Engineering Materials Research Paper
I would like to write a paper of the use of an InGaAs (Indium gallium arsenide) detector and how
we will incorporate it into our present seeker that we use. This would greatly enhance our
current capabilities on the se
SWIR Sensor Evaluation
13 December 2010
Page 1 of 23
This paper looks at a possible upgrade for an imagery detector that will enhance our
Engineering Materials Week 11-Interacvtivity
16.1 Cite the general difference in strengthening mechanism between large-particle and
dispersion-strengthened particle-reinforced composites.
The major difference is that for large-particle the particle matrix
Engineering Materials Week 11
16.5 Cite one similarity and two differences between precipitation hardening and dispersion
The similarity between precipitation hardening and dispersion strengthening is the strengthening
mechanism. The two differ
Engineering Materials Week 7
10.4 (a) For the solidification of nickel, calculate the critical radius r* and the activation free
energy G* if nucleation is homogeneous. Values for the latent heat of fusion and surface free
energy are -2.53 X10 J/m3 and 0.
Engineering Materials Week 10- Interactivity
14.1 Differentiate between polymorphism (see Chapter 3) and isomerism.
Polymorphism is when two or more crystal structures are possible for a material of given
composition. Isomerism is when two or more polymer
Engineering Materials Week 9-Interactvivty
12.1 Question: Table 12.3 gives the ionic radii for and as 0.138 and 0.140 nm, respectively.
(a) What would be the coordination number for each ion?
From Table 12.2 the coordination number for oxygen is 8.
Engineering Materials Week 10
14.4 (a) Compute the repeat molecular weight of polypropylene.
(b) Compute the number average molecular weight for a polypropylene for which the degree of
polymerization is 15,000.
14.10 Using the definitions for total chain
Engineering Materials Week 9
12.11 Iron titanate forms in the ilmenite crystal structure that consists of an HCP arrangement of
(a). Which type of interstitial site will the ions occupy? Why?
Since this ratio is between 0.414 and 0.732, the ions wil
Engineering Materials Week 6
9.7 Given here are the solidus and liquidus temperatures for the copper-gold system. Construct
the phase diagram for this system and label each region.
9.22 For 5.7 kg of a magnesium-lead alloy of composition 50 wt% Pb-50 wt%
Engineering Materials Week 8-Interactvity
11.1 Briefly explain why ferritic and austenitic stainless steels are not heat treatable.
Answer: Ferritic and austenitic stainless steels are not heat treatable since "heat treatable" is
taken to mean that marten
Engineering Materials Week 8
11.5 On the basis of microstructure, briefly explain why gray iron is brittle and weak in tension.
Gray iron is weak and brittle in tension because the tips of the graphite flakes act as points of
Engineering Materials Week 7-Interactivity
10.1 Question: Which is the more stable, the pearlitic or the spheroiditic microstructure? Why?
Spheroiditic microstructures are more stable than pearlitic ones because pearlite transforms to
Engineering Materials Week 6-Interactivity
9.1 What is the difference between the states of phase equilibrium and metastability?
Answer: For the condition of phase equilibrium the system is completely stable meaning that
over time the phase characteristic
Engineering Materials Week 5
8.9 Calculate the maximum internal crack length allowable for a Ti-6Al-4V titanium alloy
component that is loaded to a stress one-half of its yield strength. Assume that the value of Y is
8.23 Cite five factors that may
Engineering Materials Week 5-Interactivity
8.1 Cite two situations in which the possibility of failure is part of the design of a component or
Answer: (1) A pressure relief valve is designed to release pressure before the pressure builds
Engineering Materials Week 3
5.1 Briefly explain the difference between self-diffusion and interdiffusion.
Self-diffusion refers to movement of atoms within a pure material; interdiffusion refers to the
movement of one or more kind of atoms in a heterogen
Engineering Materials Week 4-Interactviity
7.1 Which of the following is the slip system for the simple cubic crystal structure? Why?
cfw_100 <110>, cfw_110 <110>, cfw_100 <010>, cfw_110 <111>
Answer: For simple cubic, the most densely packed atomic plane
Engineering Materials Week 3-Interactvivty
5.1 Rank the magnitudes of the diffusion coefficients from greatest to least for the following
N in Fe at 700C, Cr in Fe at 700C, N in Fe at 900C, Cr in Fe at 900C
Now justify this ranking. (Note: Both F
Engineering Materials Week 4
7.2 Consider two edge dislocations of opposite sign and having slip planes that are separated
by several atomic distances. Briefly describe the defect that results when these two dislocations
become aligned with each other.
Engineering Materials Week 2-Interactivity
3.1 What is the difference between crystal structure and crystal system?
A crystal structure is described by both the geometry and atomic arrangements within cell,
whereas a crystal system is described only in te
Engineering Materials Week 2
3.1 What is the difference between atomic structure and crystal structure?
Atomic structure relates to the number of protons and neutrons in the nucleus of an atom.
Crystal structure pertains to the arrangement of atoms in the
Engineering Materials Week 1
2.4(a) Cite two important quantum-mechanical concepts associated with the Bohr model of the
Two important quantum-mechanical concepts associated with the Bohr model of the atom are that
electrons are particles moving in
Engineering Materials Week 1- Interactivity
2.1- Why are the atomic weights of the elements generally not integers?
The atomic weights of the elements ordinarily are not integers because:
(1) the atomic masses of the atoms normally are not integers (excep
a. Indium gallium arsenide (InGaAs) is a semiconductor composed of indium,
gallium and arsenic. It is used in high-power and high-frequency
electronics because of its superior electron velocity with respect to the
more common semiconductor
Engineering Materials Week 13-Interactivity
18.3 Which of ZnS and CdSe will have the larger band gap energy Eg. Cite reason(s) for your
Zinc sulfide will have a larger band gap energy than cadmium selenide. Both are II-VI
compounds, and Zn and S a
Engineering Materials Week 13
18.7 How does the electron structure of an isolated atom differ from that of a solid material?
For an isolated atom, there exist discrete electron energy states each state may be occupied by
two electrons, which must have opp
Engineering Materials Week 12
17.7 An electrochemical cell is constructed such that on one side a pure Zn electrode is I
contact with a solution containing ions at a concentration of M. The other cell half consists of a
pure Pb electrode immersed in a sol
Engineering Materials Week 12-Interactivity
17.4 (a) From the galvanic series cite three metals or alloys that may be used to galvanically
protect nickel in the active state.
Tin, lead and cast iron may be used.
(b) Sometimes galvanic corrosion is prevent