Negotiated matter: a robotic exploration of craft-driven innovation

This paper introduces a novel approach to craft-driven robotic innovation in architectural research. Here craft is not portrayed as a source of ornamental or historical inspiration, but instead as an open-ended process described by a framework involving material properties, diverging modes of knowledge production and representation, emergent tectonic configurations and embodied interaction with technology. To do so, this paper firstly contrasts a definition of craft (Pye 1968) with practices of robotic architectural production. Additionally, the notion of emergent tectonics resulting from negotiated material and technological processes is addressed by critically situating the theories of architectural tectonics by Kenneth Frampton (2001) and digital tectonics by Leach, Turnbull and Williams (2004) in the context of robotic fabrication in architecture. Finally, the ongoing project “Computing Craft” is presented as a case study illustrating a proposed framework for robotic craft-driven innovation

Heating of refractory cathodes by high-pressure arc plasmas: II

A model of the near-cathode plasma layer in a plasma under a pressure of the order of one or several bars is reconsidered on the basis of recent theoretical results. Physics of the near-cathode layer is analysed in the range of near-cathode voltage drops of up to 50 V, in accord to recent experimental results which have shown that the near-cathode voltage drop in high-pressure arc discharges may be that high. It is found that a non-monotony of the dependence of the energy flux density on the surface temperature at fixed values of the near-cathode voltage drop is caused by one of the three mechanisms: overcoming of the increase of combined ion and plasma electron heating by the increase of thermionic cooling as the plasma approaches full ionization; non-monotony of the dependence of the ion current on the electron temperature which is caused by the deviation of the ion current from the diffusion value; rapid increase of the plasma electron heating which is subsequently overcome by thermionic cooling. A closed description of the plasma–cathode interaction is obtained by numerically solving the nonlinear boundary-value problem for the temperature distribution inside the cathode body. Results of numerical modelling of the diffuse discharge under conditions of a model arc lamp are given and a good agreement with the experimental data is shown. 1