Answer / kangchuentat

ELECTRICAL TECHNOLOGY - ANSWER 16.1 : I = IS [ exp (nVD / VT) - 1 ] = 0.000000000001 [ exp (1.5 x 0.026 / 0.026) - 1 ] = 0.00000000000348 A. 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.

How can we derive power factor equation p=vi cos phi?

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why Torispherical heads are used in pressure vessels?

1 Answers   India Cements,

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Question 57 – There are 2 simultaneous equations : (A1) x + (B1) y = D1 and (A2) x + (B2) y = D2. (a) By using Excel program, find the values of x and y when A1 = 80, A2 = 150, B1 = 52, B2 = 100, D1 = 3.5 and D2 = 2.3. (b) Write the expression of Excel in the form of =MMULT(MINVERSE(W:X),Y:Z) in order to get the values of x and y. W, X, Y and Z may be A1, A2, B1, B2, D1 and D2.

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Question 49 - According to rules of thumb in chemical process design, consider the use of an expander for reducing the pressure of a gas when more than 20 horsepowers can be recovered. The theoretical adiabatic horsepower (THp) for expanding a gas could be estimated from the equation : THp = Q [ Ti / (8130a) ] [ 1 - (Po / Pi) ^ a ] where 3 ^ 3 is 3 power 3 or 27, Q is volumetric flowrate in standard cubic feet per minute, Ti is inlet temperature in degree Rankine, a = (k - 1) / k where k = Cp / Cv, Po and Pi are reference and systemic pressures respectively. (a) Assume Cp / Cv = 1.4, Po = 14.7 psia, (temperature in degree Rankine) = [ (temperature in degree Celsius) + 273.15 ] (9 / 5), nitrogen gas at Pi = 90 psia and 25 degree Celsius flowing at Q = 230 standard cubic feet per minute is to be vented to the atmosphere. According to rules of thumb, should an expander or a valve be used? (b) Find the outlet temperature To by using the equation To = Ti (Po / Pi) ^ a.

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ACCOUNTING AND FINANCIAL ENGINEERING - EXAMPLE 34.16 : An engineer would like to invest his money in a home, business and bond. The implicit interest payment frequency is monthly for home loans, quarterly for business loans; semi annually for bonds. A generalized mathematical formula to calculate I = interest rate equivalence is I = (1 + i / N) ^ N - 1 where i = annual interest rate, N = number of payment per year. (a) Calculate the value of N for : (i) home loans; (ii) business loans; (iii) bonds. (b) For i = 0.08, find the value of I for : (i) home loans; (ii) business loans; (iii) bonds.

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Why Packed Bed is not preffered in seperation process while Tray column is used in Industries predominatly??

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Define "good" cooling tower water?

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How can we identify a poisoned food if we are not able to sense it?? . .,(naturally by colour ,smell etc. . .)

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Are there any alternatives to scraping a shell and tube if a capacity increase will make the pressure drop across the exchanger too large?

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In Galvonised iron and stainsteel pipes, in which pipe friction losses will more and why ?

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Why cavitation is produced

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Explain under what circumstances are vortex flowmeters the most accurate?

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