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National Institute of Technology, Rourkela — 769008 End- Semester Examination, 2012-13; B. Tech: 3rd Semester Subject: Unit Operations in Ceramic Processing; Sub ID: CR-211; Full Marks: 75
Duration of Examination: 3 hrs Answer ALL Questions All parts of a question should be answered at one place Why ‘wet,grinding’ is favored over ‘dry grinding’? Mention the difference in the shaping
by ‘Jollying’ and ‘Jiggering’. Why washing is needed in cake ﬁltration? Instead of
fabricating solid extrudate you want to get hollow cylinder. How would you get that?
Correlate the ‘volume shrinkage’ with ‘linear shrinkage ‘for an isotropic drying. 5><3=15 Why ‘sieving’ is important in ceramic processing? How do characterize the granular solids? With a neat schematic explain the construction and operation of a primary
crusher. 2.5 + 2.5 + 5 = 10 Describe the main mechanisms employed in mixing. Depending on the increasing
consistency can you suggest choosing of different type of mixer in processing? 6+4= 10 Discuss the cake ﬁltration and cross-ﬁltration in brief. Why the rate of ﬁltration
decreases with the time in case of cake ﬁltration? 5+5 =10 With suitable schematic describe the operation of a non—mechanical classiﬁer. How
settling velocity helps in gravitational classiﬁcation? 5+5 =10 State the advantages and disadvantages of piston extruder and auger extruder. Describe
the ‘bird foot crack’ and ‘moon shaped’ crack’ as extrusion defect with remedies. 5+5 =10 List up the drying defects and try to explain those by differential shrinkage. With suitable
schematics correlate the fact of ‘constant rate period’ and ‘falling rate period’ in drying. 5+5 =10 ...
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- Fall '15