University of Modena and Reggio Emilia
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Developing Tailored Materials for the Industrial Production of Anion Exchange Membrane Electrolyzers through a Statistical Approach
Get PDFA simple approach to transient-state modeling of nitrogen cooling in the extrusion of light-alloy complex profiles
No full textNitrogen cooling has become a popular solution to reduce heat flux between the die and the profile in the hot extrusion process. However, designing effective cooling channels for complex-shape profiles poses challenges, especially when the phase transition of nitrogen significantly impacts heat transfer with solid bodies. To this end, the ability to model both the liquid and the gas phase is instrumental in devising design strategies, yet it should be combined with low computational complexity for industrial applications. The present work is aimed at employing the homogenous-flow approach as a simple, yet representative methodology to consider both phases in the simulations. One-dimensional model of nitrogen was combined with a three-dimensional extrusion model to perform the transient analysis of the whole process, mostly focused on the transition from fully gaseous to fully liquid flow. Validation using extrusion tests on seventeen AA6060 billets demonstrates the model's predictability in comparison with a fully liquid model. The average error associated with Homogeneous Flow Model was evaluated as below 10%, whereas the fully liquid approach yielded 25%. That proved the ability of the proposed model to reproduce the cooling effect, thus supporting the design of the cooling subsystem within the context of the whole extrusion tooling
The Bright Side of Price Volatility in Global Commodity Procurement
No full textThis paper studies two competing firms’ choices between the contingent-price contract (CPC) and fixed-price contract (FPC) in global commodity procurement. The FPC price is determined when signing the contract, whereas the CPC price is pegged to an underlying index and remains open until the delivery date. Under both contracts, each firm determines its order quantity based on the updated belief about the market demand. The unrealized CPC price correlates with the market demand, allowing a firm to update its belief about the CPC price using demand information, thereby generating a price-learning effect. We find that, contrary to conventional wisdom, a larger price volatility could benefit the firms, and, under differentiated contracts, a firm might benefit from the improvement of forecast accuracy at its rival. We further show that the price-learning effect plays a critical role in the firms’ contract choices. First, significant price volatility forces the firms to pursue the responsiveness of the CPC. Second, the firms may adopt differentiated contracts to enhance their responses to market changes and dampen competition, and a higher competition intensity more likely leads to contract differentiation. Third, the firms in a small market seek responsiveness and contract differentiation rather than cost efficiency. This study reveals the bright side of price volatility and takes a step toward understanding the effect of two-dimensional information updating
Mask and Compress: Efficient Skeleton-based Action Recognition in Continual Learning
Get PDFThe use of skeletal data allows deep learning models to perform action recognition efficiently and effectively. Herein, we believe that exploring this problem within the context of Continual Learning is crucial. While numerous studies focus on skeleton-based action recognition from a traditional offline perspective, only a handful venture into online approaches. In this respect, we introduce CHARON (Continual Human Action Recognition On skeletoNs), which maintains consistent performance while operating within an efficient framework. Through techniques like uniform sampling, interpolation, and a memory-efficient training stage based on masking, we achieve improved recognition accuracy while minimizing computational overhead. Our experiments on Split NTU-60 and the proposed Split NTU-120 datasets demonstrate that CHARON sets a new benchmark in this domain. The code is available at https://github.com/Sperimental3/CHARON
Electrochemical sensors for fast classification of different Cannabis sativa L. samples according to total Δ9-tetrahydrocannabinol content
Get PDFApproximation of functionals with generalized Orlicz norms
No full textThe aim of this paper is to deal with the asymptotics of generalized Orlicz norms when the lower growth rate tends to infinity. We generalize results proven by Bertazzoni, Harjulehto and Hasto in Journ. of Math. Anal. and Appl. (2024) for integral type energies (in generalized Orlicz spaces), considering milder convexity assumptions. Gamma-convergence results and related representation theorems in terms of L-infinity functionals are proven. The convexity hypotheses are completely removed in the variable exponent setting, thus extending the results in Eleuteri-Prinari in Nonlinear Anal. Real. World Appl. (2021) and Prinari-Zappale in JOTA (2020)
Comprendere le storie di vita degli animali: Analisi elementari e isotopiche di denti fossili ad alta risoluzione spaziale
No full textLa geochimica isotopica è diventata uno strumento fondamentale nella ricerca (paleo)ecologica e (zoo)archeologica. La misurazione degli isotopi stabili e radiogenici sui tessuti scheletrici faunistici permette di indagare le loro storie di vita, altrimenti destinate a rimanere sconosciute. I progressi degli strumenti analitici e geostatistici consentono oggi di studiare diversi aspetti della (paleo)ecologia animale, tra cui gli spostamenti (anche stagionali), le preferenze di habitat e i cambiamenti nella dieta, facendo allo stesso tempo luce sulle interazioni uomo-animale in ambienti in continuo cambiamento. Al centro di questo lavoro ci sono le analisi isotopiche di 87Sr/86Sr, δ18O e δ13C su smalto dentale e ossa, applicate a diverse risoluzioni spaziali su una vasta gamma di resti faunistici datati dal Pleistocene medio ai tempi moderni. In alcuni casi, analisi complementari come quelle dell'amelogenina, della ZooMS e del DNA antico sono state eseguite in laboratori esterni se necessarie per rispondere a specifiche domande di ricerca. Le analisi degli isotopi 87Sr/86Sr sono state eseguite con uno spettrometro di massa multi-collettore con plasma accoppiato induttivamente (MC-ICP-MS), talvolta anche accoppiato a un sistema di ablazione laser (LA-MC-ICPMS) per misurazioni in situ ad alta risoluzione spaziale. Le analisi degli isotopi stabili δ18O e δ13C, sia bulk che sequenziali, sono state condotte mediante la spettrometria di massa per il rapporto isotopico (IRMS). I casi studio sono presentati in ordine cronologico partendo dal più antico. Il primo caso studio riguarda l'estinto elefante dalle zanne dritte (Palaeoloxodon antiquus). L'ecologia di questa specie viene esplorata attraverso analisi isotopiche 87Sr/86Sr in situ ad alta risoluzione e C-O sequenziali su molari di P. antiquus provenienti dal sito di Neumark-Nord (Ultimo Interglaciale, Sassonia-Anhalt, Germania). Nel secondo caso studio vengono presentate le analisi isotopiche condotte sullo smalto di denti di stambecco paleolitico (Capra ibex), comprendenti l'analisi 87Sr/86Sr bulk e l'analisi sequenziale degli isotopi C-O, insieme ai risultati dell'amelogenina e del DNA antico. Questi risultati forniscono approfondimenti sull'ecologia e l'evoluzione dello stambecco a Riparo Dalmeri (TN, Italia) e sul paleoambiente dell’importante periodo di transizione tra Pleistocene e Olocene. Il terzo caso studio è incentrato su ovicaprini islamici, il cui smalto dentale è stato oggetto di analisi Sr-C-O sequenziali. Questi risultati, combinati con l'analisi ZooMS per distinguere pecore e capre, offrono nuovi spunti per lo studio delle strategie di gestione degli animali nel sito di Kafir Kala (Samarcanda, Uzbekistan) durante il periodo altomedievale. Infine, il quarto caso studio riguarda alci moderne selvatiche abbattute in varie località della Svezia. Sono state condotte analisi isotopiche bulk di Sr, C e O su ossa e corna per studiare l'ecologia degli alci, comprese le abitudini alimentari e la mobilità, con l'obiettivo di fornire un esempio moderno utile per futuri studi (paleo)ecologici e (zoo)archeologici. Inoltre, l'Appendice comprende una collaborazione con l'Università di Padova per la creazione del primo isoscape Sr della Sardegna meridionale.Isotope geochemistry has become a fundamental tool in (paleo)ecological and (zoo)archaeological research. The measurement of both stable and radiogenic isotopes on faunal skeletal tissues offers insights into their past life-histories that would otherwise remain unknown. Advances in analytical and geostatistical tools now enable the investigation of different aspects of animal (paleo)ecology, including (seasonal) movements, habitat preferences and dietary shifts, while also shedding light on human-animal interactions in changing environments. The focus of this work is on 87Sr/86Sr, δ18O and δ13C isotope analyses of tooth enamel and bones, applying different spatial resolutions to a diverse range of faunal remains spanning from the Middle Pleistocene to modern times. In some cases, complementary analyses, such as amelogenin, ZooMS and aDNA, were carried out in external laboratories when required to address specific research questions. 87Sr/86Sr isotope analysis were performed using a Multi-Collector Inductively-Coupled Mass Spectrometer (MC-ICP-MS), also coupled to a laser ablation system (LA-MC-ICPMS) for in situ spatially-resolved measurements. Both bulk and sequential δ18O and δ13C stable isotope analyses were conducted by Isotope Ratio Mass Spectrometry (IRMS). The case studies are presented in chronological order starting from the most ancient. The first case study deals with the extinct straight-tusked elephant (Palaeoloxodon antiquus). The ecology of this species is explored through in situ high-resolution 87Sr/86Sr and sequential C-O isotope analyses of P. antiquus molars from the Last Interglacial site of Neumark-Nord (Saxony-Anhalt, Germany). In the second case study, isotopic analyses of Palaeolithic ibex (Capra ibex) tooth enamel are presented, including bulk Sr and sequential C-O isotope analysis, alongside amelogenin and aDNA results. These analyses provide insights into ibex ecology and evolution at Riparo Dalmeri (TN, Italy) and into the paleoenvironment of the key Pleistocene-Holocene transition period. The third case study investigates Islamic ovicaprids through sequential Sr-C-O isotope analyses. These results paired with ZooMS analysis to distinguish sheep and goats offer new insights into the study of animal management strategies at the site of Kafir Kala (Samarkand, Uzbekistan) during the Early Medieval period. Finally, the fourth case study involves modern wild-shot moose from various locations across Sweden. Bulk Sr, C and O isotope analyses are conducted on bones and antlers to study moose ecology, including dietary habits and mobility behaviour, with the aim of providing a modern workflow for future (paleo)ecological and (zoo)archaeological studies. Additionally, the Appendix includes collaborative work with the University of Padua on the creation of the first Sr isoscape of southern Sardinia
Monopoly Power upon the World of Work: A Workplace Analysis in the Logistics Segment Under Automation
No full textThis paper aims to investigate the impact of monopoly power on the world of work within the logistics segment, particularly in the context of automation processes. We conduct a fieldwork analysis of three workplaces situated in Italy, each owned by distinct types of monopolies: a corporate monopoly, Philip Morris, the global leader in tobacco and cigarette production; a state-owned monopoly, Poste Italiane, the exclusive public provider of mail services within the national borders; and a novel form of digital monopoly that holds control over intangibles and exhibits monopsonistic control over labour - Amazon. Through a comparative examination of these three diverse forms of monopolies, utilising corporate-level metrics and patent data, we scrutinise the restructuring of labour processes following the introduction of Automated Guided Vehicles. Employing a qualitative analysis that includes semi-structured interviews with HR professionals, IT specialists, and workers, we underscore that powerful monopolies play a crucial role in shaping the trajectory of technological development, adoption, and utilisation. Despite notable distinctions observed among the three cases, we document a common trend of standardisation and codification of human activities when interfacing with automated machines
Role of iron-rich clays on sintering of porcelain stoneware tiles
Get PDFPorcelain stoneware traditionally contains low Fe2O3 (<1 wt%), limiting research on iron's effects beyond coloration to date. However, recent changes in the supply chain induced a shift towards resource efficiency and circular economy, which led to body formulations with Fe2O3 up to 2.5 wt%. This study investigates the impact of iron-rich clays on the firing behaviour of porcelain stoneware, focusing on sintering processes, Fe speciation, and physical properties of the vitreous phase. Results show that red clays influence vitrification paths and maximum densification temperature, as well as composition and properties of the melt. This occurs not only because the relatively high iron percentage (up to 1.7 wt%), but for a set of factors, like the overall mineralogical and chemical composition of batches. Iron turns to be crucial for the stability of ceramic bodies at high temperatures, since Fe3+ can partially reduce to Fe2+, releasing gases and contributing to bloating phenomena
Lower and upper bounds for scheduling a real-life assembly problem with precedences and resource constraints
No full textIn this work, we consider a real-life scheduling problem involving the production of off-road vehicles using a three-level assembly process, subject to precedence, machines, and resource constraints. This problem shares multiple characteristics with other scheduling problems such as the Parallel Machine Scheduling and Flexible Flow Shop Problems. However, it also comprises less investigated aspects such as a specific job precedence structure resulting in a directed rooted in-tree and a global resource constraint limiting the number of simultaneously active machines. We present a straightforward adaptation of a time-indexed mathematical formulation to the problem and introduce a new lower-bounding procedure. To solve the problem, we propose constructive heuristics based on classical priority rules and adaptations of job sequencing heuristics. We also propose CORE, a specialized approach tailored to leverage the problem structure. All the algorithms are extensively evaluated on two benchmark sets, various shop floor configurations, and eight real-life scenarios. Our results reveal the general effectiveness of job sequencing approaches and demonstrate the overall superiority of CORE