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Under Guidance Of: PRESENTED BY:Dr SHAHANAZ AYUB 130433901(Associate Professor) (Electronics and Comm. Engg.)Deptt. Of Electronics and Comm. Engg. 3rd Year BIET JHANSI BIET JHANSI
E-NOSE
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Content Introduction
Definition and explanation
History
Need of an e-nose
Working principle
Sensor technology in e-nose
Performing an analysis with an e-nose
Applications
Conclusion
References
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Electronic noses are engineered to mimic the mammalian olfactory system.
Instrument designed to allow repeatable identifications and classifications of aroma
mixtures.
Determines the various characteristics properties of the odour while eliminating
operator fatigue.
Introduction- electronic nose(e-nose)
e-sensing
Refers to the capability of reproducing human senses using sensor arrays and
pattern recognition systems.
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Definition: electronic nose(e-nose)
Device intended to detect odour or flavors.
Can be seen as arrays of sensors able to generate
electrical signals in response to either simple or
complex volatile compounds present in the
gaseous sample.
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The first electronic noses were reported by Wilkens and Hatman in 1964
including Redox reactions.
The term electronic nose appeared around 1980s.
IN 1989, At conference of NATO chemo sensory information processing was
detected.
Finally first conference dedicated to e-nose was held in 1990.
History of e-nose
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The human sniffers are costly when compared to electronic nose.
Speedy, reliable new technology of the gas sensors are used in the electronic
nose
Detection of hazardous or poisonous gas is not possible with a human sniffer.
An e-nose also overcomes other problems associated with the human
olfactory system.
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Need of an e-nose
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Electronic noses include three major parts:
i. a sample delivery system
ii. a detection system
iii. a computing system
Working Principle
Sample delivery system
Enables the generation of the headspace (volatile compounds) of a
sample.
The system then injects this headspace into the detection system
of the e-nose.
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Detection System
Consist of a sensor set, is the "reactive" part of the instrument.
Absorption of volatile compounds on the sensor surface causes a physical change of the
sensor, they experience a change of electrical properties.
A specific response is recorded by the electronic interface transforming the signal into a
digital value.
Recorded data are then computed based on statistical models.
Computing System
Works to combine the responses of all the sensors.
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Metal oxide sensors
Adsorption of gas molecules provoke changes in conductivity.
This conductivity change is the measure of the amount of
volatile organic compounds adsorbed.
Conducting polymers
Conducting or conductive polymer gas sensors operate based on
changes in electrical resistance caused by adsorption of gases on
sensor surface.
Sensor technology in E-nose
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Quartz crystal microbalance
It’s a way of measuring mass per unit area by measuring the change
in frequency.
Can be stored in data base for future references.
Surface acoustic wave
It depends on modulation of surface acoustic wave to sense a
physical phenomenon
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Performing an analysis with an e-nose
As a first step, an e-nose needs to be trained with qualified samples so as to build a database
of reference.
Then the instrument can recognize new samples by comparing volatile compounds
fingerprint to those contained in its database.
Thus they can perform the analysis.
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Medical diagnosis and health monitoring
Environmental monitoring
Application in food industry
Detection of explosives
Space applications(NASA)
In research and development industries
In quality control laboratories
In process and production department
APPLICATIONS OF ELECTRONIC NOSE
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An “electronic nose” is a system originally created to copy the function of an animal nose.
Since the whole process is automatic, the cost of each measurement is very low.
Finally, the measurement cycle should be faster in order to increase throughput.
This sensor technology is still far from the sensitivity and selectivity of a real nose.
So it can’t totally replace the nose but can be used for different purposes with better
advancement in technology in future.
Conclusion
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[1] J.W. Gardner, P.N. Bartlett, "A brief history of electronic noses", Sensors and Actuators B, Vol.
18, 1994, pp. 211-220.
[2] Baltes, D. Lange and A. Koll, The electronic nose in Lilliput. IEEE Spectrum35 9 (1998), pp.
35-38.
[3] http://en.wikipedia.org/wiki/electronic nose
[4] I. Lundstrom, A. Spetz, F. Winquist, U. Ackelid, H. Sundgren, "Catalytic metals and field-effect
devices-a useful combination", Sensors and Actuators B: Chemical, Volume 1, Issues 1-6,
January 1990, Pages 15-20.
References