Specific Weight (w) of a fluid is the weight per unit volume.
Specific Gravity or Relative Density:
When a liquid is confined in a closed vessel, the ejected vapor molecules accumulated in the space between free liquid pressure and top of the vessel exert a partial pressure on the liquid surface. This pressure in liquid is known as vapor pressure.
The normal compressive stress of any fluid element at rest is known as hydro static pressure which arises as a result of innumerable molecular collisions in the entire fluid. The degree of compressibility of a substance is characterized by bulk modulus of elasticity (K).
Below table shows the social media fans count to top 15 automobile manufacturing companies.
There is no positive correlation between increase in sales and increase in social media fans.
All these data were collected on August 15th, 2014.
Relationship between different temperature scales
K = Kelvin scale
Welding joints are strongest joints used to bear the load. Strength of the welded portion of joint is usually more than the strength of base metal.
Soldering joints are weakest joints out of three. Not meant to bear the load. Use to make electrical contacts generally.
Brazing are weaker than welding joints but stronger than soldering joints. This can be used to bear the load up to some extent.
|2||Temperature required is 3800 degree Centigrade in Welding joints.
||Temperature requirement is up to 450 degree Centigrade in Soldering joints.
||Temperature may go to 600 degree Centigrade in Brazing joints.
|3||Work piece to be joined need to be heated till their melting point.||Heating of the work pieces is not required||Work pieces are heated but below their melting point.|
Assumptions made in LMTD method are
- The Internal Energy (U) is constant throughout the Heat Energy
- Cp and m are constant.
- The Heat Exchanger is perfectly insulated
- The Cross Section of stream is uniform
- No conduction of heat along the tubes of Heat Exchanger
- The Kinetic Energy and Potential Energy changes are negligible
- The flow conditions are steady
- Boyle’s Law
- Charles Law
- Gay-Lussac’s Law
- Avogadro’s law
- Universal Gas Law
Boyle’s law formula
Charles law formula
Gay-Lussac's Law Formula
Avogadro’s law equation
The Five Laws of Friction:
- When a body is moving, the friction is directly proportional to normal force and frictional force direction is perpendicular to the normal force.
- Friction doesn't depend on the area of contact so long as there is an area of contact.
- The coefficient of static friction is slightly higher the value than the coefficient of kinetic friction.
- Kinetic friction is independent of velocity of the body.
- Friction depends upon the type of the surfaces in contact.
U-Tube Manometer :
Differential Manometer :
A U-Tube manometric liquid heavier than the liquid for which the pressure difference is to be measured and is not immiscible with it.
Differential Manometer :
Inverted U-Tube Manometer :
Micro Manometer :
Inclined Manometer :
Centrifugal Governors :
Inertia Governor :
Types of Belt Drives:
Open belt drives :
Advantages of belt drives :
- Belt drives are simple are economical.
- They don't require Parallel shafts.
- Belts drives are provided with overload and jam protection.
- Noise and vibration are damped out. Machinery life is increased because load fluctuations are shock-absorbed.
- They are lubrication-free. They require less maintenance cost.
- Belt drives are highly efficient in use (up to 98%, usually 95%).
- They are very economical, when distance between shafts is very large.
Disadvantages of belt drives :
- In Belt drives, angular velocity ratio is not necessarily constant or equal to the ratio of pulley diameters, because of slipping and stretching.
- Heat buildup occurs. Speed is limited to usually 35 meters per second. Power transmission is limited to 370 kilowatts.
- Operating temperatures are usually restricted to –35 to 85°C.
- Some adjustment of center distance or use of an idler pulley is necessary for wearing and stretching of belt drive compensation.