On the Realization of Photo-conductive Paints

In a country like India where the sunlight is available throughout the year, a large opportunity awaits in realizing it to the full potential. Very large scale projects are being undertaken by the Government to realize this goal, and the electrification of the Cochin Airport through solar cells is the finest example.

When it comes to solar power, the main challenge lies in the cost of installation. People seldom look into its long time value and are often caught in huge investment they have to make. In this scenario, it is vital, that some cost cutting technology come to help. And one proposal here is to develop a photo-conductive paint. The idea here is to develop a paint, with a chemical composition such that, it can absorb the ambient sunlight. The paint shall be composed of nano-particles which will in directly help in the conduction of the electricity.

A proposed idea helps you to apply the paint such that it can supplement the power line to your home.

Courtesy : http://www.stewmac.com/

eNose - Design, Applications and Challenges

This article is a republished version of the Technical Article Board at SSET

Abstract

Sensors are widely used today to collect local databases on various parameters. In this article, a sensor which can measure olfactory(smell) signals is presented. The eNose or the Electronic Nose is a biologically inspired sensor, having origins in the functioning of the mammalian olfactory system. A review of the various sensing techniques along with the classification methods and applications are presented.

Introduction

The term ``electronic nose" was coined in 1988 by Gardner and Bartlett wherein they defined e-nose (EN) as ``an instrument which comprises an array of electronic chemical sensors with partial specificity and appropriate pattern recognition system, capable of recognizing simple, or complex odours". The design of the sensor replicates the functioning of the mammalian olfactory system, although it has some limitations. For instance, EN's are more application specific, that is the sensor available for bio-sensing cannot be employed for food testing or environment monitoring. Recently, chemical based sensors are employed in measuring food quality and in select beverages and fast foods. The figure below illustrates the broad parts of the eNose.

How it is done : Components that are used

The eNose consists of the following components :

• Multiple Sensor Array
• Data Acquisition System
• Pattern Recognition System

There are different sensing mechanisms for the functioning of the eNose, viz. Optical, Mass and Ion Mobility based, Gas Chromatography based, Infrared Spectroscopy based, Chemical Sensors. Of these the Chemical sensors are the most popular and widely employed, as it is possible to tailor various parameters and due to its close resemblance to mammalian olfaction. These are again classifies as MOS, MOSFET, surface and bulk acoustic wave, and conductive polymers.

Role of Nanomaterials

The preferred choice of sensor is to employ nano-structures which offer many advantages such as low cost, compact size, low power consumption, and faster response. With the advancement in microelectromechanical systems (MEMS), nanoelectromechanical systems (NEMS) very large-scale integration (VLSI), and nanoscience various novel nanostructures are successfully being employed in the fabrication of EN devices.

Reference : Ramgir, Niranjan S. "Electronic nose based on nanomaterials: Issues, challenges, and prospects." ISRN Nanomaterials 2013 (2013).