THE MECH ENGG

MODES OF HEAT TRANSFR : There are three modes of heat transfer 1.CONDUCTION 2.CONVECTION 3.RADIARION CONDUCTION :- I n this mode ,heat transfer from one part to another part of opaque solid without appreciable displacment of the particles. Conduction involves the transfer of kinetic energy from one moleculer to an adjacent molecular. It is the only mechanism of heat flow in an opaque solid . Conduction always requires a material medium.

Q. WHAT IS DIODE ?  A  diode  is a semiconductor device that essentially   acts as a one-way switch for current. It allows   current to flow easily in one direction, but   severely restricts current from flowing in the   opposite direction. Diodes are also known as  rectifiers  because they change alternating current (ac) into pulsating direct current (dc). Diodes have polarity, determined by an  anode (positive lead) and  cathode  (negative lead). When a diode allows current flow, it is  forward-biased . When a diode is  reverse-biased , it acts as an insulator and does not permit current to flow.

What is BEAM ?  Beam is a structural member that is designed to resist force acting at right angles to its axis. TYPES OF BEAM Beams are of cattigoroise  according to the types of support on which it rest  1. SIMPLY SUPPORTED BEAM  2. CANTILEVER BEAM  3.FIXED BEAM  4.OVERHANGING BEAM

TYPES OF MOLD Expandable Mold Composite Mold Permanent Mold

Q. WHAT IS TRANSFORMER ?      A Transformer is a static device which transfer electrical energy between  two or more electrical circuit interlinked by a common magnetic circuit.                                                                fig-TRANSFORMER

Q. WHAT IS CASTING ? ANS- Casting is a very important manufacturing process. It is used to produce any product as a single unit. *  In casting ,metal is first  melted with the help of a suitable furnace.Then the metal is poured     in a cavity similar to the size of object being made.where it is lefted to solidify.After   solidification the cavity is destroyed to take out the solid object from it.  The solid object as well   as the process are called casting.