Timber refers to wood used for construction works. In fact the word timber is derived from an old English word ‘Timbrian’ which means ‘to build’. A tree that yields good wood for construction is called ‘Standing Timber.’ After felling a tree, its branches are cut and its stem is roughly converted into pieces of suitable …
Cement is the essential component of concrete which, when hydrated, binds the aggregates together to form the hard, strong and monolithic whole that is so useful. Well over 95% of the cement used in concrete throughout the world is Portland cement in its various forms. It is by no means a simple material, and its …
Manufacturing, Properties, Composition of Portland Cement Read More »
Strengthening of Metals Pure metals in the ‘as-cast’ condition after slow cooling are generally soft, have low yield stresses and are very ductile; this is a consequence of the ease of dislocation movement or slip. They are therefore unsuitable for use as a structural material, with perhaps the most critical property for design being the …
Equilibrium Phase Diagrams Most of the materials that we use are not pure but consist of a mixture of one or more constituents. Each of the three material states of gases, liquids and solids may consist of a mixture of different components, e.g. in alloys of two metals. These components are called phases, with each …
Atomic Structure of Elements Atoms, the building block of elements, consist of a nucleus surrounded by a cloud of orbiting electrons. The nucleus consists of positively charged protons and neutral neutrons, and so has a net positive charge that holds the negatively charged electrons, which revolve around it, in position by an electrostatic attraction. The …
Air System of Diesel Engine Fuel, by itself, is of no use whatsoever: it needs oxygen from the air outside in order to burn. At the most basic level, this happens of its own accord: as the piston falls during the induction stroke, air rushes in past the open inlet valve to fill the expanding …
Diesel Engine Working Diesel engines don’t have souls or wills of their own, but depend on a sequence of simple processes. The most fundamental of all those processes takes place deep inside the engine. It’s the one that gives internal combustion engines their name, because it involves burning air and fuel inside a confined space. …
Fuel Supply System in Diesel Engine Diesel fuel doesn’t burn very easily, and in order to burn quickly, cleanly and reliably it has to be in the form of fine droplets, like an aerosol spray. You’ll remember from the previous chapter that the air in a diesel’s cylinders is made hot by being compressed to …
Design is the process of choosing the geometric shape, materials, manufacturing method, and other details needed to completely describe a machine, vehicle, structure, or other engineered item. This process involves a wide range of activities and objectives. It is first necessary to assure that the item is capable of performing its intended function. For example, …
Bending and Torsion Tests Various bending and torsion tests are widely used for evaluating the elastic modulus, strength, shear modulus, shear strength, and other properties of materials. These tests differ in a critical way from tension and compression tests, in that the stresses and strains are not uniform over the cross section of the test …