Common Errors II. MSE 3333 TA Will Kurlinkus

Transcription

1 Common Errors II MSE 3333 TA Will Kurlinkus I. Higher Order Concerns Start Specific and Stay Specific Remember the Goals of the Experiment Avoid broad opening and closing statements in your abstracts, intros, and conclusions. Some of you start with proclamations like, In today s modern world, steel is the most important metal to the field of engineering. I would recommend cutting this line entirely and starting with something like, This experiment studies the effects of air cooling, water quenching, and water quenching and tempering on 1018, 1045, and 4340 steels. This new opening line immediately informs your reader what the experiment is about and what steels are going to be studied. But, if you wanted to keep the line about steel being important to the field of engineering, you must tell your reader, first, why it is important and, second, how that importance relates to the objectives of the experiment: o The microstructures of steel can be manipulated through heat treatments and alloying content to create numerous mechanical properties (hardness, hardenability, malleability, etc.); because of this transformability, steel has become one of the most important metals to material engineering. o This new sentence does a couple of things. First, it relates directly to the objectives of the experiment uncovering the relationship between microstructure, steel type, cooling type, and mechanical properties. Rather than simply saying steel is important, I relate that importance to steels transformability. Second, this new sentence actually lists the types of mechanical properties that are being looked at in this experiment (hardness, hardenability, malleability), rather than simple saying numerous mechanical properties and leaving it at that. Make every sentence work for you in getting across the goals and results of the experiment. No sentence should speak in generalities about the benefits of steel, the importance of engineering. o Bad: The results of this experiment can be used in a practical manner. o Better: The results of this experiment can help welding engineers determine which types of steels and heat treatments will create the best steel microstructure for their application. For instance, welds might be viewed as a variety of heat treatment, thus, this report aids in forming conclusions on which steels and heat treatments will create desirable properties (strength, malleability, etc.) when welded.

2 page 2 Need More Interpretation in the Discussion Section Some of you have been using the analysis section as a place to just repeat your results section in sentence form. The point of the discussion section is to explain WHY your results look like they did in terms of the theory of your introduction and the overall objectives of the experiment. I need more analysis of what this information means. Give me a sentence or two that directly relates cooling rates, microstructures, and steel properties. Compare the three treatments of each steel. And then compare the three types of steels with one another. Don t just describe what happened but rather describe Why what happened, happened. Your Discussion Section Needs Direct References to Your Results Section This is the opposite problem of the last common error. Some of you have been giving nice descriptions of why things happened, but you haven t been referring directly to YOUR DATA. The discussion section needs to refer to the tables and figures in your results section. Every time you make a claim like, When tempering, a steel that is rapidly cooled to form martensite is brought back up to an elevated temperature, though not above the eutectoid temperature. This re-heating allows carbon that is saturated in the martensite to precipitate out and form other carbides. You need to give specific figure and table numbers from your results section that supports those claims. o When tempering, a steel that is rapidly cooled to form martensite is brought back up to an elevated temperature, though not above the eutectoid temperature. This reheating allows carbon that is saturated in the martensite to precipitate out and form other carbides. Figures (water-cooled 1045) demonstrate this result when compared to Figures (tempered 1045). The tempered samples lack the. Introductory Sentences Before Groups of Figures in Your Results Section Don t just start your results section with images and tables. Your figures should be grouped logically (either by steel type or cooling type) and have a sentence or two before each grouping describing the important and common features of each. You don t want to get into What specifically should the reader pay attention to when looking at the figures? o Figures 9-12 show the effects of water quenching and tempering on 1018 at magnifications of 200X and 1000X. Martensite appears as the darker areas that are needle-like. The white areas surrounding the martensite indicate ferrite along grain boundaries. The estimated phase

3 page 3 fractions of this sample were chiefly martensite with less significant amounts of ferrite. II. Readability Concerns Too many Subordinate Clauses Some of you get into extra-long sentences with numerous subordinate clauses, which end up being hard to read. You should normally have one and at the most two subordinate clauses. Subordinate clauses are clauses that can't stand on their own and, generally, begin with something like "after, although, as, because, before, though, since, whereas, where, that, which, while, than, since, once, after, until, once" If you have more than two of these words in a single sentence, you probably need to split up the sentence. o However, when both steels are water quenched, more martensite is formed because 1045 has.05% more carbon than 4340, which causes 1045 to be harder since it has more carbon in the interstitial sites which prevent dislocation motion. o Better: However, when both steels are water quenched, more martensite is formed because 1045 has.05% more carbon than This extra martensite causes 1045 to be harder than 4340 since 1045 has more carbon in its interstitial sites. Such carbon prevents dislocation motion. Alternate Between Short and Long Sentences Related to overly-long sentences, it s good practice to alternate between short and long sentences. Don t have 7 short or long sentence in a row. It s also typically a good idea to put your most important concepts in short sentences because short sentences are usually easier to comprehend and remember than long sentences they pack more punch. Unclear Pronoun Usage When you use pronouns like it you need to make sure you are clear about what it is. If you have numerous nouns in the preceding sentence. You probably can t use it. o For instance, Hardenability is defined by the ease with which the martensitic transformation is effected, and is measured by depth on a jominy test, after putting it through a heat treatment process.

4 page 4 o Here, it could refer back to hardenability, martensitic transformation, or the jominy test or something from a preceding sentence. o See: ub_category_id=6&article_id=91 Need More Connective Words In your introductions and discussion sections, many of your sentences seem a little disjointed. I don t know how your paragraph is progressing or how each sentence is related to one another. Therefore, you need some more connective and transition words like: however, therefore, whereas, but, also, too, thus, in addition. o See: and Need more Process Connective Words In your procedure section, many of you need to have some more connective words, indicating time, in order to make your paragraphs less choppy. Add some words like next, then, after, etc. o See: and Adding This and That (But not free-floating This) Throughout your reports look for places where you can add referential terms like this and that that refer back to the previous sentence. It ups the coherence and readability of reports by about 20%. o The pearlite and ferrite should lower the hardness of the 1045 steel below 4340 s hardness. The higher amount of ferrite in the 4340 steel could be the cause of that lower hardness. III. Word Use Concerns While vs. Whereas vs. Although Use while to talk about simultaneous occurrences in time and whereas to talk about comparison. o Time measurements were taken while the 1018 samples air cooled.

5 page 5 o The 1018 air-cooled samples were relatively soft whereas the 1018 water-cooled samples were hard and brittle. Similarly, while should be used to indicate time; use although to mean in spite of the fact. o Although the 1018 should have been the softest because of phase transformation, it was actually the hardest. Important Don t use the word important unless you tell your reader specifically why something is important in relation to the specifics of the experiment: o Hardness and hardenability are important when discussing heat treating and welding of steels. o Add to this sentence why these two measurements are important to the goal of this experiment--understanding the relationship between microstructures and heat treatments. Experiment vs. Lab vs. Report Refer to the process you went through as an experiment instead of a lab. Experiment both sounds more "professional" and refers to the process of both doing lab work and analyzing results rather than only performing the work under your procedures. In addition, use report to refer to the document itself. o Experiment: The overall process (both the lab work and your analysis and results) the most inclusive term. The term you generally want to be using. o Lab: Refers to the specific work that you did in the lab the polishing, preparation, and metallography. Generally, avoid this term. o Report: refers to the document itself. Follow, Consistent with, corroborate vs. Agree with When talking about how your results match up or disagree with the theoretical predictions of diagrams use follow, are consistent with, corroborate, correlate to, but I would avoid agree with. Agree with is slightly more informal and gives a little too much agency to the figures and charts, as if they had power to change the results.

6 page 6 IV. Punctuation and Grammar Concerns Commas and Independent Clauses Use a comma+but/and if both sides of the sentence are complete (independent clauses) and could stand on their own. o No Comma: Martensite is formed when a steel is heated to a high temperature (950o C for this experiment) and then cooled rapidly. o Needs a Comma: Martensite is formed when a steel is heated to a high temperature (950o C for this experiment), and then it cooled rapidly. o Then cooled rapidly is not a complete sentence because it doesn t have both a subject and a verb. Then, it cooled rapidly. Is a complete sentence because it has both a subject it and a verb cooled. o See Rule 1, at: Dependent Clauses and Commas: You almost always want to place a comma before the words which, where, when while, until as, after, because, in general, they mark dependent clauses. See my explanation on the first common errors sheet or See: Introductory Words Phrases and Clauses Use a comma to set off introductory words, phrases, and clauses. See: Hyphen vs. Dash There are three types of dashes; none of them should have spaces before or after. o A hyphen - is used to form compound adjectives: air-cooled martensite. o An en dash (called that because it takes up the same amount of space as the letter n) is used between numbers: The years o An em dash (two hyphens put together--) is used to split up sentences, introduce lists, or for asides: Three steels 1018, 1045, and 4340 were used in this experiment. Color and Tables

7 page 7 A note on using color in your tables and, really, throughout your document: In professional life when you re writing up a report, you ll want to make sure that the contrast between things and the colors you re using show up well in a black and white print out because reports are often printed and photocopied (and, many times, color printing isn t used).