The following equation has been used to predict the melting temperature, tm, of a spherical particle of radius r:
(1-tm/tm, bulk) = (2/(\rhoslr))[\gammas-\gammal(\rhos /\rhol)] (4.8)here, tm, bulk is the bulk melting temperature, \rhos and \rhol are the densities of the solid and liquid phases, respectively; \gammas and \gammal are the surface tensions of the solid and liquid phases, respectively; and l is the latent heat of the material. according to the scaling law in equation 4.5: tm ~ tm, bulk(1-1/r), r is the radius in nanometer.(tm, bulk = 1336 k, \rhos = 1.84

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

Precipitation hardening can be achieved in many light alloys by a three-step heat treatment. what is carried out and what is the purpose at each step? why is such a treatment necessary based on the nucleation and growth theory of phase transformation. compare this treatment with tempering martensite for carbon steels (similarities and differences).

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)