MICROBIOLOGICAL ENGINEERING - QUESTION 28.2 : A hemocytometer is a device that is used for counting cells. In an engineering experiment, 100 microlitres of cell suspension is diluted with 50 microlitres of Trypan blue dye. Only death cells appear blue in color when stained with the dye. There are 57 cells detected in a hemocytometer, where 5.3 % of them appear blue when the chamber of the meter is placed under a microscope. Each square of a chamber can contain 0.0001 mL of liquid. (a) Calculate the number of viable cells. (b) The cells occupied 5 squares. Calculate the average number of viable cells / square. (c) Calculate the dilution factor of the cell suspension by using the formula : Dilution = final volume / initial volume. (d) Calculate the concentration of viable cells / mL by using the formula : Concentration = (Average number of viable cells / square) x dilution x (square / volume).
MICROBIOLOGICAL ENGINEERING - ANSWER 28.2 : (a) Number of death cells = Total cells x % of death cells / 100 = 57 x 5.3 / 100 = 3.021 rounded to 3 cells. Number of viable cells = Total cells - number of death cells = 57 - 3 = 54 cells. (b) Average number of viable cells / square = 54 / 5 = 10.8 cells / square. (c) Dilution = final volume / initial volume = (100 + 50) microlitres / 100 microlitres = 1.5. (d) Concentration = (Average number of viable cells / square) x dilution x (square / volume) = 10.8 cells x 1.5 x (1 / 0.0001 mL) = 162000 cells / mL. 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.
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In a Furnace arch pressure is more than Hearth pressure,then how flue gas travels to stack
POLYMER ENGINEERING - QUESTION 24.2 : Let C% be the fractional crystallinity, Rs = density of sample, Ra = density of amorphous form and Rc = density of crystalline form. In a polymer, these unknowns could be related by the equation C% = (Rc / Rs) (Rs - Ra) / (Rc - Ra). (a) Find the equation of Rc as a function of C%, Rs and Ra. (b) Two samples of a polymer, C and D exist. For sample C, C% = 0.513 when Rs = 2.215 unit. For sample D, C% = 0.742 when Rs = 2.144 unit. Both samples C and D have the same values of Ra and Rc. Find the values of Ra and Rc in 6 decimal places.
Are there any methods of preventing cracking of carbon steel welds in refining environments?
ACCOUNTING AND FINANCIAL ENGINEERING - EXAMPLE 34.36 : Du Pont analysis is used to perform calculation on Return On Equity (ROE) for an engineering organization. Let Net Income = A; Earning Before Tax (EBT) = B; Earning Before Interest, Tax (EBIT) = C; Sales = D; Assets = E; Equity = F. In 5-step Du Pont formula, let Tax Burden = G = A / B; Interest Burden = H = B / C = 1.04; EBIT % = I = C / D = 0.27; Asset Turnover = J = D / E = 0.66; Leverage = K = E / F = 2.66; ROE = L = A / F. If (1 / G) = (4 / 3) : (a) find the value of L; (b) calculate the values of A, B, C, E and F when D = $1500; (c) verify the answer (b) is correct by using the answer (a).
What is the best way to control an oversized, horizontally oriented shell and tube steam heater?
What is maximum recommend pipe velocity for dry and wet gases?
CHEMICAL ENERGY BALANCE - EXAMPLE 11.2 : Calculate the cooling duty, H required to condense and cool acetone from 100 degree Celsius to 25 degree Celsius at atmospheric pressure. The heat of vaporization for acetone at its normal boiling point is 30.2 kJ / mol. The boiling point of acetone at atmospheric pressure is 56 degree Celsius. The flowrate of acetone through the condenser is 100 mol / s = N. Value of sensible heat needed to increase the temperature of acetone in liquid form from 25 to 56 degree Celsius is 4.06 kJ / mol. Value of sensible heat needed to increase the temperature of acetone in vapor form from 56 to 100 degree Celsius is 3.82 kJ / mol. Unit of H is kJ / s.
ACCOUNTING AND FINANCIAL ENGINEERING - EXAMPLE 34.3 : (a) In the M / M / 1 queue that happens with randomness, let State 0 = the queue and server are empty, State 1 = the server is in use and the queue is empty, State 2 = the server is in use and 1 is in the queue, State 3 = the server is in use and 2 in the queue. Let P (0) = probability of State 0, P (1) = probability of State 1, P (2) = probability of State 2, P (3) = probability of State 3 and so on. If c = constant, P (1) = c P (0), P (2) = c [ c P (0) ], P (3) = c { c [ c P (0) ] }, write an equation that involves P (N), P (N + 1) and c. (b) Let L = market price of risk, r = riskless rate, m = expected return, s = volatility. Given that L = (m - r) / s related to oil prices, expected return = 12 %, s = 20 %, riskless rate = 8 %, calculate the market price of risk.
Given, T1=600C, constant temperature of wall 800 , length of wit exchanger L=3m, dia=25 mm, Cp=14.91 KJ/kg.K, density ρ=914 kg/m3,mean velocity vm= 2 m/s, film heat transfer coefficient hf=72 Kcal/h.m2.K, what is the outlet temperature?
Question 81 - (a) In natural gas pipe sizing, the length of the pipe from the gas source metre to the farthest appliances is 60 feet. The maximum capacities for typical metallic pipes of 60 feet in length are : 66 cubic feet per hour for pipe size of 0.5 inches; 138 cubic feet per hour for pipe size of 0.75 inches; 260 cubic feet per hour for pipe size of 1 inch. By using the longest run method : (i) Find the best pipe size needed for the capacity of 75 cubic feet per hour. (ii) Estimate the suitable range of capacities for the pipe size of 1 inch. (b) The maximum capacities for typical metallic pipes of 50 feet in length are : 73 cubic feet per hour for pipe size of 0.5 inches; 151 cubic feet per hour for pipe size of 0.75 inches; 285 cubic feet per hour for pipe size of 1 inch. By using the branch method find the best pipe size needed for the capacity of 75 cubic feet per hour when the length of the pipe from the gas source metre to the appliance is 52 feet.
How can metals be removed from aqueous waste streams?
What is the largest application for surfactants?
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