Politecnio die Bari - Catalogo di prodotti della Ricerca
Not a member yet
36616 research outputs found
Sort by
Una casa a soffietto. La rappresentazione dell'interno architettonico nella scenografia teatrale
No full textLa finzione scenica, con particolare riguardo all’interno architettonico, ci consente di accedere laddove l’architettura può solo simulare la propria possibilità di veduta, attraverso la convenzione del disegno in sezione.
In teatro, invece, scoperchiando la cosiddetta “quarta parete”, entriamo concretamente, osservatori intrusivi e privilegiati allo stesso tempo, sin dove all’architettura non è consentito con questa stessa immediatezza. Ed ecco dischiudersi, secondo un’inedita angolazione, la stanza.
Abattuta la barriera visiva che si frappone, origina una straordinaria rappresentazione: finta, in quanto simulazione e imitazione della realtà, ma anche vera, in quanto dichiaratamente finta. Grazie a questa simulazione, che ci avvince in processi catartici, possiamo vedere visualizzata la vita umana, colta nei suoi momenti interni, interiori e intimi: miserie, affanni, speranze, paure, esorcismi, invidie, vendette, affetti, morale e anti-morale. Ma soprattutto, possiamo vedere come oltre a tutti i requisiti tecnologici, ergonomici e funzionalistici, la stanza diventi un tabernacolo, custode di tutti i valori simbolici che ruotano intorno alla vita umana, un ostensorio in grado di evocare visioni al di là del mondo strettamente fisico.
La “casa a soffietto”, citazione presa a prestito dalla letteratura teatrale, è dunque un dispositivo tecnico, ma anche evocativo, pronta a restituire - ogni volta che la si “aprirà” - il flusso emotivo ad essa inevitabilmente connaturato
Optimal Stochastic Management of Energy Storage Systems based on Non-linear Energy Reservoir Models
No full textThis paper discusses and extends energy-reservoir models (ERMs) for energy storage systems (ESSs), recently proposed in the related literature, by introducing a non-unitary efficiency for the discharging process. This enhancement allows the resulting ESS model to more accurately represent losses during both charging and discharging cycles, albeit at the cost of introducing a non-linearity. We show that, while the lower ERM capacity bound preserves convexity, the upper bound does not. Hence, a mixed-integer reformulation is provided to tackle such a non-convexity. We focus on the perspective of a prosumer equipped with an ERM and served by an energy retailer characterized by a realistic energy pricing scheme. We also account for the inherent uncertainty in ESS management related to the prosumer's energy demand and generation curves: to accommodate this uncertainty, our approach accepts probabilistic forecasts as inputs, enabling objective function approximation through techniques such as sample average approximation. The proposed approach is numerically validated using real data, implementing the formulation within a model-predictive-control framework
Broadband Circularly Polarized Antenna Array via Metasurface and Partially Emptied Substrate
No full textA metasurface including an empty region constituted by a square-shaped aperture is proposed to improve the performance of a circularly polarized patch antenna array based on sequential-phase feeding. The metasurface is applied/stacked to a conventional antenna consisting of a loop feeding structure, which enables sequential incremental phase to four patches. Surface waves propagating on the metasurface are excited, affecting the resonance features of the overall radiating structure, thereby improving both the input impedance-matching and the axial ratio bandwidths of the antenna. The square-shaped aperture in the top layer is introduced to extend the range of frequency over which the sequential phase feeding remains effective. The antenna prototype and the stacked metasurface are fabricated. The experimental results, in good agreement with simulation, show that the antenna with the compact size 2.16 λ0 × 2.16 λ0 × 0.12 λ0, at the central frequency, provides a broad impedance relative bandwidth of 43.8% from 11.6~GHz to 18.1~GHz and a 3-dB axial ratio bandwidth of 36.6% (from 11.6~GHz to 16.8~GHz ). In addition, the proposed antenna has a flat gain within the operating frequency band and a peak gain G=13.9 dBic at frequency f =1 4 GHz
High Speed Synchronous Machines: Technologies and Limits
No full textThis article presents a comprehensive comparison of high-speed synchronous machines, encompassing synchronous reluctance, its permanent magnet variant, and surface permanent magnet synchronous motors. The evaluation of their maximum performance capabilities employs a hybrid analytical-finite element design procedure able to address electromagnetic, thermal, and structural requirements simultaneously. Indeed, the adopted design methodology takes into account all the machines nonlinearities, while also including the limitations introduced by the iron ribs of the reluctance machine, retaining sleeve of the surface permanent magnet machine and increasing iron losses. The aim of the outlined design exercise is to evaluate the effect of different design specifications on the maximum achievable performance of the three machine topologies. A wide range of maximum design speeds, airgap thicknesses, and cooling system capabilities has been assessed showing when and why one motor type outperforms the others. The cooling system capability increment required by the reluctance-based machines to achieve the performance of the surface permanent magnet one has been systematically quantified. The design assumptions have been verified by a thermal analysis supporting the final machine selection. Three different machines designed with a maximum speed of 80 kr/min have been prototyped and tested on an instrumented test rig, validating all the design considerations
Machine learning-aided cloud analysis for seismic fragility assessment of multi-span bridges
No full textThe present study explores the implementation of machine learning (ML) algorithms in the context of the fragility analysis of existing multi-span reinforced concrete bridges composed of simply supported girders, accounting for the record-to-record variability and the uncertainty related to structural and mechanical parameters. The study compares a conventional cloud analysis based on nonlinear time history analysis (NLTHA) and a proposed ML-aided cloud method. In this latter, random forest and neural network models are trained to surrogate NLTHA in predicting the seismic demand of the piers. The ML-aided approach implements a novel strategy to optimise the choice of input features (seismic intensity measures and uncertain structural parameters) to be used for enhancing the model training. The accuracy of the method is discussed by comparing probabilistic demand models and fragility curves conditioned to variable uncertain parameters. In the case study application, the ML-aided cloud analysis, implemented by reducing the number of NLTHA to approximately one-third compared to the conventional approach, achieves high accuracy when using the random forest algorithm. This latter outperforms neural network leading to a lower number of required input features and improved performance metrics. In conclusion, the outcomes are used to propose a novel ML-aided cloud analysis approach for future applications of bridge risk assessment
Towards the Integration of Terrestrial and Non-Terrestrial Networks: a Testbed for in-Lab Evaluation
No full textSecurity of hybrid BB84 with heterodyne detection
No full textQuantum key distribution (QKD) promises everlasting security based on the laws of physics. Most common protocols are grouped into two distinct categories based on the degrees of freedom used to carry information, which can be either discrete or continuous, each presenting unique advantages in either performance, feasibility for near-term implementation, and compatibility with existing telecommunications architectures. Recently, hybrid QKD protocols have been introduced to leverage advantages from both categories. In this work we provide a rigorous security proof for a protocol introduced by Qi in 2021, where information is encoded in discrete variables as in the widespread Bennett Brassard 1984 protocol but decoded continuously via heterodyne detection. Security proofs for hybrid protocols inherit the same challenges associated with continuous-variable protocols due to unbounded dimensions. Here we successfully address these challenges by exploiting symmetry. Our approach enables truncation of the Hilbert space with precise control of the approximation errors and lead to a tight, semi-analytical expression for the asymptotic key rate under collective attacks. As concrete examples, we apply our theory to compute the key rates under passive attacks, linear loss, and Gaussian noise
3D printed microfluidic devices produced by material extrusion: effect of ironing parameters on mixing efficiency and gradient generation
No full textPurpose: This study aims to describe the effect of ironing process parameters on mixing efficiency and gradient generation in Y-micromixers and microfluidic gradient generators (MGGs), respectively. Design/methodology/approach: Material extrusion (MEX) enables the production of miniaturized devices with the advantage of lower manufacturing costs and higher design freedom. However, surface finishing is the most important drawback when it comes to microfluidic applications where flow splitting is not required. First, the effect of ironing line spacing (LS) and speed (IS) on mixing efficiency in Y-micromixers was experimentally investigated. Then, the best ironing settings were chosen to further study the spatial stability of the normalized concentration gradient in MGGs. Findings: Lower ironing LS and IS enhance the microchannel surface smoothness. The best combination of ironing parameters (lowest values of LS and IS) leads to an increase in mixing length of 191% at Q = 10 μL/min and 198% at Q = 20 μL/min, with respect to a similar Y-micromixer geometry where ironing was not performed. These findings were applied in the production of a MGG, showing that the normalized concentration gradient in the crosswise flow direction does not depend on the streamwise position when ironing is performed. Originality/value: To the best of the authors’ knowledge, for the first time, the possibility of optimizing ironing parameters to enhance the surface roughness in MEX microfluidic devices has been investigated. Ironing of the channel bottom surface allows to reduce ridges-induced flow convection, thus delaying mixing in Y-micromixers and achieving stable concentration gradient in MGGs
Architetture all'opera. Scenografie per il teatro musicale
No full textTesto letterario e scenografia sono esattamente l’anima e il corpo della rappresentazione teatrale. E allo stesso modo in cui senz’anima il corpo non si muoverebbe, o senza corpo l’anima non si manifesterebbe, analogamente in teatro, per dare vita alla messa in scena, occorre che testo letterario e scena costruita siano in sinergia.
La scena non è solo il luogo dell’azione, la semplice ambientazione funzionale al dramma. La scena è soprattutto evocazione simbolica, è repêchage dal mondo degli archetipi, è slancio profetico, dal momento che solo gli aspetti performativi della rappresentazione godono di piena libertà interpretativa. Questi valori simbolici sono particolarmente presenti nella rappresentazione scenica dell’interno architettonico, in particolare quello domestico. Stavolta, forte della finzione scenica, la casa non deve espletare i suoi aspetti pratici e funzionalistici, ma incarna principal- mente quelli simbolici, ora secondo le intenzioni dell’autore del testo, ora secondo l’interpretazione del metteur en scène, o infine, secondo la sensibilità percettiva dello spettatore.
Queste ed altre riflessioni, che Santi Centineo riporta in queste pagine, scaturiscono dal racconto dei suoi vent’anni di carriera come scenografo, dai piccoli festival e teatri di provincia, sino ai grandi enti lirici, in Italia e all’estero, attraverso titoli di repertorio o desueti, incrociando numerosissimi artisti, personaggi, lavoratori