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10)Described: What to expect on Republic Morning 2021and what not to

India Republic Day -- Republic Day 2021: In 2020it was the agitation from the Citizenship Amendment Act (CAA). Nowthousands of farmersgenerally from Punjab and Haryanahave been camping at the borders of Delhi for more than 2 monthsdemanding the Centre repeal the three farm laws. For the second year in a stripRepublic Day celebrations from the national capital will be kept under the shadow of raging protests against laws approved by the Centre. In 2020it was the agitation from the Citizenship Amendment Act (CAA). This timethousands of farmersgenerally from Punjab and Haryanahave been camping at the borders of Delhi for more than 2 monthsdemanding the Centre repeal the three farm laws. This years Republic Day march will also be the first major open public event in pandemic moments. What is new this year The big event will be pared down the number of spectatorsthe size of walking contingents and other side attractions. The spectator size has become reduced to 25000 from around 1 . 25 l...
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Heat of combustion

The heating value (or energy value or calorific value ) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard conditions. The chemical reaction is typically a hydrocarbon or other organic molecule reacting with oxygen to form carbon dioxide and water and release heat. It may be expressed with the quantities: There are two kinds of heat of combustion, called higher and lower heating value, depending on how much the products are allowed to cool and whether compounds like H 2 O are allowed to condense. The values are conventionally measured with a bomb calorimeter. They may also be calculated as the difference between the heat of formation Δ H ⦵ f of the products and reactants (though this approach is somewhat artificial since most heats of formation are calculated from ...
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Ways of determination

Higher heating value edit The quantity known as higher heating value ( HHV ) (or gross energy or upper heating value or gross calorific value ( GCV ) or higher calorific value ( HCV )) is determined by bringing all the products of combustion back to the original pre-combustion temperature, and in particular condensing any vapor produced. Such measurements often use a standard temperature of 25 °C (77 °F; 298 K) citation needed . This is the same as the thermodynamic heat of combustion since the enthalpy change for the reaction assumes a common temperature of the compounds before and after combustion, in which case the water produced by combustion is condensed to a liquid. The higher heating value takes into account the latent heat of vaporization of water in the combustion products, and is useful in calculating heating values for fuels where condensation of the reaction products is practical (e.g., in a gas-fired boiler used for space heat). In other words, HHV assumes all the wa...
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Gross heating value

Gross heating value accounts for water in the exhaust leaving as vapor, and includes liquid water in the fuel prior to combustion. This value is important for fuels like wood or coal, which will usually contain some amount of water prior to burning.
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Measuring heating values

The higher heating value is experimentally determined in a bomb calorimeter. The combustion of a stoichiometric mixture of fuel and oxidizer (e.g. two moles of hydrogen and one mole of oxygen) in a steel container at 25 °C (77 °F) is initiated by an ignition device and the reactions allowed to complete. When hydrogen and oxygen react during combustion, water vapor is produced. The vessel and its contents are then cooled to the original 25 °C and the higher heating value is determined as the heat released between identical initial and final temperatures. When the lower heating value (LHV) is determined, cooling is stopped at 150 °C and the reaction heat is only partially recovered. The limit of 150 °C is based on acid gas dew-point. Note: Higher heating value (HHV) is calculated with the product of water being in liquid form while lower heating value (LHV) is calculated with the product of water being in vapor form .
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Relation between heating values

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The difference between the two heating values depends on the chemical composition of the fuel. In the case of pure carbon or carbon monoxide, the two heating values are almost identical, the difference being the sensible heat content of carbon dioxide between 150 °C and 25 °C (sensible heat exchange causes a change of temperature. In contrast, latent heat is added or subtracted for phase transitions at constant temperature. Examples: heat of vaporization or heat of fusion). For hydrogen the difference is much more significant as it includes the sensible heat of water vapor between 150 °C and 100 °C, the latent heat of condensation at 100 °C, and the sensible heat of the condensed water between 100 °C and 25 °C. All in all, the higher heating value of hydrogen is 18.2% above its lower heating value (142 MJ/kg vs. 120 MJ/kg). For hydrocarbons the difference depends on the hydrogen content of the fuel. For gasoline and diesel the higher heating value exceeds the lower heating value by abo...
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Usage of terms

Engine manufacturers typically rate their engines fuel consumption by the lower heating values since the exhaust is never condensed in the engine. American consumers should be aware that the corresponding fuel-consumption figure based on the higher heating value will be somewhat higher. The difference between HHV and LHV definitions causes endless confusion when quoters do not bother to state the convention being used. since there is typically a 10% difference between the two methods for a power plant burning natural gas. For simply benchmarking part of a reaction the LHV may be appropriate, but HHV should be used for overall energy efficiency calculations if only to avoid confusion, and in any case, the value or convention should be clearly stated.
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