Octane (C8H18) Is combusted with excess air. The product gas composition is partially known. The dry gas compositions of octane and carbon dioxide are: Octane mole fraction - 0.0062
Carbon dioxide mole fraction - 0.0455
What is the percent excess air fed to the combustor? Assume combustion is complete and use a basis of 100 mol/h of the dry gas (stream 4 below) for your calculations. Note the reaction below is not balanced. Report answer to three sig figs.
n3
yOce
1 Combustor W=
Oc+02 = CO2+W
ni
W = H20
Ốc -CEH18
0.21
0.79
n2
YO2=
yN2=
109
nd-
yoc
yCO2
YO2
YN2

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.