Sensors and Microsystems

The Seebeck effect in ZnO (

n

-type) and CuO (

p

-type) nanowire bundles grown on alumina substrates has been investigated. By combining

n

- and

p

-type nanostructured elements, a planar thermoelectric device has been proposed and characterized, confirming the feasibility of fabricating planar thermoelectric generators based on metal oxide nanowires with the future aim of powering autonomous sensors and microsystems.

During the last 10 years, the structural health monitoring (SHM) technique based on Lamb waves, involving intelligent sensors spread on the structure like biological receptors on the human body, achieved good and promising results showing broad-based economic benefits. There are a few who demonstrated SHM systems based on the use of a network of piezoceramic sensors applied directly to the structure for monitoring and surveying, controlled by a dedicated control unit, the health of the structure itself (detection of cracks, delaminations, disbonds, and corrosion to monitoring the mechanical impacts on metal and composite structures, etc.). The work describes a new approach for the development of this SHM system based on flexible piezopolymer transducers (PPTs) which have some advantages over the piezoceramic thin disk transducers in space applications.

We will report results about the noise and performance of magnetic nanosensors based on niobium nano superconducting quantum interference device (nanoSQUID) having a flux capture area of 0.5 μm

2

. A proper device design based on a loop inductance asymmetry has been developed in order to achieve a better magnetic flux resolution. The device fabrication procedure is based on the electron-beam lithography, thin film deposition, and the lift-off technique. The characterization of the nanodevice at

T

=4.2 K includes measurements of current–voltage, critical current vs. magnetic flux characteristic (

I

−Φ), and flux noise. The nanosensors have shown a hysteretic

I

–

V

characteristic and a triangular-shaped

I

−Φ pattern. Due to the hysteretic behavior, the devices have been employed as a magnetic flux to current transducer. In such a configuration, an overall magnetic flux resolution of about 0.1 mΦ

0

has been estimated. A proper feedback circuit has been employed to increase the dynamic range of the nanosensor. Magnetization measurements at

T

=4.2 K on Fe

3

O

4

nanoparticles having a size of 8 nm have been reported, proving that nanoSQUIDs reported here can be successfully employed to investigate the magnetism at a sub-micrometric scale.

The chapter describes an innovative IR sensor properly conceived for real-time measurements of the gas turbine inlet temperature. The sensor is based on the measurements of the radiation emitted in a given wavelength band by the CO

2

molecules present in the combustion gas. Experimental results relevant to laboratory tests aimed at characterizing the techniques will be presented.

In this chapter, an optoelectronic Lab-on-Chip system for DNA amplification integrating a polydimethylsiloxane microfluidic structure with indium tin oxide heaters on a 5 × 5 cm

2

microscope glass slide is presented. The microfluidic structure comprises a channel for the fluid handling and a reaction chamber for the polymerase chain reaction (PCR). Two lateral heaters, located at the inlet and outlet positions of the chamber, actuate the valves and allow the chamber isolation, while the last one, positioned below the chamber, is dedicated to the PCR thermal cycle. In order to optimize heaters and valves geometry, the temperature distribution over the heaters and the membrane valve deformation have been studied using the commercial software COMSOL Multiphysics. The microfluidic structure has been fabricated by using soft lithography techniques on one side of the glass substrate, while the thin film heaters were deposited and patterned on the opposite glass side. Experiments show that valve activation begins around 60 °C, and complete closure is observed around to 100 °C, without any loss of liquid from the chamber.

A microfluidic sensor for detection of cells flowing in a microchannel is presented. The sensor consists of a PolyDiMethylSiloxane layer with two planar microreservoirs connected by a microchannel. The bottom sides of the microreservoirs are faced to two sensing electrodes formed on a printed circuit board. A noncontact measurement is ensured by an insulator layer between the electrodes and the fluid. Particles flowing in the microchannel cause changes in the conductivity of the narrow path formed by the fluid, producing variations in the impedance between the electrodes. A tailored electronic interface based on a direct digital synthesis device is proposed to measure the impedance variations. In the experimental tests, the cell flow is detected by changes in the effective capacitance and conductance between the electrodes. These preliminary results are promising for biological measurements such as counting and sizing of cells in different matrices.

The present work deals with the influence of high pressure, pressing time and thermal ageing of powdered samples of polyaniline (PANI) on the conductivity. We compared the results obtained for PANI prepared following two different methods: a classical and a “green” approach.

Fire prevention is one of the main topics regarding home safety of old-renovated and newly built buildings. While it is possible to install modern fire extinguisher system in new houses, during house building, to prevent and stop fires in the old ones, it is easier and less expensive to place some portable automated system to perform this task. To create an automated system, a sensor to localize a fire in a closed environment such as a room is necessary. The sensor has to provide the coordinates of the fire onset to an automated arm with a fire extinguisher. The sensor is based upon a couple of matrix of thermopiles; as a result, their images are opportunely elaborated and they give the dimensional position of the fire onset where the fire extinguisher will direct its beam. This system is a very promising system in closed environment, due to its cost and relative simplicity of installation in order to better prevent fire propagation.

In this work, a method for localization, recognition, and classification of a superficial seismic source in a real geological medium is presented. Localization is based on the DOA (Direction of Arrival) and on RSSR (Received Signal Strength Ratio) algorithms applied after Love and Rayleigh superficial wave separation. Recognition and classification methods make use of PCA (Principal Component Analysis) and K-means algorithm. The efficiency of this method is illustrated with experimental results.

A novel

p

–

v

probe for the measurement of the acoustic impedance is proposed. The device is fabricated assembling a micromachined acoustic particle velocity sensor, a commercial microphone, and an electronic read-out interface. The velocity sensor consists of two integrated polysilicon heaters placed over suspended dielectric membranes. The sensor has been designed with a commercial CMOS process and fabricated using a simple post-processing technique. The electronic interface is based on a Wheatstone bridge and a low noise instrumentation amplifier. Preliminary tests confirm the functionality of the proposed probe.

Recent developments in MEMS technology made available a new class of thermo-resistive sensors to be used as functional devices for acoustic particle velocity,

v

, measurements (Bruschi and Piotto, IEEE Sensors Proceedings 1405–1408, 2011). A very interesting feature of this new generation of

v

-sensors—distinguishing them from the Microflown

®

ones (de Bree et al., Sens Actuators A Phys 54:552–557, 1996)—is their compatibility with standard CMOS industrial processes, so allowing to integrate in the same chip both the sensors and read-out electronic circuits. This added flexibility of

v

-sensors, combined with miniature or MEMS microphones, allows of setting up pressure–velocity (

p–v

) microprobes for specific applications, in particular when the reduction of production costs is decisive for marketing strategies. In many applications, in fact, carefully designed functional devices can be safely used, without prejudice to the reliability and the robustness of the required measurement process. In other words, the required measurement precision can be achieved despite the low signal-to-noise ratio or limited band frequency response of the used

p–v

microprobes. This article shows a first comparison between the two kinds of sensors.

Fiber optic-based mechanical sensors, thanks to their reduced sensitivity to external electromagnetic fields, are promising in the development of biomechatronic systems able to work in demanding environments, such as MRI chambers. In this chapter we report on the working principle, design, and experimental characterization of a micro-opto-mechanical displacement sensor, which exploits the light modulation induced by the relative displacement of two overlapped micro-fabricated gratings. The gratings are obtained by photo patterning a Pt layer (45 nm thick), sputtered on a Pyrex substrate, into an array of stripes, 150 μm wide and with a 525 μm period. The calibration was carried out up to 525 μm displacement. The sensor showed high and constant sensitivity in the ranges from 30 to 140 μm and from 360 to 490 μm. The experimental data, together with the known advantages of fiber optic-based sensors, encourage further studies for the development of sensors exploiting the proposed measurement principle.

Nowadays, acoustic antennas are used in different application fields with the primary aim of detecting the presence and the position of acoustic sources. The uncertainty in the evaluation of the acoustic source position is related to the knowledge of right acoustic locations of the microphones in the array, which is different from the geometric ones and needs a suitable calibration procedure to be evaluated. This paper, after an analysis of the problems related to the calibration of acoustic antennas, proposes a dedicated strategy with the aim of assessing an optimized experimental setup guaranteeing the best uncertainty in the acoustic source location.

The aim of this project is to develop an automated system in order to measure electrical impedance of ultrasonic piezoelectric actuators that work at frequencies close to 55 kHz. The main application of this system is related to the control of the operation and the quality of commercial actuators employed in ultrasonic scalpels. The study of the frequency behavior of the actuator through the automatic measurement of the impedance is used to determine failures and aging phenomena. The project refers to a particular type of ultrasonic scalpel made with a “stack” of ring piezoelectric actuators but in general includes also the characterization of piezoelectric actuators with an operating frequency of lower than 500 kHz.

The amperometric determination of strong oxidising species has been carried out through an unusual electrode material, namely, Ti. In particular the study involves H

2

O

2

and HClO, even at high concentration levels. A complex real matrix, such as an industrial detergent, containing high H

2

O

2

concentrations, has been taken as a meaningful study case to check the effectiveness of the electrode system and procedure proposed.

In this work a new kind of electronic nose, based on modified quartz crystal microbalance (QCM) array of gas sensors, is presented. The QCM surfaces have been covered with gold nanoparticles (GNPs) bearing short peptide moieties. The array was composed of eight modified QCM, one carrying only GNPs without the peptide moiety and seven modified with peptides. Three peptides were synthesized in order to test the response variability to different amino acid sequences of the same length. Electronic nose has been challenged with pure compounds and real food sample analysis demonstrating its ability to discriminate between different aroma patterns after simple statistical analysis such as PCA.

The monitoring of dissolved oxygen (DO) in water is of great interest in order to provide information concerning the presence of pollutants or more generally about the health state of aquatic ecosystems. The majority of existing dissolved oxygen analyzers use electrochemical sensors which are accurate, reliable, stable, and require low or zero maintenance. However, these commercial sensors are not very compact and relatively expensive, since the fabrication process is complicated and noble metals are normally used as electrode materials. Herein, we present an electrochemical sensor for the determination of dissolved oxygen, by using reduced graphene oxide (RGO) as the oxygen sensitive probe. We prepared RGO by a chemical reduction method from graphene oxide (GO). A simple sensor was fabricated by printing RGO dispersed in Nafion, on the working electrode surface of a flexible commercial device. The surface and morphological properties of the sensing layer were investigated by XPS and TEM analysis. The electrochemical characteristics of the RGO-modified electrode were investigated by cyclic voltammetry (CV). Amperometric measurements were also performed in order to evaluate the sensor performance. Preliminary tests show good sensitivity and reproducibility. Tests of dissolved oxygen monitoring on environmental samples show the possibility of use in real applications.

This is a short overview of the COST Action TD1105 EuNetAir—

European Network on New Sensing Technologies for Air-Pollution Control and Environmental Sustainability

—funded in the framework European Cooperation in the Field of Scientific and Technical Research (COST) during the period 2012–2016. The main objective of the concerted action is to develop new sensing technologies for air-quality control at integrated and multidisciplinary scale by coordinated research on nanomaterials, sensor systems, air-quality modeling, and standardized methods for supporting environmental sustainability with a special focus on small and medium enterprises.

Hydrocarbons are considered one of the most important and dangerous pollutants for environment, in general, and for marine environment in particular. Their detection can be performed in several ways, employing different kinds of systems, such as fixed gas analyzers or gas chromatographs, to be mainly used in laboratory, or portable analyzers, having good performances but a considerably high cost.

In this paper, an innovative approach to overtake this problem is proposed by using an array of commercial sensors properly placed into a flow chamber and managed via a control electronics.

An artificial neural network was designed, realized, and properly trained in order to detect the concentration of the hydrocarbons detected and to discriminate the detected hydrocarbon from a given dataset. Results obtained were satisfying, with good performances of the neural network proposed, probably representing a good basis for future systems based on electronic nose technology.

Titanium oxide nanofibers were successfully prepared via thermal treatment of electrospun composite polymer (PVP)/TiO

2

nanofibers. The morphology and crystal structure were characterized by SEM and TEM. It was confirmed that the calcination process was responsible for the removal of PVP component and the growth of crystalline TiO

2

. The resulting nanofibers, which have a quite rough surface, an average diameter of 60 nm and a length reaching hundreds of μm, were found to be formed by the agglomeration of TiO

2

nanoparticles with brookite phase. Gas-sensing tests towards ethanol demonstrated n-type sensing response and good reversibility at an operating temperature of 450 °C. A first tentative to model electrical impedance spectra was made in order to understand charge transport in relationship with morphological and structural aspects.

Accurate and stable measurements of volatile organic compound (VOC) at trace level in air are required for global climate change models, air quality studies, and real-time industrial monitoring. A repeatable and stable gas measurement system calibrated against accurate gas standards is then required, preferably not cumbersome or expensive as the state-of-the-art gas chromatographs. In this work a compact and cheap measuring system based on a commercial photoionization detector is projected. A metrological characterization of the detector defines the conditions for the realization of a 3 % reproducible and 0.1 %/h stable VOC concentration measurement.

In this paper, electrospinning technique has been employed to synthesize In

2

O

3

/PVP (indium oxide/polyvinylpyrrolidone) composite fibers. The produced In

2

O

3

fibers after annealing at 600 °C were investigated as sensitive layer in resistive sensors for monitoring NO

2

at low concentrations in air. By optimizing the spinning conditions and the subsequent annealing treatment, In

2

O

3

fibers have been successfully obtained. The annealed samples have a high crystallization degree. Their sensing behavior towards nitrogen dioxide has been then tested both in the dark and under UV light. To analyze in detail the effect of UV radiation, sensing tests have been performed by using three different procedures: without UV illumination, under continuous UV illumination, and under pulsed UV illumination (provided only during the recovery time). It has been proved that the optimal sensing characteristics (higher sensibility and very shorter recovery time) of the sensor occur when the sample is irradiated with pulsed UV light.

NiO thin films were deposited by RF reactive magnetron sputtering and investigated in view of application as p-type material for sensing of pollutants. The thin films were deposited on Si-wafer, glass and alumina substrate using a nickel oxide target at variable gas mixture of O

2

/Ar. Ratio of O

2

/Ar was varied from 0, 10, 25 to 50 %, and the deposition temperatures were varied from RT to 400 °C. The phase formation and structural analysis of the samples were analysed by GIXRD (glancing incidence X-ray diffraction). GIXRD confirmed the NiO phase formation in thin film deposited at 50 % O

2

content. Surface morphology was analysed by scanning electron microscope (SEM). The thin films deposited are flat and uniform: in some cases, we found tetrahedral-shaped particles with dimension ~30 nm. We observed that the oxygen content in the gas mixture of O

2

/Ar and post-deposition annealing temperature were the crucial factors which have deep impact to tailor the structural properties and the surface morphology of thin NiO films. The gas sensing properties of the designed systems were investigated in the presence of ethanol, NO

2

and CO, respectively, with variable temperature from 200 to 400 °C. A good response was obtained towards NO

2

at 300 °C operating temperature and to ethanol with optimum working temperature at 400 °C. A low response was observed towards CO.

Fabrication of TiO

2

and Nb-containing TiO

2

nanotubes on alumina and flexible polymeric substrates Kapton HN has been performed by means of electrochemical anodization method. To investigate the morphology of the structures and the roughness of the substrates, scanning electron microscopy and atomic force microscopy have been utilized. The preparation of well-ordered titania structures with the higher concentration of Nb was possible when in the electrolyte the ethylene glycol has been substituted by more viscous glycerol. Sensing properties of obtained tubular arrays have been tested towards nitrogen dioxide.

In this paper a gas sensor for low concentration of ammonia detection realized by a low-cost printed technology is presented. The proposed sensor behaves in an integral mode up to 100 ppm of ammonia, and it is particularly suitable for applications where fast response, low cost, and the availability of disposable devices are mandatory.

The potential of graphene as sensing layer relies on its two-dimensional nature that provides the greatest sensor area per unit volume. Thanks to this property, besides the highest mobility and the lowest resistivity values, graphene has put itself as the leader of the new discovered materials in every research field. Graphene can be produced by various approaches including micromechanical exfoliation of graphite, thermal dissociation of SiC, chemical vapor deposition, or by low-cost approaches such as chemical exfoliation methods. However, the sensor device development is still affected by several technological limitations mainly related to graphene preparation, introduction into device architectures, and reproducibility of the sensor performances. Regarding the last item, sensing performance may differ from device to device even though graphene materials come from the same batch and the same fabrication protocol. In this work, chemiresistive devices based on chemically exfoliated natural graphite are presented. Several parameters were taken into account: graphene preparation (including solvents, centrifugation speed, and batch), deposition, and conductance. Finally the device-to-device variation is addressed.

In this work we report on the development of an eco-friendly method for the chemical exfoliation of graphite in order to produce high-quality graphene for sensing applications. A mixture of low-boiling-point solvents, such as 1-butanol and 2-propanol, was employed for this purpose. The resulting colloidal suspension was a stable dispersion of few-layer flakes. This material was employed to fabricate chemiresistor devices that showed a remarkable variation of conductance when exposed to 350 ppb of NO

2

.

In this paper the development of a measurement setup for resistive films able to perform sensing tests within a wide resistance range is reported. The system is fully automated, allowing to perform time-consuming sensing tests without operator supervision. Here, a thick film planar-type sensor was investigated. Cu-doped SnO

2

was used as sensing element deposited by screen printing on the planar ceramic substrate provided with Pt interdigited contacts. First results showed a predictable behavior vs. low values of humidity and a satisfactory attitude to thermal stress. The system is a promising tool both in sensing performance film evaluation and in device prototype characterization.

In ENEA, at Brindisi Research Center, a portable gas sensor system called NASUS IV based on solid-state gas sensors was built. This system is the last result of our technology researches in the area of tiny and portable sensor systems for air quality control. The main goal of the system designed and built in our laboratory is the development of a handheld device for detecting some pollutant gases such as CO, SO

2

, NO

2

, and H

2

S. In order to test this machine in our laboratory under conditions similar to real situations, we employed a wide-volume gas chamber provided by an input and an output pipe. We put NASUS IV in the previously mentioned chamber, and we performed several tests with different kind of targeted gases. Future works concern about the employment of the NASUS IV in real environment by performing an experimental campaign in collaboration with the public regional environmental protection agency (ARPA-Puglia), which will provide in-field fixed stations in order to compare the performance of our machine with the conventional gas analyzers.

Traces of several herbicides belonging to different classes of pesticide were tested in sunflower oil, and good results were obtained using a new organic phase immuno-electrode (OPIE). Both the competition step and the final enzymatic measure were carried out in optimised organic solvents. Using the new OPIE the pesticides 2,4-D and 2,4,5-T (i.e. agent orange herbicides), atrazine and simazine (triazinic pesticides) and parathion (organophosphate pesticide) were tested without problems in sunflower oil.

The immunoassay developed for Mucin 1 (MUC1) detection is based on a sandwich format in which a primary antibody immobilized on the surface of magnetic beads specifically binds the MUC1 protein. The sandwich immunoassay is performed by adding secondary anti-MUC1 and an alkaline-phosphatase-labeled third antibody. After, the modified magnetic beads are captured by a magnet on the surface of a graphite working electrode, and the electrochemical detection is thus achieved through the addition of 1-naphthyl phosphate. 1-naphthol, produced during the enzymatic reaction, is detected using differential pulse voltammetry (DPV). The performance of the assay in terms of sensitivity, reproducibility, and selectivity has been studied. MUC1 detection is performed in buffered solutions and serum sample.

The present paper describes a study to assess the catalytic efficacy of a new ceramic membrane containing titanium dioxide and irradiated by UV light used to abate the pollutant load of olive oil wastewater. Good results were obtained, particularly in comparison with those offered by catalytic membranes constructed using other materials.

In this work, a simple and sensitive approach for VEGF detection using antibody-aptamer assay and gold screen-printed electrodes as transducers is presented. The assay was performed in a sandwich format. Anti-VEGF antibody was first chemically immobilized on the gold working electrode surface of screen-printed cell. After the incubation with the antigen, the sandwich assay was realized by incubation step with biotinylated anti-VEGF aptamer. The sensor was then incubated with streptavidin-alkaline phosphatase and with 1-naphthyl phosphate. Differential pulse voltammetry (DPV) measurements were performed to detect VEGF biomarker.

MicroRNAs (miRNAs) are intensely studied as candidates for diagnostic and prognostic clinical biomarkers. Faradic impedance spectroscopy (EIS) and differential pulse voltammetry (DPV), coupled to disposable gold electrodes and enzyme amplification of the hybridization event, were used for the development of biosensors for the detection of miRNAs. Biotin-labeled liposomes were employed as nanointerfaces that amplify the primary miRNA-sensing events by their association to the probe–/DNA–miRNA–analyte complex generated onto the transducer.

A lab-on-chip for the diagnosis of celiac disease relying on the monitoring of patient-specific immune response to gliadin fractions has been developed. The detection is based on a chemiluminescent immunoenzymatic reaction that ensures high specificity and sensitivity. The chemiluminescent signal is monitored by hydrogenated amorphous silicon photosensors, fabricated on the same glass substrate hosting the biochemical recognition. The main challenge of the work has been the identification of the materials and the setup of the entire process that permitted the reliable fabrication of the device. Experiments performed with serum samples of rabbit immunized towards an epitope show a good specificity of the proposed technique, proving the feasibility of an integrated device for the patient-specific profiling.

The development and characterization of a novel antibacterial material based on glucose oxidase (GOx) immobilized in a polyvinyl alcohol (PVA) film was proposed. This system acts in the presence of glucose to generate by-products as oxygen species (H

2

O

2

, ·O

2

−

, OH) that are well-known endogenous and exogenous toxic products for microbes in vivo (Miller and Britigan, Clin Microb R10: 1–18, 1997). The PVA/GOx composite material has been extensively characterized by X-ray photoelectron (XPS) spectroscopy, Fourier transform infrared (FTIR), and UV-visible spectroscopy (UV–vis) to verify the preservation of the enzyme structural integrity and of the enzymatic activity in PVA membrane. The antibacterial lysozyme-like activity of PVA/GOx was evaluated by a standard assay on Petri dishes employing

Micrococcus lysodeikticus

dried cell walls.

In this study, we have used a direct immunoassay where the simple binding between antigen and an antibody is detected. Immunoassays were performed in a drop system, monitoring the decrease in the frequency of the quartz crystal microbalance device as the mass increases during immunoreaction. The QCM sensor was coated on both sides by gold electrodes; only one side of the crystal (liquid side) was in contact with the solution, the other side (contact side) was always dry. We tested a piezoelectric immunosensor for aflatoxin B1 (AFLA-B1), ochratoxin A (OTA), and fumonisin B1 (FB1) mycotoxin detection through the immobilization of DSP–anti-mycotoxin antibody (AFLA-B1–Ab anti-AFLAB1, OTA-Ab anti-OTA, FB1-Ab anti-FB1) on gold-coated quartz crystals (AT-cut/5 MHz). The DSP (3,3′-dithiodipropionic-acid-di-

N

-hydroxysuccinimide ester) was used for the covalent attachment of the proteins. The piezoelectric crystal electrodes were pretreated by DSP for 15 min, rinsed with water, and dried in a gentle flow of nitrogen gas. Then the DSP-coated crystals were installed in a sample holder and exposed to the antibody and to the analyte. Frequency and resistance shifts (Δf and ΔR) were measured simultaneously.

Long-period gratings have been recently proposed as label-free optical devices for biochemical sensing. Fiber bio-functionalization was performed using Eudragit L100 copolymer as opposed to the commonly used silanization procedure. An IgG/anti-IgG bioassay was carried out for studying antigen/antibody interaction. The biosensor was characterized, monitoring in real time all the bioassay steps and achieving the calibration curve of the assay. By comparison, two LPG-based biosensors with distinct grating periods were characterized following the same bioassay protocol. Experimental results demonstrated an enhancement of the biosensor performance when the coupling occurs with a higher-order cladding mode. Considering an LPG manufactured on a bare optical fiber, in which the coupling occurs with the seventh cladding mode, a limit of detection of 500 ng mL

−1

was achieved.

In this paper we present a chemiluminescence-based micro-total-analysis system integrating amorphous silicon for on-chip detection as a technically feasible solution to develop “true” lab-on-chip systems, intended as stand-alone devices implementing all the analytical steps from sample preparation to on-chip detection. The achieved performances are comparable to that of the state-of-the-art lab equipment demonstrating that such systems would enable the development of a variety of point-of-care testing systems, opening new analytical application scenarios.

Two different kinds of soybean oil were adulterated with a low-quality “hogwash” oil, extracted from oxidized oils and other leftovers. Adulterated mixtures with hogwash concentrations ranging from 5 to 75 % were prepared and analyzed by means of absorption spectroscopy in the visible range. Another mixture set was prepared for validation purposes. All spectra were first analyzed by means of Principal Component Analysis (PCA) for explorative purposes. Then, for each soybean oil, a dedicated Partial Least Square (PLS) model was created for quantitative determination of adulterant concentration. Very good results were obtained with one-factor PLS models, giving determination coefficients higher than 0.99 and Root Mean Square Errors ranging between 1 and 2.5 % in both calibration and validation.

In this work, an ultra-compact in-line fiber-optic Fabry-Perot interferometer is presented. The interferometric structure consists of a thin (<1 μm) amorphous silicon layer in line integrated into a standard single-mode optical fiber by means of an electric arc discharge technique. The device exhibits low loss (1.46 dB) and high interference fringe visibility (~30 % in linear scale) both in reflection and transmission due to the high refractive index contrast between silica and α-Si. A high linear temperature sensitivity up to 75 pm/°C is demonstrated in the range 15–52 °C. The proposed device is simple, compact, cost-effective, and attractive for point monitoring sensing application in ultra-high-temperature sensing in harsh environments.

This paper reports a microflow cytometer fabricated in polymethylmethacrylate (PMMA) in which a 3D hydrodynamic flow focusing is employed in order to align the particles in a single line along the focused stream. By exploiting an innovative and simple technique to realize a 3D hydrodynamic focusing effect, a tunable and circular-shaped focused stream has been obtained. The device has been fabricated by direct micromilling of two parts of PMMA that were finally bonded together. Flow cytometry measurements have been performed by using 10 μm-sized fluorescent particles. From the analysis of the fluorescence signals collected at each transit event, we can confirm that the device is capable of creating a single-file particle stream.

The design of a magnetic field sensor system based on clad-etched fiber Bragg grating (FBG) sensors is presented in this chapter. When magnetic field monitoring is performed in electronically harsh environments, conventional measurement systems may not be reliable due, for example, to the effects of high levels of ionizing radiation or electromagnetic fields. Fiber Bragg gratings (FBGs) have features that lend these devices suitable to operate in harsh environments, but an appropriate design of the optoelectronic device is needed in order to work as a magnetic field sensor, since FBGs are natively insensitive to magnetic fields. Using magnetic fluids as sensing materials, FBGs can be used to detect magnetic field.

The purpose of this work is to realize a low-cost sensor for measuring the clay moisture, by metering the reflection at two different laser wavelengths, 1,300 and 1,500 nm. This kind of reflection measurement is well known: the standard implementation employs a lamp and a series of optical filters, selected sequentially by a mechanical handling system. In order to simplify the system, the proposed sensors employ two laser-diode sources and a single photodetector, without moving parts or optical filter. The measurement of different reflections is made working in time division multiplexing. Custom low-noise electronics allows rejecting ambient light disturbances and digital processing makes the system independent of the clay distance.

The “lab-on-fiber” technology has been recently proposed as a valuable route for the realization of novel and highly functionalized technological platforms completely integrated in a single optical fiber in communication and sensing applications. As a follow-up of the proposed technological approach, here, we present recent results on the fabrication of metallo-dielectric structures on the optical fiber tip by using a self-assembly technique. Our studies aim to attain advanced nanostructured sensors by exploiting easy and low-cost fabrication processes suitable to be employed in massive production of technologically advanced devices. The pursued approach basically consists in the preliminary preparation of a patterned polymeric film by the breath figure technique, directly on the optical fiber tip, and in the successive metal deposition by evaporation. The experimental results demonstrate the successful creation of a metallo-dielectric honeycomb pattern on the optical fiber tip. The sensing properties of the optical fiber probes have been successfully explored in terms of sensitivity to the surrounding refractive index changes demonstrating their potentialities for chemical and biological sensing applications.

Sensing schemes based on Rayleigh anomalies (RAs) in metal nanogratings exhibit an impressive bulk refractive-index sensitivity determined solely by the grating period. However, in this work, we demonstrate that the surface sensitivity (which is a key figure of merit for label-free chemical and biological sensing scenarios) cannot be attributable to the wavelength shift of the RAs, which are completely insensitive to local refractive-index changes but rather to a strictly connected plasmonic effect. Our analysis for increasing (up to wavelength-sized) overlay thickness reveals an ultimate surface sensitivity that approaches the RA bulk value (depending solely on the grating period), which turns out to be the upper limit of grating-assisted surface plasmon polariton sensitivities.

Fluence (J/cm

2

) and reflectance are key parameters in pulsed laser ablation processes. The dynamics and rate of the material removal are strictly dependent on the energy dissipated into the material under irradiation, which is complementary to the reflected energy. Laser cleaning of artifacts of cultural interest is a well-known application of laser ablation, which significantly grew along the last decade. The Long Q-Switch Nd:YAG laser (1,064 nm, τ=120 ns) is one of the most used laser systems (Salimbeni et al., J Cult Herit 4(1):72–76, 2003; Cacciari et al. Chem 402(4):1585–1591, 2012; Siano et al.,

Appl Phys A

106(2):419–446, 2012). This is usually equipped with optical fiber beam delivery terminated with a handpiece including an imaging lens and a mechanical arrangement to vary the fiber-to-lens distance in order to suitably set the laser spot diameter at the target. In this way, skilled restorers can set the operating fluence according to the interaction phenomenology observed. Here, a novel laser handpiece equipped with optical sensors in order to monitor fluence at the target and its reflectance, as well as the optimum working distance, is presented.

We report on an advanced optical fiber sensing implementation enabling submeter resolution over long distance exploiting Brillouin optical time-domain analysis with differential pulse-width pair. Long sensing distances have been attained thanks to the combined use of distributed Raman amplification of optical signals together with optical pulse coding. We experimentally demonstrate strain–temperature sensing capabilities with a spatial resolution better than 50 cm throughout 93 km standard single-mode fiber, attaining accuracy in terms of measured strain and temperature smaller than 1.7 °C and 34 με, respectively.

An optofluidic sensor based on a liquid-jet waveguide is presented. The waveguide consists of a high-speed water jet produced by means of a microchannel coupled with a multimode optical fibre collecting the fluorescence opportunely excited. The liquid jet acts, at the same time, as the solution to analyse and as an optical waveguide. This configuration allows a strong reduction of the scattering and fluorescence of non-analyte substances enabling a very low limit of detection (LOD). The integrated device is fabricated by PMMA micro-machining allowing a self-alignment between the liquid-jet waveguide and the optical fibre used to deliver the fluorescence to the detector. The performance of the system has been tested on Cy5 water solutions and LOD of 2.56 nM has been obtained. A proof-of-concept of filter-free measurements has been performed demonstrating that fluorescence measurements can be performed also by using a photodiode with an LOD of 6.11 nM.

Gordon Moore, a cofounder of the largest company in the manufacture of microchips in the world (INTEL), since the early development of microelectronics technology, formulated a predictive rule on the development of semiconductors, which became known as “Moore’s First Law” and, since its formulation, has virtually kept its validity up to now. It goes something like this: the density of integrated components on a chip will double every 2 years.

Subsequently, and to justify a remark done by a colleague (Rock) who was in charge of investments, Moore expressed a second consideration, related in some measure to the first law, about the nature and investment that would have required over time for the fabrication of complex structures built with microelectronics technology. It is this: “The investment to build a new microprocessor technology grows exponentially with time” [http://it.wikipedia.org/wiki/File:Seconda_legge_di_moore.jpg], an approach that reflects the comments of his colleague Rock who had just seen in his final balances that “The cost of the equipment to manufacture semiconductors doubles every 4 years”. There are other consequences related to the observations of Moore and Rock, although those already highlighted allow to understand that there is at least an indefinite economic limit to the increase of artificial complexity.

Apart from the above, going to the scientific reasons that are the basis of what was found by Moore, much more interesting and important consequences emerge from the comparison between the artificial complex systems such as those referred to by Moore and the natural living systems.

This work reports the development of a micro thermoelectric generator based on planar technology using electrochemical deposited process with constantan and copper thermocouples on a micromachined silicon substrate. This configuration was selected because it can be manufactured into large area, flexible substrates, and the selected materials can be deposited with low-cost process. Efficiency of the module was investigated in different working condition, showing a maximum generated potential of 118 V/cm2 and a power of 1.1 μW/cm2. Constantan alloy electrodeposited at different deposition potential was characterized by Energy Dispersive X-ray Spectroscopy (EDX) and Scattering Electronic Spectroscopy (SEM) to observe the morphology and composition of the films.

Several SiO

2

films were deposited on stainless steel substrate by means of a low-temperature HMDSO-PECVD process under different conditions. Adhesion to substrate was determined by scratch testing and the influence of metallic interlayers deposited by magnetron sputtering was investigated. Electrical properties of the films were assessed by DC and AC tests before and after thermal ageing and bending tests. None of the measured films resulted to be altered by thermal ageing, while in many case bending test caused a reduction of the adhesion and the formation of microscopic cracks which induce a loss in dielectric properties. Under certain particular conditions, however, the film is stable after both ageing and bending tests and the insulating properties of the films are comparable to the properties of silane-PECVD SiO

2

films.

In this work we propose a resonant mass sensor based on a CMOS-compatible MEMS bulk technology, targeted at the label-free, selective detection of biomolecules. Both the MEMS fabrication phase and the bioactivation protocol were designed to ensure functionality of on-chip test electronic circuitry. Specifically, the bioactivation steps were performed with single drops of the reagents on the active part of the chip to minimize impact on the electronics and package. The CMOS compatibility of the final device is demonstrated by simultaneous operation of the MEMS resonator and the test electronics. The resonator mass sensitivity, determined by resonator loading with gold nanoparticles, compares favorably with those of QCMs and other MEMS resonant mass sensors. To validate the device operation as a biosensor, synthetic oligonucleotide sequences designed to bind to a specific human mRNA (involved in the synthesis of human methylguanine-DNA methyltransferase, a DNA repair protein) were used as probes and covalently bound to the resonator surface. The resonance frequency shift of different sensors at the same concentration of the analyte confirms the inverse dependence of the sensitivity on the mass of the resonator.

In this paper we report on the integration, on a glass substrate, of a microfluidic network with a balanced photodiode constituted by two series-connected amorphous silicon/silicon carbide n-i-p stacked junctions. The photosensor is suitable for detection of small variations of photocurrent in biomedical application. The experiments have been carried out measuring the differential current under a large background light intensity to reproduce realistic operating conditions for a point-of-care analysis system. We have found that the proposed device is able to detect the presence or absence of water flow in the channel.

A theoretical comparison of the optical and electronic properties of metallic nanostructures characterized by complementary geometries is proposed in this work. Periodic array of nanoparticles on glass substrate and nano-holes on metal substrate have been analysed performing finite element analysis with the RF Module of COMSOL Multiphysics. Single and array of gold nanostructures have been studied, exploring several key parameters responsible for sensitivity enhancement of LSPR sensors. The analysed structures show a minimum in their spectral transmittance, confirming that regular arrays of nano-holes in thin metal films as well as nano-disk arrays may support localized surface plasmon resonance.

Falling down is one of the main causes of trauma, disability and death among older people. Inertial sensors and accelerometer-based devices are able to detect falls in controlled environments. The aim of this work is the development of a computationally low-cost algorithm for feature extraction and the implementation of a machine learning scheme for detection of fall events in the elderly, by using the 3-axial MEMS wearable wireless accelerometer. The proposed approach allows to generalize the detection of fall events in several practical conditions, after a short period of calibration. It appears invariant to age, weight, height of people and relative positioning area (even in the upper part of the waist), overcoming the drawbacks of well-known threshold-based approaches in which several parameters need to be manually estimated according to the specific features of the end user. The supervised clustering step is achieved by implementing a One Class Support Vector Machine (OC-SVM) classifier in a stand-alone PC. A polynomial kernel function is used in order to limit the computational workload while maintaining high performances in terms of reliability and efficiency.

A capacitive sensor for detecting the human heartbeat rate without direct contact with the skin is here described. The precordial movement changes the capacitance between the patch electrodes so modulating the frequency of an oscillator where the capacitance is inserted; as a consequence, the heartbeat signal can be obtained by demodulating the oscillating signal.

A system for gas flow measurement, based on MEMS flow sensing microstructures and a sigma–delta interface, is described. The sensing structures consist of double-heater differential microcalorimeters, obtained by means of a post-processing procedure applied to chips fabricated using the Bipolar-CMOS-DMOS process BCD6s of STMicroelectronics. Part of the sigma–delta modulator is implemented in the thermal domain by exploiting the versatility of the double-heater sensing structures. The measurements performed in nitrogen flow prove the effectiveness of the proposed approach.

Energy harvesting from vibration sources is emerging as interesting alternative power source for micro and nano devices. Therefore, reducing the device’s size implies also a reduction of the harvester. As consequence, a lower output voltage/power will be obtained. Obviously in order to store the energy provided by the transducer (e.g. piezoelectric), a particular electrical interface is required in order to rectify the alternate piezoelectric voltage. Unfortunately often its amplitude is under diode threshold; for this reason, standard solutions, based on classical diode-bridge rectifiers, cannot be used. Several approaches have been proposed in literature focusing the attention on innovative interface and novel conversion principles. Moreover these existing solutions (synchronized approach) present several limitations such as they work efficiently only under the hypothesis of a sinusoidal input and an accurate driving of electrical switches. It is worth noting that in many real situations, the input is random, low amplitude and broadband. In this paper, authors discuss about an innovative solution to overcome the previously highlighted problems. A new system is presented and here, in particular, the characterization of the system performance with respect to two crucial construction parameters has been highlighted. The system is composed of a piezoelectric transducer, a storage circuit and a mechanical switch driven by the same input vibrations, in which the mutual position of the electrical terminals is tunable (to evaluate the best performance). An analytical model, a simulation software and an experimental prototype have been implemented in order to verify the working principle and test the validity of the proposed approach.

Wireless sensor networks is a research field across multiple application areas: energy, environment, industry and health. Miniaturized, zero-power, real-time, self-organized, self-localized distributed measurements is the idea introduced by the well-known concept of Smart Dust (

http://robotics.eecs.berkeley.edu/~pister/SmartDust/SmartDustBAA97-43-Abstract.pdf

) more than 10 years ago. Low-power wireless communications [e.g. IEEE802.15.4 (IEEE802.15.4-2006 Spec.)] make possible a lot of applications; some solutions are on the market, not always miniaturized, zero-power, real-time and self-localized, but affected by some limitations. Industrial applications, especially for process control, are moving towards some standard solutions, as WirelessHART or ISA100. This presentation will analyse real implementations, in terms of pros and cons.

The paper describes the design, the technology, and the characterization of an array of 16 elements of airborne ultrasonic transducers. The array is connected to a dedicated electronic platform that provides the 16 channels programmable analog front-end electronics and the synchronization and data acquisition and transmission for real-time target detection and tracking or for high-resolution imaging. The transducers are designed to operate at 150 kHz to cover a distance of about 200 mm and with featured narrow vertical directivity and wide horizontal directivity to scan an almost plane section with a linear array configuration.

Usually, an energy harvester must be connected to a power management circuit that performs different functions: AC/DC conversion, DC/DC conversion, energy storage, and/or battery charging. In this paper, a comparison between power management circuits connected to a specific electromagnetic generator is presented. In particular, three different power management circuits have been simulated: three-step Villard circuit, three-step Cockcroft–Walton circuit, and two-step Cascode circuit. From the simulation results, the Villard circuit is the most efficient circuit for the considered electromagnetic harvester; hence, experimental measurements with this circuit have been performed.

An RF harvesting system and power management architectural strategy for autonomous ultra-low-power system is presented. In this work a particular attention is given at the antenna/rectifier structure showing the main achieved results in this field; moreover, the measurement of an assigned RF power density in the utilized frequency range is also presented. The designed rectenna takes advantage from a balanced structure, allowing a full-wave rectification with only two diodes. The compactness of the used antenna allows it to be integrated in small devices area.

This work presents a novel wireless and low-power platform based on low-cost MEMS (microelectromechanical system) sensors to be used for motion tracking and navigation systems. Biomedical and rehabilitation purposes as well as gaming and consumer electronics may be the potential applications. The paper aims to describe the hardware architecture, the embedded sensor fusion algorithm providing real-time orientation of the platform, and the performance with respect to the state-of-the-art solutions.

Piezoelectric oxide semiconductor field effect transistor (i.e. POSFET) sensor is a class of piezoelectric semiconductor devices which has been proposed for tactile sensing. As these sensors have piezoelectric material on top of the NMOS transistor gate, their bias point behaviour became a matter of speculation for a designer. Therefore, while biasing such sensors, one should take into account the technological spread and the combination of capacitances contributed by the piezoelectric material and the MOSFET. In our work, we will highlight the above issues and then propose a novel approach to fix the bias point of the sensor. Our results are based on the measurement and parameter extractions in a real case. This will give reasons behind the variation in bias points which is commonly observed on the sensors in a chip.

This work presents a Qi standard compliant wireless power charger system, made of a wireless power transmitter and a wireless power receiver. The developed system aims to be compliant with the latest revision of Wireless Power Consortium’s directives and uses a full-bridge resonant inverter as the main power transmitter architecture. The wireless power transmitter and receiver have been designed with ultra-low-power and high-efficiency electronic components, thereby maximizing the overall power transfer efficiency.

This work reports preliminary results of characterization of a new optical ceramics-based device for application to Medium Voltage (MV) substations. These optical ceramics, which are based on Kerr effect, offer advantages of high sensitivity to electrical field together with a low cost for the device. Preliminary tests were successfully carried out on a commercially available device using these optical ceramics; it was suitably designed as a synchronization system for MV switchboard.

The incidence of CVD in population is dramatically increasing, due to the world population ageing and to obesity. Advanced home care technologies seem to be the solutions to face this trend controlling the health budgets. In this scenario, silicon manufacturers recently started to develop miniaturized system on chip dedicated to ECG, performing high-accuracy measurements, with low-power consumption. The present paper deals with a novel IC named ReISC3, developed by STMicroelectronics for low-power biopotentials acquisition and processing. Such a system has been characterized and preliminary ECGs were measured, dealing also with the processing aspects.

This paper introduces a novel gas sensor platform for use in biometric and environmental monitoring applications. The sensor is constituted of a multilayer thin film structure deposited on polyimide flexible substrate, allowing its use in disposable and low-cost applications. The sensing technique is based on dielectric and thermal spectroscopy. A differential layout allows an active polymer and a reference to be used. The combination of these techniques should enhance sensing capabilities, with higher gas sensitivity and immunity to interfering inputs.

Two novel fully analog interfaces, based on a modified De Sauty bridge configuration, for the automatic estimation of grounded wide-range capacitive sensors, are proposed here. These solutions aim to maintain the same simple topologies as that of a traditional bridge but with the advantage of performing a continuous equilibrium condition, without the need of any initial calibration procedure, thanks to the employment of an AD633-based voltage-controlled resistance combined with a suitable feedback loop which forces the bridge to work in a new steady-state situation. Thus, with respect to traditional AC bridges, the proposed interfaces can easily estimate larger capacitance variations, useful when sensor capacitance baseline is not well known. The work proposed here shows the basic principle idea, thanks to which it is possible to estimate 1.6 decades of capacitance variations (25–840 nF) with a quite reduced relative error, and its extended version which can reveal and quantify more than three decades of capacitive variations (900 pF–1.1 μF) with a more reduced error estimation.

A new analog lock-in amplifier for automatic measurements of very small and noisy signals is proposed here. The integrated system, which is particularly suitable for the accurate detection in sensor applications, performs continuously the relative phase alignment and the frequency tuning of input and reference signals through automatic operations ensured by suitable feedbacks. The complete structure of this amplifier has been implemented both as a PCB, with discrete commercial components, and as an ASIC, fabricated in AMS 0.35 μm standard CMOS technology. The system has been optimized to operate in the operating frequency range (2.5 ÷ 25) Hz, so resulting suitable for different sensor applications. Conducted measurements, also employing commercial resistive gas sensors for the ethylene glycol revelation, have demonstrated the system validity and its satisfactory performances in the detection of noisy signal amplitudes, also down to tens of nV. Moreover, with respect to a simpler resistive voltage divider, typically used as a basic sensor interface, the resolution improvement provided by the proposed lock-in allows a theoretical concentration detection in the order of tens of ppb.

This work proposes and experimentally validates a piezoelectric vibration energy harvester, which exploits the impact of a central compliant driving beam onto two piezoelectric parallel bimorph beams on flexible steel. At suitable mechanical excitation conditions, the central driving beam impacts the piezo beams and triggers a nonlinear frequency-up conversion mechanism that improves the overall effectiveness, i.e. increases the overall rms output voltage and widens the equivalent bandwidth of the converter, with respect to the linear condition of the noninteracting beams.

A low-cost interface circuit, suitable for both electrochemical and semiconductor sensors for gas detection, is described. The proposed solution offers a wide range of measurement, as well as high sampling rate, on the order of 25 ms, thus facilitating the monitoring of the sensor behavior in the presence of fast transients. The presented front end has a 3.3 V single-supply and a time-coded digital signal output; thus, it is suitable to be directly interfaced to, or integrated with, a microcontroller for the management of the measurement process. Experimental results, conducted using a discrete component prototype and sample resistors emulating the sensor, have shown a maximum linearity error in the estimation of the sensor current or resistance of about 5 % over a measurement range of seven decades, with a maximum measurement time of 25 ms. Further tests with real sensors have confirmed the capability of the front end of acquiring fast sensor transients, thus demonstrating the validity of the proposed approach.

This article proposes the implementation of a method for modeling hysteresis loops and related losses in magnetic core inductors used for power converters applications. The method has been applied to some commercially available ferrite materials in order to verify the accordance of B–H loops and power losses density estimation with acceptable results. Once correctly calibrated, the model could help to characterize magnetic materials hysteresis losses and to optimize the inductor core material choice and dimensioning in high-power density converters design.

This work proposes and experimentally validates a vibration energy harvester which combines the multi-frequency and nonlinear approaches into a converter array. The converter array consists of four piezoelectric cantilevers composed of ferromagnetic substrates with screen-printed lead zirconate titanate (PZT) layers coupled with a single permanent magnet spring suspended on the array base in order to create a nonlinear behavior. The presence of the moving magnet and the possibility to fabricate cantilevers with different potential curves can be useful to obtain a collective nonlinear behavior due to strong coupling irrespective of the amplitude of the mechanical excitation, therefore increasing the overall effectiveness of the converter array. The experimental results confirm that combining cantilevers with different potential curves can be useful to obtain a collective bistable behavior, therefore increasing the overall effectiveness of the converter array.

The field of structural health monitoring is an area of great interest, especially in Italy, in the light of recent tragic earthquakes that have struck. This has resulted in an increased attention to the WSN research in view of the possible deployment of networks for structural monitoring of individual buildings or entire areas of interest. Generally this technology is still characterized by lack of standardization with different architectural and technological solution coexisting in the same building. For this reason it would be of great interest to collect, harmonize and use data from different types of monitoring networks. ENEA with consortium T.R.E. in the

Provaci

project is involved in the development of an architecture for the fusion of data from WSN for SHM, based on different platforms and technologies.

A simple, portable, and low-cost system for noninvasive measurement of vital parameters, based on two sensors conveniently combined in a unique compact-in-size and low-power structure, has been presented and characterized in this work. The proposed solution allows both sensors to fit in a small structure, in order to be applied on the earlobe (or analogue body part of a person) in a clip-like fashion, making it suitable for portable and battery-operated systems. The two involved sensors are as follows: a photoplethysmographic (PPG) sensor, used to optically measure the change in volume of blood in the arteries, thus to acquire information about heart beating, and a sensor composed by two electrodes, used to perform an impedance measurement, thus to monitor the dielectric properties of biological tissues and fluids, like blood flow.

In the last years, energy saving is one of the dominant themes of public opinion, and thus the technological research is focused on this topic. The only adoption of new and more efficient technologies does not solve problem of the losses introduced by the carriage gas or water. In all countries, the losses of water in waterworks and in the urban carriage networks are great, but this problem is particularly acute in Italy, where, for example, the water losses overtake 30 % of the total amount of the water flowing in pipes. In the following, a solution based on WSN for the monitoring of the leakages, mainly in gas pipe, using the wM-Bus communication technology, has been proposed.

In this paper, the development and validation of a shield prototype for resistive sensor array characterization with Arduino UNO, a platform based on ATmega328 microcontroller provided by ATMEL, is reported. The resistance variation of the sensor can be evaluated by properly choosing the capacitance value and by measuring the period (frequency) of a custom inverter-based oscillator. The GUI and the developed firmware are able to perform the real-time monitoring of the sensor responses. The developed shield is able to measure the response of up to six sensors under UV radiation by means of LED devices. First results carried out with resistive sensors based on mesoporous In

2

O

3

-based material under UV light exposure are reported.

In this paper a study of an innovative energy-harvesting system based on a piezoelectric converter to recover energy from an airflow is presented. The converter is embedded as a part of an oscillating beam, and it is used to harvest energy from the vibrations induced by von Karman vortices detached from a bluff body placed upstream. The system has been placed in a wind tunnel in order to measure the converter voltage and the harvested power for different flow velocities and beam orientations with respect to the flow direction. Experimental results confirm the von Karman vortices as the forcing for the beam oscillations. The possibility to optimize the harvesting effectiveness with the proper beam orientation and flow velocity has been demonstrated.

The paper proposes a mobile measurement system for the real-time monitoring of environmental pollutions in urban areas. The proposed approach is based on the use of a set of vehicles, typically employed for public transportation inside the urban area, equipped with the proposed mobile measurement system. The system is able to measure, store, and transmit the acquired pollution data to a remote supervisor unit during the path followed by the vehicle. The experimental measurement campaign performed on a suitable urban scenario has confirmed the goodness of the proposed system.

The paper presents the development of a compact system able to measure sweat pH, by means of a functionalized textile and a color sensor, and the skin temperature. The aim is to achieve a wearable miniaturized system capable to estimate the body hydration level during exercise or a heat stress. Potential users span from elderly, first responders to athletes. The system has been characterized in the laboratory by using buffer solution, artificial sweat, and an oven for temperature sensor calibrations. Preliminary on-body trials are also reported in the final part of the paper.

Nowadays, the matter of uncertainty in face recognition-based biometric systems is a relevant issue for the scientific community. This is due to the even more increasing deployment of such systems in critical applications such as safety, security, and access control, to cite a few. In this context, the authors are engaged in the design of general methods for uncertainty modeling and evaluation aimed at realizing face recognition-based biometric systems with built-in uncertainty evaluation capability. In this way, the output of a recognition system will not be the identity of the observed subject, but a confidence level for each possible subject. In previous papers the authors have identified the quantities of influence and have proposed a suitable uncertainty model. The core of the proposed model is the knowledge of the value assumed by the quantities of influence with respect to the corresponding values achieved in suitable reference conditions. This paper mainly analyzes these measurement issues, a fundamental step toward the development of such systems with built-in uncertainty evaluation capability. First results show a good agreement between statistical indicators and a priori estimations achieved with the proposed method.

The respiratory rate is an important biomedical parameter to monitor human physical condition and investigate potential respiratory dysfunctions. The pulmonary plethysmography (PP) is a technique for measuring changes in tidal volume during the respiratory activity. The PP often requires intrusive and invasive devices that are not comfortable, as masks or mouthpieces. In the literature, there are less invasive techniques available for respiration measurement based on woven conductive yarns and metal electrodes (Paradiso et al. Proc. 25th Ann. Int. Conf. IEEE EMBS 4:3720–3723, 2003; Yang et al. 2012 IEEE-EMBS International Conference on Biomedical and Health Informatics (BHI):875–877, 2012; Maarsingh et al. J Appl Physiol 88:1955–1961, 2000; Di Rienzo et al. Proc. 27th Ann. Int. Conf. IEEE EMBS:7167–7169, 2005). In this paper, a sensor measuring the respiratory rate was implemented by screen printing (serigraphy) of the piezoresistive material on T-shirt directly. The printed pastes have produced a flexible thick film in order to measure horizontal stretching movement of the T-shirt. A circuit the amplitude impedance modulus variation close to a resonance condition was implemented. The experimental results show a maximal amplitude sensitivity of about −5.18 Ω/cm.

In aeronautic industry, an important step towards an energy-efficient aircraft is the use of composite materials (carbon-fibre-reinforced plastics, CFRP) showing excellent mechanical properties combined with low specific weight. Since assembly and maintenance of CFRP aircraft components are preferably to be performed by adhesive bonding, it is critical for in-field quality assessment (QA) procedures to check for surface contaminations by aeronautic fluids (e.g. hydraulic and de-icing fluids, release agent, water) that may eventually affect the bond strength and robustness. To this aim, any non-destructive testing (NDT) techniques have not been yet validated for ensuring the quality of the bonds.

The aerospace industry and several frameworks of public international research are devising significant financial resources to promote the development of energy-efficient aircraft transport. ENEA UTTP/MDB is involved in two international cooperations financed by EU in the framework of ENCOMB project (extended non-destructive testing of composite bonds quality assessment) and of ICARO project (in-field CFRP surface contamination assessment by an artificial olfaction tool). ENCOMB is an FP7 project that specifically addresses the research for new NDT techniques that could be used for the quality assessment of CFRP panel adhesive bonding, while ICARO project has the aim to develop an artificial olfaction tool as a suitable NDT technique capable to implement a specific detection of contaminant traces on CFRP surfaces and prevent damage or failures.

The MEPhI’s Department of Nano- and Microelectronics was founded in 1965. In 1996, the Department of Nano- and Microelectronics created the first laboratory prototypes of IMS devices. ELNOS (electronic nose) research laboratory has been created since 1999 to develop ion-mobility spectrometry (IMS) technique for detection of ultrasmall amount of substances. During this time, considerable experience in the research and development of IMS was acquired. The four main focuses of application for developed IMS device were detection of explosives (TNT, PETN, RDX, TATP, NG, EGDN, and others), identification of narcotics (heroin, cocaine, amphetamine, methamphetamine, tetrahydrocannabinol, and others), carrying out rescue operations (searching of peoples under destroyed buildings by detection of lactic acid), and diagnostic of human illness (noninvasive detection of diabetes, lung cancer by breath test). For the development of devices for such versatile applications, we need to combine knowledge in the field of chemistry, physics, electronics, programming, and nonstandard microelectronics technology (thick film, ceramic, and MEMS technologies). The synthesis of this knowledge has allowed the ELNOS laboratory in the last 10 years to develop commercially successful samples of IMS devices.

A novel fiber-optic flow sensor has been developed for monitoring inspiratory efforts during neonatal mechanical ventilation. The considered sensor is based on fiber-optic sensing techniques, allowing the reduction of the effects due to electromagnetic interferences and a possible improvement of the electrical safety conditions. In the arrangement described here, the fiber-optic sensor is able to measure, with an accuracy of 5 %, flow variations in the range between 0.5 l/min and 5 l/min that are the typical flow variations due to infants’ inspiratory attempts and typical flow trigger levels set during assist-control ventilation (ACV). Moreover, a good agreement (

r

2

= 0.998) between experimental data and the parabolic theoretical model can be deduced. The metrological characteristics confirm that the novel proposed configuration for the optical fiber air flow sensor is suitable for monitoring flow variations due to infants’ inspiratory attempts.

The food industry is continuously looking for reliable methods useful to standardize different control parameters and has a direct interest into bitter‐tasting substances, either for the identification of negative off‐flavors or for the monitoring of a desired organoleptic quality. The exploitation of dedicated panel tests for sensory purposes is useful, but it suffers from limitations related to subjectivity, reproducibility, and number of analysis per day (Profile Attribute Analysis). On the contrary, sophisticated analytical solutions, such as HPLC, need trained personnel and are often too expensive or time consuming. The target of the present research work is the development of alternative techniques potentially able to detect taste molecular markers in bakery commodities, with particular attention to polyphenol detection. In particular, two different analytical approaches were developed and compared to a reference LC-MS protocol in order to detect the polyphenol concentration inside real food matrices like biscuits: FT-NIR and electroanalytical methods.

Civet coffee is recognized as the world’s most expensive “gourmet” coffee due to its unique taste and aroma. In this work a concrete and promising approach to the headspace profile aroma attributes of Philippine civet coffee using electronic nose (EN) and gas chromatography–mass spectrometry (GC-MS) with SPME techniques was investigated. Chemometric pattern technique was applied to improve the discrimination of civet coffee against its control coffee beans (not eaten by civet animal). EN analysis has shown that aroma characteristic is one of the most important quality indicators of civet coffee. The result was supported by classical chemical techniques like GC-MS analysis with SPME. The chromatographic fingerprints indicated that civet coffees varied with their control beans in terms of composition and concentration of individual volatile constituents (qualitative and quantitative differences). Chemometric discrimination of EN and GC-MS data demonstrated a clearly separated civet from their control coffees, indicating that cultivar and geographic origins decree the aroma and volatile variations in coffee.

Drinking water treatment is needed for providing water that is safe from disease-causing pathogenic microorganisms. Chlorine is widely used as a disinfectant in drinking water systems, although the main disadvantages are the decay of its concentration along the pipes and the formation of undesirable by-products (DBPs). In this research work, the chlorine decay process has been investigated along a real water distribution system, the Santa Sofia aqueduct (Campania, Southern Italy), by an innovative modeling approach. The adopted hydraulic and water quality models have been calibrated on

live data

(the physical/chemical characteristics of the drinking water) and gathered continuously by a wireless network of multi-parametric probes distributed along the Santa Sofia aqueduct. The residual chlorine concentrations throughout the Santa Sofia network, predicted by hydraulic and water quality models calibrated on the same aqueduct, may be considered reliable.

Drinking water chlorination reduces the risk of pathogenic infection, but it may be harmful to human health because of disinfection by-product (DBP) formation. Available predictive models of DBP formation are almost exclusively calibrated at lab scale. The objective of the present research work is to apply two of them at full scale for the Santa Sofia aqueduct (Campania, Southern Italy), in order to predict DBP formation and evolution as function of the real water network characteristics.

Live

data, gathered continuously by a wireless network of multi-parametric probes, installed on the aqueduct, along with data measured in laboratory, are used for model calibration. The predictive scenarios are performed by using an open source integrated GIS-based platform (including Epanet, MSX, GIS uDig).

In this paper the development of an electronic nose for biomedical applications is reported. The key concept guiding the development of the analyzer has been the portability, its easy use, and interface with the patient and hospital facilities. With this in mind, a small analyzer with an e-nose, comprising commercial gas sensors and a breath sampling device, was assembled and tested. After the calibration tests carried out in laboratory, the real-time breath monitoring of patients under hemodialysis treatment has been performed to validate the developed analyzer.