| Zero initial conditions |
The assumption normally made in control engineering that up to a start time defined as t = 0, all variables have zero value. |
| Zero time |
The time when the given loading or constraint conditions are initially obtained in creep or stressrelaxation tests, respectively. |
| Zero-gravity |
The situation in which there is no force of gravity (i.e. weightlessness). |
| Zirconia-toughened alumina composites |
(ZTA composites) Ceramic composites based on aluminium oxide to which zirconium oxide is added, resulting in improved fracture toughness. |
| Zone melting (zone refining) |
A process of purification of materials in which a narrow molten zone is moved along the length of the material, resulting in impurities being segregated at one end. |
