What is the operating principle of a resistance thermometer based on? The operating principle of resistance thermometers is based on the property of conductors and semiconductors to change their electrical resistance in response to temperature changes in the medium being measured. To measure temperature, the thermometer is placed in the ...

How are gaseous fuels classified? Gaseous fuels can be natural or artificial. Natural gaseous fuels are those extracted from the earth’s crust. For example, Saratov, Stavropol, Gazlinsky gas, etc. Artificial gaseous fuel is one that is obtained by heating coal, peat or wood without access to air. For example, coke ...

What is hydrogen? Hydrogen is a simple gaseous substance; its molecule consists of only 112 hydrogen atoms. Hydrogen is several times lighter than air; 1 m³ of hydrogen weighs 89 g. Hydrogen is the lightest of all gases. Its flash point is 530–590 °C. The heat of combustion of 1 ...

What are stone coals?? Stone coals they are a black, shiny, homogeneous mass, have a white sheen and are grayish-black in color.. The composition of the working mass of hard coals is approximately the following, %: carbon C = 53.9-74.5, hydrogen H = 3.9-4.8, oxygen O = 9.4-3.9, nitrogen N* ...

Semi-anthracite and anthracite coals Semi-anthracite and anthracite coals — these are also hard coals. They date back to the most ancient times and are the oldest fossilized hard coals. They differ from hard coals by having a lower hydrogen content and a higher degree of carbonization. Semi-anthracites and anthracites are ...

Oil Shales – Where Did Shales Form? Shales formed in closed bodies of calm water, where microscopic plant and animal organisms underwent profound changes in the absence of dissolved oxygen. Pelogen settled to the bottom of the reservoirs as a clump-like mass, which over time transformed into organic matter. Shale, ...