An analytical model for high velocity impacts on thin CFRPs woven laminated plates

15 pages, 12 figures.-- MSC2000 codes: Primary: 74R15; Secondary: 74M20, 74E30, 74K20, 74-05.Zbl#: Zbl 1178.74147An analytical model to study the impact process of a spherical projectile penetrating at high velocity into a carbon/epoxy plain woven laminate is developed in this work. The model is based on an energy balance, where the kinetic energy of the projectile is absorbed by the laminate by three different mechanisms: laminate crushing, linear momentum transfer and tensile fiber failure. A non-homogeneous differential equation is obtained. A subsequent simplification using regular perturbation analysis gives a closed-form solution that allows the approximative calculation of the residual velocity and hence the ballistic limit. The model is validated with the results of experimental tests in which the residual velocity is measured by means of high speed cameras.The authors are indebted to the Comisión Interministerial de Ciencia y Tecnología of Spain for the financial support of this work (Project MAT98-0273).Publicad

The effect of low temperatures on the intermediate and high velocity impact response of CFRPs

8 pages, 13 figures.The influence of low temperature on the damage produced on CFRPs by intermediate and high velocity impacts is analyzed. Spherical projectiles were launched against different carbon fiber/epoxy laminates (tape and woven). Experimental tests were done at temperatures ranging from 25 to −150 °C. The extension of the damage was measured by C-Scan. Results show a clear dependence of damage on temperature, impact velocity and the type of the laminate.The authors are indebted to the Comisión Interministerial de Ciencia y Tecnología of Spain for financial support of this work (Project MAT98-0273). They also thank EADSCASA for assistance in C-Scan measurements.Publicad

Experimental and numerical analysis of normal and oblique ballistic impacts on thin carbon/epoxy woven laminates

14 pages, 17 figures.A finite element numerical model for carbon/epoxy woven laminates has been used to predict residual velocity and damaged area when subjected to high impact velocities. Experiments using a gas gun were conducted to investigate the impact process and to validate the model, measuring the two variables previously indicated. A morphology analysis was also made to investigate the different breakage mechanisms that appear during the penetration process. The influence of the impact velocity and obliquity has been studied using the numerical tool, in a wide range of impact velocities and considering two impact angles, 0° and 45°.The authors are indebted to the Comisión Interministerial de Ciencia y Tecnología of Spain for the financial support of this work (Project MAT98-0273).Publicad

High energy impact on woven laminates

6 pages, 5 figures.-- Issue title: "EURODYMAT 2003 - 7th International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading" (Porto, Portugal, Sep 8-10, 2003).The influence of high velocity impacts on CFRPs was studied by launching Spherical steel masses, at velocities from 60 m/s to 550 m/s, against carbon fiber/epoxy woven laminates. The extension of the damage induced in the laminate was measured by C-Scan. Finite element numerical simulation of the impact test used a failure model based on the Chang-Chang model. A comparison was made of the damaged areas resulting from non-destructive inspection of the specimens and those predicted by numerical simulation. To conclue the analysis, an analytical model developed by Cantwell-Morton was used to calculate the residual velocity of the projectile after perforation. The residual velocities predicted by numerical and by analytical models, were also compared.The authors are indebted to the Comisión Interministerial de Ciencia y Tecnologia of Spain for financial support of this work (Project MAT98-0273). They also thank EADS-CASA for assistance in C-Scan measurements.Publicad

Sociotipo y políticas asistenciales: Un nuevo instrumento de evaluación de las intervenciones biomédicas y de sociabilización

La presente Tesis pretende aproximarse a las políticas públicas desde un nuevo ángulo: el de la sociabilidad. Está basada en un concepto novedoso, el “sociotipo”, que ha sido acuñado en la investigación del grupo de Bioinformación del Instituto Aragonés de Ciencias de la Salud (IACS) al que esta autora pertenece. Como vamos a argumentar a lo largo de esta Tesis, un análisis en profundidad y una reorientación de las políticas asistenciales resultan apremiantes en la época actual. Desde el estudio teórico y empírico del sociotipo pretendemos contribuir a este debate de interés público. En concreto, se van a abordar las prácticas asistenciales de dos ámbitos: el propiamente socio-asistencial y el de la sanidad. Como veremos, el sociotipo proporciona una nueva perspectiva desde la que se hacen más evidentes determinadas carencias del conjunto de nuestro sistema asistencial.<br /

Influence of hand tracking in immersive virtual reality for memory assessment

Few works analyze the parameters inherent to immersive virtual reality (IVR) in applications for memory evaluation. Specifically, hand tracking adds to the immersion of the system, placing the user in the first person with full awareness of the position of their hands. Thus, this work addresses the influence of hand tracking in memory assessment with IVR systems. For this, an application based on activities of daily living was developed, where the user must remember the location of the elements. The data collected by the application are the accuracy of the answers and the response time; the participants are 20 healthy subjects who pass the MoCA test with an age range between 18 to 60 years of age; the application was evaluated with classic controllers and with the hand tracking of the Oculus Quest 2. After the experimentation, the participants carried out presence (PQ), usability (UMUX), and satisfaction (USEQ) tests. The results indicate no difference with statistical significance between both experiments; controller experiments have 7.08% higher accuracy and 0.27 ys. faster response time. Contrary to expectations, presence was 1.3% lower for hand tracking, and usability (0.18%) and satisfaction (1.43%) had similar results. The findings indicate no evidence to determine better conditions in the evaluation of memory in this case of IVR with hand tracking

Genetic algorithm optimization of entanglement

We present an application of a genetic algorithmic computational method to the optimization of the concurrence measure of entanglement for the cases of one dimensional chains, as well as square and triangular lattices in a simple tight-binding approach in which the hopping of electrons is much stronger than the phonon dissipationComment: 26 pages with 13 figures, based on Chapter 3 of the Master thesis of the first author defended at IPICyT, San Luis Potosi, Mx, on 22nd of February 2006, similar to the published version [Fig. 5 left out but contains the Appendix figure

Communicative frames in the online strategy of European political parties during the coronavirus crisis: a polyhedral look at the far right

The current debate in the academic sphere regarding the role of extreme right-wing parties during the coronavirus pandemic extends to its communicative aspect. While some authors argue that these parties have focused their messages on the perspectives of fear, the threat represented by immigrants, or conspiracies in an unsuccessful way, even considering them to be the “losers of the crisis,” others emphasize their ability to build a sense of community through resilience. The present research aims to take up these discussions and delve deeper into the study of the communicative frames of European political parties, with a particular focus on the far right, to draw more nuanced conclusions. For this purpose, a double methodology has been implemented through the coding of the frames used in a total of 2,757 Twitter posts during the month of March 2020 from the major government and extreme right-wing parties in Germany, France, Spain, and Poland. The results show that the parties studied present differences in their communicative frames, not according to their position on the ideological spectrum, as might be expected, but rather to their role as the executive power in the government or as part of the opposition of their respective legislative chambers

El uxoricidio por adulterio en el Reino de Aragón durante el siglo XV: un acercamiento a través de las fuente documentales de la época.

El uxoricidio en caso de adulterio durante la Edad Media fue una de las manifestaciones de violencia conyugal de las que más y mejor constancia se tiene si nos ceñimos a las fuentes documentales del período. Además, el propio adulterio constituyó una de las infracciones que con mayor frecuencia llevó a las mujeres ante los tribunales de justicia. Para comprender el funcionamiento de este «proceso relacional» es necesario remontarnos al Derecho Romano ―perteneciente a los últimos siglos de la Antigüedad―, dado que sentó las bases de los códigos legislativos posteriores y marcó la pauta de fijación del derecho consuetudinario hispánico.Durante los siglos alto y plenomedievales se llevó a término una evolución legislativa con dos fases bien diferenciadas ―la de «dispersión normativa» y la de recepción del derecho romano-canónico―, que desembocó en el establecimiento del «derecho general» y la disminución de la permisividad con los maridos que asesinaban a sus esposas adúlteras, aunque no se haría efectiva hasta el siglo XIII. En el caso del Reino de Aragón, el impacto de este fenómeno y las penas asociadas al adulterio estuvieron más mitigadas que en el resto de la península, aunque sin dejar de lado la degradación del estatuto jurídico y social de la mujer en los siglos bajomedievales. En este sentido, la documentación aragonesa es rica en procesos relacionados con situaciones delictivas derivadas del adulterio, especialmente vinculadas a la actuación femenina como anticipación ante una posible explosión de violencia ―jurídicamente legitimada― por parte del marido engañado.<br /