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BIOCHEMICAL ENGINEERING INSTRUMENTATION - ANSWER 29.2 : (a) By fraction of concentration, [ settled chromatography medium volume (L) ] / [ slurry volume (L) ] = slurry concentration (%) / 100. Then [ slurry volume (L) ] = [ settled chromatography medium volume (L) ] / [ slurry concentration (%) / 100 ]. (b) By fraction of volume, [ sample volume to be processed (L) ] / [ chromatography medium volume (L) ] = sample volume in percent total volume (%) / 100. Then chromatography medium volume (L) = [ sample volume to be processed (L) ] / [ sample volume in percent of total column volume (%) / 100 ]. 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.

Question 68 – Biochemical Oxygen Demand (BOD) could be calculated using the formula BOD = (DOi - DOf) (Vb / Vs) where Vb = Volume of bottle in ml, Vs = Volume of sample in ml, DOi = Initial dissolved oxygen in mg / L, DOf = Final dissolved oxygen in mg / L. (a) By using a bottle of Vb = 300 ml with sample Vs = 30 ml, find the BOD if DOi = 8.8 mg / L and DOf = 5.9 mg / L. (b) By using a bottle Vb = 600 mL with sample Vs = 100 mL, find the BOD if DOi = 8.8 mg / L and DOf = 4.2 mg / L. (c) Find the average BOD = [ Answer of (a) Answer of (b) ] / 2. (d) If the BOD-5 test for (a) - (c) is run on a secondary effluent using a nitrification inhibitor, find the nitrogenous BOD (NBOD) = TBOD - CBOD. Let TBOD = 45 mg / L and CBOD = Answer of (c).

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DIFFERENTIAL EQUATIONS - EXAMPLE 20.2 : During the landing process of an airplane, the velocity is constant at v. (a) If the displacement of the plane is x at time t, find the differential equation that relates t, x and v. (b) The plane has 2 parts of wheels - the front and the back, separated by a distance L. The front part of the wheel touches the land first, that allows the straight body of the plane to form an angle T with the horizontal land. If the vertical distance between the back part of the wheel and the horizontal land is y, find the equation of y as a function of L and T. (c) Find the differential equation that relates dy as a function of dt, v and sin T. (d) Find the differential equation that consist of dy as a function of y, L, v and dt. (e) Find the equation of y as a function of v, L, t and C where C is a constant. (f) When t = 0, prove that y = exp C as the initial value of y.

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What is Vacuum? If pressure is less than that of atmospheric, can we call it vacuum? If so some places have less atmospheric pressures, can we call people living there are living in vacuum?

5 Answers   ISRO, TCS,

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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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Why is the freezer placed at the top in a refrigerator, why not at the bottom ?

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For what ration of Lengh/Dia. of tank (Jacketed tank), maximum heat transfer area is available?

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why sphericle shaped vessele used for storage of petrol?

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

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Explain what is a quick way to calculate frictional pressure drops in carbon steel pipe?

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ACCOUNTING AND FINANCIAL ENGINEERING - EXAMPLE 34.17 : In the engineering calculations of interest rate caused by inflation, General Inflation Effect and Fisher Effect may be considered. Let I = inflation rate, R = nominal interest rate, r = real interest rate. According to Fisher Effect, (1 + R) = (1 + r) (1 + I). According to General Inflation Effect, r = R - I. (a) If I = 0.1 for all effects, both the values of R and r in the Fisher Effect are the same as R and r in the General Inflation Effect, find the values of R and r. (b) If R has the same value caused by both General Inflation Effect and Fisher Effect, find the possible values of R, r and I in term of R etc.

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what is the purpose of capacitor? and capacitor load means what? how does it connect?

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what three specific job positions do u target from the company.

2 Answers   Amec Foster Wheeler, Chevron, Exxon Mobil, Petrochemicals, TCS, Texaco,

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