Electrical Characterization of Microstrip Resonators Based on Nanostructured Sensing Materials

In this paper is reported the development of microstrip resonators working in the frequency range of 3–6, GHz and their employment in the investigation of the sensing properties of nanostructured materials towards gas. The materials are deposited as films on the gap of the resonators by drop coating aqueous solutions of Ag@α-Fe2O3 nanocomposite having a core–shell structure. Here are reported sensing data about humidity monitoring in the range from 0 to 70%. The increase of humidity value brings to a large frequency shift of the resonance one. The good characteristics of the fabricated device suggest its promising use as humidity sensor

Development of an Arduino shield for measurement and characterization of resistive sensors

In this paper is reported the activity regarding the development of a measurement system for Arduino DUE environment, able to perform electrical characterization of resistive sensing films under UV irradiation and to send data by USB and by Bluetooth protocols. The system is composed of two modular boards (Shields) the first for the electrical characterization, the latter for Bluetooth connection. The resistance variation of the sensor can be evaluated by properly choosing the capacitance value and by measuring the period (frequency) of a custom inverter-based oscillator. The GUI and the developed firmware are able to perform the real time monitoring of the sensor responses. The developed shield is able to measure the response of up to six sensors under UV radiation by means of LED devices. The GUIs were developed for the connections with Personal Computer, Tablet and Smartphone. The measurement apparatus was calibrated by measuring commercial resistors and then validated by characterizing Indium Oxides sensing films deposited by screen-printing technique on alumina substrates with platinum interdigitated electrodes on parallel configuration

Pt-TiO2/MWCNTs Hybrid Composites for Monitoring Low Hydrogen Concentrations in Air

Hydrogen is a valuable fuel for the next energy scenario. Unfortunately, hydrogen is highly flammable at concentrations higher than 4% in air. This aspect makes the monitoring of H2 leaks an essential issue for safety reasons, especially in the transportation field. In this paper, nanocomposites based on Pt-doped TiO2/multiwalled carbon nanotubes (MWCNTs) have been introduced as sensitive materials for H2 at low temperatures. Pt-TiO2/MWNTs nanocomposites with different composition have been prepared by a simple wet chemical procedure and their morphological, microstructural and electrical properties were investigated. Resistive thick-film devices have been fabricated printing the hybrid nanocomposites on alumina substrates provided with Pt interdigitated electrodes. Electrical tests in air have shown that embedding MWCNTs in the TiO2 matrix modify markedly the electrical conductivity, providing a means to decrease the resistance of the sensing layer. Pt acts as a catalytic additive. Pt-TiO2/MWNTs-based sensors were found to be sensitive to hydrogen at concentrations between 0.5 and 3% in air, satisfying the requisites for practical applications in hydrogen leak detection devices

Defining Product Lifecycle Management: A Journey across Features, Definitions, and Concepts

Product lifecycle management (PLM) has become more important in companies providing technologies and methodologies to manage data, information, and knowledge along the whole product lifecycle. In recent years, several authors have argued about PLM using a managerial or a technological view. The paper analyses these studies and integrates different author's points of view using focus groups, blogs, and face-to-face meetings in a university community of practice. Three sets of features (i.e., managerial, technological, and collaborative ones) have been used to review the existing definitions shared between academic and industrial ones and to propose an extended PLM definition describing its key concepts. The paper is a useful reference for managers and academics who want to have a clear and critical understanding of PLM using a unique source to collect lines of evidence on several PLM definitions, features, and concepts

Inkjet-Printed Interdigitated Capacitors for Sensing Applications: Temperature-Dependent Electrical Characterization at Cryogenic Temperatures down to 20 K

Microwave transducers are widely used for sensing applications in areas such as gas sensing and microfluidics. Inkjet printing technology has been proposed as a promising method for fabricating such devices due to its capability to produce complex patterns and geometries with high precision. In this work, the temperature-dependent electrical properties of an inkjet-printed single-port interdigitated capacitor (IDC) were investigated at cryogenic temperatures down to 20 K. The IDC was designed and fabricated using inkjet printing technology, while its reflection coefficient was measured using a vector network analyzer in a cryogenic measurement setup and then transformed into the corresponding admittance. The resonant frequency and quality factor (Q-factor) of the IDC were extracted as functions of the temperature and their sensitivity was evaluated. The results showed that the resonant frequency shifted to higher frequencies as the temperature was reduced, while the Q-factor increased as the temperature decreased. The trends and observations in the temperature-dependent electrical properties of the IDC are discussed and analyzed in this paper, and are expected to be useful in future advancement of the design and optimization of inkjet-printed microwave transducers for sensing applications and cryogenic electronics

UV light-enhanced NO2 Sensing by Mesoporous In2O3: Interpretation of Results by a new Sensing Model

The light-enhanced NO2 sensing behavior of mesoporous In2O3 is measured and interpreted by means of a new sensing model. The model aims at explaining (i) the drop in electronic resistance of n-type semiconducting In2O3 under UV light exposure, (ii) the light-enhanced reaction to oxidizing gases, and (iii) the faster reaction and regeneration in mesoporous In2O3 as compared to non-porous material. Contrary to the conventional double Schottky model the dominating factor for the change in resistance is a change of oxygen vacancy donor states (0.18 eV below the conduction band) in the bulk phase due to photoreduction, instead of chemisorption. For the faster reaction and regeneration we propose an explanation based on enhanced oxygen diffusion in the In2O3 crystal lattice, specifically dominant in the mesoporous structure. The response of ordered mesoporous In2O3 to NO2 is stronger than in case of unstructured bulk material (with an average grain size of ca. 40 nm). The reaction is significantly accelerated by illuminating the samples with UV light. However, the response of the mesoporous material is weaker in the illuminated case

Mechanistic Model for UV light-enhanced NO2 Sensing utilizing Ordered Mesoporous In2O3

Results on light-enhanced NO2 sensing utilizing ordered mesoporous In2O3 are presented and interpreted by means of a new sensing model for ordered mesoporous indium oxide (In2O3). This model aims to explain the drop in electronic resistance of n-type semiconducting In2O3 under UV light exposure as well as the light-enhanced sensing properties to oxidizing gases. Compared to the conventional double Schottky model the dominating factor for the resistance change is a change of oxygen vacancy donor states in the bulk phase due to photoreduction. Comparison of conductivity measurements with varying oxygen partial pressure for ordered mesoporous and non-structured material shows an accumulative behavior in the case of the mesoporous material which can be related to faster photo reduction caused by the nanostructure. IR measurements reveal a donor level of 0.18 eV below the conduction band attributed to oxygen vacancies. The unique properties resulting from the structure allow low-temperature sensing of NO2; especially the recovery times are significantly shorter for the mesoporous material