18-07-2011, 11:09 AM
[attachment=14549]
INTRODUCTION
The electronics field is developing at a fast rate. Each
day the industry is coming with new technology and
products. The electronic components play a major role in
all fields of life. The scientists had started to mimic the
biological world. The development of artificial neural
network (ANN), in which the nervous system is
electronically implemented is one among them.
The scientists realized the importance of the
detection and identification of odor in many fields. In
human body it is achieved with the help of one of the
sense organ, the nose. So scientists realized the need of
imitating the human nose. The concept of the electronic
nose appeared for the first time in a nature paper by
Persuade and Dodd (1982). The authors suggested and
demonstrated with a few examples that gas sensor array
responses could be analyzed with artificial neural
networks thereby increasing sensitivity and precision in
analysis significantly. This first publication was followed
by several methodological papers evaluating different
sensor types and combinations.
The scientists saw the last advances in the electronic
means of seeing and hearing. Witnessing this fast
advances they scent a marker for systems mimicking the
human nose. The harnessing of electronics to measure
odor is greatly desired. Human panels backed by gas
chromatography (GC)/ mass spectroscopy (MS) are helpful
Electronic Nose
in quantifying smells. The human panels are subject to
fatigue and inconsistencies. While classical gas
chromatography (GC)/ mass spectrograph (MS) technique
separate quantify and identify individual volatile
chemicals, they cannot tell us if the components have an
odour. Also they are very slow. So it is important that
faster methods must give way to speedier procedure using
an electronic nose composed of gas sensory. The E-nose
was developed not to replace traditional GC/MS and
sensory techniques. The E-nose was sensitive and as
discriminating as the human nose, and it also correlates
extremely with GC/MS data. The electronic nose allows to
transfer expert know ledged from highly trained sensory
panels and very sophisticated R&D analytical techniques
to the production floor for the control of quality. Although
the human nose is very sensitive, it is highly subjective.
The E – nose offers objectivity and reproducibility.
The electronic nose technology goes several steps
ahead of the conventional gas sensors. The electronics
nose system detects and sensing devices with pattern
recognition sub system. The electronic nose won quickly
considerable interest in food analysis for rapid and reliable
quality classification in manufacturing testing. Later, the
electronic noses have also been applied to classification of
micro organisms and bio-reactor monitoring. Even though
the electronic nose resembles its biological counter part
nose too closely the label “electronic nose” or “E-nose” has
been widely accepted around the world.
Electronic Nose
THE BIOLOGICAL NOSE
To attempt to mimic the human apparatus,
researchers have identified distinct steps that characterize
the way humans smell. It all begins with sniffing, which
moves air samples that contain molecules of odors past
curved bony structures called turbinate. The turbinate
create turbulent airflow patterns that carry the mixture of
volatile compounds to that thin mucus coating of the
nose’s olfactory epithelium, where ends if the nerve cells
that sense odorants.
The volatile organic compounds (VOCs) basic to
odors reach the olfactory epithelium in gaseous form or
else as a coating on the particles that fill the air we
breathe. Particles reach the olfactory epithelium not only
from the nostrils but also from the mouth when food is
chewed.
As VOCs and particles carrying VOCs pass over the
mucus membrane lining the nose, they are trapped by the
mucus and diffuse through to the next layer, namely, the
epithelium, where the sensory cells lie in wait. The cells
are covered in multiple cilia- hair like structures with
receptors located on the cells outer membranes. Olfactory
cells are specialized neurons that are replicated
approximately every 30 days.
INTRODUCTION
The electronics field is developing at a fast rate. Each
day the industry is coming with new technology and
products. The electronic components play a major role in
all fields of life. The scientists had started to mimic the
biological world. The development of artificial neural
network (ANN), in which the nervous system is
electronically implemented is one among them.
The scientists realized the importance of the
detection and identification of odor in many fields. In
human body it is achieved with the help of one of the
sense organ, the nose. So scientists realized the need of
imitating the human nose. The concept of the electronic
nose appeared for the first time in a nature paper by
Persuade and Dodd (1982). The authors suggested and
demonstrated with a few examples that gas sensor array
responses could be analyzed with artificial neural
networks thereby increasing sensitivity and precision in
analysis significantly. This first publication was followed
by several methodological papers evaluating different
sensor types and combinations.
The scientists saw the last advances in the electronic
means of seeing and hearing. Witnessing this fast
advances they scent a marker for systems mimicking the
human nose. The harnessing of electronics to measure
odor is greatly desired. Human panels backed by gas
chromatography (GC)/ mass spectroscopy (MS) are helpful
Electronic Nose
in quantifying smells. The human panels are subject to
fatigue and inconsistencies. While classical gas
chromatography (GC)/ mass spectrograph (MS) technique
separate quantify and identify individual volatile
chemicals, they cannot tell us if the components have an
odour. Also they are very slow. So it is important that
faster methods must give way to speedier procedure using
an electronic nose composed of gas sensory. The E-nose
was developed not to replace traditional GC/MS and
sensory techniques. The E-nose was sensitive and as
discriminating as the human nose, and it also correlates
extremely with GC/MS data. The electronic nose allows to
transfer expert know ledged from highly trained sensory
panels and very sophisticated R&D analytical techniques
to the production floor for the control of quality. Although
the human nose is very sensitive, it is highly subjective.
The E – nose offers objectivity and reproducibility.
The electronic nose technology goes several steps
ahead of the conventional gas sensors. The electronics
nose system detects and sensing devices with pattern
recognition sub system. The electronic nose won quickly
considerable interest in food analysis for rapid and reliable
quality classification in manufacturing testing. Later, the
electronic noses have also been applied to classification of
micro organisms and bio-reactor monitoring. Even though
the electronic nose resembles its biological counter part
nose too closely the label “electronic nose” or “E-nose” has
been widely accepted around the world.
Electronic Nose
THE BIOLOGICAL NOSE
To attempt to mimic the human apparatus,
researchers have identified distinct steps that characterize
the way humans smell. It all begins with sniffing, which
moves air samples that contain molecules of odors past
curved bony structures called turbinate. The turbinate
create turbulent airflow patterns that carry the mixture of
volatile compounds to that thin mucus coating of the
nose’s olfactory epithelium, where ends if the nerve cells
that sense odorants.
The volatile organic compounds (VOCs) basic to
odors reach the olfactory epithelium in gaseous form or
else as a coating on the particles that fill the air we
breathe. Particles reach the olfactory epithelium not only
from the nostrils but also from the mouth when food is
chewed.
As VOCs and particles carrying VOCs pass over the
mucus membrane lining the nose, they are trapped by the
mucus and diffuse through to the next layer, namely, the
epithelium, where the sensory cells lie in wait. The cells
are covered in multiple cilia- hair like structures with
receptors located on the cells outer membranes. Olfactory
cells are specialized neurons that are replicated
approximately every 30 days.
