Politecnio die Bari - Catalogo di prodotti della Ricerca
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Search for high-mass resonances in a final state comprising a gluon and two hadronically decaying W bosons in proton-proton collisions at = 13 TeV
No full textA 3D Lattice Boltzmann method for accurate wetting of ternary fluids with broad rheological variability
No full textA numerical framework is presented to predict the dynamics of droplets in contact with both hydrophilic and hydrophobic surfaces. We propose a three-dimensional Lattice Boltzmann solver based on the conservative phase-field method for ternary fluid systems. The interface evolution is retrieved by solving the conservative Allen–Cahn equation for two of the three phase-field variables involved in the ternary fluid system whose dynamics is governed by the mass and momentum equations. Such equations are discretized on the lattice nodes: the mass and momentum equations are described using a set of hydrodynamic distribution functions, while the Allen–Cahn equations using two sets of phase-field distribution functions. The boundary conditions for wettability are integrated using a novel non-equilibrium bounce back method for surfaces lying on the lattice nodes. The effectiveness of the solver is validated by means of several test cases of increasing complexity involving: droplets in a quiescent fluid for both low- and high- density ratios, spinodal decomposition of a ternary fluid system, the spreading of a liquid lens, and both static and dynamic configurations of droplets on wettable substrates. The results obtained throughout the validation show very good agreement with the related analytical solutions. A better conservation of physical variables at the boundaries is ensured, thus improving accuracy and mass conserving properties of the overall solver, especially in dynamic cases with high density- and/or viscosity- ratios. Finally, the deformation of a three-layer leukocyte under shear is investigated by means of three-dimensional simulations to demonstrate the effectiveness of the proposed framework
Angular analysis of the B0 → K⁎(892)0μ+μ− decay in proton-proton collisions at s=13TeV
No full textA full set of optimized observables is measured in an angular analysis of the decay B0→K⁎(892)0μ+μ− using a sample of proton-proton collisions at s=13TeV, collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 140 fb−1. The analysis is performed in six bins of the squared invariant mass of the dimuon system, q2, over the range 1.1<16GeV2. The results are among the most precise experimental measurements of the angular observables for this decay and are compared to a variety of predictions based on the standard model. Some of these predictions exhibit tension with the measurements
The Influence of Insertion Torque on Stress Distribution in Peri-Implant Bones Around Ultra-Short Implants: An FEA Study
Get PDFUsing ultra-short dental implants is a promising alternative to extensive bone grafting procedures for patients with atrophic posterior mandibles and vertical bone loss. However, the amount of insertion torque (IT) applied during implant placement significantly influences stress distribution in the peri-implant bone, which affects implant stability and long-term success. Materials and Methods: This study used finite element analysis (FEA) to examine how different insertion torques (35 N·cm and 75 N·cm) affect stress distribution in cortical and trabecular bone types D2 and D4 surrounding ultra-short implants. Von Mises equivalent stress values were compared with ultimate bone strength thresholds to evaluate the potential for microdamage during insertion. Results: The findings demonstrate that increasing IT from 35 N·cm to 75 N·cm led to a significant increase in peri-implant bone stress. Specifically, cortical bone stress in D4 bone increased from approximately 79 MPa to 142 MPa with higher IT, exceeding physiological limits and elevating the risk of microfractures and bone necrosis. In contrast, lower IT values kept stress within safe limits, ensuring optimal primary stability without damaging the bone. These results underscore the need to strike a balance between achieving sufficient implant stability and avoiding mechanical trauma to the surrounding bone. Conclusions: Accurate control of insertion torque during the placement of ultra-short dental implants is crucial to minimize bone damage and promote optimal osseointegration. Excessive torque, especially in low-density bone, can compromise implant success by inducing excessive stress, thereby increasing the risk of early failure
Credible Variable Speed Limits for Improving Road Safety: A Case Study Based on Italian Two-Lane Rural Roads
No full textIn an ever-changing driving environment where vehicles are becoming smarter, more autonomous, and more connected, a paradigmatic change in signals for drivers might be required. This need is correlated with road safety (social sustainability). There are several factors affecting road safety, and one of these, especially important on rural roads, is speed. One way to actively influence drivers’ speed is to intervene with regard to speed limit signs by providing credible and effective limits. This goal can be pursued by working on variable speed limits that align with the boundary conditions of the installation site. In this research, an analysis was conducted on the rural road network within the Metropolitan City of Bari (Italy) that involved collecting the speeds on each of the investigated two-way, two-lane rural roads of the network. In addition to the speeds, all the most relevant geometric details of the roads were considered, together with environmental factors like rainfall. A generalized linear model was developed to correlate the operating speed limits and other variables together with information about rainfall, which degrades tire–pavement friction and thus, road safety. After the development of this model, safety performance functions, depending on the amount of rain or number of days of rain, were calculated with the intent of predicting crash frequency, starting with the operative speed and rain conditions. Operative speed, speed limit, percentage of non-compliant drivers, traffic level, and site length were found to be associated with all typologies and locations of crashes investigated
Three Albanian cultural centers in comparison under an acoustic perspective
No full textAfter the World War II, Albania was governed by a dictatorship that lasted for about 50 years. The cultural life restarted to be one of the main centers of the society community. Many buildings styles reflected the influence of governors as leaders of countries, in combination with the spread of armed concrete used as the main material for new constructions, given its flexibility compared to brickwork that was not yet developed as it is nowadays. In Albania, many cultural centers were constructed for the local community where citizens can have access to libraries, coffee shops, and auditoria. These latest ones represent the places where live shows are performed, along with international conferences. This paper deals with the assessment of the acoustic response gathered within three auditoria as part of cultural centers in Albania. The acoustic measurements were carried out in accordance with ISO 3382-1. The acoustic response recorded inside the three case studies indicate a good listening condition for both speech and music performance. This outcome has been found in all three auditoria, despite the room volume between each other is different
ANALYSIS OF RAINFALL MONITORING NETWORK BY EVOLUTIONARY POLYNOMIAL REGRESSION
No full textIn Italy there is a rainfall monitoring network that has been built incrementally over the last 150 years following different logics and largely tied to the mere coverage of the territory, within the limits of the budget availability that has progressively become available over the years. In light of the changes in rainfall patterns resulting from the so-called "climate changes" underway, the need has emerged to understand whether this network is suitable for following the new dynamics in terms of land coverage and to allow detailed rainfall monitoring.
This study considers a part of this national network, consisting of 25 rainfall stations
located along the coast of the Ionian Sea in Puglia, managed by the Decentralized Functional Center of the Department of Civil Protection of the Puglia Region, Italy. The study analyzes precipitation data recorded at these stations over the last decades through a machine learning approach based on Evolutionary Polynomial Regression (EPR), aimed at revealing potential correlations between observations at different stations.
This analysis will be useful to analyze the level of land coverage by the stations and the possibility of predicting missing observations (gaps in the data) through observations in neighboring/related stations. The research has produced models with highly satisfactory levels of accuracy. Furthermore, the analysis of the correlations between the observations at the various stations has allowed to highlight situations in which the network needs integration
Advanced nanophotonics for gas spectroscopy
Get PDFThis thesis introduces advanced nanophotonic integrated devices aimed at improving minia-turized, cost-effective multi-gas detection and on-chip spectroscopic systems. Traditional spectroscopic techniques often require bulky optical components and multiple detectors, limiting their scalability for multi-gas sensing. The proposed integrated duplexers and tri-plexers enable switching between lasers to detect multiple gases using a single system. The work focuses on the design and optimization of broadband angled multimode interference duplexers, directional coupler-based duplexers, and cascaded directional coupler-based tri-plexers for combining spectroscopically relevant wavelengths in the near-infrared region. The target gases include ammonia, methane, and carbon dioxide. Through comprehensive simulations and experimental investigations, the proposed on-chip designs demonstrate su-perior performance compared to existing solutions and have a unique advantage in terms of smaller footprint and improved coupling efficiency. DC-based duplexer has been success-fully integrated with laser and GRIN lens components, resulting in a ready-to-use module for multi-gas sensing applications.
A semi-integrated photonic sensing system is presented, exploiting on-chip waveguides with Quartz Enhanced Photoacoustic spectroscopy and Light induced thermoelastic spec-troscopy (LITES). Side-polished optical fibers are explored to enhance light-matter interac-tion path when detecting water vapor and methane gases using LITES method. To further improve integration of integrated nanophotonic devices with spectroscopic devices and to enhance light-matter interaction, a novel wave confinement approach is introduced using high-contrast grating hollow core waveguides. These waveguides feature a reflective sur-face that maintains high transmission while allowing gas flow through the sidewalls, mak-ing them particularly suitable for gas spectroscopic applications. They are specifically op-timized for methane sensing at a wavelength of 3.27 μm. The final goal of this thesis is to develop a complete system that integrates a multiplexer with integrated lasers and high-efficiency interaction pathways, such as hollow core waveguides, into a spectroscopic de-vice. This compact and integration-friendly design holds great promises for enabling the development of portable, high-precision, and real-time multi-gas sensing devices for appli-cations from industrial, agricultural to environmental monitoring
Enhancing the Recovery Process for Historic Buildings through Virtual Environments Based on Panoramas Integrated with Informative System
No full textEffective collection and management of data are pivotal in the recovery process of architectural heritage. This is enhanced by the necessity to support multi-disciplinary analyses and process various data sources that need to be shared and interpreted by technicians for the assessment of buildings. Instead, digital evolution has encouraged scientific activities in using Virtual Environments (VEs) to overcome geometric and semantic complexities in the representation and analysis of historic buildings. It is the case of Virtual Tours (VTs), which result from the systematization of single spherical images and properly enhanced with thematic contents, ensuring a full fruition of the virtualized architecture also in an immersive way.
The chapter presents an operative flow for the setup of a VE, based on spherical images and integrated with an informative system, for the enhancement of the multi-disciplinary knowledge in the overall recovery process, from the systematization of technical knowledge to the diagnosis phase, the identification of causes and subsequent classes of intervention for historic buildings, starting from previous experiences. Specifically, the VE is structured as a unique digital tool where parallel VTs show thematic information and a relational database supports technical decisions of experts for causes and interventions, in a semi-automatic way. This aims at improving the overall quality of restoration design
Modulation of Asymmetric Magnetic Domain-Wall Motion via Noncolinear Interlayer Exchange Coupling
No full textThe search of scalable approach to design field-free deterministic switching is currently a key challenge. Here, we investigate current and magnetic driven magnetization switching in a T-type magnetic heterojunction with a structure composed by a hybrid synthetic antiferromagnet (SAF) Co/Ta/CoTb/Pt, where the bottom Co layer has in-plane magnetic anisotropy (IMA) and the top CoTb layer has perpendicular magnetic anisotropy (PMA). The interlayer exchange coupling (IEC) interaction allows a tilted easy axis of the perpendicular CoTb layer. The main result achieved is the field-free magnetization switching driven by spin-orbit torque (SOT) with a switching direction (clockwise or counterclockwise), which can be controlled by the in-plane direction of the Co magnetization. Meanwhile, we demonstrate that the IEC also induces the asymmetric bubble expansion in the CoTb layer in field-driven experiments and favors the propagation of the domain walls (DWs) with internal magnetization antiparallel to the in-plane IEC field. Our results demonstrate versatile control of the DW motion by noncollinear IEC, which paves a potential way for designing energy-efficient spintronic memory and logic devices, as well as provides a promising and high-efficiency approach for detecting the IEC type by magneto-optical Kerr effect (MOKE) in T-type magnetic heterojunction