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Powder Metallurgy Mcqs

Q:

Which of the following criteria can be used for shape characterization?

A) Verbal expression and evaluation of bulk properties B) Shape factor
C) Verbal expression, shape factor, and evaluation of bulk properties D) Shape factor, shape generation, verbal expression, and bulk property evaluation
 
Answer & Explanation Answer: D) Shape factor, shape generation, verbal expression, and bulk property evaluation

Explanation: Shape characterization falls under 4 different classes. They are, (1) Verbal expression (spherical, elongated, irregular); (2) Use of dimensionless number (shape factor); (3) Shape generation using Fourier analysis, polynomial fitting, matrix mapping; (4) Evaluation of bulk properties.

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50
Q:

Particle shape can be defined as, “the recognized pattern of relationship between points that form the internal surface of the particle.”

A) True B) False
 
Answer & Explanation Answer: B) False

Explanation: Particle shape can be defined as, “the recognized pattern of relationship between points that form the external surface of the particle.” Particle shape analysis is a fundamental characteristic of powder particles, which influences other parameters like flow rate, apparent density, compressibility, and sinterability.

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63
Q:

Which of the following concepts are used to differentiate and describe particle shapes?

A) Dimensionality of particle B) Dimensionality and Surface contour
C) Surface contour of particle D) Dimensionality and atomic mass
 
Answer & Explanation Answer: B) Dimensionality and Surface contour

Explanation: Two different concepts used to differentiate and describe particle shapes are based on, (1) the dimensionality of the particle (1D, 2D, 3D), and (2) the surface contour of the particle.

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51
Q:

The laboratory methods for sizing by _________ can be divided into fractionating and non-fractionation groups.

A) Elutriation method B) Sedimentation method
C) Adsorption method D) Permeability method
 
Answer & Explanation Answer: B) Sedimentation method

Explanation: The laboratory methods for sizing by sedimentation can be divided into 2 groups: (1) The fractionating methods are employed when it is essential to separate individual size fractions for individual examinations. (2) Non-fractionation methods are used for determining size distribution and estimating specific surface.

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54
Q:

_______ establishes the relationship between the settling velocity of falling particles and particle size.

A) Hess law B) Continuity equation
C) Stoke’s law D) Bernoulli’s equation
 
Answer & Explanation Answer: C) Stoke’s law

Explanation: Stoke’s law establishes the relationship between the settling velocity of falling particles and particle size which states that the settling velocity of falling spherical particles at low velocity in a quiescent homogenous fluid of infinite extent is proportional to the square of the particle diameter.

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69
Q:

_______ is the statistical relation between amount and size.

A) Particle size distribution B) Cumulative weight retained
C) Particle size D) Packing density
 
Answer & Explanation Answer: A) Particle size distribution

Explanation: Particle size distribution is the statistical relation between amount and size. It is also of fundamental importance as it affects the pressing and sintering behavior as well as the physical and mechanical properties of the sintered material.

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50
Q:

The particle size measurement technique based on the settling velocity of particles in stationary fluid medium is called _____

A) Sedimentation Method B) Microscopic Method
C) Elutriation Method D) Permeability Method
 
Answer & Explanation Answer: A) Sedimentation Method

Explanation: Sedimentation method is based on the settling velocity of particles in stationary fluid medium whereas, elutriation differs from sedimentation in that the fluid is in motion in the upward direction against the falling particles. Microscopic method involves actual counting of particles. The permeability method involves measuring the pressure drop across the bed of packed powder particles contained in a chamber in relation to the fluid flow.

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67
Q:

Which of the following are the techniques for particle size measurement?

A) Macroscopic analysis B) Sieve analysis and Absorption method
C) Sieve analysis, microscopic analysis, sedimentation method, and permeability method D) Filtration method and Sieve analysis
 
Answer & Explanation Answer: C) Sieve analysis, microscopic analysis, sedimentation method, and permeability method

Explanation: There are 7 particle size measurement technique which are as follows: Sieving analysis, Microscopic analysis, Sedimentation method, Elutriation method, Permeability method, Adsorption method and Electrolytic Resistivity method.

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