Afreezer compartment is covered with a 2.0-mm-thick layer of frost at the time it malfunctions. if the compartment is in ambient air at 20ºc and a coefficient of1.8 w/m2 ·k characterizes heat transfer by natural convection from the exposed surface of the layer, estimate the time required to completely melt the frost. the frost may be assumed to have a mass density of 740 kg/m3 and a latent heat of fusion of 334 kj/kg. t= hours

When subject to a steady load (within elastic range) over a long period of time, what is the major difference in material behavoir between steel and plastic?

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

In a unit cell of fcc structure, indicate the position of one of the tetrahedral interstitial sites by plotting the corresponding tetrahedron. do the same for one of the octahedral interstitial sites (in a separate fcc unit cell). mark the positions of all the tetrahedral and octahedral interstitial sites in the unit cells. how many equivalent tetrahedral sites and how many equivalent octahedral sites are contained in a fcc unit cell, respectively. what is the coordination number for a tetrahedral site and what is the coordination number for an octahedral site?