Aprehender dibujando: los dibujos de Luis Borobio

Este artículo es una contribución al entendimiento del dibujo como aprehensión de su objeto, en general, y de la arquitectura, en particular, es decir, como definición de lo tangible que luego se materializará en la obra. Para ello, tomamos como referencia algunos dibujos de Luis Borobio (1924-2005), arquitecto y catedrático de Estética, poeta y caricaturista, que ilustran sus libros y cuyo valor, como apuntes a mano alzada, es el de dar a entender, de manera sencilla y eficaz, aquello que representan. De este estudio se desprende su capacidad para la transmisión de conocimiento, el sentido del boceto como metáfora y de la caricatura como crítica, herramientas con las que la mano llega a conocer y dar a conocer su objeto. Se añade una reflexión final sobre Mi árbol, verdadero manual de expresión gráfica, idóneo para contribuir a esclarecer la dialéctica entre masa y espacio que es propia de toda arquitectura.

Study of the emissions from pyrolytic and oxidative thermal decomposition of PVC

Polyvinyl chloride (PVC) is one of the plastics most extensively used due to its versatility. The demand of PVC resin in Europe during 2012 reached 5000 ktonnes1. PVC waste management is a big problem because of the high volume generated all over the world and its chlorine content. End-of-life PVC is mainly mixed with municipal solid waste (MSW) and one common disposal option for this is waste-to-energy incineration (WtE). The presence of plastics such as PVC in the fuel mix increases the heating value of the fuel. PVC has two times higher energy content than MSW ‒around 20 MJ/kg vs 10 MJ/kg, respectively. However, the high chlorine content in PVC resin, 57 wt.%, may be a source for the formation of hazardous chlorinated organic pollutants in thermal processes. Chlorine present in the feedstock of WtE plants plays an important role in the formation of (i) chlorine (Cl2) and (ii) hydrochloric gas (HCl), both of them responsible for corrosion, and (iii) chlorinated organic pollutants2. In this work, pyrolytic and oxidative thermal degradation of PVC resin were carried out in a laboratory scale reactor at 500 ºC in order to analyze the influence of the reaction atmosphere on the emissions evolved. Special emphasis was put on the analysis of chlorinated organic pollutants such as polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs) and other related compounds like polychlorobenzenes (PCBzs), polychlorophenols (PCPhs) and polycyclic aromatic hydrocarbons (PAHs). Another objective of this work was to compare the results with those of a previous work3 in which emissions at different temperatures in both pyrolysis and combustion of another PVC resin had been studied; in that case, experiments for PCDD/Fs emissions had been performed only at 850 ºC.