Being Precise How upset [Max Planck] was whenever he inadvertently gave out the wrong information, whether in Engineering publication or casual conversation, since despite all efforts at retraction, he knew that at least some untruth would always persist. Lise Meitner Concise Familiar Clear Fluid Precise Forthright

Precision means choosing the right words and appropriate level of detail detail choosing the right word choosing appropriate level of detail word right word word

Choose words carefully because many engineering terms have specific meanings The last decade has seen a rapid development of new techniques for studying the enormously complex phenomena associated with the develop- ment of sparks and other gas discharges. The last decade has seen a rapid development of new techniques for studying the enormously complex phenomena associated with the develop- ment of sparks and other gas discharges. spark: the transient irreversible event from one steady state of the electrical breakdown process to another. gas discharge: any of the three steady states of the electrical breakdown process. Voltage Current spark discharge

Another consideration in choosing the correct word is the connotation Denotation dictionary meaning adequate: sufficient; enough for what is required Connotation suggested meaning adequate: sufficient adequate: insufficient

In choosing the right word, you first have to consider the denotation Denotation dictionary meaning concrete agglomerate of aggregate and hydraulic cement cement a material, usually ceramic, for bonding solids aggregate coarse particles such as sand or gravel hydraulic cement cement that bonds by a reaction with water agglomerate small particles bonded into an integrated mass

Words have both denotations and connotations inexpensive unusual simple clear cost-effective novel streamlined cheap strange simplistic Negative NeutralPositive obvious

Precision means choosing the right words and appropriate level of detail detail choosing the right word choosing appropriate level of detail word right word word

Generalities that are not anchored with specifics are soon forgotten After recognizing some problems with the solar mirrors, we took subsequent corrective measures. Trash After finding that high winds (and not hail) had cracked the ten solar mirrors, we began stowing all mirrors in a horizontal position during thunderstorms.

For precise language, you should avoid over-specifying details The number of particular hydrocarbon combinations in our study is enormous. For example, the number of possible C 20 H 42 is 366,319 and the number for C 40 H 82 is 62,491,178,805,831. The number of hydrocarbon combinations in our study is enormous. For example, the number of possible C 40 H 82 is more than 62 trillion.

For precision, you must choose the appropriate level of detail Operations at the plant stopped momentarily because the thermal storage charging system desuperheater attemperator valve was replaced. Operations at the plant stopped for 1.5 hours so that a valve in the thermal storage system could be replaced.

Being Clear When you are out to describe the truth, leave elegance to the tailor. Albert Einstein Concise Familiar Clear Fluid Precise Forthright

Clarity means making sure that no one misreads you Avoiding ambiguities languagelanguagelanguagelangu?? Streamlining language language

R.I.P. Complex wording also buries ideas This study will consider why current solar energy systems, such as Solar One, have not reached the commercial stage and will find out what steps we can take to make these systems commercial. The goal of this study is to develop a commerciali- zation strategy for solar energy systems by analyzing factors impeding early commercial projects (i.e., SOLAR ONE) and by identifying the potential actions that can facilitate the viability of the projects.

Stacking adjectives before nouns swallows the ideas Solar One is a solar-powered pilot plant located near Barstow, California. Solar One produces 10 megawatts of electricity by capturing solar energy in a central receiver design. Solar One is a 10 megawatt solar thermal electric central receiver Barstow power pilot plant.

Complex sentences misdirect readers The goal of the work was to confirm the nature of electrical breakdown of nitrogen in uniform fields at high pressures and electrode gaps which approach those obtained in engineering practice, prior to the deter- mination of the processes which set the criterion for breakdown in the above-mentioned gas in uniform and non-uniform fields of engineering significance. At high pressures (760 torr) and typical electrode gap distances (1 mm), the electrical breakdown of nitrogen was studied in uniform fields.

The more muddled the original, the more revisions are needed to streamline it At high pressures (760 torr) and typical electrode gap distances (1 mm), the electrical breakdown of nitrogen was studied in uniform fields. In our study, we examined the electrical breakdown of nitrogen in uniform fields. For these experiments, the electrode gap distances were typical (1 mm), while the pressures were relatively high (760 torr).

The "Big Bang" is the most credible theory for the creation of the universe. Nevertheless, it explains the creation of only helium and hydrogen. What about the other elements? Many scientists believe that those elements came from nuclear reactions in the life and death cycles of stars. Archaic structures sound unnatural In that the "Big Bang," currently the most credible theory for how the universe was created, explains only hydrogen and helium, we are left to theorize as to how all the other elements came into being. Having studied the nuclear reactions that constitute the life and death cycles of stars, many scientists believe that there lies the key.

One measure for the complexity of the writing is the Gunning Fog Index In the index, the complexity of the writing depends on (1) the lengths of sentences (2) the lengths of words Desired index values for scientific writing are 10-12: New York Times (11) Scientific American (12) F i = 0.4 ( (N w / N s )+ P lw ) N w = number of words in a typical paragraph N s = number of sentences in the paragraph P lw = percentage of long words in the paragraph

Exercise Calculate the fog indices of the Bohr paragraph (top of page 89) and the Einstein paragraph (bottom of page 116). F i = 0.4 ( (N w / N s )+ P lw ) N w = number of words in random paragraph N s = number of sentences in the paragraph P lw = percentage of long words in the paragraph (> 3 syllables) not first word in sentence; no proper nouns; no verbs that acquire third syllable on ending

Clarity means making sure that no one misreads you Avoiding ambiguities languagelanguagelanguagelangu?? Streamlining language language

An ambiguity is a group of words that can have more than one meaning On the second day the knee was better and on the third day it had completely disappeared. On the second day the knee was better and on the third day the pain in the knee had completely disappeared. Dr. Richard Lederer Journal of Court Reporting

Word choice often causes ambiguities We wanted to reduce the vibration of the fan at the exhaust as the exhaust ducting was cracking. We wanted to reduce the vibration of the fan at the exhaust because the exhaust ducting was cracking.

Syntax often causes ambiguities, especially with adverbs Only I tested the Labrador for rabies yesterday. I only tested the Labrador for rabies yesterday. I tested the only Labrador for rabies yesterday. I tested the Labrador only for rabies yesterday. I tested the Labrador for rabies only yesterday.

Also causing ambiguities are pronouns, particularly the pronouns it and this Although engineers realized the design flaws in the Titanic soon after its sinking in 1912, the reasons for the severe damage inflicted by the iceberg remained a mystery until its discovery in Although engineers realized the design flaws in the Titanic soon after its sinking in 1912, the reasons for the severe damage inflicted by the iceberg remained a mystery until the Titanic’s discovery in 1985.

Also causing ambiguities are pronouns, particularly the pronouns it and this Because the receiver presented the radiometer with a high flux environment, it was mounted in a silver-plated stainless steel container. Because the receiver presented the radiometer with a high flux environment, the radiometer was mounted in a silver-plated stainless steel container.

Not having commas after introductory phrases or clauses often causes ambiguities As light hydrocarbons evaporate the oil vapor pressure falls. As light hydrocarbons evaporate, the oil vapor pressure falls.

When commas are missing within lists, ambiguities often occur We examined neat methanol and ethanol and methanol and ethanol with 10% water. We examined four fuels: neat methanol, neat ethanol, methanol with 10% water, and ethanol with 10% water.

Being Clear When you are out to describe the truth, leave elegance to the tailor. Albert Einstein Concise Familiar Clear Fluid Precise Forthright

Formatting Scientific Documents

In scientific writing, formats vary considerably to serve different situations Formal Reports Presentation Slides Journal Articles

Not all rules of format are constant Reports Sandia Laboratories Figure 1 Table 1 equation 1 Textbooks Prentice-Hall Fig. 1 Table 1 equation (1) Journals ASME fig. 1 table 1 Eq. 1

Format is the arrangement of type on the page typography layout

Arial abcdefghijklmnopqr stuwxyz Arial Narrow abcdefghijklmnopqr stuwxyz Comic Sans abcdefghijklmnopqr stuwxyz Times New Roman abcdefghijklmnopqr stuvwxyz Garamond abcdefghijklmnopqr stuvwxyz Courier abcdefghijklmnopqr stuvwxyz Each typestyle has its own personality and power Serif Sans Serif

Avoid large blocks of capital letters WORDS SET IN ALL CAPS USE MORE SPACE THAN TEXT SET IN LOWERCASE. Words set in all caps use more space than words set in lowercase. TYPE IS TO READ Type is to read

Morton-Thiokol’s presentation to NASA suffered because of all capital letters on the slides Morton-Thiokol Presentation to NASA January 27, 1986 PRIMARY CONCERNS - FIELD JOINT - HIGHEST CONCERN EROSION PENETRATION OF PRIMARY SEAL REQUIRES RELIABLE SECONDARY SEAL FOR PRESSURE INTEGRITY IGNITION TRANSIENT - (0-600 MS) (0-170 MS) HIGH PROBABILITY OF RELIABLE SECONDARY SEAL ( MS) REDUCED PROBABILITY OF RELIABLE SECONDARY SEAL ( MS) HIGH PROBABILITY OF NO SECONDARY SEAL CAPABILITY STEADY STATE - (600 MS - 2 MINUTES) IF EROSION PENETRATES PRIMARY O-RING SEAL - HIGH PROBABILITY OF NO SECONDARY SEAL CAPABILITY BENCH TESTING SHOWED O-RING NOT CAPABLE OF MAINTAINING CONTACT WITH METAL PARTS GAP OPERATING TO MEOP BENCH TESTING SHOWED CAPABILITY TO MAINTAIN O-RING CONTACT DURING INITIAL PHASE ( MS) OF TRANSIENT

Choose a type size that is easy to read 48 point 36 point 24 point 18 point 14 point 12 point 10 point 8 point posters presentation slides titles text footnotes

In your layouts, use white space for association, emphasis, and hierarchy space for margins space for illustrations space for headings

Follow the format that is expected or required for the situation

Keep it as simple as possible, yet no simpler. Albert Einstein Illustration: The Meshing of Words With Images X-ray photograph of DNA [Rosalind Franklin, 1952]

Table 1. Reactor power levels in Chernobyl accident [Wolfson, 1991]. DateTimePower Level 4/251:00 am3200 MW 4/252:00 pm1600 MW 4/2511:10 pm1600 MW 4/261:00 am30 MW 4/261:19 am200 MW 4/261:23 am2,000,000 MW Figure 1. Simplified diagram of nuclear reactor [Wolfson, 1991]. Coolant Loss Reactor Vessel Core Pressurizer Steam Generator Two types of illustrations exist: tables and figures

Table 2. Sequence of events in the Chernobyl accident [Wolfson, 1991]. April 25 April 26 DateTimePower LevelEvent 1:00 a.m. 2:00 p.m. 11:10 p.m. 1:00 a.m. 1:19 a.m. 1:23 a.m MW 1600 MW 30 MW 200 MW 2,000,000 MW Operators begin power descent Power descent delayed for 9 hours Emergency core-cooling system disconnected Operators switch off automatic control Power descent resumed 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 Tables can present words as well as numbers

When presenting numerical data, you choose between tables and graphs Time (hour) midnight 2:00 4:00 6:00 8:00 10:00 noon 2:00 4:00 6:00 8:00 10:00 Normal (mg/dl*) Diabetic (mg/dl) Table 2. Blood glucose levels [Carlson, 1982]. * decaliters/milligram

Temperature (K) Distance From Burner (mm) Figure 3. Computational and experimental temperatures for laminar diffusion flames [Sandia, 1987]. Experiment Simulation Line graphs are common in engineering and science

Figure 4. Response of T-cells in cosmonauts after short-term and long-term flights [Konstantinova, 1991]. Cells% Flight Duration (Days) – –366 Normal range Bar graphs compare wholes

Figure 5. Schedule for the construction, evaluation, and production phases of the Solar One Power Plant. Task Construction Test and Evaluation Power Production Gantt charts are a type of bar charts

Industrial wastes (28%) Medical and research wastes (16%) Power reactor wastes (64%) Power Reactor Industrial Medical Government Government wastes (2%) Figure 5. Volume of low-level nuclear wastes from various sources [League, 1985]. Pie graphs compare parts of a whole

Figure 6. Estimated annual dose of radiation in the United States [GPU Nuclear, 1985]. Average dose: 160 mrem Natural Sources Medical Sources 85 mrem 70 mrem { Fallout: < 3mrem Occupational: < 1mrem Nuclear power: < 1mrem Graphs come in many forms

When presenting images, you choose between photographs, drawings, and diagrams Compressor Combustor Turbine

The main advantage of photographs is realism 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. 59 seconds 59.5 seconds 60 seconds

One advantage of drawings is control of detail Figure 5. Wind tunnel experiment at Virginia Tech for evaluating film-cooling designs for the blades of gas turbine engines [Thole and others, 2000]. Secondary Flow Primary Flow Secondary Flow Turbine Vanes Combustor Simulator Dilution Jet Film-Cooling Holes

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.

Figure 5. Schematic of thermal storage system. RECEIVER FLASH TANK HP HTR DEAR- ATOR HOT WELL TSSGTSSG TURBINE TSU DSPH TSH FT The thermal storage system stores heat in a huge, steel- walled tank. Steam from the solar receiver passes 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. Scientists and engineers often use illustrations that are too complex for 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. Figure 6. Schematic of thermal storage system for the solar power plant. steam generator 650°F 580°F 425°F 435°F solar receiver 575°F 425°F 530°F 250°F Thermal Tank Heat Exchanger Heat Exchanger The precision of the illustrations should reflect the precision of the text

Figure 7. Title of figure. Some formats allow you extra sentences to explain unusual details...., as shown in Figure 7. For clarity, you should introduce and explain illustrations in the text

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. PRINTER CONTROL TERMINAL COMPUTER DIGITIZER CAMERA ELECTRO- MECHANICAL INTERFACE ROCKET Figure 8. Testing hardware. Inconsistencies between text and images disrupt fluidity

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 electro- mechanical 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. Figure 9. System to test launch controls for rocket. Camera Digitizer Computer Electro- Mechanical Interface Rocket Illustration is the meshing of words with images