An Array of MOX Sensors and ANNs to Assess Grated Parmigiano Reggiano Cheese Packs' Compliance with CFPR Guidelines.

Parmigiano Reggiano cheese is one of the most appreciated Italian foods on account of its high nutrient content and taste. Due to its high cost, these characteristics make this product subject to counterfeiting in different forms. In this study, an approach based on an array of gas sensors has been employed to assess if it was possible to distinguish different samples based on their aroma.

Nanostructured MOS Sensor for the Detection, Follow up, and Threshold Pursuing of Development in Milk Samples.

Food poisoning is still the first cause of hospitalization worldwide and the most common microbial agent, , is the most commonly reported gastrointestinal disease in humans in the EU (European Union) as is reported by the European Union One Health 2018 Zoonoses Report styled by the EFSA (European Food Safety Authority) and ECDC (European Center for Disease Prevention and Control). One of the vehicles of transmission of this disease is milk. Nanostructured MOS (Metal Oxide Semiconductor) sensors have extensively demonstrated their ability to reveal the presence and follow the development of microbial species.

UV-Enhanced Humidity Sensing of Chitosan-SnO Hybrid Nanowires.

The surface of SnO nanowires was functionalized by chitosan for the development of room-temperature conductometric humidity sensors. SnO nanowires were synthesized by the seed-mediated physical-vapor-deposition (PVD) method. Chitosan layers were deposited on top of the SnO nanowires by spin coating.

Nanomaterial Gas Sensors for Online Monitoring System of Fruit Jams.

Jams are appreciated worldwide and have become a growing market, due to the greater attention paid by consumers for healthy food. The selected products for this study represent a segment of the European market that addresses natural products without added sucrose or with a low content of natural sugars. This study aims to identify volatile organic compounds (VOCs) that characterize three flavors of fruit and five recipes using gas chromatography-mass spectrometry (GC-MS) and solid-phase micro-extraction (SPME) analysis.

Investigation of Reduced Graphene Oxide and a Nb-Doped TiO Nanotube Hybrid Structure To Improve the Gas-Sensing Response and Selectivity.

The precise detection of flammable and explosive gases and vapors remains an important issue because of the increasing demand for renewable energy sources and safety requirements in industrial processes. Metal oxides (TiO, SnO, ZnO, etc.) are very attractive materials for the manufacturing of chemical gas sensors.

Sensitivity-Selectivity Trade-Offs in Surface Ionization Gas Detection.

Surface ionization (SI) provides a simple, sensitive, and selective method for the detection of high-proton affinity substances, such as organic decay products, medical and illicit drugs as well as a range of other hazardous materials. Tests on different kinds of SI sensors showed that the sensitivity and selectivity of such devices is not only dependent on the stoichiometry and nanomorphology of the emitter materials, but also on the shape of the electrode configurations that are used to read out the SI signals. Whereas, in parallel-plate capacitor devices, different kinds of emitter materials exhibit a high level of amine-selectivity, MEMS (micro-electro-mechanical-systems) and NEMS (nanowire) versions of SI sensors employing the same kinds of emitter materials provide significantly higher sensitivity, however, at the expense of a reduced chemical selectivity.

Application of a Novel S3 Nanowire Gas Sensor Device in Parallel with GC-MS for the Identification of Rind Percentage of Grated Parmigiano Reggiano.

Parmigiano Reggiano cheese is one of the most appreciated and consumed foods worldwide, especially in Italy, for its high content of nutrients and taste. However, these characteristics make this product subject to counterfeiting in different forms. In this study, a novel method based on an electronic nose has been developed to investigate the potentiality of this tool to distinguish rind percentages in grated Parmigiano Reggiano packages that should be lower than 18%.

Self-Test Procedures for Gas Sensors Embedded in Microreactor Systems.

Metal oxide (MOX) gas sensors sensitively respond to a wide variety of combustible, explosive and poisonous gases. However, due to the lack of a built-in self-test capability, MOX gas sensors have not yet been able to penetrate safety-critical applications. In the present work we report on gas sensing experiments performed on MOX gas sensors embedded in ceramic micro-reaction chambers.

Transfer of CVD-grown graphene for room temperature gas sensors.

An easy transfer procedure to obtain graphene-based gas sensing devices operating at room temperature (RT) is presented. Starting from chemical vapor deposition-grown graphene on copper foil, we obtained single layer graphene which could be transferred onto arbitrary substrates. In particular, we placed single layer graphene on top of a SiO/Si substrate with pre-patterned Pt electrodes to realize a chemiresistor gas sensor able to operate at RT.

Metal oxide nanostructures: preparation, characterization and functional applications as chemical sensors.

Preparation and characterization of different metal oxide (NiO, WO, ZnO, SnO and NbO) nanostructures for chemical sensing are presented. p-Type (NiO) and n-type (WO, SnO, ZnO and NbO) metal oxide nanostructures were grown on alumina substrates using evaporation-condensation, thermal oxidation and hydrothermal techniques. Surface morphologies and crystal structures were investigated through scanning electron microscopy and Raman spectroscopy.

Metal Oxide Nanowire Preparation and Their Integration into Chemical Sensing Devices at the SENSOR Lab in Brescia.

Metal oxide 1D nanowires are probably the most promising structures to develop cheap stable and selective chemical sensors. The purpose of this contribution is to review almost two-decades of research activity at the Sensor Lab Brescia on their preparation during by vapor solid (-type In₂O₃, ZnO), vapor liquid solid (-type SnO and -type NiO) and thermal evaporation and oxidation (-type ZnO, WO₃ and -type CuO) methods. For each material we've assessed the chemical sensing performance in relation to the preparation conditions and established a rank in the detection of environmental and industrial pollutants: SnO₂ nanowires were effective in DMMP detection, ZnO nanowires in NO₂, acetone and ethanol detection, WO₃ for ammonia and CuO for ozone.

A Novel MOS Nanowire Gas Sensor Device (S3) and GC-MS-Based Approach for the Characterization of Grated Parmigiano Reggiano Cheese.

To determine the originality of a typical Italian Parmigiano Reggiano cheese, it is crucial to define and characterize its quality, ripening period, and geographical origin. Different analytical techniques have been applied aimed at studying the organoleptic and characteristic volatile organic compounds (VOCs) profile of this cheese. However, most of the classical methods are time consuming and costly.

A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors.

A hybrid nanostructure based on reduced graphene oxide and ZnO has been obtained for the detection of volatile organic compounds. The sensing properties of the hybrid structure have been studied for different concentrations of ethanol and acetone. The response of the hybrid material is significantly higher compared to pristine ZnO nanostructures.

Nickel oxide nanowires: vapor liquid solid synthesis and integration into a gas sensing device.

In the field of advanced sensor technology, metal oxide nanostructures are promising materials due to their high charge carrier mobility, easy fabrication and excellent stability. Among all the metal oxide semiconductors, nickel oxide (NiO) is a p-type semiconductor with a wide band gap and excellent optical, electrical and magnetic properties, which has not been much investigated. Herein, we report the growth of NiO nanowires by using the vapor liquid solid (VLS) technique for gas sensing applications.

A Player Often Neglected: Electrochemical Comprehensive Analysis of Counter Electrodes for Quantum Dot Solar Cells.

The role played by the counter electrode (CE) in quantum dot sensitized solar cells (QDSSCs) is crucial: it is indeed responsible for catalyzing the regeneration of the redox electrolyte after its action to take back the oxidized light harvesters to the ground state, thus keeping the device active and stable. The activity of CE is moreover directly related to the fill factor and short circuit current through the resistance of the interface electrode-electrolyte that affects the series resistance of the cell. Despite that, too few efforts have been devoted to a comprehensive analysis of this important device component.

ZnO@SnO2 engineered composite photoanodes for dye sensitized solar cells.

Layered multi-oxide concept was applied for fabrication of photoanodes for dye-sensitized solar cells based on ZnO and SnO2, capitalizing on the beneficial properties of each oxide. The effect of different combinations of ZnO@SnO2 layers was investigated, aimed at exploiting the high carrier mobility provided by the ZnO and the higher stability under UV irradiation pledged by SnO2. Bi-oxide photoanodes performed much better in terms of photoconversion efficiency (PCE) (4.

Ultrathin Gas Permeable Oxide Membranes for Chemical Sensing: Nanoporous Ta₂O₅ Test Study.

Conductometric gas sensors made of gas permeable metal oxide ultrathin membranes can combine the functions of a selective filter, preconcentrator, and sensing element and thus can be particularly promising for the active sampling of diluted analytes. Here we report a case study of the electron transport and gas sensing properties of such a membrane made of nanoporous Ta₂O₅. These membranes demonstrated a noticeable chemical sensitivity toward ammonia, ethanol, and acetone at high temperatures above 400 °C.

Visible electroluminescence from a ZnO nanowires/p-GaN heterojunction light emitting diode.

In the current paper we apply catalyst assisted vapour phase growth technique to grow ZnO nanowires (ZnO nws) on p-GaN thin film obtaining EL emission in reverse bias regime. ZnO based LED represents a promising alternative to III-nitride LEDs, as in free devices: the potential is in near-UV emission and visible emission. For ZnO, the use of nanowires ensures good crystallinity of the ZnO, and improved light extraction from the interface when the nanowires are vertically aligned.

Optical, electrical, and electromechanical properties of hybrid graphene/carbon nanotube films.

By combining a graphene layer and aligned multiwalled carbon nanotube (MWNT) sheets in two different configurations, i) graphene on the top of MWNTs and ii) MWNTs on the top of the graphene, it is demonstrated that optical, electrical, and electromechanical properties of the resulting hybrid films depend on configurations.

Synthesis and electrochemical study of a hybrid structure based on PDMS-TEOS and titania nanotubes for biomedical applications.

Metallic implants and devices are widely used in the orthopedic and orthodontic clinical areas. However, several problems regarding their adhesion with the living tissues and inflammatory responses due to the release of metallic ions to the medium have been reported. The modification of the metallic surfaces and the use of biocompatible protective coatings are two approaches to solve such issues.

Integration of ZnO and CuO nanowires into a thermoelectric module.

Zinc oxide (ZnO, n-type) and copper oxide (CuO, p-type) nanowires have been synthesized and preliminarily investigated as innovative materials for the fabrication of a proof-of-concept thermoelectric device. The Seebeck coefficients, electrical conductivity and thermoelectric power factors (TPF) of both semiconductor materials have been determined independently using a custom experimental set-up, leading to results in agreement with available literature with potential improvement. Combining bundles of ZnO and CuO nanowires in a series of five thermocouples on alumina leads to a macroscopic prototype of a planar thermoelectric generator (TEG) unit.

Effect of blocking layer to boost photoconversion efficiency in ZnO dye-sensitized solar cells.

The effect of a ZnO compact blocking layer (BL) in dye-sensitized solar cells (DSSCs) based on ZnO photoanodes is investigated. BL is generated through spray deposition onto fluorine-doped tin oxide (FTO) conducting glass before the deposition of a ZnO active layer. The functional properties of dye-sensitized solar cells (DSSCs) are then investigated as a function of the thickness of the BL for two different kinds of ZnO active layer, i.

TiO2 nanotubes: recent advances in synthesis and gas sensing properties.

Synthesis--particularly by electrochemical anodization-, growth mechanism and chemical sensing properties of pure, doped and mixed titania tubular arrays are reviewed. The first part deals on how anodization parameters affect the size, shape and morphology of titania nanotubes. In the second part fabrication of sensing devices based on titania nanotubes is presented, together with their most notable gas sensing performances.

Thermally oxidized zinc oxide nanowires for use as chemical sensors.

Zinc oxide (ZnO) mat-based conductometric devices were fabricated using a thermal oxidation technique. A metallic zinc layer was deposited on the alumina transducer and then oxidized in a controlled atmosphere, in order to obtain ZnO nanostructures. Two different batches of sensors have been prepared, and their sensing performances have been evaluated towards oxidizing and reducing gases.