Hand Pump

Water hand pumps are manually operated pumps; They are used for bringing water from earth underground to earth surface and is used in every country for a variety of industrial, marine, irrigation and household purposes.
Image shown below is the typical design of Hand Pump.

Hand Pump Parts:

• Handle
• Pump rod
• water outlet
• Piston
• Piston valve
• Foot valve
• Rising main
• Suction lift

Principle of Hand Pump:

There are several types of water hand pumps. Most commonly used hand pumps are positive displacement pumps, positive displacement pumps have reciprocating plungers or pistons. In a piston pump, the piston is fitted with the piston  valve (non-return valve) and slides vertically up and down within a cylinder which is fitted with a foot valve (non-return valve). Applying the force on handle of the water pump causes vertical movement of pump rods that are connected to the piston.
When the piston of the pump moves upwards, the piston valve closes and a vacuum is created below the piston valve, Piston valve causes water to be drawn into the cylinder through the foot valve, which opens. Simultaneously, water above the piston, held up by the closed piston valve, is displaced upwards. In a suction hand pump water flows outward through the delivery outlet; in a hand pump with a submerged cylinder it is forced up the rising main.
When the piton moves downwards in hand pump, the foot valve closes to prevent back flow of water and the piston valve opens to allowing the piston to move down through the water in the cylinder.

Vibration In Mobile Phones

Vibration is a mechanical phenomenon, It is a movement first in one direction and then back again in the reverse direction.

e.g: the motion of a swinging pendulum, the motion of a tuning fork.

Any simple vibration is described by three factors: its amplitude; its frequency and rate of oscillation.

Some of the general terms you will come across while studying on vibration topic are Oscillatory motion, Simple Harmonic Motion, Periodic Motion. now we will see the above mentioned terms in brief.

Oscillatory Motion :

Oscillatory motion is described as motion that repeats itself in a regular intervals of time. for example a sine wave or cos wave or pendulum. The time taken for an oscillation to occur is often referred to as the oscillatory period.

Simple Harmonic Motion :

Simple Harmonic Motion is periodic motion in which the restoring force is directly proportional to the displacement.

F = -k*x

A simple harmonic motion of a pendulum is an example of motion that is frequently used by physicists as a mean of explaining systems which are part of potential energy.
e.g such as the oscillation of a spring.

- See more at: http://www.me-mechanicalengineering.com/2014/03/Fundamental-concepts-of-Vibration.html#sthash.6T86K5Um.dpuf