102,028 research outputs found
INGARAO G (2014). Rosaria Vignolo Munson, Herodotus: volume 1, Herodotus and the narrative of the past. Oxford readings in classical studies. Oxford; New York: Oxford University Press, 2013. BRYN MAWR CLASSICAL REVIEW, ISSN: 1063-2948
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A comparative assessment of energy demand and life cycle costs for additive- and subtractive-based manufacturing approaches
No full textThe applicability domain of Additive Manufacturing (AM) processes, apart from technological and quality results, relies on environmental and cost performance. These aspects still need to be better understood. To this aim, comparative analyses with conventional manufacturing routes are needed. In this paper, empirical cost and energy requirement models are suggested to assess subtractive- (machining) and additive- (Electron Beam Melting) based manufacturing approaches for the production of Ti-6Al-4V components. A life-cycle perspective is adopted, and all the steps from the input material production to the post-AM processing operations and the use phase are included. The analyses have been carried out considering the shape of the component, the light-weighting capabilities and the utilization time as the main factors of influence. The proposed modelling effort has allowed different decision-support charts, which are suitable for identifying the most energy-efficient or economically-advantageous manufacturing approach, to be obtained. The results have revealed that, for the considered case study, EBM could be a more energy-efficient approach than conventional machining, even without re-designing the component, due to the higher efficiency in raw material usage. As far as cost is concerned, the additive-based approach only becomes the preferable solution when the cost savings during the use phase are accounted for
Se a grandi ingiustizie corrispondono grandi punizioni. Alcune riflessioni sul lessico della sanzione divina in Erodoto
No full textIn uno dei passi più rilevanti dell’opera Serse annuncia ai notabili persiani di voler conquistare la Grecia. L’attacco, secondo il ‘νόμος espansionistico’ inaugurato dai suoi predecessori, porterà non solo gloria all’impero persiano ma permetterà inoltre di conquistare una terra fertile e di ottenere finalmente “ἅμα τιμωρίην τε καὶ τίσιν”. Gli Ateniesi, che per primi hanno intrapreso azioni ingiuste contro la Persia, pagheranno per ciò che hanno fatto. Come rendere l’ideale retributivo espresso da questi due vocaboli utilizzati insieme? Esiste per lo storico di Alicarnasso una chiara distinzione tra un atto punitivo e uno meramente ritorsivo? Lo studio delle forme di causalità presenti nelle Storie, e nel dettaglio della punizione religiosa, induce ad interrogarsi sul lessico della sanzione divina in Erodoto. Τίσις e τιμωρίη sono nelle Storie tra i termini che vengono maggiormente utilizzati per indicare una pena sovrannaturale che colpisce chi viola le norme morali e religiose accettate dalla comunità. L’analisi dei passi in cui questi due vocaboli - e i termini ad essi apparentati - paiono riferibili a forme di influenza divina nelle vicende umane può contribuire a chiarire i meccanismi della sanzione sovrannaturale nelle Storie, ad abbracciare la Weltanschauung dell’autore, e ad addentrarsi nella temperie culturale dell’epoca
(Review) Johannes Brehm, Generationenbeziehungen in den Historien Herodots, Classica et Orientalia, Harassowitz Verlag, Wiesbaden, 2013.. SEHEPUNKTE, ISSN: 1618-6168
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Design of complex sheet metal forming processes: a new computer aided progressive approach
No full text(Review) Debra Hamel, Reading Herodotus. A Guided Tour through the Wild Boars, Dancing Suitors, and Crazy Tyrants of the History, in Incidenza dell'Antico. Dialoghi di storia greca, 12, 2014, 222-226
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A multi-objective Pareto design approach for simultaneous control of thinning and springback in complex stamping operations.
No full textAbstract
In sheet metal forming operations design, optimization problems have to be solved in
order to reach optimal process conditions. In these problems, there are some crucial
issues to be taken into account:
- most of the problems are multi objective problems, generally characterized by
conflicting objectives: the definition of proper parameters aimed to prevent both
springback and fracture is a typical example of an optimization problem in sheet metal
forming characterized by conflicting goals;
- in an industrial environment a great interest would be focused on the
availability of a cluster of possible optimal solutions instead of a single “almost
optimal” solution.
Taking into account all these issues, a multi-objectives optimization procedure based
on Pareto optimal solution search techniques seems a very attractive approach to deal
with sheet metal forming processes design.
In this paper, integration between numerical simulations, response surface
methodology and Pareto optimal solution search techniques was applied in order to
design a 3D complex stamping process. Two process parameters (blank holder force
and drawbeads penetration) were utilized as design variables to be optimized in order
to accomplish two different objectives: control thickness distribution along the
workpiece and avoid excessive geometrical distortions due to springback occurrence.
The final aim of the research is to develop a predictive tool able to identify a sort of
process window for the analysed operation also minimizing the computational effort
with respect to mono-objective optimization techniques or traditional trial and error
methods
Manufacturing strategies for efficiency in energy and resources use: The role of metal shaping processes
No full textManufacturing sector nowadays has to deal with the global need to reduce the environmental impact of human activity. As manufacturing accounts for a significant portion of the global CO2 emissions, scientific research should be addressed to understand the environmental impact of manufacturing processes and, in the meantime, to take advantage of their full potential in reducing the overall CO2 emissions. The present review paper aims at describing the role of metal shaping processes in reducing the environmental impact across different stages of metal components life. Actually, an increased consciousness concerning both the environmental performances of manufacturing processes and their potential to enable circular economy practices can uncover and unlock new energy and resource efficiency strategies.Besides the straightforward role in the manufacturing stage, the impact of these processes in others life stages (mainly material production and End-of-life) is analyzed. The review paper aims both at outlining the already developed scientific research in the domain of energy and resource efficiency and at highlighting the role of metal shaping processes in putting in place energy and resource efficient manufacturing strategies. Concerning the unit process level, quantified improvements in environmental indicators with varying processes parameters, machine tools architectures, used process and manufacturing approach itself have been analyzed. As far as material efficiency is concerned, both innovative recycling as well as reuse strategies (remanufacturing, reshape and relocate) implemented by means of metal shaping processes are described. The idea is to provide a comprehensive picture of environmental aspects of metal shaping processes analyzing the developed scientific research, looking at them from a new perspectives and outlining research needs
(Review) Munson, Rosaria Vignolo (ed.). Herodotus: volume 2, Herodotus and the world. Oxford readings in classical studies. Oxford; New York: Oxford University Press, 2013.. BRYN MAWR CLASSICAL REVIEW, ISSN: 1063-2948
No full textRecensione su rivist
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