CHEME 436: Memo Report

Written Report Guidelines

I. STRUCTURE OF THE WRITTEN REPORT

Audience: Plan on writing for a technical manager who already understands the experimental objectives and fundamentals (these should be detailed in the planning report and appended to the memo report). The grading sheet that we will use is provided for your information.

Length: 10 pages of double-spaced text or less not including figures and appendices.

What to omit: do not include a letter of transmittal or a table of contents

What to include: The written report should consist of the following sections (in this order):

A title page: This must be a separate page. Include a descriptive title (limit to 10 words), author, lab section, team members, date, experiment number (1-3). This page must be the only one containing information identifying the author and team. Don't include identifying information in any of the headers or footers.

An "Introduction" section: Describe the project objectives in a few sentences.

A "Materials and Methods" section: Describe the equipment, materials, and procedures you used. Provide one or more schematics (not included in the page limit). The description must be sufficiently detailed to allow a knowledgeable person to reproduce your results.

A "Results" section: Present your major results (in the form of graphs and/or tables), including estimated uncertainties. Do not interpret or analyze in this section. Do not put lengthy data or results tables here, they belong in the appendices. Use the appropriate number of significant figures.

A "Discussion" section: Here you will interpret and analyze your results. This is the most important section! The following example notes trends but lacks sufficient "interpretation":

"The data in Tables 1.1 and 1.2 show that for gases at low density, the viscosity increases with increasing temperature. For liquids, on the other hand, the viscosity usually decreases with increasing temperature. "

Here is an "interpretation" of the above trends:

"This difference in temperature dependence is understandable from a molecular viewpoint. In gases, the molecules are free and travel long distances between collisions to transfer momentum (hence the low viscosity). As temperature increases, the mean molecular speed of the gas increases. This in turn increases the frequency of gas collisions and therefore increases the momentum transfer or viscosity. In liquids, the molecules are not free but closely packed into a 'cage' which prevents them from easy motion. Hence liquids are more viscous than gases. As temperature increases, there is more energy for each molecule to escape this cage and move more freely. Thus, the viscosity of liquids decreases with increasing temperature."

Since the above is well-established, you could also say:

"These trends agree with the standard molecular models of viscosity in gases and liquids [ref.]." and provide an appropriate literature citation.

A "Conclusions" section. Summarize your findings. Relate them to the objectives (as stated in your Introduction). Each conclusion must follow logically from information in the results and discussion sections.

A "Recommendations" section. Recommend further action, experiments or improvements as needed. If desired, you may combine with this section with the "Conclusions" section.

A "Literature cited" section. This section lists all the literature cited in the report (including figures, equations, and theory). For example, the following sentence might appear in the Introduction. "In a tube of circular cross-section, the velocity profile of a Newtonian liquid in fully-developed, laminar flow is parabolic [1]." Number citations (in square brackets) and list them in the order you use them in the text. For each citation, use the following convention, which is standard for the AIChE Journal:

(for books)

1. Bird, R.B., W. E. Stewart, and E. N. Lightfoot, Transport Phenomena, p. 42-47, 126-130, John Wiley and Sons, Inc., New York (1960).

(for journal articles)

2. Grafton, R. W., "Loss of brain mass due to excessive reading of student laboratory reports", Chem. Eng. Edu., 18, 457 (1963).

Always include page number(s) when citing books to point the reader to the appropriate section.

Appendices. These include:

- The Planning Report. Include any corrections resulting from the planning conference. These may be hand-written on a copy of the original report.

- Data and Results. Tabulate all data collected by the team, and all results derived from these. This information is a detailed version of your "Results" section.

- Sample Calculations. Show how you performed each calculation (including error propagation and statistical analysis). Organize in sections by calculation type, with a descriptive title. Work through the calculation step-by-step for a typical case, first symbolically, then with numerical values (making it clear which raw data and/or literature values you are using). Include dimensions of all numerical values and results. We encourage neat, handwritten work (it usually takes much longer to do this using a word processor).

- Signed data sheets. Must contain all the raw data. It must be legible, logically organized, allowing us to trace any result back to the raw data.

- Supplementary Information (optional). Items that support your results but are too detailed or lengthy to include in the main body, such as a computer code. Organize by sections with descriptive titles. Each section must contain enough explanation to stand on its own.

II. HINTS

Sample calculations

We encourage you to use a spreadsheet for repetitive calculations, but you must provide a separate step-by-step procedure in detail for each type of calculation. As a test, ask yourself, "Could someone else easily use my procedures or my data to reproduce my results?" If not, make your sample calculations clearer.

Include units with all values and make sure the unit conversions work out.

Give full source citations for all literature data, including page number and year of publication.

Materials and Methods

Highlight the key aspects of your procedure. What steps are critical in order to get good results? Be specific about quantities used, key dimensions, etc.

Equations and background material

Give a reference unless the equation is common knowledge (such as the Ideal Gas Law) or you derive it. Include only the important equations in the body of your report.

You aren't writing a textbook. Include only the essential background. We don't want a discourse on the subject area. Instead, show us that you understand the subject by doing a good job on the data analysis and interpretation.

Nomenclature

If you include a list of nomenclature, give the units for each symbol. This often helps to clarify your intent. If dimensionless, say so.

Interpretation

Generalize your results and point out important trends.

Do your best to explain anomalies in your results. Do not just speculate: back up your ideas with order-of-magnitude calculations, error propagation analysis, and/or literature values.

Address the assignment you were given. Do notjust state the results. Interpret them and put them in perspective for the intended audience.

III. SPREADSHEETS

Organization

Keep raw data (actual readings you obtained) separate from things you calculated based on them. Include self-explanatory headings with units.

Use worksheets as needed to contain a group of related data and/or calculations. Put the most important worksheets first so they stand out. Use a descriptive label on the worksheet tabs.

It is possible to overdo this. Too many sheets can be confusing.

The basis for all calculations (including error analysis) must be documented in separate sample calculations.

Formatting

Use formatting (shading, borders) to set off raw data from calculated quantities, to distinguish one "run" from another, etc.

Insert comments to provide additional explanation of unusual features.

Insert extra text in cells to help the reader understand what you are doing.

Control the number of significant figures displayed!!! This is especially important for measured values, but also for calculated results.

Be judicious with error bars. They're important, but can be overdone.

III. STYLE AND GRAMMAR

Tense

Use past tense to describe things that you did or that happened. For instance: "The measured pressure drop was 2 kPa. Consequently, we decreased the flow rate." Use present tense to describe things that remain true. For instance: "The viscosity of air decreases with increasing temperature." Avoid changing tense within a paragraph.

Person

Most books on technical writing say that you should avoid use of the first person. If in doubt, that is good advice, but the first person, particularly the use of we, does have a place in technical writing if done in moderation. "We" can make a report seem less stuffy than repeated use of the passive voice. For example, you might say, "We only studied fully turbulent, incompressible flow..." instead of "This work is restricted to consideration of fully turbulent ..."

Equations

Write equations on a line separate from the text. Number them consecutively, with the number in parentheses flush with the right hand margin. Define new symbols immediately following each equation. When referring to a particular equation, abbreviate "equation" as "Eq." "The use of Eq. 5 is ..." Don't abbreviate "Equation" when it is the first word of a sentence, however.

Abbreviations

Avoid abbreviations where possible.

Abbreviate units of measure only when preceeded by a number.

The abbreviations of an SI unit should not be followed by a period unless it is the end of a sentence.

Abbreviations are usually in lower case letters, but there are exceptions. If in doubt, consult a dictionary. Exceptions include Chap., Eq., Fig., Hz, pH, A (ampere), K, J (joule), V (volt).

Do not use contractions in your report.

The "standard" AIChE symbol for a dimensionless group is an upper case N followed by a subscript (NRe, for example). We prefer the practice of most other organizations: an appropriate capital letter and one lower case letter, such as:

Reynolds number

Re

Prandtl number

Pr

Peclet number

Pe

Schmidt number

Sc

Nusselt number

Nu

Tables

Tables should have a title and be numbered in sequence. Place short tables within the text. Long tables should appear on a separate page and should follow the page on which they are mentioned. Give units for all column headings. Footnotes may be included at the bottom of tables.

Figures and Graphs

Figures should be computer-generated. Number graphs serially with all other figures. All figures and graphs should have a title. Titles should be descriptive, not merely a statement of the variables appearing on the ordinate and abscissa. Thus "Friction Factor vs. Reynolds Number" is not a good title. A better one might be "Friction Factor for Turbulent Flow in Smooth Tubes." A figure may be embedded in the text or follow the page on which it is first mentioned.

Center graphs on a page with adequate margins. Label the axes clearly, show the scale and its units and adjust the scale to facilitate the reading of the data. Experimental points may be small circles, triangles, or other shapes. Use horizontal or vertical error bars to indicate the magnitude of the uncertainty in plotted points. You should usually place a smooth, best-fit curve through the points. Show an extrapolation of a curve as a dotted or broken line.

Sometimes smooth curves are illogical. In that case connect points with straight line segments. For example, graphs showing accumulation over intervals of time vs. time, such as yearly production curves, are often plotted this way.

If the objective is to compare sets of data, either superimpose them on a single graph or use multiple graphs with the same scales for the abscissas and ordinates.

Use the same convention for abbreviation (Fig.) as for equations (see above).

Numbers

Write small integers (zero to nine) as words (e.g., "three repetitions," not "3 repetitions"). Write all others as numbers, unless they begin a sentence.

Exception: write the small integers as numbers when they are followed by a unit of measurement, or when many numbers appear in one paragraph .

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CHEME 436