ফিরে দেখা

Sooo? Today is already Wednesday. But I atleast went to IISc on Saturday. Read mostly from the book Sensors : Comprehensive update vol - 2 part - II. I also got a good review paper by Janata(Courtsey - Panto). I think, in the report about gas sensors, I should write about different detection principles of sensors with case studies i.e. citing different papers in that field. But then categorization becomes difficult. According to the book Physics, Chemistry and Technology of Solid State Gas Sensor Devices there are 6 categories :

1. Solid state semiconductor sensors
2. Photonic and photoaccoustic sensors
3. Fiber optic sensors
4. Piezoelectric quartz crystal micobalance sensor
5. Surface accoustic wave sensors
6. Pyroelectric and thermal sensors

According to Janatas review paper, chemical (not gas) sensors are categorized like this:

1. Thermal sensors
2. Mass sensors
3. Electrochemical sensors
4. Potentiometric sensors
5. Amperometric sensors
6. Conductometric sensors
7. Optical sensors
   

According to Sensors update "The different types of chemical sensors may be classified according to the different sensor properties used for particle detection." They are (as listed in the book)

1. Liquid state electrolyte sensors
2. Solid-state electrolyte sensors
3. Electronic conductance and capacitance sensors
4. Field effect sensors
5. Calorimetric sensors
6. Optochemical and photometric sensors
7. Mass-sensitive sensors
   

If we are already confused, lets relate things. I think Surface Accoustic Wave(SAW) sensor is a mass-sensitive sensor. (There is also something called BAW, B for bulk). Moseleys book talks about Pellistor(?) or catalytic combustible sensor which should be a thermal/calorimetric/ Pyroelectric sensor. Galvanic sensor will probably be a Liquid/solid-state electrolyte sensor. SnO2 sensor is definitely going to be in Electronic conductance sensors. But I have a strong feeling that SAW has something to do with Piezoelectric quartz crystal micobalance sensors. Now I should read about all these different sensing principles.
One of the achievements in last three days is I learnt how to use bibtex.
Right now reading an article about "why-mass" in Scientific American. It talks about Higgs field(Dont Ask Me) and Dark energy/matter etc. The last column anti-gravity is also a good reading.
I also read one paper about frequency dependent bifurcation in height-of-rise of a conducting liquid between two electrodes coated with dielectric(Done in Rochester university) in JMM June 2004 issue. I also located a review on Micropumps in the same issue.
I will now try to answer the questions raised in the previous blog. Lets start with

• What is X-ray crystallography?