Search results
Results From The WOW.Com Content Network
There are three major requirements of creating a desirable surface for adhesive bonding of plastics: the weak boundary layer of the given material must be removed or chemically modified to create a strong boundary layer; the surface energy of the adherend should be higher than the surface energy of the adhesive for good wetting; and the surface profile can be improved to provide mechanical ...
Early interlocking systems used mechanical devices both to operate the signalling appliances and to ensure their safe operation. Beginning around the 1930s, electrical relay interlockings were used. Since the mid 1980s, new interlocking systems have tended to be of the electronic variety. Microprocessors decide what point switch movements are ...
Absolute Block Telegraph for double lines came in 1879, Saxby & Farmer's mechanical interlocking in 1881, Tyer's Electric Tablet in 1888 (lasting until 1959) and the Electric Staff system in 1891. Tyer's One-Wire Block began to replace the original Preece's Patent instruments from 1891. Sykes' Lock & Block was used on a few suburban sections ...
Trapped key interlock switchgear door. An interlock is a feature that makes the state of two mechanisms or functions mutually dependent. It may consist of any electrical or mechanical devices, or systems. In most applications, an interlock is used to help prevent any damage to the machine or to the operator handling the machine.
Entrance-Exit Interlocking (NX) was the original brand name of the first generation relay-based centralized traffic control (CTC) interlocking system introduced in 1936 by GRS [13] (represented in Europe by Metropolitan-Vickers). The advent of all electric interlocking technology allowed for more automated route setting procedures as opposed to ...
Also, both the adhesion-forming interactions between adhesive and substrate, as well as the inter-intramolecular interactions causing the cohesion, can be adversely affected by external influences (including temperature, humidity, chemicals, radiation, mechanical stress). The degree of impairment depends on the nature of the conditions and ...
The adhesion of concrete or grout to prestressing strands, wires or bars, or to unstressed reinforcement, either through friction or mechanical interlock. [1]: 9 bond strength The resistance to separation of hardened concrete or grout from prestressing strands, wires or bars, or from unstressed reinforcement.
This sign is a blue square board with a white St Andrew's cross on it (or a yellow board with a black cross, if provided in conjunction with a temporary speed restriction). With mechanical signalling, the AWS system was installed only at distant signals but, with multi-aspect signalling, it is fitted at all main line signals.