# Scientific Writing (Illustration)

```Illustration:
The Meshing of Words
With Images
Keep it as simple as possible, yet
no simpler.
Albert Einstein
X-ray photograph of DNA
[Rosalind Franklin, 1952]
Two types of illustrations exist: tables and figures
Table 1. Reactor power levels in
Chernobyl accident [Wolfson, 1991].
Pressurizer
Date
Time
Power Level
4/25
1:00 am
3200 MW
4/25
2:00 pm
1600 MW
4/25
11:10 pm
1600 MW
4/26
1:00 am
30 MW
4/26
1:19 am
200 MW
4/26
1:23 am
2,000,000 MW
Coolant
Loss
Reactor
Vessel
Steam
Generator
Core
Figure 1. Simplified diagram of
nuclear reactor [Wolfson, 1991].
Tables can present words as well as numbers
Table 2. Sequence of events in the Chernobyl accident [Wolfson, 1991].
Date
Time
Power Level
Event
April 25
1:00 a.m.
3200 MW
Operators begin power descent
April 25
2:00 p.m.
1600 MW
Power descent delayed for 9 hours
Emergency core-cooling system disconnected
April 25
11:10 p.m.
1600 MW
Operators switch off automatic control
Power descent resumed
April 26
1:00 a.m.
30 MW
April 26
1:19 a.m.
200 MW
April 26
1:23 a.m.
2,000,000 MW
Power minimum reached
Operators pull rods beyond allowable limits
Operators start two additional coolant pumps
Operators violate coolant flow limits
Power surges by factor of 10,000 in 5 seconds
When presenting numerical data, you
choose between tables and graphs
Table 2. Blood glucose
levels [Carlson, 1982].
Time
(hour)
Normal
(mg/dl*)
Diabetic
(mg/dl)
midnight
2:00
4:00
6:00
8:00
10:00
noon
2:00
4:00
6:00
8:00
10:00
100.3
93.6
88.2
100.5
138.6
102.4
93.8
132.3
103.8
93.6
127.8
109.2
175.8
165.7
159.4
72.1
271.0
224.6
161.8
242.7
219.4
152.6
227.1
221.3
* decaliters/milligram
300
Breakfast
Lunch
Dinner
250
Diabetic
Blood
200
Glucose
Level
150
(mg/dl)
100
Normal
50
0
12:00
6:00 am
12:00
6:00 pm
Hour
Figure 11. Blood glucose levels for
normal individual and diabetic
[Carlson, 1982].
12:00
Line graphs are common
in engineering and science
2000
1500
Temperature
(K)
1000
Experiment
Simulation
500
0
0
2
4
6
8
10
Distance From Burner (mm)
Figure 3. Computational and experimental temperatures for
laminar diffusion flames [Sandia, 1987].
Bar graphs compare wholes
30
Normal range
20
7-10
Cells%
10
112–175
211–366
Flight Duration (Days)
Figure 4. Response of T-cells in cosmonauts after short-term
and long-term flights [Konstantinova, 1991].
Gantt charts are a type of bar charts
1979
1981
1983
1985
1987
Construction
Test and Evaluation
Power Production
Figure 5. Schedule for the construction, evaluation, and production
phases of the Solar One Power Plant.
1989
Pie graphs compare parts of a whole
Medical and research wastes
(16%)
Industrial wastes
(28%)
Power Reactor
Industrial
Medical
Government
Government wastes
(2%)
Power reactor wastes
(64%)
Figure 5. Volume of low-level nuclear wastes from various
sources [League, 1985].
Graphs come in many forms
Average dose: 160 mrem
85 mrem
Natural
Sources
70 mrem
Medical
Sources
{
Fallout: &lt; 3mrem
Occupational: &lt; 1mrem
Nuclear power: &lt; 1mrem
Figure 6. Estimated annual dose of radiation in the United
States [GPU Nuclear, 1985].
When presenting images, you choose between
photographs, drawings, and diagrams
4
1
Combustor
2
Compressor
3
Turbine
The main advantage of photographs is realism
60 seconds
59.5 seconds
59 seconds
Figure 2. Space Shuttle Challenger, from about 59 seconds to 60
seconds into launch (January 28, 1986). On the right rocket, flame
first becomes visible and then impinges on tank.
One advantage of drawings is control of detail
Combustor Simulator
Turbine Vanes
Secondary
Flow
Dilution Jet
Primary
Flow
Secondary
Flow
Film-Cooling
Holes
Figure 5. Wind tunnel experiment at Virginia Tech for evaluating
film-cooling designs for the blades of gas turbine engines [Thole
and others, 2000].
The main advantage of a diagram is the ability to
show flow of a variable through a system
Figure 8. Schematic of test stand for evaluating
components of an air conditioner design.
Scientists and engineers often use illustrations
that are too complex for the text
The thermal storage system
stores heat in a huge, steelwalled tank. Steam from
through heat exchangers
to heat the thermal oil,
which is pumped into the
tank. The tank then
provides energy to run a
steam generator to
produce electricity. A
schematic of this system
is shown in Figure 5.
DSPH
TSU
TSH
FLASH
TANK
FT
DEARATOR
TURBINE
HP
HTR
Figure 5. Schematic of thermal
storage system.
HOT
WELL
T
S
S
G
The precision of the illustrations
should reflect the precision of the text
The thermal storage system, shown in Figure 6, stores
heat in a huge, steel-walled tank. Steam from the solar
receiver heats a thermal oil, which is pumped into the tank.
The tank then provides energy to run a steam generator to
produce electricity.
650&deg;F
580&deg;F
Heat
Exchanger
solar
435&deg;F
575&deg;F
Thermal
Tank
425&deg;F
530&deg;F
Heat
Exchanger
425&deg;F
Figure 6. Schematic of thermal storage system for the solar
power plant.
steam
generator
250&deg;F
For clarity, you should introduce and
explain illustrations in the text
..., as shown in Figure 7.
Figure 7. Title of figure. Some formats allow you extra
sentences to explain unusual details.
Inconsistencies between text and
images disrupt fluidity
The testing hardware of the
rocket shown in Figure 8 has
five main components: camera,
digitizer, computer, I/O interface,
and mechanical interface.
Commands are generated by the
computer, then passed through
the I/O interface to the
mechanized interface where the
keyboard of the ICU is operated.
The display of the ICU is read
with a television camera and
then digitized. This information
is then manipulated by the
computer to direct the next
command.
CONTROL
TERMINAL
PRINTER
CAMERA
DIGITIZER
ROCKET
COMPUTER
ELECTROMECHANICAL
INTERFACE
Figure 8. Testing hardware.
Illustration is the meshing of words with images
Our system for testing the launch controls of the rocket consists
of four main parts: computer, electro-mechanical interface, camera,
and digitizer. In this system (shown in Figure 9), the computer
generates test commands to the rocket through the electromechanical interface. The test results are read with a television
camera, and then digitized. The computer receives the information
from the digitizer, and then directs the next test command.
1
Computer
4
Digitizer
2
ElectroMechanical
Interface
3
Camera
Figure 9. System to test launch
controls for rocket.
Rocket
```