Isidoro Iván Cuesta Segura

Inicio de fisuración en probetas miniatura de punzonado

The main objective of the Small Punch Test on pre-cracked specimens is to obtain the fracture properties in those cases where there is not enough material for conducting conventional tests. One of the biggest challenges presented in achieving this goal is the accurate determination of the applied load at the onset of the crack initiation (Papl) during the test, because this point is not clearly reflected in the load-displacement curve obtained. To determine this load, three possible methods have been evaluated: the first one is based on interrupted tests, the second one consists of analyzing the slope of the load-displacement curve and the third one is defined as the compliance method used with compact specimens. The aim of this paper is to present these experimental methods and identify which of them is the most appropriate. As an immediate consequence, the relationship between Papl and the initial crack depth in the pre-cracked SPT specimens has been analyzed.

Effects of Different Types of Rubric-Based Feedback on Learning Outcomes

Nowadays in Higher Education, the teaching procedures that lead to better Learning Outcomes (LO) require continuous analysis. Rubrics such as teaching feedback procedures have demonstrated their effectiveness at heightening the reflection of university students on their own practice. The aims were: 1) to study the effects of different types of rubric-based feedback [from process-oriented feedback to traditional feedback] on LO and on student perceptions of subject matter knowledge (SPKI) in a comparison between students in engineering and students in the social sciences; 2) to analyze the relation between metacognitive skills and motivation with LO and SPKI; 3) to validate the results with structural equation modeling (SEM). The study comprised a total of 171 university students (n = 80 from the mechanical engineering degree and n = 91 from social sciences degree). A quasi-experimental design with a control group was used to test aim 1 and a descriptive correlational design to test aim 2. SEM was applied to validate the results (aim 3). Significant differences were found between both types of rubric-based feedback (process-oriented v. traditional) in relation to LO, though not in relation to SPKI. The effects of the degree type were noted in LO but no in SPKI. Likewise, a relation between SPKI and motivation skills was found in engineering students. Accordingly, the type of degree and the characteristics of the subject modules appear to be determining factors in successful learning, while SPKI is directly linked to motivation skills. The SEM results validated these conclusions.