The operational concept of the power-open, power-close valve is in the name: the valve has some kind of motor or mechanism that needs to be told to open on a call for heat and to close when the space ...

Engineers successfully switch on the third-phase motor of the Devadula Lift Irrigation Scheme, supplying Godavari water to ...

A tissue valve has a ten to 15-year life-span, so they don't like giving them to patients under 65 because it could mean a further operation if it wears out. I was admitted to hospital the day ...