Terminologies

Horse power: Power equal to 33000 ft-ib/min or 550 ft-ib/second or 75 kg-meter/seconds

Friction horse power (FHP): Power required to run the engine at any given speed without producing any useful work. i.e. FHP = THP-BHP

Indicated Horse power (IHP):

IHP = PLAN x4/ 33000×2

Mechanical efficiency = BHP/ IHP x 100 %

• 2 stroke engine develops more power than 4 stroke engine.

Compression ratio

a) Diesel engine: 14:1 to 20:1

b) Petrol engine: 5:1 to 8:1

• Low speed engine: 500 revolutions/second
• Medium speed engine: 1000 revolutions/second
• High speed engine: >1000 revolutions/second

Soil moisture characteristics curve: Graphical representation of soil water potential and moisture content.

Hysteresis: Difference between soil water content and soil water potential when are first wet and after they are dried out and rewetted.

Infiltration: Lateral movement of water inside soil.

Percolation: Entry of water down into difference profile of soil.

Cutan: Modification of texture and structure of soil due to insitu modification of soil surface.