1,720,972 research outputs found
Feasibility study of components manufactured using additive technology for the electrical sector
Full text linkL'abstract è presente nell'allegato / the abstract is in the attachmen
Measuring Thermal and Electrical Performances of Additively Manufactured Magnetic Shielding Material: An Active Thermography Approach
Full text linkThe thermal and electrical responses of additive manufactured specimens were analysed for a additive manufactured steel magnetic shield as a case study. The analysis was based on the evidence that variations in the thermal properties of a material can be measured as a phase delay in thermal diffusion through the material bulk. The signal post-processing was performed, and the results were presented in a phase diagram. The results showed that after heat treatment, the slope of the phase diagram changed to less steep, indicating an increase in thermal diffusivity and hence thermal conductivity. The electrical conductivity was predicted using the thermal conductivity and the Weidemann-Franz law and validated by experimental measurements of the electrical conductivity. The same approach was applied to predict the electrical conductivity in the magnetic shielding, taking into consideration the scaling of the density due to porosity. The results showed that the thermographic non-destructive full field non-contact approach can be used to evaluate the electrical properties of a component and that the heat-treated specimens show better thermal diffusivity and hence thermal and electrical conductivity
Advanced Feature Analysis of Eddy Current Testing Signals for Rail Surface Defect Characterization
No full textThe maintenance of the railways is of paramount importance for safe and reliable transport. Eddy Current Testing (ECT) provides high-resolution time-series signals that capture subtle anomalies on the rail surface. This paper expands on previous analyses by combining classical time-frequency methods (short-time Fourier transform and continuous wavelet transform) and estimation of fractal dimensions with advanced feature extraction approaches, including wavelet sub-band decomposition, Hilbert–Huang transform, peak analysis and entropy metrics. Subsequently, a Random Forest classifier is applied to each set of characteristics, and we report comparative accuracy results on a dataset comprising rail segments with joints, welds, or squats. Experimental findings reveal that the Hilbert–Huang transform features yield the highest accuracy (93.28%), while simpler features, such as peak counts, are less discriminative (46.93%). These results underscore the effectiveness of using multiple signal-decomposition strategies and advanced analytics to robustly detect and categorize surface defects for better rail-maintenance decisions
Flywheel Energy Storage System in Italian Regional Transport Railways: A Case Study
Full text linkIn this paper, we looked at the role of electromechanical storage in railway applications. A mathematical model of a running train was interfaced with real products on the electromechanical storage market supposed to be installed at the substation. Through this simulation, we gathered data on the recoverable energy of the system, its advantages, and its limitations. Various storage powers were run along variations in speed and gradient to paint a clearer picture of this application. Throughout these simulations, the energy savings were between 25% and 38%, saving up to 0.042 kWh/(seat km)
Directional Thermal Diffusivity of Additive Manufactured Thin Sheets
No full textThe thermal responses of two additive manufactured specimens (as built and heat treated) was analyzed for a steel magnetic plate as a case study. The analysis was based on the evidence that variations in the thermal properties of a material can be measured as a phase delay in material thermal diffusion. The specimens underwent active lock in laser thermography testing. The thermal signal post-processing was performed by a in-house Python code which automates the search for the laser beam centroid on the acqured thermal map. The directional diffusivity is then obtained. The results showed that after heat treatment, the slope of the phase diagram changed, indicating a change in thermal diffusivity and hence, thermal conductivity. The results highlight that the thermographic non destructive full field non contact approach can be used to evaluate the microstructure and thermal performance of magnetic steel additive manufactured components
Energy Community for Condominium Members
No full textThe paper aims to present the ways of realizing an energy community within a condominium with 55 apartments. The case study presents an example of an energy community that manages the production of renewable energy by placing photovoltaic systems on the roof for the common consumers of the condominium, but also proposals for an energy community in which a part of the individual consumption of each apartment is ensured. Also, the legislative, technical and financing barriers existing at the moment in the development of energy communities within condominiums were presented
Economic, Energy, and Environmental Analysis of PV with Battery Storage for Italian Households
Full text linkThe use of renewable energy sources is one way to decarbonize current energy consumption.
In this context, photovoltaic (PV) technology plays a direct fundamental role since it can convert sun
irradiance into electricity to be used for supplying electric loads for households. Despite the huge
availability of the solar resource, the intermittence of PV production may reduce its exploitation. This
problem can be solved by the introduction of storage systems, such as batteries, storing electricity
when PV overproduction occurs and acting as a source when PV generation is absent. Consequently,
increase in self-sufficiency and self-consumption can be expected in residential end users, paving the
way for more sustainable energy systems. In this paper, an economic, energy, and environmental
analysis of PV systems (without and with batteries) for the household is performed for the whole of
Italy, by means of a Geographical Information Systems (GIS) approach. A model to simulate energy
balance and to manage batteries is defined for households to assess the profitability of such systems
under an Italian regulation framework. Concerning results, indicators are provided at a national
scale using GIS tools to highlight areas where investments are more profitable, boosting the CO2
emission reductio
Optimization of Process Parameters for CuCrZr Alloy Manufactured by Electron Beam Powder Bed Fusion Technology
No full textThe CuCrZr alloys exhibit advantageous mechanical properties and high electrical conductivity which
make them promising for many applications in the electrical and aerospace engineering industries, e.g.
in the manufacture of vacuum electronics and fusion energy research. Unfortunately, these two
advantageous properties are in opposition to each other, i.e., the increase of hardness, is associated to
a decrease of electrical conductivity. Additive manufacturing technologies are good candidates to
balance these two aspects to achieve high performance parts. Powder-Bed-Fusion (PBF) techniques,
in fact, involve rapid heating and cooling rates which allow to obtain huge microstructural refinements,
thereby improving the mechanical properties without any significant loss in electrical conductivity. This
study concerns the process parameter optimization for CuCrZr alloys produced using Electron-Beam-
PBF technology using a trial-and-error approach. Material was characterized by porosity analysis,
tensile and electrical conductivity measurements. The effect of process parameters on microstructure
and densification behavior was also investigated
Study of Axial Flux Stator Structures in Additive Manufacturing Material and Soft Magnetic Composite
No full textFerromagnetic additive manufacturing materials show promising design solutions for electrical devices. On the other hand, their high magnetic performance is limited by significant eddy current losses. A possible solution to this issue involves modifying or laminating the magnetic core to reduce iron losses. In this context, several stator structures of an axial flux motor are examined through a dedicated model to evaluate 3D iron losses. The developed model is validated using experimental tests performed on a soft magnetic composite stator
Electromagnetic modelling of resistance spot welding system
No full textIn this study the modeling of a resistance spot welding (RSW) system is described. The numerical field solution based on the 3D finite formulation allows the calculation of the equivalent circuit parameters, with particular attention to the resistance of each part, and allow the estimation of external magnetic fields. Determining the equivalent circuit is crucial for the efficiency of the RSW, and assessing environmental field pollution is essential for protecting humans and equipment. Two different resistance spot welding operating conditions, AC and DC, are examined. To validate the proposed method, some experimental analyses are conducted on some parts of the RSW system and numerical and experimental results are compared
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