Search results for " Axis"
showing 10 items of 188 documents
Assessment of root canal enlargement using Mtwo and BioRace rotary files.
2014
Objective. To evaluate root canal enlargement following mechanical shaping using 2 nickel titanium rotary systems.Material and Methods. Forty single-rooted teeth were immersed in resin and sectioned perpendicular to the long axis at 4, 8, and 12 mm from the apex. Digital capture of sections was performed before and after canal instrumentation using Mtwo and BioRace instruments. The area increase of endodontic space was calculated by subtraction.Results. The use of both instruments has allowed the removal of great amounts of dentin from the canal walls, even when the endodontic morphology is characterized by awkwardness to reach recesses.Conclusions. Both procedures seem to be valid and no d…
An Analytical Step-by-Step Procedure to Derive the Flexural Response of RC Sections in Compression
2013
This paper proposes an analysis procedure able to determine the flexural response of rectangular symmetrically reinforced concrete sections subjected to axial load and uniaxial bending. With respect to the usual numerical approaches, based on the fibre decomposition method, this procedure is based on the use of analytical expressions of the contributions to the equilibrium given by the longitudinal reinforcement and the concrete region in compression, which depend on the neutral axis depth and the curvature at each analysis step. The formulation is developed in dimensionless terms, after a preliminary definition of the geometrical and mechanical parameters involved, so that the results are …
Highly Anisotropic Wave Propagation in All-Dielectric Active Waveguides
2018
In this communication, we integrate an active planar waveguide on a birefringent substrate to show experimental evidence of a selective propagation of the spontaneous emission into the propagating. An anisotropic response with significantly-reduced directional excitation along the optic axis as compared with its perpendicular direction is observed. We additionally provide a theoretical modal analysis of the planar microstructure, which is in good agreement with our experimental results.
Experimental study of stress-relaxation behaviour of polycarbonate after yielding
1981
The viscoelastic behaviour of a bisphenol A polycarbonate after yielding is described by means of empirical superposition of coordinates along both time and stress axis, which allow collecting stress relaxation data, taken both in tension and in compression, into a master curve.
Dynamical heterogeneities of rotational motion in room temperature ionic liquids evidenced by molecular dynamics simulations
2018
Room temperature ionic liquids (RTILs) have been shown to exhibit spatial heterogeneity or structural heterogeneity in the sense that they form hydrophobic and ionic domains. Yet studies of the relationship between this structural heterogeneity and the ∼picosecond motion of the molecular constituents remain limited. In order to obtain insight into the time scales relevant to this structural heterogeneity, we perform molecular dynamics simulations of a series of RTILs. To investigate the relationship between the structures, i.e., the presence of hydrophobic and ionic domains, and the dynamics, we gradually increase the size of the hydrophobic part of the cation from ethylammonium nitrate (EA…
<title>Effects of light polarization and crystal orientation on the holographic recording efficiency in doped LiNbO<formula><inf>&l…
2008
The holographic recording efficiency in doped LiNbO3 crystals has been studied both experimentally and theoretically depending on the type of dope, on the recording geometry and on the polarizations of the recording and readout light.. The studied crystals can be arranged in the following order by their efficiency: LiNbO3:Cu, LiNbO3:Fe (yet having a smaller thickness and donor concentration than LiNbO3:Cu), LiNbO3:Fe+Cu, LiNbO3:Fe+Ti, LiNbO3:Ti. It was found that the recording geometry with the holographic grating vector along the optical axis is much more efficient than in the perpendicular configuration.This fact is in accordance with the photorefraction theory based on photogalvanic and …
Crystal structure of Bi_{6}Sr_{8-x}Ca_{3+x}O_{22}(-0.5\leq x\leq1.7)$: a mixed valence bismuth oxide related to perovskite
1998
Abstract: The crystal structure of BiSr8-xCa3+xO22 has been determined by single-crystal X-ray diffraction. This phase is the same as Bi9Sr11Ca5Oy that was previously studied by several authors as a secondary phase in the Bi-Sr-Ca-Cu-O system and coexists in thermodynamic equilibrium with the superconductors Bi2Sr2CuO6 and Bi2Sr2CaCu2O8 It crystallizes in the monoclinic space group P2(1)/c, with cell parameters a 11.037(3) Angstrom, b = 5.971(2) Angstrom, c = 19.703(7) Angstrom, beta = 101.46(3)degrees Z = 2. The structure was solved by direct methods and full-matrix least-squares refinement. It is built up by perovskite-related blocks of composition [Sr8-xBi2Ca3+xO16] that intergrow with d…
A Standardised Approach to the Biomechanical Evaluation of Tracheal Grafts
2021
[EN] The ideal tracheal substitute must have biomechanical properties comparable to the native trachea, but currently there is no standardised approach to evaluating these properties. Here we propose a novel method for evaluating and comparing the properties of tracheal substitutes, thus systematising both measurement and data curation. This system was tested by comparing native rabbit tracheas to frozen and decellularised specimens and determining the histological characteristics of those specimens. We performed radial compression tests on the anteroposterior tracheal axis and longitudinal axial tensile tests with the specimens anastomosed to the jaw connected to a measuring system. All ca…
Self-imaging properties of a periodic microlens array: versatile array illuminator realization
1994
Abstract The general features of the wavefield diffracted by a microlens array are described. The transversal periodicity of both a refractive and a diffractive periodic microlens array allows to obtain a set of replicas of the focal intensity distribution along the optical axis of the system, with different multiplicity. The result is applied for implementing a versatile optical array illuminator, with a variable density of bright spots at the output plane. Some experimental results of the procedure are shown.
An Evanescent Field Optical Microscope
1989
We present a new form of optical microscope. An evanescent field is produced in the lower index medium of an ATR system and modulated by a sample deposited on the hypotenuse of the prism. A sharpened fiber optic probes this field and gives information about the topography of the surface.