paksuntumisilmiöitä

Paksuntumisilmiöitä, also known as thickening phenomena, refers to a range of physical and chemical processes where a fluid or a mixture transitions from a less viscous to a more viscous state, or exhibits non-Newtonian behavior characterized by an increase in viscosity under stress. This phenomenon is distinct from simple viscosity increases due to temperature changes, although temperature can be a contributing factor.

In rheology, paksuntumisilmiöitä are often described as shear thickening, dilatant, or pseudoplastic behavior. Shear thickening fluids, for example, become more viscous when agitated or subjected to shear stress. A common example is a mixture of cornstarch and water, which can feel solid when punched but flows like a liquid when handled gently. This occurs because the solid particles within the fluid become more closely packed and interlocked under stress, impeding flow.

Pseudoplasticity, on the other hand, involves a decrease in viscosity with increasing shear rate, which might seem counterintuitive to the term "paksuntumisilmiöitä" if interpreted strictly as thickening. However, the term can encompass any significant deviation from Newtonian fluid behavior where viscosity is constant. Some interpretations of paksuntumisilmiöitä may focus on reversible thickening processes, such as those seen in certain gels or colloidal suspensions that can regain their lower viscosity state when the stress is removed. Understanding these phenomena is crucial in various industrial applications, including food processing, manufacturing, and the design of protective gear.