Article: To prevent the risk of out-of-phase supplies mixing, sections of line fed from different feeder stations must be kept strictly isolated. This is achieved by Neutral Sections (also known as Phase Breaks), usually provided at feeder stations and midway between them although, typically, only half are in use at any time, the others being provided to allow a feeder station to be shut down and power provided from adjacent feeder stations. Neutral Sections usually consist of an earthed section of wire which is separated from the live wires on either side by insulating material, typically ceramic beads, designed so that the pantograph will smoothly run from one section to the other. The earthed section prevents an arc being drawn from one live section to the other, as the voltage difference may be higher than the normal system voltage if the live sections are on different phases and the protective circuit breakers may not be able to safely interrupt the considerable current that would flow. To prevent the risk of an arc being drawn across from one section of wire to earth, when passing through the neutral section, the train must be coasting and the circuit breakers must be open. In many cases, this is done manually by the drivers. To help them, a warning board is provided just before both the neutral section and an advance warning some distance before. A further board is then provided after the neutral section to tell drivers to re-close the circuit breaker, although drivers must not do this until the rear pantograph has passed this board. In the UK, a system known as Automatic Power Control (APC) automatically opens and closes the circuit breaker, this being achieved by using sets of permanent magnets alongside the track communicating with a detector on the train. The only action needed by the driver is to shut off power and coast and therefore warning boards are still provided at and on the approach to neutral sections.

Question: What invention prevented lines from getting mixed?
Ans: Phase Breaks

Article: PS3's hardware has also been used to build supercomputers for high-performance computing. Fixstars Solutions sells a version of Yellow Dog Linux for PlayStation 3 (originally sold by Terra Soft Solutions). RapidMind produced a stream programming package for PS3, but were acquired by Intel in 2009. Also, on January 3, 2007, Dr. Frank Mueller, Associate Professor of Computer science at NCSU, clustered 8 PS3s. Mueller commented that the 256 MB of system RAM is a limitation for this particular application and is considering attempting to retrofit more RAM. Software includes: Fedora Core 5 Linux ppc64, MPICH2, OpenMP v 2.5, GNU Compiler Collection and CellSDK 1.1. As a more cost-effective alternative to conventional supercomputers, the U.S. military has purchased clusters of PS3 units for research purposes. Retail PS3 Slim units cannot be used for supercomputing, because PS3 Slim lacks the ability to boot into a third-party OS.

Question: Who is buying PS3 clusters instead of supercomputers in order to save some money?
Ans: the U.S. military

Article: The distinctive characteristic of English cathedrals is their extreme length, and their internal emphasis upon the horizontal, which may be emphasised visually as much or more than the vertical lines. Each English cathedral (with the exception of Salisbury) has an extraordinary degree of stylistic diversity, when compared with most French, German and Italian cathedrals. It is not unusual for every part of the building to have been built in a different century and in a different style, with no attempt at creating a stylistic unity. Unlike French cathedrals, English cathedrals sprawl across their sites, with double transepts projecting strongly and Lady Chapels tacked on at a later date, such as at Westminster Abbey. In the west front, the doors are not as significant as in France, the usual congregational entrance being through a side porch. The West window is very large and never a rose, which are reserved for the transept gables. The west front may have two towers like a French Cathedral, or none. There is nearly always a tower at the crossing and it may be very large and surmounted by a spire. The distinctive English east end is square, but it may take a completely different form. Both internally and externally, the stonework is often richly decorated with carvings, particularly the capitals.

Question: What is the unique design feature of English cathedrals?
Ans: their extreme length

Article: The U.N. speech was well received but the Soviets never acted upon it, due to an overarching concern for the greater stockpiles of nuclear weapons in the U.S. arsenal. Indeed, Eisenhower embarked upon a greater reliance on the use of nuclear weapons, while reducing conventional forces, and with them the overall defense budget, a policy formulated as a result of Project Solarium and expressed in NSC 162/2. This approach became known as the "New Look", and was initiated with defense cuts in late 1953.

Question: Along with NSC 162/2, what influenced the development of the New Look policy?
Ans:
Project Solarium