<bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Background:</b> This study investigates linguistic characterizations in the form of linguistic co-occurrence patterns in discussion sections of English research articles (RAs) in an engineering discipline (i.e., chemical engineering) and linguistic variations that distinguish discussion sections of high-impact articles from those in low-impact articles. <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Research questions:</b> 1. What underlying linguistic characterizations are salient in RA discussions in chemical engineering? 2. Are there any differences in the identified linguistic characterizations of discussion sections between high- and low-impact RAs? <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Literature review:</b> In the process of composing RAs, the discussion section is a difficult and challenging part-genre to write. The rhetorical organization of RA discussions has been examined extensively through Swales's English for Specific Purposes genre analysis. However, the linguistic characterizations of RA discussion sections remain unclear and the question of whether discernible differences exist between discussions of high- and low-impact RAs in a specialized engineering discipline remains unanswered. <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Methodology:</b> This study used Biber's multidimensional (MD) analysis method. In response to the first research question, factor analysis (in this study, principal component analysis) was adopted to identify the linguistic characterizations in the form of linguistic co-occurrence patterns (“dimensions”) in 213 RA discussion sections extracted from chemical engineering RAs. To answer the second question, the independent t-test was implemented to compare the high- and low-impact RA discussion sections in the identified dimensions. <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Results and conclusions:</b> Six linguistic characterizations in the form of linguistic co-occurrence patterns were identified in RA discussion sections: 1. involvement and interactivity, 2. non-narration versus narration, 3. evaluative statements with further explanations and elaborations, 4. informational density, 5. stating results/claims, and 6. expression of denial relationships toward statement or experimental findings. The results suggest the linguistic characterizations in RA discussion sections and interesting differences in the high- and low-impact RA discussion sections, especially in Dimensions 1, 3, and 5. Reasons for the linguistic variations in the identified dimensions are discussed, followed by the pedagogical implications for reading or writing RAs for international scientific communication.

This study aims to delineate the rhetorical organization of research article (RA) discussion sections in an engineering discipline and explore the variations that distinguish discussion sections of high-impact and low-impact RAs. Research questions: What is the rhetorical organization of RA discussions in chemical engineering? What are the similarities and differences in the use of rhetorical moves and steps in RA discussions of high-impact and low-impact articles? Literature review: Some studies have been conducted using Swales' move analysis with regard to the identification and textual comparisons of RA discussion sections. However, it remains to be determined whether RA discussions of the high- and low-impact articles within a single discipline display the variation in rhetorical patterns. Research methodology: A total of 40 RA discussions published between 2005 and 2015 were chosen based on five-year journal impact factor and citations of the articles in which they were published. Swales' move analysis was used to compare rhetorical moves and steps in both sets of RA discussions. Results and discussion: The study identified the rhetorical organization of RA discussions in the field of chemical engineering. The findings indicate that discussion sections of high-impact articles tend to make use of the “comment on results” move. Explanations of the similarities and differences in the employment of moves and steps are provided. Implications of the findings are discussed.