Examensarbeten för masterexamen // Master Theses
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Browsar Examensarbeten för masterexamen // Master Theses efter Program "Sound and vibration (MPSOV), MSc"
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- PostElectrical Characterization of Strain Effects on Bacterial Nanocellulose Treated with Carbon Nanoparticles(2012) Farjana, Sadia; Chalmers tekniska högskola / Institutionen för mikroteknologi och nanovetenskap; Chalmers University of Technology / Department of Microtechnology and NanoscienceNanocellulose, having attractive properties such as flexibility, biocompatibility, light weight, low cost and recycling possibilities, is a suitable material for sensors and actuators. Strain sensitive flexible, electrically conductive nanostructured bacterial nanocellulose (BNC) samples were obtained by modification with carbon nanoparticles. Different types of modifying agents such as double walled carbon nanotubes (DWCNT), multiwalled carbon nanotubes (MWCNT) and graphitized carbon nanoparticles (GNP) have been used to make the nanocellulose conductive. The electrical conductivity depends on the modifying agent and its dispersion process. In this project the strain effects on the mechanical and electrical properties of treated BNC samples have been investigated. To observe the strain induced electromechanical response a constant tensile force has been applied to the sample. The samples have piezoresistive properties. There is a correlation between the conductivity and the sensitivity of the samples. Keywords: strain sensor, nanocellulose, bacterial nanocellulose, carbon nanotubes, conductivity.
- PostPiezoelectric energy harvesting using stochastic resonance in rotating systems(2019) Forsberg, Gustav; Chalmers tekniska högskola / Institutionen för mikroteknologi och nanovetenskap (MC2); Lundgren, Per; Rusu, CristinaSensors can be found virtually anywhere in today’s society. With the ever developing technologies around us, the number of sensors is set to increase even faster in the near future. The Internet of Things and self-driving cars are just some of the emerging technologies that use huge amounts of sensors, and with these sensors comes the power demand of each of them. Today batteries are still the dominant power supply for sensors, however, energy harvesting technologies are in development to replace them. This thesis examines the possibility to use a piezoelectric harvester to power a sensor mounted on a flexplate in a combustion engine. By studying current technologies, a concept was established and with simulations and experiments it was evaluated. The concept combined two previous designs and eliminated components previously used, creating a smaller harvester. The final harvester was based on an off the shelf piezoelectric harvester where the proof mass and placement of the harvester was simulated in order to optimize the performance. The simulation on the final design show a peak power of 370 μW and a 3 dB bandwidth of 2.44 Hz, promising results that could be used as the foundation in the development of a functional harvester.