The problem: Answer a question about this article:
Hydrogen is highly soluble in many rare earth and transition metals and is soluble in both nanocrystalline and amorphous metals. Hydrogen solubility in metals is influenced by local distortions or impurities in the crystal lattice. These properties may be useful when hydrogen is purified by passage through hot palladium disks, but the gas's high solubility is a metallurgical problem, contributing to the embrittlement of many metals, complicating the design of pipelines and storage tanks.
When are these useful?
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The answer: when hydrogen is purified by passage through hot palladium disks


The problem: Answer a question about this article:
The four-year, full-time undergraduate program comprises the majority of enrollments at the university and emphasizes instruction in the arts and sciences, plus the professions of engineering, journalism, communication, music, and education. Although a foundation in the liberal arts and sciences is required in all majors, there is no required common core curriculum; individual degree requirements are set by the faculty of each school. Northwestern's full-time undergraduate and graduate programs operate on an approximately 10-week academic quarter system with the academic year beginning in late September and ending in early June. Undergraduates typically take four courses each quarter and twelve courses in an academic year and are required to complete at least twelve quarters on campus to graduate. Northwestern offers honors, accelerated, and joint degree programs in medicine, science, mathematics, engineering, and journalism. The comprehensive doctoral graduate program has high coexistence with undergraduate programs.
Which 4-year program comprises the majority of enrollments at Northwestern?
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The answer: full-time undergraduate


The problem: Answer a question about this article:
On 21 December 2011 the bank instituted a programme of making low-interest loans with a term of three years (36 months) and 1% interest to European banks accepting loans from the portfolio of the banks as collateral. Loans totalling €489.2 bn (US$640 bn) were announced. The loans were not offered to European states, but government securities issued by European states would be acceptable collateral as would mortgage-backed securities and other commercial paper that can be demonstrated to be secure. The programme was announced on 8 December 2011 but observers were surprised by the volume of the loans made when it was implemented. Under its LTRO it loaned €489bn to 523 banks for an exceptionally long period of three years at a rate of just one percent. The by far biggest amount of €325bn was tapped by banks in Greece, Ireland, Italy and Spain. This way the ECB tried to make sure that banks have enough cash to pay off €200bn of their own maturing debts in the first three months of 2012, and at the same time keep operating and loaning to businesses so that a credit crunch does not choke off economic growth. It also hoped that banks would use some of the money to buy government bonds, effectively easing the debt crisis.
How much does the ECB have to have to pay off it's own debts?
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The answer: €200bn


The problem: Answer a question about this article:
About 10,000 years ago, when the ice melted after the last glacial period, late Paleolithic communities were established along the lake shores and in cave systems. Evidence of human habitation has been found in caves near Vercors, close to Grenoble; in Austria the Mondsee culture shows evidence of houses built on piles to keep them dry. Standing stones have been found in Alpine areas of France and Italy. The rock drawings in Valcamonica are more than 5000 years old; more than 200,000 drawings and etchings have been identified at the site.
What has been found in caves near Vercors?
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The answer:
Evidence of human habitation