have absorbed some of the heat

•       We could add more insulation to the bottom of the solar oven

•       Air was escaping out of cracks of our oven

•       We could add more tape to our box to make sure there are zero cracks

•       The amount of sunlight on the box was not consistent

•       We could add more flaps to the box to direct more sunlight into the oven

Chernobyl Accident

(This blog is replacing the Pandora’s Promise blog that I could not access the video for.)

In April 1986, a result of a flawed Soviet reactor design combined with ineffectively trained personnel responsible for operation and the lack of any safety culture, caused the Chernobyl accident in Ukraine. On the 25^th of April the personnel at Chernobyl 4 reactor started preparing for a test to determine how long turbines would spin and supply power to the main circulating pumps. This test was conducted a year prior but was unsuccessful due to the power from the turbine rapidly was depleted.

There were a series of operation steps that took place, which put the reactor in an extremely unstable condition. The planned procedure included shutting off the reactor’s emergency core cooling system that was responsible for supplying water for cooling the core in an emergency. As the process continued, the power at which the reactor was operating was less then the minimum operating reactivity margin, which is a violation. The operator made a poor decision and the process was continued. At this point, any efforts that could have been made to increase the power were disturbed by xenon poisoning, reduced coolant void, and graphite cool down.

The power excursion rate emergency protection system signals came on when power started to rise and exceeded the required level. This caused fuel elements to rupture that led to increased steam generation, which then further increased the power level. There was a rupture of several fuel channels that increased the pressure inside of the reactor that caused the reactor support plate to become detached and jammed the control rods. While the channel pipes were rupturing, more steam had been generated as a result of the lack of pressure of the reactor cooling circuit.

At this point there were two explosions. The first one was the initial steam explosion and second was a result of the build-up of hydrogen due to steam reactions. As stated by the World-Nuclear Organization, “Fuel, moderator, and structural materials were ejected, starting a number of fires, and the destroyed core was exposed to the atmosphere. One worker, whose body was never recovered, was killed in the explosions, and a second worker died in hospital a few hours later as a result of injuries received in the explosions.”

There was a massive immediate impact to the environment after the accident. At the time, this accident was named as the largest uncontrolled radioactive released into the environment for any civilian operation. For about 10 days, large amounts of radioactive substances were released into the air, which caused a social and economic disruption in Ukraine.

With the task of cleaning up the radioactivity of the site, about 200,000 people were recruited from the Soviet Union. These people received high doses of radiation, and later about 400,000 more people were called in to help and received lower does of radiation. About 116,000 residents were evacuated and later about 1,000 relocated back to the area unofficially.

Human health has been affected by the Chernobyl accident. Whether people were exposed to radiation directly fro the radioactive cloud or the radioactive materials deposited on the ground and were consumed through contaminated food there was a high level of contamination. Children’s thyroids were heavily exposed to radioactive iodine, which caused serious health concerns. 28 emergency workers died from acute radiation syndrome, 15 patients died from thyroid cancer, and it is estimated that 4,000 died from cancers caused by Chernobyl.

The main lesson learned from the Chernobyl accident is reactor safety. There have been modifications made in reactors currently operating. Following Chernobyl, the International Atomic Energy Agency brought together engineers to focus on safety improvements. According to the Chernobyl Forum report, about seven million people received or are eligible for benefits as “Chernobyl victims.”

Works Cited

"Chernobyl Nuclear Accident." Scientific Facts on  the. N.p., n.d. Web. 30 Oct. 2013. <http://www.greenfacts.org/en/chernobyl/index.htm>.

"Chernobyl fuel transfer milestone." Chernobyl. N.p., n.d. Web. 30 Oct. 2013. <http://www.world-nuclear.org/info/Safety-and-Security/Safety-of-Plants/Chernobyl-Accident/#.UnE3HRaRPFJ>.

"History of Chernobyl Disaster." ICRIN > Home >. N.p., n.d. Web. 30 Oct. 2013. <http://www.chernobyl.info/Default.aspx?tabid=274>.

MIT Nuclear Reactor Laboratory Trip

       

The MIT Nuclear Laboratory (MIT-NRL) is the second largest university research reactor in the United States and the only university research facility in the United States where students have the ability to get hands on experience with the development and implementation of nuclear engineering experimental programs. The MIT-NRL is responsible for educational training and cutting-edge research of nuclear fission engineering, material science, radiation effects in biology and medicine, neutron physics, geochemistry, and environmental studies. The NRL has been operating 24 hours a day, 7 days a week since 1958 and has been upgraded in 1975 and makes minor upgrades as needed.

During our trip to the MIT-NRL on October 18, 2013, we started by listening to a presentation made one of the directors of operations of the laboratory. During the presentation, we were briefed on the history of MIT and the reactor, the responsibilities of the employees and the reactor, and the processes that occur in the reactor.

Before we were allowed to enter the MIT-NRL we were all assigned a dosimeter that is about the size of a pen and attached them to our clothing. This meter allowed us to know how much exposure we experienced. This was intimidating due to the fact that I had the slightest idea of what I was going to walk into.

Unlike other nuclear reactors, the MIT Research Reactor does not produce electricity and is primarily responsible for the production of neutrons therefore the director of operations explained the fission process to us using a diagram (similar to the one shown below). The power level of the reactor is 6 MW, which is much smaller compared to 3000 MW for a large electric power reactor.

The NRL has contributed valuable information to many research projects during the years of operation such as closed-loop digital control of spacecraft and terrestrial reactors; boron neutron capture therapy for the treatment of cancer; material studies for the next generation of reactors; neutron activation analysis used for the study of autism; and the investigation of nanofluids for nuclear applications.

During our tour we were able to visit the medical room where the boron neutron capture therapy for the treatment of cancer took place. Our tour guide explained that doctors would use a beam to send boron into the brain to attack and destroy malicious tumors. This experiment had successful variables to it as well as unsuccessful as the doctors struggled with managing the speed of the neutrons.

An interesting piece of information that I took away from this tour was that we get more radiation in an airplane during a flight from New York City to LA than the radiation you would encounter while inside of the reactor.

My after thoughts of the MIT-NRL brought me to the Fukushima reactor, and I initially feared that this reactor could wipe out Boston similar to the disaster in Japan. Although with research, lessons learned from Fukushima have been incorporated in new safety features in nuclear reactors in several countries. The MIT-NRL has also been operating safely for over 50 years and due to the small size and low power level, it poses a much smaller threat than other reactors.

MIT Nuclear Reactor Laboratory: Home. N.p., n.d. Web. 27 Oct. 2013. <http://web.mit.edu/nrl/www/index.html>.

The Robert Stirling Invention

In 1816 Robert Stirling invented an engine that is much different than the engine in your car. The Stirling engine has the potential to be much more efficient than gasoline or diesel engines, although today it is primarily used in specialized items that focus on quiet operation such as a submarine.

What makes this engine different than the internal-combustion engines in cars is that it utilizes the Stirling cycle. During the Stirling cycle process, gasses never leave the engine, as there are no exhaust valves and results in a very quiet engine. The Stirling cycle uses an external heat source such as gasoline, solar energy, or even the heat produced by the combustion of decaying plants.

To explain how the Stirling cycle works, there is an important key principle. A fixed amount of gas is sealed inside the engine and the cycle involves changing the pressure of this gas inside the gas. A fixed amount of gas in a fixed amount of space combined with a rising temperature, pressure will increase while the opposite with cause the pressure to decrease.

Stirling engines have a sealed cylinder with one part that is hot and one that is cold. The working gas contained inside of the engine is moved from the hot side to the cold side by a mechanism. When the gas is on the hot side, it expands and pushes a piston then it moves back to the cold side and contracts. There are different types of Stirling engines and the more common types are the two-piston type Stirling engine and the displacer type Stirling engine.

The displacer type Stirling Engine is continuously heated by a heat source on the space below the displacer piston while the space above the displacer piston is continuously cooled. Below is an animation to explain this type.

The two-piston type animation is shown below demonstrating the space above the hot piston is continuously heated by a heat source while the space above the cold piston is continuously cooled.

Stirling engines are not more common because of the impracticality of use in most items. With the heat source being external, the engine encounters some delays when responding to changes in the amount of heat being applied, which caused the engine to require some time to warm up before it can produce power and the engine is not capable of changing the amount of power output quickly.

Works Cited

"American Stirling Company." American Stirling Company. N.p., n.d. Web. 27 Oct. 2013. <http://www.stirlingengine.com>.

"How Stirling Engines Work." HowStuffWorks. N.p., n.d. Web. 27 Oct. 2013. <http://auto.howstuffworks.com/stirling-engine1.htm>.

"Stirling Engine Home Page -English-." Stirling Engine Home Page -English-. N.p., n.d. Web. 27 Oct. 2013. <http://www.bekkoame.ne.jp/~khirata/indexe.htm>.

"Stirling Engine Society USA." Stirling Engine Society USA. N.p., n.d. Web. 27 Oct. 2013

            <http://www.sesusa.org>.