1,720,993 research outputs found
Preparation and characterization of poly (butylene terephthalate) / graphene composites by in-situ polymerization of cyclic butylene terephthalate
No full textRecently, cyclic butylene terephthalate (CBT) oligomers stimulated a great interest because of their waterlike viscosity and ability to be readily polymerized to form the engineering thermoplastic poly(butylene terephthalate) (PBT)1 ; their ultra-low viscosity makes them well suited for numerous processes, such as composite processing. CBT in-situ polymerization in the presence of graphene should then provide an ideal solution for the preparation of homogeneously dispersed PBT/graphene composites. The possibility to industrialize the production of graphene-filled engineering polymers paves the way to applications in electronic devices and communication instruments for commercial, military and scientific purposes.2 Many other applications in the automotive and aerospace sector, requiring sufficient conductivity to provide electrostatic discharge, have been considered so far as ideal uses for nanotubes reinforced composites and could be interested by PBT with graphene
Book review, Animali da compagnia: tutele – diritti – responsabilità, Elena Bassoli (a cura di)
No full textL'avvocato, docente universitario e presidente dell'Associazione Nazionale Giuristi Informatici e Forensi, Elena Bassoli, ha curato un manuale che affronta le problematiche relative ai diritti degli animali, approfondendo prima la legislazione internazionale e poi le singole pieghe di quella italiana. Il dato da cui si parte sembra secondario ma, invero, è assai rilevante, ovvero che nel nostro Paese si è passati molto lentamente da una concezione esclusivamente utilitaristica degli animali (tutelati in quanto proprietà di qualcuno) all'affermazione dei diritti propri dell'animale in quanto tale.Animali da compagnia: tutele – diritti – responsabilità è utile soprattutto alla luce dei Trattati internazionali (D.U.D.A., Trattato di Amsterdam, Trattato di Lisbona) che nel corso degli anni hanno introdotto la tutela dell'animale nelle legislazioni di tutto il mondo. La curatrice e i collaboratori hanno analizzato la recente giurisprudenza sugli animali da compagnia e le varie fonti del diritto nazionale, europeo e internazionale, passando in rassegna le norme di riferimento e indicandone l'applicabilità e le procedure con il fine dichiarato di: "Offrire al lettore uno strumento utile, rigoroso e scritto in modo chiaro e comprensibile anche per chi, per la prima volta, si trovi ad affrontare questa parte del diritto". Il manuale si presenta precipuamente come uno strumento di lavoro per i professionisti che trattano le problematiche relative al mondo degli animali domestici. Va segnalata, in proposito, la chiarezza non solo nell'esposizione dei concetti ma anche nell'architettura editoriale. I 10 capitoli che lo compongono forniscono un inquadramento sistematico delle implicazioni amministrative e penali, con rimandi a diverse note per una maggiore chiarezza del testo: dalle origini del diritto animale (dall'antica Grecia all'animalismo contemporaneo, con in mezzo Medioevo, Rinascimento e Darwinismo) passando alla tutela degli animali nell'ordinamento legislativo internazionale, al rapporto tra condomini, al maltrattamento sugli animali, al problema del randagismo, alla responsabilità per il danno cagionato dagli animali e per il danno da morte dell'animale domestico, fino alle responsabilità del medico veterinario
Joining mechanisms and mechanical properties of PA composites obtained by Selective Laser Sintering
Full text linkPURPOSEAdditive Manufacturing is today a viable industrial solution besides traditional processes. Techniques like Selective Laser Sintering address the issues of digital production and mass customization in a variety of materials. Composite parts can be obtained with specific functional and mechanical properties. Building orientation during Additive Manufacturing often causes anisotropy of parts’ properties that is still unspecified in technical information. The paper investigates the mechanical performances and failure mechanisms of an Aluminium-filled polyamide and of a new Alumina-polyamide composite produced by SLS, in comparison with unfilled PA.DESIGN/METHODOLOGY/APPROACHA specific focus is set on the evaluation of primary and secondary anisotropy in the case of metal or ceramic filler, as well as on the specific contribution of powder distribution modes and joining phenomena. Macroscopic mechanical tests and the observation of joining and failure micro-mechanisms are integrated.FINDINGSThe results prove the absence of relevant anisotropy amongst specimens that are produced with the axis parallel to the plane of powder deposition. Samples whose axis is parallel to the growth direction Z, instead, reveal a significantly different response with respect to other orientations.ORIGINALITY/VALUEAn original explanatory model is assumed and validated, based on an anisotropic distribution of the reinforcing particles during parts’ production, which determines the efficacy of the strengthening mechanisms during crack propagation
Micro-CT of 3D vascular structures: clues for innovative scaffolds in organ engineering
No full textOrgan transplantation is the only definitive treatment for patients with incurable
diseases of soft and hard tissue structures, including parenchyma and bones.
However, shortage and aging of cadaveric and alive donors, and a number of other
ethical and clinical issues render complex any organ transplant1. A recent hope has
been raised by regenerative medicine and tissue engineering, but current
methodologies are yet limited to the reconstruction of either tissue fragments or
implantation of biocompatible scaffolds to be colonized by the regenerating areas.
Although recent advancement in material science and stem cell biology has led to
biocompatible scaffolds more efficient than in the past, still these constructs are
designed without any anatomy of the vasculature intrinsic to the recipient organ,
based on the assumption that nutrients and oxygen are supplied by diffusion from
adjacent tissues2. Since in both parenchyma and bones the tissue mass grows
around a complex vascular tree, we have recently developed an innovative
bioengineering approach to reconstruct on the laboratory bench an entire bioartificial
organ with a pre-formed internal vascular network acting as a natural scaffold for
seeded stem cells, and as a guide for colonizing vessels, possibly improving the
functional and transplantation performance of the bioconstruct 3. Micro-CT play a key
role to obtain visual and numerical information on the complex vascular geometry of
the organ to be engineered. We here present data on vascular casts of the rat lungs,
and human kidney and thyroid gland, to be used in the development of STL-
algorithms for CAD-based, inverse engineering of biomaterial replicas of soft tissue organ vasculature
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
