Ruthenium is a lustrous, silvery coloured metal which is unaffected by air, water and acids, but is soluble in fused alkalis.
Rubber Mallet
A hammer with a rubber head.
Rubbing Alcohol
Another name for Propanol.
Rubbing Bearing
A bearing in which the relatively moving parts slide without deliberate lubrication.
A soft and highly reactive member of the alkali group of metals.
Rubidium Bromide


White crystalline solid.

Rubidium Chloride


White crystalline solid.

Rubidium Fluoride


White crystalline solid.

Rubidium Hydride


White crystalline solid.

Rubidium Iodide


White crystalline solid.

Rubidium Oxide


Yellow to yellow brown crystalline solid.

Rubidium Peroxide


White, yellow or dark brown crystalline solid.

Rubidium Sulphide


White, yellow or red.

Rubidium Superoxide


Orange crystalline solid.

The moving part of the vertical tail surface of an aeroplane which provides yaw control or the device in the water on a boat that provides directional control.
Ruled Surface
A surface formed by moving a straight line.
A straight edge with graduation marks used to measure and draw or cut straight lines.
Run-Flat Tyre
A tyre which can run for a certain length of time without air in it.
Running Fit
A class of fit intended for use on machinery with moderate speeds, where accurate location and minimum play are desired.
Running Modes
This is a term used for watching the dynamic behaviour of a system during it's normal mode of operation.
A change in dial indicator position at the surface of the rotor during one rotation of the rotor, used to measure out-of-roundness or indicate a bent shaft.
Failure that is accompanied by significant plastic deformation.
Rupture Strength
Nominal stress developed in a material at rupture.
A corrosion product consisting of hydrated oxides of iron. This term is only applied to ferrous alloys.
Rust Remover
Any chemical substance which removes rust.
Rust Sealer
A rust converter that provides a coat on metal surfaces to protect them against air exposure and thus to prevent continued corrosion.
Rusty Compass
A pair of compasses that are fixed open in a given position.
Rutan, Burt
American aerospace engineer noted for his originality in designing light, strong, unusual-looking, energy-efficient aircraft.
A lustrous, silvery coloured metal which is unaffected by air, water and acids, but is soluble in fused alkalis.
Rutherford, Ernest
The pioneers of subatomic physics.