Mse 200

Front 1

For glassy materials, cooling is accompanied by:

Back 1

continuous specific volume decrease

Front 2

Viscosity is a measure of a glassy material's resistance to

Back 2

deform under shear stress

Front 3

Crystal structure of a perovskite material is

Back 3

ABX3

Front 4

Isomerism is best described as

Back 4

having the same chemical equation but different structure

Front 5

Glass-forming operations are performed at a temperature range

Back 5

between the softening point and working point

Front 6

Stress relaxation of the polymer is a result of

Back 6

thermally activated sliding of polymer molecules

Front 7

In crystalline ceramics, coordination number depends upon

Back 7

cation-anion radius ration

Front 8

The possible crystal structure of a ceramic containing Mg and O will be that of

Back 8

NaCl

Front 9

Flexural strength of a ceramic material is generally

Back 9

greater than the tensile fracture strength

Front 10

Larger volume fraction of the stiff and brittle fibers makes the composite

Back 10

more stiff and less ductile

Front 11

A composite is made of copper matrix with aligned tungsten fibers. The volume fraction of tungsten fibers (Ew=1 GPa) required to increase the modulus of the copper matrix (Ecu=0.1 GPa) in the fiber direction to 0.5 GPa is

Back 11

0.44

Front 12

An example of a particle reinforced composite is

Back 12

concrete and spheroidite

Front 13

When the load is applied to a continuous aligned fiber-reinforced composite in the direction of the fiber alignment, the fiber and the matrix are subject to

Back 13

same strain

Front 14

Modulus of a fiber-reinforced composite with continuous aligned fibers is at its maximum in the direction

Back 14

parallel to the fibers

Front 15

The load taken up by the fiber in a fiber-reinforced composite when loaded along the direction of the fibers is proportional to

Back 15

product of modulus and volume fraction of the fibers

Front 16

When the load is applied to a fiber-reinforced composite in the transverse direction (normal to the direction of the fiber alignment) the fiber and matrix are subjected to

Back 16

same stress

Front 17

Crack bridging by fibers refers to

Back 17

fibers not allowing the crack surfaces to open up

Front 18

A small molecular weight byproduct usually forms in the following reaction

Back 18

condensation polymerization

Front 19

A Schottky defect is

Back 19

a cation vacancy and an anion vacancy

Front 20

The elastic behavior of the elastomers arises from

Back 20

stretching and aligning of the polymer chains

Front 21

The tendency to form a crystalline polymer increases with

Back 21

linear or one-dimensional polymerization

Front 22

The rigidity or the modulus of the polymer increases with

Back 22

cross-linking or branching

Front 23

As a polymer becomes more branched, the tendency to crystallize

Back 23

decreases

Front 24

Cross-linking in polymers

Back 24

increases the modulus

Front 25

A polymer fiber is stronger than the bulk polymer because

Back 25

the molecules are oriented along the fiber axis and strong covalent bonds support the load

Front 26

Larger amounts of initiator and terminator compound cause the degree of polymerization to

Back 26

decrease

Front 27

During addition polymerization, monomers are linked together by

Back 27

replacing a double bond with two single bonds

Front 28

The cross-linking in vulcanization of rubber (polyisoprene) is achieved through

Back 28

sulfur atoms

Front 29

A polyethylene sample is subjected at room temp (27 C) to a tensile stress of 50 psi. The stress relaxes to 25 psi after 5 minutes with the cross-heads held without movement. Calculate the stress 30 min after the sample was pulled in tension.

Back 29

0.78 psi

Front 30

Temp 27C, initial stress of 50 psi, relaxes to 25 psi after 5 min. Calculate relaxation modulus Er 30 min after the sample was pulled in tension if a measured strain is 0.4

Back 30

1.95 psi

Front 31

A Frenkel defect is

Back 31

when a cation is out of place

Front 32

As %Crystallinity increases

Back 32

TS and modulus INCREASE

Front 33

Annealing causes

Back 33

crystalline regions to grow, %crystallinity increase

Front 34

Thermoplastics

Back 34

have little cross-linking, are ductile, soften with heating

Front 35

With decreasing temp or increasing strain rate in thermoplastics

Back 35

modulus increases, TS increases, %EL decreases

Front 36

MMC (metals) are dispersed in composite materials to

Back 36

increase yield stress, TS, and creep resistance

Front 37

CMC (ceramics) are dispersed in composite materials to

Back 37

increase Kc (crack bridging), toughness

Front 38

PMC (polymers) are dispersed in composite materials to

Back 38

increase modulus, yield stress, TS, and creep resistance