Question: What property does Rotary technology and Nickel have in common?
Context: Compounds of nickel are chemical compounds containing the element nickel which is a member of the group 10 of the periodic table.  Most compounds in the group have an oxidation state of +2.  Nickel is classified as a transition metal with nickel(II) having much chemical behaviour in common with iron(II) and cobalt(II).  Many salts of nickel(II) are isomorphous with salts of magnesium due to the ionic radii of the cations being almost the same.  Nickel forms many coordination complexes.  Nickel tetracarbonyl was the first pure metal carbonyl produced, and is unusual in its volatility.  Metalloproteins containing nickel are found in biological systems. A rotary stage is a component of a motion system used to restrict an object to a single axis of rotation.  The terms rotary table or rotation stage are often used interchangeably with rotary stage.  All rotary stages consist of a platform and a base, joined by some form of guide in such a way that the platform is restricted to rotation about a single axis with respect to the base.  In common usage, the term rotary stage may or may not also include the mechanism by which the angular position of the platform is controlled relative to the base. Nickel is a chemical element with symbol Ni and atomic number 28.  It is a silvery-white lustrous metal with a slight golden tinge.  Nickel belongs to the transition metals and is hard and ductile.  Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion (passivation).  Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. In metallurgy, melchior is an alloy of copper, mainly with nickel (5–30%).  Its name originates from Italian: "melchior" , which in turn is distorted French: "maillechort" , honoring the French inventors of the alloy, Maillot and Chorier.  The term melchior sometimes refers not only to the copper-nickel alloys, but also ternary alloys of copper with nickel and zinc ("nickel silver") and even a silvered brass.  Melchior is easily deformable by application of pressure, both in the hot and cold state.  After annealing, it has a tensile strength of about 40 kg/mm.  The most valuable property of melchior is its high resistance to corrosion in air, freshwater and seawater.  Increasing content of nickel iron or manganese improves corrosion and cavitation resistance, especially in sea water and atmospheric water vapor.  The alloy of 30% Ni, 0.8% Fe, 1% Mn and 68.2% copper is used in maritime shipping, in particular for the manufacture of condenser tubes.  Thanks to the nickel, melchior, unlike brass and bronze, has not a yellow but a silver color.  Together with high corrosion resistance, this silvery color is preferred for the manufacture of household utensils. Nickel(II) precatalysts are a type of catalyst used in organic reactions.  Many transformations are catalyzed by nickel in organometallic chemistry and in organic synthesis.  Many of these transformations invoke a low valent (generally Ni(0)) species as the active catalyst.  Unfortunately, unlike its counterpart, Pd(0), Ni(0) catalysts are predominantly confined to the glovebox due to their high instability to air and water, with the most common Ni(0) catalyst being Ni(cod).  Additionally, Ni(cod) is more expensive than many Ni(II) salts and the quality varies significantly amongst suppliers.  To make nickel catalysis more accessible and amenable to synthesis and industrial purposes, the use of air-stable Ni(II) precursors has emerged as an important development in this area of research.  This page describes the more commonly employed nickel(II) precatalysts, their synthesis for those not commercially available, and the methods for their reduction to Ni(0) complexes. A nickel titanium (NiTi) rotary file is an engine-driven tapered and pointed endodontic instrument made of nickel titanium alloy with cutting edges used to mechanically shape and prepare the root canals during endodontic therapy or to remove the root canal obturating material while performing retreatment.  The first NiTi file was introduced to the market in 1991.  Superelasticity and shape memory are the properties that make Niti files very flexible.  The high flexibility of Niti files makes them superior to stainless steel files for the purpose of rotary root canal preparation.  The use of NiTi rotary files in dentistry is a common practice. Pulse dialing is a signaling technology in telecommunications in which a direct current local loop circuit is interrupted according to a defined coding system for each signal transmitted, usually a digit.  This lends the method the often used name loop disconnect dialing.  In the most common variant of pulse dialing, decadic dialing, each of the ten Arabic numerals are encoded in a sequence of up to ten pulses.  The most common version decodes the digits 1 through 9, as one to nine pulses, respectively, and the digit 0 as ten pulses.  Historically, the most common device to produce such pulse trains is the rotary dial of the telephone, lending the technology another name, rotary dialing. The Leonardo da Vinci Award was established in 1975 by the Rotary Club of Florence as an annual international prize named after Leonardo da Vinci, to be presented to young people involved in the study of the sciences, technology, literature and the arts.  Among the disciplines recognised and rewarded so far have been painting, sculpture, music, geology, architecture, medicine and nuclear physics.  The 21st Leonardo da Vinci Prize was recently presented to the brilliant young pianist Johan Schmidt.  The prize giving event has been hosted by other European Rotary Clubs in cities such as Tours, Vienna, Athens, Madrid, Würzburg, Brussels and Amsterdam.  This event was last held in London in 1987, when the prize was awarded to the internationally recognised percussionist Evelyn Glennie.  In 1996 1/2 the Rotary Club of London will again be responsible for hosting the prize-giving ceremony. Rotary endodontic files use an engine to rotate the endodontic file during root canal treatment.  The advantages of rotary endodontics are reduced instrumentation times and fewer files used during the procedure.  Commonly Nickel-Titanium files are used because of their greater flexibility which permits increasingly curved roots to be treated.  The use of Ni-ti files comes at a cost of at increased risk of fractured endodontic files, possibly necessitating endodontic retreatment. Rotary Youth Exchange (RYE) is a Rotary International student exchange program for students in secondary school.  Since 1929, Rotary International has sent young people around the globe to experience new cultures.  Currently, about 9,000 students are sponsored by Rotary clubs every year.  Typically, students are sent to another country for a year-long stay, generally living with multiple host families during the year and being expected to perform daily tasks within the household as well as attend school in the host country.  Short term exchange programs are also quite common.  These typically involve direct student exchanges between two families arranged through Rotary to coincide with major school holiday periods.
Answer: flexibility