Search results for "MATRICE"
showing 10 items of 218 documents
Conifer needles as thermoplastic composite fillers: structure and properties
2016
This study describes the properties of thermoplastic polymer composites based on polyethylene (of low and high density) and ethylene-propylene copolymers using various types of conifer needles (pine, spruce, fir, and cedar) as fillers. For the needles, thermogravimetric analysis (TGA) and TGA/Fourier transform infrared spectroscopy (TGA/FTIR) were performed to investigate their structures and thermal resistance, as required for the composite processing methods. Moreover, structural differences were studied for the analyzed fillers and composite materials (FTIR). The results were compared with the values obtained for composites with conifer wood flour. Composites with conifer needles (pine) …
Capacità portante di mensole tozze in calcestruzzo fibroso o rinforzate con FRP
2004
Laponite clay in homopolymer and tri-block copolymer matrices
2007
Macromolecule/laponite nanomaterials were studied by DSC and X-ray diffraction techniques. The matrices are poly(ethylene) glycols at various molecular masses and poly(ethylene oxides)-poly(propylene oxides)-poly(ethylene oxides) tri-block copolymers. The latter were tuned by modulating the molecular masses, at constant hydrophilic/hydrophobic ratio, and the hydrophilicity. For all the investigated systems, the enthalpy of melting (ΔH m) is nearly constant up to a given composition thereafter it increases monotonically reaching the value of the pure macromolecule. We proposed a model to interpret the DSC data. Briefly, it was invoked a mechanism of interaction following which some segments …
Photochemistry of the H2O/CO System Revisited : The HXeOH···CO Complex in a Xenon Matrix
2017
We report on the complex of a noble-gas hydride HXeOH with carbon monoxide. This species is prepared via the annealing-induced H + Xe + OH···CO reaction in a xenon matrix, the OH···CO complexes being produced by VUV photolysis of the H2O···CO complexes. The H–Xe stretching mode of the HXeOH···CO complex absorbs at 1590.3 cm–1 and it is blue-shifted by 12.7 cm–1 from the H–Xe stretching band of HXeOH monomer. The observed blue shift indicates the stabilization of the H–Xe bond upon complexation, which is characteristic of complexes of noble-gas hydrides. The HXeOH···CO species is the first complex of a noble-gas hydride with carbon monoxide and the second observed complex of HXeOH. On the ba…
Evaluación por rúbricas de la Composición Escrita en 2º ciclo de Educación Primaria
2015
Evaluación por rúbricas de la Composición Escrita en 2º ciclo de Educación Primaria. Resumen El objetivo de este estudio de tesis doctoral es elaborar y validar un sistema de rúbricas como instrumento de evaluación e información de los procesos docentes, permitiendo la medición de aprendizajes complejos; en concreto, la habilidad para componer textos escritos, cuando aún no está consolidada esta subcompetencia; es decir, durante su proceso de adquisición. El nivel educativo seleccionado para la obtención de las muestras de producción escrita es 2º Ciclo de Educación Primaria, con alumnos entre los 8 y 10 años. Y la cuestión es ¿evalúa la rúbrica construida lo que intenta medir? Para ello, s…
The nature and impacts of environmental spillovers on housing prices: A spatial hedonic analysis
2014
Abstract: This paper investigates the spatial dimension of the environmental effects. We use recent advances in spatial econometrics to show that hedonic equations produce estimates to be differently interpreted as implicit prices according to spatial models. In particularly, the i mplicit price of housing attribute combines a feedback effect and a propagation effect and may be interpreted in terms of local or global spillovers. We drive an empirical study in the estuary of the Loire, a rural and urban area well occupied by various natural areas and more artificialized ones. We study various spatial interaction patterns to test the robustness of our estimates and we find that spatial depend…
Optimization of Delayed-State Kalman-Filter-based Algorithm via Differential Evolution for Sensorless Control of Induction Motors
2010
This paper proposes the employment of the differential evolution (DE) to offline optimize the covariance matrices of a new reduced delayed-state Kalman-filter (DSKF)-based algorithm which estimates the stator-flux linkage components, in the stationary reference frame, to realize sensorless control of induction motors (IMs). The DSKF-based algorithm uses the derivatives of the stator-flux components as mathematical model and the stator-voltage equations as observation model so that only a vector of four variables has to be offline optimized. Numerical results, carried out using a low-speed training test, show that the proposed DE-based approach is very promising and clearly outperforms a cla…
A fast hierarchical BEM for 3-D anisotropic elastodynamics
2011
Influence of flavour transfer between different gel phases on perceived aroma
2007
International audience; Multiphasic models of stirred fruit yoghurts made from a bilayer that consisted of a pectin and a dairy gel were developed in order to study the transfer of strawberry flavour compounds between the two phases. Several parameters (i.e., the flavour concentration, the fat content of the dairy gel and the storage temperature) affecting flavour compound transfer, using an experimental design, together with their effect on sensory perception were investigated. Strawberry flavour transfer between the two gels was high enough to affect the sensory perception of the dairy gels. The parameters that modified the partitioning of ethyl esters between the pectin and dairy gel (i.…