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Sunday, 8 February 2015

Product design and manufacturing- Model question paper for B.E/B.Tech Mechanical Engineering

1(a) ‘Design is an iterative process’. Explain the statement in the light of Asimow’s model. (6 Marks)
(b) What is a product message? How are lightness, speed, stability conveyed in products? Illustrate through examples. (6 Marks)
(c) How is toughened glass pre-stressed to make it impact resistant and stronger in bending? (4 Marks)
(d) What is a balanced design? Why is the material of a worm wheel selected as brass while for a worm, steel is used? (4 Marks)
2(a) How provision of ribs increases the stiffness and strength of a plate? (4 Marks)
(b) What is a Michael stainfield? How is this concept utilized in designing a Nylon gear? (6 Marks)
(c) Differentiate between hot chamber and cold chamber die casting processes. (6 Marks)
(d) Explain the utility of Merchant’s circle diagram. (4 Marks)
3(a) Powder metallurgy can produce only prismatic shapes. How to achieve complex shapes by powder metallurgical process. (4 Marks)
(b) Why bosses are avoided in flat die forging? (4 Marks)
(c) Describe injection moulding and dipping method of production of rubber products. What is reaction injection moulding? (6 Marks)
(d) Write a note on special considerations for design of glass parts. (6 Marks)
4(a) What is a break-even chart? How does it help in arriving at profit or loss corresponding to a certain quantity of production? (5 Marks)
(b) How environmental factors such as noise can be taken care of to ensure worker efficiency? (4 Marks)
(c) How is ergonomics applied to displays and controls? Give a list of controls and displays used in ergonomics. (6 Marks)
(d) A strut is subjected to a tensile force of P 20 kN. The value of σt = 100 N/mm2. If the material cost is Rupees 30 per kilogram and the metal cutting cost per surface is Rupees 10 per mm2, calculate the section dimensions for cost minimization. The strut length is 800 mm. Assume the density of the material ρ = 8000 kg/m3. (5 Marks)
5(a) What is a value? Write a note on the value analysis job plan. (6 Marks)
(b) Mention the ground rules for creative techniques. (4 Marks)
(c) How is a multivariable chart used? How does it help in material-process selection? (4 Marks)
(d) Explain functional analysis system technique diagrams. Illustrate with an example. (6 Marks)
6(a) How is feasibility analysis facilitated using computer? (4 Marks)
(b) What is DBMS in computer integrated manufacturing? What is adaptive ability for a good database? (6 Marks)
(c) What is quality function deployment? (4 Marks)
(d) What is meant by rapid prototyping? What are different methods of rapid prototyping? (6 Marks)
7(a) Develop expression for reliability of systems in series and parallel. (6 Marks)
(b) What are chance causes of variation and assignable causes of variation in a process? What are trial control limits and stable control limits of a process. (4 Marks)
(c) What is fault tree analysis? Make a logic diagram for inability of an engine to start. (6 Marks)
(d) A computer has two CPUs working in parallel. The failure rate of a single CPU is 0.005 failures per hour. Calculate MTTF. (4 Marks)
8(a) What is the aim of business analysis? How is economic commercial value determined? (6 Marks)
(b) What is the role of critical path analysis in a launch project? (4 Marks)
(c) Compare the green score index of automobiles of the past and present. (4 Marks)
(d) How is a products stage determined in a product life cycle if the sales data in year 1 and year 2 is known and the standard deviation σ of the sales is known? If the sales of a product in year 1 are 400 and in year 2 is 370, predict the stage where the product is of standard deviation 40 units. (6 Marks)

Friday, 6 February 2015

Elements of heat and mass transfer- Model question paper for B.E/B.Tech Mechanical Engineering

1(a) Write a note on respiratory gas exchange in lungs (6 Marks)
(b) Differentiate between thermal conductivity and thermal diffusivity. (6 Marks)
(c) Explain why a quilt is a better insulator than a woolen blanket of the same thickness. (4 Marks)
(d) Identify the heat transfer processes that determine the temperature on the inside of a room on a hot summer day. (4 Marks)
2(a)What is Biot number? Explain its significance. (4 Marks)
(b) What are Fins? Explain in detail transfer of heat from pin-fins of constant cross-section. (8 Marks)
(c) Write a note on thermal sterilization of canned goods. (4 Marks)
(d) A 200 g slab of butter at 300 K is put in a refrigerator at 277K. It takes 120 minutes for the centre of the slab to reach 281K. How long would it take for the centre of the slab to reach 279K? (4 Marks)
3(a) Using a neat figure, explain nodal mesh. (6 Marks)
(b) Explain method of energy balance for an interior node. (8 Marks)
(c) A 4mm brass plate is initially at 00C. One side of the plate is suddenly brought to a temperature of 1000C, with the other side maintained at 00C. Develop a finite difference formulation for obtaining the temperature distribution across the plate for various times. (6 Marks)
4(a) What is transpiration cooling? Write a note on reduction of evaporative losses in liquid nitrogen flask by transpiration. (10 Marks)
(b) State and explain Reynolds transport theorem. (6 Marks)
(c) Find the rate of heat transfer from a spherical water tank of diameter 10m, when exposed to quiescent air at 200C, when its surface temperature is 350C. (4 Marks)
5 (a) With special relevance to velocity profile and temperature profile, explain heat transfer in Couette flow. (6 Marks)
(b) Deduce the governing equations for free convection flows. (6 Marks)
(c) Explain why the surface of a bridge always freezes faster than the surface of a road. (4 Marks)
(d) Saturated steam at 540C condenses on a 2cm diameter vertical tube of length 1m with the surface temperature of 400C. Determine the rate of condensation of stem assuming film condensation. (4 Marks)
6 (a) What is free molecular transfer? Explain. (6Marks)
(b) Explain Fick law. (4 Marks)
(c) A mixture of inert gases contains equal mass fractions of helium, argon and xenon. Determine the composition in terms of the mole fractions. (4 Marks)
(d) Calculate the fraction of gases remaining at the centre of a 1cm thick slab of steel after 10 hours of vacuum out-gassing treatment. Assume the initial distribution of gas in steel to be uniform and diffusivity to be 10-9 m2/s. (6 Marks)
7 (a) Write a note on absorption of gas by a falling film of liquid. (8 Marks)
(b) Consider a turbulent flow over a flat plate. Determine the percentage change in the mass transfer rate, if the Schmidt number is halved by (a) reducing the viscosity by a factor of two, or (b) doubling the binary diffusivity. (6 Marks)
(c) Sketch the temperature versus length curves for a counter-flow and a parallel-flow heat exchanger for the case when Cc = Ch. (6 Marks)
8(a) What is a blackbody? Calculate the total emission from a black surface in terms of intensity of radiation. (6 Marks)
(b) What is configuration factor? Explain the role of reciprocity relation in the evaluation of configuration factors. (6 Marks)
(c) An isothermal furnace with a small hole is used to calibrate radiometric devices. If the radiation intensity is to lie within 0.5% of the nominal, determine the allowable variation in the temperature of the furnace when it is operating at 300K. (4 Marks)
(d) Consider two concentric spheres, 25 and 50 mm in diameter. The outer surface of the inner sphere is a blackbody and is at 1000K, while the inner surface of the outer sphere is gray with emissivity of 0.8 and is at a temperature of 500K. Determine the radiative exchange between the two surfaces. (4 Marks)