An Empirical Concept Of E-noses

AN EMPIRICAL CONCEPT OF E-NOSES. Alluri Institue of Management Sciences. Electronic or artificial noses are being developed as processes for the automated detection and classification of odors, vapors, and gases. An electronic nose is generally composed of a chemical sensing system e. , sensor array or spectrometer and a pattern recognition system e.

, artificial neural network. We are developing electronic noses for the automated identification of volatile chemicals for environmental and medicinal applications. In this paper, we briefly describe an electronic nose, display some conclusions from a prototype electronic nose, and discuss applications of electronic noses within the environmental, medical, and food industries. An electronic nose e-nose is a device that identifies the critical components of an odor and analyzes its chemical makeup to identify it. An electronic nose consists of a mechanism for chemical detection, for example an array of electronic sensors, and a mechanism for pattern recognition, for example a neural network.

Electronic noses have been around for multiple years but have typically been large and expensive. Current studies is focused on creating the devices smaller, fewer expensive, and more sensitive. The smallest version, a nose-on-a-chip is a lone computer chip containing most the sensors and the processing components. An odor is composed of molecules, each of which has a critical volume and shape. Each of these molecules has a correspondingly sized and shaped receptor within the person nose.

When a critical receptor receives a molecule, it sends a signal to brain and the brain identifies the smell associated with that critical molecule. Electronic noses based on the biological model work in a similar manner, albeit substituting sensors for the receptors, and transmitting the signal to a program for processing, rather than to brain. Electronic noses are one example of a growing studies region called biomimetics, or biomimicry, which involves human-made applications patterned on natural phenomena. Electronic noses were originally used for quality manage applications within the food, beverage and cosmetics industries. Current applications with detection of odors critical to diseases for medicinal diagnosis, and detection of pollutants and gas leaks for environmental protection.

Keywords: enose, artificial nose, network, environment, sensing. The 3 primary components of an electronic nose are the sensing system and the automated pattern recognition system. The sensing system should be an array of multiple different sensing elements e. , chemical sensors, where each element measures an alternate property regarding the sensed chemical, or it should be a lone sensing device e. , spectrometer that produces an array of measurements for each chemical, or it should be a combination.

Each chemical vapor presented to sensor array produces a signature or pattern characteristic regarding the vapor. By presenting many different chemicals to sensor array, a database of signatures is built up. This database of labeled signatures is used to train the pattern recognition system. The goal of this training process is to configure the recognition system to make unique classifications of each chemical such that an automated identification should be implemented. The quantity and complexity regarding the data collected by sensors array can make conventional chemical analysis of data in an automated fashion difficult.

One approach to chemical vapor identification is to build an array of sensors, where each sensor within the array is drafted to respond to a critical chemical. With this approach, the many unique sensors should be at fewest as good as the many chemicals being monitored. It is most expensive and difficult to build highly selective chemical sensors. Artificial neural networks ANNs, which have been used to analyze complex data and to recognize patterns, are showing promising conclusions in chemical vapor recognition. When an ANN is combined with a sensor array, the many detectable chemicals is generally greater than the many sensors [1].

Also, fewer selective sensors which are generally fewer expensive should be used with this approach. Once the ANN is trained for chemical vapor recognition, procedure consists of propagating the sensor data through the network. Since this is basically a series of vector-matrix multiplications, unknown chemicals should be rapidly identified within the field. Electronic noses that incorporate ANNs have been demonstrated in different applications. Little of these applications shall be discussed later within the paper.

Many ANN configurations and training algorithms have been used to build electronic noses within return propagation-trained, feed-forward networks; fuzzy ARTmaps; Kohonens self-organizing maps SOMs? learning vector quantizers LVQs? Hamming networks; Boltzmann machines; and Hopfield networks. Figure two illustrates the simple schematic of an electronic nose. Figure 1: Schematic diagram of an electronic nose. Electronic Noses for Environmental Monitoring. Enormous amounts of hazardous waste nuclear, chemical, and mixed wastes were generated by higher than 40 years of weapons production within the USA Department of Energys weapons complex.

The Pacific Northwest Local Science department is exploring the technologies compulsory to perform environmental restoration and waste management in a reasonably priced manner. This effort includes the development of portable, inexpensive processes capable of real-time identification of contaminants within the field. Electronic noses fit this category. Environmental applications of electronic noses with analysis of fuel mixtures, detection of oil leaks, testing ground h2o for odors, and identification of household odors. Potential applications with identification of toxic wastes, space quality monitoring, and monitoring factory emissions.

Electronic Noses for Medicine. Because the sense of smell is an important sense to physician, an electronic nose has applicability like a diagnostic tool. An electronic nose can examine odors from the body e. , breath, wounds, body fluids, etc. and identify likely problems.

Odors within the breath should be indicative of gastrointestinal problems, sinus problems, infections, diabetes, and liver problems. Infected wounds and tissues emit distinctive odors that should be detected by an electronic nose. Odors coming from body fluids can indicate liver and bladder problems. Currently, an electronic nose for examining wound infections is being tested at Southern Manchester University Hospital. A more futuristic application of electronic noses was recently proposed for telesurgery.

While the inclusion of visual, aural, and tactile senses into telepresent processes is widespread, the sense of smell was largely ignored. An electronic nose shall potentially be a key component in an olfactory input to telepresent virtual reality processes within telesurgery. The electronic nose should identify odors within the remote surgical environment. These identified odors should then be electronically transmitted to another location where an odor generation system should recreate them. Electronic Noses for the Food Industry.

Currently, the biggest market for electronic noses is the food industry. Applications of electronic noses within the food business with quality assessment in food production, inspection of food quality by odor, manage of food baking processes, inspection of fish, monitoring the fermentation process, checking rancidity of mayonnaise, verifying if orange sip is natural, monitoring food and beverage odors, grading whiskey, inspection of beverage containers, checking glass wrap for containment of onion odor, and automated taste manage to name a few. In some instances electronic noses should be used to augment or replace panels of person experts. In other cases, electronic noses should be used to reduce the no. of analytical chemistry that is performed in food production mostly when qualitative conclusions shall do.

Electronic nose for evaluation of tea flavour drafted by cdac kolkata Electronic Nose is a smart instrument that is drafted to detect and discriminate between complex odours creating use of an array of sensors. The array of sensors consists of a many broadly tuned non-specific sensors that are treated with an alternate categories of odour-sensitive biological or chemical materials. An odour stimulus generates a characteristic fingerprint from this array of sensors. Patterns or fingerprints from known odours are used to construct a database and train a pattern recognition system such that unknown odours can subsequently be classified and or or identified. An electronic nose system primarily consists of 4 functional blocks, viz.

, Odour Handling and Delivery System, Sensors and Interface Electronics, Signal Processing and Intelligent Pattern Analysis and Recognition. The array of sensors is exposed to volatile odour vapour through suitable odour handling and delivery system that ensures constant exposure rate to each regarding the sensors. The response signals of sensor array are conditioned and processed through suitable circuitry and fed to an intelligent pattern recognition engine for classification, analysis and declaration. The highest many complicated components of electronic olfaction process are odour capture and associated sensor technology. Any sensor that responds reversibly to chemicals in gas or vapour phase, has the potential to be participate in an array of sensor in an electronic nose.

For black manufactured tea, an array of Metal Oxide Semiconductor MoS sensors have been used for assessment of volatiles. E-Nose for Assessment of Optimum. As soon as tea leave cells are ruptured within the CTC or Rolling process, the process of fermentation starts. Limiting the reactions and chemical transformations during fermentation process to an optimum limit is vital for producing superior quality tea. It is, thus, critical that the leaf be allowed to ferment only up to desired limit such that the complex series of chemical changes within the leaf are accomplished optimally.

Conventionally, length of fermentation is subjectively estimated by person senses of smell and vision. Person experts can sense conversion of grassy smell to floral smell of inprocess leaves subsequent to fermentation. But, such odour emanation travels through cycles of so called First Nose and 2nd Nose etc. A colorimetric approach also shall also be used at times where fermentation completion time is determined based on colour. FOR EVALUATION OF TEA FLAVOUR.

A specially drafted Electronic Nose was successfully used to monitor volatile emission pattern in fermentation process over passage of time. Through prolonged experimentation with different clones, fermentation processes and climatic variations, it was established that smell changes during the process should be reliably detected repeatedly by Electronic Nose. Even the smell peaks during so called First Nose and 2nd Nose shall also be clearly detected with this new smart instrument. E-Nose for Finished Tea Classification:. Flavour and Aroma are important quality attributes of finished tea.

Person experts called Tea Tasters conventionally determine tea quality. Tea tasters usually assign scores to samples of tea below evaluation in a scale of two to 10 depending on the flavour, aroma and appearance regarding the sample. Electronic Nose is an one of a kind tool that is capable of sensing the volatile compounds of the. tea sample and reliably predicts Tea Taster like scores with an above degree of accuracy. Neural Network based Soft Computing Techniques are used to tune near accurate co-relation smell print of multi-sensor array with that of Tea Tasters' scores.

The software framework was drafted with adequate flexibility and openness such that tea planters themselves shall train the system with their own system of scoring such that the instrument will, then on, reliably predict such smell print scores. In addition, encouraging conclusions have also been obtained during the preliminary experimentations with Withering Process to expect Electronic Nose also to be a useful instrument for determining the optimum Withering time. A user-friendly interactive software was carefully drafted which has got features like programmable sequence control, dynamic fermentation profile display, data logging, alarm annunciation, data archival, etc. The Tea Business shall adopt such easy-to-operate though hi-tech smart instrument. Nanotechnology electronic noses-Next Gen E Noses.

Nanowerk Spotlight The concept of e-noses - electronic devices which mimic the olfactory processes of mammals and insects - is very intriguing to researchers involved in building better, cheaper and smaller sensor devices. A better understanding regarding the reception, signal transduction and odor recognition mechanisms for mammals, combined with achievements in fabric science, microelectronics and computer science has led to significant advances in this area. Nevertheless, the olfactory system of even the simplest insects is so complex that it is still impossible to reproduce it at the current position of technology. For example, the biological receptors are regularly replaced during the life of mammals in a very reliable method such that the receptor array does not want to be recalibrated. The performance of existing artificial electronic nose devices is many more dependent on the sensor's aging and, especially, the sensor's replacement and frequently want a recalibration to account for change.

Moreover, current electronic nose devices based on metal oxide semiconductors or conducting polymers that specifically identify gaseous odorants are typically large and expensive and thus not adequate for use in micro- or nano-arrays that should mimic the performance regarding the natural olfactory system. Nanotechnology is seen like a key in advancing e-nose devices to a position that shall match the olfactory processes developed by nature. Nanowire chemiresistors are seen as critical elements within the future miniaturization of e-noses. It is now also believed that lone crystal nanowires are most stable sensing elements what shall result in extending of life-time of sensors and that is why the recalibration cycle. Final year we reported on a studies effort Towards The Nanoscopic Electronic Nose.

Scientists involved in this effort now report a second-generation, distant more advanced e-nose system based on metal oxide nanowires. Despite encouraging demonstrations of an array of lone metal oxide nanowires, there still exists a technological gap between the science department demonstrations and a practical e-nose micro device suitable for up-to-date large-scale microfabrication and capable of operating in real-world environments Dr. Andrei Kolmakov explains to Nanowerk. Hence, our aim was to bridge this gap and demonstrate the excellent performance of a practical device created by combining 'bottom-up' fabricated SnO2 nanowires or nanobelts as sensing elements with a 'top-down' cutting edge designs regarding the state-of-the-art multi electrode KAMINA platform. Kolmakov, an assistant professor within the physics department at Southern Illinois University at Carbondale points out that this work is an example of successful truly worldwide collaboration between his group, Dr.

Victor Sysoev electronic noses specialist, Saratov State University, Russia and team of Dr. Joachim Goschnick developers regarding the commercial KAMINA e-nose system Forschungszentrum Karlsruhe, Germany. Basically, we took a very robust and successful KAMINA KArlsruhe Micro NAse; pdf download German or English datasheet, 128 KB electronic nose platform and instead of creating use of the traditional thin-film sensing element we implemented completely new morphology regarding the sensing layer, which in our case, is composed out regarding the layer of tin oxide nanowires says Kolmakov. Artistic comparison regarding the primary steps in functioning regarding the person left and artificial olfactory processes right. However, the e-nose based on nanowire mats is yet too primitive even in comparison to simplest of insects' olfaction.

Kolmakov, Southern Illinois University at Carbondale He explains that their device shows a sure degree of analogy with neurons: The randomly distributed nanowires contact each other and shape multiple percolation paths for signal transmission. The resistance of these percolating nanowires is a very sensitive function regarding the gas environment. Due to a stochastic difference regarding the percolating pattern between every 3 electrodes the space between each couple of electrodes serves like a separate sensor, the sensor array of multi-electrodes produces an alternate response pattern to differing analytes. Similar to our brain, the processor attached to e-nose conditions and analyzes the electrical signals coming from the sensor array and, creating use of pattern recognition techniques, produces the image regarding the 'odor'. This is a distant more advanced system than what Kolmakov and his collaborators demonstrated final year.

In this new device, the scientists decided to benefit from the stochastic nature regarding the percolating nanowire network. From the spot of view regarding the sensitivity and selectivity toward the gases we probed, this e-nose was showing the excellent conclusions compared to existing macroscopic counterparts says Kolmakov. With this new methodology we are getting intriguing results, which we are still analyzing. For example, we learned that sequential to discriminate between different analytes, our artificial nose does not want any heat gradient that is a simple principle of procedure regarding the traditional KAMINA e-nose and we can with no problems play with just a density regarding the percolating nanowires at the substrate to substantially change the gas-recognition properties regarding the array. In addition to that, there exists plenty of other functionalization possibilities for our sensing elements to tune the sensor properties in a rational and easy way.

That is howcome we think about mimicking the net of neurons as one regarding the highest many promising paths within the development of next generation electronic noses. Kolmakov and his grup are currently testing the strategy to eliminate any heaters within the device, thus creating it likely to operate a microchip at room temperature. This drastically reduces the power requirements This work shows that gradient micro arrays with sensing elements based on metal oxide nanowire mats of different density appear to be a novel technologically simple and powerful approach for fabrication of robust, cost-effective, sensitive, and highly selective nose-like gas analytical devices. This kind of nanosensor device opens an unique direction within the development of extremely non-pricey a little dollars, since there is no need for any expensive nanomanipulation and sophisticated top-down protocols but yet ultra mini and powerful electronic detectors which are can recognize complex chemicals against a disturbing background of other gases and report if any dangerous thresholds have been approached. There is a huge need for these sensors within the modern urban environment, in environmental applications, and for security.

Kolmakov points out that such 'intelligent' sensor processes should be installed almost everywhere cell-phones, car dashboards and exhaust systems, manufacturing plants, oil platforms, even in soldiers' helmets etc. Moreover, the system is sensitive to ionizing radiation and should be a monitor for x-rays and nuclear contaminations. New emerging technologies are continually providing means of improving e-noses and EAD capabilities through interfaces and combinations with classical analytical processes for rapid discrimination of lone chemical species within aroma mixtures. E-nose instruments are being developed that combine EAD sensors in tandem with analytical detectors for example with fast gas chromatography FGC. More complicated technologies for example optical gas sensor processes also shall improve on traditional e-nose sensor arrays by providing analytical data of mix constituents.

These technologies shall have the capability of producing recognizable high resolution visual images of critical vapor mixtures containing many different chemical species, but also quantifying concentrations and identifying all compounds present within the gas mixture. Similar capabilities for identifying components of solid and liquid mixtures should be likely with devices called electronic tongues. Multiple recent reviews give summaries of electronic tongue technologies and discuss potential applications for food analyses. The potential for future developments of innovative e-nose applications is enormous as researchers in many fields of scientific investigation and non-residential development grow to more aware regarding the capabilities regarding the electronic nose. The current trend is toward the development of electronic noses for critical purposes or a fairly narrow section of applications.

This strategy increases e-nose efficiency by minimizing the many sensors wanted for discriminations, reducing instrument costs, and allowing for greater portability through miniaturization. New potential discoveries in this relatively new sector of sensor cutting edge designs shall continue to expand as new products, machines, and non-residential processes are developed. These discoveries shall lead to recognition of new ways to exploit the electronic nose to solve many new problems for the benefit of mankind. Electronic Nose for evaluation of tea PDF- November 2005. Electronic Noses? researchers published their conclusions within the October 10, 2007 online edition of Nano Letters A Gradient Micro array Electronic Nose Based on Percolating SnO2 Nanowire Sensing Elements.

This cardboard was presented at Neural Network Applications Studies Workshop within the IEEE Northcon or Technical Applications Conference TAC'95 in Portland, Oregon, USA on 12 October 1995. Electronic Noses Sniff Success Chang, J. This cardboard appears in: Spectrum, IEEE Publication Date: March 2008 Volume: 45, Issue: 4 On page s? 50-56. Intelligent electronic nose system for basal stem rot sickness detectionVolume 66 Issue 3 Shall 2009 - Elsevier Science Publishers B. Amsterdam, The Netherlands, The Netherlands ACM Journal.