by Maryam Hussain How the working of a theoretical engine was proposed? The theoretical heat engine was proposed by Sadi Carnot in 1824 . Heat engines are devices that can convert heat into mechanical energy. Like a Steam engine or Motor vehicle, the working principle of all heat engines is the same in which any working substance gas or vapor is brought back to the initial stage by going through different thermodynamic stages of a cyclic process . Carnot suggested that, if a heat engine goes through fixed thermodynamic stages of a specified process, then the efficiency of the heat engine may be 100% possible. Ideally, this engine gives maximum efficiency. No other engine can be more efficient than this. The specified cyclic process suggested by Carnot is called the Carnot cycle. The Carnot engine has four main parts: 1). First, an insulated, non-conducting stand , so that the transfer of energy is not possible . 2). Second, a hot reservoir with infi...
by Maryam Hussain What is a catalyst? A catalyst is a material that increases the rate and selectivity of a chemical reaction. Whenever a catalytic reaction occurs, cyclic regeneration of the catalyst is required to maintain the catalytic activity. On the basis of the physical phases of reactants and the catalysts, there are two types of catalytic reactions and here only one of those will be described. The type of catalytic reaction in an automobile’s catalytic converter is called heterogeneous catalysis . How do the catalytic reactions occur? In this process, reactants (CO, O 2 , NOx, HC, etc.) adsorb onto the surface of a solid catalyst and are activated by chemical interaction with the catalyst surface, and are then rapidly and selectively transformed to adsorbed products, which desorb from the catalyst surface and go away to the environment through the exhaust pipe. Once the product is desorbed from the surface of the catalyst, the catalyst returns to its orig...