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Documentos de las investigaciones financiadas por la UE dentro del Séptimo Programa Marco (7º PM) y del Consejo Europeo de Investigación (CEI), en el marco del Proyecto OpenAIRE que promueve el acceso abierto en Europa
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- PublicaciónA Review of Broadband Frequency Techniques for Insulation Monitoring and Diagnosis in Rotating Electrical Machines(Institute of Electrical and Electronics Engineers, 2024-08) Ruiz Sarrió, José Enrique; Antonino Daviu, José Alfonso; Navarro Navarro, Ángela; Biot Monterde, Vicente; Instituto de Tecnología Eléctrica; Departamento de Ingeniería Eléctrica; Escuela Técnica Superior de Ingeniería Industrial; European Commission; Universitat Politècnica de València[EN] Rotating electrical machines greatly suffer from insulation degradation and failure. The adoption of wide bandgap semiconductors in Variable-Frequency Drives (VFDs) hinder the utilization of traditional techniques such as on-line Partial Discharges (PD) to monitor and diagnose the insulation status and failure. Alternative techniques exploiting the broadband frequency behaviour of machine windings, and the increased high-frequency content of VFD excitation arise as a valid alternative. The present work provides a comprehensive analysis and review of cutting-edge broadband frequency techniques aimed to diagnose winding insulation degradation and faults. First, the broadband nature of machine windings is illustrated by explaining the per-turn equivalent circuit and the physical interpretation of its parameters. Then, the different insulation monitoring and diagnosis methods are thoroughly reviewed. The analysed methods include the Frequency Response Analysis (FRA) applied to rotating electrical machines, the analysis of Common Mode (CM) broadband impedance and parasitic capacitances, and methodologies based on the analysis of transient high-frequency current ringing. Specific focus is placed on the instrumentation, which often represents the main applicability limitations.
- PublicaciónOn the Oral Microbiome of Oral Potentially Malignant and Malignant Disorders: Dysbiosis, Loss of Diversity, and Pathogens Enrichment(MDPI AG, 2023-02) Herreros Pomares, Alejandro; Hervás Marín, David; Bagán-Debón, Leticia; Jantus Lewintre, Eloisa; Gimeno-Cardona, Concepción; Bagan, José; Departamento de Estadística e Investigación Operativa Aplicadas y Calidad; Departamento de Biotecnología; Centro Avanzado de Microbiología Aplicada; Escuela Politécnica Superior de Alcoy; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Instituto de Salud Carlos III[EN] The role of dysbiosis in the development and progression of oral potentially malignant disorders (OPMDs) remains largely unknown. Here, we aim to characterize and compare the oral microbiome of homogeneous leucoplakia (HL), proliferative verrucous leukoplakia (PVL), oral squamous cell carcinoma (OSCC), and OSCC preceded by PVL (PVL-OSCC). Fifty oral biopsies from HL (n = 9), PVL (n = 12), OSCC (n = 10), PVL-OSCC (n = 8), and healthy (n = 11) donors were obtained. The sequence of the V3-V4 region of the 16S rRNA gene was used to analyze the composition and diversity of bacterial populations. In the cancer patients, the number of observed amplicon sequence variants (ASVs) was lower and Fusobacteriota constituted more than 30% of the microbiome. PVL and PVL-OSCC patients had a higher abundance of Campilobacterota and lower Proteobacteria than any other group analyzed. A penalized regression was performed to determine which species were able to distinguish groups. HL is enriched in Streptococcus parasanguinis, Streptococcus salivarius, Fusobacterium periodonticum, Prevotella histicola, Porphyromonas pasteri, and Megasphaera micronuciformis; PVL is enriched in Prevotella salivae, Campylobacter concisus, Dialister pneumosintes, and Schaalia odontolytica; OSCC is enriched in Capnocytophaga leadbetteri, Capnocytophaga sputigena, Capnocytophaga gingivalis, Campylobacter showae, Metamycoplasma salivarium, and Prevotella nanceiensis; and PVL-OSCC is enriched in Lachnospiraceae bacterium, Selenomonas sputigena, and Prevotella shahii. There is differential dysbiosis in patients suffering from OPMDs and cancer. To the best of our knowledge, this is the first study comparing the oral microbiome alterations in these groups; thus, additional studies are needed.
- PublicaciónThe role of the interfaces and cross-links on the mechanical behavior of mineralized collagen fibrils. A numerical approach(Elsevier, 2024-10-01) Vercher Martínez, Ana; Giner Maravilla, Eugenio; Fuenmayor Fernández, Francisco Javier; García-Aznar, J. Manuel; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Departamento de Ingeniería Mecánica y de Materiales; Instituto Universitario de Investigación Concertado de Ingeniería Mecánica y Biomecánica; Escuela Técnica Superior de Ingeniería Industrial; GENERALITAT VALENCIANA; AGENCIA ESTATAL DE INVESTIGACION; Agencia Estatal de Investigación; Universitat Politècnica de València[EN] Mechanical properties of bone tissue are highly dependent on its hierarchical structure. The presence of microcracks and diffuse damage in lamellar bone is correlated with the failure of the collagen-mineral interface in mineralized collagen fibrils (MCF). The main goal of this work is to evaluate the mechanical behavior of the interfaces and quantify the stiffness loss of the MCF associated with different failure mechanisms, under controlled in-plane displacement. Additionally, we aim to study the role of the cross-links on the fibril mechanical response, beyond the interface failure. Inter- and intra-microfibrilar cross-links are analyzed. In order to address the first issue, a detailed representative volume of the MCF is analyzed by means of the finite element method, under the assumption of plane strain and periodic boundary conditions. In this model the interfaces between constituents are modeled with an exponential cohesive law. Enzymatic cross-links, located at the molecular terminals connecting each 4D (D = 67 nm) staggered molecules, are represented by non-linear springs. Three in-plane controlled deformations are applied. The results of this work provide the anisotropic stiffness loss of the tissue involved in the different failure mechanisms at the nano-scale length. The initiation of microcracks and the presence of damage zones are compatible with the failure mechanisms observed at interfaces. Interface failure entails a progressive stiffness loss, bringing a non-linear behavior of bone. The strength obtained for the longitudinal maximum deformation is more than 20 times the transverse strength and 3.5 times the shear strength. The quantification of the reduction percentage in the elastic moduli and the shear stiffness when the fibril is damaged, has a potential application in improving failure criteria based on degradation of elastic constants. When longitudinal elongation is applied, the mechanical contribution of the cross-links in delaying the failure initiation of the interface is shown. Likewise, results of this work confirm the scarce influence of the cross-links in the strain range analyzed. Additionally, a threedimensional numerical model of several microfibrils is defined with the aim of analyzing the mechanical relevance of inter- and intra-microfibrilar cross-links, beyond the interface failure. Results confirm that cross-links transfer the load when strain increases, being highlighted the mechanical competence of the trivalent cross-links.
- PublicaciónAnalysis of stress intensity factor oscillations in 3D cracks using domain integrals and the extended finite element method(Elsevier, 2025-03) González Albuixech, Vicente Francisco; Giner Maravilla, Eugenio; Gravouil, Anthony; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Departamento de Ingeniería Mecánica y de Materiales; Instituto Universitario de Investigación Concertado de Ingeniería Mecánica y Biomecánica; Generalitat Valenciana; European Regional Development Fund; Ministerio de Ciencia e Innovación[EN] Fracture-related failure of structural integrity can be evaluated using stress intensity factors (SIFs), and complex fractured geometries can be modeled using the extended finite element method (XFEM). Typically, domain integrals - especially J-integrals and interaction integrals - are used to compute SIFs. Although these integrals produce accurate estimates with the finite element method, they exhibit oscillations in the finite element support mesh when using XFEM due to their sensitivity to various topological relationships between the enrichment zone, domain definition and mesh. These oscillations can jeopardize accuracy, stability, and robustness of XFEM, influencing the convergence rate of SIFs. The domain integration solution has already undergone several changes to reduce these impacts, but no comparison or consideration of topological influence has been made. Here, we study some of the elements that lead to the unwanted behavior observed in various domain integration definitions, which incorporate corrections for curved and nonplanar cracks in examples with relatively coarse meshes. Consequently, various methodological limitations are discussed along with recommendations and suggestions.
- PublicaciónBest estimate plus uncertainty methodology for forecasting electrical balances in isolated grids: The decarbonized Canary Islands by 2040(Elsevier, 2024-05) Berna Escriche, César; Rivera-Durán, Yago; Álvarez Piñeiro, Lucas; Muñoz-Cobo González, José Luís; Departamento de Estadística e Investigación Operativa Aplicadas y Calidad; Instituto Universitario de Investigación de Ingeniería Energética; Escuela Técnica Superior de Ingeniería Industrial; Escuela Técnica Superior de Ingeniería Informática; Universitat Politècnica de València; Ministerio de Economía, Industria y Competitividad[EN] This paper investigates the challenges isolated islands face in transitioning from fossil fuel-based electricity generation to renewable energy sources. The Canary Islands serve as a case study, where photovoltaic and wind power are the primary renewables, but their variability requires a deep techno-economic analysis. The island¿s energy demand is predicted to rise by 100% due to economic growth, electrification and electric vehicles. However, implementing renewable systems encounters obstacles, such as limited suitable sites and protected areas. The study uses Wilks¿ methodology and Monte Carlo sampling to explore 59 combinations of randomly selected inputs of the uncertain variables, aiming for a 95/95% coverage and confidence level in the results. In most cases, they experience energy shortages, failing to meet electric demand. Even though a new generation mix appears to cover demand under all circumstances, the uncertainty unveils a different reality, leading to an approximate 25% increase in system costs. Surpluses in energy generation, while seemingly positive, can pose challenges. The new system¿s Levelized Cost of Energy increases from around 14 to 17c€/kWh. These cost increases are contingent upon future performance and the variability of uncertain parameters, leading to excesses ranging from slightly below 25% to over 40%.