Search results for "Exponent"

Dynamical behaviour of pneumatic artificial muscles

2014

The mechanical response of pneumatic artificial muscles is analyzed in transient and periodic conditions, assuming the inextensibility of the sheathing fibres and considering the influence of the texture geometry, of the dissipation due to the mutual sliding between the braids and of the stress field inside the bladder thickness, where the constituent elastomer is regarded as a two-parameter Mooney–Rivlin material. The polytropic exponent of the thermodynamic air evolution inside the muscle during the charging and discharging phases may be properly chosen depending on the working frequency. The muscle end shape is taken into account profiling the meridian section by a simple m-degree parabo…

Publisher’s Note: Strain hardening in liquid-particle suspensions [Phys. Rev. E72, 061402 (2005)]

2006

The effect of interface roughness on exchange bias in La0.7Sr0.3MnO3 - BiFeO3 heterostructures

2016

We characterized the interfaces of heterostructures with different stack sequences of La0.7Sr0.3MnO3/BiFeO3 (LSMO/BFO) and BFO/LSMO using TEM revealing sharp and rough interfaces, respectively. Magnetometry and magnetoresistance measurements do not show a detectable exchange bias coupling for the multistack with sharp interface. Instead, the heterostructures with rough and chemically intermixed interfaces exhibit a sizable exchange bias coupling. Furthermore, we find a temperature-dependent irreversible magnetization behavior and an exponential decay of coercive and exchange bias field with temperature suggesting a possible spin-glass-like state at the interface of both stacks.

Positron lifetime measurements on neutron‐irradiated InP crystals

1996

Neutron‐irradiated InP single crystals have been investigated by positron‐lifetime measurements. The samples were irradiated with thermal neutrons at different fluences yielding concentrations for Sn‐transmuted atoms between 2×1015 and 2×1018 cm−3. The lifetime spectra have been analyzed into one exponential decay component. The mean lifetimes show a monotonous increase with the irradiation dose from 246 to 282 ps. The increase in the lifetime has been associated to a defect containing an Indium vacancy. Thermal annealing at 550 °C reduces the lifetime until values closed to those obtained for the as‐grown and conventionally doped InP crystals. navarrof@evalvx.ific.uv.es ; Jose.Ferrero@uv.es

Comparative evaluation of orthodontic bracket base shapes on shear bond strength and adhesive remnant index : an in vitro study

2017

BACKGROUND The objective of this study was to evaluate the effect of orthodontic bracket base shape on shear bond strength and adhesive remnant index. MATERIAL AND METHODS In this in vitro study using 140 bovine incisors, shear bond strength (SBS) of brackets with different base shapes (rectangle, flower, round, heart, diamond, star, and football) were measured with an Instron testing machine and tested until bond failure. Adhesive Remnant Index (ARI) scoring was evaluated after debonding to evaluate the location of bond failure. Descriptive and one-way ANOVA post-hoc Tukey statistical analyses were performed with a statistical significance set at p≤0.05. RESULTS Statistically significant d…

Strength distribution in paper

1998

Abstract Tensile strength distributions are studied in four paper samples that exhibit a variety of brittle-to-ductile properties. 1005 tensile specimens were measured in each case. The standard Gumbel and Weibull distributions, and a recently proposed double exponential modification of the former are compared with the observations visually and using chi-squared and Kolmogorov–Smirnov tests. The Gumbel distribution fails to fit the data while the Weibull distribution gives satisfactory agreement. However, the double exponential distribution fits the data best, regardless of the ductility of the material.

Experimental validation of a fractional model for creep/recovery testing of asphalt mixtures

2012

Abstract Prediction of asphalt mixtures’ behavior during their service life is a challenge due to its complexity and sensitivity to environmental and loading conditions. It has been proved that, when subjected to loading conditions comparable with most pavement operating conditions, asphalt mixtures behave as linear visco-elastic (LVE) materials. Traditionally the LVE behavior of bituminous material is modeled via creep/recovery functions. In the past, several rheological models constituted by elastic and viscous elements arranged in series or in parallel (analogical models) have been proposed and specified for both bitumen and asphalt mixtures. The corresponding constitutive laws always in…

Explicit polynomial solutions of fourth order linear elliptic Partial Differential Equations for boundary based smooth surface generation

2011

We present an explicit polynomial solution method for surface generation. In this case the surface in question is characterized by some boundary configuration whereby the resulting surface conforms to a fourth order linear elliptic Partial Differential Equation, the Euler–Lagrange equation of a quadratic functional defined by a norm. In particular, the paper deals with surfaces generated as explicit Bézier polynomial solutions for the chosen Partial Differential Equation. To present the explicit solution methodologies adopted here we divide the Partial Differential Equations into two groups namely the orthogonal and the non-orthogonal cases. In order to demonstrate our methodology we discus…

Numerical study of blow-up and dispersive shocks in solutions to generalized Korteweg–de Vries equations

2015

Abstract We present a detailed numerical study of solutions to general Korteweg–de Vries equations with critical and supercritical nonlinearity, both in the context of dispersive shocks and blow-up. We study the stability of solitons and show that they are unstable against being radiated away and blow-up. In the L 2 critical case, the blow-up mechanism by Martel, Merle and Raphael can be numerically identified. In the limit of small dispersion, it is shown that a dispersive shock always appears before an eventual blow-up. In the latter case, always the first soliton to appear will blow up. It is shown that the same type of blow-up as for the perturbations of the soliton can be observed whic…

MUTUAL INDUCTANCE FOR AN EXPLICITLY FINITE NUMBER OF TURNS

2011

Non coaxial mutual inductance calculations, based on a Bessel function formulation, are presented for coils modelled by an explicitly flnite number of circular turns. The mutual inductance of two such turns can be expressed as an integral of a product of three Bessel functions and an exponential factor, and it is shown that the exponential factors can be analytically summed as a simple geometric progression, or other related sums. This allows the mutual inductance of two thin solenoids to be expressed as an integral of a single analytical expression. Sample numerical results are given for some representative cases and the approach to the limit where the turns are considered to be smeared ou…