PROCESS CONTROL - EXAMPLE 6.3 : The differential equation is 3 dy / dt + 2y = 1 with y(0) = 1. (a) The Laplace transformation, L for given terms are : L (dy / dt) = sY(s) - y(0), L(y) = Y(s), L(1) = 1 / s. Use such transformation to find Y(s). (b) The initial value theorem states that : When t approaches 0 for a function of y(t), it is equal to a function of sY(s) when s approaches infinity. Use the initial value theorem as a check to the answer found in part (a).

Answer Posted / kangchuentat

PROCESS CONTROL - ANSWER 6.3 : (a) For the equation 3 dy / dt + 2y = 1, its Laplace transformation is 3 [ sY(s) - y(0) ] + 2Y(s) = 1 / s, 3 (sY - 1) + 2Y = 1 / s, 3sY - 3 + 2Y = 1 / s, 3sY + 2Y = 1 / s + 3, Y (3s + 2) = (1 + 3s) / s. Y = Y(s) = (1 + 3s) / [ s (3s + 2) ]. (b) Initial value theorem states that y(0) = sY(infinity), then 1 = s (1 + 3s) / [ s (3s + 2) ] = (1 + 3s) / (3s + 2) approaches 1 when the value of s approaches infinity. The checking is correct. The answer is given by Kang Chuen Tat; PO Box 6263, Dandenong, Victoria VIC 3175, Australia; SMS +61405421706; chuentat@hotmail.com; http://kangchuentat.wordpress.com.

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

How can you estimate the efficiency of a pump?

737


What is a good method of steam tracing large vessels?

793


MY generator water cooler inlet line height - 11 mtr inlet water line height - 7 mtr water come into the line from overhead tank, O/H tank height - 20 mtr the first tapping in the inlet line is 2" line which down to 4 mtr level plateform., second tapping in inlet water line goes to a pump 6" line installed at 4 mtr level plateform, pump capacity 200m3/hr, head- 30 mtr, hp-40. the outlet of pump of 6" water line connected to a header of 6 mtr long of 6" line, on this header the six tapping are connected, 4 nos. 3" line goes to 11 mtr height water cooler the pressure of the line is 0.15 to 0.25 kg/cm2, 2" and 4" pipe line connected to a cooler at 4 mtrlevel plateform. my question is, at 11 mtr height level the quantity of water and flow is not sufficient for my cooler, the temp. of cooler is rises much more. you are requested to suggest the modification of pipe line/ pump for take more water flow and pressure (desired pressure is 1 kg/cm2)

1943


What is the difference between cfm (cubic feet per minute) and scfm (standard cubic feet per minute)?

833


what is first order of reaction?

1318






What is the import procurement cycle? What are the customization steps in sap?

607


What is screen analysis and what are its applications in the chemical industry?

749


Explain what is the significance of the minimum flow required by a pump?

802


How can you keep our seawater used for heat rejection clean before entering our heat exchangers?

769


how should i prepare for my placements.i am a student of chemical eng,final year,thapar university

1822


Explain what are some typical applications for glass-lined reactors?

725


What types of pneumatic conveying systems are typically used?

688


I would like to know how to size a partial combustion reactor processing methane and oxygen, as a function of the flowrate and of the pressure.

656


need the type of technical questions in written test

1699


How can one determine if a particular solid can be fluidized as in a fluidized bed?

713