Politecnio die Bari - Catalogo di prodotti della Ricerca
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Do We Really Need Specialization? Evaluating Generalist Text Embeddings for Zero-Shot Recommendation and Search
No full textCORRIGENDUM: MULTIPLE CONNECTING GEODESICS OF A RANDERS–KROPINA METRIC VIA HOMOTOPY THEORY FOR SOLUTIONS OF AN AFFINE CONTROL SYSTEM, (Topol. Methods Nonlinear Anal. (2023), 61, 1, (527–547), 10.12775/TMNA.2022.066)
No full textWe correct a mistake in our paper “Multiple connecting geodesics of a Randers–Kropina metric via homotopy theory for solutions of an affine control system”, Topol. Methods Nonlinear Anal. 61 (2023), 527–547. DOI: 10.12775/TMNA.2022.066. We acknowledge a mistake in Section 4 of [3] stemming from our misin-terpretation of a lower bound for the critical exponent pc in [2, Theorem 5]. Consequently, we cannot assert, as in [3, Theorem 4.1], that the set 1;p(x1) i
DEVELOPMENT OF BIMETALLIC CATALYSTS SUPPORTED ON METALLURGICAL WASTE FOR THIRD GENERATION BIODIESEL ENHANCEMENT
No full textInvestigating the Use of Augmented Reality and BIM for Architectural Heritage: A Systematic Review
No full textIn recent years, digital methodologies such as Building Information Modeling (BIM) and its specialised variants for historic architectural heritage (HBIM) have revolutionised approaches to the conservation, management, restoration,
and maintenance of existing architectures across various scales. The combined use of BIM/HBIM methodologies with immersive Augmented Reality (AR) technology enables the overlay of digital information onto real-world contexts,
enhancing data visualisation and user interaction. In these premises, this article explores the integration of AR-BIM/HBIM-based systems within architectural heritage at different dimensions and scales, providing an overview of their principal applications. To this end, a systematic literature review was conducted using the Scopus academic database. Following the PRISMA protocol, 17 records were identified and analysed. Outcomes highlight the single building as the predominant scope of application of the AR-BIM/HBIM-based system. This scale of the built environment facilitates conservation, management and maintenance disciplines, supporting users in digitalising documentation and providing diagnosis of critical issues. System of buildings follows as a scope with a focus on conservation, restoration and management, thanks to the development of systems that support the analysis, documentation and characterization of interventions. The least explored application scopes concern building components and historic districts. Despite
these achievements, future activities must focus on the possible levels of interoperability of AR-BIM/HBIM models, their continuous updating for monitoring activities and the easy accessibility and unambiguous understanding of content to
different classes of users
Combination of numerical and physical simulations as a new approach to the evaluation of the K-TIG welding process of thick duplex steel plates
No full textDuplex stainless steels, known for their resistance to corrosion combined with high yield strength, are increasingly used in offshore structures to reduce weight and material usage. The K-TIG welding process offers a solution to meet growing demands for the high-quality, cost-effective welding of duplex steel. It is a process in which, in contrast to the conventional TIG method, the application of high current intensity results in the formation of the so-called “keyhole” effect, enabling deep penetration even in materials of significant thickness. However, the limited flexibility of K-TIG method for modifying welding parameters for thick plates presents challenges. Moreover, different thermal cycles may occur across the weld thickness. This paper proposes an integrated approach combining numerical and physical simulation to optimize the K-TIG welding method for 10 mm duplex steel plates. A three-dimensional thermal model was developed using COMSOL Multiphysics, simulating the heat transfer and thermal cycles across the heat-affected zone, which was used in physical simulations conducted using a Gleeble 3180 system. The results show that thermal cycles vary significantly across the weld thickness, leading to microstructural differences that could influence the mechanical and corrosion properties of the welded joint. The proposed methodology provides an effective tool for optimizing the K-TIG process, offering insights into thermal cycles, microstructure evolution, and overall weld quality in thick duplex steel plates
Satellite Constellation Optimization for Emitter Geolocalization Missions Based on Angle of Arrival Techniques
No full textThe context of this study is the geolocation of signal emitters on the Earth’s surface through satellite platforms able to perform Angle of Arrival (AOA) measurements. This paper provides the theoretical framework to solve the optimization problem for the orbital deployment of the satellites minimizing the variance on the position error estimation with constraints on the line of sight (LOS). The problem is theoretically formulated for an arbitrary number of satellites in Low Earth Orbit (LEO) and target pointing attitude, focusing on minimizing the Position Dilution of Precision (PDOP) metric, providing a methodology for translating mission design requirements into problem formulation. An exemplary numerical application is presented for the operative case of the placement of a second satellite after a first one is launched. Simulation results are on angles of true anomaly, right ascension of the ascending node, and spacing angle, while accounting for orbital radius and emitter latitude. New insights on trends, parameter dependencies, and properties of symmetry and anti-symmetry are presented. The topic is of interest for new technological demonstrators based on CubeSats with AOA payload. Civil applications of interest are on interceptions of non-cooperative signals in activities of spectrum monitoring or search and rescue
Investigating EMI shielding performance of recycled polypropylene (PP) composite foams with reused metal powders
No full textSecondary raw materials, recycled Polypropylene (PP) and metal powders retrieved after use in the Powder Bed Fusion-Laser Beam process, are used to realize composite foams for microwave absorptance through chemical foaming. Morphological characterization allowed us to estimate foams’ relative density, cell size, distribution, and circularity. The results highlighted that metal powders contributed to air cell nucleation during the process, thus influencing the final foam morphology. Then, numerical analyses were conducted on modeled PP foams to calculate Scattering (S) parameters and Shielding Effectiveness (SE), varying air cell areas, shapes, metal particle distribution, and evaluating their impacts on EM response. Based on simulation results, the S-parameters of all samples were then measured in the X-band. The calculated SE contributions, SER and SEA, showed that foams with virgin and reused metal powders behave very similarly. Finally, four samples foamed from extruded pellets were characterized morphologically and electromagnetically. The outcomes showed extruded-based foams had a slightly decreased relative density, increased air cell numbers with lower circularity, and better uniformity in the air cell distributions. Confronting SE contributions in the X-band, SEA improved by about 10%-20% compared to the mixed samples
