Context and question: The alkali metal ions are small and mobile; their presence in glass allows a degree of electrical conductivity, especially in molten state or at high temperature. Their mobility decreases the chemical resistance of the glass, allowing leaching by water and facilitating corrosion. Alkaline earth ions, with their two positive charges and requirement for two non-bridging oxygen ions to compensate for their charge, are much less mobile themselves and also hinder diffusion of other ions, especially the alkalis. The most common commercial glasses contain both alkali and alkaline earth ions (usually sodium and calcium), for easier processing and satisfying corrosion resistance. Corrosion resistance of glass can be achieved by dealkalization, removal of the alkali ions from the glass surface by reaction with e.g. sulfur or fluorine compounds. Presence of alkaline metal ions has also detrimental effect to the loss tangent of the glass, and to its electrical resistance; glasses for electronics (sealing, vacuum tubes, lamps...) have to take this in account.
What types of ions does typical glass have?
Answer: alkali and alkaline earth ions
Context and question: Masonic lodges existed in Iraq as early as 1917, when the first lodge under the United Grand Lodge of England (UGLE) was opened. Nine lodges under UGLE existed by the 1950s, and a Scottish lodge was formed in 1923. However, the position changed following the revolution, and all lodges were forced to close in 1965. This position was later reinforced under Saddam Hussein; the death penalty was "prescribed" for those who "promote or acclaim Zionist principles, including freemasonry, or who associate [themselves] with Zionist organisations."
Who opened the only Lodge in Iraq?
Answer: unanswerable
Context and question: The 45 rpm discs also came in a variety known as extended play (EP), which achieved up to 1015 minutes play at the expense of attenuating (and possibly compressing) the sound to reduce the width required by the groove. EP discs were cheaper to produce, and were used in cases where unit sales were likely to be more limited or to reissue LP albums on the smaller format for those people who had only 45 rpm players. LP albums could be purchased 1 EP at a time, with four items per EP, or in a boxed set with 3 EPs or 12 items. The large center hole on 45s allows for easier handling by jukebox mechanisms. EPs were generally discontinued by the late 1950s in the U.S. as three- and four-speed record players replaced the individual 45 players. One indication of the decline of the 45 rpm EP is that the last Columbia Records reissue of Frank Sinatra songs on 45 rpm EP records, called Frank Sinatra (Columbia B-2641) was issued on December 7, 1959. The EP lasted considerably longer in Europe, and was a popular format during the 1960s for recordings by artists such as Serge Gainsbourg and the Beatles.
Why were 45s more popular with jukeboxes?
Answer:
The large center hole