Recently, the Air Force refined its understanding of the core duties and responsibilities it performs as a Military Service Branch, streamlining what previously were six distinctive capabilities and seventeen operational functions into twelve core functions to be used across the doctrine, organization, training, equipment, leadership, and education, personnel, and facilities spectrum. These core functions express the ways in which the Air Force is particularly and appropriately suited to contribute to national security, but they do not necessarily express every aspect of what the Air Force contributes to the nation. It should be emphasized that the core functions, by themselves, are not doctrinal constructs.
What are not considered doctrinal constructs of the Air Force?
core functions

According to Tabatabaei, there are acceptable and unacceptable esoteric interpretations. Acceptable ta'wil refers to the meaning of a verse beyond its literal meaning; rather the implicit meaning, which ultimately is known only to God and can't be comprehended directly through human thought alone. The verses in question here refer to the human qualities of coming, going, sitting, satisfaction, anger and sorrow, which are apparently attributed to God. Unacceptable ta'wil is where one "transfers" the apparent meaning of a verse to a different meaning by means of a proof; this method is not without obvious inconsistencies. Although this unacceptable ta'wil has gained considerable acceptance, it is incorrect and cannot be applied to the Quranic verses. The correct interpretation is that reality a verse refers to. It is found in all verses, the decisive and the ambiguous alike; it is not a sort of a meaning of the word; it is a fact that is too sublime for words. God has dressed them with words to bring them a bit nearer to our minds; in this respect they are like proverbs that are used to create a picture in the mind, and thus help the hearer to clearly grasp the intended idea.
The implicit meaning of a Quranic verse that is known fully only by God is which type of ta'wil?
Acceptable

Britain had successful tested a new HAA gun, 3.6-inch, in 1918. In 1928 3.7-inch became the preferred solution, but it took 6 years to gain funding. Production of the QF 3.7-inch (94 mm) began in 1937; this gun was used both on mobile carriages with the field army and transportable guns on fixed mountings for static positions. At the same time the Royal Navy adopted a new 4.5-inch (114 mm) gun in a twin turret, which the army adopted in simplified single-gun mountings for static positions, mostly around ports where naval ammunition was available. However, the performance of both 3.7 and 4.5-in guns was limited by their standard fuse No 199, with a 30-second running time, although a new mechanical time fuse giving 43 seconds was nearing readiness. In 1939 a Machine Fuse Setter was introduced to eliminate manual fuse setting.
What was introduced in 1939?
Machine Fuse Setter