Hydrolytic and enzymatic degradation of a poly(å-caprolactone) network

“NOTICE: this is the author’s version of a work that was accepted for publication in Polymer Degradation and Stability. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Polymer Degradation and Stability, [Volume 97, Issue 8, August 2012, Pages 1241–1248] DOI 10.1016/j.polymdegradstab.2012.05.038Long-term hydrolytic and enzymatic degradation profiles of poly(å-caprolactone) (PCL) networks were obtained. The hydrolytic degradation studies were performed in water and phosphate buffer solution (PBS) for 65 weeks. In this case, the degradation rate of PCL networks was faster than previous results in the literature on linear PCL, reaching a weight loss of around 20% in 60 weeks after immersing the samples either in water or in PBS conditions. The enzymatic degradation rate in Pseudomonas Lipase for 14 weeks was also studied, with the conclusion that the degradation profile of PCL networks is lower than for linear PCL, also reaching a 20% weight loss. The weight lost, degree of swelling, and calorimetric and mechanical properties were obtained as a function of degradation time. Furthermore, the morphological changes in the samples were studied carefully through electron microscopy and crystal size through X-ray diffraction. The changes in some properties over the degradation period such as crystallinity, crystal size and Young¿s modulus were smaller in the case of enzymatic studies, highlighting differences in the degradation mechanism in the two studies, hydrolytic and enzymatic.The authors would like to acknowledge the support of the Spanish Ministry of Science and Education through the DPI2010-20399-004-03 project. JM Meseguer-Duenas and A Vidaurre also would like to acknowledge the support of the CIBER-BBN, an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. The translation of this paper was funded by the Universidad Politecnica de Valencia, SpainCastilla Cortázar, MIC.; Más Estellés, J.; Meseguer Dueñas, JM.; Escobar Ivirico, JL.; Marí Soucase, B.; Vidaurre, A. (2012). Hydrolytic and enzymatic degradation of a poly(å-caprolactone) network. Polymer Degradation and Stability. 97(8):1241-1248. https://doi.org/10.1016/j.polymdegradstab.2012.05.038S1241124897

Towards a standard typology of endogenous landslide seismic sources

The objective of this work is to propose a standard classification of seismic signals generated by gravitational processes and detected at close distances (&lt;1&thinsp;km). We review the studies where seismic instruments have been installed on unstable slopes and discuss the choice of the seismic instruments and the network geometries. Seismic observations acquired at 13 unstable slopes are analyzed in order to construct the proposed typology. The selected slopes are affected by various landslide types (slide, fall, topple and flow) triggered in various material (from unconsolidated soils to consolidated rocks). We investigate high-frequency bands (&gt;1&thinsp;Hz) where most of the seismic energy is recorded at the 1&thinsp;km sensor to source distances. Several signal properties (duration, spectral content and spectrogram shape) are used to describe the sources. We observe that similar gravitational processes generate similar signals at different slopes. Three main classes can be differentiated mainly from the length of the signals, the number of peaks and the duration of the autocorrelation. The classes are the “slopequake” class, which corresponds to sources potentially occurring within the landslide body; the “rockfall” class, which corresponds to signals generated by rock block impacts; and the “granular flow” class, which corresponds to signals generated by wet or dry debris/rock flows. Subclasses are further proposed to differentiate specific signal properties (frequency content, resonance, precursory signal). The signal properties of each class and subclass are described and several signals of the same class recorded at different slopes are presented. Their potential origins are discussed. The typology aims to serve as a standard for further comparisons of the endogenous microseismicity recorded on landslides.</p

Different landslides on mountain sides in relation with the geological and geomorphological inheritance

Bull. of Engineering Geology and Environnment, v. 62, p. 221-229 [767], 2003International audienc

Typologie et modèles de glissements de terrain : exemples de sites des Pyrénées occidentales et centrales

Plusieurs sites d’étude (Pyrénées) soumis à des glissements de terrain sont présentés avec leurs caractéristiques géologiques et géomorphologiques permettant de les classer suivant leur typologie. Pour l’ensemble des glissements de terrain, on analyse la géométrie des glissements ainsi que les facteurs géologiques et mécaniques favorisant les instabilités. Parmi les facteurs géologiques permanents on retrouve : la lithologie, la fracturation du massif, le plissement des couches, l’orientation des structures et la stratification. Sur les quatre sites étudiés, deux correspondent à des glissements de la moraine quaternaire et les deux autres à des glissements rocheux. La connaissance des différentes formes de surface de glissement, nous permet de les classer en : glissements translationnels, rotationnels ou complexes. Cette classification associée à huit modèles géométriques ainsi qu’aux différents facteurs géologiques et mécaniques permet d’expliquer les causes de la rupture et de proposer une aide à la cartographie de l’aléa « glissements de terrain » dans une perspective de gestion des risques

Typologie et modèles de glissements de terrain : exemples de sites des Pyrénées occidentales et centrales

International audiencePlusieurs sites d’étude (Pyrénées) soumis à des glissements de terrain sont présentés avec leurs caractéristiques géologiques et géomorphologiques permettant de les classer suivant leur typologie. Pour l’ensemble des glissements de terrain, on analyse la géométrie des glissements ainsi que les facteurs géologiques et mécaniques favorisant les instabilités. Parmi les facteurs géologiques permanents on retrouve : la lithologie, la fracturation du massif, le plissement des couches, l’orientation des structures et la stratification. Sur les quatre sites étudiés, deux correspondent à des glissements de la moraine quaternaire et les deux autres à des glissements rocheux. La connaissance des différentes formes de surface de glissement, nous permet de les classer en : glissements translationnels, rotationnels ou complexes. Cette classification associée à huit modèles géométriques ainsi qu’aux différents facteurs géologiques et mécaniques permet d’expliquer les causes de la rupture et de proposer une aide à la cartographie de l’aléa « glissements de terrain » dans une perspective de gestion des risques

Morphological characteristics of till formations in relation with mechanical parameters

Mathematical Geology, v. 35, n. 7, p. 835-852, 2003. http://dx.doi.org/10.1023/B:MATG.0000007782.78685.a3International audienc

Influence of Thermal Treatment on Magnetomechanical Damping of 49Fe-49Co-2V Alloy

The 2V Permendur alloy (49Fe-49Co-2V) is very useful for electrical applications requiring high magnetic flux densities. The improvement of its magnetic (maximum permeability, coercive force) and magnetomechanical (damping) properties is achieved by various thermal treatments. The results are discussed according to the influence of order, grain size, internal stresses and d.c. applied field

Méthode de localisation des moraines de convergence dans une ancienne vallée glaciaire (Pyrénées, France) : conséquence sur les instabilités des moraines et reconstruction des glaciers au Würm

Canadian Geotechnical Journal, v. 40, n. 2, p. 419-434, 2003International audienc