Season cracking is a form of stress-corrosion cracking of brass cartridge cases originally reported from British forces in India. During the monsoon season, military activity was temporarily reduced, and ammunition was stored in stables until the dry weather returned. Many brass cartridges were subsequently found to be cracked, especially where the case was crimped to the bullet. It was not until 1921 that the phenomenon was explained by Moor, Beckinsale and Mallinson: ammonia from horse urine, combined with the residual stress in the cold-drawn metal of the cartridges, was responsible for the cracking.
Season cracking is characterised by deep brittle cracks which penetrate into affected components. If the cracks reach a critical size, the component can suddenly fracture, sometimes with disastrous results. However, if the concentration of ammonia is very high, then attack is much more severe, and attack over all exposed surfaces occurs. The problem was solved by annealing the brass cases after forming so as to relieve the residual stresses.
The attack takes the form of a reaction between ammonia and copper to form the cuprammonium ion, formula [Cu(NH3)4]2+, a chemical complex which is water-soluble, and hence washed from the growing cracks. The problem of cracking can therefore also occur in copper and any other copper alloy, such as bronze. The tendency of copper to react with ammonia was exploited in making rayon, and the deep blue colour of the aqueous solution of copper(II) oxide in ammonia is known as Schweizer's reagent.[clarification needed]
Although the problem was first found in brass, any alloy containing copper will be susceptible to the problem. It includes copper itself (as used in pipe for example), bronzes and other alloys with a significant copper content. Like all problems with hairline cracks, detection in the early stages of attack is difficult, but the characteristic blue coloration may give a clue to attack. Microscopic inspection will often reveal the cracks, and x-ray analysis using the EDX facility on the scanning electron microscope or SEM should reveal the presence of elemental nitrogen from ammoniacal traces.
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The earthquake's effects were felt as far north as Lebanon and Syria and it was the strongest event in the Jordan Rift Valley since the 1927 Jericho earthquake which was centered near the Dead Sea. The heaviest damage occurred in the resort town of Eilat where seven hotels and 50 other buildings were damaged, and cracks formed in the sidewalks. Fifteen people were treated there for injuries or shock and one man died of a heart attack in Aqaba. In Saudi Arabia two women were reported dead and five deaths were reported in Egypt, with three of them occurring in the gulf resort town of Nuweiba. Eight buildings collapsed in Cairo where, just several years before, the much smaller 1992 Cairo earthquake had a much more destructive impact. One person was killed and two were injured slightly at Al-Bad', Saudi Arabia and damage was reported there as well as the towns of Al-`Ula and Haql. In Eilat, Israel, one person died of a heart attack, several people were injured and property damage, power cuts and liquefaction was observed. In the capital Jerusalem, some damage was also observed.
During several independent field studies cracks and other ground deformations were observed on both the Egyptian and Saudi Arabian sides of the gulf. During a field survey that was done there in 1996, a series of cracks were discovered between 28°35' N and 29°05' N on the Saudi Arabian coast. A field investigation was also done in Egypt in 1996 by seismologist Yann Klinger and others along with the Egyptian Geological Survey and Mining Authority. The most dramatic ground ruptures found were north of Nuweiba along a coastal road.