S. Zampolli

INO - Istituto Nazionale di Ottica, Florens, Tuscany, Italy

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Publications (65)71.04 Total impact

  • C Cagliero · S Galli · M Galli · I Elmi · M Belluce · S Zampolli · B Sgorbini · P Rubiolo · C Bicchi
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    ABSTRACT: Within a project exploring the application of lab-on-chip GC to in-field analysis of the plant volatile fraction, this study evaluated the performance of a set of planar columns (also known as microchannels, MEMS columns, or microfabricated columns) of different dimensions installed in a conventional GC unit. Circular double-spiral-shaped-channel planar columns with different square/rectangular sections up to 2m long were applied to the analysis of both essential oils and headspace samples of a group of medicinal and aromatic plants (chamomile, peppermint, sage, rosemary, lavender and bergamot) and of standard mixtures of related compounds; the results were compared to those obtained with reference narrow-bore columns (l:5m, dc:0.1mm, df:0.1μm). The above essential oils and headspaces were first analyzed quali-and quantitatively with planar columns statically coated with conventional stationary phases (5%-phenyl-polymethylsiloxane and auto-bondable nitroterephthalic-acid-modified polyethylene glycol), and then submitted to chiral recognition of their diagnostic markers, by enantioselective GC with a planar columns coated with a cyclodextrin derivative (30% 6(I-VII)-O-TBDMS-3(I-VII)-O-ethyl-2(I-VII)-O-ethyl-β-cyclodextrin in PS-086). Column characteristics and analysis conditions were first optimized to obtain suitable retention and efficiency for the samples investigated. The planar columns tested showed performances close to the reference conventional narrow-bore columns, with theoretical plate numbers per meter (N/m) ranging from 6100 to 7200 for those coated with the conventional stationary phases, and above 5600 for those with the chiral selector.
    No preview · Article · Jan 2016 · Journal of Chromatography A
  • Scorzoni A. · Tavernelli M. · Placidi P. · Zampolli S.
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    ABSTRACT: Wireless sensor networks (WSNs) are an important technology for large-scale monitoring, providing sensor measurements at high temporal and spatial resolution. In healthcare applications, a variety of system prototypes and commercial products have been designed and manufactured with the aim to provide an alternative and more efficient method for real time patient monitoring. In the framework of the Real time Active PIxel Dosimetry (RAPID) project, the attention has been focused on dose monitoring of Interventional Radiology operators. In this work, we present a study on the RF interface with the optimization of the antenna design to obtain a compact solution making the system portable. The effect of human body influence on the performance of the antenna has been simulated: a distance of 1.5 cm from the body shows that the artificial body structure has a negligible detuning effect on the antenna performances. The Packet Error Rate (PER) of the network has been evaluated considering different values of Transmitter Output Power (TPO) and comparing the performance of two different antennas: the maximum obtained PER was lower than 0.2%, which is acceptable for the specific application.
    No preview · Conference Paper · May 2015
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    ABSTRACT: This paper presents a comprehensive procedure for the design and implementation of thin film heaters manufactured on glass substrates. The thermal and electrical behavior of the heaters have first been simulated and proper design solutions have been adopted for increasing the thermal resistance of the heaters, thus decreasing their power consumption. Trenches were adopted in order to thermally isolate the heater from the glass substrate. The presence of four different layouts of trenches on the back and the front side of the glass slide with different geometries was extensively simulated. The simulated geometries were manufactured and an automatic sawing machine was exploited to dig 240 μm wide trenches in the glass substrate. The trenches were typically stopped at about 80 μm from the opposite surface. Techniques commonly adopted for measuring the temperature coefficient of resistance, the thermal resistance and thermal capacitance in the case of Si-based microheaters have conveniently been modified to take into account the fundamentally different thermal parameters of a heater manufactured on glass. An experimental improvement of the thermal resistance up to 217% on a heat sink and 30% in air has been obtained when a large part of the thermal mass under the microheater was removed. The thermal capacitance was also considerably decreased, thus improving the dynamic thermal behavior.
    No preview · Article · Mar 2015 · Sensors and Actuators A Physical
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    ABSTRACT: This paper presents an accurate thermal characterization of thin-film heaters manufactured on glass substrates. The characterization has been performed on Cr/Al/Cr meandered heaters. Techniques commonly adopted for measuring the temperature coefficient of resistance, the thermal resistance and thermal capacitance in the case of Si-based microheaters have been conveniently modified to consider the fundamentally different thermal parameters of a heater manufactured on glass. To reduce power consumption and thermal capacitance, a grating of 250-μm wide trenches, stopped at 80μm from the opposite metalized front surface, was manufactured on the back side of the heaters, obtaining an increase of the thermal resistance of about 110% and a decrease of the thermal capacitance of about 65% when the glass is in good thermal contact with a heat sink. The measured values of thermal resistance and time constants on a heat sink and in air have been justified starting from realistic physical considerations. Finally, a novel thermal model suitable for microheaters on glass immersed in air was presented and validated by comparing its predictions with the experimental cooling behavior of the microheater and with the predictions of an exponential model.
    No preview · Article · Nov 2014 · IEEE Transactions on Instrumentation and Measurement
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    ABSTRACT: Abstract— Border security is one of the key challenges to be taken up by Europe in the following years. In particular, the deployment of practical efficient means to detect hidden persons and illegal substances at border crossing points is instrumental in avoiding terrorism, human trafficking or smuggling. This study presents the concept of an “orthogonal” approach to the identification of gas traces identified as pertinent targets for illicit substances (drugs and explosives) as well as for human presence. The techniques employed to perform the analysis are based on completely different physical principles; these are the Mid-Infrared photo-acoustic spectroscopy (MIR-PAS - demonstration of a novel widely tunable integrated MIR source coupled with a miniature photo-acoustic cell) and the Ion mobility spectrometry (IMS) using a non radio-active ionization source. Definition of the pertinent compounds and their “spectral signature” (characterized with recording of the vapour phase IR properties via GC-FTIR and GC-MS), lead to a database of the target substances; the IR wavelengths were selected based on the individual target. For the case of human presence, volatile fatty acids (VFA) present in human sweat identified as ideal targets for remote detection of hidden persons; for example some VFAs are human specific, such as HMHA and 3MHA. The aforementioned VFAs are also active in the MIR range. Similarly for the case of the illicit drugs targeting has been based on their emitted VOCs depending on the type of substance (e.g. alkaloid drugs associated with their volatile degradation products etc); during this study, characterization of the cannabis markers lead to the identification of a new marker (under revision for European patent). For explosives substances volatile taggants are mainly associated with VOCs available during their preparation. In total 58 volatile organic compounds (VOCs) were identified in this study as candidates for the detection of Humans (31), Illegal Drugs (19), and Explosives (13). The aforementioned spectral database has been employed for algorithm selection and training; the algorithms used were the Support Vector Machines (SVM), Partial Least Squares – Discrimant Analysis (PLS – DA) and the k – Nearest Neighbour (KNN); the results are very promising reaching levels of matching during training up to 98%. These algorithms will fuse the data collected and analysed by the two powerful techniques selected as the components of this « orthogonal » approach to the detection of the aforementioned gas traces. Target specific cavitand receptors were developed for the pre-concentrator procedure that increase the concentration of the gas trace in quest. During this work, improvement to the pre-concentration configuration has reduced the required time for the pre-concentration procedure significantly (10s of seconds compared to several minutes); this is part of the novelties developed during this study. IMS studies for detection of human presence has shown very promising results, recording levels of human specific gas traces after 15 minutes of a human present in an area of 50m3. This is very important considering that in most cases the people illegaly immigrating are confined in much smaller spaces and for very much longer periods (most of the times are more than one person too) which leads to increased concentration and abundance of the related VOCs hence, the instrument will definetely perform better. A miniaturized MIR-PAS has been developed supported by an array of DFB-QCLs that allows for this instrument to be a portable solution for operators at border points, assisting their daily activities and increase their performance. This is a powerful and promising tool to detect a very wide range of volatile organic compounds (VOCs). Keywords—Border security, Orthogonal Technologies, IMS, MIRPAS, Human Detection, Illicit Drugs, Explosives, Olfactory, Mobile Instrument
    No preview · Conference Paper · Sep 2014
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    ABSTRACT: This paper describes a novel and easily manufacturable method for increasing the thermal resistance of microheaters fabricated on glass substrates, thus decreasing the thermal dissipation of the devices. An automatic sawing machine was exploited to dig 240 μm wide trenches in order to thermally isolate the heater from the glass substrate and four different layouts of the trenches have been investigated. An improvement of the thermal resistance up to 217% on a heat sink and 30% in air has been obtained. The thermal capacitance was also considerably decreased, thus improving the dynamic thermal behavior.
    Full-text · Conference Paper · Sep 2014

  • No preview · Conference Paper · Oct 2013
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    ABSTRACT: Analytical instruments based on InfraRed Absorption Spectroscopy (IRAS) and Gas Chromatography (GC) are today available only as bench-top instrumentation for forensic labs and bulk analysis. Within the 'DIRAC' project funded by the European Commission, we are developing an advanced portable sensor, that combines miniaturized GC as its key chemical separation tool, and IRAS in a Hollow Fiber (HF) as its key analytical tool, to detect and recognize illicit drugs and key precursors, as bulk and as traces. The HF-IRAS module essentially consists of a broadly tunable External Cavity (EC) Quantum Cascade Laser (QCL), thermo-electrically cooled MCT detectors, and an infrared hollow fiber at controlled temperature. The hollow fiber works as a miniaturized gas cell, that can be connected to the output of the GC column with minimal dead volumes. Indeed, the module has been coupled to GC columns of different internal diameter and stationary phase, and with a Vapour Phase Pre-concentrator (VPC) that selectively traps target chemicals from the air. The presentation will report the results of tests made with amphetamines and precursors, as pure substances, mixtures, and solutions. It will show that the sensor is capable of analyzing all the chemicals of interest, with limits of detection ranging from a few nanograms to about 100-200 ng. Furthermore, it is suitable to deal with vapours directly trapped from the headspace of a vessel, and with salts treated in a basic solution. When coupled to FAST GC columns, the module can analyze multi-components mixes in less than 5 minutes. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
    No preview · Conference Paper · Feb 2013
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    ABSTRACT: A portable, advanced IR sensor in a hollow fiber matched to a silicon micromachined fast gas chromatography column can analyze illegal stimulants and precursors with nanogram-level sensitivity.
    Full-text · Article · Jan 2013 · SPIENewsroom
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    ABSTRACT: In this paper a novel compact Spice model of a thermal conductivity detector (TCD) is presented and validated against an extensive experimental characterization and 3D simulations. The TCD used is based on the ultra low power (ULP) technology and it has been electrically characterized with different helium and nitrogen gas flow rates, via a microfluidic experimental setup. Extraction of global electro-thermal parameters, exploited for the development of the Spice model, has been performed by using both 3D electro-thermal FEM simulations made with COMSOL Multyphisics® and experimental measurements. The first result we discuss is the good agreement between 3D FEM simulations of the device, made with COMSOL Multiphysics®, and the experiments, with a maximum error of 2.9% for He flow rate of 9 sccm and around 1.8% for the N2 carrier gas at each considered flow rate. We have demonstrated that the Spice model can reproduce very well the FEM simulations for all the gas flow rates and the operating power values taken into consideration, using simulation parameters extracted from FEM data itself. Results of the Spice model compare well also with the real behavior of a TCD device for both the used gases, using parameters either extracted from FEM simulations or calibrated with experimental measurements, with a maximum error of 0.9% for the He flow rate of 0.29 sccm and a maximum error of 0.8% for the N2 flow rate of 10.3 sccm. The novelty of the proposed approach is to provide a useful instrument for the electronic designer who wants to incorporate a Spice electro-thermal model in a simulation environment. The TCD can initially be simulated with an electro-thermal FEM model for a reduced number of operating conditions, then the Spice model can be calibrated and exploited for the electronic design. After device production, the Spice model can eventually be optimized using the experimental results, thus improving the accuracy of the whole electronic circuit simulation.
    No preview · Article · May 2012 · Sensors and Actuators A Physical
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    ABSTRACT: The aim of this paper is to present an acquisition system and experimental measurements of a new micromachined Thermal Conductivity Detector (μTCD), applied downstream of a gas-chromatography (GC) system. We describe a simple and innovative electronics for sensor control and data acquisition, outlining its resistance control, native imbalance compensation and automatic gain control (AGC) algorithm. Measurements and sensitivity tests have been carried out by connecting our TCD and acquisition system downstream of the microfluidic section and GC column of a commercial GC system. Comparing the results with those of a complete commercial GC system we observed a similar response and noise. Sensitivity measurements on toluene masses gave very good results, having observed a sensitivity of 15.2±0.6 μVs/ng. This high sensitivity will enable the use of the μTCD in many portable applications like in-line quality control, industrial security and safety. We also show the good operation of the AGC algorithm.
    Full-text · Conference Paper · May 2012
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    ABSTRACT: A new detection system for ATS and their precursors has been designed and a bench-top demonstrator has been realized. A test campaign has been performed in order to assess the overall system behavior, and the results confirmed the feasibility of this type of device.
    No preview · Conference Paper · Feb 2012
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    ABSTRACT: A post implantation microwave annealing technique has been used for the electrical activation of Al+ implanted ions in semi-insulating 4H-SiC. The annealing temperatures have been 2000-2100 degrees C. The implanted Al concentration has been varied from 5 x 10(19) to 8 x cm(-3). A minimum resistivity of 2 x 10(-2) Omega.cm and about 70% electrical activation of the implanted Al has been measured at room temperature for an implanted Al concentration of 8 x 10(2) cm(-3) and a microwave annealing at 2100 degrees C for 30 s.
    No preview · Conference Paper · Jan 2012
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    ABSTRACT: For the successful miniaturization of integrated fluidic devices, it is desirable to have a reliable non-leaking microvalve that can be used in various environments, in a wide temperature range and that is chemically inert. This work describes the design, fabrication and characterization of an innovative pneumatically driven microvalve based on an SU-8 actuating membrane, to be employed in high-speed gas chromatographic (HSGC) applications. In this scenario, a critical constrain is the volume of the microvalve, which needs to be as small as possible to reduce the response time of the chromatograph. The experimental characterization of the fabricated SU-8 microvalves indicates very good sealing properties and low actuating pressures, under different working conditions and in spite of the reduced volume.
    No preview · Article · Jan 2012
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    ABSTRACT: In this work an ion source for IMS (Ion Mobility Spectrometry) and FAIMS (Field Asymmetric Ion Mobility Spectrometry) systems is described. The ion source exploits the field ionization principle (non-uniform strong electric field). Moreover, the designed ion source takes into account a heating system to control the overall temperature, which can affect the mobility of the ions and the selectivity of the entire system. After a literature search, we designed a simple geometry with the aim to understand the basic principles for developing an effective and efficient ion source for portable IMS and FAIMS systems. The main aspects that have been considered are: integrability, portability, operation at ambient pressure, low voltages, lifetime, efficiency and cost. 2D simulations have been performed using COMSOL Multiphysics® 4.0.
    No preview · Conference Paper · Jul 2011
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    ABSTRACT: In this paper we present a micromachined Thermal Conductivity Detector (TCD), based on the Ultra Low Power (ULP) technology. The device has been electrically characterized with different Helium gas flows, via a microfluidic experimental setup. Extraction of global thermo-electric parameters, exploited for the development of an electro-thermal Spice model, has been performed directly from the experimental measurements and from 3-D electro-thermal FEM simulations of the device. The resulting Spice model agrees very well with the measurements, with a maximum error less than 0.22%.
    No preview · Conference Paper · May 2011
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    ABSTRACT: In this study a pyrolyzed photoresist film that has been used for protecting the implanted surface of a 4H-SiC wafer during post implantation annealing at 1800-1950 °C has preserved on the wafer surface and used for the fabrication of ohmic contact pads on P+ implanted areas. The carbon film has been patterned by using a RIE O2-based plasma. A specific contact resistance of 9  10 5 cm2 has been obtained on P+ 1  1020 cm 3 implanted 4H-SiC. Micro-Raman characterizations show that the carbon cap is formed of a nano-crystalline graphitic phase.
    No preview · Article · Mar 2011 · Materials Science Forum
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    ABSTRACT: Abstract-An electronic system based on a microcontroller architecture, devoted to interfacing a three-terminal, ultralow power (ULP) Metal OXide (MOX) gas sensor is presented. The sensor features a novel three-terminal configuration where the microheater is not galvanically isolated with respect to the MOX sensor. The system provides both control of the operating temperature and management of the acquired data. A Pulse Width Modulation (PWM) signal with variable duty cycle is used to provide power to the heating resistor in order to set the desired operating temperature. The heating resistance value is measured in the range (100-300) Ω with a relative error of less than 1%. The circuit devoted to measuring the gas concentration is based on a logarithmic amplifier which measures the current flowing in the sensing layer of the sensor. The measurand range is 30 nA to 60 mA and the relative error of the measured current is less than 0.6%. The data acquisition system was successfully tested by acquiring data of a three-terminal ULP gas sensor located in an automatically controlled environmental chamber under benzene and NO<sub>2</sub> flow.
    No preview · Article · Feb 2011 · IEEE Transactions on Instrumentation and Measurement

  • No preview · Conference Paper · Jan 2011
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    ABSTRACT: In this work a MEMS gas calibration source will be presented. For reliable and quantitative automatic measures over long periods of time, gas sensors and micro-analytical-systems require periodical calibrations. The authors developed an innovative solution based on a liquid reservoir and silicon micromachined nanochannels. To provide low emission rates of highly volatile substances (e.g. toluene) in the ng/min range, micro-channels have millimetric length, micrometric width and nanometric depth, with a typical cross-section of 0.5 μm2. Prototypal devices with different channel dimensions, shapes and numbers have been built and functionally characterized. Technological fabrication process flow and characterization results will be shown, and the results will be compared with commercially available permeation tubes.
    Preview · Article · Dec 2010 · Procedia Engineering

Publication Stats

701 Citations
71.04 Total Impact Points

Institutions

  • 2004-2014
    • INO - Istituto Nazionale di Ottica
      Florens, Tuscany, Italy
    • Jahangirnagar University
      • Department of Physics
      Mujib City, Dhaka, Bangladesh
  • 2007
    • National Research Council
      • Institute for Microelectronics and Microsystems IMM
      Roma, Latium, Italy
  • 2005
    • Università degli Studi di Perugia
      • Department of Electronic and Information Engineering
      Perugia, Umbria, Italy