Search

Health assessment and preventive maintenance of structures are mandatory to predict injuries and to schedule required interventions, especially in seismic areas. Structural health monitoring aims to provide a robust and effective approach to obtaining valuable information on structural conditions of buildings and civil infrastructures, in conjunction with methodologies for the identification and, sometimes, localization of potential risks. In this paper a low-cost solution for structural health monitoring is proposed, exploiting a customized embedded system for the acquisition and storing of measurement signals. Experimental surveys for the assessment of the sensing node have also been performed. The obtained results confirmed the expected performances, especially in terms of resolution in acceleration and tilt measurement, which are 0.55 mg and 0.020°, respectively. Moreover, we used a dedicated algorithm for the classification of recorded signals in the following three classes: noise floor (being mainly related to intrinsic noise of the sensing system), exogenous sources (not correlated to the dynamic behavior of the structure), and structural responses (the response of the structure to external stimuli, such as seismic events, artificially forced and/or environmental solicitations). The latter is of main interest for the investigation of structures' health, while other signals need to be recognized and filtered out. The algorithm, which has been tested against real data, demonstrates relevant features in performing the above-mentioned classification task. [ABSTRACT FROM AUTHOR]

With the support of public authorities and research institutions, volcanic ash fallout and its impact on the safety of people, infrastructure and services are addressed with the aim of defining protocols and instruments for the reliable and effective handling of related emergencies. Most of the solutions proposed in the literature on ash fallout monitoring suffer from high cost and are demanding in terms of installation and maintenance. The approach suggested in this work is based on the use of a low-cost vision embedded system and a dedicated algorithm which automatically processes acquired frames of ground-deposited volcanic ash in order to estimate the main geometric properties of each particle identified in the work area. A complete characterization of the system is presented, along with a robustness analysis of particle shapes, their orientation and their position in the inspected frame. An accuracy of ±40.2 µm (with a 3σ limit) and a resolution of 32.9 µm (in the worst case), over a framed area of 130 mm by 100 mm, were estimated; these values would fulfill the objectives of the application. [ABSTRACT FROM AUTHOR]

Assistive Technology helps to assess the daily living and safety of frail people, with particular regards to the detection and prevention of falls. In this paper, a comparison is provided among different strategies to analyze postural sway, with the aim of detecting unstable postural status in standing condition as precursors of potential falls. Three approaches are considered: (i) a time-based features threshold algorithm, (ii) a time-based features Neuro-Fuzzy inference system, and (iii) a Neuro-Fuzzy inference fed by Discrete-Wavelet-Transform-based features. The analysis was performed across a wide dataset and exploited performance indexes aimed at assessing the accuracy and the reliability of predictions provided by the above-mentioned strategies. The results obtained demonstrate valuable performances of the three considered strategies in correctly distinguishing among stable and unstable postural status. However, the analysis of robustness against noisy data highlights better performance of Neuro-Fuzzy inference systems with respect to the threshold-based algorithm. [ABSTRACT FROM AUTHOR]

The problem of estimating the indoor position of a person or an object, also known as indoor localization, has gained a lot of interest in the last decades. Actually, this feature would be valuable in many application contexts, from logistics to robotic and Assistive Technology. Different solutions have been proposed in the literature, exploiting a wide range of approaches. This paper aims to provide a brief review of the state-of-the-art approaches in the field, as well as to present the RESIMA case study. The latter exploits an ultrasound-based indoor localization system and a User–Environment Interaction functionality, which allows for performing the continuous estimation of the distance between the end-user and objects in the environment. The latter is valuable to provide the end-user with efficient assistance during the environment exploitation. The main focus of this work is related to the overall description of the system architecture, the trilateration algorithm adopted for the sake of user localization and the estimation of the delay time produced by user-distance computation under different operating conditions. [ABSTRACT FROM AUTHOR]

Recently, there has been an upsurge in efforts dedicated to developing low-cost flexible electronics by exploiting innovative materials and direct printing technologies. This interest is motivated by the need for low-cost mass-production, shapeable, and disposable devices, and the rapid prototyping of electronics and sensors. This review, following a short overview of main printing processes, reports examples of the development of flexible transducers through low-cost inkjet printing technology. [ABSTRACT FROM AUTHOR]

This paper analyses the application o f satellite technologies to the railway sector, where such technologies are playing an increasingly important role for signaling, communications, diagnostics and security. The aim o f this work has been to examine and evaluate GPS satellite observations in combination with data from a RTK receiver obtained from the projects 3InSata> and ERSATI2>, a trial and validation test site has been placed in Sardinia, it is based on the combination o f the ERTMS / ETCS and the satellite tracking technology, integrated with TLC (i.e. GSM-3G, Tetra, Satellite) systems using the IP protocol. These projects have been recently set up by Ansaldo STS and Rete Ferroviaria Italiana (RFI) and the University o f Catania in order to create a trial and validation site in Sardinia - that is located along the railway track ‘Cagliari-San Gavino’ - for assessing the consequences o f satellite-based technologies on the railway infrastructures and systems. The acceptability o f the work has been supported by the fact that the average precision position per train trip was always lower than 3 meters in line with railway standards(3). [ABSTRACT FROM AUTHOR]

Accessibility and autonomy are fundamental needs for people with visual impairments wishing to enjoy their rights as citizens and to access buildings, premises, and other facilities. Dealing with the possibility of autonomously performing activities of daily living, two main aspects are mandatory: autonomous mobility and living independently. In particular, dealing with autonomous accessibility is strictly related to the possibility to perceive the environment and to gain a realistic and intuitive awareness of ongoing events and hazards. In order to promote living independently, caregivers (whether relatives or assistive services) need to be aware of the user's physical surroundings. The literature is rich in attempts to provide technical solutions to improve quality of life and autonomy for frail people, particularly with regard to the visually impaired. This review summarizes "state of the art" electronic aids for the visually impaired, and aims to to highlight the benefits and drawbacks of these aids. [ABSTRACT FROM AUTHOR]

Accessibility and autonomy are fundamental needs for people with visual impairments wishing to enjoy their rights as citizens and to access buildings, premises, and other facilities. Dealing with the possibility of autonomously performing activities of daily living, two main aspects are mandatory: autonomous mobility and living independently. In particular, dealing with autonomous accessibility is strictly related to the possibility to perceive the environment and to gain a realistic and intuitive awareness of ongoing events and hazards. In order to promote living independently, caregivers (whether relatives or assistive services) need to be aware of the user's physical surroundings. The literature is rich in attempts to provide technical solutions to improve quality of life and autonomy for frail people, particularly with regard to the visually impaired. This review summarizes "state of the art" electronic aids for the visually impaired, and aims to to highlight the benefits and drawbacks of these aids. [ABSTRACT FROM AUTHOR]

Abstract: The ash fall-out following explosion activity of volcanoes represents a relevant factor of risk for people and facilities in the area near the volcano and a serious hazard for air traffic civil and otherwise [1] mainly when airports are close to active volcanoes. This is the case of the international Fontanarossa Airport in Catania close to Mount Etna. Researchers at DIEEI of the University of Catania are facing the challenge of developing a low-cost smart multisensor system for the monitoring of ash fall-out phenomena by measuring ash presence, average granulometry and ash flow rate. Moreover, the system must discriminate volcanic ash from others sediments such as dust, sand or soil. This paper is particularly focused on the methodology adopted for ash granulometry detection. The main idea is to use a piezoelectric transducer to convert ash impacts in electrical signals which should provide information about ash granulometry. Experimental investigations have been performed using volcanic ash with three different granulometries (big, medium and small) ranging from 2mm to 0.2mm. Experimental results are presented together with the methodology developed to classify ash granulometry. [Copyright &y& Elsevier]

In this paper, a novel device for sensing perturbations imposed to liquid media contained in a disposable housing is addressed. The device consists of a glass beaker filled with deionized water surrounding a small volume of ferrofluid; a permanent magnet is used to fix the position of the ferrofluidic mass in a compliant position and to generate spikes due to the Rosensweig effect. The effect of external stimuli on the beaker can be estimated by measuring the perturbation produced on the ferrofluidic mass. The latter strategy allows reducing drawbacks related to static friction of conventional inertial devices. The ferrofluid perturbations are monitored by two external planar coils in a differential configuration. The main features of the proposed strategy are structural decoupling between the electric read-out system and beaker housing, which allows both implementing noninvasive measurement in liquid media and making the architecture partially disposable, of low cost, and suitable for real applications. [ABSTRACT FROM AUTHOR]

In this paper, an innovative inclinometer exploiting ferrofluids is presented. The device consists of a glass pipe filled with deionized water and a drop of ferrofluid, a coil generating a retaining force on the ferrofluidic drop, a couple of sensing coils detecting the ferrofluidic mass position, and two exciter coils moving the ferrofluidic drop back and forth inside the water at the resonance frequency of the whole system. The device exhibits an intrinsic robustness against inertial shocks. The resonant operation mode represents the main novelty with respect to previous realizations of the ferrofluidic inclinometer presented by the authors. This strategy allows for improving the performances of the inclinometer also in terms of mechanical sensitivity. This paper will focus on the design and experimental characterization of the resonant inclinometer, showing improvements achieved by the resonant configuration with respect to the previous "static implementation" without the exciter coils. [ABSTRACT FROM AUTHOR]

A new sensor for quasistatic electric field (E-field) measurements based on a ferroelectric capacitor (which acts as a nonlinear active dynamic element) is discussed in this paper. The device was theoretically modeled and experimentally characterized, and the data that were gathered were used to refine the model parameters. The E-field sensing strategy is based on the exploitation of a mechanism to convert the external target E-field into a perturbation on the polarization state of a ferroelectric material: a detailed analytical description of this process is given together with its experimental validation. Optimal results have been obtained with a driving (i.e., reference) signal of 10 V at 100 Hz, which was used to polarize the device. The noise floor of the device has been evaluated through an analysis of the power spectral density, which yields a value of 0.4 (V/m)/Hz1/2. The hysteretic capacitor in this paper is the cornerstone of an innovative system for detecting weak E-fields (assumed to be dc throughout this paper, although it can also be applied to detect time-periodic E-fields) through the exploitation of the nonlinear behavior of a coupled oscillator system wherein the active (nonlinear) elements are the ferroelectric capacitors. Our results cover the basic building blocks that were necessary for the optimal realization of this coupled circuit. [ABSTRACT FROM AUTHOR]

Abstract: In this paper a novel ferrofluidic pump is proposed. The architecture is free of mechanical moving parts and is based on a single drop of ferrofluid as the active mass, thus improving the device reliability. This solution allows for a non-invasive implementation of a pumping mechanism (or a flow regulation) into preexistent non-metallic pipes (such as veins in a visionary context, etc.), without the real need of breaking the pipe: to implement the pumping mechanism, a single drop of ferrofluid is injected into the fluid inside the pipe while an “all-in-one” driving system is externally clamped in the pipe. [Copyright &y& Elsevier]

The use of magnetic fluids in transducers is of great interest due to the possibility of implementing highly reliable and reconfigurable sensors and actuators. Examples of ferrofluidic transducers are available in several contexts from the detection of inertial quantities to assorted bioapplications. This paper ad- dresses a novel architecture implementing a ferrofluidic pump intended for several purposes, including fluid control in bioapplications. The proposed architecture can be used to realize discrete and integrated pumps. The strategies that led to the implementation of the device are highlighted, along with theoretical considerations. The real prototype developed and the setup adopted for its characterization are also presented, along with experiments aimed at estimating the performance of the device. [ABSTRACT FROM AUTHOR]

The development of electronic sensing devices for the visually impaired requires knowledge of the needs and abilities of this class of people. This paper presents a rough analysis that can be used to properly define the criteria to be adopted for the design of such devices. In particular, attention will be focused on clear-path indicators, highlighting their role in orientation and mobility tasks. A new device belonging to this class is presented. The detector is based on a multisensor strategy and adopts smart signal processing to provide the user with suitable information about the position of objects hindering his or her path. Experimental trials demonstrate the efficiency of the device developed. [ABSTRACT FROM AUTHOR]

Ferroelectrics are suitable for the realization of sensors because their characteristics depend on modifying quantities such as temperature, electric fields, and pressure. The dependence of the dielectric and pyroelectric constant of ferroelectric materials on temperature is large and close to the Curie temperature, and this behavior can be exploited for the realization of capacitive sensors with high sensitivity in such a range of temperature. In this paper, a convenient solution for the investigation of the dielectric and pyroelectric coefficients of a ferroelectric device is discussed, along with a characterization tool developed to measure them. The architecture adopted was developed to study the aforementioned material properties up to the Curie temperature. A general- purpose data acquisition card and instruments usually available in research and educational laboratories were used, thus guaranteeing the low-cost feature, easy reproducibility, and flexibility. [ABSTRACT FROM AUTHOR]

Residence times difference (RTD) fluxgates are very simple magnetic sensors that have low onboard power requirements and an intrinsic digital (i.e., event based) form of the readout signal. These features make this class of devices competitive with the traditional second-harmonic fluxgate, which usually requires a higher power budget. Moreover, these detectors are characterized by high sensitivity and a suitably low resolution and noise floor when compared to the devices that are already on the market. Our work on RTD fluxgates has been widely presented in previous papers. In this paper, an overview of this work, which deals with the development of models, prototypes, and readout electronics and the effects of electric and magnetic noise, is presented, together with some noticeable forward steps regarding the characterization of the prototype, which is developed in the standard printed circuit board (PCB) technology, and with a preliminary discussion on possible solutions to improve the performance of the device with an emphasis on the resolution. [ABSTRACT FROM PUBLISHER]

Hysteresis is a common phenomenon in nonlinear systems. Piezoelectric bimorphs show hysteretic behavior when operating as actuators. Tools that produce the characterization of these devices are available; they use high-cost setups that measure deformations with resolutions on the order of nanometers. In this paper, a new low-cost experimental setup that uses coupled infrared detectors to investigate the behavior of piezoelectric actuators is discussed. The tool, providing deformation measurements with a resolution on the order of 10 , is intended to produce a rough estimation of the device behavior and is of interest for research and educational purposes. Low cost, easy reproducibility in research and educational laboratories, a contactless measurement strategy, an inset calibration facility, and a suitable user interface are the main features of the tool developed. Notes on the uncertainty introduced by the tool when estimating bimorph deformations are given. Moreover, a case study that concerns the characterization of a piezoelectric bimorph actuator is discussed to illustrate the performance of the system developed in a real case. [ABSTRACT FROM PUBLISHER]

Continuously running gravimeters are usually adopted to overcome the drawbacks of discrete measurements that are used to monitor gravity changes in volcanic areas (i.e., inaccessibility during wintertime). Exogenous environmental parameters, however, usually affect the performance of these devices, and suitable analytical methodologies are adopted to compensate for these effects. This paper aims to demonstrate the features of the nonlinear compensation strategy that was introduced by the author in the previous works when a real-time reduction of the gravimeter output for the effect of meteorological parameters has to be performed. Moreover, a microcontroller-based electronics that implements such real-time compensation strategy is presented. [ABSTRACT FROM AUTHOR]

Inertial transducers based on the use of ferrofluids as inertial mass can be of great interest due to their peculiarities and due to the advantages that they show when compared to traditional devices. Ferrofluids are special solutions of magnetic particles in a carrier liquid whose density and other physical features can be controlled by an external magnetic field. In this paper, the development of a ferrofluidic inclinometer, which exhibits a tunable operating range and a valuable metrological feature and an intrinsic robustness against inertial shocks, is presented. The device consists of one excitation coil and two sensing coils wound around a glass pipe where a drop of ferrofluid is contained in a water environment. The magnetic force, which is induced by the excitation coil, attracts the ferrofluidic mass in a position that depends on the device inclination. The voltage at the output of the two sensing coils is related to the ferrofluidic mass displacement and thus reflects the tilt to be measured. Analytical models, simulations, and experimental results are presented to demonstrate the suitability of the proposed approach. [ABSTRACT FROM AUTHOR]

Abstract: The experience of several authors has shown that continuous measurements of the gravity field, accomplished through spring devices, are strongly affected by changes of the ambient temperature. The apparent, temperature-driven, gravity changes can be up to one order of magnitude higher than the expected changes of the gravity field. Since these effects are frequency-dependent and instrument-related, they must be removed through non-linear techniques and in a case-by-case fashion. Past studies have demonstrated the effectiveness of a Neuro-Fuzzy algorithm as a tool to reduce continuous gravity sequences for the effect of external temperature changes. In the present work, an upgraded version of this previously employed algorithm is tested against the signal from a gravimeter, which was installed in two different sites over consecutive 96-day and 163-day periods. The better performance of the new algorithm with respect to the previous one is proven. Besides, inferences about the site and/or seasonal dependence of the model structure are reported. [Copyright &y& Elsevier]

High-performance models are required during the design (phase) of sensing devices in order to take their physical behavior into account and to include these models in calculations and simulations aimed at optimizing the performance of devices in fixed operating conditions. In this paper, the problem of model fitting for ferroelectric devices is addressed; in particular, a model of the behavior of a ferroelectric capacitor is accomplished. The static behavior of such devices is investigated, and an experimental setup for both characterization and model estimation is proposed. The model obtained is assessed, and the uncertainty introduced by the measurement system is estimated. [ABSTRACT FROM AUTHOR]

In recent years, great effort has been dedicated to understanding the phenomena connected with volcanic activities. In particular, the behavior of flowing lava during a big eruption is of great interest in managing emergency activities. The very first parameters to be taken into account in studying the path of the lava flow are those defining the crust properties, which are highly dependent on the cooling process. In this paper, the improvement of a multisensorial measurement system already presented by the authors is proposed, which allows the estimation of the emittance value at higher resolution than the previous architecture. This feature permits. the study of the heat transfer process in the boundary regions of the lava flow during crust formation. This is an important task for experts in order to predict the behavior of the lava flow, with emittance strictly correlated to the heat transfer process and, hence, to the crust formation. [ABSTRACT FROM AUTHOR]

Ferroelectric materials show the hysteresis effect; in particular, with a zero field there are two equally stable states of polarization ±Pr allowing for the design of a binary-state device in the form of a ferroetectric capacitor (metal ferroelectric-metal) that can be reversed electrically. The characterization of ferroelectric devices consists of determining the hysteresis behavior and ±Pr quantities. Industrial equipment for producing this kind of characterization is expensive, and complex systems are needed for specific tasks. This paper proposes a low-cost tool for addressing the properties of ferroelectric devices, which is useful for qualitative investigation in research laboratories. [ABSTRACT FROM AUTHOR]

In the field of measurement nonlinear behavior is typical of a large set of sensors (mechanical, electrical, pneumatic, and so on). In several devices, SQUID and piezoelectric sensors being very well-known examples, the nonlinearity is strictly correlated to the hysteresis phenomenon, which can be described by introducing the quartic double well (QDW) potential in the system model. The analysis addresses the influence of potential characteristics on the performance of hysteretic measuring devices. A Brownian system with a QDW potential is used as a general prototype of hysteretic phenomena. This paper applies to the general class of hysteretic devices forced with low-amplitude signals and gives suitable out lines for the design of several measuring devices. [ABSTRACT FROM AUTHOR]

Gravity measurements are utilized at active volcanoes to detect mass changes linked to magma transfer processes and thus to recognize forerunners to paroxysmal volcanic events. Continuous gravity measurements are now increasingly performed at sites very close to active craters, where there is the greatest chance to detect meaningful gravity changes. Unfortunately, especially when used against the adverse environmental conditions usually encountered at such places, gravimeters have been proved to be affected by meteorological parameters, mainly by changes in the atmospheric temperature. The pseudo-signal generated by these perturbations is often stronger than the signal generated by actual changes in the gravity field. Thus, the implementation of well-performing algorithms for reducing the gravity signal for the effect of meteorological parameters is vital to obtain sequences useful from the volcano surveillance standpoint. In the present paper, a Neuro-Fuzzy algorithm, which was already proved to accomplish the required task satisfactorily, is tested over a data set from three gravimeters which worked continuously for about 50 days at a site far away from active zones, where changes due to actual fluctuation of the gravity field are expected to be within a few microgal.After accomplishing the reduction of the gravity series, residuals are within about 15 μGal peak-to-peak, thus confirming the capabilities of the Neuro-Fuzzy algorithm under test of performing the required task satisfactorily. [Copyright &y& Elsevier]

This paper presents the development and uncertainty characterization of a system for the direct measurement of heat transfer in cooling lava. The system continuously measures the parameters involved in the cooling process and, particularly, in the formation of the crust. The aim is to allow the future development of a physical model of the cooling process itself. In order to realize a system that will be effective in such a hostile environment, the principles on which the instruments for radiation thermometry are based have been thoroughly investigated. A virtual instrument has been developed, interfacing the measuring system and the user, processing the incoming data, and producing an estimate of the uncertainty of the measurement chain. The various sources of uncertainty have been taken into account to produce an accurate estimate of the uncertainty associated with the measured data. The results of experimental tests are presented. [ABSTRACT FROM AUTHOR]

Real laboratory experiments can help students to gain a better understanding of theoretical problems. Great efforts are needed, however, to improve the quality of laboratory sessions, and a large number of tutors are usually required. Moreover, students may lose time because of hardware failure or an inefficient experimental setup. Several educational tools (based on virtual instruments) have been developed allowing for optimized time scheduling and remote access to laboratory sessions. Drawbacks related to hardware failure have not, however, been seriously addressed. This paper proposes an educational tool made up of a user-friendly interface controlling experimental boards. It basically consists of an array of optical sensing devices connected to suitable conditioning circuits, which are interfaced to a virtual instrument by means of a data acquisition system. To solve the previously mentioned drawbacks, a solution based on both pre-cabled hardware and PC-based measurement stations has been adopted. Moreover, the ability to configure self-educational tasks optimizes time scheduling for students during laboratory activities. The proposed system allows students to improve their knowledge in the field of optical sensing devices, virtual instrumentation, data acquisition systems, and signal processing. The paper describes an application of the tool as a simple system for surface recognition. This application is one of the laboratory tasks performed in measurement classes during this engineering course at the University of Catania, Catania, Italy. [ABSTRACT FROM AUTHOR]

Volcanic ash fall-out represents a serious hazard for air and road traffic. The forecasting models used to predict its time–space evolution require information about the core characteristics of volcanic particles, such as their granulometry. Typically, such information is gained by the spot direct observation of the ash collected at the ground or by using expensive instrumentation. In this paper, a vision-based methodology aimed at the estimation of ash granulometry is presented. A dedicated image processing paradigm was developed and implemented in LabVIEW™. The methodology was validated experimentally using digital reference images resembling different operating conditions. The outcome of the assessment procedure was very encouraging, showing an accuracy of the image processing algorithm of 1.76%. [ABSTRACT FROM AUTHOR]

The development of low-cost mass sensors is of unique interest for the scientific community due to the wide range of fields requiring these kind of devices. In this paper, a full inkjet-printed mass sensor is proposed. The device is based on a PolyEthylene Terephthalate (PET) cantilever beam (operating in its first natural frequency) where a strain-sensor and a planar coil have been realized by a low-cost InkJet Printing technology to implement the sensing and actuation strategies, respectively. The frequency readout strategy of the sensor presents several advantages, such as the intrinsic robustness against instabilities of the strain sensor, the residual stress of the cantilever beam, the target mass material, and the distance between the permanent magnet and the actuation coil (which changes as a function of the target mass values). However, the frictionless actuation mode represents another shortcoming of the sensor. The paper describes the sensor design, realization, and characterization while investigating its expected behavior by exploiting dedicate models. The working span of the device is 0–0.36 g while its resolution is in the order of 0.001 g, thus addressing a wide range of potential applications requiring very accurate mass measurements within a narrow operating range. [ABSTRACT FROM AUTHOR]

The Internet of Things paradigm envisions the interoperation among objects, people, and their surrounding environment. In the last decade, the spread of IoT-based solutions has been supported in various domains and scenarios by academia, industry, and standards-setting organizations. The wide variety of applications and the need for a higher level of autonomy and interaction with the environment have recently led to the rise of the Internet of Robotic Things (IoRT), where smart objects become autonomous robotic systems. As mentioned in the recent literature, many of the proposed solutions in the IoT field have to tackle similar challenges regarding the management of resources, interoperation among objects, and interaction with users and the environment. Given that, the concept of the IoT pattern has recently been introduced. In software engineering, a pattern is defined as a general solution that can be applied to a class of common problems. It is a template suggesting a solution for the same problem occurring in different contexts. Similarly, an IoT pattern provides a guide to design an IoT solution with the difference that the software is not the only element involved. Starting from this idea, we propose the novel concept of the IoRT pattern. To the authors' knowledge, this is the first attempt at pattern authoring in the Internet of Robotic Things context. We focus on pattern identification by abstracting examples also in the Ambient Assisted Living (AAL) scenario. A case study providing an implementation of the proposed patterns in the AAL context is also presented and discussed. [ABSTRACT FROM AUTHOR]

This paper, for the first time, investigates the possibility of exploiting a nonlinear bistable snap-through buckling structure employing piezoelectric transducers, to implement an autonomous sensor of mechanical vibrations, with an embedded energy harvesting functionality. The device is operated in the presence of noisy vibrations superimposed on a subthreshold deterministic (sinusoidal) input signal. While the capability of the device to harvest a significant amount of energy has been demonstrated in previous works, here, we focus on the signal processing methodology aimed to extract from the sensor output the information about the noise level (in terms of the standard deviation) and the root mean square amplitude of the deterministic component. The developed methodology, supported by experimental evidence, removes the contribution to the overall piezoelectric output voltage ascribable to the deterministic component using a thresholding and windowing algorithm. The contribution to the output voltage due to the noise can be used to unambiguously estimate the noise level. Moreover, an analytical model to estimate, from the measurement of the output voltage, the RMS amplitude of the deterministic input and the noise-related component is proposed. [ABSTRACT FROM AUTHOR]

Magnetic field sensors are successfully used in numerous application contexts such as position sensing, speed detection, current detection, contactless switches, vehicle detection, and electronic compasses. In this paper, an inkjet printed magnetic sensor, based on the magneto-mechanical sensing principle, is presented together with a physical model describing its physical behavior and experimental results. The main novelties of the proposed solution consist of its low cost, rapid prototyping (printing and drying time), disposability, and in the use of a commercial low-cost printer. A measurement survey has been carried out by investigating magnetic fields belonging to the range 0–27 mT and for different values of the excitation current forced in the actuation coil. Experimental results demonstrate the suitability of both the proposed sensing strategy and model developed. In particular, in the case of an excitation current of 100 mA, the device responsivity and resolution are 3700 µε/T and 0.458 mT, respectively. [ABSTRACT FROM AUTHOR]

Ageing is a global phenomenon which is pushing the scientific community forward the development of innovative solutions in the context of Active and Assisted Living (AAL). Among functionality to be implemented, a major role is covered by falls and human activities monitoring. In this paper, main technological solutions to cope with the aforementioned needs are briefly introduced. A specific focus is given on solutions for Falls recognition and classification. A case of study is presented, where a classification methodology based on an event-driven correlation paradigm and an advanced threshold-based classifier is addressed. The receiver operating characteristic (ROC) theory is used to properly define thresholds' values while, in order to properly assess performances of the classification methodology proposed, dedicated metrics are suggested, such as sensitivity and specificity. The solution proposed shows an average Sensitivity of 0.97 and an average Specificity of 0.99. [ABSTRACT FROM AUTHOR]

The use of inexpensive gas sensors is a real need for many applications requiring the use of disposable sensors. This work deals with the realization and characterization of a low cost CO2 sensor realized by rapid prototyping techniques. In particular, the sensor consists of a set of InterDigiTed electrodes, over which a double sensing layer made of PEDOT/PSS (CLEVIOS™ PHCV4, by H.C.Starck) and a solution of pristine graphene powder has been deposited. A silver nano-particle solution is used for inkjet printing the electrodes onto the PET (PolyEthylene Terephthalate) substrate, through a commercial inkjet printer. The sensing strategy is based on the variation of the electrical conductance of graphene due to gas molecules adsorption. The device responsivity observed in two different operating conditions (50 °C and 60 °C), is 4.0 µΩ/Ω/ppm and 4.7 µΩ/Ω/ppm. The corresponding values of the resolution are 400 ppm and 420 ppm. Main advantages of the developed sensor consist in the cost-effective fabrication techniques and the device flexibility, which are strategic for applications requiring disposable and shapeable devices to be installed into irregular surfaces. [ABSTRACT FROM AUTHOR]

The development and realization of micropipettes and micropumps has captured the interest of people working in both biomedical and chemical areas for the capability of managing very low quantity of liquid (drug, biological liquid or expensive reagent) as well as everyone interested in controlling small flows for dedicated applications. In this paper a novel ferrofluidic pump adopting an electromagnetic actuation is proposed. The pump is realized by injecting three drops of ferrofluids into the pipe (two valves and a plunger are required) in the position where the pump must operate and by exploiting the forces produced onto each ferrofluid drop by some coils externally placed with respect to the pipe. The absence of any mechanical moving parts, the possibility to realize a volumetric pump in a section of an existing pipe without interruptions and deformation are the main advantages of the architecture proposed as compared to existing prototypes. A detailed description of the strategy proposed is presented along with a preliminary characterization of the prototype developed.