The bellmouth diameter is less than the intake diameter and the exhaust diameter.

The base includes an orifice having an inlet diameter and an outlet diameter.

The shroud has a maximum outer diameter such that the air channel diameter is comprised in the range from 0.82 to 0.9 times the maximum outer diameter.

Similarly, the inner cylinder (3) has a large-diameter entrance and a small-diameter exit.

Each mixed-flow ducted fan unit (400) comprises a duct (102) having an intake diameter, a bellmouth diameter, and an exhaust diameter.

The circular pores have a tapered design having an entrance diameter larger than the exit diameter.

The invention relates to a torque converter, in which the outlet diameter (12') of the turbine or the inlet diameter (13') of the pump is smaller than the passage diameter in the stator (14).

The ratio between the inlet diameter of the impeller and its outlet diameter lies within the range 0.50 - 0.62.

The diffuser has a preferably substantially domed portion with a maximum diameter that is less than the summation of the inlet diameter and the outlet diameter of the orifice.

The outlet diameter is preferably greater than the inlet diameter; and the orifice defines a K- factor of less than 1.0 gpm/psi½.

The outer cylinder (2) is formed into a frustum shape as a whole with a large-diameter entrance and a small-diameter exit.

The seal bore may be slightly wider at the exit; the cup expands to this exit diameter, ensuring an interference fit as the cup travels back through the smaller diameter entry section.

The guide extension catheter may include a proximal shaft (102) having a first outer diameter.

The outer diameter of the target body (23) is in the range 0.05-1 μm.

The rising pipe encompasses a throttle section (31) that is located at the inlet end and has an inlet diameter (Di), a diffuser section (32), and a pipe section (33) having an outlet diameter (Do).