Voice type C). In the lower and upper extremes some contralto voices can sing from D3 (the D below middle C) to B5 (the second B-flat above), one whole step short of the soprano "high C". Contralto tessitura: The contralto voice has the lowest tessitura of the female voices. Contralto subtypes: Contraltos are often broken down into three subcategories: coloratura contralto, lyric contralto, and dramatic contralto. A soprano sfogato is a contralto who has an extended high range reaching the soprano "high C". Countertenor range: The countertenor is the highest male voice. Many countertenor singers perform roles originally written for a castrato
Conventional superconductor a conventional superconductor was 39 K (-234 °C) in magnesium diboride. Conventional superconductor Conventional superconductors are materials that display superconductivity as described by BCS theory or its extensions. This is in contrast to unconventional superconductors, which do not. Conventional superconductors can be either type-I or type-II. Most elemental superconductors are conventional. Niobium and vanadium are type-II, while most other elemental superconductors are type-I. Critical temperatures of some elemental superconductors: Most compound and alloy superconductors are type-II materials. The most commonly used conventional superconductor in applications is a niobium-titanium alloy - this is a type-II superconductor with a superconducting critical temperature