Archivio istituzionale della ricerca - Alma Mater Studiorum Università di Bologna
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Impact of die design and bearing geometry on grain size and PCG formation during extrusion of AA6082 aluminum alloy
No full textGrain size and formation of the Peripheral Coarse Grain (PCG) defect influence the mechanical and crash properties of extruded profiles. Controlling microstructural evolution during the extrusion of 6XXX series aluminum alloys is therefore essential to ensure the performance of structural components. In this work, three profiles with the same nominal geometry were extruded with a die comprising three different bearing geometries to create different extrusion conditions. Each profile was analyzed experimentally to gather data on the microstructure and mechanical properties. Bulge testing revealed that Profile 2, with the thickest PCG layer (490–1150 μm), exhibited worse mechanical performance, with a hoop strain at fracture of 0.08 and a peak load of 51.5 kN, compared to Profiles 1 and 3, which had higher hoop strains (0.13 and 0.14) and peak loads (56.1 and 57.6 kN, respectively). Finite Element Method (FEM) simulations of the extrusion process were carried out using Qform Extrusion UK with a post-processing subroutine developed and implemented to calculate additional parameters such as the stored energy, percentage dynamic recrystallization, grain size, and PCG formation based on standard output parameters from the simulation including strain, temperature and strain rate. The simulation demonstrated that the highest strain rate (40–220 s−1) and stored energy (150,000–440,000 J m−3) in Profile 2 led to the thickest PCG layer. Based on these results, the proposed predictive model was validated against experimental data, demonstrating high accuracy in predicting PCG thickness and grain size while effectively capturing the influence of process parameters on microstructural evolution
The Anthill Model of collective intelligence in AI systems: some critical concerns for social justice and democratic education
No full textThis contribution is focused on the concept of “collective” intelligence and its reinterpretation in the contexts of digital platforms. I will claim that today’s AI systems, and the tech companies that control them, in most cases appear to embody a conception of collective intelligence that could be defined as “Anthill Model”. This model consists in a system that as a whole exhibits an intelligent behaviour, even though the individual participants contribute to it mainly being unaware of the way the systems functions and of the role they play in it. Such a model entails some deeply problematic implications in terms of social justice and democratic education: firstly, it appears in contrast with the promotion of critical and autonomous thinking. Secondly, appears to be in line with an educational ideal aimed at providing quality education only to a privileged minority, reducing investment in the education of the majority of the population. I will conclude proposing some questions: is the presented scenario an inevitable
doom, or is it still possible to act trying to promote a different future? Is it possible to use digital technologies to design forms of collective intelligence which are not conceived as an anthill, but rather as a dialogic community
Geometrical characterization of circular multi-layered CMT WAAM specimens by 3D structured light scanning
No full textTo ensure the geometric accuracy of wire arc additive manufacturing (WAAM) components, it is essential to analyze how process parameters influence the weld bead dimensions and shape. This paper presents a formal and repeatable procedure to entirely characterize the geometry of beads by enhanced full-coverage optical scanning with focus on multi-layered thin-walled closed specimens realized by the cold metal transfer (CMT) welding process. A series of circular specimens have been manufactured according to a DOE plan of process parameters, scanned with a GOM fringe projection 3D optical scanner, geometrically processed in the Rhinoceros 3D CAD environment, and analyzed by statistical indices according to the ANOVA approach. Average dimensions, lateral surface waviness, interaction between successive layers, and the torch switch-on/off zone of closed layer paths have been assessed. Numerical correlations between bead sizes and deposition parameters have been established. The obtained results also reveal shape and dimensional variability, highlighting the challenges in controlling geometry accuracy. Finally, process planning guidelines are formulated based on such results
Characterization of New Flavored Oils Obtained Through the Co-Milling of Olives and Vegetable Food Products
Get PDFConsumers are increasingly attracted to innovative, gourmand, and sustainable food products. This has led to a growing interest in flavored olive oils through co-milling processing. This study explores the production and characterization of flavored olive oils obtained by co-milling olives with orange pomace, black pepper, and hemp seeds, aiming to enhance their sensory and compositional properties while promoting sustainability through the valorization of agri-food by-products. The flavored olive oils and their control samples were analyzed for free acidity, tocopherols, phenolic compounds, volatiles, and sensory profiles. The flavored oils exhibited an acceptable hydrolytic state and peculiar sensory notes, depending on the ingredients used, as well as enhanced compositional qualities. This research highlights the potential of using oranges and hemp by-products in flavored oil production, offering an innovative approach to reducing food waste, with the possibility of future industrial applications
Balancing storage cost and customization time in product platform design: a bi-objective optimization model
Get PDFIn the modern market scenario governed by the Mass Customization paradigm, the so-called delayed product differentiation (DPD) rose as a production strategy best balancing traditional Make-to-Stock (MTS) and Make-to-Order (MTO), potentially reducing storage cost and customization time. In industry, DPD uses product platforms, defined as a set of components forming a common structure, from which a stream of derivative variants is produced. Early-stage platforms, made of few components, limit their storage cost, increasing the time to customize and turn them into final variants. The literature widely discusses the product platform design problem, asking to explore quantitatively the trade-off between platform storage cost and customization time. This paper contributes to applied research in mass customization, proposing and applying a bi-objective optimization model able to assign the most suitable production strategy to each product variant among MTS, MTO, and DPD. In the case of DPD selection, the model designs the product platforms best balancing storage cost and customization time as the target metrics to optimize, subject to industrial constraints to produce and store them, matching each variant to the most suitable platform. A case study adapted from the electronic components sector exemplifies the use of the bi-objective model, supporting companies in managing high-variety mixes
La gestione degli impianti sportivi tra affidamenti diretti e procedure competitive. Note a margine del parere di AGCM del 5 febbraio 2025
Get PDFLa nota analizza le procedure ad evidenza pubblica che gli enti pubblici sono tenuti a rispettare nell'affidamento della gestione dei propri impianti sportivi alle associazioni dilettantistich
Fortified or passito sweet wines from Aleatico grapes subjected to different dehydration conditions: chemical and aromatic profile using destructive and non-destructive analyses
Get PDFSweet or fortified wines hold significant cultural and economic value, particularly in regions where they are traditionally produced. Aleatico is a distinctive wine grape variety known for its unique aromatic characteristics, particularly used to produce sweet red wine. The drying technique significantly influences the wine's aroma and flavour profile. In the present study, the impact of different dehydration methods on Aleatico sweet and fortified wine quality was studied. Aleatico grapes were subjected to cold room (CR) dehydration (9 degrees C, 60 % RH) or room temperature (RT) dehydration (21 degrees C, 45 % RH) until 35 % of weight loss was reached. Dehydrated grapes were then fermented to obtain passito wines (Sweet RT, Sweet CR) or ethanol was added to the must to produce fortified wines (Fortified RT, Fortified CR). Non-destructive techniques (NIR-AOTF and E-nose) were applied for fast monitoring of wine differences together with chemical destructive analyses. At the end of the dehydration process significant increase in sugars and total extract was observed, without a significant difference between the two dehydration methods. Significant differences were observed in the time required to reach the fixed weight loss, with RT taking 19 days and CR only 47 days. Moreover, Sweet wines had a higher concentration of alcohols, esters, terpenes and ketones but lower aldehydes than Fortified wines. Sweet wines also had a higher concentration of organic acids but a greater susceptibility to oxidation, despite a higher and chemically more uniform phenolic fraction. E-nose and NIR-AOTF were able to discriminate between Sweet and Fortified wines. However, E-nose present evident limitations in discriminating between different dehydration conditions
L’écriture translingue des femmes. Espace de médiation interculturelle dans le contexte multilingue francophone
No full textLes écritures translingues, par leur nature, mettent en valeur une expérience de l’entre-deux, de l’exil et de l’étrangeté typique de toute personne ayant comme langue maternelle une langue minoritaire. C’est le cas aussi « des territoires, comme les anciennes colonies, les zones frontalières [...], d’où il n’est pas nécessaire de s’éloigner pour vivre entre deux langues et pour se sentir en exil dans la sienne » (Montini, 2015 : 223). Nous allons présenter ici le cas de deux écrivaines innues, Naomi Fontaine et Natasha Kanapé Fontaine qui, vivant entre les langues, parviennent à créer par leur écriture translingue, narrative, poétique et théâtrale, de potentiels espaces de médiation interculturelle où peuvent se dessiner des parcours de réparation à la recherche d’une rencontre authentiquement renouvelée à l’intérieur de la société dans laquelle elles vivent
Exploring government-citizen interaction in public service performance assessment: trade-offs, synergies, and critical issues
Get PDFCitizens’ participation and direct initiatives are on the rise, including in assessing public service performance. Performance measurement and government-citizen interactions have been traditionally studied separately in public administration scholarship. To bridge this gap, this article integrates these two bodies of literature, proposing a typology of approaches to government-citizen interactions in public service performance assessment and highlighting their features. It also discusses the possible synergies and trade-offs emerging at the intersection between “interaction” and “assessment”. In particular, the article focuses on how relevance, reliability, and understandability shape and are shaped by the interaction between governments and citizens in both government-led and citizen-led initiatives of performance assessment. Finally, the paper puts forward a research agenda for the study of interactive forms of public service performance measurement