Search results for "DISPLACEMENT"
showing 10 items of 433 documents
Classification of Gingival Recession
2018
Gingival recession is a common finding in many patients and is clinically manifested by an apical displacement of the gingival margin in relation to the cemento-enamel junction (CEJ). Various classification systems have been proposed to classify gingival recession defects and to predict final root coverage outcomes. Among them, the Miller classification is still the most commonly used among dental practitioners and researchers. This chapter reviews the different classification systems available for gingival recession defects and explores the strengths and limitations of them.
Dentoalveolar changes in adults promoted by the use of auxiliary expansion arch: A CBCT study
2019
Background The objective of this study was to evaluate the dentoalveolar effects and the changes of buccal cortical bone in the posterior area after expansion obtained with TMA auxiliary expansion arch in adult patients. Material and Methods A retrospective analysis of CT scans of 13 patients (6 male, 7 female) treated at a private clinic, taken immediately before and after the use of an auxiliary expansion archwire, was performed. Mean age at installation of TMA auxiliary expansion arch was 29.23 years (s.d.=9.13) and the mean age when the auxiliary arch was removed was 29.52 years (s.d.=9.16). Mean time of the use of the TMA auxiliary expansion arch was 0.29 years (s.d.=0.09). The patient…
Oxidative C-N fusion of pyridinyl-substituted porphyrins.
2018
International audience; The mild (electro) chemical oxidation of pyridin-2-ylthio-meso substituted Ni(II) porphyrins affords C-N fused cationic and dicationic pyridinium-based derivatives. These porphyrins are fully characterized and the molecular structure of one of them was confirmed by X-ray crystallography. A mechanism for the intramolecular oxidative C-N coupling is proposed based on theoretical calculations and cyclic voltammetry analyses.
A composite study on the structure and formation of ozone miniholes and minihighs over central Europe
2005
[1] Two different mechanisms have been proposed to be important for the formation of extreme total ozone events in mid-latitudes, so-called miniholes: (A) far-range meridional transport of air masses from regions with different climatological ozone mixing ratios, and (B) (local) adiabatic vertical displacement of isentropes. Here, the relative importance of these two mechanisms is studied using two different ozone profile reconstruction techniques for all miniholes and minihighs (events with anomalously high ozone) during the time period 1980–1989 over Switzerland. Composites for the two types of events of their vertical potential vorticity (PV) reveal a vertical dipole structure of PV anom…
Boundary-layer effects in wedges of piezoelectric laminates
2005
An approach to investigate boundary-layer effects in wedges of piezoelectric laminated structures is presented with the aim of ascertaining the electromechanical response characteristics. The wedge layer behavior is described in terms of generalized stress functions, which lead to a model consisting of a set of three coupled partial differential equations. The strength of the solution singularity is determined by solving the eigenvalue problem associated with the resolving system. The solution of the model is obtained by an eigenfunction expansion method coupled with a boundary collocation technique. Correspondingly, the singularity amplitude is assessed by introducing and calculating the g…
Ferroelectricity and piezoelectricity in soft biological tissue: Porcine aortic walls revisited
2017
Recently reported piezoresponse force microscopy (PFM) measurements have proposed that porcine aortic walls are ferroelectric. This finding may have great implications for understanding biophysical properties of cardiovascular diseases such as arteriosclerosis. However, the complex anatomical structure of the aortic wall with different extracellular matrices appears unlikely to be ferroelectric. The reason is that a prerequisite for ferroelectricity, which is the spontaneous switching of the polarization, is a polar crystal structure of the material. Although the PFM measurements were performed locally, the phase-voltage hysteresis loops could be reproduced at different positions on the tis…
Über das Wesen der optomotorischen Reaktionen
1953
Flying and swimming animals need to be able to avoid passive displacement by air and water currents. Optomotor reactions essentially serve this purpose. The animals must be able to distinguish precisely between sensory stimulation caused by passive displacement and by active locomotion. Stimulation due to active movements does not release optomotor reactions. Apparent exceptions to this rule, occurring only under artificial circumstances, are caused by a derangement of either normal sensory stimulation or normal movement and, consequently, of their normal correlation. Examples of both cases are discussed.
A thermotropic liquid crystal elastomer micro-actuator with integrated deformable micro-heater
2014
We present a liquid crystal elastomer (LCE) actuator with large stroke and fast reaction time. LCEs show a large macroscopic shape change when heated above the phase transition (≈120°C). Buried wafer-level fabricated micro-heaters offer optimal thermal reaction times and compact design of the actuators. A relative length change of λ = 1.28 was obtained with 320 mW power consumption. Heating the device from room temperature takes τrise = 19.7 s, cooling below the phase transition temperature from the fully contracted state needs τfall - 5.6s. We verify that the displacement may be accurately controlled by varying electrical input power.
An extrinsic interface developed in an equilibrium based finite element formulation
2019
Abstract The phenomenon of delamination in composite material is studied in the framework of hybrid equilibrium based formulation with extrinsic cohesive zone model. The hybrid equilibrium formulation is a stress based approaches defined in the class of statically admissible solutions. The formulation is based on the nine-node triangular element with quadratic stress field which implicitly satisfy the homogeneous equilibrium equations. The inter-element equilibrium condition and the boundary equilibrium condition are imposed by considering independent side displacement fields as interfacial Lagrangian variable, in a classical hybrid formulation. The hybrid equilibrium element formulation is…
Crack dynamics and crack surfaces in elastic beam lattices
1998
The dynamics of propagating cracks is analyzed in elastic two-dimensional lattices of beams. At early times, inertia effects and static stress enhancement combine so that the crack-tip velocity is found to behave as t1/7. At late times a minimal crack-tip model reproduces the numerical simulation results. With no disorder and for fast loading, a “mirror-mist-mirror” crack-surface pattern emerges. Introduction of disorder leads, however, to the formation of the “mirror-mist-hackle”–type interface typical in many experimental situations. Peer reviewed