The rotating disk is a useful laboratory tool for measuring dissolution of solids. The relationship for the mass transfer coefficient is Sh= 0.62Re^0.5. Se^1/5 where Re= r^2ωrho/μ

where ω is the rotation speed and r is the disk radius. The length parameter in the Sherwood number is the radius. Consider a rotating disk with a 3.0 cm diameter, rotating at 250.0 rpm, with a solid dissolving into a liquid at 25.0°C with the properties of water. The diffusion coefficient of the dissolved solid in water is 2.00x10-9 m²/s, and the solubility of the solid in the liquid is 0.200 kg/m².

Required:
Determine the initial rate of dissolution in kg/s. The initial dissolution rate occurs when there is zero dissolved solid in solution.

What is the main objective of using reheat rankine cycle?

Determine the time of the day and month of the year at which the peak sensible cooling load occurs for a top floor, north-eastern corner room of an office building in durban for the following conditions: floor area: 8 x 8 x 3 m east and north walls: 115 mm face brick (outside), 20 mm air space, 115 mm ordinary brick (inside) with 15 mm plaster roof construction: suspended plasterboard ceiling, 450 mm air space, 150 mm concrete, 75mm screed, waterproofing no heat transfer across other surfaces window area 3x 1,5 m high in north wall only. ordinary glass with venetian blinds. lights and occupants : from 07: 00 to 18: 00 average light density: 25 w/m2 number of occupants : 5 seated, light office work room temperature 24°c

Acompressor compresses a gas, a pump compresses a liquid. for a given pressure ratio, why does it take more work to compress a gas in a compressor than a liquid in a pump? a)- for a given pressure ratio the average specific volume for a gas is much higher than the average specific volume for a liquid. b)- there is no difference. the only difference is the amount of heat generated (not work) c)- for a given pressure ratio the average volurge for a gas is much higher than the average volume for a liquid. d)-there is no difference