Article: When a molten metal is mixed with another substance, there are two mechanisms that can cause an alloy to form, called atom exchange and the interstitial mechanism. The relative size of each element in the mix plays a primary role in determining which mechanism will occur. When the atoms are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of the other constituent. This is called a substitutional alloy. Examples of substitutional alloys include bronze and brass, in which some of the copper atoms are substituted with either tin or zinc atoms. With the interstitial mechanism, one atom is usually much smaller than the other, so cannot successfully replace an atom in the crystals of the base metal. The smaller atoms become trapped in the spaces between the atoms in the crystal matrix, called the interstices. This is referred to as an interstitial alloy. Steel is an example of an interstitial alloy, because the very small carbon atoms fit into interstices of the iron matrix. Stainless steel is an example of a combination of interstitial and substitutional alloys, because the carbon atoms fit into the interstices, but some of the iron atoms are replaced with nickel and chromium atoms.

Question: Tin or zinc atoms in place of copper atoms create?
Ans: substitutional alloys


Article: Immigration to the United States of Spanish-speaking Cubans began because of Cuba's political instability upon achieving independence. The deposition of Fulgencio Batista's dictatorship and the ascension of Fidel Castro's government in 1959 increased Cuban immigration to the United States, hence there are some one million Cubans in the United States, most settled in southern and central Florida, while other Cubans live in the Northeastern United States; most are fluent in Spanish. In the city of Miami today Spanish is the first language mostly due to Cuban immigration.

Question: What year did most Cubans start coming to America?
Ans: The deposition of Fulgencio Batista's dictatorship and the ascension of Fidel Castro's government in 1959 increased Cuban immigration to the United States


Article: The junior U.S. Senator from Massachusetts, Paul Tsongas, announced in 1984 that he would be stepping down for health reasons. Kerry ran, and as in his 1982 race for Lieutenant Governor, he did not receive the endorsement of the party regulars at the state Democratic convention. Congressman James Shannon, a favorite of House Speaker Tip O'Neill, was the early favorite to win the nomination, and he "won broad establishment support and led in early polling." Again as in 1982, however, Kerry prevailed in a close primary.

Question: What was Tip O'Neill's job?
Ans: House Speaker


Article: Many early LDs were not manufactured properly; sometimes a substandard adhesive was used to sandwich together the two sides of the disc.[citation needed] The adhesive contained impurities that were able to penetrate the lacquer seal layer and chemically attack the metalized reflective aluminium layer, causing it to oxidize and lose its reflective characteristics. This was a problem that was termed "laser rot" among LD enthusiasts, also called "color flash" internally by LaserDisc-pressing plants. Some forms of laser rot could appear as black spots that looked like mold or burned plastic which cause the disc to skip and the movie to exhibit excessive speckling noise. But, for the most part, rotted discs could actually appear perfectly fine to the naked eye.

Question: What problems could occur with laser rot?
Ans:
black spots that looked like mold or burned plastic which cause the disc to skip and the movie to exhibit excessive speckling noise