Search results for "CERAMICS"
showing 10 items of 1599 documents
Optical properties of biocompatible polyaniline nano-composites
2006
Abstract Polyaniline (PANI) is an electro-active polymer of great interest thanks to its outstanding physical and chemical properties which make it suitable for various applications in optics, bioelectronics, biosensors, diagnostics and therapeutic devices. Unfortunately, PANI is infusible and insoluble in most common solvents and, thus, very difficult to process. In the attempt of improving processability, yet preserving its interesting properties, PANI has been synthesized in the form of particles and dispersed into a hydrogel matrix. The synthesis of PANI–hydrogel composites proceeds via γ-irradiation of PANI dispersions as obtained by ‘in situ’ polymerization of aniline in the presence …
Assessment of Arundo donax Fibers for Oil Spill Recovery Applications
2019
In the last years, natural fibers are increasingly investigated as an oil recovery system in order to overcome the oil spillage phenomena, thus preserving environment and aquatic life. In particular, lignocellulose-based fibers have recently been employed with promising results. In such a context, the aim of this paper is to assess the oil sorption capability of natural fibers extracted from the stem of the giant reed Arundo donax L., a perennial rhizomatous grass belonging to the Poaceae family that grows naturally all around the world thanks to its ability to tolerate different climatic conditions. Sorption tests in several pollutants and water as a reference were carried out. The fibers …
New methods for the determination of local residual stresses
2022
Splat solidification in thermal sprayed coatings relies on phenomena of various origins, time constants, and dimensional scales which altogether lead to complex residual stress states. As a result, in-service performance may be under or overestimated. Hence, this work aims at characterizing residual stress fields using high resolution instruments: a Raman spectrometer and a tailor-made Near-Field Scanning Microwave Microscope (NFSMM). Investigation areas are of 1 µm and 0.020 µm diameter respectively, both techniques are non-destructive and rely on electromagnetic interaction with matter.A preliminary study was conducted on sintered trigonal Cr2O3 with NFSMM as the technique is used for the…
Olleros, alfareros y fabricantes de loza en Ribesalbes, entre 1742 y 1817
2012
El desarrollo de la tradición alfarera en Ribesalbes, y el posterior establecimiento de las primeras fábricas de loza, a finales del siglo XVIII, viene determinado por los condicionantes naturales e históricos de la villa; así como por la influencia decisiva de la Real Manufactura del conde de Aranda, en la vecina población de L’Alcora. En este trabajo, a partir de diversas fuentes documentales primarias, entre las que cabe destacar los libros sacramentales del Archivo Parroquial de Ribesalbes, y la Contribución general de 1817, se constata la presencia de olleros en la Baronía, a principios del siglo XVIII. Se determinan también los nombres de algunos alfareros, registrados en los albores …
Highly efficient temperature-dependent chiral separation with a nucleotide-based coordination polymer.
2018
We report a new chiral coordination polymer, prepared from the cytidine 5′-monophosphate (CMP) nucleotide, capable of separating efficiently (enantiomeric excess of ca. 100%) racemic mixtures of L- and D-Asp in a temperature-dependent manner. The crystal structure of the host–guest adsorbate, with the D-Asp guest molecules loaded within its channels, could be solved allowing a direct visualization of the chiral recognition process.
Refined equivalent single layer formulations and finite elements for smart laminates free vibrations
2014
A family of 2D refined equivalent single layer models for multilayered and functionally graded smart magneto-electro-elastic plates is presented. They are based on variable kinematics and quasi-static behavior for the electromagnetic fields. First, the electromagnetic state of the plate is determined by solving the strong form of the electromagnetic governing equations coupled with the corresponding interface continuity conditions and external boundary conditions. The electromagnetic state is then condensed into the plate kinematics, whose governing equations can be written using the generalized principle of virtual displacements. The procedure identifies an effective elastic plate kinemati…
Variable kinematics models and finite elements for nonlinear analysis of multilayered smart plates
2015
Abstract A variable kinematics approach for moderately large deflection analysis of smart magneto-electro-elastic multilayered plates is presented. The approach is based on the condensation of the electro-magnetic state into the plate kinematics, whose nonlinear strain–displacement relationships are expressed in the von Karman sense. This leads to models resulting in an effective mechanical plate, which takes the multifield coupling effects into account by the plate stiffness, inertia and loading characteristics, consistently defined as combinations of the layers material properties. By a unified approach, both equivalent single layer and layerwise models are developed formulating the assoc…
Numerical analysis of composite plates with multiple delaminations subjected to uniaxial buckling load
2006
Abstract In this paper the buckling and post-buckling behaviour of unidirectional and cross-ply composite laminated plates with multiple delaminations has been studied. Finite elements analyses have been performed, using a linear buckling model, based on the solution of the eigenvalues problem, and a non-linear one, based on an incremental-iterative method. With non-linear method large displacements have been taken into account and also contact constraints between sublaminates have been added to avoid their interpenetration. It has been found that both delamination length and position and stacking sequence of the plies influence the critical load of the plate; furthermore, linear and non-li…
Reliability Estimation of Optimal Viscoelastic Composite Shells in Critical-Time Calculations
2003
The problem of reliability estimation for optimal viscoelastic composite shells in critical-time calculations is considered. The weight minimization of a viscoelastic composite shell, with constraints on deflections at the critical time, leads to a system deforming unstably, whose deflections grow in time with an increasing rate. A method for estimating the reliability of such shells in calculating the critical time is discussed. This time is regarded as a random variable depending on many, roughly equivalent, factors. An analysis of the reliability is carried out for different values of coefficients of variation, occurring in practice.
Frequency-dependent response and dynamic disorder
1991
Abstract This paper discusses selected aspects of the application of dynamic percolation models to ionic transport in mixed-ion superionic conductors. The discussion is based on an AB lattice gas model with hard-core repulsions and a ratio of τ, 0 ⩽ τ ⩽ ∞, between the transition rates of particles A and B. The frequency-dependent conductivity for a tracer particle is calculated within an effective-medium theory. The motion of the background B-particles is regarded as providing a fluctuating disordered environment for the tracer particles A. A crossover frequency separating high-frequency and low-frequency response is found which scales with τ as ω c ∼ τ 1 2 . The results for the dc limit ar…