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There are three main chemical pulping processes: the sulfite process dates back to the 1840s and it was the dominant method extent before the second world war. The kraft process, invented in the 1870s and first used in the 1890s, is now the most commonly practiced strategy, one of its advantages is the chemical reaction with lignin, that produces heat, which can be used to run a generator. Most pulping operations using the kraft process are net contributors to the electricity grid or use the electricity to run an adjacent paper mill. Another advantage is that this process recovers and reuses all inorganic chemical reagents. Soda pulping is another specialty process used to pulp straws, bagasse and hardwoods with high silicate content.
What decade did the sulfite process stop?
A: unanswerable

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An urban runoff facility (SMURFF), the first of its kind in the US, catches and treats 3.5 million US gallons (13,000 m3) of water each week that would otherwise flow into the bay via storm-drains and sells it back to end-users within the city for reuse as gray-water, while bio-swales throughout the city allow rainwater to percolate into and replenish the groundwater supply. The groundwater supply in turn plays an important role in the city's Sustainable Water Master Plan, whereby Santa Monica has set a goal of attaining 100% water independence by 2020. The city has numerous programs designed to promote water conservation among residents, including a rebate of $1.50 per square foot for those who convert water intensive lawns to more local drought-tolerant gardens that require less water.
How much does SMURFF charge per gallon for its gray water?
A: unanswerable

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University of Massachusetts Amherst researchers estimated that from 1970 to 1996, capital flight from 30 Sub-Saharan countries totaled $187bn, exceeding those nations' external debts. (The results, expressed in retarded or suppressed development, have been modeled in theory by economist Mancur Olson.) In the case of Africa, one of the factors for this behavior was political instability, and the fact that new governments often confiscated previous government's corruptly obtained assets. This encouraged officials to stash their wealth abroad, out of reach of any future expropriation. In contrast, Asian administrations such as Suharto's New Order often took a cut on business transactions or provided conditions for development, through infrastructure investment, law and order, etc.
Which researchers studied corruption from Sub-Saharan countries from 1970 to 1996?
A: University of Massachusetts Amherst

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Comparison of a back-translation with the original text is sometimes used as a check on the accuracy of the original translation, much as the accuracy of a mathematical operation is sometimes checked by reversing the operation. But the results of such reverse-translation operations, while useful as approximate checks, are not always precisely reliable. Back-translation must in general be less accurate than back-calculation because linguistic symbols (words) are often ambiguous, whereas mathematical symbols are intentionally unequivocal.
How are mathematical operations ignored?
A:
unanswerable