What's a Disc Brake..!!

    Unlike normal Drum brakes which will stops wheel itself, disc brake will decrease speed or stops the rotar, which is directly connected to wheel of bike through hub.

Disc brake consists of 3 main components:

1.Hydraulic fluid along with piston

2.Caliper

3.Break pads

     Whenever break is applied, hydraulic fluid will be released with pressure and the fluid pushes piston to forward direction. Caliper which is connected to piston thus in-turn pushes the break pads on either side of the rotar. This break pads will decrease kinetic energy of the rotar, which is then converted into heat energy. As the rotar is connected to the wheel through the hub, wheel thus comes into halt. 

  If noticed clearly the rotar of the disc break contains pattern of holes. This holes will entrap air which will reduce the heat of the rotar to some extent.

Add on:

There are 4 types of breaking systems as of now:

1. Drum brake

2. Disc brake

3. ABS (Anti locking break system)

4. CBS (Combined breaking system)

    ABS and CBS are advanced breaking technologies where as drum and disc brakes are of commercial brakes. ABS and CBS uses ECU ( electronic control unit) for functioning. HONDA company owned patent for CBS system.

NOTE: Content is limited to author's knowledge and comments are most welcome.

HOW 'MRI' WORKS ??

MRI Stands for Magnetic Resonance Imaging, originally called as nuclear magnetic resonance imaging (NMRI). To avoid negative impressions among people the word nuclear was removed and finally become MRI.

Underlying Physics:

    By weight average human body contains 60% of water (H-O-H). Hydrogen atoms contains single proton in its nucleus and we all know human body is non magnetic material because all the protons in hydrogen nucleus present in body are randomly oriented in different directions to gain net magnetic moment as zero. 

    A 70 kg human body contains 4.7*10²⁷ hydrogen atoms. This high number of atoms helps to get a precise picture of body organs. Whenever these atoms are exposed to a strong magnetic field they will align themselves parallel to the field 

Components of MRI scanner:

1. Main Magnet

2. Gradient Magnets

3. Radio frequency (RF) coil

Working: 

    Main Magnet will produce high magnetic field which will align all hydrogen atoms in parallel direction of the field 

    Gradient magnets are arranged in X, Y and Z directions and hence useful to take images in 3 Dimensions. These Gradient Magnets increase the Magnetic field locally and made protons inside hydrogen atom to spin in a particular frequency locally.

    RF coil will then send RF waves which are reflected back by spinning Hydrogen atoms and reflected back waves are analysed by computer to convert into image format.

Addon:

Capacity of an MRI is measured in Tesla (T) and the main advantage of this method is we can get the data of body without exposing it to X-rays which are harmful to body. As this uses strong magnetic field patients containing metallic replaced parts in their body cannot utilize this. The intensity of magnetic field is so high such that it can even lift a car and hence all precautions should be taken before entering into MRI scanning zone.