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# 4th Semester Mechanical Engineering (2013-June) Question Papers

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## 4th Semester Mechanical Engineering (2013-June) Question Papers Document Transcript

• + T +t rvt f C rfUSN Time: 3 hrs. Fourth Semester B.E. Degree Examination, June/July 2013 If w: z3 find dddz. If the potential function is \$ = 16* 1OMAT4l Max. Maiks:100 (06 Marks) (07 Marks) . Find the stream function. (07 Marks) Engineering Mathematics - !V ,, I -oo I ij9p o. t* .Ed '-^ o- 6. FO. 5(E ;q- a3 U< -i .i o z E E PART - A I a. Use modified Euler's method to ,olre !l = * + y, y(0) = 1 at:-'x '= 0.1 for three iterations dx takingh:0.I. (06 Marks) dv 6. Solve l=*+y,x:O y=1 at x:0.2 using Runge-Kutta method' Take h:0.2." dx (07 Marks) c. Using Milne's predictor-corrector method furd y(0.3) correct to thLree decimals given, (07 Marks) Note: 1. Answer FIVE full questions, selecting dt leost TIVO questions from each part. 2. Use of Statistical tables permitted x -0.1 0 0.1 0.2 v 0.908783 1.0000 1.1 1 14s 1.25253 ^dv! 6. Approximate y and z at x : 0.? using Picard's method for the solution sf :l- = , , *=*'rr-., wirh y(0): l. z(0)- l/2. Perform two steps (yr. y2.:Zt.z2l. (l0Marks) dx Using Runge-Kutta meihod solve y" : x(y')' - f at x = 0.2 with xo - 0, y0 : 1, 26 : 0 take h : 0.2. ( l0 Marks) If (z) : u + iv is anall.tic prove that Cauchy-Reimann equations u1 = Vy, uy : -v* are true. b. b. C. 4 a. Find the bilinear transformation which maps the points z = I . i. - I onto the poinls * = j. o. -i. (06 Marks) b. Discuss the conformal transformation w: e'. Any horizontal strip of height 2n in.z-plane will map what portion of w-plane. c . State and prove Cauchy' s integral formula. (07 Marks) (07 Marks) (06 Marks) (07 Marks) (07 Marks) 6 PART- B { a. Prove that J'''=-ia sinx.t Vnx b. State and prove Rodrigues formula for Legendre's polynomials. c. Express f(x) : xa + 3xr - x2 + 5x - 2 in terms of Legendre polynomial. 2 +y 1of 2
• lOMAT4I 6 a. The probabilities offour persons A, B, C, D hitting targets are respectively 112, 113,114,1/5. What is the probability that target is hit by atleast one person if all hit simultaneously? (06 Marks) b. i) State addition law ofprobability for any two events A and B. iil Two different digits from 1 to 9 are selected. What is the probability that the sum of. the two selected digits is odd if '2' one ofthe digits selected. (07 Marks) c. Three machine A, B, C produce 50%, 30%, 20%o of the items. The percentage of defective items arc 3, 4,5 respectively. If the item selected is defective what is the probability that it is ritom machine A? Also find the total probability that an item is defective. 7a. Theliil.f of x is Find k. Also fildp(x > 5), p(3 < x < 6). (06 Marks) 6. A die is thrown Stiines. Find the probability that '3' falls, i.1 Exactly 2 times ii) At least once iii) At the most 7 times. (07 Marks) c. In a certain town the duration gf shower has mean 5 minutes. What is the probability that shower will last for i) 10 minutes or more; ii) less than l0minutes; iii) between 10 and 12 (07 Marks) minutes- What is null hypothesis, alternatiye hyliiithesis significance level? (06 Marks) The nine items of a sample havc the following values: 45, 47, 50, 52, 48, 47, 49, 53, 51. Does the mean ofthese differ'significantly from the assumed mean of47.5. Apply student's t-distribution at 5% level ofsignificance. (to os for 8df:2.31). (07 Marks) c. In experiments on a pea breading, the following frequencies of seeds were obtained: Round-yellciw Wrinkled yellow Round green Wrinkled green Total 315 101 108 32 556 8a. b. ls the experiment is in the agreement of theory which /- 9:3:3:1 (xjr,, 3df = 7.815). (07 Marks) predicts pioponion of fiequencies (07 Marks) x 0 1 2 J 4 5 6 p(x) k 3k 5k 7k 9k 11k 13k 2 of2
• USN IOI0/IF.4zAIAU42A Max. Marks:100 materials. (08 Marks) Calculate the hardness (06 Marks) (05 Marks) (10 Marks) (05 Marks) (05 Marks) Fourth Semester B.E. Degree Examination, June/July 2013 Material Science and Metallurgy Time: 3 hrs. Note: Answer FIVE full qaestions, selecting at least TWO questions from eoch part. 2 I *w) ;, I -ad q:; '-= -i ..i Z E PART _ A a. With neat sketch, explain body centered cubic face centered cubic and closed packed hexagonal structures with examples. (09 Marks) b. Derive expression for atomic packing factor of BCC, FCC and HCP structure. (07 Marks) c. Brielly explain the different tlpes ofpoint defects. (04 Marks) 2 a. With the help of stress-strain diagram,'explain the behaviour of ductile and brittle b. The lollowing data have been obtained in hardness test ofspecimens. number. Assume dia olball indenror: l0mm. Material Trt:e Load (kgf) Impression (mm) A Brinell 500 4.6 B Vicker's 5 0.28 c. Define the following terms Toughness, Resilience, Proofstress and ductility. (06 Marks) 3 a. With neat diagram, explain the fracture in the following: i) Ductile; ii) Brittle; iii) Fatigue. (12 Marks) b. Explain the three stages ofcreep with a neat sketch and its characteristics. (08 Marks) 4a. b. c. With neat diagram. explain the process olnucleation. d. Briefly explain the rules behind the solid solubility. b. What is level rule? Explain how it is useful. c. What are phase diagrams? How are they classified? Write a note on Gibb's phase rule with an example. (04 Marks) With the help of cooling curve. explain how soliditjcation process begins in pure metals. (06 Marks) (05 Marks) PART-B 5 a. Construct the Ag-Cu phase diagram using following data: Melting point of Ag : 960.5'C Melting point of Cu : 1085'C Eutectic point : 779.4oC Eutectic composition : 28.lYo Ctt Maximum solubility of Ag in Cu and Cu in Ag is 8%. Maximum solubility of Cu in Ag and Ag in Cu is 2%. Assume the liquidus, solidus and soh'us lines are straight. Calculate:' i) Amount of eutectic in 20%o Cu', 80% Ag alloy at 700oC and iD Percentages and compositions of solid phases in 60%o Ct and 40%o Ag alloy at 400'C. 1of2
• loIME4zAlAA42A 6 a. Draw Iron-Carbon equilibrium diagram and explain primary crystallization of steel hypoeutectic cast iron and hypereutectic cast iron. (10 Marks) b. Define the following annealing, normalizing, tempering, carburizing and nitriding. " (10 Mar[s) Y ' tY , a. How cast iron are classified? What are the properties of cast iron? (08 Marks) "-"tf),h. How generally steels are classified? Corsider at least two composition mixtures, q€_&ion its 'fJ, application and advantages. .. 'i{\$8 Marts) c.{p6p1ain the compositioq properties and uses of at least two copper based alloyi. (04 Marks) ul)* S a. Ddrffiqn expression for load distribution in a composite for longitrlSfirih. loading of fiber reinfdffi composite. (lo Marks) b. With;Hdpdagram, explain the hand laminating process. (10 Marks) lI '-t.i..' '"l,, .,-. r. {-Jt" r t! ,',.{, - -*) jb t I 4 , {r'1 - (r Y-' ^'.- l .!1.-r- ,,:' .'{ 2of2
• lOME/AU43 (10 Marks) I]SN Fourth Semester B.E. Degree Examination, June/July 2013 I g .!N ts ;! :Y -a ? .9. : -!l -i ..i a z E Applied Thermodynamics Time: 3 hrs. Max. Marks:100 Note:1. Answer FIVE full questions, selecting at least TWO questions from each port. 2, Use of thermodynomic data hand book is permitted. PART _ A 1 a. Explain the following: i) Enthalpy of formation ii) Conibustion efficiency iii) Enthalpy of combustion iv) Complete combustion v) Incomplete combustion (10 Marks) b. The products of combustion of hydrocarbon fuel of unknown composition have the following composition on dry basis: CO, : 8.0%. CO : 0.9 %, O: = 8.8 %,Nr:82.3% Calculate: i) Airfuel ratio ii) Composition of fuel on mass basis. iii) The percentage oftheoretical air on mass basis. (10 Marks) 2 a. Derive an expression of air standard efficiency of a dual cycle, stating the assumptions made. (10 Marks) b. A diesel engine operating on an air standard diesel cycle has 20 mm bore and 30 mm stroke. The clearance volume is 4.2x10-a m3. The fuel is injected for constant pressure for 5oh of the stroke, calculate the air standard efficiency. If the cut-off is delayed from 5% to 8%, what will be the effect on efficiencv? (10 Marks) a. Explain the following: i) Motoring test method ii) Willian's line method. (08 Marks) b. A two stroke diesel engine was motored when meter reading was 1.5 kW. Test on engine was carried lbr one hour and data observed were as follows: Brake torque = 120 N-m; Cp(gas) : 1 .05 kJ/kg-K, Speed : 600 rpm, Room temperaturc = 27"C, Fuel used : 2.5 kg, A : F ratio :32:1, Calorific value :40.3 MJlkg, Cooling water: 818 kg, Rise in temperature of cooling water: 10"C, Exhaust gas temperature - 347"C. Determine brake power, indicated power, brake thermal effrciency. And draw the heat balance sheet on minute basis. (12 Marks) 4 a. Sketch the flow diagram and corresponding T-S diagram ofa reheat vapour cycle and derive an expression for the reheat cycle efficiency. What are the advantages gained by reheating the steam in between stages? (10 Marks) b. A steam power station uses the fbllowing cycle: steam boiler outlet : 1 50 bar, 550'C Reheat at 0.1 bar, using the Mollier diagram and assuming the ideal process find, i) Quality of steam at turbine exhaust. ii) Cycle efficiency. I of2
• rOME/AU43 PART - B a. Derive an expression for minimum work I/P by two stage compressor with intercooler. (10 Marks) b. The following data refer to a single stage double acting air compressor in which air is drawn at 1 bar and compressor in which air is drawn at 1 bar and compressed to 16 bar, according to the law PVr25 =C. Input to compressor is 50 kW. The speed of the compressor is 300 rpm. The piston speed is 180 m/min. The volumetric efficiency is 8070. Calculate the diameter and stroke ofthe cvlinder. (10 Marks) a. With neat sketches, explain turbojet and ramjet propulsions. (10 Marks) b. A'gas turbine receives air at 100 kPa and 300 K and compresses it to 620 kPa. With compreqsor efficiency of 88%. The fuel has a heating value of 44180 kJ/kg and fuel air ratio is 0.017 kg of fuel per kg of air. The turbine efficiency is 90%. Calculate the compressor work, turbiiie work and thermal effrciency. (10 Marks) a. Explain the effect of super heating and sub-cooling with the aid of T-S and P-H diagrams. b' Explain steam jet re .geration. [8:ffi[:] c' A vapour compression refrigeration uses Freon-12, has its temperature - 1OoC and 30"C. The vapour enters the compressor dry and under cooled by 5"C in the condenser. For the capacity of I 5 TO R. find i) CoP ii.) Mass of Freon iii) Power required Cp (vapour.l : 0.56 kJ,&g-K and Cp lliquid) : 1.003 kJ,&g-K (t0 Marks) a. Define the following: ' - i ) Wet bulb temperature ii) Dew point temperature iii) Retative humidity iv) Specific humidity . v) Degree ofsaturdtion. b. A sling thermonieter reads 40'C DBT and 28'C WBT. Find the following: (10 Marks) (10 Marks) i) Specific humidity iii) Dew'point temperature ii) Relative humidity iv) Vapour density 2 of2