Recent Submissions
Publication
Seed dormancy and longevity in Stipa tenacissima L. (Poaceae)
(Springer-Verlag, 2003-09) Gasque Albalate, Maria Concepcion; Garcia-Fayos, Patricio; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Dpto. de Física Aplicada; Generalitat Valenciana; Consejo Superior de Investigaciones Científicas
[EN] In the present paper we studied the life history traits related to seed germination of Stipa tenacissima, a key species in semiarid environments of western Mediterranean areas. S. tenacissima is a perennial tussock grass, which has traditionally been considered to expand mainly by vegetative propagation with little or no sexual reproduction. We analysed seed longevity as well as the type of seed dormancy and the role of the seed covers from seeds collected from different populations in SE Spain. We also studied the variation in seed germinability among populations, individuals, and years and the ability of seeds of S. tenacissima to form soil seed banks. There was significant variation in seed germination among individuals, populations and years. Lemma and palea were the main factor controlling these differences since their removal promoted higher and faster germination and eliminated the differences in germination parameters among populations. However, the control of dormancy by lemma and palea was independent of their weight, suggesting that their chemical nature plays a more important role than does size in controlling seed germination. Mechanical scarification treatments ( via abrasion with sand) did not affect seed germination. The decay in seed germinability two years after seed collection and the low density of viable seeds in soils one year after seed dispersal indicated that S. tenacissima forms transient soil seed banks.
Publication
Radiometric Cross-Calibration of the Chilean Satellite FASat-C Using RapidEye and EO-1 Hyperion Data and a Simultaneous Nadir Overpass Approach
(MDPI AG, 2016-07) Barrientos, Carolina; Mattar, Cristian; Nakos, Theodoros; Perez, Waldo
The absolute radiometric calibration of a satellite sensor is the critical factor that ensures the usefulness of the acquired data for quantitative applications on remote sensing. This work presents the results of the first cross-calibration of the sensor on board the Sistema Satelital de Observación de la Tierra (SSOT) Chilean satellite or Air Force Satellite FASat-C. RapidEye-MSI was chosen as the reference sensor, and a simultaneous Nadir Overpass Approach (SNO) was applied. The biases caused by differences in the spectral responses of both instruments were compensated through an adjustment factor derived from EO-1 Hyperion data. Through this method, the variations affecting the radiometric response of New AstroSat Optical Modular Instrument (NAOMI-1), have been corrected based on collections over the Frenchman Flat calibration site. The results of a preliminary evaluation of the pre-flight and updated coefficients have shown a significant improvement in the accuracy of at-sensor radiances and TOA reflectances: an average agreement of 2.63% (RMSE) was achieved for the multispectral bands of both instruments. This research will provide a basis for the continuity of calibration and validation tasks of future Chilean space missions.
Publication
Influence of the t33-stress on the 3-D stress state around corner cracks in an elastic plate
(PERGAMON-ELSEVIER SCIENCE LTD, 2011-01) González-Albuixech, V.F.; Giner Maravilla, Eugenio; Fernández-Sáez, J.; Fernández-Canteli, A.; Dpto. de Ingeniería Mecánica y de Materiales; Escuela Técnica Superior de Ingeniería del Diseño; Instituto Universitario de Investigación Concertado de Ingeniería Mecánica y Biomecánica; Gobierno del Principado de Asturias; Ministerio de Ciencia e Innovación
[EN] When an analysis of the 3-D crack behavior in LEFM is performed, usually only the first term of the Williams series expansion, which corresponds to the r-12 singularity, is taken into account. However, it is well known that t ij stresses (second order terms) have still influence. Even when the t ij stresses are introduced, the only term usually taken into account corresponds to the t 11 factor, generally called T-stress. If a correct 3-D description has to be done, the t 33 term has also to be considered. In this work, the relevance of the t 33 stress term in the analysis of a mode I corner crack is shown in contrast to other approaches that use certain ad hoc parameters, such as the so called T z-constraint factor proposed by Guo and co-workers. The analysis is carried out for elliptical corner cracks with different aspect ratios, showing that the introduction of the t 33 description avoids the approximations inherent to the T z approach. © 2010 Elsevier Ltd.
Publication
Enhanced Interfacial Adhesion of Polylactide/Poly(e-caprolactone)/Walnut Shell Flour Composites by Reactive Extrusion with Maleinized Linseed Oil
(MDPI AG, 2019-05) Montava Jordà, Sergi; Quiles Carrillo, Luis Jesús; Richart, Nuria; Torres Giner, Sergio; Montañés Muñoz, Néstor; Instituto de Diseño para la Fabricación y Producción Automatizada; Dpto. de Ingeniería Mecánica y de Materiales; Instituto de Tecnología de Materiales; Escuela Politécnica Superior de Alcoy; Instituto Universitario de Ingeniería de Alimentos (FoodUPV); Agencia Estatal de Investigación; Ministerio de Economía y Competitividad; Ministerio de Educación, Cultura y Deporte
[EN] Novel green composites were prepared by melt compounding a binary blend of polylactide (PLA) and poly("-caprolactone) (PCL) at 4/1 (wt/wt) with particles of walnut shell flour (WSF) in the 10¿40 wt % range, which were obtained as a waste from the agro-food industry. Maleinized linseed oil (MLO) was added at 5 parts per hundred resin (phr) of composite to counteract the intrinsically low compatibility between the biopolymer blend matrix and the lignocellulosic fillers. Although the incorporation of WSF tended to reduce the mechanical strength and thermal stability of PLA/PCL, the MLO-containing composites filled with up to 20 wt % WSF showed superior ductility and a more balanced thermomechanical response. The morphological analysis revealed that the performance improvement attained was related to a plasticization phenomenon of the biopolymer blend and, more interestingly, to an enhancement of the interfacial adhesion of the green composites achieved by extrusion with the multi-functionalized vegetable oil.
Publication
Can Industry Counteract the Ecological Crisis? An Approach for the Development of a New Circular Bioeconomic Model Based on Biocomposite Materials
(MDPI AG, 2023-02-28) Fernández Fortunato, Eugenia Eliana; Jiménez Saez, Fernando; Hontoria Hernández, Eloy; Instituto de Gestión de la Innovación y del Conocimiento; Dpto. de Proyectos de Ingeniería; Escuela Técnica Superior de Ingeniería Industrial
[EN] The ecological crisis we are facing, in addition to depleting non-renewable raw materials, has driven the emergence of biocomposite (BC) materials as a sustainable alternative that can create new opportunities for industrial product design and development. The use of biological resources in economic processes, as the bioeconomy (BE) model proposes, can lead to a transformation from the traditional linear extractive production logic to a new productive paradigm. This paper analyses technical and scientific information on the valorisation of agri-food waste to which innovative and efficient techniques and technologies have been applied, resulting in natural resource use in new products. Our review aims to explore and assess the production, development and industrial exploitation of renewable biological resources as a way to bridge the transition from the linear economic model to a circular bioeconomy (CBE) paradigm shift. For a detailed exploration and assessment of the research problem, this paper presents a comparative study between two paradigmatic projects organised and financed by different R&D programmes of the European Union (EU). We identify the agents and strategies of a potential BC innovation system, and we propose a conceptual model for the creation of an innovative and alternative industrial-scale productive value chain to replace petrochemical-based composite materials with BC and establish a new paradigm of production and consumption.
