Marco Parvis

Publications

    Grassini, S.; Pisano, R.; Barresi, A.A.; Angelini, E.; Parvis, M. – Frequency domain image analysis for the characterization of porous productsMany pharmaceutical products are obtained via freeze-drying of liquid solutions to obtain stable long lasting preparations. The freeze-dry process produces porous cakes whose structure strongly depends on the freezing phase, so that monitoring and optimizing this phase can help both reducing the product cost and insuring its constant quality. Nowadays the optimization is usually performed by determining the cake mass transfer coefficient via a costly process in pilot plants, while the quality is assured only by controlling the process conditions. This paper describes an alternative way of approximately estimat-ing the mass transfer coefficient, which is based on the observation of the product structure by a simple electron microscope followed by a frequency domain imaging process. While the process has been designed and characterized specifically for pharmaceutical products, the proposed approach can be used in several other fields where the characteristics of porous material have to be monitored.

    Angelini, E; Civita, F.; Corbellini, S.; Fulginiti, D.; Giovagnoli, A.; Grassini, S.; Parvis, M. – Innovative monitoring campaign of the environmental conditions of the Stibbert museum in FlorenceConservation of ancient metallic artefact displayed inside museums is a complex problem due to the large number of constraints mainly related to the artefacts fruition by people. The development of a simple procedure for monitoring the artefact conservation state promptly highlighting risky conditions without impacting on the normal museum operations could be of interest in the cultural heritage world. This paper describes the interesting results obtained by using a highly sensitive and innovative methodology for evaluating the safety level of the museum indoor areas, and more specifically of the interior of the showcases, with respect to the metallic artefacts. The methodology is based on the use of an innovative smart sensors network and of copper reference samples. The smart sensors network was employed for the continuous monitoring of temperature and relative humidity close to the artefacts, i.e. inside the display showcases. The reference specimens were Cu coated with a 100 nm Cu nanostructured layer put for 1 year in the exhibition rooms inside and outside the showcases and characterised by means of normal imaging, colorimetric and FESEM techniques at regular intervals. The results of the monitoring activity evidenced the higher reactivity to the environmental aggressivity of the nanocoated copper specimen

    Grassini, S.; Corbellini, S.; Parvis, M; Angelini, E.; Zucchi, F. – A simple Arduino-based EIS system for in situ corrosion monitoring of metallic works of artMetallic artifacts of archaeological and historical interest, exposed outdoor, can be severely affected by degradation due to the exposure to aggressive agents present in the surrounding environment. Development of suitable preventing conservation strategies for these important witnesses of our culture, requires to investigate their corrosion behavior in order to understand the electrochemical phenomena occurring on the metallic surface. This investigation can be easily performed in laboratory by means of different chemico-physical techniques, which provide information about composition, microstructure and morphology of the corrosion products, as well as by means of electrochemical measurements, which allow estimating the corrosion resistance of the metal. Unfortunately, these measurements are often invasive and require microsampling. Electrochemical Impedance Spectroscopy (EIS), thanks to the high sensitivity and to the small perturbation applied to the corroding system, can be considered a useful non-destructive testing method to obtain valuable information on the conservation state of metallic works of art. This paper describes an innovative portable, low-cost and user-friendly solution for EIS in situ measurements, based on the widely diffused Arduino board and on a specially designed measuring probes. The proposed solution cannot provide the complete knowledge of the corrosion mechanisms occurring onto the metallic surface, but can be an extremely useful tool for conservators and art historians for the assessment and long-time monitoring of the artifacts stability

    Sabrina Grassini;Maen Ishtaiwi;Marco Parvis;Alberto Vallan – Design and Deployment of Low-Cost Plastic Optical Fiber Sensors for Gas MonitoringThis paper describes an approach to develop and deploy low-cost plasti optical fiber sensors suitable for measuring low concentrations of pollutants in the atmosphere. The sensors are designed by depositing onto the exposed core of a plastic fiber thin films of sensitive compounds via either plasma sputtering or via plasma-enhanced chemical vapor deposition (PECVD). The interaction between the deposited layer and the gas alters the fiber's capability to transmit the light, so that the sensor can simply be realized with a few centimeters of fiber, an LED and a photodiode. Sensors arranged in this way exhibit several advantages in comparison to electrochemical and optical conventional sensors; in particular, they have an extremely low cost and can be easily designed to have an integral, i.e., cumulative, response. The paper describes the sensor design, the preparation procedure and two examples of sensor prototypes that exploit a cumulative response. One sensor is designed for monitoring indoor atmospheres for cultural heritage applications and the other for detecting the presence of particular gas species inside the RPC (resistive plate chamber) muon detector of the Compact Muon Solenoid (CMS) experiment at CERN in Geneva

    Sabrina Grassini; Simone Corbellini; Emma Angelini; Franco Ferraris; Marco Parvis – Low-Cost Impedance Spectroscopy System Based on a Logarithmic AmplifierImpedance spectroscopy (IS) involves measurements of impedance amplitudes, which often span more than six/seven decades. Currently available IS systems employ sophisticate front-ends to cope with this wide impedance range and, consequently, the cost of the measuring instrument greatly increases. This paper describes an alternative low-cost solution, which is based on a logarithmic front-end and on an off-the-shelf microcontroller board. Using these components, the cost remains below $100, while still having the capability of measuring over a frequency range of 0.01 Hz-100 kHz and for impedance values in the range of 100 Ω - 10 GΩ. The overall uncertainty remains below 5% of amplitude and few degrees of phase. The proposed system is, therefore, suitable for electrochemical impedance spectroscopy applications, as well as for bioelectrical impedance analysis

    Grassini, S.; Angelini, E.; Pisano, R.; Barresi, A; Parvis, M. – Wavelet image decomposition for characterization of freeze-dried pharmaceutical product structuresThis paper investigates the use of a wavelet image decomposition applied to electron microscope images in order to estimate the mass transfer coefficient of pharmaceutical cakes obtained by freeze-drying. The structure analysis of dried cakes obtained by means of a free-drying process, is a basic step for tuning the process conditions and for monitoring the quality of the dried product. The product structure and specifically its porosity affects the drying duration as it defines the resistance to the vapor flow during the ice sublimation. This parameter is becoming quite important as it is fundamental for modeling of the freeze-drying process and thus for an optimal design of the freeze-drying cycle. The direct measurement of this parameter is quite complex thus new simple approaches are being developed for its non-invasive estimation. This paper discusses the possibility of processing SEM images of the dried cake to analyze its morphology and to estimate the mass transfer coefficient. This approach has already been followed by processing the images via a 2D-FFT, here a faster solution based on the image wavelet decomposition followed by a non-linear processing based on an artificial neural network is described and the results are compared with the one obtained by the traditional direct mass transfer coefficient measurement

    Emma Angelini;Simone Corbellini;Marco Parvis;Franco Ferraris;Sabrina Grassini – An Arduino-based EIS with a logarithmic amplifier for corrosion monitoringElectrochemical Impedance Spectroscopy (EIS) is an interesting non-invasive technique to study the corrosion layer of metallic artifacts as well as to test the integrity of protective coatings, however commercial EIS systems are rather expensive devices. This paper describes an extremely low cost realization of an EIS system that is based on a simple commercial Arduino Board whose cost is below 50$. The instrument is able to perform impedance measurements in the range 1 k to 1 G, thanks to a specifically designed front end based on a logarithmic amplifier, and in the frequency range of 0.01 Hz to 100 kHz. The instrument can work as a stand-Alone device or connected to a PC. The required current is of about 100 mA, thus, the USB port of a common laptop can power the instrument for several hours without external supply. It is also possible to employ several instruments at the same time for a massive parallel measurement campaign with a negligible cost. The instrument accuracy is of about 2% for impedances in the range of 1 k to 100 M, with uncertainty on the phase of about 2°

    Parvis M.; Grassini S.; Angelini E.; Pisano R.; Barresi A. – Characterization of freeze-dried pharmaceutical product structures by an FFT-imaging approachThis paper describes an imaging-based approach for the characterization of the pharmaceutical product structures obtained by freeze-drying. The analysis of the dried cake structure and particularly the estimation of its porosity and permeability, is fundamental for the selection of the optimal process conditions and also for the product quality control. Furthermore, the product structure has a dramatic impact on the drying behavior as it determines the resistance offered by the dried product to the vapor flow generated by the ice sublimation. This parameter, that allows one to relate sublimation rate to partial pressure gradients, is gaining growing importance in recent years, as it is necessary for the application of the most modern model-based methods for the design of the freeze-drying cycle. This parameter is difficult to be measured so new measuring approaches are required to make its estimation easier. In this study a bi-dimensional Fourier analysis is used for image processing of the internal structure of lyophilised samples and, then, for the estimation of their mass transfer coefficient

    Angelini E.; Assante D.; Grassini S.; Parvis M. – EIS measurements for the assessment of the conservation state of metallic works of artThe in-situ conservation of metallic artefacts of artistic and historic interest is a scientific challenge. The characterization of surface conditions of the artefacts is mandatory to estimate the effect of the atmospheric corrosion on the metal. Electrochemical impedance spectroscopy (EIS) is a technique that can be employed in order to investigate the phenomena involved at the electrochemical interfaces and to predict the corrosion process. In this paper, a portable instrument specifically realized for EIS measurements on metallic works of art is presented, and the measurement results on two case studies are discussed: the iron bar chains in the Notre Dame Cathedral in Amiens (France) and a large weathering steel monument exposed outdoor in Ferrara

    Sabrina Grassini;Emma Angelini;Marco Parvis;Simone Corbellini;Maen Ishtaiwi – Electrochemical characterization of magnesium bioabsorbable implants2014 IEEE International Symposium on Medical Measurements and Applications (MeMeA)The bone surgery often makes use of implants to sustain and fix the bones during the healing phase. Commonly used implants require a surgical procedure to be removed after bone healing, so there is a strong demand for a new typology of bio-absorbable implants. Magnesium and its alloys are promising materials for orthopedic self-degrading implants, mainly if they are protected by a thin coating. The design of Mg-based implants cannot disregard the adoption of a simple measurement procedure for assessing and monitoring the corrosion evolution in environments simulating the body fluids. This paper describes a measuring approach for the corrosion behavior assessment of different Mg-based alloys uncoated and coated with innovative surface treatments, based on Electrochemical Impedance Spectroscopy measurements

    Alberto Vallan; Maria Luisa Casalicchio; Renato Orta; Marco Parvis; Guido Perrone – Low-Cost Fiber Sensors for Displacement and Vibration MonitoringThe paper presents some fiber optic sensors that have been devised to provide a low-cost solution to monitor mechanical quantities, such as displacement, vibration amplitude and acceleration, in applications where fire safety or electromagnetic immunity are of primary concern. The proposed sensors are based on plastic optical fibers and require simplified interrogation systems since they relate the quantity under measurement with changes in the received optical power. Both contact and non-contact sensors have been developed in order to cover a vast range of applications

    Barresi A.A.; Baldi G; Parvis M; Vallan A; Velardi S; Hammouri H – Optimization and control of the freeze-drying process of pharmaceutical productsA system is described for monitoring the lyophilisation process of a product in containers (4, 4a, 4b) arranged inside a lyophilisation chamber, comprising a temperature measurement system (6) associated with each container housed inside (10) said lyophilisation chamber, capable of surveying local temperature data for each container. The system includes: a wireless communication system (8) for the surveyed temperature data; and a processing module (16) for said data, located externally to the lyophilisation chamber, programmed to determine at least one parameter indicative of the progress of the lyophilisation process not measured by the measurement system, by means of a predetermined representation model of the process, capable of correlating a local temperature value of the container with said parameter

    Grassini S.; Fulginiti D.; Pisano R.; Oddone I. ; Parvis M. – Real-time temperature monitoring in pharmaceutical freeze-dryingIn this study, a thermocouple array realized by using thin film strips is employed for real-time temperature measurements during pharmaceutical freeze-drying. The thin film thermocouple array is directly deposited on the vial walls and can be employed to monitor the temperature evolution during the freezing stage. Freezing is a critical stage of the entire cycle, since the nucleation temperature influences the morphology of the dried material and, consequently, the subsequent drying phase. Since conventional thermocouples are too invasive, due to the high thermal conductivity of the metallic wires, which alter the product nucleation, innovative measuring approaches have to be developed and validated to optimize the drying cycles. Moreover, conventional thermocouples allow only one-point measurement to be obtained, while the possibility of realizing thermocouple arrays offered by the thin film technology, can give more reliable results

    Parvis M.; Grassini S.; Fulginiti D. ; Pisano R.; Barresi A.A. – Sputtered thermocouple array for vial temperature mappingThis paper describes the development and characterization of a thin film thermocouple array to be used as a non-invasive solution to map the temperature distribution inside small vials used for freeze-drying pharmaceutical chemicals. Pharmaceutical chemicals are often produced by means of freeze-dryers with very good results, even though the slowness of drying process may increase the product cost. Increasing the shelf temperature accelerates the drying process, but can increase the risk of melting and damaging the product. This risk could be minimized by following the product temperature evolution during the drying step, by means of a noninvasive measuring system able to perform an in situ continuous monitoring. Actual sensors are too invasive to permit a reliable measurement and in addition their dimension does not allow to employ many sensors in a small volume. This paper describes the development of a new multi-sensor structure based on an array of thermocouples having nanometric thickness. The thermocouple array can be embedded into the glass wall of a test vial having all the other characteristics equal to the remaining batch thus providing meaningful and reliable results. Prototypes of the proposed thermocouple array have already been realized and tested making it possible to map the temperature at intervals of few millimeters, following the ice edge during lyophilization

    Emma Angelini;Sabrina Grassini;Marco Parvis;Marco Prioli;Simona Salicone – An application of the Random-Fuzzy variables for the safeguard of underwater cultural heritageThis paper applies the Theory of Evidence and the Random-Fuzzy variables for monitoring the conservation state of metallic works of art in seawater. Cathodic protection can be proposed as a low invasive approach for the in situ preservation of underwater metallic artifacts. By measuring, at different times, the cathodic current and the corrosion potential of the artifact and by taking into account their measurement uncertainties, the Random-Fuzzy variables allow one to provide a risk level indicating a failure in the protection system. The evaluation of the risk level is very important, since the underwater artifact is not handy and the complex underwater environment can significantly affect the stability of the artifact. The monitoring of the risk level allows to highlight in real time possible dangerous situations for the artifact and an appropriate intervention can be promptly implemented

    Parvis, M.; Ferraris, F.; Grassini, S.; Angelini, E.; Fulginiti, D. – Biodegradable metallic materials: A measuring approach to predict the corrosion rateThis paper describes the development and characterization of thermocouples with nanometric thickness made inert by means of a glass-like coating. These thermocouples are designed to follow the freeze-drying process of pharmaceutical products without perturbing freezing and drying steps but can be used in several other applications where the perturbation introduced by wire thermocouples can prevent a correct measurement to be performed. The developed thermocouples are T-type with a thickness in the range of 50-200 nm and are embedded into the vial wall owing to a SiO2-like coating with a glass-like structure and a thickness of 200 nm. This way, they actually measure the product temperature without altering thermal distribution and shape of the drying front and without modifying the cake structure during the freezing step, so that the results can be extended to the other not instrumented vials. The SiO2-like coating ensures that no ion exchange takes place between thermocouple metals and lyophilized product, thus avoiding the risk of contamination and denaturation. The extremely low thickness requires a preliminary characterization of the thermocouples in order to determine their Seebeck coefficient, but the sealing provided by the coating, which prevents oxidization and degradation of the metallic strips, ensures that the obtained coefficients can be used for a long time

    Grassini S.; Parvis M.; Barresi A.A. – Inert thermocouple with nanometric thickness for lyophilization monitoringThis paper describes the development and characterization of thermocouples with nanometric thickness made inert by means of a glass-like coating. These thermocouples are designed to follow the freeze-drying process of pharmaceutical products without perturbing freezing and drying steps but can be used in several other applications where the perturbation introduced by wire thermocouples can prevent a correct measurement to be performed. The developed thermocouples are T-type with a thickness in the range of 50-200 nm and are embedded into the vial wall owing to a SiO2-like coating with a glass-like structure and a thickness of 200 nm. This way, they actually measure the product temperature without altering thermal distribution and shape of the drying front and withoutmodifying the cake structure during the freezing step, so that the results can be extended to the other not instrumented vials. The SiO2-like coating ensures that no ion exchange takes place between thermocouple metals and lyophilized product, thus avoiding the risk of contamination and denaturation. The extremely low thickness requires a preliminary characterization of the thermocouples in order to determine their Seebeck coefficient, but the sealing provided by the coating, which prevents oxidization and degradation of the metallic strips, ensures that the obtained coefficients can be used for a long time

    Sabrina Grassini; Marco Parvis; Marie Bouchar; Philippe Dillmann; Delphine Neff – Integrated measuring approach for the study of corrosion mechanismsThe study of the corrosion mechanisms which affect iron artifacts is the first fundamental step for developing tailored and long-lasting conservation procedures. Unfortunately, such mechanisms are connected not only to the composition of the corrosion product layer, but also to its porosity and micro-structure. μ-Raman spectroscopy can be used to assess the composition of the corrosion products, but the effect of the layer porosity requires a different approach. This paper investigates the combined use of μ-Raman and Electrochemical Impedance Spectroscopy (EIS) for the characterization of some iron reinforcements of the Metz Cathedral (France), with the final goals of understanding the corrosion mechanism and having a reliable assessment of the artifact stability. In particular, the proposed measuring approach has proved to be able to give useful data on the electrochemical reactivity of the surface, on the presence of cracks and on the porosity degree of the corrosion product layers. After a series of laboratory tests to characterize the surface, the EIS measurements can be employed also in-situ for a noninvasive assessment of the artifact corrosion behavior. This way it is possible to conceive long-lasting monitoring campaigns, which would allow one to identify artifacts apparently well-preserved, but in danger of possible corrosion due to the porous nature of their corrosion layers and the presence of active electrochemical species in contact to the metallic surface

    Parvis M. – Issues in environmental monitoring of metallic heritage artefactsThis chapter attemps to address monitoring problems from a wider point of view that is usual in the cultural heritage field. It discusses the issues connected to variations of space and time in the measured quantities. Some differently structured systems which can be employed in designing a monitoring infrastructure are discussed and a case study is reported to illustrate the practical application of general guidelines

    Grassini S; Angelini E; Parvis M; Bouchar M; Dillmann P; Neff D – An in situ corrosion study of Middle Ages wrought iron bar chains in the Amiens CathedralThe corrosion behaviour of Middle Ages wrought iron bar chains exposed to indoor atmospheric corrosion for hundred of years in the Notre Dame Cathedral of Amiens (France) has been evaluated by means of Electrochemical Impedance Spectroscopy (EIS), a well-established electrochemical technique extensively used for testing anticorrosive properties of metal coatings. The measurements have been performed in situ with a portable EIS instrument designed to work as a standalone device, in six different areas of the wrought iron bar chains characterized by different aesthetical appearance. Moreover, a properly designed electrochemical cell has been employed to carry out the impedance measurements without affecting the artefacts surfaces. The wrought iron bar chains, as evidenced by μ-Raman and microscopic analyses, are covered by corrosion products constituted by iron oxides and oxyhydroxides, such as goethite, lepidocrocite, maghemite, akaganeite, organized in complex layered structures. In situ EIS allows one to investigate the phenomena involved at the electrochemical interfaces among the various corrosion products and to assess and predict their corrosion behaviour. From the analysis of the experimental findings of this monitoring campaign, EIS measurements can be proposed to restorers/conservators as a reliable indicator of dangerous situations on which they must act for the preservation of the iron artefacts

    Grassini S. ; Ishtaiwi M.; Parvis M.; Benussi L.; Bianco S.; Colafranceschi S.; Piccolo D. – Gas monitoring in RPC by means of non-invasive plasma coated POF sensorsResistive Plate Counters (RPC) are employed as muon detectors in many high-rate high-energy physics experiments, such as the Compact Muon Solenoid (CMS) experiment currently under way in the Large Hadron Collider (LHC) accelerator at the European Center for Nuclear Research (CERN). A gas mixture containing C2H2F4, i-C4H 10 and SF6 is recirculated inside the RPCs during their use and subjected to degradation due to the production of fluoride ions which limits the sensitivity of the RPCs. This paper describes a new sensor that is able to detect low concentrations of fluoride ions in gas mixtures. The sensor is made of a plastic optic fiber (POF) which is made sensitive to F- gaseous ions by means of a thin layer of a glass-like material, deposited via plasma onto the fiber core. The F- ions attack the glass-like film and alter the transmission capability of the fiber so that the detection simply requires a LED and a photodiode. The sensor exploits a cumulative response which makes it suitable for direct estimation of the total exposure to the F - ions, thus providing a tool that can be used to tune the maintenance of the gas filters. The glass-like film is deposited by means of plasma enhanced chemical vapor deposition (PECVD) of organosilicons monomers, which allows the deposition to be performed a low temperature in order to avoid damaging the fiber core

    Ferraris F.; Parvis M.; Angelini E.; Grassini S. – Measuring system for enhanced cathodic corrosion protectionBuried metallic artifacts in soil or seawater are exposed to high risk of corrosion due to the contact with the surrounding aggressive environment. The protection of a wide range of iron-based artifacts is carried out by means of cathodic protection (CP)systems. CP is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell, through the connection of the metal to be protected with another more easily corroded "sacrificial metal" acting as the anode of the electrochemical cell. Cathodic protection is an efficient solution, however the sacrificial anodes need to be replaced regularly. This paper describes the design and development of a measuring system able to continuously monitor the object protection state maintaining it in safe conditions. The proposed system embeds a controller which is able to adjust the sacrificial anode current, thus increasing its life while keeping its protecting effect. The device is powered by a small lithium battery whose duration can be easily extended to several years making it longer than the sacrificial anodes duration. The proposed device is designed to be employed underwater for the protection of the metallic parts of a surveillance system developed for the protection and fruition of an underwater archeological site in the South of Italy

    Corbellini S.; Parvis M.; Grassini S.; Benussi L.; Bianco S.; Colafranceschi S.; Piccolo D. – Modified POF Sensor for Gaseous Hydrogen Fluoride Monitoring in the Presence of Ionizing RadiationsThis paper describes the development of a sensor designed to detect low concentrations of hydrogen fluoride (HF) in gas mixtures. The sensor employs a plastic optical fiber (POF) covered with a thin layer of glass- like material. HF attacks the glass and alters the fiber transmission capability so that the detection simply requires a LED and a photodiode. The coated POF is obtained by means of low-pressure plasma-enhanced chemical vapor deposition that allows the glass-like film to be deposited at low temperature without damaging the fiber core. The developed sensor will be installed in the recirculation gas system of the resistive plate chamber muon detector of the Compact Muon Solenoid experiment at the Large Hadron Collider accelerator of the European Organization for Nuclear Research (CERN)

    Corbellini S.; Parvis M.; Grassini S. – Noninvasive Solution for Electrochemical Impedance Spectroscopy on Metallic Works of ArtMetallic works of art of cultural relevance are continuously subjected to corrosion as the environment becomes increasingly polluted. A fast and simple method to in situ assess the conservation conditions is therefore required. This paper describes the development and performance of dry and gel-based electrodes which can be used to assess the surface conservation state without the need to move the artifacts and which do not cause any damage to them. The electrodes can be used with a portable electrochemical impedance spectroscopy system, without employing electrochemical cells. The proposed solution does not provide all the information that one can obtain using an electrochemical cell, but it can discriminate between protective coatings. It can be used to assess the protective capability of corrosion product layers and natural patinas, and it can therefore enable a noninvasive routine surface assessment to be conducted that could be extremely useful for people working in the field of conservation of cultural heritage

    Barresi A., Baldi G., Parvis M., Vallan A., Velardi S., Hammouri H. – Optimization and control of the freeze-drying process of pharmaceutical products

    Grassini S., Ishtaiwi M., Parvis M., Benussi L.,Bianco S., Colafrancesci S., Piccolo D. – SiOx coated plastic fiber optic sensor for gas monitoring in RPCThis paper describes the development of a sensor designed to monitor the closed loop recirculation gas system of the Resistive Plate Counter (RPC) muon detectors which are used for the Compact Muon Solenoid (CMS) experiment installed at the Large Hadron Collider (LHC) accelerator of the European Center for Nuclear Research (CERN). The sensor is designed to detect low concentrations of hydrogen fluoride (HF) in the gas mixtures and employs a plastic optic fiber (POF) which is covered with a thin layer of a glass-like material. The fluorine ions attacks the glass and alters the fiber transmission capability so that the detection simply requires a LED and a photodiode. The coating is obtained by means of a low pressure plasma enhanced chemical vapor deposition (PECVD) that allows the glass-like film to be deposited at low temperature without damaging the fiber core

    Bosca S., Barresi A.A., Fissore D., Grassini S., Parvis M., Vallan A., Corbellini S. – "Smart Vial": a simple and effective device to monitor a freeze-drying process in laboratory and in industrial apparatus

    Parvis M.; Grassini S.; Barresi A.A. – Sputtered Thermocouple for Lyophilization MonitoringThis paper describes development and characterization of thin film thermocouples to be used as a non-perturbating solution to follow the freeze-drying process of pharmaceutical chemicals. Pharmaceutical chemicals are routinely produced by means of freeze-dryers with excellent results, however the drying process is slow requiring days to complete and this increases the product cost. To optimize the process, reducing the drying time, this must be carried out close to the maximum allowed temperature. A monitoring system able to continuously monitor the product temperature during the drying could greatly reduce the damage risk, but actual sensors are too invasive to permit a reliable measurement and radiation remote systems cannot be used. This paper describes the results obtained by developing thermocouples with sub-micrometric thickness which can be embedded into the vial walls without significatively altering the wall thickness and properties. Prototypes of the proposed thermocou- ples have been realized and successfully tested

    S. Grassini; E. Angelini; M. Parvis; F. Faraldi – Surface modification plasma treatments of PMMA optical fibres for sensing applicationsPlasma deposited thin films are very promising for the development of innovative gas sensors based on plastic optical fibres (POF). POFs exploit the evanescent field interaction, so that the sensors can be produced by depositing a sensing thin film onto the fibre surface and measuring the light transmittance change because of its reaction with the gas. A standard, low-cost, commercial step-index, highly multimode POF was used to set up cumulative sensor prototypes to detect H2S vapours in low concentration. The approach proposed for the realization of the sensors foresees the surface modification of the plastic optic fibre in two steps: (1) etching of the cladding by means of ethyl-acetate and (2) deposition of an Ag nanostructured sensing film by plasma sputtering. The study of the gas diffusion/reaction process occurring onto the fibre surface is a fundamental step to arrange simple and low-cost devices characterized by high sensitivity and high selectivity towards the gas of interest. This process depends on many parameters connected to the sensing layer chemistry and morphology and are, consequently, complex and difficult to predict. The POF-based approach was employed also for monitoring the gas diffusion/reaction process through the sensing layer to model the process itself and to understand how it can affect the expected sensor response

    Angelini E.; Grassini S.; Parvis M.; Zucchi F. – An in situ investigation of the corrosion behaviour of a weathering steel work of artAn in situ investigation of the atmospheric corrosion phenomena affecting weathering steels has been performed on a large outdoor sculpture dated back to 1983, the 'Reditus ad origines' by Agapito Miniucchi. The sculpture is exposed in the Scientific and Technological Pole of the University of Ferrara, and is an interesting example of architectural recovery of an industrial area. The assessment of the corrosion behavior was performed by means of an in situ, nondestructive approach based on electrochemical impedance spectroscopy measurements. The ultimate goal is to understand the corrosion mechanisms that affect outdoor immovable metallic artefacts to develop tailored and long-lasting conservation strategies. The impedance measurements were carried out by means of a portable equipment specifically designed by the authors to work as a stand-alone device connected to a personal computer. Polymeric electrodes were employed instead of the traditional electrochemical cell to avoid any acceleration of the corrosion process; the applied stimulus was in the range 0.001Hz-100kHz, while the measurement range could span from about 100Ω to 1GΩ. Furthermore, chemical analyses were carried out by means of X-ray photoelectron spectroscopy on samples obtained with a microsampling technique to correlate the electrochemical impedance spectroscopy results with the chemical composition of the corrosion layer and to identify the presence of electrochemically active species

    A. Carullo, M.L. Casalicchio, F. Ferraris , M. Olivero , M. Parvis, A. Penna, G. Perrone, A. Vallan – Compensazione delle variazioni di potenza ottica per sensori infibra ottica plastica a variazione di intensità

    Corbellini S.; Parvis M.; Grassini S. – Development and characterization of flexible electrodes for protective painting monitoringThe assessment of the protective capabilities of thin films is usually performed by means of Electrochemical Impedance Spectroscopy (EIS) and accelerated aging tests in aggressive environments. Typical EIS tests are performed either using electrochemical cells whose electrolytic solutions irreversibly damage the coating or metallic sputtered electrodes which cannot be removed after the measurement. This paper describes a solution that does not employ either chemical solutions or sputtered or mercury electrodes and therefore does not damage the coating and does not pose health hazards. The proposed solution is based on the use of soft rubber electrodes, coated by a thin gold layer. Such electrodes overcome the problems of following the small surface irregularities that would prevent the correct estimation of the contact surface in the case of rigid electrodes. The use of soft electrodes requires a suitable modeling to take the electrode surface roughness into account as a function of the electrode contact pressure. The paper describes the soft electrode development and their modeling and characterization by comparison with mercury and metallic electrodes sputtered onto the surface

    Corbellini S.; Ferraris F.; Neri A.; Parvis M.; Angelini E.; Grassini S. – Exposure-Tolerant Imaging Solution forCultural Heritage MonitoringThis paper describes a simple and cheap solution specifically designed for monitoring the degradation of thin coatings employed for metal protection. The proposed solution employs a commercial photocamera and a frequency-domain-based approach that is capable of highlighting the surface uniformity changes due to initial corrosion. Even though the proposed solution is specifically designed to monitor the long-time performance of protective coatings employed for the restoration of silver artifacts, it can be successfully used also for assessing the conservation state of other ancient metallic works of art. The proposed solution is made tolerant to exposure changes by using a procedure for sensor nonlinearity identification and correction, does not require a precise lighting control, and employs only free open-source software, so that its overall cost is very low and can be used also by not specifically trained operators

    Grassini S., Corbellini S., Neff D., Dillmann P., Parvis M., Angelini E. – Misure d'impedenza elettrochimica per lo studio dei fenomeni di corrosione atmosferica di strutture in ferro d'nteresse artisticoI meccanismi di corrosione atmosferica di lungo periodo che interessano le strutture in ferro d'interesse storico-artistico sono stati studiati mediante spettroscopia d'impedenza elettrochimica (EIS). In particolare l'impiego di uno strumento portatile, progettato e realizzato dagli autori, ha permesso di effettuare una campagna di misure in situ su alcuni manufatti in ferro esposti all'interno della cattedrale Notre-Dame di Amiens (Francia), esposta da più di 500 anni alla corrosione atmosferica. Le misure d'impedenza elettrochimica, condotte parallelamente ad una caratterizzazione chimica, morfologica e microstrutturale, possono fornire interessanti informazioni sul meccanismo di degrado, sul comportamento dei diversi composti, essenzialmente miscele di ossidi ed idrossidi di ferro, quali goethite, lepidocrocite, akaganeite, maghemite, ecc, nei confronti del fenomeno corrosivo, sulla presenza di difetti e zone elettrochimicamente attive. In questo modo è possibile prevedere il comportamento a corrosione del manufatto, permettendo ai restauratori la messa a punto di metodologie di restauro specifiche, efficaci e durature

    Corbellini S.; Grassini S.; Parvis M.; Benussi L.; Bianco S.; Colafranceschi S.; Piccolo D. – POF sensors for gas monitoring in the presence of ionizing radiationsThis paper describes an innovative sensor for the measurement of low concentrations of hydrogen fluoride (HF) in the insulating gas employed in resistive plate chamber detectors (RPC). RPC detectors are widely used in high energy physics experiments to detect the presence of muons. This application is designed to be installed at the Large Hadron Collider at CERN (European Center for Nuclear Research) and is based on a plastic optic fiber. The sensor is capable of working in the presence of ionizing radiation for periods in excess of 6 months with excellent performance and without transmission lost. The sensitivity to the HF is obtained by deposing a thin SiO x layer onto the fiber core. The reaction of such layer with the HF alters the fiber light transmission and is revealed by a photodiode

    Grassini S., Corbellini S., Neff D., Dillmann P., Parvis M. , Angelini E. – The iron artefacts of the Amiens Cathedral: in situ EIS measuring campaign for the assessment of the corrosion behaviourConservation of ferrous artefacts in heritage buildings requires the characterization of the corrosion products in order to understand the atmospheric corrosion mechanisms and to develop tailored, long lasting conservation methodologies. In this study, the corrosion products grown on several iron artefacts exposed to over 500 years in the Amiens Cathedral have been studied by means of electrochemical impedance spectroscopy (EIS). The artefacts, subjected to long time indoor atmos-pheric corrosion, are coated by corrosion products constituted by iron oxides and oxy-hydroxides, such as goethite, lepidocrocite, maghemite, akaganeite, organised in a very complex structure. In situ EIS has been employed to investigate the phenom-ena involved at the electrochemical interfaces among the various corrosion products and to assess and predict their corrosion behaviour. The measurements have been performed by means of a portable EIS analyser specifically designed to work as a stand-alone device, all over a frequency range from 0.001 Hz to 40 kHz and for impedances in the range of 1 kļ— - 10 Gļ—. Adhesive and flexible probes with conduc-tive gel have been employed to carry out the impedance measurements without af-fecting the rust layers and the metal surface. The EIS data have been compared with the microchemical and microstructural characterisations of the layers

    A. Braglia, A. Carullo, F. Ferraris, A. Neri, M. Olivero, R. Orta, M. Parvis, G. Perrone, D. Tosi, A. Vallan – CARATTERIZZAZIONE DI COMPONENTI PER LASER DI POTENZA IN FIBRA OTTICA

    Ferri A.; Corbellini S.; Parvis M.; Splendore R. – Compact RF sensors for monitoring thermo-physiological comfort of sportswear

    Corbellini S; Parvis M; Grassini S.; Piantanida M, Consalvi F; Gigante G; Meddi F; – Electrical Tomography for the Monitoring of Water Moisture in Painted Walls and CeilingsPainted walls represent a great heritage of cultural and artistic value. Unfortunately, these works of art, especially the frescos, are constantly attacked by moisture and salt content in the wall plaster, thus, particular attention has to be paid on their conservation state. Nevertheless, there are no many instruments that permit to detect the wall state without causing damages to the paintings. For these reasons, a non-invasive measuring system, which is based on resistivity measurements, is proposed to investigate the moisture content in painted walls and ceilings. The method is able to provide information not only at the wall surface but also at few centimeters beneath the painting, thus allowing one to detect dangerous situations before the deteriorating effects take place. Despite the attention has been focused on the conservation of work of arts, the proposed system can be employed in many other fields including the building sector in general

    Angelini E; Grassini S.; Piantanida M; Corbellini S; Ferraris F; Neri A; Parvis M – FFT-based imaging processing for cultural heritage monitoringConservation of precious metallic works of art requires an in situ monitoring of the conditions of the objects and of the protecting coatings employed for their restoration. In this paper a simple diagnostic tool based on digital photography and 2D-FFT imaging processing is proposed that is used for monitoring the corrosion process occurring on metal surfaces. The proposed approach has been tested in laboratory on a set of silver reference samples which have been coated with SiOx thin films deposited via plasma and submitted to a tarnishing test. The obtained results show that the proposed technique permits to overcome most of the problems usually encountered when using conventional image processing based on amplitude and colors that require maintaining standard lighting and artifacts conditions, that are not easily achievable in museums. Although the proposed solution is not able to provide details about protective coating failure and the corrosion mechanism, its results can be correlated to the tarnishing susceptibility and, therefore, this technique can be use to assess the stability of the artifacts and to put in evidence the beginning of dangerous localized corrosion phenomena, that require immediate restoration

    Angelini E., Grassini S., Mombello D., Neri A., Parvis M. – AN IMAGING APPROACH FOR A CONTACTLESS MONITORING OF THE CONSERVATION STATE OF METALLIC WORKS OF ARTAn easy-to-use and cheap diagnostic tool based on digital photography and 2D-FFT imaging processing is described that can be used to monitor the corrosion process occurring over time on the surface of metallic works of art in indoor and outdoor environments and to assess the stability of the materials employed for restoration. The proposed solution has the advantage of not requiring standard lighting and artifacts manipulation, that are not easily achievable in real applications. The imaging algorithm is capable of highlighting the changes in the surface uniformity due to the corrosion process and can be used to put in evidence the beginning of dangerous localized corrosion phenomena onto the metallic surface. Although this technique does not allow a quantitative measurement of the corrosion rate, it has proved to be an effective approach to assess the stability of protective coatings. The proposed processing has been tested in laboratory to asses the stability of SiO2-like protective coatings deposited by PECVD on a set of silver reference alloys submitted to a tarnishing test in the presence of H2S vapors

    S. Corbellini; M. Parvis; A. Vallan – In-Process Temperature Mapping System for Industrial Freeze DryersThis paper describes a low-invasive temperature mapping system specially designed for vacuum and non accessibleenvironments, such as industrial freeze dryers. Thermal resistances tend to become quite hight in vacuum since convection is absent and even very small gaps have extremely conductive resistances. Temperature monitoring in the vacuum therefore requires sensors that do not inject power to minimize the self-heating and a special attention to the effect due to the involved thermal resistances. The proposed solution employs small autonomous measuring nodes that use a wireless connection to transmit the results and that are characterized to correct the thermal constant effect during temperature changes. The system has been designed for the monitoring of large freeze dryers, but its characteristics make it useful in many other vacuum conditions. The system is capable of monitoring the temperature of hundreds of points with an uncertainty of the order of a degree and with a cost per point of a few euros

    Angelini E.; Grassini S.; Corbellini S.; Parvis M.; Piantanida M. – A MULTIDISCIPLINARY APPROACH FOR THE CONSERVATION OF A BUILDING OF THE SEVENTEENTH CENTURYA long-term multidisciplinary conservation study is actually in progress inside the Villa della Regina, a prestigious Savoy residence built in the seventeenth century and recently restored. The walls of some rooms of the Villa are decorated with precious tin-mercury mirrors, that are baked with a reflective coating constituted of a tin-mercury compound surrounded by liquid mercury. The reflective layer is very soft, thus any restoration is difficult to be performed and can lead to a complete destruction of the artifact. Amalgam corrosion is a very slow process and, although there is no way to prevent the oxidation of the reflective layer, the conservation state of the artifacts may be improved by keeping them in a controlled environment. For this reason, a monitoring system has been designed and installed that is based on a wireless network of extremely compact sensors, for temperature and relative humidity measurements. The sensors have been specifically designed to satisfy the requirements for use in cultural heritage field and the system allows one to automatically collect the data that can be analyzed with the final aim to establish a correlation between the environmental conditions and the conservation state of the artifacts. A restoration has been carried out by producing in situ an amalgam inlay on the corroded area to slow down the release of liquid mercury in order to avoid also possible unsafe conditions for staff and visitors. In addition, a sensor has been developed which is based on a prototypical plastic optical fiber for the detection of low concentration Hg vapors to ensure the safe conditions in the Villa rooms. The sensor is being tested in laboratory

    Angelini E., Corbellini S., Grassini S., Mao Y., Mombello D., Parvis M. – Non-invasive assessment of the corrosion behaviour of metallic ar-tefacts displayed in museum showcasesPaper 9329

    Angelini E; Grassini S.; Mombello D; Piantanida M, Neri A; Parvis M; Perrone G; – An Optic Solution for the Measurement of Gas Diffusion in Thin FilmsThin films are increasingly used both for the development of innovative gas sensors and for surface protection purposes due to availability of new surface treatments, such as those based on low pressure and atmospheric plasma processes. In many cases sequential treatments are required, where, after the initial deposition, the film is exposed to different chemical compounds that both react and diffuse inside the film, usually to enhance its properties. These reaction/diffusion processes depend on many parameters connected to the layer morphology and are, therefore, complex and difficult to preview. Several authors have studied the problem and have developed powerful mathematical models, whose validation, however, is difficult since making measurements during the transient process, especially for films with nanometric thickness, is not easy. In this paper, the authors investigate two optical solutions that can be applied to many practical cases to follow the diffusion process of gases in real time and thus tune and validate the models. The first solution is based on the well-known Surface Plasmon Resonance (SPR) phenomenon and allows precise evaluations to be obtained, but requires a lab-type setup. The other solution employs a Plastic Optical Fiber (POF) and exploits the evanescent field interaction to arrange a simple and cheap setup, that can be used also for in situ tests. Both approaches are applied to the study of the diffusion of sulfide vapors in silver with subsequent surface tarnishing, a topic that represents a practical case of relevant importance in the field of cultural heritage preservation

    Angelini E; Grassini S; Mombello D; Neri A.; Parvis M; Perrone G – PLASMA MODIFIED POF SENSORS FOR IN SITU ENVIRONMENTAL MONITORING OF MUSEUM INDOOR ENVIRONMENTSA cumulative sensor for in situ monitoring of H2S vapors in museum showcases based on plastic optical fiber (POF) has been developed. H 2S is responsible for the tarnishing of silver artifacts, so monitoring their total exposure over time to sulfide rich atmospheres can help in choosing the correct display procedure and, consequently, lead to improvements in their conservation. The sensor working principle is based on the modulation of the guided light intensity following a chemical reaction between a thin silver layer deposited onto the fiber core and the sulfide compounds to be detected. The proposed approach for the sensor fabrication requires the optimization of a two-step process: (1) etching of the fiber cladding to expose the core; (2) plasma deposition of a silver thin film onto the PMMA core. Silver was chosen as the sensitive element, since in the presence of H2S, it starts reacting immediately and loses its brightness with time proportionally to the concentration of the aggressive gas. Some prototypes of the proposed sensing system have been produced and tested in laboratory demonstrating the capability to detect H2S at concentrations of few part-per-billion (ppb)

    Casalicchio M.L., Neri A., Parvis M., Penna A., Perrone G., Vallan A., Grassini S., Mombello D. – POF SENSOR FOR SULFIDE VAPOR MONITORING

    Carullo A. , Casalicchio M.L., Corbellini S., Ferraris F., Neri A., Parvis M., Perrone G., Vallan A., Grassini S., Angelini E., Mombello D. – SVILUPPO DI SENSORI IN FIBRA OTTICA PLASTICA PER LA MISURAZIONE DI GRANDEZZE MECCANICHE E CHIMICHE

    A. Carullo, F. Ferraris, A. Neri, M. Parvis, A. Vallan – SVILUPPO E GESTIONE IN QUALITÀ DEL SISTEMA DI MONITORAGGIO DI UN IMPIANTO FOTOVOLTAICO

    Angelini E., Grassini S., Parvis M. – Silver artefacts: plasma deposition of SiOx protective layers and tarnishing evolution assessmentSilver artifacts suffer tarnishing when exposed to a sulphur containg atmosphere. Plasma deposited SiO x thin films are proposed for the protection of silver artefacts, owing to their optical transparency and high barrier properties against vapours. The protective effectiveness of the SiO x films was assessed by means of electrochemical impedance measurements performed in an Na 2S solution on a set of coated silver based alloy samples, and by submitting another set of samples to a tarnishing test in presence of H 2S vapours. The experimental findings reveal that the SiO x deposition, performed in RF plasma fed with a tetraetoxysilane/oxygen/argon mixture, produces layers with excellent barrier effects against the aggressive agents. The protective effectiveness increases if the deposition is performed at increasing input powers and at decreasing tetraethoxysilane/oxygen ratios in the feeding gas. The tarnishing evolution onto the coated surface was assessed at the microscopical and macroscopical level by means of field emission scanning electron microscopy and by an easy to use diagnostic tool based on digital photography and image processing

    Angelini E., Corbellini S., Ferraris F., Grassini S., Mao Y., Parvis M. – An impedance spectroscopy system for the in-situ assessment of the conservation state of archaeological bronzespaper 9626 - The protective effectiveness of bronze patinas can be evaluated using electrochemical impedance spectroscopy (EIS). However, EIS, a well-established method to investigate metal coatings for general purposes, requires to perform the measurement in an electrolytic solution that may alter the surface of an artefact of archaeological or artistic interest, furthermore the need of evaluating and monitoring the conservation state of irremovable artefacts, is not satisfied by the widely employed EIS laboratory instruments. In this work, a portable impedance spectroscopy analyzer equipped with a specially designed dry- probe, that avoids the use of the electrolyte, is proposed for the evaluation of the protective effectiveness of surface layers of metallic cultural heritage artefacts. The overall system has been tested on different kinds of patinas, synthetized from sulphate and nitrate solutions on a Cu-Sn alloy, with the ultimate goal of establishing a procedure for the in situ assessment of bronzes of archaeological and artistic interest. The protective effectiveness of bronze patinas can be evaluated using electrochemical impedance spectroscopy (EIS). However, EIS, a well-established method to investigate metal coatings for general purposes, requires to perform the measurement in an electrolytic solution that may alter the surface of an artefact of archaeological or artistic interest, furthermore the need of evaluating and monitoring the conservation state of irremovable artefacts, is not satisfied by the widely employed EIS laboratory instruments. In this work, a portable impedance spectroscopy analyzer equipped with a specially designed dry- probe, that avoids the use of the electrolyte, is proposed for the evaluation of the protective effectiveness of surface layers of metallic cultural heritage artefacts. The overall system has been tested on different kinds of patinas, synthetized from sulphate and nitrate solutions on a Cu-Sn alloy, with the ultimate goal of establishing a procedure for the in situ assessment of bronzes of archaeological and artistic interest

    Neri A; Corbellini S; Parvis M; Arcudi L; Grassini S.; Piantanida M; Angelini E – Environmental Monitoring of Heritage BuildingsA system for the monitoring of microclimate and air pollutant concentrations in heritage buildings has been developed and validated by means of a measurements campaign in the Villa della Regina, a Savoy residence in Torino. The in situ campaign is currently in progress in cooperation with the Soprintendenza per i Beni Storici, Artistici ed Etnoantropologici del Piemonte. The monitoring system is composed of a wireless network of smart buttons, specifically designed to satisfy the requirements for applications in the field of cultural heritage. The smart button sensors are configured to measure temperature and humidity. Some sensor prototypes equipped also with a POF sensor for the detection of Hg vapors have been developed and are being tested in laboratory

    Neri A.; M. Parvis; G. Perrone; S. Grassini; E. Angelini; D. Mombello – Low-cost H2S gas sensor based on plastic optical fiberA new simple and low-cost fiber optic sensor for cumulative detection of H2S and other sulphide compounds is described. The transducer is based on a plastic optical fiber and exploits a non-reversible chemical reaction, whose products interact with the evanescent field tails thus increasing the propagation losses with the exposure time. The sensor has a sensitivity of the order of few ppb

    Carullo A.; Grassini S.; Parvis M. – Measurement Procedures for the Electrical Characterization of Oxide Thin FilmsThis paper describes a measurement system for the electrical characterization of oxide thin films. Such films can be produced using plasma-sputtering processes and permit the realization of a large set of high-performance components, such as capacitors, active devices, sensors, and protective coatings. The electrical properties of the oxide films, which have a thickness of less than 1 μm, are difficult to measure since very high resistances (on the order of gigaohms) and small capacitances (on the order of picofarads) are expected for contact areas smaller than 1 mm2. The measurement system and the procedures described in this paper represent an alternative solution to the commercial devices, which usually employ a mercury probe for performing the contact with the specimen under characterization. Furthermore, the proposed system can be used not only to estimate the electrical properties of a single point but to evaluate the uniformity of oxide films on large specimens as well. The experimental results reported refer to valve-metal-based oxide films deposited in a lab-scale capacitively coupled parallel-plate reactor and show the effectiveness of the proposed procedures

    Barresi A.A.; Pisano R.; Fissore D.; Rasetto V.; Velardi S.A.; Vallan A.; Parvis M.; Galan M. – Monitoring of the primary drying of a lyophilization process in vialsAn innovative and modular system (LyoMonitor) for monitoring the primary drying of a lyophilization process in vials is illustrated: it integrates some commercial devices (pressure gauges, moisture sensor and mass spectrometer), an innovative balance and a manometric temperature measurement system based on an improved algorithm (DPE) to estimate sublimating interface temperature and position, product temperature profile, heat and mass transfer coefficients. A soft-sensor using a multipoint wireless thermometer can also estimate the previous parameters in a large number of vials. The performances of the previous devices for the determination of the end of the primary drying are compared. Finally, all these sensors can be used for control purposes and for the optimization of the process recipe; the use of DPE in a control loop will be shown as an example

    Grassini S; Mombello D; Neri A; Parvis M; Vallan A. – Plasma deposited thermocouple for non-invasive temperature measurementThis paper describes the realization of a temperature sensor based on plasma sputtered thermocouples. The thermocouples are realized in the vacuum with quite pure materials, negligible oxydation and with low contamination thus enabling accurate measurements and are made inert by means of a thin coating of tetraethoxysilane (TEOS) that seals them. The thermocouples have an overall thickness of few hundreds of nanometers and are designed to allow non invasive, though accurate temperature measurement to be obtained in adverse conditions, such as the ones found during lyophilization processes. Lyophilization is widely employed to obtain pharmacological active powders in an economical and massive way. The lyophilization process effectiveness depends on the thermal distribution inside the lyophilizing vials: if the temperature is too low the process become extremely slow thus greatly increasing the powder cost, but if the temperature is too high a melting of the frozen substance can occur that can make the powder useless. Tuning the drying process is therefore extremely important, but such an operation is quite difficult since the temperature greatly changes inside each lyophilizing vial due to the process itself and among vials due to their position within the apparatus. A local temperature measurement would therefore be necessary, but normal temperature sensors would alter the drying local condition making the measurement incorrect and indirect measurements proved to be not reliable. The proposed solution instead is almost inert, capable of performing accurate local measurements and can be used in a variety of conditions where size and possible contamination are of importance. A sensor prototype is described and its performance compared with conventional sensors highlighting the advantages of the proposed solution

    Angelini E; Grassini S; Neri A; Parvis M.; Perrone G. – Plastic Optic Fiber Sensor for Cumulative MeasurementsSensors are typically designed to produce outputs related to the instantaneous value of the quantity of interest; however situations exist where an output related to the total, cumulative or 'integral' exposure to the quantity of interest is required. This paper describes a low-cost optical sensor for the monitoring of the total exposure to sulphide vapors exploiting a non-reversible chemical reaction and the evanescent field absorption in plastic optical fibers. The sensor is particularly suited for extensive use in cultural heritage conservation monitoring, being intrinsically safe and also quite cheap since the interrogation does not require coherent light sources and spectral analysis. Some prototypes of the proposed sensing system have been produced and tested in laboratory, obtaining a good sensitivity and a fast response

    E. Angelini; A. Carullo; F. Ferraris; S. Grassini; D. Mombello; Neri A.; M. Parvis; A. Vallan – SVILUPPO DI SENSORI BASATI SU FILM SOTTILI NANOSTRUTTURATI DEPOSITATI VIA PLASMA

    Casalicchio M.L.; Carullo A; Corbellini S; Ferraris F; Neri A; Parvis M; Perrone G; Tosi D; Vallan A; Angelini E; Grassini S – SVILUPPO DI SENSORI IN FIBRA OTTICA PLASTICAPER GRANDEZZE MECCANICHE E CHIMICHE

    S. Grassini, D. Mombello; E. Angelini; Neri A.; M. Parvis – Strati protettivi ottenuti mediante PECVD su termocoppie per misure non invasive di temperatura

    A. Carullo; S. Corbellini; F. Ferraris; A. Luoni; Neri A.; M. Parvis; A. Vallan – TARATURA DI STRUMENTI E SISTEMI MEDIANTETECNICHE REMOTE ED AUTOMATICHE

    Carullo A; Corbellini S; Parvis M; Vallan A. – A Wireless Sensor Network for Cold-Chain MonitoringThis paper deals with a wireless sensor network that was specifically designed to monitor temperature-sensitive products during their distribution with the aim of conforming to the cold-chain assurance requirements. The measurement problems and the constraints that have been encountered in this application are initially highlighted, and then, an architecture that takes such problems into account is proposed. The proposed architecture is based on specifically designed measuring nodes that are inserted into the products to identify their behavior under real operating conditions, e.g., during a typical distribution. Such product nodes communicate through a wireless channel with a base station, which collects and processes the data sent by all the nodes. A peculiarity of the product nodes is the low cost, which allows the information on the cold-chain integrity to be provided to the final customer. The results that refer to the functional tests of the proposed system and to the experimental tests performed on a refrigerated vehicle during a distribution are reported

    Corbellini S.; Parvis M.; Vallan A. – A low-invasive system for local temperature mapping in large freeze dryersThis paper deals with low-invasive temperature monitoring inside freeze dryers. During lyophilization, both the temperature of the freeze-dryer shelves and the temperature of the products have to be measured in order to control the process and to guarantee the product quality. In addition, temperature measurements are essential to obtain reliable information during the development of the freeze-drying receipt and to scale-up the process from the laboratory to the industrial scale. Unfortunately, many constrains make such measurements extremely difficult and not many measuring systems are available; in the paper the main problems related to the temperature measurements, along with some available solutions, are discussed. Then, a low invasive measurement system, that has been specifically developed to measure both the required temperatures, is presented and described

    Carullo A; Corbellini S; Grassini S.; Parvis M – Development and analysis of procedures for the measurement of electrical properties of thin insulator layersThis paper describes a measurement system for the characterization of the electrical properties of thin insulator layers. Such layers are typical of Metal Oxide Metal (MOM) devices which can be produced by means of plasma sputtering and that permit the realization of a large set of high performance components (capacitors, active devices, sensors,...). The electrical properties of the oxide layers, which have thickness down to 100nm, are difficult to be measured since very high resistances of tens gigaohms and small capacitances of few picofarads are expected in the case of sample dimension of few square millimiters. The measurement system and the procedures described in this paper represent a possible solution for this kind of measurements and can be used to characterize not only the electrical properties of a single point, but also the uniformity and repeatability of the coating process on larger samples

    Neri A; Parvis M; Perrone G; Grassini S.; Angelini E; Mombello D – Low-cost fiber optic H2S gas sensorIn this paper the realization and characterization of a new plastic optical fiber sensor for the detection of H2S and other sulfide compounds is described. The sensor is specifically tailored for applications in cultural heritage preservation, where the capability to evaluate the total exposure even to small quantities of pollutants is required. The substitution of plastic for glass optical fibers accounts for the possibility of having all the advantages of a fiber-based device, while lowering the cost of the final device and furthermore improving the sensitivity for evanescent field sensing. The transducer exploits the variation of the optical absorption of Ag when exposed to the sulfide atmosphere and is fabricated by a preliminary chemical etching of the cladding in ethyl-acetate, followed by deposition of the Ag thin film by plasma sputtering. Some sensors prototypes have been developed and tested in a climatic chamber to assess their response in the presence of sulfide vapors. In addition chemical orphological characterization of the plastic fibers have been carried out by means of infrared spectroscopy and scanning electron microscopy. The prototypes exposed to H2S have shown a very fast response achieving a 90% decay in the transmitted power in 900 seconds upon exposure to a 0.1 M H2S solution;such a decay has been found to be nearly wavelength independent,and is correlated to the transformation of the metallic Ag into Ag2S

    Carullo A; Corbellini S; Parvis M.; Reyneri L; Vallan A – A Measuring System for the Assurance of the Cold-Chain IntegrityThis work deals with a measuring system that is specifically designedfor monitoring temperature-sensitive goods during their distribution, with the aim to conform to the cold-chain assurance requirements. The measurement problems and the constraints that are met in this application are initially highlighted, then an architecture is proposed that takes such problems into account. The proposed architecture is based on measuring nodes that are integrated into the goods, in order to identify their behavior in real operating conditions, e.g. during a typical distribution path. The measuring nodes communicates through a wireless channel with a base station, that plays the role of data concentrator and processing unit. Preliminary experimental results have been obtained that have shown the feasibility of the proposed solution and that have provided useful information for the design of the whole system

    Neri A.; M. Parvis; G. Perrone; S. Grassini; E. Angelini; D. Mombello – SVILUPPO DI SENSORI DI GAS IN FIBRA OTTICA POLIMERICA

    Carullo A; Ferraris F; Parvis M; Perrone G.; Vallan A – Sensori in fibra ottica plastica per il monitoraggio strutturale

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis – Sistemi di misura per il monitoraggio della catena del freddo

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis – Sviluppo di procedure per la caratterizzazione elettrica di film sottili isolanti

    Corbellini S; Ferraris F; Parvis M. – A System for Monitoring Workers' Safety in an Unhealthy Environment by means of Wearable SensorsThis paper describes a system for monitoring the safety of workers who are exposed to unhealthy environments. The system is based on a low-cost wireless network of smart wearable buttons that can be applied inside the protective suits and that embed the measurement device along with a 2.4 GHz radio. The proposed solution is conceived to be employed with elements that use textile fibres as intrinsic sensors and with discrete sensors as well. The network allows both the measurement strategy and the program code of the wearable sensors to be remotely updated in order to adapt and optimize the power consumption. The real-time operability is also permitted by introducing proxy elements that allow the network area to be extended in a solution similar to that of the Zigbee but optimized for the required architecture. The system can be employed in a wide class of indoor medical applications; an example is provided that is intended to monitor temperature and humidity for workers inside refrigerated chambers

    Carullo A.; Parvis M; Vallan A – A grid architecture for efficient measurements of electrical disturbanceThis paper deals with the extension of the Grid paradigm to distributed measuring systems. The main problems that arise when distributed measuring systems are configured as Grid are discussed and a solution is also proposed in order to integrate measuring nodes with low processing capabilities in a Grid architecture. The problem that is mainly discussed in the paper is that related to the configuration of the Grid that allows good performance to be obtained in terms of processing time. An example application is developed that is a system for measuring conducted disturbances of electrical equipments, which is based on a parallel processing algorithm. A Grid architecture has been deployed in order to implement the proposed algorithm and a specific service has been developed, whose task is the choice of the processing strategy that minimize the total processing time. Experimental results are also provided that refer to a real scenario

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis; A. Vallan – Calibratore di gas per la taratura a distanzadi stazioni di misura dell'inquinamento ambientale

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis; A. Vallan – Campione viaggiatore per la taratura a distanzadi sistemi di monitoraggio dell'inquinamento ambientale

    Cacciatore V; Corbellini S; Parvis M.; Vallan A – Conducted disturbance measurement system based on a GRID architectureThanks to the recent GRID technologies growth, in more research and industrial environments it is possible to obtain a number of benefits about the resources availability that could be shared in a fully trusted net architecture. GRID frameworks allow users to discover, monitor and control distributed resources on the net and to develop dedicated services for cooperative elaboration as well. This paper describes the design and realization of a GRID-based measurement system for assessing the electromagnetic conducted disturbances. In such a context, the GRID allows the access to remote acquisition nodes and implements an algorithm studied for pre-compliance analysis that takes advantage of the overall GRID. This kind of structure is useful in laboratories where a cluster for intensive data elaboration is not available

    Vallan, A; Parvis, M; Barresi, A.A; Rasetto, V. – Developing and testing of a new balance for monitoring lyophilization in vials

    Carullo A; Corbellini S; Ferraris F; Parvis M.; Vallan A – Integration of low computational power nodes in a GRID measurement architectureThe increasing diffusion of environmental monitoring systems demands for more flexibility in the management of the whole system and in a lower cost for the arrangement of each measuring unit. Both these requirements can be met by arranging the whole system as a GRID architecture and employing units that are based on low-cost micro-controllers or palm PCs. However, such kind of units does not exhibit enough processing capabilities to met the full GRID requirements. For this reason, the authors propose a proxybased approach that allows low-cost measuring units to be integrated into a GRID architecture, by introducing the concept of virtual measurement GRID node. Such a node is mainly composed of a measurement front-end that communicates with a proxy GRID node, which exhibits the full GRID services. An example of virtual measurement node is proposed that is conceived for pollution monitoring and a prototype of measurement node is described that senses temperature and concentration of carbone monoxide.

    Barresi A.A.; Pisano R; Rasetto V; Velardi S; Vallan A; Parvis M; Galan M – Monitoring, control and optimisation of freeze-drying process

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis; A. Vallan – Sistemi automatici di misura per applicazioni industriali

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis; A. Vallan – Sistemi di misura basati sull'architettura distribuita GRID

    Corbellini S.; Franco Ferraris; Marco Parvis – A Cryptographic System for Brand Authentication and Material Traceability in the Textile IndustryThis paper deals with problems of brand authentication and product traceability which are recently affecting the textile market; the continuing increase in the counterfeit production of clothes is heavily revealing the lack of adequate techniques able to assure both the brand authentication of final clothes and the trustworthy of textiles involved in the intermediate manufacturing stages. The signature methods that are currently available are based either on classical labels or on sophisticated textile markers whose reliability lays on the physical irreproducibility of the mark itself These approaches are either insufficient or too costly to be actually employed; hence this paper presents a new system that is based on cryptographic techniques and which can assure the traceability of the textile during the whole manufacturing process. The proposed solution does not require costly devices, and, even though it is conceived for the textile sector, it can be employed in many other fields as well. A preliminary prototype is described and its capability of working in the presence of noise and material alterations is discussed

    A.M. Boglietti; Cavagnino A.; M. Parvis; A. Vallan – Evaluation of Radiation Thermal Resistances in Industrial MotorsThis paper deals with the role of the radiation thermal resistances in industrial motors and describes a test set useful for the resistance evaluation. The test set is based on a vacuum chamber and on a numerical acquisition system, and the resistances are obtained by monitoring motor temperatures during a heating test. An analytical model that describes how the radiation resistance depends on the motor temperature is also provided. Experimental results obtained on a totally enclosed fan-cooled 150-W induction motor are shown and discussed

    Angelini E.; Carullo A. ; Corbellini S.; Ferraris F.; Gallone V.; Grassini S.; Parvis M.; Vallan A – Handheld-Impedance-Measurement System with seven-decade capability and potentiostatic functionThis paper describes design and test of a new impedance-measurement system for nonlinear devices that exhibits a seven-decade range and works down to a frequency of 0.01 Hz. The system is specifically designed for electrochemical measurements, but the proposed architecture can be employed in many other fields where flexible signal generation and analysis are required. The system employs an unconventional signal generator based on two pulsewidth modulation (PWM) oscillators and an autocalibration system that allows uncertainties of less than 3% to be obtained over a range of 1 kΩ to 100 GΩ. A synchronous demodulation processing allows the noise superimposed to the low-amplitude input signals to be made negligible

    Corbellini S; Ferraris F; Parvis M. – Low-Cost Laser-Based Localization System for Agricultural MachinesThis paper describes the design and test of a low-cost localization system for agricultural applications, which determines a tractor position in fields up to 0.5 km with an uncertainty of about 1 m. The proposed system employs a standard unmodified laser head, which is commonly used for field leveling, plus a reference ground-fixed laser receiver and requires neither laser modulation nor expensive time-of-flight measurements of light beams

    Barresi A.A.; Baldi G; Parvis M; Vallan A; Velardi S; Hammouri H – Ottimizzazione e controllo del processo di liofilizzazione di prodotti farmaceutici

    S. Corbellini; Ferraris F.; M. Parvis – A Simulation Framework for Rapid Development of Microprocessor Based Measurement SystemsThis paper describes a framework which can be used to simplify the development of microprocessor based instruments. The framework is based on digital simulators which describe the behavior of the different blocks and a message interchange protocol which allows the simulators to communicate in order to emulate the complete measuring systems. By means of this protocol multiple simple simulators can cooperatively work in situations where microcontrollers and several digital peripherals are present and are requested to exchange digital data

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis; A. Vallan – Sistemi automatici di misura per applicazioni industriali

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis; A. Vallan – Sviluppo di campioni viaggiatori per la taratura a distanza di sistemi di monitoraggio dell'inquinamento ambientale

    Carullo A; Corbellini S; Ferraris F.; Parvis M; Vallan A – Sviluppo di campioni viaggiatori per la taratura di sistemi di misurazione distribuiti

    Carullo A; Parvis M.; Corbellini S – Traceability Assurance fo Tele-MeasurementsThis paper deals with the traceability-assurance problems that are faced when a distributed measuring system is employed. These problems are highlighted for different distributed-system architecture, then a set of guide-lines are provided in order to correctly manage such systems from a metrological point of view. The proposed solution is based on a network-assisted calibration procedure, which requires suitable traveling standards that are sent to the nodes of a distributed system under calibration and are remotely controlled through the Internet. A prototype of a traveling standard is also described that has the capability to be synchronized with standards sent to the other nodes

    Carullo A.; Ferraris F; Parvis M – Traceability Issues in Distributed Measuring SystemsThis paper deals with the traceability-assurance problems that are faced when a distributed measuring system is employed. These problems are highlighted for different distributed-system architecture, then a set of guidelines is provided in order to correctly manage such systems from a metrological point of view. The proposed solution is based on a network-assisted calibration procedure, which requires suitable travelling standards that are sent to the nodes of a distributed system under calibration and are remotely controlled through the Internet. Two prototypes of travelling standard are also described that have been designed in order to implement the proposed calibration procedure. The first prototype can be used for the calibration of system, which require tight temporal coherence, while the second one is able to calibrate measuring nodes that monitor the chemical pollution.

    Cacciatore V; Carullo A; Parvis M.; Vallan A – Uncertainty Effects of Data Compression in Measurement ApplicationsData compression algorithms are widely employed to reduce the amount of data in order to save storage space and to speed-up the data transfer. Lossy algorithms provides high compression ratio but are designed to provide good results mainly when multimedia data are processed. Aim of this paper is to analyze the behavior of commercial lossy and lossless algorithms in the presence of measurement data. The paper also describes a lossy algorithm that has been designed to provide high compression ratios with a known uncertainty level

    Boglietti A; Cavagnino A; Parvis M.; Vallan A – Evaluation of the Radiation Thermal Resistance in Industrial MotorsThis paper deals with the role of the radiation thermal resistances in industrial motors, and describes a test-set useful for the resistance evaluation. The test-set is based on a vacuum chamber and on a numerical acquisition system, and the resistances are obtained by monitoring motor temperatures during a heating test. An analytical model that describes how the radiation resistance depends on the motor temperature is also provided. Experimental results obtained on a TEFC 150 W induction motor are shown and discussed

    Carullo A.; Parvis M.; Vallan A. – A GPS-Synchronized Traveling Standard for the Calibration of Distributed Measuring SystemsThis paper deals with a traveling standard that has been specifically designed for calibrating distributed measuring systems. A core architecture is firstly proposed that provides the basic functionalities that are necessary to perform the calibration of such kind of systems. These basic functionalities are networking and processing capabilities, that allow a traveling standard to be remotely controlled, and synchronization capability among different standards, in order to stimulate the measuring sites of a distributed system with precise timing. A prototype is also described that has been developed for calibrating distributed systems that monitor the mains power-quality. The prototype is essentially an arbitrary signal generator, which provides voltage and current signals and embeds the basic capabilities of the core architecture. Preliminary experimental results are also reported that refer to metrological behavior and synchronization capability of the developed prototype.

    Corbellini S.; Franco Ferraris; Marco Parvis – Low-cost Laser-based Localization System for Agricultural MachinesIn this paper a low cost distance localization system for agricultural applications has been described. Such a system could assist farmers during the leveling process by providing them an altimetric map which can be used to dermine the best soil movement strategy. The discussed solution does not require any sort of modification to the commercial laser heads that are already commonly employed by the farmers for soil leveling. The proposed system is composed of a distance meter and of a reference laser receiver. The first component represents the most critical part of the system thus a complete prototype has been designed and tested, while the reference receiver is currently being designed. The experimental results show that the distance can be measured up to about 250 m with a maximum deviation of about 2 m. Even though these raw results seem still higher than the target accuracy of 1 m, thanks to the rather high rate of measurements the system provides, the initial requirement could still be reached by employing an averaging processes which is under development

    Angelini E; Grassini S.; Rosalbino F; Corbellini S; Parvis M – Monitoring of patinas and coatings protective effectiveness by means of a new EIS portable instrument

    Corbellini S.; Marco Parvis; Vallan A. – A Plug & Play Architecture for Low-Power Measurement SystemsAn architecture for low-power measurement systems has been designed and employed to arrange a temperature measurement system based on a transponder. The described architecture is modular and the measurement modules have hot-swap and plug&play capabilities. The architecture, therefore, is able to automatically neither identify and configure the measurement modules, so that a new module can be added to the measurement system without power down the system nor interrupt the measurement session. This is particularly useful when long measurement procedures are carried out and the user has the requirement to extend the system

    Corbellini S.; Parvis M.; Vallan A. – A Plug&Play Architecture for Low-Power Measurement SystemsThis paper describes a measurement system architecture designed to be employed in the presence of hard power-supply constraints. The architecture is based on a system controller and on a set of measurement modules connected through a multi-drop bus. The power requirements are fulfilled by means of a power management strategy so that modules are powered sequentially. The modules are composed of a measuring device, either custom-made or commercial, and of a control interface specifically designed to implement hot-swap and plus&play features. In this way, modules can be added to the measurement system also during a measurement session. The paper also describes an example of temperature measurement system based on the proposed architecture

    Vallan A.; Parvis M.; Barresi A.A. – Sistema per la misurazione in tempo reale di massa e temperatura di sostanze sottoposte a liofilizzazione

    Carullo A.; Corbellini S.; Parvis M. – Traceability Assurance of Tele-Measurements

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis; A. Vallan – Conferma metrologica di sistemi di misurazione distribuiti

    Bertocco M.; Cappellazzo S.; Corbellini S.; Parvis M.; Pegoraro P.; Vallan A. – E-learning in instrumentation and measurement coursesE-learning is the one possible evolution of traditional teaching techniques and is becoming a mature technology. Several commercial suites are available to author multimedia courses either to be distributed in physical form (e.g. on CD or DVD) or to be used on-line. However the application of these suites to the instrumentation and measurement courses and in general to courses that require students to learn the use of real devices is difficult and sometime useless. In this paper, some peculiar aspects of the instrumentation and measurement courses are discussed, focusing on the impact of e-learning techniques in laboratory activities. Practical hints coming from the authors' experience in several years of in-the-field trials are reported and discussed

    Carullo A.; Corbellini S.; Ferraris F.; Parvis M.; Vallan A.; Angelini E.; Grassini S.; Gallone V. – Hand Held Impedance Measurement System with Seven Decade Capability and Potentiostatic FunctionThis paper describes design and test of a new impedance measurement system for non-linear devices that exhibits a seven decade range and works down to a frequency of 0.01 Hz. The system is specifically designed for electrochemical measurements so that it can work with a few millivolt stimuli still compensating electrochemical voltages of several volts, but the proposed architecture can be employed in many other fields where a flexible signal generation and analysis is required. The system employs an unconventional signal generator based on two PWM oscillators and an autocalibration system that allows uncertainties of less than 3% to be obtained over a range of 1 kΩ to 100 GΩ A synchronous demodulation processing allows the noise superposed to the low amplitude of the employed signals to be made negligible. The proposed system is able to work both as a stand-alone device or in connection with a personal computer. In this latter case, thanks to the instrument internal architecture, the personal computer can set almost any parameter, has access to the raw acquired data and can implement new data processing and analyses

    Carullo A.; Parvis M.; Callegaro L. – Network-Assisted Procedure for Impedance DisseminationA new technique for disseminating impedance meusurement units from National Metrology Institutes to secondary laboratories is proposed in this paper. Such a technique takes advantage of a client-server application over the Internet and employs a commercially available impedance calibrator with computer-interfacing capabilities. The calibrator, which is employed as a traveling standard, is sent to the secondary laborarory, where the traceability transfer process toward a digital impedance meter is performed. Such a process is remotely managed through the Internet by the National Metrology Institute. which acquires the measurement results and issues the calibration certificate of the impedance meter. The proposed solution allows the impedance dissemination process to be largely simplified with respect to the traditional calibration technique, so that the traceability maintenance cost a secondary laboratory has to sustain is drastically reduced. The architecture of the developed client-server application over the Internet is described in the paper and preliminary results that are related to the characterization ofthe employed traveling standard are reported

    A. Carullo; S. Corbellini; Ferraris F.; M. Parvis; A. Vallan – Sistemi di misurazione automatici

    Carullo A.; Parvis M.; Vallan A. – A Traveling Standard for the Calibration of Data Acquisition BoardsThe large use of measurement systems based on data acquisition boards makes the traceability-chain assurance a tricky problem due to the difficulty in consistently calibrating such boards. In this paper, the authors describe a traveling standard which can be used for the calibration of many commercially available acquisition boards. By employing such a traveling standard, the calibration procedure can be remotely exercised by a calibration laboratory through the personal computer which hosts the board that has to be calibrated. In such a way, the calibration results refer to environmental, software, and hardware conditions that exactly match the board-operating conditions. Furthermore, the board unavailability time is drastically reduced, with a consequent economic advantage for the board owner. The traveling standard is based on a microcontroller which is responsible for the communication with the PC that hosts the board and for the board-stimulus generation, and on a digital multimeter, which acts as a reference standard

    Carullo A.; Ferraris F.; Parvis M.; Vallan A. – An Audio-Card Based RF Spectrum Analyzer for Educational PurposesIn this paper, a simple RF specmm analyzer based on a single frequency conversion is described. The analyzer is conceived to be employed as an educational tool for the elecfronic and measurement courses. The spectrum analyzer is composed of a board that actually perform the conversion and generates an analogue signal proportional to the spectrum and a vitual panel that takes advantage of the conversion capabilities of any PC audio-card. The complete system is a component of the Instrument Training Project (ITP), which is being developed a the Politecnico di Torino.

    Carullo A.; Parvis M.; Vallan A.; Callegaro L. – Automatic compensation system for impedance measurementThis paper deals with the realization of the four-pair terminal definition of impedance standards. A simple, though reliable, system is described that allows an automatic compensation of the voltage at the low potential port of impedance standards to be obtained. Such a system employs a commercial data acquisition board and a signal generator with adjustable-phase capability, which acts as the phase reference for the generator that feeds the impedance standard. A standard PC controls the whole system and implements the demodulation and the control algorithms. Preliminary tests have been performed in the frequency range of 50 Hz to 20 kHz with different kinds of impedance standards (resistive, inductive and capacitive), obtaining a residual voltage at the low potential port of less than 5 μV

    A. Carullo; Ferraris F.; M. Parvis; A. Vallan – Internet calibration: an innovative approach for the dissemination of the measurement units

    Carullo A.; Parvis M.; Vallan A. – Measurement of four terminal-pair impedances by means of a sine-fit based techniqueThis paper deals with an impedance measuring system that can be arranged by means of general purpose instruments usually available in most calibration laboratories, without requiring dedicated and costly devices. Impedance measurements are performed by employing a comparison technique and taking advantage of a sine-fit processing to make negligible the effect of noise and signal distortion on the obtained results. The system have been specialized for the measurement of impedances defined as four terminal-pair networks, therefore a suitable technique has been implemented in order to compensate for the voltages at the impedance low-potential ports. Both measuring and compensation processes are automatically managed by means of a personal computer, thus giving the possibility to remotely exercise the calibration of impedance standards through the Internet. Preliminary results are described in the paper, which have shown the functionality of the whole system. The expected measurement uncertainty is respectively of 0.05% and of 0.04° for amplitude and phase of the measured impedance in the frequency range of 40 Hz to 10 kHz.

    Parvis M.; Vallan A. – Neural Network in the Medical FieldAims of this book are to disseminate wider and in-depth theoretical and practical knowledge about neural networks in measurement, instrumentation and the related industrial applications. It also creates a clear consciousness about the effectiveness of these techniques as well as the measurement and instrumentation application problems in industrial environments. Finally, it wants to promote the practical use of these techniques in the industry

    Bertocco M.; Cappellazzo S.; Carullo A.; Parvis M.; Vallan A. – Virtual environment for fast development of distributed measurement applicationsThis paper deals with a virtual environment that allows automatic measurement systems to be easily developed by accessing programmable instrumentation, which can be located either in a local or in a remote laboratory. The environment, which is based on a client-server application that runs on a single personal computer or over the Internet, is designed to hide most of the details connected to the setup of a complex measurement system to the users. Client and server applications have been developed in Java™ language so that they can be used on different platforms and are easily extensible to accommodate new processing tasks, interfaces, and instruments

    Bertocco M.; Cappellazzo S; Narduzzi C; Parvis M. – An advanced distributed architecture for telemonitoring servicesThis paper presents the results of the European Community research project ADA, Advanced Distributed Architecture for Telemonitoring Services. The project main purpose is to provide a framework for the development of a distributed sensor network. Main elements of the system architecture are identified and their functions are discussed. An outline of a possible implementation based on the Jini™technology is provided.

    Carullo A.; Parvis M.; Vallan A. – An audio card-based kit for educational purposesThis paper describes an inexpensive kit which is designed to allow users to get acquainted with modern instrumentation without the necessity to get to a laboratory where the instruments are available. The kit takes advantage of any low-cost audio card installed into a personal computer and is based on an open-source code, which interacts with the audio card, and on a simple test board, which allows the audio card to be calibrated. The kit is the base of the Instrumentation Training Project at the Politecnico di Torino, which is composed of a set of guided experiments based on the capabilities of the training kit

    Parvis M.; Perrone G; Vallan A – A precompliance EMC test-set based on a sampling oscilloscopeIn this paper, a precompliance test-set for the measurement of conducted emissions based on a medium-level sampling oscilloscope and on a fast filtering algorithm (DFT) is presented. This system has been designed as a low-cost alternative to the typical precompliance test-sets that are based on spectrum analyzers equipped with EMC filters and peak detectors. Experimental examples of the results obtained using a sampling oscilloscope with 8 Kbytes of memory are given

    Carullo A; Parvis M; Vallan A.; Callegaro L – Automatic compensation system for impedance measurementThis paper deals with the realization of the four-pair terminal definition of impedance standards. A simple thought reliable system is described that allows an automatic compensation of the voltage at the low potential port of impedance standards to be obtained. Such a system, which employs a commercial DAQ board and an arbitrary signal generator, is controlled through a standard PC that implements the demodulation and the control algorithms. Preliminary tests have been performed in the frequency range of 50 Hz to 20 kHz with different kinds of impedance standards (resistive, inductive and capacitive), obtaining a residual voltage at the low potential port of less than 5 μV

    Parvis M.; Vallan A. – Medical measurements and uncertaintiesMeasurements in the medical field are peculiar in at least two ways: they deal with a terribly complex object-the patient-and are performed and managed by another terribly complex instrument-the physician. However, they are measurements and, like all measurements, they have their own uncertainty, which can affect any decision regarding the invaluable - object to be measured-the patient. This article, without any claim to be exhaustive, discusses how the uncertainty of a complex clinical measurement can be estimated, how the physician-based instrument affects it, and how it can affect the final diagnosis

    Carullo A.; Parvis M.; Vallan A. – Security Issues for Internet-Based Calibration ActivitiesThis paper describes a software tool that is able to remotely exercise the calibration procedure of a measurement device. Such a tool, which is based on a client-server application over the Internet, requires that the Unit Under Test (UUT) and the reference standard are programmable instruments that are connected to the PC where the client application runs. This allows the calibration of the UUT to be performed without move it, thus drastically reducing the out-of-service time. Furthermore, the presence of a skilled technician is not required at the UUT site, so that the overall calibration cost is reduced. Particular attention is payed towards the 'security' problems related to the exchange of information over the Internet and a solution is proposed in order to give an high confidence in data integrity and system inaccessibility. In the paper, the authors describe a specific application of the calibration software, which has been specialized for the remote calibration of data acquisition boards. A travelling standard, which has been specifically designed for this application, is also described.

    Carullo A; Parvis M; Vallan A. – An audio-card based kit for educational purposesThis paper describes an inexpensive kit which is designed to allow users to get acquainted with modern instrumentation without the necessity to get to a laboratory where the instruments are available. The kit takes advantage of any low-cost audio board installed into a personal computer and is based on an open-source code, which interacts with the audio board, and on a simple test board, which allows the audio board to be calibrated. The kit is the base of an Instrumentation Training Project, which is composed of a set of guided experiments based on the capabilities of the training kit.

    Parvis M.; Bertocco M.; Cappellazzo S.; Narduzzi C. – A distributed sensor network based on Jini(TM) technologyhis paper presents a framework for the development of a distributed sensor network which has been designed to fulfill the requirements of the European Union project on Advanced Distributed Architecture for Telemonitoring Services (ADA). The proposed architecture relies on the Jini™ functionality and implements a plug & play feature so that new sensors are readily made available to the users.

    Parvis M.; Bertocco M.; Cappellazzo S.; Flammini A. – A multi-layer architecture for distributed data acquisitionThis paper describes an architecture for distributed control of a sensors network through Internet. The architecture is based on a multiple layer structure that allows scalability when a large number of sensors is planned. Accounting and access policies are also addressed. Since standard web interfaces are adopted, the architecture allows an easy integration with already available products to be obtained. A practical case-study is also presented where sites in different cities cooperate for data retrieval from different sensors

    Parvis M; Perrone G; Vallan A. – A precompliance EMC test-set based on a sampling oscilloscopeA low-cost EMC precompliance test-set is essential to reduce the development costs of any electrical device. In this paper a precompliance test-set which is based on a general purpose sampling oscilloscope and on a fast filtering algorithm is presented. This system has been designed as a low-cost alternative to the typical precompliance test-sets for the measurement of conducted emissions that are based on spectrum analyzers equipped with EMC filters and peak detectors. An experimental example of the results obtained with a sampling oscilloscope equipped with 8 kbyte of memory is given.

    Carullo A; Parvis M; Vallan A. – Measurement of spurious-related errors on commercial wattmetersA procedure for the estimation of digital-wattmeter sensitivity with respect to the presence of spurious components in the acquired signals is proposed in this paper. The procedure allows an analytical estimation of such a sensitivity to be obtained if the spectral-analysis algorithm of the wattmeter under investigation is completely known; otherwise, an experimental estimation is required. Two different procedures are proposed: one approach can be used if the wattmeter is based on an FFT algorithm, while another longer procedure is able to characterize any kind of wattmeters. Both experimental procedures can be performed by employing a simple test-set, which is based on two commercial signal generators and on a Personal Computer.

    Parvis M.; Gulotta C; Torchio R. – Mixed Neural-Conventional Processing to Differentiate Airway Diseases by Means of Functional Noninvasive TestsThis paper describes a processing technique that can be used to combine information from different medical analyze to discriminate between different pathologies that have similar symptoms. The paper is focused on the differentiation between asthma, bronchitis, and emphysema, using only functional noninvasives tests, but the proposed technique can be easily applied to other similar situations where different tests have to be used to identify a pathology. The technique is based on mixed neural-and-conventional processing that not only suggests the pathology, but also estimates the reliability of this suggestion

    Parvis M.; Gulotta C.; Torchio R. – Portable system for fast lung function testThe analysis of gas-concentration changes at mouth during normal breathing is nowadays a routine exam to infer the lung functionality and several commercial instruments are available to carry out this kind of measurements. Unfortunately, most of these measuring systems are very specific, designed to be used in the hospital and costly. This paper describes a complete and versatile system which is designed for in the field use and can be tailored to several different measurement situations. The proposed system employs commercial sensors coupled to a versatile conditioning and acquisition board, which is designed to be connected to a conventional Personal Computer. A skeleton of a software which carries out the routine tasks (acquisition, storing, calibrations, and visualization) has been designed and installed on the PC. The skeleton can be easily adapted to the different applications, thus enabling the fast development of new clinical methodics. As an example, in this paper, an application is described that performs an Oxygen/Carbon-Dioxide analysis on a multi-breath basis and estimates the result uncertainty. The skeleton contains routines to save both results and raw data according to the Digital Imaging and Communication in Medicine (DICOM) standard format, so that the analyzes can be easily shared among the different physicians involved in the patient's care.

    A. Carullo; Ferraris F.; M. Parvis; A. Vallan – Sistema di misurazione di impedenza basato su algoritmo di sine-fit

    A. Carullo; Ferraris F.; M. Parvis; A. Vallan – Taratura in situ di schede di acquisizione dati: un nuovo approccio basato su un campione viaggiante controllato a distanza

    Carullo A.; Parvis M. – An Ultrasonic Sensor for Distance Measurement in Automotive ApplicationsThis paper describes an ultrasonic sensor that is able to measure the distance from the ground of selected points of a motor vehicle. The sensor is based on the measurement of the time of flight of an ultrasonic pulse, which is reflected by the ground. A constrained optimization technique is employed to obtain reflected pulses that are easily detectable by means of a threshold comparator. Such a technique, which takes the frequency response of the ultrasonic transducers into account, allows a sub-wavelength detection to be obtained. Experimental tests, performed with a 40 kHz piezoelectric-transducer based sensor, showed a standard uncertainty of 1 mm at rest or at low speeds; the sensor still works at speeds of up to 30 m/s, although at higher uncertainty. The sensor is composed of only low cost components, thus being apt for first car equipment in many cases, and is able to self-adapt to different conditions in order to give the best results

    Parvis M.; Gulotta C.; Torchio R. – Uncertainty Analysis of Feature Extraction from Expired Gas TracesNoninvasive medical analyses are a convenient method to study several pathologies even though their indirect nature often requires a complex processing to determine the relevant health "indicators". The usefulness of such indicators depends on the employed model, but also on the uncertainty that is connected to the complex processing involved in the indicator determination. This paper deals with the problems related to the estimation of the uncertainty when the indicators are computed by means of a nontrivial processing on recorded traces of clinical parameters. The paper is focused on the analysis of expired gas traces, but the procedure can also be applied to many other cases where the processing involves manual or automatic selection of suitable "key points" on repetitive traces

    Bertocco M; Cappellazzo S; Carullo A; Parvis M; Vallan A. – Virtual environment for fast development of distributed measurement applicationsThis paper describes a virtual environment that allows efficient development of distributed measurement applications. Most of the details associated with the set up of complex measurement systems are hidden to the programmers, so that most programmable instrument can be easily integrated and managed. The environment is based on the Java language so that it can be used on different platforms and is easily extensible to accommodate new processing tasks, interfaces and instruments

    Carullo A; Parvis M; Vallan A. – A travelling standard for the calibration of data-acquisition boardsThe large use of measurement systems based on data-acquisition boards makes the traceability-chain assurance a tricky problem, due to the difficulty in consistency calibrating such boards. In this paper the authors describe a travelling standard, which can be used for the calibration of many commercially available acquisition boards. By employing such as travelling standard, the calibration procedure can be remotely exercised by a calibration laboratory through the PC which hosts the board that has to be calibrated. In such a way the calibration results refer to environmental, software and hardware conditions that exactly match the board operating-conditions. Furthermore, the board unavailability time is drastically reduced, with a consequent economic advantage for the board owner. The travelling standard embeds a micro-controller, which is responsible for the communication with the PC that hosts the board and for the board-stimulus generation, and a digital multimeter, which acts as a reference standard.

    Carullo A.; Parvis M.; Vallan A. – Fast impedance analyser for corrosion monitoringFrequency Response Analysers (FRA) are commonly employed to monitor the corrosion state of metallic antiquities. Commercial devices, though very accurate and versatile, are often rather costly and require a long time to complete the Electrochemical Impedance Spectroscopy (EIS). This paper describes a low cost and portable alternative to commercial FRAs that also embeds the potentiostatic function and therefore can be used in the field without requiring external devices. The proposed instrument is based on a compact DSP board and employs a sine-fit algorithm for the impedance measurement; the paper also describes a fast algorithm to obtain the results without requiring long measuring sessions. The proposed instrument automatically performs a simple coating test and is equipped with a digital interface so that it can be connected to a personal computer to carry out a complete frequency analysis and to perform more complex data processing

    A. Carullo; F. Ferraris; M. Parvis; Vallan A.; E. Angelini; P. Spinelli – Low-cost electrochemical impedance spectroscopy system for corrosion monitoring of metallic antiquities and works of artElectrochemical impedance spectroscopy (EIS) is recognized to be a powerful and noninvasive technique to test the integrity of protective coatings on memorials, but commercial EIS systems are rather costly though versatile devices. This paper describes a low cost and portable EIS system that is based on a compact digital signal processor (DSP) board and embeds the potentiostatic function so that it can be used without requiring an external potentiostat. The software that runs on the DSP is designed to analyze the electrochemical impedance only in a reduced frequency range in order to produce a simple corrosion alert result. The device is equipped with a digital interface and can be connected to a personal computer to carry out a complete frequency analysis and perform a more complex data processing

    Carullo A.; Parvis M.; Vallan A. – Mass measurement into a freeze-dryerThis paper deals with two scales that are conceived to operate inside a freeze-dryer, where the environmental conditions (temperature down to - 80 ºC and pressure down to 0.5 Pa) prevent traditional mass transducers to be employed. One scale is based on a parallel-electrode capacitor, whose capacity depends on the position of a moving electrode that, in turn, depends on the unknown mass. The capacity change is converted into a frequency change by means of an oscillator circuit. The second scale, which is still under development, is based on electrostatic levitation. A fixed metallic plate is divided into four sectors connected to a high voltage generator. The resulting electric field is used to levitate a moving metallic plate which carries the unknown mass. A prototype of the capacitor-based scale has shown an uncertainty of a few tenths of grams in the range of 0 g to 250 g

    Parvis M.; Bertocco M. – Platform independent architecture for distributed measurement systemsThis paper describes a software architecture that can be employed to exercise a distributed measurement system. The proposed architecture allows many users to simultaneously access instruments physically located in different sites, to program them and to gather the measurement results. The multi-user capability is obtained by means of an intelligent queuing process, while the multi-instrument access is accomplished by means of a self-synchronizing architecture. The developed software is platform independent both on instrument and user sides thanks to the use of an Http-based protocol and of Java components. The proposed system embeds robust security mechanisms with user identification and encrypted transactions.

    Parvis M.; Gulotta C.; Torchio R – Uncertainty analysis of feature extraction from expired gas tracesNon invasive medical analyses are a convenient method to study several pathologies and determine important health `indicators', even though an estimation of the indicator uncertainty is often difficult to obtain. The usefulness of such indicators depends on the employed model, but also on the uncertainty that is connected with the indicator determination. This paper deals with the problems related to the estimation of the uncertainty when the indicators are computed by means of a non trivial processing on recorded traces of clinical parameters. The paper is focused on the analysis of expired gas traces, but the procedure can be applied in many other cases where the processing involves the manual or automatic selection on suitable `key points' on repetitive traces.

    Parvis M.; Vallan A. – Uncertainty contribution in power measurements due to non-harmonic componentsDigital-wattmeter uncertainty specifications are typically provided for sinusoidal signals only. In some cases specifications are provided also in the presence of harmonic components, but the presence of spurious non-harmonic components is never taken into account. This paper describes a simple algorithm, which is able to estimate the uncertainty increase that is related to such components.

    Benettazzo L; Bertocco M; Ferraris F.; Ferrero A; Offelli C; Parvis M; Piuri V – A Web-Based Distributed Virtual Educational LaboratoryEvolution and cost of measurement equipment, continuous training, and distance learning make it difficult to provide a complete set of updated workbenches to every student. For a preliminary familiarization and experimentation with instrumentation and measurement procedures, the use of virtual equipment is often considered more than sufficient from the didactic point of view, while the hands-on approach with real instrumentation and measurement systems still remains necessary to complete and refine the student's practical expertise. Creation and distribution of workbenches in networked computer laboratories therefore becomes attractive and convenient. This paper describes specification and design of a geographically distributed system based on commercially standard components

    Carullo A; Ferraris F; Parvis M; Vallan A.; Angelini E; Spinelli P – Low-cost electrochemical impedance spectroscopy system for corrosion monitoring of metallic antiquities and works of artElectrochemical impedance spectroscopy (EIS) is recognized to be a powerful and noninvasive technique to test the integrity of protective coatings on memorials, but commercial EIS systems are rather costly though versatile devices. This paper describes a low cost and portable EIS system that is based on a compact digital signal processor (DSP) board and embeds the potentiostatic function so that it can be used without requiring an external potentiostat. The software that runs on the DSP is designed to analyze the electrochemical impedance only in a reduced frequency range in order to produce a simple corrosion alert result. The device is equipped with a digital interface and can be connected to a personal computer to carry out a complete frequency analysis and perform a more complex data processing

    Parvis M.; Pirola M. – A Measurement System for On-line Estimation of Weed CoverageThis paper describes two different solutions for the estimation of weed coverage. Both measuring systems discriminate the weed from the ground by means of the color difference between the weed and ground and can be used to on-line control tractor sprayers in order to reduce weedkiller use. The solutions differ with respect to the sensor type: one solution is based on a digital camera and a computer that analyzes the images and determines the weed amount, while the other simpler solution makes use of two photo detectors and an analog processing system. The camera-based solution provides an uncertainty of a few percentage, while the photo detector-based one, though extremely cheap, has an uncertainty of about 5% and suffers from changes in light conditions, which can alter the estimations

    Carullo A.; Ferrero A.; Parvis M. – A Microwave System for Relative Humidity MeasurementThis paper deals with a microwave hygrometer that is based on the sensitivity of air permettivity to humidity. The hygrometer embeds a microwave generator which feeds two different channels. A channel is a holed waveguide, whose permettivity depends on the air humidity, while the other channel is insensitive to the air humidity. The output signals of the two channels are suitably combined in order to obtain the corresponding phase angle, which depends on the permettivity of the air inside the holed waveguide and therefore on the air humidity. Two possible implementations of the proposed principle are described which permit one to obtain an uncertainty of a few percentage of relative humidity in the humidity range of 10% RH to 90% RH and in the temperature range of 5 °C to 40 °C, but with different costs and complexities. The main characteristics of the proposed sensor are a fast response, a low sensitivity with respect to air pollution and the absence of hysteresis phenomena

    Parvis M, Gulotta C, Tochio R – Mixed neural-conventional processing to differentiate airway diseases by means of functional non-invasive testsThis paper describes a processing technique that can be used to combine the pieces of information coming from different medical analyses. Such a technique is based on a mixed neural-and-conventional processing that allows both an easy neural network training and a robust estimation to be obtained. The paper is focused on the differentiation of asthma, bronchitis and emphysema by using functional non-invasive tests only, but the proposed technique can be easily applied to several different situations

    Benetazzo L; Bertocco M; Ferraris F; Ferrero A; Offelli C; Parvis M; Piuri Vi – A Web-based distributed virtual educational laboratoryEvolution and cost of measurement equipment, continuous training, and distance learning make difficult to provide a complete set of updated workbenches to every student. For a preliminary familiarization and experimentation with instrumentation and measurement procedures the use of virtual equipment is often considered more than sufficient from the didactic point of view. Creation and distribution of workbenches in networked computer laboratories becomes therefore attractive and convenient. This paper describes specification and design of a geographically distributed system based on commercially standard components

    Parvis M.; Bertocco M. – An auto-routing multi-server architecture for high-education training on instrumentation and measurementThis paper describes a set-up that can be employed for high-education training on instrumentation and data acquisition systems. The proposed solution allows many users to simultaneously access groups of real instruments to program them and to gather the measurement results. The multi-user, multi-instruments sessions are obtained by means of a queuing process with instrument locking capability. The architecture is based on a domain of instrument servers which is capable of automatically route the requests of any client toward the faster available server that is capable of satisfying the client request. Client applications can be easily developed by using conventional high-level programming languages, well-assessed virtual instrumentation frameworks or by using a standard Internet browser as front end

    Vallan A., Carullo A., Ferraris F., Parvis M. – An automatic calibrator for wattmeters with harmonic analysis capabilityThis paper deals with a three-phase phantom-power generator, which is designed for calibrating digital wattmeters with harmonic analysis capability. The calibration of such instruments is a critical task due to the lack of suitable calibrators. Fortunately, the calibration procedure can be limited to the first harmonic components when digital wattmeters are employed to characterise electrical machines, so that also simple calibrator design can be adopted. This paper describes a three-phase calibrator arrangement which is able to generate an arbitrary spectrum up to 5 kHz and a phantom power variable up to 3 kVA per phase. The uncertainty on the power associated to the first harmonic components is of about 0.1 % in nonsinusoidal conditions. The calibrator employs a Direct Digital Synthesis technique, so that a frequency change of the output signal can be obtained without modifying the sampling frequency. Such a technique also permits to generate the frequency modulated signals that are often encountered at the output of static power converters that feed electrical machines

    Bertocco M.; Ferraris F.; Offelli C.; Parvis M. – A Client-Server Architecture for Distributed Measurement SystemsThis paper describes a client-server architecture for the remote control of instrumentation over the Internet network. The proposed solution allows multiuser, multi-instrument sessions by means of a queueing and instrument locking capability. Client applications can be easily developed by using conventional high-level programming languages or well-assessed virtual instrumentation frameworks. Performance tests are reported; they show the low overhead due to network operation with respect to the direct control of instrumentation

    Parvis M.; Gulotta C.; Torchio R. – Evaluation of surgical risks by means of neural networks in the presence of uncertaintiesSurgical risks in elderly patients are often rather high and therefore a need exists for preoperative tests that are able to predict the postoperative risk of mortality. In most cases no test has been found to be completely able to predict postoperative severe complications although reasonable results can be obtained by employing a multi-test approach. A neural network can conveniently be employed to perform the required data-fusion thus producing an overall "risk index"; however the surgical outcome being of a binary type, the network output tends to be a step-like function that does not give much information on the risk level. In this paper a modified training approach that takes the parameter uncertainties into account and which trains the network avoiding the step-like behaviour is proposed. The results that can be obtained with this approach are eventually explained by applying it to the estimation of a surgical risk index for lung resection procedures in patients affected by lung cancer

    Carullo A.; Ferraris F.; Parvis M.; Vallan A. – Phantom power generator for the calibration of wattmeters in distorted environments

    Boglietti A.; M. Pastorelli; A. Carullo; M. Parvis – Testing of inverter fed electrical machines: Instrumentation and procedure problems

    A. Carullo; M. Parvis; Vallan A. – An analytical balance for lyophilisation systemsThe description of industrial lyophilization processes by means of theoretical models requires a balance that is suitable for the very severe environmental conditions that take place in a freeze-dryer. A capacitive analytical balance that is able to operate in the temperature range of -80 °C to +20 °C and in the pressure range of 0.5 Pa to 100 kPa is described in this paper. Such a balance is based on a parallel-electrode capacitor whose capacity is affected by the mass of the substance that is placed on the moving electrode of the capacitor. The capacitor acts as the reactive element of a oscillator circuit that converts the capacity into frequency. Such a frequency is measured and eventually converted in a mass measurement. The prototype the authors have made has a range of about 300 g, is 6 cm high and has a diameter of about 18 cm. The operating principle of the balance is described and the results obtained during different lyophilization processes are shown

    Bertocco M, Ferraris F, Offelli C, Parvis M – A client-server architecture for distributed measurement systemsThis paper describes a client-server architecture for the remote control of instrumentation over the Internet network. The proposed solution allows multi-user, multi-instruments sessions to be obtained by means of a queuing process and provides instrument locking capability. Client applications can be easily developed by using conventional high-level programming languages or well-assessed virtual instrumentation frameworks. Performance tests are reported, which show the low overhead due to network operations with respect to the direct control of the instruments

    Parvis M; Pirola M. – A measurement system for on-line estimation of weed coverageThis paper describes two different solutions for the estimation of weed coverage. Both measuring systems discriminate the weed from the ground by means of the colour difference between the weed and ground and can be used to on-line control tractor sprayers in order to reduce weedkiller use. The solutions differ with respect to the sensor type: one solution is based on a digital camera and a computer that analyses the images and determines the weed amount, while the other simpler solution makes use of two photo detectors and an analogue processing system. The camera-based solution provides an uncertainty of a few percent, while the photo detector-based one, though extremely cheap, has an uncertainty of about 5% and suffers from changes in light conditions, which can alter the estimations

    Carullo A.; Ferrero A.; Parvis M. – A microwave environmental humidity sensor

    Parvis M.; Carullo A; Ferrero A – A microwave interferometer system for humidity measurementA microwave interferometer system for humidity measurement has been developed. The system is based on the sensitivity of the air permittivity to the water vapor content and offers a faster response and a better air pollution insensitivity with respect to the traditional humidity sensors which are based on hygroscopic substances. Experimental results show the effectiveness of the new approach in the range of 20%RH to 70%RH

    A. Carullo; A. Ferrero; M. Parvis – A microwave interferometer system for humidity measurementA microwave interferometer system for humidity measurement has been developed. The system is based on the sensitivity of the air permittivity to the water vapor content and offers a faster response and a better air pollution insensitivity with respect to the traditional humidity sensors which are based on hygroscopic substances. Experimental results show the effectiveness of the new approach in the range of 20% RH to 70% RH

    Carullo A.; Parvis M.; Boglietti A.; Pastorelli M. – Instrumentation and measurement problems in inverter-fed electrical machines

    Carullo A.; Parvis M.; Vallan A. – Low-cost power meter for the characterisation of inverter-fed electrical machinesThis paper describes a versatile though low cost power meter that was specifically conceived for the characterization of inverter-fed electrical machines. The power meter has been designed to perform a measurement of the electrical quantities associated to the first harmonics that are obtained with an uncertainty of less than 0.1%. The power meter is simple and cheap thanks to the restriction of the measurement capabilities to the first harmonics, which allows low cost converters to be used. The wattmeter employs a Digital Signal Processor to obtain a measuring rate in excess of 2 Hz; a conventional Personal Computer is used for the graphical interface. The power meter characterization is obtained by means of a special designed generator that allows distorted though known waveforms to be generated

    Carullo A; Parvis M. – Power meter for Highly-Distorted Three-Phase SystemsThis paper describes a low-cost, three-phase power meter, which is based on a fast, specially designed acquisition board coupled to a PC via the PC parallel/printer port or by means of an AT card. The power associated with the fundamental and first harmonics is computed by software that operates in the time domain and employs a sample-weighting procedure that makes the uncertainty related to the asynchronous sampling negligible. The low-cost acquisition board features two 8-bit 1 MHz converters and a local RAM, which decouples the PC clock from the measurement requirements. Hall effect transducers are used for the current channels and fast differential amplifiers for the voltage channels. The fast sampling frequency allows simple antialiasing filters to be employed. Digital filtering is used to reduce the sample number while increasing the resolution. The power uncertainty provided by this arrangement is less then 0.1 % with 2.5 measurements per second when a low-cost 486DX33-based PC is used

    Bertocco M.; Ferraris F.; Offelli C.; Parvis M. – Training of programmable instrumentation: a student laboratory

    A. Carullo; M. Parvis; Vallan A. – Water content measurement in granular materials using ultrasonic wavesThe measurement of the water content of granular materials is an important task in agriculture as well as in the food industry. No available measuring method provides completely satisfactory results either because of the lengthy measurement operations or due to the maintenance of accuracy problems. This paper discusses the possibility of determining the water potential, from which the water content can eventually be determined, by using ultrasonic waves. The discussed solution employs the ultrasonic waves to determine the velocity of sound in a chamber inserted into the material and a solid state sensor to determine the temperature. The knowledge of these parameters allows one to compute the relative humidity from which the water potential is readily obtained. Experimental results are reported that refer to tests carried out in a soil sample under controlled conditions and that confirms the feasibility of the solution

    Carullo A.; Ferraris F.; Grimaldi U.; Parvis M. – Il sensore intelligente

    Carullo A, Parvis M – Power meter for highly-distorted three-phase systemsThis paper describes a low-cost three-phase power meter, which is based on a fast special-designed acquisition board coupled to a personal computer. Such a solution permits an easy design of the acquisition board and the arrangement of a compact and portable instrument. In addition, the software updating is extremely easy and the availability of a powerful graphic interface makes the instrument use rather friendly. The acquisition board is based on low cost 8 bit analogue to digital converters. The converters have a maximum sampling rate of 1 MHz and store the results in a static 512 Kbyte local RAM, which decouples the personal computer speed from the measurement necessities. Hall-effect transducers are used for the current channels and fast differential amplifiers for the voltage channels. Both Aron and complete three-phase system configurations are available. The board connection to the computer is obtained either by means of a special designed AT card or the widely diffused parallel/printer port. This last possibility makes it possible to perform in-field measurements using small subnotebook computers

    Carullo A.; Ferraris F.; Graziani S.; Grimaldi U.; Parvis M. – Ultrasonic distance sensor improvement using a two-level neural networkThis paper discusses the performance improvement that a neural network can provide to a contactless distance sensor based on the measurement of the time of flight (TOF) of an ultrasonic (US) pulse. The sensor, which embeds a correction system for the temperature effect, achieves a distance uncertainty (rms) of less than 0.5 mm over 0.5 m by using a two-level neural network to process the US echo and determine the TOF in the presence of environmental acoustic noise. The network embeds a "guard" neuron that guards against gross measurement errors, which would be possible in the presence of high environmental noise

    Parvis M.; Carullo A; Ferraris F – A low-cost contactless distance meter for automotive applicationsThis paper describes an ultrasonic sensor that is able to measure the distance from the ground from selected points of a motor vehicle. The sensor is based on the measurement of the time of flight of an ultrasonic pulse, which is reflected by the ground. An uncertainty of 1 mm (1 σ) is obtained at rest or at low speeds; the sensor still works at speeds of up to 30 m/s although at reduced accuracy. Such a performance is obtained by employing a series of optimisation that allow the sensor to self-adapt to the different conditions to give the bests results. The sensor is composed of only low cost components, thus being apt for first car equipment in many cases

    Grimaldi U.; Parvis M. – Enhancing the ultrasonic sensor performance by the optimisation of the driving signalThe issue arising from limitations in sensor performance is crucial in most measuring systems, so it is a matter of high interest to define strategies able to optimize a sensor's behaviour. This paper describes a method for determining a sensor driving signal that enhances the sensor capabilities in stimulation-and-response-based measuring systems. The method is based on a signal theory approach and is quite general, enabling the best performance for different kinds of sensors to be obtained, provided that they can be described in terms of transgfer functiions and that the required performance can be represented by suitable functionals. The method's capabilities are shown in an application involving the measurement of the time-of-flight of ultrasonic pulses. A resolution improvement of more than one order of magnitude is achieved with respect to the standard approaches, still employing low-cost low-damping devices

    Grimaldi U.; Parvis M. – Noise-tolerant ultrasonic distance sensor based on a multiple driving approachUltrasonic sensors are a cost-effective solution to the problem of distance measurement when contactless operation is required. They are robust, intrinsically safe, and capable of noticeable accuracy when used in quiet environments, but suffer from acoustic noise that can greatly reduce their performance. In this paper an ultrasonic distance sensor that is able to provide good performance in different conditions is presented. The good performance is obtained by automatically changing the signal that drives the transmitter according to the environmental noise level. Such an approach allows accuracies of up to 1 mm to be obtained in distance measurements up to a few meters, even in the presence of acoustic noise levels which would otherwise impair the sensor performance. The proposed sensor is cheap and easy to be implemented, therefore enabling the design of low-cost, high-performance devices

    Ferraris F.; Grimaldi U.; Parvis M. – Procedure for effortless in-field calibration of three-axial rate gyro and accelerometersThe contemporaneous use of three-axis rate gyro and accelerometer is required in industrial applications such as strap-down platforms. The use of low-cost sesnors ofter requires a calibration immediately before the sensor use. This paper describes a procedure which does not require either angular velocity standards or standard accelerometers. The procedure makes use of the local gravity and of a set of rotations returning to the original position

    Carullo A, Ferraris F, Graziani S, Grimaldi U, Parvis M – Ultrasonic distance sensor improvement using a two-level neural networkThis paper discusses the performance improvement that a neural network can provide to a contactless distance sensor based on the measurement of the time of flight (TOF) of a ultrasonic (US) pulse. The sensor, which embeds a correction system for the temperature effect, achieves a distance accuracy (rms) better than 0.5 mm over 0.5 m by using a two-level neural network that processes the US echo in order to correctly determine the TOF in the presence of environmental acoustic noise

    Parvis M. – Using a-priori information to enhance measurement accuracyThe term "a-priori information" means a piece of information about the investigated reality that is not obtained by the measuring instruments that carry out the measurement, but is known from other sources. A-priori information is commonly used in the design phase of a measurement procedure, but in several cases it is possible to use this "external" information in a direct and more powerful way to validate measurement results or even to correct the results themselves, obtaining in this way a better accuracy. In this article an algorithm is presented which is useful for integrating any available a-priori information within a measurement process to obtain a better accuracy. A method to estimate the uncertainty of the results after the proposed corrections, and some clarifying examples are also presented

    Carullo A.; Ferraris F.; Parvis M. – A fast-response low-cost ultrasonic humidity sensor

    Ferraris F.; Gorini I.; Grimaldi U.; Parvis M. – Calibration of three-axial rate gyros without angular velocity standardsGyro calibration is a complex taskm, mainly because of the difficulty of managing angular velocity standards. This is especially true 'in field' and therefore low-cost sensors cannot to be used in high-accuracy applications. This paper presents a calibration process that does not require rotating tables or other velocity standards. The calibration is carried out making reference only to geometrical quantities and using the A/D conversion system and the computing system normally connected to the gyro. The calibration can be completed in a few minutes, and results in a noticeable improvement in accuracy

    Parvis M.; Ferraris: F; Grimaldi U; Graziani S – A neural network for fast-response ultrasonic distance sensorsUltrasonic techniques can provide a cost effective solution for distance measurements, but frequently suffer from poor resolution and acoustic noise. In this paper a new approach based on neural networks to process the echo signal is described, it permits the improvement of the resolution of the distance measuring systems by employing ultrasonic techniques and requires a negligible computing time, even though the network, is implemented without special purpose hardware. The results obtained with less-than-one-dollar piezoelectric transducers and a neural network are described. The neural network performance is compared with that of traditional techniques. A sub-millimeter resolution is obtained even in the presence of some acoustic noise, which could prevent other simple detection strategies

    Parvis M. – Measurement of residence time distribution function by means of a non invasive magnetic sensorIndustrial measurement techniques are often required to work on complex plants where it is important to obtain data on the processes without affecting them. This may impose the development of specific sensors and the use of sophisticated signal processing techniques in order to obtain the required information. The article describes the development and the characterisation of a measurement technique for obtaining the Residence Time Distribution Function of a reactor for post-poli-condensation of Poly-Ethylen-Terephtalate pellets. The adopted measurement technique is based on marking the reacting material by means of iron powder and uses a non-invasive magnetic sensor. Both the development and the characterisation have been carried out using a 'measurement development system' which allows the initial work to be significantly reduced. Although the description is focused on a specific problem, the proposed processing techniques may be used for various problems involving measurements related to the flow of plastic pellets. Finally, a simple complete measurement system, based on the proposed technique, is described

    Parvis M. – A magnetic sensor for measuring plastic pellet flowThe measurement of the flow of a granular material is an important task in several engineering fields. The ability to carry out such measurement in adverse conditions is also required, especially in industrial environments, when it is necessary to work on complex plants and it is important to obtain data about the process without affecting it. This may impose the development of specific sensors and the use of sophisticated signal processing techniques to obtain the required information. This article deals with the design, development, building and characterisation of a magnetic sensor useful for estimating the material flow of granular plastic pellets, based on magnetic marking of the reacting material and analysing the signal obtained by a detection coil while the pellets pass through a suitable magnetic field

    Parvis M. – Strumento intelligente per la misurazione di grandezze elettriche

    Greco-Lucchina P.; Gulotta C.; Parvis M.; Pozzi R.; Torchio R.; Tosadori A. – Effetti della nifedipina sulla circolazione polmonare determinati con metodica non invasiva, in volontari sani

    Ferraris F.; Gorini I.; Parvis M. – Intelligent multi-input instrument for electrical measurementsThe main characteristics of an intelligent measuring instrument for electrical quantities are outlined, putting in evidence the role of intelligence. Particular emphasis is given to the functional viewpoint, describing the most important subsystems into which the whole equipment can be divided. The main processes performed, such as autoranging, systematic errors correction, autocalibration, automatic estimation of uncertainties, autodiagnosis and instrument-to-user interfacing are also highlighted. The instrument has been completely designed and a good deal of hardware and software has been implemented

    Ferraris F.; Parvis M. – The autodiagnosis system of an intelligent measuring instrumentThe methodological aspects and the design of the automatic self-diagnosis (auto-diagnosis) system of a high-performance measuring instrument for electrical quantities are described. The auto-diagnosis system can recognise not only severe failures which require out-of-service instrument setting, but also slight failures simply affecting accuracy or not basic features; in the latter case, the instrument is set working in degraded conditions. The auto-diagnosis process is performed making reference to the instrument architecture, based on independent and interconnected functional units, and using an analysis technique, called 'extending ring', to detect failing subsystems. The auto-diagnosis system is divided into two main parts, conceived for separate aims: one is named 'off-line full test auto-diagnosis system' and performs, at power up or on user request, a full comprehensive test; the other, named 'on-line auto-diagnosis system', continuously monitors the instrument behaviour while operating normally to reveal failures or error conditions that can derate the whole performance

    Abete A.; Parvis M. – Prova convenzionale per le caratteristiche dei moduli a semiconduttori termoelettrici