The ANTARES Optical Module

The ANTARES collaboration is building a deep sea neutrino telescope in the Mediterranean Sea. This detector will cover a sensitive area of typically 0.1 km-squared and will be equipped with about 1000 optical modules. Each of these optical modules consists of a large area photomultiplier and its associated electronics housed in a pressure resistant glass sphere. The design of the ANTARES optical module, which is a key element of the detector, has been finalized following extensive R & D studies and is reviewed here in detail.Comment: 26 pages, 15 figures, to be published in NI

ANTARES: the first undersea neutrino telescope

The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Una experiencia de reforma curricular:: El Plan de estudios de Derecho de la Universidad Diego Portales

The Law School of the Diego Portales University was founded in 1982, receiving their first group of students next year. She was created under the education law of 1981, which permitted the creation of new universities, others than the traditional ones, like the public and confessional universities.La escuela de Derecho de la Universidad Diego Portales fue fundada en 1982, recibiendo a su primer contingente de alumnos el año siguiente. Fue creada al amparo del DFL 1, de 1981, Ley Orgánica Constitucional de Educación, que permitió la creación de nuevas universidades, distintas de las tradicionales existentes, esto es, universidades estatales y de la Iglesia

An xfem-based numerical scheme to compute crack-induced electrical resistivity changes in cracked cnt-reinforced composites using ansys

Volumen 2309 Número Artículo 0033981This paper presents an eXtended Finite Element Method (XFEM)-based numerical scheme to compute electrical resistivity changes caused by the presence of cracks. Using the commercial finite element package ANSYS, the virtual continuous monitoring of the structure is solved in two steps. First, the strain response of the cracked composite domain is computed by means of the XFEM. In the second step, the electrical conductivity of the piezorresistive elements located in the domain are updated according to the strain state and the electric resistance between two electrodes of the damaged plate is computed. The comparison with the electric resistance measured for the undamaged plate allows us to detect the presence of a crack and its severity. Several numerical studies are provided to show the capabilities of this computational framework.Consejería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía P18-RT-3128Junta de Andalucía EJ3-77Ministerio de Economía y Competitividad DPI2017-89162-

Design of lead-free PVDF/CNT/BaTiO3 piezocomposites for sensing and energy harvesting: The role of polycrystallinity, nanoadditives, and anisotropy

Lead-free piezoelectric composites with polymeric matrices offer a scalable and eco-friendly solution to sensing and energy harvesting applications. Piezoelectric polymers such as PVDF are particularly interesting because of the possibility to engineer the performance of these materials through addition of higher-performance piezoelectric inclusions and nanomaterials and to scalably manufacture such composites by emerging techniques such as 3D printing. This work makes two contributions, namely towards composite design and towards development of accurate effective property models. In the context of composite design, we evaluate the piezoelectric performance of PVDF modified by the addition of polycrystalline-BaTiO3 and multiwalled carbon nanotubes. Firstly, the addition of BaTiO3 dramatically improves the electric field within the composite offering significant advantages specially at low BaTiO3 concentrations. Secondly, the addition of carbon nanotubes to the matrix, particularly at higher BaTiO3 loadings, leads to an order of magnitude increase in the piezoelectric flux generation. Further enhancement in the flux generation is also possible by tuning the polycrystallinity of the BaTiO3 inclusions. However, these behaviours are inclusion-driven and the piezoelectric behaviour of the matrix does not contribute to this improvement. Importantly, a small addition of BaTiO3 and CNT into the PVDF matrix, away from percolation, can simultaneously improve flux and electric field generation. In this part of the work, we assume an isotropic PVDF matrix. Given that PVDF is elastically anisotropic, the second aspect of this work is the development of an effective property model for CNT-modified PVDF, taking into account the elastic anisotropy of poled PVDF, to predict the elastic coefficients of CNT-modified PVDF matrices, thus undertaking a key step towards modelling anisotropic piezoelectric composites. We show that the anisotropy-based model makes similar predictions in the effective composite behaviour, indicating that in the case of PVDF-based piezocomposites, the anisotropy of the matrix does not significantly affect the piezoresponse

Lead-free piezocomposites with CNT-modified matrices: Accounting for agglomerations and molecular defects

Piezoelectric matrix-inclusion composites based on lead-free ceramics have attracted attention due to the possibility of manufacturing environmentally friendly devices using scalable emerging technologies such as 3D printing. However, lead-free materials lag lead-based piezo-composites in terms of performance, thus necessitating new design strategies to escalate piezoelectric response. Here, we build a modeling paradigm for improving the piezoelectric performance through improved matrices and optimal polycrystallinity in the piezoelectric inclusions. By incorporating carbon nanotubes in the matrix, we demonstrate 2–3 orders of improvement in the piezoelectric response, through simultaneous hardening of the matrix and improvement in its permittivity. By tuning the polycrystallinity of the piezoelectric inclusions, we show considerable improvements exceeding 50% in the piezo-response, compared to single crystal inclusions. We further analyze the influence of carbon nanotube agglomerations at supramolecular length scales, as well as vacancy defects in the nanotubes at the atomic level, on composite performance. Although nanomaterial agglomeration is conventionally considered undesirable, we show that, near nanotube percolation, clustering of nanotubes can lead to better matrix hardening and higher permittivities, leading to improvements exceeding 30% in the piezoelectric response compared to non-agglomerated architectures. We further demonstrate that although atomic vacancy defects in nanotubes effectively soften the matrix, this can be compensated by agglomeration of nanotubes at larger length-scales