Abstract This study aimed to investigate the influence of processing parameters on mechanical properties auxetic polyurethane foams including Poisson’s ratio and Young’s modulus. 12 different scenarios were considered using method Plackett–Burman in design experiments with three replicates for each one. Eventually, 36 prepared densities initial thicknesses, heating temperatures times, applied c...

When adapting a product design for manufacturability and developing it into detail, the initial design intent may be distorted. Further, once attaining a fully defined product, assigned tolerances and production capacity determine the level of variation affecting each manufactured product, resulting in unit-to-unit differences in colour and geometry. Here, focus is set on visible geometrical de...

A theoretical treatment of optical tweezers is presented at a level suitable for undergraduates. We explore the Rayleigh and the geometrical optics regimes with an emphasis on the latter. We discuss a model for the geometrical optics regime, including spherical aberration effects, and show that the model can easily be implemented numerically. A comparison of the model with experimental data yie...

We discuss the relation between ‘bare’ cosmological parameters as the true spatial average characteristics that determine the cosmological model, and the parameters interpreted by observers with a “Friedmannian bias”, i.e., within a homogeneous space geometry. We may say that the latter are ‘dressed’ by the smoothed–out geometrical inhomogeneities of the surveyed spatial region. We identify two...

Research on room acoustic simulation focuses on more accurate modeling of wave effects in rooms. Today, also wave models (e.g., the boundary element method and the finite differences in time domain technique) can be used for higher frequencies, thus, in the geometrical acoustics (GA) domain. Simulations in architectural acoustics are powerful tools but their reliability depends on the input dat...

Western musicians traditionally classify pitch sequences by disregarding the effects of five musical transformations: octave shift, permutation, transposition, inversion, and cardinality change. We model this process mathematically, showing that it produces 32 equivalence relations on chords, 243 equivalence relations on chord sequences, and 32 families of geometrical quotient spaces, in which ...