Carbon fiber reinforced polymers: matrix modifications and reuse of carbon fibers recovered by pyrolysis

Due to their extraordinary properties, Carbon Fiber Reinforced Polymers (CFRPs) are used in a growing number of fields (automotive, military, aircraft, aerospace, wind turbines, sport, civil infrastructure and leisure). Since the matrix in CFRPs is polymer-based, these composites have poor resistance to fire; additionally, when exposed to high temperatures, they can burn or lose their thermo-mechanical stability. Moreover, the recent huge and continuous development of CFRPs opened the question related to their disposal and total dependence on fossil resources. This thesis focussed on epoxy-based CFRPs. In more detail, commercial epoxy resins have been modified and replaced with bio-based alternatives, and short recycled carbon fibers composites have been produced. Two new bentonite-based organoclays were prepared with low cost reactants and mild reactions conditions and used to modify the flame behaviour of a commercial epoxy resin. The epoxy-modified resin flame behaviour was evaluated by cone-calorimeter and some significant improvements with just a 3 %wt loading level of organoclay were obtained. Furthermore, the possibility to recover and reuse carbon fibers by pyrolysis of CFRPs waste was studied: a validation of the recycling conditions and the treatments required to reuse recycled carbon fibers were assessed in order to obtain clean fibers and promote fiber/matrix adhesion in epoxy composites. Recycled carbon fiber were then used in a lab-scale composite manufacturing process and comparable mechanical properties for virgin and recycled short carbon fiber composites were achieved when an optimized coupled pyrolysis/oxidative process to CFRPs waste is applied. Finally, more sustainable CFRPs have been produced and characterized coupling highly bio-based epoxy systems, appropriately modified and optimized, and recycled carbon fibers. This latter work represents the first attempt aimed at replacing petroleum- BPA-based epoxy resins and high cost short virgin carbon fibers in the future CFRPs manufacturing processes

On the Decentralization of Health Systems for Data Availability: a DLT-based Architecture

Mobile devices entered people's lives by leaps and bounds, offering various applications relying on private third-party entities to manage their users' data. Centralized control of personal health data endangers the privacy of the users directly involved. In the future, there will likely be a trend toward decentralizing the health data collection, relieving central entities of this task. This comes with several challenges in a decentralized environment, such as avoiding a single point of failure to guarantee data availability. The following work proposes an architecture based on Distributed Ledger Technology to allow users to decide on their data while ensuring availability by employing social networks. We will outline the mechanisms behind data storage and the implications of using smart contracts in the architecture. In concluding the work, we show the developed architecture and results deriving from its assessment, highlighting possible use cases applied to the specific health data management context

Bifurcation bias and exporting: Can foreign work experience be an answer? Insight from European family SMEs

We develop hypotheses from a “bifurcation bias” approach involving the asymmetric treatment of family and nonfamily assets, and we test them on a sample of 6893 European family SMEs. Our findings reveal two asymmetries relating to actions designed to reduce bifurcation bias. First, exporting is indeed positively associated with the presence of outside owners and managers, and from the interaction between them. However, this interaction replaces any separate positive impact from outside ownership. Second, the international work experience of managers has a positive impact on exporting, but this experience seems relevant only in the case of firms with family-managers only

Castleman's disease in childhood: report of three cases and review of the literature

Castleman's disease (CD) is a rare, localized or generalized, lymphoproliferative disorder with a frequent mediastinal location, but possible in any lymph node or extra nodal site. It usually appears in young adults whilst it rarely occurs in childhood. There are only about 100 pediatric cases published, five of them in Italy. We report 3 cases of localized Castleman's disease, investigated in our Department in a 3 years period and reviewed the literature

Aspetti epidemiologici della calcolosi di calcio in Italia: distribuzione dei fenotipi intermedi nella popolazione italiana

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The Signal Processing Firmware for the Low Frequency Aperture Array

The signal processing firmware that has been developed for the Low Frequency Aperture Array component of the Square Kilometre Array is described. The firmware is implemented on a dual FPGA board, that is capable of processing the streams from 16 dual polarization antennas. Data processing includes channelization of the sampled data for each antenna, correction for instrumental response and for geometric delays and formation of one or more beams by combining the aligned streams. The channelizer uses an oversampling polyphase filterbank architecture, allowing a frequency continuous processing of the input signal without discontinuities between spectral channels. Each board processes the streams from 16 antennas, as part of larger beamforming system, linked by standard Ethernet interconnections. There are envisaged to be 8192 of these signal processing platforms in the first phase of the Square Kilometre array so particular attention has been devoted to ensure the design is low cost and low power

The Digital Signal Processing Platform for the Low Frequency Aperture Array: Preliminary Results on the Data Acquisition Unit

A signal processing hardware platform has been developed for the Low Frequency Aperture Array component of the Square Kilometre Array (SKA). The processing board, called an Analog Digital Unit (ADU), is able to acquire and digitize broadband (up to 500MHz bandwidth) radio-frequency streams from 16 dual polarized antennas, channel the data streams and then combine them flexibly as part of a larger beamforming system. It is envisaged that there will be more than 8000 of these signal processing platforms in the first phase of the SKA, so particular attention has been devoted to ensure the design is low-cost and low-power. This paper describes the main features of the data acquisition unit of such a platform and presents preliminary results characterizing its performance

Gamma-Ray Burst observations by the high-energy charged particle detector on board the CSES-01 satellite between 2019 and 2021

In this paper we report the detection of five strong Gamma-Ray Bursts (GRBs) by the High-Energy Particle Detector (HEPD-01) mounted on board the China Seismo-Electromagnetic Satellite (CSES-01), operational since 2018 on a Sun-synchronous polar orbit at a $\sim$ 507 km altitude and 97$^\circ$ inclination. HEPD-01 was designed to detect high-energy electrons in the energy range 3 - 100 MeV, protons in the range 30 - 300 MeV, and light nuclei in the range 30 - 300 MeV/n. Nonetheless, Monte Carlo simulations have shown HEPD-01 is sensitive to gamma-ray photons in the energy range 300 keV - 50 MeV, even if with a moderate effective area above $\sim$ 5 MeV. A dedicated time correlation analysis between GRBs reported in literature and signals from a set of HEPD-01 trigger configuration masks has confirmed the anticipated detector sensitivity to high-energy photons. A comparison between the simultaneous time profiles of HEPD-01 electron fluxes and photons from GRB190114C, GRB190305A, GRB190928A, GRB200826B and GRB211211A has shown a remarkable similarity, in spite of the different energy ranges. The high-energy response, with peak sensitivity at about 2 MeV, and moderate effective area of the detector in the actual flight configuration explain why these five GRBs, characterised by a fluence above $\sim$ 3 $\times$ 10$^{-5}$ erg cm$^{-2}$ in the energy interval 300 keV - 50 MeV, have been detected.Comment: Accepted for publication in The Astrophysical Journal (ApJ

A comprehensive analysis of filamentous phage display vectors for cytoplasmic proteins: an analysis with different fluorescent proteins

Filamentous phage display has been extensively used to select proteins with binding properties of specific interest. Although many different display platforms using filamentous phage have been described, no comprehensive comparison of their abilities to display similar proteins has been conducted. This is particularly important for the display of cytoplasmic proteins, which are often poorly displayed with standard filamentous phage vectors. In this article, we have analyzed the ability of filamentous phage to display a stable form of green fluorescent protein and modified variants in nine different display vectors, a number of which have been previously proposed as being suitable for cytoplasmic protein display. Correct folding and display were assessed by phagemid particle fluorescence, and with anti-GFP antibodies. The poor correlation between phagemid particle fluorescence and recognition of GFP by antibodies, indicates that proteins may fold correctly without being accessible for display. The best vector used a twin arginine transporter leader to transport the displayed protein to the periplasm, and a coil-coil arrangement to link the displayed protein to g3p. This vector was able to display less robust forms of GFP, including ones with inserted epitopes, as well as fluorescent proteins of the Azami green series. It was also functional in mock selection experiments

Notas sobre a Carta de Veneza

This paper presents a critical reading of the Venice Charter, an Icomos key document, fruit of a conference held in 1964. The Charter is often quoted in Brazil but is not always properly understood. The conservation and restoration charters - especially those produced by international institutions - are documents that have an indicatory or, at the most, prescriptive character. They constitute the deontological foundation of many professionals involved in preservation, but they are not recipes for immediate use. In order to elaborate a well-founded reading of the document, its ideas must be understood in connection to the theoretical postulates of the time they were engendered and to the developments of the field. Thus this paper will examine these subjects, commenting and enlightening the Charter's articles and pointing out the origins of specific ideas. It also discusses how the Charter relates to previous documents and their theoretical foundations. This approach, based in a critical analysis, is necessary in order to reach a fuller interpretation of the Charter's indications so that they can be used in the present