A Voltage Calibration Chain for Meters Used in Measurements of EV Inductive Power Charging

The inductive charging of electric vehicles requires specific measurement and calibration systems. In fact, the measurement of power on board involves DC signals, which are superimposed to a significant AC ripple up to or over 150 kHz, depending on the type of charging system. A calibration method that makes use of a phantom power, based on two independent but synchronized circuits, is considered, simulating the charging voltage and current. This paper describes in detail a solution in the realization of the voltage calibration chain, based on the use of a DC voltage calibrator, an injector and a voltage divider.Comment: 2 pages, Conference on Precision Electromagnetic Measurements (CPEM 2018), Paris

A substructure analysis of the A3558 cluster complex

The "algorithm driven by the density estimate for the identification of clusters" (DEDICA, Pisani 1993, 1996) is applied to the A3558 cluster complex in order to find substructures. This complex, located at the center of the Shapley Concentration supercluster, is a chain formed by the ACO clusters A3556, A3558 and A3562 and the two poor clusters SC 1327-312 and SC 1329-313. We find a large number of clumps, indicating that strong dynamical processes are active. In particular, it is necessary to use a fully three-dimensional sample(i.e. using the galaxy velocity as third coordinate) in order to recover also the clumps superimposed along the line of sight. Even if a great number of detected substructures were already found in a previous analysis (Bardelli et al. 1998), this method is more efficient and faster when compared with the use of a wide battery of tests and permits the direct estimate of the detection significance. Almost all subclusters previously detected by the wavelet analyses found in the literature are recognized by DEDICA. On the basis of the substructure analysis, we also briefly discuss the origin of the A3558 complex by comparing two hypotheses: 1) the structure is a cluster-cluster collision seen just after the first core-core encounter; 2) this complex is the result of a series of incoherent group-group and cluster-group mergings, focused in that region by the presence of the surrounding supercluster. We studied the fraction of blue galaxies in the detected substructures and found that the bluest groups reside between A3562 and A3558, i.e. in the expected position in the scenario of the cluster-cluster collision.Comment: 10 pages with 12 encapsulated figures; MNRAS in pres

Structural health monitoring of an onshore steel wind turbine

The study presents the development of a structural monitoring system installed in a 45-m-high steel wind tower located in Italy. The installed monitoring system was composed by 16 strain gauges placed in the tower wall, in a pattern of four Wheatstone bridges at 45°, together with thermal couples, at 21 m from the ground (half-height of the tower). Moreover, several accelerometers were placed along the tower height (with one of them located next to the strain gauges). The wind velocity and directions were obtained directly from the turbine own monitoring system. Such a monitoring system was designed because, due to the decrement of the total height from the original design, the tower sufers from resonance problems. In fact, the investigated tower was originally designed with 65 m of height but then, to comply with local regulations, the height was decreased to the actual size. Therefore, to allow safe operation and avoid excessive fatigue due to the increased displacements, the velocity of the rotor has been manually limited causing an important reduction in the energy production. The results of the study show the importance of monitoring the resonance issue. The diferences between the damage indexes obtained with two diferent working conditions are discussed: tower working with limited operational capacity and tower working at its maximum capacity (in resonance)

Gram-negative bacterial toe web intertrigo

Gram-negative infection of the toe web space is less frequent than dermatophytes and yeasts, but it is more challenging, especially with the involvement of Pseudomonas aeruginosa in relation to antibiotic resistance and the increased risk of potentially lethal complications. Many conditions, other than infections, might initially present with the same clinical features, recognising the common initial damage (intertrigo), due to skin-on-skin rubbing in a moist environment with air entrapment, which is typical of interdigital spaces. Conditions such as contact eczema, atopic dermatitis, and inverse psoriasis, frequently predispose to, and are maintained by, the intertrigo, triggering a vicious circle. The dermatologist is in a lead position to address the correct assessment and management. A careful screening for predisposing factors is necessary: overweight, diabetic, but also athletes or people attending swimming pools, gyms, public showers/dressing rooms, and thermal baths are also at an increased risk of intertrigo of the toe web spaces. Occupational activities other than recreational might be relevant, such as the use of safety shoes or working in wet warm conditions. Incongruous therapy for tinea pedis or contact dermatitis, frequently auto-prescribed, might be among promoting factors altering the microbial ecosystem balance. The aim of this review is to evaluate the main epidemiologic and clinical features of Gram-negative bacteria intertrigo, the role of promoting factors, and the measures taken to treat and prevent this disorder. Appropriate treatment and patient education are crucial to prevent further infection and relapses

Seismic vulnerability of Santa Maria Novella Basilica in Florence

This paper presents the evaluation of the seismic vulnerability of Santa Maria Novella Basilica in Florence. Santa Maria Novella is one of the most important historical churches in Italy and, for this reason, different studies on the structural behavior of this monument were conducted during the last decades. Particularly, this work is focused on the dynamic behavior of the church. Mechanical properties of masonries were determined through "in situ" and laboratory tests, according to the National Italian Code (Norme Tecniche per le Costruzioni, 2018). An eigenvalue analysis on a finite element model of the Basilica was performed to obtain the fundamental vibration mode shapes.Finally, to evaluate the seismic risk index in terms of ratio between the minimum peak ground acceleration which leads to the first collapse of a structural element and the design peak ground acceleration, a response spectrum analysis was carried out to evaluate the stress fields in both columns and walls

Experimental investigation on a Fe-Ga close yoke vibrational harvester by matching magnetic and mechanical biases

Abstract The output power generated by a vibrational magnetostrictive energy harvester depends on several parameters, some of them linked to the mechanical source, as vibration amplitude and frequency, others related to design quantities, like mechanical preload, magnetic bias, coil turns and load impedance. Complex models have been developed in literature to reproduce the behavior of these devices. However, for output variables such as power and voltage, one moves in a space of many variables and it is not trivial to reconstruct an overall behavior of the device. The aim of this paper is to provide a wide picture concerning the device behavior investigating experimentally the output power and voltage as a function of the mechanical and especially magnetic bias, varying the amplitude and frequency of the driving vibration. A galfenol rod (Fe 81 Ga 19 ) sample inserted in a three-legged magnetizer is utilized to vary the magnetic bias and to provide the flux closure to the sample, while a dynamic test machine provides both the mechanical bias and the driving vibration at different frequencies up to 100 Hz. The paper analysis has highlighted that the output power and voltage depend on the magnetic bias according to an exponentially modified Gaussian distribution. Keeping constant the other parameters and varying the mechanical bias, a family of modified Gaussian distributions is obtained. Moreover, fixing the electric load, the amplitude and frequency of the vibration, the couple of values "magnetic bias – mechanical preload" corresponding to the maximum output power of the device depicts a linear behavior. The results here obtained point out that it is possible to simplify the design of magnetostrictive energy harvesters and to obtain high output power even with permanent magnets providing a relatively small coercive field. The results have been confirmed by using two yokes equipped with permanent magnets on the external columns. The maximum output average power obtained with permanent magnets has been 796 mW equal to 6.5 mW/cm 3 with a sinusoidal vibration amplitude of 40 MPa at 100 Hz

Two-bands effect on the superconducting fluctuating diamagnetism in MgB&#8322

The field dependence of the magnetization above the transition temperature Tc in MgB₂ is shown to evidence a diamagnetic contribution consistent with superconducting fluctuations reflecting both the σ and π bands. In particular, the upturn field Hup in the magnetization curve, related to the incipient effect of the magnetic field in quenching the fluctuating pairs, displays a double structure, in correspondence to two correlation lengths. The experimental findings are satisfactorily described by the extension to the diamagnetism of a recent theory for paraconductivity, in the framework of a zero-dimensional model for the fluctuating superconducting droplets above Tc