How to identify an unsafe system and an unreliable system? what are the intersections?

Afull journal bearing has a journal diameter of 27 mm, with a unilateral tolerance of -0.028 mm. the bushing bore has a diameter of 27.028 mm and a unilateral tolerance of 0.04 mm. the l/d ratio is 0.5. the load is 1.3 kn and the journal runs at 1200 rev/min. if the average viscosity is 50 mpa-s, find the minimum film thickness, the power loss, and the side flow for the minimum clearance assembly.

Determine the stoichiometric and actual air-fuel ratios and the mole flue gas composition for combustion with 15% excess air for raw indiana, pennsylvania raw coal.

Air is flows through an adiabatic nozzle with an inlet pressure of 400 psia at a temperature of 300°f and a velocity of 20 ft/s. the outlet pressure is 40 psia and the velocity is 800 ftl/s. determine the outlet temperature of the air using: a) property tables b) specific heat (using the specific heat value for air at 300°f)