thin films of sno2 nanowires were successfully prepared by using chemical vapor deposition (cvd) process on quartz substrates. afterwards, a thin  layer of palladium (pd) as a catalyst was coated on top of nanowires. for the deposition of pd, a simple and low cost technique of spray pyrolysis was employed, which caused an intensive enhancement on the sensing response of fabricated sensors. prep...

in this work, hierarchical wo3 core-shell microspheres were synthesized via a facile template-free precipitation method. gas sensing properties of the synthesized powder to acetone and some other volatile organic compounds were comparatively investigated with commercial wo3 nanoparticles. the synthesized and commercial powders were characterized by x-ray diffraction, scanning electron microscop...

One concern in using photonic band-gap fiber (PBGF) as a gas sensor is the response time. In this type of the gas sensors, response time is the time required for gas to diffuse into the hollow-core. So considering a large hollow-core PBGF (HC-PBGF), the response time can be significantly reduced. But in the large HC-PBGF, the fundamental issue is the presence of higher order modes (HOMs). Somet...

a dissolved methane sensor based on silicone tube was designed, constructed and optimized.the silicone tube diameter, silicone tube length and helium flow rate (as the carrier gas(were considered as process parameters to be optimized.a continuous stream of helium (50 ml/min) was directed through the tubing, sweeping out the dissolved methane which diffused through the walls of the tubing from t...

A multi-sensor system is a chemical sensor system which quantitatively and qualitatively records gases with a combination of cross-sensitive gas sensor arrays and pattern recognition software. This paper addresses the issue of data analysis for identification of gases in a gas sensor array. We introduce a software tool for gas sensor array configuration and simulation. It concerns thereby about...

great effect of three way catalytic convertor (twc) performance on oxygen sensor output voltage has made the sensor (located after catalyst) as the main signal in almost all today’s twc monitoring algorithms. in this paper output voltage of nonlinear oxygen sensor is estimated using a nonlinear autoregressive with exogenous inputs (narx) model. the estimation uses ecu calculated exhaust gas flo...

In this work, a new type of optical fiber based chemical sensor, the sub-nanoliter sample cell (SNSC) based gas sensor, is described and compared to existing sensors designs in the literature. This novel SNSC gas sensor is shown to have the capability of gas detection with a cell volume in the sub-nanoliter range. Experimental results for various configurations of the sensor design are presente...