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Number of results: 6
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Abstract

In this article, we study tilted fiber Bragg gratings (TFBGs) with tilt angles of 6◦ and 8◦, their transmission spectra, and spectral parameters that have a linear dependence on the refractive index of the environment. It is shown that there can be several such characteristics, such as the minimum, width and energy of the spectrum. The linear dependence of the spectrum width on the refractive index does not depend on the tilt angle. The linear dependence of the spectrum minimum is only observed for a tilt angle of 8◦. The results of this work can be used to create a sensor system based on an optical fiber.
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Abstract

The paper presents examinations of the surface of base concrete with a 3D scanner. Two base concrete surfaces, differently prepared, were examined, together with two measurement strategies: simple and fast 3D scanning and partial scanning in selected areas corresponding to the device measurement space. In order to complete the analysis of a concrete surface topography an original Matlab-based program TAS (Topography Analysis and Simulation) was developed for both 2D and 3D surface analyses. It enables data processing, calculation of parameters, data visualization and digital filtration.
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Abstract

This work is focused on the issue of non-measured points – one of the most important problems in surface texture measurements using optical methods. The fundamental aim of this research is to analyse errors of surface texture measurements caused by the presence of non-measured points. This study is divided into two parts. In the first part, circles with non-measured points were artificially created on peak portions of measured surfaces. In the second part – the results of measurement by a Talysurf CCI Lite interferometer were analysed. A measurement area of 3.3 × 3.3 mm contained 1024 × 1024 points. The measurements were performed with different intensity of light. Changes of parameters regarding the analysed errors depended on a surface type. The following parameters are susceptible to errors: skewness Ssk, areal material ratio Smr, as well as the following feature parameters: Spd, Sda, Sdv, Sha and Shv. Inaccuracies of measurement in valley parts of two-process textures led usually to larger errors of parameter computations compared with deviations in peak portions.
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Abstract

In high-performance optical systems, small disturbances can be sufficient to put the projected image out of focus. Little stochastic excitations, for example, are a huge problem in those extremely precise opto-mechanical systems. To avoid this problem or at least to reduce it, several possibilities are thinkable. One of these possibilities is the modification of the dynamical behavior. In this method the redistribution of masses and stiffnesses is utilized to decrease the aberrations caused by dynamical excitations. Here, a multidisciplinary optimization process is required for which the basics of coupling dynamical and optical simulation methods will be introduced. The optimization is based on a method for efficiently coupling the two types of simulations. In a concluding example, the rigid body dynamics of a lithography objective is optimized with respect to its dynamical-optical behavior.
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Abstract

The microscale deformation behaviour of the Al-4.5Cu-2Mg alloy has been studied to understand the influence of various processing routes and conditions, i.e. the gravity casting with and without grain refiner, the rheocast process and the strain induced melt activation (SIMA) process. The micromechanics based simulations have been carried out on the optical microstructures of the alloy by 2D representative volume elements (RVEs) employing two different boundary conditions. Microstructural morphology, such as the grain size, the shape and the volume fraction of α-Al and binary eutectic phases have a significant effect on the stress and strain distribution and the plastic strain localization of the alloy. It is found that the stress and strain distribution became more uniform with increasing the globularity of the α-Al grain and the α-Al phase volume fraction. The simulated RVEs also reveals that the eutectic phase carries more load, but least ductility with respect to the α-Al phase. The SIMA processed alloy contains more uniform stress distribution with less stress localization which ensures better mechanical property than the gravity cast, grain refined and rheocast alloy.
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Abstract

Present paper is a continuation of works on evaluation of red, green, blue (RGB) to hue, saturation, intensity (HSI) colour space transformation in regard to digital image processing application in optical measurements methods. HSI colour space seems to be the most suitable domain for engineering applications due to its immunity to non-uniform lightning. Previous stages referred to the analysis of various RGB to HSI colour space transformations equivalence and programming platform configuration influence on the algorithms execution. The main purpose of this step is to understand the influence of computer processor architecture on the computing time, since analysis of images requires considerable computer resources. The technical development of computer components is very fast and selection of particular processor architecture can be an advantage for fastening the image analysis and then the measurements results. In this paper the colour space transformation algorithms, their complexity and execution time are discussed. The most common algorithms were compared with the authors own one. Computing time was considered as the main criterion taking into account a technical advancement of two computer processor architectures. It was shown that proposed algorithm was characterized by shorter execution time than in reported previously results.
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