• Technical • Problem Definition • Social • Figure of Merit • Political • System Design • Economic • Constraints, Tradeoffs

• Statistics of Variation • Tolerance, Capability

3.003 Principles of Engineering Practice

Research Methodology (10min) The Ethical Engineer (30min)

Light-Matter Interactions (10min) Lionel C. Kimerling

Laboratory Methodology The Complete Engineer’s Skill Set

Technical—Social—Political--Economic

� Problem Definition � Constraints � Options � Analysis � Solution

3.003 Technology Problems The Complete Engineer’s Skill Set

Technical—Social—Political--Economic

Add the following to your lab report. � Problem Definition

� What problem is the team solving?

� Experiment Design � What are the constraints that the team

faces?

� Solution � Justify the experimental design?

�

�

3.003 Technology Problems The Complete Engineer’s Skill Set

Technical—Social—Political--Economic

� Problem Definition � Attributes, Specifications

� Design � Constraints

Figure of Merit: Tradeoffs

� Options � Analysis

Statistics of Variation: Tolerance, Capability

� Solution � Results

�

Figure of Merit materials selection

Materials DesignProperty relation to Performance

� Example: problem and constraint load bearing with lightest weight

� Volume = LxA � P = load

(1/m)max = Performance Materials Properties � tensile strength = σ = P/A=load/area� � m = density x volume = ρAL 1/m = σ/ρ x 1/PL

FOM =1/m= σ/ρ =tensile strength/density�

Ethical Practice

An Ethical Engineer?

� Conflicting motivations � divergence between commerce and

engineering? � is the data sufficient?

� Ethical action � most good for most people? � absolute right and wrong?

� Dealing at the boundaries

Laboratory Methodology The Complete Engineer’s Skill Set

Technical—Social—Political--Economic

� Problem Definition � Constraints � Options � Analysis � Solution

Ethics Basics

� Absolute of Judgment? � Rationale: good world or self? � Truth = ‘fuel of the mind’

� science of variation

� Can sustainability be built on fiction? � Ethics is not an act, but a lifetime; it is the

definition of self

The Puzzle of Moral Judgment

� Kant � Right is principles that everyone can follow.

� Mill � Right is the greatest good for the greatest

number of people.

Right before good or good before right?

Ethics: Private vs. Public

� Your purpose in life

� Your methods of achieving that purpose

Ethics: Private vs. Public

HYPOTHESIS OR FACT?

� The way that you live has consequences for the lives of others.

Light and Matter

Light is an Electromagnetic Wave

Courtesy of the Opensource Handbook of Nanoscience and Nanotechnology.

Observables

Photonic MaterialsElectromagnetic Field

� dielectric constant, ε/ε0� voltage � index of refraction, n

� current � absorption, α

� wavelength, λ

� group velocity, vg = co/N; N = group index � power, P

cmaterial = c0/nr nr= (ε/ε0)1/2

(static) n (υ)

Si 11.7 3.5

Ge 16 4

LiNbO3 43 2.27

BaTiO3 3600 2.46

c=speed of light; nr=refractive index; ε= electric permittivity ε/ε0=dielectric constant

Materials Design by Property Maps

CN = 8

CN = 6

CN = 4 (ZB)

CN = 4 (W)

Hybridization energy

Electronegativity difference

Inde

x of

refr

actio

n

Die

lect

ric c

onst

ant

Mel

ting

poin

t

Latti

ce p

aram

eter

Ave

rage

prin

cipa

l qua

ntum

num

ber

Energy gapCarrier mobility

ionicity

metallicity

hardness

Metal

Insulator

Figure by MIT OpenCourseWare.

Lab #1 Appendix 1 Water Vapor and AR Coatings

Optical absorption of water

Courtesy of Martin Chaplin. Used with permission.

Solar spectrum

From Haug, Franz-Josef. "Irradiation Spectrum." Solar Cells: Generating Electricity from Light. Used with permission.

Refractive indices

Material Refractive index Air 1.0

Water 1.33 SiO2 1.5 Si3N4 2.0

Si 3.5

Anti-reflection (AR) coatings

Elimination of reflection on surfaces: � Solar cells � Photodetectors � Photolithography

Quarter wave film

SiO2-on-Si Color Chart

0.05

0.070.10

0.12

0.15

0.17

0.20

0.220.250.27

0.30

0.31

0.320.34

0.35

0.36

0.37

0.390.41

0.42

0.44

0.460.47

0.48

0.49

0.500.52

0.54

0.560.57

0.58

0.60

0.63

0.68

0.720.77

0.80

0.82

0.85

0.86

0.870.890.92

0.95

0.97

0.991.00

1.02

1.05

1.06

1.071.10

1.11

1.12

1.181.19

1.21

1.24

1.251.28

1.32

1.401.45

1.46

1.50

1.54

Dull yellow-green

Yellow to "yellowish"

OrangeCarnation pink

Violet-red

Red-violet

Violet

Blue-violetGreen

Yellow-green

Green

VioletRed-violet

Orange"Yellowish"

Sky blue to green-blue

OrangeViolet

Blue-violet

Blue

Dull yellow-green

Violet-red

Carnation pink to salmon

Tan

BrownDark violet to red-violet

Royal blue

Light blue to metallic blue

Metallic to very light yellow-green

Light gold to yellow - slightly metallic

Gold with slight yellow-orangeOrange to melonRed-violet

Blue to violet-blue

Light green

Green to yellow-green

Yellow-green

Green-yellow

YellowLight orange

Carnation pink

Violet-red

Blue

Blue to blue green

Red-violetViolet

Blue-violet

Blue

Blue-greenGreen (broad)

Yellow-green

Green-yellow

Light-orange or yellow to pink borderline

Carnation pink

Blue-green to green (quite broad)"Yellowish"

Orange (rather broad for orange)

Salmon

Dull, light red-violet

Violet

Blue-violetBlueBlue-green

Violet-red

Yellow to "yellowish"

"Bluish"

Film thickness, microns

Film thickness, microns

Color and comment Color and comment

Figure by MIT OpenCourseWare.

MIT OpenCourseWarehttp://ocw.mit.edu

3.003 Principles of Engineering PracticeSpring 2010

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