An extract on #catofheday
The center hub rotating assembly (CHRA) houses the shaft that connects the compressor impeller and turbine. It also must contain a bearing system to suspend the shaft, allowing it to rotate at very high speed with minimal friction. For instance, in automotive applications the CHRA typically uses a thrust bearing or ball bearing lubricated by a constant supply of pressurized engine oil. The CHRA may also be considered "water-cooled" by having an entry and exit point for engine coolant. Water-cooled models use engine coolant to keep lubricating oil cooler, avoiding possible oil coking (destructive distillation of engine oil) from the extreme heat in the turbine. The development of air-foil bearings removed this risk.
Ball bearings designed to support high speeds and temperatures are sometimes used instead of fluid bearings to support the turbine shaft. This helps the turbocharger accelerate more quickly and reduces turbo lag. Some variable nozzle turbochargers use a rotary electric actuator, which uses a direct stepper motor to open and close the vanes, rather than pneumatic controllers that operate based on air pressure.
Most of the time zones on land are offset from Coordinated Universal Time (UTC) by a whole number of hours (UTC12 to UTC+14), but a few zones are offset by 30 or 45 minutes (e.g. Newfoundland Standard Time is UTC03:30, Nepal Standard Time is UTC+05:45, and Indian Standard Time is UTC+05:30).
Some higher latitude and temperate zone countries use daylight saving time for part of the year, typically by adjusting local clock time by an hour. Many land time zones are skewed toward the west of the corresponding nautical time zones. This also creates a permanent daylight saving time effect.
Conversion between time zones obeys the relationship
"time in zone A" "UTC offset for zone A" = "time in zone B" "UTC offset for zone B",
in which each side of the equation is equivalent to UTC. (The more familiar term "UTC offset" is used here rather than the term "zone designator" used by the standard.)
The conversion equation can be rearranged to
"time in zone B" = "time in zone A" "UTC offset for zone A" + "UTC offset for zone B".
For example, what time is it in Los Angeles (PST, UTC offset= 08) when the New York Stock Exchange opens at 09:30 (EST, 05)?
time in Los Angeles = 09:30 (05:00) + (08:00) = 06:30.
In Delhi (IST, UTC offset= +5:30), the New York Stock Exchange opens at
time in Delhi = 09:30 (05:00) + (+5:30) = 20:00.
These calculations become more complicated near a daylight saving boundary (because the UTC offset for zone X is a function of the UTC time).
The table "Time of day by zone" gives an overview on the time relations between different zones.