Here is a question about this article: The relative reactivity of zinc and its ability to attract oxidation to itself makes it an efficient sacrificial anode in cathodic protection (CP). For example, cathodic protection of a buried pipeline can be achieved by connecting anodes made from zinc to the pipe. Zinc acts as the anode (negative terminus) by slowly corroding away as it passes electric current to the steel pipeline.[note 2] Zinc is also used to cathodically protect metals that are exposed to sea water from corrosion. A zinc disc attached to a ship's iron rudder will slowly corrode, whereas the rudder stays unattacked. Other similar uses include a plug of zinc attached to a propeller or the metal protective guard for the keel of the ship.
What is the answer to this question: Connecting anodes made from zinc to buried pipe creates what?
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So... cathodic protection


Here is a question about this article: Richard Sander claims that by artificially elevating minority students into schools they otherwise would not be capable of attending, this discourages them and tends to engender failure and high dropout rates for these students. For example, about half of black college students rank in the bottom 20 percent of their classes, black law school graduates are four times as likely to fail bar exams as are whites, and interracial friendships are more likely to form among students with relatively similar levels of academic preparation; thus, blacks and Hispanics are more socially integrated on campuses where they are less academically mismatched. He claims that the supposed "beneficiaries" of affirmative action – minorities – do not actually benefit and rather are harmed by the policy. Sander's claims have been disputed, and his empirical analyses have been subject to substantial criticism. A group including some of the country's lead statistical methodologists told the Supreme Court that Sander's analyses were sufficiently flawed that the Court would be wise to ignore them entirely. At the same time many scholars have found that minorities gain substantially from affirmative action.
What is the answer to this question: What is the failure rate for black law school graduates compared to whites for the bar exam?
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So... four times


Here is a question about this article: Solar concentrating technologies such as parabolic dish, trough and Scheffler reflectors can provide process heat for commercial and industrial applications. The first commercial system was the Solar Total Energy Project (STEP) in Shenandoah, Georgia, USA where a field of 114 parabolic dishes provided 50% of the process heating, air conditioning and electrical requirements for a clothing factory. This grid-connected cogeneration system provided 400 kW of electricity plus thermal energy in the form of 401 kW steam and 468 kW chilled water, and had a one-hour peak load thermal storage. Evaporation ponds are shallow pools that concentrate dissolved solids through evaporation. The use of evaporation ponds to obtain salt from sea water is one of the oldest applications of solar energy. Modern uses include concentrating brine solutions used in leach mining and removing dissolved solids from waste streams. Clothes lines, clotheshorses, and clothes racks dry clothes through evaporation by wind and sunlight without consuming electricity or gas. In some states of the United States legislation protects the "right to dry" clothes. Unglazed transpired collectors (UTC) are perforated sun-facing walls used for preheating ventilation air. UTCs can raise the incoming air temperature up to 22 °C (40 °F) and deliver outlet temperatures of 45–60 °C (113–140 °F). The short payback period of transpired collectors (3 to 12 years) makes them a more cost-effective alternative than glazed collection systems. As of 2003, over 80 systems with a combined collector area of 35,000 square metres (380,000 sq ft) had been installed worldwide, including an 860 m2 (9,300 sq ft) collector in Costa Rica used for drying coffee beans and a 1,300 m2 (14,000 sq ft) collector in Coimbatore, India, used for drying marigolds.
What is the answer to this question: What is one of the oldest uses of solar energy?
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So...
use of evaporation ponds to obtain salt from sea water