Context and question: A "beer engine" is a device for pumping beer, originally manually operated and typically used to dispense beer from a cask or container in a pub's basement or cellar.
What is the function of a "beer engine"?
Answer: to dispense beer from a cask or container in a pub's basement or cellar
Context and question: In 1904, a British expedition to Tibet, spurred in part by a fear that Russia was extending its power into Tibet as part of The Great Game, invaded the country, hoping that negotiations with the 13th Dalai Lama would be more effective than with Chinese representatives. When the British-led invasion reached Tibet on December 12, 1903, an armed confrontation with the ethnic Tibetans resulted in the Massacre of Chumik Shenko, which resulted in 600 fatalities amongst the Tibetan forces, compared to only 12 on the British side. Afterwards, in 1904 Francis Younghusband imposed a treaty known as the Treaty of Lhasa, which was subsequently repudiated and was succeeded by a 1906 treaty signed between Britain and China.
How many Tibetan troops died at the Massacre of Chumik Shenko?
Answer: 600
Context and question: There has, however, been interest among railroad operators in returning to DC use at higher voltages than previously used. At the same voltage, DC often has less loss than AC, and for this reason high-voltage direct current is already used on some bulk power transmission lines. DC avoids the electromagnetic radiation inherent with AC, and on a railway this also reduces interference with signalling and communications and mitigates hypothetical EMF risks. DC also avoids the power factor problems of AC. Of particular interest to railroading is that DC can supply constant power with a single ungrounded wire. Constant power with AC requires three-phase transmission with at least two ungrounded wires. Another important consideration is that mains-frequency 3-phase AC must be carefully planned to avoid unbalanced phase loads. Parts of the system are supplied from different phases on the assumption that the total loads of the 3 phases will even out. At the phase break points between regions supplied from different phases, long insulated supply breaks are required to avoid them being shorted by rolling stock using more than one pantograph at a time. A few railroads have tried 3-phase but its substantial complexity has made single-phase standard practice despite the interruption in power flow that occurs twice every cycle. An experimental 6 kV DC railway was built in the Soviet Union.
Which type of power does require three-phase transmission?
Answer:
AC