Metallic nanoscale particles attract a growing interest in several fields, thanks to their unique bonding characteristics; applications are appearing in the literature in the fields of, for example, ...sensor coatings and biochemical compound detection. However, the controlled fabrication of such nanopowders is often cumbersome, especially because their characterization is normally slow, involving procedures such as electron microscopy. On the other hand, microwave sensors based on near-field effects on materials are being developed with high sensitivity and show promising characteristics. In this paper, the authors show how a microwave sensor based on a Square Spiral Resonator can be used to characterize paraffin dispersions of nanoparticles conveniently and cost-effectively.
In this paper, we analyze the electrostatic charge distribution on arbitrarily shaped conductor surfaces. Following a perturbative approach, we derive an approximate analytical formulation of the ...problem. We start from the known case of a conducting ellipsoid, we adopt a deformed ellipsoidal coordinate system, and we search for the zero-order approximated solution of the problem. We also focus on arbitrary-shaped thin foils, showing that the charge density is divergent on their borders. We then define the applicability range of the proposed approach expressing the contour equation as the Fourier series. Finally, we present a detailed error analysis for several polygonal contours, comparing the analytical results with those obtained via a numerical analysis based on the Finite Element Methods (FEM).
In the recent years, the sustainable energy demand is growing among the civil and industrial sectors. However, the renewable sources present an aleatory behaviour, and the improvement of their ...reliable and secure employment have received great interest. In this framework, the energy storage devices can be used to smooth the market demand and to increase the control on the energy fluxes over transmission lines. To this aim, devices such as Li-ion batteries are widely used in several application scenarios, such as the transportation sector. Generally speaking, batteries are often classified as high-energy devices and their use for high-power applications is limited. Indeed, for the latter applications, other devices, such as supercapacitors or ultracapacitors, are usually employed. In the present work, the use of 3Ah 18650 Li-Ion batteries is investigated for high-power applications, and a performance analysis during pulsed discharge with current up to 50C is carried out. These experimental conditions are significantly beyond the manufacturer specifications; therefore, an accurate ageing estimation of the cell is required, and a novel internal resistance control method is proposed to monitor the state of health of the device.
Experimental analysis of overcharged Li-polymer batteries Ciorba, Serena; Marracci, Mirko; Antonetti, Claudia ...
Case studies in chemical and environmental engineering,
September 2020, 2020-09-00, 2020-09-01, Letnik:
2
Journal Article
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Since safety hazards can occur during the life of a Li-ion battery, understanding its behavior under abusive conditions is important for the development of a safe cell. In this work, overcharge tests ...on commercial Li-polymer cells were conducted in a climatic chamber, resulting in gas evolution. A comprehensive post-mortem analysis of the abused cells was carried out: the exhaust gases were identified by gas phase chromatography coupled with a thermal conductivity detector (micro-GC/TCD), then flammable and toxic species were detected; the cathode and anode materials were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS), while the electrolyte composition was studied by Fourier-transform infrared spectroscopy (FT-IR). Interestingly, the ambient temperature seemed to affect the degradation of the cell materials and hence the composition of the evolved gas.
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This paper presents and characterizes a measurement method for positioning of passive tags, by a drone equipped with a UHF-RFID reader. The method is based on a synthetic aperture radar approach and ...exploits the knowledge of the reader/drone trajectory, which is achieved with a differential Global Navigation Satellite System. Different sources of measurement uncertainty are analyzed by means of numerical simulations and experimental results. The method capabilities are discussed versus the length and shape of the reader trajectory. Finally, the proposed localization method is validated through an experimental analysis carried out with commercial RFID hardware and a microclass unmanned aerial vehicle.
This article presents a novel sensor-fusion method for indoor vehicle tracking. The phase of the signals backscattered by a set of Ultra High Frequency-Radio Frequency Identification (UHF-RFID) ...reference tags spread in the scenario is combined with the information acquired by on-board low-cost kinematic sensors. The RFID data are acquired by the on-board reader, during the relative motion of the vehicle with respect to the static reference tags, by resembling a synthetic-array approach, with an advantageous reduction of the reference-tag spatial density. In particular, such phase samples are combined with the kinematic data collected by odometers, through a sensor-fusion approach. The method capability is investigated through a numerical analysis that accounts for the main system parameters. Then, the tracking capability is demonstrated through a measurement campaign in a laboratory test set with a UHF-RFID robot prototype equipped with commercial encoders. Experimental results show an average localization error of centimeter order in the estimation of medium-length trajectories by employing only two reference tags in a relatively small area. The proposed method does not need for any calibration procedure and can be implemented by commercial off-the-shelf (COTS) hardware.
We propose a novel approach to evaluate the open circuit potential and the entropic heat coefficient vs. the state of charge curve via charge/discharge tests run at different temperatures. In ...particular, we drive the battery cell with an extremely small current thus moving along with different state of charges in a quasi-static condition. We present a model to properly define the measurand and we discuss the assumption made to the method application. Finally, we analyse the method accuracy and its reliability through a comparison with other techniques commonly employed in the literature to this purpose.
Human walking analysis in a random walk framework Raglianti, Marina; Bologna, Mauro; Tellini, Bernardo
Measurement : journal of the International Measurement Confederation,
October 2023, 2023-10-00, Letnik:
220
Journal Article
Recenzirano
In this paper, we analyze the human walk movement via a combined deterministic-stochastic model built on top of a random walk framework. By adopting the Laban Effort subcategories to investigate ...different movement classes, we discuss how stochastic and deterministic forces combine to determine the act of moving and relate the stochastic component to the times at which we can observe a movement change. Major elements of our study are the analysis of random times when there is a walk movement change, the construction of a distribution (waiting time distribution), and the implementation of a dichotomic stochastic force. In particular, we report the observed walk trajectories obtained via an experimental analysis performed in collaboration with a group of volunteers to show, to some degree, the relationship between their walks and the measured relevant random times. Finally, we present our model results via simulated trajectories of a virtual character.
•Analysis of human walk movement within a continuous time random walk framework.•Experimental analysis of walk trajectories simulating the Laban Effort subcategories•Random time interval and walk trajectory analysis within the Laban Effort framework.
In this paper, we present a new model of dendrite growth in battery cells through theoretical and numerical analysis. We use a statistical model based on the competition between a deterministic ...electric field and a stochastic force, which both drive the movement of the particles inside the battery cell. The simulation of the dendrite growth is modeled via Diffusion Limited Aggregation. As a major aspect, we point out the key role played by the intense electric field close to the edges of the electrodes, which statistically drives the particles along the electric field lines.
•Electric field distribution in a battery cell through a finite capacitor model.•Statistical approach combining deterministic and stochastic forces.•Simulation of dendrite growth via Diffusion Limited Aggregation model.
This paper presents a measurement method for tagged item classification in radio frequency identification (RFID)-based smart drawers. Specifically, the amplitude of the signal backscattered by the ...UHF-RFID passive tags attached to the items inside the drawer is used to identify at which of an assigned set of drawer subregions each detected tag belongs to. The received signal strength indicator (RSSI) may be acquired by almost any UHF-RFID commercial reader chipset compatible with the Electronic Product Code (EPC) Class1 Gen2 protocol. The RSSI model in terms of the position of the tag inside the drawer is introduced, and its selective properties are discussed through both numerical data and measurements. The cases of a single reader antenna measuring during natural opening/closing operations as well as of multiple reader antennas measuring when the drawer is static are investigated. The measurement method performance is shown through an experimental analysis in a realistic scenario, where the RSSI values are collected by using commercial UHF-RFID hardware components, and then used as the feature vector of the classification algorithm. As an example, two different classifiers are used to map each detected tag to one of the regions that the drawer is subdivided into. The classification performance of the method based on a single antenna exploiting the drawer natural sliding movements is comparable to that achievable with multiple reader antennas, while representing a cost-effective and easy-to-implement practical solution.
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