Glossary – our knowledge from A to Z

Nanotechnology is the study of materials on the atomic or molecular level. The dimensions of nanoparticles lie between those of an atom and a beam of light. Today, the chemical production of nanomaterials (Lotus effect coatings) is included in the term nanotechnology.

All the materials used in glass products have their own natural colours, which can become more noticeable as the thickness of the glass increases. Fluctuations in the colouring are the result of the differing iron oxide content in the glass, the coating process, the coating and changes in the glass thickness and the make-up of the pane.

The natural types of glass are the result of the melting of sands. Obsidian and pumice have volcanic origins, impactites and tektites stem from meteorite impacts and fulgurites are caused by lightning strikes. Of course, seele uses only man-made varieties of glass for constructing façades and roofs of glass which look entirely natural.

Abbreviation for Natural Color System®, a colour model based on the way an observer perceives a colour. NCS notation is made up of blackness, chromaticness and hue components. This colour system permits much finer gradations of colouring than, for example, the RAL colour chart. To date some 1950 hues have been categorised.

This is a compound that together with one or more network formers creates a glass material by altering the microstructure and properties of the glass.

Nickel is a metal and in conjunction with chromium the principal alloying element in corrosion-resistant austenitic steels. Nickel is especially useful in the hardening and tempering of large cross-sections because it enables high strength and optimum toughness values to be achieved.

Nickel forms inter alia bivalent nickel oxide in the presence of oxygen. Nickel oxide is mixed with the glass during production to give it a violet or reddish colouring.

The failure of a pane of toughened safety glass due to the expansion of nickel sulphide inclusions.

Very small, almost spherical impurities in glass. Under certain circumstances they can cause spontaneous failure of toughened safety glass panes.

A chemical method for hardening the surface of steel with the help of nitrogen. The surface can achieve a heat resistance of up to 500°C. The subsequent oxidation results in corrosion protection. Nitrided components are used, for example, in highly stressed bearings with slip planes in cable-net façades.

See: nitriding.

Nitrogen is a colourless, odourless and tasteless gas. It is a chemical element with the symbol N and atomic number 7. In materials engineering liquid nitrogen is used to eliminate austenite from hardened steels.

This is the point in a structure at which several components meet. The term node is frequently used in conjunction with the intersection of linear steel components. From the structural engineering viewpoint, any chosen point in a structure or component can be regarded as a node.

A noise barrier of glass is used to attenuate noise originating from a linear or planar source so that at the place to be protected the noise is weakened to such an extent that the limit value specified in the relevant legislation is complied with.

This is the minimum sound level, and perceived as “quiet”, measured at a location at a certain time:

The inside diameter of a pipe or a pipe fitting such as a valve.

Nominal sizes are theoretical figures that specify the mathematically exact distance between two measurement or reference points. See: actual size.

This term is used exclusively for heavy metals based on copper.

This is the collective term covering all pure metals (apart from iron) and all metal alloys whose main constituent is not iron. We categorise them according to their density: light metals (< 5 g/cm²) and heavy metals (> 5 g/cm²).

This type of connection is produced by the application of a force generated by a suitable prestress or preload. The connection between the parts is maintained purely by an adhesive force. The forces to be transferred act tangentially to the mating faces of the parts.

This is used for casting steel components into concrete, for filling joints between prefabricated components and concrete, and for closing off openings and joints in concrete. A space must be left for the grout between the steel and the concrete. Air in this space must be able to escape. This grout does not shrink once it has cured.

A normal force acts in the direction of the longitudinal axis of a member, i.e. perpendicular to the cross-section. A normal compressive force compresses the member, a normal tensile force stretches it. A normal force causes axial stresses in the cross-section. At a sufficiently large distance from the point of application of the force, the distribution of the stress can be assumed to be constant.

German abbreviation for natural smoke and heat vent (natürliches Rauch- und Wärmeabzugs-Gerät). Such vents dissipate hot gases and fumes in the event of a fire in order to create smoke-free zones at floor level and in escape routes. DIN EN 12101-2 specifies the design and use of these vents.