Acceptance of claims made in scientific research articles depends on the "stance" authors take and their resources for "appraisal" (Martin and White, http://www.grammatics.com/appraisal). "Stance" has been defined as "the ways authors project themselves into their texts to communicate their relationship to subject matter and the readers", ["Writing Texts, Processes and Practices" (1999)], while "appraisal" represents the ways authors' evaluations, attitude and emotions are expressed and managed interpersonally (http://www.grammatics.com/appraisal/AppraisalGuide/Unframed/Appraisal-Overview.htm). This paper explores some appraisal resources employed by authors of research articles, and the means by which scientific authors are positioned interpersonally and intertextually. It looks at resources by which authors express their attitude and certainty to claims, and create solidarity between themselves and their readers. The paper explores three categories of markers: "attitude", "certainty", and "common knowledge markers", and its main aim is to compile a taxonomy of the lexical and discourse-based realisations of these markers and their pragmatic functions, as they are manifested in RAs from the field of electronic and electrical engineering. The analysis indicates that employment of these markers by authors assists them in asserting their authority and expertise by presenting claims as given based on shared knowledge and consensual understandings, exploiting the complex dynamics of power and solidarity in order to gain readers' agreement and community consensus.