Studies of the effect of tracer activity on time-averaged positron emission particle tracking measurements on tumbling mills at PEPT Cape Town

The statistical uncertainties associated with time-averaged positron emission particle tracking (PEPT) measurements of the position, velocity and acceleration of a small tracer particle have been investigated. Experiments were undertaken using the ECAT 'EXACT3D' PET scanner recently installed at the facilities of PEPT Cape Town at iThemba LABS, South Africa. Small "button" sources of Ga-68 were attached to the outer shell of a small mill and PEPT data were recorded over several half-lives, for the cases of the mill being empty and entirely filled with steel balls. The effect of tracer activity on the statistical uncertainties in the positions, velocities and accelerations derived from the measurements was investigated, as a first step towards fully quantifying the uncertainties associated with tracking particles via PEPT in laboratory-scale tumbling mills

Embodiment in physics learning : A social-semiotic look

In this paper, we present a case study of a pair of students as they use nondisciplinary communicative practices to mechanistically reason about binary star dynamics. To do so, we first review and bring together the theoretical perspectives of social semiotics and embodied cognition, therein developing a new methodological approach for analyzing student interactions during the learning of physics (particularly for those interactions involving students’ bodies). Through the use of our new approach, we are able to show how students combine a diverse range of meaning-making resources into complex, enacted analogies, thus forming explanatory models that are grounded in embodied intuition. We reflect on how meaning-making resources—even when not physically persistent—can act as coordinating hubs for other resources as well as how we might further nuance the academic conversation around the role of the body in physics learning.Title in Licentiate thesis list of papers: A social-semiotic look at embodiment in physics learning</p