Security and defence of mobile systems under impact

The Group “Dynamics and Fracture of Structural Elements” offers its experience in Solid Mechanics analysis for the study of the impact protection of vehicles, aircrafts and persons. The Group activities have a strong research component, in which numerical simulation tools as well as sophisticated experimental techniques are employed. This technological offer could be of interest to automobile companies (impact and collision security), aeronautical companies (impact of external body on fuselage, attack, and fragments o ice) and defence companies (special armours for mobile systems and persons).Contrato Programa de Comercialización e Internacionalización. Sistema Regional de Investigación Científica e Innovación Tecnológica. (Comunidad de Madrid; Universidad Carlos III de Madrid

Les portes al riu

El projecte parteix d'un encàrrec per part de l'Ajuntament de Sallent de Llobregat, la millora de les lleres del riu al seu pas pel nucli urbà. Posterior a una anàlisi urbanístic de la zona determinem que el millor àmbit a on actuar és la Plaça 19 d'Abril i el seu entorn, ja que és un gran espai de relació riu-poble urbanitzat però que presenta grans dèficits a causa de l'ús que se li dóna, un aparcament informal. Aquest punt, a més, suposa una interrupció dels traçats de gran recorregut que creuen el municipi. El projecte, "Les portes al riu", mitjançant estratègies de deconstrucció i canvi d'us retornarà aquest espai al poble com una zona de rebuda al riu i el punt de connexió amb el parc fluvial. El projecte es divideix en tres actuacions, l'aparcament, la baixada al fluvial i el parc esportiu urbà. Actualment aquesta àmplia zona s'utilitza com a aparcament informal, envaint tot l'espai, la primera actuació serà posar ordre a aquest aparcament per tal d'alliberar altres zones de la plaça. Amb aquesta actuació també es crearan zones d'estada que valorin els elements patrimonials existents a l'àmbit. La segona actuació és la millora de la baixada al parc fluvial, l'àmbit natural més gran del municipi. Es fa una neteja i arranjament de la zona mantenint el caràcter rural del camí. L'última actuació a realitzar és un Parc esportiu urbà. A la zona superior de la plaça se situen 2 mòduls de patinatge amb un ús molt intensiu de patinadors. Un cop aquesta part de la plaça s'ha alliberat de vehicles es planteja construir un parc esportiu urbà, millorant les condicions dels patinadors alhora que la qualitat de la plaça. S'allibera l'espai per poder dur a terme activitats de poble sense que aquestes no entrin en conflicte amb els skaters

Donoso Cortés und Ernst Ludwig von Gerlach : ein Beitrag zum politisch-theologischen Konservativismus des 19. Jahrhunderts

Es handelt sich um eine Untersuchung über die staatsphilosophischen Gemeinsamkeiten und Unterschiede zwischen dem spanischen gegenrevolutionären Juan Donoso Cortés und Ernst Ludwig von Gerlach

A new constitutive model for polymeric matrices: Application to biomedical materials

Semi crystalline polymeric composites are increasingly used as bearing material in the biomedical sector, mainly because of their specific mechanical properties and the new advances in 3D printing technologies that allows for customised devices. Among these applications, total or partial prostheses for surgical purposes must consider the influence of temperature and loading rate. This paper proposes a new constitutive model for semi-crystalline polymers, commonly used as matrix material in a wide variety of biomedical composites, that enables reliable predictions under a wide range of loading conditions. Most of the recent models present limitations to predict the non-linear behaviour of the polymer when it is exposed to large deformations at high strain rates. The proposed model takes into account characteristic behaviours of injected and 3D printed thermoplastic polymers such as material hardening due to strain rate sensitivity, thermal softening, thermal expansion and combines viscoelastic and viscoplastic responses. These viscous-behaviours are relevant for biomedical applications where temperature evolution is expected during the deformation process due to heat generation induced by inelastic dissipation, being essential the thermo-mechanical coupling consideration. The constitutive model is formulated for finite deformations within a thermodynamically consistent framework. Additionally, the model is implemented in a finite element code and its parameters are identified for two biomedical polymers: ultra-high-molecular-weight polyethylene (UHMWPE) and high density polyethylene (HDPE). Finally, the influence of viscous behaviours on dynamic deformation of semi-crystalline polymeric matrices is analysed

A continuum constitutive model for FDM 3D printed thermoplastics

Fused deposition modelling (FDM) is the most common additive manufacturing technology used for thermoplastic components. This layers-based manufacturing process results into direct links between printing parameters and the polymer mesostructure by means of porosity and structural anisotropy. These dependencies along with other features of thermoplastic polymers (i.e., nonlinearities, viscous and thermal responses) makes its constitutive modelling very challenging. This work distances from studies that model the 3D printing process. Instead, we aim at complementing such approaches with a continuum model to describe the macroscopic behaviour of FDM thermoplastics while preserving links with printing parameters. Prior to the modelling conceptualisation, experimental characterisation tests are conducted on ABS specimens to evaluate the influence of printing parameters on the macroscopic mechanical response. The physical fundamentals behind the deformation and failure mechanisms are identified and motivate the new constitutive model. This model is formulated for finite deformations within a thermodynamically consistent framework. The model accounts for: nonlinear response; anisotropic hyperelasticity related to a transversely isotropic distribution of porous; strain rate dependency; macroscopic stiffness dependent on 3D printing processing. Finally, the model is numerically implemented and calibrated for ABS with original experiments, demonstrating its suitability.The authors acknowledge support from Ministerio de Ciencia, Innovación y Universidades, Spain, Agencia Estatal de Investigación y Fondo Europeo de Desarrollo Regional, Spain, como entidades financiadoras (RTI2018-094318-B-I00). D.G.-G., S.G.-H. and A.A. acknowledge support from Programa de Apoyo a la Realización de Proyectos Interdisciplinares de I+D para Jóvenes Investigadores de la Universidad Carlos III de Madrid (BIOMASKIN-CM-UC3M). D.G.-G. acknowledges support from the Talent Attraction grant (CM 2018 - 2018-T2/IND- 9992) from the Comunidad de Madrid, Spain

Multi-impact mechanical behaviour of short fibre reinforced composites

High velocity transverse impact on reinforced composites is a matter of interest in the automotive, aeronautical and biomedical sectors. Most existing studies have addressed this problem by single isolated impacts; however, this work deals with the distinction between single, sequential and simultaneous impacts on composite structures. This paper proposes an experimental methodology to study the mechanical behaviour of materials under single and multi-impact loadings. The overall objective is to investigate the mechanical response of short carbon fibre reinforced PEEK when is subjected to single and multiple high velocity impacts. Experimental tests are conducted covering impact velocities from 90 m/s to 470 m/s. Energy absorption, damage extension and failure mechanisms are compared to assess additive and cumulative effects in high velocity impact scenarios. Experimental results show that the specific deformation and fracture mechanisms observed during multi-hitting events change with impact velocity. Compared to the behaviour of unreinforced thermoplastics, short fibre reinforced composites present significant limitations at velocities close to the ballistic limit, but multi-hit capability is observed at high impact velocity when the damage is mainly local. As key conclusion, the ballistic limit obtained in single impact test cannot be extrapolated to sequential and simultaneous tests. Multi-impact tests, especially close to the ballistic limit, are necessary to guarantee the structural integrity of composite structures in realistic impact scenarios.The researchers are indebted to Ministerio de Economía y Competitividad de España (Project DPI2014-57989-P) and Vicerrectorado de Política Científica UC3M (Project 2013-00219-002) for financial support

Establecimiento in vitro de Bambusa vulgaris (Bambú amarillo).

Proyecto de Graduación (Bachillerato en Ingeniería en Biotecnología) Instituto Tecnológico de Costa Rica. Escuela de Biotecnología, 2001.La especie Bambusa vulgaris (bambú) representa un recurso de suma importancia para la industria del papel, la artesanía y la construcción, sin embargo las técnicas tradicionales de propagación no permiten la multiplicación en corto tiempo. El cultivo de tejidos representa una opción para la propagación de B. vulgaris. En la presente investigación tiene como objetivo el establecimiento aséptico in vitro de la especie mencionada. Para ello se realizaron ensayos con tres diferentes explantes: meristemos de tallo, meristemos de rizoma y entrenudos; se aplicaron múltiples tratamientos de desinfección con cloro, alcohol, antibióticos, fungicidas y bactericidas en medios de cultivo MS (1962), a pH 5,7 sin antioxidante, con PVP o carbón activado, en estado sólido o líquido, 20 % de sacarosa. Los meristemos de rizoma respondieron mejor a la desinfección y condiciones in vitro, presentando una oxidación controlable al utilizar medio líquido complentado con Carbón activado (1g/L). Los meristemos apicales se oxidaron en su totalidad. Los entrenudos presentaron una contaminación total por hongos pero no oxidación. El tratamiento que resultó efectivo para la desinfección y control de la oxidación fue aquel en el que se empleó 1 hora mixto Amoxicilina (100mg/L), Ampicilina (100mg/L) y Kilol y Kasumin 1:1 (2 ml/l), 10 minutos en alcohol al 70%, 3 lavados en cámara en medio líquido MS a la mitad complementado con carbón activado

¡Adaptarse o morir! Una revisión sistemática de la literatura sobre renovación estratégica y empresa familiar :

The objective of this paper is to examine the current state of strategic renewal research in family businesses, identifying the main research gaps and providing a path for future research to the academics. To do so, we have performed a systematic and comprehensive review of 21 studies (20 articles and 1 book chapter) about strategic renewal and family business published between 2009 and 2022. Our comprehensive analysis reveals that the majority of studies to date are empirical studies that have focused on the strategic renewal’s antecedents, while the strategic renewal’s outcomes remain unexplored. This and other significant research gaps are identified and discussed in this review, which emphasizes the need for further research about the topic.El objetivo del presente trabajo es examinar el estado actual de la investigación sobre renovación estratégica y empresa familiar con el fin de identificar los principales gaps de investigación y proporcionar un camino a los académicos para futuras investigaciones. Para ello hemos realizado una revisión comprensiva y sistemática de 21 trabajos (20 artículos y 1 capítulo de libro) publicados entre 2009 y 2022. Entre los diferentes hallazgos y teniendo en cuenta que la mayoría de nuestros trabajos revisados son empíricos, la mayoría de la investigación cuantitativa es de carácter transversal y la variable renovación estratégica es adoptada en todos los trabajos como variable dependiente

Optimization of the diffraction efficiency in photorefractive crystals

The aim of this work is to study and to optimize the diffraction efficiency in sillenite BTO crystals. A theoretical analysis, where the effects of coupling beams are significant,is carried on. In addition, non-mobile transmission gratings are considered. The diffraction efficiency is obtained by using the coupled wave equations in on-Bragg regime using Method Runge-Kutta of order 4 in Matlab. Also, the non-uniformity of the gratings in side the crystal sample, the optical activity of the material and the polarization of the recording beams are taken into account.Fil: Villamizar Amado, Astrid Lorena. Universidad de Pamplona; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arias Hernández, Néstor Alonso. Universidad de Pamplona; ColombiaFil: Molina Prado, Martha Lucia. Universidad de Pamplona; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tebaldi, Myriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Ópticas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones Ópticas. Universidad Nacional de La Plata. Centro de Investigaciones Ópticas; Argentin