Multiparticie aggregation model for dendritic growth applied to experiments on amorphous Co-P alloys

We introduce a multiparticle biased diffusion limited aggregation model for dendritic growth. Its most relevant feature is that it includes the overall effect of strong applied electric fields and therefore applies to nonequilibrium situations. We compare simulations of a two species version of our model to actual experiments on preparation of amorphous Co-P alloys with very good agreement: The model accurately reproduces the dependence of composition, morphology, and growth time of the alloy on the current. We conclude with a discussion of specific predictions and possible generalizations of the model.Supported by DGICyT (Spain) through Grant No. PB92-0248 and by MEC/Fulbright. MJ.B. and J.M.R. acknowledge support from DGICyT (Spain) Grant No. MAT91-0031. Work at Los Alamos is performed under the auspices of the V.S. D.O.E.Publicad

Biomimetic electrochemical sensor integrated in flexible polymeric devices for cancer diagnosis

The authors gratefully acknowledge to the project IBEROS, Instituto de Bioingeniería en Red para el Envejecimiento Saludable, PROGRAMA INTERREG 2014-2020, reference POCTEP/0245_IBEROS_1_E and the financial support to CANCER Project through Norte 2020 – Programa Operacional Regional do Norte, reference NORTE-01-0145-FEDER-000029.info:eu-repo/semantics/publishedVersio

Fabrication and deposition of copper and copper oxide nanoparticles by laser ablation in open air

The proximity of the “post-antibiotic era”, where infections and minor injuries could be a cause of death, there are urges to seek an alternative for the cure of infectious diseases. Copper nanoparticles and their huge potential as a bactericidal agent could be a solution. In this work, Cu and Cu oxide nanoparticles were synthesized by laser ablation in open air and in argon atmosphere using 532 and 1064 nm radiation generated by nanosecond and picosecond Nd:YVO4 lasers, respectively, to be directly deposited onto Ti substrates. Size, morphology, composition and the crystalline structure of the produced nanoparticles have been studied by the means of field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), the energy dispersive spectroscopy of X-rays (EDS), selected area electron diffraction (SAED) and X-ray diffraction (XRD). The UV-VIS absorbance of the thin layer of nanoparticles was also measured, and the antibacterial capacity of the obtained deposits tested against Staphylococcus aureus. The obtained deposits consisted of porous coatings composed of copper and copper oxide nanoparticles interconnected to form chain-like aggregates. The use of the argon atmosphere contributed to reduce significantly the formation of Cu oxide species. The synthesized and deposited nanoparticles exhibited an inhibitory effect upon S. aureus.Peer ReviewedPostprint (published version

Relaciones entre las dimensiones de las actitudes hacia las matemáticas en futuros maestros

En este trabajo se estudian las relaciones entre distintas dimensiones de las actitudes hacia las Matemáticas de los estudiantes del Grado en Educación Primaria de la Universidad de A Coruña del 1.er y 3.er curso recogidas durante tres años académicos consecutivos. Para ello se aplica el cuestionario de actitudes PAC de Naya-Riveiro, Soneira, Mato y Torre (2014) con una fiabilidad Alfa de Cronbach de 0.921 a una muestra de 308 estudiantes. El instrumento está formado por 19 ítems con cinco opciones de respuesta tipo Likert y tres dimensiones que miden el autoconcepto, la percepción que tiene el alumno de su profesor y el agrado hacia las Matemáticas. Los resultados muestran que existe una relación monótona creciente entre las distintas dimensiones de las actitudes en ambos cursos y que éstas se mantienen de un curso a otro

ICES. 2021. Working Group on Southern Horse Mackerel Anchovy and Sardine (WGHANSA).

The ICES Working Group on Southern horse mackerel, anchovy and sardine (WGHANSA) assessed the status of anchovy in Atlantic Iberian waters (ane.27.9a; western and southern components) and horse mackerel in Atlantic Iberian waters (hom.27.9a) in the May meeting and of anchovy in Bay of Biscay (ane.27.8), sardine in southern Celtic Seas and the English Channel (pil.27.7), sardine in Bay of Biscay (pil.27.8abd) and sardine in Cantabrian Sea and Atlantic Iberian waters (pil.27.8c9a) in the November meeting. In addition, to answer a special request from Portugal and Spain, in May the working group updated the assessment of sardine in Atlantic Iberian waters (pil.27.8c9a) based on the most recent data available and included as catch scenarios, the harvest control rule evaluated in the Workshop for the evaluation of the Iberian sardine harvest control rules (WKSARHCR 2021). Deviations from the stock annex caused by missing surveys and deteriorated catch data due to the Covid-19 were described and sensitivity analyses of their impact were provided whenever possibl

Learning from failure propagation in steel truss bridges

Although truss-type bridge collapses usually have catastrophic consequences, their analysis present opportunities for improving different aspects in the field of bridge engineering, such as structural assessment, structural health monitoring, maintenance and conservation or even design strategies. As the world experiences more extreme events, efforts have been made to design more resilient bridges that can withstand local failures. Forensic techniques have contributed to understanding the causes and risk factors of bridge failures, and the creation of collapse databases has provided valuable insights for preventing such failures. However, these databases often focus on the hazards and do not provide information on initial damage and how it propagates, which is essential for improving the progressive collapse resistance of truss-type bridges. The main novelty of this paper is to present a methodology to identify triggering events leading to progressive collapse on truss-type bridges. It is the first time that a methodology includes a novel database which collects detailed information on initial damages and its propagation, as well as the consequences of the collapse. The methodology was implemented by collecting information from 25 case studies present in the literature. Results have allowed to identify most frequent initial constituted damages states or failures (ICDS) leading progressive collapse. In terms of consequences, results were thoroughly analysed and compared with predictions from different casualty models. The findings showed that the proposed methodology serves as an effective tool for identifying the triggering events of progressive collapse in truss-type bridges.Agencia Estatal de Investigación | Ref. PID2021-124236OBAgencia Estatal de Investigación | Ref. FJC2020–046370-IUniversidade de Vigo/CISU

Initiation and propagation of failures in steel truss bridges

Bridge collapses are catastrophic events with countless consequences. However, bridge engineering has progressed thanks to the knowledge acquired analyzing collapsed structures. In this direction, modern forensic techniques allow detecting weaknesses and vulnerable zones in the structural systems. It has been demonstrated that the data related to bridge failures has been fundamental for engineers to propose and update theories, concepts, and designs in bridge engineering. This paper presents a methodology to analyze the initial damage and its propagation on steel truss bridges. The first part of the paper presents a comprehensive review of state‐of‐the‐art and scientific challenges. The methodology is described in detail in the second part of the paper; it comprises two main tasks that are further divided into several activities. This methodology was developed as part of the “Pont3” project and has proven to be of great value in gaining a better understanding of how progressive collapse occurs in steel truss bridges. By using this methodology, it is possible to detect initial damage and evaluate the structural behavior of steel truss bridges, which will ultimately lead to safer and more reliable structures.Universidade de Vigo/CISU

Preventing failure propagation in steel truss bridges

[EN] Metal and steel truss bridges are essential for transportation networks worldwide but are vulnerable to collapse due to deterioration and increasing traffic loads, par-ticularly for ageing structures. Several bridge collapses, such as the Seongsu bridge (South Korea, 1994), I-35 bridge (USA, 2007), and Chauras bridge (India, 2012), have highlighted the need to develop accurate robustness assessment strategies and efficient mitigation of collapse risks. This paper summarizes results of experi-mental and computational studies for a steel riveted bridge with a truss-type struc-ture. The experimental component presented involves unique tests to be performed on a 21 m full-scale bridge span subjected to the failure of different elements under laboratory conditions. The paper then presents a first approach to explore different damage and failure scenarios for steel truss bridges, which will assist in defining data collection strategies for optimised monitoring and developing data analysis methods for real-time diagnosis of ageing bridges. With this, the paper contributes to avoiding progressive collapses and presents a framework, developed as part of an ongoing project, to identify vulnerable zones for prioritising monitoring systems that anticipate failure propagation and prevent collapse. The framework is based on a systematic analysis of past bridge failures and simulations of carefully designed generic cases.Sánchez-Rodríguez, A.; López, S.; Makoond, NC.; Buitrago, M.; Riveiro, B.; Adam, JM. (2023). Preventing failure propagation in steel truss bridges. Ernst & Sohn, Wiley Online Library. 2206-2213. https://doi.org/10.1002/cepa.23772206221