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L’effetto della temperatura della camera di stampa sulle tensioni residue sui componenti stampati FDM
No full textThermographical analysis of friction stir welding and laser assisted friction stir welding
No full textFriction Stir Welding (FSW), developed at The Welding Institute (TWI) in 1991, is a new solid-state welding process. In this technique, the material does not reach the fusion but the joint is the consequence of the plasticization resulting from the generation of heat by friction and the stirring action of the pin on the material due to the rotation and the displacement of a non-consumable tool. Thus, the FSW reaches temperatures lower than those reached by conventional fusion welds. Laser Assisted Friction Stir Welding (LAFSW) is a combined welding technique in which the FSW is assisted, during the weld, by the pre-heating of a de-focalized laser. This technique leads higher welding speeds, lower clamping force and it has some benefits for tool wear. Nevertheless the control of the temperature field is fundamental to guarantee a high quality joint. In this work FSW and LAFSW bead on plate tests were conducted on 6 mm thick 5754H111 aluminium alloy plates with constant tool rotation and welding speed. Thermographic images were acquired to compare the effect on the temperature field of laser source distance from the tool and laser powe
Money back guarantee? A cost–benefit framework of performance-based agreements (PBAs) for the reimbursement of pharmaceuticals
No full textThe aim of this paper is to provide an empirical framework based on a
discrete-time Markov chain to assess the costs and benefts of Performance Based
Agreements (PBAs) for the reimbursement of pharmaceuticals. We provide an
empirical testing using a case study referring to a treatment recently approved for
reimbursement in Italy. The implementation of this framework is challenging for the
agencies dealing with pricing and reimbursement decisions given the uncertainty
associated with the treatment efectiveness and safety. On the other hand, empirical
evidence shows that the awareness of the expected costs associated with diferent
reimbursement schemes is necessary to inform decision-makers
The role of peening processes as a pre-treatment to anodizing on fatigue behavior of aircraft aluminum alloy
Full text linkIn this work, the possibility of employing shot peening and laser peening as pre-treatments to a tartaric-sulfuric anodizing process on the fatigue behavior of 7050-T7451 aluminum alloy components was investigated. The surface modifications and stress fields induced by the combination of the peening and anodizing processes were evaluated by scanning electron microscopy and residual stress assessment methodologies based on diffraction techniques, respectively. It was found that the anodizing process alone results in a significant reduction in fatigue life compared to the as-machined condition especially in the high-cycle fatigue (HCF) region of the S-N diagrams due to the presence of defects within the anodic layer that act as stress concentrators facilitating the initiation of fatigue cracks. The application of both shot and laser peening treatments is demonstrated to offset the negative effects induced by anodizing, offering greater safety margins useful for the design of critical aeronautical structures.The possibility to employ peening processes as pre-treatments to anodizing was studied.No significant influence of anodizing on residual surface stresses was observed.SP and LP provide significant benefits in the fatigue behavior of anodized components.Thicker anodic layers result in greater susceptibility to fatigue crack nucleation
Residual stress measurement on Titanium Grade 5 and Inconel 625 thin dissimilar welded joints by contour method
No full textResidual stress assessment is a key factor in engineering design owing to its impact on engineering properties of materials, structural components and welded joints. In dissimilar welding, residual stresses arise due to both the welding process itself and the different coefficients of thermal expansion of the two welded materials. The longitudinal residual stresses in 2-mm-thick laser-welded Ti–6Al–4V and Inconel 625 plates with two intermediate inserts of Vanadium and steel were determined using the contour method and the X-ray diffraction. For all the specimens analyzed, the contour method stress maps revealed that the highest tensile residual stress zone occurred in the steel insert, while compression was found in the base metals. Moreover, harmful surface tensile stresses arose at the welds between steel and Vanadium. Lastly, among the three welding schemes examined, the dissimilar joint realized with the AISI 316L insert exhibited the lowest harmful surface tensile residual stresses
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
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