Use of anion clay hydrotalcite to remove coloured organics from aqueous solutions

Anion clay hydrotalcite sorbents were prepared to investigate their adsorption capabilities in the removal of coloured organic substances from various aqueous systems. Anion clay hydrotalcite was found to be particularly effective at removing negatively charged species. Its excellent uptake levels of anionic species can be accounted for by its high surface area and anion exchange ability. That is, coloured substances can be adsorbed on the surface or enter the interlayer region of the clay by anion exchange. In the adsorption of Acid Blue 29 on the anion clay hydrotalcite, an equilibrium time of 1 h with dye removal exceeding 99% was obtained. The hydrotalcite was found to have an adsorption capacity marginally below that of commercial activated carbon. It should be noted that the spent sorbents can be regenerated easily by heating at 723 K to remove all adsorbed organics. The reused sorbents displayed greater adsorption capabilities than the newly prepared hydrotalcite. Hence, the anion clay hydrotalcite is easily recoverable and reusable such that it is a promising sorbent for environmental and purification purposes. (C) 2002 Elsevier Science B.V. All rights reserved.

Coloured Petri nets and graphical simulation for the validation of a robotic cell in aircraft industry

This paper proposes a mixed validation approach based on coloured Petri nets and 3D graphic simulation for the design of supervisory systems in manufacturing cells with multiple robots. The coloured Petri net is used to model the cell behaviour at a high level of abstraction. It models the activities of each cell component and its coordination by a supervisory system. The graphical simulation is used to analyse and validate the cell behaviour in a 3D environment, allowing the detection of collisions and the calculation of process times. The motivation for this work comes from the aeronautic industry. The automation of a fuselage assembly process requires the integration of robots with other cell components such as metrological or vision systems. In this cell, the robot trajectories are defined by the supervisory system and results from the coordination of the cell components. The paper presents the application of the approach for an aircraft assembly cell under integration in Brazil. This case study shows the feasibility of the approach and supports the discussion of its main advantages and limits. (C) 2011 Elsevier Ltd. All rights reserved.

Photoinhibition in differently coloured juvenile leaves of Syzygium species

Photoinhibition, as measured by the dark-adapted chlorophyll a fluorescence ratio F-v/F-m, was assessed in Syzygium moorei, a species with dark green juvenile leaves, Syzygium corynanthum, which has light green juvenile leaves, and two species with pink-red juvenile leaves (Syzygium wilsonii and Syzygium luehmannii). All plants were glasshouse-grown (maximum PPFD 1500 mu mol m(-2) s(-1)) under optimum nutrition and water. When measured at midday, dark-adapted F-v/F-m ratios of juvenile leaves gradually increased in art species as percentage of full leaf expansion (% FLE) increased. Fluorescence measurement 3 h after sunset or pre-dawn also showed a developmental effect on F-v/F-m, with juvenile leaves of S, luehmannii and S. wilsonii showing much lower F-v/F-m at all stages of development. Dark-adapted F-v/F-m values in both juvenile and mature leaves generally never exceeded 0.8 at any stage in any of the species. Courses of F-v/F-m on sunny days showed greater diurnal photoinhibition in green juvenile (c, 50% FLE) leaves of S, moorei (24%) and S, corynanthum (36%) than in mature leaves of the previous flush in these species (<10%), Diurnal photoinhibition was statistically similar (18-24%) in pink-red juvenile and green mature leaves of S, luehmannii and S, wilsonii. Re-positioning juvenile leaves of S, wilsonii horizontally increased diurnal photoinhibition, Exposure of leaves to a standard mild photoinhibitory right treatment (30 min at 1000 mu mol m(-2) s(-1)) showed that juvenile leaves of air species had a lower percentage of high energy state quenching (qE) and a higher percentage of photoinhibitory quenching (ql) than mature leaves.

Energy-dispersive x-ray fluorescence analysis of modern coloured glasses from Marinha Grande (Portugal)

X-Ray Spectrom. 2003; 32: 396–401

Tailored deposition of coloured coatings: on the widening of the available colour range

Dissertação de mestrado integrado em Engenharia de Materiais

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