PCBs intended for extreme environments often have a conformal coating, which is applied by dipping or spraying after the components have been soldered. The coat prevents corrosion and leakage currents or shorting due to condensation. The earliest conformal coats were wax; modern conformal coats are usually dips of dilute solutions of silicone rubber, polyurethane, acrylic, or epoxy. Another technique for applying a conformal coating is for plastic to be sputtered onto the PCB in a vacuum chamber. The chief disadvantage of conformal coatings is that servicing of the board is rendered extremely difficult.
A conformal coating can be applied by spraying the PCB or by doing what else to it?
dipping

Meleager and the infantry supported the candidacy of Alexander's half-brother, Philip Arrhidaeus, while Perdiccas, the leading cavalry commander, supported waiting until the birth of Alexander's unborn child by Roxana. After the infantry stormed the palace of Babylon, a compromise was arranged – Arrhidaeus (as Philip III) should become king, and should rule jointly with Roxana's child, assuming that it was a boy (as it was, becoming Alexander IV). Perdiccas himself would become regent (epimeletes) of the empire, and Meleager his lieutenant. Soon, however, Perdiccas had Meleager and the other infantry leaders murdered, and assumed full control. The generals who had supported Perdiccas were rewarded in the partition of Babylon by becoming satraps of the various parts of the empire, but Perdiccas' position was shaky, because, as Arrian writes, "everyone was suspicious of him, and he of them".
Who documented that Perdiccas' was under suspicion? 
Arrian

Catalan has an inflectional grammar, with two genders (masculine, feminine), and two numbers (singular, plural). Pronouns are also inflected for case, animacy[citation needed] and politeness, and can be combined in very complex ways. Verbs are split in several paradigms and are inflected for person, number, tense, aspect, mood, and gender. In terms of pronunciation, Catalan has many words ending in a wide variety of consonants and some consonant clusters, in contrast with many other Romance languages.
What numbers does Catalan have?
singular, plural