III B.Tech I Semester Regular Examinations,Nov/Dec 2009 Material Scinece for Chemical Engineers Chemical Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. Discuss on the following:
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(a) Properties of dislocations (b) Zero-dimensional imperfections.
[8+8]
2. Discuss the invariant reactions involved in the following binary systems: (a) Fe-Fe3 C (c) Cu-Ni.
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(b) Pb-Sn
[6+5+5]
3. (a) Explain with examples, how dipole attractions result in a profound alteration of physical properties.
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(b) Explain the nature of bonds which are partially covalent and partially ionic. [10+6] 4. (a) Discuss the three most common metal crystal structures. (b) What is diamond cubic structure? Draw the unit cell. What is the space lattice and coordination number of a diamond cubic crystal? [8+8] 5. (a) Discuss the hardness and strength features of Fe-C martensites.
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(b) Discuss the advantages and disadvantages of austempering process in plain carbon steels. (c) What are low-alloy steels? Write their engineering applications.
[6+6+4]
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6. (a) Pit corrosion punctured the hull of an aluminum boat after 12 months in sea water. The aluminum sheet was 1..1 mm thick. The average diameter of the hole was 0.2 mm. i. How many atoms were removed from the pit per second? ii. What was the corrosion current density?
(b) Explain what concentration cells are.
[6+10]
7. (a) Explain the reason why real crystals deform at a much lower stress than predicted by the model for a perfect crystal. (b) Discuss how quenching and tempering processes modify the structure and properties of steels. [8+8]
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Code No: 45016
R07
Set No - 1
8. (a) What is tempered glass? Explain the advantages of using it. (b) Explain the conditions that are sufficient for crack propagation in brittle materials. (c) Explain how the yield stress σy is a function of grain size.
[6+5+5]
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2
Code No: 45016
R07
Set No - 2
1. (a) Explain how grain boundaries are formed?
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III B.Tech I Semester Regular Examinations,Nov/Dec 2009 Material Scinece for Chemical Engineers Chemical Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ?????
(b) Discuss the properties of dislocations in terms of energy associated with them.
[5+5+6]
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(c) Write briefly on the substitutional and interstitial impurities.
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i. 10−5 sec−1 ii. 10−3 sec−1
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2. (a) The temperature and the strain rate dependence of yield stress in kg/mm2 for molybdenum is given by + 6.25 log10 dε σy = 2.1 + 17700 T dt in sec−1 . Cracks Where T is the absolute temperature and the strain rate dε dt of length 2µm are also present in the material. Estimate the temperature at which the ductile to brittle transition occurs in this material at a strain rate of:
Young’s modulus = 35 × 1010 Pa and the specific surface energy = 2 J/m2 (b) Give a brief account on the various stages of creep rate with reference to design considerations for machine components. [8+8] 3. Which crystal structures are most commonly found in metals? Compare their packing efficiencies in terms of coordination number and atomic packing factor. [16]
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4. (a) Discuss the nature of bonds in diamond. (b) Summarize the secondary type of bonds and their characteristics.
[8+8]
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5. (a) Discuss the properties and microstructure of the following constituents of carbon steel: i. ii. iii. iv.
Austenite Pearlite Bainite Martensite.
(b) Write a brief note on the alloys and metals used in chemical industry. [8+8]
6. (a) With the help of an example explain how to determine the fractions of two co-existing phases. (b) Distinguish between Tie-line rule and lever rule. 3
[8+8]
Code No: 45016
R07
Set No - 2
7. (a) A mild steel cylindrical tank of 1 m height and 50 cm diameter contains aerated water up to 60 cm level and shows a loss in weight due to corrosion of 304 g after 6 weeks. Calculate: i. The corrosion current ii. The current density involved in the corrosion of tank
(b) Explain very briefly different types of corrosion.
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Assume uniform corrosion on the tank’s inner surface and that the steel corrodes in the same manner as pure iron. [8+8]
(a) Heated to 8750 , held there for 1 hr (b) Quenched to 2500 , held there for 2 sec (c) Quenched to 200 , held there for 100 sec (e) Quenched to 200 and held.
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(d) Reheated to 5500 , held there for 1 hr
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8. A small wire of steel is subjected to the following treatments as successive steps:
Describe the phases or structures present after each step of heat treatment sequence. [16]
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Code No: 45016
R07
Set No - 3
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III B.Tech I Semester Regular Examinations,Nov/Dec 2009 Material Scinece for Chemical Engineers Chemical Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. Discuss the following:
2. (a) A 0.8% C eutectoid plain-carbon steel is lowly cooled from 750 0 C to a temperature just slightly below 723 0 C. Assuming that the austenite is completely transformed to a ferrite and cementite i. Calculate the weight percent of eutectoid formed ii. Calculate the weight percent of cementite formed.
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(b) Discuss the features of annealing in producing pearlite, in eutectoid steels. [10+6] 3. (a) Discuss how ligancy rules determine the local packing around a cation, during the formation of ionic crystal, with the help of an example. (b) Define coordination number for an ionic crytsal. Predict the coordination number for the ionic solids CsCl and NaCl. Use the following ionic radii for the prediction: Cs+ = 0.170 nm Na+ = 0.102 nm Cl− = 0.181 nm [10+6]
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4. (a) How can the high electrical and thermal conductivities of metals be explained by the “electron gas” model of metallic bonding? (b) Explain molecular bonds, with examples.
[8+8]
5. (a) Discuss the elastic an anelatsic behavior of materials.
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(b) Summurize the different steel treating processes.
[6+10]
6. (a) Explain about the non-planar type of imperfections in a crystal. (b) Using sketches, show how two edge dislocations on the same slip plane with Burgers vectors of equal magnitude can come together and annihilate each other. [8+8]
7. (a) A 1 cm2 , 0.75 mm thick sample of 99.9 wt % Ni is oxidized in oxygen at 1 atm pressure at 500 0 C. After 5 hr the sample showed a 40 µg/cm2 weight gain. If the oxidation process follows parabolic behavior, what will be the weight gain after 15 hr of oxidation? 5
Code No: 45016
R07
Set No - 3
(b) Discuss: i. Activation polarization ii. Concentration polarization.
[6+10]
8. With the help of an examples, indicate and explain various phase regions in the following phase diagrams:
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(a) Unary diagram
[16]
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(b) Binary diagram.
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Code No: 45016
R07
Set No - 4
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III B.Tech I Semester Regular Examinations,Nov/Dec 2009 Material Scinece for Chemical Engineers Chemical Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. Write a note on the following: Equilibrium phase diagram Degrees of freedom Phase rule Invariant reactions.
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(a) (b) (c) (d)
[4+4+4+4]
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2. (a) Discuss on the similarities and differences between edge and screw dislocations. (b) Write briefly on Frenkel and Schottky defects. [8+8] 3. (a) Explain the mechanism of creep and the methods to increase creep resistance in materials. (b) Explain how the composite materials are superior interms of properties and applications. [8+8]
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4. (a) Explain the principal mechanisms where primary recrystallization can occur? (b) Discuss the factors which affect recrystallization process in metals. [8+8] 5. (a) Discuss how corrosion can be reduced by bringing environmental changes. (b) Explain half-cell reactions. [10+6]
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6. (a) How do you explain the formation of covalent bonds between neutral atoms? Account for the fact that inert gas elements do not usually for chemical bonds. Explain how the metallic bond differs from truly covalent and ionic bonds. (b) Discuss the approaches which lead to the explanation of covalent bonding. [10+6]
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7. (a) Discuss the reasons of high hardness and strength in Fe-C martensites of plaincarbon steels when their carbon content is high. (b) How does TTT diagram for a hypoeutectoid plain carbon steel differ from that of a eutectoid one? Discuss. [8+8] 8. What are the closest packed directions in the following: (a) The FCC structure (b) The HCP structure.
Young's modulus = 35 Ã 1010 Pa and the specific surface energy = 2 J/m2 · (b) Give a brief account on the various stages of creep rate with reference to design.
2. (a) Explain why hardening by quenching is followed by tempering. (b) Only mechanical properties not physical properties can be altered by heat · treatment.
All Questions carry equal marks · ***** · 1. Explain the microbial production of aminoacids with one example. [16] · 2. What are biofuels? How these are produced ...
1. Explain tree based indexing and hash based indexing techniques. [16] · 2. Explain the .... 1. Explain in detail the structure of B+ tree with an example · [16].
Describe the methods of manipulating DNA for gene cloning purpose. [16] · 5. What are transposons? and describe about the types of bacterial transposons. [16].
what do you understand by Lubrication of Joints? [16] · 5. (a) Explain the three features of viscoelasticity in detail · (b) Explain the working principle of oscillating ...
Perform a Chi-square test at .o5 level whether there is a significance difference ... (b) Derive formulae to find the mean and variance of the Binomial distribution.
and T1 = sink temperature) for a Carnot refrigerator whose COP is 5. Also ... fusible plug, at what temperature should the plug melt to limit the maximum.
[8+8] · 7. (a) List out equipments used in pathology and blood bank departments of a · hospital. (b) Discuss about various blood groups present in humanbeings.
medical equipment. (b) Write a note on responsibilities of BME Department. [8+8] · 8. Discuss the sanitation procedures and laundry services with in a hospital.
Define and derive the equation for the vorticity of a flow. Hence prove that ... out from the leading edge to the trailing edge of a symmetrical airfoil. (b) State and ...
Check whether the following impedance functions are LC, RL or RC? (a) Z(s) = ... amplitude 5 V. Find autocorrelation function and energy spectral density. [8+8].
3. Regeneration is possible in the fixed-bias transistor flip-flop if the base-to-base · voltage gain exceeds unity. Verify that this gain condition is satisfied provided ...
Set No - 2. (b) Write about bus structures. ... (b) Explain time-shared common bus in detail. [8+8] ... (c) Asynchronous serial transmission with one stop bits · [16].
Consider a telegraph source having two symbols, dot and dash. The dot duration · is 0.2s.The dash duration is 3 times the dot duration. the probability of the dots.
(a) Explain how one can test for homogeneous catalyzed reaction using integral · method of Analysis. (b) An ampoule of radioactive Kr- 89 (half life = 76 minutes ) ...
(c) Cell Suspension cultures. ... 6. Explain the process of producing secondary metabolites in culture. ... (a) Discuss the importance of plant tissue culture in India.
3. Effect of radiation on Bone Marrow. (a) Describe the ... (b) Write short notes on artificial respiration. [8+8] ... (b) Write a note on Meta static bone diseases. [8+8].
(a) Explain the terms : Compilers, Linkers, Loaders, Assemblers. (b) Describe the program execution in a system with a neat diagram. [8+8] · 4. (a) Explain Read ...
(c) Explain why XML uses both streaming and tree-based parsing. [4+7+5] · 2. Explain the functionality of javax.servlet package for web servers. Discuss about.
of the offset point D on the coupler AB, and the angular velocities of links OA and ... lengths AB : OO1 : OA :: 1 : 2 : 2.5 for the point P to move in an approximate.
