Stlaení

Stlaení (often written stlačení in Czech) is the process of reducing the volume of a material or system by applying external pressure, resulting in increased density and decreased porosity.

In physics and engineering, compression applies to gases, liquids, and solids. For gases, compression raises pressure and can raise temperature, following gas laws such as PV = nRT. For solids, stlaení may be elastic or plastic, depending on the material and applied stress.

Key quantities include the bulk modulus B, defined as B = -V dP/dV, and compressibility κ = 1/B. In many contexts, density changes with pressure; in gases, the ideal-gas relation gives P ∝ ρ at fixed temperature, while the temperature change depends on the process (isothermal vs adiabatic).

Common applications range from gas compression in engines and compressors to hydraulic and pneumatic systems; in materials science, cold and hot isostatic pressing densify powders; in geotechnical engineering, soil compaction increases strength and stability.

Techniques include isothermal and adiabatic compression, as well as industrial methods such as isostatic pressing, cold pressing, and hot pressing. Accurate control of temperature, pressure, and deformation is essential to avoid damage or unwanted phase changes.