The effect of image fractal properties and its interaction with visual discomfort on gait kinematics

Exposure to images of urban environments affords higher cognitive processing demands than exposure to images of nature scenes; an effect potentially related to differences in low-level image statistics such as fractals. The aim of the current study was to investigate whether the fractal dimensions of an abstract scene affect cognitive processing demands, using gait kinematics as a measure of cognitive demand. Participants (n = 40) were asked to walk towards different types of synthetic images which were parametrically varied in their fractal dimensions. At the end of each walk, participants rated each image for its visual discomfort (n = 20) or for its likability (n = 20) as potential confounding factors. Fractal dimensions were predictors of walking speed. Moreover, the interaction between fractal dimensions and subjective visual discomfort but not liking predicted velocity. Overall, these data suggest that fractal dimensions indeed contribute to environmentally induced cognitive processing demands

The effect of image fractal properties and its interaction with visual discomfort on gait kinematics

Abstract Exposure to images of urban environments affords higher cognitive processing demands than exposure to images of nature scenes; an effect potentially related to differences in low-level image statistics such as fractals. The aim of the current study was to investigate whether the fractal dimensions of an abstract scene affect cognitive processing demands, using gait kinematics as a measure of cognitive demand. Participants (n = 40) were asked to walk towards different types of synthetic images which were parametrically varied in their fractal dimensions. At the end of each walk, participants rated each image for its visual discomfort (n = 20) or for its likability (n = 20) as potential confounding factors. Fractal dimensions were predictors of walking speed. Moreover, the interaction between fractal dimensions and subjective visual discomfort but not liking predicted velocity. Overall, these data suggest that fractal dimensions indeed contribute to environmentally induced cognitive processing demands

Influence of Rare Earth Ions on the Optical Properties of Tellurite Glass

The goal of this work was to investigate the influence of rare-earth ions such as $Nd^{3+}$ and $Er^{3+}$ on the optical properties of tellurite glass of the $TeO_2-WO_3-PbO-La_2O_3$ system. The optical studies of the glasses comprised spectrophotometry (reflectance and transmittance) and spectroscopic ellipsometry. The spectrophotometric measurements yield a number of narrow absorption bands which correspond to characteristic transitions between the ground- and consecutive excited states of rare-earth ions. From ellipsometric studies, in turn, the dispersion of the refraction coefficient has been obtained which appears to be practically the same for the tellurite glass matrix and the matrix doped with $Nd^{3+}$ and $Er^{3+}$ ions

Spectroscopic Properties of Pr3+Pr^{3+} Ion in Various Tellurite Glasses

The goal of this work was to investigate the spectroscopic properties of $Pr^{3+}$ ions (of a comparable concentration of the order of 0.2 mol/dm³) embedded in the tellurite glass matrix, i.e. $TeO_2-WO_3-PbO$ modified with lanthanum and lutetium oxides. The difference is that the last components of both glasses provide ions which are optically inactive within the 4f shell, since this shell is completely empty for $La^{3+}$ ion and completely filled for $Lu^{3+}$ ion. The absorption and fluorescence spectra of $Pr^{3+}$ doped in tellurite glass has been recorded and analyzed in terms of the Judd-Ofelt theory. The studies of the glasses comprised ellipsometric, spectrophotometric and photoluminescence measurements. The ellipsometric studies yield the refraction index dispersion which appears to be quite similar for all the studied glasses. From the spectrophotometric measurements, the absorption spectra have been obtained which, for $Pr^{3+}$-doped samples, have been analyzed in terms of the Judd-Ofelt theory. Finally, the photoluminescence studies demonstrate a clear visible emission from $\text{}^3P_0$ level to lower-lying states of $Pr^{3+}$ ion

Optical and Mechanical Characterization of Zirconium Based Sol-Gel Coatings on Glass

The basic factor limiting the use of glasses is their unsatisfactory mechanical strength. The improvement of the mechanical strength of glasses is usually obtained by applying their respective thin surface layers. The object of the research was glass coated with zirconium oxide. For the application of zirconium oxide layer, dip-coating method was used. The resulting materials were subjected to detailed examination of the microstructure (SEM), and mechanical tests (Vickers hardness and modulus of elasticity). In order to evaluate the optical characteristics, the tests were performed by UV/VIS. The thickness of the overlying layers were determined using the method of ellipsometry. The study showed that the obtained sol-gel layer of zirconium oxide (IV) on glasses influence the improvement of the mechanical properties. It has been shown that the applied layers have high adhesion to the substrate

Evaluation of in vitro corrosion resistance and in vivo osseointegration properties of a FeMnSiCa alloy as potential degradable implant biomaterial

In vitro electrochemical characterization and in vivo implantation in an animal model were employed to evaluate the degradation behaviour and the biological activity of FeMnSi and FeMnSiCa alloys obtained using UltraCast (Ar atmosphere) melting. Electrochemical characterization was based on open circuit potential measurement, electrochemical impedance spectroscopy and potentiodynamic polarization techniques while the alloys were immersed in Ringer's solution at 37 °C for 7 days. Higher corrosion rates were measured for the Ca-containing material, resulting from inefficient passivation of the metal surface by oxy-hydroxide products. In vivo osseointegration was investigated on a tibia implant model in rabbits by referring to a standard control (AISI 316 L) stainless steel using standard biochemical, histological and radiological methods of investigation. Changes in the biochemical parameters were related to the main stages of the bone defect repair, whereas implantation of the alloys in rabbit's tibia provided the necessary mechanical support to the injured bone area and facilitated the growth of the newly connective tissue, as well as osteoid formation and mineralization, as revealed by either histological sections or computed tomography reconstructed images and validated by the bone morphometric indices. The present study highlighted that the FeMnSiCa alloy promotes better osteoinduction and osseconduction processes when compared to the base FeMnSi alloy or with AISI 316 L, and in vivo degradation rates correlate well with corrosion resistance measurements in Ringer's solution