Starting with a context diagram, draw as many nested DFDs as you consider necessary to represent all the details of your times portal system described in the following narrative. You must draw at least a context and level-1 DFD. In drawing these diagrams, if you discover that the narrative is incomplete, make up reasonable explanations to complete the story.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false

Adouble-strand no. 60 roller chain is used to transmit power between a 13-tooth driving sprocket rotating at 300 rev/min and a 52-tooth driven sprocket. a) what is the allowable horsepower of this drive? b) estimate the center-to-center distance if the chain length is 82 pitches. c) estimate the torque and bending force on the driving shaft by the chain if the actual horsepower transmitted is 30 percent less than the corrected (allowable) power.

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented