This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

The printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately 0.0042 inches (4.2 mils, 105 μm) thick. PCB designers and fabricators often use heavy copper when design and manufacturing circuit boards in order to increase current-carrying capacity as well as resistance to thermal strains. Heavy copper plated vias transfer heat to external heat sinks. IPC 2152 is a standard for determining current-carrying capacity of printed circuit board traces.
What's the minimum amount of copper a layer in a PCB can have to be considered "heavy copper"?

Regardless of the ability of the Luftwaffe to win air superiority, Adolf Hitler was frustrated that it was not happening quickly enough. With no sign of the RAF weakening, and Luftwaffe air fleets (Luftflotten) taking punishing losses, the OKL was keen for a change in strategy. To reduce losses further, a change in strategy was also favoured to take place at night, to give the bombers greater protection under cover of darkness.[b] On 4 September 1940, in a long address at the Sportspalast, Hitler declared: "And should the Royal Air Force drop two thousand, or three thousand [kilograms ...] then we will now drop [...] 300,000, 400,000, yes one million kilograms in a single night. And should they declare they will greatly increase their attacks on our cities, then we will erase their cities."
The Luftwaffe air fleets were taking what kind of losses?

Due to its position between two unfriendly neighbours, Armenia has close security ties with Russia. At the request of the Armenian government, Russia maintains a military base in the northwestern Armenian city of Gyumri as a deterrent against Turkey.[citation needed] Despite this, Armenia has also been looking toward Euro-Atlantic structures in recent years. It maintains good relations with the United States especially through its Armenian diaspora. According to the US Census Bureau, there are 427,822 Armenians living in the country.
Russia has a military base in which city in Armenia?