A coal-burning electric generating plant emits 1.5 kg/min of SO2 from a stack with an effective height of 65m. on a thinly overcast evening, with a wind speed of 5.0 m/s, what will be the ground level concentration of SO2 500m directly downwind from the stack?

¡Hot water at 50°C is routed from one building in which 4. it is generated to an adjoining building in which it is used for space heating. Transfer between the buildings 192 occurs in a steel pipe (k = 60 W/m K) of 100-mm 20outside diameter and 8-mm wall thickness. During the winter, representative environmental conditions involve air at T = -5°C and V = 3 m/s in cross flow odmover the pipe. to instrub 04 (a) If the cost of producing the hot water is $0.10 per kW h, what is the representative daily cost of heat loss from an uninsulated pipe to the air per meter of pipe length? The convection resistance associated with water flow in the pipe may be neglected. (b) Determine the savings associated with application of a 10-mm-thick coating of urethane insulation (k = 0.026 W/m K) to the outer surface of the pipe. bas 0

2 A wire of diameter D = 2 mm and uniform temperature T has an electrical resistance of 0.01 N/m and a current flow of 20 A. (a) What is the rate at which heat is dissipated per unit length of wire? What is the heat dissipation per unit volume within the wire? (b) If the wire is not insulated and is in ambient air and large surroundings for which T = Tsur = 20°C, what is the temperature T of the wire? The wire has an emissivity of 0.3, and the coefficient associated with heat transfer by natural convection may be approximated by an expression of the form, h = C[(T-T)/D]¹/4, where C = 1.25 W/m7/4.K5/4 (c) If the wire is coated with plastic insulation of 2-mm thickness and a thermal conductivity of 0.25 W/m.K, what are the inner and outer surface temperatures of the insulation? The insulation has an emissivity of 0.9, and the convection coefficient is given by the expression of part (b). Explore the effect of the insu- lation thickness on the surface temperatures. Note: 1. The metal wire…

On a day when wind is blowing over a lake (T(water) =20°C) at 5 m/s, which side of the air-water interface will be rate-limiting on the flux of Ethyl benzene (i.e. va or vw)?