Vein bursting is a common condition. I would recommend that you discuss this with your doctor as it may be a a sign of an underlying disorder that requires treatment. First of all, everyone occasionally experiences veins bursting. This results in an ecchymosis, or a bruise.
Couplings & Flexible Shafts. Couplings are devices used to connect two shafts together and are divided into two categories: Rigid and Flexible. Both are used for the purpose of transmitting power, rigid couplings being more limited in applications as compared to flexible couplings.
Loose coupling occurs when the dependent class contains a pointer only to an interface, which can then be implemented by one or many concrete classes. The dependent class's dependency is to a contract specified by the interface; a defined list of methods and/or properties that implementing classes must provide.