Problem: 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.
Railroad operators have shown little interest in returning to what?
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Answer: unanswerable

Problem: In addition, most Grand Lodges require the candidate to declare a belief in a Supreme Being. In a few cases, the candidate may be required to be of a specific religion. The form of Freemasonry most common in Scandinavia (known as the Swedish Rite), for example, accepts only Christians. At the other end of the spectrum, "Liberal" or Continental Freemasonry, exemplified by the Grand Orient de France, does not require a declaration of belief in any deity, and accepts atheists (a cause of discord with the rest of Freemasonry).
Which branch of Freemasonry accepts atheists?
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Answer: "Liberal" or Continental

Problem: The chapter house has an original mid-13th-century tiled pavement. A door within the vestibule dates from around 1050 and is believed to be the oldest in England.[citation needed] The exterior includes flying buttresses added in the 14th century and a leaded tent-lantern roof on an iron frame designed by Scott. The Chapter house was originally used in the 13th century by Benedictine monks for daily meetings. It later became a meeting place of the King's Great Council and the Commons, predecessors of Parliament.
A window in the vestible dates back to when?
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Answer:
unanswerable