Study Mech

Clay water pot are use as water container and also used to cool water from centuries. Without any effort, temperature of water inside pot can be naturally reduced by some temperature. Thermodynamic-ally in water cooling process, mass transfer is comparatively more important than heat transfer. Clay water pot has a porous structure, hence it can be imagined as a clay boundary with a very small holes. Due to very small holes, capillary action take place in water pot surface and this is also reason why many water droplets appear at pot surface and surface remain wet all the time. Due to capillary action, even even if temperature of water is less than temperature of atmospheric air, effect due to higher concentration of water in pot, it will move from higher concentration to lower concentration (atmospheric air). In simple terms, due to capillary effect, inner water particles will reach to the surface by taking energy from all neighbor hood droplets, and then get evaporated to the atmosphe...

Various fluids can be differentiated by their fluid properties, some of the basic fluid properties are density, specific weight, specific gravity, viscosity & specific volume. Let's take a look at the properties of fluids one by one in detail. Fundamental knowledge of fluid properties is very essential to learn Fluid Mechanics (FM) subject. Properties of fluid Density or Mass Density Specific Weight or Weight Density Specific Volume Specific Gravity Viscosity 1. Density or Mass Density The density of the fluid can be defined as a ratio of the mass of fluid to the volume of fluid. Hence it can be call mass per unit volume. It is represented by a symbol ⍴ (rho) and the SI unit of density is kg/m³. Mathematically,   The density of water is taken as 1000 kg/m³ or 1 g/cm³. The density of a liquid is considered as constant with the variation of pressure and temperature. 2. Specific Weight or Weight Density The specific weight of fluid can be defined as the ratio of the weight of...

In human civilization, making different things is an essential activity. Today the word manufacturing we used to describe this activity. The word manufacturing comes from the Latin word manus (hand)  and factus ( make), together it means "made by hand" . Technically we can define manufacturing as a physical or chemical process that we use to alter the geometry, properties, and/or appearance of any substance/ raw material to make desire parts or products. Manufacturing includes the assembly of different parts and components. The process to accomplish manufacturing involves the use of machinery, labor, tools, power, etc. In human evolution, a lot of techniques and processes discovered in manufacturing. Based on how we process raw material, we can simply divide it into subtractive manufacturing, Forming, and Additive manufacturing. 1. Subtractive manufacturing (material removal process)   As the name suggests, subtractive manufacturing involves cutting away or subtract unnec...

Tempering is a heat treatment process in which metal is heated to suitable temperature (below lower re-crystallization temperature ) and then allow to cooling in air. Tempering is secondary heating of martensite. During this process, no change of phase take place because the temperature is not raised beyond the lower critical temperature. Tempering harden the steel with reduction in strength, also it improves toughness and ductility. Tempering is essential process after Quenching. In quenching, due to repid cooling metal get shrink , hence internal stress generated in metal. To remove internal stress, tempering is required. Tempering hardens the steel with reduction in strength , also it increase ductility and toughness.

Quenching also called Hardening, is a heat treatment process in which steel is heated up to austenite temperature (above it's critical temperature), hold for some time and then cooled in water, oil or molten salt (rapid cooling). Due to rapid cooling, it results very hard structure - martensite (hardest form of Steel). fig.- steel component quench in oil. Due to hardening process hardness of steel increases and bitterness also increases. (brittleness increases hence hardened Steel nay not directly use). Quenching is always follow by tempering process. Due to rapid cooling in hardening process metal shape shrink, internal residual stresses are setup. That's the reason why hardening is follow by tempering.