Search results for "Radius of curvature"

showing 6 items of 6 documents

Calibrations and isoperimetric profiles

2007

We equip many noncompact nonsimply connected surfaces with smooth Riemannian metrics whose isoperimetric profile is smooth, a highly nongeneric property. The computation of the profile is based on a calibration argument, a rearrangement argument, the Bol-Fiala curvature dependent inequality, together with new results on the profile of surfaces of revolution and some hardware know-how.

Calibration Riemann manifold Critical points Surfaces of revolution Radius of curvature Mathematical surfaces Mathematical constants DuetsSettore MAT/03 - Geometria
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A comparative study of mechanical resistance of two reciprocating files

2019

Background To evaluate the cyclic fatigue resistance of two different Nickel-Titanium instruments, Reziflow (Komet, Brasseler GmbH & Co., Lemgo, Germany) and WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland). Material and Methods Two groups of 20 different NiTi endodontic instruments of identical tip size of 0.25 mm were tested; Reziflow and Wave-One Gold primary. Cyclic fatigue testing was performed in a stainless steel simulated root canal manufactured by reproducing the instrument’s size and taper. A simulated root canal with a 90 degrees angle of curvature and 5 mm radius of curvature was constructed for the instruments tested. The centre of the curvature was 5 mm from the tip …

Cyclic stressMaterials scienceRoot canalNiTi alloyendodontic instruments02 engineering and technologyCurvatureOperative Dentistry and EndodonticsRadius of curvature (optics)03 medical and health sciencesReciprocating motion0302 clinical medicinemedicinecyclic fatigue; endodontic instruments; heat treatment; NiTi alloy; reciprocating motion; dentistry (all)reciprocating motionGeneral DentistryOrthodonticsdentistry (all)heat treatmentResearch030206 dentistryMechanical resistancecyclic fatigue021001 nanoscience & nanotechnology:CIENCIAS MÉDICAS [UNESCO]medicine.anatomical_structureNickel titaniumUNESCO::CIENCIAS MÉDICASFracture (geology)0210 nano-technology
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Do the contact angle and line tension of surface-attached droplets depend on the radius of curvature?

2018

Results from Monte Carlo simulations of wall-attached droplets in the three-dimensional Ising lattice gas model and in a symmetric binary Lennard-Jones fluid, confined by antisymmetric walls, are analyzed, with the aim to estimate the dependence of the contact angle $(\Theta)$ on the droplet radius $(R)$ of curvature. Sphere-cap shape of the wall-attached droplets is assumed throughout. An approach, based purely on "thermodynamic" observables, e.g., chemical potential, excess density due to the droplet, etc., is used, to avoid ambiguities in the decision which particles belong (or do not belong, respectively) to the droplet. It is found that the results are compatible with a variation $[\Th…

Materials scienceStatistical Mechanics (cond-mat.stat-mech)Tension (physics)Antisymmetric relationMonte Carlo methodNucleationFOS: Physical sciences02 engineering and technologyMechanicsCondensed Matter - Soft Condensed Matter021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesRadius of curvature (optics)Contact anglePhysics::Fluid Dynamics0103 physical sciencesThermodynamic limitSoft Condensed Matter (cond-mat.soft)General Materials Science010306 general physics0210 nano-technologyCondensed Matter - Statistical MechanicsLine (formation)
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On the plateau problem for surfaces of constant mean curvature

1970

Mean curvature flowMean curvatureApplied MathematicsGeneral MathematicsGeometryCenter of curvatureRadius of curvaturePlateau's problemMathematicsCommunications on Pure and Applied Mathematics
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Failure of ProTaper rotary Ni-Ti instruments used by undergraduate students

2012

Objective: To evaluate the effect of number of uses, angle and radius of curvature and type of instrument on the fracture of ProTaper rotary instruments when used by undergraduate students. Study Design: Three hundred and seventy-six molars, with a total of 1114 root canals, extracted were instrumented by undergraduate students using ProTaper instruments according to the manufacturer´s recommendations. When fracture occurred, data were collected concerning the number of uses, type of instrument, level of fracture, angle and radius of curvature. ANOVA test were used to determine the influence of type of instrument in the incidence of instrument fracture. Logistic regression model was used to…

OrthodonticsDental materialsbusiness.industryResearchMaterials dentalsDental instruments and apparatusAnova testEstudiants universitarisOdontología:CIENCIAS MÉDICAS [UNESCO]CurvatureOdontologiaCiencias de la saludRadius of curvature (optics)Clinical and Experimental DentistryDentistryUNESCO::CIENCIAS MÉDICASFracture (geology)Aparells i instruments odontològicsMedicineCollege studentsbusinessGeneral Dentistry
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VORTEX LAYERS IN THE SMALL VISCOSITY LIMIT

2006

In this paper we suppose that the initial datum for the 2D Navier–Stokes equations are of the vortex layer type, in the sense that there is a rapid variation in the tangential component across a curve. The variation occurs through a distance which is of the same order of the square root of the viscosity. Assuming the initial as well the matching (with the outer flow) data analytic, we show that our model equations are well posed. Another necessary assumption is that the radius of curvature of the curve is much larger than the thickness of the layer.

Physicssymbols.namesakeClassical mechanicsHydrodynamic radiusStokes' lawsymbolsRadius of curvatureStokes radiusVortexWaves and Stability in Continuous Media
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