Nowadays, the necessity of safeguarded environments is stronger than ever. The defence of public areas against terroristic threats requires intelligent security assistance systems that comprise state-of-the-art surveillance technology to localize persons with hazardous materials. The recent progress in the detection of hazardous materials by a new generation of chemical sensors leads to an incr...

A major research effort has been devoted over the years for the development of chemical sensors for the detection of chemical and explosive vapors. However, the deployment of such chemical sensors will require the use of multiple sensors (probably tens of sensors) in a sensor package to achieve selective detection. In order to keep the overall detector unit small, miniature sensors with suffici...

A significant need exists for in situ sensors that can measure chemical species involved in the major processes of primary production (photosynthesis and chemosynthesis) and respiration. Some key chemical species are O2, nutrients (N and P), micronutrients (metals), pCO2, dissolved inorganic carbon (DIC), pH, and sulfide. Sensors need to have excellent detection limits, precision, selectivity, ...

A review of three commonly used classes of chemical sensor technologies as applicable to implementation in portable, handheld field instruments is presented. Solid-state gas and chemical sensors have long been heralded as the solution to a wide variety of portable chemical sensing system applications. However, advances in optical sensing technology have reduced the size of supporting infrastruc...

The development of simple and low-cost chemical sensors is critically important for improving human life. Many types of chemical sensors have been developed. Among them, the chemiresistive sensors receive particular attention because of their simple structure, the ease of high precise measurement and the low cost. This review mainly focuses on carbon nanotube (CNT)-based chemiresistive sensors....

Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has advantages of high sensitivity, low decreased e...

This paper addresses the need for a broad-base signal conditioning module designed to process chemical sensor signals in such a way that the output of the conditioning circuits ensures similar baseline and dynamic range, regardless of fabrication variation and sensor drift. These baseline compensation circuits are demonstrated in the context of processing resistance changes from composite polym...

Reported by Jay Wackerly November 1, 2004 INTRODUCTION A chemical sensor is a molecule that interacts with another molecule giving a measurable signal in response. Chemical sensors based on conjugated polymers have received a great deal of attention due to their ability to detect analytes at low concentrations. Fluorescence quenching provides an effective means for detection because of the extr...

Nanotechnology-based microscopic robots could provide accurate in vivo measurement of chemicals in the bloodstream for detailed biological research and as an aid to medical treatment. Quantitative performance estimates of such devices require models of how chemicals in the blood diffuse to the devices. This paper models microscopic robots and red blood cells (erythrocytes) in capillaries using ...

Optical chemical sensors have promoted escalating interest in the determination of various pollutants in the environment, which are creating toxicity and may cause serious health problems. This review paper focuses particularly on the recent progress and developments in this field; the working principles and basic classes of optical chemical sensors have been briefly described.