RESUMO
An accurate and fast moiré pattern analysis algorithm is proposed for a periodic metallic array placed adjacent to a patterned red-green-blue (RGB) light source with a microscopic gap utilizing Fourier transform along with the human eye contrast sensitivity function. We analyzed how the moiré pattern evolved varying tilt angles and metal array periodicities placed on the top of RGB light sources, which have their own spatial periodicities. Based on multiplicative model, moiré patterns were numerically generated and the influences of 70 tilt angles and 60 periodicities on the moiré standard deviation were thoroughly analyzed to minimize moiré visibility. Our numerical results were compared to a prior analytical approach to obtain a good agreement, and the proposed scheme can be further applied to larger scale display systems with sophisticated touch screen metal arrays.
RESUMO
In this paper we compute elastoplastic properties of hydroxyapatite single crystals from nanoindentation data using a two-step algorithm. In the first step the yield stress is obtained using hardness and Young's modulus data, followed by the computation of the flow parameters. The computational approach is first validated with data from the existing literature. It is observed that hydroxyapatite single crystals exhibit anisotropic mechanical response with a lower yield stress along the [1010] crystallographic direction compared to the [0001] direction. Both work hardening rate and work hardening exponent are found to be higher for indentation along the [0001] crystallographic direction. The stress-strain curves extracted here could be used for developing constitutive models for hydroxyapatite single crystals.
