**Unformatted text preview: **National Institute of Technology, Rourkela —— 769008 Mid— Semester Examination, 2012-13; B. Tech: 3rd Semester
Subject: Unit Operations in Ceramic Processing; Sub ID: CR-Zl l; Full Marks: 60
Duration 01' Examination: 2 hrs
Answer ALL Questions
Q.No All parts of a question should be answered at one place Why the value of ‘crushing efﬁciency’ lies in a low range? Deﬁne ‘sphericity‘ of a particle.
Deﬁne surface—volume mean diameter of particulate solid. State a few of the applications
where the knowledge of particle size distribution is important. Derive Rittingers 121Wa Kicks “0”" . 2+2+2+6 D vs law and Bond’s law from the generalized equation: rig?) = —K =12 Derive critical speed of a ball mill. What technical importance it holds? Try to explain the
consequences of the following cases from the production point of view. Case 1; the volume of
(grinding media + feed material) is half of the chamber-volume. Case 11; the volume of
(grinding media + feed material) is much more than half of the charnbel--Vo1ume _ Case 111;
the volume of (grinding media + feed material) is less than half ofthe Chamber—volume. 4+2+6 = 12 _l_ 3 How do you design various bin storages? Compare the operations of belt conveyors and
bucket elevators. Deﬁne ‘angle of repose’. Why the ‘angle of repose‘ is found to be less than
the ‘angle of internal friction"? 6+4+2 = 12 _.__J 4 What is the ‘Degree of Pore Saturation’ (DPS)? Illustrate with suitable ﬁgure ofthe different
consistency state while DPS value is increasing from ‘0’. Make a table to characterize
different consistency state. 2+6+4=12 What criteria should you look for a mixer to mix v1scous material? Deﬁne mixing index for
granular solid and paste. Derive the formula of ‘rate of mixing’. Describe brieﬂy the
construction and working of any mixer known to you. 2+2+2+6=12 ...

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