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A thermodynamic cycle occurs when a system is taken through a series of different states, and finally returned to its initial state.
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The Diesel cycle is the thermodynamic cycle which approximates the pressure and volume of the combustion chamber of the Diesel engine, invented by Rudolph Diesel in 1897.
In order to do so, the working substance inside the engine must return to its initial thermodynamic condition after a cycle, which requires to remove the remaining entropy.
Since very few actual implementations of heat engines exactly match their underlying thermodynamic cycles, one could say that a thermodynamic cycle is an ideal case of a mechanical engine.
In thermodynamic terms it follows the Otto engine cycle, so may be thought of as a " four-phase " engine.
The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle.
This consists of a refrigeration cycle, where heat is removed from a low-temperature space or source and rejected to a high-temperature sink with the help of external work, and its inverse, the thermodynamic power cycle.
The resulting refrigerant vapor returns to the compressor inlet at point 1 to complete the thermodynamic cycle.
The above discussion is based on the ideal vapor-compression refrigeration cycle, and does not take into account real-world effects like frictional pressure drop in the system, slight thermodynamic irreversibility during the compression of the refrigerant vapor, or non-ideal gas behavior ( if any ).
In his ideal model, the heat of caloric converted into work could be reinstated by reversing the motion of the cycle, a concept subsequently known as thermodynamic reversibility.
An ' Otto cycle ' is an idealized thermodynamic cycle which describes the functioning of a typical spark ignition reciprocating piston engine, the thermodynamic cycle most commonly found in automobile engines.
Even though these two processes are critical to the functioning of a real engine, wherein the details of heat transfer and combustion chemistry are relevant, for the simplified analysis of the thermodynamic cycle, it is simpler and more convenient to assume that all of the waste-heat is removed during a single volume change.
* Carnot heat engine, the idealised thermodynamic engine based on the Carnot cycle, as studied by Nicolas Léonard Sadi Carnot.
A four-stroke engine, also known as four-cycle, is an internal combustion engine in which the piston completes four separate strokes — intake, compression, power, and exhaust — during two separate revolutions of the engine's crankshaft, and one single thermodynamic cycle.
Internal combustion is based upon a thermodynamic cycle, and a cooler temperature of the intake charge results in a greater thermodynamic expansion and vice versa.
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In this approach melting of an amorphous material occurs when the broken bonds form a percolation cluster with T < sub > g </ sub > dependent on quasi-equilibrium thermodynamic parameters of bonds e. g. on enthalpy ( H < sub > d </ sub >) and entropy ( S < sub > d </ sub >) of formation of bonds in a given system at given conditions:
Latent heat is the heat released or absorbed by a body or a thermodynamic system during a process that occurs without a change in temperature.
Heat transfer is a path function ( or process quantity ), as opposed to a state quantity ; therefore, the amount of heat transferred in a thermodynamic process that changes the state of a system depends on how that process occurs, not only the net difference between the initial and final states of the process.
Supercritical water oxidation or SCWO is a process that occurs in water at temperatures and pressures above a mixture's thermodynamic critical point.
In a quasistatic or equilibrium process, a sufficiently slow transition of a thermodynamic system from one equilibrium state to another occurs such that at every moment in time the state of the system is close to an equilibrium state.
Weight loss occurs when an individual is in a state of negative thermodynamic flux: when the body is exerting more energy ( i. e. in work and metabolism ) than it is consuming ( i. e. from food or other nutritional supplements ), it will use stored reserves from fat or muscle, gradually leading to weight loss.
* Supercritical water oxidation or SCWO, a process that occurs in water at temperatures and pressures above a mixture's thermodynamic critical point
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A transformation of a thermodynamic system can be considered adiabatic when it is quick enough that no significant heat is transferred between the system and the outside.
An enthalpy change describes the change in enthalpy observed in the constituents of a thermodynamic system when undergoing a transformation or chemical reaction.
* Enthalpy of reaction, defined as the enthalpy change observed in a constituent of a thermodynamic system when one mole of substance reacts completely.
* Enthalpy of formation, defined as the enthalpy change observed in a constituent of a thermodynamic system when, one mole of a compound is formed from its elementary antecedents.
* Enthalpy of combustion, defined as the enthalpy change observed in a constituent of a thermodynamic system, when one mole of a substance combusts completely with oxygen.
* Enthalpy of hydrogenation, defined as the enthalpy change observed in a constituent of a thermodynamic system, when one mole of an unsaturated compound reacts completely with an excess of hydrogen to form a saturated compound.
* Enthalpy of neutralization, defined as the enthalpy change observed in a constituent of a thermodynamic system, when one mole of water is produced when an acid and a base react.
* Standard Enthalpy of solution, defined as the enthalpy change observed in a constituent of a thermodynamic system, when one mole of an solute is dissolved completely in an excess of solvent.
A major breakthrough in the understanding of materials occurred in the late 19th century, when the American scientist Josiah Willard Gibbs demonstrated that the thermodynamic properties related to atomic structure in various phases are related to the physical properties of a material.
The driving force for mass transfer is typically a difference in chemical potential, when it can be defined, though other thermodynamic gradients may couple to the flow of mass and drive it as well.
Planck's law very accurately quantitatively describes the power spectral density of electromagnetic radiation, inside a rigid walled cavity in a body made of material that is completely opaque and poorly reflective, when it has reached thermodynamic equilibrium, as a function of absolute thermodynamic temperature alone.
Gibbs's first published work, which appeared in 1873 when he was already 34 years old, was on the geometric representation of thermodynamic quantities.
Electrolyte solutions are normally formed when a salt is placed into a solvent such as water and the individual components dissociate due to the thermodynamic interactions between solvent and solute molecules, in a process called solvation.
Phase transitions occur when the thermodynamic free energy of a system is non-analytic for some choice of thermodynamic variables ( cf.
The standard enthalpy of combustion is the enthalpy change when one mole of a reactant completely burns in oxygen under standard thermodynamic conditions ( although experimental values are usually obtained under different conditions and subsequently adjusted ).
When multiplied by an amount of charge dZ the emf ℰ yields a thermodynamic work term ℰdZ that is used in the formalism for the change in Gibbs free energy when charge is passed in a battery:
The second law of thermodynamics ensures ( through statistical probability ) that two bodies of different temperature, when brought into contact with each other and isolated from the rest of the Universe, will evolve to a thermodynamic equilibrium in which both bodies have approximately the same temperature.
Black used the term in the context of calorimetry when referring to the heat transferred that caused a change of volume while the thermodynamic system was held at constant temperature.
The term latent heat was introduced into calorimetry around 1750 by Joseph Black when studying system changes, such as of volume and pressure, when the thermodynamic system was held at constant temperature in a thermal bath.
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At the opposite extreme, a transformation of a thermodynamic system can be considered isothermal if it is slow enough so that the system's temperature remains constant by heat exchange with the outside.
From these four, a multitude of equations, relating the thermodynamic properties of the thermodynamic system can be derived using relatively simple mathematics.
Every single thermodynamic system exists in a particular state.
Entropy is a thermodynamic property that is the measure of a system ’ s thermal energy per unit temperature that is unavailable for doing useful work.
One can measure the entropy of a system to determine the energy not available for work in a thermodynamic process, such as energy conversion, engines, or machines.
This is the basis of the modern microscopic interpretation of entropy in statistical mechanics, where entropy is defined as the amount of additional information needed to specify the exact physical state of a system, given its thermodynamic specification.
The thermodynamic definition was developed in the early 1850s by Rudolf Clausius and essentially describes how to measure the entropy of an isolated system in thermodynamic equilibrium.
Enthalpy is a measure of the total energy of a thermodynamic system.
In thermodynamics, one can calculate enthalpy by determining the requirements for creating a system from " nothingness "; the mechanical work required, pV, differs based upon the constancy of conditions present at the creation of the thermodynamic system.
Therefore, the change in enthalpy can be devised or represented without the need for compressive or expansive mechanics ; for a simple system, with a constant number of particles, the difference in enthalpy is the maximum amount of thermal energy derivable from a thermodynamic process in which the pressure is held constant.
In thermodynamic open systems, matter may flow in and out of the system boundaries.
The conventional SI system of units is based on seven basic dimensional quantities, namely distance, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity.
0.208 seconds.