2 resultados para pick-and-place robot

em QSpace: Queen's University - Canada


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In the later decades of the nineteenth century and the early decades of the twentieth, large numbers of Canadian women were stepping out of the shadows of private life and into the public world of work and political action. Among them, both a cause and an effect of these sweeping social changes, was the first generation of Canadian women to work as professional authors. Although these women were not unified by ideology, genre, or date of birth, they are studied here as a generation defined by their time and place in history, by their material circumstances, and by their collective accomplishment. Chapters which focus on E. Pauline Johnson (Tekahionwake), the Eaton sisters (Sui Sin Far and Onoto Watanna), Joanna E. Wood, and Sara Jeannette Duncan explore some of the many commonalities and interrelationships among the members of this generation as a whole. This project combines archival research with analytical bibliography in order to clarify and extend our knowledge of Johnson’s and Duncan’s professional lives and publishing histories, and to recover some of Wood’s “lost” stories. This research offers a preliminary sketch of the long tradition of the platform performance (both Native and non-Native) with which Johnson and others engaged. It explores the uniquely innovative ethnographic writings of Johnson, Duncan, and the Eaton sisters, among others, and it explores thematic concerns which relate directly to the experiences of working women. Whether or not I convince other scholars to treat these authors as a generation, with more in common than has previously been supposed, the strong parallels revealed in these pages will help to clarify and contextualize some of their most interesting work.

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In this thesis, the origin of large-scale structures in hot star winds, believed to be responsible for the presence of discrete absorption components (DACs) in the absorption troughs of ultraviolet resonance lines, is constrained using both observations and numerical simulations. These structures are understood as arising from bright regions on the stellar surface, although their physical cause remains unknown. First, we use high quality circular spectropolarimetric observations of 13 well-studied OB stars to evaluate the potential role of dipolar magnetic fields in producing DACs. We perform longitudinal field measurements and place limits on the field strength using Bayesian inference, assuming that it is dipolar. No magnetic field was detected within this sample. The derived constraints statistically refute any significant dynamical influence from a magnetic dipole on the wind for all of these stars, ruling out such fields as a cause for DACs. Second, we perform numerical simulations using bright spots constrained by broadband optical photometric observations. We calculate hydrodynamical wind models using three sets of spot sizes and strengths. Co-rotating interaction regions are yielded in each model, and radiative transfer shows that the properties of the variations in the UV resonance lines synthesized from these models are consistent with those found in observed UV spectra, establishing the first consistent link between UV spectroscopic line profile variability and photometric variations and thus supporting the bright spot paradigm (BSP). Finally, we develop and apply a phenomenological model to quantify the measurable effects co-rotating bright spots would have on broadband optical photometry and on the profiles of photopheric lines in optical spectra. This model can be used to evaluate the existence of these spots, and, in the event of their detection, characterize them. Furthermore, a tentative spot evolution model is presented. A preliminary analysis of its output, compared to the observed photometric variations of xi Persei, suggests the possible existence of “active longitudes” on the surface of this star. Future work will expand the range of observational diagnostics that can be interpreted within the BSP, and link phenomenology (bright spots) to physical processes (magnetic spots or non-radial pulsations).