|Harvesting Energy From Vibrations
Vibrations from the environments we live and work in may sooon be harnessed as a clean source of electricity.
Known as 'energy harvesting', the concept has been around for over a decade, but researchers at the University of Bristol aim to make it possible to make use of a much wider range of vibrations than is currently possible.
It's hoped that within five years "energy harvesting" could be powering many more of our devices from heart monitors to mobile phones.
University of Bristol scientists are exploring how vibrations caused by machines such as helicopters and trains could be used to produce power. Vibrations from household appliances and the movement of the human body could also be harnessed in this way.
Commercial energy-harvesting devices already exist which, for instance, use vibrations from industrial pumps to power sensors monitoring the pumps' condition.
Existing devices can only exploit vibrations that have a narrow range of frequencies (the frequency is the number of vibrations occurring per second). If the vibrations don't occur at the right frequency, very little power can be produced and it will be too low to be useable. This is a big problem in applications like transport or human movement where the frequency of vibrations change all the time.
Energy harvesters generate low-level power on a similar scale to batteries but without the need for battery replacement or disposal of potentially dangerous and polluting chemicals. They are also suited to applications where hard wiring would be impracticable, vulnerable to damage or difficult to access for maintenance purposes.
"There's a huge amount of free, clean energy out there in the form of vibrations that just can't be tapped at the moment," says Dr Burrow. "Wider-frequency energy harvesters could make a valuable contribution to meeting energy needs more efficiently and sustainably."
If the research at Bristol succeeds in achieving its objectives, wider-frequency energy harvesting devices could be available for real-world use within five years..
Source: Engineering and Physical Sciences Research Council
Vibrations and Waves
by George King
Waves are the natural excitations of any medium, appearing in nearly all branches of physics and a wide range of oscillating systems.
This book offers students and general science readers a basic understanding of the physics of vibrations and waves, including simple harmonic motion, simple and damped harmonic oscillator, forced oscillations, normal modes and Fourier analysis, standing waves, traveling waves, waves in more than one dimension, and the dispersion of waves.
Based on an introductory 24-lecture course taught by the author at the University of Manchester, the text concisely describes vibrations and waves through mathematical equations with an emphasis on their physical meaning.