Exhaled breath is a body secretion, and the sampling process of this is simple and cost effective. It can be non-invasively collected for diagnostic procedures. Variations in the chemical composition of exhaled breath resulting from gaseous exchange in the extensive capillary network of the body are proposed to be associated with pathophysiological changes. In light of the foreseeable potential...

The Qualitative Modelling and Interpretation (QMi) system translates noisy sensor data into a qualitative description of the underlying behaviorof a chemical plant and uses this information together with qualitative models to identify faults and operating regimes. Qualitative models of normal and faulty equipment are simulated to describe the range of possible behaviors in a chemical plant with...

Owing to their extraordinary electrical, chemical, optical, mechanical and structural properties, graphene and its derivatives have stimulated exploding interests in their sensor applications ever since the first isolation of free-standing graphene sheets in year 2004. This article critically and comprehensively reviews the emerging graphene-based electrochemical sensors, electronic sensors, op...

G1 and G2 fluorene dendrimers with naphthalene termini were synthesized as a fluorescence turn-on type chemical sensor for vitamin K4. The fluorene dendrimers were prepared by Williamson ether reaction between the fluorene core with dihydroxy groups and dendritic naphthalene segments with methylene chloride by a convergent method. We investigated the relationship between the dendrimer generatio...

A novel approach for multicomponent patterning metal/metal oxide nanoparticles on graphene was developed, which involves region-specific plasma treatment, followed by region-selective substrate-enhanced electroless deposition of Au nanoparticles and solution alkalization of ferrous chloride tetrahydrate in the presence of ammonia into Fe3O4 nanoparticles. The resultant Fe3O4/Au multicomponent m...

An inexpensive hand-held device for analysis of colorimetric sensor arrays (CSAs) has been developed. The device makes use of a contact image sensor (CIS), technology commonly used in business card scanners, to rapidly collect low-noise colorimetric data for chemical sensing. The lack of moving parts and insensitivity to vibration allow for lower noise and improved scan rates compared to other ...

The fabrication of SiC MEMS pressure sensor based on novel vacuum-sealed method is presented in this paper. The sensor was fabricated using surface micromachining. Due to its excellent mechanical properties and high chemical resistance, PECVD (Plasma Enhanced Chemical Vapor Deposition) SiC was chosen as structural material. Polyimide is the sacrificial layer which solve stiction problem in proc...

In this investigation, we propose and experimentally demonstrate a method for measuring the refractive index (RI) of liquid organic chemicals. The scheme is based on a single-mode fiber (SMF) sensor and an optical time-domain reflectometer (OTDR). Here, due to the different reflectance (R) between the SMF and organic liquid chemicals, the reflected power level of the backscattering light (BSL) ...

Nickel oxide has been widely used in chemical sensing applications, because it has an excellent p-type semiconducting property with high chemical stability. Here, we present a novel technique of fabricating three-dimensional porous nitrogen-doped nickel oxide nanosheets as a highly sensitive NO₂ sensor. The elaborate nanostructure was prepared by a simple and effective hydrothermal synthesis me...

We explore capacitanceand conductance-based detection of trace chemical vapors using single-walled carbon nanotubes (SWNTs). We find that conductance detection is susceptible to such problems as large 1/f noise and incomplete sensor recovery, which are primarily artifacts of a charge-based transduction mechanism. Capacitance detection, dominated by dielectric effects, is less sensitive to charg...