Article: The US ended World War I with two 3-inch AA guns and improvements were developed throughout the inter-war period. However, in 1924 work started on a new 105 mm static mounting AA gun, but only a few were produced by the mid-1930s because by this time work had started on the 90 mm AA gun, with mobile carriages and static mountings able to engage air, sea and ground targets. The M1 version was approved in 1940. During the 1920s there was some work on a 4.7-inch which lapsed, but revived in 1937, leading to a new gun in 1944.

Question: When were improvements developed for these guns?
Ans: throughout the inter-war period


Article: In 1906, precipitation hardening alloys were discovered by Alfred Wilm. Precipitation hardening alloys, such as certain alloys of aluminium, titanium, and copper, are heat-treatable alloys that soften when quenched (cooled quickly), and then harden over time. After quenching a ternary alloy of aluminium, copper, and magnesium, Wilm discovered that the alloy increased in hardness when left to age at room temperature. Although an explanation for the phenomenon was not provided until 1919, duralumin was one of the first "age hardening" alloys to be used, and was soon followed by many others. Because they often exhibit a combination of high strength and low weight, these alloys became widely used in many forms of industry, including the construction of modern aircraft.

Question: One of the first "age hardening" alloys used were called?
Ans: duralumin


Article: During the 18th century, systems of plant identification were developed comparable to dichotomous keys, where unidentified plants are placed into taxonomic groups (e.g. family, genus and species) by making a series of choices between pairs of characters. The choice and sequence of the characters may be artificial in keys designed purely for identification (diagnostic keys) or more closely related to the natural or phyletic order of the taxa in synoptic keys. By the 18th century, new plants for study were arriving in Europe in increasing numbers from newly discovered countries and the European colonies worldwide. In 1753 Carl von Linné (Carl Linnaeus) published his Species Plantarum, a hierarchical classification of plant species that remains the reference point for modern botanical nomenclature. This established a standardised binomial or two-part naming scheme where the first name represented the genus and the second identified the species within the genus. For the purposes of identification, Linnaeus's Systema Sexuale classified plants into 24 groups according to the number of their male sexual organs. The 24th group, Cryptogamia, included all plants with concealed reproductive parts, mosses, liverworts, ferns, algae and fungi.

Question: What is the term for keys used for identification?
Ans: diagnostic keys


Article: In the 7th–9th centuries Rome fell under the influence of Byzantine art, noticeable on the mosaics of Santa Prassede, Santa Maria in Domnica, Sant'Agnese fuori le Mura, Santa Cecilia in Trastevere, Santi Nereo e Achilleo and the San Venanzio chapel of San Giovanni in Laterano. The great dining hall of Pope Leo III in the Lateran Palace was also decorated with mosaics. They were all destroyed later except for one example, the so-called Triclinio Leoniano of which a copy was made in the 18th century. Another great work of Pope Leo, the apse mosaic of Santa Susanna, depicted Christ with the Pope and Charlemagne on one side, and SS. Susanna and Felicity on the other. It was plastered over during a renovation in 1585. Pope Paschal I (817–824) embellished the church of Santo Stefano del Cacco with an apsidal mosaic which depicted the pope with a model of the church (destroyed in 1607).

Question: Which mosaic survived through the 9th century, and then had a copy made in the 18th?
Ans:
Triclinio Leoniano