# Everyday Physics: Dancing

by Sarah McPherson, AP Physics 1

When looking at a dancer, the eye sees impressive movement. Behind every performance are hours of practice, sweat, and dedication. After it’s all broken down, one can find the clockwork in dancing – physics.

A major factor in dancing is balance. Dancers have to focus on their centers of gravity when performing, for if they lean too far forward, their center of mass could go beyond the base of support, and they could fall. Balancing is even more difficult if there are partners dancing together; however, dancers can use physics to their advantage. If their centers of gravity are used correctly, the end result can be a stunning visual. For their centers of gravity to be supported, physical connection, or tension, is needed. The partners pulling on each other can help each other balance. The diagram below is a great illustration of the forces working on them.

The force of gravity is pulling them down and keeping them on the floor; likewise, the weight vectors from their centers of gravity point directly down, even though they are slightly tilted. Without the tension of their arms holding each other, both of the dancers would more than likely fall – especially the girl. Holding themselves together in this fashion creates one unit with a center of mass located somewhere between each dancer and over the base of support offered by the male dancer’s feet.

Physics also applies to swing dancing. This partner dance requires focus and momentum. For example, a very famous move in swing dancing is called “The 6 O’clock.” The female partner is directly above the male partner with her arms wrapped around his neck. The female is representative of the hour hand while her counterpart is the minute hand.

In order to reach this position, the female has to get a running start to reach the male, and then jump high enough for him to catch her. The woman’s kinetic energy during running is converted to gravitational potential energy with the assistance of the man performing work to lift the woman higher.

Though it may seem unlikely, physics is a key part of dancing. Without this science, the dancers wouldn’t be able achieve certain movements and the dance would be dull. Physics brings excitement to the dance!

Reference: http://www.hep.uiuc.edu/home/g-gollin/dance/dance_physics.html.

About the author: Sarah McPherson is a student in AP Physics 1 and is also the Drum Major for the Marching Grizzlies. In addition, she is the artist of the featured image in the page header.

# Roller Coaster Physics

Carden with his model “G Money.”

### The creation of a model:

Kendra and Leslie with their model of “No Clue.”

By kimgeddes

# Orbital Solar Energy: Powering the Entire Planet

A winning submission to the 2014 ExploraVision competition by Sarah Buelow and Henry Homiller

Solar energy is steadily increasing in popularity because it is readily available and plentiful. Individuals use solar energy to power or heat their homes, but do not generate enough electricity to make a significant impact on reducing our dependence on oil and other nonrenewable resources. If solar energy were harnessed properly, it would be possible to power the entire planet. Solar power could be harnessed more efficiently with a space-located orbital generator that allows for the removal of solar refraction and filtration that occurs in Earth’s atmosphere. Satellite systems can be designed to harness solar energy, but without proper extraction methods, the transfer of energy from space to earth is flawed, and impossible. Available technology requires the use of large and impractical rectifying antenna arrays for this task.  Our proposed design incorporates 3D meta-material lenses capable of focusing radio waves with extreme precision, thus lowering the size of the array required while increasing the transfer efficiency.

Present Technology

The proposed satellite generator takes advantage of several different existing technologies; the foremost is the photovoltaic panel. Photovoltaic or PV panels are in use already, though their fabrication makes them less practical than they could be. PV arrays are designed to capture the energy of light, particularly from the sun, and generate direct current electricity. The basic principle used is that a semiconductor, such as silicon, when bombarded by a photon, can have one of its electrons ejected, allowing it to flow from atom to atom, and generating electrical power. The semiconductor is typically doped with another element to make it P-type or N-type, based on which charge it will carry. When P-type and N-type panels are put together in an array, they acquire a built-in electric field that guides the loose electrons in one direction, generating direct current. When conductive connections are attached to the apparatus, the electrons can be pushed through an available current path by the field. Other modifications can be made, such as non-reflective coating, to maximize light absorption. The largest downside of PV arrays is that they are still expensive; however, solar power technology is one of the most rapidly growing technologies in the world (Toothman, Alduos).

The second chief technology is the receptor of the energy being transmitted to Earth. The rectifying antenna, or rectenna, has been in use for some time. A normal antenna absorbs an electromagnetic wave, typically a radio wave, and transforms its energy into electricity. The distinguishing feature of this particular antenna is that, rather than a radio antenna, which absorbs the electricity purely for information, the rectenna is attached to a rectifier which turns the AC electricity into DC, for use in charging batteries or otherwise powering mechanisms. The use of radio waves being used to send power wirelessly has been demonstrated on a small scale with relative ease, such as a remote control helicopter, and is a rapidly expanding idea (Zhang, Huang).

Third, a new study in the use of meta-materials provides a way to focus electromagnetic waves using negative refraction, allowing for much more focused applications of this form of energy. Designed by researchers at MIT, a copper-plated structured dish can be 3-D printed and used to focus radio waves, defying what traditionally would be expected from the base shape, using the complex structure of the meta-material (Chu). Lastly, the present knowledge of space and orbital mechanics is necessary in order to place the satellite and maneuver it into a geosynchronous orbit, remaining above the same place on the surface.

History of Solar Energy

Photo credit: Pannon Inipi Creations

Solar energy has been used as far back as the times of the Ancient Greeks, Chinese, and Native Americans, although their methods were very primitive. Mainly, these peoples oriented their buildings toward the sun to warm them, not fully understanding at the time how solar energy worked. These peoples also used mirrors and other reflective surfaces to light torches and fires, and, in second century B.C. Greece, used the reflective properties of bronze shields to defend the city by setting enemy ships on fire. The first known solar-powered mechanical device was a steam engine designed by French engineer Auguste Mouchout in 1866, which began the influx in solar inventions over the next fifty years. Inventors such as John Ericsson, Charles Tellier, and Frank Shuman worked on solar energy methods with irrigation, refrigeration, and locomotives. It was not until many years later, in 1954, when researchers at Bell Laboratories developed what has become the modern edge of solar energy – the photovoltaic cell, which is capable of converting light into electricity (ScienceDaily).

Of course, the photovoltaic effect was originally discovered in 1839 by French scientist Edmond Becquerel while he was experimenting with an electrolytic cell. Over the years, solar power slowly improved. Willoughby Smith discovered the photoconductivity of selenium in 1873, and three years later, William Grylls Adams and Richard Evans Day found that selenium produced electricity when exposed to light. By 1883, American inventor Charles Fritts, described the first ever solar cells made from thin strips of selenium. As time passed on, more and more people discovered or proved different methods to harness solar energy into electricity by expanding on photovoltaic devices and photoelectric effect understandings. Bell Telephone Laboratories in 1954 provided the U.S. with successful solar cells, although the efficiency of these early solar cells was a whopping four percent. Hoffman Electronics worked on improving the efficiency, going from eight percent in 1957, to nine percent in 1958, and eventually ten percent in 1959. A year later that efficiency increased by four percent bringing it up to fourteen percent. NASA also jumped on board with solar technology in 1964, with the launch of the Nimbus spacecraft – a satellite powered by a 470-watt photovoltaic ray. Efficiency and cost continued to improve, making solar cells cheaper, and more efficient as time went on. By 1977, photovoltaic manufacturing exceeded 500 kilowatts. Solar energy was added to aircraft, satellites, vehicles, and buildings, and methods for harnessing solar energy slowly improved into what it is today (U.S. Department of Energy).

Future Technology

Our proposition combines several existing ideas: the use of rectennas for wireless power, the use of solar energy production in orbit, and the study of meta-materials. By adding the technology behind the dish produced by MIT, we believe the idea for a wireless orbital solar generator is now reasonable, where it hasn’t been in the past. This opens up an entire new branch of power generation, which, with further development, could future proof the power industry with fully renewable methods of harvesting unused energy. The full task of the orbital generator is to translate energy from the sun into electricity on Earth. The first step is to capture the photons that make up the light coming from the sun by using conventional photovoltaic arrays, converting the energy into electric energy. This electrical energy would power a radio broadcaster, which would use the meta-material dish to create a focused wave that would travel through the atmosphere, reaching the rectenna array connected to the ground relay station. By keeping the orbital component in a geosynchronous orbit, the radio beam would constantly be focused on the rectenna, maximizing the efficiency of this final, most difficult step. The radio beam would then be transformed back into electric current and submitted to the power grid like any other power station.

Breakthroughs Required

The technology, while well on its way, is not quite at the level necessary to make the best use of an orbital solar generator. There are several fields that must be improved first. The study behind solar power is rapidly expanding already, and new, more efficient PV panels are being designed rapidly. Only a short time will need to pass before high efficiency, cheap, and lightweight arrays are available. In addition, the budding science of meta-materials has only just begun, and has no end of room to improve. Better designs than those that currently exist may allow even more precise focusing of radio waves, allowing for an improved efficiency in orbit-to-surface energy transfer, as well as smaller rectenna arrays. The more precise the focusing, the more energy can be successfully transferred, and the less area would be needed both on the ground for the receiving arrays, and in the air as required clear airspace. Along with a more precise electromagnetic broadcast, improvements in orbital control and telemetry will likely be in order. Faster, more accurate commands being sent to the satellite would keep it in the precise position overhead that would be required to be able to process the greatest amount of energy.

Consequences

Photo credit: green_earth_by_Skivey.jpg

The primary effect of the orbital solar generator would be, of course, generation of solar energy that would be both more efficient and more reliable. Keeping a geosynchronous orbit has the benefit of allowing greater precision and efficiency of energy transfer, but will cause the recurrence of one of the chief problems of solar panels: night time power generation would be nonexistent. However, the time period for which there would be no power would be significantly less than that of a PV array on Earth. The curvature of the Earth as well as computerized rotation and positioning of the panels would allow the satellite to absorb light for a significantly longer period each rotation. This strategy also allows for the precision in the radio wave transfer. By allotting a small area of restricted airspace, the collected energy is made much more reliable, as clouds and weather will have less detrimental effects on the production of energy. The main negative effect would be the potential interference that the radio wave beam might cause in the surrounding area. The focusing nature of the meta-material dish will lower this, but it is impossible to tell at this stage in the development of the technology to what degree the interference would remain.

The power produced over the years of operation of the satellite would make the cost of materials worthwhile, and its lifespan could be greatly increased by use of space shuttle missions for repair and possible upgrade. The new methods of energy production made available would make a step toward cutting back on fossil fuel consumption and lead in to more reliable, sustainable energy.

References

Egendorf, Laura K. Energy Alternatives. Detroit: Greenhaven, 2006. Print.

Jones, Susan. Solar Power of the Future: New Ways of Turning Sunlight into Energy. New York: Rosen Pub. Group, 2003. Print.

Toothman, Jessika, and Scott Aldous. “How Solar Cells Work.” HowStuffWorks. Discovery, n.d. Web. 11 Nov. 2013. <http://science.howstuffworks.com/environmental/energy/solar-cell.htm&gt;.

Zhang, Jingwei, and Yi Huang. Rectennas for Wireless Energy Harvesting. Rep. University of Liverpool, n.d. Web. 2 Dec. 2013.

“Solar Power.” ScienceDaily. ScienceDaily. 19 Nov. 2013 <http://www.sciencedaily.com/articles/s/solar_power.htm&gt;.

United States. Energy Efficiency and Renewable Energy. Department of Energy. The History of Solar. 2002. U.S. Department of Energy. 3 Dec. 2013 <http://www1.eere.energy.gov/solar/pdfs/solar_timeline.pdf&gt;.

Chu, Jennifer. “New Metamaterial Lens Focuses Radio Waves.” MIT’s News Office. MIT, 14 Nov. 2012. Web. 03 Dec. 2013.

# Energy Explorations with Rube Goldberg Machines

## Rube Goldberg Toaster

When challenged to design a series of energy transformations that ultimately perform a task, these students devised a clever method of making toast. They began with a diagram of their system:

And, here’s the final product. Great job guys!

By kimgeddes

# Lunar-Based Fusion with Helium-3

Photo Credit: http://i297.photobucket.com/albums/mm228/ stem50/Aristarcus_CL_01.png

by: Eric Byrd, Rachel Rogers, and Cora Olson

We have a vision for the future where the Earth could be powered for thousands of years. We believe that the next great power source will be nuclear fusion, but more specifically, nuclear fusion on the Moon. The moon has an estimated 1 million tons of a certain substance that when fused with deuterium would release enormous amounts of energy with little to no radioactive waste as a byproduct. Helium-3 exists in the surface of the Moon. Nuclear power plants on the Moon, fusing He-3 with deuterium, would not only provide almost limitless energy for Earth, but completely eliminate the danger of a nuclear melt-down. This is our vision for the future: these nuclear fusion reactors would generate power that would be sent back to Earth in microwave form and then reconverted back into electricity to be used by the nations of the world.

Present Technology
Nuclear power is nothing new to the world of science; nuclear fission, the act of splitting the nucleus of an atom and releasing energy, is currently being used as a source of energy. Although this method does not contribute to global warming like fossil fuels, this method results in large amounts of radioactive waste which cause adverse health effects if exposed outside of the reactors. With all of the nuclear reactors combined, there are about 2,000 metric tons of radioactive waste being produced each year. We know that Helium-3 would produce a safe, more reliable power source than our current methods of fission as well as other methods of fusion. In nuclear fusion of Helium-3, we would fuse Helium-3 with deuterium, giving off a proton and Helium-4 (Bennet, “Lunar Helium-3 as an Energy Source”). The product of the reaction would weigh less than the reactants, and the missing mass would be converted to energy. It does not produce any nuclear waste in the reaction. The concentration of Helium-3 in the moon’s soil is 13 ppb, which seems like a small number (“Mining the Moon.”); however, we estimate that there are over one million metric tons of Helium-3 on the moon (Bennet, “Lunar Helium-3 as an Energy Source”). One million metric tons of it would produce 20,000 terawatt years of thermal energy (Bennet, “Lunar Helium-3 as an Energy Source”). This is a very large amount of energy- a terawatt consists of one trillion watts.

As of today, fission is more commonly found than fusion. Fission splits atoms, while fusion fuses two atoms. Fission is used more often because fusion requires much more pressure and higher temperatures to happen successfully. Although fission does create energy, it also leaves behind harmful radioactive waste that is extremely harmful to the environment. Fusion also creates much more energy than its nuclear energy counterpart, fission. Because of this, the creation of fusion reactors is constantly being experimented with today as the need for energy sources becomes more urgent. Fossil fuels are being depleted and will soon be gone forever, which is why the making of a successful fusion reactor is critically important for the world. Today, there is progress underway for a commercial fusion reactor to be produced by France called “ITER” (International Thermonuclear

Experiment Reactor). It is estimated that it will produce ten times more energy than it consumes (ITER Organization). This would be the first time a commercial reactor would bring fusion to a large scale of consumers on the market, making safe nuclear fusion as a main power source for the world.

A similar reactor could be constructed on the moon, using Helium-3 instead of the lithium-based fusion being produced under the ITER project. If constructed to be used on the moon, it could effectively use fusion to create vast amounts of energy to be transmitted back to earth. When it comes to transmitting the energy back to Earth, we will use transmitting antennas and rectennas or rectifying antennas. The transmitting antennas will convert the electricity in microwaves then send it to Earth. Then, rectennas will capture microwaves and convert it back into electricity. Rectennas have been proven to work in many experiments and are very effective and have 90% efficiency (Barathwaj. and Srinag.). These antennas and the microwaves they intercept are fairly safe, too; however, transmitting antennas have not been fully proven yet.

Our Vision

We have the technology for getting to the moon, retrieving the Helium-3 and transmitting the fused energy back to Earth in microwaves. We only need to be able to produce high temperatures in a vacuum. These reactors will be on the moon along with a place to process Helium-3 and separate it from the soil. Other future technology could be fusion reactors that use solely Helium-3 in reactions. This energy would be transformed directly into electricity (“Mining the Moon.”).

Other future technology would be improved rectennas and transmitting antennas. The transmitting antennas would have a higher efficiency in converting electricity into microwaves and would also be able to reduce the amount that the beamed electricity would spread as it traveled through space. They would also be able to transmit even further distances, possibly deep into our solar system or beyond our galaxy. Rectennas would have a higher efficiency, reaching close to 100% and would take up less space on land to capture the microwaves. These rectennas will be placed across the globe so that energy could be sent anywhere at any time.

With the ITER project still underway, future research for a similar commercial reactor could be created with Helium-3. When created, this type of reactor could be used in our idea of lunar-based fusion, replacing the need for lithium and using Helium-3 once it is implemented on the moon. Although ITER is still in preliminary stages of design, it could become very useful as a revolutionary product, especially if it is manipulated for receiving energy from the moon. The reactor would not only have to be changed to be able to process Helium-3 efficiently, but it would also need to create energy transmittable through microwaves. When created, the reactor would have to be able to operate with little to no human support, which is important considering the high price of moon travel. As a commercial reactor, this product could contribute to an abundance of energy to the world.

The breakthrough in science required for this vision to be realized is being able to fuse Helium-3 and deuterium. At this moment in time, scientists are able to fuse tritium and deuterium because they fuse at low levels of energy. The energy required to fuse helium-3 and deuterium is twice the amount that we are currently able to achieve. This is a huge obstacle to overcome, but the fact that we are half-way there is promising. Another needed break through is a method for extracting large amounts of Helium-3 from the soil with a minimum output of energy. The soil must be heated to a high temperature, roughly 600 degrees Celsius, to extract the Helium-3, and though we do already have this technology, we would need a way to sustain energy on the moon so that enough of the substance can be extracted to make a practical amount of energy (Bennet, “Lunar Helium-3 as an Energy Source”). Finally, the major breakthrough required for nuclear fusion on the Moon to provide energy for Earth is the ability to convert electricity into microwaves with practical efficiency.

Conclusion

It only takes twenty-five metric tons of Helium-3 to power the United States for one year at its current energy consumption rate (Horton). If the estimate of over one million tons of Helium-3 on the moon is accurate, then it would be enough to power the U.S. for 40,000 years because only twenty-five tons is necessary to power the whole U.S. for an entire year (Bennet, “Lunar Helium-3 as an Energy Source”). Lunar-based fusion with Helium-3 will lead the US and the world to safe and sustainable power for tens of thousands of year.

Bibliography
Bennet, Gregory. “Artemis Project: Helium-3 Overview.” The Artemis Project. Artemis Society International, n.d. Web. 16 Nov. 2012. <http://www.asi.org/adb/02/09/he3-overview.html&gt;.

Bennet, Gregory. “Artemis Project: Lunar Helium-3 as an Energy Source, in a Nutshell.” Artemis Project: Lunar Helium-3 as an Energy Source, in a Nutshell. Artemis Society International, n.d. Web. 16 Nov. 2012. <http://www.asi.org/adb/02/09/he3-intro.html&gt;.

D’Souza, Marsha R., Diana M. Otalvaro, and Deep Arjun Singh. Harvesting Helium-3 from the Moon. Rep. no. IQP-NKK-HEL3-C06-C06. N.p., 17 Feb. 2006. Web. 3 Dec. 2012. <http://www.wpi.edu/Pubs/E-project/Available/E-project-031306-122626/unrestricted/IQP.pdf&gt;.

Freudenrich, Ph.D., Craig. “How Nuclear Fusion Reactors Work” 11 August 2005. HowStuffWorks.com. 16 November 2012.

G, Barathwaj., and Srinag. K. Wireless Power Transmission of Space Based Solar Power. Rep. Vol. 6. Singapore: LACSIT, 2011. IPCBEE. International Proceedings of Computer Science and Information Technology, 2011. Web. 11 Dec. 2012.

Horton, Jennifer. “Can We Harness Energy from Outer Space?” HowStuffWorks. HowStuffWorks Inc., N.d. Web. 03 Dec. 2012.
ITER Organization. “ITER – the Way to New Energy.” ITER – the Way to New Energy. ITER, n.d. Web. 11 Dec. 2012. <http://www.iter.org/proj&gt;.

“Mining The Moon.” Popular Mechanics. Hearst Communication Inc., 7 Dec. 2004. Web. 03 Dec. 2012. 11Project No. 407A, Lunar-Based Fusion with He-3

“Nuclear Fission (physics).” Encyclopedia Britannica Online. Encyclopædia Britannica Inc.,
n.d. Web. 16 Nov. 2012. <http://www.britannica.com/EBchecked/topic/421629/nuclearfission/48303/History-of-fission-research-and-technology&gt;.

“Outline History of Nuclear Energy.” History of Nuclear Energy. World Nuclear Association, June 2010. Web. 16 Nov. 2012. <http://www.world-nuclear.org/info/inf54.html&gt;.
Teitel, Amy S. “Pillaging the Moon for the Promise of Space Energy.” Diiscovery News. Discovery, 3 Sept. 2012. Web. 16 Nov. 2012. <http://news.discovery.com/space/spaceenergy-mining-the-moon-120907.html&gt;.

# Harvesting the energy from friction to create a safer bike

by Dalton Mullinax,  Jonathan Guy, Ryan Koprowski, and Matthew Laczko

Photo credit: static.environmentalgraffiti.com

Today, biker safety is often overlooked because many adults travel by car; however, young people without a driver’s license routinely rely on bicycles to travel short distances. For this reason, we wanted to find a way to increase the safety for bicyclists. Lights, being the predominant method of visibility, are absent on many bikes. For our project, we sought to improve biker safety by being able to power the lights on a bike using the friction that exists between the tires and the road. If we could harvest the energy lost due to friction, we could power the lights on the bike, thus improving biker safety.

We propose constructing bicycle tires with polyester-PDMS fiber interwoven within the fabric of the tire. The recent understanding of PDMS with polyester has opened a new door to the realm of attaining energy from frictional forces between two materials. This polyester-PDMS fabric is capable of generating energy from friction produced between the tire and the surface as the bicycle moves.

Today, many scientists around the world experiment with various methods to find ways to convert mechanical energy from two objects rubbing together to electrical energy. Physicists at the Georgia Institute of Technology in Atlanta, Georgia have found use in the triboelectric effect which is when two plastics rub together to create friction that can be harnessed by a triboelectric generator. These triboelectric generators are composed of smaller generators called nanogenerators that aid in the production of electrical energy (Toon). Although these triboelectric generators are small, the polyester piece rubs against a polydimethysiloxane (PDMS) sheet, thus creating friction that can be converted into electrical energy.

One form of this triboelectric generator is the PENG device, which is shown to the very far left in the picture below (Zyga).  This device has been proven to power the LCD screen, shown in the middle of the picture below, for upwards of one minute. Also, the PENG device has partially charged a lithium-ion battery (the image on the right in the picture) (Zyga).

The triboelectric generator uses the Piezoelectric Effect; “the piezoelectric substance is one that produces an electric charge when a mechanical stress is applied” (“Piezoelectric Effect”). The piezoelectric effect happens when a crystal acquires a charge when it is twisted, compressed, or distorted. One of the most useful characteristics of the piezoelectric effects is that is can be reversed easily (“The Piezoelectric Effect”). The figure below shows the forward and reverse motion of the piezoelectric effect.

When the piezoelectric effect material is stressed in forward motion, positive and negative particles shift which helps create an electrical field that can be harnessed through a nanogenerator. But, when the material is reversed, the electrical field does the exact opposite of the forward motion and uses an electrical field to create the piezoelectric effect material which then can be reused to make the forward motion.

Through our design, we are taking a new step toward nanotechnological use of a polyester-PDMS inner ring: we propose constructing bicycle tires with polyester-PDMS fiber interwoven within the fabric of the tire. This polyester-PDMS fabric will generate energy from friction produced between the tire and the surface as the bicycle moves.  This energy will be harvested and transmitted through a cable attached to the axle of the wheel and terminated at a connection on the handlebars of the bike. This terminal connection will then provide energy to the LED lights on the bicycle.

The picture below demonstrates the use of a PDMS with a rubber surface that can be used to create energy by touch. The inset picture shows that even the touch of a feather could set the sensor off and create energy as well as power the device through a triboelectric generator. This picture illustrates the device we will use in the rubber tires of the bicycle and demonstrates how the triboelectric generator will use friction to produce electricity to power the bicycle’s safety lights.

Photo Credit: Zhong Lin Wang, Triboelectric generator

Our idea is to put the sheets of PDMS and polyester into the interior of the bike’s tires. One sheet would rotate with the movement of the bike and the other would rub the other way with the use a counter-rotating piece also in the interior of the bike’s tires. As the bike is ridden, friction would be created between the PDMS and polyester sheets rubbing together. The triboelectric generator would capture this energy so it could power the lights on the bike. Assuming technology is developed that shows how the energy consumed into the triboelectric generator could be released, this new technology could immensely increase biker safety.

Lights added onto a bicycle will improve rider safety and also increase the safety of car drivers around the biker. More bikers will be able to travel at night because their visibility will be increased, allowing their confidence in riding at night to be greater. Plus, all the light energy produced by triboelectric generator is environmentally friendly.

References

Fan, Feng-Ru, Zhong-Qun Tian, and Zhong Lin Wang. Flexible Triboelectric Generator! Atlanta, GA: Sciverse Science Direct, 10 Jan. 2012. PDF.

Hum, Phillip W. “Exploration of Large Scale Manufacturing of Polydimethylsiloxane (PDMS) Microfluidic Devices.” Diss. Massachussets Institute of Technology, 2006. Abstract. (2006): 1-56. Print.

“The Piezoelectric Effect.” Nanomotion Piezoelectric Effect. Nanomotion, n.d. Web. 03 Dec. 2012. http://www.nanomotion.com/piezoelectric-effect.html.

“Piezoelectric Effect.” Piezoelectricity. GSU, n.d. Web. 03 Dec. 2012. http://hyperphysics.phy-astr.gsu.edu/hbase/solids/piezo.html.

Quick, Darren. “Triboelectric Generator Could Allow Electricity-generating Touchscreens.” Triboelectric Generator Could Allow Electricity-generating Touchscreens. Gizmag, 9 July 2012. Web. 27 Nov. 2012. http://www.gizmag.com/triboelectric-generator/23248/.

Sihong Wang, Long Lin, Zhong Lin Wang. Nanoscale Triboelectric- Effect-Enabled Energy Conversion for Sustainably Powering Portable Electronics. NanoLetter. Washington, DC: American Chemical Society Publications, 2012.

Toon, John. “Georgia Tech Research News.” Georgia Tech Research News RSS. N.p., 9 July 2012. Web. 27 Nov. 2012. http://gtresearchnews.gatech.edu/triboelectric-generator-produces-electricity-from-friction/.

Toon, John. “Triboelectric Generator Produces Electricity by Harnessing Frictional Forces.” GT. N.p., 10 July 2012. Web. 15 Nov. 2012. http://gatech.edu/newsroom/release.html?nid=139511.

“The TriboElectric Series.” The TriboElectric Series. N.p., 30 Nov. 2012. Web. 30 Nov. 2012. http://www.trifield.com/content/tribo-electric-series/.

Zyga, Lisa. “Pyroelectric Nanogenerator Charges Li-ion Battery with Harvested Energy.” Pyroelectric Nanogenerator Charges Li-ion Battery with Harvested Energy. N.p., 20 Nov. 2012. Web. 29 Nov. 2012. http://phys.org/news/2012-11-pyroelectric-nanogenerator-li-ion-battery-harvested.html.

# Physics merges with Biology to Keep the Heart Beating

by Julia Clark, Anna King, and Taylor Kuter

In today’s world, pacemakers are so commonplace, we hardly give them a second thought. Nearly everyone knows someone whose life depends on this device. Despite a wide variety of pacemaker models, they all have the same basic composition, and consist of the same three core parts: a battery, lead wires, and circuitry (How Pacemakers Are Made). All materials used in these parts are biocompatible, so as to be as non-harmful to the body as possible. These components all must meet a series of specifications. The circuitry of the modern pacemaker, which controls the device’s functions, contains an array of sensors, timers, and voltage regulators to control the heartbeat. All controls are generally externally programmable, allowing doctors to make non-invasive adjustments to the pacemaker’s function, if necessary. The lead wires of the device provide the physical stimulation to the heart. Leads are generally thin, insulated electrical wires with exposed ends directly attached to vital points on the heart. Many modern leads are of a “screw-in” variety, securing them to the heart in much the same way as a common screw. The wires are subjected to constant movement caused by the heart’s continuous beating, and therefore must be resistant to fracture. The battery, which powers the pacemaker, must be able to supply 5 volts of power, which is slightly more than what the heart requires for stimulation. The battery must be able to last for a minimum of four years, and must have a predictable life cycle, making it easy for the doctor to know when a replacement battery is necessary. The battery is integral to the pacemaker’s function, and must be replaced after a certain amount of time, depending on the patient. Currently, the only way of replacing the battery is through an invasive surgical procedure.

The need to undergo an operation every ten years in order to replace a pacemaker demonstrates the need for a new design of the pacemaker and how the pacemaker obtains energy. Instead of being run solely on batteries that need to be replaced, we have designed a Hematologic-Electric Pacemaker with batteries that have a back-up power supply that obtains its energy from the natural movement of blood in the patient. The purpose of our device is not to be the power source of the pacemaker but to produce enough energy from the additive that it will charge the batteries of the pacemaker. The capability of having a device that will produce the energy needed to charge the batteries of the pacemaker will eliminate the need for the replacement surgeries of pacemakers.

Our Hematologic-Electric Pacemaker will have the modern pacemaker itself and an additive that is connected by bio-compatible wire that the electrical current will run through. The additive is where the energy is created by the movement of the blood. The location in which the additive will be placed will be a vein. A section of the vein will be cut and our device added in place of the vein with skin grafts to connect the vein to the ends of the device. Stints may be needed in the vein to help support the added weight from the device. We chose the location for the device to be a vein as the pressure within the vein is low but the volume is high (Desai).

Original artwork provided by authors.

The device itself is made up of three chambers. The first inner chamber is in a shape of a barrel. Inside this barrel are propellers which are in the shape of airplane propellers. They are as if two flat surfaces lying horizontally are slightly twisted. The front propeller is made out of a harder bio-compatible material while the back propeller is made out of a more flexible material to create less turbulence in the blood as it re-enters the actual vein. As the blood from the vein travels through the barrel, the movement of the blood causes the propeller blades to spin. The shape of the propellers makes it so the blood can pass through the device freely without a large obstruction in its path. The propellers are connected to the barrel. The barrel is a magnet in which the top half of the barrel has a positive charge and the bottom half of the barrel has a negative charge. Since the propellers are connected to the barrel, the whole barrel moves as one unit. The barrel itself will be enclosed in a thin, bio-compatible membrane. Tightly wrapped around the membrane will be copper wire. To protect the body from exposed wire, the third bio-compatible casing will enclose the wire.
Our design allows the processes of electromagnetism and hematologic-electricity to occur. Electricity is “simply moving electrons” and “some metals, like copper, have electrons that are loosely held; they are easily pushed from their levels” (Intermediate Energy Infobook). The way in which our device creates electricity is similar to the turbine generators today but instead of using a substance like water to spin the turbine, the Hematologic-Electric Pacemaker uses the blood in the vein. The spinning of the barrel, or the spinning of the magnet, causes a magnetic field where the loose electrons in the copper wire, which is wrapped around the membrane of the barrel, are being pushed and pulled by the magnetic field (Intermediate Energy Infobook). The moving electrons in the wire will flow into a connected transmission line which will eventually lead to the pacemaker. There is an AC/DC converter connected to the transmission line just as the moving electrons enter into the line. Since the electrons are rapidly moving back and forth, they are moving in an alternating current. Before the electricity is able to get to the pacemaker, it needs to be transferred into a direct current. The AC/DC converter solves this issue as it converts the alternating current to a direct current so the flow of electrons is in one direction traveling toward the pacemaker.

Photo credit: Web 1/12/2012 via Creative Commons license

Once the blood is about the leave the barrel, the spinning motion of the propellers will cause the blood to leave the barrel twisting. In order to straighten out and slow down the blood flow, the membrane and the outer casing of the device is extended after the barrel. This extension of casing is called the turbulence reducing chamber. The turbulence reducing chamber solves the problem of the blood having turbulence as it leaves the device, as it allows the blood to regulate itself before it enters into the normal vein again. Inside the turbulence reducing chamber are backflow prevention valves. These valves are in place because as the blood pulses through the vein, there is an inevitable backward suction of the blood that occurs, and the backflow prevention valves make sure the blood will not re-enter into the barrel. Once the blood straightens back out inside the turbulence reducing chamber, it re-enters the actual vein.

“There are about 3 million people worldwide with pacemakers, and each year 600,000 pacemakers are implanted” (Wood, Mark A. and Kenneth A. Ellenbogen). The duration of pacemaker batteries is about 10 years, so every 10 years pacemaker patients have to undergo another surgery to replace the batteries. Our goal is to eliminate the need for replacement surgeries for the batteries of the pacemaker by our Hematologic-Electric Pacemaker.

References

Ashesh, Sheetal, Pratik, and Deeba. “History of Pacemakers.” The Physics of a Pacemaker. N.p., n.d. Web. 16 Nov. 2012.

“Benefits and Risks- Pacemakers.” Medtronic. N.p., 22 Sept. 2010. Web. 16 Nov. 2012.

“Benefits of the Advances in Cardiac Pacemaker Technology.” National Center for Biotechnology Information. U.S. National Library of Medicine. 15 Nov. 2012.

Desai, Rishi, M.D. “Arteries vs. Veins – What’s the Difference?” Blood Vessel Diseases. Khan Academy, 2012. Web. 11 Nov. 2012.

Heart Rhythm Society. “Treatment and Devices.” Treatment and Devices. Arrythmia.org, 2011. Web. 07 Dec. 2012.

Intermediate Energy Infobook. Electricity. Manassas: The NEED Project, 2012. PDF.

Laursen, Lucas. “Swiss Scientists Design a Turbine to Fit in Human Arteries.” IEEE Spectrum. IEEE Spectrum, 16 May 2011. Web. 26 Nov. 2012.

Mittal, Tarun. Pacemakers — A Journey through the Years. New Delhi: All India Institute of Medical Sciences, 10 Sept. 2005. PDF.

Rhoads, Caroline S., and John M. Miller MD. “What are some Recent Advances in Pacemaker Technology?” EMedicineHealth. 18 June 2009. Healthwise Staff. 15 Nov. 2012.

Webster, Andrew. “Scientists Create Blood Powered Turbine To Power Pacemakers.” PCMAG. Gizmodo, 17 May 2011. Web. 16 Nov. 2012.

“Who Invented the Pacemaker?” Rocket City Space Pioneers. N.p., n.d. Web. 15 Nov. 2012.

Wood, Mark A., M.D., and Kenneth A. Ellenbogen, M.D. “Cardiac Pacemakers From the Patient’s Perspective.” AHA Journals. The American Heart Association, 2012. Web. 11 Dec. 2012.

Zax, David. “A Heartbeat-Powered Pacemaker.” MIT Technology Review. 7 Nov. 2012. 16 Nov. 2012.

# “Tis the season to use physics!

This bright physics student uses his knowledge of energy transformations to light up his Christmas tree.

By kimgeddes Posted in Energy

# “Yes, Put This in My Backyard!” Generating Power with Recycled Water

by Brooke Mitchell, Chase Johnson, Chase Caldwell, and Chris Lynn

One of the major issues Americans deal with is conservation of energy and creating new and improved technology to make everyday life easier and less expensive. One method of achieving cheaper and easier energy production is the use of recycled household gray water to turn a hydroelectric turbine. Our idea for this design is to collect gray water from households and run that water through turbines that will create hydroelectricity that in turn powers the house.  Hydroelectric power has been practiced in the past, improved today, and hopefully, will be fully utilized in the future.

There are many types of technology the world uses today to generate energy. One source that I believe we need to utilize more is hydroelectricity. Currently power derived from hydroelectricity represents 24% of total electricity production in the world and 12% in the United States. Hydroelectricity works by harnessing the energy of flowing water. Water is pulled downstream, and then it meets and turns the blades of a hydroelectric turbine. The turbine shaft turns the rotor in the generator and creates electricity the same way other electrical generators do. While large hydroelectric plants that are part of a large dam structures are common, there are others hydroelectric plants that use straight river flow and do not involve dams. Other models that are micro-generators use ordinary streams to generate power.

Some of the benefits of hydroelectricity are: hydroelectricity is a clean, renewable source of energy; there is no fuel, because kinetic energy is converted into electricity by flowing water and no pollution. Hydroelectric sources currently provide roughly 1/5 of the world’s energy. Today there is not a whole lot of use for the gray water in houses, so why not put it to use?

We have designed a fantastic idea to conserve electricity in households and convert that energy into hydroelectric power. The purpose of our design is to develop hydroelectric power into a main source of electricity. By doing so, we will decrease the cost of our electric bill and will conserve large amounts of energy in the vicinity of our own household. To begin, any gray water that runs through household drains, such as water from the sink, dishwasher, washer machine, and showers, will be sent to a turbine located below the house. That turbine is then powered by the moving water that runs through the drains, and in turn, turns a generator that creates hydroelectric power. This power then flows through our house, sending electricity to our light bulbs and throughout our houses. Since the water is constantly circulating through the house and not automatically sent through a sewer system, we also have the advantage of conserving water and energy.

With power plants decreasing and hydroelectric power turbine plants increasing, our economy will develop into an efficient state which will help our economy grow out of depression. Understanding the impact of compact hydroelectric power plants beneath our households, perhaps people will take a step forward in giving a helping hand in conserving energy and making our world a healthier place to live in the future.

Sources and Photo Credits:

International Hydro Power Association. Hydro Power and the World’s Energy  Future. Ed. Canadian Hydropower Association. N.p., Nov. 2000. Web. 9 Jan. 2012. <http://www.ieahydro.org/reports/Hydrofut.pdf&gt;.

“Divided Over Dams.” The American Experience, PBS, Katya Chistik, Project Coordinator, Green Energy Ohio. Ron Feltenberger, formerly Vice President and Hydro System Designer, Universal Electric Power.

“Hydroelectric Power History.” Fuel From the Water. Bechtel BWXT, 25 Aug. 2003. Web. 9 Jan. 2012.