3,476 research outputs found
Evaluation of additive manufacturing (AM) techniques for the production of metal-ceramic dental restorations
No full textTwo approaches, based on time compression techniques, have recently been introduced for the production of dental restorations: the use of drop-on-demand (DoD) wax patterns for the investment casting of cobalt-chromium (CoCr) alloy and the direct fabrication of metal restorations by means of selective laser sintering additive technique. These two technologies are analysed in this paper from the point of view of the accuracy of the final product that can be achieved. To this aim, the Virtual Model (VM) of a specifically designed artefact for dental applications has been used as a reference model. The restorations were first designed, disregarding the manufacturing process, in order to have a single geometry for the subsequent comparisons and were then produced in dental laboratories on the basis of the given geometry. After fabrication, the restoration surfaces were inspected, by using a coordinate measuring machine (CMM), to obtain information on the achieved accuracy. The results have shown that both processes are able to produce clinically acceptable restoration
Economics of additive manufacturing for end-usable metal parts
No full textAdditive manufacturing (AM) of metal parts combined with part redesign has a positive repercussion on cost saving. In fact, a remarkable cost reduction can be obtained if the component shape is modified to exploit AM potentialities. This paper deals with the evaluation of the production volume for which AM techniques result competitive with respect to conventional processes for the production of end-usable metal parts. For this purpose, a comparison between two different technologies for metal part fabrication, the traditional high-pressure die-casting and the direct metal laser sintering additive technique, is done with consideration of both the geometric possibilities of AM and the economic point of view. A design for additive manufacturing approach is adopted. Costs models of both processes are identified and then applied to an aeronautical component selected as case study. This research evidences that currently additive techniques can be economically convenient and competitive to traditional processes for small to medium batch production of metal part
Study on unsupported overhangs of AlSi10Mg parts processed by Direct Metal Laser Sintering (DMLS)
No full textA well-known limitation of powder bed additive manufacturing techniques for metals is the requirement of support structures on down-facing surfaces. The aim of this research is addressed to the evaluation of geometrical parameters of self-supporting faces and estimation of the achievable tolerance of surfaces built without requiring a support structure. In order to accomplish the purpose of this study a Design of Experiment (DoE) approach is adopted to explore the significance of key parameters such as angle, curvature and slenderness of overhanging surfaces. Deviation between the actual and the nominal CAD geometries is computed, and results are processed following the tolerance unit method defined in international standards (IT grade). At the end of this study, the closest tolerance obtainable on self-supporting faces and related geometrical parameters are identified, limited to Direct Metal Laser Sintering (DMLS) of aluminium parts. © 2015 The Society of Manufacturing Engineer
A imagem de Alessandro Baricco no Brasil
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Estudos da Tradução, Florianópolis, 2013.Com a intenção de delinear o modo pelo qual o escritor italiano Alessandro Baricco se inseriu no sistema literário brasileiro e os caminhos percorridos pelos seus livros traduzidos, esta dissertação dá voz às experiências tradutórias de seus tradutores. A inserção de Bariccono Brasil tem seu início em 1997, através de uma proposição da Profa. Dra. Roberta Barni à editora Iluminuras da tradução de Oceano Mare. A partir daí, outras sete obras foram publicadas no Brasil, sendo três delas traduzidas por Roberta Barni e as outras quatro por quatro tradutores diferentes. De um lado, considera-se o tradutor como figura principal namediação entre culturas, e, de outro, se analisa a realidade desta figuradentro do sistema literário, sua invisibilidade, seus limites e o exercíciode sua profissão. A pesquisa conta, ainda, com críticas e resenhas referentes ao autor italiano publicadas em jornais consagrados no Brasil, considerando estas como parte constituinte da imagem de Baricco refletida em território nacional. Abstract : Intending to delineate the way the Italian writer Alessandro Baricco has been inserted in the Brazilian literary system and the paths his translated books have followed, this thesis gives voice to the translating experiences of his translators. Baricco's insertion in Brazil began in 1997, through a personal project of Dr. Roberta Barni, with her translation of Oceano Mare. Since then, seven other of his works have been published in Brazil, three of which were translated by Roberta Barni and the other four by four different translators. On the one hand,the translator is considered as the main figure in mediation betweencultures and, on the other, this figure's reality is analyzed within theliterary system: its invisibility, its limits and its professional practice. Criticisms and reviews of this Italian author published in well established Brazilian newspapers are also considered, with the understanding that they are part of Baricco's image reflected here
Il lessico delle emozioni nelle traduzioni dei salmi nelle lingue germaniche antiche
No full textI Salmi sono certamente uno dei libri della Bibbia più popolari nelle comunità monastiche altomedievali. Venivano imparati a memoria per essere cantati durante la liturgia. Di conseguenza, le loro traduzioni germaniche non rispondevano principalmente alla necessità di comprendere il testo latino, che era già stato assimilato, ma erano piuttosto strumenti per aiutare la meditazione del contenuto spirituale del salmo. In questa prospettiva, le parole delle emozioni si rivelano un campo d'indagine privilegiato per comprendere il rapporto che il traduttore aveva con l'ipotesto e la versatilità delle lingue germaniche nel rappresentare le emozioni fondamentali contenute nei salmi: rabbia, paura e gioia. Il corpus d'indagine copre l'inglese antico, il basso tedesco, l'antico sassone e l'antico alto tedesco. Infine, l'analisi comparativa del lessico permette di cogliere quanto fossero strette le relazioni tra le lingue germaniche continentali per quanto riguarda le traduzioni dei salmi, mentre le versioni in inglese antico si dimostrano isolate, optando in molti casi per scelte lessicali specifiche.The Psalms are certainly one of the most popular books of the Bible in the monastic communities of the early Middle Ages. They were learnt by heart to be sung during the liturgy. Consequently, their Germanic translations did not primarly repsond to the need for comprehension of the Latin text, which had already been assimilated, but rather were tools to aid meditation on the spiritual content of the psalm. Within this perspective, the words for emotions prove to be a privileged field of investigation to understand the relationship that the translator had with the hypotext and the versatility of the Germanic languages in representing the fundamental emotions contained in the psalms: anger, fear, and joy. The survey corpus covers Old English, Low German, Old Saxon, and Old High German. Finally, the comparative analysis of the lexicon allows us to grasp how close the relationchips between the continental Germanic languages were with regard to the translations of the psalms, while the Old English versions prove to be isolated, opting in many cases for specifical lexical choices
Exploiting the generative design potential to select the best conceptual design of an aerospace component to be produced by additive manufacturing
No full textSince the advent of Industry 4.0, the manufacturing sector has had to face new challenges, which require the development of new skills and innovative tools. This scenario includes innovative production processes such as additive manufacturing (AM), a technology capable of producing a component layer-by-layer directly from the 3D model without needing specific tools during the building phase. Generative design (GD) may represent an opportunity to maximise the potential of AM techniques. GD is based on parametric computer-aided design (CAD) tools capable of generating multiple optimised outputs, among which the designer could select the most promising solution. This paper presents a general methodology for evaluating the GD outputs in the conceptual phase of design to select the best possible solution through a series of criteria at several levels. The evaluation method is deployed in an aerospace field case study. The procedure demonstrates the benefits of synergising GD with AM in the early stages of product development. This indicates that the developed methodology could reduce the number of iterations during the design process, and the result is a decrease in the overall time spent on the project, avoiding problems during the final stages of the design
La maturità di Alessandro Fei del Barbiere, in bilico tra Maniera e Riforma
No full textThis article studies the mature career of the Florentine painter Alessandro Fei del Barbiere (1537-1592), beginning with the rediscovery of the 'Ascension' altarpiece formerly in the Albizi Chapel in the destroyed church of San Pier Maggiore, Florence. Studying this painting and others recorded in 1584 by the biographer Raffaello Borghini, such as the two altarpieces for Santa Maria delle Grazie and the Madonna dell'Umiltà in Pistoia, the author reconstructs a body of works showing how in the 1580s Fei gradually went beyond the archaic style of his apprenticeship - he had been trained by Ridolfo del Ghirlandaio and Pierfrancesco Foschi, but was also marked by the Maniera of Vasari - evolving towards naturalism in both mimesis and pictorial handling. In Florence, his development partly parallels that of Santi di Tito and his circle, but Fei was also influenced by a probable sojourn during the early part of that decade in Rome, where he could have been inspired by Girolamo Muziano and the painters working for Pope Gregory XIII. Among other proposals, the author suggests that the artist was responsible for decorating the chancel of Fiesole Cathedral (c. 1584-1589), which consisted of an altarpiece, only rarely discussed by scholars, and a cycle of frescoes hitherto attributed to Nicodemo Ferrucci
Dimensional analysis of a prototype mould making process for thermoplastic Resin Transfer Moulding
No full textThe Resin Transfer Moulding (RTM) process is a low-cost process for the production of parts of composite material. However the economic convenience is lost when large components should be produced, because of the high tooling cost. The step milling of a resin master and the subsequent deposition of a nickel shell could be a valid alternative for the fabrication of an RTM mould. So far, information about the quality of this method of fabricating RTM moulds is lacking, thus more efforts are needed to quantify the error induced by the manufacturing sequence. In order to control the whole process and to assess the quality of the manufactured part, the dimensional deviation due to single manufacturing steps is evaluated for a reference part. Both traditional pointwise measurements and contactless scanning are used for dimensional inspection
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