Search results for "CONTACT"

Antibacterial, physical and mechanical properties of bonding agent containing synthesized Zinc Dimethacrylate

2019

Background The aim of this study includes synthesis of zinc dimethacrylate ionomer (ZDMA) by a new method, incorporate it into resin bonding and evaluate its antibacterial, physical and mechanical properties. Material and methods Resin adhesives containing 0 to 5% wt of ZDMA was produced and the following tests were accomplished: A: Antibacterial test: 1.Direct contact test. 2.Material aging; in both of them the bacterial colony counting were performed. B: Physical test: 1.Degree of conversion (D.C). 2.Evaluating the amount of released Zinc ion release in aqueous medium. C: Mechanical test: 1.Compressive strength test. 2.Shear bond test (enamel and dentine separately). The obtained results …

The interphase model applied to simulate chemically bonded anchors

2009

Propuestas creativas, educativas y terapéuticas. Cómo trabajar con alumnado con problemas sociales

2013

This article comes from the idea that Elementary Spanish classrooms are in dire need of improvement in terms of social relations, not only because of the significant cultural changes that occurred during the dawn of the twenty-first century as a result of migration flows, but because of global economic complications and technological advances that have complicated relationships. In this situation, this article offers a compilation of different activities in the area of artistic expression of Elementary Education, with the aim of improving social contact and relationships of the students of this educational stage. At the same time, it has been considered essential to characterize these activ…

La natura della responsabilità medica: il cambio di rotta

2020

ABSTRACT A tre anni di distanza dall’ approvazione della riforma il saggio propone una riflessione sulla natura della responsabilità medica ed, in particolare, sulla tenuta del presunto cambio di rotta rispetto alla teoria del contatto sociale, alla luce di un diritto vivente divenuto ius receptum e delle sollecitazioni alternative che l’autore individua in una differente lettura della nuova normativa. Three years after the approval of the reform, the essay proposes a reflection on the nature of medical liability and, in particular, on the keeping of the presumed change of course with respect to the theory of social contact, in the light of a case law that has become ius receptum and the al…

Optimal damping coefficient for a class of continuous contact models

2020

AbstractIn this study, we develop an analytical formula to approximate the damping coefficient as a function of the coefficient of restitution for a class of continuous contact models. The contact force is generated by a logical point-to-point force element consisting of a linear damper connected in parallel to a spring with Hertz force–penetration characteristic, while the exponent of deformation of the Hertz spring can vary between one and two. In this nonlinear model, it is assumed that the bodies start to separate when the contact force becomes zero. After separation, either the restitution continues or a permanent penetration is achieved. Therefore, this model is capable of addressing …

Metal/Semiconductor Barrier Properties of Non-Recessed Ti/Al/Ti and Ta/Al/Ta Ohmic Contacts on AlGaN/GaN Heterostructures

2019

This paper compares the metal/semiconductor barrier height properties of non-recessed Ti/Al/Ti and Ta/Al/Ta contacts on AlGaN/GaN heterostructures. Both contacts exhibited a rectifying behavior after deposition and after annealing at temperatures up to 550 &deg

Nonsmooth Mechanics. Convex and Nonconvex Problems

1999

Nonlinear, multivalued and possibly nonmonotone relations arise in several areas of mechanics. A multivalued or complete relation is a relation with complete vertical branches. Boundary laws of this kind connect boundary (or interface) quantities. A contact relation or a locking mechanism between boundary displacements and boundary tractions in elasticity is a representative example. Material constitutive relations with complete branches connect stress and strain tensors, or, in simplified theories, equivalent stress and strain quantities. A locking material or a perfectly plastic one is represented by such a relation. The question of nonmonotonicity is more complicated. One aspect concerns…

Anxiety and coping dispositions as predictors of the visual interaction between mother and child

1991

Abstract The “model of coping modes” distinguishes four dispositionally determined patterns of behavior (coping modes) which become apparent in stressful situations: repression, sensitization, nondefensiveness, and high anxiety. Following from this model, the present study is aimed at assessing associations between coping modes and children's looking behavior towards their mothers in a moderately stress-inducing laboratory setting. The visual exchange of 63 mothers and their eight- to 14-year-old children was observed during a ten-minute planning period for a Punch and Judy show which the child had to later perform. A close visual orientation toward the mother was registered for sensitizers…

Grafting and characterization of dodecylphosphonic acid on copper: Macro-tribological behavior and surface properties

2013

International audience; Thin film of n-dodecylphosphonic acid (DDPA) was prepared on a copper oxide substrate via a molecular self-assembly process. The composition, structure, organization, surface energy, morphology, and electrochemical behavior of the DDPA filmwere characterized bymeans of X-ray photoelectron spectroscopic analysis (XPS), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), contact angle measurement v(CAM), microscopic observations, and electrochemistry. The friction behavior of the DDPA film adsorbed on copper oxide substrate sliding against a Si3N4 ball was examined on a linear reciprocating tribological tester. Worn surfaces of the DDPA film…

“In situ” corneal and contact lens thickness changes with high resolution OCT

2012

Purpose: To show the utility of high resolution spectral domain optical coherence tomography (HR SOCT) for the in situ evaluation of epithelial, stromal and contact lens (CL) thickness changes under closed-eye conditions without lens removal. Settings: Clinical and Experimental Optometry Research Lab, University of Minho, Portugal. Methods: Eight young healthy patients wore a thick soft CL during 90 minutes under closed-eye conditions and measures of epithelial and stromal corneal thickness were obtained at regular intervals using a HR SOCT (Copernicus HR, Optopol Tech. SA, Poland). Results: Minimal changes in epithelial thickness were detected with a transient statistically significant inc…