Politecnio die Bari - Catalogo di prodotti della Ricerca
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Cowl: pushing OWL 2 over the Edge
No full textThe ever-complex information environments and rapidly expanding data volumes of the modern digital infrastructure demand efficient knowledge organization and retrieval techniques. The Semantic Web initiative has defined principles and technologies, such as the Resource Description Framework (RDF) and the Web Ontology Language (OWL), to create structured and semantically rich Knowledge Graphs. Current OWL toolkits, however, are largely unsuitable for resource-constrained platforms, hindering development of truly ubiquitous knowledge-enabled frameworks and applications. This paper introduces Cowl, an OWL manipulation software designed for a wide spectrum of devices, ranging from workstations to embedded systems with stringent resource limitations. Its architecture, optimizations, and novel processing techniques are detailed, emphasizing computation efficiency and minimal memory use, and providing actionable design principles for future toolkit developers. Comparative experiments reveal state-of-the-art performance and memory efficiency, and its versatility is demonstrated through a comprehensive evaluation on a popular microcontroller platform. Finally, a case study illustrates its usefulness in a knowledge-enabled smart city context
Eco-Friendly Materials and Products from the Waste Derived from the Processing of Apricena Stone: State of the Art and New Employment Prospects
No full textReduction of Ceramic Wear by Concave Dimples on the Bearing Surface in CoC Hip Implants: A Finite Element Analysis
No full textThe wear of hip prostheses represents a significant challenge for the longevity and functionality of joint implants. Recent studies have explored surface texturing of prostheses as a strategy to enhance tribological performance. This study aims to evaluate the impact of textured ceramic surfaces with dimples on wear and friction reduction in ceramic-on-ceramic (CoC) prostheses. Materials and Methods: Three-dimensional models of ceramic surfaces with and without dimples were created. Contact pressure was analyzed and wear volume was estimated using Archard’s law. Simulations were conducted using finite element methods (FEM) under various loading conditions. Results: Numerical simulations demonstrated that the wear rate for the dimpled femoral head was 0.2369 mm3/year, compared to 0.286 mm3/year for the smooth counterpart, highlighting a wear reduction of 17.2%. Conclusions: The integration of textured surfaces with dimples in ceramic prostheses can substantially improve their functionality and durability, representing a promising approach to addressing the issues associated with hip prosthesis wear
On some inequalities for the two-parameter Mittag-Leffler function in the complex plane
No full textFor the two-parameter Mittag-Leffler function Eα,β with α>0 and β≥0, we consider the question whether |Eα,β(z)| and Eα,β(Rz) are comparable on the whole complex plane. We show that the inequality |Eα,β(z)|≤Eα,β(Rz) holds globally if and only if Eα,β(−x) is completely monotone on (0,∞). For α∈[1,2) we prove that the complete monotonicity of 1/Eα,β(x) on (0,∞) is necessary for the global inequality |Eα,β(z)|≥Eα,β(Rz), and also sufficient for α=1. For α≥2 we show that the absence of non-real zeros for Eα,β is sufficient for the global inequality |Eα,β(z)|≥Eα,β(Rz), and also necessary for α=2. All these results have an explicit description in terms of the values of the parameters α,β. Along the way, several inequalities for Eα,β on the half-plane {Rz≥0} are established, and a characterization of its log-convexity and log-concavity on the positive half-line is obtained
Search for New Resonances Decaying to Pairs of Merged Diphotons in Proton-Proton Collisions at s=13 TeV
No full textA search is presented for an extended Higgs sector with two new particles, (Formula presented) and (Formula presented), in the process (Formula presented). Novel neural networks classify events with diphotons that are merged and determine the diphoton masses. The search uses LHC proton-proton collision data at (Formula presented) collected with the CMS detector, corresponding to an integrated luminosity of (Formula presented). No evidence of such resonances is seen. Upper limits are set on the production cross section for (Formula presented) between 300 and 3000 GeV and (Formula presented) between 0.5% and 2.5%, representing the most sensitive search in this channel
Passivation strategies for the optimization of perovskite solar cells
Get PDFThis thesis focuses on developing environmentally sustainable strategies to enhance the performance, stability, and scalability of PSCs, among the most promising PV technologies of the current scenario.
The experimental results are organized in three sections, chapters 3 to 5, the first one employing bio-derived materials as components of the PSC device foreseeing the amelioration of the photoactive film characteristics combined with the engineering of device interfaces. In details, chapter 3 reports on the use of β-carotene and PHB, to improve the environmental stability and optoelectronic properties of perovskite films. β-carotene, which scavenges oxidizing species, mitigates perovskite degradation, leading to increased material stability and prolonged charge carrier lifetimes. Devices incorporating β-carotene achieve a PCE of 20%, highlighting its potential to improve the lifespan and sustainability of solar cells. Similarly, PHB, a biodegradable polymer, enhances the mechanical flexibility and crystalline quality of perovskite films, and surpasses the reference efficiency, achieving a PCE of 9.3%. This suggests the potential of PHB to contribute to the development of more sustainable, flexible, and eco-friendly perovskite-based devices. The second section is focused on the key role of device interfaces for fully inorganic CsPbI3-based solar cells.
The incorporation of PCBM as an interlayer between C60 and CsPbI3 enhances energy level alignment and reduces defects, contributing to more efficient charge transfer. Successively, the introduction of TTH as a novel interlayer further improves device performance, with a PCE of 8.12% surpassing the reference efficiency of 6%, by reducing interfacial recombination and facilitating efficient charge separation. These innovations demonstrate the potential to optimize perovskite-based devices for more sustainable energy solutions.
Finally, in chapter 5 plasma-based treatments are explored as environmentally friendly surface modification methods for MAPbI3 perovskite films. Plasma treatments with gases like Ar and H2 enhance device performance by selectively removing organic components and introducing chemical functionalities that improve the stability and efficiency of the interfaces. Unlike traditional chemical treatments, plasma-based methods offer a less invasive and potentially more eco-friendly approach to surface engineering.
In conclusion, this thesis demonstrates the potential of combining bio-inspired additives, interlayer engineering, and plasma treatments to address key challenges in perovskite solar cell technology. These advancements not only improve the efficiency and stability of the devices but also pave the way for the development of more environmentally sustainable and scalable photovoltaic solutions, contributing to the global transition towards clean and renewable energy sources
Enhancing Utility in Differentially Private Recommendation Data Release via Exponential Mechanism
No full textDynamic Multi-Axis Calibration of MEMS Accelerometers for Sensitivity and Linearity Assessment
Get PDFA set of commercial triaxial micro-electromechanical systems (MEMS) accelerometers was calibrated using a custom-designed test bench featuring a rotating table. The calibration setup enabled simultaneous assessment of all accelerometer measurement components, generating precise reference accelerations within a frequency range of 0 to 8 Hz. A working model of the calibration setup and procedure was described to provide a complete uncertainty budget for both the reference and sensor accelerations. Through experimental uncertainty assessment of all the accelerometers, linearity and sensitivity were evaluated at different sensor levels. These parameters were determined by considering a single value for each accelerometer and detailing the analysis for each axis. Data processing revealed the achievable level of uncertainty and how it was influenced by the evaluation method employed for analyzing the calibration data
Next Generation of 3D‐Printed Electronics: Electroplating Inside Channels to Embed 3D Copper Features within Polymeric Structures Fabricated Through Material Extrusion
Get PDFMaterial Extrusion (MEX) 3D printing has been largely employed to process electrically conductive polymers to fabricate electronic components, which still suffer from bad performance due to high electrical resistance. The electroplating process is proven to drastically reduce the resistance by depositing a thin layer of copper on top of the electrically conductive polymer; however, this method comes with a price to pay: only external features can be plated with copper. The present research paper presents an innovative solution to overcome this issue by performing electroplating inside 3D-printed parts to plate internal layers (inaccessible for electroplating purposes with traditional approaches) with copper. Electroplating inside closed channels is performed: a remarkable reduction in electrical resistance of 5 orders of magnitude (from 2300 up to 0.08 Ω) is achieved in internal tracks. The proposed approach has also been implemented “on board” a commercial MEX machine to fabricate an assembly-free smart structure with a copper sensor completely embedded within dielectric material (improved performance compared to traditional counterpart). Furthermore, the proposed approach is proven to fully plate with copper not only planar tracks but also embedded 3D features such as coils. The present research unlocks the fabrication of assembly-free functional devices with embedded copper elements by only extruding polymers through MEX Additive Manufacturing
