Veronica Engel Anna Crider Sara Kempf Cody Schwarz Piezoelectricity

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1 Veronica Engel Anna Crider Sara Kempf Cody Schwarz Piezoelectricity Piezoelectricity is a possible energy source that the world should look at as it develops more and requires more and more energy, but runs out of energy sources we have currently. Developed by people such as the Curie s, the ideas of piezoelectricity have been growing since the 1880 s. It was first really used with the ultra-somatic submarine detector, but has since grown more. Now it is used a lot more often, in many industries and even medical fields. Due to mechanical stress and crystals, energy is created that can run many things all around us. In a large scale, the price of production currently far outweighs the outcome and piezoelectricity is mainly used for smaller things, such as watches. But with further research and development, piezoelectricity may one day be used a lot more commonly. Sara Kempf Piezoelectric was first shown to be directly influencing the piezoelectric effect in 1880 by brothers, Pierre Curie and Jacques Curie. To do this they had to better understand crystal structure and how it will behave. There was a thing before this was called the pyroelectric effect, which is how certain materials generate electric potential when temperature changes. This helped show a relation between mechanical stress and electric charge. The brothers used crystals like tourmaline, quartz, topaz, cane sugar, and Rochelle salt. The two that showed the most promise for electric potential was Rochelle and quartz. These experiments the brothers did helped confirm another effect called the converse piezoelectric. It wasn t really developed more until a Woldemar Voigt published a book called Lehrbuch der Kristallphysik, which is a book on crystal physics. This book talks about 20 natural crystal classes capable of using piezoelectricity and also constants required. Before World War I piezoelectric was never used for anything practical until it was made into the device sonar. A scientist named Paul Langevin created an ultra-somatic submarine detector in In this detector there was a thin layer of quartz glued in between steel plates. There was also a hydrophone. The detector works by emitting high frequencies of sound and seeing if it can hear an echo back. This increase of using piezoelectricity in sonar then boosted its development into many different devices. An example is the phonograph. These were easy and cheap to build and maintain. Also as time progressed the ultrasonic transducer also developed so it was easy to measure viscosity and elasticity of solids and fluids. Another ultrasonic device could find flaws inside metal casts and stone objects. Once a new substance was found called Ferroelectrics. It boosted the research even more because showed the best promise for piezoelectricity and it was synthetic. Barium titanate was developed more from this and also lead to other materials being developed. One of the biggest advancements was with the bell telephone laboratories with the AT cut crystal. It was used on airplanes so they could communicate with each other. The AT cut was light weight and work with a wide range of temperatures. Since most of this development was during the war it was kept in companies. Quartz crystal was the first commercially exploited piezoelectric but they were still looking for better materials. The biggest market for this was in Japan and did not take off as much in the US. This was because japan shared their information so more optical could be overcome. In japan, a

2 scientist invented a piezoelectric igniter for making sparks in small engines. Also this lead to many cars having ultrasonic transducers, echolocation. Anna Crider Piezoelectric energy is generated from mechanical stress. When the piezoelectric sensor is under mechanical stress, its center shifts between positive and negative charges which generates an electric field. Piezoelectric sensors detect the mechanical stress in the form of pressure. The pressure sensor elements in a piezoelectric sensor are made up of a thin membrane with a large base, which then enables the applied pressure to load the elements in the piezoelectric sensors in one direction. More sophisticated piezoelectric sensors also have an acceleration element. This keeps the sensor from being triggered when exposed to even small vibrations. The acceleration element is then carefully subtracted from the signal of the pressure and the acceleration so that only the pressure is recognized. Vibration sensors have also been developed so that the energy from the vibrations is not wasted. This is done by using piezoelectric materials to turn the vibrations into electrical energy. Piezoelectric sensors are made up of piezoelectric ceramics and crystal materials. The ceramic materials have a very high sensitivity to pressure but the sensitivity lessens over time. The crystals are less sensitive, however they are more stable than the ceramic materials and do not degrade. Despite piezoelectric sensors ability to produce large amounts of energy, piezoelectric sensors are used in much of our technology that is used daily in personal life, the medical field, and in industrial settings. These sensors can be used to generate and transfer small amount of energy within devices and instruments. Piezoelectric sensors are not affected by electromagnetic fields or radiation which allows them to be used under harsh conditions. The materials used to make piezoelectric sensors are also stable at very high temperatures, up to 1000 degrees celsius. This makes them durable and a good source to transfer energy. Piezoelectric sensors are used things as complicated as medical, aerospace and nuclear instruments. They are also used in things like normal consumer electronic products that have tilt sensors and pressure sensors for touchpads, like electronic tablets and cell phones. Piezoelectric sensors are also used in the automobile industry for combustion engines. The mechanical stress that triggers the piezoelectric sensors is usually in the form of pressure. The most common form of varying pressure to trigger piezoelectric sensors is in the form of sound. Piezoelectric energy is used in electric musical instruments, such as keyboards and electric guitars, microphones, industrial testing and medical imaging. One of the most common uses for piezoelectric sensor is in the medical field. The piezoelectric sensors are used for high frequency sounds in ultrasound technology. The ultrasonic transducers in the medical equipment allow for ultrasound imaging in the medical field. The amount of energy output by piezoelectric sensors depends on how many and how big the sensors are. However, the amount of energy produced is a small amount compared to the we consume. At Rutgers University a piezoelectric energy harvesting floor was put in the Busch Campus Center. It generates about 7kWh per day which is only enough energy to power the television displays in the building. The piezoelectric sensors would have to cover a very large area to generate a large amount of energy. Despite piezoelectric energy being low compared energy consumption and the price of installing piezoelectric sensors, piezoelectric sensors are very important to our society for personal electronic devices, automobiles, industrial machines and the medical field. Cody Schwarz

3 Although piezoelectricity is a good and upcoming source of energy in today s society, there are many drawbacks that limit its potential. piezoelectricity is the appearance of an electrical potential along the sides of crystals when you squeeze it or subject it to any type of mechanical stress. Therefore, the use of this type of energy is very specific in its nature and can only be used in certain ways. For example, the use of piezoelectricity can be found in a quartz watch to help it tell the time or in voice recognition software for a computer. Now while scientists are attempting to expand the use of piezoelectricity, through things like powering a night club with the energy of people dancing, it will never be a major form of electricity because of how specific it is. With piezoelectrics only real drawback being its limited usability, it is good to look at the cost of this energy to reason whether it should or should not be used. The cost of production of piezoelectricity is extremely high. If we attempted to use piezoelectricity in a large city, like New York, to take the energy exerted by people walking around, it would take 236,000 tiles costing upwards of a hundred dollars per tile at the current time period. This would make the total net cost upwards of 23 million dollars and would save only about 46,000 dollars per year. This would mean it would take close to 500 years to make up for the cost spent. With all of these costs it probably isn t worth the cost of production. Piezoelectricity is currently not a productive means for producing energy on a large scale. The amount of money spent to install the technology, compared to the money produced by it, is too large to seriously consider it. While Piezoelectricity will never serve as a major producer of energy it could have some minor uses. For example, the tiles could directly connect to a low consumption energy device like a vending machine or a parking meter. This would help many devices to be disconnected from the grid as it does not take much energy for when a vending machine has to push out a candy bar. In the end, piezoelectricity is a cool idea, but lacks a lot of good ways to utilize the technology. Since the technology is extremely expensive it is hard to justify a good way to use it and therefore will never make be a major producer of energy. It can be used, however, as a lesson for people to teach them about energy. Knowing how piezoelectricity works and how it can be used for small things can really help us learn more about the field of energy and different ways we can try to sustain it. Veronica Engel Piezoelectricity, though small, has a large future full of possibilities. In a world so reliant on energy and quickly running out of sources, the human population needs to look at all options available, even small ones. Piezoelectricity is one of those small options that could help to run a future America. Piezoelectricity can be used in many ways and is being further developed and implemented now. It s often used in small things like electric cigarette lighters and in a similar way piezoelectricity is being used in gas burners. It s used for more than just that though. In fact, DARPA, part of the U.S. government s department of defense put a lot of research into piezoelectricity through a project called Energy Harvesting. The intention was to put piezoelectric generators into soldiers boots, the energy created could be used to power battlefield equipment. The project didn t work well due to uncomfort upon the wearer of the shoes, but research is being continued regardless. More practical uses of it could be in things such as train stations and other busy public places. Even dance floors could be converted to use piezoelectricity. If one s dance moves are literally providing light then one may dance a lot harder anyways.

4 On a larger scale, piezoelectricity could be created from the vibrations of industrial machines and used to power batteries for backup power supplies. There have been recent attempts to begin implementing piezoelectricity on a larger scale. For instance, in Tokyo and Shibuya train stations piezoelectric floors have been implemented and are currently used to power all of the ticket gates and electronic displays. In London there is a nightclub that uses piezoelectricity to generate lights, although if the place wasn t so popular it wouldn t work as well. If research and testing on piezoelectricity continues than more places like these would become popular. There would be many more nightclubs where the appeal is due to piezoelectricity, and one would be hard pressed to find a subway or train station that didn t have some sort of piezoelectricity in the floor. Piezoelectricity has been growing more and more popular from its first real use in the 1917 s. It s grown from use in a submarine detector to use in the medical and industrial field and even to common day to day usage, such as cigarette lighters and watches. Created due to mechanical stress, something created by many many people every day, it utilizes a source of energy not often thought of. Though it is expensive currently and on a large scale the outcome does not outweigh the cost, with further research and development, piezoelectricity may one day be used everywhere and be much more common than one would think.

5 Work Cited "The Piezoelectric Effect - Piezoelectric Motors & Motion Systems."Nanomotion. Nanomotion, Web. 29 Nov "The Piezoelectric Effect." Wikipedia. Wikimedia Foundation, n.d. Web. 30 Nov