Although there is consensus in the literature that writing skills are important in STEM (Science, Technology, Engineering, and Mathematics) studies, they are often neglected. However, some efforts have been made to correct this deficiency, one of them being the development of assessment rubrics. This study seeks to contribute to the discussion by presenting the results of the application of a rubric designed to assess the writing skills of a group of 3rd year engineering students. This rubric, which includes linguistic and rhetorical-organizational criteria alongside the mathematical and technical, was used to assess a number of written exercises and essays submitted by students in a 15-week course. The main interest of this study was to test the efficacy of the rubric as a diagnostic tool, conceived to detect the areas of improvement in the students’ written performance and, ultimately, to also help them to achieve higher levels of competence. This goal was achieved, as one of the main conclusions of the study is that, although students usually master the technical aspects of the course, they must improve the linguistic and rhetorical aspects of their written communication. It can likewise be said that all the participants involved in the study profited in one way or another from the application of the rubric and contributed to identifying the ways in which the rubric itself can be improved for future application.

Although Error Analysis (EA) has been broadly used in Foreign Language and Mother Tongue learning contexts, it has not been applied in the field of engineering and by STEM (Science, Technology, Engineering, and Mathematics) students in a systematic way. In this interdisciplinary pilot study, we applied the EA methodology to a wide corpus of exercises and essays written by third-year students of mechanical engineering, with the main purpose of achieving a precise diagnosis of the students’ strengths and weaknesses in writing skills. For the analysis to be as exhaustive as possible, the errors were typologized into three main categories (linguistic, mathematical, and rhetorical–organizational), each of which is, in turn, subdivided into 15 items. The results show that the predominant errors are rhetorical–organizational (39%) and linguistic (38%). The application of EA permits the precise identification of the areas of improvement and the subsequent implementation of an educational design that allows STEM students to improve their communicative strategies, especially those related to the writing skills and, more precisely, those having to do with the optimal use of syntax, punctuation, rhetorical structure of the text, and mathematical coherence.

The stability of integrators dealing with high order Differential Algebraic Equations (DAEs) is a major issue. The usual procedures give rise to instabilities that are not predicted by the usual linear analysis, rendering the common checks (developed for ODEs) unusable. The appearance of these difficult-to-explain and unexpected problems leads to methods that arise heavy numerical damping for avoiding them. This has the undesired consequences of lack of convergence of the methods, along with a need of smaller stepsizes. In this paper a new approach is presented. The algorithm presented here allows us to avoid the interference of the constraints in the integration, thus allowing the linear criteria to be applied. In order to do so, the integrator is applied to a set of instantaneous minimal coordinates that are obtained through the application of the null space. The new approach can be utilized along with any integration method. Some experiments using the Newmark method have been carried out, which validate the methodology and also show that the method behaves in a predictable way if one considers linear stability criteria.