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A number of materials contract on heating within certain temperature ranges; this is usually called negative thermal expansion, rather than "thermal contraction".For example, the coefficient of thermal expansion of water drops to zero as it is cooled to 3.983 °C (39.169 °F) and then becomes negative below this temperature; this means that water has a maximum density at this temperature, and ...
To distinguish these two thermal expansion equations of state, the latter one is called pressure-dependent thermal expansion equation of state. To deveop the pressure-dependent thermal expansion equation of state, in an compression process at room temperature from (V 0, T 0, P 0) to (V 1, T 0,P 1), a general form of volume is expressed as
The zeroth law of thermodynamics states: If two systems are each in thermal equilibrium with a third, they are also in thermal equilibrium with each other. This statement implies that thermal equilibrium is an equivalence relation on the set of thermodynamic systems under consideration.
Classical thermodynamics considers three main kinds of thermodynamic processes: (1) changes in a system, (2) cycles in a system, and (3) flow processes. (1) A Thermodynamic process is a process in which the thermodynamic state of a system is changed.
Temperature gradients, thermal expansion or contraction and thermal shocks are things that can lead to thermal stress. This type of stress is highly dependent on the thermal expansion coefficient which varies from material to material. In general, the greater the temperature change, the higher the level of stress that can occur.
The Joule effect (during Joule expansion), the temperature change of a gas (usually cooling) when it is allowed to expand freely. The Joule–Thomson effect, the temperature change of a gas when it is forced through a valve or porous plug while keeping it insulated so that no heat is exchanged with the environment.
Increased thermal vibrations produce thermal expansion characterized by the coefficient of thermal expansion (CTE) that is the gradient of the graph of dimensional change versus temperature. CTE depends upon thermal transitions such as the glass transition. CTE of the glassy state is low, while at the glass transition temperature (Tg) increased ...
Thus in 2D and 3D negative thermal expansion in close-packed systems with pair interactions is realized even when the third derivative of the potential is zero or even negative. Note that one-dimensional and multidimensional cases are qualitatively different. In 1D thermal expansion is caused by anharmonicity of interatomic potential only ...