Abstract: A gas turbine engine according to an example of the present disclosure may include, among other things, a fan section including a fan having a plurality of fan blades and including an outer housing surrounding the fan blades to establish a bypass duct, a geared architecture, a first spool including a first shaft that interconnects a first compressor and a fan drive turbine, the fan drive turbine driving the fan through the geared architecture. The gas turbine engine is rated to provide an amount of thrust at ground idle, and the gas turbine engine is rated to provide an amount of thrust at maximum takeoff. A thrust ratio is defined as a ratio of the amount of thrust at ground idle divided by the amount of thrust at maximum takeoff. The thrust ratio can be less than or equal to 0.050.

Abstract: A gas turbine engine includes a fan section that includes a fan with fan blades. The fan section drives air along a bypass flow path in a bypass duct. A gear reduction is in driving engagement with the fan and has a gear reduction ratio of greater than 3.0 and less than 4.0. A low spool includes a low pressure turbine that drives a low pressure compressor and drives the gear reduction to drive the fan at a speed slower than the low pressure turbine. A high spool includes a high pressure turbine that drives a high pressure compressor. The high pressure compressor includes a pressure ratio of greater than 6.5 and less than 11.5. A ratio of a product of a pressure ratio of the fan with a pressure ratio of the low pressure compressor pressure to the pressure ratio of the high pressure compressor is greater than 0.35 and less than 0.90. An exhaust gas exit temperature is greater than 900 degrees Fahrenheit and less than 1000 degrees Fahrenheit at maximum take-off.

Abstract: A gas turbine engine according to an example of the present disclosure may include, among other things, a fan section including a fan having a plurality of fan blades and including an outer housing surrounding the fan blades to establish a bypass duct, a geared architecture, a first spool including a first shaft that interconnects a first compressor and a fan drive turbine, the fan drive turbine driving the fan through the geared architecture. The gas turbine engine is rated to provide an amount of thrust at ground idle, and the gas turbine engine is rated to provide an amount of thrust at maximum takeoff. A thrust ratio is defined as a ratio of the amount of thrust at ground idle divided by the amount of thrust at maximum takeoff. The thrust ratio can be less than or equal to 0.050.

Abstract: Embodiments are disclosed for head dimension estimation for spatial audio applications. In an embodiment, a method comprises: obtaining, using one or more processors of an audio headset worn on a user's head, acceleration samples and rotation rate samples over a specified time window while the user rotates their head, the acceleration samples and rotation rate samples measured using motion sensors in the headset; determining a function that relates the acceleration samples to the rotation rate samples; comparing the function to a plurality of reference functions, where each reference function corresponds to a different head dimension in a nominal range of head dimensions; and estimating a dimension of the user's head based on the comparing.

Abstract: Oxygen is injected into the windbox of a fluidized bed ore roaster to form a fluidizing and oxidizing gas stream of elevated oxygen content which is fed into only the feed zone into which the ore to be fluidized is fed.

Abstract: Oxygen is injected into the windbox of a fluidized bed ore roaster to form a fluidizing and oxidizing gas stream of elevated oxygen content which is fed into only the feed zone into which the ore to be fluidized is fed.