Performance of fixed‐parameter control algorithms on high‐rise structures equipped with semi‐active tuned mass dampers

The present study investigates the performance of fixed parameter control algorithms on wind‐excited high‐rise structures equipped with semi‐active tuned mass dampers of variable damping. It has been demonstrated that the algorithms that increase significantly the performance of the controlled structure do so at the expense of damper strokes. When the maximum damper strokes are capped to progressively lower limits, the efficacy of different algorithms, measured through a number of performance objectives, drastically alters totally changing the performance ranking of them and pointing out the need for an extensive study of the interplay between loading, control algorithm and allowable stroke within the design of semi‐active tuned mass dampers devices. 2015 The Authors. The Structural Design of Tall and Special Buildings published by John Wiley & Sons Ltd.     

Organochlorine and organophosphoric insecticides, herbicides and heavy metals residue in industrial wastewaters in Cyprus

Most industries in Cyprus possess permits either for disposal at central wastewater treatment plants (the treated effluent of which is reused or disposed into the sea), or discharge on soil, or reuse either for irrigation or groundwater recharge or discharge into the sea. A preliminary investigation undertaken by the University of Cyprus in regards to dangerous substances was the first step towards establishing a new licensing and monitoring system. Liquid-liquid extraction was used for the extraction of the selected pesticides from wastewaters. Gas chromatography with two different detection methods (ECD and FTD) was applied for the determination of 17 pesticides (12 organochlorine insecticides, 3 organophosphoric insecticides and 2 herbicides). In addition ICP and a mercury evaporation unit were used to determine the concentrations of heavy metals in the samples. The results revealed the presence of several priority substances in wastewaters, in most cases at concentrations well below the regulatory limits. Non-compliance was observed for a limited number of metals. Sixteen out of 17 organic substances that were monitored for 1-year period time were traced in different wastewater streams. What was found out is that there is a need to expand the analytical determinations and the monitoring to more wastewater streams and more priority substances, in order to safeguard the water resources in Cyprus.     

Modal consensus observers for distributed parameter systems

This article proposes a new type of a consensus protocol for the synchronization of distributed observers in systems governed by parabolic partial differential equations. Addressing the goal of sharing useful information among distributed observers, it delves into the details governing the modal decompositions of distributed parameter systems. Assuming that two different groups of sensors are available to provide process information to the two distributed observers, the proposed modal consensus design ensures that only useful information is transmitted to the requisite modal components of each of the observers. Without any consensus protocol, the observers capture different frequency content of the spatial process in differing degrees, as it relates to the concept of modal observability. Their modal components exhibit different learning behavior toward the process state. In the extreme case, it turns out that certain modal components of the distributed observers occasionally behave as naïve observers. To ensure that, both collectively and modal componentwise, the observers agree both with the process state and with each other, a modal component consensus protocol is proposed. Such a consensus protocol is mono-directional and provides only useful information necessary to the appropriate modal component of the distributed filters that behaves as a naïve modal observer. This protocol, when abstracted and applied to different state decompositions can be viewed as mono-directional projections of information transmitted and received by the participating distributed observers. Detailed numerical studies of advection PDE in one and two spatial dimensions are included to elucidate the details of the proposed modal consensus observers.     

A distributed control and parameter estimation protocol with prescribed performance for homogeneous lagrangian multi-agent systems

In this paper, we consider the formation control problem for uncertain homogeneous Lagrangian nonlinear multi-agent systems in a leader-follower scheme under a directed communication protocol. A distributed adaptive control protocol of minimal complexity is proposed that achieves prescribed, arbitrarily fast and accurate formation establishment as well as synchronization of the parameter estimates of all followers. The estimation and control laws are distributed in the sense that the control signal and the update laws are calculated based solely on local relative state information. Moreover, provided that the communication graph is strongly connected and contrary to the related works on multi-agent systems, the controller-imposed transient and steady state performance bounds are fully decoupled from: (i) the underlying graph topology, (ii) the control gains selection and (iii) the agents’ model uncertainties. Finally, extensive simulation studies on the attitude control of flying spacecrafts clarify and verify the approach.     

Mineralisation of the antibiotic amoxicillin in pure and surface waters by artificial UVA‐ and sunlight‐induced Fenton oxidation

BACKGROUND: The degradation and mineralisation of the antibiotic amoxicillin by photo‐Fenton reactions, mediated by artificial UVA or solar irradiation, were investigated. Experiments were conducted with 30 mg L^?1 amoxicillin solutions prepared with deionised or surface water at Fe²⁺ and H₂O₂ concentrations in the range 0.0179–0.0895 and 1–10 mmol L^?1, respectively. Black‐light irradiation at 365 nm was provided by a 13 W m^?2 lamp, while samples were exposed to sunlight at 20 W m^?2 for solar experiments. RESULTS: In all cases, quantitative amoxicillin degradation occurred within 5 min and this was accompanied by lower mineralisation rates. Mineralisation followed first‐order kinetics with respect to organic carbon content and it was not affected by the water matrix with either type of illumination. Solar‐induced reactions were only marginally faster than artificial irradiation. Increasing the H₂O₂ to Fe²⁺ concentration ratio increases the extent of mineralisation up to a point beyond which degradation is impeded due to radical scavenging associated with the high concentrations of the Fenton reagents. CONCLUSION: Amoxicillin is readily degradable by homogeneous photocatalysis, being converted to more stable intermediates as indicated by lower mineralisation rates. The process can be driven by solar irradiation, thus providing a sustainable treatment technology. Copyright © 2009 Society of Chemical Industry