Article: A elevator of this kind uses a vacuum on top of the cab and a valve on the top of the "shaft" to move the cab upwards and closes the valve in order to keep the cab at the same level. a diaphragm or a piston is used as a "brake" if there's a sudden increase in pressure avove the cab. however, to go down, it opens the valve so that the air can pressurize the top of the "shaft", allowing the cab to go down by its own weight. this also means that in case of a power failure, the cab will automatically go down. the "shaft" is made of acrilic, is always round, due to the shape of the vacuum pump turbine. in order to keep the air inside of the cab, rubber seals are used. due to technical limitations, these elevators have a low capacity. they usually allow 1-3 passengers and up to 525 lbs.

Question: What is the shaft made of?
Ans: acrilic


Article: Football and cycling are the most popular sports in Eritrea. In recent years, Eritrean athletes have also seen increasing success in the international arena. Zersenay Tadese, an Eritrean athlete, currently holds the world record in half marathon distance running. The Tour of Eritrea, a multi-stage international cycling event, is held annually throughout the country. The Eritrea national cycling team has experienced a lot of success, winning the continental cycling championship several years in a row. Six Eritrean riders have been signed to international cycling teams, including Natnael Berhane and Daniel Teklehaimanot. Berhane was named African Sportsman of the Year in 2013, ahead of footballers Yaya Touré and Didier Drogba, while Teklehaimanot became the first Eritrean to ride the Vuelta a España in 2012. In 2015 Teklehaimanot won the King of the Mountains classification in the Critérium du Dauphine. Teklehaimanot and fellow Eritrean Merhawi Kudus became the first black African riders to compete in the Tour de France when they were selected by the MTN–Qhubeka team for the 2015 edition of the race, where, on 9 July, Teklehaimanot became the first African rider to wear the polkadot jersey.

Question: Who became the first black African riders to compete in the Tour de France?
Ans: Teklehaimanot and fellow Eritrean Merhawi Kudus


Article: Kolmaš writes that, as the Mongol presence in Tibet increased, culminating in the conquest of Tibet by a Mongol leader in 1642, the Ming emperors "viewed with apparent unconcern these developments in Tibet." He adds that the Ming court's lack of concern for Tibet was one of the reasons why the Mongols pounced on the chance to reclaim their old vassal of Tibet and "fill once more the political vacuum in that country." On the mass Mongol conversion to Tibetan Buddhism under Altan Khan, Laird writes that "the Chinese watched these developments with interest, though few Chinese ever became devout Tibetan Buddhists."

Question: Who's presence increased in Tibet?
Ans: the Mongols


Article: The Bell Telephone Company was created in 1877, and by 1886, more than 150,000 people in the U.S. owned telephones. Bell Company engineers made numerous other improvements to the telephone, which emerged as one of the most successful products ever. In 1879, the Bell company acquired Edison's patents for the carbon microphone from Western Union. This made the telephone practical for longer distances, and it was no longer necessary to shout to be heard at the receiving telephone.

Question: What company did Bell acquire the carbon microphone from?
Ans:
Western Union