Validation through finite element simulation of the behaviour of a polyurethane shock absorber under in-service and extreme conditions

ABSTRACT: The safety rules for the construction and installation of lifts, currently in force in Europe, include several requirements concerning the behaviour of the shock absorbers when stopping an elevator. In this paper, a finite element model simulating the behaviour of a cellular polyurethane shock absorber has been developed. The material mechanical behaviour was simulated by means of an elastomeric foam theoretical model, previously calibrated in a former paper. Several in-service and extreme condition scenarios have been analysed with this numerical model, thus verifying the fulfilment of the requirements of the standard

Characterization of mechanical properties of a shock absorber polyurethane foam for elevators. Numerical fitting of mechanical behavior models for hyperelastic and elastomeric foam materials

ABSTRACT: The elastic cellular polyurethane elastomer is widely used to manufacture shock absorbers for elevators, due to its excellent conditions for absorption of energy and vibration damping. In this paper, a complete mechanical characterization of this material was performed including the uniaxial compressive test, the planar test, and the volumetric and the simple shear test. From the experimental results, several models of behavior for hyperelastic and elastomeric foam materials have been analyzed by fitting their corresponding material parameters. The scope of this work includes the Ogden model, the Van der Waals model, and polynomial and elastomeric foam forms

Fully-Convolutional Denoising Auto-Encoders for NILM in Large Non-Residential Buildings

[EN] Great concern regarding energy efficiency has led the research community to develop approaches which enhance the energy awareness by means of insightful representations. An example of intuitive energy representation is the parts-based representation provided by Non-Intrusive Load Monitoring (NILM) techniques which decompose non-measured individual loads from a single total measurement of the installation, resulting in more detailed information about how the energy is spent along the electrical system. Although there are previous works that have achieved important results on NILM, the majority of the NILM systems were only validated in residential buildings, leaving a niche for the study of energy disaggregation in non-residential buildings, which present a specific behavior. In this paper, we suggest a novel fully-convolutional denoising auto-encoder architecture (FCN-dAE) as a convenient NILM system for large non-residential buildings, and it is compared, in terms of particular aspects of large buildings, to previous denoising auto-encoder approaches (dAE) using real electrical consumption from a hospital facility. Furthermore, by means of three use cases, we show that our approach provides extra helpful funcionalities for energy management tasks in large buildings, such as meter replacement, gap filling or novelty detection.SIThis work was supported by the Principado de Asturias Government through the Predoctoral Grant “Severo Ochoa.” Paper no. TSG-00737-202

Study of the microbiota associated to Ruditapes decussatus and Ruditapes philippinarum clams by 16S rRNA metabarcoding, dilution to extinction, and culture-based techniques

The study of the microbiota associated to clams is important not only to know their sanitary status but also to prevent pathobiology events. The use of different microbiological techniques can help to obtain a better picture of the bacterial diversity of clams as well as to isolate new bacterial taxa. In this study, two clam species, Ruditapes decussatus and R. philippinarum, were analyzed in two locations of Galicia (northwest of Spain) in April and October, by combining classic culturing, dilution-to-extinction approach, and 16S rRNA gene target sequencing. 16S rRNA gene target sequencing revealed a great diversity within the clam samples, shedding light into the vast microbial communities associated to these bivalves. All samples were dominated by the same bacterial genera in the different periods, namely Mycoplasma, Vibrio, and Cutibacterium. The α-diversity in the samples obtained during the month of October was lower and showed the dominance of rare bacterial taxa, such as Methylobacterium or Psychrobacter. Dilution-to-extinction technique demonstrated its usefulness to culture rare bacterial taxa that were not found in clams under the classic culturing techniques, including Rahnella, Brachybacterium, Micrococcus, Jantinobacter, and Lelliottia. Altogether, our study provides valuable information on the microbiota associated to R. decussatus and R. philippinarum, demonstrating the high complexity and dynamics of these microbial populationsOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported in part by grant AGL2013-42628-R and AGL2016-77539-R from the Ministerio de Economía y Competitividad (Spain)S

Influence of elastomeric matrix and particle volume fraction on the mechanical response of magneto-active polymers

Magneto-active polymers (MAPs) are revolutionising the fields of material science and solid mechanics as well as having an important presence in the bioengineering community. These composites consist of a polymeric matrix (i.e., elastomer) filled with magnetic particles (i.e., iron particles). When bonded together, these two phases form a continuum solid that, under the application of an external magnetic field, mechanically reacts leading to changes in shape and volume or/and alterations in its rheological properties. Such a magneto-mechanical response is determined by the material properties of the polymeric matrix and magnetic particles. In this work, we present the mechanical characterisation of MAPs constituted by PDMS filled with carbonyl iron powder (CIP) particles. To this end, sixteen different combinations of elastomeric base/crosslinker mixing ratio (from 5:1 to 20:1) and particles' volume fraction (from 0% to 30%) are tested under tensile loading. These results are analysed and provide the bases for the formulation of a nonlinear constitutive model that accounts for these dependencies. The modelling approach is extended to incorporate magneto-mechanical effects. Finally, the complete model is used to provide theoretical guidance for magneto-active systems, highlighting potential applications in epithelial wound healing stimulation.DGG, DV and MAM acknowledge support from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 947723,project: 4D-BIOMAP). The authors acknowledge support from Programa de Apoyo a la Realización de Proyectos Interdisciplinares deI+D para Jóvenes Investigadores de la Universidad Carlos III de Madrid and Comunidad de Madrid, Spain (project: BIOMASKIN). DGG acknowledges support from the Talent Attraction grant (CM 2018 -2018-T2/IND-9992) from the Comunidad de Madrid and MAM acknowledges support from the Ministerio de Ciencia, Innovacion y Universidades, Spain (FPU19/03874)

RAD51 restricts DNA over-replication from re-activated origins

Eukaryotic cells rely on several mechanisms to ensure that the genome is duplicated precisely once in each cell division cycle, preventing DNA over-replication and genomic instability. Most of these mechanisms limit the activity of origin licensing proteins to prevent the reactivation of origins that have already been used. Here, we have investigated whether additional controls restrict the extension of re-replicated DNA in the event of origin re-activation. In a genetic screening in cells forced to re-activate origins, we found that re-replication is limited by RAD51 and enhanced by FBH1, a RAD51 antagonist. In the presence of chromatin-bound RAD51, forks stemming from re-fired origins are slowed down, leading to frequent events of fork reversal. Eventual re-initiation of DNA synthesis mediated by PRIMPOL creates ssDNA gaps that facilitate the partial elimination of re-duplicated DNA by MRE11 exonuclease. In the absence of RAD51, these controls are abrogated and re-replication forks progress much longer than in normal conditions. Our study uncovers a safeguard mechanism to protect genome stability in the event of origin reactivation

Tuning the cell and biological tissue environment through magneto-active materials

This review focuses on novel applications based on multifunctional materials to actuate biological processes. The first section of the work revisits the current knowledge on mechanically dependent biological processes across several scales from subcellular and cellular level to the cellcollective scale (continuum approaches). This analysis presents a wide variety of mechanically dependent biological processes on nervous system behaviour; bone development and healing; collective cell migration. In the second section, this review presents recent advances in smart materials suitable for use as cell substrates or scaffolds, with a special focus on magneto-active polymers (MAPs). Throughout the manuscript, both experimental and computational methodologies applied to the different treated topics are reviewed. Finally, the use of smart polymeric materials in bioengineering applications is discussed.This work has been supported by the Madrid Government (Comunidad de Madrid) under the Multiannual Agreement with UC3M in the line of "Fostering Young Doctors Research" (BIOMASKIN-CM-UC3M), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation, and support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 947723). DGG acknowledges support from the Talent Attraction grant (CM 2018-2018-T2/IND-9992) from the Comunidad de Madrid.Publicad

Network flow based approaches for the pipelines routing problem in naval design

In this paper we propose a general methodology for the optimal automatic routing of spatial pipelines motivated by a recent collaboration with Ghenova, a leading Naval Engineering company. We provide a minimum cost multicommodity network flow based model for the problem incorporating all the tech- nical requirements for a feasible pipeline routing. A branch-and-cut approach is designed and different matheuristic algorithms are derived for solving efficiently the problem. We report the results of a battery of computational experiments to assess the problem performance as well as a case study of a real-world naval instance provided by our partner company.Ministerio de Ciencia Y Tecnología (MCYT). España PID2020-114594GB-C21European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER) US-1256951Junta de Andalucía P18-FR-1422Junta de Andalucía CEI-3-FQM331Junta de Andalucía B-FQM-322-UGR2

Organizaciones autónomas descentralizadas (DAOs) para economía colaborativa utilizando Blockchain

Este trabajo consiste en la creación de un modelo de Organización Autónoma Descentralizada (DAO) sobre Blockchain para sociedades con un estilo de economía colaborativa. A diferencia de otras aplicaciones nuestro trabajo está realizado de manera que, no sólo se pueda aplicar a un tipo de organización como el que hemos hecho de ejemplo (Guerrilla developers) sino que, está hecho para que sirva de modelo para cualquier organización que tenga un sistema de roles en los que se necesite hacer ciertos méritos para poder ascender en la organización. La aplicación está desarrollada sobre Aragon, que es un framework que trabaja sobre Ethereum. El uso de Aragon facilita la creación de estas organizaciones ya que cuenta con funcionalidades que son de gran ayuda como sistema de votación o gestión de tokens. Ethereum es una plataforma digital que utiliza la tecnología de cadena de bloques (blockchain) desarrollada para Bitcoin y expande su uso a distintos tipos de aplicaciones. El uso de este tipo de tecnología evita la necesidad de que todo el sistema de gestión este centralizado y que se deposite la confianza en una sola autoridad

Visualization Processes in a Task that Requires Generating and Representing Solids of Revolution

En este trabajo se analizaron los procesos de visualización implicados en una tarea que requiere generar y representar cuerpos de revolución. La tarea se administró a cuatrocientos estudiantes del grado de maestro de Educación Primaria. Se adoptó como marco teórico el enfoque Ontosemiótico de la Instrucción y el Conocimiento Matemáticos, utilizándose como herramienta analítica la noción de configuración en su vertiente epistémica y cognitiva. Para el análisis de datos se empleó una metodología de investigación mixta: con una componente cualitativa que evaluó las categorías de objetos primarios, y otra cuantitativa que categorizó el grado de corrección de las respuestas. El análisis de los procesos de visualización se realizó por medio de las nueve configuraciones cognitivas identificadas en las soluciones de los estudiantes. Los errores de resolución se concentraron más en el procesamiento visual de la información que en el proceso de interpretación de la información figurativa. La mayoría de ellos se debieron a dificultades para movilizar las habilidades de reconocimiento de relaciones y posiciones espaciales, observándose una correspondencia entre la efectividad de las configuraciones cognitivas y la representación externa de los cuerpos generados.In this work we analyzed the visualization processes involved in a mathematical task that requires generating and representing solids of revolution. The task was administered to four hundred university students from the Bachelor's Degree in Primary Education. We adopted the Ontosemiotic Approach to Mathematical Instruction and Knowledge as a theoretical framework, using the configuration notion as an analytical tool in both its epistemic and cognitive aspects. For the data analysis, we used a mixed method approach: a qualitative dimension evaluating the primary objects categories, and a quantitative dimension categorizing the answers' success degree. The visualization processes analysis was done via the nine cognitive configurations identified from the students' solutions. The resolution errors focused more on the visual processing than on the interpreting figurative information processing. The majority of these errors were due to difficulties in mobilizing the recognition's abilities of spatial relations and positions, observing a correspondence between the effectiveness of cognitive configurations and the external representation of the generated solids.Trabajo financiado por el proyecto STEM4youth: Promotion of Stem Education by Key Scientific Challenges and their Impact on our Life and Career Perspectives, Programa Horizon 2020 (H2020- Seac-2015-1-710577) y por FEDER/Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación/ _Proyecto EDU2017-84979-R