Indian Patents. 216811:"A PROCESS FOR MAKING A MOISTURE SENSOR OF PPMV LEVEL & A DEVICE FOR DETECTION OF MOISTURE MADE THEREFROM."

Title of Invention	"A PROCESS FOR MAKING A MOISTURE SENSOR OF PPMV LEVEL & A DEVICE FOR DETECTION OF MOISTURE MADE THEREFROM."
Abstract	A process for making a moisture sensor of ppmv level which comprises printing a tick film characterized in that the said thick film having interdigited electrodes of thickness atleast 30µm, on a porous ceramic substrate such as herein described, with thickness in the range of 0.1 mm-1,5mm by conventional thick film technique.

Full Text	The present invention relates to a process for making a moisture sensor of ppmv level & a device for detection of moisture made therefrom. Measurement of moisture in gases is very common in various types of applications. Now-a-days measurement of gas moisture is very widely used in various scientific and industrial applications and measurement of moisture in the ppmv level plays a vital role in the process. A few common examples are various kinds of chemical processes where specific range of gas moisture is necessary for the continuous chemical reactions to occur. References for which may be made to, (1) "Humidity sensors using anodized films with surface modifications". Kohtaio Nemoto, S.Chakravarty & Kazohiro Kara. Institute of Electronics, Information & communication Engineers, Japan. Technical report of I.E.I.E.C.E.C.P.M. 96-38 OME 96-25 (1996-06). Wherein Teflon or LiCl is deposited on porous A12O3 film by Ion beam deposition technique or by dipping into an aqueous solution of LiCl after deposition of thin A1203 film by RF sputtering. The sensitivity increases after deposition of Teflon or LiCl. (2) "Humidity sensitive electrical conduction of MgCr2O4TiO2 porous ceramic". J. Am. Ceram. Soc. 63 (5-6), 1980. Wherein the crystalline phase microstracture, semiconduction & humidity sensitive electrical conductance of MgCr2O4TiO2 ceramic has been studied. The humidity sensitive electrical conduction of MgCr2O4TiO2 porous ceramic is most promising for humidity sensing devices. The drawbacks of the above processes are (1) high manufacturing cost of the sensors, (2) delicate nature of the sensors, (3) regeneration of the sensor is not possible, (4) response time is high, (5) recovery time is high, (6) quasilinear in character, (7) sensitivity decreases at high moisture level & (8) big in size. The main objective of the present invention is to provide a process for making a novel moisture sensor in the ppmv ranges and a device for detection of moisture made therefrom. Another objective of the present invention is to provide a moisture sensor having very good sensitivity in the range of 10 - l000ppmv with a resolution of 5ppmv and response time less than 1 minute and recovery time of the order of 3 - 5secs. Accrodingly the present invention provides a process for making a moisture sensor of ppmv level which comprises printing a tick film characterized in that the said thick film having interdigited electrodes of thickness atleast 30µm, on a porous ceramic substrate such as herein described, with thickness in the range of 0.1 mm-1.5mm by conventional thick film technique. In an embodiment of the present invention the porous substrate may be such as pressed & sintered or tape casted product of materials, such as Alumina, Zirconia, Yttria stabilised Zirconia, Magnesia, Barium Titanate, Strontium Titanate. In an embodiment of the present invention the thickness of the interdigited electrode may be in range of 30µm - 50µm The present invention also provides a device for detection of moisture in the ppmv ranges, which comprises connecting the electrodes of the novel moisture sensor described above to a conventional monostable circuit driven by an astable circuit, the output of the said monostable circuit being converted to D.C. by conventional means and the resultant output being converted to an analogue or digital display. The steps of the process of the present invention are: 1. A ceramic substrate of thickness of 0.1mm to 1.5mm was taken. 2. Interdigited electrodes are printed on the surface of the ceramic substrate by thick film technique. 3. The device for detection of moisture comprises of connecting the electrodes of the novel moisture sensor described above to a conventional monostable circuit, which is driven by an astable circuit. The output of the monostable circuit is being connected to D.C. by conventional means & the resultant output of the said monostable circuit is being connected to an analogue or digital display. Moisture is always present both in medical as well as in commercial gases. It is obvious that some kind of instrument or gauge is necessary to measure the amount of moisture present in the above gases. The instrument used for the purpose is normally known as "Moisture Meter". A large number of different type of such meters or gauges working on different principles have been designed for over the years by various workers and many of them are being produced commercially. This may be broadly classified in two categories (a) Moisture meter with Hyper thin film alumina technology, (b) Tubular capacitive with Hygroscopic layer. Most of the above sensors are available for measuring moisture in the range of 0-1000 ppmv and sensitivity is not reliable due to quasilinear characteristic in the range 0-100 ppmv. Other limitations are that it has large recovery time and lifetime is also very short. The Moisture Meter with Hyper thin film alumina sensor is obviously more reliable and accurate and are most commonly used in process control applications. Among all the various types of sensors mentioned above, the present invention relates only to the Hyper thin film porous alumina both in terms of working principle and the range of measurement. Therefore a more detailed description of this type of sensor are presented here for better understanding of the importance of the present investigation. The most important component of the existing moisture meter, which is based on the change in capacitance, is the thin film capacitor (generally made up of thin film porous alumina). The amount of change in capacitance is calibrated with ppmv moisture level. The present invented moisture sensor works on the basic principle that when it absorbs moisture, it's dielectric constant changes, which changes capacity. The change in capacitance is measured in terms of change in voltage? The difference in voltage is calibrated for different moisture levels in the measurement of gas moisture. The sensor is capable of measuring moisture level from high to low concentration. The uniqueness of the present invention lies in the fact that the sensor has good sensitivity in the range of lOppmv to lOOOppmv with 5ppmv resolution, quick response time ( determined by the sensor. The width of the monostable pulse is directly proportional to sensor capacitance. The output obtained is given to an averaging circuit, comprising of resistance & capacitance which in turn is given to an analogue or digital display. As per known art, sensors for detection of moisture in ppmv ranges are all based on thin film technology that has certain drawbacks such as sensitivity not reliable, due to quasilinear charecteristics in the range of 10-100 ppmv, response & recovery time high, can not be regenarated & manufacturing cost is high. The novelity and inventive steps of the present invention lies in providing a sensor having porous ceramic substrate with thick film in interdigited electrodes. The advantages are 1. High sensitivity 3mv/5ppmv. 2. Fast response ( 3. Temperature stability over full ranges (50 - 1000 ppmv). 4. Not sensitive to electrical noise. 5. Practically no drift over time. 6. Low cost compared to conventional exported sensors available in the market. 7. The sensor can be regenerated by direct cleaning with organic solvents like alcohol, acetone etc. The following examples illustrate the invention in the manner in which it may be carried out in practice. However this should not limit the scope of the present invention. Example -1 A porous Alumina substrate of thickness of 1.2mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example - 2 A porous Zirconia substrate of thickness of 1.5mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example - 3 A porous Yttria stabilised Zirconia substrate of thickness of 1.4mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example - 4 A porous Magnesia substrate of thickness of 1.5mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example - 5 A porous Barium Titanate substrate of thickness of 1.2mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example - 6 A porous Strontium Titanate substrate of thickness of 1.5mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example - 7 A porous tape casted Alumina substrate of thickness of O.lmm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example - 8 A porous tape casted Zirconia substrate of thickness of 0.15m is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example - 9 A porous tape casted Yttria stabilised Zirconia substrate of thickness of 0.3mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example -10 A porous tape casted Magnesia substrate of thickness of 0.3mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example-11 A porous tape casted Barium Titanate substrate of thickness of 0.2 mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. Example -12 A porous tape casted Strontium Titanate substrate of thickness of 0.1 mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display. We Claim: 1 .A process for making a moisture sensor of ppmv level which comprises printing a tick film characterized in that the said thick film having interdigited electrodes of thickness atleast 30µm, on a porous ceramic substrate such as herein described, with thickness in the range of 0.1 mm-1.5mm by conventional thick film technique. 2. A process as claimed in claim-1, wherein the porous substrate is pressed & sintered or tape-casted product of materials such as: A12O3, ZrO2, YSZ, MgO, BaTiO3 SrTiO3. 3. A process as claimed in claims 1&2 wherein the thickness of the electrodes are in the range of 30µm -50µm. 4.A device for detection of moisture sensor in the ppmv level, which comprises connecting the electrodes of the moisture sensor as claimed in claims 1 to a conventional monostable circuit driven by an astable circuit, the-output of the said monostable circuit being converted to D.C. and the resultant output being converted to an analogue or digital display. 5. A process for making a moisture sensor of ppmv level substantially as herein described with reference to the examples.

Full Text

The present invention relates to a process for making a moisture sensor of ppmv level & a device for detection of moisture made therefrom.
Measurement of moisture in gases is very common in various types of applications. Now-a-days measurement of gas moisture is very widely used in various scientific and industrial applications and measurement of moisture in the ppmv level plays a vital role in the process. A few common examples are various kinds of chemical processes where specific range of gas moisture is necessary for the continuous chemical reactions to occur.
References for which may be made to, (1) "Humidity sensors using anodized films with surface modifications". Kohtaio Nemoto, S.Chakravarty & Kazohiro Kara. Institute of Electronics, Information & communication Engineers, Japan. Technical report of I.E.I.E.C.E.C.P.M. 96-38 OME 96-25 (1996-06).
Wherein Teflon or LiCl is deposited on porous A12O3 film by Ion beam deposition technique or by dipping into an aqueous solution of LiCl after deposition of thin A1203 film by RF sputtering. The sensitivity increases after deposition of Teflon or LiCl.

(2) "Humidity sensitive electrical conduction of MgCr2O4TiO2 porous ceramic". J. Am. Ceram. Soc. 63 (5-6), 1980.

Wherein the crystalline phase microstracture, semiconduction & humidity sensitive electrical conductance of MgCr2O4TiO2 ceramic has been studied. The humidity sensitive electrical conduction of MgCr2O4TiO2 porous ceramic is most promising for humidity sensing devices. The drawbacks of the above processes are (1) high manufacturing cost of the sensors, (2) delicate nature of the sensors, (3) regeneration of the sensor is not possible, (4) response time is high, (5) recovery time is high, (6) quasilinear in character, (7) sensitivity decreases at high moisture level & (8) big in size.
The main objective of the present invention is to provide a process for making a novel moisture sensor in the ppmv ranges and a device for detection of moisture made therefrom.
Another objective of the present invention is to provide a moisture sensor having very good sensitivity in the range of 10 - l000ppmv with a resolution of 5ppmv and response time less than 1 minute and recovery time of the order of 3 - 5secs.

Accrodingly the present invention provides a process for making a moisture sensor of ppmv level which comprises printing a tick film characterized in that the said thick film having interdigited electrodes of thickness atleast 30µm, on a porous ceramic substrate such as herein described, with thickness in the range of 0.1 mm-1.5mm by conventional thick film technique.
In an embodiment of the present invention the porous substrate may be such as pressed & sintered or tape casted product of materials, such as Alumina, Zirconia, Yttria stabilised Zirconia, Magnesia, Barium Titanate, Strontium Titanate.
In an embodiment of the present invention the thickness of the interdigited electrode may be in range of 30µm - 50µm
The present invention also provides a device for detection of moisture in the ppmv ranges, which comprises connecting the electrodes of the novel moisture sensor described above to a conventional monostable circuit driven by an astable circuit, the output of the said monostable circuit being converted to D.C. by conventional means and the resultant output being converted to an analogue or digital display.

The steps of the process of the present invention are:
1. A ceramic substrate of thickness of 0.1mm to 1.5mm was taken.

2. Interdigited electrodes are printed on the surface of the ceramic substrate

by thick film technique.
3. The device for detection of moisture comprises of connecting the electrodes of the novel moisture sensor described above to a conventional monostable circuit, which is driven by an astable circuit. The output of the monostable circuit is being connected to D.C. by conventional means & the resultant output of the said monostable circuit is being connected to an analogue or digital display.
Moisture is always present both in medical as well as in commercial gases. It is obvious that some kind of instrument or gauge is necessary to measure the amount of moisture present in the above gases. The instrument used for

the purpose is normally known as "Moisture Meter". A large number of different type of such meters or gauges working on different principles have been designed for over the years by various workers and many of them are being produced commercially. This may be broadly classified in two categories (a) Moisture meter with Hyper thin film alumina technology, (b) Tubular capacitive with Hygroscopic layer.
Most of the above sensors are available for measuring moisture in the range of 0-1000 ppmv and sensitivity is not reliable due to quasilinear characteristic in the range 0-100 ppmv. Other limitations are that it has large recovery time and lifetime is also very short.
The Moisture Meter with Hyper thin film alumina sensor is obviously more reliable and accurate and are most commonly used in process control applications. Among all the various types of sensors mentioned above, the present invention relates only to the Hyper thin film porous alumina both in terms of working principle and the range of measurement. Therefore a more detailed description of this type of sensor are presented here for better understanding of the importance of the present investigation.

The most important component of the existing moisture meter, which is based on the change in capacitance, is the thin film capacitor (generally made up of thin film porous alumina). The amount of change in capacitance is calibrated with ppmv moisture level.
The present invented moisture sensor works on the basic principle that when it absorbs moisture, it's dielectric constant changes, which changes capacity.

The change in capacitance is measured in terms of change in voltage? The difference in voltage is calibrated for different moisture levels in the measurement of gas moisture. The sensor is capable of measuring moisture level from high to low concentration. The uniqueness of the present invention lies in the fact that the sensor has good sensitivity in the range of lOppmv to lOOOppmv with 5ppmv resolution, quick response time (
determined by the sensor. The width of the monostable pulse is directly
proportional to sensor capacitance. The output obtained is given to an
averaging circuit, comprising of resistance & capacitance which in turn is
given to an analogue or digital display.
As per known art, sensors for detection of moisture in ppmv ranges are all
based on thin film technology that has certain drawbacks such as sensitivity
not reliable, due to quasilinear charecteristics in the range of 10-100 ppmv,
response & recovery time high, can not be regenarated & manufacturing cost
is high.
The novelity and inventive steps of the present invention lies in providing a
sensor having porous ceramic substrate with thick film in interdigited
electrodes.
The advantages are
1. High sensitivity 3mv/5ppmv.
2. Fast response ( 3. Temperature stability over full ranges (50 - 1000 ppmv).
4. Not sensitive to electrical noise.
5. Practically no drift over time.

6. Low cost compared to conventional exported sensors available in the
market.
7. The sensor can be regenerated by direct cleaning with organic solvents
like alcohol, acetone etc.
The following examples illustrate the invention in the manner in which it may be carried out in practice. However this should not limit the scope of the present invention.
Example -1
A porous Alumina substrate of thickness of 1.2mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.

Example - 2
A porous Zirconia substrate of thickness of 1.5mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.
Example - 3
A porous Yttria stabilised Zirconia substrate of thickness of 1.4mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.

Example - 4
A porous Magnesia substrate of thickness of 1.5mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.
Example - 5
A porous Barium Titanate substrate of thickness of 1.2mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.

Example - 6
A porous Strontium Titanate substrate of thickness of 1.5mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.
Example - 7
A porous tape casted Alumina substrate of thickness of O.lmm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.

Example - 8
A porous tape casted Zirconia substrate of thickness of 0.15m is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.
Example - 9
A porous tape casted Yttria stabilised Zirconia substrate of thickness of 0.3mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.

Example -10
A porous tape casted Magnesia substrate of thickness of 0.3mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.
Example-11
A porous tape casted Barium Titanate substrate of thickness of 0.2 mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.

Example -12
A porous tape casted Strontium Titanate substrate of thickness of 0.1 mm is taken. Interdigited electrodes are printed on the surface of the ceramic substrate by conventional thick film technique. The electrodes on the ceramic substrates are connected to a timing monostable circuit. Monostable circuit is driven by an astable circuit, the output of the said monostable circuit being converted to DC by conventional means and the resultant output is connected to an analogue or digital display.

We Claim:
1 .A process for making a moisture sensor of ppmv level which comprises printing a tick film characterized in that the said thick film having interdigited electrodes of thickness atleast 30µm, on a porous ceramic substrate such as herein described, with thickness in the range of 0.1 mm-1.5mm by conventional thick film technique.
2. A process as claimed in claim-1, wherein the porous substrate is pressed & sintered
or tape-casted product of materials such as: A12O3, ZrO2, YSZ, MgO, BaTiO3 SrTiO3.
3. A process as claimed in claims 1&2 wherein the thickness of the electrodes are in
the range of 30µm -50µm.
4.A device for detection of moisture sensor in the ppmv level, which comprises connecting the electrodes of the moisture sensor as claimed in claims 1 to a conventional monostable circuit driven by an astable circuit, the-output of the said monostable circuit being converted to D.C. and the resultant output being converted to an analogue or digital display.
5. A process for making a moisture sensor of ppmv level substantially as herein described with reference to the examples.

Documents:

246-del-2000-abstract.pdf

246-del-2000-claims.pdf

246-del-2000-correspondence-others.pdf

246-del-2000-correspondence-po.pdf

246-del-2000-description (complete).pdf

246-del-2000-form-1.pdf

246-del-2000-form-19.pdf

246-del-2000-form-2.pdf

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Patent Number

216811

Indian Patent Application Number

246/DEL/2000

PG Journal Number

13/2008

Publication Date

31-Mar-2008

Grant Date

19-Mar-2008

Date of Filing

16-Mar-2000

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	MANJUSREE SAHA	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA
2	SIBDAS BANDHOPADHYAY	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA
3	DEBDAS CHATTOPADHYAY	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA
4	SANTANU BASU	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA
5	KALYAN KUMAR MISTRY	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA
6	KAMALENDU SENGUPTA,	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA

PCT International Classification Number

G01R 27/08

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA