Below is a summary of useful documents, images and links. Those been accumulated over the time and are result of the research in corresponding fields by P&A.
Quarter Wave Tube - a resonator used most commonly on air intake systems to reduce resonance. Works over a narrow frequency range, i.e. used to attenuate a specific frequency. The quarter wave tube is open at the end that connects with the air inlet pipe and closed at the other end. The frequency at which the quarter wave tube attenuates is controlled by the length of the quarter wave tube. The maximum attenuation is achieved when the cross-section of the quarter wave tube matches that of the main duct. The quarter wave tube, as per the title, a quarter of a wavelength long. The total distance that the acoustic wave travels is half a wavelength. Therefore, in the time taken for the acoustic wave to travel down the quarter wave tube and back to the main duct the acoustic wave in the main duct has moved along half a wavelength. The following link shows diagram and the operation of the quarter wave tube. Periodic Table of Elements Sorted by Thermal Conductivity Link below is for Calculators and Simulation Tools offered by University of Waterloo.
Thermal Fluid Properties Calculator
Section Properties Selected Shapes
Periodic Table of Elements Sorted by Thermal Conductivity
P&A Electronic Components Range
P&A Membrane Switch Document
Titanium Products Range
Heat Sink Performance Simulation software