Catalytic of Gas Sensing

        The principle where the reaction of the combustible gases by the oxygen of a catalytic sensors releases the heat on its surface then the catalytic sensors operate on this stages. Then this principle of the catalytic is applied for the detection of the combustible gasses involving the hydrogen. Then the subdivision of the catalytic sensors is the pellistors type, the rmoelectric- type sensors that will be the differentiated here. The pellistors is that element of the hydrogen gas where the sensor is consist to the platinum coils for each embedded in apellet, or the ceramic bead.

Mechanical of Gas Sensing

            When hydrogen absorbed by the metal its occupies the interstitial the sites for the metal lattice which causes to expand as well as therefore the variation of the physical properties of metal. The mechanical hydrogen is the sensor which describe the comprises the micro machined cantilever fabricated which is out for the cleaved edge of the optical fiber. The micro machined hydrogen is the sensors which is based on a different array of the Nano switches in the palladium and has the recently suggested.

Thermal conductivity of Gas Sensing

            The measurements of the thermal conductivity for the analysis of gases have been used for several decades, and thermal conductivity is first time applied on the measurements of hydrogen in the fillings of the airships. Then the principle operations which is based on the measurements of the heat loss, form the hot body in the surrounding gases. Then the detecting resistors which is exposed to gas, and it is being measured while the references resistors which is released into the cambered by containing the references gases. Thermal conductivity sensors are resistant for the poisoning problems of leakages, corrosion as well as in the volatilization that is occurred in the electrolytes of liquids.

Optical of Gas Sensing

            There are certain materials which has the optical properties and it’s vary to interact the hydrogen which is exploited by the means of the hydrogen detection. The optical sensors consisting the optical fiber coated along with the small portions of its lengths in the palladium by using the thin layer of titanium to improve the adhesion of the metal quartz fiber. Most of the hydrogen optical sensors which is still based on the thin film for the palladium among with the chemo chromic oxides which is coated onto the tip by the length of the fiber optics. The Fiber optics sensors is also known as the optodes or the optrodes (Hübert and et.al).