3.34 Design a logic circuit that has five input variables and one output variable. Four of the input variables represent BCD digits, and the fifth is a control line. While the control line is at logic 0, the output should be logic 1 only if the BCD digit is greater than or equal to 5. While the control line is high, the output should be logic 1 only if the BCD digit is less than or equal to 5.

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