Electrical Engineering

A medical equipment industry manufactures X-ray machines. The unit cost C (the cost in dollars to make each X-ray machine) depends on the number of machines made. If x  machines are made, then the unit cost is given by the function C(x)=0.6x^2-408x+76,064 .What is the minimum unit cost?

A medical equipment industry manufactures X-ray machines. The unit cost C (the cost in dollars to make each X-ray machine) depends on the number of machines made. If x machines are made, then the unit cost is given by the function C(x)=0.6x^2-408x+76,064 .What is the minimum unit cost? EXPERT ANSWER     then the unit …

A medical equipment industry manufactures X-ray machines. The unit cost C (the cost in dollars to make each X-ray machine) depends on the number of machines made. If x  machines are made, then the unit cost is given by the function C(x)=0.6x^2-408x+76,064 .What is the minimum unit cost? Read More »

A plane wall with surface temperature 350C is attached with straight rectangular fins( k =235 W/m K). The fins are exposed to an ambient air condition of 25C and the convection heat transfer coefficient is 154 W/m2. Each fin has a length of 50mm, a base of 5 mm thick and a width of 100mm. For a Single fin, using a uniform nodal spacing of 10 mm, determine (a) the finite difference equations, (b) the nodal temperatures by solving the finite difference equations, and (c) the heat transfer rate and compare the result with analytical solution.

A plane wall with surface temperature 350C is attached with straight rectangular fins( k =235 W/m K). The fins are exposed to an ambient air condition of 25C and the convection heat transfer coefficient is 154 W/m2. Each fin has a length of 50mm, a base of 5 mm thick and a width of 100mm. …

A plane wall with surface temperature 350C is attached with straight rectangular fins( k =235 W/m K). The fins are exposed to an ambient air condition of 25C and the convection heat transfer coefficient is 154 W/m2. Each fin has a length of 50mm, a base of 5 mm thick and a width of 100mm. For a Single fin, using a uniform nodal spacing of 10 mm, determine (a) the finite difference equations, (b) the nodal temperatures by solving the finite difference equations, and (c) the heat transfer rate and compare the result with analytical solution. Read More »

Select the lightest column section for column AB in the frame shown. The column is under an ultimate load of 700k and only in-plane behavior is considered. Furthermore, assume that the column immediately above or below AB are the same size as AB. All beams are of W18x40 sections. Fy =50ksi . Assume: Inelastic Behavior. Assume any appropriate assumption

EXPERT ANSWER 1. Here it is given thatUse W14×61Fy = 50ksiNow, design strength of column AB Pu = 2658.45kDesign Strength of column AB = 2658.45k2. Let us first design column AB and then Base plate design must be doneAssuming both ends fixed. The effective length is 0.65×16 10.4 feet.Using LRFD, the factored load is Pu=1.2×350+1.6×450=1,140kips  …

Select the lightest column section for column AB in the frame shown. The column is under an ultimate load of 700k and only in-plane behavior is considered. Furthermore, assume that the column immediately above or below AB are the same size as AB. All beams are of W18x40 sections. Fy =50ksi . Assume: Inelastic Behavior. Assume any appropriate assumption Read More »

A type 1-1 shell-tube condenser condenses 5000 kg/h of saturated ethanol vapor at normal pressure with cooling water at 25°C. Liquid ethanol exits the apparatus at a temperature of 600°C. The water leaving the device has a temperature of 400C. Let the heat coefficient of steam side is 6000W/m2.K, liquid ethanol side is 3000W/m2K, water side is 2000W/m2K. Let’s: a) Draw device diagram, line symbol b) Calculate the heat transfer coefficient of the device. c) Calculate the amount of water needed to cool down d) Calculate the number of pipes 21x2mm if L= 50 is selected.

EXPERT ANSWER

Two blocks of mass m1 = 2.00 kg and m2 = 6.00 kg on a frictionless table are connected by a massless string. Forces of magnitude F1 = 10.0N and F2 = 5.00N are applied as shown. The string remains taught during the motion. (a) Draw a free body diagram for each block. (b) Draw a free body diagram for the blocks and string treated as one system. (c) What is the acceleration of the blocks? (d) What is the tension in the string?(e) What are the normal forces exerted by the table on each block? (f) What is the net force (direction and magnitude) acting on m2

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The standard FM broadcast band has a frequency range of 88 – 108 MHz. Stations are spaced every 200 kHz beginning at 88.1 MHz and up to 107.9 MHz. The maximum permitted deviation is 75 kHz, with modulating frequencies up to 15 kHz. Compute the bandwidth of an FM station using two methods and then discuss how the bandwidth compares with the channel spacing.

EXPERT ANSWER The two methods to compute the bandwidth of an FM station are by using the modulation index and by using the Carson’s rule. 1) The formula for bandwidth calculation using modulation index is given as where, N is the number of significant sidebands, and fm is the highest modulating frequency Assuming a modulation index …

The standard FM broadcast band has a frequency range of 88 – 108 MHz. Stations are spaced every 200 kHz beginning at 88.1 MHz and up to 107.9 MHz. The maximum permitted deviation is 75 kHz, with modulating frequencies up to 15 kHz. Compute the bandwidth of an FM station using two methods and then discuss how the bandwidth compares with the channel spacing. Read More »