In recent years, the technique of producing high vacua has got great importance. Apart from its use in radio and X-ray equipment, it has helped us for investigating the behaviour of atoms and molecules under low pressure conditions. This has the reciprocal effect causing further improvements in exhaust pumps and high vacuum technique, in general. Today we can produce as [...]
List of Vacuum Pressure Measuring Devices [with formula]! 1. Mercury Manometers: These are of two types: i. Differential and Optical Lever Manometers, which are modifications of the ordinary mercury manometers, with more sensitive methods of observation and measurement. These are suitable for measurement of pressures up to 10-3 mm. ii. McLeod Gauge, which is a standard device of its type [...]
The following points highlight the five major types of heat engines. The types are: 1. Steam Engine 2. Reciprocating Steam Engine 3. Internal Combustion Engine 4. Petrol Engine 5. Diesel Engine. Type # 1. Steam Engine: Steam engine converts heat energy into mechanical energy. The heat energy available due to combustion of coal is used to transform water into superheated [...]
Wires are of two groups- (i) ordinary wires and (ii) cables. For electric work conductors are usually made of copper but aluminium conductors are also used mainly because of its low cost. In India a large quantity of copper is imported from other countries. Presently the armature and field coils of different machines and instruments are also made of aluminium [...]
Consider evaporation of water contained in a tube or tank and its subsequent diffusion through the stagnant layer of air over it. Assumptions: (i) The system is under steady state and isothermal conditions (ii) The total pressure within the tube is constant and equal to the outside pressure (iii) Both air and water vapours behave as perfect gases (iv) Air [...]
In this article we will discuss about the general equation for mass transfer. Also learn about equimolal diffusion. General Equation of Mass Diffusion: Consider mass balance of species B diffusing through a control volume (dx × dy × dz) in a solid or stationary fluid medium C. Accumulation of mass of species B in the elemental volume due to its [...]
In this article we will discuss about the meaning and process of mass transfer. Meaning of Mass Transfer: When a system contains two or more components whose concentrations vary from point to point, there is a natural tendency for mass to be transferred, minimising the concentration differences within the system. The transport of one constituent from a region of higher [...]
In this article we will discuss about the Fick’s law of diffusion. Consider a chamber in which two different gas species, B and C, at the same temperature and pressure are initially separated by a partition. The left compartment has a high concentration of gas B (dark circles) whereas the right compartment is rich in gas C (white circles). Higher [...]
In this article we will discuss about the general equation for mass transfer. Also learn about equimolal diffusion. General Equation of Mass Diffusion: Consider mass balance of species B diffusing through a control volume (dx × dy × dz) in a solid or stationary fluid medium C. Accumulation of mass of species B in the elemental volume due to its [...]
When a fluid flows around an object or when the object moves through a body of fluid, there exists a thin layer of fluid close to the solid surface within which shear stresses significantly influence the velocity distribution. The fluid velocity varies from zero at the solid surface to the velocity of free stream flow at a certain distance away [...]