Free expansion Throttling Electricity flow through a resistance Heat transfer Plastic deformation. Irreversibilities are of two types: External irreversibilities. These are associated with dissipating effects outside the working fluid. Example: Mechanical friction occurring during a process due to some external source. 2. Internal irreversibilities. These are associated with dissipating effects within the working fluid. Example: Unrestricted expansion of gas, viscosity and inertia of the gas. Lecture 30: Spontaneous Process: Spontaneous processes do not require energy input to proceed, whereas nonspontaneous processes do. A spontaneous process is capable of proceeding in a given direction without needing to be driven by an outside source of energy. Spontaneous changes, also called natural processes, proceed when left to themselves, and in the absence of any attempt to drive them in reverse. The sign convention of changes in free energy follows the general convention for thermodynamic measurements. This means a release of free energy from the system corresponds to a negative change in free energy, but to a positive change for the surroundings. The laws of thermodynamics govern the direction of a spontaneous process, ensuring that if a sufficiently number of individual interactions (like atoms colliding) are involved, then the direction will always be in the direction of increased entropy.
Free expansion Throttling Electricity flow through a resistance Heat transfer Plastic deformation. Irreversibilities are of two types: External irreversibilities. These are associated with dissipating effects outside the working fluid. Example: Mechanical friction occurring during a process due to some external source. 2. Internal irreversibilities. These are associated with dissipating effects within the working fluid. Example: Unrestricted expansion of gas, viscosity and inertia of the gas. Lecture 30: Spontaneous Process: Spontaneous processes do not require energy input to proceed, whereas nonspontaneous processes do. A spontaneous process is capable of proceeding in a given direction without needing to be driven by an outside source of energy. Spontaneous changes, also called natural processes, proceed when left to themselves, and in the absence of any attempt to drive them in reverse. The sign convention of changes in free energy follows the general convention for thermodynamic measurements. This means a release of free energy from the system corresponds to a negative change in free energy, but to a positive change for the surroundings. The laws of thermodynamics govern the direction of a spontaneous process, ensuring that if a sufficiently number of individual interactions (like atoms colliding) are involved, then the direction will always be in the direction of increased entropy.
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