839818 - GLOSSARY

CONDENSATION

Changeover of a substance from a vapour state to a liquid state. Occurs due to compression or cooling.

EVAPORATION

The phenomenon when a body changes from a liquid state to a gaseous state. Occurs at any temperature. The lower the temperature, the slower the change.

RESONANCE

Phenomenon whereby the amplitude of oscillations induced in a vibrating system tend to be enhanced (amplified) beyond all limits under certain conditions.

VISCOSITY

Material property whereby the particles in a body encounter resistance as they slide over one another.The internal resistance or frictionis determined by the nature of the body: high in very small solids, low in viscous fluids and zero in gases.In liquids, viscosity drops rapidly as temperature rises.

HARDENED AND TEMPERED STEEL

Heata treatment applied to special steels to improve their mechanical properties: it involves hardening followed by tempering to make the material much stronger.

HARDNESS TEMPERING

This is achieved when the metal's structure is harder and stronger at high temperatures than when cold.

TEMPERING

This involves heating to a temperature %lt; 720°C and then slowly cooling to attenuate the effects of tempering without removing them altogether.In this way, the material returns to conditions that are closer to a stable chemical and physical balance.

SENSOR

A system that reacts when subject to any form of energy by changing its state, i.e. one or more of its properties (resistance, volume, temperature etc.).For example, a sensor is a material that undergoes conductivity changes when submerged in a magnetic field.New-generation sensors are solid-state devices produced using microchips that can take readings from their surroundings and produce a response in the form of electrical signals that can be processed so a final action can be taken.Sensors are therefore able to measure force, acceleration, pressure and temperature of gases, liquids and solids etc.