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Boundary-work is part of science studies. In boundary-work, boundaries, demarcations, or other divisions between fields of knowledge are created, advocated, attacked, or reinforced. Such delineations often have high stakes for the participants, [1] and carry the implication that such boundaries are flexible and socially constructed. [citation ...
Boundaries are of four types: fixed, movable, real, and imaginary. For example, in an engine, a fixed boundary means the piston is locked at its position, within which a constant volume process might occur. If the piston is allowed to move that boundary is movable while the cylinder and cylinder head boundaries are fixed.
Rigid boundary – not allowing exchange of work: A mechanically isolated system One example is fluid being compressed by a piston in a cylinder. Another example of a closed system is a bomb calorimeter , a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction.
Thermodynamic work is one of the principal kinds of process by which a thermodynamic system can interact with and transfer energy to its surroundings. This results in externally measurable macroscopic forces on the system's surroundings, which can cause mechanical work, to lift a weight, for example, [1] or cause changes in electromagnetic, [2] [3] [4] or gravitational [5] variables.
In quantum field theory, the Casimir effect (or Casimir force) [1] is a physical force acting on the macroscopic boundaries of a confined space which arises from the quantum fluctuations of a field. The term Casimir pressure is sometimes used when it is described in units of force per unit area.
The boundary layer around a human hand, schlieren photograph. The boundary layer is the bright-green border, most visible on the back of the hand (click for high-res image). In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by
The boundary beyond which events cannot ever be observed is an event horizon, and it represents the maximum extent of the particle horizon. The criterion for determining whether a particle horizon for the universe exists is as follows. Define a comoving distance d p as = ().
An important feature of anti-de Sitter space is its boundary (which looks like a cylinder in the case of three-dimensional anti-de Sitter space). One property of this boundary is that, locally around any point, it looks just like Minkowski space, the model of spacetime used in nongravitational physics. [23]