The E-nose system reported is designed to address the problem of early and distributed detection of dangerous gas mixtures. It is made of a selection of Commercial Off-The-Shelf (COTS) sensors, facing a small volume chamber, whose signals are conditioned and sampled by a multifunction board connected to a personal computer. A program, implementing efficient Support Vector Machine and least square model algorithms, executes the gas classification, the concentration estimation and warns about set risk thresholds overcoming. The system training was performed in laboratory, over a wide range of concentrations in air of: methane, hexane, pentane, and hydrogen sulfide. Other boundary conditions, such as oxygen concentration, temperature and RH are also taken into account. The overall cost of the system can be made very low, adopting an embedded architecture approach, allowing to overcome the limitations of the monitoring systems deployment inside refinery plants due to the high costs of traditional GC systems.

CTO powders and thin films have been prepared by a sol-gel route and subsequent thermal treatment at low temperature (<= 400 degrees C). The humidity characteristics of CTO thin films have been investigated. Results reported have shown that the humidity behaviour is related to the intergranulary porosity of the films. The Cr/Ti ratio and the role of alkaline impurities (Li+) was also studied with aim to clarify the mechanism of the surface conduction of CTO films in the presence of water vapor.

Li-doped iron oxide thin films deposited on a porous ceramic substrate by a liquid-phase method (LPD) were investigated as humidity sensors. Large variations in the resistance, up to about 4–5 order of magnitude, were observed by changing the relative humidity (RH) between 10 and 90%. The investigated sensors show a quick and reversible response to cyclic variations in the RH. The effects of pretreatment and Li content were investigated. The role of Li on the response to water vapour of iron oxide thin films is discussed.

Spectrophotometry and photoluminescence (PL) are used to investigate the optical properties and photodegradation of thin films of pyrromethene 580 dispersed in polycarbonate (PC). The films spin-coated on glass act as asymmetric planar waveguides and excited with blue light yield a linearly polarized emission whose color changes according to the film thickness.

An electrochemical method used to obtain aluminum(III)-8 hydroxyquinoline (Alq3) blended into poly(N-vinylcarbazole) (PVK) matrix is described. The PVK-Alq3 blends show an intense green photoluminescence whose intensity increases by adding a small percentage of a substituted coumarin to the PVK-Alq3 solution. The material can easily be spin-coated to obtain homogeneous luminescent thin films suitable for optoelectronic applications. Spectrophotometry in the uv-vis-ir range, photoluminescence, and lifetime measurements are used to characterize the PVK-Alq3 films.

The optical properties of thin films of PVK-Alq3 are examined by means of spectrophotometry in the UV-VIS-NIR. Photoluminescence (PL) measurements indicate that the polymer films deposited on glass substrates behave as asymmetrical planar waveguides for the emitted light. The waveguided luminescence shrinks and change color with respect to the non-waveguided emission. Stronger changes in the luminescence features are observed using a microcavity configuration, obtained by spin-coating PVK-Alq3 on an inorganic Distributed Bragg Reflector (DBR) and by vacuum-depositing a thick aluminum layer on the top of the polymer film.