Politecnio die Bari - Catalogo di prodotti della Ricerca
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Performance and rangeability enhancement of a pump as turbine embedding variable Inlet Guide Vanes
No full textPumps as Turbines (PaTs), also referred to as Hydraulic Power Recovery Turbines
(HPRTs) in several industrial applications, are emerging as a viable solution for smallscale
hydropower applications. However, their efficiency at part-load conditions remains
a significant drawback due to the lack of an inlet flow control mechanism. Therefore, this
work, in collaboration with the industrial partner Nuovo Pignone srl, investigates the
feasibility of enhancing the operational range of a HPRT by embedding Variable Inlet
Guide Vane (VIGV). For this study, a low-specific-speed centrifugal pump is selected.
This machine has been retrofitted by embedding the VIGV between the volute cutwater
and the impeller while keeping the original pump body. To accommodate this modification,
the impeller has been trimmed to make place to the VIGV and its kinematics in
order to obtain a compact solution. A design methodology for the VIGV is presented,
surveying the best practices in Francis turbine guide vane design. Computational Fluid
Dynamics (CFD) analyses are conducted to evaluate the flow characteristics before and
after the VIGV installation, providing insight into loss mechanisms and performance
variations. The results highlight a 25% improvement in part-load efficiency. Additionally,
the VIGV increased the rangeability of the machine by 0.25 of the flow rate at the
best efficiency point (BEP). Furthermore, a cycle-based analysis of variable operating
conditions demonstrates a 25% increase in harvested power. These findings confirm that
embedding a Variable IGV substantially improves PaT performance, making them a
more efficient and adaptable solution for energy recovery applications
Full-field analysis of semi-transparent cenosphere-filled composites using backlight illumination
No full textThis study introduces a novel approach for measuring deformations in semi-transparent composites using digital image correlation (DIC). Unlike traditional approaches relying on artificial speckle patterns, this method uses backlighted cenosphere particles dispersed in a semi-transparent matrix as intrinsic speckle patterns, eliminating the need for surface painting. The effectiveness of the intrinsic pattern is evaluated by comparing global parameters, such as speckle size, distribution, coverage, Shannon entropy and Mean Intensity Gradient, with those of a conventional pattern. Results indicate a relationship between speckle characteristics and measurement accuracy. A factorial design is employed to optimize DIC analysis parameters, including facet size, grid spacing, and filtering, resulting in a significant reduction in noise. Rigid displacement and four-point bending tests confirm the pattern's traceability, with results compared against a numerical model. This approach lays the groundwork for future investigations of transparent and semi-transparent materials using DIC, allowing comprehensive mechanical characterization without altering material transparency
Exploring the role of finance in driving circular economy and sustainable business practices
No full textThe existing economic system is mainly founded on a linear approach to gaining capital, including mining natural resources, manufacturing, consumption, and disposal. Despite the increasing attention given to the Circular Economy (CE), currently, scholarly analysis is absent into the function of finance and the prospective utility of financial developments in expediting the adoption of CE principles. Through a systematic literature review (SLR), this research aims to present a comprehensive understanding of the nexus between finance and the CE, emphasising how financial innovations can accelerate the transition towards CE. Considering 150 articles, it was found that financial innovation is a powerful driver for the transition towards a CE. Indeed, financial innovation enables organisations to integrate CE principles and environmental, social, and governance (ESG) elements into their strategic decision-making. This research unveils the need for more research and innovation in the financial sector to develop advanced financial instruments and mechanisms that can support CE acceleration. The acceleration of the global transition towards a sustainable, resource-efficient, and resilient economic model that benefits enterprises and society can be facilitated by promoting financial innovations. The analysis is grounded on the idea of CE as based on the tenets of designing out waste and pollution, keeping materials and resources in use, and regenerating natural systems. It turns out that CE is affected by a variety of factors with a final result of positive impact on the environment and society: green bonds, green loans, and finance; pay-for-performance and results-based financing mechanisms; specialised financing solution/CE-focused funds and investment strategies; and fintech in driving the CE. Finally, this study further provides new insights into the role of fintech, AI, and ML in advancing circular finance and scrutinising the hurdles and barriers to implementing circular finance practices
Risk analysis of crashes related to e-scoters: proposal of a predictive model
Get PDFThe rapid expansion of electric scooters has revolutionized urban mobility while raising significant safety concerns, particularly regarding crashes. This thesis presents a comprehensive study on the risk analysis of crashes involving electric scooters and proposes a predictive model to estimate the likelihood of crashes on urban road segments and intersections. Conducted in Bari, Italy, this research ad-dresses gaps in the literature by integrating data on electric scooter traffic, road ge-ometric characteristics, and infrastructure within a robust statistical framework.
The study begins with an analysis of crash data provided by the Local Police of Bari for the period 2021–2023. Descriptive statistics reveal critical insights into crash dynamics: 70% of the events resulted in injuries, highlighting the vulnerability of scooter users. Crashes predominantly occurred on undivided roads, underscoring potential infrastructure-related risks. The analysis also considers temporal and spa-tial patterns, providing useful insights for identifying high-risk conditions.
Data collection for this research followed an innovative approach, addressing the scarcity of standardized data on electric scooter traffic. Through collaboration with Vento Mobility Srl (TIER), access to usage statistics was secured, complement-ed by field surveys to estimate traffic volumes for both shared and private scooters. Additional information on road characteristics, vehicle traffic, and infrastructure was meticulously gathered using tools such as QGIS and Google Maps, ensuring a com-prehensive dataset.
A binomial logistic regression model was developed to predict the likelihood of crashes based on key variables such as daily traffic volumes, road geometry, and the presence of specific infrastructure like bicycle crossings or turning lanes. Models were separately developed for road segments and intersections, ensuring greater contextual relevance. Variables were selected based on statistical significance to en-hance the model accuracy while maintaining interpretability.
The predictive model results highlight key factors influencing the risk of crashes involving electric scooters. For intersections, high volumes of vehicular and scooter traffic significantly increase crash likelihood. Similarly, for road segments, variables such as segment length and traffic density emerge as critical predictors. These findings underscore the importance of targeted infrastructure improvements and traffic management strategies to reduce risks.
This thesis provide a validated predictive model that can support policymak-ers, urban planners, and transportation authorities. The study offers a practical tool to identify high-risk areas and implement safety interventions, promoting sustainable and safe micromobility in urban contexts.
By addressing both data collection challenges and the methodological limita-tions of previous studies, this research lays the groundwork for future studies on electric scooter safety. It advocates for the standardization of data collection and the adaptation of infrastructure to support the safe integration of scooters into urban transportation systems, even if changes in regulations should be taken into account in future studies
Retro-planning: a time machine for Cultural Heritage The urban gate S. Leonardo – Barletta (BAT)
No full textThe aim of this paper is to test the possibility of carrying out a back-
ward design process, based on historical and iconographic data, to reconstruct
an incomplete or destroyed heritage asset. By applying retro- planning, a reverse
design process based on historical data, the gool is to restore the cultural asset
studied to its original form, relocating it digitally, in the environment in which it
stood when it was conceived by its designer. The technique was applied to the S.
Leonardo gate in Barletta (BAT), which no longer exists today, but of which some
artefacts are preserved. At the end of the reverse design, with digital modelling, it
is possible to relocate the volumes of the architectural asset in the timeline to be
passed on to future generations so that it will not be forgotten.
At the basis of the process, in addition to historical and iconographic research,
it is necessary to investigate the construction techniques and materials in use at
the time of the architectural asset to be redesigned, which is fundamental in order
to create a model of the work as close as possible to the original. As will be seen,
the expanded knowledge of those approaching this reconstruction process plays
an important role, which most often starts with a few photographs and historical
data that are not very representative of the real architectural form. For this reason,
the intuitions of the operator are important in filling in the missing elements of
the reconstruction process. The procedure has as its goal the representation of
the cultural asset, elaborating in the drawings of the Mongiana representation
the aspects proper to architectural speech in order to construct the idea initially
elaborated by the creator of the work
CFD Analysis of the Impact of Building Shape on Natural Ventilation Effectiveness in High-Rise Buildings
No full textWith the increasing global emphasis on sustainability and high energy efficiency in buildings, natural ventilation is increasingly recognized as an effective passive strategy for reducing the cooling energy demand of buildings while ensuring indoor comfort and IAQ. Given its unstable nature and high dependence on building form, understanding and predicting how various aspects of building design impact natural ventilation effectiveness within the building becomes crucial to benefit it fully. This paper combines CFD analysis with building energy simulation to evaluate the effect of building shape on the cross-ventilation cooling potential of a real high-rise building in India. A comparative analysis of two distinct units with different shapes was conducted to evaluate the better shape for enhancing natural ventilation performance and thermal comfort. The results suggest proper orientation to prevailing winds, sizing and positioning of openings, optimization of indoor sections and interconnection between spaces are crucial in improving the effectiveness of wind-driven cross-ventilation. The unit with a higher ratio of inlet to outlet area (2:1 ratio) on the windward and leeward facades achieved a higher air exchange rate and average air velocity, ensuring an average 0.3 °C and a maximum up to 1.07 °C reduction in operative indoor temperature. The research outcomes provide valuable insights to optimize the building shape of high-rise buildings improving natural ventilation
Measurement of inclusive and differential cross sections of single top quark production in association with a W boson in proton-proton collisions at = 13.6 TeV
No full textThe first measurement of the inclusive and normalised differential cross sections of single top quark production in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13.6 TeV is presented. The data were recorded with the CMS detector at the LHC in 2022, and correspond to an integrated luminosity of 34.7 fb(-1). The analysed events contain one muon and one electron in the final state. For the inclusive measurement, multivariate discriminants exploiting the kinematic properties of the events are used to separate the signal from the dominant top quark-antiquark production background. A cross section of 82.3 +/- 2.1(stat)(+9.9)(-9.7)(syst) +/- 3.3(lumi) pb is obtained, consistent with the predictions of the standard model. A fiducial region is defined according to the detector acceptance to perform the differential measurements. The resulting differential distributions are unfolded to particle level and show good agreement with the predictions at next-to-leading order in perturbative quantum chromodynamics
Numerical modelling of geological processes as means for the diagnosis of ancient landslide mechanisms
No full textThe occurrence of deep paleo-landslides in marine clays is a well-documented phenomenon in multiple slopes within the south-eastern Italian Apennines and their associated foredeep basin. To accurately diagnose the mechanisms occurring in such landslides, a comprehensive numerical simulation of the processes leading to the initial slope failures is essential. This approach is only feasible when the geological history of the soil deposit has been meticulously evaluated. This paper presents a methodological procedure adopted to assist in diagnosing the current activity of a slow-moving, deep-seated ancient landslide using hydro-mechanical modelling. To investigate the processes leading to the initial slope failures, elasto-plastic finite element simulations have been conducted. These simulations aim to replicate the geological processes that the slope has experienced, which are identified as the key contributors to the landslide's inception. The application of this numerical modelling procedure has proven to be a valuable diagnostic tool, enhancing the understanding of the ancient landslide mechanism and providing insights into its current features, such as the position of the toe, landslide depth, and style of movement
Study of mechanical effects of probeless friction stir spot surface treatment on 3D-printed AlSi10Mg specimens
No full textPorosity and internal defects currently hinder the applicability of Laser Powder Bed Fusion (LPBF)-manufactured components. Innovative post-process methods specifically designed for the unique characteristics and microstructures of LPBF-manufactured aluminum alloys aim to suppress the porosity originating from the manufacturing process. Therefore, this study introduces a novel thermo-mechanical post-process treatment using flat surface tools – a probeless friction stir spot processing (P-FSST). Our results demonstrate that the imposed treatment plays a significant role in densifying the LPBF-manufactured specimens, while the treatment-induced distortions were highly dependent on the applied process conditions. The identified distortions on the upper surfaces of specimens, correlating with the imposed treatment, were mainly influenced by the dwell time. At the same time, the rotational speed majorly affected the presence of residual porosity in the central regions of the processed specimens. The results demonstrate that the P-FSST treatment significantly densifies the LPBF-manufactured specimens, achieving a reduction in porosity to under 0.4 % in sections treated at a rotational speed of 2000 rpm and various dwell times. The dwell time's influence on porosity was confirmed across treated regions, with significant decreases observable at a dwell time of 5 s, while further reductions correlated with increased dwell time and the thermomechanically affected zone. Distortions in the x-dimension were notably affected by dwell time (p-value = 0.011), whereas the y-dimension reflected the influence to both dwell time (p-value = 0.031) and rotational speed (p-value = 0.031)
The evolution of circular economy performance assessment: A systematic literature review
No full textCircular economy (CE) paradigm is applied in organisations at different levels (companies, supply chains, and ecosystems) to maximise resource use and minimize waste generation, presenting itself as an alternative to the traditional linear economy. However, a gap persists in the availability of standardised, comprehensive methods for assessing CE performance across diverse sectors and levels. Current methodologies often lack consistency, comparability, and applicability to complex systems, highlighting the need for further improvement, mainly considering the growing interest in adopting CE practices, also in compliance with emerging standards and frameworks (e.g., ISO 59000 and Digital Product Passport (DPP)). To support and theoretically ground the filling of these gaps, a systematic literature review (SLR) exploring the evolution of CE performance assessment methods has been conducted by considering as main drivers of analysis the type of variables analysed in the circular systems, the layer of the triple bottom line of the sustainability addressed, and the stage of the system lifecycle considered. It updates and compares the results obtained with those presented in a previous work analysing literature in the same domain up to 2018. The results showed that Life Cycle Assessment remains the most widely used method for lifecycle environmental impact assessment of circular systems, followed by Multi Criteria Decision Making, particularly in End-of-Life and for sustainability aspects. Alternative methods highlight the need for innovation, with some studies proposing industry-specific indicators or combined approaches. Finally, a comprehensive framework is needed to evaluate both positive and negative impacts; standardised Key Performance Indicators, aligned with ISO 59020:2024 and interoperable with DPP, would enhance consistency; and a unified methodology should be developed for CE assessment across all levels, ensuring resource efficiency and sustainability