Materials and techniques of Art Nouveau architecture in Italy and Portugal: a first insight for an European route to consistent restoration

The results of the investigations on building materials and techniques of Casa Major Pessoa, a typical Art Nouveau construction in Aveiro (Portugal), and two coeval Art Nouveau buildings in Bologna (Italy) are presented as a methodological contribution to the restoration of this kind of buildings. This is the first step to ascertain the existence of a common thread between local materials, technologies and architecture in European countries at the same period. A holistic approach was adopted: materials were investigated along with architectural, structural and technological features, in order to achieve a first insight into the Art Nouveau architecture in Europe in particular for its consistent restoration without loss of historical memory

Waveform and Spectral Characteristics of Supraharmonic Unsymmetrical Conducted EMI of Switched-Mode Power Supplies

Switched-mode power supplies (SMPSs) are a relevant and widespread source of unsymmetrical conducted emissions, as they feed various electrical appliances and information technology equipment in office and residential contexts and, despite their low power rating, the limits are the same as those of larger equipment. Given the peculiar emission waveform (mixing impulsive components and switching components), assessment should be carried out with care to select parameters that guarantee both the detection of the maximum level of emissions and a high level of repeatability and reproducibility. A range of cases based on six different SMPS products was considered, exploring both time- and frequency-domain characteristics, and identifying the most relevant phenomena and advisable parameters choices. Typical behavior and suitable settings were exemplified with a range of measured emission records: the Fourier time window length and EMI receiver dwell time were considered, as well as the relevance of loading conditions to include in a comprehensive test program. Such records were made available in a linked dataset to allow for replication of the experiments and foster further findings and discussion

Electric and Magnetic Characterization of Materials

none3The knowledge of the electric and magnetic properties of materials over a broadband frequency range is an essential requirement for accurate modelling and design in several engineering applications. The interaction of incident electromagnetic fields with a material can be successfully investigated only when accurate information on the complex permittivity and magnetic permeability is attained. Regardless of the technique used for the measurement, the common challenge is the extraction of the complex relative permittivity and/or magnetic permeability from measured data by expressing the measured quantities as a function of these parameters. The inversion problem to be solved is thus affected by the mathematical model, i.e., the theoretical expressions that relate the electrical and/or magnetic parameters to the measured quantities. The inversion problem can be solved with deterministic or stochastic methods. The complex relative permittivity and magnetic permeability can be determined over the whole frequency range of interest or on a point-by-point basis (at individual frequency points).mixedL. Sandrolini; U. Reggiani; M. ArtioliL. Sandrolini; U. Reggiani; M. Artiol

Surface Photovoltage Spectroscopy and AFM Analysis of CIGSe Thin Film Solar Cells

The band gap, grain size, and topography of a Cu(In,Ga)Se2(CIGSe) thin film solar cell are analyzed using surface photovoltage spectroscopy (SPV) and atomic force microscopy (AFM) techniques. From the steep increase in SPV signal the band gap of the CIGSe absorber, In2S3and ZnO layers are extracted and found to be 1.1, 1.3 and 2.6 eV, respectively. Already below the band gap of ZnO layer, a slight SPV response at 1.40 eV photon energies is observed indicating the presence of deep donor states. The root mean square (rms) of the surface roughness is found to be 37.8 nm from AFM surface topography maps. The grain sizes are almost uniform and smaller than 1 μm

Materiales y tecnologías en la Arquitectura Modernista: casos de estudio de decoración de fachadas en Italia, Portugal y Polonia persiguiendo una restauración racional

The results of a diagnostic survey on the materials of representative Art Nouveau buildings in Italy, Portugal and Poland are here presented and compared, as a contribution to their understanding and, hence, to support compatible restoration. In particular, the facade decorations were investigated for the appraisal of their materials and technologies, often neglected in current maintenance/restoration works and so cancelled, leading to a severe loss in architectural image. The ongoing diagnostic campaign, in collaboration among different universities, is aimed to set up a database on materials and technologies of Art Nouveau facade decorations at a European scale, as a technical-scientific background for the highlighting of preservation guidelines

I materiali dell’ Arte Nova portoghese in Casa Major Pessoa ad Aveiro: caratterizzazione e confronto con edifici coevi in Bologna

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Experimental and Numerical Investigation of Termination Impedance Effects in Wireless Power Transfer via Metamaterial

This paper presents an investigation of the transmitted power in a wireless power transfer system that employs a metamaterial. Metamaterials are a good means to transfer power wirelessly, as they are composed of multiple inductively-coupled resonators. The system can be designed and matched simply through magneto-inductive wave theory, particularly when the receiver inductor is located at the end of the metamaterial line. However, the power distribution changes significantly in terms of transmitted power, efficiency and frequency if the receiver inductor slides along the line. In this paper, the power distribution and transfer efficiency are analysed, studying the effects of a termination impedance in the last cell of the metamaterial and improving the system performance for the resonant frequency and for any position of the receiver inductor. Furthermore, a numerical characterisation is presented in order to support experimental tests and to predict the performance of a metamaterial composed of spiral inductor cells with very good accuracy

Design procedure based on maximum efficiency for wireless power transfer battery chargers with lightweight vehicle assembly

This paper analyzes two different design procedures for a series-parallel compensated WPT battery charger, based on different definitions of the operating resonant frequency in the condition of maximum link efficiency. The behaviour of the voltage gain magnitude and the input impedance angle of the resulting WPT links is studied for different loads and coupling coefficients. The design algorithms are supported by analytical formulas derived from an exact circuit analysis of the WPT link, avoiding approximations as far as possible. To support the theoretical approach a case study is proposed, in which both design procedures are implemented considering specifications in line with the actual automotive standards. To conclude, a characterization of the efficiency in both cases is derived

Assessment of AC Corrosion Probability in Buried Pipelines with a FEM-Assisted Stochastic Approach

In this paper, a stochastic approach is combined with field theory and circuit methods to study how the geometrical and electrical properties of holidays (defects or pores in the insulating coating) in a metallic pipeline influence the probability of exceeding the current density limit for corrosion. Three-dimensional FEM simulations are conducted to assess the influence of the shape and electrical resistivity of the pore on the computed spread resistance value. The obtained results are then used to evaluate the probability of exceeding a given current density value for different sizes of pore and soil resistivities. Finally, a case of 50 Hz interference along a pipeline-transmission line routing is examined. The probabilistic approach presented in this paper allows the pipeline sections more subjected to the induced AC corrosion risk to be identified to be used as an auxiliary tool for adopting preventive protection countermeasures. Lastly, unlike most papers devoted to assessing electromagnetic interference on pipelines, the present work uses a probabilistic rather than a deterministic approach, representing its main novelty aspect

Salt-Induced Deterioration on FRP-Brick Masonry Bond

In the past decades, several studies have shown how fiber reinforced polymer (FRP) composites are an effective technique to strengthen unreinforced brick masonry structures. However, very little is known about their durability against environmental aggression such as salt attack and freeze-thaw cycles, or elevated moisture content. This paper presents an investigation on influence of salt attack on the stress transfer between the FRP composite and the masonry substrate. In fact, it is well known that, in certain conditions, soluble salts crystallize within the pores of materials, leading to crystallization pressures that may overcome their tensile strength. To investigate this effect, FRP-masonry joints were subjected to salt crystallization cycles according to a conditioning procedure designed by the authors. After conditioning, direct shear tests were conducted on the masonry joints to investigate the interfacial bond between the substrate and the composite. Materials characterization was carried out in order correlate the results of the direct shear tests with the salt distribution within the specimens. For comparison, direct shear tests were conducted on FRP-masonry joints that were not subjected to any cycle and therefore used as control