The wind chill, which is experienced on a cold, windy day, is related to increased heat transfer from exposed human skin to the surrounding atmosphere. consider a layer of fatty tissue that is 3 mm thick and whose interior surface is maintained at a temperature of 36 c. on a calm day the convection heat transfer coefficient at the outer surface is 25 w/m2⋅k, but with 30 km/h winds it reaches 65 w/m2⋅k. in both cases the ambient air temperature is -15 c.(a) what is the ratio of the heat loss per unit area from the skin for the calm day to that for the windy day? (b) what will be the skin outer surface temperature for the calm day? for the windy day?

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

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.

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.