Massansiirrossa

Massansiirrossa is a term used in Finnish-language technical literature to denote the set of processes involved in the transport of mass within and between phases. It characterizes how atoms or molecules move from regions of higher chemical potential to lower, across boundaries and interfaces, and sometimes accompanying phase changes. The concept is used across chemical engineering, environmental science, and biology to describe both pollutant migration and device-level transport phenomena.

Mass transfer occurs by diffusion driven by concentration or chemical-potential gradients, by advection in fluid flows, and by mass exchange during phase transitions. In simple single-component systems, the process can be described by Fick’s laws, where the diffusive flux J = -D grad c. In multi-component mixtures, Maxwell–Stefan relations provide a more complete framework by relating fluxes to thermodynamic driving forces. Interface mass transfer requires partitioning at phase boundaries, often described by laws such as Raoult’s or Henry’s, and by mass-transfer coefficients that capture interfacial resistance.

Applications include separation processes such as distillation and extraction, drying and crystallization, and environmental contexts like contaminant transport in soils and aquifers. In physiology and medicine, massansiirrossa explains transport across membranes and within bodily fluids. The term’s usage is most common in Finnish-language sources, though it appears in some international collaborations where it is treated as an umbrella concept for transport phenomena.